Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.15 021/201] xfs: fix maxlevels comparisons in the btree staging code | Date | Wed, 27 Jul 2022 18:08:45 +0200 |
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From: "Darrick J. Wong" <djwong@kernel.org>
[ 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> --- fs/xfs/libxfs/xfs_btree_staging.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/xfs/libxfs/xfs_btree_staging.c +++ b/fs/xfs/libxfs/xfs_btree_staging.c @@ -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;
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