if err := d.calcError(); err != nil {
		return err
	}
	return d.disk.MakeVol(ctx, volume)
}

func (d *naughtyDisk) ListVols(ctx context.Context) (vols []VolInfo, err error) {
	if err := d.calcError(); err != nil {
		return nil, err
	}
	return d.disk.ListVols(ctx)
}

func (d *naughtyDisk) StatVol(ctx context.Context, volume string) (vol VolInfo, err error) {

					// This will give an estimate of the total ops/s.
					latency := float64(atomic.LoadInt64(&lat)) / float64(time.Millisecond)
					b.ReportMetric(float64(n)*float64(ops)/spent.Seconds(), "vops/s")
					b.ReportMetric(latency/float64(ops), "ms/op")
				}
			})
		}
	})
	b.Run("rpc", func(b *testing.B) {
		for par := 1; par <= 32; par *= 2 {

	return errInvalidArgument
}

// ListVols - List all volumes on a remote disk.
func (client *storageRESTClient) ListVols(ctx context.Context) (vols []VolInfo, err error) {
	return nil, errInvalidArgument
}

// StatVol - get volume info over the network.
func (client *storageRESTClient) StatVol(ctx context.Context, volume string) (vol VolInfo, err error) {

	// Volume operations.
	MakeVol(ctx context.Context, volume string) (err error)
	MakeVolBulk(ctx context.Context, volumes ...string) (err error)
	ListVols(ctx context.Context) (vols []VolInfo, err error)
	StatVol(ctx context.Context, volume string) (vol VolInfo, err error)
	DeleteVol(ctx context.Context, volume string, forceDelete bool) (err error)

	}

	var volInfos []VolInfo
	// TestXLStorage empty list vols.
	if volInfos, err = xlStorage.ListVols(context.Background()); err != nil {
		t.Fatalf("expected: <nil>, got: %s", err)
	} else if len(volInfos) != 1 {
		t.Fatalf("expected: one entry, got: %s", volInfos)
	}

	// TestXLStorage non-empty list vols.
	if err = xlStorage.MakeVol(context.Background(), "success-vol"); err != nil {