The lookup cache wrote an entry even when the plugin returned nothing, and that entry short-circuits every later lookup, so a record created after the first miss was never seen again. The read-modify-write also ran without the cluster lock the other cache writers take, allowing concurrent lookups to drop each other's entries.
Only cache actual answers and take the lock for the write, keeping the common cache-hit path lock-free. Signed-off-by: Hannes Laimer <[email protected]> --- src/PVE/Network/SDN/Ipams.pm | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/src/PVE/Network/SDN/Ipams.pm b/src/PVE/Network/SDN/Ipams.pm index 179bdf7..9292386 100644 --- a/src/PVE/Network/SDN/Ipams.pm +++ b/src/PVE/Network/SDN/Ipams.pm @@ -140,12 +140,24 @@ sub get_ips_from_mac { my $plugin_config = get_plugin_config($zone); my $plugin = PVE::Network::SDN::Ipams::Plugin->lookup($plugin_config->{type}); - ($macdb->{macs}->{$mac}->{ip4}, $macdb->{macs}->{$mac}->{ip6}) = - $plugin->get_ips_from_mac($plugin_config, $mac, $zoneid); + my ($ip4, $ip6) = $plugin->get_ips_from_mac($plugin_config, $mac, $zoneid); - write_macdb($macdb); + # an empty answer is not cached, the record may simply not exist yet + return if !defined($ip4) && !defined($ip6); - return ($macdb->{macs}->{$mac}->{ip4}, $macdb->{macs}->{$mac}->{ip6}); + cfs_lock_file( + $macdb_filename, + undef, + sub { + my $db = read_macdb(); + $db->{macs}->{$mac}->{ip4} = $ip4 if defined($ip4); + $db->{macs}->{$mac}->{ip6} = $ip6 if defined($ip6); + write_macdb($db); + }, + ); + warn "$@" if $@; + + return ($ip4, $ip6); } 1; -- 2.47.3
