From eb0718f442e3196640b101f7277e36165f05855a Mon Sep 17 00:00:00 2001
From: Niels de Vos <ndevos@redhat.com>
Date: Tue, 14 Jun 2022 11:19:57 +0200
Subject: [PATCH] reclaimspace: detect Kubernetes version for right
 StagingTargetPath

Kubernetes 1.24 and newer use a different path for staging the volume.
That means the CSI-driver is requested to mount the volume at an other
location, compared to previous versions of Kubernetes. CSI-drivers
implementing the CSI-Addons NodeReclaimSpace procedure, must receive the
correct path, otherwise the driver will not be able to free space and
possibly return an error.

See-also: kubernetes/kubernetes#107065
See-also: https://bugzilla.redhat.com/2096209
Signed-off-by: Niels de Vos <ndevos@redhat.com>
---
 internal/sidecar/service/reclaimspace.go | 44 +++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/internal/sidecar/service/reclaimspace.go b/internal/sidecar/service/reclaimspace.go
index 6fd3a6fc5..9313a766d 100644
--- a/internal/sidecar/service/reclaimspace.go
+++ b/internal/sidecar/service/reclaimspace.go
@@ -17,7 +17,10 @@ package service
 
 import (
 	"context"
+	"crypto/sha256"
+	"fmt"
 	"path/filepath"
+	"strconv"
 
 	kube "github.com/csi-addons/kubernetes-csi-addons/internal/kubernetes"
 	"github.com/csi-addons/kubernetes-csi-addons/internal/proto"
@@ -140,7 +143,13 @@ func (rs *ReclaimSpaceServer) NodeReclaimSpace(
 		klog.Errorf("Failed to map access mode: %v", err)
 		return nil, status.Error(codes.InvalidArgument, err.Error())
 	}
-	stPath := filepath.Join(rs.stagingPath, "pv", pvName, "globalmount")
+
+	stPath, err := rs.getStagingTargetPath(pv)
+	if err != nil {
+		klog.Errorf("Failed to get staging target path: %v", err)
+		return nil, status.Error(codes.Internal, err.Error())
+	}
+
 	accessType := csi.VolumeCapability_Mount{
 		Mount: &csi.VolumeCapability_MountVolume{},
 	}
@@ -189,3 +198,36 @@ func (rs *ReclaimSpaceServer) NodeReclaimSpace(
 
 	return res, nil
 }
+
+// getStagingTargetPath returns the path where the volume is expected to be
+// mounted (or the block-device is attached/mapped). Different Kubernetes
+// version use different paths.
+func (rs *ReclaimSpaceServer) getStagingTargetPath(pv *corev1.PersistentVolume) (string, error) {
+	// Kubernetes 1.24+ uses a hash of the volume-id in the path name
+	unique := sha256.Sum256([]byte(pv.Spec.CSI.VolumeHandle))
+	targetPath := filepath.Join(rs.stagingPath, pv.Spec.CSI.Driver, fmt.Sprintf("%x", unique), "globalmount")
+
+	version, err := rs.kubeClient.Discovery().ServerVersion()
+	if err != nil {
+		return "", fmt.Errorf("failed to detect Kubernetes version: %w", err)
+	}
+
+	major, err := strconv.Atoi(version.Major)
+	if err != nil {
+		return "", fmt.Errorf("failed to convert Kubernetes major version %q to int: %w", version.Major, err)
+	}
+
+	minor, err := strconv.Atoi(version.Minor)
+	if err != nil {
+		return "", fmt.Errorf("failed to convert Kubernetes minor version %q to int: %w", version.Minor, err)
+	}
+
+	// 'encode' major/minor in a single integer
+	legacyVersion := 1024 // Kubernetes 1.24 => 1 * 1000 + 24
+	if ((major * 1000) + minor) < (legacyVersion) {
+		// path in Kubernetes < 1.24
+		targetPath = filepath.Join(rs.stagingPath, "pv", pv.Name, "globalmount")
+	}
+
+	return targetPath, nil
+}