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deviceset.go
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deviceset.go
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// +build linux
package devmapper
import (
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"path"
"path/filepath"
"strconv"
"strings"
"sync"
"syscall"
"time"
log "github.com/Sirupsen/logrus"
"github.com/docker/docker/daemon/graphdriver"
"github.com/docker/docker/pkg/devicemapper"
"github.com/docker/docker/pkg/parsers"
"github.com/docker/docker/pkg/units"
"github.com/docker/libcontainer/label"
)
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
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:"-"`
DeviceId int `json:"device_id"`
Size uint64 `json:"size"`
TransactionId uint64 `json:"transaction_id"`
Initialized bool `json:"initialized"`
devices *DeviceSet
mountCount int
mountPath string
// The global DeviceSet lock guarantees that we serialize all
// the calls to libdevmapper (which is not threadsafe), but we
// sometimes release that lock while sleeping. In that case
// this per-device lock is still held, protecting against
// other accesses to the device that we're doing the wait on.
//
// WARNING: In order to avoid AB-BA deadlocks when releasing
// the global lock while holding the per-device locks all
// device locks must be aquired *before* the device lock, and
// multiple device locks should be aquired parent before child.
lock sync.Mutex
}
type MetaData struct {
Devices map[string]*DevInfo `json:"Devices"`
devicesLock sync.Mutex // Protects all read/writes to Devices map
}
type DeviceSet struct {
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
metaDataLoopbackSize int64
baseFsSize uint64
filesystem string
mountOptions string
mkfsArgs []string
dataDevice string // block or loop dev
dataLoopFile string // loopback file, if used
metadataDevice string // block or loop dev
metadataLoopFile string // loopback file, if used
doBlkDiscard bool
thinpBlockSize uint32
thinPoolDevice string
Transaction `json:"-"`
}
type DiskUsage struct {
Used uint64
Total uint64
Available uint64
}
type Status struct {
PoolName string
DataFile string // actual block device for data
DataLoopback string // loopback file, if used
MetadataFile string // actual block device for metadata
MetadataLoopback string // loopback file, if used
Data DiskUsage
Metadata DiskUsage
SectorSize uint64
UdevSyncSupported bool
}
type DevStatus struct {
DeviceId int
Size uint64
TransactionId uint64
SizeInSectors uint64
MappedSectors uint64
HighestMappedSector uint64
}
func getDevName(name string) string {
return "/dev/mapper/" + name
}
func (info *DevInfo) Name() string {
hash := info.Hash
if hash == "" {
hash = "base"
}
return fmt.Sprintf("%s-%s", info.devices.devicePrefix, hash)
}
func (info *DevInfo) DevName() string {
return getDevName(info.Name())
}
func (devices *DeviceSet) loopbackDir() string {
return path.Join(devices.root, "devicemapper")
}
func (devices *DeviceSet) metadataDir() string {
return path.Join(devices.root, "metadata")
}
func (devices *DeviceSet) metadataFile(info *DevInfo) string {
file := info.Hash
if file == "" {
file = "base"
}
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)
}
func (devices *DeviceSet) oldMetadataFile() string {
return path.Join(devices.loopbackDir(), "json")
}
func (devices *DeviceSet) getPoolName() string {
if devices.thinPoolDevice == "" {
return devices.devicePrefix + "-pool"
}
return devices.thinPoolDevice
}
func (devices *DeviceSet) getPoolDevName() string {
return getDevName(devices.getPoolName())
}
func (devices *DeviceSet) hasImage(name string) bool {
dirname := devices.loopbackDir()
filename := path.Join(dirname, name)
_, err := os.Stat(filename)
return err == nil
}
// ensureImage creates a sparse file of <size> bytes at the path
// <root>/devicemapper/<name>.
// If the file already exists, it does nothing.
