Build and install from GOPATH

* Rename 'vendor/src' -> 'vendor' * Ignore vendor/ instead of vendor/src/ for lint * Rename 'cmd/client' -> 'cmd/ocic' to make it 'go install'able * Rename 'cmd/server' -> 'cmd/ocid' to make it 'go install'able * Update Makefile to build and install from GOPATH * Update tests to locate ocid/ocic in GOPATH/bin * Search for binaries in GOPATH/bin instead of PATH * Install tools using `go get -u`, so they are updated on each run Signed-off-by: Jonathan Yu <jawnsy@redhat.com>
2017-01-17 11:57:35 -08:00 · 2017-01-17 11:57:35 -08:00 · 6c9628cdb1
commit 6c9628cdb1
parent 9da2882d49
1111 changed files with 70 additions and 61 deletions
--- a/vendor/github.com/containers/storage/pkg/devicemapper/devmapper.go
+++ b/vendor/github.com/containers/storage/pkg/devicemapper/devmapper.go
@ -0,0 +1,807 @@
+// +build linux
+
+package devicemapper
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"runtime"
+	"syscall"
+	"unsafe"
+
+	"github.com/Sirupsen/logrus"
+)
+
+// DevmapperLogger defines methods for logging with devicemapper.
+type DevmapperLogger interface {
+	DMLog(level int, file string, line int, dmError int, message string)
+}
+
+const (
+	deviceCreate TaskType = iota
+	deviceReload
+	deviceRemove
+	deviceRemoveAll
+	deviceSuspend
+	deviceResume
+	deviceInfo
+	deviceDeps
+	deviceRename
+	deviceVersion
+	deviceStatus
+	deviceTable
+	deviceWaitevent
+	deviceList
+	deviceClear
+	deviceMknodes
+	deviceListVersions
+	deviceTargetMsg
+	deviceSetGeometry
+)
+
+const (
+	addNodeOnResume AddNodeType = iota
+	addNodeOnCreate
+)
+
+// List of errors returned when using devicemapper.
+var (
+	ErrTaskRun              = errors.New("dm_task_run failed")
+	ErrTaskSetName          = errors.New("dm_task_set_name failed")
+	ErrTaskSetMessage       = errors.New("dm_task_set_message failed")
+	ErrTaskSetAddNode       = errors.New("dm_task_set_add_node failed")
+	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")
+	ErrTaskDeferredRemove   = errors.New("dm_task_deferred_remove failed")
+	ErrTaskSetCookie        = errors.New("dm_task_set_cookie failed")
+	ErrNilCookie            = errors.New("cookie ptr can't be nil")
+	ErrGetBlockSize         = errors.New("Can't get block size")
+	ErrUdevWait             = errors.New("wait on udev cookie failed")
+	ErrSetDevDir            = errors.New("dm_set_dev_dir failed")
+	ErrGetLibraryVersion    = errors.New("dm_get_library_version failed")
+	ErrCreateRemoveTask     = errors.New("Can't create task of type deviceRemove")
+	ErrRunRemoveDevice      = errors.New("running RemoveDevice failed")
+	ErrInvalidAddNode       = errors.New("Invalid AddNode type")
+	ErrBusy                 = errors.New("Device is Busy")
+	ErrDeviceIDExists       = errors.New("Device Id Exists")
+	ErrEnxio                = errors.New("No such device or address")
+)
+
+var (
+	dmSawBusy  bool
+	dmSawExist bool
+	dmSawEnxio bool // No Such Device or Address
+)
+
+type (
+	// Task represents a devicemapper task (like lvcreate, etc.) ; a task is needed for each ioctl
+	// command to execute.
+	Task struct {
+		unmanaged *cdmTask
+	}
+	// Deps represents dependents (layer) of a device.
+	Deps struct {
+		Count  uint32
+		Filler uint32
+		Device []uint64
+	}
+	// Info represents information about a device.
