if opts.IndexCB != nil {
		index = opts.IndexCB()
	}

	actualSize := data.ActualSize()
	if actualSize < 0 {
		_, encrypted := crypto.IsEncrypted(fi.Metadata)
		compressed := fi.IsCompressed()
		switch {
		case compressed:
			// ... nothing changes for compressed stream.
			// if actualSize is -1 we have no known way to
			// determine what is the actualSize.
		case encrypted:
			decSize, err := sio.DecryptedSize(uint64(n))

		forceMD5 = mustGetUUIDBytes()
	}

	hashReader, err := hash.NewReaderWithOpts(ctx, reader, hash.Options{
		Size:       size,
		MD5Hex:     md5hex,
		SHA256Hex:  sha256hex,
		ActualSize: actualSize,
		DisableMD5: false,
		ForceMD5:   forceMD5,
	})
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	// Set the actual size to the compressed/decrypted size if encrypted.
	actualSize, err := srcInfo.GetActualSize()
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}
	length := actualSize

	if !cpSrcDstSame {
		if err := enforceBucketQuotaHard(ctx, dstBucket, actualSize); err != nil {
			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return
		}

		modTime = UTCNow()
	}

	kind, encrypted := crypto.IsEncrypted(userDefined)
	actualSize := data.ActualSize()
	if actualSize < 0 {
		compressed := fi.IsCompressed()
		switch {
		case compressed:
			// ... nothing changes for compressed stream.
			// if actualSize is -1 we have no known way to
			// determine what is the actualSize.
		case encrypted:
			decSize, err := sio.DecryptedSize(uint64(n))

	oi := gr.ObjInfo

	defer func() {
		gr.Close()
		auditLogRebalance(ctx, "RebalanceCopyData", oi.Bucket, oi.Name, oi.VersionID, err)
	}()

	actualSize, err := oi.GetActualSize()
	if err != nil {
		return err
	}

	if oi.isMultipart() {
		res, err := z.NewMultipartUpload(ctx, bucket, oi.Name, ObjectOptions{
			VersionID:    oi.VersionID,