Re: [PATCH v2 0/3] NFSD: Implement SEEK

From: Anna Schumaker <bjschuma@netapp.com>
To: "J. Bruce Fields" <bfields@fieldses.org>,
	Christoph Hellwig <hch@infradead.org>
Cc: <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH v2 0/3] NFSD: Implement SEEK
Date: Wed, 13 Nov 2013 12:07:43 -0500	[thread overview]
Message-ID: <5283B1DF.1020007@netapp.com> (raw)
In-Reply-To: <20131113164959.GL28033@fieldses.org>

On 11/13/2013 11:49 AM, J. Bruce Fields wrote:
> On Wed, Nov 13, 2013 at 08:15:27AM -0800, Christoph Hellwig wrote:
>> On Wed, Nov 13, 2013 at 11:07:19AM -0500, Anna Schumaker wrote:
>>> I'm thinking something like this:
>>
>> Given that the whole sparse file support seems more experimental than
>> the security labels requiring the former for the latter seems a bit odd.
>>
>> I have to admit that I don't really know how to deal with those changes,
>> on the one hand I'd love to expose it as soon as possible, on the other
>> hand the spec has so many higher level flaws related to their concepts
>> of sparse files that I'd feel really bad about locking even parts of it
>> in at the moment.
> 
> This isn't a candidate for 3.13, and SEEK didn't look like the most
> problematic bit, so with a couple more months I'm hoping we'll be more
> confident about the protocol?
> 
> Actually now that I look, I forget: even if security labels are built
> in, 4.2 is still off by default at runtime for now.
> 
> We could add another interface to toggle individual features at run time
> but I think that's definitely too complicated.
> 
> Maybe:
> 
> 	- keep 4.2 off by default a runtime for now.
> 	- keep each feature under its individual config option:
> 	  NFSD_V4_SECURITY_LABEL, NFSD_V4_SEEK, NFSD_V4_SEND_PONIES....
> 	- when an individual feature matures, ditch its config option
> 	  and build it unconditionally.  We're always getting little
> 	  build bugs due to untested build options so I'd rather not
> 	  keep them around indefinitely.
> 	- once 4.2 has at least one feature that we think is mature
> 	  enough, switch the runtime 4.2 default to on and depend on
> 	  scary warnings on the remaining build options to keep people
> 	  from exposing them in production.
> 
> ?

That's doable too.  And it keeps me from having to touch security label code that I don't know a whole lot about!

Anna

> 
> --b.
> 