linux-kernel - Re: [PATCH 3/3] f2fs: prevent waiter encountering incorrect discard states

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Message-ID: <b435e31f-5413-b392-4fc7-d0bcb1ef2600@huawei.com>
Date:   Sat, 1 Apr 2017 14:54:08 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
CC:     <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>, <chao@...nel.org>
Subject: Re: [PATCH 3/3] f2fs: prevent waiter encountering incorrect discard
 states

Ping,

Any problem here?

Thanks,

On 2017/3/28 9:17, Chao Yu wrote:
> On 2017/3/28 7:56, Jaegeuk Kim wrote:
>> On 03/27, Chao Yu wrote:
>>> In f2fs_submit_discard_endio, we will wake up waiter before setting
>>> discard command states, so waiter may use incorrect states. Change
>>> the order between complete() and states setting to fix this issue.
>>>
>>> Signed-off-by: Chao Yu <yuchao0@...wei.com>
>>> ---
>>>  fs/f2fs/segment.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 57a81f9c8c14..9f9542c9fe47 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -717,9 +717,9 @@ static void f2fs_submit_discard_endio(struct bio *bio)
>>>  {
>>>  	struct discard_cmd *dc = (struct discard_cmd *)bio->bi_private;
>>>  
>>> -	complete(&dc->wait);
>>>  	dc->error = bio->bi_error;
>>>  	dc->state = D_DONE;
>>> +	complete(&dc->wait);
>>
>> If we set D_DONE first, the object can be released by __remove_discard_cmd()?
> 
> Yes, I think so.
> 
> Thanks,
> 
>>
>> Thanks,
>>
>>>  	bio_put(bio);
>>>  }
>>>  
>>> -- 
>>> 2.8.2.295.g3f1c1d0
>>
>> .
>>