func TestBtrfsSubvolDelete(t *testing.T) {
	d := graphtest.GetDriver(t, "btrfs")
	if err := d.Create("test", "", "", nil); err != nil {
		t.Fatal(err)
	}
	defer graphtest.PutDriver(t)

	dir, err := d.Get("test", "")
	if err != nil {
		t.Fatal(err)
	}
	defer d.Put("test")

	if err := subvolCreate(dir, "subvoltest"); err != nil {
		t.Fatal(err)
	}

	if _, err := os.Stat(path.Join(dir, "subvoltest")); err != nil {
		t.Fatal(err)
	}

	if err := d.Remove("test"); err != nil {
		t.Fatal(err)
	}

	if _, err := os.Stat(path.Join(dir, "subvoltest")); !os.IsNotExist(err) {
		t.Fatalf("expected not exist error on nested subvol, got: %v", err)
	}
}

// Make sure devices.Lock() has been release upon return from cleanupDeletedDevices() function
func TestDevmapperLockReleasedDeviceDeletion(t *testing.T) {
	driver := graphtest.GetDriver(t, "devicemapper").(*graphtest.Driver).Driver.(*graphdriver.NaiveDiffDriver).ProtoDriver.(*Driver)
	defer graphtest.PutDriver(t)

	// Call cleanupDeletedDevices() and after the call take and release
	// DeviceSet Lock. If lock has not been released, this will hang.
	driver.DeviceSet.cleanupDeletedDevices()

	doneChan := make(chan bool)

	go func() {
		driver.DeviceSet.Lock()
		defer driver.DeviceSet.Unlock()
		doneChan <- true
	}()

	select {
	case <-time.After(time.Second * 5):
		// Timer expired. That means lock was not released upon
		// function return and we are deadlocked. Release lock
		// here so that cleanup could succeed and fail the test.
		driver.DeviceSet.Unlock()
		t.Fatalf("Could not acquire devices lock after call to cleanupDeletedDevices()")
	case <-doneChan:
	}
}

func testChangeLoopBackSize(t *testing.T, delta, expectDataSize, expectMetaDataSize int64) {
	driver := graphtest.GetDriver(t, "devicemapper").(*graphtest.Driver).Driver.(*graphdriver.NaiveDiffDriver).ProtoDriver.(*Driver)
	defer graphtest.PutDriver(t)
	// make sure data or metadata loopback size are the default size
	if s := driver.DeviceSet.Status(); s.Data.Total != uint64(defaultDataLoopbackSize) || s.Metadata.Total != uint64(defaultMetaDataLoopbackSize) {
		t.Fatalf("data or metadata loop back size is incorrect")
	}
	if err := driver.Cleanup(); err != nil {
		t.Fatal(err)
	}
	//Reload
	d, err := Init(driver.home, []string{
		fmt.Sprintf("dm.loopdatasize=%d", defaultDataLoopbackSize+delta),
		fmt.Sprintf("dm.loopmetadatasize=%d", defaultMetaDataLoopbackSize+delta),
	}, nil, nil)
	if err != nil {
		t.Fatalf("error creating devicemapper driver: %v", err)
	}
	driver = d.(*graphdriver.NaiveDiffDriver).ProtoDriver.(*Driver)
	if s := driver.DeviceSet.Status(); s.Data.Total != uint64(expectDataSize) || s.Metadata.Total != uint64(expectMetaDataSize) {
		t.Fatalf("data or metadata loop back size is incorrect")
	}
	if err := driver.Cleanup(); err != nil {
		t.Fatal(err)
	}
}

// This avoids creating a new driver for each test if all tests are run
// Make sure to put new tests between TestDevmapperSetup and TestDevmapperTeardown
func TestDevmapperSetup(t *testing.T) {
	graphtest.GetDriver(t, "devicemapper")
}

// This avoids creating a new driver for each test if all tests are run
// Make sure to put new tests between TestVfsSetup and TestVfsTeardown
func TestVfsSetup(t *testing.T) {
	graphtest.GetDriver(t, "vfs")
}

// This avoids creating a new driver for each test if all tests are run
// Make sure to put new tests between TestRbdSetup and TestRbdTeardown
func TestRbdSetup(t *testing.T) {
	graphtest.GetDriver(t, "rbd")
}

// This avoids creating a new driver for each test if all tests are run
// Make sure to put new tests between TestOverlaySetup and TestOverlayTeardown
func TestOverlaySetup(t *testing.T) {
	graphtest.GetDriver(t, "overlay")
}

// This avoids creating a new driver for each test if all tests are run
// Make sure to put new tests between TestOverlaySetup and TestOverlayTeardown
func TestOverlaySetup(t *testing.T) {
	graphtest.GetDriver(t, driverName)
}

// This avoids creating a new driver for each test if all tests are run
// Make sure to put new tests between TestBtrfsSetup and TestBtrfsTeardown
func TestBtrfsSetup(t *testing.T) {
	graphtest.GetDriver(t, "btrfs")
}