fix(fuse): keep pinned files on disk through remote changes

A remote change to a pinned file called `ContentCache::evict`, which does
not check pins, and only the pin request itself ever downloaded anything.
An edit from another device, or even a rename, left the file listed as kept
offline with no copy, so the next read downloaded it or failed without a
network. A file added to a pinned folder elsewhere was never downloaded,
and a folder pin whose downloads failed while offline never retried them.

A remote change no longer evicts a pinned file's copy. The copy is checked
against the revision's (mtime, size), so a newer revision does not read
it, and a rename keeps the mtime (B123), so the copy stays valid. A new
pdfs-pin-keeper thread checks pins again and downloads files that are
missing or stale:

- the pins a batch of remote events changed, after the batch's listings
  are dropped, including a pinned folder that gets a new file;
- every pin at startup, when the link returns, and after the event feed
  loses continuity;
- a file whose version is restored.

Failed downloads retry with a backoff of 30 s to 30 min. Pinning and the
keeper settle a provisional size first: a copy stored under the
ciphertext size never matched the plaintext it holds.

Fixes B282.

Cargo.lock

@@ -3541,7 +3541,7 @@ checksum = "2ee67f1008b1ba2321834326597b8e186293b049a023cdef258527550b9935b4"
 
 [[package]]
 name = "pdfs-cli"
-version = "3.7.0"
+version = "3.8.0"
 dependencies = [
  "anyhow",
  "clap",
@@ -3558,11 +3558,10 @@ dependencies = [
 
 [[package]]
 name = "pdfs-core"
-version = "3.7.0"
+version = "3.8.0"
 dependencies = [
  "async-trait",
  "base64 0.23.1",
- "chrono",
  "dbus-secret-service-keyring-store",
  "directories",
  "ignore",
@@ -3586,7 +3585,7 @@ dependencies = [
 
 [[package]]
 name = "pdfs-fuse"
-version = "3.7.0"
+version = "3.8.0"
 dependencies = [
  "async-trait",
  "base64 0.23.1",
@@ -3608,7 +3607,7 @@ dependencies = [
 
 [[package]]
 name = "pdfs-gui"
-version = "3.7.0"
+version = "3.8.0"
 dependencies = [
  "anyhow",
  "async-channel",
@@ -3848,14 +3847,13 @@ dependencies = [
 
 [[package]]
 name = "proton-drive-rs"
-version = "0.11.0"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "14a22e621abbc1c61b4640728a7de969c16b66d5d983b59c638d501fda25a7b9"
+checksum = "a8fa2a88130883010b32035e208aaa36fb275f6d7d78ed44a1069b1d33d24481"
 dependencies = [
  "async-trait",
  "base64 0.23.1",
  "bytes",
- "chrono",
  "futures",
  "getrandom 0.4.3",
  "hex",
@@ -3876,9 +3874,9 @@ dependencies = [
 
 [[package]]
 name = "proton-sdk"
-version = "0.11.0"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bd55a5e8b6600f3aa282ebbdf13ff366431ff9aae84d4eb20b0ef06d598919fe"
+checksum = "af0bf8d50fa829d1a65b09c6855b606578d02734d4089874c971d1063c23c353"
 dependencies = [
  "aes-gcm 0.11.1",
  "async-trait",

Cargo.toml

@@ -3,7 +3,7 @@ resolver = "2"
 members = ["crates/pdfs-core", "crates/pdfs-fuse", "crates/pdfs-cli", "crates/pdfs-gui"]
 
 [workspace.package]
-version = "3.7.0"
+version = "3.8.0"
 edition = "2024"
 license = "MIT"
 authors = ["Nils Pukropp <contact@narl.io>"]
@@ -15,9 +15,8 @@ keywords = ["proton", "drive", "fuse", "sync", "linux"]
 categories = ["filesystem", "command-line-utilities"]
 
 [workspace.dependencies]
-proton-sdk = { version = "0.11.0" }
-proton-drive-rs = { version = "0.11.0" }
-chrono = { version = "0.4", default-features = false, features = ["std"] }
+proton-sdk = { version = "0.10.1" }
+proton-drive-rs = { version = "0.10.1" }
 
 # Internal crates.
 pdfs-core = { path = "crates/pdfs-core" }

crates/pdfs-core/Cargo.toml

@@ -12,7 +12,6 @@ description = "Core auth/session/config for the Proton Drive Linux client"
 [dependencies]
 proton-sdk.workspace = true
 proton-drive-rs.workspace = true
-chrono.workspace = true
 tokio.workspace = true
 serde.workspace = true
 serde_json.workspace = true

crates/pdfs-core/src/lib.rs

@@ -29,7 +29,6 @@ pub mod similar;
 pub mod syncignore;
 pub mod syncroot;
 pub mod takeout;
-pub mod timestamp;
 pub mod tray;
 pub mod update;
 

