return errXLBackend
	}

	return nil
}

// A single function to write certain errors to be fatal
// or informative based on the `exit` flag, please look
// at each implementation of error for added hints.
//
// FIXME: This is an unusual function but serves its purpose for
// now, need to revisit the overall erroring structure here.
// Do not like it :-(

	if crypto.S3.IsRequested(header) && crypto.SSEC.IsRequested(header) {
		return key, crypto.ErrIncompatibleEncryptionMethod
	}

	k, err := crypto.SSEC.ParseHTTP(header)
	return k[:], err
}

// This function rotates old to new key.
func rotateKey(ctx context.Context, oldKey []byte, newKeyID string, newKey []byte, bucket, object string, metadata map[string]string, cryptoCtx kms.Context) error {
	kind, _ := crypto.IsEncrypted(metadata)

	case strings.Contains(err.Error(), "server closed idle connection"):
		return true
	}

	return false
}

// Converts network error to storageErr. This function is
// written so that the storageAPI errors are consistent
// across network disks.
func toStorageErr(err error) error {
	if err == nil {
		return nil
	}

	if isNetworkError(err) {
		return errDiskNotFound

	r.Targets = replicationStatusesMap(rstatus)
	return
}

// SetEvalMetadataFn sets the metadata evaluation function
func (o *ObjectOptions) SetEvalMetadataFn(f EvalMetadataFn) {
	o.EvalMetadataFn = f
}

// SetEvalRetentionBypassFn sets the retention bypass function
func (o *ObjectOptions) SetEvalRetentionBypassFn(f EvalRetentionBypassFn) {
	o.EvalRetentionBypassFn = f
}

// or a function call.
type PrimaryTerm struct {
	Value         *LitValue   `parser:"  @@"`
	JPathExpr     *JSONPath   `parser:"| @@"`
	ListExpr      *ListExpr   `parser:"| @@"`
	SubExpression *Expression `parser:"| \"(\" @@ \")\""`
	// Include function expressions here.
	FuncCall *FuncExpr `parser:"| @@"`
}

// FuncExpr represents a function call
type FuncExpr struct {

// admin-handler unit tests.
type adminErasureTestBed struct {
	erasureDirs []string
	objLayer    ObjectLayer
	router      *mux.Router
	done        context.CancelFunc
}

// prepareAdminErasureTestBed - helper function that setups a single-node
// Erasure backend for admin-handler tests.
func prepareAdminErasureTestBed(ctx context.Context) (*adminErasureTestBed, error) {
	ctx, cancel := context.WithCancel(ctx)

//
// Any change here should be discussed by opening an issue at
// https://github.com/minio/minio/issues.
func getUserAgent(mode string) string {
	userAgentParts := []string{}
	// Helper function to concisely append a pair of strings to a
	// the user-agent slice.
	uaAppend := func(p, q string) {
		userAgentParts = append(userAgentParts, p, q)
	}
	uaAppend(MinioUAName, " (")
	uaAppend("", runtime.GOOS)

	res := make(DailyAllTierStats, len(t.lastDayStats))
	for tier, st := range t.lastDayStats {
		res[tier] = st.clone()
	}
	return res
}

// UpdateWorkers at the end of this function leaves n goroutines waiting for
// transition tasks
func (t *transitionState) UpdateWorkers(n int) {
	t.mu.Lock()
	defer t.mu.Unlock()
	if t.objAPI == nil { // Init hasn't been called yet.
		return
	}

	return deleteBucketLocal(ctx, bucket, opts)
}

// client to talk to peer Nodes.
type remotePeerS3Client struct {
	node  Node
	pools []int

	// Function that returns the grid connection for this peer when initialized.
	// Will return nil if the grid connection is not initialized yet.
	gridConn func() *grid.Connection
}

// S3PeerSys - S3 peer call system.

		Closer:        r,
	}
}

// ObjectSegmentReaderFn is a function that returns a reader for a contiguous
// suffix segment of an object starting at the given (non-negative) offset.
type ObjectSegmentReaderFn func(offset int64) (io.ReadCloser, error)

// ObjectReadSeekCloser implements ReadSeekCloser interface for reading objects.
// It uses a function that returns a io.ReadCloser for the object.
type ObjectReadSeekCloser struct {