In the 'basic' case we have few bitmaps in only the top layer. Simulate
commit into the backing of the top layer and also 2 levels deep.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Reuse qemuBlockGetBitmapMergeActions which allows removing the ad-hoc
implementation of bitmap merging for block commit. The new approach is
way simpler and more robust and also allows us to get rid of the
disabling of bitmaps done prior to the start as we actually do want to
update the bitmaps in the base.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Add code for testing the two necessary steps of handling bitmaps during
block commit and exercise the code on the test data which we have for
bitmap handling.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>