On Fri, Jun 01, 2018 at 09:27:43AM +0100, David Howells wrote: > Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > > Instead of overloading this on open having a specific syscalls just > > > seems like a much saner idea. > > > > It's not just mount API; these can be used independently of that. > > Think of the uses where you pass those to ...at() and you'll see > > a bunch of applications of that thing. > > I kind of agree with Christoph on this point. Yes, you can use the resultant > fd for other things, but that doesn't mean it has to be obtained initially > through open() or openat() rather than, say, a new pick_mount() syscall. > > Further, having more parameters available gives us the opportunity to change > the settings on any mounts we create at the point of creation. open_subtree(int dirfd, const char *pathname, int flags), then? How would flags be interpreted? What I see mapping at that thing is * equivalent of O_PATH open * clone subtree, O_PATH open root * clone one mount, O_PATH open root and apparently you want to add (orthogonal to that) * make shared/slave/private/unbindable * ditto with recursion? * same for nodev/nosuid/noexec/noatime/nodiratime/relatime/ro/? as well as usual AT_... flags (empty path, follow) Choose the encoding...
