Aspects of the subject matter described herein relate to tracking file system namespace changes during transactions. In aspects, a filter monitors operations that may affect a tracked portion of a transactional file system's namespace. When an operation that affects the tracked portion is received, a data structure is modified to track the changes. Nodes within the data structure are marked to indicate whether they can be seen inside or outside of the transaction. If the transaction commits or rolls back, nodes within the data structure are deleted and made visible as appropriate.