[PATCH qemu-server v2 0/2] fix #6490: network: bridge fdb entries on nic hotplug

["Rémi PAETA" <remi.paeta@comaite.com>]

Thank you Gabriel and Fiona for your feedback on v1! This v2 takes it
into account.

On bridges with MAC learning disabled, hotplugged or re-plugged NICs
get no forwarding database entries, so the guest loses connectivity on
that NIC, and a later live migration fails when deleting the missing
entries.

v1: https://lore.proxmox.com/pve-devel/20261013095852.2586609-1-remi.paeta@comaite.com/

Changes since v1, following your feedback:
- new first patch: only warn when deleting the entries fails at the end
  of a migration, instead of failing the migration after the VM state
  was transferred
- only warn when adding the entries fails after plugging the NIC, so
  the configuration stays in sync with the running VM
- only add the entries on hotplug if the NIC has a bridge, to not warn
  about NICs without one

Note that with the synchronous config update of the web UI, such a
warning only ends up in the syslog, as there is no task log.

Tested on a Linux bridge with bridge-disable-mac-learning, with a
failure of 'bridge fdb' injected where noted:
- toggling the firewall of a NIC and hotplugging a NIC: entries added,
  connectivity kept
- same with an injected failure: warning, configuration updated (v1
  failed the update and left the new value pending, while the NIC was
  already re-plugged)
- live migration with missing entries: warnings, migration succeeds,
  entries re-added on the target on resume, no QEMU left on the source
  (without the first patch, the VM stayed paused and locked on the
  target)

Rémi PAETA (2):
  network: do not fail on missing bridge fdb entries when migrating
  fix #6490: network: add bridge fdb entries when hotplugging a nic

 src/PVE/QemuServer.pm         | 8 ++++++++
 src/PVE/QemuServer/Network.pm | 3 ++-
 2 files changed, 10 insertions(+), 1 deletion(-)

-- 
2.47.3