Re: [Qemu-devel] Closing Bitmaps (Was: Re: [PATCH v7 03/24] block: Release dirty bitmaps in bdrv_close())

From: Kevin Wolf <kwolf@redhat.com>
To: John Snow <jsnow@redhat.com>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	Alberto Garcia <berto@igalia.com>,
	qemu-block@nongnu.org, qemu-devel@nongnu.org,
	Markus Armbruster <armbru@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, Fam Zheng <famz@redhat.com>,
	Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] Closing Bitmaps (Was: Re: [PATCH v7 03/24] block: Release dirty bitmaps in bdrv_close())
Date: Wed, 18 Nov 2015 16:03:34 +0100	[thread overview]
Message-ID: <20151118150334.GF4817@noname.str.redhat.com> (raw)
In-Reply-To: <564B5E4B.4000406@redhat.com>

Am 17.11.2015 um 18:05 hat John Snow geschrieben:
> Still the subject of debate on-list, but the thought is roughly this:
> 
> Bitmaps will be able to flush-to-file on close. (If they have no
> persistence data, it's a no-op (maybe.)) This might mean being flushed
> to their own BDS -- the one they are describing -- as a qcow2 extension.
> Or, it could be to an arbitrary new standalone file format designed for
> the sole purpose of containing bitmap data.
> 
> The discussion hasn't progressed beyond "Max and Kevin do not think
> storing arbitrary bitmaps in .qcow2 files is a good idea." The logical
> conclusion is "We need a new standalone format, then" but we haven't
> decided what that format will look like or how it will be used.

I think the actual logical conclusion is that you use qcow2 images in
order to use the feature.

Kevin