Re: [patch] Fix checksum verification in base backups for zero page headers

On Fri, Oct 23, 2020 at 08:00:08AM +0900, Michael Paquier wrote:
> Yeah, we could try to make the logic a bit more complicated like
> that.  However, for any code path relying on a page read without any
> locking insurance, we cannot really have a lot of trust in any of the
> fields assigned to the page as this could just be random corruption
> garbage, and the only thing I am ready to trust here a checksum
> mismatch check, because that's the only field on the page that's
> linked to its full contents on the 8k page.  This also keeps the code
> simpler.

A small update here.  I have extracted the refactored part for
PageIsVerified() and committed it as that's independently useful.
This makes the patch proposed here simpler on HEAD, leading to the
attached.
--
Michael