1 files changed, 1 insertions, 0 deletions
diff --git a/block_int.h b/block_int.h
index 6ebdc3eea2..545ad11ff3 100644
--- a/block_int.h
+++ b/block_int.h
@@ -199,6 +199,7 @@ struct BlockDriverState {
     char device_name[32];
     unsigned long *dirty_bitmap;
     int64_t dirty_count;
+    int in_use; /* users other than guest access, eg. block migration */
     QTAILQ_ENTRY(BlockDriverState) list;
     void *private;
 };