From: "Darrick J. Wong" djwong@kernel.org
commit c0afba9a8363f17d4efed22a8764df33389aebe8 upstream.
A reviewer was confused by the init_sa logic in this function. Upon checking the logic, I discovered that the code is imprecise. What we want to do here is check that there is an ownership record in the rmap btree for the AG that contains a btree block.
For an inode-rooted btree (e.g. the bmbt) the per-AG btree cursors have not been initialized because inode btrees can span multiple AGs. Therefore, we must initialize the per-AG btree cursors in sc->sa before proceeding. That is what init_sa controls, and hence the logic should be gated on XFS_BTREE_ROOT_IN_INODE, not XFS_BTREE_LONG_PTRS.
In practice, ROOT_IN_INODE and LONG_PTRS are coincident so this hasn't mattered. However, we're about to refactor both of those flags into separate btree_ops fields so we want this the logic to make sense afterwards.
Fixes: 858333dcf021a ("xfs: check btree block ownership with bnobt/rmapbt when scrubbing btree") Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Catherine Hoang catherine.hoang@oracle.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/scrub/btree.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/scrub/btree.c b/fs/xfs/scrub/btree.c index 1935b9ce1885..c3a9f33e5a8d 100644 --- a/fs/xfs/scrub/btree.c +++ b/fs/xfs/scrub/btree.c @@ -385,7 +385,12 @@ xchk_btree_check_block_owner( agno = xfs_daddr_to_agno(bs->cur->bc_mp, daddr); agbno = xfs_daddr_to_agbno(bs->cur->bc_mp, daddr);
- init_sa = bs->cur->bc_flags & XFS_BTREE_LONG_PTRS; + /* + * If the btree being examined is not itself a per-AG btree, initialize + * sc->sa so that we can check for the presence of an ownership record + * in the rmap btree for the AG containing the block. + */ + init_sa = bs->cur->bc_flags & XFS_BTREE_ROOT_IN_INODE; if (init_sa) { error = xchk_ag_init_existing(bs->sc, agno, &bs->sc->sa); if (!xchk_btree_xref_process_error(bs->sc, bs->cur,