On Mon, 2021-11-01 at 14:28 +0800, Chao Yu wrote: > On 2021/11/1 13:42, 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 Thread B > > - f2fs_gc(): blk 0x10 -> 0x20 (a) > > - IPU or DIO write on blk > > 0x20 (b) > > - f2fs_gc(): blk 0x20 -> 0x30 (c) > > > > (a) page for blk 0x20 is cached in META_MAPPING and page for blk > > 0x10 > > is invalidated from META_MAPPING. > > (b) write new data to blk 0x200 using IPU or DIO, but outdated data > > still remains in META_MAPPING. > > (c) f2fs_gc() try to move blk from 0x20 to 0x30 using cached page > > in > > META_MAPPING. In conclusion, the newly written data in (b) is > > lost. > > In c), f2fs_gc() will readahead encrypted block from disk via > ra_data_block() anyway, > not matter cached encrypted page of meta inode is uptodate or not, so > it's safe, right? Right, However, if DIO write is performed between phase 3 and phase 4 of f2fs_gc(), the cached page of meta_mapping will be out-dated, though it read data from disk via ra_data_block() in phase 3.
What do you think? Thanks, > > Am I missing anything? > > Thanks, > > > To address this issue, invalidating pages in META_MAPPING before > > IPU or > > DIO write. > > > > Signed-off-by: Hyeong-Jun Kim < > > [email protected] > > > > > --- > > 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), > > + fio->new_blkaddr, fio->new_blkaddr); > > + > > stat_inc_inplace_blocks(fio->sbi); > > > > if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 << > > F2FS_IPU_NOCACHE))) > > > > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