crates/pdfs-core/src/timestamp.rs

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

crates/pdfs-fuse/src/background.rs

@@ -157,6 +157,17 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
             if ours {
                 debug!(uid = %node_uid, "ignoring remote event for a node with a queued write");
             }
+            // A file kept offline keeps its copy through a change, and the
+            // keeper replaces it once this batch's listings are read again.
+            // The copy is checked against the revision's `(mtime, size)`, so
+            // no read takes it for a newer revision. Evicted, it was gone until
+            // something read the file, which then downloaded it (B282). A
+            // node new in, or moved into, a kept folder is fetched by checking
+            // that folder.
+            let kept = match !*is_trashed && !ours {
+                true => kept_by_pin(core, node_uid, parent_node_uid.as_ref()),
+                false => None,
+            };
             let mut had_node = false;
             core.for_each_mount(|st, notify| {
                 if *is_trashed {
@@ -172,9 +183,12 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
                 }
             });
             // Once, not once per mount: the content cache is per-daemon.
-            if had_node {
+            if had_node && kept.is_none() {
                 core.cache.evict(node_uid);
             }
+            if let Some(kept) = kept {
+                dirty.kept.insert(kept);
+            }
             // A create, rename or move-in shows up as a change to the parent
             // listing too, which is recorded for the end of the batch rather
             // than acted on here — see [`DirtyParents`].
@@ -205,6 +219,8 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
         | DriveEvent::ScopeAccessLost { .. }
         | DriveEvent::SharedWithMeUpdated { .. } => {
             warn!("event access continuity lost; downgrading shared trees and resyncing lazily");
+            // Changes went by unseen, kept files among them (B282).
+            core.recheck_all_pins();
             apply_result = apply_result.and(core.db.clear_state(SHARED_WITH_ME_SYNCED_MS));
             core.for_each_mount(|st, notify| {
                 let dirs: Vec<u64> = st.children.keys().copied().collect();
@@ -296,6 +312,21 @@ struct DirtyParents {
     /// Checked per mount — a mount that already lists every one of those
     /// children under that parent keeps its listing.
     ours: HashMap<NodeUid, HashSet<NodeUid>>,
+    /// Pinned files and folders the batch changed, for the pin keeper to
+    /// check once the listings above are dropped (`keeper`).
+    kept: HashSet<NodeUid>,
+}
+
+/// What the pin keeper has to check after a remote change to `node_uid`,
+/// whose parent is now `parent_uid`: the node itself when a pin keeps it, or
+/// else the parent, when a pinned folder holds it and the node is new there.
+fn kept_by_pin(core: &Core, node_uid: &NodeUid, parent_uid: Option<&NodeUid>) -> Option<NodeUid> {
+    if core.cache.is_pinned(node_uid) {
+        return Some(node_uid.clone());
+    }
+    parent_uid
+        .filter(|parent| core.cache.is_pinned(parent))
+        .cloned()
 }
 
 /// Whether this mount's cached listing of `parent_uid` already accounts for
@@ -476,6 +507,9 @@ pub(super) async fn run_event_sync(
             cursor = Some(applied);
         }
         flush_dirty_parents(&core, &dirty);
+        for uid in &dirty.kept {
+            core.recheck_pinned(uid);
+        }
         // Another device changed the tree: whatever a front-end lists may have
         // moved, including what is shared and what is in the trash.
         core.events

crates/pdfs-fuse/src/control.rs

@@ -204,18 +204,42 @@ fn route_to_mount(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Cor
 /// B99), so resolving one needs this too. A mirror folder has no mount to run
 /// against: a file there is an ordinary local file.
 fn route_change(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core, PathBuf)> {
+    route_within(core, mountpoint, path, |path| {
+        format!("{path} is in a mirrored folder; change the local file there instead")
+    })
+}
+
+/// [`route_to_mount`] for keeping a node offline or releasing it. A file in an
+/// on-demand synced folder is a different Drive node from any file of the
+/// same name under the primary mount, and keeping one offline did nothing for
+/// the other: a program reading the synced folder's copy downloaded it
+/// (`docs/BUGS.md` B281). A mirror folder already holds every file on disk.
+fn route_keep(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core, PathBuf)> {
+    route_within(core, mountpoint, path, |path| {
+        format!(
+            "{path} is in a mirrored folder, which keeps all its files on this computer already"
+        )
+    })
+}
+
+/// [`route_to_mount`], refusing a path that leaves the mount it routed to and
+/// answering a path in a mirror folder, which has no mount, with `mirrored`.
+fn route_within(
+    core: &Core,
+    mountpoint: &Path,
+    path: &str,
+    mirrored: impl FnOnce(&str) -> String,
+) -> CoreResult<(Core, PathBuf)> {
     let routed = route_to_mount(core, mountpoint, path).map_err(|e| {
         let p = Path::new(path);
-        let mirrored = core
+        let in_mirror = core
             .db
             .sync_folder_list()
             .unwrap_or_default()
             .iter()
             .any(|folder| folder.mode == "mirror" && p.starts_with(&folder.local_path));
-        if mirrored {
-            CoreError::invalid(format!(
-                "{path} is in a mirrored folder; change the local file there instead"
-            ))
+        if in_mirror {
+            CoreError::invalid(mirrored(path))
         } else {
             e
         }
@@ -231,6 +255,18 @@ fn route_change(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core,
     }
 }
 
