linux-ext4 - Re: [PATCH 11/12] ext4: Make ext4_bio_writepage() handle unprepared buffers

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Message-ID: <20130129015946.GB7003@thunk.org>
Date:	Mon, 28 Jan 2013 20:59:46 -0500
From:	Theodore Ts'o <tytso@....edu>
To:	Jan Kara <jack@...e.cz>
Cc:	linux-ext4@...r.kernel.org
Subject: Re: [PATCH 11/12] ext4: Make ext4_bio_writepage() handle unprepared
 buffers

On Fri, Jan 18, 2013 at 01:00:45PM +0100, Jan Kara wrote:
> So far ext4_bio_writepage() unconditionally cleared dirty bit on all buffers
> underlying the page. That implicitely assumes we can write all buffers. So
> far that is true because callers call into ext4_bio_writepage() make sure
> all buffers in the page are mapped but
> a) it's a data corruption bug waiting to happen
> b) in data=ordered mode when blocksize < pagesize we do need to write pages
>    that may have only some of dirty buffers mapped.
> 
> So change ext4_bio_writepage() to skip buffers that cannot be written without
> clearing their dirty bit.
> 
> Signed-off-by: Jan Kara <jack@...e.cz>

Thanks, applied.

						- Ted
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