+	Info struct {
+		Exists         int
+		Suspended      int
+		LiveTable      int
+		InactiveTable  int
+		OpenCount      int32
+		EventNr        uint32
+		Major          uint32
+		Minor          uint32
+		ReadOnly       int
+		TargetCount    int32
+		DeferredRemove int
+	}
+	// TaskType represents a type of task
+	TaskType int
+	// AddNodeType represents a type of node to be added
+	AddNodeType int
+)
+
+// DeviceIDExists returns whether error conveys the information about device Id already
+// exist or not. This will be true if device creation or snap creation
+// operation fails if device or snap device already exists in pool.
+// Current implementation is little crude as it scans the error string
+// for exact pattern match. Replacing it with more robust implementation
+// is desirable.
+func DeviceIDExists(err error) bool {
+	return fmt.Sprint(err) == fmt.Sprint(ErrDeviceIDExists)
+}
+
+func (t *Task) destroy() {
+	if t != nil {
+		DmTaskDestroy(t.unmanaged)
+		runtime.SetFinalizer(t, nil)
+	}
+}
+
+// TaskCreateNamed is a convenience function for TaskCreate when a name
+// will be set on the task as well
+func TaskCreateNamed(t TaskType, name string) (*Task, error) {
+	task := TaskCreate(t)
+	if task == nil {
+		return nil, fmt.Errorf("devicemapper: Can't create task of type %d", int(t))
+	}
+	if err := task.setName(name); err != nil {
+		return nil, fmt.Errorf("devicemapper: Can't set task name %s", name)
+	}
+	return task, nil
+}
+
+// TaskCreate initializes a devicemapper task of tasktype
+func TaskCreate(tasktype TaskType) *Task {
+	Ctask := DmTaskCreate(int(tasktype))
+	if Ctask == nil {
+		return nil
+	}
+	task := &Task{unmanaged: Ctask}
+	runtime.SetFinalizer(task, (*Task).destroy)
+	return task
+}
+
+func (t *Task) run() error {
+	if res := DmTaskRun(t.unmanaged); res != 1 {
+		return ErrTaskRun
+	}
+	return nil
+}
+
+func (t *Task) setName(name string) error {
+	if res := DmTaskSetName(t.unmanaged, name); res != 1 {
+		return ErrTaskSetName
+	}
+	return nil
+}
+
+func (t *Task) setMessage(message string) error {
+	if res := DmTaskSetMessage(t.unmanaged, message); res != 1 {
+		return ErrTaskSetMessage
+	}
+	return nil
+}
+
+func (t *Task) setSector(sector uint64) error {
+	if res := DmTaskSetSector(t.unmanaged, sector); res != 1 {
+		return ErrTaskSetSector
+	}
+	return nil
+}
+
+func (t *Task) setCookie(cookie *uint, flags uint16) error {
+	if cookie == nil {
+		return ErrNilCookie
+	}
+	if res := DmTaskSetCookie(t.unmanaged, cookie, flags); res != 1 {
+		return ErrTaskSetCookie
+	}
+	return nil
+}
+
+func (t *Task) setAddNode(addNode AddNodeType) error {
+	if addNode != addNodeOnResume && addNode != addNodeOnCreate {
+		return ErrInvalidAddNode
+	}
+	if res := DmTaskSetAddNode(t.unmanaged, addNode); res != 1 {
+		return ErrTaskSetAddNode
+	}
+	return nil
+}
+
+func (t *Task) setRo() error {
+	if res := DmTaskSetRo(t.unmanaged); res != 1 {
+		return ErrTaskSetRo
+	}
+	return nil
+}
+
+func (t *Task) addTarget(start, size uint64, ttype, params string) error {
+	if res := DmTaskAddTarget(t.unmanaged, start, size,
+		ttype, params); res != 1 {
+		return ErrTaskAddTarget
+	}
+	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 {
+		return nil, ErrTaskGetInfo
+	}
+	return info, nil
+}
+
+func (t *Task) getInfoWithDeferred() (*Info, error) {
+	info := &Info{}
+	if res := DmTaskGetInfoWithDeferred(t.unmanaged, info); res != 1 {
+		return nil, ErrTaskGetInfo
+	}
+	return info, nil
+}
+
+func (t *Task) getDriverVersion() (string, error) {
+	res := DmTaskGetDriverVersion(t.unmanaged)
+	if res == "" {
+		return "", ErrTaskGetDriverVersion
+	}
+	return res, nil
+}
+
+func (t *Task) getNextTarget(next unsafe.Pointer) (nextPtr unsafe.Pointer, start uint64,
+	length uint64, targetType string, params string) {
+
+	return DmGetNextTarget(t.unmanaged, next, &start, &length,
+			&targetType, &params),
+		start, length, targetType, params
+}
+
+// UdevWait waits for any processes that are waiting for udev to complete the specified cookie.
