feat(fuse,core): number inodes by local id

A node's inode is now derived from its row's local id instead of a
per-run counter, so the same node keeps the same inode across restarts
and across every place that interns it. A lid handed out before the
row is stored reads as no node.

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

@@ -17,6 +17,8 @@ use super::utils::{
 pub struct StoredNode {
     pub node: Node,
     pub listed: bool,
+    /// The row's local id ([`Db::lid_of`]).
+    pub lid: i64,
 }
 
 /// One full-text search match: the stored [`Node`] plus its mountpoint-relative
@@ -289,7 +291,8 @@ impl Db {
         let uid_str = parent_uid.to_string();
         let conn = self.read();
         let count: i64 = conn.query_row(
-            "SELECT COUNT(*) FROM nodes WHERE parent_uid = ?1 AND trashed = 0",
+            "SELECT COUNT(*) FROM nodes
+             WHERE parent_uid = ?1 AND trashed = 0 AND node_json IS NOT NULL",
             params![uid_str],
             |row| row.get(0),
         )?;
@@ -305,9 +308,11 @@ impl Db {
     pub fn node_path(&self, uid: &str) -> Result<Option<String>> {
         let conn = self.read();
         let exists: Option<i64> = conn
-            .query_row("SELECT 1 FROM nodes WHERE uid = ?1", params![uid], |r| {
-                r.get(0)
-            })
+            .query_row(
+                "SELECT 1 FROM nodes WHERE uid = ?1 AND node_json IS NOT NULL",
+                params![uid],
+                |r| r.get(0),
+            )
             .optional()?;
         if exists.is_none() {
             return Ok(None);
@@ -511,17 +516,17 @@ impl Db {
     pub fn load_all(&self) -> Result<Vec<StoredNode>> {
         let conn = self.read();
         let mut stmt =
-            conn.prepare("SELECT node_json, listed FROM nodes WHERE node_json IS NOT NULL")?;
+            conn.prepare("SELECT node_json, listed, lid FROM nodes WHERE node_json IS NOT NULL")?;
         let rows = stmt.query_map([], |row| {
             let json: String = row.get(0)?;
             let listed: i64 = row.get(1)?;
-            Ok((json, listed != 0))
+            Ok((json, listed != 0, row.get(2)?))
         })?;
         let mut out = Vec::new();
         for row in rows {
-            let (json, listed) = row?;
+            let (json, listed, lid) = row?;
             let node: Node = serde_json::from_str(&json)?;
-            out.push(StoredNode { node, listed });
+            out.push(StoredNode { node, listed, lid });
         }
         Ok(out)
     }
@@ -556,6 +561,45 @@ impl Db {
             .optional()?)
     }
 
