From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-bk0-f53.google.com ([209.85.214.53]:50550 "EHLO mail-bk0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753067Ab3AFRUc (ORCPT ); Sun, 6 Jan 2013 12:20:32 -0500 Received: by mail-bk0-f53.google.com with SMTP id j5so8025740bkw.12 for ; Sun, 06 Jan 2013 09:20:31 -0800 (PST) Message-ID: <50E9B26D.3030900@gmail.com> Date: Sun, 06 Jan 2013 18:20:45 +0100 From: Goffredo Baroncelli Reply-To: kreijack@inwind.it MIME-Version: 1.0 CC: Chris Murphy , "linux-btrfs@vger.kernel.org list" Subject: Re: BUG btrfs fi show displays stale btrfs volume References: <96FA5245-87A9-43C4-9B56-C0F4ADB9D975@colorremedies.com> <50E9A5D1.4050704@inwind.it> In-Reply-To: <50E9A5D1.4050704@inwind.it> Content-Type: text/plain; charset=ISO-8859-1 To: unlisted-recipients:; (no To-header on input) Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 01/06/2013 05:26 PM, Goffredo Baroncelli wrote: > Hi Chris [...] > > I will start to update the wiki; then I will give a look to wipefs to > improve it. Hello I updated the wiki page: https://btrfs.wiki.kernel.org/index.php/Problem_FAQ#What_if_I_don.27t_have_wipefs_at_hand.3F ----- What if I don't have wipefs at hand? There are three superblocks: the first one is located at 64K, the second one at 64M, the third one at 256GB. The following lines reset the magic string on all the three superblocks # dd if=/dev/zero bs=1 count=8 of=/dev/sda seek=$((64*1024+64)) # dd if=/dev/zero bs=1 count=8 of=/dev/sda seek=$((64*1024*1024+64)) # dd if=/dev/zero bs=1 count=8 of=/dev/sda seek=$((256*1024*1024*1024+64)) If you want to restore the superblocks magic string, # echo "_BHRfS_M" | dd bs=1 count=8 of=/dev/sda seek=$((64*1024+64)) # echo "_BHRfS_M" | dd bs=1 count=8 of=/dev/sda seek=$((64*1024*1024+64)) # echo "_BHRfS_M" | dd bs=1 count=8 of=/dev/sda seek=$((256*1024*1024*1024+64)) ------ > > BR > G.Baroncelli -- gpg @keyserver.linux.it: Goffredo Baroncelli (kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5