tree af8a045ab17230ead191ffba9886025c6b12a35e
parent 0fc9f8ea2800b76eaea20a8a3a91fbeeb4bfa81b
author Fam Zheng <famz@redhat.com> 1433742969 +0800
committer Stefan Hajnoczi <stefanha@redhat.com> 1435827983 +0100

mirror: Do zero write on target if sectors not allocated

If guest discards a source cluster, mirroring with bdrv_aio_readv is overkill.
Some protocols do zero upon discard, where it's best to use
bdrv_aio_write_zeroes, otherwise, bdrv_aio_discard will be enough.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>