fix(fuse): fill an incomplete queued revision's gaps on a write open

A partial write whose base was not in the content cache queued an
incomplete revision, and every write open over it was refused with EIO
until the drain uploaded it. CI's one-client-lan simulation hit this on
seed 1: a create over a file whose partial edit had not drained yet.

The write open now copies the blob and fills its gaps from the remote
base with Core::fill_gaps, as the drain does, and fails only when that
fill fails (B204).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EuyxByBpK3fSWtyPkugeHz

.github/workflows/aur.yml

@@ -67,7 +67,13 @@ jobs:
             User aur
           EOF
           # Pin the host key to the fingerprint published on aur.archlinux.org.
-          ssh-keyscan -t ed25519 aur.archlinux.org > "$HOME/.ssh/known_hosts"
+          # The scan sometimes returns nothing from the runner, so retry it.
+          for attempt in 1 2 3 4 5; do
+            ssh-keyscan -T 15 -t ed25519 aur.archlinux.org > "$HOME/.ssh/known_hosts" &&
+              [ -s "$HOME/.ssh/known_hosts" ] && break
+            echo "ssh-keyscan attempt $attempt returned no key; retrying"
+            sleep 10
+          done
           ssh-keygen -lf "$HOME/.ssh/known_hosts" | grep -q 'SHA256:RFzBCUItH9LZS0cKB5UE6ceAYhBD5C8GeOBip8Z11+4'
           chown -R builder: "$HOME/.ssh"
           chmod 600 "$HOME/.ssh/aur"

.github/workflows/ci.yml

@@ -64,6 +64,53 @@ jobs:
   # Real Proton credentials and /dev/fuse deliberately do not run on pull
   # requests. Follow docs/TESTING.md on a dedicated test-account runner.
 
+  # The seeded simulation runs (docs/TESTING.md): real FUSE
+  # daemons against an in-memory Drive, so they need /dev/fuse but no account.
+  simulation:
+    if: github.event_name != 'pull_request'
+    runs-on: ubuntu-24.04
+    timeout-minutes: 30
+
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Install native dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            pkg-config \
+            fuse3 \
+            libfuse3-dev \
+            libgtk-4-dev \
+            libadwaita-1-dev \
+            libwebkitgtk-6.0-dev \
+            libsecret-1-dev \
+            libdbus-1-dev
+
+      - name: Install minimum supported Rust
+        uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: '1.96'
+          cache: false
+
+      - uses: swatinem/rust-cache@v2
+        with:
+          shared-key: debug
+          save-if: false
+
+      - name: Simulation runs
+        run: 'cargo test -p pdfs-fuse --lib --locked sim:: -- --ignored --test-threads=1'
+
+      # A hung step writes every daemon thread's stack next to the run's
+      # state; without them a hang that does not replay cannot be told apart.
+      - name: Keep the stacks of a hung run
+        if: failure()
+        uses: actions/upload-artifact@v7
+        with:
+          name: simulation-stacks
+          path: /tmp/pdfs-sim-*/stacks.txt
+          if-no-files-found: ignore
+
   # Keeps the release-profile dependencies cached on main, where the release
   # workflow can restore them; a tag cannot reuse the caches of earlier tags.
   release-cache:

.github/workflows/test-build.yml

@@ -0,0 +1,121 @@
+name: Test build
+
+# On-demand Fedora RPM of any branch, for someone to try a fix before it ships.
+# Run it from the Actions tab ("Run workflow", pick the branch). Built inside a
+# Fedora container so the binaries link against Fedora's own GTK, libadwaita and
+# WebKitGTK, not the Ubuntu ones the release RPM is built against.
+#
+# The RPM is unsigned and versioned `<Cargo version>-1.test.<sha>`, so it sorts
+# below the release it precedes and `dnf` replaces it when that ships.
+on:
+  workflow_dispatch:
+    inputs:
+      fedora:
+        description: 'Fedora release to build on'
+        required: false
+        default: '44'
+        type: string
+      prerelease:
+        description: 'Also publish a pre-release anyone can download without a GitHub login'
+        required: false
+        default: false
+        type: boolean
+
+permissions:
+  contents: read
+
+concurrency:
+  group: test-build-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  rpm:
+    name: Fedora ${{ inputs.fedora }} RPM
+    runs-on: ubuntu-24.04
+    container: fedora:${{ inputs.fedora }}
+    steps:
+      - name: Install build dependencies
+        run: |
+          dnf install -y --setopt=install_weak_deps=False \
+            git rpm-build gcc gcc-c++ make gettext curl \
+            pkgconf-pkg-config fuse3-devel gtk4-devel libadwaita-devel \
+            libsecret-devel dbus-devel glib2-devel webkitgtk6.0-devel
+
+      - name: Checkout repository
+        uses: actions/checkout@v7
+
+      # Fedora's packaged Rust can trail the workspace's minimum (1.96).
+      - name: Set up Rust
+        uses: actions-rust-lang/setup-rust-toolchain@v1
+        with:
+          toolchain: '1.96'
+          cache: false
+
+      - name: Cache Cargo target
+        uses: swatinem/rust-cache@v2
+        with:
+          shared-key: fedora-test-build
+          save-if: false
+
+      - name: Build release binaries
+        run: cargo build --release --locked
+
+      - name: Package RPM
+        run: |
+          git config --global --add safe.directory "$GITHUB_WORKSPACE"
+          VERSION=$(grep -m1 '^version' Cargo.toml | cut -d'"' -f2)
+          SHORT=${GITHUB_SHA::7}
+          mkdir -p rpmbuild/{BUILD,RPMS,SOURCES,SPECS,SRPMS,BUILDROOT,db}
+          rpmbuild -bb \
+            --nodeps \
+            --define "_topdir $PWD/rpmbuild" \
+            --define "_sourcedir $PWD" \
+            --define "git_dir $PWD" \
+            --define "prebuilt 1" \
+            --define "version ${VERSION}" \
+            --define "dist .test.${SHORT}" \
+            --define "_dbpath $PWD/rpmbuild/db" \
+            packaging/proton-drive-linux.spec
+          mkdir -p out
+          cp rpmbuild/RPMS/x86_64/*.rpm out/
+          # The bare binaries, for trying one without installing anything.
+          tar -czf "out/proton-drive-linux-${VERSION}-${SHORT}-fedora${{ inputs.fedora }}-x86_64.tar.gz" \
+            -C target/release pdfs pdfs-tray pdfs-app pdfs-prompt
+          ls -l out
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v7
+        with:
+          name: proton-drive-linux-fedora${{ inputs.fedora }}-${{ github.sha }}
+          path: out/*
+          retention-days: 14
+          if-no-files-found: error
+
+  prerelease:
+    name: Publish pre-release
+    needs: rpm
+    if: inputs.prerelease
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: write
+    steps:
+      - name: Download build
+        uses: actions/download-artifact@v8
+        with:
+          path: out
+          merge-multiple: true
+
+      # One rolling pre-release per branch: a new run replaces the last one, so
+      # the link a tester was given keeps pointing at the newest build.
+      - name: Publish
+        env:
+          GH_TOKEN: ${{ github.token }}
+          GH_REPO: ${{ github.repository }}
+        run: |
+          TAG="test-$(echo "${GITHUB_REF_NAME}" | tr -c 'A-Za-z0-9._\n' '-')"
+          gh release delete "$TAG" --cleanup-tag --yes 2>/dev/null || true
+          gh release create "$TAG" out/* \
+            --target "$GITHUB_SHA" \
+            --prerelease \
+            --title "Test build of ${GITHUB_REF_NAME} (${GITHUB_SHA::7})" \
+            --notes "Unsigned test build of branch \`${GITHUB_REF_NAME}\` at ${GITHUB_SHA}. Not a release; replaced by the next test build of this branch."

