[Qemu-block] [PATCH v2 1/6] block: Add blocker on mirror target

[Fam Zheng]

In block/backup.c, we already check and add blocker on the target bs,
which is necessary so that it won't be intervened with other operations.

In block/mirror.c we should also protect the mirror target bs, because it
could have a node-name (drive-mirror ... node-name=XXX), and on top of
that it's safe to add blockdev-mirror.

Signed-off-by: Fam Zheng <address@hidden>
---
 block/mirror.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/mirror.c b/block/mirror.c
index 33c640f..0afe585 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -360,6 +360,7 @@ static void mirror_exit(BlockJob *job, void *opaque)
         aio_context_release(replace_aio_context);
     }
     g_free(s->replaces);
+    bdrv_op_unblock_all(s->target, s->common.blocker);
     bdrv_unref(s->target);
     block_job_completed(&s->common, data->ret);
     g_free(data);
@@ -695,6 +696,7 @@ static void mirror_start_job(BlockDriverState *bs, 
BlockDriverState *target,
     if (!s->dirty_bitmap) {
         return;
     }
+    bdrv_op_block_all(target, s->common.blocker);
     bdrv_set_enable_write_cache(s->target, true);
     if (s->target->blk) {
         blk_set_on_error(s->target->blk, on_target_error, on_target_error);
-- 
2.4.3