Comment 3 for bug 1159256

Grizzly (sven-witterstein) wrote :

There seems to be a general problem i.e. crc32 (and more) need be in the initrd to enable multi-device or crypted btrfs-es to be mounted. It may helpt to update-initramfs -u after btrfs-entries in the fstab have changed.

Workaround: remove the fs in question from fstab (comment it) and put
btrfs device scan
mount -L <your crypted poolname here> /<your mountpoint>

in /etc/rc.local...