Add PublishedNodes field to ListVolumes Response and wrap published_node_ids into a VolumeStatus message

Author: davidz627

csi.proto

@@ -800,8 +800,28 @@ message ListVolumesRequest {
 }
 
 message ListVolumesResponse {
+  message VolumeStatus{
+    // A list of all `node_id` of nodes that the volume in this entry
+    // is controller published on.
+    // This field is OPTIONAL. If it is not specified and the SP has
+    // the LIST_VOLUMES_PUBLISHED_NODES controller capability, the CO
+    // MAY assume the volume is not controller published to any nodes.
+    // If the field is not specified and the SP does not have the
+    // LIST_VOLUMES_PUBLISHED_NODES controller capability, the CO MUST
+    // not interpret this field.
+    // published_node_ids MAY include nodes not published to or
+    // reported by the SP. The CO MUST be resilient to that.
+    repeated string published_node_ids = 1;
+  }
+
   message Entry {
+    // This field is REQUIRED
     Volume volume = 1;
+
+    // This field is OPTIONAL. This field MUST be specified if the
+    // LIST_VOLUMES_PUBLISHED_NODES controller capability is
+    // supported.
+    VolumeStatus status = 2;
   }
 
   repeated Entry entries = 1;
@@ -884,6 +904,10 @@ message ControllerServiceCapability {
 
       // See VolumeExpansion for details.
       EXPAND_VOLUME = 9;
+
+      // Indicates the SP supports the
+      // ListVolumesResponse.entry.published_nodes field
+      LIST_VOLUMES_PUBLISHED_NODES = 10;
     }
 
     Type type = 1;