Use overlay mount type for squashfs diskless images

xCAT-server/share/xcat/netboot/fedora/dracut_009/xcatroot

@@ -52,11 +52,21 @@ if [ -r /rootimg.sfs ]; then
   mkdir -p /rw
   mount -t squashfs /rootimg.sfs /ro
   mount -t tmpfs rw /rw
-  mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
-  mkdir -p $NEWROOT/ro
-  mkdir -p $NEWROOT/rw
-  mount --move /ro $NEWROOT/ro
-  mount --move /rw $NEWROOT/rw
+  modinfo overlay
+  if [ $? -eq 0 ]; then
+      echo "Mounting $NEWROOT with type overlay"
+      mkdir -p /rw/upper
+      mkdir -p /rw/work
+      modprobe overlay
+      mount -t overlay -o lowerdir=/ro,upperdir=/rw/upper,workdir=/rw/work mergedroot $NEWROOT
+  else
+      echo "Mounting $NEWROOT with type aufs"
+      mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
+      mkdir -p $NEWROOT/ro
+      mkdir -p $NEWROOT/rw
+      mount --move /ro $NEWROOT/ro
+      mount --move /rw $NEWROOT/rw
+  fi
 elif [ -r /rootimg.gz ]; then
   echo Setting up RAM-root tmpfs.
   if [ -z $rootlimit ];then

xCAT-server/share/xcat/netboot/rh/dracut/xcatroot

@@ -62,11 +62,21 @@ if [ -r /rootimg.sfs ]; then
   mkdir -p /rw
   mount -t squashfs /rootimg.sfs /ro
   mount -t tmpfs rw /rw
-  mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
-  mkdir -p $NEWROOT/ro
-  mkdir -p $NEWROOT/rw
-  mount --move /ro $NEWROOT/ro
-  mount --move /rw $NEWROOT/rw
+  modinfo overlay
+  if [ $? -eq 0 ]; then
+      echo "Mounting $NEWROOT with type overlay"
+      mkdir -p /rw/upper
+      mkdir -p /rw/work
+      modprobe overlay
+      mount -t overlay -o lowerdir=/ro,upperdir=/rw/upper,workdir=/rw/work mergedroot $NEWROOT
+  else
+      echo "Mounting $NEWROOT with type aufs"
+      mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
+      mkdir -p $NEWROOT/ro
+      mkdir -p $NEWROOT/rw
+      mount --move /ro $NEWROOT/ro
+      mount --move /rw $NEWROOT/rw
+  fi
 elif [ -r /rootimg.cpio.gz ] || [ -r /rootimg.cpio.xz ]; then
   [ "$xcatdebugmode" > "0" ] && logger -t xcat -p debug "rootimg downloaded,setting up RAM-root tmpfs...."
   echo Setting up RAM-root tmpfs.

xCAT-server/share/xcat/netboot/rh/dracut_033/xcatroot

@@ -69,11 +69,21 @@ if [ -r /rootimg.sfs ]; then
     mkdir -p /rw
     mount -t squashfs /rootimg.sfs /ro
     mount -t tmpfs rw /rw
-    mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
-    mkdir -p $NEWROOT/ro
-    mkdir -p $NEWROOT/rw
-    mount --move /ro $NEWROOT/ro
-    mount --move /rw $NEWROOT/rw
+    modinfo overlay
+    if [ $? -eq 0 ]; then
+        echo "Mounting $NEWROOT with type overlay"
+        mkdir -p /rw/upper
+        mkdir -p /rw/work
+        modprobe overlay
+        mount -t overlay -o lowerdir=/ro,upperdir=/rw/upper,workdir=/rw/work mergedroot $NEWROOT
+    else
+        echo "Mounting $NEWROOT with type aufs"
+        mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
+        mkdir -p $NEWROOT/ro
+        mkdir -p $NEWROOT/rw
+        mount --move /ro $NEWROOT/ro
+        mount --move /rw $NEWROOT/rw
+    fi
 elif [ -r /rootimg.cpio.gz ] || [ -r /rootimg.cpio.xz ]; then
     logger $SYSLOGHOST -t $log_label -p local4.info "Setting up RAM-root tmpfs on downloaded rootimg.cpio.[gz/xz]..."
     echo Setting up RAM-root tmpfs.

