Re: [RFC qemu 0/6] mirror: implement incremental and bitmap modes

[John Snow]

On 8/21/20 9:03 AM, Max Reitz wrote:
> On 18.02.20 11:07, Fabian Grünbichler wrote:
>
> [Sorry :/]
>
> > picking up on John's in-progress patch series from last summer, this is
> > a stab at rebasing and adding test cases for the low-hanging fruits:
> >
> > - bitmap mirror mode with always/on-success/never bitmap sync mode
> > - incremental mirror mode as sugar for bitmap + on-success
> >
> > Fabian Grünbichler (4):
> >    mirror: add check for bitmap-mode without bitmap
> >    mirror: switch to bdrv_dirty_bitmap_merge_internal
> >    iotests: add test for bitmap mirror
> >    mirror: move some checks to QMP
> >
> > John Snow (2):
> >    drive-mirror: add support for sync=bitmap mode=never
> >    drive-mirror: add support for conditional and always bitmap sync modes
>
> Looks reasonable to me.  I would indeed merge patches 2 through 4 into a
> single one, and perhaps switch patches 5 and 6.
>
> Also, we still need an S-o-b from John on patch 2.

Whoops! Will do.

> I have one question: When the mirror job completes successfully (or is
> cancelled “successfully”), the bitmap is always fully cleared when the
> job completes, right?  (Unless in “never” mode.)

I don't remember personally, it's been a minute ...

> Not that I think we should change the current implementation of “clear
> sync_bitmap; merge dirty_bitmap into sync_bitmap;”.  Just a question for
> understanding.
>
>
> Soo...  What’s the plan?
>
> Max