On Mon, Apr 06, 2020 at 09:34:08AM -0700, Linus Torvalds wrote: > On Mon, Apr 6, 2020 at 2:17 AM Karel Zak <kzak@xxxxxxxxxx> wrote: > > > > On Fri, Apr 03, 2020 at 04:30:24PM -0400, J. Bruce Fields wrote: > > > > > > nfs-utils/support/misc/mountpoint.c:check_is_mountpoint() stats the file > > > and ".." and returns true if they have different st_dev or the same > > > st_ino. Comparing mount ids sounds better. > > > > BTW, this traditional st_dev+st_ino way is not reliable for bind mounts. > > For mountpoint(1) we search the directory in /proc/self/mountinfo. > > These days you should probably use openat2() with RESOLVE_NO_XDEV. > > No need for any mountinfo or anything like that. Just look up the > pathname and say "don't cross mount-points", and you'll get an error > if it's a mount crossing lookup. OK, I can't see why that wouldn't work, thanks. --b. > > So this kind of thing is _not_ an argument for another kernel querying > interface. We got a new (and better) model for a lot of this. > > Linus
