Re: [Qemu-devel] [PATCH 3/4] block/vpc: give option to force the current_size field in .bdrv_create

[Peter Lieven]

if the size is forced I would set the chs values to max. this way no new 
creator String is needed and it is even backwards compatible. this is what 
disk2vhd does.

Peter 


> Am 24.02.2016 um 13:24 schrieb Jeff Cody <address@hidden>:
> 
>> On Wed, Feb 24, 2016 at 11:19:37AM +0100, Kevin Wolf wrote:
>> Am 24.02.2016 um 01:47 hat Jeff Cody geschrieben:
>>> When QEMU creates a VHD image, it goes by the original spec,
>>> calculating the current_size based on the nearest CHS geometry (with an
>>> exception for disks > 127GB).
>>> 
>>> Apparently, Azure will only allow images that are sized to the nearest
>>> MB, and the current_size as calculated from CHS cannot guarantee that.
>>> 
>>> Allow QEMU to create images similar to how Hyper-V creates images, by
>>> setting current_size to the specified virtual disk size.  This
>>> introduces an option, force_size, to be passed to the vpc format during
>>> image creation, e.g.:
>>> 
>>>    qemu-img convert -f raw -o force_size -O vpc test.img test.vhd
>>> 
>>> Bug reference: https://bugs.launchpad.net/qemu/+bug/1490611
>>> 
>>> Signed-off-by: Jeff Cody <address@hidden>
>> 
>> We need to set a different creator string here that makes vpc_open()
>> recognise the image as current_size based.
>> 
>> Kevin
> 
> How about "qem2"?  I initially thought about just changing the case on
> "qemu", but I was afraid some other software may treat the app creator
> string as case-insensitive.
> 
> I'll also update patch 1, to recognize that string as well.