+    /// The local id of each node, in order, giving a row to each that has none.
+    ///
+    /// A new row is only a stub: it has no `node_json`, so no listing or search
+    /// returns it until the node is upserted, which the caller still owes. That
+    /// keeps this cheap enough to call with the inode lock held, which is
+    /// where an inode number is first needed.
+    pub fn lids_for(&self, nodes: &[&Node]) -> Result<Vec<i64>> {
+        let mut conn = self.conn.lock();
+        let tx = conn.transaction()?;
+        let mut lids = Vec::with_capacity(nodes.len());
+        {
+            let mut known = tx.prepare_cached("SELECT lid FROM nodes WHERE uid = ?1")?;
+            let mut stub = tx.prepare_cached(
+                "INSERT INTO nodes (uid, parent_uid, name, is_dir, mtime, trashed)
+                 VALUES (?1, ?2, ?3, ?4, ?5, ?6)",
+            )?;
+            for node in nodes {
+                let uid = node.uid.to_string();
+                let lid = match known.query_row(params![uid], |r| r.get(0)).optional()? {
+                    Some(lid) => lid,
+                    None => {
+                        stub.execute(params![
+                            uid,
+                            node.parent_uid.as_ref().map(ToString::to_string),
+                            node.name,
+                            node.is_folder() as i64,
+                            node.modification_time,
+                            node.trashed as i64,
+                        ])?;
+                        tx.last_insert_rowid()
+                    }
+                };
+                lids.push(lid);
+            }
+        }
+        tx.commit()?;
+        Ok(lids)
+    }
+
     /// Read the persisted incremental-sync cursor (a `DriveEventId`), if any.
     /// The daemon resumes from this on restart instead of reseeding to the
     /// server head, so changes made while unmounted are still applied (P2).
@@ -816,8 +860,10 @@ fn reindex_subtree_tx(
     let mut set_path = tx.prepare("UPDATE nodes SET path = ?2 WHERE rowid = ?1")?;
     let mut unindex = tx.prepare("DELETE FROM nodes_fts WHERE rowid = ?1")?;
     let mut index = tx.prepare(
+        // Not a stub row (`Db::lids_for`): it is indexed when its node is
+        // written.
         "INSERT INTO nodes_fts (rowid, name, path)
-         SELECT rowid, name, ?2 FROM nodes WHERE rowid = ?1",
+         SELECT rowid, name, ?2 FROM nodes WHERE rowid = ?1 AND node_json IS NOT NULL",
     )?;
     for (rowid, path, blocked) in descendants {
         set_path.execute(params![rowid, path])?;

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

@@ -98,7 +98,7 @@ impl Db {
     pub fn effective_node_access(&self, uid: &NodeUid) -> Result<Option<Access>> {
         let conn = self.read();
         let exists: bool = conn.query_row(
-            "SELECT EXISTS(SELECT 1 FROM nodes WHERE uid = ?1)",
+            "SELECT EXISTS(SELECT 1 FROM nodes WHERE uid = ?1 AND node_json IS NOT NULL)",
             [uid.to_string()],
             |row| row.get(0),
         )?;

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

@@ -3145,6 +3145,31 @@ fn a_node_keeps_its_lid_across_updates_and_a_new_one_never_reuses_it() {
     assert!(c > b, "lid {c} reuses one a deleted row had");
 }
 
+#[test]
+fn a_lid_handed_out_before_the_node_is_stored_reads_as_no_node() {
+    let db = Db::open_in_memory().unwrap();
+    db.upsert_node(&folder("root", None, "My Files")).unwrap();
+    db.set_share_access(&uid("root"), crate::Access::Owner)
+        .unwrap();
+    let stub = file("stub", "root", "stub.txt", 1);
+    let [lid] = db.lids_for(&[&stub]).unwrap()[..] else {
+        panic!("one lid per node");
+    };
+
+    assert_eq!(db.lid_of(&uid("stub").to_string()).unwrap(), Some(lid));
+    assert_eq!(db.lids_for(&[&stub]).unwrap(), vec![lid]);
+    assert!(db.node_by_uid(&uid("stub").to_string()).unwrap().is_none());
+    assert!(db.effective_node_access(&uid("stub")).unwrap().is_none());
+    assert!(db.node_path(&uid("stub").to_string()).unwrap().is_none());
+    assert!(!db.has_children(&uid("root")).unwrap());
+    assert!(db.search("stub", 10).unwrap().is_empty());
+    assert!(db.load_all().unwrap().iter().all(|n| n.lid != lid));
+
+    db.upsert_node(&stub).unwrap();
+    assert_eq!(db.lid_of(&uid("stub").to_string()).unwrap(), Some(lid));
+    assert!(db.has_children(&uid("root")).unwrap());
+}
+
 #[test]
 fn a_landed_placeholder_keeps_its_lid() {
     let db = Db::open_in_memory().unwrap();

crates/pdfs-fuse/src/devices.rs

@@ -625,7 +625,7 @@ impl Core {
         let mut fork = self.clone();
         fork.primary = false;
         let share_access = self.state().share_access.clone();
-        fork.state = Arc::new(Mutex::new(State::new(self.db.clone(), share_access, 2)));
+        fork.state = Arc::new(Mutex::new(State::new(self.db.clone(), share_access)));
         // 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`.

