lastBlockSize := totalLength % e.blockSize
	lastShardSize := ceilFrac(lastBlockSize, int64(e.dataBlocks))
	return numShards*e.ShardSize() + lastShardSize
}

// ShardFileOffset - returns the effective offset where erasure reading begins.
func (e *Erasure) ShardFileOffset(startOffset, length, totalLength int64) int64 {
	shardSize := e.ShardSize()
	shardFileSize := e.ShardFileSize(totalLength)
	endShard := (startOffset + length) / e.blockSize

		// Get the checksums of the current part.
		bitrotReaders := make([]io.ReaderAt, len(disks))
		for index, disk := range disks {
			if disk == OfflineDisk {
				continue
			}
			tillOffset := erasure.ShardFileOffset(test.offset, test.length, test.data)

			bitrotReaders[index] = newBitrotReader(disk, nil, "testbucket", "object", tillOffset, writeAlgorithm, bitrotWriterSum(writers[index]), erasure.ShardSize())
		}

			partNumber := latestMeta.Parts[partIndex].Number
			partIdx := latestMeta.Parts[partIndex].Index
			partChecksums := latestMeta.Parts[partIndex].Checksums
			tillOffset := erasure.ShardFileOffset(0, partSize, partSize)
			readers := make([]io.ReaderAt, len(latestDisks))
			prefer := make([]bool, len(latestDisks))
			checksumAlgo := erasureInfo.GetChecksumInfo(partNumber).Algorithm

		// partLength should be adjusted so that we don't write more data than what was requested.
		if partLength > (length - totalBytesRead) {
			partLength = length - totalBytesRead
		}

		tillOffset := erasure.ShardFileOffset(partOffset, partLength, partSize)
		// Get the checksums of the current part.
		readers := make([]io.ReaderAt, len(onlineDisks))
		prefer := make([]bool, len(onlineDisks))
		for index, disk := range onlineDisks {