rbd: add ListChildrenAttributes Api

[ShravaniVangur]

The existing ListChildren() API provides only basic information, specifically the pool and image names of a given image’s children. However, in many scenarios, additional metadata is required to fully understand the relationships between images.

This new API extends functionality by leveraging rbd_list_children3(rbd_image_t image, rbd_linked_image_spec_t *images, size_t *max_images), which enables the retrieval of comprehensive details, including:

• Image and pool IDs
• Image and pool names
• Pool namespace
• The trash status of child images

By exposing this additional metadata, the API allows for more informed decision-making when managing child images. Furthermore, modifying the existing ListChildren() API would introduce backward compatibility issues, potentially breaking existing implementations. To avoid such disruptions while still providing enhanced capabilities, this new API has been introduced as a separate function.

Checklist

• Added tests for features and functional changes
• Public functions and types are documented
• Standard formatting is applied to Go code
• Is this a new API? Added a new file that begins with //go:build ceph_preview
• Ran make api-update to record new APIs

New or infrequent contributors may want to review the go-ceph Developer's Guide including the section on how we track API Status and the API Stability Plan.

The go-ceph project uses mergify. View the mergify command guide for information on how to interact with mergify. Add a comment with @Mergifyio rebase to rebase your PR when github indicates that the PR is out of date with the base branch.

[Rakshith-R]

Tiny nit regarding function definition, everything else looks good to me.

corresponding cephcsi issue to include this new API: ceph/ceph-csi#5173

/cc @nixpanic @phlogistonjohn @anoopcs9 @ansiwen

[phlogistonjohn]

Overall, this looks like a very good start. Most of my suggestions are related to the naming conventions we currently use.

[phlogistonjohn]

Code looks good to me now.
However, you need to update the commit message to match the new name. Also since I'm asking you to change the commit messge title: it should be 'add' not 'adding' to give the commit title an imperative tone

[phlogistonjohn]

LGTM, thanks for this, it was a really nice PR!

[ShravaniVangur]

@anoopcs9 @phlogistonjohn
Would the API Label be required on this PR?

[anoopcs9]

@anoopcs9 @phlogistonjohn Would the API Label be required on this PR?

Initially I was wondering why there wasn't any ceph_preview build tag added to the source files which led me to the realization that the underlying librbd API was not new. Anyway "API" label is needed for automatic merge once required number of approvals are present.

[phlogistonjohn]

Yeah, I forgot the label. As a reminder: the API vs. non-API label stuff is advisory not a hard rule. Some stuff is obvious like a Makefile fix would be non-API, this is API but like you note it's not adding something net new and the underlying ceph API is supported by all ceph versions that we test.

As I already approved it is probably clear I didn't think the preview api status was necessary. It reuses an existing type and an existing api. If I had a time machine it would have been the correct way to implment ListChildren in the first place. But we can discuss it more if you feel strongly about it.

Pull request has been modified.

[Rakshith-R]

Thanks, LGTM

[anoopcs9]

@Mergifyio rebase

[mergify]

rebase

✅ Branch has been successfully rebased

[anoopcs9]

lgtm, thanks.