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>

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1e27b4bc852d8412bdc765a4735cb2b81cfe66be..a5080bea6b0b439b2e6d583be8c63bc32da8c0b2 100644 (file)
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1825,6 +1825,9 @@ 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;