Merge pull request #263 from aspiers/extra-storage-cache-mode

allow cache mode to be set for additional disks

README.md

@@ -281,6 +281,7 @@ You can create and attach additional disks to a VM via `libvirt.storage :file`.
 * `device` - Name of the device node the disk image will have in the VM, e.g. *vdb*. If unspecified, the next available device is chosen.
 * `size` - Size of the disk image. If unspecified, defaults to 10G.
 * `type` - Type of disk image to create. Defaults to *qcow2*.
+* `cache` - Cache mode to use, e.g. `none`, `writeback`, `writethrough` (see the [libvirt documentation for possible values](http://libvirt.org/formatdomain.html#elementsDisks) or [here](https://www.suse.com/documentation/sles11/book_kvm/data/sect1_chapter_book_kvm.html) for a fuller explanation). Defaults to *default*.
 
 The following example creates two additional disks.
 

lib/vagrant-libvirt/config.rb

@@ -141,6 +141,7 @@ module VagrantPlugins
           :type => options[:type],
           :size => options[:size],
           :path => options[:path],
+          :cache => options[:cache] || 'default',
         }
 
         if storage_type == :file

lib/vagrant-libvirt/templates/domain.xml.erb

@@ -36,7 +36,7 @@
 <%# additional disks -%>
 <% @disks.each do |d| -%>
     <disk type='file' device='disk'>
-      <driver name='qemu' type='<%= d[:type] %>'/>
+      <driver name='qemu' type='<%= d[:type] %>' cache='<%= d[:cache] %>'/>
       <source file='<%= d[:path] %>'/>
       <target dev='<%= d[:device] %>' bus='virtio'/>
 <%# this will get auto generated by libvirt