On Mon, Jan 27, 2025 at 05:12:41PM +0800, Alan Huang wrote: > When ancestor is less than IS_ANCESTOR_BITMAP, we would get an incorrect > result. > > Signed-off-by: Alan Huang <[email protected]> > --- > fs/bcachefs/snapshot.c | 5 +++-- > 1 file 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);
That's not right, if ancestor < IS_ANCESTOR_BITMAP the bitmap would still need to be initialized.
