udf: reduce stack usage of udf_get_filename

int udf_get_filename(struct super_block *sb, uint8_t *sname, uint8_t *dname,

		     int flen)

{

	struct ustr filename, unifilename;

	int len;

	struct ustr *filename, *unifilename;

	int len = 0;

	if (udf_build_ustr_exact(&unifilename, sname, flen))

	filename = kmalloc(sizeof(struct ustr), GFP_NOFS);

	if (!filename)

		return 0;

	unifilename = kmalloc(sizeof(struct ustr), GFP_NOFS);

	if (!unifilename)

		goto out1;

	if (udf_build_ustr_exact(unifilename, sname, flen))

		goto out2;

	if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) {

		if (!udf_CS0toUTF8(&filename, &unifilename)) {

		if (!udf_CS0toUTF8(filename, unifilename)) {

			udf_debug("Failed in udf_get_filename: sname = %s\n",

				  sname);

			return 0;

			goto out2;

		}

	} else if (UDF_QUERY_FLAG(sb, UDF_FLAG_NLS_MAP)) {

		if (!udf_CS0toNLS(UDF_SB(sb)->s_nls_map, &filename,

				  &unifilename)) {

		if (!udf_CS0toNLS(UDF_SB(sb)->s_nls_map, filename,

				  unifilename)) {

			udf_debug("Failed in udf_get_filename: sname = %s\n",

				  sname);

			return 0;

			goto out2;

		}

	} else

		return 0;

	len = udf_translate_to_linux(dname, filename.u_name, filename.u_len,

				     unifilename.u_name, unifilename.u_len);

	if (len)

		goto out2;

	len = udf_translate_to_linux(dname, filename->u_name, filename->u_len,

				     unifilename->u_name, unifilename->u_len);

out2:

	kfree(unifilename);

out1:

	kfree(filename);

	return len;

	return 0;

}

int udf_put_filename(struct super_block *sb, const uint8_t *sname,