From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id nBENBLmC185821 for ; Mon, 14 Dec 2009 17:11:21 -0600 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id E0F7FF57F4 for ; Mon, 14 Dec 2009 15:11:58 -0800 (PST) Received: from mail.internode.on.net (bld-mail12.adl6.internode.on.net [150.101.137.97]) by cuda.sgi.com with ESMTP id UwVdp50D3g81xjfZ for ; Mon, 14 Dec 2009 15:11:58 -0800 (PST) Received: from discord (unverified [121.44.201.81]) by mail.internode.on.net (SurgeMail 3.8f2) with ESMTP id 10077762-1927428 for ; Tue, 15 Dec 2009 09:41:57 +1030 (CDT) Received: from disturbed ([192.168.1.9]) by discord with esmtp (Exim 4.69) (envelope-from ) id 1NKK55-0001Ig-Lj for xfs@oss.sgi.com; Tue, 15 Dec 2009 10:11:55 +1100 Received: from dave by disturbed with local (Exim 4.69) (envelope-from ) id 1NKK4b-0003sP-Co for xfs@oss.sgi.com; Tue, 15 Dec 2009 10:11:25 +1100 From: Dave Chinner Subject: [PATCH 0/6] XFS: Fix growfs deadlocks and per-AG use after free V2 Date: Tue, 15 Dec 2009 10:11:04 +1100 Message-Id: <1260832270-14762-1-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com The use of an array for the xfs_perag structures results in growfs having to realocate the array. This requires exclusion to prevent use-after-free situations. The current locking is prone to deadlocks when growing under load, and the xfssyncd currently has no protection against the array being reallocated that can lead to panics. This series abstracts the per-ag structure access and then removes the array to replace it with individual xfs_perag structures indexed by a radix tree. The only locking required is for the radix tree, hence the deadlocks go away as the tree lock is always the innermost lock. The use after frees go away as well as growfs does not need to reallocate structures fo pre-existing allocation groups - it only needs to allocate the structures for the new AGs and insert them into the tree. This series also adds reference counting to the xfs-perag structure to ensure that we balance get/put accesses to the structures and provide the infrastructure to determine if the structure is in use or not. Version 2: Fix review comments from Christoph. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs