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Merge pull request #22168 from cpuguy83/22116_hack_in_layer_refcounts

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Add refcounts to graphdrivers that use fsdiff
Upstream-commit: 8a0d2d8e57a4825fb21c0f8ef91bef513beebc35
Component: engine
This commit is contained in:
David Calavera
2016-04-22 15:17:12 -07:00
parent acc7b1d2d7 f8ddc00d73
commit 76c8648306
4 changed files with 78 additions and 0 deletions
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15
components/engine/daemon/graphdriver/devmapper/driver.go
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@ -28,6 +28,7 @@ type Driver struct {
home string
uidMaps []idtools.IDMap
gidMaps []idtools.IDMap
ctr *graphdriver.RefCounter
}
// Init creates a driver with the given home and the set of options.
@ -46,6 +47,7 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
home: home,
uidMaps: uidMaps,
gidMaps: gidMaps,
ctr: graphdriver.NewRefCounter(),
}
return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil
@ -157,26 +159,35 @@ func (d *Driver) Remove(id string) error {
// Get mounts a device with given id into the root filesystem
func (d *Driver) Get(id, mountLabel string) (string, error) {
mp := path.Join(d.home, "mnt", id)
if count := d.ctr.Increment(id); count > 1 {
return mp, nil
}
uid, gid, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
if err != nil {
d.ctr.Decrement(id)
return "", err
}
// Create the target directories if they don't exist
if err := idtools.MkdirAllAs(path.Join(d.home, "mnt"), 0755, uid, gid); err != nil && !os.IsExist(err) {
d.ctr.Decrement(id)
return "", err
}
if err := idtools.MkdirAs(mp, 0755, uid, gid); err != nil && !os.IsExist(err) {
d.ctr.Decrement(id)
return "", err
}
// Mount the device
if err := d.DeviceSet.MountDevice(id, mp, mountLabel); err != nil {
d.ctr.Decrement(id)
return "", err
}
rootFs := path.Join(mp, "rootfs")
if err := idtools.MkdirAllAs(rootFs, 0755, uid, gid); err != nil && !os.IsExist(err) {
d.ctr.Decrement(id)
d.DeviceSet.UnmountDevice(id, mp)
return "", err
}
@ -186,6 +197,7 @@ func (d *Driver) Get(id, mountLabel string) (string, error) {
// Create an "id" file with the container/image id in it to help reconstruct this in case
// of later problems
if err := ioutil.WriteFile(idFile, []byte(id), 0600); err != nil {
d.ctr.Decrement(id)
d.DeviceSet.UnmountDevice(id, mp)
return "", err
}
@ -196,6 +208,9 @@ func (d *Driver) Get(id, mountLabel string) (string, error) {
// Put unmounts a device and removes it.
func (d *Driver) Put(id string) error {
if count := d.ctr.Decrement(id); count > 0 {
return nil
}
mp := path.Join(d.home, "mnt", id)
err := d.DeviceSet.UnmountDevice(id, mp)
if err != nil {