On Mon, 2023-09-25 at 12:06 +1000, NeilBrown wrote:
> The error paths in nfsd_svc() are needlessly complex and can result in a
> final call to svc_put() without nfsd_last_thread() being called. This
> results in the listening sockets not being closed properly.
>
> The per-netns setup provided by nfsd_startup_new() and removed by
> nfsd_shutdown_net() is needed precisely when there are running threads.
> So we don't need nfsd_up_before. We don't need to know if it *was* up.
> We only need to know if any threads are left. If none are, then we must
> call nfsd_shutdown_net(). But we don't need to do that explicitly as
> nfsd_last_thread() does that for us.
>
> So simply call nfsd_last_thread() before the last svc_put() if there are
> no running threads. That will always do the right thing.
>
> Also discard:
> pr_info("nfsd: last server has exited, flushing export cache\n");
> It may not be true if an attempt to start the first server failed, and
> it isn't particularly helpful and it simply reports normal behaviour.
>
Thanks. Removing that is long overdue.
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/nfsd/nfssvc.c | 14 ++++----------
> 1 file changed, 4 insertions(+), 10 deletions(-)
>
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index c5890cdfe97b..d6122bb2d167 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -572,7 +572,6 @@ static void nfsd_last_thread(struct net *net)
> return;
>
> nfsd_shutdown_net(net);
> - pr_info("nfsd: last server has exited, flushing export cache\n");
> nfsd_export_flush(net);
> }
>
> @@ -786,7 +785,6 @@ int
> nfsd_svc(int nrservs, struct net *net, const struct cred *cred)
> {
> int error;
> - bool nfsd_up_before;
> struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> struct svc_serv *serv;
>
> @@ -806,8 +804,6 @@ nfsd_svc(int nrservs, struct net *net, const struct cred *cred)
> error = nfsd_create_serv(net);
> if (error)
> goto out;
> -
> - nfsd_up_before = nn->nfsd_net_up;
> serv = nn->nfsd_serv;
>
> error = nfsd_startup_net(net, cred);
> @@ -815,17 +811,15 @@ nfsd_svc(int nrservs, struct net *net, const struct cred *cred)
> goto out_put;
> error = svc_set_num_threads(serv, NULL, nrservs);
> if (error)
> - goto out_shutdown;
> + goto out_put;
> error = serv->sv_nrthreads;
> - if (error == 0)
> - nfsd_last_thread(net);
> -out_shutdown:
> - if (error < 0 && !nfsd_up_before)
> - nfsd_shutdown_net(net);
> out_put:
> /* Threads now hold service active */
> if (xchg(&nn->keep_active, 0))
> svc_put(serv);
> +
> + if (serv->sv_nrthreads == 0)
> + nfsd_last_thread(net);
> svc_put(serv);
> out:
> mutex_unlock(&nfsd_mutex);
Nice cleanup.
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
