On 1/7/14, 2:01 PM, Ben Myers wrote:
> Hey Gents,
>
> On Mon, Jan 06, 2014 at 03:46:58PM -0600, Eric Sandeen wrote:
>> On 1/6/14, 3:42 PM, Josef Bacik wrote:
>>>
>>> On 01/06/2014 04:32 PM, Eric Sandeen wrote:
>>>> On 1/6/14, 1:58 PM, Josef Bacik wrote:
>>>>> I was trying to reproduce something with fsx and I noticed that no matter
>>>>> what
>>>>> seed I set I was getting the same file. Come to find out we are
>>>>> overloading
>>>>> random() with our own custom horribleness for some unknown reason. So
>>>>> nuke the
>>>>> damn thing from orbit and rely on glibc's random(). With this fix the -S
>>>>> option
>>>>> actually does something with fsx. Thanks,
>>>> Hm, old comments seem to indicate that this was done <handwave> to make
>>>> random
>>>> behave the same on different architectures (i.e. same result from same
>>>> seed,
>>>> I guess?) I . . . don't know if that is true of glibc's random(), is it?
>>>>
>>>> I'd like to dig into the history just a bit before we yank this, just to
>>>> be sure.
>>>
>>> I think that if we need the output to match based on a predictable
>>> random() output then we've lost already. We shouldn't be checking for
>>> specific output (like inode numbers or sizes etc) that are dependant
>>> on random()'s behaviour, and if we are we need to fix those tests. So
>>> even if that is why it was put in place originally I'd say it is high
>>> time we ripped it out and fixed up any tests that rely on this
>>> behaviour. Thanks,
>>
>> Yeah, you're probably right. And the ancient xfstests history seems to
>> be lost in the mists of time, at least as far as I can see. So I'm ok
>> with this but let's let Dave & SGI chime in too just to be certain.
>
> I did not have success locating the history prior to what we have posted on
> oss. I agree that it was likely added so that tests that expose output from
> random into golden output files will have the same results across arches.
> Maybe this is still of concern for folks who use a different c library with
> the
> kernel.
>
> Looks there are quite a few callers. IMO if we're going to remove this we
> should fix the tests first.
Or first, determine if they really need fixing. Did you find tests which
actually contain the random results in the golden output?
-Eric
> -Ben
>
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