claw-store/src/claw_fuse.rs

@@ -42,6 +42,7 @@ mod sync;
 mod zfs;
 
 use cluster::blob::{BlobId, BlobStore};
+use cluster::snapshot::SnapshotStore;
 
 const TTL: Duration = Duration::from_secs(1);
 // Inode number layout:
@@ -52,34 +53,78 @@ const TTL: Duration = Duration::from_secs(1);
 //                    the whole store at mount time.
 const ROOT_INO: u64 = 1;
 const BLOBS_DIR_INO: u64 = 2;
+const SNAPSHOTS_DIR_INO: u64 = 3;
+// Snapshot dir inodes: 10_000..99_999 (up to 90k snapshots).
+const FIRST_SNAPSHOT_INO: u64 = 10_000;
+// Blob file inodes: 100_000..
 const FIRST_BLOB_INO: u64 = 100_000;
 
-/// Read-only FUSE mount over a BlobStore.
+/// Read-only FUSE mount over a BlobStore + SnapshotStore.
 struct ClawFuse {
     store: BlobStore,
-    /// Runtime for async BlobStore calls. fuser is sync so we
+    snapshots: SnapshotStore,
+    /// Runtime for async store calls. fuser is sync so we
     /// block_on inside each callback.
     runtime: tokio::runtime::Runtime,
     /// blob-hex → allocated inode. Populated on lookup.
     hex_to_ino: HashMap<String, u64>,
     /// inode → blob-hex. Reverse lookup for getattr / read.
     ino_to_hex: HashMap<u64, String>,
-    next_ino: u64,
+    /// snapshot name → allocated inode.
+    snapshot_to_ino: HashMap<String, u64>,
+    /// inode → snapshot name.
+    ino_to_snapshot: HashMap<u64, String>,
+    next_blob_ino: u64,
+    next_snapshot_ino: u64,
 }
 
 impl ClawFuse {
-    fn new(store: BlobStore) -> Result<Self> {
+    fn new(store: BlobStore, snapshots: SnapshotStore) -> Result<Self> {
         Ok(Self {
             store,
+            snapshots,
             runtime: tokio::runtime::Builder::new_current_thread()
                 .enable_all()
                 .build()?,
             hex_to_ino: HashMap::new(),
             ino_to_hex: HashMap::new(),
-            next_ino: FIRST_BLOB_INO,
+            snapshot_to_ino: HashMap::new(),
+            ino_to_snapshot: HashMap::new(),
+            next_blob_ino: FIRST_BLOB_INO,
+            next_snapshot_ino: FIRST_SNAPSHOT_INO,
         })
     }
 
+    fn alloc_blob_ino(&mut self, hex: &str) -> u64 {
+        let ino = *self
+            .hex_to_ino
+            .entry(hex.to_string())
+            .or_insert_with(|| {
+                let n = self.next_blob_ino;
+                self.next_blob_ino += 1;
+                n
+            });
+        self.ino_to_hex
+            .entry(ino)
+            .or_insert_with(|| hex.to_string());
+        ino
+    }
+
+    fn alloc_snapshot_ino(&mut self, name: &str) -> u64 {
+        let ino = *self
+            .snapshot_to_ino
+            .entry(name.to_string())
+            .or_insert_with(|| {
+                let n = self.next_snapshot_ino;
+                self.next_snapshot_ino += 1;
+                n
+            });
+        self.ino_to_snapshot
+            .entry(ino)
+            .or_insert_with(|| name.to_string());
+        ino
+    }
+
     fn dir_attr(ino: u64) -> FileAttr {
         FileAttr {
             ino,
@@ -133,12 +178,7 @@ impl ClawFuse {
             .block_on(self.store.load_manifest(&blob_id))
             .ok()
             .flatten()?;
-        let ino = *self.hex_to_ino.entry(hex.to_string()).or_insert_with(|| {
-            let n = self.next_ino;
-            self.next_ino += 1;
-            n
-        });
-        self.ino_to_hex.entry(ino).or_insert_with(|| hex.to_string());
+        let ino = self.alloc_blob_ino(hex);
         Some((ino, manifest.total_size))
     }
 }
@@ -156,17 +196,80 @@ impl Filesystem for ClawFuse {
             ROOT_INO if name == "blobs" => {
                 reply.entry(&TTL, &Self::dir_attr(BLOBS_DIR_INO), 0);
             }
+            ROOT_INO if name == "snapshots" => {
+                reply.entry(&TTL, &Self::dir_attr(SNAPSHOTS_DIR_INO), 0);
+            }
             BLOBS_DIR_INO => match self.resolve_hex(name) {
                 Some((ino, size)) => reply.entry(&TTL, &Self::file_attr(ino, size), 0),
                 None => reply.error(libc::ENOENT),
             },
+            SNAPSHOTS_DIR_INO => {
+                // /snapshots/<name>/ — must be an existing snapshot.
+                let exists = self
+                    .runtime
+                    .block_on(self.snapshots.get(name))
+                    .ok()
+                    .flatten()
+                    .is_some();
+                if exists {
+                    let ino = self.alloc_snapshot_ino(name);
+                    reply.entry(&TTL, &Self::dir_attr(ino), 0);
+                } else {
+                    reply.error(libc::ENOENT);
+                }
+            }
+            parent_ino if (FIRST_SNAPSHOT_INO..FIRST_BLOB_INO).contains(&parent_ino) => {
+                // /snapshots/<name>/<blob-hex> — file iff hex is in
+                // the snapshot's blob_ids AND the blob exists.
+                let snap_name = match self.ino_to_snapshot.get(&parent_ino).cloned() {
+                    Some(n) => n,
+                    None => {
+                        reply.error(libc::ENOENT);
+                        return;
+                    }
+                };
+                let manifest = match self
+                    .runtime
+                    .block_on(self.snapshots.get(&snap_name))
+                    .ok()
+                    .flatten()
+                {
+                    Some(m) => m,
+                    None => {
+                        reply.error(libc::ENOENT);
+                        return;
+                    }
+                };
+                let target = match BlobId::from_hex(name) {
+                    Ok(id) => id,
+                    Err(_) => {
+                        reply.error(libc::ENOENT);
+                        return;
+                    }
+                };
+                if !manifest.blob_ids.iter().any(|b| b == &target) {
+                    reply.error(libc::ENOENT);
+                    return;
+                }
+                match self.resolve_hex(name) {
+                    Some((ino, size)) => {
+                        reply.entry(&TTL, &Self::file_attr(ino, size), 0)
+                    }
+                    None => reply.error(libc::ENOENT),
+                }
+            }
             _ => reply.error(libc::ENOENT),
         }
     }
 
