From 304a68b9c63bbfc1f6e159d68e8892fc54a06067 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Tue, 29 Nov 2022 09:09:17 +1100
Subject: xfs: use iomap_valid method to detect stale cached iomaps
Now that iomap supports a mechanism to validate cached iomaps for
buffered write operations, hook it up to the XFS buffered write ops
so that we can avoid data corruptions that result from stale cached
iomaps. See:
https://lore.kernel.org/linux-xfs/20220817093627.GZ3600936@dread.disaster.area/
or the ->iomap_valid() introduction commit for exact details of the
corruption vector.
The validity cookie we store in the iomap is based on the type of
iomap we return. It is expected that the iomap->flags we set in
xfs_bmbt_to_iomap() is not perturbed by the iomap core and are
returned to us in the iomap passed via the .iomap_valid() callback.
This ensures that the validity cookie is always checking the correct
inode fork sequence numbers to detect potential changes that affect
the extent cached by the iomap.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_bmap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
(limited to 'fs/xfs/libxfs/xfs_bmap.c')
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 49d0d4ea63fc..56b9b7db38bb 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4551,7 +4551,8 @@ xfs_bmapi_convert_delalloc(
* the extent. Just return the real extent at this offset.
*/
if (!isnullstartblock(bma.got.br_startblock)) {
- xfs_bmbt_to_iomap(ip, iomap, &bma.got, 0, flags);
+ xfs_bmbt_to_iomap(ip, iomap, &bma.got, 0, flags,
+ xfs_iomap_inode_sequence(ip, flags));
*seq = READ_ONCE(ifp->if_seq);
goto out_trans_cancel;
}
@@ -4599,7 +4600,8 @@ xfs_bmapi_convert_delalloc(
XFS_STATS_INC(mp, xs_xstrat_quick);
ASSERT(!isnullstartblock(bma.got.br_startblock));
- xfs_bmbt_to_iomap(ip, iomap, &bma.got, 0, flags);
+ xfs_bmbt_to_iomap(ip, iomap, &bma.got, 0, flags,
+ xfs_iomap_inode_sequence(ip, flags));
*seq = READ_ONCE(ifp->if_seq);
if (whichfork == XFS_COW_FORK)
--
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