Extending cluster allocations in an extensible file system

摘要

An extensible file system format for portable storage media is provided. The extensible file system format includes the specification of primary and secondary directory entry types that may be custom defined. The primary and secondary directory entry types can be further classified as critical and benign directory entries. The directory entry types can define whether a cluster chain corresponding to a file can be contiguously allocated.

主权项

1. A method, comprising:
obtaining a request for an extension of a plurality of clusters, the plurality of clusters comprising a cluster chain of two or more clusters stored contiguously, the extension comprising an additional allocation of one or more clusters to the cluster chain; determining that the extension and the plurality of clusters are not contiguously allocatable; allocating an entry in a file allocation table for each of the clusters of the plurality of clusters; setting a flag to indicate that the plurality of clusters are not contiguously allocated; allocating an entry in the file allocation table for each of the clusters of the extension; and updating an allocation bitmap to indicate the allocation of the clusters for the plurality of clusters and the extension.