OVL_XATTR_ESCAPE_PREFIX_LEN
res -= OVL_XATTR_ESCAPE_PREFIX_LEN;
name_len = slen - prefix_len - OVL_XATTR_ESCAPE_PREFIX_LEN;
memmove(s, s + OVL_XATTR_ESCAPE_PREFIX_LEN, name_len + len);
escaped_len = prefix_len + OVL_XATTR_ESCAPE_PREFIX_LEN + name_len;
memcpy(s, OVL_XATTR_ESCAPE_PREFIX, OVL_XATTR_ESCAPE_PREFIX_LEN);
s += OVL_XATTR_ESCAPE_PREFIX_LEN;