From owner-freebsd-questions Wed Mar 15 3:47:11 2000 Delivered-To: freebsd-questions@freebsd.org Received: from implode.root.com (root.com [209.102.106.178]) by hub.freebsd.org (Postfix) with ESMTP id DD6D937B9B7 for ; Wed, 15 Mar 2000 03:47:09 -0800 (PST) (envelope-from dg@implode.root.com) Received: from implode.root.com (localhost [127.0.0.1]) by implode.root.com (8.8.8/8.8.5) with ESMTP id DAA07398; Wed, 15 Mar 2000 03:41:17 -0800 (PST) Message-Id: <200003151141.DAA07398@implode.root.com> To: "Lin Gu" Cc: freebsd-questions@FreeBSD.ORG Subject: Re: cannot hard link point to directory? In-reply-to: Your message of "Wed, 15 Mar 2000 17:10:25 +0800." <08da01bf8e5e$5f770990$19b769a2@shawshank> From: David Greenman Reply-To: dg@root.com Date: Wed, 15 Mar 2000 03:41:17 -0800 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >I'm confused why hard link cannot point to directory. It can just point to >the inode of the directory file, i suppose. ...a completely different question than the problems that were being discussed, but I'll try to answer. The problem with hard directory links is that there isn't any [easy/inexpensive] way to detect filesystem recursion (i.e. when a link points upward in the path). Also, due to characteristics of the FFS filesystem, the system really wants to have only one parent directory pointer (especially the case in crash recovery); a directory hard link makes that not the case any longer. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project - http://www.freebsd.org Creator of high-performance Internet servers - http://www.terasolutions.com Pave the road of life with opportunities. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message