+func UdevWait(cookie *uint) error {
+	if res := DmUdevWait(*cookie); res != 1 {
+		logrus.Debugf("devicemapper: Failed to wait on udev cookie %d", *cookie)
+		return ErrUdevWait
+	}
+	return nil
+}
+
+// LogInitVerbose is an interface to initialize the verbose logger for the device mapper library.
+func LogInitVerbose(level int) {
+	DmLogInitVerbose(level)
+}
+
+var dmLogger DevmapperLogger
+
+// LogInit initializes the logger for the device mapper library.
+func LogInit(logger DevmapperLogger) {
+	dmLogger = logger
+	LogWithErrnoInit()
+}
+
+// SetDevDir sets the dev folder for the device mapper library (usually /dev).
+func SetDevDir(dir string) error {
+	if res := DmSetDevDir(dir); res != 1 {
+		logrus.Debug("devicemapper: Error dm_set_dev_dir")
+		return ErrSetDevDir
+	}
+	return nil
+}
+
+// GetLibraryVersion returns the device mapper library version.
+func GetLibraryVersion() (string, error) {
+	var version string
+	if res := DmGetLibraryVersion(&version); res != 1 {
+		return "", ErrGetLibraryVersion
+	}
+	return version, nil
+}
+
+// UdevSyncSupported returns whether device-mapper is able to sync with udev
+//
+// This is essential otherwise race conditions can arise where both udev and
+// device-mapper attempt to create and destroy devices.
+func UdevSyncSupported() bool {
+	return DmUdevGetSyncSupport() != 0
+}
+
+// UdevSetSyncSupport allows setting whether the udev sync should be enabled.
+// The return bool indicates the state of whether the sync is enabled.
+func UdevSetSyncSupport(enable bool) bool {
+	if enable {
+		DmUdevSetSyncSupport(1)
+	} else {
+		DmUdevSetSyncSupport(0)
+	}
+
+	return UdevSyncSupported()
+}
+
+// CookieSupported returns whether the version of device-mapper supports the
+// use of cookie's in the tasks.
+// This is largely a lower level call that other functions use.
+func CookieSupported() bool {
+	return DmCookieSupported() != 0
+}
+
+// RemoveDevice is a useful helper for cleaning up a device.
+func RemoveDevice(name string) error {
+	task, err := TaskCreateNamed(deviceRemove, name)
+	if task == nil {
+		return err
+	}
+
+	var cookie uint
+	if err := task.setCookie(&cookie, 0); err != nil {
+		return fmt.Errorf("devicemapper: Can not set cookie: %s", err)
+	}
+	defer UdevWait(&cookie)
+
+	dmSawBusy = false // reset before the task is run
+	if err = task.run(); err != nil {
+		if dmSawBusy {
+			return ErrBusy
+		}
+		return fmt.Errorf("devicemapper: Error running RemoveDevice %s", err)
+	}
+
+	return nil
+}
+
+// RemoveDeviceDeferred is a useful helper for cleaning up a device, but deferred.
