diff --git a/block_int.h b/block_int.h
index 877e1e5..96ff4cf 100644
--- a/block_int.h
+++ b/block_int.h
@@ -144,6 +144,7 @@
     int encrypted; /* if true, the media is encrypted */
     int valid_key; /* if true, a valid encryption key has been set */
     int sg;        /* if true, the device is a /dev/sg* */
+    int probed;    /* if true, format was probed automatically */
     /* event callback when inserting/removing */
     void (*change_cb)(void *opaque);
     void *change_opaque;