+/// The path the pin registry keeps for a pin made through `routed`: the
+/// mount-relative path on the primary mount, as it always was, and the
+/// absolute path the request named on an on-demand folder's mount, since
+/// that node is not under the primary mountpoint (`docs/BUGS.md` B281).
+fn pin_record(routed: &Core, rel: &Path, path: &str) -> PathBuf {
+    if routed.primary {
+        rel.to_path_buf()
+    } else {
+        Path::new(path).components().collect()
+    }
+}
+
 /// [`route_change`] for a request that trashes or renames the node it names.
 /// A mount's root is My files or a whole synced folder. An on-demand folder's
 /// root has a parent on Drive, so nothing further down would stop `pdfs rm
@@ -521,8 +557,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
         Ok(CtlRequest::Subscribe) => {
             CtlResponse::error(CoreError::invalid("a subscription is served on its own"))
         }
-        Ok(CtlRequest::Pin { path }) => match rel_to_mount(mountpoint, &path) {
-            Ok(rel) => match core.pin(&rel) {
+        Ok(CtlRequest::Pin { path }) => match route_keep(core, mountpoint, &path) {
+            Ok((routed, rel)) => match routed.pin(&rel, &pin_record(&routed, &rel, &path)) {
                 Ok(name) => {
                     core.touch_profile();
                     CtlResponse::Ok {
@@ -533,8 +569,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             },
             Err(e) => CtlResponse::error(e),
         },
-        Ok(CtlRequest::Unpin { path }) => match rel_to_mount(mountpoint, &path) {
-            Ok(rel) => match core.unpin(&rel) {
+        Ok(CtlRequest::Unpin { path }) => match route_keep(core, mountpoint, &path) {
+            Ok((routed, rel)) => match routed.unpin(&rel) {
                 Ok(name) => {
                     core.touch_profile();
                     CtlResponse::Ok {
@@ -939,8 +975,6 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                     });
                     let metadata = proton_drive_rs::PhotoUploadMetadata {
                         capture_time,
-                        last_modification_time: capture_time
-                            .and_then(pdfs_core::timestamp::modification_time),
                         ..Default::default()
                     };
                     let thumbnails = core.upload_thumbnails(Path::new(&source_path), &name);

crates/pdfs-fuse/src/drive.rs

@@ -352,13 +352,7 @@ impl DriveApi for ProtonDriveClient {
         name: &str,
         last_modification_time: Option<i64>,
     ) -> Result<NodeUid> {
-        ProtonDriveClient::create_folder(
-            self,
-            parent_uid,
-            name,
-            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
-        )
-        .await
+        ProtonDriveClient::create_folder(self, parent_uid, name, last_modification_time).await
     }
 
     async fn upload_file(
@@ -390,7 +384,7 @@ impl DriveApi for ProtonDriveClient {
             reader,
             intended_size,
             thumbnails,
-            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
+            last_modification_time,
             aead,
         )
         .await
@@ -415,7 +409,7 @@ impl DriveApi for ProtonDriveClient {
             reader,
             intended_size,
             thumbnails,
-            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
+            last_modification_time,
             aead,
         )
         .await
@@ -435,7 +429,7 @@ impl DriveApi for ProtonDriveClient {
             reader,
             intended_size,
             thumbnails,
-            last_modification_time.and_then(pdfs_core::timestamp::modification_time),
+            last_modification_time,
         )
         .await
     }

crates/pdfs-fuse/src/keeper.rs

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

crates/pdfs-fuse/src/lib.rs

@@ -91,6 +91,7 @@ mod drive;
 use drive::{DriveApi, RevisionRead};
 mod events;
 mod filesystem;
+mod keeper;
 mod link;
 pub use filesystem::ProtonFs;
 mod mount;
@@ -589,6 +590,8 @@ struct Core {
     /// Nudges the drain workers: set true and notify to have them re-examine
     /// the queue instead of waiting out their backoff.
     drain_wake: Arc<(Mutex<bool>, Condvar)>,
+    /// The pins the keeper owes a check (`keeper`).
+    pin_work: Arc<Mutex<keeper::PinWork>>,
     /// The daemon's stop signal, shared with every background loop this `Core`
     /// was cloned into so teardown can end and join them (`docs/BUGS.md` B44).
     shutdown: Arc<shutdown::Shutdown>,
@@ -4270,7 +4273,12 @@ impl Core {
     /// recursive pin and downloads every descendant file on a background thread,
     /// reported as a job: a big folder far outlasts the socket read timeout.
     /// Returns a human message.
-    fn pin(&self, rel: &Path) -> CoreResult<String> {
+    ///
+    /// `recorded` is the path the pin registry keeps for the front ends to
+    /// open the pin by: `rel` itself on the primary mount, which they join to
+    /// the mountpoint, and the absolute local path on an on-demand folder's
+    /// mount, whose node is not reachable under the primary mountpoint at all.
+    fn pin(&self, rel: &Path, recorded: &Path) -> CoreResult<String> {
         let (ino, uid) = self.resolve(rel)?;
         let (name, is_folder, mtime, size) = {
             let st = self.state();
@@ -4294,7 +4302,7 @@ impl Core {
             // Record the recursive pin first so every descendant is eviction-
             // exempt before we start filling the cache with the subtree.
             self.cache
-                .add_pin(&uid, rel, true)
+                .add_pin(&uid, recorded, true)
                 .map_err(|e| CoreError::from_api(&e, "pin"))?;
             let core = self.clone();
             let folder = name.clone();
@@ -4304,9 +4312,15 @@ impl Core {
                 .map_err(|e| CoreError::internal(format!("spawn pin: {e}")))?;
             return Ok(format!("{name}: downloading its files in the background"));
         }
+        // Stored under a provisional size, the copy would never match the
+        // plaintext it holds (`docs/BUGS.md` B282).
+        let size = match self.kept_file(ino) {
+            Some(file) if file.uid == uid => file.size,
+            _ => size,
+        };
         self.fetch_content(&uid, &name, mtime, size)?;
         self.cache
-            .add_pin(&uid, rel, false)
+            .add_pin(&uid, recorded, false)
             .map_err(|e| CoreError::from_api(&e, "pin"))?;
         Ok(name)
     }
@@ -4324,14 +4338,20 @@ impl Core {
             Ok(files) => {
                 job.set_total(files.len() as u64);
                 let mut failed = 0usize;
-                for (uid, file, mtime, size) in files {
+                for ino in files {
                     if self.shutdown.is_stopping() || !self.cache.is_pinned(folder) {
                         return;
                     }
-                    job.detail(file.clone());
-                    if let Err(e) = self.fetch_pinned(&uid, &file, mtime, size) {
-                        warn!(%uid, error = %e, "pin folder: download failed");
-                        failed += 1;
+                    // A file with a queued write, or no readable size, is
+                    // left to the drain and the keeper (`keeper::kept_file`).
+                    if let Some(file) = self.kept_file(ino) {
+                        job.detail(file.name.clone());
+                        if let Err(e) =
+                            self.fetch_pinned(&file.uid, &file.name, file.mtime, file.size)
+                        {
+                            warn!(uid = %file.uid, error = %e, "pin folder: download failed");
+                            failed += 1;
+                        }
                     }
                     job.step();
                 }
@@ -4365,9 +4385,9 @@ impl Core {
         Ok(())
     }
 
