Re: [PATCH 3/4] NFSD: Add WRITE_PLUS support for hole punches

[Anna Schumaker <bjschuma@netapp.com>]

On 11/04/2013 01:53 PM, Christoph Hellwig wrote:
> On Mon, Nov 04, 2013 at 12:23:27PM -0500, Anna Schumaker wrote:
>>> state" that will return zeroes when read, even if those zeroes didn't
>>> make it to disk.
>>
>> And that's all done through metadata?  Doing the commit_metadata() call makes a bit more sense now.
> 
> Yes.  The only filesystem in tree that actually seems to write zeroes
> is gfs2, but even then it doesn't do so through the usual mechanisms.
> 
>>> Also what does the data arm buy us over good old WRITE?
>>>
>>
>> I've been working off of draft #21, the most recent commit is 2b3ab1740b1ea843faa59566fb4213a42d8c724a from Aug 19.  The eventual goal is to phase out WRITE and replace it with WRITE_PLUS, but that won't happen until at least 4.3.  I don't know why it's being done this way instead of just adding an FALLOCATE operation.
> 
> Where can I find draft 21?  The newest document in the git repo I was
> pointed to earlier is draft-ietf-nfsv4-minorversion2-13.txt, and the
> newest I could find on tools.ietf.org is draft 20.

You may need to run `make` in the NFSv4.2 directory.

> 
> I still don't understand why anyone would phase out WRITE in favour of
> something that doesn't actually add any value for the write case.
> 
> I'll try to take it up directly with the working group, but my post to
> the list yesterday in your SEEK thread didn't seem to have made it
> trough.   I also tried to research how they came up with this idiotic
> design, but the mailing list archives tell very little.  Could it be
> that most of these decisions are actually made in a smokey backroom and
> not on the list?
>