Re: [Xen-devel] [PATCH] public/io/blkif.h: make the comments on "sectors" self-consistent

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

> > I think this is how the currents implementations are working:
> >     media/disk size = "sectors" * "sector-size"
> > then, "sectors" and "sector-size" are never used again.
> 
> Not true, unfortunately. At least the Windows frontends are (mis)coded to use 
> sector numbers directly in blkif_request_t and blkif_request_segment rather 
> than re-scaling to 512 bytes, so setting sector-size != 512 will certainly 
> make them misbehave according to the protocol. This can, of course, be fixed 
> but I think we're at point where the only safe way to set a larger 
> sector-size would be to have the frontend write an 'I'm not broken' flag into 
> xenstore that the backend reads before setting sector-size (and if that means 
> that the backend has to do read-modify-write cycles for an underlying storage 
> device with a larger logical block size then so be it).

So, hard-coding "sector-size" to 512 in blkif.h sound good to me.

-- 
Anthony PERARD

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