From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jan Kara <jack@suse.cz>, "Darrick J. Wong" <djwong@us.ibm.com>,
        Theodore Tso <tytso@mit.edu>, Alexander Viro <viro@zeniv.linux.org.uk>,
        Jens Axboe <axboe@kernel.dk>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Jeff Layton <jlayton@redhat.com>, Dave Chinner <david@fromorbit.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Dave Hansen <dave@linux.vnet.ibm.com>, linux-mm@kvack.org,
        Chris Mason <chris.mason@oracle.com>, Joel Becker <jlbec@evilplan.org>,
        linux-scsi <linux-scsi@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-ext4@vger.kernel.org, Mingming Cao <mcao@us.ibm.com>
Subject: Re: [PATCHSET v3.1 0/7] data integrity: Stabilize pages during writeback for various fses
References: <20110509230318.19566.66202.stgit@elm3c44.beaverton.ibm.com>
	<87tyd31fkc.fsf@devron.myhome.or.jp>
	<20110510133603.GA5823@infradead.org>
	<874o524q9h.fsf@devron.myhome.or.jp>
	<20110510144939.GI4402@quack.suse.cz>
	<87aaeur31x.fsf@devron.myhome.or.jp>
	<20110510170339.GA27538@infradead.org>
Date: Wed, 11 May 2011 05:50:07 +0900
In-Reply-To: <20110510170339.GA27538@infradead.org> (Christoph Hellwig's
	message of "Tue, 10 May 2011 13:03:39 -0400")
Message-ID: <87liyep9fk.fsf@devron.myhome.or.jp>
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Christoph Hellwig <hch@infradead.org> writes:

> On Wed, May 11, 2011 at 12:24:58AM +0900, OGAWA Hirofumi wrote:
>> > under writeback and when it's freed no writeback is started.
>> 
>> Sure for data -> data reallocated case. metadata -> data/metadata is
>> still there.
>
> That's usually handled differently.  For XFS take a look at the
> xfs_alloc_busy_* function.  For 2.6.40 they've been mostly rewritten
> to rarely wait for the reuse but instead avoid busy blocks.  But that's
> a real data integrity issue even without stable pages for I/O.

Sounds good. So... Are you suggesting this series should use better
approach than just blocking?

Thanks.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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