From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55907) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g7la2-0003m5-60 for qemu-devel@nongnu.org; Wed, 03 Oct 2018 14:09:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g7la1-0000fv-3a for qemu-devel@nongnu.org; Wed, 03 Oct 2018 14:09:02 -0400 References: <20181003170228.95973-1-vsementsov@virtuozzo.com> From: Eric Blake Message-ID: Date: Wed, 3 Oct 2018 13:08:51 -0500 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/2] nbd server: drop old-style negotiation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladimir Sementsov-Ogievskiy , "qemu-devel@nongnu.org" , "qemu-block@nongnu.org" Cc: "pbonzini@redhat.com" , "mreitz@redhat.com" , "kwolf@redhat.com" , Denis Lunev , "rjones@redhat.com" , "berrange@redhat.com" On 10/3/18 12:59 PM, Vladimir Sementsov-Ogievskiy wrote: > 03.10.2018 20:32, Eric Blake wrote: > On 10/3/18 12:02 PM, Vladimir Sementsov-Ogievskiy wrote: > It's unexpected behavior that without -x option qemu-nbd do old-style > negotiation. Let's use "" as a default name instead (as it is already > done if tls is used) and therefore, drop old-style negotiation from > Qemu NBD server. Hmm, your email quoting style changed from prior emails that used to prepend '>' when quoting, making it harder to tell where the text you are quoting ends,... > > Oddly enough, I wrote a similar patch in parallel, and am only now just seeing your mail. Yours is a bit stronger than mine (I added 'qemu-nbd -O' to allow explicit fallback to oldstyle, while you ripped it out altogether). The client can negotiate either style, so we don't need an option on the client side; rather, this is all about what the server should do by default. > > https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg00568.html > > Does anyone have a preference between the two? Here's the last time it was discussed: > > https://lists.gnu.org/archive/html/qemu-devel/2018-08/msg03252.html > and your reply begins. > Hm, I think everyone who like new-style should answer that he don't care (except stricter way is a bit better: don't have options and code which we don't need). > But if there is someone who has client which support only old-style negotiation his unhappiness (in case of strict way) will outweigh all our "bits":) > > I'm from the first group). But let's chose your patch My argument in favor of your patch over mine: nbdkit is a GREAT testbed for forcing all sorts of integration testing scenarios, including oldstyle servers. Also, it includes a plugin for translating between new and oldstyle at will. That is, if we ever legitimately encounter a client that can only talk oldstyle, but qemu only talks newstyle, we just tell the user to connect: old client => nbdkit -o nbd => newstyle qemu and then qemu doesn't have to worry about oldstyle because nbdkit does instead. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org