Re: [PATCH] nlm_shutdown_hosts_net() cleanup

From: Jeff Layton
Date: Mon Oct 30 2017 - 11:49:08 EST


On Mon, 2017-10-30 at 10:49 -0400, J. Bruce Fields wrote:
> On Mon, Oct 30, 2017 at 04:47:58PM +0300, Vasily Averin wrote:
> > nlm_complain_hosts() walk through nlm_server_hosts hlist that should be
> > protected by nlm_host_mutex.
>
> I haven't looked at the NLM locking in ages. Do we know who else might
> actually be accessing this list concurrently?
>
> --b.
>

Since this is a per-net-ns shutdown, I suppose you could have concurrent
rpc.nfsd's shutting down different namespaces. Holding the mutex for
longer looks like a reasonable fix.

That said...I don't think lockd was ever properly namespace-ified. YMMV
here.

> >
> > Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
> > ---
> > fs/lockd/host.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/fs/lockd/host.c b/fs/lockd/host.c
> > index d716c99..089c1d7 100644
> > --- a/fs/lockd/host.c
> > +++ b/fs/lockd/host.c
> > @@ -617,9 +617,8 @@ nlm_shutdown_hosts_net(struct net *net)
> >
> > /* Then, perform a garbage collection pass */
> > nlm_gc_hosts(net);
> > - mutex_unlock(&nlm_host_mutex);
> > -
> > nlm_complain_hosts(net);
> > + mutex_unlock(&nlm_host_mutex);
> > }
> >
> > /*
> > --
> > 2.7.4
>
> --
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Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>