// Either way it returns the full path.
func (devices *DeviceSet) ensureImage(name string, size int64) (string, error) {
dirname := devices.loopbackDir()
filename := path.Join(dirname, name)
if err := os.MkdirAll(dirname, 0700); err != nil && !os.IsExist(err) {
return "", err
}
if _, err := os.Stat(filename); err != nil {
if !os.IsNotExist(err) {
return "", err
}
log.Debugf("Creating loopback file %s for device-manage use", filename)
file, err := os.OpenFile(filename, os.O_RDWR|os.O_CREATE, 0600)
if err != nil {
return "", err
}
defer file.Close()
if err = file.Truncate(size); err != nil {
return "", err
}
}
return filename, nil
}
func (devices *DeviceSet) allocateTransactionId() uint64 {
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 {
if err := os.RemoveAll(devices.metadataFile(info)); err != nil {
return fmt.Errorf("Error removing metadata file %s: %s", devices.metadataFile(info), err)
}
return nil
}
// Given json data and file path, write it to disk
func (devices *DeviceSet) writeMetaFile(jsonData []byte, filePath string) error {
tmpFile, err := ioutil.TempFile(devices.metadataDir(), ".tmp")
if err != nil {
return fmt.Errorf("Error creating metadata file: %s", err)
}
n, err := tmpFile.Write(jsonData)
if err != nil {
return fmt.Errorf("Error writing metadata to %s: %s", tmpFile.Name(), err)
}
if n < len(jsonData) {
return io.ErrShortWrite
}
if err := tmpFile.Sync(); err != nil {
return fmt.Errorf("Error syncing metadata file %s: %s", tmpFile.Name(), err)
}
if err := tmpFile.Close(); err != nil {
return fmt.Errorf("Error closing metadata file %s: %s", tmpFile.Name(), err)
}
if err := os.Rename(tmpFile.Name(), filePath); err != nil {
return fmt.Errorf("Error committing metadata file %s: %s", tmpFile.Name(), err)
}
return nil
}
func (devices *DeviceSet) saveMetadata(info *DevInfo) error {
jsonData, err := json.Marshal(info)
if err != nil {
return fmt.Errorf("Error encoding metadata to json: %s", err)
}
if err := devices.writeMetaFile(jsonData, devices.metadataFile(info)); err != nil {
return err
}
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()
info := devices.Devices[hash]
if info == nil {
info = devices.loadMetadata(hash)
if info == nil {
return nil, fmt.Errorf("Unknown device %s", hash)
}
devices.Devices[hash] = info
}
return info, nil
}
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 strings.HasPrefix(finfo.Name(), ".") {
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("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 metadata: %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: transactionId,
Initialized: false,
devices: devices,
}
devices.devicesLock.Lock()
devices.Devices[hash] = info
devices.devicesLock.Unlock()
if err := devices.saveMetadata(info); err != nil {
// Try to remove unused device
devices.devicesLock.Lock()
delete(devices.Devices, hash)
devices.devicesLock.Unlock()
return nil, err
}
return info, nil
}
func (devices *DeviceSet) activateDeviceIfNeeded(info *DevInfo) error {
log.Debugf("activateDeviceIfNeeded(%v)", info.Hash)
if devinfo, _ := devicemapper.GetInfo(info.Name()); devinfo != nil && devinfo.Exists != 0 {
return nil
}
return devicemapper.ActivateDevice(devices.getPoolDevName(), info.Name(), info.DeviceId, info.Size)
}
func (devices *DeviceSet) createFilesystem(info *DevInfo) error {
devname := info.DevName()
args := []string{}
for _, arg := range devices.mkfsArgs {
args = append(args, arg)
}
args = append(args, devname)
var err error
switch devices.filesystem {
case "xfs":
err = exec.Command("mkfs.xfs", args...).Run()
case "ext4":
err = exec.Command("mkfs.ext4", append([]string{"-E", "nodiscard,lazy_itable_init=0,lazy_journal_init=0"}, args...)...).Run()
if err != nil {
err = exec.Command("mkfs.ext4", append([]string{"-E", "nodiscard,lazy_itable_init=0"}, args...)...).Run()
}
if err != nil {
return err
}
err = exec.Command("tune2fs", append([]string{"-c", "-1", "-i", "0"}, devname)...).Run()
default:
err = fmt.Errorf("Unsupported filesystem type %s", devices.filesystem)
