Coordinating a reclaiming of data storage space among processing nodes of a data storage system includes, by a first node in response to an event, performing local cleanup of first-node mapping data and issuing a request message to a second node, the request message identifying the data storage space to be reclaimed. The event may be a notification from a RAID component rebuilding a RAID volume. In response to the request message, the second node performs local cleanup of second-node mapping data and issues a completion message to the first node indicating that the second node has completed its part of the reclaiming of the data storage space. The first node responds to the completion message by marking the data storage space as being reclaimed and signaling to a source of the event that the data storage space is available for new use.