[PATCH 5.4 052/118] NFSv4.2: error out when relink swapfile

[Greg Kroah-Hartman]

From: Murphy Zhou <jencce.kernel@xxxxxxxxx>

[ Upstream commit f5fdf1243fb750598b46305dd03c553949cfa14f ]

This fixes xfstests generic/356 failure on NFSv4.2.

Signed-off-by: Murphy Zhou <jencce.kernel@xxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/nfs/nfs4file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 54f1c1f626fc5..fb55c04cdc6bd 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -210,6 +210,9 @@ static loff_t nfs42_remap_file_range(struct file *src_file, loff_t src_off,
 	if (remap_flags & ~REMAP_FILE_ADVISORY)
 		return -EINVAL;
 
+	if (IS_SWAPFILE(dst_inode) || IS_SWAPFILE(src_inode))
+		return -ETXTBSY;
+
 	/* check alignment w.r.t. clone_blksize */
 	ret = -EINVAL;
 	if (bs) {
-- 
2.20.1