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SubjectRe: [PATCH v3] F2FS: invalidate META_MAPPING before IPU/DIO write
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On 2021/11/2 14:49, Hyeong-Jun Kim wrote:
> On Tue, 2021-11-02 at 14:47 +0800, Chao Yu wrote:
>> On 2021/11/2 12:59, Hyeong-Jun Kim wrote:
>>> Encrypted pages during GC are read and cached in META_MAPPING.
>>> However, due to cached pages in META_MAPPING, there is an issue
>>> where
>>> newly written pages are lost by IPU or DIO writes.
>>>
>>> Thread A - f2fs_gc() Thread B
>>> /* phase 3 */
>>> down_write(i_gc_rwsem)
>>> ra_data_block() ---- (a)
>>> up_write(i_gc_rwsem)
>>> f2fs_direct_IO() :
>>> - down_read(i_gc_rwsem)
>>> - __blockdev_direct_io()
>>> - get_data_block_dio_write()
>>> - f2fs_dio_submit_bio() ---- (b)
>>> - up_read(i_gc_rwsem)
>>> /* phase 4 */
>>> down_write(i_gc_rwsem)
>>> move_data_block() ---- (c)
>>> up_write(i_gc_rwsem)
>>>
>>> (a) In phase 3 of f2fs_gc(), up-to-date page is read from storage
>>> and
>>> cached in META_MAPPING.
>>> (b) In thread B, writing new data by IPU or DIO write on same
>>> blkaddr as
>>> read in (a). cached page in META_MAPPING become out-dated.
>>> (c) In phase 4 of f2fs_gc(), out-dated page in META_MAPPING is
>>> copied to
>>> new blkaddr. In conclusion, the newly written data in (b) is
>>> lost.
>>>
>>> To address this issue, invalidating pages in META_MAPPING before
>>> IPU or
>>> DIO write.
>>>
>>> ---
>>> v3:
>>> - Use sbi instead of fio->sbi in f2fs_inplace_write_data()
>>> v2:
>>> - Update patch description with race condition
>>
>>
>>
>>> Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")
>>> Signed-off-by: Hyeong-Jun Kim <
>>> hj514.kim@samsung.com
>>>>
>>> ---
>>
>> Change log should be attached here, otherwise Fixes & Signed-off-by
>> tag will be lost
>> after applying this patch.
>>
>> Thanks,
>>
> Thanks for your comment.
> Should I re-send this patch?

Yes, please. :)

Thanks,

>
> Thanks,
>>> fs/f2fs/data.c | 2 ++
>>> fs/f2fs/segment.c | 3 +++
>>> 2 files changed, 5 insertions(+)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index 74e1a350c1d8..9f754aaef558 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -1708,6 +1708,8 @@ int f2fs_map_blocks(struct inode *inode,
>>> struct f2fs_map_blocks *map,
>>> */
>>> f2fs_wait_on_block_writeback_range(inode,
>>> map->m_pblk, map-
>>>> m_len);
>>> + invalidate_mapping_pages(META_MAPPING(sbi),
>>> + map->m_pblk, map-
>>>> m_pblk);
>>>
>>> if (map->m_multidev_dio) {
>>> block_t blk_addr = map->m_pblk;
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 526423fe84ce..df9ed75f0b7a 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -3652,6 +3652,9 @@ int f2fs_inplace_write_data(struct
>>> f2fs_io_info *fio)
>>> goto drop_bio;
>>> }
>>>
>>> + invalidate_mapping_pages(META_MAPPING(sbi),
>>> + fio->new_blkaddr, fio->new_blkaddr);
>>> +
>>> stat_inc_inplace_blocks(fio->sbi);
>>>
>>> if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 <<
>>> F2FS_IPU_NOCACHE)))
>>>
>>
>>
>

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