From patchwork Tue Mar 26 11:55:24 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Shilong X-Patchwork-Id: 2336121 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 18E983FC54 for ; Tue, 26 Mar 2013 11:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758176Ab3CZLzg (ORCPT ); Tue, 26 Mar 2013 07:55:36 -0400 Received: from mail-pa0-f47.google.com ([209.85.220.47]:49755 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757614Ab3CZLzf (ORCPT ); Tue, 26 Mar 2013 07:55:35 -0400 Received: by mail-pa0-f47.google.com with SMTP id bj3so1108588pad.6 for ; Tue, 26 Mar 2013 04:55:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:from:to:cc:subject:date:message-id:x-mailer; bh=PO1JMMvAPJ3gfOrUnAY/MLLA5tO1pT9dd2z7FMTWoVU=; b=jAk9uj9ArAPxPETMQniu75wP+lzbTO9KQqlxxBIt2c9v/5ACButLGbUO66Uj9RcCjS t/ujEApHzN7E5+oQq7PecluhcAZ1kO9dBw2w2wkciTnbFIZGTrrkDBcOCmy6t48D8FgN THOPHJzngAZSeHppBLnok0pBhRacAejCVkLFOd91J25Pq+iId6k2H2zCX0Vz9vYOV/5E wOBv4IP4Fof7uuevJ8bB1NLyFO9ljJE7wVqg2qR6vs/3olIaLNYnTObnxP5g4cLqJ7dx pz/0qlTOAW6r021Y81vrHBMudvcjnCclEf6HG3dyvdBHH9e4FpXcFhYdbVudVvyfQGi0 NV+A== X-Received: by 10.68.135.168 with SMTP id pt8mr22785231pbb.10.1364298935034; Tue, 26 Mar 2013 04:55:35 -0700 (PDT) Received: from localhost.localdomain.localdomain ([223.65.184.172]) by mx.google.com with ESMTPS id fh1sm18974580pac.1.2013.03.26.04.55.32 (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 26 Mar 2013 04:55:34 -0700 (PDT) From: Wang Shilong To: linux-btrfs@vger.kernel.org Cc: sensille@gmx.net, miaox@cn.fujitsu.com, wangshilong1991@gmail.com Subject: [PATCH 1/7] Btrfs: introduce a mutex lock for btrfs quota operations Date: Tue, 26 Mar 2013 19:55:24 +0800 Message-Id: <1364298930-4507-1-git-send-email-wangshilong1991@gmail.com> X-Mailer: git-send-email 1.7.11.7 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Wang Shilong The original code only has one spin_lock 'qgroup_lock' to protect quota configurations on memory, if we want to add a BTRFS_QGROUP_INFO_KEY, it will be added to Btree firstly and then update quota configuration on memory,this case works ok just because of Btrfs internal btree lock. However, if we want to add a BTRFS_QGROUP_RELATION_KEY, this will cause problems, in fact,we need to check 'src' and 'dst' before, without an extra lock, race conditions can not be avoided. Holding mutex_lock, we can have the check before operations in safety. Besides, we can remove some spin_lock usages and ease the burdern of the global spin_lock. Signed-off-by: Wang Shilong Reviewed-by: Miao Xie --- fs/btrfs/ctree.h | 1 + fs/btrfs/disk-io.c | 1 + fs/btrfs/ioctl.c | 13 ++++++++++--- 3 files changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 6e81860..a7fec8c 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1582,6 +1582,7 @@ struct btrfs_fs_info { /* holds configuration and tracking. Protected by qgroup_lock */ struct rb_root qgroup_tree; + struct mutex quota_lock; spinlock_t qgroup_lock; /* list of dirty qgroups to be written at next commit */ diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index fe82d08..4552f14 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2250,6 +2250,7 @@ int open_ctree(struct super_block *sb, mutex_init(&fs_info->dev_replace.lock); spin_lock_init(&fs_info->qgroup_lock); + mutex_init(&fs_info->quota_lock); fs_info->qgroup_tree = RB_ROOT; INIT_LIST_HEAD(&fs_info->dirty_qgroups); fs_info->qgroup_seq = 1; diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 222ce84..0b8ab81 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3693,6 +3693,7 @@ static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg) goto drop_write; } + mutex_lock(&root->fs_info->quota_lock); down_read(&root->fs_info->subvol_sem); if (sa->cmd != BTRFS_QUOTA_CTL_RESCAN) { trans = btrfs_start_transaction(root, 2); @@ -3728,6 +3729,7 @@ static long btrfs_ioctl_quota_ctl(struct file *file, void __user *arg) out: kfree(sa); up_read(&root->fs_info->subvol_sem); + mutex_unlock(&root->fs_info->quota_lock); drop_write: mnt_drop_write_file(file); return ret; @@ -3754,6 +3756,7 @@ static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg) goto drop_write; } + mutex_lock(&root->fs_info->quota_lock); trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); @@ -3775,6 +3778,7 @@ static long btrfs_ioctl_qgroup_assign(struct file *file, void __user *arg) out: kfree(sa); + mutex_unlock(&root->fs_info->quota_lock); drop_write: mnt_drop_write_file(file); return ret; @@ -3805,11 +3809,11 @@ static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg) ret = -EINVAL; goto out; } - + mutex_lock(&root->fs_info->quota_lock); trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); - goto out; + goto out_unlock; } /* FIXME: check if the IDs really exist */ @@ -3824,6 +3828,8 @@ static long btrfs_ioctl_qgroup_create(struct file *file, void __user *arg) if (err && !ret) ret = err; +out_unlock: + mutex_unlock(&root->fs_info->quota_lock); out: kfree(sa); drop_write: @@ -3852,7 +3858,7 @@ static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg) ret = PTR_ERR(sa); goto drop_write; } - + mutex_lock(&root->fs_info->quota_lock); trans = btrfs_join_transaction(root); if (IS_ERR(trans)) { ret = PTR_ERR(trans); @@ -3874,6 +3880,7 @@ static long btrfs_ioctl_qgroup_limit(struct file *file, void __user *arg) out: kfree(sa); + mutex_unlock(&root->fs_info->quota_lock); drop_write: mnt_drop_write_file(file); return ret;