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From: Paul Clements <paul.clements@steeleye.com>
To: Mike Snitzer <snitzer@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, david@dgreaves.com,
	Wouter Verhelst <w@uter.be>, Corey Minyard <cminyard@mvista.com>,
	nbd-general@lists.sourceforge.net
Subject: Re: [PATCH 2/2] NBD: allow hung network I/O to be cancelled
Date: Fri, 24 Aug 2007 15:09:17 -0400	[thread overview]
Message-ID: <46CF2CDD.5000802@steeleye.com> (raw)
In-Reply-To: <170fa0d20708241113y31d2ba95xf30c83c7c4c98cd2@mail.gmail.com>

Mike Snitzer wrote:
> On 8/24/07, Paul Clements <paul.clements@steeleye.com> wrote:
>> This patch allows NBD I/O to be cancelled when a network outage occurs.
>> Previously, I/O would just hang, and if enough I/O was hung in nbd, the
>> system (at least user-level) would completely hang until a TCP timeout
>> (default, 15 minutes) occurred.
>>
>> The patch introduces a new ioctl NBD_SET_TIMEOUT that allows a transmit
>> timeout value (in seconds) to be specified. Any network send that
>> exceeds the timeout will be cancelled and the nbd connection will be
>> shut down. I've tested with various timeout values and 6 seconds seems
>> to be a good choice for the timeout. If the NBD_SET_TIMEOUT ioctl is not
>> called, you get the old (I/O hang) behavior.
> 
> Hi Paul,
> 
> Thanks for implementing this!  Do you happen to have an associated
> nbd-client patch for userspace?  If not I'd be happy to coordinate
> with you and Wouter on a patch.

No, I don't. I just basically hardcoded my nbd-client to do a 6 second 
timeout by default, but Wouter will probably want to do something a 
little less hackish for the official nbd-client.

--
Paul

  reply	other threads:[~2007-08-24 19:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-08-24 17:06 [PATCH 1/2] NBD: set uninitialized devices to size 0 Paul Clements
2007-08-24 17:40 ` [PATCH 2/2] NBD: allow hung network I/O to be cancelled Paul Clements
2007-08-24 18:13   ` Mike Snitzer
2007-08-24 19:09     ` Paul Clements [this message]
2007-08-24 23:48 ` [PATCH 1/2] NBD: set uninitialized devices to size 0 Andrew Morton
2007-08-29  2:54   ` Bill Davidsen

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