powervm error'd local volume cleanup fails

[Mathew Odden]

During spawn, if a local volume for the backing block device fails to be created, the cleanup operation for the volume can fail with a "UnboundLocalError: local variable 'disk_name' referenced before assignment" error.

The fix is to assign to disk_name earlier and check for None before running cleanup.

Logs:

2013-05-16 13:40:34.521 ERROR nova.virt.powervm.blockdev [req-5bf9faeb-d14e-45d9-afc5-6c9e90e82257 4e06f68d356744f1a4e832e3c154c1d9 b3b27607effe4cc6a284ae4278d67a2a] Could not create logical volume. No space left on any volume group.
2013-05-16 13:40:34.522 ERROR nova.virt.powervm.blockdev [req-5bf9faeb-d14e-45d9-afc5-6c9e90e82257 4e06f68d356744f1a4e832e3c154c1d9 b3b27607effe4cc6a284ae4278d67a2a] Error while creating logical volume from image. Will attempt cleanup.
2013-05-16 13:40:34.523 ERROR nova.virt.powervm.blockdev [req-5bf9faeb-d14e-45d9-afc5-6c9e90e82257 4e06f68d356744f1a4e832e3c154c1d9 b3b27607effe4cc6a284ae4278d67a2a] Error while attempting cleanup of failed deploy to logical volume.
2013-05-16 13:40:34.523 18061 TRACE nova.virt.powervm.blockdev Traceback (most recent call last):
2013-05-16 13:40:34.523 18061 TRACE nova.virt.powervm.blockdev File "/usr/lib/python2.6/site-packages/nova/virt/powervm/blockdev.py", line 309, in create_volume_from_image
2013-05-16 13:40:34.523 18061 TRACE nova.virt.powervm.blockdev self.delete_volume(disk_name)
2013-05-16 13:40:34.523 18061 TRACE nova.virt.powervm.blockdev UnboundLocalError: local variable 'disk_name' referenced before assignment
2013-05-16 13:40:34.523 18061 TRACE nova.virt.powervm.blockdev
2013-05-16 13:40:34.525 ERROR nova.virt.powervm.operator [req-5bf9faeb-d14e-45d9-afc5-6c9e90e82257 4e06f68d356744f1a4e832e3c154c1d9 b3b27607effe4cc6a284ae4278d67a2a] PowerVM image creation failed: No space left on any volume group
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator Traceback (most recent call last):
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator File "/usr/lib/python2.6/site-packages/nova/virt/powervm/operator.py", line 345, in _create_image
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator context, instance, image_id)
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator File "/usr/lib/python2.6/site-packages/nova/virt/powervm/blockdev.py", line 313, in create_volume_from_image
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator LOG.exception(msg)
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator File "/usr/lib64/python2.6/contextlib.py", line 23, in __exit__
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator self.gen.next()
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator File "/usr/lib/python2.6/site-packages/nova/virt/powervm/blockdev.py", line 299, in create_volume_from_image
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator disk_name = self._create_logical_volume(size)
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator File "/usr/lib/python2.6/site-packages/nova/virt/powervm/blockdev.py", line 450, in _create_logical_volume
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator raise exception.PowerVMNoSpaceLeftOnVolumeGroup()
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator PowerVMNoSpaceLeftOnVolumeGroup: No space left on any volume group
2013-05-16 13:40:34.525 18061 TRACE nova.virt.powervm.operator

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/29991

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/29991
Committed: http://github.com/openstack/nova/commit/6ea7df2cbcdca6c9be0c44d2436e24549c499297
Submitter: Jenkins
Branch: master

commit 6ea7df2cbcdca6c9be0c44d2436e24549c499297
Author: Matt Riedemann <email address hidden>
Date: Tue May 21 13:33:19 2013 -0700

    Fix UnboundLocalError in powervm lvm cleanup code

    During spawn, if a local volume for the backing block device fails to
    be created, the cleanup operation for the volume can fail with a
    "UnboundLocalError: local variable 'disk_name' referenced before
    assignment" error.

    The fix is to assign to disk_name earlier and check for None before
    running cleanup.

    This patch also adds tests to cover the failure case.

    Fixes bug 1180955

    Change-Id: I0f32df1586d7bd87eccb674fec2a9597b1ce351d