Am 12.02.2018 um 15:32 hat Paolo Bonzini geschrieben: > On 12/02/2018 15:30, Kevin Wolf wrote: > >>> We shouldn't be adding new instances of BLOCK_OP_* at all. I couldn't > >>> find the time yet to remove the existing ones, but any new protections > >>> should be using the permission system. > >> I agree. But does this include not fixing bugs wherever clients are > >> using the old op blockers? > > I'm not saying that we shouldn't fix the bug, just that we should fix it > > properly with the best infrastructure we have. > > > > The old op blockers are "fixing" the problem at the symptom level, and > > you have to check for each high-level operation if it does something > > problematic internally. You have to repeat this analysis every time you > > add a new operation or modifiy an existing one (which noone ever does). > > The risk that this breaks sooner or later is pretty high. > > > > The new permission system, on the other hand, directly addresses the > > root cause, and any new feature that uses dirty bitmaps will then > > automatically get the protection, too. > > > > So in fact, I would say that the bug isn't really fixed (but at best > > papered over) until we add a proper fix on the permission level. > > Okay, we are in agreement about this and you expressed very well why I > (at the gut feeling level) didn't like the old op blockers. But you > bypassed the real question, which is: should I send a pull request for > these two patches or not? :)
I didn't spell it out that explicitly, but this is essentially a NACK. I'd very much prefer if you could replace it with the proper solution. Of course, we can always make exceptions when there is a good reason, but with 2.12 still two months away, I doubt we have one. Kevin
