*LockedFile
	mutex sync.Mutex
	refs  int // Holds read lock refs.
}

// IsClosed - Check if the rlocked file is already closed.
func (r *RLockedFile) IsClosed() bool {
	r.mutex.Lock()
	defer r.mutex.Unlock()
	return r.refs == 0
}

// IncLockRef - is used by called to indicate lock refs.
func (r *RLockedFile) IncLockRef() {
	r.mutex.Lock()
	r.refs++
	r.mutex.Unlock()
}

	// Attempt all calls.
	_, err = lkClient.RLock(context.Background(), dsync.LockArgs{})
	if err == nil {
		t.Fatal("Expected for Rlock to fail")
	}

	_, err = lkClient.Lock(context.Background(), dsync.LockArgs{})
	if err == nil {
		t.Fatal("Expected for Lock to fail")
	}

	_, err = lkClient.RUnlock(context.Background(), dsync.LockArgs{})
	if err == nil {
		t.Fatal("Expected for RUnlock to fail")
	}

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/** Forwarding wrapper around a {@code Lock}. */
@J2ktIncompatible
@ElementTypesAreNonnullByDefault
abstract class ForwardingLock implements Lock {
  abstract Lock delegate();

  @Override
  public void lock() {
    delegate().lock();
  }

  @Override
  public void lockInterruptibly() throws InterruptedException {

	if responses == nil {
		return nil, errors.New("RequestStream: responses channel is nil")
	}
	m.init = true
	m.respMu.Lock()
	if m.closed {
		m.respMu.Unlock()
		return nil, ErrDisconnected
	}
	m.respWait = responses // Route directly to output.
	m.respMu.Unlock()

	// Try to grab an initial block.
	m.singleResp = false
	m.RecvSeq = m.SendSeq // Sync
	if cap(requests) > 0 {

	sys.aMutex.Lock()
	defer sys.aMutex.Unlock()
	if v, ok := sys.arnErrsMap[arn]; !ok {
		sys.arnErrsMap[arn] = arnErrs{
			updateInProgress: true,
			count:            v.count + 1,
			bucket:           bucket,
		}
	}
}

func (sys *BucketTargetSys) markRefreshDone(bucket, arn string) {
	sys.aMutex.Lock()
	defer sys.aMutex.Unlock()
	if v, ok := sys.arnErrsMap[arn]; ok {

	if stats == nil {
		return
	}
	stats.Lock()
	defer stats.Unlock()
	if stats.apiStats == nil {
		stats.apiStats = make(map[string]int)
	}
	stats.apiStats[api]++
}

// Dec increments the api stats counter.
func (stats *HTTPAPIStats) Dec(api string) {
	if stats == nil {
		return
	}
	stats.Lock()
	defer stats.Unlock()
	if val, ok := stats.apiStats[api]; ok && val > 0 {

func (ahs *allHealState) setDiskHealingStatus(ep Endpoint, healing bool) {
	ahs.Lock()
	defer ahs.Unlock()

	ahs.healLocalDisks[ep] = healing
}

func (ahs *allHealState) pushHealLocalDisks(healLocalDisks ...Endpoint) {
	ahs.Lock()
	defer ahs.Unlock()

	for _, ep := range healLocalDisks {
		ahs.healLocalDisks[ep] = false
	}
}

func (ahs *allHealState) periodicHealSeqsClean(ctx context.Context) {

}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++
	t.requestsCount[tier] = stat
}

func (t *tierMetrics) logFailure(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.failure++
	t.requestsCount[tier] = stat
}

var (

type IAMStorageAPI interface {
	// The role of the read-write lock is to prevent go routines from
	// concurrently reading and writing the IAM storage. The (r)lock()
	// functions return the iamCache. The cache can be safely written to
	// only when returned by `lock()`.
	lock() *iamCache
	unlock()
	rlock() *iamCache
	runlock()
	getUsersSysType() UsersSysType

	h.mu.RLock()
	defer h.mu.RUnlock()

	return h.Object
}

func (h *healingTracker) setObject(object string) {
	h.mu.Lock()
	defer h.mu.Unlock()

	h.Object = object
}

func (h *healingTracker) updateProgress(success, skipped bool, bytes uint64) {
	h.mu.Lock()
	defer h.mu.Unlock()

	switch {
	case success:
		h.ItemsHealed++
		h.BytesDone += bytes
	case skipped:
		h.ItemsSkipped++