(s)ata disks do not have /dev/disk/by-path links created

[Dan Streetman]

[impact]

udev (in trusty) does not create symlinks in /dev/disk/by-path/ for any disks that are connected via sata.

[test case]

Install trusty onto a system with sata drives, and check /dev/disk/by-path/ for symlink(s) to those sata drive(s).

[regression potential]

the (s)ata by-path symlinks were removed due to apparent possibility of non-uniqueness:
https://git.kernel.org/pub/scm/linux/hotplug/udev.git/commit/?id=481dcf7c8f

however that was *long* ago and it has been added back in:
https://github.com/systemd/systemd/commit/ba86822db70d9ffd02ad78cd02b237ff8c569c7a

if there is still a possibility for non-uniqueness, then /dev/disk/by-path/ symlink(s) might be created that are non-deterministic as far as the actual disk/path they point to.

[other info]

this is 'fixed' (the by-path symlinks are created for ata disks) in Xenial and later systemd/udev.

Also bug 1611945 indicates that sata devices connected via PMP (port multiplier device) may still have incorrect by-path symlinks created, even upstream. However, since Xenial and later currently do have udev code that creates ata by-path symlinks, that is a separate issue and not a reason for keeping ata by-path symlinks about of trusty udev.

[Brian Murray (brian-murray)]

Hello Dan, or anyone else affected,

Accepted systemd into trusty-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/systemd/204-5ubuntu20.29 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-trusty to verification-done-trusty. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-trusty. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Dan Streetman (ddstreet)]

ubuntu@dwalin:~$ dpkg -l | grep ' udev '
ii udev 204-5ubuntu20.28 amd64 /dev/ and hotplug management daemon
ubuntu@dwalin:~$ ls -l /dev/disk/by-path/
ls: cannot access /dev/disk/by-path/: No such file or directory

ubuntu@dwalin:~$ dpkg -l | grep ' udev '
ii udev 204-5ubuntu20.29 amd64 /dev/ and hotplug management daemon
ubuntu@dwalin:~$ ls -l /dev/disk/by-path/
total 0
lrwxrwxrwx 1 root root 9 Nov 29 21:43 pci-0000:00:1f.2-ata-1 -> ../../sda
lrwxrwxrwx 1 root root 10 Nov 29 21:43 pci-0000:00:1f.2-ata-1-part1 -> ../../sda1

[Dan Streetman (ddstreet)]

the linux-* autopkgtest failures are known and expected (bug 1723223) and can be ignored.