From eb44d8769b495f2b8e6a2ae9eae340bc675c2c04 Mon Sep 17 00:00:00 2001
From: Chao Yu <yuchao0@huawei.com>
Date: Thu, 25 Jul 2019 22:39:11 +0800
Subject: [PATCH] f2fs: disallow direct IO in atomic write

Atomic write needs page cache to cache data of transaction,
direct IO should never be allowed in atomic write, detect
and deny it when open atomic write file.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 52d5f0745b8a..4d20bff7c075 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1836,6 +1836,9 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
 	if (!S_ISREG(inode->i_mode))
 		return -EINVAL;
 
+	if (filp->f_flags & O_DIRECT)
+		return -EINVAL;
+
 	ret = mnt_want_write_file(filp);
 	if (ret)
 		return ret;