* Re: [PATCH v2] F2FS: invalidate META_MAPPING before IPU/DIO write
2021-11-01 8:46 ` [PATCH v2] F2FS: invalidate META_MAPPING before IPU/DIO write Hyeong-Jun Kim
@ 2021-11-02 1:28 ` Chao Yu
2021-11-02 3:37 ` Chao Yu
1 sibling, 0 replies; 3+ messages in thread
From: Chao Yu @ 2021-11-02 1:28 UTC (permalink / raw)
To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel
On 2021/11/1 16:46, 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.
>
> Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")
> Signed-off-by: Hyeong-Jun Kim <hj514.kim@samsung.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Thanks,
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] F2FS: invalidate META_MAPPING before IPU/DIO write
2021-11-01 8:46 ` [PATCH v2] F2FS: invalidate META_MAPPING before IPU/DIO write Hyeong-Jun Kim
2021-11-02 1:28 ` Chao Yu
@ 2021-11-02 3:37 ` Chao Yu
1 sibling, 0 replies; 3+ messages in thread
From: Chao Yu @ 2021-11-02 3:37 UTC (permalink / raw)
To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel, guoweichao
On 2021/11/1 16:46, 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.
>
> Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")
> Signed-off-by: Hyeong-Jun Kim <hj514.kim@samsung.com>
> ---
> 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..f57c55190f9e 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(fio->sbi),
There is one more comment from Weichao:
Use sbi instead of fio->sbi?
Thanks,
> + fio->new_blkaddr, fio->new_blkaddr);
> +
> stat_inc_inplace_blocks(fio->sbi);
>
> if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 << F2FS_IPU_NOCACHE)))
>
^ permalink raw reply [flat|nested] 3+ messages in thread