Dave, copy_file_range() is work under progress. FALLOC_FL_UNSHARE of fallocate() use case sounds interesting. I will try to address both of them in the next series.
Adding SCSI_XCOPY() support is not in the scope of this patchset. However blkdev_issue_copy() interface is made generic so that it is possible to extend to cross device XCOPY in future. Thanks, Selva
