Managing capacity of a thinly provisioned storage system

A computer-implemented process comprising:

• receiving, by a file system of a computer, a request to allocate storage for a file in a storage system accessible by the computer, wherein the storage system comprises a thinly provisioned storage system comprising a plurality of storage devices;
• in response to the request to allocate storage for a file,
• determining whether virtual storage space is available in the thinly provisioned storage system for the file using an allocation map stored in a storage medium and associating files with virtual storage locations;
• in response to a determination that virtual storage space is available for the file,
• reserving the virtual storage space for the file in the allocation map, and
• determining whether actual physical storage space is available among the plurality of storage devices in the storage system for the reserved virtual storage space using a thin provisioning map stored in a storage medium and associating virtual storage locations with actual physical storage locations;
• in response to a determination that actual physical storage space is available for the file, reserving the actual physical storage space for the file and associating the actual physical storage space with the virtual storage space reserved for the file in the thin provisioning map.

An article of manufacture comprising:

• a computer storage medium comprising at least one of a memory and a storage device;
• computer program instructions stored on the computer storage medium which, when processed by a processing system, instruct the processing system to perform a process comprising:
• receiving a request to allocate storage for a file in a thinly provisioned storage system comprising a plurality of storage devices;
• in response to the request to allocate storage for a file,
• determining whether virtual storage space is available in the thinly provisioned storage system for the file using an allocation map stored in a storage medium and associating files with virtual storage locations;
• in response to a determination that virtual storage space is available for the file,
• reserving the virtual storage space for the file in the allocation map, and
• determining whether actual physical storage space is available among the plurality of storage devices for the reserved virtual storage space using a thin provisioning map stored in a storage medium and associating virtual storage locations with actual physical storage locations;
• in response to a determination that actual physical storage space is available for the file, reserving the actual physical storage space for the file and associating the actual physical storage space with the virtual storage space reserved for the file in the thin provisioning map.