Comment 29 for bug 1382440

Reviewed: https://review.openstack.org/188159
Committed: https://git.openstack.org/cgit/openstack/os-brick/commit/?id=a8386d5cbe732a4e3f4daf836a6efdf69ee6e11f
Submitter: Jenkins
Branch: master

commit a8386d5cbe732a4e3f4daf836a6efdf69ee6e11f
Author: Tomoki Sekiyama <email address hidden>
Date: Wed Jun 3 13:42:34 2015 -0400

    Fix connecting unnecessary iSCSI sessions issue

    With "iscsi_use_multipath=true", attaching a multipath
    iSCSI volume may create unnecessary iSCSI sessions.
    The iscsiadm discovery command in connect_volume() returns all of
    the targets in the Cinder node, not just the ones related to
    the multipath volume which is specified by iqn. If the storage
    has many targets, connecting to all these volumes will also
    result in many unnecessary connections.

    There are two types of iSCSI multipath devices.
    One which shares the same iqn between multiple portals,
    and the other which use different iqns on different portals.
    connect_volume() needs to identify the type by checking iscsiadm
    the output if the iqn is used by multiple portals.

    This patch changes the behavior of attaching volume:

       1. Identify the type by checking the iscsiadm output.
       2. Connect to the correct targets by connect_to_iscsi_portal().

    (Ported from I488ad0c09bf26a609e27d67b9ef60b65bb45e0ad)

    Co-Authored-By: Hiroyuki Eguchi <email address hidden>
    Related-Bug: #1382440
    Change-Id: I4c9b173cfab387a55772709242eed69c10168c0f