Patent ID: 9251049
Filing Date: 2016-02-02
CPC Classification: G06F

Claim Text:
1. A process of determining explicitly free data storage space in data storage subsystem that is implicitly allocated to a host file system, comprising the steps of: querying the host file system to identify file system storage units that are no longer in use by the host file system, wherein the file system storage units correspond to implicitly allocated storage space in the data storage subsystem by virtue of the file system storage units having been previously allocated to the host file system, resulting in such allocated storage space being free for reuse in actuality yet still appearing, from the perspective of the data storage subsystem, as in use by the host file system; receiving a list of the identified unused file system storage units from the host file system; mapping each unused file system storage unit of the list of identified unused file system storage units to a correspondingly implicitly allocated data storage space in the data storage subsystem; and explicitly freeing the corresponding implicitly allocated data storage space, such that the explicitly free data storage space no longer appears in use by the host file system from the perspective of the data storage subsystem.