Comment 15 for bug 1617299

Reviewed: https://review.openstack.org/382159
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=eeb23c78914891a5a6943c09c87aceb720d45f58
Submitter: Jenkins
Branch: stable/mitaka

commit eeb23c78914891a5a6943c09c87aceb720d45f58
Author: Tom Patzig <email address hidden>
Date: Wed Sep 7 11:16:49 2016 +0200

    refresh instances_path when shared storage used

    When doing Live migration with shared storage, it happens erratically,
    that the check for the shared storage test_file fails. Because the shared
    volume is under heavy IO (many instances on many compute nodes) the client
    does not immediately sees the new content of the folder. This delay
    could take up to 30s.
    This can be fixed if the client is forced to refresh the directories
    content, which can be achieved by 'touch' on the directory. Doing so,
    the test_file is visibile instantly, within ms.
    The patch adds a 'touch' on instances_path in check_shared_storage_test_file,
    before checking the existence of the file.

    Conflicts:
        nova/tests/unit/virt/libvirt/test_driver.py

    NOTE(lyarwood): Conflict caused by the signature of
    _check_shared_storage_test_file changing as part of I6cca257

    Change-Id: I16be39142278517f43e6eca3441a56cbc9561113
    Closes-Bug: #1617299
    (cherry picked from commit 1af73d1fb3169c5b3cce77d94316922496bbaf9a)