diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index ac2a19979ac7ebd6ca87eac58d03d45b6b2397de..2a8e4f50f6701c92d6bc066d35bdbf7fbe3d0b91 100644
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -1072,8 +1072,7 @@ static int mdt_set_info(struct mdt_thread_info *info)
                 RETURN(-EFAULT);
         }
 
-        if (keylen != (sizeof(KEY_READ_ONLY) - 1) ||
-            memcmp(key, KEY_READ_ONLY, keylen) != 0)
+        if (!KEY_IS(KEY_READ_ONLY))
                 RETURN(-EINVAL);
 
         req->rq_status = 0;