Stephen Hemminger <step...@networkplumber.org> writes: > On Tue, 08 Aug 2017 17:24:03 +0200 > Vitaly Kuznetsov <vkuzn...@redhat.com> wrote: > >> Stephen Hemminger <step...@networkplumber.org> writes: >> >> > On Tue, 08 Aug 2017 16:03:56 +0200 >> > Vitaly Kuznetsov <vkuzn...@redhat.com> wrote: >> > >> >> Stephen Hemminger <step...@networkplumber.org> writes: >> >> >> >> > Previous fix was incomplete. >> >> > >> >> >> >> Not really related to this patch series (which btw fixes my issue, >> >> thanks!), but I found one addition issue. Systemd fails to rename VF >> >> interface: >> >> >> >> kernel: mlx4_core 0002:00:02.0 eth2: joined to eth1 >> >> kernel: hv_netvsc 33b7a6f9-6736-451f-8fce-b382eaa50bee eth1: VF >> >> registering: eth2 >> >> kernel: hv_netvsc 33b7a6f9-6736-451f-8fce-b382eaa50bee eth1: Data path >> >> switched to VF: eth2 >> >> kernel: mlx4_en: eth2: Link Up >> >> NetworkManager[750]: <info> [1502200557.0821] device (eth2): link >> >> connected >> >> NetworkManager[750]: <info> [1502200557.1004] manager: (eth2): new >> >> Ethernet device (/org/freedesktop/NetworkManager/Devices/6) >> >> systemd-udevd[6942]: Error changing net interface name 'eth2' to >> >> 'enP2p0s2': Device or resource busy >> >> systemd-udevd[6942]: could not rename interface '6' from 'eth2' to >> >> 'enP2p0s2': Device or resource busy >> >> >> >> With some debug added I figured out what's wrong: __netvsc_vf_setup() >> >> does dev_open() which sets IFF_UP flag on the interface. When systemd >> >> tries to rename the interface we get into dev_change_name() and this >> >> fails with -EBUSY when (dev->flags & IFF_UP). >> >> >> >> The issue is of less importance as we're not supposed to configure VF >> >> interface now. However, we may still want to get a stable name for it. >> >> >> >> Any idea how this can be fixed? >> > >> > The problem is Network Manager should ignore the VF device. I don't run NM >> > on these >> > interfaces because it causes more issues than it helps (dueling userspace). >> > >> > The driver needs to have slave track the master interface. Relying on >> > userspace >> > to bring interface up leads to all the issues the bonding script had. >> > >> > One option would be to delay the work of bringing up the slave device to >> > allow >> > small window for renaming to run. >> >> Actually, I tried removing 'if (dev->flags & IFF_UP)' check from >> dev_change_name() and everything seems to work fine. The history of this >> code predates git so I have no idea why it's forbiden to change names of >> IFF_UP interfaces... I can send an RFC removing the check to figure out >> the truth :-) > > That only works because NM by default brings everything up. > Many users don't use NM on servers.
I'm not sure NetworkManager is related here: renaming is done by systemd/udev according to the "predictable interface names" scheme: https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ Basically, systemd/udev tries to rename all new interfaces in the system according to this scheme. And systemd/udev is ubiquitous nowdays. I tried disabling NetworkManager in my VM and the behavior is not any different: kernel: mlx4_core 0002:00:02.0 eth2: joined to eth1 kernel: hv_netvsc 33b7a6f9-6736-451f-8fce-b382eaa50bee eth1: VF registering: eth2 kernel: mlx4_en: eth2: Link Up kernel: hv_netvsc 33b7a6f9-6736-451f-8fce-b382eaa50bee eth1: Data path switched to VF: eth2 systemd-udevd[1785]: Error changing net interface name 'eth2' to 'enP2p0s2': Device or resource busy systemd-udevd[1785]: could not rename interface '5' from 'eth2' to 'enP2p0s2': Device or resource busy The 'if (dev->flags & IFF_UP)' check in dev_change_name() function I mentioned prevents renaming interfaces which are already up but I don't know an obvious reason for it to exist. -- Vitaly
