XFS_SYMLINK_BUF_SPACE
byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
byte_cnt = XFS_SYMLINK_BUF_SPACE(sc->mp, byte_cnt);