fix(ui) improved ux

Cargo.lock

@@ -2200,6 +2200,25 @@ dependencies = [
  "system-deps",
 ]
 
+[[package]]
+name = "h2"
+version = "0.4.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6cb093c84e8bd9b188d4c4a8cb6579fc016968d14c99882163cd3ff402a4f155"
+dependencies = [
+ "atomic-waker",
+ "bytes",
+ "fnv",
+ "futures-core",
+ "futures-sink",
+ "http",
+ "indexmap",
+ "slab",
+ "tokio",
+ "tokio-util",
+ "tracing",
+]
+
 [[package]]
 name = "half"
 version = "2.7.1"
@@ -2367,6 +2386,7 @@ dependencies = [
  "bytes",
  "futures-channel",
  "futures-core",
+ "h2",
  "http",
  "http-body",
  "httparse",
@@ -3518,7 +3538,7 @@ checksum = "35fb2e5f958ec131621fdd531e9fc186ed768cbe395337403ae56c17a74c68ec"
 
 [[package]]
 name = "pdfs-cli"
-version = "1.5.0"
+version = "1.9.0"
 dependencies = [
  "anyhow",
  "clap 4.6.4",
@@ -3533,7 +3553,7 @@ dependencies = [
 
 [[package]]
 name = "pdfs-core"
-version = "1.5.0"
+version = "1.9.0"
 dependencies = [
  "async-trait",
  "directories",
@@ -3546,15 +3566,17 @@ dependencies = [
  "rusqlite",
  "serde",
  "serde_json",
+ "sha1 0.10.7",
  "sha2 0.10.9",
  "thiserror 2.0.19",
  "tokio",
  "tracing",
+ "zip",
 ]
 
 [[package]]
 name = "pdfs-fuse"
-version = "1.5.0"
+version = "1.9.0"
 dependencies = [
  "fuser",
  "futures",
@@ -3565,13 +3587,15 @@ dependencies = [
  "pdfs-core",
  "proton-drive-rs",
  "serde_json",
+ "sha1 0.10.7",
  "tokio",
  "tracing",
+ "zip",
 ]
 
 [[package]]
 name = "pdfs-gui"
-version = "1.5.0"
+version = "1.9.0"
 dependencies = [
  "anyhow",
  "async-channel",
@@ -3832,9 +3856,9 @@ dependencies = [
 
 [[package]]
 name = "proton-drive-rs"
-version = "0.5.1"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3abae5e90e6889b120208159eb2c60b332612e5b708fdf3c14287307ce01715d"
+checksum = "58322795538d66137d2eb071590375c5287e69059c429e2309dc37368ab5b588"
 dependencies = [
  "async-trait",
  "base64",
@@ -3859,9 +3883,9 @@ dependencies = [
 
 [[package]]
 name = "proton-sdk"
-version = "0.5.1"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fa729310c1a66e12bb41b9f5f036c86b9857e76536556052203ffecdb0b44c3"
+checksum = "d77482a3160d14926c65537c64bc95cf27d609597a524c97d97d97d1777e9603"
 dependencies = [
  "aes-gcm 0.11.0",
  "async-trait",
@@ -4252,6 +4276,7 @@ dependencies = [
  "bytes",
  "futures-core",
  "futures-util",
+ "h2",
  "http",
  "http-body",
  "http-body-util",
@@ -5110,6 +5135,7 @@ dependencies = [
  "bytes",
  "futures-core",
  "futures-sink",
+ "libc",
  "pin-project-lite",
  "tokio",
 ]
@@ -5291,6 +5317,12 @@ dependencies = [
  "cipher 0.4.4",
 ]
 
+[[package]]
+name = "typed-path"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e28f89b80c87b8fb0cf04ab448d5dd0dd0ade2f8891bae878de66a75a28600e"
+
 [[package]]
 name = "typenum"
 version = "1.20.1"
@@ -6232,6 +6264,20 @@ dependencies = [
  "syn 2.0.119",
 ]
 
+[[package]]
+name = "zip"
+version = "8.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d04a6b5381502aa6087c94c669499eb1602eb9c5e8198e534de571f7154809b"
+dependencies = [
+ "crc32fast",
+ "flate2",
+ "indexmap",
+ "memchr",
+ "typed-path",
+ "zopfli",
+]
+
 [[package]]
 name = "zlib-rs"
 version = "0.6.6"
@@ -6244,6 +6290,18 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "29666d0abbfad1e3dc4dcf6144730dd3a3ab225bbbdac83319345b1b44ccfc1b"
 
+[[package]]
+name = "zopfli"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f05cd8797d63865425ff89b5c4a48804f35ba0ce8d125800027ad6017d2b5249"
+dependencies = [
+ "bumpalo",
+ "crc32fast",
+ "log",
+ "simd-adler32",
+]
+
 [[package]]
 name = "zune-core"
 version = "0.5.1"

Cargo.toml

@@ -3,15 +3,15 @@ resolver = "2"
 members = ["crates/pdfs-core", "crates/pdfs-fuse", "crates/pdfs-cli", "crates/pdfs-gui"]
 
 [workspace.package]
-version = "1.5.0"
+version = "1.9.0"
 edition = "2024"
 license = "MIT"
 authors = ["Nils Pukropp <contact@narl.io>"]
 rust-version = "1.96"
 
 [workspace.dependencies]
-proton-sdk = { version = "0.5.1" }
-proton-drive-rs = { version = "0.5.1" }
+proton-sdk = { version = "0.6.1" }
+proton-drive-rs = { version = "0.6.1" }
 
 # Internal crates.
 pdfs-core = { path = "crates/pdfs-core" }
@@ -32,6 +32,12 @@ tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 directories = "5"
 ignore = "0.4"
 sha2 = "0.10"
+# Google Takeout exports are zip sets; the importer reads their central
+# directories and streams entries out without extracting to disk first.
+zip = { version = "8", default-features = false, features = ["deflate"] }
+# Proton's photo duplicate detection is keyed on the plaintext SHA-1, so an
+# import has to speak SHA-1 whatever its age.
+sha1 = "0.10"
 # Thumbnail generation for photos the server has none for. Decoders only for the
 # formats a camera or phone actually produces — the rest of the crate's codecs
 # would be dead weight in the daemon.

crates/pdfs-cli/src/main.rs

@@ -158,6 +158,28 @@ enum Command {
     },
     /// List the photo albums (including ones shared with this account).
     Albums,
+    /// Import a Google Photos Takeout export into Proton Photos.
+    ///
+    /// Pass every zip of the export at once — Google splits one export across
+    /// numbered parts, and a photo's metadata often sits in a different part
+    /// than the photo. Albums in the export are recreated as Proton albums, and
+    /// photos already on the account (same name and same content) are skipped,
+    /// so an interrupted import can simply be run again.
+    ImportGooglePhotos {
+        /// The export's `.zip` files (e.g. `takeout-*.zip`).
+        #[arg(required = true)]
+        archives: Vec<PathBuf>,
+        /// Report what would be imported without uploading anything.
+        #[arg(long)]
+        dry_run: bool,
+        /// Stay attached and print progress until the import finishes.
+        #[arg(long)]
+        wait: bool,
+    },
+    /// Show how the running (or last) Google Photos import is doing.
+    ImportStatus,
+    /// Stop the running Google Photos import.
+    CancelImport,
     /// List the photos in one album (newest capture first).
     Album {
         /// Album node uid in `volume~link` form (from `pdfs albums`).
@@ -589,6 +611,13 @@ fn main() -> Result<()> {
         } => cmd_photos(limit, offset, favorites),
         Command::Favorite { uid, remove } => cmd_favorite(uid, remove),
         Command::Albums => cmd_albums(),
+        Command::ImportGooglePhotos {
+            archives,
+            dry_run,
+            wait,
+        } => cmd_import_google_photos(archives, dry_run, wait),
+        Command::ImportStatus => cmd_import_status(),
+        Command::CancelImport => cmd_cancel_import(),
         Command::Album { uid, limit, offset } => cmd_album(uid, limit, offset),
         Command::OpenPhoto { uid } => cmd_open_photo(uid),
         Command::Search { query, limit } => cmd_search(query, limit),
@@ -1336,6 +1365,11 @@ fn cmd_status() -> Result<()> {
             online,
             pending_uploads,
             pending_changes,
+            parked_uploads,
+            failing_ops,
+            failing_error,
+            staged_bytes,
+            staged_oldest_secs,
             ..
         }) => {
             let state = if online { "" } else { ", offline" };
@@ -1344,6 +1378,25 @@ fn cmd_status() -> Result<()> {
                 None => String::new(),
             };
             println!("Mounted at {mountpoint} ({pinned} pinned{state}{queued})");
+            // Everything below is a queue that is not making progress on its
+            // own. Printed only when it exists, because in the ordinary case
+            // there is nothing to say.
+            if staged_bytes > 0 {
+                println!(
+                    "Staged     {} not yet uploaded (oldest {})",
+                    human_bytes(staged_bytes),
+                    human_age(staged_oldest_secs),
+                );
+            }
+            if parked_uploads > 0 {
+                println!("Parked     {parked_uploads} upload(s) waiting for a final filename");
+            }
+            if failing_ops > 0 {
+                println!(
+                    "Stuck      {failing_ops} queued operation(s) keep failing: {}",
+                    failing_error.as_deref().unwrap_or("no error recorded"),
+                );
+            }
         }
         Ok(other) => println!("Mount: unexpected response {other:?}"),
         Err(_) => println!("Mount: not running."),
@@ -1687,6 +1740,104 @@ fn cmd_albums() -> Result<()> {
     Ok(())
 }
 
+fn cmd_import_google_photos(archives: Vec<PathBuf>, dry_run: bool, wait: bool) -> Result<()> {
+    // The daemon opens the archives itself off the shared filesystem, so it gets
+    // absolute paths — the same arrangement `pdfs upload` uses.
+    let mut absolute = Vec::with_capacity(archives.len());
+    for archive in &archives {
+        let path = std::fs::canonicalize(archive)
+            .with_context(|| format!("resolve {}", archive.display()))?;
+        absolute.push(
+            path.to_str()
+                .ok_or_else(|| anyhow!("path is not valid UTF-8: {}", path.display()))?
+                .to_owned(),
+        );
+    }
+
+    match control_request(CtlRequest::ImportTakeout {
+        archives: absolute,
+        dry_run,
+    })? {
+        CtlResponse::Ok { message } => println!("{message}"),
+        CtlResponse::Error { message, kind } => bail!("{}", cli_error(kind, &message)),
+        other => bail!("unexpected response: {other:?}"),
+    }
+    if !wait {
+        println!("Run `pdfs import-status` to follow it.");
+        return Ok(());
+    }
+
+    // Poll rather than stream: the control protocol is request/response, and an
+    // import runs for hours — a held-open socket would be the only long-lived
+    // connection the daemon has.
+    loop {
+        std::thread::sleep(std::time::Duration::from_secs(2));
+        match control_request(CtlRequest::ImportStatus)? {
+            CtlResponse::ImportStatus {
+                running: true,
+                summary: _,
+            } => continue,
+            CtlResponse::ImportStatus { summary, .. } => {
+                print_import_summary(summary.as_ref());
+                return Ok(());
+            }
+            CtlResponse::Error { message, kind } => bail!("{}", cli_error(kind, &message)),
+            other => bail!("unexpected response: {other:?}"),
+        }
+    }
+}
+
+fn cmd_import_status() -> Result<()> {
+    match control_request(CtlRequest::ImportStatus)? {
+        CtlResponse::ImportStatus { running, summary } => {
+            if running {
+                println!("Import running. `pdfs transfers` shows its progress.");
+            }
+            print_import_summary(summary.as_ref());
+        }
+        CtlResponse::Error { message, kind } => bail!("{}", cli_error(kind, &message)),
+        other => bail!("unexpected response: {other:?}"),
+    }
+    Ok(())
+}
+
+fn cmd_cancel_import() -> Result<()> {
+    match control_request(CtlRequest::CancelImport)? {
+        CtlResponse::Ok { message } => println!("{message}"),
+        CtlResponse::Error { message, kind } => bail!("{}", cli_error(kind, &message)),
+        other => bail!("unexpected response: {other:?}"),
+    }
+    Ok(())
+}
+
+fn print_import_summary(summary: Option<&pdfs_core::control::ImportSummary>) {
+    let Some(summary) = summary else {
+        println!("No import has run yet.");
+        return;
+    };
+    println!("Photos in export : {}", summary.found);
+    println!("Uploaded         : {}", summary.uploaded);
+    println!("Already on Proton: {}", summary.duplicates);
+    if summary.skipped_trashed > 0 {
+        println!("Skipped (trash)  : {}", summary.skipped_trashed);
+    }
+    if summary.albums_created > 0 || summary.album_links > 0 {
+        println!(
+            "Albums           : {} created, {} photos filed",
+            summary.albums_created, summary.album_links
+        );
+    }
+    if summary.failed > 0 {
+        println!("Failed           : {}", summary.failed);
+    }
+    if summary.bytes > 0 {
+        println!("Uploaded bytes   : {}", summary.bytes);
+    }
+    if summary.cancelled {
+        println!("Import was cancelled before it finished.");
+    }
+}
+
 fn cmd_album(uid: String, limit: usize, offset: usize) -> Result<()> {
     match control_request(CtlRequest::AlbumPhotos { uid, offset, limit })? {
         CtlResponse::Photos { items, .. } if items.is_empty() => println!("No photos."),
@@ -1886,6 +2037,18 @@ fn path_arg(path: &Path) -> Result<String> {
         .ok_or_else(|| anyhow!("path is not valid UTF-8"))
 }
 
+/// Format an age in seconds for a report line, coarsely — the point of the
+/// number is whether it is minutes or weeks.
+fn human_age(secs: u64) -> String {
+    const UNITS: [(&str, u64); 4] = [("d", 86_400), ("h", 3_600), ("m", 60), ("s", 1)];
+    for (unit, scale) in UNITS {
+        if secs >= scale {
+            return format!("{}{unit}", secs / scale);
+        }
+    }
+    "just now".to_string()
+}
+
 /// Format a byte count for a report line.
 fn human_bytes(bytes: u64) -> String {
     const UNITS: [(&str, f64); 4] = [
@@ -1925,6 +2088,32 @@ fn cmd_cache(action: CacheCmd) -> Result<()> {
     }
 }
 
+/// Ask for a deep integrity check and wait for it to finish.
+///
+/// The daemon answers the request immediately and runs the check on a thread —
+/// it holds the single database connection for as long as it takes, which would
+/// otherwise stall the mount — so a caller that needs the verdict polls for it.
+/// `pdfs doctor` is that caller: it is a diagnostic the user is watching, so
+/// waiting is right, and the bound is generous enough for a large database
+/// without hanging forever if the daemon never finishes.
+fn await_integrity_check() -> Result<CtlResponse> {
+    const POLL: std::time::Duration = std::time::Duration::from_secs(1);
+    const GIVE_UP_AFTER: std::time::Duration = std::time::Duration::from_secs(120);
+
+    let started = std::time::Instant::now();
+    loop {
+        let response = control_request(CtlRequest::CacheInspect { deep: true })?;
+        match &response {
+            CtlResponse::CacheReport {
+                integrity_running: true,
+                integrity_checked: false,
+                ..
+            } if started.elapsed() < GIVE_UP_AFTER => std::thread::sleep(POLL),
+            _ => return Ok(response),
+        }
+    }
+}
+
 fn cmd_cache_inspect(deep: bool) -> Result<()> {
     let response = control_request(CtlRequest::CacheInspect { deep })?;
     if emit_json(&response)? {
@@ -1940,6 +2129,7 @@ fn cmd_cache_inspect(deep: bool) -> Result<()> {
             cache_budget,
             integrity_problems,
             integrity_checked,
+            integrity_running,
         } => {
             println!(
                 "Database   schema v{schema_version}, {}",
@@ -1972,6 +2162,11 @@ fn cmd_cache_inspect(deep: bool) -> Result<()> {
                         println!("  {problem}");
                     }
                 }
+            } else if integrity_running {
+                // The daemon runs the check on a thread rather than holding its
+                // only database connection for the length of it, so the answer
+                // belongs to a later request.
+                println!("\nIntegrity  checking in the background — run this again for the result");
             } else {
                 println!("\nIntegrity  not checked (pass --deep)");
             }
@@ -2209,14 +2404,24 @@ fn cmd_diagnose() -> Result<()> {
                     format!("{pending} waiting to upload")
                 },
             );
-            match control_request(CtlRequest::CacheInspect { deep: true }) {
+            match await_integrity_check() {
                 Ok(CtlResponse::CacheReport {
-                    integrity_problems, ..
+                    integrity_problems,
+                    integrity_checked: true,
+                    ..
                 }) if integrity_problems.is_empty() => report.finding(
                     DiagnoseLevel::Ok,
                     "  database integrity",
                     "SQLite integrity_check passed",
                 ),
+                Ok(CtlResponse::CacheReport {
+                    integrity_checked: false,
+                    ..
+                }) => report.finding(
+                    DiagnoseLevel::Warn,
+                    "  database integrity",
+                    "still checking — run `pdfs cache inspect --deep` for the result",
+                ),
                 Ok(CtlResponse::CacheReport {
                     integrity_problems, ..
                 }) => report.finding(

crates/pdfs-core/Cargo.toml

@@ -18,6 +18,8 @@ tracing.workspace = true
 directories.workspace = true
 ignore.workspace = true
 sha2.workspace = true
+sha1.workspace = true
+zip.workspace = true
 rusqlite.workspace = true
 keyring.workspace = true
 parking_lot.workspace = true

crates/pdfs-core/src/control.rs

@@ -103,6 +103,33 @@ pub enum Request {
     /// re-encrypted for our timeline, which the SDK does not implement yet; the
     /// daemon reports that as an error rather than silently doing nothing.
     SetPhotoFavorite { uid: String, favorite: bool },
+    /// Import Google Photos **Takeout** archives into Proton Photos.
+    ///
+    /// `archives` are absolute paths to the export's `.zip` parts on the
+    /// daemon's own filesystem — the whole set at once, because a photo and its
+    /// metadata sidecar routinely land in different parts. Photos already on the
+    /// account (matched by name *and* content digest) are skipped, so a library
+    /// partly synced by Proton Photos elsewhere does not import twice, and an
+    /// interrupted import resumes by simply being run again.
+    ///
+    /// With `dry_run` the daemon scans and reports what it *would* do without
+    /// uploading anything. Otherwise it acks immediately with
+    /// [`Response::Ok`] and works in the background — an export is hours of
+    /// upload, far past any socket timeout. Progress shows up in
+    /// [`Request::GetQueueStatus`] as a job, and the final counts in
+    /// [`Request::ImportStatus`].
+    ImportTakeout {
+        archives: Vec<String>,
+        #[serde(default)]
+        dry_run: bool,
+    },
+    /// How the running (or last finished) Takeout import is doing. Replies with
+    /// [`Response::ImportStatus`].
+    ImportStatus,
+    /// Ask the running Takeout import to stop. It finishes the photo on the wire
+    /// and files what it has uploaded into its albums, then reports
+    /// `cancelled`. Replies with [`Response::Ok`].
+    CancelImport,
     /// Upload the photo at `source_path` under the given name and media type.
     ///
     /// A path, not the bytes: this protocol is line-delimited JSON, and
@@ -1052,6 +1079,35 @@ pub struct PhotoMonth {
     pub count: usize,
 }
 
+/// How a Google Photos Takeout import is going, or how the last one ended
+/// ([`Response::ImportStatus`]).
+///
+/// The counts are cumulative for the run, so the same shape serves progress and
+/// the final report. `found` counts *distinct* photos: Google stores a separate
+/// copy of a photo in each album folder it appears in, and those fold into one
+/// upload that joins several albums.
+#[derive(Serialize, Deserialize, Debug, Clone, Default, PartialEq, Eq)]
+pub struct ImportSummary {
+    /// Distinct photos the export holds.
+    pub found: usize,
+    /// Photos uploaded by this run.
+    pub uploaded: usize,
+    /// Photos already on the account, matched by name *and* content digest.
+    pub duplicates: usize,
+    /// Photos that could not be read or uploaded.
+    pub failed: usize,
+    /// Photos in the export's trash bucket, which are never imported.
+    pub skipped_trashed: usize,
+    /// Albums created by this run.
+    pub albums_created: usize,
+    /// Album memberships added by this run.
+    pub album_links: usize,
+    /// Bytes uploaded.
+    pub bytes: u64,
+    /// True when the run stopped early because it was cancelled.
+    pub cancelled: bool,
+}
+
 /// One album in a [`Response::Albums`] listing.
 ///
 /// An album is a folder node on the photos volume carrying album properties, so
@@ -1193,6 +1249,28 @@ pub enum Response {
         /// calling a queued `mkdir` an upload is a lie.
         #[serde(default)]
         pending_changes: u64,
+        /// Queued writes held back because the file still wears a transient
+        /// name (a browser's `*.crdownload`, an editor's `*.swp`). They are not
+        /// waiting on the network and will not drain until the finalising
+        /// rename, so they are counted apart from `pending_uploads`.
+        #[serde(default)]
+        parked_uploads: u64,
+        /// Queued ops that have failed enough times to be considered stuck.
+        /// They keep retrying forever — correctly, since their staged bytes are
+        /// the only copy — which is why they have to be visible.
+        #[serde(default)]
+        failing_ops: u64,
+        /// The most recent error from a stuck op, when there is one.
+        #[serde(default)]
+        failing_error: Option<String>,
+        /// Bytes held in `staging/`: writes accepted from the kernel whose only
+        /// copy is on local disk. Never evictable, never counted against the
+        /// cache budget — hence reported separately.
+        #[serde(default)]
+        staged_bytes: u64,
+        /// Age of the oldest staged write, in seconds.
+        #[serde(default)]
+        staged_oldest_secs: u64,
     },
     /// A human-readable success message.
     Ok { message: String },
@@ -1217,6 +1295,12 @@ pub enum Response {
         /// Whether the integrity check actually ran, so an empty problem list
         /// is not mistaken for a clean bill of health it never gave.
         integrity_checked: bool,
+        /// Whether a deep check is running right now. It reads every page of
+        /// the database under the daemon's only connection, so it is answered
+        /// asynchronously: this says "ask again shortly", which is a different
+        /// thing to say than either of the two above.
+        #[serde(default)]
+        integrity_running: bool,
     },
     /// The pin registry.
     Pins { pins: Vec<Pin> },
@@ -1242,6 +1326,14 @@ pub enum Response {
         available: bool,
         items: Vec<AlbumInfo>,
     },
+    /// How the Takeout import is doing (reply to [`Request::ImportStatus`]).
+    /// `running` is false once it has finished, when `summary` is the final
+    /// report; `summary` is `None` when no import has run this session.
+    ImportStatus {
+        running: bool,
+        #[serde(default)]
+        summary: Option<ImportSummary>,
+    },
     /// The months the timeline spans (reply to [`Request::PhotoMonths`]),
     /// newest first.
     PhotoMonths { months: Vec<PhotoMonth> },

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

@@ -33,7 +33,7 @@ impl Db {
     /// whose stored `kind` no longer parses (written by an older build) are
     /// skipped rather than failing the whole read.
     pub fn activity_list(&self, limit: usize) -> Result<Vec<ActivityEntry>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT time, kind, target, detail, ok FROM activity
              ORDER BY id DESC LIMIT ?1",

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

@@ -76,7 +76,7 @@ impl Db {
 
     /// The persisted album listing, in stored order.
     pub fn albums_list(&self) -> Result<Vec<StoredAlbum>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT uid, name, photo_count, cover_uid, last_activity, shared
              FROM albums ORDER BY seq",
@@ -98,7 +98,7 @@ impl Db {
 
     /// Number of albums in the persisted listing.
     pub fn albums_count(&self) -> Result<usize> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let n: i64 = conn.query_row("SELECT COUNT(*) FROM albums", [], |r| r.get(0))?;
         Ok(n.max(0) as usize)
     }
@@ -164,7 +164,7 @@ impl Db {
         offset: usize,
         limit: usize,
     ) -> Result<Vec<StoredPhoto>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT uid, capture_time, name, ratio, thumb_state, kind FROM album_photos
              WHERE album_uid = ?1 ORDER BY seq LIMIT ?2 OFFSET ?3",
@@ -190,7 +190,7 @@ impl Db {
 
     /// How many photos of `album_uid` are persisted.
     pub fn album_photos_count(&self, album_uid: &str) -> Result<usize> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let n: i64 = conn.query_row(
             "SELECT COUNT(*) FROM album_photos WHERE album_uid = ?1",
             [album_uid],
@@ -207,7 +207,7 @@ impl Db {
         if uids.is_empty() {
             return Ok(Vec::new());
         }
-        let conn = self.conn.lock();
+        let conn = self.read();
         let placeholders = vec!["?"; uids.len()].join(",");
         let mut stmt = conn.prepare(&format!(
             "SELECT uid, capture_time, name, ratio, thumb_state, kind FROM album_photos

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

@@ -42,6 +42,30 @@ impl Db {
         Ok(())
     }
 
+    /// Bump `last_accessed` for many keys in one transaction.
+    ///
+    /// The read path touches a key per 128 KiB the kernel asks for — 32 times
+    /// per 4 MiB block — and each of those was its own write transaction under
+    /// the single connection mutex, contending with every `lookup` and
+    /// `readdir`. Callers accumulate touches in memory and flush them here.
+    pub fn cache_accessed_batch(&self, touches: &[(String, i64)]) -> Result<()> {
+        if touches.is_empty() {
+            return Ok(());
+        }
+        let mut conn = self.conn.lock();
+        let tx = conn.transaction()?;
+        {
+            let mut stmt = tx.prepare_cached(
+                "UPDATE cache_entries SET last_accessed = ?2 WHERE cache_key = ?1",
+            )?;
+            for (key, at) in touches {
+                stmt.execute(params![key, at])?;
+            }
+        }
+        tx.commit()?;
+        Ok(())
+    }
+
     /// Drop a single cache-entry row (one evicted blob or block).
     pub fn cache_remove(&self, key: &str) -> Result<()> {
         let conn = self.conn.lock();
@@ -75,7 +99,7 @@ impl Db {
     /// because `enforce_block_budget` runs on every cached block — once per
     /// 4 MiB of every cold read — while holding the shared connection.
     pub fn cache_total_bytes(&self, kind: &str) -> Result<u64> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let total: i64 = conn.query_row(
             "SELECT COALESCE(SUM(size_bytes), 0) FROM cache_entries WHERE kind = ?1",
             params![kind],
@@ -95,7 +119,7 @@ impl Db {
         kind: &str,
         limit: usize,
     ) -> Result<Vec<(String, u64)>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare_cached(
             "SELECT cache_key, size_bytes FROM cache_entries
              WHERE kind = ?1 ORDER BY last_accessed ASC LIMIT ?2",
@@ -115,7 +139,7 @@ impl Db {
     /// (`clear_unpinned`); incremental eviction wants
     /// [`cache_eviction_candidates`](Self::cache_eviction_candidates).
     pub fn cache_entries_by_kind(&self, kind: &str) -> Result<Vec<(String, u64)>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT cache_key, size_bytes FROM cache_entries
              WHERE kind = ?1 ORDER BY last_accessed ASC",

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

@@ -15,7 +15,7 @@ pub struct StoredDevice {
 
 impl Db {
     pub fn device_get(&self) -> Result<Option<StoredDevice>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         conn.query_row(
             "SELECT uid, share_id, root_uid, name, created FROM device LIMIT 1",
             [],

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

@@ -41,32 +41,43 @@ impl Db {
         Ok(next)
     }
 
-    /// Write one batch of walked entries under scan generation `generation`. The
-    /// FTS index is *not* touched here — it is rebuilt once in
-    /// [`local_finish_scan`](Self::local_finish_scan).
+    /// Write one batch of walked entries under scan generation `generation`,
+    /// keeping the FTS index in step with them.
+    ///
+    /// The index is maintained incrementally rather than rebuilt at the end of
+    /// the scan, because a rebuild reads and re-tokenises every row in the table
+    /// — trigrams over a few hundred thousand paths — inside one transaction on
+    /// the single shared connection, which stalls the whole mount for as long as
+    /// it takes. Incremental maintenance is possible here for a reason specific
+    /// to this table: `local_fts` covers `name` and `path`, `path` is the
+    /// table's key, and `name` is derived from it, so an existing row's indexed
+    /// content can never change. Only insertions and deletions touch the index;
+    /// a re-scan that finds the same files does no index work at all.
+    ///
+    /// Hence the update-then-insert shape below rather than an upsert: the
+    /// distinction between "already indexed" and "new row" is exactly what
+    /// decides whether the index needs a write.
     pub fn local_upsert_batch(&self, generation: i64, entries: &[LocalEntry]) -> Result<()> {
         let mut conn = self.conn.lock();
         let tx = conn.transaction()?;
         {
-            let mut stmt = tx.prepare_cached(
-                "INSERT INTO local_files (path, name, is_dir, size, mtime, scan_gen)
-                 VALUES (?1, ?2, ?3, ?4, ?5, ?6)
-                 ON CONFLICT(path) DO UPDATE SET
-                   name     = excluded.name,
-                   is_dir   = excluded.is_dir,
-                   size     = excluded.size,
-                   mtime    = excluded.mtime,
-                   scan_gen = excluded.scan_gen",
+            let mut update = tx.prepare_cached(
+                "UPDATE local_files
+                    SET name = ?2, is_dir = ?3, size = ?4, mtime = ?5, scan_gen = ?6
+                  WHERE path = ?1",
             )?;
+            let mut insert = tx.prepare_cached(
+                "INSERT INTO local_files (path, name, is_dir, size, mtime, scan_gen)
+                 VALUES (?1, ?2, ?3, ?4, ?5, ?6)",
+            )?;
+            let mut index =
+                tx.prepare_cached("INSERT INTO local_fts (rowid, name, path) VALUES (?1, ?2, ?3)")?;
             for e in entries {
-                stmt.execute(params![
-                    e.path,
-                    e.name,
-                    e.is_dir as i64,
-                    e.size,
-                    e.mtime,
-                    generation
-                ])?;
+                let row = params![e.path, e.name, e.is_dir as i64, e.size, e.mtime, generation];
+                if update.execute(row)? == 0 {
+                    insert.execute(row)?;
+                    index.execute(params![tx.last_insert_rowid(), e.name, e.path])?;
+                }
             }
         }
         tx.commit()?;
@@ -74,16 +85,25 @@ impl Db {
     }
 
     /// Close scan generation `generation`: drop every row an older scan wrote
-    /// (those paths are gone from disk), rebuild the FTS index over what remains,
-    /// and stamp the completion time. Returns the number of indexed entries.
+    /// (those paths are gone from disk), drop their FTS entries, and stamp the
+    /// completion time. Returns the number of indexed entries.
+    ///
+    /// The FTS deletes name the old values explicitly, which is how an
+    /// external-content FTS5 table is told to retract a row — see
+    /// [`local_upsert_batch`](Self::local_upsert_batch) for why this is done
+    /// per-row instead of by rebuilding the index.
     pub fn local_finish_scan(&self, generation: i64, finished_at: i64) -> Result<i64> {
         let mut conn = self.conn.lock();
         let tx = conn.transaction()?;
+        tx.execute(
+            "INSERT INTO local_fts (local_fts, rowid, name, path)
+             SELECT 'delete', id, name, path FROM local_files WHERE scan_gen != ?1",
+            params![generation],
+        )?;
         tx.execute(
             "DELETE FROM local_files WHERE scan_gen != ?1",
             params![generation],
         )?;
-        tx.execute_batch("INSERT INTO local_fts(local_fts) VALUES('rebuild');")?;
         tx.execute(
             "INSERT INTO sync_state (key, value) VALUES ('local_indexed_at', ?1)
              ON CONFLICT(key) DO UPDATE SET value = excluded.value",
@@ -98,7 +118,7 @@ impl Db {
     /// has never been built. The daemon uses this to decide whether a fresh mount
     /// needs an immediate rescan or can serve the existing index.
     pub fn local_indexed_at(&self) -> Result<Option<i64>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         Ok(conn
             .query_row(
                 "SELECT value FROM sync_state WHERE key = 'local_indexed_at'",
@@ -118,7 +138,7 @@ impl Db {
         if query.is_empty() {
             return Ok(Vec::new());
         }
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt;
         let rows = if query.chars().count() < TRIGRAM_MIN {
             let pat = format!("%{}%", like_escape(query));
@@ -157,7 +177,7 @@ impl Db {
         if query.is_empty() || limit == 0 {
             return Ok(Vec::new());
         }
-        let conn = self.conn.lock();
+        let conn = self.read();
         let terms = candidate_trigrams(query);
         let lane_limit = limit.div_ceil(2);
         let mut rows: Vec<LocalFileHit> = if terms.is_empty() {
@@ -182,16 +202,36 @@ impl Db {
         if !terms.is_empty()
             && let Some(first) = query.chars().next()
         {
-            let prefix = format!("{}%", like_escape(&first.to_string()));
-            let mut stmt = conn.prepare(
-                "SELECT path, name, is_dir, size, mtime FROM local_files
-                 WHERE name COLLATE NOCASE LIKE ?1 ESCAPE '\\'
-                 ORDER BY name COLLATE NOCASE LIMIT ?2",
-            )?;
-            let fallback = stmt
-                .query_map(params![prefix, lane_limit as i64], local_hit)?
-                .collect::<std::result::Result<Vec<_>, _>>()?;
-            for hit in fallback {
+            // Trigram rank says nothing about how well a name *starts* with the
+            // query, so on a home directory full of dependency trees the pool
+            // fills with vendored files before the obvious answer is reached
+            // (measured: 73% of the 500 best-ranked candidates for "test" came
+            // from one Go module cache). Give whole-query prefix matches their
+            // own lane, newest first, and keep the single-character lane —
+            // which recovers a typo that destroyed every trigram — behind it.
+            let mut lanes = vec![(
+                format!("{}%", like_escape(query)),
+                "ORDER BY mtime DESC LIMIT ?2",
+            )];
+            lanes.push((
+                format!("{}%", like_escape(&first.to_string())),
+                "ORDER BY name COLLATE NOCASE LIMIT ?2",
+            ));
+            let mut extra = Vec::new();
+            for (pattern, order) in lanes {
+                let mut stmt = conn.prepare(&format!(
+                    "SELECT path, name, is_dir, size, mtime FROM local_files
+                     WHERE name COLLATE NOCASE LIKE ?1 ESCAPE '\\' {order}"
+                ))?;
+                extra.extend(
+                    stmt.query_map(params![pattern, lane_limit as i64], local_hit)?
+                        .collect::<std::result::Result<Vec<_>, _>>()?,
+                );
+            }
+            // Prefix hits go in front: `rows` is truncated to `limit` below, and
+            // the lane exists precisely because trigram rank was burying them.
+            let trigram = std::mem::take(&mut rows);
+            for hit in extra.into_iter().chain(trigram) {
                 if !rows.iter().any(|existing| existing.path == hit.path) {
                     rows.push(hit);
                 }

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

@@ -9,7 +9,7 @@ use super::Db;
 use crate::Result;
 
 /// Current schema version. Bump on every forward migration added below.
-pub(super) const SCHEMA_VERSION: i64 = 20;
+pub(super) const SCHEMA_VERSION: i64 = 28;
 
 impl Db {
     pub(super) fn migrate(&self) -> Result<()> {
@@ -101,6 +101,123 @@ impl Db {
         if current < 20 {
             tx.execute_batch(MIGRATION_V20)?;
         }
+        if current < 21 {
+            // A V17-and-older fixture may carry only the tables its own test
+            // cares about; there is nothing to reindex without `nodes`.
+            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 {
+                tx.execute_batch(MIGRATION_V21)?;
+            }
+        }
+        if current < 22 {
+            // Older fixtures (and a database that never grew a table because
+            // its feature was never used) may be missing any of these, and an
+            // index on an absent table is a hard error rather than a no-op.
+            for (table, sql) in MIGRATION_V22 {
+                let present: bool = tx.query_row(
+                    "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = ?1",
+                    [table],
+                    |row| row.get::<_, i64>(0),
+                )? > 0;
+                if present {
+                    tx.execute_batch(sql)?;
+                }
+            }
+            // `activity_time` indexes `time DESC` while both activity queries
+            // order by `id`: it has only ever cost writes.
+            tx.execute_batch("DROP INDEX IF EXISTS activity_time;")?;
+        }
+        if current < 23 {
+            // One last full rebuild of the local index, because from here on the
+            // scan maintains it incrementally (`local_upsert_batch`) and so can
+            // no longer repair a `local_fts` that drifted from `local_files`.
+            // Whatever it costs, it costs once, at startup, before the mount
+            // serves anything.
+            let present: bool = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'local_fts'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            if present {
+                tx.execute_batch("INSERT INTO local_fts(local_fts) VALUES('rebuild');")?;
+            }
+        }
+        if current < 24 {
+            tx.execute_batch(MIGRATION_V24)?;
+        }
+        if current < 25 {
+            // Same guard as V21: an old fixture may not have `nodes` at all,
+            // and there is no path to materialise without it.
+            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 {
+                tx.execute_batch(MIGRATION_V25)?;
+            }
+        }
+        if current < 26 {
+            // Same guard as V22: a fixture that never exercised the queue may
+            // not have `pending_op`, and altering an absent table is an error
+            // rather than a no-op.
+            // A fixture built from the current schema and then rewound to an
+            // older `schema_version` already has the column, and `ADD COLUMN`
+            // has no `IF NOT EXISTS`.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('pending_op') WHERE name = 'claimed_at'",
+                [],
+                |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_V26)?;
+            }
+        }
+        if current < 27 {
+            // Same guards as V26, for the same two reasons: the table may not
+            // exist in an old fixture, and a fixture rewound from the current
+            // schema already has the column.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('pending_op') \
+                 WHERE name = 'access_deferred_since'",
+                [],
+                |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_V27)?;
+            }
+        }
+        if current < 28 {
+            // Same guards as V26/V27, for the same two reasons.
+            let has_column: bool = tx.query_row(
+                "SELECT COUNT(*) FROM pragma_table_info('sync_entry') \
+                 WHERE name = 'local_mtime_ns'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            let has_entries: bool = tx.query_row(
+                "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'sync_entry'",
+                [],
+                |row| row.get::<_, i64>(0),
+            )? > 0;
+            if has_entries && !has_column {
+                tx.execute_batch(MIGRATION_V28)?;
+            }
+        }
         tx.execute(
             "INSERT INTO sync_state (key, value) VALUES ('schema_version', ?1)
              ON CONFLICT(key) DO UPDATE SET value = excluded.value",
@@ -527,3 +644,205 @@ const MIGRATION_V20: &str = "
 ALTER TABLE photos ADD COLUMN favorite INTEGER NOT NULL DEFAULT 0;
 CREATE INDEX IF NOT EXISTS idx_photos_favorite ON photos(favorite, seq);
 ";
+
+/// V21: rebuild the node search index after fixing what counts as indexable.
+///
+/// The v16 backfill rooted its path walk at any node whose parent is null *or*
+/// not cached, but the write path's `node_is_indexable_tx` demanded a
+/// null-parent ancestor. Only the My Files root has one — a device folder's
+/// root is stored in `device`/`sync_folder`, never in `nodes` — so every node
+/// under a device folder was dropped from `nodes_fts` the first time it was
+/// upserted after the backfill, and was unfindable from the prompt (2,705 of
+/// 9,252 nodes on the account this was diagnosed against).
+///
+/// The rule now matches the backfill, so this replays it: same recursive walk
+/// as v16, over the current `nodes`.
+/// Two details the v16 backfill did not carry, both cheap here: a node under a
+/// trashed folder stays out (the write path has always excluded it, and
+/// `tombstone_subtree_tx` only marks a subtree it was told about), and the walk
+/// is depth-capped so a parent cycle in a corrupted database cannot spin the
+/// migration forever.
+const MIGRATION_V21: &str = "
+DROP TABLE IF EXISTS nodes_fts;
+CREATE VIRTUAL TABLE nodes_fts USING fts5(
+  name, path, tokenize='trigram'
+);
+INSERT INTO nodes_fts (rowid, name, path)
+WITH RECURSIVE paths(rowid, uid, path, trashed, depth) AS (
+  -- Only a true root (no parent at all) contributes nothing to the path: its
+  -- name is the mount. A row whose parent is merely uncached is an ordinary
+  -- folder and keeps its name, which is what `path_of` does at runtime.
+  SELECT n.rowid, n.uid,
+         CASE WHEN n.parent_uid IS NULL THEN '' ELSE n.name END, n.trashed, 0
+    FROM nodes n
+   WHERE n.parent_uid IS NULL
+      OR NOT EXISTS (SELECT 1 FROM nodes p WHERE p.uid = n.parent_uid)
+  UNION ALL
+  SELECT n.rowid, n.uid,
+         CASE WHEN paths.path = '' THEN n.name ELSE paths.path || '/' || n.name END,
+         MAX(paths.trashed, n.trashed), paths.depth + 1
+    FROM nodes n JOIN paths ON n.parent_uid = paths.uid
+   WHERE paths.depth < 256
+)
+SELECT n.rowid, n.name, paths.path
+  FROM nodes n JOIN paths ON paths.rowid = n.rowid
+ WHERE paths.trashed = 0;
+";
+
+/// V22: indexes for the lookups that were scanning, each paired with the table
+/// it needs to exist for.
+///
+/// Each backs a query on a hot path that had no index to use:
+///
+/// - `sync_entry(remote_uid)` — the reconcile resolves a remote uid to its
+///   local entry once per node, per pass.
+/// - `local_files(scan_gen)` — the sweep that retires the previous generation
+///   after a local index scan.
+/// - `nodes(parent_uid) WHERE trashed = 0` — every listing, with the partial
+///   index keeping it to the live rows a listing actually wants.
+///
+/// Deliberately *not* here: an index on `pending_op(next_attempt_at, id)`.
+/// `next_due_op` orders by `id`, which is the rowid, so it already stops at the
+/// first due row; offering the planner a `next_attempt_at` index makes it scan
+/// that index and then sort the matches by `id` instead —
+/// `next_due_op_does_not_scale_with_queue_length` measures the regression.
+const MIGRATION_V22: [(&str, &str); 3] = [
+    (
+        "sync_entry",
+        "CREATE INDEX IF NOT EXISTS idx_sync_entry_remote_uid ON sync_entry(remote_uid);",
+    ),
+    (
+        "local_files",
+        "CREATE INDEX IF NOT EXISTS idx_local_files_scan_gen ON local_files(scan_gen);",
+    ),
+    (
+        "nodes",
+        "CREATE INDEX IF NOT EXISTS idx_nodes_parent_live ON nodes(parent_uid) WHERE trashed = 0;",
+    ),
+];
+
+/// V24: the revisions this daemon sealed itself, so restarting does not reopen
+/// the conflict hole B70 layer B closed.
+///
+/// `Core::own_sealed_revs` held these in memory: a queued write whose baseline
+/// names an earlier revision is a conflict *unless* the remote sits at a
+/// revision we sealed, in which case it is one writer stalling and resuming and
+/// must supersede rather than fork a `(sync-conflict)` copy. Losing the map at
+/// shutdown meant the first drain after a restart could not tell the two apart.
+///
+/// `sealed_at` is what bounds the table: entries older than the window in which
+/// a stall→resume is plausible are pruned on write.
+const MIGRATION_V24: &str = "
+CREATE TABLE IF NOT EXISTS own_sealed_rev (
+  uid         TEXT PRIMARY KEY,
+  revision_id TEXT NOT NULL,
+  sealed_at   INTEGER NOT NULL
+);
+";
+
+/// V25: `nodes.path` — a node's mountpoint-relative path, stored rather than
+/// walked.
+///
+/// `path_of` was a recursive CTE per node, and search ran it once per candidate
+/// (up to a thousand per keystroke) on top of the one the write path already ran
+/// per descendant of every folder upsert. The value only changes when a node's
+/// name or parent changes, which is exactly when the write path is already
+/// walking the subtree — so it belongs in a column.
+///
+/// The backfill is the same walk V21 used for `nodes_fts`, minus the trashed
+/// filter: a trashed node stays out of the index but still has a path. Roots get
+/// `''` (their name is the mount), and a node whose parent is merely uncached
+/// keeps its own name — both matching what `path_of` returned at runtime.
+///
+/// Materialised into a temp table rather than written by a correlated subquery,
+/// so the recursive walk runs once instead of once per row.
+const MIGRATION_V25: &str = "
+ALTER TABLE nodes ADD COLUMN path TEXT;
+
+CREATE TEMP TABLE node_paths (uid TEXT PRIMARY KEY, path TEXT NOT NULL);
+
+INSERT INTO node_paths (uid, path)
+WITH RECURSIVE paths(uid, path, depth) AS (
+  SELECT n.uid, CASE WHEN n.parent_uid IS NULL THEN '' ELSE n.name END, 0
+    FROM nodes n
+   WHERE n.parent_uid IS NULL
+      OR NOT EXISTS (SELECT 1 FROM nodes p WHERE p.uid = n.parent_uid)
+  UNION ALL
+  SELECT n.uid,
+         CASE WHEN paths.path = '' THEN n.name ELSE paths.path || '/' || n.name END,
+         paths.depth + 1
+    FROM nodes n JOIN paths ON n.parent_uid = paths.uid
+   WHERE paths.depth < 256
+)
+SELECT uid, path FROM paths;
+
+UPDATE nodes
+   SET path = (SELECT p.path FROM node_paths p WHERE p.uid = nodes.uid)
+ WHERE EXISTS (SELECT 1 FROM node_paths p WHERE p.uid = nodes.uid);
+
+DROP TABLE node_paths;
+";
+
+/// V26: `pending_op.claimed_at` — the drain's claim column.
+///
+/// The drain was one thread taking one op at a time, so a 10 GiB upload held
+/// every queued rename and small write behind it for as long as it ran. Several
+/// workers can share the queue only if a claim is visible to the others: this
+/// column is what makes "already being drained by someone" a fact about the row
+/// rather than about one thread's local variable.
+///
+/// `0` is unclaimed; anything else is the ms at which a worker took it. A
+/// claim is process-local state that outlives nothing — the single-writer lock
+/// means a non-zero value found at open belongs to a crashed run, and
+/// [`Db::clear_op_claims`](super::Db::clear_op_claims) drops the lot.
+///
+/// The index is partial so it costs nothing on the ordinary row: only the
+/// handful of claimed rows are in it, which is exactly the set the claim query
+/// has to subtract to keep two workers off one node.
+const MIGRATION_V26: &str = "
+ALTER TABLE pending_op ADD COLUMN claimed_at INTEGER NOT NULL DEFAULT 0;
+
+CREATE INDEX IF NOT EXISTS idx_pending_op_claimed
+    ON pending_op(uid) WHERE claimed_at <> 0;
+";
+
+/// Schema v27: when an op was first deferred by the local access check.
+///
+/// An access deferral consumes no attempt and records no error — the op has not
+/// failed remotely, it has not been sent at all. That is right for a permission
+/// change the user is about to undo, and wrong for a condition that never
+/// clears: the row is re-deferred every
+/// [`DRAIN_ACCESS_RECHECK`](../../../pdfs_fuse/drain/constant.DRAIN_ACCESS_RECHECK.html)
+/// forever while `attempts`, `last_error`, `failing` and the logs all stay
+/// empty, so a queue that can never drain is indistinguishable from a busy one.
+/// Found in the field as 28 revision ops holding 18 GiB of accepted writes for
+/// 30 days, none of them visible anywhere.
+///
+/// `0` means "not currently access-deferred"; anything else is the ms at which
+/// the first consecutive deferral happened, which is what
+/// [`Db::defer_op_for_access`](super::Db::defer_op_for_access) measures the
+/// deferral against.
+const MIGRATION_V27: &str = "
+ALTER TABLE pending_op ADD COLUMN access_deferred_since INTEGER NOT NULL DEFAULT 0;
+";
+
+/// Schema v28: sub-second precision for a mirror folder's local baseline.
+///
+/// A reconcile pass decides whether the local side of a path changed by
+/// comparing `(local_mtime, local_size)` against the baseline. Both sides of
+/// that comparison were whole seconds, so an edit that landed in the same second
+/// 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).
+///
+/// Nullable rather than a converted `local_mtime * 1_000_000_000`: the
+/// nanosecond part of an existing baseline is genuinely unknown, and inventing
+/// zero for it would make every already-synced file compare as changed and
+/// re-upload an entire mirror on first start. `NULL` means "this row predates
+/// the column", which the comparison reads as "fall back to whole seconds" —
+/// exactly the behaviour that row was written under. Each row gains a real value
+/// the next time its path is synced.
+const MIGRATION_V28: &str = "
+ALTER TABLE sync_entry ADD COLUMN local_mtime_ns INTEGER;
+";

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

@@ -2,9 +2,17 @@
 //! inode bookkeeping, full-text search, content-cache LRU tracking, and pins.
 //!
 //! Only the daemon (`pdfs-fuse`) opens this for writes; the GUI and CLI reach
-//! the same data through the control socket. The connection is wrapped in a
-//! `Mutex` because the FUSE callbacks are synchronous and already serialize
-//! behind the `State` lock, so a connection pool would be overkill.
+//! the same data through the control socket. There is one write connection
+//! behind a `Mutex` — SQLite allows exactly one writer, and the single-instance
+//! `flock` makes sure it is ours — and a small pool of read-only connections
+//! behind [`Db::read`], which every `SELECT`-only method uses.
+//!
+//! The pool is what makes WAL worth having. The original justification for a
+//! single connection was that "FUSE callbacks already serialize behind the
+//! `State` lock"; that stopped being true when reads moved onto an 11-thread
+//! worker pool, and a lookup then queued behind whatever listing happened to be
+//! committing. Under WAL a reader never blocks the writer and vice versa, so the
+//! only thing left serialising them was this process's own mutex.
 //!
 //! This module is the P0 foundation: it opens the database, enables WAL, and
 //! applies the forward-only schema migrations. Write-through of nodes, the
@@ -18,8 +26,10 @@
 use parking_lot::Mutex;
 use rusqlite::Connection;
 
-use crate::Result;
-use std::path::Path;
+use crate::{Error, Result};
+use std::fs::File;
+use std::os::fd::AsRawFd;
+use std::path::{Path, PathBuf};
 
 mod activity;
 mod albums;
@@ -50,6 +60,7 @@ pub use ops::{
     PendingCounts, PendingOp, RenameMeta, op_supersedes,
 };
 pub use photos::{StoredPhoto, THUMB_HAVE, THUMB_NONE, THUMB_UNKNOWN, TimelineRow};
+pub use pins::PinRow;
 pub use sync::{StoredSyncEntry, StoredSyncFolder};
 pub use trash::StoredTrash;
 
@@ -65,18 +76,208 @@ const WAL_SIZE_LIMIT: i64 = 64 * 1024 * 1024;
 /// genuinely stuck holder surfaces as an error rather than an apparent hang.
 const BUSY_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(5);
 
+/// Page cache, in KiB (applied negated, which is how SQLite reads a size in KiB
+/// rather than in pages). 32 MiB against a database that is typically tens of
+/// MiB: large enough to hold the working set of a listing-heavy session, small
+/// enough to be unremarkable in a desktop daemon's RSS.
+const CACHE_SIZE_KIB: i64 = 32 * 1024;
+
+/// Ceiling on the memory-mapped window over the database file. 256 MiB covers
+/// any realistic index while keeping the mapping bounded.
+const MMAP_SIZE: i64 = 256 * 1024 * 1024;
+
+/// WAL pages between automatic checkpoints (default 1000, i.e. ~4 MiB). Halved
+/// so the synchronous checkpoint a committing thread inherits stays short.
+const WAL_AUTOCHECKPOINT_PAGES: i64 = 500;
+
 /// Handle to the unified metadata database.
 ///
 /// Cheap to wrap in an `Arc`; clone the `Arc`, not this. All access goes through
 /// the inner `Mutex<Connection>`.
 pub struct Db {
     conn: Mutex<Connection>,
+    /// Read-only connections for `SELECT`-only methods. `None` for an in-memory
+    /// database, where a second connection would open a different, empty one —
+    /// those fall back to the write connection.
+    readers: Option<ReadPool>,
+    /// The single-writer lock, held open for as long as this handle lives.
+    ///
+    /// Never read; dropping the `File` is what releases the `flock`, so it has
+    /// to be owned here rather than by `open`'s stack frame. `None` for
+    /// in-memory databases, which nothing else can reach.
+    _single_writer: Option<File>,
+}
+
+/// Idle read-only connections, opened on demand and kept for reuse.
+///
+/// Not a bounded pool: the number in flight is bounded by the number of threads
+/// that can be inside a read at once (the FUSE worker lanes plus the control
+/// handlers), and blocking one of those on a permit would reintroduce exactly
+/// the queueing this exists to remove. Only the *idle* set is capped, so a burst
+/// does not leave a connection per thread parked forever.
+struct ReadPool {
+    path: PathBuf,
+    idle: Mutex<Vec<Connection>>,
+}
+
+/// How many idle read connections to keep. Enough that the steady state never
+/// reopens, small enough to be unremarkable.
+const MAX_IDLE_READERS: usize = 4;
+
+impl ReadPool {
+    fn take(&self) -> Option<Connection> {
+        if let Some(conn) = self.idle.lock().pop() {
+            return Some(conn);
+        }
+        match open_read_only(&self.path) {
+            Ok(conn) => Some(conn),
+            Err(error) => {
+                // Falling back to the write connection is correct, just slower,
+                // so this is a warning and not a failed read.
+                tracing::warn!(%error, "could not open a read-only connection");
+                None
+            }
+        }
+    }
+
+    fn put(&self, conn: Connection) {
+        let mut idle = self.idle.lock();
+        if idle.len() < MAX_IDLE_READERS {
+            idle.push(conn);
+        }
+    }
+}
+
+/// A connection to read through: one borrowed from [`ReadPool`], or the write
+/// connection when there is no pool (in-memory) or opening one failed.
+///
+/// Derefs to `Connection`, so a method converts by swapping `self.conn.lock()`
+/// for `self.read()` and nothing else.
+pub(super) struct Reader<'a> {
+    pooled: Option<Connection>,
+    writer: Option<parking_lot::MutexGuard<'a, Connection>>,
+    pool: Option<&'a ReadPool>,
+}
+
+impl std::ops::Deref for Reader<'_> {
+    type Target = Connection;
+
+    fn deref(&self) -> &Connection {
+        self.pooled
+            .as_ref()
+            .or(self.writer.as_deref())
+            .expect("a Reader always holds one of the two")
+    }
+}
+
+impl Drop for Reader<'_> {
+    fn drop(&mut self) {
+        if let (Some(conn), Some(pool)) = (self.pooled.take(), self.pool) {
+            pool.put(conn);
+        }
+    }
+}
+
+/// Open a second connection to the same file for reads only.
+///
+/// `SQLITE_OPEN_READ_ONLY` plus `query_only` is belt and braces: the flag stops
+/// a routing mistake at the file, the pragma stops it at the statement. The rest
+/// mirror [`Db::open_configured`] — a read connection has its own page cache,
+/// its own temp store and its own busy timeout, and gets nothing from the
+/// writer's.
+///
+/// `journal_mode` is deliberately absent: it is a property of the database file,
+/// which the writer already set to WAL, and a read-only connection cannot change
+/// it anyway.
+fn open_read_only(path: &Path) -> Result<Connection> {
+    use rusqlite::OpenFlags;
+    let conn = Connection::open_with_flags(
+        path,
+        OpenFlags::SQLITE_OPEN_READ_ONLY | OpenFlags::SQLITE_OPEN_NO_MUTEX,
+    )?;
+    conn.busy_timeout(BUSY_TIMEOUT)?;
+    conn.pragma_update(None, "cache_size", -CACHE_SIZE_KIB)?;
+    conn.pragma_update(None, "temp_store", "MEMORY")?;
+    conn.pragma_update(None, "mmap_size", MMAP_SIZE)?;
+    conn.pragma_update(None, "query_only", true)?;
+    Ok(conn)
 }
 
 impl Db {
     /// Open (creating if absent) the database at `path`, enable WAL, and bring
     /// the schema up to [`SCHEMA_VERSION`].
+    ///
+    /// Takes the single-instance lock first (see
+    /// [`acquire_single_writer_lock`]), and rebuilds from empty if what is on
+    /// disk turns out not to be a readable database (see [`is_corrupt`]).
     pub fn open(path: &Path) -> Result<Self> {
+        let single_writer = acquire_single_writer_lock(path)?;
+        let conn = match Self::open_configured(path) {
+            Ok(conn) => conn,
+            Err(e) if is_corrupt(&e) => {
+                // Every byte in here is derived from the account or from the
+                // content cache directory, so the recovery is to start over —
+                // loudly, and keeping the damaged file for a post-mortem rather
+                // than deleting evidence.
+                tracing::error!(
+                    db = %path.display(),
+                    error = %e,
+                    "cache database is corrupt — moving it aside and rebuilding \
+                     (metadata will be re-fetched; no user data is stored here)"
+                );
+                quarantine_corrupt_db(path)?;
+                Self::open_configured(path)?
+            }
+            Err(e) => return Err(e),
+        };
+        let db = Self {
+            conn: Mutex::new(conn),
+            // No pool for `:memory:`. A second connection to that name is a
+            // second, empty database rather than another view of this one, so
+            // every routed read would find a schema that does not exist.
+            readers: (!is_in_memory(path)).then(|| ReadPool {
+                path: path.to_path_buf(),
+                idle: Mutex::new(Vec::new()),
+            }),
+            _single_writer: single_writer,
+        };
+        // A drain claim names a worker thread in the process that took it, and
+        // the single-writer lock above says that process is not running. Any
+        // claim still on disk is therefore a crashed run's, and leaving it would
+        // hide those ops from every worker for good.
+        match db.clear_op_claims() {
+            Ok(0) => {}
+            Ok(n) => tracing::info!(ops = n, "released drain claims left by a previous run"),
+            Err(e) => tracing::warn!(error = %e, "clearing stale drain claims failed"),
+        }
+        Ok(db)
+    }
+
+    /// A connection for a `SELECT`-only method.
+    ///
+    /// Reads see the last committed state, which is the same thing they saw
+    /// through the write connection: every method here commits before it
+    /// returns, and nothing holds a transaction open across calls.
+    pub(super) fn read(&self) -> Reader<'_> {
+        if let Some(pool) = &self.readers
+            && let Some(conn) = pool.take()
+        {
+            return Reader {
+                pooled: Some(conn),
+                writer: None,
+                pool: Some(pool),
+            };
+        }
+        Reader {
+            pooled: None,
+            writer: Some(self.conn.lock()),
+            pool: None,
+        }
+    }
+
+    /// Open the file, apply every PRAGMA, and migrate. Split out of
+    /// [`open`](Self::open) so the corruption path can retry it verbatim.
+    fn open_configured(path: &Path) -> Result<Connection> {
         let conn = Connection::open(path)?;
         // WAL: readers never block the single writer. NORMAL sync is the
         // standard durability/throughput tradeoff for WAL.
@@ -101,12 +302,39 @@ impl Db {
         // (Bare SQLite does default to 0, which is where the belief that this
         // was unset came from. That default is not what we get.)
         conn.busy_timeout(BUSY_TIMEOUT)?;
+        // Page cache. The default is 2 MiB, against a schema whose hot table
+        // stores a JSON blob per node — a listing of a few thousand files
+        // evicts itself while it is being read.
+        conn.pragma_update(None, "cache_size", -CACHE_SIZE_KIB)?;
+        // Sorts and recursive CTEs materialise their intermediate results.
+        // Every `ORDER BY … COLLATE NOCASE` listing and every ancestor walk
+        // spills those to a file in `/tmp` by default; they are small and
+        // short-lived, so memory is both faster and less surprising.
+        conn.pragma_update(None, "temp_store", "MEMORY")?;
+        // Read the database through the page cache of the OS rather than
+        // `pread` per page. Bounded rather than unlimited so the daemon's RSS
+        // does not track the database size.
+        conn.pragma_update(None, "mmap_size", MMAP_SIZE)?;
+        // Checkpointing is synchronous in whichever thread happens to commit
+        // the transaction that crosses the threshold — often a FUSE callback.
+        // A smaller autocheckpoint makes that debt smaller and more frequent
+        // rather than rare and multi-second.
+        conn.pragma_update(None, "wal_autocheckpoint", WAL_AUTOCHECKPOINT_PAGES)?;
 
         let db = Self {
             conn: Mutex::new(conn),
+            readers: None,
+            _single_writer: None,
         };
         db.migrate()?;
-        Ok(db)
+        Ok(db.into_conn())
+    }
+
+    /// Unwrap the connection back out of a temporary handle. Only
+    /// [`open_configured`](Self::open_configured) uses it, to run `migrate`
+    /// (which is written against `&self`) before the real handle exists.
+    fn into_conn(self) -> Connection {
+        self.conn.into_inner()
     }
 
     /// Open an in-memory database. For tests.
@@ -119,6 +347,8 @@ impl Db {
         conn.pragma_update(None, "foreign_keys", "ON")?;
         let db = Self {
             conn: Mutex::new(conn),
+            readers: None,
+            _single_writer: None,
         };
         db.migrate()?;
         Ok(db)
@@ -132,5 +362,102 @@ impl Db {
     }
 }
 
