On Fri, May 30, 2025 at 07:43:48PM +0100, Al Viro wrote: > On Fri, May 30, 2025 at 02:20:39PM +0200, Mickaël Salaün wrote: > > > Without access to mount_lock, what would be the best way to fix this > > Landlock issue while making it backportable? > > > > > > > > If we update path_parent in this patchset with choose_mountpoint(), > > > and use it in Landlock, we will close this race condition, right? > > > > choose_mountpoint() is currently private, but if we add a new filesystem > > helper, I think the right approach would be to expose follow_dotdot(), > > updating its arguments with public types. This way the intermediates > > mount points will not be exposed, RCU optimization will be leveraged, > > and usage of this new helper will be simplified. > > IMO anything that involves struct nameidata should remain inside > fs/namei.c - something public might share helpers with it, but that's Strongly agree.
