Comment 8 for bug 1943714

Reviewed: https://review.opendev.org/c/openstack/neutron/+/809983
Committed: https://opendev.org/openstack/neutron/commit/603abeb977d4018963beade5c858b53f990ef32a
Submitter: "Zuul (22348)"
Branch: master

commit 603abeb977d4018963beade5c858b53f990ef32a
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Mon Sep 20 09:27:39 2021 +0000

    Execute the quota reservation removal in an isolated DB txn

    The goal of [1] is to, in case of failing when removing the quota
    reservation, continue the operation. Any expired reservation will
    be removed automatically in any driver.

    If the DB transaction fails, it should affect only to the reservation
    trying to be deleted. This is why this patch isolates the
    "remove_reservation" method and guarantees it is called outside an
    active DB session. That guarantees, in case of failure, no other DB
    operation will be affected.

    This patch also partially reverts [2] but still checks the security
    group rule quota when a new security group is created. Instead of
    creating and releasing a quota reservation for the security group
    rules created, now only the available quota limit is checked before
    creating them. That won't prevent another operation to create security
    group rules in parallel, exceeding the available quota. However, this
    is not even guaranteed with the current quota driver.

    [1]https://review.opendev.org/c/openstack/neutron/+/805031
    [2]https://review.opendev.org/c/openstack/neutron/+/701565

    Closes-Bug: #1943714

    Change-Id: Id73368576a948f78a043d7cf0be16661a65626a9