code: func ErrDTypeNotSupported(driver, backingFs string) error {
  	msg := fmt.Sprintf("%s: the backing %s filesystem is formatted without d_type support, which leads to incorrect behavior.", driver, backingFs)
  	if backingFs == "xfs" {
  		msg += " Reformat the filesystem with ftype=1 to enable d_type support."
  	}
  
  	if backingFs == "extfs" {
  		msg += " Reformat the filesystem (or use tune2fs) with -O filetype flag to enable d_type support."
  	}
  
  	msg += " Backing filesystems without d_type support are not supported."
  
  	return graphdriver.NotSupportedError(msg)
  }
docs: // ErrDTypeNotSupported denotes that the backing filesystem doesn't support d_type.