[PATCH] xfs: only cancel cow blocks when truncating the data fork

[PATCH] xfs: only cancel cow blocks when truncating the data fork

[Darrick J. Wong]

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

In xfs_itruncate_extents, only cancel cow blocks and clear the reflink
flag if we were asked to truncate the data fork.  Attr fork blocks
cannot be shared, so this makes no sense.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_inode.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index e7907d2..383258e 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1611,13 +1611,15 @@ xfs_itruncate_extents(
 			goto out;
 	}
 
-	/* Remove all pending CoW reservations. */
-	error = xfs_reflink_cancel_cow_blocks(ip, &tp, first_unmap_block,
-			last_block, true);
-	if (error)
-		goto out;
+	if (whichfork == XFS_DATA_FORK) {
+		/* Remove all pending CoW reservations. */
+		error = xfs_reflink_cancel_cow_blocks(ip, &tp,
+				first_unmap_block, last_block, true);
+		if (error)
+			goto out;
 
-	xfs_itruncate_clear_reflink_flags(ip);
+		xfs_itruncate_clear_reflink_flags(ip);
+	}
 
 	/*
 	 * Always re-log the inode so that our permanent transaction can keep

Re: [PATCH] xfs: only cancel cow blocks when truncating the data fork

[Christoph Hellwig]

On Mon, Apr 09, 2018 at 10:13:57PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> In xfs_itruncate_extents, only cancel cow blocks and clear the reflink
> flag if we were asked to truncate the data fork.  Attr fork blocks
> cannot be shared, so this makes no sense.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>