Messages in this thread | | | Date | Tue, 2 Nov 2021 14:47:30 +0800 | Subject | Re: [PATCH v3] F2FS: invalidate META_MAPPING before IPU/DIO write | From | Chao Yu <> |
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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,
> 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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