On Tue, Dec 01, 2020 at 11:50:25AM +0100, Christoph Hellwig wrote:

The READ_ONCE still looks suspect as it generally needs to be paired
with a WRITE_ONCE.  The rest looks sane to me.

I think the READ_ONCE() can be dropped from this patch. At this point in
the series we don't allowing changing the vfsmount's userns. The infra
to do that is only introduced as almost the last patch in the series and
there we immediately use smp_load_acquire() and smp_store_release().

Thanks!
Christian