-    /// Every file in the subtree rooted at folder `ino`.
-    fn pin_subtree_files(&self, ino: u64) -> CoreResult<Vec<(NodeUid, String, i64, u64)>> {
-        let mut files: Vec<(NodeUid, String, i64, u64)> = Vec::new();
+    /// The inode of every file in the subtree rooted at folder `ino`.
+    fn pin_subtree_files(&self, ino: u64) -> CoreResult<Vec<u64>> {
+        let mut files: Vec<u64> = Vec::new();
         let mut stack = vec![ino];
         while let Some(dir) = stack.pop() {
             if self.shutdown.is_stopping() {
@@ -4382,12 +4402,7 @@ impl Core {
                         if e.node.is_folder() {
                             stack.push(k);
                         } else {
-                            files.push((
-                                e.uid.clone(),
-                                e.node.name.clone(),
-                                e.node.modification_time,
-                                node_size(&e.node),
-                            ));
+                            files.push(k);
                         }
                     }
                 }

crates/pdfs-fuse/src/link.rs

@@ -286,6 +286,9 @@ impl Core {
             warn!(error = %e, "moving backed-off ops up after a reconnect failed");
         }
         self.wake_drain();
+        // Downloads for pins failed while the link was down, and the events
+        // that would have named the files are behind us (`docs/BUGS.md` B282).
+        self.recheck_all_pins();
     }
 
     /// Wait up to `budget` for the link to come back. Returns whether it is up.

crates/pdfs-fuse/src/mount.rs

@@ -511,6 +511,7 @@ pub(crate) fn mount_with(
         landed: Arc::new(Mutex::new(HashMap::new())),
         unadopted: Arc::new(Mutex::new(HashMap::new())),
         drain_wake: Arc::new((Mutex::new(false), Condvar::new())),
+        pin_work: Arc::new(Mutex::new(Default::default())),
         shutdown: Arc::new(crate::shutdown::Shutdown::default()),
         upload_times: Arc::new(Mutex::new(HashMap::new())),
         upload_cancel: Arc::new(Mutex::new(HashMap::new())),
@@ -621,6 +622,17 @@ pub(crate) fn mount_with(
         keep_or_abandon(&core, control_socket, &mut workers, spawned)?;
     }
 
+    // Keep pinned files on this computer through changes made elsewhere, and
+    // fetch the ones a failed or missed download left out (`docs/BUGS.md`
+    // B282). Its own thread: a check lists folders and downloads files.
+    {
+        let keeper_core = core.clone();
+        let spawned = std::thread::Builder::new()
+            .name("pdfs-pin-keeper".into())
+            .spawn(move || keeper_core.run_pin_keeper());
+        keep_or_abandon(&core, control_socket, &mut workers, spawned)?;
+    }
+
     // Keep the launcher prompt's "This computer" index fresh. Its own thread:
     // the walk is I/O-heavy and must never sit in front of a FUSE callback.
     if matches!(host, Host::Daemon) {

crates/pdfs-fuse/src/redate.rs

@@ -200,7 +200,6 @@ impl Core {
         let reader = CountingReader::new(std::io::BufReader::new(file), &guard);
         let metadata = PhotoUploadMetadata {
             capture_time: Some(candidate.wanted),
-            last_modification_time: pdfs_core::timestamp::modification_time(candidate.wanted),
             ..Default::default()
         };
         let uploaded = self.rt.block_on(photos.upload_photo_from(

crates/pdfs-fuse/src/revisions.rs

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

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

@@ -3447,6 +3447,118 @@ mod tests {
         let _ = std::fs::remove_dir_all(&dir);
     }
 
