podman pull writes to read only additional image store

[ankurmalhotra07]

Issue Description

Describe your issue
I have created a read-only directory that will be used as an additional image store ('/var/lib/mycontainers')
However, when I try to pull an image, it throws the following error:
Error: creating lock file directory: mkdir /var/lib/mycontainers/overlay-images: read-only file system
script returned exit code 125

Steps to reproduce the issue

Steps to reproduce the issue
1.mkdir /var/lib/mycontainers
2. podman pull --storage-opt additionalimagestore=/var/lib/mycontainers alpine

Describe the results you received

Error: creating lock file directory: mkdir /var/lib/mycontainers/overlay-images: read-only file system

Describe the results you expected

podman pulls image to primary storage, reusing layers from additional image store. The lock file should only be created in primary storage, not additional image stores which are meant to be read-only

podman info output

Version v4.9

Podman in a container

Yes

Privileged Or Rootless

Privileged

Upstream Latest Release

Yes

Additional environment details

Additional environment details

Additional information

Additional information like issue happens only occasionally or issue happens with a particular architecture or on a particular setting

[ankurmalhotra07]

@giuseppe do you know if the above is a bug? Its a blocker for our use case

[rhatdan]

You need to precreate the lock files in the additional store.

[ankurmalhotra07]

We have a cron job that would populate the additional storage on the node but it might not be ready before client calls podman pull. Can you explain what's the purpose of that lock file?