From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from postfix.iai.uni-bonn.de ([131.220.8.4]:61030 "EHLO postfix.iai.uni-bonn.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753407AbaBSNIF (ORCPT ); Wed, 19 Feb 2014 08:08:05 -0500 Received: from [131.220.3.232] (hocheck.informatik.uni-bonn.de [131.220.3.232]) by postfix.iai.uni-bonn.de (Postfix) with ESMTP id 8CBDE5C404 for ; Wed, 19 Feb 2014 13:59:19 +0100 (MET) (envelope-from ochmann@informatik.uni-bonn.de) (envelope-to linux-btrfs@vger.kernel.org) (1) (internal use: ta=1, tu=1, te=1, am=P, au=ochmann) Message-ID: <5304AA69.5020800@informatik.uni-bonn.de> Date: Wed, 19 Feb 2014 13:58:17 +0100 From: Sebastian Ochmann MIME-Version: 1.0 To: linux-btrfs@vger.kernel.org Subject: Meaning of "no_csum" field when scrubbing with -R option Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hello everyone, I have a question: What exactly does the value for "no_csum" mean when doing a scrub with the -R option? Example output: > sudo btrfs scrub start -BR / scrub done for ... ... csum_errors: 0 verify_errors: 0 no_csum: 70517 csum_discards: 87381 super_errors: 0 ... In the btrfs header, I found the following comment for the "no_csum" field of the btrfs_scrub_progress struct: "# of 4k data block for which no csum is present, probably the result of data written with nodatasum" So my question is, why does scrub show a high (i.e. non-zero) value for no_csum? I never enabled nodatasum or a similar option. Best regards Sebastian