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Date: Tue, 12 Feb 2002 16:39:51 -0800
From: Andrew Morton <akpm@zip.com.au>
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To: Alan Cox <alan@lxorguk.ukuu.org.uk>
CC: Rik van Riel <riel@conectiva.com.br>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch] sys_sync livelock fix
In-Reply-To: <Pine.LNX.4.33L.0202122215020.12554-100000@imladris.surriel.com> from "Rik van Riel" at Feb 12, 2002 10:15:38 PM <E16anPg-0003cy-00@the-village.bc.nu>
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Alan Cox wrote:
> 
> > I don't see why it should be different for applications
> > that write data after sync has started.
> 
> The guarantee about data written _before_ the sync started is also being
> broken unless I misread the code

That would be very broken.

The theory is: newly dirtied buffers are added at the "new"
end of the LRU.  write_some_buffers() starts at the "old"
end of the LRU.

So if write_unlock_buffers writes out the "oldest"
nr_buffers_type[BUF_DIRTY] buffers, then it knows
that it has written out everything which was dirty
at the time it was called.

Or did I miss something?

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