[PATCH 00/24] vfs: require filesystems to explicitly opt-in to lease support

[Christoph Hellwig]

On Tue, Jan 13, 2026 at 09:54:15AM +0100, Christian Brauner wrote:
> I don't think we want to expose cgroupfs via NFS that's super weird.
> It's like remote partial resource management and it would be very
> strange if a remote process suddenly would be able to move things around
> in the cgroup tree. So I would prefer to not do this.
> 
> So my preference would be to really sever file handles from the export
> mechanism so that we can allow stuff like pidfs and nsfs and cgroupfs to
> use file handles via name_to_handle_at() and open_by_handle_at() without
> making them exportable.

I don't understand this discussion.  If someone really wants to
expose say cgroupfs to the network they'll find a way, be that using
a userspace nfs server, samba, 9p or a custom fuse thing.  What's the
benefit of explicitly prohibiting a knfsd export?

(not that I think any of this makes much sense to start with)