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f2fs: fix to invalidate META_MAPPING before DIO write
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Quoted from commit e3b49ea ("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: 6aa58d8 ("f2fs: readahead encrypted block during GC")
Fixes: e3b49ea ("f2fs: invalidate META_MAPPING before IPU/DIO write")
Cc: Hyeong-Jun Kim <[email protected]>
Signed-off-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
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chaseyu authored and Jaegeuk Kim committed Jul 31, 2022
1 parent 8e0f54a commit 67ca068
Showing 1 changed file with 5 additions and 2 deletions.
7 changes: 5 additions & 2 deletions fs/f2fs/data.c
Original file line number Diff line number Diff line change
Expand Up @@ -1463,9 +1463,12 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
*map->m_next_extent = pgofs + map->m_len;

/* for hardware encryption, but to avoid potential issue in future */
if (flag == F2FS_GET_BLOCK_DIO)
if (flag == F2FS_GET_BLOCK_DIO) {
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 + map->m_len - 1);
}

if (map->m_multidev_dio) {
block_t blk_addr = map->m_pblk;
Expand Down Expand Up @@ -1682,7 +1685,7 @@ 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);
map->m_pblk, map->m_pblk + map->m_len - 1);

if (map->m_multidev_dio) {
block_t blk_addr = map->m_pblk;
Expand Down

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