[PATCH 4.19 032/125] ceph: add missing check in d_revalidate snapdir handling

[Greg Kroah-Hartman]

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit 1f08529c84cfecaf1261ed9b7e17fab18541c58f upstream.

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

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/ceph/inode.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1399,6 +1399,7 @@ retry_lookup:
 		dout(" final dn %p\n", dn);
 	} else if ((req->r_op == CEPH_MDS_OP_LOOKUPSNAP ||
 		    req->r_op == CEPH_MDS_OP_MKSNAP) &&
+	           test_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags) &&
 		   !test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
 		struct dentry *dn = req->r_dentry;
 		struct inode *dir = req->r_parent;