CONTRIBUTING.md

@@ -39,9 +39,9 @@ cargo test --workspace --locked
 scripts/fuse-acceptance.sh --offline-only
 ```
 
-Changes to the FUSE layer, sync, or the pending-operation queue should also be exercised against a
+Changes to the FUSE layer, sync, or the queue should also pass the simulation runs and be
-real mount before review — see [`docs/TESTING.md`](docs/TESTING.md). Live runs are destructive:
+exercised against a real mount before review — see [`docs/TESTING.md`](docs/TESTING.md). Live
-use a dedicated test account, never one holding data you cannot lose.
+runs are destructive: use a dedicated test account, never one holding data you cannot lose.
 
 ## Making changes
 

Cargo.lock

@@ -3474,7 +3474,7 @@ checksum = "2ee67f1008b1ba2321834326597b8e186293b049a023cdef258527550b9935b4"
 
 [[package]]
 name = "pdfs-cli"
-version = "2.8.2"
+version = "3.2.0"
 dependencies = [
  "anyhow",
  "clap",
@@ -3485,13 +3485,15 @@ dependencies = [
  "tokio",
  "tracing",
  "tracing-subscriber",
+ "zeroize",
 ]
 
 [[package]]
 name = "pdfs-core"
-version = "2.8.2"
+version = "3.2.0"
 dependencies = [
  "async-trait",
+ "base64 0.23.1",
  "dbus-secret-service-keyring-store",
  "directories",
  "ignore",
@@ -3508,13 +3510,15 @@ dependencies = [
  "thiserror 2.0.20",
  "tokio",
  "tracing",
+ "zeroize",
  "zip",
 ]
 
 [[package]]
 name = "pdfs-fuse"
-version = "2.8.2"
+version = "3.2.0"
 dependencies = [
+ "async-trait",
  "base64 0.23.1",
  "fuser",
  "futures",
@@ -3528,12 +3532,13 @@ dependencies = [
  "sha1 0.11.0",
  "tokio",
  "tracing",
+ "tracing-subscriber",
  "zip",
 ]
 
 [[package]]
 name = "pdfs-gui"
-version = "2.8.2"
+version = "3.2.0"
 dependencies = [
  "anyhow",
  "async-channel",
@@ -3570,9 +3575,9 @@ checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
 [[package]]
 name = "pgp"
-version = "0.20.0"
+version = "0.21.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cfa4743b28656065ff4c0ba09e46b357a65e8c00fc2341e89084b82f87cbdf1"
+checksum = "ae70f4d9325a391db30d115d6191a7bb67cec856aa0bba131290f0c4e09a532a"
 dependencies = [
  "aead 0.5.2",
  "aes 0.8.4",
@@ -3773,9 +3778,9 @@ dependencies = [
 
 [[package]]
 name = "proton-drive-rs"
-version = "0.7.2"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d6ce113d234474821d34787436ee80e1458e3d8a8f97212219615ed315eb70be"
+checksum = "1e789cab811c5e73e47fd97810b78a513cb254f4dd763b4eb3cad680d6dd31da"
 dependencies = [
  "async-trait",
  "base64 0.23.1",
@@ -3800,9 +3805,9 @@ dependencies = [
 
 [[package]]
 name = "proton-sdk"
-version = "0.7.2"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2a33c67df9694f90ce60e5b34984275956244138511b4640ca0d100e1dac8b3d"
+checksum = "ace260acbf88c26f5bd4aef8c8c9898c322163c56620bdef3b6dd7742bec7619"
 dependencies = [
  "aes-gcm 0.11.1",
  "async-trait",
@@ -3829,6 +3834,7 @@ dependencies = [
  "thiserror 2.0.20",
  "tokio",
  "tracing",
+ "zeroize",
 ]
 
 [[package]]

Cargo.toml

@@ -3,7 +3,7 @@ resolver = "2"
 members = ["crates/pdfs-core", "crates/pdfs-fuse", "crates/pdfs-cli", "crates/pdfs-gui"]
 
 [workspace.package]
-version = "2.8.2"
+version = "3.2.0"
 edition = "2024"
 license = "MIT"
 authors = ["Nils Pukropp <contact@narl.io>"]
@@ -15,8 +15,8 @@ keywords = ["proton", "drive", "fuse", "sync", "linux"]
 categories = ["filesystem", "command-line-utilities"]
 
 [workspace.dependencies]
-proton-sdk = { version = "0.7.2" }
+proton-sdk = { version = "0.8.2" }
-proton-drive-rs = { version = "0.7.2" }
+proton-drive-rs = { version = "0.8.2" }
 
 # Internal crates.
 pdfs-core = { path = "crates/pdfs-core" }
@@ -26,6 +26,7 @@ tokio = { version = "1", features = ["rt-multi-thread", "macros", "sync", "fs",
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 base64 = "0.23"
+zeroize = "1"
 thiserror = "2"
 anyhow = "1"
 # Non-poisoning mutexes. A handler that panics while holding a lock must not

README.md

@@ -15,6 +15,7 @@ scriptable CLI.
 [![AUR](https://img.shields.io/aur/version/proton-drive-for-linux)](https://aur.archlinux.org/packages/proton-drive-for-linux)
 [![License: MIT](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)
 [![Rust 1.96+](https://img.shields.io/badge/rust-1.96%2B-orange.svg)](https://www.rust-lang.org)
+[![Buy me a coffee](https://img.shields.io/badge/Buy%20me%20a%20coffee-FFDD00?logo=buymeacoffee&logoColor=black)](https://buymeacoffee.com/narl)
 
 <img src="images/files.png" alt="My files in the Proton Drive app" width="820">
 
@@ -38,8 +39,9 @@ scriptable CLI.
 - **Synced folders.** Back up folders such as `~/Documents` under your computer in Proton Drive,
   as a full two-way copy or online only. Gitignore-style `.pdfsignore` rules, conflict copies
   instead of overwrites, pause and bandwidth limits.
-- **Safe writes.** Changes are staged on disk and queued before they are acknowledged, so they
+- **Works at local speed.** Making, renaming and deleting files and folders returns at once, online
-  survive a lost connection, a crash or a reboot and upload when they can.
+  or offline. Changes are staged on disk and queued before they are acknowledged, so they survive
+  a lost connection, a crash or a reboot and reach Drive when they can.
 
 **Desktop app**
 
@@ -50,7 +52,8 @@ scriptable CLI.
 - **Sharing.** Invite people as viewer, editor or admin, create public links with password and
   expiry, accept invitations.
 - **Sync overview.** What is uploading, what is waiting, what failed and why, and a history of
-  what happened.
+  what happened. A change Drive refuses (storage full, access taken away) shows at once, on the
+  file too, and can be exported or discarded.
 - **Tray icon** with status, pause and quick actions, and a **search launcher** (`pdfs-prompt`)
   that searches Proton Drive and your home folder together, as its own window, through fuzzel,
   rofi or wofi, or live in `fzf`.
@@ -146,7 +149,7 @@ 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#8-threat-model-what-this-client-writes-to-disk-in-plaintext).
+[threat model](docs/ARCHITECTURE.md#10-threat-model-what-this-client-writes-to-disk-in-plaintext).
 
 ## Contributing
 
@@ -154,6 +157,13 @@ Bug reports, translations and patches are welcome. See [CONTRIBUTING.md](CONTRIB
 workflow and the checks CI runs, and [SECURITY.md](SECURITY.md) to report a vulnerability
 privately.
 
+## Support
+
+Proton Drive Linux is free and built in spare time. If it saves you a few headaches, you can
+[buy me a coffee](https://buymeacoffee.com/narl).
+
+<a href="https://buymeacoffee.com/narl"><img src="https://img.shields.io/badge/Buy%20me%20a%20coffee-FFDD00?logo=buymeacoffee&logoColor=black" alt="Buy me a coffee"></a>
+
 ## License
 
 Released under the [MIT License](LICENSE).

SECURITY.md

@@ -31,7 +31,7 @@ the interesting boundaries are:
   or the wrong key material to Proton.
 
 What the client deliberately keeps in plaintext on disk, and why, is documented in the
-[threat model](docs/ARCHITECTURE.md#8-threat-model-what-this-client-writes-to-disk-in-plaintext).
+[threat model](docs/ARCHITECTURE.md#10-threat-model-what-this-client-writes-to-disk-in-plaintext).
 Behaviour described there is known and not a vulnerability by itself; a way to make it worse
 than described is.
 

crates/pdfs-cli/Cargo.toml

@@ -23,3 +23,4 @@ tracing-subscriber.workspace = true
 clap.workspace = true
 rpassword.workspace = true
 serde_json.workspace = true
+zeroize.workspace = true

crates/pdfs-cli/src/main.rs

@@ -14,12 +14,45 @@ use pdfs_core::cache::ContentCache;
 use pdfs_core::config::AppDirs;
 use pdfs_core::control::{
     ConflictKeep, ErrorKind, MountKind, RefreshScope, Request as CtlRequest,
-    Response as CtlResponse, RestoreItem as CtlRestoreItem, ShareEntryKind, SyncPhase,
+    Response as CtlResponse, RestoreItem as CtlRestoreItem, ShareEntryKind, SyncIssue, SyncPhase,
     pending_summary,
 };
 use pdfs_core::db::Db;
 use pdfs_core::service;
 
+/// `println!` for this binary, shadowing std's, which panics when stdout is
+/// closed: `pdfs ls | head` ended in a "Broken pipe" panic once `head` had its
+/// lines. This one hands the failure to [`stdout_written`] instead.
+///
+/// Restoring the default `SIGPIPE` would also stop the panic, but the same
+/// binary runs the daemon, which must not die when a socket's peer goes away.
+macro_rules! println {
+    ($($arg:tt)*) => {{
+        use std::io::Write as _;
+        $crate::stdout_written(writeln!(std::io::stdout(), $($arg)*))
+    }};
+}
+
+/// [`println!`] without the newline.
+macro_rules! print {
+    ($($arg:tt)*) => {{
+        use std::io::Write as _;
+        $crate::stdout_written(write!(std::io::stdout(), $($arg)*))
+    }};
+}
+
+/// Exit on a failed write to stdout. A closed pipe means the reader has all it
+/// wanted, so that exit is a success.
+fn stdout_written(result: std::io::Result<()>) {
+    if let Err(error) = result {
+        if error.kind() == std::io::ErrorKind::BrokenPipe {
+            std::process::exit(0);
+        }
+        eprintln!("Error: writing to stdout: {error}");
+        std::process::exit(1);
+    }
+}
+
 #[derive(Parser)]
 #[command(
     name = "pdfs",
@@ -102,6 +135,24 @@ enum Command {
         /// Account email; prompted if omitted.
         #[arg(short, long)]
         username: Option<String>,
+        /// For a two-password account, keep the mailbox password's unlock in the
+        /// system keyring so the daemon starts without asking after every login.
+        /// Without it the unlock lives in kernel memory for this session only.
+        #[arg(long)]
+        remember: bool,
+    },
+    /// Enter the mailbox password of a two-password account so the daemon can
+    /// unlock your files. Needed once per login session.
+    Unlock {
+        /// Keep the unlock in the system keyring instead of kernel memory only.
+        #[arg(long)]
+        remember: bool,
+    },
+    /// Forget the unlock held in kernel memory; the account is locked again.
+    Lock {
+        /// Also remove an unlock kept in the keyring with `--remember`.
+        #[arg(long)]
+        forget: bool,
     },
     /// Forget the stored session.
     Logout,
@@ -285,7 +336,8 @@ enum Command {
     },
     /// Rename a file or folder via the running daemon.
     Rename {
-        /// File/folder path, inside the mountpoint or relative to it.
+        /// File/folder path, inside My files or an on-demand synced folder, or
+        /// relative to the mountpoint.
         path: PathBuf,
         /// New name (a single path component).
         new_name: String,
@@ -304,12 +356,14 @@ enum Command {
     },
     /// Trash a file or folder via the running daemon.
     Rm {
-        /// File/folder path, inside the mountpoint or relative to it.
+        /// File/folder path, inside My files or an on-demand synced folder, or
+        /// relative to the mountpoint.
         path: PathBuf,
     },
     /// Create a folder via the running daemon.
     Mkdir {
-        /// Parent folder path, inside the mountpoint or relative to it.
+        /// Parent folder path, inside My files or an on-demand synced folder,
+        /// or relative to the mountpoint.
         parent: PathBuf,
         /// New folder name (a single path component).
         name: String,
@@ -574,6 +628,15 @@ enum DeviceCmd {
         #[arg(long, conflicts_with = "uid")]
         clear: bool,
     },
+    /// Move another computer's folders into this computer's backup and sync
+    /// them here. The other computer stays registered, without those folders.
+    Migrate {
+        /// Device uid (from `devices list`).
+        uid: String,
+        /// Skip the confirmation and accept every proposed local path.
+        #[arg(long)]
+        yes: bool,
+    },
 }
 
 #[derive(Subcommand)]
@@ -641,6 +704,25 @@ enum SyncCmd {
     },
     /// List uploads and changes not yet on Proton Drive.
     Queue,
+    /// List queued changes Proton Drive refused or that keep failing, and what to do.
+    Issues,
+    /// Save the content of a queued upload (by id from `sync queue`) to a file.
+    Export {
+        /// Queue id.
+        id: i64,
+        /// Where to save it: a new file, or an existing folder to save it in.
+        dest: PathBuf,
+    },
+    /// Drop a queued change (by id from `sync queue`) and undo it here: a new file
+    /// or folder goes, anything else goes back to what Proton Drive has. Its
+    /// content is lost unless saved with `sync export` first.
+    Discard {
+        /// Queue id.
+        id: i64,
+        /// Do not ask first.
+        #[arg(long)]
+        yes: bool,
+    },
     /// Retry a queued operation now (by id from `sync queue`), or every failed one.
     Retry {
         /// Queue id; omit to retry every failed operation.
@@ -748,7 +830,9 @@ fn main() -> Result<()> {
     let cli = Cli::parse();
     JSON_OUTPUT.store(cli.json, std::sync::atomic::Ordering::Relaxed);
     match cli.command {
-        Command::Login { username } => cmd_login(username),
+        Command::Login { username, remember } => cmd_login(username, remember),
+        Command::Unlock { remember } => cmd_unlock(remember),
+        Command::Lock { forget } => cmd_lock(forget),
         Command::Logout => cmd_logout(),
         Command::Status => cmd_status(),
         Command::Locations => cmd_locations(),
@@ -892,6 +976,24 @@ fn cmd_devices(action: DeviceCmd) -> Result<()> {
             let uid = if clear { None } else { uid };
             ok_or_bail(control_request(CtlRequest::AdoptDevice { uid })?)?
         }
+        DeviceCmd::Migrate { uid, yes } => {
+            if !yes {
+                println!(
+                    "Every folder that device backs up moves into this computer's backup.\n\
+                     The device stays registered, without those folders. Stop Proton Drive\n\
+                     on that computer first, or it sees its folders disappear."
+                );
+                confirm("Move them here?")?;
+            }
+            let response = control_request(CtlRequest::MigrateDevice { uid })?;
+            // A script gets the one reply and runs `sync restore` itself.
+            if emit_json(&response)? {
+                return Ok(());
+            }
+            ok_or_bail(response)?;
+            // The folders are this device's now, so the plain restore offers them.
+            cmd_sync_restore(yes, None)?
+        }
     }
     Ok(())
 }
@@ -992,7 +1094,17 @@ fn cmd_sync(action: SyncCmd) -> Result<()> {
             })?)?
         }
         SyncCmd::Queue => return cmd_sync_queue(),
+        SyncCmd::Issues => return cmd_sync_issues(),
+        SyncCmd::Export { id, dest } => return cmd_sync_export(id, &dest),
         SyncCmd::Limit { up, down } => return cmd_sync_limit(up, down),
+        SyncCmd::Discard { id, yes } => {
+            if !yes {
+                confirm(&format!(
+                    "Discard queued change {id} and undo it here? Content not exported is lost."
+                ))?;
+            }
+            ok_or_bail(control_request(CtlRequest::DiscardPendingOp { id })?)?
+        }
         SyncCmd::Retry { id } => ok_or_bail(control_request(CtlRequest::RetryPendingOp { id })?)?,
         SyncCmd::Resume { folder: None } => {
             ok_or_bail(control_request(CtlRequest::SetSyncPaused {
@@ -1070,6 +1182,9 @@ fn cmd_sync_queue() -> Result<()> {
                     (false, _) => "due now".to_string(),
                 };
                 println!("[{}]  {}  {}  ({state})", op.id, op.kind, op.path);
+                if let Some(issue) = op.issue {
+                    println!("      needs attention: {}", issue_text(issue));
+                }
                 if let Some(error) = &op.last_error {
                     println!("      failed {} time(s): {error}", op.attempts);
                 }
@@ -1081,6 +1196,91 @@ fn cmd_sync_queue() -> Result<()> {
     Ok(())
 }
 
+/// `pdfs sync issues`: the queued changes that need the user, and what to do.
+fn cmd_sync_issues() -> Result<()> {
+    let response = control_request(CtlRequest::ListPendingOps)?;
+    let items = match response {
+        CtlResponse::PendingOps { items } => items,
+        CtlResponse::Error { message, kind } => bail!("{}", cli_error(kind, &message)),
+        other => bail!("unexpected response: {other:?}"),
+    };
+    let issues: Vec<_> = items.into_iter().filter(|op| op.failing).collect();
+    if json_enabled() {
+        println!("{}", serde_json::to_string_pretty(&issues)?);
+        return Ok(());
+    }
+    if issues.is_empty() {
+        println!("No sync issues.");
+        return Ok(());
+    }
+    for op in issues {
+        println!("[{}]  {}  {}", op.id, op.kind, op.path);
+        match op.issue {
+            Some(issue) => println!("      {}", issue_text(issue)),
+            None => println!("      keeps failing; it is retried."),
+        }
+        if let Some(error) = &op.last_error {
+            println!("      last error: {error}");
+        }
+        if op.exportable {
+            println!(
+                "      save a copy: pdfs sync export {} <file or folder>",
+                op.id
+            );
+        }
+    }
+    Ok(())
+}
+
+/// What a sync issue means, and what the user can do about it.
+fn issue_text(issue: SyncIssue) -> &'static str {
+    match issue {
+        SyncIssue::Quota => {
+            "Proton Drive storage is full. Free up space or upgrade; the change is retried."
+        }
+        SyncIssue::Access => {
+            "you can no longer change this on Proton Drive, for example because a share was \
+             revoked. Save a copy to keep the content."
+        }
+        SyncIssue::Missing => {
+            "the file or its folder is gone from Proton Drive. Save a copy to keep the content."
+        }
+        SyncIssue::Limit => {
+            "the folder holds too many items or is nested too deep. Move the file to another \
+             folder."
+        }
+        SyncIssue::Rejected => {
+            "Proton Drive rejected the change, for example the name. Rename the file."
+        }
+        SyncIssue::Unknown => "Proton Drive refused the change.",
+    }
+}
+
+/// `pdfs sync export`: save a queued upload's content. A folder as `dest`
+/// gets the file under its own name.
+fn cmd_sync_export(id: i64, dest: &Path) -> Result<()> {
+    let mut dest =
+        std::path::absolute(dest).with_context(|| format!("resolving {}", dest.display()))?;
+    if dest.is_dir() {
+        let items = match control_request(CtlRequest::ListPendingOps)? {
+            CtlResponse::PendingOps { items } => items,
+            CtlResponse::Error { message, kind } => bail!("{}", cli_error(kind, &message)),
+            other => bail!("unexpected response: {other:?}"),
+        };
+        let Some(op) = items.iter().find(|op| op.id == id) else {
+            bail!("no queued change {id}; see `pdfs sync queue`");
+        };
+        let name = Path::new(&op.path)
+            .file_name()
+            .with_context(|| format!("{} has no file name", op.path))?;
+        dest.push(name);
+    }
+    ok_or_bail(control_request(CtlRequest::ExportPendingOp {
+        id,
+        dest: dest.display().to_string(),
+    })?)
+}
+
 /// `pdfs sync restore`: list what this machine's device holds, confirm where
 /// each folder should land, then hand the mapping to the daemon.
 ///
@@ -1628,7 +1828,7 @@ fn prompt_line(label: &str) -> Result<String> {
     Ok(line.trim().to_owned())
 }
 
-fn cmd_login(username: Option<String>) -> Result<()> {
+fn cmd_login(username: Option<String>, remember: bool) -> Result<()> {
     let username = match username {
         Some(u) => u,
         None => prompt_line("Proton email")?,
@@ -1640,20 +1840,32 @@ fn cmd_login(username: Option<String>) -> Result<()> {
         prompt_line("2FA code").map_err(|e| pdfs_core::Error::Other(format!("read 2FA code: {e}")))
     };
 
+    // Only a two-password account is ever asked for this.
+    let get_mailbox = |attempt: u32| prompt_mailbox(attempt, remember);
+
+    // Proton may ask for a CAPTCHA first, usually on a VPN. The CLI has no
+    // browser engine, so the user solves the page in their own browser and says
+    // when they are done; the retry then carries the challenge token.
+    let get_hv = |hv: pdfs_core::proton_sdk::api::HumanVerification| {
+        println!(
+            "Proton is asking for a CAPTCHA before it will accept this sign-in.\n\
+             Open this page in your browser and complete it:\n\n  {}\n",
+            auth::browser_verification_url(&hv)
+        );
+        prompt_line("Press Enter once the page says you are verified")
+            .map_err(|e| pdfs_core::Error::Other(format!("read verification answer: {e}")))?;
+        Ok(auth::browser_verified(&hv))
+    };
+
     let rt = tokio::runtime::Runtime::new()?;
-    // Solving a CAPTCHA needs a browser engine, which the CLI has no business
+    rt.block_on(auth::login_interactive(
-    // carrying. Point at the app that does rather than failing with the raw API
+        &username,
-    // message, which reads as "your login is broken".
+        &password,
-    rt.block_on(auth::login(&username, &password, get_totp))
+        get_totp,
-        .map_err(|e| match e {
+        get_mailbox,
-            pdfs_core::Error::HumanVerificationRequired(_) => anyhow::anyhow!(
+        get_hv,
-                "Proton is asking for a CAPTCHA before it will accept this sign-in.\n\
+    ))
-                 Run `pdfs-app` and sign in there — it can show the verification page.\n\
+    .context("login failed")?;
-                 (This is usually triggered by a VPN or an unfamiliar IP; signing in from \
-                 your usual network often avoids it.)"
-            ),
-            other => anyhow::Error::new(other).context("login failed"),
-        })?;
 
     // A daemon that is already up is parked in `wait_for_session`, sleeping
     // between keyring checks; restart it so the mount appears now instead of
@@ -1665,9 +1877,88 @@ fn cmd_login(username: Option<String>) -> Result<()> {
     }
 
     println!("Logged in as {username}. Session stored in the system keyring.");
+    report_key_state();
     Ok(())
 }
 
+/// Ask for the mailbox password of a two-password account, without echo.
+fn prompt_mailbox(attempt: u32, remember: bool) -> pdfs_core::Result<auth::Mailbox> {
+    if attempt == 0 {
+        eprintln!("This account has a separate mailbox password.");
+    } else {
+        eprintln!("That mailbox password did not unlock the account. Try again.");
+    }
+    let password = rpassword::prompt_password("Mailbox password: ")
+        .map_err(|e| pdfs_core::Error::Other(format!("read mailbox password: {e}")))?;
+    Ok(auth::Mailbox {
+        password: zeroize::Zeroizing::new(password),
+        remember,
+    })
+}
+
+/// Say where the account's keys are held, and what that means for the next login.
+fn report_key_state() {
+    match auth::key_state() {
+        Ok(auth::KeyState::Session) => println!(
+            "Unlocked for this login session only. After you log out or reboot, run `pdfs unlock`."
+        ),
+        Ok(auth::KeyState::Locked) => println!("The account is locked. Run `pdfs unlock`."),
+        _ => {}
+    }
+}
+
+fn cmd_unlock(remember: bool) -> Result<()> {
+    auth::load().context("not logged in (run `pdfs login` first)")?;
+    let rt = tokio::runtime::Runtime::new()?;
+    // Bounded like the login prompt: three wrong answers end the command.
+    let mut attempt = 0;
+    loop {
+        let mailbox = prompt_mailbox(attempt, remember)?;
+        match rt.block_on(auth::unlock(&mailbox.password, remember)) {
+            Ok(()) => break,
+            Err(pdfs_core::Error::WrongMailboxPassword) if attempt < 2 => attempt += 1,
+            Err(e) => return Err(anyhow::Error::new(e).context("unlock failed")),
+        }
+    }
+    // A daemon parked on the locked account would otherwise notice on its next
+    // poll; restarting it makes the mount appear now, as after `pdfs login`.
+    if service::is_active() {
+        service::restart();
+    }
+    println!("Unlocked.");
+    report_key_state();
+    Ok(())
+}
+
+fn cmd_lock(forget: bool) -> Result<()> {
+    auth::lock(forget)?;
+    println!(
+        "Locked. {}",
+        if forget {
+            "Unlock removed from memory and keyring."
+        } else {
+            "Run `pdfs unlock` to unlock again."
+        }
+    );
+    // The running daemon keeps its keys until it restarts; say so, since
+    // "locked" would otherwise suggest the mount stopped.
+    if service::is_active() {
+        println!(
+            "The running daemon keeps its keys until it restarts: `systemctl --user restart proton-drive`."
+        );
+    }
+    Ok(())
+}
+
+/// `stored`, `session` or `locked`: where the account's keys are held.
+fn key_state_name() -> &'static str {
+    match auth::key_state() {
+        Ok(auth::KeyState::Stored) => "stored",
+        Ok(auth::KeyState::Session) => "session",
+        _ => "locked",
+    }
+}
+
 fn cmd_logout() -> Result<()> {
     auth::logout()?;
     println!("Stored session cleared.");
@@ -1695,6 +1986,7 @@ fn cmd_status() -> Result<()> {
             "username": session.as_ref().map(|s| s.username.clone()),
             "user_id": session.as_ref().map(|s| s.user_id.clone()),
             "scopes": session.as_ref().map(|s| s.scopes.clone()),
+            "keys": session.as_ref().map(|_| key_state_name()),
             "mount": mount,
         });
         println!("{}", serde_json::to_string_pretty(&out)?);
@@ -1705,6 +1997,11 @@ fn cmd_status() -> Result<()> {
         Ok(s) => {
             println!("Logged in as {} (user {})", s.username, s.user_id);
             println!("Scopes: {}", s.scopes.join(", "));
+            match key_state_name() {
+                "locked" => println!("Keys: locked — run `pdfs unlock`"),
+                "session" => println!("Keys: unlocked for this login session"),
+                _ => {}
+            }
         }
         Err(pdfs_core::Error::NotLoggedIn) => {
             println!("Not logged in. Run `pdfs login`.");
@@ -1727,9 +2024,12 @@ fn cmd_status() -> Result<()> {
             staged_oldest_secs,
             paused,
             paused_until,
+            session_expired,
+            tokens_unsaved,
             ..
         }) => {
             let state = match (online, paused) {
+                _ if session_expired => ", session expired: run `pdfs login`",
                 (_, true) => ", sync paused",
                 (false, false) => ", offline",
                 (true, false) => "",
@@ -1762,6 +2062,11 @@ fn cmd_status() -> Result<()> {
                     failing_error.as_deref().unwrap_or("no error recorded"),
                 );
             }
+            if tokens_unsaved {
+                println!(
+                    "Keyring    refuses the refreshed sign-in; unlock it, or a reboot needs `pdfs login`"
+                );
+            }
         }
         Ok(other) => println!("Mount: unexpected response {other:?}"),
         Err(_) => println!("Mount: not running."),
@@ -1836,7 +2141,7 @@ fn login_poll_delay(attempts: u32) -> std::time::Duration {
     std::time::Duration::from_secs(BASE_SECS.saturating_mul(factor).min(MAX_SECS))
 }
 
-/// Block until a session is stored, backing off between checks.
+/// Block until a session is stored and unlocked, backing off between checks.
 ///
 /// `load` and `sleep` are parameters rather than direct calls so the backoff
 /// schedule can be tested without a keyring and without real time passing.
@@ -1861,6 +2166,16 @@ where
                 sleep(delay);
                 attempts = attempts.saturating_add(1);
             }
+            Err(pdfs_core::Error::Locked) => {
+                let delay = login_poll_delay(attempts);
+                if attempts == 0 {
+                    tracing::info!("account is locked; waiting for `pdfs unlock`…");
+                } else {
+                    tracing::debug!(delay_secs = delay.as_secs(), "account still locked");
+                }
+                sleep(delay);
+                attempts = attempts.saturating_add(1);
+            }
             Err(e) => return Err(e.into()),
         }
     }
@@ -1871,25 +2186,31 @@ where
 /// an external unmount triggers a remount; errors back off and retry. This is
 /// the entry point for the systemd user service.
 fn cmd_daemon(mountpoint: Option<PathBuf>) -> Result<()> {
+    // The daemon holds the account's key passphrases in memory; keep them out
+    // of core dumps and away from same-user ptrace.
+    pdfs_core::kernelkey::forbid_dumps();
     loop {
         // Wait until a session is stored. The GUI enables this service on login,
         // but the service may also start at boot before the user has logged in.
-        wait_for_session(|| auth::load().map(|_| ()), std::thread::sleep)?;
+        wait_for_session(auth::ready, pdfs_fuse::idle_sleep)?;
 
         match mount_once(mountpoint.clone()) {
             Ok(pdfs_fuse::MountOutcome::Shutdown) => {
                 tracing::info!("daemon stopping");
                 return Ok(());
             }
+            Ok(pdfs_fuse::MountOutcome::ResumeStored) => {
+                tracing::info!("resuming the session stored in the keyring");
+            }
             Ok(pdfs_fuse::MountOutcome::Unmounted) => {
                 tracing::warn!("mount ended externally; remounting in 2s");
-                std::thread::sleep(std::time::Duration::from_secs(2));
+                pdfs_fuse::idle_sleep(std::time::Duration::from_secs(2));
             }
             Err(e) => {
                 // `{:#}` so the whole anyhow chain lands in the log — the top
                 // context alone ("mount failed") never says *why*.
                 tracing::error!(error = format!("{e:#}"), "mount failed; retrying in 5s");
-                std::thread::sleep(std::time::Duration::from_secs(5));
+                pdfs_fuse::idle_sleep(std::time::Duration::from_secs(5));
             }
         }
     }
@@ -1947,13 +2268,22 @@ fn mount_once(mountpoint: Option<PathBuf>) -> Result<pdfs_fuse::MountOutcome> {
             sweep_mode: config.resolved_conflict_sweep(),
             upload_limit: config.upload_limit.unwrap_or(0),
             download_limit: config.download_limit.unwrap_or(0),
+            local_first: config.local_first.unwrap_or(true),
         },
     );
 
-    // Clean unmount check (as a best-effort final backup).
+    // Last chance for a rotation the keyring refused when it happened. Only
-    if let Err(e) = rt.block_on(auth::persist(&session)) {
+    // that: by now the keyring may hold a newer login, the one this stop was
-        tracing::debug!(error = %e, "no new tokens to persist on shutdown");
+    // restarted for, and the tokens of this session would overwrite it.
+    if let Err(e) = auth::persist(&session) {
+        tracing::error!(
+            error = %e,
+            "could not save the refreshed session tokens; the next start may need `pdfs login`"
+        );
     }
+    // Dropping the runtime waits for every blocking task, however long; a call
+    // still stuck on Drive would hold the stop until systemd kills it (B165).
+    rt.shutdown_timeout(std::time::Duration::from_secs(2));
 
     let outcome = result.context("mount failed")?;
     Ok(outcome)
@@ -3067,6 +3397,19 @@ fn cmd_diagnose() -> Result<()> {
     match pdfs_core::auth::load() {
         Ok(session) => {
             report.finding(DiagnoseLevel::Ok, "  keyring session", session.username);
+            match key_state_name() {
+                "locked" => report.finding(
+                    DiagnoseLevel::Fail,
+                    "  account keys",
+                    "locked — run `pdfs unlock` (the daemon waits for it)",
+                ),
+                "session" => report.finding(
+                    DiagnoseLevel::Ok,
+                    "  account keys",
+                    "unlocked for this login session",
+                ),
+                _ => report.finding(DiagnoseLevel::Ok, "  account keys", "stored in the keyring"),
+            }
         }
         Err(e) => {
             // A locked keyring and an absent login look the same from here, so
@@ -3097,6 +3440,8 @@ fn cmd_diagnose() -> Result<()> {
         Ok(CtlResponse::Status {
             mountpoint,
             online,
+            session_expired,
+            tokens_unsaved,
             pending_uploads,
             pending_changes,
             ..
@@ -3118,19 +3463,38 @@ fn cmd_diagnose() -> Result<()> {
                     |kind| format!("{mountpoint} ({kind})"),
                 ),
             );
-            report.finding(
+            // The keyring check above read the blob, which still holds the
-                if online {
+            // tokens the daemon could not replace.
-                    DiagnoseLevel::Ok
+            if tokens_unsaved {
-                } else {
+                report.finding(
-                    DiagnoseLevel::Warn
+                    DiagnoseLevel::Warn,
-                },
+                    "  session tokens",
-                "  network",
+                    "the keyring refuses the refreshed ones; unlock it, or a reboot needs `pdfs login`",
-                if online {
+                );
-                    "online"
+            }
-                } else {
+            // A refused session reads as offline too, but no connection will
-                    "offline; cached data remains available"
+            // bring it back, and the keyring check above cannot tell.
-                },
+            if session_expired {
-            );
+                report.finding(
+                    DiagnoseLevel::Fail,
+                    "  session",
+                    "Proton refused it (expired or revoked) — run `pdfs login`",
+                );
+            } else {
+                report.finding(
+                    if online {
+                        DiagnoseLevel::Ok
+                    } else {
+                        DiagnoseLevel::Warn
+                    },
+                    "  network",
+                    if online {
+                        "online"
+                    } else {
+                        "offline; cached data remains available"
+                    },
+                );
+            }
             let pending = pending_uploads + pending_changes;
             report.finding(
                 if pending == 0 {
@@ -3365,6 +3729,21 @@ mod login_wait_tests {
         );
     }
 
+    #[test]
+    fn a_locked_account_is_waited_on_until_it_is_unlocked() {
+        let mut checks = vec![
+            Ok(()),
+            Err(pdfs_core::Error::Locked),
+            Err(pdfs_core::Error::NotLoggedIn),
+            Err(pdfs_core::Error::Locked),
+        ];
+        let mut slept = 0;
+
+        wait_for_session(|| checks.pop().unwrap(), |_| slept += 1).unwrap();
+
+        assert_eq!(slept, 3, "locked and signed-out are both waited out");
+    }
+
     #[test]
     fn a_stored_session_is_not_waited_for_at_all() {
         let mut slept = 0;
@@ -3397,6 +3776,7 @@ mod login_wait_tests {
             shared_by_unverified: false,
             trashed_at: 0,
             trashed_from: None,
+            issue: None,
         };
         assert_eq!(shared_by_line(&entry), None, "no invitation, no line");
         entry.shared_by = "alice@proton.me".into();

crates/pdfs-core/Cargo.toml

@@ -28,3 +28,5 @@ dbus-secret-service-keyring-store.workspace = true
 parking_lot.workspace = true
 async-trait.workspace = true
 libc.workspace = true
+zeroize.workspace = true
+base64.workspace = true

crates/pdfs-core/src/cache.rs

@@ -91,7 +91,7 @@ const TOUCH_FLUSH_AT: usize = 256;
 ///
 /// Public because it is the *contract* a block has to satisfy, not a detail of
 /// this cache: the network read path validates against it too, so a block that
-/// comes back short is refused before it can truncate a file (bugs.md B84).
+/// comes back short is refused before it can truncate a file (`docs/BUGS.md` B84).
 pub fn block_len(size: u64, idx: u64) -> u64 {
     let start = idx.saturating_mul(BLOCK_SIZE);
     size.saturating_sub(start).min(BLOCK_SIZE)
@@ -311,8 +311,7 @@ struct PinFile {
     pins: BTreeMap<String, Pin>,
 }
 
-/// What a staged file actually contains, written beside it as `<name>.json`
+/// What a staged file actually contains, written beside it as `<name>.json`.
-/// (offline.md Phase 2).
 ///
 /// A staged file is **not** necessarily valid whole-file content, and that is
 /// the whole reason this exists. A partial overwrite commits by filling the
@@ -365,6 +364,14 @@ pub struct StagedWrite {
     pub based_on: Option<Baseline>,
 }
 
+impl StagedWrite {
+    /// Whether `authored` ranges cover a file of `len` bytes, so the staged
+    /// bytes are its complete new content. An empty file has nothing to cover.
+    pub fn covers(authored: &[(u64, u64)], len: u64) -> bool {
+        len == 0 || authored == [(0, len)]
+    }
+}
+
 /// The identity of a remote revision, as far as we can observe it.
 ///
 /// `revision_id` is the authoritative identity when present: the server assigns a
@@ -431,9 +438,9 @@ pub struct ContentCache {
     /// Subdirectory for write-handle scratch files (disk-backed write buffers).
     /// Emptied on open so a crashed run leaves no orphans.
     scratch_dir: PathBuf,
-    /// Subdirectory holding the bytes of writes that have not been uploaded yet
+    /// Subdirectory holding the bytes of writes that have not been uploaded yet.
-    /// (offline.md Phase 2/3) — every released write passes through here, since
+    /// Every released write passes through here, since the upload is a queued
-    /// the upload is a queued op performed later. Unlike `scratch_dir` this is
+    /// op performed later. Unlike `scratch_dir` this is
     /// **never** emptied on open: these are the only copy of content the user
     /// authored, and the whole point is that they outlive the daemon.
     staging_dir: PathBuf,
@@ -468,7 +475,7 @@ pub struct ContentCache {
     thumb_bytes: AtomicU64,
     /// Unified metadata DB. Its `cache_entries` table is the LRU index: every
     /// store/read/evict updates it, and the budget enforcers query it instead of
-    /// scanning the cache directories (plan.md P4).
+    /// scanning the cache directories.
     db: Arc<Db>,
     /// LRU touches not yet written to `cache_entries`, keyed by cache key.
     ///
@@ -837,6 +844,9 @@ impl ContentCache {
         }
         let bytes = std::fs::metadata(&tmp)?.len();
         std::fs::rename(&tmp, &blob)?;
+        // Linked from the blob already cached, the temp name was a second name
+        // of it, and the rename did nothing (`docs/BUGS.md` B187).
+        let _ = std::fs::remove_file(&tmp);
         let meta = serde_json::to_vec(&Meta { mtime, size })?;
         std::fs::write(self.meta_path(uid), meta)?;
         self.db
@@ -978,7 +988,7 @@ impl ContentCache {
     /// a miss ([`cached_block`](Self::cached_block) checks), so a bad block
     /// cannot escape this cache even though this does not check. Validating a
     /// block is the *reader's* job, at the point it is fetched — see
-    /// `Core::read_block` (bugs.md B84).
+    /// `Core::read_block` (`docs/BUGS.md` B84).
     pub fn store_block(
         &self,
         uid: &NodeUid,
@@ -1480,9 +1490,8 @@ impl ContentCache {
     /// This is what makes a write survive its upload: the caller is releasing a
     /// write handle and would otherwise delete the file, so until the bytes are
     /// on the remote, staging holds the only copy. Every dirty handle goes
-    /// through here — the upload is a queued op performed later (offline.md
+    /// through here — the upload is a queued op performed later, and a staged
-    /// Phase 3), and a staged file is also what a human can recover from if the
+    /// file is also what a human can recover from if the queue never drains.
-    /// queue never drains.
     ///
     /// Falls back to a copy when the rename crosses a filesystem boundary; a
     /// failure here means we could not save the bytes at all, so it is reported
@@ -2056,6 +2065,17 @@ mod tests {
         NodeUid::new(VolumeId::from("vol"), LinkId::from(link))
     }
 
+    #[test]
+    fn an_empty_write_covers_the_file_and_a_gap_does_not() {
+        assert!(
+            StagedWrite::covers(&[], 0),
+            "an empty file has nothing to cover"
+        );
+        assert!(StagedWrite::covers(&[(0, 7)], 7));
+        assert!(!StagedWrite::covers(&[(0, 3), (4, 7)], 7));
+        assert!(!StagedWrite::covers(&[], 7));
+    }
+
     /// A unique temp directory removed on drop; avoids a dev-dependency.
     struct TempDir(PathBuf);
     impl TempDir {
@@ -2178,6 +2198,24 @@ mod tests {
         assert_eq!(c.read_range(&u, 200, 5, 0, 5).unwrap(), b"newer");
     }
 
+    /// A landed create and the revision after it can adopt the same staged
+    /// blob. The link to the temp name is then a second name of the cached
+    /// blob, and a rename between two names of one file does nothing: the
+    /// temp name stayed until the next start swept it (`docs/BUGS.md` B187).
+    #[test]
+    fn store_file_twice_from_the_same_blob_leaves_no_temp_file() {
+        let (c, d) = cache();
+        let u = uid("a");
+        let src = d.path().join("staged-blob");
+        std::fs::write(&src, b"staged").unwrap();
+
+        c.store_file(&u, 100, 6, &src).unwrap();
+        c.store_file(&u, 100, 6, &src).unwrap();
+
+        assert!(!c.blob_path(&u).with_extension("tmp").exists());
+        assert_eq!(c.read_range(&u, 100, 6, 0, 6).unwrap(), b"staged");
+    }
+
     #[test]
     fn reconcile_rebuilds_index_from_disk() {
         let dir = TempDir::new();
@@ -2271,42 +2309,26 @@ mod tests {
     /// call also needs.
     #[test]
     fn budget_check_is_free_when_under_budget() {
-        use std::time::Instant;
-
         // Cap far above what we store, so every store stays under budget.
         let (c, _d) = cache_capped(1 << 30);
         let payload = vec![0u8; 4096];
-
+        for i in 0..8u64 {
-        // Cost of a store against a near-empty index...
-        let t = Instant::now();
-        for i in 0..500u64 {
             c.store_block(&uid("a"), 1, 1 << 30, blk(1 << 30, i), &payload)
                 .unwrap();
         }
-        let empty = t.elapsed() / 500;
 
-        // ...and against one with a few thousand entries in it.
+        // Plant an index row far over the cap behind the running total's back,
-        for i in 500..2500u64 {
+        // and older than every real block. Any budget check that consults the
-            c.store_block(&uid("a"), 1, 1 << 30, blk(1 << 30, i), &payload)
+        // index would see the pool over budget, evict, and reseed the total.
-                .unwrap();
+        c.db.cache_touch("planted", KIND_BLOCK, 1 << 40, 0).unwrap();
-        }
-        let t = Instant::now();
-        for i in 2500..3000u64 {
-            c.store_block(&uid("a"), 1, 1 << 30, blk(1 << 30, i), &payload)
-                .unwrap();
-        }
-        let full = t.elapsed() / 500;
 
-        println!("B4: store_block under budget — {empty:?} at ~0 entries, {full:?} at 2500");
+        c.store_block(&uid("a"), 1, 1 << 30, blk(1 << 30, 8), &payload)
-        // A ratio, not a wall-clock bound: the claim is that the under-budget
+            .unwrap();
-        // path does not grow with the index, and only a ratio tests that. An
+
-        // absolute threshold measures the machine's load instead, and this test
+        // Not a timing ratio: that measured the CI runner's load and flaked.
-        // runs alongside the rest of the suite.
+        assert_eq!(c.block_bytes.load(Ordering::Relaxed), 9 * 4096);
-        assert!(
+        let entries = c.db.cache_entries_by_kind(KIND_BLOCK).unwrap();
-            full < empty * 3,
+        assert_eq!(entries.len(), 10, "under-budget store evicted: {entries:?}");
-            "under-budget store should not scale with the index: \
-             {empty:?} at ~0 entries vs {full:?} at 2500"
-        );
     }
 
     /// The running totals are a fast path, not a second source of truth: after
@@ -2667,7 +2689,7 @@ mod tests {
     }
 
     /// The geometry the whole read path validates against, here and over the
-    /// network (bugs.md B84): full blocks, then whatever is left.
+    /// network (`docs/BUGS.md` B84): full blocks, then whatever is left.
     #[test]
     fn block_len_is_full_blocks_then_the_remainder() {
         let size = BLOCK_SIZE * 2 + 17;
@@ -2747,7 +2769,7 @@ mod tests {
     /// A cached block is addressed by the range it covers, not by its index
     /// alone. Re-planning a file onto its real geometry must therefore miss the
     /// blocks the uniform fallback cached, rather than serve their bytes at the
-    /// wrong offset (bugs.md B85).
+    /// wrong offset (`docs/BUGS.md` B85).
     #[test]
     fn a_cached_block_is_not_served_to_a_different_geometry() {
         let (c, _d) = cache();
@@ -2814,7 +2836,7 @@ mod tests {
 
     /// A block of the wrong length cannot escape the cache even though the
     /// store does not check: the read validates it and reports a miss, so the
-    /// next read refetches rather than serving a hole (bugs.md B84).
+    /// next read refetches rather than serving a hole (`docs/BUGS.md` B84).
     #[test]
     fn a_block_of_the_wrong_length_reads_as_a_miss() {
         let (c, _d) = cache();
@@ -2879,7 +2901,7 @@ mod tests {
         );
     }
 
-    /// A failed upload must never cost the user their bytes (offline.md Phase 2):
+    /// A failed upload must never cost the user their bytes:
     /// the scratch file moves to staging intact, and staging survives a reopen
     /// the way scratch deliberately does not.
     #[test]

crates/pdfs-core/src/config.rs

@@ -3,7 +3,7 @@
 use std::path::{Path, PathBuf};
 
 use directories::ProjectDirs;
-use serde::{Deserialize, Serialize};
+use serde::{Deserialize, Deserializer, Serialize};
 
 use crate::error::{Error, Result};
 use crate::menu::PromptConfig;
@@ -12,8 +12,19 @@ use crate::syncignore::DEFAULT_IGNORE_PATTERNS;
 
 /// Proton requires `external-drive-{name}@{semver}-{channel}` (channel ∈
 /// stable/beta/alpha); a malformed value trips the 422 anti-abuse path.
-pub const APP_VERSION: &str = "external-drive-linux@0.1.0-alpha";
+/// Follows the release so Proton can tell releases apart and retire old ones
-pub const USER_AGENT: &str = "proton-drive-linux/0.1.0";
+/// without retiring every one.
+pub const APP_VERSION: &str = concat!(
+    "external-drive-linux@",
+    env!("CARGO_PKG_VERSION"),
+    "-stable"
+);
+pub const USER_AGENT: &str = concat!("proton-drive-linux/", env!("CARGO_PKG_VERSION"));
+
+/// The fixed identity every release up to 3.1.0 wrote into `config.json`. Read
+/// back as "unset" so those configs follow the release instead of pinning it.
+const LEGACY_APP_VERSION: &str = "external-drive-linux@0.1.0-alpha";
+const LEGACY_USER_AGENT: &str = "proton-drive-linux/0.1.0";
 
 /// Keyring service name; one entry per credential kind keyed by username.
 pub const KEYRING_SERVICE: &str = "proton-drive-linux";
@@ -76,10 +87,24 @@ fn resolve_sweep_mode(env: Option<&str>, stored: Option<SweepMode>) -> SweepMode
 }
 
 /// Configuration structure allowing the user to customize client identification headers.
-#[derive(Serialize, Deserialize, Debug, Clone)]
+#[derive(Serialize, Deserialize, Debug, Clone, Default)]
 pub struct AppConfig {
-    pub app_version: String,
+    /// Override for [`APP_VERSION`]. `None` means "use the release's own";
-    pub user_agent: String,
+    /// the old fixed default reads as `None`, so it leaves the file on the
+    /// next save.
+    #[serde(
+        default,
+        deserialize_with = "identity_override",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub app_version: Option<String>,
+    /// Override for [`USER_AGENT`], handled like `app_version`.
+    #[serde(
+        default,
+        deserialize_with = "identity_override",
+        skip_serializing_if = "Option::is_none"
+    )]
+    pub user_agent: Option<String>,
     /// Soft cap on the on-disk content cache, in bytes (`0` = unlimited).
     /// `None` means "use [`DEFAULT_CACHE_BUDGET_BYTES`]"; the Settings page
     /// writes an explicit value here. Defaulted for configs predating the field.
@@ -154,6 +179,13 @@ pub struct AppConfig {
     /// configs predating the field.
     #[serde(default)]
     pub online_map: bool,
+    /// Record a new folder, a new file, a rename or a delete through the mount
+    /// locally and send it from the queue, instead of waiting for Drive in the
+    /// syscall. `None` means on. `false` brings back the old path for one
+    /// release (docs/ROADMAP.md). Defaulted for configs predating
+    /// the field.
+    #[serde(default)]
+    pub local_first: Option<bool>,
 }
 
 /// The My Files page's view choices, remembered between runs.
@@ -209,30 +241,28 @@ impl FileSort {
     }
 }
 
-impl Default for AppConfig {
+/// Reads an `app_version` or `user_agent` override, dropping the fixed
-    fn default() -> Self {
+/// identity older releases stored as the default.
-        Self {
+fn identity_override<'de, D: Deserializer<'de>>(
-            app_version: APP_VERSION.to_string(),
+    deserializer: D,
-            user_agent: USER_AGENT.to_string(),
+) -> std::result::Result<Option<String>, D::Error> {
-            cache_budget: None,
+    let value = Option::<String>::deserialize(deserializer)?;
-            upload_limit: None,
+    Ok(value.filter(|v| v != LEGACY_APP_VERSION && v != LEGACY_USER_AGENT))
-            download_limit: None,
-            mountpoint: None,
-            ignore_patterns: None,
-            device_uid: None,
-            conflict_sweep: None,
-            open_with: None,
-            prompt: None,
-            proton_theme: None,
-            files_view: FilesView::default(),
-            tray_hidden: false,
-            language: None,
-            online_map: false,
-        }
-    }
 }
 
 impl AppConfig {
+    /// The `x-pm-appversion` sent to Proton: the user's override, or
+    /// [`APP_VERSION`].
+    pub fn resolved_app_version(&self) -> &str {
+        self.app_version.as_deref().unwrap_or(APP_VERSION)
+    }
+
+    /// The `User-Agent` sent to Proton: the user's override, or
+    /// [`USER_AGENT`].
+    pub fn resolved_user_agent(&self) -> &str {
+        self.user_agent.as_deref().unwrap_or(USER_AGENT)
+    }
+
     /// The effective cache budget in bytes: the user's explicit choice, or
     /// [`DEFAULT_CACHE_BUDGET_BYTES`] when unset.
     pub fn resolved_cache_budget(&self) -> u64 {
@@ -424,7 +454,7 @@ impl AppDirs {
     /// typical umask makes them `0755`. Until this was fixed, the only thing
     /// keeping another local user out was `~/.cache` and `~/.local/state`
     /// happening to be `0700`, which is a convention of the user's system and
-    /// not something this client established (bugs.md B6).
+    /// not something this client established (`docs/BUGS.md` B6).
     ///
     /// Applied on every start, not just at creation: a directory that already
     /// exists with a permissive mode — restored from a backup that flattened
@@ -475,7 +505,7 @@ fn restrict_dir(dir: &Path) -> Result<()> {
 /// session — enumerate, read, upload, trash, share — without presenting any
 /// credential, since the daemon already holds one. It is an authority boundary,
 /// not merely private data, and `UnixListener::bind` applies the umask like any
-/// other file (bugs.md B6).
+/// other file (`docs/BUGS.md` B6).
 ///
 /// There is a window between `bind` and this call during which the socket
 /// carries the umask's mode. It is closed in practice by the containing
@@ -496,7 +526,7 @@ mod tests {
         std::fs::metadata(p).unwrap().permissions().mode() & 0o777
     }
 
-    /// bugs.md B6. A permissive mode here is not a cosmetic problem: these
+    /// `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.
     #[test]
@@ -563,8 +593,8 @@ mod tests {
     #[test]
     fn test_app_config_serialization() {
         let config = AppConfig {
-            app_version: "external-drive-test-client@1.0.0".to_string(),
+            app_version: Some("external-drive-test-client@1.0.0".to_string()),
-            user_agent: "test-agent/1.0".to_string(),
+            user_agent: Some("test-agent/1.0".to_string()),
             cache_budget: Some(1234),
             upload_limit: Some(500_000),
             download_limit: None,
@@ -584,11 +614,15 @@ mod tests {
             tray_hidden: true,
             language: Some("de".to_string()),
             online_map: true,
+            local_first: Some(false),
         };
         let json = serde_json::to_string(&config).unwrap();
         let decoded: AppConfig = serde_json::from_str(&json).unwrap();
-        assert_eq!(decoded.app_version, "external-drive-test-client@1.0.0");
+        assert_eq!(
-        assert_eq!(decoded.user_agent, "test-agent/1.0");
+            decoded.resolved_app_version(),
+            "external-drive-test-client@1.0.0"
+        );
+        assert_eq!(decoded.resolved_user_agent(), "test-agent/1.0");
         assert_eq!(decoded.proton_theme, Some(true));
         assert!(decoded.tray_hidden);
         assert!(decoded.online_map);
@@ -619,8 +653,55 @@ mod tests {
     #[test]
     fn test_default_app_config() {
         let default_config = AppConfig::default();
-        assert_eq!(default_config.app_version, APP_VERSION);
+        assert_eq!(default_config.resolved_app_version(), APP_VERSION);
-        assert_eq!(default_config.user_agent, USER_AGENT);
+        assert_eq!(default_config.resolved_user_agent(), USER_AGENT);
+    }
+
+    #[test]
+    fn the_client_identity_follows_the_release() {
+        let version = env!("CARGO_PKG_VERSION");
+        assert_eq!(
+            APP_VERSION,
+            format!("external-drive-linux@{version}-stable")
+        );
+        assert_eq!(USER_AGENT, format!("proton-drive-linux/{version}"));
+    }
+
+    #[test]
+    fn an_old_config_with_the_fixed_identity_follows_the_release() {
+        // Every config written up to 3.1.0 holds these two values, so they must
+        // not pin the identity once Proton retires 0.1.0.
+        let json = format!(
+            r#"{{"app_version":"{LEGACY_APP_VERSION}","user_agent":"{LEGACY_USER_AGENT}","tray_hidden":true}}"#
+        );
+        let decoded: AppConfig = serde_json::from_str(&json).unwrap();
+        assert_eq!(decoded.resolved_app_version(), APP_VERSION);
+        assert_eq!(decoded.resolved_user_agent(), USER_AGENT);
+        assert!(decoded.tray_hidden, "the rest of the config survives");
+
+        let saved = serde_json::to_string(&decoded).unwrap();
+        assert!(!saved.contains("app_version"), "{saved}");
+        assert!(!saved.contains("user_agent"), "{saved}");
+    }
+
+    #[test]
+    fn a_hand_set_client_identity_is_kept() {
+        let json = r#"{"app_version":"external-drive-linux@9.9.9-beta","user_agent":"custom/1"}"#;
+        let decoded: AppConfig = serde_json::from_str(json).unwrap();
+        assert_eq!(
+            decoded.resolved_app_version(),
+            "external-drive-linux@9.9.9-beta"
+        );
+        assert_eq!(decoded.resolved_user_agent(), "custom/1");
+        let saved = serde_json::to_string(&decoded).unwrap();
+        assert!(saved.contains("external-drive-linux@9.9.9-beta"), "{saved}");
+    }
+
+    #[test]
+    fn a_config_without_a_client_identity_loads() {
+        let decoded: AppConfig = serde_json::from_str("{}").unwrap();
+        assert_eq!(decoded.resolved_app_version(), APP_VERSION);
+        assert_eq!(decoded.resolved_user_agent(), USER_AGENT);
     }
 
     #[test]

crates/pdfs-core/src/control.rs

@@ -443,11 +443,18 @@ pub enum Request {
     DeleteDevice { uid: String },
     /// Adopt an existing device as this machine's, pinning its uid in
     /// `config.json` so a hostname change or reinstall re-attaches to it instead
-    /// of registering a duplicate (features.md 5.1). `uid: None` clears the pin.
+    /// of registering a duplicate. `uid: None` clears the pin.
     /// Replies with [`Response::Ok`].
     AdoptDevice { uid: Option<String> },
+    /// Move every folder another device backs up into this machine's own
+    /// device, as server-side moves on the main volume. The other device stays
+    /// registered, without those folders. Sync folders here that already track
+    /// one of them follow it to its new share. Nothing is downloaded: the moved
+    /// folders are then offered by [`Request::ListRestorableFolders`].
+    /// Replies with [`Response::Ok`].
+    MigrateDevice { uid: String },
 
-    // ---- device folder sync (devices.md) ----------------------------------
+    // ---- device folder sync ----------------------------------
     /// 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 },
@@ -477,6 +484,15 @@ pub enum Request {
     /// Retry a backed-off queued op now instead of waiting out its backoff;
     /// every failed op when `id` is `None`. Replies with [`Response::Ok`].
     RetryPendingOp { id: Option<i64> },
+    /// Copy the content of a queued upload (`id` from
+    /// [`Request::ListPendingOps`]) to `dest`, an absolute path that must not
+    /// exist yet. The op stays queued. Replies with [`Response::Ok`].
+    ExportPendingOp { id: i64, dest: String },
+    /// Drop a queued change (`id` from [`Request::ListPendingOps`]) and undo
+    /// it locally: a node made here goes, a node Drive has goes back to what
+    /// Drive has, along with every other change queued on it. Its content is
+    /// lost unless it was exported first. Replies with [`Response::Ok`].
+    DiscardPendingOp { id: i64 },
     /// List the `(sync-conflict …)` copies under My Files and in synced
     /// folders. Replies with
     /// [`Response::Conflicts`].
@@ -487,7 +503,7 @@ pub enum Request {
     /// [`Response::Ok`].
     ResolveConflict { path: String, keep: ConflictKeep },
     /// List the folders under this machine's device that can be synced here,
-    /// each with a proposed local path (features.md 5.2). Replies with
+    /// each with a proposed local path. Replies with
     /// [`Response::RestorableFolders`].
     ListRestorableFolders,
     /// Attach the given remote device folders to local paths and sync them down.
@@ -880,6 +896,59 @@ pub struct PendingOpInfo {
     pub parked: bool,
     /// Failed often enough to count as stuck.
     pub failing: bool,
+    /// Why Drive refused it, when it did; such an op needs attention at once.
+    #[serde(default)]
+    pub issue: Option<SyncIssue>,
+    /// Carries file content that [`Request::ExportPendingOp`] can save.
+    #[serde(default)]
+    pub exportable: bool,
+}
+
+/// Why Drive refused a queued change (in [`PendingOpInfo`]). The change stays
+/// queued and keeps being retried; nothing is deleted.
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum SyncIssue {
+    /// The account's storage is full.
+    Quota,
+    /// The account may no longer change the file or its folder, for example
+    /// because a share was revoked.
+    Access,
+    /// The file or the folder it goes into is gone from Drive.
+    Missing,
+    /// The folder holds too many items, or is nested too deep.
+    Limit,
+    /// Drive rejected the change, for example a name it does not accept.
+    Rejected,
+    /// An issue from a newer daemon.
+    #[serde(other)]
+    Unknown,
+}
+
+impl SyncIssue {
+    /// The name stored in the database and sent on the wire.
+    pub fn as_str(self) -> &'static str {
+        match self {
+            SyncIssue::Quota => "quota",
+            SyncIssue::Access => "access",
+            SyncIssue::Missing => "missing",
+            SyncIssue::Limit => "limit",
+            SyncIssue::Rejected => "rejected",
+            SyncIssue::Unknown => "unknown",
+        }
+    }
+
+    /// The issue stored as `name`.
+    pub fn parse(name: &str) -> Self {
+        match name {
+            "quota" => SyncIssue::Quota,
+            "access" => SyncIssue::Access,
+            "missing" => SyncIssue::Missing,
+            "limit" => SyncIssue::Limit,
+            "rejected" => SyncIssue::Rejected,
+            _ => SyncIssue::Unknown,
+        }
+    }
 }
 
 /// One synced local folder on this machine's device (in [`Response::SyncFolders`]).
@@ -1156,6 +1225,12 @@ pub struct JobItem {
     /// Steps known to need doing, or `0` when unknown (indeterminate progress).
     /// May *grow* mid-job as more work is discovered.
     pub total: u64,
+    /// Housekeeping that changes nothing in the user's files: a mirror folder
+    /// scan that finds nothing to do yet, an index rebuild, a cache check. Front
+    /// ends may show it, but should not report the drive as busy over it. Absent
+    /// from older daemons, which never set it.
+    #[serde(default)]
+    pub background: bool,
 }
 
 /// One in-flight transfer in a [`Response::Transfers`] snapshot.
@@ -1234,6 +1309,10 @@ pub struct DirEntry {
     /// not known, and for anything not in the trash.
     #[serde(default)]
     pub trashed_from: Option<String>,
+    /// Why Drive refused a change queued on the node, for a [`Request::ListDir`]
+    /// entry; `None` otherwise.
+    #[serde(default)]
+    pub issue: Option<SyncIssue>,
 }
 
 /// One hit in a [`Request::Search`] result. Like [`DirEntry`] but carries the
@@ -1837,17 +1916,17 @@ pub enum Response {
         /// The pin registry.
         pins: Vec<Pin>,
         /// False when the daemon is serving the cached tree because the API is
-        /// unreachable (offline.md Phase 1). Cached and pinned content still
+        /// unreachable. Cached and pinned content still
         /// reads; anything else fails until the network is back.
         #[serde(default = "default_online")]
         online: bool,
-        /// Writes accepted locally but not yet uploaded (offline.md Phase 3).
+        /// Writes accepted locally but not yet uploaded.
         /// Non-zero means the mount is ahead of the remote — either a copy is
         /// still draining, or it cannot drain because we are offline.
         #[serde(default)]
         pending_uploads: u64,
-        /// Queued mutations that carry no bytes: `mkdir`, `rename`, `trash`
+        /// Queued mutations that carry no bytes: `mkdir`, `rename`, `trash`.
-        /// (offline.md Phase 3b). Counted apart from `pending_uploads` because
+        /// Counted apart from `pending_uploads` because
         /// calling a queued `mkdir` an upload is a lie.
         #[serde(default)]
         pending_changes: u64,
@@ -1880,6 +1959,16 @@ pub enum Response {
         /// resumed, or not paused.
         #[serde(default)]
         paused_until: Option<i64>,
+        /// True when Proton refused the session itself (refresh token refused,
+        /// account deleted or disabled). `online` is false then too, but no
+        /// connection brings it back: only signing in again does.
+        #[serde(default)]
+        session_expired: bool,
+        /// True while the keyring refuses the session's refreshed tokens. The
+        /// daemon keeps retrying; until it succeeds, a reboot signs the user
+        /// out.
+        #[serde(default)]
+        tokens_unsaved: bool,
     },
     /// A human-readable success message.
     Ok { message: String },
@@ -3016,6 +3105,9 @@ mod tests {
                 uid: Some("dev-1".into()),
             },
             Request::AdoptDevice { uid: None },
+            Request::MigrateDevice {
+                uid: "dev-2".into(),
+            },
             Request::ListRestorableFolders,
             Request::RestoreSyncFolders {
                 items: vec![RestoreItem {
@@ -3290,6 +3382,17 @@ mod tests {
                 },
                 r#"{"SaveRevisionAsByUid":{"uid":"vol~link","revision_id":"rev-3","dest":"/tmp/out.bin"}}"#,
             ),
+            (
+                Request::ExportPendingOp {
+                    id: 7,
+                    dest: "/tmp/out.bin".into(),
+                },
+                r#"{"ExportPendingOp":{"id":7,"dest":"/tmp/out.bin"}}"#,
+            ),
+            (
+                Request::DiscardPendingOp { id: 7 },
+                r#"{"DiscardPendingOp":{"id":7}}"#,
+            ),
         ];
         for (request, wire) in cases {
             assert_eq!(serde_json::to_string(&request).unwrap(), wire);
@@ -3298,6 +3401,25 @@ mod tests {
         }
     }
 
+    /// A daemon that predates sync issues sends neither field, and a newer one
+    /// may send an issue this build does not know.
+    #[test]
+    fn a_queued_op_from_another_daemon_version_still_decodes() {
+        let old = r#"{"id":1,"kind":"create","path":"a.txt","attempts":0,"last_error":null,
+            "queued_at":5,"next_attempt_at":5,"parked":false,"failing":false}"#;
+        let op: PendingOpInfo = serde_json::from_str(old).unwrap();
+        assert_eq!(op.issue, None);
+        assert!(!op.exportable);
+
+        let newer = old.replace(r#""failing":false"#, r#""failing":true,"issue":"embargo""#);
+        let op: PendingOpInfo = serde_json::from_str(&newer).unwrap();
+        assert_eq!(op.issue, Some(SyncIssue::Unknown));
+        assert_eq!(
+            SyncIssue::parse(SyncIssue::Quota.as_str()),
+            SyncIssue::Quota
+        );
+    }
+
     /// A front-end that predates the favorites filter sends no `favorites`
     /// field, and must keep getting the whole timeline rather than an empty page.
     #[test]

crates/pdfs-core/src/db/fixtures/v2.8.2.sql

@@ -0,0 +1,249 @@
+/* WARNING: Script requires that SQLITE_DBCONFIG_DEFENSIVE be disabled */
+PRAGMA foreign_keys=OFF;
+BEGIN TRANSACTION;
+CREATE TABLE sync_state (key TEXT PRIMARY KEY, value TEXT);
+INSERT INTO sync_state VALUES('schema_version','35');
+CREATE TABLE nodes (
+  uid           TEXT PRIMARY KEY,
+  parent_uid    TEXT,
+  name          TEXT NOT NULL,
+  is_dir        INTEGER NOT NULL,
+  size          INTEGER,
+  mtime         INTEGER NOT NULL,
+  revision_hash TEXT,
+  trashed       INTEGER NOT NULL DEFAULT 0
+, node_json TEXT, listed INTEGER NOT NULL DEFAULT 0, path TEXT);
+INSERT INTO nodes VALUES('vol~root',NULL,'My Files',1,0,200,NULL,0,'{"uid":{"volume_id":"vol","link_id":"root"},"parent_uid":null,"kind":"Folder","name":"My Files","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',0,'');
+INSERT INTO nodes VALUES('vol~docs','vol~root','Docs',1,0,200,NULL,0,'{"uid":{"volume_id":"vol","link_id":"docs"},"parent_uid":{"volume_id":"vol","link_id":"root"},"kind":"Folder","name":"Docs","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',0,'Docs');
+INSERT INTO nodes VALUES('vol~report','vol~docs','report.txt',0,10,200,NULL,0,'{"uid":{"volume_id":"vol","link_id":"report"},"parent_uid":{"volume_id":"vol","link_id":"docs"},"kind":{"File":{"media_type":"text/plain","total_size_on_storage":20,"active_revision_state":null,"active_revision_id":null,"claimed_size":10,"claimed_modification_time":null,"content_sha1":null}},"name":"report.txt","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',0,'Docs/report.txt');
+INSERT INTO nodes VALUES('vol~old','vol~docs','old.txt',0,3,200,NULL,0,'{"uid":{"volume_id":"vol","link_id":"old"},"parent_uid":{"volume_id":"vol","link_id":"docs"},"kind":{"File":{"media_type":"text/plain","total_size_on_storage":13,"active_revision_state":null,"active_revision_id":null,"claimed_size":3,"claimed_modification_time":null,"content_sha1":null}},"name":"old.txt","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',0,'Docs/old.txt');
+INSERT INTO nodes VALUES('vol~shared','vol~docs','shared.txt',0,4,200,NULL,0,'{"uid":{"volume_id":"vol","link_id":"shared"},"parent_uid":{"volume_id":"vol","link_id":"docs"},"kind":{"File":{"media_type":"text/plain","total_size_on_storage":14,"active_revision_state":null,"active_revision_id":null,"claimed_size":4,"claimed_modification_time":null,"content_sha1":null}},"name":"shared.txt","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',0,'Docs/shared.txt');
+INSERT INTO nodes VALUES('local~dir','vol~root','Offline folder',1,0,200,NULL,0,'{"uid":{"volume_id":"local","link_id":"dir"},"parent_uid":{"volume_id":"vol","link_id":"root"},"kind":"Folder","name":"Offline folder","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',1,'Offline folder');
+INSERT INTO nodes VALUES('local~inner','local~dir','inner.txt',0,5,200,NULL,0,'{"uid":{"volume_id":"local","link_id":"inner"},"parent_uid":{"volume_id":"local","link_id":"dir"},"kind":{"File":{"media_type":"text/plain","total_size_on_storage":15,"active_revision_state":null,"active_revision_id":null,"claimed_size":5,"claimed_modification_time":null,"content_sha1":null}},"name":"inner.txt","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',0,'Offline folder/inner.txt');
+INSERT INTO nodes VALUES('local~part','vol~root','movie.part',0,7,200,NULL,0,'{"uid":{"volume_id":"local","link_id":"part"},"parent_uid":{"volume_id":"vol","link_id":"root"},"kind":{"File":{"media_type":"text/plain","total_size_on_storage":17,"active_revision_state":null,"active_revision_id":null,"claimed_size":7,"claimed_modification_time":null,"content_sha1":null}},"name":"movie.part","creation_time":100,"modification_time":200,"trashed":false,"is_shared":false,"is_shared_publicly":false,"signature_email":null,"membership":null,"direct_role":null,"share_id":null,"photo":null,"album":null,"verification":{"name":"NotSigned","passphrase":"NotSigned","content_key":null,"extended_attributes":null}}',0,'movie.part');
+CREATE TABLE cache_entries (
+  cache_key     TEXT PRIMARY KEY,
+  size_bytes    INTEGER,
+  last_accessed INTEGER,
+  is_pinned     INTEGER NOT NULL DEFAULT 0
+, kind TEXT NOT NULL DEFAULT 'blob');
+CREATE TABLE pins (
+  uid       TEXT PRIMARY KEY,
+  path      TEXT NOT NULL,
+  recursive INTEGER NOT NULL DEFAULT 0
+);
+CREATE TABLE local_files (
+  id       INTEGER PRIMARY KEY,
+  path     TEXT NOT NULL UNIQUE,
+  name     TEXT NOT NULL,
+  is_dir   INTEGER NOT NULL,
+  size     INTEGER NOT NULL DEFAULT 0,
+  mtime    INTEGER NOT NULL DEFAULT 0,
+  scan_gen INTEGER NOT NULL DEFAULT 0
+);
+CREATE TABLE photos (
+  uid          TEXT PRIMARY KEY,
+  capture_time INTEGER NOT NULL,
+  name         TEXT,
+  ratio        REAL,
+  thumb_state  INTEGER NOT NULL DEFAULT 0,
+  seq          INTEGER NOT NULL
+, media_type TEXT, kind INTEGER NOT NULL DEFAULT 0, favorite INTEGER NOT NULL DEFAULT 0, content_hash TEXT, main_uid TEXT, group_key TEXT, resolved_at INTEGER, latitude REAL, longitude REAL, place_id INTEGER, similar_hash INTEGER);
+CREATE TABLE trash (
+  uid    TEXT PRIMARY KEY,
+  name   TEXT NOT NULL,
+  is_dir INTEGER NOT NULL,
+  size   INTEGER NOT NULL DEFAULT 0,
+  mtime  INTEGER NOT NULL DEFAULT 0
+, parent_uid TEXT, trashed_at INTEGER);
+CREATE TABLE device (
+  uid      TEXT PRIMARY KEY,
+  share_id TEXT NOT NULL,
+  root_uid TEXT NOT NULL,
+  name     TEXT NOT NULL,
+  created  INTEGER NOT NULL DEFAULT 0
+);
+CREATE TABLE sync_folder (
+  id              INTEGER PRIMARY KEY,
+  local_path      TEXT NOT NULL UNIQUE,
+  remote_uid      TEXT NOT NULL,
+  remote_share_id TEXT NOT NULL,
+  mode            TEXT NOT NULL DEFAULT 'mirror',
+  state           TEXT NOT NULL DEFAULT 'idle',
+  last_sync       INTEGER NOT NULL DEFAULT 0
+, pending_mode TEXT);
+CREATE TABLE sync_entry (
+  folder_id   INTEGER NOT NULL,
+  rel_path    TEXT NOT NULL,
+  remote_uid  TEXT,
+  local_mtime INTEGER NOT NULL DEFAULT 0,
+  local_size  INTEGER NOT NULL DEFAULT 0,
+  remote_hash TEXT,
+  remote_rev  TEXT, local_mtime_ns INTEGER,
+  PRIMARY KEY (folder_id, rel_path)
+);
+CREATE TABLE activity (
+  id     INTEGER PRIMARY KEY,
+  time   INTEGER NOT NULL,
+  kind   TEXT NOT NULL,
+  target TEXT NOT NULL,
+  detail TEXT NOT NULL DEFAULT '',
+  ok     INTEGER NOT NULL DEFAULT 1
+);
+CREATE TABLE pending_op (
+  id              INTEGER PRIMARY KEY,
+  kind            TEXT NOT NULL,
+  uid             TEXT NOT NULL,
+  blob_path       TEXT,
+  meta_json       TEXT,
+  created_at      INTEGER NOT NULL,
+  attempts        INTEGER NOT NULL DEFAULT 0,
+  last_error      TEXT,
+  next_attempt_at INTEGER NOT NULL DEFAULT 0
+, parent_uid TEXT, name TEXT, claimed_at INTEGER NOT NULL DEFAULT 0, access_deferred_since INTEGER NOT NULL DEFAULT 0);
+INSERT INTO pending_op VALUES(1,'mkdir','local~dir',NULL,NULL,1700000000000,0,NULL,0,'vol~root','Offline folder',4611686018427387903,0);
+INSERT INTO pending_op VALUES(2,'create','local~inner','/blobs/inner','{"len":5,"mtime":1700000000,"based_on":null}',1700000000000,0,NULL,0,'local~dir','inner.txt',0,0);
+INSERT INTO pending_op VALUES(3,'create','local~part','/blobs/part','{"len":5,"mtime":1700000000,"based_on":null}',1700000000000,0,NULL,8000000000000,'vol~root','movie.part',0,0);
+INSERT INTO pending_op VALUES(4,'revision','vol~report','/blobs/report','{"len":5,"mtime":1700000000,"based_on":null}',1700000000000,2,'network unreachable',1700000900000,NULL,NULL,0,0);
+INSERT INTO pending_op VALUES(5,'rename','vol~shared',NULL,'{"original_parent_uid":"vol~docs","original_name":"shared.txt"}',1700000000000,0,NULL,1700000700000,'vol~root','shared-moved.txt',0,1700000100000);
+INSERT INTO pending_op VALUES(6,'trash','vol~old',NULL,NULL,1700000000000,0,NULL,0,NULL,NULL,0,0);
+CREATE TABLE IF NOT EXISTS 'local_fts_data'(id INTEGER PRIMARY KEY, block BLOB);
+INSERT INTO local_fts_data VALUES(1,x'000000');
+INSERT INTO local_fts_data VALUES(10,x'00000000000000');
+CREATE TABLE IF NOT EXISTS 'local_fts_idx'(segid, term, pgno, PRIMARY KEY(segid, term)) WITHOUT ROWID;
+CREATE TABLE IF NOT EXISTS 'local_fts_docsize'(id INTEGER PRIMARY KEY, sz BLOB);
+CREATE TABLE IF NOT EXISTS 'local_fts_config'(k PRIMARY KEY, v) WITHOUT ROWID;
+INSERT INTO local_fts_config VALUES('version',4);
+CREATE TABLE share_access (
+  root_uid TEXT PRIMARY KEY,
+  access   TEXT NOT NULL
+           CHECK (access IN ('owner', 'editor', 'viewer', 'unknown'))
+);
+CREATE TABLE mount (
+  id              INTEGER PRIMARY KEY,
+  kind            TEXT NOT NULL
+                  CHECK (kind IN ('myfiles', 'device', '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 = 'device' 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)
+  )
+);
+CREATE TABLE albums (
+  uid           TEXT PRIMARY KEY,
+  name          TEXT NOT NULL,
+  photo_count   INTEGER NOT NULL DEFAULT 0,
+  cover_uid     TEXT,
+  last_activity INTEGER,
+  shared        INTEGER NOT NULL DEFAULT 0,
+  seq           INTEGER NOT NULL
+);
+CREATE TABLE album_photos (
+  album_uid    TEXT NOT NULL,
+  uid          TEXT NOT NULL,
+  capture_time INTEGER NOT NULL,
+  name         TEXT,
+  media_type   TEXT,
+  kind         INTEGER NOT NULL DEFAULT 0,
+  ratio        REAL,
+  thumb_state  INTEGER NOT NULL DEFAULT 0,
+  seq          INTEGER NOT NULL,
+  PRIMARY KEY (album_uid, uid)
+);
+CREATE TABLE IF NOT EXISTS 'nodes_fts_data'(id INTEGER PRIMARY KEY, block BLOB);
+INSERT INTO nodes_fts_data VALUES(1,x'083850');
+INSERT INTO nodes_fts_data VALUES(10,x'000000000108080008010101020101030101040101050101060101070101080101');
+INSERT INTO nodes_fts_data VALUES(137438953473,x'000000340430206669010204010366696c0102050103696c6501020601036c657301020701036d79200102020103792066010203040808080808');
+INSERT INTO nodes_fts_data VALUES(274877906945,x'0000001a0430646f6302080201010201036f6373020803010103040b');
+INSERT INTO nodes_fts_data VALUES(412316860417,x'0000008b04302e747803080801010d01032f72650306010106010363732f03060101040103646f630306010102010365706f03080301010801036f637303060101030202727403080501010a0103706f7203080401010901037265700308020101070202742e03080601010b0103732f7203060101050103742e7403080701010c0202787403080901010e040b0a0a0a0b0a0a0b0b0a0a0b');
+INSERT INTO nodes_fts_data VALUES(549755813889,x'0000006b04302e747804080501010a01032f6f6c0406010106010363732f04060101040103642e7404080401010902026f63040601010201036c642e04080301010801036f6373040601010302026c640408020101070103732f6f0406010105010374787404080601010b040b0a0a0b090b0a0a0a');
+INSERT INTO nodes_fts_data VALUES(687194767361,x'0000008c04302e747805080801010d01032f736805060101060103617265050804010109010363732f05060101040103642e7405080701010c02026f630506010102010365642e05080601010b010368617205080301010801036f63730506010103010372656405080501010a0103732f73050601010502026861050802010107010374787405080901010e040b0a0b0a0b090b0b0a0b0a0a');
+INSERT INTO nodes_fts_data VALUES(824633720833,x'00000084043020666f060809010109010364657206080d01010d0103652066060808010108010366666c06080301010302026c6906080401010402026f6c06080a01010a0103696e6506080601010601036c646506080c01010c0202696e06080501010501036e652006080701010701036f666606080201010202026c6406080b01010b040b0b0b0b0a0a0b0b0a0b0b');
+INSERT INTO nodes_fts_data VALUES(962072674305,x'000000da043020666f070601010901032e747807080701011601032f696e07060101100103646572070601010d010365206607060101080202722e07080501011403012f070601010e010366666c070601010302026c69070601010402026f6c070601010a0103696e65070601010603016e07080201011101036c6465070601010c0202696e070601010501036e6520070601010703017207080401011302026e6507080301011201036f6666070601010202026c64070601010b0103722e7407080601011502022f69070601010f0103747874070808010117040a0b0a0a0a0a080a09090a090a090a090a0a090b09');
+INSERT INTO nodes_fts_data VALUES(1099511627777,x'0000005c04302e706108080701010701036172740808090101090103652e70080806010106010369652e08080501010501036d6f7608080201010201036f766908080301010301037061720808080101080103766965080804010104040b0b0b0b0b0b0b');
+CREATE TABLE IF NOT EXISTS 'nodes_fts_idx'(segid, term, pgno, PRIMARY KEY(segid, term)) WITHOUT ROWID;
+INSERT INTO nodes_fts_idx VALUES(1,x'',2);
+INSERT INTO nodes_fts_idx VALUES(2,x'',2);
+INSERT INTO nodes_fts_idx VALUES(3,x'',2);
+INSERT INTO nodes_fts_idx VALUES(4,x'',2);
+INSERT INTO nodes_fts_idx VALUES(5,x'',2);
+INSERT INTO nodes_fts_idx VALUES(6,x'',2);
+INSERT INTO nodes_fts_idx VALUES(7,x'',2);
+INSERT INTO nodes_fts_idx VALUES(8,x'',2);
+CREATE TABLE IF NOT EXISTS 'nodes_fts_content'(id INTEGER PRIMARY KEY, c0, c1);
+INSERT INTO nodes_fts_content VALUES(1,'My Files','');
+INSERT INTO nodes_fts_content VALUES(2,'Docs','Docs');
+INSERT INTO nodes_fts_content VALUES(3,'report.txt','Docs/report.txt');
+INSERT INTO nodes_fts_content VALUES(4,'old.txt','Docs/old.txt');
+INSERT INTO nodes_fts_content VALUES(5,'shared.txt','Docs/shared.txt');
+INSERT INTO nodes_fts_content VALUES(6,'Offline folder','Offline folder');
+INSERT INTO nodes_fts_content VALUES(7,'inner.txt','Offline folder/inner.txt');
+INSERT INTO nodes_fts_content VALUES(8,'movie.part','movie.part');
+CREATE TABLE IF NOT EXISTS 'nodes_fts_docsize'(id INTEGER PRIMARY KEY, sz BLOB);
+INSERT INTO nodes_fts_docsize VALUES(1,x'0600');
+INSERT INTO nodes_fts_docsize VALUES(2,x'0202');
+INSERT INTO nodes_fts_docsize VALUES(3,x'080d');
+INSERT INTO nodes_fts_docsize VALUES(4,x'050a');
+INSERT INTO nodes_fts_docsize VALUES(5,x'080d');
+INSERT INTO nodes_fts_docsize VALUES(6,x'0c0c');
+INSERT INTO nodes_fts_docsize VALUES(7,x'0716');
+INSERT INTO nodes_fts_docsize VALUES(8,x'0808');
+CREATE TABLE IF NOT EXISTS 'nodes_fts_config'(k PRIMARY KEY, v) WITHOUT ROWID;
+INSERT INTO nodes_fts_config VALUES('version',4);
+CREATE TABLE own_sealed_rev (
+  uid         TEXT PRIMARY KEY,
+  revision_id TEXT NOT NULL,
+  sealed_at   INTEGER NOT NULL
+);
+INSERT INTO own_sealed_rev VALUES('vol~report','rev-1',1700000000000);
+PRAGMA writable_schema=ON;
+INSERT INTO sqlite_schema(type,name,tbl_name,rootpage,sql)VALUES('table','local_fts','local_fts',0,'CREATE VIRTUAL TABLE local_fts USING fts5(
+  name, path, content=''local_files'', content_rowid=''id'', tokenize=''trigram''
+)');
+INSERT INTO sqlite_schema(type,name,tbl_name,rootpage,sql)VALUES('table','nodes_fts','nodes_fts',0,'CREATE VIRTUAL TABLE nodes_fts USING fts5(
+  name, path, tokenize=''trigram''
+)');
+CREATE TRIGGER mount_sync_folder_insert
+AFTER INSERT ON sync_folder
+BEGIN
+  INSERT OR IGNORE INTO mount (kind, sync_folder_id)
+  VALUES ('device', NEW.id);
+END;
+CREATE INDEX idx_nodes_parent ON nodes(parent_uid);
+CREATE INDEX idx_photos_seq ON photos(seq);
+CREATE INDEX pending_op_uid ON pending_op(uid);
+CREATE INDEX pending_op_parent ON pending_op(parent_uid);
+CREATE INDEX cache_entries_lru ON cache_entries(kind, last_accessed);
+CREATE INDEX idx_nodes_name_nocase ON nodes(name COLLATE NOCASE);
+CREATE INDEX idx_local_files_name_nocase
+  ON local_files(name COLLATE NOCASE);
+CREATE UNIQUE INDEX mount_myfiles
+  ON mount(kind) WHERE kind = 'myfiles';
+CREATE UNIQUE INDEX mount_device
+  ON mount(sync_folder_id) WHERE kind = 'device';
+CREATE UNIQUE INDEX mount_shared
+  ON mount(share_root_uid) WHERE kind = 'shared';
+CREATE INDEX idx_album_photos_seq ON album_photos(album_uid, seq);
+CREATE INDEX idx_album_photos_uid ON album_photos(uid);
+CREATE INDEX idx_photos_favorite ON photos(favorite, seq);
+CREATE INDEX idx_sync_entry_remote_uid ON sync_entry(remote_uid);
+CREATE INDEX idx_local_files_scan_gen ON local_files(scan_gen);
+CREATE INDEX idx_nodes_parent_live ON nodes(parent_uid) WHERE trashed = 0;
+CREATE INDEX idx_pending_op_claimed
+    ON pending_op(uid) WHERE claimed_at <> 0;
+CREATE INDEX idx_trash_parent ON trash(parent_uid);
+CREATE INDEX idx_photos_group ON photos(group_key);
+CREATE INDEX idx_photos_unresolved ON photos(resolved_at);
+CREATE INDEX idx_photos_place ON photos(place_id);
+PRAGMA writable_schema=OFF;
+COMMIT;

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

@@ -1,4 +1,4 @@
-//! Database health reporting and repair (features.md 4.3).
+//! Database health reporting and repair.
 //!
 //! Everything here exists for the case where something has already gone wrong:
 //! a crash mid-write, a full disk, a cache that has grown out of proportion to

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

@@ -5,11 +5,13 @@
 //! is already on disk somewhere, so a change here would silently diverge from
 //! what an existing install actually has. Add a new one instead.
 
+use rusqlite::OptionalExtension;
+
 use super::Db;
 use crate::Result;
 
 /// Current schema version. Bump on every forward migration added below.
-pub(super) const SCHEMA_VERSION: i64 = 35;
+pub(super) const SCHEMA_VERSION: i64 = 42;
 
 impl Db {
     pub(super) fn migrate(&self) -> Result<()> {
@@ -332,6 +334,112 @@ impl Db {
                 tx.execute_batch(MIGRATION_V35)?;
             }
         }
+        if current < 36 {
+            // Same guards as V26-V35.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('nodes') WHERE name = 'lid'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            let has_nodes: bool = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'nodes'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            if has_nodes && !has_column {
+                tx.execute_batch(MIGRATION_V36)?;
+            }
+        }
+        if current < 37 {
+            // Same guards as V26-V36.
+            let sql: Option<String> = tx
+                .query_row(
+                    "SELECT sql FROM sqlite_master WHERE type = 'table' AND name = 'pending_op'",
+                    [],
+                    |row| row.get(0),
+                )
+                .optional()?;
+            if sql.is_some_and(|sql| !sql.contains("AUTOINCREMENT")) {
+                tx.execute_batch(MIGRATION_V37)?;
+            }
+        }
+        if current < 38 {
+            // Same guards as V26-V37.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('pending_op') WHERE name = 'issue'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            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 && !has_column {
+                tx.execute_batch(MIGRATION_V38)?;
+            }
+        }
+        if current < 39 {
+            // Same guards as V26-V38.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('pending_op') WHERE name = 'lid'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            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 && !has_column {
+                tx.execute_batch(MIGRATION_V39)?;
+            }
+        }
+        if current < 40 {
+            // Same guards as V26-V39.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('nodes') WHERE name = 'parent_lid'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            let has_nodes: bool = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'nodes'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            if has_nodes && !has_column {
+                tx.execute_batch(MIGRATION_V40)?;
+            }
+        }
+        if current < 41 {
+            // Needs both tables; on a database that never had them there is
+            // nothing to rewrite.
+            let tables: i64 = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master
+                 WHERE type = 'table' AND name IN ('nodes', 'pending_op', 'pins')",
+                [],
+                |row| row.get(0),
+            )?;
+            if tables == 3 {
+                tx.execute_batch(MIGRATION_V41)?;
+            }
+        }
+        if current < 42 {
+            // Same guards as V26-V40.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('pending_op') WHERE name = 'sent_sha1'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            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 && !has_column {
+                tx.execute_batch(MIGRATION_V42)?;
+            }
+        }
         tx.execute(
             "INSERT INTO sync_state (key, value) VALUES ('schema_version', ?1)
              ON CONFLICT(key) DO UPDATE SET value = excluded.value",
@@ -469,7 +577,7 @@ CREATE TABLE trash (
 );
 ";
 
-/// Schema v8: device sync (devices.md). This machine registers as one Proton Drive
+/// Schema v8: device sync. This machine registers as one Proton Drive
 /// **Device** (a share + root folder on the main volume); `device` is a singleton
 /// row cached so we reuse the same device across restarts instead of creating a
 /// new one each run. `sync_folder` is one row per local folder the user added,
@@ -530,8 +638,8 @@ ALTER TABLE sync_folder ADD COLUMN pending_mode TEXT;
 ";
 
 /// Schema v11: writes no longer upload inside the FUSE handler. `release` stages
-/// the bytes and records the intended upload here, and a drain worker performs it
+/// the bytes and records the intended upload here, and a drain worker performs it.
-/// (offline.md Phase 3). The row outlives the process, so a write survives both a
+/// The row outlives the process, so a write survives both a
 /// dead network and a restart.
 ///
 /// `blob_path` points into the content cache's `staging/` dir and `meta_json` is
@@ -558,7 +666,7 @@ CREATE INDEX pending_op_uid ON pending_op(uid);
 
 /// Schema v12: `pending_op` also carries mutations that *create* a node, which a
 /// revision op never had to describe — it always addressed a node the server had
-/// already minted a uid for (offline.md Phase 3b).
+/// already minted a uid for.
 ///
 /// An offline `create`/`mkdir` cannot get a real uid, so the node is invented
 /// locally under a `local~<uuid>` placeholder and the op records where it goes
@@ -948,7 +1056,7 @@ ALTER TABLE pending_op ADD COLUMN access_deferred_since INTEGER NOT NULL DEFAULT
 /// as the last sync and left the file the same length — a fixed-size record
 /// rewritten, an image re-exported, a database page updated in place — read as
 /// *unchanged* and was never uploaded. The remote copy silently stayed at the
-/// older content until something else about the file moved (bugs.md B25).
+/// older content until something else about the file moved (`docs/BUGS.md` B25).
 ///
 /// Nullable rather than a converted `local_mtime * 1_000_000_000`: the
 /// nanosecond part of an existing baseline is genuinely unknown, and inventing
@@ -1059,3 +1167,166 @@ ALTER TABLE photos ADD COLUMN similar_hash INTEGER;
 const MIGRATION_V35: &str = "
 ALTER TABLE trash ADD COLUMN trashed_at INTEGER;
 ";
+
+/// Schema v36: every node row has a local id (`lid`); see
+/// docs/ARCHITECTURE.md §2.
+///
+/// The `uid` was the row's key, so a node had no identity until Drive minted
+/// one, and a create that landed moved its row to a new key. The `lid` is given
+/// when the row is first written and never changes or comes back, which is what
+/// `AUTOINCREMENT` adds over a plain rowid. It takes the old rowid, so the
+/// search index, keyed by rowid since v15, stays valid. The `uid` becomes
+/// nullable for a node that is not on Drive yet.
+const MIGRATION_V36: &str = "
+CREATE TABLE nodes_v36 (
+  lid           INTEGER PRIMARY KEY AUTOINCREMENT,
+  uid           TEXT UNIQUE,
+  parent_uid    TEXT,
+  name          TEXT NOT NULL,
+  is_dir        INTEGER NOT NULL,
+  size          INTEGER,
+  mtime         INTEGER NOT NULL,
+  revision_hash TEXT,
+  trashed       INTEGER NOT NULL DEFAULT 0,
+  node_json     TEXT,
+  listed        INTEGER NOT NULL DEFAULT 0,
+  path          TEXT
+);
+INSERT INTO nodes_v36
+  (lid, uid, parent_uid, name, is_dir, size, mtime, revision_hash, trashed, node_json, listed,
+   path)
+  SELECT rowid, uid, parent_uid, name, is_dir, size, mtime, revision_hash, trashed, node_json,
+         listed, path
+    FROM nodes;
+DROP TABLE nodes;
+ALTER TABLE nodes_v36 RENAME TO nodes;
+CREATE INDEX idx_nodes_parent ON nodes(parent_uid);
+CREATE INDEX idx_nodes_name_nocase ON nodes(name COLLATE NOCASE);
+CREATE INDEX idx_nodes_parent_live ON nodes(parent_uid) WHERE trashed = 0;
+";
+
+/// Schema v37: a `pending_op` id is never given out twice.
+///
+/// A plain rowid is the largest one plus one, so an op queued right after the
+/// newest one was dropped took its id. The drain retires the op it is
+/// working on by id, and so deleted the new op: a trash queued over a rename
+/// on the wire was lost when the rename landed. `AUTOINCREMENT` never reuses
+/// an id. Ids are kept, as is every index.
+const MIGRATION_V37: &str = "
+CREATE TABLE pending_op_v37 (
+  id                    INTEGER PRIMARY KEY AUTOINCREMENT,
+  kind                  TEXT NOT NULL,
+  uid                   TEXT NOT NULL,
+  blob_path             TEXT,
+  meta_json             TEXT,
+  created_at            INTEGER NOT NULL,
+  attempts              INTEGER NOT NULL DEFAULT 0,
+  last_error            TEXT,
+  next_attempt_at       INTEGER NOT NULL DEFAULT 0,
+  parent_uid            TEXT,
+  name                  TEXT,
+  claimed_at            INTEGER NOT NULL DEFAULT 0,
+  access_deferred_since INTEGER NOT NULL DEFAULT 0
+);
+INSERT INTO pending_op_v37
+  (id, kind, uid, blob_path, meta_json, created_at, attempts, last_error, next_attempt_at,
+   parent_uid, name, claimed_at, access_deferred_since)
+  SELECT id, kind, uid, blob_path, meta_json, created_at, attempts, last_error,
+         next_attempt_at, parent_uid, name, claimed_at, access_deferred_since
+    FROM pending_op;
+DROP TABLE pending_op;
+ALTER TABLE pending_op_v37 RENAME TO pending_op;
+CREATE INDEX pending_op_uid ON pending_op(uid);
+CREATE INDEX pending_op_parent ON pending_op(parent_uid);
+CREATE INDEX idx_pending_op_claimed
+    ON pending_op(uid) WHERE claimed_at <> 0;
+";
