From 458052b5ecb466194cd972f06bc72ee945fa92fa Mon Sep 17 00:00:00 2001
From: "jchesterfield@dhcp92.uk.xensource.com"
 <jchesterfield@dhcp92.uk.xensource.com>
Date: Wed, 30 Aug 2006 11:39:27 +0100
Subject: [PATCH] Block IO safety patch for live migration. Xend checks that
 VBDs are destroyed before unpausing the domain.

---
 tools/python/xen/xend/XendCheckpoint.py |  6 ++++--
 tools/python/xen/xend/XendDomain.py     |  3 ++-
 tools/python/xen/xend/XendDomainInfo.py | 15 +++++++++++++++
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/python/xen/xend/XendCheckpoint.py b/tools/python/xen/xend/XendCheckpoint.py
index 6801f3cd40..9fd3169a9d 100644
--- a/tools/python/xen/xend/XendCheckpoint.py
+++ b/tools/python/xen/xend/XendCheckpoint.py
@@ -161,10 +161,12 @@ def restore(xd, fd):
         if handler.store_mfn is None or handler.console_mfn is None:
             raise XendError('Could not read store/console MFN')
 
+	#Block until src closes connection
+	os.read(fd, 1)
         dominfo.unpause()
-
+        
         dominfo.completeRestore(handler.store_mfn, handler.console_mfn)
-
+        
         return dominfo
     except:
         dominfo.destroy()
diff --git a/tools/python/xen/xend/XendDomain.py b/tools/python/xen/xend/XendDomain.py
index bbdfd62ab9..af4c474b94 100644
--- a/tools/python/xen/xend/XendDomain.py
+++ b/tools/python/xen/xend/XendDomain.py
@@ -431,7 +431,8 @@ class XendDomain:
         sock.send("receive\n")
         sock.recv(80)
         XendCheckpoint.save(sock.fileno(), dominfo, True, live, dst)
-
+	dominfo.testDeviceComplete()
+	sock.close()
 
     def domain_save(self, domid, dst):
         """Start saving a domain to file.
diff --git a/tools/python/xen/xend/XendDomainInfo.py b/tools/python/xen/xend/XendDomainInfo.py
index a7a388bbea..48ff0ff291 100644
--- a/tools/python/xen/xend/XendDomainInfo.py
+++ b/tools/python/xen/xend/XendDomainInfo.py
@@ -1494,6 +1494,21 @@ class XendDomainInfo:
             if rc != 0:
                 raise XendError("Device of type '%s' refuses migration." % n)
 
+    def testDeviceComplete(self):
+        """ For Block IO migration safety we must ensure that
+        the device has shutdown correctly, i.e. all blocks are
+        flushed to disk
+        """
+        while True:
+            test = 0
+            for i in self.getDeviceController('vbd').deviceIDs():
+                test = 1
+                log.info("Dev %s still active, looping...", i)
+                time.sleep(0.1)
+                
+            if test == 0:
+                break
+
     def migrateDevices(self, network, dst, step, domName=''):
         """Notify the devices about migration
         """
-- 
2.30.2