fix(core): retain unsaved session tokens

Retry token persistence when the keyring reports a missing session.
oo7 can hide locked entries, so discarding the pending rotation leaves
a spent refresh token in the saved session.

Refs #78

.github/ISSUE_TEMPLATE/config.yml

@@ -3,6 +3,9 @@ contact_links:
   - name: Security vulnerability
     url: https://github.com/narrrl/proton-drive-linux/security/advisories/new
     about: Report privately — never in a public issue.
+  - name: Troubleshooting and FAQ
+    url: https://github.com/narrrl/proton-drive-linux/wiki/Troubleshooting
+    about: Fixes for common problems, and what to include in a bug report.
   - name: Known issues
     url: https://github.com/narrrl/proton-drive-linux/blob/main/docs/BUGS.md
     about: The authoritative ledger of tracked bugs and their status.

.github/PULL_REQUEST_TEMPLATE.md

@@ -21,6 +21,7 @@ cargo test --workspace --locked
 - [ ] Touches recovery, staging, or anything that can be the only copy of user data
 - [ ] Changes packaging, the systemd unit, or desktop entries
 - [ ] Changes the control protocol (daemon and front ends updated together)
+- [ ] Adds or renames a page in `docs/` (listed in `SECTIONS` in `scripts/publish-wiki.sh`, which publishes it to the wiki)
 - [ ] None of the above
 
 <!-- Screenshots for GTK changes. -->

.github/workflows/ci.yml

@@ -45,7 +45,7 @@ jobs:
         run: cargo fmt --all -- --check
 
       - name: Lints
-        run: cargo clippy --workspace --all-targets -- -D warnings
+        run: cargo clippy --workspace --all-targets --locked -- -D warnings
 
       - name: Unit tests
         run: cargo test --workspace --locked
@@ -66,8 +66,9 @@ jobs:
 
   # The seeded simulation runs (docs/TESTING.md): real FUSE
   # daemons against an in-memory Drive, so they need /dev/fuse but no account.
+  # They run on pull requests too: most data-loss fixes are only exercised
+  # here, and a change that breaks one should not reach main first.
   simulation:
-    if: github.event_name != 'pull_request'
     runs-on: ubuntu-24.04
     timeout-minutes: 30
 

.github/workflows/copr.yml

@@ -0,0 +1,66 @@
+name: COPR
+
+on:
+  # Called by release.yml once the GitHub release and its assets exist: COPR
+  # downloads the tag archive and the vendored crates from the release.
+  workflow_call:
+    inputs:
+      version:
+        required: true
+        type: string
+    secrets:
+      COPR_CONFIG:
+        required: true
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Release to build, such as 3.5.0. It must already have its vendor tarball.'
+        required: true
+        type: string
+
+permissions:
+  contents: read
+
+concurrency:
+  group: copr
+  cancel-in-progress: false
+
+jobs:
+  build:
+    name: Build in COPR
+    runs-on: ubuntu-24.04
+    container: fedora:latest
+    env:
+      VERSION: ${{ inputs.version }}
+      COPR_PROJECT: narl-rs/proton-drive-linux
+
+    steps:
+      - name: Install packaging tools
+        run: dnf -y install copr-cli rpm-build rpmdevtools
+
+      - name: Checkout repository
+        uses: actions/checkout@v7
+
+      - name: Configure COPR access
+        env:
+          COPR_CONFIG: ${{ secrets.COPR_CONFIG }}
+        run: |
+          install -d -m700 ~/.config
+          printf '%s\n' "$COPR_CONFIG" > ~/.config/copr
+          chmod 600 ~/.config/copr
+
+      # COPR rebuilds the source package without our --define, so the version
+      # has to be written into the spec itself.
+      - name: Build the source package
+        run: |
+          version="${VERSION#v}"
+          spec=packaging/proton-drive-linux.spec
+          sed -i -E "s/^(%\{!\?version: %global version )[^}]*\}/\1${version}}/" "$spec"
+          grep -qF "%global version ${version}}" "$spec"
+          mkdir -p rpmbuild/SOURCES
+          spectool -g -C rpmbuild/SOURCES "$spec"
+          rpmbuild -bs --define "_topdir $PWD/rpmbuild" "$spec"
+
+      # Waits for the build, so a failed COPR build fails this job.
+      - name: Submit to COPR
+        run: copr-cli build "$COPR_PROJECT" rpmbuild/SRPMS/*.src.rpm

.github/workflows/nix.yml

@@ -38,6 +38,13 @@ jobs:
 
       - uses: cachix/install-nix-action@v31
 
+      # Pulls from the project's binary cache, and pushes what this run built
+      # when the token is there; a fork's pull request has none and only pulls.
+      - uses: cachix/cachix-action@v17
+        with:
+          name: proton-drive-linux
+          authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+
       - name: Check the flake
         run: nix flake check --print-build-logs --no-build
 

.github/workflows/release.yml

@@ -52,8 +52,10 @@ jobs:
           tag_version="${GITHUB_REF_NAME#v}"
           manifest_version="$(sed -n 's/^version = "\([^"]*\)"/\1/p' Cargo.toml | head -n1)"
           pkgbuild_version="$(sed -n 's/^pkgver=//p' packaging/PKGBUILD | head -n1)"
+          spec_version="$(sed -n 's/^%{!?version: %global version \([^}]*\)}/\1/p' packaging/proton-drive-linux.spec)"
           test "$tag_version" = "$manifest_version"
           test "$tag_version" = "$pkgbuild_version"
+          test "$tag_version" = "$spec_version"
 
       - name: Release quality gates
         run: |
@@ -129,6 +131,12 @@ jobs:
           # Create tarball
           tar -czf proton-drive-linux-${{ env.VERSION }}-x86_64.tar.gz -C dist/binaries .
 
+      # Every crate the build needs, so COPR can build the spec without network.
+      - name: Package vendored crates (.tar.xz)
+        run: |
+          cargo vendor --locked dist/vendor > /dev/null
+          tar -cJf proton-drive-linux-vendor-${{ env.VERSION }}.tar.xz -C dist vendor
+
       - name: Package Debian package (.deb)
         run: |
           mkdir -p deb/DEBIAN
@@ -152,6 +160,10 @@ jobs:
           cp packaging/proton-drive.service deb/usr/lib/systemd/user/
           cp LICENSE deb/usr/share/licenses/proton-drive-linux/
           po/build.sh deb/usr/share/locale
+          packaging/completions.sh target/release/pdfs deb/usr/share
+
+          # Stops the running daemon before removal, so the mount stops mirroring deletes
+          install -m755 packaging/deb/prerm deb/DEBIAN/prerm
 
           # Calculate Installed-Size in KB for the control file
           INSTALLED_SIZE=$(du -sk deb | cut -f1)
@@ -227,27 +239,75 @@ jobs:
           path: |
             *.deb
             *.tar.gz
+            *.tar.xz
             *.rpm
           if-no-files-found: error
 
+  # The flake is the Nix release: a tag is what `github:narrrl/proton-drive-linux/vX.Y.Z`
+  # pins, so it has to build before the release is announced.
+  nix:
+    name: Build the Nix package
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v7
+
+      - uses: cachix/install-nix-action@v31
+
+      # Pulls from the project's binary cache, and pushes what this run built
+      # when the token is there; a fork's pull request has none and only pulls.
+      - uses: cachix/cachix-action@v17
+        with:
+          name: proton-drive-linux
+          authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+
+      - name: Build the flake
+        run: nix build --print-build-logs .#proton-drive-linux
+
+      - name: Check the version
+        run: |
+          built="$(./result/bin/pdfs --version)"
+          echo "$built"
+          case "$GITHUB_REF" in
+            refs/tags/v*) grep -qF "${GITHUB_REF_NAME#v}" <<< "$built" ;;
+          esac
+
   publish:
     name: Create GitHub Release
-    needs: [checks, build-release]
+    needs: [checks, build-release, nix]
     if: startsWith(github.ref, 'refs/tags/')
     runs-on: ubuntu-24.04
 
     steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
       - name: Download packages
         uses: actions/download-artifact@v8
         with:
           name: proton-drive-linux-builds
 
+      # The release notes are this version's section of the changelog, from its
+      # heading up to the next one.
+      - name: Extract release notes
+        run: |
+          version="${GITHUB_REF_NAME#v}"
+          awk -v heading="## [$version]" \
+            'index($0, heading) == 1 { found = 1; print; next }
+             found && /^## \[/ { exit }
+             found' docs/CHANGELOG.md > release-notes.md
+          if [ ! -s release-notes.md ]; then
+            echo "::error::docs/CHANGELOG.md has no section for $version"
+            exit 1
+          fi
+
       - name: Create GitHub Release
         uses: softprops/action-gh-release@v3
         with:
+          body_path: release-notes.md
           files: |
             *.deb
             *.tar.gz
+            *.tar.xz
             *.rpm
           draft: false
           prerelease: false
@@ -263,3 +323,21 @@ jobs:
       version: ${{ github.ref_name }}
     secrets:
       AUR_SSH_PRIVATE_KEY: ${{ secrets.AUR_SSH_PRIVATE_KEY }}
+
+  copr:
+    name: Build COPR packages
+    needs: publish
+    if: startsWith(github.ref, 'refs/tags/')
+    uses: ./.github/workflows/copr.yml
+    with:
+      version: ${{ github.ref_name }}
+    secrets:
+      COPR_CONFIG: ${{ secrets.COPR_CONFIG }}
+
+  wiki:
+    name: Publish the wiki
+    needs: publish
+    if: startsWith(github.ref, 'refs/tags/')
+    uses: ./.github/workflows/wiki.yml
+    with:
+      ref: ${{ github.ref_name }}

.github/workflows/wiki.yml

@@ -0,0 +1,77 @@
+name: Wiki
+
+# docs/ is the source of the GitHub wiki (docs/DEVELOPMENT.md#common-changes).
+# Every change to the documentation checks its links; release.yml calls this
+# once the release is published, so the wiki documents the latest release. Run
+# it from the Actions tab to publish main in between.
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'docs/**'
+      - 'images/**'
+      - 'README.md'
+      - 'CONTRIBUTING.md'
+      - 'SECURITY.md'
+      - 'scripts/publish-wiki.sh'
+      - '.github/workflows/wiki.yml'
+  pull_request:
+    paths:
+      - 'docs/**'
+      - 'images/**'
+      - 'README.md'
+      - 'CONTRIBUTING.md'
+      - 'SECURITY.md'
+      - 'scripts/publish-wiki.sh'
+      - '.github/workflows/wiki.yml'
+  workflow_call:
+    inputs:
+      ref:
+        description: 'Tag or branch to publish'
+        required: true
+        type: string
+  workflow_dispatch:
+    inputs:
+      ref:
+        description: 'Tag or branch to publish'
+        required: false
+        default: 'main'
+        type: string
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    name: Check documentation links
+    if: inputs.ref == ''
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Check links
+        run: scripts/publish-wiki.sh --check "$RUNNER_TEMP"
+
+  publish:
+    name: Publish to the wiki
+    # Set only by release.yml and the Actions tab, so pushes and pull requests
+    # never publish.
+    if: inputs.ref != ''
+    runs-on: ubuntu-24.04
+    concurrency:
+      group: wiki-publish
+      cancel-in-progress: false
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          ref: ${{ inputs.ref }}
+
+      - name: Publish
+        env:
+          WIKI_REMOTE: https://x-access-token:${{ github.token }}@github.com/${{ github.repository }}.wiki.git
+        run: |
+          git config --global user.name 'github-actions[bot]'
+          git config --global user.email '41898282+github-actions[bot]@users.noreply.github.com'
+          scripts/publish-wiki.sh --push "$RUNNER_TEMP"

CONTRIBUTING.md

@@ -6,10 +6,10 @@ deliberately high — everything else is ordinary Rust review.
 
 ## Before you start
 
-- Read [`AGENTS.md`](AGENTS.md) for repository conventions,
-  [`docs/DEVELOPMENT.md`](docs/DEVELOPMENT.md) for building, running and debugging from source,
-  and [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for how the daemon, front ends, and SDK fit
-  together. [`docs/README.md`](docs/README.md) indexes the rest.
+- Read [`docs/DEVELOPMENT.md`](docs/DEVELOPMENT.md) for building, running and debugging from
+  source, and [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for how the daemon, front ends, and
+  SDK fit together. [`docs/README.md`](docs/README.md) indexes the rest. The same pages are on
+  the [wiki](https://github.com/narrrl/proton-drive-linux/wiki).
 - Check [`docs/BUGS.md`](docs/BUGS.md) — it is the authoritative issue ledger, and your problem may
   already be tracked there with context.
 - For anything larger than a fix, open an issue first so the design can be discussed before you
@@ -58,8 +58,10 @@ runs are destructive: use a dedicated test account, never one holding data you c
   catalog in `po/LINGUAS` in the same change. See [`docs/TRANSLATING.md`](docs/TRANSLATING.md).
   The CLI and daemon messages stay in English.
 - **Document what users see.** A new command, setting or behaviour belongs in the matching page
-  under `docs/` (user guide, CLI reference or configuration) and in the `[Unreleased]` section of
-  [`docs/CHANGELOG.md`](docs/CHANGELOG.md).
+  under `docs/` (a user guide topic, the CLI reference or configuration) and in the `[Unreleased]`
+  section of [`docs/CHANGELOG.md`](docs/CHANGELOG.md). Each release publishes `docs/` to the
+  wiki. A new page goes into `SECTIONS` in `scripts/publish-wiki.sh`, and
+  `scripts/publish-wiki.sh --check` must pass. CI runs it on every change to `docs/`.
 
 ## Commits and pull requests
 

Cargo.toml

@@ -3,7 +3,7 @@ resolver = "2"
 members = ["crates/pdfs-core", "crates/pdfs-fuse", "crates/pdfs-cli", "crates/pdfs-gui"]
 
 [workspace.package]
-version = "3.2.0"
+version = "3.8.0"
 edition = "2024"
 license = "MIT"
 authors = ["Nils Pukropp <contact@narl.io>"]
@@ -15,8 +15,9 @@ keywords = ["proton", "drive", "fuse", "sync", "linux"]
 categories = ["filesystem", "command-line-utilities"]
 
 [workspace.dependencies]
-proton-sdk = { version = "0.8.2" }
-proton-drive-rs = { version = "0.8.2" }
+proton-sdk = { version = "0.11.0" }
+proton-drive-rs = { version = "0.11.0" }
+chrono = { version = "0.4", default-features = false, features = ["std"] }
 
 # Internal crates.
 pdfs-core = { path = "crates/pdfs-core" }
@@ -33,7 +34,7 @@ anyhow = "1"
 # wedge every later acquisition of it: `Workers` catches the unwind to keep the
 # pool alive, and `std::sync::Mutex` would defeat that by poisoning the state
 # the recovered worker needs.
-parking_lot = "0.12"
+parking_lot = "0.13"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 directories = "6"
@@ -41,7 +42,7 @@ ignore = "0.4"
 sha2 = "0.11"
 # Google Takeout exports are zip sets; the importer reads their central
 # directories and streams entries out without extracting to disk first.
-zip = { version = "8", default-features = false, features = ["deflate"] }
+zip = { version = "9", default-features = false, features = ["deflate"] }
 # Proton's photo duplicate detection is keyed on the plaintext SHA-1, so an
 # import has to speak SHA-1 whatever its age.
 sha1 = "0.11"
@@ -49,15 +50,30 @@ sha1 = "0.11"
 # formats a camera or phone actually produces — the rest of the crate's codecs
 # would be dead weight in the daemon.
 image = { version = "0.25", default-features = false, features = ["jpeg", "png", "webp", "gif", "tiff", "bmp", "rayon"] }
-rusqlite = { version = "0.40", features = ["bundled"] }
+rusqlite = { version = "0.41", features = ["bundled"] }
 # keyring 4 split into `keyring-core` plus per-platform stores. The libdbus
 # Secret Service store is the one keyring 3's `sync-secret-service` wrapped, and
 # with no `target` it matches items v3 wrote, so existing logins survive.
 keyring-core = "1"
 dbus-secret-service-keyring-store = { version = "1", features = ["crypto-rust"] }
 clap = { version = "4", features = ["derive"] }
+# `unstable-dynamic`: Tab calls `pdfs` back, so arguments complete from the
+# running service. Only `pdfs-cli/src/complete.rs` uses it.
+clap_complete = { version = "4.6", features = ["unstable-dynamic"] }
 rpassword = "7"
 async-trait = "0.1"
 futures = "0.3"
 fuser = "0.18"
 libc = "0.2"
+
+[profile.release]
+# No package ships a separate debug package (the PKGBUILD sets `!debug`, the
+# RPM spec sets `debug_package` to nil), and the unstripped binaries weighed
+# 43 MB (`pdfs`), 24 MB (`pdfs-app`) and 12 MB (`pdfs-tray`).
+strip = "symbols"
+# Off on purpose: LTO has broken GTK links for this workspace, which is why
+# the packages turn it off as well.
+lto = false
+# `Workers` and the thumbnail build catch panics to keep the daemon alive, so
+# unwinding must stay on.
+panic = "unwind"

README.md

@@ -73,16 +73,30 @@ scriptable CLI.
 
 | Distribution | Package |
 |---|---|
-| Debian, Ubuntu 24.04 or newer | `.deb` from the [latest release](https://github.com/narrrl/proton-drive-linux/releases/latest) |
-| Fedora 44 or newer | `.rpm` from the [latest release](https://github.com/narrrl/proton-drive-linux/releases/latest) |
+| Fedora 44 or newer | [`narl-rs/proton-drive-linux`](https://copr.fedorainfracloud.org/coprs/narl-rs/proton-drive-linux/) in COPR, updated with `dnf upgrade` |
 | Arch Linux | [`proton-drive-for-linux`](https://aur.archlinux.org/packages/proton-drive-for-linux) (also `-bin` and `-git`) in the AUR |
-| NixOS | The flake in this repository: see [Install → NixOS](docs/INSTALL.md#nixos-flake) |
+| Debian, Ubuntu 24.04 or newer | `.deb` from the [latest release](https://github.com/narrrl/proton-drive-linux/releases/latest) |
+| NixOS | The flake in this repository: see [Installation → NixOS](docs/INSTALL.md#nixos-flake) |
 | Anything else | [Build from source](docs/INSTALL.md#build-from-source) |
 
+**Fedora**
+
 ```bash
-sudo apt install ./proton-drive-linux_*.deb        # Debian, Ubuntu
-sudo dnf install ./proton-drive-linux-*.rpm        # Fedora
-paru -S proton-drive-for-linux                     # Arch
+sudo dnf copr enable narl-rs/proton-drive-linux
+sudo dnf install proton-drive-linux
+```
+
+**Arch Linux**
+
+```bash
+paru -S proton-drive-for-linux
+```
+
+**Debian and Ubuntu:** download the `.deb` from the
+[latest release](https://github.com/narrrl/proton-drive-linux/releases/latest), then:
+
+```bash
+sudo apt install ./proton-drive-linux_*_amd64.deb
 ```
 
