From owner-freebsd-fs@freebsd.org Sun Oct 29 11:25:42 2017 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 25FBAE60DA9 for ; Sun, 29 Oct 2017 11:25:42 +0000 (UTC) (envelope-from se@freebsd.org) Received: from mailout09.t-online.de (mailout09.t-online.de [194.25.134.84]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mailout00.t-online.de", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id DDCDD7617C; Sun, 29 Oct 2017 11:25:41 +0000 (UTC) (envelope-from se@freebsd.org) Received: from fwd23.aul.t-online.de (fwd23.aul.t-online.de [172.20.26.128]) by mailout09.t-online.de (Postfix) with SMTP id E3A9E42756C3; Sun, 29 Oct 2017 12:25:38 +0100 (CET) Received: from Stefans-MBP-2.fritz.box (Tl8UDeZLZhJZL9qtz0Pg5UelmE0NCMwW5qt0qkJpgBZ1eePsHbihDwGImqto2uggD3@[84.154.121.171]) by fwd23.t-online.de with (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384 encrypted) esmtp id 1e8lij-28eAim0; Sun, 29 Oct 2017 12:25:37 +0100 Subject: Re: softdep as a mount(8) option To: Kirk McKusick , Mark Johnston Cc: freebsd-fs@FreeBSD.org References: <201710282225.v9SMPDCZ074228@chez.mckusick.com> From: Stefan Esser Message-ID: <659abe72-69f9-8e89-24ba-36a9fdfb3fd5@freebsd.org> Date: Sun, 29 Oct 2017 12:25:37 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <201710282225.v9SMPDCZ074228@chez.mckusick.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-GB Content-Transfer-Encoding: 7bit X-ID: Tl8UDeZLZhJZL9qtz0Pg5UelmE0NCMwW5qt0qkJpgBZ1eePsHbihDwGImqto2uggD3 X-TOI-MSGID: 2e3bb460-f905-4a04-a334-b2271149dcd6 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 29 Oct 2017 11:25:42 -0000 Am 29.10.17 um 00:25 schrieb Kirk McKusick: >> Date: Fri, 27 Oct 2017 11:39:00 -0400 >> From: Mark Johnston >> To: freebsd-fs@FreeBSD.org >> Subject: softdep as a mount(8) option >> >> Hi, >> >> I'd like to finally enable the use of SU (not SU+J) on some small UFS >> filesystems. The fact that SU is enabled using a flag in the superblock >> poses a problem for me, however: the systems containing these >> filesystems may at any time be repurposed to run a kernel that supports >> SU but contains bugs[*] that render it unusable. I therefore can't >> persistently enable SU in these systems. >> >> I'm wondering if it would be possible to enable SU using a mount >> option rather than with a persistent flag. fsck_ffs conditionalizes some >> of its logic on whether SU is configured - is this necessary for >> correctness? That is, if I run fsck on an unclean filesystem that had >> been mounted with SU, and fsck runs as though SU hadn't been configured, >> what problems might arise? >> >> [*] These bugs are a result of local modifications and aren't in >> FreeBSD. > > While it is safe and possible to add soft-updates (but not journalled > soft updates) as a mount option, it means that fsck will not know that > soft updates were in use, so it will always run in full (slow) mode at > boot time. This is why I have not added it as an option. Hi Kirk, this is a link to the message where you agreed to make SU a mount option: http://docs.freebsd.org/cgi/mid.cgi?200006282051.NAA05776 Seems you were (rightly) not too worried about FSCK, back then ;-) Regards, STefan