[Qemu-devel] [PATCH 09/12] block: Add "drained begin/end" for transactional blockdev-backup

[Fam Zheng <famz@redhat.com>]

Similar to the previous patch, make sure that external events are not
dispatched during transaction operations.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 blockdev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/blockdev.c b/blockdev.c
index 232bc21..015afbf 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1680,6 +1680,8 @@ static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
         return;
     }
     aio_context_acquire(state->aio_context);
+    state->bs = bs;
+    bdrv_drained_begin(bs);
 
     qmp_blockdev_backup(backup->device, backup->target,
                         backup->sync,
@@ -1692,7 +1694,6 @@ static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
         return;
     }
 
-    state->bs = bs;
     state->job = state->bs->job;
 }
 
@@ -1712,6 +1713,7 @@ static void blockdev_backup_clean(BlkTransactionState *common)
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
 
     if (state->aio_context) {
+        bdrv_drained_end(state->bs);
         aio_context_release(state->aio_context);
     }
 }
-- 
2.5.3