+func RemoveDeviceDeferred(name string) error {
+	logrus.Debugf("devicemapper: RemoveDeviceDeferred START(%s)", name)
+	defer logrus.Debugf("devicemapper: RemoveDeviceDeferred END(%s)", name)
+	task, err := TaskCreateNamed(deviceRemove, name)
+	if task == nil {
+		return err
+	}
+
+	if err := DmTaskDeferredRemove(task.unmanaged); err != 1 {
+		return ErrTaskDeferredRemove
+	}
+
+	if err = task.run(); err != nil {
+		return fmt.Errorf("devicemapper: Error running RemoveDeviceDeferred %s", err)
+	}
+
+	return nil
+}
+
+// CancelDeferredRemove cancels a deferred remove for a device.
+func CancelDeferredRemove(deviceName string) error {
+	task, err := TaskCreateNamed(deviceTargetMsg, deviceName)
+	if task == nil {
+		return err
+	}
+
+	if err := task.setSector(0); err != nil {
+		return fmt.Errorf("devicemapper: Can't set sector %s", err)
+	}
+
+	if err := task.setMessage(fmt.Sprintf("@cancel_deferred_remove")); err != nil {
+		return fmt.Errorf("devicemapper: Can't set message %s", err)
+	}
+
+	dmSawBusy = false
+	dmSawEnxio = false
+	if err := task.run(); err != nil {
+		// A device might be being deleted already
+		if dmSawBusy {
+			return ErrBusy
+		} else if dmSawEnxio {
+			return ErrEnxio
+		}
+		return fmt.Errorf("devicemapper: Error running CancelDeferredRemove %s", err)
+
+	}
+	return nil
+}
+
+// GetBlockDeviceSize returns the size of a block device identified by the specified file.
+func GetBlockDeviceSize(file *os.File) (uint64, error) {
+	size, err := ioctlBlkGetSize64(file.Fd())
+	if err != nil {
+		logrus.Errorf("devicemapper: Error getblockdevicesize: %s", err)
+		return 0, ErrGetBlockSize
+	}
+	return uint64(size), nil
+}
+
+// BlockDeviceDiscard runs discard for the given path.
+// This is used as a workaround for the kernel not discarding block so
+// on the thin pool when we remove a thinp device, so we do it
+// manually
+func BlockDeviceDiscard(path string) error {
+	file, err := os.OpenFile(path, os.O_RDWR, 0)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	size, err := GetBlockDeviceSize(file)
+	if err != nil {
+		return err
+	}
+
+	if err := ioctlBlkDiscard(file.Fd(), 0, size); err != nil {
+		return err
+	}
+
+	// Without this sometimes the remove of the device that happens after
+	// discard fails with EBUSY.
+	syscall.Sync()
+
+	return nil
+}
+
+// CreatePool is the programmatic example of "dmsetup create".
+// It creates a device with the specified poolName, data and metadata file and block size.
+func CreatePool(poolName string, dataFile, metadataFile *os.File, poolBlockSize uint32) error {
+	task, err := TaskCreateNamed(deviceCreate, poolName)
+	if task == nil {
+		return err
+	}
+
+	size, err := GetBlockDeviceSize(dataFile)
+	if err != nil {
+		return fmt.Errorf("devicemapper: Can't get data size %s", err)
+	}
+
+	params := fmt.Sprintf("%s %s %d 32768 1 skip_block_zeroing", metadataFile.Name(), dataFile.Name(), poolBlockSize)
+	if err := task.addTarget(0, size/512, "thin-pool", params); err != nil {
+		return fmt.Errorf("devicemapper: Can't add target %s", err)
+	}
+
+	var cookie uint
+	var flags uint16
+	flags = DmUdevDisableSubsystemRulesFlag | DmUdevDisableDiskRulesFlag | DmUdevDisableOtherRulesFlag
+	if err := task.setCookie(&cookie, flags); err != nil {
+		return fmt.Errorf("devicemapper: Can't set cookie %s", err)
+	}
+	defer UdevWait(&cookie)
+
+	if err := task.run(); err != nil {
+		return fmt.Errorf("devicemapper: Error running deviceCreate (CreatePool) %s", err)
+	}
+
+	return nil
+}
+
+// ReloadPool is the programmatic example of "dmsetup reload".
+// It reloads the table with the specified poolName, data and metadata file and block size.
