Re: [PATCH] node_device: Use "udev" monitor source
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.
This is on 5.9.1-gentoo-x86_64 and
# udevadm --version
243
>
> But as it turns out, "kernel" source might be missing some other
> important properties, e.g. USB vendor/product IDs. Therefore,
> switch back to "udev" source and wish the best of luck to users
> using the old NICs naming.
>
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1897625
> Fixes: 9a13704818e4a018723e0ec5b9e97b176f1c8584
> Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
> ---
> src/node_device/node_device_udev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/node_device/node_device_udev.c b/src/node_device/node_device_udev.c
> index 65f312d8f4..dec19a3166 100644
> --- a/src/node_device/node_device_udev.c
> +++ b/src/node_device/node_device_udev.c
> @@ -1983,7 +1983,7 @@ nodeStateInitialize(bool privileged,
>
> virObjectLock(priv);
>
> - priv->udev_monitor = udev_monitor_new_from_netlink(udev,
"kernel");
> + priv->udev_monitor = udev_monitor_new_from_netlink(udev, "udev");
> if (!priv->udev_monitor) {
> virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> _("udev_monitor_new_from_netlink returned
NULL"));
Reviewed-by: Daniel P. Berrangé <berrange(a)redhat.com>
Pushed. Thanks.
Michal