@@ -2115,7 +2115,7 @@ func (devices *DeviceSet) MountDevice(hash, path, mountLabel string) error {

 }

 // UnmountDevice unmounts the device and removes it from hash.

-func (devices *DeviceSet) UnmountDevice(hash string) error {

+func (devices *DeviceSet) UnmountDevice(hash, mountPath string) error {

 	logrus.Debugf("[devmapper] UnmountDevice(hash=%s)", hash)

 	defer logrus.Debugf("[devmapper] UnmountDevice(hash=%s) END", hash)

@@ -2130,17 +2130,22 @@ func (devices *DeviceSet) UnmountDevice(hash string) error {

 	devices.Lock()

 	defer devices.Unlock()

-	if info.mountCount == 0 {

-		return fmt.Errorf("UnmountDevice: device not-mounted id %s", hash)

-	}

+	// If there are running containers when daemon crashes, during daemon

+	// restarting, it will kill running contaienrs and will finally call

+	// Put() without calling Get(). So info.MountCount may become negative.

+	// if info.mountCount goes negative, we do the unmount and assign

+	// it to 0.

 	info.mountCount--

 	if info.mountCount > 0 {

 		return nil

+	} else if info.mountCount < 0 {

+		logrus.Warnf("[devmapper] Mount count of device went negative. Put() called without matching Get(). Resetting count to 0")

+		info.mountCount = 0

 	}

-	logrus.Debugf("[devmapper] Unmount(%s)", info.mountPath)

-	if err := syscall.Unmount(info.mountPath, syscall.MNT_DETACH); err != nil {

+	logrus.Debugf("[devmapper] Unmount(%s)", mountPath)

+	if err := syscall.Unmount(mountPath, syscall.MNT_DETACH); err != nil {

 		return err

 	}

 	logrus.Debugf("[devmapper] Unmount done")

@@ -186,7 +186,7 @@ func (d *Driver) Get(id, mountLabel string) (string, error) {

 	rootFs := path.Join(mp, "rootfs")

 	if err := idtools.MkdirAllAs(rootFs, 0755, uid, gid); err != nil && !os.IsExist(err) {

-		d.DeviceSet.UnmountDevice(id)

+		d.DeviceSet.UnmountDevice(id, mp)

 		return "", err

 	}

@@ -195,7 +195,7 @@ func (d *Driver) Get(id, mountLabel string) (string, error) {

 		// Create an "id" file with the container/image id in it to help reconscruct this in case

 		// of later problems

 		if err := ioutil.WriteFile(idFile, []byte(id), 0600); err != nil {

-			d.DeviceSet.UnmountDevice(id)

+			d.DeviceSet.UnmountDevice(id, mp)

 			return "", err

 		}

 	}

@@ -205,7 +205,8 @@ func (d *Driver) Get(id, mountLabel string) (string, error) {

 // Put unmounts a device and removes it.

 func (d *Driver) Put(id string) error {

-	err := d.DeviceSet.UnmountDevice(id)

+	mp := path.Join(d.home, "mnt", id)

+	err := d.DeviceSet.UnmountDevice(id, mp)

 	if err != nil {

 		logrus.Errorf("Error unmounting device %s: %s", id, err)

 	}