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From: Simon Kirby <sim@hostway.ca>
To: Yan-Pai Chen <yanpai.chen@gmail.com>
Cc: linux-nfs@vger.kernel.org
Subject: Re: [3.2.5] NFSv3 CLOSE_WAIT hang
Date: Tue, 11 Sep 2012 12:40:51 -0700	[thread overview]
Message-ID: <20120911194051.GB11160@hostway.ca> (raw)
In-Reply-To: <loom.20120910T105944-416@post.gmane.org>

On Mon, Sep 10, 2012 at 09:00:37AM +0000, Yan-Pai Chen wrote:

> Hi Trond,
> 
> Apologies for my late response.
> Upgrading to kernel 3.5 requires some effort. I am still working on it.
> 
> After applying your patch on 3.3 kernel, the problem is gone when using UDP 
> mounts.
> But it remains hang in the case of NFS over TCP mounts. 
> 
> I reproduced the problem by executing mm/mtest06_3 (i.e. mmap3) in the LTP test 
> suite repeatedly.
> About less than 200 times, it eventually ran into the CLOSE_WAIT hang.
> I got the following messages after enabling rpc_debug & nfs_debug:
> 
> 47991 0001    -11 cf2910e0   (null)        0 c0243f40 nfsv3 WRITE 
> a:call_reserveresult q:xprt_sending
> 47992 0001    -11 cf2910e0   (null)        0 c0243f40 nfsv3 WRITE 
> a:call_reserveresult q:xprt_sending
> 47993 0001    -11 cf2910e0   (null)        0 c0243f40 nfsv3 WRITE 
> a:call_reserveresult q:xprt_sending
> 47994 0001    -11 cf2910e0   (null)        0 c0243f40 nfsv3 WRITE 
> a:call_reserveresult q:xprt_sending
> 47995 0001    -11 cf2910e0   (null)        0 c0243f40 nfsv3 WRITE 
> a:call_reserveresult q:xprt_sending
> ...

Hello!

This problem still bites us rarely, and we've been using TCP NFS for some
time. However, our case seems to be narrowed it down to a very long
storage hang on the knfsd side. If storage never has any problems, we
don't see the NFS client hang. I was going to try to make a test-case by
forcing the server to hang, but I never got around to this. Meanwhile,
I've been running the clients with the debugging patches I posted
earlier, and it always prints the 'xprt_force_disconnect(): setting
XPRT_CLOSE_WAIT" warning before hanging. If Apache is in sendfile() at
the time, it seems to get stuck forever; otherwise, it might recover.

http://www.spinics.net/lists/linux-nfs/msg29495.html
http://0x.ca/sim/ref/3.2.10/dmesg

I suppose we could try 3.5 at this point.

Simon-

  reply	other threads:[~2012-09-11 19:40 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-09 19:45 [3.1-rc4] NFSv3 client hang Simon Kirby
2011-09-09 23:18 ` Trond Myklebust
2011-10-20 19:03   ` Simon Kirby
2012-03-01 22:55     ` Simon Kirby
2012-03-02  0:25       ` Simon Kirby
2012-03-02 18:49         ` [3.2.5] NFSv3 CLOSE_WAIT hang Simon Kirby
2012-09-05  7:49           ` Yan-Pai Chen
2012-09-05 15:09             ` Myklebust, Trond
2012-09-07 13:57               ` Dick Streefland, rnews
2012-09-07 14:13                 ` Myklebust, Trond
2012-09-07 14:33                   ` Dick Streefland, rnews
2012-09-07 15:46                     ` Myklebust, Trond
2012-09-08 19:32                       ` Dick Streefland, rnews
2012-09-10  9:00                         ` Yan-Pai Chen
2012-09-11 19:40                           ` Simon Kirby [this message]
2012-09-11 22:17                             ` Myklebust, Trond
2012-09-13  5:22                               ` Yan-Pai Chen
2012-09-13 13:32                                 ` Myklebust, Trond
2012-09-21  7:30                                   ` Yan-Pai Chen
     [not found]                             ` <1347401844.15208.17.camel@lade.trondhjem.org>
2012-09-12 20:54                               ` Myklebust, Trond
2012-09-19 22:01                                 ` Simon Kirby
2012-09-19 22:11                                   ` Myklebust, Trond
2012-10-12  8:15                                     ` Simon Kirby

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