[PATCH 1/5] xfs: cancel COW blocks before swapext

[Christoph Hellwig <hch@lst.de>]

We need to make sure we have no outstanding COW blocks before we swap
extents, as there is nothing preventing us from having COW preallocations
on an inode that swapext is called on.  That case can easily be
reproduced by the upcoming always_cow mode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_bmap_util.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 414dbc31139c..e0e9cbc98ccd 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1515,6 +1515,12 @@ xfs_swap_extent_flush(
 		return error;
 	truncate_pagecache_range(VFS_I(ip), 0, -1);
 
+	if (xfs_inode_has_cow_data(ip)) {
+		error = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, true);
+		if (error)
+			return error;
+	}
+
 	/* Verify O_DIRECT for ftmp */
 	if (VFS_I(ip)->i_mapping->nrpages)
 		return -EINVAL;
-- 
2.18.0