Add new error

pkg/controller/volume/persistentvolume/controller.go

@@ -1076,11 +1076,20 @@ func (ctrl *PersistentVolumeController) deleteVolumeOperation(arg interface{}) {
 	if err != nil {
 		// Delete failed, update the volume and emit an event.
 		glog.V(3).Infof("deletion of volume %q failed: %v", volume.Name, err)
-		if _, err = ctrl.updateVolumePhaseWithEvent(volume, api.VolumeFailed, api.EventTypeWarning, "VolumeFailedDelete", err.Error()); err != nil {
-			glog.V(4).Infof("deleteVolumeOperation [%s]: failed to mark volume as failed: %v", volume.Name, err)
-			// Save failed, retry on the next deletion attempt
-			return
+		if vol.IsDeletedVolumeInUse(err) {
+			// The plugin needs more time, don't mark the volume as Failed
+			// and send Normal event only
+			ctrl.eventRecorder.Event(volume, api.EventTypeNormal, "VolumeDelete", err.Error())
+		} else {
+			// The plugin failed, mark the volume as Failed and send Warning
+			// event
+			if _, err = ctrl.updateVolumePhaseWithEvent(volume, api.VolumeFailed, api.EventTypeWarning, "VolumeFailedDelete", err.Error()); err != nil {
+				glog.V(4).Infof("deleteVolumeOperation [%s]: failed to mark volume as failed: %v", volume.Name, err)
+				// Save failed, retry on the next deletion attempt
+				return
+			}
 		}
+
 		// Despite the volume being Failed, the controller will retry deleting
 		// the volume in every syncVolume() call.
 		return
@@ -1174,7 +1183,7 @@ func (ctrl *PersistentVolumeController) doDeleteVolume(volume *api.PersistentVol
 
 	if err = deleter.Delete(); err != nil {
 		// Deleter failed
-		return false, fmt.Errorf("Delete of volume %q failed: %v", volume.Name, err)
+		return false, err
 	}
 
 	glog.V(2).Infof("volume %q deleted", volume.Name)

pkg/volume/volume.go

@@ -129,6 +129,12 @@ type Provisioner interface {
 type Deleter interface {
 	Volume
 	// This method should block until completion.
+	// deletedVolumeInUseError returned from this function will not be reported
+	// as error and it will be sent as "Info" event to the PV being deleted. The
+	// volume controller will retry deleting the volume in the next periodic
+	// sync. This can be used to postpone deletion of a volume that is being
+	// dettached from a node. Deletion of such volume would fail anyway and such
+	// error would confuse users.
 	Delete() error
 }
 
@@ -171,6 +177,31 @@ type Detacher interface {
 	UnmountDevice(deviceMountPath string) error
 }
 
+// NewDeletedVolumeInUseError returns a new instance of DeletedVolumeInUseError
+// error.
+func NewDeletedVolumeInUseError(message string) error {
+	return deletedVolumeInUseError(message)
+}
+
+type deletedVolumeInUseError string
+
+var _ error = deletedVolumeInUseError("")
+
+// IsDeletedVolumeInUse returns true if an error returned from Delete() is
+// deletedVolumeInUseError
+func IsDeletedVolumeInUse(err error) bool {
+	switch err.(type) {
+	case deletedVolumeInUseError:
+		return true
+	default:
+		return false
+	}
+}
+
+func (err deletedVolumeInUseError) Error() string {
+	return string(err)
+}
+
 func RenameDirectory(oldPath, newName string) (string, error) {
 	newPath, err := ioutil.TempDir(path.Dir(oldPath), newName)
 	if err != nil {