 Then open **Proton Drive** from your applications menu and sign in. The app starts the background
@@ -97,18 +111,25 @@ systemctl --user enable --now proton-drive.service
 pdfs status
 ```
 
-[docs/INSTALL.md](docs/INSTALL.md) has the requirements, optional extras (tray on GNOME, RAW and
-video thumbnails), headless use and uninstalling.
+New to the client? [Getting started](docs/GETTING_STARTED.md) walks through the first steps.
+[Installation](docs/INSTALL.md) has the optional extras (tray on GNOME, RAW and video
+thumbnails), updating, headless use and uninstalling.
 
 ## Documentation
 
+The documentation is in [`docs/`](docs/README.md) and on the
+[wiki](https://github.com/narrrl/proton-drive-linux/wiki).
+
 | | |
 |---|---|
+| [Getting started](docs/GETTING_STARTED.md) | From installing to your first synced folder |
 | [User guide](docs/USER_GUIDE.md) | Everything the app, tray and launcher do |
-| [Command-line reference](docs/CLI.md) | Every `pdfs` command and scripting with `--json` |
+| [FAQ](docs/FAQ.md) | Short answers to common questions |
+| [Command-line reference](docs/CLI.md) | Every `pdfs` command, Tab completion and scripting with `--json` |
 | [Configuration](docs/CONFIGURATION.md) | `config.json`, file locations, environment variables, the service |
 | [Troubleshooting](docs/TROUBLESHOOTING.md) | Diagnosing problems and fixing common ones |
 | [Recovering on a new computer](docs/RECOVERY.md) | Getting your synced folders back after a reinstall or a lost machine |
+| [Security model](docs/SECURITY_MODEL.md) | What protects your files, what stays on this computer, what the client connects to |
 | [Changelog](docs/CHANGELOG.md) | What changed in each release |
 
 For contributors: [development guide](docs/DEVELOPMENT.md), [architecture](docs/ARCHITECTURE.md),
@@ -150,7 +171,8 @@ keys before it leaves the machine, through a Rust implementation of Proton's Dri
 
 Files you open are decrypted into a local cache so programs can read them. What that means for
 the security of the machine is spelled out in the
-[threat model](docs/ARCHITECTURE.md#10-threat-model-what-this-client-writes-to-disk-in-plaintext).
+[security model](docs/SECURITY_MODEL.md#what-is-kept-on-this-computer), and in full detail in
+the [threat model](docs/ARCHITECTURE.md#10-threat-model-what-this-client-writes-to-disk-in-plaintext).
 
 ## Contributing
 

SECURITY.md

@@ -4,6 +4,9 @@
 
 Fixes land on the latest release. Please reproduce on the most recent version before reporting.
 
+For what the client protects and what it does not, written for users, see the
+[security model](docs/SECURITY_MODEL.md).
+
 ## Reporting a vulnerability
 
 **Do not open a public issue.** Report privately through GitHub's

crates/pdfs-cli/Cargo.toml

@@ -21,6 +21,7 @@ anyhow.workspace = true
 tracing.workspace = true
 tracing-subscriber.workspace = true
 clap.workspace = true
+clap_complete.workspace = true
 rpassword.workspace = true
 serde_json.workspace = true
 zeroize.workspace = true

crates/pdfs-cli/src/complete.rs

@@ -0,0 +1,731 @@
+//! Shell completion for `pdfs`.
+//!
+//! Built on clap_complete's dynamic engine: the script a shell loads is a thin
+//! stub that calls `pdfs` back on every Tab with the words typed so far, and
+//! `pdfs` answers from its own clap definition. That lets an argument complete
+//! from the running service as well as from the command tree — `pdfs sync rm
+//! <Tab>` offers the synced-folder ids with their paths, `pdfs pin Doc<Tab>`
+//! walks My files.
+//!
+//! Every value that comes from the service is best effort. With no service, a
+//! slow one or an error, a completer offers nothing: a Tab that hangs or prints
+//! an error into the prompt is worse than one that does nothing.
+//!
+//! The engine sits behind clap_complete's `unstable-dynamic` feature, so all of
+//! this crate's use of it is kept to this module.
+
+use std::ffi::{OsStr, OsString};
+use std::path::{Path, PathBuf};
+use std::time::Duration;
+
+use clap::CommandFactory;
+use clap_complete::engine::{CompletionCandidate, PathCompleter, ValueCompleter};
+use clap_complete::env::{Bash, CompleteEnv, Elvish, EnvCompleter, Fish, Powershell, Zsh};
+use pdfs_core::control::{
+    AlbumInfo, BookmarkInfo, ConflictInfo, DeviceInfo, DirEntry, InvitationInfo, PendingOpInfo,
+    PublicLinkInfo, Request, Response, RevisionInfo, ShareEntry, ShareEntryKind, SyncFolderInfo,
+};
+
+/// The environment variable that turns a run of `pdfs` into a completion
+/// request. Not clap's generic `COMPLETE`: the same binary is the systemd
+/// daemon, and an unrelated `COMPLETE` in its environment must not stop it.
+pub const VAR: &str = "PDFS_COMPLETE";
+
+/// How long a completer waits for the service. A Tab is interactive, so a
+/// listing the service cannot give soon is better skipped. Long enough for the
+/// listings that ask Proton (computers take over a second).
+const SERVICE_TIMEOUT: Duration = Duration::from_secs(2);
+
+/// How long a listing that asks Proton is reused. Every Tab is a new `pdfs`, so
+/// without it `pdfs devices rm <Tab>`, a letter and another Tab would wait for
+/// Proton twice. A uid that went away in the meantime only fails the command.
+const CACHE_TTL: Duration = Duration::from_secs(30);
+
+/// Answer a completion request and exit, if this run is one. Must run before
+/// anything writes to stdout.
+pub fn handle_request() {
+    CompleteEnv::with_factory(crate::Cli::command)
+        .var(VAR)
+        .complete();
+}
+
+/// The shells `pdfs completions` writes a script for.
+#[derive(Clone, Copy, clap::ValueEnum)]
+pub enum ShellArg {
+    Bash,
+    Zsh,
+    Fish,
+    Elvish,
+    Powershell,
+}
+
+impl ShellArg {
+    fn completer(self) -> &'static dyn EnvCompleter {
+        match self {
+            ShellArg::Bash => &Bash,
+            ShellArg::Zsh => &Zsh,
+            ShellArg::Fish => &Fish,
+            ShellArg::Elvish => &Elvish,
+            ShellArg::Powershell => &Powershell,
+        }
+    }
+}
+
+/// Write the script that registers `pdfs` completion with `shell`.
+///
+/// The script calls `pdfs` from `PATH`, not this binary's path, so one written
+/// at packaging time keeps working once installed.
+pub fn write_script(shell: ShellArg, out: &mut dyn std::io::Write) -> std::io::Result<()> {
+    shell
+        .completer()
+        .write_registration(VAR, "pdfs", "pdfs", "pdfs", out)?;
+    if let ShellArg::Zsh = shell {
+        // Installed as `_pdfs` in site-functions, the script is autoloaded as
+        // that function's body on the first Tab. The body above only defines
+        // and registers the completer, so this line also runs it, or the first
+        // Tab would complete nothing. Sourced, `funcstack` names no `_pdfs`.
+        writeln!(
+            out,
+            "if [ \"$funcstack[1]\" = \"_pdfs\" ]; then\n    _clap_dynamic_completer_pdfs \"$@\"\nfi"
+        )?;
+    }
+    Ok(())
+}
+
+// ---------------------------------------------------------------------------
+// Talking to the service
+
+/// One request to the service, or `None` if there is no answer worth showing.
+fn ask(request: Request) -> Option<Response> {
+    let socket = pdfs_core::config::AppDirs::new().ok()?.control_socket();
+    ask_at(&socket, &request)
+}
+
+fn ask_at(socket: &Path, request: &Request) -> Option<Response> {
+    match pdfs_core::control::send_with_timeout(socket, request, SERVICE_TIMEOUT) {
+        Ok(Response::Error { .. }) | Err(_) => None,
+        Ok(response) => Some(response),
+    }
+}
+
+/// [`ask`] for a listing that comes from Proton rather than the local
+/// database, reusing an answer younger than [`CACHE_TTL`]. `key` names the
+/// listing's cache file.
+fn ask_cached(key: &str, request: Request) -> Option<Response> {
+    let file = cache_file(key);
+    if let Some(hit) = file.as_deref().and_then(read_fresh) {
+        return Some(hit);
+    }
+    let response = ask(request)?;
+    if let Some(file) = &file {
+        write_cache(file, &response);
+    }
+    Some(response)
+}
+
+/// In `$XDG_RUNTIME_DIR`: private to the user, in memory and gone at logout,
+/// which suits names from the account. With no runtime dir, nothing is cached.
+fn cache_file(key: &str) -> Option<PathBuf> {
+    let runtime = PathBuf::from(std::env::var_os("XDG_RUNTIME_DIR")?);
+    Some(
+        runtime
+            .join("proton-drive-linux")
+            .join(format!("completion-{key}.json")),
+    )
+}
+
+fn read_fresh(file: &Path) -> Option<Response> {
+    let age = std::fs::metadata(file)
+        .ok()?
+        .modified()
+        .ok()?
+        .elapsed()
+        .ok()?;
+    if age > CACHE_TTL {
+        return None;
+    }
+    serde_json::from_slice(&std::fs::read(file).ok()?).ok()
+}
+
+/// Best effort: a cache that cannot be written only costs the next Tab a wait.
+fn write_cache(file: &Path, response: &Response) {
+    use std::os::unix::fs::{DirBuilderExt, OpenOptionsExt};
+
+    let (Some(dir), Ok(json)) = (file.parent(), serde_json::to_vec(response)) else {
+        return;
+    };
+    let _ = std::fs::DirBuilder::new()
+        .recursive(true)
+        .mode(0o700)
+        .create(dir);
+    let staging = file.with_extension(format!("{}.tmp", std::process::id()));
+    let written = std::fs::OpenOptions::new()
+        .write(true)
+        .create_new(true)
+        .mode(0o600)
+        .open(&staging)
+        .and_then(|mut f| std::io::Write::write_all(&mut f, &json));
+    if written.is_err() || std::fs::rename(&staging, file).is_err() {
+        let _ = std::fs::remove_file(&staging);
+    }
+}
+
+fn candidate(value: impl Into<OsString>, help: impl Into<String>) -> CompletionCandidate {
+    let help = help.into();
+    let candidate = CompletionCandidate::new(value);
+    if help.is_empty() {
+        candidate
+    } else {
+        candidate.help(Some(help.into()))
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Paths in Proton Drive
+
+/// A path in the mount: an absolute path completes from the local filesystem
+/// (through the mount), anything else from the service's listing of My files,
+/// which is what the commands resolve a relative path against.
+pub fn drive_path(current: &OsStr) -> Vec<CompletionCandidate> {
+    complete_drive(current, false)
+}
+
+/// [`drive_path`] for an argument that must be a folder.
+pub fn drive_dir(current: &OsStr) -> Vec<CompletionCandidate> {
+    complete_drive(current, true)
+}
+
+/// `pdfs refresh`: a folder, or one of the two named caches.
+pub fn refresh_target(current: &OsStr) -> Vec<CompletionCandidate> {
+    let typed = current.to_string_lossy();
+    let mut candidates: Vec<_> = [
+        ("trash", "the trash listing"),
+        ("photos", "the photos timeline"),
+    ]
+    .into_iter()
+    .filter(|(name, _)| name.starts_with(typed.as_ref()))
+    .map(|(name, help)| candidate(name, help))
+    .collect();
+    candidates.extend(drive_dir(current));
+    candidates
+}
+
+fn complete_drive(current: &OsStr, dirs_only: bool) -> Vec<CompletionCandidate> {
+    let Some(word) = current.to_str() else {
+        return Vec::new();
+    };
+    if word.starts_with('/') || word.starts_with('~') {
+        let local = if dirs_only {
+            PathCompleter::dir()
+        } else {
+            PathCompleter::any()
+        };
+        return local.complete(current);
+    }
+    let (parent, prefix) = split_drive_word(word);
+    let listing = Request::ListDir {
+        path: parent.trim_end_matches('/').to_owned(),
+    };
+    match ask(listing) {
+        Some(Response::Entries { entries }) => {
+            drive_candidates(parent, prefix, &entries, dirs_only)
+        }
+        _ => Vec::new(),
+    }
+}
+
+/// Split a typed drive path into the folder to list (with its trailing `/`)
+/// and the start of the name being completed in it.
+fn split_drive_word(word: &str) -> (&str, &str) {
+    match word.rfind('/') {
+        Some(at) => word.split_at(at + 1),
+        None => ("", word),
+    }
+}
+
+/// The entries of `parent` whose name starts with `prefix`. A folder ends in
+/// `/`, which tells every shell not to add a space after it, so the next Tab
+/// goes on into it.
+fn drive_candidates(
+    parent: &str,
+    prefix: &str,
+    entries: &[DirEntry],
+    dirs_only: bool,
+) -> Vec<CompletionCandidate> {
+    entries
+        .iter()
+        .filter(|e| e.name.starts_with(prefix) && (e.is_dir || !dirs_only))
+        .map(|e| {
+            let slash = if e.is_dir { "/" } else { "" };
+            CompletionCandidate::new(format!("{parent}{}{slash}", e.name))
+                .hide(e.name.starts_with('.') && !prefix.starts_with('.'))
+        })
+        .collect()
+}
+
+// ---------------------------------------------------------------------------
+// Ids and uids from the service's listings
+
+pub fn sync_folder_id() -> Vec<CompletionCandidate> {
+    match ask(Request::ListSyncFolders) {
+        Some(Response::SyncFolders { items }) => sync_folder_candidates(&items),
+        _ => Vec::new(),
+    }
+}
+
+fn sync_folder_candidates(items: &[SyncFolderInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|f| candidate(f.id.to_string(), format!("{} ({})", f.local_path, f.mode)))
+        .collect()
+}
+
+pub fn queue_id() -> Vec<CompletionCandidate> {
+    match ask(Request::ListPendingOps) {
+        Some(Response::PendingOps { items }) => queue_candidates(&items),
+        _ => Vec::new(),
+    }
+}
+
+fn queue_candidates(items: &[PendingOpInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|op| candidate(op.id.to_string(), format!("{} {}", op.kind, op.path)))
+        .collect()
+}
+
+pub fn device_uid() -> Vec<CompletionCandidate> {
+    match ask_cached("devices", Request::ListDevices) {
+        Some(Response::Devices { items }) => device_candidates(&items),
+        _ => Vec::new(),
+    }
+}
+
+fn device_candidates(items: &[DeviceInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|d| {
+            let this = if d.this_device {
+                " (this computer)"
+            } else {
+                ""
+            };
+            candidate(d.uid.as_str(), format!("{}{this}", d.name))
+        })
+        .collect()
+}
+
+pub fn trash_uid() -> Vec<CompletionCandidate> {
+    match ask_cached("trash", Request::ListTrash) {
+        Some(Response::Entries { entries }) => trash_candidates(&entries),
+        _ => Vec::new(),
+    }
+}
+
+fn trash_candidates(entries: &[DirEntry]) -> Vec<CompletionCandidate> {
+    entries
+        .iter()
+        .map(|e| {
+            let help = match e.trashed_from.as_deref() {
+                Some(from) if !from.is_empty() => format!("{} (from {from})", e.name),
+                _ => e.name.clone(),
+            };
+            candidate(e.uid.as_str(), help)
+        })
+        .collect()
+}
+
+pub fn album_uid() -> Vec<CompletionCandidate> {
+    match ask_cached("albums", Request::PhotoAlbums) {
+        Some(Response::Albums { items, .. }) => album_candidates(&items),
+        _ => Vec::new(),
+    }
+}
+
+fn album_candidates(items: &[AlbumInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|a| candidate(a.uid.as_str(), a.name.as_str()))
+        .collect()
+}
+
+pub fn shared_uid() -> Vec<CompletionCandidate> {
+    match ask_cached("shared-with-me", Request::ListSharedWithMe) {
+        Some(Response::Entries { entries }) => shared_candidates(&entries),
+        _ => Vec::new(),
+    }
+}
+
+fn shared_candidates(entries: &[DirEntry]) -> Vec<CompletionCandidate> {
+    entries
+        .iter()
+        .map(|e| {
+            let help = if e.shared_by.is_empty() {
+                e.name.clone()
+            } else {
+                format!("{} (from {})", e.name, e.shared_by)
+            };
+            candidate(e.uid.as_str(), help)
+        })
+        .collect()
+}
+
+pub fn invitation_id() -> Vec<CompletionCandidate> {
+    match ask_cached("invitations", Request::ListInvitations) {
+        Some(Response::Invitations { items }) => invitation_candidates(&items),
+        _ => Vec::new(),
+    }
+}
+
+fn invitation_candidates(items: &[InvitationInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|i| {
+            let help = match i.name.as_deref() {
+                Some(name) => format!("{name} from {}", i.inviter_email),
+                None => format!("from {}", i.inviter_email),
+            };
+            candidate(i.id.as_str(), help)
+        })
+        .collect()
+}
+
+pub fn bookmark_token() -> Vec<CompletionCandidate> {
+    match ask_cached("bookmarks", Request::ListBookmarks) {
+        Some(Response::Bookmarks { items }) => bookmark_candidates(&items),
+        _ => Vec::new(),
+    }
+}
+
+fn bookmark_candidates(items: &[BookmarkInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|b| candidate(b.token.as_str(), b.name.as_deref().unwrap_or(&b.url)))
+        .collect()
+}
+
+pub fn conflict_path() -> Vec<CompletionCandidate> {
+    match ask(Request::ListConflicts) {
+        Some(Response::Conflicts { items }) => conflict_candidates(&items),
+        _ => Vec::new(),
+    }
+}
+
+fn conflict_candidates(items: &[ConflictInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|c| candidate(c.path.as_str(), format!("copy of {}", c.original_path)))
+        .collect()
+}
+
+// ---------------------------------------------------------------------------
+// Ids that belong to the path typed before them
+
+/// A version of the file named earlier on the line (`pdfs versions restore
+/// <path> <Tab>`).
+pub fn version_id(current: &OsStr) -> Vec<CompletionCandidate> {
+    let Some(path) = typed_path() else {
+        return Vec::new();
+    };
+    match ask(Request::ListRevisions { path }) {
+        Some(Response::Revisions { items }) => starting_with(current, revision_candidates(&items)),
+        _ => Vec::new(),
+    }
+}
+
+fn revision_candidates(items: &[RevisionInfo]) -> Vec<CompletionCandidate> {
+    items
+        .iter()
+        .map(|r| {
+            let current = if r.is_active { ", current" } else { "" };
+            let size = r.claimed_size.unwrap_or(r.size_on_storage).max(0);
+            candidate(
+                r.id.as_str(),
+                format!(
+                    "{}, {}{current}",
+                    crate::format_epoch_utc(r.created),
+                    crate::human_bytes(size as u64)
+                ),
+            )
+        })
+        .collect()
+}
+
+/// A member or invitation on the share of the path typed earlier on the line.
+pub fn share_entry_id(current: &OsStr) -> Vec<CompletionCandidate> {
+    match share_of_typed_path() {
+        Some((entries, _)) => starting_with(current, share_entry_candidates(&entries)),
+        None => Vec::new(),
+    }
+}
+
+fn share_entry_candidates(entries: &[ShareEntry]) -> Vec<CompletionCandidate> {
+    entries
+        .iter()
+        .map(|e| {
+            // The kind is the next argument, so the help names it in the words
+            // that argument takes.
+            let kind = match e.kind {
+                ShareEntryKind::Member => "member",
+                ShareEntryKind::ProtonInvite => "proton",
+                ShareEntryKind::ExternalInvite => "external",
+            };
+            candidate(e.id.as_str(), format!("{} ({}, {kind})", e.email, e.role))
+        })
+        .collect()
+}
+
+/// The public link of the path typed earlier on the line.
+pub fn public_link_id(current: &OsStr) -> Vec<CompletionCandidate> {
+    match share_of_typed_path() {
+        Some((_, Some(link))) => starting_with(current, vec![public_link_candidate(&link)]),
+        _ => Vec::new(),
+    }
+}
+
+/// Described without its URL: the fragment is the link's password, and a Tab
+/// menu is on screen for anyone watching.
+fn public_link_candidate(link: &PublicLinkInfo) -> CompletionCandidate {
+    let help = match link.expires {
+        Some(expires) => format!(
+            "{} link, expires {}",
+            link.role,
+            crate::format_epoch_utc(expires)
+        ),
+        None => format!("{} link", link.role),
+    };
+    candidate(link.id.as_str(), help)
+}
+
+fn share_of_typed_path() -> Option<(Vec<ShareEntry>, Option<PublicLinkInfo>)> {
+    match ask(Request::ListShare {
+        path: typed_path()?,
+    })? {
+        Response::Share { entries, link } => Some((entries, link)),
+        _ => None,
+    }
+}
+
+/// [`clap_complete::engine::ArgValueCompleter`] candidates are not filtered by
+/// the engine, unlike [`clap_complete::engine::ArgValueCandidates`].
+fn starting_with(
+    current: &OsStr,
+    candidates: Vec<CompletionCandidate>,
+) -> Vec<CompletionCandidate> {
+    let typed = current.to_string_lossy();
+    candidates
+        .into_iter()
+        .filter(|c| c.get_value().to_string_lossy().starts_with(typed.as_ref()))
+        .collect()
+}
+
+/// The `path` argument of the command being completed, as the service takes
+/// it. A completer only receives the word under the cursor, so this reads the
+/// line from the process arguments, where the shell's stub passes it.
+fn typed_path() -> Option<String> {
+    let args: Vec<OsString> = std::env::args_os().collect();
+    let index = std::env::var("_CLAP_COMPLETE_INDEX")
+        .ok()
+        .and_then(|i| i.parse().ok());
+    path_in(words_before_cursor(&args, index))
+}
+
+/// The words of the line before the one being completed. The stub runs
+/// `pdfs -- <words>`; bash, zsh and elvish say which word the cursor is on,
+/// fish and PowerShell pass the line cut at the cursor, so it is the last.
+fn words_before_cursor(args: &[OsString], index: Option<usize>) -> Vec<OsString> {
+    let start = args
+        .iter()
+        .position(|a| a == "--")
+        .map_or(args.len(), |at| at + 1);
+    let mut words = args[start..].to_vec();
+    let index = index.unwrap_or(words.len().saturating_sub(1));
+    words.truncate(index);
+    words
+}
+
+/// Parse `words` as far as they go and take the innermost command's `path`.
+fn path_in(words: Vec<OsString>) -> Option<String> {
+    let matches = crate::Cli::command()
+        .ignore_errors(true)
+        .try_get_matches_from(words)
+        .ok()?;
+    let mut leaf = &matches;
+    while let Some((_, sub)) = leaf.subcommand() {
+        leaf = sub;
+    }
+    let path = leaf.try_get_one::<PathBuf>("path").ok().flatten()?;
+    crate::path_arg(path).ok()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn values(candidates: &[CompletionCandidate]) -> Vec<String> {
+        candidates
+            .iter()
+            .map(|c| c.get_value().to_string_lossy().into_owned())
+            .collect()
+    }
+
+    fn help(candidate: &CompletionCandidate) -> String {
+        candidate
+            .get_help()
+            .map(ToString::to_string)
+            .unwrap_or_default()
+    }
+
+    fn entry(name: &str, is_dir: bool) -> DirEntry {
+        serde_json::from_value(serde_json::json!({
+            "name": name,
+            "is_dir": is_dir,
+            "size": 0,
+            "modified": 0,
+            "pinned": false,
+            "uid": format!("vol~{name}"),
+        }))
+        .unwrap()
+    }
+
+    fn words(line: &[&str]) -> Vec<OsString> {
+        line.iter().map(OsString::from).collect()
+    }
+
+    #[test]
+    fn the_command_definition_is_valid() {
+        crate::Cli::command().debug_assert();
+    }
+
+    #[test]
+    fn completions_script_is_written_for_every_shell() {
+        for shell in [
+            ShellArg::Bash,
+            ShellArg::Zsh,
+            ShellArg::Fish,
+            ShellArg::Elvish,
+            ShellArg::Powershell,
+        ] {
+            let mut script = Vec::new();
+            write_script(shell, &mut script).unwrap();
+            let script = String::from_utf8(script).unwrap();
+            assert!(script.contains(VAR), "{script}");
+            assert!(script.contains("pdfs"), "{script}");
+        }
+    }
+
+    #[test]
+    fn drive_path_splits_parent_and_prefix() {
+        assert_eq!(split_drive_word(""), ("", ""));
+        assert_eq!(split_drive_word("Doc"), ("", "Doc"));
+        assert_eq!(split_drive_word("Documents/"), ("Documents/", ""));
+        assert_eq!(split_drive_word("Documents/Rep"), ("Documents/", "Rep"));
+        assert_eq!(split_drive_word("a/b/c"), ("a/b/", "c"));
+    }
+
+    #[test]
+    fn drive_dirs_end_in_a_slash() {
+        let entries = [
+            entry("Reports", true),
+            entry("Receipt.pdf", false),
+            entry("Other", true),
+        ];
+        let all = drive_candidates("Documents/", "Re", &entries, false);
+        assert_eq!(
+            values(&all),
+            ["Documents/Reports/", "Documents/Receipt.pdf"]
+        );
+        let dirs = drive_candidates("Documents/", "", &entries, true);
+        assert_eq!(values(&dirs), ["Documents/Reports/", "Documents/Other/"]);
+    }
+
+    #[test]
+    fn hidden_drive_entries_need_a_typed_dot() {
+        let entries = [entry(".git", true)];
+        assert!(drive_candidates("", "", &entries, false)[0].is_hide_set());
+        assert!(!drive_candidates("", ".", &entries, false)[0].is_hide_set());
+    }
+
+    #[test]
+    fn sync_folder_ids_complete_with_their_local_path() {
+        let folders: Vec<SyncFolderInfo> = serde_json::from_value(serde_json::json!([{
+            "id": 3,
+            "local_path": "/home/me/Documents",
+            "remote_uid": "vol~docs",
+            "mode": "mirror",
+            "state": "idle",
+            "last_sync": 0,
+        }]))
+        .unwrap();
+        let candidates = sync_folder_candidates(&folders);
+        assert_eq!(values(&candidates), ["3"]);
+        assert_eq!(help(&candidates[0]), "/home/me/Documents (mirror)");
+    }
+
+    #[test]
+    fn trash_uids_complete_with_their_name() {
+        let mut from_docs = entry("a.pdf", false);
+        from_docs.trashed_from = Some("Documents".into());
+        let candidates = trash_candidates(&[from_docs, entry("b", true)]);
+        assert_eq!(values(&candidates), ["vol~a.pdf", "vol~b"]);
+        assert_eq!(help(&candidates[0]), "a.pdf (from Documents)");
+        assert_eq!(help(&candidates[1]), "b");
+    }
+
+    #[test]
+    fn completer_without_a_service_offers_nothing() {
+        let dir = std::env::temp_dir().join(format!("pdfs-complete-{}", std::process::id()));
+        let socket = dir.join("control.sock");
+        assert!(ask_at(&socket, &Request::ListSyncFolders).is_none());
+    }
+
+    #[test]
+    fn cached_listing_is_reused_until_it_is_stale() {
+        let dir = std::env::temp_dir().join(format!("pdfs-complete-cache-{}", std::process::id()));
+        let file = dir.join("completion-devices.json");
+        write_cache(&file, &Response::Devices { items: Vec::new() });
+        assert!(matches!(read_fresh(&file), Some(Response::Devices { .. })));
+        let mode = std::os::unix::fs::PermissionsExt::mode(
+            &std::fs::metadata(&file).unwrap().permissions(),
+        );
+        assert_eq!(mode & 0o777, 0o600);
+
+        let stale = std::time::SystemTime::now() - CACHE_TTL - Duration::from_secs(1);
+        std::fs::File::options()
+            .write(true)
+            .open(&file)
+            .unwrap()
+            .set_modified(stale)
+            .unwrap();
+        assert!(read_fresh(&file).is_none());
+        std::fs::remove_dir_all(dir).unwrap();
+    }
+
+    #[test]
+    fn words_before_cursor_stop_at_the_cursor() {
+        let args = words(&[
+            "pdfs", "--", "pdfs", "versions", "restore", "a.txt", "", "x",
+        ]);
+        assert_eq!(
+            words_before_cursor(&args, Some(4)),
+            words(&["pdfs", "versions", "restore", "a.txt"])
+        );
+        // fish: the line arrives cut at the cursor, the current word last.
+        let fish = words(&["pdfs", "--", "pdfs", "versions", "restore", "a.txt", "ab"]);
+        assert_eq!(
+            words_before_cursor(&fish, None),
+            words(&["pdfs", "versions", "restore", "a.txt"])
+        );
+    }
+
+    #[test]
+    fn completing_words_finds_the_path_before_the_id() {
+        let line = words(&["pdfs", "versions", "restore", "Documents/a.txt"]);
+        assert_eq!(path_in(line).as_deref(), Some("Documents/a.txt"));
+        let line = words(&["pdfs", "--json", "share-role", "Shared/x"]);
+        assert_eq!(path_in(line).as_deref(), Some("Shared/x"));
+        let line = words(&["pdfs", "public-link", "update", "--role", "editor", "a"]);
+        assert_eq!(path_in(line).as_deref(), Some("a"));
+        assert_eq!(path_in(words(&["pdfs", "versions", "restore"])), None);
+    }
+}

crates/pdfs-cli/src/journal.rs

@@ -0,0 +1,122 @@
+//! Log priorities for journald.
+//!
+//! journald files each line a service writes at the unit's default priority,
+//! info, unless the line opens with a syslog `<N>` prefix. Without one every
+//! WARN and ERROR the daemon logs is stored as info, and the
+//! `journalctl -p warning` that the troubleshooting guide asks for shows
+//! nothing (`docs/BUGS.md` B258).
+
+use std::fmt;
+use std::os::unix::fs::MetadataExt;
+
+use tracing::{Event, Level, Subscriber};
+use tracing_subscriber::fmt::format::Writer;
+use tracing_subscriber::fmt::{FmtContext, FormatEvent, FormatFields};
+use tracing_subscriber::registry::LookupSpan;
+
+/// Whether standard output is the journal stream systemd connected this
+/// process to.
+///
+/// `JOURNAL_STREAM` alone does not say so: a terminal started from a user unit
+/// inherits it, and every `pdfs` run in that terminal would print the
+/// prefixes. systemd sets it to the stream's `device:inode`, so it is compared
+/// against what fd 1 actually is.
+pub(crate) fn stdout_is_journal() -> bool {
+    let Some(stream) = std::env::var_os("JOURNAL_STREAM") else {
+        return false;
+    };
+    let Ok(stdout) = std::fs::metadata("/proc/self/fd/1") else {
+        return false;
+    };
+    stream
+        .to_str()
+        .is_some_and(|value| names_stream(value, stdout.dev(), stdout.ino()))
+}
+
+/// Whether a `JOURNAL_STREAM` value names the file `dev`:`ino`.
+fn names_stream(value: &str, dev: u64, ino: u64) -> bool {
+    value
+        .split_once(':')
+        .is_some_and(|(d, i)| d.parse() == Ok(dev) && i.parse() == Ok(ino))
+}
+
+/// The syslog priority journald should file a `level` line at.
+fn priority(level: &Level) -> u8 {
+    match *level {
+        Level::ERROR => 3,
+        Level::WARN => 4,
+        Level::INFO => 6,
+        Level::DEBUG | Level::TRACE => 7,
+    }
+}
+
+/// An event format that opens each line with its `<N>` priority, then writes
+/// the line as `F` would.
+pub(crate) struct Prioritized<F>(pub(crate) F);
+
+impl<S, N, F> FormatEvent<S, N> for Prioritized<F>
+where
+    S: Subscriber + for<'a> LookupSpan<'a>,
+    N: for<'a> FormatFields<'a> + 'static,
+    F: FormatEvent<S, N>,
+{
+    fn format_event(
+        &self,
+        ctx: &FmtContext<'_, S, N>,
+        mut writer: Writer<'_>,
+        event: &Event<'_>,
+    ) -> fmt::Result {
+        write!(writer, "<{}>", priority(event.metadata().level()))?;
+        self.0.format_event(ctx, writer, event)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::io;
+    use std::sync::{Arc, Mutex};
+
+    #[derive(Clone)]
+    struct Buf(Arc<Mutex<Vec<u8>>>);
+
+    impl io::Write for Buf {
+        fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
+            self.0.lock().unwrap().extend_from_slice(bytes);
+            Ok(bytes.len())
+        }
+        fn flush(&mut self) -> io::Result<()> {
+            Ok(())
+        }
+    }
+
+    #[test]
+    fn each_line_opens_with_the_priority_of_its_level() {
+        let buf = Buf(Arc::new(Mutex::new(Vec::new())));
+        let writer = buf.clone();
+        let subscriber = tracing_subscriber::fmt()
+            .with_max_level(Level::DEBUG)
+            .with_ansi(false)
+            .with_writer(move || writer.clone())
+            .event_format(Prioritized(tracing_subscriber::fmt::format()))
+            .finish();
+        tracing::subscriber::with_default(subscriber, || {
+            tracing::error!("e");
+            tracing::warn!("w");
+            tracing::info!("i");
+            tracing::debug!("d");
+        });
+        let out = String::from_utf8(buf.0.lock().unwrap().clone()).unwrap();
+        let prefixes: Vec<&str> = out.lines().map(|line| &line[..3]).collect();
+        assert_eq!(prefixes, ["<3>", "<4>", "<6>", "<7>"]);
+    }
+
+    #[test]
+    fn journal_stream_must_name_the_same_file() {
+        assert!(names_stream("8:12345", 8, 12345));
+        assert!(!names_stream("8:12345", 8, 54321));
+        assert!(!names_stream("9:12345", 8, 12345));
+        assert!(!names_stream("8", 8, 12345));
+        assert!(!names_stream("", 8, 12345));
+    }
+}

crates/pdfs-core/Cargo.toml

@@ -12,6 +12,7 @@ description = "Core auth/session/config for the Proton Drive Linux client"
 [dependencies]
 proton-sdk.workspace = true
 proton-drive-rs.workspace = true
+chrono.workspace = true
 tokio.workspace = true
 serde.workspace = true
 serde_json.workspace = true
@@ -30,3 +31,4 @@ async-trait.workspace = true
 libc.workspace = true
 zeroize.workspace = true
 base64.workspace = true
+exif = { version = "0.6", package = "kamadak-exif" }

crates/pdfs-core/src/auth.rs

@@ -516,8 +516,59 @@ pub fn lock(forget: bool) -> Result<()> {
     Ok(())
 }
 
-/// Forget the persisted session (best-effort; absent entry is not an error).
-pub fn logout() -> Result<()> {
+/// How long [`logout`] waits for Proton to end the session before it signs
+/// out locally without.
+const END_SESSION_TIMEOUT: Duration = Duration::from_secs(10);
+
+/// End the stored session on Proton's side (`DELETE auth/v4`). Returns false
+/// when there is none or Proton could not be reached in time.
+///
+/// Runs on a thread of its own, so it works the same whether the caller is
+/// inside a tokio runtime or not.
+fn end_server_session() -> bool {
+    let Ok(stored) = load() else {
+        return false;
+    };
+    let ended = std::thread::scope(|scope| {
+        scope
+            .spawn(|| -> std::result::Result<(), String> {
+                let rt = tokio::runtime::Builder::new_current_thread()
+                    .enable_all()
+                    .build()
+                    .map_err(|e| e.to_string())?;
+                rt.block_on(async {
+                    let session = resume_stored(&stored).map_err(|e| e.to_string())?;
+                    match tokio::time::timeout(END_SESSION_TIMEOUT, session.end()).await {
+                        Ok(result) => result.map_err(|e| e.to_string()),
+                        Err(_) => Err(format!(
+                            "no answer within {}s",
+                            END_SESSION_TIMEOUT.as_secs()
+                        )),
+                    }
+                })
+            })
+            .join()
+            .unwrap_or_else(|_| Err("the sign-out thread panicked".into()))
+    });
+    match ended {
+        Ok(()) => true,
+        Err(error) => {
+            tracing::warn!(%error, "ending the session on Proton failed; signing out locally");
+            false
+        }
+    }
+}
+
+/// End the session on Proton, then forget it here. Returns whether Proton
+/// ended it: offline, the session stays valid on Proton's side until it
+/// expires or is signed out from the account's security settings.
+///
+/// Before this, signing out only deleted the keyring entry. The tokens stayed
+/// valid on Proton, so a copy of them taken from this machine still worked.
+///
+/// The local half is best effort; an absent entry is not an error.
+pub fn logout() -> Result<bool> {
+    let ended = end_server_session();
     // The persisted entity cache describes the account being logged out of. It
     // is encrypted under a key derived from that account's passphrases, but
     // leaving it behind would also mean the next account inherits a store it can
@@ -539,7 +590,7 @@ pub fn logout() -> Result<()> {
     }
     let _ = kernelkey::UNSAVED_TOKENS.clear();
     match keyring_entry()?.delete_credential() {
-        Ok(()) | Err(keyring_core::Error::NoEntry) => Ok(()),
+        Ok(()) | Err(keyring_core::Error::NoEntry) => Ok(ended),
         Err(e) => Err(e.into()),
     }
 }
@@ -945,21 +996,15 @@ impl TokenSink {
         }
     }
 
-    /// Write the unsaved rotation, if there is one. A blob that moved on, or
-    /// is gone with a logout, drops it: there is nothing it may still go into.
+    /// Write the unsaved rotation, if there is one. A blob that moved on drops
+    /// it. A missing blob is retried: some Secret Service providers also report
+    /// locked or temporarily hidden items as absent. Never recreate it here.
     fn flush(&self) -> Result<()> {
         let mut state = self.state.lock();
         let Some(tokens) = state.unsaved.clone() else {
             return Ok(());
         };
-        let mut stored = match load() {
-            Ok(stored) => stored,
-            Err(Error::NotLoggedIn) => {
-                state.settle();
-                return Ok(());
-            }
-            Err(e) => return Err(e),
-        };
+        let mut stored = load()?;
         match take_rotation(
             &mut stored,
             &self.session_id,
@@ -1255,6 +1300,47 @@ mod tests {
         }
     }
 
+    /// oo7 0.7.0 reports a locked collection's items as absent (upstream #614).
+    /// Treating that as logout loses the only live tokens (B284, issue #78).
+    #[test]
+    fn a_temporarily_missing_session_does_not_discard_a_rotation() {
+        let _turn = mock_keyring();
+        write_stored(&stored_with("r")).unwrap();
+        let sink = Arc::new(TokenSink::new("s", "r".into()));
+        let entry = keyring_entry().unwrap();
+        entry
+            .as_any()
+            .downcast_ref::<keyring_core::mock::Cred>()
+            .unwrap()
+            .set_error(keyring_core::Error::NoEntry);
+
+        assert!(sink.rotated(tokens("a2", "r2")).is_err());
+        assert!(sink.state.lock().unsaved.is_some());
+        assert_eq!(load().unwrap().refresh_token, "r");
+
+        sink.flush().unwrap();
+        assert_eq!(load().unwrap().refresh_token, "r2");
+        assert!(sink.state.lock().unsaved.is_none());
+    }
+
+    #[test]
+    fn retrying_a_missing_session_never_recreates_it_or_overwrites_a_new_login() {
+        let _turn = mock_keyring();
+        let sink = TokenSink::new("s", "r".into());
+        sink.state.lock().unsaved = Some(tokens("a2", "r2"));
+
+        assert!(matches!(sink.flush(), Err(Error::NotLoggedIn)));
+        assert!(matches!(load(), Err(Error::NotLoggedIn)));
+        assert!(sink.state.lock().unsaved.is_some());
+
+        let mut login = stored_with("fresh");
+        login.session_id = "new".into();
+        write_stored(&login).unwrap();
+        sink.flush().unwrap();
+        assert!(sink.state.lock().unsaved.is_none());
+        assert_eq!(load().unwrap().refresh_token, "fresh");
+    }
+
     #[test]
     fn an_unsaved_rotation_goes_only_into_the_blob_it_was_refused_for() {
         let unsaved = UnsavedRotation {

crates/pdfs-core/src/cache.rs

@@ -621,10 +621,20 @@ impl ContentCache {
             for entry in rd.flatten() {
                 let name = entry.file_name();
                 let Some(name) = name.to_str() else { continue };
+                // A `.meta` tags the blob named like it without the suffix. One
+                // whose blob is gone is what an eviction leaves between its two
+                // removals, by a crash or by a store of the same uid landing in
+                // between, and nothing else would ever remove it.
+                if let Some(blob) = name.strip_suffix(".meta") {
+                    if !dir.join(blob).exists() {
+                        let _ = std::fs::remove_file(entry.path());
+                    }
+                    continue;
+                }
                 // `.geom` is a block-geometry sidecar (see `GeometryMeta`), tens
                 // of bytes and not a cached block; like `.meta` it is neither
                 // budgeted nor evictable on its own.
-                if name.ends_with(".meta") || name.ends_with(".geom") {
+                if name.ends_with(".geom") {
                     continue;
                 }
                 // A `.tmp` is a staging file from a store that never completed
@@ -2250,6 +2260,28 @@ mod tests {
         assert!(total <= 8, "budget enforced after reconcile, total={total}");
     }
 
+    /// An eviction removes the blob, then its tag. A crash in between, or a
+    /// store of the same uid landing in between, left the tag on its own, and
+    /// nothing removed it.
+    #[test]
+    fn a_tag_without_its_blob_is_swept_at_open() {
+        let dir = TempDir::new();
+        let content = dir.path().join("content");
+        let pins = dir.path().join("pins.json");
+        let db = Arc::new(Db::open_in_memory().unwrap());
+        {
+            let c = ContentCache::open(content.clone(), pins.clone(), 0, db.clone()).unwrap();
+            c.store(&uid("kept"), 1, 4, b"kept").unwrap();
+            c.store(&uid("gone"), 1, 4, b"gone").unwrap();
+            std::fs::remove_file(c.blob_path(&uid("gone"))).unwrap();
+        }
+
+        let c = ContentCache::open(content, pins, 0, db).unwrap();
+        assert!(!c.meta_path(&uid("gone")).exists());
+        assert!(c.meta_path(&uid("kept")).exists());
+        assert_eq!(c.read_range(&uid("kept"), 1, 4, 0, 4).unwrap(), b"kept");
+    }
+
     #[test]
     fn stale_metadata_is_a_miss() {
         let (c, _d) = cache();

crates/pdfs-core/src/config.rs

@@ -163,6 +163,14 @@ pub struct AppConfig {
     /// Defaulted for configs predating the field.
     #[serde(default)]
     pub files_view: FilesView,
+    /// How the desktop app's Photos page lays out its grid. Defaulted for
+    /// configs predating the field.
+    #[serde(default)]
+    pub photos_view: PhotosView,
+    /// The desktop app's main window size, remembered between runs. Defaulted
+    /// for configs predating the field.
+    #[serde(default)]
+    pub window: WindowState,
     /// The user hid the tray icon from its own menu. The tray exits at start
     /// while this is set, and the app does not spawn it; Preferences turns it
     /// back on. Defaulted for configs predating the field.
@@ -186,6 +194,24 @@ pub struct AppConfig {
     /// the field.
     #[serde(default)]
     pub local_first: Option<bool>,
+    /// Ask GitHub once a day whether a newer release is out, and say so in the
+    /// desktop app. Off by default: GitHub then sees the address and version
+    /// asking. Never used where a package manager installs updates (see
+    /// [`crate::update::updates_managed`]). Defaulted for configs predating the
+    /// field.
+    #[serde(default)]
+    pub update_check: bool,
+    /// When the update check last asked GitHub, in Unix seconds, so a restart
+    /// does not ask again within [`crate::update::CHECK_INTERVAL`]. Defaulted
+    /// for configs predating the field.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub update_last_checked: Option<i64>,
+    /// The latest release that check found, such as `3.6.0`, so the app can
+    /// say so again after a restart without asking. Older than or equal to the
+    /// running version once the update is installed. Defaulted for configs
+    /// predating the field.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub update_latest: Option<String>,
 }
 
 /// The My Files page's view choices, remembered between runs.
@@ -198,6 +224,10 @@ pub struct FilesView {
     pub descending: bool,
     /// Folders ahead of files, whatever the sort.
     pub folders_first: bool,
+    /// The icon grid's thumbnail edge in logical pixels. `None` means the
+    /// app's default.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub icon_size: Option<i32>,
 }
 
 impl Default for FilesView {
@@ -207,6 +237,57 @@ impl Default for FilesView {
             sort: FileSort::Name,
             descending: false,
             folders_first: true,
+            icon_size: None,
+        }
+    }
+}
+
+/// The Photos page's grid choices, remembered between runs.
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq, Default)]
+#[serde(default)]
+pub struct PhotosView {
+    /// The zoom level: the row height the grid aims for, in logical pixels.
+    /// `None` means the app's default.
+    pub row_height: Option<i32>,
+    /// Crop every photo to a square tile instead of showing it at its own
+    /// shape.
+    pub square: bool,
+}
+
+/// The desktop app's main window, as it was when it last closed.
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq)]
+#[serde(default)]
+pub struct WindowState {
+    /// The unmaximised size, in logical pixels.
+    pub width: i32,
+    pub height: i32,
+    pub maximized: bool,
+}
+
+impl WindowState {
+    /// Below this the saved size is taken for damage and the default is used.
+    pub const MIN_WIDTH: i32 = 480;
+    pub const MIN_HEIGHT: i32 = 400;
+
+    /// This state, with a size too small to use replaced by the default.
+    pub fn usable(self) -> Self {
+        if self.width < Self::MIN_WIDTH || self.height < Self::MIN_HEIGHT {
+            Self {
+                maximized: self.maximized,
+                ..Self::default()
+            }
+        } else {
+            self
+        }
+    }
+}
+
+impl Default for WindowState {
+    fn default() -> Self {
+        Self {
+            width: 980,
+            height: 680,
+            maximized: false,
         }
     }
 }
@@ -310,6 +391,22 @@ impl AppConfig {
     }
 }
 
+/// Fail when the config file at `path` exists but does not parse, so that
+/// [`AppDirs::save_config`] never writes over settings it could not read.
+fn refuse_to_replace_unreadable(path: &Path) -> Result<()> {
+    match std::fs::read_to_string(path) {
+        Ok(content) => match serde_json::from_str::<AppConfig>(&content) {
+            Ok(_) => Ok(()),
+            Err(e) => Err(Error::Other(format!(
+                "{} cannot be read ({e}); fix it or move it aside before changing settings",
+                path.display()
+            ))),
+        },
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
+        Err(e) => Err(e.into()),
+    }
+}
+
 /// Resolved XDG locations for state, cache, and the default mountpoint.
 pub struct AppDirs {
     dirs: ProjectDirs,
@@ -341,6 +438,7 @@ impl AppDirs {
                     // Preserve the original bytes for diagnosis/recovery.  In
                     // particular, never replace a truncated config with defaults
                     // and silently lose mount, device, or ignore settings.
+                    // `save_config` refuses to write over it for the same reason.
                     tracing::error!(path = %path.display(), error = %e, "config is unreadable; using in-memory defaults without overwriting it");
                     return AppConfig::default();
                 }
@@ -348,9 +446,8 @@ impl AppDirs {
         }
 
         let default_config = AppConfig::default();
-        if let Ok(content) = serde_json::to_string_pretty(&default_config) {
-            let _ = std::fs::create_dir_all(self.dirs.config_dir());
-            let _ = std::fs::write(&path, content);
+        if let Err(e) = self.save_config(&default_config) {
+            tracing::warn!(path = %path.display(), error = %e, "could not write the default config");
         }
         default_config
     }
@@ -358,8 +455,15 @@ impl AppDirs {
     /// Persist `config` to [`config_path`](Self::config_path), creating the
     /// config dir if missing. The Settings page calls this after editing the
     /// cache budget or mountpoint; the daemon re-reads the file on its next mount.
+    ///
+    /// Refuses while the file on disk does not parse. Every caller loads,
+    /// changes one field and saves, and [`load_config`](Self::load_config)
+    /// gives defaults for a file it cannot read, so the first change after
+    /// the file was damaged wrote defaults over the mountpoint, the device and
+    /// the ignore rules the user had (`docs/BUGS.md` B223).
     pub fn save_config(&self, config: &AppConfig) -> Result<()> {
         let path = self.config_path();
+        refuse_to_replace_unreadable(&path)?;
         let parent = path
             .parent()
             .ok_or_else(|| Error::Other("configuration path has no parent".into()))?;
@@ -383,6 +487,46 @@ impl AppDirs {
         Ok(())
     }
 
+    /// This machine's id (e.g. ~/.config/proton-drive-linux/machine-id). See
+    /// [`machine_id`](Self::machine_id).
+    pub fn machine_id_path(&self) -> PathBuf {
+        self.dirs.config_dir().join("machine-id")
+    }
+
+    /// A random id for this machine, made on first use and kept in
+    /// [`machine_id_path`](Self::machine_id_path).
+    ///
+    /// It names this machine's profile in a device it may share with other
+    /// computers. Random rather than `/etc/machine-id`, so nothing that
+    /// identifies the host goes to Drive. In a file of its own rather than
+    /// `config.json`, because the app saves the config from a copy it loaded
+    /// earlier, and that would drop an id the daemon had just added.
+    pub fn machine_id(&self) -> Result<String> {
+        let path = self.machine_id_path();
+        match std::fs::read_to_string(&path) {
+            Ok(id) if is_machine_id(id.trim()) => return Ok(id.trim().to_string()),
+            Ok(_) => {
+                tracing::warn!(path = %path.display(), "machine id is unusable; making a new one");
+            }
+            Err(e) if e.kind() == std::io::ErrorKind::NotFound => {}
+            Err(e) => return Err(e.into()),
+        }
+        let mut bytes = [0u8; 16];
+        use std::io::Read as _;
+        std::fs::File::open("/dev/urandom")?.read_exact(&mut bytes)?;
+        let id: String = bytes.iter().map(|b| format!("{b:02x}")).collect();
+        let parent = path
+            .parent()
+            .ok_or_else(|| Error::Other("machine id path has no parent".into()))?;
+        std::fs::create_dir_all(parent)?;
+        let tmp = path.with_extension(format!("tmp-{}", std::process::id()));
+        std::fs::write(&tmp, format!("{id}\n"))?;
+        std::fs::File::open(&tmp)?.sync_all()?;
+        std::fs::rename(&tmp, &path)?;
+        std::fs::File::open(parent)?.sync_all()?;
+        Ok(id)
+    }
+
     /// Persistent state: inode map / cache index DB lives here.
     pub fn state_dir(&self) -> PathBuf {
         // `state_dir` is Linux-only in `directories`; fall back to data dir.
@@ -471,6 +615,12 @@ impl AppDirs {
     }
 }
 
+/// Whether `id` is what [`AppDirs::machine_id`] writes: 32 lowercase hex
+/// digits.
+fn is_machine_id(id: &str) -> bool {
+    id.len() == 32 && id.bytes().all(|b| matches!(b, b'0'..=b'9' | b'a'..=b'f'))
+}
+
 /// Make `dir` owner-only (`0700`). These directories contain decrypted bytes,
 /// plaintext names, and an authenticated control socket, so failure is fatal.
 fn restrict_dir(dir: &Path) -> Result<()> {
@@ -526,6 +676,28 @@ mod tests {
         std::fs::metadata(p).unwrap().permissions().mode() & 0o777
     }
 
+    /// A damaged config must not be replaced by defaults the next time a
+    /// setting changes (`docs/BUGS.md` B223).
+    #[test]
+    fn an_unreadable_config_is_never_written_over() {
+        let dir = std::env::temp_dir().join(format!(
+            "pdfs-cfg-guard-{}-{:?}",
+            std::process::id(),
+            std::thread::current().id()
+        ));
+        let _ = std::fs::remove_dir_all(&dir);
+        std::fs::create_dir_all(&dir).unwrap();
+        let path = dir.join("config.json");
+
+        assert!(refuse_to_replace_unreadable(&path).is_ok(), "no file yet");
+        std::fs::write(&path, serde_json::to_vec(&AppConfig::default()).unwrap()).unwrap();
+        assert!(refuse_to_replace_unreadable(&path).is_ok());
+        std::fs::write(&path, br#"{"mountpoint": "/home/me/Pro"#).unwrap();
+        assert!(refuse_to_replace_unreadable(&path).is_err(), "truncated");
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
     /// `docs/BUGS.md` B6. A permissive mode here is not a cosmetic problem: these
     /// directories hold decrypted content, a plaintext index of every node name,
     /// and the control socket that commands the daemon's session.
@@ -610,11 +782,24 @@ mod tests {
                 sort: FileSort::Modified,
                 descending: true,
                 folders_first: false,
+                icon_size: Some(192),
+            },
+            photos_view: PhotosView {
+                row_height: Some(240),
+                square: true,
+            },
+            window: WindowState {
+                width: 1200,
+                height: 800,
+                maximized: true,
             },
             tray_hidden: true,
             language: Some("de".to_string()),
             online_map: true,
             local_first: Some(false),
+            update_check: true,
+            update_last_checked: Some(1_760_000_000),
+            update_latest: Some("3.6.0".to_string()),
         };
         let json = serde_json::to_string(&config).unwrap();
         let decoded: AppConfig = serde_json::from_str(&json).unwrap();
@@ -626,10 +811,47 @@ mod tests {
         assert_eq!(decoded.proton_theme, Some(true));
         assert!(decoded.tray_hidden);
         assert!(decoded.online_map);
+        assert!(decoded.update_check);
+        assert_eq!(decoded.update_last_checked, Some(1_760_000_000));
+        assert_eq!(decoded.update_latest.as_deref(), Some("3.6.0"));
         assert_eq!(decoded.language.as_deref(), Some("de"));
         assert_eq!(decoded.upload_limit, Some(500_000));
         assert_eq!(decoded.download_limit, None);
         assert_eq!(decoded.files_view, config.files_view);
+        assert_eq!(decoded.photos_view, config.photos_view);
+        assert_eq!(decoded.window, config.window);
+    }
+
+    #[test]
+    fn a_config_without_a_window_opens_at_the_default_size() {
+        let decoded: AppConfig =
+            serde_json::from_str(r#"{"app_version":"a","user_agent":"b"}"#).unwrap();
+        assert_eq!(decoded.window, WindowState::default());
+        let partial: WindowState = serde_json::from_str(r#"{"maximized":true}"#).unwrap();
+        assert_eq!((partial.width, partial.height), (980, 680));
+        assert!(partial.maximized);
+    }
+
+    #[test]
+    fn a_window_saved_too_small_opens_at_the_default_size() {
+        let tiny = WindowState {
+            width: 0,
+            height: 500,
+            maximized: true,
+        };
+        assert_eq!(
+            tiny.usable(),
+            WindowState {
+                maximized: true,
+                ..WindowState::default()
+            }
+        );
+        let fine = WindowState {
+            width: 640,
+            height: 480,
+            maximized: false,
+        };
+        assert_eq!(fine.usable(), fine);
     }
 
     #[test]
@@ -640,6 +862,17 @@ mod tests {
         let partial: FilesView = serde_json::from_str(r#"{"sort":"size"}"#).unwrap();
         assert_eq!(partial.sort, FileSort::Size);
         assert!(partial.folders_first);
+        assert_eq!(partial.icon_size, None);
+    }
+
+    #[test]
+    fn a_config_without_a_photos_view_gets_the_default() {
+        let decoded: AppConfig =
+            serde_json::from_str(r#"{"app_version":"a","user_agent":"b"}"#).unwrap();
+        assert_eq!(decoded.photos_view, PhotosView::default());
+        let partial: PhotosView = serde_json::from_str(r#"{"square":true}"#).unwrap();
+        assert!(partial.square);
+        assert_eq!(partial.row_height, None);
     }
 
     #[test]
@@ -760,6 +993,15 @@ mod tests {
         assert_eq!(decoded.conflict_sweep, Some(SweepMode::Enforce));
     }
 
+    #[test]
+    fn a_machine_id_is_32_lowercase_hex_digits() {
+        assert!(is_machine_id("0123456789abcdef0123456789abcdef"));
+        assert!(!is_machine_id("0123456789ABCDEF0123456789ABCDEF"));
+        assert!(!is_machine_id("0123456789abcdef"));
+        assert!(!is_machine_id("../../../../etc/passwd/0123456789"));
+        assert!(!is_machine_id(""));
+    }
+
     #[test]
     fn a_config_predating_ignore_patterns_still_loads() {
         // Every installed config on disk looks like this; the field must not be

crates/pdfs-core/src/control.rs

@@ -344,6 +344,17 @@ pub enum Request {
     /// or a mirror synced folder), and the move is still made on Proton Drive
     /// without transferring content. Replies with [`Response::Ok`].
     Move { path: String, new_parent: String },
+    /// Copy a file or folder into a folder on Proton Drive, without
+    /// downloading or uploading it. Both `path` and `new_parent` are
+    /// mountpoint-relative, or absolute paths inside My files. A name already
+    /// taken in `new_parent` gets the next free ` (n)` suffix. Replies with
+    /// [`Response::Ok`].
+    Copy { path: String, new_parent: String },
+    /// Ask Proton Drive how much the folder at mountpoint-relative `path`
+    /// holds. Replies with [`Response::FolderSize`].
+    FolderSize { path: String },
+    /// The by-uid twin of [`Request::FolderSize`].
+    FolderSizeByUid { uid: String },
     /// Trash a file or folder. `path` is mountpoint-relative. Replies with
     /// [`Response::Ok`].
     Delete { path: String },
@@ -458,6 +469,13 @@ pub enum Request {
     /// Add a local folder to this machine's device, uploading its tree and
     /// registering the device on first use. Replies with [`Response::Ok`].
     AddSyncFolder { local_path: String },
+    /// Keep a real local directory in step with an existing folder in My files.
+    /// First sync unions one-sided files and preserves differing versions.
+    /// Replies with [`Response::Ok`]; no device backup is created.
+    AttachSyncFolder {
+        local_path: String,
+        remote_path: String,
+    },
     /// List this device's synced folders. Replies with [`Response::SyncFolders`].
     ListSyncFolders,
     /// Remove a synced folder by id; `delete_remote` also trashes its cloud copy.
@@ -469,6 +487,11 @@ pub enum Request {
     /// Pause or resume one mirror folder's reconcile, independent of the
     /// global pause. Persisted until resumed. Replies with [`Response::Ok`].
     SetSyncFolderPaused { id: i64, paused: bool },
+    /// Forget what a mirror folder synced before, so its next pass compares
+    /// both sides afresh: what is on one side only is copied to the other, and
+    /// a file that differs keeps both versions. Nothing is deleted. Replies
+    /// with [`Response::Ok`].
+    ResetSyncFolder { id: i64 },
     /// Force a reconcile pass: one folder by id, or all when `id` is `None`.
     /// Replies with [`Response::Ok`].
     SyncNow { id: Option<i64> },
@@ -596,6 +619,24 @@ pub enum Request {
     RemovePublicLink { path: String, id: String },
     /// The by-uid twin of [`Request::RemovePublicLink`].
     RemovePublicLinkByUid { uid: String, id: String },
+    /// Change the public link `id` on the node at `path`, keeping its URL.
+    /// `role` is "viewer" or "editor", or `None` to keep the current one.
+    /// Replies with [`Response::PublicLink`].
+    UpdatePublicLink {
+        path: String,
+        id: String,
+        role: Option<String>,
+        password: LinkChange<String>,
+        expires: LinkChange<i64>,
+    },
+    /// The by-uid twin of [`Request::UpdatePublicLink`].
+    UpdatePublicLinkByUid {
+        uid: String,
+        id: String,
+        role: Option<String>,
+        password: LinkChange<String>,
+        expires: LinkChange<i64>,
+    },
     /// Stop sharing the node at `path`: remove its public link, every pending
     /// invitation and every member. Each removal is attempted even if an
     /// earlier one fails. Replies with [`Response::Ok`], or an error naming
@@ -951,14 +992,17 @@ impl SyncIssue {
     }
 }
 
-/// One synced local folder on this machine's device (in [`Response::SyncFolders`]).
+/// One device backup or attached My files mirror (in [`Response::SyncFolders`]).
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct SyncFolderInfo {
     /// Row id — the handle for [`Request::RemoveSyncFolder`]/[`Request::SetSyncFolderMode`].
     pub id: i64,
+    /// `device` backup or `attached` My files mirror. Older daemons only had backups.
+    #[serde(default = "default_sync_folder_kind")]
+    pub kind: String,
     /// Absolute local folder path.
     pub local_path: String,
-    /// The uid of the folder's remote root under the device root.
+    /// The uid of the remote root under the device root or My files.
     pub remote_uid: String,
     /// `mirror` (full local copy, two-way synced) or `ondemand` (FUSE mount).
     pub mode: String,
@@ -981,6 +1025,10 @@ pub struct SyncFolderInfo {
     pub paused: bool,
 }
 
+fn default_sync_folder_kind() -> String {
+    "device".into()
+}
+
 /// A folder under this machine's device offered for restore (in
 /// [`Response::RestorableFolders`]).
 #[derive(Serialize, Deserialize, Debug, Clone)]
@@ -1075,6 +1123,18 @@ pub struct PublicLinkInfo {
     pub created: i64,
 }
 
+/// What [`Request::UpdatePublicLink`] does with one option of a link: its
+/// custom password or its expiry.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+pub enum LinkChange<T> {
+    /// Leave the option as it is.
+    Keep,
+    /// Remove the option: no custom password, or no expiry.
+    Remove,
+    /// Set the option to this value.
+    Set(T),
+}
+
 /// One invitation addressed to me (in [`Response::Invitations`]).
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct InvitationInfo {
@@ -1169,6 +1229,7 @@ pub enum ActivityKind {
     Sync,
     Rename,
     Move,
+    Copy,
     CreateFolder,
     Trash,
     Restore,
@@ -1260,8 +1321,15 @@ pub struct DirEntry {
     pub size: u64,
     /// Modification time, epoch seconds.
     pub modified: i64,
-    /// Whether the file is pinned to this device.
+    /// Whether the node is pinned to this device, on its own or through a
+    /// pinned folder above it.
     pub pinned: bool,
+    /// Whether the node is kept on this device because a folder above it is
+    /// pinned. Such a node cannot be unpinned on its own. Set in
+    /// [`Request::ListDir`] listings only. Defaulted for wire-compat with
+    /// daemons predating the field.
+    #[serde(default)]
+    pub pinned_by_folder: bool,
     /// Whether the file's full content is present in the local cache (a current,
     /// non-stale blob). Always false for folders. Defaulted for wire-compat with
     /// clients/daemons predating the field.
@@ -1584,6 +1652,10 @@ pub struct RedateSummary {
     /// name implies)` — what a dry run is read for.
     #[serde(default)]
     pub samples: Vec<(String, i64, i64)>,
+    /// Why the run as a whole failed, when it did. The counts are then
+    /// empty: the run never got to the photos.
+    #[serde(default)]
+    pub error: Option<String>,
 }
 
 /// How a Google Photos Takeout import is going, or how the last one ended
@@ -1613,6 +1685,10 @@ pub struct ImportSummary {
     pub bytes: u64,
     /// True when the run stopped early because it was cancelled.
     pub cancelled: bool,
+    /// Why the run as a whole failed, when it did, such as an archive that
+    /// is not a zip. The counts are then empty.
+    #[serde(default)]
+    pub error: Option<String>,
 }
 
 /// One album in a [`Response::Albums`] listing.
@@ -1716,6 +1792,11 @@ pub struct PhotoItem {
     /// the JPEG it shows is not the whole of what is stored.
     #[serde(default)]
     pub has_raw: bool,
+    /// GeoNames id of the town the photo was taken in, when its location is
+    /// known; [`crate::places::city`] names it. Older daemons omit it, and
+    /// album entries do not carry it.
+    #[serde(default)]
+    pub place_id: Option<u32>,
 }
 
 /// A daemon too old to classify a timeline entry is assumed to have served a
@@ -1775,6 +1856,34 @@ pub fn is_thumbnail_image_name(name: &str) -> bool {
         || RAW_THUMBNAIL_EXTENSIONS.contains(&extension.as_str())
 }
 
+/// The smallest `.ts` file taken for an MPEG transport stream. `.ts` is
+/// TypeScript source as often as it is a recording, and the two sit far apart
+/// in size: a source file is kilobytes, while a second of broadcast video is
+/// already megabytes. Drive often stores either kind as
+/// `application/octet-stream`, so the size is the only signal a listing has.
+pub const TS_VIDEO_MIN_BYTES: u64 = 1024 * 1024;
+
+/// Whether a file named `name`, of `size` bytes when the caller knows it, is a
+/// video. The extension decides, except for `.ts`, which counts as video only
+/// from [`TS_VIDEO_MIN_BYTES`] up. A `.ts` of unknown size counts as video, as
+/// [`PhotoKind::classify`] has it.
+pub fn is_video_file_name(name: &str, size: Option<u64>) -> bool {
+    if PhotoKind::classify(Some(name), None) != PhotoKind::Video {
+        return false;
+    }
+    let transport_stream = name
+        .rsplit_once('.')
+        .is_some_and(|(_, extension)| extension.eq_ignore_ascii_case("ts"));
+    !transport_stream || size.is_none_or(|size| size >= TS_VIDEO_MIN_BYTES)
+}
+
+/// Whether file listings show a thumbnail for a file named `name`, of `size`
+/// bytes when known: an image [`is_thumbnail_image_name`] accepts, or a video,
+/// whose thumbnail is a frame the daemon takes with ffmpeg.
+pub fn is_thumbnail_media_name(name: &str, size: Option<u64>) -> bool {
+    is_thumbnail_image_name(name) || is_video_file_name(name, size)
+}
+
 /// Whether `name` is one of the concrete RAW formats handled by the exiftool
 /// embedded-preview path. Deliberately excludes generic/legacy grab-bags whose
 /// preview availability is not dependable.
@@ -1850,6 +1959,27 @@ pub fn pending_summary(uploads: u64, changes: u64) -> Option<String> {
     }
 }
 
+/// Whether the daemon that reported `version` in a [`Response::Status`] is an
+/// older release than this build. Installing a package replaces the binaries
+/// but leaves the running user service on the old one, which keeps its bugs
+/// until it restarts, while the app and the CLI already describe the new
+/// release (#33). Empty means a daemon from before the field, so older too.
+///
+/// Only older counts. A newer daemon means this front-end is the one still
+/// running from before the upgrade, and restarting the service would not help.
+pub fn daemon_outdated(version: &str) -> bool {
+    fn parse(v: &str) -> Option<(u64, u64, u64)> {
+        let mut parts = v.split('.').map(|p| p.parse().ok());
+        let parsed = (parts.next()??, parts.next()??, parts.next()??);
+        parts.next().is_none().then_some(parsed)
+    }
+    match (parse(version), parse(env!("CARGO_PKG_VERSION"))) {
+        (Some(running), Some(this)) => running < this,
+        (None, _) => version.is_empty(),
+        (Some(_), None) => false,
+    }
+}
+
 /// One worker thread in a [`Diagnostics`] report.
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct WorkerState {
@@ -1897,6 +2027,29 @@ pub struct Diagnostics {
     pub control_handler_limit: usize,
     /// Queued mutations not yet drained.
     pub pending_ops: u64,
+    /// The folder-sync engine. `None` from a daemon that predates the field.
+    #[serde(default)]
+    pub sync: Option<SyncEngineState>,
+}
+
+/// What the folder-sync engine is doing, for [`Diagnostics`].
+///
+/// The engine is one thread that runs every synced folder's passes in turn.
+/// Dead or stuck, it looked exactly like an idle one: workers idle, nothing
+/// queued, nothing in the journal (`docs/BUGS.md` B259).
+#[derive(Serialize, Deserialize, Debug, Clone, Default)]
+pub struct SyncEngineState {
+    /// Whether the engine thread is running. Once it has ended, nothing syncs
+    /// until the daemon restarts.
+    pub running: bool,
+    /// The synced folder whose pass is running, if one is.
+    pub pass_folder: Option<i64>,
+    /// How long that pass has been running.
+    pub pass_age_secs: u64,
+    /// How long since that pass last reported progress.
+    pub pass_idle_secs: u64,
+    /// Passes that ended in a panic since the daemon started.
+    pub panics: u64,
 }
 
 /// The daemon's reply to a [`Request`].
@@ -1969,6 +2122,11 @@ pub enum Response {
         /// out.
         #[serde(default)]
         tokens_unsaved: bool,
+        /// The release of the daemon that answered. A package upgrade does not
+        /// restart the user service, so it can be older than the front-end
+        /// asking; daemons before 3.3.0 omit it, which reads as empty.
+        #[serde(default)]
+        version: String,
     },
     /// A human-readable success message.
     Ok { message: String },
@@ -2144,9 +2302,14 @@ pub enum Response {
         entries: Vec<ShareEntry>,
         link: Option<PublicLinkInfo>,
     },
-    /// A freshly created public link, carrying the shareable URL (reply to
-    /// [`Request::CreatePublicLink`]).
+    /// A freshly created or changed public link, carrying the shareable URL
+    /// (reply to [`Request::CreatePublicLink`] and
+    /// [`Request::UpdatePublicLink`]).
     PublicLink { link: PublicLinkInfo },
+    /// What a folder holds on Proton Drive (reply to [`Request::FolderSize`]):
+    /// the bytes on storage and the number of items below it, folders and
+    /// trashed items included.
+    FolderSize { size: u64, items: u64 },
     /// Invitations addressed to me (reply to [`Request::ListInvitations`]).
     Invitations { items: Vec<InvitationInfo> },
     /// Saved public links (reply to [`Request::ListBookmarks`]).
@@ -2275,9 +2438,17 @@ impl Request {
 ///
 /// Shared by the CLI and GUI so both speak the wire format identically.
 pub fn send(socket: &Path, req: &Request) -> Result<Response> {
+    send_with_timeout(socket, req, req.read_timeout())
+}
+
+/// [`send`] with a caller-chosen limit on how long the daemon may take to
+/// answer, which also bounds the write. For a caller that must never keep a
+/// person waiting, such as shell completion, where a slow answer is worth less
+/// than none.
+pub fn send_with_timeout(socket: &Path, req: &Request, timeout: Duration) -> Result<Response> {
     let mut stream = UnixStream::connect(socket)?;
-    stream.set_read_timeout(Some(req.read_timeout()))?;
-    stream.set_write_timeout(Some(WRITE_TIMEOUT))?;
+    stream.set_read_timeout(Some(timeout))?;
+    stream.set_write_timeout(Some(timeout.min(WRITE_TIMEOUT)))?;
     let mut line = serde_json::to_vec(req)?;
     line.push(b'\n');
     stream.write_all(&line)?;
@@ -2537,6 +2708,41 @@ mod tests {
         assert_eq!(PhotoKind::classify(Some("x.jpg"), Some("video/mp4")), Photo);
     }
 
+    #[test]
+    fn a_ts_file_is_a_video_only_at_the_size_of_one() {
+        const GB: u64 = 1024 * 1024 * 1024;
+        assert!(!is_video_file_name("app.ts", Some(3 * 1024)));
+        assert!(!is_video_file_name(
+            "bundle.TS",
+            Some(TS_VIDEO_MIN_BYTES - 1)
+        ));
+        assert!(is_video_file_name("recording.ts", Some(9 * GB)));
+        assert!(is_video_file_name("recording.TS", Some(TS_VIDEO_MIN_BYTES)));
+        assert!(is_video_file_name("recording.ts", None));
+        // Only `.ts` is in doubt; every other video name is one at any size.
+        assert!(is_video_file_name("clip.mkv", Some(10)));
+        assert!(is_video_file_name("clip.m2ts", Some(10)));
+        assert!(!is_video_file_name("notes.txt", Some(9 * GB)));
+        assert!(!is_video_file_name("ts", Some(9 * GB)));
+    }
+
+    #[test]
+    fn listings_thumbnail_images_and_videos() {
+        assert!(is_thumbnail_media_name("photo.JPG", Some(10)));
+        assert!(is_thumbnail_media_name("camera.nef", None));
+        assert!(is_thumbnail_media_name("clip.mp4", Some(10)));
+        assert!(is_thumbnail_media_name(
+            "recording.ts",
+            Some(64 * 1024 * 1024)
+        ));
+        assert!(!is_thumbnail_media_name("app.ts", Some(2048)));
+        assert!(!is_thumbnail_media_name(
+            "song.flac",
+            Some(64 * 1024 * 1024)
+        ));
+        assert!(!is_thumbnail_media_name("notes.txt", None));
+    }
+
     /// Keep every extension accepted by the shared classifier covered.  Drive
     /// activation uses this classification before it knows whether opening a
     /// file should stream through FUSE or materialise a complete cache entry;
@@ -2612,6 +2818,27 @@ mod tests {
         );
     }
 
+    /// #33: a daemon left running over an upgrade is named as older, also when
+    /// it predates the version field, but a newer one is not, since restarting
+    /// the service cannot bring it closer to this build.
+    #[test]
+    fn only_an_older_daemon_is_outdated() {
+        assert!(!daemon_outdated(env!("CARGO_PKG_VERSION")));
+        assert!(daemon_outdated(""));
+        assert!(daemon_outdated("0.9.9"));
+        assert!(!daemon_outdated("999.0.0"));
+        assert!(!daemon_outdated("not-a-version"));
+        let old: Response = serde_json::from_str(
+            r#"{"Status":{"username":"u","mountpoint":"/m","pinned":0,
+                "used":0,"budget":0,"pins":[]}}"#,
+        )
+        .unwrap();
+        let Response::Status { version, .. } = old else {
+            panic!("not a status: {old:?}");
+        };
+        assert!(daemon_outdated(&version));
+    }
+
     /// The mutation requests must survive a line-delimited JSON round-trip, since
     /// that is exactly how they cross the control socket.
     #[test]
@@ -2625,6 +2852,10 @@ mod tests {
                 path: "a/b.txt".into(),
                 new_parent: "d".into(),
             },
+            Request::Copy {
+                path: "a/b.txt".into(),
+                new_parent: "d".into(),
+            },
             Request::Delete {
                 path: "a/b.txt".into(),
             },
@@ -3096,6 +3327,7 @@ mod tests {
                 id: 3,
                 paused: true,
             },
+            Request::ResetSyncFolder { id: 3 },
             Request::SetBandwidthLimits {
                 upload: 1_000_000,
                 download: 0,
@@ -3185,6 +3417,24 @@ mod tests {
                 uid: "vol~link".into(),
                 id: "url-1".into(),
             },
+            Request::UpdatePublicLink {
+                path: "a/b".into(),
+                id: "url-1".into(),
+                role: Some("editor".into()),
+                password: LinkChange::Set("pw".into()),
+                expires: LinkChange::Remove,
+            },
+            Request::UpdatePublicLinkByUid {
+                uid: "vol~link".into(),
+                id: "url-1".into(),
+                role: None,
+                password: LinkChange::Keep,
+                expires: LinkChange::Set(1_700_000_000),
+            },
+            Request::FolderSize { path: "a".into() },
+            Request::FolderSizeByUid {
+                uid: "vol~link".into(),
+            },
             Request::ListSharedByMe,
             Request::ListActivity { limit: 100 },
             Request::ListSharedWithMe,
@@ -3559,6 +3809,16 @@ mod tests {
                 },
                 "RemovePublicLinkByUid",
             ),
+            (
+                Request::UpdatePublicLinkByUid {
+                    uid: "vol~link".into(),
+                    id: "link".into(),
+                    role: None,
+                    password: LinkChange::Keep,
+                    expires: LinkChange::Keep,
+                },
+                "UpdatePublicLinkByUid",
+            ),
             (
                 Request::StopSharingByUid {
                     uid: "vol~link".into(),
@@ -3584,6 +3844,7 @@ mod tests {
                 | Request::RemoveShareEntryByUid { uid, .. }
                 | Request::CreatePublicLinkByUid { uid, .. }
                 | Request::RemovePublicLinkByUid { uid, .. }
+                | Request::UpdatePublicLinkByUid { uid, .. }
                 | Request::StopSharingByUid { uid } => uid,
                 other => panic!("decoded into the wrong dispatch variant: {other:?}"),
             };
@@ -3592,6 +3853,25 @@ mod tests {
         }
     }
 
+    #[test]
+    fn a_link_update_names_what_it_keeps_removes_and_sets() {
+        let request = Request::UpdatePublicLink {
+            path: "a/b".into(),
+            id: "url-1".into(),
+            role: None,
+            password: LinkChange::Keep,
+            expires: LinkChange::Set(1_700_000_000),
+        };
+        assert_eq!(
+            serde_json::to_string(&request).unwrap(),
+            r#"{"UpdatePublicLink":{"path":"a/b","id":"url-1","role":null,"password":"Keep","expires":{"Set":1700000000}}}"#
+        );
+        assert_eq!(
+            serde_json::to_string(&LinkChange::<String>::Remove).unwrap(),
+            r#""Remove""#
+        );
+    }
+
     #[test]
     fn open_file_accepts_a_request_from_a_client_predating_the_uid_field() {
         let legacy = r#"{"OpenFile":{"path":"Documents/ONBOARDING.md"}}"#;

crates/pdfs-core/src/db/albums.rs

@@ -186,6 +186,8 @@ impl Db {
                     // made, and it shows exactly what they put in it.
                     group_size: 1,
                     has_raw: false,
+                    // Album rows carry no location.
+                    place_id: None,
                 })
             })?
             .collect::<rusqlite::Result<_>>()?;
@@ -247,6 +249,8 @@ impl Db {
                     // made, and it shows exactly what they put in it.
                     group_size: 1,
                     has_raw: false,
+                    // Album rows carry no location.
+                    place_id: None,
                 })
             })?
             .collect::<rusqlite::Result<_>>()?;

crates/pdfs-core/src/db/local.rs

@@ -111,9 +111,80 @@ impl Db {
         )?;
         let count: i64 = tx.query_row("SELECT COUNT(*) FROM local_files", [], |r| r.get(0))?;
         tx.commit()?;
+        drop(conn);
+        self.compact_search_indexes_if_due(finished_at)?;
         Ok(count)
     }
 
+    /// Close a scan that did not see everything: it stopped at the entry cap,
+    /// or a batch failed to write. Nothing is pruned, since a path it missed is
+    /// not a path that is gone; the next complete scan prunes. Returns the
+    /// number of indexed entries.
+    ///
+    /// Pruning after such a scan dropped every entry it had not reached, and
+    /// the next scan put them back. That churn is most of what grew
+    /// `local_fts` to 16 times its size (`docs/BUGS.md` B217).
+    pub fn local_finish_partial_scan(&self, finished_at: i64) -> Result<i64> {
+        let conn = self.conn.lock();
+        conn.execute(
+            "INSERT INTO sync_state (key, value) VALUES ('local_indexed_at', ?1)
+             ON CONFLICT(key) DO UPDATE SET value = excluded.value",
+            [finished_at.to_string()],
+        )?;
+        let count: i64 = conn.query_row("SELECT COUNT(*) FROM local_files", [], |r| r.get(0))?;
+        Ok(count)
+    }
+
+    /// Compact both full-text indexes, at most once a day.
+    ///
+    /// FTS5 keeps a deleted entry's data until the segments holding it are
+    /// merged, and with the few large segments these indexes settle into that
+    /// is close to never. Every file the local scan sees disappear or appear
+    /// leaves some behind, and every node row the tree replaces does too: on
+    /// one machine `local_fts` held 317 MiB for 40,000 paths, against 20 MiB
+    /// rebuilt, and a search took four times as long (`docs/BUGS.md` B217).
+    ///
+    /// `local_fts` is rebuilt from `local_files`, which also drops anything
+    /// left over, and `nodes_fts`, which has no content table to rebuild from,
+    /// is merged into one segment. Each runs in its own transaction on the
+    /// write connection, about half a second on an index that size; once a
+    /// day keeps the leftovers small without paying that at every scan.
+    pub fn compact_search_indexes_if_due(&self, now: i64) -> Result<()> {
+        const EVERY_SECS: i64 = 24 * 60 * 60;
+        let last: i64 = self
+            .read()
+            .query_row(
+                "SELECT value FROM sync_state WHERE key = 'fts_compacted_at'",
+                [],
+                |row| row.get::<_, String>(0),
+            )
+            .optional()?
+            .and_then(|v| v.parse().ok())
+            .unwrap_or(0);
+        if now - last < EVERY_SECS {
+            return Ok(());
+        }
+        let started = std::time::Instant::now();
+        {
+            let conn = self.conn.lock();
+            conn.execute("INSERT INTO local_fts(local_fts) VALUES('rebuild')", [])?;
+        }
+        {
+            let conn = self.conn.lock();
+            conn.execute("INSERT INTO nodes_fts(nodes_fts) VALUES('optimize')", [])?;
+            conn.execute(
+                "INSERT INTO sync_state (key, value) VALUES ('fts_compacted_at', ?1)
+                 ON CONFLICT(key) DO UPDATE SET value = excluded.value",
+                [now.to_string()],
+            )?;
+        }
+        tracing::info!(
+            elapsed_ms = started.elapsed().as_millis() as u64,
+            "compacted the search indexes"
+        );
+        Ok(())
+    }
+
     /// When the last local scan completed (epoch seconds), or `None` if the index
     /// has never been built. The daemon uses this to decide whether a fresh mount
     /// needs an immediate rescan or can serve the existing index.

crates/pdfs-core/src/db/maintenance.rs

@@ -91,8 +91,13 @@ impl Db {
     /// Returns an empty vector when the database is sound; otherwise each entry
     /// is one problem SQLite found. Read-only and safe against a live daemon,
     /// though it reads every page, so it is not free on a large file.
+    ///
+    /// Runs on a read connection: it reads every page, which took 34 s on a
+    /// 567 MiB file, and on the write connection every write in the daemon
+    /// waited that long behind it (`docs/BUGS.md` B218). WAL lets it read a
+    /// consistent snapshot while the writer goes on.
     pub fn integrity_check(&self) -> Result<Vec<String>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare("PRAGMA integrity_check")?;
         let rows = stmt.query_map([], |r| r.get::<_, String>(0))?;
         let mut problems = Vec::new();
@@ -107,9 +112,11 @@ impl Db {
         Ok(problems)
     }
 
-    /// Size and row-count snapshot for `pdfs cache inspect`.
+    /// Size and row-count snapshot for `pdfs cache inspect`. On a read
+    /// connection, for the reason [`integrity_check`](Self::integrity_check)
+    /// gives: counting the rows of every table reads most of the file.
     pub fn stats(&self) -> Result<DbStats> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let page_count: i64 = conn.query_row("PRAGMA page_count", [], |r| r.get(0))?;
         let free_pages: i64 = conn.query_row("PRAGMA freelist_count", [], |r| r.get(0))?;
         let page_size: i64 = conn.query_row("PRAGMA page_size", [], |r| r.get(0))?;
@@ -218,6 +225,40 @@ mod tests {
         assert!(db.integrity_check().unwrap().is_empty());
     }
 
+    /// `pdfs diagnose` and `pdfs cache inspect` read the whole file. Behind the
+    /// write lock they froze every write in the daemon for as long as that
+    /// took (`docs/BUGS.md` B218).
+    #[test]
+    fn the_integrity_check_and_stats_do_not_wait_for_the_writer() {
+        let path = std::env::temp_dir().join(format!(
+            "pdfs-check-{}-{}.db",
+            std::process::id(),
+            std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .unwrap()
+                .as_nanos()
+        ));
+        let db = std::sync::Arc::new(Db::open(&path).unwrap());
+        let writer = db.conn.lock();
+        let (tx, rx) = std::sync::mpsc::channel();
+        let reader = std::sync::Arc::clone(&db);
+        std::thread::spawn(move || {
+            let checked = reader.integrity_check().map(|p| p.is_empty());
+            let counted = reader.stats().map(|s| s.page_count > 0);
+            let _ = tx.send((checked.ok(), counted.ok()));
+        });
+        let answer = rx.recv_timeout(std::time::Duration::from_secs(10));
+        drop(writer);
+        assert_eq!(answer.ok(), Some((Some(true), Some(true))));
+        drop(db);
+        for suffix in ["", "-wal", "-shm"] {
+            let mut file = path.as_os_str().to_owned();
+            file.push(suffix);
+            let _ = std::fs::remove_file(std::path::PathBuf::from(file));
+        }
+        let _ = std::fs::remove_file(path.with_extension("db.lock"));
+    }
+
     #[test]
     fn stats_report_the_schema_and_the_known_tables() {
         let db = Db::open_in_memory().unwrap();

crates/pdfs-core/src/db/migrations.rs

@@ -11,7 +11,7 @@ use super::Db;
 use crate::Result;
 
 /// Current schema version. Bump on every forward migration added below.
-pub(super) const SCHEMA_VERSION: i64 = 42;
+pub(super) const SCHEMA_VERSION: i64 = 45;
 
 impl Db {
     pub(super) fn migrate(&self) -> Result<()> {
@@ -440,6 +440,56 @@ impl Db {
                 tx.execute_batch(MIGRATION_V42)?;
             }
         }
+        if current < 43 {
+            let has_ops: bool = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'pending_op'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            if has_ops {
+                tx.execute_batch(MIGRATION_V43)?;
+            }
+        }
+        if current < 44 {
+            // Same guards as V26-V42.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('sync_entry') \
+                 WHERE name = 'remote_revision_id'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            let has_entries: bool = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'sync_entry'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            if has_entries && !has_column {
+                tx.execute_batch(MIGRATION_V44)?;
+            }
+        }
+        if current < 45 {
+            let has_folders: bool = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'sync_folder'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            let has_kind: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('sync_folder') WHERE name = 'kind'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            if has_folders && !has_kind {
+                tx.execute_batch(MIGRATION_V45_FOLDERS)?;
+                let has_mounts: bool = tx.query_row(
+                    "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'mount'",
+                    [],
+                    |row| row.get::<_, i64>(0),
+                )? > 0;
+                if has_mounts {
+                    tx.execute_batch(MIGRATION_V45_MOUNTS)?;
+                }
+            }
+        }
         tx.execute(
             "INSERT INTO sync_state (key, value) VALUES ('schema_version', ?1)
              ON CONFLICT(key) DO UPDATE SET value = excluded.value",
@@ -1330,3 +1380,82 @@ const MIGRATION_V42: &str = "
 ALTER TABLE pending_op ADD COLUMN sent_sha1 TEXT;
 ALTER TABLE pending_op ADD COLUMN sent_to TEXT;
 ";
+
+/// Schema v43: queued ops by kind and name.
+///
+/// Before each create, rename and trash the drain asks whether a queued trash
+/// or rename holds the name it wants, and a released name wakes the ops
+/// waiting for it. Each of those scanned the whole queue, so a large offline
+/// batch made draining it quadratic. The kind leads, so a lookup of every
+/// queued rename uses the index too.
+const MIGRATION_V43: &str = "
+CREATE INDEX IF NOT EXISTS pending_op_kind_name ON pending_op(kind, name);
+";
+
+/// Schema v44: a synced file's baseline remembers the revision it was synced
+/// at.
+///
+/// A mirrored file edited here is uploaded as a new revision of whatever is
+/// current on Drive, and another computer syncing the same folder may have
+/// committed one since this pass looked. The revision id is what the upload
+/// checks first, so that edit becomes a conflict copy instead of being
+/// replaced (B249). `NULL` means "this row predates the column", and the check
+/// falls back to the modification time and size; each row gains a real value
+/// the next time its path is synced.
+const MIGRATION_V44: &str = "
+ALTER TABLE sync_entry ADD COLUMN remote_revision_id TEXT;
+";
+
+/// Schema v45: distinguish device backups from My files attachments. Existing
+/// released rows are device backups. Attachments cannot evict their local tree.
+const MIGRATION_V45_FOLDERS: &str = "
+ALTER TABLE sync_folder ADD COLUMN kind TEXT NOT NULL DEFAULT 'device'
+  CHECK (kind IN ('device', 'attached'));
+CREATE TRIGGER sync_folder_attached_insert
+BEFORE INSERT ON sync_folder
+WHEN NEW.kind = 'attached' AND (NEW.mode != 'mirror' OR NEW.pending_mode IS NOT NULL)
+BEGIN SELECT RAISE(ABORT, 'attached folders only support mirror mode'); END;
+CREATE TRIGGER sync_folder_attached_update
+BEFORE UPDATE ON sync_folder
+WHEN NEW.kind = 'attached' AND (NEW.mode != 'mirror' OR NEW.pending_mode IS NOT NULL)
+BEGIN SELECT RAISE(ABORT, 'attached folders only support mirror mode'); END;
+";
+
+const MIGRATION_V45_MOUNTS: &str = "
+DROP TRIGGER mount_sync_folder_insert;
+DROP INDEX mount_myfiles;
+DROP INDEX mount_device;
+DROP INDEX mount_shared;
+ALTER TABLE mount RENAME TO mount_v44;
+CREATE TABLE mount (
+  id INTEGER PRIMARY KEY,
+  kind TEXT NOT NULL CHECK (kind IN ('myfiles', 'device', 'attached', 'shared')),
+  sync_folder_id INTEGER REFERENCES sync_folder(id) ON DELETE CASCADE,
+  share_root_uid TEXT,
+  local_path TEXT NOT NULL DEFAULT '',
+  root_uid TEXT NOT NULL DEFAULT '',
+  root_share_id TEXT NOT NULL DEFAULT '',
+  mode TEXT NOT NULL DEFAULT 'unknown',
+  access TEXT NOT NULL DEFAULT 'rw' CHECK (access IN ('rw', 'ro')),
+  CHECK (
+    (kind = 'myfiles' AND sync_folder_id IS NULL AND share_root_uid IS NULL)
+    OR (kind IN ('device', 'attached') AND sync_folder_id IS NOT NULL AND share_root_uid IS NULL)
+    OR (kind = 'shared' AND sync_folder_id IS NULL AND share_root_uid IS NOT NULL)
+  )
+);
+INSERT INTO mount SELECT * FROM mount_v44;
+DROP TABLE mount_v44;
+CREATE UNIQUE INDEX mount_myfiles ON mount(kind) WHERE kind = 'myfiles';
+CREATE UNIQUE INDEX mount_device ON mount(sync_folder_id) WHERE kind IN ('device', 'attached');
+CREATE UNIQUE INDEX mount_shared ON mount(share_root_uid) WHERE kind = 'shared';
+CREATE TRIGGER mount_sync_folder_insert
+AFTER INSERT ON sync_folder
+BEGIN
+  INSERT INTO mount (kind, sync_folder_id) VALUES (NEW.kind, NEW.id);
+END;
+CREATE TRIGGER mount_sync_folder_kind_update
+AFTER UPDATE OF kind ON sync_folder
+BEGIN
+  UPDATE mount SET kind = NEW.kind WHERE sync_folder_id = NEW.id;
+END;
+";

crates/pdfs-core/src/db/mod.rs

@@ -179,6 +179,45 @@ impl Drop for Reader<'_> {
     }
 }
 
+/// The write connection with `synchronous=FULL`, back to NORMAL on drop.
+///
+/// NORMAL in WAL mode keeps a commit across a crash of the process but not
+/// across a power loss: the WAL is synced only at checkpoints. That is fine for
+/// metadata the next listing re-fetches, and not for the queue. A staged blob
+/// is synced before its op is queued, and the op row is what makes it
+/// reachable; losing that row loses a write `close()` already reported as
+/// done. A FULL commit syncs the WAL, which covers every NORMAL commit before
+/// it as well.
+pub(super) struct Durable<'a>(parking_lot::MutexGuard<'a, Connection>);
+
+impl<'a> Durable<'a> {
+    pub(super) fn new(conn: parking_lot::MutexGuard<'a, Connection>) -> Result<Self> {
+        conn.pragma_update(None, "synchronous", "FULL")?;
+        Ok(Self(conn))
+    }
+}
+
+impl std::ops::Deref for Durable<'_> {
+    type Target = Connection;
+
+    fn deref(&self) -> &Connection {
+        &self.0
+    }
+}
+
+impl std::ops::DerefMut for Durable<'_> {
+    fn deref_mut(&mut self) -> &mut Connection {
+        &mut self.0
+    }
+}
+
+impl Drop for Durable<'_> {
+    fn drop(&mut self) {
+        // A failure leaves the writer at FULL: slower, never less safe.
+        let _ = self.0.pragma_update(None, "synchronous", "NORMAL");
+    }
+}
+
 /// Open a second connection to the same file for reads only.
 ///
 /// `SQLITE_OPEN_READ_ONLY` plus `query_only` is belt and braces: the flag stops
@@ -216,18 +255,34 @@ impl Db {
         let conn = match Self::open_configured(path) {
             Ok(conn) => conn,
             Err(e) if is_corrupt(&e) => {
-                // Every byte in here is derived from the account or from the
-                // content cache directory, so the recovery is to start over —
-                // loudly, and keeping the damaged file for a post-mortem rather
-                // than deleting evidence.
+                // Most of what is in here is derived from the account and is
+                // fetched again. The queue is not: it holds writes accepted
+                // here that Drive does not have yet, and the mirror baselines
+                // and pins are this machine's alone. So the damaged file is
+                // moved aside, kept as evidence, and those tables are copied
+                // out of it into the new one as far as SQLite can still read
+                // them (`docs/BUGS.md` B216).
                 tracing::error!(
                     db = %path.display(),
                     error = %e,
-                    "cache database is corrupt — moving it aside and rebuilding \
-                     (metadata will be re-fetched; no user data is stored here)"
+                    "cache database is corrupt; moving it aside, rebuilding, and \
+                     copying the upload queue, sync baselines and pins out of it"
                 );
-                quarantine_corrupt_db(path)?;
-                Self::open_configured(path)?
+                let damaged = quarantine_corrupt_db(path)?;
+                let conn = Self::open_configured(path)?;
+                for (table, result) in salvage(&conn, &damaged) {
+                    match result {
+                        Ok(rows) => {
+                            tracing::warn!(table, rows, "salvaged from the damaged database")
+                        }
+                        Err(error) => tracing::error!(
+                            table,
+                            %error,
+                            "could not salvage from the damaged database"
+                        ),
+                    }
+                }
+                conn
             }
             Err(e) => return Err(e),
         };
@@ -254,6 +309,12 @@ impl Db {
         Ok(db)
     }
 
+    /// The write connection for a commit that accepts a user's change into
+    /// the queue. See [`Durable`].
+    pub(super) fn durable(&self) -> Result<Durable<'_>> {
+        Durable::new(self.conn.lock())
+    }
+
     /// A connection for a `SELECT`-only method.
     ///
     /// Reads see the last committed state, which is the same thing they saw
@@ -281,7 +342,8 @@ impl Db {
     fn open_configured(path: &Path) -> Result<Connection> {
         let conn = Connection::open(path)?;
         // WAL: readers never block the single writer. NORMAL sync is the
-        // standard durability/throughput tradeoff for WAL.
+        // standard durability/throughput tradeoff for WAL; the queue commits
+        // that need more raise it to FULL for themselves (`Durable`).
         conn.pragma_update(None, "journal_mode", "WAL")?;
         conn.pragma_update(None, "synchronous", "NORMAL")?;
         conn.pragma_update(None, "foreign_keys", "ON")?;
@@ -428,12 +490,96 @@ fn is_corrupt(e: &Error) -> bool {
     )
 }
 
-/// Move a damaged database (and its WAL sidecars) out of the way so the next
-/// open starts from empty.
+/// The tables [`salvage`] copies out of a damaged database, in order, each
+/// with the rows it keeps.
 ///
-/// Renamed rather than deleted: this is a cache, but it is also the only
-/// evidence of what went wrong, and it costs one file the user can remove.
-fn quarantine_corrupt_db(path: &Path) -> Result<()> {
+/// The queue goes with the node rows it names by local id: a create made here
+/// has no other record of its node, and a real node keeps its local id when its
+/// folder is listed again. Those rows come back unlisted, so their folders are
+/// fetched again rather than trusted. Claims are cleared by [`Db::open`] as
+/// after any other crash.
+const SALVAGE: &[(&str, &str)] = &[
+    (
+        "nodes",
+        "lid IN (SELECT lid FROM old.pending_op WHERE lid IS NOT NULL
+                 UNION SELECT parent_lid FROM old.pending_op WHERE parent_lid IS NOT NULL)
+         OR uid LIKE 'local~%'",
+    ),
+    ("pending_op", "1"),
+    ("sync_folder", "1"),
+    ("sync_entry", "1"),
+    ("pins", "1"),
+    ("own_sealed_rev", "1"),
+];
+
+/// Copy what only this machine has out of the damaged database at `damaged`
+/// into the fresh one `conn` just created. Returns how each table went.
+///
+/// Each table is copied in its own transaction, so a table SQLite cannot read
+/// to the end is left out whole rather than half copied, and does not stop
+/// the others. Only the columns both files have are copied, which covers a
+/// file that broke in the middle of an upgrade. The damaged file is opened read
+/// only and left as it was.
+fn salvage(conn: &Connection, damaged: &Path) -> Vec<(&'static str, Result<usize>)> {
+    let uri = format!(
+        "file:{}?mode=ro",
+        damaged
+            .to_string_lossy()
+            .replace('%', "%25")
+            .replace('?', "%3f")
+            .replace('#', "%23")
+    );
+    if let Err(e) = conn.execute("ATTACH DATABASE ?1 AS old", [&uri]) {
+        let e = Error::Db(e);
+        tracing::error!(error = %e, "could not open the damaged database to salvage it");
+        return Vec::new();
+    }
+    let results = SALVAGE
+        .iter()
+        .map(|&(table, rows)| (table, salvage_table(conn, table, rows)))
+        .collect();
+    let _ = conn.execute("UPDATE nodes SET listed = 0", []);
+    if let Err(e) = conn.execute("DETACH DATABASE old", []) {
+        tracing::warn!(error = %e, "could not detach the damaged database");
+    }
+    results
+}
+
+fn salvage_table(conn: &Connection, table: &str, rows: &str) -> Result<usize> {
+    let columns = |schema: &str| -> Result<Vec<String>> {
+        let mut stmt = conn.prepare(&format!("PRAGMA {schema}.table_info({table})"))?;
+        let names = stmt
+            .query_map([], |r| r.get::<_, String>(1))?
+            .collect::<rusqlite::Result<Vec<_>>>()?;
+        Ok(names)
+    };
