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

From: Chao Yu
Date: Mon Mar 27 2017 - 21:17:30 EST


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@xxxxxxxxxx>
>> ---
>> 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
>
> .
>