From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Disseldorp <ddiss-l3A5Bk7waGM@public.gmane.org>
Subject: Re: copy chunk preliminary results
Date: Thu, 21 Nov 2013 11:45:41 +0100
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On Mon, 04 Nov 2013 10:07:22 +0000
P=C3=A1draig Brady <P@draigBrady.com> wrote:

> So cp --reflink has CoW semantics and so probably not an
> appropriate interface for this.  Unless I'm misunderstanding,
> this SMB copy offload does result in a normal copy on the server righ=
t?

It depends on how the SMB server interprets the copy-chunk wire request=
=2E
On Btrfs, Samba can translate the request into a BTRFS_IOC_CLONE_RANGE
ioctl, in which case the same CoW semantics are observed[1]. See:

https://wiki.samba.org/index.php/Server-Side_Copy#Btrfs_Enhanced_Server=
-Side_Copy_Offload

By default however, Samba (and Windows) will perform the copy on the
server-side using regular reads/writes. A generic cp --offload or
similar would probably make more sense on the client side.

Cheers, David