+    let new = columns("main")?;
+    let shared: Vec<String> = columns("old")?
+        .into_iter()
+        .filter(|c| new.contains(c))
+        .map(|c| format!("\"{c}\""))
+        .collect();
+    if shared.is_empty() {
+        return Ok(0);
+    }
+    let shared = shared.join(", ");
+    let tx = conn.unchecked_transaction()?;
+    let copied = tx.execute(
+        &format!(
+            "INSERT OR IGNORE INTO main.{table} ({shared}) SELECT {shared} FROM old.{table} WHERE {rows}"
+        ),
+        [],
+    )?;
+    tx.commit()?;
+    Ok(copied)
+}
+
+/// Move a damaged database (and its WAL sidecars) out of the way so the next
+/// open starts from empty. Returns where the database itself went.
+///
+/// Renamed rather than deleted: it is the only evidence of what went wrong,
+/// and [`salvage`] reads what only this machine has back out of it.
+fn quarantine_corrupt_db(path: &Path) -> Result<PathBuf> {
     let stamp = std::time::SystemTime::now()
         .duration_since(std::time::UNIX_EPOCH)
         .map(|d| d.as_secs())
@@ -457,7 +603,9 @@ fn quarantine_corrupt_db(path: &Path) -> Result<()> {
             Err(e) => tracing::warn!(file = %from.display(), error = %e, "could not quarantine"),
         }
     }
-    Ok(())
+    let mut kept = path.as_os_str().to_owned();
+    kept.push(format!(".corrupt-{stamp}"));
+    Ok(PathBuf::from(kept))
 }
 
 #[cfg(test)]

crates/pdfs-core/src/db/mounts.rs

@@ -1,6 +1,6 @@
 //! Unified mount/location presentation rows.
 //!
-//! A device row stores only its `sync_folder` identity. Its path, remote root,
+//! A device or attached row stores only its `sync_folder` identity. Its path, remote root,
 //! mode, state, pending mode, and last-sync timestamp are selected from
 //! `sync_folder`, which remains the authoritative sync-engine table.
 
@@ -72,7 +72,7 @@ impl Db {
         )? > 0)
     }
 
-    /// Every local location, with device fields joined from `sync_folder`.
+    /// Every local location, with synced-folder fields joined from `sync_folder`.
     pub fn mount_list(&self) -> Result<Vec<MountSpec>> {
         let conn = self.read();
         let mut stmt = conn.prepare(
@@ -81,14 +81,14 @@ impl Db {
                  m.kind,
                  m.sync_folder_id,
                  m.share_root_uid,
-                 CASE WHEN m.kind = 'device' THEN sf.local_path ELSE m.local_path END,
-                 CASE WHEN m.kind = 'device' THEN sf.remote_uid ELSE m.root_uid END,
-                 CASE WHEN m.kind = 'device' THEN sf.remote_share_id ELSE m.root_share_id END,
-                 CASE WHEN m.kind = 'device' THEN sf.mode ELSE m.mode END,
+                 CASE WHEN m.kind IN ('device', 'attached') THEN sf.local_path ELSE m.local_path END,
+                 CASE WHEN m.kind IN ('device', 'attached') THEN sf.remote_uid ELSE m.root_uid END,
+                 CASE WHEN m.kind IN ('device', 'attached') THEN sf.remote_share_id ELSE m.root_share_id END,
+                 CASE WHEN m.kind IN ('device', 'attached') THEN sf.mode ELSE m.mode END,
                  m.access,
-                 CASE WHEN m.kind = 'device' THEN sf.state ELSE 'idle' END,
-                 CASE WHEN m.kind = 'device' THEN sf.last_sync ELSE 0 END,
-                 CASE WHEN m.kind = 'device' THEN sf.pending_mode ELSE NULL END
+                 CASE WHEN m.kind IN ('device', 'attached') THEN sf.state ELSE 'idle' END,
+                 CASE WHEN m.kind IN ('device', 'attached') THEN sf.last_sync ELSE 0 END,
+                 CASE WHEN m.kind IN ('device', 'attached') THEN sf.pending_mode ELSE NULL END
                FROM mount AS m
                LEFT JOIN sync_folder AS sf ON sf.id = m.sync_folder_id
               ORDER BY CASE m.kind
@@ -138,6 +138,11 @@ impl Db {
                         Error::Other(format!("mount row {id} has no sync_folder_id"))
                     })?,
                 },
+                "attached" => MountKind::Attached {
+                    sync_folder_id: sync_folder_id.ok_or_else(|| {
+                        Error::Other(format!("mount row {id} has no sync_folder_id"))
+                    })?,
+                },
                 "shared" => MountKind::Shared {
                     share_root_uid: share_root_uid.ok_or_else(|| {
                         Error::Other(format!("mount row {id} has no share_root_uid"))

crates/pdfs-core/src/db/ops.rs

@@ -279,6 +279,45 @@ fn claimable() -> String {
 /// drain replaces it with the uid the server assigns.
 pub const LOCAL_VOLUME: &str = "local";
 
+/// One place a queued create was sent, with when it first was.
+struct SentTarget {
+    parent: String,
+    name: String,
+    at_ms: Option<i64>,
+}
+
+/// The `sent_to` column: `[[parent, name, at_ms], …]`, or `[[parent, name], …]`
+/// as written before the time was kept. `None` when it does not parse.
+fn parse_sent_to(json: Option<&str>) -> Option<Vec<SentTarget>> {
+    #[derive(Deserialize)]
+    #[serde(untagged)]
+    enum Entry {
+        At(String, String, i64),
+        Bare(String, String),
+    }
+    let Some(json) = json else {
+        return Some(Vec::new());
+    };
+    let entries: Vec<Entry> = serde_json::from_str(json).ok()?;
+    Some(
+        entries
+            .into_iter()
+            .map(|entry| match entry {
+                Entry::At(parent, name, at) => SentTarget {
+                    parent,
+                    name,
+                    at_ms: Some(at),
+                },
+                Entry::Bare(parent, name) => SentTarget {
+                    parent,
+                    name,
+                    at_ms: None,
+                },
+            })
+            .collect(),
+    )
+}
+
 /// The uid a node made on this machine goes by until Drive gives it one: its
 /// row's local id under [`LOCAL_VOLUME`].
 ///
@@ -541,7 +580,7 @@ impl Db {
     /// land in the order they were made (`docs/BUGS.md` B141). Should it fail,
     /// [`Db::record_op_failure`] or [`Db::release_op_claim`] drops it.
     pub fn enqueue_op(&self, op: &PendingOp) -> Result<(i64, Option<String>)> {
-        let mut conn = self.conn.lock();
+        let mut conn = self.durable()?;
         let tx = conn.transaction()?;
         let superseded: Option<String> = if op_supersedes(&op.kind) {
             let lid = node_lid(&tx, &op.uid)?;
@@ -598,7 +637,7 @@ impl Db {
         name: &str,
         created_at: i64,
     ) -> Result<(i64, Vec<String>)> {
-        let mut conn = self.conn.lock();
+        let mut conn = self.durable()?;
         let tx = conn.transaction()?;
         let blobs = drop_doomed_ops(&tx, uid)?;
         tx.execute(
@@ -628,7 +667,7 @@ impl Db {
         blob_path: &str,
         meta_json: &str,
     ) -> Result<Option<AttachedBlob>> {
-        let conn = self.conn.lock();
+        let conn = self.durable()?;
         let lid = node_lid(&conn, uid)?;
         let existing: Option<(i64, Option<String>)> = conn
             .query_row(
@@ -691,7 +730,7 @@ impl Db {
         rewrite: impl FnOnce(&str) -> Option<String>,
     ) -> Result<CreateRetired> {
         let (local, real) = (landing.local, landing.real);
-        let mut conn = self.conn.lock();
+        let mut conn = self.durable()?;
         let tx = conn.transaction()?;
         let row: Option<CreateRow> = tx
             .query_row(
@@ -808,12 +847,19 @@ impl Db {
         Ok(())
     }
 
-    /// Record that queued create `id` is being sent to `parent` under `name`.
+    /// Record that queued create `id` is being sent to `parent` under `name`
+    /// at `at_ms`.
     ///
     /// A rename while the op waits rewrites its target, but the file a lost
     /// answer left stays where it was sent. The retry and the trash look
-    /// there too (`docs/BUGS.md` B184).
-    pub fn note_create_target(&self, id: i64, parent: &str, name: &str) -> Result<()> {
+    /// there too (`docs/BUGS.md` B184). A target sent before keeps its first
+    /// time.
+    ///
+    /// A record that does not parse is left as it is rather than replaced
+    /// with this one target: the earlier ones are what the duplicate checks
+    /// look for. Without them a lost answer forks a conflict copy, which
+    /// loses nothing.
+    pub fn note_create_target(&self, id: i64, parent: &str, name: &str, at_ms: i64) -> Result<()> {
         let mut conn = self.conn.lock();
         let tx = conn.transaction()?;
         let sent: Option<String> = tx
@@ -822,15 +868,26 @@ impl Db {
             })
             .optional()?
             .flatten();
-        let mut targets: Vec<(String, String)> = sent
-            .and_then(|json| serde_json::from_str(&json).ok())
-            .unwrap_or_default();
-        let target = (parent.to_string(), name.to_string());
-        if !targets.contains(&target) {
-            targets.push(target);
+        let Some(mut targets) = parse_sent_to(sent.as_deref()) else {
+            tracing::warn!(
+                id,
+                "a queued create's send record does not parse; keeping it"
+            );
+            return Ok(());
+        };
+        if !targets.iter().any(|t| t.parent == parent && t.name == name) {
+            targets.push(SentTarget {
+                parent: parent.to_string(),
+                name: name.to_string(),
+                at_ms: Some(at_ms),
+            });
+            let json: Vec<(&str, &str, i64)> = targets
+                .iter()
+                .map(|t| (t.parent.as_str(), t.name.as_str(), t.at_ms.unwrap_or(0)))
+                .collect();
             tx.execute(
                 "UPDATE pending_op SET sent_to = ?2 WHERE id = ?1",
-                params![id, serde_json::to_string(&targets)?],
+                params![id, serde_json::to_string(&json)?],
             )?;
         }
         tx.commit()?;
@@ -840,6 +897,24 @@ impl Db {
     /// The parent and name queued op `id` was sent under as a create, in the
     /// order it was ([`Db::note_create_target`]).
     pub fn create_targets(&self, id: i64) -> Result<Vec<(String, String)>> {
+        Ok(self
+            .sent_targets(id)?
+            .into_iter()
+            .map(|t| (t.parent, t.name))
+            .collect())
+    }
+
+    /// When queued create `id` was first sent, if that was recorded. Rows
+    /// written before the time was kept have none.
+    pub fn create_first_sent(&self, id: i64) -> Result<Option<i64>> {
+        Ok(self
+            .sent_targets(id)?
+            .into_iter()
+            .filter_map(|t| t.at_ms.filter(|&at| at > 0))
+            .min())
+    }
+
+    fn sent_targets(&self, id: i64) -> Result<Vec<SentTarget>> {
         let sent: Option<String> = self
             .conn
             .lock()
@@ -848,9 +923,7 @@ impl Db {
             })
             .optional()?
             .flatten();
-        Ok(sent
-            .and_then(|json| serde_json::from_str(&json).ok())
-            .unwrap_or_default())
+        Ok(parse_sent_to(sent.as_deref()).unwrap_or_default())
     }
 
     /// The SHA-1 of each blob queued op `id` sent as a create
@@ -898,6 +971,27 @@ impl Db {
         Ok(n > 0)
     }
 
+    /// Replace the sidecar of op `id`, but only while it still holds the blob
+    /// at `blob_path`.
+    ///
+    /// The drain fills an incomplete blob in place and then records it as
+    /// whole, so a retry after a lost answer can recognise its own bytes on the
+    /// server. A write that closed meanwhile has pointed the row at a newer
+    /// blob with its own sidecar; that one must not be overwritten. Returns
+    /// false when the row is gone or holds another blob.
+    pub fn update_op_meta_for_blob(
+        &self,
+        id: i64,
+        blob_path: &str,
+        meta_json: &str,
+    ) -> Result<bool> {
+        let n = self.conn.lock().execute(
+            "UPDATE pending_op SET meta_json = ?3 WHERE id = ?1 AND blob_path = ?2",
+            params![id, blob_path, meta_json],
+        )?;
+        Ok(n > 0)
+    }
+
     /// Point a queued create at a new parent and name, for a node renamed or
     /// moved before it ever reached the server.
     ///
@@ -911,7 +1005,7 @@ impl Db {
     /// name it no longer wants, such as one held by a queued change. A parked
     /// create stays parked.
     pub fn rewrite_op_target(&self, uid: &str, parent_uid: &str, name: &str) -> Result<bool> {
-        let conn = self.conn.lock();
+        let conn = self.durable()?;
         let lid = node_lid(&conn, uid)?;
         let parent_lid = node_lid(&conn, parent_uid)?;
         let n = conn.execute(
@@ -1389,12 +1483,26 @@ impl Db {
     }
 
     /// [`retry_op_now`](Self::retry_op_now) for every op that has failed at
-    /// least once. Returns how many rows changed.
+    /// least once, for the user's "Retry all". Returns how many rows changed.
     pub fn retry_failed_ops_now(&self, now: i64) -> Result<usize> {
+        self.retry_ops_now(now, "")
+    }
+
+    /// [`retry_failed_ops_now`](Self::retry_failed_ops_now) for the ops Drive
+    /// did not refuse, for a reconnect. A link coming back changes nothing
+    /// about a full quota or a missing permission, so those keep their backoff
+    /// instead of all being sent again at once.
+    pub fn retry_unrefused_ops_now(&self, now: i64) -> Result<usize> {
+        self.retry_ops_now(now, "AND issue IS NULL")
+    }
+
+    fn retry_ops_now(&self, now: i64, filter: &str) -> Result<usize> {
         let conn = self.conn.lock();
         let changed = conn.execute(
-            "UPDATE pending_op SET next_attempt_at = ?1
-             WHERE attempts > 0 AND next_attempt_at > ?1 AND next_attempt_at < ?2",
+            &format!(
+                "UPDATE pending_op SET next_attempt_at = ?1
+                 WHERE attempts > 0 AND next_attempt_at > ?1 AND next_attempt_at < ?2 {filter}"
+            ),
             params![now, PARK_UNTIL],
         )?;
         Ok(changed)

crates/pdfs-core/src/db/photos.rs

@@ -40,6 +40,8 @@ pub struct StoredPhoto {
     /// Whether any member of the group is a camera raw file. The grid badges
     /// that, because the JPEG it shows is not the whole of what is stored.
     pub has_raw: bool,
+    /// The town the photo was taken in, once its location has been read.
+    pub place_id: Option<u32>,
 }
 
 /// A town photos were taken in: its GeoNames id (see [`crate::places`]), how
@@ -256,7 +258,7 @@ fn group_photos(entries: &[Grouped]) -> Vec<String> {
 /// own group: the column is `NULL` until the next refresh computes it, and a
 /// `NULL` would otherwise match nothing and drop the photo off the page.
 const PHOTO_SELECT: &str = "SELECT p.uid, p.capture_time, p.name, p.ratio, p.thumb_state, \
-     p.kind, p.favorite, g.n, g.raw \
+     p.kind, p.favorite, g.n, g.raw, p.place_id \
      FROM photos p JOIN (SELECT COALESCE(group_key, uid) AS k, COUNT(*) AS n, \
      MAX(kind = 2) AS raw FROM photos GROUP BY k) g ON g.k = COALESCE(p.group_key, p.uid)";
 
@@ -272,6 +274,7 @@ fn stored_photo(r: &rusqlite::Row<'_>) -> rusqlite::Result<StoredPhoto> {
         favorite: r.get::<_, i64>(6)? != 0,
         group_size: r.get::<_, i64>(7)?.max(1) as usize,
         has_raw: r.get::<_, i64>(8)? != 0,
+        place_id: r.get(9)?,
     })
 }
 

crates/pdfs-core/src/db/sync.rs

@@ -9,6 +9,8 @@ use std::collections::HashMap;
 
 pub struct StoredSyncFolder {
     pub id: i64,
+    /// `device` backup or `attached` My files mirror.
+    pub kind: String,
     pub local_path: String,
     pub remote_uid: String,
     pub remote_share_id: String,
@@ -45,6 +47,12 @@ pub struct StoredSyncEntry {
     pub local_mtime_ns: Option<i64>,
     pub remote_rev: Option<String>,
     pub remote_hash: Option<String>,
+    /// The id of the remote revision this row was synced at. A mirror upload
+    /// checks it before it supersedes what Drive holds, because another client
+    /// may have committed a revision since (`docs/BUGS.md` B249). `None` on a
+    /// row written before schema 44, or by a pass that did not learn it; the
+    /// check then falls back to `remote_rev` and `remote_hash`.
+    pub remote_revision_id: Option<String>,
 }
 
 impl Db {
@@ -53,12 +61,32 @@ impl Db {
         local_path: &str,
         remote_uid: &str,
         remote_share_id: &str,
+    ) -> Result<i64> {
+        self.sync_folder_insert(local_path, remote_uid, remote_share_id, "device")
+    }
+
+    /// Attach an existing My files folder, without creating a device backup.
+    pub fn sync_folder_attach(
+        &self,
+        local_path: &str,
+        remote_uid: &str,
+        remote_share_id: &str,
+    ) -> Result<i64> {
+        self.sync_folder_insert(local_path, remote_uid, remote_share_id, "attached")
+    }
+
+    fn sync_folder_insert(
+        &self,
+        local_path: &str,
+        remote_uid: &str,
+        remote_share_id: &str,
+        kind: &str,
     ) -> Result<i64> {
         let conn = self.conn.lock();
         conn.execute(
-            "INSERT INTO sync_folder (local_path, remote_uid, remote_share_id)
-             VALUES (?1, ?2, ?3)",
-            params![local_path, remote_uid, remote_share_id],
+            "INSERT INTO sync_folder (local_path, remote_uid, remote_share_id, kind)
+             VALUES (?1, ?2, ?3, ?4)",
+            params![local_path, remote_uid, remote_share_id, kind],
         )?;
         Ok(conn.last_insert_rowid())
     }
@@ -67,7 +95,7 @@ impl Db {
     pub fn sync_folder_list(&self) -> Result<Vec<StoredSyncFolder>> {
         let conn = self.read();
         let mut stmt = conn.prepare(
-            "SELECT id, local_path, remote_uid, remote_share_id, mode, pending_mode, state, last_sync
+            "SELECT id, local_path, remote_uid, remote_share_id, mode, pending_mode, state, last_sync, kind
              FROM sync_folder ORDER BY id",
         )?;
         let rows = stmt.query_map([], |r| {
@@ -80,6 +108,7 @@ impl Db {
                 pending_mode: r.get(5)?,
                 state: r.get(6)?,
                 last_sync: r.get(7)?,
+                kind: r.get(8)?,
             })
         })?;
         let mut items = Vec::new();
@@ -93,7 +122,7 @@ impl Db {
     pub fn sync_folder_get(&self, id: i64) -> Result<Option<StoredSyncFolder>> {
         let conn = self.read();
         conn.query_row(
-            "SELECT id, local_path, remote_uid, remote_share_id, mode, pending_mode, state, last_sync
+            "SELECT id, local_path, remote_uid, remote_share_id, mode, pending_mode, state, last_sync, kind
              FROM sync_folder WHERE id = ?1",
             params![id],
             |r| {
@@ -106,6 +135,7 @@ impl Db {
                     pending_mode: r.get(5)?,
                     state: r.get(6)?,
                     last_sync: r.get(7)?,
+                    kind: r.get(8)?,
                 })
             },
         )
@@ -188,7 +218,7 @@ impl Db {
         let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT rel_path, remote_uid, local_mtime, local_size, remote_rev, remote_hash,
-                    local_mtime_ns
+                    local_mtime_ns, remote_revision_id
              FROM sync_entry WHERE folder_id = ?1",
         )?;
         let rows = stmt.query_map(params![folder_id], |r| {
@@ -200,6 +230,7 @@ impl Db {
                 remote_rev: r.get(4)?,
                 remote_hash: r.get(5)?,
                 local_mtime_ns: r.get(6)?,
+                remote_revision_id: r.get(7)?,
             })
         })?;
         let mut map = HashMap::new();
@@ -238,15 +269,16 @@ impl Db {
         conn.execute(
             "INSERT INTO sync_entry
                (folder_id, rel_path, remote_uid, local_mtime, local_size, remote_rev,
-                remote_hash, local_mtime_ns)
-             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)
+                remote_hash, local_mtime_ns, remote_revision_id)
+             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9)
              ON CONFLICT(folder_id, rel_path) DO UPDATE SET
-               remote_uid     = excluded.remote_uid,
-               local_mtime    = excluded.local_mtime,
-               local_size     = excluded.local_size,
-               remote_rev     = excluded.remote_rev,
-               remote_hash    = excluded.remote_hash,
-               local_mtime_ns = excluded.local_mtime_ns",
+               remote_uid         = excluded.remote_uid,
+               local_mtime        = excluded.local_mtime,
+               local_size         = excluded.local_size,
+               remote_rev         = excluded.remote_rev,
+               remote_hash        = excluded.remote_hash,
+               local_mtime_ns     = excluded.local_mtime_ns,
+               remote_revision_id = excluded.remote_revision_id",
             params![
                 folder_id,
                 e.rel_path,
@@ -256,6 +288,7 @@ impl Db {
                 e.remote_rev,
                 e.remote_hash,
                 e.local_mtime_ns,
+                e.remote_revision_id,
             ],
         )?;
         Ok(())
@@ -306,7 +339,7 @@ impl Db {
         {
             let mut select = tx.prepare(
                 "SELECT rel_path, remote_uid, local_mtime, local_size, remote_rev, remote_hash,
-                        local_mtime_ns
+                        local_mtime_ns, remote_revision_id
                    FROM sync_entry
                   WHERE folder_id = ?1
                     AND (rel_path = ?2 OR substr(rel_path, 1, length(?2) + 1) = ?2 || '/')",
@@ -321,6 +354,7 @@ impl Db {
                         remote_rev: r.get(4)?,
                         remote_hash: r.get(5)?,
                         local_mtime_ns: r.get(6)?,
+                        remote_revision_id: r.get(7)?,
                     })
                 })?
                 .collect::<rusqlite::Result<Vec<_>>>()?;
@@ -332,8 +366,8 @@ impl Db {
             let mut insert = tx.prepare(
                 "INSERT OR REPLACE INTO sync_entry
                    (folder_id, rel_path, remote_uid, local_mtime, local_size, remote_rev,
-                    remote_hash, local_mtime_ns)
-                 VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
+                    remote_hash, local_mtime_ns, remote_revision_id)
+                 VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9)",
             )?;
             for row in rows {
                 let rel = format!("{to_rel}{}", &row.rel_path[from_rel.len()..]);
@@ -346,6 +380,7 @@ impl Db {
                     row.remote_rev,
                     row.remote_hash,
                     row.local_mtime_ns,
+                    row.remote_revision_id,
                 ])?;
             }
         }

crates/pdfs-core/src/db/tests.rs

@@ -363,6 +363,23 @@ fn place_photos_carry_their_own_location() {
     );
 }
 
+/// A timeline photo names the town it was taken in, so the viewer can show it;
+/// one without a location names none.
+#[test]
+fn timeline_photos_name_their_town() {
+    let db = Db::open_in_memory().unwrap();
+    db.photos_replace(&[
+        located("b", 500, "IMG_5.JPG", BERLIN),
+        TimelineRow::new("n", 400),
+    ])
+    .unwrap();
+    let berlin = db.photo_places().unwrap()[0].id;
+    let mut photos = db.photos_by_uid(&["b".into(), "n".into()]).unwrap();
+    photos.sort_by(|a, b| a.uid.cmp(&b.uid));
+    let towns: Vec<Option<u32>> = photos.iter().map(|photo| photo.place_id).collect();
+    assert_eq!(towns, [Some(berlin), None]);
+}
+
 /// A refresh that skips an already-resolved photo keeps where it was taken; one
 /// that reads the node again takes what the node now says.
 #[test]
@@ -1283,6 +1300,90 @@ fn a_corrupt_database_is_moved_aside_and_rebuilt() {
     let _ = std::fs::remove_file(path.with_extension("db.lock"));
 }
 
+/// A rebuilt database must not lose what only this machine has: writes Drive
+/// has not received, the mirror baselines and the pins (`docs/BUGS.md` B216).
+#[test]
+fn a_rebuild_keeps_the_queue_baselines_and_pins_of_the_damaged_file() {
+    let id = now_test_id();
+    let damaged =
+        std::env::temp_dir().join(format!("pdfs-salvage-old-{}-{id}.db", std::process::id()));
+    let fresh =
+        std::env::temp_dir().join(format!("pdfs-salvage-new-{}-{id}.db", std::process::id()));
+
+    let db = Db::open(&damaged).unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&file("listed", "root", "listed.txt", 1))
+        .unwrap();
+    db.upsert_node(&file("queued", "root", "queued.txt", 2))
+        .unwrap();
+    db.set_listed(&uid("root"), true).unwrap();
+    db.enqueue_op(&PendingOp {
+        id: 0,
+        kind: OP_REVISION.to_string(),
+        uid: uid("queued").to_string(),
+        parent_uid: None,
+        name: None,
+        blob_path: Some("/staging/queued".into()),
+        meta_json: None,
+        created_at: 1,
+        attempts: 3,
+        last_error: None,
+        next_attempt_at: 0,
+    })
+    .unwrap();
+    let folder_id = db
+        .sync_folder_add("/home/me/Docs", "vol~docs", "share")
+        .unwrap();
+    db.sync_entry_upsert(
+        folder_id,
+        &StoredSyncEntry {
+            rel_path: "a.txt".into(),
+            remote_uid: Some("vol~a".into()),
+            local_mtime: 5,
+            local_mtime_ns: None,
+            local_size: 6,
+            remote_rev: Some("7".into()),
+            remote_hash: Some("8".into()),
+            remote_revision_id: None,
+        },
+    )
+    .unwrap();
+    db.pin_add("vol~pinned", "/pinned", true).unwrap();
+    drop(db);
+
+    let db = Db::open(&fresh).unwrap();
+    let results = salvage(&db.conn.lock(), &damaged);
+    assert!(results.iter().all(|(_, r)| r.is_ok()), "{results:?}");
+
+    let ops = db.pending_ops().unwrap();
+    assert_eq!(ops.len(), 1);
+    assert_eq!(ops[0].uid, uid("queued").to_string());
+    assert_eq!(ops[0].blob_path.as_deref(), Some("/staging/queued"));
+    // The op's node came with it; the rest of the tree is fetched again.
+    assert!(
+        db.node_by_uid(&uid("queued").to_string())
+            .unwrap()
+            .is_some()
+    );
+    assert!(
+        db.node_by_uid(&uid("listed").to_string())
+            .unwrap()
+            .is_none()
+    );
+    assert_eq!(db.sync_entries(folder_id).unwrap().len(), 1);
+    assert!(db.is_pinned("vol~pinned").unwrap());
+    drop(db);
+
+    for path in [&damaged, &fresh] {
+        for suffix in ["", "-wal", "-shm"] {
+            let mut file = path.as_os_str().to_owned();
+            file.push(suffix);
+            let _ = std::fs::remove_file(std::path::PathBuf::from(file));
+        }
+        let _ = std::fs::remove_file(path.with_extension("db.lock"));
+    }
+}
+
 fn local(path: &str, name: &str, is_dir: bool) -> LocalEntry {
     LocalEntry {
         path: path.into(),
@@ -1346,6 +1447,77 @@ fn rescanning_an_unchanged_file_keeps_exactly_one_index_entry() {
     }
 }
 
+/// A scan that stopped early or lost a batch did not see every file, so it
+/// must not prune the ones it missed (`docs/BUGS.md` B217).
+#[test]
+fn a_partial_local_scan_prunes_nothing() {
+    let db = Db::open_in_memory().unwrap();
+    let g = db.local_begin_scan().unwrap();
+    db.local_upsert_batch(
+        g,
+        &[
+            local("/home/u/a.txt", "a.txt", false),
+            local("/home/u/b.txt", "b.txt", false),
+        ],
+    )
+    .unwrap();
+    assert_eq!(db.local_finish_scan(g, 1).unwrap(), 2);
+
+    let g = db.local_begin_scan().unwrap();
+    db.local_upsert_batch(g, &[local("/home/u/a.txt", "a.txt", false)])
+        .unwrap();
+    assert_eq!(db.local_finish_partial_scan(2).unwrap(), 2);
+    assert_eq!(db.search_local("b.txt", 10).unwrap().len(), 1);
+    assert_eq!(db.local_indexed_at().unwrap(), Some(2));
+}
+
+/// Deleted entries pile up in an FTS5 index until it is compacted. The daily
+/// compaction must leave both indexes whole and searchable, and must not run
+/// again the same day (`docs/BUGS.md` B217).
+#[test]
+fn compacting_the_search_indexes_keeps_them_whole_and_runs_once_a_day() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&file("f1", "root", "quarterly-report.pdf", 1))
+        .unwrap();
+    for round in 0..20 {
+        let g = db.local_begin_scan().unwrap();
+        let name = format!("churn-{round}.txt");
+        db.local_upsert_batch(
+            g,
+            &[
+                local("/home/u/keep.txt", "keep.txt", false),
+                local(&format!("/home/u/{name}"), &name, false),
+            ],
+        )
+        .unwrap();
+        // Far in the past, so no scan compacts on its own.
+        db.local_finish_scan(g, 0).unwrap();
+    }
+
+    let day = 24 * 60 * 60;
+    db.compact_search_indexes_if_due(day).unwrap();
+    {
+        let conn = db.conn.lock();
+        for table in ["local_fts", "nodes_fts"] {
+            conn.execute(
+                &format!("INSERT INTO {table}({table}) VALUES('integrity-check')"),
+                [],
+            )
+            .unwrap();
+        }
+    }
+    assert_eq!(db.search_local("keep", 10).unwrap().len(), 1);
+    assert_eq!(db.search_local("churn-19", 10).unwrap().len(), 1);
+    assert!(db.search_local("churn-3.txt", 10).unwrap().is_empty());
+    assert_eq!(db.search("quarterly", 10).unwrap().len(), 1);
+    let stamp = |db: &Db| db.state_str("fts_compacted_at").unwrap();
+    assert_eq!(stamp(&db).as_deref(), Some(day.to_string().as_str()));
+
+    db.compact_search_indexes_if_due(day + 60).unwrap();
+    assert_eq!(stamp(&db).as_deref(), Some(day.to_string().as_str()));
+}
+
 /// Queries below the trigram minimum still match, via the `LIKE` fallback.
 #[test]
 fn local_search_short_query_like_fallback() {
@@ -1689,9 +1861,16 @@ fn writing_nodes_does_not_scale_with_the_size_of_the_index() {
             .collect();
         db.upsert_nodes(&batch).unwrap();
 
-        let t = Instant::now();
-        db.upsert_nodes(&batch).unwrap();
-        t.elapsed()
+        // The fastest of a few runs: the rest of the suite runs alongside, and
+        // one run that lost the CPU to it read as the regression.
+        (0..5)
+            .map(|_| {
+                let t = Instant::now();
+                db.upsert_nodes(&batch).unwrap();
+                t.elapsed()
+            })
+            .min()
+            .unwrap()
     }
 
     let small = cost_against_index_of(200);
@@ -1914,7 +2093,11 @@ fn migration_v17_adds_share_access_to_a_v16_fixture() {
     {
         let conn = rusqlite::Connection::open(&path).unwrap();
         conn.execute_batch(
-            "DROP TRIGGER mount_sync_folder_insert;
+            "DROP TRIGGER IF EXISTS mount_sync_folder_kind_update;
+             DROP TRIGGER mount_sync_folder_insert;
+             DROP TRIGGER sync_folder_attached_insert;
+             DROP TRIGGER sync_folder_attached_update;
+             ALTER TABLE sync_folder DROP COLUMN kind;
              DROP TABLE mount;
              DROP TABLE share_access;
              DROP TABLE album_photos;
@@ -2191,6 +2374,100 @@ fn refuses_a_schema_newer_than_the_running_build() {
     let _ = std::fs::remove_file(path);
 }
 
+/// Queueing a write syncs it to disk, and leaves the writer at NORMAL after.
+///
+/// The op row is what makes a staged blob reachable once `close()` has
+/// reported success, so its commit must survive a power loss. Everything else
+/// the writer commits is metadata the next listing re-fetches, and pays only
+/// NORMAL's cost.
+#[test]
+fn queueing_a_write_commits_at_full_sync_and_restores_normal() {
+    let path = std::env::temp_dir().join(format!("pdfs-db-sync-{}.db", std::process::id()));
+    let _ = std::fs::remove_file(&path);
+    let db = Db::open(&path).unwrap();
+    let level = |db: &Db| -> i64 {
+        db.conn
+            .lock()
+            .query_row("PRAGMA synchronous", [], |r| r.get(0))
+            .unwrap()
+    };
+    // 1 = NORMAL, 2 = FULL.
+    assert_eq!(level(&db), 1);
+    {
+        let durable = db.durable().unwrap();
+        let during: i64 = durable
+            .query_row("PRAGMA synchronous", [], |r| r.get(0))
+            .unwrap();
+        assert_eq!(during, 2);
+    }
+    assert_eq!(level(&db), 1);
+
+    db.enqueue_op(&PendingOp {
+        id: 0,
+        kind: OP_TRASH.to_string(),
+        uid: uid("a").to_string(),
+        parent_uid: None,
+        name: Some("a".to_string()),
+        blob_path: None,
+        meta_json: None,
+        created_at: 1,
+        attempts: 0,
+        last_error: None,
+        next_attempt_at: 0,
+    })
+    .unwrap();
+    assert_eq!(level(&db), 1);
+    assert_eq!(db.pending_ops().unwrap().len(), 1);
+    drop(db);
+    for suffix in ["", "-wal", "-shm"] {
+        let _ = std::fs::remove_file(format!("{}{suffix}", path.display()));
+    }
+}
+
+/// A gap-filled blob is recorded as whole only while the op still holds it.
+///
+/// A write that closes during the drain points the row at a newer blob with
+/// its own sidecar. Overwriting that sidecar with the older blob's would
+/// describe bytes the row no longer holds.
+#[test]
+fn marking_a_blob_whole_leaves_a_newer_blob_alone() {
+    let db = Db::open_in_memory().unwrap();
+    let op = PendingOp {
+        id: 0,
+        kind: OP_REVISION.to_string(),
+        uid: uid("a").to_string(),
+        parent_uid: None,
+        name: None,
+        blob_path: Some("/staging/first".to_string()),
+        meta_json: Some(r#"{"complete":false}"#.to_string()),
+        created_at: 1,
+        attempts: 0,
+        last_error: None,
+        next_attempt_at: 0,
+    };
+    db.enqueue_op(&op).unwrap();
+    let id = db.pending_ops().unwrap()[0].id;
+
+    assert!(
+        db.update_op_meta_for_blob(id, "/staging/first", r#"{"complete":true}"#)
+            .unwrap()
+    );
+    assert_eq!(
+        db.pending_ops().unwrap()[0].meta_json.as_deref(),
+        Some(r#"{"complete":true}"#)
+    );
+
+    assert!(
+        !db.update_op_meta_for_blob(id, "/staging/older", r#"{"stale":true}"#)
+            .unwrap(),
+        "the row holds another blob"
+    );
+    assert_eq!(
+        db.pending_ops().unwrap()[0].meta_json.as_deref(),
+        Some(r#"{"complete":true}"#)
+    );
+}
+
 /// A queued write whose baseline is restamped must keep everything else.
 ///
 /// The restamp happens after our *own* upload seals a new revision under a
@@ -3920,15 +4197,15 @@ fn what_a_create_sent_outlives_a_newer_blob_its_trash_and_a_restart() {
             .unwrap();
         assert!(db.create_sent(id).unwrap().is_empty());
         assert!(db.create_targets(id).unwrap().is_empty());
-        db.note_create_target(id, &parent, "c").unwrap();
-        db.note_create_target(id, &parent, "c").unwrap();
+        db.note_create_target(id, &parent, "c", 10).unwrap();
+        db.note_create_target(id, &parent, "c", 20).unwrap();
         db.note_create_sent(id, "aaaa").unwrap();
         db.note_create_sent(id, "aaaa").unwrap();
         db.record_op_failure(id, "no answer", 0).unwrap();
         db.attach_blob_to_create("local~sent", "/staging/second", "{}")
             .unwrap()
             .expect("the create is still queued");
-        db.note_create_target(id, &parent, "d").unwrap();
+        db.note_create_target(id, &parent, "d", 30).unwrap();
         db.note_create_sent(id, "bbbb").unwrap();
         db.record_op_failure(id, "no answer", 0).unwrap();
         db.delete_ops_for_uid("local~sent").unwrap();
@@ -3951,6 +4228,73 @@ fn what_a_create_sent_outlives_a_newer_blob_its_trash_and_a_restart() {
     let _ = std::fs::remove_file(path);
 }
 
+/// A queued create knows when it first went out, which is where the window
+/// for adopting a node its lost answer left starts. Records written before
+/// the time was kept still list their targets, and one that does not parse is
+/// not replaced by the next target.
+#[test]
+fn a_create_remembers_when_it_was_first_sent() {
+    let db = Db::open_in_memory().unwrap();
+    let parent = uid("parent").to_string();
+    let (id, _) = db
+        .enqueue_op(&PendingOp {
+            id: 0,
+            kind: OP_CREATE.to_string(),
+            uid: "local~first".to_string(),
+            parent_uid: Some(parent.clone()),
+            name: Some("a.txt".to_string()),
+            blob_path: None,
+            meta_json: None,
+            created_at: 1,
+            attempts: 0,
+            last_error: None,
+            next_attempt_at: 0,
+        })
+        .unwrap();
+    assert_eq!(db.create_first_sent(id).unwrap(), None, "never sent");
+    db.note_create_target(id, &parent, "a.txt", 500).unwrap();
+    db.note_create_target(id, &parent, "a.txt", 900).unwrap();
+    db.note_create_target(id, &parent, "b.txt", 700).unwrap();
+    assert_eq!(db.create_first_sent(id).unwrap(), Some(500));
+
+    let set = |json: &str| {
+        db.conn
+            .lock()
+            .execute(
+                "UPDATE pending_op SET sent_to = ?2 WHERE id = ?1",
+                rusqlite::params![id, json],
+            )
+            .unwrap();
+    };
+    set(&format!(r#"[["{parent}","old.txt"]]"#));
+    assert_eq!(
+        db.create_targets(id).unwrap(),
+        vec![(parent.clone(), "old.txt".to_string())]
+    );
+    assert_eq!(db.create_first_sent(id).unwrap(), None);
+    db.note_create_target(id, &parent, "a.txt", 900).unwrap();
+    assert_eq!(
+        db.create_targets(id).unwrap().len(),
+        2,
+        "the old target stays"
+    );
+    assert_eq!(db.create_first_sent(id).unwrap(), Some(900));
+
+    set("not json");
+    db.note_create_target(id, &parent, "c.txt", 1000).unwrap();
+    let raw: String = db
+        .conn
+        .lock()
+        .query_row("SELECT sent_to FROM pending_op WHERE id = ?1", [id], |r| {
+            r.get(0)
+        })
+        .unwrap();
+    assert_eq!(
+        raw, "not json",
+        "an unreadable record is kept, not replaced"
+    );
+}
+
 /// A write after a create failed clears its attempts, so the next try goes
 /// out at once. The create was still sent: deleting the file then left no
 /// trash, and the file a lost answer made stayed on Drive under the name it
@@ -3974,7 +4318,7 @@ fn a_create_rewritten_after_it_failed_still_leaves_a_trash_when_deleted() {
             next_attempt_at: 0,
         })
         .unwrap();
-    db.note_create_target(id, &parent, "a.txt").unwrap();
+    db.note_create_target(id, &parent, "a.txt", 10).unwrap();
     db.note_create_sent(id, "aaaa").unwrap();
     db.record_op_failure(id, "no answer", 0).unwrap();
     db.attach_blob_to_create("local~sent", "/staging/second", "{}")
@@ -5021,6 +5365,7 @@ fn baseline_row(rel: &str) -> StoredSyncEntry {
         local_size: 7,
         remote_rev: Some("1700000000".into()),
         remote_hash: Some("7".into()),
+        remote_revision_id: None,
     }
 }
 
@@ -5115,6 +5460,7 @@ fn mirror_uid_lookup_covers_the_root_and_synced_descendants_only() {
             local_size: 2,
             remote_rev: Some("3".into()),
             remote_hash: Some("2".into()),
+            remote_revision_id: None,
             local_mtime_ns: None,
         },
     )
@@ -5132,6 +5478,7 @@ fn mirror_uid_lookup_covers_the_root_and_synced_descendants_only() {
             local_size: 2,
             remote_rev: Some("3".into()),
             remote_hash: Some("2".into()),
+            remote_revision_id: None,
             local_mtime_ns: None,
         },
     )
@@ -6309,6 +6656,71 @@ fn migration_v27_adds_the_access_deferral_column_to_a_v26_queue() {
     let _ = std::fs::remove_file(format!("{}.lock", path.display()));
 }
 
+/// V44 adds the remote revision a baseline row was synced at. A row carried
+/// over from V43 has none, and the mirror then compares the modification time
+/// and size as before, so upgrading changes nothing about what is in step
+/// (`docs/BUGS.md` B249).
+#[test]
+fn migration_v44_adds_the_synced_revision_without_disturbing_a_v43_baseline() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-db-v43-fixture-{}-{}.db",
+        std::process::id(),
+        std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos()
+    ));
+    let row = StoredSyncEntry {
+        rel_path: "notes.txt".into(),
+        remote_uid: Some("vol~notes".into()),
+        local_mtime: 1_700_000_000,
+        local_mtime_ns: Some(1_700_000_000_123_456_789),
+        local_size: 42,
+        remote_rev: Some("1700000000".into()),
+        remote_hash: Some("42".into()),
+        remote_revision_id: Some("rev-1".into()),
+    };
+    {
+        let db = Db::open(&path).unwrap();
+        let folder = db
+            .sync_folder_add("/home/me/Mirror", "vol~root", "share")
+            .unwrap();
+        db.sync_entry_upsert(folder, &row).unwrap();
+    }
+    {
+        // Put the file back in the state a released V43 database was in.
+        let conn = rusqlite::Connection::open(&path).unwrap();
+        conn.execute_batch(
+            "ALTER TABLE sync_entry DROP COLUMN remote_revision_id;
+             UPDATE sync_state SET value = '43' WHERE key = 'schema_version';",
+        )
+        .unwrap();
+    }
+
+    let db = Db::open(&path).unwrap();
+    let entries = db.sync_entries(1).unwrap();
+    let entry = entries.get("notes.txt").expect("the baseline row survives");
+    assert_eq!(
+        entry,
+        &StoredSyncEntry {
+            remote_revision_id: None,
+            ..row.clone()
+        }
+    );
+
+    // And the column is live, including through a move of the row.
+    db.sync_entry_upsert(1, &row).unwrap();
+    db.sync_entries_move(1, "notes.txt", 1, "moved.txt")
+        .unwrap();
+    let entries = db.sync_entries(1).unwrap();
+    assert_eq!(
+        entries["moved.txt"].remote_revision_id.as_deref(),
+        Some("rev-1")
+    );
+    drop(db);
+    let _ = std::fs::remove_file(&path);
+}
+
 /// A mirror baseline carried over from V27 keeps its rows, and each one reads
 /// back with no nanosecond time. That `None` is the whole point: it makes the
 /// comparison fall back to whole seconds for rows written before the column
@@ -6339,6 +6751,7 @@ fn migration_v28_adds_sub_second_local_times_without_disturbing_a_v27_baseline()
                 local_size: 42,
                 remote_rev: Some("1700000000".into()),
                 remote_hash: Some("42".into()),
+                remote_revision_id: None,
             },
         )
         .unwrap();
@@ -7209,6 +7622,56 @@ fn a_refused_change_names_its_node_by_local_id() {
     );
 }
 
+/// The name checks the drain makes before each op look the name up in an
+/// index. Scanning the queue instead made a large offline batch quadratic.
+#[test]
+fn queue_name_checks_use_an_index() {
+    let db = Db::open_in_memory().unwrap();
+    let conn = db.conn.lock();
+    let plan = |sql: &str| -> String {
+        let mut stmt = conn.prepare(&format!("EXPLAIN QUERY PLAN {sql}")).unwrap();
+        stmt.query_map([], |r| r.get::<_, String>(3))
+            .unwrap()
+            .map(|row| row.unwrap())
+            .collect::<Vec<_>>()
+            .join("; ")
+    };
+    for sql in [
+        "SELECT 1 FROM pending_op WHERE kind = 'trash' AND name = 'a'",
+        "SELECT 1 FROM pending_op WHERE name = 'a' AND kind IN ('create', 'mkdir', 'rename')",
+        "SELECT 1 FROM pending_op WHERE kind = 'rename'",
+    ] {
+        let plan = plan(sql);
+        assert!(plan.contains("pending_op_kind_name"), "{sql}: {plan}");
+    }
+}
+
+/// A reconnect moves up the ops that failed for want of a link. One Drive
+/// refused, for quota or access, keeps its backoff: the link coming back
+/// changes nothing about it. "Retry all" still moves both.
+#[test]
+fn a_reconnect_leaves_refused_ops_to_their_backoff() {
+    let db = Db::open_in_memory().unwrap();
+    let offline = queued_op(&db, "vol~a", 2, 90_000);
+    let refused = queued_op(&db, "vol~b", 2, 90_000);
+    db.set_op_issue(refused, Some("quota")).unwrap();
+
+    assert_eq!(db.retry_unrefused_ops_now(5_000).unwrap(), 1);
+    let due = |id: i64| {
+        db.pending_ops()
+            .unwrap()
+            .into_iter()
+            .find(|op| op.id == id)
+            .unwrap()
+            .next_attempt_at
+    };
+    assert_eq!(due(offline), 5_000);
+    assert_eq!(due(refused), 90_000);
+
+    assert_eq!(db.retry_failed_ops_now(5_000).unwrap(), 1);
+    assert_eq!(due(refused), 5_000);
+}
+
 #[test]
 fn retry_all_touches_only_ops_that_have_failed() {
     let db = Db::open_in_memory().unwrap();
@@ -7249,3 +7712,69 @@ fn a_queued_op_stops_existing_once_the_node_is_deleted() {
     assert_eq!(blobs, vec!["/staging/journal"]);
     assert!(!db.op_exists(id).unwrap());
 }
+
+#[test]
+fn attachments_have_their_own_location_and_cannot_evict_local_files() {
+    use crate::mounts::MountKind;
+    let db = Db::open_in_memory().unwrap();
+    let id = db
+        .sync_folder_attach("/work", "vol~work", "myfiles-share")
+        .unwrap();
+    let folder = db.sync_folder_get(id).unwrap().unwrap();
+    assert_eq!(folder.kind, "attached");
+    assert_eq!(folder.mode, "mirror");
+    assert_eq!(db.sync_folder_list().unwrap()[0].kind, "attached");
+    let locations = db.mount_list().unwrap();
+    assert!(
+        matches!(locations[0].kind, MountKind::Attached { sync_folder_id } if sync_folder_id == id)
+    );
+    assert_eq!(locations[0].local_path, "/work");
+    assert_eq!(locations[0].root_share_id, "myfiles-share");
+    assert!(db.sync_folder_set_mode(id, "ondemand").is_err());
+    assert!(
+        db.sync_folder_set_pending_mode(id, Some("ondemand"))
+            .is_err()
+    );
+    assert_eq!(db.sync_folder_get(id).unwrap().unwrap().mode, "mirror");
+    db.sync_folder_remove(id).unwrap();
+    assert!(db.mount_list().unwrap().is_empty());
+}
+
+#[test]
+fn migration_v45_keeps_existing_device_folders_and_location_ids() {
+    let db = Db::open_in_memory().unwrap();
+    let id = db
+        .sync_folder_add("/backup", "vol~backup", "share")
+        .unwrap();
+    db.sync_folder_set_mode(id, "ondemand").unwrap();
+    db.sync_folder_set_pending_mode(id, Some("mirror")).unwrap();
+    let location_id = db.mount_list().unwrap()[0].id;
+    db.conn
+        .lock()
+        .execute_batch(
+            "DROP TRIGGER sync_folder_attached_insert;
+         DROP TRIGGER sync_folder_attached_update;
+         DROP TRIGGER IF EXISTS mount_sync_folder_kind_update;
+         DROP TRIGGER mount_sync_folder_insert;
+         ALTER TABLE sync_folder DROP COLUMN kind;
+         CREATE TRIGGER mount_sync_folder_insert AFTER INSERT ON sync_folder BEGIN
+           INSERT INTO mount (kind, sync_folder_id) VALUES ('device', NEW.id); END;
+         UPDATE sync_state SET value = '44' WHERE key = 'schema_version';",
+        )
+        .unwrap();
+    db.migrate().unwrap();
+    let folder = db.sync_folder_get(id).unwrap().unwrap();
+    assert_eq!(folder.kind, "device");
+    assert_eq!(folder.mode, "ondemand");
+    assert_eq!(folder.pending_mode.as_deref(), Some("mirror"));
+    assert_eq!(db.mount_list().unwrap()[0].id, location_id);
+    let attached = db
+        .sync_folder_attach("/work", "vol~work", "myfiles")
+        .unwrap();
+    assert_eq!(
+        db.sync_folder_get(attached).unwrap().unwrap().kind,
+        "attached"
+    );
+    db.migrate().unwrap();
+    assert_eq!(db.mount_list().unwrap().len(), 2);
+}

crates/pdfs-core/src/error.rs

@@ -154,19 +154,20 @@ impl CoreError {
     /// through the boxes the drain deals in, where the concrete type survives
     /// but the static one does not.
     ///
-    /// A failure that is not an API response at all — a transport error, a
-    /// timeout, a TLS failure — is what being offline looks like from here, so
-    /// it classifies as [`ErrorKind::Offline`] rather than
-    /// [`ErrorKind::Remote`]: the request never reached Proton, and telling the
-    /// user their connection is down beats telling them the server refused.
+    /// A transport error, a timeout or a TLS failure is what being offline
+    /// looks like from here, so it classifies as [`ErrorKind::Offline`] rather
+    /// than [`ErrorKind::Remote`]: the request never reached Proton, and
+    /// telling the user their connection is down beats telling them the
+    /// server refused. The SDK's other failures say what went wrong instead
+    /// (see [`proton_kind`]).
+    ///
+    /// Callers also hand it this crate's [`Error`] from the cache and the
+    /// database, which is not a transport error at all. Taking those for
+    /// "offline" told the user their connection was down when a pin failed on
+    /// the database (`docs/BUGS.md` B266), so the source chain is searched for
+    /// either type before falling back.
     pub fn from_api(e: &(dyn std::error::Error + 'static), what: &str) -> Self {
-        let kind = match e.downcast_ref::<proton_sdk::ProtonError>() {
-            Some(proton_sdk::ProtonError::Api(api)) => api_kind(api.code),
-            // A `ProtonError` that is not an `Api` variant never reached the
-            // API; so does anything that is not a `ProtonError` at all.
-            _ => ErrorKind::Offline,
-        };
-        Self::new(kind, format!("{what}: {e}"))
+        Self::new(api_kind_of(e), format!("{what}: {e}"))
     }
 
     /// Prefix the message while keeping the classification.
@@ -208,18 +209,57 @@ impl From<serde_json::Error> for CoreError {
 
 impl From<Error> for CoreError {
     fn from(e: Error) -> Self {
-        let kind = match &e {
-            Error::NotLoggedIn
-            | Error::ReloginRequired
-            | Error::Locked
-            | Error::WrongMailboxPassword
-            | Error::HumanVerificationRequired(_) => ErrorKind::Denied,
-            Error::Proton(proton_sdk::ProtonError::Api(api)) => api_kind(api.code),
-            // A `ProtonError` that never reached the API is a transport failure.
-            Error::Proton(_) => ErrorKind::Offline,
-            _ => ErrorKind::Internal,
-        };
-        Self::new(kind, e.to_string())
+        Self::new(core_kind(&e), e.to_string())
+    }
+}
+
+/// What this crate's [`Error`] means to a front-end.
+fn core_kind(e: &Error) -> ErrorKind {
+    match e {
+        Error::NotLoggedIn
+        | Error::ReloginRequired
+        | Error::Locked
+        | Error::WrongMailboxPassword
+        | Error::HumanVerificationRequired(_) => ErrorKind::Denied,
+        Error::Proton(proton) => proton_kind(proton),
+        _ => ErrorKind::Internal,
+    }
+}
+
+/// The kind for [`CoreError::from_api`]: the first SDK or crate error in `e`'s
+/// source chain decides it.
+fn api_kind_of(e: &(dyn std::error::Error + 'static)) -> ErrorKind {
+    let mut cause = Some(e);
+    while let Some(err) = cause {
+        if let Some(proton) = err.downcast_ref::<proton_sdk::ProtonError>() {
+            return proton_kind(proton);
+        }
+        if let Some(core) = err.downcast_ref::<Error>() {
+            return core_kind(core);
+        }
+        cause = err.source();
+    }
+    // Not the SDK's at all: a timeout around the call, or the socket.
+    ErrorKind::Offline
+}
+
+/// What a failed SDK call means to a front-end.
+///
+/// Only a transport failure is the connection. The rest happened on this
+/// machine, and calling them "offline" sent the user to check a network that
+/// worked (issue #38: a photo upload on an account without a photo library
+/// read "You're offline").
+fn proton_kind(e: &proton_sdk::ProtonError) -> ErrorKind {
+    use proton_sdk::ProtonError as P;
+    match e {
+        P::Api(api) => api_kind(api.code),
+        P::Transport(_) => ErrorKind::Offline,
+        // Proton answered, but not with anything this client can read.
+        P::Serialization(_) => ErrorKind::Remote,
+        // The SDK refused the call before sending it, such as an upload to a
+        // photo library the account does not have.
+        P::InvalidOperation(_) => ErrorKind::Invalid,
+        P::Crypto(_) | P::KeysLocked => ErrorKind::Internal,
     }
 }
 
@@ -295,6 +335,15 @@ pub fn session_revoked(e: &proton_sdk::ProtonError) -> bool {
     }
 }
 
+/// Whether `e` is Proton's temporary block on a sign-in (code 2028).
+///
+/// Its message says the app version is no longer supported, which is not what
+/// happened: the release is current and only waiting helps (issues #28, #39).
+/// A front-end must say that instead of passing the message through.
+pub fn sign_in_blocked(e: &proton_sdk::ProtonError) -> bool {
+    matches!(e, proton_sdk::ProtonError::Api(api) if api.code == proton_sdk::api::ResponseCode::Blocked)
+}
+
 /// The result every request-serving method in the daemon returns.
 pub type CoreResult<T> = std::result::Result<T, CoreError>;
 
@@ -337,6 +386,14 @@ mod tests {
         assert!(!session_revoked(&ProtonError::KeysLocked));
     }
 
+    #[test]
+    fn only_code_2028_is_a_blocked_sign_in() {
+        assert!(sign_in_blocked(&api(C::Blocked)));
+        assert!(!sign_in_blocked(&api(C::OutdatedApp)));
+        assert!(!sign_in_blocked(&api(C::TooManyRequests)));
+        assert!(!sign_in_blocked(&ProtonError::KeysLocked));
+    }
+
     /// The regression this whole pass exists to prevent: before it, every SDK
     /// failure was hardcoded to `Remote`, so a 403 asked the user to retry a
     /// request that could never succeed.
@@ -367,6 +424,32 @@ mod tests {
         assert_eq!(CoreError::from_api(&io, "list").kind, ErrorKind::Offline);
     }
 
+    /// Issue #38: the SDK refused a photo upload before sending it, and the
+    /// app said "You're offline" while every other call went through.
+    #[test]
+    fn a_call_the_sdk_refuses_to_send_is_not_offline() {
+        let refused = ProtonError::invalid_operation("account has no photos volume");
+        let e = CoreError::from_api(&refused, "upload photo failed");
+        assert_eq!(e.kind, ErrorKind::Invalid);
+        assert!(e.message.ends_with("account has no photos volume"));
+        let e: CoreError = Error::Proton(ProtonError::KeysLocked).into();
+        assert_ne!(e.kind, ErrorKind::Offline);
+    }
+
+    /// A pin or a search that fails on the database is not the connection, so
+    /// it must not say "You're offline" (`docs/BUGS.md` B266). An SDK error
+    /// wrapped in this crate's type classifies as the SDK error does.
+    #[test]
+    fn a_database_error_handed_to_from_api_is_not_offline() {
+        let db = Error::Other("database is locked".into());
+        assert_eq!(CoreError::from_api(&db, "pin").kind, ErrorKind::Internal);
+        let wrapped = Error::Proton(api(C::DoesNotExist));
+        assert_eq!(
+            CoreError::from_api(&wrapped, "load node").kind,
+            ErrorKind::NotFound
+        );
+    }
+
     /// `Error` is the plumbing type; converting it must classify as sharply as
     /// the direct path, or the two disagree about the same failure.
     #[test]

crates/pdfs-core/src/exiftime.rs

@@ -0,0 +1,133 @@
+//! When a photo was taken, as its own EXIF tags say.
+//!
+//! The fallback for a photo nothing else dates: a Takeout photo without a
+//! sidecar or a date in its name, and a photo uploaded from the app. Without
+//! it the first was filed under the moment of the import and the second under
+//! the file's modification time, which a copy resets.
+
+use std::io::{BufRead, Seek};
+use std::path::Path;
+
+use crate::takeout::days_from_civil;
+
+/// The capture time in the EXIF of the file at `path`, in epoch seconds.
+pub fn capture_time_of(path: &Path) -> Option<i64> {
+    let file = std::fs::File::open(path).ok()?;
+    capture_time(&mut std::io::BufReader::new(file))
+}
+
+/// The capture time in the EXIF `reader` holds: `DateTimeOriginal`, then
+/// `DateTimeDigitized`, each adjusted by its `OffsetTime…` tag when the camera
+/// wrote one. Without an offset the time is read as UTC, as a date in a file
+/// name is (`takeout::capture_time_from_name`).
+pub fn capture_time(reader: &mut (impl BufRead + Seek)) -> Option<i64> {
+    let exif = exif::Reader::new().read_from_container(reader).ok()?;
+    let ascii = |tag: exif::Tag| -> Option<String> {
+        let field = exif.get_field(tag, exif::In::PRIMARY)?;
+        match &field.value {
+            exif::Value::Ascii(parts) => parts.first().map(|part| {
+                String::from_utf8_lossy(part)
+                    .trim_matches('\0')
+                    .trim()
+                    .to_string()
+            }),
+            _ => None,
+        }
+    };
+    [
+        (exif::Tag::DateTimeOriginal, exif::Tag::OffsetTimeOriginal),
+        (exif::Tag::DateTimeDigitized, exif::Tag::OffsetTimeDigitized),
+    ]
+    .into_iter()
+    .find_map(|(time, offset)| {
+        let local = parse_exif_time(&ascii(time)?)?;
+        let offset = ascii(offset).and_then(|o| parse_offset(&o)).unwrap_or(0);
+        Some(local - offset)
+    })
+}
+
+/// `YYYY:MM:DD HH:MM:SS` as epoch seconds, read as UTC. `None` for the
+/// all-zero or blank value cameras write when they do not know.
+fn parse_exif_time(text: &str) -> Option<i64> {
+    let bytes = text.as_bytes();
+    if bytes.len() < 19 || bytes[4] != b':' || bytes[7] != b':' || bytes[13] != b':' {
+        return None;
+    }
+    let number = |range: std::ops::Range<usize>| text.get(range)?.parse::<i64>().ok();
+    let (year, month, day) = (number(0..4)?, number(5..7)?, number(8..10)?);
+    let (hour, minute, second) = (number(11..13)?, number(14..16)?, number(17..19)?);
+    if !(1800..=9999).contains(&year)
+        || !(1..=12).contains(&month)
+        || !(1..=31).contains(&day)
+        || hour > 23
+        || minute > 59
+        || second > 60
+    {
+        return None;
+    }
+    Some(days_from_civil(year, month, day) * 86_400 + hour * 3600 + minute * 60 + second)
+}
+
+/// `+HH:MM` or `-HH:MM` as seconds east of UTC.
+fn parse_offset(text: &str) -> Option<i64> {
+    let sign = match text.as_bytes().first()? {
+        b'+' => 1,
+        b'-' => -1,
+        _ => return None,
+    };
+    let (hours, minutes) = text.get(1..)?.split_once(':')?;
+    let (hours, minutes) = (hours.parse::<i64>().ok()?, minutes.parse::<i64>().ok()?);
+    (hours <= 14 && minutes < 60).then_some(sign * (hours * 3600 + minutes * 60))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn an_exif_time_reads_as_utc_and_its_offset_moves_it() {
+        // 2023-06-01 12:00:00 UTC.
+        let noon = 1_685_620_800;
+        assert_eq!(parse_exif_time("2023:06:01 12:00:00"), Some(noon));
+        assert_eq!(parse_offset("+02:00"), Some(7200));
+        assert_eq!(parse_offset("-05:30"), Some(-19_800));
+        assert_eq!(
+            parse_exif_time("2023:06:01 14:00:00").map(|t| t - parse_offset("+02:00").unwrap()),
+            Some(noon)
+        );
+    }
+
+    #[test]
+    fn an_unknown_exif_time_is_no_time() {
+        assert_eq!(parse_exif_time("0000:00:00 00:00:00"), None);
+        assert_eq!(parse_exif_time("    :  :     :  :  "), None);
+        assert_eq!(parse_exif_time(""), None);
+        assert_eq!(parse_offset("02:00"), None);
+    }
+
+    #[test]
+    fn a_photo_is_dated_by_its_original_time_and_offset() {
+        let ascii = |tag, text: &str| exif::Field {
+            tag,
+            ifd_num: exif::In::PRIMARY,
+            value: exif::Value::Ascii(vec![text.as_bytes().to_vec()]),
+        };
+        let taken = ascii(exif::Tag::DateTimeOriginal, "2023:06:01 14:00:00");
+        let offset = ascii(exif::Tag::OffsetTimeOriginal, "+02:00");
+        let digitized = ascii(exif::Tag::DateTimeDigitized, "2024:01:01 00:00:00");
+        let mut writer = exif::experimental::Writer::new();
+        writer.push_field(&taken);
+        writer.push_field(&offset);
+        writer.push_field(&digitized);
+        let mut tiff = std::io::Cursor::new(Vec::new());
+        writer.write(&mut tiff, false).unwrap();
+        tiff.set_position(0);
+        assert_eq!(capture_time(&mut tiff), Some(1_685_620_800));
+    }
+
+    #[test]
+    fn a_file_without_exif_has_no_capture_time() {
+        let mut png = std::io::Cursor::new(b"\x89PNG\r\n\x1a\n".to_vec());
+        assert_eq!(capture_time(&mut png), None);
+    }
+}

crates/pdfs-core/src/keycheck.rs

@@ -0,0 +1,294 @@
+//! Trace the key chain that opens My Files, for `pdfs diagnose`.
+//!
+//! The daemon only says "missing key" when the My Files share does not open
+//! (#40). This walks the chain the other way and names the link that breaks:
+//! the share's passphrase is encrypted to an address key, whose token is
+//! encrypted to an account key, which opens with the stored passphrase. Every
+//! finding holds key IDs and flags only, never key material, so the output is
+//! safe to post in an issue.
+
+use proton_sdk::account::{AddressKeyReport, KeyReport, UserKeyReport};
+use proton_sdk::ids::AddressId;
+
+use crate::auth;
+use crate::error::Result;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Level {
+    Ok,
+    Warn,
+    Fail,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Finding {
+    pub level: Level,
+    pub label: String,
+    pub detail: String,
+}
+
+/// The address and recipients of the My Files share passphrase, or why they
+/// could not be read.
+pub type ShareRecipients = std::result::Result<(AddressId, Vec<Option<String>>), String>;
+
+/// Resume the stored session and ask Proton for the account's keys and the
+/// My Files share. Fails when there is no session, the keys are locked, or
+/// Proton cannot be reached; reading the share is allowed to fail on its own.
+///
+/// The session's tokens are the daemon's too. A refresh here spends the
+/// refresh token the daemon holds, which it recovers from by resuming the
+/// stored session (see [`auth::stored_session_is_newer`]).
+pub async fn run() -> Result<(KeyReport, ShareRecipients)> {
+    let (client, _session) = auth::resume_client().await?;
+    let report = client.account().key_report().await?;
+    let share = client
+        .my_files_share_recipients()
+        .await
+        .map_err(|e| e.to_string());
+    Ok((report, share))
+}
+
+/// One finding per key, then one for the My Files share.
+pub fn findings(report: &KeyReport, share: &ShareRecipients) -> Vec<Finding> {
+    let mut findings = Vec::new();
+    for key in &report.user_keys {
+        findings.push(user_key_finding(key));
+    }
+    for address in &report.addresses {
+        for key in &address.keys {
+            findings.push(address_key_finding(report, &address.email, key));
+        }
+    }
+    findings.push(share_finding(report, share));
+    findings
+}
+
+fn user_key_finding(key: &UserKeyReport) -> Finding {
+    let label = format!("account key {}", short(key.id.as_str()));
+    let (level, detail) = match (key.active, key.unlocks) {
+        (true, true) => (Level::Ok, "opens".to_string()),
+        (true, false) => (
+            Level::Fail,
+            format!(
+                "does not open: {}",
+                key.error.as_deref().unwrap_or("unknown")
+            ),
+        ),
+        (false, true) => (Level::Ok, "inactive, opens with your password".to_string()),
+        (false, false) => (Level::Ok, "inactive, does not open".to_string()),
+    };
+    Finding {
+        level,
+        label,
+        detail: with_primary(key.primary, detail),
+    }
+}
+
+fn address_key_finding(report: &KeyReport, email: &str, key: &AddressKeyReport) -> Finding {
+    let label = format!("{email} key {}", short(key.id.as_str()));
+    let (level, detail) = if !key.active {
+        (Level::Ok, "inactive, not used".to_string())
+    } else if key.unlocks {
+        (Level::Ok, "opens".to_string())
+    } else {
+        // A non-primary key matters only for what was encrypted to it; the
+        // share finding says whether My Files is.
+        let level = if key.primary {
+            Level::Fail
+        } else {
+            Level::Warn
+        };
+        (level, format!("does not open: {}", why_closed(report, key)))
+    };
+    Finding {
+        level,
+        label,
+        detail: with_primary(key.primary, detail),
+    }
+}
+
+/// Why an active address key does not open, named by the account key its
+/// token was meant for when the token has one.
+fn why_closed(report: &KeyReport, key: &AddressKeyReport) -> String {
+    let error = key.error.as_deref().unwrap_or("unknown");
+    let Some(recipients) = &key.token_recipients else {
+        return error.to_string();
+    };
+    let named: Vec<&str> = recipients.iter().flatten().map(String::as_str).collect();
+    if let Some(user_key) = named.iter().find_map(|r| report.user_key_named(r)) {
+        let id = short(user_key.id.as_str());
+        return match (user_key.active, user_key.unlocks) {
+            (false, true) => {
+                format!(
+                    "its token is for inactive account key {id}, which opens with your password"
+                )
+            }
+            (false, false) => {
+                format!("its token is for inactive account key {id}, which does not open either")
+            }
+            (true, false) => format!("its token is for account key {id}, which does not open"),
+            // The token opened; the key itself refused its passphrase.
+            (true, true) => error.to_string(),
+        };
+    }
+    match named.first() {
+        Some(recipient) => {
+            format!("its token is for key {recipient}, which is none of your account keys")
+        }
+        None if recipients.is_empty() => error.to_string(),
+        None => "its token does not name the key it is for".to_string(),
+    }
+}
+
+fn share_finding(report: &KeyReport, share: &ShareRecipients) -> Finding {
+    let label = "My Files share".to_string();
+    let (level, detail) = match share {
+        Err(e) => (Level::Warn, format!("could not be read: {e}")),
+        Ok((address_id, recipients)) => {
+            let named: Vec<&str> = recipients.iter().flatten().map(String::as_str).collect();
+            match named.iter().find_map(|r| report.address_key_named(r)) {
+                Some((address, key)) => {
+                    let name = format!("{} key {}", address.email, short(key.id.as_str()));
+                    if key.unlocks {
+                        (Level::Ok, format!("encrypted to {name}, which opens"))
+                    } else {
+                        (
+                            Level::Fail,
+                            format!("encrypted to {name}, which does not open"),
+                        )
+                    }
+                }
+                None => (
+                    Level::Fail,
+                    match named.first() {
+                        Some(recipient) => format!(
+                            "encrypted to key {recipient}, which is none of the keys of address {address_id}"
+                        ),
+                        None => "its passphrase does not name the key it is for".to_string(),
+                    },
+                ),
+            }
+        }
+    };
+    Finding {
+        level,
+        label,
+        detail,
+    }
+}
+
+fn with_primary(primary: bool, detail: String) -> String {
+    if primary {
+        format!("primary, {detail}")
+    } else {
+        detail
+    }
+}
+
+/// The start of a Proton key ID: enough to tell keys apart and to find them
+/// in the daemon log, which prints the whole ID.
+fn short(id: &str) -> String {
+    match id.char_indices().nth(8) {
+        Some((end, _)) => format!("{}…", &id[..end]),
+        None => id.to_string(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use proton_sdk::account::AddressReport;
+    use proton_sdk::ids::{AddressKeyId, UserKeyId};
+
+    fn user_key(id: &str, active: bool, unlocks: bool, pgp: &str) -> UserKeyReport {
+        UserKeyReport {
+            id: UserKeyId::new(id),
+            primary: active,
+            active,
+            unlocks,
+            error: (!unlocks).then(|| "unlock: wrong passphrase".to_string()),
+            key_ids: vec![pgp.to_string()],
+        }
+    }
+
+    fn address_key(id: &str, primary: bool, token_for: &str, pgp: &str) -> AddressKeyReport {
+        AddressKeyReport {
+            id: AddressKeyId::new(id),
+            primary,
+            active: true,
+            token_recipients: Some(vec![Some(token_for.to_string())]),
+            unlocks: token_for == "u1",
+            error: (token_for != "u1").then(|| "token: failed to decrypt: missing key".to_string()),
+            key_ids: vec![pgp.to_string()],
+        }
+    }
+
+    /// The account in #40, as far as its log shows: the primary address key
+    /// opens, an older one does not, and My Files is encrypted to the older one.
+    fn report(stranded_token_for: &str) -> KeyReport {
+        KeyReport {
+            user_keys: vec![
+                user_key("UserKeyOne-123", true, true, "u1"),
+                user_key("UserKeyTwo-456", false, true, "u2"),
+            ],
+            addresses: vec![AddressReport {
+                id: AddressId::new("address-1"),
+                email: "user@proton.me".to_string(),
+                keys: vec![
+                    address_key("AddrKeyNew-789", true, "u1", "a1"),
+                    address_key("AddrKeyOld-000", false, stranded_token_for, "a2"),
+                ],
+            }],
+        }
+    }
+
+    #[test]
+    fn a_stranded_address_key_is_traced_to_the_inactive_account_key() {
+        let report = report("u2");
+        let share = Ok((AddressId::new("address-1"), vec![Some("a2".to_string())]));
+        let findings = findings(&report, &share);
+
+        assert_eq!(findings[0].detail, "primary, opens");
+        assert_eq!(findings[1].detail, "inactive, opens with your password");
+        assert_eq!(findings[2].level, Level::Ok);
+        assert_eq!(findings[3].level, Level::Warn);
+        assert_eq!(findings[3].label, "user@proton.me key AddrKeyO…");
+        assert_eq!(
+            findings[3].detail,
+            "does not open: its token is for inactive account key UserKeyT…, which opens with your password"
+        );
+        assert_eq!(findings[4].level, Level::Fail);
+        assert_eq!(
+            findings[4].detail,
+            "encrypted to user@proton.me key AddrKeyO…, which does not open"
+        );
+    }
+
+    #[test]
+    fn a_token_for_a_key_the_account_does_not_list_says_so() {
+        let report = report("ffff");
+        let detail = &findings(&report, &Err("offline".to_string()))[3].detail;
+        assert_eq!(
+            detail,
+            "does not open: its token is for key ffff, which is none of your account keys"
+        );
+    }
+
+    #[test]
+    fn a_share_that_opens_and_one_that_cannot_be_read() {
+        let report = report("u2");
+        let open = Ok((AddressId::new("address-1"), vec![Some("a1".to_string())]));
+        let last = findings(&report, &open).pop().unwrap();
+        assert_eq!(last.level, Level::Ok);
+        assert_eq!(
+            last.detail,
+            "encrypted to user@proton.me key AddrKeyN…, which opens"
+        );
+
+        let last = findings(&report, &Err("offline".to_string()))
+            .pop()
+            .unwrap();
+        assert_eq!(last.level, Level::Warn);
+        assert_eq!(last.detail, "could not be read: offline");
+    }
+}

crates/pdfs-core/src/lib.rs

@@ -10,9 +10,13 @@ pub mod config;
 pub mod control;
 pub mod db;
 pub mod error;
+pub mod exiftime;
 pub mod kernelkey;
+pub mod keycheck;
 pub mod localindex;
 pub mod menu;
+pub mod mountfail;
+pub mod mountpoint;
 pub mod mounts;
 pub mod opener;
 pub mod places;
@@ -23,8 +27,11 @@ pub mod service;
 pub mod shell;
 pub mod similar;
 pub mod syncignore;
+pub mod syncroot;
 pub mod takeout;
+pub mod timestamp;
 pub mod tray;
+pub mod update;
 
 pub use access::{Access, access_for, perm_bits};
 pub use error::{CoreError, CoreResult, Error, Result};

crates/pdfs-core/src/localindex.rs

@@ -42,7 +42,7 @@ const SKIP_PATH_SUFFIXES: &[&str] = &["go/pkg/mod"];
 
 /// Hard cap on indexed entries, so a pathological home directory cannot grow the
 /// database without bound. Reaching it stops the walk early.
-const MAX_ENTRIES: usize = 400_000;
+pub const MAX_ENTRIES: usize = 400_000;
 
 /// Rows handed to the sink at a time. Large enough that the per-transaction cost
 /// amortises, small enough that the writer lock is released often (FUSE

crates/pdfs-core/src/mountfail.rs

@@ -0,0 +1,89 @@
+//! Why the daemon's mount keeps failing, for the front ends to read.
+//!
+//! The control socket opens only once a mount has succeeded, so a daemon whose
+//! mount fails on every try had no way to say why. The app and the tray showed
+//! "Connecting…" for days while the reason sat in the journal (`docs/BUGS.md`
+//! B263). The daemon now writes its last failure to a small file in the state
+//! directory, next to the control socket, and removes it once a mount is up.
+
+use std::path::{Path, PathBuf};
+
+use serde::{Deserialize, Serialize};
+
+/// The file's name inside the state directory.
+const FILE_NAME: &str = "mount-failure.json";
+
+/// The last failed mount attempt.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+pub struct MountFailure {
+    /// The error, in English, as the journal has it.
+    pub error: String,
+    /// Unix seconds of the first failure in this run of failures.
+    pub since: i64,
+    /// Failed attempts in a row.
+    pub attempts: u32,
+    /// Unix seconds of the next attempt.
+    pub next_attempt: i64,
+    /// Set when the mount was refused because the folder already has files in
+    /// it, so the app can explain that in the user's language. Absent in a
+    /// file an older daemon wrote.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub not_empty: Option<crate::mountpoint::NotEmpty>,
+}
+
+/// Where the failure is kept for the state directory `state_dir`.
+pub fn path(state_dir: &Path) -> PathBuf {
+    state_dir.join(FILE_NAME)
+}
+
+/// Record `failure`, replacing the one before it. Written to a temporary file
+/// and renamed, so a reader never sees half of it.
+pub fn record(state_dir: &Path, failure: &MountFailure) -> std::io::Result<()> {
+    let json = serde_json::to_vec(failure).map_err(std::io::Error::other)?;
+    let tmp = state_dir.join(format!("{FILE_NAME}.tmp"));
+    std::fs::write(&tmp, json)?;
+    std::fs::rename(&tmp, path(state_dir))
+}
+
+/// Forget the failure: a mount is up, or a new daemon has started.
+pub fn clear(state_dir: &Path) {
+    let _ = std::fs::remove_file(path(state_dir));
+}
+
+/// The recorded failure, if there is one and it can be read.
+pub fn read(state_dir: &Path) -> Option<MountFailure> {
+    let bytes = std::fs::read(path(state_dir)).ok()?;
+    serde_json::from_slice(&bytes).ok()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_recorded_failure_reads_back_until_cleared() {
+        let dir = std::env::temp_dir().join(format!("pdfs-mountfail-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).unwrap();
+        assert_eq!(read(&dir), None);
+        let failure = MountFailure {
+            error: "fetch My Files root: missing key".into(),
+            since: 1_700_000_000,
+            attempts: 3,
+            next_attempt: 1_700_000_040,
+            not_empty: None,
+        };
+        record(&dir, &failure).unwrap();
+        assert_eq!(read(&dir), Some(failure));
+        clear(&dir);
+        assert_eq!(read(&dir), None);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn a_failure_an_older_daemon_wrote_still_reads() {
+        let old = r#"{"error":"missing key","since":1,"attempts":2,"next_attempt":3}"#;
+        let failure: MountFailure = serde_json::from_str(old).unwrap();
+        assert_eq!(failure.not_empty, None);
+        assert_eq!(failure.attempts, 2);
+    }
+}

crates/pdfs-core/src/mountpoint.rs

@@ -0,0 +1,147 @@
+//! Whether a folder can take the My files mount without hiding anything.
+//!
+//! FUSE mounts over a folder that already has files in it without a word. The
+//! files then sit under the mount, out of sight: not uploaded, and back only
+//! once the service stops, so they look deleted (`docs/BUGS.md` B277, #67).
+//! The daemon refuses such a folder, and the app refuses it when it is picked.
+
+use std::path::{Path, PathBuf};
+
+use serde::{Deserialize, Serialize};
+
+/// The file system type the kernel reports for this client's own mounts.
+pub const OWN_FS_TYPE: &str = "fuse.protondrive";
+
+/// How many of a folder's entries an error names.
+const NAMED_ENTRIES: usize = 3;
+
+/// A folder that already has something in it.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+pub struct NotEmpty {
+    /// The folder.
+    pub path: PathBuf,
+    /// The first few names in it, sorted.
+    pub entries: Vec<String>,
+    /// How many entries it has in all.
+    pub count: usize,
+}
+
+impl std::fmt::Display for NotEmpty {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{} is not empty (holds ", self.path.display())?;
+        write!(f, "{}", self.entries.join(", "))?;
+        let rest = self.count.saturating_sub(self.entries.len());
+        if rest > 0 {
+            write!(f, " and {rest} more")?;
+        }
+        write!(
+            f,
+            "); My files would hide those files. Move them out, or choose another folder for My files"
+        )
+    }
+}
+
+impl std::error::Error for NotEmpty {}
+
+/// What is in `dir`, if anything. A folder that does not exist yet is empty.
+/// Hidden entries count: a `.directory` or a `.Trash-1000` hidden under the
+/// mount is as lost as any other file.
+pub fn not_empty(dir: &Path) -> std::io::Result<Option<NotEmpty>> {
+    let read = match std::fs::read_dir(dir) {
+        Ok(read) => read,
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(None),
+        Err(e) => return Err(e),
+    };
+    let mut names = read
+        .map(|entry| entry.map(|entry| entry.file_name().to_string_lossy().into_owned()))
+        .collect::<std::io::Result<Vec<_>>>()?;
+    if names.is_empty() {
+        return Ok(None);
+    }
+    names.sort();
+    let count = names.len();
+    names.truncate(NAMED_ENTRIES);
+    Ok(Some(NotEmpty {
+        path: dir.to_path_buf(),
+        entries: names,
+        count,
+    }))
+}
+
+/// The file system type mounted at `path`, as `/proc/self/mountinfo` names it
+/// (`ext4`, `fuse.protondrive`, …), or `None` when nothing is mounted there.
+pub fn mounted_fs_type(path: &Path) -> Option<String> {
+    let wanted = path.canonicalize().ok()?;
+    let mounts = std::fs::read_to_string("/proc/self/mountinfo").ok()?;
+    mounts
+        .lines()
+        .filter_map(|line| {
+            let fields: Vec<_> = line.split_whitespace().collect();
+            let separator = fields.iter().position(|field| *field == "-")?;
+            let encoded = *fields.get(4)?;
+            let decoded = encoded.replace("\\040", " ").replace("\\011", "\t");
+            let mountpoint = PathBuf::from(decoded);
+            if mountpoint.canonicalize().ok()? == wanted {
+                Some(fields.get(separator + 1)?.to_string())
+            } else {
+                None
+            }
+        })
+        .next()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn temp_dir(name: &str) -> PathBuf {
+        let dir =
+            std::env::temp_dir().join(format!("pdfs-mountpoint-{name}-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&dir);
+        std::fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    #[test]
+    fn an_empty_or_missing_folder_takes_the_mount() {
+        let dir = temp_dir("empty");
+        assert_eq!(not_empty(&dir).unwrap(), None);
+        assert_eq!(not_empty(&dir.join("missing")).unwrap(), None);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn a_folder_with_files_is_refused_and_named() {
+        let dir = temp_dir("files");
+        for name in ["report.pdf", "Notes", ".directory", "zeta.txt"] {
+            std::fs::write(dir.join(name), b"x").unwrap();
+        }
+        let found = not_empty(&dir).unwrap().expect("must refuse");
+        assert_eq!(found.count, 4);
+        assert_eq!(found.entries, [".directory", "Notes", "report.pdf"]);
+        let message = found.to_string();
+        assert!(message.contains("is not empty"), "{message}");
+        assert!(
+            message.contains(".directory, Notes, report.pdf and 1 more"),
+            "{message}"
+        );
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn a_hidden_file_alone_is_enough_to_refuse() {
+        let dir = temp_dir("hidden");
+        std::fs::write(dir.join(".Trash-1000"), b"").unwrap();
+        let found = not_empty(&dir).unwrap().expect("must refuse");
+        assert_eq!(found.count, 1);
+        assert!(!found.to_string().contains("more"));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn a_plain_folder_is_not_a_mount() {
+        let dir = temp_dir("plain");
+        assert_eq!(mounted_fs_type(&dir), None);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}

crates/pdfs-core/src/mounts.rs

@@ -81,6 +81,8 @@ pub enum MountKind {
     MyFiles,
     /// A folder owned by this machine's Proton Drive device.
     Device { sync_folder_id: i64 },
+    /// A real local mirror of an existing My files folder.
+    Attached { sync_folder_id: i64 },
     /// A future standalone mount rooted at a node shared with this account.
     Shared { share_root_uid: String },
 }
@@ -88,8 +90,8 @@ pub enum MountKind {
 /// One local Proton Drive location as exposed over the control protocol.
 #[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct MountSpec {
-    /// Presentation-row id. Device actions use the `sync_folder_id` carried by
-    /// [`MountKind::Device`], not this id.
+    /// Presentation-row id. Synced-folder actions use the `sync_folder_id`
+    /// carried by [`MountKind::Device`] or [`MountKind::Attached`], not this id.
     pub id: i64,
     pub kind: MountKind,
     pub local_path: String,

crates/pdfs-core/src/opener.rs

@@ -27,6 +27,7 @@ use std::os::unix::process::CommandExt;
 use std::path::Path;
 use std::process::{Command, Stdio};
 
+use crate::control::is_video_file_name;
 use serde::{Deserialize, Serialize};
 
 /// Environment override for the terminal used by `"terminal": true` rules.
@@ -108,11 +109,12 @@ impl OpenWith {
     /// a Markdown file). The rules are about *what the user opened*, so the
     /// caller passes that name and the argv still gets the real path.
     pub fn command_for_named(&self, path: &Path, name: &str, is_dir: bool) -> Vec<String> {
+        let kind = Kind::of(path, name, is_dir);
         for rule in &self.rules {
             if rule.command.is_empty() {
                 continue;
             }
-            if !rule.patterns.iter().any(|p| matches(p, name, is_dir)) {
+            if !rule.patterns.iter().any(|p| matches(p, name, kind)) {
                 continue;
             }
             let argv = expand(&rule.command, path);
@@ -189,11 +191,21 @@ fn spawn(argv: &[String], path: &Path) {
         .stderr(Stdio::null())
         .process_group(0)
         .spawn();
-    if let Err(e) = spawned {
-        tracing::error!(command = ?argv, "open failed: {e}");
+    match spawned {
+        Ok(child) => reap(child),
+        Err(e) => tracing::error!(command = ?argv, "open failed: {e}"),
     }
 }
 
+/// Wait for `child` on a thread of its own. A child nobody waits for stays a
+/// zombie for as long as its parent lives, which for the app and the tray is
+/// the whole session.
+pub fn reap(mut child: std::process::Child) {
+    std::thread::spawn(move || {
+        let _ = child.wait();
+    });
+}
+
 /// [`open`] with the policy from the user's `config.json`, read once per
 /// process. For callers that open the occasional path and have no reason to
 /// carry a policy around; long-lived windows should hold their own copy.
@@ -315,16 +327,46 @@ fn expand_env(token: &str) -> Option<String> {
     value.filter(|v| !v.is_empty())
 }
 
+/// What is being opened, as far as the `@class` patterns care.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum Kind {
+    Dir,
+    Video,
+    File,
+}
+
+impl Kind {
+    /// `.ts` names TypeScript and MPEG transport streams alike, so for that
+    /// one extension the size on disk decides (see
+    /// [`is_video_file_name`](crate::control::is_video_file_name)). No other
+    /// name costs a `stat`.
+    fn of(path: &Path, name: &str, is_dir: bool) -> Kind {
+        if is_dir {
+            return Kind::Dir;
+        }
+        let size = extension(name)
+            .eq_ignore_ascii_case("ts")
+            .then(|| std::fs::metadata(path).ok().map(|meta| meta.len()))
+            .flatten();
+        if is_video_file_name(name, size) {
+            Kind::Video
+        } else {
+            Kind::File
+        }
+    }
+}
+
 /// Whether `pattern` — a glob or an `@class` — matches this name.
-fn matches(pattern: &str, name: &str, is_dir: bool) -> bool {
+fn matches(pattern: &str, name: &str, kind: Kind) -> bool {
     let name_lower = name.to_lowercase();
+    let file = kind == Kind::File;
     match pattern.to_lowercase().as_str() {
         "@any" => true,
-        "@dir" => is_dir,
-        "@text" => !is_dir && class_text(&name_lower),
-        "@document" => !is_dir && class_document(&name_lower),
-        "@image" => !is_dir && class_image(&name_lower),
-        "@media" => !is_dir && class_media(&name_lower),
+        "@dir" => kind == Kind::Dir,
+        "@text" => file && class_text(&name_lower),
+        "@document" => file && class_document(&name_lower),
+        "@image" => file && class_image(&name_lower),
+        "@media" => kind == Kind::Video || (file && class_media(&name_lower)),
         other if other.starts_with('@') => false,
         other => glob_match(other, &name_lower),
     }
@@ -472,6 +514,21 @@ fn glob_match(pattern: &str, name: &str) -> bool {
 mod tests {
     use super::*;
 
+    #[test]
+    fn a_reaped_child_does_not_stay_a_zombie() {
+        let child = std::process::Command::new("true").spawn().unwrap();
+        let proc_entry = std::path::PathBuf::from(format!("/proc/{}", child.id()));
+        reap(child);
+        let deadline = std::time::Instant::now() + std::time::Duration::from_secs(5);
+        while proc_entry.exists() && std::time::Instant::now() < deadline {
+            std::thread::sleep(std::time::Duration::from_millis(10));
+        }
+        assert!(
+            !proc_entry.exists(),
+            "the child is still in the process table"
+        );
+    }
+
     fn rule(patterns: &[&str], command: &[&str], terminal: bool) -> OpenRule {
         OpenRule {
             patterns: patterns.iter().map(|p| (*p).to_string()).collect(),
@@ -508,6 +565,37 @@ mod tests {
         );
     }
 
+    #[test]
+    fn a_ts_file_opens_as_media_or_text_by_its_size() {
+        let policy = OpenWith {
+            terminal: Some(vec!["alacritty".into(), "-e".into()]),
+            default: None,
+            rules: vec![
+                rule(&["@text"], &["nvim"], true),
+                rule(&["@media"], &["mpv"], false),
+            ],
+        };
+        let dir = std::env::temp_dir().join(format!("pdfs-opener-ts-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).unwrap();
+        let source = dir.join("blob-source");
+        std::fs::write(&source, "export const answer = 42;\n").unwrap();
+        let recording = dir.join("blob-recording");
+        std::fs::File::create(&recording)
+            .unwrap()
+            .set_len(crate::control::TS_VIDEO_MIN_BYTES)
+            .unwrap();
+
+        let source_argv = policy.command_for_named(&source, "app.ts", false);
+        let recording_argv = policy.command_for_named(&recording, "recording.ts", false);
+        // A file that is not on this machine yet has no size to go by.
+        let unknown_argv = policy.command_for_named(&dir.join("missing"), "recording.ts", false);
+        std::fs::remove_dir_all(&dir).unwrap();
+
+        assert_eq!(source_argv[..3], ["alacritty", "-e", "nvim"]);
+        assert_eq!(recording_argv[0], "mpv");
+        assert_eq!(unknown_argv[0], "mpv");
+    }
+
     #[test]
     fn an_empty_policy_is_xdg_open() {
         let policy = OpenWith::default();

crates/pdfs-core/src/profile.rs

@@ -19,9 +19,31 @@ use serde::{Deserialize, Serialize};
 
 use crate::mounts::MountMode;
 
-/// File name of the profile.
+/// File name of the profile clients before 3.5.0 wrote, one per device.
+///
+/// Read, never written: two computers sharing a device each overwrote the
+/// other's. See [`profile_file_name`].
 pub const PROFILE_FILE_NAME: &str = "profile.json";
 
+/// File name of one machine's profile: `profile-<machine id>.json`.
+///
+/// One per machine, because several computers may sync into one device, and
+/// each describes its own arrangement. A single shared file went to whichever
+/// computer saved last.
+pub fn profile_file_name(machine_id: &str) -> String {
+    format!("profile-{machine_id}.json")
+}
+
+/// Whether `name` is a profile: [`PROFILE_FILE_NAME`] or one machine's
+/// [`profile_file_name`].
+pub fn is_profile_file_name(name: &str) -> bool {
+    name == PROFILE_FILE_NAME
+        || name
+            .strip_prefix("profile-")
+            .and_then(|rest| rest.strip_suffix(".json"))
+            .is_some_and(|id| !id.is_empty() && id.bytes().all(|b| b.is_ascii_alphanumeric()))
+}
+
 /// Folder, directly under the device root, that holds the profile.
 ///
 /// The API refuses `Cannot create file at the root of a device` (HTTP 422), so
@@ -74,6 +96,10 @@ pub struct Profile {
     /// Hostname of the machine that wrote it, so a restore prompt can say
     /// *"restore settings from laptop-xyz?"* rather than quoting a uid.
     pub hostname: String,
+    /// The writing machine's id, as in its [`profile_file_name`]. `None` in a
+    /// profile written before 3.5.0.
+    #[serde(default)]
+    pub machine_id: Option<String>,
     /// When it was written, epoch seconds.
     pub saved_at: i64,
     #[serde(default)]
@@ -92,6 +118,25 @@ pub struct Profile {
     pub mountpoint: Option<String>,
 }
 
+/// The saved arrangement of the folder with uid `remote_uid`, from the
+/// profiles of every computer that syncs the device.
+///
+/// The profile of the machine named `hostname` wins, since it describes this
+/// computer; otherwise the most recently saved one that has the folder.
+pub fn saved_folder<'a>(
+    profiles: &'a [Profile],
+    remote_uid: &str,
+    hostname: &str,
+) -> Option<&'a ProfileFolder> {
+    let holding = |p: &&'a Profile| p.folders.iter().any(|f| f.remote_uid == remote_uid);
+    let profile = profiles
+        .iter()
+        .filter(holding)
+        .find(|p| p.hostname == hostname)
+        .or_else(|| profiles.iter().filter(holding).max_by_key(|p| p.saved_at))?;
+    profile.folders.iter().find(|f| f.remote_uid == remote_uid)
+}
+
 impl Profile {
     /// Parse a profile document, refusing one written by a newer client.
     pub fn parse(bytes: &[u8]) -> Result<Self, String> {
@@ -122,6 +167,7 @@ mod tests {
             version: PROFILE_VERSION,
             device_uid: "dev-1".to_string(),
             hostname: "laptop-xyz".to_string(),
+            machine_id: Some("0123456789abcdef0123456789abcdef".to_string()),
             saved_at: 1_700_000_000,
             folders: vec![ProfileFolder {
                 remote_uid: "vol~link".to_string(),
@@ -219,6 +265,52 @@ mod tests {
         assert!(p.ignore_patterns.is_none());
     }
 
+    #[test]
+    fn a_profile_name_is_the_legacy_one_or_one_per_machine() {
+        assert!(is_profile_file_name(PROFILE_FILE_NAME));
+        let name = profile_file_name("0123456789abcdef0123456789abcdef");
+        assert_eq!(name, "profile-0123456789abcdef0123456789abcdef.json");
+        assert!(is_profile_file_name(&name));
+        assert!(!is_profile_file_name("profile-.json"));
+        assert!(!is_profile_file_name("profile-a/b.json"));
+        assert!(!is_profile_file_name("profile (1).json"));
+        assert!(!is_profile_file_name("notes.json"));
+    }
+
+    /// A profile written before 3.5.0 has no machine id and still parses.
+    #[test]
+    fn a_profile_without_a_machine_id_parses() {
+        let json = br#"{"version":1,"device_uid":"d","hostname":"h","saved_at":0}"#;
+        assert_eq!(Profile::parse(json).unwrap().machine_id, None);
+    }
+
+    /// Several computers sync one device, each with its own profile. This
+    /// computer's own wins, then the newest that has the folder.
+    #[test]
+    fn the_saved_folder_comes_from_this_computer_then_the_newest_profile() {
+        let profile = |hostname: &str, saved_at: i64, path: &str| Profile {
+            hostname: hostname.to_string(),
+            saved_at,
+            folders: vec![ProfileFolder {
+                remote_uid: "vol~docs".to_string(),
+                local_path: path.to_string(),
+                mode: MountMode::Mirror,
+            }],
+            ..sample()
+        };
+        let profiles = vec![
+            profile("desktop", 10, "/home/a/Docs"),
+            profile("laptop", 5, "/home/b/Docs"),
+            profile("old", 1, "/home/c/Docs"),
+        ];
+        let path =
+            |host: &str| saved_folder(&profiles, "vol~docs", host).map(|f| f.local_path.as_str());
+        assert_eq!(path("laptop"), Some("/home/b/Docs"));
+        assert_eq!(path("new-machine"), Some("/home/a/Docs"));
+        assert_eq!(saved_folder(&profiles, "vol~other", "laptop"), None);
+        assert_eq!(saved_folder(&[], "vol~docs", "laptop"), None);
+    }
+
     #[test]
     fn future_version_is_refused() {
         let mut p = sample();

crates/pdfs-core/src/shell.rs

@@ -23,6 +23,11 @@ const SCRIPTS: [(&str, &str); 2] = [
 /// `NAUTILUS_SCRIPT_SELECTED_FILE_PATHS`; the positional args carry the same
 /// selection when the script runs on a local (non-URI) folder, so we prefer the
 /// environment and fall back to `"$@"` for the Nemo/Caja variants.
+///
+/// The `--` keeps a file named like an option, such as `--json`, a path. A
+/// name with a newline in it still arrives split in two from Nautilus, whose
+/// list is newline-separated; `pdfs` then fails on both halves, which touches
+/// nothing.
 fn script_body(subcommand: &str) -> String {
     format!(
         "#!/bin/sh\n\
@@ -41,7 +46,7 @@ fn script_body(subcommand: &str) -> String {
          \n\
          printf '%s' \"$paths\" | while IFS= read -r path; do\n\
          \x20   [ -n \"$path\" ] || continue\n\
-         \x20   pdfs {subcommand} \"$path\" || exit 1\n\
+         \x20   pdfs {subcommand} -- \"$path\" || exit 1\n\
          done\n"
     )
 }
@@ -95,3 +100,13 @@ fn write_scripts(dir: &PathBuf) -> io::Result<()> {
     tracing::debug!("installed file-manager scripts in {dir:?}");
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::script_body;
+
+    #[test]
+    fn the_script_ends_options_before_each_path() {
+        assert!(script_body("pin").contains(r#"pdfs pin -- "$path""#));
+    }
+}

crates/pdfs-core/src/syncroot.rs

@@ -0,0 +1,209 @@
+//! Which local folders may become a sync root.
+//!
+//! A mirror uploads everything under its root and deletes what Drive deleted,
+//! so a root that holds more than the user meant is dangerous. `$HOME` takes
+//! the decrypted content cache, `cache.db` and `~/.ssh` up to Drive, and walks
+//! into the mount, which downloads the whole Drive only to upload it again.
+//! Every place a root is added or restored goes through [`problem`].
+
+use std::path::{Component, Path, PathBuf};
+
+use crate::config::{AppConfig, AppDirs};
+
+/// The paths a sync root must stay clear of.
+#[derive(Debug, Clone, Default)]
+pub struct Reserved {
+    /// The user's home folder. A root may sit inside it, not be it or above it.
+    pub home: Option<PathBuf>,
+    /// The Proton Drive mount.
+    pub mountpoint: Option<PathBuf>,
+    /// This app's own configuration, state and cache folders.
+    pub app_dirs: Vec<PathBuf>,
+}
+
+impl Reserved {
+    /// The reserved paths of this user and `config`, resolved like a root.
+    pub fn current(config: &AppConfig) -> Self {
+        let Ok(dirs) = AppDirs::new() else {
+            return Self::default();
+        };
+        let resolved = |path: PathBuf| resolve(&path).unwrap_or(path);
+        let mut app_dirs = vec![dirs.state_dir(), dirs.cache_dir()];
+        if let Some(config_dir) = dirs.config_path().parent() {
+            app_dirs.push(config_dir.to_path_buf());
+        }
+        Self {
+            home: dirs.home_dir().map(resolved),
+            mountpoint: Some(resolved(dirs.resolved_mountpoint(config))),
+            app_dirs: app_dirs.into_iter().map(resolved).collect(),
+        }
+    }
+}
+
+/// `path` as a root is compared: absolute, with symlinks resolved as far as the
+/// path exists. A folder a restore is about to create does not exist yet, so
+/// the part past the deepest existing folder is kept as written.
+///
+/// A `..` is refused rather than resolved: before a symlink it means something
+/// else than after it, and a path recorded on another machine has no business
+/// holding one.
+pub fn resolve(path: &Path) -> Result<PathBuf, String> {
+    if !path.is_absolute() {
+        return Err(format!("{} is not an absolute path", path.display()));
+    }
+    if path.components().any(|c| c == Component::ParentDir) {
+        return Err(format!("{} goes up with `..`", path.display()));
+    }
+    let mut existing = path.to_path_buf();
+    let mut rest = Vec::new();
+    loop {
+        match existing.canonicalize() {
+            Ok(canonical) => {
+                return Ok(rest
+                    .into_iter()
+                    .rev()
+                    .fold(canonical, |path: PathBuf, part| path.join(part)));
+            }
+            Err(_) => {
+                let Some(name) = existing.file_name().map(|n| n.to_os_string()) else {
+                    return Ok(path.to_path_buf());
+                };
+                rest.push(name);
+                if !existing.pop() {
+                    return Ok(path.to_path_buf());
+                }
+            }
+        }
+    }
+}
+
+/// Why `root` cannot be synced, or `None` when it can. `root` is resolved
+/// ([`resolve`]); `others` are the roots already synced.
+pub fn problem(root: &Path, others: &[PathBuf], reserved: &Reserved) -> Option<String> {
+    let shown = root.display();
+    if root.parent().is_none() {
+        return Some(format!("{shown} is the root of the file system"));
+    }
+    if let Some(home) = &reserved.home {
+        if root == home {
+            return Some(format!(
+                "{shown} is your home folder; pick a folder inside it"
+            ));
+        }
+        if home.starts_with(root) {