crates/pdfs-fuse/src/lib.rs

@@ -1754,21 +1754,23 @@ impl Core {
         let hidden = self.hidden.lock().clone();
         let mut st = self.state();
 
-        // Pass 1: assign a stable inode to every uid (root is already mapped).
+        // Pass 1: give every uid its inode from its local id (the root is
+        // already mapped).
         for sn in &stored {
             if hidden.contains(&sn.node.uid) || st.by_uid.contains_key(&sn.node.uid) {
                 continue;
             }
-            let ino = st.next_ino;
-            st.next_ino += 1;
-            st.by_uid.insert(sn.node.uid.clone(), ino);
+            st.by_uid
+                .insert(sn.node.uid.clone(), state::lid_ino(sn.lid));
         }
 
         // Pass 2: materialize entries, resolving each parent's inode by uid.
         // Track folders flagged complete so their listings rebuild in pass 3.
         let mut listed_dirs: Vec<u64> = Vec::new();
         for sn in stored {
-            let StoredNode { mut node, listed } = sn;
+            let StoredNode {
+                mut node, listed, ..
+            } = sn;
             if hidden.contains(&node.uid) {
                 continue;
             }
@@ -8868,16 +8870,27 @@ mod tests {
         std::fs::create_dir_all(&dir_path).unwrap();
         let db = pdfs_core::db::Db::open(&dir_path.join("cache.db")).unwrap();
         let share_access = db.all_share_access().unwrap();
-        let st = crate::state::State::new(std::sync::Arc::new(db), share_access, 1);
+        let st = crate::state::State::new(std::sync::Arc::new(db), share_access);
         (st, TestDir(dir_path))
     }
 
     fn rooted_state(volume: &str, root_link: &str) -> (crate::state::State, TestDir) {
         let (mut state, dir) = state_test_helper();
         let root = node_helper_in_volume(volume, root_link, None, "root", true);
-        let root_ino = state.intern(0, root);
-        assert_eq!(root_ino, super::ROOT_INO);
-        state.entries.get_mut(&root_ino).unwrap().parent = root_ino;
+        // At the root inode, as `ProtonFs::new` puts it.
+        state.by_uid.insert(root.uid.clone(), super::ROOT_INO);
+        state.entries.insert(
+            super::ROOT_INO,
+            crate::state::Entry {
+                uid: root.uid.clone(),
+                parent: super::ROOT_INO,
+                node: root,
+                access: Access::Owner,
+                lookup_count: 1,
+                open_count: 0,
+                unlinked: false,
+            },
+        );
         (state, dir)
     }
 

crates/pdfs-fuse/src/mount.rs

@@ -409,7 +409,7 @@ pub(crate) fn mount_with(
         maintenance: Arc::new(Mutex::new(Default::default())),
         primary_root_uid: root.uid.clone(),
         primary: true,
-        state: Arc::new(Mutex::new(State::new(db.clone(), share_access, 2))),
+        state: Arc::new(Mutex::new(State::new(db.clone(), share_access))),
         cache: Arc::new(cache),
         readers: Arc::new(Mutex::new(HashMap::new())),
         block_ring: Arc::new(Mutex::new(BlockRing::default())),

crates/pdfs-fuse/src/state.rs

@@ -201,6 +201,18 @@ pub(crate) struct PendingRevision {
 /// time so this module stays free of `fuser`.
 pub(crate) type DirListing = Vec<(u64, bool, String)>;
 
