From owner-freebsd-fs@FreeBSD.ORG  Thu Aug 10 00:21:52 2006
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
X-Original-To: freebsd-fs@freebsd.org
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 D7DC416A4DF
	for <freebsd-fs@freebsd.org>; Thu, 10 Aug 2006 00:21:52 +0000 (UTC)
	(envelope-from scottl@samsco.org)
Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 3BE2543D49
	for <freebsd-fs@freebsd.org>; Thu, 10 Aug 2006 00:21:51 +0000 (GMT)
	(envelope-from scottl@samsco.org)
Received: from [192.168.254.11] (phobos.samsco.home [192.168.254.11])
	(authenticated bits=0)
	by pooker.samsco.org (8.13.4/8.13.4) with ESMTP id k7A0LiHA012184;
	Wed, 9 Aug 2006 18:21:50 -0600 (MDT)
	(envelope-from scottl@samsco.org)
Message-ID: <44DA7C18.9050802@samsco.org>
Date: Wed, 09 Aug 2006 18:21:44 -0600
From: Scott Long <scottl@samsco.org>
User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US;
	rv:1.7.13) Gecko/20060414
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: Geeta Khetan <geetakhetan@hotmail.com>
References: <BAY107-F259353F81291142F1B42BCA0550@phx.gbl>
In-Reply-To: <BAY107-F259353F81291142F1B42BCA0550@phx.gbl>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
X-Spam-Status: No, score=-1.4 required=3.8 tests=ALL_TRUSTED autolearn=failed 
	version=3.1.1
X-Spam-Checker-Version: SpamAssassin 3.1.1 (2006-03-10) on pooker.samsco.org
Cc: freebsd-fs@freebsd.org
Subject: Re: bitmap of filesystem
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 10 Aug 2006 00:21:52 -0000

Geeta Khetan wrote:
> 
>   Is there a global bitmap that keeps track of busy/free blocks over the
>   entire file system ? Is there a API or command i can use for that map?
>     Thanks

No, the bitmaps are stored on a per-cylinder group basis.  You can use
cgread() in libufs to read each group and then examine the bitmaps with
the cg* macros in /sys/ufs/ffs/fs.h.

Scott