* [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write [not found] <CGME20211101054217epcas1p3c695f37ab925f47156bd45e3adb5ed94@epcas1p3.samsung.com> @ 2021-11-01 5:42 ` Hyeong-Jun Kim 2021-11-01 6:28 ` Chao Yu 0 siblings, 1 reply; 7+ messages in thread From: Hyeong-Jun Kim @ 2021-11-01 5:42 UTC (permalink / raw) To: Jaegeuk Kim, Chao Yu; +Cc: linux-kernel, linux-f2fs-devel 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 (b) write new data to blk 0x200 using IPU or DIO, but outdated data still remains in META_MAPPING.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. To address this issue, invalidating pages in META_MAPPING before IPU or DIO write. 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), + fio->new_blkaddr, fio->new_blkaddr); + stat_inc_inplace_blocks(fio->sbi); if (fio->bio && !(SM_I(sbi)->ipu_policy & (1 << F2FS_IPU_NOCACHE))) -- 2.25.1 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write 2021-11-01 5:42 ` [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write Hyeong-Jun Kim @ 2021-11-01 6:28 ` Chao Yu 2021-11-01 7:09 ` Hyeong-Jun Kim 0 siblings, 1 reply; 7+ messages in thread From: Chao Yu @ 2021-11-01 6:28 UTC (permalink / raw) To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel 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? 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 <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), > + 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 Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write 2021-11-01 6:28 ` Chao Yu @ 2021-11-01 7:09 ` Hyeong-Jun Kim 2021-11-01 7:12 ` Chao Yu 0 siblings, 1 reply; 7+ messages in thread From: Hyeong-Jun Kim @ 2021-11-01 7:09 UTC (permalink / raw) To: Chao Yu, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel 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 < > > 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), > > + 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 Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write 2021-11-01 7:09 ` Hyeong-Jun Kim @ 2021-11-01 7:12 ` Chao Yu 2021-11-01 7:23 ` Hyeong-Jun Kim 0 siblings, 1 reply; 7+ messages in thread From: Chao Yu @ 2021-11-01 7:12 UTC (permalink / raw) To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel On 2021/11/1 15:09, Hyeong-Jun Kim wrote: > 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? Due to i_gc_rwsem lock coverage, the race condition should not happen right now? Thanks, > > 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 < >>> 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), >>> + 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 Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write 2021-11-01 7:12 ` Chao Yu @ 2021-11-01 7:23 ` Hyeong-Jun Kim 2021-11-01 8:11 ` Chao Yu 0 siblings, 1 reply; 7+ messages in thread From: Hyeong-Jun Kim @ 2021-11-01 7:23 UTC (permalink / raw) To: Chao Yu, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote: > On 2021/11/1 15:09, Hyeong-Jun Kim wrote: > > 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? > > Due to i_gc_rwsem lock coverage, the race condition should not happen > right now? > - Thread A - Thread B /* phase 3 */ down_write(i_gc_rwsem) ra_data_block() up_write(i_gc_rwsem) f2fs_direct_IO() : down_read(i_gc_rwsem) __blockdev_direct_IO() ... get_ddata_block_dio_write() ... f2fs_dio_submit_bio() up_read(i_gc_rwsem) /* phase 4 */ down_write(i_gc_rwsem) move_data_block() up_write(i_gc_rwsem) It looks, i_gc_rwsem could not protect page update between phase 3 and 4. Am I missing anything? Thanks > Thanks, > > > 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 < > > > > 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), > > > > + 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 Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write 2021-11-01 7:23 ` Hyeong-Jun Kim @ 2021-11-01 8:11 ` Chao Yu 2021-11-01 8:38 ` Hyeong-Jun Kim 0 siblings, 1 reply; 7+ messages in thread From: Chao Yu @ 2021-11-01 8:11 UTC (permalink / raw) To: Hyeong-Jun Kim, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel On 2021/11/1 15:23, Hyeong-Jun Kim wrote: > On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote: >> On 2021/11/1 15:09, Hyeong-Jun Kim wrote: >>> 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? >> >> Due to i_gc_rwsem lock coverage, the race condition should not happen >> right now? >> > - Thread A - Thread B > /* phase 3 */ > down_write(i_gc_rwsem) > ra_data_block() > up_write(i_gc_rwsem) > > f2fs_direct_IO() : > > down_read(i_gc_rwsem) > > __blockdev_direct_IO() > ... > > get_ddata_block_dio_write() > ... > > f2fs_dio_submit_bio() > > up_read(i_gc_rwsem) > /* phase 4 */ > down_write(i_gc_rwsem) > move_data_block() > up_write(i_gc_rwsem) > > It looks, i_gc_rwsem could not protect page update between phase 3 and > 4. > > Am I missing anything? It looks you're right, there is a hole in between readahead and movepage functions... Could you please update the race condition description? and add a tag as below to fix stable kernel as well: Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC") Thanks, > > Thanks > >> Thanks, >> >>> 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 < >>>>> 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), >>>>> + 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 Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write 2021-11-01 8:11 ` Chao Yu @ 2021-11-01 8:38 ` Hyeong-Jun Kim 0 siblings, 0 replies; 7+ messages in thread From: Hyeong-Jun Kim @ 2021-11-01 8:38 UTC (permalink / raw) To: Chao Yu, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel On Mon, 2021-11-01 at 16:11 +0800, Chao Yu wrote: > On 2021/11/1 15:23, Hyeong-Jun Kim wrote: > > On Mon, 2021-11-01 at 15:12 +0800, Chao Yu wrote: > > > On 2021/11/1 15:09, Hyeong-Jun Kim wrote: > > > > 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? > > > > > > Due to i_gc_rwsem lock coverage, the race condition should not > > > happen > > > right now? > > > > > > > - Thread A - Thread B > > /* phase 3 */ > > down_write(i_gc_rwsem) > > ra_data_block() > > up_write(i_gc_rwsem) > > > > f2fs_direct_IO() : > > > > down_read(i_gc_rwsem) > > > > __blockdev_direct_IO() > > ... > > > > get_ddata_block_dio_write() > > ... > > > > f2fs_dio_submit_bio() > > > > up_read(i_gc_rwsem) > > /* phase 4 */ > > down_write(i_gc_rwsem) > > move_data_block() > > up_write(i_gc_rwsem) > > > > It looks, i_gc_rwsem could not protect page update between phase 3 > > and > > 4. > > > > Am I missing anything? > > It looks you're right, there is a hole in between readahead and > movepage functions... > > Could you please update the race condition description? and add a tag > as below to fix > stable kernel as well: > > Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC") > > Thanks, Thank for your comment. I will send Patch v2 with new description. Thanks, > > > Thanks > > > > > Thanks, > > > > > > > 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 < > > > > > > 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(inod > > > > > > e, > > > > > > 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 Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel ^ permalink raw reply [flat|nested] 7+ messages in thread
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2021-11-01 5:42 ` [f2fs-dev] [PATCH] F2FS: invalidate META_MAPPING before IPU/DIO write Hyeong-Jun Kim
2021-11-01 6:28 ` Chao Yu
2021-11-01 7:09 ` Hyeong-Jun Kim
2021-11-01 7:12 ` Chao Yu
2021-11-01 7:23 ` Hyeong-Jun Kim
2021-11-01 8:11 ` Chao Yu
2021-11-01 8:38 ` Hyeong-Jun Kim
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