diff --git a/nova/tests/unit/virt/disk/mount/test_nbd.py b/nova/tests/unit/virt/disk/mount/test_nbd.py
index 2baea9069670..0d52c67c2613 100644
--- a/nova/tests/unit/virt/disk/mount/test_nbd.py
+++ b/nova/tests/unit/virt/disk/mount/test_nbd.py
@@ -260,6 +260,8 @@ class NbdTestCase(test.NoDBTestCase):
         mount.map_dev = fake_returns_true
 
         self.assertFalse(mount.do_mount())
+        mock_mount.assert_called_once_with(
+                None, None, tempdir, None)
 
     @mock.patch('nova.privsep.fs.nbd_connect')
     @mock.patch('nova.privsep.fs.nbd_disconnect')
diff --git a/nova/virt/disk/mount/api.py b/nova/virt/disk/mount/api.py
index 97ac6d2e2fba..a8585a0c9f51 100644
--- a/nova/virt/disk/mount/api.py
+++ b/nova/virt/disk/mount/api.py
@@ -248,7 +248,7 @@ class Mount(object):
         LOG.debug("Mount %(dev)s on %(dir)s",
                   {'dev': self.mapped_device, 'dir': self.mount_dir})
         out, err = nova.privsep.fs.mount(None, self.mapped_device,
-                                         self.mount_dir)
+                                         self.mount_dir, None)
         if err:
             self.error = _('Failed to mount filesystem: %s') % err
             LOG.debug(self.error)