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Merge pull request #5356 from alexlarsson/devmapper-no-mount-in-create

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devicemapper: Don't mount in Create()
This commit is contained in:
Guillaume J. Charmes 2014-04-24 08:19:59 -07:00
commit 56b779c321
3 changed files with 30 additions and 89 deletions
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44
daemon/graphdriver/devmapper/deviceset.go
View file

@ -35,12 +35,6 @@ type DevInfo struct {
mountCount int `json:"-"`
mountPath string `json:"-"`
// A floating mount means one reference is not owned and
// will be stolen by the next mount. This allows us to
// avoid unmounting directly after creation before the
// first get (since we need to mount to set up the device
// a bit first).
floating bool `json:"-"`
// The global DeviceSet lock guarantees that we serialize all
// the calls to libdevmapper (which is not threadsafe), but we
@ -94,14 +88,6 @@ type DevStatus struct {
HighestMappedSector uint64
}
type UnmountMode int
const (
UnmountRegular UnmountMode = iota
UnmountFloat
UnmountSink
)
func getDevName(name string) string {
return "/dev/mapper/" + name
}
@ -876,12 +862,7 @@ func (devices *DeviceSet) MountDevice(hash, path string, mountLabel string) erro
return fmt.Errorf("Trying to mount devmapper device in multple places (%s, %s)", info.mountPath, path)
}
if info.floating {
// Steal floating ref
info.floating = false
} else {
info.mountCount++
}
info.mountCount++
return nil
}
@ -903,13 +884,12 @@ func (devices *DeviceSet) MountDevice(hash, path string, mountLabel string) erro
info.mountCount = 1
info.mountPath = path
info.floating = false
return devices.setInitialized(info)
}
func (devices *DeviceSet) UnmountDevice(hash string, mode UnmountMode) error {
utils.Debugf("[devmapper] UnmountDevice(hash=%s, mode=%d)", hash, mode)
func (devices *DeviceSet) UnmountDevice(hash string) error {
utils.Debugf("[devmapper] UnmountDevice(hash=%s)", hash)
defer utils.Debugf("[devmapper] UnmountDevice END")
info, err := devices.lookupDevice(hash)
@ -923,24 +903,6 @@ func (devices *DeviceSet) UnmountDevice(hash string, mode UnmountMode) error {
devices.Lock()
defer devices.Unlock()
if mode == UnmountFloat {
if info.floating {
return fmt.Errorf("UnmountDevice: can't float floating reference %s\n", hash)
}
// Leave this reference floating
info.floating = true
return nil
}
if mode == UnmountSink {
if !info.floating {
// Someone already sunk this
return nil
}
// Otherwise, treat this as a regular unmount
}
if info.mountCount == 0 {
return fmt.Errorf("UnmountDevice: device not-mounted id %s\n", hash)
}

64
daemon/graphdriver/devmapper/driver.go
View file

@ -64,26 +64,6 @@ 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
}
@ -96,10 +76,6 @@ func (d *Driver) Remove(id string) error {
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
@ -115,28 +91,42 @@ func (d *Driver) Remove(id string) error {
func (d *Driver) Get(id string) (string, error) {
mp := path.Join(d.home, "mnt", id)
if err := d.mount(id, mp); err != nil {
// Create the target directories if they don't exist
if err := osMkdirAll(mp, 0755); err != nil && !osIsExist(err) {
return "", err
}
return path.Join(mp, "rootfs"), nil
// Mount the device
if err := d.DeviceSet.MountDevice(id, mp, ""); err != nil {
return "", err
}
rootFs := path.Join(mp, "rootfs")
if err := osMkdirAll(rootFs, 0755); err != nil && !osIsExist(err) {
d.DeviceSet.UnmountDevice(id)
return "", err
}
idFile := path.Join(mp, "id")
if _, err := osStat(idFile); err != nil && osIsNotExist(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(idFile, []byte(id), 0600); err != nil {
d.DeviceSet.UnmountDevice(id)
return "", err
}
}
return rootFs, nil
}
func (d *Driver) Put(id string) {
if err := d.DeviceSet.UnmountDevice(id, UnmountRegular); err != nil {
if err := d.DeviceSet.UnmountDevice(id); 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
return d.DeviceSet.HasDevice(id)
}

11
daemon/graphdriver/devmapper/driver_test.go
View file

@ -500,15 +500,10 @@ func TestDriverCreate(t *testing.T) {
calls.Assert(t,
"DmTaskCreate",
"DmTaskGetInfo",
"sysMount",
"DmTaskRun",
"DmTaskSetTarget",
"DmTaskSetSector",
"DmTaskSetCookie",
"DmUdevWait",
"DmTaskSetName",
"DmTaskSetMessage",
"DmTaskSetAddNode",
)
}()
@ -619,15 +614,10 @@ func TestDriverRemove(t *testing.T) {
calls.Assert(t,
"DmTaskCreate",
"DmTaskGetInfo",
"sysMount",
"DmTaskRun",
"DmTaskSetTarget",
"DmTaskSetSector",
"DmTaskSetCookie",
"DmUdevWait",
"DmTaskSetName",
"DmTaskSetMessage",
"DmTaskSetAddNode",
)
Mounted = func(mnt string) (bool, error) {
@ -650,7 +640,6 @@ func TestDriverRemove(t *testing.T) {
"DmTaskSetTarget",
"DmTaskSetAddNode",
"DmUdevWait",
"sysUnmount",
)
}()
runtime.GC()