+/// Whether `path` names the in-memory database rather than a file. Both
+/// spellings SQLite accepts are checked, because neither has a lock file or a
+/// corruption story.
+fn is_in_memory(path: &Path) -> bool {
+    let p = path.as_os_str();
+    p == ":memory:" || p.is_empty()
+}
+
+/// Take the single-instance write lock for the database at `path`.
+///
+/// The daemon is the only writer by design — the front-ends go through the
+/// control socket — but nothing stopped a hand-run `pdfs mount` from starting
+/// alongside the systemd unit, at which point two processes own the same inode
+/// space, the same content cache, and the same drain queue. SQLite's own
+/// locking makes each *statement* safe and does nothing about that.
+///
+/// `flock` on a sibling `.lock` file rather than on the database itself:
+/// SQLite uses POSIX record locks, so the two never interact, and a lock file
+/// left behind carries no state — the lock lives in the kernel and dies with
+/// the process, however it exits.
+fn acquire_single_writer_lock(path: &Path) -> Result<Option<File>> {
+    if is_in_memory(path) {
+        return Ok(None);
+    }
+    let lock_path = lock_path_for(path);
+    let file = std::fs::OpenOptions::new()
+        .create(true)
+        .read(true)
+        .truncate(false)
+        .write(true)
+        .open(&lock_path)?;
+    // SAFETY: `file` owns the descriptor and outlives the call.
+    let rc = unsafe { libc::flock(file.as_raw_fd(), libc::LOCK_EX | libc::LOCK_NB) };
+    if rc != 0 {
+        let e = std::io::Error::last_os_error();
+        if e.raw_os_error() == Some(libc::EWOULDBLOCK) {
+            return Err(Error::Other(format!(
+                "another Proton Drive daemon is already using {} — \
+                 stop it first (`systemctl --user stop proton-drive.service`)",
+                path.display()
+            )));
+        }
+        return Err(Error::Io(e));
+    }
+    Ok(Some(file))
+}
+
+fn lock_path_for(path: &Path) -> PathBuf {
+    let mut name = path.as_os_str().to_owned();
+    name.push(".lock");
+    PathBuf::from(name)
+}
+
+/// Whether `e` says the file is not a usable database, as opposed to any other
+/// failure. These are the only two conditions rebuilding fixes; a disk error, a
+/// permission problem or a newer-than-supported schema must all still fail.
+fn is_corrupt(e: &Error) -> bool {
+    matches!(
+        e,
+        Error::Db(rusqlite::Error::SqliteFailure(inner, _))
+            if inner.code == rusqlite::ErrorCode::DatabaseCorrupt
+                || inner.code == rusqlite::ErrorCode::NotADatabase
+    )
+}
+
+/// Move a damaged database (and its WAL sidecars) out of the way so the next
+/// open starts from empty.
+///
+/// Renamed rather than deleted: this is a cache, but it is also the only
+/// evidence of what went wrong, and it costs one file the user can remove.
+fn quarantine_corrupt_db(path: &Path) -> Result<()> {
+    let stamp = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0);
+    for suffix in ["", "-wal", "-shm"] {
+        let mut from = path.as_os_str().to_owned();
+        from.push(suffix);
+        let from = PathBuf::from(from);
+        if !from.exists() {
+            continue;
+        }
+        let mut to = path.as_os_str().to_owned();
+        to.push(format!(".corrupt-{stamp}{suffix}"));
+        let to = PathBuf::from(to);
+        // A failure to rename the sidecars is survivable — SQLite discards a
+        // WAL whose database header no longer matches — but failing to move the
+        // database itself is not, because the retry would hit the same file.
+        match std::fs::rename(&from, &to) {
+            Ok(()) => tracing::warn!(from = %from.display(), to = %to.display(), "quarantined"),
+            Err(e) if suffix.is_empty() => return Err(Error::Io(e)),
+            Err(e) => tracing::warn!(file = %from.display(), error = %e, "could not quarantine"),
+        }
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests;

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

@@ -74,7 +74,7 @@ impl Db {
 
     /// Every local location, with device fields joined from `sync_folder`.
     pub fn mount_list(&self) -> Result<Vec<MountSpec>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT
                  m.id,

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

@@ -10,7 +10,9 @@ use crate::{Access, Result};
 use proton_drive_rs::proton_sdk::ids::{LinkId, NodeUid, VolumeId};
 use proton_drive_rs::{Node, NodeKind};
 
-use super::utils::{TRIGRAM_MIN, collect_pairs, like_escape, pair, path_of};
+use super::utils::{
+    HitRow, TRIGRAM_MIN, collect_hits, hit_row, join_path, like_escape, path_of, walk_path_of,
+};
 
 pub struct StoredNode {
     pub node: Node,
@@ -59,7 +61,7 @@ impl Db {
     /// flag. Synthetic shared listings use this to serve the last completed
     /// snapshot while offline, including after a live event expired its TTL.
     pub fn visible_children(&self, parent: &NodeUid) -> Result<Vec<Node>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT node_json FROM nodes
               WHERE parent_uid = ?1 AND trashed = 0 AND node_json IS NOT NULL
@@ -285,7 +287,7 @@ impl Db {
     /// 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.conn.lock();
+        let conn = self.read();
         let count: i64 = conn.query_row(
             "SELECT COUNT(*) FROM nodes WHERE parent_uid = ?1 AND trashed = 0",
             params![uid_str],
@@ -294,6 +296,25 @@ impl Db {
         Ok(count > 0)
     }
 
+    /// A node's mountpoint-relative path, or `None` when it is not cached.
+    ///
+    /// One indexed read of the stored `path`. Callers that need to relate many
+    /// nodes to a handful of roots — search decorating each hit with its
+    /// mountpoint — resolve the roots once through this and do the rest as
+    /// string arithmetic, instead of a `path_relative_to` walk per pair.
+    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| {
+                r.get(0)
+            })
+            .optional()?;
+        if exists.is_none() {
+            return Ok(None);
+        }
+        Ok(Some(path_of(&conn, uid)?))
+    }
+
     /// Resolve `uid` relative to an ancestor node.
     ///
     /// This is used when a remote subtree has its own local sync mount: the
@@ -302,7 +323,7 @@ impl Db {
     /// chain keeps callers from accidentally joining a Drive-wide path onto the
     /// wrong mountpoint. The ancestor itself resolves to the empty path.
     pub fn path_relative_to(&self, ancestor_uid: &str, uid: &str) -> Result<Option<String>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "WITH RECURSIVE anc(uid, parent_uid, name, depth) AS (
                SELECT uid, parent_uid, name, 0 FROM nodes WHERE uid = ?1
@@ -338,15 +359,15 @@ impl Db {
         if query.is_empty() {
             return Ok(Vec::new());
         }
-        let conn = self.conn.lock();
-        let rows: Vec<(String, String)> = if query.chars().count() < TRIGRAM_MIN {
+        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(
-                "SELECT node_json, uid FROM nodes
+                "SELECT node_json, uid, path FROM nodes
                  WHERE name LIKE ?1 ESCAPE '\\' AND trashed = 0 AND node_json IS NOT NULL
                  ORDER BY name LIMIT ?2",
             )?;
-            collect_pairs(stmt.query_map(params![pat, limit as i64], pair)?)?
+            collect_hits(stmt.query_map(params![pat, limit as i64], hit_row)?)?
         } else {
             // Escape double quotes and quote each term, then combine with AND so
             // all terms must match but can appear in any order or position.
@@ -356,18 +377,21 @@ impl Db {
                 .collect::<Vec<_>>()
                 .join(" AND ");
             let mut stmt = conn.prepare(
-                "SELECT n.node_json, n.uid
+                "SELECT n.node_json, n.uid, n.path
                  FROM nodes_fts f JOIN nodes n ON n.rowid = f.rowid
                  WHERE f.name MATCH ?1 AND n.trashed = 0 AND n.node_json IS NOT NULL
                  ORDER BY f.rank LIMIT ?2",
             )?;
-            collect_pairs(stmt.query_map(params![phrase, limit as i64], pair)?)?
+            collect_hits(stmt.query_map(params![phrase, limit as i64], hit_row)?)?
         };
 
         let mut hits = Vec::with_capacity(rows.len());
-        for (json, uid) in rows {
+        for (json, uid, path) in rows {
             let node: Node = serde_json::from_str(&json)?;
-            let path = path_of(&conn, &uid)?;
+            let path = match path {
+                Some(path) => path,
+                None => walk_path_of(&conn, &uid)?,
+            };
             hits.push(SearchHit { node, path });
         }
         Ok(hits)
@@ -382,54 +406,65 @@ impl Db {
         if query.is_empty() || limit == 0 {
             return Ok(Vec::new());
         }
-        let conn = self.conn.lock();
+        let conn = self.read();
         let terms = candidate_trigrams(query);
         let lane_limit = limit.div_ceil(2);
-        let mut rows: Vec<(String, String)> = if terms.is_empty() {
+        let mut rows: Vec<HitRow> = if terms.is_empty() {
             let pat = format!("%{}%", like_escape(query));
             let mut stmt = conn.prepare(
-                "SELECT node_json, uid FROM nodes
+                "SELECT node_json, uid, path FROM nodes
                  WHERE name LIKE ?1 ESCAPE '\\' AND trashed = 0 AND node_json IS NOT NULL
                  ORDER BY name LIMIT ?2",
             )?;
-            collect_pairs(stmt.query_map(params![pat, limit as i64], pair)?)?
+            collect_hits(stmt.query_map(params![pat, limit as i64], hit_row)?)?
         } else {
             let expression = terms.join(" OR ");
             let mut stmt = conn.prepare(
-                "SELECT n.node_json, n.uid
+                "SELECT n.node_json, n.uid, n.path
                    FROM nodes_fts f JOIN nodes n ON n.rowid = f.rowid
                   WHERE nodes_fts MATCH ?1 AND n.trashed = 0 AND n.node_json IS NOT NULL
                   ORDER BY f.rank LIMIT ?2",
             )?;
-            collect_pairs(stmt.query_map(params![expression, lane_limit as i64], pair)?)?
+            collect_hits(stmt.query_map(params![expression, lane_limit as i64], hit_row)?)?
         };
-        // A short substitution can destroy every trigram (`vedio` vs `video`).
-        // Feed the scorer an additional indexed same-initial lane so it can
-        // recover those candidates without scanning the full node table.
+        // Trigram rank does not know that a name *starts* with the query, and a
+        // short substitution can destroy every trigram outright (`vedio` vs
+        // `video`). Two indexed lanes cover both without scanning the node
+        // table: whole-query prefix first, then same-initial.
         if !terms.is_empty()
             && let Some(first) = query.chars().next()
         {
-            let prefix = format!("{}%", like_escape(&first.to_string()));
             let mut stmt = conn.prepare(
-                "SELECT node_json, uid FROM nodes
+                "SELECT node_json, uid, path FROM nodes
                  WHERE name COLLATE NOCASE LIKE ?1 ESCAPE '\\'
                    AND trashed = 0 AND node_json IS NOT NULL
                  ORDER BY name COLLATE NOCASE LIMIT ?2",
             )?;
-            let fallback =
-                collect_pairs(stmt.query_map(params![prefix, lane_limit as i64], pair)?)?;
-            for row in fallback {
-                if !rows.iter().any(|(_, uid)| uid == &row.1) {
+            let mut extra = Vec::new();
+            for pattern in [
+                format!("{}%", like_escape(query)),
+                format!("{}%", like_escape(&first.to_string())),
+            ] {
+                extra.extend(collect_hits(
+                    stmt.query_map(params![pattern, lane_limit as i64], hit_row)?,
+                )?);
+            }
+            let trigram = std::mem::take(&mut rows);
+            for row in extra.into_iter().chain(trigram) {
+                if !rows.iter().any(|(_, uid, _)| uid == &row.1) {
                     rows.push(row);
                 }
             }
             rows.truncate(limit);
         }
         rows.into_iter()
-            .map(|(json, uid)| {
+            .map(|(json, uid, path)| {
                 Ok(SearchHit {
                     node: serde_json::from_str(&json)?,
-                    path: path_of(&conn, &uid)?,
+                    path: match path {
+                        Some(path) => path,
+                        None => walk_path_of(&conn, &uid)?,
+                    },
                 })
             })
             .collect()
@@ -449,7 +484,7 @@ impl Db {
 
     /// Load every persisted node for cold-start hydration of the `State` maps.
     pub fn load_all(&self) -> Result<Vec<StoredNode>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt =
             conn.prepare("SELECT node_json, listed FROM nodes WHERE node_json IS NOT NULL")?;
         let rows = stmt.query_map([], |row| {
@@ -470,7 +505,7 @@ impl Db {
     /// 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.conn.lock();
+        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",
@@ -488,7 +523,7 @@ impl Db {
     /// 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.conn.lock();
+        let conn = self.read();
         let listed: Option<i64> = conn
             .query_row(
                 "SELECT listed FROM nodes WHERE uid = ?1",
@@ -521,13 +556,57 @@ impl Db {
     // in sync on every store/read/evict, so it is authoritative for eviction.
 }
 
+/// What a node's row looked like before this upsert, for the fields that decide
+/// whether the subtree below it has to be touched at all.
+struct PriorRow {
+    parent_uid: Option<String>,
+    name: String,
+    path: Option<String>,
+    trashed: bool,
+}
+
 fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
     let json = serde_json::to_string(node)?;
     let uid = node.uid.to_string();
+    let parent_uid = node.parent_uid.as_ref().map(|u| u.to_string());
+
+    let prior: Option<PriorRow> = tx
+        .query_row(
+            "SELECT parent_uid, name, path, trashed FROM nodes WHERE uid = ?1",
+            params![uid],
+            |row| {
+                Ok(PriorRow {
+                    parent_uid: row.get(0)?,
+                    name: row.get(1)?,
+                    path: row.get(2)?,
+                    trashed: row.get::<_, i64>(3)? != 0,
+                })
+            },
+        )
+        .optional()?;
+
+    // A node's path is its parent's path plus its own name — one indexed lookup,
+    // 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 {
+        None => String::new(),
+        Some(parent) => {
+            let parent_path: Option<Option<String>> = tx
+                .query_row(
+                    "SELECT path FROM nodes WHERE uid = ?1",
+                    params![parent],
+                    |row| row.get(0),
+                )
+                .optional()?;
+            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)
-         VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)
+           (uid, parent_uid, name, is_dir, size, mtime, trashed, node_json, path)
+         VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8, ?9)
          ON CONFLICT(uid) DO UPDATE SET
            parent_uid = excluded.parent_uid,
            name       = excluded.name,
@@ -535,59 +614,116 @@ fn upsert_node_tx(tx: &Transaction<'_>, node: &Node) -> Result<()> {
            size       = excluded.size,
            mtime      = excluded.mtime,
            trashed    = excluded.trashed,
-           node_json  = excluded.node_json",
+           node_json  = excluded.node_json,
+           path       = excluded.path",
         params![
             uid,
-            node.parent_uid.as_ref().map(|u| u.to_string()),
+            parent_uid,
             node.name,
             node.is_folder() as i64,
             node_size(node),
             node.modification_time,
             node.trashed as i64,
             json,
+            path,
         ],
     )?;
-    // FTS5 has no UPSERT. Folder moves also change every descendant path, so
-    // refresh the whole affected subtree while keeping rowid deletes indexed.
     let rowid: i64 = tx.query_row(
         "SELECT rowid FROM nodes WHERE uid = ?1",
         params![uid],
         |row| row.get(0),
     )?;
-    let mut affected = vec![rowid];
-    if node.is_folder() {
-        let mut stmt = tx.prepare(
-            "WITH RECURSIVE descendants(rowid, uid) AS (
-               SELECT rowid, uid FROM nodes WHERE parent_uid = ?1
-               UNION ALL
-               SELECT n.rowid, n.uid FROM nodes n
-                 JOIN descendants d ON n.parent_uid = d.uid
-             ) SELECT rowid FROM descendants",
-        )?;
-        for descendant in stmt.query_map(params![uid], |row| row.get(0))? {
-            affected.push(descendant?);
-        }
-    }
-    for affected_rowid in affected {
+
+    // FTS5 has no UPSERT, so the node's own row is always replaced.
+    let indexable = node_is_indexable_tx(tx, &uid)?;
+    tx.execute("DELETE FROM nodes_fts WHERE rowid = ?1", params![rowid])?;
+    if indexable {
         tx.execute(
-            "DELETE FROM nodes_fts WHERE rowid = ?1",
-            params![affected_rowid],
+            "INSERT INTO nodes_fts (rowid, name, path) VALUES (?1, ?2, ?3)",
+            params![rowid, node.name, path],
         )?;
-        let indexed: Option<(String, String)> = tx
-            .query_row(
-                "SELECT name, uid FROM nodes WHERE rowid = ?1",
-                params![affected_rowid],
-                |row| Ok((row.get(0)?, row.get(1)?)),
-            )
-            .optional()?;
-        if let Some((name, indexed_uid)) = indexed
-            && node_is_indexable_tx(tx, &indexed_uid)?
-        {
-            let path = path_of(tx, &indexed_uid)?;
-            tx.execute(
-                "INSERT INTO nodes_fts (rowid, name, path) VALUES (?1, ?2, ?3)",
-                params![affected_rowid, name, path],
-            )?;
+    }
+
+    // Everything below only matters when the subtree's paths or reachability
+    // actually moved. Re-listing a folder upserts it unchanged, and paying for a
+    // full descendant walk on each of those was most of what a large tree spent
+    // its time on.
+    let subtree_moved = prior.is_none_or(|prior| {
+        prior.parent_uid != parent_uid
+            || prior.name != node.name
+            || prior.path.as_deref() != Some(path.as_str())
+            || prior.trashed != node.trashed
+    });
+    if node.is_folder() && subtree_moved {
+        reindex_subtree_tx(tx, &uid, &path, indexable)?;
+    }
+    Ok(())
+}
+
+/// Rewrite every descendant's stored path and search-index row after `folder`
+/// moved, was renamed, or changed reachability.
+///
+/// One recursive walk carries both the new path and whether anything on the way
+/// down is trashed, so each descendant costs two trivial statements instead of a
+/// `path_of` walk plus an ancestor walk of its own. `folder_indexable` is the
+/// answer `node_is_indexable_tx` gave for the folder itself: what is above the
+/// subtree is the same for every node in it.
+///
+/// The depth cap is a liveness guard, not a policy: `UNION ALL` over a parent
+/// cycle (a's parent is b, b's parent is a — corrupt data, but the API can hand
+/// it to us) never terminates, and this runs inside the write transaction that
+/// holds the daemon's only SQLite connection. Real Drive trees are nowhere near
+/// this deep.
+fn reindex_subtree_tx(
+    tx: &Transaction<'_>,
+    folder: &str,
+    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 (
+               SELECT n.rowid, n.uid, n.name,
+                      CASE WHEN ?2 = '' THEN n.name ELSE ?2 || '/' || n.name END,
+                      n.trashed, 0
+                 FROM nodes n WHERE n.parent_uid = ?1
+               UNION ALL
+               SELECT n.rowid, n.uid, 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
+                WHERE sub.depth < 256
+             )
+             SELECT rowid, path, blocked FROM sub",
+        )?;
+        let rows = stmt.query_map(params![folder, folder_path], |row| {
+            Ok((
+                row.get::<_, i64>(0)?,
+                row.get::<_, String>(1)?,
+                row.get::<_, i64>(2)? != 0,
+            ))
+        })?;
+        let mut out = Vec::new();
+        for row in rows {
+            out.push(row?);
+        }
+        out
+    };
+    if descendants.is_empty() {
+        return Ok(());
+    }
+
+    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(
+        "INSERT INTO nodes_fts (rowid, name, path)
+         SELECT rowid, name, ?2 FROM nodes WHERE rowid = ?1",
+    )?;
+    for (rowid, path, blocked) in descendants {
+        set_path.execute(params![rowid, path])?;
+        unindex.execute(params![rowid])?;
+        if folder_indexable && !blocked {
+            index.execute(params![rowid, path])?;
         }
     }
     Ok(())
@@ -603,13 +739,27 @@ fn direct_child_uids_tx(tx: &Transaction<'_>, parent: &str) -> Result<Vec<String
     Ok(uids)
 }
 
+/// Whether a node belongs in the search index: it exists, and nothing on the
+/// way up to the top of its cached chain is trashed.
+///
+/// The chain does *not* have to reach a `parent_uid IS NULL` row. Only the My
+/// Files root is stored that way; a device folder's root lives in `device` /
+/// `sync_folder` and never gets a `nodes` row, so requiring a null-parent
+/// ancestor silently excluded every device-folder subtree from search — 29% of
+/// the nodes on the account this was found on. A subtree whose topmost cached
+/// row has an uncached parent is ordinary, reachable data.
+///
+/// What is still excluded is a *cycle*: the walk's own guard stops it, but
+/// [`path_of`] has no such guard, so an indexed cycle would hang a search. A
+/// clean chain ends at a row whose parent is null or simply not cached; a cycle
+/// 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, path) AS (
-           SELECT uid, parent_uid, trashed, char(31) || uid || char(31)
+        "WITH RECURSIVE ancestors(uid, parent_uid, trashed, depth, path) AS (
+           SELECT uid, parent_uid, trashed, 0, char(31) || uid || char(31)
              FROM nodes WHERE uid = ?1
            UNION ALL
-           SELECT n.uid, n.parent_uid, n.trashed,
+           SELECT n.uid, n.parent_uid, n.trashed, a.depth + 1,
                   a.path || n.uid || char(31)
              FROM ancestors a JOIN nodes n ON n.uid = a.parent_uid
             WHERE instr(a.path, char(31) || n.uid || char(31)) = 0
@@ -617,7 +767,12 @@ fn node_is_indexable_tx(tx: &Transaction<'_>, uid: &str) -> Result<bool> {
          SELECT CASE
            WHEN COUNT(*) = 0 THEN 0
            WHEN MAX(trashed) != 0 THEN 0
-           WHEN MAX(CASE WHEN parent_uid IS NULL THEN 1 ELSE 0 END) = 0 THEN 0
+           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.uid = a.parent_uid)
+           ) THEN 0
            ELSE 1
          END
          FROM ancestors",

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

@@ -119,15 +119,32 @@ pub struct PendingOp {
 }
 
 /// How much work the queue owes the server, by whether it carries bytes.
-#[derive(Debug, Clone, Copy, Default)]
+#[derive(Debug, Clone, Default)]
 pub struct PendingCounts {
     /// Queued `create`/`revision` ops: files whose content is not on the remote.
     pub uploads: i64,
     /// Queued `mkdir`/`rename`/`trash` ops: metadata the remote has not been
     /// told about.
     pub changes: i64,
+    /// Ops parked at [`PARK_UNTIL`]: a transient file's bytes, held back until
+    /// the rename that gives it its finished name. They are queued but will
+    /// never drain on their own, so counting them as "waiting to upload" would
+    /// have the front-end promise progress that is not coming.
+    pub parked: i64,
+    /// Ops that have failed at least [`FAILING_ATTEMPTS`] times. A permanently
+    /// failing op never wedges the queue — the backoff sees to that — which is
+    /// exactly why it needs surfacing: it retries forever, invisibly.
+    pub failing: i64,
+    /// The most recent error text from a failing op, for the front-end to show
+    /// instead of the bare count.
+    pub last_error: Option<String>,
 }
 
+/// Failed attempts after which an op is reported as failing rather than merely
+/// retrying. Six is where the backoff has reached its ceiling, so an op past it
+/// is retrying at the slowest rate it ever will and has been for minutes.
+pub const FAILING_ATTEMPTS: i64 = 6;
+
 /// The outcome of folding freshly written bytes into a queued create.
 #[derive(Debug, Clone)]
 pub struct AttachedBlob {
@@ -140,7 +157,7 @@ pub struct AttachedBlob {
 impl Db {
     /// Whether a specific desired-state operation is still queued for a node.
     pub fn has_pending_op(&self, uid: &str, kind: &str) -> Result<bool> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         conn.query_row(
             "SELECT EXISTS(
                 SELECT 1 FROM pending_op WHERE uid = ?1 AND kind = ?2
@@ -153,7 +170,7 @@ impl Db {
 
     /// Read an existing operation's metadata before a superseding enqueue.
     pub fn pending_op_meta(&self, uid: &str, kind: &str) -> Result<Option<String>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         conn.query_row(
             "SELECT meta_json FROM pending_op WHERE uid = ?1 AND kind = ?2",
             params![uid, kind],
@@ -352,7 +369,7 @@ impl Db {
 
     /// Check if a queued create or mkdir op exists for `uid`.
     pub fn has_create_op(&self, uid: &str) -> Result<bool> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let count: i64 = conn.query_row(
             "SELECT COUNT(*) FROM pending_op WHERE uid = ?1 AND kind IN (?2, ?3)",
             params![uid, OP_CREATE, OP_MKDIR],
@@ -368,7 +385,7 @@ impl Db {
     /// bytes are still owed an upload, and dropping it would discard the staged
     /// blob that holds them (`docs/BUGS.md` B71).
     pub fn has_any_op(&self, uid: &str) -> Result<bool> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let count: i64 = conn.query_row(
             "SELECT COUNT(*) FROM pending_op WHERE uid = ?1",
             params![uid],
@@ -464,7 +481,7 @@ impl Db {
     /// sort, and no separate index to maintain. The common case (something is
     /// due) exits on the first row.
     pub fn next_due_op(&self, now: i64) -> Result<Option<PendingOp>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare_cached(&format!(
             "SELECT id, kind, uid, parent_uid, name, blob_path, meta_json, created_at,
                     attempts, last_error, next_attempt_at
@@ -495,17 +512,115 @@ impl Db {
         Ok(op)
     }
 
+    /// Take the oldest due op for this worker, marking it claimed so no other
+    /// drain worker takes it, or `None` when there is nothing to do.
+    ///
+    /// The drain is several workers over one queue, which is only safe because
+    /// the claim is a column: a row is offered to exactly one worker, and the
+    /// worker that took it is the only one that may retire, defer or fail it.
+    ///
+    /// Two exclusions on top of [`next_due_op`](Self::next_due_op)'s:
+    ///
+    /// * `claimed_at = 0` — not already in flight somewhere else.
+    /// * no *other* claimed op shares this `uid`. Ordering only has to hold per
+    ///   node, but there it has to hold absolutely: a queued rename and a queued
+    ///   revision of one file must land in the order they were made, and two
+    ///   workers on one node would also race over its staged blob and its
+    ///   pending entry. `ORDER BY id` plus this exclusion gives per-uid serial
+    ///   order for free — the older op is claimed first and the newer one is
+    ///   invisible until it retires.
+    ///
+    /// Select and mark are one transaction, so two workers cannot both see the
+    /// row as unclaimed.
+    pub fn claim_next_due_op(&self, now: i64) -> Result<Option<PendingOp>> {
+        let mut conn = self.conn.lock();
+        let tx = conn.transaction()?;
+        let op = {
+            let mut stmt = tx.prepare_cached(&format!(
+                "SELECT id, kind, uid, parent_uid, name, blob_path, meta_json, created_at,
+                        attempts, last_error, next_attempt_at
+                 FROM pending_op
+                 WHERE next_attempt_at <= ?1
+                   AND claimed_at = 0
+                   AND (parent_uid IS NULL OR substr(parent_uid, 1, {n}) <> '{v}~')
+                   AND uid NOT IN (SELECT uid FROM pending_op WHERE claimed_at <> 0)
+                 ORDER BY id LIMIT 1",
+                v = LOCAL_VOLUME,
+                n = LOCAL_VOLUME.len() + 1,
+            ))?;
+            stmt.query_row(params![now], |r| {
+                Ok(PendingOp {
+                    id: r.get(0)?,
+                    kind: r.get(1)?,
+                    uid: r.get(2)?,
+                    parent_uid: r.get(3)?,
+                    name: r.get(4)?,
+                    blob_path: r.get(5)?,
+                    meta_json: r.get(6)?,
+                    created_at: r.get(7)?,
+                    attempts: r.get(8)?,
+                    last_error: r.get(9)?,
+                    next_attempt_at: r.get(10)?,
+                })
+            })
+            .optional()?
+        };
+        if let Some(op) = op.as_ref() {
+            tx.execute(
+                "UPDATE pending_op SET claimed_at = ?2 WHERE id = ?1",
+                params![op.id, now.max(1)],
+            )?;
+        }
+        tx.commit()?;
+        Ok(op)
+    }
+
+    /// Give a claimed op back to the queue, whatever became of the attempt.
+    ///
+    /// Called on every path out of a drain attempt rather than only the failing
+    /// ones: a handler that retires its own row leaves nothing to release (the
+    /// `UPDATE` matches nothing), and a handler that returns without retiring
+    /// *and* without failing would otherwise leave the row claimed by a worker
+    /// that has moved on — invisible to every worker, forever.
+    pub fn release_op_claim(&self, id: i64) -> Result<()> {
+        let conn = self.conn.lock();
+        conn.execute(
+            "UPDATE pending_op SET claimed_at = 0 WHERE id = ?1",
+            params![id],
+        )?;
+        Ok(())
+    }
+
+    /// Drop every claim in the table.
+    ///
+    /// A claim describes a worker in *this* process, so one surviving on disk
+    /// means the previous run died holding it. The single-writer lock
+    /// ([`Db::open`]) is what makes that inference safe: nobody else can be
+    /// draining this queue while we are opening it.
+    pub fn clear_op_claims(&self) -> Result<usize> {
+        let conn = self.conn.lock();
+        Ok(conn.execute(
+            "UPDATE pending_op SET claimed_at = 0 WHERE claimed_at <> 0",
+            [],
+        )?)
+    }
+
     /// The earliest `next_attempt_at` among all queued ops, or `None` if the
     /// queue is empty. Used by the drain loop to sleep exactly until the next
     /// debounced or backed-off op becomes eligible rather than waiting the full
     /// idle-poll interval.
+    ///
+    /// Claimed ops are excluded: another worker is already on them, so they are
+    /// not work this one is waiting for, and counting them would have an idle
+    /// worker spin on a row it cannot have.
     pub fn earliest_due_at(&self) -> Result<Option<i64>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let ts: Option<i64> = conn
             .query_row(
                 &format!(
                     "SELECT MIN(next_attempt_at) FROM pending_op \
-                     WHERE parent_uid IS NULL OR substr(parent_uid, 1, {n}) <> '{v}~'",
+                     WHERE claimed_at = 0 \
+                       AND (parent_uid IS NULL OR substr(parent_uid, 1, {n}) <> '{v}~')",
                     v = LOCAL_VOLUME,
                     n = LOCAL_VOLUME.len() + 1,
                 ),
@@ -520,7 +635,7 @@ impl Db {
     /// Every queued op, oldest first. For status read-outs and the CLI — the
     /// drain wants [`next_due_op`](Self::next_due_op) instead.
     pub fn pending_ops(&self) -> Result<Vec<PendingOp>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT id, kind, uid, parent_uid, name, blob_path, meta_json, created_at,
                     attempts, last_error, next_attempt_at
@@ -553,7 +668,7 @@ impl Db {
     /// mount owes the server, but it carries no bytes and reporting it as an
     /// upload is simply untrue.
     pub fn pending_op_counts(&self) -> Result<PendingCounts> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let uploads = conn.query_row(
             "SELECT COUNT(*) FROM pending_op WHERE kind IN (?1, ?2)",
             params![OP_REVISION, OP_CREATE],
@@ -564,7 +679,33 @@ impl Db {
             params![OP_REVISION, OP_CREATE],
             |r| r.get(0),
         )?;
-        Ok(PendingCounts { uploads, changes })
+        let parked = conn.query_row(
+            "SELECT COUNT(*) FROM pending_op WHERE next_attempt_at >= ?1",
+            params![PARK_UNTIL],
+            |r| r.get(0),
+        )?;
+        let failing = conn.query_row(
+            "SELECT COUNT(*) FROM pending_op WHERE attempts >= ?1",
+            params![FAILING_ATTEMPTS],
+            |r| r.get(0),
+        )?;
+        let last_error = conn
+            .query_row(
+                "SELECT last_error FROM pending_op
+                  WHERE attempts >= ?1 AND last_error IS NOT NULL
+                  ORDER BY attempts DESC LIMIT 1",
+                params![FAILING_ATTEMPTS],
+                |r| r.get::<_, Option<String>>(0),
+            )
+            .optional()?
+            .flatten();
+        Ok(PendingCounts {
+            uploads,
+            changes,
+            parked,
+            failing,
+            last_error,
+        })
     }
 
     /// Nothing bearing this volume may be handed to the API — it would 404. The
@@ -580,11 +721,16 @@ impl Db {
 
     /// Record a failed attempt and when to next try. Leaves the row in place —
     /// the staged bytes are still the only copy of the user's write.
+    ///
+    /// Clears any access-deferral window: whatever the op was waiting for has
+    /// now been reported, so the next uncleared deferral starts its own window
+    /// rather than escalating again on the following recheck.
     pub fn record_op_failure(&self, id: i64, error: &str, next_attempt_at: i64) -> Result<()> {
         let conn = self.conn.lock();
         conn.execute(
             "UPDATE pending_op
-             SET attempts = attempts + 1, last_error = ?2, next_attempt_at = ?3
+             SET attempts = attempts + 1, last_error = ?2, next_attempt_at = ?3,
+                 access_deferred_since = 0
              WHERE id = ?1",
             params![id, error, next_attempt_at],
         )?;
@@ -609,4 +755,132 @@ impl Db {
         )?;
         Ok(())
     }
+
+    /// Defer an op the local access check refused, and report how long it has
+    /// been refused for.
+    ///
+    /// Identical to [`defer_op_without_attempt`](Self::defer_op_without_attempt)
+    /// on the retry clock, plus the one thing that was missing: the first
+    /// deferral of a run stamps `access_deferred_since`, and every deferral
+    /// returns that stamp. A caller can therefore tell a deferral that is one
+    /// recheck old from one that has been repeating unchanged for days, which is
+    /// the difference between a permission the user is mid-way through changing
+    /// and a queue that will never drain.
+    ///
+    /// Returns the ms at which the current run of deferrals began — `now` on the
+    /// first one.
+    pub fn defer_op_for_access(&self, id: i64, now: i64, next_attempt_at: i64) -> Result<i64> {
+        let conn = self.conn.lock();
+        conn.execute(
+            "UPDATE pending_op
+             SET next_attempt_at = CASE
+                 WHEN next_attempt_at >= ?4 THEN next_attempt_at
+                 ELSE ?3
+             END,
+             access_deferred_since = CASE
+                 WHEN access_deferred_since = 0 THEN ?2
+                 ELSE access_deferred_since
+             END
+             WHERE id = ?1",
+            params![id, now, next_attempt_at, PARK_UNTIL],
+        )?;
+        let since = conn
+            .query_row(
+                "SELECT access_deferred_since FROM pending_op WHERE id = ?1",
+                params![id],
+                |r| r.get::<_, i64>(0),
+            )
+            .optional()?;
+        // A row that drained out from under this call leaves nothing to measure;
+        // reporting `now` says "this run just started", which is the reading that
+        // never escalates something that no longer exists.
+        Ok(since.filter(|since| *since != 0).unwrap_or(now))
+    }
+
+    /// Forget an op's access-deferral window, after an attempt the access check
+    /// let through. The op is no longer blocked, so a later deferral is the
+    /// start of a new run rather than the continuation of an old one.
+    pub fn clear_op_access_deferral(&self, id: i64) -> Result<()> {
+        let conn = self.conn.lock();
+        conn.execute(
+            "UPDATE pending_op SET access_deferred_since = 0
+             WHERE id = ?1 AND access_deferred_since <> 0",
+            params![id],
+        )?;
+        Ok(())
+    }
+
+    /// Every staged blob the queue still refers to.
+    ///
+    /// The startup staging reconcile subtracts this from what is actually in
+    /// `staging/`: the difference is bytes the kernel was told were written and
+    /// that nothing is going to upload.
+    pub fn op_blob_paths(&self) -> Result<std::collections::HashSet<String>> {
+        let conn = self.read();
+        let mut stmt =
+            conn.prepare("SELECT blob_path FROM pending_op WHERE blob_path IS NOT NULL")?;
+        let rows = stmt.query_map([], |r| r.get::<_, String>(0))?;
+        let mut out = std::collections::HashSet::new();
+        for row in rows {
+            out.insert(row?);
+        }
+        Ok(out)
+    }
+
+    /// Record that this daemon sealed `revision_id` on `uid`, and prune entries
+    /// past [`OWN_SEALED_TTL_MS`].
+    ///
+    /// One row per node, overwritten as the node advances. See
+    /// [`own_sealed_rev`](Self::own_sealed_rev) for what reads it.
+    pub fn set_own_sealed_rev(&self, uid: &str, revision_id: &str, now_ms: i64) -> Result<()> {
+        let conn = self.conn.lock();
+        conn.execute(
+            "INSERT INTO own_sealed_rev (uid, revision_id, sealed_at)
+             VALUES (?1, ?2, ?3)
+             ON CONFLICT(uid) DO UPDATE SET
+               revision_id = excluded.revision_id,
+               sealed_at   = excluded.sealed_at",
+            params![uid, revision_id, now_ms],
+        )?;
+        conn.execute(
+            "DELETE FROM own_sealed_rev WHERE sealed_at < ?1",
+            params![now_ms - OWN_SEALED_TTL_MS],
+        )?;
+        Ok(())
+    }
+
+    /// The last revision of `uid` this daemon sealed itself, if it is still
+    /// within [`OWN_SEALED_TTL_MS`].
+    ///
+    /// The drain asks before treating a moved-on remote as a conflict: a
+    /// revision we sealed means one writer stalled and resumed, which
+    /// supersedes rather than forking a `(sync-conflict)` copy (docs/BUGS.md
+    /// B70 layer B).
+    pub fn own_sealed_rev(&self, uid: &str, now_ms: i64) -> Result<Option<String>> {
+        let conn = self.read();
+        Ok(conn
+            .query_row(
+                "SELECT revision_id FROM own_sealed_rev
+                  WHERE uid = ?1 AND sealed_at >= ?2",
+                params![uid, now_ms - OWN_SEALED_TTL_MS],
+                |r| r.get(0),
+            )
+            .optional()?)
+    }
+
+    /// Forget what we sealed on `uid` — it has been trashed, so there is no
+    /// revision left to chain onto.
+    pub fn clear_own_sealed_rev(&self, uid: &str) -> Result<()> {
+        let conn = self.conn.lock();
+        conn.execute("DELETE FROM own_sealed_rev WHERE uid = ?1", params![uid])?;
+        Ok(())
+    }
 }
+
+/// How long a revision this daemon sealed stays recognisable as its own.
+///
+/// Bounds a table that would otherwise grow with every write for the life of
+/// the install. A week is far longer than any stall→resume — a browser download
+/// that pauses and continues, an editor that reopens its handle — and short
+/// enough that the table tracks recent work rather than accumulating history.
+pub const OWN_SEALED_TTL_MS: i64 = 7 * 24 * 60 * 60 * 1000;

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

@@ -115,7 +115,7 @@ impl Db {
         range: Option<(i64, i64)>,
         favorites: bool,
     ) -> Result<Vec<StoredPhoto>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         // Built up so any combination of the optional filters is one indexed
         // query rather than a statement per case.
         let mut sql = String::from(
@@ -174,7 +174,7 @@ impl Db {
         &self,
         kind: Option<crate::control::PhotoKind>,
     ) -> Result<Vec<(i32, i32, usize)>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let (filter, binds): (&str, Vec<i64>) = match kind {
             Some(k) => (" WHERE kind = ?1", vec![k.as_i64()]),
             None => ("", Vec::new()),
@@ -201,7 +201,7 @@ impl Db {
     /// Per-tab counts for the Photos page subtitle: `(photos, videos, raw)`.
     pub fn photos_counts(&self) -> Result<(usize, usize, usize)> {
         use crate::control::PhotoKind;
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare("SELECT kind, COUNT(*) FROM photos GROUP BY kind")?;
         let rows = stmt.query_map([], |r| Ok((r.get::<_, i64>(0)?, r.get::<_, i64>(1)?)))?;
         let (mut photos, mut videos, mut raw) = (0usize, 0usize, 0usize);
@@ -223,7 +223,7 @@ impl Db {
         if uids.is_empty() {
             return Ok(Vec::new());
         }
-        let conn = self.conn.lock();
+        let conn = self.read();
         let placeholders = vec!["?"; uids.len()].join(",");
         let mut stmt = conn.prepare(&format!(
             "SELECT uid, capture_time, name, ratio, thumb_state, kind, favorite FROM photos
@@ -273,7 +273,7 @@ impl Db {
 
     /// Number of photos in the persisted timeline.
     pub fn photos_count(&self) -> Result<usize> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let n: i64 = conn.query_row("SELECT COUNT(*) FROM photos", [], |r| r.get(0))?;
         Ok(n.max(0) as usize)
     }

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

@@ -4,8 +4,21 @@
 use rusqlite::{OptionalExtension, params};
 
 use super::Db;
+use super::utils::MAX_PATH_DEPTH;
 use crate::Result;
 
+/// One row of [`Db::pin_list`]. `recursive` is pin *policy* — whether the whole
+/// subtree is kept — while `is_dir` is the node's kind as the node cache knows
+/// it, or `None` for a pin whose node is not cached. Reading the former as the
+/// latter is what made a non-recursively pinned folder render as a file.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct PinRow {
+    pub uid: String,
+    pub path: String,
+    pub recursive: bool,
+    pub is_dir: Option<bool>,
+}
+
 impl Db {
     pub fn pin_add(&self, uid: &str, path: &str, recursive: bool) -> Result<()> {
         let conn = self.conn.lock();
@@ -25,16 +38,23 @@ impl Db {
         Ok(n > 0)
     }
 
-    /// Every directly-pinned entry `(uid, path, recursive)`, ordered by uid.
-    pub fn pin_list(&self) -> Result<Vec<(String, String, bool)>> {
-        let conn = self.conn.lock();
-        let mut stmt = conn.prepare("SELECT uid, path, recursive FROM pins ORDER BY uid")?;
+    /// Every directly-pinned entry, ordered by uid.
+    pub fn pin_list(&self) -> Result<Vec<PinRow>> {
+        let conn = self.read();
+        // `recursive` is pin policy; the node's kind comes from `nodes`, and is
+        // NULL for a pin whose node was never cached.
+        let mut stmt = conn.prepare(
+            "SELECT p.uid, p.path, p.recursive, n.is_dir
+               FROM pins p LEFT JOIN nodes n ON n.uid = p.uid
+              ORDER BY p.uid",
+        )?;
         let rows = stmt.query_map([], |r| {
-            Ok((
-                r.get::<_, String>(0)?,
-                r.get::<_, String>(1)?,
-                r.get::<_, i64>(2)? != 0,
-            ))
+            Ok(PinRow {
+                uid: r.get(0)?,
+                path: r.get(1)?,
+                recursive: r.get::<_, i64>(2)? != 0,
+                is_dir: r.get::<_, Option<i64>>(3)?.map(|is_dir| is_dir != 0),
+            })
         })?;
         let mut out = Vec::new();
         for r in rows {
@@ -47,8 +67,13 @@ impl Db {
     /// is pinned recursively. The ancestor check walks `parent_uid` 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`
+    /// 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.
     pub fn is_pinned(&self, uid: &str) -> Result<bool> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let direct: Option<i64> = conn
             .query_row("SELECT 1 FROM pins WHERE uid = ?1", params![uid], |r| {
                 r.get(0)
@@ -59,14 +84,18 @@ impl Db {
         }
         let anc: Option<i64> = conn
             .query_row(
-                "WITH RECURSIVE anc(uid, parent_uid) AS (
-                   SELECT uid, parent_uid FROM nodes WHERE uid = ?1
-                   UNION ALL
-                   SELECT n.uid, n.parent_uid FROM nodes n JOIN anc ON n.uid = anc.parent_uid
-                 )
-                 SELECT 1 FROM anc a JOIN pins p ON p.uid = a.uid
-                 WHERE a.uid != ?1 AND p.recursive = 1
-                 LIMIT 1",
+                &format!(
+                    "WITH RECURSIVE anc(uid, parent_uid, depth) AS (
+                       SELECT uid, parent_uid, 0 FROM nodes WHERE uid = ?1
+                       UNION ALL
+                       SELECT n.uid, n.parent_uid, anc.depth + 1
+                       FROM nodes n JOIN anc ON n.uid = anc.parent_uid
+                       WHERE anc.depth < {MAX_PATH_DEPTH}
+                     )
+                     SELECT 1 FROM anc a JOIN pins p ON p.uid = a.uid
+                     WHERE a.uid != ?1 AND p.recursive = 1
+                     LIMIT 1"
+                ),
                 params![uid],
                 |r| r.get(0),
             )
@@ -78,7 +107,7 @@ impl Db {
     /// every descendant of a recursively-pinned folder. Used to build the
     /// eviction-exempt set (the budget enforcer hashes these into cache keys).
     pub fn pinned_uids(&self) -> Result<Vec<String>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "WITH RECURSIVE sub(uid) AS (
                SELECT uid FROM pins WHERE recursive = 1
@@ -100,7 +129,7 @@ impl Db {
     /// Every descendant uid of `folder` (all depths), via a `parent_uid` 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.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "WITH RECURSIVE sub(uid) AS (
                SELECT uid FROM nodes WHERE parent_uid = ?1

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

@@ -16,7 +16,7 @@ impl Db {
     /// remains the restart/offline authority and every explicit role change is
     /// written through before this cache is updated.
     pub fn all_share_access(&self) -> Result<HashMap<NodeUid, Access>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare("SELECT root_uid, access FROM share_access")?;
         let rows = stmt.query_map([], |row| {
             Ok((row.get::<_, String>(0)?, row.get::<_, String>(1)?))
@@ -42,7 +42,7 @@ impl Db {
 
     /// Read the effective access recorded for a shared-tree root.
     pub fn share_access(&self, uid: &NodeUid) -> Result<Option<Access>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let value = conn
             .query_row(
                 "SELECT access FROM share_access WHERE root_uid = ?1",
@@ -96,7 +96,7 @@ impl Db {
     /// share root. `None` means the node itself is not persisted, which callers
     /// must not treat as owned: stale handles need to fail closed.
     pub fn effective_node_access(&self, uid: &NodeUid) -> Result<Option<Access>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let exists: bool = conn.query_row(
             "SELECT EXISTS(SELECT 1 FROM nodes WHERE uid = ?1)",
             [uid.to_string()],

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

@@ -8,7 +8,7 @@ use crate::Result;
 
 impl Db {
     pub fn get_event_cursor(&self) -> Result<Option<String>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let v = conn
             .query_row(
                 "SELECT value FROM sync_state WHERE key = 'event_cursor'",
@@ -32,7 +32,7 @@ impl Db {
 
     /// Read a `sync_state` value as a string.
     pub fn state_str(&self, key: &str) -> Result<Option<String>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let v = conn
             .query_row(
                 "SELECT value FROM sync_state WHERE key = ?1",
@@ -66,7 +66,7 @@ impl Db {
     /// dropping it would leave a file that exists nowhere but this machine with
     /// nothing left to create it. (Writes to a node that is itself still queued
     pub fn state_i64(&self, key: &str) -> Result<Option<i64>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let v: Option<String> = conn
             .query_row(
                 "SELECT value FROM sync_state WHERE key = ?1",

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

@@ -35,6 +35,14 @@ pub struct StoredSyncEntry {
     pub remote_uid: Option<String>,
     pub local_mtime: i64,
     pub local_size: i64,
+    /// The same modification time to nanosecond precision, when it is known.
+    ///
+    /// `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
+    /// 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>,
     pub remote_rev: Option<String>,
     pub remote_hash: Option<String>,
 }
@@ -57,7 +65,7 @@ impl Db {
 
     /// Every synced folder, oldest first.
     pub fn sync_folder_list(&self) -> Result<Vec<StoredSyncFolder>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT id, local_path, remote_uid, remote_share_id, mode, pending_mode, state, last_sync
              FROM sync_folder ORDER BY id",
@@ -83,7 +91,7 @@ impl Db {
 
     /// Look up one synced folder by id.
     pub fn sync_folder_get(&self, id: i64) -> Result<Option<StoredSyncFolder>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         conn.query_row(
             "SELECT id, local_path, remote_uid, remote_share_id, mode, pending_mode, state, last_sync
              FROM sync_folder WHERE id = ?1",
@@ -166,9 +174,10 @@ impl Db {
 
     /// The whole per-file sync baseline for a folder, keyed by relative path.
     pub fn sync_entries(&self, folder_id: i64) -> Result<HashMap<String, StoredSyncEntry>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
-            "SELECT rel_path, remote_uid, local_mtime, local_size, remote_rev, remote_hash
+            "SELECT rel_path, remote_uid, local_mtime, local_size, remote_rev, remote_hash,
+                    local_mtime_ns
              FROM sync_entry WHERE folder_id = ?1",
         )?;
         let rows = stmt.query_map(params![folder_id], |r| {
@@ -179,6 +188,7 @@ impl Db {
                 local_size: r.get(3)?,
                 remote_rev: r.get(4)?,
                 remote_hash: r.get(5)?,
+                local_mtime_ns: r.get(6)?,
             })
         })?;
         let mut map = HashMap::new();
@@ -196,7 +206,7 @@ impl Db {
     /// `sync_folder` and descendants come from the last successful
     /// `sync_entry` baseline.
     pub fn mirror_contains_uid(&self, uid: &str) -> Result<bool> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         conn.query_row(
             "SELECT EXISTS(
                  SELECT 1
@@ -216,14 +226,16 @@ impl Db {
         let conn = self.conn.lock();
         conn.execute(
             "INSERT INTO sync_entry
-               (folder_id, rel_path, remote_uid, local_mtime, local_size, remote_rev, remote_hash)
-             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7)
+               (folder_id, rel_path, remote_uid, local_mtime, local_size, remote_rev,
+                remote_hash, local_mtime_ns)
+             VALUES (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)
              ON CONFLICT(folder_id, rel_path) DO UPDATE SET
-               remote_uid  = excluded.remote_uid,
-               local_mtime = excluded.local_mtime,
-               local_size  = excluded.local_size,
-               remote_rev  = excluded.remote_rev,
-               remote_hash = excluded.remote_hash",
+               remote_uid     = excluded.remote_uid,
+               local_mtime    = excluded.local_mtime,
+               local_size     = excluded.local_size,
+               remote_rev     = excluded.remote_rev,
+               remote_hash    = excluded.remote_hash,
+               local_mtime_ns = excluded.local_mtime_ns",
             params![
                 folder_id,
                 e.rel_path,
@@ -232,6 +244,7 @@ impl Db {
                 e.local_size,
                 e.remote_rev,
                 e.remote_hash,
+                e.local_mtime_ns,
             ],
         )?;
         Ok(())

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

@@ -867,6 +867,67 @@ fn shared_root_pinned_name_survives_database_reopen() {
     let _ = std::fs::remove_file(path);
 }
 
+/// Two writers on one database is the failure mode the single-instance lock
+/// exists to prevent — a hand-run `pdfs mount` next to the systemd unit gives
+/// two daemons the same inode space, content cache, and drain queue. The second
+/// open has to fail, and it has to stop failing once the first handle is gone.
+#[test]
+fn a_second_writer_is_refused_while_the_first_holds_the_database() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-single-writer-{}-{}.db",
+        std::process::id(),
+        now_test_id()
+    ));
+    let first = Db::open(&path).unwrap();
+    let second = Db::open(&path);
+    assert!(second.is_err(), "a second writer was allowed in");
+
+    drop(first);
+    // The lock lives in the kernel and dies with the descriptor, so nothing has
+    // to be cleaned up for the next daemon to start.
+    Db::open(&path).expect("reopen after the first handle is dropped");
+
+    let _ = std::fs::remove_file(&path);
+    let _ = std::fs::remove_file(path.with_extension("db.lock"));
+}
+
+/// `cache.db` is derived state — every row can be re-fetched or re-scanned — so
+/// a file that is not a database at all must not stop the daemon starting. It
+/// is moved aside (not deleted: it is the only evidence) and rebuilt.
+#[test]
+fn a_corrupt_database_is_moved_aside_and_rebuilt() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-corrupt-{}-{}.db",
+        std::process::id(),
+        now_test_id()
+    ));
+    std::fs::write(&path, b"this is not an SQLite database").unwrap();
+
+    let db = Db::open(&path).unwrap();
+    db.set_state_str("shared_with_me_name", "rebuilt").unwrap();
+    assert_eq!(
+        db.state_str("shared_with_me_name").unwrap().as_deref(),
+        Some("rebuilt")
+    );
+    drop(db);
+
+    let dir = path.parent().unwrap();
+    let stem = path.file_name().unwrap().to_string_lossy().to_string();
+    let quarantined: Vec<_> = std::fs::read_dir(dir)
+        .unwrap()
+        .filter_map(|e| e.ok())
+        .map(|e| e.file_name().to_string_lossy().to_string())
+        .filter(|name| name.starts_with(&format!("{stem}.corrupt-")))
+        .collect();
+    assert_eq!(quarantined.len(), 1, "the damaged file was not kept");
+
+    for name in quarantined {
+        let _ = std::fs::remove_file(dir.join(name));
+    }
+    let _ = std::fs::remove_file(&path);
+    let _ = std::fs::remove_file(path.with_extension("db.lock"));
+}
+
 fn local(path: &str, name: &str, is_dir: bool) -> LocalEntry {
     LocalEntry {
         path: path.into(),
@@ -911,6 +972,25 @@ fn local_scan_indexes_then_prunes_stale_paths() {
     assert_eq!(db.search_local("notes", 10).unwrap().len(), 1);
 }
 
+/// The index is maintained incrementally rather than rebuilt at the end of a
+/// scan, so the case that used to be covered for free — a file the scan sees
+/// again — needs its own test: a re-scan must neither lose the entry nor
+/// duplicate it.
+#[test]
+fn rescanning_an_unchanged_file_keeps_exactly_one_index_entry() {
+    let db = Db::open_in_memory().unwrap();
+    for (generation, mtime) in [(1_000, 5), (2_000, 9)] {
+        let g = db.local_begin_scan().unwrap();
+        let mut e = local("/home/u/docs/report.pdf", "report.pdf", false);
+        e.mtime = mtime;
+        db.local_upsert_batch(g, &[e]).unwrap();
+        assert_eq!(db.local_finish_scan(g, generation).unwrap(), 1);
+        let hits = db.search_local("report", 10).unwrap();
+        assert_eq!(hits.len(), 1, "generation {generation}");
+        assert_eq!(hits[0].mtime, mtime);
+    }
+}
+
 /// Queries below the trigram minimum still match, via the `LIKE` fallback.
 #[test]
 fn local_search_short_query_like_fallback() {
@@ -989,6 +1069,62 @@ fn search_excludes_trashed_and_respects_limit() {
     assert_eq!(db.search("alph", 1).unwrap().len(), 1);
 }
 
+/// A device folder's root is stored in `device`/`sync_folder`, never in
+/// `nodes`, so its children's `parent_uid` points at a row that does not exist.
+/// Requiring the ancestor walk to reach a `parent_uid IS NULL` row therefore
+/// excluded every device-folder subtree from search: 2,705 of 9,252 nodes on
+/// the account this was found on, including everything under `~/Downloads`.
+#[test]
+fn search_finds_nodes_below_an_uncached_parent() {
+    let db = Db::open_in_memory().unwrap();
+    // "device-root" is deliberately never upserted.
+    db.upsert_node(&folder("downloads", Some("device-root"), "Downloads"))
+        .unwrap();
+    db.upsert_node(&file("t", "downloads", "tickets.pdf", 1))
+        .unwrap();
+
+    let hits = db.search("tickets", 10).unwrap();
+    assert_eq!(hits.len(), 1, "a device folder's files must be searchable");
+    assert_eq!(hits[0].path, "Downloads/tickets.pdf");
+}
+
+/// The relaxed rule must not also start indexing trash: a node whose *parent*
+/// is trashed stays out even though the walk now terminates happily.
+#[test]
+fn search_excludes_a_node_under_a_trashed_ancestor() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    let mut folder_gone = folder("boxed", Some("root"), "Boxed");
+    folder_gone.trashed = true;
+    db.upsert_node(&folder_gone).unwrap();
+    db.upsert_node(&file("f1", "boxed", "buried.txt", 1))
+        .unwrap();
+
+    assert!(db.search("buried", 10).unwrap().is_empty());
+}
+
+/// A parent cycle is corrupt data the API can still hand us. It must stay out
+/// of the index, and — because the short-query `LIKE` lane reads `nodes`
+/// directly and never consults the index — resolving one's path must terminate
+/// rather than spin inside the daemon's only SQLite connection.
+#[test]
+fn a_parent_cycle_is_unindexed_and_never_hangs_a_search() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("a", Some("b"), "Alphaville"))
+        .unwrap();
+    db.upsert_node(&folder("b", Some("a"), "Betamax")).unwrap();
+
+    // Index lane: the cycle is not indexed, so it cannot be found.
+    assert!(db.search("alphaville", 10).unwrap().is_empty());
+    assert!(db.search("betamax", 10).unwrap().is_empty());
+
+    // LIKE lane (below the trigram minimum): the rows are reachable, and what
+    // matters is that resolving their paths returns at all.
+    let hits = db.search("al", 10).unwrap();
+    assert_eq!(hits.len(), 1);
+    assert!(hits[0].path.ends_with("Alphaville"));
+}
+
 #[test]
 fn search_short_query_like_fallback() {
     let db = Db::open_in_memory().unwrap();
@@ -1373,6 +1509,7 @@ fn migration_v17_adds_share_access_to_a_v16_fixture() {
              DROP TABLE albums;
              DROP INDEX idx_photos_favorite;
              ALTER TABLE photos DROP COLUMN favorite;
+             ALTER TABLE nodes DROP COLUMN path;
              UPDATE sync_state SET value = '16' WHERE key = 'schema_version';",
         )
         .unwrap();
@@ -1758,6 +1895,123 @@ fn failed_superseding_insert_keeps_the_old_pending_op() {
     assert_eq!(ops[0].blob_path.as_deref(), Some("/staging/original"));
 }
 
+/// B53's remaining half. The insert-failure regression above proves the *row*
+/// rolls back; this proves the two things that make the rollback usable — the
+/// old blob is not reported as superseded (so the caller does not delete the
+/// bytes the surviving row still points at), and the rollback survives a
+/// restart rather than living only in the connection that failed.
+#[test]
+fn a_rolled_back_supersede_keeps_its_blob_and_survives_reopen() {
+    let dir = std::env::temp_dir().join(format!("pdfs-db-b53-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    std::fs::create_dir_all(&dir).unwrap();
+    let path = dir.join("queue.sqlite");
+    let op = |blob: &str| PendingOp {
+        id: 0,
+        kind: OP_REVISION.to_string(),
+        uid: uid("durable").to_string(),
+        parent_uid: None,
+        name: None,
+        blob_path: Some(blob.to_string()),
+        meta_json: Some("{}".to_string()),
+        created_at: 1,
+        attempts: 0,
+        last_error: None,
+        next_attempt_at: 0,
+    };
+
+    {
+        let db = Db::open(&path).unwrap();
+        db.enqueue_op(&op("/staging/original")).unwrap();
+        db.with_conn(|conn| {
+            conn.execute_batch(
+                "CREATE TRIGGER reject_replacement BEFORE INSERT ON pending_op
+                 WHEN NEW.blob_path = '/staging/replacement'
+                 BEGIN SELECT RAISE(ABORT, 'injected insert failure'); END;",
+            )?;
+            Ok(())
+        })
+        .unwrap();
+
+        // The failure must not hand back the old blob path. That value is the
+        // caller's instruction to delete those bytes, and the row that owns
+        // them is still queued.
+        assert!(db.enqueue_op(&op("/staging/replacement")).is_err());
+        db.with_conn(|conn| {
+            conn.execute_batch("DROP TRIGGER reject_replacement")?;
+            Ok(())
+        })
+        .unwrap();
+    }
+
+    let db = Db::open(&path).unwrap();
+    let ops = db.pending_ops().unwrap();
+    assert_eq!(ops.len(), 1, "old or new — never neither");
+    assert_eq!(ops[0].blob_path.as_deref(), Some("/staging/original"));
+
+    // And once the injected failure is gone, superseding works and *does*
+    // report the blob it retired.
+    let (_, superseded) = db.enqueue_op(&op("/staging/replacement")).unwrap();
+    assert_eq!(superseded.as_deref(), Some("/staging/original"));
+    assert_eq!(db.pending_ops().unwrap().len(), 1);
+
+    drop(db);
+    std::fs::remove_dir_all(&dir).unwrap();
+}
+
+/// A full disk, as SQLite reports it. `max_page_count` makes the database
+/// refuse to grow, which is the same `SQLITE_FULL` an out-of-space filesystem
+/// produces — and the queue must come out of it with the acknowledged work
+/// still in it (B53).
+#[test]
+fn a_full_database_rolls_the_supersede_back_rather_than_erasing_it() {
+    let db = Db::open_in_memory().unwrap();
+    let op = |blob: &str| PendingOp {
+        id: 0,
+        kind: OP_REVISION.to_string(),
+        uid: uid("full").to_string(),
+        parent_uid: None,
+        name: None,
+        blob_path: Some(blob.to_string()),
+        meta_json: Some("{}".to_string()),
+        created_at: 1,
+        attempts: 0,
+        last_error: None,
+        next_attempt_at: 0,
+    };
+    db.enqueue_op(&op("/staging/original")).unwrap();
+
+    // Cap the file at its current size, so any page the insert needs fails.
+    let pages: i64 = db
+        .with_conn(|conn| Ok(conn.query_row("PRAGMA page_count", [], |r| r.get(0))?))
+        .unwrap();
+    db.with_conn(|conn| {
+        conn.execute_batch(&format!("PRAGMA max_page_count = {pages}"))?;
+        Ok(())
+    })
+    .unwrap();
+
+    // A payload far larger than one page, so growth is unavoidable.
+    let mut fat = op("/staging/replacement");
+    fat.meta_json = Some("x".repeat(512 * 1024));
+    let result = db.enqueue_op(&fat);
+
+    db.with_conn(|conn| {
+        conn.execute_batch("PRAGMA max_page_count = 1073741823")?;
+        Ok(())
+    })
+    .unwrap();
+
+    assert!(result.is_err(), "a database that cannot grow must refuse");
+    let ops = db.pending_ops().unwrap();
+    assert_eq!(ops.len(), 1);
+    assert_eq!(
+        ops[0].blob_path.as_deref(),
+        Some("/staging/original"),
+        "the acknowledged upload is still queued and still owns its bytes"
+    );
+}
+
 #[test]
 fn atomic_trash_replacement_returns_owned_blobs_after_commit() {
     let db = Db::open_in_memory().unwrap();
@@ -2271,6 +2525,7 @@ fn mirror_uid_lookup_covers_the_root_and_synced_descendants_only() {
             local_size: 2,
             remote_rev: Some("3".into()),
             remote_hash: Some("2".into()),
+            local_mtime_ns: None,
         },
     )
     .unwrap();
@@ -2287,6 +2542,7 @@ fn mirror_uid_lookup_covers_the_root_and_synced_descendants_only() {
             local_size: 2,
             remote_rev: Some("3".into()),
             remote_hash: Some("2".into()),
+            local_mtime_ns: None,
         },
     )
     .unwrap();
@@ -2472,14 +2728,41 @@ fn pin_add_list_remove_roundtrip() {
     db.pin_add("vol~d", "docs", true).unwrap();
     let list = db.pin_list().unwrap();
     assert_eq!(list.len(), 2);
-    assert_eq!(list[0], ("vol~a".into(), "docs/a.txt".into(), false));
-    assert_eq!(list[1], ("vol~d".into(), "docs".into(), true));
+    // No `nodes` row for either pin, so the kind is unknown rather than guessed
+    // from the recursive flag.
+    assert_eq!(
+        list[0],
+        PinRow {
+            uid: "vol~a".into(),
+            path: "docs/a.txt".into(),
+            recursive: false,
+            is_dir: None,
+        }
+    );
+    assert_eq!(
+        list[1],
+        PinRow {
+            uid: "vol~d".into(),
+            path: "docs".into(),
+            recursive: true,
+            is_dir: None,
+        }
+    );
+
+    // Once the node is cached, the pin reports the real kind — a folder pinned
+    // non-recursively must not look like a file.
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&folder("d", Some("root"), "docs")).unwrap();
+    db.pin_add("vol~d", "docs", false).unwrap();
+    let list = db.pin_list().unwrap();
+    assert!(!list[1].recursive, "pin policy stays non-recursive");
+    assert_eq!(list[1].is_dir, Some(true), "but the node is still a folder");
 
