docker/graphdriver/devmapper/driver.go

137 строки
3.1 KiB
Go

// +build linux,amd64
package devmapper
import (
"fmt"
"github.com/dotcloud/docker/graphdriver"
"github.com/dotcloud/docker/utils"
"io/ioutil"
"os"
"path"
)
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 (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 {
// 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
}