About blkid fix: Ryan has explained carefully how to obtain FS UUID from the backing device at:
https://github.com/systemd/systemd/pull/16317#issuecomment-655574875 and about bcache-export-cached wrapper he created for simulating CACHED_UUID and CACHED_LABEL (at 69-bcache.rules) and to create /dev/bcache/{by-uuid,by-label}/{CACHED_UUID,CACHED_LABEL} symlinks. He explained that having /dev/bcache/{by-uuid,by-label} is mandatory to maintain same names for multiple bcache'd environments over reboots. Currently, with the bcache-export-cached fix applied, it is *not* mandatory to have systemd-udev fix to correctly create bcache symlinks (or not) at /dev/disk/{by-uuid,by-label}: libblkid could have more information regarding bcache backing devices, but judging by upstream developers disposition they don't seem too worried about having that feature since ID_FS_TYPE=bcache is already provided. (So, having /dev/disk/by-uuid/XXX pointing to bcache backing devices would continue happening...) Summary: Having the bcache-tools fix is enough for this bug (LP: #1861941) and there could be changes to systemd-udev (I doubt judging by discussions at https://github.com/systemd/systemd/pull/16317), or libblkid, that could provide more information regarding bcache device types. If those changes happen, we would need to revisit this bug. IMHO, I like the "skip_bcache_fs_type" approach done by Ryan to systemd-udev. I'll maintain that as a delta to udev until https://github.com/systemd/systemd/pull/16317 is fixed (if ever). So, for now, PPA contains fix for bcache-tools for Groovy and Focal (and will for Bionic) and that is enough to make /dev/bcache/XXX to work and be stable after reboots. I'll keep the udev fix for Groovy and SRU that fix for Focal and Bionic and upload to the PPA as well. After all that is done, I'll tell kernel team to revert the bcache patch on Bionic, Focal and Groovy kernels since it is not needed and will reduce their delta and reduce chances of regressions over time. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1861941 Title: bcache by-uuid links disappear after mounting bcache0 Status in bcache-tools package in Ubuntu: In Progress Status in systemd package in Ubuntu: In Progress Status in bcache-tools source package in Bionic: In Progress Status in systemd source package in Bionic: In Progress Status in bcache-tools source package in Focal: In Progress Status in systemd source package in Focal: In Progress Bug description: 1. root@ubuntu:~# lsb_release -rd Description: Ubuntu Focal Fossa (development branch) Release: 20.04 2. root@ubuntu:~# lsb_release -rd Description: Ubuntu Focal Fossa (development branch) Release: 20.04 root@ubuntu:~# apt-cache policy linux-image-virtual linux-image-virtual: Installed: 5.4.0.12.15 Candidate: 5.4.0.12.15 Version table: *** 5.4.0.12.15 500 500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages 100 /var/lib/dpkg/status root@ubuntu:~# apt-cache policy linux-image-5.4.0-12-generic linux-image-5.4.0-12-generic: Installed: 5.4.0-12.15 Candidate: 5.4.0-12.15 Version table: *** 5.4.0-12.15 500 500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages 100 /var/lib/dpkg/status 3. mount /dev/bcache0 && ls -al /dev/bcache/by-uuid/ + ls -al /dev/bcache/by-uuid/ total 0 drwxr-xr-x 2 root root 60 Feb 4 23:31 . drwxr-xr-x 3 root root 60 Feb 4 23:31 .. lrwxrwxrwx 1 root root 13 Feb 4 23:31 abdfd1f6-44ce-4266-91db-24667b9ae51a -> ../../bcache0 4. root@ubuntu:~# ls -al /dev/bcache/by-uuid ls: cannot access '/dev/bcache/by-uuid': No such file or directory ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-12-generic 5.4.0-12.15 ProcVersionSignature: Ubuntu 5.4.0-12.15-generic 5.4.8 Uname: Linux 5.4.0-12-generic x86_64 ApportVersion: 2.20.11-0ubuntu16 Architecture: amd64 Date: Tue Feb 4 23:31:52 2020 ProcEnviron: TERM=xterm-256color PATH=(custom, no user) LANG=C.UTF-8 SHELL=/bin/bash SourcePackage: linux-signed-5.4 UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/bcache-tools/+bug/1861941/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
