)

// local lock servers
var globalLockServer *localLocker

// RWLocker - locker interface to introduce GetRLock, RUnlock.
type RWLocker interface {
	GetLock(ctx context.Context, timeout *dynamicTimeout) (lkCtx LockContext, timedOutErr error)
	Unlock(lkCtx LockContext)
	GetRLock(ctx context.Context, timeout *dynamicTimeout) (lkCtx LockContext, timedOutErr error)
	RUnlock(lkCtx LockContext)
}

	nsUnlocker := func() {}
	defer func() {
		if unlockOnDefer {
			nsUnlocker()
		}
	}()

	// Acquire lock
	if !opts.NoLock {
		lock := z.NewNSLock(bucket, object)
		lkctx, err := lock.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		ctx = lkctx.Context()
		nsUnlocker = func() { lock.RUnlock(lkctx) }
		unlockOnDefer = true
	}

		Timeout: drwMutexInfinite,
	})
}

// GetRLock tries to get a read lock on dm before the timeout elapses.
//
// If one or more read locks are already in use, it will grant another lock.
// Otherwise the calling go routine blocks until either the mutex becomes
// available and return success or more time has passed than the timeout
// value and return false.

	}

	dm := NewDRWMutex(ds, "aap")
	dm.refreshInterval = testDrwMutexRefreshInterval

	ctx, cancel := context.WithCancel(context.Background())

	if !dm.GetLock(ctx, cancel, id, source, Options{Timeout: 5 * time.Minute}) {
		t.Fatal("GetLock() should be successful")
	}

	// Make it run twice.
	timer := time.NewTimer(testDrwMutexRefreshInterval * 2)

	select {
	case <-ctx.Done():

	nsUnlocker := func() {}
	defer func() {
		if unlockOnDefer {
			nsUnlocker()
		}
	}()

	// Acquire lock
	if !opts.NoLock {
		lock := er.NewNSLock(bucket, object)
		lkctx, err := lock.GetRLock(ctx, globalOperationTimeout)
		if err != nil {
			return nil, err
		}
		ctx = lkctx.Context()

		// Release lock when the metadata is verified, and reader
		// is ready to be read.
		//

		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrNotImplemented), r.URL)
		return
	}

	nsLock := objectAPI.NewNSLock(minioMetaBucket, "site-net-perf")
	lkctx, err := nsLock.GetLock(ctx, globalOperationTimeout)
	if err != nil {
		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(toAPIErrorCode(ctx, err)), r.URL)
		return
	}
	ctx = lkctx.Context()
	defer nsLock.Unlock(lkctx)

	if opts.CheckPrecondFn != nil {
		if !opts.NoLock {
			ns := er.NewNSLock(bucket, object)
			lkctx, err := ns.GetLock(ctx, globalOperationTimeout)
			if err != nil {
				return nil, err
			}
			ctx = lkctx.Context()
			defer ns.Unlock(lkctx)
			opts.NoLock = true
		}

		}, idx, *client.host)
	}
	return ng.Wait()
}

var errPeerNotReachable = errors.New("peer is not reachable")

// GetLocks - makes GetLocks RPC call on all peers.
func (sys *NotificationSys) GetLocks(ctx context.Context, r *http.Request) []*PeerLocks {
	locksResp := make([]*PeerLocks, len(sys.peerClients))
	g := errgroup.WithNErrs(len(sys.peerClients))

	versionSuspended := globalBucketVersioningSys.PrefixSuspended(srcBucket, srcObject)

	lock := api.NewNSLock(r.Bucket, objInfo.Name)
	lkctx, err := lock.GetLock(ctx, globalOperationTimeout)
	if err != nil {
		return err
	}
	ctx = lkctx.Context()
	defer lock.Unlock(lkctx)

	opts := ObjectOptions{
		VersionID:        objInfo.VersionID,

		Bucket:    bucket,
		Object:    object,
		VersionID: versionID,
		DiskCount: len(storageDisks),
	}

	if !opts.NoLock {
		lk := er.NewNSLock(bucket, object)
		lkctx, err := lk.GetLock(ctx, globalOperationTimeout)
		if err != nil {
			return result, err
		}
		ctx = lkctx.Context()
		defer lk.Unlock(lkctx)
	}

	// Re-read when we have lock...