linux-kernel - Re: [patch 01/22] update ctime and mtime for mmaped write

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Message-ID: <45E5EF89.4050707@redhat.com>
Date:	Wed, 28 Feb 2007 16:09:29 -0500
From:	Peter Staubach <staubach@...hat.com>
To:	Miklos Szeredi <miklos@...redi.hu>
CC:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [patch 01/22] update ctime and mtime for mmaped write

Miklos Szeredi wrote:
>> What happens if the application overwrites what it had written some
>> time later?  Nothing.  The page is already read-write, the pte dirty,
>> so even though the file was clearly modified, there's absolutely no
>> way in which this can be used to force an update to the timestamp.
>>     
>
> Which, I realize now, actually means, that the patch is wrong.  Msync
> will have to write protect the page table entries, so that later
> dirtyings may have an effect on the timestamp.

I thought that PeterZ's changes were to write-protect the page after
cleaning it so that future modifications could be detected and tracked
accordingly?  Does the right thing not happen already?

    Thanx...

       ps
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