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Date: Fri, 14 Mar 2014 10:20:36 -0400
From: Tejun Heo <tj@kernel.org>
To: Roman Peniaev <r.peniaev@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Jan Kara <jack@suse.cz>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH 1/1] fs/mpage.c: forgotten WRITE_SYNC in case of data
 integrity write
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On Fri, Mar 14, 2014 at 11:17:56PM +0900, Roman Peniaev wrote:
> No, no. Not device does not support flush, filesystem does not care about flush.
> (take any old school, e.g. ext2)
> 
> We did some write, and then we did fsync.
> But filesystem does not support REQ_FLUSH/FUA so block device will never
> get the checkpoint where it should really flush everything.
> 
> So, fsync will not guarantee any integrity in that case.

Oh, no idea.  Fix the filesystem to support REQ_FLUSH?  :)

-- 
tejun