From dbd85ee88c92ae3fa579d8cfd6ef93a5c7783a3a Mon Sep 17 00:00:00 2001
From: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Date: Fri, 4 Aug 2023 15:11:39 +0200
Subject: [PATCH] docs: add pnfs flow diagram

---
 modules/dcache-nfs/README.md | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 modules/dcache-nfs/README.md

diff --git a/modules/dcache-nfs/README.md b/modules/dcache-nfs/README.md
new file mode 100644
index 00000000000..ac786fca74d
--- /dev/null
+++ b/modules/dcache-nfs/README.md
@@ -0,0 +1,27 @@
+# NFSv4.1/pNFS Door
+
+
+```mermaid
+sequenceDiagram
+    autonumber
+    actor Client
+    participant Door
+    participant poolA
+    participant PoolManager
+    Client->>Door: OPEN(file), LAYOUTGET 
+    Door->>PoolManager: Select Pool
+    PoolManager-->>Door: 'poolA'
+    Door->>poolA: Start Mover (state)
+    poolA-->>Door: Ready(id)
+    Door-->>Client: 'open state', 'layout'
+    loop Application IO
+        Client->>poolA: READ(file, state, offset, len)
+        poolA-->>Client: 'bytes'
+    end
+    Client->>Door: LAYOUT_RETURN, CLOSE
+    Door->>poolA: Kill Mover(id)
+    poolA->>poolA: state invalidated
+    poolA-->>Door: Trnaster Finish
+    Door->>Door: Invalidate state
+    Door-->>Client: OK
+```
\ No newline at end of file