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Merge pull request #9258 from rhvgoyal/transaction-id-improvements

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devmapper fix usage of pool transaction id
This commit is contained in:
Vincent Batts 2014-12-11 12:58:18 -05:00
commit 74bbb93571
2 changed files with 465 additions and 129 deletions
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486
daemon/graphdriver/devmapper/deviceset.go
View file

@ -30,10 +30,19 @@ var (
DefaultDataLoopbackSize int64 = 100 * 1024 * 1024 * 1024
DefaultMetaDataLoopbackSize int64 = 2 * 1024 * 1024 * 1024
DefaultBaseFsSize uint64 = 10 * 1024 * 1024 * 1024
DefaultThinpBlockSize uint32 = 128 // 64K = 128 512b sectors
DefaultThinpBlockSize uint32 = 128 // 64K = 128 512b sectors
MaxDeviceId int = 0xffffff // 24 bit, pool limit
DeviceIdMapSz int = (MaxDeviceId + 1) / 8
)
const deviceSetMetaFile string = "deviceset-metadata"
const transactionMetaFile string = "transaction-metadata"
type Transaction struct {
OpenTransactionId uint64 `json:"open_transaction_id"`
DeviceIdHash string `json:"device_hash"`
DeviceId int `json:"device_id"`
}
type DevInfo struct {
Hash string `json:"-"`
@ -65,13 +74,13 @@ type MetaData struct {
}
type DeviceSet struct {
MetaData `json:"-"`
sync.Mutex `json:"-"` // Protects Devices map and serializes calls into libdevmapper
root string
devicePrefix string
TransactionId uint64 `json:"-"`
NewTransactionId uint64 `json:"-"`
NextDeviceId int `json:"next_device_id"`
MetaData `json:"-"`
sync.Mutex `json:"-"` // Protects Devices map and serializes calls into libdevmapper
root string
devicePrefix string
TransactionId uint64 `json:"-"`
NextDeviceId int `json:"next_device_id"`
deviceIdMap []byte
// Options
dataLoopbackSize int64
@ -85,6 +94,7 @@ type DeviceSet struct {
doBlkDiscard bool
thinpBlockSize uint32
thinPoolDevice string
Transaction `json:"-"`
}
type DiskUsage struct {
@ -142,6 +152,10 @@ func (devices *DeviceSet) metadataFile(info *DevInfo) string {
return path.Join(devices.metadataDir(), file)
}
func (devices *DeviceSet) transactionMetaFile() string {
return path.Join(devices.metadataDir(), transactionMetaFile)
}
func (devices *DeviceSet) deviceSetMetaFile() string {
return path.Join(devices.metadataDir(), deviceSetMetaFile)
}
@ -200,8 +214,16 @@ func (devices *DeviceSet) ensureImage(name string, size int64) (string, error) {
}
func (devices *DeviceSet) allocateTransactionId() uint64 {
devices.NewTransactionId = devices.NewTransactionId + 1
return devices.NewTransactionId
devices.OpenTransactionId = devices.TransactionId + 1
return devices.OpenTransactionId
}
func (devices *DeviceSet) updatePoolTransactionId() error {
if err := devicemapper.SetTransactionId(devices.getPoolDevName(), devices.TransactionId, devices.OpenTransactionId); err != nil {
return fmt.Errorf("Error setting devmapper transaction ID: %s", err)
}
devices.TransactionId = devices.OpenTransactionId
return nil
}
func (devices *DeviceSet) removeMetadata(info *DevInfo) error {
@ -246,16 +268,33 @@ func (devices *DeviceSet) saveMetadata(info *DevInfo) error {
if err := devices.writeMetaFile(jsonData, devices.metadataFile(info)); err != nil {
return err
}
if devices.NewTransactionId != devices.TransactionId {
if err = devicemapper.SetTransactionId(devices.getPoolDevName(), devices.TransactionId, devices.NewTransactionId); err != nil {
return fmt.Errorf("Error setting devmapper transition ID: %s", err)
}
devices.TransactionId = devices.NewTransactionId
}
return nil
}
