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...
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)))
Thanks,
>
> Thanks,
>
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