From: Zheng Liu <gnehzuil.liu@gmail.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [BUG] ext2/3/4: dio reads stale data when we do some append dio writes
Date: Tue, 19 Nov 2013 19:19:47 +0800 [thread overview]
Message-ID: <20131119111947.GA4782@gmail.com> (raw)
In-Reply-To: <20131119110147.GA3323@infradead.org>
On Tue, Nov 19, 2013 at 03:01:47AM -0800, Christoph Hellwig wrote:
> On Tue, Nov 19, 2013 at 06:45:08PM +0800, Zheng Liu wrote:
> > BTW, that would be great if you could give me some comments about this
> > problem itself. Is it a generic problem in vfs? Or just a feature by
> > design?
>
> It seems like a fundamental issue with ext4 (and most older Linux
> filesystems) trying to do dio reads without locking out writers.
Ah, that is a long story for me. Anyway, thanks for your comment.
>
> If you have a shared/exclusive lock to protect dio reads against
> buffered or appending writers like XFS does this issue is properly
> prevented.
Yes, I know that XFS has a shared/exclusive lock. I guess that is why
it can pass the test. But another question is why xfs fails when we do
some append dio writes with doing buffered read.
Regards,
- Zheng
next prev parent reply other threads:[~2013-11-19 11:19 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-19 9:53 [BUG] ext2/3/4: dio reads stale data when we do some append dio writes Zheng Liu
2013-11-19 10:22 ` Christoph Hellwig
2013-11-19 10:45 ` Zheng Liu
2013-11-19 11:01 ` Christoph Hellwig
2013-11-19 11:19 ` Zheng Liu [this message]
2013-11-19 11:18 ` Christoph Hellwig
2013-11-19 11:51 ` Zheng Liu
2013-11-19 11:51 ` Zheng Liu
2013-11-19 12:09 ` Dave Chinner
2013-11-19 12:09 ` Dave Chinner
2013-11-19 12:18 ` Zheng Liu
2013-11-19 12:01 ` Dave Chinner
2013-11-19 12:20 ` Zheng Liu
2013-11-19 12:20 ` Zheng Liu
2013-11-19 10:54 ` Dmitry Monakhov
2013-11-19 11:45 ` Zheng Liu
2013-11-27 23:01 ` Jan Kara
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