Comment 6 for bug 1697422

Reviewed: https://review.opendev.org/736302
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=408531cf2b0ae6bd5771046bd0f73cb795c7d9d4
Submitter: Zuul
Branch: stable/ussuri

commit 408531cf2b0ae6bd5771046bd0f73cb795c7d9d4
Author: Gorka Eguileor <email address hidden>
Date: Tue May 19 14:01:13 2020 +0200

    3PAR: Fix live migration

    After live migrating a volume into the 3PAR driver the volume would be
    unusable. And we would no longer be able to do any operation with it.

    Migrated in-use volumes cannot be renamed when migrated and therefore
    need to use the "_name_id" field of the Volume object (volumes table in
    the DB) to store the original volume's ID so the driver can locate the
    volume.

    The problem is that, even though the 3PAR driver sets the "_name_id"
    field, it doesn't use it for any operation, so once the volume has been
    migrated and the ID of the volume no longer matches the one that was
    used to create the volume (value now in "_name_id") it will no longer be
    able to locate the volume.

    This patch adds the logic necessary to locate volumes using the
    "_name_id" field.

    Closes-Bug: #1697422
    Change-Id: I27b9d4be419e1b52db02d4525b292ceeb5d5f867
    (cherry picked from commit fc51678298a38dcd94bcfe92c590b38fdb7193e4)