A file system that does not conflate item lifetime with the item's inclusion in an organizational structure of the file system is described herein. In addition, the file system's organizational structure is not limited to directory trees, but instead may use any directed acyclic graph (DAG). Items, once stored into the file system, may be maintained until affirmatively deleted by a client of the file system, regardless of whether the item is part of a DAG or not. Items may be placed in file regions, which are conceptual workspaces for a client to control item lifetime and to organize items into any DAG structure of the user's choosing. Items may be concurrently stored in multiple DAGs, and each file region may have one or more independent DAGs. An item's placement in a DAG may also be used to govern file properties such as namespace, security, privacy, and read/write attributes.