Can't boot from LUKS encrypted btrfs anymore

For the sake of completeness:
After some search across the Net I joined the BTRFS mailing list and some other kind souls looked at it.
The gist is, the FS is wrecked but I can mount it RO to get some of the new data I couldn’t backup to this point.
Then I have to re-format/re-install … :expressionless:
The thread:
Thanks again, Michael.