Check for presence of btrfs before trying to use it

If btrfs is not present in the kernel we end up with strange output like
this:

    Error creating disk image2014-06-10 16:00:40
    [devel-system-x86_64-generic][my-raw-disk-image][rawdisk.write]Failure
    to create disk image at /src/tmp/testdev.img
    ERROR: Command failed: mount -o loop /src/tmp/testdev.img
    /src/tmp/deployments/tmpQ7wXO1/tmp4lVDcu/tmpvHSzDE
    mount: mounting /dev/loop0 on
    /src/tmp/deployments/tmpQ7wXO1/tmp4lVDcu/tmpvHSzDE failed: Device or
    resource busy

To avoid this confusing error, Morph should explicitly check first.

4 files changed, 37 insertions, 0 deletions

diff --git a/kvm.check b/kvm.check
index 957d0893..1bb4007a 100755
--- a/kvm.check
+++ b/kvm.check
@@ -31,6 +31,8 @@ class KvmPlusSshCheckExtension(morphlib.writeexts.WriteExtension):
         if len(args) != 1:
             raise cliapp.AppException('Wrong number of command line args')
 
+        self.require_btrfs_in_deployment_host_kernel()
+
         upgrade = self.get_environment_boolean('UPGRADE')
         if upgrade:
             raise cliapp.AppException(
diff --git a/openstack.check b/openstack.check
index a9a8fe1b..b5173011 100755
--- a/openstack.check
+++ b/openstack.check
@@ -26,6 +26,8 @@ class OpenStackCheckExtension(morphlib.writeexts.WriteExtension):
         if len(args) != 1:
             raise cliapp.AppException('Wrong number of command line args')
 
+        self.require_btrfs_in_deployment_host_kernel()
+
         upgrade = self.get_environment_boolean('UPGRADE')
         if upgrade:
             raise cliapp.AppException(
diff --git a/rawdisk.check b/rawdisk.check
new file mode 100755
index 00000000..6a656ee7
--- /dev/null
+++ b/rawdisk.check
@@ -0,0 +1,31 @@
+#!/usr/bin/python
+# Copyright (C) 2014  Codethink Limited
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+'''Preparatory checks for Morph 'rawdisk' write extension'''
+
+import cliapp
+
+import morphlib.writeexts
+
+
+class RawdiskCheckExtension(morphlib.writeexts.WriteExtension):
+    def process_args(self, args):
+        if len(args) != 1:
+            raise cliapp.AppException('Wrong number of command line args')
+
+        self.require_btrfs_in_deployment_host_kernel()
+
+RawdiskCheckExtension().run()
diff --git a/virtualbox-ssh.check b/virtualbox-ssh.check
index 1aeb8999..57d54db1 100755
--- a/virtualbox-ssh.check
+++ b/virtualbox-ssh.check
@@ -26,6 +26,8 @@ class VirtualBoxPlusSshCheckExtension(morphlib.writeexts.WriteExtension):
         if len(args) != 1:
             raise cliapp.AppException('Wrong number of command line args')
 
+        self.require_btrfs_in_deployment_host_kernel()
+
         upgrade = self.get_environment_boolean('UPGRADE')
         if upgrade:
             raise cliapp.AppException(