Comment 8 for bug 1566815

Reviewed: https://review.openstack.org/350647
Committed: https://git.openstack.org/cgit/openstack/manila/commit/?id=d878826cf3524e9e2f1d972072c7844934509616
Submitter: Jenkins
Branch: master

commit d878826cf3524e9e2f1d972072c7844934509616
Author: Valeriy Ponomaryov <email address hidden>
Date: Tue Aug 2 20:27:46 2016 +0300

    Fix concurrent usage of update_access method for share instances

    In mitaka, update_access merged with a known concurrency issue.
    This concurrency has been randomly failing in our CIs. This change
    adds a lock mechanism to prevent that, while rules are being removed
    by a thread, a parallel thread adds back or handle the same rules
    that are being removed.

    Also, a late mitaka update_access patch [1] broke share migration access
    rules consistency, thus leaving stale access rule data on share server
    that hosted the share prior to its migration. This patch addresses this
    by preventing the refresh mechanism from adding back rules
    that are removed.

    [1] I0f863cbae4d8af0660114161deda7bf7aa60d71d

    Change-Id: Ief3b15eefc0fc325a2a5418fc7ac2724c315cc21
    Co-Authored-By: Rodrigo Barbieri <email address hidden>
    Co-Authored-By: Goutham Pacha Ravi <email address hidden>
    Closes-Bug: #1566815
    Closes-Bug: #1609414