block: introduce BDRV_REQ_MAY_UNMAP request flag

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Peter Lieven 2013-10-24 12:06:52 +02:00 committed by Kevin Wolf
parent aa7bfbfff7
commit d32f35cbc5
4 changed files with 14 additions and 2 deletions

View file

@ -139,7 +139,7 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs,
if (buffer_is_zero(iov.iov_base, iov.iov_len)) {
ret = bdrv_co_write_zeroes(job->target,
start * BACKUP_SECTORS_PER_CLUSTER,
n, 0);
n, BDRV_REQ_MAY_UNMAP);
} else {
ret = bdrv_co_writev(job->target,
start * BACKUP_SECTORS_PER_CLUSTER, n,