From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zaphod.cobb.me.uk ([213.138.97.131]:53221 "EHLO zaphod.cobb.me.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758315AbcHCUUz (ORCPT ); Wed, 3 Aug 2016 16:20:55 -0400 Received: from black.home.cobb.me.uk (unknown [192.168.0.205]) by zaphod.cobb.me.uk (Postfix) with ESMTP id 882839B96E for ; Wed, 3 Aug 2016 20:56:01 +0100 (BST) Received: from [192.168.0.211] (novatech.home.cobb.me.uk [192.168.0.211]) by black.home.cobb.me.uk (Postfix) with ESMTPS id 6892B5FBA1 for ; Wed, 3 Aug 2016 20:56:01 +0100 (BST) To: linux-btrfs@vger.kernel.org From: Graham Cobb Subject: Extents for a particular subvolume Message-ID: <57A24C51.2050302@cobb.uk.net> Date: Wed, 3 Aug 2016 20:56:01 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Are there any btrfs commands (or APIs) to allow a script to create a list of all the extents referred to within a particular (mounted) subvolume? And is it a reasonably efficient process (i.e. doesn't involve backrefs and, preferably, doesn't involve following directory trees)? I am not looking to relate the extents to files/inodes/paths. My particular need, at the moment, is to work out how much of two snapshots is shared data, but I can think of other uses for the information. Graham