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xfs: fix imprecise logic in xchk_btree_check_block_owner

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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>
This commit is contained in:
Darrick J. Wong 2024-02-22 12:34:13 -08:00
parent f9e325bf61
commit c0afba9a83
1 changed files with 6 additions and 1 deletions
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7
fs/xfs/scrub/btree.c
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@ -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,