ML2 delete_network can loop infinitely if called in transaction

Fix proposed to branch: master
Review: https://review.openstack.org/286843

Fix proposed to branch: master
Review: https://review.openstack.org/286920

You're welcome.

Reviewed: https://review.openstack.org/286920
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=d1c501cd1d31ed3f859975b40c01cb7aaa06d26d
Submitter: Jenkins
Branch: master

commit d1c501cd1d31ed3f859975b40c01cb7aaa06d26d
Author: Kevin Benton <email address hidden>
Date: Tue Mar 1 13:49:48 2016 -0800

    L3HA: Do not wrap create/delete in transaction

    This is unsafe when calling ML2 because ML2 assumes that its
    functions will not be called inside of a transaction. This is
    not only an issue for drivers that try to do DB lookups using
    a different session in the post commit operation, but it's a
    big issue for the delete methods.

    The delete subnet and network methods in ML2 have 'while True'
    loops that catch concurrency errors and retry the operation after
    looking up info. If these are called inside a transaction, the
    lookups will contain stale information and it can lead to the
    while True loop never terminating!

    Closes-Bug: #1551958
    Change-Id: I33dc084ed15e5491fdda19da712a746ca87fbc8c

Reviewed: https://review.openstack.org/286843
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=afe1a834000d33900b8646d308fa26fa807a2ca0
Submitter: Jenkins
Branch: master

commit afe1a834000d33900b8646d308fa26fa807a2ca0
Author: Kevin Benton <email address hidden>
Date: Tue Mar 1 10:47:00 2016 -0800

    Block delete_(network|subnet) transactioned calls

    These functions assume that they won't be called inside of a
    transaction for two reasons. The first is an infinite loop that
    will only terminate if it can actually retrieve the latest
    information from the database. The second is that ML2's post-commit
    operations are expected to occur after data was actually committed
    so mechanism drivers that do DB lookups using a different session
    may break.

    This adds an explicit guard that prevents these two functions from
    being called within an active DB session. The rest of the ML2
    functions should eventually be converted to this style as well
    (see the partial bug).

    Related-Bug: #1551958
    Partial-Bug: #1540844
    Change-Id: I5c00b186585369ef6c8e2b9cb5a43b8bba0e5a7c

This issue was fixed in the openstack/neutron 8.0.0.0rc1 release candidate.

Related fix proposed to branch: stable/liberty
Review: https://review.openstack.org/314022

Change abandoned by John Schwarz (<email address hidden>) on branch: stable/liberty
Review: https://review.openstack.org/314022

Fix proposed to branch: stable/liberty
Review: https://review.openstack.org/321633

Reviewed: https://review.openstack.org/321633
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=7130d4c5013e6cc37f3b0861424c7766ad5a66a4
Submitter: Jenkins
Branch: stable/liberty

commit 7130d4c5013e6cc37f3b0861424c7766ad5a66a4
Author: Kevin Benton <email address hidden>
Date: Tue Mar 1 13:49:48 2016 -0800

    L3HA: Do not wrap create/delete in transaction

    This is unsafe when calling ML2 because ML2 assumes that its
    functions will not be called inside of a transaction. This is
    not only an issue for drivers that try to do DB lookups using
    a different session in the post commit operation, but it's a
    big issue for the delete methods.

    The delete subnet and network methods in ML2 have 'while True'
    loops that catch concurrency errors and retry the operation after
    looking up info. If these are called inside a transaction, the
    lookups will contain stale information and it can lead to the
    while True loop never terminating!

    Conflicts:
     doc/source/devref/effective_neutron.rst
     neutron/db/l3_hamode_db.py

    Closes-Bug: #1551958
    Change-Id: I33dc084ed15e5491fdda19da712a746ca87fbc8c
    (cherry picked from commit d1c501cd1d31ed3f859975b40c01cb7aaa06d26d)

This issue was fixed in the openstack/neutron 7.1.2 release.