func (devices *DeviceSet) markDeviceIdUsed(deviceId int) {
var mask byte
i := deviceId % 8
mask = 1 << uint(i)
devices.deviceIdMap[deviceId/8] = devices.deviceIdMap[deviceId/8] | mask
}
func (devices *DeviceSet) markDeviceIdFree(deviceId int) {
var mask byte
i := deviceId % 8
mask = ^(1 << uint(i))
devices.deviceIdMap[deviceId/8] = devices.deviceIdMap[deviceId/8] & mask
}
func (devices *DeviceSet) isDeviceIdFree(deviceId int) bool {
var mask byte
i := deviceId % 8
mask = (1 << uint(i))
if (devices.deviceIdMap[deviceId/8] & mask) != 0 {
return false
}
return true
}
func (devices *DeviceSet) lookupDevice(hash string) (*DevInfo, error) {
devices.devicesLock.Lock()
defer devices.devicesLock.Unlock()
@ -271,13 +310,91 @@ func (devices *DeviceSet) lookupDevice(hash string) (*DevInfo, error) {
return info, nil
}
func (devices *DeviceSet) registerDevice(id int, hash string, size uint64) (*DevInfo, error) {
func (devices *DeviceSet) deviceFileWalkFunction(path string, finfo os.FileInfo) error {
// Skip some of the meta files which are not device files.
if strings.HasSuffix(finfo.Name(), ".migrated") {
log.Debugf("Skipping file %s", path)
return nil
}
if finfo.Name() == deviceSetMetaFile {
log.Debugf("Skipping file %s", path)
return nil
}
log.Debugf("Loading data for file %s", path)
hash := finfo.Name()
if hash == "base" {
hash = ""
}
dinfo := devices.loadMetadata(hash)
if dinfo == nil {
return fmt.Errorf("Error loading device metadata file %s", hash)
}
if dinfo.DeviceId > MaxDeviceId {
log.Errorf("Warning: Ignoring Invalid DeviceId=%d", dinfo.DeviceId)
return nil
}
devices.Lock()
devices.markDeviceIdUsed(dinfo.DeviceId)
devices.Unlock()
log.Debugf("Added deviceId=%d to DeviceIdMap", dinfo.DeviceId)
return nil
}
func (devices *DeviceSet) constructDeviceIdMap() error {
log.Debugf("[deviceset] constructDeviceIdMap()")
defer log.Debugf("[deviceset] constructDeviceIdMap() END")
var scan = func(path string, info os.FileInfo, err error) error {
if err != nil {
log.Debugf("Can't walk the file %s", path)
return nil
}
// Skip any directories
if info.IsDir() {
return nil
}
return devices.deviceFileWalkFunction(path, info)
}
return filepath.Walk(devices.metadataDir(), scan)
}
func (devices *DeviceSet) unregisterDevice(id int, hash string) error {
log.Debugf("unregisterDevice(%v, %v)", id, hash)
info := &DevInfo{
Hash: hash,
DeviceId: id,
}
devices.devicesLock.Lock()
delete(devices.Devices, hash)
devices.devicesLock.Unlock()
if err := devices.removeMetadata(info); err != nil {
log.Debugf("Error removing meta data: %s", err)
return err
}
return nil
}
func (devices *DeviceSet) registerDevice(id int, hash string, size uint64, transactionId uint64) (*DevInfo, error) {
log.Debugf("registerDevice(%v, %v)", id, hash)
info := &DevInfo{
Hash: hash,
DeviceId: id,
Size: size,
TransactionId: devices.allocateTransactionId(),
TransactionId: transactionId,
Initialized: false,
devices: devices,
}
@ -340,19 +457,8 @@ func (devices *DeviceSet) createFilesystem(info *DevInfo) error {
return nil
}
func (devices *DeviceSet) initMetaData() error {
_, _, _, params, err := devicemapper.GetStatus(devices.getPoolName())
if err != nil {
return err
}
if _, err := fmt.Sscanf(params, "%d", &devices.TransactionId); err != nil {
return err
}
devices.NewTransactionId = devices.TransactionId
func (devices *DeviceSet) migrateOldMetaData() error {
// Migrate old metadatafile
jsonData, err := ioutil.ReadFile(devices.oldMetadataFile())
if err != nil && !os.IsNotExist(err) {
return err
@ -367,11 +473,7 @@ func (devices *DeviceSet) initMetaData() error {
