Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932165Ab2EYRtu (ORCPT ); Fri, 25 May 2012 13:49:50 -0400 Received: from mo-p00-ob.rzone.de ([81.169.146.160]:13918 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751434Ab2EYRts (ORCPT ); Fri, 25 May 2012 13:49:48 -0400 X-RZG-AUTH: :P24BfVKtdewSqNxKJHA7pzS3qMJDcjZcfhyLxL2IOTrSfPdWpt8NAU6Rd4owBwqu9S/CLYgB X-RZG-CLASS-ID: mo00 Message-ID: <4FBFC63B.6050403@giantdisaster.de> Date: Fri, 25 May 2012 19:49:47 +0200 From: Stefan Behrens User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Christoph Hellwig CC: linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 0/3] Btrfs: add IO error device stats References: <1337954770-10086-1-git-send-email-sbehrens@giantdisaster.de> <20120525151854.GA23362@infradead.org> In-Reply-To: <20120525151854.GA23362@infradead.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2408 Lines: 56 It would be helpful if already the generic block layer would offer device error counters. Then btrfs could read them, add own counters for its checksum detected errors, and store everything persistently in the filesystem. The goal is to replace disks that have an increased error rate with spare disks, and the goal is to repair this degenerated RAID state quickly. On 05/25/2012 17:18, Christoph Hellwig wrote: > Can you explain why the device error counters should be in a filesystem > instead of generic block layer code? > > On Fri, May 25, 2012 at 04:06:07PM +0200, Stefan Behrens wrote: [...] >> The goal is to detect when drives start to get an increased error rate, >> when drives should be replaced soon. Therefore statistic counters are >> added that count IO errors (read, write and flush). Additionally, the >> software detected errors like checksum errors and corrupted blocks are >> counted. >> >> An ioctl interface is added to get the device statistic counters. >> A second ioctl is added to atomically get and reset these counters. >> >> The device statistics are written into the device tree with each >> transaction commit. Only modified statistics are written. >> When a filesystem is mounted, the device statistics for each involved >> device are read from the device tree and used to initialize the >> counters. >> >> A patch for the btrfs-progs world will also be sent. >> >> Stefan Behrens (3): >> Btrfs: add device counters for detected IO and checksum errors >> Btrfs: add ioctl to get and reset the device stats >> Btrfs: read device stats on mount, write modified ones during commit >> >> fs/btrfs/ctree.h | 38 ++++++ >> fs/btrfs/disk-io.c | 20 +++- >> fs/btrfs/extent_io.c | 18 ++- >> fs/btrfs/ioctl.c | 26 +++++ >> fs/btrfs/ioctl.h | 33 ++++++ >> fs/btrfs/print-tree.c | 3 + >> fs/btrfs/scrub.c | 65 ++++++++--- >> fs/btrfs/transaction.c | 4 + >> fs/btrfs/volumes.c | 304 +++++++++++++++++++++++++++++++++++++++++++++++- >> fs/btrfs/volumes.h | 52 +++++++++ >> 10 files changed, 539 insertions(+), 24 deletions(-) >> >> -- >> 1.7.10.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/