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SubjectRe: 答复: [PATCH] fs-writeback: writebac k sb inodes: Do not increase 'total wrote' when nothi ng is written
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在 2023/9/14 14:58, Jan Kara 写道:
> On Thu 14-09-23 04:12:31, 郭纯海 wrote:
>>> On Wed 13-09-23 07:15:01, Chunhai Guo wrote:
>>>> From the dump info, there are only two pages as shown below. One is
>>>> updated and another is under writeback. Maybe f2fs counts the
>>>> writeback page as a dirty one, so get_dirty_pages() got one. As you
>>>> said, maybe this is unreasonable.
>>>>
>>>> Jaegeuk & Chao, what do you think of this?
>>>>
>>>>
>>>> crash_32> files -p 0xE5A44678
>>>> INODE NRPAGES
>>>> e5a44678 2
>>>>
>>>> PAGE PHYSICAL MAPPING INDEX CNT FLAGS
>>>> e8d0e338 641de000 e5a44810 0 5 a095
>>> locked,waiters,uptodate,lru,private,writeback
>>>> e8ad59a0 54528000 e5a44810 1 2 2036
>>> referenced,uptodate,lru,active,private
>>>
>>> Indeed, incrementing pages_skipped when there's no dirty page is a bit odd.
>>> That being said we could also harden requeue_inode() - in particular we could do
>>> there:
>>>
>>> if (wbc->pages_skipped) {
>>> /*
>>> * Writeback is not making progress due to locked buffers.
>>> * Skip this inode for now. Although having skipped pages
>>> * is odd for clean inodes, it can happen for some
>>> * filesystems so handle that gracefully.
>>> */
>>> if (inode->i_state & I_DIRTY_ALL)
>>> redirty_tail_locked(inode, wb);
>>> else
>>> inode_cgwb_move_to_attached(inode, wb);
>>> }
>>>
>>> Does this fix your problem as well?
>>>
>>> Honza
>>
>> Thank you for your reply. Did you forget the 'return' statement? Since I encountered this issue on the 4.19 kernel and there is not inode_cgwb_move_to_attached() yet, I replaced it with inode_io_list_del_locked(). So, below is the test patch I am applying. Please have a check. By the way, the test will take some time. I will provide feedback when it is finished. Thanks.
>
> Yeah, I forgot about the return.

Hi Jan,
The test is finished and this patch can fix this issue, too.
Thanks,
>
>> if (wbc->pages_skipped) {
>> /*
>> * writeback is not making progress due to locked
>> * buffers. Skip this inode for now.
>> */
>> - redirty_tail_locked(inode, wb);
>> + if (inode->i_state & I_DIRTY_ALL)
>> + redirty_tail_locked(inode, wb);
>> + else
>> + inode_io_list_del_locked(inode, wb);
>> return;
>> }
>
> Looks good. Thanks for testing!
>
> Honza

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