+/// Where [`State::next_ino`] starts: far above any local id a database hands
+/// out, so a fallback inode never names a node that has a row.
+pub(crate) const FALLBACK_INO: u64 = 1 << 48;
+
+/// The inode of the node with local id `lid` ([`Db::lids_for`]), except where
+/// it is a mount's root, which is always [`crate::ROOT_INO`]. One above the lid,
+/// so no other node takes the root's number. The same in every mount and after
+/// a restart.
+pub(crate) fn lid_ino(lid: i64) -> u64 {
+    lid.unsigned_abs() + crate::ROOT_INO
+}
+
 /// Mutable inode bookkeeping, guarded by a mutex because fuser drives the
 /// `Filesystem` trait through `&self`.
 pub(crate) struct State {
@@ -211,6 +223,8 @@ pub(crate) struct State {
     /// Cached directory listings: parent inode -> child inodes. Presence of a
     /// key means the directory has been enumerated.
     pub(crate) children: HashMap<u64, Vec<u64>>,
+    /// The next inode for a node the database could not give a local id, from
+    /// a range lids never reach ([`FALLBACK_INO`]).
     pub(crate) next_ino: u64,
     /// Shared write state keyed by inode. Concurrent writers share the scratch file.
     pub(crate) active_writes: HashMap<u64, WriteHandle>,
@@ -349,9 +363,6 @@ impl Drop for StateGuard<'_> {
 impl State {
     /// A fresh, empty inode space over `db`.
     ///
-    /// `next_ino` differs by caller: a real mount hands out [`crate::ROOT_INO`]
-    /// to its root and starts allocating above it, while a bare state under test
-    /// has no root and starts at 1.
     /// Apply the write-throughs this state owes SQLite, here and now.
     ///
     /// Production code never calls this: [`StateGuard`] releases the inode lock
@@ -378,12 +389,15 @@ impl State {
         self.db.clone()
     }
 
-    pub(crate) fn new(db: Arc<Db>, share_access: HashMap<NodeUid, Access>, next_ino: u64) -> Self {
+    /// A fresh, empty inode space over `db`. A node's inode comes from its
+    /// local id ([`lid_ino`]); a real mount puts its root at
+    /// [`crate::ROOT_INO`].
+    pub(crate) fn new(db: Arc<Db>, share_access: HashMap<NodeUid, Access>) -> Self {
         Self {
             entries: HashMap::new(),
             by_uid: HashMap::new(),
             children: HashMap::new(),
-            next_ino,
+            next_ino: FALLBACK_INO,
             active_writes: HashMap::new(),
             handles: HashMap::new(),
             next_fh: 1,
@@ -881,7 +895,19 @@ impl State {
         self.intern_mem_with_access(parent, node, access)
     }
 
-    fn intern_mem_with_access(&mut self, parent: u64, mut node: Node, access: Access) -> u64 {
+    fn intern_mem_with_access(&mut self, parent: u64, node: Node, access: Access) -> u64 {
+        self.intern_mem_at(parent, node, access, None)
+    }
+
+    /// [`State::intern_mem_with_access`], with the inode a new entry takes when
+    /// the caller already has it ([`State::new_inos`]).
+    fn intern_mem_at(
+        &mut self,
+        parent: u64,
+        mut node: Node,
+        access: Access,
+        ino: Option<u64>,
+    ) -> u64 {
         if let Some(&ino) = self.by_uid.get(&node.uid) {
             let changed = self
                 .entries
@@ -900,8 +926,13 @@ impl State {
             }
             return ino;
         }
-        let ino = self.next_ino;
-        self.next_ino += 1;
+        let ino = match ino {
+            Some(ino) => ino,
+            None => self
+                .new_inos(&[&node])
+                .remove(&node.uid)
+                .unwrap_or_default(),
+        };
         self.by_uid.insert(node.uid.clone(), ino);
         self.entries.insert(
             ino,
@@ -918,6 +949,41 @@ impl State {
         ino
     }
 
