From a64a3fec11e77a3a0dc0009bdc58b925e45a1bb4 Mon Sep 17 00:00:00 2001 From: Jiucheng Xu Date: Mon, 7 Sep 2026 19:35:42 +0800 Subject: [PATCH] f2fs: force out-place update for all writes on compressed file 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: 4c8ff7095bef ("f2fs: support data compression") Signed-off-by: Jiucheng Xu Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index bc53ac21efee..22de00754678 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -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 */