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authorChandan Babu R <chandanrlinux@gmail.com>2021-01-22 16:48:14 -0800
committerDarrick J. Wong <djwong@kernel.org>2021-01-22 16:54:48 -0800
commit5f1d5bbfb2e674052a9fe542f53678978af20770 (patch)
tree3dd04de39ef9bed596a3a78bd4c098692b1476a6 /fs/xfs/xfs_reflink.c
parentc442f3086d5a108b7ff086c8ade1923a8f389db5 (diff)
downloadlinux-5f1d5bbfb2e674052a9fe542f53678978af20770.tar.gz
xfs: Check for extent overflow when moving extent from cow to data fork
Moving an extent to data fork can cause a sub-interval of an existing
extent to be unmapped. This will increase extent count by 1. Mapping in
the new extent can increase the extent count by 1 again i.e.
 | Old extent | New extent | Old extent |
Hence number of extents increases by 2.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/xfs/xfs_reflink.c')
-rw-r--r--fs/xfs/xfs_reflink.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 6fa05fb78189..ca0ac1426d74 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -628,6 +628,11 @@ xfs_reflink_end_cow_extent(
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	xfs_trans_ijoin(tp, ip, 0);
 
+	error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK,
+			XFS_IEXT_REFLINK_END_COW_CNT);
+	if (error)
+		goto out_cancel;
+
 	/*
 	 * In case of racing, overlapping AIO writes no COW extents might be
 	 * left by the time I/O completes for the loser of the race.  In that