Am 21.03.2018 um 16:32 hat Alberto Garcia geschrieben: > On Wed 21 Mar 2018 04:07:28 PM CET, Kevin Wolf wrote: > > I just remembered that when I looked at an image recently, I noticed > > that the refcount block wasn't in the first cluster and I disliked it, > > though mostly because it felt untidy rather than being a problem. > > I don't think you can fix that in general. In my test case I'm writing > new data when the existing refcount block is already full, so we can > allocate the new one before the new data and keep everything tidy. > > But if there are, say, two refcount entries available and you write four > data clusters you don't want the new refcount block in the middle of > those four clusters just to have it at the beginning :-)
Agreed. I think if implemented like I suggested (hard error in update_refcount() and then allocate a new refcount block in the caller), we'd actually end up with the refcount block covered by an old refcount block rather than being self-describing. And that in turn wouldn't make things much tidier, so I guess you're right. :-) > > Having a qcow2 analysis script in the repo sounds like a good > > idea. John has something, too. Maybe we can check whether the two > > things complement each other and then check in a script that combines > > both (or if one provides a superset of the other, just check in that > > one). > > I'll take a look. Thanks! Kevin
