diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index a7a9a63..15615ca 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -192,6 +192,8 @@
     ngx_table_elt_t                *content_encoding;
 #endif
 
+    off_t                           content_length_n;
+
     ngx_array_t                     cache_control;
 } ngx_http_upstream_headers_in_t;