From a16ba7fbb864ed07b1ede878a6cff013253aa677 Mon Sep 17 00:00:00 2001
From: Blair Zajac <blair@orcaware.com>
Date: Sun, 17 Mar 2013 15:30:16 -0700
Subject: [PATCH 1/2] ec2_vol: update docs to match default device_name values
 for Unix/Windows.

---
 ec2_vol | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ec2_vol b/ec2_vol
index e6f29e6ba01..8e6da4eb042 100644
--- a/ec2_vol
+++ b/ec2_vol
@@ -36,7 +36,7 @@ options:
     aliases: []
   device_name:
     description:
-      - device id to override device mapping. Assumes /dev/sdf for instance-store, /dev/sdb for EBS.
+      - device id to override device mapping. Assumes /dev/sdf for Linux/UNIX and /dev/xvdf for Windows.
     required: false
     default: null
     aliases: []

From 91b7d4b0696d3ae54c611a34f7aff5163d8ca453 Mon Sep 17 00:00:00 2001
From: Blair Zajac <blair@orcaware.com>
Date: Sun, 17 Mar 2013 15:46:33 -0700
Subject: [PATCH 2/2] ec2_vol: do no work if the instance has a volume mounted
 at the device.

---
 ec2_vol | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/ec2_vol b/ec2_vol
index 8e6da4eb042..f2d41657364 100644
--- a/ec2_vol
+++ b/ec2_vol
@@ -19,7 +19,7 @@ DOCUMENTATION = '''
 module: ec2_vol
 short_description: create and attach a volume, return volume id and device map
 description:
-    - creates an EBS volume and optionally attaches it to an instance. This module has a dependency on python-boto
+    - creates an EBS volume and optionally attaches it to an instance.  If both an instance ID and a device name is given and the instance has a device at the device name, then no volume is created and no attachment is made.  This module has a dependency on python-boto.
 version_added: "1.1"
 options:
   instance:
@@ -123,6 +123,12 @@ def main():
         inst = reservation[0].instances[0]
         zone = inst.placement
 
+        # Check if there is a volume already mounted there.
+        if device_name:
+            if device_name in inst.block_device_mapping:
+                module.exit_json(msg="Volume mapping for %s already exists on instance %s" % (device_name, instance),
+                                 changed=False)
+
     # If no instance supplied, try volume creation based on module parameters.
 
     try: