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List:       linux-xfs
Subject:    Re: xfs_end_io_direct() with negative size?
From:       Nathan Scott <nathans () sgi ! com>
Date:       2006-08-14 0:22:58
Message-ID: 20060814102258.A2698880 () wobbly ! melbourne ! sgi ! com
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On Fri, Aug 11, 2006 at 10:43:12AM -0700, Zach Brown wrote:
> 
> So, I was lost in fs/direct-io.c chasing yet another bug when I noticed
> that a recent unrelated change might have changed the semantics of the
> end_io() call.
> 
>    http://www.kernel.org/hg/linux-2.6/?cs=34c151cf341f
> 
> Notice how that changes the aio path to set 'transferred' to -EIO based
> on dio->io_error before calling dio_complete() instead of after, like
> the sync path does with its possibly negative 'ret'.
> 
> So it looks like xfs_end_io_direct() can now get a -ve size if, say,
> someone unplugs a drive part-way through a dio+aio write.  There's an
> ASSERT() in there that makes me wonder if this is something we should be
> worrying about.

Its harmless.  It was written when there was no way a negative byte
count would be coming back at us from the dio code.  We should simply
remove the assert.

cheers.

-- 
Nathan


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