linux-kernel - [PATCH] f2fs: disallow direct IO in atomic write

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Date:   Thu, 25 Jul 2019 22:39:11 +0800
From:   Chao Yu <chao@...nel.org>
To:     jaegeuk@...nel.org
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Chao Yu <yuchao0@...wei.com>,
        Gao Xiang <gaoxiang25@...wei.com>
Subject: [PATCH] f2fs: disallow direct IO in atomic write

From: Chao Yu <yuchao0@...wei.com>

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@...wei.com>
Signed-off-by: Chao Yu <yuchao0@...wei.com>
---
 fs/f2fs/file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 43d878f3db0f..34de73be2cc9 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1842,6 +1842,9 @@ 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;
-- 
2.22.0