     // Re-pin refreshes path/flag, not a duplicate row.
     db.pin_add("vol~a", "moved/a.txt", false).unwrap();
     let list = db.pin_list().unwrap();
     assert_eq!(list.len(), 2);
-    assert_eq!(list[0].1, "moved/a.txt");
+    assert_eq!(list[0].path, "moved/a.txt");
 
     assert!(db.pin_remove("vol~a").unwrap());
     assert!(!db.pin_remove("vol~a").unwrap());
@@ -2545,6 +2828,26 @@ fn non_recursive_folder_pin_does_not_cover_children() {
     assert!(!db.is_pinned(&du("rep")).unwrap());
 }
 
+/// A `parent_uid` cycle is corrupt data the API can hand us, and `is_pinned`'s
+/// ancestor walk is `UNION ALL` — uncapped it never terminates, while holding
+/// the daemon's only SQLite connection, on a path that runs per cached read.
+/// The answer here matters less than the fact that there is one.
+#[test]
+fn is_pinned_terminates_on_a_parent_cycle() {
+    let db = Db::open_in_memory().unwrap();
+    let du = |l: &str| uid(l).to_string();
+    // a -> b -> a, with nothing pinned above either.
+    db.upsert_node(&folder("a", Some("b"), "A")).unwrap();
+    db.upsert_node(&folder("b", Some("a"), "B")).unwrap();
+    db.upsert_node(&file("leaf", "a", "leaf.txt", 1)).unwrap();
+
+    assert!(!db.is_pinned(&du("leaf")).unwrap());
+
+    // And a pin *inside* the cycle is still found rather than walked past.
+    db.pin_add(&du("a"), "A", true).unwrap();
+    assert!(db.is_pinned(&du("leaf")).unwrap());
+}
+
 #[test]
 fn schema_objects_exist() {
     let db = Db::open_in_memory().unwrap();
@@ -3099,3 +3402,502 @@ fn clear_state_prefix_takes_only_the_prefixed_keys() {
         "the listing's own stamp is not a per-album one"
     );
 }
+
+// --- `nodes.path`, and the subtree work it replaces (DB3) -------------------
+
+/// Read the stored path column directly: the point of these tests is that the
+/// column itself is right, not that `path_of` can still fall back to a walk.
+fn stored_path(db: &Db, link: &str) -> Option<String> {
+    use rusqlite::OptionalExtension;
+    db.with_conn(|conn| {
+        Ok(conn
+            .query_row(
+                "SELECT path FROM nodes WHERE uid = ?1",
+                [uid(link).to_string()],
+                |row| row.get::<_, Option<String>>(0),
+            )
+            .optional()?
+            .flatten())
+    })
+    .unwrap()
+}
+
+#[test]
+fn a_node_stores_its_path_when_it_is_written() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&folder("docs", Some("root"), "Documents"))
+        .unwrap();
+    db.upsert_node(&file("f1", "docs", "report.pdf", 1))
+        .unwrap();
+
+    // The root's name is the mount, so it contributes nothing.
+    assert_eq!(stored_path(&db, "root").as_deref(), Some(""));
+    assert_eq!(stored_path(&db, "docs").as_deref(), Some("Documents"));
+    assert_eq!(
+        stored_path(&db, "f1").as_deref(),
+        Some("Documents/report.pdf")
+    );
+}
+
+#[test]
+fn a_node_below_an_uncached_parent_starts_its_own_path() {
+    // A device folder's root lives in `device`/`sync_folder` and never gets a
+    // `nodes` row, so its children are the top of the cached chain.
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("orphan", Some("never-cached"), "Work"))
+        .unwrap();
+    db.upsert_node(&file("f1", "orphan", "notes.txt", 1))
+        .unwrap();
+
+    assert_eq!(stored_path(&db, "orphan").as_deref(), Some("Work"));
+    assert_eq!(stored_path(&db, "f1").as_deref(), Some("Work/notes.txt"));
+}
+
+#[test]
+fn renaming_a_folder_rewrites_every_descendant_path() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&folder("a", Some("root"), "Before"))
+        .unwrap();
+    db.upsert_node(&folder("b", Some("a"), "Inner")).unwrap();
+    db.upsert_node(&file("f1", "b", "deep.txt", 1)).unwrap();
+    assert_eq!(
+        stored_path(&db, "f1").as_deref(),
+        Some("Before/Inner/deep.txt")
+    );
+
+    db.upsert_node(&folder("a", Some("root"), "After")).unwrap();
+
+    assert_eq!(stored_path(&db, "a").as_deref(), Some("After"));
+    assert_eq!(stored_path(&db, "b").as_deref(), Some("After/Inner"));
+    assert_eq!(
+        stored_path(&db, "f1").as_deref(),
+        Some("After/Inner/deep.txt")
+    );
+    let hit = &db.search("deep.txt", 10).unwrap()[0];
+    assert_eq!(
+        hit.path, "After/Inner/deep.txt",
+        "the search index must carry the rewritten path too"
+    );
+}
+
+#[test]
+fn moving_a_folder_rewrites_every_descendant_path() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&folder("old", Some("root"), "Old")).unwrap();
+    db.upsert_node(&folder("new", Some("root"), "New")).unwrap();
+    db.upsert_node(&folder("moved", Some("old"), "Moved"))
+        .unwrap();
+    db.upsert_node(&file("f1", "moved", "deep.txt", 1)).unwrap();
+
+    db.upsert_node(&folder("moved", Some("new"), "Moved"))
+        .unwrap();
+
+    assert_eq!(stored_path(&db, "moved").as_deref(), Some("New/Moved"));
+    assert_eq!(
+        stored_path(&db, "f1").as_deref(),
+        Some("New/Moved/deep.txt")
+    );
+}
+
+#[test]
+fn trashing_a_folder_drops_its_subtree_from_the_index() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&folder("a", Some("root"), "Holder"))
+        .unwrap();
+    db.upsert_node(&file("f1", "a", "hidden.txt", 1)).unwrap();
+    assert_eq!(db.search("hidden", 10).unwrap().len(), 1);
+
+    let mut trashed = folder("a", Some("root"), "Holder");
+    trashed.trashed = true;
+    db.upsert_node(&trashed).unwrap();
+
+    assert_eq!(
+        db.search("hidden", 10).unwrap().len(),
+        0,
+        "a file under a trashed folder is not reachable and must not be findable"
+    );
+
+    // …and comes back when the folder does.
+    db.upsert_node(&folder("a", Some("root"), "Holder"))
+        .unwrap();
+    assert_eq!(db.search("hidden", 10).unwrap().len(), 1);
+}
+
+/// The re-listing case, which is most of what the write path actually does: a
+/// folder upserted with the same name and parent must not touch its subtree.
+///
+/// Written as a ratio between two subtree sizes, so it fails on the scaling
+/// regression rather than on a slow machine. Before this, every re-listing paid
+/// a `path_of` walk plus an ancestor walk per descendant.
+#[test]
+fn re_listing_a_folder_does_not_scale_with_its_subtree() {
+    fn elapsed_for(children: usize) -> std::time::Duration {
+        let db = Db::open_in_memory().unwrap();
+        db.upsert_node(&folder("root", None, "My Files")).unwrap();
+        db.upsert_node(&folder("big", Some("root"), "Big")).unwrap();
+        let kids: Vec<Node> = (0..children)
+            .map(|i| file(&format!("k{i}"), "big", &format!("child-{i}.txt"), 1))
+            .collect();
+        db.upsert_nodes(&kids).unwrap();
+
+        let unchanged = folder("big", Some("root"), "Big");
+        let start = std::time::Instant::now();
+        for _ in 0..20 {
+            db.upsert_node(&unchanged).unwrap();
+        }
+        start.elapsed()
+    }
+
+    let small = elapsed_for(100);
+    let large = elapsed_for(2_000);
+    assert!(
+        large < small * 8,
+        "re-listing a folder scaled with its subtree: {small:?} for 100 children, \
+         {large:?} for 2000 (20x the descendants)"
+    );
+}
+
+#[test]
+fn migration_v25_backfills_paths_for_an_existing_tree() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-db-v24-fixture-{}-{}.db",
+        std::process::id(),
+        std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos()
+    ));
+    {
+        let db = Db::open(&path).unwrap();
+        db.upsert_node(&folder("root", None, "My Files")).unwrap();
+        db.upsert_node(&folder("docs", Some("root"), "Documents"))
+            .unwrap();
+        db.upsert_node(&file("f1", "docs", "report.pdf", 1))
+            .unwrap();
+        db.upsert_node(&folder("orphan", Some("never-cached"), "Work"))
+            .unwrap();
+        db.upsert_node(&file("f2", "orphan", "notes.txt", 1))
+            .unwrap();
+    }
+    {
+        // Put the file back in the state a released V24 database was in.
+        let conn = rusqlite::Connection::open(&path).unwrap();
+        conn.execute_batch(
+            "ALTER TABLE nodes DROP COLUMN path;
+             UPDATE sync_state SET value = '24' WHERE key = 'schema_version';",
+        )
+        .unwrap();
+    }
+
+    let db = Db::open(&path).unwrap();
+    assert_eq!(stored_path(&db, "root").as_deref(), Some(""));
+    assert_eq!(stored_path(&db, "docs").as_deref(), Some("Documents"));
+    assert_eq!(
+        stored_path(&db, "f1").as_deref(),
+        Some("Documents/report.pdf"),
+        "an existing tree must come out of the migration with the same paths \
+         the walk used to produce"
+    );
+    // A subtree whose top has an uncached parent is ordinary data, not an error.
+    assert_eq!(stored_path(&db, "orphan").as_deref(), Some("Work"));
+    assert_eq!(stored_path(&db, "f2").as_deref(), Some("Work/notes.txt"));
+
+    let _ = std::fs::remove_file(&path);
+    let _ = std::fs::remove_file(format!("{}.lock", path.display()));
+}
+
+/// A queue carried over from V26 keeps its rows, and every one of them starts
+/// out not access-deferred — a migration must not invent a deferral window that
+/// would report an ordinary queued upload as blocked.
+#[test]
+fn migration_v27_adds_the_access_deferral_column_to_a_v26_queue() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-db-v26-fixture-{}-{}.db",
+        std::process::id(),
+        std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos()
+    ));
+    {
+        let db = Db::open(&path).unwrap();
+        db.enqueue_op(&crate::db::PendingOp {
+            id: 0,
+            kind: crate::db::OP_REVISION.to_string(),
+            uid: "v~l".to_string(),
+            parent_uid: None,
+            name: None,
+            blob_path: Some("/tmp/blob".to_string()),
+            meta_json: Some("{}".to_string()),
+            created_at: 1,
+            attempts: 0,
+            last_error: None,
+            next_attempt_at: 0,
+        })
+        .unwrap();
+    }
+    {
+        // Put the file back in the state a released V26 database was in.
+        let conn = rusqlite::Connection::open(&path).unwrap();
+        conn.execute_batch(
+            "ALTER TABLE pending_op DROP COLUMN access_deferred_since;
+             UPDATE sync_state SET value = '26' WHERE key = 'schema_version';",
+        )
+        .unwrap();
+    }
+
+    let db = Db::open(&path).unwrap();
+    let ops = db.pending_ops().unwrap();
+    assert_eq!(ops.len(), 1, "the migration keeps the queued write");
+    let now = 5_000i64;
+    assert_eq!(
+        db.defer_op_for_access(ops[0].id, now, now + 5_000).unwrap(),
+        now,
+        "a carried-over op is not already deferred"
+    );
+
+    let _ = std::fs::remove_file(&path);
+    let _ = std::fs::remove_file(format!("{}.lock", path.display()));
+}
+
+/// A mirror baseline carried over from V27 keeps its rows, and each one reads
+/// back with no nanosecond time. That `None` is the whole point: it makes the
+/// comparison fall back to whole seconds for rows written before the column
+/// existed, instead of asserting a sub-second time of zero and re-uploading
+/// every already-synced file in the folder (bugs.md B25).
+#[test]
+fn migration_v28_adds_sub_second_local_times_without_disturbing_a_v27_baseline() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-db-v27-fixture-{}-{}.db",
+        std::process::id(),
+        std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos()
+    ));
+    {
+        let db = Db::open(&path).unwrap();
+        let folder = db
+            .sync_folder_add("/home/me/Mirror", "vol~root", "share")
+            .unwrap();
+        db.sync_entry_upsert(
+            folder,
+            &StoredSyncEntry {
+                rel_path: "notes.txt".into(),
+                remote_uid: Some("vol~notes".into()),
+                local_mtime: 1_700_000_000,
+                local_mtime_ns: Some(1_700_000_000_123_456_789),
+                local_size: 42,
+                remote_rev: Some("1700000000".into()),
+                remote_hash: Some("42".into()),
+            },
+        )
+        .unwrap();
+    }
+    {
+        // Put the file back in the state a released V27 database was in.
+        let conn = rusqlite::Connection::open(&path).unwrap();
+        conn.execute_batch(
+            "ALTER TABLE sync_entry DROP COLUMN local_mtime_ns;
+             UPDATE sync_state SET value = '27' WHERE key = 'schema_version';",
+        )
+        .unwrap();
+    }
+
+    let db = Db::open(&path).unwrap();
+    let entries = db.sync_entries(1).unwrap();
+    let entry = entries.get("notes.txt").expect("the baseline row survives");
+    assert_eq!(entry.local_mtime, 1_700_000_000);
+    assert_eq!(entry.local_size, 42);
+    assert_eq!(
+        entry.local_mtime_ns, None,
+        "a carried-over row must not claim a sub-second time it never recorded"
+    );
+
+    // And the column is live: a refreshed row keeps the precision it is given.
+    db.sync_entry_upsert(
+        1,
+        &StoredSyncEntry {
+            local_mtime_ns: Some(1_700_000_001_000_000_500),
+            ..entry.clone()
+        },
+    )
+    .unwrap();
+    assert_eq!(
+        db.sync_entries(1).unwrap()["notes.txt"].local_mtime_ns,
+        Some(1_700_000_001_000_000_500)
+    );
+
+    let _ = std::fs::remove_file(&path);
+    let _ = std::fs::remove_file(format!("{}.lock", path.display()));
+}
+
+// --- read-only connection pool (DB2) ---------------------------------------
+
+/// A read must not queue behind whatever happens to be writing.
+///
+/// The write connection is held for the whole measurement — which is what a
+/// large listing's commit does to it — while a reader asks for a search. Before
+/// the pool this was the same mutex, so the read waited for the writer;
+/// `busy_timeout` never entered into it, because the contention was this
+/// process's own lock rather than SQLite's.
+#[test]
+fn a_read_does_not_wait_for_the_write_connection() {
+    let path = std::env::temp_dir().join(format!(
+        "pdfs-db-readpool-{}-{}.db",
+        std::process::id(),
+        std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos()
+    ));
+    let db = std::sync::Arc::new(Db::open(&path).unwrap());
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.upsert_node(&file("f1", "root", "findme.txt", 1))
+        .unwrap();
+
+    let held = std::time::Duration::from_millis(500);
+    let (tx, rx) = std::sync::mpsc::channel();
+    let writer = {
+        let db = db.clone();
+        std::thread::spawn(move || {
+            db.with_conn(|_conn| {
+                tx.send(()).unwrap();
+                std::thread::sleep(held);
+                Ok(())
+            })
+            .unwrap();
+        })
+    };
+    rx.recv().unwrap();
+
+    let start = std::time::Instant::now();
+    let hits = db.search("findme", 10).unwrap();
+    let waited = start.elapsed();
+    writer.join().unwrap();
+
+    assert_eq!(hits.len(), 1, "the read must still see committed data");
+    assert!(
+        waited < held / 2,
+        "the read waited {waited:?} for a write connection held {held:?}"
+    );
+
+    drop(db);
+    let _ = std::fs::remove_file(&path);
+    let _ = std::fs::remove_file(format!("{}.lock", path.display()));
+}
+
+/// §5: the drain is several workers over one queue, and the claim column is the
+/// only thing keeping them off each other's work. Two properties matter — no
+/// row is ever handed to two workers, and no *node* is ever worked by two
+/// workers even though its ops are separate rows.
+#[test]
+fn a_claimed_op_is_invisible_to_every_other_worker() {
+    let db = Db::open_in_memory().unwrap();
+    let root = uid("root").to_string();
+    for i in 0..3 {
+        db.enqueue_op(&bulk_op(i, &root)).unwrap();
+    }
+
+    let first = db.claim_next_due_op(10).unwrap().expect("an op is due");
+    let second = db
+        .claim_next_due_op(10)
+        .unwrap()
+        .expect("another op is due");
+    let third = db
+        .claim_next_due_op(10)
+        .unwrap()
+        .expect("a third op is due");
+    assert!(
+        db.claim_next_due_op(10).unwrap().is_none(),
+        "a fourth claim must find nothing left: every queued op is taken"
+    );
+
+    let mut ids = [first.id, second.id, third.id];
+    ids.sort_unstable();
+    assert_eq!(
+        ids,
+        [1, 2, 3],
+        "each worker must get a distinct row, oldest first"
+    );
+
+    // Releasing puts one back, and it is the one that comes out next.
+    db.release_op_claim(second.id).unwrap();
+    let again = db.claim_next_due_op(10).unwrap().expect("the released op");
+    assert_eq!(again.id, second.id);
+}
+
+#[test]
+fn two_workers_never_share_a_node() {
+    let db = Db::open_in_memory().unwrap();
+    let root = uid("root").to_string();
+    // Two ops of different kinds against one node — a queued rename and a
+    // queued revision, which is an ordinary `mv` plus a save.
+    let mut revision = bulk_op(0, &root);
+    revision.parent_uid = None;
+    db.enqueue_op(&revision).unwrap();
+    let rename = PendingOp {
+        kind: OP_RENAME.to_string(),
+        parent_uid: Some(root.clone()),
+        blob_path: None,
+        meta_json: None,
+        ..bulk_op(0, &root)
+    };
+    db.enqueue_op(&rename).unwrap();
+
+    let claimed = db.claim_next_due_op(10).unwrap().expect("an op is due");
+    assert_eq!(claimed.kind, OP_REVISION, "the older op goes first");
+    assert!(
+        db.claim_next_due_op(10).unwrap().is_none(),
+        "the second op targets the same node, so it must wait for the first: \
+         two workers on one uid would race over its staged blob and land its \
+         changes out of order"
+    );
+
+    db.release_op_claim(claimed.id).unwrap();
+    db.delete_op(claimed.id).unwrap();
+    assert_eq!(
+        db.claim_next_due_op(10).unwrap().map(|o| o.kind),
+        Some(OP_RENAME.to_string()),
+        "once the revision retires, the rename is claimable"
+    );
+}
+
+#[test]
+fn claims_do_not_survive_the_process_that_took_them() {
+    let db = Db::open_in_memory().unwrap();
+    let root = uid("root").to_string();
+    for i in 0..2 {
+        db.enqueue_op(&bulk_op(i, &root)).unwrap();
+    }
+    db.claim_next_due_op(10).unwrap().unwrap();
+    db.claim_next_due_op(10).unwrap().unwrap();
+    assert!(db.claim_next_due_op(10).unwrap().is_none());
+
+    // What `Db::open` does after the single-writer lock says the previous run
+    // is gone. Without it those ops are invisible to every worker forever.
+    assert_eq!(db.clear_op_claims().unwrap(), 2);
+    assert!(
+        db.claim_next_due_op(10).unwrap().is_some(),
+        "a crashed run's claims must not park its queue"
+    );
+}
+
+#[test]
+fn an_idle_worker_does_not_wait_on_an_op_another_worker_has() {
+    let db = Db::open_in_memory().unwrap();
+    let root = uid("root").to_string();
+    db.enqueue_op(&bulk_op(0, &root)).unwrap();
+
+    assert_eq!(db.earliest_due_at().unwrap(), Some(0));
+    db.claim_next_due_op(10).unwrap().unwrap();
+    assert_eq!(
+        db.earliest_due_at().unwrap(),
+        None,
+        "an op somebody else is draining is not work this worker is waiting for"
+    );
+}

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

@@ -39,7 +39,7 @@ impl Db {
     /// The persisted trash listing, folders first then by name — the order the
     /// Trash page shows it in.
     pub fn trash_list(&self) -> Result<Vec<StoredTrash>> {
-        let conn = self.conn.lock();
+        let conn = self.read();
         let mut stmt = conn.prepare(
             "SELECT uid, name, is_dir, size, mtime FROM trash
              ORDER BY is_dir DESC, name COLLATE NOCASE",

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

@@ -1,6 +1,6 @@
 //! Small query helpers shared across the table modules.
 
-use rusqlite::{Connection, params};
+use rusqlite::{Connection, OptionalExtension, params};
 
 use crate::Result;
 
@@ -8,14 +8,19 @@ use crate::Result;
 /// grams), so short queries fall back to a `LIKE` scan over `nodes.name`.
 pub(super) const TRIGRAM_MIN: usize = 3;
 
-pub(super) fn pair(row: &rusqlite::Row) -> rusqlite::Result<(String, String)> {
-    Ok((row.get(0)?, row.get(1)?))
+/// One raw search row: the node's JSON, its uid, and its stored path — `None`
+/// only for a row written before the `path` column existed, which
+/// [`path_of`] repairs by walking.
+pub(super) type HitRow = (String, String, Option<String>);
+
+pub(super) fn hit_row(row: &rusqlite::Row) -> rusqlite::Result<HitRow> {
+    Ok((row.get(0)?, row.get(1)?, row.get(2)?))
 }
 
-/// Drain a `query_map` of [`pair`] rows into a `Vec`, propagating row errors.
-pub(super) fn collect_pairs(
-    rows: impl Iterator<Item = rusqlite::Result<(String, String)>>,
-) -> Result<Vec<(String, String)>> {
+/// Drain a `query_map` of [`hit_row`] rows into a `Vec`, propagating row errors.
+pub(super) fn collect_hits(
+    rows: impl Iterator<Item = rusqlite::Result<HitRow>>,
+) -> Result<Vec<HitRow>> {
     let mut out = Vec::new();
     for r in rows {
         out.push(r?);
@@ -31,19 +36,58 @@ pub(super) fn like_escape(s: &str) -> String {
         .replace('_', "\\_")
 }
 
-/// Resolve a node's mountpoint-relative path by walking `parent_uid` to the
-/// root via a recursive CTE. The root (the node with no parent) is excluded, so
-/// a top-level file `report.pdf` yields `"report.pdf"`, not `"My Files/report.pdf"`.
+/// How deep the parent walk may go before it gives up. Real Drive trees are
+/// nowhere near this; a parent *cycle* is unbounded, and this query is on the
+/// path of every search result, including the `LIKE` lane that reads `nodes`
+/// directly and so never passed through the index's cycle check.
+pub(super) const MAX_PATH_DEPTH: usize = 256;
+
+/// Append `name` to a parent's stored path. An empty parent path is the root,
+/// whose name is the mount and so contributes nothing.
+pub(super) fn join_path(parent_path: &str, name: &str) -> String {
+    if parent_path.is_empty() {
+        name.to_string()
+    } else {
+        format!("{parent_path}/{name}")
+    }
+}
+
+/// Resolve a node's mountpoint-relative path. The root (the node with no
+/// parent) is excluded, so a top-level file `report.pdf` yields
+/// `"report.pdf"`, not `"My Files/report.pdf"`.
+///
+/// Reads the stored `nodes.path`, which the write path maintains (see
+/// `upsert_node_tx`). Falls back to [`walk_path_of`] for a row that predates the
+/// column or was never written through — a search serving a keystroke used to
+/// run that walk once per candidate, which is the reason the column exists.
 pub(super) fn path_of(conn: &Connection, uid: &str) -> Result<String> {
-    let mut stmt = conn.prepare(
+    let stored: Option<Option<String>> = conn
+        .query_row("SELECT path FROM nodes WHERE uid = ?1", params![uid], |r| {
+            r.get(0)
+        })
+        .optional()?;
+    match stored.flatten() {
+        Some(path) => Ok(path),
+        None => walk_path_of(conn, uid),
+    }
+}
+
+/// Resolve a path by walking `parent_uid` to the root via a recursive CTE.
+///
+/// A cycle in `parent_uid` 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 (
            SELECT uid, parent_uid, name, 0 FROM nodes WHERE uid = ?1
            UNION ALL
            SELECT n.uid, n.parent_uid, n.name, anc.depth + 1
            FROM nodes n JOIN anc ON n.uid = anc.parent_uid
+           WHERE anc.depth < {MAX_PATH_DEPTH}
          )
-         SELECT name, parent_uid FROM anc ORDER BY depth DESC",
-    )?;
+         SELECT name, parent_uid FROM anc ORDER BY depth DESC"
+    ))?;
     let rows = stmt.query_map(params![uid], |r| {
         Ok((r.get::<_, String>(0)?, r.get::<_, Option<String>>(1)?))
     })?;

crates/pdfs-core/src/error.rs

@@ -45,6 +45,27 @@ pub enum Error {
     Other(String),
 }
 
+impl Error {
+    /// Whether this is the local disk being full (`ENOSPC`), as opposed to any
+    /// other I/O failure.
+    ///
+    /// Worth distinguishing because it is the one storage failure the user can
+    /// act on, and because the caller's response differs: a full disk is met by
+    /// evicting cached blobs and answering `ENOSPC`, where `EIO` would read as a
+    /// broken file. `std::io::ErrorKind::StorageFull` is still unstable, so this
+    /// compares the raw code.
+    pub fn is_disk_full(&self) -> bool {
+        match self {
+            Error::Io(e) => e.raw_os_error() == Some(libc::ENOSPC),
+            // SQLite reports it as its own code rather than surfacing the errno.
+            Error::Db(rusqlite::Error::SqliteFailure(e, _)) => {
+                e.code == rusqlite::ErrorCode::DiskFull
+            }
+            _ => false,
+        }
+    }
+}
+
 pub type Result<T> = std::result::Result<T, Error>;
 
 /// A failure on its way to a front-end: prose for the user, plus the

crates/pdfs-core/src/lib.rs

@@ -20,6 +20,7 @@ pub mod search;
 pub mod service;
 pub mod shell;
 pub mod syncignore;
+pub mod takeout;
 
 pub use access::{Access, access_for, perm_bits};
 pub use error::{CoreError, CoreResult, Error, Result};

crates/pdfs-core/src/localindex.rs

@@ -26,10 +26,20 @@ const SKIP_DIRS: &[&str] = &[
     "venv",
     ".venv",
     "vendor",
+    "dist",
     "dist-newstyle",
+    "build",
     "Trash",
 ];
 
+/// Directory *paths* skipped when they end with one of these, for caches whose
+/// own name is too generic to blacklist (`mod`). The Go module cache was 63,399
+/// of the 110,187 entries indexed on the machine this was measured on — 58% of
+/// the index, crowding real files out of the bounded candidate pool the fuzzy
+/// scorer draws from. The other big dependency caches (`.cargo`, `.rustup`,
+/// `.gradle`, `.m2`) are already skipped by the hidden-file filter.
+const SKIP_PATH_SUFFIXES: &[&str] = &["go/pkg/mod"];
+
 /// Hard cap on indexed entries, so a pathological home directory cannot grow the
 /// database without bound. Reaching it stops the walk early.
 const MAX_ENTRIES: usize = 400_000;
@@ -90,7 +100,10 @@ pub fn scan(
             if excludes.iter().any(|e| path.starts_with(e)) {
                 return false;
             }
-            !matches!(entry.file_name().to_str(), Some(name) if SKIP_DIRS.contains(&name))
+            if matches!(entry.file_name().to_str(), Some(name) if SKIP_DIRS.contains(&name)) {
+                return false;
+            }
+            !is_skipped_path(path)
         });
 
     let state = parking_lot::Mutex::new(SinkState {
@@ -150,6 +163,17 @@ impl<F: FnMut(Vec<LocalEntry>)> SinkState<F> {
     }
 }
 
+/// Whether `path` is (or is inside) one of the [`SKIP_PATH_SUFFIXES`] caches.
+/// Matched on the path's own components so a directory merely *named* `mod`
+/// keeps being indexed.
+fn is_skipped_path(path: &Path) -> bool {
+    let path = path.to_string_lossy();
+    SKIP_PATH_SUFFIXES.iter().any(|suffix| {
+        path.strip_suffix(suffix)
+            .is_some_and(|head| head.is_empty() || head.ends_with('/'))
+    })
+}
+
 /// Convert a walker entry into a [`LocalEntry`], reusing the metadata the walker
 /// already fetched. Entries with non-UTF-8 paths are dropped: the index (and the
 /// JSON wire format) is UTF-8 only.
@@ -221,4 +245,27 @@ mod tests {
 
         std::fs::remove_dir_all(&tmp).unwrap();
     }
+
+    /// The Go module cache is the single largest source of index noise on a
+    /// developer's machine (58% of the entries on the one this was measured
+    /// on), and it cannot be pruned by directory name: `mod` is far too
+    /// common a name to blacklist outright.
+    #[test]
+    fn the_go_module_cache_is_pruned_but_a_plain_mod_dir_is_not() {
+        let tmp = std::env::temp_dir().join(format!("pdfs-scan-gomod-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&tmp);
+        std::fs::create_dir_all(tmp.join("go/pkg/mod/example.com/lib")).unwrap();
+        std::fs::create_dir_all(tmp.join("kernel/mod")).unwrap();
+        std::fs::write(tmp.join("go/pkg/mod/example.com/lib/vendored.go"), b"x").unwrap();
+        std::fs::write(tmp.join("kernel/mod/mine.conf"), b"x").unwrap();
+
+        let mut got = Vec::new();
+        scan(std::slice::from_ref(&tmp), &[], |batch| got.extend(batch));
+
+        let names: Vec<&str> = got.iter().map(|e| e.name.as_str()).collect();
+        assert!(!names.contains(&"vendored.go"), "{names:?}");
+        assert!(names.contains(&"mine.conf"), "{names:?}");
+
+        std::fs::remove_dir_all(&tmp).unwrap();
+    }
 }

crates/pdfs-core/src/takeout.rs

@@ -0,0 +1,887 @@
+//! Reading a Google Photos **Takeout** export: what is in the archives, which
+//! album each photo belongs to, and when it was taken.
+//!
+//! This module is pure structure — it opens the archives' central directories
+//! and reads the small JSON sidecars, never the media bytes. The import itself
+//! (hashing, duplicate detection, upload, album creation) lives in the daemon;
+//! everything here is offline-testable and has no Proton dependency.
+//!
+//! # What a Takeout export looks like
+//!
+//! Google splits an export into numbered zips (`takeout-20260817T...-001.zip`,
+//! `-002.zip`, …) that are *independent* archives — no zip64 spanning — but a
+//! photo and its JSON sidecar can land in different parts, and one album's
+//! folder can be spread over several. So the scan treats the whole set as one
+//! namespace keyed by the path inside the export:
+//!
+//! ```text
+//! Takeout/Google Photos/Iceland 2019/IMG_0042.jpg
+//! Takeout/Google Photos/Iceland 2019/IMG_0042.jpg.supplemental-metadata.json
+//! Takeout/Google Photos/Iceland 2019/metadata.json        <- album title
+//! Takeout/Google Photos/Photos from 2019/IMG_0043.jpg     <- no album
+//! Takeout/Google Photos/Trash/IMG_0044.jpg                <- skipped
+//! ```
+//!
+//! The service folder (`Google Photos`) is localized, as are the year folders
+//! (`Photos from 2019`) and the trash folder, so nothing here matches on the
+//! service name: the first component is dropped when it is the export root, the
+//! second is the service, and the rest is `<folder>/<file>`. A folder is an
+//! **album** when it carries an album metadata sidecar naming it; anything else
+//! is a plain bucket that imports into the timeline only. Trash is matched by
+//! name against [`TRASH_FOLDERS`] — the one place a localized name is
+//! unavoidable, because a trashed photo is not marked as such anywhere else.
+
+use std::collections::{BTreeMap, HashMap};
+use std::io::Read;
+use std::path::{Path, PathBuf};
+
+use serde::{Deserialize, Serialize};
+
+use crate::error::{CoreError, CoreResult};
+
+/// Folder names Google uses for the trash bucket, lowercased. A Takeout export
+/// only contains one when the user asked for it, and its photos are deleted —
+/// importing them would resurrect them, so they are skipped.
+///
+/// Localized, and necessarily incomplete: a locale not listed here imports its
+/// trash as ordinary timeline photos. Extend as reports come in rather than
+/// guessing at transliterations.
+pub const TRASH_FOLDERS: &[&str] = &[
+    "trash",
+    "bin",
+    "papierkorb",
+    "corbeille",
+    "papelera",
+    "papelera de reciclaje",
+    "cestino",
+    "lixeira",
+    "prullenbak",
+    "kosz",
+    "koš",
+    "skräpkorgen",
+    "papperskorg",
+    "papirkurv",
+    "roskakori",
+    "kuka",
+    "回收站",
+    "回收筒",
+    "ゴミ箱",
+    "휴지통",
+    "корзина",
+    "кошик",
+    "çöp kutusu",
+    "σκουπίδια",
+];
+
+/// Sidecar file names that describe the *folder* (its album title) rather than
+/// one photo, lowercased. Google has renamed this file more than once.
+const ALBUM_METADATA_NAMES: &[&str] = &[
+    "metadata.json",
+    "album-metadata.json",
+    "print-subscriptions.json",
+    "shared_album_comments.json",
+    "user-generated-memory-titles.json",
+];
+
+/// The suffix Google appends to a photo's sidecar, lowercased. Truncation means
+/// only a *prefix* of it may survive (see [`strip_sidecar_suffix`]).
+const SUPPLEMENTAL: &str = ".supplemental-metadata";
+
+/// File extensions imported as photos or videos. Anything else in the export —
+/// `archive_browser.html`, `.csv` activity logs, `print-subscriptions.json` —
+/// is not media and is ignored.
+const MEDIA_EXTENSIONS: &[(&str, &str)] = &[
+    ("jpg", "image/jpeg"),
+    ("jpeg", "image/jpeg"),
+    ("png", "image/png"),
+    ("gif", "image/gif"),
+    ("webp", "image/webp"),
+    ("bmp", "image/bmp"),
+    ("tif", "image/tiff"),
+    ("tiff", "image/tiff"),
+    ("heic", "image/heic"),
+    ("heif", "image/heif"),
+    ("avif", "image/avif"),
+    ("dng", "image/x-adobe-dng"),
+    ("cr2", "image/x-canon-cr2"),
+    ("cr3", "image/x-canon-cr3"),
+    ("nef", "image/x-nikon-nef"),
+    ("arw", "image/x-sony-arw"),
+    ("orf", "image/x-olympus-orf"),
+    ("rw2", "image/x-panasonic-rw2"),
+    ("raf", "image/x-fuji-raf"),
+    ("mp4", "video/mp4"),
+    ("m4v", "video/x-m4v"),
+    ("mov", "video/quicktime"),
+    ("avi", "video/x-msvideo"),
+    ("mkv", "video/x-matroska"),
+    ("webm", "video/webm"),
+    ("3gp", "video/3gpp"),
+    ("mts", "video/mp2t"),
+    ("m2ts", "video/mp2t"),
+    ("mpg", "video/mpeg"),
+    ("mpeg", "video/mpeg"),
+];
+
+/// The media type for `name`'s extension, or `None` when it is not media this
+/// import handles.
+pub fn media_type_of(name: &str) -> Option<&'static str> {
+    let ext = Path::new(name)
+        .extension()
+        .and_then(|e| e.to_str())?
+        .to_ascii_lowercase();
+    MEDIA_EXTENSIONS
+        .iter()
+        .find(|(candidate, _)| *candidate == ext)
+        .map(|(_, media_type)| *media_type)
+}
+
+/// Where a photo sits in the export, which decides whether it joins an album.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub enum Bucket {
+    /// A named album folder — the photo joins that album *and* the timeline.
+    Album(String),
+    /// A year folder (`Photos from 2019`) or the export root: timeline only.
+    Timeline,
+    /// The archive bucket: timeline only, like Google shows it.
+    Archived,
+}
+
+/// One media file found in the export.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct TakeoutPhoto {
+    /// Index into the archive list the scan was given.
+    pub archive: usize,
+    /// The entry's full path inside that archive — how the importer reopens it.
+    pub entry: String,
+    /// The name to upload under: the sidecar's `title` when it has one (Google
+    /// mangles long names on disk but keeps the original there), else the file
+    /// name on disk.
+    pub name: String,
+    /// Uncompressed size in bytes, from the zip's central directory.
+    pub size: u64,
+    /// Media type from the extension.
+    pub media_type: String,
+    /// Capture time in epoch seconds, from `photoTakenTime` (falling back to
+    /// `creationTime`). `None` when the photo has no sidecar — the upload then
+    /// defaults it to now, as the SDK does.
+    pub capture_time: Option<i64>,
+    /// The sidecar's `favorited` flag.
+    pub favorite: bool,
+    /// Which bucket the file was found in.
+    pub bucket: Bucket,
+}
+
+/// Everything one scan found, ready to be turned into an import plan.
+#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
+pub struct TakeoutScan {
+    /// Every importable media file, in archive then entry order.
+    pub photos: Vec<TakeoutPhoto>,
+    /// Album names in the order first seen, so the importer creates them in a
+    /// stable order.
+    pub albums: Vec<String>,
+    /// Media files skipped because they sit in the trash bucket.
+    pub skipped_trashed: usize,
+    /// Entries that were neither media nor a sidecar (`archive_browser.html`,
+    /// activity `.csv`s, `.mp` motion-photo parts).
+    pub skipped_other: usize,
+}
+
+impl TakeoutScan {
+    /// Total bytes of media to be read, before duplicate detection.
+    pub fn total_bytes(&self) -> u64 {
+        self.photos.iter().map(|p| p.size).sum()
+    }
+}
+
+/// Google's per-photo sidecar. Only the fields the import uses are read; the
+/// file also carries geo data, people tags and view counts.
+#[derive(Debug, Default, Deserialize)]
+struct PhotoSidecar {
+    #[serde(default)]
+    title: Option<String>,
+    #[serde(rename = "photoTakenTime", default)]
+    photo_taken_time: Option<SidecarTime>,
+    #[serde(rename = "creationTime", default)]
+    creation_time: Option<SidecarTime>,
+    #[serde(default)]
+    favorited: bool,
+}
+
+/// A sidecar timestamp: epoch seconds, as a *string*.
+#[derive(Debug, Deserialize)]
+struct SidecarTime {
+    #[serde(default)]
+    timestamp: Option<String>,
+}
+
+impl SidecarTime {
+    fn epoch_seconds(&self) -> Option<i64> {
+        self.timestamp.as_ref()?.parse().ok()
+    }
+}
+
+/// A folder-level sidecar. `title` is the album name as the user typed it,
+/// which is what the folder name is derived (and sometimes truncated) from.
+#[derive(Debug, Deserialize)]
+struct AlbumSidecar {
+    #[serde(default)]
+    title: Option<String>,
+}
+
+/// One entry as the scan sees it, independent of where it came from.
+struct RawEntry {
+    archive: usize,
+    entry: String,
+    /// `<folder>/<file>` with the export root and service folder removed.
+    relative: String,
+    size: u64,
+}
+
+impl RawEntry {
+    /// The folder component of `relative`, or `""` at the service root.
+    fn folder(&self) -> &str {
+        match self.relative.rfind('/') {
+            Some(index) => &self.relative[..index],
+            None => "",
+        }
+    }
+
+    /// The file name component of `relative`.
+    fn file_name(&self) -> &str {
+        match self.relative.rfind('/') {
+            Some(index) => &self.relative[index + 1..],
+            None => &self.relative,
+        }
+    }
+}
+
+/// Scan a set of Takeout zip archives into one plan.
+///
+/// The archives are treated as one export: an album folder split across parts
+/// is one album, and a sidecar in part 3 is matched to its photo in part 1.
+/// Reads only the central directory and the JSON sidecars — no media bytes, so
+/// this stays fast on a 200 GB export.
+pub fn scan_archives(archives: &[PathBuf]) -> CoreResult<TakeoutScan> {
+    let mut entries: Vec<RawEntry> = Vec::new();
+    let mut sidecars: HashMap<String, Vec<u8>> = HashMap::new();
+
+    for (index, path) in archives.iter().enumerate() {
+        let file = std::fs::File::open(path)
+            .map_err(|e| CoreError::invalid(format!("cannot open {}: {e}", path.display())))?;
+        let mut zip = zip::ZipArchive::new(std::io::BufReader::new(file)).map_err(|e| {
+            CoreError::invalid(format!("{} is not a readable zip: {e}", path.display()))
+        })?;
+
+        for position in 0..zip.len() {
+            let mut entry = zip.by_index(position).map_err(|e| {
+                CoreError::invalid(format!("{}: unreadable entry: {e}", path.display()))
+            })?;
+            if entry.is_dir() {
+                continue;
+            }
+            // `enclosed_name` refuses paths that escape the archive root, which
+            // is exactly the check we want before using one as a key.
+            let Some(name) = entry.enclosed_name() else {
+                continue;
+            };
+            let name = name.to_string_lossy().replace('\\', "/");
+            let Some(relative) = strip_export_prefix(&name) else {
+                continue;
+            };
+            let size = entry.size();
+
+            // Sidecars are read now, while the entry is open: they are a few
+            // hundred bytes each and reopening the archive per photo later would
+            // be a second full pass.
+            if relative.to_ascii_lowercase().ends_with(".json") {
+                let mut body = Vec::with_capacity(size.min(64 * 1024) as usize);
+                if entry.read_to_end(&mut body).is_ok() {
+                    sidecars.insert(relative.to_string(), body);
+                }
+                continue;
+            }
+
+            entries.push(RawEntry {
+                archive: index,
+                entry: name.clone(),
+                relative: relative.to_string(),
+                size,
+            });
+        }
+    }
+
+    Ok(assemble(entries, &sidecars))
+}
+
+/// Build the scan from raw entries plus the sidecar bodies keyed by their path
+/// inside the export. Split out from [`scan_archives`] so the matching rules can
+/// be tested without building zip fixtures.
+fn assemble(entries: Vec<RawEntry>, sidecars: &HashMap<String, Vec<u8>>) -> TakeoutScan {
+    // Album titles per folder, from the folder-level sidecars.
+    let mut album_titles: HashMap<String, String> = HashMap::new();
+    for (path, body) in sidecars {
+        let (folder, file) = split_folder(path);
+        if !ALBUM_METADATA_NAMES.contains(&file.to_ascii_lowercase().as_str()) {
+            continue;
+        }
+        if let Ok(album) = serde_json::from_slice::<AlbumSidecar>(body)
+            && let Some(title) = album.title.filter(|t| !t.trim().is_empty())
+        {
+            album_titles.insert(folder.to_string(), title);
+        }
+    }
+
+    // Per-photo sidecars, indexed by folder so a truncated name only ever
+    // matches within its own folder.
+    let mut per_folder_sidecars: HashMap<String, BTreeMap<String, &Vec<u8>>> = HashMap::new();
+    for (path, body) in sidecars {
+        let (folder, file) = split_folder(path);
+        if ALBUM_METADATA_NAMES.contains(&file.to_ascii_lowercase().as_str()) {
+            continue;
+        }
+        per_folder_sidecars
+            .entry(folder.to_string())
+            .or_default()
+            .insert(file.to_string(), body);
+    }
+
+    let mut scan = TakeoutScan::default();
+    let mut seen_albums: HashMap<String, ()> = HashMap::new();
+
+    for raw in &entries {
+        let folder = raw.folder().to_string();
+        let file_name = raw.file_name().to_string();
+
+        if is_trash_folder(&folder) {
+            if media_type_of(&file_name).is_some() {
+                scan.skipped_trashed += 1;
+            }
+            continue;
+        }
+        let Some(media_type) = media_type_of(&file_name) else {
+            scan.skipped_other += 1;
+            continue;
+        };
+
+        let sidecar = per_folder_sidecars
+            .get(&folder)
+            .and_then(|in_folder| find_sidecar(&file_name, in_folder))
+            .and_then(|body| serde_json::from_slice::<PhotoSidecar>(body).ok())
+            .unwrap_or_default();
+
+        let bucket = match album_titles.get(&folder) {
+            Some(title) => Bucket::Album(title.clone()),
+            None if is_archive_folder(&folder) => Bucket::Archived,
+            None => Bucket::Timeline,
+        };
+        if let Bucket::Album(title) = &bucket
+            && seen_albums.insert(title.clone(), ()).is_none()
+        {
+            scan.albums.push(title.clone());
+        }
+
+        // The sidecar's `title` is the name Google had before it mangled the
+        // on-disk one (truncation, `(1)` suffixes, character replacement), so it
+        // is the better name to upload under — but only when it still looks like
+        // the same file, i.e. the extension agrees.
+        let name = sidecar
+            .title
+            .as_deref()
+            .map(str::trim)
+            .filter(|title| !title.is_empty() && same_extension(title, &file_name))
+            .unwrap_or(&file_name)
+            .to_string();
+
+        scan.photos.push(TakeoutPhoto {
+            archive: raw.archive,
+            entry: raw.entry.clone(),
+            name,
+            size: raw.size,
+            media_type: media_type.to_string(),
+            capture_time: sidecar
+                .photo_taken_time
+                .as_ref()
+                .and_then(SidecarTime::epoch_seconds)
+                .or_else(|| {
+                    sidecar
+                        .creation_time
+                        .as_ref()
+                        .and_then(SidecarTime::epoch_seconds)
+                }),
+            favorite: sidecar.favorited,
+            bucket,
+        });
+    }
+
+    scan
+}
+
+/// Drop the export root (`Takeout/`) and the localized service folder from a
+/// path inside the archive, leaving `<folder>/<file>` or `<file>`.
+///
+/// `None` for a path with no service folder at all (the export's own
+/// `archive_browser.html`), which carries nothing to import.
+fn strip_export_prefix(path: &str) -> Option<&str> {
+    let mut rest = path;
+    // The root is usually `Takeout/`, but an export unzipped and re-zipped by
+    // the user may not have it — so the root is dropped only when a service
+    // folder follows it, which the component count decides.
+    let components = rest.split('/').count();
+    if components >= 3 {
+        rest = rest.split_once('/')?.1;
+    }
+    // Drop the service folder (`Google Photos`, `Google Fotos`, …).
+    let (_service, tail) = rest.split_once('/')?;
+    Some(tail)
+}
+
+/// Split `<folder>/<file>` into its parts; the folder is `""` at the root.
+fn split_folder(path: &str) -> (&str, &str) {
+    match path.rfind('/') {
+        Some(index) => (&path[..index], &path[index + 1..]),
+        None => ("", path),
+    }
+}
+
+fn is_trash_folder(folder: &str) -> bool {
+    let name = folder.rsplit('/').next().unwrap_or(folder).to_lowercase();
+    TRASH_FOLDERS.contains(&name.as_str())
+}
+
+/// Google's archive bucket, which is not an album but is not the plain timeline
+/// either. Only the English name is matched; a missed locale simply imports as
+/// [`Bucket::Timeline`], which is the same upload either way.
+fn is_archive_folder(folder: &str) -> bool {
+    let name = folder.rsplit('/').next().unwrap_or(folder).to_lowercase();
+    name == "archive"
+}
+
+/// Whether two file names end in the same extension, case-insensitively.
+fn same_extension(a: &str, b: &str) -> bool {
+    let ext = |name: &str| {
+        Path::new(name)
+            .extension()
+            .and_then(|e| e.to_str())
+            .map(str::to_ascii_lowercase)
+    };
+    ext(a) == ext(b)
+}
+
+/// Strip a sidecar's `.json` and any `.supplemental-metadata` suffix, including
+/// the *truncated* forms Google produces.
+///
+/// Google caps the sidecar's file name at 51 characters, so a long photo name
+/// leaves only a prefix of the suffix behind — `IMG_1234.jpg.supplemental-me`,
+/// `…-metad`, or nothing at all. Any non-empty prefix of the suffix is stripped;
+/// a bare `.json` sidecar loses only that.
+fn strip_sidecar_suffix(sidecar: &str) -> String {
+    let stem = sidecar
+        .strip_suffix(".json")
+        .or_else(|| sidecar.strip_suffix(".JSON"))
+        .unwrap_or(sidecar);
+    // Longest match first so `.supplemental-metadata` wins over `.s`.
+    for length in (2..=SUPPLEMENTAL.len()).rev() {
+        let candidate = &SUPPLEMENTAL[..length];
+        if let Some(head) = stem.strip_suffix(candidate) {
+            return head.to_string();
+        }
+    }
+    stem.to_string()
+}
+
+/// Move a trailing `(N)` from after the extension to before it: Google writes
+/// the sidecar of `IMG_1234(1).jpg` as `IMG_1234.jpg(1).json`.
+fn unswap_duplicate_marker(stem: &str) -> Option<String> {
+    let marker_start = stem.rfind('(')?;
+    let marker = &stem[marker_start..];
+    if !marker.ends_with(')')
+        || !marker[1..marker.len() - 1]
+            .chars()
+            .all(|c| c.is_ascii_digit())
+    {
+        return None;
+    }
+    let head = &stem[..marker_start];
+    let dot = head.rfind('.')?;
+    Some(format!("{}{}{}", &head[..dot], marker, &head[dot..]))
+}
+
+/// Find the sidecar belonging to `file_name` among the JSON files of its folder.
+///
+/// Tried in order of confidence: the exact name, the `(N)`-swapped name, then a
+/// prefix match for the case where truncation cut into the photo name itself.
+fn find_sidecar<'a>(
+    file_name: &str,
+    in_folder: &BTreeMap<String, &'a Vec<u8>>,
+) -> Option<&'a Vec<u8>> {
+    let mut prefix_match: Option<&'a Vec<u8>> = None;
+    let mut prefix_len = 0usize;
+
+    for (sidecar_name, body) in in_folder {
+        let stem = strip_sidecar_suffix(sidecar_name);
+        if stem == file_name {
+            return Some(body);
+        }
+        if unswap_duplicate_marker(&stem).as_deref() == Some(file_name) {
+            return Some(body);
+        }
+        // Truncated: the stem is a prefix of the photo's name. Keep the longest
+        // such prefix — a folder holding `IMG_1.jpg` and `IMG_12.jpg` must not
+        // let the shorter stem claim the longer photo.
+        if !stem.is_empty() && file_name.starts_with(&stem) && stem.len() > prefix_len {
+            prefix_len = stem.len();
+            prefix_match = Some(body);
+        }
+    }
+    prefix_match
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn entry(archive: usize, path: &str, size: u64) -> RawEntry {
+        RawEntry {
+            archive,
+            entry: path.to_string(),
+            relative: strip_export_prefix(path).unwrap().to_string(),
+            size,
+        }
+    }
+
+    fn sidecar(map: &mut HashMap<String, Vec<u8>>, path: &str, body: &str) {
+        let relative = strip_export_prefix(path).unwrap().to_string();
+        map.insert(relative, body.as_bytes().to_vec());
+    }
+
+    #[test]
+    fn strips_export_root_and_localized_service_folder() {
+        assert_eq!(
+            strip_export_prefix("Takeout/Google Fotos/Island 2019/IMG_1.jpg"),
+            Some("Island 2019/IMG_1.jpg")
+        );
+        // Already unwrapped by the user: no `Takeout/` root left.
+        assert_eq!(
+            strip_export_prefix("Google Photos/IMG_1.jpg"),
+            Some("IMG_1.jpg")
+        );
+        // Nothing below a service folder is nothing to import.
+        assert_eq!(strip_export_prefix("archive_browser.html"), None);
+    }
+
+    #[test]
+    fn album_folder_becomes_an_album_year_folder_does_not() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Iceland 2019/metadata.json",
+            r#"{"title":"Iceland 2019"}"#,
+        );
+        let scan = assemble(
+            vec![
+                entry(0, "Takeout/Google Photos/Iceland 2019/IMG_1.jpg", 10),
+                entry(0, "Takeout/Google Photos/Photos from 2019/IMG_2.jpg", 20),
+            ],
+            &sidecars,
+        );
+
+        assert_eq!(scan.albums, vec!["Iceland 2019"]);
+        assert_eq!(scan.photos[0].bucket, Bucket::Album("Iceland 2019".into()));
+        assert_eq!(scan.photos[1].bucket, Bucket::Timeline);
+        assert_eq!(scan.total_bytes(), 30);
+    }
+
+    #[test]
+    fn trashed_photos_are_skipped_and_counted() {
+        let scan = assemble(
+            vec![
+                entry(0, "Takeout/Google Photos/Papierkorb/IMG_1.jpg", 10),
+                entry(0, "Takeout/Google Photos/Bin/IMG_2.jpg", 10),
+                entry(0, "Takeout/Google Photos/Photos from 2019/IMG_3.jpg", 10),
+            ],
+            &HashMap::new(),
+        );
+
+        assert_eq!(scan.skipped_trashed, 2);
+        assert_eq!(scan.photos.len(), 1);
+        assert_eq!(scan.photos[0].name, "IMG_3.jpg");
+    }
+
+    #[test]
+    fn non_media_entries_are_ignored() {
+        let scan = assemble(
+            vec![
+                entry(0, "Takeout/Google Photos/Photos from 2019/IMG_1.jpg", 10),
+                entry(0, "Takeout/Google Photos/Photos from 2019/notes.txt", 10),
+            ],
+            &HashMap::new(),
+        );
+
+        assert_eq!(scan.photos.len(), 1);
+        assert_eq!(scan.skipped_other, 1);
+    }
+
+    #[test]
+    fn sidecar_supplies_capture_time_and_favourite() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/IMG_1.jpg.supplemental-metadata.json",
+            r#"{"title":"IMG_1.jpg","photoTakenTime":{"timestamp":"1560000000"},"favorited":true}"#,
+        );
+        let scan = assemble(
+            vec![entry(
+                0,
+                "Takeout/Google Photos/Photos from 2019/IMG_1.jpg",
+                10,
+            )],
+            &sidecars,
+        );
+
+        assert_eq!(scan.photos[0].capture_time, Some(1_560_000_000));
+        assert!(scan.photos[0].favorite);
+    }
+
+    #[test]
+    fn creation_time_is_the_fallback_capture_time() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/IMG_1.jpg.json",
+            r#"{"creationTime":{"timestamp":"1500000000"}}"#,
+        );
+        let scan = assemble(
+            vec![entry(
+                0,
+                "Takeout/Google Photos/Photos from 2019/IMG_1.jpg",
+                10,
+            )],
+            &sidecars,
+        );
+
+        assert_eq!(scan.photos[0].capture_time, Some(1_500_000_000));
+    }
+
+    #[test]
+    fn truncated_supplemental_suffixes_still_match() {
+        // Google caps the sidecar name at 51 chars, cutting into the suffix.
+        assert_eq!(
+            strip_sidecar_suffix("IMG_1.jpg.supplemental-me.json"),
+            "IMG_1.jpg"
+        );
+        assert_eq!(
+            strip_sidecar_suffix("IMG_1.jpg.supplemental-metadata.json"),
+            "IMG_1.jpg"
+        );
+        assert_eq!(strip_sidecar_suffix("IMG_1.jpg.json"), "IMG_1.jpg");
+    }
+
+    #[test]
+    fn duplicate_marker_after_the_extension_is_moved_back() {
+        assert_eq!(
+            unswap_duplicate_marker("IMG_1.jpg(1)").as_deref(),
+            Some("IMG_1(1).jpg")
+        );
+        assert_eq!(unswap_duplicate_marker("IMG_1.jpg"), None);
+
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/IMG_1.jpg(1).json",
+            r#"{"photoTakenTime":{"timestamp":"1600000000"}}"#,
+        );
+        let scan = assemble(
+            vec![entry(
+                0,
+                "Takeout/Google Photos/Photos from 2019/IMG_1(1).jpg",
+                10,
+            )],
+            &sidecars,
+        );
+
+        assert_eq!(scan.photos[0].capture_time, Some(1_600_000_000));
+    }
+
+    #[test]
+    fn longest_prefix_wins_when_the_photo_name_itself_was_truncated() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/IMG_1.json",
+            r#"{"photoTakenTime":{"timestamp":"1"}}"#,
+        );
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/IMG_12.json",
+            r#"{"photoTakenTime":{"timestamp":"2"}}"#,
+        );
+        let scan = assemble(
+            vec![entry(
+                0,
+                "Takeout/Google Photos/Photos from 2019/IMG_12345.jpg",
+                10,
+            )],
+            &sidecars,
+        );
+
+        assert_eq!(scan.photos[0].capture_time, Some(2));
+    }
+
+    #[test]
+    fn sidecar_title_replaces_a_mangled_on_disk_name() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/a_very_long_name_that_google_.jpg.json",
+            r#"{"title":"a_very_long_name_that_google_truncated.jpg"}"#,
+        );
+        let scan = assemble(
+            vec![entry(
+                0,
+                "Takeout/Google Photos/Photos from 2019/a_very_long_name_that_google_.jpg",
+                10,
+            )],
+            &sidecars,
+        );
+
+        assert_eq!(
+            scan.photos[0].name,
+            "a_very_long_name_that_google_truncated.jpg"
+        );
+    }
+
+    #[test]
+    fn a_title_with_a_different_extension_is_not_trusted() {
+        // Motion photos name their `.MP` part after the `.jpg`; taking the title
+        // verbatim would upload the video under an image name.
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Photos from 2019/IMG_1.mp4.json",
+            r#"{"title":"IMG_1.jpg"}"#,
+        );
+        let scan = assemble(
+            vec![entry(
+                0,
+                "Takeout/Google Photos/Photos from 2019/IMG_1.mp4",
+                10,
+            )],
+            &sidecars,
+        );
+
+        assert_eq!(scan.photos[0].name, "IMG_1.mp4");
+        assert_eq!(scan.photos[0].media_type, "video/mp4");
+    }
+
+    #[test]
+    fn an_album_split_across_archives_stays_one_album() {
+        let mut sidecars = HashMap::new();
+        sidecar(
+            &mut sidecars,
+            "Takeout/Google Photos/Iceland 2019/metadata.json",
+            r#"{"title":"Iceland 2019"}"#,
+        );
+        let scan = assemble(
+            vec![
+                entry(0, "Takeout/Google Photos/Iceland 2019/IMG_1.jpg", 10),
+                entry(1, "Takeout/Google Photos/Iceland 2019/IMG_2.jpg", 10),
+            ],
+            &sidecars,
+        );
+
+        assert_eq!(scan.albums, vec!["Iceland 2019"]);
+        assert_eq!(scan.photos.len(), 2);
+        assert_eq!(scan.photos[1].archive, 1);
+    }
+
+    #[test]
+    fn archive_bucket_imports_to_the_timeline() {
+        let scan = assemble(
+            vec![entry(0, "Takeout/Google Photos/Archive/IMG_1.jpg", 10)],
+            &HashMap::new(),
+        );
+
+        assert_eq!(scan.photos[0].bucket, Bucket::Archived);
+        assert!(scan.albums.is_empty());
+    }
+
+    /// Write a zip holding `files` and return its path. No `tempfile`
+    /// dev-dependency: the daemon crates deliberately carry none, and one
+    /// uniquely named file under the temp dir is all this needs.
+    fn write_zip(tag: &str, files: &[(&str, &[u8])]) -> PathBuf {
+        use std::io::Write;
+        let path = std::env::temp_dir().join(format!(
+            "pdfs-takeout-test-{tag}-{}.zip",
+            std::process::id()
+        ));
+        let file = std::fs::File::create(&path).unwrap();
+        let mut zip = zip::ZipWriter::new(file);
+        let options: zip::write::FileOptions<'_, ()> =
+            zip::write::FileOptions::default().compression_method(zip::CompressionMethod::Stored);
+        for (name, body) in files {
+            zip.start_file(*name, options).unwrap();
+            zip.write_all(body).unwrap();
+        }
+        zip.finish().unwrap();
+        path
+    }
+
+    #[test]
+    fn scans_a_two_part_export_where_the_sidecar_is_in_the_other_part() {
+        // The case that makes the whole set one scan: part 1 has the photo,
+        // part 2 has its metadata and the album title.
+        let first = write_zip(
+            "part1",
+            &[(
+                "Takeout/Google Photos/Iceland 2019/IMG_1.jpg",
+                b"the photo bytes",
+            )],
+        );
+        let second = write_zip(
+            "part2",
+            &[
+                (
+                    "Takeout/Google Photos/Iceland 2019/metadata.json",
+                    br#"{"title":"Iceland 2019"}"#.as_slice(),
+                ),
+                (
+                    "Takeout/Google Photos/Iceland 2019/IMG_1.jpg.supplemental-metadata.json",
+                    br#"{"title":"IMG_1.jpg","photoTakenTime":{"timestamp":"1560000000"}}"#
+                        .as_slice(),
+                ),
+                (
+                    "Takeout/Google Photos/Trash/IMG_9.jpg",
+                    b"deleted".as_slice(),
+                ),
+            ],
+        );
+
+        let scan = scan_archives(&[first.clone(), second.clone()]).unwrap();
+        let _ = std::fs::remove_file(&first);
+        let _ = std::fs::remove_file(&second);
+
+        assert_eq!(scan.photos.len(), 1);
+        assert_eq!(scan.photos[0].name, "IMG_1.jpg");
+        assert_eq!(scan.photos[0].archive, 0, "the photo is in part 1");
+        assert_eq!(scan.photos[0].size, "the photo bytes".len() as u64);
+        assert_eq!(scan.photos[0].capture_time, Some(1_560_000_000));
+        assert_eq!(scan.photos[0].bucket, Bucket::Album("Iceland 2019".into()));
+        assert_eq!(scan.albums, vec!["Iceland 2019"]);
+        assert_eq!(scan.skipped_trashed, 1);
+    }
+
+    #[test]
+    fn a_file_that_is_not_a_zip_is_a_readable_error() {
+        let path =
+            std::env::temp_dir().join(format!("pdfs-takeout-not-a-zip-{}", std::process::id()));
+        std::fs::write(&path, b"not a zip at all").unwrap();
+        let error = scan_archives(std::slice::from_ref(&path)).unwrap_err();
+        let _ = std::fs::remove_file(&path);
+        assert!(
+            error.message.contains("not a readable zip"),
+            "unexpected message: {}",
+            error.message
+        );
+    }
+}

crates/pdfs-fuse/Cargo.toml

@@ -9,6 +9,8 @@ description = "FUSE on-demand filesystem for Proton Drive"
 
