unshelve failed when instance attached volume

unshelved instance failed when the instance attached one volume.

reproduce:
1. instance boot from image;
2. create 1GB volume in lvm, use local storage;
3. attach volume to instance;
4. shelve instance, then unshelve instance

detail logs:
2014-12-30 08:43:17.401 8797 ERROR nova.compute.manager [req-df836400-b68f-4a0b-89a1-055dcad00b70 40dc8656066f432895be13be71e44b86 a20fb3edeab44755a861f510183a679a] [instance: 1632aa3b-5a00-495a-9041-283566592a65] Instance failed block device setup
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] Traceback (most recent call last):
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 1890, in _prep_block_device
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] self.driver, self._await_block_device_map_created) +
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] File "/usr/lib/python2.7/site-packages/nova/virt/block_device.py", line 367, in attach_block_devices
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] map(_log_and_attach, block_device_mapping)
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] File "/usr/lib/python2.7/site-packages/nova/virt/block_device.py", line 365, in _log_and_attach
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] bdm.attach(*attach_args, **attach_kwargs)
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] File "/usr/lib/python2.7/site-packages/nova/virt/block_device.py", line 44, in wrapped
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] ret_val = method(obj, context, *args, **kwargs) 2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] File "/usr/lib/python2.7/site-packages/nova/virt/block_device.py", line 217, in attach
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] volume_api.check_attach(context, volume, instance=instance)
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] File "/usr/lib/python2.7/site-packages/nova/volume/cinder.py", line 234, in check_attach
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] raise exception.InvalidVolume(reason=msg)
2014-12-30 08:43:17.401 8797 TRACE nova.compute.manager [instance: 1632aa3b-5a00-495a-9041-283566592a65] InvalidVolume: Invalid volume: Volume has been attached to the instance