From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from len.romanrm.net ([195.154.117.182]:53134 "EHLO len.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751021AbdCQJvI (ORCPT ); Fri, 17 Mar 2017 05:51:08 -0400 Date: Fri, 17 Mar 2017 14:51:07 +0500 From: Roman Mamedov To: Lionel Bouton Cc: Hans van Kranenburg , Btrfs BTRFS Subject: Re: help : "bad tree block start" -> btrfs forced readonly Message-ID: <20170317145107.21bb9b45@natsu> In-Reply-To: <2994d13d-c65c-0794-8a83-a68ff258f109@bouton.name> References: <0ec911af-2932-72df-d9b3-bd27616e101e@bouton.name> <4866fa5d-d9bc-653a-17d8-b555fc55491e@mendix.com> <2994d13d-c65c-0794-8a83-a68ff258f109@bouton.name> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Fri, 17 Mar 2017 10:27:11 +0100 Lionel Bouton wrote: > Hi, > > Le 17/03/2017 à 09:43, Hans van Kranenburg a écrit : > > btrfs-debug-tree -b 3415463870464 > > Here is what it gives me back : > > btrfs-debug-tree -b 3415463870464 /dev/sdb > btrfs-progs v4.6.1 > checksum verify failed on 3415463870464 found A85405B7 wanted 01010101 > checksum verify failed on 3415463870464 found A85405B7 wanted 01010101 > bytenr mismatch, want=3415463870464, have=72340172838076673 > ERROR: failed to read 3415463870464 > > Is there a way to remove part of the tree and keep the rest ? It could > help minimize the time needed to restore data. If you are able to experiment with writable snapshots, you could try using "btrfs-corrupt-block" to kill the bad block, and see what btrfsck makes out of the rest. In a similar case I got little to no damage to the overall FS. http://www.spinics.net/lists/linux-btrfs/msg53061.html -- With respect, Roman