[LVMiSCSI] A volume is deleted unexpectedly during volume migration when src and dst VG names are same

[Mitsuhiro Tanino]

When using LVMISCSIDriver, a volume is unexpectedly deleted during volume migration operation.
This problem only occurs when the volume_group of backend A and backend B is same value by misconfiguration.
Even if the configuration is wrong, cinder should not delete the volume unexpectedly for user.

----- cinder.conf
enabled_backends=LVM_iscsi_drv,LVM_iscsi_drv2

[LVM_iscsi_drv]
volume_group=stack-volumes
volume_driver=cinder.volume.drivers.lvm.LVMISCSIDriver
volume_backend_name=LVM_iscsi

[LVM_iscsi_drv2]
volume_group=stack-volumes
volume_driver=cinder.volume.drivers.lvm.LVMISCSIDriver
volume_backend_name=LVM_iscsi
-----

Recreation Steps
(1) Configure multiple LVMiSCSI backend using same VG
(2) Create a new volume
(3) Migrate the volume to other backend

Logs
$ cinder-manage host list
control.com nova
control.com@LVM_iscsi_drv2 nova
control.com@LVM_iscsi_drv nova
$ sudo lvs
$ cinder create --name iscsi1 --volume-type LVM_iscsi 1
....
$ cinder list
+--------------------------------------+-----------+--------+------+-------------+----------+-------------+
| ID | Status | Name | Size | Volume Type | Bootable | Attached to |
+--------------------------------------+-----------+--------+------+-------------+----------+-------------+
| a57240ea-c06a-4a22-95f7-090fa88a6b42 | available | iscsi1 | 1 | LVM_iscsi | false | |
+--------------------------------------+-----------+--------+------+-------------+----------+-------------+
$ sudo lvs
  LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
  volume-a57240ea-c06a-4a22-95f7-090fa88a6b42 stack-volumes -wi-a----- 1.00g
$ cinder migrate a57240ea-c06a-4a22-95f7-090fa88a6b42 control.com@LVM_iscsi_drv2#LVM_iscsi
$ sudo lvs
$ sudo lvs

Whole c-vol log is here.
http://paste.openstack.org/show/152875/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/142922

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/142922
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=37e35047062b66321f9af6393b2b1c609af54e1a
Submitter: Jenkins
Branch: master

commit 37e35047062b66321f9af6393b2b1c609af54e1a
Author: Mitsuhiro Tanino <email address hidden>
Date: Thu Dec 18 09:07:24 2014 -0500

    LVM: Volume is deleted unexpectedly during volume migration

    When using LVMISCSIDriver, a volume is unexpectedly deleted during
    volume migration operation. This problem only occurs when the
    volume_group of backend A and backend B is same value such as
    misconfiguration. Even if the configuration is wrong, cinder should
    not delete the volume unexpectedly for user.

    Closes-Bug: 1404013
    Change-Id: I010be0c70589459a488cdef7cd83380eab27c61c