docker: Make sure to umount the container if it's still mounted at

destruction

docker.go

@@ -67,10 +67,14 @@ func (docker *Docker) Destroy(container *Container) error {
 	if err := container.Stop(); err != nil {
 		return err
 	}
-	if err := os.RemoveAll(container.Root); err != nil {
+	if container.Filesystem.IsMounted() {
-		return err
+		if err := container.Filesystem.Umount(); err != nil {
+			log.Printf("Unable to umount container %v: %v", container.Id, err)
+		}
+	}
+	if err := os.RemoveAll(container.Root); err != nil {
+		log.Printf("Unable to remove filesystem for %v: %v", container.Id, err)
 	}
-
 	docker.containers.Remove(element)
 	return nil
 }

filesystem.go

@@ -58,6 +58,8 @@ func (fs *Filesystem) Umount() error {
 	if fs.IsMounted() {
 		return fmt.Errorf("Umount: Filesystem still mounted after calling umount(%v)", fs.RootFS)
 	}
+	// Even though we just unmounted the filesystem, AUFS will prevent deleting the mntpoint
+	// for some time. We'll just keep retrying until it succeeds.
 	for retries := 0; retries < 1000; retries++ {
 		err := os.Remove(fs.RootFS)
 		if err == nil {