On 2016/02/13 0:40, Chuck Lever wrote: > Hi- 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. Thank you for your feedback. Here is a simpler one. If it looks fine to you, I'll send v2 with your Reviewed-by. --- -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. +Also, execl() could fail for other reasons like ENFILE or EIO as well. + +A forked child must not unregister the statd RPC server, so use +_exit(), which does not call any exit-handlers, instead of exit(). --- Regards, Toshiaki Makita -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