 [dependencies]
 pdfs-core.workspace = true
+zip.workspace = true
+sha1.workspace = true
 proton-drive-rs.workspace = true
 futures.workspace = true
 tokio.workspace = true

crates/pdfs-fuse/src/background.rs

@@ -1,6 +1,7 @@
 //! Remote-event invalidation and local-index background workers.
 
 use super::*;
+use crate::shutdown::Shutdown;
 
 /// 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
@@ -8,35 +9,20 @@ use super::*;
 ///
 /// Returns whether this mount actually held the node, so the caller can evict
 /// its content blob once if *any* mount did.
-fn forget_and_notify(st: &mut State, notifier: Option<&Notifier>, uid: &NodeUid) -> bool {
+fn forget_and_notify(st: &mut State, notify: &mut NotifyBatch, uid: &NodeUid) -> bool {
     // Capture the inode before `forget` clears the uid mapping.
     let child = st.by_uid.get(uid).copied();
     let Some((parent, name)) = st.forget(uid) else {
         return false;
     };
-    if let Some(notifier) = notifier {
-        match child {
-            Some(child) => {
-                let _ = notifier.delete(INodeNo(parent), INodeNo(child), OsStr::new(&name));
-            }
-            None => {
-                let _ = notifier.inval_entry(INodeNo(parent), OsStr::new(&name));
-            }
-        }
+    match child {
+        Some(child) => notify.delete(parent, child, name),
+        None => notify.inval_entry(parent, name),
     }
     true
 }
 
-fn invalidate_access_changes(notifier: Option<&Notifier>, changed: &[u64]) {
-    let Some(notifier) = notifier else {
-        return;
-    };
-    for &ino in changed {
-        let _ = notifier.inval_inode(INodeNo(ino), 0, 0);
-    }
-}
-
-fn hide_foreign_deleted_and_notify(st: &mut State, notifier: Option<&Notifier>, uid: &NodeUid) {
+fn hide_foreign_deleted_and_notify(st: &mut State, notify: &mut NotifyBatch, uid: &NodeUid) {
     let child = st.by_uid.get(uid).copied();
     let dentry = child.and_then(|ino| {
         st.entries
@@ -45,9 +31,9 @@ fn hide_foreign_deleted_and_notify(st: &mut State, notifier: Option<&Notifier>,
     });
     let changed = st.downgrade_shared_subtree(uid);
     st.hide_foreign_subtree(uid);
-    invalidate_access_changes(notifier, &changed);
-    if let (Some(notifier), Some((parent, name)), Some(child)) = (notifier, dentry, child) {
-        let _ = notifier.delete(INodeNo(parent), INodeNo(child), OsStr::new(&name));
+    notify.extend_inodes(&changed);
+    if let (Some((parent, name)), Some(child)) = (dentry, child) {
+        notify.delete(parent, child, name);
     }
 }
 
@@ -132,18 +118,18 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
         && foreign_delete
     {
         apply_foreign_delete(&core.db, node_uid, |uid| {
-            core.for_each_mount(|st, notifier| {
-                hide_foreign_deleted_and_notify(st, notifier, uid);
+            core.for_each_mount(|st, notify| {
+                hide_foreign_deleted_and_notify(st, notify, uid);
             });
         })
     } else {
         apply_access_downgrade(&core.db, event, |root| {
-            core.for_each_mount(|st, notifier| {
+            core.for_each_mount(|st, notify| {
                 let changed = match root {
                     Some(uid) => st.downgrade_shared_subtree(uid),
                     None => st.downgrade_known_shared_access(),
                 };
-                invalidate_access_changes(notifier, &changed);
+                notify.extend_inodes(&changed);
             });
         })
     };
@@ -173,19 +159,17 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
                 debug!(uid = %node_uid, "ignoring remote event for a node with a queued write");
             }
             let mut had_node = false;
-            core.for_each_mount(|st, notifier| {
+            core.for_each_mount(|st, notify| {
                 if *is_trashed {
                     // Trashing makes a node vanish from its parent listing.
-                    had_node |= forget_and_notify(st, notifier, node_uid);
+                    had_node |= forget_and_notify(st, notify, node_uid);
                 } else if !ours && let Some(&ino) = st.by_uid.get(node_uid) {
                     // Known node changed: drop its cached attrs/data (and
                     // listing if it is a directory) so the next access
                     // re-fetches. Its content blob may now be stale too.
                     had_node = true;
                     st.invalidate_listing(ino);
-                    if let Some(notifier) = notifier {
-                        let _ = notifier.inval_inode(INodeNo(ino), 0, 0);
-                    }
+                    notify.inval_inode(ino);
                 }
             });
             // Once, not once per mount: the content cache is per-daemon.
@@ -209,8 +193,8 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
         DriveEvent::NodeDeleted { node_uid, .. } => {
             core.cache.evict(node_uid);
             if !foreign_delete {
-                core.for_each_mount(|st, notifier| {
-                    forget_and_notify(st, notifier, node_uid);
+                core.for_each_mount(|st, notify| {
+                    forget_and_notify(st, notify, node_uid);
                 });
             }
         }
@@ -223,13 +207,11 @@ fn apply_event(core: &Core, event: &DriveEvent, dirty: &mut DirtyParents) -> pdf
         | DriveEvent::SharedWithMeUpdated { .. } => {
             warn!("event access continuity lost; downgrading shared trees and resyncing lazily");
             apply_result = apply_result.and(core.db.clear_state(SHARED_WITH_ME_SYNCED_MS));
-            core.for_each_mount(|st, notifier| {
+            core.for_each_mount(|st, notify| {
                 let dirs: Vec<u64> = st.children.keys().copied().collect();
                 for &ino in &dirs {
                     st.invalidate_listing(ino);
-                    if let Some(notifier) = notifier {
-                        let _ = notifier.inval_inode(INodeNo(ino), 0, 0);
-                    }
+                    notify.inval_inode(ino);
                 }
             });
         }
@@ -303,18 +285,16 @@ fn flush_dirty_parents(core: &Core, dirty: &DirtyParents) {
     if dirty.foreign.is_empty() && dirty.ours.is_empty() {
         return;
     }
-    core.for_each_mount(|st, notifier| {
-        let drop_listing = |st: &mut State, parent_uid: &NodeUid| {
-            let Some(&parent) = st.by_uid.get(parent_uid) else {
-                return;
-            };
-            st.invalidate_listing(parent);
-            if let Some(notifier) = notifier {
-                let _ = notifier.inval_inode(INodeNo(parent), 0, 0);
-            }
+    fn drop_listing(st: &mut State, notify: &mut NotifyBatch, parent_uid: &NodeUid) {
+        let Some(&parent) = st.by_uid.get(parent_uid) else {
+            return;
         };
+        st.invalidate_listing(parent);
+        notify.inval_inode(parent);
+    }
+    core.for_each_mount(|st, notify| {
         for parent_uid in &dirty.foreign {
-            drop_listing(st, parent_uid);
+            drop_listing(st, notify, parent_uid);
         }
         for (parent_uid, children) in &dirty.ours {
             if dirty.foreign.contains(parent_uid) {
@@ -328,7 +308,7 @@ fn flush_dirty_parents(core: &Core, dirty: &DirtyParents) {
             {
                 continue;
             }
-            drop_listing(st, parent_uid);
+            drop_listing(st, notify, parent_uid);
         }
     });
 }
@@ -458,6 +438,7 @@ pub(super) fn run_local_index(
     indexing: Arc<AtomicBool>,
     transfers: Arc<TransferRegistry>,
     mountpoint: PathBuf,
+    shutdown: Arc<Shutdown>,
 ) {
     loop {
         let age = db.local_indexed_at().ok().flatten();
@@ -466,7 +447,11 @@ pub(super) fn run_local_index(
         if stale {
             scan_local_once(&db, &indexing, &transfers, &mountpoint);
         }
-        std::thread::sleep(LOCAL_INDEX_CHECK);
+        // Interruptible, so teardown joins this thread instead of leaving it to
+        // keep rewriting the index for a mount that is gone (bugs.md B44).
+        if !shutdown.sleep(LOCAL_INDEX_CHECK) {
+            return;
+        }
     }
 }
 

crates/pdfs-fuse/src/control.rs

@@ -29,7 +29,23 @@ use super::{Core, count_noun, human_bytes, human_duration, parse_uid};
 
 const MAX_CONTROL_REQUEST_BYTES: u64 = 1024 * 1024;
 const CONTROL_READ_TIMEOUT: Duration = Duration::from_secs(10);
+/// A client that connects, sends a request and then never reads its reply used
+/// to park a handler thread forever in `write_all`; 64 of those exhaust
+/// [`MAX_CONTROL_HANDLERS`] permanently. Generous enough for the largest
+/// responses (photo bytes) over a local socket, finite so a wedged peer can't
+/// hold a permit.
+const CONTROL_WRITE_TIMEOUT: Duration = Duration::from_secs(30);
 const MAX_CONTROL_HANDLERS: usize = 64;
+/// Ceiling on any client-supplied row `limit`. Every in-tree caller asks for far
+/// less (200 for activity, 60 for a photo page), but the value goes straight
+/// into `SQL LIMIT ?` under the daemon's single connection — an unclamped one
+/// materialises the whole account, and then serialises it into one JSON line.
+const MAX_ROW_LIMIT: usize = 1000;
+
+/// Clamp a client-supplied row limit to [`MAX_ROW_LIMIT`].
+fn clamp_limit(limit: usize) -> usize {
+    limit.min(MAX_ROW_LIMIT)
+}
 static ACTIVE_CONTROL_HANDLERS: AtomicUsize = AtomicUsize::new(0);
 
 struct ControlHandlerPermit;
@@ -88,6 +104,31 @@ fn read_request_line(reader: &mut impl BufRead) -> std::io::Result<Option<String
         .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))
 }
 
+/// 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
+/// mutating request still uses. 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
+/// serving a stale listing had no manual escape hatch (`docs/BUGS.md` B86).
+///
+/// A relative path keeps the old meaning, relative to the primary mount, since
+/// there is nothing in it to choose a mount by.
+fn route_to_mount(core: &Core, mountpoint: &Path, path: &str) -> CoreResult<(Core, PathBuf)> {
+    let p = Path::new(path);
+    if !p.is_absolute() {
+        return Ok((core.clone(), p.to_path_buf()));
+    }
+    if let Some(routed) = core.rooted_at(p) {
+        return Ok(routed);
+    }
+    // Fall back to the primary reading so the error text stays the familiar one
+    // when the path is simply outside everything this daemon has mounted.
+    rel_to_mount(mountpoint, path).map(|rel| (core.clone(), rel))
+}
+
 /// 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.
@@ -109,6 +150,10 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
         warn!(error = %e, "control: could not set request timeout");
         return;
     }
+    if let Err(e) = stream.set_write_timeout(Some(CONTROL_WRITE_TIMEOUT)) {
+        warn!(error = %e, "control: could not set response timeout");
+        return;
+    }
     let mut reader = BufReader::new(match stream.try_clone() {
         Ok(s) => s,
         Err(e) => {
@@ -128,7 +173,13 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
         Ok(CtlRequest::Status) => {
             let pins = core.cache.list_pins();
             let queued = core.db.pending_op_counts().unwrap_or_default();
+            let staging = core.cache.staging_usage();
             CtlResponse::Status {
+                parked_uploads: queued.parked.max(0) as u64,
+                failing_ops: queued.failing.max(0) as u64,
+                failing_error: queued.last_error.clone(),
+                staged_bytes: staging.bytes,
+                staged_oldest_secs: staging.oldest_secs,
                 username: username.to_string(),
                 mountpoint: mountpoint.display().to_string(),
                 pinned: pins.len(),
@@ -167,8 +218,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
         Ok(CtlRequest::ListPins) => CtlResponse::Pins {
             pins: core.cache.list_pins(),
         },
-        Ok(CtlRequest::ListDir { path }) => match rel_to_mount(mountpoint, &path) {
-            Ok(rel) => match core.list_dir(&rel) {
+        Ok(CtlRequest::ListDir { path }) => match route_to_mount(core, mountpoint, &path) {
+            Ok((core, rel)) => match core.list_dir(&rel) {
                 Ok(entries) => CtlResponse::Entries { entries },
                 Err(e) => CtlResponse::error(e),
             },
@@ -176,9 +227,8 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
         },
         Ok(CtlRequest::Refresh { scope }) => {
             let result = match &scope {
-                RefreshScope::Dir { path } => {
-                    rel_to_mount(mountpoint, path).and_then(|rel| core.refresh_dir(&rel))
-                }
+                RefreshScope::Dir { path } => route_to_mount(core, mountpoint, path)
+                    .and_then(|(core, rel)| core.refresh_dir(&rel)),
                 RefreshScope::Trash => {
                     core.invalidate_trash();
                     Ok(())
@@ -204,7 +254,7 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             kind,
             range,
             favorites,
-        }) => match core.photos_timeline(offset, limit, kind, range, favorites) {
+        }) => match core.photos_timeline(offset, clamp_limit(limit), kind, range, favorites) {
             Ok(Some(items)) => CtlResponse::Photos {
                 available: true,
                 items,
@@ -245,7 +295,7 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             // An album page is a timeline page as far as the front-end is
             // concerned, so it comes back in the same reply — with `counts`
             // unset, which describe the whole timeline rather than this album.
-            Some(album) => match core.album_photos(&album, offset, limit) {
+            Some(album) => match core.album_photos(&album, offset, clamp_limit(limit)) {
                 Ok(items) => CtlResponse::Photos {
                     available: true,
                     items,
@@ -279,6 +329,51 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             },
             None => CtlResponse::error(CoreError::invalid(format!("bad uid: {uid}"))),
         },
+        // The scan alone walks every archive's central directory, so even the
+        // dry run goes to a background thread and is read back through
+        // `ImportStatus` rather than answered inline.
+        Ok(CtlRequest::ImportTakeout { archives, dry_run }) => {
+            if archives.is_empty() {
+                CtlResponse::error(CoreError::invalid("no Takeout archives given"))
+            } else {
+                let paths: Vec<PathBuf> = archives.into_iter().map(PathBuf::from).collect();
+                let missing: Vec<String> = paths
+                    .iter()
+                    .filter(|path| !path.is_file())
+                    .map(|path| path.display().to_string())
+                    .collect();
+                if !missing.is_empty() {
+                    CtlResponse::error(CoreError::not_found(format!(
+                        "cannot read: {}",
+                        missing.join(", ")
+                    )))
+                } else {
+                    let count = paths.len();
+                    match core.spawn_takeout_import(paths, dry_run) {
+                        Ok(()) => CtlResponse::Ok {
+                            message: format!(
+                                "{} {count} archive(s)",
+                                if dry_run { "scanning" } else { "importing" }
+                            ),
+                        },
+                        Err(e) => CtlResponse::error(e),
+                    }
+                }
+            }
+        }
+        Ok(CtlRequest::ImportStatus) => {
+            let (running, summary) = crate::takeout::import_status();
+            CtlResponse::ImportStatus { running, summary }
+        }
+        Ok(CtlRequest::CancelImport) => {
+            if crate::takeout::cancel_import() {
+                CtlResponse::Ok {
+                    message: "stopping the import".to_string(),
+                }
+            } else {
+                CtlResponse::error(CoreError::invalid("no import is running"))
+            }
+        }
         Ok(CtlRequest::UploadPhoto {
             name,
             media_type,
@@ -346,22 +441,24 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
                 Err(e) => CtlResponse::error(e),
             }
         }
-        Ok(CtlRequest::Search { query, limit }) => match core.search(&query, limit) {
+        Ok(CtlRequest::Search { query, limit }) => match core.search(&query, clamp_limit(limit)) {
             Ok(hits) => CtlResponse::SearchResults { hits },
             Err(e) => CtlResponse::error(e),
         },
-        Ok(CtlRequest::SearchLocal { query, limit }) => match core.search_local(&query, limit) {
-            Ok(hits) => CtlResponse::LocalResults {
-                hits,
-                indexing: core.indexing.load(Ordering::Relaxed),
-            },
-            Err(e) => CtlResponse::error(e),
-        },
+        Ok(CtlRequest::SearchLocal { query, limit }) => {
+            match core.search_local(&query, clamp_limit(limit)) {
+                Ok(hits) => CtlResponse::LocalResults {
+                    hits,
+                    indexing: core.indexing.load(Ordering::Relaxed),
+                },
+                Err(e) => CtlResponse::error(e),
+            }
+        }
         Ok(CtlRequest::SearchV2 {
             query,
             limit,
             filters,
-        }) => match core.search_v2(&query, limit, &filters) {
+        }) => match core.search_v2(&query, clamp_limit(limit), &filters) {
             Ok((drive_hits, local_hits)) => CtlResponse::SearchResultsV2 {
                 drive_hits,
                 local_hits,
@@ -540,19 +637,20 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
         }
         Ok(CtlRequest::CacheInspect { deep }) => match core.db.stats() {
             Ok(stats) => {
-                // The deep check reads every page, so it runs only on request;
-                // `integrity_checked` tells the caller which answer it is
-                // holding, since "no problems found" and "never looked" are
-                // both an empty list.
-                let (integrity_problems, integrity_checked) = if deep {
-                    match core.db.integrity_check() {
-                        Ok(problems) => (problems, true),
-                        Err(e) => (vec![format!("integrity check failed: {e:?}")], true),
-                    }
+                // The deep check reads every page — tens of seconds on a real
+                // database, all of it holding the connection every FUSE handler
+                // needs — so it runs on a thread and this request returns
+                // whatever the last completed check found. `integrity_checked`
+                // tells the caller which answer it is holding, since "no
+                // problems found" and "never looked" are both an empty list;
+                // `integrity_running` says a fresh answer is on its way.
+                let (integrity_problems, integrity_checked, integrity_running) = if deep {
+                    core.start_or_read_integrity_check()
                 } else {
-                    (Vec::new(), false)
+                    (Vec::new(), false, false)
                 };
                 CtlResponse::CacheReport {
+                    integrity_running,
                     schema_version: stats.schema_version,
                     db_bytes: stats.total_bytes(),
                     db_reclaimable_bytes: stats.reclaimable_bytes(),
@@ -565,17 +663,16 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             }
             Err(e) => CtlResponse::error(CoreError::internal(format!("read db stats: {e:?}"))),
         },
-        Ok(CtlRequest::CacheVacuum) => match core.db.vacuum() {
-            Ok(outcome) => CtlResponse::Ok {
-                message: format!(
-                    "vacuumed: {:.1} MiB freed ({:.1} MiB → {:.1} MiB), {} WAL frame(s) checkpointed",
-                    outcome.freed_bytes() as f64 / 1_048_576.0,
-                    outcome.before_bytes as f64 / 1_048_576.0,
-                    outcome.after_bytes as f64 / 1_048_576.0,
-                    outcome.wal_frames_checkpointed,
-                ),
+        // Ack and vacuum on a thread. `VACUUM` rewrites the whole database
+        // under the connection mutex — minutes on a large one — and the
+        // request's own socket timeout is 10 s, so running it inline both froze
+        // the mount and lost its own answer. Progress shows up as a job in
+        // `GetQueueStatus`; the outcome goes to the log.
+        Ok(CtlRequest::CacheVacuum) => match core.start_vacuum() {
+            Ok(()) => CtlResponse::Ok {
+                message: "compacting the cache database in the background".into(),
             },
-            Err(e) => CtlResponse::error(CoreError::internal(format!("vacuum: {e:?}"))),
+            Err(e) => CtlResponse::error(e),
         },
         Ok(CtlRequest::GetQueueStatus) => CtlResponse::Transfers {
             items: core.transfers.snapshot(),
@@ -1023,7 +1120,7 @@ fn handle_control_conn(core: &Core, username: &str, mountpoint: &Path, stream: U
             Err(e) => CtlResponse::error(e),
         },
         Ok(CtlRequest::ListActivity { limit }) => CtlResponse::Activity {
-            items: core.list_activity(limit),
+            items: core.list_activity(clamp_limit(limit)),
         },
         // The request did not parse: the caller sent something malformed.
         Err(e) => CtlResponse::error(CoreError::invalid(format!("bad request: {e}"))),
@@ -1056,6 +1153,12 @@ 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).
+        if core.shutdown.is_stopping() {
+            info!("control socket closing");
+            return;
+        }
         match conn {
             Ok(stream) => {
                 let Some(permit) = ControlHandlerPermit::acquire() else {

crates/pdfs-fuse/src/devices.rs

@@ -536,7 +536,14 @@ impl Core {
         // folder the daemon no longer tracks, and nothing would ever unmount it.
         // Tear it down first — including before trashing the remote tree it
         // serves, which would otherwise leave it answering for deleted nodes.
-        if let Some(mount) = self.mounts.lock().remove(&id)
+        // Taken in its own statement so the registry lock is released before the
+        // teardown: an edition-2024 `if let` chain holds the guard for the whole
+        // body, and `teardown` unmounts and joins the session thread — which can
+        // be inside a multi-second transfer. The shutdown path takes the same
+        // lock, so holding it here risks systemd's stop timeout landing mid-
+        // unmount and stranding the endpoint.
+        let taken = self.mounts.lock().remove(&id);
+        if let Some(mount) = taken
             && let Err(error) = commit_after_teardown(mount.teardown(), || ())
         {
             let _ = self.db.sync_folder_set_state(id, "error", now_secs());
@@ -584,19 +591,8 @@ impl Core {
     pub(crate) fn fork_state(&self) -> Core {
         let mut fork = self.clone();
         fork.primary = false;
-        let share_access = self.state.lock().share_access.clone();
-        fork.state = Arc::new(Mutex::new(State {
-            entries: HashMap::new(),
-            by_uid: HashMap::new(),
-            children: HashMap::new(),
-            next_ino: 2,
-            active_writes: HashMap::new(),
-            handles: HashMap::new(),
-            next_fh: 1,
-            access_changes: std::collections::HashSet::new(),
-            share_access,
-            db: self.db.clone(),
-        }));
+        let share_access = self.state().share_access.clone();
+        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`.
@@ -866,8 +862,11 @@ impl Core {
                 Ok(format!("{} is now on-demand", local.display()))
             }
             ApplicableMountMode::Mirror => {
-                // ondemand→mirror: tear down the secondary mount first.
-                if let Some(mount) = self.mounts.lock().remove(&id)
+                // ondemand→mirror: tear down the secondary mount first. Taken
+                // before the teardown so the registry lock is not held across
+                // the unmount and thread join (see `remove_sync_folder`).
+                let taken = self.mounts.lock().remove(&id);
+                if let Some(mount) = taken
                     && let Err(error) = commit_after_teardown(mount.teardown(), || ())
                 {
                     let _ = self.db.sync_folder_set_state(id, "error", now_secs());

crates/pdfs-fuse/src/drain.rs

@@ -20,10 +20,14 @@
 //! are kept as a conflict copy rather than discarded — see
 //! [`Core::revision_conflict`].
 
+use std::collections::HashMap;
 use std::fs::File;
 use std::path::{Path, PathBuf};
-use std::sync::atomic::Ordering;
-use std::time::Duration;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::time::{Duration, Instant};
+
+use parking_lot::Mutex;
 
 use pdfs_core::batch;
 use pdfs_core::cache::{Baseline, StagedWrite};
@@ -36,17 +40,132 @@ use tracing::{debug, error, info, warn};
 use super::state::Intervals;
 use super::transfers::CountingReader;
 use super::{
-    Core, DRAIN_BACKOFF_MAX, DRAIN_BACKOFF_MIN, DRAIN_IDLE_POLL, ROOT_INO, conflict_name,
+    Core, DRAIN_BACKOFF_MAX, DRAIN_BACKOFF_MIN, DRAIN_IDLE_POLL, DRAIN_REVISION_DEBOUNCE,
+    DRAIN_REVISION_DEBOUNCE_MAX, ROOT_INO, UPLOAD_TIME_MEMORY, WriteAuthority, conflict_name,
     is_already_exists, is_gone, is_local_uid_str, media_type_for, node_revision_id, node_size,
     now_millis, now_secs, parse_node_uid,
 };
 
 const DRAIN_ACCESS_RECHECK: Duration = Duration::from_secs(5);
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+/// How long an op may stay access-deferred before the deferral is reported as a
+/// failure instead of retried in silence.
+///
+/// An access deferral costs no attempt and records no error, which is right for
+/// the case it was written for: a share downgraded while the queue was moving,
+/// undone a moment later. It is wrong for anything that does not clear. Until
+/// this window existed such an op was re-deferred every
+/// [`DRAIN_ACCESS_RECHECK`] indefinitely with `attempts` at zero, `last_error`
+/// null and only a `debug!` line to show for it, so `pdfs status` counted it
+/// among ordinary queued uploads and nothing ever said otherwise.
+///
+/// The condition that produced that in practice — a node absent from the local
+/// tree, which [`Db::effective_node_access`] used to report indistinguishably
+/// from a revoked permission — is now answered directly by
+/// [`Core::resolve_unknown_authority`]. This window remains the backstop for
+/// every deferral that does not resolve, including a refetch that keeps not
+/// helping.
+///
+/// Five minutes is far longer than a permission change takes to settle and far
+/// shorter than a user's patience with bytes that are not moving. Past it each
+/// recheck records a failure, so the op enters the ordinary backoff and, at
+/// [`FAILING_ATTEMPTS`], is counted and named by `Response::Status`.
+///
+/// [`Db::effective_node_access`]: pdfs_core::db::Db::effective_node_access
+/// [`FAILING_ATTEMPTS`]: pdfs_core::db::FAILING_ATTEMPTS
+const DRAIN_ACCESS_DEFER_LIMIT: Duration = Duration::from_secs(300);
+
+/// A registered cancellation flag for one in-flight upload, deregistered when
+/// dropped. See [`Core::begin_cancellable_upload`].
+struct UploadCancel {
+    registry: Arc<Mutex<HashMap<NodeUid, Arc<AtomicBool>>>>,
+    uid: NodeUid,
+    flag: Arc<AtomicBool>,
+}
+
+impl UploadCancel {
+    /// Whether this upload was told to stop. Distinguishes an upload we
+    /// abandoned on purpose from one the network broke.
+    fn cancelled(&self) -> bool {
+        self.flag.load(Ordering::Relaxed)
+    }
+
+    fn flag(&self) -> Arc<AtomicBool> {
+        self.flag.clone()
+    }
+}
+
+impl Drop for UploadCancel {
+    fn drop(&mut self) {
+        let mut registry = self.registry.lock();
+        // By identity: a supersede racing this upload's last bytes may already
+        // have registered the next one under the same uid.
+        if registry
+            .get(&self.uid)
+            .is_some_and(|current| Arc::ptr_eq(current, &self.flag))
+        {
+            registry.remove(&self.uid);
+        }
+    }
+}
+
+/// The debounce arithmetic of [`Core::revision_debounce`], without the map:
+/// the last measured upload time for this node, bounded on both sides.
+///
+/// A node nobody has uploaded yet gets the fixed grace period, which is the
+/// same answer the fixed debounce always gave.
+fn adaptive_debounce(measured: Option<Duration>) -> Duration {
+    measured
+        .unwrap_or(DRAIN_REVISION_DEBOUNCE)
+        .clamp(DRAIN_REVISION_DEBOUNCE, DRAIN_REVISION_DEBOUNCE_MAX)
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
 enum DrainDisposition {
     Applied,
     AccessDeferred,
+    /// An authority this op needs is missing from the local tree, so no access
+    /// answer exists for it yet. Carries the uid to ask the remote about.
+    AuthorityUnknown(NodeUid),
+}
+
+/// Why an op went back on the clock without consuming an attempt. Only affects
+/// what the user is told — every variant is deferred and reported identically.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum AccessDeferral {
+    /// An authority the tree knows about refuses the write.
+    NotWritable,
+    /// An authority missing from the tree was just re-read from the remote and
+    /// re-interned; the access check gets another look on the next pass.
+    AuthorityRefetched,
+    /// An authority missing from the tree could not be asked about.
+    RemoteUnreachable,
+}
+
+impl AccessDeferral {
+    fn log_reason(self) -> &'static str {
+        match self {
+            Self::NotWritable => "the node is not writable",
+            Self::AuthorityRefetched => "the node was missing locally and has been re-read",
+            Self::RemoteUnreachable => "the node is missing locally and the remote is unreachable",
+        }
+    }
+
+    /// Phrased to complete "<reason> for 300s." in a recorded `last_error`, so
+    /// the text the user sees names the actual condition rather than the
+    /// permission question it used to be flattened into.
+    fn failure_reason(self) -> &'static str {
+        match self {
+            Self::NotWritable => "the share has not been writable",
+            Self::AuthorityRefetched => {
+                "the node has been missing from the local tree, and re-reading it from the remote \
+                 has not restored it"
+            }
+            Self::RemoteUnreachable => {
+                "the node has been missing from the local tree and the remote has been unreachable"
+            }
+        }
+    }
 }
 
 fn pending_op_authorities(op: &PendingOp) -> Result<Vec<NodeUid>, Box<dyn std::error::Error>> {
@@ -89,7 +208,7 @@ fn pending_op_authorities(op: &PendingOp) -> Result<Vec<NodeUid>, Box<dyn std::e
 
 fn run_authorized_drain(
     op: &PendingOp,
-    mut require: impl FnMut(&NodeUid) -> Result<(), fuser::Errno>,
+    mut authority_of: impl FnMut(&NodeUid) -> WriteAuthority,
     apply: impl FnOnce() -> Result<(), Box<dyn std::error::Error>>,
 ) -> Result<DrainDisposition, Box<dyn std::error::Error>> {
     // This check is the admission/linearization point. A downgrade that lands
@@ -97,15 +216,14 @@ fn run_authorized_drain(
     // attempt. Every later queued operation rechecks. No permission lock is
     // held across remote latency.
     for authority in pending_op_authorities(op)? {
-        match require(&authority) {
-            Ok(()) => {}
-            Err(error) if error.code() == libc::EACCES => {
-                return Ok(DrainDisposition::AccessDeferred);
-            }
-            Err(error) => {
-                return Err(
-                    format!("drain access check failed with errno {}", error.code()).into(),
-                );
+        match authority_of(&authority) {
+            WriteAuthority::Writable => {}
+            WriteAuthority::Denied => return Ok(DrainDisposition::AccessDeferred),
+            // Nothing in the tree can answer for this node. Deferring on it
+            // waits for a permission change that has no reason to come, so the
+            // caller asks the remote instead (B83).
+            WriteAuthority::Unknown => {
+                return Ok(DrainDisposition::AuthorityUnknown(authority));
             }
         }
     }
@@ -127,44 +245,85 @@ impl Core {
     /// that is due — one file wedged against a folder that no longer exists must
     /// not hold up an unrelated upload behind it. The worker only blocks once
     /// nothing is due at all.
-    pub(crate) fn run_pending_drain(&self) {
+    ///
+    /// Several of these run at once ([`DRAIN_WORKERS`]), sharing the queue
+    /// through [`Db::claim_next_due_op`]: the alternative was that a 10 GiB
+    /// upload held every queued rename, trash and small write behind it for as
+    /// long as it took. Ordering only has to hold *per node*, and the claim
+    /// query is what guarantees it — no two workers are ever on one uid.
+    ///
+    /// `primary` marks the one worker that also runs the queue's idle chores.
+    /// They are cheap, but they are not per-op work and doing them in every
+    /// worker would just multiply them.
+    ///
+    /// [`DRAIN_WORKERS`]: super::DRAIN_WORKERS
+    /// [`Db::claim_next_due_op`]: pdfs_core::db::Db::claim_next_due_op
+    pub(crate) fn run_pending_drain(&self, primary: bool) {
         loop {
+            // Between ops, never inside one: an op that has started is either
+            // retired or released, so stopping here cannot leave the queue with
+            // a row claimed by a worker that no longer exists (bugs.md B44).
+            if self.shutdown.is_stopping() {
+                debug!(primary, "drain worker stopping");
+                return;
+            }
             let now = now_millis();
-            // One row, chosen by the database. Reading the whole queue to pick
-            // one op made a long queue quadratic to drain, and held the shared
-            // connection — and so every FUSE metadata call — for the duration.
-            let due = self.db.next_due_op(now).unwrap_or_default();
-
-            let Some(op) = due.filter(|_| self.online.load(Ordering::Relaxed)) else {
-                self.recover_fsynced_writes();
-                // A debounced or backed-off op may be waiting: sleep only
-                // until it becomes due rather than the full idle-poll.
-                self.wait_for_drain_work_or_due();
-                continue;
+            // One row, chosen and *claimed* by the database. Reading the whole
+            // queue to pick one op made a long queue quadratic to drain, and
+            // held the shared connection — and so every FUSE metadata call —
+            // for the duration.
+            let due = match self.db.claim_next_due_op(now) {
+                Ok(due) => due,
+                Err(error) => {
+                    error!(%error, "claiming the next pending operation failed");
+                    self.wait_for_drain_work();
+                    continue;
+                }
+            };
+            let online = self.online.load(Ordering::Relaxed);
+            let op = match due {
+                Some(op) if online => op,
+                idle => {
+                    // Claimed but offline: hand it straight back, or it stays
+                    // invisible to every worker until this one happens to be
+                    // the next to notice the reconnect.
+                    if let Some(op) = idle {
+                        self.release_claim(&op);
+                    }
+                    if primary {
+                        // Nothing to upload is exactly when the connection is
+                        // free, so this is where the read path's buffered LRU
+                        // touches get written (`ContentCache::flush_touches`).
+                        // Cheap and a no-op when empty.
+                        self.cache.flush_touches();
+                        self.recover_fsynced_writes();
+                    }
+                    // A debounced or backed-off op may be waiting: sleep only
+                    // until it becomes due rather than the full idle-poll.
+                    self.wait_for_drain_work_or_due();
+                    continue;
+                }
             };
             let outcome = run_authorized_drain(
                 &op,
-                |uid| self.require_uid_writable(uid),
+                |uid| self.uid_write_authority(uid),
                 || self.drain_op(&op),
             );
             if matches!(outcome, Ok(DrainDisposition::AccessDeferred)) {
-                let next_attempt_at = now_millis() + DRAIN_ACCESS_RECHECK.as_millis() as i64;
-                if let Err(error) = self.db.defer_op_without_attempt(op.id, next_attempt_at) {
-                    error!(
-                        uid = %op.uid,
-                        %error,
-                        "deferring access-blocked pending operation failed"
-                    );
-                    self.wait_for_drain_work();
-                } else {
-                    debug!(
-                        uid = %op.uid,
-                        next_attempt_at,
-                        "pending operation deferred until access is writable"
-                    );
-                }
+                self.defer_for_access(&op, AccessDeferral::NotWritable);
                 continue;
             }
+            if let Ok(DrainDisposition::AuthorityUnknown(ref authority)) = outcome {
+                self.resolve_unknown_authority(&op, authority);
+                continue;
+            }
+            // The access check let this attempt through, so any earlier run of
+            // deferrals is over and must not be counted against the next one.
+            if matches!(outcome, Ok(DrainDisposition::Applied))
+                && let Err(error) = self.db.clear_op_access_deferral(op.id)
+            {
+                debug!(uid = %op.uid, %error, "clearing an access-deferral window failed");
+            }
             if let Err(e) = outcome {
                 let attempts = op.attempts + 1;
                 let err_str = e.to_string();
@@ -184,9 +343,234 @@ impl Core {
                     now_millis() + backoff.as_millis() as i64,
                 ) {
                     error!(uid = %op.uid, error = %e, "recording a drain failure failed");
+                    self.release_claim(&op);
                     self.wait_for_drain_work();
+                    continue;
                 }
             }
+            // Unconditionally, on every path: a handler that retired its own row
+            // leaves nothing to release, and one that returned without retiring
+            // must not leave the row claimed by a worker that has moved on.
+            self.release_claim(&op);
+        }
+    }
+
+    /// Put an op the access check refused back on the clock, and decide whether
+    /// its refusal is still news.
+    ///
+    /// Inside [`DRAIN_ACCESS_DEFER_LIMIT`] a deferral is what it always was: no
+    /// attempt consumed, no error recorded, retried in five seconds. Past it the
+    /// deferral is reported through [`Db::record_op_failure`] like any other
+    /// stuck op, which is what puts it in `attempts`, in `last_error`, and — at
+    /// [`FAILING_ATTEMPTS`] — in the `failing_ops` count and error text that
+    /// `pdfs status` and the GUI show. The row and its staged blob stay exactly
+    /// where they are either way; this changes only whether the user can see
+    /// them.
+    ///
+    /// [`Db::record_op_failure`]: pdfs_core::db::Db::record_op_failure
+    /// [`FAILING_ATTEMPTS`]: pdfs_core::db::FAILING_ATTEMPTS
+    fn defer_for_access(&self, op: &PendingOp, reason: AccessDeferral) {
+        let now = now_millis();
+        let next_attempt_at = now + DRAIN_ACCESS_RECHECK.as_millis() as i64;
+        let since = match self.db.defer_op_for_access(op.id, now, next_attempt_at) {
+            Ok(since) => since,
+            Err(error) => {
+                error!(
+                    uid = %op.uid,
+                    %error,
+                    "deferring access-blocked pending operation failed"
+                );
+                self.release_claim(op);
+                self.wait_for_drain_work();
+                return;
+            }
+        };
+        let blocked = Duration::from_millis(now.saturating_sub(since).max(0) as u64);
+        if since == now {
+            // The first deferral of a run, at `warn!`: a write the mount accepted
+            // is not going anywhere for now, and that is worth a line even when
+            // the next recheck clears it.
+            warn!(
+                uid = %op.uid,
+                kind = %op.kind,
+                reason = reason.log_reason(),
+                "pending operation deferred"
+            );
+        }
+        if blocked >= DRAIN_ACCESS_DEFER_LIMIT {
+            let attempts = op.attempts + 1;
+            let backoff = DRAIN_BACKOFF_MIN
+                .saturating_mul(1u32 << attempts.min(6))
+                .min(DRAIN_BACKOFF_MAX);
+            let error = format!(
+                "{} for {}s. The staged bytes are kept.",
+                reason.failure_reason(),
+                blocked.as_secs()
+            );
+            warn!(uid = %op.uid, attempts, blocked_secs = blocked.as_secs(),
+                  "pending operation has been access-blocked past the limit; reporting it");
+            if let Err(error) =
+                self.db
+                    .record_op_failure(op.id, &error, now_millis() + backoff.as_millis() as i64)
+            {
+                error!(uid = %op.uid, %error, "recording an access-deferral failure failed");
+            }
+        } else {
+            debug!(
+                uid = %op.uid,
+                next_attempt_at,
+                blocked_secs = blocked.as_secs(),
+                reason = reason.log_reason(),
+                "pending operation deferred until access is writable"
+            );
+        }
+        self.release_claim(op);
+    }
+
+    /// Answer an authority the local tree has no row for by asking the remote,
+    /// rather than deferring on a permission question nobody asked (B83).
+    ///
+    /// Three outcomes, and the point of the whole exercise is that they are
+    /// three:
+    ///
+    /// * the node is still there — the tree simply lost it (a pruned subtree, a
+    ///   mount whose registration went away). Re-intern it and the next pass has
+    ///   a real access answer to work with.
+    /// * the node is gone remotely. That is a permanent, *known* condition, so
+    ///   it is recorded as a failure immediately instead of waiting out
+    ///   [`DRAIN_ACCESS_DEFER_LIMIT`] to say so. The row and its staged blob are
+    ///   kept, as on every other failure path — the bytes are still the user's,
+    ///   and `pdfs recover` is how they get them back.
+    /// * we could not ask. Ordinary deferral; the network is the network.
+    fn resolve_unknown_authority(&self, op: &PendingOp, authority: &NodeUid) {
+        match self.fetch_node_remote(authority) {
+            Ok(Some(node)) => {
+                if let Err(error) = self.db.upsert_node(&node) {
+                    error!(uid = %op.uid, %authority, %error,
+                           "re-interning a queued operation's missing authority failed");
+                } else {
+                    info!(uid = %op.uid, %authority,
+                          "re-interned an authority missing from the local tree; retrying");
+                }
+                // Deferred, not applied: the re-read has to go through the same
+                // access check as everything else, on the next pass. The window
+                // keeps running, so a refetch that never actually helps still
+                // gets reported instead of looping in silence.
+                self.defer_for_access(op, AccessDeferral::AuthorityRefetched);
+            }
+            Ok(None) => {
+                let attempts = op.attempts + 1;
+                let backoff = DRAIN_BACKOFF_MIN
+                    .saturating_mul(1u32 << attempts.min(6))
+                    .min(DRAIN_BACKOFF_MAX);
+                let error = format!(
+                    "{authority} no longer exists remotely, so this operation has nothing to \
+                     apply to. The staged bytes are kept."
+                );
+                warn!(uid = %op.uid, %authority, attempts,
+                      "a queued operation's authority is gone remotely; reporting it");
+                if let Err(error) = self.db.record_op_failure(
+                    op.id,
+                    &error,
+                    now_millis() + backoff.as_millis() as i64,
+                ) {
+                    error!(uid = %op.uid, %error, "recording a missing-authority failure failed");
+                }
+                self.release_claim(op);
+            }
+            Err(error) => {
+                debug!(uid = %op.uid, %authority, %error,
+                       "could not ask the remote about a missing authority");
+                self.defer_for_access(op, AccessDeferral::RemoteUnreachable);
+            }
+        }
+    }
+
+    /// Hand a claimed op back to the queue, logging rather than propagating —
+    /// there is no caller left to propagate to, and the drain must not stop.
+    fn release_claim(&self, op: &PendingOp) {
+        if let Err(error) = self.db.release_op_claim(op.id) {
+            error!(uid = %op.uid, %error, "releasing a drain claim failed");
+        }
+    }
+
+    /// How long a freshly queued revision of `uid` should wait before a worker
+    /// may pick it up.
+    ///
+    /// [`DRAIN_REVISION_DEBOUNCE`] exists for a tool that preallocates a file
+    /// and then writes it, where two seconds is the right scale. It is the wrong
+    /// scale for a large file on a slow link: an editor saving a 200 MB project
+    /// every ten seconds queues a write, the drain starts sending it, the next
+    /// save supersedes it mid-flight, and the file never finishes uploading
+    /// while the user keeps working. Waiting roughly as long as the last upload
+    /// of *this* node took moves that supersede into the queue, where replacing
+    /// a row costs nothing.
+    ///
+    /// Never shorter than the fixed debounce and never longer than
+    /// [`DRAIN_REVISION_DEBOUNCE_MAX`]: a node whose upload is genuinely slow
+    /// still has to reach Drive, and a single pathological stall must not park
+    /// it.
+    ///
+    /// [`DRAIN_REVISION_DEBOUNCE`]: super::DRAIN_REVISION_DEBOUNCE
+    /// [`DRAIN_REVISION_DEBOUNCE_MAX`]: super::DRAIN_REVISION_DEBOUNCE_MAX
+    pub(crate) fn revision_debounce(&self, uid: &NodeUid) -> Duration {
+        let measured = self
+            .upload_times
+            .lock()
+            .get(&uid.to_string())
+            .map(|&(ms, _)| Duration::from_millis(ms));
+        adaptive_debounce(measured)
+    }
+
+    /// Remember how long an upload of `uid` took, for the next write's
+    /// debounce.
+    ///
+    /// Only a *completed* upload is a measurement. A cancelled or failed one
+    /// says how long it ran before it stopped, which is not how long the file
+    /// takes to send, and feeding that back would let one network fault widen
+    /// the debounce for good.
+    fn record_upload_time(&self, uid: &NodeUid, took: Duration) {
+        let mut times = self.upload_times.lock();
+        let now = now_millis();
+        if times.len() >= UPLOAD_TIME_MEMORY
+            && !times.contains_key(&uid.to_string())
+            && let Some(oldest) = times
+                .iter()
+                .min_by_key(|(_, (_, at))| *at)
+                .map(|(k, _)| k.clone())
+        {
+            times.remove(&oldest);
+        }
+        times.insert(uid.to_string(), (took.as_millis() as u64, now));
+    }
+
+    /// Register a cancellation flag for an upload of `uid` that is about to
+    /// start, returning a guard that deregisters it.
+    ///
+    /// Deregistration is by identity rather than by key: a supersede that
+    /// arrives just as this upload finishes may already have registered the
+    /// *next* upload's flag under the same uid, and removing that one would
+    /// leave the newer upload uncancellable.
+    fn begin_cancellable_upload(&self, uid: &NodeUid) -> UploadCancel {
+        let flag = Arc::new(AtomicBool::new(false));
+        self.upload_cancel.lock().insert(uid.clone(), flag.clone());
+        UploadCancel {
+            registry: self.upload_cancel.clone(),
+            uid: uid.clone(),
+            flag,
+        }
+    }
+
+    /// Tell an upload of `uid` that is on the wire to stop, if there is one.
+    ///
+    /// Called when a newer revision of the file is queued. The upload does not
+    /// stop instantly — it stops when the SDK next asks its reader for bytes,
+    /// which for a 4 MiB block is soon enough to matter and late enough to be
+    /// safe: the staged blob it is reading stays open until it lets go.
+    pub(crate) fn cancel_upload(&self, uid: &NodeUid) {
+        if let Some(flag) = self.upload_cancel.lock().get(uid) {
+            flag.store(true, Ordering::Relaxed);
+            debug!(%uid, "cancelling a superseded upload");
         }
     }
 
@@ -351,6 +735,9 @@ impl Core {
         }
         self.db.complete_trash_op(op.id, &uid)?;
         self.own_sealed_revs.lock().remove(&uid);
+        if let Err(e) = self.db.clear_own_sealed_rev(&uid.to_string()) {
+            debug!(%uid, error = %e, "clearing the sealed-revision record failed");
+        }
         self.invalidate_trash();
         self.log_activity(ActivityKind::Trash, &name, "trashed", true);
         info!(%uid, name, "pending trash landed");
@@ -625,7 +1012,16 @@ impl Core {
         // instead of forking — so the finished bytes win the name rather than
         // being exiled to a `(sync-conflict)` copy.
         let remote_rev = node_revision_id(&node);
-        let own_rev = self.own_sealed_revs.lock().get(uid).cloned();
+        // In memory first, then the table it is written through to: the map is
+        // this process's cache of it, and after a restart only the table has
+        // the answer (which is the whole reason it is persisted).
+        let own_rev = match self.own_sealed_revs.lock().get(uid).cloned() {
+            Some(rev) => Some(rev),
+            None => self
+                .db
+                .own_sealed_rev(&uid.to_string(), now_millis())
+                .unwrap_or_default(),
+        };
         if is_own_self_supersede(meta.complete, remote_rev.as_deref(), own_rev.as_deref()) {
             debug!(%uid, ?remote_rev,
                    "queued write chains onto our own sealed revision; not a conflict");
@@ -709,8 +1105,9 @@ impl Core {
         self.db.delete_op(op.id)?;
         // Dropping the pending entry hands the node back to the remote's truth:
         // reads stop coming from the staged blob, and the event sync stops
-        // skipping it as "ahead of the server" (offline.md Phase 3a).
-        self.pending.lock().remove(uid);
+        // skipping it as "ahead of the server" (offline.md Phase 3a). Only if it
+        // is still *this* write's entry — see [`Core::release_pending`].
+        self.release_pending(uid, blob);
         self.cache.discard_staged(blob);
         self.cache.evict(uid);
         self.evict_reader(uid);
@@ -748,7 +1145,7 @@ impl Core {
         error!(%uid, name, reason, staged = %blob.display(),
                "cannot place a conflicted write; bytes kept in staging");
         self.db.delete_op(op.id)?;
-        self.pending.lock().remove(uid);
+        self.release_pending(uid, blob);
         self.cache.evict(uid);
         self.evict_reader(uid);
         self.log_activity(
@@ -760,6 +1157,24 @@ impl Core {
         Ok(())
     }
 
+    /// Drop `uid`'s pending entry, but only while it still names `blob`.
+    ///
+    /// A supersede can replace the entry while the op that owned it is in
+    /// flight, so an unconditional `remove` retires a *newer* write's staged
+    /// blob: reads fall back to a stale remote, the next `remote_baseline` forks
+    /// a spurious `(sync-conflict)` copy of bytes that were never in conflict,
+    /// and the incomplete-write interlock — which keys off the pending entry —
+    /// is disarmed, letting a gap-fill read from a revision that no longer
+    /// describes the file.
+    pub(crate) fn release_pending(&self, uid: &NodeUid, blob: &Path) {
+        let mut pending = self.pending.lock();
+        if let Some(current) = pending.get(uid)
+            && current.path == blob
+        {
+            pending.remove(uid);
+        }
+    }
+
     /// Whether a folder a queued op targets has stopped being a place a node can
     /// go. A failure to ask is not an answer: only a definite "trashed" or "not
     /// there" counts, so a network fault leaves the op to retry normally.
@@ -826,7 +1241,7 @@ impl Core {
     /// root yet, which is not where the drain runs; the drain must not panic
     /// over it regardless, since that would stop the queue for good.
     pub(crate) fn root_uid(&self) -> Option<NodeUid> {
-        let st = self.state.lock();
+        let st = self.state();
         st.entries.get(&ROOT_INO).map(|e| e.uid.clone())
     }
 
@@ -872,28 +1287,43 @@ impl Core {
         let guard =
             self.transfers
                 .begin(&name, meta.uid.clone(), TransferDirection::Upload, meta.len);
-        let reader = CountingReader::new(File::open(&blob)?, &guard);
-        self.rt.block_on(self.client.upload_new_revision_from(
+        // Registered before the first byte moves, so a write that lands while
+        // this is on the wire can stop it rather than paying for a revision the
+        // op it queued will immediately replace.
+        let cancel = self.begin_cancellable_upload(&uid);
+        let reader = CountingReader::new(File::open(&blob)?, &guard).with_cancel(cancel.flag());
+        let started = Instant::now();
+        let sent = self.rt.block_on(self.client.upload_new_revision_from(
             &uid,
             reader,
             meta.len as i64,
             Vec::new(),
             None,
-        ))?;
+        ));
+        let took = started.elapsed();
+        if let Err(e) = sent {
+            if cancel.cancelled() {
+                // Not a failure, and not this op's row to retire: the write that
+                // cancelled us deleted it and took ownership of the staged blob
+                // when it superseded this revision. Leaving the blob alone here
+                // is the whole point — it is either already unlinked or it
+                // belongs to the newer op.
+                info!(%uid, "upload abandoned; a newer write superseded it");
+                return Ok(());
+            }
+            return Err(e.into());
+        }
+        drop(cancel);
         drop(guard);
+        // Only a completed upload times how long this file takes to send, which
+        // is what the next write's debounce is scaled from.
+        self.record_upload_time(&uid, took);
 
         // Retire the op before dropping the blob: a crash between the two leaves
         // an orphaned file (harmless), whereas the reverse would leave a queued
         // op pointing at nothing.
         self.db.delete_op(op.id)?;
-        {
-            let mut p = self.pending.lock();
-            if let Some(op_in_mem) = p.get(&uid)
-                && op_in_mem.path == blob
-            {
-                p.remove(&uid);
-            }
-        }
+        self.release_pending(&uid, &blob);
 
         // The staged blob now matches the sealed revision, so a pinned file keeps
         // it as its cached content rather than re-downloading what we just sent.
@@ -969,7 +1399,16 @@ impl Core {
             // change and does not fork (B70 layer B; consulted in
             // `revision_conflict`).
             if let Some(rev) = sealed_rev.clone() {
-                self.own_sealed_revs.lock().insert(uid.clone(), rev);
+                self.own_sealed_revs.lock().insert(uid.clone(), rev.clone());
+                // Write through: losing this at shutdown reopened the fork
+                // window B70 layer B closed, for the first drain after a
+                // restart.
+                if let Err(e) = self
+                    .db
+                    .set_own_sealed_rev(&uid.to_string(), &rev, now_millis())
+                {
+                    warn!(%uid, error = %e, "persisting our sealed revision failed");
+                }
             }
             self.for_each_state(|st| {
                 for aw in st.active_writes.values_mut() {
@@ -1190,12 +1629,10 @@ mod tests {
         let applied = Cell::new(false);
         let disposition = run_authorized_drain(
             &op,
-            |uid| {
-                db.effective_node_access(uid)
-                    .unwrap()
-                    .filter(|access| access.writable())
-                    .map(|_| ())
-                    .ok_or(fuser::Errno::EACCES)
+            |uid| match db.effective_node_access(uid).unwrap() {
+                Some(access) if access.writable() => WriteAuthority::Writable,
+                Some(_) => WriteAuthority::Denied,
+                None => WriteAuthority::Unknown,
             },
             || {
                 applied.set(true);
@@ -1235,7 +1672,7 @@ mod tests {
 
         let disposition = run_authorized_drain(
             &op,
-            |_| Err(fuser::Errno::EACCES),
+            |_| WriteAuthority::Denied,
             || {
                 applied.set(true);
                 Ok(())
@@ -1256,13 +1693,157 @@ mod tests {
         let _ = std::fs::remove_dir_all(dir);
     }
 
