From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from postfix.iai.uni-bonn.de ([131.220.8.4]:58054 "EHLO postfix.iai.uni-bonn.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751177Ab3K3Lh3 (ORCPT ); Sat, 30 Nov 2013 06:37:29 -0500 Message-ID: <5299CC95.6010704@informatik.uni-bonn.de> Date: Sat, 30 Nov 2013 12:31:33 +0100 From: Sebastian Ochmann MIME-Version: 1.0 To: 1i5t5.duncan@cox.net Cc: linux-btrfs@vger.kernel.org Subject: Re: 2 errors when scrubbing - but I don't know what they mean References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Hello, thank you for your input. I didn't know that btrfs keeps the error counters over mounts/reboots, but that's nice. I'm still trying to figure out how such a generation error may occur in the first place. One thing I noticed looking at the btrfs code is that the generation error counter will only get incremented in the actual scrubbing code (either in "scrub_checksum_super" or in "scrub_handle_errored_block", both in scrub.c - please correct me if I'm wrong, I'm not a btrfs dev). Also, the dmesg errors I saw were not there at boot time, but about 10 minutes after boot which was about the time when I started the scrub so I'm pretty sure that it was the scrub that detected the errors. The question remains what can cause superblock/gen errors. Sure it could be "some" read error, but I'd really like to make sure that it's not a systematic error. I wasn't able to reproduce it yet though. Best Sebastian