func openNextAvailableLoopback(index int, sparseFile *os.File) (loopFile *os.File, err error) {
// Start looking for a free /dev/loop
for {
target := fmt.Sprintf("/dev/loop%d", index)
index++
fi, err := os.Stat(target)
if err != nil {
if os.IsNotExist(err) {
log.Errorf("There are no more loopback devices available.")
}
return nil, ErrAttachLoopbackDevice
}
if fi.Mode()&os.ModeDevice != os.ModeDevice {
log.Errorf("Loopback device %s is not a block device.", target)
continue
}
// OpenFile adds O_CLOEXEC
loopFile, err = os.OpenFile(target, os.O_RDWR, 0644)
if err != nil {
log.Errorf("Error openning loopback device: %s", err)
return nil, ErrAttachLoopbackDevice
}
// Try to attach to the loop file
if err := ioctlLoopSetFd(loopFile.Fd(), sparseFile.Fd()); err != nil {
loopFile.Close()
// If the error is EBUSY, then try the next loopback
if err != syscall.EBUSY {
log.Errorf("Cannot set up loopback device %s: %s", target, err)
return nil, ErrAttachLoopbackDevice
}
// Otherwise, we keep going with the loop
continue
}
// In case of success, we finished. Break the loop.
break
}
// This can't happen, but let's be sure
if loopFile == nil {
log.Errorf("Unreachable code reached! Error attaching %s to a loopback device.", sparseFile.Name())
return nil, ErrAttachLoopbackDevice
}
return loopFile, nil
}
func LoopbackSetCapacity(file *os.File) error {
if err := ioctlLoopSetCapacity(file.Fd(), 0); err != nil {
log.Errorf("Error loopbackSetCapacity: %s", err)
return ErrLoopbackSetCapacity
}
return nil
}
func GetBlockDeviceSize(file *os.File) (uint64, error) {
size, err := ioctlBlkGetSize64(file.Fd())
if err != nil {
log.Errorf("Error getblockdevicesize: %s", err)
return 0, ErrGetBlockSize
}
return uint64(size), nil
}
func getLoopbackBackingFile(file *os.File) (uint64, uint64, error) {
loopInfo, err := ioctlLoopGetStatus64(file.Fd())
if err != nil {
log.Errorf("Error get loopback backing file: %s", err)
return 0, 0, ErrGetLoopbackBackingFile
}
return loopInfo.loDevice, loopInfo.loInode, nil
}
func GetTotalUsedFds() int {
if fds, err := ioutil.ReadDir(fmt.Sprintf("/proc/%d/fd", os.Getpid())); err != nil {
log.Errorf("Error opening /proc/%d/fd: %s", os.Getpid(), err)
} else {
return len(fds)
}
return -1
}
func Unmount(target string) error {
if err := exec.Command("auplink", target, "flush").Run(); err != nil {
log.Errorf("[warning]: couldn't run auplink before unmount: %s", err)
}
if err := syscall.Unmount(target, 0); err != nil {
return err
}
return nil
}
// Matches returns true if relFilePath matches any of the patterns
func Matches(relFilePath string, patterns []string) (bool, error) {
for _, exclude := range patterns {
matched, err := filepath.Match(exclude, relFilePath)
if err != nil {
log.Errorf("Error matching: %s (pattern: %s)", relFilePath, exclude)
return false, err
}
if matched {
if filepath.Clean(relFilePath) == "." {
log.Errorf("Can't exclude whole path, excluding pattern: %s", exclude)
continue
}
log.Debugf("Skipping excluded path: %s", relFilePath)
return true, nil
}
}
return false, nil
}
// attachLoopDevice attaches the given sparse file to the next
// available loopback device. It returns an opened *os.File.
func attachLoopDevice(sparseName string) (loop *os.File, err error) {
// Try to retrieve the next available loopback device via syscall.
// If it fails, we discard error and start loopking for a
// loopback from index 0.
startIndex, err := getNextFreeLoopbackIndex()
if err != nil {
log.Debugf("Error retrieving the next available loopback: %s", err)
}
// OpenFile adds O_CLOEXEC
sparseFile, err := os.OpenFile(sparseName, os.O_RDWR, 0644)
if err != nil {
log.Errorf("Error openning sparse file %s: %s", sparseName, err)
return nil, ErrAttachLoopbackDevice
}
defer sparseFile.Close()
loopFile, err := openNextAvailableLoopback(startIndex, sparseFile)
if err != nil {
return nil, err
}
// Set the status of the loopback device
loopInfo := &LoopInfo64{
loFileName: stringToLoopName(loopFile.Name()),
loOffset: 0,
loFlags: LoFlagsAutoClear,
}
if err := ioctlLoopSetStatus64(loopFile.Fd(), loopInfo); err != nil {
log.Errorf("Cannot set up loopback device info: %s", err)
// If the call failed, then free the loopback device
if err := ioctlLoopClrFd(loopFile.Fd()); err != nil {
log.Errorf("Error while cleaning up the loopback device")
}
loopFile.Close()
return nil, ErrAttachLoopbackDevice
}
return loopFile, nil
}
// During cleanup aufs needs to unmount all mountpoints
func (a *Driver) Cleanup() error {
ids, err := loadIds(path.Join(a.rootPath(), "layers"))
if err != nil {
return err
}
for _, id := range ids {
if err := a.unmount(id); err != nil {
log.Errorf("Unmounting %s: %s", utils.TruncateID(id), err)
}
}
return mountpk.Unmount(a.root)
}
func (devices *DeviceSet) deactivateDevice(info *DevInfo) error {
log.Debugf("[devmapper] deactivateDevice(%s)", info.Hash)
defer log.Debugf("[devmapper] deactivateDevice END")
// Wait for the unmount to be effective,
// by watching the value of Info.OpenCount for the device
if err := devices.waitClose(info); err != nil {
log.Errorf("Warning: error waiting for device %s to close: %s", info.Hash, err)
}
devinfo, err := getInfo(info.Name())
if err != nil {
return err
}
if devinfo.Exists != 0 {
if err := devices.removeDeviceAndWait(info.Name()); err != nil {
return err
}
}
return nil
}
// Unmount and remove the dir information
func (a *Driver) Remove(id string) error {
// Protect the a.active from concurrent access
a.Lock()
defer a.Unlock()
if a.active[id] != 0 {
log.Errorf("Warning: removing active id %s", id)
}
// Make sure the dir is umounted first
if err := a.unmount(id); err != nil {
return err
}
tmpDirs := []string{
"mnt",
"diff",
}
// Atomically remove each directory in turn by first moving it out of the
// way (so that docker doesn't find it anymore) before doing removal of
// the whole tree.
for _, p := range tmpDirs {
realPath := path.Join(a.rootPath(), p, id)
tmpPath := path.Join(a.rootPath(), p, fmt.Sprintf("%s-removing", id))
if err := os.Rename(realPath, tmpPath); err != nil && !os.IsNotExist(err) {
return err
}
defer os.RemoveAll(tmpPath)
}
// Remove the layers file for the id
if err := os.Remove(path.Join(a.rootPath(), "layers", id)); err != nil && !os.IsNotExist(err) {
return err
}
return nil
}
func (d *Driver) Put(id string) {
if err := d.DeviceSet.UnmountDevice(id); err != nil {
log.Errorf("Warning: error unmounting device %s: %s", id, err)
}
}