From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from p3nlsmtpcp01-01.prod.phx3.secureserver.net ([184.168.200.138]:53003 "EHLO p3nlsmtpcp01-01.prod.phx3.gdg" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753190AbbKLPWt (ORCPT ); Thu, 12 Nov 2015 10:22:49 -0500 Received: from [117.201.18.56] (port=44790 helo=giis.domain.name) by p3plcpnl0639.prod.phx3.secureserver.net with esmtpsa (TLSv1.2:AES128-GCM-SHA256:128) (Exim 4.85) (envelope-from ) id 1ZwtEI-0004F9-M9 for linux-btrfs@vger.kernel.org; Thu, 12 Nov 2015 07:52:03 -0700 Date: Thu, 12 Nov 2015 20:21:58 +0530 From: "Lakshmipathi.G" To: linux-btrfs@vger.kernel.org Subject: understanding csum tree Message-ID: <20151112145158.GA13251@giis.domain.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi - I trying to understand csum tree and its entries. 1) create a filenamed 'ab' with 100KB of data. I can see csum entry for this: item 0 key (EXTENT_CSUM EXTENT_CSUM 4239360) itemoff 3895 itemsize 100 2) created another named 'zb1' with 100KB of data. I can't find csum entry for this.Looks like item-0 is extended with csum of zb1. item 0 key (EXTENT_CSUM EXTENT_CSUM 4239360) itemoff 3795 itemsize 200 If I need to read/print only the csum of 'zb1' file - how to achieve that? thanks! btrfs-debug-tree output : http://pastebin.com/tzKLX2ZU after creating zb1 file : http://pastebin.com/WzjJuzFB Cheers, Lakshmipathi.G