RE: [Xen-devel][PATCH]ioemu:

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

Zhang, Yang writes ("RE: [Xen-devel][PATCH]ioemu:"):
> [Ian:]
> >However I agree that passing BDRV_O_CACHE_WB, to disable O_DSYNC,
> >would be correct at least for the non-stubdom case.  Does O_DSYNC even
> >have any effect in stubdom ?  I would have expected not.
>
> I doesn't test if it is effect in stubdom. May be you are right. I
> should not change it in stubdom

I think it is better to be consistent in the two cases.  Not passing
O_DSYNC should be harmless in stubdom I think.

> >Why did you set BDRV_O_RDONLY as well ?  [...]
>
> The arg default is zero. And I see the BDRV_O_RDONLY is defined as
> zero too in "block.h". So I think I can change the zero to
> BDRV_O_RDONLY.

Oh, I see.  No, that's not what zero means.  In fact BDRV_O_RDONLY is
broken; I had remembered there was a problem here but I didn't look at
the definition to check to see how your code could possibly work,
before emailing you.  Sorry.

> There are nothing different in essentially. But I think you are
> right. I should only add the BDRV_O_CACHE_WB.

I have commited a change to do this.

Ian.

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