ceph: add missing locking to protect i_snap_realm_item during split
All ci->i_snap_realm_item/realm->inodes_with_caps manipulation should be
protected by realm->inodes_with_caps_lock. This bug would have only bit
us in a rare race with a realm split (during some snap creations).
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index bf2a5f3..8a43bc8 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -818,7 +818,9 @@
* queued (again) by ceph_update_snap_trace()
* below. Queue it _now_, under the old context.
*/
+ spin_lock(&realm->inodes_with_caps_lock);
list_del_init(&ci->i_snap_realm_item);
+ spin_unlock(&realm->inodes_with_caps_lock);
spin_unlock(&inode->i_lock);
ceph_queue_cap_snap(ci,
