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xfs: fix maxlevels comparisons in the btree staging code

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[ Upstream commit 78e8ec83a404d63dcc86b251f42e4ee8aff27465 ]

The btree geometry computation function has an off-by-one error in that
it does not allow maximally tall btrees (nlevels == XFS_BTREE_MAXLEVELS).
This can result in repairs failing unnecessarily on very fragmented
filesystems.  Subsequent patches to remove MAXLEVELS usage in favor of
the per-btree type computations will make this a much more likely
occurrence.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Darrick J. Wong 2022-07-21 14:36:05 -07:00 committed by Greg Kroah-Hartman
parent cf719adb6f
commit 67cb74213a
1 changed files with 2 additions and 2 deletions
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4
fs/xfs/libxfs/xfs_btree_staging.c
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@ -662,7 +662,7 @@ xfs_btree_bload_compute_geometry(
xfs_btree_bload_ensure_slack(cur, &bbl->node_slack, 1);
bbl->nr_records = nr_this_level = nr_records;
for (cur->bc_nlevels = 1; cur->bc_nlevels < XFS_BTREE_MAXLEVELS;) {
for (cur->bc_nlevels = 1; cur->bc_nlevels <= XFS_BTREE_MAXLEVELS;) {
uint64_t level_blocks;
uint64_t dontcare64;
unsigned int level = cur->bc_nlevels - 1;
@ -724,7 +724,7 @@ xfs_btree_bload_compute_geometry(
nr_this_level = level_blocks;
}
if (cur->bc_nlevels == XFS_BTREE_MAXLEVELS)
if (cur->bc_nlevels > XFS_BTREE_MAXLEVELS)
return -EOVERFLOW;
bbl->btree_height = cur->bc_nlevels;