From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFF43FC6197 for ; Fri, 8 Nov 2019 22:22:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A67AF21848 for ; Fri, 8 Nov 2019 22:22:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728124AbfKHWV7 convert rfc822-to-8bit (ORCPT ); Fri, 8 Nov 2019 17:21:59 -0500 Received: from lithops.sigma-star.at ([195.201.40.130]:49202 "EHLO lithops.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726095AbfKHWV7 (ORCPT ); Fri, 8 Nov 2019 17:21:59 -0500 Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id F1EC1608325B; Fri, 8 Nov 2019 23:21:56 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id zWhUttuOm15m; Fri, 8 Nov 2019 23:21:56 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 98A0C6083279; Fri, 8 Nov 2019 23:21:56 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id gfl3dpalRVCY; Fri, 8 Nov 2019 23:21:56 +0100 (CET) Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by lithops.sigma-star.at (Postfix) with ESMTP id 7ABC8608325B; Fri, 8 Nov 2019 23:21:56 +0100 (CET) Date: Fri, 8 Nov 2019 23:21:56 +0100 (CET) From: Richard Weinberger To: Zygo Blaxell Cc: linux-btrfs@vger.kernel.org Message-ID: <1374130535.78772.1573251716407.JavaMail.zimbra@nod.at> In-Reply-To: <20191108220927.GR22121@hungrycats.org> References: <1591390.YpsIS3gr9g@blindfold> <20191108220927.GR22121@hungrycats.org> Subject: Re: Decoding "unable to fixup (regular)" errors MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [195.201.40.130] X-Mailer: Zimbra 8.8.12_GA_3807 (ZimbraWebClient - FF68 (Linux)/8.8.12_GA_3809) Thread-Topic: Decoding "unable to fixup (regular)" errors Thread-Index: q0XT3yBeEKha7ZKsoWEzCEo8WnuheQ== Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org ----- Ursprüngliche Mail ----- > btrfs found corrupted data on md1. You appear to be using btrfs > -dsingle on a single mdadm raid1 device, so no recovery is possible > ("unable to fixup"). > >> The system has ECC memory with md1 being a RAID1 which passes all health checks. > > mdadm doesn't have any way to repair data corruption--it can find > differences, but it cannot identify which version of the data is correct. > If one of your drives is corrupting data without reporting IO errors, > mdadm will simply copy the corruption to the other drive. If one > drive is failing by intermittently injecting corrupted bits into reads > (e.g. because of a failure in the RAM on the drive control board), > this behavior may not show up in mdadm health checks. Well, this is not cheap hardware... Possible, but not very likely IMHO >> I tried to find the inodes behind the erroneous addresses without success. >> e.g. >> $ btrfs inspect-internal logical-resolve -v -P 593483341824 / >> ioctl ret=0, total_size=4096, bytes_left=4080, bytes_missing=0, cnt=0, missed=0 >> $ echo $? >> 1 > > That usually means the file is deleted, or the specific blocks referenced > have been overwritten (i.e. there are no references to the given block in > any existing file, but a reference to the extent containing the block > still exists). Although it's not possible to reach those blocks by > reading a file, a scrub or balance will still hit the corrupted blocks. > > You can try adding or subtracting multiples of 4096 to the block number > to see if you get a hint about which inodes reference this extent. > The first block found in either direction should be a reference to the > same extent, though there's no easy way (other than dumping the extent > tree with 'btrfs ins dump-tree -t 2' and searching for the extent record > containing the block number) to figure out which. Extents can be up to > 128MB long, i.e. 32768 blocks. Thanks for the hint! > Or modify 'btrfs ins log' to use LOGICAL_INO_V2 and the IGNORE_OFFSETS > flag. > >> My kernel is 4.12.14-lp150.12.64-default (OpenSUSE 15.0), so not super recent >> but AFAICT btrfs should be sane >> there. :-) > > I don't know of specific problems with csums in 4.12, but I'd upgrade that > for a dozen other reasons anyway. One of those is that LOGICAL_INO_V2 > was merged in 4.15. > >> What could cause the errors and how to dig further? > > Probably a silent data corruption on one of the underlying disks. > If you convert this mdadm raid1 to btrfs raid1, btrfs will tell you > which disk the errors are coming from while also correcting them. Hmm, I don't really buy this reasoning. Like I said, this is not cheap/consumer hardware. Thanks, //richard