Subject: bug#23904: Btrfs clone support in copy operations

From: Eli Zaretskii <[email-masked]>
Date: Wed, 06 Jul 2016 17:58:15 +0300

> From: Paul Eggert <[email-masked]>
> Date: Wed, 6 Jul 2016 13:48:26 +0200
> Cc: [email-masked], Kieran Colford <[email-masked]>
> 
> Revised patch attached. Basically untested, since I don't use any file 
> systems that support FIOCLONERANGE. The patch still has FIXMEs for what 
> happens if the FIOCLONERANGE ioctl is interrupted by a signal, and for a 
> good clone chunk size (the patch guesses 1 GiB).

Thanks.

However, I wonder: are we sure users will always want this
unconditionally, completely out of their control?  Does 'cp' from
Coreutils do the same unconditionally, for example?