Description of problem (please be detailed as possible and provide log
snippests):

When creating a block-mode volume (RBD backend), it is not possible to store the requested amount of data on the block device.

Version of all relevant components (if applicable):

all

Does this issue impact your ability to continue to work with the product
(please explain in detail what is the user impact)?

Yes. KubeVirt/CDI creates a PVC for a virtual-machine disk, and extracts a disk-image on the PVC. If that PVC is smaller than requested, extracting the disk-image fails and the virtual-machine can not be created.

Is there any workaround available to the best of your knowledge?

Create larger PVCs than needed, but it is unclear how much extra space needs to be requested for the encryption overhead.

Rate from 1 - 5 the complexity of the scenario you performed that caused this
bug (1 - very simple, 5 - very complex)?

1 - very simple

Can this issue reproducible?

Yes.

Can this issue reproduce from the UI?

Yes, although it involves quite a few steps.

If this is a regression, please provide more details to justify this:

Not a regression, a bug from initial feature development.

Steps to Reproduce:
1. create a 20Gib block-mode PVC
2. try to write 20Gib to the block-device in a Pod

Actual results:

Writing 20Gib fails.

Expected results:

Writing 20Gib should succeed.

Additional info:

This problem occurs with filesystem-mode PVCs as well. However, it is well understood that filesystem-metadata takes some space. When requesting a (raw) block-mode PVC, it is not expected that there is some space reserved (in this case for encryption).