protokube: check for device symlinks

protokube/pkg/protokube/kube_boot.go

@@ -19,6 +19,7 @@ package protokube
 import (
 	"fmt"
 	"net"
+	"path/filepath"
 	"time"
 
 	"github.com/golang/glog"
@@ -195,6 +196,17 @@ func pathFor(hostPath string) string {
 	return RootFS + hostPath[1:]
 }
 
+func pathForSymlinks(hostPath string) string {
+	path := pathFor(hostPath)
+
+	symlink, err := filepath.EvalSymlinks(path)
+	if err != nil {
+		return path
+	}
+
+	return symlink
+}
+
 func (k *KubeBoot) String() string {
 	return DebugString(k)
 }

protokube/pkg/protokube/volume_mounter.go

@@ -187,8 +187,8 @@ func (k *VolumeMountController) safeFormatAndMount(volume *Volume, mountpoint st
 		}
 
 		if mountedDevice != "" {
-			// We check that it is the correct device.  We also tolerate /dev/X as well as /root/dev/X
+			// We check that it is the correct device.  We also tolerate /dev/X as well as /root/dev/X and any of symlinks to them
-			if mountedDevice != source && mountedDevice != device {
+			if mountedDevice != source && mountedDevice != device && pathFor(mountedDevice) != pathForSymlinks(device) {
 				return fmt.Errorf("device already mounted at %s, but is %s and we want %s or %s", target, mountedDevice, source, device)
 			}
 		} else {