From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsUBxtVjTyz7cPOsjVGBc3v1qJmtAe0mXzOscK9UU5CjCuHdjilBgdDhEt9Bnhir63ivnBk ARC-Seal: i=1; a=rsa-sha256; t=1521206667; cv=none; d=google.com; s=arc-20160816; b=H1F7tNUErT2fiVmh+AqlY3ip2goY8bdzKPTJN/WZ+QiynaH3BVbe/butQoiw/41cEm xoiaTnsQ4v7dNSbVVtWDJHsH4TbuKt+dSBZr3PN2zhejkPq3IqO+1+IbCmrGGRm8EjC0 /oVZZfAkZQOrlPZrekCVxcB6ulJiz9Svu1aJg5cWDs+HciP6m4wapprSdFeh5e7axOxx qqiN4PSz+Rl8PLNUx7+ZHW7/0wKzfhLofvlI0SziA3H00QD1ul01OVRvSdIy4fPFDX0D uuY1v/FGp9PT1Lb1ByBLeC97SQfczK3C5PcEMPDod365Agk8YPQ6nPiasQyR+TSAtNK3 TEag== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :mail-followup-to:reply-to:message-id:subject:cc:to:from:date :arc-authentication-results; bh=mAIlOlfRKInv63fTmT6G9/y4B7bsKlpBUVwqbSqOo0U=; b=HTkdZKLufoXFrUjmv0m8IqyQa2t8ONgyr7inhhlF09hAU+zlpATqgEBzT2LTlB7DwQ a6ABvRNL3jt9ExJOY4mMEjnUQ90Som49qpNQdPkbBB1XeaqJsz4Oys16nwjLmTxSXWS8 Tx3jKerSyQJSG1KPxZ6OYB4hoFIaT1Zm3FwxNpU4pMFT2MqrkdWakENl5bT9g6lwD1uA OztXyabZOlhlCDsHxLgNxpHrB/SDrs+MQM0Az+nVcaFTznuRnUPjSg4urGYZx46OYrDr puZFJFZZIUALahF8X7DWMvKMTgvLA9DDbt/8BhdZyoiYtNIMccCe+sJ+GluWgHtyUhJ2 i19Q== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dsterba@suse.cz designates 195.135.220.15 as permitted sender) smtp.mailfrom=dsterba@suse.cz Authentication-Results: mx.google.com; spf=pass (google.com: domain of dsterba@suse.cz designates 195.135.220.15 as permitted sender) smtp.mailfrom=dsterba@suse.cz Date: Fri, 16 Mar 2018 14:22:02 +0100 From: David Sterba To: Greg Kroah-Hartman Cc: Christoph Biedl , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Anand Jain , Liu Bo , David Sterba Subject: Re: [PATCH 4.14 024/110] btrfs: use proper endianness accessors for super_copy Message-ID: <20180316132202.GB8297@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Greg Kroah-Hartman , Christoph Biedl , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Anand Jain , Liu Bo , David Sterba References: <20180307191039.748351103@linuxfoundation.org> <20180307191042.810088712@linuxfoundation.org> <1521139304@msgid.manchmal.in-ulm.de> <20180316123049.GC25079@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180316123049.GC25079@kroah.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594309090147375870?= X-GMAIL-MSGID: =?utf-8?q?1595100802777288681?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri, Mar 16, 2018 at 01:30:49PM +0100, Greg Kroah-Hartman wrote: > On Thu, Mar 15, 2018 at 07:55:42PM +0100, Christoph Biedl wrote: > > Greg Kroah-Hartman wrote... > > > > > 4.14-stable review patch. If anyone has any objections, please let me know. > > > > > commit 3c181c12c431fe33b669410d663beb9cceefcd1b upstream. > > (...) > > > > > If the filesystem is always used on a same endian host, this will not > > > be a problem. > > > > >From my observations I cannot quite subscribe to that. > > > > On big-endian systems, this change intruduces severe corruption, > > resulting in complete loss of the data on the used block device. > > > > Steps to reproduce (tested on ppc/powerpc and parisc/hppa): > > > > # mkfs.btrfs $DEV > > # mount $DEV /mnt/tmp/ > > # umount /mnt/tmp/ > > > > This simple umount corrupts the file system: > > > > # mount $DEV /mnt/tmp/ > > mount: /mnt/tmp: wrong fs type, bad option, bad superblock on $DEV, missing codepage or helper program, or other error. > > > > # dmesg: > > BTRFS critical (device ): unable to find logical 4294967296 length 4096 > > BTRFS critical (device ): unable to find logical 4294967296 length 4096 > > BTRFS critical (device ): unable to find logical 18102363734671360 length 16384 > > BTRFS error (device ): failed to read chunk root > > BTRFS error (device ): open_ctree failed > > > > Also fsck is of no help: > > > > # btrfsck $DEV > > Couldn't map the block 18102363734671360 > > No mapping for 18102363734671360-18102363734687744 > > Couldn't map the block 18102363734671360 > > bytenr mismatch, want=18102363734671360, have=0 > > ERROR: cannot read chunk root > > ERROR: cannot open file system > > > > > > Trying mount or fsck on a little-endian system does not help either. So > > I consider the data on that device lost - luckily I use btrfs only for > > files where a backup exists all the time. > > > > > > Reverting that change restored the previous error-free behaviour. I > > didn't check HEAD, i.e. v4.16-rc5, since the upstream commt was the last > > that affected these files. Still I could give this a try if anybody > > wishes so. > > That sucks. Can you test Linus's tree to verify the problem is there? > I'll gladly revert this if Linus's tree also gets the revert, I don't > want you to hit this when you upgrade to a newer kernel. I'll push a fix for the upcoming rc but I think it would be better to remove the broken patch from stable kernels ASAP, so I'd recommend to revert it now.