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse sim:: -- --ignored`"]
+    fn pinning_a_file_in_an_on_demand_folder_keeps_that_folders_copy() {
+        // Keeping a file offline took only paths under the primary mount, so
+        // the copy in an on-demand synced folder could not be kept, and a
+        // program reading it there downloaded it every time (B281).
+        let drive = FakeDrive::new();
+        let dir = scratch("pin-in-ondemand");
+        let daemon = Daemon::start(&dir, drive.client(1, Faults::lan())).unwrap();
+        let ondemand = dir.join("ondemand");
+        sync_folder(&daemon, &ondemand, "ondemand");
+
+        let content = b"not a real png, but kept all the same".repeat(64);
+        let file = ondemand.join("photo.png");
+        std::fs::write(&file, &content).unwrap();
+        assert!(wait_until(Duration::from_secs(30), || {
+            daemon.pending().is_ok_and(|items| items.is_empty())
+        }));
+        daemon.request(&Request::PurgeCache).unwrap();
+
+        let path = file.canonicalize().unwrap().to_string_lossy().into_owned();
+        let pinned = daemon
+            .request(&Request::Pin { path: path.clone() })
+            .unwrap();
+        assert!(matches!(pinned, Response::Ok { .. }), "{pinned:?}");
+        let pins = || match daemon.request(&Request::ListPins) {
+            Ok(Response::Pins { pins }) => pins,
+            other => panic!("pins: {other:?}"),
+        };
+        let listed = pins();
+        assert!(
+            listed.iter().any(|pin| pin.path == path && pin.cached),
+            "the pin opens by the path it was made through: {listed:?}"
+        );
+
+        // With the link gone, only a kept copy can answer the read.
+        daemon.client.set_online(false);
+        assert_eq!(std::fs::read(&file).unwrap(), content);
+        daemon.client.set_online(true);
+
+        let unpinned = daemon
+            .request(&Request::Unpin { path: path.clone() })
+            .unwrap();
+        assert!(matches!(unpinned, Response::Ok { .. }), "{unpinned:?}");
+        assert!(pins().is_empty());
+
+        assert!(matches!(daemon.stop(), Ok(MountOutcome::Shutdown)));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    #[ignore = "mounts FUSE: run with `cargo test -p pdfs-fuse sim:: -- --ignored`"]
+    fn a_file_kept_offline_stays_on_disk_through_changes_made_elsewhere() {
+        // A change from another device deleted a pinned file's copy and
+        // nothing downloaded it again, and a file added to a pinned folder
+        // elsewhere was never downloaded: both were listed as kept offline
+        // and read only with a network (B282).
+        let drive = FakeDrive::new();
+        let dir = scratch("pin-keeper");
+        let daemon = Daemon::start(&dir, drive.client(1, Faults::lan())).unwrap();
+        std::fs::create_dir(daemon.mountpoint.join("Docs")).unwrap();
+        std::fs::write(daemon.mountpoint.join("Docs/a.txt"), b"first").unwrap();
+        std::fs::write(daemon.mountpoint.join("solo.txt"), b"alone").unwrap();
+        assert!(wait_until(Duration::from_secs(30), || {
+            daemon.pending().is_ok_and(|items| items.is_empty())
+                && drive.lookup("Docs/a.txt").is_some()
+                && drive.lookup("solo.txt").is_some()
+        }));
+        daemon.request(&Request::PurgeCache).unwrap();
+        let entry = |folder: &str, name: &str| match daemon.request(&Request::ListDir {
+            path: folder.into(),
+        }) {
+            Ok(Response::Entries { entries }) => entries.into_iter().find(|e| e.name == name),
+            _ => None,
+        };
+        for path in ["Docs", "solo.txt"] {
+            let pinned = daemon.request(&Request::Pin { path: path.into() }).unwrap();
+            assert!(matches!(pinned, Response::Ok { .. }), "{pinned:?}");
+        }
+        assert!(wait_until(Duration::from_secs(30), || {
+            entry("Docs", "a.txt").is_some_and(|e| e.cached)
+                && entry("", "solo.txt").is_some_and(|e| e.cached)
+        }));
+
+        // Another device edits both files and adds one to the kept folder.
+        drive.device().write("Docs/a.txt", b"second, and longer");
+        drive.device().write("solo.txt", b"alone, edited");
+        drive.device().write("Docs/new.txt", b"made elsewhere");
+        assert!(
+            wait_until(Duration::from_secs(60), || {
+                entry("Docs", "a.txt").is_some_and(|e| e.cached && e.size == 18)
+                    && entry("", "solo.txt").is_some_and(|e| e.cached && e.size == 13)
+                    && entry("Docs", "new.txt").is_some_and(|e| e.cached)
+            }),
+            "the keeper downloaded the new content: {:?} {:?} {:?}",
+            entry("Docs", "a.txt"),
+            entry("", "solo.txt"),
+            entry("Docs", "new.txt"),
+        );
+
+        // With the link gone, only the kept copies can answer.
+        daemon.client.set_online(false);
+        let read = |rel: &str| std::fs::read(daemon.mountpoint.join(rel)).unwrap();
+        assert_eq!(read("Docs/a.txt"), b"second, and longer");
+        assert_eq!(read("solo.txt"), b"alone, edited");
+        assert_eq!(read("Docs/new.txt"), b"made elsewhere");
+        daemon.client.set_online(true);
+
+        assert!(matches!(daemon.stop(), Ok(MountOutcome::Shutdown)));
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
     /// The synced folder `id` as the daemon lists it.
     fn listed_folder(daemon: &Daemon, id: i64) -> Option<control::SyncFolderInfo> {
         match daemon.request(&Request::ListSyncFolders) {

crates/pdfs-fuse/src/takeout.rs

@@ -344,9 +344,6 @@ impl Core {
                 );
                 let metadata = PhotoUploadMetadata {
                     capture_time: photo.capture_time,
-                    last_modification_time: photo
-                        .capture_time
-                        .and_then(pdfs_core::timestamp::modification_time),
                     ..Default::default()
                 };
                 // A thumbnail is made from a file, so a photo that can have one
@@ -368,13 +365,10 @@ impl Core {
                         let thumbnails = self.upload_thumbnails(path, &photo.name);
                         // No sidecar and no date in the name: the photo's own
                         // EXIF, before Drive files it under today.
-                        let capture_time = metadata
-                            .capture_time
-                            .or_else(|| pdfs_core::exiftime::capture_time_of(path));
                         let metadata = PhotoUploadMetadata {
-                            capture_time,
-                            last_modification_time: capture_time
-                                .and_then(pdfs_core::timestamp::modification_time),
+                            capture_time: metadata
+                                .capture_time
+                                .or_else(|| pdfs_core::exiftime::capture_time_of(path)),
                             ..metadata
                         };
                         std::fs::File::open(path)

