From 931d49ce582375441ace1c40b8502ae30ba27654 Mon Sep 17 00:00:00 2001
From: Chunjie Zhu <chunjie.zhu@cloud.com>
Date: Tue, 21 Apr 2026 16:27:55 +0800
Subject: [PATCH] CA-395093: miss physical-device-path xenstore key

read physical-device-path from xenstore directly, there is no
synchronization between slave tapback process and xenopsd hotplug
vbd-script, so, in some corner case, slave tapback process would
miss physical-device-path xenstore watch event, then blktap io
datapath fails to be established.

Signed-off-by: Chunjie Zhu <chunjie.zhu@cloud.com>
---
 tapback/backend.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tapback/backend.c b/tapback/backend.c
index facae9bfd..53813e715 100644
--- a/tapback/backend.c
+++ b/tapback/backend.c
@@ -769,6 +769,18 @@ reconnect(vbd_t *device) {
         }
     }
 
+    err = physical_device_path_changed(device);
+    if (err) {
+        if (err == -ENOENT) {
+            DBG(device, "no physical device path yet\n");
+            err = 0;
+        } else {
+            WARN(device, "failed to retrieve physical device path: "
+                    "%s\n", strerror(-err));
+            goto out;
+        }
+    }
+
     err = hotplug_status_changed(device);
     if (err) {
         if (err == -ENOENT) {