From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joseph Qi <joseph.qi@huawei.com>
Date: Wed, 29 Jul 2015 08:59:57 +0800
Subject: [Ocfs2-devel] [PATCH] ocfs2: fix shift left overflow
In-Reply-To: <20150728174011.72a7380f.akpm@linux-foundation.org>
References: <55B5A7E4.6050600@huawei.com>
	<20150728135137.707a604dfd5221c952e300e8@linux-foundation.org>
	<55B81EC3.9060603@huawei.com>
	<20150728174011.72a7380f.akpm@linux-foundation.org>
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To: ocfs2-devel@oss.oracle.com

On 2015/7/29 8:40, Andrew Morton wrote:
> On Wed, 29 Jul 2015 08:30:59 +0800 Joseph Qi <joseph.qi@huawei.com> wrote:
> 
>> On 2015/7/29 4:51, Andrew Morton wrote:
>>> On Mon, 27 Jul 2015 11:39:16 +0800 Joseph Qi <joseph.qi@huawei.com> wrote:
>>>
>>>> cluster pos is defined as u32, when calculate corresponding sector it
>>>> should be converted to u64 first, otherwise it may overflow.
>>>
>>> What are the runtime effects of this change?
>>>
>> The issue is when using large volume, for example, 9T volume with 2T already
>> used, frequently create small files with O_DIRECT and the IO is not cluster
>> aligned, it may clear sectors in the wrong place.
> 
> You mean it corrupts the filesystem?
> 
> So this wants to be merged asap and backported as far as possible?
> 
Yes, it only affects kernel 4.0+.

>