Comment 9 for bug 1221525

Reviewed: https://review.openstack.org/92866
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=ea91ad2b2317cb88fb14c0cdaf31187eca93ff57
Submitter: Jenkins
Branch: master

commit ea91ad2b2317cb88fb14c0cdaf31187eca93ff57
Author: Lucian Petrut <email address hidden>
Date: Thu May 8 18:46:22 2014 +0300

    Fixes Hyper-V iSCSI target login method

    Hyper-V is trying to log in to portals/targets every time a volume
    is attached, even if the portal/target was already connected. This
    is not an issue with most volume backends, but it causes the attach
    to fail when using Storwize as a Cinder backend.

    This patch fixes the issue by checking if the target or portal is
    already connected, and simply perform an update in this case,
    instead of attempting to create a new connection.

    Also, a retry loop is introduced for the case when the iSCSI target
    login fails. As in this loop it is checked whether or not the
    operation completed successfully, this method does not rely anymore
    only on a sleep interval to ensure that the connection to the target
    has been made. Even so, on V2 volume utilities, the sleep interval
    is still needed to avoid having a new connection attempt before the
    last one finished.

    The method which gets the according mounted disk must raise an
    exception when the device number is -1, which signifies that the
    disk has not been mounted properly.

    Co-Authored-By: Jay Bryant <email address hidden>

    Closes-bug: #1221525

    Change-Id: I92d2a586704fa3e857f46432bb571c81e86d183b