Access Control Lists

The Ext2 filesystem provides support for Access Control Lists (ACL), although they are not fully used. ACLs basically consist of a list of resources for which users of a system give requests for access. Accesses are of three types: Read, Write and Execute. Control Lists store the permissions for each resource for each user of those resources. Any access to the resources is granted only after checking with the Access Control List. Once permitted, the ACL provides mutual exclusion for resources, although it may allow read/share access depending on the policies.