docs/ARCHITECTURE.md

@@ -467,6 +467,7 @@ both with `pdfs_core::search::relevance_score`, so the prompt can merge them int
 | `pdfs-sync`, `pdfs-sync-poll` | Mirror passes and the remote poll (§7) |
 | Tokio runtime | Remote calls, and the Drive and photos event streams (§6) |
 | `pdfs-online-probe` | Probes Drive while offline |
+| `pdfs-pin-keeper` | Checks pins once a second for work: every pin at startup, when the link returns and after the event feed loses continuity, and the pins a batch of remote events changed. Downloads files kept offline that are missing or stale; failures retry with a backoff of 30 s to 30 min (`docs/BUGS.md` B282) |
 | `pdfs-supervisor` | Logs workers that hold one job for minutes, a queue that stops draining, and control requests that never return; samples memory; pings the systemd watchdog only after a round trip over the control socket succeeds (`WatchdogSec=120`) |
 | `pdfs-conflict-sweep` | Optional. After 30 s, then every 5 minutes, finds `(sync-conflict …)` copies identical (size and SHA-1) to their original. `conflict_sweep` decides: `off`, `report` (default) or `enforce`, which trashes them after re-checking each one |
 | Smaller helpers | `pdfs-localindex` (home index for search), `pdfs-pause` (ends a timed pause), `pdfs-similar` (similar photos, on request), `pdfs-diagnostics` |

docs/BUGS.md

@@ -109,6 +109,8 @@ a live account since.
 
 | Entry | Title |
 |---|---|
+| [B282](#b282--a-file-kept-offline-is-downloaded-again-after-a-change-made-elsewhere) | A file kept offline is downloaded again after a change made elsewhere |
+| [B281](#b281--a-file-in-a-synced-folder-cannot-be-kept-offline) | A file in a synced folder cannot be kept offline |
 | [B280](#b280--uploading-a-batch-of-large-photos-swaps-the-machine-until-the-daemon-is-killed) | Uploading a batch of large photos swaps the machine until the daemon is killed |
 | [B279](#b279--after-a-watchdog-kill-the-mount-never-comes-back) | After a watchdog kill the mount never comes back |
 | [B278](#b278--sync-list-and-devices-list-show-the-last-sync-as-epoch-seconds) | `sync list` and `devices list` show the last sync as epoch seconds |
@@ -383,6 +385,78 @@ a live account since.
 
 Newest first.
 
+### B282 — A file kept offline is downloaded again after a change made elsewhere
+
+**Status:** Fixed, not verified live
+**Found:** 2026-11-13, while looking into B281. Nothing downloaded a pinned file again after the
+pin had downloaded it once.
+**Where:** `apply_event` in `crates/pdfs-fuse/src/background.rs`; the new pin keeper in
+`crates/pdfs-fuse/src/keeper.rs`
+
+**Repro:** Pin a file, then change it from another device. The event deletes the cached copy.
+The file stays listed as kept offline, `cached` is false, and the next read downloads it, or
+fails without a network. Rename or move it elsewhere and the same happens, though its content
+did not change. Add a file to a pinned folder from another device and it is never downloaded.
+A folder pin whose downloads failed while the link was down never retries them.
+
+**Cause:** A remote change to a known node called `ContentCache::evict`, which does not check
+pins, and only the pin request itself downloaded anything. The copy was also stored under the
+size the listing held at pin time. That is the ciphertext size until the size upgrade lands
+(B12), and a copy stored under it never matches the plaintext it holds.
+
+**Fix:** A remote change no longer evicts a pinned file's copy. The copy is checked against the
+revision's `(mtime, size)`, so a read of a newer revision does not take it. A rename keeps the
+revision's mtime (B123), so the copy stays valid. A pin keeper thread checks pins again and
+downloads files that are missing or stale:
+
+- the pins a batch of remote events changed, after the batch's listings are dropped;
+- a pinned folder that gets a new file;
+- every pin at startup, when the link comes back, and after the event feed loses continuity;
+- a file whose version is restored.
+
+Failed downloads are tried again with a backoff from 30 s to 30 min. Pinning settles a
+provisional size before it stores the copy.
+
+**Test:** `a_file_kept_offline_stays_on_disk_through_changes_made_elsewhere` in
+`crates/pdfs-fuse/src/sim/daemon.rs`. Another device edits a pinned file and a file in a pinned
+folder, and adds a file to that folder. The test waits until all three are cached, then reads
+them with the link down. With the keeper disabled, it fails with all three uncached.
+
+---
+
+### B281 — A file in a synced folder cannot be kept offline
+
+**Status:** Fixed, not verified live
+**Found:** 2026-11-13. An image was made available offline in the app, and it opened from the app
+with no download. `feh` opened it from a terminal and downloaded it each time. The two were not
+the same file. The app had kept `~/ProtonDrive/Pictures/photo.png`, in My files. The
+terminal opened `~/Pictures/photo.png`, in the on-demand synced folder `~/Pictures`. That
+copy is a separate node under Computers, uploaded on its own, with the same name and size but a
+different mtime. The daemon treats every program the same way: it does not look at the process
+that reads.
+**Where:** the `Pin` and `Unpin` handlers in `crates/pdfs-fuse/src/control.rs`
+
+**Repro:** Add a synced folder in on-demand mode and put a file in it. `pdfs pin` on its absolute
+path fails with "is not under the mountpoint". A relative path is resolved against My files, so
+it keeps a file of the same name there, if one exists, or fails. Reading the file in the synced
+folder then downloads it.
+
+**Cause:** Both handlers turned the path into a mount-relative one with `rel_to_mount`, which only
+knows the primary mount. B86 moved `ls`, `refresh`, `rm` and `mv` to `route_to_mount`, which finds
+the mount that serves an absolute path. Pin and unpin were left out.
+
+**Fix:** Pin and unpin route through `route_to_mount` and run on the mount that owns the path. A
+path in a mirror folder gets an error that says its files are already on this computer. The pin
+registry records the absolute local path for a pin made through an on-demand folder, so
+`pdfs pins`, the prompt and the HUD open the file through the folder it was kept from. Pins
+under the primary mount still record the path relative to it.
+
+**Test:** `pinning_a_file_in_an_on_demand_folder_keeps_that_folders_copy` in
+`crates/pdfs-fuse/src/sim/daemon.rs`. It pins a file through an on-demand folder's absolute path,
+takes the link down, and reads the file through that folder.
+
+---
+
 ### B280 — Uploading a batch of large photos swaps the machine until the daemon is killed
 
 **Status:** Fixed, not verified live

docs/CHANGELOG.md

@@ -11,27 +11,60 @@ scratch (user data in `staging/` and `recovery/` is never touched by this).
 
