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From: "Darrick J. Wong" <djwong@kernel.org>
To: djwong@kernel.org, chandan.babu@oracle.com, chandanrlinux@gmail.com
Cc: Christoph Hellwig <hch@lst.de>, linux-xfs@vger.kernel.org
Subject: [PATCH 01/15] xfs: fix maxlevels comparisons in the btree staging code
Date: Thu, 23 Sep 2021 18:26:17 -0700	[thread overview]
Message-ID: <163244677758.2701302.11176093546368019785.stgit@magnolia> (raw)
In-Reply-To: <163244677169.2701302.12882919857957905332.stgit@magnolia>

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 <chandan.babu@oracle.com>
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;


  reply	other threads:[~2021-09-24  1:26 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-24  1:26 [PATCHSET RFC v2 chandan 00/15] xfs: support dynamic btree cursor height Darrick J. Wong
2021-09-24  1:26 ` Darrick J. Wong [this message]
2021-09-24  1:26 ` [PATCH 02/15] xfs: remove xfs_btree_cur_t typedef Darrick J. Wong
2021-09-24  1:26 ` [PATCH 03/15] xfs: don't allocate scrub contexts on the stack Darrick J. Wong
2021-09-24  1:26 ` [PATCH 04/15] xfs: don't track firstrec/firstkey separately in xchk_btree Darrick J. Wong
2021-09-24  1:26 ` [PATCH 05/15] xfs: dynamically allocate btree scrub context structure Darrick J. Wong
2021-09-24  1:26 ` [PATCH 06/15] xfs: stricter btree height checking when looking for errors Darrick J. Wong
2021-09-24  1:26 ` [PATCH 07/15] xfs: stricter btree height checking when scanning for btree roots Darrick J. Wong
2021-09-24  1:26 ` [PATCH 08/15] xfs: check that bc_nlevels never overflows Darrick J. Wong
2021-09-24  1:27 ` [PATCH 09/15] xfs: support dynamic btree cursor heights Darrick J. Wong
2021-09-24  1:27 ` [PATCH 10/15] xfs: refactor btree cursor allocation function Darrick J. Wong
2021-09-24  1:27 ` [PATCH 11/15] xfs: encode the max btree height in the cursor Darrick J. Wong
2021-09-24  1:27 ` [PATCH 12/15] xfs: dynamically allocate cursors based on maxlevels Darrick J. Wong
2021-09-24  1:27 ` [PATCH 13/15] xfs: compute actual maximum btree height for critical reservation calculation Darrick J. Wong
2021-09-24  1:27 ` [PATCH 14/15] xfs: compute the maximum height of the rmap btree when reflink enabled Darrick J. Wong
2021-09-24  1:27 ` [PATCH 15/15] xfs: kill XFS_BTREE_MAXLEVELS Darrick J. Wong

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