virt: add more properties to generate volume XML

In order to generate almost all the volumes that libvirt can handle, add
the type, backingStore, permissions and allocation parameters to the
virt._gen_vol_xml() function.

Also make the format parameter optional since libvirt has default values
depending on the storage backend.

salt/modules/virt.py

@@ -665,15 +665,28 @@ def _gen_xml(
     return template.render(**context)
 
 
-def _gen_vol_xml(name, format, size):
+def _gen_vol_xml(
+    name,
+    size,
+    format=None,
+    allocation=0,
+    type=None,
+    permissions=None,
+    backing_store=None,
+    nocow=False,
+):
     """
     Generate the XML string to define a libvirt storage volume
     """
     size = int(size) * 1024  # MB
     context = {
+        "type": type,
         "name": name,
+        "target": {"permissions": permissions, "nocow": nocow},
         "format": format,
         "size": six.text_type(size),
+        "allocation": six.text_type(int(allocation) * 1024),
+        "backingStore": backing_store,
     }
     fn_ = "libvirt_volume.jinja"
     try:
@@ -1561,7 +1574,7 @@ def init(
                 log.debug("Generating libvirt XML for %s", _disk)
                 volume_name = "{0}/{1}".format(name, _disk["name"])
                 filename = "{0}.{1}".format(volume_name, _disk["format"])
-                vol_xml = _gen_vol_xml(filename, _disk["format"], _disk["size"])
+                vol_xml = _gen_vol_xml(filename, _disk["size"], format=_disk["format"])
                 define_vol_xml_str(vol_xml, pool=_disk.get("pool"))
 
         elif virt_hypervisor in ["qemu", "kvm", "xen"]:

salt/templates/virt/libvirt_volume.jinja

@@ -1,10 +1,39 @@
-<volume>
+<volume{% if type %} type='{{ type }}'{% endif %}>
   <name>{{ name }}</name>
   <source>
   </source>
   <capacity unit='KiB'>{{ size }}</capacity>
-  <allocation unit='KiB'>0</allocation>
+  <allocation unit='KiB'>{{ allocation }}</allocation>
   <target>
+    {%- if format %}
     <format type='{{ format }}'/>
+    {%- endif %}
+    {%- if target.permissions -%}
+    <permissions>
+      {%- if target.permissions.get('mode') %}
+      <mode>{{ target.permissions.mode }}</mode>
+      {%- endif %}
+      {%- if target.permissions.get('owner') %}
+      <owner>{{ target.permissions.owner }}</owner>
+      {%- endif %}
+      {%- if target.permissions.get('group') %}
+      <group>{{ target.permissions.group }}</group>
+      {%- endif %}
+      {%- if target.permissions.get('label') %}
+      <label>{{ target.permissions.label }}</label>
+      {%- endif %}
+    </permissions>
+    {%- endif %}
+    {%- if target.nocow %}
+    <nocow/>
+    {%- endif %}
   </target>
+  {%- if backingStore %}
+  <backingStore>
+    <path>{{ backingStore.path }}</path>
+    {%- if backingStore.format %}
+    <format type='{{ backingStore.format }}'/>
+    {%- endif %}
+  </backingStore>
+  {%- endif %}
 </volume>

tests/unit/modules/test_virt.py

@@ -538,13 +538,54 @@ class VirtTestCase(TestCase, LoaderModuleMockMixin):
         """
         Test virt._get_vol_xml() for the ESX case
         """
-        xml_data = virt._gen_vol_xml("vmname/system.vmdk", "vmdk", 8192)
+        xml_data = virt._gen_vol_xml("vmname/system.vmdk", 8192, format="vmdk")
         root = ET.fromstring(xml_data)
         self.assertIsNone(root.get("type"))
         self.assertEqual(root.find("name").text, "vmname/system.vmdk")
         self.assertEqual(root.find("capacity").attrib["unit"], "KiB")
         self.assertEqual(root.find("capacity").text, six.text_type(8192 * 1024))
+        self.assertEqual(root.find("allocation").text, six.text_type(0))
         self.assertEqual(root.find("target/format").get("type"), "vmdk")
+        self.assertIsNone(root.find("target/permissions"))
+        self.assertIsNone(root.find("target/nocow"))
+        self.assertIsNone(root.find("backingStore"))
+
+    def test_gen_vol_xml_file(self):
+        """
+        Test virt._get_vol_xml() for a file volume
+        """
+        xml_data = virt._gen_vol_xml(
+            "myvm_system.qcow2",
+            8192,
+            format="qcow2",
+            allocation=4096,
+            type="file",
+            permissions={
+                "mode": "0775",
+                "owner": "123",
+                "group": "456",
+                "label": "sec_label",
+            },
+            backing_store={"path": "/backing/image", "format": "raw"},
+            nocow=True,
+        )
+        root = ET.fromstring(xml_data)
+        self.assertEqual(root.get("type"), "file")
+        self.assertEqual(root.find("name").text, "myvm_system.qcow2")
+        self.assertIsNone(root.find("key"))
+        self.assertIsNone(root.find("target/path"))
+        self.assertEqual(root.find("target/format").get("type"), "qcow2")
+        self.assertEqual(root.find("capacity").attrib["unit"], "KiB")
+        self.assertEqual(root.find("capacity").text, six.text_type(8192 * 1024))
+        self.assertEqual(root.find("capacity").attrib["unit"], "KiB")
+        self.assertEqual(root.find("allocation").text, six.text_type(4096 * 1024))
+        self.assertEqual(root.find("target/permissions/mode").text, "0775")
+        self.assertEqual(root.find("target/permissions/owner").text, "123")
+        self.assertEqual(root.find("target/permissions/group").text, "456")
+        self.assertEqual(root.find("target/permissions/label").text, "sec_label")
+        self.assertIsNotNone(root.find("target/nocow"))
+        self.assertEqual(root.find("backingStore/path").text, "/backing/image")
+        self.assertEqual(root.find("backingStore/format").get("type"), "raw")
 
     def test_gen_xml_for_kvm_default_profile(self):
         """