Re: [Qemu-devel] QEMU online guest disk resize wrt host block devices

[Christoph Hellwig]

On Thu, Sep 01, 2011 at 02:27:55PM +0100, Daniel P. Berrange wrote:
> I see two likely approaches:
> 
>  1. Add a parameter to the existing 'block_resize' command
>     'refreshonly=true|false'
> 
>  2. Add a separate command  'block_refresh'

I think all that you need is a to implement a bdrv_truncate method
for host devices that simply checks if the new size smaller or equal
to the device size, and return 0 in that case or an error otherwise.