diff --git a/block/mirror.c b/block/mirror.c
index 5bac906d82fb3c8263adbbcbb8ac0bd1258ac0e3..8d96049555fc2d927a005bb398d006cfdc76013a 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -775,7 +775,7 @@ static void mirror_complete(BlockJob *job, Error **errp)
         }
     }
 
-    /* check the target bs is not blocked and block all operations on it */
+    /* block all operations on to_replace bs */
     if (s->replaces) {
         AioContext *replace_aio_context;