• Chao Yu's avatar
    f2fs: fix to invalidate META_MAPPING before DIO write · 67ca0687
    Chao Yu authored
    Quoted from commit e3b49ea3 ("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: 6aa58d8a ("f2fs: readahead encrypted block during GC")
    Fixes: e3b49ea3 ("f2fs: invalidate META_MAPPING before IPU/DIO write")
    Cc: Hyeong-Jun Kim <hj514.kim@samsung.com>
    Signed-off-by: default avatarChao Yu <chao.yu@oppo.com>
    Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
    67ca0687
data.c 100 KB