diff --git a/include/block/aio.h b/include/block/aio.h
index 406e32305a..e9aeeaec94 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -454,8 +454,14 @@ static inline void aio_disable_external(AioContext *ctx)
  */
 static inline void aio_enable_external(AioContext *ctx)
 {
-    assert(ctx->external_disable_cnt > 0);
-    atomic_dec(&ctx->external_disable_cnt);
+    int old;
+
+    old = atomic_fetch_dec(&ctx->external_disable_cnt);
+    assert(old > 0);
+    if (old == 1) {
+        /* Kick event loop so it re-arms file descriptors */
+        aio_notify(ctx);
+    }
 }
 
 /**