From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:34023 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751085AbbBEKkV (ORCPT ); Thu, 5 Feb 2015 05:40:21 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1YJJr9-0000P7-50 for linux-btrfs@vger.kernel.org; Thu, 05 Feb 2015 11:40:19 +0100 Received: from barriere.frankfurter-softwarefabrik.de ([217.11.197.1]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 05 Feb 2015 11:40:19 +0100 Received: from lvml by barriere.frankfurter-softwarefabrik.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 05 Feb 2015 11:40:19 +0100 To: linux-btrfs@vger.kernel.org From: Lutz Vieweg Subject: Can I get a checksum for a file from btrfs (without reading the whole file)? Date: Thu, 05 Feb 2015 11:40:10 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hi, use case: You have two huge files on a btrfs, you assume they contain the same bytes, but you do not know for sure. Is there a way to get a checksum of both files from btrfs with less effort than reading the whole of both files and computing a hash sum? (I was thinking that the btrfs-internal CRCs might be of use, here...) Regards, Lutz Vieweg