 ## [Unreleased]
 
-### Changed
+## [3.8.0] — 2026-11-12
 
-- Update `proton-sdk` and `proton-drive-rs` to 0.11.0.
-  Convert epoch timestamps at the SDK boundary and explicitly preserve photo modification
-  times now that they are independent of capture times. See [the SDK review](SDK-0.11.0.md)
-  for features and breaking changes.
-Schema: **45**. Synced folders now distinguish device backups from My files attachments.
-Existing folders remain device backups; older builds cannot open the upgraded database.
+Schema: **45**. Synced folders now tell device backups apart from folders attached to My files.
+Existing folders stay device backups. Older builds cannot open the upgraded database.
 
 ### Added
 
-- Shell completion for `pdfs` in bash, zsh and fish, installed by every package, plus elvish
-  and PowerShell through `pdfs completions SHELL`. Besides commands and options it completes
-  paths in My files and the ids and uids the running service knows (synced folders, the queue,
-  computers, trash, albums, shares, invitations, bookmarks, conflicts and versions), each with
-  a description. Share roles are now checked by the CLI (`viewer`, `editor`, `admin`) before
-  the request.
-- `pdfs sync attach PATH --to REMOTE` connects an existing local directory to an existing
-  My files folder. The first sync preserves one-sided files and differing versions (#67).
-  Attachments stay in mirror mode, are excluded from device profiles, and cannot delete
-  the remote root when syncing is stopped.
+- **Sync a local folder with a folder you already have in My files** (#67, #77).
+  `pdfs sync attach ~/Work --to Work` keeps `~/Work` an ordinary local folder and syncs it both
+  ways with My files/Work. The first sync uploads files that are only on this computer, downloads
+  files that are only on Proton Drive, and keeps both versions of a file that differs: the one on
+  Proton Drive keeps its name, and the local one becomes a conflict copy next to it and is
+  uploaded too. Attached folders are always kept on this computer, never online only. They are
+  listed apart from device backups and are not part of the device profile used to restore another
+  computer. Stopping one keeps both copies, and `--delete-remote` is refused for it. If the folder
+  on Proton Drive is trashed or moved out of My files, syncing stops with an error and the local
+  files stay. Attaching a folder is done from a terminal for now.
+
+- **Tab completion for `pdfs`** in bash, zsh and fish, installed by every package. Besides
+  commands and options it completes paths in My files (`pdfs pin Doc<Tab>`) and what the running
+  service knows, each with a description: synced folders, queued changes, computers, trash, albums,
+  items shared with you, invitations, bookmarks and conflict copies, and once a path is typed, the
+  file's versions or the share's members and link. Without the service it still completes commands
+  and options. Elvish and PowerShell load it from `pdfs completions SHELL`, and so does a source
+  build; the [command-line reference](CLI.md#shell-completion) has the line for each shell.
+  `pdfs share` and `pdfs share-role` now check the role (`viewer`, `editor` or `admin`) before
+  sending the request, and `pdfs public-link` does the same for `viewer` and `editor`.
+
+### Fixed
+
+- **My files comes back after the service was killed for hanging** (B279). A killed service left
+  its folders behind as dead mounts, and every restart then failed with `File exists` and retried
+  forever without opening anything, until the mounts were cleared by hand. The service now clears
+  a dead mount before it opens the folder. On a large account a restart that did open My files was
+  killed again, because loading the account took longer than the 2 minutes the service has to
+  report in. Startup now gets 10 minutes, and the 2 minutes apply again once the service answers.
+
+- **Uploading many large photos no longer runs the computer out of memory** (B280). Every image
+  upload decodes the whole picture to make its thumbnail, and up to 16 did so at once. A batch of
+  100-megapixel photos took about 9 GiB, filled the swap, and the service was killed on every
+  restart. Thumbnails now share 512 MiB between them: phone photos are still made side by side,
+  and a very large photo waits and is made on its own.
+
+- **Keep a file offline in an on-demand synced folder** (B281). `pdfs pin` and `pdfs unpin` now
+  accept a path in a synced folder such as `~/Pictures`. Before, they only took paths under the
+  Proton Drive mount, so the copy in the synced folder was downloaded again by every program that
+  read it.
+
+- **Files kept offline stay on this computer when they change elsewhere** (B282). A change from
+  another device, even a rename, deleted the copy of a file kept offline, and nothing downloaded
+  it again, so the next read downloaded it or failed without a network. Files added to a folder
+  kept offline from another device were never downloaded. The copy now stays until the new
+  version is downloaded, which happens on its own. Files kept offline are also checked at
+  startup and when the connection returns, and failed downloads are tried again.
 
