From: Niu Yawei Subject: [PATCH 1/3 v2] quota: protect Q_GETFMT by dqonoff_mutex Date: Wed, 28 May 2014 09:52:19 +0800 Message-ID: <53854153.40601@gmail.com> References: <537DD5BA.1050105@gmail.com> <538464AD.6050407@gmail.com> <20140527101219.GA28035@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, yawei.niu@intel.com, andreas.dilger@intel.com, lai.siyao@intel.com To: Christoph Hellwig , jack@suse.cz Return-path: Received: from mail-pa0-f49.google.com ([209.85.220.49]:33426 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751413AbaE1BwM (ORCPT ); Tue, 27 May 2014 21:52:12 -0400 In-Reply-To: <20140527101219.GA28035@infradead.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: Remove dqptr_sem to make quota code scalable: Protect the Q_GETFMT by dqonoff_mutex instead of dqptr_sem. Signed-off-by: Lai Siyao Signed-off-by: Niu Yawei --- fs/quota/quota.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/quota/quota.c b/fs/quota/quota.c index 2b363e2..e4851cb 100644 --- a/fs/quota/quota.c +++ b/fs/quota/quota.c @@ -79,13 +79,13 @@ static int quota_getfmt(struct super_block *sb, int type, void __user *addr) { __u32 fmt; - down_read(&sb_dqopt(sb)->dqptr_sem); + mutex_lock(&sb_dqopt(sb)->dqonoff_mutex); if (!sb_has_quota_active(sb, type)) { - up_read(&sb_dqopt(sb)->dqptr_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); return -ESRCH; } fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id; - up_read(&sb_dqopt(sb)->dqptr_sem); + mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex); if (copy_to_user(addr, &fmt, sizeof(fmt))) return -EFAULT; return 0; -- 1.7.1