From owner-freebsd-current@freebsd.org Wed Aug 7 16:01:25 2019 Return-Path: Delivered-To: freebsd-current@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 5BFCFAE4B5 for ; Wed, 7 Aug 2019 16:01:25 +0000 (UTC) (envelope-from mckusick@mckusick.com) Received: from chez.mckusick.com (chez.mckusick.com [70.36.157.235]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 463bpX1N2Fz3NJ6 for ; Wed, 7 Aug 2019 16:01:23 +0000 (UTC) (envelope-from mckusick@mckusick.com) Received: from chez.mckusick.com (localhost [IPv6:::1]) by chez.mckusick.com (8.15.2/8.15.2) with ESMTP id x77GAGDO043785; Wed, 7 Aug 2019 09:10:16 -0700 (PDT) (envelope-from mckusick@mckusick.com) Message-Id: <201908071610.x77GAGDO043785@chez.mckusick.com> From: Kirk McKusick To: "Poul-Henning Kamp" Subject: Re: CURRENT: supeblock hash failure - CURRENT wrecking disks cc: Enji Cooper , "O. Hartmann" , freebsd-current X-URL: http://WWW.McKusick.COM/ Reply-To: Kirk McKusick In-reply-to: <42457.1565182943@critter.freebsd.dk> Comments: In-reply-to "Poul-Henning Kamp" message dated "Wed, 07 Aug 2019 13:02:23 -0000." MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <43783.1565194216.1@chez.mckusick.com> Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00,MISSING_MID, UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on chez.mckusick.com X-Rspamd-Queue-Id: 463bpX1N2Fz3NJ6 X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of mckusick@mckusick.com has no SPF policy when checking 70.36.157.235) smtp.mailfrom=mckusick@mckusick.com X-Spamd-Result: default: False [-1.32 / 15.00]; ARC_NA(0.00)[]; HAS_REPLYTO(0.00)[mckusick@mckusick.com]; REPLYTO_EQ_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; NEURAL_HAM_MEDIUM(-0.62)[-0.617,0]; NEURAL_HAM_LONG(-0.79)[-0.786,0]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[mckusick.com]; AUTH_NA(1.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; NEURAL_HAM_SHORT(-0.71)[-0.706,0]; R_SPF_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:46375, ipnet:70.36.128.0/19, country:US]; FREEMAIL_CC(0.00)[gmail.com]; IP_SCORE(-0.11)[ip: (0.09), ipnet: 70.36.128.0/19(0.05), asn: 46375(-0.66), country: US(-0.05)]; RCVD_COUNT_TWO(0.00)[2] X-Mailman-Approved-At: Sun, 13 Oct 2019 15:23:46 +0000 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Date: Wed, 07 Aug 2019 16:01:25 -0000 X-Original-Date: Wed, 07 Aug 2019 09:10:16 -0700 X-List-Received-Date: Wed, 07 Aug 2019 16:01:25 -0000 > To: Enji Cooper > cc: "O. Hartmann" , > freebsd-current , mckusick@mckusick= .com > Subject: Re: CURRENT: supeblock hash failure - CURRENT wrecking disks > From: "Poul-Henning Kamp" > -------- > In message <39FB31E6-A8EC-484C-B297-39C19A787E44@gmail.com>, Enji Cooper= writes > : > = > There is an "interesting" failure-mechanism when you move a disk > between 13/current and older systems which do not support ufs-hashes. > = > It will be prudent to make 11 and 12 clear the "use hashes" flags > in the superblocks of all filesystems they mount R/W, to limit > the amount havoc this will cause when people start playing with 13. > = > -- = > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe = > Never attribute to malice what can adequately be explained by incompeten= ce. Both stable-11 and stable-12 clear the "use hashes" flags. If the disk is moved back to a 13-head system they remain disabled until reenabled by running fsck in interactive mode and requesting that they be enabled. Kirk McKusick