f2fs: deny accessing encryption policy if encryption is off

This patch adds missing feature check in encryption ioctl interface.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -1928,6 +1928,9 @@ static int f2fs_ioc_set_encryption_policy(struct file *filp, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
 
+	if (!f2fs_sb_has_crypto(inode->i_sb))
+		return -EOPNOTSUPP;
+
 	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
 
 	return fscrypt_ioctl_set_policy(filp, (const void __user *)arg);
@@ -1935,6 +1938,8 @@ static int f2fs_ioc_set_encryption_policy(struct file *filp, unsigned long arg)
 
 static int f2fs_ioc_get_encryption_policy(struct file *filp, unsigned long arg)
 {
+	if (!f2fs_sb_has_crypto(file_inode(filp)->i_sb))
+		return -EOPNOTSUPP;
 	return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
 }