tl;dr: I tried to cancel a long operation, but KDEPM is waiting for it to finish, and presumably will undo it afterwards.

Can I cancel the cancellation, so that it won't be undone at the end?

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More context below:

The operation is growing a large NTFS partition, to the "left". It's meant to take 9 hours, about 7 remaining now.
(I understand why it's taking so long, I don't need an explanation)
I tried to cancel it so I could do it at a better time, but since apparently it can't be cancelled midway, I'd rather it finishes as soon as it can. But since I told KDEPM to cancel the operation, I'm afraid it's going to immediately start reversing it. What can I do to prevent that reversing?
I doubt I can just kill KDEPM, it would probably leave the data in an undreadable state.