From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out3-smtp.messagingengine.com ([66.111.4.27]:55485 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752214AbcGGOzU (ORCPT ); Thu, 7 Jul 2016 10:55:20 -0400 Subject: Re: Frequent btrfs corruption on a USB flash drive To: "Austin S. Hemmelgarn" , linux-btrfs@vger.kernel.org References: <0120508a-b9e7-b9e7-4f27-79f982ee07fe@fastmail.fm> <87efcca5-6871-2dde-e2df-40602f1a24c2@gmail.com> From: Francesco Turco Message-ID: Date: Thu, 7 Jul 2016 16:55:18 +0200 MIME-Version: 1.0 In-Reply-To: <87efcca5-6871-2dde-e2df-40602f1a24c2@gmail.com> Content-Type: text/plain; charset=utf-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2016-07-07 16:27, Austin S. Hemmelgarn wrote: > This seems odd, are you trying to access anything over NFS or some other > network filesystem protocol here? If not, then I believe you've found a > bug, because I'm pretty certain we shouldn't be returning -ESTALE for > anything. No, I don't use NFS or any other network filesystem. > The question here is: Do you get any data corruption when using ext4? > Quite often when there's a hardware issue, you won't see _any_ > indication of it other than corrupted files when using something like > ext4 or XFS, but it will show up almost immediately with BTRFS because > we validate checksums on almost everything. There have been at least a > couple of times I've found disk issues while converting from ext4 to > BTRFS that I didn't know existed before, and then going back was able to > reliable reproduce using other tools. > > Also, FWIW, badblocks is not necessarily a reliable test method for > flash drives, they often handle serialized reads like badblocks does > very well even when failing. I'm not sure. Commands don't fail explicitely when I use ext4, but I agree with you that I may get corruption silently nonetheless. Perhaps I should try to rule out an hardware problem by filling my USB flash drive with a large random file and then checking if its SHA-1 checksum corresponds to the original copy on the hard disk. But first I probably should backup the current Btrfs filesystem with the dd command. Can I proceed? > Just to clarify, you're using BTRFS on top of disk encryption (LUKS? Or > is it just raw encryption, or even something completely different?), on > a USB flash drive (not a USB to SATA adapter with an SSD or HDD in it), > correct? I'm using a btrfs filesystem on a GUID partition encrypted with LUKS. It's a Kingston USB flash drive connected directly to my desktop machine via USB. It's definitively not a SSD or a HDD, and I'm not using any adapter. -- Website: http://www.fturco.net/ GPG key: 6712 2364 B2FE 30E1 4791 EB82 7BB1 1F53 29DE CD34