ceph: fix dentry leak in ceph_readdir_prepopulate

[ Upstream commit c58f450b ]
Signed-off-by: N"Yan, Zheng" <zyan@redhat.com>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/ceph/inode.c

@@ -1694,7 +1694,6 @@ int ceph_readdir_prepopulate(struct ceph_mds_request *req,
 			if (IS_ERR(realdn)) {
 				err = PTR_ERR(realdn);
 				d_drop(dn);
-				dn = NULL;
 				goto next_item;
 			}
 			dn = realdn;