+    /// A deferral that never clears has to stop being silent. Found in the field
+    /// as revision ops whose node had left the local tree: `require_uid_access`
+    /// reads an unknown node as `EACCES`, so they were re-deferred every five
+    /// seconds for thirty days with `attempts` at zero, `last_error` null and
+    /// `failing_ops` at zero — 18 GiB of accepted writes that `pdfs status`
+    /// reported as ordinary queued uploads.
+    #[test]
+    fn an_access_deferral_that_outlives_the_limit_is_reported_as_failing() {
+        use std::sync::atomic::{AtomicU64, Ordering};
+
+        static N: AtomicU64 = AtomicU64::new(0);
+        let dir = std::env::temp_dir().join(format!(
+            "pdfs-drain-defer-limit-{}-{}",
+            std::process::id(),
+            N.fetch_add(1, Ordering::Relaxed)
+        ));
+        std::fs::create_dir_all(&dir).unwrap();
+        let db = Db::open(&dir.join("cache.db")).unwrap();
+        db.enqueue_op(&pending(OP_REVISION)).unwrap();
+        let op = db.pending_ops().unwrap().remove(0);
+
+        // Two deferrals a recheck apart: the window opens on the first and the
+        // second is measured against it, not against itself.
+        let now = 1_000_000i64;
+        let since = db.defer_op_for_access(op.id, now, now + 5_000).unwrap();
+        assert_eq!(since, now, "the first deferral opens the window");
+        let later = now + DRAIN_ACCESS_RECHECK.as_millis() as i64;
+        assert_eq!(
+            db.defer_op_for_access(op.id, later, later + 5_000).unwrap(),
+            now,
+            "a later deferral keeps the original stamp"
+        );
+        let queued = db.pending_ops().unwrap();
+        assert_eq!(queued[0].attempts, 0, "deferrals consume no attempt");
+        assert!(queued[0].last_error.is_none());
+
+        // Past the limit the same deferral is reported like any other stuck op.
+        let past = now + DRAIN_ACCESS_DEFER_LIMIT.as_millis() as i64;
+        assert_eq!(
+            db.defer_op_for_access(op.id, past, past + 5_000).unwrap(),
+            now
+        );
+        db.record_op_failure(op.id, "not writable locally", past + 10_000)
+            .unwrap();
+        let failed = db.pending_ops().unwrap();
+        assert_eq!(failed.len(), 1, "the row and its staged bytes stay queued");
+        assert_eq!(failed[0].attempts, 1);
+        assert_eq!(
+            failed[0].last_error.as_deref(),
+            Some("not writable locally")
+        );
+
+        // Reporting closes the window, so the next deferral starts a fresh one
+        // rather than escalating on every recheck from here on.
+        let after = past + 20_000;
+        assert_eq!(
+            db.defer_op_for_access(op.id, after, after + 5_000).unwrap(),
+            after,
+            "recording the failure re-armed the window"
+        );
+        drop(db);
+        let _ = std::fs::remove_dir_all(dir);
+    }
+
+    /// An op that gets through the access check is no longer blocked, so a
+    /// deferral after it must not inherit the earlier run's age and escalate
+    /// immediately.
+    #[test]
+    fn clearing_the_window_makes_the_next_deferral_a_fresh_run() {
+        use std::sync::atomic::{AtomicU64, Ordering};
+
+        static N: AtomicU64 = AtomicU64::new(0);
+        let dir = std::env::temp_dir().join(format!(
+            "pdfs-drain-defer-clear-{}-{}",
+            std::process::id(),
+            N.fetch_add(1, Ordering::Relaxed)
+        ));
+        std::fs::create_dir_all(&dir).unwrap();
+        let db = Db::open(&dir.join("cache.db")).unwrap();
+        db.enqueue_op(&pending(OP_REVISION)).unwrap();
+        let op = db.pending_ops().unwrap().remove(0);
+
+        let now = 2_000_000i64;
+        assert_eq!(
+            db.defer_op_for_access(op.id, now, now + 5_000).unwrap(),
+            now
+        );
+        db.clear_op_access_deferral(op.id).unwrap();
+        let later = now + DRAIN_ACCESS_DEFER_LIMIT.as_millis() as i64;
+        assert_eq!(
+            db.defer_op_for_access(op.id, later, later + 5_000).unwrap(),
+            later,
+            "the window reopens at the new deferral, not the old one"
+        );
+        drop(db);
+        let _ = std::fs::remove_dir_all(dir);
+    }
+
+    #[test]
+    fn an_authority_the_tree_does_not_have_is_reported_as_unknown_not_deferred() {
+        // The B83 distinction, at the point it is made: a uid with no row must
+        // not come back as `AccessDeferred`, because deferring waits on a
+        // permission change that nothing is going to make. The caller answers
+        // an `AuthorityUnknown` by asking the remote instead.
+        let op = pending(OP_REVISION);
+        let applied = Cell::new(false);
+        let disposition = run_authorized_drain(
+            &op,
+            |_| WriteAuthority::Unknown,
+            || {
+                applied.set(true);
+                Ok(())
+            },
+        )
+        .unwrap();
+        assert_eq!(
+            disposition,
+            DrainDisposition::AuthorityUnknown(parse_node_uid(&op.uid).unwrap())
+        );
+        assert!(!applied.get(), "an unresolved authority never applies");
+    }
+
+    #[test]
+    fn a_missing_parent_authority_names_the_parent_not_the_node() {
+        // A create's authority is its parent, so that is the uid the remote has
+        // to be asked about — reporting the node instead would refetch the
+        // thing that does not exist yet.
+        let mut op = pending(OP_CREATE);
+        let parent = folder_node("vanished-parent", None);
+        op.parent_uid = Some(parent.uid.to_string());
+        let disposition =
+            run_authorized_drain(&op, |_| WriteAuthority::Unknown, || Ok(())).unwrap();
+        assert_eq!(
+            disposition,
+            DrainDisposition::AuthorityUnknown(parent.uid.clone())
+        );
+    }
+
     #[test]
     fn owner_and_editor_drain_authorities_apply_normally() {
         for access in [Access::Owner, Access::Editor] {
             let applied = Cell::new(false);
             let disposition = run_authorized_drain(
                 &pending(OP_REVISION),
-                |_| access.writable().then_some(()).ok_or(fuser::Errno::EACCES),
+                |_| {
+                    if access.writable() {
+                        WriteAuthority::Writable
+                    } else {
+                        WriteAuthority::Denied
+                    }
+                },
                 || {
                     applied.set(true);
                     Ok(())
@@ -1376,3 +1957,42 @@ mod tests {
         assert!(!is_own_self_supersede(true, None, None));
     }
 }
+
+#[cfg(test)]
+mod debounce_tests {
+    use super::*;
+
+    #[test]
+    fn a_node_never_uploaded_keeps_the_fixed_grace_period() {
+        assert_eq!(adaptive_debounce(None), DRAIN_REVISION_DEBOUNCE);
+    }
+
+    #[test]
+    fn a_fast_upload_does_not_shorten_the_grace_period() {
+        // The 2 seconds are not about upload time at all — they are the window
+        // in which a preallocate-then-write tool supersedes its own first
+        // close. A file that sends in 50 ms must still get them.
+        assert_eq!(
+            adaptive_debounce(Some(Duration::from_millis(50))),
+            DRAIN_REVISION_DEBOUNCE
+        );
+    }
+
+    #[test]
+    fn a_slow_upload_widens_the_grace_period_to_match() {
+        // The case the fixed debounce got wrong: saves arriving faster than the
+        // upload completes, each superseding one already on the wire.
+        assert_eq!(
+            adaptive_debounce(Some(Duration::from_secs(25))),
+            Duration::from_secs(25)
+        );
+    }
+
+    #[test]
+    fn a_pathological_upload_cannot_park_a_node() {
+        assert_eq!(
+            adaptive_debounce(Some(Duration::from_secs(6000))),
+            DRAIN_REVISION_DEBOUNCE_MAX
+        );
+    }
+}

crates/pdfs-fuse/src/mount.rs

@@ -255,6 +255,14 @@ pub(super) fn spawn_session(
     root: Node,
 ) -> std::io::Result<BackgroundSession> {
     let mut config = Config::default();
+    // `n_threads` stays at fuser's default of 1 (with `clone_fd` off) on
+    // purpose, for now. A concurrent dispatch loop is worth having, but
+    // `release` currently relies on being serialised against the `open`+`read`
+    // an application issues right after `close(2)` — see the comment on
+    // `Filesystem::release`. Raising it before that ordering is made explicit
+    // (a per-node staging-in-flight barrier) reintroduces the acceptance
+    // suite's "concurrent file 1 mismatch". Kernel-side caps that do *not*
+    // depend on that ordering are negotiated in `ProtonFs::init`.
     config.mount_options = vec![
         MountOption::FSName("protondrive".to_string()),
         MountOption::Subtype("protondrive".to_string()),
@@ -349,23 +357,17 @@ pub fn mount(
     let core = Core {
         client: client.clone(),
         rt: rt.clone(),
+        maintenance: Arc::new(Mutex::new(Default::default())),
         primary_root_uid: root.uid.clone(),
         primary: true,
-        state: Arc::new(Mutex::new(State {
-            entries: HashMap::new(),
-            by_uid: HashMap::new(),
-            children: HashMap::new(),
-            next_ino: 2,
-            active_writes: HashMap::new(),
-            handles: HashMap::new(),
-            next_fh: 1,
-            access_changes: HashSet::new(),
-            share_access,
-            db: db.clone(),
-        })),
+        state: Arc::new(Mutex::new(State::new(db.clone(), share_access, 2))),
         cache: Arc::new(cache),
         readers: Arc::new(Mutex::new(HashMap::new())),
-        stream_ring: Arc::new(Mutex::new(StreamRing::default())),
+        block_ring: Arc::new(Mutex::new(BlockRing::default())),
+        block_flight: Arc::new(BlockFlight::default()),
+        content_repairs: Arc::new(tokio::sync::Mutex::new(HashMap::new())),
+        prefetch: Arc::new(Prefetch::default()),
+        prefetch_budget: Arc::new(tokio::sync::Semaphore::new(PREFETCH_BUDGET)),
         workers: Arc::new(Workers::new(FUSE_WORKERS)?),
         db,
         shared_publication: Arc::new(Mutex::new(())),
@@ -375,6 +377,9 @@ pub fn mount(
         pending: Arc::new(Mutex::new(HashMap::new())),
         hidden: Arc::new(Mutex::new(HashSet::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())),
         timeline_refreshing: Arc::new(AtomicBool::new(false)),
         albums_refreshing: Arc::new(AtomicBool::new(false)),
         trash_refreshing: Arc::new(AtomicBool::new(false)),
@@ -385,7 +390,9 @@ pub fn mount(
         self_changes: Arc::new(Mutex::new(HashMap::new())),
         thumb_gen: Arc::new(Mutex::new(HashSet::new())),
         no_thumbnail: Arc::new(Mutex::new(HashMap::new())),
+        quota: Arc::new(Mutex::new(None)),
         size_upgrades: Arc::new(Mutex::new(HashMap::new())),
+        size_waiters: Arc::new(Default::default()),
         notifier: Arc::new(OnceLock::new()),
         session_live: Arc::new(AtomicBool::new(false)),
         transfers: TransferRegistry::new(),
@@ -407,16 +414,32 @@ pub fn mount(
     // aside at open. After `hydrate_pending`, so a recovered partial write can
     // see an already-queued write to the same node.
     core.recover_fsynced_writes();
-    {
+    // And finally the staged blobs neither of those accounts for: bytes a
+    // failed release left behind with nothing pointing at them.
+    core.reconcile_staging();
+    // Several drain workers over one queue. One thread meant a single large
+    // upload held every queued rename, trash and small write behind it for as
+    // long as it ran; the claim column (`Db::claim_next_due_op`) keeps the
+    // workers off each other's nodes, which is the only ordering the queue
+    // actually needs. Worker 0 additionally runs the queue's idle chores.
+    //
+    // 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).
+    let mut workers: Vec<std::thread::JoinHandle<()>> = Vec::new();
+    for worker in 0..DRAIN_WORKERS {
         let core = core.clone();
-        std::thread::Builder::new()
-            .name("pdfs-drain".into())
-            .spawn(move || core.run_pending_drain())?;
+        workers.push(
+            std::thread::Builder::new()
+                .name(format!("pdfs-drain-{worker}"))
+                .spawn(move || core.run_pending_drain(worker == 0))?,
+        );
     }
 
     // Start the folder-sync engine. It watches every mirror folder, polls the
     // remotes, and reconciles on its own thread — never in front of a FUSE call.
-    sync::spawn(core.clone(), sync_rx);
+    workers.extend(sync::spawn(core.clone(), sync_rx));
 
     // Reconcile leftover `(sync-conflict …)` copies: drop the ones that turned
     // out identical to the live file, surface the ones that genuinely diverge.
@@ -428,18 +451,22 @@ pub fn mount(
     } else {
         info!(mode = ?sweep_mode, "conflict sweep enabled");
         let core = core.clone();
-        std::thread::Builder::new()
-            .name("pdfs-conflict-sweep".into())
-            .spawn(move || core.run_conflict_sweep_loop())?;
+        workers.push(
+            std::thread::Builder::new()
+                .name("pdfs-conflict-sweep".into())
+                .spawn(move || core.run_conflict_sweep_loop())?,
+        );
     }
 
     // Mounted from the cache: watch for the network coming back so the mount can
     // stop being read-only-ish without the user restarting the daemon.
     if !online {
         let core = core.clone();
-        std::thread::Builder::new()
-            .name("pdfs-online-probe".into())
-            .spawn(move || core.run_online_probe())?;
+        workers.push(
+            std::thread::Builder::new()
+                .name("pdfs-online-probe".into())
+                .spawn(move || core.run_online_probe())?,
+        );
     }
 
     // Keep the launcher prompt's "This computer" index fresh. Its own thread:
@@ -449,9 +476,12 @@ pub fn mount(
         let indexing = core.indexing.clone();
         let transfers = core.transfers.clone();
         let mountpoint = mountpoint.to_path_buf();
-        std::thread::Builder::new()
-            .name("pdfs-localindex".into())
-            .spawn(move || run_local_index(db, indexing, transfers, mountpoint))?;
+        let shutdown = core.shutdown.clone();
+        workers.push(
+            std::thread::Builder::new()
+                .name("pdfs-localindex".into())
+                .spawn(move || run_local_index(db, indexing, transfers, mountpoint, shutdown))?,
+        );
     }
 
     // Bind the control socket before the FUSE session takes over the thread. A
@@ -488,23 +518,29 @@ pub fn mount(
         let control_core = core.clone();
         let username = username.clone();
         let mountpoint = mountpoint.to_path_buf();
-        if let Err(error) = std::thread::Builder::new()
+        match std::thread::Builder::new()
             .name("pdfs-control".into())
             .spawn(move || run_control_socket(control_core, username, mountpoint, listener))
         {
-            let secondaries = core.mounts.lock().close_and_drain();
-            for (id, mount) in secondaries {
-                if let Err(unmount_error) = mount.teardown() {
-                    warn!(id, error = %unmount_error, "secondary teardown after control startup failure failed");
+            Ok(handle) => workers.push(handle),
+            Err(error) => {
+                // A failure here abandons the mount, so the background threads
+                // started above have to be told to stop with it.
+                stop_workers(&core, control_socket, workers);
+                let secondaries = core.mounts.lock().close_and_drain();
+                for (id, mount) in secondaries {
+                    if let Err(unmount_error) = mount.teardown() {
+                        warn!(id, error = %unmount_error, "secondary teardown after control startup failure failed");
+                    }
                 }
+                if let Err(unmount_error) = teardown_session(&core.session_live, || {
+                    umount_session_unblocked(bg, main_conn)
+                }) {
+                    warn!(error = %unmount_error, "unmount after control startup failure failed");
+                }
+                let _ = std::fs::remove_file(control_socket);
+                return Err(error);
             }
-            if let Err(unmount_error) = teardown_session(&core.session_live, || {
-                umount_session_unblocked(bg, main_conn)
-            }) {
-                warn!(error = %unmount_error, "unmount after control startup failure failed");
-            }
-            let _ = std::fs::remove_file(control_socket);
-            return Err(error);
         }
     }
     // Re-establish on-demand mounts only after the primary session is live.
@@ -613,10 +649,43 @@ pub fn mount(
         }
     }
 
-    let _ = std::fs::remove_file(control_socket);
+    // 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)
 }
 
+/// Signal every background loop, wake the ones that are blocked, and join them.
+///
+/// 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).
+///
+/// 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.
+fn stop_workers(core: &Core, control_socket: &Path, workers: Vec<std::thread::JoinHandle<()>>) {
+    core.shutdown.stop();
+    core.wake_drain();
+    let _ = core.sync_tx.send(sync::SyncMsg::Stop);
+    // Connect while the socket still exists — that is the whole point of the
+    // poke — then unlink it so nothing else can arrive behind us. The listener
+    // re-checks the flag after every accept, so even a connection that races the
+    // 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 {
+        if worker.join().is_err() {
+            warn!("a background worker panicked before shutdown");
+        }
+    }
+    debug!("background workers stopped");
+}
+
 #[cfg(test)]
 mod tests {
     use std::sync::atomic::{AtomicBool, Ordering};

crates/pdfs-fuse/src/profile.rs

@@ -149,10 +149,10 @@ impl Core {
             .pin_list()
             .map_err(|e| CoreError::internal(format!("db: {e:?}")))?
             .into_iter()
-            .map(|(uid, path, recursive)| ProfilePin {
-                uid,
-                path,
-                recursive,
+            .map(|row| ProfilePin {
+                uid: row.uid,
+                path: row.path,
+                recursive: row.recursive,
             })
             .collect();
         let cfg = pdfs_core::config::AppDirs::new()

crates/pdfs-fuse/src/sharing.rs

@@ -12,6 +12,9 @@ use pdfs_core::control::{
     BookmarkInfo, DirEntry, InvitationInfo, PublicLinkInfo, ShareEntry, ShareEntryKind, SharedItem,
 };
 use pdfs_core::{CoreError, CoreResult};
+use tracing::debug;
+
+use crate::QUOTA_TTL;
 use proton_drive_rs::proton_sdk::ids::NodeUid;
 use proton_drive_rs::{MemberRole, NodeKind};
 
@@ -533,9 +536,33 @@ impl Core {
             .rt
             .block_on(self.client.quota())
             .map_err(|e| CoreError::from_api(&e, "account quota"))?;
+        *self.quota.lock() = Some((std::time::Instant::now(), q.max_space, q.used_space));
         Ok((q.max_space, q.used_space))
     }
 
+    /// The account quota as `statfs(2)` needs it: cached for [`QUOTA_TTL`],
+    /// refetched after that, and `None` when there is no usable answer at all —
+    /// offline with nothing cached.
+    ///
+    /// Never blocks on the network for a *fresh* value when a recent one exists,
+    /// because the callers are `df` and every "is there room?" preflight, and a
+    /// stale byte count is worth more to them than a stalled syscall. Offline,
+    /// the last known figures keep being served rather than degrading to zero.
+    pub(crate) fn account_quota_cached(&self) -> Option<(i64, i64)> {
+        if let Some((at, max_space, used_space)) = *self.quota.lock()
+            && at.elapsed() < QUOTA_TTL
+        {
+            return Some((max_space, used_space));
+        }
+        match self.account_quota() {
+            Ok(q) => Some(q),
+            Err(error) => {
+                debug!(%error, "account quota refresh failed; serving the last known figures");
+                self.quota.lock().map(|(_, max, used)| (max, used))
+            }
+        }
+    }
+
     // ---- shared by me -----------------------------------------------------
 
     /// List the nodes I have shared with others, each with a summary of its share

crates/pdfs-fuse/src/shutdown.rs

@@ -0,0 +1,96 @@
+//! One shutdown signal shared by every long-lived worker in the daemon.
+//!
+//! The mount used to end by unmounting and returning, leaving the drain
+//! workers, the sync engine, the conflict sweep, the online probe and the local
+//! indexer running on `Core` clones. In a process that exits immediately that is
+//! 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).
+//!
+//! The primitive is deliberately small: a flag plus a condvar. Every loop that
+//! would otherwise call `thread::sleep` calls [`Shutdown::sleep`] instead, which
+//! returns early — and reports `false` — the moment [`Shutdown::stop`] is
+//! called, so teardown does not have to wait out a five-minute sweep interval to
+//! join a thread.
+
+use std::time::Duration;
+
+use parking_lot::{Condvar, Mutex};
+
+/// The daemon's stop signal. Set once, never cleared: a `Core` that has been
+/// told to stop belongs to a mount that is going away.
+#[derive(Default)]
+pub(crate) struct Shutdown {
+    stopping: Mutex<bool>,
+    changed: Condvar,
+}
+
+impl Shutdown {
+    /// Whether teardown has begun. Loops check this where they would otherwise
+    /// start another unit of work.
+    pub(crate) fn is_stopping(&self) -> bool {
+        *self.stopping.lock()
+    }
+
+    /// Begin teardown and wake everything waiting in [`sleep`](Self::sleep).
+    /// Idempotent, because more than one path can reach teardown (a signal, the
+    /// kernel mount ending, a failed startup).
+    pub(crate) fn stop(&self) {
+        let mut stopping = self.stopping.lock();
+        *stopping = true;
+        self.changed.notify_all();
+    }
+
+    /// Wait up to `duration`, or until teardown starts.
+    ///
+    /// Returns `false` if the daemon is stopping — including when it was already
+    /// stopping on entry, so `while shutdown.sleep(interval)` is a complete and
+    /// correct loop condition and no separate check is needed at the top.
+    pub(crate) fn sleep(&self, duration: Duration) -> bool {
+        let mut stopping = self.stopping.lock();
+        if !*stopping {
+            self.changed.wait_for(&mut stopping, duration);
+        }
+        !*stopping
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::Arc;
+    use std::time::Instant;
+
+    #[test]
+    fn sleeping_returns_early_once_stopped() {
+        let shutdown = Arc::new(Shutdown::default());
+        assert!(!shutdown.is_stopping());
+
+        let waker = shutdown.clone();
+        std::thread::spawn(move || {
+            std::thread::sleep(Duration::from_millis(20));
+            waker.stop();
+        });
+
+        let started = Instant::now();
+        // An hour's worth of interval, cut short by the stop.
+        assert!(!shutdown.sleep(Duration::from_secs(3600)));
+        assert!(
+            started.elapsed() < Duration::from_secs(5),
+            "stop must interrupt the wait, not wait it out"
+        );
+        assert!(shutdown.is_stopping());
+        // Already stopping: the next wait does not sleep at all.
+        let started = Instant::now();
+        assert!(!shutdown.sleep(Duration::from_secs(3600)));
+        assert!(started.elapsed() < Duration::from_secs(5));
+    }
+
+    #[test]
+    fn sleeping_runs_to_the_timeout_while_running() {
+        let shutdown = Shutdown::default();
+        assert!(shutdown.sleep(Duration::from_millis(10)));
+        assert!(!shutdown.is_stopping());
+    }
+}

crates/pdfs-fuse/src/state.rs

@@ -141,6 +141,11 @@ pub(crate) struct PendingRevision {
     pub(crate) meta: StagedWrite,
 }
 
+/// One directory's entries as `readdir` reports them: `(ino, is_dir, name)` per
+/// entry, in reply order. The kernel's file-type enum is mapped in at reply
+/// time so this module stays free of `fuser`.
+pub(crate) type DirListing = Vec<(u64, bool, String)>;
+
 /// Mutable inode bookkeeping, guarded by a mutex because fuser drives the
 /// `Filesystem` trait through `&self`.
 pub(crate) struct State {
@@ -158,6 +163,16 @@ pub(crate) struct State {
     /// have no entry here.
     pub(crate) handles: HashMap<u64, u64>,
     pub(crate) next_fh: u64,
+    /// One frozen listing per open directory handle, taken at `opendir`.
+    ///
+    /// `readdir` resumes from a byte offset into the listing it is walking, so
+    /// that listing has to stay the same across the calls of one `getdents`
+    /// sequence. Rebuilding it live meant a create or a trash landing between
+    /// 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).
+    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.
@@ -166,13 +181,164 @@ pub(crate) struct State {
     /// 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>,
-    /// Unified SQLite metadata cache. Every map mutation below writes through to
-    /// it inside the `State` lock so the DB stays the authoritative copy across
-    /// restarts (see plan.md P1).
+    /// Unified SQLite metadata cache. Read from here (`has_children`) but never
+    /// written: mutations go to [`State::outbox`] and are applied after the lock
+    /// is released. See [`StateGuard`].
     pub(crate) db: Arc<Db>,
+    /// Write-throughs this mutation owes SQLite, applied by [`StateGuard`] once
+    /// the inode lock is released.
+    ///
+    /// The DB stays the authoritative copy across restarts, so every map
+    /// mutation still writes through — it just no longer does so with the
+    /// whole-mount lock held. A single listing's write-through is one
+    /// transaction over up to a few thousand rows, and every other FUSE callback
+    /// used to wait behind it for no reason: the maps were already updated
+    /// before the first row was written.
+    outbox: Vec<DbWrite>,
+}
+
+/// A write-through queued by a `State` mutation, applied after the lock drops.
+///
+/// Deliberately a small closed set rather than a boxed closure: these run
+/// outside the lock, and what they can touch should be readable here.
+pub(crate) enum DbWrite {
+    /// One node or a whole listing. Both go through `upsert_nodes`, which is a
+    /// single transaction either way, so there is nothing to gain by splitting
+    /// them — and a `Node` is large enough that a variant holding one inline
+    /// would set the size of every other.
+    Upsert(Vec<Node>),
+    Delete(NodeUid),
+    SetListed(NodeUid, bool),
+    SetShareAccess(NodeUid, Access),
+}
+
+impl DbWrite {
+    fn apply(self, db: &Db) {
+        let outcome = match &self {
+            Self::Upsert(nodes) => db.upsert_nodes(nodes),
+            Self::Delete(uid) => db.delete_node(uid),
+            Self::SetListed(uid, listed) => db.set_listed(uid, *listed),
+            Self::SetShareAccess(uid, access) => db.set_share_access(uid, *access),
+        };
+        if let Err(error) = outcome {
+            let what = match &self {
+                Self::Upsert(_) => "upsert_nodes",
+                Self::Delete(_) => "delete_node",
+                Self::SetListed(..) => "set_listed",
+                Self::SetShareAccess(..) => "set_share_access",
+            };
+            warn!(%error, write = what, "db write-through failed");
+        }
+    }
+}
+
+/// The inode lock, held for the duration of a mutation, plus the write-throughs
+/// that mutation owed the database.
+///
+/// Dropping it releases the lock *first* and only then writes, which is the
+/// whole point: interning a five-thousand-child listing commits one transaction
+/// — several fsyncs' worth — and nothing about that needs the maps frozen. The
+/// write still happens synchronously on this thread before the caller proceeds,
+/// so a read that follows a mutation still sees it.
+pub(crate) struct StateGuard<'a> {
+    guard: Option<parking_lot::MutexGuard<'a, State>>,
+    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 {
+            guard: Some(guard),
+            db,
+        }
+    }
+}
+
+impl std::ops::Deref for StateGuard<'_> {
+    type Target = State;
+
+    fn deref(&self) -> &State {
+        self.guard.as_ref().expect("held until drop")
+    }
+}
+
+impl std::ops::DerefMut for StateGuard<'_> {
+    fn deref_mut(&mut self) -> &mut State {
+        self.guard.as_mut().expect("held until drop")
+    }
+}
+
+impl Drop for StateGuard<'_> {
+    fn drop(&mut self) {
+        let Some(mut guard) = self.guard.take() else {
+            return;
+        };
+        let writes = std::mem::take(&mut guard.outbox);
+        // The lock goes before the writes do. That ordering is the feature.
+        drop(guard);
+        for write in writes {
+            write.apply(self.db);
+        }
+    }
 }
 
 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
+    /// first and then applies them, which is the whole point. A test driving a
+    /// bare `State` has no guard, so it calls this where the daemon would have
+    /// dropped one.
+    #[cfg(test)]
+    pub(crate) fn flush_outbox(&mut self) {
+        let db = self.db.clone();
+        for write in std::mem::take(&mut self.outbox) {
+            write.apply(&db);
+        }
+    }
+
+    /// The database, with everything this state owes it already written.
+    ///
+    /// What a test means by `st.db` is almost always "the database as of now",
+    /// which in the daemon is the state after the guard dropped. Handing back an
+    /// owned `Arc` rather than a borrow keeps it usable inside an `assert_eq!`
+    /// that also touches `st`.
+    #[cfg(test)]
+    pub(crate) fn flushed_db(&mut self) -> Arc<Db> {
+        self.flush_outbox();
+        self.db.clone()
+    }
+
+    pub(crate) fn new(db: Arc<Db>, share_access: HashMap<NodeUid, Access>, next_ino: u64) -> Self {
+        Self {
+            entries: HashMap::new(),
+            by_uid: HashMap::new(),
+            children: HashMap::new(),
+            next_ino,
+            active_writes: HashMap::new(),
+            handles: HashMap::new(),
+            next_fh: 1,
+            dir_snapshots: HashMap::new(),
+            access_changes: HashSet::new(),
+            share_access,
+            db,
+            outbox: Vec::new(),
+        }
+    }
     /// Whether `uid` names an owned node currently reachable from this mount's
     /// root. Resident entries can outlive their dentries for open-handle and
     /// access-revocation semantics, so `by_uid` membership alone is not proof
@@ -278,11 +444,9 @@ impl State {
                 || stored.unwrap_or(Access::Viewer),
                 |membership| access_for(membership.role_exact(), parent_access, true),
             );
-            if let Err(error) = self.db.set_share_access(&node.uid, access) {
-                warn!(uid = %node.uid, ?access, %error, "db set_share_access failed");
-            } else {
-                self.share_access.insert(node.uid.clone(), access);
-            }
+            self.outbox
+                .push(DbWrite::SetShareAccess(node.uid.clone(), access));
+            self.share_access.insert(node.uid.clone(), access);
             return access;
         }
         parent_access
@@ -313,11 +477,9 @@ impl State {
             None => (None, Access::Unknown),
         };
         let access = access_for(role, parent_access, true);
-        if let Err(error) = self.db.set_share_access(uid, access) {
-            warn!(%uid, ?access, %error, "db set observed share access failed");
-        } else {
-            self.share_access.insert(uid.clone(), access);
-        }
+        self.outbox
+            .push(DbWrite::SetShareAccess(uid.clone(), access));
+        self.share_access.insert(uid.clone(), access);
         let Some(root) = root else {
             return Vec::new();
         };
@@ -602,18 +764,14 @@ impl State {
             })
             .collect();
         for (uid, access) in discovered {
-            if let Err(error) = self.db.set_share_access(&uid, access) {
-                warn!(%uid, ?access, %error, "db set hydrated share access failed");
-            } else {
-                self.share_access.insert(uid, access);
-            }
+            self.outbox
+                .push(DbWrite::SetShareAccess(uid.clone(), access));
+            self.share_access.insert(uid, access);
         }
     }
 
     pub(crate) fn intern(&mut self, parent: u64, node: Node) -> u64 {
-        if let Err(e) = self.db.upsert_node(&node) {
-            warn!(uid = %node.uid, error = %e, "db upsert_node failed");
-        }
+        self.outbox.push(DbWrite::Upsert(vec![node.clone()]));
         self.intern_mem(parent, node)
     }
 
@@ -685,9 +843,7 @@ 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> {
-        if let Err(e) = self.db.upsert_nodes(&nodes) {
-            warn!(error = %e, "db upsert_nodes failed");
-        }
+        self.outbox.push(DbWrite::Upsert(nodes.clone()));
         nodes
             .into_iter()
             .map(|node| self.intern_mem(parent, node))
@@ -769,9 +925,7 @@ impl State {
     /// `(parent_ino, name)` when the node was known, so the caller can notify
     /// the kernel.
     pub(crate) fn forget(&mut self, uid: &NodeUid) -> Option<(u64, String)> {
-        if let Err(e) = self.db.delete_node(uid) {
-            warn!(%uid, error = %e, "db delete_node failed");
-        }
+        self.outbox.push(DbWrite::Delete(uid.clone()));
         self.forget_mem(uid)
     }
 
@@ -834,9 +988,7 @@ impl State {
                 kids.push(ino);
             }
         }
-        if let Err(e) = self.db.upsert_node(&node) {
-            warn!(uid = %node.uid, error = %e, "db upsert_node failed for a queued rename");
-        }
+        self.outbox.push(DbWrite::Upsert(vec![node]));
         self.recompute_descendant_access(ino);
     }
 
@@ -851,9 +1003,7 @@ impl State {
         self.children.remove(&ino);
         if let Some(e) = self.entries.get(&ino) {
             let uid = e.uid.clone();
-            if let Err(err) = self.db.set_listed(&uid, false) {
-                warn!(%uid, error = %err, "db set_listed(false) failed");
-            }
+            self.outbox.push(DbWrite::SetListed(uid, false));
         }
     }
 
@@ -920,14 +1070,15 @@ impl State {
     /// 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).
-    pub(crate) fn record_pending_write(&mut self, ino: u64, size: u64, mtime: i64) {
+    /// 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
+    /// the daemon acknowledged a write and then serves the old size for it, so
+    /// the caller has to be able to turn it into a failed `release`.
+    pub(crate) fn record_pending_write(&mut self, ino: u64, size: u64, mtime: i64) -> Option<Node> {
         self.set_size(ino, size);
         self.touch_mtime(ino, mtime);
-        if let Some(e) = self.entries.get(&ino)
-            && let Err(err) = self.db.upsert_node(&e.node)
-        {
-            warn!(uid = %e.uid, error = %err, "db upsert_node failed for a queued write");
-        }
+        self.entries.get(&ino).map(|e| e.node.clone())
     }
 }
 
@@ -1008,18 +1159,7 @@ 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 {
-            entries: HashMap::new(),
-            by_uid: HashMap::new(),
-            children: HashMap::new(),
-            next_ino: 1,
-            active_writes: HashMap::new(),
-            handles: HashMap::new(),
-            next_fh: 1,
-            access_changes: HashSet::new(),
-            share_access,
-            db: Arc::new(db),
-        };
+        let st = State::new(Arc::new(db), share_access, 1);
         (st, dir)
     }
 
@@ -1032,8 +1172,8 @@ mod tests {
         let f = st.intern(src, node("f", "src", "f.txt", false));
         st.children.insert(src, vec![f]);
         st.children.insert(dst, vec![]);
-        st.db.set_listed(&uid("src"), true).unwrap();
-        st.db.set_listed(&uid("dst"), true).unwrap();
+        st.flushed_db().set_listed(&uid("src"), true).unwrap();
+        st.flushed_db().set_listed(&uid("dst"), true).unwrap();
         (st, dir, src, dst)
     }
 
@@ -1047,11 +1187,17 @@ mod tests {
         st.relocate(f, src, dst, &uid("dst"), "f.txt");
 
         assert!(
-            st.db.children_if_listed(&uid("dst")).unwrap().is_none(),
+            st.flushed_db()
+                .children_if_listed(&uid("dst"))
+                .unwrap()
+                .is_none(),
             "destination re-enumerates: it gained a child whose row was just deleted"
         );
         assert!(
-            st.db.children_if_listed(&uid("src")).unwrap().is_none(),
+            st.flushed_db()
+                .children_if_listed(&uid("src"))
+                .unwrap()
+                .is_none(),
             "source re-enumerates: its listing predates the move, and a stale \
              `listed` flag would hide every later remote change under it"
         );
@@ -1074,12 +1220,41 @@ mod tests {
         let (mut st, _dir, src, _dst) = two_folders();
         let f = st.by_uid[&uid("f")];
         st.relocate(f, src, src, &uid("src"), "renamed.txt");
-        assert!(st.db.children_if_listed(&uid("src")).unwrap().is_none());
+        assert!(
+            st.flushed_db()
+                .children_if_listed(&uid("src"))
+                .unwrap()
+                .is_none()
+        );
         assert!(!st.children.contains_key(&src));
         assert_eq!(st.by_uid.get(&uid("f")), Some(&f), "the inode is stable");
         assert_eq!(st.entries[&f].node.name, "renamed.txt");
     }
 
+    /// DB1: a mutation's write-through must not happen with the inode lock
+    /// held. Interning a listing commits a transaction over every child, and
+    /// every other FUSE callback used to wait behind that for no reason — the
+    /// maps it needs were updated before the first row was written.
+    #[test]
+    fn a_mutation_writes_through_only_after_the_lock_is_released() {
+        let (st, _dir) = state();
+        let db = st.db.clone();
+        let root = uid("root").to_string();
+        let state = parking_lot::Mutex::new(st);
+        {
+            let mut guard = lock_state(&state, &db);
+            guard.intern(0, node("root", "none", "My Files", true));
+            assert!(
+                db.node_by_uid(&root).unwrap().is_none(),
+                "the row must not be written while the lock is held"
+            );
+        }
+        assert!(
+            db.node_by_uid(&root).unwrap().is_some(),
+            "…and must be written by the time the guard is gone"
+        );
+    }
+
     /// The failure mode the fix exists for, stated directly: forgetting the node
     /// prunes it from the resident listing but leaves the DB claiming the source
     /// is fully enumerated. This pins *why* `relocate` cannot just call `forget`.
@@ -1087,7 +1262,7 @@ mod tests {
     fn forget_alone_leaves_the_source_claiming_a_complete_listing() {
         let (mut st, _dir, _src, _dst) = two_folders();
         st.forget(&uid("f"));
-        let listed = st.db.children_if_listed(&uid("src")).unwrap();
+        let listed = st.flushed_db().children_if_listed(&uid("src")).unwrap();
         assert!(
             listed.is_some(),
             "forget does not clear the flag — which is exactly why relocate must"
@@ -1136,7 +1311,7 @@ mod tests {
         assert!(!st.has_children(folder), "cleared memory children");
 
         // DB children
-        st.db
+        st.flushed_db()
             .upsert_node(&node("file2_uid", "dir_uid", "file2.txt", false))
             .unwrap();
         assert!(
@@ -1162,7 +1337,7 @@ mod tests {
         assert_eq!(st.entries[&shared_ino].access, Access::Editor);
         assert_eq!(st.entries[&child].access, Access::Editor);
         assert_eq!(
-            st.db.share_access(&uid("shared")).unwrap(),
+            st.flushed_db().share_access(&uid("shared")).unwrap(),
             Some(Access::Editor)
         );
     }
@@ -1174,8 +1349,8 @@ mod tests {
         let virtual_uid = NodeUid::new(VolumeId::from("virtual"), LinkId::from("sharedwithme"));
         let mut virtual_root = node("placeholder", "root", "Shared with me", true);
         virtual_root.uid = virtual_uid.clone();
-        st.db.upsert_node(&virtual_root).unwrap();
-        st.db
+        st.flushed_db().upsert_node(&virtual_root).unwrap();
+        st.flushed_db()
             .set_share_access(&virtual_uid, Access::Viewer)
             .unwrap();
         let virtual_ino = st.intern_published_share_root(owned_root, virtual_root, Access::Viewer);
@@ -1183,15 +1358,17 @@ mod tests {
         let mut shared = node("shared", "placeholder", "Retained", true);
         shared.parent_uid = Some(virtual_uid.clone());
         shared.membership = Some(membership(6));
-        st.db.upsert_node(&shared).unwrap();
-        st.db.set_share_access(&shared.uid, Access::Editor).unwrap();
+        st.flushed_db().upsert_node(&shared).unwrap();
+        st.flushed_db()
+            .set_share_access(&shared.uid, Access::Editor)
+            .unwrap();
         let shared_ino =
             st.intern_published_share_root(virtual_ino, shared.clone(), Access::Editor);
         let child = st.intern(
             shared_ino,
             node("shared-child", "shared", "pending.txt", false),
         );
-        st.db
+        st.flushed_db()
             .enqueue_op(&pdfs_core::db::PendingOp {
                 id: 0,
                 kind: pdfs_core::db::OP_RENAME.to_string(),
@@ -1209,20 +1386,20 @@ mod tests {
         assert_eq!(st.entries[&shared_ino].access, Access::Editor);
         assert_eq!(st.entries[&child].access, Access::Editor);
 
-        st.db
+        st.flushed_db()
             .publish_shared_roots(&virtual_uid, std::slice::from_ref(&shared.uid), &[])
             .unwrap();
-        let snapshot = st.db.visible_children(&virtual_uid).unwrap();
+        let snapshot = st.flushed_db().visible_children(&virtual_uid).unwrap();
         assert_eq!(snapshot.len(), 1);
         st.intern_published_share_root(virtual_ino, snapshot[0].clone(), Access::Viewer);
 
         assert_eq!(
-            st.db.share_access(&shared.uid).unwrap(),
+            st.flushed_db().share_access(&shared.uid).unwrap(),
             Some(Access::Viewer)
         );
         assert_eq!(st.entries[&shared_ino].access, Access::Viewer);
         assert_eq!(st.entries[&child].access, Access::Viewer);
-        assert_eq!(st.db.pending_ops().unwrap().len(), 1);
+        assert_eq!(st.flushed_db().pending_ops().unwrap().len(), 1);
     }
 
     #[test]
@@ -1233,12 +1410,12 @@ mod tests {
         let child_node = node("offline-child", "offline-share", "nested folder", true);
         let leaf_node = node("offline-leaf", "offline-child", "child.txt", false);
         for node in [&root_node, &shared_node, &child_node, &leaf_node] {
-            st.db.upsert_node(node).unwrap();
+            st.flushed_db().upsert_node(node).unwrap();
         }
-        st.db
+        st.flushed_db()
             .set_share_access(&uid("offline-share"), Access::Viewer)
             .unwrap();
-        st.share_access = st.db.all_share_access().unwrap();
+        st.share_access = st.flushed_db().all_share_access().unwrap();
 
         // Reconstruct in deliberately non-topological order, matching the
         // database hydration path that first allocates every inode and only
@@ -1296,7 +1473,7 @@ mod tests {
     /// `ORPHAN_INO`. `nodes[0]` becomes the mount root.
     fn hydrate_from(st: &mut State, nodes: &[Node]) -> Vec<u64> {
         for node in nodes {
-            st.db.upsert_node(node).unwrap();
+            st.flushed_db().upsert_node(node).unwrap();
         }
         let inos: Vec<u64> = nodes
             .iter()
@@ -1394,10 +1571,10 @@ mod tests {
     #[test]
     fn persisted_authority_outranks_the_own_volume_fail_open() {
         let (mut st, _dir) = state();
-        st.db
+        st.flushed_db()
             .set_share_access(&uid("device-root"), Access::Viewer)
             .unwrap();
-        st.share_access = st.db.all_share_access().unwrap();
+        st.share_access = st.flushed_db().all_share_access().unwrap();
         let nodes = [
             node("root", "none", "My Files", true),
             node("documents", "device-root", "Documents", true),
@@ -1431,7 +1608,7 @@ mod tests {
             assert_eq!(st.require_writable(ino).unwrap_err().code(), libc::EACCES);
         }
         assert_eq!(
-            st.db.share_access(&uid("shared")).unwrap(),
+            st.flushed_db().share_access(&uid("shared")).unwrap(),
             Some(Access::Viewer)
         );
     }
@@ -1441,8 +1618,10 @@ mod tests {
         for persisted in [Access::Viewer, Access::Editor] {
             let (mut st, _dir) = state();
             let owned_root = st.intern(0, node("root", "none", "My Files", true));
-            st.db.set_share_access(&uid("shared"), persisted).unwrap();
-            st.share_access = st.db.all_share_access().unwrap();
+            st.flushed_db()
+                .set_share_access(&uid("shared"), persisted)
+                .unwrap();
+            st.share_access = st.flushed_db().all_share_access().unwrap();
             let shared = st.intern(
                 owned_root,
                 node("shared", "root", "Shared without membership", true),
@@ -1454,7 +1633,10 @@ mod tests {
 
             assert_eq!(st.entries[&shared].access, persisted);
             assert_eq!(st.entries[&child].access, persisted);
-            assert_eq!(st.db.share_access(&uid("shared")).unwrap(), Some(persisted));
+            assert_eq!(
+                st.flushed_db().share_access(&uid("shared")).unwrap(),
+                Some(persisted)
+            );
         }
     }
 
@@ -1462,7 +1644,7 @@ mod tests {
     fn explicit_missing_share_role_fails_closed_and_marks_kernel_attrs() {
         let (mut st, _dir) = state();
         let owned_root = st.intern(0, node("root", "none", "My Files", true));
-        st.db
+        st.flushed_db()
             .set_share_access(&uid("shared"), Access::Editor)
             .unwrap();
         let shared = st.intern(owned_root, node("shared", "root", "Shared", true));
@@ -1474,7 +1656,7 @@ mod tests {
         assert_eq!(st.entries[&shared].access, Access::Viewer);
         assert_eq!(st.entries[&child].access, Access::Viewer);
         assert_eq!(
-            st.db.share_access(&uid("shared")).unwrap(),
+            st.flushed_db().share_access(&uid("shared")).unwrap(),
             Some(Access::Viewer)
         );
         assert!(changed.contains(&shared));
@@ -1491,7 +1673,7 @@ mod tests {
         let virtual_uid = NodeUid::new(VolumeId::from("virtual"), LinkId::from("sharedwithme"));
         let mut virtual_node = node("sharedwithme", "root", "Shared with me", true);
         virtual_node.uid = virtual_uid.clone();
-        st.db
+        st.flushed_db()
             .set_share_access(&virtual_uid, Access::Viewer)
             .unwrap();
         st.share_access.insert(virtual_uid.clone(), Access::Viewer);
@@ -1558,7 +1740,7 @@ mod tests {
         let child = st.intern(shared, node("child", "shared", "folder", true));
         let leaf = st.intern(child, node("leaf", "child", "leaf.txt", false));
 
-        st.db
+        st.flushed_db()
             .set_share_access(&uid("shared"), Access::Viewer)
             .unwrap();
         let changed = st.downgrade_shared_subtree(&uid("shared"));
@@ -1572,7 +1754,7 @@ mod tests {
         assert_eq!(st.entries[&leaf].access, Access::Viewer);
         assert_eq!(st.require_writable(leaf).unwrap_err().code(), libc::EACCES);
         assert_eq!(
-            st.db.effective_node_access(&uid("leaf")).unwrap(),
+            st.flushed_db().effective_node_access(&uid("leaf")).unwrap(),
             Some(Access::Viewer)
         );
 
@@ -1628,7 +1810,7 @@ mod tests {
         let shared = st.intern(owned_root, shared_node);
         let shared_child = st.intern(shared, node("child", "shared", "child.txt", false));
 
-        st.db.downgrade_all_share_access().unwrap();
+        st.flushed_db().downgrade_all_share_access().unwrap();
         let changed = st.downgrade_known_shared_access();
 
         assert!(changed.contains(&shared));
@@ -1652,7 +1834,7 @@ mod tests {
             let parent_link = st.entries[&parent].uid.link_id.to_string();
             parent = st.intern(parent, node(&link, &parent_link, &link, true));
         }
-        st.db.downgrade_all_share_access().unwrap();
+        st.flushed_db().downgrade_all_share_access().unwrap();
 
         let changed = st.downgrade_known_shared_access();
 

crates/pdfs-fuse/src/sweep.rs

@@ -67,10 +67,16 @@ impl Core {
     /// Sweep for stale conflict copies forever, on its own thread. See the module
     /// docs for the identical/divergent policy.
     pub(crate) fn run_conflict_sweep_loop(&self) {
-        std::thread::sleep(CONFLICT_SWEEP_WARMUP);
+        // Both waits are interruptible, so teardown does not have to sit out a
+        // five-minute interval to join this thread (bugs.md B44).
+        if !self.shutdown.sleep(CONFLICT_SWEEP_WARMUP) {
+            return;
+        }
         loop {
             self.sweep_conflicts_once();
-            std::thread::sleep(CONFLICT_SWEEP_INTERVAL);
+            if !self.shutdown.sleep(CONFLICT_SWEEP_INTERVAL) {
+                return;
+            }
         }
     }
 
@@ -138,9 +144,9 @@ impl Core {
     /// enumerated every node up front and has been doing network I/O since. Before
     /// touching anything remote this re-reads the node and refuses to act unless
     /// it is *still* the same revision, still untrashed, still unwritten and still
-    /// unopened. Without that, a user edit landing inside the window is destroyed
-    /// — `discard_queued_ops` below drops the queued write *and its staged blob*,
-    /// which may hold the only copy of those bytes (`docs/BUGS.md` B71).
+    /// unopened (`docs/BUGS.md` B71). Nothing on this path discards a queued write
+    /// or its staged blob: a write that arrives after that check is left for the
+    /// drain to resolve against the now-trashed node.
     fn remove_conflict_copy(&self, snapshot: &proton_drive_rs::Node, base: &str) {
         let uid = &snapshot.uid;
         let name = snapshot.name.as_str();
@@ -166,10 +172,13 @@ impl Core {
         self.for_each_state(|st| {
             st.forget_or_unlink(uid);
         });
-        if let Err(error) = self.discard_queued_ops(uid) {
-            warn!(%uid, ?error, "conflict sweep: queued-op cleanup failed");
-            return;
-        }
+        // Deliberately *not* `discard_queued_ops`: `duplicate_still_removable`
+        // proved the queue empty before the trash above, but that proof is stale
+        // the moment `trash_nodes` goes to the network. A `close(2)` landing in
+        // that window stages bytes, and discarding here would unlink the staged
+        // blob holding the only copy of them. Leaving the op queued is the
+        // non-destructive outcome: the drain re-reads the node, sees it trashed,
+        // and `revision_conflict` routes it to `keep_as_conflict_copy`.
         self.cache.evict(uid);
         self.evict_reader(uid);
         if let Err(e) = self.db.delete_node(uid) {
@@ -194,8 +203,8 @@ impl Core {
         let uid = &snapshot.uid;
         let name = snapshot.name.as_str();
 
-        // A queued op means bytes are still owed an upload. `discard_queued_ops`
-        // would throw those away along with the staged blob holding them.
+        // A queued op means bytes are still owed an upload; trashing the node
+        // under them turns an ordinary upload into a conflict fork.
         match self.db.has_any_op(&uid.to_string()) {
             Ok(false) => {}
             Ok(true) => {

crates/pdfs-fuse/src/sync.rs

@@ -54,7 +54,7 @@ use engine::{classify, settle_with};
 #[cfg(test)]
 use local_scan::is_write_mode;
 use local_scan::open_for_write_set;
-use model::{LocalItem, Outcome, PassAbort, Pending, RemoteItem};
+use model::{LocalItem, LocalSig, Outcome, PassAbort, Pending, RemoteItem};
 pub(crate) use planner::base_name;
 #[cfg(test)]
 use planner::conflict_path;
@@ -525,6 +525,9 @@ impl Core {
                 continue;
             }
             trashed.push(rel.clone());
+            if let Some(parent) = parent_uid_of(rel, &remote_dirs, &baseline) {
+                self.invalidate_children_of(&parent);
+            }
             let _ = self.db.sync_entry_remove(folder_id, rel);
             self.log_activity(
                 ActivityKind::Trash,
@@ -687,6 +690,7 @@ impl Core {
                             rel_path: rel.clone(),
                             remote_uid: Some(remote.uid.to_string()),
                             local_mtime: local.mtime,
+                            local_mtime_ns: local.mtime_ns,
                             local_size: local.size,
                             remote_rev: Some(remote.mtime.to_string()),
                             remote_hash: Some(remote.size.to_string()),
@@ -717,6 +721,9 @@ impl Core {
                         uid: remote.uid.clone(),
                         mtime: remote.mtime,
                         size: remote.size,
+                        // What the walk saw here, so the apply step can tell a
+                        // stale plan from a live one before it overwrites.
+                        local: l.map(LocalSig::from),
                     });
                 }
                 FilePlan::Conflict => {
@@ -739,7 +746,9 @@ impl Core {
                     }
                 },
                 FilePlan::DeleteLocal => {
-                    if let Err(e) = std::fs::remove_file(local_root.join(rel_to_path(rel))) {
+                    if let Err(e) =
+                        removed_locally(std::fs::remove_file(local_root.join(rel_to_path(rel))))
+                    {
                         warn!(rel, error = %e, "sync: remove local file failed");
                         self.log_activity(
                             ActivityKind::Trash,
@@ -771,6 +780,9 @@ impl Core {
                         outcome.errors += 1;
                         continue;
                     }
+                    if let Some(parent) = parent_uid_of(rel, &remote_dirs, &baseline) {
+                        self.invalidate_children_of(&parent);
+                    }
                     let _ = self.db.sync_entry_remove(folder_id, rel);
                     self.log_activity(
                         ActivityKind::Trash,
@@ -797,7 +809,9 @@ impl Core {
         // Deferred folder deletions, deepest first.
         delete_local_dirs.sort_by_key(|p| std::cmp::Reverse(p.matches('/').count()));
         for rel in delete_local_dirs {
-            if let Err(e) = std::fs::remove_dir_all(local_root.join(rel_to_path(&rel))) {
+            if let Err(e) =
+                removed_locally(std::fs::remove_dir_all(local_root.join(rel_to_path(&rel))))
+            {
                 warn!(rel, error = %e, "sync: remove local folder failed");
                 self.log_activity(ActivityKind::Trash, base_name(&rel), e.to_string(), false);
                 outcome.errors += 1;
@@ -824,6 +838,9 @@ impl Core {
                 outcome.errors += 1;
                 continue;
             }
+            if let Some(parent) = parent_uid_of(&rel, &remote_dirs, &baseline) {
+                self.invalidate_children_of(&parent);
+            }
             let _ = self.db.sync_entry_remove(folder_id, &rel);
             self.log_activity(
                 ActivityKind::Trash,
@@ -849,68 +866,9 @@ impl Core {
         writing: &HashSet<PathBuf>,
         out: &mut HashMap<String, LocalItem>,
     ) -> Result<(), String> {
-        let entries = std::fs::read_dir(dir).map_err(|e| format!("read {}: {e}", dir.display()))?;
-        for entry in entries {
-            let entry = entry.map_err(|e| format!("read entry in {}: {e}", dir.display()))?;
-            let path = entry.path();
-            let meta = std::fs::symlink_metadata(&path)
-                .map_err(|e| format!("stat {}: {e}", path.display()))?;
-            let stripped = path.strip_prefix(root).map_err(|e| {
-                format!(
-                    "local path {} escaped sync root {}: {e}",
-                    path.display(),
-                    root.display()
-                )
-            })?;
-            let rel = stripped.to_str().ok_or_else(|| {
-                format!(
-                    "local path {} is not valid UTF-8; refusing a destructive sync pass",
-                    path.display()
-                )
-            })?;
-            // Ignore our own in-flight download temp files.
-            if rel.contains(".pdfs-tmp-") {
-                continue;
-            }
-            // Ignored paths are dropped here as well as from the classification
-            // union — not for correctness (the union filter is what makes this
-            // safe) but so an ignored `node_modules/` is never descended into or
-            // counted against scan progress.
-            if rules.is_ignored(rel, meta.is_dir()) {
-                continue;
-            }
-            if meta.is_dir() {
-                out.insert(
-                    rel.to_string(),
-                    LocalItem {
-                        is_dir: true,
-                        mtime: 0,
-                        size: 0,
-                        open_for_write: false,
-                    },
-                );
-                self.progress_scanned(folder_id, base_name(rel));
-                self.walk_local(folder_id, root, &path, rules, writing, out)?;
-            } else if meta.is_file() {
-                // Check whether any process holds this file open for writing.
-                // The canonical path is used because /proc/*/fd links resolve
-                // to canonical targets.
-                let ofw = std::fs::canonicalize(&path)
-                    .map(|canon| writing.contains(&canon))
-                    .unwrap_or(false);
-                out.insert(
-                    rel.to_string(),
-                    LocalItem {
-                        is_dir: false,
-                        mtime: system_mtime(&meta),
-                        size: meta.len() as i64,
-                        open_for_write: ofw,
-                    },
-                );
-                self.progress_scanned(folder_id, base_name(rel));
-            }
-        }
-        Ok(())
+        walk_local_tree(root, dir, rules, writing, out, &mut |rel| {
+            self.progress_scanned(folder_id, base_name(rel))
+        })
     }
 
     /// Map every remote folder under `folder` to its uid by rel path, ignoring
@@ -1069,6 +1027,7 @@ impl Core {
                     rel_path: rel.to_string(),
                     remote_uid: Some(uid.to_string()),
                     local_mtime: 0,
+                    local_mtime_ns: None,
                     local_size: 0,
                     remote_rev: None,
                     remote_hash: None,
@@ -1175,6 +1134,9 @@ impl Core {
                     .create_folder(parent, base_name(rel), Some(now_secs()))
                     .await
                     .map_err(|e| format!("create remote folder {rel}: {e}"))?;
+                // The parent has gained a child that no cached listing of it
+                // knows about (B86).
+                self.invalidate_children_of(parent);
                 self.baseline_dir(folder_id, rel, &uid)?;
                 Ok(Applied::Dir(rel.clone(), uid))
             }
@@ -1192,8 +1154,9 @@ impl Core {
                 uid,
                 mtime,
                 size,
+                local,
             } => {
-                self.download_file(folder_id, local_root, rel, uid, *mtime, *size)
+                self.download_file(folder_id, local_root, rel, uid, *mtime, *size, *local)
                     .await?;
                 Ok(Applied::Downloaded)
             }
@@ -1211,7 +1174,11 @@ impl Core {
                         .map_err(|e| format!("set aside conflict copy for {rel}: {e}"))?;
                     info!(rel, "sync: kept local changes as a conflict copy");
                 }
-                self.download_file(folder_id, local_root, rel, uid, *mtime, *size)
+                // The local copy has just been moved aside, so the state this
+                // download expects to find at the path is "nothing" — anything
+                // that appears while it runs is a *new* racing write, and gets
+                // its own conflict copy rather than being overwritten (B39).
+                self.download_file(folder_id, local_root, rel, uid, *mtime, *size, None)
                     .await?;
                 Ok(Applied::Conflict)
             }
@@ -1250,6 +1217,9 @@ impl Core {
         let file = std::fs::File::open(&path).map_err(|e| format!("open {rel}: {e}"))?;
         let meta = file.metadata().map_err(|e| format!("stat {rel}: {e}"))?;
         let mtime = system_mtime(&meta);
+        // Taken from the descriptor being streamed, so it names the content that
+        // actually goes up rather than whatever is at the path when we finish.
+        let streamed = LocalSig::from(&meta);
         // Count the bytes as they are read, so this upload shows up in
         // `GetQueueStatus` next to a manual one. The uid isn't known until the
         // draft is sealed, so the transfer registers without one.
@@ -1276,7 +1246,13 @@ impl Core {
             )
             .await
             .map_err(|e| format!("upload {rel}: {e}"))?;
-        self.record_file_baseline(folder_id, rel, &path, &uid).await
+        // The parent has gained a child that no cached listing of it knows
+        // about. Without this, a folder later switched to on-demand serves a
+        // snapshot that predates this upload (B86).
+        self.invalidate_children_of(parent);
+        warn_if_torn(rel, &path, streamed);
+        self.record_file_baseline(folder_id, rel, Some(streamed), &uid)
+            .await
     }
 
     /// Upload a changed local file as a new revision of an existing remote node.
@@ -1291,6 +1267,7 @@ impl Core {
         let file = std::fs::File::open(&path).map_err(|e| format!("open {rel}: {e}"))?;
         let meta = file.metadata().map_err(|e| format!("stat {rel}: {e}"))?;
         let mtime = system_mtime(&meta);
+        let streamed = LocalSig::from(&meta);
         let reader = OwnedCountingReader::new(
             file,
             self.transfers.begin(
@@ -1304,11 +1281,20 @@ impl Core {
             .upload_new_revision_from(uid, reader, meta.len() as i64, Vec::new(), Some(mtime))
             .await
             .map_err(|e| format!("upload revision {rel}: {e}"))?;
-        self.record_file_baseline(folder_id, rel, &path, uid).await
+        warn_if_torn(rel, &path, streamed);
+        self.record_file_baseline(folder_id, rel, Some(streamed), uid)
+            .await
     }
 
     /// Download a remote file to its local path (atomically via a temp file),
     /// stamp the local mtime to match the remote, then record baseline.
+    ///
+    /// `expected_local` is the identity planning saw at the destination. The
+    /// rename below is the destructive step, and the download in between can run
+    /// for minutes, so the destination is re-examined right before it: a local
+    /// file that no longer matches the plan is set aside as a conflict copy
+    /// instead of being replaced (bugs.md B39).
+    #[allow(clippy::too_many_arguments)]
     async fn download_file(
         &self,
         folder_id: i64,
@@ -1317,6 +1303,7 @@ impl Core {
         uid: &NodeUid,
         mtime: i64,
         size: i64,
+        expected_local: Option<LocalSig>,
     ) -> Result<(), String> {
         let path = local_root.join(rel_to_path(rel));
         if let Some(parent) = path.parent() {
@@ -1351,6 +1338,13 @@ impl Core {
             out.flush().map_err(|e| format!("flush tmp {rel}: {e}"))?;
             out.sync_all().map_err(|e| format!("sync tmp {rel}: {e}"))?;
         }
+        // The last moment at which the destination can still be saved. Anything
+        // other than the state planning classified means a writer got there
+        // first, and its bytes are the ones nothing else has a copy of.
+        if let Err(e) = keep_racing_local_edit(&path, expected_local) {
+            let _ = std::fs::remove_file(&tmp);
+            return Err(format!("set aside racing local edit for {rel}: {e}"));
+        }
         std::fs::rename(&tmp, &path).map_err(|e| format!("place {rel}: {e}"))?;
         // Match local mtime to the remote's so neither side looks "changed" next pass.
         let f = std::fs::File::options()
@@ -1366,23 +1360,36 @@ impl Core {
                 .and_then(|dir| dir.sync_all())
                 .map_err(|e| format!("sync directory for {rel}: {e}"))?;
         }
-        self.record_file_baseline(folder_id, rel, &path, uid).await
+        // Here the file on disk *is* the transferred content: it was published
+        // by a rename and stamped just above, so its stat is the identity.
+        self.record_file_baseline(folder_id, rel, local_sig(&path), uid)
+            .await
     }
 
-    /// Refresh a file's baseline from ground truth: the local stat and the
-    /// remote node's reported signature. Called after every upload/download so
-    /// the very next reconcile sees the path as unchanged.
+    /// Refresh a file's baseline from ground truth: the local identity these
+    /// bytes came from and the remote node's reported signature. Called after
+    /// every upload/download so the very next reconcile sees the path as
+    /// unchanged.
+    ///
+    /// `local` is the identity the *transferred content* corresponds to, which
+    /// is not always the file's current stat. An upload streams the live file,
+    /// so it passes the identity it read the first byte at: if a writer changed
+    /// the file mid-stream, the remote now holds a torn revision, and recording
+    /// the pre-upload identity is what makes the next pass see the path as
+    /// locally changed and upload a whole, clean revision over it. Recording the
+    /// post-upload stat instead declared the torn revision synchronized and left
+    /// it as the file's content on Drive (bugs.md B40).
     async fn record_file_baseline(
         &self,
         folder_id: i64,
         rel: &str,
-        local_path: &Path,
+        local: Option<LocalSig>,
         uid: &NodeUid,
     ) -> Result<(), String> {
-        let (lmtime, lsize) = match std::fs::metadata(local_path) {
-            Ok(m) => (system_mtime(&m), m.len() as i64),
-            Err(e) => return Err(format!("stat {rel}: {e}")),
+        let Some(local) = local else {
+            return Err(format!("stat {rel}: no local identity to baseline"));
         };
+        let (lmtime, lsize) = (local.mtime, local.size);
         // Re-fetch the node so the stored remote signature is exactly what a walk
         // will report next time.
         let (rmtime, rsize) = match self.client.enumerate_nodes(std::slice::from_ref(uid)).await {
@@ -1402,6 +1409,7 @@ impl Core {
                     rel_path: rel.to_string(),
                     remote_uid: Some(uid.to_string()),
                     local_mtime: lmtime,
+                    local_mtime_ns: local.mtime_ns,
                     local_size: lsize,
                     remote_rev: Some(rmtime.to_string()),
                     remote_hash: Some(rsize.to_string()),
@@ -1411,6 +1419,177 @@ impl Core {
     }
 }
 