+
+/// Schema v38: why Drive refused a queued op, when it did (a sync issue).
+/// `NULL` for an op that has not been refused, which is every op migrated.
+const MIGRATION_V38: &str = "
+ALTER TABLE pending_op ADD COLUMN issue TEXT;
+";
+
+/// Schema v39: a queued op names its node and its parent by local id too.
+///
+/// A create made inside a folder that had not landed named the folder by its
+/// placeholder uid, and every landing had to find and rewrite those strings.
+/// The local id stays the same when the folder lands. An op whose node has no
+/// row keeps `NULL` and is matched by uid, as before.
+const MIGRATION_V39: &str = "
+ALTER TABLE pending_op ADD COLUMN lid INTEGER;
+ALTER TABLE pending_op ADD COLUMN parent_lid INTEGER;
+UPDATE pending_op
+   SET lid = (SELECT lid FROM nodes WHERE nodes.uid = pending_op.uid),
+       parent_lid = (SELECT lid FROM nodes WHERE nodes.uid = pending_op.parent_uid);
+CREATE INDEX pending_op_lid ON pending_op(lid);
+CREATE INDEX pending_op_parent_lid ON pending_op(parent_lid);
+";
+
+/// Schema v40: a node row names its parent by local id too.
+///
+/// The local id stays when a folder made here lands and its row takes the uid
+/// Drive gave it, so a child linked by it needs no rewrite. `NULL` while the
+/// parent has no row, as `parent_uid` then names nothing either.
+const MIGRATION_V40: &str = "
+ALTER TABLE nodes ADD COLUMN parent_lid INTEGER;
+UPDATE nodes SET parent_lid = (SELECT p.lid FROM nodes p WHERE p.uid = nodes.parent_uid);
+CREATE INDEX idx_nodes_parent_lid ON nodes(parent_lid);
+";
+
+/// Schema v41: a node made on this machine goes by `local~<lid>` until it
+/// lands, a function of its row, where it used to get a `local~<ms>-<n>`
+/// placeholder. Every placeholder still stored is rewritten to its row's
+/// stand-in: the row itself and its `node_json`, its children, the ops on it
+/// or into it, and its pins. A placeholder op with no row keeps its uid and
+/// drains as before.
+const MIGRATION_V41: &str = "
+CREATE TEMP TABLE local_v41 AS
+  SELECT uid AS old, 'local~' || lid AS new, lid FROM nodes
+   WHERE uid LIKE 'local~%' AND uid <> 'local~' || lid;
+UPDATE pending_op SET uid = (SELECT new FROM local_v41 WHERE old = pending_op.uid)
+ WHERE uid IN (SELECT old FROM local_v41);
+UPDATE pending_op SET parent_uid = (SELECT new FROM local_v41 WHERE old = pending_op.parent_uid)
+ WHERE parent_uid IN (SELECT old FROM local_v41);
+UPDATE pending_op
+   SET meta_json = json_set(meta_json, '$.uid',
+         (SELECT new FROM local_v41 WHERE old = json_extract(pending_op.meta_json, '$.uid')))
+ WHERE json_valid(meta_json)
+   AND json_extract(meta_json, '$.uid') IN (SELECT old FROM local_v41);
+UPDATE pending_op
+   SET meta_json = json_set(meta_json, '$.original_parent_uid',
+         (SELECT new FROM local_v41
+           WHERE old = json_extract(pending_op.meta_json, '$.original_parent_uid')))
+ WHERE json_valid(meta_json)
+   AND json_extract(meta_json, '$.original_parent_uid') IN (SELECT old FROM local_v41);
+UPDATE pins SET uid = (SELECT new FROM local_v41 WHERE old = pins.uid)
+ WHERE uid IN (SELECT old FROM local_v41);
+UPDATE nodes
+   SET node_json = json_set(node_json, '$.parent_uid.link_id',
+         (SELECT CAST(lid AS TEXT) FROM local_v41 WHERE old = nodes.parent_uid))
+ WHERE parent_uid IN (SELECT old FROM local_v41)
+   AND json_valid(node_json)
+   AND json_extract(node_json, '$.parent_uid.volume_id') = 'local';
+UPDATE nodes SET parent_uid = (SELECT new FROM local_v41 WHERE old = nodes.parent_uid)
+ WHERE parent_uid IN (SELECT old FROM local_v41);
+UPDATE nodes
+   SET node_json = json_set(node_json, '$.uid.link_id', CAST(lid AS TEXT))
+ WHERE lid IN (SELECT lid FROM local_v41)
+   AND json_valid(node_json)
+   AND json_extract(node_json, '$.uid.volume_id') = 'local';
+UPDATE nodes SET uid = 'local~' || lid WHERE lid IN (SELECT lid FROM local_v41);
+DROP TABLE local_v41;
+";
+
+/// Schema v42: the SHA-1 of each blob a queued create sent, space-separated.
+/// A create whose answer was lost may have made its file with any of them,
+/// and the op that finds that file again may run after a restart. `NULL` for
+/// an op that has sent nothing, which is every op migrated: what the daemon
+/// that wrote it sent is not known. Likewise the parent and name each attempt
+/// was sent under, as a JSON list of pairs: a rename since then moves the op
+/// but not the file Drive may have made.
+const MIGRATION_V42: &str = "
+ALTER TABLE pending_op ADD COLUMN sent_sha1 TEXT;
+ALTER TABLE pending_op ADD COLUMN sent_to TEXT;
+";

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

@@ -56,8 +56,9 @@ pub use local::LocalFileHit;
 pub use maintenance::{DbStats, VacuumOutcome};
 pub use nodes::{PublishedSharedRoot, SearchHit, StoredNode};
 pub use ops::{
-    AttachedBlob, FAILING_ATTEMPTS, LOCAL_VOLUME, OP_CREATE, OP_MKDIR, OP_RENAME, OP_REVISION,
+    AttachedBlob, CreateLanding, CreateRetired, FAILING_ATTEMPTS, LOCAL_VOLUME, OP_CREATE,
-    OP_TRASH, PARK_EXPIRY_MS, PARK_UNTIL, PendingCounts, PendingOp, RenameMeta, op_supersedes,
+    OP_MKDIR, OP_RENAME, OP_REVISION, OP_TRASH, PARK_EXPIRY_MS, PARK_UNTIL, PendingCounts,
+    PendingOp, RenameMeta, local_lid, local_uid, op_supersedes,
 };
 pub use photos::{StoredPhoto, StoredPlace, THUMB_HAVE, THUMB_NONE, THUMB_UNKNOWN, TimelineRow};
 pub use pins::PinRow;

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

@@ -3,9 +3,11 @@
 
 use std::collections::HashSet;
 
+use rusqlite::types::Value;
 use rusqlite::{OptionalExtension, Transaction, params};
 
 use super::Db;
+use super::ops::{OP_CREATE, OP_MKDIR, OP_RENAME, local_lid, local_uid, wake_ops_waiting_for_tx};
 use crate::{Access, Result};
 use proton_drive_rs::proton_sdk::ids::{LinkId, NodeUid, VolumeId};
 use proton_drive_rs::{Node, NodeKind};
@@ -17,6 +19,8 @@ use super::utils::{
 pub struct StoredNode {
     pub node: Node,
     pub listed: bool,
+    /// The row's local id ([`Db::lid_of`]).
+    pub lid: i64,
 }
 
 /// One full-text search match: the stored [`Node`] plus its mountpoint-relative
@@ -62,12 +66,13 @@ impl Db {
     /// snapshot while offline, including after a live event expired its TTL.
     pub fn visible_children(&self, parent: &NodeUid) -> Result<Vec<Node>> {
         let conn = self.read();
-        let mut stmt = conn.prepare(
+        let (key, parent) = parent_key(&conn, &parent.to_string())?;
-            "SELECT node_json FROM nodes
+        let mut stmt = conn.prepare(&format!(
-              WHERE parent_uid = ?1 AND trashed = 0 AND node_json IS NOT NULL
+            "SELECT {NODE_NOW} FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
-              ORDER BY name, uid",
+              WHERE n.{key} = ?1 AND n.trashed = 0 AND n.node_json IS NOT NULL
-        )?;
+              ORDER BY n.name, n.uid"
-        let rows = stmt.query_map([parent.to_string()], |row| row.get::<_, String>(0))?;
+        ))?;
+        let rows = stmt.query_map([parent], |row| row.get::<_, String>(0))?;
         let mut nodes = Vec::new();
         for row in rows {
             nodes.push(serde_json::from_str(&row?)?);
@@ -264,10 +269,25 @@ impl Db {
     /// resolve its shared-tree access. Removing the op first could resurrect
     /// that row after a crash; removing the row first could strand a now
     /// unauthorizable op. One transaction closes both windows.
-    pub fn complete_trash_op(&self, op_id: i64, uid: &NodeUid) -> Result<()> {
+    ///
+    /// An op that found the name still held by this trash failed with a
+    /// backoff, and the name is free now. It is made due at once
+    /// ([`Db::wake_ops_waiting_for`]).
+    ///
+    /// Returns the staged blob of the create the trash withdrew, if it kept
+    /// one, for the caller to discard.
+    pub fn complete_trash_op(&self, op_id: i64, uid: &NodeUid) -> Result<Option<String>> {
         let uid = uid.to_string();
         let mut conn = self.conn.lock();
         let tx = conn.transaction()?;
+        let (name, blob): (Option<String>, Option<String>) = tx
+            .query_row(
+                "SELECT name, blob_path FROM pending_op WHERE id = ?1",
+                params![op_id],
+                |row| Ok((row.get(0)?, row.get(1)?)),
+            )
+            .optional()?
+            .unwrap_or_default();
         let rowid: Option<i64> = tx
             .query_row(
                 "SELECT rowid FROM nodes WHERE uid = ?1",
@@ -280,17 +300,23 @@ impl Db {
             tx.execute("DELETE FROM nodes_fts WHERE rowid = ?1", params![rowid])?;
         }
         tx.execute("DELETE FROM pending_op WHERE id = ?1", params![op_id])?;
+        if let Some(name) = name {
+            wake_ops_waiting_for_tx(&tx, &name)?;
+        }
         tx.commit()?;
-        Ok(())
+        Ok(blob)
     }
 
     /// Check if a folder node has any non-trashed children in the database.
     pub fn has_children(&self, parent_uid: &NodeUid) -> Result<bool> {
-        let uid_str = parent_uid.to_string();
         let conn = self.read();
+        let (key, parent) = parent_key(&conn, &parent_uid.to_string())?;
         let count: i64 = conn.query_row(
-            "SELECT COUNT(*) FROM nodes WHERE parent_uid = ?1 AND trashed = 0",
+            &format!(
-            params![uid_str],
+                "SELECT COUNT(*) FROM nodes
+                 WHERE {key} = ?1 AND trashed = 0 AND node_json IS NOT NULL"
+            ),
+            params![parent],
             |row| row.get(0),
         )?;
         Ok(count > 0)
@@ -305,9 +331,11 @@ impl Db {
     pub fn node_path(&self, uid: &str) -> Result<Option<String>> {
         let conn = self.read();
         let exists: Option<i64> = conn
-            .query_row("SELECT 1 FROM nodes WHERE uid = ?1", params![uid], |r| {
+            .query_row(
-                r.get(0)
+                "SELECT 1 FROM nodes WHERE uid = ?1 AND node_json IS NOT NULL",
-            })
+                params![uid],
+                |r| r.get(0),
+            )
             .optional()?;
         if exists.is_none() {
             return Ok(None);
@@ -325,11 +353,11 @@ impl Db {
     pub fn path_relative_to(&self, ancestor_uid: &str, uid: &str) -> Result<Option<String>> {
         let conn = self.read();
         let mut stmt = conn.prepare(
-            "WITH RECURSIVE anc(uid, parent_uid, name, depth) AS (
+            "WITH RECURSIVE anc(uid, parent_lid, name, depth) AS (
-               SELECT uid, parent_uid, name, 0 FROM nodes WHERE uid = ?1
+               SELECT uid, parent_lid, name, 0 FROM nodes WHERE uid = ?1
                UNION ALL
-               SELECT n.uid, n.parent_uid, n.name, anc.depth + 1
+               SELECT n.uid, n.parent_lid, n.name, anc.depth + 1
-               FROM nodes n JOIN anc ON n.uid = anc.parent_uid
+               FROM nodes n JOIN anc ON n.lid = anc.parent_lid
                WHERE anc.depth < 1024
              )
              SELECT uid, name FROM anc ORDER BY depth",
@@ -378,12 +406,13 @@ impl Db {
         let conn = self.read();
         let rows: Vec<HitRow> = if query.chars().count() < TRIGRAM_MIN {
             let pat = format!("%{}%", like_escape(query));
-            let mut stmt = conn.prepare(
+            let mut stmt = conn.prepare(&format!(
-                "SELECT node_json, uid, path FROM nodes
+                "SELECT {NODE_NOW}, n.uid, n.path
-                 WHERE name LIKE ?1 ESCAPE '\\' AND trashed = 0 AND node_json IS NOT NULL
+                 FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
-                   AND (?3 IS NULL OR path IS NULL OR path LIKE ?3 ESCAPE '\\')
+                 WHERE n.name LIKE ?1 ESCAPE '\\' AND n.trashed = 0 AND n.node_json IS NOT NULL
-                 ORDER BY name LIMIT ?2",
+                   AND (?3 IS NULL OR n.path IS NULL OR n.path LIKE ?3 ESCAPE '\\')
-            )?;
+                 ORDER BY n.name LIMIT ?2"
+            ))?;
             collect_hits(stmt.query_map(params![pat, limit as i64, scope_pat], hit_row)?)?
         } else {
             // Escape double quotes and quote each term, then combine with AND so
@@ -393,13 +422,14 @@ impl Db {
                 .map(|word| format!("\"{}\"", word.replace('"', "\"\"")))
                 .collect::<Vec<_>>()
                 .join(" AND ");
-            let mut stmt = conn.prepare(
+            let mut stmt = conn.prepare(&format!(
-                "SELECT n.node_json, n.uid, n.path
+                "SELECT {NODE_NOW}, n.uid, n.path
                  FROM nodes_fts f JOIN nodes n ON n.rowid = f.rowid
+                 LEFT JOIN nodes p ON p.lid = n.parent_lid
                  WHERE f.name MATCH ?1 AND n.trashed = 0 AND n.node_json IS NOT NULL
                    AND (?3 IS NULL OR n.path IS NULL OR n.path LIKE ?3 ESCAPE '\\')
-                 ORDER BY f.rank LIMIT ?2",
+                 ORDER BY f.rank LIMIT ?2"
-            )?;
+            ))?;
             collect_hits(stmt.query_map(params![phrase, limit as i64, scope_pat], hit_row)?)?
         };
 
@@ -436,20 +466,22 @@ impl Db {
         let lane_limit = limit.div_ceil(2);
         let mut rows: Vec<HitRow> = if terms.is_empty() {
             let pat = format!("%{}%", like_escape(query));
-            let mut stmt = conn.prepare(
+            let mut stmt = conn.prepare(&format!(
-                "SELECT node_json, uid, path FROM nodes
+                "SELECT {NODE_NOW}, n.uid, n.path
-                 WHERE name LIKE ?1 ESCAPE '\\' AND trashed = 0 AND node_json IS NOT NULL
+                 FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
-                 ORDER BY name LIMIT ?2",
+                 WHERE n.name LIKE ?1 ESCAPE '\\' AND n.trashed = 0 AND n.node_json IS NOT NULL
-            )?;
+                 ORDER BY n.name LIMIT ?2"
+            ))?;
             collect_hits(stmt.query_map(params![pat, limit as i64], hit_row)?)?
         } else {
             let expression = terms.join(" OR ");
-            let mut stmt = conn.prepare(
+            let mut stmt = conn.prepare(&format!(
-                "SELECT n.node_json, n.uid, n.path
+                "SELECT {NODE_NOW}, n.uid, n.path
                    FROM nodes_fts f JOIN nodes n ON n.rowid = f.rowid
+                   LEFT JOIN nodes p ON p.lid = n.parent_lid
                   WHERE nodes_fts MATCH ?1 AND n.trashed = 0 AND n.node_json IS NOT NULL
-                  ORDER BY f.rank LIMIT ?2",
+                  ORDER BY f.rank LIMIT ?2"
-            )?;
+            ))?;
             collect_hits(stmt.query_map(params![expression, lane_limit as i64], hit_row)?)?
         };
         // Trigram rank does not know that a name *starts* with the query, and a
@@ -459,12 +491,13 @@ impl Db {
         if !terms.is_empty()
             && let Some(first) = query.chars().next()
         {
-            let mut stmt = conn.prepare(
+            let mut stmt = conn.prepare(&format!(
-                "SELECT node_json, uid, path FROM nodes
+                "SELECT {NODE_NOW}, n.uid, n.path
-                 WHERE name COLLATE NOCASE LIKE ?1 ESCAPE '\\'
+                 FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
-                   AND trashed = 0 AND node_json IS NOT NULL
+                 WHERE n.name COLLATE NOCASE LIKE ?1 ESCAPE '\\'
-                 ORDER BY name COLLATE NOCASE LIMIT ?2",
+                   AND n.trashed = 0 AND n.node_json IS NOT NULL
-            )?;
+                 ORDER BY n.name COLLATE NOCASE LIMIT ?2"
+            ))?;
             let mut extra = Vec::new();
             for pattern in [
                 format!("{}%", like_escape(query)),
@@ -500,40 +533,50 @@ impl Db {
     /// re-enumerates from the remote on next access.
     pub fn set_listed(&self, uid: &NodeUid, listed: bool) -> Result<()> {
         let conn = self.conn.lock();
+        let (key, uid) = row_key(&uid.to_string());
         conn.execute(
-            "UPDATE nodes SET listed = ?2 WHERE uid = ?1",
+            &format!("UPDATE nodes SET listed = ?2 WHERE {key} = ?1"),
-            params![uid.to_string(), listed as i64],
+            params![uid, listed as i64],
         )?;
         Ok(())
     }
 
     /// Load every persisted node for cold-start hydration of the `State` maps.
+    ///
+    /// Each node names its parent as the parent's row has it now, found by
+    /// local id: a folder that landed has its new uid there, while the node
+    /// stored below it may still hold the placeholder.
     pub fn load_all(&self) -> Result<Vec<StoredNode>> {
         let conn = self.read();
-        let mut stmt =
+        let mut stmt = conn.prepare(&format!(
-            conn.prepare("SELECT node_json, listed FROM nodes WHERE node_json IS NOT NULL")?;
+            "SELECT {NODE_NOW}, n.listed, n.lid
+             FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
+             WHERE n.node_json IS NOT NULL"
+        ))?;
         let rows = stmt.query_map([], |row| {
             let json: String = row.get(0)?;
             let listed: i64 = row.get(1)?;
-            Ok((json, listed != 0))
+            Ok((json, listed != 0, row.get(2)?))
         })?;
         let mut out = Vec::new();
         for row in rows {
-            let (json, listed) = row?;
+            let (json, listed, lid) = row?;
             let node: Node = serde_json::from_str(&json)?;
-            out.push(StoredNode { node, listed });
+            out.push(StoredNode { node, listed, lid });
         }
         Ok(out)
     }
 
     /// Load one persisted node back by uid. Used to recover the My Files root
-    /// when the API is unreachable, so the mount can still serve the cached tree
+    /// when the API is unreachable, so the mount can still serve the cached tree.
-    /// (offline.md Phase 1).
     pub fn node_by_uid(&self, uid: &str) -> Result<Option<Node>> {
         let conn = self.read();
         let json: Option<String> = conn
             .query_row(
-                "SELECT node_json FROM nodes WHERE uid = ?1 AND node_json IS NOT NULL",
+                &format!(
+                    "SELECT {NODE_NOW} FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
+                     WHERE n.uid = ?1 AND n.node_json IS NOT NULL"
+                ),
                 params![uid],
                 |r| r.get(0),
             )
@@ -544,15 +587,118 @@ impl Db {
         }
     }
 
+    /// The uid of the node with local id `lid`: `None` when it has no row, or
+    /// is not on Drive yet.
+    pub fn uid_of_lid(&self, lid: i64) -> Result<Option<String>> {
+        let conn = self.read();
+        Ok(conn
+            .query_row("SELECT uid FROM nodes WHERE lid = ?1", params![lid], |r| {
+                r.get(0)
+            })
+            .optional()?
+            .flatten())
+    }
+
+    /// The local id of the node stored under `uid`, or `None` when it has no
+    /// row. It stays the same for as long as the row exists, including when a
+    /// create lands and the row takes the uid Drive gave it: a node made on
+    /// this machine is found by its stand-in ([`local_uid`]) before and after.
+    pub fn lid_of(&self, uid: &str) -> Result<Option<i64>> {
+        node_lid(&self.read(), uid)
+    }
+
+    /// The local id of each node, in order, giving a row to each that has none.
+    ///
+    /// A new row is only a stub: it has no `node_json`, so no listing or search
+    /// returns it until the node is upserted, which the caller still owes. That
+    /// keeps this cheap enough to call with the inode lock held, which is
+    /// where an inode number is first needed.
+    pub fn lids_for(&self, nodes: &[&Node]) -> Result<Vec<i64>> {
+        let mut conn = self.conn.lock();
+        let tx = conn.transaction()?;
+        let mut lids = Vec::with_capacity(nodes.len());
+        {
+            let mut known = tx.prepare_cached("SELECT lid FROM nodes WHERE uid = ?1")?;
+            let mut stub = tx.prepare_cached(
+                "INSERT INTO nodes (uid, parent_uid, name, is_dir, mtime, trashed, parent_lid)
+                 VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7)",
+            )?;
+            for node in nodes {
+                let uid = node.uid.to_string();
+                let lid = match known.query_row(params![uid], |r| r.get(0)).optional()? {
+                    Some(lid) => lid,
+                    None => {
+                        let parent = node.parent_uid.as_ref().map(ToString::to_string);
+                        let parent_lid = match &parent {
+                            Some(parent) => node_lid(&tx, parent)?,
+                            None => None,
+                        };
+                        stub.execute(params![
+                            uid,
+                            parent,
+                            node.name,
+                            node.is_folder() as i64,
+                            node.modification_time,
+                            node.trashed as i64,
+                            parent_lid,
+                        ])?;
+                        let lid = tx.last_insert_rowid();
+                        adopt_children_tx(&tx, &uid, lid)?;
+                        lid
+                    }
+                };
+                lids.push(lid);
+            }
+        }
+        tx.commit()?;
+        Ok(lids)
+    }
+
+    /// Give a node being made on this machine its row under `parent_uid`, and
+    /// return its local id. The row goes by [`local_uid`] of that id until
+    /// the node lands.
+    ///
+    /// Like [`Db::lids_for`], only a stub: the caller upserts the node.
+    pub fn add_local_row(
+        &self,
+        parent_uid: &str,
+        name: &str,
+        is_dir: bool,
+        mtime: i64,
+    ) -> Result<i64> {
+        let mut conn = self.conn.lock();
+        let tx = conn.transaction()?;
+        tx.execute(
+            "INSERT INTO nodes (uid, parent_uid, name, is_dir, mtime, trashed, parent_lid)
+             VALUES (NULL, ?1, ?2, ?3, ?4, 0,
+                     COALESCE(?5, (SELECT lid FROM nodes WHERE uid = ?1)))",
+            params![
+                parent_uid,
+                name,
+                is_dir as i64,
+                mtime,
+                local_lid(parent_uid)
+            ],
+        )?;
+        let lid = tx.last_insert_rowid();
+        tx.execute(
+            "UPDATE nodes SET uid = ?2 WHERE lid = ?1",
+            params![lid, local_uid(lid)],
+        )?;
+        tx.commit()?;
+        Ok(lid)
+    }
+
     /// Read the persisted incremental-sync cursor (a `DriveEventId`), if any.
     /// The daemon resumes from this on restart instead of reseeding to the
     /// server head, so changes made while unmounted are still applied (P2).
     pub fn children_if_listed(&self, parent: &NodeUid) -> Result<Option<Vec<Node>>> {
         let conn = self.read();
+        let (key, folder) = row_key(&parent.to_string());
         let listed: Option<i64> = conn
             .query_row(
-                "SELECT listed FROM nodes WHERE uid = ?1",
+                &format!("SELECT listed FROM nodes WHERE {key} = ?1"),
-                params![parent.to_string()],
+                params![folder],
                 |r| r.get(0),
             )
             .optional()?;
@@ -568,11 +714,12 @@ impl Db {
     /// had: a listing dropped as stale may miss or keep a child.
     pub fn known_children(&self, parent: &NodeUid) -> Result<Vec<Node>> {
         let conn = self.read();
-        let mut stmt = conn.prepare(
+        let (key, parent) = parent_key(&conn, &parent.to_string())?;
-            "SELECT node_json FROM nodes
+        let mut stmt = conn.prepare(&format!(
-             WHERE parent_uid = ?1 AND node_json IS NOT NULL AND trashed = 0",
+            "SELECT {NODE_NOW} FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
-        )?;
+             WHERE n.{key} = ?1 AND n.node_json IS NOT NULL AND n.trashed = 0"
-        let rows = stmt.query_map(params![parent.to_string()], |r| r.get::<_, String>(0))?;
+        ))?;
+        let rows = stmt.query_map(params![parent], |r| r.get::<_, String>(0))?;
         let mut out = Vec::new();
         for json in rows {
             out.push(serde_json::from_str(&json?)?);
@@ -580,6 +727,40 @@ impl Db {
         Ok(out)
     }
 
+    /// What a queued change does to `parent`'s listing, which Drive does not
+    /// show until it lands: the children made or moved in by a queued create,
+    /// mkdir or rename, as the DB holds them, and the nodes a queued rename
+    /// moves elsewhere.
+    ///
+    /// A listing read from Drive is laid over with these, or a folder listed
+    /// while a create in it is queued, after a restart say, loses the file
+    /// until the create lands (`docs/BUGS.md` B132).
+    pub fn queued_children(&self, parent: &NodeUid) -> Result<(Vec<Node>, HashSet<String>)> {
+        let conn = self.read();
+        let (key, parent) = parent_key(&conn, &parent.to_string())?;
+        let mut stmt = conn.prepare(&format!(
+            "SELECT {NODE_NOW} FROM nodes n LEFT JOIN nodes p ON p.lid = n.parent_lid
+             WHERE n.{key} = ?1 AND n.node_json IS NOT NULL AND n.trashed = 0
+               AND EXISTS (SELECT 1 FROM pending_op o
+                           WHERE (o.lid = n.lid OR o.uid = n.uid) AND o.kind IN (?2, ?3, ?4))"
+        ))?;
+        let rows = stmt.query_map(params![parent, OP_CREATE, OP_MKDIR, OP_RENAME], |r| {
+            r.get::<_, String>(0)
+        })?;
+        let mut here = Vec::new();
+        for json in rows {
+            here.push(serde_json::from_str(&json?)?);
+        }
+        let mut stmt = conn.prepare(&format!(
+            "SELECT DISTINCT n.uid FROM pending_op p JOIN nodes n ON n.lid = p.lid OR n.uid = p.uid
+             WHERE p.kind = ?2 AND n.{key} IS NOT ?1"
+        ))?;
+        let gone = stmt
+            .query_map(params![parent, OP_RENAME], |r| r.get::<_, String>(0))?
+            .collect::<std::result::Result<HashSet<_>, _>>()?;
+        Ok((here, gone))
+    }
+
     // --- Content-cache LRU index (P4) -------------------------------------
     //
     // Replaces the per-eviction `read_dir` scans in `ContentCache`. Each cached
@@ -599,9 +780,157 @@ struct PriorRow {
     trashed: bool,
 }
 
+/// [`Db::lid_of`] on `conn`, which may be a transaction.
+pub(super) fn node_lid(conn: &rusqlite::Connection, uid: &str) -> Result<Option<i64>> {
+    let row = match local_lid(uid) {
+        Some(lid) => conn.query_row("SELECT lid FROM nodes WHERE lid = ?1", params![lid], |r| {
+            r.get(0)
+        }),
+        None => conn.query_row("SELECT lid FROM nodes WHERE uid = ?1", params![uid], |r| {
+            r.get(0)
+        }),
+    };
+    Ok(row.optional()?)
+}
+
+/// The column and value that find `uid`'s own row. A stand-in is found by its
+/// local id: a create that lands gives the row the uid Drive made before the
+/// tree has it, and the tree asks by the stand-in until then (`docs/BUGS.md`
+/// B177).
+fn row_key(uid: &str) -> (&'static str, Value) {
+    match local_lid(uid) {
+        Some(lid) => ("lid", Value::Integer(lid)),
+        None => ("uid", Value::Text(uid.to_owned())),
+    }
+}
+
+/// The column and value a row names `parent` by: its local id when it has a
+/// row, which the children keep when it lands, or its uid when it has none,
+/// as a device folder's root does.
+fn parent_key(conn: &rusqlite::Connection, parent: &str) -> Result<(&'static str, Value)> {
+    Ok(match node_lid(conn, parent)? {
+        Some(lid) => ("parent_lid", Value::Integer(lid)),
+        None => ("parent_uid", Value::Text(parent.to_owned())),
+    })
+}
+
+/// `n.node_json` naming its parent as the parent's row `p`, joined by
+/// `n.parent_lid`, has it now. A folder that lands takes its real uid in its
+/// own row only, so a node stored below it still names the stand-in.
+const NODE_NOW: &str = "CASE WHEN p.uid IS NULL OR p.uid = n.parent_uid THEN n.node_json
+     ELSE json_set(n.node_json, '$.parent_uid', json_object(
+            'volume_id', substr(p.uid, 1, instr(p.uid, '~') - 1),
+            'link_id', substr(p.uid, instr(p.uid, '~') + 1))) END";
+
+/// Hand a drained placeholder's row to the real uid it landed as.
+///
+/// Nothing else is rewritten. The rows below it and the ops made inside it
+/// name it by its local id, which stays; what reads them for a uid takes the
+/// one the row has now ([`NODE_NOW`], `PARENT_NOW` in `ops.rs`).
+///
+/// Dropping the placeholder row and waiting for the server's copy of the real
+/// node left a window with no row for either uid. A queued child drained in
+/// that window found no authority for its parent, re-read it over the network
+/// and was deferred five seconds behind a folder that had just landed
+/// (`docs/BUGS.md` B120). The placeholder's own node, readdressed, stands in
+/// until the server's copy is upserted over it. A row the real uid already
+/// has is newer than the placeholder, so its node is kept, under the
+/// placeholder's `lid`: the node was known by that one first.
+pub(super) fn adopt_placeholder_row_tx(
+    tx: &Transaction<'_>,
+    local: &str,
+    real: &str,
+) -> Result<()> {
+    // A folder pinned before it landed stays pinned: the pin keyed by the
+    // placeholder was dropped with it (`docs/BUGS.md` B148).
+    tx.execute(
+        "UPDATE OR IGNORE pins SET uid = ?2 WHERE uid = ?1",
+        params![local, real],
+    )?;
+    tx.execute("DELETE FROM pins WHERE uid = ?1", params![local])?;
+    let row: Option<(i64, Option<String>)> = tx
+        .query_row(
+            "SELECT lid, node_json FROM nodes WHERE uid = ?1",
+            params![local],
+            |row| Ok((row.get(0)?, row.get(1)?)),
+        )
+        .optional()?;
+    // Ops queued before schema 39 have no `parent_lid`, nor do ops made
+    // under a placeholder that never had a row.
+    tx.execute(
+        "UPDATE pending_op SET parent_uid = ?2 WHERE parent_lid IS NULL AND parent_uid = ?1",
+        params![local, real],
+    )?;
+    let Some((lid, json)) = row else {
+        return Ok(());
+    };
+    let known: Option<(i64, Option<String>)> = tx
+        .query_row(
+            "SELECT lid, node_json FROM nodes WHERE uid = ?1",
+            params![real],
+            |row| Ok((row.get(0)?, row.get(1)?)),
+        )
+        .optional()?;
+    if let Some((known_lid, _)) = known {
+        // Ops queued against the row Drive listed now name the landing one.
+        tx.execute(
+            "UPDATE pending_op SET lid = ?2 WHERE lid = ?1",
+            params![known_lid, lid],
+        )?;
+        tx.execute(
+            "UPDATE pending_op SET parent_lid = ?2 WHERE parent_lid = ?1",
+            params![known_lid, lid],
+        )?;
+        tx.execute(
+            "UPDATE nodes SET parent_lid = ?2 WHERE parent_lid = ?1",
+            params![known_lid, lid],
+        )?;
+        tx.execute("DELETE FROM nodes WHERE lid = ?1", params![known_lid])?;
+        tx.execute("DELETE FROM nodes_fts WHERE rowid = ?1", params![known_lid])?;
+    }
+    tx.execute(
+        "UPDATE nodes SET uid = ?2 WHERE lid = ?1",
+        params![lid, real],
+    )?;
+    let json = known.and_then(|(_, known_json)| known_json).or(json);
+    let (Some(json), Some(real)) = (json, parse_node_uid(real)) else {
+        return Ok(());
+    };
+    let mut node: Node = serde_json::from_str(&json)?;
+    node.uid = real;
+    upsert_node_tx(tx, &node)
+}
+
+/// Link the rows that name `uid` as their parent to its new row `lid`: they
+/// were stored before it, or under a row of the same uid since dropped.
+fn adopt_children_tx(tx: &Transaction<'_>, uid: &str, lid: i64) -> Result<()> {
+    tx.execute(
+        "UPDATE nodes SET parent_lid = ?2 WHERE parent_uid = ?1 AND parent_lid IS NOT ?2",
+        params![uid, lid],
+    )?;
+    Ok(())
+}
+
 fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
-    let json = serde_json::to_string(node)?;
     let uid = node.uid.to_string();
+    // A node written under its stand-in after it landed is its row, which has
+    // the uid Drive gave it by now: written under the stand-in, it would bring
+    // the placeholder row back beside it.
+    if let Some(lid) = local_lid(&uid) {
+        let landed: Option<String> = tx
+            .query_row(
+                "SELECT uid FROM nodes WHERE lid = ?1 AND uid IS NOT ?2",
+                params![lid, uid],
+                |row| row.get(0),
+            )
+            .optional()?;
+        if let Some(real) = landed.as_deref().and_then(parse_node_uid) {
+            let mut node = node.clone();
+            node.uid = real;
+            return upsert_node_tx(tx, &node);
+        }
+    }
+    let json = serde_json::to_string(node)?;
     let parent_uid = node.parent_uid.as_ref().map(|u| u.to_string());
 
     let prior: Option<PriorRow> = tx
@@ -623,26 +952,34 @@ fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
     // where resolving it from scratch is a recursive walk to the root. A node
     // whose parent is not cached (a device folder's root lives in `device`, never
     // in `nodes`) starts a path of its own, which is what the walk did too.
-    let path = match &parent_uid {
+    let (parent_lid, path) = match &parent_uid {
-        None => String::new(),
+        None => (None, String::new()),
         Some(parent) => {
-            let parent_path: Option<Option<String>> = tx
+            let parent_row: Option<(i64, Option<String>)> = match node_lid(tx, parent)? {
-                .query_row(
+                Some(lid) => tx
-                    "SELECT path FROM nodes WHERE uid = ?1",
+                    .query_row(
-                    params![parent],
+                        "SELECT lid, path FROM nodes WHERE lid = ?1",
-                    |row| row.get(0),
+                        params![lid],
-                )
+                        |row| Ok((row.get(0)?, row.get(1)?)),
-                .optional()?;
+                    )
-            join_path(parent_path.flatten().as_deref().unwrap_or(""), &node.name)
+                    .optional()?,
+                None => None,
+            };
+            let (lid, parent_path) = parent_row.unzip();
+            (
+                lid,
+                join_path(parent_path.flatten().as_deref().unwrap_or(""), &node.name),
+            )
         }
     };
 
     tx.execute(
         "INSERT INTO nodes
-           (uid, parent_uid, name, is_dir, size, mtime, trashed, node_json, path)
+           (uid, parent_uid, name, is_dir, size, mtime, trashed, node_json, path, parent_lid)
-         VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9)
+         VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9, ?10)
          ON CONFLICT(uid) DO UPDATE SET
            parent_uid = excluded.parent_uid,
+           parent_lid = excluded.parent_lid,
            name       = excluded.name,
            is_dir     = excluded.is_dir,
            size       = excluded.size,
@@ -660,6 +997,7 @@ fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
             node.trashed as i64,
             json,
             path,
+            parent_lid,
         ],
     )?;
     let rowid: i64 = tx.query_row(
@@ -667,6 +1005,9 @@ fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
         params![uid],
         |row| row.get(0),
     )?;
+    if prior.is_none() {
+        adopt_children_tx(tx, &uid, rowid)?;
+    }
 
     // FTS5 has no UPSERT, so the node's own row is always replaced.
     let indexable = node_is_indexable_tx(tx, &uid)?;
@@ -689,7 +1030,7 @@ fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
             || prior.trashed != node.trashed
     });
     if node.is_folder() && subtree_moved {
-        reindex_subtree_tx(tx, &uid, &path, indexable)?;
+        reindex_subtree_tx(tx, rowid, &path, indexable)?;
     }
     Ok(())
 }
@@ -710,22 +1051,22 @@ fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
 /// this deep.
 fn reindex_subtree_tx(
     tx: &Transaction<'_>,
-    folder: &str,
+    folder: i64,
     folder_path: &str,
     folder_indexable: bool,
 ) -> Result<()> {
     let descendants: Vec<(i64, String, bool)> = {
         let mut stmt = tx.prepare(
-            "WITH RECURSIVE sub(rowid, uid, name, path, blocked, depth) AS (
+            "WITH RECURSIVE sub(rowid, name, path, blocked, depth) AS (
-               SELECT n.rowid, n.uid, n.name,
+               SELECT n.rowid, n.name,
                       CASE WHEN ?2 = '' THEN n.name ELSE ?2 || '/' || n.name END,
                       n.trashed, 0
-                 FROM nodes n WHERE n.parent_uid = ?1
+                 FROM nodes n WHERE n.parent_lid = ?1
                UNION ALL
-               SELECT n.rowid, n.uid, n.name,
+               SELECT n.rowid, n.name,
                       sub.path || '/' || n.name,
                       MAX(sub.blocked, n.trashed), sub.depth + 1
-                 FROM nodes n JOIN sub ON n.parent_uid = sub.uid
+                 FROM nodes n JOIN sub ON n.parent_lid = sub.rowid
                 WHERE sub.depth < 256
              )
              SELECT rowid, path, blocked FROM sub",
@@ -750,8 +1091,10 @@ fn reindex_subtree_tx(
     let mut set_path = tx.prepare("UPDATE nodes SET path = ?2 WHERE rowid = ?1")?;
     let mut unindex = tx.prepare("DELETE FROM nodes_fts WHERE rowid = ?1")?;
     let mut index = tx.prepare(
+        // Not a stub row (`Db::lids_for`): it is indexed when its node is
+        // written.
         "INSERT INTO nodes_fts (rowid, name, path)
-         SELECT rowid, name, ?2 FROM nodes WHERE rowid = ?1",
+         SELECT rowid, name, ?2 FROM nodes WHERE rowid = ?1 AND node_json IS NOT NULL",
     )?;
     for (rowid, path, blocked) in descendants {
         set_path.execute(params![rowid, path])?;
@@ -764,7 +1107,8 @@ fn reindex_subtree_tx(
 }
 
 fn direct_child_uids_tx(tx: &Transaction<'_>, parent: &str) -> Result<Vec<String>> {
-    let mut stmt = tx.prepare("SELECT uid FROM nodes WHERE parent_uid = ?1")?;
+    let (key, parent) = parent_key(tx, parent)?;
+    let mut stmt = tx.prepare(&format!("SELECT uid FROM nodes WHERE {key} = ?1"))?;
     let rows = stmt.query_map([parent], |row| row.get::<_, String>(0))?;
     let mut uids = Vec::new();
     for row in rows {
@@ -789,14 +1133,14 @@ fn direct_child_uids_tx(tx: &Transaction<'_>, parent: &str) -> Result<Vec<String
 /// ends at one whose parent is a row we have already visited.
 fn node_is_indexable_tx(tx: &Transaction<'_>, uid: &str) -> Result<bool> {
     let indexable: i64 = tx.query_row(
-        "WITH RECURSIVE ancestors(uid, parent_uid, trashed, depth, path) AS (
+        "WITH RECURSIVE ancestors(lid, parent_lid, trashed, depth, path) AS (
-           SELECT uid, parent_uid, trashed, 0, char(31) || uid || char(31)
+           SELECT lid, parent_lid, trashed, 0, ',' || lid || ','
              FROM nodes WHERE uid = ?1
            UNION ALL
-           SELECT n.uid, n.parent_uid, n.trashed, a.depth + 1,
+           SELECT n.lid, n.parent_lid, n.trashed, a.depth + 1,
-                  a.path || n.uid || char(31)
+                  a.path || n.lid || ','
-             FROM ancestors a JOIN nodes n ON n.uid = a.parent_uid
+             FROM ancestors a JOIN nodes n ON n.lid = a.parent_lid
-            WHERE instr(a.path, char(31) || n.uid || char(31)) = 0
+            WHERE instr(a.path, ',' || n.lid || ',') = 0
          )
          SELECT CASE
            WHEN COUNT(*) = 0 THEN 0
@@ -804,8 +1148,7 @@ fn node_is_indexable_tx(tx: &Transaction<'_>, uid: &str) -> Result<bool> {
            WHEN EXISTS (
              SELECT 1 FROM ancestors a
               WHERE a.depth = (SELECT MAX(depth) FROM ancestors)
-                AND a.parent_uid IS NOT NULL
+                AND EXISTS (SELECT 1 FROM nodes p WHERE p.lid = a.parent_lid)
-                AND EXISTS (SELECT 1 FROM nodes p WHERE p.uid = a.parent_uid)
            ) THEN 0
            ELSE 1
          END
@@ -823,7 +1166,7 @@ fn tombstone_subtree_tx(tx: &Transaction<'_>, root_uid: &str) -> Result<()> {
                SELECT rowid, uid, node_json FROM nodes WHERE uid = ?1
                UNION
                SELECT n.rowid, n.uid, n.node_json FROM nodes n
-                 JOIN subtree s ON n.parent_uid = s.uid
+                 JOIN subtree s ON n.parent_lid = s.rowid
              )
              SELECT rowid, uid, node_json FROM subtree",
         )?;

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

@@ -64,11 +64,11 @@ impl Db {
     }
 
     /// Whether `uid` is pinned — directly, or because a strict ancestor folder
-    /// is pinned recursively. The ancestor check walks `parent_uid` to the root
+    /// is pinned recursively. The ancestor check walks `parent_lid` to the root
     /// via a CTE; a direct pin is honoured even when the node has no `nodes` row
     /// yet (e.g. a CLI that never hydrates the node cache).
     ///
-    /// The walk is depth-capped like [`super::utils::path_of`]: a `parent_uid`
+    /// The walk is depth-capped like [`super::utils::path_of`]: a parent
     /// cycle is corrupt data the API can hand us, and `UNION ALL` over one never
     /// terminates — while holding the daemon's only SQLite connection, on a path
     /// that runs per cached read.
@@ -85,11 +85,11 @@ impl Db {
         let anc: Option<i64> = conn
             .query_row(
                 &format!(
-                    "WITH RECURSIVE anc(uid, parent_uid, depth) AS (
+                    "WITH RECURSIVE anc(uid, parent_lid, depth) AS (
-                       SELECT uid, parent_uid, 0 FROM nodes WHERE uid = ?1
+                       SELECT uid, parent_lid, 0 FROM nodes WHERE uid = ?1
                        UNION ALL
-                       SELECT n.uid, n.parent_uid, anc.depth + 1
+                       SELECT n.uid, n.parent_lid, anc.depth + 1
-                       FROM nodes n JOIN anc ON n.uid = anc.parent_uid
+                       FROM nodes n JOIN anc ON n.lid = anc.parent_lid
                        WHERE anc.depth < {MAX_PATH_DEPTH}
                      )
                      SELECT 1 FROM anc a JOIN pins p ON p.uid = a.uid
@@ -109,10 +109,11 @@ impl Db {
     pub fn pinned_uids(&self) -> Result<Vec<String>> {
         let conn = self.read();
         let mut stmt = conn.prepare(
-            "WITH RECURSIVE sub(uid) AS (
+            "WITH RECURSIVE sub(uid, lid) AS (
-               SELECT uid FROM pins WHERE recursive = 1
+               SELECT p.uid, n.lid FROM pins p LEFT JOIN nodes n ON n.uid = p.uid
+                WHERE p.recursive = 1
                UNION
-               SELECT n.uid FROM nodes n JOIN sub ON n.parent_uid = sub.uid
+               SELECT n.uid, n.lid FROM nodes n JOIN sub ON n.parent_lid = sub.lid
              )
              SELECT uid FROM sub
              UNION
@@ -126,15 +127,16 @@ impl Db {
         Ok(out)
     }
 
-    /// Every descendant uid of `folder` (all depths), via a `parent_uid` CTE.
+    /// Every descendant uid of `folder` (all depths), via a `parent_lid` CTE.
     /// Used to evict a recursively-pinned subtree's cached blobs on unpin.
     pub fn descendants(&self, folder: &str) -> Result<Vec<String>> {
         let conn = self.read();
         let mut stmt = conn.prepare(
-            "WITH RECURSIVE sub(uid) AS (
+            "WITH RECURSIVE sub(uid, lid) AS (
-               SELECT uid FROM nodes WHERE parent_uid = ?1
+               SELECT c.uid, c.lid FROM nodes c JOIN nodes f ON c.parent_lid = f.lid
+                WHERE f.uid = ?1
                UNION
-               SELECT n.uid FROM nodes n JOIN sub ON n.parent_uid = sub.uid
+               SELECT n.uid, n.lid FROM nodes n JOIN sub ON n.parent_lid = sub.lid
              )
              SELECT uid FROM sub",
         )?;

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

@@ -95,11 +95,27 @@ impl Db {
     /// Resolve a persisted node's effective access through its nearest recorded
     /// share root. `None` means the node itself is not persisted, which callers
     /// must not treat as owned: stale handles need to fail closed.
+    ///
+    /// A stand-in ([`local_uid`](super::local_uid)) finds its row by local id,
+    /// so it still does once its create has landed and the row has the uid
+    /// Drive gave it. The tree learns that uid a moment later, and a rename in
+    /// between was refused (`docs/BUGS.md` B174).
     pub fn effective_node_access(&self, uid: &NodeUid) -> Result<Option<Access>> {
         let conn = self.read();
+        let key = uid.to_string();
+        let key = match super::local_lid(&key) {
+            Some(lid) => conn
+                .query_row("SELECT uid FROM nodes WHERE lid = ?1", [lid], |row| {
+                    row.get::<_, Option<String>>(0)
+                })
+                .optional()?
+                .flatten()
+                .unwrap_or(key),
+            None => key,
+        };
         let exists: bool = conn.query_row(
-            "SELECT EXISTS(SELECT 1 FROM nodes WHERE uid = ?1)",
+            "SELECT EXISTS(SELECT 1 FROM nodes WHERE uid = ?1 AND node_json IS NOT NULL)",
-            [uid.to_string()],
+            [&key],
             |row| row.get(0),
         )?;
         if !exists {
@@ -107,25 +123,26 @@ impl Db {
         }
         let value = conn
             .query_row(
-                "WITH RECURSIVE ancestors(uid, parent_uid, depth, path) AS (
+                "WITH RECURSIVE ancestors(uid, parent_uid, parent_lid, depth, path) AS (
-                   SELECT uid, parent_uid, 0, char(31) || uid || char(31)
+                   SELECT uid, parent_uid, parent_lid, 0, char(31) || uid || char(31)
                      FROM nodes WHERE uid = ?1
                    UNION ALL
-                   SELECT a.parent_uid, n.parent_uid, a.depth + 1,
+                   SELECT COALESCE(n.uid, a.parent_uid), n.parent_uid, n.parent_lid,
-                          a.path || a.parent_uid || char(31)
+                          a.depth + 1,
+                          a.path || COALESCE(n.uid, a.parent_uid) || char(31)
                      FROM ancestors a
-                     LEFT JOIN nodes n ON n.uid = a.parent_uid
+                     LEFT JOIN nodes n ON n.lid = a.parent_lid
                     WHERE a.parent_uid IS NOT NULL
                       AND instr(
                             a.path,
-                            char(31) || a.parent_uid || char(31)
+                            char(31) || COALESCE(n.uid, a.parent_uid) || char(31)
                           ) = 0
                  )
                  SELECT sa.access
                    FROM ancestors a JOIN share_access sa ON sa.root_uid = a.uid
                   ORDER BY a.depth ASC
                   LIMIT 1",
-                [uid.to_string()],
+                [&key],
                 |row| row.get::<_, String>(0),
             )
             .optional()?;

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

@@ -25,8 +25,8 @@ pub struct StoredSyncFolder {
 }
 
 /// One per-file sync baseline row: what a path looked like on both sides at the
-/// last successful sync, so the next reconcile can tell which side changed
+/// last successful sync, so the next reconcile can tell which side changed.
-/// (devices.md Phase 2). `remote_rev`/`remote_hash` hold the remote signature —
+/// `remote_rev`/`remote_hash` hold the remote signature —
 /// its modification time and size as strings — since no cheap content hash is
 /// exposed; change detection is `(mtime, size)` on each side.
 #[derive(Clone, Debug, PartialEq)]
@@ -39,7 +39,7 @@ pub struct StoredSyncEntry {
     ///
     /// `local_mtime` alone cannot tell an edit that landed inside the same
     /// second as the last sync — and left the file the same length — from no
-    /// edit at all, so those never uploaded (bugs.md B25). `None` on a row
+    /// edit at all, so those never uploaded (`docs/BUGS.md` B25). `None` on a row
     /// written before schema 28, which the comparison reads as "compare whole
     /// seconds", so upgrading does not make an entire mirror look changed.
     pub local_mtime_ns: Option<i64>,
@@ -139,6 +139,17 @@ impl Db {
         Ok(())
     }
 
+    /// Re-point a synced folder at the share that now holds its remote folder,
+    /// after the folder moved to another device without changing its uid.
+    pub fn sync_folder_set_share(&self, id: i64, share_id: &str) -> Result<()> {
+        let conn = self.conn.lock();
+        conn.execute(
+            "UPDATE sync_folder SET remote_share_id = ?2 WHERE id = ?1",
+            params![id, share_id],
+        )?;
+        Ok(())
+    }
+
     /// Queue (or, with `None`, withdraw) a mode the folder should move to once it
     /// is safe to switch.
     pub fn sync_folder_set_pending_mode(&self, id: i64, mode: Option<&str>) -> Result<()> {
@@ -345,7 +356,7 @@ impl Db {
     /// Drop the entire baseline for a folder. Used when flipping ondemand→mirror:
     /// the local tree was evicted, so the old baseline is stale and would make the
     /// next reconcile mistake "locally deleted" for "must re-download". Clearing it
-    /// leaves an empty baseline + full remote = pure download (devices.md P3).
+    /// leaves an empty baseline + full remote = pure download.
     pub fn sync_entries_clear(&self, folder_id: i64) -> Result<()> {
         let conn = self.conn.lock();
         conn.execute(

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

@@ -102,5 +102,5 @@ impl Db {
         Ok(seen)
     }
 
-    // ---- device sync (devices.md) -----------------------------------------
+    // ---- device sync -----------------------------------------
 }

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

@@ -72,18 +72,18 @@ pub(super) fn path_of(conn: &Connection, uid: &str) -> Result<String> {
     }
 }
 
-/// Resolve a path by walking `parent_uid` to the root via a recursive CTE.
+/// Resolve a path by walking `parent_lid` to the root via a recursive CTE.
 ///
-/// A cycle in `parent_uid` is corrupt data the API can still hand us, and
+/// A cycle in the parents is corrupt data the API can still hand us, and
 /// `UNION ALL` over one never terminates — the walk is therefore depth-capped
 /// and returns the truncated path rather than hanging the caller.
 pub(super) fn walk_path_of(conn: &Connection, uid: &str) -> Result<String> {
     let mut stmt = conn.prepare(&format!(
-        "WITH RECURSIVE anc(uid, parent_uid, name, depth) AS (
+        "WITH RECURSIVE anc(parent_lid, parent_uid, name, depth) AS (
-           SELECT uid, parent_uid, name, 0 FROM nodes WHERE uid = ?1
+           SELECT parent_lid, parent_uid, name, 0 FROM nodes WHERE uid = ?1
            UNION ALL
-           SELECT n.uid, n.parent_uid, n.name, anc.depth + 1
+           SELECT n.parent_lid, n.parent_uid, n.name, anc.depth + 1
-           FROM nodes n JOIN anc ON n.uid = anc.parent_uid
+           FROM nodes n JOIN anc ON n.lid = anc.parent_lid
            WHERE anc.depth < {MAX_PATH_DEPTH}
          )
          SELECT name, parent_uid FROM anc ORDER BY depth DESC"

crates/pdfs-core/src/error.rs

@@ -32,6 +32,16 @@ pub enum Error {
     #[error("saved session can no longer unlock your keys — run `pdfs login` again")]
     ReloginRequired,
 
+    /// The account has a separate mailbox password that has not been entered
+    /// since login, so its keys cannot be unlocked. The fix is
+    /// [`auth::unlock`](crate::auth::unlock), not a new login.
+    #[error("account is locked — enter the mailbox password with `pdfs unlock`")]
+    Locked,
+
+    /// The mailbox password was checked against the account and is wrong.
+    #[error("that mailbox password does not unlock your account")]
+    WrongMailboxPassword,
+
     /// The login was gated behind human verification. Not a failure the user can
     /// fix by retrying: the challenge has to be solved and the login restarted
     /// with the resulting token (see [`auth::login_verified`](crate::auth::login_verified)).
@@ -199,9 +209,11 @@ 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::HumanVerificationRequired(_) => {
+            Error::NotLoggedIn
-                ErrorKind::Denied
+            | 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,
@@ -266,6 +278,23 @@ fn api_kind(code: proton_sdk::api::ResponseCode) -> ErrorKind {
     }
 }
 
+/// Whether `e` says the session itself is gone: its refresh token was refused,
+/// or the account was deleted or disabled.
+///
+/// Nothing but a new login helps then, and no retry will ever succeed, so a
+/// caller must not take it for a lost connection and wait for it to come back
+/// (issue #35: a revoked session was shown as "offline" for good).
+pub fn session_revoked(e: &proton_sdk::ProtonError) -> bool {
+    use proton_sdk::api::ResponseCode as C;
+    match e {
+        proton_sdk::ProtonError::Api(api) => {
+            api.is_invalid_refresh_token()
+                || matches!(api.code, C::AccountDeleted | C::AccountDisabled)
+        }
+        _ => false,
+    }
+}
+
 /// The result every request-serving method in the daemon returns.
 pub type CoreResult<T> = std::result::Result<T, CoreError>;
 
@@ -297,6 +326,17 @@ mod tests {
         assert_eq!(api_kind(C::ProtonDriveUnknown), ErrorKind::Remote);
     }
 
+    #[test]
+    fn only_a_refused_refresh_or_a_closed_account_revokes_the_session() {
+        assert!(session_revoked(&api(C::InvalidRefreshToken)));
+        assert!(session_revoked(&api(C::AccountDeleted)));
+        assert!(session_revoked(&api(C::AccountDisabled)));
+        // One file the account may not touch says nothing about the session.
+        assert!(!session_revoked(&api(C::Forbidden)));
+        assert!(!session_revoked(&api(C::Timeout)));
+        assert!(!session_revoked(&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.

crates/pdfs-core/src/kernelkey.rs

@@ -0,0 +1,233 @@
+//! A secret held in the Linux kernel keyring, for as long as the user is logged in.
+//!
+//! This is where the key passphrases of a two-password account live by default:
+//! the mailbox password is never stored, and the secrets derived from it are
+//! kept in kernel memory — not on disk, not in the Secret Service — and vanish
+//! when the user's last session ends or the machine reboots. Both the daemon and
+//! `pdfs unlock` reach the same entry because it hangs off the *user* keyring.
+//! It is also where session tokens wait while the Secret Service refuses them
+//! ([`UNSAVED_TOKENS`]), so they outlive the process that holds them.
+//!
+//! Kernel keys are not paged to swap, are invisible to other users, and are
+//! wiped by [`clear`] (`KEYCTL_REVOKE`), which makes them a better home than a
+//! process's heap. Processes of the same user can still read them, exactly as
+//! they could ptrace the daemon: this protects against disk, backup and other
+//! users, not against code already running as you.
+//!
+//! The keyring may be unavailable (a container, a kernel built without
+//! `CONFIG_KEYS`); every operation then reports it as an error and the caller
+//! falls back to asking again, never to storing the secret somewhere weaker.
+
+use std::io;
+
+use zeroize::Zeroizing;
+
+/// One secret in the user keyring, by its description. Descriptions are
+/// namespaced so they cannot collide with another program's keys.
+pub struct Key {
+    description: &'static [u8],
+}
+
+/// The account's key passphrases (see the module docs).
+#[cfg(not(test))]
+pub const PASSPHRASES: Key = Key {
+    description: b"pdfs:key-passphrases\0",
+};
+/// Tests must never touch a real unlock.
+#[cfg(test)]
+pub const PASSPHRASES: Key = Key {
+    description: b"pdfs:key-passphrases:test\0",
+};
+
+/// Session tokens the Secret Service refused to store, until it takes them.
+/// A refresh token held only in a process's memory dies with the process.
+#[cfg(not(test))]
+pub const UNSAVED_TOKENS: Key = Key {
+    description: b"pdfs:unsaved-tokens\0",
+};
+#[cfg(test)]
+pub const UNSAVED_TOKENS: Key = Key {
+    description: b"pdfs:unsaved-tokens:test\0",
+};
+
+const KEY_TYPE: &[u8] = b"user\0";
+
+const KEY_SPEC_USER_KEYRING: i32 = -4;
+const KEYCTL_REVOKE: libc::c_long = 3;
+const KEYCTL_SETPERM: libc::c_long = 5;
+const KEYCTL_SEARCH: libc::c_long = 10;
+const KEYCTL_READ: libc::c_long = 11;
+
+/// Possessor and owner may view, read, write, search, link and set attributes;
+/// group and others get nothing.
+///
+/// A new key's default grants the owner only *view*, and read access to the
+/// possessor. A process possesses the user keyring only when its session
+/// keyring links to it, which a systemd user service or a container does not
+/// guarantee — so with the default, the daemon could store a key it then
+/// cannot read back. The owner is the same user that could ptrace the daemon
+/// anyway, so granting it read access gives up nothing.
+const PERM_OWNER_AND_POSSESSOR: u32 = 0x3f3f_0000;
+
+fn last_error<T>() -> io::Result<T> {
+    Err(io::Error::last_os_error())
+}
+
+fn find(description: &[u8]) -> io::Result<Option<libc::c_long>> {
+    // SAFETY: both strings are NUL-terminated and outlive the call.
+    let id = unsafe {
+        libc::syscall(
+            libc::SYS_keyctl,
+            KEYCTL_SEARCH,
+            KEY_SPEC_USER_KEYRING,
+            KEY_TYPE.as_ptr(),
+            description.as_ptr(),
+            0,
+        )
+    };
+    if id >= 0 {
+        return Ok(Some(id));
+    }
+    let err = io::Error::last_os_error();
+    match err.raw_os_error() {
+        // ENOKEY: not stored. EKEYREVOKED/EKEYEXPIRED: stored once, now gone.
+        Some(libc::ENOKEY | libc::EKEYREVOKED | libc::EKEYEXPIRED) => Ok(None),
+        _ => Err(err),
+    }
+}
+
+/// Stop this process from being core-dumped or ptraced by an unprivileged
+/// process of the same user, so the secrets in its memory stay out of crash
+/// reports. Call once at start of a long-lived process that holds them.
+pub fn forbid_dumps() {
+    // SAFETY: `PR_SET_DUMPABLE` takes plain integers and only affects this process.
+    let rc = unsafe { libc::prctl(libc::PR_SET_DUMPABLE, 0, 0, 0, 0) };
+    if rc != 0 {
+        tracing::warn!(error = %io::Error::last_os_error(), "could not mark the process non-dumpable");
+    }
+}
+
+impl Key {
+    /// Store `secret`, replacing any earlier one.
+    pub fn store(&self, secret: &[u8]) -> io::Result<()> {
+        // SAFETY: strings are NUL-terminated; the payload pointer/length pair
+        // describes `secret`, which outlives the call.
+        let id = unsafe {
+            libc::syscall(
+                libc::SYS_add_key,
+                KEY_TYPE.as_ptr(),
+                self.description.as_ptr(),
+                secret.as_ptr(),
+                secret.len(),
+                KEY_SPEC_USER_KEYRING,
+            )
+        };
+        if id < 0 {
+            return last_error();
+        }
+        // SAFETY: plain integer arguments.
+        let rc = unsafe {
+            libc::syscall(
+                libc::SYS_keyctl,
+                KEYCTL_SETPERM,
+                id,
+                PERM_OWNER_AND_POSSESSOR,
+            )
+        };
+        if rc < 0 {
+            // A key whose permissions are unknown is not one to leave behind.
+            let err = io::Error::last_os_error();
+            let _ = self.clear();
+            return Err(err);
+        }
+        Ok(())
+    }
+
+    /// Read the stored secret, or `None` when there is none.
+    pub fn load(&self) -> io::Result<Option<Zeroizing<Vec<u8>>>> {
+        let Some(id) = find(self.description)? else {
+            return Ok(None);
+        };
+        // Size first, then read; retry if the key was replaced in between.
+        for _ in 0..3 {
+            // SAFETY: a null buffer asks the kernel only for the payload length.
+            let len = unsafe {
+                libc::syscall(
+                    libc::SYS_keyctl,
+                    KEYCTL_READ,
+                    id,
+                    std::ptr::null_mut::<u8>(),
+                    0usize,
+                )
+            };
+            if len < 0 {
+                return match io::Error::last_os_error().raw_os_error() {
+                    Some(libc::ENOKEY | libc::EKEYREVOKED | libc::EKEYEXPIRED) => Ok(None),
+                    _ => last_error(),
+                };
+            }
+            let mut buf = Zeroizing::new(vec![0u8; len as usize]);
+            // SAFETY: `buf` is `len` writable bytes.
+            let read = unsafe {
+                libc::syscall(
+                    libc::SYS_keyctl,
+                    KEYCTL_READ,
+                    id,
+                    buf.as_mut_ptr(),
+                    buf.len(),
+                )
+            };
+            if read < 0 {
+                return last_error();
+            }
+            if read as usize <= buf.len() {
+                buf.truncate(read as usize);
+                return Ok(Some(buf));
+            }
+        }
+        Err(io::Error::other("the key changed while it was being read"))
+    }
+
+    /// Remove the stored secret. Succeeds when there is none.
+    pub fn clear(&self) -> io::Result<()> {
+        let Some(id) = find(self.description)? else {
+            return Ok(());
+        };
+        // SAFETY: plain integer arguments.
+        let rc = unsafe { libc::syscall(libc::SYS_keyctl, KEYCTL_REVOKE, id) };
+        if rc < 0 {
+            return match io::Error::last_os_error().raw_os_error() {
+                Some(libc::ENOKEY | libc::EKEYREVOKED) => Ok(()),
+                _ => last_error(),
+            };
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // The kernel keyring is process-wide state and a sandbox may not offer it,
+    // so one test covers the whole round trip and skips when it is unavailable.
+    #[test]
+    fn stored_secret_round_trips_and_clears() {
+        if PASSPHRASES.store(b"probe").is_err() {
+            eprintln!("kernel keyring unavailable; skipping");
+            return;
+        }
+        let saved = PASSPHRASES
+            .load()
+            .unwrap()
+            .expect("stored secret is readable");
+        assert_eq!(saved.as_slice(), b"probe");
+
+        PASSPHRASES.store(b"replaced").unwrap();
+        assert_eq!(PASSPHRASES.load().unwrap().unwrap().as_slice(), b"replaced");
+
+        PASSPHRASES.clear().unwrap();
+        assert!(PASSPHRASES.load().unwrap().is_none());
+        PASSPHRASES.clear().unwrap();
+    }
+}

crates/pdfs-core/src/lib.rs

@@ -10,6 +10,7 @@ pub mod config;
 pub mod control;
 pub mod db;
 pub mod error;
+pub mod kernelkey;
 pub mod localindex;
 pub mod menu;
 pub mod mounts;

crates/pdfs-core/src/profile.rs

@@ -1,4 +1,4 @@
-//! The machine profile that travels with a device (features.md 5.3).
+//! The machine profile that travels with a device.
 //!
 //! Sync folder mappings, pins, and the settings that shape them live in
 //! `cache.db` and `config.json` — both on the local disk. When that disk dies,

crates/pdfs-core/src/syncignore.rs

@@ -1,4 +1,4 @@
-//! Selective-sync ignore rules for mirror folders (features.md 1.1).
+//! Selective-sync ignore rules for mirror folders.
 //!
 //! A mirror folder otherwise uploads every path beneath its root, which for a
 //! project directory means `node_modules/`, `.git/`, and `target/` — quota

crates/pdfs-fuse/Cargo.toml

@@ -15,6 +15,7 @@ zip.workspace = true
 sha1.workspace = true
 proton-drive-rs.workspace = true
 futures.workspace = true
+async-trait.workspace = true
 tokio.workspace = true
 tracing.workspace = true
 fuser.workspace = true
@@ -24,3 +25,6 @@ base64.workspace = true
 image.workspace = true
 notify = "8"
 parking_lot.workspace = true
+
+[dev-dependencies]
+tracing-subscriber.workspace = true

crates/pdfs-fuse/src/background.rs

@@ -2,6 +2,7 @@
 
 use super::*;
 use crate::shutdown::Shutdown;
+use pdfs_core::error::session_revoked;
 
 /// Drop `uid` from one mount's tree and tell that mount's kernel session the
 /// entry is gone. Shared by the trash and delete paths, which differ only in
@@ -97,15 +98,13 @@ fn event_serializes_shared_publication(event: &DriveEvent, own_volume: &VolumeId
 /// entry forces the next `lookup`/`readdir` to re-enumerate from the remote, so
 /// most events only need to invalidate listings rather than re-fetch eagerly.
 ///
-/// Applied to **every** mounted inode space, not just the primary one. This task
+/// Applied to the tree every mount shares, and told to **every** mounted
-/// is per-daemon while node state is per-mount, and a `DriveEvent` names a uid,
+/// session. A `DriveEvent` names a uid, not a mount, so a file trashed from
-/// not a mount — so a file trashed from another device has to be withdrawn from
+/// another device has to be withdrawn from whichever of our sessions is showing
-/// whichever of our sessions is showing it, which for anything under a sync
+/// it — which for anything under a sync folder is a [`Core::fork_state`] fork.
-/// folder is a [`Core::fork_state`] fork rather than `core.state`. Reaching for
+/// Telling the primary session alone left forks serving a deleted file, the
-/// the primary state alone left forks serving a deleted file indefinitely, the
+/// read-side twin of `docs/BUGS.md` B74. [`Core::for_each_mount`] sends what
-/// read-side twin of `docs/BUGS.md` B74. Inode numbers are per-mount, so each
+/// the kernel needs to hear to every session.
-/// mount must be notified through its **own** channel; that pairing is what
-/// [`Core::for_each_mount`] exists to preserve.
 fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdfs_core::Result<()> {
     let foreign_delete = is_foreign_node_delete(event, &core.primary_root_uid.volume_id);
     let serializes_shared_publication =
@@ -145,7 +144,7 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
             // create, and re-fetching would replace the size and mtime of the
             // write we just accepted with the stale revision's — making a file
             // that was copied in seconds ago read as empty until its upload
-            // lands (offline.md Phase 3).
+            // lands.
             //
             // A write that has already drained is the same story one step later:
             // the drain brought the tree level with the revision it sealed, so
@@ -233,6 +232,48 @@ fn acknowledge_applied_event(
     Ok(id)
 }
 
+/// How many applied node-update ids [`RecentEvents`] remembers. Far more than a
+/// replay can reach back: one comes from a batch whose last event was not its
+/// newest, so it repeats at most what that batch held.
+const RECENT_EVENTS: usize = 4096;
+
+/// The node updates applied lately, by event id, so one that comes round again
+/// is skipped rather than applied twice.
+///
+/// The feed can deliver the same event twice in a batch, and a batch whose
+/// events come out of order leaves the cursor short of its newest event, so the
+/// next poll replays what lay past it. An update applied twice is not harmless:
+/// the first copy of our own change claims the echo [`Core::note_self_change`]
+/// recorded, and the second, unclaimed, reads as someone else's edit and evicts
+/// the bytes a partial write is about to gap-fill from (docs/BUGS.md B123).
+///
+/// Only node updates: a delete is idempotent, and a continuity loss names the
+/// cursor it lost, which is an id already applied.
+#[derive(Default)]
+struct RecentEvents {
+    ids: HashSet<DriveEventId>,
+    order: VecDeque<DriveEventId>,
+}
+
+impl RecentEvents {
+    /// Record `event` as applied, reporting whether it was already.
+    fn repeat(&mut self, event: &DriveEvent) -> bool {
+        let DriveEvent::NodeUpdated { id, .. } = event else {
+            return false;
+        };
+        if !self.ids.insert(id.clone()) {
+            return true;
+        }
+        self.order.push_back(id.clone());
+        if self.order.len() > RECENT_EVENTS
+            && let Some(old) = self.order.pop_front()
+        {
+            self.ids.remove(&old);
+        }
+        false
+    }
+}
+
 /// The folders one batch of events changed, collected so the listings are
 /// dropped once at the end of the batch rather than once per event.
 ///
@@ -320,10 +361,10 @@ fn flush_dirty_parents(core: &Core, dirty: &DirtyParents) {
 /// only on fatal error.
 ///
 /// Takes the whole `Core` rather than the primary mount's pieces: an event has
-/// to be applied to every mounted inode space, and the registry that enumerates
+/// to reach every mounted session, and the registry that enumerates them lives
-/// them lives on the `Core` (see [`apply_event`]).
+/// on the `Core` (see [`apply_event`]).
 pub(super) async fn run_event_sync(
-    client: ProtonDriveClient,
+    client: Arc<dyn DriveApi>,
     scope: DriveEventScopeId,
     core: Core,
 ) {
@@ -335,7 +376,7 @@ pub(super) async fn run_event_sync(
         // server head; persist it so the next restart resumes instead of
         // reseeding (which would skip everything that changed offline).
         // Seeding needs the network, and this task also runs on mounts that
-        // started offline (offline.md Phase 1) — so retry rather than giving up,
+        // started offline — so retry rather than giving up,
         // which used to disable live sync for the life of the daemon.
         Ok(None) => {
             // Nothing says what changed before this cursor, so a persisted SDK
@@ -362,6 +403,12 @@ pub(super) async fn run_event_sync(
                         }
                         break Some(c.clone());
                     }
+                    // Refused for good: retrying would be refused the same way
+                    // for the life of the daemon. The next login restarts it.
+                    Err(e) if session_revoked(&e) => {
+                        core.mark_session_expired("seed event cursor", &e);
+                        return;
+                    }
                     Err(e) => {
                         warn!(error = %e, ?delay, "seed event cursor failed; retrying");
                         tokio::time::sleep(delay).await;
@@ -377,6 +424,7 @@ pub(super) async fn run_event_sync(
     };
     info!(?cursor, "event sync started");
 
+    let mut recent = RecentEvents::default();
     loop {
         core.next_poll(POLL_INTERVAL).await;
         let events = match link::bounded(client.enumerate_events(&scope, cursor.as_ref())).await {
@@ -397,6 +445,11 @@ pub(super) async fn run_event_sync(
         // did apply.
         let mut dirty = DirtyParents::default();
         for event in &events {
+            if recent.repeat(event) {
+                debug!(id = %event.id().as_str(), "skipping an event already applied");
+                cursor = Some(event.id().clone());
+                continue;
+            }
             // Converge the SDK's own caches (folder keys, entity cache) on the
             // server before applying the event to our tree. Without this, a node
             // re-keyed/moved by another client keeps a stale key in the SDK for
@@ -456,6 +509,10 @@ pub(super) async fn run_photos_event_sync(core: Core) {
                 debug!("no photos volume; photo event sync not started");
                 return;
             }
+            Err(error) if session_revoked(&error) => {
+                core.mark_session_expired("read the photos root", &error);
+                return;
+            }
             Err(error) => {
                 warn!(%error, "reading the photos root failed; retrying");
                 tokio::time::sleep(ONLINE_PROBE_MAX).await;
@@ -614,7 +671,7 @@ pub(super) fn run_local_index(
             scan_local_once(&db, &indexing, &transfers, &mountpoint);
         }
         // Interruptible, so teardown joins this thread instead of leaving it to
-        // keep rewriting the index for a mount that is gone (bugs.md B44).
+        // keep rewriting the index for a mount that is gone (`docs/BUGS.md` B44).
         if !shutdown.sleep(LOCAL_INDEX_CHECK) {
             return;
         }
@@ -664,7 +721,7 @@ fn scan_local_once(
 
     // The walk has no idea how many files it will find, so the job counts what it
     // has seen and stays indeterminate.
-    let job = transfers.begin_job("Indexing this computer");
+    let job = transfers.begin_background_job("Indexing this computer");
     job.detail("Scanning your files");
     let walked = localindex::scan(&[home], &excludes, |batch| {
         if let Err(e) = db.local_upsert_batch(generation, &batch) {
@@ -717,6 +774,43 @@ mod tests {
         }
     }
 
+    #[test]
+    fn a_node_update_seen_again_is_skipped_but_other_events_are_not() {
+        let update = |id: &str| DriveEvent::NodeUpdated {
+            id: DriveEventId::from(id),
+            node_uid: uid("file"),
+            parent_node_uid: None,
+            is_trashed: false,
+            is_shared: false,
+        };
+        let mut recent = RecentEvents::default();
+        assert!(!recent.repeat(&update("e1")));
+        assert!(!recent.repeat(&update("e2")));
+        assert!(recent.repeat(&update("e1")), "a duplicate or replay");
+        let lost = DriveEvent::ContinuityLost {
+            id: DriveEventId::from("e2"),
+        };
+        assert!(!recent.repeat(&lost), "names the cursor, which was applied");
+    }
+
+    #[test]
+    fn recent_events_forget_the_oldest_past_their_bound() {
+        let update = |n: usize| DriveEvent::NodeUpdated {
+            id: DriveEventId::from(format!("e{n}")),
+            node_uid: uid("file"),
+            parent_node_uid: None,
+            is_trashed: false,
+            is_shared: false,
+        };
+        let mut recent = RecentEvents::default();
+        for n in 0..=RECENT_EVENTS {
+            assert!(!recent.repeat(&update(n)));
+        }
+        assert_eq!(recent.ids.len(), RECENT_EVENTS);
+        assert!(!recent.repeat(&update(0)), "the oldest was forgotten");
+        assert!(recent.repeat(&update(RECENT_EVENTS)));
+    }
+
     #[test]
     fn foreign_delete_invalidates_an_earlier_refresh_generation() {
         let own_volume = VolumeId::from("own");

crates/pdfs-fuse/src/control.rs

@@ -163,8 +163,8 @@ fn read_request_line(reader: &mut impl BufRead) -> std::io::Result<Option<String
 /// Turn a CLI-supplied path into the mount that owns it and the path relative
 /// to *that* mount's root.
 ///
-/// [`rel_to_mount`] is the older, primary-only reading, and it is what every
+/// [`rel_to_mount`] is the older, primary-only reading, and it is what most
-/// mutating request still uses. It rejects anything outside the primary
+/// requests still use. It rejects anything outside the primary
 /// mountpoint, which leaves a secondary on-demand mount — a synced folder
 /// switched out of mirror mode — with no way to be named at all: `pdfs ls` and
 /// `pdfs refresh` both answered "is not under the mountpoint", so a folder
@@ -185,11 +185,14 @@ fn route_to_mount(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Cor
     rel_to_mount(mountpoint, path).map(|rel| (core.clone(), rel))
 }
 
-/// [`route_to_mount`] for a conflict copy. The listing names a copy inside a
+/// [`route_to_mount`] for a request that changes what it names: trash, rename,
-/// synced folder by its absolute local path (`docs/BUGS.md` B99), so the
+/// create a folder, resolve a conflict. Each has to run against the on-demand
-/// resolve has to run against the on-demand mount serving it. A mirror folder
+/// mount serving the path, and `pdfs rm ~/Downloads/x` answered "is not under
-/// has no mount to run against: its copy is an ordinary local file.
+/// the mountpoint" while `pdfs move` took the same path. The conflict listing
-fn route_conflict(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core, PathBuf)> {
+/// names a copy in a synced folder by its absolute local path (`docs/BUGS.md`
+/// 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)> {
     let routed = route_to_mount(core, mountpoint, path).map_err(|e| {
         let p = Path::new(path);
         let mirrored = core
@@ -200,7 +203,7 @@ fn route_conflict(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Cor
             .any(|folder| folder.mode == "mirror" && p.starts_with(&folder.local_path));
         if mirrored {
             CoreError::invalid(format!(
-                "{path} is in a mirrored folder; rename or delete the local file there"
+                "{path} is in a mirrored folder; change the local file there instead"
             ))
         } else {
             e
@@ -217,6 +220,27 @@ fn route_conflict(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Cor
     }
 }
 
+/// [`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
+/// ~/Downloads` from trashing the folder out from under its own mount.
+fn route_node(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core, PathBuf)> {
+    let routed = route_change(core, mountpoint, path)?;
+    if below_root(&routed.1) {
+        Ok(routed)
+    } else {
+        Err(CoreError::invalid(format!(
+            "{path} is the root of a synced location and cannot be changed"
+        )))
+    }
+}
+
+/// Whether a mount-relative path names something below the mount's root.
+fn below_root(rel: &Path) -> bool {
+    rel.components()
+        .any(|component| matches!(component, Component::Normal(_)))
+}
+
 /// Turn a CLI-supplied path into a mountpoint-relative path. An absolute path
 /// must live under `mountpoint`; a relative path is taken as already relative to
 /// the mount root.
@@ -291,6 +315,9 @@ impl Drop for RefreshGuard {
 pub(crate) fn status_response(core: &Core, username: &str, mountpoint: &Path) -> CtlResponse {
     let pins = core.cache.list_pins();
     let queued = core.db.pending_op_counts().unwrap_or_default();
+    // Read after the queue: the drain counts an upload as landing before it
+    // retires the op, so one of the two always has it (B119).
+    let landing = core.landing_uploads.load(Ordering::SeqCst);
     let staging = core.cache.staging_usage();
     CtlResponse::Status {
         parked_uploads: queued.parked.max(0) as u64,
@@ -307,7 +334,9 @@ pub(crate) fn status_response(core: &Core, username: &str, mountpoint: &Path) ->
         budget: core.cache.budget(),
         pins,
         online: core.online.load(Ordering::Relaxed),
-        pending_uploads: queued.uploads.max(0) as u64,
+        session_expired: core.session_expired(),
+        tokens_unsaved: pdfs_core::auth::tokens_unsaved(),
+        pending_uploads: queued.uploads.max(0) as u64 + landing,
         pending_changes: queued.changes.max(0) as u64,
     }
 }
@@ -342,7 +371,7 @@ fn touched_topics(request: &CtlRequest) -> &'static [Topic] {
             RefreshScope::Photos { .. } => &[],
         },
         R::RenameDevice { .. } | R::DeleteDevice { .. } => &[Topic::Devices],
-        R::AdoptDevice { .. } => &[Topic::Devices, Topic::Locations],
+        R::AdoptDevice { .. } | R::MigrateDevice { .. } => &[Topic::Devices, Topic::Locations],
         R::AddSyncFolder { .. }
         | R::RemoveSyncFolder { .. }
         | R::SetSyncFolderMode { .. }
@@ -350,6 +379,7 @@ fn touched_topics(request: &CtlRequest) -> &'static [Topic] {
         | R::RestoreSyncFolders { .. }
         | R::RestoreDeviceFolders { .. } => &[Topic::Locations, Topic::Devices],
         R::RetryPendingOp { .. } => &[Topic::Queue],
+        R::DiscardPendingOp { .. } => &[Topic::Queue, Topic::Files],
         R::ResolveConflict { .. } => &[Topic::Files, Topic::Trash, Topic::Conflicts],
         R::ShareNode { .. }
         | R::ShareNodeByUid { .. }
@@ -959,8 +989,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             },
             Err(e) => CtlResponse::error(e),
         },
-        Ok(CtlRequest::Rename { path, new_name }) => match rel_to_mount(mountpoint, &path) {
+        Ok(CtlRequest::Rename { path, new_name }) => match route_node(core, mountpoint, &path) {
-            Ok(rel) => match core.rename(&rel, &new_name) {
+            Ok((core, rel)) => match core.rename(&rel, &new_name) {
                 Ok(name) => {
                     core.log_activity(ActivityKind::Rename, &name, format!("was {path}"), true);
                     CtlResponse::Ok {
@@ -1017,8 +1047,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 (Err(e), _) | (_, Err(e)) => CtlResponse::error(e),
             }
         }
-        Ok(CtlRequest::Delete { path }) => match rel_to_mount(mountpoint, &path) {
+        Ok(CtlRequest::Delete { path }) => match route_node(core, mountpoint, &path) {
-            Ok(rel) => match core.delete(&rel) {
+            Ok((core, rel)) => match core.delete(&rel) {
                 Ok(name) => {
                     core.log_activity(ActivityKind::Trash, &name, "", true);
                     CtlResponse::Ok {
@@ -1032,21 +1062,23 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             },
             Err(e) => CtlResponse::error(e),
         },
-        Ok(CtlRequest::CreateFolder { parent, name }) => match rel_to_mount(mountpoint, &parent) {
+        Ok(CtlRequest::CreateFolder { parent, name }) => {
-            Ok(parent_rel) => match core.create_folder(&parent_rel, &name) {
+            match route_change(core, mountpoint, &parent) {
-                Ok(name) => {
+                Ok((core, parent_rel)) => match core.create_folder(&parent_rel, &name) {
-                    core.log_activity(ActivityKind::CreateFolder, &name, "", true);
+                    Ok(name) => {
-                    CtlResponse::Ok {
+                        core.log_activity(ActivityKind::CreateFolder, &name, "", true);
-                        message: format!("created folder {name}"),
+                        CtlResponse::Ok {
+                            message: format!("created folder {name}"),
+                        }
                     }
-                }
+                    Err(e) => {
-                Err(e) => {
+                        core.log_activity(ActivityKind::CreateFolder, &name, &e, false);
-                    core.log_activity(ActivityKind::CreateFolder, &name, &e, false);
+                        CtlResponse::error(e)
-                    CtlResponse::error(e)
+                    }
-                }
+                },
-            },
+                Err(e) => CtlResponse::error(e),
-            Err(e) => CtlResponse::error(e),
+            }
-        },
+        }
         Ok(CtlRequest::UploadPaths { parent, sources }) => {
             match rel_to_mount(mountpoint, &parent) {
                 // Ack immediately and upload on a background thread: a directory tree
@@ -1267,6 +1299,10 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             Ok(message) => CtlResponse::Ok { message },
             Err(e) => CtlResponse::error(e),
         },
+        Ok(CtlRequest::MigrateDevice { uid }) => match core.migrate_device(&uid) {
+            Ok(message) => CtlResponse::Ok { message },
+            Err(e) => CtlResponse::error(e),
+        },
         Ok(CtlRequest::AddSyncFolder { local_path }) => {
             // Registering the device and uploading a folder tree far outlasts the
             // socket read timeout, so ack immediately and work on a background
@@ -1363,7 +1399,7 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             Err(e) => CtlResponse::error(e),
         },
         Ok(CtlRequest::ResolveConflict { path, keep }) => {
-            match route_conflict(core, mountpoint, &path) {
+            match route_change(core, mountpoint, &path) {
                 Ok((core, rel)) => match core.resolve_conflict(&rel, &keep) {
                     Ok(message) => CtlResponse::Ok { message },
                     Err(e) => CtlResponse::error(e),
@@ -1375,6 +1411,20 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             Ok(items) => CtlResponse::PendingOps { items },
             Err(e) => CtlResponse::error(e),
         },
+        Ok(CtlRequest::ExportPendingOp { id, dest }) => {
+            match core.export_pending_op(id, Path::new(&dest)) {
+                Ok(written) => CtlResponse::Ok {
+                    message: format!("wrote {} to {dest}", human_bytes(written)),
+                },
+                Err(e) => CtlResponse::error(e),
+            }
+        }
+        Ok(CtlRequest::DiscardPendingOp { id }) => match core.discard_pending_op(id) {
+            Ok(path) => CtlResponse::Ok {
+                message: format!("discarded the queued change to {path}"),
+            },
+            Err(e) => CtlResponse::error(e),
+        },
         Ok(CtlRequest::RetryPendingOp { id }) => match core.retry_pending_ops(id) {
             Ok(0) if id.is_some() => CtlResponse::Ok {
                 message: "nothing to retry: the operation is already due or waiting for a rename"
@@ -1772,7 +1822,7 @@ pub(crate) fn run_control_socket(
     info!("control socket listening");
     for conn in listener.incoming() {
         // Checked on every accept, including the deliberate poke teardown sends
-        // to wake this thread out of a blocking accept (bugs.md B44).
+        // to wake this thread out of a blocking accept (`docs/BUGS.md` B44).
         if core.shutdown.is_stopping() {
             info!("control socket closing");
             return;
@@ -1864,6 +1914,18 @@ mod request_limit_tests {
         assert!(rel_to_mount(mountpoint, "Photos/../../escape").is_err());
         assert!(rel_to_mount(mountpoint, "/mnt/elsewhere").is_err());
     }
+
+    /// `pdfs rm` and `pdfs rename` reach on-demand mounts, whose root is a whole
+    /// synced folder with a parent on Drive. Only a path below a root may get
+    /// through to the trash or rename call.
+    #[test]
+    fn only_a_path_below_a_mount_root_names_a_node() {
+        assert!(below_root(Path::new("Photos")));
+        assert!(below_root(Path::new("./Photos/2026")));
+        assert!(!below_root(Path::new("")));
+        assert!(!below_root(Path::new(".")));
+        assert!(!below_root(Path::new("./.")));
+    }
 }
 
 #[cfg(test)]

crates/pdfs-fuse/src/devices.rs

@@ -1,5 +1,5 @@
 //! This machine as a Proton Drive Device, and the local folders it keeps in
-//! step with the remote (devices.md).
+//! step with the remote.
 //!
 //! A sync folder runs in one of two modes. `mirror` keeps a real local tree that
 //! the engine in [`super::sync`] reconciles both ways; `ondemand` evicts that
@@ -19,6 +19,7 @@ use pdfs_core::control::{
 };
 use pdfs_core::db::{StoredDevice, StoredSyncFolder};
 use pdfs_core::mounts::MountMode;
+use pdfs_core::profile::PROFILE_DIR_NAME;
 use pdfs_core::{CoreError, CoreResult};
 use proton_drive_rs::proton_sdk::ids::{DeviceUid, NodeUid};
 use proton_drive_rs::{DeviceType, Node};
@@ -27,7 +28,7 @@ use tracing::{info, warn};
 
 use super::sync::{self, base_name};
 use super::{
-    Core, SecondaryInsertRejection, SecondaryMount, State, SwitchBlocked, clear_stale_mount,
+    Core, SecondaryInsertRejection, SecondaryMount, SwitchBlocked, clear_stale_mount,
     device_type_str, dir_is_empty, evict_dir_contents, fuse_connection_id, is_stale_mount,
     now_secs, parse_uid, spawn_session, sync_folder_info, this_hostname,
 };
@@ -114,6 +115,22 @@ pub(crate) fn set_adopted_device_uid(uid: Option<&str>) -> CoreResult<()> {
         .map_err(|e| CoreError::internal(format!("write config: {e}")))
 }
 
+/// The name a folder moved in from `device` takes when `name` is already
+/// taken under this device's root, or `None` when it can keep its own.
+fn migrated_name(name: &str, device: &str, taken: &[String]) -> Option<String> {
+    let free = |candidate: &str| !taken.iter().any(|t| t == candidate);
+    if free(name) {
+        return None;
+    }
+    let base = format!("{name} ({device})");
+    if free(&base) {
+        return Some(base);
+    }
+    (2..)
+        .map(|n| format!("{base} {n}"))
+        .find(|candidate| free(candidate))
+}
+
 impl Core {
     // ---- devices ----------------------------------------------------------
 
@@ -184,8 +201,8 @@ impl Core {
     }
 
     /// Adopt an existing device as *this* machine's, pinning it in `config.json`
-    /// so hostname changes and reinstalls stop registering duplicates
+    /// so hostname changes and reinstalls stop registering duplicates.
-    /// (features.md 5.1). `None` clears the pin and returns to hostname matching.
+    /// `None` clears the pin and returns to hostname matching.
     ///
     /// Refuses a uid that is not in the account: the whole point of the pin is
     /// that it is authoritative, so accepting a bad one would defer the failure
@@ -260,7 +277,108 @@ impl Core {
         })
     }
 
-    // ---- device folder sync (devices.md, Phase 1) -------------------------
+    /// Move every folder another device backs up into this machine's own
+    /// device, so this machine carries on backing them up as itself. The other
+    /// device stays registered, without those folders.
+    ///
+    /// Device roots all live on the main volume, so each folder is one
+    /// server-side move: nothing is downloaded or uploaded, and no quota is
+    /// used twice. A folder whose name is taken here keeps its content under
+    /// "<name> (<device>)". A failed folder does not stop the others, and a
+    /// second run picks up whatever is still left on the other device.
+    ///
+    /// Nothing is synced to this disk here. The moved folders are now this
+    /// device's, so the ordinary restore offers them. Only folders that were
+    /// already synced here from the other device are touched: their uid
+    /// survives the move but their share does not.
+    pub(crate) fn migrate_device(&self, uid: &str) -> CoreResult<String> {
+        let source = self.restore_source(Some(uid))?;
+        let target = self.ensure_device()?;
+        if source.uid == target.uid {
+            return Err(CoreError::invalid(format!(
+                "{} is this computer's own device",
+                source.name
+            )));
+        }
+        let bad_root = |d: &StoredDevice| {
+            parse_uid(&d.root_uid)
+                .ok_or_else(|| CoreError::internal(format!("bad device root uid: {}", d.root_uid)))
+        };
+        let (source_root, target_root) = (bad_root(&source)?, bad_root(&target)?);
+        if source_root.volume_id != target_root.volume_id {
+            return Err(CoreError::invalid(
+                "the two devices are on different Proton Drive volumes; copy it instead",
+            ));
+        }
+
+        let mut taken: Vec<String> = self
+            .device_root_nodes(&target_root)?
+            .into_iter()
+            .filter(|n| !n.trashed)
+            .map(|n| n.name)
+            .collect();
+        let synced = self
+            .db
+            .sync_folder_list()
+            .map_err(|e| CoreError::internal(format!("db: {e:?}")))?;
+
+        let mut moved = 0usize;
+        let mut renamed: Vec<String> = Vec::new();
+        let mut left: Vec<String> = Vec::new();
+        let mut failed: Vec<String> = Vec::new();
+        for node in self.device_root_nodes(&source_root)? {
+            if node.trashed || node.name == PROFILE_DIR_NAME {
+                continue;
+            }
+            // A device root only ever holds folders (B68); anything else was
+            // put there by hand and is left for the user to deal with.
