address review feedback

Author: James DeFelice

csi.proto

@@ -250,20 +250,14 @@ message VolumeInfo {
   string id = 2;
 
   // Attributes reflect static properties of a volume and MUST be passed
-  // to volume validation and publishing calls. Attributes MAY NOT
-  // uniquely identify a volume. A volume uniquely identified by `id`
-  // SHALL always report the same attributes. This field is REQUIRED.
-  Attributes attributes = 3;
-}
-
-// Attributes are generally specific to the system that generated them:
-// CO-generated attributes SHALL be opaque to a plugin, and plugin-
-// generated attributes SHALL be opaque to a CO. Attributes SHALL NOT
-// be mutable and SHALL be safe for any party to cache. Attributes
-// SHOULD NOT contain sensitive information.
-message Attributes {
-  // This field is OPTIONAL.
-  map<string,string> values = 1;
+  // to volume validation and publishing calls.
+  // Attributes SHALL be opaque to a CO. Attributes SHALL NOT be mutable
+  // and SHALL be safe for the CO to cache. Attributes SHOULD NOT
+  // contain sensitive information. Attributes MAY NOT uniquely identify
+  // a volume. A volume uniquely identified by `id` SHALL always report
+  // the same attributes. This field is OPTIONAL and when present MUST
+  // be passed to volume validation and publishing calls.
+  map<string,string> attributes = 3;
 }
 
 // A standard way to encode credential data. The total bytes of the
@@ -335,8 +329,9 @@ message ControllerPublishVolumeRequest {
   Credentials user_credentials = 6;
 
   // Attributes of the volume to be used on a node. This field is
-  // REQUIRED.
-  Attributes volume_attributes = 7;
+  // OPTIONAL and MUST match the attributes of the VolumeInfo identified
+  // by `volume_id`.
+  map<string,string> volume_attributes = 7;
 }
 
 message ControllerPublishVolumeResponse {
@@ -410,8 +405,9 @@ message ValidateVolumeCapabilitiesRequest {
   // specified below are supported. This field is REQUIRED.
   repeated VolumeCapability volume_capabilities = 3;
 
-  // Attributes of the volume to check. This field is REQUIRED.
-  Attributes volume_attributes = 4;
+  // Attributes of the volume to check. This field is OPTIONAL and MUST
+  // match the attributes of the VolumeInfo identified by `volume_id`.
+  map<string,string> volume_attributes = 4;
 }
 
 message ValidateVolumeCapabilitiesResponse {
@@ -584,8 +580,10 @@ message NodePublishVolumeRequest {
   // request. This field is OPTIONAL.
   Credentials user_credentials = 7;
 
-  // Attributes of the volume to publish. This field is REQUIRED.
-  Attributes volume_attributes = 8;
+  // Attributes of the volume to publish. This field is OPTIONAL and
+  // MUST match the attributes of the VolumeInfo identified by
+  // `volume_id`.
+  map<string,string> volume_attributes = 8;
 }
 
 message NodePublishVolumeResponse {