From owner-freebsd-bugs@FreeBSD.ORG Fri Nov 11 19:01:16 2005 Return-Path: X-Original-To: freebsd-bugs@freebsd.org Delivered-To: freebsd-bugs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7AD2016A41F for ; Fri, 11 Nov 2005 19:01:16 +0000 (GMT) (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 3332E43D45 for ; Fri, 11 Nov 2005 19:01:16 +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 B85DC46B90; Fri, 11 Nov 2005 14:01:15 -0500 (EST) Date: Fri, 11 Nov 2005 19:01:15 +0000 (GMT) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: John Kozubik In-Reply-To: <20051111091807.J95949@kozubik.com> Message-ID: <20051111185927.Q33260@fledge.watson.org> References: <20051111091807.J95949@kozubik.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-bugs@freebsd.org Subject: Re: mounted snapshots still writeable 1.5 years later (RE: kern/68576) X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Nov 2005 19:01:16 -0000 On Fri, 11 Nov 2005, John Kozubik wrote: > In July of 2004 (circa 5.2.1-RELEASE) I filed kern/68576 which described > how snapshot files can be mounted read/write and altered. New files can > be added to them, existing files can be deleted or altered, and the > snapshot file can be returned to read-only state and still be used. > > It was generally agreed that this was a bad thing - it is unexpected > behavior that contradicts the technical requirements of UFS2 snapshots > as well as the behavior that the FreeBSD documentation provides. It is > also potentially dangerous. > > It is now Nov. 2005, circa 5.4-RELEASE, and the behavior described in > this PR has not changed. Could you try it on 6.x? There have been a number of changes relating to writable mounting and md devices in 6.x in order to correct related problems, and my understand was they should also fix this one. FYI, locally, I get: peppercorn# mdconfig -a -t vnode -f test WARNING: opening backing store: /mnt/.snap/test readonly md1 peppercorn# mount /dev/md1 /mnt2 mount: /dev/md1: Read-only file system peppercorn# mount -o rdonly /dev/md1 /mnt2 peppercorn# ls -l total 2 drwxrwxr-x 2 root operator 512 Nov 11 18:56 .snap peppercorn# mount -uw /mnt2 mount: /dev/md1: Read-only file system Robert N M Watson