for hash, info := range m.Devices {
info.Hash = hash
// If the transaction id is larger than the actual one we lost the device due to some crash
if info.TransactionId <= devices.TransactionId {
devices.saveMetadata(info)
}
devices.saveMetadata(info)
}
if err := os.Rename(devices.oldMetadataFile(), devices.oldMetadataFile()+".migrated"); err != nil {
return err
@ -382,6 +484,149 @@ func (devices *DeviceSet) initMetaData() error {
return nil
}
func (devices *DeviceSet) initMetaData() error {
if err := devices.migrateOldMetaData(); err != nil {
return err
}
_, transactionId, _, _, _, _, err := devices.poolStatus()
if err != nil {
return err
}
devices.TransactionId = transactionId
if err := devices.constructDeviceIdMap(); err != nil {
return err
}
if err := devices.processPendingTransaction(); err != nil {
return err
}
return nil
}
func (devices *DeviceSet) incNextDeviceId() {
// Ids are 24bit, so wrap around
devices.NextDeviceId = (devices.NextDeviceId + 1) & MaxDeviceId
}
func (devices *DeviceSet) getNextFreeDeviceId() (int, error) {
devices.incNextDeviceId()
for i := 0; i <= MaxDeviceId; i++ {
if devices.isDeviceIdFree(devices.NextDeviceId) {
devices.markDeviceIdUsed(devices.NextDeviceId)
return devices.NextDeviceId, nil
}
devices.incNextDeviceId()
}
return 0, fmt.Errorf("Unable to find a free device Id")
}
func (devices *DeviceSet) createRegisterDevice(hash string) (*DevInfo, error) {
deviceId, err := devices.getNextFreeDeviceId()
if err != nil {
return nil, err
}
if err := devices.openTransaction(hash, deviceId); err != nil {
log.Debugf("Error opening transaction hash = %s deviceId = %d", hash, deviceId)
devices.markDeviceIdFree(deviceId)
return nil, err
}
for {
if err := devicemapper.CreateDevice(devices.getPoolDevName(), deviceId); err != nil {
if devicemapper.DeviceIdExists(err) {
// Device Id already exists. This should not
// happen. Now we have a mechianism to find
// a free device Id. So something is not right.
// Give a warning and continue.
log.Errorf("Warning: Device Id %d exists in pool but it is supposed to be unused", deviceId)
deviceId, err = devices.getNextFreeDeviceId()
if err != nil {
return nil, err
}
// Save new device id into transaction
devices.refreshTransaction(deviceId)
continue
}
log.Debugf("Error creating device: %s", err)
devices.markDeviceIdFree(deviceId)
return nil, err
}
break
}
log.Debugf("Registering device (id %v) with FS size %v", deviceId, devices.baseFsSize)
info, err := devices.registerDevice(deviceId, hash, devices.baseFsSize, devices.OpenTransactionId)
if err != nil {
_ = devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
return nil, err
}
if err := devices.closeTransaction(); err != nil {
devices.unregisterDevice(deviceId, hash)
devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
return nil, err
}
return info, nil
}
func (devices *DeviceSet) createRegisterSnapDevice(hash string, baseInfo *DevInfo) error {
deviceId, err := devices.getNextFreeDeviceId()
if err != nil {
return err
}
if err := devices.openTransaction(hash, deviceId); err != nil {
log.Debugf("Error opening transaction hash = %s deviceId = %d", hash, deviceId)
devices.markDeviceIdFree(deviceId)
return err
}
for {
if err := devicemapper.CreateSnapDevice(devices.getPoolDevName(), deviceId, baseInfo.Name(), baseInfo.DeviceId); err != nil {
if devicemapper.DeviceIdExists(err) {
// Device Id already exists. This should not
// happen. Now we have a mechianism to find
// a free device Id. So something is not right.
