From owner-freebsd-fs@FreeBSD.ORG Mon Sep 8 16:27:09 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 7BB8016A4BF for ; Mon, 8 Sep 2003 16:27:09 -0700 (PDT) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.FreeBSD.org (Postfix) with ESMTP id BF1E243FDD for ; Mon, 8 Sep 2003 16:27:08 -0700 (PDT) (envelope-from bright@elvis.mu.org) Received: by elvis.mu.org (Postfix, from userid 1192) id B12372ED439; Mon, 8 Sep 2003 16:27:08 -0700 (PDT) Date: Mon, 8 Sep 2003 16:27:08 -0700 From: Alfred Perlstein To: Eno Thereska Message-ID: <20030908232708.GE15671@elvis.mu.org> References: <3F5D0663.7020902@andrew.cmu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3F5D0663.7020902@andrew.cmu.edu> User-Agent: Mutt/1.4.1i cc: freebsd-fs@freebsd.org Subject: Re: 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 23:27:09 -0000 * Eno Thereska [030908 15:45] wrote: > 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? afaik, cg by cg is how you'll have to do it. -- - Alfred Perlstein - Research Engineering Development Inc. - email: bright@mu.org cell: 408-480-4684