On 03/12/2012 01:04 PM, Kevin Wolf wrote: > >> > >> qcow2 can't handle clusters that are referenced twice from the same L1 > >> table. This would require a reverse lookup to adjust the QCOW_O_COPIED > >> flags in the L2 tables containing the other references. > > > > Don't follow, sorry. What adjustment are you talking about? > > > > If it's a 1->0 transition, is it mandatory to adjust the flag? That is, > > it it legal to have a refcount of exactly one, but have the flag clear? > > According to the spec it's illegal and qemu-img check will complain, > too. In practice, I'm not entirely sure if it will cause real corruption > or just unnecessary COWs. I believe it may be the latter.
We could retro-doc it but I'm not a huge fan of this practice. > But it's not worth the trouble anyway when we can have a real zero flag > in qcow3. ok. Thanks for the explanations. -- error compiling committee.c: too many arguments to function
