Date: Wed, 28 Apr 2004 13:30:56 +0200
From: Jens Axboe <axboe@suse.de>
To: Moritz Muehlenhoff <jmm@informatik.uni-bremen.de>
Cc: linux-kernel@vger.kernel.org, ken@kenjo.org, cw@f00f.org
Subject: Re: [BUG] DVD writing in 2.6.6-rc2
Message-ID: <20040428113056.GA2150@suse.de>
References: <1083088772.2679.11.camel@tiger> <20040427183607.GA3011@suse.de> <8n23m1-g22.ln1@legolas.mmuehlenhoff.de>
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On Wed, Apr 28 2004, Moritz Muehlenhoff wrote:
> Jens Axboe wrote:
> >> I have a problem when using growisofs version 5.19.
> >> 
> >> The problem is that in the very end when gowisofs tries to flush the
> >> cache. When stracing the process I can see it sits in a call to poll
> >> that never returns. 
> >
> > I noted the same thing yesterday with cdrdao, so yours is not an
> > isolated incident. I'll debug it tomorrow.
> 
> I can confirm this bug for kernel 2.6.3-rc4 as well, so it's not too recent.
> I found the following on my console after quitting k3b ungracefully, maybe

This is really strange, I haven't been able to locate a kernel problem.
Looking at command traces, cdrdao issues two FLUSH_CACHE commands when
ending the writes. The last commands are:

0x2a (last real write)
0x35 (first flush cache) (takes about 10 seconds to complete)
0x00 (test unit ready)
0x51 (read disc info, length 4)
0x35 (2nd flush cache) -> never completes

That last sync cache never generates an interrupt, so cdrdao gets stuck
forever waiting on it. I cannot even reproduce this with a test case

-- 
Jens Axboe

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