bcachefs: __lookup_dirent() works in snapshot, not subvol

Add a new helper, bch2_hash_lookup_in_snapshot(), for when we're not
operating in a subvolume and already have a snapshot ID, and then use it
in lookup_lostfound() -> __lookup_dirent().

This is a bugfix - lookup_lostfound() doesn't take a subvolume ID, we
were passing a nonsense subvolume ID before, and don't have one to pass
since we may be operating in an interior snapshot node that doesn't have
a subvolume ID.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index 4f0ecd60567570b7364cef517225ea0e3dfa5575..6a760777bafb06d08b449ee0db4308a77b54b11e 100644 (file)
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -119,22 +119,19 @@ static int lookup_inode(struct btree_trans *trans, u64 inode_nr,
        if (!ret)
                *snapshot = iter.pos.snapshot;
 err:
-       bch_err_msg(trans->c, ret, "fetching inode %llu:%u", inode_nr, *snapshot);
        bch2_trans_iter_exit(trans, &iter);
        return ret;
 }
 
-static int __lookup_dirent(struct btree_trans *trans,
+static int lookup_dirent_in_snapshot(struct btree_trans *trans,
                           struct bch_hash_info hash_info,
                           subvol_inum dir, struct qstr *name,
-                          u64 *target, unsigned *type)
+                          u64 *target, unsigned *type, u32 snapshot)
 {
        struct btree_iter iter;
        struct bkey_s_c_dirent d;
-       int ret;
-
-       ret = bch2_hash_lookup(trans, &iter, bch2_dirent_hash_desc,
-                              &hash_info, dir, name, 0);
+       int ret = bch2_hash_lookup_in_snapshot(trans, &iter, bch2_dirent_hash_desc,
+                              &hash_info, dir, name, 0, snapshot);
        if (ret)
                return ret;
 
@@ -225,15 +222,16 @@ static int lookup_lostfound(struct btree_trans *trans, u32 snapshot,
 
        struct bch_inode_unpacked root_inode;
        struct bch_hash_info root_hash_info;
-       ret = lookup_inode(trans, root_inum.inum, &root_inode, &snapshot);
+       u32 root_inode_snapshot = snapshot;
+       ret = lookup_inode(trans, root_inum.inum, &root_inode, &root_inode_snapshot);
        bch_err_msg(c, ret, "looking up root inode");
        if (ret)
                return ret;
 
        root_hash_info = bch2_hash_info_init(c, &root_inode);
 
-       ret = __lookup_dirent(trans, root_hash_info, root_inum,
-                             &lostfound_str, &inum, &d_type);
+       ret = lookup_dirent_in_snapshot(trans, root_hash_info, root_inum,
+                             &lostfound_str, &inum, &d_type, snapshot);
        if (bch2_err_matches(ret, ENOENT))
                goto create_lostfound;
 
@@ -250,7 +248,10 @@ static int lookup_lostfound(struct btree_trans *trans, u32 snapshot,
         * The bch2_check_dirents pass has already run, dangling dirents
         * shouldn't exist here:
         */
-       return lookup_inode(trans, inum, lostfound, &snapshot);
+       ret = lookup_inode(trans, inum, lostfound, &snapshot);
+       bch_err_msg(c, ret, "looking up lost+found %llu:%u in (root inode %llu, snapshot root %u)",
+                   inum, snapshot, root_inum.inum, bch2_snapshot_root(c, snapshot));
+       return ret;
 
 create_lostfound:
        /*

diff --git a/fs/bcachefs/str_hash.h b/fs/bcachefs/str_hash.h
index 89fdb7c21134ebbb6c145a88ed5b1943ab54588a..fcaa5a888744881a4f6c37dd77fbd8cf73b2f4d0 100644 (file)
--- a/fs/bcachefs/str_hash.h
+++ b/fs/bcachefs/str_hash.h
@@ -160,21 +160,16 @@ static inline bool is_visible_key(struct bch_hash_desc desc, subvol_inum inum, s
 }
 
 static __always_inline int
-bch2_hash_lookup(struct btree_trans *trans,
+bch2_hash_lookup_in_snapshot(struct btree_trans *trans,
                 struct btree_iter *iter,
                 const struct bch_hash_desc desc,
                 const struct bch_hash_info *info,
                 subvol_inum inum, const void *key,
-                unsigned flags)
+                unsigned flags, u32 snapshot)
 {
        struct bkey_s_c k;
-       u32 snapshot;
        int ret;
 
-       ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
-       if (ret)
-               return ret;
-
        for_each_btree_key_upto_norestart(trans, *iter, desc.btree_id,
                           SPOS(inum.inum, desc.hash_key(info, key), snapshot),
                           POS(inum.inum, U64_MAX),
@@ -194,6 +189,19 @@ bch2_hash_lookup(struct btree_trans *trans,
        return ret ?: -BCH_ERR_ENOENT_str_hash_lookup;
 }
 
+static __always_inline int
+bch2_hash_lookup(struct btree_trans *trans,
+                struct btree_iter *iter,
+                const struct bch_hash_desc desc,
+                const struct bch_hash_info *info,
+                subvol_inum inum, const void *key,
+                unsigned flags)
+{
+       u32 snapshot;
+       return  bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot) ?:
+               bch2_hash_lookup_in_snapshot(trans, iter, desc, info, inum, key, flags, snapshot);
+}
+
 static __always_inline int
 bch2_hash_hole(struct btree_trans *trans,
               struct btree_iter *iter,