Re: [BUG] DVD writing in 2.6.6-rc2

From: Jens Axboe
Date: Wed Apr 28 2004 - 06:33:54 EST


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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