Re: [Qemu-devel] [PATCH for-4.1] util/hbitmap: update orig_size on truncate

[Paolo Bonzini]

On 05/08/19 14:19, Max Reitz wrote:
> On 05.08.19 14:01, Vladimir Sementsov-Ogievskiy wrote:
>> Without this, hbitmap_next_zero and hbitmap_next_dirty_area are broken
>> after truncate. So, orig_size is broken since it's introduction in
>> 76d570dc495c56bb.
>>
>> Fixes: 76d570dc495c56bb
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>> ---
>>
>> Hi!
>>
>> Here is one more hbitmap bug I noticed. It's my fault, I'm sorry :(
>> Broken in 4.0, but if we are already going to fix in 4.1 some things
>> around it, it's a small meaningful addition.
> 
> Hm. :-/
> 
>> Users of broken API are incremental backup, sync mirror (but it may not
>> be broken, if truncates not allowed during mirror, are they?),
> 
> It doesn’t appear that way (we don’t share BLK_PERM_RESIZE).
> 
>> bitmap export through NBD.
> 
> I suppose that counts as block-y enough for me to take it.  Well, I’d
> still like a test case to see the impact...  I’ll see whether I can come
> up with something.

And also a unit test...

Paolo