Re: [Qemu-block] [PATCH v3 3/5] qcow2: Introduce an option for sufficient L2 cache for the entire image

[Leonid Bloch]

> > You mean with QDict? I'll look into that now. But already sent v5 before
> > reading this email.
>
> Yes, with reading it from the QDict. (Or whatever the simplest way is
> that results in the right external interface, but I suppose this is the
> one.)

Well, there is a problem with that: I can easily isolate
l2-cache-size from QDict, check if it is "full", and if it is - do 
whatever is needed, and delete this option before parsing. But what if 
it is "foo"? It will not get deleted, and the regular QEMU_OPT_SIZE 
parsing error will appear, stating that l2-cache-size "expects a 
non-negative number..." - no word about that it can expect "full" as 
well. Now, one can try to modify local_err->msg for this particular 
option, but this will require substantial additional logic. I think 
considering this, it would be easier to stick with a dedicated option, 
l2-cache-full.

Do you think there is a smarter way to parse the l2-cache-size option, 
so it would accept both size and "full", while handling errors 
correctly? It seems more elegant to have a single option, but the 
internal handling will be more elegant and simpler with two mutually 
exclusive options.

By the way, the L2 cache resizes now on image resize. Will send the 
changes in v6. Thanks for the suggestion!

Leonid.