From: Yan, Zheng <zyan@redhat.com>
Date: Mon, 11 Feb 2019 07:18:52 +0000 (+0800)
Subject: ceph: avoid repeatedly adding inode to mdsc->snap_flush_list
X-Git-Tag: v4.14.104~66
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=eddbdfe4a2c4db0760f5d134e9f97c6bdcc975b6;p=users%2Fjedix%2Flinux-maple.git

ceph: avoid repeatedly adding inode to mdsc->snap_flush_list

commit 04242ff3ac0abbaa4362f97781dac268e6c3541a upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index 8a2ca41e4b97c..9b6207c84b689 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -616,7 +616,8 @@ int __ceph_finish_cap_snap(struct ceph_inode_info *ci,
 	     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 */
 }