[PATCH 13/17] watch_queue: Implement mount topology and attribute change notifications [ver #5]

[Miklos Szeredi]

On Thu, Jul 23, 2020 at 12:48 PM David Howells <dhowells at redhat.com> wrote:

>
> > >                 __u32   topology_changes;
> > >                 __u32   attr_changes;
> > >                 __u32   aux_topology_changes;
> >
> > Being 32bit this introduces wraparound effects.  Is that really worth it?
>
> You'd have to make 2 billion changes without whoever's monitoring getting a
> chance to update their counters.  But maybe it's not worth it putting them
> here.  If you'd prefer, I can make the counters all 64-bit and just retrieve
> them with fsinfo().

Yes, I think that would be preferable.

> > >         n->watch.info & NOTIFY_MOUNT_IS_RECURSIVE if true indicates that
> > >         the notifcation was generated by an event (eg. SETATTR) that was
> > >         applied recursively.  The notification is only generated for the
> > >         object that initially triggered it.
> >
> > Unused in this patchset.  Please don't add things to the API which are not
> > used.
>
> Christian Brauner has patches for mount_setattr() that will need to use this.

Fine, then that patch can add the flag.

Thanks,
Miklos