On Fri, Jul 26, 2019 at 07:46:18PM -0500, Eric W. Biederman wrote: > If someone had bothered to actually look at how I was proposing to clean > things up before the new mount api we would already have that. Sigh. > > You should be able to get away with something like this which moves the > checks earlier and makes things clearer. My old patch against the pre > new mount api code. Check your instances of ->permission(); AFAICS in all cases it's (in current terms) return ns_capable(fc->user_ns, CAP_SYS_ADMIN) ? 0 : -EPERM; In principle I like killing FS_USERNS_MOUNT flag, but when a method is always either NULL or exact same function...