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From: Christoph Hellwig <hch@infradead.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Jan Kara <jack@suse.cz>, Andreas Dilger <adilger@dilger.ca>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org
Subject: Re: [PATCH] mm: Improve cmtime update on shared writable mmaps
Date: Wed, 2 Nov 2011 03:38:12 -0400	[thread overview]
Message-ID: <20111102073812.GB17580@infradead.org> (raw)
In-Reply-To: <CALCETrW3ZZ=474cXY0HH1=fHTwKJUo--ufPfD1WLpGRC4_CPrw@mail.gmail.com>

On Tue, Nov 01, 2011 at 04:02:24PM -0700, Andy Lutomirski wrote:
> Hmm.  Isn't it permitted to at least read from an fs while holding the
> page lock?  I thought that the page lock was held for the entire
> duration of a read and at the beginning of writeback.
> 
> I can push this down to the ->writepage implementations or to the
> clear_page_dirty_for_io callers, but that will result in a bigger
> patch.

Besides the current way that seems to be the only reasonable place to
do it.  Pushing it into ->writepage also has the benefit that
filesystems could piggy back the ctime update onto the transaction that
updates the extent tree.


  reply	other threads:[~2011-11-02  7:38 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CALCETrWoZeFpznU5Nv=+PvL9QRkTnS4atiGXx0jqZP_E3TJPqw@mail.gmail.com>
2011-10-28 23:39 ` [PATCH] mm: Improve cmtime update on shared writable mmaps Andy Lutomirski
2011-11-01 22:53   ` Jan Kara
2011-11-01 23:02     ` Andy Lutomirski
2011-11-02  7:38       ` Christoph Hellwig [this message]
2011-11-02 15:02       ` Jan Kara
2011-11-02 15:19         ` Ted Ts'o

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