+    /// The inodes for nodes that have no entry yet, from their local ids, in
+    /// one transaction. Should the database fail, they come from
+    /// [`State::next_ino`] instead, so the mount keeps working, with inodes
+    /// that last only this run. So do the inodes of virtual folders, which are
+    /// never stored.
+    fn new_inos(&mut self, nodes: &[&Node]) -> HashMap<NodeUid, u64> {
+        let (virtual_nodes, stored): (Vec<&Node>, Vec<&Node>) = nodes
+            .iter()
+            .partition(|node| crate::r#virtual::is_virtual_uid(&node.uid));
+        let mut inos = match self.db.lids_for(&stored) {
+            Ok(lids) => stored
+                .iter()
+                .zip(lids)
+                .map(|(node, lid)| (node.uid.clone(), lid_ino(lid)))
+                .collect(),
+            Err(error) => {
+                warn!(%error, "no local ids for new inodes; numbering them for this run");
+                self.run_inos(&stored)
+            }
+        };
+        inos.extend(self.run_inos(&virtual_nodes));
+        inos
+    }
+
+    fn run_inos(&mut self, nodes: &[&Node]) -> HashMap<NodeUid, u64> {
+        nodes
+            .iter()
+            .map(|node| {
+                let ino = self.next_ino;
+                self.next_ino += 1;
+                (node.uid.clone(), ino)
+            })
+            .collect()
+    }
+
     /// Decrement lookup count for an inode and prune if lookup_count == 0 && open_count == 0 && unlinked.
     pub(crate) fn forget_lookup(&mut self, ino: u64, nlookup: u64) -> Option<(u64, String)> {
         if let Some(entry) = self.entries.get_mut(&ino) {
@@ -963,9 +1029,22 @@ impl State {
             self.keep_revision_mtime(node);
         }
         self.outbox.push(DbWrite::Upsert(nodes.clone()));
+        let fresh: Vec<&Node> = nodes
+            .iter()
+            .filter(|node| !self.by_uid.contains_key(&node.uid))
+            .collect();
+        let mut inos = if fresh.is_empty() {
+            HashMap::new()
+        } else {
+            self.new_inos(&fresh)
+        };
         nodes
             .into_iter()
-            .map(|node| self.intern_mem(parent, node))
+            .map(|node| {
+                let access = self.access_for_node(parent, &node);
+                let ino = inos.remove(&node.uid);
+                self.intern_mem_at(parent, node, access, ino)
+            })
             .collect()
     }
 
@@ -1283,7 +1362,7 @@ mod tests {
         let dir = TempDir::new();
         let db = Db::open(&dir.0.join("cache.db")).unwrap();
         let share_access = db.all_share_access().unwrap();
-        let st = State::new(Arc::new(db), share_access, 1);
+        let st = State::new(Arc::new(db), share_access);
         (st, dir)
     }
 
@@ -1301,6 +1380,36 @@ mod tests {
         (st, dir, src, dst)
     }
 
+    /// A node's inode comes from its row's local id, so it is the same in
+    /// every mount, after the hot cache drops it, and after a restart.
+    #[test]
+    fn a_node_keeps_its_inode_across_mounts_evictions_and_restarts() {
+        let (mut st, _dir) = state();
+        let inos = st.intern_batch(
+            0,
+            vec![
+                node("a", "root", "a.txt", false),
+                node("b", "root", "b.txt", false),
+            ],
+        );
+        st.flush_outbox();
+        let db = st.db.clone();
+        assert_ne!(inos[0], inos[1]);
+        assert!(!inos.contains(&crate::ROOT_INO));
+
+        let mut other = State::new(db.clone(), HashMap::new());
+        assert_eq!(other.intern(0, node("b", "root", "b.txt", false)), inos[1]);
+
+        st.forget_mem(&uid("a"));
+        assert_eq!(st.intern(0, node("a", "root", "a.txt", false)), inos[0]);
+
+        let mut restarted = State::new(db, HashMap::new());
+        assert_eq!(
+            restarted.intern_batch(0, vec![node("a", "root", "a.txt", false)]),
+            [inos[0]]
+        );
+    }
+
     /// Audit A5. Moving a file out of a folder leaves that folder's DB row
     /// claiming a complete listing, so once the hot cache drops it, remote
     /// changes under it stop being seen. `relocate` has to clear both sides.