1 files changed, 142 insertions, 0 deletions
diff --git a/runtime/graphdriver/devmapper/driver.go b/runtime/graphdriver/devmapper/driver.go
new file mode 100644
index 0000000000..35fe883f26
--- /dev/null
+++ b/runtime/graphdriver/devmapper/driver.go
@@ -0,0 +1,142 @@
+// +build linux,amd64
+
+package devmapper
+
+import (
+	"fmt"
+	"github.com/dotcloud/docker/runtime/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, mountLabel 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
+}