[PATCH 10/32] qemublocktest: Disable testcases for all bitmap handling

Eric Blake eblake at redhat.com
Wed Jun 17 20:58:07 UTC 2020

On 6/15/20 12:09 PM, Peter Krempa wrote:
> Upcoming patches are going to rewrite and semantically modify how
> bitmaps are handled during blockjobs. This is possible as incremental
> backup is not yet fully enabled.
> As the changes are going to be incompatible with any current test data
> remove all test cases for bitmap handling during checkpoint deletion,
> incremental backups, block commit, block copy, and bitmap validation
> operations.
> The tests will be gradually added back later after the code and
> test-data is refactored.
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---

>   49 files changed, 2909 deletions(-)

And this is the point where we have to commit on which interface we will 
stick to once we allow incremental backups by default rather than just 
by opting in.  With your idea of keeping multiple bitmaps active, we may 
need to tweak qemu to be more efficient at how it stores bitmap 
information (for example, instead of having each guest write modify the 
in-memory representation of all active bitmaps, which only get flushed 
to disk when closing the guest, we could instead have qemu store guest 
writes into a single in-memory bitmap, then merge that into all active 
bitmaps when flushing) - but that's for qemu to worry about.  In the 
meantime, if your n ew proposed bitmap handling is easier to manage in 
libvirt, even if it costs more work in current qemu, I think we can live 
with that.

I'm reluctant to ack this patch until I've seen the rest of the series 
adding support back in, but unless something major turns up in the rest 
of the series, the approach of a clean slate followed by a new 
implementation is reasonable enough.

Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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