qemu-img: Convert with copy offloading

The new blk_co_copy_range interface offers a more efficient way in the
case of network based storage. Make use of it to allow faster convert
operation.

Since copy offloading cannot do zero detection ('-S') and compression
(-c), only try it when these options are not used.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20180601092648.24614-11-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
1 file changed