+/// Say so when a file changed under an upload that was streaming it.
+///
+/// Purely diagnostic — the correction is already in place, because the baseline
+/// records the identity the upload *read* rather than the one on disk now, so
+/// the next pass classifies the path as locally changed and replaces the torn
+/// revision. Without the log there is nothing in the journal to explain the
+/// extra revision (bugs.md B40).
+fn warn_if_torn(rel: &str, path: &Path, streamed: LocalSig) {
+    let now = local_sig(path);
+    if !now.is_some_and(|now| now.same_content(&streamed)) {
+        warn!(
+            rel,
+            ?streamed,
+            ?now,
+            "sync: file changed while uploading; the remote revision may be torn \
+             and will be replaced on the next pass"
+        );
+    }
+}
+
+/// The identity a reconcile pass uses to recognise a local file it has already
+/// looked at: `None` when nothing is at the path.
+fn local_sig(path: &Path) -> Option<LocalSig> {
+    std::fs::metadata(path).ok().map(|m| LocalSig {
+        mtime: system_mtime(&m),
+        mtime_ns: system_mtime_ns(&m),
+        size: m.len() as i64,
+    })
+}
+
+/// Guard the destination of a download: if what is at `path` is no longer what
+/// planning classified, move it aside as a conflict copy before the caller
+/// renames over it.
+///
+/// A reconcile pass decides what to do from a walk that finished before the
+/// transfer started, and a download of a large file can run for minutes. Without
+/// this, a local edit completed inside that window was replaced by the remote
+/// version with no copy of it kept anywhere — the one shape of loss a sync
+/// engine must not have (bugs.md B39). Keeping the copy makes it re-upload as a
+/// new file on the next pass, which is the same resolution a both-sides-changed
+/// conflict already gets.
+///
+/// A path that is empty when it was expected to be is not a conflict: the
+/// download is about to recreate it, and there is nothing to preserve.
+fn keep_racing_local_edit(path: &Path, expected: Option<LocalSig>) -> std::io::Result<()> {
+    let actual = local_sig(path);
+    let unchanged = match (actual, expected) {
+        (Some(a), Some(e)) => a.same_content(&e),
+        // Nothing there: the download is about to create it, and there is
+        // nothing to preserve either way.
+        (None, _) => true,
+        (Some(_), None) => false,
+    };
+    if unchanged {
+        return Ok(());
+    }
+    warn!(
+        path = %path.display(),
+        ?expected,
+        ?actual,
+        "sync: local file changed while downloading; keeping it as a conflict copy"
+    );
+    preserve_conflict_copy(path, now_secs()).map(|_| ())
+}
+
+/// Read a local removal as the sync engine has to read it: the *state* it was
+/// asking for is "this path is gone", so a path that was already gone is a
+/// success, not a failure.
+///
+/// It matters because the baseline is only dropped on success. Treating
+/// `NotFound` as an error left the baseline in place for a file that no longer
+/// exists, so the same removal was re-attempted and re-reported as an error on
+/// every pass, forever. Every other error is still an error, and keeping the
+/// baseline is exactly right there: the surviving file must not be mistaken for
+/// a new local creation on the next pass and uploaded back (bugs.md B42).
+fn removed_locally(result: std::io::Result<()>) -> std::io::Result<()> {
+    match result {
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(()),
+        other => other,
+    }
+}
+
+/// The body of [`Core::walk_local`], without a `Core`: recursively collect the
+/// local tree under `dir` into `out`, reporting each entry to `scanned`.
+///
+/// **Every failure here is fatal to the pass, deliberately.** A `read_dir` that
+/// fails, an entry that cannot be stat-ed, a name that is not UTF-8 — each of
+/// them would, if skipped, leave `out` describing a *smaller* tree than the one
+/// on disk. Reconciliation reads a path present in the baseline and absent from
+/// the scan as "the user deleted this", and propagates that to Drive. So an
+/// unreadable subdirectory would trash its remote counterpart, and the deeper
+/// the failure, the more it takes with it (`docs/BUGS.md` B55). Refusing the
+/// whole pass keeps the previous baseline and leaves the remote alone; the next
+/// pass retries once the transient condition clears.
+///
+/// Split out from the method so exactly that can be tested against a real tree
+/// with a real unreadable directory in it, which needs no `Core` at all.
+fn walk_local_tree(
+    root: &Path,
+    dir: &Path,
+    rules: &IgnoreRules,
+    writing: &HashSet<PathBuf>,
+    out: &mut HashMap<String, LocalItem>,
+    scanned: &mut dyn FnMut(&str),
+) -> Result<(), String> {
+    let entries = std::fs::read_dir(dir).map_err(|e| format!("read {}: {e}", dir.display()))?;
+    for entry in entries {
+        let entry = entry.map_err(|e| format!("read entry in {}: {e}", dir.display()))?;
+        let path = entry.path();
+        let meta = std::fs::symlink_metadata(&path)
+            .map_err(|e| format!("stat {}: {e}", path.display()))?;
+        let stripped = path.strip_prefix(root).map_err(|e| {
+            format!(
+                "local path {} escaped sync root {}: {e}",
+                path.display(),
+                root.display()
+            )
+        })?;
+        let rel = stripped.to_str().ok_or_else(|| {
+            format!(
+                "local path {} is not valid UTF-8; refusing a destructive sync pass",
+                path.display()
+            )
+        })?;
+        // Ignore our own in-flight download temp files.
+        if rel.contains(".pdfs-tmp-") {
+            continue;
+        }
+        // Ignored paths are dropped here as well as from the classification
+        // union — not for correctness (the union filter is what makes this
+        // safe) but so an ignored `node_modules/` is never descended into or
+        // counted against scan progress.
+        if rules.is_ignored(rel, meta.is_dir()) {
+            continue;
+        }
+        if meta.is_dir() {
+            out.insert(
+                rel.to_string(),
+                LocalItem {
+                    is_dir: true,
+                    mtime: 0,
+                    mtime_ns: None,
+                    size: 0,
+                    open_for_write: false,
+                },
+            );
+            scanned(rel);
+            walk_local_tree(root, &path, rules, writing, out, scanned)?;
+        } else if meta.is_file() {
+            // Check whether any process holds this file open for writing.
+            // The canonical path is used because /proc/*/fd links resolve
+            // to canonical targets.
+            let ofw = std::fs::canonicalize(&path)
+                .map(|canon| writing.contains(&canon))
+                .unwrap_or(false);
+            out.insert(
+                rel.to_string(),
+                LocalItem {
+                    is_dir: false,
+                    mtime: system_mtime(&meta),
+                    mtime_ns: system_mtime_ns(&meta),
+                    size: meta.len() as i64,
+                    open_for_write: ofw,
+                },
+            );
+            scanned(rel);
+        }
+    }
+    Ok(())
+}
+
 /// Publish a conflict copy without overwriting an earlier conflict bearing the
 /// same timestamp. The original is removed only after the new copy is durable.
 fn preserve_conflict_copy(path: &Path, stamp: i64) -> std::io::Result<PathBuf> {
@@ -1444,6 +1623,26 @@ fn preserve_conflict_copy(path: &Path, stamp: i64) -> std::io::Result<PathBuf> {
     unreachable!("u32 conflict suffix space exhausted")
 }
 
+/// The remote uid of `rel`'s parent folder: from the pass's folder-uid map
+/// first, and from the baseline second for a parent the map never covered.
+///
+/// Used to name the folder whose cached listing a remote mutation has just
+/// invalidated (B86). `None` is not an error — it only means this pass cannot
+/// say which folder to invalidate, and the caller skips it.
+fn parent_uid_of(
+    rel: &str,
+    remote_dirs: &HashMap<String, NodeUid>,
+    baseline: &HashMap<String, StoredSyncEntry>,
+) -> Option<NodeUid> {
+    let parent = parent_rel(rel);
+    remote_dirs.get(parent).cloned().or_else(|| {
+        baseline
+            .get(parent)
+            .and_then(|e| e.remote_uid.as_deref())
+            .and_then(parse_uid)
+    })
+}
+
 fn sync_parent_dir(path: &Path) -> std::io::Result<()> {
     match path.parent() {
         Some(parent) => std::fs::File::open(parent)?.sync_all(),
@@ -1476,10 +1675,77 @@ fn system_mtime(meta: &std::fs::Metadata) -> i64 {
         .map(|d| d.as_secs() as i64)
         .unwrap_or(0)
 }
+
+/// The same modification time in nanoseconds, when the filesystem reports one.
+///
+/// Whole seconds cannot distinguish an edit made in the same second as the last
+/// sync from no edit at all, and if the size did not change either, that file
+/// was never uploaded (bugs.md B25). `None` for a clock or filesystem that
+/// cannot answer, which falls the comparison back to seconds rather than
+/// asserting an mtime of zero.
+fn system_mtime_ns(meta: &std::fs::Metadata) -> Option<i64> {
+    meta.modified()
+        .ok()
+        .and_then(|t| t.duration_since(SystemTime::UNIX_EPOCH).ok())
+        .and_then(|d| i64::try_from(d.as_nanos()).ok())
+}
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    /// A removal of something already gone has produced the state the sync
+    /// engine wanted, so its baseline is dropped rather than retried forever.
+    /// Anything else stays an error and keeps the baseline (bugs.md B42).
+    #[test]
+    fn an_already_absent_path_counts_as_removed() {
+        let root = std::env::temp_dir().join(format!("pdfs-b42-{}", std::process::id()));
+        let missing = root.join("never-existed");
+        assert!(removed_locally(std::fs::remove_file(&missing)).is_ok());
+        assert!(removed_locally(std::fs::remove_dir_all(&missing)).is_ok());
+
+        // A directory in the way of `remove_file` is a real failure, and must
+        // stay one: the file survives, and its baseline has to survive with it.
+        let occupied = root.join("a-directory");
+        std::fs::create_dir_all(&occupied).unwrap();
+        assert!(removed_locally(std::fs::remove_file(&occupied)).is_err());
+        let _ = std::fs::remove_dir_all(&root);
+    }
+
+    /// The download guard: a destination that still matches the plan is
+    /// replaced silently, one that has moved on since is kept (bugs.md B39).
+    #[test]
+    fn a_download_keeps_a_local_edit_it_did_not_plan_for() {
+        let root = std::env::temp_dir().join(format!("pdfs-b39-{}", std::process::id()));
+        std::fs::create_dir_all(&root).unwrap();
+        let path = root.join("report.txt");
+
+        // Nothing there, nothing expected: the download simply creates it.
+        assert!(keep_racing_local_edit(&path, None).is_ok());
+        assert!(!path.exists());
+
+        // Unchanged since planning: no copy, the caller overwrites it.
+        std::fs::write(&path, b"planned").unwrap();
+        let planned = local_sig(&path).unwrap();
+        keep_racing_local_edit(&path, Some(planned)).unwrap();
+        assert_eq!(std::fs::read(&path).unwrap(), b"planned");
+
+        // Changed since planning: the racing bytes are the only copy of
+        // themselves, so they must survive the overwrite as a conflict copy.
+        std::fs::write(&path, b"a much longer local edit").unwrap();
+        keep_racing_local_edit(&path, Some(planned)).unwrap();
+        let kept: Vec<_> = std::fs::read_dir(&root)
+            .unwrap()
+            .filter_map(|e| e.ok())
+            .map(|e| std::fs::read(e.path()).unwrap_or_default())
+            .collect();
+        assert!(
+            kept.iter()
+                .any(|bytes| bytes == b"a much longer local edit"),
+            "the racing edit must still exist somewhere: {kept:?}"
+        );
+        let _ = std::fs::remove_dir_all(&root);
+    }
+
     /// Feed `n` `Reconcile` events `gap` apart on another thread, starting
     /// immediately. Returns the sender's join handle so the test can keep it
     /// alive (dropping the sender early would look like a disconnect).
@@ -1565,6 +1831,7 @@ mod tests {
 
     fn local_item(is_dir: bool) -> LocalItem {
         LocalItem {
+            mtime_ns: None,
             is_dir,
             mtime: 1,
             size: 1,
@@ -1722,6 +1989,44 @@ mod tests {
         assert!(guard_local_wipe(&base, &fresh).is_err());
     }
 
+    /// B54's remaining case, end to end: a folder whose local root is still
+    /// *readable* but is no longer the tree it was — an empty directory left
+    /// where a mount used to be, or a different device mounted over it.
+    ///
+    /// Nothing fails here. The scan succeeds and honestly reports an empty
+    /// directory, so the only thing standing between the user and a trashed
+    /// remote folder is the guard, and it has to fire for a one-file baseline
+    /// exactly as it does for a large one.
+    #[test]
+    fn a_replaced_mountpoint_trips_the_guard_at_every_baseline_size() {
+        let root = sync_test_dir("wipe-replaced-mount");
+        let rules = rules_for(&[]);
+        let writing = HashSet::new();
+        let mut local: HashMap<String, LocalItem> = HashMap::new();
+        let mut progress = no_progress();
+        walk_local_tree(&root, &root, &rules, &writing, &mut local, &mut progress).unwrap();
+        assert!(local.is_empty(), "the replacement root is genuinely empty");
+
+        for size in 1..=3 {
+            let baseline: HashMap<String, ()> =
+                (0..size).map(|i| (format!("file{i}.txt"), ())).collect();
+            assert!(
+                guard_local_wipe(&filter_baseline(&baseline, &rules), &local).is_err(),
+                "a {size}-path baseline against an empty root is not a deletion"
+            );
+        }
+
+        // And the guard steps aside the moment the real tree is back, so a
+        // remounted folder resumes rather than staying wedged.
+        std::fs::write(root.join("file0.txt"), b"back").unwrap();
+        let mut local: HashMap<String, LocalItem> = HashMap::new();
+        walk_local_tree(&root, &root, &rules, &writing, &mut local, &mut progress).unwrap();
+        let baseline: HashMap<String, ()> = [("file0.txt".to_string(), ())].into_iter().collect();
+        assert!(guard_local_wipe(&filter_baseline(&baseline, &rules), &local).is_ok());
+
+        std::fs::remove_dir_all(&root).unwrap();
+    }
+
     /// A restored folder (features.md 5.2) starts with an empty baseline against
     /// an empty local directory and a full remote. That must reconcile as
     /// "download everything" rather than tripping the wipe guard — otherwise
@@ -1764,6 +2069,7 @@ mod tests {
                 remote_uid: Some("v~l".into()),
                 local_mtime: 0,
                 local_size: 0,
+                local_mtime_ns: None,
                 remote_rev: Some(mtime.to_string()),
                 remote_hash: Some(size.to_string()),
             },
@@ -1801,6 +2107,7 @@ mod tests {
                 remote_uid: Some("v~l".into()),
                 local_mtime: 0,
                 local_size: 0,
+                local_mtime_ns: None,
                 remote_rev: None,
                 remote_hash: None,
             },
@@ -1815,6 +2122,7 @@ mod tests {
             remote_uid: Some("v~l".into()),
             local_mtime: 10,
             local_size: 20,
+            local_mtime_ns: None,
             remote_rev: Some("1700".into()),
             remote_hash: Some("4096".into()),
         };
@@ -1828,6 +2136,7 @@ mod tests {
             remote_uid: Some("v~l".into()),
             local_mtime: 0,
             local_size: 0,
+            local_mtime_ns: None,
             remote_rev: None,
             remote_hash: None,
         };
@@ -1863,6 +2172,7 @@ mod tests {
             uid: uid(),
             mtime: 0,
             size: 10,
+            local: None,
         };
         assert_eq!(op.kind(), ActivityKind::Download);
     }
@@ -1918,6 +2228,204 @@ mod tests {
         std::fs::remove_dir_all(dir).unwrap();
     }
 
+    /// B49's remaining cases. Preservation is the step that makes a download
+    /// safe to publish, so every way it can fail has to leave the local file
+    /// where it was — the download is aborted, not the file replaced.
+    #[test]
+    fn conflict_preservation_failures_all_keep_the_local_file() {
+        use std::os::unix::fs::PermissionsExt as _;
+
+        // An unwritable directory: the conflict copy cannot be created at all.
+        let dir = sync_test_dir("conflict-eacces");
+        let source = dir.join("notes.txt");
+        std::fs::write(&source, b"the only copy").unwrap();
+        std::fs::set_permissions(&dir, std::fs::Permissions::from_mode(0o500)).unwrap();
+        let denied = preserve_conflict_copy(&source, 1700);
+        std::fs::set_permissions(&dir, std::fs::Permissions::from_mode(0o700)).unwrap();
+        assert!(denied.is_err(), "a read-only directory must fail the copy");
+        assert_eq!(
+            std::fs::read(&source).unwrap(),
+            b"the only copy",
+            "the local file survives byte-identical"
+        );
+        std::fs::remove_dir_all(&dir).unwrap();
+
+        // A source that vanished between planning and preservation. The pass
+        // must report it rather than publish the download over the gap.
+        let dir = sync_test_dir("conflict-enoent");
+        assert!(preserve_conflict_copy(&dir.join("gone.txt"), 1700).is_err());
+        std::fs::remove_dir_all(&dir).unwrap();
+
+        // A write error partway through the copy — induced by making the
+        // destination name a directory, so `create_new` fails as something
+        // other than `AlreadyExists`.
+        let dir = sync_test_dir("conflict-eisdir");
+        let source = dir.join("notes.txt");
+        std::fs::write(&source, b"still the only copy").unwrap();
+        std::fs::create_dir(conflict_path(&source, 1700)).unwrap();
+        // Suffix 0 is taken by a directory; `create_new` on it reports
+        // `AlreadyExists`, so preservation moves on to suffix 1 and succeeds.
+        // What must not happen is the source being removed without a copy.
+        let preserved = preserve_conflict_copy(&source, 1700).unwrap();
+        assert!(preserved.is_file());
+        assert_eq!(std::fs::read(&preserved).unwrap(), b"still the only copy");
+        assert!(!source.exists());
+        std::fs::remove_dir_all(&dir).unwrap();
+    }
+
+    /// A conflict copy keeps the bytes *and* the metadata that identifies them,
+    /// so the next pass uploads the user's version rather than a file that looks
+    /// freshly written.
+    #[test]
+    fn a_conflict_copy_is_byte_and_mtime_identical() {
+        use std::os::unix::fs::PermissionsExt as _;
+
+        let dir = sync_test_dir("conflict-identity");
+        let source = dir.join("notes.txt");
+        std::fs::write(&source, b"local edit that must survive").unwrap();
+        let before = std::fs::metadata(&source).unwrap();
+
+        let preserved = preserve_conflict_copy(&source, 1700).unwrap();
+        let after = std::fs::metadata(&preserved).unwrap();
+
+        assert_eq!(
+            std::fs::read(&preserved).unwrap(),
+            b"local edit that must survive"
+        );
+        assert_eq!(after.len(), before.len());
+        assert_eq!(after.modified().unwrap(), before.modified().unwrap());
+        assert_eq!(after.permissions().mode(), before.permissions().mode());
+        std::fs::remove_dir_all(&dir).unwrap();
+    }
+
+    // ---- B55: an incomplete local scan is never a set of deletions ---------
+
+    fn no_progress() -> impl FnMut(&str) {
+        |_: &str| {}
+    }
+
+    /// A directory the pass cannot read must fail the pass. Omitting it would
+    /// hand reconciliation a baseline-minus-subtree, which it reads as the user
+    /// having deleted that subtree and propagates to Drive (B55).
+    #[test]
+    fn an_unreadable_subdirectory_fails_the_scan_instead_of_shrinking_it() {
+        use std::os::unix::fs::PermissionsExt as _;
+
+        let root = sync_test_dir("scan-eacces");
+        std::fs::write(root.join("keep.txt"), b"a").unwrap();
+        let locked = root.join("locked");
+        std::fs::create_dir(&locked).unwrap();
+        std::fs::write(locked.join("inner.txt"), b"b").unwrap();
+        std::fs::set_permissions(&locked, std::fs::Permissions::from_mode(0o000)).unwrap();
+
+        let rules = rules_for(&[]);
+        let writing = HashSet::new();
+        let mut out = HashMap::new();
+        let mut progress = no_progress();
+        let result = walk_local_tree(&root, &root, &rules, &writing, &mut out, &mut progress);
+
+        std::fs::set_permissions(&locked, std::fs::Permissions::from_mode(0o700)).unwrap();
+        std::fs::remove_dir_all(&root).unwrap();
+
+        let error = result.expect_err("an unreadable directory must abort the pass");
+        assert!(
+            error.contains("locked"),
+            "the error should name the subtree it could not read: {error}"
+        );
+    }
+
+    /// The same rule one level up: if the sync root itself cannot be read, the
+    /// pass sees nothing, and "nothing" must never mean "delete everything".
+    #[test]
+    fn an_unreadable_root_fails_the_scan() {
+        use std::os::unix::fs::PermissionsExt as _;
+
+        let root = sync_test_dir("scan-root-eacces");
+        std::fs::write(root.join("keep.txt"), b"a").unwrap();
+        std::fs::set_permissions(&root, std::fs::Permissions::from_mode(0o000)).unwrap();
+
+        let rules = rules_for(&[]);
+        let writing = HashSet::new();
+        let mut out = HashMap::new();
+        let mut progress = no_progress();
+        let result = walk_local_tree(&root, &root, &rules, &writing, &mut out, &mut progress);
+
+        std::fs::set_permissions(&root, std::fs::Permissions::from_mode(0o700)).unwrap();
+        std::fs::remove_dir_all(&root).unwrap();
+
+        assert!(result.is_err());
+        assert!(out.is_empty());
+    }
+
+    /// A root that is gone entirely — an unmounted device folder, a removed
+    /// directory — is the sharpest version of the same case: every baseline path
+    /// is "missing", and the scan must refuse rather than report an empty tree.
+    #[test]
+    fn an_absent_root_fails_the_scan() {
+        let root = sync_test_dir("scan-absent");
+        std::fs::remove_dir_all(&root).unwrap();
+
+        let rules = rules_for(&[]);
+        let writing = HashSet::new();
+        let mut out = HashMap::new();
+        let mut progress = no_progress();
+        assert!(walk_local_tree(&root, &root, &rules, &writing, &mut out, &mut progress).is_err());
+        assert!(out.is_empty());
+    }
+
+    /// A name that is not valid UTF-8 cannot be keyed into the scan, so it
+    /// cannot be compared against the baseline either. Refusing the pass is the
+    /// only safe reading: skipping it would classify the file as deleted.
+    #[test]
+    fn a_non_utf8_name_fails_the_scan() {
+        use std::ffi::OsStr;
+        use std::os::unix::ffi::OsStrExt as _;
+
+        let root = sync_test_dir("scan-non-utf8");
+        std::fs::write(root.join(OsStr::from_bytes(b"bad\xffname")), b"x").unwrap();
+
+        let rules = rules_for(&[]);
+        let writing = HashSet::new();
+        let mut out = HashMap::new();
+        let mut progress = no_progress();
+        let result = walk_local_tree(&root, &root, &rules, &writing, &mut out, &mut progress);
+        std::fs::remove_dir_all(&root).unwrap();
+
+        let error = result.expect_err("a name the scan cannot key must abort the pass");
+        assert!(error.contains("UTF-8"), "{error}");
+    }
+
+    /// The complement: a scan that *can* read everything reports everything, so
+    /// the strictness above does not come at the cost of a working pass. A
+    /// symlink is skipped by design rather than by failure, and a dangling one
+    /// stats fine through `symlink_metadata`.
+    #[test]
+    fn a_readable_tree_scans_completely() {
+        let root = sync_test_dir("scan-complete");
+        std::fs::write(root.join("a.txt"), b"aa").unwrap();
+        std::fs::create_dir(root.join("sub")).unwrap();
+        std::fs::write(root.join("sub/b.txt"), b"bbb").unwrap();
+        std::os::unix::fs::symlink("nowhere", root.join("dangling")).unwrap();
+
+        let rules = rules_for(&[]);
+        let writing = HashSet::new();
+        let mut out = HashMap::new();
+        let mut seen: Vec<String> = Vec::new();
+        let result = walk_local_tree(&root, &root, &rules, &writing, &mut out, &mut |rel| {
+            seen.push(rel.to_string())
+        });
+        std::fs::remove_dir_all(&root).unwrap();
+
+        result.unwrap();
+        let mut keys: Vec<&str> = out.keys().map(String::as_str).collect();
+        keys.sort_unstable();
+        assert_eq!(keys, vec!["a.txt", "sub", "sub/b.txt"]);
+        assert_eq!(out["a.txt"].size, 2);
+        assert_eq!(out["sub/b.txt"].size, 3);
+        assert!(out["sub"].is_dir);
+        assert_eq!(seen.len(), 3, "every reported entry ticks scan progress");
+    }
+
     fn sync_test_dir(label: &str) -> PathBuf {
         let nonce = SystemTime::now()
             .duration_since(SystemTime::UNIX_EPOCH)

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

@@ -32,17 +32,24 @@ pub(crate) enum SyncMsg {
     ReconcileAll,
     /// 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).
+    Stop,
 }
 
 /// Start the sync engine: a control thread that owns the filesystem watcher and
 /// serialises reconcile passes, plus a periodic poll thread. The engine receives
 /// on `rx`; senders live in [`Core::sync_tx`].
-pub(crate) fn spawn(core: Core, rx: Receiver<SyncMsg>) {
-    if let Err(e) = std::thread::Builder::new()
+pub(crate) fn spawn(core: Core, rx: Receiver<SyncMsg>) -> Option<std::thread::JoinHandle<()>> {
+    match std::thread::Builder::new()
         .name("pdfs-sync".into())
         .spawn(move || engine_loop(core, rx))
     {
-        warn!(error = %e, "failed to start sync engine");
+        Ok(handle) => Some(handle),
+        Err(e) => {
+            warn!(error = %e, "failed to start sync engine");
+            None
+        }
     }
 }
 
@@ -74,11 +81,11 @@ fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
     // Periodic remote poll.
     {
         let tx = core.sync_tx.clone();
+        let shutdown = core.shutdown.clone();
         std::thread::Builder::new()
             .name("pdfs-sync-poll".into())
             .spawn(move || {
-                loop {
-                    std::thread::sleep(POLL_INTERVAL);
+                while shutdown.sleep(POLL_INTERVAL) {
                     if tx.send(SyncMsg::ReconcileAll).is_err() {
                         break;
                     }
@@ -94,8 +101,12 @@ fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
         let mut ids: HashSet<i64> = HashSet::new();
         let mut all = false;
         let mut do_rewatch = false;
-        classify(msg, &mut ids, &mut all, &mut do_rewatch);
-        settle(&rx, &mut ids, &mut all, &mut do_rewatch);
+        if !classify(msg, &mut ids, &mut all, &mut do_rewatch)
+            || !settle(&rx, &mut ids, &mut all, &mut do_rewatch)
+        {
+            info!("sync engine stopping");
+            return;
+        }
 
         if do_rewatch {
             rewatch(&core, &mut watcher, &watched);
@@ -116,9 +127,9 @@ fn engine_loop(core: Core, rx: Receiver<SyncMsg>) {
 fn poll_only_loop(core: &Core, rx: Receiver<SyncMsg>) {
     {
         let tx = core.sync_tx.clone();
+        let shutdown = core.shutdown.clone();
         std::thread::spawn(move || {
-            loop {
-                std::thread::sleep(POLL_INTERVAL);
+            while shutdown.sleep(POLL_INTERVAL) {
                 if tx.send(SyncMsg::ReconcileAll).is_err() {
                     break;
                 }
@@ -130,8 +141,12 @@ fn poll_only_loop(core: &Core, rx: Receiver<SyncMsg>) {
         let mut ids: HashSet<i64> = HashSet::new();
         let mut all = false;
         let mut do_rewatch = false;
-        classify(msg, &mut ids, &mut all, &mut do_rewatch);
-        settle(&rx, &mut ids, &mut all, &mut do_rewatch);
+        if !classify(msg, &mut ids, &mut all, &mut do_rewatch)
+            || !settle(&rx, &mut ids, &mut all, &mut do_rewatch)
+        {
+            info!("sync engine stopping");
+            return;
+        }
         if all {
             reconcile_all(core);
         } else {
@@ -158,7 +173,7 @@ pub(super) fn settle_with(
     do_rewatch: &mut bool,
     quiet: Duration,
     cap: Duration,
-) {
+) -> bool {
     let deadline = Instant::now() + cap;
     loop {
         let now = Instant::now();
@@ -170,28 +185,49 @@ pub(super) fn settle_with(
         match rx.recv_timeout(wait) {
             // Another event: the burst is still going, so the quiet window
             // starts again from here.
-            Ok(m) => classify(m, ids, all, do_rewatch),
+            // A stop lands mid-burst: give up the rest of the burst rather
+            // than settling for it, and let the caller end the loop.
+            Ok(m) => {
+                if !classify(m, ids, all, do_rewatch) {
+                    return false;
+                }
+            }
             // Quiet for a full window: whatever was being written has stopped.
             Err(RecvTimeoutError::Timeout) => break,
             // Every sender is gone; the caller's loop is about to end anyway.
             Err(RecvTimeoutError::Disconnected) => break,
         }
     }
+    true
 }
 
 /// [`settle_with`] at the real timings.
-fn settle(rx: &Receiver<SyncMsg>, ids: &mut HashSet<i64>, all: &mut bool, do_rewatch: &mut bool) {
-    settle_with(rx, ids, all, do_rewatch, DEBOUNCE, MAX_SETTLE);
+fn settle(
+    rx: &Receiver<SyncMsg>,
+    ids: &mut HashSet<i64>,
+    all: &mut bool,
+    do_rewatch: &mut bool,
+) -> bool {
+    settle_with(rx, ids, all, do_rewatch, DEBOUNCE, MAX_SETTLE)
 }
 
-pub(super) fn classify(msg: SyncMsg, ids: &mut HashSet<i64>, all: &mut bool, rewatch: &mut bool) {
+/// Fold one message into the pending work of the current burst. Returns `false`
+/// for [`SyncMsg::Stop`], which is not work but an instruction to end the loop.
+pub(super) fn classify(
+    msg: SyncMsg,
+    ids: &mut HashSet<i64>,
+    all: &mut bool,
+    rewatch: &mut bool,
+) -> bool {
     match msg {
         SyncMsg::Reconcile(id) => {
             ids.insert(id);
         }
         SyncMsg::ReconcileAll => *all = true,
         SyncMsg::Rewatch => *rewatch = true,
+        SyncMsg::Stop => return false,
     }
+    true
 }
 
 /// Reconcile every mirror folder in turn.

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

@@ -2,9 +2,73 @@
 
 use super::*;
 
+/// What a reconcile pass remembers about the local side of one path: enough to
+/// recognise the same content again, and no more.
+///
+/// `mtime_ns` is the whole reason this is a struct rather than a pair — see
+/// [`StoredSyncEntry::local_mtime_ns`](pdfs_core::db::StoredSyncEntry).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub(super) struct LocalSig {
+    pub(super) mtime: i64,
+    pub(super) mtime_ns: Option<i64>,
+    pub(super) size: i64,
+}
+
+impl LocalSig {
+    /// Whether these two observations describe the same local content.
+    ///
+    /// 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).
+    pub(super) fn same_content(&self, other: &Self) -> bool {
+        if self.size != other.size {
+            return false;
+        }
+        match (self.mtime_ns, other.mtime_ns) {
+            (Some(a), Some(b)) => a == b,
+            _ => self.mtime == other.mtime,
+        }
+    }
+}
+
+impl From<&LocalItem> for LocalSig {
+    fn from(item: &LocalItem) -> Self {
+        Self {
+            mtime: item.mtime,
+            mtime_ns: item.mtime_ns,
+            size: item.size,
+        }
+    }
+}
+
+impl From<&std::fs::Metadata> for LocalSig {
+    fn from(meta: &std::fs::Metadata) -> Self {
+        Self {
+            mtime: system_mtime(meta),
+            mtime_ns: system_mtime_ns(meta),
+            size: meta.len() as i64,
+        }
+    }
+}
+
+/// The baseline's record of the local side, as [`LocalSig`] compares it.
+impl From<&StoredSyncEntry> for LocalSig {
+    fn from(entry: &StoredSyncEntry) -> Self {
+        Self {
+            mtime: entry.local_mtime,
+            mtime_ns: entry.local_mtime_ns,
+            size: entry.local_size,
+        }
+    }
+}
+
 pub(super) struct LocalItem {
     pub(super) is_dir: bool,
     pub(super) mtime: i64,
+    /// [`LocalItem::mtime`] to nanosecond precision, when the filesystem
+    /// reports one.
+    pub(super) mtime_ns: Option<i64>,
     pub(super) size: i64,
     /// True when another process holds this file open for writing (detected via
     /// `/proc/*/fd`). An open-for-write file is kept in the map — so it is not
@@ -91,11 +155,18 @@ pub(super) enum Pending {
     UploadRevision { rel: String, uid: NodeUid },
     /// Download remote `uid` to the local path, stamping `mtime`. `size` is the
     /// remote's reported size, used as the transfer's expected total.
+    ///
+    /// `local` is what the planning walk saw at this path, or `None` if nothing
+    /// was there. A download can run for minutes, so the apply step revalidates
+    /// 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).
     Download {
         rel: String,
         uid: NodeUid,
         mtime: i64,
         size: i64,
+        local: Option<LocalSig>,
     },
     /// Both sides changed: set the local copy aside, then download remote `uid`.
     Conflict {

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

@@ -218,7 +218,10 @@ pub(super) fn plan_file(
     }
 
     let local_changed = local.is_some_and(|item| {
-        baseline.is_none_or(|base| base.local_mtime != item.mtime || base.local_size != item.size)
+        // Nanoseconds where both sides have them (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)))
     });
     let remote_changed = remote.is_some_and(|item| {
         baseline.is_none_or(|base| remote_sig(base) != Some((item.mtime, item.size)))
@@ -252,6 +255,7 @@ mod file_plan_tests {
 
     fn local(mtime: i64, size: i64) -> LocalItem {
         LocalItem {
+            mtime_ns: None,
             is_dir: false,
             mtime,
             size,
@@ -278,12 +282,49 @@ mod file_plan_tests {
             rel_path: "file".into(),
             remote_uid: Some("v~l".into()),
             local_mtime,
+            local_mtime_ns: None,
             local_size,
             remote_rev: Some(remote_mtime.to_string()),
             remote_hash: Some(remote_size.to_string()),
         }
     }
 
+    /// 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).
+    #[test]
+    fn a_same_second_same_size_edit_is_still_a_local_change() {
+        let mut base = baseline(10, 20, 30, 40);
+        base.local_mtime_ns = Some(10_000_000_000);
+        let edited = LocalItem {
+            mtime_ns: Some(10_400_000_000),
+            ..local(10, 20)
+        };
+        let remote = remote(30, 40);
+        assert_eq!(
+            plan_file(Some(&edited), Some(&remote), Some(&base)),
+            FilePlan::UploadRevision
+        );
+
+        // The same file untouched still reads as unchanged.
+        let same = LocalItem {
+            mtime_ns: Some(10_000_000_000),
+            ..local(10, 20)
+        };
+        assert_eq!(
+            plan_file(Some(&same), Some(&remote), Some(&base)),
+            FilePlan::Unchanged
+        );
+
+        // And a row from before the column exists compares on seconds, exactly
+        // as it did when it was written — no mass re-upload on upgrade.
+        let old = baseline(10, 20, 30, 40);
+        assert_eq!(
+            plan_file(Some(&edited), Some(&remote), Some(&old)),
+            FilePlan::Unchanged
+        );
+    }
+
     #[test]
     fn file_plan_covers_every_presence_and_change_shape() {
         let same_local = local(10, 20);

crates/pdfs-fuse/src/takeout.rs

@@ -0,0 +1,632 @@
+//! Importing a Google Photos Takeout export into Proton Photos.
+//!
+//! [`pdfs_core::takeout`] says what is in the archives; this is the part that
+//! talks to Proton. One import runs on its own thread and moves through four
+//! phases, reporting into the transfer registry as a job so the GUI's transfer
+//! list shows it without a bespoke widget:
+//!
+//! 1. **Scan** — read the archives' central directories and sidecars.
+//! 2. **Deduplicate against the account** — ask the photos volume which of the
+//!    names already exist ([`ProtonPhotosClient::name_collisions`]), hash only
+//!    those files, then confirm with the content digest. A library that is
+//!    already half-synced by Proton Photos on a phone therefore costs one cheap
+//!    request per 150 names and reads no media at all for the misses.
+//! 3. **Upload** the survivors, streaming each entry straight out of its zip —
+//!    no extraction to disk, so the import needs no scratch space.
+//! 4. **Albums** — create the albums the export names that the account lacks,
+//!    then add every photo of each album, the ones that were already on the
+//!    account included.
+//!
+//! Re-running an interrupted import is the resume story: phase 2 finds
+//! everything the previous run uploaded and skips it. Nothing is persisted
+//! between runs.
+
+use std::collections::{BTreeMap, HashMap};
+use std::io::Read;
+use std::path::PathBuf;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+
+use pdfs_core::control::{ActivityKind, ImportSummary, TransferDirection};
+use pdfs_core::takeout::{Bucket, TakeoutPhoto, TakeoutScan, scan_archives};
+use pdfs_core::{CoreError, CoreResult};
+use proton_drive_rs::proton_sdk::ids::NodeUid;
+use proton_drive_rs::{PhotoTag, PhotoTagsUpdate, PhotoUploadMetadata};
+use sha1::{Digest, Sha1};
+use tracing::{info, warn};
+
+use super::Core;
+use crate::transfers::CountingReader;
+
+/// The one import this daemon may be running, and how the last one ended.
+///
+/// Process-global rather than a [`Core`] field because it must be *one* import
+/// per daemon however many `Core` clones exist (the forked on-demand mounts each
+/// hold one), and because a front-end asking for the result after the import
+/// finished must still find it.
+static IMPORT: std::sync::LazyLock<parking_lot::Mutex<ImportState>> =
+    std::sync::LazyLock::new(|| parking_lot::Mutex::new(ImportState::default()));
+
+#[derive(Default)]
+struct ImportState {
+    running: bool,
+    cancel: Option<Arc<AtomicBool>>,
+    last: Option<ImportSummary>,
+}
+
+/// Whether an import is running, and the last one's report.
+pub(crate) fn import_status() -> (bool, Option<ImportSummary>) {
+    let state = IMPORT.lock();
+    (state.running, state.last.clone())
+}
+
+/// Ask the running import to stop. False when none is running.
+pub(crate) fn cancel_import() -> bool {
+    match &IMPORT.lock().cancel {
+        Some(flag) => {
+            flag.store(true, Ordering::Relaxed);
+            true
+        }
+        None => false,
+    }
+}
+
+/// One photo to import, after the copies Google keeps per album are folded into
+/// a single upload that joins several albums.
+struct Planned {
+    photo: TakeoutPhoto,
+    /// Every album this photo belongs to, by export title.
+    albums: Vec<String>,
+    /// Filled in phase 2/3: where the photo ended up on the account.
+    uid: Option<NodeUid>,
+}
+
+/// Fold the scan into one entry per distinct photo.
+///
+/// Google stores a full copy of a photo in every album folder it appears in, so
+/// the same file is in the export two or three times over. They are folded on
+/// `(name, size)`: a byte-identical copy under the same name is the same photo,
+/// and the album memberships of the copies are unioned onto the survivor. Two
+/// genuinely different photos sharing both a name and an exact size would be
+/// merged — vanishingly unlikely, and the cost of being wrong is one photo
+/// filed under an extra album rather than lost data.
+fn plan(scan: &TakeoutScan) -> Vec<Planned> {
+    let mut order: Vec<(String, u64)> = Vec::new();
+    let mut by_key: HashMap<(String, u64), Planned> = HashMap::new();
+
+    for photo in &scan.photos {
+        let key = (photo.name.clone(), photo.size);
+        let entry = by_key.entry(key.clone()).or_insert_with(|| {
+            order.push(key.clone());
+            Planned {
+                photo: photo.clone(),
+                albums: Vec::new(),
+                uid: None,
+            }
+        });
+        if let Bucket::Album(title) = &photo.bucket
+            && !entry.albums.iter().any(|existing| existing == title)
+        {
+            entry.albums.push(title.clone());
+        }
+        // A copy that carries a capture time wins over one that does not: the
+        // album copy and the year-folder copy do not always both have a sidecar.
+        if entry.photo.capture_time.is_none() && photo.capture_time.is_some() {
+            entry.photo.capture_time = photo.capture_time;
+        }
+        entry.photo.favorite |= photo.favorite;
+    }
+
+    order
+        .into_iter()
+        .filter_map(|key| by_key.remove(&key))
+        .collect()
+}
+
+/// Open one archive and stream `entry` through `sink`.
+fn read_entry<R>(
+    archive: &mut zip::ZipArchive<std::io::BufReader<std::fs::File>>,
+    entry: &str,
+    sink: impl FnOnce(&mut (dyn Read + Send)) -> R,
+) -> CoreResult<R> {
+    let mut file = archive
+        .by_name(entry)
+        .map_err(|e| CoreError::invalid(format!("{entry}: {e}")))?;
+    Ok(sink(&mut file))
+}
+
+impl Core {
+    /// Import Google Photos Takeout archives. Blocking; run on its own thread.
+    ///
+    /// `cancel` stops the run at the next photo boundary — an upload already on
+    /// the wire is allowed to finish, so a cancelled import never leaves a
+    /// half-written revision behind.
+    pub(crate) fn import_takeout(
+        &self,
+        archives: Vec<PathBuf>,
+        dry_run: bool,
+        cancel: Arc<AtomicBool>,
+    ) -> CoreResult<ImportSummary> {
+        let job = self.transfers.begin_job("Importing Google Photos");
+        job.detail("reading archives");
+
+        let scan = scan_archives(&archives)?;
+        let mut planned = plan(&scan);
+        let mut summary = ImportSummary {
+            found: planned.len(),
+            skipped_trashed: scan.skipped_trashed,
+            ..Default::default()
+        };
+        job.set_total(planned.len() as u64);
+        info!(
+            archives = archives.len(),
+            photos = summary.found,
+            albums = scan.albums.len(),
+            trashed = summary.skipped_trashed,
+            "takeout scan complete"
+        );
+
+        let photos = self.photos();
+        if self
+            .rt
+            .block_on(photos.get_photos_root())
+            .map_err(|e| CoreError::from_api(&e, "resolve photos library"))?
+            .is_none()
+        {
+            return Err(CoreError::invalid(
+                "this account has no Proton Photos library yet; open Proton Photos once to create it, then import again",
+            ));
+        }
+
+        // Phase 2: which of these are already on the account.
+        job.detail("checking for photos you already have");
+        self.mark_existing(&mut planned, &archives, &mut summary, &cancel)?;
+
+        if dry_run {
+            summary.duplicates = planned.iter().filter(|p| p.uid.is_some()).count();
+            return Ok(summary);
+        }
+
+        // Phase 3: upload what is left, one archive at a time so each zip's
+        // central directory is parsed once.
+        self.upload_planned(&mut planned, &archives, &mut summary, &cancel, &job)?;
+
+        // Phase 4: albums. Attempted even after a cancel — the photos that did
+        // upload should still land in their albums.
+        if !scan.albums.is_empty() {
+            job.detail("sorting photos into albums");
+            if let Err(e) = self.link_albums(&planned, &scan.albums, &mut summary) {
+                warn!(error = %e, "takeout album linking failed");
+            }
+        }
+
+        self.spawn_timeline_refresh();
+        summary.cancelled = cancel.load(Ordering::Relaxed);
+        Ok(summary)
+    }
+
+    /// Fill in `uid` for every planned photo the account already holds.
+    ///
+    /// Two passes on purpose: the name-only query is one request per 150 photos
+    /// and needs no file contents, so the expensive SHA-1 pass only runs for the
+    /// handful of names that actually collide.
+    fn mark_existing(
+        &self,
+        planned: &mut [Planned],
+        archives: &[PathBuf],
+        summary: &mut ImportSummary,
+        cancel: &AtomicBool,
+    ) -> CoreResult<()> {
+        let photos = self.photos();
+        let names: Vec<String> = planned.iter().map(|p| p.photo.name.clone()).collect();
+        let collisions = self
+            .rt
+            .block_on(photos.name_collisions(&names))
+            .map_err(|e| CoreError::from_api(&e, "check for existing photos"))?;
+
+        // Hash the colliding files, grouped by archive so each zip opens once.
+        let mut by_archive: BTreeMap<usize, Vec<usize>> = BTreeMap::new();
+        for (index, planned) in planned.iter().enumerate() {
+            if collisions.get(index).copied().unwrap_or(false) {
+                by_archive
+                    .entry(planned.photo.archive)
+                    .or_default()
+                    .push(index);
+            }
+        }
+
+        // Kept as a pair list, not a map: the duplicate lookup answers in input
+        // order, so the order these were built in is what maps answers back to
+        // planned photos.
+        let mut digests: Vec<(usize, String)> = Vec::new();
+        for (archive_index, indices) in by_archive {
+            if cancel.load(Ordering::Relaxed) {
+                break;
+            }
+            let mut archive = open_archive(archives, archive_index)?;
+            for index in indices {
+                let entry = planned[index].photo.entry.clone();
+                match read_entry(&mut archive, &entry, sha1_of) {
+                    Ok(Ok(digest)) => digests.push((index, digest)),
+                    Ok(Err(e)) | Err(e) => {
+                        warn!(entry, error = %e, "cannot hash takeout entry");
+                    }
+                }
+            }
+        }
+        if digests.is_empty() {
+            return Ok(());
+        }
+
+        let items: Vec<(String, String)> = digests
+            .iter()
+            .map(|(index, digest)| (planned[*index].photo.name.clone(), digest.clone()))
+            .collect();
+        let matches = self
+            .rt
+            .block_on(photos.find_duplicates_many(&items))
+            .map_err(|e| CoreError::from_api(&e, "check for existing photos"))?;
+
+        for (slot, (index, _)) in digests.iter().enumerate() {
+            if let Some(uid) = matches.get(slot).and_then(|uids| uids.first()) {
+                planned[*index].uid = Some(uid.clone());
+                summary.duplicates += 1;
+            }
+        }
+        Ok(())
+    }
+
+    /// Upload every planned photo that is not already on the account.
+    fn upload_planned(
+        &self,
+        planned: &mut [Planned],
+        archives: &[PathBuf],
+        summary: &mut ImportSummary,
+        cancel: &AtomicBool,
+        job: &crate::transfers::JobGuard,
+    ) -> CoreResult<()> {
+        let photos = self.photos();
+        let mut favorites: Vec<NodeUid> = Vec::new();
+
+        let mut by_archive: BTreeMap<usize, Vec<usize>> = BTreeMap::new();
+        for (index, item) in planned.iter().enumerate() {
+            if item.uid.is_none() {
+                by_archive
+                    .entry(item.photo.archive)
+                    .or_default()
+                    .push(index);
+            }
+        }
+
+        for (archive_index, indices) in by_archive {
+            if cancel.load(Ordering::Relaxed) || self.shutdown.is_stopping() {
+                break;
+            }
+            let mut archive = open_archive(archives, archive_index)?;
+
+            for index in indices {
+                if cancel.load(Ordering::Relaxed) || self.shutdown.is_stopping() {
+                    break;
+                }
+                let photo = planned[index].photo.clone();
+                job.detail(photo.name.clone());
+
+                let guard = self.transfers.begin(
+                    photo.name.clone(),
+                    "",
+                    TransferDirection::Upload,
+                    photo.size,
+                );
+                let metadata = PhotoUploadMetadata {
+                    capture_time: photo.capture_time,
+                    ..Default::default()
+                };
+                let uploaded = read_entry(&mut archive, &photo.entry, |reader| {
+                    let counting = CountingReader::new(reader, &guard);
+                    self.rt.block_on(photos.upload_photo_from(
+                        &photo.name,
+                        &photo.media_type,
+                        counting,
+                        photo.size as i64,
+                        Vec::new(),
+                        metadata,
+                        false,
+                    ))
+                });
+                drop(guard);
+                job.step();
+
+                match uploaded {
+                    Ok(Ok(uid)) => {
+                        summary.uploaded += 1;
+                        summary.bytes += photo.size;
+                        if photo.favorite {
+                            favorites.push(uid.clone());
+                        }
+                        planned[index].uid = Some(uid);
+                    }
+                    Ok(Err(e)) => {
+                        summary.failed += 1;
+                        warn!(name = photo.name, error = %e, "takeout photo upload failed");
+                    }
+                    Err(e) => {
+                        summary.failed += 1;
+                        warn!(name = photo.name, error = %e, "cannot read takeout entry");
+                    }
+                }
+            }
+        }
+
+        // Favourites are a separate call: the upload seal takes classification
+        // tags, but `Favorite` is not one of them — it goes through the photos
+        // volume's dedicated favourite endpoint.
+        if !favorites.is_empty() {
+            let updates: Vec<PhotoTagsUpdate> = favorites
+                .into_iter()
+                .map(|node_uid| PhotoTagsUpdate {
+                    node_uid,
+                    tags_to_add: vec![PhotoTag::Favorite],
+                    tags_to_remove: Vec::new(),
+                })
+                .collect();
+            if let Err(e) = self.rt.block_on(photos.update_photos(&updates)) {
+                warn!(error = %e, "marking imported favourites failed");
+            }
+        }
+        Ok(())
+    }
+
+    /// Create the albums the export names that the account lacks, then add each
+    /// album's photos to it.
+    fn link_albums(
+        &self,
+        planned: &[Planned],
+        albums: &[String],
+        summary: &mut ImportSummary,
+    ) -> CoreResult<()> {
+        let photos = self.photos();
+
+        // Existing albums by decrypted name, so a second import of the same
+        // export adds to the album it made the first time instead of a twin.
+        let mut existing: HashMap<String, NodeUid> = HashMap::new();
+        let uids = self
+            .rt
+            .block_on(photos.enumerate_album_node_uids())
+            .map_err(|e| CoreError::from_api(&e, "list albums"))?;
+        if !uids.is_empty() {
+            let albums_nodes = self
+                .rt
+                .block_on(photos.enumerate_nodes(&uids))
+                .map_err(|e| CoreError::from_api(&e, "read albums"))?;
+            for node in albums_nodes {
+                existing.entry(node.name.clone()).or_insert(node.uid);
+            }
+        }
+
+        for title in albums {
+            let members: Vec<NodeUid> = planned
+                .iter()
+                .filter(|item| item.albums.iter().any(|album| album == title))
+                .filter_map(|item| item.uid.clone())
+                .collect();
+            if members.is_empty() {
+                continue;
+            }
+
+            let album_uid = match existing.get(title) {
+                Some(uid) => uid.clone(),
+                None => match self.rt.block_on(photos.create_album(title)) {
+                    Ok(uid) => {
+                        summary.albums_created += 1;
+                        existing.insert(title.clone(), uid.clone());
+                        uid
+                    }
+                    Err(e) => {
+                        warn!(album = title, error = %e, "cannot create album");
+                        continue;
+                    }
+                },
+            };
+
+            match self
+                .rt
+                .block_on(photos.add_photos_to_album(&album_uid, &members))
+            {
+                Ok(outcomes) => {
+                    for (uid, outcome) in outcomes {
+                        match outcome {
+                            Ok(()) => summary.album_links += 1,
+                            // A photo already in the album is the expected
+                            // outcome of a re-run, not a failure worth counting.
+                            Err(e) => {
+                                warn!(album = title, %uid, error = %e, "cannot add photo to album")
+                            }
+                        }
+                    }
+                }
+                Err(e) => warn!(album = title, error = %e, "album addition failed"),
+            }
+        }
+        Ok(())
+    }
+
+    /// Run an import on a background thread, logging its outcome to the activity
+    /// feed. Returns immediately.
+    ///
+    /// Refuses while one is already running: two imports of the same export
+    /// would race each other's duplicate detection and upload everything twice.
+    pub(crate) fn spawn_takeout_import(
+        &self,
+        archives: Vec<PathBuf>,
+        dry_run: bool,
+    ) -> CoreResult<()> {
+        let cancel = Arc::new(AtomicBool::new(false));
+        {
+            let mut state = IMPORT.lock();
+            if state.running {
+                return Err(CoreError::conflict(
+                    "an import is already running; wait for it to finish or cancel it",
+                ));
+            }
+            state.running = true;
+            state.cancel = Some(cancel.clone());
+            state.last = None;
+        }
+
+        let core = self.clone();
+        std::thread::spawn(move || {
+            let outcome = core.import_takeout(archives, dry_run, cancel);
+            {
+                let mut state = IMPORT.lock();
+                state.running = false;
+                state.cancel = None;
+                state.last = outcome.as_ref().ok().cloned();
+            }
+            match outcome {
+                Ok(summary) => {
+                    let mut parts = vec![format!("{} uploaded", summary.uploaded)];
+                    if summary.duplicates > 0 {
+                        parts.push(format!("{} already there", summary.duplicates));
+                    }
+                    if summary.albums_created > 0 {
+                        parts.push(format!("{} albums", summary.albums_created));
+                    }
+                    if summary.failed > 0 {
+                        parts.push(format!("{} failed", summary.failed));
+                    }
+                    if summary.cancelled {
+                        parts.push("cancelled".to_string());
+                    }
+                    core.log_activity(
+                        ActivityKind::Upload,
+                        "Google Photos import",
+                        parts.join(" · "),
+                        summary.failed == 0 && !summary.cancelled,
+                    );
+                }
+                Err(e) => {
+                    warn!(error = %e, "takeout import failed");
+                    core.log_activity(ActivityKind::Upload, "Google Photos import", &e, false);
+                }
+            }
+        });
+        Ok(())
+    }
+}
+
+/// Open one of the import's archives by index.
+fn open_archive(
+    archives: &[PathBuf],
+    index: usize,
+) -> CoreResult<zip::ZipArchive<std::io::BufReader<std::fs::File>>> {
+    let path = archives
+        .get(index)
+        .ok_or_else(|| CoreError::internal(format!("archive {index} is not in the import")))?;
+    let file = std::fs::File::open(path)
+        .map_err(|e| CoreError::invalid(format!("cannot open {}: {e}", path.display())))?;
+    zip::ZipArchive::new(std::io::BufReader::new(file))
+        .map_err(|e| CoreError::invalid(format!("{} is not a readable zip: {e}", path.display())))
+}
+
+/// 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> {
+    let mut hasher = Sha1::new();
+    let mut buffer = vec![0u8; 256 * 1024];
+    loop {
+        let read = reader
+            .read(&mut buffer)
+            .map_err(|e| CoreError::invalid(format!("read failed: {e}")))?;
+        if read == 0 {
+            break;
+        }
+        hasher.update(&buffer[..read]);
+    }
+    Ok(hex_lower(&hasher.finalize()))
+}
+
+fn hex_lower(bytes: &[u8]) -> String {
+    let mut out = String::with_capacity(bytes.len() * 2);
+    for byte in bytes {
+        out.push_str(&format!("{byte:02x}"));
+    }
+    out
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pdfs_core::takeout::TakeoutPhoto;
+
+    fn photo(name: &str, size: u64, bucket: Bucket) -> TakeoutPhoto {
+        TakeoutPhoto {
+            archive: 0,
+            entry: format!("Takeout/Google Photos/x/{name}"),
+            name: name.to_string(),
+            size,
+            media_type: "image/jpeg".to_string(),
+            capture_time: None,
+            favorite: false,
+            bucket,
+        }
+    }
+
+    #[test]
+    fn album_copies_of_one_photo_fold_into_a_single_upload() {
+        let scan = TakeoutScan {
+            photos: vec![
+                photo("IMG_1.jpg", 100, Bucket::Timeline),
+                photo("IMG_1.jpg", 100, Bucket::Album("Iceland".into())),
+                photo("IMG_1.jpg", 100, Bucket::Album("Best of".into())),
+                photo("IMG_2.jpg", 200, Bucket::Timeline),
+            ],
+            albums: vec!["Iceland".into(), "Best of".into()],
+            ..Default::default()
+        };
+
+        let planned = plan(&scan);
+        assert_eq!(planned.len(), 2, "the three copies are one upload");
+        assert_eq!(planned[0].albums, vec!["Iceland", "Best of"]);
+        assert!(planned[1].albums.is_empty());
+    }
+
+    #[test]
+    fn same_name_different_size_stays_two_photos() {
+        let scan = TakeoutScan {
+            photos: vec![
+                photo("IMG_1.jpg", 100, Bucket::Timeline),
+                photo("IMG_1.jpg", 101, Bucket::Album("Iceland".into())),
+            ],
+            ..Default::default()
+        };
+
+        assert_eq!(plan(&scan).len(), 2);
+    }
+
+    #[test]
+    fn metadata_from_any_copy_survives_the_fold() {
+        // Only the album copy carries a sidecar; the fold must not lose it.
+        let mut bare = photo("IMG_1.jpg", 100, Bucket::Timeline);
+        bare.capture_time = None;
+        let mut rich = photo("IMG_1.jpg", 100, Bucket::Album("Iceland".into()));
+        rich.capture_time = Some(1_560_000_000);
+        rich.favorite = true;
+
+        let planned = plan(&TakeoutScan {
+            photos: vec![bare, rich],
+            ..Default::default()
+        });
+
+        assert_eq!(planned[0].photo.capture_time, Some(1_560_000_000));
+        assert!(planned[0].photo.favorite);
+    }
+
+    #[test]
+    fn sha1_matches_the_known_digest_of_abc() {
+        let mut reader: &[u8] = b"abc";
+        assert_eq!(
+            sha1_of(&mut reader).unwrap(),
+            "a9993e364706816aba3e25717850c26c9cd0d89d"
+        );
+    }
+}

crates/pdfs-fuse/src/transfers.rs

@@ -19,7 +19,7 @@ use parking_lot::Mutex;
 use std::collections::HashMap;
 use std::io::{Read, Write};
 use std::sync::Arc;
-use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
 use std::time::Instant;
 
 use pdfs_core::control::{JobItem, TransferDirection, TransferItem};
@@ -272,20 +272,50 @@ impl<R: Read> Read for OwnedCountingReader<R> {
     }
 }
 
-/// A [`Read`] that tallies bytes read through a [`TransferGuard`] (upload path).
+/// A [`Read`] that tallies bytes read through a [`TransferGuard`] (upload path),
+/// and can be told to stop.
 pub struct CountingReader<'a, R> {
     inner: R,
     guard: &'a TransferGuard,
+    cancel: Option<Arc<AtomicBool>>,
 }
 
 impl<'a, R: Read> CountingReader<'a, R> {
     pub fn new(inner: R, guard: &'a TransferGuard) -> Self {
-        Self { inner, guard }
+        Self {
+            inner,
+            guard,
+            cancel: None,
+        }
+    }
+
+    /// Abandon the upload as soon as the SDK asks for its next bytes when
+    /// `cancel` is set.
+    ///
+    /// This is the only cancellation point an upload has: the SDK takes a plain
+    /// blocking [`Read`] and pulls from it a block at a time, so refusing to
+    /// hand over the next block is what stops it. Used when a newer revision of
+    /// the same file is queued — the bytes on the wire have already been
+    /// superseded, and finishing them only spends uplink on a revision the next
+    /// op replaces.
+    pub fn with_cancel(mut self, cancel: Arc<AtomicBool>) -> Self {
+        self.cancel = Some(cancel);
+        self
     }
 }
 
 impl<R: Read> Read for CountingReader<'_, R> {
     fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        if let Some(cancel) = &self.cancel
+            && cancel.load(Ordering::Relaxed)
+        {
+            // Not `Ok(0)`: a short read is how this reader says "end of file",
+            // and the SDK would seal a truncated revision from it.
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::Interrupted,
+                "upload superseded by a newer write",
+            ));
+        }
         let n = self.inner.read(buf)?;
         self.guard.add(n as u64);
         Ok(n)

crates/pdfs-fuse/src/upload.rs

@@ -171,7 +171,7 @@ impl Core {
                     stats.bytes += size;
                     match self.fetch_node(&uid) {
                         Ok(node) => {
-                            let mut st = self.state.lock();
+                            let mut st = self.state();
                             let ino = st.intern(parent_ino, node);
                             if let Some(kids) = st.children.get_mut(&parent_ino)
                                 && !kids.contains(&ino)
@@ -216,7 +216,7 @@ impl Core {
         self.ensure_children(pino)
             .map_err(|e| self.errno_error(e, "enumerate"))?;
         let existing = {
-            let st = self.state.lock();
+            let st = self.state();
             st.children.get(&pino).and_then(|kids| {
                 kids.iter().find_map(|ino| {
                     st.entries
@@ -243,7 +243,7 @@ impl Core {
         let node = self
             .fetch_node(&new_uid)
             .map_err(|e| self.errno_error(e, "fetch node"))?;
-        let mut st = self.state.lock();
+        let mut st = self.state();
         let ino = st.intern(pino, node);
         if let Some(kids) = st.children.get_mut(&pino)
             && !kids.contains(&ino)

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

@@ -14,6 +14,7 @@ use pages::photos::*;
 use pages::shared::*;
 use pages::shared_by_me::*;
 use pages::status::*;
+use pages::takeout::*;
 use pages::trash::*;
 use pages::verify::*;
 use widgets::details::*;
@@ -46,10 +47,10 @@ use pdfs_core::config::AppDirs;
 
 use pdfs_core::control::{
     ActivityEntry, ActivityKind, AlbumInfo, BookmarkInfo, DeviceInfo, DirEntry, ErrorKind,
-    InvitationInfo, JobItem, PhotoItem, PhotoKind, PublicLinkInfo, RefreshScope, Request, Response,
-    RestorableFolder, RestoreItem, SearchHit, ShareEntry, ShareEntryKind, SharedItem,
-    SyncFolderInfo, SyncPhase, SyncProgress, TransferDirection, TransferItem, pending_summary,
-    send,
+    ImportSummary, InvitationInfo, JobItem, PhotoItem, PhotoKind, PublicLinkInfo, RefreshScope,
+    Request, Response, RestorableFolder, RestoreItem, SearchHit, ShareEntry, ShareEntryKind,
+    SharedItem, SyncFolderInfo, SyncPhase, SyncProgress, TransferDirection, TransferItem,
+    pending_summary, send,
 };
 
 use pdfs_core::mounts::{MountAccess, MountKind, MountMode, MountSpec};
@@ -120,6 +121,7 @@ struct Ui {
     pub(crate) devices: DevicesState,
     pub(crate) locations: LocationsState,
     pub(crate) activity: ActivityState,
+    pub(crate) takeout: TakeoutState,
 }
 
 impl Ui {
@@ -246,7 +248,10 @@ fn load_proton_theme() {
          .navigation-sidebar row {{ border-radius: 8px; margin: 2px 6px; }}\n\
          .navigation-sidebar row:selected {{ background: alpha({PROTON_PURPLE}, 0.16); color: {PROTON_PURPLE}; font-weight: 600; }}\n\
          .navigation-sidebar row:selected image {{ color: {PROTON_PURPLE}; }}\n\
-         .file-tile:selected, .file-tile:hover:selected {{ background: alpha({PROTON_PURPLE}, 0.20); }}\n"
+         .file-tile:selected, .file-tile:hover:selected {{ background: alpha({PROTON_PURPLE}, 0.20); }}\n\
+         .bulk-bar {{ padding: 6px 8px; border-radius: 12px; background: alpha({PROTON_PURPLE}, 0.12); }}\n\
+         .dropzone {{ border: 2px dashed alpha(currentColor, 0.25); border-radius: 16px; padding: 28px 18px; transition: background 160ms ease, border-color 160ms ease; }}\n\
+         .dropzone-active {{ border-color: {PROTON_PURPLE}; background: alpha({PROTON_PURPLE}, 0.10); }}\n"
     );
     let provider = gtk4::CssProvider::new();
     provider.load_from_string(&css);
@@ -285,6 +290,7 @@ fn build_window(app: &adw::Application) {
     let (locations_page, locations_widgets) = build_locations_page();
     let (activity_page, activity_widgets) = build_activity_page();
     let (trash_page, trash_widgets) = build_trash_page();
+    let (takeout_page, takeout_widgets) = build_takeout_page();
     stack.add_named(&login_page, Some("login"));
     stack.add_named(&main_page, Some("main"));
     stack.add_named(&browser_page, Some("browser"));
@@ -295,6 +301,7 @@ fn build_window(app: &adw::Application) {
     stack.add_named(&locations_page, Some("locations"));
     stack.add_named(&activity_page, Some("activity"));
     stack.add_named(&trash_page, Some("trash"));
+    stack.add_named(&takeout_page, Some("takeout"));
 
