read_ahead
diff --git a/src/core/ngx_open_file_cache.h b/src/core/ngx_open_file_cache.h
index f059d6b..f56dfcc 100644
--- a/src/core/ngx_open_file_cache.h
+++ b/src/core/ngx_open_file_cache.h
@@ -21,6 +21,7 @@
     time_t                   mtime;
     off_t                    size;
     off_t                    directio;
+    size_t                   read_ahead;
 
     ngx_err_t                err;
     char                    *failed;