reflink support and Samba running over XFS

[Jeremy Allison]

On Mon, Nov 07, 2022 at 10:47:48PM -0800, Christoph Hellwig wrote:
>On Mon, Nov 07, 2022 at 04:53:42PM -0800, Jeremy Allison via samba-technical wrote:
>> ret = ioctl(fsp_get_io_fd(dest_fsp), BTRFS_IOC_CLONE_RANGE, &cr_args);
>>
>> what ioctls are used for this in XFS ?
>>
>> We'd need a VFS module that implements them for XFS.
>
>That ioctl is now implemented in the Linux VFS and supported by btrfs,
>ocfs2, xfs, nfs (v4.2), cifs and overlayfs.

I'm assuming it's this:

https://man7.org/linux/man-pages/man2/ioctl_ficlonerange.2.html

Yeah ? I'll write some test code and see if I can get it
into the vfs_default code.