A computer configured by a file system to manage storage of and access to a plurality of file system objects on one or more storage devices, the computer comprising: a storage medium configured to store data, the data indicating whether stored data on the one or more storage devices are shared by file system objects; a processing system comprising a memory and a processor, with computer program code stored in the memory that, when executed by the processor, configures the processing system to: respond to requests from applications to access file system objects on the one or more storage devices; in response to a request to write data to a file system object, determine whether the file system object shares stored data with other file system objects based on at least the data stored on the storage medium; in response to a determination that the file system object shares stored data, write the data to a new extent for the file system object in the one or more storage devices and update the data indicating whether the stored data on the one or more storage devices are shared; and in response to a request to rearrange desired data of a source file system object, identify the desired data to be copied from the source file system object; create a destination file system object by ordering the identified data in the destination file system object in a desired order based on the request and referencing storage locations on the one or more storage devices of the identified data of the source file system object, and update the data indicating that the data in the storage locations on the one or more storage devices are shared by the source and destination file system objects. a storage medium configured to store data, the data indicating whether stored data on the one or more storage devices are shared by file system objects; a processing system comprising a memory and a processor, with computer program code stored in the memory that, when executed by the processor, configures the processing system to: respond to requests from applications to access file system objects on the one or more storage devices; in response to a request to write data to a file system object, determine whether the file system object shares stored data with other file system objects based on at least the data stored on the storage medium; in response to a determination that the file system object shares stored data, write the data to a new extent for the file system object in the one or more storage devices and update the data indicating whether the stored data on the one or more storage devices are shared; and in response to a request to rearrange desired data of a source file system object, identify the desired data to be copied from the source file system object; create a destination file system object by ordering the identified data in the destination file system object in a desired order based on the request and referencing storage locations on the one or more storage devices of the identified data of the source file system object, and update the data indicating that the data in the storage locations on the one or more storage devices are shared by the source and destination file system objects. respond to requests from applications to access file system objects on the one or more storage devices; in response to a request to write data to a file system object, determine whether the file system object shares stored data with other file system objects based on at least the data stored on the storage medium; in response to a determination that the file system object shares stored data, write the data to a new extent for the file system object in the one or more storage devices and update the data indicating whether the stored data on the one or more storage devices are shared; and in response to a request to rearrange desired data of a source file system object, identify the desired data to be copied from the source file system object; create a destination file system object by ordering the identified data in the destination file system object in a desired order based on the request and referencing storage locations on the one or more storage devices of the identified data of the source file system object, and update the data indicating that the data in the storage locations on the one or more storage devices are shared by the source and destination file system objects. identify the desired data to be copied from the source file system object; create a destination file system object by ordering the identified data in the destination file system object in a desired order based on the request and referencing storage locations on the one or more storage devices of the identified data of the source file system object, and update the data indicating that the data in the storage locations on the one or more storage devices are shared by the source and destination file system objects.