From owner-freebsd-stable Wed Jul 26 14:26:27 2000 Delivered-To: freebsd-stable@freebsd.org Received: from mail.gmx.net (pop.gmx.net [194.221.183.20]) by hub.freebsd.org (Postfix) with SMTP id F0B2E37BEB6 for ; Wed, 26 Jul 2000 14:26:21 -0700 (PDT) (envelope-from Gerhard.Sittig@gmx.net) Received: (qmail 28180 invoked by uid 0); 26 Jul 2000 21:26:19 -0000 Received: from p3ee0b80b.dip.t-dialin.net (HELO speedy.gsinet) (62.224.184.11) by mail.gmx.net with SMTP; 26 Jul 2000 21:26:19 -0000 Received: (from sittig@localhost) by speedy.gsinet (8.8.8/8.8.8) id VAA27883 for stable@FreeBSD.ORG; Wed, 26 Jul 2000 21:44:01 +0200 Date: Wed, 26 Jul 2000 21:44:01 +0200 From: Gerhard Sittig To: stable@FreeBSD.ORG Subject: Re: URGENT: bad superblock Message-ID: <20000726214401.K24476@speedy.gsinet> Mail-Followup-To: stable@FreeBSD.ORG References: <4.3.2.7.2.20000726110451.02e6ef00@msm.cl> <20000726172005.A79537@chuggalug.clues.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <20000726172005.A79537@chuggalug.clues.com>; from geoffb@chuggalug.clues.com on Wed, Jul 26, 2000 at 05:20:05PM +0100 Organization: System Defenestrators Inc. Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, Jul 26, 2000 at 17:20 +0100, Geoff Buckingham wrote: > On Wed, Jul 26, 2000 at 11:13:05AM -0400, Marcelo J. Iturbe wrote: > > > > Running FreeBSD 3.3 I have the following scenario: > > The filesystem won't boot. > > When I try to mount (/dev/da0s2) it from an emergency boot disk I get a > > "Incorrect Superblock" error. > > When I try to run fsck it gives me an error about wrong magic number. > > Here is the partition information > > What kind of file system is this? (ie ffs or FAT16/32) > If it is ufs/ffs are you specifying a partition as well as a slice? > > example command line>mount /dev/da0s2a /mnt Which turns out to be a little hard sometimes (been there with the 4.0 CD set this week) when the fixit media doesn't have slice entries in /dev and you don't have access to the (yet to be mounted!) filesystem with the appropriate /dev entries. Funnily ad0s1 happily gets mounted when it regularly should be ad0s1a, later I found that the minor numbers are the same for them. But the fixit prompts never would let me access slices other than *a. And it took quite some time to find the minors' numbering (I finally found it when reading disklabel(5) for completely other reasons). Once this is known you can mknod(8) whatever you need at the fixit prompt. Returning to the problem: From L*'s ext2fs I know of a method to fallback to the superblock's copies sprinkled all over the disk (every 8192 blocks?) when the "first" one is damaged. This info could at least be used to restore the first one to make mount work again. Is there some similar mechanism for ffs/ufs? virtually yours 82D1 9B9C 01DC 4FB4 D7B4 61BE 3F49 4F77 72DE DA76 Gerhard Sittig true | mail -s "get gpg key" Gerhard.Sittig@gmx.net -- If you don't understand or are scared by any of the above ask your parents or an adult to help you. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message