// Give a warning and continue.
log.Errorf("Warning: Device Id %d exists in pool but it is supposed to be unused", deviceId)
deviceId, err = devices.getNextFreeDeviceId()
if err != nil {
return err
}
// Save new device id into transaction
devices.refreshTransaction(deviceId)
continue
}
log.Debugf("Error creating snap device: %s", err)
devices.markDeviceIdFree(deviceId)
return err
}
break
}
if _, err := devices.registerDevice(deviceId, hash, baseInfo.Size, devices.OpenTransactionId); err != nil {
devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
log.Debugf("Error registering device: %s", err)
return err
}
if err := devices.closeTransaction(); err != nil {
devices.unregisterDevice(deviceId, hash)
devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
devices.markDeviceIdFree(deviceId)
return err
}
return nil
}
func (devices *DeviceSet) loadMetadata(hash string) *DevInfo {
info := &DevInfo{Hash: hash, devices: devices}
@ -394,11 +639,6 @@ func (devices *DeviceSet) loadMetadata(hash string) *DevInfo {
return nil
}
// If the transaction id is larger than the actual one we lost the device due to some crash
if info.TransactionId > devices.TransactionId {
return nil
}
return info
}
@ -410,7 +650,7 @@ func (devices *DeviceSet) setupBaseImage() error {
if oldInfo != nil && !oldInfo.Initialized {
log.Debugf("Removing uninitialized base image")
if err := devices.deleteDevice(oldInfo); err != nil {
if err := devices.DeleteDevice(""); err != nil {
return err
}
}
@ -432,20 +672,9 @@ func (devices *DeviceSet) setupBaseImage() error {
log.Debugf("Initializing base device-mapper thin volume")
id := devices.NextDeviceId
// Create initial device
if err := devicemapper.CreateDevice(devices.getPoolDevName(), &id); err != nil {
return err
}
// Ids are 24bit, so wrap around
devices.NextDeviceId = (id + 1) & 0xffffff
log.Debugf("Registering base device (id %v) with FS size %v", id, devices.baseFsSize)
info, err := devices.registerDevice(id, "", devices.baseFsSize)
info, err := devices.createRegisterDevice("")
if err != nil {
_ = devicemapper.DeleteDevice(devices.getPoolDevName(), id)
return err
}
@ -571,6 +800,90 @@ func (devices *DeviceSet) ResizePool(size int64) error {
return nil
}
func (devices *DeviceSet) loadTransactionMetaData() error {
jsonData, err := ioutil.ReadFile(devices.transactionMetaFile())
if err != nil {
// There is no active transaction. This will be the case
// during upgrade.
if os.IsNotExist(err) {
devices.OpenTransactionId = devices.TransactionId
return nil
}
return err
}
json.Unmarshal(jsonData, &devices.Transaction)
return nil
}
func (devices *DeviceSet) saveTransactionMetaData() error {
jsonData, err := json.Marshal(&devices.Transaction)
if err != nil {
return fmt.Errorf("Error encoding metadata to json: %s", err)
}
return devices.writeMetaFile(jsonData, devices.transactionMetaFile())
}
func (devices *DeviceSet) removeTransactionMetaData() error {
if err := os.RemoveAll(devices.transactionMetaFile()); err != nil {
return err
}
return nil
}
func (devices *DeviceSet) rollbackTransaction() error {
log.Debugf("Rolling back open transaction: TransactionId=%d hash=%s device_id=%d", devices.OpenTransactionId, devices.DeviceIdHash, devices.DeviceId)
// A device id might have already been deleted before transaction
// closed. In that case this call will fail. Just leave a message
// in case of failure.
if err := devicemapper.DeleteDevice(devices.getPoolDevName(), devices.DeviceId); err != nil {
log.Errorf("Warning: Unable to delete device: %s", err)
}
dinfo := &DevInfo{Hash: devices.DeviceIdHash}
if err := devices.removeMetadata(dinfo); err != nil {
log.Errorf("Warning: Unable to remove meta data: %s", err)
} else {
devices.markDeviceIdFree(devices.DeviceId)
}
if err := devices.removeTransactionMetaData(); err != nil {
log.Errorf("Warning: Unable to remove transaction meta file %s: %s", devices.transactionMetaFile(), err)
}
return nil
}
func (devices *DeviceSet) processPendingTransaction() error {
if err := devices.loadTransactionMetaData(); err != nil {
return err
}
// If there was open transaction but pool transaction Id is same
// as open transaction Id, nothing to roll back.
