lxd/metadata: update metadata configuration

Signed-off-by: Gabriel Mougard <[email protected]>

doc/config_options.txt

@@ -808,6 +808,14 @@ The network device MAC address is used when no `hwaddr` property is set on the d
 Possible values are `true` or `false`.
 ```
 
+```{config:option} volatile.<name>.last_state.created_path instance-volatile
+:shortdesc: "Path of the directory created from mounting a `disk` device"
+:type: "string"
+If mounting a host directory through a `disk` device creates the target directory, this option contains the path of this newly created target directory.
+For example, if the target directory is `/opt` and `/opt` already exists in the instance, this key is not set.
+However, if the target directory is `/opt/foo` and `/opt/foo` doesn't exist in the instance, this key is set to `/opt/foo`.
+```
+
 ```{config:option} volatile.<name>.last_state.hwaddr instance-volatile
 :shortdesc: "Network device original MAC"
 :type: "string"

lxd/metadata/configuration.json

@@ -859,6 +859,13 @@
 							"type": "string"
 						}
 					},
+					{
+						"volatile.\u003cname\u003e.last_state.created_path": {
+							"longdesc": "If mounting a host directory through a `disk` device creates the target directory, this option contains the path of this newly created target directory.\nFor example, if the target directory is `/opt` and `/opt` already exists in the instance, this key is not set.\nHowever, if the target directory is `/opt/foo` and `/opt/foo` doesn't exist in the instance, this key is set to `/opt/foo`.",
+							"shortdesc": "Path of the directory created from mounting a `disk` device",
+							"type": "string"
+						}
+					},
 					{
 						"volatile.\u003cname\u003e.last_state.hwaddr": {
 							"longdesc": "The original MAC that was used when moving a physical device into an instance.",