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));
> --
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