From be0f96ffadc0ff8dd2cec61e59716683a25d58c9 Mon Sep 17 00:00:00 2001
From: Cheng Pan <chengpan@amazon.com>
Date: Thu, 14 Mar 2019 00:24:17 +0000
Subject: [PATCH] Update CSI migration doc for block volume migration

---
 contributors/design-proposals/storage/csi-migration.md | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/contributors/design-proposals/storage/csi-migration.md b/contributors/design-proposals/storage/csi-migration.md
index ee6dc464c..6990d30cd 100644
--- a/contributors/design-proposals/storage/csi-migration.md
+++ b/contributors/design-proposals/storage/csi-migration.md
@@ -292,8 +292,14 @@ existing Pods in the ADC.
 TODO: Design
 
 ### Raw Block
+In the OperationGenerator, `GenerateMapVolumeFunc`, `GenerateUnmapVolumeFunc` and 
+`GenerateUnmapDeviceFunc` are used to prepare and mount/umount block devices. At the 
+beginning of each API, we will check whether migration is enabled for the plugin. If
+enabled, volume spec will be translated from the in-tree spec to out-of-tree spec using
+CSI as the persistence volume source.
 
-TODO: Design
+Caveat: the original spec needs to be used when setting the state of `actualStateOfWorld`
+for where is it used before the translation.
 
 ### Volume Reconstruction