     // Sidebar: the signed-in destinations. Selecting a row swaps the page stack;
     // `sync_sidebar` pushes the other way when navigation happens elsewhere (e.g.
@@ -362,6 +369,8 @@ fn build_window(app: &adw::Application) {
             budget_row: main_widgets.budget_row.clone(),
             mountpoint_row: main_widgets.mountpoint_row.clone(),
             settings_suppress: Cell::new(false),
+            budget_source: RefCell::new(None),
+            pins_expanded: Cell::new(false),
             pins_group: main_widgets.pins_group.clone(),
             pin_rows: RefCell::new(Vec::new()),
             pins_state: RefCell::new(None),
@@ -382,6 +391,13 @@ fn build_window(app: &adw::Application) {
             upload: browser_widgets.upload.clone(),
             upload_folder: browser_widgets.upload_folder.clone(),
             search_source: RefCell::new(None),
+            views: browser_widgets.views.clone(),
+            bulk: browser_widgets.bulk.clone(),
+            bulk_label: browser_widgets.bulk_label.clone(),
+            bulk_trash: browser_widgets.bulk_trash.clone(),
+            bulk_pin: browser_widgets.bulk_pin.clone(),
+            bulk_unpin: browser_widgets.bulk_unpin.clone(),
+            empty_actions: browser_widgets.empty_actions.clone(),
         },
         details: DetailsState {
             details: browser_widgets.details,
@@ -407,6 +423,8 @@ fn build_window(app: &adw::Application) {
             retry: gallery_widgets.retry.clone(),
             more: gallery_widgets.more.clone(),
             upload: gallery_widgets.upload.clone(),
+            import: gallery_widgets.import.clone(),
+            empty_actions: gallery_widgets.empty_actions.clone(),
             title: gallery_widgets.title.clone(),
             subtitle: gallery_widgets.subtitle.clone(),
             albums: gallery_widgets.albums.clone(),
@@ -494,6 +512,24 @@ fn build_window(app: &adw::Application) {
             inflight: Cell::new(false),
             key: RefCell::new(None),
         },
+        takeout: TakeoutState {
+            archives: RefCell::new(Vec::new()),
+            list_group: takeout_widgets.list_group.clone(),
+            rows: RefCell::new(Vec::new()),
+            dropzone: takeout_widgets.dropzone.clone(),
+            scan_button: takeout_widgets.scan_button.clone(),
+            import_button: takeout_widgets.import_button.clone(),
+            cancel_button: takeout_widgets.cancel_button.clone(),
+            clear_button: takeout_widgets.clear_button.clone(),
+            progress_group: takeout_widgets.progress_group.clone(),
+            progress_label: takeout_widgets.progress_label.clone(),
+            progress_bar: takeout_widgets.progress_bar.clone(),
+            summary_group: takeout_widgets.summary_group.clone(),
+            summary_rows: RefCell::new(Vec::new()),
+            inflight: Cell::new(false),
+            running: Cell::new(false),
+            dry_run: Cell::new(false),
+        },
     });
     wire_login(&ui);
     wire_logout(&ui, &main_widgets.logout_button);
@@ -501,9 +537,16 @@ fn build_window(app: &adw::Application) {
         &ui,
         &main_widgets.purge_button,
         &main_widgets.mountpoint_button,
+        &main_widgets.import_row,
     );
     wire_sidebar(&ui);
     wire_browser(&ui, &browser_widgets.grid, &browser_widgets.column_view);
+    wire_bulk(
+        &ui,
+        &browser_widgets.bulk_clear,
+        &browser_widgets.empty_upload,
+        &browser_widgets.empty_new_folder,
+    );
     wire_browser_actions(
         &ui,
         &browser_widgets.new_folder,
@@ -513,6 +556,11 @@ fn build_window(app: &adw::Application) {
     wire_details(&ui);
     wire_search(&ui);
     wire_gallery(&ui, &gallery_widgets.list, &gallery_widgets.scroll);
+    wire_gallery_empty(
+        &ui,
+        &gallery_widgets.empty_upload,
+        &gallery_widgets.empty_import,
+    );
     wire_albums(&ui);
     wire_trash(&ui, &trash_widgets.list, &trash_widgets.empty);
     wire_shared(&ui, &shared_widgets.retry, &shared_widgets.add_bookmark);
@@ -520,6 +568,7 @@ fn build_window(app: &adw::Application) {
     wire_devices(&ui, &devices_widgets.retry, &devices_widgets.restore);
     wire_locations(&ui, &locations_widgets.retry, &locations_widgets.add_folder);
     wire_activity(&ui, &activity_widgets.retry);
+    wire_takeout(&ui, &takeout_widgets);
     wire_refresh(
         &ui,
         &[
@@ -559,6 +608,9 @@ fn build_window(app: &adw::Application) {
             // every visit to stay live.
             Some("activity") => load_activity(&ui_nav),
             Some("trash") => load_trash(&ui_nav),
+            // The import runs in the daemon and outlives this page, so arriving
+            // here asks straight away whether one is in flight.
+            Some("takeout") => refresh_takeout(&ui_nav),
             _ => {}
         }
     });
@@ -644,6 +696,17 @@ fn build_sidebar() -> (adw::NavigationPage, gtk4::ListBox) {
     (page, list)
 }
 
+/// The sidebar destination a page belongs under. Most pages are their own
+/// destination; a sub-page reached from one (Import, off Settings) has no row of
+/// its own and answers with its parent, so the sidebar highlights where the user
+/// came from rather than clearing — which would read as "nowhere".
+fn destination_of(page: &str) -> &str {
+    match page {
+        "takeout" => "main",
+        other => other,
+    }
+}
+
 /// Selecting a sidebar row navigates the page stack. The reverse direction (stack
 /// → sidebar highlight) is [`sync_sidebar`], so the two can't fight: this handler
 /// only ever writes the stack.
@@ -654,7 +717,11 @@ fn wire_sidebar(ui: &Rc<Ui>) {
         let Some((page, _, _)) = DESTINATIONS.get(row.index() as usize) else {
             return;
         };
-        if ui_row.stack.visible_child_name().as_deref() != Some(*page) {
+        // Compared by *destination*, not by page: while a sub-page is open its
+        // parent's row is the selected one, and re-asserting it here would kick
+        // the user off the sub-page the moment they arrived.
+        let current = ui_row.stack.visible_child_name();
+        if current.as_deref().map(destination_of) != Some(*page) {
             ui_row.stack.set_visible_child_name(page);
         }
     });
@@ -755,6 +822,7 @@ fn sync_sidebar(ui: &Rc<Ui>) {
     let Some(current) = ui.stack.visible_child_name() else {
         return;
     };
+    let current = destination_of(&current);
     let index = DESTINATIONS
         .iter()
         .position(|(page, _, _)| *page == current);
@@ -776,6 +844,22 @@ fn toast(ui: &Rc<Ui>, message: &str) {
     ui.toasts.add_toast(adw::Toast::new(message));
 }
 
+/// Show a toast that offers one follow-up action — an Undo, or a way to the page
+/// the outcome landed on.
+///
+/// Given a longer timeout than a plain toast: an action the user has to notice,
+/// read and reach is not the same ask as a line of confirmation they can ignore.
+fn toast_action(ui: &Rc<Ui>, message: &str, label: &str, action: impl Fn(&Rc<Ui>) + 'static) {
+    let toast = adw::Toast::builder()
+        .title(message)
+        .button_label(label)
+        .timeout(8)
+        .build();
+    let ui_action = ui.clone();
+    toast.connect_button_clicked(move |_| action(&ui_action));
+    ui.toasts.add_toast(toast);
+}
+
 /// Show a toast for a failure. Same surface as [`toast`], but the message is
 /// prefixed with what was being attempted, since a bare daemon error ("no such
 /// file") reads as noise without it.
@@ -913,7 +997,13 @@ fn install_shortcuts(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
             // browser-only bindings.
             gtk4::gdk::Key::F5 => reload_current_page(&ui),
             gtk4::gdk::Key::r | gtk4::gdk::Key::R if ctrl => reload_current_page(&ui),
-            gtk4::gdk::Key::f | gtk4::gdk::Key::F if ctrl && on_browser => {
+            // Search lives on Files, but the shortcut works from anywhere:
+            // wanting to find a file is not a reason to first have to remember
+            // which page owns the search box.
+            gtk4::gdk::Key::f | gtk4::gdk::Key::F if ctrl => {
+                if !on_browser {
+                    ui.stack.set_visible_child_name("browser");
+                }
                 ui.browser.search.grab_focus();
             }
             gtk4::gdk::Key::n | gtk4::gdk::Key::N if ctrl && on_browser => prompt_new_folder(&ui),
@@ -923,12 +1013,21 @@ fn install_shortcuts(ui: &Rc<Ui>, window: &adw::ApplicationWindow) {
                     prompt_rename(&ui, &entry);
                 }
             }
+            // Acts on the whole selection: Delete with five files highlighted
+            // means those five, not whichever one the details pane happens to
+            // be describing.
             gtk4::gdk::Key::Delete if on_browser => {
-                if let Some(entry) = selected_entry(&ui) {
-                    prompt_delete(&ui, &entry);
+                let entries = selected_entries(&ui);
+                if !entries.is_empty() {
+                    prompt_delete_many(&ui, entries);
                 }
             }
-            gtk4::gdk::Key::Escape if on_browser && ui.browser.split.shows_sidebar() => {
+            gtk4::gdk::Key::Escape
+                if on_browser
+                    && (ui.browser.split.shows_sidebar() || ui.browser.bulk.reveals_child()) =>
+            {
+                clear_selection(&ui);
+                sync_bulk_bar(&ui);
                 hide_details(&ui);
             }
             _ => return glib::Propagation::Proceed,

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

@@ -31,6 +31,21 @@ pub(crate) struct BrowserState {
     /// Pending debounce timer for the search box; replaced on every keystroke so
     /// only the last pause actually fires a [`Request::Search`].
     pub(crate) search_source: RefCell<Option<glib::SourceId>>,
+    /// The grid/list view stack, read to find out which of the two selections is
+    /// the one the user is actually working in.
+    pub(crate) views: gtk4::Stack,
+    /// The bulk-action bar, revealed once more than one entry is selected.
+    pub(crate) bulk: gtk4::Revealer,
+    pub(crate) bulk_label: gtk4::Label,
+    /// Bulk buttons, sensitive only where they apply (offline state is a
+    /// file-only notion, so a folder in the selection disables those two).
+    pub(crate) bulk_trash: gtk4::Button,
+    pub(crate) bulk_pin: gtk4::Button,
+    pub(crate) bulk_unpin: gtk4::Button,
+    /// Upload / New folder offered on the *empty folder* status page, so that
+    /// state is a place to act rather than a dead end. Hidden on every other
+    /// status (a load error is not the moment to offer an upload).
+    pub(crate) empty_actions: gtk4::Box,
 }
 
 /// Idle pause after the last keystroke before a search query is sent, so typing
@@ -76,9 +91,20 @@ pub(crate) struct BrowserWidgets {
     pub(crate) split: adw::OverlaySplitView,
     pub(crate) details: DetailsWidgets,
     /// The two selection models, so a selection change can drive the details pane
-    /// and so an action can re-read the entry the user has highlighted.
-    pub(crate) grid_selection: gtk4::SingleSelection,
-    pub(crate) list_selection: gtk4::SingleSelection,
+    /// and so an action can re-read the entries the user has highlighted.
+    pub(crate) grid_selection: gtk4::MultiSelection,
+    pub(crate) list_selection: gtk4::MultiSelection,
+    /// The grid/list stack, so the page can tell which selection is live.
+    pub(crate) views: gtk4::Stack,
+    pub(crate) bulk: gtk4::Revealer,
+    pub(crate) bulk_label: gtk4::Label,
+    pub(crate) bulk_trash: gtk4::Button,
+    pub(crate) bulk_pin: gtk4::Button,
+    pub(crate) bulk_unpin: gtk4::Button,
+    pub(crate) bulk_clear: gtk4::Button,
+    pub(crate) empty_actions: gtk4::Box,
+    pub(crate) empty_upload: gtk4::Button,
+    pub(crate) empty_new_folder: gtk4::Button,
 }
 
 pub(crate) fn build_browser_page() -> (gtk4::Widget, BrowserWidgets) {
@@ -166,19 +192,34 @@ pub(crate) fn build_browser_page() -> (gtk4::Widget, BrowserWidgets) {
     retry.add_css_class("pill");
     retry.add_css_class("suggested-action");
     retry.set_visible(false);
+    // The empty-folder state's way out. `StatusPage` takes one child, so Retry
+    // and these share a box; each is shown only for the state it belongs to.
+    let empty_upload = gtk4::Button::builder().label("Upload files").build();
+    empty_upload.add_css_class("pill");
+    empty_upload.add_css_class("suggested-action");
+    let empty_new_folder = gtk4::Button::builder().label("New folder").build();
+    empty_new_folder.add_css_class("pill");
+    let empty_actions = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
+    empty_actions.set_halign(gtk4::Align::Center);
+    empty_actions.set_visible(false);
+    empty_actions.append(&empty_upload);
+    empty_actions.append(&empty_new_folder);
+
+    let status_child = gtk4::Box::new(gtk4::Orientation::Vertical, 12);
+    status_child.append(&retry);
+    status_child.append(&empty_actions);
+
     let status = adw::StatusPage::builder()
         .icon_name("folder-symbolic")
         .vexpand(true)
-        .child(&retry)
+        .child(&status_child)
         .build();
     status.add_css_class("compact");
 
-    // Icon grid.
-    let grid_selection = gtk4::SingleSelection::builder()
-        .model(&model)
-        .autoselect(false)
-        .can_unselect(true)
-        .build();
+    // Icon grid. Multi-select: acting on a batch is the common case for trashing
+    // and for taking a folder's worth of files offline, and doing it one
+    // confirmation dialog at a time is not a workflow.
+    let grid_selection = gtk4::MultiSelection::new(Some(model.clone()));
     let grid = gtk4::GridView::builder()
         .model(&grid_selection)
         .min_columns(2)
@@ -190,12 +231,8 @@ pub(crate) fn build_browser_page() -> (gtk4::Widget, BrowserWidgets) {
         .child(&grid)
         .build();
 
-    // Column list.
-    let list_selection = gtk4::SingleSelection::builder()
-        .model(&model)
-        .autoselect(false)
-        .can_unselect(true)
-        .build();
+    // Column list, with its own selection over the same model.
+    let list_selection = gtk4::MultiSelection::new(Some(model.clone()));
     let column_view = gtk4::ColumnView::builder().model(&list_selection).build();
     column_view.add_css_class("data-table");
     let column_scroll = gtk4::ScrolledWindow::builder()
@@ -239,12 +276,51 @@ pub(crate) fn build_browser_page() -> (gtk4::Widget, BrowserWidgets) {
         .sidebar(&details_pane)
         .build();
 
+    // Bulk-action bar. A revealer rather than a hidden box so it slides in
+    // instead of making the whole view jump when a second entry is selected.
+    let bulk_label = gtk4::Label::builder().hexpand(true).xalign(0.0).build();
+    let bulk_pin = gtk4::Button::builder()
+        .label("Keep offline")
+        .valign(gtk4::Align::Center)
+        .build();
+    bulk_pin.add_css_class("flat");
+    let bulk_unpin = gtk4::Button::builder()
+        .label("Remove offline copy")
+        .valign(gtk4::Align::Center)
+        .build();
+    bulk_unpin.add_css_class("flat");
+    let bulk_trash = gtk4::Button::builder()
+        .label("Move to Trash")
+        .valign(gtk4::Align::Center)
+        .build();
+    bulk_trash.add_css_class("destructive-action");
+    let bulk_clear = gtk4::Button::builder()
+        .icon_name("window-close-symbolic")
+        .tooltip_text("Clear selection (Esc)")
+        .valign(gtk4::Align::Center)
+        .build();
+    bulk_clear.add_css_class("flat");
+    bulk_clear.add_css_class("circular");
+    let bulk_box = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
+    bulk_box.add_css_class("toolbar");
+    bulk_box.add_css_class("bulk-bar");
+    bulk_box.append(&bulk_label);
+    bulk_box.append(&bulk_pin);
+    bulk_box.append(&bulk_unpin);
+    bulk_box.append(&bulk_trash);
+    bulk_box.append(&bulk_clear);
+    let bulk = gtk4::Revealer::builder()
+        .transition_type(gtk4::RevealerTransitionType::SlideDown)
+        .child(&bulk_box)
+        .build();
+
     let inner = gtk4::Box::new(gtk4::Orientation::Vertical, 12);
     inner.set_margin_top(12);
     inner.set_margin_bottom(12);
     inner.set_margin_start(12);
     inner.set_margin_end(12);
     inner.append(&header);
+    inner.append(&bulk);
     inner.append(&split);
 
     (
@@ -267,6 +343,16 @@ pub(crate) fn build_browser_page() -> (gtk4::Widget, BrowserWidgets) {
             details,
             grid_selection,
             list_selection,
+            views: view_stack,
+            bulk,
+            bulk_label,
+            bulk_trash,
+            bulk_pin,
+            bulk_unpin,
+            bulk_clear,
+            empty_actions,
+            empty_upload,
+            empty_new_folder,
         },
     )
 }
@@ -278,10 +364,273 @@ pub(crate) fn browser_status(ui: &Rc<Ui>, icon: &str, title: &str, description:
     ui.browser.status.set_title(title);
     ui.browser.status.set_description(Some(description));
     ui.browser.retry.set_visible(retry);
+    // Only the empty-folder state offers a way to fill the folder; every other
+    // status (loading, offline, error) turns them back off.
+    ui.browser.empty_actions.set_visible(false);
     ui.browser.content.set_visible_child_name("status");
     hide_details(ui);
 }
 
+/// The selection model of whichever view is on screen. The grid and the list
+/// each own one over the same model, so "what is selected" depends on which the
+/// user is looking at.
+pub(crate) fn active_selection(ui: &Rc<Ui>) -> gtk4::MultiSelection {
+    if ui.browser.views.visible_child_name().as_deref() == Some("list") {
+        ui.details.list_selection.clone()
+    } else {
+        ui.details.grid_selection.clone()
+    }
+}
+
+/// Every entry highlighted in the view on screen, in model order.
+///
+/// Walks the model rather than the selection bitset: a listing is at most a few
+/// thousand rows, and asking each position whether it is selected keeps this
+/// free of bitset-iterator lifetimes for no measurable cost.
+pub(crate) fn selected_entries(ui: &Rc<Ui>) -> Vec<DirEntry> {
+    let selection = active_selection(ui);
+    let count = selection.n_items();
+    (0..count)
+        .filter(|i| selection.is_selected(*i))
+        .filter_map(|i| entry_at(Some(&selection), i))
+        .collect()
+}
+
+/// Drop the selection in both views, which also retracts the bulk bar.
+pub(crate) fn clear_selection(ui: &Rc<Ui>) {
+    ui.details.grid_selection.unselect_all();
+    ui.details.list_selection.unselect_all();
+}
+
+/// Reflect the current selection in the bulk bar: how many are selected, and
+/// which bulk actions apply to that mix. Offline state is a file-only notion, so
+/// a folder anywhere in the selection disables the two pin buttons rather than
+/// half-failing once pressed.
+pub(crate) fn sync_bulk_bar(ui: &Rc<Ui>) {
+    let entries = selected_entries(ui);
+    // One selected entry is the details pane's job; the bar is for a batch.
+    if entries.len() < 2 {
+        ui.browser.bulk.set_reveal_child(false);
+        return;
+    }
+    let files_only = entries.iter().all(|e| !e.is_dir);
+    let any_pinned = entries.iter().any(|e| e.pinned);
+    let any_unpinned = entries.iter().any(|e| !e.pinned);
+    let mounted = *ui.mounted.borrow();
+    ui.browser
+        .bulk_label
+        .set_label(&format!("{} selected", entries.len()));
+    ui.browser.bulk_trash.set_sensitive(mounted);
+    ui.browser
+        .bulk_pin
+        .set_sensitive(mounted && files_only && any_unpinned);
+    ui.browser
+        .bulk_unpin
+        .set_sensitive(mounted && files_only && any_pinned);
+    ui.browser.bulk.set_reveal_child(true);
+}
+
+/// Confirm and move every selected entry to Trash.
+///
+/// One dialog for the batch, one pass over the daemon, one toast — and one Undo
+/// that restores the whole batch, because a mis-aimed bulk delete is exactly the
+/// action a user most needs to take back.
+pub(crate) fn prompt_delete_many(ui: &Rc<Ui>, entries: Vec<DirEntry>) {
+    if entries.len() < 2 {
+        if let Some(entry) = entries.first() {
+            prompt_delete(ui, entry);
+        }
+        return;
+    }
+    let win = ui_window(ui);
+    let dialog = adw::AlertDialog::builder()
+        .heading("Move to Trash")
+        .body(format!(
+            "Move {} items to Trash? Anything inside a selected folder goes with it.",
+            entries.len()
+        ))
+        .build();
+    dialog.add_response("cancel", "Cancel");
+    dialog.add_response("trash", "Move to Trash");
+    dialog.set_response_appearance("trash", adw::ResponseAppearance::Destructive);
+    dialog.set_default_response(Some("cancel"));
+    dialog.set_close_response("cancel");
+
+    let ui = ui.clone();
+    dialog.connect_response(None, move |_, resp| {
+        if resp == "trash" {
+            run_bulk_delete(&ui, entries.clone());
+        }
+    });
+    dialog.present(win.as_ref());
+}
+
+/// Trash a batch, one request at a time.
+///
+/// Sequential rather than parallel: the daemon serialises these anyway, and a
+/// burst of threads against one socket buys nothing but a harder failure to
+/// report. Partial success is reported as such — the entries that did move are
+/// still restorable through the Undo.
+pub(crate) fn run_bulk_delete(ui: &Rc<Ui>, entries: Vec<DirEntry>) {
+    if !*ui.mounted.borrow() {
+        toast_error(
+            ui,
+            "Couldn't move to Trash",
+            "Proton Drive isn't connected.",
+        );
+        return;
+    }
+    let socket = ui.dirs.control_socket();
+    // A one-entry batch is still a batch, but it is worth naming in the toast:
+    // "Moved “notes.txt” to Trash" tells the user which file far better than a
+    // count of one does.
+    let single = (entries.len() == 1).then(|| entries[0].name.clone());
+    let paths: Vec<(String, String)> = entries
+        .iter()
+        .map(|e| (entry_rel(ui, e), e.uid.clone()))
+        .collect();
+    ui.busy_begin();
+    clear_selection(ui);
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let mut trashed: Vec<String> = Vec::new();
+        let mut failure: Option<String> = None;
+        for (path, uid) in paths {
+            let rx = spawn_request(socket.clone(), Request::Delete { path });
+            match rx.recv().await {
+                Ok(Ok(Response::Ok { .. })) => trashed.push(uid),
+                Ok(Ok(Response::Error { message, .. })) => {
+                    failure.get_or_insert(message);
+                }
+                _ => {
+                    failure.get_or_insert_with(|| "The mount service didn't respond.".to_string());
+                }
+            }
+        }
+        ui.busy_end();
+        reload_listing(&ui);
+        match (trashed.len(), failure) {
+            (0, Some(message)) => toast_error(&ui, "Couldn't move to Trash", &message),
+            (0, None) => {}
+            (n, failure) => {
+                let message = match (failure, &single) {
+                    (Some(_), _) => format!("Moved {n} items to Trash — some couldn't be moved"),
+                    (None, Some(name)) => format!("Moved “{name}” to Trash"),
+                    (None, None) => format!("Moved {n} items to Trash"),
+                };
+                toast_action(&ui, &message, "Undo", move |ui| {
+                    restore_uids(ui, trashed.clone(), n);
+                });
+            }
+        }
+    });
+}
+
+/// Put trashed nodes back where they came from — the Undo behind a trash toast.
+pub(crate) fn restore_uids(ui: &Rc<Ui>, uids: Vec<String>, count: usize) {
+    run_mutation(
+        ui,
+        Request::Restore { uids },
+        if count == 1 {
+            "Restored from Trash".to_string()
+        } else {
+            format!("Restored {count} items from Trash")
+        },
+        "Couldn't restore from Trash",
+    );
+}
+
+/// Pin or unpin every selected file, one request at a time.
+pub(crate) fn run_bulk_pin(ui: &Rc<Ui>, entries: Vec<DirEntry>, pin: bool) {
+    let socket = ui.dirs.control_socket();
+    // Only the entries that need changing: re-pinning an already-pinned file is
+    // a wasted round-trip, and it would inflate the count the toast reports.
+    let paths: Vec<String> = entries
+        .iter()
+        .filter(|e| !e.is_dir && e.pinned != pin)
+        .map(|e| entry_rel(ui, e))
+        .collect();
+    if paths.is_empty() {
+        return;
+    }
+    ui.busy_begin();
+    clear_selection(ui);
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let mut done = 0usize;
+        let mut failure: Option<String> = None;
+        for path in paths {
+            let req = if pin {
+                Request::Pin { path }
+            } else {
+                Request::Unpin { path }
+            };
+            let rx = spawn_request(socket.clone(), req);
+            match rx.recv().await {
+                Ok(Ok(Response::Ok { .. })) => done += 1,
+                Ok(Ok(Response::Error { message, .. })) => {
+                    failure.get_or_insert(message);
+                }
+                _ => {
+                    failure.get_or_insert_with(|| "The mount service didn't respond.".to_string());
+                }
+            }
+        }
+        ui.busy_end();
+        load_browser(&ui);
+        match (done, failure) {
+            (0, Some(message)) => toast_error(&ui, "Couldn't change offline state", &message),
+            (0, None) => {}
+            (n, _) => toast(
+                &ui,
+                &if pin {
+                    format!("{n} files are now available offline")
+                } else {
+                    format!("{n} files are no longer kept offline")
+                },
+            ),
+        }
+    });
+}
+
+/// Wire the bulk-action bar and the empty-folder state's buttons.
+pub(crate) fn wire_bulk(
+    ui: &Rc<Ui>,
+    bulk_clear: &gtk4::Button,
+    empty_upload: &gtk4::Button,
+    empty_new_folder: &gtk4::Button,
+) {
+    let ui_trash = ui.clone();
+    ui.browser
+        .bulk_trash
+        .connect_clicked(move |_| prompt_delete_many(&ui_trash, selected_entries(&ui_trash)));
+    let ui_pin = ui.clone();
+    ui.browser
+        .bulk_pin
+        .connect_clicked(move |_| run_bulk_pin(&ui_pin, selected_entries(&ui_pin), true));
+    let ui_unpin = ui.clone();
+    ui.browser
+        .bulk_unpin
+        .connect_clicked(move |_| run_bulk_pin(&ui_unpin, selected_entries(&ui_unpin), false));
+    let ui_clear = ui.clone();
+    bulk_clear.connect_clicked(move |_| {
+        clear_selection(&ui_clear);
+        sync_bulk_bar(&ui_clear);
+    });
+
+    // Switching views switches which selection is live, so the bar has to be
+    // re-derived rather than left showing the other view's count.
+    let ui_view = ui.clone();
+    ui.browser
+        .views
+        .connect_visible_child_name_notify(move |_| sync_bulk_bar(&ui_view));
+
+    let ui_upload = ui.clone();
+    empty_upload.connect_clicked(move |_| prompt_upload(&ui_upload));
+    let ui_new = ui.clone();
+    empty_new_folder.connect_clicked(move |_| prompt_new_folder(&ui_new));
+}
+
 /// Swap the Files content area back to the grid/list views.
 pub(crate) fn browser_views(ui: &Rc<Ui>) {
     ui.browser.content.set_visible_child_name("views");
@@ -474,7 +823,14 @@ pub(crate) fn attach_context_menu(ui: &Rc<Ui>, item: &gtk4::ListItem, anchor: &g
     gesture.connect_pressed(move |_, _, x, y| {
         if let Some(obj) = item.item().and_downcast::<BoxedAnyObject>() {
             let entry = obj.borrow::<DirEntry>().clone();
-            show_context_menu(&ui, &entry, &target, x, y);
+            // Right-clicking a row that is part of a multi-selection acts on the
+            // batch; right-clicking outside one acts on the row, as before.
+            let selected = selected_entries(&ui);
+            if selected.len() > 1 && selected.iter().any(|e| e.uid == entry.uid) {
+                show_bulk_context_menu(&ui, selected, &target, x, y);
+            } else {
+                show_context_menu(&ui, &entry, &target, x, y);
+            }
         }
     });
     anchor.add_controller(gesture);
@@ -588,6 +944,75 @@ pub(crate) fn show_context_menu(ui: &Rc<Ui>, entry: &DirEntry, anchor: &gtk4::Bo
     popover.popup();
 }
 
+/// The context menu for a multi-selection: the batch-capable actions only.
+/// Rename, Move, Share and the revision history all need a single subject, so
+/// they are simply absent here rather than offered and then refused.
+pub(crate) fn show_bulk_context_menu(
+    ui: &Rc<Ui>,
+    entries: Vec<DirEntry>,
+    anchor: &gtk4::Box,
+    x: f64,
+    y: f64,
+) {
+    let menu = gtk4::Box::new(gtk4::Orientation::Vertical, 0);
+    let popover = gtk4::Popover::builder()
+        .has_arrow(false)
+        .position(gtk4::PositionType::Bottom)
+        .pointing_to(&gtk4::gdk::Rectangle::new(x as i32, y as i32, 1, 1))
+        .child(&menu)
+        .build();
+    popover.set_parent(anchor);
+    popover.connect_closed(|p| p.unparent());
+
+    let header = gtk4::Label::builder()
+        .label(format!("{} selected", entries.len()))
+        .halign(gtk4::Align::Start)
+        .build();
+    header.add_css_class("dim-label");
+    header.add_css_class("caption");
+    header.set_margin_top(6);
+    header.set_margin_bottom(4);
+    header.set_margin_start(10);
+    menu.append(&header);
+
+    let files_only = entries.iter().all(|e| !e.is_dir);
+    if files_only && entries.iter().any(|e| !e.pinned) {
+        let pin = menu_item("Keep offline", "starred-symbolic");
+        let ui_pin = ui.clone();
+        let batch = entries.clone();
+        let pop = popover.clone();
+        pin.connect_clicked(move |_| {
+            pop.popdown();
+            run_bulk_pin(&ui_pin, batch.clone(), true);
+        });
+        menu.append(&pin);
+    }
+    if files_only && entries.iter().any(|e| e.pinned) {
+        let unpin = menu_item("Remove offline copy", "non-starred-symbolic");
+        let ui_unpin = ui.clone();
+        let batch = entries.clone();
+        let pop = popover.clone();
+        unpin.connect_clicked(move |_| {
+            pop.popdown();
+            run_bulk_pin(&ui_unpin, batch.clone(), false);
+        });
+        menu.append(&unpin);
+    }
+
+    menu.append(&gtk4::Separator::new(gtk4::Orientation::Horizontal));
+
+    let trash = menu_item("Move to Trash", "user-trash-symbolic");
+    let ui_tr = ui.clone();
+    let pop = popover.clone();
+    trash.connect_clicked(move |_| {
+        pop.popdown();
+        prompt_delete_many(&ui_tr, entries.clone());
+    });
+    menu.append(&trash);
+
+    popover.popup();
+}
+
 /// A left-aligned, flat icon+label button for the context menu.
 pub(crate) fn menu_item(label: &str, icon: &str) -> gtk4::Button {
     let row = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
@@ -976,8 +1401,6 @@ pub(crate) fn prompt_move(ui: &Rc<Ui>, entry: &DirEntry) {
 /// Confirm and move the entry to Trash through the daemon.
 pub(crate) fn prompt_delete(ui: &Rc<Ui>, entry: &DirEntry) {
     let win = ui_window(ui);
-    let rel = entry_rel(ui, entry);
-    let name = entry.name.clone();
     let dialog = adw::AlertDialog::builder()
         .heading("Move to Trash")
         .body(format!("Move “{}” to Trash?", entry.name))
@@ -988,15 +1411,13 @@ pub(crate) fn prompt_delete(ui: &Rc<Ui>, entry: &DirEntry) {
     dialog.set_default_response(Some("cancel"));
     dialog.set_close_response("cancel");
 
+    // Routed through the batch path so a single trash gets the same Undo: one
+    // mis-click on one file is no less worth taking back than fifty.
+    let entry = entry.clone();
     let ui = ui.clone();
     dialog.connect_response(None, move |_, resp| {
         if resp == "trash" {
-            run_mutation(
-                &ui,
-                Request::Delete { path: rel.clone() },
-                format!("Moved “{name}” to Trash"),
-                "Couldn't move to Trash",
-            );
+            run_bulk_delete(&ui, vec![entry.clone()]);
         }
     });
     dialog.present(win.as_ref());
@@ -1346,6 +1767,7 @@ pub(crate) fn repaint_browser(ui: &Rc<Ui>, entries: &[DirEntry]) {
             "Upload a file or create a folder to get started.",
             false,
         );
+        ui.browser.empty_actions.set_visible(true);
         return;
     }
     browser_views(ui);

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

@@ -9,5 +9,6 @@ pub(crate) mod photos;
 pub(crate) mod shared;
 pub(crate) mod shared_by_me;
 pub(crate) mod status;
+pub(crate) mod takeout;
 pub(crate) mod trash;
 pub(crate) mod verify;

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

@@ -19,6 +19,12 @@ pub(crate) struct GalleryState {
     pub(crate) retry: gtk4::Button,
     pub(crate) more: gtk4::Button,
     pub(crate) upload: gtk4::Button,
+    /// Opens the Google Photos Takeout import chooser.
+    pub(crate) import: gtk4::Button,
+    /// Upload / Import offered on the *empty timeline* status page, so a fresh
+    /// account is a place to start rather than a dead end. Hidden on every other
+    /// status: a load error is not the moment to offer an upload.
+    pub(crate) empty_actions: gtk4::Box,
     /// "Photos", or the album's name while one is open.
     pub(crate) title: gtk4::Label,
     /// "1,204 photos" under the page title.
@@ -177,6 +183,10 @@ pub(crate) struct GalleryWidgets {
     pub(crate) scroll: gtk4::ScrolledWindow,
     pub(crate) retry: gtk4::Button,
     pub(crate) upload: gtk4::Button,
+    pub(crate) import: gtk4::Button,
+    pub(crate) empty_actions: gtk4::Box,
+    pub(crate) empty_upload: gtk4::Button,
+    pub(crate) empty_import: gtk4::Button,
     pub(crate) refresh: gtk4::Button,
     /// The Albums grid, its own status page and the stack between them, plus the
     /// Photos/Albums switcher and the back button out of an album.
@@ -227,10 +237,29 @@ pub(crate) fn build_gallery_page() -> (gtk4::Widget, GalleryWidgets) {
     retry.add_css_class("suggested-action");
     retry.set_visible(false);
 
+    // The empty-timeline state's two ways forward. `StatusPage` takes one child,
+    // so Retry and these share a box and each is shown only for its own state.
+    let empty_upload = gtk4::Button::builder().label("Upload photos").build();
+    empty_upload.add_css_class("pill");
+    empty_upload.add_css_class("suggested-action");
+    let empty_import = gtk4::Button::builder()
+        .label("Import from Google Photos")
+        .build();
+    empty_import.add_css_class("pill");
+    let empty_actions = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
+    empty_actions.set_halign(gtk4::Align::Center);
+    empty_actions.set_visible(false);
+    empty_actions.append(&empty_upload);
+    empty_actions.append(&empty_import);
+
+    let status_child = gtk4::Box::new(gtk4::Orientation::Vertical, 12);
+    status_child.append(&retry);
+    status_child.append(&empty_actions);
+
     let status = adw::StatusPage::builder()
         .icon_name("image-x-generic-symbolic")
         .vexpand(true)
-        .child(&retry)
+        .child(&status_child)
         .build();
     status.add_css_class("compact");
 
@@ -288,12 +317,23 @@ pub(crate) fn build_gallery_page() -> (gtk4::Widget, GalleryWidgets) {
         .build();
     upload.add_css_class("pill");
     upload.add_css_class("suggested-action");
+
+    // Importing an export is a rarer, heavier action than adding one photo, so
+    // it sits beside Upload as a plain button rather than a second accent one.
+    let import = gtk4::Button::builder()
+        .icon_name("folder-download-symbolic")
+        .tooltip_text("Import a Google Photos Takeout export")
+        .valign(gtk4::Align::Center)
+        .build();
+    import.add_css_class("flat");
+    import.add_css_class("circular");
     let refresh = refresh_button();
 
     let header_box = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
     header_box.append(&back);
     header_box.append(&titles);
     header_box.append(&refresh);
+    header_box.append(&import);
     header_box.append(&upload);
 
     // All / Photos / Videos / Raw filter. Linked toggles acting as one segmented
@@ -428,6 +468,10 @@ pub(crate) fn build_gallery_page() -> (gtk4::Widget, GalleryWidgets) {
             scroll,
             retry,
             upload,
+            import,
+            empty_actions,
+            empty_upload,
+            empty_import,
             refresh,
             tabs,
             favorites_btn,
@@ -554,6 +598,15 @@ pub(crate) fn thousands(n: usize) -> String {
 /// Wire the gallery: install the section factory, the zoom gestures, the pager
 /// and the upload button. Activating a thumbnail downloads the photo and opens it
 /// in the in-app lightbox.
+/// Wire the empty-timeline buttons. Upload re-fires the header's own Upload
+/// rather than duplicating its file-chooser, so the two can't drift apart.
+pub(crate) fn wire_gallery_empty(ui: &Rc<Ui>, upload: &gtk4::Button, import: &gtk4::Button) {
+    let ui_upload = ui.clone();
+    upload.connect_clicked(move |_| ui_upload.gallery.upload.emit_clicked());
+    let ui_import = ui.clone();
+    import.connect_clicked(move |_| ui_import.stack.set_visible_child_name("takeout"));
+}
+
 pub(crate) fn wire_gallery(ui: &Rc<Ui>, list: &gtk4::ListView, scroll: &gtk4::ScrolledWindow) {
     let factory = gtk4::SignalListItemFactory::new();
     factory.connect_setup(|_, item| {
@@ -729,6 +782,14 @@ pub(crate) fn wire_gallery(ui: &Rc<Ui>, list: &gtk4::ListView, scroll: &gtk4::Sc
         load_gallery(&ui_dates, false);
     });
 
+    // The import is a staged, hours-long migration, so the button hands over to
+    // the Import page rather than opening a file chooser here: the archives need
+    // reviewing before anything is sent, and the run needs somewhere to report.
+    let ui_import = ui.clone();
+    ui.gallery
+        .import
+        .connect_clicked(move |_| ui_import.stack.set_visible_child_name("takeout"));
+
     let ui_upload = ui.clone();
     ui.gallery.upload.connect_clicked(move |_| {
         let dialog = gtk4::FileDialog::builder()
@@ -1460,6 +1521,12 @@ pub(crate) fn load_gallery(ui: &Rc<Ui>, append: bool) {
                         )
                     };
                     gallery_status(&ui, "image-x-generic-symbolic", title, description, false);
+                    // Only the whole-timeline empty state: an empty *album* is
+                    // filled by adding existing photos to it, not by uploading
+                    // into it, so the buttons would point the wrong way.
+                    ui.gallery
+                        .empty_actions
+                        .set_visible(ui.gallery.album.borrow().is_none());
                     return;
                 }
                 ui.gallery.content.set_visible_child_name("timeline");
@@ -1502,6 +1569,9 @@ pub(crate) fn gallery_status(ui: &Rc<Ui>, icon: &str, title: &str, description:
     ui.gallery.status.set_title(title);
     ui.gallery.status.set_description(Some(description));
     ui.gallery.retry.set_visible(retry);
+    // Only the empty timeline offers a way to fill it; every other status turns
+    // those buttons back off.
+    ui.gallery.empty_actions.set_visible(false);
     ui.gallery.more.set_visible(false);
     ui.gallery.content.set_visible_child_name("status");
 }

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

@@ -37,7 +37,16 @@ pub(crate) struct StatusState {
     /// Set while a settings widget is being populated programmatically, so its
     /// change handler skips the IPC/systemd side effect.
     pub(crate) settings_suppress: Cell<bool>,
+    /// Pending debounce for the cache-budget editor. Each `+` click is a value
+    /// change, and firing a `SetCacheBudget` (and a toast) per click means a
+    /// stack of toasts and a series of caps the user never asked to apply — so
+    /// only the value they settle on is sent.
+    pub(crate) budget_source: RefCell<Option<glib::SourceId>>,
     pub(crate) pins_group: adw::PreferencesGroup,
+    /// Whether the pin list is showing every pin or only the first
+    /// [`PINS_COLLAPSED`]. A long pin list would otherwise push everything below
+    /// it — including the Developer group — off the end of the page.
+    pub(crate) pins_expanded: Cell<bool>,
     /// Rows currently shown under [`Self::pins_group`], retained so a refresh can
     /// diff against them and only rebuild when the pin set actually changes.
     pub(crate) pin_rows: RefCell<Vec<PinRow>>,
@@ -104,6 +113,8 @@ pub(crate) struct MainWidgets {
     /// which is where the folder is changed.
     pub(crate) mountpoint_row: adw::ActionRow,
     pub(crate) mountpoint_button: gtk4::Button,
+    /// Opens the Google Photos Takeout import page.
+    pub(crate) import_row: adw::ActionRow,
 }
 
 /// The main (logged-in) page: a libadwaita settings surface — account header,
@@ -233,6 +244,22 @@ pub(crate) fn build_main_page() -> (gtk4::Widget, MainWidgets) {
     mountpoint_row.add_suffix(&mountpoint_button);
     system_group.add(&mountpoint_row);
 
+    // Import: a one-off migration rather than a setting, so it is a doorway to
+    // its own page rather than controls inlined here — staging a set of archives
+    // and watching an hours-long upload needs the room.
+    let import_group = adw::PreferencesGroup::builder()
+        .title("Import")
+        .description("Bring a photo library from another service into Proton Photos.")
+        .build();
+    let import_row = adw::ActionRow::builder()
+        .title("Import from Google Photos")
+        .subtitle("Add a Google Takeout export to your timeline.")
+        .activatable(true)
+        .build();
+    import_row.add_prefix(&gtk4::Image::from_icon_name("folder-download-symbolic"));
+    import_row.add_suffix(&gtk4::Image::from_icon_name("go-next-symbolic"));
+    import_group.add(&import_row);
+
     // Pins group: filled in by refresh.
     let pins_group = adw::PreferencesGroup::builder()
         .title("Pinned files")
@@ -265,6 +292,7 @@ pub(crate) fn build_main_page() -> (gtk4::Widget, MainWidgets) {
     inner.append(&transfers_group);
     inner.append(&storage_group);
     inner.append(&system_group);
+    inner.append(&import_group);
     inner.append(&pins_group);
     inner.append(&dev_group);
 
@@ -292,10 +320,20 @@ pub(crate) fn build_main_page() -> (gtk4::Widget, MainWidgets) {
             purge_button,
             mountpoint_row,
             mountpoint_button,
+            import_row,
         },
     )
 }
 
+/// How many pins the Settings list shows before collapsing the rest behind a
+/// "Show all" row. Enough to recognise the list at a glance; short enough that
+/// the groups below it stay reachable.
+pub(crate) const PINS_COLLAPSED: usize = 6;
+
+/// How long the cache-budget editor waits after the last change before applying
+/// it, so a run of `+` clicks is one request rather than one per click.
+pub(crate) const BUDGET_DEBOUNCE: Duration = Duration::from_millis(600);
+
 /// Bytes per GiB, for the cache-budget editor's unit conversion.
 pub(crate) const GIB: f64 = 1024.0 * 1024.0 * 1024.0;
 
@@ -308,6 +346,7 @@ pub(crate) fn wire_settings(
     ui: &Rc<Ui>,
     purge_button: &gtk4::Button,
     mountpoint_button: &gtk4::Button,
+    import_row: &adw::ActionRow,
 ) {
     let config = ui.dirs.load_config();
 
@@ -329,13 +368,22 @@ pub(crate) fn wire_settings(
         if ui_budget.status.settings_suppress.get() {
             return;
         }
+        // Replace any pending apply, so only the value the user stops on is sent.
+        if let Some(src) = ui_budget.status.budget_source.borrow_mut().take() {
+            src.remove();
+        }
         let bytes = (row.value() * GIB).round() as u64;
-        settings_request(
-            &ui_budget,
-            Request::SetCacheBudget { bytes },
-            "Cache budget updated",
-            "Couldn't set cache budget",
-        );
+        let ui_fire = ui_budget.clone();
+        let src = glib::timeout_add_local_once(BUDGET_DEBOUNCE, move || {
+            ui_fire.status.budget_source.borrow_mut().take();
+            settings_request(
+                &ui_fire,
+                Request::SetCacheBudget { bytes },
+                "Cache budget updated",
+                "Couldn't set cache budget",
+            );
+        });
+        *ui_budget.status.budget_source.borrow_mut() = Some(src);
     });
 
     // Purge: confirm, then drop all unpinned cached content via the daemon.
@@ -382,6 +430,10 @@ pub(crate) fn wire_settings(
     // local path; this button is the way there.
     let ui_mp = ui.clone();
     mountpoint_button.connect_clicked(move |_| ui_mp.stack.set_visible_child_name("locations"));
+
+    // Import: a doorway, not a setting — everything about it lives on its page.
+    let ui_import = ui.clone();
+    import_row.connect_activated(move |_| ui_import.stack.set_visible_child_name("takeout"));
 }
 
 /// Run a settings control-socket round-trip (budget / purge) on a worker thread,
@@ -513,6 +565,12 @@ pub(crate) fn refresh(ui: &Rc<Ui>) {
     refresh_transfers(ui);
     // Both of these pages show work as it happens, so they follow the tick while
     // they are on screen. Every other page loads on navigation only.
+    // A Takeout import outlives the page that started it, so it is polled
+    // wherever the user has navigated to — otherwise leaving the page means
+    // never being told it finished.
+    if ui.stack.visible_child_name().as_deref() == Some("takeout") || ui.takeout.running.get() {
+        refresh_takeout(ui);
+    }
     match ui.stack.visible_child_name().as_deref() {
         Some("main") => refresh_quota(ui),
         Some("locations") => refresh_locations(ui),
@@ -653,6 +711,10 @@ pub(crate) fn repaint_transfers(ui: &Rc<Ui>, items: &[TransferItem], jobs: &[Job
     // count falling to zero is what "the sync finished" looks like from here.
     // Jobs are deliberately not counted — a bulk upload retires its scan job and
     // starts its upload job mid-flight, which is not a thing finishing.
+    // The Import page reads its progress off the same snapshot rather than
+    // polling the daemon a second time for numbers already on the wire.
+    takeout_progress(ui, jobs);
+
     let previous = ui.status.active_transfers.replace(items.len());
     if items.is_empty() && previous > 0 {
         let files = if previous == 1 {
@@ -808,11 +870,14 @@ pub(crate) fn refresh_status(ui: &Rc<Ui>) {
                     (used as f64 / budget as f64).min(1.0)
                 };
                 ui.status.cache_bar.set_fraction(fraction);
-                ui.status.cache_label.set_text(&format!(
-                    "{} of {} used",
-                    human_bytes(used),
-                    human_bytes(budget)
-                ));
+                // A 0 budget means *unlimited*, not a zero-byte cap — "of 0 B
+                // used" reads as a broken read-out, and there is no fraction to
+                // draw against no limit.
+                ui.status.cache_label.set_text(&if budget == 0 {
+                    format!("{} cached — no limit set", human_bytes(used))
+                } else {
+                    format!("{} of {} used", human_bytes(used), human_bytes(budget))
+                });
                 repaint_pins(&ui, &pins, true);
             }
             // Daemon unreachable (still starting, or down): report not-mounted and
@@ -865,7 +930,15 @@ pub(crate) fn repaint_pins(ui: &Rc<Ui>, pins: &[pdfs_core::cache::Pin], mounted:
         return;
     }
 
-    for pin in pins {
+    // Only the first page of pins is rendered; the rest sit behind the row
+    // below, so a device with hundreds of pins doesn't bury the groups after it.
+    let expanded = ui.status.pins_expanded.get();
+    let shown = if expanded {
+        pins.len()
+    } else {
+        pins.len().min(PINS_COLLAPSED)
+    };
+    for pin in &pins[..shown] {
         let name = Path::new(&pin.path)
             .file_name()
             .and_then(|n| n.to_str())
@@ -903,4 +976,37 @@ pub(crate) fn repaint_pins(ui: &Rc<Ui>, pins: &[pdfs_core::cache::Pin], mounted:
             unpin: Some(unpin),
         });
     }
+
+    if pins.len() > PINS_COLLAPSED {
+        let row = adw::ActionRow::builder()
+            .title(if expanded {
+                "Show fewer".to_string()
+            } else {
+                format!("Show all {} pinned files", pins.len())
+            })
+            .activatable(true)
+            .build();
+        row.add_suffix(&gtk4::Image::from_icon_name(if expanded {
+            "go-up-symbolic"
+        } else {
+            "go-down-symbolic"
+        }));
+        let ui_more = ui.clone();
+        row.connect_activated(move |_| {
+            ui_more
+                .status
+                .pins_expanded
+                .set(!ui_more.status.pins_expanded.get());
+            // The diff guard compares pin *paths*; the same paths render
+            // differently now, so the baseline has to be dropped for the next
+            // repaint to actually rebuild.
+            *ui_more.status.pins_state.borrow_mut() = None;
+            refresh(&ui_more);
+        });
+        ui.status.pins_group.add(&row);
+        ui.status
+            .pin_rows
+            .borrow_mut()
+            .push(PinRow { row, unpin: None });
+    }
 }

