list volumes
diff --git a/openstack/blockstorage/v1/volumes/volumes.go b/openstack/blockstorage/v1/volumes/volumes.go
index 741e4bf..8120863 100644
--- a/openstack/blockstorage/v1/volumes/volumes.go
+++ b/openstack/blockstorage/v1/volumes/volumes.go
@@ -16,5 +16,6 @@
 	Size                int
 }
 type CreateOpts map[string]interface{}
+type ListOpts map[string]bool
 type GetOpts map[string]string
 type DeleteOpts map[string]string