f2fs: fix to invalidate META_MAPPING before DIO write
authorChao Yu <chao@kernel.org>
Wed, 6 Jul 2022 06:30:15 +0000 (14:30 +0800)
committerJaegeuk Kim <jaegeuk@kernel.org>
Sun, 31 Jul 2022 03:16:20 +0000 (20:16 -0700)
commit67ca06872eb02944b4c6f92cffa9242e92c63109
tree1480df337ba642e4cffcbbcbddf3f9d429c9bae8
parent8e0f54a70e9b0c88d6375933d281d631b7248153
f2fs: fix to invalidate META_MAPPING before DIO write

Quoted from commit e3b49ea36802 ("f2fs: invalidate META_MAPPING before
IPU/DIO write")

"
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.
"

In previous commit, we missed to cover extent cache hit case, and passed
wrong value for parameter @end of invalidate_mapping_pages(), fix both
issues.

Fixes: 6aa58d8ad20a ("f2fs: readahead encrypted block during GC")
Fixes: e3b49ea36802 ("f2fs: invalidate META_MAPPING before IPU/DIO write")
Cc: Hyeong-Jun Kim <hj514.kim@samsung.com>
Signed-off-by: Chao Yu <chao.yu@oppo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
fs/f2fs/data.c