On Sun, May 06, 2018 at 09:16:41AM +1000, Dave Chinner wrote: > > In the patchset description [0], I ask if this should be the default > > feature (I think it should be) and holes should be converted to zeros as > > a special flag.. The only argument against it could be that applications > > are already using this interface, so this would be a change in behavior. > > In general, we don't change the behaviour of syscalls after the > fact. We have flags to control behaviour, so applications that want > to preserve holes will just have to be changed to use that flag. copy_file_range isn't documented to either preserve or not preserve holes. And in fact it will preserve holes (or even create new ones) for any filesystem that implements it as a clone like btrfs or xfs..