xCAT-server/share/xcat/netboot/rh/dracut_047/xcatroot

@@ -69,11 +69,21 @@ if [ -r /rootimg.sfs ]; then
     mkdir -p /rw
     mount -t squashfs /rootimg.sfs /ro
     mount -t tmpfs rw /rw
-    mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
-    mkdir -p $NEWROOT/ro
-    mkdir -p $NEWROOT/rw
-    mount --move /ro $NEWROOT/ro
-    mount --move /rw $NEWROOT/rw
+    modinfo overlay
+    if [ $? -eq 0 ]; then
+        echo "Mounting $NEWROOT with type overlay"
+        mkdir -p /rw/upper
+        mkdir -p /rw/work
+        modprobe overlay
+        mount -t overlay -o lowerdir=/ro,upperdir=/rw/upper,workdir=/rw/work mergedroot $NEWROOT
+    else
+        echo "Mounting $NEWROOT with type aufs"
+        mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
+        mkdir -p $NEWROOT/ro
+        mkdir -p $NEWROOT/rw
+        mount --move /ro $NEWROOT/ro
+        mount --move /rw $NEWROOT/rw
+    fi
 elif [ -r /rootimg.cpio.gz ] || [ -r /rootimg.cpio.xz ]; then
     logger $SYSLOGHOST -t $log_label -p local4.info "Setting up RAM-root tmpfs on downloaded rootimg.cpio.[gz/xz]..."
     echo Setting up RAM-root tmpfs.

xCAT-server/share/xcat/netboot/sles/dracut_033/xcatroot

@@ -66,10 +66,20 @@ if [ -r /rootimg.sfs ]; then
   mount -t squashfs /rootimg.sfs /ro
   mount -t tmpfs rw /rw
   mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
-  mkdir -p $NEWROOT/ro
-  mkdir -p $NEWROOT/rw
-  mount --move /ro $NEWROOT/ro
-  mount --move /rw $NEWROOT/rw
+  modinfo overlay
+  if [ $? -eq 0 ]; then
+      echo "Mounting $NEWROOT with type overlay"
+      mkdir -p /rw/upper
+      mkdir -p /rw/work
+      modprobe overlay
+      mount -t overlay -o lowerdir=/ro,upperdir=/rw/upper,workdir=/rw/work mergedroot $NEWROOT
+  else
+      echo "Mounting $NEWROOT with type aufs"
+      mkdir -p $NEWROOT/ro
+      mkdir -p $NEWROOT/rw
+      mount --move /ro $NEWROOT/ro
+      mount --move /rw $NEWROOT/rw
+  fi
 elif [ -r /rootimg.cpio.gz ] || [ -r /rootimg.cpio.xz ]; then
   logger $SYSLOGHOST -t $log_label -p local4.info "Setting up RAM-root tmpfs on downloaded rootimg.cpio.[gz/xz]..."
   echo Setting up RAM-root tmpfs.

xCAT-server/share/xcat/netboot/ubuntu/dracut/xcatroot

@@ -34,11 +34,21 @@ if [ -r /rootimg.sfs ]; then
   mkdir -p /rw
   mount -t squashfs /rootimg.sfs /ro
   mount -t tmpfs rw /rw
-  mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
-  mkdir -p $NEWROOT/ro
-  mkdir -p $NEWROOT/rw
-  mount --move /ro $NEWROOT/ro
-  mount --move /rw $NEWROOT/rw
+  modinfo overlay
+  if [ $? -eq 0 ]; then
+      echo "Mounting $NEWROOT with type overlay"
+      mkdir -p /rw/upper
+      mkdir -p /rw/work
+      modprobe overlay
+      mount -t overlay -o lowerdir=/ro,upperdir=/rw/upper,workdir=/rw/work mergedroot $NEWROOT
+  else
+      echo "Mounting $NEWROOT with type aufs"
+      mount -t aufs -o dirs=/rw:/ro mergedroot $NEWROOT
+      mkdir -p $NEWROOT/ro
+      mkdir -p $NEWROOT/rw
+      mount --move /ro $NEWROOT/ro
+      mount --move /rw $NEWROOT/rw
+  fi
 elif [ -r /rootimg.cpio.gz ] || [ -r /rootimg.cpio.xz ]; then
   echo Setting up RAM-root tmpfs.
   mount -t tmpfs -o mode=755 rootfs $NEWROOT