How to use empty disk spaces under /dev/sdb1 on Azure?

I have a VM with 200GB local SSD on Windows Azure.

When I want to use 100GB of it, a "Disk Quote Exceed Error" message is appeared. I can see that my home ( or root) directory is 30GB from the table below ( which is output of df -Th )

So how can I make the disk space /dev/sdb1 available to use in my home directory?

Filesystem    Type      Size  Used Avail Use% Mounted on------------------------------------------------------------udev           devtmpfs  6.9G     0  6.9G   0% /devtmpfs          tmpfs     1.4G  8.6M  1.4G   1% /run/dev/sda1      ext4       30G  1.6G   28G   6% /tmpfs          tmpfs     6.9G     0  6.9G   0% /dev/shmtmpfs          tmpfs     5.0M     0  5.0M   0% /run/locktmpfs          tmpfs     6.9G     0  6.9G   0% /sys/fs/cgroup/dev/sdb1      ext4      197G   60M  187G   1% /mnttmpfs          tmpfs     1.4G     0  1.4G   0% /run/user/1000