[OpenAFS-devel] Making supergroups default to on

[Jason Edgecombe]

On 12/28/2012 05:22 PM, Jason Edgecombe wrote:
> On 12/28/2012 03:33 PM, Simon Wilkinson wrote:
>> On 28 Dec 2012, at 19:20, Andrew Deason wrote:
>>> I'm not sure if that's really an absolute requirement, though. The 
>>> 'code
>>> quality issues' that I remember were just the opinions of a few people
>>> that would make them uneasy about turning it on. I don't recall anyone
>>> trying very hard to get the default changed, so maybe that's all it
>>> takes.
>> There were/are a number of different issues in the supergroups code. 
>> There are aliasing issues throughout, some of which could be easily 
>> fixed by inserting memcpy's rather than just using casts/assignments, 
>> but there are others that require far more in depth analysis. This 
>> second set of aliasing problems are mainly confined to the caching 
>> code, rather than the supergroups code itself. It would certainly be 
>> possible to either disable caching, or rework that code, whilst 
>> having the ubik database format remain unchanged.
>>
>> The other major issue is that there is bit twiddling in the caching 
>> code which makes assumptions about endianness, and about word size. I 
>> think we have now caught all of these problems - but certainly with 
>> the 1.4 series you couldn't safely run supergroups on a 64 bit machine.
>>
> That's slightly unsettling. We're running supergroups-enabled cell 
> servers on 64bit RHEL5, albeit with YFS modifications.
>
> My main desire is to reduce the number of conditional features to 
> reduce code rot and extra ongoing development/testing efforts.
>
> Jason

1.4.X, that is.