From owner-freebsd-fs@FreeBSD.ORG  Fri Jun  9 23:45:44 2006
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
X-Original-To: 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 1F44C16A46F
	for <fs@freebsd.org>; Fri,  9 Jun 2006 23:45:44 +0000 (UTC)
	(envelope-from rwatson@FreeBSD.org)
Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 609E443D73
	for <fs@freebsd.org>; Fri,  9 Jun 2006 23:45:42 +0000 (GMT)
	(envelope-from rwatson@FreeBSD.org)
Received: from fledge.watson.org (fledge.watson.org [209.31.154.41])
	by cyrus.watson.org (Postfix) with ESMTP id D499B46CCD;
	Fri,  9 Jun 2006 19:45:41 -0400 (EDT)
Date: Sat, 10 Jun 2006 00:45:41 +0100 (BST)
From: Robert Watson <rwatson@FreeBSD.org>
X-X-Sender: robert@fledge.watson.org
To: Scott Long <scottl@samsco.org>
In-Reply-To: <4489BD63.7060309@samsco.org>
Message-ID: <20060610004447.A26068@fledge.watson.org>
References: <20060609065656.31225.qmail@web30313.mail.mud.yahoo.com>
	<200606091313.04913.mi+mx@aldan.algebra.com>
	<4489ADC9.3090809@samsco.org>
	<200606091330.10007.mi+mx@aldan.algebra.com>
	<4489BD63.7060309@samsco.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Cc: Mikhail Teterin <mi+mx@aldan.algebra.com>, fs@freebsd.org
Subject: Re: Space-saving of UFS1
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: Fri, 09 Jun 2006 23:45:44 -0000


On Fri, 9 Jun 2006, Scott Long wrote:

> The inode size was extended from 128 bytes to 256 bytes to allow for 64-bit 
> block pointers.  This includes 12 direct block pointers and one pointer for 
> each of the single, double, and triple indirect blocks. That didn't fill 
> left some extra space in the 256 bytes, so ACL size info and block pointers 
> were put in there.  However, ACLs are just a side effect of the larger size, 
> not the sole reason.  And, ACLs are not actually stored in the inode, only 
> block pointers to them are.

While the technical statements above are correct, actually, the extended 
attribute storage was the primary motivation for getting UFS2 development 
kicked off.  Since it required rolling the file system layout, we did 64-bit 
support at the same time, dropped back in the birth time, etc.

Robert N M Watson