+func ReloadPool(poolName string, dataFile, metadataFile *os.File, poolBlockSize uint32) error {
+	task, err := TaskCreateNamed(deviceReload, poolName)
+	if task == nil {
+		return err
+	}
+
+	size, err := GetBlockDeviceSize(dataFile)
+	if err != nil {
+		return fmt.Errorf("devicemapper: Can't get data size %s", err)
+	}
+
+	params := fmt.Sprintf("%s %s %d 32768 1 skip_block_zeroing", metadataFile.Name(), dataFile.Name(), poolBlockSize)
+	if err := task.addTarget(0, size/512, "thin-pool", params); err != nil {
+		return fmt.Errorf("devicemapper: Can't add target %s", err)
+	}
+
+	if err := task.run(); err != nil {
+		return fmt.Errorf("devicemapper: Error running deviceCreate %s", err)
+	}
+
+	return nil
+}
+
+// GetDeps is the programmatic example of "dmsetup deps".
+// It outputs a list of devices referenced by the live table for the specified device.
+func GetDeps(name string) (*Deps, error) {
+	task, err := TaskCreateNamed(deviceDeps, name)
+	if task == nil {
+		return nil, err
+	}
+	if err := task.run(); err != nil {
+		return nil, err
+	}
+	return task.getDeps()
+}
+
+// GetInfo is the programmatic example of "dmsetup info".
+// It outputs some brief information about the device.
+func GetInfo(name string) (*Info, error) {
+	task, err := TaskCreateNamed(deviceInfo, name)
+	if task == nil {
+		return nil, err
+	}
+	if err := task.run(); err != nil {
+		return nil, err
+	}
+	return task.getInfo()
+}
+
+// GetInfoWithDeferred is the programmatic example of "dmsetup info", but deferred.
+// It outputs some brief information about the device.
+func GetInfoWithDeferred(name string) (*Info, error) {
+	task, err := TaskCreateNamed(deviceInfo, name)
+	if task == nil {
+		return nil, err
+	}
+	if err := task.run(); err != nil {
+		return nil, err
+	}
+	return task.getInfoWithDeferred()
+}
+
+// GetDriverVersion is the programmatic example of "dmsetup version".
+// It outputs version information of the driver.
+func GetDriverVersion() (string, error) {
+	task := TaskCreate(deviceVersion)
+	if task == nil {
+		return "", fmt.Errorf("devicemapper: Can't create deviceVersion task")
+	}
+	if err := task.run(); err != nil {
+		return "", err
+	}
+	return task.getDriverVersion()
+}
+
+// GetStatus is the programmatic example of "dmsetup status".
+// It outputs status information for the specified device name.
+func GetStatus(name string) (uint64, uint64, string, string, error) {
+	task, err := TaskCreateNamed(deviceStatus, name)
+	if task == nil {
+		logrus.Debugf("devicemapper: GetStatus() Error TaskCreateNamed: %s", err)
+		return 0, 0, "", "", err
+	}
+	if err := task.run(); err != nil {
+		logrus.Debugf("devicemapper: GetStatus() Error Run: %s", err)
+		return 0, 0, "", "", err
+	}
+
+	devinfo, err := task.getInfo()
+	if err != nil {
+		logrus.Debugf("devicemapper: GetStatus() Error GetInfo: %s", err)
+		return 0, 0, "", "", err
+	}
+	if devinfo.Exists == 0 {
+		logrus.Debugf("devicemapper: GetStatus() Non existing device %s", name)
+		return 0, 0, "", "", fmt.Errorf("devicemapper: Non existing device %s", name)
+	}
+
+	_, start, length, targetType, params := task.getNextTarget(unsafe.Pointer(nil))
+	return start, length, targetType, params, nil
+}
+
+// GetTable is the programmatic example for "dmsetup table".
+// It outputs the current table for the specified device name.
