The need for this change has been unveiled by configuring RobinHood delayed soft_rm feature, where HSM remove requests are submitted with no/Null archive_id, because RBH current version does not save archive_id infromation in its SOFT_RM DB table.
Since the corresponding files/FIDs have been fully unlinked, their Inodes/xattrs are no longer available in the name-space, and thus CDT is unable to retrieve the archive_id information by himself.
This leads to a situation where, without a copytool being registered to handle all/32 archive_ids, these HSM remove request can not be processed and will leak in archive.