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Date: Wed, 13 Feb 2002 16:53:04 -0800
From: Andrew Morton <akpm@zip.com.au>
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To: Daniel Phillips <phillips@bonn-fries.net>
CC: Bill Davidsen <davidsen@tmr.com>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch] sys_sync livelock fix
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Daniel Phillips wrote:
> 
> What's the theory behind writing the data both before and after the commit?

see fsync_dev().  It starts I/O against existing dirty data, then
does various fs-level syncy things which can produce more dirty
data - this is where ext3 runs its commit, via brilliant reverse
engineering of its calling context :-(.  It then again starts I/O
against new dirty data then waits on it again.  And then again.

There's quite a lot of overkill there.  But that's OK, as long
as it terminates sometime.

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