use ngx_ext_rename_file() for single file MOVE
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 840007f..ae56c12 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -2288,9 +2288,11 @@
     }
 
     ext.access = u->conf->store_access;
+    ext.path_access = u->conf->store_access;
     ext.time = -1;
     ext.create_path = 1;
     ext.delete_file = 1;
+    ext.log_rename_error = 1;
     ext.log = r->connection->log;
 
     if (u->headers_in.last_modified) {