Comment 2 for bug 1581230

Reviewed: https://review.openstack.org/315789
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=2e9959878bd7f2cc1f42c2b823aaff0163ef398c
Submitter: Jenkins
Branch: master

commit 2e9959878bd7f2cc1f42c2b823aaff0163ef398c
Author: Walter A. Boring IV <email address hidden>
Date: Thu May 12 14:59:29 2016 -0700

    Don't check cinder volume states during attach

    This patch changes how Nova interacts with volumes at attach time.
    Nova should rely upon Cinder's os-reserve to determine if the
    state of the volume is in a good/valid state for attaching.
    This fixes a race between when nova fetches the volume and calls
    os-reserve.

    This refactors the volume_api.check_attach a bit and adds a new
    check_availability_zone, which is still done on the Nova side.
    When Cinder's os-reserve supports passing in the availability
    zone, then this check can also be removed.

    This patch handles the volume attach API, which is not checked
    again in the compute manager. Future patches will handle other
    operations like boot from volume and swap volume.

    Partial-Bug: #1581230

    Change-Id: I5b069ba3480257c061541fc6c19e044c31417b5e