Assigning a 4-byte extent list to a file

There are various versions of the structure of the catalog entry within the
LARGE_OBJECTS pubsets and in particular the extent list (3-byte and 4-byte variants). The user has no direct influence over which variant is assigned to a file. This happens implicitly via DMS, where a file is assigned a 4-byte extent list if:

• the size of the file exceeds the 32-GB limit, or

• the file is assigned an extent that is located on a volume with capacity >= 32 GB by the allocator.

4-byte extent lists are not converted back, even when the file becomes smaller than 32 GB or no longer has an extent on a large volume.