From c9b6e56e7342a1bb31cfb79f28b6a00d05954006 Mon Sep 17 00:00:00 2001
From: Paul Durrant <paul.durrant@citrix.com>
Date: Mon, 22 Sep 2014 12:02:44 +0100
Subject: [PATCH] Cope with unexpected initial backend states

If the OS is booted via iSCSI, then the backend will already be in the
Connected state when the xenvif driver loads.  The backend is stable
in this state, so __FrontendPrepare() eventually times out waiting for
the backend state to change.

Fix by leading the backend through the Closing and Closed states if we
find it initially in the Connected (or Closing) states.

Signed-off-by: Michael Brown <mbrown@fensystems.co.uk>

Forward ported.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
---
 src/xenvif/frontend.c | 56 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 48 insertions(+), 8 deletions(-)

diff --git a/src/xenvif/frontend.c b/src/xenvif/frontend.c
index d5197c5..305faaf 100644
--- a/src/xenvif/frontend.c
+++ b/src/xenvif/frontend.c
@@ -1029,14 +1029,45 @@ __FrontendPrepare(
     if (!NT_SUCCESS(status))
         goto fail3;
 
+    while (State == XenbusStateConnected) {
+        (VOID) XENBUS_STORE(Printf,
+                            &Frontend->StoreInterface,
+                            NULL,
+                            __FrontendGetPath(Frontend),
+                            "state",
+                            "%u",
+                            XenbusStateClosing);
+        status = __FrontendWaitForStateChange(Frontend, Path, &State);
+        if (!NT_SUCCESS(status))
+            goto fail4;
+    }
+
+    while (State == XenbusStateClosing) {
+        (VOID) XENBUS_STORE(Printf,
+                            &Frontend->StoreInterface,
+                            NULL,
+                            __FrontendGetPath(Frontend),
+                            "state",
+                            "%u",
+                            XenbusStateClosed);
+        status = __FrontendWaitForStateChange(Frontend, Path, &State);
+        if (!NT_SUCCESS(status))
+            goto fail5;
+    }
+
     while (State != XenbusStateClosed &&
            State != XenbusStateInitialising &&
-           State != XenbusStateInitWait) {
+           State != XenbusStateInitWait &&
+           State != XenbusStateUnknown) {
         status = __FrontendWaitForStateChange(Frontend, Path, &State);
         if (!NT_SUCCESS(status))
-            goto fail4;
+            goto fail6;
     }
 
+    status = STATUS_UNSUCCESSFUL;
+    if (State == XenbusStateUnknown)
+        goto fail7;
+
     status = XENBUS_STORE(Printf,
                           &Frontend->StoreInterface,
                           NULL,
@@ -1045,18 +1076,18 @@ __FrontendPrepare(
                           "%u",
                           XenbusStateInitialising);
     if (!NT_SUCCESS(status))
-        goto fail5;
+        goto fail8;
 
     while (State == XenbusStateClosed ||
            State == XenbusStateInitialising) {
         status = __FrontendWaitForStateChange(Frontend, Path, &State);
         if (!NT_SUCCESS(status))
-            goto fail6;
+            goto fail9;
     }
 
     status = STATUS_UNSUCCESSFUL;
     if (State != XenbusStateInitWait)
-        goto fail7;
+        goto fail10;
 
     Frontend->BackendPath = Path;
 
@@ -1083,17 +1114,26 @@ __FrontendPrepare(
                           ThreadGetEvent(Frontend->EjectThread),
                           &Frontend->Watch);
     if (!NT_SUCCESS(status))
-        goto fail8;
+        goto fail11;
 
     Trace("<====\n");
     return STATUS_SUCCESS;
 
-fail8:
-    Error("fail8\n");
+fail11:
+    Error("fail11\n");
 
     Frontend->BackendDomain = DOMID_INVALID;
     Frontend->BackendPath = NULL;
 
+fail10:
+    Error("fail10\n");
+
+fail9:
+    Error("fail9\n");
+
+fail8:
+    Error("fail8\n");
+
 fail7:
     Error("fail7\n");
 
-- 
2.39.5