+            return Some(format!("{shown} holds your home folder"));
+        }
+    }
+    if let Some(mountpoint) = &reserved.mountpoint
+        && overlaps(root, mountpoint)
+    {
+        return Some(format!(
+            "{shown} overlaps the Proton Drive folder {}",
+            mountpoint.display()
+        ));
+    }
+    if let Some(dir) = reserved.app_dirs.iter().find(|dir| overlaps(root, dir)) {
+        return Some(format!(
+            "{shown} overlaps this app's own data in {}",
+            dir.display()
+        ));
+    }
+    if others.iter().any(|other| other == root) {
+        return Some(format!("{shown} is already synced"));
+    }
+    if let Some(other) = others.iter().find(|other| overlaps(root, other)) {
+        return Some(format!(
+            "{shown} overlaps the synced folder {}",
+            other.display()
+        ));
+    }
+    None
+}
+
+/// Whether one of `a` and `b` is the other or inside it.
+fn overlaps(a: &Path, b: &Path) -> bool {
+    a.starts_with(b) || b.starts_with(a)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn reserved() -> Reserved {
+        Reserved {
+            home: Some("/home/u".into()),
+            mountpoint: Some("/home/u/ProtonDrive".into()),
+            app_dirs: vec![
+                "/home/u/.local/state/proton-drive-linux".into(),
+                "/home/u/.cache/proton-drive-linux".into(),
+                "/home/u/.config/proton-drive-linux".into(),
+            ],
+        }
+    }
+
+    fn refused(root: &str, others: &[&str]) -> bool {
+        let others: Vec<PathBuf> = others.iter().map(PathBuf::from).collect();
+        problem(Path::new(root), &others, &reserved()).is_some()
+    }
+
+    #[test]
+    fn a_folder_inside_home_can_be_synced() {
+        assert!(!refused("/home/u/Documents", &[]));
+        assert!(!refused("/home/u/Pictures", &["/home/u/Documents"]));
+        assert!(!refused("/mnt/data/photos", &[]));
+    }
+
+    #[test]
+    fn the_file_system_root_home_and_its_parents_are_refused() {
+        assert!(refused("/", &[]));
+        assert!(refused("/home/u", &[]));
+        assert!(refused("/home", &[]));
+    }
+
+    #[test]
+    fn the_mount_and_the_apps_own_data_are_refused_either_way_round() {
+        assert!(refused("/home/u/ProtonDrive", &[]));
+        assert!(refused("/home/u/ProtonDrive/Documents", &[]));
+        assert!(refused("/home/u/.cache", &[]));
+        assert!(refused(
+            "/home/u/.local/state/proton-drive-linux/staging",
+            &[]
+        ));
+        assert!(refused("/home/u/.config", &[]));
+    }
+
+    #[test]
+    fn a_root_inside_or_around_another_root_is_refused() {
+        assert!(refused("/home/u/Documents", &["/home/u/Documents"]));
+        assert!(refused("/home/u/Documents/Work", &["/home/u/Documents"]));
+        assert!(refused("/home/u/stuff", &["/home/u/stuff/Documents"]));
+        // A shared prefix of characters is not a shared folder.
+        assert!(!refused("/home/u/Documents2", &["/home/u/Documents"]));
+    }
+
+    #[test]
+    fn a_path_that_goes_up_or_is_relative_does_not_resolve() {
+        assert!(resolve(Path::new("/home/u/../../etc")).is_err());
+        assert!(resolve(Path::new("Documents")).is_err());
+    }
+
+    #[test]
+    fn a_folder_still_to_be_created_resolves_under_its_existing_parent() {
+        let base = std::env::temp_dir().join(format!("pdfs-syncroot-{}", std::process::id()));
+        std::fs::create_dir_all(&base).unwrap();
+        let canonical = base.canonicalize().unwrap();
+        assert_eq!(
+            resolve(&base.join("new/inner")).unwrap(),
+            canonical.join("new/inner")
+        );
+        let link = base.join("link");
+        let _ = std::fs::remove_file(&link);
+        std::os::unix::fs::symlink(&canonical, &link).unwrap();
+        assert_eq!(
+            resolve(&link.join("later")).unwrap(),
+            canonical.join("later"),
+            "a symlink is followed to where it points"
+        );
+        std::fs::remove_dir_all(&base).unwrap();
+    }
+}

crates/pdfs-core/src/takeout.rs

@@ -346,6 +346,11 @@ fn assemble(entries: Vec<RawEntry>, sidecars: &HashMap<String, Vec<u8>>) -> Take
             .insert(file.to_string(), body);
     }
 
+    let indexes: HashMap<&str, SidecarIndex<'_>> = per_folder_sidecars
+        .iter()
+        .map(|(folder, in_folder)| (folder.as_str(), SidecarIndex::new(in_folder)))
+        .collect();
+
     let mut scan = TakeoutScan::default();
     let mut seen_albums: HashMap<String, ()> = HashMap::new();
 
@@ -364,9 +369,13 @@ fn assemble(entries: Vec<RawEntry>, sidecars: &HashMap<String, Vec<u8>>) -> Take
             continue;
         };
 
-        let sidecar = per_folder_sidecars
-            .get(&folder)
-            .and_then(|in_folder| find_sidecar(&file_name, in_folder))
+        let found = indexes
+            .get(folder.as_str())
+            .and_then(|index| find_sidecar(&file_name, index));
+        // An edited copy keeps its own name: the title is its original's.
+        let title_is_ours = found.is_some_and(|((rule, _), _)| rule != EDITED_COPY);
+        let sidecar = found
+            .map(|(_, body)| body)
             .and_then(|body| serde_json::from_slice::<PhotoSidecar>(body).ok())
             .unwrap_or_default();
 
@@ -388,6 +397,7 @@ fn assemble(entries: Vec<RawEntry>, sidecars: &HashMap<String, Vec<u8>>) -> Take
         let name = sidecar
             .title
             .as_deref()
+            .filter(|_| title_is_ours)
             .map(str::trim)
             .filter(|title| !title.is_empty() && same_extension(title, &file_name))
             .unwrap_or(&file_name)
@@ -598,7 +608,7 @@ pub fn capture_time_from_name(name: &str) -> Option<i64> {
 
 /// Days between 1970-01-01 and a proleptic-Gregorian date (Howard Hinnant's
 /// `days_from_civil`). Avoids pulling a date crate in for one conversion.
-fn days_from_civil(year: i64, month: i64, day: i64) -> i64 {
+pub(crate) fn days_from_civil(year: i64, month: i64, day: i64) -> i64 {
     let year = year - i64::from(month <= 2);
     let era = if year >= 0 { year } else { year - 399 } / 400;
     let year_of_era = year - era * 400;
@@ -627,17 +637,106 @@ fn swap_duplicate_marker(file_name: &str) -> Option<String> {
     Some(format!("{}{}{}", &file_name[..marker_start], tail, marker))
 }
 
-/// Find the sidecar belonging to `file_name` among the JSON files of its folder.
+/// How long Google lets a sidecar's file name get, `.json` included. A longer
+/// one is cut, into its suffix first and then into the photo name.
+const SIDECAR_NAME_CAP: usize = 51;
+
+/// The rank [`sidecar_rank`] gives an edited copy that shares its original's
+/// sidecar. Its date is the original's, but its name is its own.
+const EDITED_COPY: u8 = 4;
+
+/// The sidecars of one folder by their `.json`-stripped stem, so a photo is
+/// ranked only against those that can match it.
+///
+/// Every rule in [`sidecar_rank`] needs the stem to start with a prefix of the
+/// photo name that the name itself determines, and a sorted map finds the
+/// stems with a given prefix as one range. Ranking every photo against every
+/// sidecar instead took 27 s for a folder of 10,000 photos.
+struct SidecarIndex<'a> {
+    by_stem: BTreeMap<&'a str, Vec<(&'a str, &'a Vec<u8>)>>,
+}
+
+impl<'a> SidecarIndex<'a> {
+    fn new(in_folder: &'a BTreeMap<String, &'a Vec<u8>>) -> Self {
+        let mut by_stem: BTreeMap<&'a str, Vec<(&'a str, &'a Vec<u8>)>> = BTreeMap::new();
+        for (name, body) in in_folder {
+            by_stem
+                .entry(strip_json_suffix(name))
+                .or_default()
+                .push((name.as_str(), *body));
+        }
+        Self { by_stem }
+    }
+
+    /// Add every sidecar whose stem starts with `prefix` to `out`.
+    fn starting_with(&self, prefix: &str, out: &mut BTreeMap<&'a str, &'a Vec<u8>>) {
+        let from = (
+            std::ops::Bound::Included(prefix),
+            std::ops::Bound::Unbounded,
+        );
+        for (stem, sidecars) in self.by_stem.range::<str, _>(from) {
+            if !stem.starts_with(prefix) {
+                break;
+            }
+            out.extend(sidecars.iter().copied());
+        }
+    }
+
+    /// Add every sidecar whose stem is `head`, or starts with `head` and a `.`:
+    /// those that have `head` as a boundary ([`suffix_boundaries`]).
+    fn bounded_by(&self, head: &str, out: &mut BTreeMap<&'a str, &'a Vec<u8>>) {
+        if let Some(sidecars) = self.by_stem.get(head) {
+            out.extend(sidecars.iter().copied());
+        }
+        self.starting_with(&format!("{head}."), out);
+    }
+
+    /// Every sidecar [`sidecar_rank`] could match `file_name` to, by name. A
+    /// superset: each one is still ranked.
+    fn candidates(&self, file_name: &str) -> BTreeMap<&'a str, &'a Vec<u8>> {
+        let mut out = BTreeMap::new();
+        // Rules 0 and 2: the stem starts with the name, or with its swapped form.
+        self.starting_with(file_name, &mut out);
+        if let Some(swapped) = swap_duplicate_marker(file_name) {
+            self.starting_with(&swapped, &mut out);
+        }
+        // Rule 1: the stem of `A(N).B` starts with `A.B(N)`, so with `A.`.
+        for (paren, _) in file_name.match_indices('(') {
+            self.starting_with(&format!("{}.", &file_name[..paren]), &mut out);
+        }
+        // Rule 3: a boundary of the stem is a prefix of the name.
+        for end in file_name
+            .char_indices()
+            .map(|(index, _)| index)
+            .skip(1)
+            .chain([file_name.len()])
+        {
+            self.bounded_by(&file_name[..end], &mut out);
+        }
+        // Rule 4: `<original>-<word>.<ext>` has `<original>.<ext>` as a boundary.
+        if let Some((_, extension)) = file_name.rsplit_once('.') {
+            for (dash, _) in file_name.match_indices('-') {
+                self.bounded_by(&format!("{}.{extension}", &file_name[..dash]), &mut out);
+            }
+        }
+        out
+    }
+}
+
+/// Find the sidecar belonging to `file_name` among the JSON files of its folder,
+/// with the rank it matched at.
 ///
 /// Tried in order of confidence: the exact name, the `(N)`-swapped name, an
-/// unknown trailing suffix, then a prefix match for the case where truncation
-/// cut into the photo name itself. The best-ranked candidate in the folder wins.
+/// unknown trailing suffix, a prefix match for the case where truncation cut
+/// into the photo name itself, and last an edited copy's original. The
+/// best-ranked candidate in the folder wins; of equal ranks, the first by
+/// sidecar name.
 fn find_sidecar<'a>(
     file_name: &str,
-    in_folder: &BTreeMap<String, &'a Vec<u8>>,
-) -> Option<&'a Vec<u8>> {
+    index: &SidecarIndex<'a>,
+) -> Option<((u8, usize), &'a Vec<u8>)> {
     let mut best: Option<((u8, usize), &'a Vec<u8>)> = None;
-    for (sidecar_name, body) in in_folder {
+    for (sidecar_name, body) in index.candidates(file_name) {
         let Some(rank) = sidecar_rank(strip_json_suffix(sidecar_name), file_name) else {
             continue;
         };
@@ -645,7 +744,7 @@ fn find_sidecar<'a>(
             best = Some((rank, body));
         }
     }
-    best.map(|(_, body)| body)
+    best
 }
 
 /// How well a sidecar's `.json`-stripped `stem` matches `file_name`, as a sort
@@ -683,19 +782,44 @@ fn sidecar_rank(stem: &str, file_name: &str) -> Option<(u8, usize)> {
     }
     // 3 — truncation ate into the photo name itself, leaving only a prefix of
     // it. Every suffix boundary in the stem is tried, so this holds for a
-    // localized suffix too; the longest surviving prefix wins, because a folder
-    // with `IMG_1.jpg` and `IMG_12.jpg` must not let the shorter stem claim the
-    // longer photo.
-    let mut longest: Option<usize> = None;
-    for head in suffix_boundaries(stem) {
-        if !head.is_empty()
-            && file_name.starts_with(head)
-            && longest.is_none_or(|len| head.len() > len)
-        {
-            longest = Some(head.len());
+    // localized suffix too; the longest surviving prefix wins.
+    //
+    // Only for a sidecar whose name is as long as Google lets one get: a name
+    // that short of the cap was not cut, so a prefix of it is the name of a
+    // different photo. Without this, `IMG_1.jpg`'s sidecar gave its name and
+    // date to an `IMG_12.jpg` that had none (`docs/BUGS.md` B225).
+    if stem.chars().count() + ".json".len() >= SIDECAR_NAME_CAP - 4 {
+        let mut longest: Option<usize> = None;
+        for head in suffix_boundaries(stem) {
+            if !head.is_empty()
+                && file_name.starts_with(head)
+                && longest.is_none_or(|len| head.len() > len)
+            {
+                longest = Some(head.len());
+            }
+        }
+        if let Some(len) = longest {
+            return Some((3, usize::MAX - len));
         }
     }
-    longest.map(|len| (3, usize::MAX - len))
+    // 4 — an edited copy, `IMG_1-edited.jpg` (the word is localized), which
+    // Google exports without a sidecar of its own next to `IMG_1.jpg`'s.
+    suffix_boundaries(stem)
+        .filter_map(|head| head.rsplit_once('.'))
+        .any(|(original, extension)| is_edited_copy_of(file_name, original, extension))
+        .then_some((EDITED_COPY, 0))
+}
+
+/// Whether `file_name` is `<original>-<word>.<extension>`, the name Google
+/// gives an edited copy of `<original>.<extension>`.
+fn is_edited_copy_of(file_name: &str, original: &str, extension: &str) -> bool {
+    !original.is_empty()
+        && file_name
+            .strip_prefix(original)
+            .and_then(|rest| rest.strip_prefix('-'))
+            .and_then(|rest| rest.strip_suffix(extension))
+            .and_then(|rest| rest.strip_suffix('.'))
+            .is_some_and(|word| !word.is_empty() && word.chars().all(char::is_alphabetic))
 }
 
 /// The stem plus each of its prefixes ending before a `.`, longest first — the
@@ -994,21 +1118,25 @@ mod tests {
 
     #[test]
     fn longest_prefix_wins_when_the_photo_name_itself_was_truncated() {
+        // Both sidecar names are at Google's cap, so both were cut into the
+        // photo name; the longer surviving prefix is the better claim.
+        let short = "Takeout/Google Photos/Photos from 2019/PXL_20190101_120000000.PORTRAIT_ORIGINAL_E.json";
+        let long = "Takeout/Google Photos/Photos from 2019/PXL_20190101_120000000.PORTRAIT_ORIGINAL_EXPO.json";
         let mut sidecars = HashMap::new();
         sidecar(
             &mut sidecars,
-            "Takeout/Google Photos/Photos from 2019/IMG_1.json",
+            short,
             r#"{"photoTakenTime":{"timestamp":"1"}}"#,
         );
         sidecar(
             &mut sidecars,
-            "Takeout/Google Photos/Photos from 2019/IMG_12.json",
+            long,
             r#"{"photoTakenTime":{"timestamp":"2"}}"#,
         );
         let scan = assemble(
             vec![entry(
                 0,
-                "Takeout/Google Photos/Photos from 2019/IMG_12345.jpg",
+                "Takeout/Google Photos/Photos from 2019/PXL_20190101_120000000.PORTRAIT_ORIGINAL_EXPOSURE.jpg",
                 10,
             )],
             &sidecars,
@@ -1017,6 +1145,104 @@ mod tests {
         assert_eq!(scan.photos[0].capture_time, Some(2));
     }
 
+    /// A short sidecar name was not cut, so a prefix of it names another photo:
+    /// `IMG_1.jpg`'s sidecar gave its title and date to `IMG_12.jpg`
+    /// (`docs/BUGS.md` B225).
+    #[test]
+    fn a_photo_without_a_sidecar_does_not_take_a_shorter_named_siblings() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/IMG_1.jpg.supplemental-metadata.json",
+            r#"{"title":"IMG_1.jpg","photoTakenTime":{"timestamp":"1"}}"#,
+        );
+        let scan = assemble(
+            vec![
+                entry(0, "Takeout/Google Photos/Photos from 2019/IMG_1.jpg", 10),
+                entry(0, "Takeout/Google Photos/Photos from 2019/IMG_12.jpg", 10),
+            ],
+            &sidecars,
+        );
+
+        assert_eq!(scan.photos[0].capture_time, Some(1));
+        assert_eq!(scan.photos[1].name, "IMG_12.jpg");
+        assert_eq!(scan.photos[1].capture_time, None);
+    }
+
+    /// An edited copy has no sidecar of its own. It takes its original's date,
+    /// but keeps its own name rather than the original's title.
+    #[test]
+    fn an_edited_copy_takes_its_originals_date_and_keeps_its_name() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Fotos/Urlaub/IMG_2.jpg.ergänzende-Metadaten.json",
+            r#"{"title":"Holiday.jpg","photoTakenTime":{"timestamp":"7"}}"#,
+        );
+        let scan = assemble(
+            vec![
+                entry(0, "Takeout/Google Fotos/Urlaub/IMG_2.jpg", 10),
+                entry(0, "Takeout/Google Fotos/Urlaub/IMG_2-bearbeitet.jpg", 10),
+            ],
+            &sidecars,
+        );
+
+        assert_eq!(scan.photos[0].name, "Holiday.jpg");
+        assert_eq!(scan.photos[1].name, "IMG_2-bearbeitet.jpg");
+        assert_eq!(scan.photos[1].capture_time, Some(7));
+    }
+
+    /// The index looks only at the sidecars that can match, and must find the
+    /// same one that ranking every sidecar in the folder finds.
+    #[test]
+    fn the_sidecar_index_finds_what_ranking_every_sidecar_finds() {
+        let long = "A_very_long_holiday_photo_name_from_the_beach_2019";
+        let names = [
+            "IMG_1.jpg".to_string(),
+            "IMG_12.jpg".to_string(),
+            "IMG_1(1).jpg".to_string(),
+            "IMG_1-edited.jpg".to_string(),
+            "IMG_1-bearbeitet.jpg".to_string(),
+            "my.photo(2).jpg".to_string(),
+            "x(1).jpg".to_string(),
+            "Ölbild.png".to_string(),
+            "PXL_20230101_101010.mp4".to_string(),
+            format!("{long}.jpg"),
+            format!("{long}_2.jpg"),
+            "nothing.heic".to_string(),
+        ];
+        let sidecar_names = [
+            "IMG_1.jpg.supplemental-metadata.json".to_string(),
+            "IMG_1.jpg(1).supplemental-metadata.json".to_string(),
+            "IMG_12.jpg.ergänzende-Metadaten.json".to_string(),
+            "my.photo.jpg(2).json".to_string(),
+            "x.jpg(1).json".to_string(),
+            "Ölbild.png.suppl.json".to_string(),
+            "PXL_20230101_101010.mp4.JSON".to_string(),
+            format!("{}.json", &long[..44]),
+            format!("{long}.jp.json"),
+            "IMG.json".to_string(),
+            "unrelated.json".to_string(),
+        ];
+        let bodies: Vec<Vec<u8>> = (0..sidecar_names.len())
+            .map(|i| i.to_string().into_bytes())
+            .collect();
+        let in_folder: BTreeMap<String, &Vec<u8>> =
+            sidecar_names.iter().cloned().zip(bodies.iter()).collect();
+        let index = SidecarIndex::new(&in_folder);
+        for name in &names {
+            let mut every: Option<((u8, usize), &Vec<u8>)> = None;
+            for (sidecar_name, body) in &in_folder {
+                if let Some(rank) = sidecar_rank(strip_json_suffix(sidecar_name), name)
+                    && every.as_ref().is_none_or(|(current, _)| rank < *current)
+                {
+                    every = Some((rank, *body));
+                }
+            }
+            assert_eq!(find_sidecar(name, &index), every, "{name}");
+        }
+    }
+
     #[test]
     fn sidecar_title_replaces_a_mangled_on_disk_name() {
         let mut sidecars = HashMap::new();
@@ -1106,8 +1332,8 @@ mod tests {
         ));
         let file = std::fs::File::create(&path).unwrap();
         let mut zip = zip::ZipWriter::new(file);
-        let options: zip::write::FileOptions<'_, ()> =
-            zip::write::FileOptions::default().compression_method(zip::CompressionMethod::Stored);
+        let options = zip::write::SimpleFileOptions::default()
+            .compression_method(zip::CompressionMethod::Stored);
         for (name, body) in files {
             zip.start_file(*name, options).unwrap();
             zip.write_all(body).unwrap();

crates/pdfs-core/src/timestamp.rs

@@ -0,0 +1,33 @@
+//! Convert the client's stored epoch seconds at the SDK boundary.
+
+use proton_drive_rs::ModificationTime;
+
+/// A UTC modification time, or `None` when outside the SDK's supported range.
+pub fn modification_time(seconds: i64) -> Option<ModificationTime> {
+    chrono::DateTime::from_timestamp(seconds, 0).map(|time| time.fixed_offset())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn epoch_seconds_preserve_the_instant_including_before_1970() {
+        for seconds in [-1, 0, 1_709_208_000, 1_782_482_460] {
+            let time = modification_time(seconds).unwrap();
+            assert_eq!(time.timestamp(), seconds);
+            assert_eq!(time.offset().local_minus_utc(), 0);
+            assert_eq!(time.timestamp_subsec_nanos(), 0);
+        }
+        assert_eq!(
+            modification_time(-1).unwrap().to_rfc3339(),
+            "1969-12-31T23:59:59+00:00"
+        );
+    }
+
+    #[test]
+    fn out_of_range_seconds_omit_the_timestamp() {
+        assert!(modification_time(i64::MIN).is_none());
+        assert!(modification_time(i64::MAX).is_none());
+    }
+}

crates/pdfs-core/src/update.rs

@@ -0,0 +1,178 @@
+//! The opt-in check for a newer release ([`crate::config::AppConfig::update_check`]).
+//!
+//! Only the decisions live here: what GitHub's answer says, which version is
+//! newer, when to ask again, and whether a package manager already owns
+//! updates. The desktop app does the request itself.
+
+use std::path::Path;
+use std::time::Duration;
+
+/// GitHub's latest published release. Drafts and pre-releases never show up
+/// here, so a tagged release candidate does not reach anyone.
+pub const RELEASES_LATEST_API: &str =
+    "https://api.github.com/repos/narrrl/proton-drive-linux/releases/latest";
+
+/// How often the app asks, across restarts.
+pub const CHECK_INTERVAL: Duration = Duration::from_secs(24 * 60 * 60);
+
+/// Installed next to the binaries' `share/` by packages whose package manager
+/// brings new releases (COPR, the AUR, Nix). The release `.deb`, `.rpm` and
+/// `.tar.gz` do not ship it, since nothing updates them.
+pub const MANAGED_MARKER: &str = "share/proton-drive-linux/managed-updates";
+
+/// The version of the release in a `/releases/latest` answer, without the
+/// tag's `v`. `None` for an answer that does not parse or a tag that is not
+/// `X.Y.Z`, so a changed API can never claim an update.
+pub fn latest_version(body: &[u8]) -> Option<String> {
+    let json: serde_json::Value = serde_json::from_slice(body).ok()?;
+    let tag = json.get("tag_name")?.as_str()?;
+    let version = tag.strip_prefix('v').unwrap_or(tag);
+    parse(version).map(|_| version.to_owned())
+}
+
+/// Whether `version` is a later release than `current`. Anything that is not
+/// `X.Y.Z` on either side is not.
+pub fn is_newer(version: &str, current: &str) -> bool {
+    matches!((parse(version), parse(current)), (Some(v), Some(c)) if v > c)
+}
+
+/// The release page of `version` on GitHub.
+pub fn release_url(version: &str) -> String {
+    format!("https://github.com/narrrl/proton-drive-linux/releases/tag/v{version}")
+}
+
+/// `X.Y.Z` as numbers, so `3.10.0` sorts after `3.9.0`.
+fn parse(version: &str) -> Option<(u64, u64, u64)> {
+    let mut parts = version.split('.').map(|p| p.parse::<u64>().ok());
+    let triple = (parts.next()??, parts.next()??, parts.next()??);
+    parts.next().is_none().then_some(triple)
+}
+
+/// How long until the next check is due, given the last one in Unix seconds.
+/// Zero when it is due now. A clock set back past the last check counts as
+/// due, so a wrong clock cannot stop checks.
+pub fn next_check_in(last_checked: Option<i64>, now: i64) -> Duration {
+    let interval = CHECK_INTERVAL.as_secs() as i64;
+    match last_checked {
+        Some(last) if (0..interval).contains(&(now - last)) => {
+            Duration::from_secs((interval - (now - last)) as u64)
+        }
+        _ => Duration::ZERO,
+    }
+}
+
+/// Whether the binary at `exe` was installed by a package manager that updates
+/// it, which [`MANAGED_MARKER`] next to its `bin/` says.
+pub fn updates_managed(exe: &Path) -> bool {
+    exe.parent()
+        .and_then(Path::parent)
+        .is_some_and(|prefix| prefix.join(MANAGED_MARKER).exists())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn latest(tag: &str) -> Vec<u8> {
+        format!(
+            r#"{{"tag_name":"{tag}","html_url":"https://github.com/narrrl/proton-drive-linux/releases/tag/{tag}","draft":false}}"#
+        )
+        .into_bytes()
+    }
+
+    #[test]
+    fn the_latest_release_is_read_without_its_v() {
+        assert_eq!(latest_version(&latest("v3.6.0")).as_deref(), Some("3.6.0"));
+        assert_eq!(latest_version(&latest("3.6.0")).as_deref(), Some("3.6.0"));
+    }
+
+    #[test]
+    fn an_answer_that_does_not_parse_has_no_version() {
+        assert_eq!(latest_version(b"not json"), None);
+        assert_eq!(latest_version(b"{}"), None);
+        assert_eq!(latest_version(br#"{"tag_name":7}"#), None);
+        assert_eq!(latest_version(&latest("nightly")), None);
+        assert_eq!(latest_version(&latest("v4.0.0-rc1")), None);
+        assert_eq!(latest_version(&latest("v4.0")), None);
+        assert_eq!(latest_version(&latest("v4.0.0.1")), None);
+    }
+
+    #[test]
+    fn only_a_later_release_is_newer() {
+        assert!(is_newer("3.6.0", "3.5.0"));
+        assert!(!is_newer("3.5.0", "3.5.0"));
+        assert!(!is_newer("3.4.1", "3.5.0"));
+        assert!(!is_newer("2.99.99", "3.0.0"));
+    }
+
+    #[test]
+    fn versions_compare_as_numbers() {
+        assert!(is_newer("3.10.0", "3.9.0"));
+        assert!(is_newer("3.5.10", "3.5.9"));
+        assert!(is_newer("4.0.0", "3.99.99"));
+    }
+
+    #[test]
+    fn a_version_that_is_not_x_y_z_is_never_newer() {
+        assert!(!is_newer("4.0.0", "3.5.0-dev"));
+        assert!(!is_newer("garbage", "3.5.0"));
+    }
+
+    #[test]
+    fn the_release_page_uses_the_tag() {
+        assert_eq!(
+            release_url("3.6.0"),
+            "https://github.com/narrrl/proton-drive-linux/releases/tag/v3.6.0"
+        );
+    }
+
+    #[test]
+    fn a_check_is_due_once_a_day() {
+        let day = CHECK_INTERVAL.as_secs() as i64;
+        assert_eq!(next_check_in(None, 1_000), Duration::ZERO);
+        assert_eq!(next_check_in(Some(1_000), 1_000), CHECK_INTERVAL);
+        assert_eq!(
+            next_check_in(Some(1_000), 1_000 + day - 1),
+            Duration::from_secs(1)
+        );
+        assert_eq!(next_check_in(Some(1_000), 1_000 + day), Duration::ZERO);
+        assert_eq!(
+            next_check_in(Some(1_000), 999),
+            Duration::ZERO,
+            "a clock set back must not stop checks"
+        );
+    }
+
+    /// A unique temp directory removed on drop; avoids a dev-dependency, as in
+    /// [`crate::syncignore`]'s tests.
+    struct TempDir(std::path::PathBuf);
+    impl TempDir {
+        fn new() -> Self {
+            use std::sync::atomic::{AtomicU64, Ordering};
+            static N: AtomicU64 = AtomicU64::new(0);
+            let p = std::env::temp_dir().join(format!(
+                "pdfs-update-{}-{}",
+                std::process::id(),
+                N.fetch_add(1, Ordering::Relaxed)
+            ));
+            std::fs::create_dir_all(&p).unwrap();
+            TempDir(p)
+        }
+    }
+    impl Drop for TempDir {
+        fn drop(&mut self) {
+            let _ = std::fs::remove_dir_all(&self.0);
+        }
+    }
+
+    #[test]
+    fn the_marker_next_to_bin_means_a_package_manager_updates() {
+        let prefix = TempDir::new();
+        let exe = prefix.0.join("bin/pdfs-app");
+        assert!(!updates_managed(&exe));
+        let marker = prefix.0.join(MANAGED_MARKER);
+        std::fs::create_dir_all(marker.parent().unwrap()).unwrap();
+        std::fs::write(&marker, "").unwrap();
+        assert!(updates_managed(&exe));
+    }
+}

crates/pdfs-fuse/src/attach.rs

@@ -0,0 +1,136 @@
+//! Explicitly bind an existing My files folder to a real local mirror.
+//!
+//! Unlike a FUSE mount, this never covers or evicts the local directory.
+//! The existing three-way engine performs the initial, non-destructive union.
+
+use super::{Core, parse_uid, sync};
+use pdfs_core::db::StoredSyncFolder;
+use pdfs_core::{CoreError, CoreResult};
+use proton_drive_rs::proton_sdk::ids::NodeUid;
+use std::collections::HashSet;
+use std::path::{Component, Path, PathBuf};
+
+impl Core {
+    /// A bounded, server-verified ancestry walk. Do not decide ownership or
+    /// remote-root overlap from a possibly incomplete cached folder listing.
+    pub(super) fn attach_ancestors(&self, start: &NodeUid) -> CoreResult<Vec<NodeUid>> {
+        let mut ancestors = Vec::new();
+        let mut seen = HashSet::new();
+        let mut next = Some(start.clone());
+        while let Some(uid) = next {
+            if !seen.insert(uid.clone()) || ancestors.len() >= 256 {
+                return Err(CoreError::invalid(
+                    "invalid or excessively deep remote folder ancestry",
+                ));
+            }
+            ancestors.push(uid.clone());
+            if uid == self.primary_root_uid {
+                break;
+            }
+            let nodes = self
+                .rt
+                .block_on(self.drive.enumerate_nodes(std::slice::from_ref(&uid)))
+                .map_err(|e| CoreError::from_api(&e, "verify sync folder ancestry"))?;
+            let node = nodes
+                .into_iter()
+                .next()
+                .ok_or_else(|| CoreError::not_found("remote sync folder is missing"))?;
+            if node.trashed {
+                return Err(CoreError::invalid("remote sync folder is in the trash"));
+            }
+            next = node.parent_uid;
+        }
+        Ok(ancestors)
+    }
+
+    pub(crate) fn attach_sync_folder(
+        &self,
+        local: &Path,
+        remote: &Path,
+        mountpoint: &Path,
+    ) -> CoreResult<StoredSyncFolder> {
+        let _registration = super::devices::SYNC_ROOT_REGISTRATION.lock();
+        if !self.primary {
+            return Err(CoreError::invalid("attach must use My files"));
+        }
+        if remote.is_absolute()
+            || remote
+                .components()
+                .any(|c| !matches!(c, Component::Normal(_) | Component::CurDir))
+        {
+            return Err(CoreError::invalid(
+                "remote folder must stay inside My files",
+            ));
+        }
+        let local = local
+            .canonicalize()
+            .map_err(|e| CoreError::invalid(format!("resolve {}: {e}", local.display())))?;
+        if !local.is_dir() {
+            return Err(CoreError::invalid("local sync path is not a directory"));
+        }
+        let existing = self
+            .db
+            .sync_folder_list()
+            .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
+        let others = existing
+            .iter()
+            .map(|f| PathBuf::from(&f.local_path))
+            .collect::<Vec<_>>();
+        let mut reserved = crate::devices::sync_root_reserved();
+        reserved.mountpoint = Some(
+            mountpoint
+                .canonicalize()
+                .map_err(|e| CoreError::internal(format!("resolve mountpoint: {e}")))?,
+        );
+        if let Some(problem) = pdfs_core::syncroot::problem(&local, &others, &reserved) {
+            return Err(CoreError::invalid(problem));
+        }
+        let (ino, remote_uid) = self.resolve(remote)?;
+        let is_folder = self
+            .state()
+            .entries
+            .get(&ino)
+            .is_some_and(|e| e.node.is_folder() && !e.node.trashed);
+        if !is_folder {
+            return Err(CoreError::invalid("remote sync path is not a folder"));
+        }
+        let ancestors = self.attach_ancestors(&remote_uid)?;
+        if remote_uid == self.primary_root_uid || !ancestors.contains(&self.primary_root_uid) {
+            return Err(CoreError::invalid(
+                "choose an owned folder below My files, not its root or a shared folder",
+            ));
+        }
+        for other in existing.iter().filter(|f| f.kind == "attached") {
+            let uid = parse_uid(&other.remote_uid)
+                .ok_or_else(|| CoreError::internal("invalid existing remote sync root"))?;
+            if uid == remote_uid
+                || ancestors.contains(&uid)
+                || self.attach_ancestors(&uid)?.contains(&remote_uid)
+            {
+                return Err(CoreError::invalid(
+                    "remote folder overlaps an existing synced folder",
+                ));
+            }
+        }
+        let share_id = self
+            .rt
+            .block_on(self.drive.context_share_id(&self.primary_root_uid))
+            .map_err(|e| CoreError::from_api(&e, "resolve My files share"))?
+            .to_string();
+        if share_id.is_empty() {
+            return Err(CoreError::invalid("My files share is unavailable"));
+        }
+        let id = self
+            .db
+            .sync_folder_attach(&local.to_string_lossy(), &remote_uid.to_string(), &share_id)
+            .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
+        // An empty baseline makes one-sided files new, never deletions. The
+        // engine hashes matching-size files and preserves divergent versions.
+        let _ = self.sync_tx.send(sync::SyncMsg::Rewatch);
+        let _ = self.sync_tx.send(sync::SyncMsg::Reconcile(id));
+        self.db
+            .sync_folder_get(id)
+            .map_err(|e| CoreError::internal(format!("db: {e:?}")))?
+            .ok_or_else(|| CoreError::not_found("new sync folder disappeared"))
+    }
+}

crates/pdfs-fuse/src/background.rs

@@ -157,6 +157,17 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
             if ours {
                 debug!(uid = %node_uid, "ignoring remote event for a node with a queued write");
             }
+            // A file kept offline keeps its copy through a change, and the
+            // keeper replaces it once this batch's listings are read again.
+            // The copy is checked against the revision's `(mtime, size)`, so
+            // no read takes it for a newer revision. Evicted, it was gone until
+            // something read the file, which then downloaded it (B282). A
+            // node new in, or moved into, a kept folder is fetched by checking
+            // that folder.
+            let kept = match !*is_trashed && !ours {
+                true => kept_by_pin(core, node_uid, parent_node_uid.as_ref()),
+                false => None,
+            };
             let mut had_node = false;
             core.for_each_mount(|st, notify| {
                 if *is_trashed {
@@ -172,9 +183,12 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
                 }
             });
             // Once, not once per mount: the content cache is per-daemon.
-            if had_node {
+            if had_node && kept.is_none() {
                 core.cache.evict(node_uid);
             }
+            if let Some(kept) = kept {
+                dirty.kept.insert(kept);
+            }
             // A create, rename or move-in shows up as a change to the parent
             // listing too, which is recorded for the end of the batch rather
             // than acted on here — see [`DirtyParents`].
@@ -205,6 +219,8 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
         | DriveEvent::ScopeAccessLost { .. }
         | DriveEvent::SharedWithMeUpdated { .. } => {
             warn!("event access continuity lost; downgrading shared trees and resyncing lazily");
+            // Changes went by unseen, kept files among them (B282).
+            core.recheck_all_pins();
             apply_result = apply_result.and(core.db.clear_state(SHARED_WITH_ME_SYNCED_MS));
             core.for_each_mount(|st, notify| {
                 let dirs: Vec<u64> = st.children.keys().copied().collect();
@@ -296,6 +312,21 @@ struct DirtyParents {
     /// Checked per mount — a mount that already lists every one of those
     /// children under that parent keeps its listing.
     ours: HashMap<NodeUid, HashSet<NodeUid>>,
+    /// Pinned files and folders the batch changed, for the pin keeper to
+    /// check once the listings above are dropped (`keeper`).
+    kept: HashSet<NodeUid>,
+}
+
+/// What the pin keeper has to check after a remote change to `node_uid`,
+/// whose parent is now `parent_uid`: the node itself when a pin keeps it, or
+/// else the parent, when a pinned folder holds it and the node is new there.
+fn kept_by_pin(core: &Core, node_uid: &NodeUid, parent_uid: Option<&NodeUid>) -> Option<NodeUid> {
+    if core.cache.is_pinned(node_uid) {
+        return Some(node_uid.clone());
+    }
+    parent_uid
+        .filter(|parent| core.cache.is_pinned(parent))
+        .cloned()
 }
 
 /// Whether this mount's cached listing of `parent_uid` already accounts for
@@ -476,6 +507,9 @@ pub(super) async fn run_event_sync(
             cursor = Some(applied);
         }
         flush_dirty_parents(&core, &dirty);
+        for uid in &dirty.kept {
+            core.recheck_pinned(uid);
+        }
         // Another device changed the tree: whatever a front-end lists may have
         // moved, including what is shared and what is in the trash.
         core.events
@@ -723,16 +757,24 @@ fn scan_local_once(
     // has seen and stays indeterminate.
     let job = transfers.begin_background_job("Indexing this computer");
     job.detail("Scanning your files");
+    let mut failed = false;
     let walked = localindex::scan(&[home], &excludes, |batch| {
         if let Err(e) = db.local_upsert_batch(generation, &batch) {
             warn!(error = %e, "local index: batch write failed");
+            failed = true;
         }
     });
 
-    // Prune what this scan did not see and rebuild the FTS index over the rest,
-    // even if some batches failed — a partial index still beats none.
+    // Prune what this scan did not see, unless it did not see everything:
+    // a path it never reached, or one whose batch failed to write, is not a
+    // path that is gone (`docs/BUGS.md` B217).
     job.detail("Building the search index");
-    match db.local_finish_scan(generation, now_secs()) {
+    let finished = if failed || walked >= localindex::MAX_ENTRIES {
+        db.local_finish_partial_scan(now_secs())
+    } else {
+        db.local_finish_scan(generation, now_secs())
+    };
+    match finished {
         Ok(indexed) => info!(
             walked,
             indexed,

crates/pdfs-fuse/src/control.rs

@@ -29,6 +29,17 @@ use super::{Core, count_noun, human_bytes, human_duration, parse_uid};
 
 const MAX_CONTROL_REQUEST_BYTES: u64 = 1024 * 1024;
 const CONTROL_READ_TIMEOUT: Duration = Duration::from_secs(10);
+/// Answer a [`CtlRequest::FolderSize`].
+fn folder_size_reply(size: CoreResult<proton_drive_rs::FolderSize>) -> CtlResponse {
+    match size {
+        Ok(size) => CtlResponse::FolderSize {
+            size: size.size,
+            items: size.descendants,
+        },
+        Err(e) => CtlResponse::error(e),
+    }
+}
+
 /// Answer a [`CtlRequest::StopSharing`]: log it, and turn a partial removal
 /// into an error that names what is still shared.
 fn stop_sharing_reply(
@@ -99,7 +110,7 @@ struct ControlHandlerPermit;
 impl ControlHandlerPermit {
     fn acquire() -> Option<Self> {
         ACTIVE_CONTROL_HANDLERS
-            .fetch_update(Ordering::AcqRel, Ordering::Acquire, |active| {
+            .try_update(Ordering::AcqRel, Ordering::Acquire, |active| {
                 (active < MAX_CONTROL_HANDLERS).then_some(active + 1)
             })
             .ok()
@@ -193,18 +204,42 @@ fn route_to_mount(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Cor
 /// B99), so resolving one needs this too. A mirror folder has no mount to run
 /// against: a file there is an ordinary local file.
 fn route_change(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core, PathBuf)> {
+    route_within(core, mountpoint, path, |path| {
+        format!("{path} is in a mirrored folder; change the local file there instead")
+    })
+}
+
+/// [`route_to_mount`] for keeping a node offline or releasing it. A file in an
+/// on-demand synced folder is a different Drive node from any file of the
+/// same name under the primary mount, and keeping one offline did nothing for
+/// the other: a program reading the synced folder's copy downloaded it
+/// (`docs/BUGS.md` B281). A mirror folder already holds every file on disk.
+fn route_keep(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core, PathBuf)> {
+    route_within(core, mountpoint, path, |path| {
+        format!(
+            "{path} is in a mirrored folder, which keeps all its files on this computer already"
+        )
+    })
+}
+
+/// [`route_to_mount`], refusing a path that leaves the mount it routed to and
+/// answering a path in a mirror folder, which has no mount, with `mirrored`.
+fn route_within(
+    core: &Core,
+    mountpoint: &Path,
+    path: &str,
+    mirrored: impl FnOnce(&str) -> String,
+) -> CoreResult<(Core, PathBuf)> {
     let routed = route_to_mount(core, mountpoint, path).map_err(|e| {
         let p = Path::new(path);
-        let mirrored = core
+        let in_mirror = core
             .db
             .sync_folder_list()
             .unwrap_or_default()
             .iter()
             .any(|folder| folder.mode == "mirror" && p.starts_with(&folder.local_path));
-        if mirrored {
-            CoreError::invalid(format!(
-                "{path} is in a mirrored folder; change the local file there instead"
-            ))
+        if in_mirror {
+            CoreError::invalid(mirrored(path))
         } else {
             e
         }
@@ -220,6 +255,18 @@ fn route_change(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core,
     }
 }
 
+/// The path the pin registry keeps for a pin made through `routed`: the
+/// mount-relative path on the primary mount, as it always was, and the
+/// absolute path the request named on an on-demand folder's mount, since
+/// that node is not under the primary mountpoint (`docs/BUGS.md` B281).
+fn pin_record(routed: &Core, rel: &Path, path: &str) -> PathBuf {
+    if routed.primary {
+        rel.to_path_buf()
+    } else {
+        Path::new(path).components().collect()
+    }
+}
+
 /// [`route_change`] for a request that trashes or renames the node it names.
 /// A mount's root is My files or a whole synced folder. An on-demand folder's
 /// root has a parent on Drive, so nothing further down would stop `pdfs rm
@@ -336,6 +383,7 @@ pub(crate) fn status_response(core: &Core, username: &str, mountpoint: &Path) ->
         online: core.online.load(Ordering::Relaxed),
         session_expired: core.session_expired(),
         tokens_unsaved: pdfs_core::auth::tokens_unsaved(),
+        version: env!("CARGO_PKG_VERSION").to_string(),
         pending_uploads: queued.uploads.max(0) as u64 + landing,
         pending_changes: queued.changes.max(0) as u64,
     }
@@ -373,9 +421,11 @@ fn touched_topics(request: &CtlRequest) -> &'static [Topic] {
         R::RenameDevice { .. } | R::DeleteDevice { .. } => &[Topic::Devices],
         R::AdoptDevice { .. } | R::MigrateDevice { .. } => &[Topic::Devices, Topic::Locations],
         R::AddSyncFolder { .. }
+        | R::AttachSyncFolder { .. }
         | R::RemoveSyncFolder { .. }
         | R::SetSyncFolderMode { .. }
         | R::SetSyncFolderPaused { .. }
+        | R::ResetSyncFolder { .. }
         | R::RestoreSyncFolders { .. }
         | R::RestoreDeviceFolders { .. } => &[Topic::Locations, Topic::Devices],
         R::RetryPendingOp { .. } => &[Topic::Queue],
@@ -391,6 +441,8 @@ fn touched_topics(request: &CtlRequest) -> &'static [Topic] {
         | R::CreatePublicLinkByUid { .. }
         | R::RemovePublicLink { .. }
         | R::RemovePublicLinkByUid { .. }
+        | R::UpdatePublicLink { .. }
+        | R::UpdatePublicLinkByUid { .. }
         | R::StopSharing { .. }
         | R::StopSharingByUid { .. } => &[Topic::Shares, Topic::Files],
         R::LeaveShared { .. }
@@ -505,8 +557,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
         Ok(CtlRequest::Subscribe) => {
             CtlResponse::error(CoreError::invalid("a subscription is served on its own"))
         }
-        Ok(CtlRequest::Pin { path }) => match rel_to_mount(mountpoint, &path) {
-            Ok(rel) => match core.pin(&rel) {
+        Ok(CtlRequest::Pin { path }) => match route_keep(core, mountpoint, &path) {
+            Ok((routed, rel)) => match routed.pin(&rel, &pin_record(&routed, &rel, &path)) {
                 Ok(name) => {
                     core.touch_profile();
                     CtlResponse::Ok {
@@ -517,8 +569,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             },
             Err(e) => CtlResponse::error(e),
         },
-        Ok(CtlRequest::Unpin { path }) => match rel_to_mount(mountpoint, &path) {
-            Ok(rel) => match core.unpin(&rel) {
+        Ok(CtlRequest::Unpin { path }) => match route_keep(core, mountpoint, &path) {
+            Ok((routed, rel)) => match routed.unpin(&rel) {
                 Ok(name) => {
                     core.touch_profile();
                     CtlResponse::Ok {
@@ -910,10 +962,24 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 ))),
                 Ok((file, len)) => {
                     let photos = core.photos();
+                    // Unless the caller knows better: the photo's own EXIF,
+                    // then the file's modification time, which a copy resets.
+                    let capture_time = capture_time.or_else(|| {
+                        let path = Path::new(&source_path);
+                        pdfs_core::exiftime::capture_time_of(path).or_else(|| {
+                            let modified =
+                                std::fs::metadata(path).and_then(|m| m.modified()).ok()?;
+                            let since = modified.duration_since(std::time::UNIX_EPOCH).ok()?;
+                            Some(since.as_secs() as i64)
+                        })
+                    });
                     let metadata = proton_drive_rs::PhotoUploadMetadata {
                         capture_time,
+                        last_modification_time: capture_time
+                            .and_then(pdfs_core::timestamp::modification_time),
                         ..Default::default()
                     };
+                    let thumbnails = core.upload_thumbnails(Path::new(&source_path), &name);
                     let guard =
                         core.transfers
                             .begin(name.clone(), "", TransferDirection::Upload, len);
@@ -923,7 +989,7 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                         &media_type,
                         reader,
                         len as i64,
-                        Vec::new(),
+                        thumbnails,
                         metadata,
                         false,
                     )) {
@@ -940,6 +1006,9 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                             }
                         }
                         Err(e) => {
+                            // The reply goes to the app's toast only; without
+                            // this the journal shows a failure and no reason.
+                            warn!(error = %e, "photo upload failed");
                             CtlResponse::error(CoreError::from_api(&e, "upload photo failed"))
                         }
                     }
@@ -1047,6 +1116,36 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 (Err(e), _) | (_, Err(e)) => CtlResponse::error(e),
             }
         }
+        Ok(CtlRequest::Copy { path, new_parent }) => {
+            match (
+                rel_to_mount(mountpoint, &path),
+                rel_to_mount(mountpoint, &new_parent),
+            ) {
+                (Ok(rel), Ok(parent_rel)) => match core.copy_to(&rel, &parent_rel) {
+                    Ok(name) => {
+                        let dest = if new_parent.is_empty() {
+                            "My files".to_string()
+                        } else {
+                            new_parent.clone()
+                        };
+                        core.log_activity(ActivityKind::Copy, &name, format!("to {dest}"), true);
+                        CtlResponse::Ok {
+                            message: format!("copied to {name}"),
+                        }
+                    }
+                    Err(e) => {
+                        core.log_activity(ActivityKind::Copy, &path, &e, false);
+                        CtlResponse::error(e)
+                    }
+                },
+                (Err(e), _) | (_, Err(e)) => CtlResponse::error(e),
+            }
+        }
+        Ok(CtlRequest::FolderSize { path }) => match rel_to_mount(mountpoint, &path) {
+            Ok(rel) => folder_size_reply(core.folder_size(&rel)),
+            Err(e) => CtlResponse::error(e),
+        },
+        Ok(CtlRequest::FolderSizeByUid { uid }) => folder_size_reply(core.folder_size_by_uid(&uid)),
         Ok(CtlRequest::Delete { path }) => match route_node(core, mountpoint, &path) {
             Ok((core, rel)) => match core.delete(&rel) {
                 Ok(name) => {
@@ -1337,6 +1436,20 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 message: format!("adding {local_path}"),
             }
         }
+        Ok(CtlRequest::AttachSyncFolder {
+            local_path,
+            remote_path,
+        }) => {
+            let result = rel_to_mount(mountpoint, &remote_path).and_then(|remote| {
+                core.attach_sync_folder(Path::new(&local_path), &remote, mountpoint)
+            });
+            match result {
+                Ok(folder) => CtlResponse::Ok {
+                    message: format!("sync folder {} attached: {}", folder.id, folder.local_path),
+                },
+                Err(error) => CtlResponse::error(error),
+            }
+        }
         Ok(CtlRequest::ListSyncFolders) => match core.list_sync_folders() {
             Ok(items) => CtlResponse::SyncFolders { items },
             Err(e) => CtlResponse::error(e),
@@ -1373,6 +1486,13 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 Err(e) => CtlResponse::error(e),
             }
         }
+        Ok(CtlRequest::ResetSyncFolder { id }) => match core.reset_sync_folder(id) {
+            Ok(message) => {
+                core.log_activity(ActivityKind::Sync, &message, "", true);
+                CtlResponse::Ok { message }
+            }
+            Err(e) => CtlResponse::error(e),
+        },
         Ok(CtlRequest::SyncNow { id }) => {
             core.sync_now(id);
             CtlResponse::Ok {
@@ -1459,9 +1579,17 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             let core = core.clone();
             std::thread::spawn(move || {
                 match core.restore_sync_folders(&items, device.as_deref()) {
-                    Ok(message) => {
+                    Ok(outcome) => {
                         core.touch_profile();
-                        core.log_activity(ActivityKind::Download, &message, "", true);
+                        if !outcome.complete() {
+                            warn!(skipped = ?outcome.skipped, "restore skipped folders");
+                        }
+                        core.log_activity(
+                            ActivityKind::Download,
+                            outcome.summary(),
+                            outcome.skipped.join("; "),
+                            outcome.complete(),
+                        );
                     }
                     Err(e) => {
                         warn!(error = %e, "restore failed");
@@ -1614,6 +1742,31 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 CtlResponse::error(e)
             }
         },
+        Ok(CtlRequest::UpdatePublicLink {
+            path,
+            id,
+            role,
+            password,
+            expires,
+        }) => match rel_to_mount(mountpoint, &path) {
+            Ok(rel) => {
+                match core.update_public_link(&rel, &id, role.as_deref(), password, expires) {
+                    Ok(link) => CtlResponse::PublicLink { link },
+                    Err(e) => CtlResponse::error(e),
+                }
+            }
+            Err(e) => CtlResponse::error(e),
+        },
+        Ok(CtlRequest::UpdatePublicLinkByUid {
+            uid,
+            id,
+            role,
+            password,
+            expires,
+        }) => match core.update_public_link_by_uid(&uid, &id, role.as_deref(), password, expires) {
+            Ok(link) => CtlResponse::PublicLink { link },
+            Err(e) => CtlResponse::error(e),
+        },
         Ok(CtlRequest::RemovePublicLink { path, id }) => match rel_to_mount(mountpoint, &path) {
             Ok(rel) => match core.remove_public_link(&rel, &id) {
                 Ok(()) => {

crates/pdfs-fuse/src/devices.rs

@@ -33,6 +33,11 @@ use super::{
     now_secs, parse_uid, spawn_session, sync_folder_info, this_hostname,
 };
 
+/// Registration validates local and remote root overlap before inserting a
+/// mapping. Serialize all registration paths so concurrent control requests
+/// cannot both validate against the same old set of roots.
+pub(super) static SYNC_ROOT_REGISTRATION: Mutex<()> = Mutex::new(());
+
 /// A mode that this daemon is allowed to apply.
 ///
 /// Persisted and control-protocol values first pass through [`MountMode`] so
@@ -105,6 +110,15 @@ pub(crate) fn adopted_device_uid() -> Option<String> {
     (!uid.is_empty()).then_some(uid)
 }
 
+/// The paths no sync root may overlap, with the mountpoint as the config says
+/// now.
+pub(crate) fn sync_root_reserved() -> pdfs_core::syncroot::Reserved {
+    let config = pdfs_core::config::AppDirs::new()
+        .map(|dirs| dirs.load_config())
+        .unwrap_or_default();
+    pdfs_core::syncroot::Reserved::current(&config)
+}
+
 /// Pin (or, with `None`, unpin) the adopted device uid in `config.json`.
 pub(crate) fn set_adopted_device_uid(uid: Option<&str>) -> CoreResult<()> {
     let dirs = pdfs_core::config::AppDirs::new()
@@ -143,7 +157,9 @@ impl Core {
             .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
         for location in &mut locations {
             location.mounted = self.states.is_mounted_at(Path::new(&location.local_path));
-            if let MountKind::Device { sync_folder_id } = &location.kind {
+            if let MountKind::Device { sync_folder_id } | MountKind::Attached { sync_folder_id } =
+                &location.kind
+            {
                 location.progress = progress.get(sync_folder_id).cloned();
                 location.paused = self.sync_folder_paused(*sync_folder_id);
             }
@@ -157,7 +173,7 @@ impl Core {
     pub(crate) fn list_devices(&self) -> CoreResult<Vec<DeviceInfo>> {
         let devices = self
             .rt
-            .block_on(self.client.enumerate_devices())
+            .block_on(self.drive.enumerate_devices())
             .map_err(|e| CoreError::from_api(&e, "list devices"))?;
         // No cached device row yet means this machine syncs nothing, so none of
         // the listed devices is ours.
@@ -214,7 +230,7 @@ impl Core {
         };
         let remote = self
             .rt
-            .block_on(self.client.enumerate_devices())
+            .block_on(self.drive.enumerate_devices())
             .map_err(|e| CoreError::from_api(&e, "enumerate devices"))?;
         let dev = remote
             .into_iter()
@@ -257,7 +273,7 @@ impl Core {
         };
         let remote = self
             .rt
-            .block_on(self.client.enumerate_devices())
+            .block_on(self.drive.enumerate_devices())
             .map_err(|e| CoreError::from_api(&e, "enumerate devices"))?;
         let d = remote
             .into_iter()
@@ -395,7 +411,7 @@ impl Core {
         // any cached record, and recover an existing device by name.
         let remote = self
             .rt
-            .block_on(self.client.enumerate_devices())
+            .block_on(self.drive.enumerate_devices())
             .map_err(|e| CoreError::from_api(&e, "enumerate devices"))?;
 
         // An adopted uid is an explicit instruction, so it outranks everything
@@ -454,7 +470,7 @@ impl Core {
             None => {
                 let d = self
                     .rt
-                    .block_on(self.client.create_device(&name, DeviceType::Linux))
+                    .block_on(self.drive.create_device(&name, DeviceType::Linux))
                     .map_err(|e| CoreError::from_api(&e, "create device"))?;
                 StoredDevice {
                     uid: d.uid.to_string(),
@@ -486,7 +502,7 @@ impl Core {
     }
 
     /// Everything directly under a device root, trashed nodes included.
-    fn device_root_nodes(&self, root_uid: &NodeUid) -> CoreResult<Vec<Node>> {
+    pub(super) fn device_root_nodes(&self, root_uid: &NodeUid) -> CoreResult<Vec<Node>> {
         let uids = self
             .rt
             .block_on(self.drive.enumerate_folder_children_node_uids(root_uid))
@@ -504,6 +520,7 @@ impl Core {
     /// tree into it once, and record the mapping. Phase 1 is a one-shot upload —
     /// the two-way engine (Phase 2) reconciles later changes.
     pub(crate) fn add_sync_folder(&self, local: &Path) -> CoreResult<StoredSyncFolder> {
+        let _registration = SYNC_ROOT_REGISTRATION.lock();
         let meta = std::fs::metadata(local)
             .map_err(|e| CoreError::internal(format!("stat {}: {e}", local.display())))?;
         if !meta.is_dir() {
@@ -517,18 +534,20 @@ impl Core {
             .map_err(|e| CoreError::internal(format!("canonicalize {}: {e}", local.display())))?;
         let local_str = local.to_string_lossy().to_string();
 
-        // Reject duplicates up front for a clear error (UNIQUE would also catch it).
-        if self
+        // `/`, the home folder, the mount, this app's own data, and a folder
+        // inside or around another root are refused (`syncroot::problem`). A
+        // duplicate is one of those, refused here for a clear error before
+        // the UNIQUE constraint would catch it.
+        let others = self
             .db
             .sync_folder_list()
             .map_err(|e| CoreError::internal(format!("db: {e:?}")))?
             .iter()
-            .any(|f| f.local_path == local_str)
-        {
-            return Err(CoreError::invalid(format!(
-                "{} is already synced",
-                local.display()
-            )));
+            .map(|f| PathBuf::from(&f.local_path))
+            .collect::<Vec<_>>();
+        let reserved = sync_root_reserved();
+        if let Some(problem) = pdfs_core::syncroot::problem(&local, &others, &reserved) {
+            return Err(CoreError::invalid(problem));
         }
 
         let name = local
@@ -688,6 +707,11 @@ impl Core {
             .sync_folder_get(id)
             .map_err(|e| CoreError::internal(format!("db: {e:?}")))?
             .ok_or_else(|| CoreError::not_found(format!("no synced folder with id {id}")))?;
+        if folder.kind == "attached" && delete_remote {
+            return Err(CoreError::invalid(
+                "attached My files folders cannot be deleted by stopping sync; omit --delete-remote",
+            ));
+        }
         // An `ondemand` folder *is* a FUSE mount over its local path, so dropping
         // only the row would strand the mount: the path would keep serving a
         // folder the daemon no longer tracks, and nothing would ever unmount it.
@@ -774,6 +798,11 @@ impl Core {
             .sync_folder_get(id)
             .map_err(|e| CoreError::internal(format!("db: {e:?}")))?
             .ok_or_else(|| CoreError::not_found(format!("no synced folder with id {id}")))?;
+        if folder.kind == "attached" && target_mode != ApplicableMountMode::Mirror {
+            return Err(CoreError::invalid(
+                "attached My files folders only support mirror mode; use the My files mount for online-only access",
+            ));
+        }
         let current_mode = ApplicableMountMode::parse(&folder.mode)
             .map_err(|error| CoreError::invalid(format!("unsupported current mode: {error}")))?;
         // A switch waits on the folder's reconcile, which a pause skips; refuse
@@ -949,6 +978,11 @@ impl Core {
             .sync_folder_get(id)
             .map_err(|e| SwitchBlocked::Failed(format!("db: {e:?}")))?
             .ok_or_else(|| SwitchBlocked::Failed(format!("no synced folder with id {id}")))?;
+        if folder.kind == "attached" && mode != ApplicableMountMode::Mirror {
+            return Err(SwitchBlocked::Failed(
+                "attached My files folders only support mirror mode".into(),
+            ));
+        }
         if !pending_intent_matches(folder.pending_mode.as_deref(), expected_pending) {
             return Err(SwitchBlocked::Superseded);
         }
@@ -978,9 +1012,15 @@ impl Core {
                     .db
                     .sync_entries(id)
                     .map_err(|e| SwitchBlocked::Failed(format!("db: {e:?}")))?;
-                if let Some(reason) =
-                    sync::mirror_tree_unsynced(&local, &baseline, &self.ignore_rules(&local))
-                {
+                let rules = self.ignore_rules(&local);
+                // Emptied before any pass saw it, the folder is still `idle`, and
+                // the check below would refuse the switch for good. The push pass
+                // of a queued switch forgets those paths instead (`docs/BUGS.md`
+                // B255).
+                if sync::mirror_tree_gone(&local, &baseline, &rules) {
+                    return Err(SwitchBlocked::NotNow);
+                }
+                if let Some(reason) = sync::mirror_tree_unsynced(&local, &baseline, &rules) {
                     return Err(SwitchBlocked::Failed(format!(
                         "going online-only would delete what is only on this computer: {reason}"
                     )));
@@ -1069,6 +1109,50 @@ impl Core {
         }
     }
 
+    /// Forget what a mirror folder synced before, so its next pass compares the
+    /// two sides as on the first sync: what one side has alone is copied to the
+    /// other, and a file that differs is kept twice as a conflict. Nothing is
+    /// deleted on either side.
+    ///
+    /// This is the way out for a folder whose passes refuse to run because its
+    /// whole local copy, or its whole copy on Drive, is gone (#46). The baseline
+    /// is what makes that read as "delete everything", and it is what this
+    /// drops. A queued switch to on-demand is dropped with it: the push pass
+    /// that switch runs reads an unrecorded local file as new and would upload
+    /// a second copy of every file Drive already has.
+    pub(crate) fn reset_sync_folder(&self, id: i64) -> CoreResult<String> {
+        let lock = self.sync_lock(id);
+        let Some(_guard) = lock.try_lock() else {
+            return Err(CoreError::conflict(
+                "this folder is syncing; try again when the pass ends",
+            ));
+        };
+        let folder = self
+            .db
+            .sync_folder_get(id)
+            .map_err(|e| CoreError::internal(format!("db: {e:?}")))?
+            .ok_or_else(|| CoreError::not_found(format!("no synced folder with id {id}")))?;
+        if folder.mode != "mirror" {
+            return Err(CoreError::invalid(
+                "an online-only folder keeps nothing on this computer to sync from scratch",
+            ));
+        }
+        self.db
+            .sync_entries_clear(id)
+            .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
+        if folder.pending_mode.as_deref() == Some("ondemand") {
+            self.db
+                .sync_folder_set_pending_mode(id, None)
+                .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
+        }
+        let _ = self.sync_tx.send(sync::SyncMsg::Reconcile(id));
+        info!(id, path = %folder.local_path, "sync folder reset");
+        Ok(format!(
+            "{} will sync from scratch",
+            base_name(&folder.local_path)
+        ))
+    }
+
     /// Spawn a secondary FUSE session rooted at `root` over `local` from a
     /// [`Core::fork_state`] sibling. Clears any stale kernel mount first (a crashed run can leave
     /// one, which would fail the fresh mount with EBUSY).
@@ -1138,7 +1222,7 @@ impl Core {
             }
         };
         for folder in folders {
-            if folder.mode != "ondemand" {
+            if folder.kind != "device" || folder.mode != "ondemand" {
                 continue;
             }
             let Some(root_uid) = parse_uid(&folder.remote_uid) else {
@@ -1334,6 +1418,7 @@ mod tests {
 
     fn folder(local_path: &str, remote_uid: &str, mode: &str) -> StoredSyncFolder {
         StoredSyncFolder {
+            kind: "device".into(),
             id: 7,
             local_path: local_path.to_string(),
             remote_uid: remote_uid.to_string(),

crates/pdfs-fuse/src/diagnostics.rs

@@ -163,6 +163,7 @@ impl Core {
             control_handlers: super::control::active_handlers(),
             control_handler_limit: super::control::handler_limit(),
             pending_ops: self.pending_ops_quickly(),
+            sync: Some(self.sync_engine.report()),
         }
     }
 

crates/pdfs-fuse/src/drain.rs

@@ -389,13 +389,7 @@ impl Core {
                 // A name a change of ours is about to free is a wait, not a
                 // failure: the trash or rename holding it lands in moments.
                 let held = waits_for_name(e.as_ref());
-                let backoff = if held {
-                    DRAIN_BACKOFF_MIN
-                } else {
-                    DRAIN_BACKOFF_MIN
-                        .saturating_mul(1u32 << attempts.min(6))
-                        .min(DRAIN_BACKOFF_MAX)
-                };
+                let backoff = drain_backoff(attempts, held, op.id);
                 warn!(uid = %op.uid, attempts, error = %err_str, "pending upload failed; will retry");
                 if let Err(e) = self.db.record_attempt_failure(
                     op.id,
@@ -1118,7 +1112,7 @@ impl Core {
             _ => None,
         };
         let sent = self.create_sent_digests(op.id, current);
-        Ok(adoptable(is_dir, &twin, op.created_at, &sent).then_some(twin.uid))
+        Ok(adoptable(is_dir, &twin, self.first_sent(op), &sent).then_some(twin.uid))
     }
 
     /// Record the name the remote actually gave a node, after a conflict forced
@@ -1287,6 +1281,13 @@ impl Core {
             sent: (&sent.0, &sent.1),
             landed: (&home.to_string(), &name),
         };
+        // Counted from the op's retirement until the bytes are cached and the
+        // tree has the real uid, as an upload is. Uncounted, the queue read
+        // empty while that still ran: a delete in between took an open file
+        // for closed and dropped what its handle reads, and a script that
+        // waited for an empty queue read the file before it was cached
+        // (`docs/BUGS.md` B257).
+        let _landing = LandingUpload::begin(&self.landing_uploads);
         let newer = match self.retire_create(op, uploaded, &landing, &local, &real)? {
             CreateRetired::Withdrawn { trash } => {
                 return self.trash_withdrawn_create(op, trash, &local, &real, &name);
@@ -1513,8 +1514,10 @@ impl Core {
             .as_deref()
             .is_some_and(|sha| holds_bytes(&twin, sha));
         let sent = self.create_sent_digests(op.id, current);
-        Ok(adoptable(op.kind == OP_MKDIR, &twin, op.created_at, &sent)
-            .then_some((twin.uid, holds_blob)))
+        Ok(
+            adoptable(op.kind == OP_MKDIR, &twin, self.first_sent(op), &sent)
+                .then_some((twin.uid, holds_blob)),
+        )
     }
 
     /// The SHA-1s of the bytes queued create `id` may have made its file with:
@@ -1529,6 +1532,22 @@ impl Core {
         sent
     }
 
+    /// When create `op` first went out, which is the earliest a node its lost
+    /// answer left can have been made. An op queued offline may wait for days
+    /// before that; measured from when it was queued, the adoption window let
+    /// it take a node another device made in the meantime. Ops sent before the
+    /// time was recorded fall back to when they were queued.
+    fn first_sent(&self, op: &PendingOp) -> i64 {
+        match self.db.create_first_sent(op.id) {
+            Ok(Some(at)) => at.max(op.created_at),
+            Ok(None) => op.created_at,
+            Err(e) => {
+                warn!(id = op.id, error = %e, "reading when a queued create was sent failed");
+                op.created_at
+            }
+        }
+    }
+
     /// Make one queued `create`/`mkdir` real under a given name, and hand back
     /// the API's own error so the caller can tell a name clash from a failure.
     ///
@@ -1541,7 +1560,7 @@ impl Core {
         name: &str,
     ) -> Result<NodeUid, Box<dyn std::error::Error>> {
         self.db
-            .note_create_target(op.id, &parent.to_string(), name)?;
+            .note_create_target(op.id, &parent.to_string(), name, now_millis())?;
         match op.kind == OP_MKDIR {
             true => Ok(self.block_on_bounded(self.drive.create_folder(
                 parent,
@@ -1586,7 +1605,7 @@ impl Core {
             .begin(name, op.uid.clone(), TransferDirection::Upload, meta.len);
         let reader = CountingReader::new(File::open(blob)?, &guard);
         let uid = self.block_on_within(
-            link::upload_deadline(meta.len),
+            link::upload_deadline(meta.len, self.transfers.upload_cap()),
             self.drive.upload_file_from(
                 parent,
                 name,
@@ -1983,7 +2002,7 @@ impl Core {
                 .begin(&alt, meta.uid.clone(), TransferDirection::Upload, meta.len);
         let reader = CountingReader::new(File::open(blob)?, &guard);
         self.block_on_within(
-            link::upload_deadline(meta.len),
+            link::upload_deadline(meta.len, self.transfers.upload_cap()),
             self.drive.upload_file_from(
                 &parent,
                 &alt,
@@ -2236,7 +2255,7 @@ impl Core {
             .clone()
             .ok_or("pending op has no staged blob")?;
         let blob = PathBuf::from(blob);
-        let meta: StagedWrite = serde_json::from_str(op.meta_json.as_deref().unwrap_or(""))?;
+        let mut meta: StagedWrite = serde_json::from_str(op.meta_json.as_deref().unwrap_or(""))?;
         let uid = parse_node_uid(&meta.uid).ok_or("staged write has an unparseable uid")?;
 
         if let Some(reason) = self.revision_conflict(&uid, &meta, &blob)? {
@@ -2275,6 +2294,22 @@ impl Core {
                 &written,
             )
             .map_err(|e| self.errno_error(e, "gap-fill from base failed"))?;
+            // The blob is whole now. Recorded, so that a retry after a lost
+            // answer can match these bytes against the server's revision
+            // (`revision_conflict`) instead of forking a conflict copy of the
+            // user's own write.
+            meta.complete = true;
+            match serde_json::to_string(&meta) {
+                Ok(json) => {
+                    let path = op.blob_path.as_deref().unwrap_or_default();
+                    if let Err(e) = self.db.update_op_meta_for_blob(op.id, path, &json) {
+                        warn!(%uid, error = %e,
+                              "recording a gap-filled blob as whole failed; \
+                               a lost answer may land it as a conflict copy");
+                    }
+                }
+                Err(e) => warn!(%uid, error = %e, "serializing a gap-filled sidecar failed"),
+            }
         }
 
         let name = self.node_name(&uid);
@@ -2295,7 +2330,7 @@ impl Core {
         let reader = CountingReader::new(File::open(&blob)?, &guard).with_cancel(cancel.flag());
         let started = Instant::now();
         let sent = self.block_on_within(
-            link::upload_deadline(meta.len),
+            link::upload_deadline(meta.len, self.transfers.upload_cap()),
             self.drive
                 .upload_new_revision_from(&uid, reader, meta.len as i64, thumbnails, None),
         );
@@ -2753,24 +2788,43 @@ fn waits_for_name(e: &(dyn std::error::Error + 'static)) -> bool {
     std::iter::successors(Some(e), |e| e.source()).any(|e| e.is::<NameHeld>())
 }
 
+/// How long an op waits after its `attempts`-th failure: doubling from
+/// [`DRAIN_BACKOFF_MIN`] up to [`DRAIN_BACKOFF_MAX`], plus up to a fifth more,
+/// different for each op (`seed`), so that ops that failed together are not
+/// all retried in the same second. One that waits for a name (`held`) waits
+/// the minimum.
+///
+/// The doubling stopped at 2^6, 128 s, so the maximum was never reached.
+fn drain_backoff(attempts: i64, held: bool, seed: i64) -> Duration {
+    if held {
+        return DRAIN_BACKOFF_MIN;
+    }
+    let base = DRAIN_BACKOFF_MIN
+        .saturating_mul(1u32 << attempts.clamp(0, 8))
+        .min(DRAIN_BACKOFF_MAX);
+    // A cheap, stable spread: the same op and attempt always wait the same.
+    let spread = (seed.wrapping_mul(0x9E37_79B9).wrapping_add(attempts) as u64 % 21) as u32;
+    base + base * spread / 100
+}
+
 /// How many attempts an op waits for a rename or a create on the wire to free
 /// the name it wants. Two files swapping names each wait for the other, so the
 /// wait has to end; a conflict name ends it.
 const NAME_HOLD_ATTEMPTS: i64 = 4;
 
-/// How much older than its op a remote node may be and still be the one an
-/// unanswered call made. The op is queued the moment the call gives up, so the
-/// node is at most one call's deadline older; the rest is clock skew between
-/// this machine and Proton.
+/// How much older than its op's first send a remote node may be and still be
+/// the one an unanswered call made. The node is made during that call, so it
+/// is at most one call's deadline older; the rest is clock skew between this
+/// machine and Proton.
 const ADOPT_WINDOW_MS: i64 = 2 * 60 * 1000;
 
 /// Whether `twin`, found holding the name a queued create wants, is the node an
-/// earlier, unanswered attempt at that create made: the same kind, created
-/// around when the op was queued, and for a file still empty, as the mount's
+/// earlier, unanswered attempt at that create made: the same kind, created no
+/// earlier than around when the op was first sent (`first_sent_ms`), and for a file still empty, as the mount's
 /// create leaves it, or holding exactly bytes the op uploaded, whose SHA-1 is
 /// one of `sent`.
-fn adoptable(is_dir: bool, twin: &Node, op_created_ms: i64, sent: &[String]) -> bool {
-    if twin.creation_time.saturating_mul(1000) < op_created_ms - ADOPT_WINDOW_MS {
+fn adoptable(is_dir: bool, twin: &Node, first_sent_ms: i64, sent: &[String]) -> bool {
+    if twin.creation_time.saturating_mul(1000) < first_sent_ms - ADOPT_WINDOW_MS {
         return false;
     }
     match &twin.kind {
@@ -3352,6 +3406,22 @@ mod tests {
         }
     }
 
+    #[test]
+    fn a_failing_op_backs_off_to_the_maximum_with_a_spread() {
+        let at = |attempts| drain_backoff(attempts, false, 7);
+        assert!(at(1) >= DRAIN_BACKOFF_MIN * 2);
+        assert!(at(2) > at(1));
+        // Reached, which the doubling capped at 2^6 never did.
+        assert!(at(8) >= DRAIN_BACKOFF_MAX);
+        assert!(at(30) <= DRAIN_BACKOFF_MAX + DRAIN_BACKOFF_MAX / 5);
+        // Ops that failed together do not all come back together.
+        let waits: std::collections::HashSet<_> =
+            (1..=20).map(|id| drain_backoff(8, false, id)).collect();
+        assert!(waits.len() > 5, "{waits:?}");
+        // A wait for a name stays short however often it repeats.
+        assert_eq!(drain_backoff(30, true, 7), DRAIN_BACKOFF_MIN);
+    }
+
     #[test]
     fn only_a_fresh_empty_twin_of_the_same_kind_is_adopted() {
         // The op was queued at t=1000 s, after a create that got no answer.

crates/pdfs-fuse/src/drive.rs

@@ -8,8 +8,10 @@
 //! real client implements it by forwarding, and the simulation tests implement
 //! it with an in-memory Drive that injects Drive's known faults.
 //!
-//! Sharing, Photos, devices, invitations and public links stay on the concrete
-//! client (`Core::client`) until a test needs them faked.
+//! Sharing, Photos, invitations, public links and the rest of the device calls
+//! stay on the concrete client (`Core::client`) until a test needs them faked.
+//! Listing and registering devices are here, so a simulated daemon can sync a
+//! local folder.
 //!
 //! The method names match the client's own, so a call site reads the same
 //! whichever it goes through. The client's generic methods (a reader or writer
@@ -24,9 +26,10 @@ use futures::StreamExt as _;
 use futures::stream::BoxStream;
 use proton_drive_rs::proton_sdk::account::Quota;
 use proton_drive_rs::proton_sdk::error::Result;
-use proton_drive_rs::proton_sdk::ids::{DriveEventId, NodeUid};
+use proton_drive_rs::proton_sdk::ids::{DriveEventId, NodeUid, ShareId};
 use proton_drive_rs::{
-    DriveEvent, DriveEventScopeId, Node, NodeMoveItem, ProtonDriveClient, RevisionReader, Thumbnail,
+    AvailableNameTarget, Device, DeviceType, DriveEvent, DriveEventScopeId, Node, NodeMoveItem,
+    ProtonDriveClient, RevisionReader, Thumbnail, ThumbnailType,
 };
 
 /// One outcome per node of a batch request; see [`ProtonDriveClient::trash_nodes`].
@@ -40,6 +43,8 @@ pub(crate) type OutcomeStream<'a> = BoxStream<'a, Result<(NodeUid, Result<()>)>>
 pub(crate) trait DriveApi: Send + Sync {
     async fn get_my_files_folder(&self) -> Result<Node>;
 
+    async fn context_share_id(&self, uid: &NodeUid) -> Result<ShareId>;
+
     async fn get_node(&self, uid: &NodeUid) -> Result<Option<Node>>;
 
     async fn enumerate_nodes(&self, uids: &[NodeUid]) -> Result<Vec<Node>>;
@@ -113,6 +118,14 @@ pub(crate) trait DriveApi: Send + Sync {
 
     async fn open_revision(&self, uid: &NodeUid) -> Result<Arc<dyn RevisionRead>>;
 
+    /// The file's thumbnail of `thumbnail_type`, or `None` when its revision
+    /// carries none.
+    async fn download_thumbnail(
+        &self,
+        uid: &NodeUid,
+        thumbnail_type: ThumbnailType,
+    ) -> Result<Option<Vec<u8>>>;
+
     async fn download_file_to_dyn(
         &self,
         uid: &NodeUid,
@@ -135,6 +148,22 @@ pub(crate) trait DriveApi: Send + Sync {
 
     async fn move_node(&self, uid: &NodeUid, new_parent: &NodeUid) -> Result<()>;
 
+    /// See [`ProtonDriveClient::copy_node`].
+    async fn copy_node(
+        &self,
+        uid: &NodeUid,
+        new_parent: &NodeUid,
+        name: Option<&str>,
+    ) -> Result<NodeUid>;
+
+    /// See [`ProtonDriveClient::get_available_name`].
+    async fn get_available_name(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        target: AvailableNameTarget,
+    ) -> Result<String>;
+
     fn move_nodes_streaming<'a>(
         &'a self,
         items: Vec<NodeMoveItem>,
@@ -154,6 +183,12 @@ pub(crate) trait DriveApi: Send + Sync {
     /// The account's storage, across every Proton product.
     async fn quota(&self) -> Result<Quota>;
 
+    /// Every computer that backs up to the account.
+    async fn enumerate_devices(&self) -> Result<Vec<Device>>;
+
+    /// Register a computer, with a root folder of its own named `name`.
+    async fn create_device(&self, name: &str, device_type: DeviceType) -> Result<Device>;
+
     /// Called by the drain once it has let go of the blob of an upload to
     /// `uid` that landed, or retired the create that made `uid`, before the
     /// tree has the node, so a simulation can hold it there. Blocks the drain
@@ -280,6 +315,10 @@ impl RevisionRead for RevisionReader {
 
 #[async_trait]
 impl DriveApi for ProtonDriveClient {
+    async fn context_share_id(&self, uid: &NodeUid) -> Result<ShareId> {
+        ProtonDriveClient::context_share_id(self, uid).await
+    }
+
     async fn get_my_files_folder(&self) -> Result<Node> {
         ProtonDriveClient::get_my_files_folder(self).await
     }
@@ -321,7 +360,13 @@ impl DriveApi for ProtonDriveClient {
         name: &str,
         last_modification_time: Option<i64>,
     ) -> Result<NodeUid> {
-        ProtonDriveClient::create_folder(self, parent_uid, name, last_modification_time).await
+        ProtonDriveClient::create_folder(
+            self,
+            parent_uid,
+            name,
+            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
+        )
+        .await
     }
 
     async fn upload_file(
@@ -353,7 +398,7 @@ impl DriveApi for ProtonDriveClient {
             reader,
             intended_size,
             thumbnails,
-            last_modification_time,
+            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
             aead,
         )
         .await
@@ -378,7 +423,7 @@ impl DriveApi for ProtonDriveClient {
             reader,
             intended_size,
             thumbnails,
-            last_modification_time,
+            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
             aead,
         )
         .await
@@ -398,7 +443,7 @@ impl DriveApi for ProtonDriveClient {
             reader,
             intended_size,
             thumbnails,
-            last_modification_time,
+            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
         )
         .await
     }
@@ -408,6 +453,14 @@ impl DriveApi for ProtonDriveClient {
         Ok(Arc::new(reader))
     }
 
+    async fn download_thumbnail(
+        &self,
+        uid: &NodeUid,
+        thumbnail_type: ThumbnailType,
+    ) -> Result<Option<Vec<u8>>> {
+        ProtonDriveClient::download_thumbnail(self, uid, thumbnail_type).await
+    }
+
     async fn download_file_to_dyn(
         &self,
         uid: &NodeUid,
@@ -439,6 +492,24 @@ impl DriveApi for ProtonDriveClient {
         ProtonDriveClient::move_node(self, uid, new_parent).await
     }
 
+    async fn copy_node(
+        &self,
+        uid: &NodeUid,
+        new_parent: &NodeUid,
+        name: Option<&str>,
+    ) -> Result<NodeUid> {
+        ProtonDriveClient::copy_node(self, uid, new_parent, name).await
+    }
+
+    async fn get_available_name(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        target: AvailableNameTarget,
+    ) -> Result<String> {
+        ProtonDriveClient::get_available_name(self, parent_uid, name, target).await
+    }
+
     fn move_nodes_streaming<'a>(
         &'a self,
         items: Vec<NodeMoveItem>,
@@ -470,4 +541,12 @@ impl DriveApi for ProtonDriveClient {
     async fn quota(&self) -> Result<Quota> {
         ProtonDriveClient::quota(self).await
     }
+
+    async fn enumerate_devices(&self) -> Result<Vec<Device>> {
+        ProtonDriveClient::enumerate_devices(self).await
+    }
+
+    async fn create_device(&self, name: &str, device_type: DeviceType) -> Result<Device> {
+        ProtonDriveClient::create_device(self, name, device_type).await
+    }
 }

crates/pdfs-fuse/src/events.rs

@@ -329,6 +329,7 @@ mod tests {
             online: true,
             session_expired: false,
             tokens_unsaved: false,
+            version: "3.3.0".into(),
             pending_uploads: 1,
             pending_changes: 0,
         };

crates/pdfs-fuse/src/filesystem.rs

@@ -261,10 +261,13 @@ impl Filesystem for ProtonFs {
         // in-flight (possibly unsaved) content: authored bytes come from the
         // scratch file, untouched bytes from the base.
         //
-        // This path stays on the dispatch loop. `write` runs there too, so
-        // keeping its reads there as well preserves the ordering the write path
-        // has always had between a write and a read of the same handle; a mostly
-        // local read is not worth reasoning about that for.
+        // Answered on the dispatch loop when everything it needs is on this
+        // machine, which keeps the order `write` has with reads of the same
+        // handle. A base range that has to be downloaded goes to a worker
+        // instead, with the handle as it was when the read came in: the kernel
+        // issued the read before any write that comes after it, so that is
+        // the content it asked for. On the loop, the download held every
+        // request of the mount (`docs/BUGS.md` B227).
         let handle = {
             let st = self.core.state();
             st.active_writes.get(&ino.0).map(|h| {
@@ -279,7 +282,7 @@ impl Filesystem for ProtonFs {
             })
         };
         if let Some((file, len, uid, base_mtime, base_size, written)) = handle {
-            match self.core.serve_open_read(
+            match self.core.serve_open_read_local(
                 &file,
                 len,
                 &uid,
@@ -289,7 +292,25 @@ impl Filesystem for ProtonFs {
                 offset,
                 size as u64,
             ) {
-                Ok(bytes) => reply.data(&bytes),
+                Ok(Some(bytes)) => reply.data(&bytes),
+                Ok(None) => {
+                    let fs = self.clone();
+                    self.core.workers.run(Lane::Transfer, "read", move || {
+                        match fs.core.serve_open_read(
+                            &file,
+                            len,
+                            &uid,
+                            base_mtime,
+                            base_size,
+                            &written,
+                            offset,
+                            size as u64,
+                        ) {
+                            Ok(bytes) => reply.data(&bytes),
+                            Err(e) => reply.error(e),
+                        }
+                    });
+                }
                 Err(e) => reply.error(e),
             }
             return;
@@ -409,58 +430,10 @@ impl Filesystem for ProtonFs {
             reply.error(error);
             return;
         }
-        let fh = fh.0;
-        // Stage the bytes straight into the scratch file (no base download): only
-        // the untouched remainder is pulled from the remote, and only at commit.
-        let file = {
-            let st = self.core.state();
-            match st.handles.get(&fh).and_then(|&i| st.active_writes.get(&i)) {
-                Some(aw) => aw.file.clone(),
-                None => {
-                    reply.error(Errno::EBADF);
-                    return;
-                }
-            }
-        };
-        if let Err(e) = file.write_all_at(data, offset) {
-            error!(ino = ino.0, fh, error = %e, "scratch write failed");
-            // A full local disk is not a broken file: answer `ENOSPC` so the
-            // application can say so (and so `cp`/editors take their own
-            // out-of-space path), and free what the cache is holding — the
-            // scratch file the next write goes to shares that filesystem.
-            if e.raw_os_error() == Some(libc::ENOSPC) {
-                self.core.cache.emergency_evict();
-                reply.error(Errno::ENOSPC);
-            } else {
-                reply.error(Errno::EIO);
-            }
-            return;
+        match self.stage_write(ino.0, fh.0, offset, data) {
+            Ok(()) => reply.written(data.len() as u32),
+            Err(error) => reply.error(error),
         }
-        let new_len = {
-            let mut st = self.core.state();
-            let Some(aw) = st
-                .handles
-                .get(&fh)
-                .copied()
-                .and_then(|i| st.active_writes.get_mut(&i))
-            else {
-                reply.error(Errno::EBADF);
-                return;
-            };
-            aw.record_write(offset, offset + data.len() as u64);
-            let len = aw.len;
-            st.set_size(ino.0, len);
-            len
-        };
-        debug!(
-            ino = ino.0,
-            fh,
-            offset,
-            len = data.len(),
-            new_len,
-            "staged write"
-        );
-        reply.written(data.len() as u32);
     }
 
     #[allow(clippy::too_many_arguments)]
@@ -556,48 +529,62 @@ impl Filesystem for ProtonFs {
             return;
         }
         let new_end = offset.saturating_add(length);
-        let keep_size = (mode & 1) != 0; // FALLOC_FL_KEEP_SIZE
-
-        let is_punch_hole = (mode & 0x02) != 0; // FALLOC_FL_PUNCH_HOLE
-
-        let res = {
+        // Only the modes whose effect on the scratch file this handle can
+        // record. Anything else went through to the scratch file untracked:
+        // a zeroed range was refilled from the base at commit, and a collapse
+        // or insert shifted bytes that `len` and `written` did not follow
+        // (`docs/BUGS.md` B224). `EOPNOTSUPP` is also what makes glibc's
+        // `posix_fallocate` fall back to writing zeros.
+        let Some(kind) = falloc_kind(mode) else {
+            reply.error(Errno::EOPNOTSUPP);
+            return;
+        };
+        let file = {
+            let st = self.core.state();
+            match st.handles.get(&_fh.0).and_then(|i| st.active_writes.get(i)) {
+                Some(aw) => aw.file.clone(),
+                None => {
+                    reply.error(if st.entries.contains_key(&ino.0) {
+                        Errno::EBADF
+                    } else {
+                        Errno::ENOENT
+                    });
+                    return;
+                }
+            }
+        };
+        // The syscall can take a while on a large range; the state lock is
+        // not held across it, as `write` does not hold it across its I/O.
+        let ret = {
+            use std::os::unix::io::AsRawFd;
+            unsafe { libc::fallocate(file.as_raw_fd(), mode, offset as i64, length as i64) }
+        };
+        let res = if ret != 0 {
+            Err(Errno::from(std::io::Error::last_os_error()))
+        } else {
             let mut st = self.core.state();
-            match st
+            if let Some(aw) = st
                 .handles
                 .get(&_fh.0)
                 .copied()
                 .and_then(|i| st.active_writes.get_mut(&i))
             {
-                Some(aw) => {
-                    use std::os::unix::io::AsRawFd;
-                    let fd = aw.file.as_raw_fd();
-                    let ret = unsafe { libc::fallocate(fd, mode, offset as i64, length as i64) };
-                    if ret == 0 {
-                        if is_punch_hole {
-                            // A punched range reads as zero. Mark it authored so
-                            // queue_revision does not refill it from the remote
-                            // baseline and silently undo the hole at commit.
-                            aw.written.add(offset, new_end.min(aw.len));
-                            aw.dirty = true;
-                        } else if !keep_size && new_end > aw.len {
-                            aw.written.add(aw.len, new_end);
-                            aw.len = new_end;
-                            aw.dirty = true;
-                            st.set_size(ino.0, new_end);
-                        }
-                        Ok(())
-                    } else {
-                        Err(Errno::EIO)
-                    }
+                let len = aw.len;
+                let (authored, grown) = kind.effect(offset, new_end, len);
+                if let Some((from, to)) = authored {
+                    // Zeroed or punched bytes read as zero. Marked authored so
+                    // queue_revision does not refill them from the remote
+                    // baseline and silently undo them at commit.
+                    aw.written.add(from, to);
+                    aw.dirty = true;
                 }
-                None => {
-                    if st.entries.contains_key(&ino.0) {
-                        Err(Errno::EBADF)
-                    } else {
-                        Err(Errno::ENOENT)
-                    }
+                if let Some(end) = grown {
+                    aw.len = end;
+                    aw.dirty = true;
+                    st.set_size(ino.0, end);
                 }
             }
+            Ok(())
         };
 
         match res {
@@ -606,18 +593,47 @@ impl Filesystem for ProtonFs {
         }
     }
 
-    /// `close(2)` calls flush before release. The upload is queued in `release`
-    /// and performed in the background, so there is nothing
-    /// to push here — the written bytes are already in the scratch file.
+    /// `close(2)` calls flush before release, and flush is the only one of the
+    /// two whose answer reaches the program: the kernel drops `release`'s. So
+    /// the scratch file of a handle with writes on it is synced here, on a
+    /// worker, and a full disk or a failing one is what `close` returns.
+    ///
+    /// Before, flush answered `ok` at once and `release` synced the file, so an
+    /// `ENOSPC` that delayed allocation held back until then was reported to
+    /// nobody, and the program took the save as done (`docs/BUGS.md` B222).
+    /// It also means `release`, which stays on the dispatch loop for ordering,
+    /// finds the pages already on disk instead of writing back a whole file
+    /// while every other request on the mount waits.
     fn flush(
         &self,
         _req: &Request,
         _ino: INodeNo,
-        _fh: FileHandle,
+        fh: FileHandle,
         _lock_owner: LockOwner,
         reply: ReplyEmpty,
     ) {
-        reply.ok();
+        let file = {
+            let st = self.core.state();
+            st.handles
+                .get(&fh.0)
+                .and_then(|ino| st.active_writes.get(ino))
+                .filter(|aw| aw.dirty)
+                .map(|aw| aw.file.clone())
+        };
+        let Some(file) = file else {
+            reply.ok();
+            return;
+        };
+        let fs = self.clone();
+        self.core
+            .workers
+            .run(Lane::Transfer, "flush", move || match file.sync_data() {
+                Ok(()) => reply.ok(),
+                Err(e) => {
+                    error!(fh = fh.0, error = %e, "flush of scratch file failed");
+                    reply.error(fs.scratch_sync_errno(&e));
+                }
+            });
     }
 
     /// Durability here means the scratch file, not the remote: a caller asking
@@ -655,7 +671,7 @@ impl Filesystem for ProtonFs {
         reply: ReplyEmpty,
     ) {
         let ino = self.tree(ino);
-        let (handle, unlinked_uid) = {
+        let (handle, unlinked_uid, releasing) = {
             let mut st = self.core.state();
             let unlinked_uid = release_unlinked_entry(&mut st, ino.0);
             let ino = st.handles.remove(&fh.0);
@@ -668,7 +684,11 @@ impl Filesystem for ProtonFs {
                     None
                 }
             });
-            (h, unlinked_uid)
+            let releasing = ino.filter(|_| h.is_some());
+            if let Some(ino) = releasing {
+                st.releasing.insert(ino);
+            }
+            (h, unlinked_uid, releasing)
         };
         // Deliberately **not** handed to a worker, unlike the other slow
         // handlers here. The kernel does not wait for a `release` reply before
@@ -685,6 +705,9 @@ impl Filesystem for ProtonFs {
         // finish it (audit F1). What is left is a rename, two fsyncs, a database
         // insert, and at most a bounded copy out of the local cache.
         self.finish_release(handle, unlinked_uid, reply);
+        if let Some(ino) = releasing {
+            self.core.state().releasing.remove(&ino);
+        }
     }
 
     fn unlink(&self, _req: &Request, parent: INodeNo, name: &OsStr, reply: ReplyEmpty) {
@@ -952,20 +975,59 @@ impl Filesystem for ProtonFs {
     fn copy_file_range(
         &self,
         _req: &Request,
-        _ino_in: INodeNo,
+        ino_in: INodeNo,
         _fh_in: FileHandle,
-        _offset_in: u64,
-        _ino_out: INodeNo,
-        _fh_out: FileHandle,
-        _offset_out: u64,
-        _len: u64,
-        _flags: CopyFileRangeFlags,
+        offset_in: u64,
+        ino_out: INodeNo,
+        fh_out: FileHandle,
+        offset_out: u64,
+        len: u64,
+        flags: CopyFileRangeFlags,
         reply: ReplyWrite,
     ) {
-        // Also must stay ENOSYS: there is no server-side copy, and this is the
-        // errno that sends coreutils (and the kernel) down the read/write path
-        // instead of failing the copy outright.
-        reply.error(Errno::ENOSYS);
+        // Copied here when the source bytes are on this machine, as `write`
+        // would stage them, minus a FUSE round trip per page: `cp` of a cached
+        // 256 MiB file ran at about 100 MiB/s through read and write. Anything
+        // that would have to be downloaded gets `EOPNOTSUPP`, which makes the
+        // kernel copy that one call through read and write itself; `ENOSYS`
+        // would turn the op off for the whole mount. There is no server-side
+        // copy into a file `cp` has already created, so the copy still uploads.
+        //
+        // On the dispatch loop, like `write`, so it keeps its order with the
+        // reads and writes of the same handle. [`COPY_RANGE_MAX`] bounds how
+        // long one call holds the loop.
+        let (ino_in, ino_out) = (self.tree(ino_in), self.tree(ino_out));
+        if !flags.is_empty() || ino_in == ino_out {
+            reply.error(Errno::EOPNOTSUPP);
+            return;
+        }
+        if let Err(error) = self.core.require_writable(ino_out.0) {
+            reply.error(error);
+            return;
+        }
+        let bytes = match self
+            .core
+            .read_local(ino_in.0, offset_in, len.min(COPY_RANGE_MAX))
+        {
+            Ok(Some(bytes)) => bytes,
+            Ok(None) => {
+                debug!(ino_in = ino_in.0, offset_in, "copy range not local");
+                reply.error(Errno::EOPNOTSUPP);
+                return;
+            }
+            Err(error) => {
