// this directory
	GetQuotaOnDir(path string) (QuotaID, error)

	// SetQuotaOnDir applies the specified quota ID to a directory.
	// Negative value for bytes means that a non-enforcing quota
	// should be applied (perhaps by setting a quota too large to
	// be hit)
	SetQuotaOnDir(path string, id QuotaID, bytes int64) error

	// QuotaIDIsInUse determines whether the quota ID is in use.

	if err != nil {
		return BadQuotaID, fmt.Errorf("unable to parse project ID from %s (%v)", match[1], err)
	}
	return QuotaID(projid), nil
}

// SetQuotaOnDir applies a quota to the specified directory under the specified mountpoint.
func (v linuxVolumeQuotaApplier) SetQuotaOnDir(path string, id QuotaID, bytes int64) error {
	if bytes < 0 || bytes > v.maxQuota {
		bytes = v.maxQuota
	}