From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 29 Oct 2019 13:53:29 +0000
Subject: ceph: add missing check in d_revalidate snapdir handling
Git-commit: 1f08529c84cfecaf1261ed9b7e17fab18541c58f
Patch-mainline: v5.4-rc7
References: bsc#1157183

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

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Acked-by: Luis Henriques <lhenriques@suse.com>
---
 fs/ceph/inode.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1398,6 +1398,7 @@ 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 inode *dir = req->r_parent;