Messages in this thread | | | Date | Mon, 13 Jan 2014 21:11:33 -0500 | From | Boris Ostrovsky <> | Subject | Re: [PATCH] xen-blkfront: remove type check from blkfront_setup_discard |
| |
On 01/13/2014 06:07 PM, Olaf Hering wrote: > On Mon, Jan 13, Boris Ostrovsky wrote: > >> On 01/13/2014 04:30 AM, Olaf Hering wrote: >>>> Similarly, if xenbug_gather("discard-secure") fails, I think the code will >>>> assume that secure discard has not been requested. I don't know what >>>> security implications this will have but it sounds bad to me. >>> There are no security implications, if the backend does not advertise it >>> then its not present. >> Right. But my questions was what if the backend does advertise it and wants >> the frontent to use it but xenbus_gather() in the frontend fails. Do we want >> to silently continue without discard-secure? Is this safe? > The frontend can not know that the backend advertised discard-secure > because the frontend just failed to read the property which indicates > discard-secure should be enabled.
And is it OK for the frontend not to know about this?
I don't understand what the use model for this feature is. Is it just that the backend advertises its capability and it's up to the frontend to use it or not -or- is it that the user/admin created the storage with expectations that it will be used in "secure" manner.
I think if it's the former then losing information about storage features is OK but if it's the latter then I am not so sure.
Or perhaps it's neither of these two and I am completely missing the point of this feature.
-boris
| |