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From: David Disseldorp <ddiss-l3A5Bk7waGM@public.gmane.org>
To: "Pádraig Brady" <P@draigBrady.com>
Cc: Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	samba-technical
	<samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org>,
	"linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: copy chunk preliminary results
Date: Thu, 21 Nov 2013 11:45:41 +0100	[thread overview]
Message-ID: <20131121114541.09f67b3f@plati.site> (raw)
In-Reply-To: <527771DA.1050701-V8g9lnOeT5ydJdNcDFJN0w@public.gmane.org>

On Mon, 04 Nov 2013 10:07:22 +0000
Pádraig 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 right?

It depends on how the SMB server interprets the copy-chunk wire request.
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

  parent reply	other threads:[~2013-11-21 10:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-04  6:30 copy chunk preliminary results Steve French
     [not found] ` <CAH2r5mtoGCn-z_-Aetwaxxvn8bS19mexb7Rur3TE=RGipGCppQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-11-04 10:07   ` Pádraig Brady
     [not found]     ` <527771DA.1050701-V8g9lnOeT5ydJdNcDFJN0w@public.gmane.org>
2013-11-21 10:45       ` David Disseldorp [this message]
     [not found]         ` <20131121114541.09f67b3f-k1XZOR0ctBLN0uC3ymp8PA@public.gmane.org>
2013-11-21 11:20           ` Christoph Hellwig
     [not found]             ` <20131121112044.GA26664-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2013-11-21 11:35               ` Volker Lendecke
2013-11-21 12:31               ` Steve French

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