linux how to do bind mount

iscsi LUN is mounted to /netapp

a)
bind mount /netapp to /var/lib/nova/instances
$sudo mount --bind /netapp /var/lib/nova/instances

b)
Find bind mount
$ df -a
/dev/sdb1      1056777312 1160760 1001912260   1% /netapp
/dev/sdb1      1056777312 1160760 1001912260   1% /var/lib/nova/instances

c)