can't we simply ignore all directories named '.zfs', i.e. "--exclude=.zfs" ?
> + # exclude snapdir if disk is on zfs
> + if ($self->$disk_on_zfs($disk)) {
> + push @exclude_zfs_snapdir, $disk->{mp} eq '/' ? "--exclude=./.zfs" :
> "--exclude=.$disk->{mp}/.zfs";