1 files changed, 8 insertions, 0 deletions
diff --git a/innobase/ibuf/ibuf0ibuf.c b/innobase/ibuf/ibuf0ibuf.c
index c07756ab308..7c31ca7c320 100644
--- a/innobase/ibuf/ibuf0ibuf.c
+++ b/innobase/ibuf/ibuf0ibuf.c
@@ -2622,6 +2622,14 @@ loop:
 			goto reset_bit;
 		}
 
+		/* Do NOT merge to the 4.1 code base! */
+		if (trx_sys_downgrading_from_4_1_1) {
+			fprintf(stderr,
+"InnoDB: Fatal error: you are downgrading from >= 4.1.1 to 4.0, but\n"
+"InnoDB: the insert buffer was not empty.\n");
+			ut_a(0);
+		}
+
 		if (corruption_noticed) {
 			rec_sprintf(err_buf, 450, ibuf_rec);