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passthrough readOnly to subpath
**What this PR does / why we need it**:
If a volume is mounted as readonly, or subpath volumeMount is configured as readonly, then the subpath bind mount should be readonly.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes#62752
**Special notes for your reviewer**:
**Release note**:
```release-note
Fixes issue where subpath readOnly mounts failed
```
Users must not be allowed to step outside the volume with subPath.
Therefore the final subPath directory must be "locked" somehow
and checked if it's inside volume.
On Windows, we lock the directories. On Linux, we bind-mount the final
subPath into /var/lib/kubelet/pods/<uid>/volume-subpaths/<container name>/<subPathName>,
it can't be changed to symlink user once it's bind-mounted.
Jan Safranek