func _store(t *testing.T, vol *UnixVolume, filename string, block []byte) {
blockdir := fmt.Sprintf("%s/%s", vol.root, filename[:3])
if err := os.MkdirAll(blockdir, 0755); err != nil {
func _store(t *testing.T, vol *UnixVolume, filename string, block []byte) {
blockdir := fmt.Sprintf("%s/%s", vol.root, filename[:3])
if err := os.MkdirAll(blockdir, 0755); err != nil {