Grafana tables available diskspace for some folders

Hi,

I use Prometheus with the node_exporter added the query to monitor available diskspace.

100 - ((node_filesystem_avail_bytes{instance=~"$node:$port",job=~"$job",device!~‘rootfs’} * 100) / node_filesystem_size_bytes{instance=~"$node:$port",job=~"$job",device!~‘rootfs’})

This give me multiple mounts such as /home /tmp et cetera.

My question: How can I modify the quesry so onle /tmp is monitored for example.