Re: migration: broken snapshot saves appear on s390 when small fields in migration stream removed

[Paolo Bonzini]

On 28/07/20 13:45, Max Reitz wrote:
>> Is it possible to make a quick testcase using qemu-io?
> This seems to work:
> 
> $ qemu-img create -f qcow2 -o cluster_size=512 base.qcow2 512
> $ qemu-img create -f qcow2 -o cluster_size=512 -F qcow2 -b base.qcow2 \
>   top.qcow2 1024
> $ qemu-io -c 'write -P 42 0 512' top.qcow2
> $ qemu-io -c 'read -v 0 1024' top.qcow2
> 
> That should print 512 times “2a” and then 512 times “00”, but beyond
> 512, the buffer stays uninitialized; instead, the first 512 bytes are
> zeroed.  (With the patch, it works as expected.)
> 

Wow, that's great (and a good recipe for qemu-iotests too).  Thanks.

Paolo