On Tue, 2023-07-18 at 16:38 +1000, NeilBrown wrote:
> lockd allows SIGKILL and responds by dropping all locks and restarting
> the grace period. This functionality has been present since 2.1.32 when
> lockd was added to Linux.
>
> This functionality is undocumented and most liked added as a useful
> debug aid. When there is a need to drop locks, the best approach is
> using /proc/fs/nfsd/unlock_*.
>
> This patch removes the handling of SIGKILL as part of preparation for
> removing all signal handling from sunrpc service threads.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/lockd/svc.c | 24 ------------------------
> 1 file changed, 24 deletions(-)
>
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index 22d3ff3818f5..614faa5f69cd 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -45,7 +45,6 @@
>
> #define NLMDBG_FACILITY NLMDBG_SVC
> #define LOCKD_BUFSIZE (1024 + NLMSVC_XDRSIZE)
> -#define ALLOWED_SIGS (sigmask(SIGKILL))
>
> static struct svc_program nlmsvc_program;
>
> @@ -111,19 +110,6 @@ static void set_grace_period(struct net *net)
> schedule_delayed_work(&ln->grace_period_end, grace_period);
> }
>
> -static void restart_grace(void)
> -{
> - if (nlmsvc_ops) {
> - struct net *net = &init_net;
> - struct lockd_net *ln = net_generic(net, lockd_net_id);
> -
> - cancel_delayed_work_sync(&ln->grace_period_end);
> - locks_end_grace(&ln->lockd_manager);
> - nlmsvc_invalidate_all();
> - set_grace_period(net);
> - }
> -}
> -
> /*
> * This is the lockd kernel thread
> */
> @@ -138,9 +124,6 @@ lockd(void *vrqstp)
> /* try_to_freeze() is called from svc_recv() */
> set_freezable();
>
> - /* Allow SIGKILL to tell lockd to drop all of its locks */
> - allow_signal(SIGKILL);
> -
> dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
>
> /*
> @@ -154,12 +137,6 @@ lockd(void *vrqstp)
> /* update sv_maxconn if it has changed */
> rqstp->rq_server->sv_maxconn = nlm_max_connections;
>
> - if (signalled()) {
> - flush_signals(current);
> - restart_grace();
> - continue;
> - }
> -
> timeout = nlmsvc_retry_blocked();
>
> /*
> @@ -174,7 +151,6 @@ lockd(void *vrqstp)
>
> svc_process(rqstp);
> }
> - flush_signals(current);
> if (nlmsvc_ops)
> nlmsvc_invalidate_all();
> nlm_shutdown_hosts();
>
>
Nice to finally do this!
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
