From 89922b60f2e94b6ca341a432f295a581a92f045f Mon Sep 17 00:00:00 2001
From: Paul Bourke <paul.bourke@oracle.com>
Date: Wed, 14 Jun 2017 13:04:23 +0100
Subject: [PATCH] Update loopback instructions in cinder docs

losetup/fallocate are better and match what we have for Swift.

Change-Id: I1147374017e4f1cb3f3e970e048ba565388cd86f
---
 doc/cinder-guide.rst | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/doc/cinder-guide.rst b/doc/cinder-guide.rst
index a6ba19f3ab..5975b1e566 100644
--- a/doc/cinder-guide.rst
+++ b/doc/cinder-guide.rst
@@ -45,11 +45,12 @@ During development, it may be desirable to use file backed block storage. It
 is possible to use a file and mount it as a block device via the loopback
 system. ::
 
-    mknod /dev/loop2 b 7 2
-    dd if=/dev/zero of=/var/lib/cinder_data.img bs=1G count=20
-    losetup /dev/loop2 /var/lib/cinder_data.img
-    pvcreate /dev/loop2
-    vgcreate cinder-volumes /dev/loop2
+
+    free_device=$(losetup -f)
+    fallocate -l 20G /var/lib/cinder_data.img
+    losetup $free_device /var/lib/cinder_data.img
+    pvcreate $free_device
+    vgcreate cinder-volumes $free_device
 
 Enable the ``lvm`` backend in ``/etc/kolla/globals.yml``: