[PATCH 5.9 170/252] xfs: revert "xfs: fix rmap key and record comparison functions"

Greg Kroah-Hartman
2020-11-23T13:09:01Z

From: Darrick J. Wong <darrick.wong@oracle.com>

[ Upstream commit eb8409071a1d47e3593cfe077107ac46853182ab ]

This reverts commit 6ff646b2ceb0eec916101877f38da0b73e3a5b7f.

Your maintainer committed a major braino in the rmap code by adding the
attr fork, bmbt, and unwritten extent usage bits into rmap record key
comparisons. While XFS uses the usage bits *in the rmap records* for
cross-referencing metadata in xfs_scrub and xfs_repair, it only needs
the owner and offset information to distinguish between reverse mappings
of the same physical extent into the data fork of a file at multiple
offsets. The other bits are not important for key comparisons for index
lookups, and never have been.

Eric Sandeen reports that this causes regressions in generic/299, so
undo this patch before it does more damage.

Reported-by: Eric Sandeen <sandeen@sandeen.net>
Fixes: 6ff646b2ceb0 ("xfs: fix rmap key and record comparison functions")
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/xfs/libxfs/xfs_rmap_btree.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index 577a66381327c..beb81c84a9375 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -243,8 +243,8 @@ xfs_rmapbt_key_diff(
else if (y > x)
return -1;

- x = be64_to_cpu(kp->rm_offset);
- y = xfs_rmap_irec_offset_pack(rec);
+ x = XFS_RMAP_OFF(be64_to_cpu(kp->rm_offset));
+ y = rec->rm_offset;
if (x > y)
return 1;
else if (y > x)
@@ -275,8 +275,8 @@ xfs_rmapbt_diff_two_keys(
else if (y > x)
return -1;

- x = be64_to_cpu(kp1->rm_offset);
- y = be64_to_cpu(kp2->rm_offset);
+ x = XFS_RMAP_OFF(be64_to_cpu(kp1->rm_offset));
+ y = XFS_RMAP_OFF(be64_to_cpu(kp2->rm_offset));
if (x > y)
return 1;
else if (y > x)
@@ -390,8 +390,8 @@ xfs_rmapbt_keys_inorder(
return 1;
else if (a > b)
return 0;
- a = be64_to_cpu(k1->rmap.rm_offset);
- b = be64_to_cpu(k2->rmap.rm_offset);
+ a = XFS_RMAP_OFF(be64_to_cpu(k1->rmap.rm_offset));
+ b = XFS_RMAP_OFF(be64_to_cpu(k2->rmap.rm_offset));
if (a <= b)
return 1;
return 0;
@@ -420,8 +420,8 @@ xfs_rmapbt_recs_inorder(
return 1;
else if (a > b)
return 0;
- a = be64_to_cpu(r1->rmap.rm_offset);
- b = be64_to_cpu(r2->rmap.rm_offset);
+ a = XFS_RMAP_OFF(be64_to_cpu(r1->rmap.rm_offset));
+ b = XFS_RMAP_OFF(be64_to_cpu(r2->rmap.rm_offset));
if (a <= b)
return 1;
return 0;
--
2.27.0