[PATCH v3 0/3] More graceful handling of migration without passt-repair

[David Gibson <david@gibson.dropbear.id.au>]

From Red Hat internal testing we've had some reports that if
attempting to migrate without passt-repair, the failure mode is uglier
than we'd like.  The migration fails, which is somewhat expected, but
we don't correctly roll things back on the source, so it breaks
network there as well.

Handle this more gracefully allowing the migration to proceed in this
case, but allow TCP connections to break

I've test patches 1..2/3 reasonably:
 * I get a clean migration if there are now active flows
 * Migration completes, although connections are broken if
   passt-repair isn't connected
 * Basic test suite (minus perf)

Patch 3 I've run the basic test suite on, but haven't tested the
specific functionality of.  Alas, I've spent most of today battling
with RHEL, virt-install, unshare and various other things trying to
create a test environment simulating two hosts with (possibly)
different addresses.  Despite the example given by Stefano in reply to
the previous version, I haven't really succeeded yet.

There are more fragile cases that I'm looking to fix, particularly the
die()s in flow_migrate_source_rollback() and elsewhere, however I ran
into various complications that I didn't manage to sort out today.
I'll continue looking at those tomorrow.

David Gibson (3):
  migrate, flow: Trivially succeed if migrating with no flows
  migrate, flow: Don't attempt to migrate TCP flows without passt-repair
  migrate, tcp: Don't attempt to carry on migration after
    flow_alloc_cancel()

 flow.c | 17 +++++++++++++++--
 tcp.c  |  5 ++++-
 2 files changed, 19 insertions(+), 3 deletions(-)

-- 
2.48.1