Contains a map of the logical extents being used on the volume and shows how fragmented a file is.
typedef struct zLogicalExtentElement_s { QUAD blockNumber; QUAD numBlocks; } zLogicalExtentElement_s;
Specifies the logical block number in the volume where this extent starts. If this field contains FILEMAP_SPARSEBLOCK, this is an extent that describes an unallocated or sparse section of the file.
Specifies the number of logically contiguous blocks in this extent.
Each extent element identifies a different fragment of the file on the logical volume. All fragments, including sparse ones, are represented by an extent.