if devices.TransactionId == devices.OpenTransactionId {
return nil
}
// If open transaction Id is less than pool transaction Id, something
// is wrong. Bail out.
if devices.OpenTransactionId < devices.TransactionId {
log.Errorf("Warning: Open Transaction id %d is less than pool transaction id %d", devices.OpenTransactionId, devices.TransactionId)
return nil
}
// Pool transaction Id is not same as open transaction. There is
// a transaction which was not completed.
if err := devices.rollbackTransaction(); err != nil {
return fmt.Errorf("Rolling back open transaction failed: %s", err)
}
devices.OpenTransactionId = devices.TransactionId
return nil
}
func (devices *DeviceSet) loadDeviceSetMetaData() error {
jsonData, err := ioutil.ReadFile(devices.deviceSetMetaFile())
if err != nil {
@ -594,6 +907,32 @@ func (devices *DeviceSet) saveDeviceSetMetaData() error {
return devices.writeMetaFile(jsonData, devices.deviceSetMetaFile())
}
func (devices *DeviceSet) openTransaction(hash string, DeviceId int) error {
devices.allocateTransactionId()
devices.DeviceIdHash = hash
devices.DeviceId = DeviceId
if err := devices.saveTransactionMetaData(); err != nil {
return fmt.Errorf("Error saving transaction meta data: %s", err)
}
return nil
}
func (devices *DeviceSet) refreshTransaction(DeviceId int) error {
devices.DeviceId = DeviceId
if err := devices.saveTransactionMetaData(); err != nil {
return fmt.Errorf("Error saving transaction meta data: %s", err)
}
return nil
}
func (devices *DeviceSet) closeTransaction() error {
if err := devices.updatePoolTransactionId(); err != nil {
log.Debugf("Failed to close Transaction")
return err
}
return nil
}
func (devices *DeviceSet) initDevmapper(doInit bool) error {
// give ourselves to libdm as a log handler
devicemapper.LogInit(devices)
@ -744,6 +1083,9 @@ func (devices *DeviceSet) initDevmapper(doInit bool) error {
}
func (devices *DeviceSet) AddDevice(hash, baseHash string) error {
log.Debugf("[deviceset] AddDevice() hash=%s basehash=%s", hash, baseHash)
defer log.Debugf("[deviceset] AddDevice END")
baseInfo, err := devices.lookupDevice(baseHash)
if err != nil {
return err
@ -759,21 +1101,10 @@ func (devices *DeviceSet) AddDevice(hash, baseHash string) error {
return fmt.Errorf("device %s already exists", hash)
}
deviceId := devices.NextDeviceId
if err := devicemapper.CreateSnapDevice(devices.getPoolDevName(), &deviceId, baseInfo.Name(), baseInfo.DeviceId); err != nil {
log.Debugf("Error creating snap device: %s", err)
if err := devices.createRegisterSnapDevice(hash, baseInfo); err != nil {
return err
}
// Ids are 24bit, so wrap around
devices.NextDeviceId = (deviceId + 1) & 0xffffff
if _, err := devices.registerDevice(deviceId, hash, baseInfo.Size); err != nil {
devicemapper.DeleteDevice(devices.getPoolDevName(), deviceId)
log.Debugf("Error registering device: %s", err)
return err
}
return nil
}
@ -797,24 +1128,26 @@ func (devices *DeviceSet) deleteDevice(info *DevInfo) error {
}
}
if err := devices.openTransaction(info.Hash, info.DeviceId); err != nil {
log.Debugf("Error opening transaction hash = %s deviceId = %d", "", info.DeviceId)
return err
}
if err := devicemapper.DeleteDevice(devices.getPoolDevName(), info.DeviceId); err != nil {
log.Debugf("Error deleting device: %s", err)
return err
}
devices.allocateTransactionId()
devices.devicesLock.Lock()
delete(devices.Devices, info.Hash)
devices.devicesLock.Unlock()
if err := devices.removeMetadata(info); err != nil {
devices.devicesLock.Lock()
devices.Devices[info.Hash] = info
