add block storage v1 client
diff --git a/openstack/client.go b/openstack/client.go
index eeeb809..b916dd9 100644
--- a/openstack/client.go
+++ b/openstack/client.go
@@ -313,3 +313,13 @@
 	}
 	return &gophercloud.ServiceClient{Provider: client, Endpoint: url}, nil
 }
+
+// NewBlockStorageV1 creates a ServiceClient that may be used to access the v1 block storage service.
+func NewBlockStorageV1(client *gophercloud.ProviderClient, eo gophercloud.EndpointOpts) (*gophercloud.ServiceClient, error) {
+	eo.ApplyDefaults("volume")
+	url, err := client.EndpointLocator(eo)
+	if err != nil {
+		return nil, err
+	}
+	return &gophercloud.ServiceClient{Provider: client, Endpoint: url}, nil
+}