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moby--moby/pkg/devicemapper/devmapper.go
Chris Dituri 9b584781ad Make pkg/devicemapper/ log messages with a common, consistent prefix.
Closes #16667

Uses the prefix "devicemapper:" for all the fmt and logrus error, debug, and info messages.

Signed-off-by: Chris Dituri <csdituri@gmail.com>
2015-12-14 21:35:15 -06:00

862 lines
24 KiB
Go

// +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")
ErrAttachLoopbackDevice = errors.New("loopback mounting failed")
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")
ErrGetLoopbackBackingFile = errors.New("Unable to get loopback backing file")
ErrLoopbackSetCapacity = errors.New("Unable set loopback capacity")
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
}
func getLoopbackBackingFile(file *os.File) (uint64, uint64, error) {
loopInfo, err := ioctlLoopGetStatus64(file.Fd())
if err != nil {
logrus.Errorf("devicemapper: Error get loopback backing file: %s", err)
return 0, 0, ErrGetLoopbackBackingFile
}
return loopInfo.loDevice, loopInfo.loInode, nil
}
// LoopbackSetCapacity reloads the size for the loopback device.
func LoopbackSetCapacity(file *os.File) error {
if err := ioctlLoopSetCapacity(file.Fd(), 0); err != nil {
logrus.Errorf("devicemapper: Error loopbackSetCapacity: %s", err)
return ErrLoopbackSetCapacity
}
return nil
}
// FindLoopDeviceFor returns a loopback device file for the specified file which
// is backing file of a loop back device.
func FindLoopDeviceFor(file *os.File) *os.File {
stat, err := file.Stat()
if err != nil {
return nil
}
targetInode := stat.Sys().(*syscall.Stat_t).Ino
targetDevice := stat.Sys().(*syscall.Stat_t).Dev
for i := 0; true; i++ {
path := fmt.Sprintf("/dev/loop%d", i)
file, err := os.OpenFile(path, os.O_RDWR, 0)
if err != nil {
if os.IsNotExist(err) {
return nil
}
// Ignore all errors until the first not-exist
// we want to continue looking for the file
continue
}
dev, inode, err := getLoopbackBackingFile(file)
if err == nil && dev == targetDevice && inode == targetInode {
return file
}
file.Close()
}
return nil
}
// 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.Debugf("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
}