 ## [3.7.0] — 2026-11-02
 

docs/CLI.md

@@ -102,7 +102,7 @@ commands are for scripts and for cases where the mount is not available.
 
 | Command | Description |
 |---|---|
-| `pdfs pin PATH` | Download a file completely and keep it on this computer. For a folder, its files download in the background (`pdfs transfers` shows the progress). |
+| `pdfs pin PATH` | Download a file completely and keep it on this computer. For a folder, its files download in the background (`pdfs transfers` shows the progress). PATH can be under the Proton Drive mount or in an on-demand synced folder. A file in a mirror folder is already on this computer. |
 | `pdfs unpin PATH` | Release it back to online only. A file inside a folder kept offline cannot be released on its own. |
 | `pdfs pins` | List files and folders kept available offline. |
 

docs/INSTALL.md

@@ -102,7 +102,7 @@ That URL follows `main`. To stay on releases, pin the input to a release tag ins
 the tag to update:
 
 ```nix
-inputs.proton-drive-linux.url = "github:narrrl/proton-drive-linux/v3.7.0";
+inputs.proton-drive-linux.url = "github:narrrl/proton-drive-linux/v3.8.0";
 ```
 
 Each release tag is built with Nix before the release is published.

docs/SDK-0.11.0.md

@@ -1,60 +0,0 @@
-# SDK 0.11.0 review
-
-Reviewed the sibling `../proton-sdk-rs` checkout at `84039a1` against 0.10.1
-(`48dd410`), including its changelog and source diff.
-
-## Features
-
-- Folder creation, streaming uploads, draft replacement, and revision uploads
-  preserve the supplied timestamp's UTC offset and fractional seconds.
-- `ModificationTime` is exported as an alias for
-  `chrono::DateTime<chrono::FixedOffset>`.
-- Photo modification time can be set independently of capture time. Downloaded
-  claimed modification timestamps remain verbatim strings.
-- Neither SDK crate defines Cargo feature flags. No feature opt-in is needed.
-  The Drive crate now depends directly on `chrono` 0.4; the SDK already used it.
-  The minimum Rust version remains 1.96, matching this workspace.
-
-## Breaking changes and adaptation
-
-The modification-time argument changes from `Option<i64>` to
-`Option<ModificationTime>` on `create_folder`, `upload_file_from`,
-`upload_file_replacing_draft_from`, `upload_new_revision`, and
-`upload_new_revision_from`. `None` remains valid.
-
-The real `DriveApi` adapter converts the client's stored epoch seconds to UTC
-through `pdfs_core::timestamp::modification_time`. Internal storage, the trait,
-and the simulated Drive continue using epoch seconds. Out-of-range timestamps
-are omitted rather than panicking. Existing upload paths still supply whole
-seconds; this bump alone does not add subsecond storage or offset tracking.
-
-`PhotoUploadMetadata` gains `last_modification_time`, and the SDK no longer
-copies `capture_time` into it. Our literals already use `Default`, so this would
-compile while silently changing uploaded metadata. Control uploads, Takeout
-imports (including the EXIF fallback), and redating now set both explicitly to
-preserve the previous behavior when a capture time is known. Without a known
-capture time, modification time stays omitted as before.
-
-No other public API changes were found in the reviewed diff. No database or
-recovery migration is required by this SDK bump.
-
-## Dependencies
-
-The workspace requires the published 0.11.0 versions of both crates from
-crates.io. No local patches or sibling checkout are needed to build it.
-
-## Verification
-
-The published crates' source files match the reviewed sibling checkout at
-`84039a1`. On the final branch based on `main`, these checks passed:
-
-```sh
-cargo test --workspace --locked
-cargo fmt --all -- --check
-cargo clippy --workspace --all-targets --locked -- -D warnings
-```
-
-The test suite reported 1,135 passed and 67 ignored; ignored tests were not run.
-Tests ran outside the sandbox because control-socket tests require socket
-permissions. No live account or mounted-filesystem acceptance testing was
-performed.

packaging/PKGBUILD

@@ -9,7 +9,7 @@
 # Build + install:   cd packaging && makepkg -fi
 
 pkgname=proton-drive-linux
-pkgver=3.7.0
+pkgver=3.8.0
 pkgrel=1
 pkgdesc="Unofficial Proton Drive client for Linux: files-on-demand FUSE mount, CLI, GTK4 app + tray"
 arch=('x86_64')

packaging/proton-drive-linux.spec

@@ -10,7 +10,7 @@
 # Match Arch PKGBUILD `!lto` — LTO has broken some GTK/Rust links in practice.
 %global _lto_cflags %{nil}
 
-%{!?version: %global version 3.7.0}
+%{!?version: %global version 3.8.0}
 %global forge https://github.com/narrrl/proton-drive-linux
 # Files come from the checkout, or from the unpacked tag archive.
 %global src %{?git_dir}%{!?git_dir:.}

po/pdfs.pot

@@ -6,7 +6,7 @@
 #, fuzzy
 msgid ""
 msgstr ""
-"Project-Id-Version: proton-drive-linux 3.7.0\n"
+"Project-Id-Version: proton-drive-linux 3.8.0\n"
 "Report-Msgid-Bugs-To: https://github.com/narrrl/proton-drive-linux/issues\n"
 "POT-Creation-Date: 2026-11-01 17:51+0100\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"

scripts/publish-wiki.sh

@@ -91,7 +91,7 @@ SECTIONS = [
 ]
 
 # Too long or too internal for the wiki; links to them go to GitHub.
-EXCLUDED = {"BUGS.md", "CHANGELOG.md", "SDK-0.11.0.md"}
+EXCLUDED = {"BUGS.md", "CHANGELOG.md"}
 
 # Files outside docs/ whose links are checked but not published.
 CHECKED = ["README.md", "CONTRIBUTING.md", "SECURITY.md"]