f2fs: switch to fscrypt_get_symlink()

static void *f2fs_encrypted_follow_link(struct dentry *dentry,

						struct nameidata *nd)

{

	struct page *cpage = NULL;

	char *caddr, *paddr = NULL;

	struct fscrypt_str cstr = FSTR_INIT(NULL, 0);

	struct fscrypt_str pstr = FSTR_INIT(NULL, 0);

	struct fscrypt_symlink_data *sd;

	struct inode *inode = d_inode(dentry);

	u32 max_size = inode->i_sb->s_blocksize;

	int res;

	res = fscrypt_get_encryption_info(inode);

	if (res)

		return ERR_PTR(res);

	cpage = read_mapping_page(inode->i_mapping, 0, NULL);

	if (IS_ERR(cpage))

		return ERR_CAST(cpage);

	caddr = kmap(cpage);

	/* Symlink is encrypted */

	sd = (struct fscrypt_symlink_data *)caddr;

	cstr.name = sd->encrypted_path;

	cstr.len = le16_to_cpu(sd->len);

	/* this is broken symlink case */

	if (unlikely(cstr.len == 0)) {

		res = -ENOENT;

		goto errout;

	}

	if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > max_size) {

		/* Symlink data on the disk is corrupted */

		res = -EIO;

		goto errout;

	}

	res = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr);

	if (res)

		goto errout;

	res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr);

	if (res)

		goto errout;

	/* this is broken symlink case */

	if (unlikely(pstr.name[0] == 0)) {

		res = -ENOENT;

		goto errout;

	}

	struct page *page;

	void *target;

	paddr = pstr.name;

	if (!dentry)

		return ERR_PTR(-ECHILD);

	/* Null-terminate the name */

	paddr[pstr.len] = '\0';

	nd_set_link(nd, paddr);

	page = read_mapping_page(inode->i_mapping, 0, NULL);

	if (IS_ERR(page))

		return ERR_CAST(page);

	kunmap(cpage);

	page_cache_release(cpage);

	return NULL;

errout:

	fscrypt_fname_free_buffer(&pstr);

	kunmap(cpage);

	page_cache_release(cpage);

	return ERR_PTR(res);

	target = fscrypt_get_symlink(inode, page_address(page),

				     inode->i_sb->s_blocksize, nd);

	put_page(page);

	return target;

}

const struct inode_operations f2fs_encrypted_symlink_inode_operations = {