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	Tue, 30 Oct 2012 11:39:28 -0400
Date: Tue, 30 Oct 2012 15:39:22 +0000
From: Hugo Mills <hugo@carfax.org.uk>
To: =?iso-8859-1?Q?G=E1bor?= Nyers <gnyers@suse.com>
Cc: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: How to find (out if) files sharing content?
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On Tue, Oct 30, 2012 at 04:20:05PM +0100, G=E1bor Nyers wrote:
> Hi,
>=20
> How could one find out if 2 files share any extents on a btrfs file syste=
m?
>=20
> A more generic variation of the above: How to list files on the same
> file system/subvolume sharing content?

   You have direct (read-only) access to the metadata trees through
the TREE_SEARCH ioctl. It should be possible to walk through the
extents of a given file, and (I think) follow back-refs from the
extent back to the other files that share it.

   There's no simple code to do that right now, though.

   Hugo.

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