xend: Remember bootable flag for vbds in xenstore

When xend is restarted, bootable flags of all disk devices are lost
and then the first disk is marked as bootable by a "compatibility
hack". When a guest domain is created with a mixture of several vbd
and tap devices, the compatibility hack may fail to choose the right
bootable device. Thus preventing the guest to be restarted. This patch
fixes this behavior by remembering bootable flag for each disk device
in xenstore database.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

tools/python/xen/xend/XendConfig.py

@@ -1289,7 +1289,6 @@ class XendConfig(dict):
                     pass
 
             if dev_type == 'vbd':
-                dev_info['bootable'] = 0
                 if dev_info.get('dev', '').startswith('ioemu:'):
                     dev_info['driver'] = 'ioemu'
                 else:
@@ -1325,7 +1324,7 @@ class XendConfig(dict):
                 if param not in target:
                     target[param] = []
                 if dev_uuid not in target[param]:
-                    if dev_type == 'vbd':
+                    if dev_type == 'vbd' and 'bootable' not in dev_info:
                         # Compat hack -- mark first disk bootable
                         dev_info['bootable'] = int(not target[param])
                     target[param].append(dev_uuid)
@@ -1333,8 +1332,9 @@ class XendConfig(dict):
                 if 'vbd_refs' not in target:
                     target['vbd_refs'] = []
                 if dev_uuid not in target['vbd_refs']:
-                    # Compat hack -- mark first disk bootable
-                    dev_info['bootable'] = int(not target['vbd_refs'])
+                    if 'bootable' not in dev_info:
+                        # Compat hack -- mark first disk bootable
+                        dev_info['bootable'] = int(not target['vbd_refs'])
                     target['vbd_refs'].append(dev_uuid)
                     
             elif dev_type == 'vfb':

tools/python/xen/xend/server/blkif.py

@@ -78,6 +78,10 @@ class BlkifController(DevController):
         if uuid:
             back['uuid'] = uuid
 
+        bootable = config.get('bootable', None)
+        if bootable != None:
+            back['bootable'] = str(bootable)
+
         if security.on() == xsconstants.XS_POLICY_USE:
             self.do_access_control(config, uname)
 
@@ -143,11 +147,12 @@ class BlkifController(DevController):
         config = DevController.getDeviceConfiguration(self, devid, transaction)
         if transaction is None:
             devinfo = self.readBackend(devid, 'dev', 'type', 'params', 'mode',
-                                       'uuid')
+                                       'uuid', 'bootable')
         else:
             devinfo = self.readBackendTxn(transaction, devid,
-                                          'dev', 'type', 'params', 'mode', 'uuid')
-        dev, typ, params, mode, uuid = devinfo
+                                          'dev', 'type', 'params', 'mode', 'uuid',
+                                          'bootable')
+        dev, typ, params, mode, uuid, bootable = devinfo
         
         if dev:
             if transaction is None:
@@ -165,6 +170,8 @@ class BlkifController(DevController):
             config['mode'] = mode
         if uuid:
             config['uuid'] = uuid
+        if bootable != None:
+            config['bootable'] = int(bootable)
 
         proto = self.readFrontend(devid, 'protocol')
         if proto: