LVM backed images unnecessarily mounted to block devices

[Andrew Melton]

When using the libvirt drivers support for LVM backed images, the the LVM device is mounted to either a loopback or nbd device before finally being mounted to the rootfs directory for the instance. This is unnecessary because the image is already exposed as a block drive by LVM/device mapper. Thus, the LVM device can be mounted directly to the rootfs of the instance.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/130163

[OpenStack Infra (hudson-openstack)]

Change abandoned by Andrew Melton (<email address hidden>) on branch: master
Review: https://review.openstack.org/106405

[OpenStack Infra (hudson-openstack)]

Change abandoned by Rick Harris (<email address hidden>) on branch: master
Review: https://review.openstack.org/130163

[Davanum Srinivas (DIMS) (dims-v)]

All 3 reviews are abandoned, removing "In Progress" and assignee

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/215311

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/215310
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=faeae32a7e5b2048aacb05995b294e9665d78b8e
Submitter: Jenkins
Branch: master

commit faeae32a7e5b2048aacb05995b294e9665d78b8e
Author: Andrew Melton <email address hidden>
Date: Thu Aug 20 11:18:33 2015 -0700

    libvirt: refactor _create_domain_setup_lxc to use Image.get_model

    Instead of trying to figure out what the proper ImageModel is for
    the instance's image, just use the get_model function. The resulting
    ImageModel will actually represent the proper ImageModel for the
    instance, and downstream mounting functions will be able to make
    intelligent decisions on how to mount the instance's disks.

    It is not possible to use get_model for an instance booted from volume,
    but we can still use LocalBlockImage in it's case because it is
    simply exposed as a block device.

    Partial-Bug: #1287754
    Change-Id: I0f4456731c9d6f64affbf6924f4a7a4c34df4fd1

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/215311
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=0e16afa588954d494165368a9eb331421c0bdcd6
Submitter: Jenkins
Branch: master

commit 0e16afa588954d494165368a9eb331421c0bdcd6
Author: Andrew Melton <email address hidden>
Date: Thu Aug 20 12:50:13 2015 -0700

    virt: allow for direct mounting of LocalBlockImages

    Block backed images, are already presented as block devices, so
    LocalBlockImages can be mounted directly instead of being linked
    with loopback or nbd to another block device.

    Change-Id: I5aae1e293832f7cff7bc00d793bcc86ededf5eec
    Closes-bug: #1287754