}
if err != nil {
return err
}
return nil
}
func (devices *DeviceSet) migrateOldMetaData() error {
// Migrate old metadata file
jsonData, err := ioutil.ReadFile(devices.oldMetadataFile())
if err != nil && !os.IsNotExist(err) {
return err
}
if jsonData != nil {
m := MetaData{Devices: make(map[string]*DevInfo)}
if err := json.Unmarshal(jsonData, &m); err != nil {
return err
}
for hash, info := range m.Devices {
info.Hash = hash
devices.saveMetadata(info)
}
if err := os.Rename(devices.oldMetadataFile(), devices.oldMetadataFile()+".migrated"); err != nil {
return err
}
}
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("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("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}
jsonData, err := ioutil.ReadFile(devices.metadataFile(info))
if err != nil {
return nil
}
if err := json.Unmarshal(jsonData, &info); err != nil {
return nil
}
return info
}
func (devices *DeviceSet) setupBaseImage() error {
oldInfo, _ := devices.lookupDevice("")
if oldInfo != nil && oldInfo.Initialized {
return nil
}
if oldInfo != nil && !oldInfo.Initialized {
log.Debugf("Removing uninitialized base image")
if err := devices.DeleteDevice(""); err != nil {
return err
}
}
if devices.thinPoolDevice != "" && oldInfo == nil {
_, transactionId, dataUsed, _, _, _, err := devices.poolStatus()
if err != nil {
return err
}
if dataUsed != 0 {
return fmt.Errorf("Unable to take ownership of thin-pool (%s) that already has used data blocks",
devices.thinPoolDevice)
}
if transactionId != 0 {
return fmt.Errorf("Unable to take ownership of thin-pool (%s) with non-zero transaction Id",
devices.thinPoolDevice)
}
}
log.Debugf("Initializing base device-mapper thin volume")
// Create initial device
info, err := devices.createRegisterDevice("")
if err != nil {
return err
}
log.Debugf("Creating filesystem on base device-mapper thin volume")
if err = devices.activateDeviceIfNeeded(info); err != nil {
return err
}
if err := devices.createFilesystem(info); err != nil {
return err
}
info.Initialized = true
if err = devices.saveMetadata(info); err != nil {
info.Initialized = false
return err
}
return nil
}
func setCloseOnExec(name string) {
if fileInfos, _ := ioutil.ReadDir("/proc/self/fd"); fileInfos != nil {
for _, i := range fileInfos {
link, _ := os.Readlink(filepath.Join("/proc/self/fd", i.Name()))
if link == name {
fd, err := strconv.Atoi(i.Name())
if err == nil {
syscall.CloseOnExec(fd)
}
}
}
}
}
func (devices *DeviceSet) DMLog(level int, file string, line int, dmError int, message string) {
if level >= devicemapper.LogLevelDebug {
// (vbatts) libdm debug is very verbose. If you're debugging libdm, you can
// comment out this check yourself
level = devicemapper.LogLevelInfo
}
// FIXME(vbatts) push this back into ./pkg/devicemapper/
log.Debugf("libdevmapper(%d): %s:%d (%d) %s", level, file, line, dmError, message)
}
func major(device uint64) uint64 {
return (device >> 8) & 0xfff
}
func minor(device uint64) uint64 {
return (device & 0xff) | ((device >> 12) & 0xfff00)
}
func (devices *DeviceSet) ResizePool(size int64) error {
dirname := devices.loopbackDir()
datafilename := path.Join(dirname, "data")
if len(devices.dataDevice) > 0 {
datafilename = devices.dataDevice
}
metadatafilename := path.Join(dirname, "metadata")
if len(devices.metadataDevice) > 0 {
metadatafilename = devices.metadataDevice
}
datafile, err := os.OpenFile(datafilename, os.O_RDWR, 0)
if datafile == nil {
return err
}
defer datafile.Close()
fi, err := datafile.Stat()
if fi == nil {
return err
}
if fi.Size() > size {
return fmt.Errorf("Can't shrink file")
}
dataloopback := devicemapper.FindLoopDeviceFor(datafile)
if dataloopback == nil {
return fmt.Errorf("Unable to find loopback mount for: %s", datafilename)
}
defer dataloopback.Close()
metadatafile, err := os.OpenFile(metadatafilename, os.O_RDWR, 0)
if metadatafile == nil {
return err
}
defer metadatafile.Close()
metadataloopback := devicemapper.FindLoopDeviceFor(metadatafile)
