From owner-freebsd-hackers@FreeBSD.ORG Tue Apr 25 15:48:03 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D599716A439 for ; Tue, 25 Apr 2006 15:48:03 +0000 (UTC) (envelope-from haro@h4.dion.ne.jp) Received: from smtp1.dcns.ne.jp (smtp1.dcns.ne.jp [203.178.100.134]) by mx1.FreeBSD.org (Postfix) with SMTP id 5F64543D8A for ; Tue, 25 Apr 2006 15:47:50 +0000 (GMT) (envelope-from haro@h4.dion.ne.jp) Received: (qmail 381 invoked from network); 26 Apr 2006 00:47:49 +0900 Received: from unknown (HELO localhost) (211.10.184.118) by smtp1.dcns.ne.jp with SMTP; 26 Apr 2006 00:47:49 +0900 Date: Wed, 26 Apr 2006 00:45:55 +0900 (JST) Message-Id: <20060426.004555.21603794.haro@h4.dion.ne.jp> To: daichi@freebsd.org From: Munehiro Matsuda In-Reply-To: <444E13BA.8050902@freebsd.org> References: <4417DD8D.3050201@freebsd.org> <4433CA53.5050000@freebsd.org> <444E13BA.8050902@freebsd.org> X-Mailer: Mew version 3.3 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: ozawa@ongs.co.jp, freebsd-hackers@freebsd.org, freebsd-fs@freebsd.org, freebsd-current@freebsd.org, Alexander@Leidinger.net, saturnero@freesbie.org Subject: Re: [ANN] unionfs patchset-11 release X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Apr 2006 15:48:03 -0000 Hi Goto-san, From: Daichi GOTO Date: Tue, 25 Apr 2006 21:19:06 +0900 ::It is my pleasure and honor to announce the availability of ::the unionfs patchset-11. :: Heads Up: Above English text contains some Japanese text. :: If you are interested in translating the Japanese :: text into English, please do it and send it to me. How about this? =-------------------------------------------------------------------------- On creating a hardlink, due to VOP_GETWRITEMOUNT() called right after lookup(), if only files exist in the underlying filesystem, VOP_GETWRITEMOUNT() cannot be process on the vnode for the layer above. Thus creating hardlink fails. A complete fix is to change VOP_GETWRITEMOUNT() to create a shadowfile, but its not possible due to the fact that, locking status of vnode passed as argument to VOP_GETWRITEMOUNT() is not stable. In the current kernel code base, filesystems using vop_stdgetwritemount() simply aquire mount point vnode, thus using vnode for directory above seems to suffice and used for the current implementation. But this logic cannot be considered safe and may cause problems in the future. Also, when mounting a directory containing multiple mount points using unionfs, becomes evil. Thus, it is dangerous to mount directories containing multiple mount points, using the current implementation of unionfs. =-------------------------------------------------------------------------- Hope this helps, Haro =------------------------------------------------------------------------------ _ _ Munehiro (haro) Matsuda -|- /_\ |_|_| Internet Solution Dept., KGT Inc. /|\ |_| |_|_| 2-8-8 Shinjuku Shinjuku-ku Tokyo 160-0022, Japan Tel: +81-3-3225-0767 Fax: +81-3-3225-0740 Email: haro-at-kgt.co.jp