From: Jim Meyering <jim@meyering.net>
To: Andi Kleen <andi@firstfloor.org>
Cc: "Pádraig Brady" <P@draigBrady.com>,
linux-btrfs@vger.kernel.org, bug-coreutils@gnu.org,
"Giuseppe Scrivano" <gscrivano@gnu.org>,
"Chris Mason" <chris.mason@oracle.com>
Subject: Re: BTRFS file clone support for cp
Date: Thu, 30 Jul 2009 12:16:48 +0200 [thread overview]
Message-ID: <87iqhatqzz.fsf@meyering.net> (raw)
In-Reply-To: <87ocr2frmx.fsf@basil.nowhere.org> (Andi Kleen's message of "Thu, 30 Jul 2009 11:26:46 +0200")
Andi Kleen wrote:
> Jim Meyering <jim@meyering.net> writes:
>>
>> Thanks. I haven't looked, but after reading about the reflink syscall
>> [http://lwn.net/Articles/332802/] had come to the same conclusion:
>> this feature belongs with ln rather than with cp.
>
> cp already has -l so it would make sense to extend that too.
Good point.
>> Besides, putting the new behavior on a new option avoids
>> the current semantic change we would otherwise induce in cp.
>
> I don't see how semantics change in a user visible way.
With classic cp, if I copy a 1GB non-sparse file and there's less
space than that available, cp fails with ENOSPC.
With this new feature, it succeeds even if there are
just a few blocks available.
Also, consider (buggy!) code that then depends on being able to modify
that file in-place, and that "knows" it doesn't need to check for ENOSPC.
Sure, they should always check for write failure, but still. It is
a change.
next prev parent reply other threads:[~2009-07-30 10:16 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87d47o3fip.fsf@master.homenet>
[not found] ` <4A6CEA48.5050208@draigBrady.com>
[not found] ` <8763defuvq.fsf@meyering.net>
[not found] ` <87ws5tvrq8.fsf@master.homenet>
2009-07-27 23:40 ` BTRFS file clone support for cp Pádraig Brady
2009-07-28 20:06 ` Giuseppe Scrivano
2009-07-29 13:01 ` Chris Mason
2009-07-29 14:14 ` Pádraig Brady
2009-07-29 16:10 ` Chris Mason
2009-07-29 16:18 ` Chris Mason
2009-07-29 18:14 ` Pádraig Brady
2009-07-30 0:57 ` Joel Becker
2009-07-30 7:39 ` Jim Meyering
2009-07-30 8:21 ` Joel Becker
2009-07-30 8:40 ` Pádraig Brady
2009-07-30 16:28 ` Ric Wheeler
2009-07-30 16:48 ` Jim Meyering
2009-07-30 9:26 ` Andi Kleen
2009-07-30 10:02 ` Pádraig Brady
2009-07-30 10:16 ` Jim Meyering [this message]
2009-07-30 10:21 ` Tomasz Chmielewski
2009-07-30 10:54 ` Andi Kleen
2009-07-30 18:05 ` Joel Becker
2009-07-30 23:28 ` Pádraig Brady
[not found] ` <87k51r9sxh.fsf@master.homenet>
[not found] ` <4A70C4E0.9030104@draigBrady.com>
2009-07-30 17:28 ` Giuseppe Scrivano
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