+                reply.error(error);
+                return;
+            }
+        };
+        if bytes.is_empty() {
+            reply.written(0);
+            return;
+        }
+        match self.stage_write(ino_out.0, fh_out.0, offset_out, &bytes) {
+            Ok(()) => reply.written(bytes.len() as u32),
+            Err(error) => reply.error(error),
+        }
     }
 }
 
@@ -993,6 +1055,11 @@ pub struct ProtonFs {
 /// worker busy indefinitely.
 const OPEN_BASE_ATTEMPTS: u32 = 3;
 
+/// The most one `copy_file_range` call copies; the caller loops for the rest.
+/// A local copy of this much takes milliseconds, which is how long it holds
+/// the dispatch loop.
+const COPY_RANGE_MAX: u64 = 16 * 1024 * 1024;
+
 /// One directory's entries as `readdir` reports them: `.` and `..` first, then
 /// the interned children in `children` order.
 ///
@@ -1022,6 +1089,52 @@ fn build_listing(st: &State, ino: u64) -> DirListing {
 /// The cookie handed back is the index of the *next* entry, so a resumed call
 /// continues exactly where the last one stopped — which is only true because
 /// the listing behind those indexes is a snapshot (`docs/BUGS.md` B43).
+/// What an `fallocate` mode does to a write handle, for the modes it can
+/// record (`docs/BUGS.md` B224).
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum FallocKind {
+    /// Reserve space; past the end it grows the file unless `keep_size`.
+    Allocate { keep_size: bool },
+    /// Deallocate a range inside the file, which then reads as zero.
+    Punch,
+    /// Zero a range; past the end it grows the file unless `keep_size`.
+    Zero { keep_size: bool },
+}
+
+fn falloc_kind(mode: i32) -> Option<FallocKind> {
+    const KEEP: i32 = libc::FALLOC_FL_KEEP_SIZE;
+    const PUNCH: i32 = libc::FALLOC_FL_PUNCH_HOLE;
+    const ZERO: i32 = libc::FALLOC_FL_ZERO_RANGE;
+    match mode {
+        0 => Some(FallocKind::Allocate { keep_size: false }),
+        KEEP => Some(FallocKind::Allocate { keep_size: true }),
+        m if m == PUNCH | KEEP => Some(FallocKind::Punch),
+        ZERO => Some(FallocKind::Zero { keep_size: false }),
+        m if m == ZERO | KEEP => Some(FallocKind::Zero { keep_size: true }),
+        _ => None,
+    }
+}
+
+impl FallocKind {
+    /// For `[offset, end)` on a file `len` bytes long: the range that now
+    /// reads as zero and must count as written, and the new length if it grew.
+    fn effect(self, offset: u64, end: u64, len: u64) -> (Option<(u64, u64)>, Option<u64>) {
+        let grow = |keep_size: bool| (!keep_size && end > len).then_some(end);
+        let zeroed = |to: u64| (offset < to).then_some((offset, to));
+        match self {
+            // Space past the old end reads as zero, and nothing before it moved.
+            Self::Allocate { keep_size } => {
+                (grow(keep_size).map(|end| (len, end)), grow(keep_size))
+            }
+            Self::Punch => (zeroed(end.min(len)), None),
+            Self::Zero { keep_size } => {
+                let to = if keep_size { end.min(len) } else { end };
+                (zeroed(to), grow(keep_size))
+            }
+        }
+    }
+}
+
 fn reply_listing(listing: &DirListing, offset: u64, root: u64, mut reply: ReplyDirectory) {
     for (i, (ino, is_dir, name)) in listing.iter().enumerate().skip(offset as usize) {
         let ft = if *is_dir {
@@ -1321,6 +1434,14 @@ impl ProtonFs {
                     // (`ContentCache::clone_or_copy`).
                     if let Err(e) = ContentCache::clone_or_copy(&pending.path, &path) {
                         let _ = std::fs::remove_file(&path);
+                        // The drain lets go of the pending entry before it
+                        // discards the blob, so a blob that went away under the
+                        // copy is a revision that landed or was replaced: the
+                        // same race the re-check below catches, only earlier.
+                        if self.core.pending_blob(&uid).as_ref() != Some(&pending.path) {
+                            warn!(%uid, attempt, "queued revision went away while opening for write; retrying");
+                            continue;
+                        }
                         error!(%uid, source = %pending.path.display(), error = %e,
                             "copy queued revision into write scratch failed");
                         break 'install Err(Errno::EIO);
@@ -1435,6 +1556,20 @@ impl ProtonFs {
     }
 
     /// The body of [`Filesystem::fsync`], run off the dispatch loop.
+    /// The errno to give a program for a failed sync of a scratch file.
+    /// Delayed allocation means a full disk usually surfaces at the sync
+    /// rather than at `write(2)`, and `ENOSPC` is what a program checks for.
+    fn scratch_sync_errno(&self, e: &std::io::Error) -> Errno {
+        match e.raw_os_error() {
+            Some(libc::ENOSPC) => {
+                self.core.cache.emergency_evict();
+                Errno::ENOSPC
+            }
+            Some(libc::EDQUOT) => Errno::EDQUOT,
+            _ => Errno::EIO,
+        }
+    }
+
     fn serve_fsync(&self, fh: FileHandle, reply: ReplyEmpty) {
         // Everything the durability sidecar needs, copied out so no lock is held
         // across the sync.
@@ -1455,22 +1590,18 @@ impl ProtonFs {
                 )
             })
         };
+        // A handle opened for reading has nothing of its own to make durable,
+        // and POSIX allows `fsync` on it; `EBADF` failed `sync FILE` and
+        // backup tools that sync what they read (`docs/BUGS.md` B222).
         let Some((f, path, uid, dirty, written, len, base_size, base_mtime, base_revision_id)) =
             handle
         else {
-            reply.error(Errno::EBADF);
+            reply.ok();
             return;
         };
         if let Err(e) = f.sync_all() {
             error!(fh = fh.0, error = %e, "fsync of scratch file failed");
-            // Delayed allocation means a full disk usually surfaces here rather
-            // than at `write(2)`; `ENOSPC` is what an application checks for.
-            if e.raw_os_error() == Some(libc::ENOSPC) {
-                self.core.cache.emergency_evict();
-                reply.error(Errno::ENOSPC);
-            } else {
-                reply.error(Errno::EIO);
-            }
+            reply.error(self.scratch_sync_errno(&e));
             return;
         }
         // A clean handle has nothing on it that the remote does not already
@@ -1521,6 +1652,48 @@ impl ProtonFs {
     }
 
     /// The body of [`Filesystem::create`], run off the dispatch loop.
+    /// Stage `data` at `offset` of the write handle `fh` on `ino`, straight into
+    /// its scratch file (no base download): only the untouched remainder is
+    /// pulled from the remote, and only at commit.
+    fn stage_write(&self, ino: u64, fh: u64, offset: u64, data: &[u8]) -> Result<(), Errno> {
+        let file = {
+            let st = self.core.state();
+            match st.handles.get(&fh).and_then(|&i| st.active_writes.get(&i)) {
+                Some(aw) => aw.file.clone(),
+                None => return Err(Errno::EBADF),
+            }
+        };
+        if let Err(e) = file.write_all_at(data, offset) {
+            error!(ino, fh, error = %e, "scratch write failed");
+            // A full local disk is not a broken file: answer `ENOSPC` so the
+            // application can say so (and so `cp`/editors take their own
+            // out-of-space path), and free what the cache is holding — the
+            // scratch file the next write goes to shares that filesystem.
+            if e.raw_os_error() == Some(libc::ENOSPC) {
+                self.core.cache.emergency_evict();
+                return Err(Errno::ENOSPC);
+            }
+            return Err(Errno::EIO);
+        }
+        let new_len = {
+            let mut st = self.core.state();
+            let Some(aw) = st
+                .handles
+                .get(&fh)
+                .copied()
+                .and_then(|i| st.active_writes.get_mut(&i))
+            else {
+                return Err(Errno::EBADF);
+            };
+            aw.record_write(offset, offset + data.len() as u64);
+            let len = aw.len;
+            st.set_size(ino, len);
+            len
+        };
+        debug!(ino, fh, offset, len = data.len(), new_len, "staged write");
+        Ok(())
+    }
+
     fn serve_create(&self, parent: u64, name: &str, reply: ReplyCreate) {
         if let Err(error) = self.core.require_writable(parent) {
             reply.error(error);
@@ -1717,9 +1890,7 @@ impl ProtonFs {
         // empty, which it is, so reads stay offline-clean across a restart too.
         if local {
             st.children.insert(ino, Vec::new());
-            if let Err(e) = self.core.db.set_listed(&uid, true) {
-                warn!(%uid, error = %e, "db set_listed(true) failed for local folder");
-            }
+            st.record_listed(uid);
         }
         let entry = st.entries.get(&ino).unwrap();
         let attr = self.attr(ino, &entry.node, entry.access);
@@ -2205,7 +2376,7 @@ impl ProtonFs {
         // regardless — the file is gone from their point of view the moment the
         // command returns. The same when the network goes
         // away under the remote call below.
-        let queue_it = |reply: ReplyEmpty| match self.core.queue_trash(&uid, name) {
+        let queue_it = |reply: ReplyEmpty| match self.core.queue_trash(&uid, name, open_now) {
             Ok(()) => reply.ok(),
             Err(e) => reply.error(e),
         };
@@ -2337,3 +2508,60 @@ impl ProtonFs {
         }
     }
 }
+
+#[cfg(test)]
+mod falloc_tests {
+    use super::*;
+
+    #[test]
+    fn only_the_modes_a_handle_can_record_are_accepted() {
+        let keep = libc::FALLOC_FL_KEEP_SIZE;
+        assert_eq!(
+            falloc_kind(0),
+            Some(FallocKind::Allocate { keep_size: false })
+        );
+        assert_eq!(
+            falloc_kind(keep),
+            Some(FallocKind::Allocate { keep_size: true })
+        );
+        assert_eq!(
+            falloc_kind(libc::FALLOC_FL_PUNCH_HOLE | keep),
+            Some(FallocKind::Punch)
+        );
+        assert_eq!(
+            falloc_kind(libc::FALLOC_FL_ZERO_RANGE),
+            Some(FallocKind::Zero { keep_size: false })
+        );
+        for mode in [
+            libc::FALLOC_FL_PUNCH_HOLE,
+            libc::FALLOC_FL_COLLAPSE_RANGE,
+            libc::FALLOC_FL_INSERT_RANGE,
+            libc::FALLOC_FL_UNSHARE_RANGE,
+        ] {
+            assert_eq!(falloc_kind(mode), None, "{mode:#x}");
+        }
+    }
+
+    /// A zeroed range was left unwritten, so the commit filled it back in
+    /// from the remote base (`docs/BUGS.md` B224).
+    #[test]
+    fn a_zeroed_or_punched_range_counts_as_written() {
+        let zero = FallocKind::Zero { keep_size: false };
+        assert_eq!(zero.effect(10, 20, 100), (Some((10, 20)), None));
+        assert_eq!(zero.effect(90, 120, 100), (Some((90, 120)), Some(120)));
+        let zero_keep = FallocKind::Zero { keep_size: true };
+        assert_eq!(zero_keep.effect(90, 120, 100), (Some((90, 100)), None));
+        assert_eq!(
+            FallocKind::Punch.effect(90, 120, 100),
+            (Some((90, 100)), None)
+        );
+        assert_eq!(FallocKind::Punch.effect(120, 130, 100), (None, None));
+        let alloc = FallocKind::Allocate { keep_size: false };
+        assert_eq!(alloc.effect(0, 50, 100), (None, None));
+        assert_eq!(alloc.effect(90, 120, 100), (Some((100, 120)), Some(120)));
+        assert_eq!(
+            FallocKind::Allocate { keep_size: true }.effect(90, 120, 100),
+            (None, None)
+        );
+    }
+}

crates/pdfs-fuse/src/keeper.rs

@@ -0,0 +1,271 @@
+//! Keeping pinned files on this computer after they were pinned.
+//!
+//! A pin downloads a file once. Nothing downloaded it again afterwards: a
+//! change from another device deleted the cached copy, a file added to a
+//! pinned folder elsewhere was never fetched, and a download that failed while
+//! the link was down stayed failed. Each of those left a file listed as kept
+//! offline that the next read downloaded, and that could not be read at all
+//! without a network (`docs/BUGS.md` B282).
+//!
+//! The keeper is one thread that checks pins again and downloads what is
+//! missing or stale: every pin when the daemon starts and when the link comes
+//! back, and the pins a batch of remote events touched once the batch is
+//! applied. A remote change no longer deletes a pinned file's copy. The copy
+//! is stored under the revision's `(mtime, size)`, so a read of a newer
+//! revision does not take it, and the keeper replaces it once the new one is
+//! downloaded.
+
+use std::collections::HashSet;
+use std::time::{Duration, Instant};
+
+use proton_drive_rs::NodeKind;
+use proton_drive_rs::proton_sdk::ids::NodeUid;
+use tracing::{debug, info, warn};
+
+use super::{Core, is_local_uid, node_size, parse_uid};
+
+/// How often the keeper looks for work.
+const KEEPER_TICK: Duration = Duration::from_secs(1);
+/// The first wait before a check that could not download everything is tried
+/// again. It doubles on every failure, up to [`RETRY_MAX`].
+const RETRY_FIRST: Duration = Duration::from_secs(30);
+const RETRY_MAX: Duration = Duration::from_secs(30 * 60);
+
+/// What the keeper owes a check.
+#[derive(Debug, Default)]
+pub(crate) struct PinWork {
+    /// Every pin.
+    all: bool,
+    /// The pinned files and folders named here. A folder is checked whole.
+    nodes: HashSet<NodeUid>,
+}
+
+impl PinWork {
+    fn is_empty(&self) -> bool {
+        !self.all && self.nodes.is_empty()
+    }
+
+    fn merge(&mut self, other: PinWork) {
+        self.all |= other.all;
+        self.nodes.extend(other.nodes);
+    }
+}
+
+/// A file a pin keeps, as the tree knows it now.
+pub(crate) struct KeptFile {
+    pub(crate) uid: NodeUid,
+    pub(crate) name: String,
+    pub(crate) mtime: i64,
+    pub(crate) size: u64,
+}
+
+impl Core {
+    /// Have the keeper check every pin.
+    pub(crate) fn recheck_all_pins(&self) {
+        self.pin_work.lock().all = true;
+    }
+
+    /// Have the keeper check the pinned file or folder `uid`.
+    pub(crate) fn recheck_pinned(&self, uid: &NodeUid) {
+        self.pin_work.lock().nodes.insert(uid.clone());
+    }
+
+    /// The keeper's loop, until the daemon stops. Starts with a check of every
+    /// pin, which catches up on whatever changed while the daemon was down.
+    ///
+    /// Work that failed waits out a backoff of its own. New work does not wait
+    /// for it, so a file that keeps failing does not hold up the next change.
+    pub(crate) fn run_pin_keeper(&self) {
+        self.recheck_all_pins();
+        let mut backlog = PinWork::default();
+        let mut backlog_due = Instant::now();
+        let mut retry = RETRY_FIRST;
+        while self.shutdown.sleep(KEEPER_TICK) {
+            if !self.is_online() {
+                continue;
+            }
+            let mut work = std::mem::take(&mut *self.pin_work.lock());
+            let retrying = !backlog.is_empty() && Instant::now() >= backlog_due;
+            if retrying {
+                work.merge(std::mem::take(&mut backlog));
+            }
+            if work.is_empty() {
+                continue;
+            }
+            let failed = self.keep_pins(&work);
+            if failed.is_empty() {
+                if retrying {
+                    retry = RETRY_FIRST;
+                }
+                continue;
+            }
+            backlog.merge(failed);
+            backlog_due = Instant::now() + retry;
+            retry = (retry * 2).min(RETRY_MAX);
+        }
+    }
+
+    /// Download every file `work` covers whose cached copy is missing or
+    /// stale. Returns what could not be checked or downloaded.
+    fn keep_pins(&self, work: &PinWork) -> PinWork {
+        let mut failed = PinWork::default();
+        let roots: Vec<NodeUid> = if work.all {
+            self.cache
+                .list_pins()
+                .iter()
+                .filter_map(|pin| parse_uid(&pin.uid))
+                .chain(work.nodes.iter().cloned())
+                .collect()
+        } else {
+            work.nodes.iter().cloned().collect()
+        };
+        let mut seen: HashSet<u64> = HashSet::new();
+        let mut files: Vec<u64> = Vec::new();
+        for uid in roots {
+            if self.shutdown.is_stopping() {
+                return failed;
+            }
+            if !self.cache.is_pinned(&uid) {
+                continue;
+            }
+            let found = {
+                let st = self.state();
+                st.by_uid.get(&uid).and_then(|&ino| {
+                    let e = st.entries.get(&ino)?;
+                    Some((ino, e.parent, e.node.is_folder()))
+                })
+            };
+            let Some((ino, parent, is_folder)) = found else {
+                debug!(%uid, "pin keeper: pinned node is not in the tree");
+                continue;
+            };
+            if is_folder {
+                match self.pin_subtree_files(ino) {
+                    Ok(inos) => files.extend(inos.into_iter().filter(|i| seen.insert(*i))),
+                    Err(e) => {
+                        warn!(%uid, error = %e, "pin keeper: listing a kept folder failed");
+                        failed.nodes.insert(uid);
+                    }
+                }
+                continue;
+            }
+            // An event about this file dropped its parent's listing. Listing
+            // it again brings the file's entry up to the revision Drive has
+            // now, which is what the cached copy is checked against.
+            if !work.all
+                && parent != ino
+                && let Err(e) = self.ensure_children(parent)
+            {
+                warn!(%uid, error = ?e, "pin keeper: listing a kept file's folder failed");
+                failed.nodes.insert(uid);
+                continue;
+            }
+            if seen.insert(ino) {
+                files.push(ino);
+            }
+        }
+
+        let stale: Vec<KeptFile> = files
+            .into_iter()
+            .filter_map(|ino| self.kept_file(ino))
+            .filter(|f| !self.cache.is_cached(&f.uid, f.mtime, f.size))
+            .collect();
+        if stale.is_empty() {
+            return failed;
+        }
+        let job = self.transfers.begin_job("Updating files kept offline");
+        job.set_total(stale.len() as u64);
+        let (mut fetched, mut failures) = (0usize, 0usize);
+        for file in stale {
+            if self.shutdown.is_stopping() {
+                break;
+            }
+            // Unpinned while the check ran.
+            if !self.cache.is_pinned(&file.uid) {
+                job.step();
+                continue;
+            }
+            job.detail(file.name.clone());
+            match self.fetch_pinned(&file.uid, &file.name, file.mtime, file.size) {
+                Ok(()) => fetched += 1,
+                Err(e) => {
+                    warn!(uid = %file.uid, error = %e, "pin keeper: download failed");
+                    failed.nodes.insert(file.uid);
+                    failures += 1;
+                }
+            }
+            job.step();
+        }
+        info!(
+            fetched,
+            failed = failures,
+            "pin keeper: brought files kept offline up to date"
+        );
+        failed
+    }
+
+    /// The file at `ino`, as a pin keeps it. `None` for a folder, a file this
+    /// daemon still owes an upload for, or a file whose real size cannot be
+    /// read.
+    ///
+    /// A queued write is ahead of Drive. Downloading Drive's revision would
+    /// cache what the write replaces, and the drain keeps the uploaded bytes
+    /// of a pinned file once they land.
+    ///
+    /// A listing carries the ciphertext size until its size upgrade lands
+    /// (B12). Stored under that size, the copy never matched the plaintext it
+    /// holds, so every read downloaded the file again and every check
+    /// downloaded it once more.
+    pub(crate) fn kept_file(&self, ino: u64) -> Option<KeptFile> {
+        let (uid, name, mtime, size, provisional) = {
+            let st = self.state();
+            let e = st.entries.get(&ino)?;
+            let NodeKind::File { claimed_size, .. } = &e.node.kind else {
+                return None;
+            };
+            (
+                e.uid.clone(),
+                e.node.name.clone(),
+                e.node.modification_time,
+                node_size(&e.node),
+                claimed_size.is_none(),
+            )
+        };
+        if is_local_uid(&uid) || self.pending.lock().contains_key(&uid) {
+            return None;
+        }
+        let size = match provisional {
+            true => self.resolve_provisional_size(ino, &uid)?,
+            false => size,
+        };
+        Some(KeptFile {
+            uid,
+            name,
+            mtime,
+            size,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn work_that_failed_keeps_every_node_and_the_full_check() {
+        let mut backlog = PinWork::default();
+        assert!(backlog.is_empty());
+        let uid = parse_uid("vol~a").unwrap();
+        backlog.merge(PinWork {
+            all: false,
+            nodes: HashSet::from([uid.clone()]),
+        });
+        backlog.merge(PinWork {
+            all: true,
+            nodes: HashSet::from([uid.clone()]),
+        });
+        assert!(backlog.all);
+        assert_eq!(backlog.nodes.len(), 1);
+        assert!(!backlog.is_empty());
+    }
+}

crates/pdfs-fuse/src/lib.rs

@@ -74,11 +74,12 @@ use proton_drive_rs::proton_sdk::api::ResponseCode;
 use proton_drive_rs::proton_sdk::error::ProtonError;
 use proton_drive_rs::proton_sdk::ids::{DriveEventId, LinkId, NodeUid, ShareId, VolumeId};
 use proton_drive_rs::{
-    DriveEvent, DriveEventScopeId, MemberRole, Node, NodeKind, NodeMoveItem, ProtonDriveClient,
-    ProtonPhotosClient, SharedWithMeItem, ThumbnailType,
+    AvailableNameTarget, DriveEvent, DriveEventScopeId, MemberRole, Node, NodeKind, NodeMoveItem,
+    ProtonDriveClient, ProtonPhotosClient, SharedWithMeItem, ThumbnailType,
 };
 
 mod albums;
+mod attach;
 mod background;
 mod conflicts;
 mod control;
@@ -90,6 +91,7 @@ mod drive;
 use drive::{DriveApi, RevisionRead};
 mod events;
 mod filesystem;
+mod keeper;
 mod link;
 pub use filesystem::ProtonFs;
 mod mount;
@@ -116,14 +118,16 @@ mod upload;
 mod r#virtual;
 mod workers;
 use background::{forget_and_notify, run_event_sync, run_local_index, run_photos_event_sync};
+use link::BATCH_CALL_TIMEOUT;
 pub(crate) use mount::is_stale_mount;
+pub use mount::prepare_mountpoint;
 pub use mount::{MountOptions, MountOutcome, mount};
 use mount::{
     SecondaryInsertRejection, SecondaryMount, clear_stale_mount, fuse_connection_id, spawn_session,
 };
 use reads::{BlockFlight, BlockRing, PREFETCH_BUDGET, Prefetch, ReaderSlot, STREAM_BYPASS_MIN};
 use state::{Entry, Intervals, PendingRevision, State, StateGuard, WriteHandle};
-pub use systemd::idle_sleep;
+pub use systemd::{idle_sleep, status as notify_status, stretch_watchdog_for_startup};
 use tracing::{debug, error, info, warn};
 use transfers::{CountingWriter, JobGuard, OwnedCountingReader, TransferRegistry};
 use r#virtual::{
@@ -586,6 +590,8 @@ struct Core {
     /// Nudges the drain workers: set true and notify to have them re-examine
     /// the queue instead of waiting out their backoff.
     drain_wake: Arc<(Mutex<bool>, Condvar)>,
+    /// The pins the keeper owes a check (`keeper`).
+    pin_work: Arc<Mutex<keeper::PinWork>>,
     /// The daemon's stop signal, shared with every background loop this `Core`
     /// was cloned into so teardown can end and join them (`docs/BUGS.md` B44).
     shutdown: Arc<shutdown::Shutdown>,
@@ -727,6 +733,8 @@ struct Core {
     /// can say what a pass is doing rather than just "syncing". An entry exists
     /// only while that folder's reconcile pass is running.
     sync_progress: Arc<Mutex<HashMap<i64, SyncProgress>>>,
+    /// Whether the folder-sync engine is alive, and which pass it is on.
+    sync_engine: Arc<sync::EngineHealth>,
     /// Channel to the folder-sync engine: nudges it to
     /// reconcile a folder, reconcile everything, or re-scan its watch set.
     sync_tx: std::sync::mpsc::Sender<sync::SyncMsg>,
@@ -2120,12 +2128,39 @@ impl Core {
         }
     }
 
-    /// Whether `ino`'s listing is already in memory, i.e. whether
-    /// [`Core::ensure_children`] would return without touching the network.
-    /// Lets a handler decide between answering inline and handing off to a
-    /// worker, at the cost of one uncontended map lookup.
+    /// Whether [`Core::ensure_children`] would answer for `ino` without
+    /// touching the network. Lets a handler decide between answering inline
+    /// and handing off to a worker.
+    ///
+    /// A resident listing is not enough on its own. A shared folder's, or the
+    /// Shared with me root's, is fetched again once it is a minute old, and
+    /// that fetch ran on the dispatch loop, so every request on the mount
+    /// waited for Drive to answer (`docs/BUGS.md` B219).
     fn children_cached(&self, ino: u64) -> bool {
-        self.state().children.contains_key(&ino)
+        let (uid, resident) = {
+            let st = self.state();
+            match st.entries.get(&ino) {
+                Some(e) => (e.uid.clone(), st.children.contains_key(&ino)),
+                // `list_children` answers ENOENT without the network.
+                None => return true,
+            }
+        };
+        if !resident {
+            return false;
+        }
+        let freshness = if is_virtual_uid(&uid) {
+            Some(SHARED_WITH_ME_SYNCED_MS.to_string())
+        } else if !self.is_own_or_virtual(&uid) && !is_local_uid(&uid) {
+            Some(Self::shared_folder_freshness_key(&uid))
+        } else {
+            None
+        };
+        freshness.is_none_or(|key| {
+            !listing_needs_refresh(
+                self.online.load(Ordering::Relaxed),
+                self.shared_listing_stale(&key),
+            )
+        })
     }
 
     /// Re-apply the optimistic size of any queued write to `nodes`.
@@ -2293,8 +2328,7 @@ impl Core {
 
         let generation = self.shared_generation.load(Ordering::SeqCst);
         let accepted = accepted_share_provenance(
-            self.rt
-                .block_on(self.client.enumerate_shared_with_me())
+            self.block_on_within(BATCH_CALL_TIMEOUT, self.client.enumerate_shared_with_me())
                 .map_err(|error| {
                     error!(%error, "enumerating shared roots failed");
                     Errno::EIO
@@ -2303,12 +2337,14 @@ impl Core {
         let nodes = if accepted.uids.is_empty() {
             Vec::new()
         } else {
-            self.rt
-                .block_on(self.drive.enumerate_nodes_light(&accepted.uids))
-                .map_err(|error| {
-                    error!(%error, "materializing shared roots failed");
-                    Errno::EIO
-                })?
+            self.block_on_within(
+                BATCH_CALL_TIMEOUT,
+                self.drive.enumerate_nodes_light(&accepted.uids),
+            )
+            .map_err(|error| {
+                error!(%error, "materializing shared roots failed");
+                Errno::EIO
+            })?
         };
         let virtual_uid = shared_with_me_uid();
         let published = prepare_shared_roots(&accepted, nodes, &virtual_uid);
@@ -2687,6 +2723,7 @@ impl Core {
             return Ok(());
         }
 
+        let preassigned = state::inos_for(&self.db, &filtered_nodes);
         let mut st = self.state();
         // Lost the race? Another thread already populated it.
         if st.children.contains_key(&ino) {
@@ -2708,15 +2745,14 @@ impl Core {
             })
             .map(|n| n.uid.clone())
             .collect();
-        let inos = st.intern_batch(ino, filtered_nodes);
+        let inos = st.intern_batch_with_inos(ino, filtered_nodes, preassigned);
         child_inos.extend(inos);
         st.children.insert(ino, child_inos);
         let root_snapshot = primary_root.then(|| RootListingSnapshot::capture(&st, ino).unwrap());
         // Record the listing as complete so a later restart (or a trimmed hot
-        // cache) can rebuild it from the DB without the API.
-        if let Err(e) = self.db.set_listed(&folder_uid, true) {
-            warn!(%folder_uid, error = %e, "db set_listed(true) failed");
-        }
+        // cache) can rebuild it from the DB without the API. Written with the
+        // children's rows when the lock goes, not under it.
+        st.record_listed(folder_uid.clone());
         drop(st);
         self.flush_access_changes();
         if let Some(snapshot) = root_snapshot {
@@ -2879,7 +2915,8 @@ impl Core {
         let (mut key, mut uids, mut slot) = (key, uids, slot);
         loop {
             for chunk in uids.chunks(SIZE_UPGRADE_CHUNK) {
-                let result = self.rt.block_on(self.drive.enumerate_nodes(chunk));
+                let result =
+                    self.block_on_within(BATCH_CALL_TIMEOUT, self.drive.enumerate_nodes(chunk));
                 self.apply_size_upgrade(key, result);
                 slot.chunk_done();
             }
@@ -3131,6 +3168,28 @@ impl Core {
         )
     }
 
+    /// [`Core::resolve_anywhere`], widened to the Photos timeline for sharing.
+    ///
+    /// A photo lives on the photos volume, which no location shows, so the
+    /// residency proof above never finds it. The timeline in the `photos` table
+    /// is this daemon's proof instead: it lists only photos on the user's own
+    /// volume, which are theirs to share. A photo in an album someone else
+    /// shared is not in it and stays refused.
+    pub(crate) fn resolve_shareable(&self, uid: &str) -> CoreResult<NodeUid> {
+        resolve_anywhere_with(
+            uid,
+            |uid| self.owns_visible_uid(uid),
+            |uid| {
+                let uid = uid.to_string();
+                Ok(self.db.mirror_contains_uid(&uid)?
+                    || !self
+                        .db
+                        .photos_by_uid(std::slice::from_ref(&uid))?
+                        .is_empty())
+            },
+        )
+    }
+
     fn source_parent_uid(&self, ino: u64, rel: &Path) -> CoreResult<NodeUid> {
         let state = self.state();
         let entry = state
@@ -3967,7 +4026,12 @@ impl Core {
     /// the cached ones, as when the trash is sent at once: a partial write
     /// fills its gaps from them, offline too (`docs/BUGS.md` B186). The final
     /// close or the trash landing, whichever comes last, lets go of them.
-    fn queue_trash(&self, uid: &NodeUid, name: &str) -> Result<(), Errno> {
+    ///
+    /// `open` is whether the caller found the file open. A create that landed
+    /// under a delete is trashed by its real uid before the tree has it, so
+    /// asking the tree alone took an open file for closed (`docs/BUGS.md`
+    /// B257).
+    fn queue_trash(&self, uid: &NodeUid, name: &str, open: bool) -> Result<(), Errno> {
         self.require_uid_writable(uid)?;
         // The bytes below are about to be discarded, and a drain worker may be
         // reading them onto the wire right now. Stop it first: with several
@@ -3982,7 +4046,7 @@ impl Core {
                 error!(%uid, error = %e, "queueing trash failed");
                 Errno::EIO
             })?;
-        let open_now = self.is_open_anywhere(uid);
+        let open_now = open || self.is_open_anywhere(uid);
         if open_now {
             let read_from = self.pending_blob(uid);
             self.release_dropped_below(
@@ -4227,9 +4291,16 @@ impl Core {
     }
 
     /// Pin the node at mountpoint-relative `rel`. A file downloads its full
-    /// plaintext into the content cache; a folder records a recursive pin and
-    /// downloads every descendant file (selective sync). Returns a human message.
-    fn pin(&self, rel: &Path) -> CoreResult<String> {
+    /// plaintext into the content cache before this returns. A folder records a
+    /// recursive pin and downloads every descendant file on a background thread,
+    /// reported as a job: a big folder far outlasts the socket read timeout.
+    /// Returns a human message.
+    ///
+    /// `recorded` is the path the pin registry keeps for the front ends to
+    /// open the pin by: `rel` itself on the primary mount, which they join to
+    /// the mountpoint, and the absolute local path on an on-demand folder's
+    /// mount, whose node is not reachable under the primary mountpoint at all.
+    fn pin(&self, rel: &Path, recorded: &Path) -> CoreResult<String> {
         let (ino, uid) = self.resolve(rel)?;
         let (name, is_folder, mtime, size) = {
             let st = self.state();
@@ -4245,34 +4316,105 @@ impl Core {
             )
         };
         if is_folder {
+            // Offline, every download would fail and the folder would only look
+            // kept. Refuse instead, as a file pin does.
+            if !self.is_online() {
+                return Err(CoreError::offline());
+            }
             // Record the recursive pin first so every descendant is eviction-
             // exempt before we start filling the cache with the subtree.
             self.cache
-                .add_pin(&uid, rel, true)
+                .add_pin(&uid, recorded, true)
                 .map_err(|e| CoreError::from_api(&e, "pin"))?;
-            let n = self.pin_subtree(ino)?;
-            return Ok(format!("{name} ({n} files)"));
+            let core = self.clone();
+            let folder = name.clone();
+            std::thread::Builder::new()
+                .name("pin-folder".into())
+                .spawn(move || core.pin_subtree(ino, &uid, &folder))
+                .map_err(|e| CoreError::internal(format!("spawn pin: {e}")))?;
+            return Ok(format!("{name}: downloading its files in the background"));
         }
-        let bytes = self
-            .download_file_tracked(&uid, &name, size)
-            .map_err(|e| CoreError::from_api(&e, "download"))?;
+        // Stored under a provisional size, the copy would never match the
+        // plaintext it holds (`docs/BUGS.md` B282).
+        let size = match self.kept_file(ino) {
+            Some(file) if file.uid == uid => file.size,
+            _ => size,
+        };
+        self.fetch_content(&uid, &name, mtime, size)?;
         self.cache
-            .store(&uid, mtime, size, &bytes)
-            .map_err(|e| CoreError::internal(format!("cache store: {e}")))?;
-        self.cache
-            .add_pin(&uid, rel, false)
+            .add_pin(&uid, recorded, false)
             .map_err(|e| CoreError::from_api(&e, "pin"))?;
         Ok(name)
     }
 
-    /// Download and cache every file in the subtree rooted at folder `ino`,
-    /// returning the count cached (already-fresh blobs counted, not re-fetched).
-    /// Walks the tree depth-first, enumerating each folder so a cold subtree is
-    /// fully discovered; the lock is dropped before each network download.
-    fn pin_subtree(&self, ino: u64) -> CoreResult<usize> {
-        let mut files: Vec<(NodeUid, String, i64, u64)> = Vec::new();
+    /// Download and cache every file in the subtree rooted at the pinned folder
+    /// `ino` (`folder`, named `name`), as a job the front ends show. Walks the
+    /// tree depth-first, enumerating each folder so a cold subtree is fully
+    /// discovered; the lock is dropped before each network download. Stops when
+    /// the folder is unpinned or the daemon stops.
+    fn pin_subtree(&self, ino: u64, folder: &NodeUid, name: &str) {
+        let job = self
+            .transfers
+            .begin_job(format!("Making {name} available offline"));
+        match self.pin_subtree_files(ino) {
+            Ok(files) => {
+                job.set_total(files.len() as u64);
+                let mut failed = 0usize;
+                for ino in files {
+                    if self.shutdown.is_stopping() || !self.cache.is_pinned(folder) {
+                        return;
+                    }
+                    // A file with a queued write, or no readable size, is
+                    // left to the drain and the keeper (`keeper::kept_file`).
+                    if let Some(file) = self.kept_file(ino) {
+                        job.detail(file.name.clone());
+                        if let Err(e) =
+                            self.fetch_pinned(&file.uid, &file.name, file.mtime, file.size)
+                        {
+                            warn!(uid = %file.uid, error = %e, "pin folder: download failed");
+                            failed += 1;
+                        }
+                    }
+                    job.step();
+                }
+                info!(folder = %name, failed, "pin folder: done");
+            }
+            Err(e) => warn!(folder = %name, error = %e, "pin folder: enumerate failed"),
+        }
+    }
+
+    /// Cache the file `uid` for a folder pin. Its `mtime` and `size` were read
+    /// before the download, and a create landing or a remote edit can change
+    /// them while it runs. The blob is then stored under the old ones and reads
+    /// as stale, so the file is listed as kept but not available offline. Fetch
+    /// it again under the new ones, a few times at most.
+    fn fetch_pinned(&self, uid: &NodeUid, name: &str, mtime: i64, size: u64) -> CoreResult<()> {
+        let mut fetched = (mtime, size);
+        for _ in 0..3 {
+            self.fetch_content(uid, name, fetched.0, fetched.1)?;
+            let current = {
+                let st = self.state();
+                st.by_uid
+                    .get(uid)
+                    .and_then(|ino| st.entries.get(ino))
+                    .map(|e| (e.node.modification_time, node_size(&e.node)))
+            };
+            match current {
+                Some(now) if now != fetched => fetched = now,
+                _ => break,
+            }
+        }
+        Ok(())
+    }
+
+    /// The inode of every file in the subtree rooted at folder `ino`.
+    fn pin_subtree_files(&self, ino: u64) -> CoreResult<Vec<u64>> {
+        let mut files: Vec<u64> = Vec::new();
         let mut stack = vec![ino];
         while let Some(dir) = stack.pop() {
+            if self.shutdown.is_stopping() {
+                break;
+            }
             self.ensure_children(dir)
                 .map_err(|e| self.errno_error(e, "enumerate"))?;
             let st = self.state();
@@ -4282,33 +4424,13 @@ impl Core {
                         if e.node.is_folder() {
                             stack.push(k);
                         } else {
-                            files.push((
-                                e.uid.clone(),
-                                e.node.name.clone(),
-                                e.node.modification_time,
-                                node_size(&e.node),
-                            ));
+                            files.push(k);
                         }
                     }
                 }
             }
         }
-        let mut count = 0;
-        for (uid, name, mtime, size) in files {
-            if self.cache.is_cached(&uid, mtime, size) {
-                count += 1;
-                continue;
-            }
-            match self.download_file_tracked(&uid, &name, size) {
-                Ok(bytes) => {
-                    if self.cache.store(&uid, mtime, size, &bytes).is_ok() {
-                        count += 1;
-                    }
-                }
-                Err(e) => warn!(%uid, error = %e, "pin subtree: download failed"),
-            }
-        }
-        Ok(count)
+        Ok(files)
     }
 
     /// Fetch a thumbnail of `ttype` for the file at `ino`, served from the cache
@@ -4332,9 +4454,15 @@ impl Core {
         if self.thumbnail_misses.lock().remote_contains(&key, mtime) {
             return Ok(None);
         }
+        // A file manager asks for one per file in a folder, on the metadata
+        // workers. Offline, or on a stalled link, each one held a worker for
+        // the SDK's whole retry budget, and every cold lookup, create and
+        // rename on the mount queued behind them (`docs/BUGS.md` B220).
+        if !self.is_online() {
+            return Ok(None);
+        }
         let bytes = self
-            .rt
-            .block_on(self.client.download_thumbnail(&uid, ttype))
+            .block_on_bounded(self.client.download_thumbnail(&uid, ttype))
             .map_err(|e| {
                 warn!(%uid, error = %e, "download thumbnail failed");
                 Errno::EIO
@@ -4354,6 +4482,8 @@ impl Core {
 
     /// Unpin the node at `rel`, evicting its cached content. For a folder, also
     /// evicts every descendant's cached blob (the subtree is no longer kept).
+    /// A node kept only because a folder above it is pinned is refused: there
+    /// is no pin of its own to remove, and it would stay kept all the same.
     fn unpin(&self, rel: &Path) -> CoreResult<String> {
         let (ino, uid) = self.resolve(rel)?;
         let (name, is_folder) = {
@@ -4363,14 +4493,24 @@ impl Core {
                 .map(|e| (e.node.name.clone(), e.node.is_folder()))
                 .unwrap_or_default()
         };
+        if self.pinned_by_folder(ino) {
+            return Err(CoreError::conflict(format!(
+                "{name} is kept offline because a folder above it is; unpin that folder instead"
+            )));
+        }
         self.cache
             .remove_pin(&uid)
             .map_err(|e| CoreError::from_api(&e, "unpin"))?;
         // A recursively-pinned folder's descendants were eviction-exempt; now
         // that the pin is gone, reclaim their blobs eagerly instead of waiting
-        // for budget pressure. Descendants come from the DB node tree.
+        // for budget pressure. Descendants come from the DB node tree. One
+        // pinned on its own, or under a pinned subfolder, is still kept.
         if is_folder && let Ok(uids) = self.db.descendants(&uid.to_string()) {
+            let still_pinned = self.pinned_set();
             for s in uids {
+                if still_pinned.contains(&s) {
+                    continue;
+                }
                 if let Some(u) = parse_uid(&s) {
                     self.cache.evict(&u);
                     self.evict_reader(&u);
@@ -4380,6 +4520,20 @@ impl Core {
         Ok(name)
     }
 
+    /// Whether the node at `ino` is kept offline because a folder above it is
+    /// pinned, whether or not it is also pinned on its own.
+    fn pinned_by_folder(&self, ino: u64) -> bool {
+        let parent = {
+            let st = self.state();
+            st.entries
+                .get(&ino)
+                .filter(|e| e.parent != ino)
+                .and_then(|e| st.entries.get(&e.parent))
+                .map(|p| p.uid.clone())
+        };
+        parent.is_some_and(|uid| self.cache.is_pinned(&uid))
+    }
+
     /// A Photos API handle sharing this Core's Drive client and session, so it
     /// reuses the daemon's single authenticated session rather than logging in
     /// again (Proton refresh tokens are single-use). Cheap — the Drive client
@@ -4392,10 +4546,13 @@ impl Core {
     /// the same lazy remote enumeration `readdir` uses, projected into
     /// serializable [`DirEntry`]s (with per-file pin state).
     fn list_dir(&self, rel: &Path) -> CoreResult<Vec<DirEntry>> {
-        let (ino, _uid) = self.resolve(rel)?;
+        let (ino, uid) = self.resolve(rel)?;
         self.ensure_children(ino)
             .map_err(|e| self.errno_error(e, "enumerate"))?;
         self.settle_listing_sizes(ino);
+        // Every entry shares this folder as its parent, so one lookup says
+        // whether they are all kept through it.
+        let pinned_by_folder = self.cache.is_pinned(&uid);
         // Snapshot the listing, then drop the lock before touching the on-disk
         // pin registry so a slow disk read doesn't block FUSE metadata ops.
         let rows: Vec<(String, bool, u64, i64, NodeUid, u64)> = {
@@ -4427,7 +4584,8 @@ impl Core {
                 is_dir,
                 size,
                 modified,
-                pinned: self.cache.is_pinned(&uid),
+                pinned: pinned_by_folder || self.cache.is_pinned(&uid),
+                pinned_by_folder,
                 cached: !is_dir && self.cache.is_cached(&uid, modified, size),
                 uid: uid.to_string(),
                 // Listing entries live in the requested dir; the caller derives
@@ -5094,6 +5252,133 @@ impl Core {
         Ok(name)
     }
 
+    /// Copy a file or folder into `new_parent_rel` on Proton Drive, which copies
+    /// the content there: nothing is downloaded or uploaded. Both paths are
+    /// mountpoint-relative. A name already taken in the folder gets the next
+    /// free ` (n)` suffix. Returns the copy's name.
+    ///
+    /// Drive copies what it holds, so the copy is refused offline and while the
+    /// mount still owes Drive part of it: a node or folder only queued locally,
+    /// a file with a queued upload or unsaved writes, or — for a folder, whose
+    /// queued changes could sit anywhere below it — any queued op at all.
+    fn copy_to(&self, rel: &Path, new_parent_rel: &Path) -> CoreResult<String> {
+        let (ino, uid) = self.resolve(rel)?;
+        let (pino, new_parent_uid) = self
+            .resolve_path(new_parent_rel)
+            .map_err(|e| self.errno_error(e, "resolve new parent"))?;
+        self.ensure_children(pino)
+            .map_err(|e| self.errno_error(e, "enumerate"))?;
+        self.require_uid_writable(&new_parent_uid)
+            .map_err(|error| self.errno_error(error, "copy access"))?;
+        let (name, is_folder, unsaved) = {
+            let st = self.state();
+            let entry = st
+                .entries
+                .get(&ino)
+                .ok_or_else(|| CoreError::not_found(format!("{} is gone", rel.display())))?;
+            // Unsaved writes, or a release still queueing them, to the file or,
+            // for a folder, to any file below it.
+            let unsaved = st
+                .active_writes
+                .iter()
+                .filter(|(_, w)| w.dirty)
+                .map(|(&open, _)| open)
+                .chain(st.releasing.iter().copied())
+                .any(|open| relocate::ino_is_under(&st, open, ino));
+            (entry.node.name.clone(), entry.node.is_folder(), unsaved)
+        };
+        // Unlike a move, a copy cannot wait in the queue: it needs the node as
+        // Drive has it, so it goes now or not at all, local-first or not.
+        if !self.is_online() {
+            return Err(CoreError::offline());
+        }
+        let owed = unsaved
+            || is_local_uid(&uid)
+            || is_local_uid(&new_parent_uid)
+            || self.db.has_any_op(&uid.to_string()).unwrap_or(true)
+            || (is_folder
+                && self
+                    .db
+                    .pending_op_counts()
+                    .map(|counts| counts.uploads + counts.changes > 0)
+                    .unwrap_or(true));
+        if owed {
+            return Err(CoreError::conflict(format!(
+                "{name} has changes that have not reached Proton Drive yet; \
+                 copy it once they have synced"
+            )));
+        }
+        let target = if is_folder {
+            AvailableNameTarget::Folder
+        } else {
+            AvailableNameTarget::File
+        };
+        let copy_name = self
+            .rt
+            .block_on(
+                self.drive
+                    .get_available_name(&new_parent_uid, &name, target),
+            )
+            .map_err(|e| CoreError::from_api(&e, "copy"))?;
+        let new_uid = self
+            .rt
+            .block_on(
+                self.drive
+                    .copy_node(&uid, &new_parent_uid, Some(&copy_name)),
+            )
+            .map_err(|e| CoreError::from_api(&e, "copy"))?;
+        let node = self
+            .fetch_minted_node(&new_uid, &copy_name)
+            .ok_or_else(|| minted_but_unlisted(&copy_name))?;
+        let mut st = self.state();
+        let copy_ino = st.intern(pino, node);
+        if let Some(kids) = st.children.get_mut(&pino)
+            && !kids.contains(&copy_ino)
+        {
+            kids.push(copy_ino);
+        }
+        drop(st);
+        self.flush_access_changes();
+        Ok(copy_name)
+    }
+
+    /// What the folder at `rel` holds on Proton Drive: bytes on storage and the
+    /// number of items below it. Drive adds it up, so nothing is listed here;
+    /// trashed items count, and the bytes are encrypted ones.
+    pub(crate) fn folder_size(&self, rel: &Path) -> CoreResult<proton_drive_rs::FolderSize> {
+        let (ino, uid) = self.resolve(rel)?;
+        let is_folder = self
+            .state()
+            .entries
+            .get(&ino)
+            .is_some_and(|entry| entry.node.is_folder());
+        if !is_folder {
+            return Err(CoreError::invalid(format!(
+                "{} is not a folder",
+                rel.display()
+            )));
+        }
+        self.folder_size_for_uid(&uid)
+    }
+
+    /// [`Core::folder_size`] for a folder addressed through any daemon location.
+    pub(crate) fn folder_size_by_uid(&self, uid: &str) -> CoreResult<proton_drive_rs::FolderSize> {
+        let uid = self.resolve_anywhere(uid)?;
+        self.folder_size_for_uid(&uid)
+    }
+
+    fn folder_size_for_uid(&self, uid: &NodeUid) -> CoreResult<proton_drive_rs::FolderSize> {
+        if is_local_uid(uid) {
+            return Err(CoreError::conflict("the folder is not on Proton Drive yet"));
+        }
+        if !self.is_online() {
+            return Err(CoreError::offline());
+        }
+        self.rt
+            .block_on(self.client.get_folder_size(uid))
+            .map_err(|e| CoreError::from_api(&e, "folder size"))
+    }
+
     /// Trash a file or folder. `rel` is mountpoint-relative. Forgets the node,
     /// evicts any cached content, and invalidates the parent listing.
     fn delete(&self, rel: &Path) -> CoreResult<String> {
@@ -5142,9 +5427,12 @@ impl Core {
     /// `unlink` under an open handle. Its queued ops go now, or the drain would
     /// upload to the node after it was trashed (`docs/BUGS.md` B106).
     fn remove_replaced(&self, ino: u64, uid: &NodeUid, name: &str) -> Result<(), Errno> {
+        // Asked under the uid the tree has now: a landed create's real uid is
+        // not in the tree yet (`docs/BUGS.md` B257).
+        let open = self.is_open_anywhere(uid);
         let landed;
         let uid = if is_local_uid(uid) {
-            if self.is_open_anywhere(uid) {
+            if open {
                 self.withdraw_queued_ops(uid)?;
             } else {
                 self.discard_queued_ops(uid)?;
@@ -5169,7 +5457,7 @@ impl Core {
         // Local-first or offline, or the network goes away under the call:
         // queue the trash. The rename that follows queues as well, behind it.
         if !self.sends_inline() {
-            return self.queue_trash(uid, name);
+            return self.queue_trash(uid, name, open);
         }
         self.require_uid_writable(uid)?;
         if let Err(e) = self
@@ -5177,7 +5465,7 @@ impl Core {
             .and_then(batch::into_unit)
         {
             if self.lost_link(&e, "trash a replaced node") {
-                return self.queue_trash(uid, name);
+                return self.queue_trash(uid, name, open);
             }
             error!(%uid, name, error = %e, "trashing the node a rename replaces failed");
             self.log_activity(ActivityKind::Trash, name, e.to_string(), false);
@@ -5319,6 +5607,7 @@ impl Core {
                 // A trashed node can't be pinned or served from the mount, so its
                 // content is never current cache: report neither.
                 pinned: false,
+                pinned_by_folder: false,
                 cached: false,
                 uid: item.uid,
                 path: String::new(),
@@ -5749,6 +6038,7 @@ impl Core {
         if let Some(p) = self.sync_progress.lock().get_mut(&folder_id) {
             f(p);
         }
+        self.sync_engine.moved();
     }
 
     /// Set the number of items the scan expects to check, from the size of the
@@ -6052,11 +6342,61 @@ fn is_gone(e: &(dyn std::error::Error + 'static)) -> bool {
 /// (`sync.rs`, `conflict_path`), so the two halves of the product name the same
 /// situation the same way and a user only has to learn it once.
 fn conflict_name(name: &str, stamp: i64) -> String {
+    conflict_name_as(name, conflict_label(), stamp)
+}
+
+/// [`conflict_name`] with the machine's label given.
+fn conflict_name_as(name: &str, label: &str, stamp: i64) -> String {
     let path = Path::new(name);
     let stem = path.file_stem().and_then(|s| s.to_str()).unwrap_or(name);
+    let tag = conflict_tag(label, stamp, 0);
     match path.extension().and_then(|s| s.to_str()) {
-        Some(ext) => format!("{stem} (sync-conflict {stamp}).{ext}"),
-        None => format!("{stem} (sync-conflict {stamp})"),
+        Some(ext) => format!("{stem} (sync-conflict {tag}).{ext}"),
+        None => format!("{stem} (sync-conflict {tag})"),
+    }
+}
+
+/// This machine's name as its conflict copies carry it (`docs/BUGS.md` B251).
+///
+/// Two computers syncing one folder that each keep a copy of the same file in
+/// the same second would otherwise make the same name on Drive, and nobody
+/// could tell which computer a copy came from. Read once, from the hostname.
+fn conflict_label() -> &'static str {
+    static LABEL: OnceLock<String> = OnceLock::new();
+    LABEL.get_or_init(|| conflict_label_of(&this_hostname()))
+}
+
+/// `host` as one token: anything but ASCII letters, digits, `-`, `_` and `.`
+/// becomes `-`, so the label holds no space for `conflict_base_name` to trip
+/// on and no `/` or `)` to break the name.
+fn conflict_label_of(host: &str) -> String {
+    let label: String = host
+        .chars()
+        .take(32)
+        .map(|c| {
+            if c.is_ascii_alphanumeric() || matches!(c, '-' | '_' | '.') {
+                c
+            } else {
+                '-'
+            }
+        })
+        .collect();
+    label.trim_matches('-').to_string()
+}
+
+/// The inside of a conflict copy's marker: `<label> <stamp>`, with `-<n>`
+/// when an earlier copy already holds that name. Without a label it is the
+/// bare stamp that copies had before B251.
+fn conflict_tag(label: &str, stamp: i64, suffix: u32) -> String {
+    let suffix = if suffix == 0 {
+        String::new()
+    } else {
+        format!("-{suffix}")
+    };
+    if label.is_empty() {
+        format!("{stamp}{suffix}")
+    } else {
+        format!("{label} {stamp}{suffix}")
     }
 }
 
@@ -6140,6 +6480,7 @@ fn sync_folder_info(
 ) -> SyncFolderInfo {
     SyncFolderInfo {
         id: f.id,
+        kind: f.kind,
         local_path: f.local_path,
         remote_uid: f.remote_uid,
         mode: f.mode,
@@ -6666,7 +7007,27 @@ fn fuse_name(name: &OsStr) -> Result<String, Errno> {
     name.to_str().map(str::to_owned).ok_or(Errno::EILSEQ)
 }
 
+/// Whether a decrypted remote name can stand as one local path component.
+///
+/// Drive checks names only when a client creates or renames a node, and only
+/// for length, so a name made by another client, or by a server that should
+/// not be trusted, can hold anything. Joined onto a local path, a `/` or a `..`
+/// in it walks out of the folder it belongs to, and the mirror engine would
+/// then write or delete outside the sync root. In the mount, the kernel fails
+/// the whole listing with EIO on a single such name (`docs/BUGS.md` B215).
+pub(crate) fn remote_name_is_safe(name: &str) -> bool {
+    !name.is_empty()
+        && name != "."
+        && name != ".."
+        && name.len() <= 255
+        && !name.contains(['/', '\0'])
+}
+
 fn node_visible(node: &Node, folder_uid: &NodeUid, hidden: &HashSet<NodeUid>) -> bool {
+    if !remote_name_is_safe(&node.name) {
+        warn!(uid = %node.uid, "a remote name cannot be a local file name; leaving it out");
+        return false;
+    }
     !node.trashed && node.uid != *folder_uid && !hidden.contains(&node.uid)
 }
 
@@ -7002,13 +7363,15 @@ mod size_upgrade_tests {
     fn a_listing_waits_for_the_whole_size_batch_but_not_forever() {
         let slot = Arc::new(SizeUpgrade::default());
         let worker = slot.clone();
+        // Read before the spawn: the worker's sleeps can start before this
+        // thread runs again, which made the bound below fail on a busy runner.
+        let started = Instant::now();
         let t = std::thread::spawn(move || {
             std::thread::sleep(Duration::from_millis(30));
             worker.chunk_done();
             std::thread::sleep(Duration::from_millis(60));
             worker.finish();
         });
-        let started = Instant::now();
         slot.wait_finished(started + Duration::from_secs(5));
         // Past the first chunk, up to the end of the batch.
         assert!(started.elapsed() >= Duration::from_millis(90));
@@ -7415,14 +7778,15 @@ mod tests {
     use super::{
         Access, AccessFlags, Errno, HashMap, Intervals, PendingRevision, RootListingSnapshot,
         SELF_CHANGE_TTL_MS, ShareId, SharedWithMeItem, StateRegistry, VirtualRootPlan,
-        accepted_share_provenance, conflict_name, copy_pending_for_truncate, expand_restore,
-        first_seen_in_trash, fuse_name, is_stale_mount, node_visible, note_self_change,
-        off_the_runtime, orphan_past_retention, parse_node_uid, prepare_shared_roots,
-        preserve_on_access_denied, publish_virtual_root_in_listing,
-        reconcile_virtual_root_in_listing, release_can_discard_unlinked,
-        release_must_retain_queued_trash, release_unlinked_entry, rename_needs_queue,
-        require_node_parent_access, require_rename_access, resolve_anywhere_with,
-        shared_with_me_uid, take_self_change, uid_write_authority, virtual_node,
+        accepted_share_provenance, conflict_label, conflict_label_of, conflict_name,
+        conflict_name_as, copy_pending_for_truncate, expand_restore, first_seen_in_trash,
+        fuse_name, is_stale_mount, node_visible, note_self_change, off_the_runtime,
+        orphan_past_retention, parse_node_uid, prepare_shared_roots, preserve_on_access_denied,
+        publish_virtual_root_in_listing, reconcile_virtual_root_in_listing,
+        release_can_discard_unlinked, release_must_retain_queued_trash, release_unlinked_entry,
+        rename_needs_queue, require_node_parent_access, require_rename_access,
+        resolve_anywhere_with, shared_with_me_uid, take_self_change, uid_write_authority,
+        virtual_node,
     };
     use super::{Db, WriteAuthority};
     use std::time::Duration;
@@ -8377,15 +8741,38 @@ mod tests {
     #[test]
     fn conflict_name_keeps_the_extension() {
         assert_eq!(
-            conflict_name("notes.txt", 1700),
-            "notes (sync-conflict 1700).txt"
+            conflict_name_as("notes.txt", "laptop", 1700),
+            "notes (sync-conflict laptop 1700).txt"
         );
-        assert_eq!(conflict_name("README", 42), "README (sync-conflict 42)");
         assert_eq!(
-            conflict_name("archive.tar.gz", 7),
-            "archive.tar (sync-conflict 7).gz",
+            conflict_name_as("README", "laptop", 42),
+            "README (sync-conflict laptop 42)"
+        );
+        assert_eq!(
+            conflict_name_as("archive.tar.gz", "laptop", 7),
+            "archive.tar (sync-conflict laptop 7).gz",
             "only the last extension is one, as everywhere else"
         );
+        assert_eq!(
+            conflict_name_as("notes.txt", "", 1700),
+            "notes (sync-conflict 1700).txt"
+        );
+        assert_eq!(
+            conflict_name("notes.txt", 1700),
+            conflict_name_as("notes.txt", conflict_label(), 1700)
+        );
+    }
+
+    /// A hostname goes into a file name, so it is cut down to one safe token
+    /// (B251).
+    #[test]
+    fn a_hostname_becomes_one_safe_token() {
+        assert_eq!(conflict_label_of("laptop"), "laptop");
+        assert_eq!(conflict_label_of("my-pc.local"), "my-pc.local");
+        assert_eq!(conflict_label_of("Linux device"), "Linux-device");
+        assert_eq!(conflict_label_of("a/b) c"), "a-b--c");
+        assert_eq!(conflict_label_of("  "), "");
+        assert_eq!(conflict_label_of(&"x".repeat(40)).len(), 32);
     }
 
     #[test]
@@ -8577,6 +8964,28 @@ mod tests {
         ));
     }
 
+    #[test]
+    fn a_remote_name_that_is_not_one_path_component_is_left_out() {
+        let folder_uid = NodeUid::new(VolumeId::from("vol"), LinkId::from("folder"));
+        let none = std::collections::HashSet::new();
+        for name in [
+            "a/b",
+            "../../.bashrc",
+            "..",
+            ".",
+            "",
+            "a\0b",
+            &"x".repeat(256),
+        ] {
+            let node = node_helper("child", "folder", name, false);
+            assert!(!node_visible(&node, &folder_uid, &none), "{name:?}");
+        }
+        for name in [".hidden", "a..b", "unicodé-文件", &"x".repeat(255)] {
+            let node = node_helper("child", "folder", name, false);
+            assert!(node_visible(&node, &folder_uid, &none), "{name:?}");
+        }
+    }
+
     #[test]
     fn denied_queue_guard_preserves_accepted_bytes_and_pending_count() {
         use std::cell::Cell;
@@ -8897,7 +9306,7 @@ mod tests {
         assert!(!replaced.contains("st.forget(uid)"));
         assert_before(
             replaced,
-            "if self.is_open_anywhere(uid)",
+            "let open = self.is_open_anywhere(uid)",
             "self.discard_queued_ops(uid)",
         );
         assert_before(replaced, "if open_now", "self.cache.evict(uid)");
@@ -9082,6 +9491,32 @@ mod tests {
         assert!(online.contains("self.relist_offline_listings();"));
     }
 
+    #[test]
+    fn a_stale_shared_listing_is_fetched_off_the_dispatch_loop() {
+        // A resident listing that `list_children` would fetch again anyway
+        // must not be answered inline (B219).
+        let cached = function_source(include_str!("lib.rs"), "fn children_cached(");
+        assert!(cached.contains("SHARED_WITH_ME_SYNCED_MS"));
+        assert!(cached.contains("Self::shared_folder_freshness_key(&uid)"));
+        assert!(cached.contains("listing_needs_refresh("));
+        assert!(cached.contains("self.shared_listing_stale(&key)"));
+    }
+
+    #[test]
+    fn a_handler_does_not_wait_out_the_sdk_retry_budget() {
+        // Thumbnails, size upgrades and the share list held mount threads for
+        // minutes on a stalled link (B220).
+        let lib = include_str!("lib.rs");
+        let thumbnail = function_source(lib, "fn thumbnail(");
+        assert_before(thumbnail, "if !self.is_online()", "download_thumbnail");
+        assert!(thumbnail.contains(".block_on_bounded(self.client.download_thumbnail("));
+        let upgrade = function_source(lib, "fn run_size_upgrade(");
+        assert!(upgrade.contains("block_on_within(BATCH_CALL_TIMEOUT"));
+        let shared = function_source(lib, "fn ensure_shared_children(");
+        assert!(shared.contains("block_on_within(BATCH_CALL_TIMEOUT"));
+        assert!(!shared.contains("self.rt"));
+    }
+
     #[test]
     fn a_remote_read_gives_up_at_its_deadline() {
         // The SDK bounds requests, not reads; a stalled link held one `read`

crates/pdfs-fuse/src/link.rs

@@ -29,6 +29,13 @@ use crate::{Core, ONLINE_PROBE_MAX, ONLINE_PROBE_MIN};
 /// keep waiting for; queueing the change is the better answer.
 pub(crate) const INTERACTIVE_CALL_TIMEOUT: Duration = Duration::from_secs(20);
 
+/// How long a mount thread waits on a remote read that answers a batch: a
+/// chunk of file sizes, or the list of shares. Longer than an interactive call,
+/// since its answer grows with the batch, but well short of the SDK's own retry
+/// budget, which held a worker for minutes on a stalled link
+/// (`docs/BUGS.md` B220).
+pub(crate) const BATCH_CALL_TIMEOUT: Duration = Duration::from_secs(60);
+
 /// How long one probe may wait for an answer. A probe is a single small request,
 /// and a probe stuck in the SDK's retry budget would delay noticing the link is
 /// back by as long as it waits.
@@ -112,10 +119,25 @@ pub(crate) fn no_answer(after: Duration) -> ProtonError {
 /// transfer that has stopped moving runs into it.
 const SLOWEST_UPLOAD: u64 = 32 * 1024;
 
+/// How many uploads can share the upload cap at once: one per drain worker
+/// and one per mirror sync task.
+const UPLOAD_SLOTS: u64 = (crate::DRAIN_WORKERS + crate::sync::SYNC_CONCURRENCY) as u64;
+
 /// How long an upload of `len` bytes may take before the link is treated as
 /// down: the budget of a metadata call, plus the bytes at [`SLOWEST_UPLOAD`].
-pub(crate) fn upload_deadline(len: u64) -> Duration {
-    INTERACTIVE_CALL_TIMEOUT + Duration::from_secs(len / SLOWEST_UPLOAD)
+///
+/// An upload cap of `cap` bytes per second (`0` for none) is shared by every
+/// upload running, so each may get as little as its share of it. Below
+/// [`SLOWEST_UPLOAD`] a share counts as the slowest rate instead: measured
+/// against the fixed rate, a large file under a low cap ran out of time on
+/// every attempt, took the mount offline each time, and started over from
+/// its first byte.
+pub(crate) fn upload_deadline(len: u64, cap: u64) -> Duration {
+    let slowest = match cap {
+        0 => SLOWEST_UPLOAD,
+        cap => SLOWEST_UPLOAD.min((cap / UPLOAD_SLOTS).max(1)),
+    };
+    INTERACTIVE_CALL_TIMEOUT + Duration::from_secs(len / slowest)
 }
 
 /// Run a remote call, giving up after [`INTERACTIVE_CALL_TIMEOUT`].
@@ -258,11 +280,15 @@ impl Core {
         self.relist_offline_listings();
         // Anything written while offline is queued and waiting on exactly this,
         // including ops that failed on the way down and are sitting out a
-        // backoff sized for a server that keeps refusing.
-        if let Err(e) = self.db.retry_failed_ops_now(crate::now_millis()) {
+        // backoff sized for a server that keeps refusing. Ops Drive refused
+        // keep theirs: the link was not why.
+        if let Err(e) = self.db.retry_unrefused_ops_now(crate::now_millis()) {
             warn!(error = %e, "moving backed-off ops up after a reconnect failed");
         }
         self.wake_drain();
+        // Downloads for pins failed while the link was down, and the events
+        // that would have named the files are behind us (`docs/BUGS.md` B282).
+        self.recheck_all_pins();
     }
 
     /// Wait up to `budget` for the link to come back. Returns whether it is up.
@@ -403,13 +429,31 @@ mod tests {
 
     #[test]
     fn an_upload_gets_longer_the_bigger_it_is() {
-        assert_eq!(upload_deadline(0), INTERACTIVE_CALL_TIMEOUT);
+        assert_eq!(upload_deadline(0, 0), INTERACTIVE_CALL_TIMEOUT);
         assert_eq!(
-            upload_deadline(1 << 30),
+            upload_deadline(1 << 30, 0),
             INTERACTIVE_CALL_TIMEOUT + Duration::from_secs(32_768)
         );
     }
 
+    #[test]
+    fn an_upload_under_a_low_cap_gets_the_time_its_share_of_the_cap_needs() {
+        // A generous cap leaves the deadline as it was.
+        assert_eq!(
+            upload_deadline(1 << 30, 100 << 20),
+            upload_deadline(1 << 30, 0)
+        );
+        // 512 KiB/s shared by every upload slot is below the slowest rate.
+        let share = (512 << 10) / UPLOAD_SLOTS;
+        assert!(share < SLOWEST_UPLOAD);
+        assert_eq!(
+            upload_deadline(1 << 30, 512 << 10),
+            INTERACTIVE_CALL_TIMEOUT + Duration::from_secs((1 << 30) / share)
+        );
+        // A cap below one byte per slot still gives a finite deadline.
+        assert!(upload_deadline(1 << 20, 1) > upload_deadline(1 << 20, 512 << 10));
+    }
+
     #[test]
     fn a_call_past_its_deadline_reads_as_a_lost_link() {
         let rt = tokio::runtime::Builder::new_current_thread()

crates/pdfs-fuse/src/mount.rs

@@ -196,6 +196,43 @@ pub(super) fn clear_stale_mount(mountpoint: &Path) {
     }
 }
 
+/// Make sure `mountpoint` is a directory a mount can go on, clearing a dead
+/// mount a killed daemon left there first.
+///
+/// A dead mount answers `ENOTCONN`, which `create_dir_all` takes for "absent";
+/// it then tries `mkdir` and fails with `EEXIST`. The daemon retried that error
+/// forever and never got as far as [`check_mountpoint`], which would have
+/// cleared the mount (`docs/BUGS.md` B279).
+pub fn prepare_mountpoint(mountpoint: &Path) -> std::io::Result<()> {
+    if is_stale_mount(mountpoint) {
+        clear_stale_mount(mountpoint);
+    }
+    std::fs::create_dir_all(mountpoint)
+}
+
+/// Refuse to mount My files over a folder that already has files in it: FUSE
+/// would hide them, unsent and out of sight, until the service stops
+/// (`docs/BUGS.md` B277). Runs before the root fetch and before any worker
+/// starts, so a refusal costs nothing to retry.
+///
+/// A dead mount is cleared first, since it cannot be listed. One of this
+/// client's own live mounts is left to [`spawn_session`], which clears it as it
+/// always has; listing it would show Drive's files, not the folder's.
+pub(super) fn check_mountpoint(mountpoint: &Path) -> std::io::Result<()> {
+    if is_stale_mount(mountpoint) {
+        clear_stale_mount(mountpoint);
+    }
+    if pdfs_core::mountpoint::mounted_fs_type(mountpoint).as_deref()
+        == Some(pdfs_core::mountpoint::OWN_FS_TYPE)
+    {
+        return Ok(());
+    }
+    match pdfs_core::mountpoint::not_empty(mountpoint)? {
+        Some(found) => Err(std::io::Error::other(found)),
+        None => Ok(()),
+    }
+}
+
 /// `sync_state` key holding the uid of the My Files root, so a later run can
 /// recover it from `nodes` without the API.
 const ROOT_UID_KEY: &str = "root_uid";
@@ -427,6 +464,7 @@ pub(crate) fn mount_with(
     // Start the uptime clock here rather than at the first `pdfs diagnostics`,
     // so the age it reports is the daemon's own.
     super::diagnostics::start_clock();
+    check_mountpoint(mountpoint)?;
     let (root, start) = fetch_or_recall_root(drive.as_ref(), &rt, &db)?;
     let online = start == Start::Online;
     let scope = root.tree_event_scope_id();
@@ -473,6 +511,7 @@ pub(crate) fn mount_with(
         landed: Arc::new(Mutex::new(HashMap::new())),
         unadopted: Arc::new(Mutex::new(HashMap::new())),
         drain_wake: Arc::new((Mutex::new(false), Condvar::new())),
+        pin_work: Arc::new(Mutex::new(Default::default())),
         shutdown: Arc::new(crate::shutdown::Shutdown::default()),
         upload_times: Arc::new(Mutex::new(HashMap::new())),
         upload_cancel: Arc::new(Mutex::new(HashMap::new())),
@@ -507,6 +546,7 @@ pub(crate) fn mount_with(
         events: Arc::new(Default::default()),
         indexing: Arc::new(AtomicBool::new(false)),
         sync_progress: Arc::new(Mutex::new(HashMap::new())),
+        sync_engine: Arc::default(),
         sync_tx,
         mounts: Arc::new(Mutex::new(SecondaryMountRegistry::default())),
         sync_locks: Arc::new(Mutex::new(HashMap::new())),
@@ -540,12 +580,11 @@ pub(crate) fn mount_with(
     // and sweeps all operating on a mount that no longer exists (`docs/BUGS.md` B44).
     let mut workers: Vec<std::thread::JoinHandle<()>> = Vec::new();
     for worker in 0..DRAIN_WORKERS {
-        let core = core.clone();
-        workers.push(
-            std::thread::Builder::new()
-                .name(format!("pdfs-drain-{worker}"))
-                .spawn(move || core.run_pending_drain(worker == 0))?,
-        );
+        let drain_core = core.clone();
+        let spawned = std::thread::Builder::new()
+            .name(format!("pdfs-drain-{worker}"))
+            .spawn(move || drain_core.run_pending_drain(worker == 0));
+        keep_or_abandon(&core, control_socket, &mut workers, spawned)?;
     }
 
     // Start the folder-sync engine. It watches every mirror folder, polls the
@@ -565,24 +604,33 @@ pub(crate) fn mount_with(
         info!("conflict sweep disabled by configuration");
     } else {
         info!(mode = ?sweep_mode, "conflict sweep enabled");
-        let core = core.clone();
-        workers.push(
-            std::thread::Builder::new()
-                .name("pdfs-conflict-sweep".into())
-                .spawn(move || core.run_conflict_sweep_loop())?,
-        );
+        let sweep_core = core.clone();
+        let spawned = std::thread::Builder::new()
+            .name("pdfs-conflict-sweep".into())
+            .spawn(move || sweep_core.run_conflict_sweep_loop());
+        keep_or_abandon(&core, control_socket, &mut workers, spawned)?;
     }
 
     // Watch the link for the life of the mount: a mount from the cache waits for
     // the network to come back, and an online one can lose it at any moment and
     // must notice it coming back just the same.
     {
-        let core = core.clone();
-        workers.push(
-            std::thread::Builder::new()
-                .name("pdfs-online-probe".into())
-                .spawn(move || core.run_online_probe())?,
-        );
+        let probe_core = core.clone();
+        let spawned = std::thread::Builder::new()
+            .name("pdfs-online-probe".into())
+            .spawn(move || probe_core.run_online_probe());
+        keep_or_abandon(&core, control_socket, &mut workers, spawned)?;
+    }
+
+    // Keep pinned files on this computer through changes made elsewhere, and
+    // fetch the ones a failed or missed download left out (`docs/BUGS.md`
+    // B282). Its own thread: a check lists folders and downloads files.
+    {
+        let keeper_core = core.clone();
+        let spawned = std::thread::Builder::new()
+            .name("pdfs-pin-keeper".into())
+            .spawn(move || keeper_core.run_pin_keeper());
+        keep_or_abandon(&core, control_socket, &mut workers, spawned)?;
     }
 
     // Keep the launcher prompt's "This computer" index fresh. Its own thread:
@@ -593,11 +641,10 @@ pub(crate) fn mount_with(
         let transfers = core.transfers.clone();
         let mountpoint = mountpoint.to_path_buf();
         let shutdown = core.shutdown.clone();
-        workers.push(
-            std::thread::Builder::new()
-                .name("pdfs-localindex".into())
-                .spawn(move || run_local_index(db, indexing, transfers, mountpoint, shutdown))?,
-        );
+        let spawned = std::thread::Builder::new()
+            .name("pdfs-localindex".into())
+            .spawn(move || run_local_index(db, indexing, transfers, mountpoint, shutdown));
+        keep_or_abandon(&core, control_socket, &mut workers, spawned)?;
     }
 
     // Bind the control socket before the FUSE session takes over the thread. A
@@ -606,12 +653,18 @@ pub(crate) fn mount_with(
     let old_umask = unsafe { libc::umask(0o77) };
     let listener_res = UnixListener::bind(control_socket);
     unsafe { libc::umask(old_umask) };
-    let listener = listener_res?;
+    let listener = match listener_res {
+        Ok(listener) => listener,
+        Err(error) => {
+            abandon_workers(&core, control_socket, workers);
+            return Err(error);
+        }
+    };
     // Owner-only before anything can connect: a peer on this socket commands the
     // daemon's authenticated session without a credential of its own (B6).
     if let Err(e) = pdfs_core::config::restrict_socket(control_socket) {
         error!(error = %e, "cannot restrict control socket permissions; refusing to serve");
-        let _ = std::fs::remove_file(control_socket);
+        abandon_workers(&core, control_socket, workers);
         return Err(std::io::Error::other(format!(
             "control socket permissions: {e}"
         )));
@@ -622,7 +675,7 @@ pub(crate) fn mount_with(
     let bg = match spawn_session(&core, mountpoint, root) {
         Ok(session) => session,
         Err(error) => {
-            let _ = std::fs::remove_file(control_socket);
+            abandon_workers(&core, control_socket, workers);
             return Err(error);
         }
     };
@@ -642,7 +695,7 @@ pub(crate) fn mount_with(
             Err(error) => {
                 // A failure here abandons the mount, so the background threads
                 // started above have to be told to stop with it.
-                stop_workers(&core, control_socket, workers);
+                abandon_workers(&core, control_socket, workers);
                 let secondaries = core.mounts.lock().close_and_drain();
                 for (id, mount) in secondaries {
                     if let Err(unmount_error) = mount.teardown() {
@@ -692,8 +745,12 @@ pub(crate) fn mount_with(
         }
     }
     // The mount is live and the control socket answers: this is the moment the
-    // unit is actually usable, which is what `Type=notify` reports.
+    // unit is actually usable, which is what `Type=notify` reports. Whatever
+    // failure an earlier attempt recorded for the front ends is over.
     systemd::ready();
+    if let Some(state_dir) = control_socket.parent() {
+        pdfs_core::mountfail::clear(state_dir);
+    }
 
     // Re-establish on-demand mounts only after the primary session is live.
     // Keep the worker so shutdown can close publication, wait for any in-flight
@@ -859,6 +916,43 @@ fn stop_workers(core: &Core, control_socket: &Path, workers: Vec<std::thread::Jo
     // Say so before the joins: a teardown that takes a while must not be read as
     // a missed watchdog ping and turned into a kill.
     systemd::stopping();
+    halt_workers(core, control_socket, workers);
+}
+
+/// Stop the threads a mount attempt started before it failed.
+///
+/// The early returns used to leave them running: every retry started another
+/// set beside the last one's, and their `Core` kept the database open, so the
+/// next attempt could fail on its lock instead of the real error
+/// (`docs/BUGS.md` B264). Unlike [`stop_workers`] this does not tell systemd
+/// the daemon is stopping, because it is about to try again, and a manager
+/// told so would wait for the process to exit and then kill it.
+fn abandon_workers(core: &Core, control_socket: &Path, workers: Vec<std::thread::JoinHandle<()>>) {
+    halt_workers(core, control_socket, workers);
+}
+
+/// Keep a worker the mount just spawned, or, if the spawn failed, stop the
+/// ones already running and hand the error back.
+fn keep_or_abandon(
+    core: &Core,
+    control_socket: &Path,
+    workers: &mut Vec<std::thread::JoinHandle<()>>,
+    spawned: std::io::Result<std::thread::JoinHandle<()>>,
+) -> std::io::Result<()> {
+    match spawned {
+        Ok(handle) => {
+            workers.push(handle);
+            Ok(())
+        }
+        Err(error) => {
+            abandon_workers(core, control_socket, std::mem::take(workers));
+            Err(error)
+        }
+    }
+}
+
+/// Signal every worker to stop, then join them up to [`WORKER_JOIN_DEADLINE`].
+fn halt_workers(core: &Core, control_socket: &Path, workers: Vec<std::thread::JoinHandle<()>>) {
     core.shutdown.stop();
     core.wake_drain();
     let _ = core.sync_tx.send(sync::SyncMsg::Stop);

crates/pdfs-fuse/src/photos.rs

@@ -9,7 +9,7 @@ use std::collections::{HashMap, HashSet};
 use std::ffi::OsStr;
 use std::fs::OpenOptions;
 use std::io::{Read as _, Write as _};
-use std::os::unix::fs::OpenOptionsExt as _;
+use std::os::unix::fs::{FileExt as _, OpenOptionsExt as _};
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 use std::sync::atomic::{AtomicU64, Ordering};
@@ -20,14 +20,17 @@ use base64::Engine as _;
 use pdfs_core::control::{
     FileThumbRequest, MappingProgress, PhotoItem, PhotoKind, PhotoLocation, PhotoThumb, PlaceInfo,
     ThumbnailBuildStatus, Topic, is_raw_image_name, is_thumbnail_image_name,
+    is_thumbnail_media_name,
 };
 use pdfs_core::db::{self, StoredPhoto};
 use pdfs_core::{CoreError, CoreResult};
 
+use proton_drive_rs::proton_sdk::error::Result as DriveResult;
 use proton_drive_rs::proton_sdk::ids::NodeUid;
 use proton_drive_rs::{NodeKind, PhotoTag, PhotoTagsUpdate, Thumbnail, ThumbnailType};
 use tracing::{debug, info, warn};
 
+use super::drive::RevisionRead;
 use super::{
     Core, PHOTOS_AVAILABLE, PHOTOS_SYNCED_MS, TIMELINE_ENRICH_CHUNK, TIMELINE_TTL, WriteAuthority,
     node_size, now_ms, parse_uid,
@@ -58,9 +61,18 @@ const EXIFTOOL_TIMEOUT: Duration = Duration::from_secs(20);
 static RAW_TEMP_NONCE: AtomicU64 = AtomicU64::new(0);
 static EXIFTOOL_MISSING_WARNING: Once = Once::new();
 static FFMPEG_MISSING_WARNING: Once = Once::new();
-/// Largest video downloaded whole to grab one frame for its thumbnail. The
-/// download lands in memory, so a long 4K recording is left without one.
-const VIDEO_THUMB_MAX_BYTES: u64 = 256 * 1024 * 1024;
+/// How much of a video's start a thumbnail downloads. The first frame, and
+/// the one a second in, sit inside it at any common bitrate. A video is never
+/// downloaded whole for one frame: a recording can be many gigabytes.
+const VIDEO_HEAD_BYTES: u64 = 16 * 1024 * 1024;
+/// A video no larger than this is downloaded whole: its head and tail would
+/// cover most of it anyway.
+const VIDEO_WHOLE_MAX_BYTES: u64 = 24 * 1024 * 1024;
+/// Largest MP4/MOV index (`moov` box) fetched from past the head. An hour of
+/// video indexes in a few MiB; anything larger is not worth one frame.
+const VIDEO_INDEX_MAX_BYTES: u64 = 32 * 1024 * 1024;
+/// Top-level boxes walked looking for the index before giving up.
+const VIDEO_BOX_WALK_MAX: usize = 32;
 /// A single frame is seconds of work even for 4K; this only stops a wedged
 /// ffmpeg from holding a thumbnail permit.
 const FFMPEG_TIMEOUT: Duration = Duration::from_secs(30);
@@ -72,6 +84,105 @@ const UPLOAD_THUMB_QUALITIES: [u8; 4] = [65, 50, 35, 20];
 /// Largest still image read whole to render the thumbnail its upload carries.
 const UPLOAD_IMAGE_MAX_BYTES: u64 = 256 * 1024 * 1024;
 
+/// How much memory every thumbnail decode in the daemon may hold at once:
+/// the encoded file plus its decoded pixels.
+///
+/// Without a limit, each of the 16 drain workers decoded its own full-size
+/// photo. A batch of 100-megapixel JPEGs then held about 9 GiB, which swapped the
+/// machine until the watchdog killed the daemon, on every restart
+/// (`docs/BUGS.md` B280). With this budget, a phone photo still decodes beside
+/// several others, and a 100-megapixel one decodes alone.
+const DECODE_BUDGET_BYTES: u64 = 512 * 1024 * 1024;
+
+/// The process-wide [`DecodeBudget`] every thumbnail decode draws from.
+static DECODE_BUDGET: DecodeBudget = DecodeBudget::new(DECODE_BUDGET_BYTES);
+
+/// A counting gate over bytes: [`acquire`](Self::acquire) waits until the cost
+/// fits beside what is already held.
+struct DecodeBudget {
+    limit: u64,
+    used: std::sync::Mutex<u64>,
+    freed: std::sync::Condvar,
+}
+
+/// A share of a [`DecodeBudget`], given back on drop.
+struct DecodePermit<'a> {
+    budget: &'a DecodeBudget,
+    cost: u64,
+}
+
+impl DecodeBudget {
+    const fn new(limit: u64) -> Self {
+        Self {
+            limit,
+            used: std::sync::Mutex::new(0),
+            freed: std::sync::Condvar::new(),
+        }
+    }
+
+    /// Wait until `cost` bytes fit, and hold them. A cost above the limit is
+    /// cut down to the limit, so the largest image waits for an idle budget
+    /// and then runs alone, instead of waiting forever.
+    fn acquire(&self, cost: u64) -> DecodePermit<'_> {
+        let cost = cost.clamp(1, self.limit);
+        let mut used = self
+            .used
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        while *used + cost > self.limit {
+            used = self
+                .freed
+                .wait(used)
+                .unwrap_or_else(std::sync::PoisonError::into_inner);
+        }
+        *used += cost;
+        DecodePermit { budget: self, cost }
+    }
+}
+
+impl Drop for DecodePermit<'_> {
+    fn drop(&mut self) {
+        let mut used = self
+            .budget
+            .used
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        *used -= self.cost;
+        self.budget.freed.notify_all();
+    }
+}
+
+/// What decoding an image of `encoded_len` bytes and `dimensions` costs in
+/// memory: the encoded bytes, the decoded pixels at up to 4 bytes each, and a
+/// second copy of the pixels when [`decode_upright`] rotates them. When the
+/// header gives no dimensions, assume the image is compressed 16 to 1.
+fn decode_cost(encoded_len: u64, dimensions: Option<(u32, u32)>) -> u64 {
+    let pixels = match dimensions {
+        Some((width, height)) => u64::from(width) * u64::from(height) * 4 * 2,
+        None => encoded_len.saturating_mul(16),
+    };
+    encoded_len.saturating_add(pixels)
+}
+
+/// The pixel dimensions in the header of an encoded image, without decoding it.
+fn dimensions_of(bytes: &[u8]) -> Option<(u32, u32)> {
+    image::ImageReader::new(std::io::Cursor::new(bytes))
+        .with_guessed_format()
+        .ok()?
+        .into_dimensions()
+        .ok()
+}
+
+/// [`dimensions_of`] for an image file. Reads only the header.
+fn dimensions_of_file(path: &Path) -> Option<(u32, u32)> {
+    image::ImageReader::open(path)
+        .ok()?
+        .with_guessed_format()
+        .ok()?
+        .into_dimensions()
+        .ok()
+}
+
 /// The aspect ratio (w/h) of an encoded image, read from its header alone — no
 /// pixels are decoded. `None` when the format is unknown or the header is torn.
 fn ratio_of(bytes: &[u8]) -> Option<f64> {
@@ -146,8 +257,8 @@ struct RawPreviewUnavailable;
 /// the photo will never have a thumbnail, and only that verdict is persisted.
 enum ThumbAttempt {
     Made(GeneratedThumb),
-    /// Decoded nothing — a format this build has no decoder for, or a video
-    /// too large to fetch for one frame. Permanent.
+    /// Decoded nothing: a format this build has no decoder for, a video
+    /// ffmpeg takes no frame from, or a `.ts` that is not one. Permanent.
     Undecodable,
     /// The photo couldn't be downloaded. Transient: try again next time.
     Unavailable,
@@ -209,7 +320,14 @@ fn thumbnail_build_may_start(status: &ThumbnailBuildStatus, path: &str) -> CoreR
 /// formats return an undecodable verdict.
 ///
 /// CPU-bound (a 20 MP JPEG is real work), so callers run it on the blocking pool.
+/// Waits for its share of [`DECODE_BUDGET`] first.
 fn scale_thumbnail(bytes: &[u8], name: &str, staging_dir: &Path) -> ScaleAttempt {
+    let _permit = DECODE_BUDGET.acquire(decode_cost(bytes.len() as u64, dimensions_of(bytes)));
+    scale_thumbnail_unbudgeted(bytes, name, staging_dir)
+}
+
+/// [`scale_thumbnail`] for a caller that already holds its [`DecodePermit`].
+fn scale_thumbnail_unbudgeted(bytes: &[u8], name: &str, staging_dir: &Path) -> ScaleAttempt {
     scale_thumbnail_with_exiftool(
         bytes,
         name,
@@ -226,11 +344,7 @@ fn scale_thumbnail_with_exiftool(
     exiftool: &OsStr,
     timeout: Duration,
 ) -> ScaleAttempt {
-    let direct = image::ImageReader::new(std::io::Cursor::new(bytes))
-        .with_guessed_format()
-        .ok()
-        .and_then(|reader| reader.decode().ok());
-    let image = match direct {
+    let image = match decode_upright(bytes) {
         Some(image) => image,
         None if is_raw_image_name(name) => {
             let (preview, orientation) =
@@ -256,6 +370,27 @@ fn scale_thumbnail_with_exiftool(
     encode_thumb(&image)
 }
 
+/// Decode `bytes` and turn the picture the way its EXIF orientation says.
+///
+/// `ImageReader::decode` does not: a phone stores a portrait photo as landscape
+/// pixels plus an orientation tag, so every such thumbnail came out on its
+/// side, and the drain uploaded it to Drive that way for every client to show
+/// (`docs/BUGS.md` B226).
+fn decode_upright(bytes: &[u8]) -> Option<image::DynamicImage> {
+    use image::ImageDecoder as _;
+    let mut decoder = image::ImageReader::new(std::io::Cursor::new(bytes))
+        .with_guessed_format()
+        .ok()?
+        .into_decoder()
+        .ok()?;
+    let orientation = decoder
+        .orientation()
+        .unwrap_or(image::metadata::Orientation::NoTransforms);
+    let mut image = image::DynamicImage::from_decoder(decoder).ok()?;
+    image.apply_orientation(orientation);
+    Some(image)
+}
+
 /// Shrink a decoded image to a [`THUMB_EDGE`] JPEG, keeping its aspect ratio.
 fn encode_thumb(image: &image::DynamicImage) -> ScaleAttempt {
     let (width, height) = (image.width(), image.height());
@@ -417,6 +552,16 @@ fn exiftool_query(
     serde_json::from_slice(&output).map_err(|_| RawPreviewUnavailable)
 }
 
+/// Whether [`upload_thumbnails`] can make a thumbnail for a file `name` of
+/// `size` bytes, asked before the file is on disk: an image small enough to
+/// decode, or a video while ffmpeg is installed.
+pub(crate) fn can_make_thumbnail(name: &str, size: u64) -> bool {
+    if is_video_name(name) {
+        return ffmpeg_available();
+    }
+    is_thumbnail_image_name(name) && size <= UPLOAD_IMAGE_MAX_BYTES
+}
+
 /// Whether `name` is a video, whose thumbnail is a frame ffmpeg grabs rather
 /// than a picture the image decoder can scale.
 fn is_video_name(name: &str) -> bool {
@@ -444,21 +589,6 @@ fn warn_ffmpeg_missing() {
     });
 }
 
-/// A thumbnail from one frame of a downloaded video, which ffmpeg reads from a
-/// staging copy. See [`video_file_thumbnail`].
-fn video_thumbnail(
-    bytes: &[u8],
-    name: &str,
-    staging_dir: &Path,
-    ffmpeg: &OsStr,
-    timeout: Duration,
-) -> ScaleAttempt {
-    let Some(file) = RawTempFile::create_in(staging_dir, bytes, name) else {
-        return ScaleAttempt::Unavailable;
-    };
-    video_file_thumbnail(&file.0, ffmpeg, timeout)
-}
-
 /// A thumbnail from one frame of the video at `path`. A second in, past the
 /// black lead-in most clips open on, and the first frame for a clip shorter than
 /// that. ffmpeg applies the clip's rotation, so a portrait phone video comes out
@@ -491,6 +621,151 @@ fn video_file_thumbnail(path: &Path, ffmpeg: &OsStr, timeout: Duration) -> Scale
     ScaleAttempt::Undecodable
 }
 
+/// What a thumbnail is made from.
+enum Fetched {
+    /// The thumbnail itself, from the server.
+    Ready(Vec<u8>),
+    /// Nothing: a video with no server thumbnail, and no ffmpeg to take one.
+    Nothing,
+    /// A whole image.
+    Whole(Vec<u8>),
+    Video(VideoSample),
+}
+
+/// The parts of a video its thumbnail needs, downloaded: the start of the
+/// file, and for an MP4 or MOV whose index is further in, that index.
+struct VideoSample {
+    /// The whole file's length.
+    size: u64,
+    head: Vec<u8>,
+    /// The `moov` box and its offset, when it is not inside `head`.
+    index: Option<(u64, Vec<u8>)>,
+}
+
+impl VideoSample {
+    /// Whether this could be an MPEG transport stream: one opens on the 0x47
+    /// sync byte, and repeats it every 188-byte packet. Only asked of `.ts`
+    /// files, which are TypeScript source as often as they are video.
+    fn is_transport_stream(&self) -> bool {
+        self.head.first() == Some(&0x47) && self.head.get(188).is_none_or(|&byte| byte == 0x47)
+    }
+}
+
+/// Download what a thumbnail of the video `reader` reads needs. A file of up
+/// to [`VIDEO_WHOLE_MAX_BYTES`] comes whole. A larger one brings its first
+/// [`VIDEO_HEAD_BYTES`], which is all a stream format (Matroska, WebM, MPEG-TS,
+/// AVI) needs for a frame, plus the index of an ISO media file (MP4, MOV, 3GP)
+/// written with its index after the media data, which is how most cameras and
+/// phones write it.
+async fn sample_video(reader: &dyn RevisionRead) -> DriveResult<VideoSample> {
+    let size = reader.size();
+    if size <= VIDEO_WHOLE_MAX_BYTES {
+        let head = reader.read_at(0, size).await?;
+        return Ok(VideoSample {
+            size,
+            head,
+            index: None,
+        });
+    }
+    let head = reader.read_at(0, VIDEO_HEAD_BYTES).await?;
+    let index = match iso_media_index(reader, &head, size).await? {
+        Some((offset, len)) if offset.saturating_add(len) > head.len() as u64 => {
+            Some((offset, reader.read_at(offset, len).await?))
+        }
+        _ => None,
+    };
+    Ok(VideoSample { size, head, index })
+}
+
+/// Where the `moov` box of an ISO media file sits, as `(offset, length)`.
+/// `None` for a file that is not one, or whose index is missing, oversized or
+/// past [`VIDEO_BOX_WALK_MAX`] boxes. Box headers past `head` are read one at a
+/// time, 16 bytes each.
+async fn iso_media_index(
+    reader: &dyn RevisionRead,
+    head: &[u8],
+    size: u64,
+) -> DriveResult<Option<(u64, u64)>> {
+    const FIRST_BOXES: [&[u8; 4]; 6] = [b"ftyp", b"moov", b"mdat", b"wide", b"free", b"skip"];
+    if !head
+        .get(4..8)
+        .is_some_and(|kind| FIRST_BOXES.iter().any(|known| kind == *known))
+    {
+        return Ok(None);
+    }
+    let mut offset = 0u64;
+    for _ in 0..VIDEO_BOX_WALK_MAX {
+        if offset.saturating_add(8) > size {
+            break;
+        }
+        let header = match usize::try_from(offset)
+            .ok()
+            .and_then(|start| head.get(start..start.checked_add(16)?))
+        {
+            Some(header) => header.to_vec(),
+            None => reader.read_at(offset, 16).await?,
+        };
+        let Some((kind, len)) = iso_box_header(&header, size - offset) else {
+            break;
+        };
+        if kind == *b"moov" {
+            return Ok((len <= VIDEO_INDEX_MAX_BYTES).then_some((offset, len)));
+        }
+        offset = offset.saturating_add(len);
+    }
+    Ok(None)
+}
+
+/// The type and length of the ISO box whose header starts `header`, of a box
+/// that may run at most `left` bytes to the end of the file.
+fn iso_box_header(header: &[u8], left: u64) -> Option<([u8; 4], u64)> {
+    let size = u32::from_be_bytes(header.get(0..4)?.try_into().ok()?);
+    let kind: [u8; 4] = header.get(4..8)?.try_into().ok()?;
+    let len = match size {
+        // Runs to the end of the file.
+        0 => left,
+        // The real length follows as 64 bits.
+        1 => u64::from_be_bytes(header.get(8..16)?.try_into().ok()?),
+        len => u64::from(len),
+    };
+    (8..=left).contains(&len).then_some((kind, len))
+}
+
+/// A thumbnail from one frame of a downloaded [`VideoSample`]. The sample is
+/// laid out in a staging file at the offsets it came from, so ffmpeg finds an
+/// index where the file's own boxes say it is. The gap between holds no data
+/// and costs no disk.
+fn video_sample_thumbnail(
+    sample: &VideoSample,
+    name: &str,
+    staging_dir: &Path,
+    ffmpeg: &OsStr,
+    timeout: Duration,
+) -> ScaleAttempt {
+    let transport_stream_name = Path::new(name)
+        .extension()
+        .is_some_and(|extension| extension.eq_ignore_ascii_case("ts"));
+    if transport_stream_name && !sample.is_transport_stream() {
+        return ScaleAttempt::Undecodable;
+    }
+    let Some(file) = RawTempFile::create_in(staging_dir, &sample.head, name) else {
+        return ScaleAttempt::Unavailable;
+    };
+    if let Some((offset, index)) = &sample.index {
+        let laid_out = OpenOptions::new()
+            .write(true)
+            .open(&file.0)
+            .and_then(|staged| {
+                staged.write_all_at(index, *offset)?;
+                staged.set_len(sample.size.max(offset + index.len() as u64))
+            });
+        if laid_out.is_err() {
+            return ScaleAttempt::Unavailable;
+        }
+    }
+    video_file_thumbnail(&file.0, ffmpeg, timeout)
+}
+
 /// The thumbnail to attach to an upload of the local file at `path`, which is
 /// named `name` in Drive. Without one, Drive's own apps show a generic icon and
 /// the gallery has to download the whole file to make its own.
@@ -517,11 +792,20 @@ fn upload_thumbnails_with(
         }
         video_file_thumbnail(path, ffmpeg, FFMPEG_TIMEOUT)
     } else if is_thumbnail_image_name(name) {
-        let fits = std::fs::metadata(path).is_ok_and(|meta| meta.len() <= UPLOAD_IMAGE_MAX_BYTES);
-        let Some(bytes) = fits.then(|| std::fs::read(path).ok()).flatten() else {
+        let Some(len) = std::fs::metadata(path)
+            .ok()
+            .map(|meta| meta.len())
+            .filter(|len| *len <= UPLOAD_IMAGE_MAX_BYTES)
+        else {
             return Vec::new();
         };
-        scale_thumbnail(&bytes, name, staging_dir)
+        // Taken before the read, so the encoded bytes count against the
+        // budget too.
+        let _permit = DECODE_BUDGET.acquire(decode_cost(len, dimensions_of_file(path)));
+        let Ok(bytes) = std::fs::read(path) else {
+            return Vec::new();
+        };
+        scale_thumbnail_unbudgeted(&bytes, name, staging_dir)
     } else {
         return Vec::new();
     };
@@ -743,6 +1027,7 @@ impl Core {
             favorite: photo.favorite,
             group_size: photo.group_size as u32,
             has_raw: photo.has_raw,
+            place_id: photo.place_id,
         }
     }
 
@@ -1264,10 +1549,10 @@ impl Core {
             .map(|item| (item.uid.clone(), item.name.clone()))
             .collect();
 
-        // Proton only stores server-generated thumbnails for nodes in Photos.
-        // These requests come exclusively from ordinary Drive, Shared and Trash
-        // views, so downloading a remote thumbnail here would be a guaranteed
-        // miss. Generate directly from the full image and cache the result.
+        // Drive makes no thumbnails itself; a file has one only when its
+        // uploader attached it, as this client and Proton's apps do. The
+        // generation step asks for that first, and only makes one from the
+        // file's content without it.
         let mut wanted = Vec::new();
         let mut seen = HashSet::new();
         for (raw, uid, modified) in &parsed {
@@ -1317,7 +1602,7 @@ impl Core {
         let next = |current| if current == u64::MAX { 1 } else { current + 1 };
