daemon: registerName(): don't reserve name twice

daemon.generateNewName() already reserves the generated name, but its name
did not indicate it did. The daemon.registerName() assumed that the generated
name still had to be reserved, which could mean it would try to reserve the
same name again.

This patch renames daemon.generateNewName to daemon.generateAndReserveName
to make it clearer what it does, and updates registerName() to return early
if it successfully generated (and registered) the container name.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

daemon/names.go

@@ -26,11 +26,12 @@ func (daemon *Daemon) registerName(container *container.Container) error {
 		return err
 	}
 	if container.Name == "" {
-		name, err := daemon.generateNewName(container.ID)
+		name, err := daemon.generateAndReserveName(container.ID)
 		if err != nil {
 			return err
 		}
 		container.Name = name
+		return nil
 	}
 	return daemon.containersReplica.ReserveName(container.Name, container.ID)
 }
@@ -42,7 +43,7 @@ func (daemon *Daemon) generateIDAndName(name string) (string, string, error) {
 	)
 
 	if name == "" {
-		if name, err = daemon.generateNewName(id); err != nil {
+		if name, err = daemon.generateAndReserveName(id); err != nil {
 			return "", "", err
 		}
 		return id, name, nil
@@ -81,7 +82,7 @@ func (daemon *Daemon) releaseName(name string) {
 	daemon.containersReplica.ReleaseName(name)
 }
 
-func (daemon *Daemon) generateNewName(id string) (string, error) {
+func (daemon *Daemon) generateAndReserveName(id string) (string, error) {
 	var name string
 	for i := 0; i < 6; i++ {
 		name = namesgenerator.GetRandomName(i)