From: Andrew Morton <akpm@osdl.org>
Subject: Re: Boot failure with ext2 and initrds
Date: Thu, 16 Nov 2006 01:48:09 -0800
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Cc: cmm@us.ibm.com, Hugh Dickins <hugh@veritas.com>,
	Mel Gorman <mel@skynet.ie>,
	"Martin J. Bligh" <mbligh@mbligh.org>,
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To: Alex Tomas <alex@clusterfs.com>
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On Thu, 16 Nov 2006 12:37:17 +0300
Alex Tomas <alex@clusterfs.com> wrote:

> >>>>> Andrew Morton (AM) writes:
> 
>  AM> What lock protects the fields in struct ext[234]_reserve_window from being
>  AM> concurrently modified by two CPUs?  None, it seems.  Ditto
>  AM> ext[234]_reserve_window_node.  i_mutex will cover it for write(), but not
>  AM> for pageout over a file hole.  If we end up with a zero- or negative-sized
>  AM> window then odd things might happen.
> 
> truncate_mutex?
> 

yes.  hmm.