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Date: Thu, 3 Dec 2015 15:53:14 +0100
From: Wouter Verhelst <w@uter.be>
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Subject: Re: [Qemu-devel] [PATCH 00/15] Implement TLS support to QEMU NBD
	server & client
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To: "Daniel P. Berrange" <berrange@redhat.com>
Cc: nbd-general@lists.sourceforge.net, Paolo Bonzini <pbonzini@redhat.com>, qemu-devel@nongnu.org, qemu-block@nongnu.org

Hi all,

On Fri, Nov 27, 2015 at 03:06:51PM +0100, Wouter Verhelst wrote:
> I have been thinking of adding a message NBD_OPT_SELECT_EXPORT to
> replace NBD_OPT_EXPORT_NAME, which would select an export but not end
> negotiation. That would also require another message to end negotiation
> and move on to the transmission phase, obviously.

I've formalized this now, and removed the PEEK_EXPORT extension (which, as you
say, can't be used safely).

> The negotation would then look something like:
> 
> NBD_OPT_SELECT_EXPORT
>  <- NBD_REP_ACK

This has become an NBD_REP_SERVER instead, with (64-bit) export size and
(16-bit) per-export flags appended (rather than yet another flags field).

(the name is also NBD_OPT_SELECT rather than NBD_OPT_SELECT_EXPORT; details)

NBD_OPT_SELECT is 6, NBD_OPT_GO is 7, NBD_REP_ERR_UNKNOWN is 2^31+6.

For more details, see the proto.md document.

Thoughts are welcome.

-- 
It is easy to love a country that is famous for chocolate and beer

  -- Barack Obama, speaking in Brussels, Belgium, 2014-03-26