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
