Disclosed are systems, methods and apparatuses for managing objects (files and directories) in network file systems according to policies. Each policy may have one or more rules, each of which ties a condition to an action. Each condition can be expressed in terms of metadata harvested across file systems and stored in a metadata repository. The actions are user-programmable. Users can apply and/or enforce a policy by manipulating the metadata stored in the metadata repository. For example, suppose a policy prohibits storing MP3 files in corporate storage, a user can specify a rule that ties the condition “no MP3 files in volumes A-Z” to an action “delete MP3 files from volumes A-Z.” A file management application may apply a filter to the metadata repository to produce metadata records having values that meet the specified condition and take the corresponding action on managed objects associated with those metadata records.