Re: [Qemu-block] [Qemu-devel] [PATCH v2 1/3] block: Extrace bdrv_parse_detect_zeroes_flags

[Fam Zheng]

On Wed, 06/10 17:11, Fam Zheng wrote:
> On Mon, 06/08 16:53, Paolo Bonzini wrote:
> > 
> > 
> > On 08/06/2015 16:17, Eric Blake wrote:
> > >> > +
> > >> > +    if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
> > >> > +        !(bdrv_flags & BDRV_O_UNMAP)) {
> > >> > +        error_setg(errp, "setting detect-zeroes to unmap is not 
> > >> > allowed "
> > >> > +                         "without setting discard operation to 
> > >> > unmap");
> > >> > +    }
> > > I think it might be better to have a tri-state enum, than to have two
> > > competing bools where only 3 of the 4 states are valid.
> > 
> > Note that this is not a bool.  We have one bool and one 3-element enum
> > (off/on/unmap), where only 5 of the 6 states are valid.  Also, at least
> > detect-zeroes would go away if we had some kind of blockdev-mirror
> > (where the target is added first with blockdev-add), so I think it's
> > better to leave it separate.
> 
> Agreed. But by then "drive-mirror derive=... detect-zeroes=unmap unmap=false"

s/derive/device/

> will be way too confusing.
> 
> I say let's save that and just go for blockdev-add :)
> 
> https://www.mail-archive.com/address@hidden/msg301990.html
> 
> Fam
>