Re: VFS support for fast copy on deduplicating FSes

From: Pádraig Brady
Date: Thu Nov 25 2010 - 05:51:57 EST


On 25/11/10 10:32, Tomasz Torcz wrote:
> On Thu, Nov 25, 2010 at 04:19:17AM -0600, David Nicol wrote:
>> unresearched question/suggestion:
>>
>> Is there general support for a "fast copy" ioctl in the VFS layer,
>> which would be hooked by file systems that support COW or other forms
>> of deduplication and can provide copy semantics by manipulating
>> metadata only?
>>
>
> Yes, see reflink(2) syscall (http://lwn.net/Articles/331576/).
>

Yep and this: http://lwn.net/Articles/335380/
Note that cp --reflink has been supported for a while,
but it's BTRFS specific at the moment.
We'll need to change to the more generic interface.

cheers,
Pádraig.
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