@@ -771,10 +771,15 @@ func (devices *DeviceSet) deactivatePool() error {

 	log.Debugf("[devmapper] deactivatePool()")

 	defer log.Debugf("[devmapper] deactivatePool END")

 	devname := devices.getPoolDevName()

+

 	devinfo, err := getInfo(devname)

 	if err != nil {

 		return err

 	}

+	if d, err := getDeps(devname); err == nil {

+		// Access to more Debug output

+		log.Debugf("[devmapper] getDeps() %s: %#v", devname, d)

+	}

 	if devinfo.Exists != 0 {

 		return removeDevice(devname)

 	}

@@ -51,6 +51,7 @@ var (

 	ErrTaskSetRo              = errors.New("dm_task_set_ro failed")

 	ErrTaskAddTarget          = errors.New("dm_task_add_target failed")

 	ErrTaskSetSector          = errors.New("dm_task_set_sector failed")

+	ErrTaskGetDeps            = errors.New("dm_task_get_deps failed")

 	ErrTaskGetInfo            = errors.New("dm_task_get_info failed")

 	ErrTaskGetDriverVersion   = errors.New("dm_task_get_driver_version failed")

 	ErrTaskSetCookie          = errors.New("dm_task_set_cookie failed")

@@ -75,6 +76,11 @@ type (

 	Task struct {

 		unmanaged *CDmTask

 	}

+	Deps struct {

+		Count  uint32

+		Filler uint32

+		Device []uint64

+	}

 	Info struct {

 		Exists        int

 		Suspended     int

@@ -171,6 +177,14 @@ func (t *Task) AddTarget(start, size uint64, ttype, params string) error {

 	return nil

 }

+func (t *Task) GetDeps() (*Deps, error) {

+	var deps *Deps

+	if deps = DmTaskGetDeps(t.unmanaged); deps == nil {

+		return nil, ErrTaskGetDeps

+	}

+	return deps, nil

+}

+

 func (t *Task) GetInfo() (*Info, error) {

 	info := &Info{}

 	if res := DmTaskGetInfo(t.unmanaged, info); res != 1 {

@@ -392,6 +406,17 @@ func createTask(t TaskType, name string) (*Task, error) {

 	return task, nil

 }

+func getDeps(name string) (*Deps, error) {

+	task, err := createTask(DeviceDeps, name)

+	if task == nil {

+		return nil, err

+	}

+	if err := task.Run(); err != nil {

+		return nil, err

+	}

+	return task.GetDeps()

+}

+

 func getInfo(name string) (*Info, error) {

 	task, err := createTask(DeviceInfo, name)

 	if task == nil {

@@ -3,8 +3,9 @@

 package devmapper

 import (

-	"github.com/docker/docker/daemon/graphdriver/graphtest"

 	"testing"

+

+	"github.com/docker/docker/daemon/graphdriver/graphtest"

 )

 func init() {

@@ -38,9 +38,7 @@ static void	log_with_errno_init()

 */

 import "C"

-import (

-	"unsafe"

-)

+import "unsafe"

 type (

 	CDmTask C.struct_dm_task

@@ -92,6 +90,7 @@ var (

 	DmTaskAddTarget        = dmTaskAddTargetFct

 	DmTaskCreate           = dmTaskCreateFct

 	DmTaskDestroy          = dmTaskDestroyFct

+	DmTaskGetDeps          = dmTaskGetDepsFct

 	DmTaskGetInfo          = dmTaskGetInfoFct

 	DmTaskGetDriverVersion = dmTaskGetDriverVersionFct

 	DmTaskRun              = dmTaskRunFct

@@ -168,6 +167,21 @@ func dmTaskAddTargetFct(task *CDmTask,

 	return int(C.dm_task_add_target((*C.struct_dm_task)(task), C.uint64_t(start), C.uint64_t(size), Cttype, Cparams))

 }

+func dmTaskGetDepsFct(task *CDmTask) *Deps {

+	Cdeps := C.dm_task_get_deps((*C.struct_dm_task)(task))

+	if Cdeps == nil {

+		return nil

+	}

+	deps := &Deps{

+		Count:  uint32(Cdeps.count),

+		Filler: uint32(Cdeps.filler),

+	}

+	for _, device := range Cdeps.device {

+		deps.Device = append(deps.Device, (uint64)(device))

+	}

+	return deps

+}

+

 func dmTaskGetInfoFct(task *CDmTask, info *Info) int {

 	Cinfo := C.struct_dm_info{}

 	defer func() {