On 2016/10/24 5:40, Jaegeuk Kim wrote:
> On Sun, Oct 23, 2016 at 08:26:15PM +0800, Chao Yu wrote:
>> On 2016/10/15 0:57, Jaegeuk Kim wrote:
>>> On Fri, Oct 14, 2016 at 09:25:59PM +0800, Chao Yu wrote:
>>>> On 2016/10/14 1:14, Jaegeuk Kim wrote:
>>>>> On Thu, Oct 13, 2016 at 06:33:19PM +0800, Chao Yu wrote:
>>>>>> Hi Jaegeuk,
>>>>>>
>>>>>> On 2016/10/13 7:23, Jaegeuk Kim wrote:
>>>>>>> This patch fixes using a wrong pointer for sum_page in f2fs_gc.
>>>>>>>
>>>>>>> Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org>
>>>>>>> ---
>>>>>>> fs/f2fs/gc.c | 10 +++++-----
>>>>>>> 1 file changed, 5 insertions(+), 5 deletions(-)
>>>>>>>
>>>>>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>>>>>>> index e48142f..9c18917 100644
>>>>>>> --- a/fs/f2fs/gc.c
>>>>>>> +++ b/fs/f2fs/gc.c
>>>>>>> @@ -854,16 +854,16 @@ static int do_garbage_collect(struct f2fs_sb_info
>>>>>>> *sbi,
>>>>>>>
>>>>>>> for (segno = start_segno; segno < end_segno; segno++) {
>>>>>>>
>>>>>>> - if (get_valid_blocks(sbi, segno, 1) == 0 ||
>>>>>>> - unlikely(f2fs_cp_error(sbi)))
>>>>>>> - goto next;
>>>>>>> -
>>>>>>> /* find segment summary of victim */
>>>>>>> sum_page = find_get_page(META_MAPPING(sbi),
>>>>>>> GET_SUM_BLOCK(sbi, segno));
>>>>>>> - f2fs_bug_on(sbi, !PageUptodate(sum_page));
>>>>>>> f2fs_put_page(sum_page, 0);
>>>>>>>
>>>>>>> + if (get_valid_blocks(sbi, segno, 1) == 0 ||
>>>>>>> + !PageUptodate(sum_page) ||
>>>>>>
>>>>>> Why uptodate flag of summary page can be cleared? someone truncates it?
>>>>>
>>>>> Well, it looks like no problem to remove this, since it will hit
>>>>> f2fs_cp_error(). I just intended to handle the above f2fs_bug_on here.
>>>>
>>>> If summary page becomes non-uptodate, it seems there is a bug in
>>>> vfs/mm/f2fs,
>>>> why not keep it there to detect bug?
>>>
>>> I found that the above get_sum_page() loop can give a page which is not
>>> uptodate
>>> caused by EIO. Then, we would get the above bug_on, if we move
>>> f2fs_cp_error()
>>> case like this patch.
>>>
>>> Thoughts?
>>
>> Seems this patch has already been merged into linus' tree...
>
> Yup.
>
>> Anyway, I can understand why you remove f2fs_bug_on & add PageUptodate here,
>> but
>> why should we repositon below check?
>>
>> if (get_valid_blocks(sbi, segno, 1) == 0 ||
>> unlikely(f2fs_cp_error(sbi)))
>
> Given description, this fixes using wrong sum_page pointer by:
>
> next:
> f2fs_put_page(sum_page, 0);
That's right, I'm missing this reference. Thanks for the explanation. :)
thanks,
>
> Thanks,
>
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