[$] Yet another try for fs-verity

The fs"verity mechanism has its origins in the Android project; its purposeis to make individual files read-only and enable the kernel to detectany modifications that might have been made, even if those changes happenoffline. Previous fs"verity implementations have run into criticism in thedevelopment community, and none have been merged. A newversion of the patch set was posted on May 23; it features achanged user-space API and may have a better chance of getting into themainline.