@@ -505,7 +505,7 @@ func NewDaemon(config *config.Config, registryService registry.Service, containe

 	}

 	// set up the tmpDir to use a canonical path

-	tmp, err := tempDir(config.Root, rootUID, rootGID)

+	tmp, err := prepareTempDir(config.Root, rootUID, rootGID)

 	if err != nil {

 		return nil, fmt.Errorf("Unable to get the TempDir under %s: %s", config.Root, err)

 	}

@@ -924,12 +924,29 @@ func (daemon *Daemon) GetRemappedUIDGID() (int, int) {

 	return uid, gid

 }

-// tempDir returns the default directory to use for temporary files.

-func tempDir(rootDir string, rootUID, rootGID int) (string, error) {

+// prepareTempDir prepares and returns the default directory to use

+// for temporary files.

+// If it doesn't exist, it is created. If it exists, its content is removed.

+func prepareTempDir(rootDir string, rootUID, rootGID int) (string, error) {

 	var tmpDir string

 	if tmpDir = os.Getenv("DOCKER_TMPDIR"); tmpDir == "" {

 		tmpDir = filepath.Join(rootDir, "tmp")

+		newName := tmpDir + "-old"

+		if err := os.Rename(tmpDir, newName); err != nil {

+			go func() {

+				if err := os.RemoveAll(newName); err != nil {

+					logrus.Warnf("failed to delete old tmp directory: %s", newName)

+				}

+			}()

+		} else {

+			logrus.Warnf("failed to rename %s for background deletion: %s. Deleting synchronously", tmpDir, err)

+			if err := os.RemoveAll(tmpDir); err != nil {

+				logrus.Warnf("failed to delete old tmp directory: %s", tmpDir)

+			}

+		}

 	}

+	// We don't remove the content of tmpdir if it's not the default,

+	// it may hold things that do not belong to us.

 	return tmpDir, idtools.MkdirAllAs(tmpDir, 0700, rootUID, rootGID)

 }