crc := expPart.Checksums[checksumType.String()]
			if crc == "" {
				return oi, InvalidPart{
					PartNumber: part.PartNumber,
				}
			}
			wantCS := map[string]string{
				hash.ChecksumCRC32.String():     part.ChecksumCRC32,
				hash.ChecksumCRC32C.String():    part.ChecksumCRC32C,
				hash.ChecksumSHA1.String():      part.ChecksumSHA1,
				hash.ChecksumSHA256.String():    part.ChecksumSHA256,

	// Metadata operations
	PutObjectMetadata(context.Context, string, string, ObjectOptions) (ObjectInfo, error)
	DecomTieredObject(context.Context, string, string, FileInfo, ObjectOptions) error

	// ObjectTagging operations
	PutObjectTags(context.Context, string, string, string, ObjectOptions) (ObjectInfo, error)
	GetObjectTags(context.Context, string, string, ObjectOptions) (*tags.Tags, error)

// header values specified in X-Amz-Metadata-Directive.
func getCpObjMetadataFromHeader(ctx context.Context, r *http.Request, userMeta map[string]string) (map[string]string, error) {
	// Make a copy of the supplied metadata to avoid
	// to change the original one.
	defaultMeta := make(map[string]string, len(userMeta))
	for k, v := range userMeta {
		// skip tier metadata when copying metadata from source object
		switch k {

	if sc := r.Header.Get(xhttp.AmzStorageClass); sc != "" {
		if !storageclass.IsValid(sc) {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidStorageClass), r.URL)
			return
		}
	}

	encMetadata := map[string]string{}

	if crypto.Requested(r.Header) {
		if crypto.SSECopy.IsRequested(r.Header) {
			writeErrorResponse(ctx, w, toAPIError(ctx, errInvalidEncryptionParameters), r.URL)
			return
		}