From patchwork Mon Nov 19 09:20:06 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miao Xie X-Patchwork-Id: 1763581 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id A30E63FCA5 for ; Mon, 19 Nov 2012 09:19:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753112Ab2KSJTt (ORCPT ); Mon, 19 Nov 2012 04:19:49 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:20474 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753004Ab2KSJTt (ORCPT ); Mon, 19 Nov 2012 04:19:49 -0500 X-IronPort-AV: E=Sophos;i="4.83,278,1352044800"; d="scan'208";a="6230190" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 19 Nov 2012 17:18:06 +0800 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id qAJ9Jljl007856; Mon, 19 Nov 2012 17:19:47 +0800 Received: from [10.167.225.199] ([10.167.225.199]) by fnstmail02.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.3) with ESMTP id 2012111917193171-1233312 ; Mon, 19 Nov 2012 17:19:31 +0800 Message-ID: <50A9F9C6.6090901@cn.fujitsu.com> Date: Mon, 19 Nov 2012 17:20:06 +0800 From: Miao Xie Reply-To: miaox@cn.fujitsu.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121029 Thunderbird/16.0.2 MIME-Version: 1.0 To: Linux Btrfs CC: Daniel J Blueman , Liu Bo , David Sterba Subject: [PATCH RESEND] Btrfs: fix deadlock when the process of delayed refs fails X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/19 17:19:31, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/19 17:19:35, Serialize complete at 2012/11/19 17:19:35 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Delayed ref mutexes are taken inside btrfs_commit_transaction. A later call fails and jumps to the cleanup_transaction label with these mutexes still held causing deadlock when they are reacquired. Fix this problem by unlocking those mutexes at the suitable place. Reported-by: Daniel J Blueman Signed-off-by: Miao Xie --- fs/btrfs/delayed-ref.c | 8 ++++++++ fs/btrfs/delayed-ref.h | 6 ++++++ fs/btrfs/extent-tree.c | 25 ++++++++++++++++++------- 3 files changed, 32 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c index ae94117..364cb90 100644 --- a/fs/btrfs/delayed-ref.c +++ b/fs/btrfs/delayed-ref.c @@ -422,6 +422,14 @@ again: return 1; } +void btrfs_release_ref_cluster(struct list_head *cluster) +{ + struct list_head *pos, *q; + + list_for_each_safe(pos, q, cluster) + list_del_init(pos); +} + /* * helper function to update an extent delayed ref in the * rbtree. existing and update must both have the same diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h index ab53005..fcc5a29 100644 --- a/fs/btrfs/delayed-ref.h +++ b/fs/btrfs/delayed-ref.h @@ -176,8 +176,14 @@ struct btrfs_delayed_ref_head * btrfs_find_delayed_ref_head(struct btrfs_trans_handle *trans, u64 bytenr); int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans, struct btrfs_delayed_ref_head *head); +static inline void btrfs_delayed_ref_unlock(struct btrfs_delayed_ref_head *head) +{ + mutex_unlock(&head->mutex); +} + int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans, struct list_head *cluster, u64 search_start); +void btrfs_release_ref_cluster(struct list_head *cluster); int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, struct btrfs_delayed_ref_root *delayed_refs, diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 3d3e2c1..43a58cb 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2160,7 +2160,6 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans, node->num_bytes); } } - mutex_unlock(&head->mutex); return ret; } @@ -2275,7 +2274,7 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans, * process of being added. Don't run this ref yet. */ list_del_init(&locked_ref->cluster); - mutex_unlock(&locked_ref->mutex); + btrfs_delayed_ref_unlock(locked_ref); locked_ref = NULL; delayed_refs->num_heads_ready++; spin_unlock(&delayed_refs->lock); @@ -2316,14 +2315,12 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans, if (ret) { printk(KERN_DEBUG "btrfs: run_delayed_extent_op returned %d\n", ret); spin_lock(&delayed_refs->lock); + btrfs_delayed_ref_unlock(locked_ref); return ret; } goto next; } - - list_del_init(&locked_ref->cluster); - locked_ref = NULL; } ref->in_tree = 0; @@ -2350,11 +2347,24 @@ static noinline int run_clustered_refs(struct btrfs_trans_handle *trans, ret = run_one_delayed_ref(trans, root, ref, extent_op, must_insert_reserved); - - btrfs_put_delayed_ref(ref); kfree(extent_op); count++; + /* + * If this node is a head, we will pick the next head to deal + * with. If there is something wrong when we process the + * delayed ref, we will end our operation. So in these two + * cases, we have to unlock the head and drop it from the + * cluster list before we release it though the code is ugly. + */ + if (btrfs_delayed_ref_is_head(ref) || ret) { + list_del_init(&locked_ref->cluster); + btrfs_delayed_ref_unlock(locked_ref); + locked_ref = NULL; + } + + btrfs_put_delayed_ref(ref); + if (ret) { printk(KERN_DEBUG "btrfs: run_one_delayed_ref returned %d\n", ret); spin_lock(&delayed_refs->lock); @@ -2510,6 +2520,7 @@ again: ret = run_clustered_refs(trans, root, &cluster); if (ret < 0) { + btrfs_release_ref_cluster(&cluster); spin_unlock(&delayed_refs->lock); btrfs_abort_transaction(trans, root, ret); return ret;