         let previous = self
             .file_thumb_generation
-            .fetch_update(Ordering::SeqCst, Ordering::SeqCst, |current| {
+            .try_update(Ordering::SeqCst, Ordering::SeqCst, |current| {
                 Some(next(current))
             })
             .expect("generation update always succeeds");
@@ -1418,7 +1703,10 @@ impl Core {
                             return (uid, ThumbAttempt::Cancelled);
                         }
                         let video = is_video_name(&name);
-                        if video && !ffmpeg_available() {
+                        // Without ffmpeg a video can still have its uploader's
+                        // thumbnail, but Photos has asked the server already.
+                        let can_sample = !video || ffmpeg_available();
+                        if !can_sample && matches!(job, ThumbJob::Photos) {
                             return (uid, ThumbAttempt::Unavailable);
                         }
 
@@ -1467,21 +1755,34 @@ impl Core {
                             return (uid, ThumbAttempt::Cancelled);
                         }
 
-                        // A video is downloaded whole for one frame, so a long
-                        // recording is not worth it — and would not fit in memory.
-                        if video {
-                            match core.photos().get_node(&uid).await {
-                                Ok(Some(node)) if node_size(&node) > VIDEO_THUMB_MAX_BYTES => {
-                                    info!(%uid, size = node_size(&node), "video too large for a local thumbnail");
-                                    return (uid, ThumbAttempt::Undecodable);
-                                }
-                                Ok(Some(_)) => {}
-                                Ok(None) | Err(_) => return (uid, ThumbAttempt::Unavailable),
-                            }
-                        }
-
                         let download_uid = uid.clone();
-                        let download = async move { client.download_file(&download_uid).await };
+                        let drive = core.drive.clone();
+                        let download = async move {
+                            // Photos asked the server in one batch already. A
+                            // file view's or a build's file may carry a
+                            // thumbnail its uploader made, which costs one
+                            // small download instead of its content.
+                            if !matches!(job, ThumbJob::Photos)
+                                && let Some(bytes) = drive
+                                    .download_thumbnail(&download_uid, ThumbnailType::Thumbnail)
+                                    .await?
+                                    .filter(|bytes| !bytes.is_empty())
+                            {
+                                return Ok(Fetched::Ready(bytes));
+                            }
+                            if !can_sample {
+                                return Ok(Fetched::Nothing);
+                            }
+                            if video {
+                                let reader = drive.open_revision(&download_uid).await?;
+                                sample_video(reader.as_ref()).await.map(Fetched::Video)
+                            } else {
+                                client
+                                    .download_file(&download_uid)
+                                    .await
+                                    .map(Fetched::Whole)
+                            }
+                        };
                         tokio::pin!(download);
                         let downloaded = match job {
                             ThumbJob::Files(_) => loop {
@@ -1519,10 +1820,10 @@ impl Core {
                         let Some(downloaded) = downloaded else {
                             return (uid, ThumbAttempt::Cancelled);
                         };
-                        let bytes = match downloaded {
-                            Ok(bytes) => bytes,
+                        let fetched = match downloaded {
+                            Ok(fetched) => fetched,
                             Err(e) => {
-                                warn!(%uid, error = %e, "image download for thumbnail failed");
+                                warn!(%uid, error = %e, "download for a thumbnail failed");
                                 return (uid, ThumbAttempt::Unavailable);
                             }
                         };
@@ -1532,18 +1833,20 @@ impl Core {
                         // Decoding + scaling a 20 MP JPEG is CPU-bound and would
                         // stall the runtime's worker; hand it to the blocking pool.
                         let staging_dir = core.cache.raw_thumbnail_staging_dir().to_path_buf();
-                        let made = tokio::task::spawn_blocking(move || {
-                            if video {
-                                video_thumbnail(
-                                    &bytes,
-                                    &name,
-                                    &staging_dir,
-                                    OsStr::new("ffmpeg"),
-                                    FFMPEG_TIMEOUT,
-                                )
-                            } else {
-                                scale_thumbnail(&bytes, &name, &staging_dir)
-                            }
+                        let made = tokio::task::spawn_blocking(move || match fetched {
+                            Fetched::Video(sample) => video_sample_thumbnail(
+                                &sample,
+                                &name,
+                                &staging_dir,
+                                OsStr::new("ffmpeg"),
+                                FFMPEG_TIMEOUT,
+                            ),
+                            Fetched::Whole(bytes) => scale_thumbnail(&bytes, &name, &staging_dir),
+                            Fetched::Nothing => ScaleAttempt::Unavailable,
+                            Fetched::Ready(bytes) => match ratio_of(&bytes) {
+                                Some(ratio) => ScaleAttempt::Made(GeneratedThumb { bytes, ratio }),
+                                None => ScaleAttempt::Undecodable,
+                            },
                         })
                         .await
                         .unwrap_or(ScaleAttempt::Unavailable);
@@ -1727,7 +2030,7 @@ impl Core {
                     if seen_folders.insert(entry.uid) {
                         folders.push(folder.join(entry.name));
                     }
-                } else if is_thumbnail_image_name(&entry.name) {
+                } else if is_thumbnail_media_name(&entry.name, Some(entry.size)) {
                     match parse_uid(&entry.uid) {
                         Some(uid) if seen_images.insert(uid.clone()) => {
                             found_here += 1;
@@ -2089,18 +2392,83 @@ impl Core {
     }
 }
 
+#[cfg(test)]
+mod decode_budget_tests {
+    use super::{DecodeBudget, decode_cost};
+    use std::sync::Arc;
+    use std::sync::atomic::{AtomicBool, Ordering};
+    use std::time::Duration;
+
+    /// A decode that does not fit beside the ones running waits for them,
+    /// instead of every drain worker decoding at once (`docs/BUGS.md` B280).
+    #[test]
+    fn a_decode_over_the_budget_waits_for_the_running_one() {
+        let budget = Arc::new(DecodeBudget::new(100));
+        let first = budget.acquire(60);
+        let started = Arc::new(AtomicBool::new(false));
+        let waiter = {
+            let (budget, started) = (budget.clone(), started.clone());
+            std::thread::spawn(move || {
+                let _second = budget.acquire(60);
+                started.store(true, Ordering::SeqCst);
+            })
+        };
+        std::thread::sleep(Duration::from_millis(100));
+        assert!(
+            !started.load(Ordering::SeqCst),
+            "second decode ran over budget"
+        );
+        drop(first);
+        waiter.join().expect("waiter");
+        assert!(started.load(Ordering::SeqCst));
+    }
+
+    /// Decodes that fit together run together.
+    #[test]
+    fn small_decodes_share_the_budget() {
+        let budget = DecodeBudget::new(100);
+        let _a = budget.acquire(30);
+        let _b = budget.acquire(30);
+        let _c = budget.acquire(30);
+    }
+
+    /// An image bigger than the whole budget still decodes, alone, rather than
+    /// waiting forever.
+    #[test]
+    fn an_image_over_the_whole_budget_still_decodes() {
+        let budget = DecodeBudget::new(100);
+        drop(budget.acquire(10_000));
+        let _again = budget.acquire(100);
+    }
+
+    /// The cost of the 102-megapixel JPEG that set off B280 fills the real
+    /// budget, so it never decodes beside another one.
+    #[test]
+    fn a_hundred_megapixel_photo_costs_the_whole_budget() {
+        let cost = decode_cost(97_266_141, Some((11_656, 8_742)));
+        assert!(cost >= super::DECODE_BUDGET_BYTES);
+        let phone = decode_cost(4_000_000, Some((4_000, 3_000)));
+        assert!(phone * 4 < super::DECODE_BUDGET_BYTES);
+    }
+}
+
 #[cfg(test)]
 mod thumb_tests {
     use super::{
-        RawTempFile, ScaleAttempt, THUMB_EDGE, UPLOAD_THUMB_MAX_BYTES, exiftool_binary,
-        fit_upload_thumb, is_video_name, ratio_of, scale_thumbnail, scale_thumbnail_with_exiftool,
-        similar_hashes, thumbnail_build_may_start, upload_thumbnails_with, video_thumbnail,
+        RawTempFile, ScaleAttempt, THUMB_EDGE, UPLOAD_IMAGE_MAX_BYTES, UPLOAD_THUMB_MAX_BYTES,
+        VIDEO_HEAD_BYTES, VIDEO_WHOLE_MAX_BYTES, VideoSample, can_make_thumbnail, exiftool_binary,
+        ffmpeg_available, fit_upload_thumb, is_video_name, ratio_of, sample_video, scale_thumbnail,
+        scale_thumbnail_with_exiftool, similar_hashes, thumbnail_build_may_start,
+        upload_thumbnails_with, video_sample_thumbnail,
     };
+    use crate::drive::RevisionRead;
     use pdfs_core::control::{ThumbnailBuildStatus, is_thumbnail_image_name};
     use proton_drive_rs::ThumbnailType;
+    use proton_drive_rs::proton_sdk::error::Result as DriveResult;
     use std::collections::HashMap;
     use std::ffi::OsStr;
     use std::os::unix::fs::PermissionsExt as _;
+    use std::sync::atomic::{AtomicU64, Ordering};
     use std::time::Duration;
 
     /// A `width`×`height` JPEG, standing in for a camera photo the server never
@@ -2149,6 +2517,64 @@ mod thumb_tests {
         assert_eq!(ratio_of(&thumb.bytes).map(|r| r < 1.0), Some(true));
     }
 
+    /// `jpeg` with an EXIF APP1 segment that carries only `orientation`.
+    fn jpeg_with_orientation(width: u32, height: u32, orientation: u16) -> Vec<u8> {
+        let plain = jpeg(width, height);
+        let mut tiff = Vec::new();
+        tiff.extend_from_slice(b"II*\0");
+        tiff.extend_from_slice(&8u32.to_le_bytes());
+        tiff.extend_from_slice(&1u16.to_le_bytes());
+        tiff.extend_from_slice(&0x0112u16.to_le_bytes());
+        tiff.extend_from_slice(&3u16.to_le_bytes());
+        tiff.extend_from_slice(&1u32.to_le_bytes());
+        tiff.extend_from_slice(&orientation.to_le_bytes());
+        tiff.extend_from_slice(&[0, 0]);
+        tiff.extend_from_slice(&0u32.to_le_bytes());
+        let mut app1 = b"Exif\0\0".to_vec();
+        app1.extend_from_slice(&tiff);
+        let mut out = plain[..2].to_vec();
+        out.extend_from_slice(&[0xFF, 0xE1]);
+        out.extend_from_slice(&u16::try_from(app1.len() + 2).unwrap().to_be_bytes());
+        out.extend_from_slice(&app1);
+        out.extend_from_slice(&plain[2..]);
+        out
+    }
+
+    /// A phone stores a portrait photo as landscape pixels and an EXIF
+    /// orientation; its thumbnail came out on its side (`docs/BUGS.md` B226).
+    /// A Takeout photo is copied out of its archive only when a thumbnail can
+    /// be made from the copy.
+    #[test]
+    fn only_a_photo_that_can_have_a_thumbnail_is_worth_copying_out() {
+        assert!(can_make_thumbnail("IMG_1.jpg", 4 << 20));
+        assert!(can_make_thumbnail("Screenshot.png", 4 << 20));
+        assert!(!can_make_thumbnail("IMG_1.jpg", UPLOAD_IMAGE_MAX_BYTES + 1));
+        assert!(!can_make_thumbnail("notes.txt", 10));
+        assert_eq!(can_make_thumbnail("clip.mp4", 1 << 30), ffmpeg_available());
+    }
+
+    #[test]
+    fn a_thumbnail_is_turned_the_way_its_exif_says() {
+        let ScaleAttempt::Made(thumb) = scale_thumbnail(
+            &jpeg_with_orientation(2000, 1000, 6),
+            "portrait.jpg",
+            &std::env::temp_dir(),
+        ) else {
+            panic!("a JPEG scales");
+        };
+        assert!(thumb.ratio < 1.0, "turned upright: {}", thumb.ratio);
+        assert_eq!(ratio_of(&thumb.bytes).map(|r| r < 1.0), Some(true));
+
+        let ScaleAttempt::Made(level) = scale_thumbnail(
+            &jpeg_with_orientation(2000, 1000, 1),
+            "landscape.jpg",
+            &std::env::temp_dir(),
+        ) else {
+            panic!("a JPEG scales");
+        };
+        assert!(level.ratio > 1.0);
+    }
+
     #[test]
     fn undecodable_bytes_are_not_a_thumbnail() {
         // What a photo in a format this build has no decoder for looks like: the
@@ -2275,6 +2701,199 @@ mod thumb_tests {
         std::env::temp_dir().join(format!("pdfs-{test}-{}", std::process::id()))
     }
 
+    /// A sample of a video small enough to come whole.
+    fn whole(bytes: &[u8]) -> VideoSample {
+        VideoSample {
+            size: bytes.len() as u64,
+            head: bytes.to_vec(),
+            index: None,
+        }
+    }
+
+    fn block_on<F: std::future::Future>(future: F) -> F::Output {
+        tokio::runtime::Builder::new_current_thread()
+            .build()
+            .unwrap()
+            .block_on(future)
+    }
+
+    /// A Drive revision of `size` bytes, zero except for the parts written in,
+    /// that counts the bytes read from it. Stands for a recording far larger
+    /// than a test should hold in memory.
+    struct FakeRevision {
+        size: u64,
+        parts: Vec<(u64, Vec<u8>)>,
+        read: AtomicU64,
+    }
+
+    impl FakeRevision {
+        fn new(size: u64) -> Self {
+            Self {
+                size,
+                parts: Vec::new(),
+                read: AtomicU64::new(0),
+            }
+        }
+
+        fn with(mut self, offset: u64, bytes: Vec<u8>) -> Self {
+            self.parts.push((offset, bytes));
+            self
+        }
+    }
+
+    #[async_trait::async_trait]
+    impl RevisionRead for FakeRevision {
+        fn size(&self) -> u64 {
+            self.size
+        }
+
+        fn block_sizes(&self) -> &[u64] {
+            &[]
+        }
+
+        async fn read_at(&self, offset: u64, length: u64) -> DriveResult<Vec<u8>> {
+            let end = offset.saturating_add(length).min(self.size);
+            let mut out = vec![0u8; end.saturating_sub(offset) as usize];
+            for (start, bytes) in &self.parts {
+                let part_end = start + bytes.len() as u64;
+                let (from, to) = (offset.max(*start), end.min(part_end));
+                if from < to {
+                    out[(from - offset) as usize..(to - offset) as usize]
+                        .copy_from_slice(&bytes[(from - start) as usize..(to - start) as usize]);
+                }
+            }
+            self.read.fetch_add(out.len() as u64, Ordering::Relaxed);
+            Ok(out)
+        }
+    }
+
+    /// An ISO media box of `len` bytes, of which only the header is returned.
+    fn iso_box_header(kind: &[u8; 4], len: u64) -> Vec<u8> {
+        if let Ok(len) = u32::try_from(len) {
+            [&len.to_be_bytes()[..], kind].concat()
+        } else {
+            [&1u32.to_be_bytes()[..], kind, &len.to_be_bytes()[..]].concat()
+        }
+    }
+
+    const GIB: u64 = 1024 * 1024 * 1024;
+
+    #[test]
+    fn a_large_stream_video_downloads_its_head_alone() {
+        let mut head = vec![0u8; 188 * 2];
+        head[0] = 0x47;
+        head[188] = 0x47;
+        let revision = FakeRevision::new(9 * GIB).with(0, head);
+        let sample = block_on(sample_video(&revision)).unwrap();
+        assert_eq!(sample.size, 9 * GIB);
+        assert_eq!(sample.head.len() as u64, VIDEO_HEAD_BYTES);
+        assert!(sample.index.is_none());
+        assert!(sample.is_transport_stream());
+        assert_eq!(revision.read.load(Ordering::Relaxed), VIDEO_HEAD_BYTES);
+    }
+
+    /// A camera MP4 keeps its index after gigabytes of media data. The sample
+    /// is the head, the box headers on the way, and the index itself.
+    #[test]
+    fn a_large_mp4_downloads_its_head_and_its_index() {
+        let ftyp = [
+            iso_box_header(b"ftyp", 24),
+            b"isom\0\0\0\0mp41isom".to_vec(),
+        ]
+        .concat();
+        let mdat_len = 6 * GIB;
+        let moov_at = ftyp.len() as u64 + mdat_len;
+        let moov = [iso_box_header(b"moov", 4096), vec![7u8; 4088]].concat();
+        let size = moov_at + moov.len() as u64;
+        let revision = FakeRevision::new(size)
+            .with(0, ftyp.clone())
+            .with(ftyp.len() as u64, iso_box_header(b"mdat", mdat_len))
+            .with(moov_at, moov.clone());
+
+        let sample = block_on(sample_video(&revision)).unwrap();
+        assert_eq!(sample.index, Some((moov_at, moov)));
+        assert!(
+            revision.read.load(Ordering::Relaxed) <= VIDEO_HEAD_BYTES + 4096 + 16,
+            "read {} bytes",
+            revision.read.load(Ordering::Relaxed)
+        );
+    }
+
+    #[test]
+    fn an_mp4_with_its_index_up_front_downloads_its_head_alone() {
+        let ftyp = [iso_box_header(b"ftyp", 16), b"isom\0\0\0\0".to_vec()].concat();
+        let moov = [iso_box_header(b"moov", 64), vec![1u8; 56]].concat();
+        let revision = FakeRevision::new(GIB)
+            .with(0, ftyp.clone())
+            .with(ftyp.len() as u64, moov)
+            .with(80, iso_box_header(b"mdat", GIB - 80));
+        let sample = block_on(sample_video(&revision)).unwrap();
+        assert!(sample.index.is_none());
+        assert_eq!(revision.read.load(Ordering::Relaxed), VIDEO_HEAD_BYTES);
+    }
+
+    #[test]
+    fn a_small_video_downloads_whole() {
+        let revision = FakeRevision::new(VIDEO_WHOLE_MAX_BYTES).with(0, vec![3u8; 64]);
+        let sample = block_on(sample_video(&revision)).unwrap();
+        assert_eq!(sample.head.len() as u64, VIDEO_WHOLE_MAX_BYTES);
+        assert!(sample.index.is_none());
+    }
+
+    /// `.ts` that is TypeScript reaches ffmpeg never: the sync byte is missing,
+    /// and that is a final answer, not a retry.
+    #[test]
+    fn a_ts_without_the_sync_byte_is_no_video() {
+        let attempt = video_sample_thumbnail(
+            &whole(b"export const answer = 42;"),
+            "bundle.ts",
+            &std::env::temp_dir(),
+            OsStr::new("pdfs-ffmpeg-deliberately-absent"),
+            Duration::from_millis(10),
+        );
+        assert!(matches!(attempt, ScaleAttempt::Undecodable));
+    }
+
+    /// ffmpeg reads the index where the file's own boxes put it, so the staging
+    /// file has the full length and the index at its offset.
+    #[test]
+    fn the_index_is_staged_at_its_own_offset() {
+        let tmp = scratch("video-index");
+        let frame = tmp.join("frame.jpg");
+        std::fs::create_dir_all(&tmp).unwrap();
+        std::fs::write(&frame, jpeg(640, 360)).unwrap();
+        let size: u64 = 3 * GIB;
+        let at: u64 = size - 4096;
+        // Arguments: -nostdin -loglevel error -ss <seek> -i <path> …
+        let ffmpeg = fake_ffmpeg(
+            &tmp,
+            &format!(
+                "[ \"$(stat -c %s \"$7\")\" = {size} ] && \
+                 [ \"$(tail -c +{} \"$7\" | head -c 4)\" = moov ] && cat '{}'",
+                // The box type, after its 4-byte length; `tail` counts from 1.
+                at + 5,
+                frame.display()
+            ),
+        );
+        let sample = VideoSample {
+            size,
+            head: vec![0u8; 1024],
+            index: Some((
+                at,
+                [iso_box_header(b"moov", 4096), vec![0u8; 4088]].concat(),
+            )),
+        };
+        let attempt = video_sample_thumbnail(
+            &sample,
+            "clip.mp4",
+            &tmp,
+            ffmpeg.as_os_str(),
+            Duration::from_secs(10),
+        );
+        std::fs::remove_dir_all(&tmp).unwrap();
+        assert!(matches!(attempt, ScaleAttempt::Made(_)));
+    }
+
     #[test]
     fn a_video_frame_becomes_a_thumbnail() {
         let tmp = scratch("video-frame");
@@ -2283,8 +2902,8 @@ mod thumb_tests {
         std::fs::write(&frame, jpeg(1080, 1920)).unwrap();
         let ffmpeg = fake_ffmpeg(&tmp, &format!("cat '{}'", frame.display()));
 
-        let ScaleAttempt::Made(thumb) = video_thumbnail(
-            b"video bytes",
+        let ScaleAttempt::Made(thumb) = video_sample_thumbnail(
+            &whole(b"video bytes"),
             "clip.mp4",
             &tmp,
             ffmpeg.as_os_str(),
@@ -2300,8 +2919,8 @@ mod thumb_tests {
     fn a_video_ffmpeg_cannot_read_is_a_permanent_miss() {
         let tmp = scratch("video-broken");
         let ffmpeg = fake_ffmpeg(&tmp, "exit 1");
-        let attempt = video_thumbnail(
-            b"not a video",
+        let attempt = video_sample_thumbnail(
+            &whole(b"not a video"),
             "clip.mp4",
             &tmp,
             ffmpeg.as_os_str(),
@@ -2313,8 +2932,8 @@ mod thumb_tests {
 
     #[test]
     fn missing_ffmpeg_is_retryable() {
-        let attempt = video_thumbnail(
-            b"video bytes",
+        let attempt = video_sample_thumbnail(
+            &whole(b"video bytes"),
             "clip.mp4",
             &std::env::temp_dir(),
             OsStr::new("pdfs-ffmpeg-deliberately-absent"),
@@ -2330,9 +2949,12 @@ mod thumb_tests {
         let path = std::env::var_os("PDFS_VIDEO_FIXTURE").expect("PDFS_VIDEO_FIXTURE");
         let path = std::path::PathBuf::from(path);
         let name = path.file_name().unwrap().to_string_lossy();
-        let bytes = std::fs::read(&path).unwrap();
-        let ScaleAttempt::Made(thumb) = video_thumbnail(
-            &bytes,
+        // Through the same partial download a Drive video gets.
+        let revision = FakeRevision::new(std::fs::read(&path).unwrap().len() as u64)
+            .with(0, std::fs::read(&path).unwrap());
+        let sample = block_on(sample_video(&revision)).unwrap();
+        let ScaleAttempt::Made(thumb) = video_sample_thumbnail(
+            &sample,
             &name,
             &std::env::temp_dir(),
             OsStr::new("ffmpeg"),

crates/pdfs-fuse/src/profile.rs

@@ -15,6 +15,7 @@ use pdfs_core::control::RestorableFolder;
 use pdfs_core::mounts::MountMode;
 use pdfs_core::profile::{
     PROFILE_DIR_NAME, PROFILE_FILE_NAME, PROFILE_VERSION, Profile, ProfileFolder, ProfilePin,
+    is_profile_file_name, profile_file_name, saved_folder,
 };
 use pdfs_core::{CoreError, CoreResult};
 use proton_drive_rs::proton_sdk::ids::NodeUid;
@@ -66,9 +67,14 @@ impl Core {
         });
     }
 
-    /// Serialize this machine's arrangement and upload it to `profile.json`
-    /// inside the device's `.proton-drive-linux` folder, replacing any existing
-    /// one.
+    /// Serialize this machine's arrangement and upload it to its own
+    /// `profile-<machine id>.json` inside the device's `.proton-drive-linux`
+    /// folder, replacing any existing one.
+    ///
+    /// Each machine writes its own file because several computers may sync
+    /// into one device. They used to share `profile.json`, and each save
+    /// replaced the other computers' folders with its own (B252). That file is
+    /// left as it is, so a client before 3.5.0 still finds it.
     ///
     /// Does nothing when no device is registered: a machine that has never
     /// synced a folder has nothing to describe, and registering a device just to
@@ -85,7 +91,11 @@ impl Core {
             CoreError::internal(format!("bad device root uid: {}", device.root_uid))
         })?;
 
-        let profile = self.build_profile(&device.uid)?;
+        let machine_id = pdfs_core::config::AppDirs::new()
+            .and_then(|dirs| dirs.machine_id())
+            .map_err(|e| CoreError::internal(format!("machine id: {e}")))?;
+        let file_name = profile_file_name(&machine_id);
+        let profile = self.build_profile(&device.uid, &machine_id)?;
         let bytes = profile.to_bytes().map_err(CoreError::internal)?;
         let len = bytes.len() as i64;
 
@@ -97,7 +107,7 @@ impl Core {
         // same name: the profile is a single mutable record, and a folder with
         // `profile.json` and `profile (1).json` in it teaches the restore
         // nothing about which to trust.
-        let existing = self.find_device_child_file(&dir_uid, PROFILE_FILE_NAME)?;
+        let existing = self.find_device_child_file(&dir_uid, &file_name)?;
         match existing {
             Some(uid) => self
                 .rt
@@ -114,7 +124,7 @@ impl Core {
                 self.rt
                     .block_on(self.drive.upload_file_replacing_draft_from(
                         &dir_uid,
-                        PROFILE_FILE_NAME,
+                        &file_name,
                         "application/json",
                         Cursor::new(bytes),
                         len,
@@ -130,20 +140,12 @@ impl Core {
     }
 
     /// Snapshot the local arrangement into a [`Profile`].
-    fn build_profile(&self, device_uid: &str) -> CoreResult<Profile> {
-        let folders = self
-            .db
-            .sync_folder_list()
-            .map_err(|e| CoreError::internal(format!("db: {e:?}")))?
-            .into_iter()
-            .map(|f| ProfileFolder {
-                remote_uid: f.remote_uid,
-                local_path: f.local_path,
-                // A queued switch is where the user asked the folder to be, so
-                // that is what the next machine should set up.
-                mode: MountMode::from(f.pending_mode.unwrap_or(f.mode).as_str()),
-            })
-            .collect();
+    fn build_profile(&self, device_uid: &str, machine_id: &str) -> CoreResult<Profile> {
+        let folders = profile_folders(
+            self.db
+                .sync_folder_list()
+                .map_err(|e| CoreError::internal(format!("db: {e:?}")))?,
+        );
         let pins = self
             .db
             .pin_list()
@@ -162,6 +164,7 @@ impl Core {
             version: PROFILE_VERSION,
             device_uid: device_uid.to_string(),
             hostname: this_hostname(),
+            machine_id: Some(machine_id.to_string()),
             saved_at: now_secs(),
             folders,
             pins,
@@ -197,6 +200,31 @@ impl Core {
             .map(|n| n.uid))
     }
 
+    /// The untrashed files directly under `parent_uid` whose name passes
+    /// `keep`.
+    fn device_child_files(
+        &self,
+        parent_uid: &NodeUid,
+        keep: impl Fn(&str) -> bool,
+    ) -> CoreResult<Vec<NodeUid>> {
+        let uids = self
+            .rt
+            .block_on(self.drive.enumerate_folder_children_node_uids(parent_uid))
+            .map_err(|e| CoreError::from_api(&e, "list device root"))?;
+        if uids.is_empty() {
+            return Ok(Vec::new());
+        }
+        let nodes = self
+            .rt
+            .block_on(self.drive.enumerate_nodes(&uids))
+            .map_err(|e| CoreError::from_api(&e, "resolve device root children"))?;
+        Ok(nodes
+            .into_iter()
+            .filter(|n| !n.is_folder() && !n.trashed && keep(&n.name))
+            .map(|n| n.uid)
+            .collect())
+    }
+
     /// The device's `.proton-drive-linux` folder, creating it if this is the
     /// first save on this device.
     ///
@@ -218,32 +246,43 @@ impl Core {
         Ok(uid)
     }
 
-    /// Download and parse this device's profile, if there is one.
+    /// Download and parse the profiles of every computer that syncs this
+    /// device.
     ///
-    /// Looks in `.proton-drive-linux/` first and falls back to the device root,
-    /// where clients before the B78 fix wrote it. The fallback is read-only: the
-    /// next save writes to the folder, and the legacy document is left alone
-    /// rather than trashed, so an older client on another machine keeps working.
-    fn load_profile(&self, root_uid: &NodeUid) -> CoreResult<Option<Profile>> {
-        let current = match self.find_device_child_folder(root_uid, PROFILE_DIR_NAME)? {
-            Some(dir_uid) => self.find_device_child_file(&dir_uid, PROFILE_FILE_NAME)?,
-            None => None,
+    /// Reads every profile in `.proton-drive-linux/`: one per machine, and the
+    /// shared `profile.json` of clients before 3.5.0. Falls back to the device
+    /// root, where clients before the B78 fix wrote it. The fallback is
+    /// read-only: the next save writes to the folder, and the legacy document
+    /// is left alone rather than trashed, so an older client on another
+    /// machine keeps working. A profile that cannot be read is left out and
+    /// logged; the others still count.
+    fn load_profiles(&self, root_uid: &NodeUid) -> CoreResult<Vec<Profile>> {
+        let mut uids = match self.find_device_child_folder(root_uid, PROFILE_DIR_NAME)? {
+            Some(dir_uid) => self.device_child_files(&dir_uid, is_profile_file_name)?,
+            None => Vec::new(),
         };
-        let uid = match current {
-            Some(uid) => uid,
-            None => match self.find_device_child_file(root_uid, PROFILE_FILE_NAME)? {
-                Some(uid) => {
-                    info!("reading legacy profile from the device root");
-                    uid
+        if uids.is_empty() {
+            uids = self.device_child_files(root_uid, |name| name == PROFILE_FILE_NAME)?;
+            if !uids.is_empty() {
+                info!("reading legacy profile from the device root");
+            }
+        }
+        let mut profiles = Vec::new();
+        for uid in uids {
+            let mut buf: Vec<u8> = Vec::new();
+            let parsed = self
+                .rt
+                .block_on(self.drive.download_file_to(&uid, &mut buf))
+                .map_err(|e| CoreError::from_api(&e, "download profile"))
+                .and_then(|()| Profile::parse(&buf).map_err(CoreError::invalid));
+            match parsed {
+                Ok(profile) => profiles.push(profile),
+                Err(e) => {
+                    warn!(%uid, error = %e.message, "could not read a profile; leaving it out")
                 }
-                None => return Ok(None),
-            },
-        };
-        let mut buf: Vec<u8> = Vec::new();
-        self.rt
-            .block_on(self.drive.download_file_to(&uid, &mut buf))
-            .map_err(|e| CoreError::from_api(&e, "download profile"))?;
-        Profile::parse(&buf).map(Some).map_err(CoreError::invalid)
+            }
+        }
+        Ok(profiles)
     }
 
     // ---- restore ----------------------------------------
@@ -265,15 +304,16 @@ impl Core {
             CoreError::internal(format!("bad device root uid: {}", device.root_uid))
         })?;
 
-        let profile = match self.load_profile(&root_uid) {
+        let profiles = match self.load_profiles(&root_uid) {
             Ok(p) => p,
             // A missing or unreadable profile is not fatal: the remote tree
             // alone is enough to offer a restore, just with plainer defaults.
             Err(e) => {
-                warn!(error = %e.message, "could not read profile; proposing defaults");
-                None
+                warn!(error = %e.message, "could not read profiles; proposing defaults");
+                Vec::new()
             }
         };
+        let hostname = this_hostname();
 
         let uids = self
             .rt
@@ -304,11 +344,12 @@ impl Core {
             // offering it as a restorable folder would sync the bookkeeping
             // back onto the machine it describes.
             .filter(|n| n.is_folder() && !n.trashed && n.name != PROFILE_DIR_NAME)
+            // The name becomes a folder under the home folder: one with a `/`
+            // or a `..` in it would put the restore somewhere else.
+            .filter(|n| crate::remote_name_is_safe(&n.name))
             .map(|n| {
                 let uid = n.uid.to_string();
-                let saved = profile
-                    .as_ref()
-                    .and_then(|p| p.folders.iter().find(|f| f.remote_uid == uid));
+                let saved = saved_folder(&profiles, &uid, &hostname);
                 let proposed = saved
                     .map(|f| PathBuf::from(&f.local_path))
                     .filter(|p| path_is_usable_here(p))
@@ -339,7 +380,8 @@ impl Core {
         &self,
         items: &[pdfs_core::control::RestoreItem],
         device: Option<&str>,
-    ) -> CoreResult<String> {
+    ) -> CoreResult<RestoreOutcome> {
+        let _registration = super::devices::SYNC_ROOT_REGISTRATION.lock();
         if items.is_empty() {
             return Err(CoreError::invalid("nothing to restore"));
         }
@@ -349,23 +391,46 @@ impl Core {
             .sync_folder_list()
             .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
 
+        // A caller must not smuggle a My files root into a device mapping,
+        // where destructive device-only operations would otherwise be allowed.
+        let device_root = super::parse_uid(&device.root_uid)
+            .ok_or_else(|| CoreError::internal("invalid device root"))?;
+        let children = self.device_root_nodes(&device_root)?;
+        let reserved = crate::devices::sync_root_reserved();
+        let mut roots: Vec<PathBuf> = existing
+            .iter()
+            .map(|f| PathBuf::from(&f.local_path))
+            .collect();
         let mut restored = 0usize;
         let mut skipped: Vec<String> = Vec::new();
         for item in items {
-            let local = PathBuf::from(&item.local_path);
-            if !local.is_absolute() {
-                skipped.push(format!("{}: local path must be absolute", item.local_path));
+            if !children.iter().any(|node| {
+                node.uid.to_string() == item.remote_uid
+                    && node.is_folder()
+                    && !node.trashed
+                    && node.name != PROFILE_DIR_NAME
+            }) {
+                skipped.push(format!(
+                    "{}: not a folder under this device",
+                    item.local_path
+                ));
                 continue;
             }
+            // The path is proposed from the profile another machine wrote, and
+            // may hold a folder name from Drive: checked like any new root.
+            let local = match pdfs_core::syncroot::resolve(Path::new(&item.local_path)) {
+                Ok(local) => local,
+                Err(e) => {
+                    skipped.push(format!("{}: {e}", item.local_path));
+                    continue;
+                }
+            };
             if existing.iter().any(|f| f.remote_uid == item.remote_uid) {
                 skipped.push(format!("{}: already synced", item.local_path));
                 continue;
             }
-            if existing
-                .iter()
-                .any(|f| Path::new(&f.local_path) == local.as_path())
-            {
-                skipped.push(format!("{}: path already in use", item.local_path));
+            if let Some(problem) = pdfs_core::syncroot::problem(&local, &roots, &reserved) {
+                skipped.push(format!("{}: {problem}", item.local_path));
                 continue;
             }
             if let Err(e) = std::fs::create_dir_all(&local) {
@@ -379,10 +444,19 @@ impl Core {
                     continue;
                 }
             };
-            let id = self
-                .db
-                .sync_folder_add(&local.to_string_lossy(), &item.remote_uid, &device.share_id)
-                .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
+            let id = match self.db.sync_folder_add(
+                &local.to_string_lossy(),
+                &item.remote_uid,
+                &device.share_id,
+            ) {
+                Ok(id) => id,
+                Err(e) => {
+                    // The folders restored before this one still need their
+                    // watches.
+                    let _ = self.sync_tx.send(sync::SyncMsg::Rewatch);
+                    return Err(CoreError::internal(format!("db: {e:?}")));
+                }
+            };
             // `ondemand` is applied through the normal request path, which
             // mounts the FUSE session and handles the folder being busy — the
             // restore does not get its own copy of that logic.
@@ -390,16 +464,57 @@ impl Core {
                 let _ = self.request_sync_folder_mode(id, "ondemand");
             }
             let _ = self.sync_tx.send(sync::SyncMsg::Reconcile(id));
+            roots.push(local);
             restored += 1;
         }
         let _ = self.sync_tx.send(sync::SyncMsg::Rewatch);
 
-        let mut message = format!("restored {restored} folder(s)");
-        if !skipped.is_empty() {
-            message.push_str(&format!("; skipped: {}", skipped.join(", ")));
+        // The reply is gone once the app has shown it; the log keeps why.
+        for reason in &skipped {
+            info!(reason, "restore skipped a folder");
         }
         info!(restored, skipped = skipped.len(), "restore complete");
-        Ok(message)
+        Ok(RestoreOutcome { restored, skipped })
+    }
+}
+
+/// Only device backups belong in the device's cross-machine profile.
+fn profile_folders(folders: Vec<pdfs_core::db::StoredSyncFolder>) -> Vec<ProfileFolder> {
+    folders
+        .into_iter()
+        .filter(|f| f.kind == "device")
+        .map(|f| ProfileFolder {
+            remote_uid: f.remote_uid,
+            local_path: f.local_path,
+            mode: MountMode::from(f.pending_mode.unwrap_or(f.mode).as_str()),
+        })
+        .collect()
+}
+
+/// What a restore did: how many folders it attached, and why it left out the
+/// others.
+pub(crate) struct RestoreOutcome {
+    pub(crate) restored: usize,
+    pub(crate) skipped: Vec<String>,
+}
+
+impl RestoreOutcome {
+    /// The activity entry's headline.
+    pub(crate) fn summary(&self) -> String {
+        match (self.restored, self.skipped.len()) {
+            (n, 0) => format!("restored {n} folder(s)"),
+            (0, k) => format!("restored no folders; skipped {k}"),
+            (n, k) => format!("restored {n} folder(s); skipped {k}"),
+        }
+    }
+
+    /// Whether the restore did all it was asked. A skipped folder is a
+    /// failure the user has to see: the reply went out as "restoring folders"
+    /// before any work, and a restore that skipped every folder used to be
+    /// logged as a success, so nothing anywhere said that nothing would
+    /// download (`docs/BUGS.md` B269).
+    pub(crate) fn complete(&self) -> bool {
+        self.skipped.is_empty()
     }
 }
 
@@ -438,6 +553,21 @@ fn default_local_path(name: &str) -> PathBuf {
 mod tests {
     use super::*;
 
+    #[test]
+    fn attached_my_files_folders_are_not_in_the_device_profile() {
+        let dir = crate::sim::daemon::scratch("profile-folder-kinds");
+        let db = pdfs_core::db::Db::open(&dir.join("cache.db")).unwrap();
+        db.sync_folder_add("/backup", "vol~backup", "device-share")
+            .unwrap();
+        db.sync_folder_attach("/work", "vol~work", "my-files-share")
+            .unwrap();
+        let folders = profile_folders(db.sync_folder_list().unwrap());
+        assert_eq!(folders.len(), 1);
+        assert_eq!(folders[0].remote_uid, "vol~backup");
+        drop(db);
+        std::fs::remove_dir_all(dir).unwrap();
+    }
+
     #[test]
     fn foreign_home_is_not_reused() {
         assert!(!path_is_usable_here(Path::new(
@@ -482,7 +612,7 @@ mod tests {
     #[test]
     fn loading_falls_back_to_a_legacy_device_root_profile() {
         let source = include_str!("profile.rs");
-        let load = function_source(source, "fn load_profile(");
+        let load = function_source(source, "fn load_profiles(");
         assert!(load.contains("PROFILE_DIR_NAME"), "prefers the folder");
         assert!(
             load.find("PROFILE_DIR_NAME").unwrap()
@@ -491,6 +621,16 @@ mod tests {
         );
     }
 
+    /// Several computers may share a device, so each saves to a file named
+    /// after its own machine id and never to the shared `profile.json`
+    /// (B252).
+    #[test]
+    fn each_machine_saves_its_own_profile() {
+        let save = function_source(include_str!("profile.rs"), "fn save_profile(");
+        assert!(save.contains("profile_file_name(&machine_id)"));
+        assert!(!save.contains("PROFILE_FILE_NAME"));
+    }
+
     /// The profile folder is the client's own bookkeeping: neither the restore
     /// picker nor `add_sync_folder` may treat it as a user folder.
     #[test]

crates/pdfs-fuse/src/reads.rs

@@ -1070,37 +1070,121 @@ impl Core {
         offset: u64,
         size: u64,
     ) -> Result<Vec<u8>, Errno> {
-        if offset >= len || size == 0 {
-            return Ok(Vec::new());
+        let read = assemble_open_read(file, len, uid, base_size, written, offset, size, |s, n| {
+            self.read_range(uid, base_mtime, base_size, s, n, true)
+                .map(Some)
+        })?;
+        Ok(read.unwrap_or_default())
+    }
+
+    /// [`Core::serve_open_read`] from bytes already on this machine only:
+    /// `Ok(None)` the moment a range of the base would have to be downloaded.
+    ///
+    /// The dispatch loop answers a read on a write handle with this, and hands
+    /// it to a worker only when it says `None`. Fetching the base there held
+    /// every request of the mount for as long as the download took, up to the
+    /// read deadline (`docs/BUGS.md` B227).
+    #[allow(clippy::too_many_arguments)]
+    pub(super) fn serve_open_read_local(
+        &self,
+        file: &Arc<File>,
+        len: u64,
+        uid: &NodeUid,
+        base_mtime: i64,
+        base_size: u64,
+        written: &Intervals,
+        offset: u64,
+        size: u64,
+    ) -> Result<Option<Vec<u8>>, Errno> {
+        assemble_open_read(file, len, uid, base_size, written, offset, size, |s, n| {
+            Ok(self.cached_range(uid, base_mtime, base_size, s, n))
+        })
+    }
+
+    /// Bytes `[offset, offset + size)` of file `ino` as `read` would serve
+    /// them, but only from this machine: an open write handle, a queued write,
+    /// or the caches. `Ok(None)` the moment any of it would have to be
+    /// downloaded, and for a size still provisional (B100), which only the
+    /// network settles. Short or empty past the end of the file.
+    ///
+    /// `copy_file_range` answers with this and leaves anything else to the
+    /// kernel's read/write copy.
+    pub(super) fn read_local(
+        &self,
+        ino: u64,
+        offset: u64,
+        size: u64,
+    ) -> Result<Option<Vec<u8>>, Errno> {
+        let handle = self.state().active_writes.get(&ino).map(|h| {
+            (
+                h.file.clone(),
+                h.len,
+                h.uid.clone(),
+                h.base_mtime,
+                h.base_size,
+                h.written.clone(),
+            )
+        });
+        if let Some((file, len, uid, base_mtime, base_size, written)) = handle {
+            return self.serve_open_read_local(
+                &file, len, &uid, base_mtime, base_size, &written, offset, size,
+            );
         }
-        let end = offset.saturating_add(size).min(len);
-        let mut out = Vec::with_capacity((end - offset) as usize);
-        for (s, e, authored) in written.segments(offset, end) {
-            if authored {
-                let mut buf = vec![0u8; (e - s) as usize];
-                file.read_exact_at(&mut buf, s).map_err(|err| {
-                    warn!(%uid, error = %err, "scratch read failed");
-                    Errno::EIO
-                })?;
-                out.extend_from_slice(&buf);
-            } else {
-                let bend = e.min(base_size);
-                if s < bend {
-                    out.extend_from_slice(&self.read_range(
-                        uid,
-                        base_mtime,
-                        base_size,
-                        s,
-                        bend - s,
-                        true,
-                    )?);
-                }
-                // Anything past the base is a hole: zero-fill.
-                let zeros = e.saturating_sub(s.max(base_size));
-                out.resize(out.len() + zeros as usize, 0);
+        let (uid, mtime, fsize, provisional) = {
+            let st = self.state();
+            match st.entries.get(&ino) {
+                Some(e) if e.node.is_file() => (
+                    e.uid.clone(),
+                    e.node.modification_time,
+                    node_size(&e.node),
+                    matches!(
+                        &e.node.kind,
+                        NodeKind::File {
+                            claimed_size: None,
+                            ..
+                        }
+                    ),
+                ),
+                Some(_) => return Err(Errno::EISDIR),
+                None => return Err(Errno::ENOENT),
             }
+        };
+        let uid = match is_local_uid(&uid) {
+            true => self.landed_stand_in_uid(&uid).unwrap_or(uid),
+            false => uid,
+        };
+        if let Some(pending) = self.pending.lock().get(&uid).cloned() {
+            let m = &pending.meta;
+            let file = File::open(&pending.path).map_err(|e| {
+                error!(%uid, path = %pending.path.display(), error = %e, "open staged blob failed");
+                Errno::EIO
+            })?;
+            let mut written = Intervals::default();
+            for &(s, e) in &m.authored {
+                written.add(s, e);
+            }
+            return self.serve_open_read_local(
+                &Arc::new(file),
+                m.len,
+                &uid,
+                m.base_mtime,
+                m.base_size,
+                &written,
+                offset,
+                size,
+            );
         }
-        Ok(out)
+        // Created here and never written: an empty file.
+        if is_local_uid(&uid) {
+            return Ok(Some(Vec::new()));
+        }
+        if provisional {
+            return Ok(None);
+        }
+        if offset >= fsize || size == 0 {
+            return Ok(Some(Vec::new()));
+        }
+        Ok(self.cached_range(&uid, mtime, fsize, offset, size.min(fsize - offset)))
     }
 
     /// The largest amount [`Core::fill_gaps_cached`] will copy out of the local
@@ -1242,6 +1326,49 @@ impl Core {
     }
 }
 
+/// The bytes `[offset, offset + size)` of a file open for writing: authored
+/// ranges from its scratch `file`, the rest from its base through `base`,
+/// and zeros past the base. `Ok(None)` when `base` says it cannot answer.
+#[allow(clippy::too_many_arguments)]
+fn assemble_open_read(
+    file: &File,
+    len: u64,
+    uid: &NodeUid,
+    base_size: u64,
+    written: &Intervals,
+    offset: u64,
+    size: u64,
+    mut base: impl FnMut(u64, u64) -> Result<Option<Vec<u8>>, Errno>,
+) -> Result<Option<Vec<u8>>, Errno> {
+    if offset >= len || size == 0 {
+        return Ok(Some(Vec::new()));
+    }
+    let end = offset.saturating_add(size).min(len);
+    let mut out = Vec::with_capacity((end - offset) as usize);
+    for (s, e, authored) in written.segments(offset, end) {
+        if authored {
+            let mut buf = vec![0u8; (e - s) as usize];
+            file.read_exact_at(&mut buf, s).map_err(|err| {
+                warn!(%uid, error = %err, "scratch read failed");
+                Errno::EIO
+            })?;
+            out.extend_from_slice(&buf);
+        } else {
+            let bend = e.min(base_size);
+            if s < bend {
+                match base(s, bend - s)? {
+                    Some(bytes) => out.extend_from_slice(&bytes),
+                    None => return Ok(None),
+                }
+            }
+            // Anything past the base is a hole: zero-fill.
+            let zeros = e.saturating_sub(s.max(base_size));
+            out.resize(out.len() + zeros as usize, 0);
+        }
+    }
+    Ok(Some(out))
+}
+
 #[cfg(test)]
 mod block_ring_tests {
     use super::*;
@@ -1394,3 +1521,54 @@ mod prefetch_tests {
         assert!(prefetch.streams.lock().len() <= MAX_PREFETCH_STREAMS + 1);
     }
 }
+
+#[cfg(test)]
+mod open_read_tests {
+    use super::*;
+    use proton_drive_rs::proton_sdk::ids::{LinkId, VolumeId};
+
+    fn scratch(bytes: &[u8]) -> (File, PathBuf) {
+        let path = std::env::temp_dir().join(format!(
+            "pdfs-open-read-{}-{}",
+            std::process::id(),
+            std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .unwrap()
+                .as_nanos()
+        ));
+        let mut file = File::options()
+            .create_new(true)
+            .read(true)
+            .write(true)
+            .open(&path)
+            .unwrap();
+        file.write_all(bytes).unwrap();
+        (file, path)
+    }
+
+    /// The dispatch loop answers from what is on this machine and says so
+    /// when the base would have to be downloaded, for a worker to do it
+    /// (`docs/BUGS.md` B227).
+    #[test]
+    fn a_read_needing_the_base_says_so_instead_of_fetching() {
+        let uid = NodeUid::new(VolumeId::from("v"), LinkId::from("f"));
+        let (file, path) = scratch(b"ABCDEFGH");
+        let mut written = Intervals::default();
+        written.add(0, 4);
+
+        let authored = assemble_open_read(&file, 8, &uid, 8, &written, 0, 4, |_, _| {
+            panic!("an authored range never asks the base")
+        });
+        assert_eq!(authored.unwrap().as_deref(), Some(&b"ABCD"[..]));
+
+        let missing = assemble_open_read(&file, 8, &uid, 8, &written, 2, 6, |_, _| Ok(None));
+        assert_eq!(missing.unwrap(), None);
+
+        let base = assemble_open_read(&file, 10, &uid, 8, &written, 2, 8, |s, n| {
+            assert_eq!((s, n), (4, 4));
+            Ok(Some(b"efgh".to_vec()))
+        });
+        assert_eq!(base.unwrap().as_deref(), Some(&b"CDefgh\0\0"[..]));
+        let _ = std::fs::remove_file(path);
+    }
+}

crates/pdfs-fuse/src/redate.rs

@@ -190,6 +190,7 @@ impl Core {
             .map_err(|e| CoreError::internal(format!("stat {}: {e}", path.display())))?
             .len();
         let media_type = media_type_of(&candidate.name).unwrap_or("application/octet-stream");
+        let thumbnails = self.upload_thumbnails(&path, &candidate.name);
 
         let guard =
             self.transfers
@@ -199,6 +200,7 @@ impl Core {
         let reader = CountingReader::new(std::io::BufReader::new(file), &guard);
         let metadata = PhotoUploadMetadata {
             capture_time: Some(candidate.wanted),
+            last_modification_time: pdfs_core::timestamp::modification_time(candidate.wanted),
             ..Default::default()
         };
         let uploaded = self.rt.block_on(photos.upload_photo_from(
@@ -206,7 +208,7 @@ impl Core {
             media_type,
             reader,
             size as i64,
-            Vec::new(),
+            thumbnails,
             metadata,
             false,
         ));
@@ -291,7 +293,14 @@ impl Core {
             let mut state = REDATE.lock();
             state.running = false;
             state.cancel = None;
-            state.last = outcome.as_ref().ok().cloned();
+            state.last = Some(match &outcome {
+                Ok(summary) => summary.clone(),
+                Err(e) => RedateSummary {
+                    error: Some(e.to_string()),
+                    dry_run,
+                    ..Default::default()
+                },
+            });
             match &outcome {
                 Ok(summary) => info!(
                     candidates = summary.candidates,

crates/pdfs-fuse/src/relocate.rs

@@ -25,6 +25,7 @@ use proton_drive_rs::NodeKind;
 use proton_drive_rs::proton_sdk::ids::NodeUid;
 use tracing::{info, warn};
 
+use super::state::State;
 use super::sync::mirror_subtree_unsynced;
 use super::{Core, is_local_uid, parse_uid};
 
@@ -130,6 +131,24 @@ fn rename_noreplace(from: &Path, to: &Path) -> std::io::Result<()> {
     }
 }
 
+/// Whether inode `ino` is `root` or lies under it in the tree. Bounded, so a
+/// parent cycle in corrupt data cannot hang the caller.
+pub(crate) fn ino_is_under(st: &State, mut ino: u64, root: u64) -> bool {
+    for _ in 0..MAX_TREE_DEPTH {
+        if ino == root {
+            return true;
+        }
+        match st.entries.get(&ino) {
+            Some(entry) if entry.parent != ino => ino = entry.parent,
+            _ => return false,
+        }
+    }
+    false
+}
+
+/// How deep [`ino_is_under`] walks before it gives up.
+const MAX_TREE_DEPTH: usize = 1024;
+
 /// Whether `uid` is `root` or lies under it, as far as the nodes table knows.
 fn under(core: &Core, root: &NodeUid, uid: &str) -> bool {
     let root = root.to_string();
@@ -336,7 +355,7 @@ impl Core {
                     core.require_uid_writable(authority)
                         .map_err(|e| core.errno_error(e, "move access"))?;
                 }
-                if self.has_pending_work_under(&uid)? {
+                if self.has_pending_work_under(ino, &uid)? {
                     return Err(CoreError::conflict(
                         "it has changes that are not uploaded yet; wait for the upload to finish",
                     ));
@@ -410,10 +429,11 @@ impl Core {
         Ok(uid)
     }
 
-    /// Whether the queue owes Drive anything for `uid` or a node under it, or a
-    /// file under it is open for writing. Moving such a node away would strand
-    /// the pending change against a path that no longer leads to it.
-    fn has_pending_work_under(&self, uid: &NodeUid) -> CoreResult<bool> {
+    /// Whether the queue owes Drive anything for `uid` (inode `ino`) or a node
+    /// under it, or a file under it is open for writing. Moving such a node away
+    /// would strand the pending change against a path that no longer leads to
+    /// it.
+    fn has_pending_work_under(&self, ino: u64, uid: &NodeUid) -> CoreResult<bool> {
         let ops = self
             .db
             .pending_ops()
@@ -427,12 +447,19 @@ impl Core {
         }) {
             return Ok(true);
         }
-        // Collected first so no State lock is held across the nodes-table reads.
-        let mut writing = Vec::new();
+        // Open handles are placed in the tree by inode, not by uid in the nodes
+        // table. A file opened just after its create landed holds the
+        // placeholder uid until the tree catches up, and the nodes table no
+        // longer has that uid, so the move went ahead under an open write.
+        let mut writing = false;
         self.for_each_state(|st| {
-            writing.extend(st.active_writes.values().map(|w| w.uid.to_string()));
+            writing = st
+                .active_writes
+                .keys()
+                .chain(&st.releasing)
+                .any(|&open| ino_is_under(st, open, ino));
         });
-        Ok(writing.iter().any(|w| under(self, uid, w)))
+        Ok(writing)
     }
 
     /// Bring the source location level with a move Drive has made.
@@ -528,6 +555,7 @@ mod tests {
 
     fn folder(id: i64, local_path: &str, mode: &str) -> StoredSyncFolder {
         StoredSyncFolder {
+            kind: "device".into(),
             id,
             local_path: local_path.to_string(),
             remote_uid: format!("vol~root{id}"),

crates/pdfs-fuse/src/revisions.rs

@@ -111,6 +111,11 @@ impl Core {
         // stale from here on, and the server may not have applied the swap yet.
         self.cache.evict(uid);
         self.evict_reader(uid);
+        // A file kept offline gets the restored content back on disk, and
+        // again when the event of the swap arrives (`docs/BUGS.md` B282).
+        if self.cache.is_pinned(uid) {
+            self.recheck_pinned(uid);
+        }
         self.log_activity(
             ActivityKind::Restore,
             name,

crates/pdfs-fuse/src/sharing.rs

@@ -9,7 +9,8 @@
 use std::path::Path;
 
 use pdfs_core::control::{
-    BookmarkInfo, DirEntry, InvitationInfo, PublicLinkInfo, ShareEntry, ShareEntryKind, SharedItem,
+    BookmarkInfo, DirEntry, InvitationInfo, LinkChange, PublicLinkInfo, ShareEntry, ShareEntryKind,
+    SharedItem,
 };
 use pdfs_core::{CoreError, CoreResult};
 use tracing::debug;
@@ -66,6 +67,7 @@ fn shared_entry_of(core: &Core, n: Node) -> DirEntry {
         size,
         modified: n.modification_time,
         pinned: false,
+        pinned_by_folder: false,
         cached: false,
         path: core.rel_path_for_uid(&n.uid).unwrap_or_default(),
         uid: n.uid.to_string(),
@@ -103,7 +105,7 @@ impl Core {
         role: &str,
         message: Option<&str>,
     ) -> CoreResult<(usize, usize)> {
-        let uid = self.resolve_anywhere(uid)?;
+        let uid = self.resolve_shareable(uid)?;
         self.share_node_for_uid(&uid, emails, role, message)
     }
 
@@ -136,7 +138,7 @@ impl Core {
         &self,
         uid: &str,
     ) -> CoreResult<(Vec<ShareEntry>, Option<PublicLinkInfo>)> {
-        let uid = self.resolve_anywhere(uid)?;
+        let uid = self.resolve_shareable(uid)?;
         self.list_share_for_uid(&uid)
     }
 
@@ -213,7 +215,7 @@ impl Core {
         kind: ShareEntryKind,
         role: &str,
     ) -> CoreResult<()> {
-        let uid = self.resolve_anywhere(uid)?;
+        let uid = self.resolve_shareable(uid)?;
         self.update_share_role_for_uid(&uid, id, kind, role)
     }
 
@@ -276,7 +278,7 @@ impl Core {
         id: &str,
         kind: ShareEntryKind,
     ) -> CoreResult<()> {
-        let uid = self.resolve_anywhere(uid)?;
+        let uid = self.resolve_shareable(uid)?;
         self.remove_share_entry_for_uid(&uid, id, kind)
     }
 
@@ -347,7 +349,7 @@ impl Core {
         password: Option<&str>,
         expires: Option<i64>,
     ) -> CoreResult<PublicLinkInfo> {
-        let uid = self.resolve_anywhere(uid)?;
+        let uid = self.resolve_shareable(uid)?;
         self.create_public_link_for_uid(&uid, role, password, expires)
     }
 
@@ -366,6 +368,89 @@ impl Core {
         Ok(public_link_info(link))
     }
 
+    /// Change the public link `id` on the node at `rel`, keeping its URL.
+    pub(crate) fn update_public_link(
+        &self,
+        rel: &Path,
+        id: &str,
+        role: Option<&str>,
+        password: LinkChange<String>,
+        expires: LinkChange<i64>,
+    ) -> CoreResult<PublicLinkInfo> {
+        let (_ino, uid) = self.resolve(rel)?;
+        self.update_public_link_for_uid(&uid, id, role, password, expires)
+    }
+
+    /// [`Core::update_public_link`] for a node addressed through any daemon
+    /// location.
+    pub(crate) fn update_public_link_by_uid(
+        &self,
+        uid: &str,
+        id: &str,
+        role: Option<&str>,
+        password: LinkChange<String>,
+        expires: LinkChange<i64>,
+    ) -> CoreResult<PublicLinkInfo> {
+        let uid = self.resolve_shareable(uid)?;
+        self.update_public_link_for_uid(&uid, id, role, password, expires)
+    }
+
+    /// The SDK sets all three options on every update, so each `Keep` is
+    /// filled in from the link as it stands.
+    fn update_public_link_for_uid(
+        &self,
+        uid: &NodeUid,
+        id: &str,
+        role: Option<&str>,
+        password: LinkChange<String>,
+        expires: LinkChange<i64>,
+    ) -> CoreResult<PublicLinkInfo> {
+        let link = self
+            .rt
+            .block_on(self.client.get_public_link(uid))
+            .map_err(|e| CoreError::from_api(&e, "get public link"))?
+            .filter(|l| l.public_link_id == id)
+            .ok_or_else(|| CoreError::not_found("public link not found"))?;
+        let role = match role {
+            Some(role) => role_from_str(role)?,
+            None => link.role,
+        };
+        let unchanged = role == link.role
+            && matches!(password, LinkChange::Keep)
+            && matches!(expires, LinkChange::Keep);
+        if unchanged {
+            return Ok(public_link_info(link));
+        }
+        let password = match password {
+            LinkChange::Keep if link.has_custom_password => {
+                // Sending `None` here would quietly remove the password.
+                Some(link.custom_password.clone().ok_or_else(|| {
+                    CoreError::conflict(
+                        "the link's password could not be read; set a new one or remove it",
+                    )
+                })?)
+            }
+            LinkChange::Keep | LinkChange::Remove => None,
+            LinkChange::Set(password) if password.is_empty() => {
+                return Err(CoreError::invalid("the new password is empty"));
+            }
+            LinkChange::Set(password) => Some(password),
+        };
+        let expires = match expires {
+            LinkChange::Keep => link.expiration_time,
+            LinkChange::Remove => None,
+            LinkChange::Set(at) => Some(at),
+        };
+        let link = self
+            .rt
+            .block_on(
+                self.client
+                    .update_public_link(uid, role, password.as_deref(), expires),
+            )
+            .map_err(|e| CoreError::from_api(&e, "update public link"))?;
+        Ok(public_link_info(link))
+    }
+
     /// Remove the public link `id` from the node at `rel`.
     pub(crate) fn remove_public_link(&self, rel: &Path, id: &str) -> CoreResult<()> {
         let (_ino, uid) = self.resolve(rel)?;
@@ -375,7 +460,7 @@ impl Core {
     /// [`Core::remove_public_link`] for a node addressed through any daemon
     /// location.
     pub(crate) fn remove_public_link_by_uid(&self, uid: &str, id: &str) -> CoreResult<()> {
-        let uid = self.resolve_anywhere(uid)?;
+        let uid = self.resolve_shareable(uid)?;
         self.remove_public_link_for_uid(&uid, id)
     }
 
@@ -401,7 +486,7 @@ impl Core {
 
     /// [`Core::stop_sharing`] for a node addressed through any daemon location.
     pub(crate) fn stop_sharing_by_uid(&self, uid: &str) -> CoreResult<StopSharingOutcome> {
-        let uid = self.resolve_anywhere(uid)?;
+        let uid = self.resolve_shareable(uid)?;
         self.stop_sharing_for_uid(&uid)
     }
 

crates/pdfs-fuse/src/sim/fake_drive.rs

@@ -31,6 +31,9 @@
 //! - **A full account** ([`FakeDrive::set_quota`]) refusing uploads with
 //!   `InsufficientQuota`.
 //!
+//! It also holds the account's computers, each with a root folder outside My
+//! files, so a simulated daemon can register its own and sync a local folder.
+//!
 //! A test can also hold the next read of one node on its way to Drive
 //! ([`FakeClient::hold_next_read`]), to make a change while the daemon waits
 //! for the answer, or on its way back ([`FakeClient::hold_answer_to_next_read`]),
@@ -54,9 +57,12 @@ use parking_lot::Mutex;
 use proton_drive_rs::proton_sdk::account::Quota;
 use proton_drive_rs::proton_sdk::api::ResponseCode;
 use proton_drive_rs::proton_sdk::error::{ProtonApiError, ProtonError, Result};
-use proton_drive_rs::proton_sdk::ids::{DriveEventId, LinkId, NodeUid, VolumeId};
+use proton_drive_rs::proton_sdk::ids::{
+    DeviceUid, DriveEventId, LinkId, NodeUid, ShareId, VolumeId,
+};
 use proton_drive_rs::{
-    DriveEvent, DriveEventScopeId, Node, NodeKind, NodeMoveItem, RevisionState, Thumbnail,
+    AvailableNameTarget, Device as Computer, DeviceType, DriveEvent, DriveEventScopeId, Node,
+    NodeKind, NodeMoveItem, RevisionState, Thumbnail, ThumbnailType,
 };
 use sha1::{Digest as _, Sha1};
 
@@ -111,6 +117,9 @@ struct Server {
     block_pattern: Vec<u64>,
     /// The account's storage limit in bytes.
     max_space: i64,
+    /// The account's computers, oldest first, as `(name, type, root folder)`.
+    /// [`Computer`] is not `Clone`, so each answer builds them afresh.
+    devices: Vec<(String, DeviceType, NodeUid)>,
 }
 
 impl Server {
@@ -162,6 +171,53 @@ impl Server {
         false
     }
 
+    /// The `n`th computer of the account, as Drive lists it.
+    fn computer(&self, n: usize) -> Computer {
+        let (name, device_type, root) = &self.devices[n];
+        Computer {
+            uid: DeviceUid::new(format!("device{}", n + 1)),
+            device_type: *device_type,
+            name: Ok(name.clone()),
+            root_folder_uid: root.clone(),
+            creation_time: self.current(root).map_or(0, |remote| remote.created),
+            last_sync_time: None,
+            share_id: ShareId::new(format!("device-share{}", n + 1)),
+        }
+    }
+
+    /// Copy `uid` and, for a folder, everything live below it under `parent` as
+    /// `name`, the way Drive's copy endpoint does. Returns the copy's uid.
+    fn copy_subtree(&mut self, uid: &NodeUid, parent: &NodeUid, name: String) -> NodeUid {
+        let source = self
+            .current(uid)
+            .cloned()
+            .expect("the caller checked the source");
+        let copy = self.mint_uid();
+        let now = now_secs();
+        self.put(
+            &copy,
+            Some(Remote {
+                parent: Some(parent.clone()),
+                name,
+                created: now,
+                ..source
+            }),
+        );
+        let children: Vec<(NodeUid, String)> = self
+            .nodes
+            .keys()
+            .filter_map(|child| {
+                let remote = self.current(child)?;
+                (remote.parent.as_ref() == Some(uid) && !remote.trashed)
+                    .then(|| (child.clone(), remote.name.clone()))
+            })
+            .collect();
+        for (child, child_name) in children {
+            self.copy_subtree(&child, &copy, child_name);
+        }
+        copy
+    }
+
     fn mint_uid(&mut self) -> NodeUid {
         self.next_link += 1;
         uid(&format!("L{}", self.next_link))
@@ -305,6 +361,7 @@ impl FakeDrive {
             events: Vec::new(),
             block_pattern: vec![pdfs_core::cache::BLOCK_SIZE],
             max_space: 1 << 40,
+            devices: Vec::new(),
         };
         let now = now_secs();
         server.nodes.insert(
@@ -338,6 +395,10 @@ impl FakeDrive {
             hold: Mutex::new(None),
             hold_answer: Mutex::new(None),
             hold_trash: Mutex::new(None),
+            hold_download: Mutex::new(None),
+            thumbnails: Mutex::new(HashMap::new()),
+            content_read: AtomicU64::new(0),
+            hold_any_landing: AtomicBool::new(false),
             hold_landing: Mutex::new(None),
             drop_after_create: AtomicBool::new(false),
             lose_create_reply: AtomicBool::new(false),
@@ -616,8 +677,17 @@ struct ClientInner {
     hold_answer: Mutex<Option<Arc<HoldState>>>,
     /// The trash [`FakeClient::hold_next_trash`] is waiting for.
     hold_trash: Mutex<Option<Arc<HoldState>>>,
+    /// The download [`FakeClient::hold_next_download`] is waiting for.
+    hold_download: Mutex<Option<Arc<HoldState>>>,
+    /// Thumbnails set by [`FakeClient::set_thumbnail`].
+    thumbnails: Mutex<HashMap<NodeUid, Vec<u8>>>,
+    /// File content bytes served, by downloads and ranged reads alike.
+    content_read: AtomicU64,
     /// The landing [`FakeClient::hold_next_landing`] is waiting for.
     hold_landing: Mutex<Option<Arc<HoldState>>>,
+    /// Set by [`FakeClient::hold_next_landing_of_any`]: hold whichever node
+    /// lands next.
+    hold_any_landing: AtomicBool,
     /// Set by [`FakeClient::drop_link_after_next_create`].
     drop_after_create: AtomicBool,
     /// Set by [`FakeClient::lose_reply_to_next_create`].
@@ -755,6 +825,28 @@ impl FakeClient {
         Held(state)
     }
 
+    /// Hold the next download of `uid`'s content once Drive has answered it,
+    /// before the bytes reach the daemon, until the answer is dropped.
+    /// Give `uid` a server thumbnail, as an upload that carried one would.
+    pub(crate) fn set_thumbnail(&self, uid: &NodeUid, bytes: Vec<u8>) {
+        self.0.thumbnails.lock().insert(uid.clone(), bytes);
+    }
+
+    /// File content bytes served so far, by whole downloads and ranged reads.
+    pub(crate) fn content_read(&self) -> u64 {
+        self.0.content_read.load(Ordering::SeqCst)
+    }
+
+    pub(crate) fn hold_next_download(&self, uid: &NodeUid) -> Held {
+        let state = Arc::new(HoldState {
+            uid: uid.clone(),
+            reached: AtomicBool::new(false),
+            released: AtomicBool::new(false),
+        });
+        *self.0.hold_download.lock() = Some(state.clone());
+        Held(state)
+    }
+
     /// Hold the drain once the next upload to `uid` has landed and its blob
     /// is let go of, before the tree has the node (`DriveApi::landing`), until
     /// the answer is dropped.
@@ -768,6 +860,14 @@ impl FakeClient {
         Held(state)
     }
 
+    /// [`FakeClient::hold_next_landing`] for whichever node lands next, such
+    /// as a new file, whose uid Drive has not minted yet.
+    pub(crate) fn hold_next_landing_of_any(&self) -> Held {
+        let held = self.hold_next_landing(&uid("*"));
+        self.0.hold_any_landing.store(true, Ordering::SeqCst);
+        held
+    }
+
     /// Make the next file create on Drive, then hold its answer until the
     /// answer is dropped, as a slow link does.
     pub(crate) fn hold_reply_to_next_create(&self) -> Held {
@@ -1039,6 +1139,14 @@ fn delete_one(server: &mut Server, uid: &NodeUid) -> Result<()> {
 
 #[async_trait]
 impl DriveApi for FakeClient {
+    async fn context_share_id(&self, uid: &NodeUid) -> Result<ShareId> {
+        self.request(false, |server| {
+            assert_eq!(uid, &server.root);
+            Ok(ShareId::new("my-files-share"))
+        })
+        .await
+    }
+
     async fn get_my_files_folder(&self) -> Result<Node> {
         self.request(false, |server| {
             let root = server.root.clone();
@@ -1383,6 +1491,21 @@ impl DriveApi for FakeClient {
         }))
     }
 
+    async fn download_thumbnail(
+        &self,
+        uid: &NodeUid,
+        _thumbnail_type: ThumbnailType,
+    ) -> Result<Option<Vec<u8>>> {
+        self.request(false, |server| {
+            server
+                .current(uid)
+                .map(|_| ())
+                .ok_or_else(|| api(ResponseCode::DoesNotExist, "file not found"))
+        })
+        .await?;
+        Ok(self.0.thumbnails.lock().get(uid).cloned())
+    }
+
     async fn download_file_to_dyn(
         &self,
         uid: &NodeUid,
@@ -1396,6 +1519,11 @@ impl DriveApi for FakeClient {
                     .ok_or_else(|| api(ResponseCode::DoesNotExist, "file not found"))
             })
             .await?;
+        self.wait_if_held(&self.0.hold_download, std::slice::from_ref(uid))
+            .await;
+        self.0
+            .content_read
+            .fetch_add(content.len() as u64, Ordering::SeqCst);
         output.write_all(&content).map_err(io_error)
     }
 
@@ -1437,6 +1565,61 @@ impl DriveApi for FakeClient {
         .await
     }
 
+    async fn copy_node(
+        &self,
+        uid: &NodeUid,
+        new_parent: &NodeUid,
+        name: Option<&str>,
+    ) -> Result<NodeUid> {
+        self.request(true, |server| {
+            if !server.is_folder(new_parent) {
+                return Err(api(ResponseCode::DoesNotExist, "parent folder not found"));
+            }
+            let source = server
+                .current(uid)
+                .filter(|remote| !remote.trashed)
+                .cloned()
+                .ok_or_else(|| api(ResponseCode::DoesNotExist, "node not found"))?;
+            if server.is_below(new_parent, uid) {
+                return Err(api(
+                    ResponseCode::InvalidRequirements,
+                    "cannot copy a folder into itself",
+                ));
+            }
+            let name = name.map_or(source.name.clone(), str::to_owned);
+            if server.live_child_named(new_parent, &name).is_some() {
+                return Err(api(
+                    ResponseCode::AlreadyExists,
+                    "a file or folder with that name already exists",
+                ));
+            }
+            Ok(server.copy_subtree(uid, new_parent, name))
+        })
+        .await
+    }
+
+    async fn get_available_name(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        target: AvailableNameTarget,
+    ) -> Result<String> {
+        self.request(false, |server| {
+            let (stem, extension) = match (target, name.rsplit_once('.')) {
+                (AvailableNameTarget::File, Some((stem, ext))) if !stem.is_empty() => {
+                    (stem, format!(".{ext}"))
+                }
+                _ => (name, String::new()),
+            };
+            let free = std::iter::once(name.to_owned())
+                .chain((1..).map(|n| format!("{stem} ({n}){extension}")))
+                .find(|candidate| server.live_child_named(parent_uid, candidate).is_none())
+                .expect("an unbounded sequence has a free name");
+            Ok(free)
+        })
+        .await
+    }
+
     fn move_nodes_streaming<'a>(
         &'a self,
         items: Vec<NodeMoveItem>,
@@ -1484,8 +1667,12 @@ impl DriveApi for FakeClient {
     fn landing(&self, uid: &NodeUid) {
         let state = {
             let mut hold = self.0.hold_landing.lock();
+            let any = self.0.hold_any_landing.load(Ordering::SeqCst);
             match hold.as_ref() {
-                Some(state) if state.uid == *uid => hold.take(),
+                Some(state) if any || state.uid == *uid => {
+                    self.0.hold_any_landing.store(false, Ordering::SeqCst);
+                    hold.take()
+                }
                 _ => None,
             }
         };
@@ -1506,6 +1693,42 @@ impl DriveApi for FakeClient {
         .await
     }
 
+    async fn enumerate_devices(&self) -> Result<Vec<Computer>> {
+        self.request(false, |server| {
+            Ok((0..server.devices.len())
+                .map(|n| server.computer(n))
+                .collect())
+        })
+        .await
+    }
+
+    async fn create_device(&self, name: &str, device_type: DeviceType) -> Result<Computer> {
+        self.request(true, |server| {
+            // A device root has no parent: like on Drive, it is not in My files.
+            // It is listed at once, as the My files root is: the listing lag is
+            // about children appearing, and the daemon lists the new root next.
+            let root = server.mint_uid();
+            let now = now_secs();
+            server.nodes.insert(
+                root.clone(),
+                vec![(
+                    Instant::now() - HISTORY,
+                    Some(Remote {
+                        parent: None,
+                        name: name.to_owned(),
+                        trashed: false,
+                        created: now,
+                        modified: now,
+                        file: None,
+                    }),
+                )],
+            );
+            server.devices.push((name.to_owned(), device_type, root));
+            Ok(server.computer(server.devices.len() - 1))
+        })
+        .await
+    }
+
     async fn enumerate_trash_node_uids(&self) -> Result<Vec<NodeUid>> {
         self.request(false, |server| {
             Ok(server
@@ -1544,13 +1767,19 @@ impl RevisionRead for FakeRevision {
 
     async fn read_at(&self, offset: u64, length: u64) -> Result<Vec<u8>> {
         let content = self.content.clone();
-        self.client
+        let read = self
+            .client
             .request(false, move |_| {
                 let start = (offset as usize).min(content.len());
                 let end = (offset.saturating_add(length) as usize).min(content.len());
                 Ok(content[start..end].to_vec())
             })
-            .await
+            .await?;
+        self.client
+            .0
+            .content_read
+            .fetch_add(read.len() as u64, Ordering::SeqCst);
+        Ok(read)
     }
 }
 

crates/pdfs-fuse/src/state.rs

@@ -212,6 +212,31 @@ pub(crate) fn lid_ino(lid: i64) -> u64 {
     lid.unsigned_abs() + crate::ROOT_INO
 }
 
+/// The inodes of the stored nodes among `nodes`, from their local ids, for
+/// [`State::intern_batch_with_inos`]. Called before the state lock is taken;
+/// a node that already has a row keeps its id. Empty when the database fails,
+/// which leaves the allocation to the lock holder, as before.
+pub(crate) fn inos_for(db: &Db, nodes: &[Node]) -> HashMap<NodeUid, u64> {
+    let stored: Vec<&Node> = nodes
+        .iter()
+        .filter(|node| !crate::r#virtual::is_virtual_uid(&node.uid))
+        .collect();
+    if stored.is_empty() {
+        return HashMap::new();
+    }
+    match db.lids_for(&stored) {
+        Ok(lids) => stored
+            .iter()
+            .zip(lids)
+            .map(|(node, lid)| (node.uid.clone(), lid_ino(lid)))
+            .collect(),
+        Err(error) => {
+            warn!(%error, "no local ids before the listing; allocating them under the lock");
+            HashMap::new()
+        }
+    }
+}
+
 /// The local id of the node at inode `ino`, the inverse of [`lid_ino`]:
 /// `None` for the root and a fallback inode.
 pub(crate) fn ino_lid(ino: u64) -> Option<i64> {
@@ -241,6 +266,11 @@ pub(crate) struct State {
     pub(crate) next_ino: u64,
     /// Shared write state keyed by inode. Concurrent writers share the scratch file.
     pub(crate) active_writes: HashMap<u64, WriteHandle>,
+    /// Inodes whose last write handle `release` has taken out of
+    /// [`State::active_writes`] and is still queueing. `close(2)` returns
+    /// before that, and in between the edit is in neither the handles nor the
+    /// queue, so a check for changes not on Drive yet looks here too.
+    pub(crate) releasing: HashSet<u64>,
     /// Maps file handle id (fh) to inode (ino). Read-only opens use fh 0 and
     /// have no entry here.
     pub(crate) handles: HashMap<u64, u64>,
@@ -403,6 +433,7 @@ impl State {
             roots: HashSet::new(),
             next_ino: FALLBACK_INO,
             active_writes: HashMap::new(),
+            releasing: HashSet::new(),
             handles: HashMap::new(),
             next_fh: 1,
             dir_snapshots: HashMap::new(),
@@ -1074,20 +1105,34 @@ impl State {
     ///
     /// This is what keeps `ls` on a large folder quick: one commit for the
     /// listing, rather than one autocommit — and one fsync — per child.
-    pub(crate) fn intern_batch(&mut self, parent: u64, mut nodes: Vec<Node>) -> Vec<u64> {
+    #[cfg(test)]
+    pub(crate) fn intern_batch(&mut self, parent: u64, nodes: Vec<Node>) -> Vec<u64> {
+        self.intern_batch_with_inos(parent, nodes, HashMap::new())
+    }
+
+    /// [`State::intern_batch`], with inodes for new entries that the caller
+    /// allocated before it took the lock, from [`inos_for`]. Allocating them
+    /// is a write transaction, and under the lock every inline handler of
+    /// every mount waited for it (`docs/BUGS.md` B221). A node missing from
+    /// `inos` still gets one here.
+    pub(crate) fn intern_batch_with_inos(
+        &mut self,
+        parent: u64,
+        mut nodes: Vec<Node>,
+        mut inos: HashMap<NodeUid, u64>,
+    ) -> Vec<u64> {
         for node in &mut nodes {
             self.keep_revision_mtime(node);
         }
         self.outbox.push(DbWrite::Upsert(nodes.clone()));
         let fresh: Vec<&Node> = nodes
             .iter()
-            .filter(|node| !self.by_uid.contains_key(&node.uid))
+            .filter(|node| !self.by_uid.contains_key(&node.uid) && !inos.contains_key(&node.uid))
             .collect();
-        let mut inos = if fresh.is_empty() {
-            HashMap::new()
-        } else {
-            self.new_inos(&fresh)
-        };
+        if !fresh.is_empty() {
+            let allocated = self.new_inos(&fresh);
+            inos.extend(allocated);
+        }
         nodes
             .into_iter()
             .map(|node| {
@@ -1098,6 +1143,13 @@ impl State {
             .collect()
     }
 
+    /// Record `uid`'s listing as complete once the lock is released, after the
+    /// rows of its children: written the other way round, a crash between the
+    /// two left a folder marked complete with no children to show.
+    pub(crate) fn record_listed(&mut self, uid: NodeUid) {
+        self.outbox.push(DbWrite::SetListed(uid, true));
+    }
+
     /// Check if a directory inode has any child nodes in memory or in the database.
     pub(crate) fn has_children(&self, parent: u64) -> bool {
         // A resident listing is authoritative even when empty. Falling through
@@ -1467,6 +1519,44 @@ mod tests {
         );
     }
 
+    /// A listing's inodes are allocated before the lock is taken, and are the
+    /// ones a node would get under it (`docs/BUGS.md` B221).
+    #[test]
+    fn inodes_allocated_before_the_lock_are_the_ones_the_node_keeps() {
+        let (mut st, _dir) = state();
+        let db = st.db.clone();
+        let listing = vec![
+            node("a", "root", "a.txt", false),
+            node("b", "root", "b.txt", false),
+        ];
+        let early = inos_for(&db, &listing);
+        assert_eq!(early.len(), 2);
+        let inos = st.intern_batch_with_inos(0, listing, early.clone());
+        assert_eq!(inos, [early[&uid("a")], early[&uid("b")]]);
+        st.flush_outbox();
+
+        let mut restarted = State::new(db, HashMap::new());
+        assert_eq!(
+            restarted.intern(0, node("b", "root", "b.txt", false)),
+            early[&uid("b")]
+        );
+    }
+
+    /// The listing is recorded complete with its children's rows, when the
+    /// lock goes, never ahead of them.
+    #[test]
+    fn a_listing_is_recorded_complete_after_its_children() {
+        let (mut st, _dir) = state();
+        let root = st.intern(0, node("root", "none", "root", true));
+        st.flush_outbox();
+        st.intern_batch(root, vec![node("a", "root", "a.txt", false)]);
+        st.record_listed(uid("root"));
+        assert!(st.db.children_if_listed(&uid("root")).unwrap().is_none());
+        st.flush_outbox();
+        let kids = st.db.children_if_listed(&uid("root")).unwrap().unwrap();
+        assert_eq!(kids.len(), 1);
+    }
+
     /// Audit A5. Moving a file out of a folder leaves that folder's DB row
     /// claiming a complete listing, so once the hot cache drops it, remote
     /// changes under it stop being seen. `relocate` has to clear both sides.

crates/pdfs-fuse/src/supervisor.rs

@@ -36,6 +36,11 @@ const TICK: Duration = Duration::from_secs(15);
 /// would train everyone to ignore the real one.
 const STALL_AFTER: Duration = Duration::from_secs(120);
 
+/// How long a sync pass may go without reporting progress before it is called
+/// out. Much longer than [`STALL_AFTER`]: one large file in a pass reports
+/// nothing until its whole transfer is done.
+const SYNC_STALL_AFTER: Duration = Duration::from_secs(900);
+
 /// How often resident size goes into the log.
 const RSS_EVERY: Duration = Duration::from_secs(300);
 
@@ -52,7 +57,10 @@ pub(crate) fn run(core: Core, control_socket: PathBuf) {
     }
 
     let mut last_rss = Instant::now();
-    let mut last_ping = Instant::now();
+    // `None` until the first probe, which runs on the first tick: startup has
+    // already used up much of the watchdog's time (`docs/BUGS.md` B279).
+    let mut last_ping: Option<Instant> = None;
+    let mut restored = false;
     // Per-lane completion counts from the previous tick, to tell a queue that is
     // being worked through from one that is not moving at all.
     let mut last_completed = (0_u64, 0_u64);
@@ -79,16 +87,22 @@ pub(crate) fn run(core: Core, control_socket: PathBuf) {
         // throw away in-flight uploads. The probe decides that; a stall only
         // gets said out loud.
         if let Some(period) = watchdog
-            && last_ping.elapsed() >= period
+            && ping_due(last_ping, period)
         {
             if probe(&control_socket) {
+                if !restored {
+                    // Startup ran on the longer timeout the daemon asked for.
+                    // The socket answers now, so the unit's own one applies.
+                    systemd::restore_watchdog();
+                    restored = true;
+                }
                 systemd::watchdog_ping();
             } else {
                 warn!(
                     "daemon did not answer its own control socket; withholding the watchdog ping"
                 );
             }
-            last_ping = Instant::now();
+            last_ping = Some(Instant::now());
         }
     }
 }
@@ -137,9 +151,34 @@ fn report_stalls(report: &pdfs_core::control::Diagnostics, last_completed: (u64,
             "the transfer lane has not completed a job since the last check"
         );
     }
+    // The engine is one thread for every synced folder, so a dead or stuck one
+    // stops all of them while the worker pool looks idle (B259).
+    if let Some(sync) = &report.sync {
+        if !sync.running {
+            stalled = true;
+            warn!(
+                "the sync engine is not running; synced folders do not sync until the daemon restarts"
+            );
+        } else if let Some(folder) = sync.pass_folder
+            && sync.pass_idle_secs >= SYNC_STALL_AFTER.as_secs()
+        {
+            stalled = true;
+            warn!(
+                folder,
+                age_secs = sync.pass_age_secs,
+                idle_secs = sync.pass_idle_secs,
+                "a sync pass has not reported progress for a long time"
+            );
+        }
+    }
     stalled
 }
 
+/// Whether the watchdog wants its next ping. The first one is due at once.
+fn ping_due(last_ping: Option<Instant>, period: Duration) -> bool {
+    last_ping.is_none_or(|at| at.elapsed() >= period)
+}
+
 /// One round trip over the control socket: connect, ask for the cheapest
 /// request there is, read the answer.
 ///
@@ -169,7 +208,7 @@ fn probe(control_socket: &Path) -> bool {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use pdfs_core::control::{Diagnostics, InflightRequest, WorkerState};
+    use pdfs_core::control::{Diagnostics, InflightRequest, SyncEngineState, WorkerState};
 
     fn busy_worker(age_secs: u64) -> WorkerState {
         WorkerState {
@@ -180,6 +219,18 @@ mod tests {
         }
     }
 
+    /// The first ping goes out on the first tick, not a full period after the
+    /// supervisor starts: startup has already spent most of the watchdog's time
+    /// (`docs/BUGS.md` B279).
+    #[test]
+    fn first_watchdog_ping_is_due_at_once() {
+        let period = Duration::from_secs(60);
+        assert!(ping_due(None, period));
+        assert!(!ping_due(Some(Instant::now()), period));
+        let long_ago = Instant::now().checked_sub(period).expect("uptime");
+        assert!(ping_due(Some(long_ago), period));
+    }
+
     /// A worker doing normal work must not be reported: a WARN every tick is a
     /// WARN nobody reads.
     #[test]
@@ -226,4 +277,45 @@ mod tests {
         assert!(!report_stalls(&report, (0, 30)));
         assert!(report_stalls(&report, (0, 40)));
     }
+
+    fn with_sync(sync: SyncEngineState) -> Diagnostics {
+        Diagnostics {
+            sync: Some(sync),
+            ..Default::default()
+        }
+    }
+
+    /// A sync engine that has ended stops every synced folder while the
+    /// workers look idle, which is what issue #53 looked like (B259).
+    #[test]
+    fn a_stopped_sync_engine_is_a_stall() {
+        assert!(report_stalls(
+            &with_sync(SyncEngineState::default()),
+            (0, 0)
+        ));
+    }
+
+    /// A pass that keeps reporting progress is working, however long it runs;
+    /// one that has gone quiet past the threshold is not.
+    #[test]
+    fn only_a_quiet_sync_pass_is_a_stall() {
+        let busy = SyncEngineState {
+            running: true,
+            pass_folder: Some(3),
+            pass_age_secs: SYNC_STALL_AFTER.as_secs() * 4,
+            pass_idle_secs: 5,
+            panics: 0,
+        };
+        assert!(!report_stalls(&with_sync(busy.clone()), (0, 0)));
+        let quiet = SyncEngineState {
+            pass_idle_secs: SYNC_STALL_AFTER.as_secs(),
+            ..busy
+        };
+        assert!(report_stalls(&with_sync(quiet), (0, 0)));
+        let idle = SyncEngineState {
+            running: true,
+            ..Default::default()
+        };
+        assert!(!report_stalls(&with_sync(idle), (0, 0)));
+    }
 }

crates/pdfs-fuse/src/sweep.rs

@@ -37,10 +37,12 @@ const CONFLICT_SWEEP_INTERVAL: Duration = Duration::from_secs(300);
 /// fresh mount does at startup (hydrate, recover, initial enumeration).
 const CONFLICT_SWEEP_WARMUP: Duration = Duration::from_secs(30);
 
-/// Strip a ` (sync-conflict <stamp>)` (optionally `-<n>`) marker from `name`,
-/// returning the original file name it was a copy of. `None` when `name` is not a
-/// conflict copy. Inverse of the `conflict_name` / `conflict_path_with_suffix`
-/// formats, so the two halves of the product agree on what a conflict is.
+/// Strip a ` (sync-conflict <label> <stamp>)` (optionally `-<n>`) marker from
+/// `name`, returning the original file name it was a copy of. The label names
+/// the computer that made the copy (B251); copies made before it have the bare
+/// stamp. `None` when `name` is not a conflict copy. Inverse of the
+/// `conflict_name` / `conflict_path_with_suffix` formats, so the two halves of
+/// the product agree on what a conflict is.
 pub(crate) fn conflict_base_name(name: &str) -> Option<String> {
     const MARKER: &str = " (sync-conflict ";
     let start = name.find(MARKER)?;
@@ -48,6 +50,20 @@ pub(crate) fn conflict_base_name(name: &str) -> Option<String> {
     let close_rel = name[after..].find(')')?;
     let close = after + close_rel;
     let inner = &name[after..close];
+    // A label is one token of the characters `conflict_label_of` keeps.
+    let inner = match inner.rsplit_once(' ') {
+        Some((label, token)) => {
+            let label_ok = !label.is_empty()
+                && label
+                    .chars()
+                    .all(|c| c.is_ascii_alphanumeric() || matches!(c, '-' | '_' | '.'));
+            if !label_ok {
+                return None;
+            }
+            token
+        }
+        None => inner,
+    };
     // The token is `<digits>` or `<digits>-<digits>`; reject anything else so a
     // file that merely happens to contain the phrase is not mistaken for a copy.
     let mut parts = inner.splitn(2, '-');
@@ -486,6 +502,24 @@ mod tests {
             conflict_base_name("notes (sync-conflict 1700-3).txt").as_deref(),
             Some("notes.txt")
         );
+        // Named after the computer that made it (B251).
+        assert_eq!(
+            conflict_base_name("notes (sync-conflict laptop 1700).txt").as_deref(),
+            Some("notes.txt")
+        );
+        assert_eq!(
+            conflict_base_name("notes (sync-conflict my-pc.local 1700-2).txt").as_deref(),
+            Some("notes.txt")
+        );
+        assert_eq!(
+            conflict_base_name(&crate::conflict_name("notes.txt", 1700)).as_deref(),
+            Some("notes.txt")
+        );
+        assert_eq!(
+            conflict_base_name("x (sync-conflict two words 1).txt"),
+            None
+        );
+        assert_eq!(conflict_base_name("x (sync-conflict  1).txt"), None);
         // Not a conflict copy.
         assert_eq!(conflict_base_name("report.xml"), None);
         // Looks close but the token is not a stamp.

crates/pdfs-fuse/src/sync/engine.rs

@@ -1,5 +1,11 @@
 //! Filesystem watcher, polling, and debounce control plane.
 
+use std::panic::AssertUnwindSafe;
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+
+use pdfs_core::control::SyncEngineState;
+use tracing::error;
+
 use super::*;
 
 /// How long the watcher must go quiet before a burst counts as finished.
@@ -22,7 +28,10 @@ const POLL_INTERVAL: Duration = Duration::from_secs(120);
 /// per-item work is a network round-trip, so a folder with thousands of files is
 /// unusable done one-at-a-time; this bounds concurrency like the bulk-upload
 /// engine does.
-pub(super) const SYNC_CONCURRENCY: usize = 8;
+pub(crate) const SYNC_CONCURRENCY: usize = 8;
+/// How long after a failed watch the engine tries the watches again. Each try
+/// walks the folder's whole tree, so not on every burst.
+const REWATCH_RETRY: Duration = Duration::from_secs(600);
 
 /// A message to the sync engine's control thread.
 pub(crate) enum SyncMsg {
@@ -53,32 +62,159 @@ pub(crate) fn spawn(core: Core, rx: Receiver<SyncMsg>) -> Option<std::thread::Jo
     }
 }
 
+/// Whether the engine is alive and which pass it is on, for
+/// [`Core::diagnostics`] and the supervisor.
+///
+/// A panic in a pass used to end the engine thread. Every later add, sync-now,
+/// file event and poll then went into a channel nobody read, the folder stayed
+/// `syncing`, and nothing said so until a restart (`docs/BUGS.md` B259).
+#[derive(Default)]
+pub(crate) struct EngineHealth {
+    running: AtomicBool,
+    pass: Mutex<Option<PassClock>>,
+    panics: AtomicU64,
+}
+
+#[derive(Clone, Copy)]
+struct PassClock {
+    folder: i64,
+    started: Instant,
+    moved: Instant,
+}
+
+impl EngineHealth {
+    /// Note that the running pass reported progress.
+    pub(crate) fn moved(&self) {
+        if let Some(pass) = self.pass.lock().as_mut() {
+            pass.moved = Instant::now();
+        }
+    }
+
+    /// The engine's state now. `try_lock`, like the rest of the diagnostics:
+    /// a report must not wait on the thing it reports about.
+    pub(crate) fn report(&self) -> SyncEngineState {
+        let pass = self.pass.try_lock().and_then(|pass| *pass);
+        SyncEngineState {
+            running: self.running.load(Ordering::Relaxed),
+            pass_folder: pass.map(|p| p.folder),
+            pass_age_secs: pass.map_or(0, |p| p.started.elapsed().as_secs()),
+            pass_idle_secs: pass.map_or(0, |p| p.moved.elapsed().as_secs()),
+            panics: self.panics.load(Ordering::Relaxed),
+        }
+    }
+
+    /// Run `pass` over `folder` as the current pass. Returns `false` when it
+    /// panicked: the panic ends that pass, not the engine.
+    pub(super) fn contain(&self, folder: i64, pass: impl FnOnce()) -> bool {
+        let now = Instant::now();
+        *self.pass.lock() = Some(PassClock {
+            folder,
+            started: now,
+            moved: now,
+        });
+        let finished = std::panic::catch_unwind(AssertUnwindSafe(pass)).is_ok();
+        *self.pass.lock() = None;
+        if !finished {
+            self.panics.fetch_add(1, Ordering::Relaxed);
+        }
+        finished
+    }
+}
+
+/// Marks the engine running for as long as it lives.
+pub(super) struct Running<'a>(&'a EngineHealth);
+
+impl<'a> Running<'a> {
+    pub(super) fn start(health: &'a EngineHealth) -> Self {
+        health.running.store(true, Ordering::Relaxed);
+        Self(health)
+    }
+}
+
+impl Drop for Running<'_> {
+    fn drop(&mut self) {
+        self.0.running.store(false, Ordering::Relaxed);
+        if std::thread::panicking() {
+            error!("sync engine stopped by a panic; nothing syncs until the daemon restarts");
+        }
+    }
+}
+
+/// One folder's pass, contained: a panic in it sets the folder to `error` and
+/// leaves the engine running for the next one.
+fn run_pass(core: &Core, folder: &StoredSyncFolder) {
+    if core
+        .sync_engine
+        .contain(folder.id, || core.reconcile_folder(folder))
+    {
+        return;
+    }
+    core.progress_end(folder.id);
+    let _ = core
+        .db
+        .sync_folder_set_state(folder.id, "error", folder.last_sync);
+    error!(
+        id = folder.id,
+        path = %folder.local_path,
+        "sync: pass panicked; the folder is set to error and tried again on the next poll"
+    );
+    core.log_activity(
+        ActivityKind::Sync,
+        format!("sync failed for {}", base_name(&folder.local_path)),
+        "an internal error stopped the pass; it is tried again on the next poll",
+        false,
+    );
+}
+
+/// The pass a `Reconcile(id)` asked for. A folder removed since, or one the
+/// database cannot read, is said so rather than dropped in silence.
+fn run_pass_by_id(core: &Core, id: i64) {
+    match core.db.sync_folder_get(id) {
+        Ok(Some(folder)) => run_pass(core, &folder),
+        Ok(None) => debug!(id, "sync: folder removed before its pass; skipping"),
+        Err(e) => warn!(id, error = ?e, "sync: cannot read folder; skipping its pass"),
+    }
+}
+
 /// The engine control loop. Single-threaded so reconcile passes never overlap.
 fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
+    let health = core.sync_engine.clone();
+    let _running = Running::start(&health);
     // Paths the watcher currently covers, mapped to their folder id, so an event
     // path can be resolved back to the folder it belongs to.
     let watched: Arc<Mutex<Vec<(PathBuf, i64)>>> = Arc::new(Mutex::new(Vec::new()));
 
     let tx_events = core.sync_tx.clone();
     let watched_events = watched.clone();
-    let mut watcher =
-        match notify::recommended_watcher(move |res: notify::Result<notify::Event>| {
-            let Ok(event) = res else { return };
-            // Ignore pure metadata/access noise; content changes are what matter.
-            if matches!(event.kind, notify::EventKind::Access(_)) {
-                return;
-            }
-            let msg = event_target(&watched_events.lock(), &event.paths);
-            let _ = tx_events.send(msg);
-        }) {
-            Ok(w) => w,
+    let handler = move |res: notify::Result<notify::Event>| {
+        let event = match res {
