vmdesc: Allow specifying mkfs arguments

In some cases, the default options selected by the `mkfs.*` utilities
are insufficient. To allow overriding them, volumes and partitions in
the VM description now support an optional `mkfsargs` item, which will
be passed along when creating new filesystems.

src/mkvm/storage.py

@@ -1,6 +1,7 @@
 import logging
 import os
 import pyudev
+import shlex
 import subprocess
 
 
@@ -201,7 +202,7 @@ def get_lv_blockdev(vg_name, lv_name):
     return dev.device_node
 
 
-def mkfs(fstype, device, label=None):
+def mkfs(fstype, device, label=None, mkfsargs=None):
     log.debug(
         'Creating {fstype} filesystem on {device} '
         'with label "{label}"'.format(
@@ -216,6 +217,8 @@ def mkfs(fstype, device, label=None):
         cmd = ['mkfs.{}'.format(fstype), '-q']
     if label:
         cmd += ('-L', label)
+    if mkfsargs:
+        cmd += shlex.split(mkfsargs)
     cmd.append(device)
     try:
         output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)

src/mkvm/vmdesc.py

@@ -172,13 +172,14 @@ class VirtualMachine(object):
         for idx, part in enumerate(self.partitions):
             try:
                 storage.mkfs(part['fstype'], partitions[idx],
-                             part.get('label'))
+                             part.get('label'), part.get('mkfsargs'))
             except KeyError:
                 pass
 
         for vol in self.volumes:
             try:
-                storage.mkfs(vol['fstype'], lv_block(vol['name']), vol['name'])
+                storage.mkfs(vol['fstype'], lv_block(vol['name']), vol['name'],
+                             vol.get('mkfsargs'))
             except KeyError:
                 pass