Hi-
> On Feb 12, 2016, at 1:41 AM, Toshiaki Makita <makita.toshiaki@xxxxxxxxxxxxx> wrote:
>
> statd calls atexit(statd_unregister) to unregister statd service on exit,
> which actually has a side-effect that ha_callout() unregisters statd
> service even when the child callout process exits on execl() failure.
>
> Certain clustering software's deployment script adds -H option with its
> specified file non-existent, when it is configured not to use callout.
> In other words, -H seems to be used no matter if callout is needed or not,
> but when callout is unnecessary, the specified callout program is not
> deployed.
> This causes statd not to work once a lock is requested by its NFS client,
> as execl() in ha_callout() results in ENOENT and exit() of the child
> process calls exit-handler statd_unregister(). Eventually, the NFS client
> gets stuck with messages "lockd: cannot monitor xxx" on the NFS server.
>
> Although this may not be an expected way of using -H option, it would be
> better if statd could continue to work even in that situation. Also,
> execl() could fail for other reasons like ENFILE and EIO, where statd
> service should not be unregistered as well.
> Call _exit(), which does not call any exit-handlers, instead of exit() to
> take care of those situations and make statd more reliable.
OK, but I think the explanation could be simpler? It doesn't
seem like a matter of "it would be better if" but more like
"a forked child must not unregister the statd RPC server."
In other words, this seems like a real bug to me, not an
enhancement.
Reviewed-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> Signed-off-by: Toshiaki Makita <makita.toshiaki@xxxxxxxxxxxxx>
> ---
> support/include/ha-callout.h | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/support/include/ha-callout.h b/support/include/ha-callout.h
> index 1164336..a454bdb 100644
> --- a/support/include/ha-callout.h
> +++ b/support/include/ha-callout.h
> @@ -47,7 +47,7 @@ ha_callout(char *event, char *arg1, char *arg2, int arg3)
> arg3 < 0 ? NULL : buf,
> NULL);
> perror("execl");
> - exit(2);
> + _exit(2);
> case -1: perror("fork");
> break;
> default: pid = waitpid(pid, &ret, 0);
> --
> 1.7.1
>
>
>
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--
Chuck Lever
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