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From: Dave Chinner <david@fromorbit.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
	xfs <linux-xfs@vger.kernel.org>,
	Ilya Dryomov <idryomov@gmail.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Brian Foster <bfoster@redhat.com>,
	holger@applied-asynchrony.com,
	linux-ext4 <linux-ext4@vger.kernel.org>,
	linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH v2] iomap: report collisions between directio and buffered writes to userspace
Date: Tue, 21 Nov 2017 07:26:06 +1100	[thread overview]
Message-ID: <20171120202606.GN5858@dastard> (raw)
In-Reply-To: <20171120161829.GA25991@bombadil.infradead.org>

On Mon, Nov 20, 2017 at 08:18:29AM -0800, Matthew Wilcox wrote:
> On Fri, Nov 17, 2017 at 11:39:25AM -0800, Darrick J. Wong wrote:
> > If two programs simultaneously try to write to the same part of a file
> > via direct IO and buffered IO, there's a chance that the post-diowrite
> > pagecache invalidation will fail on the dirty page.  When this happens,
> > the dio write succeeded, which means that the page cache is no longer
> > coherent with the disk!
> 
> This seems like a good opportunity to talk about what I've been working
> on for solving this problem.  The XArray is going to introduce a set
> of entries which can be stored to locations in the page cache that I'm
> calling 'wait entries'.

What's this XArray thing you speak of?

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  reply	other threads:[~2017-11-20 20:26 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-17 19:39 [PATCH v2] iomap: report collisions between directio and buffered writes to userspace Darrick J. Wong
2017-11-17 22:56 ` Liu Bo
2017-11-20 16:18 ` Matthew Wilcox
2017-11-20 20:26   ` Dave Chinner [this message]
2017-11-20 21:51     ` Matthew Wilcox
2017-11-20 22:27       ` Dave Chinner
2017-11-21  1:37         ` Darrick J. Wong
2017-11-21  4:32           ` Matthew Wilcox
2017-11-21  6:48             ` Dave Chinner
2017-11-21 12:52               ` Matthew Wilcox
2017-11-21 22:28                 ` Dave Chinner
2017-11-22  0:05                   ` Darrick J. Wong
2017-11-21 17:23         ` Matthew Wilcox
2017-11-21 18:53           ` Darrick J. Wong

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