Hi, with systemd > v229 all virtio block devices will receive persistent device names in the format /dev/disk-by/virtio-pci-<busid>, the last component being the udev built-in path_id. This naming introduces some issues. First and obvious, there are virtio implementations not based on PCI, like virtio-ccw (currently only on s390) and virtio-mmio (for which I can't speak). This results in persistent names like /dev/disk-by/virtio-pci-0.0.0001, where the bus id is a CCW id. One seemingly obvious remedy would be to make the path_id return virtio-ccw-<busid> or more generally virtio-<subsystem>-<busid>, both easily done with small patches to systemd-udev. But then, I find this naming scheme somewhat weird. A virtio disk shows up as a regular PCI function on the PCI bus side by side with other (non-virtio) devices. The naming otoh suggests that virtio-pci is a subsystem of its own, which is simply incorrect from a by-path perspective. Using just the plain PCI path id is actually sufficient to identify a virtio disk by its path. This would be in line with virtio network interface path names which use the plain PCI naming. One could argue about back-level compatibility, but virtio by-path naming has changed multiple times. We have seen virtio-pci-virtio<n> (not predictable), pci-<busid> and virtio-pci-<busid> already. It might be a good time now to settle on a common approach for all virtio types. For the reasons above, I'd vote for <subsystem>-<busid>, which would work for PCI and CCW, not sure about ARM MMIO though. Opinions? -- Mit freundlichen Grüßen/Kind Regards Viktor Mihajlovski IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martina Köderitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
