type RenameDataResp struct {
	Sign       []byte `msg:"s"`
	OldDataDir string `msg:"od"` // contains '<uuid>', it is designed to be passed as value to Delete(bucket, pathJoin(object, dataDir))
}

const (
	checkPartUnknown int = iota

	// Changing the order can cause a data loss
	// when running two nodes with incompatible versions
	checkPartSuccess
	checkPartDiskNotFound
	checkPartVolumeNotFound
	checkPartFileNotFound

		return io.ErrShortWrite
	}

	return nil
}

// checkPart is a light check of an existing and size of a part, without doing a bitrot operation
// For any unexpected error, return checkPartUnknown (zero)
func (s *xlStorage) checkPart(volumeDir, path, dataDir string, partNum int, expectedSize int64, skipAccessCheck bool) (resp int) {
	partPath := pathJoin(path, dataDir, fmt.Sprintf("part.%d", partNum))