From mboxrd@z Thu Jan  1 00:00:00 1970
From: jim owens <jowens@hp.com>
Subject: Re: [PATCH 1/3] fs: Document the reflink(2) system call.
Date: Tue, 05 May 2009 18:28:49 -0400
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To: Jamie Lokier <jamie@shareable.org>, jim owens <jowens@hp.com>,
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	Theodore Tso <tytso@mit.edu>, linux-fsdevel@vger.kernel.org,
	jmorris@namei.org, oc
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Jamie,

Joel Becker wrote:
> 	"Shares the data extents of the source file".

so with that clarification, do you now agree with this

 > 1) is only for filesystems with COW operation,
 >    if the fs does not support COW it returns ENOSYS.

being a requirement so the user can trust that calling
reflink() uses minimal space (inode/extentmap) and only
a change to the file will trigger a data copy.

jim