diff --git a/storage/maria/ma_blockrec.h b/storage/maria/ma_blockrec.h
index 7262205d10e..cb682eef701 100644
--- a/storage/maria/ma_blockrec.h
+++ b/storage/maria/ma_blockrec.h
@@ -122,6 +122,7 @@ static inline MARIA_RECORD_POS ma_recordpos(pgcache_page_no_t page,
                                             uint dir_entry)
 {
   DBUG_ASSERT(dir_entry <= 255);
+  DBUG_ASSERT(page > 0); /* page 0 is bitmap, not data page */
   return (MARIA_RECORD_POS) (((ulonglong) page << 8) | dir_entry);
 }
 
diff --git a/storage/maria/ma_locking.c b/storage/maria/ma_locking.c
index 2a34d1fe9f3..9d57cd1cba3 100644
--- a/storage/maria/ma_locking.c
+++ b/storage/maria/ma_locking.c
@@ -391,9 +391,15 @@ int _ma_mark_file_changed(MARIA_HA *info)
 {
   uchar buff[3];
   register MARIA_SHARE *share= info->s;
+  int error= 1;
   DBUG_ENTER("_ma_mark_file_changed");
 
-  if (!(share->state.changed & STATE_CHANGED) || ! share->global_changed)
+#define _MA_ALREADY_MARKED_FILE_CHANGED                                 \
+  ((share->state.changed & STATE_CHANGED) && share->global_changed)
+  if (_MA_ALREADY_MARKED_FILE_CHANGED)
+    DBUG_RETURN(0);
+  pthread_mutex_lock(&share->intern_lock); /* recheck under mutex */
+  if (! _MA_ALREADY_MARKED_FILE_CHANGED)
   {
     share->state.changed|=(STATE_CHANGED | STATE_NOT_ANALYZED |
 			   STATE_NOT_OPTIMIZED_KEYS);
@@ -420,7 +426,7 @@ int _ma_mark_file_changed(MARIA_HA *info)
                     sizeof(share->state.header) +
                     MARIA_FILE_OPEN_COUNT_OFFSET,
                     MYF(MY_NABP)))
-        DBUG_RETURN(1);
+        goto err;
     }
     /* Set uuid of file if not yet set (zerofilled file) */
     if (share->base.born_transactional &&
@@ -432,11 +438,15 @@ int _ma_mark_file_changed(MARIA_HA *info)
            _ma_update_state_lsns_sub(share, LSN_IMPOSSIBLE,
                                      trnman_get_min_trid(),
                                      TRUE, TRUE)))
-        DBUG_RETURN(1);
+        goto err;
       share->state.changed|= STATE_NOT_MOVABLE;
     }
   }
-  DBUG_RETURN(0);
+  error= 0;
+err:
+  pthread_mutex_unlock(&share->intern_lock);
+  DBUG_RETURN(error);
+#undef _MA_ALREADY_MARKED_FILE_CHANGED
 }
 
 /*