func (c byCapacity) Swap(i, j int) {
	c.volumes[i], c.volumes[j] = c.volumes[j], c.volumes[i]
}

func (c byCapacity) Len() int {
	return len(c.volumes)
}

// matchStorageCapacity is a matchPredicate used to sort and find volumes
func matchStorageCapacity(pvA, pvB *v1.PersistentVolume) bool {
	aQty := pvA.Spec.Capacity[v1.ResourceStorage]
	bQty := pvB.Spec.Capacity[v1.ResourceStorage]
	return aQty.Cmp(bQty) <= 0