devices.devicesLock.Unlock()
log.Debugf("Error removing meta data: %s", err)
if err := devices.unregisterDevice(info.DeviceId, info.Hash); err != nil {
return err
}
if err := devices.closeTransaction(); err != nil {
return err
}
devices.markDeviceIdFree(info.DeviceId)
return nil
}
@ -1255,6 +1588,7 @@ func NewDeviceSet(root string, doInit bool, options []string) (*DeviceSet, error
filesystem: "ext4",
doBlkDiscard: true,
thinpBlockSize: DefaultThinpBlockSize,
deviceIdMap: make([]byte, DeviceIdMapSz),
}
foundBlkDiscard := false

108
pkg/devicemapper/devmapper.go
View file

@ -67,6 +67,7 @@ var (
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")
dmSawBusy bool
dmSawExist bool
@ -97,6 +98,16 @@ type (
AddNodeType int
)
// 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)
@ -528,33 +539,29 @@ func ResumeDevice(name string) error {
return nil
}
func CreateDevice(poolName string, deviceId *int) error {
log.Debugf("[devmapper] CreateDevice(poolName=%v, deviceId=%v)", poolName, *deviceId)
func CreateDevice(poolName string, deviceId int) error {
log.Debugf("[devmapper] CreateDevice(poolName=%v, deviceId=%v)", poolName, deviceId)
task, err := TaskCreateNamed(DeviceTargetMsg, poolName)
if task == nil {
return err
}
for {
task, err := TaskCreateNamed(DeviceTargetMsg, poolName)
if task == nil {
return err
}
if err := task.SetSector(0); err != nil {
return fmt.Errorf("Can't set sector %s", err)
}
if err := task.SetSector(0); err != nil {
return fmt.Errorf("Can't set sector %s", err)
}
if err := task.SetMessage(fmt.Sprintf("create_thin %d", deviceId)); err != nil {
return fmt.Errorf("Can't set message %s", err)
}
if err := task.SetMessage(fmt.Sprintf("create_thin %d", *deviceId)); err != nil {
return fmt.Errorf("Can't set message %s", err)
}
dmSawExist = false // reset before the task is run
if err := task.Run(); err != nil {
if dmSawExist {
// Already exists, try next id
*deviceId++
continue
}
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
} else {
return fmt.Errorf("Error running CreateDevice %s", err)
}
break
}
return nil
}
@ -607,7 +614,7 @@ func ActivateDevice(poolName string, name string, deviceId int, size uint64) err
return nil
}
func CreateSnapDevice(poolName string, deviceId *int, baseName string, baseDeviceId int) error {
func CreateSnapDevice(poolName string, deviceId int, baseName string, baseDeviceId int) error {
devinfo, _ := GetInfo(baseName)
doSuspend := devinfo != nil && devinfo.Exists != 0
@ -617,44 +624,39 @@ func CreateSnapDevice(poolName string, deviceId *int, baseName string, baseDevic
}
}
for {
task, err := TaskCreateNamed(DeviceTargetMsg, poolName)
if task == nil {
if doSuspend {
ResumeDevice(baseName)
}
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("Can't set sector %s", err)
if err := task.SetSector(0); err != nil {
if doSuspend {
ResumeDevice(baseName)
}
return fmt.Errorf("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("Can't set message %s", err)
if err := task.SetMessage(fmt.Sprintf("create_snap %d %d", deviceId, baseDeviceId)); err != nil {
if doSuspend {
ResumeDevice(baseName)
}
return fmt.Errorf("Can't set message %s", err)
}
dmSawExist = false // reset before the task is run
if err := task.Run(); err != nil {
if dmSawExist {
// Already exists, try next id
*deviceId++
continue
}
if doSuspend {
ResumeDevice(baseName)
}
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
} else {
return fmt.Errorf("Error running DeviceCreate (createSnapDevice) %s", err)
}
break
}
if doSuspend {