From patchwork Tue Sep 13 09:03:05 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Carlos Maiolino X-Patchwork-Id: 9328575 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8F0EA60231 for ; Tue, 13 Sep 2016 09:03:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7CB04291FF for ; Tue, 13 Sep 2016 09:03:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6F36B29210; Tue, 13 Sep 2016 09:03:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from oss.sgi.com (oss.sgi.com [192.48.182.195]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 72E19291FF for ; Tue, 13 Sep 2016 09:03:17 +0000 (UTC) Received: from oss.sgi.com (localhost [IPv6:::1]) by oss.sgi.com (Postfix) with ESMTP id 49F5D7CA3; Tue, 13 Sep 2016 04:03:16 -0500 (CDT) X-Original-To: xfs@oss.sgi.com Delivered-To: xfs@oss.sgi.com Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 3633A7CA2 for ; Tue, 13 Sep 2016 04:03:14 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay2.corp.sgi.com (Postfix) with ESMTP id EB584304062 for ; Tue, 13 Sep 2016 02:03:10 -0700 (PDT) X-ASG-Debug-ID: 1473757389-0bf57c1b086dd2d0001-NocioJ Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id LjTw8VfYOeZKCiyq (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Tue, 13 Sep 2016 02:03:09 -0700 (PDT) X-Barracuda-Envelope-From: cmaiolino@redhat.com X-Barracuda-Effective-Source-IP: mx1.redhat.com[209.132.183.28] X-Barracuda-Apparent-Source-IP: 209.132.183.28 X-ASG-Whitelist: Client Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D37D2C04B317; Tue, 13 Sep 2016 09:03:08 +0000 (UTC) Received: from gfs-i24c-02.mpc.lab.eng.bos.redhat.com (gfs-i24c-02.mpc.lab.eng.bos.redhat.com [10.16.144.214]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8D937Jv011156; Tue, 13 Sep 2016 05:03:08 -0400 From: Carlos Maiolino To: linux-xfs@vger.kernel.org, xfs@oss.sgi.com Subject: [PATCH V4] xfs: Document error handlers behavior Date: Tue, 13 Sep 2016 05:03:05 -0400 X-ASG-Orig-Subj: [PATCH V4] xfs: Document error handlers behavior Message-Id: <1473757385-81633-1-git-send-email-cmaiolino@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 13 Sep 2016 09:03:08 +0000 (UTC) X-Barracuda-Connect: mx1.redhat.com[209.132.183.28] X-Barracuda-Start-Time: 1473757389 X-Barracuda-Encrypted: ECDHE-RSA-AES256-GCM-SHA384 X-Barracuda-URL: https://192.48.176.15:443/cgi-mod/mark.cgi X-Barracuda-Scan-Msg-Size: 4005 X-Virus-Scanned: by bsmtpd at sgi.com X-Barracuda-BRTS-Status: 1 X-BeenThere: xfs@oss.sgi.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com X-Virus-Scanned: ClamAV using ClamSMTP Document the implementation of error handlers into sysfs. Signed-off-by: Carlos Maiolino --- Changelog: V2: - Add a description of the precedence order of each option, focusing on the behavior of "fail_at_unmount" which was not well explained in V1 V3: - Fix English spelling mistakes suggested by Eric V4: - Typo mistakes, document ENODEV default value for max_retries, fix directories's hierarchy description Documentation/filesystems/xfs.txt | 75 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt index 8146e9f..374af3b 100644 --- a/Documentation/filesystems/xfs.txt +++ b/Documentation/filesystems/xfs.txt @@ -348,3 +348,78 @@ Removed Sysctls ---- ------- fs.xfs.xfsbufd_centisec v4.0 fs.xfs.age_buffer_centisecs v4.0 + +Error handling +============== + +XFS can act differently according to the type of error found +during its operation. The implementation introduces the following +concepts to the error handler: + + -failure speed: + Defines how fast XFS should shut down when a specific error is found + during the filesystem operation. It can shut down immediately, after a + defined number of retries, after a set time period, or simply retry + forever. The old "retry forever" behavior is still the default, except + during unmount, where any IOs retrying due to errors will be cancelled + and unmount will be allowed to proceed. + + -error classes: + Specifies the subsystem/location of the error handlers, such as + metadata or memory allocation. Only metadata IO errors are handled + at this time. + + -error handlers: + Defines the behavior for a specific error. + +The filesystem behavior during an error can be set via sysfs files, Each +configuration option works independently, the first condition met for a +specific configuration will cause the filesystem to shut down. + +The configuration files are organized into the following hierarchy: + + /sys/fs/xfs//error/// + +Each directory contains: + + /sys/fs/xfs//error/ + + fail_at_unmount (Min: 0 Default: 1 Max: 1) + Defines the global error behavior at unmount time. If set to the + default value of 1, XFS will cancel any pending IO retries, shut + down, and unmount. If set to 0, pending IO retries may prevent + the filesystem from unmounting. + + subdirectories + Contains specific error handlers configuration + (Ex: /sys/fs/xfs//error/metadata, see below). + + /sys/fs/xfs//error// + + Directory containing configuration for a specific error ; + currently only the "metadata" is implemented. + The contents of this directory are specific, since each + might need to handle different types of errors. + + /sys/fs/xfs//error/// + + Contains the failure speed configuration files for specific errors in + this , as well as a "default" behavior. Each directory + contains the following configuration files: + + max_retries (Min: -1 Default: -1 Max: INTMAX) + Defines the allowed number of retries of a specific error before + the filesystem will shut down. The default value of "-1" will + cause XFS to retry forever for this specific error. Setting it + to "0" will cause XFS to fail immediately when the specific + error is found, and setting it to "N," where N is greater than 0, + will make XFS retry "N" times before shutting down. + Default value for ENODEV error is set to '0', once there is no + reason to keep retrying if the device is gone. + + retry_timeout_seconds (Min: 0 Default: 0 Max: 1 day) + Define the amount of time (in seconds) that the filesystem is + allowed to retry its operations when the specific error is + found. The default value of "0" will cause XFS to retry forever. + +