Re: [Qemu-block] [PATCH 18/22] qapi: add md5 checksum of last dirty bitmap level to query-block

[Max Reitz]

On 10.10.2016 18:44, Max Reitz wrote:
> On 30.09.2016 12:53, Vladimir Sementsov-Ogievskiy wrote:
>> Reviewed-by: John Snow <address@hidden>
>> Reviewed-by: Eric Blake <address@hidden>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>> ---
>>  block/dirty-bitmap.c   | 1 +
>>  include/qemu/hbitmap.h | 8 ++++++++
>>  qapi/block-core.json   | 5 ++++-
>>  util/hbitmap.c         | 8 ++++++++
>>  4 files changed, 21 insertions(+), 1 deletion(-)
> 
> Having read John's and Eric's comments, I won't block this patch, but I
> won't give an R-b either.
> 
> It's probably true that this will not significantly slow down the
> query-block call, but doing this only for debugging does not seem right
> to me.
> 
> I'm not sure what the right way would be to get this information out
> (...maybe make it optional and set it only if qtest_enabled() is true?),
> but in my opinion this is not the right way.

By the way, the cleanest way I can come up with (which I didn't write
about in my first reply because it's not so trivial) would be some kind
of debugging QMP command convention. For instance, we could say that all
debugging commands have an x-debug- prefix, and then you could add an
x-debug-get-bitmap-md5 to read the MD5 hash of a named bitmap. That
would appear to be the cleanest way to do this to me.

Max

> Since I'm not the maintainer of the bitmap code (Fam and John are, even
> though their MAINTAINERS patch is not in master still...), I can't and
> won't block this, though.
> 
> Max
>

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