I used the YAST Partitioner to modify an external disk. When you invoke the partitioner, you get a message, that you should only continue when you know what you are doing. That is not sufficient: You should also be able to repair any damage that the YAST Partitioner does on your system!
The work on the external disk was all fine. But it additionally created two subvolumes and modified my /etc/fstab. See here
# diff -w /etc/fstab /.snapshots/339/snapshot/etc/fstab
33,34c33
< UUID=1c2fd857-5a24-4624-895e-af35e0b07762 /home btrfs subvol=/@/home 0 0
< /media/lvm/vg2-mlvm07/os-leap /home none bind 0 0
---
> /media/lvm/vg2-mlvm07/os-leap /home none defaults,bind 0 0
37,42c36,39
< UUID=c5c1e954-85e0-4e49-bef9-fbe37a9d049c /media/lvm/vg1-mlvm01 ext4 user_xattr 1 2
< /media/lvm/vg1-mlvm01/shared /home/bequimao/myshared none bind 0 0
< /media/lvm/vg1-mlvm01/shared /home/beq-jrt/myshared none bind 0 0
< /media/lvm/vg2-mlvm07/shared/Dokumente /home/bequimao/Dokumente none bind 0 0
< UUID=1c2fd857-5a24-4624-895e-af35e0b07762 /var/lib/portables btrfs subvol=/@/var/lib/portables 0 0
< UUID=1c2fd857-5a24-4624-895e-af35e0b07762 /var/lib/libvirt/images btrfs subvol=/@/var/lib/libvirt/images 0 0
---
> UUID=c5c1e954-85e0-4e49-bef9-fbe37a9d049c /media/lvm/vg1-mlvm01 ext4 defaults,user_xattr 1 2
> /media/lvm/vg1-mlvm01/shared /home/bequimao/myshared none defaults,bind 0 0
> /media/lvm/vg1-mlvm01/shared /home/beq-jrt/myshared none defaults,bind 0 0
> /media/lvm/vg2-mlvm07/shared/Dokumente /home/bequimao/Dokumente none defaults,bind 0 0
/var/lib/images was a symbolic link to another location. I do not want any virtual machine on btrfs!
The subvolume /@/home was already there, but empty and not mounted. After repair I found two entries for /home, and of course the partitioner remounted all entries of fstab, thus destroying my actual session. And of course, the system does no longer boot into a working desktop.
Thank God, there is btrfs and snapper, so that you can reset all changes easily!
Best regards,
Bequimão