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Date: Tue, 24 Apr 2007 10:56:33 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
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Subject: Re: Pagecache: find_or_create_page does not call a proper page
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On Tue, 24 Apr 2007, Andrew Morton wrote:

> > I think that much is also true, but not where the problem lies.
> > Isn't the problem that filesystems using these block devices
> > expect their metadata to be accessible without kmap calls?
> > 
> 
> yup.  wherever we dereference buffer_head.b_data we're touching
> page_address(buffer_head.b_page) without kmapping.

Yes but before we get there we will bounce pagecache pages into an area 
where we do not need kmap.