if metadataloopback == nil {
return fmt.Errorf("Unable to find loopback mount for: %s", metadatafilename)
}
defer metadataloopback.Close()
// Grow loopback file
if err := datafile.Truncate(size); err != nil {
return fmt.Errorf("Unable to grow loopback file: %s", err)
}
// Reload size for loopback device
if err := devicemapper.LoopbackSetCapacity(dataloopback); err != nil {
return fmt.Errorf("Unable to update loopback capacity: %s", err)
}
// Suspend the pool
if err := devicemapper.SuspendDevice(devices.getPoolName()); err != nil {
return fmt.Errorf("Unable to suspend pool: %s", err)
}
// Reload with the new block sizes
if err := devicemapper.ReloadPool(devices.getPoolName(), dataloopback, metadataloopback, devices.thinpBlockSize); err != nil {
return fmt.Errorf("Unable to reload pool: %s", err)
}
// Resume the pool
if err := devicemapper.ResumeDevice(devices.getPoolName()); err != nil {
return fmt.Errorf("Unable to resume pool: %s", err)
}
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("Unable to delete device: %s", err)
}
dinfo := &DevInfo{Hash: devices.DeviceIdHash}
if err := devices.removeMetadata(dinfo); err != nil {
log.Errorf("Unable to remove metadata: %s", err)
} else {
devices.markDeviceIdFree(devices.DeviceId)
}
if err := devices.removeTransactionMetaData(); err != nil {
log.Errorf("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("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 {
// For backward compatibility return success if file does
// not exist.
if os.IsNotExist(err) {
return nil
}
return err
}
return json.Unmarshal(jsonData, devices)
}
func (devices *DeviceSet) saveDeviceSetMetaData() error {
jsonData, err := json.Marshal(devices)
if err != nil {
return fmt.Errorf("Error encoding metadata to json: %s", err)
}
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 metadata: %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 metadata: %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 {
if os.Getenv("DEBUG") != "" {
devicemapper.LogInitVerbose(devicemapper.LogLevelDebug)
} else {
devicemapper.LogInitVerbose(devicemapper.LogLevelWarn)
}
// give ourselves to libdm as a log handler
devicemapper.LogInit(devices)
_, err := devicemapper.GetDriverVersion()
if err != nil {
// Can't even get driver version, assume not supported
return graphdriver.ErrNotSupported
}
// https://github.com/docker/docker/issues/4036
if supported := devicemapper.UdevSetSyncSupport(true); !supported {
log.Warnf("Udev sync is not supported. This will lead to unexpected behavior, data loss and errors")
}
log.Debugf("devicemapper: udev sync support: %v", devicemapper.UdevSyncSupported())
if err := os.MkdirAll(devices.metadataDir(), 0700); err != nil && !os.IsExist(err) {
return err
}
// Set the device prefix from the device id and inode of the docker root dir
st, err := os.Stat(devices.root)
if err != nil {
return fmt.Errorf("Error looking up dir %s: %s", devices.root, err)
}
sysSt := st.Sys().(*syscall.Stat_t)
// "reg-" stands for "regular file".
// In the future we might use "dev-" for "device file", etc.
// docker-maj,min[-inode] stands for:
// - Managed by docker
// - The target of this device is at major <maj> and minor <min>
// - If <inode> is defined, use that file inside the device as a loopback image. Otherwise use the device itself.
devices.devicePrefix = fmt.Sprintf("docker-%d:%d-%d", major(sysSt.Dev), minor(sysSt.Dev), sysSt.Ino)
log.Debugf("Generated prefix: %s", devices.devicePrefix)
// Check for the existence of the thin-pool device
log.Debugf("Checking for existence of the pool '%s'", devices.getPoolName())
info, err := devicemapper.GetInfo(devices.getPoolName())
if info == nil {
log.Debugf("Error device devicemapper.GetInfo: %s", err)
return err
}
// It seems libdevmapper opens this without O_CLOEXEC, and go exec will not close files
// that are not Close-on-exec, and lxc-start will die if it inherits any unexpected files,
// so we add this badhack to make sure it closes itself