Re: [Qemu-devel] [PATCH v2] bitmap: Update count after a merge

[Eric Blake]

On 10/3/18 2:57 PM, John Snow wrote:

> > >     - I always forget to update this field.. We definitely should add some
> > > generic check on it somewhere, at least in tests.
> >
> > My suggestion (in another thread) was to enhance
> > x-debug-block-dirty-bitmap-sha256 to include 'count' alongside the
> > checksum, to make it easier to write such tests.
>
> I suppose this is in preference to query-block? It would make it easier.

Well, query-block remains the canonical way for users to access the 
count, while x-debug-block-dirty-bitmap-sha256 is for debugging only 
(basically, for our unit tests, as no one outside of qemu will get much 
use out of it).  But yes, writing a test that uses bitmaps on an 
unconnected BDS is easier than a test that has to use a named device, 
since query-block won't list nodes that aren't connected to a named 
device, and requires a lot more parsing to get at the actual bitmap 
information in comparison to the debug command directly telling you 
about a single bitmap.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org