[PATCH 6.12 41/42] f2fs: fix IS_CHECKPOINTED flag inconsistency issue caused by concurrent atomic commit and checkpoint writes

Greg Kroah-Hartman
2026-02-17T20:54:34Z

From: Yongpeng Yang <yangyongpeng@xiaomi.com>

[ Upstream commit 7633a7387eb4d0259d6bea945e1d3469cd135bbc ]

During SPO tests, when mounting F2FS, an -EINVAL error was returned from
f2fs_recover_inode_page. The issue occurred under the following scenario

Thread A Thread B
f2fs_ioc_commit_atomic_write
- f2fs_do_sync_file // atomic = true
- f2fs_fsync_node_pages
: last_folio = inode folio
: schedule before folio_lock(last_folio) f2fs_write_checkpoint
- block_operations// writeback last_folio
- schedule before f2fs_flush_nat_entries
: set_fsync_mark(last_folio, 1)
: set_dentry_mark(last_folio, 1)
: folio_mark_dirty(last_folio)
- __write_node_folio(last_folio)
: f2fs_down_read(&sbi->node_write)//block
- f2fs_flush_nat_entries
: {struct nat_entry}->flag |= BIT(IS_CHECKPOINTED)
- unblock_operations
: f2fs_up_write(&sbi->node_write)
f2fs_write_checkpoint//return
: f2fs_do_write_node_page()
f2fs_ioc_commit_atomic_write//return
SPO

Thread A calls f2fs_need_dentry_mark(sbi, ino), and the last_folio has
already been written once. However, the {struct nat_entry}->flag did not
have the IS_CHECKPOINTED set, causing set_dentry_mark(last_folio, 1) and
write last_folio again after Thread B finishes f2fs_write_checkpoint.

After SPO and reboot, it was detected that {struct node_info}->blk_addr
was not NULL_ADDR because Thread B successfully write the checkpoint.

This issue only occurs in atomic write scenarios. For regular file
fsync operations, the folio must be dirty. If
block_operations->f2fs_sync_node_pages successfully submit the folio
write, this path will not be executed. Otherwise, the
f2fs_write_checkpoint will need to wait for the folio write submission
to complete, as sbi->nr_pages[F2FS_DIRTY_NODES] > 0. Therefore, the
situation where f2fs_need_dentry_mark checks that the {struct
nat_entry}->flag /wo the IS_CHECKPOINTED flag, but the folio write has
already been submitted, will not occur.

Therefore, for atomic file fsync, sbi->node_write should be acquired
through __write_node_folio to ensure that the IS_CHECKPOINTED flag
correctly indicates that the checkpoint write has been completed.

Fixes: 608514deba38 ("f2fs: set fsync mark only for the last dnode")
Cc: stable@kernel.org
Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
Signed-off-by: Jinbao Liu <liujinbao1@xiaomi.com>
Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
[ folio => page ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/f2fs/node.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1713,8 +1713,13 @@ static int __write_node_page(struct page
goto redirty_out;
}

- if (atomic && !test_opt(sbi, NOBARRIER))
- fio.op_flags |= REQ_PREFLUSH | REQ_FUA;
+ if (atomic) {
+ if (!test_opt(sbi, NOBARRIER))
+ fio.op_flags |= REQ_PREFLUSH | REQ_FUA;
+ if (IS_INODE(page))
+ set_dentry_mark(page,
+ f2fs_need_dentry_mark(sbi, ino_of_node(page)));
+ }

/* should add to global list before clearing PAGECACHE status */
if (f2fs_in_warm_node_list(sbi, page)) {
@@ -1869,8 +1874,9 @@ continue_unlock:
if (is_inode_flag_set(inode,
FI_DIRTY_INODE))
f2fs_update_inode(inode, page);
- set_dentry_mark(page,
- f2fs_need_dentry_mark(sbi, ino));
+ if (!atomic)
+ set_dentry_mark(page,
+ f2fs_need_dentry_mark(sbi, ino));
}
/* may be written by other thread */
if (!PageDirty(page))