[PATCH 3/5] qemu: block: Remove 'active-write' bitmap even if there are no bitmaps to merge

[Eric Blake]

On 7/16/20 9:20 AM, Peter Krempa wrote:
> The 'libvirt-tmp-activewrite' bitmap is added during the 'pivot'
> operation of block copy and active layer block commit operations
> regardless of whether there are any bitmaps to merge, but was not
> removed unless a bitmap was merged. This meant that subsequent attempts
> to merge into the same image would fail.
> 
> Fix it by checking whether the 'libvirt-tmp-activewrite' would be used
> by the code and don't skip the code which would delete it.
> 
> This is a regression introduced when we switched to the new code for
> block commit in <20a7abc2d2d> and for block copy in <7bfff40fdfe5>. The
> actual bug originates from <4fa8654ece>.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1857735
> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---

Reviewed-by: Eric Blake <eblake at redhat.com>

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