create temporary snapshot on the parent image same as
name as the temporary clone rbd image. Naming the snapshot
and the temporary cloned image helps to flatten the temporary
cloned images when the snapshots on the parent image exceeds
the configured maxSnapshotsOnImage.
Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
Added support for RBD PVC to PVC cloning, below
commands are executed to create a PVC-PVC clone from
RBD side.
* Check the depth(n) of the cloned image if n>=(hard limit -2)
or ((soft limit-2) Add a task to flatten the image and return
about (to avoid image leak) **Note** will try to flatten the
temp clone image in the chain if available
* Reserve the key and values in omap (this will help us to
avoid the leak as it's not reserved earlier as we have returned
ABORT (the request may not come back))
* Create a snapshot of rbd image
* Clone the snapshot (temp clone)
* Delete the snapshot
* Snapshot the temp clone
* Clone the snapshot (final clone)
* Delete the snapshot
```bash
1) check the image depth of the parent image if flatten required
add a task to flatten image and return ABORT to avoid leak
(hardlimit-2 and softlimit-2 check will be done)
2) Reserve omap keys
2) rbd snap create <RBD image for src k8s volume>@<random snap name>
3) rbd clone --rbd-default-clone-format 2 --image-feature
layering,deep-flatten <RBD image for src k8s volume>@<random snap>
<RBD image for temporary snap image>
4) rbd snap rm <RBD image for src k8s volume>@<random snap name>
5) rbd snap create <cloned RBD image created in snapshot process>@<random snap name>
6) rbd clone --rbd-default-clone-format 2 --image-feature <k8s dst vol config>
<RBD image for temporary snap image>@<random snap name> <RBD image for k8s dst vol>
7)rbd snap rm <RBD image for src k8s volume>@<random snap name>
```
* Delete temporary clone image created as part of clone(delete if present)
* Delete rbd image
Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