+            if !node.is_folder() {
+                left.push(node.name);
+                continue;
+            }
+            let new_name = migrated_name(&node.name, &source.name, &taken);
+            if let Err(e) = self.move_rename_remote(&node.uid, &target_root, new_name.as_deref()) {
+                warn!(name = %node.name, error = %e, "migrate: could not move folder");
+                failed.push(format!("{}: {e}", node.name));
+                continue;
+            }
+            let landed = new_name.clone().unwrap_or_else(|| node.name.clone());
+            if new_name.is_some() {
+                renamed.push(format!("{} -> {landed}", node.name));
+            }
+            taken.push(landed);
+            moved += 1;
+
+            let uid = node.uid.to_string();
+            for folder in synced.iter().filter(|f| f.remote_uid == uid) {
+                if let Err(e) = self.db.sync_folder_set_share(folder.id, &target.share_id) {
+                    warn!(id = folder.id, error = ?e, "migrate: could not re-point sync folder");
+                }
+                self.sync_now(Some(folder.id));
+            }
+        }
+        self.invalidate_children_of(&source_root);
+        self.invalidate_children_of(&target_root);
+
+        let mut message = format!("moved {moved} folder(s) from {}", source.name);
+        if !renamed.is_empty() {
+            message.push_str(&format!("; renamed: {}", renamed.join(", ")));
+        }
+        if !left.is_empty() {
+            message.push_str(&format!("; left behind: {}", left.join(", ")));
+        }
+        if !failed.is_empty() {
+            message.push_str(&format!("; failed: {}", failed.join(", ")));
+        }
+        info!(from = %source.name, to = %target.name, moved, failed = failed.len(),
+            "device migrated");
+        if moved == 0 && !failed.is_empty() {
+            return Err(CoreError::conflict(message));
+        }
+        Ok(message)
+    }
+
+    // ---- device folder sync -------------------------
 
     /// Auto-register (or recover) this machine as a Proton Drive Device, caching
     /// it so restarts reuse the same device. Recovery matches an existing remote
@@ -270,8 +388,7 @@ impl Core {
     /// Resolution order: the *adopted* uid pinned in `config.json`, then the
     /// cached DB row (validated remotely), then a hostname match, then create.
     /// The pin exists because the hostname heuristic silently registers a second
-    /// device after a rename or reinstall, orphaning the first one's folders
+    /// device after a rename or reinstall, orphaning the first one's folders.
-    /// (features.md 5.1).
     pub(crate) fn ensure_device(&self) -> CoreResult<StoredDevice> {
         let name = this_hostname();
         // Enumerate the remote devices once: used to validate the pin, validate
@@ -361,23 +478,27 @@ impl Core {
         root_uid: &NodeUid,
         name: &str,
     ) -> CoreResult<Option<NodeUid>> {
-        let uids = self
+        Ok(self
-            .rt
+            .device_root_nodes(root_uid)?
-            .block_on(self.client.enumerate_folder_children_node_uids(root_uid))
-            .map_err(|e| CoreError::from_api(&e, "list device root"))?;
-        if uids.is_empty() {
-            return Ok(None);
-        }
-        let nodes = self
-            .rt
-            .block_on(self.client.enumerate_nodes(&uids))
-            .map_err(|e| CoreError::from_api(&e, "resolve device root children"))?;
-        Ok(nodes
             .into_iter()
             .find(|n| n.is_folder() && !n.trashed && n.name == name)
             .map(|n| n.uid))
     }
 
+    /// Everything directly under a device root, trashed nodes included.
+    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))
+            .map_err(|e| CoreError::from_api(&e, "list device root"))?;
+        if uids.is_empty() {
+            return Ok(Vec::new());
+        }
+        self.rt
+            .block_on(self.drive.enumerate_nodes(&uids))
+            .map_err(|e| CoreError::from_api(&e, "resolve device root children"))
+    }
+
     /// Add a local folder to this device's sync set: register the device if
     /// needed, create a matching folder under the device root, upload the local
     /// tree into it once, and record the mapping. Phase 1 is a one-shot upload —
@@ -446,10 +567,7 @@ impl Core {
             }
             None => self
                 .rt
-                .block_on(
+                .block_on(self.drive.create_folder(&root_uid, &name, Some(now_secs())))
-                    self.client
-                        .create_folder(&root_uid, &name, Some(now_secs())),
-                )
                 .map_err(|e| CoreError::from_api(&e, &format!("create device folder {name}")))?,
         };
 
@@ -539,12 +657,16 @@ impl Core {
                     } else {
                         p.total.max(p.done) as u64
                     },
+                    // Most passes find nothing; only one that queues work is
+                    // the drive syncing.
+                    background: true,
                 },
                 SyncPhase::Applying => JobItem {
                     title: format!("Syncing {folder}"),
                     detail: p.current.clone(),
                     done: p.done as u64,
                     total: p.total.max(p.done) as u64,
+                    background: false,
                 },
             });
         }
@@ -603,7 +725,7 @@ impl Core {
             && let Some(uid) = parse_uid(&folder.remote_uid)
             && let Err(e) = self
                 .rt
-                .block_on(self.client.trash_nodes(&[uid]))
+                .block_on(self.drive.trash_nodes(&[uid]))
                 .and_then(batch::into_unit)
         {
             warn!(id, error = %e, "delete remote device folder failed");
@@ -619,23 +741,16 @@ impl Core {
         };
     }
 
-    /// A sibling Core that shares this one's client/rt/cache/db (and transfer,
+    /// A sibling Core for a secondary FUSE session rooted at an `ondemand` sync
-    /// activity, mount registries) but gets a **fresh, empty `State`** — its own
+    /// folder. It shares everything with this one,
-    /// inode space starting at [`ROOT_INO`]. Used to root a secondary FUSE session
+    /// the tree included, except what belongs to a session: its root and its
-    /// at an `ondemand` sync folder without colliding with the main mount's inodes
+    /// kernel channel, both filled in when the session is built.
-    /// (devices.md Phase 3).
     pub(crate) fn fork_state(&self) -> Core {
         let mut fork = self.clone();
         fork.primary = false;
-        let share_access = self.state().share_access.clone();
+        fork.root = Arc::new(OnceLock::new());
-        fork.state = Arc::new(Mutex::new(State::new(self.db.clone(), share_access, 2)));
-        // A fresh inode space needs a fresh notification channel: this fork's
-        // session is the only one that knows these inodes, so it must be the one
-        // notified about them. Filled in by `spawn_ondemand_mount`.
         fork.notifier = Arc::new(OnceLock::new());
         fork.session_live = Arc::new(std::sync::atomic::AtomicBool::new(false));
-        // Size upgrades are keyed by inode, which is per-fork too.
-        fork.size_upgrades = Arc::new(Mutex::new(HashMap::new()));
         fork
     }
 
@@ -853,12 +968,29 @@ impl Core {
                 if folder.state != "idle" {
                     return Err(SwitchBlocked::NotNow);
                 }
+                // `idle` only says the last pass applied everything it tried.
+                // It never tries an ignored path, a symlink or a folder it
+                // cannot read, it defers a file open for writing, and a file can
+                // change after it ends. The eviction below deletes all of those
+                // for good, so it waits until nothing here is missing from Drive
+                // (B198).
+                let baseline = self
+                    .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))
+                {
+                    return Err(SwitchBlocked::Failed(format!(
+                        "going online-only would delete what is only on this computer: {reason}"
+                    )));
+                }
                 let root_uid = parse_uid(&folder.remote_uid).ok_or_else(|| {
                     SwitchBlocked::Failed(format!("bad remote uid: {}", folder.remote_uid))
                 })?;
                 let root = self
                     .rt
-                    .block_on(self.client.enumerate_nodes(std::slice::from_ref(&root_uid)))
+                    .block_on(self.drive.enumerate_nodes(std::slice::from_ref(&root_uid)))
                     .map_err(|e| SwitchBlocked::Failed(format!("fetch remote root: {e}")))?
                     .into_iter()
                     .next()
@@ -937,8 +1069,8 @@ impl Core {
         }
     }
 
-    /// Spawn a secondary FUSE session rooted at `root` over `local` on a forked
+    /// Spawn a secondary FUSE session rooted at `root` over `local` from a
-    /// inode space. Clears any stale kernel mount first (a crashed run can leave
+    /// [`Core::fork_state`] sibling. Clears any stale kernel mount first (a crashed run can leave
     /// one, which would fail the fresh mount with EBUSY).
     pub(crate) fn spawn_ondemand_mount(
         &self,
@@ -996,8 +1128,7 @@ impl Core {
     /// restart (their local dirs are empty on disk — the files live in the cloud).
     /// Best-effort per folder: a missing local path or a failed remote fetch marks
     /// the folder `error` and moves on rather than aborting the rest. Runs on its
-    /// own thread from `mount` so the network fetches never block startup
+    /// own thread from `mount` so the network fetches never block startup.
-    /// (devices.md Phase 4).
     pub(crate) fn restore_ondemand_mounts(&self) {
         let folders = match self.db.sync_folder_list() {
             Ok(f) => f,
@@ -1017,7 +1148,7 @@ impl Core {
             };
             let root = match self
                 .rt
-                .block_on(self.client.enumerate_nodes(std::slice::from_ref(&root_uid)))
+                .block_on(self.drive.enumerate_nodes(std::slice::from_ref(&root_uid)))
             {
                 Ok(v) => match v.into_iter().next() {
                     Some(n) => n,
@@ -1119,10 +1250,38 @@ mod tests {
     use pdfs_core::db::StoredSyncFolder;
 
     use super::{
-        ApplicableMountMode, commit_after_teardown, pending_intent_matches,
+        ApplicableMountMode, commit_after_teardown, migrated_name, pending_intent_matches,
         restore_snapshot_matches, select_mode_transition,
     };
 
+    #[test]
+    fn migrated_folder_keeps_its_name_when_it_is_free() {
+        let taken = vec!["Pictures".to_string()];
+        assert_eq!(migrated_name("Documents", "DESKTOP-1", &taken), None);
+    }
+
+    #[test]
+    fn migrated_folder_is_named_after_its_device_on_a_clash() {
+        let taken = vec!["Documents".to_string()];
+        assert_eq!(
+            migrated_name("Documents", "DESKTOP-1", &taken).as_deref(),
+            Some("Documents (DESKTOP-1)")
+        );
+    }
+
+    #[test]
+    fn migrated_folder_is_numbered_when_the_device_name_is_taken_too() {
+        let taken = vec![
+            "Documents".to_string(),
+            "Documents (DESKTOP-1)".to_string(),
+            "Documents (DESKTOP-1) 2".to_string(),
+        ];
+        assert_eq!(
+            migrated_name("Documents", "DESKTOP-1", &taken).as_deref(),
+            Some("Documents (DESKTOP-1) 3")
+        );
+    }
+
     #[test]
     fn unknown_mode_cannot_select_a_destructive_transition() {
         let mut unmounts = 0;

crates/pdfs-fuse/src/drive.rs

@@ -0,0 +1,473 @@
+//! The calls the sync core makes to Drive, behind a trait.
+//!
+//! `Core` used to hold a concrete [`ProtonDriveClient`], so no test could make
+//! Drive answer late, answer stale, or not answer at all, and the interleavings
+//! behind most recent bugs could only be found on a real account over a slow
+//! link. [`DriveApi`] is the part of the
+//! client the mount, the drain, the event feed and the mirror engine use; the
+//! 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.
+//!
+//! 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
+//! of any type) cannot be part of an object-safe trait, so the trait takes them
+//! as trait objects and `impl dyn DriveApi` puts the generic signatures back.
+
+use std::io::{Read, Write};
+use std::sync::Arc;
+
+use async_trait::async_trait;
+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::{
+    DriveEvent, DriveEventScopeId, Node, NodeMoveItem, ProtonDriveClient, RevisionReader, Thumbnail,
+};
+
+/// One outcome per node of a batch request; see [`ProtonDriveClient::trash_nodes`].
+pub(crate) type NodeOutcomes = Vec<(NodeUid, Result<()>)>;
+
+/// The outcomes of a streaming batch request, one item per node as it lands.
+pub(crate) type OutcomeStream<'a> = BoxStream<'a, Result<(NodeUid, Result<()>)>>;
+
+/// Drive as the sync core sees it. See the module documentation.
+#[async_trait]
+pub(crate) trait DriveApi: Send + Sync {
+    async fn get_my_files_folder(&self) -> Result<Node>;
+
+    async fn get_node(&self, uid: &NodeUid) -> Result<Option<Node>>;
+
+    async fn enumerate_nodes(&self, uids: &[NodeUid]) -> Result<Vec<Node>>;
+
+    /// As [`DriveApi::enumerate_nodes`], but files carry no claimed size or
+    /// modification time; see [`ProtonDriveClient::enumerate_nodes_light`].
+    async fn enumerate_nodes_light(&self, uids: &[NodeUid]) -> Result<Vec<Node>>;
+
+    async fn enumerate_folder_children_node_uids(
+        &self,
+        folder_uid: &NodeUid,
+    ) -> Result<Vec<NodeUid>>;
+
+    async fn enumerate_events(
+        &self,
+        scope: &DriveEventScopeId,
+        cursor: Option<&DriveEventId>,
+    ) -> Result<Vec<DriveEvent>>;
+
+    async fn invalidate_caches_for_event(&self, event: &DriveEvent) -> Result<()>;
+
+    async fn create_folder(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        last_modification_time: Option<i64>,
+    ) -> Result<NodeUid>;
+
+    async fn upload_file(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        contents: &[u8],
+    ) -> Result<NodeUid>;
+
+    #[allow(clippy::too_many_arguments)]
+    async fn upload_file_from_dyn(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        reader: &mut (dyn Read + Send),
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+        aead: bool,
+    ) -> Result<NodeUid>;
+
+    #[allow(clippy::too_many_arguments)]
+    async fn upload_file_replacing_draft_from_dyn(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        reader: &mut (dyn Read + Send),
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+        aead: bool,
+    ) -> Result<NodeUid>;
+
+    async fn upload_new_revision_from_dyn(
+        &self,
+        file_uid: &NodeUid,
+        reader: &mut (dyn Read + Send),
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+    ) -> Result<()>;
+
+    async fn open_revision(&self, uid: &NodeUid) -> Result<Arc<dyn RevisionRead>>;
+
+    async fn download_file_to_dyn(
+        &self,
+        uid: &NodeUid,
+        output: &mut (dyn Write + Send),
+    ) -> Result<()>;
+
+    async fn download_revision_to_dyn(
+        &self,
+        file_uid: &NodeUid,
+        revision_id: &str,
+        writer: &mut (dyn Write + Send),
+    ) -> Result<()>;
+
+    async fn rename_node(
+        &self,
+        uid: &NodeUid,
+        new_name: &str,
+        new_media_type: Option<&str>,
+    ) -> Result<()>;
+
+    async fn move_node(&self, uid: &NodeUid, new_parent: &NodeUid) -> Result<()>;
+
+    fn move_nodes_streaming<'a>(
+        &'a self,
+        items: Vec<NodeMoveItem>,
+        new_parent: NodeUid,
+    ) -> OutcomeStream<'a>;
+
+    async fn trash_nodes(&self, uids: &[NodeUid]) -> Result<NodeOutcomes>;
+
+    async fn restore_nodes(&self, uids: &[NodeUid]) -> Result<NodeOutcomes>;
+
+    fn restore_nodes_streaming<'a>(&'a self, uids: &[NodeUid]) -> OutcomeStream<'a>;
+
+    fn delete_nodes_streaming<'a>(&'a self, uids: &[NodeUid]) -> OutcomeStream<'a>;
+
+    async fn enumerate_trash_node_uids(&self) -> Result<Vec<NodeUid>>;
+
+    /// The account's storage, across every Proton product.
+    async fn quota(&self) -> Result<Quota>;
+
+    /// 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
+    /// worker it is called on.
+    #[cfg(test)]
+    fn landing(&self, _uid: &NodeUid) {}
+}
+
+/// The generic signatures of the client, over the object-safe ones above.
+impl dyn DriveApi {
+    #[allow(clippy::too_many_arguments)]
+    pub(crate) async fn upload_file_from<R: Read + Send>(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        mut reader: R,
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+        aead: bool,
+    ) -> Result<NodeUid> {
+        self.upload_file_from_dyn(
+            parent_uid,
+            name,
+            media_type,
+            &mut reader,
+            intended_size,
+            thumbnails,
+            last_modification_time,
+            aead,
+        )
+        .await
+    }
+
+    #[allow(clippy::too_many_arguments)]
+    pub(crate) async fn upload_file_replacing_draft_from<R: Read + Send>(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        mut reader: R,
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+        aead: bool,
+    ) -> Result<NodeUid> {
+        self.upload_file_replacing_draft_from_dyn(
+            parent_uid,
+            name,
+            media_type,
+            &mut reader,
+            intended_size,
+            thumbnails,
+            last_modification_time,
+            aead,
+        )
+        .await
+    }
+
+    pub(crate) async fn upload_new_revision_from<R: Read + Send>(
+        &self,
+        file_uid: &NodeUid,
+        mut reader: R,
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+    ) -> Result<()> {
+        self.upload_new_revision_from_dyn(
+            file_uid,
+            &mut reader,
+            intended_size,
+            thumbnails,
+            last_modification_time,
+        )
+        .await
+    }
+
+    pub(crate) async fn download_file_to<W: Write + Send>(
+        &self,
+        uid: &NodeUid,
+        output: &mut W,
+    ) -> Result<()> {
+        self.download_file_to_dyn(uid, output).await
+    }
+
+    pub(crate) async fn download_revision_to<W: Write + Send>(
+        &self,
+        file_uid: &NodeUid,
+        revision_id: &str,
+        writer: &mut W,
+    ) -> Result<()> {
+        self.download_revision_to_dyn(file_uid, revision_id, writer)
+            .await
+    }
+}
+
+/// An open revision that block reads are served from; see [`RevisionReader`].
+#[async_trait]
+pub(crate) trait RevisionRead: Send + Sync {
+    /// Plaintext size of the revision.
+    fn size(&self) -> u64;
+
+    /// Plaintext size of each block, in block order.
+    fn block_sizes(&self) -> &[u64];
+
+    async fn read_at(&self, offset: u64, length: u64) -> Result<Vec<u8>>;
+}
+
+#[async_trait]
+impl RevisionRead for RevisionReader {
+    fn size(&self) -> u64 {
+        RevisionReader::size(self)
+    }
+
+    fn block_sizes(&self) -> &[u64] {
+        RevisionReader::block_sizes(self)
+    }
+
+    async fn read_at(&self, offset: u64, length: u64) -> Result<Vec<u8>> {
+        RevisionReader::read_at(self, offset, length).await
+    }
+}
+
+#[async_trait]
+impl DriveApi for ProtonDriveClient {
+    async fn get_my_files_folder(&self) -> Result<Node> {
+        ProtonDriveClient::get_my_files_folder(self).await
+    }
+
+    async fn get_node(&self, uid: &NodeUid) -> Result<Option<Node>> {
+        ProtonDriveClient::get_node(self, uid).await
+    }
+
+    async fn enumerate_nodes(&self, uids: &[NodeUid]) -> Result<Vec<Node>> {
+        ProtonDriveClient::enumerate_nodes(self, uids).await
+    }
+
+    async fn enumerate_nodes_light(&self, uids: &[NodeUid]) -> Result<Vec<Node>> {
+        ProtonDriveClient::enumerate_nodes_light(self, uids).await
+    }
+
+    async fn enumerate_folder_children_node_uids(
+        &self,
+        folder_uid: &NodeUid,
+    ) -> Result<Vec<NodeUid>> {
+        ProtonDriveClient::enumerate_folder_children_node_uids(self, folder_uid).await
+    }
+
+    async fn enumerate_events(
+        &self,
+        scope: &DriveEventScopeId,
+        cursor: Option<&DriveEventId>,
+    ) -> Result<Vec<DriveEvent>> {
+        ProtonDriveClient::enumerate_events(self, scope, cursor).await
+    }
+
+    async fn invalidate_caches_for_event(&self, event: &DriveEvent) -> Result<()> {
+        ProtonDriveClient::invalidate_caches_for_event(self, event).await
+    }
+
+    async fn create_folder(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        last_modification_time: Option<i64>,
+    ) -> Result<NodeUid> {
+        ProtonDriveClient::create_folder(self, parent_uid, name, last_modification_time).await
+    }
+
+    async fn upload_file(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        contents: &[u8],
+    ) -> Result<NodeUid> {
+        ProtonDriveClient::upload_file(self, parent_uid, name, media_type, contents).await
+    }
+
+    async fn upload_file_from_dyn(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        reader: &mut (dyn Read + Send),
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+        aead: bool,
+    ) -> Result<NodeUid> {
+        ProtonDriveClient::upload_file_from(
+            self,
+            parent_uid,
+            name,
+            media_type,
+            reader,
+            intended_size,
+            thumbnails,
+            last_modification_time,
+            aead,
+        )
+        .await
+    }
+
+    async fn upload_file_replacing_draft_from_dyn(
+        &self,
+        parent_uid: &NodeUid,
+        name: &str,
+        media_type: &str,
+        reader: &mut (dyn Read + Send),
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+        aead: bool,
+    ) -> Result<NodeUid> {
+        ProtonDriveClient::upload_file_replacing_draft_from(
+            self,
+            parent_uid,
+            name,
+            media_type,
+            reader,
+            intended_size,
+            thumbnails,
+            last_modification_time,
+            aead,
+        )
+        .await
+    }
+
+    async fn upload_new_revision_from_dyn(
+        &self,
+        file_uid: &NodeUid,
+        reader: &mut (dyn Read + Send),
+        intended_size: i64,
+        thumbnails: Vec<Thumbnail>,
+        last_modification_time: Option<i64>,
+    ) -> Result<()> {
+        ProtonDriveClient::upload_new_revision_from(
+            self,
+            file_uid,
+            reader,
+            intended_size,
+            thumbnails,
+            last_modification_time,
+        )
+        .await
+    }
+
+    async fn open_revision(&self, uid: &NodeUid) -> Result<Arc<dyn RevisionRead>> {
+        let reader = ProtonDriveClient::open_revision(self, uid).await?;
+        Ok(Arc::new(reader))
+    }
+
+    async fn download_file_to_dyn(
+        &self,
+        uid: &NodeUid,
+        output: &mut (dyn Write + Send),
+    ) -> Result<()> {
+        ProtonDriveClient::download_file_to(self, uid, &mut &mut *output).await
+    }
+
+    async fn download_revision_to_dyn(
+        &self,
+        file_uid: &NodeUid,
+        revision_id: &str,
+        writer: &mut (dyn Write + Send),
+    ) -> Result<()> {
+        ProtonDriveClient::download_revision_to(self, file_uid, revision_id, &mut &mut *writer)
+            .await
+    }
+
+    async fn rename_node(
+        &self,
+        uid: &NodeUid,
+        new_name: &str,
+        new_media_type: Option<&str>,
+    ) -> Result<()> {
+        ProtonDriveClient::rename_node(self, uid, new_name, new_media_type).await
+    }
+
+    async fn move_node(&self, uid: &NodeUid, new_parent: &NodeUid) -> Result<()> {
+        ProtonDriveClient::move_node(self, uid, new_parent).await
+    }
+
+    fn move_nodes_streaming<'a>(
+        &'a self,
+        items: Vec<NodeMoveItem>,
+        new_parent: NodeUid,
+    ) -> OutcomeStream<'a> {
+        ProtonDriveClient::move_nodes_streaming(self, items, new_parent).boxed()
+    }
+
+    async fn trash_nodes(&self, uids: &[NodeUid]) -> Result<NodeOutcomes> {
+        ProtonDriveClient::trash_nodes(self, uids).await
+    }
+
+    async fn restore_nodes(&self, uids: &[NodeUid]) -> Result<NodeOutcomes> {
+        ProtonDriveClient::restore_nodes(self, uids).await
+    }
+
+    fn restore_nodes_streaming<'a>(&'a self, uids: &[NodeUid]) -> OutcomeStream<'a> {
+        ProtonDriveClient::restore_nodes_streaming(self, uids).boxed()
+    }
+
+    fn delete_nodes_streaming<'a>(&'a self, uids: &[NodeUid]) -> OutcomeStream<'a> {
+        ProtonDriveClient::delete_nodes_streaming(self, uids).boxed()
+    }
+
+    async fn enumerate_trash_node_uids(&self) -> Result<Vec<NodeUid>> {
+        ProtonDriveClient::enumerate_trash_node_uids(self).await
+    }
+
+    async fn quota(&self) -> Result<Quota> {
+        ProtonDriveClient::quota(self).await
+    }
+}

crates/pdfs-fuse/src/events.rs

@@ -9,7 +9,7 @@
 //! through one place (the status, transfers, sync progress) and publishes them
 //! when they differ.
 
-use std::collections::BTreeSet;
+use std::collections::{BTreeSet, HashMap};
 use std::sync::Arc;
 use std::time::Duration;
 
@@ -153,13 +153,15 @@ pub(crate) fn transfers_line(items: Vec<TransferItem>, jobs: Vec<JobItem>) -> Op
 
 /// Watch what changes without a single place to publish it from, and publish it
 /// when it differs from the last look: the status (queue counts, cache use,
-/// online, pause), the transfers snapshot, and the synced folders with their
+/// online, pause), the transfers snapshot, the synced folders with their
-/// live progress. Looks only while someone is subscribed.
+/// live progress, and which nodes have a sync issue. Looks only while someone
+/// is subscribed.
 pub(crate) fn run_event_sampler(core: Core, username: String, mountpoint: std::path::PathBuf) {
     let mut transfers: Option<Arc<str>> = None;
     let mut status: Option<String> = None;
     let mut queue: Option<String> = None;
     let mut locations: Option<String> = None;
+    let mut issues: Option<HashMap<i64, String>> = None;
     let mut tick = 0u32;
     while core.shutdown.sleep(SAMPLE_INTERVAL) {
         if !core.events.has_subscribers() {
@@ -169,6 +171,7 @@ pub(crate) fn run_event_sampler(core: Core, username: String, mountpoint: std::p
             status = None;
             queue = None;
             locations = None;
+            issues = None;
             continue;
         }
         let line = transfers_line(core.transfers.snapshot(), core.jobs_snapshot());
@@ -196,6 +199,15 @@ pub(crate) fn run_event_sampler(core: Core, username: String, mountpoint: std::p
         }
         queue = Some(queue_key);
 
+        // An issue shows on its node in the file browser: raised, cleared,
+        // landed or discarded, the listing is out of date.
+        if let Ok(now) = core.db.node_issues() {
+            if issues.as_ref().is_some_and(|last| *last != now) {
+                core.events.publish(&[Topic::Files]);
+            }
+            issues = Some(now);
+        }
+
         if let Ok(now) = core.list_locations() {
             let key = serde_json::to_string(&now).unwrap_or_default();
             if locations.as_ref().is_some_and(|last| *last != key) {
@@ -223,6 +235,8 @@ fn status_keys(status: &CtlResponse) -> (String, String) {
         used,
         budget,
         online,
+        session_expired,
+        tokens_unsaved,
         pending_uploads,
         pending_changes,
         ..
@@ -235,7 +249,7 @@ fn status_keys(status: &CtlResponse) -> (String, String) {
     );
     let key = format!(
         "{queue}/{staged_bytes}/{paused}/{paused_until:?}/{username}/{mountpoint}/{pinned}/\
-         {used}/{budget}/{online}"
+         {used}/{budget}/{online}/{session_expired}/{tokens_unsaved}"
     );
     (key, queue)
 }
@@ -313,6 +327,8 @@ mod tests {
             budget: 0,
             pins: Vec::new(),
             online: true,
+            session_expired: false,
+            tokens_unsaved: false,
             pending_uploads: 1,
             pending_changes: 0,
         };

crates/pdfs-fuse/src/filesystem.rs

@@ -72,7 +72,7 @@ impl Filesystem for ProtonFs {
     }
 
     fn lookup(&self, _req: &Request, parent: INodeNo, name: &OsStr, reply: ReplyEntry) {
-        let parent = parent.0;
+        let parent = self.tree(parent).0;
         let name = match fuse_name(name) {
             Ok(name) => name,
             Err(error) => {
@@ -95,11 +95,13 @@ impl Filesystem for ProtonFs {
     }
 
     fn forget(&self, _req: &Request, ino: INodeNo, nlookup: u64) {
+        let ino = self.tree(ino);
         let mut st = self.core.state();
         st.forget_lookup(ino.0, nlookup);
     }
 
     fn getattr(&self, _req: &Request, ino: INodeNo, _fh: Option<FileHandle>, reply: ReplyAttr) {
+        let ino = self.tree(ino);
         let (attr, provisional_in) = {
             let st = self.core.state();
             match st.entries.get(&ino.0) {
@@ -130,7 +132,7 @@ impl Filesystem for ProtonFs {
         // A provisional size is the *ciphertext* size, which is larger than the
         // file. Publishing it makes every reader that trusts `st_size` — rsync,
         // mmap, sendfile, a sized read loop — run off the end of the file and
-        // fail. So resolve it before answering rather than after (bugs.md B14).
+        // fail. So resolve it before answering rather than after (`docs/BUGS.md` B14).
         //
         // The cost is one batched round trip for the whole folder, not one per
         // file: `ls -l` is one `getattr` per entry and they collapse onto a
@@ -170,12 +172,12 @@ impl Filesystem for ProtonFs {
     /// here — once per `opendir`, which the kernel pairs exactly with one
     /// `releasedir` — is what makes the offsets stable, so a create or a trash
     /// during an enumeration can no longer make the caller skip or repeat an
-    /// entry (bugs.md B43).
+    /// entry (`docs/BUGS.md` B43).
     ///
     /// Enumerating a cold folder is a remote call, so it goes to a worker for
     /// the same reason `lookup` and `readdir` do.
     fn opendir(&self, _req: &Request, ino: INodeNo, _flags: OpenFlags, reply: ReplyOpen) {
-        let ino = ino.0;
+        let ino = self.tree(ino).0;
         if self.core.children_cached(ino) {
             self.serve_opendir(ino, reply);
             return;
@@ -194,13 +196,13 @@ impl Filesystem for ProtonFs {
         offset: u64,
         reply: ReplyDirectory,
     ) {
-        let ino = ino.0;
+        let ino = self.tree(ino).0;
         // The snapshot is the whole point: served from it, this is a pure
         // in-memory walk with no chance of a remote call, so it never needs a
         // worker. Only a handle whose `opendir` failed to snapshot (or a kernel
         // that issued `readdir` without one) falls back to the live path.
         if let Some(listing) = self.core.state().dir_snapshots.get(&fh.0).cloned() {
-            reply_listing(&listing, offset, reply);
+            reply_listing(&listing, offset, self.root, reply);
             return;
         }
         // Same split as `lookup`: only the cold, remote-enumerating path pays
@@ -232,6 +234,7 @@ impl Filesystem for ProtonFs {
     /// a blob that is the whole file — so it is served from a worker rather than
     /// stalling every other request on the mount behind it.
     fn open(&self, _req: &Request, ino: INodeNo, flags: OpenFlags, reply: ReplyOpen) {
+        let ino = self.tree(ino);
         if flags.acc_mode() == OpenAccMode::O_RDONLY {
             self.serve_open(ino, flags, reply);
             return;
@@ -253,6 +256,7 @@ impl Filesystem for ProtonFs {
         _lock_owner: Option<LockOwner>,
         reply: ReplyData,
     ) {
+        let ino = self.tree(ino);
         // A file open for writing is served from its handle so reads see the
         // in-flight (possibly unsaved) content: authored bytes come from the
         // scratch file, untouched bytes from the base.
@@ -342,7 +346,7 @@ impl Filesystem for ProtonFs {
         self.core.workers.run(Lane::Transfer, "read", move || {
             // The revision disagrees with a provisional size, and B84 fails
             // such a read outright, so settle the size first. On the network,
-            // hence here and not above (bugs.md B100).
+            // hence here and not above (`docs/BUGS.md` B100).
             let fsize = match provisional {
                 true => core.resolve_provisional_size(ino.0, &uid).unwrap_or(fsize),
                 false => fsize,
@@ -364,7 +368,7 @@ impl Filesystem for ProtonFs {
         _flags: i32,
         reply: ReplyCreate,
     ) {
-        let parent = parent.0;
+        let parent = self.tree(parent).0;
         if let Err(error) = self.core.require_writable(parent) {
             reply.error(error);
             return;
@@ -400,6 +404,7 @@ impl Filesystem for ProtonFs {
         _lock_owner: Option<LockOwner>,
         reply: ReplyWrite,
     ) {
+        let ino = self.tree(ino);
         if let Err(error) = self.core.require_writable(ino.0) {
             reply.error(error);
             return;
@@ -477,6 +482,7 @@ impl Filesystem for ProtonFs {
         _flags: Option<BsdFileFlags>,
         reply: ReplyAttr,
     ) {
+        let ino = self.tree(ino);
         if let Err(error) = self.core.require_writable(ino.0) {
             reply.error(error);
             return;
@@ -511,7 +517,7 @@ impl Filesystem for ProtonFs {
                 // `> file`. This is the second write path into the API, and
                 // queueing it is what lets a redirect work offline at all: it
                 // never reaches `release`, so without this it failed before any
-                // byte was written (offline.md Phase 2/3b).
+                // byte was written.
                 //
                 // The one branch of `setattr` that can reach the network:
                 // shrinking keeps the prefix, which `queue_truncate` gap-fills
@@ -544,6 +550,7 @@ impl Filesystem for ProtonFs {
         mode: i32,
         reply: ReplyEmpty,
     ) {
+        let ino = self.tree(ino);
         if let Err(error) = self.core.require_writable(ino.0) {
             reply.error(error);
             return;
@@ -600,7 +607,7 @@ impl Filesystem for ProtonFs {
     }
 
     /// `close(2)` calls flush before release. The upload is queued in `release`
-    /// and performed in the background (offline.md Phase 3), so there is nothing
+    /// and performed in the background, so there is nothing
     /// to push here — the written bytes are already in the scratch file.
     fn flush(
         &self,
@@ -640,16 +647,17 @@ impl Filesystem for ProtonFs {
     fn release(
         &self,
         _req: &Request,
-        _ino: INodeNo,
+        ino: INodeNo,
         fh: FileHandle,
         _flags: OpenFlags,
         _lock_owner: Option<LockOwner>,
         _flush: bool,
         reply: ReplyEmpty,
     ) {
+        let ino = self.tree(ino);
         let (handle, unlinked_uid) = {
             let mut st = self.core.state();
-            let unlinked_uid = release_unlinked_entry(&mut st, _ino.0);
+            let unlinked_uid = release_unlinked_entry(&mut st, ino.0);
             let ino = st.handles.remove(&fh.0);
             let h = ino.and_then(|i| {
                 let aw = st.active_writes.get_mut(&i)?;
@@ -680,7 +688,7 @@ impl Filesystem for ProtonFs {
     }
 
     fn unlink(&self, _req: &Request, parent: INodeNo, name: &OsStr, reply: ReplyEmpty) {
-        let parent = parent.0;
+        let parent = self.tree(parent).0;
         if let Err(error) = self.core.require_writable(parent) {
             reply.error(error);
             return;
@@ -700,7 +708,7 @@ impl Filesystem for ProtonFs {
     }
 
     fn rmdir(&self, _req: &Request, parent: INodeNo, name: &OsStr, reply: ReplyEmpty) {
-        let parent = parent.0;
+        let parent = self.tree(parent).0;
         if let Err(error) = self.core.require_writable(parent) {
             reply.error(error);
             return;
@@ -729,7 +737,7 @@ impl Filesystem for ProtonFs {
         _umask: u32,
         reply: ReplyEntry,
     ) {
-        let parent = parent.0;
+        let parent = self.tree(parent).0;
         if let Err(error) = self.core.require_writable(parent) {
             reply.error(error);
             return;
@@ -760,8 +768,8 @@ impl Filesystem for ProtonFs {
         flags: RenameFlags,
         reply: ReplyEmpty,
     ) {
-        let parent = parent.0;
+        let parent = self.tree(parent).0;
-        let newparent = newparent.0;
+        let newparent = self.tree(newparent).0;
         if let Err(error) = self
             .core
             .require_writable(parent)
@@ -794,6 +802,7 @@ impl Filesystem for ProtonFs {
     }
 
     fn access(&self, _req: &Request, ino: INodeNo, mask: AccessFlags, reply: ReplyEmpty) {
+        let ino = self.tree(ino);
         let state = self.core.state();
         let Some(entry) = state.entries.get(&ino.0) else {
             reply.error(Errno::ENOENT);
@@ -807,6 +816,7 @@ impl Filesystem for ProtonFs {
     }
 
     fn getxattr(&self, _req: &Request, ino: INodeNo, name: &OsStr, size: u32, reply: ReplyXattr) {
+        let ino = self.tree(ino);
         // Always off the dispatch loop: a miss goes to the wire, and a lister
         // that stats a directory issues one of these per file per advertised
         // name — inline, that serialized the whole mount behind ~186 ms of
@@ -819,6 +829,7 @@ impl Filesystem for ProtonFs {
     }
 
     fn listxattr(&self, _req: &Request, ino: INodeNo, size: u32, reply: ReplyXattr) {
+        let ino = self.tree(ino);
         self.serve_listxattr(ino, size, reply);
     }
 
@@ -968,10 +979,13 @@ pub struct ProtonFs {
     core: Core,
     uid: u32,
     gid: u32,
+    /// The tree inode of this session's root, which the kernel knows as
+    /// [`ROOT_INO`].
+    root: u64,
 }
 
 /// How many times a write `open` will re-read its base after a `release`
-/// published a newer queued revision underneath it (bugs.md B32).
+/// published a newer queued revision underneath it (`docs/BUGS.md` B32).
 ///
 /// One retry covers the race, which needs a close and an open of the same file
 /// to overlap on different threads. More than that is not contention, it is a
@@ -1007,60 +1021,56 @@ 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 (bugs.md B43).
+/// the listing behind those indexes is a snapshot (`docs/BUGS.md` B43).
-fn reply_listing(listing: &DirListing, offset: u64, mut reply: ReplyDirectory) {
+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 {
             FileType::Directory
         } else {
             FileType::RegularFile
         };
-        if reply.add(INodeNo(*ino), (i + 1) as u64, ft, name) {
+        if reply.add(kernel_ino(root, *ino), (i + 1) as u64, ft, name) {
             break;
         }
     }
     reply.ok();
 }
 
+/// The inode the kernel knows tree inode `ino` by, in a session rooted at
+/// `root`. The inverse of [`ProtonFs::tree`].
+pub(crate) fn kernel_ino(root: u64, ino: u64) -> INodeNo {
+    INodeNo(if ino == root { ROOT_INO } else { ino })
+}
+
 pub(crate) fn access_allowed(is_dir: bool, access: Access, mask: AccessFlags) -> bool {
     (!mask.contains(AccessFlags::W_OK) || access.writable())
         && (!mask.contains(AccessFlags::X_OK) || is_dir)
 }
 
 impl ProtonFs {
-    /// Build the filesystem rooted at `root` (the user's My Files folder).
+    /// Build the filesystem rooted at `root` (the user's My Files folder, or
+    /// the folder an on-demand location shows).
     pub(super) fn new(core: Core, root: Node) -> Self {
-        {
+        let root = core.state().install_root(root);
-            let mut st = core.state();
+        let _ = core.root.set(root);
-            if let Err(e) = st.db.upsert_node(&root) {
-                warn!(uid = %root.uid, error = %e, "db upsert root failed");
-            }
-            st.by_uid.insert(root.uid.clone(), ROOT_INO);
-            // The filesystem root is always owned — it must never be
-            // classified as a shared root, even when the API returns
-            // membership data (which happens when the owner shares the
-            // folder with someone else).  Clean up any stale share_access
-            // row that a previous downgrade_all_share_access may have
-            // written for this uid, so hydrate_access cannot pick it up.
-            let access = Access::Owner;
-            st.share_access.remove(&root.uid);
-            let _ = st.db.delete_share_access(&root.uid);
-            st.entries.insert(
-                ROOT_INO,
-                Entry {
-                    uid: root.uid.clone(),
-                    parent: ROOT_INO,
-                    node: root,
-                    access,
-                    lookup_count: 1,
-                    open_count: 0,
-                    unlinked: false,
-                },
-            );
-        }
         // SAFETY: geteuid/getegid are infallible and have no preconditions.
         let (uid, gid) = unsafe { (libc::geteuid(), libc::getegid()) };
-        Self { core, uid, gid }
+        Self {
+            core,
+            uid,
+            gid,
+            root,
+        }
+    }
+
+    /// The tree inode the kernel means by `ino`: this session's root for
+    /// [`ROOT_INO`], and every other inode as it is.
+    fn tree(&self, ino: INodeNo) -> INodeNo {
+        if ino.0 == ROOT_INO {
+            INodeNo(self.root)
+        } else {
+            ino
+        }
     }
 
     /// The body of [`Filesystem::lookup`], on whichever thread ends up serving it.
@@ -1084,7 +1094,7 @@ impl ProtonFs {
                             // `getattr` would, so `ls -l` — which is one `lookup`
                             // per entry and no `getattr` at all — takes its sizes
                             // from here. Resolving only in `getattr` left the whole
-                            // listing provisional (bugs.md B14).
+                            // listing provisional (`docs/BUGS.md` B14).
                             let provisional = matches!(
                                 &e.node.kind,
                                 NodeKind::File {
@@ -1169,7 +1179,7 @@ impl ProtonFs {
         let st = self.core.state();
         let listing = build_listing(&st, ino);
         drop(st);
-        reply_listing(&listing, offset, reply);
+        reply_listing(&listing, offset, self.root, reply);
     }
 
     fn attr(&self, ino: u64, node: &Node, access: Access) -> FileAttr {
@@ -1182,7 +1192,7 @@ impl ProtonFs {
         let mtime = unix_secs(node.modification_time);
         let crtime = unix_secs(node.creation_time);
         FileAttr {
-            ino: INodeNo(ino),
+            ino: kernel_ino(self.root, ino),
             size,
             blocks: size.div_ceil(512),
             atime: mtime,
@@ -1207,7 +1217,7 @@ impl ProtonFs {
     /// open.
     fn serve_open(&self, ino: INodeNo, flags: OpenFlags, reply: ReplyOpen) {
         let write_requested = flags.acc_mode() != OpenAccMode::O_RDONLY;
-        let (uid, base_mtime, base_size, provisional, base_revision_id) = {
+        let (uid, mut base_mtime, mut base_size, mut provisional, mut base_revision_id) = {
             let mut st = self.core.state();
             match st.entries.get_mut(&ino.0) {
                 Some(e) if e.node.is_file() => {
@@ -1257,8 +1267,12 @@ impl ProtonFs {
         //
         // Complete pending blobs are the common case and can be copied without
         // any network access. An incomplete blob still has gaps referring to
-        // the remote base; stacking another write on it cannot be represented
+        // the remote base, and stacking another write on it cannot be
-        // safely by WriteHandle, so fail the open rather than risk corruption.
+        // represented by WriteHandle, so the copy's gaps are filled from that
+        // base first, as the drain fills them before an upload. Only when that
+        // fails (offline, or the base is gone) does the open fail: refusing
+        // every such open failed a create over a file whose partial edit had
+        // not drained yet (`docs/BUGS.md` B204).
         //
         // Reading that blob and installing the handle cannot be done under one
         // lock — the copy is the size of the file — so the base is re-checked at
@@ -1266,34 +1280,32 @@ impl ProtonFs {
         // revision in between sends this around again. Without the re-check the
         // new handle carried the *older* base, and its own release published
         // content that silently discarded the revision closed a moment earlier
-        // (bugs.md B32). A second attempt is already unlikely and a third would
+        // (`docs/BUGS.md` B32). A second attempt is already unlikely and a third would
         // mean something is republishing continuously, so give up rather than
         // spin: the caller's `open` fails instead of its data being lost.
         //
         // `reply` is consumed by whichever arm answers, so the loop yields an
         // outcome and the answer is sent once, after it.
         let outcome = 'install: {
-            // The handle starts at the base's size. A provisional one is the
-            // ciphertext size, so the file would grow by the encryption overhead
-            // and reading the base would fail (bugs.md B100). A queued revision
-            // stamps a real size, so this only goes to the network for a file
-            // the listing has not sized yet.
-            let base_size = match provisional && self.core.pending_blob(&uid).is_none() {
-                false => base_size,
-                true => match self.core.resolve_provisional_size(ino.0, &uid) {
-                    Some(size) => size,
-                    None => {
-                        error!(%uid, "could not settle the size of the base for a write open");
-                        break 'install Err(Errno::EIO);
-                    }
-                },
-            };
             for attempt in 0..OPEN_BASE_ATTEMPTS {
-                let pending_base = self.core.pending.lock().get(&uid).cloned();
+                // The handle starts at the base's size. A provisional one is the
-                if pending_base.as_ref().is_some_and(|p| !p.meta.complete) {
+                // ciphertext size, so the file would grow by the encryption
-                    error!(%uid, "refusing write over incomplete queued revision");
+                // overhead and reading the base would fail (`docs/BUGS.md` B100). A
-                    break 'install Err(Errno::EIO);
+                // queued revision stamps a real size, so this only goes to the
+                // network for a file the listing has not sized yet.
+                if provisional && self.core.pending_blob(&uid).is_none() {
+                    match self.core.resolve_provisional_size(ino.0, &uid) {
+                        Some(size) => {
+                            base_size = size;
+                            provisional = false;
+                        }
+                        None => {
+                            error!(%uid, "could not settle the size of the base for a write open");
+                            break 'install Err(Errno::EIO);
+                        }
+                    }
                 }
+                let pending_base = self.core.pending.lock().get(&uid).cloned();
                 let (file, path) = match self.core.cache.create_scratch() {
                     Ok(x) => x,
                     Err(e) => {
@@ -1313,6 +1325,25 @@ impl ProtonFs {
                             "copy queued revision into write scratch failed");
                         break 'install Err(Errno::EIO);
                     }
+                    if !pending.meta.complete {
+                        let mut authored = Intervals::default();
+                        for &(s, e) in &pending.meta.authored {
+                            authored.add(s, e);
+                        }
+                        if let Err(error) = self.core.fill_gaps(
+                            &uid,
+                            &file,
+                            pending.meta.len,
+                            pending.meta.base_mtime,
+                            pending.meta.base_size,
+                            &authored,
+                        ) {
+                            let _ = std::fs::remove_file(&path);
+                            error!(%uid, ?error, "cannot complete the queued revision a write open is based on");
+                            break 'install Err(error);
+                        }
+                        debug!(%uid, "write open completed an incomplete queued revision");
+                    }
                     initial_written.add(0, pending.meta.len);
                 }
                 // Sampled *before* the state lock, never under it: no site in
@@ -1322,17 +1353,49 @@ impl ProtonFs {
                 // a lock-tight comparison — against the multi-gigabyte copy
                 // above, which is the window that actually loses data.
                 let current = self.core.pending_blob(&uid);
+                let landed = self.core.landed.lock().get(&uid).cloned();
                 let mut st = self.core.state();
                 // Only a handle this open is about to *create* can carry a stale
                 // base; if one already exists, that handle is authoritative and
                 // the scratch prepared above is discarded either way.
                 let creating = !st.active_writes.contains_key(&ino.0);
-                if creating && current != pending_base.map(|p| p.path) {
+                if creating && current.as_ref() != pending_base.as_ref().map(|p| &p.path) {
                     drop(st);
                     let _ = std::fs::remove_file(&path);
                     warn!(%uid, attempt, "queued revision changed while opening for write; retrying");
                     continue;
                 }
+                // With no queued revision, the base's bytes come from the cache,
+                // keyed by the base's mtime and size. The ones sampled above can
+                // name a revision this daemon has since replaced: an upload that
+                // lands lets go of its blob before the tree has its node, and
+                // the cache holds its bytes under the node only. So the base is
+                // the landing node while there is one, and the tree's otherwise
+                // (docs/BUGS.md B170).
+                if creating && pending_base.is_none() {
+                    let now = landed.or_else(|| st.entries.get(&ino.0).map(|e| e.node.clone()));
+                    if let Some(node) = now
+                        && (node.modification_time != base_mtime
+                            || node_revision_id(&node) != base_revision_id)
+                    {
+                        base_mtime = node.modification_time;
+                        base_size = node_size(&node);
+                        base_revision_id = node_revision_id(&node);
+                        provisional = matches!(
+                            &node.kind,
+                            NodeKind::File {
+                                claimed_size: None,
+                                ..
+                            }
+                        );
+                        debug!(%uid, base_mtime, base_size, "write open took the base the file has now");
+                        if provisional {
+                            drop(st);
+                            let _ = std::fs::remove_file(&path);
+                            continue;
+                        }
+                    }
+                }
                 let fh = st.next_fh;
                 st.next_fh += 1;
                 let aw = st.active_writes.entry(ino.0).or_insert_with(|| {
@@ -1435,7 +1498,7 @@ impl ProtonFs {
             len,
             base_size,
             base_mtime,
-            complete: authored == [(0, len)],
+            complete: StagedWrite::covers(&authored, len),
             authored,
             based_on: self
                 .core
@@ -1497,36 +1560,29 @@ impl ProtonFs {
         let transient = is_transient_name(name);
         // Offline the server cannot mint a uid, so invent one and queue the
         // create. The file is real to the caller either way; only its identity is
-        // provisional until the drain (offline.md Phase 3b).
+        // provisional until the drain.
         //
         // A parent that is itself still queued forces the same path even when we
         // are online: the API has no folder to put this in yet.
         //
         // A create that set out online and lost the network on the way lands in
         // the queue too, so a Wi-Fi drop costs the caller a wait, never an EIO.
-        let minted = if !transient && self.core.is_online() && !is_local_uid(&parent_uid) {
+        let minted = if !transient && self.core.sends_inline() && !is_local_uid(&parent_uid) {
             if let Err(error) = self.core.require_uid_writable(&parent_uid) {
                 reply.error(error);
                 return;
             }
             // Create an empty file on the remote so it has a real uid immediately;
             // written bytes are buffered and sealed as a new revision on close.
-            match self.core.block_on_bounded(self.core.client.upload_file(
+            match self.core.block_on_bounded(self.core.drive.upload_file(
                 &parent_uid,
                 name,
                 media_type_for(name),
                 b"",
             )) {
-                Ok(new_uid) => match self.core.fetch_node(&new_uid) {
+                // A file that exists remotely but could not be read back is
-                    Ok(n) => Some(n),
+                // queued, and the queued create finds it by name and adopts it.
-                    // The file exists remotely but we could not read it back.
+                Ok(new_uid) => self.core.fetch_minted_node(&new_uid, name),
-                    // The queued create finds it by name and adopts it.
-                    Err(e) if e == Errno::EIO && !self.core.is_online() => None,
-                    Err(e) => {
-                        reply.error(e);
-                        return;
-                    }
-                },
                 Err(e) if self.core.lost_link(&e, "create") => None,
                 Err(e) => {
                     error!(%parent_uid, name, error = %e, "create file failed");
@@ -1550,26 +1606,16 @@ impl ProtonFs {
                 }
             },
         };
-        let new_uid = node.uid.clone();
-        // The base this handle writes over is the node as it actually exists —
-        // the empty file the server just minted — so its modification time comes
-        // from the node, never from the local clock. `queue_revision` turns this
-        // into `StagedWrite::based_on` and the drain compares that against the
-        // remote: a `now_secs()` here differs from the server's stamp by however
-        // long the create round-trip took, so the first write to a brand-new file
-        // conflicts with its own create whenever the second happens to tick in
-        // between.
-        let base_mtime = node.modification_time;
         let (file, path) = match self.core.cache.create_scratch() {
             Ok(x) => x,
             Err(e) => {
-                error!(%new_uid, error = %e, "create scratch file failed");
+                error!(uid = %node.uid, error = %e, "create scratch file failed");
                 reply.error(Errno::EIO);
                 return;
             }
         };
         let mut st = self.core.state();
-        let ino = st.intern(parent, node);
+        let ino = st.intern(parent, node.clone());
         if let Some(entry) = st.entries.get_mut(&ino) {
             entry.open_count = entry.open_count.saturating_add(1);
         }
@@ -1580,23 +1626,10 @@ impl ProtonFs {
         }
         let fh = st.next_fh;
         st.next_fh += 1;
-        let aw = st.active_writes.entry(ino).or_insert_with(|| {
+        let aw = st
-            // A brand-new file: empty base, everything written is authored.
+            .active_writes
-            WriteHandle {
+            .entry(ino)
-                ino,
+            .or_insert_with(|| WriteHandle::created(ino, &node, file, path));
-                uid: new_uid,
-                file: Arc::new(file),
-                path,
-                written: Intervals::default(),
-                len: 0,
-                base_size: 0,
-                base_mtime,
-                // A brand-new file has no sealed remote revision to conflict with.
-                base_revision_id: None,
-                dirty: false,
-                open_count: 0,
-            }
-        });
         aw.open_count += 1;
         st.handles.insert(fh, ino);
         let entry = st.entries.get(&ino).unwrap();
@@ -1638,25 +1671,18 @@ impl ProtonFs {
             .ok();
         // As in `create`: offline — or under a parent that is itself still
         // queued — the folder becomes a placeholder that the drain turns into a
-        // real one (offline.md Phase 3b).
+        // real one.
         // Losing the network on the way queues it the same way.
-        let minted = if self.core.is_online() && !is_local_uid(&parent_uid) {
+        let minted = if self.core.sends_inline() && !is_local_uid(&parent_uid) {
             if let Err(error) = self.core.require_uid_writable(&parent_uid) {
                 reply.error(error);
                 return;
             }
             match self
                 .core
-                .block_on_bounded(self.core.client.create_folder(&parent_uid, name, now))
+                .block_on_bounded(self.core.drive.create_folder(&parent_uid, name, now))
             {
-                Ok(new_uid) => match self.core.fetch_node(&new_uid) {
+                Ok(new_uid) => self.core.fetch_minted_node(&new_uid, name),
-                    Ok(n) => Some(n),
-                    Err(e) if e == Errno::EIO && !self.core.is_online() => None,
-                    Err(e) => {
-                        reply.error(e);
-                        return;
-                    }
-                },
                 Err(e) if self.core.lost_link(&e, "mkdir") => None,
                 Err(e) => {
                     error!(%parent_uid, name, error = %e, "create folder failed");
@@ -1797,10 +1823,13 @@ impl ProtonFs {
                 self.core.cache.clear_scratch_durable(&h.path);
                 reply.ok();
             }
-            (Some(h), false) => match self.core.queue_revision(&h) {
+            (Some(mut h), false) => {
-                Ok(()) => reply.ok(),
+                self.core.follow_landed_create(&mut h);
-                Err(e) => reply.error(e),
+                match self.core.queue_revision(&mut h) {
-            },
+                    Ok(()) => reply.ok(),
+                    Err(e) => reply.error(e),
+                }
+            }
             (None, _) => reply.ok(),
         }
     }
@@ -1823,7 +1852,7 @@ impl ProtonFs {
             reply.error(error);
             return;
         }
-        let (ino, uid) = match self.core.lookup_child(parent, name) {
+        let (ino, mut uid) = match self.core.lookup_child(parent, name) {
             Ok(x) => x,
             Err(e) => {
                 reply.error(e);
@@ -1864,7 +1893,7 @@ impl ProtonFs {
         // rename, so the victim has to be removed first and the operation stops
         // being atomic. Without this the 422 surfaced as a blanket EIO and every
         // write-to-temp-then-rename tool — rsync, atomic editor saves — failed
-        // at the very end of its transfer (bugs.md B13).
+        // at the very end of its transfer (`docs/BUGS.md` B13).
         //
         // `RENAME_EXCHANGE` has no Proton primitive and cannot be emulated
         // without a window in which one of the two names does not exist.
@@ -1936,7 +1965,7 @@ impl ProtonFs {
                 reply.error(error);
                 return;
             }
-            if let Err(e) = self.core.remove_replaced(victim_uid, newname) {
+            if let Err(e) = self.core.remove_replaced(*victim_ino, victim_uid, newname) {
                 reply.error(e);
                 return;
             }
@@ -1946,8 +1975,9 @@ impl ProtonFs {
         };
         // A node whose own creation is still queued has no server-side identity
         // to rename: the queued op *is* the node, so rewriting its target is the
-        // whole rename. Nothing reaches the API, which is why this works offline
+        // whole rename. Nothing reaches the API, which is why this works offline.
-        // (offline.md Phase 3b).
+        // A create that lands meanwhile leaves no op to rewrite; the node is
+        // then renamed by the uid Drive gave it (docs/BUGS.md B142).
         if is_local_uid(&uid) {
             match self.core.db.rewrite_op_target(
                 &uid.to_string(),
@@ -1958,6 +1988,8 @@ impl ProtonFs {
                     self.core
                         .state()
                         .rename_in_place(ino, newparent, &new_parent_uid, newname);
+                    // A create that failed on its old name is due again.
+                    self.core.wake_drain();
                     // Finalize: a transient scratch file (its create parked, bytes
                     // held back) renamed to a finished name is the moment the
                     // completed file is meant to reach Drive. Un-park the create so
@@ -1976,21 +2008,29 @@ impl ProtonFs {
                     }
                     debug!(%uid, newname, "renamed a node whose create is still queued");
                     reply.ok();
+                    return;
                 }
-                // The create drained underneath us, so the node has a real uid
+                Ok(false) => match self.core.landed_row_uid(ino) {
-                // now and this handle's is stale. A retry resolves it.
+                    Some(real) => {
-                Ok(false) => {
+                        debug!(local = %uid, %real, newname, "create landed under a rename");
-                    warn!(%uid, name, newname, "queued create vanished under a rename");
+                        uid = real;
-                    self.core.restore_replaced(victim.as_ref(), newname);
+                    }
-                    reply.error(Errno::EBUSY);
+                    None => {
-                }
+                        warn!(%uid, name, newname, "queued create vanished under a rename");
+                        self.core
+                            .restore_replaced(victim.as_ref(), &new_parent_uid, newname);
+                        reply.error(Errno::EBUSY);
+                        return;
+                    }
+                },
                 Err(e) => {
                     error!(%uid, error = %e, "rewriting a queued create's target failed");
-                    self.core.restore_replaced(victim.as_ref(), newname);
+                    self.core
+                        .restore_replaced(victim.as_ref(), &new_parent_uid, newname);
                     reply.error(Errno::EIO);
+                    return;
                 }
             }
-            return;
         }
         // Offline, or into a folder that does not exist remotely yet: queue the
         // rename rather than 404 or fail. Online moves into a real parent still
@@ -2029,22 +2069,23 @@ impl ProtonFs {
                     // and retain an empty destination readdir page.
                     reply.ok();
                     if let Some(notifier) = self.core.notifier.get() {
-                        let _ = notifier.inval_entry(INodeNo(parent), OsStr::new(&name));
+                        let _ = notifier.inval_entry(parent, OsStr::new(&name));
-                        let _ = notifier.inval_entry(INodeNo(newparent), OsStr::new(&newname));
+                        let _ = notifier.inval_entry(newparent, OsStr::new(&newname));
-                        let _ = notifier.inval_inode(INodeNo(parent), 0, 0);
+                        let _ = notifier.inval_inode(parent);
                         if newparent != parent {
-                            let _ = notifier.inval_inode(INodeNo(newparent), 0, 0);
+                            let _ = notifier.inval_inode(newparent);
                         }
                     }
                 }
                 Err(e) => {
-                    self.core.restore_replaced(victim.as_ref(), newname);
+                    self.core
+                        .restore_replaced(victim.as_ref(), &new_parent_uid, newname);
                     reply.error(e);
                 }
             }
         };
         if rename_needs_queue(
-            self.core.is_online(),
+            self.core.sends_inline(),
             is_local_uid(&new_parent_uid),
             newparent != parent,
             newname != name,
@@ -2052,8 +2093,6 @@ impl ProtonFs {
             queue_it(reply);
             return;
         }
-        // Rename first if both halves change. Moving first makes the encrypted
-        // name requirements stale and repeatedly failed with InvalidRequirements.
         // A failure past this point has already trashed any node the rename was
         // replacing, so put it back rather than leaving the caller with neither
         // the source moved nor the destination intact.
@@ -2063,68 +2102,37 @@ impl ProtonFs {
             &old_parent_uid,
             &new_parent_uid,
         ) {
-            self.core.restore_replaced(victim.as_ref(), newname);
+            self.core
+                .restore_replaced(victim.as_ref(), &new_parent_uid, newname);
             reply.error(error);
             return;
         }
-        if newname != name
+        // A move that also renames is one request, so the name only has to be
-            && let Err(e) = self.core.rename_remote(&uid, newname)
+        // free in the destination, and the reply never stands for half of it.
-        {
+        let renamed = if newparent != parent {
+            let target = (newname != name).then_some(newname);
+            self.core.move_rename_remote(&uid, &new_parent_uid, target)
+        } else if newname != name {
+            self.core.rename_remote(&uid, newname)
+        } else {
+            Ok(())
+        };
+        if let Err(e) = renamed {
             if self.core.lost_link(&e, "rename") {
                 queue_it(reply);
                 return;
             }
             error!(%uid, error = %e, "rename failed");
-            self.core.restore_replaced(victim.as_ref(), newname);
+            self.core
+                .restore_replaced(victim.as_ref(), &new_parent_uid, newname);
             reply.error(Errno::EIO);
             return;
         }
-        if newparent != parent {
+        // Through the guard, so the database has both folders unlisted before
-            let mut attempts = 0u32;
+        // the reply. The next lookup rebuilds a folder still marked listed from
-            let moved = loop {
+        // the database, which did not have the move yet (docs/BUGS.md B135).
-                match self
-                    .core
-                    .block_on_bounded(self.core.client.move_node(&uid, &new_parent_uid))
-                {
-                    Ok(()) => break Ok(()),
-                    Err(e)
-                        if newname != name
-                            && api_code(&e) == Some(ResponseCode::InvalidRequirements)
-                            && attempts < 20 =>
-                    {
-                        attempts += 1;
-                        // Requirement propagation routinely takes longer than
-                        // three seconds. Keep a bounded ten-second window; a
-                        // successful POSIX reply must mean both remote halves
-                        // landed, not merely that the second half was queued.
-                        std::thread::sleep(Duration::from_millis(500));
-                    }
-                    Err(e) => break Err(e),
-                }
-            };
-            if let Err(e) = moved {
-                if self.core.lost_link(&e, "move") {
-                    queue_it(reply);
-                    return;
-                }
-                error!(%uid, attempts, error = %e, "move after rename failed");
-                // The rename half landed in the source directory.
-                let mut state = self.core.state();
-                let old_parent_uid = state
-                    .entries
-                    .get(&parent)
-                    .map(|entry| entry.uid.clone())
-                    .unwrap_or_else(|| uid.clone());
-                state.rename_in_place(ino, parent, &old_parent_uid, newname);
-                drop(state);
-                self.core.restore_replaced(victim.as_ref(), newname);
-                reply.error(Errno::EIO);
-                return;
-            }
-        }
         self.core
-            .state
+            .state()
-            .lock()
             .relocate(ino, parent, newparent, &new_parent_uid, newname);
         reply.ok();
     }
@@ -2150,7 +2158,7 @@ impl ProtonFs {
             reply.error(error);
             return;
         }
-        let (ino, uid) = match self.core.lookup_child(parent, name) {
+        let (ino, mut uid) = match self.core.lookup_child(parent, name) {
             Ok(x) => x,
             Err(e) => {
                 reply.error(e);
@@ -2166,7 +2174,7 @@ impl ProtonFs {
             .is_some_and(|e| e.open_count > 0);
         // A node the server has never heard of cannot be trashed there; deleting
         // it just means its queued creation is no longer wanted. This works
-        // offline, which the remote path below cannot (offline.md Phase 3b).
+        // offline, which the remote path below cannot.
         if is_local_uid(&uid) {
             let dropped = if open_now {
                 self.core.withdraw_queued_ops(&uid)
@@ -2178,19 +2186,30 @@ impl ProtonFs {
                 return;
             }
             self.core.state().forget_or_unlink(&uid);
-            debug!(%uid, name, "deleted a node that had not been created remotely yet");
+            // A create that landed before the ops were dropped left none: Drive
-            reply.ok();
+            // has the node, and the tree had not taken its uid yet. It is
-            return;
+            // trashed there like any other (docs/BUGS.md B173).
+            match self.core.landed_row_uid(ino) {
+                Some(real) => {
+                    debug!(local = %uid, %real, name, "create landed under a delete");
+                    uid = real;
+                }
+                None => {
+                    debug!(%uid, name, "deleted a node that had not been created remotely yet");
+                    reply.ok();
+                    return;
+                }
+            }
         }
         // Offline: queue it. Trashing is the one mutation a user expects to work
         // regardless — the file is gone from their point of view the moment the
-        // command returns (offline.md Phase 3b). The same when the network goes
+        // 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) {
             Ok(()) => reply.ok(),
             Err(e) => reply.error(e),
         };
-        if !self.core.is_online() {
+        if !self.core.sends_inline() {
             queue_it(reply);
             return;
         }
@@ -2200,7 +2219,7 @@ impl ProtonFs {
         }
         if let Err(e) = self
             .core
-            .block_on_bounded(self.core.client.trash_nodes(std::slice::from_ref(&uid)))
+            .block_on_bounded(self.core.drive.trash_nodes(std::slice::from_ref(&uid)))
             .and_then(batch::into_unit)
         {
             if self.core.lost_link(&e, "trash") {
@@ -2233,7 +2252,7 @@ impl ProtonFs {
         self.core.invalidate_trash();
         // Every other trash site records itself; this one did not, which made a
         // file found in the trash impossible to attribute after the fact — the
-        // activity log was the only record and it showed nothing (bugs.md B2).
+        // activity log was the only record and it showed nothing (`docs/BUGS.md` B2).
         self.core
             .log_activity(ActivityKind::Trash, name, "trashed from the mount", true);
         reply.ok();

crates/pdfs-fuse/src/link.rs

@@ -9,15 +9,16 @@
 //! queued path, and the probe thread here flips it back when Proton answers.
 
 use std::future::Future;
-use std::sync::atomic::Ordering;
+use std::sync::atomic::{AtomicBool, Ordering};
 use std::time::{Duration, Instant};
 
 use parking_lot::{Condvar, Mutex};
+use pdfs_core::error::session_revoked;
 use proton_drive_rs::proton_sdk::api::ResponseCode;
 use proton_drive_rs::proton_sdk::error::{ProtonApiError, ProtonError};
 use tracing::{debug, info, warn};
 
-use crate::{Core, ONLINE_PROBE_MAX, ONLINE_PROBE_MIN, ROOT_INO};
+use crate::{Core, ONLINE_PROBE_MAX, ONLINE_PROBE_MIN};
 
 /// How long a remote call a FUSE handler is waiting on may take before the link
 /// is treated as down.
@@ -54,6 +55,26 @@ pub(crate) struct Link {
     changed: Condvar,
     /// Folders listed from the DB alone while offline, to relist once back.
     pub(crate) stale_listings: Mutex<std::collections::HashSet<u64>>,
+    /// Proton refused the session itself ([`session_revoked`]). The mount is
+    /// offline then, but no probe brings it back: only a new login does, and
+    /// that restarts the daemon. Read by front-ends through `Response::Status`,
+    /// so they can ask the user to sign in again rather than say "offline".
+    pub(crate) session_expired: AtomicBool,
+    /// Proton refused the session, but only because another process rotated
+    /// it (`pdfs unlock`): the keyring holds the live tokens. The mount loop
+    /// ends the mount for the daemon to mount again from the keyring.
+    pub(crate) resume_stored: AtomicBool,
+}
+
+impl Link {
+    /// The link of a mount that comes up with Proton refusing its session, or
+    /// not.
+    pub(crate) fn starting(session_expired: bool) -> Self {
+        Self {
+            session_expired: AtomicBool::new(session_expired),
+            ..Default::default()
+        }
+    }
 }
 
 /// Whether a failed call failed because Proton could not be reached, rather
@@ -86,13 +107,32 @@ pub(crate) fn no_answer(after: Duration) -> ProtonError {
     })
 }
 
+/// The slowest upload rate an upload's deadline allows for, past the
+/// metadata budget it starts with. Far below any link that works, so only a
+/// transfer that has stopped moving runs into it.
+const SLOWEST_UPLOAD: u64 = 32 * 1024;
+
+/// 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)
+}
+
 /// Run a remote call, giving up after [`INTERACTIVE_CALL_TIMEOUT`].
 pub(crate) async fn bounded<T>(
     call: impl Future<Output = Result<T, ProtonError>>,
 ) -> Result<T, ProtonError> {
-    match tokio::time::timeout(INTERACTIVE_CALL_TIMEOUT, call).await {
+    bounded_by(INTERACTIVE_CALL_TIMEOUT, call).await
+}
+
+/// Run a remote call, giving up after `limit`.
+pub(crate) async fn bounded_by<T>(
+    limit: Duration,
+    call: impl Future<Output = Result<T, ProtonError>>,
+) -> Result<T, ProtonError> {
+    match tokio::time::timeout(limit, call).await {
         Ok(result) => result,
-        Err(_) => Err(no_answer(INTERACTIVE_CALL_TIMEOUT)),
+        Err(_) => Err(no_answer(limit)),
     }
 }
 
@@ -113,6 +153,15 @@ impl Core {
         self.online.load(Ordering::Relaxed)
     }
 
+    /// Whether a namespace change through the mount goes to Drive inside the
+    /// syscall. Only with [`AppConfig::local_first`] off, and only online;
+    /// otherwise it is queued and the drain sends it.
+    ///
+    /// [`AppConfig::local_first`]: pdfs_core::config::AppConfig::local_first
+    pub(crate) fn sends_inline(&self) -> bool {
+        !self.local_first && self.is_online()
+    }
+
     /// Run a remote call a caller is waiting on, giving up after
     /// [`INTERACTIVE_CALL_TIMEOUT`]. The timer is built inside the runtime: a
     /// FUSE worker has no reactor of its own.
@@ -123,10 +172,30 @@ impl Core {
         self.rt.block_on(bounded(call))
     }
 
+    /// Run a remote call, giving up after `limit`: an upload, whose budget
+    /// grows with its size ([`upload_deadline`]).
+    pub(crate) fn block_on_within<T>(
+        &self,
+        limit: Duration,
+        call: impl Future<Output = Result<T, ProtonError>>,
+    ) -> Result<T, ProtonError> {
+        self.rt.block_on(bounded_by(limit, call))
+    }
+
+    /// Whether Proton refused the session itself, so nothing reaches it until
+    /// the user signs in again.
+    pub(crate) fn session_expired(&self) -> bool {
+        self.link.session_expired.load(Ordering::Relaxed)
+    }
+
     /// Report a failed remote call. Returns whether it failed for want of a
-    /// network, in which case the mount is now offline and the caller should
+    /// network, or of a session, in which case the mount is now offline and the
-    /// take its queued path instead of failing.
+    /// caller should take its queued path instead of failing.
     pub(crate) fn lost_link(&self, e: &ProtonError, what: &str) -> bool {
+        if session_revoked(e) {
+            self.mark_session_expired(what, e);
+            return true;
+        }
         if !is_network_error(e) {
             return false;
         }
@@ -134,6 +203,29 @@ impl Core {
         true
     }
 
+    /// Flip the mount offline for good: Proton refused the session, and only a
+    /// new login brings it back. Changes stay queued for the daemon that login
+    /// starts. Only the first caller logs it.
+    ///
+    /// Unless the keyring holds a newer session than the refused one: then
+    /// the mount ends, for the daemon to mount again on that one.
+    pub(crate) fn mark_session_expired(&self, what: &str, error: &dyn std::fmt::Display) {
+        if self.link.resume_stored.load(Ordering::Relaxed) {
+            return self.mark_offline(what, error);
+        }
+        if pdfs_core::auth::stored_session_is_newer() {
+            info!(during = what, %error,
+                  "Proton refused a session another process has since refreshed; resuming it");
+            self.link.resume_stored.store(true, Ordering::Relaxed);
+            return self.mark_offline(what, error);
+        }
+        if !self.link.session_expired.swap(true, Ordering::Relaxed) {
+            warn!(during = what, %error,
+                  "Proton refused the session; run `pdfs login` to sign in again");
+        }
+        self.mark_offline(what, error);
+    }
+
     /// Flip the mount offline and wake the probe. Only the first caller of an
     /// outage logs it; the rest are the same outage.
     pub(crate) fn mark_offline(&self, what: &str, error: &dyn std::fmt::Display) {
@@ -210,7 +302,7 @@ impl Core {
     }
 
     /// Watch the link for the life of the mount: sleep while it is up, and
-    /// probe it back while it is down (offline.md Phase 1).
+    /// probe it back while it is down.
     ///
     /// A mount that started from the cache is down from the first moment; one
     /// that started online goes down when [`Core::mark_offline`] says so.
@@ -238,6 +330,9 @@ impl Core {
 
     /// Probe until Proton answers, then flip the mount online. Returns `false`
     /// if the daemon is stopping.
+    ///
+    /// A refused session is not probed: every probe would be refused the same
+    /// way, forever (issue #35). The thread waits for the stop instead.
     fn probe_until_online(&self) -> bool {
         let started = self.link.lost_at.lock().unwrap_or_else(Instant::now);
         let mut delay = if started.elapsed() < YOUNG_OUTAGE {
@@ -249,8 +344,12 @@ impl Core {
             if !self.shutdown.sleep(delay) {
                 return false;
             }
+            if self.session_expired() {
+                delay = ONLINE_PROBE_MAX;
+                continue;
+            }
             let probe = self.rt.block_on(async {
-                match tokio::time::timeout(PROBE_TIMEOUT, self.client.get_my_files_folder()).await {
+                match tokio::time::timeout(PROBE_TIMEOUT, self.drive.get_my_files_folder()).await {
                     Ok(result) => result,
                     Err(_) => Err(no_answer(PROBE_TIMEOUT)),
                 }
@@ -258,8 +357,9 @@ impl Core {
             match probe {
                 Ok(root) => {
                     {
+                        let root_ino = self.root_ino();
                         let mut st = self.state();
-                        if let Some(e) = st.entries.get_mut(&ROOT_INO) {
+                        if let Some(e) = st.entries.get_mut(&root_ino) {
                             e.node = root.clone();
                         }
                     }
@@ -269,6 +369,7 @@ impl Core {
                     self.mark_online();
                     return true;
                 }
+                Err(e) if session_revoked(&e) => self.mark_session_expired("online probe", &e),
                 Err(e) => {
                     debug!(error = %e, ?delay, "online probe failed; still offline");
                     delay = next_probe_delay(delay, started.elapsed());
@@ -300,6 +401,26 @@ mod tests {
         assert!(!is_network_error(&ProtonError::invalid_operation("bug")));
     }
 
+    #[test]
+    fn an_upload_gets_longer_the_bigger_it_is() {
+        assert_eq!(upload_deadline(0), INTERACTIVE_CALL_TIMEOUT);
+        assert_eq!(
+            upload_deadline(1 << 30),
+            INTERACTIVE_CALL_TIMEOUT + Duration::from_secs(32_768)
+        );
+    }
+
+    #[test]
+    fn a_call_past_its_deadline_reads_as_a_lost_link() {
+        let rt = tokio::runtime::Builder::new_current_thread()
+            .enable_time()
+            .build()
+            .unwrap();
+        let limit = Duration::from_millis(20);
+        let result: Result<(), _> = rt.block_on(bounded_by(limit, std::future::pending()));
+        assert!(result.is_err_and(|e| is_network_error(&e)));
+    }
+
     #[test]
     fn a_young_outage_is_probed_often_and_an_old_one_rarely() {
         let young = Duration::from_secs(60);

crates/pdfs-fuse/src/mount.rs

@@ -12,6 +12,10 @@ pub enum MountOutcome {
     /// The kernel mount ended on its own (e.g. an external `fusermount -u`).
     /// The caller may want to remount.
     Unmounted,
+    /// Proton refused the session, and the keyring holds a newer one: another
+    /// process (`pdfs unlock`) refreshed it, or a new login replaced it. We
+    /// unmounted ourselves; the caller should mount again, which resumes it.
+    ResumeStored,
 }
 
 /// Whether `path` is a mountpoint whose FUSE connection is dead — the state a
@@ -193,7 +197,7 @@ pub(super) fn clear_stale_mount(mountpoint: &Path) {
 }
 
 /// `sync_state` key holding the uid of the My Files root, so a later run can
-/// recover it from `nodes` without the API (offline.md Phase 1).
+/// recover it from `nodes` without the API.
 const ROOT_UID_KEY: &str = "root_uid";
 
 /// The My Files root, and whether we got it from the API (`true`) or from the
@@ -207,33 +211,63 @@ const ROOT_UID_KEY: &str = "root_uid";
 /// means an empty tree, and mounting that would show the user an empty Drive
 /// rather than an honest error.
 fn fetch_or_recall_root(
-    client: &ProtonDriveClient,
+    drive: &dyn DriveApi,
     rt: &tokio::runtime::Handle,
     db: &Db,
-) -> std::io::Result<(Node, bool)> {
+) -> std::io::Result<(Node, Start)> {
-    let err = match rt.block_on(client.get_my_files_folder()) {
+    let err = match rt.block_on(drive.get_my_files_folder()) {
         Ok(root) => {
             if let Err(e) = db.set_state_str(ROOT_UID_KEY, &root.uid.to_string()) {
                 warn!(error = %e, "persist root uid failed");
             }
-            return Ok((root, true));
+            return Ok((root, Start::Online));
         }
         Err(e) => e,
     };
+    // Still mounted from the cache, so cached files stay readable and changes
+    // queue for the daemon the next login starts.
+    let start = if pdfs_core::error::session_revoked(&err) {
+        Start::SessionExpired
+    } else {
+        Start::Offline
+    };
+    if start == Start::SessionExpired && pdfs_core::auth::stored_session_is_newer() {
+        return Err(std::io::Error::other(format!(
+            "Proton refused a session another process has since refreshed ({err}); resuming it"
+        )));
+    }
     let cached = db
         .state_str(ROOT_UID_KEY)
         .ok()
         .flatten()
         .and_then(|uid| db.node_by_uid(&uid).ok().flatten());
     match cached {
+        Some(root) if start == Start::SessionExpired => {
+            warn!(error = %err,
+                  "Proton refused the session; mounting from cache until `pdfs login`");
+            Ok((root, start))
+        }
         Some(root) => {
             warn!(error = %err, "fetch My Files root failed; mounting from cache (offline)");
-            Ok((root, false))
+            Ok((root, start))
         }
+        None if start == Start::SessionExpired => Err(std::io::Error::other(format!(
+            "Proton refused the session ({err}); run `pdfs login`"
+        ))),
         None => Err(std::io::Error::other(format!("fetch My Files root: {err}"))),
     }
 }
 
+/// How a mount comes up, from what fetching its root said.
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum Start {
+    Online,
+    /// Proton could not be reached: serve the cache and probe for the link.
+    Offline,
+    /// Proton refused the session: serve the cache until a new login.
+    SessionExpired,
+}
+
 /// Per-mount settings resolved from [`pdfs_core::config::AppConfig`] by the
 /// caller, so `mount` itself never reads config or the environment.
 pub struct MountOptions {
@@ -244,6 +278,9 @@ pub struct MountOptions {
     /// Upload and download caps in bytes per second (`0` = no cap).
     pub upload_limit: u64,
     pub download_limit: u64,
+    /// Namespace changes through the mount are queued, not sent in the
+    /// syscall. See [`pdfs_core::config::AppConfig::local_first`].
+    pub local_first: bool,
 }
 
 /// Spawn one FUSE session rooted at an arbitrary remote node.
@@ -276,13 +313,14 @@ pub(super) fn spawn_session(
     info!(mountpoint = %mountpoint.display(), "mounting Proton Drive location");
     let fs = ProtonFs::new(core.clone(), root);
     if core.primary {
-        // Only My Files rehydrates the daemon-wide node cache. A secondary
+        // Only My Files rehydrates the daemon-wide node cache, once. A
-        // inode space is rooted at one device subtree and must not import every
+        // secondary mount shares the tree it fills.
-        // unrelated persisted node.
         core.hydrate();
     }
     let session = Session::new(fs, mountpoint, &config)?.spawn()?;
-    let _ = core.notifier.set(session.notifier());
+    let _ = core
+        .notifier
+        .set(KernelChannel::new(session.notifier(), core.root_ino()));
     core.session_live.store(true, Ordering::Release);
     Ok(session)
 }
@@ -339,17 +377,58 @@ pub fn mount(
     control_socket: &Path,
     db: Arc<Db>,
     options: MountOptions,
+) -> std::io::Result<MountOutcome> {
+    let drive = Arc::new(client.clone());
+    mount_with(
+        client,
+        drive,
+        rt,
+        mountpoint,
+        cache,
+        control_socket,
+        db,
+        options,
+        Host::Daemon,
+    )
+}
+
+/// What a mount runs in.
+pub(crate) enum Host {
+    /// The daemon: stopped by SIGTERM or SIGINT, and indexing the user's home
+    /// for the launcher prompt.
+    Daemon,
+    /// One of several simulated daemons in a test process (`sim`): stopped by
+    /// a message on this channel, and with no home to index.
+    #[cfg(test)]
+    Simulation(std::sync::mpsc::Receiver<()>),
+}
+
+/// [`mount`], reaching Drive through `drive` and hosted by `host`; `client`
+/// serves only what [`DriveApi`] does not cover.
+#[allow(clippy::too_many_arguments)]
+pub(crate) fn mount_with(
+    client: ProtonDriveClient,
+    drive: Arc<dyn DriveApi>,
+    rt: tokio::runtime::Handle,
+    mountpoint: &Path,
+    cache: ContentCache,
+    control_socket: &Path,
+    db: Arc<Db>,
+    options: MountOptions,
+    host: Host,
 ) -> std::io::Result<MountOutcome> {
     let MountOptions {
         username,
         sweep_mode,
         upload_limit,
         download_limit,
+        local_first,
     } = options;
     // 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();
-    let (root, online) = fetch_or_recall_root(&client, &rt, &db)?;
+    let (root, start) = fetch_or_recall_root(drive.as_ref(), &rt, &db)?;
+    let online = start == Start::Online;
     let scope = root.tree_event_scope_id();
     db.mount_upsert_my_files(&mountpoint.to_string_lossy(), &root.uid.to_string(), None)
         .map_err(|error| std::io::Error::other(format!("project My Files mount: {error}")))?;
@@ -357,19 +436,21 @@ pub fn mount(
         .all_share_access()
         .map_err(|error| std::io::Error::other(format!("load shared access: {error}")))?;
 
-    // The folder-sync engine (devices.md Phase 2) runs on its own thread and is
+    // The folder-sync engine runs on its own thread and is
     // nudged over this channel; the sender lives in Core so control-socket
     // handlers can trigger reconciles.
     let (sync_tx, sync_rx) = std::sync::mpsc::channel::<sync::SyncMsg>();
 
     let paused_until = pause::load_paused_until(&db);
     let core = Core {
-        client: client.clone(),
+        drive,
+        client,
         rt: rt.clone(),
         maintenance: Arc::new(Mutex::new(Default::default())),
         primary_root_uid: root.uid.clone(),
         primary: true,
-        state: Arc::new(Mutex::new(State::new(db.clone(), share_access, 2))),
+        state: Arc::new(Mutex::new(State::new(db.clone(), share_access))),
+        root: Arc::new(OnceLock::new()),
         cache: Arc::new(cache),
         readers: Arc::new(Mutex::new(HashMap::new())),
         block_ring: Arc::new(Mutex::new(BlockRing::default())),
@@ -383,14 +464,19 @@ pub fn mount(
         shared_generation: Arc::new(AtomicU64::new(0)),
         shared_refresh_deadlines: Arc::new(Mutex::new(SharedRefreshDeadlines::default())),
         online: Arc::new(AtomicBool::new(online)),
-        link: Arc::new(Default::default()),
+        link: Arc::new(link::Link::starting(start == Start::SessionExpired)),
         sync_paused_until: Arc::new(AtomicI64::new(paused_until)),
         pending: Arc::new(Mutex::new(HashMap::new())),
         hidden: Arc::new(Mutex::new(HashSet::new())),
