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From: "Darrick J. Wong" <djwong@kernel.org>
To: djwong@kernel.org, chandan.babu@oracle.com, chandanrlinux@gmail.com
Cc: linux-xfs@vger.kernel.org
Subject: [PATCH 09/14] xfs: fix maxlevels comparisons in the btree staging code
Date: Fri, 17 Sep 2021 18:29:59 -0700	[thread overview]
Message-ID: <163192859919.416199.9790046292707106095.stgit@magnolia> (raw)
In-Reply-To: <163192854958.416199.3396890438240296942.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>
---
 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;


  parent reply	other threads:[~2021-09-18  1:30 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-18  1:29 [PATCHSET RFC chandan 00/14] xfs: support dynamic btree cursor height Darrick J. Wong
2021-09-18  1:29 ` [PATCH 01/14] xfs: remove xfs_btree_cur_t typedef Darrick J. Wong
2021-09-20  9:53   ` Chandan Babu R
2021-09-21  8:36   ` Christoph Hellwig
2021-09-18  1:29 ` [PATCH 02/14] xfs: don't allocate scrub contexts on the stack Darrick J. Wong
2021-09-20  9:53   ` Chandan Babu R
2021-09-20 17:39     ` Darrick J. Wong
2021-09-21  8:39   ` Christoph Hellwig
2021-09-18  1:29 ` [PATCH 03/14] xfs: dynamically allocate btree scrub context structure Darrick J. Wong
2021-09-20  9:53   ` Chandan Babu R
2021-09-21  8:43   ` Christoph Hellwig
2021-09-22 16:17     ` Darrick J. Wong
2021-09-18  1:29 ` [PATCH 04/14] xfs: stricter btree height checking when looking for errors Darrick J. Wong
2021-09-20  9:54   ` Chandan Babu R
2021-09-18  1:29 ` [PATCH 05/14] xfs: stricter btree height checking when scanning for btree roots Darrick J. Wong
2021-09-20  9:54   ` Chandan Babu R
2021-09-18  1:29 ` [PATCH 06/14] xfs: check that bc_nlevels never overflows Darrick J. Wong
2021-09-20  9:54   ` Chandan Babu R
2021-09-21  8:44   ` Christoph Hellwig
2021-09-18  1:29 ` [PATCH 07/14] xfs: support dynamic btree cursor heights Darrick J. Wong
2021-09-20  9:55   ` Chandan Babu R
2021-09-21  8:49   ` Christoph Hellwig
2021-09-18  1:29 ` [PATCH 08/14] xfs: refactor btree cursor allocation function Darrick J. Wong
2021-09-20  9:55   ` Chandan Babu R
2021-09-21  8:53   ` Christoph Hellwig
2021-09-18  1:29 ` Darrick J. Wong [this message]
2021-09-20  9:55   ` [PATCH 09/14] xfs: fix maxlevels comparisons in the btree staging code Chandan Babu R
2021-09-21  8:56   ` Christoph Hellwig
2021-09-22 15:59     ` Darrick J. Wong
2021-09-18  1:30 ` [PATCH 10/14] xfs: encode the max btree height in the cursor Darrick J. Wong
2021-09-20  9:55   ` Chandan Babu R
2021-09-21  8:57   ` Christoph Hellwig
2021-09-18  1:30 ` [PATCH 11/14] xfs: dynamically allocate cursors based on maxlevels Darrick J. Wong
2021-09-20  9:56   ` Chandan Babu R
2021-09-20 23:06   ` Dave Chinner
2021-09-20 23:36     ` Dave Chinner
2021-09-21  9:03     ` Christoph Hellwig
2021-09-22 18:55       ` Darrick J. Wong
2021-09-22 17:38     ` Darrick J. Wong
2021-09-22 23:10       ` Dave Chinner
2021-09-23  1:58         ` Darrick J. Wong
2021-09-23  5:56           ` Chandan Babu R
2021-09-18  1:30 ` [PATCH 12/14] xfs: compute actual maximum btree height for critical reservation calculation Darrick J. Wong
2021-09-20  9:56   ` Chandan Babu R
2021-09-18  1:30 ` [PATCH 13/14] xfs: compute the maximum height of the rmap btree when reflink enabled Darrick J. Wong
2021-09-20  9:56   ` Chandan Babu R
2021-09-18  1:30 ` [PATCH 14/14] xfs: kill XFS_BTREE_MAXLEVELS Darrick J. Wong
2021-09-20  9:57   ` Chandan Babu R

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