Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/21/2010 10:00 AM, Christoph Hellwig wrote:
> Keeping these separate makes a lot of sense to me, even with my user
> hat on.  And as lon as we don't require the transport protocol but fall
> back to file it's even more understandable for the users, as he simply
> doesn't have to care about it for the 99% case.  Now for the image
> format specifying it usually is a good thing as the autodetecting could
> easily get into trouble when the guest creates say a full-device qcow2
> image in a device that's an image file on the host.
>    

I agree that transport makes a lot more sense.

There's just a couple cases we should consider:

[1] -blockdev format=raw,file=/dev/cdrom,id=blk1

[2] -blockdev format=vvfat,file=/path/to/directory,id=blk1

For [1], we just defaulting transport to file is would not give us the 
same semantics we have today.  Is that desirable?

It's not clear to me why [2] should be transport=vvfat.  vvfat really 
isn't a transport.  What about things like blkdebug and if we had 
something like a ramdisk?

Regards,

Anthony Liguori