block: Use block_job_add_bdrv() in mirror_start_job()

Use block_job_add_bdrv() instead of blocking all operations in
mirror_start_job() and unblocking them in mirror_exit().
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/mirror.c

@@ -530,7 +530,6 @@ static void mirror_exit(BlockJob *job, void *opaque)
         aio_context_release(replace_aio_context);
     }
     g_free(s->replaces);
-    bdrv_op_unblock_all(target_bs, s->common.blocker);
     blk_unref(s->target);
     s->target = NULL;
     block_job_completed(&s->common, data->ret);
@@ -997,7 +996,7 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
         return;
     }
 
-    bdrv_op_block_all(target, s->common.blocker);
+    block_job_add_bdrv(&s->common, target);
 
     s->common.co = qemu_coroutine_create(mirror_run, s);
     trace_mirror_start(bs, s, s->common.co, opaque);