After using a write-around bcache on the root device of an old laptop for more than a year (HD + SD card), I finally found out that some severe filesystem corruptions I was facing -- which lead me to resort to backups and reinstall everything twice (!!) -- were due to bcache corruption on the cache device after rebooting uppon updating/upgrading the kernel.
The workaround for that is rather "easy", since it is a read cache: When the boot process says my device is corrupted beyond automatic repair habilities, I just have to remove the cache device before doing a manual fsck, recreate the cache and register it again. -- BTW, never try to fsck an allegedly corrupted file system with a corrupted write-around bcache because, then, you will really corrupt your data.
Question: what would be a possible way to prevent this corruption? I use archlinux, therefore, always with a recent version of everything -- the kernel now is 4.19.4.