On Wed, 6 Mar 2024 at 11:57, Christian Brauner <brauner@xxxxxxxxxx> wrote: > There's a tiny wrinkle though. We currently have no way of letting > userspace know whether a filesystem supports the new mount API or not > (see that mount option probing systemd does we recently discussed). So > if say mount(8) remounts debugfs with mount options that were ignored in > the old mount api that are now rejected in the new mount api users now > see failures they didn't see before. > > For the user it's completely intransparent why that failure happens. For > them nothing changed from util-linux's perspective. So really, we should > probably continue to ignore old mount options for backward compatibility. The reject behavior could be made conditional on e.g. an fsopen() flag. I.e. FSOPEN_REJECT_UNKNOWN would make unknown options be always rejected. Without this flag fsconfig(2) would behave identically before/after the conversion. Thanks, Miklos
