Explanation
Oracle Cloud Infrastructure File Storage service provides a durable, scalable, secure, enterprise-grade network file system. You can connect to a File Storage service file system from any bare metal, virtual machine, or container instance in your Virtual Cloud Network (VCN).
You can control the access of the file system from FSS by applying some security rules and others but the services it self not related to security but it related to shared storage

Explanation
A budget can be used to set soft limits on your Oracle Cloud Infrastructure spending. You can set alerts on your budget to let you know when you might exceed your budget, and you can view all of your budgets and spending from one single place in the Oracle Cloud Infrastructure console.
How Budgets Work:
Budgets are set on cost-tracking tags or on compartments (including the root compartment) to track all spending in that cost-tracking tag or for that compartment and its children.
All budgets alerts are evaluated every 15 minutes. To see the last time a budget was evaluated, open the details for a budget. You will see fields that show the current spend, the forecast and the "Spent in period" field which shows you the time period over which the budget was evaluated. When a budget alert fires, the email recipients configured in the budget alert receive an email.