linux-kernel - Re: lockdep warning with LTP dio test (v2.6.24-rc6-125-g5356f66)

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Message-Id: <200801251116.13690.chris.mason@oracle.com>
Date:	Fri, 25 Jan 2008 11:16:13 -0500
From:	Chris Mason <chris.mason@...cle.com>
To:	Jan Kara <jack@...e.cz>
Cc:	Zach Brown <zach.brown@...cle.com>, Erez Zadok <ezk@...sunysb.edu>,
	linux-kernel@...r.kernel.org, ext3-users@...hat.com,
	Peter Zijlstra <peterz@...radead.org>,
	linux-fsdevel@...r.kernel.org
Subject: Re: lockdep warning with LTP dio test (v2.6.24-rc6-125-g5356f66)

On Friday 25 January 2008, Jan Kara wrote:

> > If ext3's DIO code only touches transactions in get_block, then it can
> > violate data=ordered rules.  Basically the transaction that allocates
> > the blocks might commit before the DIO code gets around to writing them.
> >
> > A crash in the wrong place will expose stale data on disk.
>
>   Hmm, I've looked at it and I don't think so - look at the rationale in
> the patch below... That patch should fix the lock-inversion problem (at
> least I see no lockdep warnings on my test machine).
>

Ah ok, when I was looking at this I was allowing holes to get filled without 
falling back to buffered.  But, with the orphan inode entry protecting things 
I see how you're safe with this patch.

-chris
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