// +build !exclude_graphdriver_aufs,linux

 package daemon

 
 import (

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/daemon/graphdriver"
 	"github.com/docker/docker/daemon/graphdriver/aufs"

 )
 
 // Given the graphdriver ad, if it is aufs, then migrate it.
 // If aufs driver is not built, this func is a noop.
 func migrateIfAufs(driver graphdriver.Driver, root string) error {
 	if ad, ok := driver.(*aufs.Driver); ok {

 		logrus.Debugf("Migrating existing containers")

 		if err := ad.Migrate(root, setupInitLayer); err != nil {

 			return err
 		}
 	}
 	return nil
 }