Re: [PATCH 09/14] xfs: fix maxlevels comparisons in the btree staging code
From: Chandan Babu R <hidden>
Date: 2021-09-20 10:11:21
On 18 Sep 2021 at 06:59, Darrick J. Wong wrote:
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.
Looks good. Reviewed-by: Chandan Babu R <redacted>
quoted hunk ↗ jump to hunk
Signed-off-by: Darrick J. Wong <djwong@kernel.org> --- 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 26143297bb7b..cc56efc2b90a 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;@@ -726,7 +726,7 @@ 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;
-- chandan