Address review comments

Author: xing-yang

csi.proto

@@ -96,8 +96,8 @@ service Controller {
   rpc ControllerExpandVolume (ControllerExpandVolumeRequest)
     returns (ControllerExpandVolumeResponse) {}
 
-  rpc GetVolume (GetVolumeRequest)
-    returns (GetVolumeResponse) {
+  rpc ControllerGetVolume (ControllerGetVolumeRequest)
+    returns (ControllerGetVolumeResponse) {
         option (alpha_method) = true;
     }
 }
@@ -855,10 +855,11 @@ message ListVolumesResponse {
     // reported by the SP. The CO MUST be resilient to that.
     repeated string published_node_ids = 1;
 
-    // volume_condition shows error conditions reported by the SP.
+    // volume_condition shows information about the current health of
+    // the volume.
+    // This field is OPTIONAL.
     // This field MUST be specified if the
     // LIST_VOLUMES_VOLUME_CONDITION controller capability is supported.
-    // This field is OPTIONAL.
     VolumeCondition volume_condition = 2 [(alpha_field) = true];
   }
 
@@ -882,31 +883,34 @@ message ListVolumesResponse {
   // An empty string is equal to an unspecified field value.
   string next_token = 2;
 }
-message GetVolumeRequest {
+message ControllerGetVolumeRequest {
   option (alpha_message) = true;
 
   // Identity information for a specific volume. This field is
-  // REQUIRED. GetVolume will return with current volume information.
+  // REQUIRED. ControllerGetVolume will return with current
+  // volume information.
   string volume_id = 1;
 }
 
-message GetVolumeResponse {
+message ControllerGetVolumeResponse {
   option (alpha_message) = true;
 
   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 GET_VOLUME_PUBLISHED_NODES controller capability, the CO
+    // the PUBLISH_UNPUBLISH_VOLUME 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
-    // GET_VOLUME_PUBLISHED_NODES controller capability, the CO MUST
+    // PUBLISH_UNPUBLISH_VOLUME 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;
 
-    // volume_condition shows error conditions reported by the SP.
+    // volume_condition shows information about the current health of
+    // the volume.
+    // This field is OPTIONAL.
     // This field MUST be specified if the
     // GET_VOLUME_VOLUME_CONDITION controller capability is supported.
     VolumeCondition volume_condition = 2;
@@ -995,19 +999,14 @@ message ControllerServiceCapability {
       LIST_VOLUMES_PUBLISHED_NODES = 10;
 
       // Indicates the SP supports the
-      // ListVolumesResponse.entry.volume_condition field
-      LIST_VOLUMES_VOLUME_CONDITION = 11 [(alpha_enum_value) = true];
+      // ListVolumesResponse.entry.status.volume_condition field
+      // if SP also supports LIST_VOLUMES capability, or supports the
+      // ControllerGetVolumeResponse.status.volume_condition field
+      // if SP also supports GET_VOLUME capability
+      VOLUME_CONDITION = 11 [(alpha_enum_value) = true];
 
-      // Indicates the SP supports the GetVolume RPC
+      // Indicates the SP supports the ControllerGetVolume RPC
       GET_VOLUME = 12 [(alpha_enum_value) = true];
-
-      // Indicates the SP supports the
-      // GetVolumeResponse.volume_condition field
-      GET_VOLUME_VOLUME_CONDITION = 13 [(alpha_enum_value) = true];
-
-      // Indicates the SP supports the
-      // GetVolumesResponse.published_node_ids field
-      GET_VOLUME_PUBLISHED_NODES = 14 [(alpha_enum_value) = true];
     }
 
     Type type = 1;
@@ -1367,8 +1366,7 @@ message VolumeCondition {
   option (alpha_message) = true;
 
   // Indicates the health condition of a volume is not normal.
-  // This field is OPTIONAL. If not present, it indicates the
-  // health condition is unknown.
+  // This field is REQUIRED.
   .google.protobuf.BoolValue abnormal = 1;
 
   // The message describing the health condition of the volume.