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From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Qu Wenruo <quwenruo@cn.fujitsu.com>,
	linux-xfs@vger.kernel.org, fstests@vger.kernel.org,
	btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: About difference in extent sharing in btrfs and xfs
Date: Tue, 15 Nov 2016 00:55:26 -0800	[thread overview]
Message-ID: <20161115085526.GA18347@infradead.org> (raw)
In-Reply-To: <20161115074715.GA23680@birch.djwong.org>

On Mon, Nov 14, 2016 at 11:47:15PM -0800, Darrick J. Wong wrote:
> XFS doesn't split the extent either, internally.  The FIEMAP
> implementation cross-references extent data with the refcount records,
> using extra struct fiemap_extent to report precisely which blocks are
> shared and which aren't.  ocfs2 exhibits the same behavior.

And I think exact reporting of already shared extents in FIEMAP is
extremely important - independent of the internal implementation btrfs
should report the extents correctly.

      parent reply	other threads:[~2016-11-15  8:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-15  6:33 About difference in extent sharing in btrfs and xfs Qu Wenruo
2016-11-15  7:47 ` Darrick J. Wong
2016-11-15  7:53   ` Qu Wenruo
2016-11-15  8:55   ` Christoph Hellwig [this message]

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