This implements the Linux VFS ops required to service the file
copy/clone APIs:
.copy_file_range (4.5+)
.clone_file_range (4.5-4.19)
.dedupe_file_range (4.5-4.19)
.remap_file_range (4.20+)
Note that dedupe_file_range() and remap_file_range(REMAP_FILE_DEDUP) are
hooked up here, but are not implemented yet.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Kay Pedersen <mail@mkwg.de>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Sponsored-By: OpenDrives Inc.
Sponsored-By: Klara Inc.
Closes#15050