+        creating: Arc::new(Mutex::new(HashMap::new())),
+        sealed_unread: Arc::new(Mutex::new(HashMap::new())),
+        landed: Arc::new(Mutex::new(HashMap::new())),
+        unadopted: Arc::new(Mutex::new(HashMap::new())),
         drain_wake: Arc::new((Mutex::new(false), Condvar::new())),
         shutdown: Arc::new(crate::shutdown::Shutdown::default()),
         upload_times: Arc::new(Mutex::new(HashMap::new())),
         upload_cancel: Arc::new(Mutex::new(HashMap::new())),
+        landing_uploads: Arc::new(AtomicU64::new(0)),
         timeline_refreshing: Arc::new(AtomicBool::new(false)),
         timeline_progress: Arc::new(Mutex::new(None)),
         similar_hashing: Arc::new(AtomicBool::new(false)),
@@ -399,7 +485,7 @@ pub fn mount(
         trash_progress: Arc::new(tokio::sync::Notify::new()),
         conflict_notified: Arc::new(Mutex::new(HashSet::new())),
         sweep_mode,
-        own_sealed_revs: Arc::new(Mutex::new(HashMap::new())),
+        local_first,
         self_changes: Arc::new(Mutex::new(HashMap::new())),
         thumb_gen: Arc::new(Mutex::new(HashSet::new())),
         thumb_gen_budget: Arc::new(tokio::sync::Semaphore::new(
@@ -424,10 +510,11 @@ pub fn mount(
         sync_tx,
         mounts: Arc::new(Mutex::new(SecondaryMountRegistry::default())),
         sync_locks: Arc::new(Mutex::new(HashMap::new())),
+        sync_unscanned: Arc::new(Mutex::new(HashMap::new())),
         states: Arc::new(StateRegistry::default()),
     };
     // Before anything can queue work against it: the drain thread below reaches
-    // every mount's inode space through this registry, not through `core.state`.
+    // every mount's session through this registry.
     core.register_state(mountpoint);
     core.transfers.set_limits(upload_limit, download_limit);
 
@@ -450,7 +537,7 @@ pub fn mount(
     // Every long-lived thread started from here on is kept in `workers` and
     // joined at the end of this function. Leaving them running turned an
     // in-process remount into a second generation of drain workers, sync engines
-    // and sweeps all operating on a mount that no longer exists (bugs.md B44).
+    // 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();
@@ -500,7 +587,7 @@ pub fn mount(
 
     // Keep the launcher prompt's "This computer" index fresh. Its own thread:
     // the walk is I/O-heavy and must never sit in front of a FUSE callback.
-    {
+    if matches!(host, Host::Daemon) {
         let db = core.db.clone();
         let indexing = core.indexing.clone();
         let transfers = core.transfers.clone();
@@ -624,11 +711,13 @@ pub fn mount(
             }
         }
     };
-    rt.spawn(run_event_sync(client, scope, core.clone()));
+    rt.spawn(run_event_sync(core.drive.clone(), scope, core.clone()));
     // The photos volume has its own event stream; without it the gallery only
     // learns about a phone-side deletion when the timeline goes stale.
     rt.spawn(run_photos_event_sync(core.clone()));
-    if online {
+    // Not in a simulation: `client` there reaches no API, and the thread, still
+    // waiting on it after the stop, held the database a test opens next.
+    if online && matches!(host, Host::Daemon) {
         let repair_core = core.clone();
         let root_uid = core.primary_root_uid.clone();
         if let Err(error) = std::thread::Builder::new()
@@ -643,6 +732,82 @@ pub fn mount(
     // are delivered onto the async runtime; bridge them onto a sync channel so
     // the loop below can react without blocking a worker thread. A bounded
     // channel of 1 is enough — we only need to know that *a* stop arrived.
+    let sig_rx = match host {
+        Host::Daemon => signal_stop(&rt),
+        #[cfg(test)]
+        Host::Simulation(rx) => rx,
+    };
+
+    // Wait for whichever happens first: a stop signal (→ we unmount ourselves
+    // via the lazy MNT_DETACH path, clean even mid-download), or the kernel
+    // mount ending on its own (→ the session thread finishes). Poll instead of
+    // blocking on `join` so we can also notice the signal.
+    let outcome = loop {
+        match sig_rx.recv_timeout(Duration::from_millis(500)) {
+            Ok(()) => {
+                info!("stop requested; unmounting");
+                core.mounts.lock().close();
+                if let Err(e) = teardown_session(&core.session_live, || {
+                    umount_session_unblocked(bg, main_conn)
+                }) {
+                    warn!(error = %e, "umount_and_join failed");
+                }
+                break MountOutcome::Shutdown;
+            }
+            Err(std::sync::mpsc::RecvTimeoutError::Timeout)
+                if core.link.resume_stored.load(Ordering::Relaxed) =>
+            {
+                info!("unmounting to resume the stored session");
+                core.mounts.lock().close();
+                if let Err(e) = teardown_session(&core.session_live, || {
+                    umount_session_unblocked(bg, main_conn)
+                }) {
+                    warn!(error = %e, "umount_and_join failed");
+                }
+                break MountOutcome::ResumeStored;
+            }
+            Err(std::sync::mpsc::RecvTimeoutError::Timeout) => {
+                if bg.guard.is_finished() {
+                    info!("mount ended externally");
+                    core.mounts.lock().close();
+                    if let Err(e) = teardown_session(&core.session_live, || bg.join()) {
+                        warn!(error = %e, "session join failed");
+                    }
+                    break MountOutcome::Unmounted;
+                }
+            }
+            Err(std::sync::mpsc::RecvTimeoutError::Disconnected) => {
+                // Signal task gone (failed to install); fall back to join.
+                core.mounts.lock().close();
+                let _ = teardown_session(&core.session_live, || bg.join());
+                break MountOutcome::Unmounted;
+            }
+        }
+    };
+
+    // Unmount every on-demand sync folder too, or the kernel mounts linger as
+    // stale and the next start fails with EBUSY.
+    if let Some(worker) = restore_worker
+        && worker.join().is_err()
+    {
+        warn!("on-demand restore worker panicked");
+    }
+    let secondaries = core.mounts.lock().close_and_drain();
+    for (id, mount) in secondaries {
+        if let Err(e) = mount.teardown() {
+            warn!(id, error = %e, "unmount on-demand folder failed");
+        }
+    }
+    core.queue_unreleased_writes();
+
+    // Last, because the workers may legitimately be finishing an upload, and
+    // nothing they can still do is harmful once the mounts are down.
+    stop_workers(&core, control_socket, workers);
+    Ok(outcome)
+}
+
+/// A channel that receives once SIGTERM or SIGINT arrives.
+fn signal_stop(rt: &tokio::runtime::Handle) -> std::sync::mpsc::Receiver<()> {
     let (sig_tx, sig_rx) = std::sync::mpsc::sync_channel::<()>(1);
     rt.spawn(async move {
         let mut sigterm =
@@ -667,65 +832,13 @@ pub fn mount(
         }
         let _ = sig_tx.try_send(());
     });
-
+    sig_rx
-    // Wait for whichever happens first: a stop signal (→ we unmount ourselves
-    // via the lazy MNT_DETACH path, clean even mid-download), or the kernel
-    // mount ending on its own (→ the session thread finishes). Poll instead of
-    // blocking on `join` so we can also notice the signal.
-    let outcome = loop {
-        match sig_rx.recv_timeout(Duration::from_millis(500)) {
-            Ok(()) => {
-                info!("stop requested; unmounting");
-                core.mounts.lock().close();
-                if let Err(e) = teardown_session(&core.session_live, || {
-                    umount_session_unblocked(bg, main_conn)
-                }) {
-                    warn!(error = %e, "umount_and_join failed");
-                }
-                break MountOutcome::Shutdown;
-            }
-            Err(std::sync::mpsc::RecvTimeoutError::Timeout) => {
-                if bg.guard.is_finished() {
-                    info!("mount ended externally");
-                    core.mounts.lock().close();
-                    if let Err(e) = teardown_session(&core.session_live, || bg.join()) {
-                        warn!(error = %e, "session join failed");
-                    }
-                    break MountOutcome::Unmounted;
-                }
-            }
-            Err(std::sync::mpsc::RecvTimeoutError::Disconnected) => {
-                // Signal task gone (failed to install); fall back to join.
-                core.mounts.lock().close();
-                let _ = teardown_session(&core.session_live, || bg.join());
-                break MountOutcome::Unmounted;
-            }
-        }
-    };
-
-    // Unmount every on-demand sync folder too, or the kernel mounts linger as
-    // stale and the next start fails with EBUSY (devices.md Phase 3).
-    if let Some(worker) = restore_worker
-        && worker.join().is_err()
-    {
-        warn!("on-demand restore worker panicked");
-    }
-    let secondaries = core.mounts.lock().close_and_drain();
-    for (id, mount) in secondaries {
-        if let Err(e) = mount.teardown() {
-            warn!(id, error = %e, "unmount on-demand folder failed");
-        }
-    }
-
-    // Last, because the workers may legitimately be finishing an upload, and
-    // nothing they can still do is harmful once the mounts are down.
-    stop_workers(&core, control_socket, workers);
-    Ok(outcome)
 }
 
-/// How long teardown waits for the FUSE worker pool before proceeding without
+/// How long teardown waits for the background workers and then the FUSE worker
-/// it. Long enough for an in-flight block to finish, short enough that
+/// pool before proceeding without them. Long enough for an in-flight block to
-/// `systemctl --user stop` still returns inside `TimeoutStopSec`.
+/// finish, short enough that `systemctl --user stop` still returns inside
+/// `TimeoutStopSec`.
 const WORKER_JOIN_DEADLINE: Duration = Duration::from_secs(10);
 
 /// Signal every background loop, wake the ones that are blocked, and join them.
@@ -733,14 +846,15 @@ const WORKER_JOIN_DEADLINE: Duration = Duration::from_secs(10);
 /// The mount used to return with its drain workers, sync engine, sweep, online
 /// probe, indexer and control listener all still running on `Core` clones. The
 /// process usually exited straight afterwards and hid it; an in-process remount
-/// did not, and started a second full set on top of the first (bugs.md B44).
+/// did not, and started a second full set on top of the first (`docs/BUGS.md` B44).
 ///
 /// Two of the waits need waking rather than merely flagging: the drain workers
 /// block on their own condvar (`wake_drain`), and the control listener blocks
 /// inside `accept`, which only returns when a connection arrives — so it gets
 /// one, from us, after the flag is already set. A join that takes a while is
 /// expected and correct: a worker part-way through an upload finishes it rather
-/// than abandoning the user's bytes mid-flight.
+/// than abandoning the user's bytes mid-flight. Up to [`WORKER_JOIN_DEADLINE`]:
+/// past it, systemd kills the daemon anyway, and a queued op is sent again.
 fn stop_workers(core: &Core, control_socket: &Path, workers: Vec<std::thread::JoinHandle<()>>) {
     // 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.
@@ -754,25 +868,71 @@ fn stop_workers(core: &Core, control_socket: &Path, workers: Vec<std::thread::Jo
     // unlink cannot put it back to sleep.
     let _ = std::os::unix::net::UnixStream::connect(control_socket);
     let _ = std::fs::remove_file(control_socket);
-    for worker in workers {
+    let deadline = Instant::now() + WORKER_JOIN_DEADLINE;
-        if worker.join().is_err() {
+    let running = join_until(workers, deadline);
-            warn!("a background worker panicked before shutdown");
+    if !running.is_empty() {
-        }
+        warn!(
+            running = running.join(","),
+            "background workers did not finish in time; shutting down around them"
+        );
     }
     // The FUSE worker pool last, and *before* the caller drops the tokio
     // runtime: a worker still inside a job when the runtime goes away panics on
     // its next timer with "A Tokio 1.x context was found, but it is being
     // shutdown" (seen 2026-09-18 09:58:35). Bounded, so a worker wedged on the
     // network cannot hold the stop the user asked for.
-    core.workers.stop_and_join(WORKER_JOIN_DEADLINE);
+    core.workers
+        .stop_and_join(deadline.saturating_duration_since(Instant::now()));
     debug!("background workers stopped");
 }
 
+/// Join `workers` until `deadline`, and name the ones still running then.
+///
+/// A stop used to wait for each one however long it took. The sync engine's
+/// mirror pass waits on Drive with no deadline, and a stop that waited for it
+/// was killed by systemd (`docs/BUGS.md` B165).
+fn join_until(workers: Vec<std::thread::JoinHandle<()>>, deadline: Instant) -> Vec<String> {
+    let mut running = Vec::new();
+    for worker in workers {
+        while !worker.is_finished() && Instant::now() < deadline {
+            std::thread::sleep(Duration::from_millis(10));
+        }
+        if !worker.is_finished() {
+            running.push(worker.thread().name().unwrap_or("unnamed").to_string());
+        } else if worker.join().is_err() {
+            warn!("a background worker panicked before shutdown");
+        }
+    }
+    running
+}
+
 #[cfg(test)]
 mod tests {
     use std::sync::atomic::{AtomicBool, Ordering};
+    use std::time::{Duration, Instant};
 
-    use super::{SecondaryInsertRejection, SecondaryMountRegistry, teardown_session};
+    use super::{SecondaryInsertRejection, SecondaryMountRegistry, join_until, teardown_session};
+
+    #[test]
+    fn a_stop_names_the_workers_still_running_at_its_deadline() {
+        let (release, wait) = std::sync::mpsc::channel::<()>();
+        let done = std::thread::Builder::new()
+            .name("done".into())
+            .spawn(|| {})
+            .unwrap();
+        let stuck = std::thread::Builder::new()
+            .name("stuck".into())
+            .spawn(move || {
+                let _ = wait.recv();
+            })
+            .unwrap();
+        let running = join_until(
+            vec![done, stuck],
+            Instant::now() + Duration::from_millis(100),
+        );
+        assert_eq!(running, ["stuck"]);
+        drop(release);
+    }
 
     #[test]
     fn session_is_unroutable_before_teardown_starts() {

crates/pdfs-fuse/src/photos.rs

@@ -1038,7 +1038,7 @@ impl Core {
         }
         let outcomes = self
             .rt
-            .block_on(self.client.trash_nodes(uids))
+            .block_on(self.drive.trash_nodes(uids))
             .map_err(|e| CoreError::from_api(&e, "trash"))?;
         let (trashed, failed) = pdfs_core::batch::split(outcomes);
 

crates/pdfs-fuse/src/profile.rs

@@ -1,5 +1,5 @@
 //! Reading and writing this machine's `profile.json` in its device root, and
-//! the restore that rebuilds a machine from one (features.md 5.2 and 5.3).
+//! the restore that rebuilds a machine from one.
 //!
 //! The document itself is defined in [`pdfs_core::profile`]; this is the half
 //! that talks to Drive. Saving is best-effort and never blocks a user action:
@@ -101,7 +101,7 @@ impl Core {
         match existing {
             Some(uid) => self
                 .rt
-                .block_on(self.client.upload_new_revision_from(
+                .block_on(self.drive.upload_new_revision_from(
                     &uid,
                     Cursor::new(bytes),
                     len,
@@ -112,7 +112,7 @@ impl Core {
                 .map_err(|e| CoreError::from_api(&e, "upload profile revision"))?,
             None => {
                 self.rt
-                    .block_on(self.client.upload_file_replacing_draft_from(
+                    .block_on(self.drive.upload_file_replacing_draft_from(
                         &dir_uid,
                         PROFILE_FILE_NAME,
                         "application/json",
@@ -182,14 +182,14 @@ impl Core {
     ) -> CoreResult<Option<NodeUid>> {
         let uids = self
             .rt
-            .block_on(self.client.enumerate_folder_children_node_uids(parent_uid))
+            .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(None);
         }
         let nodes = self
             .rt
-            .block_on(self.client.enumerate_nodes(&uids))
+            .block_on(self.drive.enumerate_nodes(&uids))
             .map_err(|e| CoreError::from_api(&e, "resolve device root children"))?;
         Ok(nodes
             .into_iter()
@@ -210,7 +210,7 @@ impl Core {
         let uid = self
             .rt
             .block_on(
-                self.client
+                self.drive
                     .create_folder(root_uid, PROFILE_DIR_NAME, Some(now_secs())),
             )
             .map_err(|e| CoreError::from_api(&e, "create profile folder"))?;
@@ -241,12 +241,12 @@ impl Core {
         };
         let mut buf: Vec<u8> = Vec::new();
         self.rt
-            .block_on(self.client.download_file_to(&uid, &mut buf))
+            .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)
     }
 
-    // ---- restore (features.md 5.2) ----------------------------------------
+    // ---- restore ----------------------------------------
 
     /// The folders under a device that could be synced here, each carrying a
     /// proposed local path. `device` names another registered device by uid;
@@ -277,13 +277,13 @@ impl Core {
 
         let uids = self
             .rt
-            .block_on(self.client.enumerate_folder_children_node_uids(&root_uid))
+            .block_on(self.drive.enumerate_folder_children_node_uids(&root_uid))
             .map_err(|e| CoreError::from_api(&e, "list device root"))?;
         let nodes = if uids.is_empty() {
             Vec::new()
         } else {
             self.rt
-                .block_on(self.client.enumerate_nodes(&uids))
+                .block_on(self.drive.enumerate_nodes(&uids))
                 .map_err(|e| CoreError::from_api(&e, "resolve device root children"))?
         };
 

crates/pdfs-fuse/src/queue.rs

@@ -1,12 +1,16 @@
 //! The user's view of the pending-op queue: what has not reached the remote
 //! yet, why, and a way to stop waiting out a backoff.
 //!
-//! Read-only apart from "retry now", which only moves a row's next-attempt time.
+//! Read-only apart from "retry now", which only moves a row's next-attempt time,
-//! Nothing here drops a queued op: its staged blob is the only copy of the
+//! "export", which copies a staged blob out, and "discard". Only a discard the
-//! user's write (see `docs/RECOVERY.md`).
+//! user asks for drops a queued op: its staged blob is the only copy of the
+//! user's write (see `docs/RECOVERY.md`), so it is the user's call, made after
+//! an export or for a change with no content.
 
 use super::*;
-use pdfs_core::control::PendingOpInfo;
+use std::io::Write;
+
+use pdfs_core::control::{PendingOpInfo, SyncIssue};
 use pdfs_core::db::{FAILING_ATTEMPTS, PARK_UNTIL};
 
 impl Core {
@@ -16,10 +20,15 @@ impl Core {
             .db
             .pending_ops()
             .map_err(|e| CoreError::internal(format!("listing the queue: {e}")))?;
+        let issues = self
+            .db
+            .op_issues()
+            .map_err(|e| CoreError::internal(format!("listing sync issues: {e}")))?;
         Ok(ops
             .into_iter()
             .map(|op| {
                 let parked = op.next_attempt_at >= PARK_UNTIL;
+                let exportable = exportable(&op).is_some();
                 let path = self
                     .db
                     .node_path(&op.uid)
@@ -37,7 +46,9 @@ impl Core {
                     queued_at: op.created_at / 1000,
                     next_attempt_at: (!parked).then_some(op.next_attempt_at / 1000),
                     parked,
-                    failing: op.attempts >= FAILING_ATTEMPTS,
+                    failing: op.attempts >= FAILING_ATTEMPTS || issues.contains_key(&op.id),
+                    issue: issues.get(&op.id).map(|issue| SyncIssue::parse(issue)),
+                    exportable,
                 }
             })
             .collect())
@@ -57,4 +68,235 @@ impl Core {
         }
         Ok(moved)
     }
+
+    /// Copy the content of queued op `id` to `dest`, which must not exist yet.
+    /// The op stays queued. Returns the bytes written.
+    pub(crate) fn export_pending_op(&self, id: i64, dest: &Path) -> CoreResult<u64> {
+        if !dest.is_absolute() {
+            return Err(CoreError::invalid(format!(
+                "destination must be an absolute path: {}",
+                dest.display()
+            )));
+        }
+        let ops = self
+            .db
+            .pending_ops()
+            .map_err(|e| CoreError::internal(format!("listing the queue: {e}")))?;
+        let op = ops
+            .iter()
+            .find(|op| op.id == id)
+            .ok_or_else(|| CoreError::not_found(format!("no queued change {id}")))?;
+        let blob = exportable(op).ok_or_else(|| {
+            CoreError::invalid(format!("queued change {id} carries no file content"))
+        })?;
+        let written = copy_to_new_file(blob, dest)?;
+        info!(id, dest = %dest.display(), written, "exported a queued change's content");
+        Ok(written)
+    }
+
+    /// Drop queued op `id` and undo the local change it stood for. Returns the
+    /// node's path.
+    ///
+    /// A node only made here goes, as if it had been deleted before it was
+    /// sent. A node Drive has goes back to what Drive has: every change queued
+    /// on it goes, since each was made on top of the one before. What is queued
+    /// below it stays.
+    pub(crate) fn discard_pending_op(&self, id: i64) -> CoreResult<String> {
+        let ops = self
+            .db
+            .pending_ops()
+            .map_err(|e| CoreError::internal(format!("listing the queue: {e}")))?;
+        let op = ops
+            .into_iter()
+            .find(|op| op.id == id)
+            .ok_or_else(|| CoreError::not_found(format!("no queued change {id}")))?;
+        let uid = parse_node_uid(&op.uid)
+            .ok_or_else(|| CoreError::internal(format!("queued change {id} names {}", op.uid)))?;
+        let path = self
+            .db
+            .node_path(&op.uid)
+            .ok()
+            .flatten()
+            .filter(|path| !path.is_empty())
+            .or(op.name)
+            .unwrap_or_else(|| op.uid.clone());
+        if self.is_open_anywhere(&uid) {
+            return Err(CoreError::conflict(format!(
+                "{path} is open; close it first"
+            )));
+        }
+        if is_local_uid(&uid) {
+            self.discard_local_node(&uid, &path)?;
+        } else {
+            self.discard_remote_change(&uid, &path)?;
+        }
+        info!(id, %uid, path, "discarded a queued change");
+        Ok(path)
+    }
+
+    /// Forget a node made here, and the ops that would have sent it.
+    fn discard_local_node(&self, uid: &NodeUid, path: &str) -> CoreResult<()> {
+        // Its children's ops go with its own, and their content with them.
+        if self
+            .db
+            .has_children(uid)
+            .map_err(|e| CoreError::internal(format!("listing {path}: {e}")))?
+        {
+            return Err(CoreError::conflict(format!(
+                "{path} is not empty; discard what is in it first"
+            )));
+        }
+        self.discard_queued_ops(uid)
+            .map_err(|_| CoreError::internal(format!("dropping the changes to {path}")))?;
+        self.for_each_mount(|st, notify| {
+            background::forget_and_notify(st, notify, uid);
+        });
+        self.cache.evict(uid);
+        self.evict_reader(uid);
+        Ok(())
+    }
+
+    /// Put a node Drive has back as Drive has it.
+    fn discard_remote_change(&self, uid: &NodeUid, path: &str) -> CoreResult<()> {
+        // Asked first: the change is only dropped once what replaces it is known.
+        let node = self
+            .fetch_node_remote(uid)
+            .map_err(|e| CoreError::from_api(&e, "reading the node from Drive"))?
+            .filter(|node| !node.trashed);
+        self.cancel_upload(uid);
+        let blobs = self
+            .db
+            .discard_ops_on_node(&uid.to_string())
+            .map_err(|e| CoreError::internal(format!("dropping the changes to {path}: {e}")))?
+            .ok_or_else(|| {
+                CoreError::conflict(format!("{path} is being sent right now; try again"))
+            })?;
+        self.release_dropped_ops(uid, blobs);
+        self.hidden.lock().remove(uid);
+        match node {
+            Some(node) => self.for_each_mount(|st, notify| {
+                put_back(st, notify, node);
+            }),
+            None => self.for_each_mount(|st, notify| {
+                background::forget_and_notify(st, notify, uid);
+            }),
+        }
+        self.cache.evict(uid);
+        self.evict_reader(uid);
+        Ok(())
+    }
+}
+
+/// Show `node` as Drive has it, where Drive has it, under the inode it has.
+fn put_back(st: &mut State, notify: &mut NotifyBatch, node: Node) {
+    let parent = node.parent_uid.as_ref().and_then(|parent| {
+        st.by_uid
+            .get(parent)
+            .copied()
+            .map(|ino| (ino, parent.clone()))
+    });
+    let here = st.by_uid.get(&node.uid).and_then(|ino| {
+        st.entries
+            .get(ino)
+            .map(|entry| (*ino, entry.parent, entry.node.name.clone()))
+    });
+    match (here, parent) {
+        (Some((ino, from, name)), Some((to, to_uid))) => {
+            st.relocate(ino, from, to, &to_uid, &node.name);
+            st.write_through(node.clone());
+            st.intern_mem(to, node);
+            notify.inval_entry(from, name);
+            notify.inval_inode(ino);
+        }
+        (here, parent) => {
+            if let Some((_, from, name)) = here {
+                st.forget_mem(&node.uid);
+                st.invalidate_listing(from);
+                notify.inval_entry(from, name);
+            }
+            if let Some((to, _)) = parent {
+                st.invalidate_listing(to);
+                notify.inval_entry(to, node.name.clone());
+            }
+            st.write_through(node);
+        }
+    }
+}
+
+/// Copy `blob` to `dest`, which must not exist: never replace something the
+/// user already has.
+fn copy_to_new_file(blob: &Path, dest: &Path) -> CoreResult<u64> {
+    let mut source = File::open(blob)
+        .map_err(|e| CoreError::internal(format!("open {}: {e}", blob.display())))?;
+    let mut out = std::fs::OpenOptions::new()
+        .write(true)
+        .create_new(true)
+        .open(dest)
+        .map_err(|e| match e.kind() {
+            std::io::ErrorKind::AlreadyExists => {
+                CoreError::invalid(format!("{} already exists", dest.display()))
+            }
+            _ => CoreError::internal(format!("create {}: {e}", dest.display())),
+        })?;
+    std::io::copy(&mut source, &mut out)
+        .and_then(|written| out.flush().and(out.sync_all()).map(|()| written))
+        .map_err(|e| CoreError::internal(format!("write {}: {e}", dest.display())))
+}
+
+/// The staged blob of an op that carries file content.
+fn exportable(op: &PendingOp) -> Option<&Path> {
+    matches!(op.kind.as_str(), OP_CREATE | OP_REVISION)
+        .then_some(op.blob_path.as_deref())
+        .flatten()
+        .map(Path::new)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn op(kind: &str, blob: Option<&str>) -> PendingOp {
+        PendingOp {
+            id: 1,
+            kind: kind.to_string(),
+            uid: "vol~a".to_string(),
+            parent_uid: None,
+            name: None,
+            blob_path: blob.map(str::to_string),
+            meta_json: None,
+            created_at: 0,
+            attempts: 0,
+            last_error: None,
+            next_attempt_at: 0,
+        }
+    }
+
+    #[test]
+    fn only_a_change_that_carries_file_content_can_be_exported() {
+        assert!(exportable(&op(OP_CREATE, Some("/staging/a"))).is_some());
+        assert!(exportable(&op(OP_REVISION, Some("/staging/a"))).is_some());
+        assert!(exportable(&op(OP_CREATE, None)).is_none());
+        assert!(exportable(&op(OP_RENAME, None)).is_none());
+        assert!(exportable(&op(OP_TRASH, None)).is_none());
+    }
+
+    #[test]
+    fn an_export_copies_the_bytes_and_never_replaces_a_file() {
+        let dir = std::env::temp_dir().join(format!("pdfs-export-{}", std::process::id()));
+        std::fs::create_dir_all(&dir).unwrap();
+        let blob = dir.join("blob");
+        std::fs::write(&blob, b"queued bytes").unwrap();
+
+        let dest = dir.join("copy.txt");
+        assert_eq!(copy_to_new_file(&blob, &dest).unwrap(), 12);
+        assert_eq!(std::fs::read(&dest).unwrap(), b"queued bytes");
+
+        std::fs::write(&dest, b"the user's own").unwrap();
+        assert!(copy_to_new_file(&blob, &dest).is_err());
+        assert_eq!(std::fs::read(&dest).unwrap(), b"the user's own");
+        // The staged blob is the only copy of the change: an export leaves it.
+        assert_eq!(std::fs::read(&blob).unwrap(), b"queued bytes");
+
+        let _ = std::fs::remove_dir_all(&dir);
+    }
 }

crates/pdfs-fuse/src/reads.rs

@@ -70,7 +70,7 @@ const MAX_OPEN_READERS: usize = 64;
 /// `(mtime, size)` — the same validity pair the content cache uses (a new
 /// revision bumps mtime). On a mismatch the reader is dropped and reopened.
 pub(super) struct CachedReader {
-    reader: Arc<RevisionReader>,
+    reader: Arc<dyn RevisionRead>,
     mtime: i64,
     size: u64,
     /// For LRU eviction.
@@ -101,7 +101,7 @@ pub(super) struct PendingOpen {
     /// must not join this open — it would get a reader for the wrong bytes.
     mtime: i64,
     size: u64,
-    rx: tokio::sync::watch::Receiver<Option<Result<Arc<RevisionReader>, Errno>>>,
+    rx: tokio::sync::watch::Receiver<Option<Result<Arc<dyn RevisionRead>, Errno>>>,
 }
 
 /// Distinguishes `PendingOpen`s. Only uniqueness matters, so a plain counter
@@ -313,16 +313,16 @@ impl Core {
         uid: &NodeUid,
         mtime: i64,
         fsize: u64,
-    ) -> Result<Arc<RevisionReader>, Errno> {
+    ) -> Result<Arc<dyn RevisionRead>, Errno> {
         loop {
             // Decide under the lock, act outside it — network I/O must never run
             // under a std `Mutex`, and an await must never hold one.
             enum Act {
-                Hit(Arc<RevisionReader>),
+                Hit(Arc<dyn RevisionRead>),
-                Join(tokio::sync::watch::Receiver<Option<Result<Arc<RevisionReader>, Errno>>>),
+                Join(tokio::sync::watch::Receiver<Option<Result<Arc<dyn RevisionRead>, Errno>>>),
                 Lead(
                     u64,
-                    tokio::sync::watch::Sender<Option<Result<Arc<RevisionReader>, Errno>>>,
+                    tokio::sync::watch::Sender<Option<Result<Arc<dyn RevisionRead>, Errno>>>,
                 ),
             }
             let act = {
@@ -376,8 +376,8 @@ impl Core {
                 }
                 Act::Lead(id, tx) => {
                     debug!(%uid, mtime, fsize, "opening revision");
-                    let result = match self.client.open_revision(uid).await {
+                    let result = match self.drive.open_revision(uid).await {
-                        Ok(reader) => Ok(Arc::new(reader)),
+                        Ok(reader) => Ok(reader),
                         Err(e) => {
                             self.lost_link(&e, "open a revision");
                             warn!(%uid, error = %e, "open_revision failed");
@@ -464,7 +464,7 @@ impl Core {
     /// it, and the [`BLOCK_SIZE`] assumption when it has not — which is every
     /// first read, because learning it means opening a `RevisionReader`, and
     /// opening one per read is precisely the per-file key derivation the block
-    /// cache exists to avoid (bugs.md B12, B85).
+    /// cache exists to avoid (`docs/BUGS.md` B12, B85).
     ///
     /// Being wrong here is not a correctness problem: `read_at` plans over the
     /// real sizes and clamps to what was asked for either way. It costs a
@@ -493,15 +493,20 @@ impl Core {
     ) -> Result<Vec<u8>, Errno> {
         // A queued write has not reached the remote yet, so the remote's current
         // revision is stale and the staged blob is the truth. Serve from it until
-        // the drain worker lands the upload (offline.md Phase 3).
+        // the drain worker lands the upload.
         if let Some(pending) = self.pending.lock().get(uid).cloned() {
             return self.read_pending(&pending, offset, len);
         }
         // A node created offline and never written has no blob and no remote: it
         // is an empty file, and asking the API about a `local~` uid would only
-        // earn a 404 (offline.md Phase 3b).
+        // earn a 404. Unless its create landed since the
+        // read looked: the landing moved the queued write to the uid Drive
+        // gave it, and the row says which (`docs/BUGS.md` B179).
         if is_local_uid(uid) {
-            return Ok(Vec::new());
+            return match self.landed_stand_in_uid(uid) {
+                Some(real) => self.read_range(&real, mtime, fsize, offset, len, cache_blocks),
+                None => Ok(Vec::new()),
+            };
         }
         self.read_range_remote(uid, mtime, fsize, offset, len, cache_blocks)
     }
@@ -568,7 +573,7 @@ impl Core {
     /// leader's claim is gone by then, so this cannot recurse.
     async fn fetch_block(
         &self,
-        reader: &Arc<RevisionReader>,
+        reader: &Arc<dyn RevisionRead>,
         uid: &NodeUid,
         mtime: i64,
         fsize: u64,
@@ -631,10 +636,10 @@ impl Core {
     ///
     /// A block that comes back shorter than the file's size says it must be is
     /// never served, cached or promoted: it is repaired from the whole-file
-    /// download, or the read fails. See [`Core::repair_block`] (bugs.md B84).
+    /// download, or the read fails. See [`Core::repair_block`] (`docs/BUGS.md` B84).
     async fn read_block(
         &self,
-        reader: &Arc<RevisionReader>,
+        reader: &Arc<dyn RevisionRead>,
         uid: &NodeUid,
         mtime: i64,
         fsize: u64,
@@ -646,7 +651,7 @@ impl Core {
         // file's boundaries are wrong, and the failure is not confined to short
         // reads: sizes that *overstate* a block shift every block after it and
         // return full-length reads of the wrong bytes. So a disagreement of any
-        // kind takes the file off the range path entirely (bugs.md B84).
+        // kind takes the file off the range path entirely (`docs/BUGS.md` B84).
         let bytes = if reader.size() != fsize {
             warn!(
                 %uid, bidx = span.idx, fsize,
@@ -659,7 +664,7 @@ impl Core {
             // Learned here rather than on a path of its own: this is where a
             // reader is open anyway, and recording the real geometry is what
             // lets the *next* read plan its blocks on the revision's own
-            // boundaries instead of the 4 MiB fallback (bugs.md B85).
+            // boundaries instead of the 4 MiB fallback (`docs/BUGS.md` B85).
             if cache_blocks {
                 self.cache
                     .store_block_geometry(uid, mtime, fsize, reader.block_sizes());
@@ -701,7 +706,7 @@ impl Core {
     /// The range path derives every block boundary from the revision's recorded
     /// block sizes. When those understate the file, reads come back short with
     /// no error anywhere, and the caller hands userspace a truncated file that
-    /// looks like a clean EOF (bugs.md B84). `download_file_to` does not do that
+    /// looks like a clean EOF (`docs/BUGS.md` B84). `download_file_to` does not do that
     /// arithmetic — it streams the block list — so it returns the whole file
     /// where the range path cannot, which is why pinning was the workaround.
     /// This does the same thing on the user's behalf, once, and the resulting
@@ -778,7 +783,7 @@ impl Core {
             error!(%uid, %error, "creating a scratch file for a repair download failed");
             Errno::EIO
         })?;
-        let outcome = self.client.download_file_to(uid, &mut file).await;
+        let outcome = self.drive.download_file_to(uid, &mut file).await;
         let stored = (|| {
             outcome.map_err(|error| {
                 warn!(%uid, %error, "repair download failed");
@@ -913,7 +918,7 @@ impl Core {
         let end = offset.saturating_add(len).min(fsize);
         let mut out = Vec::with_capacity((end - offset) as usize);
         // On the revision's own boundaries where they are known, and on the
-        // 4 MiB fallback where they are not (bugs.md B85).
+        // 4 MiB fallback where they are not (`docs/BUGS.md` B85).
         let wanted = self.block_geometry(uid, mtime, fsize).spans(offset, end);
         let (Some(&head), Some(&tail)) = (wanted.first(), wanted.last()) else {
             return Ok(out);
@@ -1033,7 +1038,7 @@ impl Core {
             // — the cache validates it on read, the network path in `read_block`
             // — so this refuses rather than quietly contributing fewer bytes
             // than the range covers, which is what turned a bad block into a
-            // truncated file (bugs.md B84).
+            // truncated file (`docs/BUGS.md` B84).
             if block.len() as u64 != span.len {
                 error!(
                     %uid, bidx = span.idx, len = block.len(), expected = span.len, fsize,

crates/pdfs-fuse/src/redate.rs

@@ -248,10 +248,7 @@ impl Core {
 
         let outcomes = self
             .rt
-            .block_on(
+            .block_on(self.drive.trash_nodes(std::slice::from_ref(&candidate.uid)))
-                self.client
-                    .trash_nodes(std::slice::from_ref(&candidate.uid)),
-            )
             .map_err(|e| CoreError::from_api(&e, "trash the mis-dated original"))?;
         if let Some((_, Err(e))) = outcomes.into_iter().next() {
             return Err(CoreError::from_api(&e, "trash the mis-dated original"));

crates/pdfs-fuse/src/relocate.rs

@@ -25,7 +25,6 @@ use proton_drive_rs::NodeKind;
 use proton_drive_rs::proton_sdk::ids::NodeUid;
 use tracing::{info, warn};
 
-use super::background::forget_and_notify;
 use super::sync::mirror_subtree_unsynced;
 use super::{Core, is_local_uid, parse_uid};
 
@@ -36,7 +35,7 @@ const MIRROR_LOCK_WAIT: Duration = Duration::from_secs(5);
 
 /// Where one side of a move lives.
 enum Place {
-    /// My files or an on-demand folder: a live inode space. `core` is rooted at
+    /// My files or an on-demand folder: a live FUSE mount. `core` is rooted at
     /// that mount and `rel` is relative to its mountpoint.
     Mounted { core: Box<Core>, rel: PathBuf },
     /// A mirror folder: a local directory kept in step by the sync engine.
@@ -142,7 +141,7 @@ impl Core {
     /// are absolute local paths and may be in different locations: My files,
     /// an on-demand folder, or a mirror folder. Returns the moved name.
     ///
-    /// Within one inode space this is [`Core::move_to`]. Across locations it
+    /// Within one mount this is [`Core::move_to`]. Across locations it
     /// is a server-side move followed by local bookkeeping; see the module
     /// documentation. Anything the move could lose is refused up front.
     pub(crate) fn move_between(&self, src: &Path, dest_parent: &Path) -> CoreResult<String> {
@@ -155,7 +154,7 @@ impl Core {
                 rel: dest_rel,
             },
         ) = (&source, &dest)
-            && Arc::ptr_eq(&core.state, &dest_core.state)
+            && Arc::ptr_eq(&core.root, &dest_core.root)
         {
             return core.move_to(rel, dest_rel);
         }
@@ -255,7 +254,7 @@ impl Core {
             )));
         }
 
-        if let Err(e) = self.rt.block_on(self.client.move_node(&src_uid, &dest_uid)) {
+        if let Err(e) = self.move_remote(&src_uid, &dest_uid) {
             if let Some((from, to)) = &renamed
                 && let Err(back) = std::fs::rename(to, from)
             {
@@ -265,7 +264,15 @@ impl Core {
             return Err(CoreError::from_api(&e, "move"));
         }
 
-        self.settle_source(&source, &src_uid, renamed.is_some(), &dest, &name, src);
+        self.settle_source(
+            &source,
+            &src_uid,
+            renamed.is_some(),
+            &dest,
+            &dest_uid,
+            &name,
+            src,
+        );
         self.settle_dest(&dest, &dest_uid, &name);
         drop(guards);
         if renamed.is_none()
@@ -429,22 +436,23 @@ impl Core {
     }
 
     /// Bring the source location level with a move Drive has made.
+    #[allow(clippy::too_many_arguments)]
     fn settle_source(
         &self,
         source: &Place,
         uid: &NodeUid,
         renamed: bool,
         dest: &Place,
+        dest_uid: &NodeUid,
         name: &str,
         src: &Path,
     ) {
         match source {
             Place::Mounted { core, rel } => {
-                // Forget it everywhere, so no mount keeps serving it under the
+                // Moved everywhere, so no mount keeps serving it under the old
-                // old path. The content cache is keyed by uid and stays valid.
+                // path and its row stays (`docs/BUGS.md` B117). The content
-                self.for_each_mount(|st, notify| {
+                // cache is keyed by uid and stays valid.
-                    forget_and_notify(st, notify, uid);
+                self.relocate_everywhere(uid, dest_uid, name);
-                });
                 core.invalidate_parent_listing(rel);
             }
             Place::Mirror { folder, rel } if renamed => {

crates/pdfs-fuse/src/revisions.rs

@@ -232,7 +232,7 @@ impl Core {
         let mut out = std::io::BufWriter::new(file);
         let written = match self
             .rt
-            .block_on(self.client.download_revision_to(uid, revision_id, &mut out))
+            .block_on(self.drive.download_revision_to(uid, revision_id, &mut out))
             .map_err(|e| CoreError::from_api(&e, "download revision"))
             .and_then(|()| {
                 use std::io::Write as _;

crates/pdfs-fuse/src/sharing.rs

@@ -21,7 +21,7 @@ use proton_drive_rs::{MemberRole, NodeKind};
 
 use proton_drive_rs::Node;
 
-use super::{Core, ROOT_INO, node_size, parse_uid, public_link_info, role_from_str, role_to_str};
+use super::{Core, node_size, parse_uid, public_link_info, role_from_str, role_to_str};
 
 /// A node from a *shared* listing as a [`DirEntry`].
 ///
@@ -75,6 +75,7 @@ fn shared_entry_of(core: &Core, n: Node) -> DirEntry {
         shared_by_unverified,
         trashed_at: 0,
         trashed_from: None,
+        issue: None,
     }
 }
 
@@ -463,7 +464,7 @@ impl Core {
         }
         let nodes = self
             .rt
-            .block_on(self.client.enumerate_nodes(&uids))
+            .block_on(self.drive.enumerate_nodes(&uids))
             .map_err(|e| CoreError::from_api(&e, "enumerate nodes"))?;
         Ok(nodes
             .into_iter()
@@ -481,14 +482,14 @@ impl Core {
             parse_uid(uid).ok_or_else(|| CoreError::invalid(format!("invalid uid: {uid}")))?;
         let child_uids = self
             .rt
-            .block_on(self.client.enumerate_folder_children_node_uids(&uid))
+            .block_on(self.drive.enumerate_folder_children_node_uids(&uid))
             .map_err(|e| CoreError::from_api(&e, "enumerate shared children"))?;
         if child_uids.is_empty() {
             return Ok(Vec::new());
         }
         let nodes = self
             .rt
-            .block_on(self.client.enumerate_nodes(&child_uids))
+            .block_on(self.drive.enumerate_nodes(&child_uids))
             .map_err(|e| CoreError::from_api(&e, "enumerate nodes"))?;
         Ok(nodes
             .into_iter()
@@ -509,7 +510,7 @@ impl Core {
             parse_uid(uid).ok_or_else(|| CoreError::invalid(format!("invalid uid: {uid}")))?;
         let node = self
             .rt
-            .block_on(self.client.get_node(&uid))
+            .block_on(self.drive.get_node(&uid))
             .map_err(|e| CoreError::from_api(&e, "get shared node"))?
             .ok_or_else(|| CoreError::not_found("shared node not found"))?;
         if !node.is_file() {
@@ -610,7 +611,7 @@ impl Core {
     /// Proton products (not Drive-only). A remote round-trip; nothing here is
     /// cached.
     pub(crate) fn account_quota(&self) -> CoreResult<(i64, i64)> {
-        let q = self.block_on_bounded(self.client.quota()).map_err(|e| {
+        let q = self.block_on_bounded(self.drive.quota()).map_err(|e| {
             self.lost_link(&e, "account quota");
             CoreError::from_api(&e, "account quota")
         })?;
@@ -659,6 +660,12 @@ impl Core {
     /// the shared uids; the per-node detail is then gathered best-effort — a single
     /// node racing with an unshare drops from the list rather than failing the whole
     /// request.
+    ///
+    /// A share with no member, no invitation and no link is left out: it is
+    /// shared with no one. Stop Sharing leaves exactly that behind, since the SDK
+    /// cannot delete a share, and Drive keeps listing it until its backend gets
+    /// round to removing it, minutes later. A share whose details could not all
+    /// be read stays listed, so a failed lookup never hides a live share.
     pub(crate) fn list_shared_by_me(&self) -> CoreResult<Vec<SharedItem>> {
         let uids = self
             .rt
@@ -669,7 +676,7 @@ impl Core {
         }
         let nodes = self
             .rt
-            .block_on(self.client.enumerate_nodes(&uids))
+            .block_on(self.drive.enumerate_nodes(&uids))
             .map_err(|e| CoreError::from_api(&e, "enumerate nodes"))?;
         let mut items = Vec::with_capacity(nodes.len());
         for n in nodes {
@@ -677,24 +684,26 @@ impl Core {
             let members = self
                 .rt
                 .block_on(self.client.list_share_members(&uid))
-                .map(|m| m.len())
+                .map(|m| m.len());
-                .unwrap_or(0);
             let proton_invites = self
                 .rt
                 .block_on(self.client.list_share_invitations(&uid))
-                .map(|i| i.len())
+                .map(|i| i.len());
-                .unwrap_or(0);
             let external_invites = self
                 .rt
                 .block_on(self.client.list_external_invitations(&uid))
-                .map(|i| i.len())
+                .map(|i| i.len());
-                .unwrap_or(0);
+            let link = self.rt.block_on(self.client.get_public_link(&uid));
-            let link = self
+            if let (Ok(0), Ok(0), Ok(0), Ok(None)) =
-                .rt
+                (&members, &proton_invites, &external_invites, &link)
-                .block_on(self.client.get_public_link(&uid))
+            {
-                .ok()
+                debug!(%uid, "shared by me: skipping an emptied share");
-                .flatten()
+                continue;
-                .map(public_link_info);
+            }
+            let members = members.unwrap_or(0);
+            let proton_invites = proton_invites.unwrap_or(0);
+            let external_invites = external_invites.unwrap_or(0);
+            let link = link.ok().flatten().map(public_link_info);
             items.push(SharedItem {
                 uid: uid.to_string(),
                 is_dir: n.is_folder(),
@@ -714,19 +723,10 @@ impl Core {
     /// been seen through the mount (e.g. shared but not browsed to this session) —
     /// the caller then leaves the path empty.
     pub(crate) fn rel_path_for_uid(&self, uid: &NodeUid) -> Option<String> {
-        // Searched across every mount: a node browsed through a sync folder is
+        // Relative to whichever root the node sits under: a node browsed
-        // interned in that fork's inode space, so the primary state alone had no
+        // through a sync folder is under that fork's root, not My Files
-        // entry for it and the caller silently showed an empty path
+        // (`docs/BUGS.md` B74).
-        // (`docs/BUGS.md` B74). The path is relative to whichever mount holds
+        walk_to_root(&self.state(), uid)
-        // it, which is the one the user reached it through.
-        let mut path = None;
-        self.for_each_state(|st| {
-            if path.is_some() {
-                return;
-            }
-            path = walk_to_root(st, uid);
-        });
-        path
     }
 }
 
@@ -771,14 +771,18 @@ impl StopSharingOutcome {
     }
 }
 
-/// Walk one inode space from `uid` up to its root, building the path. `None` if
+/// Walk the tree from `uid` up to the root it sits under, building the path.
-/// that mount has never interned the node, or if the chain breaks partway —
+/// `None` if the node has never been interned, or if the chain breaks partway —
 /// a broken chain is a missing path, never a partial one.
 fn walk_to_root(st: &super::State, uid: &NodeUid) -> Option<String> {
     let mut ino = *st.by_uid.get(uid)?;
     let mut parts = Vec::new();
-    while ino != ROOT_INO {
+    while !st.roots.contains(&ino) {
         let entry = st.entries.get(&ino)?;
+        // An orphan is its own parent without being a root.
+        if entry.parent == ino {
+            return None;
+        }
         parts.push(entry.node.name.clone());
         ino = entry.parent;
     }

crates/pdfs-fuse/src/shutdown.rs

@@ -6,7 +6,7 @@
 //! invisible; in an in-process remount — which is how the daemon recovers from a
 //! mount going away underneath it — it leaks a whole generation of threads that
 //! keep writing to the database and calling the API on behalf of a mount that no
-//! longer exists (bugs.md B44).
+//! longer exists (`docs/BUGS.md` B44).
 //!
 //! The primitive is deliberately small: a flag plus a condvar. Every loop that
 //! would otherwise call `thread::sleep` calls [`Shutdown::sleep`] instead, which

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

@@ -0,0 +1,9 @@
+//! The simulation tests of `docs/TESTING.md`: a fake Drive with
+//! the faults the real one has, and the tools to drive daemons against it.
+
+pub(crate) mod daemon;
+pub(crate) mod fake_drive;
+pub(crate) mod model;
+pub(crate) mod rng;
+pub(crate) mod run;
+pub(crate) mod watchdog;

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

@@ -0,0 +1,445 @@
+//! The reference file system of the simulation (`docs/TESTING.md`,
+//! "Simulation runs", property 1): what each syscall a simulated client makes should
+//! answer, and the tree it should leave, on a POSIX file system.
+//!
+//! A [`Model`] covers one client's own folder; paths are relative to it. The
+//! same type is used for the trees read back from a mount and from Drive.
+
+use std::collections::BTreeMap;
+
+use super::rng::Rng;
+
+/// A tree by path: `None` is a folder, `Some` a file's content.
+pub(crate) type Tree = BTreeMap<String, Option<Vec<u8>>>;
+
+/// One file system call, or the few a program makes in a row.
+#[derive(Clone, Debug)]
+pub(crate) enum FsOp {
+    /// `open(O_CREAT | O_TRUNC)`, write `data`, close.
+    Create {
+        path: String,
+        data: Vec<u8>,
+    },
+    /// Open an existing file, write `data` at `offset` (past the end leaves
+    /// a hole), close.
+    Write {
+        path: String,
+        offset: u64,
+        data: Vec<u8>,
+    },
+    /// Open an existing file and `ftruncate` it to `len`.
+    Truncate {
+        path: String,
+        len: u64,
+    },
+    Mkdir {
+        path: String,
+    },
+    Rename {
+        from: String,
+        to: String,
+    },
+    Unlink {
+        path: String,
+    },
+    /// Open a file, unlink it, append `data`, read it all back, close.
+    UnlinkOpen {
+        path: String,
+        data: Vec<u8>,
+    },
+    Rmdir {
+        path: String,
+    },
+}
+
+impl FsOp {
+    /// The paths the op names, for the log.
+    pub(crate) fn describe(&self) -> String {
+        match self {
+            FsOp::Create { path, data } => format!("create {path} ({} bytes)", data.len()),
+            FsOp::Write { path, offset, data } => {
+                format!("write {path} at {offset} ({} bytes)", data.len())
+            }
+            FsOp::Truncate { path, len } => format!("truncate {path} to {len}"),
+            FsOp::Mkdir { path } => format!("mkdir {path}"),
+            FsOp::Rename { from, to } => format!("rename {from} -> {to}"),
+            FsOp::Unlink { path } => format!("unlink {path}"),
+            FsOp::UnlinkOpen { path, data } => {
+                format!("unlink {path} while open, then append {} bytes", data.len())
+            }
+            FsOp::Rmdir { path } => format!("rmdir {path}"),
+        }
+    }
+}
+
+/// The tree one client should have, and what its syscalls should answer.
+#[derive(Clone, Debug, Default)]
+pub(crate) struct Model {
+    tree: Tree,
+}
+
+/// Names are drawn from small pools, so ops collide: a create over an existing
+/// file, a rename over another, a mkdir of a name that is taken.
+const FILE_NAMES: [&str; 6] = ["a.txt", "b.txt", "c.bin", "d", "e.md", "f.txt"];
+const DIR_NAMES: [&str; 3] = ["x", "y", "z"];
+
+impl Model {
+    pub(crate) fn tree(&self) -> &Tree {
+        &self.tree
+    }
+
+    pub(crate) fn content(&self, path: &str) -> Option<&Vec<u8>> {
+        self.tree.get(path)?.as_ref()
+    }
+
+    /// What `op` should answer on a POSIX file system, applying it on success.
+    pub(crate) fn apply(&mut self, op: &FsOp) -> Result<(), i32> {
+        match op {
+            FsOp::Create { path, data } => {
+                self.check_parent(path)?;
+                match self.tree.get(path) {
+                    Some(None) => Err(libc::EISDIR),
+                    _ => {
+                        self.tree.insert(path.clone(), Some(data.clone()));
+                        Ok(())
+                    }
+                }
+            }
+            FsOp::Write { path, offset, data } => {
+                let content = self.file_mut(path)?;
+                // Writing nothing changes nothing, even past the end.
+                if data.is_empty() {
+                    return Ok(());
+                }
+                let end = *offset as usize + data.len();
+                if content.len() < end {
+                    content.resize(end, 0);
+                }
+                content[*offset as usize..end].copy_from_slice(data);
+                Ok(())
+            }
+            FsOp::Truncate { path, len } => {
+                self.file_mut(path)?.resize(*len as usize, 0);
+                Ok(())
+            }
+            FsOp::Mkdir { path } => {
+                self.check_parent(path)?;
+                if self.tree.contains_key(path) {
+                    return Err(libc::EEXIST);
+                }
+                self.tree.insert(path.clone(), None);
+                Ok(())
+            }
+            FsOp::Rename { from, to } => self.rename(from, to),
+            FsOp::Unlink { path } | FsOp::UnlinkOpen { path, .. } => {
+                self.check_parent(path)?;
+                match self.tree.get(path) {
+                    None => Err(libc::ENOENT),
+                    Some(None) => Err(libc::EISDIR),
+                    Some(Some(_)) => {
+                        self.tree.remove(path);
+                        Ok(())
+                    }
+                }
+            }
+            FsOp::Rmdir { path } => {
+                self.check_parent(path)?;
+                match self.tree.get(path) {
+                    None => Err(libc::ENOENT),
+                    Some(Some(_)) => Err(libc::ENOTDIR),
+                    Some(None) if self.has_children(path) => Err(libc::ENOTEMPTY),
+                    Some(None) => {
+                        self.tree.remove(path);
+                        Ok(())
+                    }
+                }
+            }
+        }
+    }
+
+    fn rename(&mut self, from: &str, to: &str) -> Result<(), i32> {
+        self.check_parent(from)?;
+        let Some(moving) = self.tree.get(from).cloned() else {
+            return Err(libc::ENOENT);
+        };
+        self.check_parent(to)?;
+        if from == to {
+            return Ok(());
+        }
+        if is_below(to, from) {
+            return Err(libc::EINVAL);
+        }
+        match (&moving, self.tree.get(to)) {
+            (None, Some(Some(_))) => return Err(libc::ENOTDIR),
+            (Some(_), Some(None)) => return Err(libc::EISDIR),
+            (None, Some(None)) if self.has_children(to) => return Err(libc::ENOTEMPTY),
+            _ => {}
+        }
+        let below: Vec<(String, Option<Vec<u8>>)> = self
+            .tree
+            .iter()
+            .filter(|(path, _)| is_below(path, from))
+            .map(|(path, entry)| (path.clone(), entry.clone()))
+            .collect();
+        self.tree.remove(from);
+        self.tree.insert(to.to_owned(), moving);
+        for (path, entry) in below {
+            self.tree.remove(&path);
+            self.tree
+                .insert(format!("{to}{}", &path[from.len()..]), entry);
+        }
+        Ok(())
+    }
+
+    fn file_mut(&mut self, path: &str) -> Result<&mut Vec<u8>, i32> {
+        self.check_parent(path)?;
+        match self.tree.get_mut(path) {
+            None => Err(libc::ENOENT),
+            Some(None) => Err(libc::EISDIR),
+            Some(Some(content)) => Ok(content),
+        }
+    }
+
+    fn check_parent(&self, path: &str) -> Result<(), i32> {
+        let mut at = String::new();
+        let mut names = path.split('/').peekable();
+        while let Some(name) = names.next() {
+            if names.peek().is_none() {
+                break;
+            }
+            if !at.is_empty() {
+                at.push('/');
+            }
+            at.push_str(name);
+            match self.tree.get(&at) {
+                None => return Err(libc::ENOENT),
+                Some(Some(_)) => return Err(libc::ENOTDIR),
+                Some(None) => {}
+            }
+        }
+        Ok(())
+    }
+
+    fn has_children(&self, path: &str) -> bool {
+        self.tree.keys().any(|other| is_below(other, path))
+    }
+
+    pub(crate) fn files(&self) -> Vec<&String> {
+        self.tree
+            .iter()
+            .filter(|(_, entry)| entry.is_some())
+            .map(|(path, _)| path)
+            .collect()
+    }
+
+    /// Folders, the client's own root (`""`) first.
+    fn dirs(&self) -> Vec<String> {
+        std::iter::once(String::new())
+            .chain(
+                self.tree
+                    .iter()
+                    .filter(|(_, entry)| entry.is_none())
+                    .map(|(path, _)| path.clone()),
+            )
+            .collect()
+    }
+
+    /// A random op, mostly one that should succeed.
+    pub(crate) fn next_op(&self, rng: &mut Rng) -> FsOp {
+        let dirs = self.dirs();
+        let files = self.files();
+        let in_dir = |rng: &mut Rng, names: &[&str]| {
+            let parent = rng.pick(&dirs).expect("the root is always there");
+            join(parent, rng.pick(names).expect("names"))
+        };
+        let a_file = |rng: &mut Rng| rng.pick(&files).map(|path| (*path).clone());
+        let roll = rng.below(100);
+        let op = match roll {
+            0..30 => Some(FsOp::Create {
+                path: in_dir(rng, &FILE_NAMES),
+                data: data(rng),
+            }),
+            30..45 => a_file(rng).map(|path| {
+                let len = self.content(&path).map_or(0, Vec::len) as u64;
+                FsOp::Write {
+                    offset: rng.below(len + 8),
+                    path,
+                    data: data(rng),
+                }
+            }),
+            45..50 => a_file(rng).map(|path| FsOp::Truncate {
+                len: rng.below(32),
+                path,
+            }),
+            50..60 => Some(FsOp::Mkdir {
+                path: in_dir(rng, &DIR_NAMES),
+            }),
+            // A rename in place, over another file as often as not.
+            60..72 => a_file(rng).map(|from| FsOp::Rename {
+                to: join(parent_of(&from), rng.pick(&FILE_NAMES).expect("names")),
+                from,
+            }),
+            // A move to another folder, renamed or not.
+            72..82 => a_file(rng).map(|from| {
+                let name = if rng.chance(0.5) {
+                    name_of(&from)
+                } else {
+                    rng.pick(&FILE_NAMES).expect("names")
+                };
+                let parent = rng.pick(&dirs).expect("the root is always there");
+                FsOp::Rename {
+                    to: join(parent, name),
+                    from,
+                }
+            }),
+            // A folder renamed or moved, with what is in it.
+            82..86 => {
+                let from = rng.pick(&dirs[1..]).cloned();
+                from.map(|from| FsOp::Rename {
+                    to: in_dir(rng, &DIR_NAMES),
+                    from,
+                })
+            }
+            86..94 => a_file(rng).map(|path| FsOp::Unlink { path }),
+            94..97 => a_file(rng).map(|path| FsOp::UnlinkOpen {
+                path,
+                data: data(rng),
+            }),
+            _ => rng
+                .pick(&dirs[1..])
+                .cloned()
+                .map(|path| FsOp::Rmdir { path }),
+        };
+        op.unwrap_or_else(|| FsOp::Create {
+            path: in_dir(rng, &FILE_NAMES),
+            data: data(rng),
+        })
+    }
+}
+
+/// Content for a write: short and recognisable, now and then empty.
+pub(crate) fn data(rng: &mut Rng) -> Vec<u8> {
+    let len = if rng.chance(0.1) {
+        0
+    } else {
+        rng.between(1, 48)
+    };
+    let tag = rng.next_u64();
+    (0..len).map(|i| b'a' + ((tag + i) % 26) as u8).collect()
+}
+
+pub(crate) fn join(parent: &str, name: &str) -> String {
+    if parent.is_empty() {
+        name.to_owned()
+    } else {
+        format!("{parent}/{name}")
+    }
+}
+
+pub(crate) fn parent_of(path: &str) -> &str {
+    path.rsplit_once('/').map_or("", |(parent, _)| parent)
+}
+
+pub(crate) fn name_of(path: &str) -> &str {
+    path.rsplit_once('/').map_or(path, |(_, name)| name)
+}
+
+fn is_below(path: &str, ancestor: &str) -> bool {
+    path.len() > ancestor.len() + 1
+        && path.starts_with(ancestor)
+        && path.as_bytes()[ancestor.len()] == b'/'
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn create(path: &str, data: &[u8]) -> FsOp {
+        FsOp::Create {
+            path: path.into(),
+            data: data.to_vec(),
+        }
+    }
+
+    #[test]
+    fn a_rename_over_a_file_replaces_it_and_a_folder_moves_with_its_contents() {
+        let mut model = Model::default();
+        model.apply(&FsOp::Mkdir { path: "x".into() }).unwrap();
+        model.apply(&create("x/a", b"1")).unwrap();
+        model.apply(&create("b", b"2")).unwrap();
+        model
+            .apply(&FsOp::Rename {
+                from: "b".into(),
+                to: "x/a".into(),
+            })
+            .unwrap();
+        assert_eq!(model.content("x/a"), Some(&b"2".to_vec()));
+        model
+            .apply(&FsOp::Rename {
+                from: "x".into(),
+                to: "y".into(),
+            })
+            .unwrap();
+        assert_eq!(model.tree().keys().collect::<Vec<_>>(), vec!["y", "y/a"]);
+    }
+
+    #[test]
+    fn calls_fail_the_way_posix_says() {
+        let mut model = Model::default();
+        model.apply(&FsOp::Mkdir { path: "x".into() }).unwrap();
+        model.apply(&create("x/a", b"1")).unwrap();
+        assert_eq!(
+            model.apply(&FsOp::Mkdir { path: "x".into() }),
+            Err(libc::EEXIST)
+        );
+        assert_eq!(model.apply(&create("x", b"")), Err(libc::EISDIR));
+        assert_eq!(model.apply(&create("x/a/b", b"")), Err(libc::ENOTDIR));
+        assert_eq!(model.apply(&create("q/a", b"")), Err(libc::ENOENT));
+        assert_eq!(
+            model.apply(&FsOp::Rmdir { path: "x".into() }),
+            Err(libc::ENOTEMPTY)
+        );
+        assert_eq!(
+            model.apply(&FsOp::Unlink { path: "x".into() }),
+            Err(libc::EISDIR)
+        );
+        let into_itself = FsOp::Rename {
+            from: "x".into(),
+            to: "x/y".into(),
+        };
+        assert_eq!(model.apply(&into_itself), Err(libc::EINVAL));
+    }
+
+    #[test]
+    fn a_write_past_the_end_leaves_a_hole() {
+        let mut model = Model::default();
+        model.apply(&create("a", b"ab")).unwrap();
+        let write = FsOp::Write {
+            path: "a".into(),
+            offset: 4,
+            data: b"z".to_vec(),
+        };
+        model.apply(&write).unwrap();
+        assert_eq!(model.content("a"), Some(&b"ab\0\0z".to_vec()));
+        let nothing = FsOp::Write {
+            path: "a".into(),
+            offset: 9,
+            data: Vec::new(),
+        };
+        model.apply(&nothing).unwrap();
+        assert_eq!(model.content("a"), Some(&b"ab\0\0z".to_vec()));
+    }
+
+    #[test]
+    fn generated_ops_mostly_succeed() {
+        let mut rng = Rng::new(9);
+        let mut model = Model::default();
+        let ok = (0..500)
+            .filter(|_| {
+                let op = model.next_op(&mut rng);
+                model.apply(&op).is_ok()
+            })
+            .count();
+        assert!(ok > 350, "{ok} of 500 succeeded");
+    }
+}

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

@@ -0,0 +1,79 @@
+//! A small seeded random number generator, so a failing simulation is a seed
+//! that can be replayed. SplitMix64: fast, good enough for choosing operations
+//! and faults, and no dependency.
+
+#[derive(Clone, Debug)]
+pub(crate) struct Rng(u64);
+
+impl Rng {
+    pub(crate) fn new(seed: u64) -> Self {
+        Self(seed)
+    }
+
+    pub(crate) fn next_u64(&mut self) -> u64 {
+        self.0 = self.0.wrapping_add(0x9E37_79B9_7F4A_7C15);
+        let mut z = self.0;
+        z = (z ^ (z >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
+        z = (z ^ (z >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
+        z ^ (z >> 31)
+    }
+
+    /// A value in `0..n`; `0` when `n` is `0`.
+    pub(crate) fn below(&mut self, n: u64) -> u64 {
+        if n == 0 { 0 } else { self.next_u64() % n }
+    }
+
+    /// A value in `lo..=hi`.
+    pub(crate) fn between(&mut self, lo: u64, hi: u64) -> u64 {
+        lo + self.below(hi.saturating_sub(lo) + 1)
+    }
+
+    /// True with probability `p`.
+    pub(crate) fn chance(&mut self, p: f64) -> bool {
+        p > 0.0 && (self.next_u64() >> 11) as f64 / (1u64 << 53) as f64 <= p
+    }
+
+    pub(crate) fn pick<'a, T>(&mut self, items: &'a [T]) -> Option<&'a T> {
+        items.get(self.below(items.len() as u64) as usize)
+    }
+
+    /// A child generator, so one consumer's draws do not shift another's.
+    pub(crate) fn fork(&mut self) -> Self {
+        Self::new(self.next_u64())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Rng;
+
+    #[test]
+    fn a_seed_replays_the_same_sequence() {
+        let (mut a, mut b) = (Rng::new(7), Rng::new(7));
+        for _ in 0..100 {
+            assert_eq!(a.next_u64(), b.next_u64());
+        }
+        assert_ne!(Rng::new(7).next_u64(), Rng::new(8).next_u64());
+    }
+
+    #[test]
+    fn bounded_draws_stay_in_range() {
+        let mut rng = Rng::new(1);
+        for _ in 0..1000 {
+            assert!(rng.below(5) < 5);
+            assert!((3..=9).contains(&rng.between(3, 9)));
+        }
+        assert_eq!(rng.below(0), 0);
+        assert!(!rng.chance(0.0));
+        assert!(rng.chance(1.0));
+        assert!([1, 2, 3].contains(rng.pick(&[1, 2, 3]).unwrap()));
+        assert_eq!(rng.pick::<u8>(&[]), None);
+    }
+
+    #[test]
+    fn a_fork_draws_apart_from_its_parent() {
+        let mut parent = Rng::new(3);
+        let mut child = parent.fork();
+        assert_ne!(parent.next_u64(), child.next_u64());
+    }
+}

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

@@ -0,0 +1,766 @@
+//! The simulation runs described in `docs/TESTING.md`.
+//!
+//! A run starts one or more daemons on a shared [`FakeDrive`], each owning a
+//! folder `c<n>` that only it writes, so there is one writer per file. A seed
+//! draws a sequence of steps: syscalls through a client's mount, the link of a
+//! client going down or up, a client restarting, a pause, a settle (every
+//! queue must drain within a budget), or a file deleted while the drain holds
+//! a write to it. Every syscall is checked against the
+//! client's [`Model`] as it happens. After the sequence every link comes up
+//! and the run checks:
+//!
+//! 1. **No loss** and **POSIX**: Drive's copy of each client's folder is what
+//!    its model says.
+//! 2. **No false conflicts**: no conflict copy anywhere, and the drain never
+//!    takes a client's own delete for another device's.
+//! 3. **Convergence**: each mount shows Drive's tree.
+//! 4. **Liveness**: no syscall took longer than its budget, settles drained in
+//!    theirs, and every queue drained once the links were up. A call that
+//!    never returns is caught by the [`Watchdog`], which keeps the stacks.
+//!
+//! A restart here is a stop and a start: the next run finds what the last
+//! one wrote down, but in-flight work is let finish rather than cut. A kill
+//! at an arbitrary point needs the daemon in a process of its own.
+//!
+//! Any of these fails the seed. No open bug is tolerated: the matchers that
+//! counted the ones still open instead (B125 to B134) went once a run on
+//! 812eb3d passed every profile without them.
+//!
+//! The runs are ignored by default because they mount FUSE; run them with
+//! `cargo test -p pdfs-fuse --lib sim::run -- --ignored --test-threads=1`.
+//! `PDFS_SIM_SEEDS=n` sets how many seeds each runs, `PDFS_SIM_SEED=s` replays
+//! one, and `RUST_LOG=pdfs_fuse=debug` with `--nocapture` shows the daemons'
+//! logs.
+
+use std::fs::OpenOptions;
+use std::io::{self, Read, Seek, SeekFrom, Write};
+use std::path::{Path, PathBuf};
+use std::time::{Duration, Instant};
+
+use super::daemon::{Daemon, scratch, take_logged, wait_until};
+use super::fake_drive::{Entry, FakeDrive, Faults};
+use super::model::{FsOp, Model, Tree, data, join};
+use super::rng::Rng;
+use super::watchdog::Watchdog;
+
+/// What a run looks like.
+pub(crate) struct Profile {
+    pub(crate) name: &'static str,
+    pub(crate) clients: usize,
+    pub(crate) steps: usize,
+    pub(crate) faults: fn() -> Faults,
+    /// Whether links go down and come back during the sequence.
+    pub(crate) link_flaps: bool,
+    pub(crate) restarts: bool,
+    /// Whether files are deleted while the drain holds a write to them.
+    pub(crate) deletes_mid_upload: bool,
+    /// How long a settle may take; `None` leaves settles out.
+    pub(crate) settle_budget: Option<Duration>,
+    /// How long one syscall may take.
+    pub(crate) syscall_budget: Duration,
+    /// How long the queues may take to drain at the end.
+    pub(crate) drain_budget: Duration,
+}
+
+/// How long the mounts may take to show Drive's tree at the end: one event
+/// poll (`POLL_INTERVAL`) and change.
+const CONVERGE_BUDGET: Duration = Duration::from_secs(30);
+
+/// How long the drain may take to pick up a write: its debounce, and then
+/// some.
+const PICKUP_BUDGET: Duration = Duration::from_secs(8);
+
+/// Steps shown before a failure. All of them are written to `steps.log` in
+/// the state the failure keeps.
+const LOG_TAIL: usize = 40;
+
+/// How long past its own budget a step, or the checks after the last one, may
+/// run before the watchdog takes it for hung. Longer than a restart may wait
+/// for the last run and the mount.
+const STALL: Duration = Duration::from_secs(120);
+
+struct Client {
+    daemon: Option<Daemon>,
+    model: Model,
+    online: bool,
+}
+
+impl Client {
+    fn daemon(&self) -> &Daemon {
+        self.daemon
+            .as_ref()
+            .expect("a client always has a daemon between steps")
+    }
+
+    fn root(&self, index: usize) -> PathBuf {
+        self.daemon().mountpoint.join(owned_folder(index))
+    }
+}
+
+struct Run {
+    seed: u64,
+    profile: &'static Profile,
+    drive: std::sync::Arc<FakeDrive>,
+    clients: Vec<Client>,
+    log: Vec<String>,
+    started: Instant,
+    /// What the daemons logged at `INFO` and above so far.
+    logged: Vec<String>,
+    watchdog: Watchdog,
+}
+
+/// Run `profile` on `seed`. It answers a report of what went wrong, if
+/// anything did.
+pub(crate) fn run(seed: u64, profile: &'static Profile) -> Result<(), String> {
+    let dir = scratch(&format!("{}-{seed}", profile.name));
+    let mut rng = Rng::new(seed);
+    let drive = FakeDrive::new();
+    let mut run = Run {
+        seed,
+        profile,
+        drive: drive.clone(),
+        clients: Vec::new(),
+        log: Vec::new(),
+        started: Instant::now(),
+        logged: Vec::new(),
+        watchdog: Watchdog::new(&dir),
+    };
+    let outcome = run.execute(&dir, &mut rng);
+    run.watchdog.stop();
+    // A hang is what failed, whatever the aborted call answered.
+    let outcome = match run.watchdog.fired() {
+        Some(hung) => Err(format!("liveness: {}", hung.what)),
+        None => outcome,
+    };
+    for client in &mut run.clients {
+        if let Some(daemon) = client.daemon.take() {
+            let _ = daemon.stop();
+        }
+    }
+    match outcome {
+        Ok(()) => {
+            let _ = std::fs::remove_dir_all(&dir);
+            Ok(())
+        }
+        Err(failure) => Err(run.report(&failure, &dir)),
+    }
+}
+
+impl Run {
+    fn execute(&mut self, dir: &Path, rng: &mut Rng) -> Result<(), String> {
+        for index in 0..self.profile.clients {
+            let client = self.drive.client(rng.next_u64(), (self.profile.faults)());
+            let daemon = Daemon::start(&dir.join(format!("client{index}")), client)
+                .map_err(|error| format!("client {index} did not mount: {error}"))?;
+            let folder = daemon.mountpoint.join(owned_folder(index));
+            std::fs::create_dir(&folder)
+                .map_err(|error| format!("client {index}: mkdir {}: {error}", folder.display()))?;
+            self.clients.push(Client {
+                daemon: Some(daemon),
+                model: Model::default(),
+                online: true,
+            });
+        }
+        for step in 0..self.profile.steps {
+            let _watching = self.watchdog.arm(self.step_limit(), format!("step {step}"));
+            self.step(rng)?;
+        }
+        let _watching = self.watchdog.arm(
+            self.profile.drain_budget + STALL,
+            "the checks after the last step",
+        );
+        self.finish()
+    }
+
+    /// How long a step may run before the watchdog takes it for hung.
+    fn step_limit(&self) -> Duration {
+        let budget = self.profile.settle_budget.unwrap_or_default();
+        budget.max(self.profile.syscall_budget) + STALL
+    }
+
+    fn step(&mut self, rng: &mut Rng) -> Result<(), String> {
+        let index = rng.below(self.clients.len() as u64) as usize;
+        let roll = rng.below(100);
+        match roll {
+            0..4 if self.profile.link_flaps => {
+                let client = &mut self.clients[index];
+                client.online = !client.online;
+                client.daemon().client.set_online(client.online);
+                let state = if client.online { "up" } else { "down" };
+                self.note(format!("client {index}: link {state}"));
+            }
+            4..6 if self.profile.restarts => {
+                self.note(format!("client {index}: restart"));
+                let daemon = self.clients[index].daemon.take().expect("daemon");
+                let daemon = daemon
+                    .restart()
+                    .map_err(|error| format!("client {index} did not come back: {error}"))?;
+                self.clients[index].daemon = Some(daemon);
+            }
+            6..12 => {
+                let ms = rng.below(400);
+                self.note(format!("pause {ms} ms"));
+                std::thread::sleep(Duration::from_millis(ms));
+            }
+            12..15 => {
+                if let Some(budget) = self.profile.settle_budget
+                    && self.clients.iter().all(|client| client.online)
+                {
+                    self.settle(budget)?;
+                }
+            }
+            15..25 if self.profile.deletes_mid_upload => self.delete_mid_upload(index, rng)?,
+            _ => {
+                let op = self.clients[index].model.next_op(rng);
+                self.syscall(index, op)?;
+            }
+        }
+        Ok(())
+    }
+
+    /// Wait until every queue is empty and Drive holds what the models say.
+    fn settle(&mut self, budget: Duration) -> Result<(), String> {
+        self.note("settle".into());
+        let start = Instant::now();
+        // What the drain logs meanwhile is what explains a known bug's damage.
+        if !wait_until(budget, || {
+            self.logged.extend(take_logged());
+            self.landed()
+        }) {
+            return Err(format!(
+                "liveness: the queues did not drain within {budget:?}\n{}",
+                self.difference()
+            ));
+        }
+        self.note(format!("settled in {:?}", start.elapsed()));
+        Ok(())
+    }
+
+    /// Write a file Drive holds and delete it once the drain has picked the
+    /// write up. The drain's read of the node is held until the delete has
+    /// landed and a read shows it, so the drain finds the file trashed while
+    /// it holds a write that is no longer queued (B105). Half the time the
+    /// file is made again meanwhile, which queues a write under the op id the
+    /// delete freed (B133).
+    fn delete_mid_upload(&mut self, index: usize, rng: &mut Rng) -> Result<(), String> {
+        let file = rng
+            .pick(&self.clients[index].model.files())
+            .map(|path| (*path).clone());
+        let (Some(path), Some(budget), true) = (
+            file,
+            self.profile.settle_budget,
+            self.clients.iter().all(|client| client.online),
+        ) else {
+            let op = self.clients[index].model.next_op(rng);
+            return self.syscall(index, op);
+        };
+        self.settle(budget)?;
+        let Some(uid) = self.drive.lookup(&join(&owned_folder(index), &path)) else {
+            return Err(format!(
+                "no loss: client {index}'s {path} is not on Drive after a settle"
+            ));
+        };
+        let held = self.clients[index].daemon().client.hold_next_read(&uid);
+        self.note(format!("client {index}: hold the next read of {path}"));
+        let mut bytes = data(rng);
+        bytes.push(b'.');
+        self.syscall(
+            index,
+            FsOp::Write {
+                path: path.clone(),
+                offset: 0,
+                data: bytes,
+            },
+        )?;
+        if !wait_until(PICKUP_BUDGET, || held.reached()) {
+            self.note(format!("client {index}: nothing read {path} back"));
+            return Ok(());
+        }
+        self.syscall(index, FsOp::Unlink { path: path.clone() })?;
+        if rng.chance(0.5) {
+            self.syscall(
+                index,
+                FsOp::Create {
+                    path: path.clone(),
+                    data: data(rng),
+                },
+            )?;
+        }
+        let faults = (self.profile.faults)();
+        let latency = Duration::from_millis(faults.latency_ms.1);
+        std::thread::sleep(faults.listing_lag + latency);
+        drop(held);
+        self.note(format!("client {index}: the read of {path} goes on"));
+        // Nothing else is queued before the drain has answered.
+        std::thread::sleep(2 * latency + Duration::from_millis(50));
+        Ok(())
+    }
+
+    fn syscall(&mut self, index: usize, op: FsOp) -> Result<(), String> {
+        let client = &mut self.clients[index];
+        let root = client.root(index);
+        let before = client.model.content(target(&op)).cloned();
+        let expected = client.model.apply(&op);
+        self.logged.extend(take_logged());
+        let start = Instant::now();
+        let actual = perform(&root, &op, before.as_deref());
+        let took = start.elapsed();
+        self.note(format!(
+            "client {index}: {} = {} in {took:?}",
+            op.describe(),
+            outcome(&actual)
+        ));
+        let actual = actual?;
+        self.logged.extend(take_logged());
+        if actual != expected {
+            return Err(format!(
+                "posix: client {index}: {} answered {}, expected {}",
+                op.describe(),
+                errno(actual),
+                errno(expected)
+            ));
+        }
+        if took > self.profile.syscall_budget {
+            return Err(format!(
+                "liveness: client {index}: {} took {took:?}, over {:?}",
+                op.describe(),
+                self.profile.syscall_budget
+            ));
+        }
+        Ok(())
+    }
+
+    fn finish(&mut self) -> Result<(), String> {
+        for client in &mut self.clients {
+            client.online = true;
+            client.daemon().client.set_online(true);
+        }
+        self.note("every link up; waiting for the queues".into());
+        if !wait_until(self.profile.drain_budget, || {
+            self.logged.extend(take_logged());
+            self.landed()
+        }) {
+            return Err(format!(
+                "no loss: Drive does not hold what the clients wrote, {:?} after the links came up\n{}",
+                self.profile.drain_budget,
+                self.difference()
+            ));
+        }
+        // Each client's folder is its own, so a file of it gone from Drive was
+        // deleted by the client.
+        if let Some(line) = self.logged.iter().find(|line| is_own_delete_kept(line)) {
+            return Err(format!(
+                "no false conflicts: the drain took a client's own delete for another device's: {line}"
+            ));
+        }
+        let drive = self.drive_tree();
+        let conflicts: Vec<String> = drive
+            .into_keys()
+            .filter(|path| is_conflict_copy(path))
+            .collect();
+        if !conflicts.is_empty() {
+            return Err(format!("no false conflicts: {conflicts:?}"));
+        }
+        for index in 0..self.clients.len() {
+            let mut last = Tree::new();
+            let converged = wait_until(CONVERGE_BUDGET, || {
+                last = read_tree(&self.clients[index].daemon().mountpoint);
+                last == self.drive_tree()
+            });
+            if !converged {
+                return Err(format!(
+                    "convergence: client {index}'s mount differs from Drive\n{}",
+                    diff(&last, &self.drive_tree(), "mount", "Drive")
+                ));
+            }
+        }
+        Ok(())
+    }
+
+    /// Whether every client's queue is empty and Drive holds what its model
+    /// says.
+    fn landed(&self) -> bool {
+        let drive = self.drive_tree();
+        self.clients.iter().enumerate().all(|(index, client)| {
+            client
+                .daemon()
+                .pending()
+                .is_ok_and(|items| items.is_empty())
+                && subtree(&drive, &owned_folder(index)) == *client.model.tree()
+        })
+    }
+
+    fn difference(&self) -> String {
+        let drive = self.drive_tree();
+        let mut out = String::new();
+        for (index, client) in self.clients.iter().enumerate() {
+            let pending = client.daemon().pending().unwrap_or_default();
+            for item in pending {
+                out.push_str(&format!(
+                    "  client {index} still owes: {} {} (attempts {}, last error {:?})\n",
+                    item.kind, item.path, item.attempts, item.last_error
+                ));
+            }
+            out.push_str(&diff(
+                client.model.tree(),
+                &subtree(&drive, &owned_folder(index)),
+                &format!("client {index}'s model"),
+                "Drive",
+            ));
+        }
+        out
+    }
+
+    fn drive_tree(&self) -> Tree {
+        self.drive
+            .tree()
+            .into_iter()
+            .map(|(path, entry)| {
+                let content = match entry {
+                    Entry::Folder => None,
+                    Entry::File(content) => Some(content.as_ref().clone()),
+                };
+                (path, content)
+            })
+            .collect()
+    }
+
+    fn note(&mut self, line: String) {
+        let line = format!("{:>8.3}s {line}", self.started.elapsed().as_secs_f64());
+        self.log.push(line);
+    }
+
+    fn report(&self, failure: &str, dir: &Path) -> String {
+        let _ = std::fs::write(dir.join("steps.log"), self.log.join("\n") + "\n");
+        let tail = &self.log[self.log.len().saturating_sub(LOG_TAIL)..];
+        format!(
+            "{} seed {} failed: {failure}\nreplay with PDFS_SIM_SEED={}; state kept in {}\nlast steps:\n{}",
+            self.profile.name,
+            self.seed,
+            self.seed,
+            dir.display(),
+            tail.join("\n")
+        )
+    }
+}
+
+/// Make `op` under `root`. The outer error is a check that failed on the
+/// way (the content an open file reads back), the inner one the errno.
+fn perform(root: &Path, op: &FsOp, before: Option<&[u8]>) -> Result<Result<(), i32>, String> {
+    let at = |path: &str| root.join(path);
+    let result: io::Result<()> = match op {
+        FsOp::Create { path, data } => std::fs::write(at(path), data),
+        FsOp::Write { path, offset, data } => OpenOptions::new()
+            .write(true)
+            .open(at(path))
+            .and_then(|mut file| {
+                file.seek(SeekFrom::Start(*offset))?;
+                file.write_all(data)
+            }),
+        FsOp::Truncate { path, len } => OpenOptions::new()
+            .write(true)
+            .open(at(path))
+            .and_then(|file| file.set_len(*len)),
+        FsOp::Mkdir { path } => std::fs::create_dir(at(path)),
+        FsOp::Rename { from, to } => std::fs::rename(at(from), at(to)),
+        FsOp::Unlink { path } => std::fs::remove_file(at(path)),
+        FsOp::Rmdir { path } => std::fs::remove_dir(at(path)),
+        FsOp::UnlinkOpen { path, data } => {
+            let mut read = Vec::new();
+            let result = OpenOptions::new()
+                .read(true)
+                .write(true)
+                .open(at(path))
+                .and_then(|mut file| {
+                    std::fs::remove_file(at(path))?;
+                    file.seek(SeekFrom::End(0))?;
+                    file.write_all(data)?;
+                    file.seek(SeekFrom::Start(0))?;
+                    file.read_to_end(&mut read).map(|_| ())
+                });
+            if result.is_ok() {
+                let expected = [before.unwrap_or_default(), data].concat();
+                if read != expected {
+                    return Err(format!(
+                        "posix: {} read back {:?}, expected {:?}",
+                        op.describe(),
+                        String::from_utf8_lossy(&read),
+                        String::from_utf8_lossy(&expected)
+                    ));
+                }
+            }
+            result
+        }
+    };
+    Ok(result.map_err(|error| error.raw_os_error().unwrap_or(libc::EIO)))
+}
+
+fn target(op: &FsOp) -> &str {
+    match op {
+        FsOp::Create { path, .. }
+        | FsOp::Write { path, .. }
+        | FsOp::Truncate { path, .. }
+        | FsOp::Mkdir { path }
+        | FsOp::Unlink { path }
+        | FsOp::UnlinkOpen { path, .. }
+        | FsOp::Rmdir { path } => path,
+        FsOp::Rename { from, .. } => from,
+    }
+}
+
+/// The tree a mount shows, read through it, without the folders it makes up
+/// that are not on Drive.
+fn read_tree(mountpoint: &Path) -> Tree {
+    fn walk(dir: &Path, prefix: &str, tree: &mut Tree) {
+        let Ok(entries) = std::fs::read_dir(dir) else {
+            return;
+        };
+        for entry in entries.flatten() {
+            let name = entry.file_name().to_string_lossy().into_owned();
+            if prefix.is_empty() && name == crate::r#virtual::SHARED_WITH_ME_BASE {
+                continue;
+            }
+            let path = super::model::join(prefix, &name);
+            if entry.file_type().is_ok_and(|kind| kind.is_dir()) {
+                tree.insert(path.clone(), None);
+                walk(&entry.path(), &path, tree);
+            } else {
+                tree.insert(path, std::fs::read(entry.path()).ok());
+            }
+        }
+    }
+    let mut tree = Tree::new();
+    walk(mountpoint, "", &mut tree);
+    tree
+}
+
+/// The part of `tree` below `folder`, relative to it.
+fn subtree(tree: &Tree, folder: &str) -> Tree {
+    let prefix = format!("{folder}/");
+    tree.iter()
+        .filter_map(|(path, entry)| Some((path.strip_prefix(&prefix)?.to_owned(), entry.clone())))
+        .collect()
+}
+
+fn owned_folder(index: usize) -> String {
+    format!("c{index}")
+}
+
+/// Whether `line` is the drain keeping a queued write as a conflict copy
+/// because Drive no longer holds the file, or holds it in the trash.
+fn is_own_delete_kept(line: &str) -> bool {
+    line.starts_with("queued write conflicts; keeping a conflict copy")
+        && (line.contains(" reason=\"the file was trashed remotely\"")
+            || line.contains(" reason=\"the file no longer exists remotely\""))
+}
+
+fn is_conflict_copy(path: &str) -> bool {
+    path.split('/')
+        .any(|name| name.contains("(sync-conflict") || name.starts_with("recovered-"))
+}
+
+fn diff(left: &Tree, right: &Tree, left_name: &str, right_name: &str) -> String {
+    let show = |entry: &Option<Vec<u8>>| match entry {
+        None => "folder".to_owned(),
+        Some(content) => format!("{:?}", String::from_utf8_lossy(content)),
+    };
+    let mut out = String::new();
+    for (path, entry) in left {
+        match right.get(path) {
+            None => out.push_str(&format!(
+                "  {path}: only in {left_name} ({})\n",
+                show(entry)
+            )),
+            Some(other) if other != entry => out.push_str(&format!(
+                "  {path}: {left_name} has {}, {right_name} has {}\n",
+                show(entry),
+                show(other)
+            )),
+            Some(_) => {}
