Linux bridge agent downs if vlan tag is already used

Linux bridge agent downs if vlan tag is already used
I'm not sure spec of the linux bridge agent. So may be this behavior is not bug.

Stderr: "device eth0.1000 is already a member of a bridge; can't enslave it to bridge brqdaffeb68-ab.\n"
Traceback (most recent call last):
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 751, in <module>
    main()
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 746, in main
    plugin.daemon_loop()
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 700, in daemon_loop
    sync = self.process_network_devices(device_info)
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 630, in process_network_devices
    resync_a = self.treat_devices_added(device_info['added'])
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 655, in treat_devices_added
    details['vlan_id'])
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 595, in process_port_binding
    interface_id)
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 290, in add_interface
    tap_device_name)
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 260, in add_tap_interface
    self.ensure_vlan_bridge(network_id, physical_interface, vlan_id)
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 179, in ensure_vlan_bridge
    self.ensure_bridge(bridge_name, interface)
  File "/opt/stack/quantum/quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py", line 230, in ensure_bridge
    root_helper=self.root_helper)
  File "/opt/stack/quantum/quantum/agent/linux/utils.py", line 55, in execute
    raise RuntimeError(m)
RuntimeError:
Command: ['sudo', 'brctl', 'addif', 'brqdaffeb68-ab', 'eth0.1000']
Exit code: 1
Stdout: ''
Stderr: "device eth0.1000 is already a member of a bridge; can't enslave it to bridge brqdaffeb68-ab.\n"
DEBUG:amqplib:Closed channel #1
2012-08-19 22:06:07 DEBUG [amqplib] Closed channel #1