forked from moby/moby
/
driver.go
230 lines (190 loc) · 5.11 KB
/
driver.go
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// +build linux,amd64
package devmapper
import (
"fmt"
"github.com/dotcloud/docker/runtime/graphdriver"
"github.com/dotcloud/docker/utils"
"io/ioutil"
"os"
"path"
"strconv"
"strings"
)
func init() {
graphdriver.Register("devicemapper", Init)
}
// Placeholder interfaces, to be replaced
// at integration.
// End of placeholder interfaces.
type Driver struct {
*DeviceSet
home string
}
var Init = func(home string) (graphdriver.Driver, error) {
deviceSet, err := NewDeviceSet(home, true)
if err != nil {
return nil, err
}
d := &Driver{
DeviceSet: deviceSet,
home: home,
}
return d, nil
}
func (d *Driver) String() string {
return "devicemapper"
}
func (d *Driver) Status() [][2]string {
s := d.DeviceSet.Status()
status := [][2]string{
{"Pool Name", s.PoolName},
{"Data file", s.DataLoopback},
{"Metadata file", s.MetadataLoopback},
{"Data Space Used", fmt.Sprintf("%.1f Mb", float64(s.Data.Used)/(1024*1024))},
{"Data Space Total", fmt.Sprintf("%.1f Mb", float64(s.Data.Total)/(1024*1024))},
{"Metadata Space Used", fmt.Sprintf("%.1f Mb", float64(s.Metadata.Used)/(1024*1024))},
{"Metadata Space Total", fmt.Sprintf("%.1f Mb", float64(s.Metadata.Total)/(1024*1024))},
}
return status
}
func byteSizeFromString(arg string) (int64, error) {
digits := ""
rest := ""
last := strings.LastIndexAny(arg, "0123456789")
if last >= 0 {
digits = arg[:last+1]
rest = arg[last+1:]
}
val, err := strconv.ParseInt(digits, 10, 64)
if err != nil {
return val, err
}
rest = strings.ToLower(strings.TrimSpace(rest))
var multiplier int64 = 1
switch rest {
case "":
multiplier = 1
case "k", "kb":
multiplier = 1024
case "m", "mb":
multiplier = 1024 * 1024
case "g", "gb":
multiplier = 1024 * 1024 * 1024
case "t", "tb":
multiplier = 1024 * 1024 * 1024 * 1024
default:
return 0, fmt.Errorf("Unknown size unit: %s", rest)
}
return val * multiplier, nil
}
func (d *Driver) Operation(op string, args []string) error {
switch op {
case "trim-pool":
if len(args) != 0 {
return fmt.Errorf("Usage: trim-pool")
}
err := d.DeviceSet.TrimPool()
if err != nil {
return fmt.Errorf("Error trimming pool: %s", err.Error())
}
return nil
case "resize-pool":
if len(args) != 1 {
return fmt.Errorf("Usage: resize-pool NEW_SIZE")
}
size, err := byteSizeFromString(args[0])
if err != nil {
return fmt.Errorf("Invalid size: %s", args[0])
}
err = d.DeviceSet.ResizePool(size)
if err != nil {
return fmt.Errorf("Error resizing pool: %s", err.Error())
}
return nil
case "resize":
if len(args) != 2 {
return fmt.Errorf("Usage: resize IMAGE/CONTAINER NEW_SIZE")
}
size, err := byteSizeFromString(args[1])
if err != nil {
return fmt.Errorf("Invalid size: %s", args[0])
}
err = d.DeviceSet.ResizeDevice(args[0], size)
if err != nil {
return fmt.Errorf("Error resizing %s: %s", args[0], err.Error())
}
return nil
default:
return fmt.Errorf("Operation %s not supported", op)
}
}
func (d *Driver) Cleanup() error {
return d.DeviceSet.Shutdown()
}
func (d *Driver) Create(id, parent string) error {
if err := d.DeviceSet.AddDevice(id, parent); err != nil {
return err
}
mp := path.Join(d.home, "mnt", id)
if err := d.mount(id, mp); err != nil {
return err
}
if err := osMkdirAll(path.Join(mp, "rootfs"), 0755); err != nil && !osIsExist(err) {
return err
}
// Create an "id" file with the container/image id in it to help reconscruct this in case
// of later problems
if err := ioutil.WriteFile(path.Join(mp, "id"), []byte(id), 0600); err != nil {
return err
}
// We float this reference so that the next Get call can
// steal it, so we don't have to unmount
if err := d.DeviceSet.UnmountDevice(id, UnmountFloat); err != nil {
return err
}
return nil
}
func (d *Driver) Remove(id string) error {
if !d.DeviceSet.HasDevice(id) {
// Consider removing a non-existing device a no-op
// This is useful to be able to progress on container removal
// if the underlying device has gone away due to earlier errors
return nil
}
// Sink the float from create in case no Get() call was made
if err := d.DeviceSet.UnmountDevice(id, UnmountSink); err != nil {
return err
}
// This assumes the device has been properly Get/Put:ed and thus is unmounted
if err := d.DeviceSet.DeleteDevice(id); err != nil {
return err
}
mp := path.Join(d.home, "mnt", id)
if err := os.RemoveAll(mp); err != nil && !os.IsNotExist(err) {
return err
}
return nil
}
func (d *Driver) Get(id string) (string, error) {
mp := path.Join(d.home, "mnt", id)
if err := d.mount(id, mp); err != nil {
return "", err
}
return path.Join(mp, "rootfs"), nil
}
func (d *Driver) Put(id string) {
if err := d.DeviceSet.UnmountDevice(id, UnmountRegular); err != nil {
utils.Errorf("Warning: error unmounting device %s: %s\n", id, err)
}
}
func (d *Driver) mount(id, mountPoint string) error {
// Create the target directories if they don't exist
if err := osMkdirAll(mountPoint, 0755); err != nil && !osIsExist(err) {
return err
}
// Mount the device
return d.DeviceSet.MountDevice(id, mountPoint)
}
func (d *Driver) Exists(id string) bool {
return d.Devices[id] != nil
}