wait()
					return nil
				})
			})
		}(disk)
	}
	wg.Wait()
}

// nsScanner will start scanning buckets and send updated totals as they are traversed.
// Updates are sent on a regular basis and the caller *must* consume them.
func (er erasureObjects) nsScanner(ctx context.Context, buckets []BucketInfo, wantCycle uint32, updates chan<- dataUsageCache, healScanMode madmin.HealScanMode) error {

func (d *naughtyDisk) SetDiskID(id string) {
	d.disk.SetDiskID(id)
}

func (d *naughtyDisk) NSScanner(ctx context.Context, cache dataUsageCache, updates chan<- dataUsageEntry, scanMode madmin.HealScanMode, weSleep func() bool) (info dataUsageCache, err error) {
	if err := d.calcError(); err != nil {
		return info, err
	}
	return d.disk.NSScanner(ctx, cache, updates, scanMode, weSleep)
}

type ObjectLayer interface {
	// Locking operations on object.
	NewNSLock(bucket string, objects ...string) RWLocker

	// Storage operations.
	Shutdown(context.Context) error
	NSScanner(ctx context.Context, updates chan<- DataUsageInfo, wantCycle uint32, scanMode madmin.HealScanMode) error
	BackendInfo() madmin.BackendInfo

func (p *xlStorageDiskIDCheck) Hostname() string {
	return p.storage.Hostname()
}

func (p *xlStorageDiskIDCheck) Healing() *healingTracker {
	return p.storage.Healing()
}

func (p *xlStorageDiskIDCheck) NSScanner(ctx context.Context, cache dataUsageCache, updates chan<- dataUsageEntry, scanMode madmin.HealScanMode, _ func() bool) (dataUsageCache, error) {
	if contextCanceled(ctx) {
		xioutil.SafeClose(updates)

func (client *storageRESTClient) Healing() *healingTracker {
	// This call is not implemented for remote client on purpose.
	// healing tracker is always for local disks.
	return nil
}

func (client *storageRESTClient) NSScanner(ctx context.Context, cache dataUsageCache, updates chan<- dataUsageEntry, scanMode madmin.HealScanMode, _ func() bool) (dataUsageCache, error) {
	defer xioutil.SafeClose(updates)

	minSleep time.Duration

	// cycle will be closed
	cycle chan struct{}

	// isScanner should be set when this is used by the scanner
	// to record metrics.
	isScanner bool
}

// newDynamicSleeper
func newDynamicSleeper(factor float64, maxWait time.Duration, isScanner bool) *dynamicSleeper {
	return &dynamicSleeper{
		factor:    factor,
		cycle:     make(chan struct{}),

	wg.Add(1)
	go func() {
		defer wg.Done()
		for update := range updates {
			resp := storageNSScannerRPC.NewResponse()
			resp.Update = &update
			out <- resp
		}
	}()
	ui, err := s.getStorage().NSScanner(ctx, *params.Cache, updates, madmin.HealScanMode(params.ScanMode), nil)
	wg.Wait()
	if err != nil {
		return grid.NewRemoteErr(err)
	}
	// Send final response.
	resp := storageNSScannerRPC.NewResponse()

	scanner.Split(ScanWords)
	if !scanner.Scan() {
		t.Fatalf("scan failed: %v", scanner.Err())
	}
	if token := scanner.Text(); token != word {
		t.Fatalf("unexpected token: %v", token)
	}
}

// Test that empty tokens, including at end of line or end of file, are found by the scanner.
// Issue 8672: Could miss final empty token.

usage calculation. The scanner adapts to the system speed and completely pauses when the system is under load. It is possible to adjust the speed of the scanner and thereby the latency of updates being reflected. The delays between each operation of the scanner can be adjusted by the `mc admin config set alias/ delay=15.0`. By default the value is `10.0`. This means the scanner will sleep *10x* the time each operation takes.

In most setups this will keep the scanner slow enough to not impact...

		return
	}

	// Constant.
	haveConstant := false
	switch tok.ScanToken {
	case scanner.Int, scanner.Float, scanner.String, scanner.Char, '+', '-', '~':
		haveConstant = true
	case '(':
		// Could be parenthesized expression or (R). Must be something, though.
		tok := p.next()
		if tok.ScanToken == scanner.EOF {
			p.errorf("missing right parenthesis")
			return
		}
		rname := tok.String()
		p.back()