Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH] ocfs2: fix the oops problem when write cloned file
To:     Gang He <GHe@suse.com>, "mark@fasheh.com" <mark@fasheh.com>,
        "jlbec@evilplan.org" <jlbec@evilplan.org>,
        "gechangwei@live.cn" <gechangwei@live.cn>,
        Shuning Zhang <sunny.s.zhang@oracle.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "ocfs2-devel@oss.oracle.com" <ocfs2-devel@oss.oracle.com>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>
References: <20200121050153.13290-1-ghe@suse.com>
 <CH2PR18MB3206F418382332EB25130477CF000@CH2PR18MB3206.namprd18.prod.outlook.com>
From:   Joseph Qi <joseph.qi@linux.alibaba.com>
Message-ID: <de23176f-5b84-a785-80a2-0bdc8e3a0fab@linux.alibaba.com>
Date:   Mon, 3 Feb 2020 13:15:30 +0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:60.0)
 Gecko/20100101 Thunderbird/60.9.1
MIME-Version: 1.0
In-Reply-To: <CH2PR18MB3206F418382332EB25130477CF000@CH2PR18MB3206.namprd18.prod.outlook.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 20/2/3 10:17, Gang He wrote:
> Hello Joseph, Changwei, Sunny and all,
> 
> Could you help to review this patch? 
> This patch will fix the oops problem caused by write ocfs2 clone files.
> The root cause is inode buffer head is NULL when calling ocfs2_refcount_cow.
> Secondly, we should use EX meta lock when calling ocfs2_refcount_cow.
> 
Before commit e74540b28556, we may also use NULL buffer head in case of
overwrite, so why there is no such issue before?

Thanks,
Joseph