+            Ok(event) => event,
+            // Running out of inotify watches for a new subfolder, say: that
+            // subfolder's changes are then found by the poll only (B262).
             Err(e) => {
-                warn!(error = %e, "filesystem watcher unavailable; sync is poll-only");
-                // Still run the loop so polling and explicit SyncNow work.
-                poll_only_loop(&core, rx);
+                warn!(error = %e, "sync: filesystem watcher error");
                 return;
             }
         };
+        // Ignore pure metadata/access noise; content changes are what matter.
+        if matches!(event.kind, notify::EventKind::Access(_)) {
+            return;
+        }
+        let msg = event_target(&watched_events.lock(), &event.paths);
+        let _ = tx_events.send(msg);
+    };
+    // The local walk skips symlinks, so following them here would only watch
+    // trees outside the folder, and run passes over it for changes made there.
+    let config = notify::Config::default().with_follow_symlinks(false);
+    let mut watcher = match notify::RecommendedWatcher::new(handler, config) {
+        Ok(w) => w,
+        Err(e) => {
+            warn!(error = %e, "filesystem watcher unavailable; sync is poll-only");
+            // Still run the loop so polling and explicit SyncNow work.
+            poll_only_loop(&core, rx);
+            return;
+        }
+    };
 
     // Periodic remote poll.
     {
@@ -96,8 +232,9 @@ fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
             .ok();
     }
 
-    rewatch(&core, &mut watcher, &watched);
-    reconcile_all(&core);
+    let mut unwatched = rewatch(&core, &mut watcher, &watched);
+    let mut last_rewatch = Instant::now();
+    run_burst(&core, &HashSet::new(), true);
 
     while let Ok(msg) = rx.recv() {
         let mut ids: HashSet<i64> = HashSet::new();
@@ -110,21 +247,16 @@ fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
             return;
         }
 
+        // A folder whose watch failed is tried again now and then, not only
+        // when the folder set changes.
+        if unwatched && last_rewatch.elapsed() >= REWATCH_RETRY {
+            do_rewatch = true;
+        }
         if do_rewatch {
-            rewatch(&core, &mut watcher, &watched);
-        }
-        if all {
-            reconcile_all(&core);
-        } else {
-            for id in ids {
-                if core.sync_paused() {
-                    break;
-                }
-                if let Ok(Some(folder)) = core.db.sync_folder_get(id) {
-                    core.reconcile_folder(&folder);
-                }
-            }
+            unwatched = rewatch(&core, &mut watcher, &watched);
+            last_rewatch = Instant::now();
         }
+        run_burst(&core, &ids, all);
     }
 }
 
@@ -141,7 +273,7 @@ fn poll_only_loop(core: &Core, rx: Receiver<SyncMsg>) {
             }
         });
     }
-    reconcile_all(core);
+    run_burst(core, &HashSet::new(), true);
     while let Ok(msg) = rx.recv() {
         let mut ids: HashSet<i64> = HashSet::new();
         let mut all = false;
@@ -152,21 +284,59 @@ fn poll_only_loop(core: &Core, rx: Receiver<SyncMsg>) {
             info!("sync engine stopping");
             return;
         }
-        if all {
-            reconcile_all(core);
-        } else {
-            for id in ids {
-                if core.sync_paused() {
-                    break;
-                }
-                if let Ok(Some(folder)) = core.db.sync_folder_get(id) {
-                    core.reconcile_folder(&folder);
-                }
+        run_burst(core, &ids, all);
+    }
+}
+
+/// Run the passes one burst asked for: the folders named by id, then, when the
+/// burst also holds a `ReconcileAll`, every other folder.
+///
+/// The named folders go first. A poll's `ReconcileAll` in the same burst used
+/// to take their place, and a folder just added, which has the highest id,
+/// waited behind a full pass over every other folder (`docs/BUGS.md` B260).
+///
+/// Skipped while sync is paused, and cut short when a pause lands between
+/// passes: the resume sends a fresh [`SyncMsg::ReconcileAll`], which walks
+/// everything the watcher reported meanwhile.
+fn run_burst(core: &Core, ids: &HashSet<i64>, all: bool) {
+    if core.sync_paused() {
+        debug!("sync: paused, skipping reconcile");
+        return;
+    }
+    let folders = if all {
+        match core.db.sync_folder_list() {
+            Ok(folders) => folders,
+            Err(e) => {
+                warn!(error = ?e, "sync: cannot list folders");
+                Vec::new()
             }
         }
+    } else {
+        Vec::new()
+    };
+    let listed: Vec<i64> = folders.iter().map(|f| f.id).collect();
+    for id in burst_order(ids, &listed) {
+        if core.sync_paused() {
+            break;
+        }
+        // A folder named by id is read again: it may have been added or
+        // changed after the list was read.
+        match folders.iter().find(|f| f.id == id) {
+            Some(folder) if !ids.contains(&id) => run_pass(core, folder),
+            _ => run_pass_by_id(core, id),
+        }
     }
 }
 
+/// The order of a burst's passes: the folders named by id, lowest first, then
+/// the rest of `listed` in its own order.
+pub(super) fn burst_order(ids: &HashSet<i64>, listed: &[i64]) -> Vec<i64> {
+    let mut order: Vec<i64> = ids.iter().copied().collect();
+    order.sort_unstable();
+    order.extend(listed.iter().copied().filter(|id| !ids.contains(id)));
+    order
+}
+
 /// Absorb the rest of an event burst, returning once the watcher has been quiet
 /// for `quiet` or `cap` has elapsed since the first event — whichever comes
 /// first. The caller has already classified the event that opened the burst.
@@ -238,26 +408,6 @@ pub(super) fn classify(
     true
 }
 
-/// Reconcile every mirror folder in turn. Skipped while sync is paused: the
-/// resume sends a fresh [`SyncMsg::ReconcileAll`], which walks everything the
-/// watcher reported meanwhile.
-fn reconcile_all(core: &Core) {
-    if core.sync_paused() {
-        debug!("sync: paused, skipping reconcile");
-        return;
-    }
-    let folders = match core.db.sync_folder_list() {
-        Ok(f) => f,
-        Err(e) => {
-            warn!(error = ?e, "sync: cannot list folders");
-            return;
-        }
-    };
-    for folder in folders {
-        core.reconcile_folder(&folder);
-    }
-}
-
 /// The reconcile a watcher event asks for: the one mirror folder all its paths
 /// lie in, so an edit in one folder does not walk every other one too. An event
 /// that spans folders, or that no watched folder claims (a watch list a moment
@@ -278,7 +428,8 @@ pub(super) fn event_target(watched: &[(PathBuf, i64)], paths: &[PathBuf]) -> Syn
 }
 
 /// Bring the filesystem watches in line with the current mirror-folder set:
-/// watch newly-added folders, drop removed ones.
+/// watch newly-added folders, drop removed ones. Returns whether a folder is
+/// left unwatched because its watch failed.
 ///
 /// The watch calls run on a copy, outside the lock: the watcher's event
 /// callback takes the same lock, and a backend that hands a watch request to
@@ -287,7 +438,7 @@ fn rewatch(
     core: &Core,
     watcher: &mut notify::RecommendedWatcher,
     watched: &Mutex<Vec<(PathBuf, i64)>>,
-) {
+) -> bool {
     let want: Vec<(PathBuf, i64)> = match core.db.sync_folder_list() {
         Ok(f) => f
             .into_iter()
@@ -296,30 +447,60 @@ fn rewatch(
             .collect(),
         Err(e) => {
             warn!(error = ?e, "sync: cannot list folders to watch");
-            return;
+            return false;
         }
     };
     let mut have = watched.lock().clone();
     // Drop watches no longer wanted.
-    have.retain(|(path, _)| {
-        if want.iter().any(|(p, _)| p == path) {
-            true
-        } else {
-            let _ = watcher.unwatch(path);
-            false
-        }
-    });
+    for path in keep_wanted(&mut have, &want) {
+        let _ = watcher.unwatch(&path);
+    }
     // Add newly wanted watches.
+    let mut failed = false;
     for (path, id) in &want {
         if have.iter().any(|(p, _)| p == path) {
             continue;
         }
         match watcher.watch(path, RecursiveMode::Recursive) {
             Ok(()) => have.push((path.clone(), *id)),
-            Err(e) => warn!(path = %path.display(), error = %e, "sync: watch failed"),
+            Err(e) => {
+                // A recursive watch that fails partway keeps the watches it had
+                // added. Their events would match no folder and run a pass over
+                // every one, and they hold watches the next folder needs (B262).
+                let _ = watcher.unwatch(path);
+                failed = true;
+                warn!(
+                    path = %path.display(),
+                    error = %e,
+                    "sync: watch failed; the poll finds this folder's changes until a retry \
+                     works. A low fs.inotify.max_user_watches is the usual cause"
+                );
+            }
         }
     }
     *watched.lock() = have;
+    failed
+}
+
+/// Keep the watches in `have` that `want` still asks for, and return the paths
+/// of the others, to unwatch.
+///
+/// A path is matched alone, but takes the id `want` gives it: a folder removed
+/// and added again in one burst keeps its watch, and its events go to the new
+/// row rather than to the removed one (`docs/BUGS.md` B272).
+pub(super) fn keep_wanted(have: &mut Vec<(PathBuf, i64)>, want: &[(PathBuf, i64)]) -> Vec<PathBuf> {
+    let mut dropped = Vec::new();
+    have.retain_mut(|(path, id)| match want.iter().find(|(p, _)| p == path) {
+        Some((_, wanted)) => {
+            *id = *wanted;
+            true
+        }
+        None => {
+            dropped.push(path.clone());
+            false
+        }
+    });
+    dropped
 }
 
 // ---- reconcile ------------------------------------------------------------

crates/pdfs-fuse/src/sync/model.rs

@@ -83,6 +83,46 @@ pub(super) struct RemoteItem {
     pub(super) is_dir: bool,
     pub(super) mtime: i64,
     pub(super) size: i64,
+    /// The active revision's id. The light walk carries it for every file, so
+    /// it is the signal that tells another client's new revision from a link
+    /// merely re-stamped.
+    pub(super) revision: Option<String>,
+    /// The active revision's content SHA-1, read only for files the walk
+    /// enumerated in full (no baseline, or a moved mtime). `None` is never
+    /// proof of anything.
+    pub(super) sha1: Option<String>,
+}
+
+/// What a pass saw of a remote file: the signature its baseline records once
+/// the file is synced, and what an upload checks Drive still holds before it
+/// supersedes it.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub(super) struct RemoteSeen {
+    pub(super) mtime: i64,
+    pub(super) size: i64,
+    pub(super) revision: Option<String>,
+}
+
+impl RemoteSeen {
+    /// Whether `node` is still the revision this was taken from. The revision
+    /// id decides it when both sides have one; otherwise the modification time
+    /// and size, which is all a baseline row from before schema 44 holds.
+    pub(super) fn still_current(&self, node: &Node) -> bool {
+        match (&self.revision, crate::node_revision_id(node)) {
+            (Some(seen), Some(now)) => *seen == now,
+            _ => (self.mtime, self.size) == remote_file_sig(node),
+        }
+    }
+}
+
+impl From<&RemoteItem> for RemoteSeen {
+    fn from(item: &RemoteItem) -> Self {
+        Self {
+            mtime: item.mtime,
+            size: item.size,
+            revision: item.revision.clone(),
+        }
+    }
 }
 
 /// The result of a reconcile pass: what it moved, how many paths were kept as
@@ -113,7 +153,7 @@ impl Outcome {
             Applied::Uploaded => self.uploaded += 1,
             Applied::Downloaded => self.downloaded += 1,
             Applied::Conflict => self.conflicts += 1,
-            Applied::Vanished => {}
+            Applied::Vanished | Applied::Adopted => {}
         }
     }
 
@@ -157,10 +197,16 @@ pub(super) enum Pending {
     CreateDir { rel: String, parent: NodeUid },
     /// Upload a brand-new local file into `parent`.
     UploadNew { rel: String, parent: NodeUid },
-    /// Upload a changed local file as a new revision of `uid`.
-    UploadRevision { rel: String, uid: NodeUid },
-    /// Download remote `uid` to the local path, stamping `mtime`. `size` is the
-    /// remote's reported size, used as the transfer's expected total.
+    /// Upload a changed local file as a new revision of `uid`, if Drive still
+    /// holds the revision `seen` describes (B249).
+    UploadRevision {
+        rel: String,
+        uid: NodeUid,
+        seen: RemoteSeen,
+    },
+    /// Download remote `uid` to the local path, stamping `seen.mtime`.
+    /// `seen.size` is the remote's reported size, used as the transfer's
+    /// expected total.
     ///
     /// `local` is what the planning walk saw at this path, or `None` if nothing
     /// was there. A download can run for minutes, so the apply step revalidates
@@ -170,16 +216,26 @@ pub(super) enum Pending {
     Download {
         rel: String,
         uid: NodeUid,
-        mtime: i64,
-        size: i64,
+        seen: RemoteSeen,
         local: Option<LocalSig>,
     },
+    /// First sync of a path present on both sides at the same size, with a
+    /// digest on Drive: hash the local file, and record the baseline if it holds
+    /// the same bytes. A different file of the same size goes the way of
+    /// [`Pending::Conflict`]: two machines syncing one folder must not read as
+    /// in step while they hold different content.
+    Adopt {
+        rel: String,
+        uid: NodeUid,
+        seen: RemoteSeen,
+        sha1: String,
+        local: LocalSig,
+    },
     /// Both sides changed: set the local copy aside, then download remote `uid`.
     Conflict {
         rel: String,
         uid: NodeUid,
-        mtime: i64,
-        size: i64,
+        seen: RemoteSeen,
     },
     /// Both sides changed during a [`push pass`](Core::push_pass): upload the local
     /// copy into `parent` under a conflict name, leaving the remote file as it is.
@@ -194,6 +250,7 @@ impl Pending {
             | Pending::UploadNew { rel, .. }
             | Pending::UploadRevision { rel, .. }
             | Pending::Download { rel, .. }
+            | Pending::Adopt { rel, .. }
             | Pending::Conflict { rel, .. }
             | Pending::PushConflict { rel, .. } => rel,
         }
@@ -206,7 +263,9 @@ impl Pending {
             Pending::UploadNew { .. }
             | Pending::UploadRevision { .. }
             | Pending::PushConflict { .. } => ActivityKind::Upload,
-            Pending::Download { .. } | Pending::Conflict { .. } => ActivityKind::Download,
+            Pending::Download { .. } | Pending::Adopt { .. } | Pending::Conflict { .. } => {
+                ActivityKind::Download
+            }
         }
     }
 
@@ -217,6 +276,7 @@ impl Pending {
             Pending::UploadNew { .. } => "new file",
             Pending::UploadRevision { .. } => "new version",
             Pending::Download { .. } => "from Drive",
+            Pending::Adopt { .. } => "already the same on Drive",
             Pending::Conflict { .. } => "local changes kept as a conflict copy",
             Pending::PushConflict { .. } => "local changes uploaded as a conflict copy",
         }

crates/pdfs-fuse/src/sync/planner.rs

@@ -180,33 +180,220 @@ pub(super) fn local_deletions<B, L>(
     missing
 }
 
-/// Refuse to run a pass whose local side has vanished in its entirety.
+/// How many tracked paths a folder needs before a mass disappearance, short of
+/// a total one, trips a wipe guard. Below this, a few survivors say little.
+const MASS_LOSS_MIN_PATHS: usize = 20;
+
+/// The share of a large folder's tracked paths that may vanish in one pass, in
+/// tenths, before a wipe guard stops it: 9 of 10 and up is refused.
+const MASS_LOSS_TENTHS: usize = 9;
+
+/// Whether `missing` of `total` tracked paths gone at once looks like a lost
+/// tree rather than deletions. All of them always does. Most of a large
+/// folder does too: one surviving file used to clear the guard, so a
+/// half-mounted disk, or a script that emptied the folder and wrote one file
+/// back, trashed everything else on Drive (B270).
+fn looks_like_a_wipe(missing: usize, total: usize) -> bool {
+    total > 0
+        && (missing == total
+            || (total >= MASS_LOSS_MIN_PATHS && missing * 10 >= total * MASS_LOSS_TENTHS))
+}
+
+/// Refuse to run a pass whose local side has vanished in its entirety, or
+/// nearly so ([`looks_like_a_wipe`]).
 ///
-/// When every baseline path is absent locally, the likely cause is an unavailable
-/// mount or unreadable folder rather than a deliberate whole-tree deletion.
-/// One surviving path is enough to clear the guard.
+/// When the synced paths are all or nearly all absent locally, the likely
+/// cause is an unavailable mount or unreadable folder rather than a deliberate
+/// deletion of the whole tree.
 pub(super) fn guard_local_wipe<B, L>(
     baseline: &HashMap<String, B>,
     local: &HashMap<String, L>,
 ) -> Result<(), String> {
-    if !baseline.is_empty() && baseline.keys().all(|rel| !local.contains_key(rel)) {
+    let missing = baseline
+        .keys()
+        .filter(|rel| !local.contains_key(*rel))
+        .count();
+    if looks_like_a_wipe(missing, baseline.len()) {
         return Err(format!(
-            "every one of the {} synced paths is missing locally; refusing to trash \
-             them on Drive. Check that the folder is mounted and readable.",
+            "{missing} of the {} synced paths are missing locally; refusing to trash \
+             them on Drive. Check that the folder is mounted and readable; to download \
+             them again, sync the folder from scratch.",
             baseline.len()
         ));
     }
     Ok(())
 }
 
+/// Refuse to run a pass whose remote side has vanished in its entirety, or
+/// nearly so: the remote twin of [`guard_local_wipe`].
+///
+/// An empty or truncated remote walk reads to the planner as "Drive deleted
+/// everything", which a pass answers by deleting the local copies. When all or
+/// nearly all synced paths are gone from Drive at once, a failed listing is far
+/// likelier than a deliberate wipe of the folder, so the pass stops instead.
+pub(super) fn guard_remote_wipe<B, R>(
+    baseline: &HashMap<String, B>,
+    remote: &HashMap<String, R>,
+) -> Result<(), String> {
+    let missing = baseline
+        .keys()
+        .filter(|rel| !remote.contains_key(*rel))
+        .count();
+    if looks_like_a_wipe(missing, baseline.len()) {
+        return Err(format!(
+            "{missing} of the {} synced paths are missing on Proton Drive; refusing to \
+             delete them here. If they were deleted on purpose, remove the folder from sync; \
+             to upload them again, sync the folder from scratch.",
+            baseline.len()
+        ));
+    }
+    Ok(())
+}
+
+/// What a remote walk saw but could not read: a node the SDK left out because
+/// it would not decrypt, or a file whose size could not be read.
+///
+/// A path missing from the walk is read as deleted on Drive, so a pass must
+/// not classify one it only failed to read. Since a node that failed to decrypt
+/// has no name, all a walk can say is that a folder's listing came back short;
+/// every path under that folder that the walk did not return is then left out,
+/// as [`Unscanned`] leaves out what the local scan could not read.
+#[derive(Default)]
+pub(super) struct RemoteGaps {
+    /// Folders whose listing came back with fewer nodes than it named.
+    short: HashSet<String>,
+    /// Paths seen, but whose entry could not be read.
+    unread: HashSet<String>,
+    /// Folders whose listing failed outright, after the SDK's retries. Nothing
+    /// under one is known, so all of it is left out of the pass (B271).
+    unlisted: HashSet<String>,
+}
+
+impl RemoteGaps {
+    /// The listing of `folder` named nodes that did not come back.
+    pub(super) fn short_listing(&mut self, folder: &str) {
+        self.short.insert(folder.to_string());
+    }
+
+    /// `rel` is on Drive, but the walk could not read what it needs of it.
+    pub(super) fn unread(&mut self, rel: String) {
+        self.unread.insert(rel);
+    }
+
+    /// The listing of `folder` failed, so nothing under it was walked.
+    pub(super) fn unlisted(&mut self, folder: &str) {
+        self.unlisted.insert(folder.to_string());
+    }
+
+    pub(super) fn is_empty(&self) -> bool {
+        self.short.is_empty() && self.unread.is_empty() && self.unlisted.is_empty()
+    }
+
+    /// Whether `rel` may be missing from `remote` only because the walk could
+    /// not read it. A path the walk returned is never hidden.
+    pub(super) fn hides<R>(
+        &self,
+        rel: &str,
+        remote: &HashMap<String, R>,
+        remote_dirs: &HashMap<String, NodeUid>,
+    ) -> bool {
+        if self.is_empty() || remote.contains_key(rel) {
+            return false;
+        }
+        if self.unread.contains(rel) {
+            return true;
+        }
+        // The deepest folder the walk did list decides: under a short listing,
+        // anything not returned may be one of the nodes it could not read.
+        let mut at = parent_rel(rel);
+        loop {
+            if remote_dirs.contains_key(at) {
+                return self.short.contains(at) || self.unlisted.contains(at);
+            }
+            if at.is_empty() {
+                return false;
+            }
+            at = parent_rel(at);
+        }
+    }
+
+    /// The folders to name to the user, sorted.
+    pub(super) fn report(&self) -> Vec<String> {
+        let mut lines: Vec<String> = self
+            .short
+            .iter()
+            .map(|rel| {
+                let shown = if rel.is_empty() { "the folder" } else { rel };
+                format!("{shown} (items on Proton Drive that cannot be read)")
+            })
+            .chain(
+                self.unread
+                    .iter()
+                    .map(|rel| format!("{rel} (cannot be read on Proton Drive)")),
+            )
+            .chain(self.unlisted.iter().map(|rel| {
+                format!("{rel} (could not be listed on Proton Drive; tried again next pass)")
+            }))
+            .collect();
+        lines.sort_unstable();
+        lines
+    }
+}
+
+/// Why the remote folder at `rel` must not be trashed although it was deleted
+/// here: something under it is new or changed on Drive since the last sync,
+/// so it is another device's work that this computer has never had.
+///
+/// Trashing the folder would take that work with it, and the next pass would
+/// then delete the copy this pass just downloaded. `None` when everything under
+/// it is exactly what the baseline recorded.
+pub(super) fn remote_subtree_changed(
+    rel: &str,
+    remote: &HashMap<String, RemoteItem>,
+    baseline: &HashMap<String, StoredSyncEntry>,
+) -> Option<String> {
+    let prefix = format!("{rel}/");
+    let mut changed: Vec<&String> = remote
+        .iter()
+        .filter(|(path, _)| path.starts_with(&prefix))
+        .filter(|(path, item)| match baseline.get(*path) {
+            None => true,
+            Some(_) if item.is_dir => false,
+            Some(base) => {
+                remote_sig(base) != Some((item.mtime, item.size))
+                    || revision_moved(Some(base), item.revision.as_deref())
+            }
+        })
+        .map(|(path, _)| path)
+        .collect();
+    changed.sort_unstable();
+    changed
+        .first()
+        .map(|path| format!("{path} is new or changed on Proton Drive"))
+}
+
 /// The size the baseline recorded for `rel`, if its remote signature's mtime
-/// still matches `mtime`.
+/// still matches `mtime` and its revision is still `revision`.
+///
+/// A row without a revision id, while Drive reports one, cannot vouch for the
+/// revision, so the size is read for real. Such a row comes from before
+/// schema 44, or from an upload Drive did not list yet when it was read back.
+/// Another computer's revision in the same second as that upload kept the
+/// modification time, and only the size could show it (B254). The pass then
+/// records the id on the row, so this costs one read per row.
 pub(super) fn unchanged_remote_size(
     baseline: &HashMap<String, StoredSyncEntry>,
     rel: &str,
     mtime: i64,
+    revision: Option<&str>,
 ) -> Option<i64> {
-    match baseline.get(rel).and_then(remote_sig) {
+    let base = baseline.get(rel)?;
+    if revision_moved(Some(base), revision)
+        || (base.remote_revision_id.is_none() && revision.is_some())
+    {
+        return None;
+    }
+    match remote_sig(base) {
         Some((recorded, size)) if recorded == mtime => Some(size),
         _ => None,
     }
@@ -221,6 +408,17 @@ pub(super) fn join_rel(prefix: &str, name: &str) -> String {
     }
 }
 
+/// Whether Drive's active revision `now` is not the one the baseline row was
+/// synced at. Only a revision id on both sides can say so; a row from before
+/// schema 44, or a node read without one, leaves it to the modification time
+/// and size.
+pub(super) fn revision_moved(base: Option<&StoredSyncEntry>, now: Option<&str>) -> bool {
+    match (base.and_then(|b| b.remote_revision_id.as_deref()), now) {
+        (Some(recorded), Some(now)) => recorded != now,
+        _ => false,
+    }
+}
+
 /// The stored remote signature of a baseline row, if it has one.
 pub(super) fn remote_sig(e: &StoredSyncEntry) -> Option<(i64, i64)> {
     match (&e.remote_rev, &e.remote_hash) {
@@ -251,7 +449,8 @@ pub(super) fn rel_to_path(rel: &str) -> PathBuf {
     rel.split('/').collect()
 }
 
-/// The name for a conflict copy of `path`, e.g. `notes (sync-conflict 1700000000).txt`.
+/// The name for a conflict copy of `path`, e.g.
+/// `notes (sync-conflict laptop 1700000000).txt`.
 #[cfg(test)]
 pub(super) fn conflict_path(path: &Path, stamp: i64) -> PathBuf {
     conflict_path_with_suffix(path, stamp, 0)
@@ -260,16 +459,17 @@ pub(super) fn conflict_path(path: &Path, stamp: i64) -> PathBuf {
 /// As [`conflict_path`], with a deterministic suffix used when that name already
 /// exists. This keeps conflict preservation from ever replacing an older copy.
 pub(super) fn conflict_path_with_suffix(path: &Path, stamp: i64, suffix: u32) -> PathBuf {
+    conflict_path_as(path, crate::conflict_label(), stamp, suffix)
+}
+
+/// [`conflict_path_with_suffix`] with the machine's label given.
+pub(super) fn conflict_path_as(path: &Path, label: &str, stamp: i64, suffix: u32) -> PathBuf {
     let stem = path.file_stem().and_then(|s| s.to_str()).unwrap_or("file");
     let ext = path.extension().and_then(|s| s.to_str());
-    let suffix = if suffix == 0 {
-        String::new()
-    } else {
-        format!("-{suffix}")
-    };
+    let tag = crate::conflict_tag(label, stamp, suffix);
     let name = match ext {
-        Some(ext) => format!("{stem} (sync-conflict {stamp}{suffix}).{ext}"),
-        None => format!("{stem} (sync-conflict {stamp}{suffix})"),
+        Some(ext) => format!("{stem} (sync-conflict {tag}).{ext}"),
+        None => format!("{stem} (sync-conflict {tag})"),
     };
     match path.parent() {
         Some(dir) => dir.join(name),
@@ -290,11 +490,14 @@ pub(super) enum FilePlan {
     DeleteLocal,
     DeleteRemote,
     ForgetBaseline,
-    /// First sync of a file that already exists on both sides with identical
-    /// content: record the baseline without transferring anything. Without this,
+    /// First sync of a file that exists on both sides at the same size, with a
+    /// digest on Drive: record the baseline without transferring anything if
+    /// the local file hashes the same, else keep a conflict copy. Without this,
     /// a folder synced for the first time cuts a `(sync-conflict)` copy of every
     /// pre-existing file, because a missing baseline makes both sides read as
-    /// "changed" (see the mass first-sync conflict storm in docs/BUGS.md).
+    /// "changed" (see the mass first-sync conflict storm in docs/BUGS.md). Size
+    /// alone is not enough: a second machine joining the folder would read a
+    /// different file of the same size as in step (B248).
     AdoptBaseline,
 }
 
@@ -313,8 +516,13 @@ pub(super) fn plan_file(
         // left the file the same length, so it was never uploaded.
         baseline.is_none_or(|base| !LocalSig::from(item).same_content(&LocalSig::from(base)))
     });
+    // Another client's new revision shows in its id even when the link's
+    // modification time and the size come out the same.
     let remote_changed = remote.is_some_and(|item| {
-        baseline.is_none_or(|base| remote_sig(base) != Some((item.mtime, item.size)))
+        baseline.is_none_or(|base| {
+            remote_sig(base) != Some((item.mtime, item.size))
+                || revision_moved(Some(base), item.revision.as_deref())
+        })
     });
 
     match (local, remote) {
@@ -324,10 +532,13 @@ pub(super) fn plan_file(
             (false, true) => FilePlan::Download,
             // With a baseline, both-changed is a genuine concurrent edit and must
             // be preserved as a conflict. Without one, "both changed" only means
-            // this is the first sync and there was nothing to compare to: adopt
-            // the baseline when the sizes already match rather than conflict-copy
-            // an already-identical file. Divergent sizes stay a real conflict.
-            (true, true) if baseline.is_none() && l.size == r.size => FilePlan::AdoptBaseline,
+            // this is the first sync and there was nothing to compare to: when the
+            // sizes match and Drive has a digest to compare against, the apply
+            // step hashes the local file before adopting it. Divergent sizes, or
+            // no digest, stay a real conflict: a missing digest proves nothing.
+            (true, true) if baseline.is_none() && l.size == r.size && r.sha1.is_some() => {
+                FilePlan::AdoptBaseline
+            }
             (true, true) => FilePlan::Conflict,
         },
         (Some(_), None) if baseline.is_none() || local_changed => FilePlan::UploadNew,
@@ -359,6 +570,8 @@ mod file_plan_tests {
             is_dir: false,
             mtime,
             size,
+            revision: None,
+            sha1: None,
         }
     }
 
@@ -376,6 +589,7 @@ mod file_plan_tests {
             local_size,
             remote_rev: Some(remote_mtime.to_string()),
             remote_hash: Some(remote_size.to_string()),
+            remote_revision_id: None,
         }
     }
 
@@ -497,12 +711,28 @@ mod file_plan_tests {
     fn first_sync_of_an_identical_file_adopts_the_baseline_not_a_conflict() {
         // No baseline yet (first sync). Same size on both sides is a pre-existing
         // identical file, not a concurrent edit: adopt it rather than cut a
-        // conflict copy of every file in the folder.
+        // conflict copy of every file in the folder. The apply step still
+        // hashes the local file before it records anything.
+        let local = local(10, 40);
+        let remote = RemoteItem {
+            sha1: Some("da39a3ee".into()),
+            ..remote(30, 40)
+        };
+        assert_eq!(
+            plan_file(Some(&local), Some(&remote), None),
+            FilePlan::AdoptBaseline
+        );
+    }
+
+    /// A file on Drive without a digest cannot be compared without a download,
+    /// and the same size is not the same content (B248).
+    #[test]
+    fn first_sync_without_a_remote_digest_is_a_conflict() {
         let local = local(10, 40);
         let remote = remote(30, 40);
         assert_eq!(
             plan_file(Some(&local), Some(&remote), None),
-            FilePlan::AdoptBaseline
+            FilePlan::Conflict
         );
     }
 
@@ -518,6 +748,73 @@ mod file_plan_tests {
         );
     }
 
+    /// Another computer's new revision can leave the modification time and
+    /// the size as they were. The revision id still tells it apart (B249).
+    #[test]
+    fn a_new_remote_revision_is_a_change_even_at_the_same_mtime_and_size() {
+        let mut base = baseline(10, 20, 30, 40);
+        base.remote_revision_id = Some("r1".into());
+        let unedited = local(10, 20);
+        let same = RemoteItem {
+            revision: Some("r1".into()),
+            ..remote(30, 40)
+        };
+        let newer = RemoteItem {
+            revision: Some("r2".into()),
+            ..remote(30, 40)
+        };
+        assert_eq!(
+            plan_file(Some(&unedited), Some(&same), Some(&base)),
+            FilePlan::Unchanged
+        );
+        assert_eq!(
+            plan_file(Some(&unedited), Some(&newer), Some(&base)),
+            FilePlan::Download
+        );
+        let edited = local(11, 20);
+        assert_eq!(
+            plan_file(Some(&edited), Some(&newer), Some(&base)),
+            FilePlan::Conflict
+        );
+
+        // A row from before schema 44 has no id to compare, and a node read
+        // without one says nothing: both fall back to the signature.
+        let old = baseline(10, 20, 30, 40);
+        assert_eq!(
+            plan_file(Some(&unedited), Some(&newer), Some(&old)),
+            FilePlan::Unchanged
+        );
+        assert_eq!(
+            plan_file(Some(&unedited), Some(&remote(30, 40)), Some(&base)),
+            FilePlan::Unchanged
+        );
+    }
+
+    /// The walk reuses the recorded size only while the revision is the one
+    /// the baseline holds.
+    #[test]
+    fn a_moved_revision_makes_the_walk_read_the_size_again() {
+        let mut base = baseline(10, 20, 30, 40);
+        base.remote_revision_id = Some("r1".into());
+        let rows = HashMap::from([("file".to_string(), base)]);
+        assert_eq!(
+            unchanged_remote_size(&rows, "file", 30, Some("r1")),
+            Some(40)
+        );
+        assert_eq!(unchanged_remote_size(&rows, "file", 30, None), Some(40));
+        assert_eq!(unchanged_remote_size(&rows, "file", 30, Some("r2")), None);
+        assert_eq!(unchanged_remote_size(&rows, "file", 31, Some("r1")), None);
+    }
+
+    /// A row without a revision id reuses its size only while Drive gives no
+    /// id either (B254).
+    #[test]
+    fn a_row_without_a_revision_makes_the_walk_read_the_size_again() {
+        let rows = HashMap::from([("file".to_string(), baseline(10, 20, 30, 40))]);
+        assert_eq!(unchanged_remote_size(&rows, "file", 30, Some("r1")), None);
+        assert_eq!(unchanged_remote_size(&rows, "file", 30, None), Some(40));
+    }
+
     #[test]
     fn a_missing_remote_signature_is_treated_as_changed() {
         let local = local(10, 20);
@@ -530,4 +827,153 @@ mod file_plan_tests {
             FilePlan::Download
         );
     }
+
+    fn uid(id: &str) -> NodeUid {
+        NodeUid::new(VolumeId::from("v"), LinkId::from(id))
+    }
+
+    fn folder() -> RemoteItem {
+        RemoteItem {
+            is_dir: true,
+            mtime: 0,
+            size: 0,
+            ..remote(0, 0)
+        }
+    }
+
+    /// An empty or failed remote listing must not read as "Drive deleted
+    /// everything" and delete the local copies.
+    #[test]
+    fn the_remote_wipe_guard_blocks_a_total_disappearance() {
+        let base = HashMap::from([("a".to_string(), ()), ("b".to_string(), ())]);
+        let none: HashMap<String, RemoteItem> = HashMap::new();
+        assert!(guard_remote_wipe(&base, &none).is_err());
+        let one = HashMap::from([("b".to_string(), remote(1, 1))]);
+        assert!(guard_remote_wipe(&base, &one).is_ok());
+        let empty: HashMap<String, ()> = HashMap::new();
+        assert!(guard_remote_wipe(&empty, &none).is_ok());
+    }
+
+    /// One path left of a large folder no longer clears either guard: most
+    /// of it gone at once is a lost tree, not a cleanup (B270).
+    #[test]
+    fn one_survivor_of_a_large_folder_does_not_clear_the_wipe_guards() {
+        let base: HashMap<String, ()> = (0..40).map(|n| (format!("f{n}.txt"), ())).collect();
+        let survivors = |n: usize| -> HashMap<String, ()> {
+            (0..n).map(|n| (format!("f{n}.txt"), ())).collect()
+        };
+        assert!(guard_local_wipe(&base, &survivors(1)).is_err());
+        assert!(guard_remote_wipe(&base, &survivors(1)).is_err());
+        // 36 of 40 gone is nine tenths: still refused.
+        assert!(guard_local_wipe(&base, &survivors(4)).is_err());
+        // 35 of 40 gone is under nine tenths: a pass may delete that much.
+        assert!(guard_local_wipe(&base, &survivors(5)).is_ok());
+        assert!(guard_remote_wipe(&base, &survivors(5)).is_ok());
+        let reason = guard_local_wipe(&base, &survivors(1)).unwrap_err();
+        assert!(reason.starts_with("39 of the 40 synced paths"), "{reason}");
+    }
+
+    /// A small folder still loses most of its files to an ordinary cleanup, so
+    /// only a total loss stops it.
+    #[test]
+    fn a_small_folder_trips_the_wipe_guards_only_when_everything_is_gone() {
+        let base: HashMap<String, ()> = (0..19).map(|n| (format!("f{n}.txt"), ())).collect();
+        let one: HashMap<String, ()> = [("f0.txt".to_string(), ())].into_iter().collect();
+        assert!(guard_local_wipe(&base, &one).is_ok());
+        assert!(guard_remote_wipe(&base, &one).is_ok());
+        let none: HashMap<String, ()> = HashMap::new();
+        assert!(guard_local_wipe(&base, &none).is_err());
+    }
+
+    /// A node that failed to decrypt has no name, so everything a short
+    /// listing did not return is left out, and nothing else.
+    #[test]
+    fn a_short_remote_listing_hides_what_it_did_not_return() {
+        let remote = HashMap::from([
+            ("docs".to_string(), folder()),
+            ("docs/a.txt".to_string(), remote(1, 1)),
+            ("pics".to_string(), folder()),
+        ]);
+        let dirs = HashMap::from([
+            (String::new(), uid("root")),
+            ("docs".to_string(), uid("docs")),
+            ("pics".to_string(), uid("pics")),
+        ]);
+        let mut gaps = RemoteGaps::default();
+        assert!(!gaps.hides("docs/b.txt", &remote, &dirs));
+        gaps.short_listing("docs");
+        // Returned paths stand; unreturned ones under the short folder hide,
+        // and so does anything under a subfolder it failed to return.
+        assert!(!gaps.hides("docs/a.txt", &remote, &dirs));
+        assert!(gaps.hides("docs/b.txt", &remote, &dirs));
+        assert!(gaps.hides("docs/sub/deep.txt", &remote, &dirs));
+        // A complete sibling listing still reads deletions as deletions.
+        assert!(!gaps.hides("pics/gone.jpg", &remote, &dirs));
+        assert!(!gaps.hides("top.txt", &remote, &dirs));
+        gaps.short_listing("");
+        assert!(gaps.hides("top.txt", &remote, &dirs));
+    }
+
+    /// A folder whose listing failed was walked no further: nothing under it
+    /// reads as deleted on Drive, and a sibling that listed still does
+    /// (`docs/BUGS.md` B271).
+    #[test]
+    fn a_folder_that_failed_to_list_hides_everything_under_it() {
+        let remote = HashMap::from([
+            ("docs".to_string(), folder()),
+            ("pics".to_string(), folder()),
+        ]);
+        let dirs = HashMap::from([
+            (String::new(), uid("root")),
+            ("docs".to_string(), uid("docs")),
+            ("pics".to_string(), uid("pics")),
+        ]);
+        let mut gaps = RemoteGaps::default();
+        gaps.unlisted("docs");
+        assert!(gaps.hides("docs/a.txt", &remote, &dirs));
+        assert!(gaps.hides("docs/sub/deep.txt", &remote, &dirs));
+        assert!(!gaps.hides("docs", &remote, &dirs));
+        assert!(!gaps.hides("pics/gone.jpg", &remote, &dirs));
+        assert_eq!(
+            gaps.report(),
+            ["docs (could not be listed on Proton Drive; tried again next pass)"]
+        );
+    }
+
+    #[test]
+    fn a_file_whose_size_could_not_be_read_is_hidden() {
+        let remote: HashMap<String, RemoteItem> = HashMap::new();
+        let dirs = HashMap::from([(String::new(), uid("root"))]);
+        let mut gaps = RemoteGaps::default();
+        gaps.unread("a.txt".to_string());
+        assert!(gaps.hides("a.txt", &remote, &dirs));
+        assert!(!gaps.hides("b.txt", &remote, &dirs));
+        assert_eq!(gaps.report(), ["a.txt (cannot be read on Proton Drive)"]);
+    }
+
+    /// A folder deleted here holds another device's new work on Drive, so
+    /// trashing it would lose that work.
+    #[test]
+    fn a_remote_folder_with_new_or_changed_files_is_not_trashed() {
+        let mut base = HashMap::from([
+            ("x".to_string(), baseline(0, 0, 0, 0)),
+            ("x/old.txt".to_string(), baseline(1, 1, 5, 6)),
+        ]);
+        let mut remote_tree = HashMap::from([
+            ("x".to_string(), folder()),
+            ("x/old.txt".to_string(), remote(5, 6)),
+            ("xy/new.txt".to_string(), remote(1, 1)),
+        ]);
+        // Unchanged under x; a name-prefixed sibling does not count.
+        assert_eq!(remote_subtree_changed("x", &remote_tree, &base), None);
+
+        remote_tree.insert("x/old.txt".to_string(), remote(9, 6));
+        assert!(remote_subtree_changed("x", &remote_tree, &base).is_some());
+
+        remote_tree.insert("x/old.txt".to_string(), remote(5, 6));
+        remote_tree.insert("x/sub".to_string(), folder());
+        assert!(remote_subtree_changed("x", &remote_tree, &base).is_some());
+        base.insert("x/sub".to_string(), baseline(0, 0, 0, 0));
+        assert_eq!(remote_subtree_changed("x", &remote_tree, &base), None);
+    }
 }

crates/pdfs-fuse/src/systemd.rs

@@ -64,11 +64,19 @@ fn send_abstract(socket: &UnixDatagram, name: &str, message: &str) -> bool {
 /// so `systemctl --user start` returns when the mount actually works rather than
 /// when the process exists.
 pub(crate) fn ready() {
-    if notify("READY=1\n") {
+    if notify("READY=1\nSTATUS=Mounted\n") {
         debug!("notified systemd: ready");
     }
 }
 
+/// Set the one-line status `systemctl --user status` shows for the unit, such
+/// as why the mount keeps failing (`docs/BUGS.md` B263).
+pub fn status(text: &str) {
+    // A newline would end the `STATUS=` line and start another variable.
+    let line = text.replace('\n', " ");
+    notify(&format!("STATUS={line}\n"));
+}
+
 /// Tell the manager the daemon is still healthy.
 pub(crate) fn watchdog_ping() {
     let _ = notify("WATCHDOG=1\n");
@@ -94,6 +102,37 @@ pub fn idle_sleep(duration: Duration) {
     }
 }
 
+/// How long a mount may take to start before the watchdog counts it as hung.
+///
+/// Startup has no control socket to probe yet, and on a large account it is
+/// long: hydrating 48 000 nodes took 70 s on 2026-11-12, and the secondary
+/// mounts followed. Under the 2-minute `WatchdogSec` that run was aborted just
+/// before its first ping, and left six dead mounts behind (`docs/BUGS.md` B279).
+const STARTUP_WATCHDOG: Duration = Duration::from_secs(600);
+
+/// Give the mount about to start [`STARTUP_WATCHDOG`] before the watchdog fires.
+///
+/// Sends `WATCHDOG_USEC=`, which replaces the unit's timeout and restarts its
+/// timer. The supervisor puts the configured timeout back with
+/// [`restore_watchdog`] once it can prove the daemon answers. A startup that
+/// wedges for good is still aborted, only later.
+pub fn stretch_watchdog_for_startup() {
+    if watchdog_period().is_some() {
+        notify(&format!("WATCHDOG_USEC={}\n", STARTUP_WATCHDOG.as_micros()));
+    }
+}
+
+/// Put back the timeout the unit configured, undoing
+/// [`stretch_watchdog_for_startup`].
+pub(crate) fn restore_watchdog() {
+    if watchdog_period().is_none() {
+        return;
+    }
+    if let Ok(usec) = std::env::var("WATCHDOG_USEC") {
+        notify(&format!("WATCHDOG_USEC={usec}\n"));
+    }
+}
+
 /// Tell the manager the daemon is stopping, so a slow teardown is not mistaken
 /// for a hang by the watchdog it is racing.
 pub(crate) fn stopping() {

crates/pdfs-fuse/src/takeout.rs

@@ -25,7 +25,7 @@ use std::collections::{BTreeMap, HashMap};
 use std::io::Read;
 use std::path::PathBuf;
 use std::sync::Arc;
-use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
 
 use pdfs_core::control::{ActivityKind, ImportSummary, TransferDirection};
 use pdfs_core::takeout::{Bucket, TakeoutPhoto, TakeoutScan, scan_archives};
@@ -36,6 +36,7 @@ use sha1::{Digest, Sha1};
 use tracing::{info, warn};
 
 use super::Core;
+use crate::photos::can_make_thumbnail;
 use crate::transfers::CountingReader;
 
 /// The one import this daemon may be running, and how the last one ended.
@@ -136,6 +137,30 @@ fn read_entry<R>(
 }
 
 impl Core {
+    /// Copy archive entry `entry` into the thumbnail staging folder and return
+    /// its path. The caller removes it.
+    fn stage_takeout_entry(
+        &self,
+        archive: &mut zip::ZipArchive<std::io::BufReader<std::fs::File>>,
+        entry: &str,
+    ) -> CoreResult<PathBuf> {
+        static STAGED: AtomicU64 = AtomicU64::new(0);
+        let path = self.cache.raw_thumbnail_staging_dir().join(format!(
+            "takeout-{}-{}",
+            std::process::id(),
+            STAGED.fetch_add(1, Ordering::Relaxed)
+        ));
+        let copied = read_entry(archive, entry, |reader| {
+            let mut file = std::fs::File::create(&path)?;
+            std::io::copy(reader, &mut file)
+        })?;
+        if let Err(e) = copied {
+            let _ = std::fs::remove_file(&path);
+            return Err(CoreError::internal(format!("copy {entry}: {e}")));
+        }
+        Ok(path)
+    }
+
     /// Import Google Photos Takeout archives. Blocking; run on its own thread.
     ///
     /// `cancel` stops the run at the next photo boundary — an upload already on
@@ -319,20 +344,73 @@ impl Core {
                 );
                 let metadata = PhotoUploadMetadata {
                     capture_time: photo.capture_time,
+                    last_modification_time: photo
+                        .capture_time
+                        .and_then(pdfs_core::timestamp::modification_time),
                     ..Default::default()
                 };
-                let uploaded = read_entry(&mut archive, &photo.entry, |reader| {
-                    let counting = CountingReader::new(reader, &guard);
-                    self.rt.block_on(photos.upload_photo_from(
-                        &photo.name,
-                        &photo.media_type,
-                        counting,
-                        photo.size as i64,
-                        Vec::new(),
-                        metadata,
-                        false,
-                    ))
-                });
+                // A thumbnail is made from a file, so a photo that can have one
+                // is copied out of the archive first and uploaded from the copy.
+                // Without one, Proton's apps show a blank tile until they make
+                // their own.
+                let staged = can_make_thumbnail(&photo.name, photo.size)
+                    .then(|| self.stage_takeout_entry(&mut archive, &photo.entry))
+                    .and_then(|staged| {
+                        staged
+                            .inspect_err(|e| {
+                                warn!(name = photo.name, error = %e,
+                                      "copying a takeout photo out failed; uploading it without a thumbnail")
+                            })
+                            .ok()
+                    });
+                let uploaded = match &staged {
+                    Some(path) => {
+                        let thumbnails = self.upload_thumbnails(path, &photo.name);
+                        // No sidecar and no date in the name: the photo's own
+                        // EXIF, before Drive files it under today.
+                        let capture_time = metadata
+                            .capture_time
+                            .or_else(|| pdfs_core::exiftime::capture_time_of(path));
+                        let metadata = PhotoUploadMetadata {
+                            capture_time,
+                            last_modification_time: capture_time
+                                .and_then(pdfs_core::timestamp::modification_time),
+                            ..metadata
+                        };
+                        std::fs::File::open(path)
+                            .map_err(|e| {
+                                CoreError::internal(format!("open {}: {e}", path.display()))
+                            })
+                            .map(|file| {
+                                let counting =
+                                    CountingReader::new(std::io::BufReader::new(file), &guard);
+                                self.rt.block_on(photos.upload_photo_from(
+                                    &photo.name,
+                                    &photo.media_type,
+                                    counting,
+                                    photo.size as i64,
+                                    thumbnails,
+                                    metadata,
+                                    false,
+                                ))
+                            })
+                    }
+                    None => read_entry(&mut archive, &photo.entry, |reader| {
+                        let counting = CountingReader::new(reader, &guard);
+                        self.rt.block_on(photos.upload_photo_from(
+                            &photo.name,
+                            &photo.media_type,
+                            counting,
+                            photo.size as i64,
+                            Vec::new(),
+                            metadata,
+                            false,
+                        ))
+                    }),
+                };
+                if let Some(path) = staged {
+                    let _ = std::fs::remove_file(path);
+                }
                 drop(guard);
                 job.step();
 
@@ -480,7 +558,15 @@ impl Core {
                 let mut state = IMPORT.lock();
                 state.running = false;
                 state.cancel = None;
-                state.last = outcome.as_ref().ok().cloned();
+                // A failed run is reported too: without it, `--wait` read
+                // "no import has run" and exited as if all was well.
+                state.last = Some(match &outcome {
+                    Ok(summary) => summary.clone(),
+                    Err(e) => ImportSummary {
+                        error: Some(e.to_string()),
+                        ..Default::default()
+                    },
+                });
             }
             match outcome {
                 Ok(summary) => {
@@ -545,7 +631,7 @@ pub(crate) fn sha1_of(reader: &mut (dyn Read + Send)) -> CoreResult<String> {
     Ok(hex_lower(&hasher.finalize()))
 }
 
-fn hex_lower(bytes: &[u8]) -> String {
+pub(crate) fn hex_lower(bytes: &[u8]) -> String {
     let mut out = String::with_capacity(bytes.len() * 2);
     for byte in bytes {
         out.push_str(&format!("{byte:02x}"));

crates/pdfs-fuse/src/transfers.rs

@@ -125,6 +125,11 @@ impl TransferRegistry {
         self.download_limit.set(download);
     }
 
+    /// The upload cap in bytes per second, `0` when there is none.
+    pub fn upload_cap(&self) -> u64 {
+        self.upload_limit.rate.load(Ordering::Relaxed)
+    }
+
     fn limit(&self, direction: TransferDirection) -> &RateLimit {
         match direction {
             TransferDirection::Upload => &self.upload_limit,

crates/pdfs-gui/Cargo.toml

@@ -40,4 +40,4 @@ pangocairo = "0.22"
 # Map tiles for the opt-in online map. The same build proton-sdk already pulls in.
 reqwest = { version = "0.13", default-features = false, features = ["rustls", "webpki-roots"] }
 # The system libintl (glibc) rather than a bundled gettext build.
-gettext-rs = { version = "0.7", features = ["gettext-system"] }
+gettext-rs = { version = "0.8", features = ["gettext-system"] }

crates/pdfs-gui/resources/icons/scalable/actions/pdfs-album-symbolic.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
+  <!-- Album: a photo in front of the edge of another, a stack of them. -->
+  <path fill="#222222" d="M 4,1 H 13.5 A 1.5,1.5 0 0 1 15,2.5 V 12 H 13.5 V 2.5 H 4 Z"/>
+  <path fill="#222222" fill-rule="evenodd" d="M 2.5,4 H 10.5 A 1.5,1.5 0 0 1 12,5.5 V 13.5 A 1.5,1.5 0 0 1 10.5,15 H 2.5 A 1.5,1.5 0 0 1 1,13.5 V 5.5 A 1.5,1.5 0 0 1 2.5,4 Z M 2.5,5.5 V 13.5 H 10.5 V 5.5 Z"/>
+  <path fill="#222222" d="M 3.5,12.5 L 5.5,9.2 L 7.2,11.2 L 8.2,10.2 L 9.5,12.5 Z"/>
+</svg>

crates/pdfs-gui/resources/icons/scalable/actions/pdfs-photos-symbolic.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
+  <!-- Photos: a framed landscape with a sun. Stock themes only have
+       image-x-generic, a file type icon, which reads as "an image file"
+       rather than "your photo library". -->
+  <path fill="#222222" fill-rule="evenodd" d="M 3,2 H 13 A 2,2 0 0 1 15,4 V 12 A 2,2 0 0 1 13,14 H 3 A 2,2 0 0 1 1,12 V 4 A 2,2 0 0 1 3,2 Z M 3,3.5 A 0.5,0.5 0 0 0 2.5,4 V 12 A 0.5,0.5 0 0 0 3,12.5 H 13 A 0.5,0.5 0 0 0 13.5,12 V 4 A 0.5,0.5 0 0 0 13,3.5 Z"/>
+  <path fill="#222222" d="M 3.5,11.5 L 6.5,7 L 9,10.2 L 10.5,8.6 L 12.5,11.5 Z"/>
+  <circle fill="#222222" cx="10.5" cy="5.8" r="1.3"/>
+</svg>

crates/pdfs-gui/resources/icons/scalable/actions/pdfs-slideshow-symbolic.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
+  <!-- Slideshow: a play mark inside a photo frame, so it is not mistaken for
+       playing the video on screen. -->
+  <path fill="#222222" fill-rule="evenodd" d="M 3,2 H 13 A 2,2 0 0 1 15,4 V 12 A 2,2 0 0 1 13,14 H 3 A 2,2 0 0 1 1,12 V 4 A 2,2 0 0 1 3,2 Z M 3,3.5 A 0.5,0.5 0 0 0 2.5,4 V 12 A 0.5,0.5 0 0 0 3,12.5 H 13 A 0.5,0.5 0 0 0 13.5,12 V 4 A 0.5,0.5 0 0 0 13,3.5 Z"/>
+  <path fill="#222222" d="M 6.5,5.2 L 11,8 L 6.5,10.8 Z"/>
+</svg>

crates/pdfs-gui/resources/pdfs.gresource.xml

@@ -15,6 +15,9 @@
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-link-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-map-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-people-symbolic.svg</file>
+    <file preprocess="xml-stripblanks">scalable/actions/pdfs-photos-symbolic.svg</file>
+    <file preprocess="xml-stripblanks">scalable/actions/pdfs-album-symbolic.svg</file>
+    <file preprocess="xml-stripblanks">scalable/actions/pdfs-slideshow-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-share-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-sync-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-synced-symbolic.svg</file>

crates/pdfs-gui/resources/style.css

@@ -53,7 +53,7 @@ button.sidebar-account { padding: 4px 8px; font-weight: normal; }
 /* The folder on screen, last in the breadcrumb trail: a flat button's side
  * padding, so the "›" before it is spaced like the ones between buttons. */
 .crumb-current { padding: 0 10px; }
-scale.browser-status-meter trough { min-width: 104px; min-height: 6px; }
+scale.browser-status-meter trough { min-width: 140px; min-height: 6px; }
 .bulk-bar { padding: 6px 8px; border-radius: 12px; background: color-mix(in srgb, var(--accent-bg-color) 12%, transparent); }
 .dropzone { border: 2px dashed alpha(currentColor, 0.25); border-radius: 16px; padding: 28px 18px; transition: background 160ms ease, border-color 160ms ease; }
 .dropzone-active { border-color: var(--accent-bg-color); background: color-mix(in srgb, var(--accent-bg-color) 10%, transparent); }
@@ -61,14 +61,25 @@ scale.browser-status-meter trough { min-width: 104px; min-height: 6px; }
 
 /* Photo viewer: always light-on-dark, whatever the system style */
 .photo-viewer-window { background-color: #111014; }
-.viewer-top-bar { background: linear-gradient(to bottom, rgba(0, 0, 0, 0.75), rgba(0, 0, 0, 0)); padding: 10px 16px 28px 20px; color: white; }
+.viewer-top-bar { background: linear-gradient(to bottom, rgba(0, 0, 0, 0.85), rgba(0, 0, 0, 0.45) 60%, rgba(0, 0, 0, 0)); padding: 10px 16px 40px 20px; color: white; }
 .viewer-title { font-weight: 700; font-size: 1.05rem; text-shadow: 0 1px 3px rgba(0, 0, 0, 0.9); color: white; }
 .viewer-counter { font-size: 0.8rem; color: rgba(255, 255, 255, 0.72); text-shadow: 0 1px 3px rgba(0, 0, 0, 0.9); }
-.viewer-action-btn { color: white; background-color: rgba(255, 255, 255, 0.12); border-radius: 50%; min-width: 34px; min-height: 34px; margin-left: 4px; }
-.viewer-action-btn:hover { background-color: rgba(255, 255, 255, 0.28); color: white; }
+/* Dark discs with a white glyph read on a white photo as well as on a black one. */
+.viewer-action-btn { color: white; background-color: rgba(0, 0, 0, 0.5); border-radius: 50%; min-width: 36px; min-height: 36px; margin-left: 4px; -gtk-icon-shadow: 0 1px 2px rgba(0, 0, 0, 0.6); }
+.viewer-action-btn:hover { background-color: rgba(0, 0, 0, 0.75); color: white; }
 .viewer-action-btn:checked { background-color: var(--accent-bg-color); color: var(--accent-fg-color); }
-.viewer-close-btn { background-color: rgba(255, 255, 255, 0.2); margin-left: 10px; }
+.viewer-close-btn { margin-left: 12px; }
 .viewer-close-btn:hover { background-color: var(--destructive-bg-color); color: var(--destructive-fg-color); }
+.viewer-group-pill { color: white; background-color: rgba(0, 0, 0, 0.5); border-radius: 999px; min-height: 36px; padding: 0 14px; font-weight: 700; font-size: 0.85rem; }
+.viewer-group-pill:hover { background-color: rgba(0, 0, 0, 0.75); color: white; }
+.viewer-group-pill.lit { background-color: var(--accent-bg-color); color: var(--accent-fg-color); }
+/* The thumbnail strip along the lightbox's bottom edge, the photo on screen ringed in the accent. */
+.viewer-strip-bar { background: linear-gradient(to top, rgba(0, 0, 0, 0.8), rgba(0, 0, 0, 0)); padding: 28px 12px 10px 12px; }
+.viewer-strip { background: none; }
+.viewer-strip > row { padding: 2px; margin: 0 2px; border-radius: 8px; background: none; }
+.viewer-strip > row:hover { background-color: rgba(255, 255, 255, 0.15); }
+.viewer-strip > row:selected { background-color: var(--accent-bg-color); }
+.viewer-strip-thumb { border-radius: 6px; background-color: rgba(255, 255, 255, 0.08); }
 .viewer-nav-btn { background-color: rgba(0, 0, 0, 0.45); color: white; margin: 20px; min-width: 44px; min-height: 44px; border-radius: 50%; opacity: 0.7; transition: opacity 150ms ease, background-color 150ms ease; }
 .viewer-nav-btn:hover { background-color: rgba(0, 0, 0, 0.85); color: white; opacity: 1; }
 .viewer-nav-btn:disabled { opacity: 0; }
@@ -80,7 +91,12 @@ scale.browser-status-meter trough { min-width: 104px; min-height: 6px; }
 .viewer-info-panel { background-color: var(--window-bg-color); border-left: 1px solid alpha(currentColor, 0.12); }
 
 /* Photos grid */
-.gallery-day { font-size: 0.82rem; font-weight: 700; letter-spacing: 0.04em; text-transform: uppercase; color: alpha(currentColor, 0.65); padding: 2px 2px 6px 2px; }
+.gallery-day { font-size: 1.1rem; font-weight: 700; padding: 4px 2px 8px 2px; }
+/* The check that picks a whole section: on hover, and always while selecting. */
+.gallery-day-check { opacity: 0; transition: opacity 160ms ease; min-width: 24px; min-height: 24px; margin-bottom: 4px; }
+.gallery-heading:hover .gallery-day-check, .gallery-heading.selecting .gallery-day-check, .gallery-day-check:focus-visible { opacity: 1; }
+/* The section at the top of the grid, floating once its heading scrolled off. */
+.gallery-float-heading { font-weight: 700; padding: 4px 12px; border-radius: 999px; background-color: color-mix(in srgb, var(--popover-bg-color) 92%, transparent); color: var(--popover-fg-color); box-shadow: 0 1px 4px rgba(0, 0, 0, 0.25); }
 .photo-tile { padding: 0; margin: 0; min-height: 0; min-width: 0; border: none; border-radius: 4px; background: none; box-shadow: none; }
 .photo-tile:focus { outline: 2px solid var(--accent-color); outline-offset: -2px; }
 .photo-thumb { transition: transform 220ms ease; }
@@ -94,6 +110,7 @@ scale.browser-status-meter trough { min-width: 104px; min-height: 6px; }
 .photo-video-badge { color: white; background: rgba(0, 0, 0, 0.45); border-radius: 999px; padding: 8px; min-width: 20px; min-height: 20px; box-shadow: 0 2px 8px rgba(0, 0, 0, 0.5); transition: background 160ms ease; }
 .photo-video-badge-small { padding: 3px; min-width: 0; min-height: 0; }
 .photo-tile:hover .photo-video-badge { background: color-mix(in srgb, var(--accent-bg-color) 85%, transparent); }
+.photo-favorite-badge { color: white; -gtk-icon-shadow: 0 1px 3px rgba(0, 0, 0, 0.9); }
 .photo-group-badge { font-size: 0.68rem; font-weight: 700; letter-spacing: 0.04em; color: white; background: rgba(0, 0, 0, 0.55); border-radius: 6px; padding: 1px 5px; margin: 6px; text-shadow: 0 1px 2px rgba(0, 0, 0, 0.9); }
 .memory-card { padding: 0; border-radius: 12px; }
 .memory-cover { border-radius: 12px; background: alpha(currentColor, 0.06); }
@@ -103,7 +120,7 @@ scale.browser-status-meter trough { min-width: 104px; min-height: 6px; }
 .album-cover { border-radius: 16px; background: alpha(currentColor, 0.06); box-shadow: 0 4px 16px rgba(0, 0, 0, 0.32); transition: box-shadow 180ms ease; }
 .album-card:hover .album-cover { box-shadow: 0 10px 26px rgba(0, 0, 0, 0.5); }
 .album-card:hover .photo-thumb { transform: scale(1.05); }
-.view-switch button, .view-switch toggle { padding-left: 18px; padding-right: 18px; }
+.view-switch button, .view-switch toggle { padding-left: 12px; padding-right: 12px; }
 
 /* Shared with Me: what a share lets me do, as a tinted pill beside the name. */
 .role-pill { padding: 2px 10px; border-radius: 999px; font-weight: 600; color: var(--accent-color); background-color: color-mix(in srgb, var(--accent-bg-color) 16%, transparent); }

crates/pdfs-gui/src/activation.rs

@@ -10,9 +10,14 @@
 //! `dead_code` allowances below are for — not code nobody uses.
 
 use std::path::{Path, PathBuf};
+use std::time::Duration;
 
 use pdfs_core::control::{PhotoKind, SearchHit};
 
+/// How long a `stat` of the mount may take before the file counts as not
+/// there. A frozen mount never answers, and every caller has a fallback.
+const STAT_TIMEOUT: Duration = Duration::from_secs(2);
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub(crate) enum DriveActivation {
     Folder,
@@ -55,18 +60,32 @@ pub(crate) fn mounted_target(mountpoint: &Path, hit: &SearchHit) -> Option<PathB
     present(mounted_or_relative(mountpoint, hit))
 }
 
-/// [`mounted_target`] for callers holding a mountpoint-relative path rather
-/// than a search hit — the browser's listing entries, which are by definition
-/// paths in the primary mount's tree.
-#[allow(dead_code)] // browser only
-pub(crate) fn mounted_target_rel(mountpoint: &Path, relative_path: &str) -> Option<PathBuf> {
-    present(mounted_path(mountpoint, relative_path))
-}
-
 fn present(path: PathBuf) -> Option<PathBuf> {
     path.symlink_metadata().is_ok().then_some(path)
 }
 
+/// Whether anything is at `path`, asked on a thread of its own and given up
+/// on after [`STAT_TIMEOUT`]. `None` means "not there" or "no answer".
+///
+/// For the GTK binaries, whose main thread must not `stat` the mount: a
+/// mount that hangs hung the whole window with it. The thread of a `stat`
+/// that never returns is left behind; there is no way to cancel one.
+#[allow(dead_code)] // GTK binaries only
+pub(crate) async fn present_within(path: PathBuf) -> Option<PathBuf> {
+    let (tx, rx) = async_channel::bounded(1);
+    std::thread::spawn(move || {
+        let _ = tx.send_blocking(present(path));
+    });
+    match gtk4::glib::future_with_timeout(STAT_TIMEOUT, rx.recv()).await {
+        Ok(Ok(target)) => target,
+        Ok(Err(_)) => None,
+        Err(_) => {
+            tracing::warn!("the mount did not answer in time");
+            None
+        }
+    }
+}
+
 /// The mount path for a hit, whether or not anything is there — for callers
 /// that have no fallback (a folder cannot be materialised) or already know the
 /// entry came from a mount listing.

crates/pdfs-gui/src/app/events.rs

@@ -128,8 +128,18 @@ fn follow_changes(ui: &Rc<Ui>, state: &FeedState, topics: &[Topic]) {
     if changed(Topic::Shares) {
         refresh_invitations_badge(ui, Duration::ZERO);
     }
-    match ui.stack.visible_child_name().as_deref() {
-        Some("browser") if changed(Topic::Files) => load_browser(ui),
+    let page = ui.stack.visible_child_name();
+    // A timeline out of sight is read again when the user comes back to it;
+    // one on screen is left alone (below).
+    if changed(Topic::Photos) && (page.as_deref() != Some("gallery") || !photo_grid_shown(ui)) {
+        ui.gallery.timeline_stale.set(true);
+    }
+    match page.as_deref() {
+        // A search on screen is left alone: reloading would swap its hits for
+        // the folder's listing while the query stays in the box.
+        Some("browser") if changed(Topic::Files) && ui.browser.search.text().trim().is_empty() => {
+            load_browser(ui)
+        }
         // The timeline is left alone: reloading it would throw away the place
         // the user scrolled to. F5 reloads it on request.
         Some("gallery")

crates/pdfs-gui/src/app/main.rs

@@ -10,6 +10,7 @@ pub(crate) mod pages;
 pub(crate) mod reload;
 #[path = "../theme.rs"]
 pub(crate) mod theme;
+pub(crate) mod update;
 pub(crate) mod widgets;
 
 use compat::*;
@@ -33,6 +34,7 @@ use pages::trash::*;
 use pages::verify::*;
 use reload::{LoadTicket, Loader, replace_items};
 use theme::{load_resources, proton_theme_active, set_proton_theme};
+use update::*;
 use widgets::compat::*;
 use widgets::crumb::*;
 use widgets::details::*;
@@ -69,15 +71,15 @@ use gtk4::glib::BoxedAnyObject;
 
 use pdfs_core::auth;
 
-use pdfs_core::config::{AppDirs, FileSort, FilesView};
+use pdfs_core::config::{AppDirs, FileSort, FilesView, PhotosView, WindowState};
 
 use pdfs_core::control::{
     ActivityEntry, ActivityKind, AlbumInfo, BookmarkInfo, ConflictInfo, ConflictKeep, DeviceInfo,
-    DirEntry, ErrorKind, ImportSummary, InvitationInfo, JobItem, MappingProgress, PendingOpInfo,
-    PhotoItem, PhotoKind, PhotoMonth, PlaceInfo, PublicLinkInfo, RefreshScope, Request, Response,
-    RestorableFolder, RestoreItem, RevisionInfo, SearchHit, ShareEntry, ShareEntryKind, SharedItem,
-    SyncFolderInfo, SyncIssue, SyncPhase, SyncProgress, ThumbnailBuildStatus, Topic,
-    TransferDirection, TransferItem, send,
+    DirEntry, ErrorKind, ImportSummary, InvitationInfo, JobItem, LinkChange, MappingProgress,
+    PendingOpInfo, PhotoItem, PhotoKind, PhotoMonth, PlaceInfo, PublicLinkInfo, RefreshScope,
+    Request, Response, RestorableFolder, RestoreItem, RevisionInfo, SearchHit, ShareEntry,
+    ShareEntryKind, SharedItem, SyncFolderInfo, SyncIssue, SyncPhase, SyncProgress,
+    ThumbnailBuildStatus, Topic, TransferDirection, TransferItem, send,
 };
 
 use pdfs_core::mounts::{MountAccess, MountKind, MountMode, MountSpec};
@@ -123,6 +125,9 @@ struct Ui {
     /// Whether this run already asked for the mailbox password of a locked
     /// account, so a refresh never re-opens a dialog the user cancelled.
     unlock_offered: Cell<bool>,
+    /// The `since` of the run of mount failures whose "folder isn't empty"
+    /// dialog this run already showed, so a page reload never shows it again.
+    not_empty_offered: Cell<i64>,
     /// Whether the last refresh saw a live mount daemon. Gates the unpin buttons
     /// (which need the daemon to evict + re-hydrate) and every mutating action.
     mounted: RefCell<bool>,
@@ -130,8 +135,12 @@ struct Ui {
     /// the page stack; [`sync_sidebar`] mirrors navigation that starts elsewhere.
     sidebar: gtk4::ListBox,
     /// The sidebar/content split. Collapsed while signed out, so the login page
-    /// owns the whole window and no destination is reachable without a session.
+    /// owns the whole window and no destination is reachable without a session,
+    /// and while the window is [`narrow`](Self::narrow).
     nav: adw::NavigationSplitView,
+    /// The window is too narrow for the sidebar beside a page, so the two take
+    /// turns. Set by the narrow breakpoint; [`refresh`] reads it.
+    narrow: Cell<bool>,
     /// Shared thumbnails for ordinary image files outside the Photos gallery.
     /// One cache and request queue serves Files, search, Shared and Trash, so
     /// the same image is downloaded and decoded only once.
@@ -151,6 +160,7 @@ struct Ui {
     pub(crate) locations: LocationsState,
     pub(crate) activity: ActivityState,
     pub(crate) takeout: TakeoutState,
+    pub(crate) update: UpdateState,
 }
 
 impl Ui {
@@ -297,7 +307,10 @@ fn present_window(app: &adw::Application) {
 /// Spawn the tray icon process in the background.
 pub(crate) fn spawn_tray() {
     match Command::new("pdfs-tray").spawn() {
-        Ok(_) => tracing::info!("spawned `pdfs-tray`"),
+        Ok(child) => {
+            tracing::info!("spawned `pdfs-tray`");
+            pdfs_core::opener::reap(child);
+        }
         Err(e) => tracing::error!("failed to spawn `pdfs-tray`: {e}"),
     }
 }
@@ -318,7 +331,9 @@ fn build_window(app: &adw::Application) {
         tracing::warn!("cannot create the app's directories: {e}");
     }
 
-    let stack = adw::ViewStack::new();
+    // Not homogeneous: each page sets the window's minimum width only while it
+    // is shown, so the widest page does not hold every other one wide.
+    let stack = adw::ViewStack::builder().hhomogeneous(false).build();
     let (login_page, login_widgets) = build_login_page();
     let main_widgets = build_main_page();
     let (browser_page, browser_widgets) = build_browser_page();
@@ -336,8 +351,12 @@ fn build_window(app: &adw::Application) {
     login_frame.add_top_bar(&{
         let header = adw::HeaderBar::new();
         header.set_show_title(false);
+        // The split is collapsed while signed out; going "back" would only
+        // uncover a sidebar with nowhere to go.
+        header.set_show_back_button(false);
         header
     });
+    login_frame.add_top_bar(&login_widgets.keyring_banner);
     login_frame.set_content(Some(&login_page));
     stack.add_named(&login_frame, Some("login"));
     stack.add_named(&browser_page, Some("browser"));
@@ -352,7 +371,8 @@ fn build_window(app: &adw::Application) {
     // Sidebar: the signed-in destinations. Selecting a row swaps the page stack;
     // `sync_sidebar` pushes the other way when navigation happens elsewhere (e.g.
     // login lands on Files).
-    let (sidebar_page, sidebar_list) = build_sidebar(&main_widgets.footer);
+    let update = UpdateState::new();
+    let (sidebar_page, sidebar_list) = build_sidebar(&main_widgets.footer, &update.banner);
 
     // Every page brings its own header bar (see `page_frame`), so the content
     // side is the bare stack.
@@ -365,6 +385,8 @@ fn build_window(app: &adw::Application) {
         .content(&content_page)
         .min_sidebar_width(200.0)
         .max_sidebar_width(240.0)
+        // A narrow window opens on the page, not the sidebar.
+        .show_content(true)
         .build();
 
     // Toasts float over everything, so a report from a background action reaches
@@ -372,17 +394,23 @@ fn build_window(app: &adw::Application) {
     let toasts = adw::ToastOverlay::new();
     toasts.set_child(Some(&split));
 
+    let (startup_session, keyring_error) = match read_session() {
+        Ok(session) => (session, None),
+        Err(e) => (None, Some(e)),
+    };
     let ui = Rc::new(Ui {
         dirs,
         stack: stack.clone(),
         toasts: toasts.clone(),
         busy: Cell::new(0),
         opening: RefCell::new(HashSet::new()),
-        session: RefCell::new(auth::load().ok()),
+        session: RefCell::new(startup_session),
         unlock_offered: Cell::new(false),
+        not_empty_offered: Cell::new(0),
         mounted: RefCell::new(false),
         sidebar: sidebar_list.clone(),
         nav: split.clone(),
+        narrow: Cell::new(false),
         file_thumbs: FileThumbnailState::new(),
         login: login_widgets,
         status: StatusState {
@@ -412,6 +440,7 @@ fn build_window(app: &adw::Application) {
             theme_row: main_widgets.theme_row.clone(),
             online_map_row: main_widgets.online_map_row.clone(),
             tray_row: main_widgets.tray_row.clone(),
+            update_row: main_widgets.update_row.clone(),
             language_row: main_widgets.language_row.clone(),
             settings_suppress: Cell::new(false),
             budget_source: RefCell::new(None),
@@ -428,6 +457,8 @@ fn build_window(app: &adw::Application) {
             files: browser_widgets.files.clone(),
             history: RefCell::new(Vec::new()),
             future: RefCell::new(Vec::new()),
+            places: RefCell::new(HashMap::new()),
+            restore: RefCell::new(None),
             crumb: browser_widgets.crumb.clone(),
             content: browser_widgets.content.clone(),
             status: browser_widgets.status.clone(),
@@ -459,6 +490,7 @@ fn build_window(app: &adw::Application) {
             empty_actions: browser_widgets.empty_actions.clone(),
             summary: browser_widgets.summary.clone(),
             zoom: browser_widgets.zoom.clone(),
+            zoom_save: RefCell::new(None),
         },
         details: DetailsState {
             details: browser_widgets.details,
@@ -538,6 +570,7 @@ fn build_window(app: &adw::Application) {
             reload_pending: Cell::new(false),
             loading: Cell::new(false),
             has_more: Cell::new(false),
+            library: Cell::new(true),
             page_waiters: RefCell::new(Vec::new()),
             width: Cell::new(0),
             photo_tex: RefCell::new(HashMap::new()),
@@ -557,10 +590,13 @@ fn build_window(app: &adw::Application) {
             selected: RefCell::new(HashSet::new()),
             select_anchor: RefCell::new(None),
             select_btn: gallery_widgets.select_btn.clone(),
-            select_bar: gallery_widgets.select_bar.clone(),
-            select_label: gallery_widgets.select_label.clone(),
-            select_trash: gallery_widgets.select_trash.clone(),
-            select_album: gallery_widgets.select_album.clone(),
+            selection: gallery_widgets.selection.clone(),
+            more: gallery_widgets.more.clone(),
+            upload_face: gallery_widgets.upload_face.clone(),
+            float_heading: gallery_widgets.float_heading.clone(),
+            float_label: gallery_widgets.float_label.clone(),
+            square: Cell::new(false),
+            zoom_save: RefCell::new(None),
         },
         shared: SharedState::new(&shared_widgets),
         shared_by_me: SharedByMeState::new(&shared_by_me_widgets),
@@ -580,6 +616,7 @@ fn build_window(app: &adw::Application) {
                 pause: locations_widgets.pause.clone(),
                 paused: Cell::new(false),
                 sign_in: locations_widgets.card_sign_in.clone(),
+                restart: locations_widgets.card_restart.clone(),
             },
             queue: QueueState {
                 group: locations_widgets.queue_group.clone(),
@@ -632,8 +669,12 @@ fn build_window(app: &adw::Application) {
             running: Cell::new(false),
             dry_run: Cell::new(false),
         },
+        update,
     });
     wire_login(&ui);
+    if let Some(e) = keyring_error {
+        keyring_unreadable(&ui, &e);
+    }
     let ui_status = ui.clone();
     main_widgets
         .status_button
@@ -658,7 +699,7 @@ fn build_window(app: &adw::Application) {
         &ui,
         &gallery_widgets.list,
         &gallery_widgets.scroll,
-        &gallery_widgets.select_done,
+        &gallery_widgets.square_action,
     );
     wire_gallery_empty(
         &ui,
@@ -675,6 +716,7 @@ fn build_window(app: &adw::Application) {
     wire_activity(&ui, &activity_widgets);
     wire_takeout(&ui, &takeout_widgets);
     wire_retry(&ui);
+    wire_update(&ui);
 
     // Lazily load the Files / Photos pages the first time they're shown, so the
     // network round-trip only happens on demand rather than on every refresh.
@@ -686,17 +728,26 @@ fn build_window(app: &adw::Application) {
         cancel_file_thumbnails(&ui_nav);
         sync_sidebar(&ui_nav);
         match st.visible_child_name().as_deref() {
-            Some("browser") => load_browser(&ui_nav),
+            Some("browser") => reload_browser_view(&ui_nav),
             // The Albums and Places listings are re-read in place. Loading the
             // timeline instead would swap it in under the Albums or Places toggle.
+            // The timeline, an album or a place comes back as it was left,
+            // scrolled where it was, unless photos changed while it was out of
+            // sight (see `follow_changes`) or nothing is loaded yet.
             Some("gallery") if !ui_nav.gallery.in_collection() => {
                 match ui_nav.gallery.view_switch.active() {
                     VIEW_ALBUMS => load_albums(&ui_nav),
                     VIEW_PLACES => load_places(&ui_nav),
-                    _ => load_gallery(&ui_nav, false),
+                    _ if ui_nav.gallery.timeline_stale.replace(false)
+                        || ui_nav.gallery.model.n_items() == 0 =>
+                    {
+                        load_gallery(&ui_nav, false)
+                    }
+                    _ => {}
                 }
             }
-            Some("gallery") => load_gallery(&ui_nav, false),
+            Some("gallery") if ui_nav.gallery.model.n_items() == 0 => load_gallery(&ui_nav, false),
+            Some("gallery") => {}
             // Every visit reads the page again. The rows already on screen stay
             // up while it does, so arriving costs no "Loading…" flash.
             Some("sharedbyme") => load_shared_by_me(&ui_nav),
@@ -711,13 +762,18 @@ fn build_window(app: &adw::Application) {
         }
     });
 
+    let saved = ui.dirs.load_config().window.usable();
     let window = adw::ApplicationWindow::builder()
         .application(app)
         .title("Proton Drive")
-        .default_width(980)
-        .default_height(680)
+        .default_width(saved.width)
+        .default_height(saved.height)
+        .maximized(saved.maximized)
+        .width_request(WindowState::MIN_WIDTH)
+        .height_request(WindowState::MIN_HEIGHT)
         .content(&toasts)
         .build();
+    remember_window_state(&ui, app, &window);
     // A wide window docks the details pane beside the files instead of laying it
     // over them.
     let wide = adw::Breakpoint::new(
@@ -725,6 +781,18 @@ fn build_window(app: &adw::Application) {
     );
     wide.add_setter(&ui.browser.split, "collapsed", Some(&false.to_value()));
     window.add_breakpoint(wide);
+    // A narrow window shows the sidebar and the page in turn, so every header
+    // bar keeps room for the window buttons. Signals rather than a setter:
+    // `refresh` decides the collapse while signed out, and would undo one.
+    let narrow = adw::Breakpoint::new(
+        adw::BreakpointCondition::parse("max-width: 760sp").expect("static breakpoint"),
+    );
+    narrow.add_setter(&ui.browser.search, "width-chars", Some(&8.to_value()));
+    let ui_narrow = ui.clone();
+    narrow.connect_apply(move |_| set_narrow(&ui_narrow, true));
+    let ui_wide = ui.clone();
+    narrow.connect_unapply(move |_| set_narrow(&ui_wide, false));
+    window.add_breakpoint(narrow);
     install_shortcuts(&ui, &window);
     install_window_actions(&ui, &window);
     install_launch_actions(&ui, app, &window);
@@ -738,6 +806,52 @@ fn build_window(app: &adw::Application) {
     window.present();
 }
 
+/// Follow the narrow breakpoint. While signed out the login page keeps the
+/// split collapsed whatever the width.
+fn set_narrow(ui: &Ui, narrow: bool) {
+    ui.narrow.set(narrow);
+    set_photos_narrow(ui, narrow);
+    if ui.session.borrow().is_some() {
+        ui.nav.set_collapsed(narrow);
+    }
+}
+
+/// Save the window's size when it closes, and when the app quits with the
+/// window still open (Ctrl+Q, the tray's Quit), which never asks it to close.
+fn remember_window_state(ui: &Rc<Ui>, app: &adw::Application, window: &adw::ApplicationWindow) {
+    let ui_close = ui.clone();
+    window.connect_close_request(move |window| {
+        save_window_state(&ui_close, window);
+        glib::Propagation::Proceed
+    });
+    let ui_quit = ui.clone();
+    let window_quit = window.downgrade();
+    app.connect_shutdown(move |_| {
+        if let Some(window) = window_quit.upgrade() {
+            save_window_state(&ui_quit, &window);
+        }
+    });
+}
+
+/// Write the window's unmaximised size and maximised state to the config, if
+/// either changed. Runs as the window goes away, so a failure is only logged.
+fn save_window_state(ui: &Ui, window: &adw::ApplicationWindow) {
+    let (width, height) = window.default_size();
+    let state = WindowState {
+        width,
+        height,
+        maximized: window.is_maximized(),
+    };
+    let mut config = ui.dirs.load_config();
+    if config.window == state {
+        return;
+    }
+    config.window = state;
+    if let Err(e) = ui.dirs.save_config(&config) {
+        tracing::warn!("cannot save the window size: {e}");
+    }
+}
+
 /// Whether `window` is minimised or otherwise out of sight (another workspace,
 /// fully covered), as far as the compositor tells us.
 fn window_hidden(window: &adw::ApplicationWindow) -> bool {
@@ -760,11 +874,7 @@ fn window_hidden(window: &adw::ApplicationWindow) -> bool {
 /// sync, set off by a separator.
 const DESTINATIONS: [(&str, &str, &str); 7] = [
     ("browser", gettext_noop("My files"), "folder-symbolic"),
-    (
-        "gallery",
-        gettext_noop("Photos"),
-        "image-x-generic-symbolic",
-    ),
+    ("gallery", gettext_noop("Photos"), "pdfs-photos-symbolic"),
     (
         "shared",
         gettext_noop("Shared with me"),
@@ -784,10 +894,13 @@ const DESTINATIONS: [(&str, &str, &str); 7] = [
 /// Index of the first row in the sidebar's sync section.
 const SIDEBAR_SYNC_SECTION: i32 = 6;
 
-/// The navigation sidebar: the destinations over a footer carrying the sync
-/// status, the account quota and the account menu. Returns the page (for the
+/// The navigation sidebar: the destinations under the update banner and over a
+/// footer carrying the sync status, the account quota and the account menu. Returns the page (for the
 /// split view) and the list (to drive + reflect the current page).
-fn build_sidebar(footer: &gtk4::Box) -> (adw::NavigationPage, gtk4::ListBox) {
+fn build_sidebar(
+    footer: &gtk4::Box,
+    update_banner: &adw::Banner,
+) -> (adw::NavigationPage, gtk4::ListBox) {
     let list = gtk4::ListBox::new();
     list.set_selection_mode(gtk4::SelectionMode::Single);
     list.add_css_class("navigation-sidebar");
@@ -840,6 +953,7 @@ fn build_sidebar(footer: &gtk4::Box) -> (adw::NavigationPage, gtk4::ListBox) {
         .build();
     let toolbar = adw::ToolbarView::new();
     toolbar.add_top_bar(&header);
+    toolbar.add_top_bar(update_banner);
     toolbar.set_content(Some(&scroll));
     toolbar.add_bottom_bar(footer);
 
@@ -865,6 +979,18 @@ fn set_busy_spinners(visible: bool) {
     });
 }
 
+/// `row` in a frame that scrolls sideways once the window is too narrow for it,
+/// so a row of labelled buttons never sets the window's minimum width.
+fn scroll_sideways(row: &impl IsA<gtk4::Widget>) -> gtk4::ScrolledWindow {
+    gtk4::ScrolledWindow::builder()
+        .hscrollbar_policy(gtk4::PolicyType::Automatic)
+        .vscrollbar_policy(gtk4::PolicyType::Never)
+        .propagate_natural_width(true)
+        .propagate_natural_height(true)
+        .child(row)
+        .build()
+}
+
 /// A destination page's frame: its own header bar over the page content, the
 /// way GNOME apps lay a split view out. The title sits in the middle with the
 /// busy spinner beside it; the page packs its actions into the returned header
@@ -928,6 +1054,14 @@ fn wire_sidebar(ui: &Rc<Ui>) {
             ui_row.stack.set_visible_child_name(page);
         }
     });
+    // In a narrow window the sidebar covers the page, so picking a row, even
+    // the selected one, has to bring the page forward.
+    let ui_open = ui.clone();
+    ui.sidebar.connect_row_activated(move |_, _| {
+        if ui_open.nav.is_collapsed() {
+            ui_open.nav.set_show_content(true);
+        }
+    });
 }
 
 /// Re-fetch the visible page from the server, bypassing every layer of cache
@@ -943,7 +1077,7 @@ fn reload_current_page(ui: &Rc<Ui>) {
     match ui.stack.visible_child_name().as_deref() {
         Some("browser") => {
             let path = ui.browser.path.borrow().clone();
-            refresh_then(ui, RefreshScope::Dir { path }, load_browser);
+            refresh_then(ui, RefreshScope::Dir { path }, reload_browser_view);
         }
         // One scope covers the whole photos view, so Refresh reloads whichever of
         // the views — a grid, or the timeline, an album or a place — is on screen.
@@ -1063,8 +1197,17 @@ pub(crate) fn set_sidebar_badge(ui: &Ui, page: &str, count: u64) {
 /// Show a transient toast. Non-blocking by design: an action's outcome is
 /// reported without stealing focus or forcing a click, so the user can keep
 /// working while a slow upload lands.
+///
+/// A toast's title is Pango markup unless told otherwise. Messages carry file
+/// names and daemon errors, and one with a `&` or `<` in it showed as an empty
+/// toast, so every toast here is plain text.
 fn toast(ui: &Rc<Ui>, message: &str) {
-    ui.toasts.add_toast(adw::Toast::new(message));
+    ui.toasts.add_toast(
+        adw::Toast::builder()
+            .title(message)
+            .use_markup(false)
+            .build(),
+    );
 }
 
 /// Show a toast that offers one follow-up action — an Undo, or a way to the page
@@ -1075,6 +1218,7 @@ fn toast(ui: &Rc<Ui>, message: &str) {
 fn toast_action(ui: &Rc<Ui>, message: &str, label: &str, action: impl Fn(&Rc<Ui>) + 'static) {
     let toast = adw::Toast::builder()
         .title(message)
+        .use_markup(false)
         .button_label(label)
         .timeout(8)
         .build();
@@ -1097,7 +1241,11 @@ fn toast_error(ui: &Rc<Ui>, what: &str, detail: &str) {
         gettext_f("{what}: {detail}", &[("what", what), ("detail", detail)])
     };
     tracing::warn!("{message}");
-    let toast = adw::Toast::builder().title(&message).timeout(6).build();
+    let toast = adw::Toast::builder()
+        .title(&message)
+        .use_markup(false)
+        .timeout(6)
+        .build();
     ui.toasts.add_toast(toast);
 }
 
@@ -1191,7 +1339,7 @@ fn install_window_actions(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
     // The Albums view's New Album button.
     let new_album = gio::SimpleAction::new("new-album", None);
     let ui_album = ui.clone();
-    new_album.connect_activate(move |_, _| prompt_new_album(&ui_album, Vec::new()));
+    new_album.connect_activate(move |_, _| prompt_new_album(&ui_album, Vec::new(), None));
     window.add_action(&new_album);
 
     let shortcuts = gio::SimpleAction::new("shortcuts", None);
@@ -1387,6 +1535,9 @@ fn show_shortcuts(window: &adw::ApplicationWindow) {
                 ("<Alt>Left <Alt>Right", gettext_noop("Back / forward")),
                 ("<Alt>Up", gettext_noop("Parent folder")),
                 ("<Control>1 <Control>2", gettext_noop("Grid / list")),
+                ("<Control>plus", gettext_noop("Larger thumbnails")),
+                ("<Control>minus", gettext_noop("Smaller thumbnails")),
+                ("<Control>0", gettext_noop("Reset thumbnail size")),
                 ("F2", gettext_noop("Rename")),
                 ("Delete", gettext_noop("Move to Trash")),
                 ("Escape", gettext_noop("Clear the selection")),
@@ -1399,6 +1550,7 @@ fn show_shortcuts(window: &adw::ApplicationWindow) {
                 ("<Control>minus", gettext_noop("Smaller thumbnails")),
                 ("<Control>0", gettext_noop("Reset thumbnail size")),
                 ("<Control>a", gettext_noop("Select all")),
+                ("Escape <Alt>Left", gettext_noop("Back")),
             ],
         ),
         (
@@ -1408,8 +1560,11 @@ fn show_shortcuts(window: &adw::ApplicationWindow) {
                 ("Home End", gettext_noop("First / last photo")),
                 ("i", gettext_noop("Show details")),
                 ("f", gettext_noop("Fullscreen")),
+                ("F5", gettext_noop("Slideshow")),
+                ("F10", gettext_noop("More")),
+                ("<Control>c", gettext_noop("Copy Image")),
                 ("Delete", gettext_noop("Move to Trash")),
-                ("Escape", gettext_noop("Close")),
+                ("Escape <Alt>Left", gettext_noop("Close")),
             ],
         ),
     ];
@@ -1435,8 +1590,17 @@ fn install_shortcuts(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
     controller.connect_key_pressed(move |_, key, _, state| {
         let ctrl = state.contains(gtk4::gdk::ModifierType::CONTROL_MASK);
         let alt = state.contains(gtk4::gdk::ModifierType::ALT_MASK);
-        let on_browser = ui.stack.visible_child_name().as_deref() == Some("browser");
-        let on_trash = ui.stack.visible_child_name().as_deref() == Some("trash");
+        let page = ui.stack.visible_child_name();
+        let on_browser = page.as_deref() == Some("browser");
+        let on_trash = page.as_deref() == Some("trash");
+        let on_gallery = page.as_deref() == Some("gallery");
+        // Pages with a level to go back to, besides My files' own history.
+        let in_collection = on_gallery && ui.gallery.in_collection();
+        let in_shared_folder =
+            page.as_deref() == Some("shared") && !ui.shared.nav.borrow().is_empty();
+        let in_device_folder =
+            page.as_deref() == Some("devices") && !ui.devices.nav.borrow().is_empty();
+        let back_key = (key == gtk4::gdk::Key::Left && alt) || key == gtk4::gdk::Key::BackSpace;
         match key {
             // Refresh works on every page, so it is matched before the
             // browser-only bindings.
@@ -1452,6 +1616,21 @@ fn install_shortcuts(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
                 ui.browser.search.grab_focus();
             }
             gtk4::gdk::Key::n | gtk4::gdk::Key::N if ctrl && on_browser => prompt_new_folder(&ui),
+            gtk4::gdk::Key::plus | gtk4::gdk::Key::equal | gtk4::gdk::Key::KP_Add
+                if ctrl && on_browser && !ui.browser.files.shows_list() =>
+            {
+                zoom_files(&ui, 1)
+            }
+            gtk4::gdk::Key::minus | gtk4::gdk::Key::KP_Subtract
+                if ctrl && on_browser && !ui.browser.files.shows_list() =>
+            {
+                zoom_files(&ui, -1)
+            }
+            gtk4::gdk::Key::_0 | gtk4::gdk::Key::KP_0
+                if ctrl && on_browser && !ui.browser.files.shows_list() =>
+            {
+                zoom_files(&ui, 0)
+            }
             gtk4::gdk::Key::_1 | gtk4::gdk::Key::_2 if ctrl && on_browser => set_files_view(
                 &ui,
                 FilesView {
@@ -1478,6 +1657,21 @@ fn install_shortcuts(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
             gtk4::gdk::Key::BackSpace if on_browser => {
                 ui.browser.actions.activate_action("back", None)
             }
+            // Selection mode ends before Escape leaves anything; the grid
+            // handles this itself while it has the focus.
+            gtk4::gdk::Key::Escape if on_gallery && ui.gallery.selecting.get() => {
+                set_selection_mode(&ui, false)
+            }
+            // An album or a place is a level below Photos, as a folder is
+            // below its parent: Back leaves it, and so does Escape.
+            _ if in_collection
+                && !ui.gallery.selecting.get()
+                && (back_key || key == gtk4::gdk::Key::Escape) =>
+            {
+                ui.gallery.back.emit_clicked()
+            }
+            _ if in_shared_folder && back_key => shared_back(&ui),
+            _ if in_device_folder && back_key => devices_back(&ui),
             gtk4::gdk::Key::u | gtk4::gdk::Key::U if ctrl && on_browser => prompt_upload(&ui),
             gtk4::gdk::Key::Menu if visible_file_list(&ui).is_some() => {
                 if let Some(list) = visible_file_list(&ui) {
@@ -1665,13 +1859,52 @@ pub(crate) fn service_unreachable(
             );
             return;
         }
-        status(
-            &ui,
-            "network-idle-symbolic",
-            &gettext("Connecting…"),
-            &gettext("Waiting for the Proton Drive service to start."),
-            false,
-        );
+        // Running but not answering may be a mount that fails on every try,
+        // which never opens the socket. Its reason is in a file the daemon
+        // keeps for this (B263); "Connecting…" alone looked like a slow start
+        // for as long as it lasted.
+        let state_dir = ui.dirs.state_dir();
+        let failure = gio::spawn_blocking(move || pdfs_core::mountfail::read(&state_dir))
+            .await
+            .ok()
+            .flatten();
+        match failure {
+            Some(failure) if failure.not_empty.is_some() => {
+                let found = failure.not_empty.as_ref().expect("checked above");
+                status(
+                    &ui,
+                    "dialog-warning-symbolic",
+                    &gettext("Can't open your Drive"),
+                    // Translators: {path} is the folder My files is mounted at.
+                    &gettext_f(
+                        "“{path}” already has files in it, and My files would hide them. Proton Drive tries again on its own once the folder is empty. You can also choose another folder for My files in Preferences.",
+                        &[("path", &found.path.display().to_string())],
+                    ),
+                    true,
+                );
+                if ui.not_empty_offered.replace(failure.since) != failure.since {
+                    offer_not_empty(&ui, found);
+                }
+            }
+            Some(failure) => status(
+                &ui,
+                "dialog-warning-symbolic",
+                &gettext("Can't open your Drive"),
+                // Translators: {error} is an error message, in English.
+                &gettext_f(
+                    "The Proton Drive service keeps failing to start and tries again on its own. The last error was: {error}",
+                    &[("error", &failure.error)],
+                ),
+                true,
+            ),
+            None => status(
+                &ui,
+                "network-idle-symbolic",
+                &gettext("Connecting…"),
+                &gettext("Waiting for the Proton Drive service to start."),
+                false,
+            ),
+        }
         glib::timeout_add_local_once(CONNECT_RETRY_INTERVAL, move || {
             if ui.stack.visible_child_name().as_deref() == Some(page) {
                 reload(&ui);
@@ -1680,6 +1913,37 @@ pub(crate) fn service_unreachable(
     });
 }
 
+/// Tell the user the daemon will not mount My files over a folder with files
+/// in it (B277), and offer the two ways out: open the folder to move them, or
+/// choose another one.
+fn offer_not_empty(ui: &Rc<Ui>, found: &pdfs_core::mountpoint::NotEmpty) {
+    let path = found.path.display().to_string();
+    let dialog = adw::AlertDialog::builder()
+        .heading(gettext("Your Proton Drive Folder Isn't Empty"))
+        // Translators: {path} is the folder My files is mounted at; {n} is how
+        // many files and folders are already in it.
+        .body(ngettext_f(
+            "“{path}” already has {n} item in it. My files would hide it, so Proton Drive does not open there. Move the item to another folder, or choose another folder for My files.",
+            "“{path}” already has {n} items in it. My files would hide them, so Proton Drive does not open there. Move the items to another folder, or choose another folder for My files.",
+            found.count as u64,
+            &[("path", &path)],
+        ))
+        .build();
+    dialog.add_response("close", &gettext("Not Now"));
+    dialog.add_response("open", &gettext("Open Folder"));
+    dialog.add_response("choose", &gettext("Choose Another Folder…"));
+    dialog.set_response_appearance("choose", adw::ResponseAppearance::Suggested);
+    dialog.set_default_response(Some("choose"));
+    dialog.set_close_response("close");
+    let ui_response = ui.clone();
+    dialog.connect_response(None, move |_, response| match response {
+        "open" => open_path(&path),
+        "choose" => prompt_mountpoint(&ui_response),
+        _ => {}
+    });
+    dialog.present(ui_window(ui).as_ref());
+}
+
 /// How long a copy button shows its check after copying.
 const COPIED_FEEDBACK: Duration = Duration::from_millis(1500);
 
@@ -1697,9 +1961,12 @@ pub(crate) fn flash_copied(button: &gtk4::Button, icon: &'static str) {
 
 /// Open a local path with the handler the user configured — `xdg-open` unless
 /// `open_with` in `config.json` overrides it for this kind of file.
+///
+/// On a thread of its own: telling a folder from a file is a `stat`, and the
+/// path is often in the mount, which may hang.
 fn open_path(path: &str) {
-    let path = Path::new(path);
-    pdfs_core::opener::open_default(path, path.is_dir());
+    let path = PathBuf::from(path);
+    std::thread::spawn(move || pdfs_core::opener::open_default(&path, path.is_dir()));
 }
 
 /// [`open_path`] for a file the daemon materialised into the content cache,
@@ -1746,6 +2013,7 @@ mod tests {
             favorite: false,
             group_size: 2,
             has_raw: kind == PhotoKind::Raw,
+            place_id: None,
         }
     }
 
@@ -1768,6 +2036,33 @@ mod tests {
         assert!(next_group_member(&[], "jpeg").is_none());
     }
 
+    /// The pill names what kind of shot it switches through, and lights up
