Date: Fri, 5 May 2006 19:21:48 -0700
From: Andrew Morton <akpm@osdl.org>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: shaggy@austin.ibm.com, dhowells@redhat.com, phillip@hellewell.homeip.net,
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       jmorris@namei.org, sct@redhat.com, ezk@cs.sunysb.edu
Subject: Re: [PATCH 10/13: eCryptfs] Mmap operations
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On Fri, 05 May 2006 18:38:48 +0300
Pekka Enberg <penberg@cs.helsinki.fi> wrote:

> On Thu, 2006-05-04 at 22:43 +0100, David Howells wrote:
> > > When writing CacheFiles, I noticed that ext3 would occasionally unlock a page
> > > that had neither PG_uptodate nor PG_error set, and so I had to force another
> > > readpage() on it.
> 
> On Fri, 2006-05-05 at 10:22 -0500, Dave Kleikamp wrote:
> > I understand this comes from the FiST package.  In that code, there is a
> > comment in one of these functions explaining the second read.  It would
> > be nice to have that comment in here too:
> > 
> >    /*
> >     * call readpage() again if we returned from wait_on_page with a
> >     * page that's not up-to-date; that can happen when a partial
> >     * page has a few buffers which are ok, but not the whole
> >     * page.
> >     */
> > 
> > I'm a bit surprised that this could happen.
> 
> Me too. How do we know we don't end up the same way for the second read?
> 

And why doesn't it cause do_generic_mapping_read() and page_cache_read() to
fail?

This is all raher fishy.
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