Re: [fuse-devel] Clone-file via FUSE

[Shachar S. <syn...@gm...>]

Hi Nikolaus,
Thank you for your reply.
Could you please specify the key/value arguments you use in your
solution? I am asking for those details because I do not want to
compromise security in favor of usability.

Thanks in advance,
- Shachar.

On Fri, Jun 6, 2014 at 3:44 AM, Nikolaus Rath <Nik...@ra...> wrote:
> Shachar Sharon <syn...@pu...> writes:
>> Hi all,
>> I want to implement file-cloning for FUSE based file system (use-case:
>> multiple vms which share single golden-image).
>>
>> Unfortunately, btrfs' ioctl solution, used by coreutils to implement 'cp
>> --reflink...', will not work properly for FUSE
>> (
>> http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=45330176690b079ed47ac7c58f29a1b028f97b07
>> )
>>
>> Did anyone implement such functionality for FUSE based file-system, via
>> ioctl or in any other way? What arguments did he pass over to the
>> server?
>
> I implemented it with extended attributes. Cloning is achieved by
> setting two special extended attributes on a hidden file at the root of
> the mountpoint to the inode of the source and destination. That means
> you can't use cp --reflink though, I'm providing a separate command
> (that could fall back to cp --reflink when used on a different file
> system).
>
>
> Best,
> -Nikolaus
>
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