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Date:   Thu, 25 Oct 2018 12:07:39 -0400
To:     Olga Kornievskaia <olga.kornievskaia@gmail.com>
Cc:     bfields@redhat.com, linux-nfs@vger.kernel.org
Subject: Re: [PATCH v1 00/13] server-side support for "inter" SSC copy
Message-ID: <20181025160739.GC5539@fieldses.org>
References: <20181019152905.32418-1-olga.kornievskaia@gmail.com>
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From:   bfields@fieldses.org (J. Bruce Fields)
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On Fri, Oct 19, 2018 at 11:28:52AM -0400, Olga Kornievskaia wrote:
> This patch series adds support for NFSv4.2 copy offload feature
> allowing copy between two different NFS servers.

Apologies, it may take me another week or so to get to this....

This is the part that sounds trickiest!:

> On the destination server, upon receiving a COPY request, the server
> establishes the necessary clientid/session with the source server.
> It calls into the NFS client code to establish the necessary
> open stateid, filehandle, file description (without doing an NFS open).
> Then the server calls into the copy_file_range() to preform the copy
> where the source file will issue NFS READs and then do local file
> system writes (this depends on the VFS ability to do cross device
> copy_file_range().

--b.