Don't mount raw blktap disks for pygrub

diff -r 3ac19fda0bc2 tools/python/xen/util/blkif.py
@@ -66,16 +66,23 @@ def blkdev_segment(name):
                 'type'         : 'Disk' }
     return val
 
-def blkdev_uname_to_file(uname):
-    """Take a blkdev uname and return the corresponding filename."""
-    fn = None
+def _parse_uname(uname):
+    fn = taptype = None
     if uname.find(":") != -1:
         (typ, fn) = uname.split(":", 1)
         if typ == "phy" and not fn.startswith("/"):
             fn = "/dev/%s" %(fn,)
         if typ == "tap":
-            (typ, fn) = fn.split(":", 1)
-    return fn
+            (taptype, fn) = fn.split(":", 1)
+    return (fn, taptype)
+
+def blkdev_uname_to_file(uname):
+    """Take a blkdev uname and return the corresponding filename."""
+    return _parse_uname(uname)[0]
+
+def blkdev_uname_to_taptype(uname):
+    """Take a blkdev uname and return the blktap type."""
+    return _parse_uname(uname)[1]
 
 def mount_mode(name):
     mode = None

diff -r 3ac19fda0bc2 tools/python/xen/xend/XendDomainInfo.py
@@ -34,7 +34,7 @@ from types import StringTypes
 
 import xen.lowlevel.xc
 from xen.util import asserts
-from xen.util.blkif import blkdev_uname_to_file
+from xen.util.blkif import blkdev_uname_to_file, blkdev_uname_to_taptype
 from xen.util import security
 
 from xen.xend import balloon, sxp, uuid, image, arch, osdep

@@ -1768,7 +1768,8 @@ class XendDomainInfo:
             disk = devinfo[1]['uname']
 
             fn = blkdev_uname_to_file(disk)
-            mounted = devtype == 'tap' and not os.stat(fn).st_rdev
+            taptype = blkdev_uname_to_taptype(disk)
+            mounted = devtype == 'tap' and taptype != 'aio' and taptype != 'sync' and not os.stat(fn).st_rdev
             if mounted:
                 # This is a file, not a device.  pygrub can cope with a
                 # file if it's raw, but if it's QCOW or other such formats

@@ -1784,7 +1785,7 @@ class XendDomainInfo:
 
                 from xen.xend import XendDomain
                 dom0 = XendDomain.instance().privilegedDomain()
-                dom0._waitForDeviceUUID(dom0.create_vbd(vbd, fn))
+                dom0._waitForDeviceUUID(dom0.create_vbd(vbd, disk))
                 fn = BOOTLOADER_LOOPBACK_DEVICE
 
             try: