}
	timeout.LogSuccess(UTCNow().Sub(start))
	return LockContext{ctx: newCtx, cancel: cancel}, nil
}

// Unlock - block until write lock is released.
func (di *distLockInstance) Unlock(lc LockContext) {
	if lc.cancel != nil {
		lc.cancel()
	}
	di.rwMutex.Unlock(lc.ctx)
}

// RLock - block until read lock is taken or timeout has occurred.

	}
	return ok, err
}

// RLock calls read lock REST API.
func (c *lockRESTClient) RLock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCRLock, &args)
}

// Lock calls lock REST API.
func (c *lockRESTClient) Lock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCLock, &args)
}

// RUnlock calls read unlock REST API.

	*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()
}

	// Do read unlock for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of unlock request operation.
	// Canceling the context will abort the remote call.
	// In that case, the resource may or may not be unlocked.
	RUnlock(ctx context.Context, args LockArgs) (bool, error)

	// Do write unlock for given LockArgs. It should return

	}

	return nil, ErrInvalidDB
}

func (db *PreparedStmtDB) Close() {
	db.Mux.Lock()
	defer db.Mux.Unlock()

	for _, query := range db.PreparedSQL {
		if stmt, ok := db.Stmts[query]; ok {
			delete(db.Stmts, query)
			go stmt.Close()
		}
	}
}

func (sdb *PreparedStmtDB) Reset() {
	sdb.Mux.Lock()
	defer sdb.Mux.Unlock()

	for _, stmt := range sdb.Stmts {
		go stmt.Close()
	}

		// lk1; ref=1
		if !nsLk.lock(ctx, "volume", "path", "source", "opsID", false, time.Second) {
			t.Fatal("failed to acquire lock")
		}

		// lk2
		lk2ch := make(chan struct{})
		go func() {
			defer close(lk2ch)
			nsLk.lock(ctx, "volume", "path", "source", "opsID", false, 1*time.Millisecond)
		}()
		time.Sleep(1 * time.Millisecond) // wait for goroutine to advance; ref=2

		// Unlock the 1st lock; ref=1 after this line

	mu := NewDRWMutex(ds, "test-runlock-panic-2")
	defer func() {
		if recover() == nil {
			t.Fatalf("read unlock of unlocked RWMutex did not panic")
		}
		mu.Unlock(context.Background()) // Unlock, so -test.count > 1 works
	}()
	mu.Lock(id, source)
	mu.RUnlock(context.Background())
}

// Borrowed from rwmutex_test.go
func benchmarkRWMutex(b *testing.B, localWork, writeRatio int) {
	b.ResetTimer()

		}
	}()
	mu := NewLRWMutex()
	mu.RLock()
	mu.Unlock()
}

// Borrowed from rwmutex_test.go
func TestRUnlockPanic(t *testing.T) {
	defer func() {
		if recover() == nil {
			t.Fatalf("read unlock of unlocked RWMutex did not panic")
		}
	}()
	mu := NewLRWMutex()
	mu.RUnlock()
}

// Borrowed from rwmutex_test.go
func TestRUnlockPanic2(t *testing.T) {

	m.init.Do(m.initManager)
	m.mu.Lock()
	b, ok := m.buckets[bucket]
	if !ok {
		m.mu.Unlock()
		return
	}
	delete(m.buckets, bucket)
	m.mu.Unlock()

	// Since deletes may take some time we try to do it without
	// holding lock to m all the time.
	b.mu.Lock()
	defer b.mu.Unlock()
	for k, v := range b.caches {

			return
		}
	}
}

func (m *Monitor) updateMovingAvg() {
	m.mlock.Lock()
	defer m.mlock.Unlock()
	for _, bucketMeasurement := range m.bucketsMeasurement {
		bucketMeasurement.updateExponentialMovingAverage(time.Now())
	}
}

func (m *Monitor) init(opts BucketOptions) {
	m.mlock.Lock()
	defer m.mlock.Unlock()

	_, ok := m.bucketsMeasurement[opts]
	if !ok {