Re: BTRFS file clone support for cp

[Jim Meyering]

Jim Meyering wrote:

> Jim Meyering wrote:
>
>> Andreas Schwab wrote:
>>
>>> Jim Meyering <address@hidden> writes:
>>>
>>>> +#ifdef __linux__
>>>> +# define BTRFS_IOC_CLONE 1074041865
>>>
>>> This is wrong, the actual value is architecture dependent.  You should
>>> use the _IOW macro instead.
>>
>> Good point.  Thanks!
>> I've adjusted it.
>> Here's the patch I'm considering now:
>>
>>>From 6ae1f09da25f6600f32dc540551a9479dd2e618e Mon Sep 17 00:00:00 2001
>> From: Giuseppe Scrivano <address@hidden>
>> Date: Sat, 25 Jul 2009 16:35:27 +0200
>> Subject: [PATCH] cp: support btrfs' copy-on-write file clone operation
>
> Giuseppe is going to write a root-only test to exercise this code,
> so I've made one final adjustment to his patch (move decl of "copied"
> down to definition) and have pushed this change:

Now that I've pushed that, I realize it deserves a NEWS entry:

>From 722d75b6091dd55b9254e7a49727ebe2f97d00a7 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Wed, 29 Jul 2009 12:25:33 +0200
Subject: [PATCH] maint: update NEWS

* NEWS (New features): Mention it.
---
 NEWS |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/NEWS b/NEWS
index e476f2b..80c60e2 100644
--- a/NEWS
+++ b/NEWS
@@ -35,6 +35,9 @@ GNU coreutils NEWS                                    -*- 
outline -*-

   chroot now accepts the options --userspec and --groups.

+  cp, install, mv: take advantage of btrfs' O(1) copy-on-write feature
+  when both the source and destination are on the same btrfs partition.
+
   sort accepts a new option, --human-numeric-sort (-h): sort numbers
   while honoring human readable suffixes like KiB and MB etc.

--
1.6.4.rc3.201.gd9d59