From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: Re: [PATCH] gssd: unblock DNOTIFY_SIGNAL in case it was blocked. Date: Tue, 11 Nov 2008 14:09:40 -0500 Message-ID: <20081111190940.GA8775@fieldses.org> References: <18712.46537.9006.490726@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kwc@citi.umich.edu, linux-nfs@vger.kernel.org To: Neil Brown Return-path: Received: from mail.fieldses.org ([66.93.2.214]:57962 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750940AbYKKTJm (ORCPT ); Tue, 11 Nov 2008 14:09:42 -0500 In-Reply-To: <18712.46537.9006.490726-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Nov 11, 2008 at 09:29:29AM +1100, Neil Brown wrote: > > I have a situation where rpc.gssd appears to not be working. > Mount attempts which need to communicate with it block. > > I've narrowed down the problem to that fact that all realtime signals > have been blocked. This means that DNOTIFY_SIGNAL (which is a > realtime signal) is never delivered, so gssd never rescans the > rpc_pipe/nfs directory. > > I haven't figured out why the signals are blocked yet, but having > rpc.gssd fail mysteriously in that situation isn't pleasant. > > So I wonder what people think of the following patch. It simply > unblocks the signal. Alternately we can check if it is blocked and > warn - I'm not really sure of the significance of blocking all these > signals. Maybe it's wrong to just unblock them. So we don't know what it is that's doing the blocking? > As an aside, maybe we could change gssd_run to use "ppoll" rather than > "poll". Then it would not have to wake up every 500msec to see if it > missed a signal. We would probably have to check kernel version was at > least 2.6.16.... Yes. (What does glibc itself do in the ppoll library call if the kernel doesn't support it?) --b. > diff --git a/utils/gssd/gssd_main_loop.c b/utils/gssd/gssd_main_loop.c > index 84f04e9..b9f3a06 100644 > --- a/utils/gssd/gssd_main_loop.c > +++ b/utils/gssd/gssd_main_loop.c > @@ -99,6 +99,7 @@ gssd_run() > int ret; > struct sigaction dn_act; > int fd; > + sigset_t set; > > /* Taken from linux/Documentation/dnotify.txt: */ > dn_act.sa_sigaction = dir_notify_handler; > @@ -106,6 +107,11 @@ gssd_run() > dn_act.sa_flags = SA_SIGINFO; > sigaction(DNOTIFY_SIGNAL, &dn_act, NULL); > > + /* just in case the signal is blocked... */ > + sigemptyset(&set); > + sigaddset(&set, DNOTIFY_SIGNAL); > + sigprocmask(SIG_UNBLOCK, &set, NULL); > + > if ((fd = open(pipefs_nfsdir, O_RDONLY)) == -1) { > printerr(0, "ERROR: failed to open %s: %s\n", > pipefs_nfsdir, strerror(errno)); > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html