1. A method for controlling access to file system objects, comprising: in a network having a plurality of machines running networked file systems, implementing an access control system on a server computer, the access control system being communicatively connected to a metadata repository storing metadata associated with objects in the file systems, the metadata including a plurality of classification tags, each of the plurality of classification tags being stored in the metadata repository in association with an object as a result of an evaluation of an expression in a classification, the classification being stored in a classification repository communicatively connected to the access control system; in response to a request for a user to access a file system in the network, the access control system determining a user identifier associated with the user and an object identifier corresponding to each of one or more objects in the file system that the user is requesting access; the access control system determining a first set of classification tags that the user associated with the user identifier is authorized to access; the access control system determining, from the plurality of classification tags, a second set of classification tags associated with the object identifier corresponding to the each of the one or more objects in the file system that the user is requesting access; the access control system determining if the user is authorized to access the file system by comparing each of the first set of classification tags that the user associated with the user identifier is authorized to access with the second set of classification tags associated with the one or more objects in the file system that the user is requesting access; and the access control system controlling access of the user to the one or more objects in the file system that the user is requesting access based upon a result of the comparing.