diff options
| author | Alan Huang <mmpgouride@gmail.com> | 2025-01-27 17:12:41 +0800 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2025-02-07 14:49:49 -0500 |
| commit | 24aef400a5ddac8d94a8e787e2f1b9fe81eb915c (patch) | |
| tree | 9719877e4f9eb0409299a56a818d4ec79ab51c5e | |
| parent | 8deb148cb5e9124e3138c5aee77c7933f1479d5e (diff) | |
bcachefs: Fix subtraction underflow
When ancestor is less than IS_ANCESTOR_BITMAP, we would get an incorrect
result.
Signed-off-by: Alan Huang <mmpgouride@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
| -rw-r--r-- | fs/bcachefs/snapshot.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/bcachefs/snapshot.c b/fs/bcachefs/snapshot.c index c54091a28909..ede0b480e7d4 100644 --- a/fs/bcachefs/snapshot.c +++ b/fs/bcachefs/snapshot.c @@ -146,8 +146,9 @@ bool __bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor) goto out; } - while (id && id < ancestor - IS_ANCESTOR_BITMAP) - id = get_ancestor_below(t, id, ancestor); + if (likely(ancestor >= IS_ANCESTOR_BITMAP)) + while (id && id < ancestor - IS_ANCESTOR_BITMAP) + id = get_ancestor_below(t, id, ancestor); ret = id && id < ancestor ? test_ancestor_bitmap(t, id, ancestor) |