+func GetTable(name string) (uint64, uint64, string, string, error) {
+	task, err := TaskCreateNamed(deviceTable, name)
+	if task == nil {
+		logrus.Debugf("devicemapper: GetTable() Error TaskCreateNamed: %s", err)
+		return 0, 0, "", "", err
+	}
+	if err := task.run(); err != nil {
+		logrus.Debugf("devicemapper: GetTable() Error Run: %s", err)
+		return 0, 0, "", "", err
+	}
+
+	devinfo, err := task.getInfo()
+	if err != nil {
+		logrus.Debugf("devicemapper: GetTable() Error GetInfo: %s", err)
+		return 0, 0, "", "", err
+	}
+	if devinfo.Exists == 0 {
+		logrus.Debugf("devicemapper: GetTable() Non existing device %s", name)
+		return 0, 0, "", "", fmt.Errorf("devicemapper: Non existing device %s", name)
+	}
+
+	_, start, length, targetType, params := task.getNextTarget(unsafe.Pointer(nil))
+	return start, length, targetType, params, nil
+}
+
+// SetTransactionID sets a transaction id for the specified device name.
+func SetTransactionID(poolName string, oldID uint64, newID uint64) error {
+	task, err := TaskCreateNamed(deviceTargetMsg, poolName)
+	if task == nil {
+		return err
+	}
+
+	if err := task.setSector(0); err != nil {
+		return fmt.Errorf("devicemapper: Can't set sector %s", err)
+	}
+
+	if err := task.setMessage(fmt.Sprintf("set_transaction_id %d %d", oldID, newID)); err != nil {
+		return fmt.Errorf("devicemapper: Can't set message %s", err)
+	}
+
+	if err := task.run(); err != nil {
+		return fmt.Errorf("devicemapper: Error running SetTransactionID %s", err)
+	}
+	return nil
+}
+
+// SuspendDevice is the programmatic example of "dmsetup suspend".
+// It suspends the specified device.
+func SuspendDevice(name string) error {
+	task, err := TaskCreateNamed(deviceSuspend, name)
+	if task == nil {
+		return err
+	}
+	if err := task.run(); err != nil {
+		return fmt.Errorf("devicemapper: Error running deviceSuspend %s", err)
+	}
+	return nil
+}
+
+// ResumeDevice is the programmatic example of "dmsetup resume".
+// It un-suspends the specified device.
+func ResumeDevice(name string) error {
+	task, err := TaskCreateNamed(deviceResume, name)
+	if task == nil {
+		return err
+	}
+
+	var cookie uint
+	if err := task.setCookie(&cookie, 0); err != nil {
+		return fmt.Errorf("devicemapper: Can't set cookie %s", err)
+	}
+	defer UdevWait(&cookie)
+
+	if err := task.run(); err != nil {
+		return fmt.Errorf("devicemapper: Error running deviceResume %s", err)
+	}
+
+	return nil
+}
+
+// CreateDevice creates a device with the specified poolName with the specified device id.
+func CreateDevice(poolName string, deviceID int) error {
+	logrus.Debugf("devicemapper: CreateDevice(poolName=%v, deviceID=%v)", poolName, deviceID)
+	task, err := TaskCreateNamed(deviceTargetMsg, poolName)
+	if task == nil {
+		return err
+	}
+
+	if err := task.setSector(0); err != nil {
+		return fmt.Errorf("devicemapper: Can't set sector %s", err)
+	}
+
+	if err := task.setMessage(fmt.Sprintf("create_thin %d", deviceID)); err != nil {
+		return fmt.Errorf("devicemapper: Can't set message %s", err)
+	}
+
+	dmSawExist = false // reset before the task is run
+	if err := task.run(); err != nil {
+		// Caller wants to know about ErrDeviceIDExists so that it can try with a different device id.
+		if dmSawExist {
+			return ErrDeviceIDExists
+		}
+
+		return fmt.Errorf("devicemapper: Error running CreateDevice %s", err)
+
+	}
+	return nil
+}
+
+// DeleteDevice deletes a device with the specified poolName with the specified device id.
