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 --- 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;