[PATCH] copy_file_range: New function to copy file data

[Florian Weimer]

On 11/17/2017 03:56 PM, Florian Weimer wrote:
> 	* io/tst-copy_file_range.c: Likewise.

The test depends on TEST_COMPARE from the MPK patch.

> 	* support/Makefile (libsupport-routines): Add support-xfstat,
> 	support_enter_mount_namespace, xftruncate, xlseek.
> 	* support/namespace.h (support_enter_mount_namespace): Declare.
> 	* support/support-xfstat.c: New file.
> 	* support/support_enter_mount_namespace.c: Likewise.
> 	* support/xftruncate.c: Likewise.
> 	* support/xlseek.c: Likewise.

As usual, I can commit the support/ additions separately if this is 
desirable.

Thanks,
Florian