+        }
+    }
+    for (path, entry) in right {
+        if !left.contains_key(path) {
+            out.push_str(&format!(
+                "  {path}: only in {right_name} ({})\n",
+                show(entry)
+            ));
+        }
+    }
+    out
+}
+
+fn errno(outcome: Result<(), i32>) -> String {
+    match outcome {
+        Ok(()) => "ok".into(),
+        Err(code) => io::Error::from_raw_os_error(code).to_string(),
+    }
+}
+
+fn outcome(actual: &Result<Result<(), i32>, String>) -> String {
+    match actual {
+        Ok(result) => errno(*result),
+        Err(check) => check.clone(),
+    }
+}
+
+/// Run `profile` over the seeds the environment asks for: `PDFS_SIM_SEED`
+/// alone, or `PDFS_SIM_SEEDS` of them (default `default_seeds`) from 1.
+pub(crate) fn run_seeds(profile: &'static Profile, default_seeds: u64) {
+    let seeds: Vec<u64> = match std::env::var("PDFS_SIM_SEED") {
+        Ok(seed) => vec![seed.parse().expect("PDFS_SIM_SEED is a number")],
+        Err(_) => {
+            let count = std::env::var("PDFS_SIM_SEEDS")
+                .ok()
+                .and_then(|count| count.parse().ok())
+                .unwrap_or(default_seeds);
+            (1..=count).collect()
+        }
+    };
+    let failures: Vec<String> = seeds
+        .into_iter()
+        .filter_map(|seed| run(seed, profile).err())
+        .collect();
+    assert!(failures.is_empty(), "\n{}", failures.join("\n\n"));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    static ONE_CLIENT_LAN: Profile = Profile {
+        name: "one-client-lan",
+        clients: 1,
+        steps: 80,
+        faults: Faults::lan,
+        link_flaps: false,
+        restarts: false,
+        deletes_mid_upload: false,
+        settle_budget: Some(Duration::from_secs(4)),
+        syscall_budget: Duration::from_secs(2),
+        drain_budget: Duration::from_secs(20),
+    };
+
+    static ONE_CLIENT_DELETES: Profile = Profile {
+        name: "one-client-deletes",
+        clients: 1,
+        steps: 30,
+        faults: Faults::lan,
+        link_flaps: false,
+        restarts: false,
+        deletes_mid_upload: true,
+        settle_budget: Some(Duration::from_secs(4)),
+        syscall_budget: Duration::from_secs(2),
+        drain_budget: Duration::from_secs(20),
+    };
+
+    static ONE_CLIENT_ECHOES: Profile = Profile {
+        name: "one-client-echoes",
+        clients: 1,
+        steps: 60,
+        faults: Faults::echoes,
+        link_flaps: false,
+        restarts: false,
+        deletes_mid_upload: false,
+        settle_budget: Some(Duration::from_secs(6)),
+        syscall_budget: Duration::from_secs(2),
+        drain_budget: Duration::from_secs(20),
+    };
+
+    static ONE_CLIENT_FLAKY: Profile = Profile {
+        name: "one-client-flaky",
+        clients: 1,
+        steps: 80,
+        faults: Faults::wifi,
+        link_flaps: true,
+        restarts: true,
+        deletes_mid_upload: false,
+        settle_budget: None,
+        syscall_budget: Duration::from_secs(10),
+        drain_budget: Duration::from_secs(120),
+    };
+
+    /// Wi-Fi's latency, lag and lost replies without the outages: the queue
+    /// has to drain within a settle, not merely by the end.
+    static ONE_CLIENT_WIFI: Profile = Profile {
+        name: "one-client-wifi",
+        clients: 1,
+        steps: 80,
+        faults: Faults::wifi,
+        link_flaps: false,
+        restarts: false,
+        deletes_mid_upload: false,
+        settle_budget: Some(Duration::from_secs(30)),
+        syscall_budget: Duration::from_secs(10),
+        drain_budget: Duration::from_secs(120),
+    };
+
+    static THREE_CLIENTS: Profile = Profile {
+        name: "three-clients",
+        clients: 3,
+        steps: 90,
+        faults: Faults::lan,
+        link_flaps: true,
+        restarts: true,
+        deletes_mid_upload: false,
+        settle_budget: Some(Duration::from_secs(4)),
+        syscall_budget: Duration::from_secs(2),
+        drain_budget: Duration::from_secs(60),
+    };
+
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse --lib sim::run -- --ignored`"]
+    fn one_client_on_a_good_link() {
+        run_seeds(&ONE_CLIENT_LAN, 12);
+    }
+
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse --lib sim::run -- --ignored`"]
+    fn one_client_deleting_files_as_they_upload() {
+        run_seeds(&ONE_CLIENT_DELETES, 3);
+    }
+
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse --lib sim::run -- --ignored`"]
+    fn one_client_with_stale_hashes_and_reordered_echoes() {
+        run_seeds(&ONE_CLIENT_ECHOES, 6);
+    }
+
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse --lib sim::run -- --ignored`"]
+    fn one_client_on_a_flaky_link() {
+        run_seeds(&ONE_CLIENT_FLAKY, 4);
+    }
+
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse --lib sim::run -- --ignored`"]
+    fn one_client_on_a_slow_link() {
+        run_seeds(&ONE_CLIENT_WIFI, 4);
+    }
+
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse --lib sim::run -- --ignored`"]
+    fn three_clients_one_writer_each() {
+        run_seeds(&THREE_CLIENTS, 3);
+    }
+
+    #[test]
+    fn conflict_copies_are_recognised_by_name() {
+        assert!(is_conflict_copy("c0/x/a (sync-conflict 1790000000).txt"));
+        assert!(is_conflict_copy("recovered-XrPUSW5W"));
+        assert!(!is_conflict_copy("c0/x/a.txt"));
+    }
+
+    #[test]
+    fn a_write_kept_because_its_file_is_gone_is_recognised() {
+        let kept = "queued write conflicts; keeping a conflict copy uid=simvol~L10 \
+                    name=\"f.txt\" reason=\"the file was trashed remotely\"";
+        assert!(is_own_delete_kept(kept));
+        assert!(is_own_delete_kept(
+            &kept.replace("was trashed", "no longer exists")
+        ));
+        assert!(!is_own_delete_kept(
+            &kept.replace("the file was trashed remotely", "revision changed")
+        ));
+    }
+}

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

@@ -0,0 +1,322 @@
+//! Turns a call through a mount that never returns into a failed seed.
+//!
+//! A deadlock in a daemon leaves the run's own thread blocked in the kernel,
+//! where no budget check is reached, and a CI job then waits for its timeout.
+//! The watchdog runs beside the run. When what it was armed for outlives its
+//! limit, it aborts the FUSE connections of the run's mounts, so the blocked
+//! call fails and the run reports the hang, and writes where every thread was
+//! to `stacks.txt`.
+//!
+//! The stacks are taken in the process: no tracer can stop a thread that
+//! waits on a FUSE request, so `gdb` and `eu-stack` wait as long as the hang.
+//! Each thread is sent [`stack_signal`] and captures its own backtrace in the
+//! handler. A thread in the kernel takes the signal only once it leaves, so
+//! the mounts are aborted after the others have answered, and its backtrace
+//! is the call it was blocked in. Its kernel wait channel is recorded first.
+
+use std::collections::BTreeMap;
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+use parking_lot::Mutex;
+
+use super::daemon::wait_until;
+
+/// How long the threads that are not blocked in the kernel have to answer,
+/// and the blocked ones once the mounts are aborted.
+const ANSWER: Duration = Duration::from_secs(5);
+
+pub(crate) struct Watchdog {
+    shared: Arc<Shared>,
+    thread: Option<JoinHandle<()>>,
+}
+
+struct Shared {
+    /// The run's directory: its mounts are below it, and the stacks go in it.
+    dir: PathBuf,
+    armed: Mutex<Option<Armed>>,
+    /// What hung, once something has.
+    fired: Mutex<Option<Hung>>,
+    stop: AtomicBool,
+}
+
+struct Armed {
+    what: String,
+    limit: Duration,
+    since: Instant,
+}
+
+/// What hung, and where every thread was then.
+#[derive(Clone, Debug, PartialEq)]
+pub(crate) struct Hung {
+    pub(crate) what: String,
+    pub(crate) stacks: String,
+}
+
+/// Disarms the watchdog when dropped.
+pub(crate) struct Watching(Arc<Shared>);
+
+impl Watchdog {
+    pub(crate) fn new(dir: &Path) -> Self {
+        let shared = Arc::new(Shared {
+            dir: dir.to_path_buf(),
+            armed: Mutex::new(None),
+            fired: Mutex::new(None),
+            stop: AtomicBool::new(false),
+        });
+        let thread = {
+            let shared = shared.clone();
+            std::thread::Builder::new()
+                .name("sim-watchdog".into())
+                .spawn(move || watch(&shared))
+                .expect("spawn the simulation watchdog")
+        };
+        Self {
+            shared,
+            thread: Some(thread),
+        }
+    }
+
+    /// Watch `what` until the guard is dropped, and abort the mounts if it is
+    /// still going after `limit`.
+    pub(crate) fn arm(&self, limit: Duration, what: impl Into<String>) -> Watching {
+        *self.shared.armed.lock() = Some(Armed {
+            what: what.into(),
+            limit,
+            since: Instant::now(),
+        });
+        Watching(self.shared.clone())
+    }
+
+    /// What hung, if something did. Call [`Watchdog::stop`] first, or the
+    /// stacks may still be on their way.
+    pub(crate) fn fired(&self) -> Option<Hung> {
+        self.shared.fired.lock().clone()
+    }
+
+    /// Stop watching, once the stacks of a hang that was caught are taken.
+    pub(crate) fn stop(&mut self) {
+        self.shared.stop.store(true, Ordering::Relaxed);
+        if let Some(thread) = self.thread.take() {
+            let _ = thread.join();
+        }
+    }
+}
+
+impl Drop for Watching {
+    fn drop(&mut self) {
+        *self.0.armed.lock() = None;
+    }
+}
+
+impl Drop for Watchdog {
+    fn drop(&mut self) {
+        self.stop();
+    }
+}
+
+fn watch(shared: &Shared) {
+    while !shared.stop.load(Ordering::Relaxed) {
+        std::thread::sleep(Duration::from_millis(200));
+        let hung = shared
+            .armed
+            .lock()
+            .as_ref()
+            .filter(|armed| armed.since.elapsed() > armed.limit)
+            .map(|armed| format!("{} has not returned after {:?}", armed.what, armed.limit));
+        let Some(hung) = hung else { continue };
+        *shared.armed.lock() = None;
+        let path = shared.dir.join("stacks.txt");
+        // Before anything is let go: the run reports the hang, not whatever
+        // the aborted call answers.
+        *shared.fired.lock() = Some(Hung {
+            what: format!("{hung}; the stacks are in {}", path.display()),
+            stacks: String::new(),
+        });
+        let stacks = take_stacks(|| abort_mounts_below(&shared.dir));
+        let what = match std::fs::write(&path, &stacks) {
+            Ok(()) => format!("{hung}; the stacks are in {}", path.display()),
+            Err(error) => format!("{hung}; the stacks could not be kept: {error}"),
+        };
+        *shared.fired.lock() = Some(Hung { what, stacks });
+    }
+}
+
+/// One thread of this process as the kernel sees it.
+struct Task {
+    tid: i32,
+    name: String,
+    /// `D` while it waits in the kernel uninterruptibly.
+    state: String,
+    wchan: String,
+}
+
+/// Where every other thread of this process is, with `release` called once
+/// those not blocked in the kernel have answered.
+fn take_stacks(release: impl FnOnce()) -> String {
+    let own = gettid();
+    let tasks = tasks();
+    STACKS.lock().clear();
+    install_stack_handler();
+    for task in &tasks {
+        if task.tid != own {
+            // SAFETY: tgkill only sends a signal, whose handler is installed.
+            unsafe {
+                libc::syscall(
+                    libc::SYS_tgkill,
+                    std::process::id() as i32,
+                    task.tid,
+                    stack_signal(),
+                )
+            };
+        }
+    }
+    let answered = |blocked: bool| {
+        let stacks = STACKS.lock();
+        tasks
+            .iter()
+            .filter(|task| task.tid != own && (blocked || task.state != "D"))
+            .all(|task| stacks.contains_key(&task.tid))
+    };
+    wait_until(ANSWER, || answered(false));
+    release();
+    wait_until(ANSWER, || answered(true));
+    let stacks = std::mem::take(&mut *STACKS.lock());
+    let mut out = String::new();
+    for task in tasks.iter().filter(|task| task.tid != own) {
+        out.push_str(&format!(
+            "thread {} {:?}, state {}, waiting in {}\n",
+            task.tid, task.name, task.state, task.wchan
+        ));
+        match stacks.get(&task.tid) {
+            Some(stack) => out.push_str(&format!("{stack}\n")),
+            None => out.push_str("  (no answer)\n\n"),
+        }
+    }
+    out
+}
+
+fn tasks() -> Vec<Task> {
+    let Ok(entries) = std::fs::read_dir("/proc/self/task") else {
+        return Vec::new();
+    };
+    let read = |dir: &Path, file: &str| {
+        std::fs::read_to_string(dir.join(file))
+            .unwrap_or_default()
+            .trim()
+            .to_owned()
+    };
+    entries
+        .flatten()
+        .filter_map(|entry| {
+            let tid = entry.file_name().to_str()?.parse().ok()?;
+            let dir = entry.path();
+            // The state follows the name in parentheses, which may hold spaces.
+            let stat = read(&dir, "stat");
+            let state = stat.rsplit_once(") ")?.1.split(' ').next()?.to_owned();
+            Some(Task {
+                tid,
+                name: read(&dir, "comm"),
+                state,
+                wchan: read(&dir, "wchan"),
+            })
+        })
+        .collect()
+}
+
+/// The backtraces the threads captured, by thread id.
+static STACKS: Mutex<BTreeMap<i32, std::backtrace::Backtrace>> = Mutex::new(BTreeMap::new());
+
+/// The signal that asks a thread for its stack: one of the real-time signals
+/// that nothing in the daemon uses.
+fn stack_signal() -> i32 {
+    libc::SIGRTMIN() + 7
+}
+
+fn install_stack_handler() {
+    static INSTALLED: std::sync::Once = std::sync::Once::new();
+    extern "C" fn handler(_: i32) {
+        // Not async-signal-safe: the capture allocates. The process is being
+        // taken down for a hang anyway, and a thread interrupted inside the
+        // allocator only fails to answer.
+        let stack = std::backtrace::Backtrace::force_capture();
+        STACKS.lock().insert(gettid(), stack);
+    }
+    INSTALLED.call_once(|| {
+        // SAFETY: a zeroed sigaction with a handler and SA_RESTART is valid,
+        // and the handler only touches `STACKS`.
+        unsafe {
+            let mut action: libc::sigaction = std::mem::zeroed();
+            action.sa_sigaction = handler as extern "C" fn(i32) as usize;
+            action.sa_flags = libc::SA_RESTART;
+            libc::sigemptyset(&mut action.sa_mask);
+            libc::sigaction(stack_signal(), &action, std::ptr::null_mut());
+        }
+    });
+}
+
+fn gettid() -> i32 {
+    // SAFETY: gettid has no arguments and cannot fail.
+    unsafe { libc::gettid() }
+}
+
+/// Abort the FUSE connection of every mount below `dir`. Its connection is
+/// named by the mount's device minor, and the mount's owner may abort it.
+fn abort_mounts_below(dir: &Path) {
+    let Ok(mountinfo) = std::fs::read_to_string("/proc/self/mountinfo") else {
+        return;
+    };
+    for line in mountinfo.lines() {
+        let fields: Vec<&str> = line.split(' ').collect();
+        let (Some(device), Some(mountpoint)) = (fields.get(2), fields.get(4)) else {
+            continue;
+        };
+        if !Path::new(mountpoint).starts_with(dir) {
+            continue;
+        }
+        if let Some((_, minor)) = device.split_once(':') {
+            let _ = std::fs::write(format!("/sys/fs/fuse/connections/{minor}/abort"), "1");
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::sim::daemon::scratch;
+
+    #[test]
+    #[ignore = "signals every thread of the test process: run with `cargo test -p pdfs-fuse sim:: -- --ignored`"]
+    fn a_call_past_its_limit_is_reported_with_the_stacks() {
+        let dir = scratch("watchdog");
+        let mut watchdog = Watchdog::new(&dir);
+        {
+            let _watching = watchdog.arm(Duration::from_millis(100), "a nap");
+            std::thread::sleep(Duration::from_secs(1));
+        }
+        watchdog.stop();
+        let hung = watchdog.fired().expect("the watchdog fired");
+        assert!(
+            hung.what.starts_with("a nap has not returned after"),
+            "{hung:?}"
+        );
+        assert!(hung.stacks.contains("a_call_past_its_limit"), "{hung:?}");
+        let kept = std::fs::read_to_string(dir.join("stacks.txt")).unwrap_or_default();
+        assert_eq!(kept, hung.stacks);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn a_call_within_its_limit_is_not() {
+        let dir = scratch("watchdog-quiet");
+        let watchdog = Watchdog::new(&dir);
+        drop(watchdog.arm(Duration::from_millis(100), "a quick call"));
+        std::thread::sleep(Duration::from_millis(500));
+        assert_eq!(watchdog.fired(), None);
+        drop(watchdog);
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}

crates/pdfs-fuse/src/state.rs

@@ -129,6 +129,44 @@ pub(crate) struct WriteHandle {
 }
 
 impl WriteHandle {
+    /// A handle on a file `create` just made: an empty base, so everything
+    /// written through it is authored.
+    ///
+    /// The base is `node` as it actually exists — the empty file the server just
+    /// minted, or a queued create's placeholder — never the local clock or a
+    /// blank. `queue_revision` turns it into `StagedWrite::based_on` and the
+    /// drain compares the remote against that. A `now_secs()` mtime differs from
+    /// the server's stamp by the create round-trip. A missing revision id drops
+    /// the check to `(mtime, size)`, and moving or renaming the file advances
+    /// its mtime on the server. Either way the first write to a brand-new file
+    /// lands as a conflict copy of its own empty create (`docs/BUGS.md` B113).
+    pub(crate) fn created(ino: u64, node: &Node, file: File, path: PathBuf) -> Self {
+        Self {
+            ino,
+            uid: node.uid.clone(),
+            file: Arc::new(file),
+            path,
+            written: Intervals::default(),
+            len: 0,
+            base_size: 0,
+            base_mtime: node.modification_time,
+            base_revision_id: crate::node_revision_id(node),
+            dirty: false,
+            open_count: 0,
+        }
+    }
+
+    /// Write over `node` from now on: a revision this daemon has just put on the
+    /// server under the handle, by sealing an upload or by landing the queued
+    /// create the handle was opened on. The base the handle opened over is gone,
+    /// and keeping it would make the drain read our own revision as another
+    /// device's edit.
+    pub(crate) fn rebase_onto(&mut self, node: &Node) {
+        self.base_mtime = node.modification_time;
+        self.base_size = crate::node_size(node);
+        self.base_revision_id = crate::node_revision_id(node);
+    }
+
     /// Account for `[offset, end)` having been written through this handle.
     ///
     /// A write past the end leaves a hole that reads as zeros, exactly like a
@@ -145,7 +183,7 @@ impl WriteHandle {
     }
 }
 
-/// A released write whose upload has not happened yet (offline.md Phase 3).
+/// A released write whose upload has not happened yet.
 ///
 /// The bytes live in the content cache's staging dir and the intent lives in the
 /// `pending_op` table; this pairs them in memory so a read can be served without
@@ -163,8 +201,29 @@ pub(crate) struct PendingRevision {
 /// time so this module stays free of `fuser`.
 pub(crate) type DirListing = Vec<(u64, bool, String)>;
 
+/// Where [`State::next_ino`] starts: far above any local id a database hands
+/// out, so a fallback inode never names a node that has a row.
+pub(crate) const FALLBACK_INO: u64 = 1 << 48;
+
+/// The inode of the node with local id `lid` ([`Db::lids_for`]). One above the
+/// lid, so no node takes [`crate::ROOT_INO`], which each session uses for its
+/// own root. The same in every mount and after a restart.
+pub(crate) fn lid_ino(lid: i64) -> u64 {
+    lid.unsigned_abs() + crate::ROOT_INO
+}
+
+/// 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> {
+    (ino > crate::ROOT_INO && ino < FALLBACK_INO).then(|| (ino - crate::ROOT_INO) as i64)
+}
+
 /// Mutable inode bookkeeping, guarded by a mutex because fuser drives the
 /// `Filesystem` trait through `&self`.
+///
+/// One tree for every mount of the daemon. Each FUSE session sees it from its
+/// own root ([`State::roots`]) and calls that root inode 1; `ProtonFs`
+/// translates at the kernel boundary.
 pub(crate) struct State {
     /// inode -> node metadata.
     pub(crate) entries: HashMap<u64, Entry>,
@@ -173,6 +232,12 @@ pub(crate) struct State {
     /// Cached directory listings: parent inode -> child inodes. Presence of a
     /// key means the directory has been enumerated.
     pub(crate) children: HashMap<u64, Vec<u64>>,
+    /// The inodes some session has been rooted at ([`State::install_root`]).
+    /// A root is its own parent. Kept after its session unmounts: the node is
+    /// still one of ours.
+    pub(crate) roots: HashSet<u64>,
+    /// The next inode for a node the database could not give a local id, from
+    /// a range lids never reach ([`FALLBACK_INO`]).
     pub(crate) next_ino: u64,
     /// Shared write state keyed by inode. Concurrent writers share the scratch file.
     pub(crate) active_writes: HashMap<u64, WriteHandle>,
@@ -188,13 +253,13 @@ pub(crate) struct State {
     /// two pages shifted every later entry, and the caller silently skipped or
     /// repeated whatever crossed the page boundary. Each entry is
     /// `(ino, is_dir, name)` — the kernel type is mapped at reply time so this
-    /// module stays free of `fuser` (bugs.md B43).
+    /// module stays free of `fuser` (`docs/BUGS.md` B43).
     pub(crate) dir_snapshots: HashMap<u64, Arc<DirListing>>,
     /// Resident inode attributes whose effective access changed during an
     /// intern/root refresh. Core drains this set and notifies the matching
     /// kernel only after releasing the State lock.
     pub(crate) access_changes: HashSet<u64>,
-    /// Persisted shared-root authority, loaded once per inode space and updated
+    /// Persisted shared-root authority, loaded once and updated
     /// on every explicit role/tombstone change. Descendant inheritance reads
     /// this map instead of issuing one SQLite query per interned inode.
     pub(crate) share_access: HashMap<NodeUid, Access>,
@@ -262,15 +327,6 @@ pub(crate) struct StateGuard<'a> {
     db: &'a Arc<Db>,
 }
 
-/// Take a mount's inode lock through a [`StateGuard`], for the loops that walk
-/// every live mount rather than this `Core`'s own.
-pub(crate) fn lock_state<'a>(
-    state: &'a parking_lot::Mutex<State>,
-    db: &'a Arc<Db>,
-) -> StateGuard<'a> {
-    StateGuard::new(state.lock(), db)
-}
-
 impl<'a> StateGuard<'a> {
     pub(crate) fn new(guard: parking_lot::MutexGuard<'a, State>, db: &'a Arc<Db>) -> Self {
         Self {
@@ -311,9 +367,6 @@ impl Drop for StateGuard<'_> {
 impl State {
     /// A fresh, empty inode space over `db`.
     ///
-    /// `next_ino` differs by caller: a real mount hands out [`crate::ROOT_INO`]
-    /// to its root and starts allocating above it, while a bare state under test
-    /// has no root and starts at 1.
     /// Apply the write-throughs this state owes SQLite, here and now.
     ///
     /// Production code never calls this: [`StateGuard`] releases the inode lock
@@ -340,12 +393,15 @@ impl State {
         self.db.clone()
     }
 
-    pub(crate) fn new(db: Arc<Db>, share_access: HashMap<NodeUid, Access>, next_ino: u64) -> Self {
+    /// A fresh, empty tree over `db`. A node's inode comes from its local id
+    /// ([`lid_ino`]).
+    pub(crate) fn new(db: Arc<Db>, share_access: HashMap<NodeUid, Access>) -> Self {
         Self {
             entries: HashMap::new(),
             by_uid: HashMap::new(),
             children: HashMap::new(),
-            next_ino,
+            roots: HashSet::new(),
+            next_ino: FALLBACK_INO,
             active_writes: HashMap::new(),
             handles: HashMap::new(),
             next_fh: 1,
@@ -356,18 +412,55 @@ impl State {
             outbox: Vec::new(),
         }
     }
-    /// Whether `uid` names an owned node currently reachable from this mount's
+    /// Make `root` the root of a session and return its inode, which comes
-    /// root. Resident entries can outlive their dentries for open-handle and
+    /// from its local id like any other node's.
-    /// access-revocation semantics, so `by_uid` membership alone is not proof
+    ///
-    /// that a control-socket operation may address the node.
+    /// The root is always owned. It must never be classified as a shared root,
-    pub(crate) fn owns_visible_uid(&self, uid: &NodeUid) -> bool {
+    /// even when the API returns membership data (which happens when the owner
-        let Some(root) = self.entries.get(&crate::ROOT_INO) else {
+    /// shares the folder with someone else), so a stale share row a downgrade
-            return false;
+    /// may have left for it is dropped. A node already in the tree keeps its
-        };
+    /// inode and its lookups, and stops naming a parent: a session's `..` at
-        if uid.volume_id != root.uid.volume_id {
+    /// its root is the root.
-            return false;
+    pub(crate) fn install_root(&mut self, root: Node) -> u64 {
+        if let Err(e) = self.db.upsert_node(&root) {
+            warn!(uid = %root.uid, error = %e, "db upsert root failed");
         }
+        self.share_access.remove(&root.uid);
+        let _ = self.db.delete_share_access(&root.uid);
+        let ino = match self.by_uid.get(&root.uid) {
+            Some(&ino) => ino,
+            None => self.new_inos(&[&root])[&root.uid],
+        };
+        if let Some(old) = self.entries.get(&ino).map(|e| e.parent)
+            && old != ino
+            && let Some(kids) = self.children.get_mut(&old)
+        {
+            kids.retain(|&k| k != ino);
+        }
+        self.by_uid.insert(root.uid.clone(), ino);
+        let lookup_count = self.entries.get(&ino).map_or(1, |e| e.lookup_count.max(1));
+        self.entries.insert(
+            ino,
+            Entry {
+                uid: root.uid.clone(),
+                parent: ino,
+                node: root,
+                access: Access::Owner,
+                lookup_count,
+                open_count: 0,
+                unlinked: false,
+            },
+        );
+        self.roots.insert(ino);
+        ino
+    }
 
+    /// Whether `uid` names an owned node currently reachable from one of
+    /// `roots`, the roots of the sessions that are mounted. Resident entries
+    /// can outlive their dentries for open-handle and access-revocation
+    /// semantics, so `by_uid` membership alone is not proof that a
+    /// control-socket operation may address the node.
+    pub(crate) fn owns_visible_uid(&self, uid: &NodeUid, roots: &[u64]) -> bool {
         let Some(&target) = self.by_uid.get(uid) else {
             return false;
         };
@@ -380,7 +473,9 @@ impl State {
             let Some(entry) = self.entries.get(&current) else {
                 return false;
             };
-            if entry.uid.volume_id != root.uid.volume_id
+            // The node's root scopes it to its own volume, excluding foreign
+            // shared-with-me residents from uid-addressed sharing.
+            if entry.uid.volume_id != uid.volume_id
                 || entry.unlinked
                 || entry.node.trashed
                 || entry.uid != entry.node.uid
@@ -388,7 +483,7 @@ impl State {
             {
                 return false;
             }
-            if current == crate::ROOT_INO {
+            if roots.contains(&current) {
                 return true;
             }
 
@@ -430,15 +525,17 @@ impl State {
         self.access_changes.drain().collect()
     }
 
-    /// Whether `uid` lives on the volume this mount is rooted in.
+    /// Whether `uid` lives on a volume some mount is rooted in.
     ///
     /// Used to decide how a node with no resolvable parent is classified:
     /// our own volume fails open (it is owned content), a foreign volume
     /// fails closed (it can only be there because of a share).
     pub(crate) fn is_own_volume(&self, uid: &NodeUid) -> bool {
-        self.entries
+        self.roots.iter().any(|ino| {
-            .get(&crate::ROOT_INO)
+            self.entries
-            .is_some_and(|root| root.uid.volume_id == uid.volume_id)
+                .get(ino)
+                .is_some_and(|root| root.uid.volume_id == uid.volume_id)
+        })
     }
 
     fn stored_share_access(&self, uid: &NodeUid) -> Option<Access> {
@@ -787,11 +884,59 @@ impl State {
         }
     }
 
-    pub(crate) fn intern(&mut self, parent: u64, node: Node) -> u64 {
+    /// Write `node` through as it is, in order with the tree's other changes.
+    pub(crate) fn write_through(&mut self, node: Node) {
+        self.outbox.push(DbWrite::Upsert(vec![node]));
+    }
+
+    pub(crate) fn intern(&mut self, parent: u64, mut node: Node) -> u64 {
+        self.keep_revision_mtime(&mut node);
         self.outbox.push(DbWrite::Upsert(vec![node.clone()]));
         self.intern_mem(parent, node)
     }
 
+    /// Keep what is already known of a file whose content has not changed.
+    ///
+    /// Drive stamps a link's `ModifyTime` on a rename or a move as well, while
+    /// POSIX leaves a file's mtime alone there. The content cache is keyed by
+    /// it, too: taking the new stamp made the cached bytes unreachable, so the
+    /// next partial write could not fill its gaps (docs/BUGS.md B123). The
+    /// active revision id says whether the content is still the same, and so
+    /// whether the size and digest a listing left out are still the ones known.
+    fn keep_revision_mtime(&self, node: &mut Node) {
+        let Some(entry) = self
+            .by_uid
+            .get(&node.uid)
+            .and_then(|ino| self.entries.get(ino))
+        else {
+            return;
+        };
+        if let (
+            NodeKind::File {
+                active_revision_id: Some(now),
+                claimed_size,
+                content_sha1,
+                ..
+            },
+            NodeKind::File {
+                active_revision_id: Some(was),
+                claimed_size: size_was,
+                content_sha1: sha1_was,
+                ..
+            },
+        ) = (&mut node.kind, &entry.node.kind)
+            && now == was
+        {
+            node.modification_time = entry.node.modification_time;
+            if claimed_size.is_none() {
+                *claimed_size = *size_was;
+            }
+            if content_sha1.is_none() {
+                content_sha1.clone_from(sha1_was);
+            }
+        }
+    }
+
     /// Allocate (or reuse) a stable inode for a node, updating the hot-cache maps
     /// only. Every caller owes the DB a write-through — see the callers below;
     /// the split exists so a batch can pay for one transaction instead of `n`.
@@ -800,7 +945,19 @@ impl State {
         self.intern_mem_with_access(parent, node, access)
     }
 
-    fn intern_mem_with_access(&mut self, parent: u64, mut node: Node, access: Access) -> u64 {
+    fn intern_mem_with_access(&mut self, parent: u64, node: Node, access: Access) -> u64 {
+        self.intern_mem_at(parent, node, access, None)
+    }
+
+    /// [`State::intern_mem_with_access`], with the inode a new entry takes when
+    /// the caller already has it ([`State::new_inos`]).
+    fn intern_mem_at(
+        &mut self,
+        parent: u64,
+        mut node: Node,
+        access: Access,
+        ino: Option<u64>,
+    ) -> u64 {
         if let Some(&ino) = self.by_uid.get(&node.uid) {
             let changed = self
                 .entries
@@ -819,8 +976,13 @@ impl State {
             }
             return ino;
         }
-        let ino = self.next_ino;
+        let ino = match ino {
-        self.next_ino += 1;
+            Some(ino) => ino,
+            None => self
+                .new_inos(&[&node])
+                .remove(&node.uid)
+                .unwrap_or_default(),
+        };
         self.by_uid.insert(node.uid.clone(), ino);
         self.entries.insert(
             ino,
@@ -837,6 +999,41 @@ impl State {
         ino
     }
 
+    /// The inodes for nodes that have no entry yet, from their local ids, in
+    /// one transaction. Should the database fail, they come from
+    /// [`State::next_ino`] instead, so the mount keeps working, with inodes
+    /// that last only this run. So do the inodes of virtual folders, which are
+    /// never stored.
+    fn new_inos(&mut self, nodes: &[&Node]) -> HashMap<NodeUid, u64> {
+        let (virtual_nodes, stored): (Vec<&Node>, Vec<&Node>) = nodes
+            .iter()
+            .partition(|node| crate::r#virtual::is_virtual_uid(&node.uid));
+        let mut inos = match self.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 for new inodes; numbering them for this run");
+                self.run_inos(&stored)
+            }
+        };
+        inos.extend(self.run_inos(&virtual_nodes));
+        inos
+    }
+
+    fn run_inos(&mut self, nodes: &[&Node]) -> HashMap<NodeUid, u64> {
+        nodes
+            .iter()
+            .map(|node| {
+                let ino = self.next_ino;
+                self.next_ino += 1;
+                (node.uid.clone(), ino)
+            })
+            .collect()
+    }
+
     /// Decrement lookup count for an inode and prune if lookup_count == 0 && open_count == 0 && unlinked.
     pub(crate) fn forget_lookup(&mut self, ino: u64, nlookup: u64) -> Option<(u64, String)> {
         if let Some(entry) = self.entries.get_mut(&ino) {
@@ -877,11 +1074,27 @@ 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, nodes: Vec<Node>) -> Vec<u64> {
+    pub(crate) fn intern_batch(&mut self, parent: u64, mut nodes: Vec<Node>) -> 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))
+            .collect();
+        let mut inos = if fresh.is_empty() {
+            HashMap::new()
+        } else {
+            self.new_inos(&fresh)
+        };
         nodes
             .into_iter()
-            .map(|node| self.intern_mem(parent, node))
+            .map(|node| {
+                let access = self.access_for_node(parent, &node);
+                let ino = inos.remove(&node.uid);
+                self.intern_mem_at(parent, node, access, ino)
+            })
             .collect()
     }
 
@@ -985,7 +1198,7 @@ impl State {
     /// re-enumerate, which is the cheaper way to stay honest about what the
     /// server did. A queued rename cannot: re-enumerating needs the network, and
     /// the server has not been told yet in any case — so this *is* the tree's
-    /// new truth until the op drains (offline.md Phase 3b).
+    /// new truth until the op drains.
     pub(crate) fn rename_in_place(
         &mut self,
         ino: u64,
@@ -1104,7 +1317,7 @@ impl State {
     /// created offline, nothing at all), so this row is the only record that the
     /// file is as long as the caller was told it is. Without it a restart serves
     /// the stale size and the file reads as truncated — or empty — while its
-    /// bytes sit safely in staging (offline.md Phase 3).
+    /// bytes sit safely in staging.
     /// Returns the node to persist rather than queueing it in the outbox, and is
     /// the one mutation here whose write-through the caller must do itself:
     /// failure has to be reported, not logged. Dropping the row silently means
@@ -1123,6 +1336,13 @@ mod tests {
     use proton_drive_rs::ShareMembership;
     use proton_drive_rs::proton_sdk::ids::{LinkId, ShareId, ShareMembershipId, VolumeId};
 
+    #[test]
+    fn an_inode_gives_back_the_lid_it_was_made_from() {
+        assert_eq!(ino_lid(lid_ino(7)), Some(7));
+        assert_eq!(ino_lid(crate::ROOT_INO), None);
+        assert_eq!(ino_lid(FALLBACK_INO + 3), None);
+    }
+
     fn uid(link: &str) -> NodeUid {
         NodeUid::new(VolumeId::from("vol"), LinkId::from(link))
     }
@@ -1199,7 +1419,7 @@ mod tests {
         let dir = TempDir::new();
         let db = Db::open(&dir.0.join("cache.db")).unwrap();
         let share_access = db.all_share_access().unwrap();
-        let st = State::new(Arc::new(db), share_access, 1);
+        let st = State::new(Arc::new(db), share_access);
         (st, dir)
     }
 
@@ -1217,6 +1437,36 @@ mod tests {
         (st, dir, src, dst)
     }
 
+    /// A node's inode comes from its row's local id, so it is the same in
+    /// every mount, after the hot cache drops it, and after a restart.
+    #[test]
+    fn a_node_keeps_its_inode_across_mounts_evictions_and_restarts() {
+        let (mut st, _dir) = state();
+        let inos = st.intern_batch(
+            0,
+            vec![
+                node("a", "root", "a.txt", false),
+                node("b", "root", "b.txt", false),
+            ],
+        );
+        st.flush_outbox();
+        let db = st.db.clone();
+        assert_ne!(inos[0], inos[1]);
+        assert!(!inos.contains(&crate::ROOT_INO));
+
+        let mut other = State::new(db.clone(), HashMap::new());
+        assert_eq!(other.intern(0, node("b", "root", "b.txt", false)), inos[1]);
+
+        st.forget_mem(&uid("a"));
+        assert_eq!(st.intern(0, node("a", "root", "a.txt", false)), inos[0]);
+
+        let mut restarted = State::new(db, HashMap::new());
+        assert_eq!(
+            restarted.intern_batch(0, vec![node("a", "root", "a.txt", false)]),
+            [inos[0]]
+        );
+    }
+
     /// 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.
@@ -1282,7 +1532,7 @@ mod tests {
         let root = uid("root").to_string();
         let state = parking_lot::Mutex::new(st);
         {
-            let mut guard = lock_state(&state, &db);
+            let mut guard = StateGuard::new(state.lock(), &db);
             guard.intern(0, node("root", "none", "My Files", true));
             assert!(
                 db.node_by_uid(&root).unwrap().is_none(),
@@ -1525,6 +1775,7 @@ mod tests {
             })
             .collect();
         st.next_ino = crate::ROOT_INO + nodes.len() as u64;
+        st.roots.insert(crate::ROOT_INO);
         // Reverse order so entries are inserted before their parents, matching
         // the hydration path's non-topological materialization.
         for (i, node) in nodes.iter().enumerate().rev() {
@@ -1899,6 +2150,51 @@ mod tests {
         assert_eq!(st.entries[&shared].access, Access::Viewer);
     }
 
+    fn at_revision(mut node: Node, revision: &str, mtime: i64) -> Node {
+        node.modification_time = mtime;
+        if let NodeKind::File {
+            active_revision_id, ..
+        } = &mut node.kind
+        {
+            *active_revision_id = Some(revision.into());
+        }
+        node
+    }
+
+    #[test]
+    fn a_renamed_file_keeps_its_mtime_until_its_content_changes() {
+        let (mut st, _dir) = state();
+        let root = st.intern(0, node("root", "none", "My Files", true));
+        let mut file = node("file", "root", "a.txt", false);
+        if let NodeKind::File {
+            claimed_size,
+            total_size_on_storage,
+            ..
+        } = &mut file.kind
+        {
+            *claimed_size = Some(7);
+            *total_size_on_storage = 519;
+        }
+        let ino = st.intern(root, at_revision(file.clone(), "r1", 100));
+        // Drive stamps the link on a rename; the content is still r1.
+        let mut renamed = at_revision(file.clone(), "r1", 160);
+        renamed.name = "b.txt".into();
+        st.intern_batch(root, vec![renamed]);
+        assert_eq!(st.entries[&ino].node.modification_time, 100);
+        assert_eq!(st.entries[&ino].node.name, "b.txt");
+        // A listing that leaves the size out still describes revision r1.
+        let mut bare = at_revision(file.clone(), "r1", 170);
+        assert_eq!(crate::node_size(&st.entries[&ino].node), 7);
+        if let NodeKind::File { claimed_size, .. } = &mut bare.kind {
+            *claimed_size = None;
+        }
+        st.intern(root, bare);
+        assert_eq!(st.entries[&ino].node.modification_time, 100);
+        assert_eq!(crate::node_size(&st.entries[&ino].node), 7);
+        st.intern(root, at_revision(file, "r2", 200));
+        assert_eq!(st.entries[&ino].node.modification_time, 200);
+    }
+
     fn handle(len: u64, base_size: u64) -> WriteHandle {
         let path = std::env::temp_dir().join(format!("pdfs-handle-test-{}", std::process::id()));
         let file = File::create(&path).unwrap();
@@ -1918,6 +2214,27 @@ mod tests {
         }
     }
 
+    /// A file created offline is written while its queued create lands. The
+    /// placeholder had no revision, so the handle takes the empty file the
+    /// create made as its base (docs/BUGS.md B113).
+    #[test]
+    fn a_handle_on_a_placeholder_is_based_on_the_create_that_landed() {
+        let mut h = handle(0, 0);
+        assert_eq!(h.base_revision_id, None);
+        let mut landed = node("real", "root", "f.mkv", false);
+        landed.modification_time = 160;
+        if let NodeKind::File {
+            active_revision_id, ..
+        } = &mut landed.kind
+        {
+            *active_revision_id = Some("empty".into());
+        }
+        h.rebase_onto(&landed);
+        assert_eq!(h.base_mtime, 160);
+        assert_eq!(h.base_size, 0);
+        assert_eq!(h.base_revision_id.as_deref(), Some("empty"));
+    }
+
     #[test]
     fn a_listing_does_not_shrink_a_file_open_for_writing() {
         let (mut st, _dir) = state();

crates/pdfs-fuse/src/sweep.rs

@@ -68,7 +68,7 @@ impl Core {
     /// docs for the identical/divergent policy.
     pub(crate) fn run_conflict_sweep_loop(&self) {
         // Both waits are interruptible, so teardown does not have to sit out a
-        // five-minute interval to join this thread (bugs.md B44).
+        // five-minute interval to join this thread (`docs/BUGS.md` B44).
         if !self.shutdown.sleep(CONFLICT_SWEEP_WARMUP) {
             return;
         }
@@ -165,7 +165,7 @@ impl Core {
         }
         match self
             .rt
-            .block_on(self.client.trash_nodes(std::slice::from_ref(uid)))
+            .block_on(self.drive.trash_nodes(std::slice::from_ref(uid)))
             .and_then(batch::into_unit)
         {
             Ok(()) => {}
@@ -175,10 +175,9 @@ impl Core {
                 return;
             }
         }
-        // Every mount, not just the primary: a conflict copy inside a sync
+        // Leaving a conflict copy hooked up in the tree keeps a node we have
-        // folder lives in that fork's inode space, and leaving it hooked up
+        // just trashed remotely visible and readable in whichever mount shows
-        // there keeps a node we have just trashed remotely visible and
+        // it (`docs/BUGS.md` B74).
-        // readable there (`docs/BUGS.md` B74).
         self.for_each_state(|st| {
             st.forget_or_unlink(uid);
         });

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

@@ -33,7 +33,7 @@ pub(crate) enum SyncMsg {
     /// Re-read the folder set and adjust the filesystem watches (after add/remove).
     Rewatch,
     /// The daemon is tearing down: finish the current pass and end the engine
-    /// thread, so the mount can join it (bugs.md B44).
+    /// thread, so the mount can join it (`docs/BUGS.md` B44).
     Stop,
 }
 
@@ -57,9 +57,10 @@ pub(crate) fn spawn(core: Core, rx: Receiver<SyncMsg>) -> Option<std::thread::Jo
 fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
     // 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: Mutex<Vec<(PathBuf, i64)>> = Mutex::new(Vec::new());
+    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 };
@@ -67,7 +68,8 @@ fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
             if matches!(event.kind, notify::EventKind::Access(_)) {
                 return;
             }
-            let _ = tx_events.send(SyncMsg::ReconcileAll);
+            let msg = event_target(&watched_events.lock(), &event.paths);
+            let _ = tx_events.send(msg);
         }) {
             Ok(w) => w,
             Err(e) => {
@@ -256,8 +258,31 @@ fn reconcile_all(core: &Core) {
     }
 }
 
+/// 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
+/// out of date), falls back to every folder.
+pub(super) fn event_target(watched: &[(PathBuf, i64)], paths: &[PathBuf]) -> SyncMsg {
+    let mut ids = paths.iter().map(|path| {
+        watched
+            .iter()
+            .filter(|(root, _)| path.starts_with(root))
+            // The deepest root, should one mirror folder sit inside another.
+            .max_by_key(|(root, _)| root.components().count())
+            .map(|(_, id)| *id)
+    });
+    match ids.next() {
+        Some(Some(first)) if ids.all(|id| id == Some(first)) => SyncMsg::Reconcile(first),
+        _ => SyncMsg::ReconcileAll,
+    }
+}
+
 /// Bring the filesystem watches in line with the current mirror-folder set:
 /// watch newly-added folders, drop removed ones.
+///
+/// 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
+/// its event thread and waits for the answer would deadlock against it.
 fn rewatch(
     core: &Core,
     watcher: &mut notify::RecommendedWatcher,
@@ -274,7 +299,7 @@ fn rewatch(
             return;
         }
     };
-    let mut have = watched.lock();
+    let mut have = watched.lock().clone();
     // Drop watches no longer wanted.
     have.retain(|(path, _)| {
         if want.iter().any(|(p, _)| p == path) {
@@ -294,6 +319,7 @@ fn rewatch(
             Err(e) => warn!(path = %path.display(), error = %e, "sync: watch failed"),
         }
     }
+    *watched.lock() = have;
 }
 
 // ---- reconcile ------------------------------------------------------------

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

@@ -20,7 +20,7 @@ impl LocalSig {
     /// Nanoseconds decide it when both sides have them; otherwise the comparison
     /// falls back to whole seconds, which is what a baseline row written before
     /// schema 28 — or a filesystem that reports no sub-second time — can support
-    /// (bugs.md B25).
+    /// (`docs/BUGS.md` B25).
     pub(super) fn same_content(&self, other: &Self) -> bool {
         if self.size != other.size {
             return false;
@@ -98,6 +98,11 @@ pub(super) struct Outcome {
     pub(super) errors: usize,
     /// Files skipped because another process held them open for writing.
     pub(super) deferred: usize,
+    /// Paths the local scan could not read, left out of the pass. Not part of
+    /// [`is_empty`](Self::is_empty) or the summary: an unreadable folder stays
+    /// unreadable from one poll to the next, so the pass reports it once, when
+    /// the set changes, rather than on every poll.
+    pub(super) unscanned: Vec<String>,
 }
 
 impl Outcome {
@@ -161,7 +166,7 @@ pub(super) enum Pending {
     /// was there. A download can run for minutes, so the apply step revalidates
     /// against it immediately before it renames over the destination: a writer
     /// that finished an edit in the meantime must not be overwritten without a
-    /// conflict copy (bugs.md B39).
+    /// conflict copy (`docs/BUGS.md` B39).
     Download {
         rel: String,
         uid: NodeUid,
@@ -227,6 +232,10 @@ pub(super) enum PassAbort {
     Interrupted,
     /// The pass could not establish its diff (a walk or the baseline load failed).
     Failed(String),
+    /// The daemon is stopping. What the pass sent before the stop has landed or
+    /// will be cancelled with the runtime; nothing more is sent, and the next
+    /// start's pass picks up from the baseline.
+    Stopped,
 }
 
 impl From<String> for PassAbort {

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

@@ -90,6 +90,96 @@ pub(super) fn filter_baseline<'a, B>(
         .collect()
 }
 
+/// The paths a local scan left out because it could not read them: a folder
+/// it has no permission for, an entry that vanished between the listing and
+/// its `stat`, a name that is not UTF-8.
+///
+/// A left-out path is not a deleted one. A pass drops everything an entry
+/// covers from classification, exactly as it drops ignored paths, so a
+/// baseline row under an unreadable folder is neither read as a local deletion
+/// nor answered with a download into a folder the pass cannot write. Failing
+/// the whole pass instead is what B55 did, and it left one root-owned folder
+/// stopping every other file in the tree from syncing (B196).
+#[derive(Default)]
+pub(super) struct Unscanned {
+    covered: HashSet<String>,
+    /// The subset worth telling the user about, with why: an entry that only
+    /// vanished mid-scan is not, since the next pass sees it settled.
+    unreadable: Vec<String>,
+}
+
+impl Unscanned {
+    /// Leave out `rel`, which vanished while the scan looked at it.
+    pub(super) fn vanished(&mut self, rel: String) {
+        self.covered.insert(rel);
+    }
+
+    /// Leave out `rel`, which cannot be read for `reason`.
+    pub(super) fn unreadable(&mut self, rel: String, reason: &str) {
+        self.unreadable.push(format!("{rel} ({reason})"));
+        self.covered.insert(rel);
+    }
+
+    /// Whether `rel` is a left-out path or lies under one.
+    pub(super) fn covers(&self, rel: &str) -> bool {
+        if self.covered.is_empty() {
+            return false;
+        }
+        let mut at = rel;
+        loop {
+            if self.covered.contains(at) {
+                return true;
+            }
+            match at.rfind('/') {
+                Some(i) => at = &at[..i],
+                None => return false,
+            }
+        }
+    }
+
+    /// The unreadable paths with their reasons, sorted, for the activity feed.
+    pub(super) fn report(&self) -> Vec<String> {
+        let mut lines = self.unreadable.clone();
+        lines.sort_unstable();
+        lines
+    }
+}
+
+/// The baseline paths a pass can see: [`filter_baseline`], minus everything
+/// under a path the scan could not read. This is the set [`guard_local_wipe`]
+/// checks and the set a push pass reads deletions from, since a path outside
+/// it is absent from the local walk by rule or by failure, never by loss.
+pub(super) fn tracked_baseline<'a, B>(
+    baseline: &'a HashMap<String, B>,
+    rules: &IgnoreRules,
+    unscanned: &Unscanned,
+) -> HashMap<String, &'a B> {
+    let mut tracked = filter_baseline(baseline, rules);
+    tracked.retain(|rel, _| !unscanned.covers(rel));
+    tracked
+}
+
+/// The baseline paths a push pass has to trash on Drive: tracked, and gone
+/// from the local walk. Shallowest first, so a trashed folder takes its
+/// children with it.
+///
+/// Built from [`tracked_baseline`] rather than from the raw baseline. Reading
+/// it raw trashed every synced path that later became ignored, because the walk
+/// skips those, and the switch to on-demand that the push pass runs for then
+/// deleted the local copy too (B197).
+pub(super) fn local_deletions<B, L>(
+    tracked: &HashMap<String, &B>,
+    local: &HashMap<String, L>,
+) -> Vec<String> {
+    let mut missing: Vec<String> = tracked
+        .keys()
+        .filter(|rel| !local.contains_key(*rel))
+        .cloned()
+        .collect();
+    missing.sort_by_key(|p| p.matches('/').count());
+    missing
+}
+
 /// Refuse to run a pass whose local side has vanished in its entirety.
 ///
 /// When every baseline path is absent locally, the likely cause is an unavailable
@@ -218,7 +308,7 @@ pub(super) fn plan_file(
     }
 
     let local_changed = local.is_some_and(|item| {
-        // Nanoseconds where both sides have them (bugs.md B25): whole seconds
+        // Nanoseconds where both sides have them (`docs/BUGS.md` B25): whole seconds
         // could not see an edit made in the same second as the last sync that
         // left the file the same length, so it was never uploaded.
         baseline.is_none_or(|base| !LocalSig::from(item).same_content(&LocalSig::from(base)))
@@ -291,7 +381,7 @@ mod file_plan_tests {
 
     /// Whole seconds cannot see an edit made inside the same second that leaves the
     /// file the same length, so a mirror silently stopped uploading it. With a
-    /// nanosecond time on both sides it is an ordinary local change (bugs.md B25).
+    /// nanosecond time on both sides it is an ordinary local change (`docs/BUGS.md` B25).
     #[test]
     fn a_same_second_same_size_edit_is_still_a_local_change() {
         let mut base = baseline(10, 20, 30, 40);

crates/pdfs-fuse/src/systemd.rs

@@ -74,6 +74,26 @@ pub(crate) fn watchdog_ping() {
     let _ = notify("WATCHDOG=1\n");
 }
 
+/// Sleep for `duration`, pinging the watchdog on the way.
+///
+/// For the stretches where the daemon is alive but has no mount, and so no
+/// supervisor: waiting for a login, or backing off after a failed mount. The
+/// manager arms the watchdog when the process starts, so without these pings a
+/// daemon that is merely retrying is aborted after `WatchdogSec` and leaves a
+/// coredump instead of the error it was logging. Never use this while mounted:
+/// there the ping must prove the control socket answers.
+pub fn idle_sleep(duration: Duration) {
+    const CHUNK: Duration = Duration::from_secs(10);
+    let mut left = duration;
+    watchdog_ping();
+    while !left.is_zero() {
+        let step = left.min(CHUNK);
+        std::thread::sleep(step);
+        left -= step;
+        watchdog_ping();
+    }
+}
+
 /// 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

@@ -530,7 +530,7 @@ fn open_archive(
 
 /// The lowercase-hex SHA-1 of everything `reader` yields — the digest Proton's
 /// photo duplicate detection is keyed on.
-fn sha1_of(reader: &mut (dyn Read + Send)) -> CoreResult<String> {
+pub(crate) fn sha1_of(reader: &mut (dyn Read + Send)) -> CoreResult<String> {
     let mut hasher = Sha1::new();
     let mut buffer = vec![0u8; 256 * 1024];
     loop {

crates/pdfs-fuse/src/transfers.rs

@@ -46,6 +46,8 @@ struct JobEntry {
     detail: Mutex<String>,
     done: AtomicU64,
     total: AtomicU64,
+    /// Housekeeping that moves nothing; see [`JobItem::background`].
+    background: bool,
 }
 
 /// The set of transfers and jobs currently in flight. Cloned `Arc`-style across
@@ -160,12 +162,25 @@ impl TransferRegistry {
     /// that carries its progress and deregisters the job when dropped. The job
     /// starts indeterminate; give it a `total` once one is known.
     pub fn begin_job(self: &Arc<Self>, title: impl Into<String>) -> JobGuard {
+        self.register_job(title.into(), false)
+    }
+
+    /// [`TransferRegistry::begin_job`] for housekeeping the user did not ask
+    /// for and that changes nothing in their files, such as an index rebuild or
+    /// a cache check. It is reported, but front ends don't call the drive busy
+    /// over it.
+    pub fn begin_background_job(self: &Arc<Self>, title: impl Into<String>) -> JobGuard {
+        self.register_job(title.into(), true)
+    }
+
+    fn register_job(self: &Arc<Self>, title: String, background: bool) -> JobGuard {
         let id = self.next.fetch_add(1, Ordering::Relaxed);
         let entry = Arc::new(JobEntry {
-            title: title.into(),
+            title,
             detail: Mutex::new(String::new()),
             done: AtomicU64::new(0),
             total: AtomicU64::new(0),
+            background,
         });
         self.jobs.lock().insert(id, entry.clone());
         JobGuard {
@@ -191,6 +206,7 @@ impl TransferRegistry {
                     detail: e.detail.lock().clone(),
                     done: e.done.load(Ordering::Relaxed),
                     total: e.total.load(Ordering::Relaxed),
+                    background: e.background,
                 }
             })
             .collect()

crates/pdfs-fuse/src/upload.rs

@@ -73,7 +73,7 @@ async fn run_uploads(
                 .upload_thumbnails_async(t.path.clone(), t.name.clone())
                 .await;
             match core
-                .client
+                .drive
                 .upload_file_from(
                     &t.parent_uid,
                     &t.name,
@@ -238,14 +238,11 @@ impl Core {
             .map_err(|error| self.errno_error(error, "upload destination"))?;
         let new_uid = self
             .rt
-            .block_on(
+            .block_on(self.drive.create_folder(parent_uid, name, Some(now_secs())))
-                self.client
-                    .create_folder(parent_uid, name, Some(now_secs())),
-            )
             .map_err(|e| CoreError::from_api(&e, &format!("create folder {name}")))?;
         let node = self
-            .fetch_node(&new_uid)
+            .fetch_minted_node(&new_uid, name)
-            .map_err(|e| self.errno_error(e, "fetch node"))?;
+            .ok_or_else(|| minted_but_unlisted(name))?;
         let mut st = self.state();
         let ino = st.intern(pino, node);
         if let Some(kids) = st.children.get_mut(&pino)

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

@@ -1,5 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 16 16">
-  <!-- Main menu: three bars. Bundled because themes such as Papirus draw
-       open-menu-symbolic as three dots, the same as every row's "more" menu. -->
-  <path fill="#222222" d="M 2,2.5 H 14 A 1,1 0 0 1 14,4.5 H 2 A 1,1 0 0 1 2,2.5 Z M 2,7 H 14 A 1,1 0 0 1 14,9 H 2 A 1,1 0 0 1 2,7 Z M 2,11.5 H 14 A 1,1 0 0 1 14,13.5 H 2 A 1,1 0 0 1 2,11.5 Z"/>
-</svg>

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

@@ -14,7 +14,6 @@
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-details-pane-symbolic.svg</file>
     <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-menu-symbolic.svg</file>
     <file preprocess="xml-stripblanks">scalable/actions/pdfs-people-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>

crates/pdfs-gui/resources/style.css

@@ -18,7 +18,9 @@
 .sidebar-status image.warning { color: var(--warning-color); }
 .sidebar-status image.error { color: var(--error-color); }
 .sidebar-quota progressbar trough, .sidebar-quota progressbar progress { min-height: 4px; }
-.sidebar-account { padding: 4px 4px 4px 8px; }
+/* The account row is the main menu's button: a row, not a pushbutton, so
+ * the name keeps the text weight. */
+button.sidebar-account { padding: 4px 8px; font-weight: normal; }
 /* A count of what waits on a page, at the end of its sidebar row */
 .sidebar-badge {
   min-width: 10px;
@@ -46,7 +48,11 @@
 .badge-pinned { color: var(--success-color); }
 .badge-cached { color: var(--success-color); }
 .badge-cloud { color: color-mix(in srgb, currentColor 55%, transparent); }
+.badge-issue { color: var(--error-color); }
 .browser-statusbar { background-color: alpha(currentColor, 0.025); }
+/* 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; }
 .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; }

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

@@ -34,6 +34,7 @@ use pages::verify::*;
 use reload::{LoadTicket, Loader, replace_items};
 use theme::{load_resources, proton_theme_active, set_proton_theme};
 use widgets::compat::*;
+use widgets::crumb::*;
 use widgets::details::*;
 use widgets::file_list::*;
 use widgets::menu::*;
@@ -75,8 +76,8 @@ use pdfs_core::control::{
     DirEntry, ErrorKind, ImportSummary, InvitationInfo, JobItem, MappingProgress, PendingOpInfo,
     PhotoItem, PhotoKind, PhotoMonth, PlaceInfo, PublicLinkInfo, RefreshScope, Request, Response,
     RestorableFolder, RestoreItem, RevisionInfo, SearchHit, ShareEntry, ShareEntryKind, SharedItem,
-    SyncFolderInfo, SyncPhase, SyncProgress, ThumbnailBuildStatus, Topic, TransferDirection,
+    SyncFolderInfo, SyncIssue, SyncPhase, SyncProgress, ThumbnailBuildStatus, Topic,
-    TransferItem, send,
+    TransferDirection, TransferItem, send,
 };
 
 use pdfs_core::mounts::{MountAccess, MountKind, MountMode, MountSpec};
@@ -119,6 +120,9 @@ struct Ui {
     /// keyring (a DBus round-trip). Populated at startup and updated only on
     /// login / logout. `None` = signed out.
     session: RefCell<Option<auth::StoredSession>>,
+    /// 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>,
     /// 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>,
@@ -199,12 +203,20 @@ impl Ui {
 }
 
 fn main() -> glib::ExitCode {
-    tracing_subscriber::fmt()
+    let verify = std::env::args().nth(1).as_deref() == Some(VERIFY_ARG);
-        .with_env_filter(
+    let logs = tracing_subscriber::fmt().with_env_filter(
-            tracing_subscriber::EnvFilter::try_from_default_env().unwrap_or_else(|_| "info".into()),
+        tracing_subscriber::EnvFilter::try_from_default_env().unwrap_or_else(|_| "info".into()),
-        )
+    );
-        .init();
+    // The verification window's stdout carries its token back to the app.
+    if verify {
+        logs.with_writer(std::io::stderr).init();
+    } else {
+        logs.init();
+    }
     i18n::init();
+    if verify {
+        return run_verification_window();
+    }
 
     // The tray launches the app with arguments ("--page locations",
     // "--confirm-stop"), which a running instance must receive too.
@@ -300,6 +312,11 @@ fn build_window(app: &adw::Application) {
             return;
         }
     };
+    // On a fresh install the daemon has not run yet to make these, and the
+    // Takeout page keeps its staged archives in the state dir (B194).
+    if let Err(e) = dirs.ensure() {
+        tracing::warn!("cannot create the app's directories: {e}");
+    }
 
     let stack = adw::ViewStack::new();
     let (login_page, login_widgets) = build_login_page();
@@ -362,6 +379,7 @@ fn build_window(app: &adw::Application) {
         busy: Cell::new(0),
         opening: RefCell::new(HashSet::new()),
         session: RefCell::new(auth::load().ok()),
+        unlock_offered: Cell::new(false),
         mounted: RefCell::new(false),
         sidebar: sidebar_list.clone(),
         nav: split.clone(),
@@ -561,6 +579,7 @@ fn build_window(app: &adw::Application) {
                 detail: locations_widgets.card_detail.clone(),
                 pause: locations_widgets.pause.clone(),
                 paused: Cell::new(false),
+                sign_in: locations_widgets.card_sign_in.clone(),
             },
             queue: QueueState {
                 group: locations_widgets.queue_group.clone(),
@@ -813,7 +832,6 @@ fn build_sidebar(footer: &gtk4::Box) -> (adw::NavigationPage, gtk4::ListBox) {
 
     let header = adw::HeaderBar::new();
     header.set_title_widget(Some(&brand));
-    header.pack_end(&build_primary_menu());
 
     let scroll = gtk4::ScrolledWindow::builder()
         .hscrollbar_policy(gtk4::PolicyType::Never)
@@ -1136,25 +1154,7 @@ fn toast_failure(ui: &Rc<Ui>, what: &str, message: &str, kind: ErrorKind) {
     }
 }
 
-/// The sidebar's primary (hamburger) menu: the app-level entries that don't
+/// Back the main menu's entries with window actions.
-/// belong on any one page.
-fn build_primary_menu() -> gtk4::MenuButton {
-    let menu = gio::Menu::new();
-    menu.append(Some(&gettext("Preferences")), Some("win.preferences"));
-    menu.append(Some(&gettext("Keyboard Shortcuts")), Some("win.shortcuts"));
-    menu.append(
-        Some(&gettext("About Proton Drive for Linux")),
-        Some("win.about"),
-    );
-    gtk4::MenuButton::builder()
-        .icon_name("pdfs-menu-symbolic")
-        .tooltip_text(gettext("Main menu"))
-        .primary(true)
-        .menu_model(&menu)
-        .build()
-}
-
-/// Back the primary and account menus' entries with window actions.
 fn install_window_actions(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
     let preferences = gio::SimpleAction::new("preferences", None);
     let ui_prefs = ui.clone();
@@ -1206,7 +1206,7 @@ fn install_window_actions(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
         let dialog = adw::AboutDialog::builder()
             .application_name(gettext("Proton Drive for Linux"))
             .application_icon("io.narl.proton-drive-linux")
-            .version(pdfs_core::config::APP_VERSION)
+            .version(env!("CARGO_PKG_VERSION"))
             .developer_name("Nils Pukropp")
             .website("https://proton-drive.narl.io")
             .issue_url("https://github.com/narrrl/proton-drive-linux/issues")
@@ -1291,6 +1291,12 @@ fn install_launch_actions(ui: &Rc<Ui>, app: &adw::Application, window: &adw::App
         if ui_page.session.borrow().is_none() {
             return;
         }
+        // Signed in, but Proton refused the session (the tray's "Sign In
+        // Again…"): the login page, with the rest of the app still reachable.
+        if page == "login" {
+            show_login(&ui_page);
+            return;
+        }
         // Activity lives on as the Sync page's History view.
         if page == "activity" {
             ui_page.locations.views.set_visible_child_name("history");
@@ -1346,8 +1352,8 @@ fn debug_info(ui: &Rc<Ui>) -> String {
     format!(
         "App version: {}\nUser agent: {}\nlibadwaita: {}.{}.{}\nGTK: {}.{}.{}\n\
          Mountpoint: {}\nControl socket: {}\nMount service running: {}\n",
-        pdfs_core::config::APP_VERSION,
+        config.resolved_app_version(),
-        pdfs_core::config::USER_AGENT,
+        config.resolved_user_agent(),
         adw::major_version(),
         adw::minor_version(),
         adw::micro_version(),

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

@@ -341,6 +341,59 @@ fn detail_label(entry: &ActivityEntry) -> Option<String> {
             &[("name", alt)],
         ));
     }
+    if let Some((reason, copy)) = detail.split_once("; local changes uploaded as ") {
+        let args = [("name", copy)];
+        return Some(match edit_conflict(reason) {
+            // Translators: {name} is the copy the changes made on this
+            // computer were uploaded as.
+            EditConflict::Gone => gettext_f(
+                "It no longer exists on Proton Drive, so your changes were uploaded as {name}",
+                &args,
+            ),
+            // Translators: {name} is the copy the changes made on this
+            // computer were uploaded as.
+            EditConflict::Trashed => gettext_f(
+                "It was moved to the Trash on Proton Drive, so your changes were uploaded as {name}",
+                &args,
+            ),
+            // Translators: {name} is the copy the changes made on this
+            // computer were uploaded as.
+            EditConflict::Changed => gettext_f(
+                "It was changed on Proton Drive, so your changes were uploaded as {name}",
+                &args,
+            ),
+            // Translators: {name} is the copy the changes made on this
+            // computer were uploaded as.
+            EditConflict::Other => gettext_f("Your changes were uploaded as {name}", &args),
+        });
+    }
+    if let Some((reason, path)) = detail.split_once("; local changes kept at ") {
+        let path = tilde_path(path);
+        let args = [("path", path.as_str())];
+        return Some(match edit_conflict(reason) {
+            // Translators: {path} is the file on this computer that holds the
+            // changes which could not be uploaded.
+            EditConflict::Gone => gettext_f(
+                "It no longer exists on Proton Drive, so your changes were kept in {path}",
+                &args,
+            ),
+            // Translators: {path} is the file on this computer that holds the
+            // changes which could not be uploaded.
+            EditConflict::Trashed => gettext_f(
+                "It was moved to the Trash on Proton Drive, so your changes were kept in {path}",
+                &args,
+            ),
+            // Translators: {path} is the file on this computer that holds the
+            // changes which could not be uploaded.
+            EditConflict::Changed => gettext_f(
+                "It was changed on Proton Drive, so your changes were kept in {path}",
+                &args,
+            ),
+            // Translators: {path} is the file on this computer that holds the
+            // changes which could not be uploaded.
+            EditConflict::Other => gettext_f("Your changes were kept in {path}", &args),
+        });
+    }
     if let Some(base) = detail.strip_prefix("differs from ") {
         // Translators: {name} is the file the conflicting copy was made from.
         return Some(gettext_f("Differs from {name}", &[("name", base)]));
@@ -388,6 +441,26 @@ fn detail_label(entry: &ActivityEntry) -> Option<String> {
     Some(capitalize(detail))
 }
 
+/// Why a queued edit could not land on its file, from the reason the daemon
+/// gives before "; local changes uploaded as" or "; local changes kept at".
+enum EditConflict {
+    Gone,
+    Trashed,
+    Changed,
+    Other,
+}
+
+fn edit_conflict(reason: &str) -> EditConflict {
+    match reason {
+        "the file no longer exists remotely" => EditConflict::Gone,
+        "the file was trashed remotely" => EditConflict::Trashed,
+        r if r.starts_with("the remote revision changed under the queued write") => {
+            EditConflict::Changed
+        }
+        _ => EditConflict::Other,
+    }
+}
+
 /// A sync pass summary such as "2 uploaded, 1 folder(s) created", as a
 /// list of counts. `None` when a part is not one the daemon writes.
 fn sync_summary(detail: &str) -> Option<String> {
@@ -596,6 +669,38 @@ mod tests {
         assert_eq!(d.details, vec!["1 person can view"]);
     }
 
+    #[test]
+    fn an_edit_kept_as_a_copy_says_why_in_words() {
+        let d = describe(&entry(
+            ActivityKind::Upload,
+            "notes.txt",
+            "the remote revision changed under the queued write \
+             (based on revision r1, remote now at r2); \
+             local changes uploaded as notes (sync-conflict 1700000000).txt",
+            false,
+        ));
+        assert_eq!(
+            d.details,
+            vec![
+                "It was changed on Proton Drive, so your changes were uploaded as \
+                 notes (sync-conflict 1700000000).txt"
+            ]
+        );
+        let d = describe(&entry(
+            ActivityKind::Upload,
+            "notes.txt",
+            "the file was trashed remotely; local changes kept at /var/staging/7",
+            false,
+        ));
+        assert_eq!(
+            d.details,
+            vec![
+                "It was moved to the Trash on Proton Drive, so your changes were kept in \
+                 /var/staging/7"
+            ]
+        );
+    }
+
     #[test]
     fn unknown_details_show_as_written() {
         let d = describe(&entry(

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

@@ -832,8 +832,8 @@ fn show_location_column(ui: &Rc<Ui>, visible: bool) {
     }
 }
 
-/// The menu for one entry, in the order of `docs/UI_UX_PLAN.md` §6: open,
+/// The menu for one entry, in a fixed order: open, offline, sharing,
-/// offline, sharing, organising, and the destructive item last on its own.
+/// organising, and the destructive item last on its own.
 pub(crate) fn entry_context_menu(ui: &Rc<Ui>, entry: &DirEntry) -> ActionMenu {
     let mut menu = ActionMenu::new();
     let (ui_c, entry_c) = (ui.clone(), entry.clone());
@@ -1220,9 +1220,7 @@ pub(crate) fn repaint_crumb(ui: &Rc<Ui>, path: &str) {
     ));
     let mut acc = String::new();
     for (i, seg) in segments.iter().enumerate() {
-        let sep = gtk4::Label::new(Some("›"));
+        ui.browser.crumb.append(&crumb_separator());
-        sep.add_css_class("dim-label");
-        ui.browser.crumb.append(&sep);
         acc = if acc.is_empty() {
             seg.to_string()
         } else {
@@ -1237,12 +1235,7 @@ pub(crate) fn repaint_crumb(ui: &Rc<Ui>, path: &str) {
 /// flat button that navigates to `target` (clearing any active search first).
 pub(crate) fn crumb_node(ui: &Rc<Ui>, label: &str, target: &str, current: bool) -> gtk4::Widget {
     if current {
-        let l = gtk4::Label::builder()
+        return crumb_current(label);
-            .label(label)
-            .ellipsize(gtk4::pango::EllipsizeMode::Start)
-            .build();
-        l.add_css_class("heading");
-        return l.upcast();
     }
     let button = gtk4::Button::builder().label(label).build();
     button.add_css_class("flat");
@@ -2495,9 +2488,13 @@ 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). Pinned (kept offline) ranks above merely
+/// (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.
 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;
     }
@@ -2513,9 +2510,11 @@ pub(crate) fn badge_for(entry: &DirEntry) -> Option<(&'static str, &'static str)
 /// Paint `badge` to reflect the entry's sync state (see [`badge_for`]). Clears any
 /// prior colour class first, since list factories recycle cells.
 pub(crate) fn apply_badge(badge: &gtk4::Image, entry: &DirEntry) {
-    for class in ["badge-pinned", "badge-cached", "badge-cloud"] {
+    for class in ["badge-pinned", "badge-cached", "badge-cloud", "badge-issue"] {
         badge.remove_css_class(class);
     }
+    let issue = entry.issue.map(super::locations::issue_text);
+    badge.set_tooltip_text(issue.as_deref());
     match badge_for(entry) {
         Some((icon, class)) => {
             badge.set_icon_name(Some(icon));
@@ -2915,6 +2914,7 @@ pub(crate) fn repaint_search(ui: &Rc<Ui>, hits: &[SearchHit]) {
             shared_by_unverified: false,
             trashed_at: 0,
             trashed_from: None,
+            issue: None,
         })
         .collect();
     sort_entries(&mut entries, ui.browser.view.get());
@@ -2952,11 +2952,11 @@ fn listing_summary(files: usize, folders: usize, file_bytes: u64) -> String {
 #[cfg(test)]
 mod tests {
     use super::{
-        MoveTarget, hit_location, listing_summary, move_target_allowed,
+        MoveTarget, badge_for, hit_location, listing_summary, move_target_allowed,
         show_thumbnail_build_progress, sort_entries,
     };
     use pdfs_core::config::{FileSort, FilesView};
-    use pdfs_core::control::{DirEntry, ThumbnailBuildStatus};
+    use pdfs_core::control::{DirEntry, SyncIssue, ThumbnailBuildStatus};
 
     fn entry(name: &str, is_dir: bool, size: u64, modified: i64) -> DirEntry {
         DirEntry {
@@ -2974,6 +2974,7 @@ mod tests {
             shared_by_unverified: false,
             trashed_at: 0,
             trashed_from: None,
+            issue: None,
         }
     }
 
@@ -2981,6 +2982,20 @@ mod tests {
         entries.iter().map(|e| e.name.as_str()).collect()
     }
 
+    #[test]
+    fn a_sync_issue_shows_on_the_node_before_its_cache_state() {
+        let mut file = entry("a.txt", false, 1, 0);
+        file.pinned = true;
+        assert_eq!(badge_for(&file).unwrap().1, "badge-pinned");
+        file.issue = Some(SyncIssue::Quota);
+        assert_eq!(badge_for(&file).unwrap().1, "badge-issue");
+
+        let mut folder = entry("d", true, 0, 0);
+        assert_eq!(badge_for(&folder), None);
+        folder.issue = Some(SyncIssue::Missing);
+        assert_eq!(badge_for(&folder).unwrap().1, "badge-issue");
+    }
+
     #[test]
     fn a_search_hit_location_is_its_parent_folder() {
         assert_eq!(hit_location("Work/Old/a.txt"), "Work/Old");

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

@@ -439,6 +439,10 @@ fn other_computer_row(ui: &Rc<Ui>, dev: &DeviceInfo) -> adw::ActionRow {
     menu.item(&gettext("Restore to This Computer…"), move || {
         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("Move to This Computer…"), move || {
+        prompt_migrate_device(&ui_c, &uid_c, &name_c)
+    });
     menu.section();
     let (ui_c, uid_c, name_c) = (ui.clone(), uid.clone(), name.clone());
     menu.item(&gettext("Rename…"), move || {
@@ -483,9 +487,7 @@ fn repaint_device_crumb(ui: &Rc<Ui>, nav: &[(String, String)]) {
         nav.is_empty(),
     ));
     for (i, (_, name)) in nav.iter().enumerate() {
-        let sep = gtk4::Label::new(Some("›"));
+        crumb.append(&crumb_separator());
-        sep.add_css_class("dim-label");
-        crumb.append(&sep);
         crumb.append(&device_crumb_node(ui, name, i + 1, i + 1 == nav.len()));
     }
 }
@@ -494,12 +496,7 @@ fn repaint_device_crumb(ui: &Rc<Ui>, nav: &[(String, String)]) {
 /// that goes back up to `depth` levels below the device list.
 fn device_crumb_node(ui: &Rc<Ui>, label: &str, depth: usize, current: bool) -> gtk4::Widget {
     if current {
-        let l = gtk4::Label::builder()
+        return crumb_current(label);
-            .label(label)
-            .ellipsize(gtk4::pango::EllipsizeMode::Start)
-            .build();
-        l.add_css_class("heading");
-        return l.upcast();
     }
     let button = gtk4::Button::builder().label(label).build();
     button.add_css_class("flat");
@@ -1096,6 +1093,67 @@ pub(crate) fn prompt_adopt_device(ui: &Rc<Ui>, uid: &str, name: &str) {
     dialog.present(win.as_ref());
 }
 
+/// Ask before moving another computer's folders into this computer's backup,
+/// then offer them for syncing here.
+///
+/// Destructive-looking on purpose: the other computer keeps its device but
+/// loses its folders, and a copy of Proton Drive still running there would
+/// watch them vanish.
+pub(crate) fn prompt_migrate_device(ui: &Rc<Ui>, uid: &str, name: &str) {
+    let win = ui_window(ui);
+    let dialog = adw::AlertDialog::builder()
+        .heading(gettext("Move Backup to This Computer?"))
+        // Translators: {name} is the name of the other computer whose folders move to this one.
+        .body(gettext_f(
+            "The folders backed up by “{name}” move into this computer's backup in Proton Drive, and you choose where they go on this computer. “{name}” stays in your account, without those folders.\n\nStop Proton Drive on “{name}” first. Otherwise it sees its folders disappear.",
+            &[("name", name)],
+        ))
+        .build();
+    dialog.add_response("cancel", &gettext("Cancel"));
+    dialog.add_response("move", &gettext("Move Here"));
+    dialog.set_response_appearance("move", adw::ResponseAppearance::Destructive);
+    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 computer whose folders moved to this one.
+    let done = gettext_f("Moved the backup of “{name}”", &[("name", name)]);
+    dialog.connect_response(None, move |_, resp| {
+        if resp != "move" {
+            return;
+        }
+        ui.busy_begin();
+        let rx = spawn_request(
+            ui.dirs.control_socket(),
+            Request::MigrateDevice { uid: 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 move that backup");
+            match result {
+                Ok(Ok(Response::Ok { .. })) => {
+                    reload_sync_pages(&ui);
+                    toast(&ui, &done);
+                    // The folders are this computer's now, so its own restore
+                    // picker is where the user chooses their local paths.
+                    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());
+}
+
 /// Run a mutation raised from Computers or Locations and reload the page on success.
 pub(crate) fn run_devices_mutation(ui: &Rc<Ui>, req: Request, done: &str, failed: &str) {
     ui.busy_begin();

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

@@ -7,7 +7,7 @@
 //! `~/ProtonDrive` mount, plus each folder this computer backs up, whether it is
 //! a mirrored local directory or an on-demand FUSE session. The page is called
 //! *Locations* rather than *Mounts* because a mirror folder is a plain directory
-//! with no FUSE session behind it (mount-architecture.md §4).
+//! with no FUSE session behind it.
 //!
 //! The device rows drive the same control requests the Computers page used to:
 //! mode switch, sync now, remove. What is new here is that the primary mount is
@@ -46,6 +46,8 @@ pub(crate) struct SyncCard {
     pub(crate) pause: adw::SplitButton,
     /// Whether the last status said paused, so the button knows which way to go.
     pub(crate) paused: Cell<bool>,
+    /// Shown only while Proton refuses the session; opens the sign-in page.
+    pub(crate) sign_in: gtk4::Button,
 }
 
 /// What a folder row's controls are built from. The subtitle and progress bar
@@ -70,8 +72,9 @@ pub(crate) struct LocationRow {
     progress: gtk4::ProgressBar,
 }
 
-/// What a queue row shows that can change: id, attempts, next attempt, parked.
+/// What a queue row shows that can change: id, attempts, next attempt, parked,
-pub(crate) type QueueKey = (i64, i64, Option<i64>, bool);
+/// issue.
+pub(crate) type QueueKey = (i64, i64, Option<i64>, bool, Option<SyncIssue>);
 
 /// The "Waiting to Upload" list: the daemon's pending-op queue.
 pub(crate) struct QueueState {
@@ -107,6 +110,7 @@ pub(crate) struct LocationsWidgets {
     pub(crate) card_icon: gtk4::Image,
     pub(crate) card_title: gtk4::Label,
     pub(crate) card_detail: gtk4::Label,
+    pub(crate) card_sign_in: gtk4::Button,
     pub(crate) pause: adw::SplitButton,
     pub(crate) queue_group: adw::PreferencesGroup,
     pub(crate) retry_all: gtk4::Button,
@@ -133,7 +137,7 @@ 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) = build_sync_card();
+    let (card, card_icon, card_title, card_detail, card_sign_in) = build_sync_card();
     let pause = build_pause_button();
     let (queue_group, retry_all) = build_queue_group();
     let conflicts_group = adw::PreferencesGroup::builder()
@@ -252,6 +256,7 @@ pub(crate) fn build_locations_page(history: &gtk4::Widget) -> (gtk4::Widget, Loc
         card_icon,
         card_title,
         card_detail,
+        card_sign_in,
         pause,
         queue_group,
         retry_all,
@@ -289,6 +294,11 @@ pub(crate) fn wire_locations(ui: &Rc<Ui>, retry: &gtk4::Button, add_folder: &gtk
     let ui_add = ui.clone();
     add_folder.connect_clicked(move |_| prompt_add_sync_folder(&ui_add));
     wire_pause(ui);
+    let ui_sign_in = ui.clone();
+    ui.locations
+        .card
+        .sign_in
+        .connect_clicked(move |_| show_login(&ui_sign_in));
     let ui_retry = ui.clone();
     ui.locations
         .queue
@@ -378,9 +388,15 @@ pub(crate) fn paint_sync_banner(ui: &Rc<Ui>) {
     state.banner.set_revealed(away && title.is_some());
 }
 
-/// The status hero: a large state icon, the state in words, and what it
+/// The status hero: a large state icon, the state in words, what it means,
-/// means.
+/// and the way out when there is one only the user can take.
-fn build_sync_card() -> (gtk4::Box, gtk4::Image, gtk4::Label, gtk4::Label) {
+fn build_sync_card() -> (
+    gtk4::Box,
+    gtk4::Image,
+    gtk4::Label,
+    gtk4::Label,
+    gtk4::Button,
+) {
     let icon = gtk4::Image::builder()
         .icon_name("pdfs-sync-symbolic")
         .pixel_size(48)
@@ -407,9 +423,17 @@ fn build_sync_card() -> (gtk4::Box, gtk4::Image, gtk4::Label, gtk4::Label) {
     let card = gtk4::Box::new(gtk4::Orientation::Horizontal, 18);
     card.add_css_class("card");
     card.add_css_class("sync-card");
+    let sign_in = gtk4::Button::builder()
+        .label(gettext("Sign In Again"))
+        .valign(gtk4::Align::Center)
+        .visible(false)
+        .build();
+    sign_in.add_css_class("pill");
+    sign_in.add_css_class("suggested-action");
     card.append(&icon);
     card.append(&text);
-    (card, icon, title, detail)
+    card.append(&sign_in);
+    (card, icon, title, detail, sign_in)
 }
 
 /// Pause/Resume, with timed pauses in its menu.
@@ -591,7 +615,7 @@ fn repaint_queue(ui: &Rc<Ui>, items: &[PendingOpInfo]) {
     items.sort_by_key(|op| (!op.failing, op.attempts == 0, op.id));
     let key: Vec<QueueKey> = items
         .iter()
-        .map(|op| (op.id, op.attempts, op.next_attempt_at, op.parked))
+        .map(|op| (op.id, op.attempts, op.next_attempt_at, op.parked, op.issue))
         .collect();
     if *queue.painted.borrow() == key {
         return;
@@ -648,6 +672,10 @@ fn queue_row(ui: &Rc<Ui>, op: &PendingOpInfo, now: i64) -> adw::ActionRow {
         "{action} · {state}",
         &[("action", &action), ("state", &state)],
     );
+    if let Some(issue) = op.issue {
+        subtitle.push('\n');
+        subtitle.push_str(&issue_text(issue));
+    }
     if let Some(error) = &op.last_error {
         subtitle.push('\n');
         // Translators: {n} is how many attempts failed, {error} the last error message.
@@ -662,7 +690,7 @@ fn queue_row(ui: &Rc<Ui>, op: &PendingOpInfo, now: i64) -> adw::ActionRow {
         .title(glib::markup_escape_text(&op.path).as_str())
         .subtitle(glib::markup_escape_text(&subtitle).as_str())
         .title_lines(1)
-        .subtitle_lines(3)
+        .subtitle_lines(if op.issue.is_some() { 5 } else { 3 })
         .tooltip_text(&op.path)
         .build();
     let image = gtk4::Image::from_icon_name(if op.failing {
@@ -687,9 +715,157 @@ fn queue_row(ui: &Rc<Ui>, op: &PendingOpInfo, now: i64) -> adw::ActionRow {
         retry.connect_clicked(move |_| retry_queued(&ui, Some(id)));
         row.add_suffix(&retry);
     }
+    if op.failing && op.exportable {
+        let export = gtk4::Button::builder()
+            .label(gettext("Export"))
+            .tooltip_text(gettext("Save a copy of this file's content elsewhere"))
+            .valign(gtk4::Align::Center)
+            .build();
+        export.add_css_class("flat");
+        let ui = ui.clone();
+        let id = op.id;
+        let name = Path::new(&op.path)
+            .file_name()
+            .map(|name| name.to_string_lossy().into_owned())
+            .unwrap_or_default();
+        export.connect_clicked(move |_| prompt_export_queued(&ui, id, &name));
+        row.add_suffix(&export);
+    }
+    if op.failing {
+        let discard = gtk4::Button::builder()
+            .label(gettext("Discard"))
+            .tooltip_text(gettext("Undo this change here instead of sending it"))
+            .valign(gtk4::Align::Center)
+            .build();
+        discard.add_css_class("flat");
+        let ui = ui.clone();
+        let id = op.id;
+        let path = op.path.clone();
+        let exportable = op.exportable;
+        discard.connect_clicked(move |_| prompt_discard_queued(&ui, id, &path, exportable));
+        row.add_suffix(&discard);
+    }
     row
 }
 
+/// What a sync issue means and what the user can do about it. The change stays
+/// queued either way.
+pub(crate) fn issue_text(issue: SyncIssue) -> String {
+    match issue {
+        SyncIssue::Quota => gettext(
+            "Your Proton Drive storage is full. Free up space or upgrade your plan, and this change uploads on its own.",
+        ),
+        SyncIssue::Access => gettext(
+            "You can no longer change this on Proton Drive. Ask the owner for edit access, or export the file to keep your version.",
+        ),
+        SyncIssue::Missing => gettext(
+            "The folder this change belongs in is gone from Proton Drive. Export the file to keep your version.",
+        ),
+        SyncIssue::Limit => gettext(
+            "Proton Drive's limit on items in a folder or on folder depth is reached. Make room in the folder, then retry.",
+        ),
+        SyncIssue::Rejected | SyncIssue::Unknown => {
+            gettext("Proton Drive refused this change. It stays queued and is tried again.")
+        }
+    }
+}
+
+/// Ask where to save a copy of a queued file's content, then have the daemon
+/// write it there. The change itself stays queued.
+fn prompt_export_queued(ui: &Rc<Ui>, id: i64, name: &str) {
+    let window = ui_window(ui);
+    let dialog = gtk4::FileDialog::builder()
+        .title(gettext("Export File"))
+        .initial_name(name)
+        .build();
+    let ui = ui.clone();
+    dialog.save(window.as_ref(), gio::Cancellable::NONE, move |res| {
+        let Ok(file) = res else { return };
+        let Some(dest) = file.path().and_then(|p| p.to_str().map(str::to_string)) else {
+            toast_error(
+                &ui,
+                &gettext("Couldn't export the file"),
+                &gettext("That location isn't a local file."),
+            );
+            return;
+        };
+        let rx = spawn_request(
+            ui.dirs.control_socket(),
+            Request::ExportPendingOp { id, dest },
+        );
+        let ui = ui.clone();
+        glib::spawn_future_local(async move {
+            match rx.recv().await {
+                Ok(Ok(Response::Ok { .. })) => toast(&ui, &gettext("File exported")),
+                Ok(Ok(Response::Error { message, kind })) => {
+                    toast_failure(&ui, &gettext("Couldn't export the file"), &message, kind)
+                }
+                _ => toast_error(
+                    &ui,
+                    &gettext("Couldn't export the file"),
+                    &gettext("The Proton Drive service didn't respond."),
+                ),
+            }
+        });
+    });
+}
+
+/// Confirm, then have the daemon drop a queued change and undo it here.
+fn prompt_discard_queued(ui: &Rc<Ui>, id: i64, path: &str, exportable: bool) {
+    let body = if exportable {
+        // Translators: {path} is the file whose queued change would be dropped.
+        gettext_f(
+            "Your changes to {path} are undone here and never reach Proton Drive. Export the file first to keep your version.",
+            &[("path", path)],
+        )
+    } else {
+        // Translators: {path} is the file or folder whose queued change would be dropped.
+        gettext_f(
+            "The change to {path} is undone here and never reaches Proton Drive.",
+            &[("path", path)],
+        )
+    };
+    let dialog = adw::AlertDialog::builder()
+        .heading(gettext("Discard Change?"))
+        .body(body)
+        .build();
+    dialog.add_response("cancel", &gettext("Cancel"));
+    dialog.add_response("discard", &gettext("Discard"));
+    dialog.set_response_appearance("discard", adw::ResponseAppearance::Destructive);
+    dialog.set_default_response(Some("cancel"));
+    dialog.set_close_response("cancel");
+    let window = ui_window(ui);
+    let ui = ui.clone();
+    dialog.connect_response(None, move |_, resp| {
+        if resp == "discard" {
+            discard_queued(&ui, id);
+        }
+    });
+    dialog.present(window.as_ref());
+}
+
+fn discard_queued(ui: &Rc<Ui>, id: i64) {
+    let rx = spawn_request(ui.dirs.control_socket(), Request::DiscardPendingOp { id });
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        match rx.recv().await {
+            Ok(Ok(Response::Ok { .. })) => {
+                toast(&ui, &gettext("Change discarded"));
+                ui.locations.queue.painted.borrow_mut().clear();
+                refresh_queue(&ui);
+            }
+            Ok(Ok(Response::Error { message, kind })) => {
+                toast_failure(&ui, &gettext("Couldn't discard the change"), &message, kind)
+            }
+            _ => toast_error(
