Merge pull request #61011 from mlmhl/csi_readonly

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Set readOnly for CSI mounter

**What this PR does / why we need it**:

Currently the `csiMountMgr .readOnly` field is never set, we should set it to `Spec.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 #61008 

**Special notes for your reviewer**:

Currently, most of the volume plugins use a `getVolumeSourceFromSpec` method to fetch `VolumeSource` and `ReadOnly` from `volume.Spec`. If the volume is an inline volume, `ReadOnly` is fetched from `Spec.Volume.<SpecificVolumeSource>.ReadOnly`, and if the volume is a `PersistentVolume`, `ReadOnly` is set to `Spec.Readonly`, which comes from `PersistentVolumeClaimVolumeSource.ReadOnly`.

However, as CSI volume plugin is only supported in `PersistentVolume`, so we can just set `ReadOnly` to `Spec.ReadOnly`.

**Release note**:

```release-note
NONE
```

/sig storage

pkg/volume/csi/csi_plugin.go

@@ -98,6 +98,10 @@ func (p *csiPlugin) NewMounter(
 	if err != nil {
 		return nil, err
 	}
+	readOnly, err := getReadOnlyFromSpec(spec)
+	if err != nil {
+		return nil, err
+	}
 
 	// before it is used in any paths such as socket etc
 	addr := fmt.Sprintf(csiAddrTemplate, pvSource.Driver)
@@ -120,6 +124,7 @@ func (p *csiPlugin) NewMounter(
 		volumeID:     pvSource.VolumeHandle,
 		specVolumeID: spec.Name(),
 		csiClient:    client,
+		readOnly:     readOnly,
 	}
 	return mounter, nil
 }
@@ -217,6 +222,15 @@ func getCSISourceFromSpec(spec *volume.Spec) (*api.CSIPersistentVolumeSource, er
 	return nil, fmt.Errorf("CSIPersistentVolumeSource not defined in spec")
 }
 
+func getReadOnlyFromSpec(spec *volume.Spec) (bool, error) {
+	if spec.PersistentVolume != nil &&
+		spec.PersistentVolume.Spec.CSI != nil {
+		return spec.ReadOnly, nil
+	}
+
+	return false, fmt.Errorf("CSIPersistentVolumeSource not defined in spec")
+}
+
 // log prepends log string with `kubernetes.io/csi`
 func log(msg string, parts ...interface{}) string {
 	return fmt.Sprintf(fmt.Sprintf("%s: %s", csiPluginName, msg), parts...)