Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status

From: Wouter Verhelst <w@uter.be>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: Alex Bligh <alex@alex.org.uk>,
	"nbd-general@lists.sourceforge.net"
	<nbd-general@lists.sourceforge.net>,
	Kevin Wolf <kwolf@redhat.com>, "Denis V . Lunev" <den@openvz.org>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"Stefan stefanha@redhat. com" <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, John Snow <jsnow@redhat.com>
Subject: Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status
Date: Wed, 28 Dec 2016 01:18:55 +0100	[thread overview]
Message-ID: <20161228001855.ukrtvzeictke4ex2@grep.be> (raw)
In-Reply-To: <2812e3e2-983a-42de-a55f-590a87b7fece@virtuozzo.com>

Hi Vladimir,

On Mon, Dec 26, 2016 at 05:52:54PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> Shouldn't we add some flags to REP_META_CONTEXT, for client to be insure, is
> returned string a direct context name or some kind of wildcard? Just a flags
> field, with one flag defined for now: NBD_REP_META_CONTEXT_LEAF and others
> reserved.

I think it should be up to the metadata context namespace definition to
define which syntax represents a direct context name and which
represents a wildcard (if the latter are supported).

A client which doesn't know what a given metadata context implements
can't reasonably ask for information from that context anyway (since
then the client wouldn't know what to do with the returned information),
so it doesn't help much to add a flag here.

-- 
< ron> I mean, the main *practical* problem with C++, is there's like a dozen
       people in the world who think they really understand all of its rules,
       and pretty much all of them are just lying to themselves too.
 -- #debian-devel, OFTC, 2016-02-12