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

@@ -0,0 +1,779 @@
+//! The Import page: bringing a Google Photos **Takeout** export into Proton
+//! Photos.
+//!
+//! Reached from Settings → *Import from Google Photos* (and from the Gallery's
+//! import button), because it is a one-off migration rather than something the
+//! photo timeline does every day. It gets a page of its own instead of a dialog
+//! for two reasons: an export is a *set* of archives that has to be staged and
+//! checked before anything is sent, and the import that follows runs for hours,
+//! so its progress needs somewhere to live that the user can navigate away from
+//! and come back to.
+//!
+//! Archives arrive either by drag-and-drop onto the page or through the file
+//! chooser; both funnel into [`add_archives`], which is where the `.zip` filter
+//! and de-duplication live. Nothing is sent until the user presses Scan or
+//! Import — staging is local, so a mis-drop costs nothing.
+//!
+//! The daemon owns the run itself ([`Request::ImportTakeout`]): this page only
+//! stages paths, launches, polls [`Request::ImportStatus`] for the final report,
+//! and reads live progress off the import's job in the transfer snapshot the
+//! Settings tick already fetches (see [`takeout_progress`]).
+
+use crate::*;
+
+/// The title the daemon gives the import's job in [`Request::GetQueueStatus`].
+/// Matching on it is how this page borrows the progress the Settings tick is
+/// already polling instead of adding a second poll of its own.
+const IMPORT_JOB: &str = "Importing Google Photos";
+
+/// What the archive list says before anything is staged. `repaint_archives`
+/// swaps in the count and total once there is something to report, and swaps
+/// this back when the list is emptied again.
+/// Where the staged set is remembered between runs, under the app's state
+/// directory. Staging an export means picking dozens of files out of a file
+/// chooser; losing that to a window close (or a crash mid-import) and having to
+/// redo it is the kind of small cruelty that makes a migration not get finished.
+fn staged_path(ui: &Rc<Ui>) -> PathBuf {
+    ui.dirs.state_dir().join("takeout-staged.json")
+}
+
+/// Read the remembered set, dropping any archive that has since been moved or
+/// deleted — a stale path would only fail at launch, and silently is worse.
+fn load_staged(ui: &Rc<Ui>) -> Vec<PathBuf> {
+    let Ok(text) = std::fs::read_to_string(staged_path(ui)) else {
+        return Vec::new();
+    };
+    let paths: Vec<String> = serde_json::from_str(&text).unwrap_or_default();
+    paths
+        .into_iter()
+        .map(PathBuf::from)
+        .filter(|p| p.is_file())
+        .collect()
+}
+
+/// Remember the staged set. Best-effort: failing to write it costs the user a
+/// re-pick next time, which is not worth interrupting them over now.
+fn save_staged(ui: &Rc<Ui>) {
+    let paths: Vec<String> = ui
+        .takeout
+        .archives
+        .borrow()
+        .iter()
+        .map(|p| p.display().to_string())
+        .collect();
+    let path = staged_path(ui);
+    let written = serde_json::to_string(&paths)
+        .map_err(|e| e.to_string())
+        .and_then(|text| std::fs::write(&path, text).map_err(|e| e.to_string()));
+    if let Err(e) = written {
+        tracing::warn!("cannot remember staged Takeout archives: {e}");
+    }
+}
+
+const EMPTY_LIST_DESCRIPTION: &str = "Photos already in Proton Photos are matched by name and content and skipped, so \
+     re-running an interrupted import is safe.";
+
+pub(crate) struct TakeoutState {
+    /// Archives staged for this import, in the order they were added. Sent as
+    /// one set: Google splits an export across numbered zips and routinely puts
+    /// a photo in one part and its metadata sidecar in another, so a per-file
+    /// import would lose album titles and capture times.
+    pub(crate) archives: RefCell<Vec<PathBuf>>,
+    /// The staged-archive list and the rows currently rendered in it.
+    pub(crate) list_group: adw::PreferencesGroup,
+    pub(crate) rows: RefCell<Vec<adw::PreferencesRow>>,
+    /// The drop zone, whose `dropzone-active` class follows the drag.
+    pub(crate) dropzone: gtk4::Box,
+    pub(crate) scan_button: gtk4::Button,
+    pub(crate) import_button: gtk4::Button,
+    pub(crate) cancel_button: gtk4::Button,
+    pub(crate) clear_button: gtk4::Button,
+    /// Progress group, hidden unless an import is running.
+    pub(crate) progress_group: adw::PreferencesGroup,
+    pub(crate) progress_label: gtk4::Label,
+    pub(crate) progress_bar: gtk4::ProgressBar,
+    /// Report group for the last finished run, hidden until there is one.
+    pub(crate) summary_group: adw::PreferencesGroup,
+    pub(crate) summary_rows: RefCell<Vec<adw::ActionRow>>,
+    /// One [`Request::ImportStatus`] in flight at a time, so a wedged daemon
+    /// can't stack worker threads on the 2s tick.
+    pub(crate) inflight: Cell<bool>,
+    /// Whether the daemon reported an import running on the last poll.
+    pub(crate) running: Cell<bool>,
+    /// Whether the run in flight was launched as a dry run, so the report can
+    /// say "would upload" rather than claiming photos were sent. The daemon's
+    /// summary carries no such flag — it is the same shape either way.
+    pub(crate) dry_run: Cell<bool>,
+}
+
+/// Widgets the Import page hands back for wiring.
+pub(crate) struct TakeoutWidgets {
+    pub(crate) list_group: adw::PreferencesGroup,
+    pub(crate) dropzone: gtk4::Box,
+    /// The whole page, which is the drop target: a drag released anywhere on it
+    /// counts, not only inside the dashed rectangle.
+    pub(crate) page: gtk4::Widget,
+    pub(crate) choose_button: gtk4::Button,
+    pub(crate) scan_button: gtk4::Button,
+    pub(crate) import_button: gtk4::Button,
+    pub(crate) cancel_button: gtk4::Button,
+    pub(crate) clear_button: gtk4::Button,
+    pub(crate) back_button: gtk4::Button,
+    pub(crate) progress_group: adw::PreferencesGroup,
+    pub(crate) progress_label: gtk4::Label,
+    pub(crate) progress_bar: gtk4::ProgressBar,
+    pub(crate) summary_group: adw::PreferencesGroup,
+}
+
+pub(crate) fn build_takeout_page() -> (gtk4::Widget, TakeoutWidgets) {
+    // Header: a back button out to Settings, since this page is reached from
+    // there and has no sidebar row of its own to navigate back with.
+    let back_button = gtk4::Button::builder()
+        .icon_name("go-previous-symbolic")
+        .tooltip_text("Back to Settings")
+        .valign(gtk4::Align::Center)
+        .build();
+    back_button.add_css_class("flat");
+
+    let title = gtk4::Label::builder()
+        .label("Import from Google Photos")
+        .halign(gtk4::Align::Start)
+        .build();
+    title.add_css_class("title-2");
+    let subtitle = gtk4::Label::builder()
+        .label("Add a Google Takeout export to your Proton Photos timeline.")
+        .halign(gtk4::Align::Start)
+        .wrap(true)
+        .xalign(0.0)
+        .build();
+    subtitle.add_css_class("dim-label");
+
+    let titles = gtk4::Box::new(gtk4::Orientation::Vertical, 2);
+    titles.set_hexpand(true);
+    titles.append(&title);
+    titles.append(&subtitle);
+
+    let header = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
+    header.append(&back_button);
+    header.append(&titles);
+    let header_clamp = adw::Clamp::builder().child(&header).build();
+
+    // Drop zone. It is a hint, not the only way in — the button under it does
+    // the same thing for anyone not dragging, and the drop target covers the
+    // whole page so a drag released just outside the rectangle still lands.
+    let drop_icon = gtk4::Image::from_icon_name("folder-download-symbolic");
+    drop_icon.set_pixel_size(48);
+    drop_icon.add_css_class("dim-label");
+    let drop_title = gtk4::Label::builder()
+        .label("Drop your Takeout .zip files here")
+        .build();
+    drop_title.add_css_class("title-4");
+    let drop_hint = gtk4::Label::builder()
+        .label("Add every part of the export at once — a photo and its metadata often sit in different parts.")
+        .wrap(true)
+        .justify(gtk4::Justification::Center)
+        .max_width_chars(48)
+        .build();
+    drop_hint.add_css_class("dim-label");
+    let choose_button = gtk4::Button::builder()
+        .label("Choose files…")
+        .halign(gtk4::Align::Center)
+        .build();
+    choose_button.add_css_class("pill");
+
+    let dropzone = gtk4::Box::new(gtk4::Orientation::Vertical, 10);
+    dropzone.set_halign(gtk4::Align::Fill);
+    dropzone.add_css_class("dropzone");
+    dropzone.append(&drop_icon);
+    dropzone.append(&drop_title);
+    dropzone.append(&drop_hint);
+    dropzone.append(&choose_button);
+
+    // Staged archives. Filled by `repaint_archives`, which owns the description
+    // too (it becomes the count + total once there is something to count); the
+    // group carries a placeholder row while empty so it never renders as a bare
+    // title.
+    let list_group = adw::PreferencesGroup::builder()
+        .title("Archives to import")
+        .description(EMPTY_LIST_DESCRIPTION)
+        .build();
+
+    let clear_button = gtk4::Button::builder()
+        .label("Clear")
+        .tooltip_text("Remove every staged archive")
+        .build();
+    clear_button.add_css_class("flat");
+
+    // Actions. Scan is a dry run: it reads the archives' directories and reports
+    // what an import *would* do, without uploading a byte. It is offered first
+    // because the import behind it is hours long and hard to take back.
+    let scan_button = gtk4::Button::builder()
+        .label("Scan")
+        .tooltip_text("Check the archives and report what would be imported, without uploading")
+        .build();
+    scan_button.add_css_class("pill");
+    let import_button = gtk4::Button::builder().label("Import").build();
+    import_button.add_css_class("pill");
+    import_button.add_css_class("suggested-action");
+    let cancel_button = gtk4::Button::builder()
+        .label("Stop import")
+        .tooltip_text("Finish the photo on the wire, file what was uploaded, then stop")
+        .build();
+    cancel_button.add_css_class("pill");
+    cancel_button.add_css_class("destructive-action");
+    cancel_button.set_visible(false);
+
+    // Clear sits apart from the launch buttons, on the other end of the row: it
+    // undoes staging, and putting it next to Import invites the wrong click.
+    let actions = gtk4::Box::new(gtk4::Orientation::Horizontal, 8);
+    let spacer = gtk4::Box::new(gtk4::Orientation::Horizontal, 0);
+    spacer.set_hexpand(true);
+    actions.append(&clear_button);
+    actions.append(&spacer);
+    actions.append(&cancel_button);
+    actions.append(&scan_button);
+    actions.append(&import_button);
+
+    // Progress: the import's job from the transfer snapshot, so this page shows
+    // the same numbers the Settings Activity list does.
+    let progress_group = adw::PreferencesGroup::builder()
+        .title("Import in progress")
+        .visible(false)
+        .build();
+    let progress_box = gtk4::Box::new(gtk4::Orientation::Vertical, 6);
+    progress_box.set_margin_top(8);
+    progress_box.set_margin_bottom(8);
+    let progress_label = gtk4::Label::builder().halign(gtk4::Align::Start).build();
+    progress_label.add_css_class("dim-label");
+    let progress_bar = gtk4::ProgressBar::new();
+    progress_box.append(&progress_label);
+    progress_box.append(&progress_bar);
+    progress_group.add(
+        &adw::PreferencesRow::builder()
+            .activatable(false)
+            .child(&progress_box)
+            .build(),
+    );
+
+    // Report for the last finished run, kept on screen after it ends: an import
+    // outlives the window being on this page, and "what happened" is the whole
+    // reason to come back to it.
+    let summary_group = adw::PreferencesGroup::builder()
+        .title("Last import")
+        .visible(false)
+        .build();
+
+    let groups = gtk4::Box::new(gtk4::Orientation::Vertical, 18);
+    groups.append(&dropzone);
+    groups.append(&list_group);
+    groups.append(&actions);
+    groups.append(&progress_group);
+    groups.append(&summary_group);
+    let clamp = adw::Clamp::builder()
+        .maximum_size(640)
+        .child(&groups)
+        .build();
+    let scroll = gtk4::ScrolledWindow::builder()
+        .vexpand(true)
+        .hscrollbar_policy(gtk4::PolicyType::Never)
+        .child(&clamp)
+        .build();
+
+    let page = gtk4::Box::new(gtk4::Orientation::Vertical, 12);
+    page.set_margin_top(18);
+    page.set_margin_bottom(18);
+    page.set_margin_start(18);
+    page.set_margin_end(18);
+    page.append(&header_clamp);
+    page.append(&scroll);
+
+    let widgets = TakeoutWidgets {
+        list_group: list_group.clone(),
+        dropzone: dropzone.clone(),
+        page: page.clone().upcast(),
+        choose_button,
+        scan_button: scan_button.clone(),
+        import_button: import_button.clone(),
+        cancel_button: cancel_button.clone(),
+        clear_button,
+        back_button,
+        progress_group: progress_group.clone(),
+        progress_label: progress_label.clone(),
+        progress_bar: progress_bar.clone(),
+        summary_group: summary_group.clone(),
+    };
+    (page.upcast(), widgets)
+}
+
+pub(crate) fn wire_takeout(ui: &Rc<Ui>, widgets: &TakeoutWidgets) {
+    // Drag-and-drop. The target sits on the whole page rather than the dashed
+    // rectangle, so a drag released anywhere counts; the rectangle only lights
+    // up to say where the drop is understood.
+    let target = gtk4::DropTarget::new(
+        gtk4::gdk::FileList::static_type(),
+        gtk4::gdk::DragAction::COPY,
+    );
+    let ui_enter = ui.clone();
+    target.connect_enter(move |_, _, _| {
+        ui_enter.takeout.dropzone.add_css_class("dropzone-active");
+        gtk4::gdk::DragAction::COPY
+    });
+    let ui_leave = ui.clone();
+    target.connect_leave(move |_| {
+        ui_leave
+            .takeout
+            .dropzone
+            .remove_css_class("dropzone-active");
+    });
+    let ui_drop = ui.clone();
+    target.connect_drop(move |_, value, _, _| {
+        ui_drop.takeout.dropzone.remove_css_class("dropzone-active");
+        let Ok(files) = value.get::<gtk4::gdk::FileList>() else {
+            return false;
+        };
+        let paths: Vec<PathBuf> = files.files().iter().filter_map(|f| f.path()).collect();
+        add_archives(&ui_drop, paths);
+        true
+    });
+    widgets.page.add_controller(target);
+
+    let ui_choose = ui.clone();
+    widgets.choose_button.connect_clicked(move |_| {
+        // Multi-select on purpose: the whole export goes in one request.
+        let dialog = gtk4::FileDialog::builder()
+            .title("Select your Google Takeout archives")
+            .build();
+        let filter = gtk4::FileFilter::new();
+        filter.set_name(Some("Takeout archives"));
+        filter.add_pattern("*.zip");
+        let filters = gio::ListStore::new::<gtk4::FileFilter>();
+        filters.append(&filter);
+        dialog.set_filters(Some(&filters));
+
+        let ui = ui_choose.clone();
+        dialog.open_multiple(
+            ui_window(&ui_choose).as_ref(),
+            gio::Cancellable::NONE,
+            move |res| {
+                let Ok(files) = res else { return };
+                let paths: Vec<PathBuf> = (0..files.n_items())
+                    .filter_map(|index| files.item(index))
+                    .filter_map(|object| object.downcast::<gio::File>().ok())
+                    .filter_map(|file| file.path())
+                    .collect();
+                add_archives(&ui, paths);
+            },
+        );
+    });
+
+    let ui_clear = ui.clone();
+    widgets.clear_button.connect_clicked(move |_| {
+        ui_clear.takeout.archives.borrow_mut().clear();
+        repaint_archives(&ui_clear);
+    });
+
+    let ui_scan = ui.clone();
+    widgets
+        .scan_button
+        .connect_clicked(move |_| start_import(&ui_scan, true));
+
+    // The import itself is confirmed: it uploads a whole photo library, which is
+    // hours of bandwidth and a large change to the account's timeline.
+    let ui_import = ui.clone();
+    widgets.import_button.connect_clicked(move |_| {
+        let count = ui_import.takeout.archives.borrow().len();
+        let ui = ui_import.clone();
+        let dialog = adw::AlertDialog::builder()
+            .heading("Import this export?")
+            .body(format!(
+                "{count} archive(s) will be uploaded to Proton Photos, creating albums as they \
+                 appear in the export. This can take hours; you can stop it at any point and \
+                 what has been uploaded stays. Photos you already have are skipped.",
+            ))
+            .build();
+        dialog.add_response("cancel", "Cancel");
+        dialog.add_response("import", "Import");
+        dialog.set_response_appearance("import", adw::ResponseAppearance::Suggested);
+        dialog.set_default_response(Some("cancel"));
+        dialog.set_close_response("cancel");
+        dialog.connect_response(None, move |_, resp| {
+            if resp == "import" {
+                start_import(&ui, false);
+            }
+        });
+        dialog.present(ui_window(&ui_import).as_ref());
+    });
+
+    let ui_cancel = ui.clone();
+    widgets.cancel_button.connect_clicked(move |_| {
+        let ui = ui_cancel.clone();
+        ui.busy_begin();
+        let rx = spawn_request(ui.dirs.control_socket(), Request::CancelImport);
+        glib::spawn_future_local(async move {
+            let result = rx.recv().await;
+            ui.busy_end();
+            match result {
+                Ok(Ok(Response::Ok { .. })) => toast(&ui, "Stopping the import…"),
+                Ok(Ok(Response::Error { message, kind })) => {
+                    toast_failure(&ui, "Couldn't stop the import", &message, kind);
+                }
+                _ => toast_error(
+                    &ui,
+                    "Couldn't stop the import",
+                    "The mount service didn't respond.",
+                ),
+            }
+        });
+    });
+
+    let ui_back = ui.clone();
+    widgets
+        .back_button
+        .connect_clicked(move |_| ui_back.stack.set_visible_child_name("main"));
+
+    // Restore whatever was staged when the window last closed, before the first
+    // paint, so the page comes up as the user left it.
+    *ui.takeout.archives.borrow_mut() = load_staged(ui);
+    repaint_archives(ui);
+}
+
+/// Stage `paths`, keeping only `.zip` files and skipping ones already staged.
+///
+/// Both the chooser and the drop target land here, so the filter is stated once.
+/// A dropped folder (an already-extracted export) is rejected rather than walked:
+/// the scan reads the archives' central directories, and an extracted tree has
+/// none — silently importing half of it would be worse than saying no.
+pub(crate) fn add_archives(ui: &Rc<Ui>, paths: Vec<PathBuf>) {
+    let mut added = 0usize;
+    let mut rejected = 0usize;
+    {
+        let mut staged = ui.takeout.archives.borrow_mut();
+        for path in paths {
+            let is_zip = path
+                .extension()
+                .is_some_and(|ext| ext.eq_ignore_ascii_case("zip"));
+            if !is_zip || !path.is_file() {
+                rejected += 1;
+                continue;
+            }
+            if staged.contains(&path) {
+                continue;
+            }
+            staged.push(path);
+            added += 1;
+        }
+        // Numbered parts drop in whatever order the file manager hands them
+        // over; sorting keeps the list readable and the request stable.
+        staged.sort();
+    }
+    repaint_archives(ui);
+    if rejected > 0 {
+        toast(
+            ui,
+            "Only Takeout .zip files can be imported — extracted folders aren't supported.",
+        );
+    } else if added > 0 {
+        toast(ui, &format!("Added {added} archive(s)"));
+    }
+}
+
+/// Rebuild the staged-archive list and re-derive which actions are available.
+pub(crate) fn repaint_archives(ui: &Rc<Ui>) {
+    for row in ui.takeout.rows.borrow_mut().drain(..) {
+        ui.takeout.list_group.remove(&row);
+    }
+
+    let staged = ui.takeout.archives.borrow().clone();
+    let mut rows: Vec<adw::PreferencesRow> = Vec::new();
+    if staged.is_empty() {
+        ui.takeout
+            .list_group
+            .set_description(Some(EMPTY_LIST_DESCRIPTION));
+        let row = dim_row("No archives added yet.");
+        ui.takeout.list_group.add(&row);
+        rows.push(row.upcast());
+    } else {
+        let mut total = 0u64;
+        for path in &staged {
+            let size = std::fs::metadata(path).map(|m| m.len()).unwrap_or(0);
+            total += size;
+            let row = adw::ActionRow::builder()
+                .title(
+                    path.file_name()
+                        .map(|n| n.to_string_lossy().to_string())
+                        .unwrap_or_else(|| path.display().to_string()),
+                )
+                .subtitle(human_bytes(size))
+                .build();
+            let remove = gtk4::Button::builder()
+                .icon_name("edit-delete-symbolic")
+                .tooltip_text("Remove from this import")
+                .valign(gtk4::Align::Center)
+                .build();
+            remove.add_css_class("flat");
+            let ui_remove = ui.clone();
+            let target = path.clone();
+            remove.connect_clicked(move |_| {
+                ui_remove
+                    .takeout
+                    .archives
+                    .borrow_mut()
+                    .retain(|p| *p != target);
+                repaint_archives(&ui_remove);
+            });
+            row.add_suffix(&remove);
+            ui.takeout.list_group.add(&row);
+            rows.push(row.upcast());
+        }
+        ui.takeout.list_group.set_description(Some(&format!(
+            "{} archive(s), {} in total. {EMPTY_LIST_DESCRIPTION}",
+            staged.len(),
+            human_bytes(total)
+        )));
+    }
+    *ui.takeout.rows.borrow_mut() = rows;
+
+    save_staged(ui);
+    sync_takeout_actions(ui);
+}
+
+/// Enable exactly the actions that make sense right now: nothing to launch
+/// without archives, nothing to launch while a run is in flight, and Stop only
+/// while there is something to stop.
+fn sync_takeout_actions(ui: &Rc<Ui>) {
+    let has_files = !ui.takeout.archives.borrow().is_empty();
+    let running = ui.takeout.running.get();
+    ui.takeout.scan_button.set_sensitive(has_files && !running);
+    ui.takeout
+        .import_button
+        .set_sensitive(has_files && !running);
+    ui.takeout.clear_button.set_sensitive(has_files && !running);
+    ui.takeout.cancel_button.set_visible(running);
+}
+
+/// Hand the staged set to the daemon. It acks immediately and works in the
+/// background — an export is far past any socket timeout — so success here means
+/// "started", and the page switches over to reporting progress.
+fn start_import(ui: &Rc<Ui>, dry_run: bool) {
+    let archives: Vec<String> = ui
+        .takeout
+        .archives
+        .borrow()
+        .iter()
+        .map(|p| p.display().to_string())
+        .collect();
+    if archives.is_empty() {
+        return;
+    }
+
+    ui.takeout.dry_run.set(dry_run);
+    ui.busy_begin();
+    let rx = spawn_request(
+        ui.dirs.control_socket(),
+        Request::ImportTakeout { archives, dry_run },
+    );
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let result = rx.recv().await;
+        ui.busy_end();
+        match result {
+            Ok(Ok(Response::Ok { .. })) => {
+                ui.takeout.running.set(true);
+                ui.takeout.summary_group.set_visible(false);
+                ui.takeout.progress_group.set_visible(true);
+                ui.takeout.progress_bar.set_fraction(0.0);
+                ui.takeout.progress_label.set_text(if dry_run {
+                    "Reading archives…"
+                } else {
+                    "Starting import…"
+                });
+                sync_takeout_actions(&ui);
+                toast(
+                    &ui,
+                    if dry_run {
+                        "Scanning the export…"
+                    } else {
+                        "Import started — you can leave this page, it keeps running."
+                    },
+                );
+            }
+            Ok(Ok(Response::Error { message, kind })) => {
+                toast_failure(&ui, "Couldn't start the import", &message, kind);
+            }
+            _ => toast_error(
+                &ui,
+                "Couldn't start the import",
+                "The mount service didn't respond.",
+            ),
+        }
+    });
+}
+
+/// Poll the daemon for the import's state while the page is on screen, and paint
+/// the report once a run has finished. Cheap and inflight-guarded, like the other
+/// tick polls.
+pub(crate) fn refresh_takeout(ui: &Rc<Ui>) {
+    if ui.takeout.inflight.get() {
+        return;
+    }
+    ui.takeout.inflight.set(true);
+    let rx = spawn_request(ui.dirs.control_socket(), Request::ImportStatus);
+    let ui = ui.clone();
+    glib::spawn_future_local(async move {
+        let result = rx.recv().await;
+        ui.takeout.inflight.set(false);
+        let Ok(Ok(Response::ImportStatus { running, summary })) = result else {
+            return;
+        };
+        let was_running = ui.takeout.running.replace(running);
+        if running {
+            ui.takeout.progress_group.set_visible(true);
+        } else {
+            ui.takeout.progress_group.set_visible(false);
+            // An import runs for hours, so its ending is announced rather than
+            // left to be discovered: a toast for whoever is looking at the
+            // window, and a desktop notification for whoever is not.
+            if was_running {
+                let dry = ui.takeout.dry_run.get();
+                let headline = if dry {
+                    "Scan finished"
+                } else {
+                    "Import finished"
+                };
+                toast(&ui, headline);
+                if !dry {
+                    let body = match &summary {
+                        Some(s) if s.failed > 0 => {
+                            format!("{} photos added, {} failed.", s.uploaded, s.failed)
+                        }
+                        Some(s) if s.cancelled => {
+                            format!("Stopped after {} photos.", s.uploaded)
+                        }
+                        Some(s) => format!("{} photos added to Proton Photos.", s.uploaded),
+                        None => "The Google Photos import has finished.".to_string(),
+                    };
+                    notify("takeout-import", headline, &body);
+                }
+            }
+        }
+        if was_running != running {
+            sync_takeout_actions(&ui);
+        }
+        match summary {
+            Some(summary) => repaint_summary(&ui, &summary),
+            None => ui.takeout.summary_group.set_visible(false),
+        }
+    });
+}
+
+/// Paint the last run's report.
+fn repaint_summary(ui: &Rc<Ui>, summary: &ImportSummary) {
+    for row in ui.takeout.summary_rows.borrow_mut().drain(..) {
+        ui.takeout.summary_group.remove(&row);
+    }
+    let dry = ui.takeout.dry_run.get();
+    ui.takeout
+        .summary_group
+        .set_title(if dry { "Scan result" } else { "Last import" });
+    ui.takeout.summary_group.set_description(Some(if dry {
+        "Nothing was uploaded — this is what an import would do."
+    } else if summary.cancelled {
+        "Stopped early. Everything uploaded so far is in your timeline; run it again to \
+         continue where it left off."
+    } else {
+        "Finished."
+    }));
+
+    // Only lines that carry information: a run with no failures should not have
+    // to show a "0 failed" row for the user to read past.
+    let mut lines: Vec<(String, String)> = vec![
+        ("Photos in the export".into(), summary.found.to_string()),
+        (
+            if dry { "Would upload" } else { "Uploaded" }.into(),
+            summary.uploaded.to_string(),
+        ),
+    ];
+    if summary.duplicates > 0 {
+        lines.push((
+            "Already in Proton Photos".into(),
+            summary.duplicates.to_string(),
+        ));
+    }
+    if summary.albums_created > 0 {
+        lines.push((
+            if dry {
+                "Albums to create"
+            } else {
+                "Albums created"
+            }
+            .into(),
+            summary.albums_created.to_string(),
+        ));
+    }
+    if summary.album_links > 0 {
+        lines.push((
+            "Photos filed into albums".into(),
+            summary.album_links.to_string(),
+        ));
+    }
+    if summary.skipped_trashed > 0 {
+        lines.push((
+            "Skipped (in Google's trash)".into(),
+            summary.skipped_trashed.to_string(),
+        ));
+    }
+    if summary.bytes > 0 {
+        lines.push((
+            if dry {
+                "Data to upload"
+            } else {
+                "Data uploaded"
+            }
+            .into(),
+            human_bytes(summary.bytes),
+        ));
+    }
+    if summary.failed > 0 {
+        lines.push(("Failed".into(), summary.failed.to_string()));
+    }
+
+    let mut rows = Vec::new();
+    for (title, value) in lines {
+        let row = adw::ActionRow::builder()
+            .title(title)
+            .subtitle(value)
+            .build();
+        row.add_css_class("property");
+        ui.takeout.summary_group.add(&row);
+        rows.push(row);
+    }
+    *ui.takeout.summary_rows.borrow_mut() = rows;
+    ui.takeout.summary_group.set_visible(true);
+}
+
+/// Paint the import's progress from the transfer snapshot the Settings tick
+/// already fetched, so this page costs no extra poll. A job with no known total
+/// pulses instead of showing a fraction, the same as the Activity list.
+pub(crate) fn takeout_progress(ui: &Rc<Ui>, jobs: &[JobItem]) {
+    let Some(job) = jobs.iter().find(|job| job.title == IMPORT_JOB) else {
+        return;
+    };
+    ui.takeout.progress_group.set_visible(true);
+    if job.total > 0 {
+        ui.takeout
+            .progress_bar
+            .set_fraction((job.done as f64 / job.total as f64).min(1.0));
+        ui.takeout
+            .progress_label
+            .set_text(&format!("{} of {} — {}", job.done, job.total, job.detail));
+    } else {
+        ui.takeout.progress_bar.pulse();
+        ui.takeout
+            .progress_label
+            .set_text(if job.detail.is_empty() {
+                "Working…"
+            } else {
+                &job.detail
+            });
+    }
+}

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

@@ -11,8 +11,8 @@ pub(crate) struct DetailsState {
     pub(crate) details_suppress: Cell<bool>,
     /// The grid's and list's selection models. Both wrap the one browser model, so
     /// a selection in either drives the details pane.
-    pub(crate) grid_selection: gtk4::SingleSelection,
-    pub(crate) list_selection: gtk4::SingleSelection,
+    pub(crate) grid_selection: gtk4::MultiSelection,
+    pub(crate) list_selection: gtk4::MultiSelection,
 }
 
 /// The widgets in the browser's details pane that a selection repaints.
@@ -158,24 +158,22 @@ pub(crate) fn wire_details(ui: &Rc<Ui>) {
         ui.details.list_selection.clone(),
     ] {
         let ui_sel = ui.clone();
-        selection.connect_selection_changed(move |sel, _, _| {
-            match entry_at(sel.model().as_ref(), sel.selected()) {
-                Some(entry) => show_details(&ui_sel, &entry),
-                None => hide_details(&ui_sel),
+        selection.connect_selection_changed(move |_, _, _| {
+            // The details pane describes *one* entry. A batch is the bulk bar's
+            // business, so the pane steps aside rather than picking a member of
+            // the selection to speak for the rest.
+            let entries = selected_entries(&ui_sel);
+            match entries.as_slice() {
+                [entry] => show_details(&ui_sel, entry),
+                _ => hide_details(&ui_sel),
             }
+            sync_bulk_bar(&ui_sel);
         });
     }
 
     let ui_close = ui.clone();
     ui.details.details.close_button.connect_clicked(move |_| {
-        ui_close
-            .details
-            .grid_selection
-            .set_selected(gtk4::INVALID_LIST_POSITION);
-        ui_close
-            .details
-            .list_selection
-            .set_selected(gtk4::INVALID_LIST_POSITION);
+        clear_selection(&ui_close);
         hide_details(&ui_close);
     });
 
@@ -289,8 +287,9 @@ pub(crate) fn hide_details(ui: &Rc<Ui>) {
     *ui.details.details_entry.borrow_mut() = None;
 }
 
-/// The entry highlighted in whichever browser view is on screen, if any. Backs the
-/// F2 / Delete shortcuts.
+/// The single entry the details pane is showing, if any. Backs the actions that
+/// only make sense on one entry (rename, versions); the batch-capable ones ask
+/// [`selected_entries`] instead.
 pub(crate) fn selected_entry(ui: &Rc<Ui>) -> Option<DirEntry> {
     ui.details.details_entry.borrow().clone()
 }

crates/pdfs-gui/src/dmenu.rs

@@ -130,7 +130,7 @@ fn pins(socket: &Path) -> Result<Vec<Hit>, String> {
             Hit::Drive(SearchHit {
                 name: file_name(&pin.path),
                 path: pin.path,
-                is_dir: pin.recursive,
+                is_dir: pin.is_dir.unwrap_or(pin.recursive),
                 size: 0,
                 modified: 0,
                 pinned: true,

crates/pdfs-gui/src/prompt.rs

@@ -147,29 +147,26 @@ impl Hit {
     }
 
     /// The dimmed second line: the containing folder, as the user thinks of it.
+    ///
+    /// A Drive hit is only "My files" when it really sits in the primary mount.
+    /// A node inside a device folder resolves to a path on this machine
+    /// (`~/Downloads/…`) — the daemon has already worked that out in
+    /// `mounted_path`, and saying "My files / Downloads" for it names a folder
+    /// the user cannot find and does not match where activating the row opens.
     fn location(&self) -> String {
         match self {
-            Hit::Drive(h) => {
-                let parent = parent_of(&h.path);
-                if parent.is_empty() {
-                    "My files".to_string()
-                } else {
-                    format!("My files / {}", parent.replace('/', " / "))
+            Hit::Drive(h) => match h.mounted_path.as_deref() {
+                Some(mounted) => home_relative(&parent_of(mounted)),
+                None => {
+                    let parent = parent_of(&h.path);
+                    if parent.is_empty() {
+                        "My files".to_string()
+                    } else {
+                        format!("My files / {}", parent.replace('/', " / "))
+                    }
                 }
-            }
-            Hit::Local(h) => {
-                let parent = parent_of(&h.path);
-                match dirs_home().and_then(|home| {
-                    Path::new(&parent)
-                        .strip_prefix(&home)
-                        .ok()
-                        .map(|rel| rel.display().to_string())
-                }) {
-                    Some(rel) if rel.is_empty() => "Home".to_string(),
-                    Some(rel) => format!("Home / {}", rel.replace('/', " / ")),
-                    None => parent,
-                }
-            }
+            },
+            Hit::Local(h) => home_relative(&parent_of(&h.path)),
         }
     }
 
@@ -869,7 +866,7 @@ impl Ui {
                     .map(|pin| SearchHit {
                         name: file_name(&pin.path),
                         path: pin.path,
-                        is_dir: pin.recursive,
+                        is_dir: pin.is_dir.unwrap_or(pin.recursive),
                         size: 0,
                         modified: 0,
                         pinned: true,
@@ -1358,6 +1355,21 @@ fn file_name(path: &str) -> String {
         .to_string()
 }
 
+/// An absolute directory path as "Home / …", falling back to the path itself
+/// for anything outside the home directory.
+fn home_relative(parent: &str) -> String {
+    match dirs_home().and_then(|home| {
+        Path::new(parent)
+            .strip_prefix(&home)
+            .ok()
+            .map(|rel| rel.display().to_string())
+    }) {
+        Some(rel) if rel.is_empty() => "Home".to_string(),
+        Some(rel) => format!("Home / {}", rel.replace('/', " / ")),
+        None => parent.to_string(),
+    }
+}
+
 fn parent_of(path: &str) -> String {
     Path::new(path)
         .parent()

docs/ARCHITECTURE.md

@@ -153,8 +153,9 @@ Because Proton Drive does not support partial byte writes, modified files must b
 2. **Close/Release (`queue_revision`):** When the application closes the file descriptor, the daemon:
    - Fetches any untouched gaps from the remote base file to compile the full file.
    - Durably publishes the scratch data and authored-range sidecar into `staging` under a `{uid}-{millis}-{counter}` name. Temporary data and metadata are synced before atomic rename, and their directory is synced before the source is removed.
-   - Transactionally queues or supersedes a pending database operation (`PendingOp`), so insertion failure cannot erase the previously acknowledged upload. For `OP_REVISION` ops, execution is debounced by 2 seconds (`DRAIN_REVISION_DEBOUNCE = 2s`) to give rapid follow-up writes (e.g. `aria2c` preallocation followed by writing) time to supersede the staged blob before network transmission.
-3. **Async Drain Thread (`run_pending_drain`):** The background drain worker picks up the database operations queue, handles revision uploads, resolves conflicts, and cleans up staging files. Upon landing a revision upload (`refresh_after_upload`), it rebaselines both still-queued ops (`rebaseline_pending`) and open write handles targeting the same node to prevent false self-conflict copies on subsequent writes.
+   - Transactionally queues or supersedes a pending database operation (`PendingOp`), so insertion failure cannot erase the previously acknowledged upload. For `OP_REVISION` ops, execution is debounced to give rapid follow-up writes (e.g. `aria2c` preallocation followed by writing) time to supersede the staged blob before network transmission. The debounce is adaptive (`Core::revision_debounce`): it starts at `DRAIN_REVISION_DEBOUNCE = 2s` and, once a node has been uploaded, widens toward how long that upload actually took, bounded by `DRAIN_REVISION_DEBOUNCE_MAX = 60s`. A file saved faster than it can be sent therefore supersedes in the queue rather than mid-upload.
+   - Signals `Core::cancel_upload` for the node before touching the queue. A drain worker may already be reading the blob this write supersedes; the flag is read by the upload's `CountingReader`, which refuses the SDK's next block. `queue_trash` and `discard_queued_ops` do the same, because they unlink the blob outright.
+3. **Async Drain Threads (`run_pending_drain`):** `DRAIN_WORKERS = 3` background workers share the operations queue. They pick work up through `Db::claim_next_due_op`, which marks the row `claimed_at` in the same transaction that selects it and excludes any op whose uid another worker already holds — ordering only has to hold *per node*, and that exclusion is what guarantees it. Worker 0 additionally runs the queue's idle chores (LRU touch flush, `recover_fsynced_writes`). A claim is process-local state: the single-writer `flock` means one found at open belongs to a crashed run, and `Db::clear_op_claims` drops the lot so those ops are not invisible forever. Each worker handles revision uploads, resolves conflicts, and cleans up staging files. Upon landing a revision upload (`refresh_after_upload`), it rebaselines both still-queued ops (`rebaseline_pending`) and open write handles targeting the same node to prevent false self-conflict copies on subsequent writes.
 
 ```mermaid
 sequenceDiagram

docs/CHANGELOG.md

@@ -0,0 +1,517 @@
+# Changelog
+
+All notable changes to the Linux client since the 1.0.0 release. Format follows
+[Keep a Changelog](https://keepachangelog.com/1.1.0/); versions follow semver, and every
+release is tagged `vX.Y.Z` with `Cargo.toml` and `packaging/PKGBUILD` in agreement.
+
+`Schema:` lines record the SQLite `SCHEMA_VERSION` (`pdfs-core/src/db/migrations.rs`) a
+release ships. Migrations are forward-only — a database written by a newer client is a hard
+refuse-to-open, not a downgrade, so rolling back a release means restoring the cache from
+scratch (user data in `staging/` and `recovery/` is never touched by this).
+
+## [1.9.0] — 2026-08-18
+
+Google Photos import, and a pass over the desktop app's interaction gaps. No schema change.
+Schema: **28**. Builds against the published `proton-sdk` / `proton-drive-rs` **0.6.1** — the album
+writes this release needs are in the registry crates, so the local `[patch.crates-io]` shim the
+feature was developed against is gone and no local path dependency remains.
+
+### Added
+- **Import a Google Photos Takeout export into Proton Photos** — `pdfs import-google-photos
+  takeout-*.zip` (add `--dry-run` to see what it would do, `--wait` to follow it), or the import
+  button in the Photos header, which multi-selects the export's zips. Albums in the export are
+  recreated as Proton albums and their photos filed into them; year folders and `Archive/` import
+  into the timeline; `Trash/` is skipped. Capture times and favourites come from Google's per-photo
+  JSON sidecars, including the truncated and `(N)`-swapped sidecar names Google produces.
+- Photos already on the account are **not re-uploaded**: the import asks the photos volume which of
+  the export's names exist (batched, 150 per request), reads and SHA-1s only those files, and skips
+  the ones whose content digest matches too — Proton's own duplicate rule. A library already partly
+  synced by Proton Photos on a phone therefore imports only what is missing, and an interrupted
+  import resumes by being run again. Google keeps a full copy of a photo in every album folder it
+  appears in; those fold into one upload that joins several albums.
+- The import streams each photo straight out of its zip, so an export needs no scratch space to
+  unpack into, and reports as a job in `pdfs transfers` and the GUI's activity view. `pdfs
+  import-status` shows the counts, `pdfs cancel-import` stops it — a cancelled run still files what
+  it uploaded into its albums.
+- **An Import page in the GUI** (Settings → *Import from Google Photos*, or the import button in
+  the Photos header). Archives are staged by drag-and-drop onto the page or through the file
+  chooser, listed with their sizes so the set can be checked before anything is sent, and launched
+  as either a Scan (dry run) or a confirmed Import. The page shows live progress off the import's
+  job, keeps the finished run's report on screen, and can stop a run in flight; because the import
+  outlives the page, it is polled wherever the user navigates and its completion is reported as a
+  desktop notification.
+
+- SDK (`proton-sdk-rs` **0.6.1**): album **writes** — `ProtonPhotosClient::create_album` and
+  `add_photos_to_album`, ported from the TypeScript SDK (upstream C# has no album write API), plus
+  batch duplicate detection (`find_duplicates_many`, `name_collisions`). The workspace deps moved
+  `"0.6.0"` → `"0.6.1"` and `Cargo.lock` re-resolved to the registry crates. Adding a photo from an
+  album *shared with us* (a different volume) is still unported and fails that photo's outcome.
+- **Multi-select in Files.** Both views select a batch (click-drag, Ctrl-click, Shift-click); a bar
+  slides in reporting the count and offering Move to Trash and offline on/off for the whole
+  selection. Delete acts on everything selected, Esc clears it, and right-clicking inside a
+  selection offers the batch actions rather than the one row under the pointer. Actions that need a
+  single subject — rename, move, share, revisions — stay single-entry, and the details pane steps
+  aside for a batch instead of speaking for it.
+- **Undo on trash.** "Moved *X* to Trash" now carries an Undo that restores the batch, single files
+  included.
+- **The empty states are a place to act**: an empty folder offers Upload files / New folder, and an
+  empty photo timeline offers Upload photos / Import from Google Photos, instead of describing what
+  the user could go and do elsewhere.
+- **Ctrl+F works from any page**, navigating to Files and focusing the search box, rather than being
+  silently inert everywhere but Files.
+- Staged Takeout archives survive closing the window; archives that have since been moved or deleted
+  are dropped from the restored set.
+
+### Fixed
+- Settings showed the local cache as "X of 0 B used" when no cache budget was set. An unset budget
+  means *unlimited*, so it now reads "X cached — no limit set" rather than implying a zero cap.
+- The cache-budget editor fired a `SetCacheBudget` round-trip — and a toast — on every step, so a
+  run of `+` clicks applied a series of caps the user never asked for and stacked a column of
+  toasts. It now waits for the value to settle.
+- A long pin list pushed everything below it off the end of Settings. It shows the first six with a
+  "Show all N" row for the rest.
+
+## [1.8.2] — 2026-08-17
+
+Closes the two findings 1.8.1's live verification produced (B85, B86) and finishes the data-safety
+audit entries that had been sitting as "fixed in code, verification pending" since 1.0 (B49–B55).
+No schema change. Schema: **28**.
+
+The read path no longer assumes a revision is a series of 4 MiB blocks; it takes the geometry from
+the revision. The B85 investigation also **contradicted its own bug report** — see Notes, because
+the conclusion recorded there was that reads of such files were losing data, and they were not.
+
+### Fixed
+- A folder switched from mirror to on-demand now shows the files the mirror pass itself uploaded.
+  The sync engine created nodes on the remote without invalidating the parent's cached child
+  listing, and that listing is a database flag rather than an in-memory cache — so it survived a
+  daemon restart, and the files stayed invisible until the folder was switched back. Every remote
+  mutation the engine makes (folder create, file upload, and the three trash paths) now drops the
+  parent's cached listing by uid, which reaches a folder that no mount has resident — the case a
+  mirror folder always is (`docs/BUGS.md` B86).
+- `pdfs ls` and `pdfs refresh` accept a path under any mount the daemon owns, not only the primary
+  one. Both previously answered "is not under the mountpoint" for anything inside a secondary
+  on-demand mount, which left a folder serving a stale listing with no manual way to re-enumerate
+  it. A path under nothing this daemon has mounted still gets the same error as before.
+- A file whose blocks are not 4 MiB is no longer read twice over. Block offsets came from
+  `index * 4 MiB`, so on a revision laid out differently every block the client asked for
+  straddled two of the revision's own, and each was fetched and decrypted to answer for one — then
+  cached at boundaries the next read would not ask about. Offsets now come from the revision's
+  recorded block sizes, and the on-disk cache, the in-memory ring and the in-flight fetch key
+  address a block by the byte range it covers rather than by its index (`docs/BUGS.md` B85).
+
+### Changed
+- The block cache records each block's plaintext start alongside its `(mtime, size)` tag, and each
+  revision's block table in a small sidecar beside its blocks. Blocks cached by an earlier release
+  carry no start; they are honoured wherever the old 4 MiB assumption and the new plan agree on
+  the offset, which is every file this client uploaded — so the existing cache survives the
+  upgrade intact and is quietly refetched only for the files it was placing wrongly.
+
+### Notes
+- **B85's diagnosis was wrong, and the entry has been corrected rather than closed.** It read a
+  set of journal lines as proof that this client was requesting wrong byte ranges and being saved
+  only by B84's repair path. `RevisionReader::read_at` does not work that way: it plans over the
+  revision's real block sizes and clamps every block to the range asked for, identically in the
+  0.6.0 the client builds against and in every earlier version. A read can therefore never return
+  more bytes than it requested — yet every quoted line shows exactly that (`blen=4194304
+  got=4939506`), and the one place in the client that logs that shape can only reach it on the
+  opposite condition. The numbers were either transcribed with two fields swapped or captured from
+  a build not in the history; they want re-capturing from the journal before anything is concluded
+  from them. What was real is the assumption itself, and that is what this release removes — a
+  cost fix, not a correctness one. Nothing here changes what a read returns.
+- The first read of a file still plans on the 4 MiB assumption, and learns the real geometry as a
+  side effect of opening the reader it needs anyway. Resolving a reader merely to *plan* would
+  reintroduce the per-read key derivation the block cache exists to avoid, so the first read of a
+  non-4-MiB file pays one straddling fetch and then self-corrects.
+- Seven data-safety audit entries (B49–B55) moved from "fixed in code, verification pending" to
+  verified. The fixes were all genuinely present and needed no change; what they lacked was the
+  injected-failure testing each entry asked for, and that is what was written — unwritable
+  directories and `chmod 000` subtrees for permission failures, a real `/dev/shm`↔`/tmp` device
+  boundary for the cross-filesystem fallbacks, SQLite's `max_page_count` for a full disk, an abort
+  trigger for a failed insert, and truncated and unpublished sidecars for the crash boundaries.
+  Two seams were added to make failure arrangeable at all: `stage_write_at`, mirroring the
+  `preserve_write_at` that already existed, and `walk_local_tree` lifted out of the sync engine so
+  the local scan can be driven against a real tree without a daemon.
+- **Two of those entries are not fully closed, and say so.** B51 and B52 concern crash consistency,
+  and nothing short of a machine actually losing power tests that; the crash *boundaries* are
+  covered by reconstructing on disk exactly what a crash at each point leaves. B54 also diverges
+  from its required fix on purpose: it has no "deliberate delete" confirmation path, so a total
+  local wipe is refused outright rather than offered for confirmation. That is stricter than asked
+  for, and the cost is that a user who really did delete everything must remove and re-add the
+  sync folder.
+- B86's fix routes only `ls` and `refresh` to the owning mount. The other path-addressed control
+  requests — pin, rename, move, delete, sharing — still resolve against the primary mount only.
+  That is a larger change and was not what blocked the repro; it is recorded as an open follow-up
+  (`docs/BUGS.md` B88).
+- Three findings were opened rather than fixed: the geometry above is learned one read late, so a
+  non-4-MiB file pays a single wasted fetch on its first read (B87); the remaining path-addressed
+  control requests are still primary-only (B88); and the container-level `CLAUDE.md` still
+  describes the SDK dependency as 0.1.11 when 1.7.1 bumped it to 0.6.0, which is what sent the
+  B85 investigation to the wrong source tree to begin with (B89).
+
+## [1.8.1] — 2026-08-16
+
+Some files read short through the mount and reported success — an application got a truncated
+copy with nothing anywhere saying so (`docs/BUGS.md` B84). Found because GNOME's file indexer
+kept complaining that PNGs under `~/ProtonDrive/Pictures` were corrupt; it was right. The rest
+of this release is the long-standing architectural backlog from the July concurrency audits
+(B25, B32, B39, B40, B43, B44), each verified against the current code before being fixed.
+Schema: **28** — migration V28 adds `sync_entry.local_mtime_ns`.
+
+### Fixed
+- A read no longer trusts a revision whose recorded block sizes disagree with the file's size.
+  Such a file leaves the block/range path entirely: it is fetched through the whole-file,
+  manifest-verified download — the same path `pdfs pin` uses, and the reason pinning was the
+  workaround — and served from the resulting cached blob. One download per file however many
+  reads discover the problem at once, and files above 512 MiB fail `EIO` with a note to pin
+  them rather than pulling down gigabytes for one read.
+- A block that comes back shorter than the file's size implies is never served, cached or kept
+  in memory. Assembling a read out of short blocks is what quietly produced the truncation:
+  the missing bytes were simply not appended, the kernel handed userspace a short read, and
+  every tool reads a short read as end-of-file.
+- A synced folder no longer reports the same deletion as an error on every pass. Deleting a
+  local file that something else had already deleted counted as a failure, which kept its
+  baseline and made the next pass try again — forever. A path that is already gone is the
+  state the sync pass wanted (`docs/BUGS.md` B42).
+- A mirror folder no longer misses an edit made in the same second as its last sync. Change
+  detection compared whole seconds, so rewriting a file in place without changing its length
+  read as "unchanged" and never uploaded — the remote silently stayed behind until something
+  else about the file moved. Baselines now record the modification time to nanoseconds
+  (`docs/BUGS.md` B25).
+- A sync download no longer overwrites an edit that finished while it was running. The
+  destination is re-checked in the last moment before the download is published, and a local
+  file that has moved on since the pass planned for it is kept as a conflict copy — the same
+  resolution a both-sides-changed conflict gets (`docs/BUGS.md` B39).
+- An upload interrupted by a writer no longer reports itself as synchronized. The baseline now
+  records the content that actually went up rather than whatever is on disk when the transfer
+  ends, so a revision torn by a concurrent write is replaced by a clean one on the next pass
+  instead of standing as the file's content on Drive (`docs/BUGS.md` B40).
+- Listing a directory that changes while it is being read no longer skips or repeats entries.
+  `readdir` resumed by index into a listing rebuilt on every call, so a create or a trash
+  between two pages shifted everything after it. The listing is now frozen for the life of the
+  directory handle (`docs/BUGS.md` B43).
+- Opening a file for writing while a previous close is still publishing no longer discards that
+  close's revision. The base is re-checked at the moment the write handle is installed, rather
+  than trusted across a copy that can be the size of the whole file (`docs/BUGS.md` B32).
+- Unmounting now stops and joins the daemon's background workers instead of leaving them
+  running. The drain, sync engine, conflict sweep, online probe, local indexer and control
+  listener share a stop signal and interruptible waits, so an in-process remount no longer
+  starts a second set on top of the first (`docs/BUGS.md` B44).
+
+### Notes
+- The size `stat` reports was always the correct one; it is the reader's belief about where
+  blocks end that was wrong, so nothing about reported sizes changes.
+- Verified live on the affected account: four multi-block PNGs that had been reading short now
+  deliver their full size, and the journal shows each one repaired. The diagnostics also
+  answered the open question, and not as expected — the revision metadata is fine; those files
+  simply do not have 4 MiB blocks, and this client assumes they do. Filed as `docs/BUGS.md`
+  B85. Until that is fixed, a file with non-4-MiB blocks is downloaded whole on its first read.
+- Migration V28's new column is nullable rather than converted from the existing seconds. A
+  baseline row written before this release has no sub-second time to recover, and inventing
+  zero for it would make every already-synced file compare as changed and re-upload an entire
+  mirror on first start; `NULL` keeps those rows comparing exactly as they did, and each gains
+  a real value the next time its path syncs.
+- Three audit entries closed without a code change, having been fixed already or being correct
+  as they stand: sync-folder removal is serialized against reconciliation (B41), the drain's
+  database contention was removed by the read-only connection pool and the claim column (B30),
+  and the refusals for symlinks, hard links, device nodes and `chmod` are deliberate — Drive
+  cannot represent them, and a local-only representation no other Proton client can read would
+  be worse than a clean refusal (B31).
+- Six of this release's fixes were then driven live against the installed 1.8.1 on a real
+  account: the same-second edit uploads (B25), three rapid rewrites of a 64 MiB file publish the
+  third one byte for byte (B32), a write racing a download survives as a conflict copy (B39), an
+  upload torn by a concurrent write heals itself on the following pass (B40), a `getdents64`
+  walk with a 160-byte buffer against a directory mutated between pages returns every entry
+  exactly once (B43), and a restart of a daemon with six mounts and a busy drain stops in 110 ms
+  and comes back at the same thread count (B44). B42 could not be driven from a single machine —
+  see B86 below.
+- One new bug came out of the verification: an on-demand mount serves a folder listing that
+  predates the sync engine's own uploads, so files the mirror pass created are invisible until
+  the folder is switched back (`docs/BUGS.md` B86). Nothing is lost — they are on the server and
+  come back on the next mirror pass — but they cannot be seen or named while the folder is
+  on-demand, which is also what blocks B42's live verification.
+
+## [1.8.0] — 2026-08-16
+
+A queued write whose node had left the local tree was retried every five seconds forever and
+counted as an ordinary pending upload — 28 of them, holding 18.4 GiB, had been doing that for
+30 days on the machine that found it (`docs/BUGS.md` B83). Schema: 27 — migration V27 adds
+`pending_op.access_deferred_since`.
+
+### Fixed
+- The drain no longer reads "I have never heard of this node" as "you may not write this
+  node". A missing authority is now resolved against the remote: the node is re-interned if
+  it is still there, and reported as a real failure if it is gone. Ops that had been stuck
+  invisibly for weeks now say what is wrong with them on the first pass.
+- A create or mkdir resolves its *parent* as the authority, so the refetch asks about the
+  folder rather than the node it has not made yet.
+
+### Added
+- Access deferrals are bounded. A deferral still costs no attempt and records no error for
+  the first five minutes — the case it exists for is a share downgraded mid-queue and undone
+  a moment later — but past that window each recheck records a failure, so the op enters the
+  ordinary backoff and appears in `failing_ops` and the `pdfs status` error text like any
+  other stuck operation. The first deferral of a run is logged at `warn` rather than `debug`.
+
+### Notes
+- No staged data is touched by any of this. A reported failure keeps its `pending_op` row and
+  its staged blob exactly as before; the change is in what the user is told, and in the queue
+  no longer waiting on a permission change that was never coming.
+
+## [1.7.1] — 2026-08-16
+
+Write-back throughput follow-up to 1.7.0, same audit
+(`docs/plans/audit-2026-08-15-perf-locks.md`). Schema: 26 — migration V26 adds
+`pending_op.claimed_at`.
+
+### Added
+- Parallel write-back drain: three workers share the queue through a `pending_op.claimed_at`
+  claim column (migration V26), so a large upload no longer holds every queued rename, trash
+  and small write behind it. Ordering is preserved per node — the claim query never offers
+  two workers ops for the same uid — and claims left by a crashed run are cleared at open.
+- An upload already on the wire is cancelled when a newer write, a trash or a discard
+  supersedes it, instead of spending the uplink on a revision the next operation replaces.
+
+### Changed
+- The revision debounce is adaptive: it widens toward how long that node's last upload
+  actually took (bounded to 2–60 s), so a file saved faster than it can be sent supersedes
+  in the queue rather than mid-upload.
+- Workspace deps bumped to `proton-sdk` / `proton-drive-rs` 0.6.0.
+
+## [1.7.0] — 2026-08-16
+
+Performance and robustness pass over the mount, from the architecture audit in
+`docs/plans/audit-2026-08-15-perf-locks.md`. Schema: 25.
+
+### Added
+- Sequential-read prefetch (`Core::prefetch_ahead`): per-file sequential detection, depth
+  doubling 2→8, reset to 0 after a seek, skipping blocks already cached, and bounded by its
+  own permit budget so it can never queue ahead of a demand read.
+- Single-flight block fetching (`BlockFlight`) keyed on `(uid, mtime, size, block)`, so a
+  demand read, kernel read-ahead and prefetch of the same block share one download+decrypt.
+- In-memory block LRU (`BlockRing`) in front of *both* block paths; a block read off disk is
+  promoted into it, so the following ~31 kernel reads of that 4 MiB block cost nothing.
+- Read-only SQLite connection pool (`ReadPool` / `Db::read`) with every `SELECT`-only method
+  routed at it, so a read no longer waits on the write connection.
+- `nodes.path` persisted and backfilled, replacing the recursive `path_of` walk.
+- Single-writer `flock` on the database; a `SQLITE_CORRUPT`/`NOTADB` file is quarantined as
+  `cache.db.corrupt-<ts>` (WAL sidecars too) and rebuilt rather than failing the mount.
+- `VACUUM` and the deep `integrity_check` now ack immediately and run as background jobs;
+  `pdfs doctor` polls for the verdict.
+- Staging reconcile at mount: staged blobs no queued operation refers to are re-queued, or
+  named in the log when they cannot be addressed.
+- Queue/staging visibility — `Status` gained `parked_uploads`, `failing_ops`,
+  `failing_error`, `staged_bytes`, `staged_oldest_secs`; `pdfs status` prints them when
+  non-zero.
+- `statfs` implemented against the account quota; FUSE `init` negotiates `max_readahead`,
+  `max_background`, `PARALLEL_DIROPS` and `CACHE_SYMLINKS`; `blksize` raised to 1 MiB.
+
+### Changed
+- `State` no longer writes to SQLite under the inode lock — mutations queue into an outbox
+  applied after the lock is released, so interning a 5000-child listing no longer commits a
+  transaction with the whole mount frozen.
+- Re-listing an unchanged folder no longer touches its subtree; when a subtree really moved,
+  one recursive walk carries both the new path and the inherited trashed flag.
+- `release(2)` no longer gap-fills from the network: it stages an incomplete blob from local
+  caches only and the drain thread finishes it off the dispatch loop.
+- A partial write over an undrained one is merged instead of refused.
+- Size-upgrade waiters park on a queue instead of occupying a worker thread, capped at 8
+  folders in flight; past the cap `stat` answers provisionally.
+- Block-cache disk writes moved off the read's critical path; no more fsync per cached block.
+- Cache LRU touches buffered in memory and flushed in one transaction.
+- Search: sync-folder list and pin lookups hoisted out of the per-hit loop.
+- SQLite tuned (`cache_size`, `mmap_size`, `temp_store=MEMORY`, `wal_autocheckpoint`) and
+  three new indexes added.
+- Mount registry lock released before FUSE teardown/join; kernel notifications batched under
+  the state lock and flushed after it.
+
+### Fixed
+- **Data loss:** `ENOSPC` is now propagated from `write`/`fsync`/staging instead of being
+  swallowed, with emergency eviction wired up and scratch marked durable before any staging
+  error; a failed `record_pending_write` fails `release` rather than dropping the write.
+- **Data loss:** the conflict sweep no longer discards queued operations after the trash
+  round trip.
+- **Data loss:** `rescue_scratch` moves a blob with an unreadable sidecar to `recovery/`
+  unaccompanied instead of fabricating a sidecar for it.
+- Own-sealed revisions are persisted (7-day TTL), so a restart no longer reopens the
+  transient-download fork window fixed in 1.1.0.
+- Depth-capped `is_pinned` (cycle-safe), daemon write timeout, and every client-supplied
+  `limit` clamped.
+- `recover_fsynced_writes` no longer scans the recovery directory on every idle pass.
+
+## [1.6.0] — 2026-08-12
+
+Search-index correctness and ranking (`docs/plans/search-index.md`). Schema: 21 —
+migration V21 rebuilds `nodes_fts`.
+
+### Fixed
+- **B80** — 29% of the account was missing from the search index. `node_is_indexable_tx`
+  required a null-parent ancestor, which only the My Files root has, so every node under a
+  device folder was dropped from `nodes_fts` on its first upsert after the v16 backfill
+  (2,705 of 9,252 nodes on the account this was diagnosed against). The rule now matches the
+  backfill, migration V21 replays it, nodes under a trashed folder stay out, and the walk is
+  depth-capped.
+- **B81** — the prompt labelled every Drive hit "My files", including device folders; pin
+  rows also took `is_dir` from `Pin::recursive`.
+- **B82** — a `parent_uid` cycle hung the daemon on any short search: the recursive CTEs in
+  `path_of` and the pin walk use `UNION ALL`, which does not deduplicate. `path_of` is now
+  depth-capped at 256 and returns the truncated path.
+
+### Changed
+- Local search ranking: whole-query prefix matches get their own lane (newest first) ahead
+  of trigram rank, which on a home directory full of dependency trees was burying the
+  obvious answer — 73% of the 500 best-ranked candidates for "test" came from one Go module
+  cache. The single-character lane, which recovers a typo that destroys every trigram, stays
+  behind it.
+
+## [1.5.0] — 2026-08-11
+
+Schema: 20.
+
+### Added
+- **`pdfs-prompt --dmenu`** — the same search through an external dmenu-style launcher
+  (fuzzel, rofi, wofi, tofi, bemenu, dmenu) instead of the built-in GTK HUD, so the prompt
+  matches a tiling-WM desktop. A launcher filters a fixed list rather than re-querying per
+  keystroke, so searching is a two-step loop; `--query` skips the first step, fuzzel and rofi
+  get file-type icons. Configurable as `"prompt": { "mode": "dmenu", "menu": [...] }`, with
+  `--gtk` overriding for one invocation.
+- **Configurable open-with rules** (`pdfs-core/src/opener.rs`): an ordered list of name/class
+  patterns in `config.json` under `open_with`, each mapped to argv and optionally wrapped in
+  a terminal, first match wins, falling back to `xdg-open`. Lets "open a text file" mean
+  `nvim` in a terminal without breaking every graphical caller. Absent config reproduces the
+  old behaviour exactly.
+
+### Fixed
+- The prompt and dmenu openers hand applications the cached file while matching rules
+  against the *original* Drive filename, so e.g. `.md` files stop being routed by their
+  cache-path extension.
+
+## [1.4.0] — 2026-08-10
+
+Schema: 20.
+
+### Added
+- **File version history** (`pdfs-fuse/src/revisions.rs` + a GTK versions dialog): list a
+  file's revisions, restore one, delete one, or write an old one out to a local path. A
+  restore re-points the file server-side, so no content crosses the wire and nothing enters
+  the drain queue; the daemon drops its cached content and repopulates on the next read.
+- **Persistent SDK entity cache** (`pdfs-core/src/sdkcache.rs`): the SDK's decrypted node
+  metadata now survives a daemon restart instead of re-walking the tree. It lives in its own
+  `sdk_cache.db`, deliberately off the daemon's hot `cache.db` mutex, holds no key material,
+  needs no migrations, and is cleared on logout.
+- Per-node outcomes for batch operations (`pdfs-core/src/batch.rs`): `trash`/`restore`/
+  `delete`/`move` report one result per node, so a node the server rejects no longer fails
+  the whole batch.
+- Photo viewer page in the GUI and richer photo metadata in the details pane.
+
+### Changed
+- SDK telemetry routed into `tracing`, so its transfer/block-storage/request spans land in
+  the daemon log instead of a no-op sink.
+- A file that fits in one block uploads as a single atomic request rather than the
+  draft/block/commit sequence.
+
+## [1.3.0] — 2026-07-31
+
+Schema: 19.
+
+### Added
+- **Photo albums** — `PhotoAlbums` / `AlbumPhotos` control requests, daemon-side `albums.rs`
+  and a GUI albums page (the former gallery view, renamed). Albums other people share with
+  you are included; their photos are persisted per album because a shared album's photos
+  never appear in your own timeline. Served stale-while-refreshing like the timeline.
+- **GUI "Locations" page** — one row per mount spec: the primary `~/ProtonDrive` mount
+  alongside every folder this computer backs up, mirrored or on-demand. Called *Locations*
+  rather than *Mounts* because a mirror folder is a plain directory with no FUSE session.
+  It absorbs the old Computers page's actions and the mountpoint chooser from Settings.
+- `role` on shared-node metadata (`viewer`/`editor`/`admin`), defaulted for wire-compat with
+  older clients and daemons.
+- FUSE acceptance coverage for the permission-based mounts.
+
+## [1.2.1] — 2026-07-31
+
+Schema: 18.
+
+### Fixed
+- Migration bug that could leave the `ProtonDrive` mount unwritable after upgrade.
+- Permission error on on-demand mounts.
+- B78.
+
+### Changed
+- Release pipeline: `.deb` signing added and `.rpm` signing fixed.
+
+## [1.2.0] — 2026-07-29
+
+Sharing and multi-mount release. Schema: 18.
+
+### Added
+- **Shared with me**: shares others sent you are listed, verified and mountable, including on
+  the primary mount.
+  They appear under a synthetic `Shared with me` directory on a virtual volume
+  (`pdfs-fuse/src/virtual.rs`), with name collisions and over-long components resolved by
+  its own naming rules.
+- Per-share access model (`db/share_access.rs`): the effective role of each shared root is
+  persisted and kept resident in mount state, so interning an inode never costs a query. The
+  database stays the restart/offline authority — every role change is written through before
+  the cache updates. A share you cannot write is presented POSIX read-only.
+- Unified location model (`pdfs-core/src/mounts.rs`, `db/mounts.rs`): one presentation shape
+  for every local Proton Drive location, joining device sync state with a new `mount` table.
+  `MountMode` is `Mirror` (full local copy, reconciled both ways) or `OnDemand` (FUSE session
+  fetching on access), with an `Unknown` fallback so a mode written by a newer client does
+  not break an older one.
+
+## [1.1.1] — 2026-07-27
+
+Schema: 16.
+
+### Fixed
+- Trash refresh did not pull updates.
+- Packaging: `PKGBUILD` was left at 1.1.0 by the 1.1.1 version bump, failing the release
+  workflow's tag/manifest/PKGBUILD agreement check.
+
+## [1.1.0] — 2026-07-26
+
+Conflict-handling and concurrency release. Schema: 16.
+
+### Added
+- Conflict sweep (`pdfs-fuse/src/sweep.rs`, 5-minute cadence): removes conflict copies proven
+  identical by size + `content_sha1`, surfaces divergent ones once as an activity entry, and
+  never removes what it cannot prove.
+- Sweep mode and `.pdfsignore`-driven conflict handling; ignore rules are rebuilt per sync
+  pass so edits take effect without a restart.
+- Substantially extended FUSE acceptance suite.
+
+### Fixed
+- **B69** — spurious `(sync-conflict)` copies. Revision identity now uses the server's
+  `revision_id` rather than `(mtime, size)`, which the server re-stamps on seal; the planner
+  gained `AdoptBaseline` so an equal-size no-baseline pair is recorded instead of forked on
+  first reconcile.
+- **B70** — browser downloads into an on-demand mount had their in-flight temporaries sealed
+  as canonical revisions. Transient names are recognised and held until the name is finalized.
+- Assorted race conditions and concurrency bugs on the write/drain paths.
+
+### Changed
+- Workspace deps bumped to `proton-sdk` / `proton-drive-rs` 0.2.2.
+
+## [1.0.0] — 2026-07-22
+
+First stable release: FUSE files-on-demand mount, sync daemon under `proton-drive.service`,
+`pdfs` CLI and the GTK4 app, on top of the pure-Rust Proton Drive SDK. Schema: 16.
+
+### Fixed
+- The outstanding FUSE defects tracked in `docs/BUGS.md`, plus a truncate defect, validated
+  by a new POSIX compliance suite for the filesystem.
+
+[1.8.2]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.8.2
+[1.8.1]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.8.1
+[1.8.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.8.0
+[1.7.1]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.7.1
+[1.7.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.7.0
+[1.6.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.6.0
+[1.5.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.5.0
+[1.4.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.4.0
+[1.3.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.3.0
+[1.2.1]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.2.1
+[1.2.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.2.0
+[1.1.1]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.1.1
+[1.1.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.1.0
+[1.0.0]: https://github.com/narrrl/proton-drive-linux/releases/tag/v1.0.0

docs/DEVELOPMENT.md

@@ -14,7 +14,8 @@ Consolidated from the historical feature roadmap; current bug status lives in [`
 * **Custom FUSE Mount Options (Horizon 1)**: Expose custom mounting parameters in configuration (e.g. `ro` for read-only, `direct_io` to bypass kernel caching, `allow_other`). Auto-generate systemd user mount units upon sync folder configuration.
 * **Symbolic Link & Hard Link Virtualization (Horizon 2)**: Add symbolic link virtualization inside the metadata store (`NodeType::Symlink`) by intercepting `readlink(2)` and `symlink(2)`. Targets should sync remotely as small encrypted metadata placeholder files on Drive (`proton-vfs-symlink: <target>`).
 * **Desktop File Manager Integration (Horizon 2)**: Develop shell extension plugins for popular Linux file managers (Nautilus Python plugin, Dolphin Service Menus, Thunar custom actions) to offer context-menu shortcuts ("Pin", "Unpin", "Copy Share Link", "View Version History") and file overlay sync badges.
-* **Integrated Photo Gallery Enhancements (Horizon 2)**: Support creating and editing Proton Photo Albums (album *writes* are unported in the SDK too) and create an auto-upload Pictures folder pipeline. Exif display, the date-based timeline scrubber and favourites are implemented.
+* **Integrated Photo Gallery Enhancements (Horizon 2)**: Album *editing* — rename, cover photo, delete, and removing photos from an album — is still unported in the SDK (TS `updateAlbum` / `deleteAlbum` / `removePhotos`), as is adding a photo that lives on someone else's volume (TS `copyPhoto`). Album **creation** and adding own-volume photos landed with the Google Photos import. Still open: an auto-upload Pictures folder pipeline, and a GUI for creating albums by hand. Exif display, the date-based timeline scrubber and favourites are implemented.
+* **Google Photos import follow-ups**: the importer uploads photos one at a time — a large export would finish sooner with a bounded concurrent upload pool. Trash folders are recognized by a hardcoded list of localized names ([`takeout.rs`](../crates/pdfs-core/src/takeout.rs) `TRASH_FOLDERS`); a locale not on it imports its trash as ordinary photos. Motion-photo `.MP`/`.MV` sidecar videos are ignored rather than uploaded as related photos. Live validation against a real export is pending.
 * **Random-Access Media Streaming seek support (Horizon 2)**: Intercept out-of-order sparse reads (player seeks) in `pdfs-fuse` and prioritize downloading blocks around the seek offset, aborting/postponing sequential pre-fetches.
 * **Dynamic Sync Dashboard & Queue Visualization (Horizon 2)**: GUI real-time transfer list (progress bars, speed, ETA), sync history feed, storage usage breakdown, and global pause/resume sync controls.
 * **Interactive Terminal UI (TUI) Mode (Horizon 3)**: Implement `pdfs tui` using the `ratatui` crate to show transfer speed, sync status, active transfer queue with progress bars, and scrolling daemon logs.

packaging/PKGBUILD

@@ -9,7 +9,7 @@
 # Build + install:   cd packaging && makepkg -fi
 
 pkgname=proton-drive-linux
-pkgver=1.5.0
+pkgver=1.9.0
 pkgrel=1
 pkgdesc="Proton Drive client for Linux: FUSE files-on-demand mount, CLI, GTK4 app + tray"
 arch=('x86_64')