From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f52.google.com ([209.85.218.52]:35975 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbcGGR5K (ORCPT ); Thu, 7 Jul 2016 13:57:10 -0400 Received: by mail-oi0-f52.google.com with SMTP id f189so33597512oig.3 for ; Thu, 07 Jul 2016 10:57:09 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <0120508a-b9e7-b9e7-4f27-79f982ee07fe@fastmail.fm> References: <0120508a-b9e7-b9e7-4f27-79f982ee07fe@fastmail.fm> From: Chris Murphy Date: Thu, 7 Jul 2016 11:57:08 -0600 Message-ID: Subject: Re: Frequent btrfs corruption on a USB flash drive To: Francesco Turco Cc: Btrfs BTRFS Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Jul 7, 2016 at 7:49 AM, Francesco Turco wrote: > $ btrfs filesystem show > /run/media/fturco/5283147c-b7b4-448f-97b0-b235344a56a3 > $ Try it with sudo. I think it's a bug that 'btrfs fi show' returns silently for non-root. It should produce an error that root privileges are needed, or it should work for unprivileged users. > Btrfs-check reports many errors. I attached the output to this e-mail > message. > > Output from dmesg: > > $ dmesg | tail > [18756.159963] BTRFS error (device dm-4): bad tree block start > 6592115285688248773 35323904 The problem happened before this, so I think we need the entire dmesg. > I checked this USB flash drive with badblocks in non-destructive > read-write mode. No errors. Use F3 to test flash: http://oss.digirati.com.br/f3/ Some distros have it in their repo, Fedora does. It's a bit unintuitive what you need to do is use the write binary to write the test files to the stick (this is destructive) and then use the read binary to read back the written files. Read more, and also includes a much faster alternative for GNOME: https://blogs.gnome.org/hughsie/2015/01/28/detecting-fake-flash/ -- Chris Murphy