[$] Authenticated Btrfs

Developers who are concerned about system integrity often put a fair amountof effort into ensuring that data stored on disk cannot be tampered withwithout being detected.Technologies like dm-verityand fs-verity are attempts to solve thisproblem, as is the recently covered integritypolicy enforcement security module. More Recently, Johannes Thumshirnhas posted a patchseries adding filesystem-level authentication to Btrfs; it promises toprovide integrity with a surprisingly small amount of code.