fix: override same chunk

[acha-bill]

Checklist

• I have read the coding guide.
• My change requires a documentation update, and I have done it.
• I have added tests to cover my changes.
• I have filled out the description and linked the related issues.

Description

Override chunk with the same address.

When we attempt to delete the chunk, the delete operation is appended to the current batch. However, since this Get reads from disk, it returns the old refCnt. So it ignores the new chunk.

To fix this, we introduce a new replace method that does not relly on refCnt.

Related Issue (Optional)

#4739

[ldeffenb]

I like the look of this better, simply replace it within the transaction rather than the possibility of dangling/orphan chunks.

[ldeffenb]

See if I can remember to add this metric to one of my Grafana dashboards!

[nugaon]

While it resolves #4739 , I hoped we can handle two problems at the same time.

This fix does not cover the case when one uses postage stamp for the replaced single owner chunk; that stamp is used up for a non-living chunk on the uploader side when storage providers do not benefit from this pull syncing.
Former is not that significant problem especially if the batch is mutable while the last could be a huge improvement IMO since this is a supported feature in storage incentives with which operators can grow they reserve.

Nevertheless, there is no chunk retrieval mechanism to download different payloads of SOC at the moment, (also may require sharky changes) so we should merge this in order to have a more solid shelling point.

[istae]

much better, let's also add some comments though

[nugaon]

hmm, I was not aware of these kind of different stores used for storing chunk, but I have some questions/comments regarding that below.

[istae]

nice!
one final change request https://github.com/ethersphere/bee/pull/4749/files#diff-e37eed2ab5dfe1533be0257473f5b76738361f02d2be71da1b7bf4d5216a00c7R294: the size change here now also has to consider the same chunk address check.

should be:

if !loadedStamp && sameAddressOldChunkStamp == nil {
   r.size.Add(1)
}