Bug#856558: udev-generated /dev/disk/by-path names broken for virtio disks

[Viktor Mihajlovski]

Source: systemd
Version: 232
Severity: normal
Tags: upstream patch
X-Debbugs-CC: debian-s390 at lists.debian.org

Dear Maintainer,

in Linux running as a KVM guest, virtio disks show up in the following
format in the /dev/disk/by-path directory:
 virtio-pci-<systemid> (on x86, s390 and armv7l)

This format implies that the device is a virtio-pci device, however this
is only true for x86. On s390 it's virtio-ccw and on arm it's typically
virtio-mmio.

The upstream commit at [1] fixes this by generating a uniform path id in
the format
 <subsystem>-<systemid>
This will typically be something like
 pci-0000:00:00:7.0 (for x86)
 ccw-0.0.1234 (for s390)
 platform-a003e00.virtio_mmio (for arm)

On x86 additional symlinks are created for backward compatibility, i.e.
 virtio-pci-0000:00:00:7.0

This patch is only needed for systemd 229 or higher.

[1]
https://github.com/systemd/systemd/commit/fb92fbb1b171ef94207a1ebc111ef0e414d49b4

Thanks!