From: Darrick J. Wong Date: Thu, 16 Sep 2021 19:26:46 +0000 (-0700) Subject: xfs: fix maxlevels comparisons in the btree staging code X-Git-Tag: block-5.16-2021-11-13~85^2~40 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=78e8ec83a404d63dcc86b251f42e4ee8aff27465;p=linux-block.git xfs: fix maxlevels comparisons in the btree staging code 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 Reviewed-by: Chandan Babu R Reviewed-by: Christoph Hellwig --- 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;