+func DeleteDevice(poolName string, deviceID int) error {
+	task, err := TaskCreateNamed(deviceTargetMsg, poolName)
+	if task == nil {
+		return err
+	}
+
+	if err := task.setSector(0); err != nil {
+		return fmt.Errorf("devicemapper: Can't set sector %s", err)
+	}
+
+	if err := task.setMessage(fmt.Sprintf("delete %d", deviceID)); err != nil {
+		return fmt.Errorf("devicemapper: Can't set message %s", err)
+	}
+
+	dmSawBusy = false
+	if err := task.run(); err != nil {
+		if dmSawBusy {
+			return ErrBusy
+		}
+		return fmt.Errorf("devicemapper: Error running DeleteDevice %s", err)
+	}
+	return nil
+}
+
+// ActivateDevice activates the device identified by the specified
+// poolName, name and deviceID with the specified size.
+func ActivateDevice(poolName string, name string, deviceID int, size uint64) error {
+	return activateDevice(poolName, name, deviceID, size, "")
+}
+
+// ActivateDeviceWithExternal activates the device identified by the specified
+// poolName, name and deviceID with the specified size.
+func ActivateDeviceWithExternal(poolName string, name string, deviceID int, size uint64, external string) error {
+	return activateDevice(poolName, name, deviceID, size, external)
+}
+
+func activateDevice(poolName string, name string, deviceID int, size uint64, external string) error {
+	task, err := TaskCreateNamed(deviceCreate, name)
+	if task == nil {
+		return err
+	}
+
+	var params string
+	if len(external) > 0 {
+		params = fmt.Sprintf("%s %d %s", poolName, deviceID, external)
+	} else {
+		params = fmt.Sprintf("%s %d", poolName, deviceID)
+	}
+	if err := task.addTarget(0, size/512, "thin", params); err != nil {
+		return fmt.Errorf("devicemapper: Can't add target %s", err)
+	}
+	if err := task.setAddNode(addNodeOnCreate); err != nil {
+		return fmt.Errorf("devicemapper: Can't add node %s", err)
+	}
+
+	var cookie uint
+	if err := task.setCookie(&cookie, 0); err != nil {
+		return fmt.Errorf("devicemapper: Can't set cookie %s", err)
+	}
+
+	defer UdevWait(&cookie)
+
+	if err := task.run(); err != nil {
+		return fmt.Errorf("devicemapper: Error running deviceCreate (ActivateDevice) %s", err)
+	}
+
+	return nil
+}
+
+// CreateSnapDevice creates a snapshot based on the device identified by the baseName and baseDeviceId,
+func CreateSnapDevice(poolName string, deviceID int, baseName string, baseDeviceID int) error {
+	devinfo, _ := GetInfo(baseName)
+	doSuspend := devinfo != nil && devinfo.Exists != 0
+
+	if doSuspend {
+		if err := SuspendDevice(baseName); err != nil {
+			return err
+		}
+	}
+
+	task, err := TaskCreateNamed(deviceTargetMsg, poolName)
+	if task == nil {
+		if doSuspend {
+			ResumeDevice(baseName)
+		}
+		return err
+	}
+
+	if err := task.setSector(0); err != nil {
+		if doSuspend {
+			ResumeDevice(baseName)
+		}
+		return fmt.Errorf("devicemapper: Can't set sector %s", err)
+	}
+
+	if err := task.setMessage(fmt.Sprintf("create_snap %d %d", deviceID, baseDeviceID)); err != nil {
+		if doSuspend {
+			ResumeDevice(baseName)
+		}
+		return fmt.Errorf("devicemapper: Can't set message %s", err)
+	}
+
+	dmSawExist = false // reset before the task is run
+	if err := task.run(); err != nil {
+		if doSuspend {
+			ResumeDevice(baseName)
+		}
+		// Caller wants to know about ErrDeviceIDExists so that it can try with a different device id.
+		if dmSawExist {
+			return ErrDeviceIDExists
+		}
+
+		return fmt.Errorf("devicemapper: Error running deviceCreate (createSnapDevice) %s", err)
+
+	}
+
+	if doSuspend {
+		if err := ResumeDevice(baseName); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}