Description

I'm loading local images into containerd using ctr images load and trying to reduce disk usage
discard_unpacked_layers=true doesn't work when using ctr, only when using the CRI interface.

Steps to reproduce the issue

1. Start with a containerd without any images
2. Set discard_unpacked_layers = true
3. Run ctr images pull docker.io/library/busybox:latest or ctr images load ...

Describe the results you received and expected

file /var/lib/containerd/io.containerd.content.v1.content/blobs/sha256/* should only show ASCII files
All layers should be deleted

What version of containerd are you using?

containerd github.com/containerd/containerd v1.6.6 10c1295

Any other relevant information

Comment from @dcantah on Slack https://cloud-native.slack.com/archives/C4RJZ9Z6Y/p1656625439107119?thread_ts=1656619851.099629&cid=C4RJZ9Z6Y

Show configuration if it is related to CRI plugin.

No response