[RFC] Remove requirement of alignment to track from MBR scheme

[Andrey V. Elsukov]

On 24.05.2011 22:12, Marcel Moolenaar wrote:
> 
> On May 24, 2011, at 10:46 AM, Warner Losh wrote:
>>> All I'm saying: be careful.
>>
>> Agreed.  But the care should be on the creation side, not on the interpretation side.
> 
> ... as the original code was. We just need to add a sanity
> check to the interpretation that filters out the real bogus
> information (resulting in a partition with negative size).

A partition with negative size is not the one problem.
Some time ago i found an easy reproducible bug, when BSD scheme
creates providers with size bigger than parent provider size.
Also  there was nothing against creation of overlapped partitions.

> With respect to the creation:
> 
> Since out synthesized geometry is not necessarily the same
> as other OSes, we could opt to synthesize a geometry that
> has a track size (= sectors/track) that is a multiple of 8
> (to play nice with 4K sectors), and/or take the stripe
> size of the underlying GEOM into account. This fundamentally
> doesn't change a thing for MBR, but has the side effect of
> achieving some of the goals *and* automatically works for
> EBR as well.

Today's devices do not report about their 4k sectors.

> Thus: rather than hack MBR and forgetting about EBR and other

I do not forget about EBR, PC98 and VTOC8. But we need begin from something.

> schemes, maybe we only have to tweak the geometry synthesis
> to give people what they want without going over board. After
> 9.0 branched, we can do a lot more knowing we have plenty
> of soak time...

Ok, i can revert all related changes and just do nothing :)
It seems it is better solution :)

-- 
WBR, Andrey V. Elsukov

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