     fn getattr(&mut self, _req: &Request, ino: u64, _fh: Option<u64>, reply: ReplyAttr) {
         match ino {
-            ROOT_INO | BLOBS_DIR_INO => reply.attr(&TTL, &Self::dir_attr(ino)),
+            ROOT_INO | BLOBS_DIR_INO | SNAPSHOTS_DIR_INO => {
+                reply.attr(&TTL, &Self::dir_attr(ino))
+            }
+            n if (FIRST_SNAPSHOT_INO..FIRST_BLOB_INO).contains(&n) => {
+                reply.attr(&TTL, &Self::dir_attr(ino));
+            }
             _ => {
                 let hex = match self.ino_to_hex.get(&ino).cloned() {
                     Some(h) => h,
@@ -208,6 +311,7 @@ impl Filesystem for ClawFuse {
                 entries.push((ROOT_INO, FileType::Directory, ".".into()));
                 entries.push((ROOT_INO, FileType::Directory, "..".into()));
                 entries.push((BLOBS_DIR_INO, FileType::Directory, "blobs".into()));
+                entries.push((SNAPSHOTS_DIR_INO, FileType::Directory, "snapshots".into()));
             }
             BLOBS_DIR_INO => {
                 entries.push((BLOBS_DIR_INO, FileType::Directory, ".".into()));
@@ -221,17 +325,50 @@ impl Filesystem for ClawFuse {
                 };
                 for id in ids {
                     let hex = id.to_hex();
-                    let ino = *self
-                        .hex_to_ino
-                        .entry(hex.clone())
-                        .or_insert_with(|| {
-                            let n = self.next_ino;
-                            self.next_ino += 1;
-                            n
-                        });
-                    self.ino_to_hex
-                        .entry(ino)
-                        .or_insert_with(|| hex.clone());
+                    let ino = self.alloc_blob_ino(&hex);
+                    entries.push((ino, FileType::RegularFile, hex));
+                }
+            }
+            SNAPSHOTS_DIR_INO => {
+                entries.push((SNAPSHOTS_DIR_INO, FileType::Directory, ".".into()));
+                entries.push((ROOT_INO, FileType::Directory, "..".into()));
+                let summaries = match self.runtime.block_on(self.snapshots.list()) {
+                    Ok(v) => v,
+                    Err(_) => {
+                        reply.error(libc::EIO);
+                        return;
+                    }
+                };
+                for s in summaries {
+                    let ino = self.alloc_snapshot_ino(&s.name);
+                    entries.push((ino, FileType::Directory, s.name));
+                }
+            }
+            snap_ino if (FIRST_SNAPSHOT_INO..FIRST_BLOB_INO).contains(&snap_ino) => {
+                entries.push((snap_ino, FileType::Directory, ".".into()));
+                entries.push((SNAPSHOTS_DIR_INO, FileType::Directory, "..".into()));
+                let name = match self.ino_to_snapshot.get(&snap_ino).cloned() {
+                    Some(n) => n,
+                    None => {
+                        reply.error(libc::ENOENT);
+                        return;
+                    }
+                };
+                let manifest = match self
+                    .runtime
+                    .block_on(self.snapshots.get(&name))
+                    .ok()
+                    .flatten()
+                {
+                    Some(m) => m,
+                    None => {
+                        reply.error(libc::ENOENT);
+                        return;
+                    }
+                };
+                for id in manifest.blob_ids {
+                    let hex = id.to_hex();
+                    let ino = self.alloc_blob_ino(&hex);
                     entries.push((ino, FileType::RegularFile, hex));
                 }
             }
@@ -312,7 +449,9 @@ fn main() -> Result<()> {
     }
     let store = BlobStore::open(cli.data_dir.clone())
         .with_context(|| format!("opening blob store at {}", cli.data_dir.display()))?;
-    let fs = ClawFuse::new(store)?;
+    let snapshots = SnapshotStore::open(cli.data_dir.clone())
+        .with_context(|| format!("opening snapshot store at {}", cli.data_dir.display()))?;
+    let fs = ClawFuse::new(store, snapshots)?;
 
     let mut opts = vec![
         MountOption::RO,