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Ensure unmount before removing local volume. 

When there is an error unmounting a local volume, it is still possible
to call `Remove()` on the volume causing removal of the mounted
resources which is generally not desirable.

This ensures that resources are unmounted before attempting removal.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit db3576f8a0)
Signed-off-by: Victor Vieux <victorvieux@gmail.com>
This commit is contained in:
Brian Goff 2017-04-03 13:10:48 -04:00 committed by Victor Vieux
parent c4bd13b650
commit d1c9e9cfe9
2 changed files with 32 additions and 7 deletions
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4
integration-cli/docker_cli_daemon_test.go
View File

@ -88,8 +88,8 @@ func (s *DockerDaemonSuite) TestDaemonRestartWithVolumesRefs(c *check.C) {
s.d.Restart(c)
if _, err := s.d.Cmd("run", "-d", "--volumes-from", "volrestarttest1", "--name", "volrestarttest2", "busybox", "top"); err != nil {
c.Fatal(err)
if out, err := s.d.Cmd("run", "-d", "--volumes-from", "volrestarttest1", "--name", "volrestarttest2", "busybox", "top"); err != nil {
c.Fatal(err, out)
}
if out, err := s.d.Cmd("rm", "-fv", "volrestarttest2"); err != nil {

35
volume/local/local.go
View File

@ -218,6 +218,14 @@ func (r *Root) Remove(v volume.Volume) error {
return fmt.Errorf("unknown volume type %T", v)
}
if lv.active.count > 0 {
return fmt.Errorf("volume has active mounts")
}
if err := lv.unmount(); err != nil {
return err
}
realPath, err := filepath.EvalSymlinks(lv.path)
if err != nil {
if !os.IsNotExist(err) {
@ -306,6 +314,7 @@ func (v *localVolume) Path() string {
}
// Mount implements the localVolume interface, returning the data location.
// If there are any provided mount options, the resources will be mounted at this point
func (v *localVolume) Mount(id string) (string, error) {
v.m.Lock()
defer v.m.Unlock()
@ -321,19 +330,35 @@ func (v *localVolume) Mount(id string) (string, error) {
return v.path, nil
}
// Umount is for satisfying the localVolume interface and does not do anything in this driver.
// Unmount dereferences the id, and if it is the last reference will unmount any resources
// that were previously mounted.
func (v *localVolume) Unmount(id string) error {
v.m.Lock()
defer v.m.Unlock()
// Always decrement the count, even if the unmount fails
// Essentially docker doesn't care if this fails, it will send an error, but
// ultimately there's nothing that can be done. If we don't decrement the count
// this volume can never be removed until a daemon restart occurs.
if v.opts != nil {
v.active.count--
if v.active.count == 0 {
if err := mount.Unmount(v.path); err != nil {
v.active.count++
}
if v.active.count > 0 {
return nil
}
return v.unmount()
}
func (v *localVolume) unmount() error {
if v.opts != nil {
if err := mount.Unmount(v.path); err != nil {
if mounted, mErr := mount.Mounted(v.path); mounted || mErr != nil {
return errors.Wrapf(err, "error while unmounting volume path '%s'", v.path)
}
v.active.mounted = false
}
v.active.mounted = false
}
return nil
}