Comment 10 for bug 1737779

Reviewed: https://review.openstack.org/527468
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=16d0ad344e22aa5aa5d0c42a872f079587b62c6d
Submitter: Zuul
Branch: master

commit 16d0ad344e22aa5aa5d0c42a872f079587b62c6d
Author: Matt Riedemann <email address hidden>
Date: Tue Dec 12 12:09:50 2017 -0500

    Pass mountpoint to volume attachment_update

    The old volume attach flow would pass the mountpoint,
    which is the BlockDeviceMapping.device_name, to the
    os-attach volume action API. With the new flow, apparently
    the mountpoint is expected to be passed to the update
    attachment API via the connector dict, which is not obvious
    and if not provided, causes Cinder to default the mountpoint
    to "/dev/na" which is wrong.

    We work around this in Nova by providing the mountpoint in a
    copy of the connector dict and pass that to attachment_update,
    and update the two places in the code that are updating an
    attachment (the normal driver block device attach code and
    swap volume). Long-term this should be fixed in the Cinder
    attachments update API, but that requires a microversion so
    we need to handle it client-side for now.

    Change-Id: I11ba269c3f7a2e7707b2b7e27d26eb7a2c948a82
    Partial-Bug: #1737779