doc/lvol: add json rpc description for set_read_only_lvol_bdev() RPC

Change-Id: I1fc27b0b321275104c62d781e80ae1288d33b7cb
Signed-off-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-on: https://review.gerrithub.io/c/441444
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

doc/jsonrpc.md

@@ -297,6 +297,7 @@ Example response:
     "get_lvol_stores",
     "destroy_lvol_bdev",
     "resize_lvol_bdev",
+    "set_read_only_lvol_bdev",
     "decouple_parent_lvol_bdev",
     "inflate_lvol_bdev",
     "rename_lvol_bdev",
@@ -4360,6 +4361,39 @@ Example response:
 }
 ~~~
 
+## set_read_only_lvol_bdev{#rpc_set_read_only_lvol_bdev}
+
+Mark logical volume as read only.
+
+### Parameters
+
+Name                    | Optional | Type        | Description
+----------------------- | -------- | ----------- | -----------
+name                    | Required | string      | UUID or alias of the logical volume to set as read only
+
+### Example
+
+Example request:
+~~~
+{
+  "jsonrpc": "2.0",
+  "method": "set_read_only_lvol_bdev",
+  "id": 1,
+  "params": {
+    "name": "51638754-ca16-43a7-9f8f-294a0805ab0a",
+  }
+}
+~~~
+
+Example response:
+~~~
+{
+  "jsonrpc": "2.0",
+  "id": 1,
+  "result": true
+}
+~~~
+
 ## destroy_lvol_bdev {#rpc_destroy_lvol_bdev}
 
 Destroy a logical volume.