+                &ui,
+                &gettext("Couldn't discard the change"),
+                &gettext("The Proton Drive service didn't respond."),
+            ),
+        }
+    });
+}
+
 /// Ask the daemon to stop waiting out one op's backoff, or every failed op's.
 fn retry_queued(ui: &Rc<Ui>, id: Option<i64>) {
     let rx = spawn_request(ui.dirs.control_socket(), Request::RetryPendingOp { id });

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

@@ -1,5 +1,5 @@
 use crate::*;
-use pdfs_core::proton_sdk::api::HumanVerificationCredential;
+use pdfs_core::proton_sdk::api::{HumanVerification, HumanVerificationCredential};
 
 pub(crate) struct LoginState {
     // Login page.
@@ -128,7 +128,12 @@ pub(crate) fn wire_login(ui: &Rc<Ui>) {
 
         set_signing_in(&ui, true);
         ui.login.login_status.set_text(&gettext("Signing in…"));
-        let (rx, totp_req_rx, hv_req_rx) = spawn_login(username, password);
+        let LoginChannels {
+            result: rx,
+            totp: totp_req_rx,
+            hv: hv_req_rx,
+            mailbox: mailbox_req_rx,
+        } = spawn_login(username, password);
 
         // Surface the 2FA dialog only if the SDK actually asks for a code (i.e.
         // the account has 2FA enabled). The worker blocks until the dialog feeds
@@ -145,15 +150,40 @@ pub(crate) fn wire_login(ui: &Rc<Ui>) {
         });
 
         // Same shape for human verification: only fires when the API gates the
-        // sign-in, and the worker is blocked on the token until it does.
+        // sign-in, and the worker is blocked on the credential until it does.
         let ui_hv = ui.clone();
         glib::spawn_future_local(async move {
-            if let Ok((url, token_tx)) = hv_req_rx.recv().await {
+            if let Ok((hv, credential_tx)) = hv_req_rx.recv().await {
                 ui_hv
                     .login
                     .login_status
                     .set_text(&gettext("Complete the verification to continue…"));
-                prompt_human_verification(&ui_hv, &url, token_tx);
+                // Anything but a credential drops the sender, which the worker
+                // reads as a cancelled sign-in.
+                match verify_human(hv.verification_url()).await {
+                    Verification::Solved(token) => {
+                        let _ = credential_tx.send(HumanVerificationCredential::captcha(token));
+                    }
+                    Verification::Cancelled => {}
+                    // The web view could not start, most likely its sandbox
+                    // (B195): the user's browser can show the page instead.
+                    Verification::Failed => verify_in_browser(&ui_hv, &hv, credential_tx),
+                }
+            }
+        });
+
+        // And for the mailbox password, which only a two-password account has.
+        // The worker asks again after a wrong answer, so this loops too.
+        let ui_mailbox = ui.clone();
+        glib::spawn_future_local(async move {
+            while let Ok((attempt, answer_tx)) = mailbox_req_rx.recv().await {
+                ask_mailbox(&ui_mailbox, attempt > 0, move |answer| {
+                    // A cancelled dialog drops the sender, which the worker
+                    // reads as a cancelled login.
+                    if let Some(answer) = answer {
+                        let _ = answer_tx.send(answer);
+                    }
+                });
             }
         });
 
@@ -209,6 +239,12 @@ pub(crate) fn login_error_message(error: &pdfs_core::Error) -> String {
         pdfs_core::Error::Other(message) if message.contains("two-factor") => {
             gettext("Sign-in cancelled: no two-factor code was entered.")
         }
+        pdfs_core::Error::Other(message) if message.contains("mailbox") => {
+            gettext("Sign-in cancelled: no mailbox password was entered.")
+        }
+        pdfs_core::Error::WrongMailboxPassword => {
+            gettext("That mailbox password didn't unlock your account.")
+        }
         pdfs_core::Error::Other(message) if message.contains("verification") => gettext(
             "Sign-in cancelled: the verification wasn't completed. Sign in again to get a new one.",
         ),
@@ -220,26 +256,34 @@ pub(crate) fn login_error_message(error: &pdfs_core::Error) -> String {
     }
 }
 
+/// What the login worker asks the UI for, and how it reports back.
+pub(crate) struct LoginChannels {
+    /// The final outcome, once.
+    pub(crate) result: async_channel::Receiver<Result<(), String>>,
+    /// Fires only if the account needs a 2FA code; carries the sender for it.
+    pub(crate) totp: async_channel::Receiver<std::sync::mpsc::Sender<String>>,
+    /// Fires only if the sign-in is gated: the challenge, and the sender for the
+    /// credential the user earns by solving it.
+    pub(crate) hv: async_channel::Receiver<(
+        HumanVerification,
+        std::sync::mpsc::Sender<HumanVerificationCredential>,
+    )>,
+    /// Fires only for a two-password account: how many answers were already
+    /// wrong, and the sender for the password and the "remember" choice.
+    pub(crate) mailbox: async_channel::Receiver<(u32, std::sync::mpsc::Sender<(String, bool)>)>,
+}
+
 /// Run the async SRP + optional 2FA login on a dedicated current-thread Tokio
-/// runtime. Returns two channels: the first yields the final login result once;
+/// runtime. The returned [`LoginChannels`] carry the final result and the lazy
-/// the second fires *only if* the account needs a 2FA code, carrying a
+/// prompts. Each login closure blocks the worker on a sender the UI answers, so
-/// [`std::sync::mpsc::Sender`] the UI uses to feed the code back. The login
+/// a code is requested lazily and can't expire before the password proof.
-/// closure blocks the worker on that sender until the dialog answers, so the
+pub(crate) fn spawn_login(username: String, password: String) -> LoginChannels {
-/// code is requested lazily and can't expire before the password proof.
-#[allow(clippy::type_complexity)]
-pub(crate) fn spawn_login(
-    username: String,
-    password: String,
-) -> (
-    async_channel::Receiver<Result<(), String>>,
-    async_channel::Receiver<std::sync::mpsc::Sender<String>>,
-    async_channel::Receiver<(String, std::sync::mpsc::Sender<String>)>,
-) {
     let (tx, rx) = async_channel::bounded(1);
     // Two, not one: a CAPTCHA-gated login restarts, so a 2FA account is asked
     // for a code on each attempt and a single slot would deadlock the worker.
     let (totp_req_tx, totp_req_rx) = async_channel::bounded(2);
     let (hv_req_tx, hv_req_rx) = async_channel::bounded(1);
+    let (mailbox_req_tx, mailbox_req_rx) = async_channel::bounded(1);
     std::thread::spawn(move || {
         let rt = match tokio::runtime::Builder::new_current_thread()
             .enable_all()
@@ -267,19 +311,30 @@ pub(crate) fn spawn_login(
                         .recv()
                         .map_err(|_| pdfs_core::Error::Other("two-factor entry cancelled".into()))
                 },
-                |hv| {
+                |attempt| {
-                    // Gated: hand the UI the page to show, block on the token the
+                    let (answer_tx, answer_rx) = std::sync::mpsc::channel::<(String, bool)>();
-                    // user earns by solving it.
+                    mailbox_req_tx
-                    let (token_tx, token_rx) = std::sync::mpsc::channel::<String>();
+                        .send_blocking((attempt, answer_tx))
-                    hv_req_tx
+                        .map_err(|_| pdfs_core::Error::Other("mailbox prompt closed".into()))?;
-                        .send_blocking((hv.verification_url(), token_tx))
+                    let (password, remember) = answer_rx
-                        .map_err(|_| {
-                            pdfs_core::Error::Other("verification prompt closed".into())
-                        })?;
-                    let token = token_rx
                         .recv()
-                        .map_err(|_| pdfs_core::Error::Other("verification cancelled".into()))?;
+                        .map_err(|_| pdfs_core::Error::Other("mailbox entry cancelled".into()))?;
-                    Ok(HumanVerificationCredential::captcha(token))
+                    Ok(auth::Mailbox {
+                        password: password.into(),
+                        remember,
+                    })
+                },
+                |hv| {
+                    // Gated: hand the UI the challenge, block on the credential
+                    // the user earns by solving it.
+                    let (credential_tx, credential_rx) =
+                        std::sync::mpsc::channel::<HumanVerificationCredential>();
+                    hv_req_tx.send_blocking((hv, credential_tx)).map_err(|_| {
+                        pdfs_core::Error::Other("verification prompt closed".into())
+                    })?;
+                    credential_rx
+                        .recv()
+                        .map_err(|_| pdfs_core::Error::Other("verification cancelled".into()))
                 },
             )
             .await
@@ -287,7 +342,143 @@ pub(crate) fn spawn_login(
         });
         let _ = tx.send_blocking(result);
     });
-    (rx, totp_req_rx, hv_req_rx)
+    LoginChannels {
+        result: rx,
+        totp: totp_req_rx,
+        hv: hv_req_rx,
+        mailbox: mailbox_req_rx,
+    }
+}
+
+/// Ask for the mailbox password of a two-password account.
+///
+/// `done` gets the password and the "keep unlocked" choice, or `None` when the
+/// dialog was cancelled. `retry` says the last answer was wrong. The choice
+/// defaults to off: storing the mailbox unlock in the keyring trades away what
+/// a separate mailbox password is for, so it is something to opt into.
+pub(crate) fn ask_mailbox(
+    ui: &Rc<Ui>,
+    retry: bool,
+    done: impl FnOnce(Option<(String, bool)>) + 'static,
+) {
+    let body = if retry {
+        gettext("That mailbox password didn't unlock your account. Try again.")
+    } else {
+        gettext("This account has a separate mailbox password. Enter it to unlock your files.")
+    };
+    let dialog = adw::AlertDialog::builder()
+        .heading(gettext("Mailbox Password"))
+        .body(body)
+        .build();
+
+    let group = adw::PreferencesGroup::new();
+    let entry = adw::PasswordEntryRow::builder()
+        .title(gettext("Mailbox password"))
+        .activates_default(true)
+        .build();
+    let remember = adw::SwitchRow::builder()
+        .title(gettext("Keep unlocked on this computer"))
+        .subtitle(gettext(
+            "Stores the unlock in the system keyring, so Proton Drive opens without asking after every login. Otherwise you enter the password once per session.",
+        ))
+        .build();
+    group.add(&entry);
+    group.add(&remember);
+    dialog.set_extra_child(Some(&group));
+
+    dialog.add_response("cancel", &gettext("Cancel"));
+    dialog.add_response("unlock", &gettext("Unlock"));
+    dialog.set_response_appearance("unlock", adw::ResponseAppearance::Suggested);
+    dialog.set_default_response(Some("unlock"));
+    dialog.set_close_response("cancel");
+
+    let done = RefCell::new(Some(done));
+    dialog.connect_response(None, move |_, resp| {
+        let Some(done) = done.borrow_mut().take() else {
+            return;
+        };
+        let password = entry.text().to_string();
+        if resp == "unlock" && !password.is_empty() {
+            done(Some((password, remember.is_active())));
+        } else {
+            done(None);
+        }
+    });
+
+    let parent = ui_window(ui).map(|w| w.upcast::<gtk4::Window>());
+    dialog.present(parent.as_ref());
+}
+
+/// If the signed-in account is locked, ask for its mailbox password — once per
+/// run; after a cancel, a toast keeps an Unlock button within reach.
+///
+/// The key state is a keyring and kernel-keyring read, so it runs on a worker.
+pub(crate) fn offer_unlock(ui: &Rc<Ui>) {
+    if ui.unlock_offered.get() {
+        return;
+    }
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let state = gio::spawn_blocking(|| auth::key_state().ok()).await;
+        if matches!(state, Ok(Some(auth::KeyState::Locked))) && !ui.unlock_offered.replace(true) {
+            prompt_unlock(&ui, false);
+        }
+    });
+}
+
+enum UnlockOutcome {
+    Unlocked,
+    Wrong,
+    Failed(String),
+}
+
+/// Ask for the mailbox password and unlock the account with it.
+fn prompt_unlock(ui: &Rc<Ui>, retry: bool) {
+    let ui_done = ui.clone();
+    ask_mailbox(ui, retry, move |answer| {
+        let Some((password, remember)) = answer else {
+            toast_action(
+                &ui_done,
+                &gettext("Proton Drive is locked. Enter your mailbox password to unlock it."),
+                &gettext("Unlock"),
+                |ui| prompt_unlock(ui, false),
+            );
+            return;
+        };
+        glib::spawn_future_local(async move {
+            // Verifying talks to Proton and the restart talks to systemd, so
+            // both run on a worker, never on the main loop.
+            let outcome = gio::spawn_blocking(move || {
+                let rt = match tokio::runtime::Builder::new_current_thread()
+                    .enable_all()
+                    .build()
+                {
+                    Ok(rt) => rt,
+                    Err(e) => return UnlockOutcome::Failed(e.to_string()),
+                };
+                match rt.block_on(auth::unlock(&password, remember)) {
+                    Ok(()) => {
+                        service::restart();
+                        UnlockOutcome::Unlocked
+                    }
+                    Err(pdfs_core::Error::WrongMailboxPassword) => UnlockOutcome::Wrong,
+                    Err(e) => UnlockOutcome::Failed(login_error_message(&e)),
+                }
+            })
+            .await;
+            match outcome {
+                Ok(UnlockOutcome::Unlocked) => {
+                    toast(&ui_done, &gettext("Unlocked."));
+                    refresh(&ui_done);
+                }
+                Ok(UnlockOutcome::Wrong) => prompt_unlock(&ui_done, true),
+                Ok(UnlockOutcome::Failed(message)) => {
+                    toast_error(&ui_done, &gettext("Couldn't unlock"), &message)
+                }
+                Err(_) => {}
+            }
+        });
+    });
 }
 
 /// Show the lazy two-factor dialog and feed the entered code back to the waiting
@@ -330,6 +521,63 @@ pub(crate) fn prompt_2fa(ui: &Rc<Ui>, code_tx: std::sync::mpsc::Sender<String>)
     dialog.present(parent.as_ref());
 }
 
+/// Let the user solve the challenge in their own browser, for when the
+/// verification window could not come up. The page cannot hand its token back
+/// to us, so the user says when they are done, and the retry carries the
+/// challenge token, which the solved page made good (see
+/// [`auth::browser_verified`]).
+fn verify_in_browser(
+    ui: &Rc<Ui>,
+    hv: &HumanVerification,
+    credential_tx: std::sync::mpsc::Sender<HumanVerificationCredential>,
+) {
+    let dialog = adw::AlertDialog::builder()
+        .heading(gettext("Verify in Your Browser"))
+        .body(gettext(
+            "The verification page can't be shown in the app on this system. Open it in your browser, complete it there, then come back and choose Continue.",
+        ))
+        .build();
+
+    let url = auth::browser_verification_url(hv);
+    let open = gtk4::Button::builder()
+        .label(gettext("Open Verification Page"))
+        .halign(gtk4::Align::Center)
+        .build();
+    open.add_css_class("pill");
+    dialog.set_extra_child(Some(&open));
+
+    dialog.add_response("cancel", &gettext("Cancel"));
+    dialog.add_response("continue", &gettext("Continue"));
+    dialog.set_response_appearance("continue", adw::ResponseAppearance::Suggested);
+    // Continuing before the page was even opened would only fail the retry.
+    dialog.set_response_enabled("continue", false);
+    dialog.set_default_response(Some("continue"));
+    dialog.set_close_response("cancel");
+
+    let dialog_weak = dialog.downgrade();
+    open.connect_clicked(move |_| {
+        open_uri(&url);
+        if let Some(dialog) = dialog_weak.upgrade() {
+            dialog.set_response_enabled("continue", true);
+        }
+    });
+
+    let credential = auth::browser_verified(hv);
+    let credential_tx = RefCell::new(Some(credential_tx));
+    dialog.connect_response(None, move |_, resp| {
+        // On cancel/close we take + drop `tx` without sending, so the worker's
+        // recv errors out and the login is reported as cancelled.
+        if let Some(tx) = credential_tx.borrow_mut().take()
+            && resp == "continue"
+        {
+            let _ = tx.send(credential.clone());
+        }
+    });
+
+    let parent = ui.login.login_button.root().and_downcast::<gtk4::Window>();
+    dialog.present(parent.as_ref());
+}
+
 /// Sign out, after a confirmation: disable+stop the mount service (so the
 /// daemon isn't left running without credentials), forget the stored session,
 /// and drop back to the login page.
@@ -374,6 +622,12 @@ mod tests {
         assert!(login_error_message(&hv).contains("verification wasn't completed"));
     }
 
+    #[test]
+    fn a_cancelled_mailbox_prompt_is_reported_as_such() {
+        let error = pdfs_core::Error::Other("mailbox entry cancelled".into());
+        assert!(login_error_message(&error).contains("no mailbox password"));
+    }
+
     #[test]
     fn an_unmapped_error_keeps_its_text() {
         let error = pdfs_core::Error::Other("something odd".into());

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

@@ -484,9 +484,7 @@ fn repaint_shared_crumb(ui: &Rc<Ui>, nav: &[(String, String)]) {
         nav.is_empty(),
     ));
     for (i, (_, name)) in nav.iter().enumerate() {
-        let sep = gtk4::Label::new(Some("›"));
+        crumb.append(&crumb_separator());
-        sep.add_css_class("dim-label");
-        crumb.append(&sep);
         crumb.append(&shared_crumb_node(ui, name, i + 1, i + 1 == nav.len()));
     }
 }
@@ -495,12 +493,7 @@ fn repaint_shared_crumb(ui: &Rc<Ui>, nav: &[(String, String)]) {
 /// that goes back up to `depth` folders below the top level.
 fn shared_crumb_node(ui: &Rc<Ui>, label: &str, depth: usize, current: bool) -> gtk4::Widget {
     if current {
-        let l = gtk4::Label::builder()
+        return crumb_current(label);
-            .label(label)
-            .ellipsize(gtk4::pango::EllipsizeMode::Start)
-            .build();
-        l.add_css_class("heading");
-        return l.upcast();
     }
     let button = gtk4::Button::builder().label(label).build();
     button.add_css_class("flat");

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

@@ -565,6 +565,7 @@ pub(crate) fn prompt_stop_sharing(ui: &Rc<Ui>, entries: &[DirEntry]) {
     let uids: Vec<String> = entries.iter().map(|e| e.uid.clone()).collect();
     dialog.connect_response(Some("stop"), move |_, _| {
         let done = done.clone();
+        let stopped = uids.clone();
         run_requests(
             &ui_c,
             uids.iter()
@@ -572,6 +573,7 @@ pub(crate) fn prompt_stop_sharing(ui: &Rc<Ui>, entries: &[DirEntry]) {
                 .collect(),
             gettext_noop("Couldn't stop sharing"),
             move |ui| {
+                forget_shared_by_me(ui, &stopped);
                 reload_listing(ui);
                 toast(ui, &done);
             },
@@ -580,6 +582,18 @@ pub(crate) fn prompt_stop_sharing(ui: &Rc<Ui>, entries: &[DirEntry]) {
     dialog.present(ui_window(ui).as_ref());
 }
 
+/// Take items whose sharing just stopped off the page now, rather than when
+/// the reload that confirms it comes back: that reload asks after every share
+/// in turn and takes a while with many of them.
+fn forget_shared_by_me(ui: &Rc<Ui>, uids: &[String]) {
+    let items = {
+        let mut items = ui.shared_by_me.items.borrow_mut();
+        items.retain(|item| !uids.contains(&item.uid));
+        items.clone()
+    };
+    repaint_shared_by_me(ui, &items);
+}
+
 /// Open a shared item: a folder in My Files, a file the way My Files would.
 fn open_shared_by_me(ui: &Rc<Ui>, entry: &DirEntry) {
     if entry.is_dir {
@@ -618,6 +632,7 @@ pub(crate) fn shared_item_as_entry(item: &SharedItem) -> DirEntry {
         shared_by_unverified: false,
         trashed_at: 0,
         trashed_from: None,
+        issue: None,
     }
 }
 

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

@@ -381,23 +381,34 @@ pub(crate) fn build_main_page() -> MainWidgets {
         .hexpand(true)
         .ellipsize(gtk4::pango::EllipsizeMode::Middle)
         .build();
+    // The app's one menu, on the account row the way Proton's own apps keep it:
+    // app-wide entries first, the account's last. The whole row opens it, and
+    // F10 too, as the primary menu.
+    let app_section = gio::Menu::new();
+    app_section.append(Some(&gettext("Preferences")), Some("win.preferences"));
+    app_section.append(Some(&gettext("Keyboard Shortcuts")), Some("win.shortcuts"));
+    app_section.append(
+        Some(&gettext("About Proton Drive for Linux")),
+        Some("win.about"),
+    );
+    let account_section = gio::Menu::new();
+    account_section.append(Some(&gettext("Sign Out…")), Some("win.sign-out"));
     let account_menu = gio::Menu::new();
-    account_menu.append(Some(&gettext("Preferences")), Some("win.preferences"));
+    account_menu.append_section(None, &app_section);
-    let sign_out = gio::Menu::new();
+    account_menu.append_section(None, &account_section);
-    sign_out.append(Some(&gettext("Sign Out…")), Some("win.sign-out"));
+    let row = gtk4::Box::new(gtk4::Orientation::Horizontal, 10);
-    account_menu.append_section(None, &sign_out);
+    row.append(&avatar);
-    let account_button = gtk4::MenuButton::builder()
+    row.append(&account_name);
-        .icon_name("view-more-symbolic")
+    row.append(&gtk4::Image::from_icon_name("view-more-symbolic"));
-        .tooltip_text(gettext("Account"))
+    let account = gtk4::MenuButton::builder()
+        .child(&row)
+        .tooltip_text(gettext("Main menu"))
         .menu_model(&account_menu)
-        .valign(gtk4::Align::Center)
+        .direction(gtk4::ArrowType::Up)
+        .primary(true)
         .build();
-    account_button.add_css_class("flat");
+    account.add_css_class("flat");
-    let account = gtk4::Box::new(gtk4::Orientation::Horizontal, 10);
     account.add_css_class("sidebar-account");
-    account.append(&avatar);
-    account.append(&account_name);
-    account.append(&account_button);
 
     let footer = gtk4::Box::new(gtk4::Orientation::Vertical, 10);
     footer.add_css_class("sidebar-footer");
@@ -825,6 +836,13 @@ pub(crate) fn wire_retry(ui: &Rc<Ui>) {
         .connect_clicked(move |_| restart_service_then(&ui_trash, load_trash));
 }
 
+/// Show the sign-in page while a session is still stored, because Proton has
+/// refused it. The sidebar stays, so the user can go back to cached files; a
+/// login moves on to the files as from any sign-in ([`refresh`]).
+pub(crate) fn show_login(ui: &Rc<Ui>) {
+    ui.stack.set_visible_child_name("login");
+}
+
 /// Repaint the window from the cached login identity, then ask the daemon for
 /// its status and transfers. Runs at startup, after a login and after a service
 /// restart; the daemon's event feed keeps both current in between. The identity
@@ -860,6 +878,7 @@ pub(crate) fn refresh(ui: &Rc<Ui>) {
         }
     }
 
+    offer_unlock(ui);
     refresh_status(ui);
     refresh_transfers(ui);
 }
@@ -1209,6 +1228,8 @@ pub(crate) fn paint_status(ui: &Rc<Ui>, status: Response) {
         failing_error,
         paused,
         paused_until,
+        session_expired,
+        tokens_unsaved,
         ..
     } = status
     else {
@@ -1219,7 +1240,11 @@ pub(crate) fn paint_status(ui: &Rc<Ui>, status: Response) {
     // in it: it is why a file that looks saved is not on the remote
     // yet, and offline is usually the reason it is still queued.
     let queued = i18n::pending_summary(pending_uploads, pending_changes);
-    let state = if paused {
+    let state = if session_expired {
+        SyncState::SessionExpired { queued }
+    } else if tokens_unsaved {
+        SyncState::TokensUnsaved
+    } else if paused {
         SyncState::Paused {
             until: paused_until,
             queued,
@@ -1282,6 +1307,14 @@ pub(crate) fn paint_disconnected(ui: &Rc<Ui>) {
 
 /// What the sidebar's status strip reports, most urgent first.
 pub(crate) enum SyncState {
+    /// Proton refused the session: nothing reaches it until the user signs in
+    /// again. Outranks a pause, which it makes moot.
+    SessionExpired {
+        queued: Option<String>,
+    },
+    /// The keyring refuses the session's refreshed tokens. Sync goes on, but
+    /// a reboot before the keyring takes them signs the user out.
+    TokensUnsaved,
     /// The user paused syncing; nothing goes up until it resumes. Outranks
     /// everything else, because it is the reason for everything else.
     Paused {
@@ -1316,7 +1349,29 @@ pub(crate) enum SyncState {
 fn paint_sync_status(ui: &Rc<Ui>, state: SyncState) {
     let paused = matches!(state, SyncState::Paused { .. });
     let connected = !matches!(state, SyncState::Disconnected | SyncState::NotResponding);
+    let expired = matches!(state, SyncState::SessionExpired { .. });
     let (icon, class, title, detail) = match state {
+        SyncState::SessionExpired { queued } => (
+            "dialog-password-symbolic",
+            Some("error"),
+            gettext("Session expired"),
+            Some(match queued {
+                // Translators: {queued} says what is waiting, such as "3 uploads
+                // queued".
+                Some(queued) => {
+                    gettext_f("{queued} · sign in again to sync", &[("queued", &queued)])
+                }
+                None => gettext("Sign in again to sync"),
+            }),
+        ),
+        SyncState::TokensUnsaved => (
+            "dialog-warning-symbolic",
+            Some("warning"),
+            gettext("Sign-in not saved"),
+            Some(gettext(
+                "Unlock your keyring, or the next reboot signs you out",
+            )),
+        ),
         SyncState::Paused { until, queued } => (
             "media-playback-pause-symbolic",
             Some("warning"),
@@ -1387,6 +1442,7 @@ fn paint_sync_status(ui: &Rc<Ui>, state: SyncState) {
     if let Some(class) = class {
         image.add_css_class(class);
     }
+    ui.locations.card.sign_in.set_visible(expired);
     ui.status.status_title.set_label(&title);
     ui.status.status_detail.set_visible(detail.is_some());
     ui.status

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

@@ -533,6 +533,7 @@ mod tests {
             shared_by_unverified: false,
             trashed_at,
             trashed_from: from.map(str::to_string),
+            issue: None,
         }
     }
 

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

@@ -1,4 +1,4 @@
-//! The human-verification (CAPTCHA) dialog.
+//! The human-verification (CAPTCHA) window.
 //!
 //! Proton gates logins it does not recognise — a new IP, a VPN exit — behind a
 //! CAPTCHA. The API answers the login with a challenge instead of a session, and
@@ -8,10 +8,26 @@
 //! The page is hosted in a `WebKitWebView` rather than handed to the system
 //! browser because it reports completion by posting a message to its host, not
 //! by redirecting: a browser has nowhere to post it back to.
+//!
+//! The webview runs in a child `pdfs-app` started with [`VERIFY_ARG`], not in the
+//! app itself. WebKit aborts its whole process when its sandbox cannot start, as
+//! on hardened systems that keep bubblewrap from the journal socket
+//! (`docs/BUGS.md` B195); in a child that costs the verification, not the app.
+//! The URL goes to the child on stdin, so it never shows in a process list, and
+//! the token comes back on stdout.
 
 use crate::*;
+use std::io::{BufRead, BufReader, Write as _};
+use std::process::{ExitStatus, Stdio};
 use webkit6::prelude::*;
 
+/// The argument that makes `pdfs-app` the verification window instead of the app.
+pub(crate) const VERIFY_ARG: &str = "--human-verification";
+
+/// Marks the token among whatever else lands on the child's stdout: GLib and
+/// WebKit write debug output there.
+const TOKEN_PREFIX: &str = "hv-token ";
+
 /// Bridge the verification page's `postMessage` to a handler this side can read.
 ///
 /// The page targets its embedding host (`window.parent`), which in a webview is
@@ -26,15 +42,100 @@ window.addEventListener('message', function (event) {
 });
 "#;
 
-/// Present the challenge and hand the solved token back through `token_tx`.
+/// How the verification window ended.
-///
+#[derive(Debug, PartialEq, Eq)]
-/// Closing the dialog without solving drops the sender, which the waiting login
+pub(crate) enum Verification {
-/// worker reads as a cancelled sign-in — the same contract as the 2FA prompt.
+    Solved(String),
-pub(crate) fn prompt_human_verification(
+    /// Closed without solving.
-    ui: &Rc<Ui>,
+    Cancelled,
-    url: &str,
+    /// Never came up, or died: most likely WebKit could not start its sandbox.
-    token_tx: std::sync::mpsc::Sender<String>,
+    Failed,
-) {
+}
+
+/// Show the challenge in the verification window and wait until it closes.
+pub(crate) async fn verify_human(url: String) -> Verification {
+    match gio::spawn_blocking(move || run_verification_child(&url)).await {
+        Ok(Ok(verification)) => verification,
+        Ok(Err(e)) => {
+            tracing::error!("cannot run the verification window: {e}");
+            Verification::Failed
+        }
+        Err(_) => Verification::Failed,
+    }
+}
+
+fn run_verification_child(url: &str) -> std::io::Result<Verification> {
+    let mut child = Command::new(own_exe())
+        .arg(VERIFY_ARG)
+        .stdin(Stdio::piped())
+        .stdout(Stdio::piped())
+        .spawn()?;
+    if let Some(mut stdin) = child.stdin.take() {
+        // A failed write means the child is already gone; its exit status says
+        // how. Dropping `stdin` closes it.
+        let _ = writeln!(stdin, "{url}");
+    }
+    // Stops reading at the token rather than at EOF: WebKit's helper processes
+    // inherit the pipe and may hold it open a moment after the child quits.
+    let token = child
+        .stdout
+        .take()
+        .and_then(|out| find_token(BufReader::new(out)));
+    let status = child.wait()?;
+    Ok(outcome(token, status))
+}
+
+/// This very binary, so a development build opens its own window. After an
+/// upgrade replaced the file, `current_exe` names a deleted path, and the
+/// installed `pdfs-app` is the next best.
+fn own_exe() -> PathBuf {
+    std::env::current_exe()
+        .ok()
+        .filter(|path| path.is_file())
+        .unwrap_or_else(|| PathBuf::from("pdfs-app"))
+}
+
+fn find_token(out: impl BufRead) -> Option<String> {
+    out.lines()
+        .map_while(Result::ok)
+        .find_map(|line| line.strip_prefix(TOKEN_PREFIX).map(str::to_owned))
+}
+
+/// A token wins over the exit status: the user solved the page, even if
+/// WebKit's teardown crashed after it.
+fn outcome(token: Option<String>, status: ExitStatus) -> Verification {
+    match token {
+        Some(token) => Verification::Solved(token),
+        None if status.success() => Verification::Cancelled,
+        None => {
+            tracing::error!(%status, "the verification window failed");
+            Verification::Failed
+        }
+    }
+}
+
+/// Run as the verification window: read the page's URL from stdin, show it, and
+/// print the token once the user has solved it. Closing the window exits
+/// without a token, which the app reads as a cancelled sign-in.
+pub(crate) fn run_verification_window() -> glib::ExitCode {
+    let mut url = String::new();
+    if std::io::stdin().lock().read_line(&mut url).is_err() || url.trim().is_empty() {
+        tracing::error!("{VERIFY_ARG} expects the verification URL on stdin");
+        return glib::ExitCode::FAILURE;
+    }
+    let url = url.trim().to_owned();
+
+    // Not unique: the app that started it already holds APP_ID.
+    let app = adw::Application::builder()
+        .flags(gio::ApplicationFlags::NON_UNIQUE)
+        .build();
+    app.connect_activate(move |app| build_verification_window(app, &url));
+    // GApplication would refuse VERIFY_ARG as an unknown option.
+    let argv0 = std::env::args().next().unwrap_or_default();
+    app.run_with_args(&[argv0])
+}
+
+fn build_verification_window(app: &adw::Application, url: &str) {
     let content = webkit6::UserContentManager::new();
     content.add_script(&webkit6::UserScript::new(
         BRIDGE,
@@ -53,24 +154,19 @@ pub(crate) fn prompt_human_verification(
         .hexpand(true)
         .build();
 
-    let dialog = adw::Dialog::builder()
+    let body = gtk4::Box::new(gtk4::Orientation::Vertical, 0);
+    body.append(&adw::HeaderBar::new());
+    body.append(&webview);
+    let window = adw::ApplicationWindow::builder()
+        .application(app)
         .title(gettext("Verification"))
-        .content_width(420)
+        .icon_name(APP_ID)
-        .content_height(560)
+        .default_width(420)
+        .default_height(560)
+        .content(&body)
         .build();
 
-    let header = adw::HeaderBar::new();
+    let app = app.downgrade();
-    let body = gtk4::Box::new(gtk4::Orientation::Vertical, 0);
-    body.append(&header);
-    body.append(&webview);
-    dialog.set_child(Some(&body));
-
-    // Taken on the first success *or* on close, so the token is sent at most
-    // once and a cancelled dialog always drops the sender.
-    let token_tx = Rc::new(RefCell::new(Some(token_tx)));
-
-    let tx = token_tx.clone();
-    let dlg_weak = dialog.downgrade();
     content.connect_script_message_received(Some("hv"), move |_, value| {
         let Some(token) = extract_token(&value.to_str()) else {
             // Every `postMessage` on the page reaches here, most of them the
@@ -78,25 +174,17 @@ pub(crate) fn prompt_human_verification(
             // is simply not ours.
             return;
         };
-        if let Some(tx) = tx.borrow_mut().take() {
+        let mut stdout = std::io::stdout().lock();
-            let _ = tx.send(token);
+        if let Err(e) = writeln!(stdout, "{TOKEN_PREFIX}{token}").and_then(|()| stdout.flush()) {
+            tracing::error!("cannot hand the verification token back: {e}");
         }
-        if let Some(dlg) = dlg_weak.upgrade() {
+        if let Some(app) = app.upgrade() {
-            dlg.close();
+            app.quit();
         }
     });
 
-    // Covers the close button, Escape, and the user giving up.
-    dialog.connect_closed(move |_| {
-        token_tx.borrow_mut().take();
-    });
-
     webview.load_uri(url);
-
+    window.present();
-    let parent = ui.login.login_button.root().and_downcast::<gtk4::Window>();
-    // Returns immediately; the login worker stays blocked on the channel until
-    // the handler above sends, or the dialog closes and drops the sender.
-    dialog.present(parent.as_ref());
 }
 
 /// Pull the verification token out of a message posted by the verification page.
@@ -133,7 +221,12 @@ fn extract_token(raw: &str) -> Option<String> {
 
 #[cfg(test)]
 mod tests {
-    use super::extract_token;
+    use super::{Verification, extract_token, find_token, outcome};
+    use std::os::unix::process::ExitStatusExt as _;
+    use std::process::ExitStatus;
+
+    /// The wait status of a process killed by SIGABRT.
+    const ABORTED: i32 = 6;
 
     #[test]
     fn a_completion_message_yields_its_token() {
@@ -163,4 +256,39 @@ mod tests {
             assert!(extract_token(raw).is_none(), "accepted: {raw}");
         }
     }
+
+    #[test]
+    fn the_token_is_found_among_other_output() {
+        let out = "Gtk-Message: something\nhv-token tok-1\nmore\n";
+        assert_eq!(find_token(out.as_bytes()).as_deref(), Some("tok-1"));
+        assert_eq!(find_token("only chatter\n".as_bytes()), None);
+    }
+
+    #[test]
+    fn a_window_closed_without_a_token_cancels() {
+        assert_eq!(
+            outcome(None, ExitStatus::from_raw(0)),
+            Verification::Cancelled
+        );
+    }
+
+    /// WebKit aborts when its sandbox cannot start (B195). That must read as a
+    /// failure the app explains, not as the user giving up.
+    #[test]
+    fn a_window_that_died_fails() {
+        assert_eq!(
+            outcome(None, ExitStatus::from_raw(ABORTED)),
+            Verification::Failed
+        );
+        let exited_1 = ExitStatus::from_raw(1 << 8);
+        assert_eq!(outcome(None, exited_1), Verification::Failed);
+    }
+
+    #[test]
+    fn a_token_counts_even_if_the_window_died_after_it() {
+        assert_eq!(
+            outcome(Some("tok-1".into()), ExitStatus::from_raw(ABORTED)),
+            Verification::Solved("tok-1".into())
+        );
+    }
 }

crates/pdfs-gui/src/app/widgets/crumb.rs

@@ -0,0 +1,21 @@
+use crate::*;
+
+/// The "›" between two breadcrumb segments.
+pub(crate) fn crumb_separator() -> gtk4::Label {
+    let sep = gtk4::Label::new(Some("›"));
+    sep.add_css_class("dim-label");
+    sep
+}
+
+/// The last breadcrumb segment, the folder on screen: a heading rather than a
+/// button. It carries a flat button's side padding (`.crumb-current`), so the
+/// "›" before it sits as far from it as from the button before.
+pub(crate) fn crumb_current(label: &str) -> gtk4::Widget {
+    let l = gtk4::Label::builder()
+        .label(label)
+        .ellipsize(gtk4::pango::EllipsizeMode::Start)
+        .build();
+    l.add_css_class("heading");
+    l.add_css_class("crumb-current");
+    l.upcast()
+}

crates/pdfs-gui/src/app/widgets/file_list.rs

@@ -132,8 +132,13 @@ impl FileList {
                 // and the grid collapses to a single column. Allowing a mid-word
                 // break is what keeps the two-line-then-ellipsis budget below
                 // enforceable for *every* name rather than only the ones that
-                // happen to have spaces.
+                // happen to have spaces. Pango marks such a break with a hyphen
+                // that is not in the name ("SteamSetup.e-xe"); a file name is
+                // not prose, so break it bare, as Nautilus does.
+                let no_hyphens = gtk4::pango::AttrList::new();
+                no_hyphens.insert(gtk4::pango::AttrInt::new_insert_hyphens(false));
                 let label = gtk4::Label::builder()
+                    .attributes(&no_hyphens)
                     .ellipsize(gtk4::pango::EllipsizeMode::End)
                     .justify(gtk4::Justification::Center)
                     .max_width_chars(13)

crates/pdfs-gui/src/app/widgets/menu.rs

@@ -128,20 +128,34 @@ impl ActionMenu {
     }
 }
 
-/// Where a menu opened over `anchor` should live in the widget tree: the
+/// Where a menu opened over `anchor` should live in the widget tree.
-/// outermost grid or list view around it, or `anchor` itself. CSS descendant
+///
-/// selectors reach through a popover to its parent, and themes style the
+/// Not inside a list item: CSS descendant selectors reach through a popover to
-/// insides of list items (`gridview > child box { margin: 12px }` in
+/// its parent, and themes style the insides of list items (`gridview > child
-/// Catppuccin); a menu parented to a tile picks those rules up and puts a wide
+/// box { margin: 12px }` in Catppuccin); a menu parented to a tile picks those
-/// margin around every section. Under the view itself it is no item's child.
+/// rules up and puts a wide margin around every section. So the search starts
+/// at the outermost grid or list view around `anchor`.
+///
+/// Not on a widget without a layout manager either: a popover is sized and
+/// placed again when its parent's layout manager allocates it. The list views
+/// and `ScrolledWindow` have none, so a menu parented there kept the size it was
+/// first given, often too small, and opened scrolling. The host is the first
+/// widget from there up that has one.
 fn popover_host(anchor: &gtk4::Widget) -> gtk4::Widget {
-    let mut host = anchor.clone();
+    let mut start = anchor.clone();
     let mut widget = anchor.parent();
     while let Some(w) = widget {
         widget = w.parent();
         if w.is::<gtk4::GridView>() || w.is::<gtk4::ListView>() || w.is::<gtk4::ColumnView>() {
-            host = w;
+            start = w;
         }
     }
-    host
+    let mut host = Some(start.clone());
+    while let Some(w) = host {
+        if w.layout_manager().is_some() {
+            return w;
+        }
+        host = w.parent();
+    }
+    start
 }

crates/pdfs-gui/src/app/widgets/mod.rs

@@ -1,4 +1,5 @@
 pub(crate) mod compat;
+pub(crate) mod crumb;
 pub(crate) mod details;
 pub(crate) mod file_list;
 pub(crate) mod menu;

crates/pdfs-gui/src/app/widgets/share_dialog.rs

@@ -127,13 +127,33 @@ impl Drop for Busy {
     }
 }
 
+/// A section's action, such as Send Invitations. It goes under the section's
+/// rows, at their right edge, rather than in a row of its own: a row in a boxed
+/// list reads as a setting, and a button alone in one looks misplaced.
+fn group_button(label: &str) -> gtk4::Button {
+    let button = gtk4::Button::builder()
+        .label(label)
+        .halign(gtk4::Align::End)
+        .margin_top(12)
+        .build();
+    button.add_css_class("suggested-action");
+    button
+}
+
+/// A section's only row while the share is being read.
+fn loading_row() -> adw::ActionRow {
+    let row = adw::ActionRow::builder().title(gettext("Loading…")).build();
+    row.add_prefix(&spinner());
+    row
+}
+
 /// How an open Share dialog addresses its node.
 ///
 /// A node the browser is showing has a mountpoint-relative path. A node reached
 /// from Shared or Shared-with-me may not: it can live under a device folder's
 /// own inode space, or on someone else's volume, neither of which the primary
 /// mount's path space can name. Those carry a uid instead, and the daemon
-/// resolves it with `Core::resolve_anywhere` (mount-architecture.md P4).
+/// resolves it with `Core::resolve_anywhere`.
 ///
 /// The two are separate request variants rather than one request with an
 /// optional field on purpose: an older daemon that ignored `uid` would resolve
@@ -287,26 +307,17 @@ pub(crate) fn open_share_dialog(ui: &Rc<Ui>, entry: &DirEntry) {
         .selected(0)
         .valign(gtk4::Align::Center)
         .build();
-    let role_wrap = adw::ActionRow::builder().title(gettext("Role")).build();
+    // The role goes with the addresses it applies to, at the end of their row.
-    role_wrap.add_suffix(&role_drop);
+    role_drop.set_tooltip_text(Some(&gettext("Role")));
+    email_row.add_suffix(&role_drop);
     let message_row = adw::EntryRow::builder()
         .title(gettext("Message (optional)"))
         .build();
-    let invite_btn = gtk4::Button::builder()
+    let invite_btn = group_button(&gettext("Send Invitations"));
-        .label(gettext("Send Invitations"))
-        .halign(gtk4::Align::End)
-        .margin_top(6)
-        .build();
-    invite_btn.add_css_class("suggested-action");
     invite_btn.set_sensitive(false);
-    let invite_wrap = adw::PreferencesRow::builder()
-        .activatable(false)
-        .child(&invite_btn)
-        .build();
     invite_group.add(&email_row);
-    invite_group.add(&role_wrap);
     invite_group.add(&message_row);
-    invite_group.add(&invite_wrap);
+    invite_group.add(&invite_btn);
 
     let people = adw::PreferencesGroup::builder()
         .title(gettext("People with access"))
@@ -315,21 +326,18 @@ pub(crate) fn open_share_dialog(ui: &Rc<Ui>, entry: &DirEntry) {
         .title(gettext("Public link"))
         .build();
 
-    let content = gtk4::Box::new(gtk4::Orientation::Vertical, 18);
+    // Until the share is read, each section says so rather than standing
-    content.set_margin_top(12);
+    // empty under its title.
-    content.set_margin_bottom(12);
+    let people_loading = loading_row();
-    content.set_margin_start(12);
+    people.add(&people_loading);
-    content.set_margin_end(12);
+    let link_loading = loading_row();
-    content.append(&invite_group);
+    link_group.add(&link_loading);
-    content.append(&people);
+
-    content.append(&link_group);
+    let content = adw::PreferencesPage::new();
-    let clamp = adw::Clamp::builder().child(&content).build();
+    content.add(&invite_group);
-    let scroll = gtk4::ScrolledWindow::builder()
+    content.add(&people);
-        .vexpand(true)
+    content.add(&link_group);
-        .hscrollbar_policy(gtk4::PolicyType::Never)
+    toolbar.set_content(Some(&content));
-        .child(&clamp)
-        .build();
-    toolbar.set_content(Some(&scroll));
 
     let dialog = adw::Dialog::builder()
         .title(pgettext("verb", "Share"))
@@ -343,8 +351,8 @@ pub(crate) fn open_share_dialog(ui: &Rc<Ui>, entry: &DirEntry) {
         target,
         people,
         link_group,
-        people_rows: RefCell::new(Vec::new()),
+        people_rows: RefCell::new(vec![people_loading.upcast()]),
-        link_rows: RefCell::new(Vec::new()),
+        link_rows: RefCell::new(vec![link_loading.upcast()]),
     });
 
     // Check the addresses as they are typed: a malformed one marks the row as
@@ -430,17 +438,35 @@ pub(crate) fn share_dialog_reload(state: &Rc<ShareDialog>) {
                 repaint_share_link(&state, link.as_ref());
             }
             Ok(Ok(Response::Error { message, .. })) => {
+                share_dialog_unread(&state);
                 toast_error(&state.ui, &gettext("Couldn't load sharing"), &message)
             }
-            _ => toast_error(
+            _ => {
-                &state.ui,
+                share_dialog_unread(&state);
-                &gettext("Couldn't load sharing"),
+                toast_error(
-                &gettext("The Proton Drive service didn't respond."),
+                    &state.ui,
-            ),
+                    &gettext("Couldn't load sharing"),
+                    &gettext("The Proton Drive service didn't respond."),
+                )
+            }
         }
     });
 }
 
+/// The share couldn't be read: what the sections showed (rows still loading,
+/// or ones that may now be stale) gives way to one line that says so.
+fn share_dialog_unread(state: &Rc<ShareDialog>) {
+    for row in state.people_rows.borrow_mut().drain(..) {
+        state.people.remove(&row);
+    }
+    for row in state.link_rows.borrow_mut().drain(..) {
+        state.link_group.remove(&row);
+    }
+    let row = dim_row(&gettext("Couldn't load sharing"));
+    state.people.add(&row);
+    state.people_rows.borrow_mut().push(row.upcast());
+}
+
 /// Rebuild the "People with access" rows from a fresh share listing.
 pub(crate) fn repaint_share_people(state: &Rc<ShareDialog>, entries: &[ShareEntry]) {
     for row in state.people_rows.borrow_mut().drain(..) {
@@ -455,15 +481,18 @@ pub(crate) fn repaint_share_people(state: &Rc<ShareDialog>, entries: &[ShareEntr
         return;
     }
     for entry in entries {
+        // A member is the plain case and needs no word; an invitation says
+        // it is still waiting on the other side.
         let subtitle = match entry.kind {
-            ShareEntryKind::Member => gettext("Member"),
+            ShareEntryKind::Member => String::new(),
-            ShareEntryKind::ProtonInvite => gettext("Invited (pending)"),
+            ShareEntryKind::ProtonInvite => gettext("Invitation pending"),
-            ShareEntryKind::ExternalInvite => gettext("Invited (external, pending)"),
+            ShareEntryKind::ExternalInvite => gettext("Invitation pending, no Proton account yet"),
         };
         let row = adw::ActionRow::builder()
             .title(&entry.email)
             .subtitle(&subtitle)
             .build();
+        row.add_prefix(&adw::Avatar::new(32, Some(&entry.email), true));
 
         // External invites can't have their role changed; show it read-only.
         // Members and Proton invites get a role dropdown.
@@ -653,16 +682,7 @@ pub(crate) fn repaint_share_link(state: &Rc<ShareDialog>, link: Option<&PublicLi
                 .build();
             let expiry_row = adw::ActionRow::builder().title(gettext("Expires")).build();
             expiry_row.add_suffix(&expiry_drop);
-            let create = gtk4::Button::builder()
+            let create = group_button(&gettext("Create Public Link"));
-                .label(gettext("Create Public Link"))
-                .halign(gtk4::Align::End)
-                .margin_top(6)
-                .build();
-            create.add_css_class("suggested-action");
-            let create_wrap = adw::PreferencesRow::builder()
-                .activatable(false)
-                .child(&create)
-                .build();
 
             // Enter in the password field creates the link.
             let btn = create.clone();
@@ -689,11 +709,11 @@ pub(crate) fn repaint_share_link(state: &Rc<ShareDialog>, link: Option<&PublicLi
             state.link_group.add(&role_row);
             state.link_group.add(&pw_row);
             state.link_group.add(&expiry_row);
-            state.link_group.add(&create_wrap);
+            state.link_group.add(&create);
             rows.push(role_row.upcast());
             rows.push(pw_row.upcast());
             rows.push(expiry_row.upcast());
-            rows.push(create_wrap.upcast());
+            rows.push(create.upcast());
         }
     }
     *state.link_rows.borrow_mut() = rows;

crates/pdfs-gui/src/main.rs

@@ -45,6 +45,8 @@ enum Phase {
     Offline,
     /// Changes keep failing; the user has to look.
     Attention,
+    /// Mounted, but Proton refused the session: only signing in again helps.
+    SessionExpired,
     /// Signed in, but no mount daemon is running.
     Disconnected,
     SignedOut,
@@ -60,6 +62,7 @@ impl Phase {
             Phase::Paused => "media-playback-pause-symbolic",
             Phase::Offline => "network-offline-symbolic",
             Phase::Attention => "dialog-warning-symbolic",
+            Phase::SessionExpired => "dialog-password-symbolic",
             Phase::Disconnected | Phase::SignedOut => "network-offline-symbolic",
         }
     }
@@ -88,8 +91,9 @@ struct DriveState {
 /// Summarise a work snapshot into one menu line, or empty when idle. A single
 /// transfer names the file and its percentage; several collapse to counts so the
 /// menu stays one line regardless of queue depth. With nothing moving bytes, a
-/// running job speaks for itself — a scan or an index rebuild is still "busy",
+/// running job speaks for itself — a scan or an index rebuild is still work
-/// and the tray saying nothing there reads as "finished".
+/// going on, and the menu saying nothing there reads as "finished". The icon is
+/// [`busy`]'s call, not this line's.
 fn sync_line(items: &[TransferItem], jobs: &[JobItem]) -> String {
     match items {
         [] => match jobs.first() {
@@ -143,12 +147,12 @@ struct DriveTray {
 fn poll_state(socket: &Path, default_mountpoint: &Path) -> DriveState {
     match send(socket, &Request::Status) {
         Ok(status @ Response::Status { .. }) => {
-            // Same daemon is up, so a cheap follow-up request gives the sync line.
+            // Same daemon is up, so a cheap follow-up request says what moves.
-            let sync = match send(socket, &Request::GetQueueStatus) {
+            let (items, jobs) = match send(socket, &Request::GetQueueStatus) {
-                Ok(Response::Transfers { items, jobs }) => sync_line(&items, &jobs),
+                Ok(Response::Transfers { items, jobs }) => (items, jobs),
-                _ => String::new(),
+                _ => (Vec::new(), Vec::new()),
             };
-            status_state(&status, sync, default_mountpoint)
+            status_state(&status, &items, &jobs, default_mountpoint)
         }
         // Socket answered but with something unexpected — treat as up but odd.
         Ok(_) => unexpected_reply(default_mountpoint),
@@ -166,6 +170,15 @@ fn poll_state(socket: &Path, default_mountpoint: &Path) -> DriveState {
         // No daemon: describe login state instead so the menu is still useful.
         Err(_) => {
             let (line, phase) = match auth::load() {
+                Ok(s) if matches!(auth::key_state(), Ok(auth::KeyState::Locked)) => (
+                    // Translators: {username} is the Proton account name. The
+                    // account has a mailbox password that has to be entered.
+                    gettext_f(
+                        "Signed in as {username} — locked",
+                        &[("username", &s.username)],
+                    ),
+                    Phase::Attention,
+                ),
                 Ok(s) => (
                     // Translators: {username} is the Proton account name.
                     gettext_f(
@@ -208,9 +221,14 @@ fn unexpected_reply(default_mountpoint: &Path) -> DriveState {
     }
 }
 
-/// The state a running daemon's [`Response::Status`] describes, with `sync`
+/// The state a running daemon's [`Response::Status`] describes, with `items`
-/// saying what it is moving right now.
+/// and `jobs` saying what it is working on right now.
-fn status_state(status: &Response, sync: String, default_mountpoint: &Path) -> DriveState {
+fn status_state(
+    status: &Response,
+    items: &[TransferItem],
+    jobs: &[JobItem],
+    default_mountpoint: &Path,
+) -> DriveState {
     let Response::Status {
         mountpoint,
         pinned,
@@ -219,6 +237,8 @@ fn status_state(status: &Response, sync: String, default_mountpoint: &Path) -> D
         pending_changes,
         failing_ops,
         paused,
+        session_expired,
+        tokens_unsaved,
         ..
     } = status
     else {
@@ -226,14 +246,25 @@ fn status_state(status: &Response, sync: String, default_mountpoint: &Path) -> D
     };
     let (pinned, online, failing_ops, paused) = (*pinned, *online, *failing_ops, *paused);
     let queued = i18n::pending_summary(*pending_uploads, *pending_changes);
-    let phase = phase_of(
+    let phase = if *session_expired {
-        paused,
+        Phase::SessionExpired
-        failing_ops,
+    } else if *tokens_unsaved {
-        online,
+        Phase::Attention
-        queued.is_some() || !sync.is_empty(),
+    } else {
-    );
+        phase_of(
+            paused,
+            failing_ops,
+            online,
+            queued.is_some() || busy(items, jobs),
+        )
+    };
     DriveState {
         line: match (online, queued) {
+            // Outranks everything: it is why nothing else moves, and the one
+            // thing that fixes it is the user's to do.
+            _ if *session_expired => gettext("Session expired — sign in again"),
+            // Sync goes on meanwhile, but a reboot ends it until the next login.
+            _ if *tokens_unsaved => gettext("Sign-in not saved — unlock your keyring"),
             _ if paused => gettext("Sync paused"),
             _ if failing_ops > 0 => ngettext_f(
                 "{n} change needs attention",
@@ -269,11 +300,19 @@ fn status_state(status: &Response, sync: String, default_mountpoint: &Path) -> D
         mounted: true,
         paused,
         mountpoint: PathBuf::from(mountpoint),
-        sync,
+        sync: sync_line(items, jobs),
         failing: failing_ops,
     }
 }
 
+/// Whether the daemon is changing something: bytes moving, or a job the user
+/// is waiting on. A mirror folder's routine scan and the like are background
+/// jobs; they still get the menu line, but the icon spinning every two minutes
+/// for a scan that finds nothing reads as constant syncing.
+fn busy(items: &[TransferItem], jobs: &[JobItem]) -> bool {
+    !items.is_empty() || jobs.iter().any(|j| !j.background)
+}
+
 /// The phase a running mount is in. A pause is the user's own doing and says
 /// so first; failures outrank everything else the daemon reports.
 fn phase_of(paused: bool, failing: u64, online: bool, busy: bool) -> Phase {
@@ -342,7 +381,7 @@ impl Tray for DriveTray {
 
     fn status(&self) -> Status {
         match self.state.phase {
-            Phase::Attention => Status::NeedsAttention,
+            Phase::Attention | Phase::SessionExpired => Status::NeedsAttention,
             _ => Status::Active,
         }
     }
@@ -400,6 +439,9 @@ impl Tray for DriveTray {
             // Nothing to mount without a session; the app's sign-in page is the
             // way in.
             Phase::SignedOut => items.push(item(&gettext("Sign In…"), |_| open_manager(&[]))),
+            Phase::SessionExpired => items.push(item(&gettext("Sign In Again…"), |_| {
+                open_manager(&["--page", "login"])
+            })),
             _ => items.push(item(&gettext("Open Proton Drive"), |_| open_manager(&[]))),
         }
 
@@ -476,6 +518,10 @@ fn main() -> Result<()> {
         return Ok(());
     }
 
+    // The socket lives in the state dir, which nothing has made yet when the app
+    // starts the tray on a fresh install (B194).
+    dirs.ensure().context("create the app's directories")?;
+
     // Ensure only one instance of the tray runs.
     let tray_sock = dirs.tray_socket();
     if std::os::unix::net::UnixStream::connect(&tray_sock).is_ok() {
@@ -534,11 +580,7 @@ fn main() -> Result<()> {
             heard.take(feed);
         }
         let st = match &heard.status {
-            Some(status) => status_state(
+            Some(status) => status_state(status, &heard.items, &heard.jobs, &default_mountpoint),
-                status,
-                sync_line(&heard.items, &heard.jobs),
-                &default_mountpoint,
-            ),
             // Lost the daemon: ask once, which describes the sign-in instead.
             None => poll_state(&socket, &default_mountpoint),
         };
@@ -583,6 +625,80 @@ mod tests {
         assert_eq!(phase_of(false, 0, true, false), Phase::Synced);
     }
 
+    fn status(extra: &str) -> Response {
+        serde_json::from_str(&format!(
+            r#"{{"Status":{{"username":"u","mountpoint":"/m","pinned":0,"used":0,"budget":0,
+                "pins":[],"online":false,"pending_uploads":3,"failing_ops":2,"paused":true{extra}}}}}"#
+        ))
+        .unwrap()
+    }
+
+    /// Issue #35: a refused session read as "Offline — 3 uploads queued" for
+    /// good, and nothing said that signing in again was the way out.
+    #[test]
+    fn a_refused_session_outranks_everything_else() {
+        let state = status_state(
+            &status(r#","session_expired":true"#),
+            &[],
+            &[],
+            Path::new("/m"),
+        );
+        assert_eq!(state.phase, Phase::SessionExpired);
+        assert_eq!(state.line, "Session expired — sign in again");
+    }
+
+    /// B61: the keyring refusing the refreshed tokens was only in the log.
+    #[test]
+    fn a_sign_in_the_keyring_refused_needs_attention() {
+        let state = status_state(
+            &status(r#","tokens_unsaved":true"#),
+            &[],
+            &[],
+            Path::new("/m"),
+        );
+        assert_eq!(state.phase, Phase::Attention);
+        assert_eq!(state.line, "Sign-in not saved — unlock your keyring");
+    }
+
+    #[test]
+    fn a_daemon_that_does_not_say_has_a_live_session() {
+        let state = status_state(&status(""), &[], &[], Path::new("/m"));
+        assert_eq!(state.phase, Phase::Paused);
+    }
+
+    fn job(title: &str, background: bool) -> JobItem {
+        JobItem {
+            title: title.to_string(),
+            detail: String::new(),
+            done: 0,
+            total: 0,
+            background,
+        }
+    }
+
+    #[test]
+    fn a_routine_scan_is_not_busy_but_a_sync_is() {
+        assert!(!busy(&[], &[]));
+        assert!(!busy(&[], &[job("Checking Documents", true)]));
+        assert!(busy(
+            &[],
+            &[
+                job("Checking Documents", true),
+                job("Syncing Photos", false)
+            ]
+        ));
+        assert!(busy(&[], &[job("Uploading files", false)]));
+    }
+
+    #[test]
+    fn a_job_from_an_older_daemon_counts_as_busy() {
+        let job: JobItem = serde_json::from_str(
+            r#"{"title":"Checking Documents","detail":"","done":0,"total":0}"#,
+        )
+        .unwrap();
+        assert!(!job.background);
+    }
+
     #[test]
     fn the_issues_item_counts_in_the_singular_and_plural() {
         assert_eq!(issues_label(1), "1 issue — View");

crates/pdfs-gui/tests/icon_names.rs

@@ -28,6 +28,7 @@ const STOCK: &[&str] = &[
     "checkbox-symbolic",
     "computer-symbolic",
     "dialog-error-symbolic",
+    "dialog-password-symbolic",
     "dialog-warning-symbolic",
     "document-edit-symbolic",
     "document-open-recent-symbolic",

docs/CHANGELOG.md

@@ -11,6 +11,358 @@ scratch (user data in `staging/` and `recovery/` is never touched by this).
 
 ## [Unreleased]
 
+### Fixed
+- **Writing to a file again soon after a partial write could fail with an I/O error.** When the
+  first write changed only part of a file this client had not read, a second write, or saving
+  over the file, failed until the first one reached Drive. It now fetches the rest of the file
+  and goes ahead.
+- **A CAPTCHA could not be solved on hardened systems.** When the verification page cannot open in
+  the app, as on secureblue, the app now offers it in your browser and continues the sign-in
+  once you are done. `pdfs login` now handles a CAPTCHA the same way instead of failing.
+  ([#29](https://github.com/narrrl/proton-drive-linux/issues/29))
+
+## [3.2.0] — 2026-10-08
+
+Schema: **42**, unchanged.
+
+### Fixed
+- **One unreadable folder stopped a synced folder from syncing at all.** A folder you may not
+  read, such as a cache a container created, failed every pass, so nothing else in the synced
+  folder reached Drive. Such a folder is now left out and named once in the activity feed, and
+  everything around it syncs. A file deleted during a scan, and a name that is not UTF-8, no
+  longer fail the pass either.
+  ([#33](https://github.com/narrrl/proton-drive-linux/issues/33))
+- **Switching a folder to online-only could delete files that were never on Drive.** Ignored
+  folders such as `.git/`, symlinks, unreadable folders and files changed after the last sync were
+  deleted with the local copy. The switch now refuses and names what is only on this computer.
+- **Switching to online-only trashed synced files that had become ignored.** Adding a synced path
+  to `.pdfsignore` and then switching moved it to the Drive trash. Ignoring never deletes now, as
+  the user guide says.
+- **A stopped share stayed on the Shared by me page for minutes.** Stop Sharing now takes it off
+  the page at once, and an emptied share no longer shows with no people and no link.
+- **The tray icon showed syncing every two minutes.** The routine check of a synced folder no
+  longer counts as syncing. Only work that changes files spins the icon. An edit in one synced
+  folder also no longer rescans all the others.
+- **Right-click menus sometimes opened too short and had to be scrolled.**
+- **The Share dialog looked unfinished.** Its buttons now sit under their sections instead of in a
+  row of their own. The role is chosen beside the addresses, people show with avatars, and both
+  sections show that they are loading.
+- **Breadcrumbs spaced the "›" unevenly, and grid file names were broken with hyphens they do not
+  have.**
+
+### Changed
+- **One main menu.** The menu button beside "Proton Drive" is gone. Preferences, Keyboard
+  Shortcuts, About and Sign Out are all in the account row at the bottom of the sidebar. F10 opens
+  it.
+
+### Added
+- **Move another computer's backup to this one.** **Move to This Computer…** on the Computers page,
+  or `pdfs devices migrate UID`, moves every folder another computer backs up, for example an old
+  Windows PC, into this computer's backup on Proton Drive. Then it offers them for syncing here. The
+  folders move on Proton Drive itself, so nothing is uploaded again. The other computer stays in the
+  account, without those folders.
+
+## [3.1.2] — 2026-10-08
+
+Schema: **42**, unchanged.
+
+### Fixed
+- **The app crashed when Proton asked for a CAPTCHA on hardened systems.** On secureblue, WebKit
+  cannot start the sandbox for the verification page and ends its process, which took the app
+  down with it. The page now opens in a separate window process: if that process fails, the
+  sign-in stops with a message that says why, and TROUBLESHOOTING.md has a workaround.
+  ([#29](https://github.com/narrrl/proton-drive-linux/issues/29))
+- **On a fresh install the tray icon did not start.** The tray and the app now create their state
+  directory themselves instead of waiting for the service to do it. This also lets the Takeout
+  page remember staged archives before the first mount.
+  ([#29](https://github.com/narrrl/proton-drive-linux/issues/29))
+
+## [3.1.1] — 2026-10-07
+
+Schema: **42**, unchanged.
+
+### Changed
+- **The client identifies itself with its release.** Sign-in and every API call used to send the
+  fixed `external-drive-linux@0.1.0-alpha` and `proton-drive-linux/0.1.0`. If Proton retired that
+  version, every release would fail to sign in at once and no update could fix it. The client now
+  sends `external-drive-linux@<version>-stable` and `proton-drive-linux/<version>`. `app_version`
+  and `user_agent` in `config.json` are optional overrides now. The fixed values that releases up
+  to 3.1.0 wrote there count as unset and are removed on the next save. A value you set by hand is
+  kept.
+- The About dialog shows the release version, and its debug info shows the identity that is
+  actually sent.
+
+## [3.1.0] — 2026-10-07
+
+Schema: **42**, unchanged.
+
+### Added
+- **Two-password accounts.** An account with a separate mailbox password now signs in: the app
+  and `pdfs login` ask for it after the login password and check it against the account, so a
+  typo is a retry and not a daemon that never mounts. The mailbox password is never stored.
+  What it unlocks is kept in kernel memory for the login session, so it is asked for once per
+  session and is gone after a reboot or when you log out of the machine.
+- **`pdfs unlock` and `pdfs lock`.** `pdfs unlock` enters the mailbox password of a locked
+  account and starts the daemon's mount; `pdfs lock` forgets it again. `--remember` on `login`
+  and `unlock` (and the "Keep unlocked on this computer" switch in the app) keeps the unlock in
+  the system keyring instead, so the daemon starts without asking; `pdfs lock --forget` removes
+  it. Off by default: it gives up the separation a second password is for.
+- **Locked state.** `pdfs status`, `pdfs diagnose` and the tray say when the account is waiting
+  for its mailbox password, and the app asks for it when it opens.
+
+### Changed
+- **The keyring no longer holds a password.** The session blob keeps the keys' passphrases
+  instead of the mailbox password, and a blob written by 3.0.x is converted on the first start.
+  A stored password the account rejects (a two-password account that was signed in with only
+  its login password) leaves the account locked instead of failing every start.
+- **The daemon is not dumpable.** It holds the unlock in memory, so core dumps and same-user
+  `ptrace` are off for it.
+- **The offline cache is re-keyed** from the new secret, so the first start after the update
+  reads it as cold and fetches the tree again once.
+
+### Fixed
+- **systemd killed a daemon that was only retrying.** `WatchdogSec` was answered only once a
+  mount existed, so a daemon waiting for a login or retrying a failed mount was aborted after
+  two minutes and restarted in a loop, hiding the error it logged. It now answers the watchdog
+  while it waits. ([#26](https://github.com/narrrl/proton-drive-linux/issues/26))
+- **A refreshed token could overwrite a newer unlock or revive a signed-out session.** Token
+  rotation now updates only the tokens in the stored blob.
+
+## [3.0.0] — 2026-10-05
+
+Schema: **42**. The queue table is rebuilt so an id is never given out twice; queued changes
+are kept. Queued changes get a column for the reason Drive refused them, and two for the
+content a new file was sent with and where, and name their file and folder by local id as well
+as by Drive's id. Stored files and folders name their parent
+folder by local id too. A file or folder made on this machine that Drive does not have yet goes
+by its local id, in the queue, the stored tree and pins alike.
+
+### Added
+- **Sync issues.** A change Drive refuses because the storage is full, access was taken away,
+  its folder is gone, a folder limit is reached or Drive rejected it shows up at once as needing
+  attention, with what it means and what to do, instead of after six failed attempts. The
+  change stays queued and is still retried.
+- **Export a queued file.** The Sync page's Export button and `pdfs sync export <id> <dest>`
+  save a copy of a queued upload's content. The upload stays queued.
+- **`pdfs sync issues`** lists the changes that need attention; `pdfs sync queue` shows the
+  issue next to each change.
+- **Discard a queued change.** The Sync page's Discard button and `pdfs sync discard <id>` drop
+  a change Drive will not take and undo it here: a new file or folder goes, anything else goes
+  back to what Drive has. Export a file first to keep its content.
+- **Sync issues show on the file.** A file or folder with a change Drive refused carries a
+  warning badge in the file browser, and its tooltip says what it means and what to do.
+
+### Changed
+- **Making, renaming and deleting through the mount no longer waits for Drive.** A new folder,
+  a new file, a rename or a delete is recorded locally and the call returns at once; the queue
+  sends it, as it does offline. `"local_first": false` in `config.json` brings back the old way
+  for this release.
+- **The queue sends up to 16 changes at once instead of 3.** A thousand new files in a hundred
+  folders reach Drive about three times as fast on a LAN, and four times as fast on Wi-Fi.
+
+### Fixed
+- **A file made under the name of a file whose upload is still going out keeps its name.** It
+  no longer lands as a conflict copy, and the mount no longer shows that copy's name (B154).
+- **A change to a file no longer lands as a conflict copy of itself when the link loses Drive's
+  answer to its upload** (B155).
+- **A file written again while its upload was being retried no longer lands as a conflict copy
+  of itself when the link lost Drive's answer to the first try** (B156).
+- **Writing to a file twice in a row no longer fails with "Input/output error" when the link
+  lost Drive's answer to reading back the file's last upload** (B157).
+- **A file renamed twice in a row, while the first name was still taken, keeps the second name**
+  (B158).
+- **Opening a file right after the daemon restarts no longer fails with "Resource temporarily
+  unavailable"** (B159).
+- **A new folder, or a new empty file, reaches Drive at once**, not up to half a minute later
+  (B160, B192).
+- **A file moved while it was still being uploaded keeps its new name in the mount** on a slow
+  link (B161).
+- **A folder removed and made again at once keeps what goes into it.** It used to be created
+  inside the removed folder and was trashed along with it (B162).
+- **A new file no longer reads as empty just after it is uploaded.** Drive can list it a moment
+  before its contents are committed, and the mount took that answer (B163).
+- **A folder no longer lists a new file twice while it is uploaded.** A listing taken as the
+  upload landed showed it both as Drive had it and as the queue did (B164).
+- **Stopping the daemon no longer hangs until systemd kills it.** A stop waits up to 10 s for
+  work in progress, then exits and logs what was still running (B165).
+- **A folder no longer drops or empties a new file while others are uploaded.** A file whose
+  upload landed while the folder was being listed was missing from that listing, or listed as
+  empty (B166).
+- **The mount comes up faster on a large Drive.** Rebuilding the folder listings from the cache
+  took close to 2 s with 37,000 files at every start (B167).
+- **Files deleted with their folder while uploading stay deleted.** The mount no longer tries
+  to upload them to the top of your Drive instead (B168).
+- **Stopping the daemon during a folder sync no longer waits for the sync.** The uploads in
+  progress finish, and the rest waits for the next start (B169).
+- **Writing to a file again just as its upload finishes no longer fails.** A write right after
+  it failed with "Input/output error" (B170).
+- **A file deleted while its upload was retrying is removed from Drive right away.** It no
+  longer waits for the upload's next retry (B171).
+- **A file deleted just as it reached Drive is removed from Drive too.** It no longer stayed
+  there, and the next file with that name no longer became a conflict copy (B173).
+- **Renaming a file just as it reaches Drive no longer fails with "Permission denied"**
+  (B174).
+- **A file replaced by a rename just as it reached Drive is removed from Drive too.** It no
+  longer stayed there, and the next rename of its name no longer moved it instead (B175).
+- **A write closed just as its file reached Drive is no longer lost** (B176).
+- **Opening a folder just as it reaches Drive no longer fails with "Input/output error"**
+  (B177).
+- **Deleting a folder while sync is paused no longer leaves a queued change behind** for a
+  file in it that was never uploaded (B178).
+- **A file read just as it reaches Drive no longer reads empty** (B179).
+- **Stopping the daemon no longer takes 10 seconds more than it needs** when an idle upload
+  worker missed the stop (B180).
+- **A folder made while offline or with sync paused no longer fails with "Input/output
+  error"** once it is refreshed or the connection comes back (B125).
+- **The daemon no longer hangs when a file being read changes on Drive** (B130).
+- **The Activity page says in your language why an edit was kept as a conflicting copy**,
+  instead of the daemon's English (B181).
+- **A file written after a restart no longer lands as a conflict copy of itself** when the
+  connection dropped just as it first reached Drive (B182).
+- **A file deleted after a restart is removed from Drive too** when the connection lost Drive's
+  answer to its upload and the file was written again meanwhile. It no longer stayed there and
+  turned the next file under its name into a conflict copy (B183).
+- **A file renamed while the connection lost Drive's answer to its upload lands once.** It no
+  longer stayed on Drive under its old name too, or, when deleted, under its old name alone
+  (B184).
+- **A new file written again just as it starts uploading no longer waits out a retry** before
+  it reaches Drive (B185).
+- **A file deleted while open can still be read and written until it is closed**, offline too.
+  A write into it no longer failed with "Input/output error" (B186).
+- **An uploaded file no longer leaves a copy of itself in the cache** until the next start
+  (B187).
+- **Changes that failed during a short outage go out soon after the connection is back**, not
+  after a retry delay of up to five minutes (B189).
+- **A file saved just before the daemon stops reaches Drive** with what was written. It could
+  keep its old content, or stay empty (B190).
+- **A file renamed just as its upload finished keeps its new name.** The mount no longer showed
+  the old name, and a second rename no longer failed with "No such file or directory" (B152,
+  B172).
+- **A change that waits for a name to be freed no longer waits seconds after it is.** A rename or
+  upload over a file being deleted goes out as soon as the delete lands (B153).
+- **A file deleted right after it was made no longer stays on Drive when the link lost Drive's
+  answer.** The node Drive made is trashed (B151).
+- **A new file no longer lands twice when the link loses Drive's answer to its upload.** The
+  file Drive made is taken as it is, instead of a second upload as a conflict copy (B127).
+- **A change to a file deleted elsewhere, together with its folder, no longer retries forever.**
+  The conflict copy that keeps it now lands in the location's root (B150).
+- **`pdfs rename` and `pdfs move` right after a change through the mount are no longer undone.**
+  They are queued behind it, and they work on a file that has not reached Drive yet (B149).
+- **A folder kept offline before it reached Drive stays kept offline.** Its pin was lost when the
+  folder landed (B148).
+- **A queued change no longer holds up the queue forever on a link that stops answering.**
+  Sending a new folder, a delete or a file waits at most 20 seconds for Drive, plus time for
+  the file's size, and then the queue treats the link as down and tries again.
+- **A file deleted while its first upload is on the wire no longer stays on Drive.** The node
+  the upload made is trashed as soon as it lands, so its name is free again (B129).
+- **A delete queued while a rename is sent is no longer lost.** The rename landing could remove
+  the delete from the queue, leaving the file on Drive (B137).
+- **A file made offline over one deleted offline is no longer lost.** Its upload could take
+  over the deleted file, and the delete then took the new bytes along with it (B128).
+- **A file deleted while its upload is on the wire no longer comes back as a `recovered-…`
+  copy** when another file is made right after (B133).
+- **A file made where another one is leaving no longer lands as a conflict copy.** Its upload
+  waits for the rename or trash that frees the name (B126, B138).
+- **A file closed just as its first upload lands keeps its last write.** The write was refused
+  and left in staging (B139).
+- **Files made in a new folder are still there after a restart.** A folder that landed as the
+  daemon stopped, or one listed from Drive while files in it were queued, came back empty
+  (B132, B140).
+- **A file renamed twice in quick succession ends up under the second name.** The first rename
+  could land after the second and undo it (B141).
+- **Renaming a new file just as its upload lands no longer fails with "Device or resource
+  busy".** The rename goes to the file Drive made (B142).
+- **A file whose upload landed just as the connection dropped no longer gets a conflict copy at
+  its next save.** The daemon reads the file back once the connection returns (B143).
+- **A rename whose target name was just freed no longer lands as a conflict copy.** The rename
+  is sent once more under the name it asked for (B144).
+- **Saving a download under its final name no longer fails with "Device or resource busy".**
+  A file made a moment before was taken for deleted and dropped from the queue (B145).
+- **A file renamed just as its upload lands keeps its new name.** The tree could take back the
+  name Drive still had (B146).
+- **A new file made under a name another file just left no longer takes that file's place on
+  Drive.** Both could land on one node, and one file's content was lost (B147).
+
+## [2.10.0] — 2026-10-03
+
+Schema: **36**. Every node row gets a local id that never changes; existing rows keep their
+row number as that id. Going back to 2.9 means rebuilding the cache. Requires `proton-drive-rs`
+**0.7.2**.
+
+### Added
+- **Migration tests on real databases.** A database 2.8.2 wrote, with queued changes due,
+  parked, failing, waiting for access and in flight, migrates with every change intact.
+  `PDFS_MIGRATE_DB=<path> cargo test -p pdfs-core a_copy_of_a_real_database -- --ignored` runs
+  the same check on a read-only copy of any database.
+
+### Changed
+- **A file keeps its inode number across daemon restarts.** Inodes are now the node's local id
+  instead of a counter that started over on every run.
+- **Every mount serves from one tree.** An on-demand sync folder used to keep its own copy of the
+  nodes it showed, which background work had to visit one by one and could miss (B74). It now
+  shares the tree with My files; only the root it starts at is its own.
+
+### Fixed
+- **A file renamed or moved while its first upload is on the wire keeps its new name and folder.**
+  It landed under the old name and the rename was lost (B136).
+
+## [2.9.0] — 2026-10-03
+
+Schema: **35** (unchanged). Requires `proton-drive-rs` **0.7.2**.
+
+### Added
+- **Seeded simulation runs.** `cargo test -p pdfs-fuse --lib sim:: -- --ignored
+  --test-threads=1` mounts one or more real FUSE daemons against an in-memory Drive that lags,
+  drops, reorders and echoes like the real one. Each seed draws syscalls, link flaps and restarts,
+  checks every answer against a POSIX model, and at the end checks that nothing was lost and the
+  clients converged. CI runs them on pushes to main. They found B122 to B135.
+- **More acceptance cases.** Regressions for B48, B80, B86, B88, B94, B95, B98, B102, B111, B113
+  and B114 to B121, and a check that `pdfs` output into a closed pipe stays quiet. The console
+  report has one line per case and a summary table, and `--journal-check` also fails on a
+  conflict copy, a FUSE job held for long, or an authority re-read.
+
+### Fixed
+- **A new file moved or renamed before its first upload no longer lands as a conflict copy**
+  next to its own empty original (B113).
+- **`pdfs rm`, `pdfs rename` and `pdfs mkdir` take paths in on-demand folders.** They answered
+  "is not under the mountpoint" for a path `pdfs move` took. `rm` and `rename` refuse a path that
+  names a mount's root (B88).
+- **`pdfs ls | head` no longer panics** with "Broken pipe". A closed stdout exits 0; any other
+  write error exits 1.
+- **A file removed, renamed or moved with `pdfs` stops resolving under its old name at once**,
+  instead of for up to 30 seconds (B114).
+- **`pdfs ls` and the app's file browser show a file's real size**, not its encrypted one
+  (B115).
+- **Trashing a folder also drops the creates queued in its subfolders.** One could stay queued
+  with its bytes, or land in the root (B116).
+- **An upload queued for a file `pdfs move` moved keeps its path** in `pdfs sync queue` and is
+  no longer put off once after the resume (B117).
+- **Creating a file or folder through the mount no longer fails with `ENOENT`** when Drive is
+  slow to list what it made. The mount asks again, and queues the create if it still cannot see
+  it (B118).
+- **A file just written can be read without the network.** Its uploaded bytes stay cached, and
+  `pdfs status` counts the upload as pending until they are (B119).
+- **A file queued inside a folder that just landed is no longer put off** for five seconds
+  (B120).
+- **A move right after a rename lands.** It failed with `Input/output error` through the mount
+  and with "out of date" from `pdfs move`, and a rename across folders took up to 10 seconds
+  (B111, B121).
+- **A rename across folders no longer fails with `Input/output error`** when the source folder
+  holds the new name (B122).
+- **A second write open on a file just written no longer fails** with `Input/output error`
+  (B123).
+- **After a replacing rename fails, the file it was replacing stays in the mount** (B124).
+- **A write to a file whose create could not be read back no longer lands as a conflict copy**
+  (B131).
+- **A file just moved is found by its new path.** A lookup right after the rename could miss it
+  (B135).
+
+### Notes
+- The simulation runs found bugs that are still open: B125 to B130 and B132 to B134 in
+  `docs/BUGS.md`. The worst are B127 and B128 (a file created offline can land twice, or be lost
+  when created over one deleted offline), B129 (a file deleted while its create is on the wire
+  stays on Drive) and B130 (a read that a remote change invalidates can hang the daemon).
+
 ## [2.8.2] — 2026-10-01
 
 Schema: **35** (unchanged). Requires `proton-drive-rs` **0.7.2**.
@@ -1364,6 +1716,18 @@ First stable release: FUSE files-on-demand mount, sync daemon under `proton-driv
 - The outstanding FUSE defects tracked in `docs/BUGS.md`, plus a truncate defect, validated
   by a new POSIX compliance suite for the filesystem.
 
+[3.2.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v3.2.0
+
+[3.1.2]: https://github.com/narrrl/proton-drive-linux/releases/tag/v3.1.2
+
+[3.1.1]: https://github.com/narrrl/proton-drive-linux/releases/tag/v3.1.1
+
+[3.1.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v3.1.0
+
+[3.0.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v3.0.0
+
+[2.10.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v2.10.0
+[2.9.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v2.9.0
 [2.8.2]: https://github.com/narrrl/proton-drive-linux/releases/tag/v2.8.2
 [2.8.1]: https://github.com/narrrl/proton-drive-linux/releases/tag/v2.8.1
 [2.8.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v2.8.0

docs/CLI.md

@@ -82,6 +82,9 @@ commands are for scripts and for cases where the mount is not available.
 | `pdfs sync resume [--folder ID]` | Resume after a pause. |
 | `pdfs sync limit [--up RATE] [--down RATE]` | Cap bandwidth, for example `500K` or `2M` per second. `0` removes a cap. Without options, prints the current caps. |
 | `pdfs sync queue` | List changes that have not reached Proton Drive yet. |
+| `pdfs sync issues` | List queued changes Proton Drive refused or that keep failing, and what to do. |
+| `pdfs sync export ID DEST` | Save a copy of a queued upload's content. `DEST` may be a folder; an existing file is never overwritten. The upload stays queued. |
+| `pdfs sync discard ID [--yes]` | Drop a queued change and undo it here: a new file or folder goes, anything else goes back to what Proton Drive has. Content not exported first is lost. |
 | `pdfs sync retry [ID]` | Retry one queued operation, or every failed one. |
 | `pdfs sync restore [--device UID] [--yes]` | Re-attach this computer's backed-up folders to local folders and download them. `--device` restores another computer's folders. See [RECOVERY.md](RECOVERY.md). |
 
@@ -100,6 +103,7 @@ commands are for scripts and for cases where the mount is not available.
 | `pdfs devices rename UID NAME` | Rename a computer. |
 | `pdfs devices rm UID` | Remove a computer and its backup from the account. |
 | `pdfs devices adopt UID` | Make this machine continue another computer's backup, for example after a reinstall. `--clear` returns to matching by hostname. |
+| `pdfs devices migrate UID [--yes]` | Move another computer's folders into this computer's backup, then restore them here like `pdfs sync restore`. The other computer stays registered, without those folders. `--yes` skips the confirmation and accepts every proposed path. See [RECOVERY.md](RECOVERY.md). |
 
 ## Trash
 

docs/CONFIGURATION.md

@@ -38,7 +38,7 @@ Inside `content/`:
 > not reached Proton Drive and exists nowhere else.
 
 Everything in these directories except the keyring is **decrypted**. See
-[ARCHITECTURE.md §8](ARCHITECTURE.md#8-threat-model-what-this-client-writes-to-disk-in-plaintext).
+[ARCHITECTURE.md §10](ARCHITECTURE.md#10-threat-model-what-this-client-writes-to-disk-in-plaintext).
 
 ## `config.json`
 
@@ -80,6 +80,7 @@ fix it.
 | `ignore_patterns` | list | see below | — | Global ignore rules for synced folders |
 | `device_uid` | string | none | Computers → Continue This Backup Here… | The computer this machine continues. Unset means "match by hostname" |
 | `conflict_sweep` | `off` / `report` / `enforce` | `report` | — | See [`conflict_sweep`](#conflict_sweep) |
+| `local_first` | bool | `true` | — | See [`local_first`](#local_first) |
 | `language` | gettext code | system | General → Appearance | Language of the app, tray and prompt, such as `de` or `pt_BR` |
 | `proton_theme` | bool | follow system | General → Appearance | Proton's colours instead of the system theme |
 | `online_map` | bool | `false` | General → Appearance | Street map for Places from OpenFreeMap |
@@ -88,7 +89,11 @@ fix it.
 | `open_with` | object | `xdg-open` | — | See [`open_with`](#open_with) |
 | `prompt` | object | built-in window | — | See [`prompt`](#prompt) |
 
-`app_version` and `user_agent` identify the client to Proton. Leave them alone.
+`app_version` and `user_agent` identify the client to Proton. When the keys are absent, the
+client sends its own release (`external-drive-linux@<version>-stable`, `proton-drive-linux/<version>`).
+Leave them out unless a support case asks for a different value. The fixed
+`external-drive-linux@0.1.0-alpha` and `proton-drive-linux/0.1.0` that releases up to 3.1.0 wrote
+here are treated as absent and removed on the next save.
 
 ### `ignore_patterns`
 
@@ -116,6 +121,15 @@ were copied from.
 
 `PDFS_CONFLICT_SWEEP` overrides the setting for one run of the service.
 
+### `local_first`
+
+A new folder, a new file, a rename or a delete made through the mount is recorded locally and the
+call returns at once. The change goes to Drive from the queue, the same way it does offline, and
+`pdfs status` counts it until it lands.
+
+Set it to `false` to have these calls wait for Drive again, as before 3.0.0. The switch is there
+for one release, in case the queued path misbehaves for you; please report it if it does.
+
 ### `open_with`
 
 Decides how files picked in the search launcher or the app are opened. Rules are tried in order;
@@ -180,13 +194,16 @@ Command-line flags win over the file: `--gtk`, `--dmenu`, `--fzf` and `--menu`.
 | `PDFS_LOCALEDIR` | app, tray, prompt | Load translations from another directory (development) |
 | `PDFS_STAND_IN_WIDGETS` | app | `1` uses the libadwaita 1.5 fallback widgets on newer systems (development) |
 
-The acceptance suite has its own `PDFS_ACCEPTANCE_*` variables, listed in [TESTING.md](TESTING.md).
+The tests have their own variables (`PDFS_ACCEPTANCE_*`, `PDFS_SIM_*`, `PDFS_MIGRATE_DB`),
+listed in [TESTING.md](TESTING.md).
 
 ## The systemd service
 
-`proton-drive.service` is a user unit. It restarts the service whenever it exits, restarts it when
+`proton-drive.service` is a user unit started with your graphical session
-it stops answering for two minutes (`WatchdogSec=120`), and caps its memory at 6 GiB. To change
+(`WantedBy=graphical-session.target`). It restarts the service whenever it exits, restarts it
-the unit without editing the packaged file, use a drop-in:
+when it stops answering for two minutes (`WatchdogSec=120`), throttles it above 2 GiB of memory
+(`MemoryHigh`) and stops it at 6 GiB (`MemoryMax`). To change the unit without editing the
+packaged file, use a drop-in:
 
