Re: [Qemu-devel] [PATCH RESEND] Support vhd type VHD_DIFFERENCING

[Xiaodong Gong]

On Wed, Nov 26, 2014 at 11:57 PM, Stefan Hajnoczi <address@hidden> wrote:

On Thu, Nov 06, 2014 at 10:43:50PM +0800, Xiaodong Gong wrote:
> Now qemu only supports vhd type VHD_FIXED and VHD_DYNAMIC, so qemu
> can't read snapshot volume of vhd, and can't support other storage
> features of vhd file.
>
> This patch add read parent information in function "vpc_open", read
> bitmap in "vpc_read", and change bitmap in "vpc_write".
>
> Signed-off-by: Xiaodong Gong <address@hidden>
> Reviewed-by: Ding xiao <address@hidden>
> ---

Have you run tests/qemu-iotests/check for all 3 subformats (fixed,
dynamic, and differencing)?

http://qemu-project.org/Documentation/QemuIoTests

The tests need to pass before we can merge a new subforma

There are 004, 006, 099 and 104 of test case that do not be passed, the same 

as the current master branch. 

004 to sure that writing/reading offset after size of image fails, but not.

006 to sure that creating a > 128G image fails, but not.

099 to sure that parsing args of qemu --drive is robust. 

104 to sure that real size of image is 1024 for 1024, 1536 for 1025(not 1024 align), but all is 34816

And qemu-img could not create the snapshot of vpc,  so _make_test_img is not works with args of '-b'.  vhd_differencing format cloud not be tested with qemu-iostest now.