From: Neil Brown <neilb@suse.de>
Subject: Re: Regression: NFS locking hangs when statd not running.
Date: Tue, 24 Oct 2006 11:26:43 +1000
Message-ID: <17725.27603.724326.910277@cse.unsw.edu.au>
References: <17720.41873.549441.330938@cse.unsw.edu.au>
	<20061020124119.GE27351@suse.de>
	<76bd70e30610200600o2269db3ex2448982fb3e25d46@mail.gmail.com>
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Cc: Olaf Kirch <okir@suse.de>, Takashi Iwai <tiwai@suse.de>,
	nfs@lists.sourceforge.net
To: "Chuck Lever" <chucklever@gmail.com>
In-Reply-To: message from Chuck Lever on Friday October 20
Sender: nfs-bounces@lists.sourceforge.net
Errors-To: nfs-bounces@lists.sourceforge.net

On Friday October 20, chucklever@gmail.com wrote:
> 
> Copying the intr flag makes sense.  Neil, I'd like to see your patch
> address this too.

I'll see what I can do... but not for lockd requests.  See previous mail

> 
> The hard v. soft issue is more difficult.  The semantic you are
> requesting for the local statd is clearly "soft" and that's what you
> say you always want.  Otherwise copying the soft flag makes sense.
> 
> Maybe you can re-use the soft flag and expose a way to set the soft
> timeout for the mon client to get the exact behavior you want?

It's not really about timeouts - or about 'soft'.  It is about getting
a definite 'no' answer (either from portmap or the network stack) and
believing it, which is only safe when talking to a local service
.... hmmm.  Maybe that is also safe when doing the initial 'ping'.
That is currently always 'soft' and presumably 'expects' the server to
be there and functional so a 'no' reply could reasonably be believed
there.

Looking more at where and initial ping is used, I notice that the
lockd client does a (soft) ping first.  So if you have a hard mount,
the first lock request can still fail due to an unresponsive server
because the ping will fail... Shouldn't lockd clients be created with
NO_PING ??

NeilBrown

> 
> -- 
> "We who cut mere stones must always be envisioning cathedrals"
>    -- Quarry worker's creed
A colleague as a message on his wall something like:
  If you want to build great boats, teach your workers to yearn for
  the wide open oceans.

or something like that. :-)

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