code: func (e *expanderDefaults) NodeExpand(rsOpt volume.NodeResizeOptions) (bool, error) {
  	klog.Warning(logPrefix(e.plugin), "using default filesystem resize for volume ", rsOpt.VolumeSpec.Name(), ", at ", rsOpt.DevicePath)
  	_, err := util.GenericResizeFS(e.plugin.host, e.plugin.GetPluginName(), rsOpt.DevicePath, rsOpt.DeviceMountPath)
  	if err != nil {
  		return false, err
  	}
  	return true, nil
  }
docs: // the defaults for NodeExpand return a generic resize indicator that will trigger the operation executor to go ahead with
  // generic filesystem resize