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Date: Thu, 10 Jun 2010 17:32:09 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: [Qemu-devel] Re: [PATCH 13/13] blockdev: New -blockdev to define a
 host block device
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To: Markus Armbruster <armbru@redhat.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org, kraxel@redhat.com

On 06/02/2010 06:55 PM, Markus Armbruster wrote:
> * Like -drive, -blockdev ignores cache= silently when snapshot=on.  Do
>    we really want that?

Yes, the changes are throw-away by definition.  Might as well use 
cache=unsafe.

> +    if (snapshot) {
> +        /* always use write-back with snapshot */
> +        /* FIXME ignores explicit cache= *silently*; really want that? */
> +        flags &= ~BDRV_O_CACHE_MASK;
> +        flags |= (BDRV_O_SNAPSHOT | BDRV_O_CACHE_WB);
> +        flags |= BDRV_O_SNAPSHOT;

Cut and paste?

Paolo