 ```bash
 systemctl --user edit proton-drive.service

docs/DEVELOPMENT.md

@@ -31,12 +31,12 @@ time when the installed library has them (`crates/pdfs-gui/src/compat.rs`).
 | Path | Contents |
 |---|---|
 | `crates/pdfs-core` | Shared library: authentication and keyring (`auth`), configuration (`config`), SQLite schema and queries (`db/`), content cache (`cache`), control protocol (`control`), search scoring, sync ignore rules, Google Takeout parsing, machine profile |
-| `crates/pdfs-fuse` | The daemon: FUSE filesystem, read path (`reads`), write queue (`queue`, `drain`, `upload`), sync engine (`sync/`), remote events (`background`), push events for front ends (`events`), control handlers (`control`), photos, devices, supervisor |
+| `crates/pdfs-fuse` | The daemon: FUSE handlers (`filesystem`), the tree (`state`), reads (`reads`), the queue and the drain (`queue`, `drain`, `upload`), link state (`link`), the sync engine (`sync`, `sync/`), moves between locations (`relocate`), remote events (`background`), push events (`events`), control handlers (`control`), photos, devices, the supervisor, and the simulation tests (`sim/`) |
 | `crates/pdfs-cli` | The `pdfs` binary |
 | `crates/pdfs-gui` | `pdfs-app`, `pdfs-tray` and `pdfs-prompt`. Pages in `src/app/pages/`, shared widgets in `src/app/widgets/`, CSS and icons in `resources/` |
 | `po/` | Translation template, catalogs and the scripts that maintain them |
 | `packaging/` | systemd unit, desktop files, icon, PKGBUILD, RPM spec, AUR recipes |
-| `scripts/` | FUSE acceptance suite, map-data generators |
+| `scripts/` | FUSE acceptance suite, map-data generators, the wiki publisher |
 | `docs/` | This documentation |
 
 The GUI talks to the daemon only through the control socket. Anything a front end needs that the
@@ -87,8 +87,9 @@ cargo test --workspace --locked
 scripts/fuse-acceptance.sh --offline-only
 ```
 
-For changes to the FUSE layer, the write queue or the sync engine, also run the live acceptance
+For changes to the FUSE layer, the queue or the sync engine, also run the
-cases described in [TESTING.md](TESTING.md).
+[simulation runs](TESTING.md#simulation-runs), which CI runs only after a push to `main`, and the
+[acceptance suite](TESTING.md#acceptance-suite) on a test account.
 
 For changes to GUI strings, check that every catalog is complete:
 
@@ -136,6 +137,15 @@ file to `po/POTFILES.in`, run `po/update.sh`, and translate the new entries in e
 `#[serde(default)]`, so older files still load, and document it in
 [CONFIGURATION.md](CONFIGURATION.md).
 
+**A bug fix.** Add or update the entry in [BUGS.md](BUGS.md#adding-an-entry), cover the fix with a
+unit test, a simulation scenario or a `regression B<n>` acceptance case, and cite the entry in the
+code as `docs/BUGS.md B<n>`. Do not cite planning notes that are not in the repository.
+
+**A user-visible change.** Update the matching page (user guide, CLI reference, configuration)
+and the `[Unreleased]` section of [CHANGELOG.md](CHANGELOG.md). `scripts/publish-wiki.sh` copies
+the six user pages (`INSTALL`, `USER_GUIDE`, `CLI`, `CONFIGURATION`, `TROUBLESHOOTING`, `RECOVERY`)
+to the GitHub wiki, so keep their file names.
+
 ## Releasing
 
 Releases are cut from `main` by pushing a `v*` tag. `.github/workflows/release.yml` then:
@@ -160,5 +170,5 @@ git tag vX.Y.Z
 git push origin main vX.Y.Z
 ```
 
-Before a release that touches the filesystem or sync, run the managed live mode matrix from
+Before a release, work through [Before a release](TESTING.md#before-a-release). Open
-[TESTING.md](TESTING.md). Open release-assurance items are listed in [ROADMAP.md](ROADMAP.md).
+release-assurance items are listed in [ROADMAP.md](ROADMAP.md#release-assurance).

docs/README.md

@@ -5,7 +5,7 @@
 | Page | What it covers |
 |---|---|
 | [Installation](INSTALL.md) | Packages, building from source, first sign-in, updating and uninstalling |
-| [User guide](USER_GUIDE.md) | My files, available offline, synced folders, conflicts, Photos, sharing, Trash and versions, Computers, the search launcher, the tray |
+| [User guide](USER_GUIDE.md) | My files, available offline, synced folders, sync issues and conflicts, Photos, sharing, Trash and versions, Computers, the search launcher, the tray |
 | [Command-line reference](CLI.md) | Every `pdfs` command, grouped by task, and scripting with `--json` |
 | [Configuration](CONFIGURATION.md) | `config.json`, environment variables, file locations, the systemd service |
 | [Troubleshooting](TROUBLESHOOTING.md) | Diagnosing problems, common symptoms, starting over, reporting a bug |
@@ -16,13 +16,12 @@
 
 | Page | What it covers |
 |---|---|
-| [Development guide](DEVELOPMENT.md) | Building, running and debugging from source; releasing |
+| [Development guide](DEVELOPMENT.md) | Building, running and debugging from source; common changes; releasing |
-| [Architecture](ARCHITECTURE.md) | Crates, read and write paths, sync engine, control protocol, threads, threat model |
+| [Architecture](ARCHITECTURE.md) | Crates, the local tree, read and write paths, the queue, the sync engine, the control protocol, threads, threat model |
-| [Testing](TESTING.md) | Unit tests and the FUSE acceptance suite |
+| [Testing](TESTING.md) | Unit tests, simulation runs and the FUSE acceptance suite |
 | [Translating](TRANSLATING.md) | Adding and updating translations |
 | [Roadmap](ROADMAP.md) | Planned work and verification still owed |
 | [Bug ledger](BUGS.md) | Every tracked defect with its analysis and status |
-| [UI/UX plan](UI_UX_PLAN.md) | Design audit and notes behind the 2.x desktop app |
 
 Also see [CONTRIBUTING.md](../CONTRIBUTING.md) and [SECURITY.md](../SECURITY.md) in the repository
 root.

docs/RECOVERY.md

@@ -133,6 +133,29 @@ pdfs sync restore --device UID
 The folders stay part of the other computer's backup and sync in both directions. This machine
 does not take over that computer's backup.
 
+### Moving another computer's backup here
+
+To switch computers for good, for example from a Windows PC to this Linux machine, move the old
+computer's folders into this computer's backup instead. Use **Move to This Computer…** on that
+computer's row, or:
+
+```bash
+pdfs devices list                 # find the old computer's UID
+pdfs devices migrate UID
+```
+
+Each folder moves on Proton Drive itself, so nothing is uploaded again and no storage is used
+twice. A folder whose name this computer already uses gets the old computer's name added, for
+example `Documents (DESKTOP-1)`. The restore picker then opens, as in
+[Step 3](#step-3-restore-the-folders), so you choose where each folder goes here.
+
+The old computer stays in your account, without those folders. Unlike
+[adoption](#step-2-continue-the-old-computers-backup), this machine keeps its own name and backup.
+
+> [!WARNING]
+> Stop Proton Drive on the old computer first. A client still running there sees its folders
+> disappear, and may upload them again as new.
+
 ## 3. How the restore works
 
 This section is for the curious and for anyone debugging a restore.

docs/ROADMAP.md

@@ -1,24 +1,54 @@
 # Roadmap
 
-Planned work and open verification, as of 2.5.0. Individual defects and their status live in
+Planned work and open verification after 3.0.0. Individual defects and their status are in
-[BUGS.md](BUGS.md), which is the authoritative ledger; this page groups what is left by theme.
+[BUGS.md](BUGS.md); this page groups what is left by theme. Nothing here has a date.
-Nothing here is a promise of a date.
 
+- [Sync engine](#sync-engine)
 - [Data safety and recovery](#data-safety-and-recovery)
 - [Features](#features)
 - [Performance and correctness](#performance-and-correctness)
 - [Verification still owed](#verification-still-owed)
 - [Release assurance](#release-assurance)
 
+## Sync engine
+
+3.0.0 records changes made through the mount locally and sends them from the queue
+([ARCHITECTURE.md §4](ARCHITECTURE.md#4-write-path)). What comes next:
+
+| Item | State | Notes |
+|---|---|---|
+| Remove the online path | Not started | The old way of sending a change inside the syscall, and the `local_first` switch that brings it back, go in the next release |
+| One applier for remote changes | Not started | Everything that comes from Drive (events, listings) changes the tree in one place, which is also the only place that tells the kernel. Replaces today's invalidation helpers and in-memory overlays |
+| Synced folders on the queue | Not started | Mirrored folders feed the local tree and use the same queue as the mount; `sync_entry` becomes the record of the last agreed state. Switching a folder's mode then moves no data except to evict or fetch content |
+| Batch trashes and moves | Deferred | See below |
+| Provisional values as types | Not started | A size or block geometry that is not known yet as its own type, so it cannot reach the kernel as if it were known |
+| Deadlines on every remote call | Partly done | The drain's calls and calls a syscall waits on have one; background calls outside the drain do not yet |
+
+**Batching trashes and moves.** `trash_nodes` and `move_nodes_streaming` take many nodes per call,
+but the queue sends one node per call. It was left out of 3.0.0 on purpose:
+
+- The 3.0.0 speed target is met without it. Making 1,000 files in 100 folders through the mount
+  takes 5.2 s on a LAN profile and 5.0 s on a Wi-Fi profile in the simulation
+  (`PDFS_SIM_MEASURE`, see [TESTING.md](TESTING.md#simulation-runs)).
+- The drain spends its time on creates. Each waits for Drive to list the new node before it
+  counts as landed, and batching does not shorten that.
+- One call answering for many ops has to be split back into results per op. Races in exactly that
+  step were the largest class of bugs found for 3.0.0 (B15x to B17x in [BUGS.md](BUGS.md)).
+
+Before building it, measure `rm -r` of a folder with 1,000 files on Wi-Fi. If that is slow, the
+cheaper fix is to drop the queued trashes of a trashed folder's contents: trashing the folder takes
+them along.
+
 ## Data safety and recovery
 
 | Item | State | Notes |
 |---|---|---|
-| Protect queued changes at shutdown | Not started | A systemd inhibitor lock while `staging/` holds unsent data, a warning when signing out, and a blocking `pdfs sync flush`. Today the queue is visible through `pdfs sync queue`, the tray and **Sync → Overview**, but nothing stops a shutdown (B66) |
+| Protect queued changes at shutdown | Not started | A systemd inhibitor lock while `staging/` holds unsent data, a warning when signing out, and a `pdfs sync flush` that waits for the queue. Today the queue is visible in `pdfs sync queue`, the tray and **Sync → Overview**, but nothing stops a shutdown (B66) |
-| Restore pins from the machine profile | Not started | `profile.json` records pins; `sync restore` does not apply them yet |
+| Restore pins from the machine profile | Not started | `profile.json` records pins; `pdfs sync restore` does not apply them yet |
-| Profile backup health | Not started | A failed profile upload is a `WARN` in the log and nothing in the UI (B68) |
+| Profile backup health | Not started | A failed profile upload is a `WARN` in the log and nothing in the app (B68) |
-| Rotated credentials survive a keyring failure | Open | Surface and retry keyring write failures so a rotated single-use refresh token is not lost (B61) |
+| Rotated credentials survive a keyring failure | Open | Report and retry keyring write failures, so a rotated single-use refresh token is not lost (B61) |
-| Encrypt local state at rest | Not started | SQLCipher for `cache.db` and an AEAD for the content cache, keyed from the keyring. `sdk_cache.db` is already encrypted. See [ARCHITECTURE.md §8](ARCHITECTURE.md#8-threat-model-what-this-client-writes-to-disk-in-plaintext) |
+| Restore never picks a new device silently | Open | Ask when the machine's device is ambiguous after a loss of local state (B67) |
+| Encrypt local state at rest | Not started | SQLCipher for `cache.db` and an AEAD for the content cache, keyed from the keyring. `sdk_cache.db` is already encrypted. See [ARCHITECTURE.md §10](ARCHITECTURE.md#10-threat-model-what-this-client-writes-to-disk-in-plaintext) |
 
 ## Features
 
@@ -26,9 +56,10 @@ Nothing here is a promise of a date.
 |---|---|---|
 | File-manager integration | Not started | Context-menu actions (available offline, share link, versions) and sync badges for Nautilus, Dolphin and Thunar |
 | Terminal UI | Not started | `pdfs tui` with transfers, sync state and logs |
-| Multiple accounts | Not started | Separate config, state and mountpoint per profile, one daemon each |
+| Multiple accounts | Not started | Separate config, state and mountpoint per account, one daemon each |
 | Mount options | Not started | Read-only mount, `allow_other` |
-| Symbolic links | Not started | Proton Drive has no link type; links would need a placeholder format. Until then, creating one fails with `EOPNOTSUPP` |
+| Symbolic links | Not started | Proton Drive has no link type; links would need a placeholder format. Until then, `symlink` fails with `EPERM` |
+| `fsync` that waits for Drive | Idea | `fsync` means "durable locally". A mount option or an xattr could offer "on Drive" without slowing the default |
 | Add someone else's photo to your album | Blocked | Needs `copyPhoto` in the SDK |
 | Photo name search | Not started | Photos search by date and filters only |
 | Automatic photo upload from a folder | Not started | |
@@ -39,34 +70,38 @@ Nothing here is a promise of a date.
 
 | Item | Notes |
 |---|---|
-| Saturating stream-ring accounting | `self.bytes -= …` in `crates/pdfs-fuse/src/reads.rs` should saturate so an accounting drift cannot wrap in release builds |
+| Saturating stream-ring accounting | `self.bytes -= …` in `crates/pdfs-fuse/src/reads.rs` should saturate, so an accounting drift cannot wrap in release builds |
 | Block geometry learned one read late | The first read of a file plans on 4 MiB blocks; accepted as a bounded cost (B87) |
-| Path-based commands under secondary mounts | `pin`, `rename`, `move`, `rm` and sharing cannot name a path inside an on-demand synced folder yet (B88) |
+| Path-based commands under online-only folders | `pin`, `unpin`, opening a file, uploads, sharing and versions cannot name a path inside an online-only synced folder yet. `rm`, `rename`, `mkdir` and `move` can (B88) |
-| Unicode normalization | NFC and NFD names are distinct, deliberately (B36) |
+| Unicode normalization | NFC and NFD names are distinct, on purpose (B36) |
-| Pipelined node enumeration | Faster cold listings of large folders |
+| Pipelined node enumeration | Faster first listings of large folders |
 
 ## Verification still owed
 
-Fixes marked *unverified* in [BUGS.md](BUGS.md) have unit or offline coverage but have not been
+Fixes marked *unverified* in [BUGS.md](BUGS.md) have unit or simulation coverage but have not
-driven against a live account. The larger outstanding runs:
+been driven against a live account. The larger runs still owed:
 
+- **A clean account run on 3.0.0.** The last account run before the release (2026-10-04, on Wi-Fi)
+  failed only its cleanup, on a script bug fixed since. No full run with `--journal-check` has
+  passed on the released code yet.
 - **Disaster-recovery drill.** Register a device, sync a folder, delete all local state, restore
-  with `pdfs sync restore` and compare the tree byte for byte. See [RECOVERY.md](RECOVERY.md).
+  with `pdfs sync restore`, and compare the tree byte for byte. See [RECOVERY.md](RECOVERY.md).
-- **Second-account sharing.** Shared trees on a foreign volume, accepting invitations, changing
+- **Second-account sharing.** Shared folders on a foreign volume, accepting invitations, changing
   roles, the viewer cases of `regression B34`, and an editor writing into someone else's share.
-- **Fault injection.** Network loss mid-upload, a full disk during staging, and crash points
+- **Fault injection on a real account.** Network loss mid-upload, a full disk during staging, and
-  across the write publication path (after each fsync, rename and queue commit).
+  crashes at each step of publishing a write. The simulation covers link loss and restarts against
+  the fake Drive, not a kill at an arbitrary point.
+- **Acceptance runs across a network drop.** A case that spans an outage times out while the queue
+  replays, instead of being reported as interrupted.
 - **CAPTCHA sign-in** against a real verification request (B8).
-- **Managed live mode matrix** before each release:
+- **The overnight hang** (B91) is not diagnosed. The supervisor and `pdfs diagnostics` exist to
-  `scripts/fuse-acceptance.sh --managed-live <empty-a> <empty-b>`. See [TESTING.md](TESTING.md).
+  catch the next one.
-- **The overnight hang** (B91) is not diagnosed yet. The supervisor and `pdfs diagnostics` exist to
-  catch the next occurrence.
 
 ## Release assurance
 
 | Item | State |
 |---|---|
-| Tag, workspace and PKGBUILD version agreement | Enforced by the release workflow |
+| Tag, workspace and PKGBUILD version agree | Enforced by the release workflow |
 | Clean-install test of the `.deb` and `.rpm` in a VM | Pending (B62) |
 | Protocol version identity between front ends and daemon | Open (B63) |
 | SBOM, provenance and checksums for release artifacts | Open (B65). The RPM is GPG-signed |

docs/TESTING.md

@@ -1,303 +1,265 @@
 # Testing
 
-The normal Rust suite exercises the metadata database, sync planner, offline
+Three layers check the client, from fast and offline to slow and against a real account:
-queue, write staging, cache, and FUSE handler state without requiring a Proton
-account:
 
-```console
+| Layer | Needs | Runs in CI |
+|---|---|---|
+| [Unit tests](#unit-tests) | Nothing | Every push and pull request |
+| [Simulation runs](#simulation-runs) | `/dev/fuse` | Every push to `main` |
+| [Acceptance suite](#acceptance-suite) | Nothing for the reference run; a signed-in account for the rest | The reference run only |
+
+## Unit tests
+
+```bash
 cargo test --workspace
 cargo clippy --workspace --all-targets -- -D warnings
 ```
 
-## Filesystem API and live FUSE acceptance suite
+Tests sit in `#[cfg(test)]` modules next to the code. Database tests are in
+`crates/pdfs-core/src/db/tests.rs`; a schema change adds one that migrates from the previous
+version.
 
-The account-free suite exercises the filesystem syscall contract against a
+To check the migrations against a real database, point `PDFS_MIGRATE_DB` at it and run the
-temporary local directory. This validates the runner and covers creation/open
+ignored test. It migrates a copy taken with `VACUUM INTO` and never writes the database named:
-flags, positioned and vectored I/O, truncation and sparse files, `mmap`,
-`sendfile`, `copy_file_range`, durability barriers, namespace/error semantics,
-`renameat2` flags, open-file lifetime, names and enumeration, readdir stability
-under concurrent mutation, metadata updates, extended attributes, allocation and
-punched holes, refusal semantics for unimplemented operations, concurrent I/O,
-and real application workloads. It never reads application state or contacts
-Proton:
 
-```console
+```bash
-scripts/fuse-acceptance.sh --offline-only
+PDFS_MIGRATE_DB=~/.local/state/proton-drive-linux/cache.db \
+  cargo test -p pdfs-core a_copy_of_a_real_database -- --ignored
 ```
 
-Kernel/FUSE behavior and remote convergence need a real mount. With no
+## Simulation runs
-arguments, the script tests the account the running service is logged in to:
 
-```console
+The simulation runs (`crates/pdfs-fuse/src/sim/`) start real daemons with real FUSE mounts against
-scripts/fuse-acceptance.sh           # every case, every mount kind
+an in-memory Drive, `FakeDrive`. The daemon runs as in production (drain workers, sync engine,
-scripts/fuse-acceptance.sh --quick   # one on-demand/mirror pair instead of four
+event feed, online probe, control socket); only its Drive is fake. `FakeDrive` has the faults the
+real one has: listings that lag a create, renames refused for a stale name hash, no atomic
+replace, delayed and reordered events, requests that stall or lose their answer, per-request
+latency, and blocks of uneven size.
+
+A run draws a sequence of steps from a seed: syscalls through a client's mount, the link going
+down and up, restarts, settles (every queue must drain within a budget), and files deleted while
+the drain holds a write to them. Every syscall is checked against an in-memory model of the
+filesystem as it happens. At the end every link comes up and the run checks:
+
+1. **No loss and POSIX.** Drive's copy of each client's folder is what its model says.
+2. **No false conflicts.** No conflict copy anywhere; each file has one writer.
+3. **Convergence.** Each mount shows Drive's tree.
+4. **Liveness.** No syscall took longer than its budget, and every queue drained once the links
+   were up. A call that never returns is caught by a watchdog that writes every thread's stack to
+   `stacks.txt` in the run's state directory.
+
+| Test | Seeds |
+|---|---|
+| `one_client_on_a_good_link` | 12 |
+| `one_client_deleting_files_as_they_upload` | 3 |
+| `one_client_with_stale_hashes_and_reordered_echoes` | 6 |
+| `one_client_on_a_flaky_link` | 4 |
+| `one_client_on_a_slow_link` | 4 |
+| `three_clients_one_writer_each` | 3 |
+
+`sim/daemon.rs` holds scenario tests for single bugs, run the same way.
+
+The tests mount FUSE, so they are ignored by default:
+
+```bash
+cargo test -p pdfs-fuse --lib sim:: -- --ignored --test-threads=1   # what CI runs
+PDFS_SIM_SEEDS=50 cargo test -p pdfs-fuse --lib sim::run -- --ignored --test-threads=1
+PDFS_SIM_SEED=7 RUST_LOG=pdfs_fuse=debug cargo test -p pdfs-fuse --lib \
+  sim::run::tests::one_client_on_a_flaky_link -- --ignored --exact --nocapture
 ```
 
-An account run does this, in order:
+| Variable | Effect |
+|---|---|
+| `PDFS_SIM_SEEDS` | How many seeds each test runs, from 1 |
+| `PDFS_SIM_SEED` | Replay one seed. A failing run prints the seed, the last steps, and where it kept its state |
+| `PDFS_SIM_MEASURE` | Run `a_thousand_files_drain_as_fast_on_wifi_as_on_lan`, which times 1,000 files in 100 folders on a LAN and a Wi-Fi profile and prints the times |
 
-1. Runs the account-free contract as the reference.
+A failure is a seed that can be replayed, but the daemon uses real threads, so a race may need
-2. Runs the contract in a fresh `pdfs-acceptance-<id>` folder in My files and
+several replays. In CI, the `simulation` job uploads the stacks of a hung run as an artifact.
-   diffs it against the reference.
-3. Registers two new sync folders under `~/.cache/pdfs-acceptance/run-<id>/`
-   and runs the contract and the move cases in every on-demand/mirror pairing.
-4. Removes everything it created, locally and remotely, and reports a
-   `cleanup` result. The run fails if anything is left behind.
 
-Cleanup identifies remote folders by uid, never by name alone, so nothing of
+## Acceptance suite
-yours is touched. It removes each sync folder with `sync rm --delete-remote`,
-trashes the My files folder, and then deletes both permanently from the trash.
-It only counts a folder as gone once a fresh trash listing no longer shows it.
-It then reads `pdfs sync queue` and counts any queued op that still names one
-of its folders as left behind too, since such an op keeps its staged bytes and
-retries forever (B102).
-Cleanup also runs on a failure, Ctrl-C, `SIGTERM` or `SIGHUP`. While it runs,
-two more interrupts are ignored; a third abandons it.
 
-Each run records what it is about to create in
+`scripts/fuse-acceptance.sh` checks the filesystem contract a program sees: creation and open
-`~/.cache/pdfs-acceptance/run-<id>/manifest.json` before it creates it, and
+flags, positioned and vectored I/O, truncation and sparse files, `mmap`, `sendfile`,
-holds a lock on that directory. If a run dies without cleaning up (`kill -9`, a
+`copy_file_range`, durability barriers, renames and their `renameat2` flags, open-file lifetime,
-hard timeout, a power cut), the next run finds the unlocked manifest and
+names, `readdir` under concurrent change, metadata, extended attributes, holes, refusals of
-finishes that cleanup first. It then removes stray `pdfs-acceptance-<32 hex>`
+unsupported operations, concurrent I/O, and real application workloads.
-folders that no live run claims: in My files (older than
-`PDFS_ACCEPTANCE_REAP_AGE`, default one hour), under the acceptance home, and
-in the trash. A run does not start while that reap leaves anything behind.
 
-The run creates and destroys real remote folders, so a dedicated test account
+> [!CAUTION]
-without irreplaceable data is still the safest target.
+> Every mode except `--offline-only` creates and deletes real files in Proton Drive. Use a test
+> account with nothing you cannot lose.
 
-`--live PATH...` tests mounts you set up yourself and leaves the sync folder
+### Modes
-configuration alone. It runs destructive POSIX operations only below a fresh
-`pdfs-acceptance-*` directory, refuses paths that are not FUSE mounts, and
-removes its directory on success, failure, or interruption:
 
-```console
+```bash
-scripts/fuse-acceptance.sh --live /mnt/on-demand-testmount
+scripts/fuse-acceptance.sh --offline-only            # the reference run; no account
+scripts/fuse-acceptance.sh                           # the signed-in account, every mode pairing
+scripts/fuse-acceptance.sh --quick                   # one on-demand/mirror pairing instead of four
+scripts/fuse-acceptance.sh --live /mnt/testmount     # mounts you set up yourself
+scripts/fuse-acceptance.sh --managed-live /mnt/a /mnt/b
 ```
 
-### Edge cases and performance
+**The reference run** always runs first, against a temporary local directory. It records the
+facts each case establishes, and every mount is then **compared** against those facts. A case
+fails when the mount differs from an ordinary filesystem, not only when it raises. A fact that may
+legitimately differ (inode numbers, block counts, which optional syscalls exist) is **noted**
+instead, and listed under the target's `accepted` line. The choice is made in the test body, so
+the accepted differences are visible where they are accepted. Prefer `record`; use `note` only
+for something a network filesystem cannot do.
 
-Besides the syscall contract, the suite covers:
+**An account run** (no mode):
 
-- **Block boundaries.** Files of 0 bytes up to two 4 MiB blocks plus 3 bytes,
+1. Runs the reference.
-  including every size next to a boundary, then overwrites that grow, shrink
+2. Runs the contract in a new `pdfs-acceptance-<id>` folder in My files, and at the end reads back
-  and reshape them.
+   a file the run wrote.
-- **Unusual names.** A 255-byte name, NFC and NFD forms of the same text,
+3. Registers two sync folders under `~/.cache/pdfs-acceptance/run-<id>/` and runs the contract and
-  newline, tab, emoji, characters Windows forbids, leading and trailing
+   the move cases in every pairing of on-demand and mirror. Before a folder switches to on-demand,
-  spaces, and a case-only rename.
+   a new file is written into it; once mounted, the file must be listed with its bytes. In every
-- **A deep tree and a wide directory.** 24 levels of nesting renamed at the
+   pairing each folder must still hold the file written into it at setup.
-  top; 128 entries created concurrently, concurrent unlinks, then `rm -rf`.
+4. Removes everything it made, locally and on Drive, and reports `cleanup`. A run that leaves
-  Online, each create is a round trip to the server, and the kernel runs
+   anything behind fails.
-  creates in one directory one at a time. So the wide case gets twice the
-  per-case timeout and notes the time per create as `wide.create_ms`.
-- **Rename patterns.** Swaps, chains, log rotation, replacing a file under an
-  open reader, the `EISDIR`/`ENOTDIR`/`ENOENT` refusals, and a folder moved out
-  and back.
-- **Handle coherency.** Unsynced writes seen by a second handle, two `O_APPEND`
-  writers, 30 rewrite generations, and a truncate under a reader.
-- **Throughput.** 64 MiB written and read sequentially, 1 MiB in 4 KiB writes,
-  and metadata operations on 100 files. The rates are printed. The case fails
-  below `PDFS_ACCEPTANCE_MIN_MIBPS` (default 10) or `PDFS_ACCEPTANCE_MIN_OPS`
-  (default 20 operations per second, or 3 on a FUSE mount, where each create
-  and unlink waits for Drive before it returns).
 
-### The mount is diffed against an ordinary filesystem
+Cleanup finds remote folders by uid, never by name, so nothing of yours is touched. It removes
+each sync folder with `sync rm --delete-remote`, trashes the My files folder, deletes both from
+the trash for good, and checks that a fresh trash listing no longer shows them. Queued ops that
+still name one of its folders count as left behind. Cleanup also runs on a failure, Ctrl-C,
+`SIGTERM` or `SIGHUP`; while it runs, two more interrupts are ignored and a third abandons it.
 
-The local reference run is not only a self-test of the runner. Every case
+Each run writes what it is about to create to `~/.cache/pdfs-acceptance/run-<id>/manifest.json`
-records the facts it established, and a live run is compared against those
+first and holds a lock on that directory. A later run finishes the cleanup of a run that died, and
-recordings, so a case fails when the mount *differs* from an ordinary
+removes stray `pdfs-acceptance-<32 hex>` folders no live run claims: in My files (older than
-filesystem — not only when it raises. The report names the exact key:
+`PDFS_ACCEPTANCE_REAP_AGE`, default one hour), under the acceptance home, and in the trash. It
+does not start while anything is left.
+
+Ops that were queued before the run started are not the run's: it prints one `NOTE` line naming
+them, and its queue waits ignore them.
+
+**`--live PATH...`** runs the contract on mounts you set up, and leaves the sync configuration
+alone. It works only below a new `pdfs-acceptance-*` directory, refuses paths that are not FUSE
+mounts, and removes its directory afterwards. The first path must be a FUSE mount; later paths may
+be another mount or a mirrored folder. If all paths show the **same remote folder**, set
+`PDFS_ACCEPTANCE_CONVERGENCE=1` to also check that bytes written through the first appear through
+the others.
+
+**`--managed-live A B`** takes two existing, empty, unmounted directories, registers them as sync
+folders, and runs every pairing as an account run does, then deletes the remote folders. It
+refuses non-empty paths, mounts, and paths already in `pdfs sync list`.
+
+### Reading the output
+
+A run opens with the mode, the `pdfs` binary and version, Python, the kernel, the per-case limit
+and the options. Each target then names its root, the storage behind it, the daemon and the
+number of cases, followed by one line per case:
 
 ```
-  [DIVERGENCE] live FUSE /mnt/testmount does not match the reference filesystem:
+==> live FUSE /mnt/testmount
-    ! creation and open flags.truncated.size: live=6 reference=0
+  -> root      /mnt/testmount/pdfs-acceptance-…
+  -> storage   FUSE mount /mnt/testmount (fuse.protondrive)
+  -> daemon    pdfs 3.0.0, user@proton.me, online, 0 queued ops
+  -> cases     45 of 45
+  [ 1/45] creation and open flags .................................. ok       0.41s
+  …
+  [21/45] throughput floors ........................................ ok      48.20s
+          write 31 MiB/s, read 54 MiB/s, 4 KiB writes 12.0 MiB/s, metadata 9 ops/s
+  …
+  -> reference matches the ordinary filesystem in 412 compared observations
+  -> result    44 passed, 1 skipped in 11m02s
 ```
 
-Facts are recorded in one of two ways, chosen in the test body:
+A case ends as `ok`, `FAIL`, `TIMEOUT`, `skip` (it does not apply to the target), or `known` (an
+`open B<n>` case reproduced a bug that is still open). Dimmed lines under a case hold its details.
+A failed `regression B<n>` case points to its entry in [BUGS.md](BUGS.md).
 
-- **compared** — a claim about filesystem semantics. The mount must agree.
+The run ends with a table of every target, the report paths, the slowest cases, cases over
-- **noted** — context that legitimately differs: inode numbers, block counts,
+`--budget`, known issues that still reproduce, errors the daemon logged, and each failure. The
-  reported mode bits, and which optional syscalls exist at all. Reported under
+last line is `PASS:` or `FAIL:` with the totals. Colour is used only on a terminal and never with
-  `[capabilities]`, never a failure.
+`NO_COLOR` set.
 
-Because the choice is made at each call site, the set of accepted divergences
+### What the cases cover
-is visible in the test that accepts it. There is no separate allowlist to drift
-out of date. When adding a case, prefer `record`; reach for `note` only when an
-ordinary filesystem can do something a network filesystem genuinely cannot.
 
-### Operations the filesystem does not implement
+Besides the syscall contract:
 
-`git`, `rsync`, `cp -a`, `tar`, `df` and most installers probe for symlinks,
+- **Block boundaries.** Files from 0 bytes to two 4 MiB blocks plus 3 bytes, every size next to a
-hard links, FIFOs, device nodes, `statfs`, file locks, `copy_file_range`,
+  boundary, and overwrites that grow, shrink and reshape them.
-`O_DIRECT` and `SEEK_HOLE` whether or not a filesystem offers them. The suite
+- **Unusual names.** 255 bytes, NFC and NFD forms of the same text, newline, tab, emoji,
-asserts that each either works or is *refused cleanly* — a recognised errno,
+  characters Windows forbids, leading and trailing spaces, a case-only rename.
-never `EIO` and never a hang. A refusal that is merely unimplemented is fine;
+- **A deep tree and a wide folder.** 24 levels renamed at the top; 128 entries created
-one that is dirty breaks software that never asked for the feature.
+  concurrently, unlinked concurrently, then `rm -rf`.
+- **Rename patterns.** Swaps, chains, log rotation, replacing a file under an open reader, the
+  `EISDIR`, `ENOTDIR` and `ENOENT` refusals.
+- **Handle coherency.** Unsaved writes seen by a second handle, two `O_APPEND` writers, 30 rewrite
+  generations, a truncate under a reader.
+- **Throughput.** 64 MiB written and read, 1 MiB in 4 KiB writes, metadata on 100 files. The case
+  fails below `PDFS_ACCEPTANCE_MIN_MIBPS` (default 10) or `PDFS_ACCEPTANCE_MIN_OPS` (default 20
+  operations per second, 3 on a FUSE mount). `0` turns a floor off.
+- **Operations the filesystem does not implement.** `git`, `rsync`, `cp -a`, `tar` and installers
+  probe for symlinks, hard links, FIFOs, device nodes, locks, `O_DIRECT` and `SEEK_HOLE`. Each must
+  work or be refused cleanly: a known errno, never `EIO`, never a hang.
+- **Moves between locations** (`managed` in `--list`). Trees moved between two sync folders in
+  both directions, several sources in one `pdfs move`, and a tree through My files and out again.
+  The refusals must move nothing and lose nothing: a name already taken, a folder into itself, a
+  mirrored source holding something Drive lacks, a file still open for writing.
+- **The CLI.** `pdfs` into a closed pipe exits 0 with nothing on stderr; `pdfs mkdir`, `rename`
+  and `rm` by local path, and their refusals.
 
-### Regressions from the bug ledger
+### Regressions and open bugs
 
-Cases named `regression B<n>` reproduce a bug from `docs/BUGS.md` so it stays
+A case named `regression B<n>` reproduces an entry of [BUGS.md](BUGS.md) so it stays fixed. Most
-fixed. B69 (identical rewrite must not fork a `(sync-conflict …)` copy), B70 (an
+need a live mount and a reachable daemon, and are skipped without one. `--list` prints every case
-in-flight `.crdownload` must not be sealed as a revision) and B74 (a file
+and the targets it runs on.
-renamed after close must keep its content) need a real mount and a reachable
-daemon; they are skipped, not failed, without one.
 
-**B100** (a copied tree reads back at its exact sizes) copies 48 files of
+A regression case checks the outcome **on Drive**, so it waits for the queue first. Reading back
-assorted sizes into the mount at once, as `cp -r` does. On a live mount it
+through the mount proves nothing: the local caches return the bytes just written whether or not
-waits for the queue, checks every size and byte, runs `pdfs refresh` on each
+they reached Drive. A write is queued when the kernel releases the file, after `close(2)` has
-folder to drop the cached listing, and checks again. The refresh is what
+returned, so a case that reads `pdfs sync queue` right after writing waits for the ops it expects.
-brought back the provisional sizes the bug reported.
 
-**B101** (a write during its create's upload reaches Drive) holds new files open for
+A case named `open B<n>` checks a bug that is still open. While it reproduces, the case ends as
-different times before writing, so their empty creates land before, during and after the
+`known`: listed at the end, but not a failure. When it passes, the bug is fixed: rename the case to
-bytes arrive, then checks every file after the queue drains.
+`regression B<n>` and make it fail with `check`. No case is open at the moment.
 
-B74 was found by exactly this mechanism: the B70 case failed, and narrowing it
+Some cases need what a test account cannot provide alone and skip without it: B34 needs a folder
-produced a smaller reproduction that got its own case. The defect is fixed and
+shared read-only by a **second account**, B34b one shared with editor rights, and B79 an on-demand
-live-validated (2026-07-26); the case now guards against its return.
+synced folder.
 
-**B79** (an on-demand device folder accepts writes) discovers its target from
+### Timeouts, reports and hung mounts
-`pdfs locations --json` and skips when this machine has no mounted on-demand
-folder. It is the cheap standing guard against a *cross-mount* permission
-regression: the primary mount holds device-folder nodes too, and the queue guard
-intersects what every live inode space says about a uid, so a fail-closed
-classification in one mount denies writes in another.
 
-**B34** (a viewer-role share is read-only) and **B34b** (an editor-role share
+A hung FUSE call cannot be interrupted from Python. Each case runs under a soft alarm (`--timeout`,
-still writes) locate their subject through `pdfs shared-with-me --json`, which
+default 180 s, or `PDFS_ACCEPTANCE_TIMEOUT`) that reports the case and lets cleanup run, backed by
-now carries `role` and a mount-relative `path`. Both skip when the account has no
+a hard stop that dumps every thread's stack and exits. After a timeout the run checks whether the
-accepted share at that role — B34 needs a **second account** to have shared a
+mount still answers a `stat` and a listing within 15 s. If it does, the target goes on; if not, its
-folder read-only, which is the one part of the sharing suite that cannot be
+remaining cases are skipped. Cases that make many round trips by design get twice the limit.
-self-served. B34b degrades gracefully in the other direction: a shared *file*
-gets its mode bits and `W_OK` checked but is never written to, because it is
-someone else's document.
 
-B34's fourth assertion is the load-bearing one: `pending_uploads` and
+| Option | Effect |
-`pending_changes` must be **unchanged** across the refused writes. Mode bits
+|---|---|
-alone would pass a fix that still admitted the write into `pending_op`, which is
+| `--report-json PATH` | Every result and recorded observation. Attach it to a bug report |
-the actual harm — a background drain failing 403 forever.
+| `--report-junit PATH` | JUnit XML. `known` is reported as skipped |
-
+| `--budget SECONDS` | Flags cases that pass but take longer (`PDFS_ACCEPTANCE_BUDGET`) |
-**Synthetic `Shared with me/` directory contract** asserts the virtual directory
+| `--journal-check` | Fails the run if `proton-drive.service` logged an error during it, or the warnings "queued write conflicts; keeping a conflict copy" and "a fuse worker has held the same job for a long time" |
-enumerates, reports `0555`, and refuses `mkdir`/`rmdir`/`rename`. It skips when
+| `--durability` | Restarts the service mid-suite and checks the bytes written before it. Proves the queue survives a restart. `PDFS_ACCEPTANCE_UNIT` names another unit |
-the directory is absent (an account with no accepted shares).
+| `--fail-fast` | Stops at the first failure |
-
+| `--list` | Prints every case and its targets |
-A regression case asserts against the *remote* outcome, so it must wait for the
-queue to drain before reading. Reading straight back through the mount proves
-nothing: the local attribute and content caches will happily return the bytes
-that were just written even when nothing reached Drive, which is precisely how
-B74 stayed invisible.
-
-### Timeouts, reports, and hung mounts
-
-A wedged FUSE operation cannot be interrupted from Python, so each case runs
-under a soft alarm (`--timeout`, default 180s) that reports the case and lets
-cleanup run, backed by a hard stop that dumps every thread's stack and exits.
-That backstop is the only way to learn *where* a mount hung. A timeout ends the
-run: later cases against a wedged mount produce noise, not information.
-
-```console
-scripts/fuse-acceptance.sh --live /mnt/testmount \
-  --timeout 300 --report-junit results.xml --budget 30
-```
-
-`--report-json` also writes every recorded observation, which is what to attach
-to a bug report. `--budget SECONDS` flags cases that pass but got slower —
-B5 was a 186 ms-per-call regression that a pass/fail suite could not see.
-`--list` prints every case and which targets it runs against, and `--fail-fast`
-stops at the first failure.
-
-`--journal-check` fails the run if `proton-drive.service` logged any error while
-it ran. A suite can pass every assertion while the daemon logs failures behind
-it; that has happened, and it was caught only by reading the journal by hand.
-
-With `--live`, abandoned `pdfs-acceptance-*` roots from a crashed run are
-removed at startup, but only if they match the exact generated name and are
-over an hour old (`PDFS_ACCEPTANCE_REAP_AGE`), so a concurrent run is never
-disturbed. An account run instead uses the manifest and reaper described
-above.
-
-### Automated mode matrix
-
-An account run drives this matrix itself, in folders it creates. To use
-directories of your choice instead, the managed live runner accepts two
-existing, empty, unmounted directories. It
-registers both as new sync folders, waits for initial synchronization, then
-tests all four pairs in order: on-demand/on-demand, on-demand/mirror,
-mirror/on-demand, and mirror/mirror. Every transition must become idle, and an
-on-demand folder must actually appear as a mount before its contract runs.
-
-```console
-mkdir -p /mnt/pdfs-test-a /mnt/pdfs-test-b
-scripts/fuse-acceptance.sh --managed-live /mnt/pdfs-test-a /mnt/pdfs-test-b
-```
-
-This creates remote folders and permanently deletes those test remotes during
-cleanup. It refuses non-empty paths, existing mounts, and paths already present
-in `pdfs sync list`. Use `PDFS_ACCEPTANCE_SYNC_TIMEOUT` to extend transition
-timeouts and `PDFS_ACCEPTANCE_PDFS` to select a non-installed CLI binary, for
-example `target/debug/pdfs`.
-
-After the contract, each mode pair also runs the move cases (`--list` shows
-them as `managed`). They move trees between the two folders in both
-directions, move several sources in one `pdfs move`, and pass a tree through
-My files and out again. Every case waits for Drive before and after the move.
-It then checks that the tree is only at the destination, that every byte
-arrived, and that neither side made conflict copies. The refusal cases prove
-that nothing moves and nothing is lost when:
-
-- the destination already has the name;
-- a folder would move into itself;
-- a mirror source holds something Drive lacks (a symlink);
-- a file in an on-demand source is still open for writing.
-
-The My files case writes a test folder into your real My files and removes it
-afterwards. It skips when the daemon reports no My files mount, or when the
-locations are on different volumes.
-
-### Durability drill
-
-`--durability` restarts `proton-drive.service` in the middle of the suite and
-re-verifies the bytes written before it. `staging/` and `recovery/` can hold the
-only copy of a file whose upload has not finished, so this is the case that
-proves the queue is persistent rather than in-memory. It is opt-in because it
-interrupts a running daemon; `PDFS_ACCEPTANCE_UNIT` selects a different unit.
 
 ### Selecting cases
 
-During development, `PDFS_ACCEPTANCE_ONLY` runs tests whose descriptive name
+`PDFS_ACCEPTANCE_ONLY` runs the cases whose name contains the text, ignoring case. Separate several
-contains the supplied text (for example `PDFS_ACCEPTANCE_ONLY=namespace`). A
+with commas (`PDFS_ACCEPTANCE_ONLY=B116,B117`). A filter that matches no case at all fails, as the
-release acceptance run must leave it unset so the complete contract executes.
+typo it is. A release run leaves it unset.
 
-A filter naming a live-only case (every `regression B<n>` is one) selects nothing
+| Variable | Effect |
-in the account-free reference run, which is not an error — that target simply has
+|---|---|
-nothing to do. Only a filter matching *no case at all* fails, as the typo it is.
+| `PDFS_ACCEPTANCE_PDFS` | The `pdfs` binary to use, for example `target/debug/pdfs` |
+| `PDFS_ACCEPTANCE_SYNC_TIMEOUT` | Seconds a sync folder may take to settle after a change of mode |
+| `PDFS_ACCEPTANCE_REAP_AGE` | Age in seconds after which a stray `pdfs-acceptance-*` folder is removed (default 3600) |
+| `PDFS_ACCEPTANCE_CONVERGENCE` | `1` checks that several `--live` paths show the same bytes |
+| `PDFS_ACCEPTANCE_MIN_MIBPS`, `PDFS_ACCEPTANCE_MIN_OPS` | Throughput floors |
+| `PDFS_ACCEPTANCE_UNIT` | The systemd unit `--durability` restarts |
 
-Passing more paths runs the same filesystem suite independently against each.
+## Before a release
-The first path must be the FUSE mount under test; later paths may be another
-FUSE mount or a normal local mirror filesystem:
 
-```console
+1. The quality gates and the simulation runs pass in CI.
-PDFS_ACCEPTANCE_SYNC_TIMEOUT=180 \
+2. A full account run with `--journal-check` passes on a test account:
-  scripts/fuse-acceptance.sh --live /mnt/on-demand-testmount /mnt/testmount
+   `scripts/fuse-acceptance.sh --journal-check`.
-```
+3. Fixes marked *unverified* in [BUGS.md](BUGS.md) that a run now covers are marked verified.
 
-If two paths really are views of the **same remote folder**, enable an
+What no automated run covers yet is listed under
-additional byte-for-byte convergence check explicitly:
+[Verification still owed](ROADMAP.md#verification-still-owed).
-
-```console
-PDFS_ACCEPTANCE_CONVERGENCE=1 \
-  scripts/fuse-acceptance.sh --live /mnt/first-view /mnt/second-view
-```
-
-Do not enable that flag merely because two sync folders belong to the same
-account. Their configured remote UIDs must be identical.
-
-Normally the live suite applies the same API contract independently to each
-supplied mount. In convergence mode it exercises the primary once and verifies
-that the resulting bytes appear through every secondary view. A pass is
-strong evidence for those paths, not a blanket data-loss guarantee. Before a
-release, also run the recovery drills in `docs/RECOVERY.md` and inspect
-`docs/BUGS.md` for live-verification items.
-
-The runner accepts already-mounted paths instead of starting a daemon. This
-keeps authentication and keyring setup explicit and prevents it from silently
-reusing or replacing the normal application state directory.