As discussed on samba-technical, the existing clone-range behaviour should be moved out of vfs_btrfs and into vfs_default. The once btrfs specific BTRFS_IOC_CLONE_RANGE ioctl is now supported by multiple Linux filesystems as generic IOC_CLONE_RANGE ioctl.

On Thu, 4 May 2017 08:58:10 -0700, Christoph Hellwig wrote:

> On Thu, May 04, 2017 at 05:54:41PM +0200, David Disseldorp wrote:
> > On Thu, 4 May 2017 08:40:00 -0700, Christoph Hellwig wrote:
> >
> > > Not directly related to the patch, but IOC_CLONE_RANGE is a core
> > > VFS feature in Linux these days and for example support by XFS and NFS
> > > as well.  It's somewhat odd to have it in a vfs_btrfs module.
> >
> > Yeah, this'll hopefully get moved out of vfs_btrfs soon. A WIP
> > syscall(SYS_copy_file_range) patch from Björn is available at:
> > https://lists.samba.org/archive/samba-technical/2017-January/118259.html
>
> Don't use copy_file_range if you want to clone.  IOC_CLONE_RANGE is
> always the better choice if supported.