[PATCH 01/15] xfs: fix maxlevels comparisons in the btree staging code
From: "Darrick J. Wong" <djwong@kernel.org>
Date: 2021-09-24 01:26:19
Subsystem:
filesystems (vfs and infrastructure), the rest, xfs filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, Carlos Maiolino
From: Darrick J. Wong <djwong@kernel.org> 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 <redacted> Reviewed-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/libxfs/xfs_btree_staging.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_btree_staging.c b/fs/xfs/libxfs/xfs_btree_staging.c
index ac9e80152b5c..89c8a1498df1 100644
--- 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;