From owner-freebsd-fs@FreeBSD.ORG Mon Sep 8 15:44:53 2003 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3F2E916A4BF for ; Mon, 8 Sep 2003 15:44:53 -0700 (PDT) Received: from smtp5.andrew.cmu.edu (SMTP5.andrew.cmu.edu [128.2.10.85]) by mx1.FreeBSD.org (Postfix) with ESMTP id 547C343FAF for ; Mon, 8 Sep 2003 15:44:52 -0700 (PDT) (envelope-from eno@andrew.cmu.edu) Received: from andrew.cmu.edu (BLISS.PDL.CMU.EDU [128.2.134.47]) (user=eno mech=PLAIN (0 bits))h88MiouO032001 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NOT) for ; Mon, 8 Sep 2003 18:44:50 -0400 Message-ID: <3F5D0663.7020902@andrew.cmu.edu> Date: Mon, 08 Sep 2003 18:44:51 -0400 From: Eno Thereska User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020529 X-Accept-Language: en-us, en MIME-Version: 1.0 To: freebsd-fs@freebsd.org Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Subject: free block bitmap X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Sep 2003 22:44:53 -0000 Hi, I am using FreeBSD4.4 with FFS as the underlying file system. I need to examine which blocks in the file system are currently in use. These blocks can be metadata or data blocks. I have looked at the FFS code and it seems the only way to get the list of free blocks (or busy blocks) is by querying each cylinder group's (cg) bitmap of free blocks. Is there a global bitmap that keeps track of busy/free blocks over the entire file system or is the only option the cg-by-cg lookup? Thanks a lot Eno