rear116 has adaptions_for_btrfs_for_SLE12.diff
that provides adaptions and enhancements for the
sophisticated btrfs structure on SLE12.
As far as I see the only thing that I used which makes
my current adaptions_for_btrfs_for_SLE12.diff specific
for SLE12 is that I used the SLE12 btrfs default
subvolume name '/@' in a hardcoded way.
On SLE12 we have:
-----------------------------------------------------------------------
# findmnt -t btrfs | cut -b-61
TARGET SOURCE
/ /dev/sda2[/@]
|-/.snapshots /dev/sda2[/@/.snapshots]
|-/var/spool /dev/sda2[/@/var/spool]
|-/var/tmp /dev/sda2[/@/var/tmp]
|-/var/lib/named /dev/sda2[/@/var/lib/named]
|-/var/opt /dev/sda2[/@/var/opt]
|-/usr/local /dev/sda2[/@/usr/local]
|-/tmp /dev/sda2[/@/tmp]
|-/var/lib/pgsql /dev/sda2[/@/var/lib/pgsql]
|-/home /dev/sda2[/@/home]
|-/var/crash /dev/sda2[/@/var/crash]
|-/opt /dev/sda2[/@/opt]
|-/var/log /dev/sda2[/@/var/log]
|-/boot/grub2/i386-pc /dev/sda2[/@/boot/grub2/i386-pc]
|-/var/lib/mailman /dev/sda2[/@/var/lib/mailman]
|-/srv /dev/sda2[/@/srv]
`-/boot/grub2/x86_64-efi /dev/sda2[/@/boot/grub2/x86_64-efi]
# btrfs subvolume get-default /
ID 257 gen 2260 top level 5 path @
-----------------------------------------------------------------------
On openSUSE 13.2 we have
-----------------------------------------------------------------------
# findmnt -t btrfs | cut -b-59
TARGET SOURCE
/ /dev/sda2
|-/.snapshots /dev/sda2[/.snapshots]
|-/var/spool /dev/sda2[/var/spool]
|-/var/tmp /dev/sda2[/var/tmp]
|-/var/log /dev/sda2[/var/log]
|-/var/opt /dev/sda2[/var/opt]
|-/var/lib/mailman /dev/sda2[/var/lib/mailman]
|-/var/crash /dev/sda2[/var/crash]
|-/var/lib/named /dev/sda2[/var/lib/named]
|-/var/lib/pgsql /dev/sda2[/var/lib/pgsql]
|-/opt /dev/sda2[/opt]
|-/tmp /dev/sda2[/tmp]
|-/usr/local /dev/sda2[/usr/local]
|-/boot/grub2/i386-pc /dev/sda2[/boot/grub2/i386-pc]
|-/srv /dev/sda2[/srv]
`-/boot/grub2/x86_64-efi /dev/sda2[/boot/grub2/x86_64-efi]
# btrfs subvolume get-default /
ID 5 (FS_TREE)
-----------------------------------------------------------------------
If I could change it to deal with the btrfs default subvolume
in a generic way, I hope it could work for any btrfs structure.
For the history of this issue see
https://github.com/rear/rear/issues/497