MNT_UMOUNT
if (!(mnt->mnt_parent->mnt.mnt_flags & MNT_UMOUNT))
p->mnt.mnt_flags |= MNT_UMOUNT;
if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
m->mnt.mnt_flags |= MNT_UMOUNT;
return m->mnt.mnt_flags & MNT_UMOUNT;