[PATCH] f2fs: fix to let checkpoint guarantee atomic page persistence

[Chao Yu]

1. thread A: commit_inmem_pages submit data into block layer, but
haven't waited it writeback.
2. thread A: commit_inmem_pages update related node.
3. thread B: do checkpoint, flush all nodes to disk.
4. SPOR

Then, atomic file becomes corrupted since nodes is flushed before data.

This patch fixes to treat atomic page as checkpoint guaranteed one,
then in checkpoint, we can make sure all atomic page can be writebacked
with metadata of atomic file.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
 fs/f2fs/data.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 778b23fce4fa..734be00fab3a 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -45,6 +45,8 @@ static bool __is_cp_guaranteed(struct page *page)
 	if (inode->i_ino == F2FS_META_INO(sbi) ||
 			inode->i_ino ==  F2FS_NODE_INO(sbi) ||
 			S_ISDIR(inode->i_mode) ||
+			(S_ISREG(inode->i_mode) &&
+			is_inode_flag_set(inode, FI_ATOMIC_FILE)) ||
 			is_cold_data(page))
 		return true;
 	return false;
-- 
2.17.0.391.g1f1cddd558b5