On Tue, Nov 17, 2020 at 02:29:27PM +0100, Michal Privoznik wrote: > On 11/17/20 1:51 PM, Daniel P. Berrangé wrote: > > On Tue, Nov 17, 2020 at 01:29:47PM +0100, Michal Privoznik wrote: > > > In v6.3.0-rc1~67 I've made a switch: instead of listening on udev > > > events the nodedev driver started listening for kernel events. > > > This was because when a device changes its name (e.g. NICs) we > > > will get "move" event with DEVPATH_OLD property set, which we can > > > then use to remove the old device and thus keep our internal list > > > up to date. The switch to "kernel" source was made because if the > > > old NICs naming (eth0, eth1, ...) is enabled (e.g. via > > > net.ifnames=0 on the kernel cmd line) then udev overwrites the > > > property with the new name making our internal list go out of > > > sync. Interestingly, when the od NICs naming is not enabled then > > > the DEVPATH_OLD contains the correct value. > > > > I don't see any difference in properties regardless of net.ifnames > > is 0 or 1. In both cases, there is DEVPATH + DEVPAT_OLD, and > > INTERFACE has the new NIC name. Can you actually reproduce the > > original problem with net.ifnames=0 ? If so, which distro ? > > Have you tried renaming back and forth? for instance: > > # ip link set tunl0 name tunl1 > # ip link set tunl1 name tunl0 > > > The "kernel" source yields: > > KERNEL[778387.296879] move /devices/virtual/net/tunl1 (net) > ACTION=move > DEVPATH=/devices/virtual/net/tunl1 > DEVPATH_OLD=/devices/virtual/net/tunl0 > IFINDEX=5 > INTERFACE=tunl1 > SEQNUM=20701 > SUBSYSTEM=net > > KERNEL[778400.944769] move /devices/virtual/net/tunl0 (net) > ACTION=move > DEVPATH=/devices/virtual/net/tunl0 > DEVPATH_OLD=/devices/virtual/net/tunl1 > IFINDEX=5 > INTERFACE=tunl0 > SEQNUM=20702 > SUBSYSTEM=net > > > But "udev" gets: > > UDEV [778387.297247] move /devices/virtual/net/tunl1 (net) > ACTION=move > DEVPATH=/devices/virtual/net/tunl1 > DEVPATH_OLD=/devices/virtual/net/tunl0 > IFINDEX=5 > INTERFACE=tunl1 > SEQNUM=20701 > SUBSYSTEM=net > USEC_INITIALIZED=5901449841 > net.ifnames=0 > > UDEV [778400.945195] move /devices/virtual/net/tunl1 (net) > ACTION=move > DEVPATH=/devices/virtual/net/tunl1 > DEVPATH_OLD=/devices/virtual/net/tunl1 > IFINDEX=5 > INTERFACE=tunl1 > SEQNUM=20702 > SUBSYSTEM=net > USEC_INITIALIZED=5901449841 > net.ifnames=0 > > > In both cases the first rename (tunl0 -> tunl1) gets correct DEVPATH_OLD, > but the second rename is problematic (tunl1 -> tunl0) and only "kernel" gets > it right. Hmm, this simply smells like a bug we should report to udev. It makes no sense that the event is correct for the first rename, and then wrong for the subsequent rename. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
