eulerfs: add inode_operations for symlink inode

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I40JRR
CVE: NA

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Implement get_link, setattr and listxattr interfaces for symlink
inode operations.
Signed-off-by: NMingkai Dong <dongmingkai1@huawei.com>
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/eulerfs/symlink.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021. Huawei Technologies Co., Ltd. All rights reserved.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include "euler.h"
+
+static const char *eufs_get_link(struct dentry *dentry, struct inode *inode,
+				  struct delayed_call *call)
+{
+	struct eufs_inode *pi = EUFS_FRESH_PI(EUFS_PI(inode));
+
+	return ((char *)o2p(inode->i_sb, eufs_iread_root(pi))) + sizeof(u64);
+}
+
+const struct inode_operations eufs_symlink_inode_operations = {
+	.get_link = eufs_get_link,
+	.setattr = eufs_notify_change,
+};