[PATCH 3.16 104/136] ceph: add missing check in d_revalidate snapdir handling

[Ben Hutchings]

3.16.80-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit 1f08529c84cfecaf1261ed9b7e17fab18541c58f upstream.

We should not play with dcache without parent locked...

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
[bwh: Backported to 3.16:
 - Test ceph_mds_request::r_locked_dir
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 fs/ceph/inode.c | 1 +
 1 file changed, 1 insertion(+)

--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1260,6 +1260,7 @@ retry_lookup:
 					    req->r_request_started);
 		dout(" final dn %p\n", dn);
 	} else if (!req->r_aborted &&
+	           req->r_locked_dir &&
 		   (req->r_op == CEPH_MDS_OP_LOOKUPSNAP ||
 		    req->r_op == CEPH_MDS_OP_MKSNAP)) {
 		struct dentry *dn = req->r_dentry;