+    /// on the file that is not the shot's main one.
+    #[test]
+    fn the_group_pill_names_the_kind_of_shot() {
+        let pair = [
+            member("jpeg", Some("IMG_1.JPG"), PhotoKind::Photo),
+            member("raw", Some("IMG_1.CR2"), PhotoKind::Raw),
+        ];
+        assert_eq!(group_pill(&pair, "jpeg"), Some(("RAW".into(), false)));
+        assert_eq!(group_pill(&pair, "raw"), Some(("RAW".into(), true)));
+
+        let live = [
+            member("still", Some("IMG_2.HEIC"), PhotoKind::Photo),
+            member("clip", Some("IMG_2.MOV"), PhotoKind::Video),
+        ];
+        assert_eq!(group_pill(&live, "still"), Some(("Live".into(), false)));
+        assert_eq!(group_pill(&live, "clip"), Some(("Live".into(), true)));
+
+        let burst = [
+            member("a", None, PhotoKind::Photo),
+            member("b", None, PhotoKind::Photo),
+            member("c", None, PhotoKind::Photo),
+        ];
+        assert_eq!(group_pill(&burst, "b"), Some(("2 of 3".into(), false)));
+        assert_eq!(group_pill(&burst, "elsewhere"), None);
+    }
+
     /// The switch names what it will show; a file whose name the daemon has not
     /// resolved still gets a sentence rather than a blank.
     #[test]

crates/pdfs-gui/src/app/pages/activity.rs

@@ -378,7 +378,9 @@ pub(crate) fn activity_status(
 ) {
     ui.activity.status.set_icon_name(Some(icon));
     ui.activity.status.set_title(title);
-    ui.activity.status.set_description(Some(description));
+    ui.activity
+        .status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.activity.retry.set_visible(retry);
     ui.activity.content.set_visible_child_name("status");
 }
@@ -1041,6 +1043,7 @@ pub(crate) fn activity_icon(kind: ActivityKind) -> &'static str {
         ActivityKind::Sync => "pdfs-sync-symbolic",
         ActivityKind::Rename => "document-edit-symbolic",
         ActivityKind::Move => "go-jump-symbolic",
+        ActivityKind::Copy => "edit-copy-symbolic",
         ActivityKind::CreateFolder => "folder-new-symbolic",
         ActivityKind::Trash => "user-trash-symbolic",
         ActivityKind::DeleteForever | ActivityKind::EmptyTrash => "edit-delete-symbolic",

crates/pdfs-gui/src/app/pages/activity_text.rs

@@ -179,6 +179,10 @@ pub(crate) fn activity_title(kind: ActivityKind, ok: bool, name: &str) -> String
         (ActivityKind::Move, true) => gettext_f("Moved {name}", &args),
         // Translators: {name} is a file or folder name.
         (ActivityKind::Move, false) => gettext_f("Couldn't move {name}", &args),
+        // Translators: {name} is a file or folder name.
+        (ActivityKind::Copy, true) => gettext_f("Copied {name}", &args),
+        // Translators: {name} is a file or folder name.
+        (ActivityKind::Copy, false) => gettext_f("Couldn't copy {name}", &args),
         // Translators: {name} is a folder name.
         (ActivityKind::CreateFolder, true) => gettext_f("Created folder {name}", &args),
         // Translators: {name} is a folder name.

crates/pdfs-gui/src/app/pages/albums.rs

@@ -40,7 +40,7 @@ pub(crate) fn load_albums(ui: &Rc<Ui>) {
     if ui.gallery.albums_stack.visible_child_name().as_deref() != Some("grid") {
         albums_status(
             ui,
-            "view-grid-symbolic",
+            "pdfs-album-symbolic",
             &gettext("Loading albums…"),
             &gettext("Reading your Proton Drive albums."),
         );
@@ -62,7 +62,7 @@ pub(crate) fn load_albums(ui: &Rc<Ui>) {
             ),
             Ok(Ok(Response::Albums { items, .. })) if items.is_empty() => albums_status(
                 &ui,
-                "view-grid-symbolic",
+                "pdfs-album-symbolic",
                 &gettext("No albums"),
                 &gettext("Create one with New Album, or in Proton Photos."),
             ),
@@ -136,7 +136,7 @@ fn album_card(ui: &Rc<Ui>, album: &AlbumInfo) -> gtk4::Button {
     picture.add_css_class("photo-thumb");
 
     let placeholder = gtk4::Image::builder()
-        .icon_name("view-grid-symbolic")
+        .icon_name("pdfs-album-symbolic")
         .pixel_size(32)
         .halign(gtk4::Align::Center)
         .valign(gtk4::Align::Center)
@@ -225,12 +225,13 @@ fn show_album_menu(ui: &Rc<Ui>, album: &AlbumInfo, anchor: &gtk4::Widget, x: f64
 /// while the entry is blank.
 fn prompt_album_name(
     ui: &Rc<Ui>,
+    parent: Option<gtk4::Window>,
     heading: &str,
     action: &str,
     current: &str,
     on_name: impl Fn(String) + 'static,
 ) {
-    let win = ui_window(ui);
+    let win = parent.or_else(|| ui_window(ui));
     let dialog = adw::AlertDialog::builder().heading(heading).build();
     let group = adw::PreferencesGroup::new();
     let row = adw::EntryRow::builder()
@@ -260,10 +261,12 @@ fn prompt_album_name(
 }
 
 /// Ask for a name and create an album, then add `photos` to it, if any.
-pub(crate) fn prompt_new_album(ui: &Rc<Ui>, photos: Vec<String>) {
+///
+/// The dialogs open over `parent`, or over the main window without one.
+pub(crate) fn prompt_new_album(ui: &Rc<Ui>, photos: Vec<String>, parent: Option<gtk4::Window>) {
     let ui_c = ui.clone();
     let (heading, action) = (gettext("New Album"), gettext("Create"));
-    prompt_album_name(ui, &heading, &action, "", move |name| {
+    prompt_album_name(ui, parent, &heading, &action, "", move |name| {
         let rx = spawn_request(ui_c.dirs.control_socket(), Request::CreateAlbum { name });
         let ui = ui_c.clone();
         let photos = photos.clone();
@@ -296,7 +299,7 @@ pub(crate) fn prompt_new_album(ui: &Rc<Ui>, photos: Vec<String>) {
 fn prompt_rename_album(ui: &Rc<Ui>, album: &AlbumInfo) {
     let (ui_c, uid) = (ui.clone(), album.uid.clone());
     let (heading, action) = (gettext("Rename Album"), gettext("Rename"));
-    prompt_album_name(ui, &heading, &action, &album.name, move |name| {
+    prompt_album_name(ui, None, &heading, &action, &album.name, move |name| {
         run_album_request(
             &ui_c,
             Request::RenameAlbum {
@@ -368,7 +371,7 @@ fn reload_album_grid(ui: &Rc<Ui>) {
 }
 
 /// Offer our own albums to add `photos` to, plus a new one.
-pub(crate) fn prompt_add_to_album(ui: &Rc<Ui>, photos: Vec<String>) {
+pub(crate) fn prompt_add_to_album(ui: &Rc<Ui>, photos: Vec<String>, parent: Option<gtk4::Window>) {
     let rx = spawn_request(ui.dirs.control_socket(), Request::PhotoAlbums);
     let ui = ui.clone();
     glib::spawn_future_local(async move {
@@ -390,7 +393,7 @@ pub(crate) fn prompt_add_to_album(ui: &Rc<Ui>, photos: Vec<String>) {
             }
         };
         if albums.is_empty() {
-            prompt_new_album(&ui, photos);
+            prompt_new_album(&ui, photos, parent);
             return;
         }
 
@@ -436,11 +439,11 @@ pub(crate) fn prompt_add_to_album(ui: &Rc<Ui>, photos: Vec<String>) {
                 add_to_album(&ui_c, album.uid.clone(), photos_c.clone());
             }
         });
-        let ui_c = ui.clone();
+        let (ui_c, parent_c) = (ui.clone(), parent.clone());
         dialog.connect_response(Some("new"), move |_, _| {
-            prompt_new_album(&ui_c, photos.clone())
+            prompt_new_album(&ui_c, photos.clone(), parent_c.clone())
         });
-        dialog.present(ui_window(&ui).as_ref());
+        dialog.present(parent.or_else(|| ui_window(&ui)).as_ref());
     });
 }
 
@@ -595,10 +598,7 @@ pub(crate) fn want_cover(ui: &Rc<Ui>, uid: String, picture: &gtk4::Picture) {
     if ui.gallery.photo_nothumb.borrow().contains(&uid) {
         return;
     }
-    ui.gallery
-        .thumb_wanted
-        .borrow_mut()
-        .insert(uid.clone(), picture.clone());
+    ui.gallery.await_thumb(&uid, picture);
     let mut queue = ui.gallery.thumb_queue.borrow_mut();
     if !queue.contains(&uid) {
         queue.push_back(uid);
@@ -618,9 +618,7 @@ pub(crate) fn open_album(ui: &Rc<Ui>, album: AlbumInfo) {
     // would silently do something else. The Photos/Albums switcher goes too: an
     // album is a level below it, and back is the way out.
     ui.gallery.filters.set_visible(false);
-    ui.gallery.view_switch.widget().set_visible(false);
-    ui.gallery.upload.set_visible(false);
-    ui.gallery.back.set_visible(true);
+    sync_header(ui);
     // A stale kind/date filter would otherwise be sent with the album request.
     ui.gallery.kind.set(None);
     ui.gallery.range.set(None);
@@ -636,16 +634,16 @@ pub(crate) fn close_album(ui: &Rc<Ui>) {
         return;
     }
     ui.gallery.title.set_title(&gettext("Photos"));
-    ui.gallery.view_switch.widget().set_visible(true);
-    ui.gallery.upload.set_visible(true);
-    ui.gallery.back.set_visible(false);
+    sync_header(ui);
 }
 
 /// Show the album grid's own status page (loading, empty, or an error).
 fn albums_status(ui: &Rc<Ui>, icon: &str, title: &str, description: &str) {
     ui.gallery.albums_status.set_icon_name(Some(icon));
     ui.gallery.albums_status.set_title(title);
-    ui.gallery.albums_status.set_description(Some(description));
+    ui.gallery
+        .albums_status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.gallery.albums_stack.set_visible_child_name("status");
 }
 
@@ -666,12 +664,25 @@ pub(crate) fn wire_albums(ui: &Rc<Ui>) {
         }
         close_album(&ui_photos);
         close_place(&ui_photos);
-        ui_photos.gallery.filters.set_visible(true);
-        ui_photos.gallery.content.set_visible_child_name("timeline");
+        let gallery = &ui_photos.gallery;
+        gallery.filters.set_visible(true);
+        gallery.content.set_visible_child_name("timeline");
+        // An album or a place cleared the kind and the month it does not use;
+        // the filter controls still show them, so the timeline comes back
+        // filtered the way they say.
+        let kind = kind_for_tab(gallery.tabs.active() as usize);
+        let range = gallery
+            .date_ranges
+            .borrow()
+            .get(gallery.dates.selected() as usize)
+            .copied()
+            .flatten();
+        let kind_changed = gallery.kind.replace(kind) != kind;
+        let range_changed = gallery.range.replace(range) != range;
+        let refiltered = kind_changed || range_changed;
         // The timeline comes back as it was left unless an album took over the
         // model since; then it has to be reloaded.
-        if ui_photos.gallery.timeline_stale.replace(false) || ui_photos.gallery.model.n_items() == 0
-        {
+        if gallery.timeline_stale.replace(false) || refiltered || gallery.model.n_items() == 0 {
             load_gallery(&ui_photos, false);
         } else {
             update_gallery_subtitle(&ui_photos);

crates/pdfs-gui/src/app/pages/browser.rs

@@ -1,6 +1,14 @@
-use crate::activation::{DriveActivation, drive_activation, mounted_path, mounted_target_rel};
+use crate::activation::{DriveActivation, drive_activation, mounted_path, present_within};
 use crate::*;
 
+/// How a folder in My files was left: scrolled `offset` px down, with the
+/// entries named `selected` highlighted.
+#[derive(Clone, Debug, Default, PartialEq)]
+pub(crate) struct FolderPlace {
+    pub(crate) offset: f64,
+    pub(crate) selected: Vec<String>,
+}
+
 pub(crate) struct BrowserState {
     // Files (browser) page.
     /// The grid and list; the model is repopulated per directory.
@@ -10,6 +18,13 @@ pub(crate) struct BrowserState {
     /// breadcrumb.
     pub(crate) history: RefCell<Vec<String>>,
     pub(crate) future: RefCell<Vec<String>>,
+    /// Where each folder left by Back, Forward, Up or a descent was scrolled
+    /// and what was selected in it, by path. Back, Forward and Up put the
+    /// folder back that way; opening it afresh starts at the top.
+    pub(crate) places: RefCell<HashMap<String, FolderPlace>>,
+    /// The folder whose [`Self::places`] entry the next listing restores, set
+    /// by Back, Forward and Up.
+    pub(crate) restore: RefCell<Option<String>>,
     /// Clickable breadcrumb trail (a button per path segment); rebuilt per load
     /// by [`repaint_crumb`] so each ancestor folder navigates on click.
     pub(crate) crumb: gtk4::Box,
@@ -77,6 +92,8 @@ pub(crate) struct BrowserState {
     /// zoom value, and Proton account storage usage.
     pub(crate) summary: gtk4::Label,
     pub(crate) zoom: gtk4::Scale,
+    /// Saves the zoom once the slider rests, not on every step.
+    pub(crate) zoom_save: RefCell<Option<glib::SourceId>>,
 }
 
 /// Idle pause after the last keystroke before a search query is sent, so typing
@@ -87,9 +104,11 @@ pub(crate) const SEARCH_DEBOUNCE: Duration = Duration::from_millis(250);
 pub(crate) const SEARCH_LIMIT: usize = 200;
 
 /// Browser grid thumbnail size controlled by the bottom zoom slider. The
-/// default preserves the former fixed 72 px presentation.
+/// default preserves the former fixed 72 px presentation. The largest size is
+/// big enough to tell photos apart by their thumbnail, and thumbnails are
+/// 512 px, so they stay sharp up to it on a 2× screen.
 pub(crate) const GRID_THUMB_MIN: i32 = 48;
-pub(crate) const GRID_THUMB_MAX: i32 = 144;
+pub(crate) const GRID_THUMB_MAX: i32 = 256;
 pub(crate) const GRID_THUMB_DEFAULT: i32 = 72;
 pub(crate) const GRID_THUMB_STEP: i32 = 8;
 
@@ -376,7 +395,7 @@ pub(crate) fn build_browser_page() -> (gtk4::Widget, BrowserWidgets) {
     bulk_box.append(&bulk_clear);
     let bulk = gtk4::Revealer::builder()
         .transition_type(gtk4::RevealerTransitionType::SlideDown)
-        .child(&bulk_box)
+        .child(&scroll_sideways(&bulk_box))
         .build();
 
     // The status bar: contextual text (stretch 1), then the icon-size slider.
@@ -500,7 +519,9 @@ pub(crate) fn build_browser_page() -> (gtk4::Widget, BrowserWidgets) {
 pub(crate) fn browser_status(ui: &Rc<Ui>, icon: &str, title: &str, description: &str, retry: bool) {
     ui.browser.status.set_icon_name(Some(icon));
     ui.browser.status.set_title(title);
-    ui.browser.status.set_description(Some(description));
+    ui.browser
+        .status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.browser.retry.set_visible(retry);
     // Only the empty-folder state offers a way to fill the folder; every other
     // status (loading, offline, error) turns them back off.
@@ -520,9 +541,9 @@ pub(crate) fn clear_selection(ui: &Rc<Ui>) {
 }
 
 /// Reflect the current selection in the bulk bar: how many are selected, and
-/// which bulk actions apply to that mix. Offline state is a file-only notion, so
-/// a folder anywhere in the selection disables the two pin buttons rather than
-/// half-failing once pressed.
+/// which bulk actions apply to that mix. An entry kept offline through a pinned
+/// folder above it cannot be made online only on its own, so it does not count
+/// towards Make online only.
 pub(crate) fn sync_bulk_bar(ui: &Rc<Ui>) {
     let entries = selected_entries(ui);
     // One selected entry is the details pane's job; the bar is for a batch.
@@ -530,8 +551,7 @@ pub(crate) fn sync_bulk_bar(ui: &Rc<Ui>) {
         ui.browser.bulk.set_reveal_child(false);
         return;
     }
-    let files_only = entries.iter().all(|e| !e.is_dir);
-    let any_pinned = entries.iter().any(|e| e.pinned);
+    let any_pinned = entries.iter().any(|e| e.pinned && !e.pinned_by_folder);
     let any_unpinned = entries.iter().any(|e| !e.pinned);
     let mounted = *ui.mounted.borrow();
     ui.browser.bulk_label.set_label(&ngettext_f(
@@ -541,12 +561,8 @@ pub(crate) fn sync_bulk_bar(ui: &Rc<Ui>) {
         &[],
     ));
     ui.browser.bulk_trash.set_sensitive(mounted);
-    ui.browser
-        .bulk_pin
-        .set_sensitive(mounted && files_only && any_unpinned);
-    ui.browser
-        .bulk_unpin
-        .set_sensitive(mounted && files_only && any_pinned);
+    ui.browser.bulk_pin.set_sensitive(mounted && any_unpinned);
+    ui.browser.bulk_unpin.set_sensitive(mounted && any_pinned);
     ui.browser.bulk.set_reveal_child(true);
 }
 
@@ -652,16 +668,19 @@ pub(crate) fn restore_uids(ui: &Rc<Ui>, uids: Vec<String>, count: usize) {
     );
 }
 
-/// Pin or unpin every selected file, one request at a time.
+/// Pin or unpin every selected entry, one request at a time. A folder's files
+/// download in the background, so its request returns before they are there.
 pub(crate) fn run_bulk_pin(ui: &Rc<Ui>, entries: Vec<DirEntry>, pin: bool) {
     let socket = ui.dirs.control_socket();
     // Only the entries that need changing: re-pinning an already-pinned file is
-    // a wasted round-trip, and it would inflate the count the toast reports.
-    let paths: Vec<String> = entries
+    // a wasted round-trip, and it would inflate the count the toast reports. One
+    // kept through a pinned folder above it has no pin of its own to remove.
+    let changing: Vec<&DirEntry> = entries
         .iter()
-        .filter(|e| !e.is_dir && e.pinned != pin)
-        .map(|e| entry_rel(ui, e))
+        .filter(|e| !e.pinned_by_folder && e.pinned != pin)
         .collect();
+    let any_folder = changing.iter().any(|e| e.is_dir);
+    let paths: Vec<String> = changing.iter().map(|e| entry_rel(ui, e)).collect();
     if paths.is_empty() {
         return;
     }
@@ -698,13 +717,27 @@ pub(crate) fn run_bulk_pin(ui: &Rc<Ui>, entries: Vec<DirEntry>, pin: bool) {
             (0, None) => {}
             (n, _) => toast(
                 &ui,
-                &if pin {
+                &if pin && any_folder {
+                    ngettext_f(
+                        "Making {n} item available offline…",
+                        "Making {n} items available offline…",
+                        n as u64,
+                        &[],
+                    )
+                } else if pin {
                     ngettext_f(
                         "{n} file is now available offline",
                         "{n} files are now available offline",
                         n as u64,
                         &[],
                     )
+                } else if any_folder {
+                    ngettext_f(
+                        "{n} item is now online only",
+                        "{n} items are now online only",
+                        n as u64,
+                        &[],
+                    )
                 } else {
                     ngettext_f(
                         "{n} file is now online only",
@@ -787,7 +820,35 @@ pub(crate) fn wire_browser(ui: &Rc<Ui>) {
             &[],
         )));
         ui_zoom.browser.files.set_thumbnail_size(size);
+        save_icon_size(&ui_zoom, size);
     });
+    // Ctrl+scroll steps the icon size, as in Photos. Capture phase so the
+    // scrolled window does not scroll the grid as well. A touchpad sends many
+    // small deltas, so they add up to a whole notch before each step.
+    if let Some(grid_scroll) = files.views.child_by_name("grid") {
+        let wheel = gtk4::EventControllerScroll::new(gtk4::EventControllerScrollFlags::VERTICAL);
+        wheel.set_propagation_phase(gtk4::PropagationPhase::Capture);
+        let ui_wheel = ui.clone();
+        let pending = Cell::new(0.0_f64);
+        wheel.connect_scroll(move |controller, _dx, dy| {
+            if !controller
+                .current_event_state()
+                .contains(gtk4::gdk::ModifierType::CONTROL_MASK)
+            {
+                pending.set(0.0);
+                return glib::Propagation::Proceed;
+            }
+            let total = pending.get() + dy;
+            let steps = total.trunc();
+            pending.set(total - steps);
+            if steps != 0.0 {
+                // Scrolling up (negative dy) makes the icons bigger.
+                zoom_files(&ui_wheel, -(steps as i32));
+            }
+            glib::Propagation::Stop
+        });
+        grid_scroll.add_controller(wheel);
+    }
 
     files
         .column_view
@@ -860,13 +921,17 @@ pub(crate) fn entry_context_menu(ui: &Rc<Ui>, entry: &DirEntry) -> ActionMenu {
     }
     menu.section();
 
-    if !entry.is_dir {
+    // Kept through a pinned folder above it, the entry has no pin of its own
+    // to remove: the check shows that state without offering to change it.
+    if entry.pinned_by_folder {
+        menu.locked_toggle(&gettext("Available offline"), true);
+    } else {
         let (ui_c, entry_c) = (ui.clone(), entry.clone());
         menu.toggle(&gettext("Available offline"), entry.pinned, move |_| {
             toggle_pin(&ui_c, &entry_c)
         });
-        menu.section();
     }
+    menu.section();
 
     let (ui_c, entry_c) = (ui.clone(), entry.clone());
     menu.item(&gettext("Share…"), move || {
@@ -886,6 +951,12 @@ pub(crate) fn entry_context_menu(ui: &Rc<Ui>, entry: &DirEntry) -> ActionMenu {
     menu.item(&gettext("Move To…"), move || {
         prompt_move(&ui_c, vec![entry_c.clone()])
     });
+    let (ui_c, entry_c) = (ui.clone(), entry.clone());
+    menu.item(&gettext("Make a Copy"), move || make_copy(&ui_c, &entry_c));
+    let (ui_c, entry_c) = (ui.clone(), entry.clone());
+    menu.item(&gettext("Copy To…"), move || {
+        prompt_copy(&ui_c, vec![entry_c.clone()])
+    });
     if !entry.is_dir {
         let (ui_c, entry_c) = (ui.clone(), entry.clone());
         menu.item(&gettext("Versions…"), move || {
@@ -908,9 +979,8 @@ pub(crate) fn entry_context_menu(ui: &Rc<Ui>, entry: &DirEntry) -> ActionMenu {
 /// simply absent here rather than offered and then refused.
 pub(crate) fn bulk_context_menu(ui: &Rc<Ui>, entries: Vec<DirEntry>) -> ActionMenu {
     let mut menu = ActionMenu::new();
-    // Offline state is a file-only notion; the check shows whether the whole
-    // batch already is.
-    if entries.iter().all(|e| !e.is_dir) {
+    // The check shows whether the whole batch already is offline.
+    {
         let (ui_c, batch) = (ui.clone(), entries.clone());
         let all_pinned = entries.iter().all(|e| e.pinned);
         menu.toggle(&gettext("Available offline"), all_pinned, move |pin| {
@@ -921,6 +991,10 @@ pub(crate) fn bulk_context_menu(ui: &Rc<Ui>, entries: Vec<DirEntry>) -> ActionMe
     menu.item(&gettext("Move To…"), move || {
         prompt_move(&ui_c, batch.clone())
     });
+    let (ui_c, batch) = (ui.clone(), entries.clone());
+    menu.item(&gettext("Copy To…"), move || {
+        prompt_copy(&ui_c, batch.clone())
+    });
     menu.labelled_section(&ngettext_f(
         "{n} selected",
         "{n} selected",
@@ -966,28 +1040,27 @@ pub(crate) fn background_context_menu(ui: &Rc<Ui>) -> ActionMenu {
 pub(crate) fn open_entry_with(ui: &Rc<Ui>, entry: &DirEntry) {
     let rel = entry_rel(ui, entry);
     let mountpoint = ui.dirs.resolved_mountpoint(&ui.dirs.load_config());
-    let Some(path) = mounted_target_rel(&mountpoint, &rel) else {
-        toast_error(
-            ui,
-            &gettext("Couldn't open file"),
-            &gettext("Open With needs the Proton Drive service to be running."),
-        );
-        return;
-    };
-    let launcher = gtk4::FileLauncher::new(Some(&gio::File::for_path(path)));
-    launcher.set_always_ask(true);
     let ui = ui.clone();
-    launcher.launch(
-        ui_window(&ui).as_ref(),
-        gio::Cancellable::NONE,
-        move |result| {
+    glib::spawn_future_local(async move {
+        let Some(path) = present_within(mounted_path(&mountpoint, &rel)).await else {
+            toast_error(
+                &ui,
+                &gettext("Couldn't open file"),
+                &gettext("Open With needs the Proton Drive service to be running."),
+            );
+            return;
+        };
+        let launcher = gtk4::FileLauncher::new(Some(&gio::File::for_path(path)));
+        launcher.set_always_ask(true);
+        let window = ui_window(&ui);
+        launcher.launch(window.as_ref(), gio::Cancellable::NONE, move |result| {
             if let Err(e) = result
                 && !e.matches(gtk4::DialogError::Dismissed)
             {
                 toast_error(&ui, &gettext("Couldn't open file"), &e.to_string());
             }
-        },
-    );
+        });
+    });
 }
 
 /// Copy the entry's public link, when it has one this client can read the
@@ -1095,27 +1168,29 @@ pub(crate) fn activate_entry(ui: &Rc<Ui>, entry: &DirEntry) {
 /// [`mounted_target`](crate::activation::mounted_target).
 pub(crate) fn download_and_open(ui: &Rc<Ui>, entry: &DirEntry) {
     let rel = entry_rel(ui, entry);
-    let mountpoint = ui.dirs.resolved_mountpoint(&ui.dirs.load_config());
-    if let Some(path) = mounted_target_rel(&mountpoint, &rel) {
-        open_path(&path.to_string_lossy());
-        return;
-    }
-    // Ignore a repeat activation of a file already downloading, so an impatient
-    // double-click doesn't kick off a second round-trip.
+    // Ignore a repeat activation of a file already opening, so an impatient
+    // double-click doesn't open it twice or kick off a second round-trip.
     if !ui.opening.borrow_mut().insert(rel.clone()) {
         return;
     }
-    ui.busy_begin();
-    let name = entry.name.clone();
-    let rx = spawn_request(
-        ui.dirs.control_socket(),
-        Request::OpenFile {
-            path: rel.clone(),
-            uid: Some(entry.uid.clone()),
-        },
-    );
+    let mountpoint = ui.dirs.resolved_mountpoint(&ui.dirs.load_config());
+    let (name, uid) = (entry.name.clone(), entry.uid.clone());
     let ui = ui.clone();
     glib::spawn_future_local(async move {
+        // Asked off the main thread: a mount that hangs used to hang the app.
+        if let Some(path) = present_within(mounted_path(&mountpoint, &rel)).await {
+            ui.opening.borrow_mut().remove(&rel);
+            open_path(&path.to_string_lossy());
+            return;
+        }
+        ui.busy_begin();
+        let rx = spawn_request(
+            ui.dirs.control_socket(),
+            Request::OpenFile {
+                path: rel.clone(),
+                uid: Some(uid),
+            },
+        );
         let result = rx.recv().await;
         ui.busy_end();
         ui.opening.borrow_mut().remove(&rel);
@@ -1147,6 +1222,7 @@ pub(crate) fn toggle_pin(ui: &Rc<Ui>, entry: &DirEntry) {
     let rx = spawn_request(ui.dirs.control_socket(), req);
     let name = entry.name.clone();
     let pinned = entry.pinned;
+    let is_dir = entry.is_dir;
     let ui = ui.clone();
     glib::spawn_future_local(async move {
         match rx.recv().await {
@@ -1166,6 +1242,9 @@ pub(crate) fn toggle_pin(ui: &Rc<Ui>, entry: &DirEntry) {
                     &ui,
                     &if pinned {
                         gettext_f("“{name}” is now online only", &[("name", &name)])
+                    } else if is_dir {
+                        // The daemon downloads a folder's files in the background.
+                        gettext_f("Making “{name}” available offline…", &[("name", &name)])
                     } else {
                         gettext_f("“{name}” is now available offline", &[("name", &name)])
                     },
@@ -1274,6 +1353,11 @@ pub(crate) fn wire_browser_actions(ui: &Rc<Ui>, build_thumbnails: &gtk4::Button)
 
     let view = ui.dirs.load_config().files_view;
     ui.browser.view.set(view);
+    if let Some(size) = view.icon_size {
+        ui.browser
+            .zoom
+            .set_value(f64::from(size.clamp(GRID_THUMB_MIN, GRID_THUMB_MAX)));
+    }
     let layout = gio::SimpleAction::new_stateful(
         "view",
         Some(glib::VariantTy::STRING),
@@ -1375,6 +1459,41 @@ pub(crate) fn wire_browser_actions(ui: &Rc<Ui>, build_thumbnails: &gtk4::Button)
     ui.browser.content.add_controller(drop);
 }
 
+/// Remember the grid's icon size, once the slider has rested for a moment.
+fn save_icon_size(ui: &Rc<Ui>, size: i32) {
+    let mut view = ui.browser.view.get();
+    if view.icon_size == Some(size) {
+        return;
+    }
+    view.icon_size = Some(size);
+    ui.browser.view.set(view);
+    if let Some(source) = ui.browser.zoom_save.borrow_mut().take() {
+        source.remove();
+    }
+    let ui_save = ui.clone();
+    let source = glib::timeout_add_local_once(Duration::from_millis(500), move || {
+        ui_save.browser.zoom_save.borrow_mut().take();
+        let mut config = ui_save.dirs.load_config();
+        config.files_view.icon_size = ui_save.browser.view.get().icon_size;
+        if let Err(e) = ui_save.dirs.save_config(&config) {
+            tracing::warn!("cannot save the icon size: {e}");
+        }
+    });
+    *ui.browser.zoom_save.borrow_mut() = Some(source);
+}
+
+/// Step the grid's icon size by `steps` slider notches; `0` resets it.
+pub(crate) fn zoom_files(ui: &Rc<Ui>, steps: i32) {
+    let zoom = &ui.browser.zoom;
+    let size = if steps == 0 {
+        GRID_THUMB_DEFAULT
+    } else {
+        (zoom.value().round() as i32 + steps * GRID_THUMB_STEP)
+            .clamp(GRID_THUMB_MIN, GRID_THUMB_MAX)
+    };
+    zoom.set_value(f64::from(size));
+}
+
 fn layout_name(view: FilesView) -> &'static str {
     if view.list { "list" } else { "grid" }
 }
@@ -1452,8 +1571,29 @@ pub(crate) fn sort_entries(entries: &mut [DirEntry], view: FilesView) {
     });
 }
 
+/// Remember how the folder on screen is scrolled and what is selected in it,
+/// for Back, Forward or Up to bring it back that way. Only a listing of the
+/// folder itself counts; search hits are not its rows.
+fn remember_place(ui: &Rc<Ui>) {
+    let path = ui.browser.path.borrow().clone();
+    if ui.browser.listed.borrow().as_deref() != Some(path.as_str()) {
+        return;
+    }
+    let files = &ui.browser.files;
+    let place = FolderPlace {
+        offset: files.scroll_offset(),
+        selected: files
+            .selected()
+            .into_iter()
+            .map(|entry| entry.name)
+            .collect(),
+    };
+    ui.browser.places.borrow_mut().insert(path, place);
+}
+
 /// Open the folder on screen in a new place, remembering where we were.
 pub(crate) fn browse_to(ui: &Rc<Ui>, target: String) {
+    remember_place(ui);
     let left = ui.browser.path.replace(target.clone());
     if left != target {
         ui.browser.history.borrow_mut().push(left);
@@ -1478,6 +1618,8 @@ fn browse_back(ui: &Rc<Ui>) {
     let Some(previous) = ui.browser.history.borrow_mut().pop() else {
         return;
     };
+    remember_place(ui);
+    *ui.browser.restore.borrow_mut() = Some(previous.clone());
     let left = ui.browser.path.replace(previous);
     ui.browser.future.borrow_mut().push(left);
     load_browser(ui);
@@ -1488,6 +1630,8 @@ fn browse_forward(ui: &Rc<Ui>) {
         return;
     };
     ui.browser.search.set_text("");
+    remember_place(ui);
+    *ui.browser.restore.borrow_mut() = Some(next.clone());
     let left = ui.browser.path.replace(next);
     ui.browser.history.borrow_mut().push(left);
     load_browser(ui);
@@ -1500,6 +1644,7 @@ fn browse_up(ui: &Rc<Ui>) {
     }
     ui.browser.search.set_text("");
     let parent = path.rfind('/').map(|i| &path[..i]).unwrap_or_default();
+    *ui.browser.restore.borrow_mut() = Some(parent.to_string());
     browse_to(ui, parent.to_string());
 }
 
@@ -1696,8 +1841,9 @@ fn repaint_thumbnail_build(ui: &Rc<Ui>, status: &ThumbnailBuildStatus) {
     let text = if status.scanning {
         ui.browser.thumbnail_progress.pulse();
         let folders = ngettext_f("{n} folder", "{n} folders", status.folders_scanned, &[]);
-        let images = ngettext_f("{n} image", "{n} images", status.images_found, &[]);
-        // Translators: {root} is a folder path or "Proton Drive"; {folders} and {images} are counts such as "3 folders" and "12 images".
+        // Translators: a count of images and videos that can have a thumbnail.
+        let images = ngettext_f("{n} file", "{n} files", status.images_found, &[]);
+        // Translators: {root} is a folder path or "Proton Drive"; {folders} and {images} are counts such as "3 folders" and "12 files".
         gettext_f(
             "Scanning {root}… {folders}, {images}",
             &[("root", root), ("folders", &folders), ("images", &images)],
@@ -1711,7 +1857,7 @@ fn repaint_thumbnail_build(ui: &Rc<Ui>, status: &ThumbnailBuildStatus) {
         ui.browser
             .thumbnail_progress
             .set_fraction(fraction.clamp(0.0, 1.0));
-        // Translators: {root} is a folder path or "Proton Drive"; {done} and {total} are image counts.
+        // Translators: {root} is a folder path or "Proton Drive"; {done} and {total} are counts of images and videos.
         gettext_f(
             "Building thumbnails in {root}… {done} of {total}",
             &[
@@ -1724,17 +1870,17 @@ fn repaint_thumbnail_build(ui: &Rc<Ui>, status: &ThumbnailBuildStatus) {
         ui.browser.thumbnail_progress.set_fraction(1.0);
         let available = status.completed.saturating_sub(status.failed);
         match status.failed {
-            // Translators: {root} is a folder path or "Proton Drive".
+            // Translators: {root} is a folder path or "Proton Drive"; {n} counts images and videos.
             0 => ngettext_f(
-                "Thumbnails ready for {n} image in {root}",
-                "Thumbnails ready for {n} images in {root}",
+                "Thumbnails ready for {n} file in {root}",
+                "Thumbnails ready for {n} files in {root}",
                 available,
                 &[("root", root)],
             ),
-            // Translators: {root} is a folder path or "Proton Drive"; {failed} is how many images could not get a thumbnail.
+            // Translators: {root} is a folder path or "Proton Drive"; {failed} is how many images and videos could not get a thumbnail.
             failed => ngettext_f(
-                "Thumbnails ready for {n} image in {root}; {failed} unavailable",
-                "Thumbnails ready for {n} images in {root}; {failed} unavailable",
+                "Thumbnails ready for {n} file in {root}; {failed} unavailable",
+                "Thumbnails ready for {n} files in {root}; {failed} unavailable",
                 available,
                 &[("root", root), ("failed", &failed.to_string())],
             ),
@@ -1918,17 +2064,63 @@ pub(crate) fn prompt_rename(ui: &Rc<Ui>, entry: &DirEntry) {
 /// still made on Proton Drive, so nothing is downloaded or uploaded again; it
 /// is sent with absolute paths, which is how the daemon tells locations apart.
 pub(crate) fn prompt_move(ui: &Rc<Ui>, entries: Vec<DirEntry>) {
+    prompt_destination(ui, entries, PickerKind::Move);
+}
+
+/// Ask where to copy `entries`, then copy them there on Proton Drive. Only
+/// My files is offered: a copy is made on the server, inside the mount.
+pub(crate) fn prompt_copy(ui: &Rc<Ui>, entries: Vec<DirEntry>) {
+    prompt_destination(ui, entries, PickerKind::Copy);
+}
+
+/// Copy one entry into the folder it is in. The copy gets a free name, such
+/// as "report (1).pdf".
+pub(crate) fn make_copy(ui: &Rc<Ui>, entry: &DirEntry) {
+    let source = entry_rel(ui, entry);
+    let parent = source
+        .rfind('/')
+        .map(|i| source[..i].to_string())
+        .unwrap_or_default();
+    run_bulk_copy(ui, vec![source], parent);
+}
+
+/// What the folder picker chooses a destination for.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub(crate) enum PickerKind {
+    Move,
+    Copy,
+}
+
+fn prompt_destination(ui: &Rc<Ui>, entries: Vec<DirEntry>, kind: PickerKind) {
     if entries.is_empty() {
         return;
     }
     let sources: Vec<String> = entries.iter().map(|e| entry_rel(ui, e)).collect();
-    let heading = match entries.as_slice() {
-        [one] => gettext_f("Move “{name}”", &[("name", &one.name)]),
-        many => ngettext_f("Move {n} item", "Move {n} items", many.len() as u64, &[]),
+    let (heading, body, confirm) = match (kind, entries.as_slice()) {
+        (PickerKind::Move, [one]) => (
+            gettext_f("Move “{name}”", &[("name", &one.name)]),
+            gettext("Choose the folder to move into."),
+            gettext("Move Here"),
+        ),
+        (PickerKind::Move, many) => (
+            ngettext_f("Move {n} item", "Move {n} items", many.len() as u64, &[]),
+            gettext("Choose the folder to move into."),
+            gettext("Move Here"),
+        ),
+        (PickerKind::Copy, [one]) => (
+            gettext_f("Copy “{name}”", &[("name", &one.name)]),
+            gettext("Choose the folder to copy into."),
+            gettext("Copy Here"),
+        ),
+        (PickerKind::Copy, many) => (
+            ngettext_f("Copy {n} item", "Copy {n} items", many.len() as u64, &[]),
+            gettext("Choose the folder to copy into."),
+            gettext("Copy Here"),
+        ),
     };
     let dialog = adw::AlertDialog::builder()
         .heading(heading)
-        .body(gettext("Choose the folder to move into."))
+        .body(body)
         .build();
 
     let up = gtk4::Button::builder()
@@ -1959,7 +2151,7 @@ pub(crate) fn prompt_move(ui: &Rc<Ui>, entries: Vec<DirEntry>) {
     body.append(&scroll);
     dialog.set_extra_child(Some(&body));
     dialog.add_response("cancel", &gettext("Cancel"));
-    dialog.add_response("move", &gettext("Move Here"));
+    dialog.add_response("move", &confirm);
     dialog.set_response_appearance("move", adw::ResponseAppearance::Suggested);
     dialog.set_default_response(Some("move"));
     dialog.set_close_response("cancel");
@@ -1972,6 +2164,7 @@ pub(crate) fn prompt_move(ui: &Rc<Ui>, entries: Vec<DirEntry>) {
         list,
         up: up.clone(),
         sources: sources.clone(),
+        kind,
         folder: RefCell::new(MoveTarget::Locations),
         generation: Cell::new(0),
     });
@@ -1991,6 +2184,10 @@ pub(crate) fn prompt_move(ui: &Rc<Ui>, entries: Vec<DirEntry>) {
         }
         match picker_done.folder.borrow().clone() {
             MoveTarget::Locations => {}
+            MoveTarget::Drive(folder) if kind == PickerKind::Copy => {
+                run_bulk_copy(&ui, sources.clone(), folder)
+            }
+            MoveTarget::Synced { .. } if kind == PickerKind::Copy => {}
             MoveTarget::Drive(folder) => run_bulk_move(&ui, sources.clone(), folder),
             MoveTarget::Synced { path, .. } => {
                 let absolute = sources
@@ -2066,8 +2263,9 @@ struct MovePicker {
     location: gtk4::Label,
     list: gtk4::ListBox,
     up: gtk4::Button,
-    /// What is being moved, mountpoint-relative.
+    /// What is being moved or copied, mountpoint-relative.
     sources: Vec<String>,
+    kind: PickerKind,
     /// The folder on show, and the destination if the user confirms now.
     folder: RefCell<MoveTarget>,
     /// Drops a listing that arrives after the user went elsewhere.
@@ -2088,11 +2286,13 @@ impl MovePicker {
         self.location.set_tooltip_text(Some(&tooltip));
         self.up
             .set_sensitive(!matches!(folder, MoveTarget::Locations));
-        let allowed = match &folder {
-            MoveTarget::Locations => false,
-            MoveTarget::Drive(rel) => move_target_allowed(&self.sources, rel),
+        let allowed = match (&folder, self.kind) {
+            (MoveTarget::Locations, _) => false,
+            (MoveTarget::Drive(rel), PickerKind::Move) => move_target_allowed(&self.sources, rel),
+            (MoveTarget::Drive(rel), PickerKind::Copy) => copy_target_allowed(&self.sources, rel),
             // What is moved is in My files, so it cannot be in a synced folder.
-            MoveTarget::Synced { .. } => true,
+            (MoveTarget::Synced { .. }, PickerKind::Move) => true,
+            (MoveTarget::Synced { .. }, PickerKind::Copy) => false,
         };
         self.dialog.set_response_enabled("move", allowed);
         *self.folder.borrow_mut() = folder.clone();
@@ -2158,6 +2358,10 @@ impl MovePicker {
     /// My files and every synced folder, as rows of the top level.
     async fn locations(&self) -> Option<Vec<PickerRow>> {
         let mut rows = vec![(gettext("My files"), None, MoveTarget::Drive(String::new()))];
+        // A copy is made on the server, so it can only land in My files.
+        if self.kind == PickerKind::Copy {
+            return Some(rows);
+        }
         let rx = spawn_request(self.ui.dirs.control_socket(), Request::ListSyncFolders);
         let Ok(Ok(Response::SyncFolders { mut items })) = rx.recv().await else {
             // My files alone is still somewhere to move to.
@@ -2264,11 +2468,16 @@ pub(crate) fn move_target_allowed(sources: &[String], target: &str) -> bool {
             .map(|i| path[..i].to_string())
             .unwrap_or_default()
     };
-    let inside = sources
-        .iter()
-        .any(|src| target == src || target.starts_with(&format!("{src}/")));
     let all_here = sources.iter().all(|src| parent(src) == target);
-    !inside && !all_here
+    copy_target_allowed(sources, target) && !all_here
+}
+
+/// Whether `target` is somewhere `sources` can be copied to: anywhere but into
+/// one of themselves. The folder they are in is fine; the copy gets a free name.
+pub(crate) fn copy_target_allowed(sources: &[String], target: &str) -> bool {
+    !sources
+        .iter()
+        .any(|src| target == src || target.starts_with(&format!("{src}/")))
 }
 
 /// Move each of `sources` into `target`, one request at a time, then report
@@ -2287,38 +2496,14 @@ pub(crate) fn run_bulk_move(ui: &Rc<Ui>, sources: Vec<String>, target: String) {
     clear_selection(ui);
     let ui = ui.clone();
     glib::spawn_future_local(async move {
-        let mut done = 0usize;
-        let mut failure: Option<(String, ErrorKind)> = None;
-        for path in sources {
-            let rx = spawn_request(
-                socket.clone(),
-                Request::Move {
-                    path,
-                    new_parent: target.clone(),
-                },
-            );
-            match rx.recv().await {
-                Ok(Ok(Response::Ok { .. })) => done += 1,
-                Ok(Ok(Response::Error { message, kind })) => {
-                    failure.get_or_insert((message, kind));
-                }
-                _ => {
-                    failure.get_or_insert_with(|| {
-                        (
-                            gettext("The Proton Drive service didn't respond."),
-                            ErrorKind::Internal,
-                        )
-                    });
-                }
-            }
-        }
+        let (done, failure) = send_each(&socket, sources, |path| Request::Move {
+            path,
+            new_parent: target.clone(),
+        })
+        .await;
         ui.busy_end();
         reload_listing(&ui);
-        let place = match target.rsplit('/').next() {
-            // Translators: a folder name in quotes, filled in as {place} in "Moved to {place}".
-            Some(name) if !name.is_empty() => gettext_f("“{name}”", &[("name", name)]),
-            _ => "Proton Drive".to_string(),
-        };
+        let place = quoted_place(&target);
         match (done, failure) {
             (0, Some((message, kind))) => {
                 toast_failure(&ui, &gettext("Couldn't move"), &message, kind)
@@ -2351,6 +2536,101 @@ pub(crate) fn run_bulk_move(ui: &Rc<Ui>, sources: Vec<String>, target: String) {
     });
 }
 
+/// Copy each of `sources` into `target` on Proton Drive, one request at a
+/// time, then report once for the lot.
+pub(crate) fn run_bulk_copy(ui: &Rc<Ui>, sources: Vec<String>, target: String) {
+    if !*ui.mounted.borrow() {
+        toast_error(
+            ui,
+            &gettext("Couldn't copy"),
+            &gettext("Proton Drive isn't connected."),
+        );
+        return;
+    }
+    let socket = ui.dirs.control_socket();
+    ui.busy_begin();
+    clear_selection(ui);
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let (done, failure) = send_each(&socket, sources, |path| Request::Copy {
+            path,
+            new_parent: target.clone(),
+        })
+        .await;
+        ui.busy_end();
+        reload_listing(&ui);
+        let place = quoted_place(&target);
+        match (done, failure) {
+            (0, Some((message, kind))) => {
+                toast_failure(&ui, &gettext("Couldn't copy"), &message, kind)
+            }
+            (0, None) => {}
+            (n, Some((message, _))) => toast_error(
+                &ui,
+                // Translators: {place} is a quoted folder name or "Proton Drive".
+                &ngettext_f(
+                    "Copied {n} item to {place}, but not all",
+                    "Copied {n} items to {place}, but not all",
+                    n as u64,
+                    &[("place", &place)],
+                ),
+                &message,
+            ),
+            // Translators: {place} is a quoted folder name or "Proton Drive".
+            (1, None) => toast(&ui, &gettext_f("Copied to {place}", &[("place", &place)])),
+            (n, None) => toast(
+                &ui,
+                // Translators: {place} is a quoted folder name or "Proton Drive".
+                &ngettext_f(
+                    "Copied {n} item to {place}",
+                    "Copied {n} items to {place}",
+                    n as u64,
+                    &[("place", &place)],
+                ),
+            ),
+        }
+    });
+}
+
+/// Send one request per source, in order, and count how many succeeded. The
+/// first failure is kept for the report.
+async fn send_each(
+    socket: &Path,
+    sources: Vec<String>,
+    request: impl Fn(String) -> Request,
+) -> (usize, Option<(String, ErrorKind)>) {
+    let mut done = 0usize;
+    let mut failure: Option<(String, ErrorKind)> = None;
+    for path in sources {
+        let rx = spawn_request(socket.to_path_buf(), request(path));
+        match rx.recv().await {
+            Ok(Ok(Response::Ok { .. })) => done += 1,
+            Ok(Ok(Response::Error { message, kind })) => {
+                failure.get_or_insert((message, kind));
+            }
+            _ => {
+                failure.get_or_insert_with(|| {
+                    (
+                        gettext("The Proton Drive service didn't respond."),
+                        ErrorKind::Internal,
+                    )
+                });
+            }
+        }
+    }
+    (done, failure)
+}
+
+/// The destination folder for a report: its name in quotes, or "Proton Drive"
+/// for My files.
+fn quoted_place(target: &str) -> String {
+    match target.rsplit('/').next() {
+        // Translators: a folder name in quotes, filled in as {place} in "Moved to {place}".
+        Some(name) if !name.is_empty() => gettext_f("“{name}”", &[("name", name)]),
+        _ => "Proton Drive".to_string(),
+    }
+}
+
 /// Move one entry to Trash, through the batch path so it gets the same Undo.
 pub(crate) fn trash_entry(ui: &Rc<Ui>, entry: &DirEntry) {
     run_bulk_delete(ui, vec![entry.clone()]);
@@ -2487,16 +2767,19 @@ pub(crate) fn start_upload(ui: &Rc<Ui>, sources: Vec<String>) {
     });
 }
 
-/// The sync-state badge for an entry: `(icon, css-class)`, or `None` for folders
-/// (which carry no per-file cache state). A sync issue ranks first, on folders
-/// too: the change waits for the user. Pinned (kept offline) ranks above merely
-/// cached (downloaded, evictable); everything else is online-only.
+/// The sync-state badge for an entry: `(icon, css-class)`. A folder carries no
+/// cache state of its own, so it has one only when kept offline. A sync issue
+/// ranks first, on folders too: the change waits for the user. Pinned (kept
+/// offline) ranks above merely cached (downloaded, evictable); everything else
+/// is online-only.
 pub(crate) fn badge_for(entry: &DirEntry) -> Option<(&'static str, &'static str)> {
     if entry.issue.is_some() {
         return Some(("dialog-warning-symbolic", "badge-issue"));
     }
     if entry.is_dir {
-        return None;
+        return entry
+            .pinned
+            .then_some(("pdfs-offline-symbolic", "badge-pinned"));
     }
     Some(if entry.pinned {
         ("pdfs-offline-symbolic", "badge-pinned")
@@ -2596,6 +2879,11 @@ pub(crate) fn icon_base_for(entry: &DirEntry) -> &'static str {
     if entry.is_dir {
         return "folder";
     }
+    // Every video type, including a `.ts` recording, which by its name alone
+    // is TypeScript.
+    if pdfs_core::control::is_video_file_name(&entry.name, Some(entry.size)) {
+        return "video-x-generic";
+    }
     let ext = entry
         .name
         .rsplit('.')
@@ -2606,7 +2894,6 @@ pub(crate) fn icon_base_for(entry: &DirEntry) -> &'static str {
         "png" | "jpg" | "jpeg" | "gif" | "webp" | "bmp" | "svg" | "heic" | "tiff" => {
             "image-x-generic"
         }
-        "mp4" | "mkv" | "mov" | "avi" | "webm" | "m4v" => "video-x-generic",
         "mp3" | "flac" | "wav" | "ogg" | "opus" | "m4a" => "audio-x-generic",
         "pdf" | "doc" | "docx" | "odt" => "x-office-document",
         "xls" | "xlsx" | "ods" | "csv" => "x-office-spreadsheet",
@@ -2675,6 +2962,18 @@ pub(crate) fn load_browser(ui: &Rc<Ui>) {
     });
 }
 
+/// Read again what My files shows: the search hits while there is a query,
+/// the folder otherwise. [`load_browser`] alone would swap a search's hits
+/// for the folder while the query stays in the box.
+pub(crate) fn reload_browser_view(ui: &Rc<Ui>) {
+    let query = ui.browser.search.text().trim().to_string();
+    if query.is_empty() {
+        load_browser(ui);
+    } else {
+        run_search(ui, &query);
+    }
+}
+
 /// Clear the model and show the daemon's error on the status page. Used for
 /// in-band failures (a bad path, a permission error) — the mount is up, so Retry
 /// (which restarts the service) wouldn't help and isn't offered.
@@ -2713,7 +3012,10 @@ pub(crate) fn browser_unreachable(ui: &Rc<Ui>) {
 pub(crate) fn repaint_browser(ui: &Rc<Ui>, entries: &[DirEntry]) {
     show_location_column(ui, false);
     *ui.browser.listing.borrow_mut() = entries.to_vec();
-    *ui.browser.listed.borrow_mut() = Some(ui.browser.path.borrow().clone());
+    // `listed` still names the folder the rows belong to only on a refresh;
+    // any other load forgot it (see `load_browser`).
+    let path = ui.browser.path.borrow().clone();
+    let another_folder = ui.browser.listed.replace(Some(path.clone())).as_ref() != Some(&path);
     ui.browser.summary.set_label(&listing_summary(
         entries.iter().filter(|entry| !entry.is_dir).count(),
         entries.iter().filter(|entry| entry.is_dir).count(),
@@ -2742,6 +3044,16 @@ pub(crate) fn repaint_browser(ui: &Rc<Ui>, entries: &[DirEntry]) {
     // Only the rows that changed are swapped, so a refresh keeps the
     // selection, the scroll position and the thumbnails already drawn.
     replace_items(&ui.browser.files.model, &sorted);
+    // Back, Forward and Up return to a folder as it was left; any other way
+    // in starts at the top.
+    let restore = ui.browser.restore.take().filter(|target| *target == path);
+    if another_folder {
+        let place = restore.and_then(|path| ui.browser.places.borrow().get(&path).cloned());
+        match place {
+            Some(place) => ui.browser.files.restore(place.offset, &place.selected),
+            None => ui.browser.files.scroll_to_top(),
+        }
+    }
 }
 
 /// Forget which folder the rows belong to and drop the selection, before the
@@ -2905,6 +3217,7 @@ pub(crate) fn repaint_search(ui: &Rc<Ui>, hits: &[SearchHit]) {
             size: h.size,
             modified: h.modified,
             pinned: h.pinned,
+            pinned_by_folder: false,
             cached: h.cached,
             uid: h.uid.clone(),
             path: h.path.clone(),
@@ -2919,6 +3232,9 @@ pub(crate) fn repaint_search(ui: &Rc<Ui>, hits: &[SearchHit]) {
         .collect();
     sort_entries(&mut entries, ui.browser.view.get());
     replace_items(&ui.browser.files.model, &entries);
+    // Every search starts over (`run_search` forgets the listing), so its hits
+    // read from the first one.
+    ui.browser.files.scroll_to_top();
 }
 
 fn listing_summary(files: usize, folders: usize, file_bytes: u64) -> String {
@@ -2952,8 +3268,8 @@ fn listing_summary(files: usize, folders: usize, file_bytes: u64) -> String {
 #[cfg(test)]
 mod tests {
     use super::{
-        MoveTarget, badge_for, hit_location, listing_summary, move_target_allowed,
-        show_thumbnail_build_progress, sort_entries,
+        MoveTarget, badge_for, copy_target_allowed, hit_location, icon_base_for, listing_summary,
+        move_target_allowed, show_thumbnail_build_progress, sort_entries,
     };
     use pdfs_core::config::{FileSort, FilesView};
     use pdfs_core::control::{DirEntry, SyncIssue, ThumbnailBuildStatus};
@@ -2965,6 +3281,7 @@ mod tests {
             size,
             modified,
             pinned: false,
+            pinned_by_folder: false,
             cached: false,
             uid: String::new(),
             path: String::new(),
@@ -2978,6 +3295,32 @@ mod tests {
         }
     }
 
+    #[test]
+    fn every_video_type_gets_the_video_icon() {
+        const MIB: u64 = 1024 * 1024;
+        for name in [
+            "clip.mp4",
+            "clip.MKV",
+            "broadcast.m2ts",
+            "camera.mts",
+            "old.flv",
+        ] {
+            assert_eq!(
+                icon_base_for(&entry(name, false, 10, 0)),
+                "video-x-generic",
+                "{name}"
+            );
+        }
+        assert_eq!(
+            icon_base_for(&entry("recording.ts", false, 900 * MIB, 0)),
+            "video-x-generic"
+        );
+        assert_eq!(
+            icon_base_for(&entry("app.ts", false, 4096, 0)),
+            "text-x-generic"
+        );
+    }
+
     fn names(entries: &[DirEntry]) -> Vec<&str> {
         entries.iter().map(|e| e.name.as_str()).collect()
     }
@@ -2992,6 +3335,8 @@ mod tests {
 
         let mut folder = entry("d", true, 0, 0);
         assert_eq!(badge_for(&folder), None);
+        folder.pinned = true;
+        assert_eq!(badge_for(&folder).unwrap().1, "badge-pinned");
         folder.issue = Some(SyncIssue::Missing);
         assert_eq!(badge_for(&folder).unwrap().1, "badge-issue");
     }
@@ -3038,6 +3383,16 @@ mod tests {
         assert!(move_target_allowed(&mixed, ""));
     }
 
+    #[test]
+    fn copy_refuses_its_own_subtree_but_not_the_folder_it_is_in() {
+        let sources = ["Docs/Work".to_string()];
+        assert!(!copy_target_allowed(&sources, "Docs/Work"));
+        assert!(!copy_target_allowed(&sources, "Docs/Work/Old"));
+        assert!(copy_target_allowed(&sources, "Docs"));
+        assert!(copy_target_allowed(&sources, ""));
+        assert!(copy_target_allowed(&sources, "Docs/Workshop"));
+    }
+
     #[test]
     fn listing_summary_matches_dolphin_order_and_wording() {
         assert_eq!(listing_summary(0, 0, 0), "0 folders, 0 files");

crates/pdfs-gui/src/app/pages/devices.rs

@@ -190,10 +190,9 @@ pub(crate) fn wire_devices(ui: &Rc<Ui>, widgets: &DevicesWidgets) {
         }));
 
     let ui_back = ui.clone();
-    widgets.back.connect_clicked(move |_| {
-        ui_back.devices.nav.borrow_mut().pop();
-        load_devices(&ui_back);
-    });
+    widgets
+        .back
+        .connect_clicked(move |_| devices_back(&ui_back));
     let ui_retry = ui.clone();
     widgets
         .retry
@@ -204,11 +203,21 @@ pub(crate) fn wire_devices(ui: &Rc<Ui>, widgets: &DevicesWidgets) {
 pub(crate) fn devices_status(ui: &Rc<Ui>, icon: &str, title: &str, description: &str, retry: bool) {
     ui.devices.status.set_icon_name(Some(icon));
     ui.devices.status.set_title(title);
-    ui.devices.status.set_description(Some(description));
+    ui.devices
+        .status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.devices.retry.set_visible(retry);
     ui.devices.content.set_visible_child_name("status");
 }
 
+/// Back out of a computer's folder to the level above: the page's Back button, and
+/// Alt+Left or Backspace. A no-op at the top.
+pub(crate) fn devices_back(ui: &Rc<Ui>) {
+    if ui.devices.nav.borrow_mut().pop().is_some() {
+        load_devices(ui);
+    }
+}
+
 /// Load the view [`DevicesState::nav`] points at: the device list, or a folder
 /// of another computer's backup.
 pub(crate) fn load_devices(ui: &Rc<Ui>) {
@@ -295,6 +304,7 @@ fn load_device_folder(ui: &Rc<Ui>, nav: &[(String, String)]) {
         };
         ui.devices.content.set_visible_child_name("browse");
         repaint_device_crumb(&ui, &nav);
+        let another_folder = ui.devices.listed.borrow().as_ref() != Some(&nav);
         *ui.devices.listed.borrow_mut() = Some(nav);
         if entries.is_empty() {
             ui.devices.files.model.remove_all();
@@ -302,6 +312,10 @@ fn load_device_folder(ui: &Rc<Ui>, nav: &[(String, String)]) {
         } else {
             ui.devices.files_content.set_visible_child_name("list");
             replace_items(&ui.devices.files.model, &entries);
+            // A refresh keeps its place; another folder starts at the top.
+            if another_folder {
+                ui.devices.files.scroll_to_top();
+            }
         }
     });
 }
@@ -390,6 +404,7 @@ fn this_computer_row(
     let row = adw::ActionRow::builder()
         .title(me.map_or_else(|| gettext("This computer"), |d| d.name.clone()))
         .subtitle(this_computer_subtitle(folders))
+        .use_markup(false)
         .activatable(true)
         .build();
     row.add_prefix(&gtk4::Image::from_icon_name("computer-symbolic"));
@@ -426,6 +441,7 @@ fn other_computer_row(ui: &Rc<Ui>, dev: &DeviceInfo) -> adw::ActionRow {
     let row = adw::ActionRow::builder()
         .title(&dev.name)
         .subtitle(device_subtitle(dev))
+        .use_markup(false)
         .activatable(true)
         .build();
     row.add_prefix(&gtk4::Image::from_icon_name("computer-symbolic"));
@@ -440,6 +456,10 @@ fn other_computer_row(ui: &Rc<Ui>, dev: &DeviceInfo) -> adw::ActionRow {
         prompt_restore_folders(&ui_c, Some((uid_c.clone(), name_c.clone())))
     });
     let (ui_c, uid_c, name_c) = (ui.clone(), uid.clone(), name.clone());
+    menu.item(&gettext("Sync With This Computer…"), move || {
+        prompt_join_device(&ui_c, &uid_c, &name_c)
+    });
+    let (ui_c, uid_c, name_c) = (ui.clone(), uid.clone(), name.clone());
     menu.item(&gettext("Move to This Computer…"), move || {
         prompt_migrate_device(&ui_c, &uid_c, &name_c)
     });
@@ -580,6 +600,7 @@ fn platform_label(device_type: &str) -> &str {
 /// How many folders this machine backs up, and whether any of them needs
 /// attention — the one fact worth surfacing away from the folder list itself.
 pub(crate) fn this_computer_subtitle(folders: &[SyncFolderInfo]) -> String {
+    let folders: Vec<_> = folders.iter().filter(|f| f.kind == "device").collect();
     if folders.is_empty() {
         return gettext("No folders backed up yet");
     }
@@ -589,6 +610,19 @@ pub(crate) fn this_computer_subtitle(folders: &[SyncFolderInfo]) -> String {
         folders.len() as u64,
         &[],
     );
+    // A folder whose first pass has not run is not backed up yet, whatever its
+    // state column says (`docs/BUGS.md` B261).
+    let waiting = folders.iter().filter(|f| never_synced(f)).count();
+    let count = match waiting {
+        0 => count,
+        // Translators: {folders} is "N folders backed up"; {n} counts the folders whose first sync has not run yet.
+        n => ngettext_f(
+            "{folders} · {n} waiting for its first sync",
+            "{folders} · {n} waiting for their first sync",
+            n as u64,
+            &[("folders", &count)],
+        ),
+    };
     let attention = folders
         .iter()
         .filter(|f| f.state == "error" || f.state == "conflict")
@@ -605,12 +639,21 @@ pub(crate) fn this_computer_subtitle(folders: &[SyncFolderInfo]) -> String {
     }
 }
 
-/// Human label for a synced folder's `state` column.
-pub(crate) fn sync_state_label(state: &str) -> String {
+/// Whether a synced folder is a mirror whose first pass has not finished.
+/// Its `state` starts out `idle`, which would read as "up to date".
+fn never_synced(folder: &SyncFolderInfo) -> bool {
+    folder.mode == "mirror" && folder.last_sync == 0 && folder.state == "idle"
+}
+
+/// Human label for a synced folder's `state` column. `never_synced` is a
+/// mirror folder whose first pass has not finished: its `state` starts out
+/// `idle`, and "up to date" would say the opposite of the truth (B261).
+pub(crate) fn sync_state_label(state: &str, never_synced: bool) -> String {
     match state {
         "syncing" => gettext("syncing…"),
         "error" => gettext("sync error"),
         "conflict" => gettext("needs attention"),
+        _ if never_synced => gettext("waiting for first sync"),
         _ => gettext("up to date"),
     }
 }
@@ -621,9 +664,17 @@ pub(crate) fn sync_state_label(state: &str) -> String {
 /// — so both read "12 of 40" rather than a percentage that could go backwards.
 pub(crate) fn sync_progress_label(p: &SyncProgress) -> String {
     match p.phase {
-        // Before the first pass finishes there is no estimate, so the count would
-        // be "checked 12 of 12" — worse than saying nothing.
-        SyncPhase::Scanning if p.total == 0 => gettext("checking for changes…"),
+        SyncPhase::Scanning if p.total == 0 && p.done == 0 => gettext("checking for changes…"),
+        // Before the first pass finishes there is no estimate, so "12 of 12" would
+        // say nothing. The count alone still shows a first scan of a large folder
+        // moving, which can take many minutes before anything downloads.
+        // Translators: {n} counts the folders and files checked so far.
+        SyncPhase::Scanning if p.total == 0 => ngettext_f(
+            "checking for changes — {n} item checked",
+            "checking for changes — {n} items checked",
+            p.done as u64,
+            &[],
+        ),
         // Translators: {done} and {total} count folders and files checked so far.
         SyncPhase::Scanning => gettext_f(
             "checking for changes — {done} of {total}",
@@ -763,7 +814,10 @@ fn show_restore_picker(
             .active(true)
             .valign(gtk4::Align::Center)
             .build();
-        let row = adw::EntryRow::builder().title(&f.name).build();
+        let row = adw::EntryRow::builder()
+            .title(&f.name)
+            .use_markup(false)
+            .build();
         row.set_text(&f.local_path);
         row.add_prefix(&check);
         group.add(&row);
@@ -898,7 +952,13 @@ pub(crate) fn reload_sync_pages(ui: &Rc<Ui>) {
 }
 
 /// Confirm, then stop syncing a folder. Offers to also delete the cloud copy.
-pub(crate) fn prompt_remove_sync_folder(ui: &Rc<Ui>, id: i64, path: &str, ondemand: bool) {
+pub(crate) fn prompt_remove_sync_folder(
+    ui: &Rc<Ui>,
+    id: i64,
+    path: &str,
+    ondemand: bool,
+    attached: bool,
+) {
     let win = ui_window(ui);
     // The two modes leave the user in opposite places, so they can't share a
     // sentence. A mirror folder's files are already on this disk and stay there.
@@ -906,7 +966,12 @@ pub(crate) fn prompt_remove_sync_folder(ui: &Rc<Ui>, id: i64, path: &str, ondema
     // in Proton Drive, so unmounting it leaves an empty directory — which is a
     // nasty surprise if the dialog claimed the local files were safe, and is
     // recoverable only by turning On-demand off *first* and letting it download.
-    let body = if ondemand {
+    let body = if attached {
+        gettext_f(
+            "Stop syncing “{path}”? Both the local files and the folder in My files are kept.",
+            &[("path", path)],
+        )
+    } else if ondemand {
         // Translators: {path} is a local folder path.
         gettext_f(
             "Stop syncing “{path}”?\n\nThis folder is online only: its files live in Proton Drive, not on this disk, so the folder will be empty once it stops syncing. To keep a local copy, cancel, switch the folder to Synced, and wait for the download to finish before removing it.",
@@ -934,7 +999,9 @@ pub(crate) fn prompt_remove_sync_folder(ui: &Rc<Ui>, id: i64, path: &str, ondema
         .active(false)
         .build();
     group.add(&delete_remote);
-    dialog.set_extra_child(Some(&group));
+    if !attached {
+        dialog.set_extra_child(Some(&group));
+    }
     dialog.add_response("cancel", &gettext("Cancel"));
     dialog.add_response("remove", &gettext("Stop Syncing"));
     dialog.set_response_appearance("remove", adw::ResponseAppearance::Destructive);
@@ -947,7 +1014,7 @@ pub(crate) fn prompt_remove_sync_folder(ui: &Rc<Ui>, id: i64, path: &str, ondema
                 &ui,
                 Request::RemoveSyncFolder {
                     id,
-                    delete_remote: delete_remote.is_active(),
+                    delete_remote: !attached && delete_remote.is_active(),
                 },
                 &gettext("Stopped syncing folder"),
                 &gettext("Couldn't stop syncing the folder"),
@@ -1093,6 +1160,69 @@ pub(crate) fn prompt_adopt_device(ui: &Rc<Ui>, uid: &str, name: &str) {
     dialog.present(win.as_ref());
 }
 
+/// Ask before syncing into another computer's device alongside it, then offer
+/// its folders for syncing here.
+///
+/// The same adoption as "Continue This Backup Here", but the other computer
+/// goes on syncing, so the dialog says what that means: the two keep the same
+/// folders in step, deletions included.
+pub(crate) fn prompt_join_device(ui: &Rc<Ui>, uid: &str, name: &str) {
+    let win = ui_window(ui);
+    let dialog = adw::AlertDialog::builder()
+        .heading(gettext("Sync With This Computer?"))
+        // Translators: {name} is the name of the other computer this one syncs with.
+        .body(gettext_f(
+            "This computer and “{name}” keep the same folders in step. A change or a deletion on one reaches the other.\n\nNew synced folders on this computer go under “{name}” in Proton Drive. Folders already synced here stay where they are. Next you choose which of its folders to sync here.",
+            &[("name", name)],
+        ))
+        .build();
+    dialog.add_response("cancel", &gettext("Cancel"));
+    dialog.add_response("join", &gettext("Sync Here"));
+    dialog.set_response_appearance("join", adw::ResponseAppearance::Suggested);
+    dialog.set_default_response(Some("cancel"));
+    dialog.set_close_response("cancel");
+    let ui = ui.clone();
+    let uid = uid.to_string();
+    // Translators: {name} is the name of the other computer this one now syncs with.
+    let done = gettext_f("Now syncing with “{name}”", &[("name", name)]);
+    dialog.connect_response(None, move |_, resp| {
+        if resp != "join" {
+            return;
+        }
+        ui.busy_begin();
+        let rx = spawn_request(
+            ui.dirs.control_socket(),
+            Request::AdoptDevice {
+                uid: Some(uid.clone()),
+            },
+        );
+        let (ui, done) = (ui.clone(), done.clone());
+        glib::spawn_future_local(async move {
+            let result = rx.recv().await;
+            ui.busy_end();
+            let failed = gettext("Couldn't sync with that computer");
+            match result {
+                Ok(Ok(Response::Ok { .. })) => {
+                    reload_sync_pages(&ui);
+                    toast(&ui, &done);
+                    // The device is this computer's now, so its own restore
+                    // picker offers the folders.
+                    prompt_restore_folders(&ui, None);
+                }
+                Ok(Ok(Response::Error { message, kind })) => {
+                    toast_failure(&ui, &failed, &message, kind)
+                }
+                _ => toast_error(
+                    &ui,
+                    &failed,
+                    &gettext("The Proton Drive service didn't respond."),
+                ),
+            }
+        });
+    });
+    dialog.present(win.as_ref());
+}
+
 /// Ask before moving another computer's folders into this computer's backup,
 /// then offer them for syncing here.
 ///
@@ -1187,23 +1317,61 @@ mod tests {
 
     fn folder(state: &str) -> SyncFolderInfo {
         SyncFolderInfo {
+            kind: "device".into(),
             id: 1,
             local_path: "/home/u/Documents".into(),
             remote_uid: "vol~link".into(),
             mode: "mirror".into(),
             state: state.into(),
-            last_sync: 0,
+            last_sync: 1_700_000_000,
             pending_mode: None,
             progress: None,
             paused: false,
         }
     }
 
+    #[test]
+    fn attached_my_files_folders_do_not_count_as_device_backups() {
+        let mut attached = folder("error");
+        attached.kind = "attached".into();
+        assert_eq!(
+            this_computer_subtitle(&[attached]),
+            "No folders backed up yet"
+        );
+    }
+
     #[test]
     fn a_machine_with_no_folders_says_so() {
         assert_eq!(this_computer_subtitle(&[]), "No folders backed up yet");
     }
 
+    /// A folder added a moment ago is not backed up yet, and the row must not
+    /// say it is (`docs/BUGS.md` B261). An on-demand folder has no first sync.
+    #[test]
+    fn a_folder_before_its_first_sync_is_not_counted_as_backed_up() {
+        let new = SyncFolderInfo {
+            last_sync: 0,
+            ..folder("idle")
+        };
+        assert_eq!(
+            this_computer_subtitle(&[folder("idle"), new.clone()]),
+            "2 folders backed up · 1 waiting for its first sync"
+        );
+        let failed = SyncFolderInfo {
+            state: "error".into(),
+            ..new.clone()
+        };
+        assert_eq!(
+            this_computer_subtitle(&[new.clone(), failed]),
+            "2 folders backed up · 1 waiting for its first sync · 1 needs attention"
+        );
+        let on_demand = SyncFolderInfo {
+            mode: "ondemand".into(),
+            ..new
+        };
+        assert_eq!(this_computer_subtitle(&[on_demand]), "1 folder backed up");
+    }
+
     #[test]
     fn folders_needing_attention_are_counted_not_hidden() {
         // The per-folder rows live on the Sync page, so this row is the only
@@ -1222,6 +1390,37 @@ mod tests {
         );
     }
 
+    fn scanning(done: usize, total: usize) -> SyncProgress {
+        SyncProgress {
+            phase: SyncPhase::Scanning,
+            done,
+            total,
+            current: String::new(),
+        }
+    }
+
+    #[test]
+    fn a_first_scan_counts_what_it_checked() {
+        // A first sync of a large folder scans for many minutes before anything
+        // downloads; without a count it reads as stuck (#46).
+        assert_eq!(
+            sync_progress_label(&scanning(0, 0)),
+            "checking for changes…"
+        );
+        assert_eq!(
+            sync_progress_label(&scanning(1, 0)),
+            "checking for changes — 1 item checked"
+        );
+        assert_eq!(
+            sync_progress_label(&scanning(1234, 0)),
+            "checking for changes — 1234 items checked"
+        );
+        assert_eq!(
+            sync_progress_label(&scanning(12, 40)),
+            "checking for changes — 12 of 40"
+        );
+    }
+
     #[test]
     fn the_restore_picker_names_the_computer_it_restores_from() {
         assert!(restore_picker_body(Some("laptop")).contains("“laptop”"));

crates/pdfs-gui/src/app/pages/duplicates.rs

@@ -209,7 +209,8 @@ fn ask(view: &Rc<FinderView>, finder: Finder, generation: u32) {
             Ok(Ok(Response::Error { message, .. })) => {
                 view.status.set_icon_name(Some("dialog-warning-symbolic"));
                 view.status.set_title(&failed);
-                view.status.set_description(Some(&message));
+                view.status
+                    .set_description(Some(&gtk4::glib::markup_escape_text(&message)));
                 view.progress.set_visible(false);
                 return;
             }

crates/pdfs-gui/src/app/pages/locations.rs

@@ -48,6 +48,8 @@ pub(crate) struct SyncCard {
     pub(crate) paused: Cell<bool>,
     /// Shown only while Proton refuses the session; opens the sign-in page.
     pub(crate) sign_in: gtk4::Button,
+    /// Shown only while the daemon is older than the app; restarts it.
+    pub(crate) restart: gtk4::Button,
 }
 
 /// What a folder row's controls are built from. The subtitle and progress bar
@@ -111,6 +113,7 @@ pub(crate) struct LocationsWidgets {
     pub(crate) card_title: gtk4::Label,
     pub(crate) card_detail: gtk4::Label,
     pub(crate) card_sign_in: gtk4::Button,
+    pub(crate) card_restart: gtk4::Button,
     pub(crate) pause: adw::SplitButton,
     pub(crate) queue_group: adw::PreferencesGroup,
     pub(crate) retry_all: gtk4::Button,
@@ -137,7 +140,7 @@ pub(crate) fn build_locations_page(history: &gtk4::Widget) -> (gtk4::Widget, Loc
         .build();
     add_folder.add_css_class("flat");
     let transfers_group = build_transfers_group();
-    let (card, card_icon, card_title, card_detail, card_sign_in) = build_sync_card();
+    let (card, card_icon, card_title, card_detail, card_sign_in, card_restart) = build_sync_card();
     let pause = build_pause_button();
     let (queue_group, retry_all) = build_queue_group();
     let conflicts_group = adw::PreferencesGroup::builder()
@@ -257,6 +260,7 @@ pub(crate) fn build_locations_page(history: &gtk4::Widget) -> (gtk4::Widget, Loc
         card_title,
         card_detail,
         card_sign_in,
+        card_restart,
         pause,
         queue_group,
         retry_all,
@@ -299,6 +303,11 @@ pub(crate) fn wire_locations(ui: &Rc<Ui>, retry: &gtk4::Button, add_folder: &gtk
         .card
         .sign_in
         .connect_clicked(move |_| show_login(&ui_sign_in));
+    let ui_restart = ui.clone();
+    ui.locations
+        .card
+        .restart
+        .connect_clicked(move |_| restart_service_then(&ui_restart, |_| {}));
     let ui_retry = ui.clone();
     ui.locations
         .queue
@@ -396,6 +405,7 @@ fn build_sync_card() -> (
     gtk4::Label,
     gtk4::Label,
     gtk4::Button,
+    gtk4::Button,
 ) {
     let icon = gtk4::Image::builder()
         .icon_name("pdfs-sync-symbolic")
@@ -430,10 +440,18 @@ fn build_sync_card() -> (
         .build();
     sign_in.add_css_class("pill");
     sign_in.add_css_class("suggested-action");
+    let restart = gtk4::Button::builder()
+        .label(gettext("Restart"))
+        .valign(gtk4::Align::Center)
+        .visible(false)
+        .build();
+    restart.add_css_class("pill");
+    restart.add_css_class("suggested-action");
     card.append(&icon);
     card.append(&text);
     card.append(&sign_in);
-    (card, icon, title, detail, sign_in)
+    card.append(&restart);
+    (card, icon, title, detail, sign_in, restart)
 }
 
 /// Pause/Resume, with timed pauses in its menu.
@@ -1127,7 +1145,9 @@ pub(crate) fn locations_status(
 ) {
     ui.locations.status.set_icon_name(Some(icon));
     ui.locations.status.set_title(title);
-    ui.locations.status.set_description(Some(description));
+    ui.locations
+        .status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.locations.retry.set_visible(retry);
     ui.locations.content.set_visible_child_name("status");
 }
@@ -1341,6 +1361,9 @@ fn location_row(ui: &Rc<Ui>, spec: &MountSpec) -> LocationRow {
                 prompt_mountpoint(&ui)
             });
         }
+        MountKind::Attached { sync_folder_id } => {
+            add_device_items(ui, &mut menu, spec, *sync_folder_id);
+        }
         MountKind::Device { sync_folder_id } => {
             row.add_suffix(&mode_button(ui, spec, *sync_folder_id));
             add_device_items(ui, &mut menu, spec, *sync_folder_id);
@@ -1486,8 +1509,13 @@ fn add_device_items(ui: &Rc<Ui>, menu: &mut ActionMenu, spec: &MountSpec, id: i6
         } else {
             gettext("Pause Syncing")
         };
+        let ui_pause = ui.clone();
+        menu.item(&label, move || set_folder_paused(&ui_pause, id, !paused));
         let ui = ui.clone();
-        menu.item(&label, move || set_folder_paused(&ui, id, !paused));
+        let path = spec.local_path.clone();
+        menu.item(&gettext("Sync From Scratch…"), move || {
+            confirm_reset_sync_folder(&ui, id, &path)
+        });
         menu.section();
     }
     let ui = ui.clone();
@@ -1495,8 +1523,54 @@ fn add_device_items(ui: &Rc<Ui>, menu: &mut ActionMenu, spec: &MountSpec, id: i6
     // The folder's *current* mode, not a queued one: a switch that hasn't landed
     // yet has not moved the files anywhere.
     let is_ondemand = spec.mode == MountMode::OnDemand;
+    let attached = matches!(spec.kind, MountKind::Attached { .. });
     menu.item(&gettext("Stop Syncing…"), move || {
-        prompt_remove_sync_folder(&ui, id, &path, is_ondemand)
+        prompt_remove_sync_folder(&ui, id, &path, is_ondemand, attached)
+    });
+}
+
+/// Ask before syncing a folder from scratch. Nothing is deleted, but files
+/// that differ come back as conflict copies, so it is not a click to make by
+/// accident.
+fn confirm_reset_sync_folder(ui: &Rc<Ui>, id: i64, path: &str) {
+    let dialog = adw::AlertDialog::builder()
+        .heading(gettext("Sync From Scratch?"))
+        // Translators: {path} is a local folder path.
+        .body(gettext_f("This computer forgets what it synced in {path} before and compares the folder with Proton Drive again. Nothing is deleted: a file on one side only is copied to the other, and a file that differs keeps both versions.", &[("path", path)]))
+        .build();
+    dialog.add_response("cancel", &gettext("Cancel"));
+    dialog.add_response("reset", &gettext("Sync From Scratch"));
+    dialog.set_response_appearance("reset", adw::ResponseAppearance::Suggested);
+    dialog.set_default_response(Some("cancel"));
+    dialog.set_close_response("cancel");
+    let win = ui_window(ui);
+    let ui = ui.clone();
+    dialog.connect_response(None, move |_, response| {
+        if response == "reset" {
+            reset_sync_folder(&ui, id);
+        }
+    });
+    dialog.present(win.as_ref());
+}
+
+/// Forget a folder's sync records, then repaint so its row shows the new pass.
+fn reset_sync_folder(ui: &Rc<Ui>, id: i64) {
+    let rx = spawn_request(ui.dirs.control_socket(), Request::ResetSyncFolder { id });
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let failed = gettext("Couldn't sync the folder from scratch");
+        match rx.recv().await {
+            Ok(Ok(Response::Ok { .. })) => toast(&ui, &gettext("Syncing folder…")),
+            Ok(Ok(Response::Error { message, kind })) => {
+                toast_failure(&ui, &failed, &message, kind)
+            }
+            _ => toast_error(
+                &ui,
+                &failed,
+                &gettext("The Proton Drive service didn't respond."),
+            ),
+        }
+        refresh_locations(&ui);
     });
 }
 
@@ -1629,7 +1703,7 @@ fn sync_folder_now(ui: &Rc<Ui>, id: i64) {
 pub(crate) fn location_icon(kind: &MountKind) -> &'static str {
     match kind {
         MountKind::MyFiles => "folder-remote-symbolic",
-        MountKind::Device { .. } => "folder-symbolic",
+        MountKind::Device { .. } | MountKind::Attached { .. } => "folder-symbolic",
         MountKind::Shared { .. } => "pdfs-people-symbolic",
     }
 }
@@ -1646,6 +1720,7 @@ pub(crate) fn location_subtitle(spec: &MountSpec) -> String {
     match &spec.kind {
         MountKind::MyFiles => parts.push(gettext("My files")),
         MountKind::Shared { .. } => parts.push(gettext("Shared folder")),
+        MountKind::Attached { .. } => parts.push(gettext("My files mirror")),
         MountKind::Device { .. } => match (spec.pending_mode, spec.mode) {
             (Some(MountMode::OnDemand), _) => parts.push(gettext("Going online only")),
             (Some(MountMode::Mirror), _) => parts.push(gettext("Switching to synced")),
@@ -1655,17 +1730,25 @@ pub(crate) fn location_subtitle(spec: &MountSpec) -> String {
             (Some(MountMode::Unknown) | None, _) => parts.push(folder_mode_label(false)),
         },
     }
-    if matches!(spec.kind, MountKind::Device { .. }) {
+    if matches!(
+        spec.kind,
+        MountKind::Device { .. } | MountKind::Attached { .. }
+    ) {
         parts.push(match &spec.progress {
             Some(p) => sync_progress_label(p),
             None if spec.paused => pgettext("state", "paused"),
-            None => sync_state_label(&spec.state).to_string(),
+            None => sync_state_label(
+                &spec.state,
+                spec.mode == MountMode::Mirror && spec.last_sync == 0,
+            ),
         });
     }
     // Only the locations that are supposed to have a session report its absence:
     // a mirror folder never has one.
-    let expects_session = !matches!(spec.kind, MountKind::Device { .. })
-        || spec.mode == MountMode::OnDemand
+    let expects_session = !matches!(
+        spec.kind,
+        MountKind::Device { .. } | MountKind::Attached { .. }
+    ) || spec.mode == MountMode::OnDemand
         || spec.pending_mode == Some(MountMode::OnDemand);
     if expects_session && !spec.mounted {
         // Translators: a folder's files can't be opened right now.
@@ -1696,6 +1779,18 @@ mod tests {
         }
     }
 
+    #[test]
+    fn an_attached_mirror_is_available_without_a_fuse_session() {
+        let spec = spec(
+            MountKind::Attached { sync_folder_id: 7 },
+            MountMode::Mirror,
+            false,
+        );
+        let subtitle = location_subtitle(&spec);
+        assert!(subtitle.contains("My files mirror"), "{subtitle}");
+        assert!(!subtitle.contains("not available"), "{subtitle}");
+    }
+
     #[test]
     fn a_mirror_folder_is_never_reported_as_unmounted() {
         // It is a plain local directory: no FUSE session is expected, so saying
@@ -1705,7 +1800,25 @@ mod tests {
             MountMode::Mirror,
             false,
         );
+        assert_eq!(location_subtitle(&spec), "Synced · waiting for first sync");
+    }
+
+    /// A folder whose first pass has not run is not up to date, though its
+    /// state column starts out `idle` (`docs/BUGS.md` B261).
+    #[test]
+    fn a_folder_reads_up_to_date_only_after_its_first_sync() {
+        let mut spec = spec(
+            MountKind::Device { sync_folder_id: 7 },
+            MountMode::Mirror,
+            false,
+        );
+        assert_eq!(location_subtitle(&spec), "Synced · waiting for first sync");
+        spec.last_sync = 1_700_000_000;
         assert_eq!(location_subtitle(&spec), "Synced · up to date");
+        // A folder that failed before it ever synced says so.
+        spec.last_sync = 0;
+        spec.state = "error".into();
+        assert_eq!(location_subtitle(&spec), "Synced · sync error");
     }
 
     #[test]

crates/pdfs-gui/src/app/pages/login.rs

@@ -9,6 +9,9 @@ pub(crate) struct LoginState {
     /// Spins inside the Sign in button while a sign-in is running.
     pub(crate) login_spinner: Spinner,
     pub(crate) login_status: gtk4::Label,
+    /// Shown over the form while a saved sign-in exists but the keyring would
+    /// not hand it over; see [`keyring_unreadable`].
+    pub(crate) keyring_banner: adw::Banner,
 }
 
 /// Where the login page's account links go.
@@ -87,6 +90,12 @@ pub(crate) fn build_login_page() -> (gtk4::Widget, LoginState) {
         .child(&inner)
         .build();
     let scroll = gtk4::ScrolledWindow::builder().child(&clamp).build();
+    let keyring_banner = adw::Banner::builder()
+        .title(gettext(
+            "Couldn't read your saved sign-in. Unlock the system keyring, then try again.",
+        ))
+        .button_label(gettext("Retry"))
+        .build();
 
     (
         scroll.upcast(),
@@ -96,10 +105,80 @@ pub(crate) fn build_login_page() -> (gtk4::Widget, LoginState) {
             login_button,
             login_spinner,
             login_status,
+            keyring_banner,
         },
     )
 }
 
+/// The stored session, `None` when there is none, or the keyring's error when
+/// it could not be read. A locked or absent keyring is not a sign-out: the
+/// session is still saved, and signing in again would only replace it.
+pub(crate) fn read_session() -> pdfs_core::Result<Option<auth::StoredSession>> {
+    match auth::load() {
+        Ok(session) => Ok(Some(session)),
+        Err(pdfs_core::Error::NotLoggedIn) => Ok(None),
+        Err(e) => Err(e),
+    }
+}
+
+/// How long to wait before each automatic retry of an unreadable keyring. A
+/// keyring daemon started with the session is usually up within seconds.
+const KEYRING_RETRIES: [u32; 4] = [2, 5, 10, 30];
+
+/// The keyring refused to hand over the saved session. Keep the login page up,
+/// but say why, and pick the session up as soon as the keyring answers: on its
+/// own a few times, and whenever the user presses Retry.
+pub(crate) fn keyring_unreadable(ui: &Rc<Ui>, error: &pdfs_core::Error) {
+    tracing::warn!("cannot read the saved session: {error}");
+    let banner = &ui.login.keyring_banner;
+    if banner.is_revealed() {
+        return;
+    }
+    banner.set_revealed(true);
+    let ui_retry = ui.clone();
+    let handler = banner.connect_button_clicked(move |_| retry_session(&ui_retry));
+    // Disconnected once the banner goes, so a later failure wires it afresh.
+    let handler = RefCell::new(Some(handler));
+    banner.connect_revealed_notify(move |banner| {
+        if !banner.is_revealed()
+            && let Some(handler) = handler.borrow_mut().take()
+        {
+            banner.disconnect(handler);
+        }
+    });
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        for seconds in KEYRING_RETRIES {
+            glib::timeout_future_seconds(seconds).await;
+            if !ui.login.keyring_banner.is_revealed() {
+                return;
+            }
+            retry_session(&ui);
+        }
+    });
+}
+
+/// Read the saved session again after [`keyring_unreadable`]. Found: show the
+/// signed-in window. Gone: the plain login page. Still unreadable: keep waiting.
+fn retry_session(ui: &Rc<Ui>) {
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let Ok(result) = gio::spawn_blocking(read_session).await else {
+            return;
+        };
+        match result {
+            Ok(session) => {
+                ui.login.keyring_banner.set_revealed(false);
+                if session.is_some() && ui.session.borrow().is_none() {
+                    *ui.session.borrow_mut() = session;
+                    refresh(&ui);
+                }
+            }
+            Err(e) => tracing::debug!("the keyring still cannot be read: {e}"),
+        }
+    });
+}
+
 /// Connect the sign-in button: read the fields, run [`auth::login`] on a worker
 /// thread, and report the outcome back on the main loop.
 pub(crate) fn wire_login(ui: &Rc<Ui>) {
@@ -199,7 +278,14 @@ pub(crate) fn wire_login(ui: &Rc<Ui>) {
                     ui.login.login_status.set_text("");
                     ui.login.password.set_text("");
                     // Cache the new identity so `refresh` never hits the keyring.
-                    *ui.session.borrow_mut() = auth::load().ok();
+                    // Read on a worker: a keyring that has to be unlocked first
+                    // answers only once the user has, and the window must not
+                    // freeze until then.
+                    match gio::spawn_blocking(read_session).await {
+                        Ok(Ok(session)) => *ui.session.borrow_mut() = session,
+                        Ok(Err(e)) => keyring_unreadable(&ui, &e),
+                        Err(_) => {}
+                    }
                     // Enable+start the mount service now that we have a session.
                     let _ = gio::spawn_blocking(service::enable_start).await;
                     refresh(&ui);
@@ -227,6 +313,11 @@ pub(crate) fn login_error_message(error: &pdfs_core::Error) -> String {
         pdfs_core::Error::Proton(ProtonError::Api(api)) if api.http_status == 429 => {
             gettext("Too many sign-in attempts. Wait a few minutes and try again.")
         }
+        // Proton's text for this one asks the user to update an app that is
+        // already current.
+        pdfs_core::Error::Proton(e) if pdfs_core::error::sign_in_blocked(e) => gettext(
+            "Proton is temporarily refusing sign-in from this device. Your app version is not the problem. Wait several hours, up to a day, without trying again, then sign in.",
+        ),
         pdfs_core::Error::Proton(ProtonError::Api(api)) if !api.message.is_empty() => {
             api.message.clone()
         }
@@ -597,7 +688,7 @@ pub(crate) fn sign_out(ui: &Rc<Ui>) {
             glib::spawn_future_local(async move {
                 let result = gio::spawn_blocking(|| {
                     service::disable_stop();
-                    auth::logout().map_err(|e| e.to_string())
+                    auth::logout().map(|_| ()).map_err(|e| e.to_string())
                 })
                 .await;
                 if let Ok(Err(e)) = result {
@@ -628,6 +719,21 @@ mod tests {
         assert!(login_error_message(&error).contains("no mailbox password"));
     }
 
+    #[test]
+    fn a_blocked_sign_in_does_not_ask_for_an_update() {
+        use pdfs_core::proton_sdk::api::ResponseCode;
+        use pdfs_core::proton_sdk::{ProtonApiError, ProtonError};
+        let error = pdfs_core::Error::Proton(ProtonError::Api(ProtonApiError {
+            code: ResponseCode::Blocked,
+            http_status: 422,
+            message: "This version of the app is no longer supported, please update to continue using the app".into(),
+            details: None,
+        }));
+        let message = login_error_message(&error);
+        assert!(message.contains("temporarily refusing"), "{message}");
+        assert!(!message.contains("update"), "{message}");
+    }
+
     #[test]
     fn an_unmapped_error_keeps_its_text() {
         let error = pdfs_core::Error::Other("something odd".into());

crates/pdfs-gui/src/app/pages/places.rs

@@ -267,7 +267,12 @@ fn want_map_thumb(ui: &Rc<Ui>, photo: &PhotoItem) {
     }
     // A town's card may be waiting for the same photo: share its picture
     // rather than take its place in the queue.
-    let waiting = ui.gallery.thumb_wanted.borrow().get(&photo.uid).cloned();
+    let waiting = ui
+        .gallery
+        .thumb_wanted
+        .borrow()
+        .get(&photo.uid)
+        .and_then(|waiting| waiting.first().cloned());
     let picture = waiting.unwrap_or_else(|| {
         let picture = gtk4::Picture::new();
         want_thumb(ui, photo, &picture);
@@ -362,7 +367,12 @@ fn show_spot_photos(ui: &Rc<Ui>, photos: Vec<(PlaceInfo, PhotoItem)>, (x, y): (f
 /// Show photo's thumbnail in `picture`, sharing one another widget is
 /// already waiting for.
 fn spot_thumb(ui: &Rc<Ui>, photo: &PhotoItem, picture: &gtk4::Picture) {
-    let waiting = ui.gallery.thumb_wanted.borrow().get(&photo.uid).cloned();
+    let waiting = ui
+        .gallery
+        .thumb_wanted
+        .borrow()
+        .get(&photo.uid)
+        .and_then(|waiting| waiting.first().cloned());
     match waiting {
         Some(waiting) => {
             waiting
@@ -392,21 +402,45 @@ fn load_place_locations(ui: &Rc<Ui>, id: u32) {
     });
 }
 
-/// Open `place` and then photo `uid` in it, paging through the town until
-/// the photo has loaded.
+/// Open photo `uid` of `place` from the map or a spot's list, paging through
+/// the town until the photo has loaded.
+///
+/// The lightbox steps through the gallery's model, so the town is opened
+/// behind it. Closing the lightbox goes back to the map rather than leaving
+/// the user in a town timeline they never asked for.
 fn open_place_photo(ui: &Rc<Ui>, place: PlaceInfo, uid: String) {
+    let id = place.id;
     open_place(ui, place);
-    view_when_loaded(ui, uid);
+    view_when_loaded(ui, id, uid);
 }
 
-fn view_when_loaded(ui: &Rc<Ui>, uid: String) {
+/// The open place's id, if a place is open.
+fn open_place_id(ui: &Ui) -> Option<u32> {
+    ui.gallery.place.borrow().as_ref().map(|place| place.id)
+}
+
+fn view_when_loaded(ui: &Rc<Ui>, id: u32, uid: String) {
     let ui_page = ui.clone();
     ui.gallery.page_waiters.borrow_mut().push(Box::new(move || {
         let ui = ui_page;
+        // The user went elsewhere while the town loaded: whatever page lands
+        // now belongs to that, and must not pop the lightbox up over it.
+        if open_place_id(&ui) != Some(id) {
+            return;
+        }
         if find_photo_index(&ui.gallery.model, &uid).is_some() {
-            open_photo_viewer(&ui, uid);
-        } else if ui.gallery.has_more.get() && ui.gallery.place.borrow().is_some() {
-            view_when_loaded(&ui, uid);
+            let window = open_photo_viewer(&ui, uid);
+            let ui_close = ui.clone();
+            window.connect_close_request(move |_| {
+                // Only if the town is still what the lightbox was showing: "Show
+                // on map" in the lightbox has already moved on by itself.
+                if open_place_id(&ui_close) == Some(id) {
+                    show_place_grid(&ui_close);
+                }
+                glib::Propagation::Proceed
+            });
+        } else if ui.gallery.has_more.get() {
+            view_when_loaded(&ui, id, uid);
             ui.gallery.burst.set(true);
             load_gallery(&ui, true);
         }
@@ -422,9 +456,7 @@ fn open_place(ui: &Rc<Ui>, place: PlaceInfo) {
 
     // As in an album: no filters, no Upload, no view switch — back leads out.
     ui.gallery.filters.set_visible(false);
-    ui.gallery.view_switch.widget().set_visible(false);
-    ui.gallery.upload.set_visible(false);
-    ui.gallery.back.set_visible(true);
+    sync_header(ui);
     ui.gallery.kind.set(None);
     ui.gallery.range.set(None);
 
@@ -439,16 +471,16 @@ pub(crate) fn close_place(ui: &Rc<Ui>) {
         return;
     }
     ui.gallery.title.set_title(&gettext("Photos"));
-    ui.gallery.view_switch.widget().set_visible(true);
-    ui.gallery.upload.set_visible(true);
-    ui.gallery.back.set_visible(false);
+    sync_header(ui);
 }
 
 /// Show the place grid's own status page (loading, empty, or an error).
 fn places_status(ui: &Rc<Ui>, icon: &str, title: &str, description: &str) {
     ui.gallery.places_status.set_icon_name(Some(icon));
     ui.gallery.places_status.set_title(title);
-    ui.gallery.places_status.set_description(Some(description));
+    ui.gallery
+        .places_status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.gallery.places_stack.set_visible_child_name("status");
 }
 

crates/pdfs-gui/src/app/pages/shared.rs

@@ -279,10 +279,7 @@ pub(crate) fn wire_shared(ui: &Rc<Ui>, widgets: &SharedWidgets) {
         }));
 
     let ui_back = ui.clone();
-    widgets.back.connect_clicked(move |_| {
-        ui_back.shared.nav.borrow_mut().pop();
-        load_shared(&ui_back);
-    });
+    widgets.back.connect_clicked(move |_| shared_back(&ui_back));
     let ui_retry = ui.clone();
     widgets
         .retry
@@ -311,11 +308,21 @@ pub(crate) fn wire_shared(ui: &Rc<Ui>, widgets: &SharedWidgets) {
 pub(crate) fn shared_status(ui: &Rc<Ui>, icon: &str, title: &str, description: &str, retry: bool) {
     ui.shared.status.set_icon_name(Some(icon));
     ui.shared.status.set_title(title);
-    ui.shared.status.set_description(Some(description));
+    ui.shared
+        .status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.shared.retry.set_visible(retry);
     ui.shared.content.set_visible_child_name("status");
 }
 
+/// Back out of a shared folder to the level above: the page's Back button, and
+/// Alt+Left or Backspace. A no-op at the top.
+pub(crate) fn shared_back(ui: &Rc<Ui>) {
+    if ui.shared.nav.borrow_mut().pop().is_some() {
+        load_shared(ui);
+    }
+}
+
 /// Fetch the top level (shared-with-me, invitations, saved links) in parallel
 /// and repaint the page once all three land.
 ///
@@ -441,6 +448,7 @@ fn repaint_shared_files(ui: &Rc<Ui>, entries: &[DirEntry]) {
     let nav = ui.shared.nav.borrow().clone();
     repaint_shared_crumb(ui, &nav);
     let top = nav.is_empty();
+    let another_folder = ui.shared.listed.borrow().as_ref() != Some(&nav);
     *ui.shared.listed.borrow_mut() = Some(nav);
     if entries.is_empty() {
         ui.shared.files.model.remove_all();
@@ -465,8 +473,11 @@ fn repaint_shared_files(ui: &Rc<Ui>, entries: &[DirEntry]) {
     }
     ui.shared.files_content.set_visible_child_name("list");
     // Only the rows that changed are swapped, so a refresh keeps the selection
-    // and the scroll position.
+    // and the scroll position. Another folder starts from its first entry.
     replace_items(&ui.shared.files.model, entries);
+    if another_folder {
+        ui.shared.files.scroll_to_top();
+    }
 }
 
 /// Rebuild the breadcrumb trail for `nav`: "Shared with me", then each folder
@@ -818,6 +829,7 @@ fn invitation_row(inv: &InvitationInfo) -> adw::ActionRow {
         .title(&item)
         // Translators: {email} is the address of the person who sent the invitation.
         .subtitle(gettext_f("From {email}", &[("email", &inv.inviter_email)]))
+        .use_markup(false)
         .build();
     row.add_prefix(&gtk4::Image::from_icon_name(if inv.is_dir {
         "folder-symbolic"
@@ -862,6 +874,7 @@ fn repaint_links(ui: &Rc<Ui>, bookmarks: &[BookmarkInfo]) {
         let row = adw::ActionRow::builder()
             .title(&title)
             .subtitle(&bm.url)
+            .use_markup(false)
             .subtitle_lines(1)
             .activatable(true)
             .tooltip_text(gettext("Open in browser"))

crates/pdfs-gui/src/app/pages/shared_by_me.rs

@@ -329,7 +329,9 @@ pub(crate) fn shared_by_me_status(
 ) {
     ui.shared_by_me.status.set_icon_name(Some(icon));
     ui.shared_by_me.status.set_title(title);
-    ui.shared_by_me.status.set_description(Some(description));
+    ui.shared_by_me
+        .status
+        .set_description(Some(&gtk4::glib::markup_escape_text(description)));
     ui.shared_by_me.retry.set_visible(retry);
     ui.shared_by_me.content.set_visible_child_name("status");
     ui.shared_by_me.subtitle.set_subtitle("");
@@ -622,6 +624,7 @@ pub(crate) fn shared_item_as_entry(item: &SharedItem) -> DirEntry {
         size: 0,
         modified: item.modified,
         pinned: false,
+        pinned_by_folder: false,
         cached: false,
         uid: item.uid.clone(),
         path: item.path.clone(),