/var/lib/machines error during update

[Cris70]

Today, while updating, I got this message:

(101/210) Installazione di: systemd-234-3.1.x86_64 .................................................................................................................................[fine]
Output aggiuntivo di rpm:
Making /var/lib/machines suitable for rollbacks...
Deleting empty /var/lib/machines directory/subvolume
Delete subvolume (no-commit): '/var/lib/machines'
Creating /var/lib/machines subvolume suitable for rollbacks.
failure (ioctl(BTRFS_IOC_SUBVOL_CREATE) failed, errno:17 (File exists))
warning: Please fix /var/lib/machines manually.

I do not have (anymore) a "machines" directory/subvolume under /var/lib. I also verified that there's no instruction in /etc/fstab to mount a /var/lib/machines subvolume.
So I simply created a "machines" subdirectory under /var/lib, but I'm not sure this is the right thing to do.
Hints?

Cris

[Cris70]

Doesn't anybody have a clue about this?
Nobody else with this problem?

TIA
Cris

[Cris70]

I solved my problem, so I'm reporting it here in the hope that it will help someone else in the future.

First of all: even if nobody replied to this thread, the problem is known and somebody already put some effort (or at least thought) in it.
First step I took was to examine the post-script of the systemd package, which was giving me the problem. Here is the post-installation script (emphasis added by me):

# Convert /var/lib/machines subvolume to make it suitable for
# rollbacks, if needed. See bsc#992573. The installer has been fixed
# to create it at installation time.
#
# The convertion might only be problematic for openSUSE distros
# (TW/Factory) where previous versions had already created the
# subvolume at the wrong place (via tmpfiles for example) and user
# started to populate and use it. In this case we'll let the user fix
# it manually.
#
# For SLE12 this subvolume was only introduced during the upgrade from
# v210 to v228 when we added this workaround. Note that the subvolume
# is still created at the wrong place due to the call to
# tmpfiles_create macro previously however it's empty so there
# shouldn't be any issues.
if [ $1 -gt 1 ]; then
        /usr/lib/systemd/scripts/fix-machines-btrfs-subvol.sh || :
fi

Looking at the script fix-machines-btrfs-subvol.sh I can see that everything works correctly, but for the last command: the one to create the subvolume. It fails because the subvolume already exists. This is weird, because the script should have deleted it a few lines before, and it did not produce an error. In fact I do not have a /var/lib/machines anymore, but by running the sudo btrfs subvolume list -a / command I see that the subvolume is still there.
Trying to delete it with sudo btrfs subvolume delete /var/lib/machines gave me an error (don't remember it exactly, but was something like "path do not exist").

So I started googling around and found this post that helped me find the solution: https://unix.stackexchange.com/quest...trfs-subvolume.
In the solution, the "second possibility" was the right one. I followed the instructions to mount the subvolume with ID=0 on /mnt and, from there, I was finally able to delete the subvolume with the command sudo btrfs subvolume delete /mnt/var/lib/machines.
After that, I unmounted the subvolume with ID=0 and then ran the command mksubvolume /var/lib/machines, which - at last! - succeeded.

I hope this helps!

Cris

[Knurpht]

Thanks for sharing, Cris. I saw your posts, but did not have any clue.