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f2fs: force out-place update for all writes on compressed file

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For compressed file, compressed write may fail and fall back to raw
write.

-Thread A                                         - Thread B
  - f2fs_write_multi_pages                          - f2fs_down_write(&sbi->cp_rwsem);
   - f2fs_write_compressed_pages                    - ...
    - f2fs_trylock_op                               - ...
     - f2fs_down_read_trylock(&sbi->cp_rwsem);      - ...
   - f2fs_write_raw_pages                           - ...

Thread B acquires the lock first, which causes Thread A to fail lock
acquisition and fall back to raw-data write.
IPU_FORCE is enabled on small-capacity storage devices (< 16GB),
so f2fs_write_raw_pages() overwrites the original compressed data
in-place.

The in-memory node has been updated with raw-data addresses, while the
node metadata stored on eMMC still remains in compressed state.
If a power-cut occurs before the node is flushed to disk, on-disk
inconsistency arises: disk data is raw, yet metadata treats it as a
compressed cluster, leading to decompression failure.

To eliminate this risk completely, force out-place update for all
write operations on compressed file.

Cc: stable@kernel.org
Fixes: 4c8ff7095b ("f2fs: support data compression")
Signed-off-by: Jiucheng Xu <jiucheng.xu@amlogic.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jiucheng Xu 2026-09-07 19:35:42 +08:00 committed by Jaegeuk Kim
parent 06768d77ed
commit a64a3fec11
1 changed files with 6 additions and 4 deletions
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10
fs/f2fs/data.c
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@ -2914,10 +2914,12 @@ bool f2fs_should_update_outplace(struct inode *inode, struct f2fs_io_info *fio)
return true;
if (f2fs_used_in_atomic_write(inode))
return true;
/* rewrite low ratio compress data w/ OPU mode to avoid fragmentation */
if (f2fs_compressed_file(inode) &&
F2FS_OPTION(sbi).compress_mode == COMPR_MODE_USER &&
is_inode_flag_set(inode, FI_ENABLE_COMPRESS))
/*
* rewrite low ratio compress data w/ OPU mode to avoid fragmentation.
* If IO comes from compressed write path and fallback to raw write,
* force out‑place to prevent metadata‑data inconsistency.
*/
if (f2fs_compressed_file(inode))
return true;
/* swap file is migrating in aligned write mode */