Comment 12 for bug 1861941

It appears that it's always been a touch racy. Curtin does not create bcaches like the script does (make-bcache --wipe-bcache -C /dev/sdc -B /dev/sdb), rather we make the cache-dev and backing dev separately, and then attach them by echoing the cacheset uuid into the bcache device attach sysfs file. The issue is after install when we first boot the system that has one or more bcache devices, we *sometimes* don't see the /dev/bcache/by-uuid symlinks show up.

Focal _always_ fails; Eoan works sometimes, in our testing, bionic has never failed; though clearly it suffers from the same (or similar) race.