[CephFS] Support volume cloning

[ajarr]

Describe the feature you'd like to have

CSI volume cloning is beta in k8s v1.16
https://kubernetes.io/docs/concepts/storage/volume-pvc-datasource/
https://kubernetes.io/blog/2019/06/21/introducing-volume-cloning-alpha-for-kubernetes/

CephFS CSI driver should be able to support volume cloning similar to the RBD CSI driver.

[humblec]

@joscollin Can you please update where we are with this feature ? we are planning to have this in 2.1.0 .

[humblec]

/assign @joscollin

[joscollin]

@humblec
The Versioned Subvolume Provisioning and Clone From Snapshot are under review and the Versioned Subvolume Provisioning will get merged soon. We need to implement Restore From Snap too and will be done post clone.

We expect this work would be completed and could be consumed by the end of January.

[humblec]

Thanks for the update @joscollin 👍
Considering the timeline planned this is a good fit for release 2.1.0

[joscollin]

@ajarr @humblec Isn't this a duplicate of #411? If duplicate, please close this ticket.

[Madhu-1]

@joscollin this is not duplicate, This is cloning a PVC from PVC not really about cloning/creating a subvolume from a snapshot

[humblec]

@joscollin can you update whats the current state of this functionality support ? to make it clear, are we able to clone a volume from another volume ?

[joscollin]

No, it is not possible now.

[humblec]

CephFS Tracker : https://tracker.ceph.com/issues/45290

[Madhu-1]

Moving it to release-v3.1.0

[humblec]

This can be closed now as #394 is merged and provide the functionality. 👍