From: "Yan, Zheng" <zyan@redhat.com>

Date: Mon, 11 Feb 2019 15:18:52 +0800

Subject: ceph: avoid repeatedly adding inode to mdsc->snap_flush_list

Git-commit: 04242ff3ac0abbaa4362f97781dac268e6c3541a

Patch-mainline: v5.0-rc8

References: bsc#1126790

Otherwise, mdsc->snap_flush_list may get corrupted.

Cc: stable@vger.kernel.org

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>

Reviewed-by: Ilya Dryomov <idryomov@gmail.com>

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

Acked-by: Luis Henriques <lhenriques@suse.com>

---

 fs/ceph/snap.c |    3 ++-

 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/ceph/snap.c

+++ b/fs/ceph/snap.c

@@ -615,7 +615,8 @@ int __ceph_finish_cap_snap(struct ceph_i

 	     capsnap->size);

 	spin_lock(&mdsc->snap_flush_lock);

-	list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);

+	if (list_empty(&ci->i_snap_flush_item))

+		list_add_tail(&ci->i_snap_flush_item, &mdsc->snap_flush_list);

 	spin_unlock(&mdsc->snap_flush_lock);

 	return 1;  /* caller may want to ceph_flush_snaps */

 }