code: func ValidateStorageClassUpdate(storageClass, oldStorageClass *storage.StorageClass) field.ErrorList {
  	allErrs := apivalidation.ValidateObjectMetaUpdate(&storageClass.ObjectMeta, &oldStorageClass.ObjectMeta, field.NewPath("metadata"))
  	if !reflect.DeepEqual(oldStorageClass.Parameters, storageClass.Parameters) {
  		allErrs = append(allErrs, field.Forbidden(field.NewPath("parameters"), "updates to parameters are forbidden."))
  	}
  
  	if storageClass.Provisioner != oldStorageClass.Provisioner {
  		allErrs = append(allErrs, field.Forbidden(field.NewPath("provisioner"), "updates to provisioner are forbidden."))
  	}
  
  	if *storageClass.ReclaimPolicy != *oldStorageClass.ReclaimPolicy {
  		allErrs = append(allErrs, field.Forbidden(field.NewPath("reclaimPolicy"), "updates to reclaimPolicy are forbidden."))
  	}
  
  	allErrs = append(allErrs, apivalidation.ValidateImmutableField(storageClass.VolumeBindingMode, oldStorageClass.VolumeBindingMode, field.NewPath("volumeBindingMode"))...)
  	return allErrs
  }
docs: // ValidateStorageClassUpdate tests if an update to StorageClass is valid.