Description of problem:
Reading data from persistent storage provided by csi will report "Permission denied" error

Version-Release number of selected component (if applicable):
oc v3.10.0-0.38.0
openshift v3.10.0-0.41.0
kubernetes v1.10.0+b81c8f8
csi-attacher-0.2.0-2.git27299be.el7.x86_64
csi-provisioner-0.2.0-1.el7.x86_64
csi-driver-registrar-0.2.0-1.el7.x86_64

How reproducible:
Deploy csi per https://github.com/openshift/openshift-docs/pull/8783/files

Steps to Reproduce:
1. Create PVC
# cat pvc.yaml 
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc1 
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

2. Create Pod
# cat pod.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: web-server
spec:
  containers:
   - name: web-server
     image: nginx 
     volumeMounts:
       - mountPath: /var/lib/www/html
         name: mypvc
  volumes:
   - name: mypvc
     persistentVolumeClaim:
       claimName: pvc1
       readOnly: false

3. Read data from persistent storage provided by csi

Actual results:
# oc exec web-server -- ls /var/lib/www/html
ls: cannot open directory '/var/lib/www/html': Permission denied

Expected results:
Could read and write data successfully.

Master Log:

Node Log (of failed PODs):

PV Dump:

PVC Dump:

StorageClass Dump (if StorageClass used by PV/PVC):

Additional info: