A clone splitting technique enables efficient online splitting of blocks shared between a parent virtual volume (vvol) and a clone in accordance with a shared block splitting procedure executing on a storage system. Online splitting of shared blocks denotes allowing execution of read/write operations directed to the clone, as well as to the parent vvol, as the shared blocks are split. The clone splitting technique removes any connection between a clone and its parent vvol, thereby allowing the clone to be used as a first-class volume. Moreover, the technique removes such connection while allowing both the clone and parent vvol to remain available online and writeable (accessible) to clients during the shared block splitting procedure.