ISGID
((DIP(dp, di_mode) & (ISGID | ISUID)) == 0 &&
ip->i_e2fs_mode &= ~(ISUID | ISGID);
if ((ip->i_e2fs_mode & ISGID) &&
ip->i_e2fs_mode &= ~ISGID;
if (!groupmember(ip->i_e2fs_gid, cred) && (mode & ISGID))
ip->i_e2fs_mode &= ~ISGID;
DIP_ASSIGN(ip, mode, DIP(ip, mode) & ~(ISUID | ISGID));
if ((DIP(ip, mode) & ISGID) &&
DIP_AND(ip, mode, ~ISGID);
if (!groupmember(DIP(ip, gid), cred) && (mode & ISGID))
DIP_AND(ip, mode, ~ISGID);