badDisks, badStaleDisks int

	blocksize, size int64
	algorithm       BitrotAlgorithm
	shouldFail      bool
}{
	{dataBlocks: 2, disks: 4, offDisks: 1, badDisks: 0, badStaleDisks: 0, blocksize: int64(blockSizeV2), size: oneMiByte, algorithm: SHA256, shouldFail: false},                   // 0

type erasureTestSetup struct {
	dataBlocks   int
	parityBlocks int
	blockSize    int64
	diskPaths    []string
	disks        []StorageAPI
}

// Returns an initialized setup for erasure tests.
func newErasureTestSetup(tb testing.TB, dataBlocks int, parityBlocks int, blockSize int64) (*erasureTestSetup, error) {
	diskPaths := make([]string, dataBlocks+parityBlocks)

	configLock.RLock()
	defer configLock.RUnlock()

	return c.Enable && c.BlockSize > 0 && size <= c.BlockSize
}

// Update updates new cache frequency
func (c *Config) Update(ncfg Config) {
	configLock.Lock()
	defer configLock.Unlock()

	c.Enable = ncfg.Enable
	c.Endpoint = ncfg.Endpoint
	c.BlockSize = ncfg.BlockSize
	c.clnt = ncfg.clnt
}

// cache related errors
var (

// refer https://github.com/golang/go/issues/24015
const blockSize = 8 << 10 // 8192

// By default at least 128 entries in single getdents call (1MiB buffer)
var (
	direntPool = sync.Pool{
		New: func() interface{} {
			buf := make([]byte, blockSize*128)
			return &buf
		},
	}

	direntNamePool = sync.Pool{
		New: func() interface{} {
			buf := make([]byte, blockSize)
			return &buf
		},
	}
)

	}
	flag &= ^(syscall.O_DIRECT)
	_, err = unix.FcntlInt(fd, unix.F_SETFL, flag)
	return err
}

// AlignedBlock - pass through to directio implementation.
func AlignedBlock(blockSize int) []byte {
	return directio.AlignedBlock(blockSize)

func (u UUIDHash) Reset() {
	return
}

// Size -  implement hash.Hash Size
func (u UUIDHash) Size() int {
	return len(u.uuid)
}

// BlockSize -  implement hash.Hash BlockSize
func (u UUIDHash) BlockSize() int {
	return md5.BlockSize
}

var _ hash.Hash = &UUIDHash{}

// NewUUIDHash - new UUIDHash
func NewUUIDHash(uuid []byte) *UUIDHash {
	return &UUIDHash{uuid: uuid}

	DataBlocks int `json:"data"`
	// ParityBlocks is the number of parity blocks for erasure-coding
	ParityBlocks int `json:"parity"`
	// BlockSize is the size of one erasure-coded block
	BlockSize int64 `json:"blockSize"`
	// Index is the index of the current disk
	Index int `json:"index"`
	// Distribution is the distribution of the data and parity blocks
	Distribution []int `json:"distribution"`

		}
		var (
			hash = algorithm.New()
			msg  = make([]byte, 0, hash.Size()*hash.BlockSize())
			sum  = make([]byte, 0, hash.Size())
		)
		for i := 0; i < hash.Size()*hash.BlockSize(); i += hash.Size() {
			hash.Write(msg)
			sum = hash.Sum(sum[:0])
			msg = append(msg, sum...)
			hash.Reset()
		}
		if !bytes.Equal(sum, checksum) {

	fd := f.Fd()
	_, err := unix.FcntlInt(fd, unix.F_NOCACHE, 0)
	return err
}

// AlignedBlock - pass through to directio implementation.
func AlignedBlock(blockSize int) []byte {
	return directio.AlignedBlock(blockSize)

	var buf bytes.Buffer
	msgp.Encode(&buf, &v)
	rd := msgp.NewEndlessReader(buf.Bytes(), b)