diff --git a/dom0/qvm-core/qubes.py b/dom0/qvm-core/qubes.py
index 3d6b88c2..333212e8 100755
--- a/dom0/qvm-core/qubes.py
+++ b/dom0/qvm-core/qubes.py
@@ -640,10 +640,35 @@ class QubesVm(object):
         return os.path.getsize(self.private_img)
 
     def resize_private_img(self, size):
+        assert size >= self.get_private_img_sz(), "Cannot shrink private.img"
+
         f_private = open (self.private_img, "a+b")
         f_private.truncate (size)
         f_private.close ()
 
+        retcode = 0
+        if self.is_running():
+            # find loop device
+            p = subprocess.Popen (["losetup", "--associated", vm.private_img],
+                    stdout=subprocess.PIPE)
+            result = p.communicate()
+            m = re.match(r"^(/dev/loop\d+):\s", result[0])
+            if m is None:
+                raise QubesException("ERROR: Cannot find loop device!")
+
+            loop_dev = m.group(1)
+
+            # resize loop device
+            subprocess.check_call(["sudo", "losetup", "--set-capacity", loop_dev])
+
+            retcode = self.run("root:while [ \"`blockdev --getsize64 /dev/xvdb`\" -lt {0} ]; do " +
+                "head /dev/xvdb > /dev/null; sleep 0.2; done; resize2fs /dev/xvdb".format(size_bytes), wait=True)
+        else:
+            retcode = subprocess.check_call(["sudo", "resize2fs", "-f", vm.private_img])
+        if retcode != 0:
+            raise QubesException("resize2fs failed")
+
+
     # FIXME: should be outside of QubesVM?
     def get_timezone(self):
         clock_config = open('/etc/sysconfig/clock', "r")
diff --git a/dom0/qvm-tools/qvm-grow-private b/dom0/qvm-tools/qvm-grow-private
index 5e778c1c..b9a5a996 100755
--- a/dom0/qvm-tools/qvm-grow-private
+++ b/dom0/qvm-tools/qvm-grow-private
@@ -51,42 +51,14 @@ def main():
         print >> sys.stderr, "A VM with the name '{0}' does not exist in the system.".format(vmname)
         exit(1)
 
-    if vm.is_running() and os.geteuid() != 0:
-        print >> sys.stderr, "You must be root to grow private.img on running VM."
-        exit(1)
-
     size_bytes = parse_size(size)
 
-    if size_bytes < vm.get_private_img_sz():
-        print >> sys.stderr, "Cannot shrink private.img ({0} < {1})".format(size_bytes, vm.get_private_img_sz())
-        exit(1)
-
     try:
         vm.resize_private_img(size_bytes)
     except (IOError, OSError, QubesException) as err:
         print >> sys.stderr, "ERROR: {0}".format(err)
         exit (1)
 
-    if vm.is_running():
-        # find loop device
-        p = subprocess.Popen (["losetup", "--associated", vm.private_img],
-                stdout=subprocess.PIPE)
-        result = p.communicate()
-        m = re.match(r"^(/dev/loop\d+):\s", result[0])
-        if m is None:
-            print >> sys.stderr, "ERROR: Cannot find loop device!"
-            exit(1)
-
-        loop_dev = m.group(1)
-
-        # resize loop device
-        retcode = subprocess.check_call(["losetup", "--set-capacity", loop_dev])
-
-        retcode = subprocess.check_call([qvm_run_path, "-uroot", "--pass-io", vmname, 
-                "while [ \"`blockdev --getsize64 /dev/xvdb`\" -lt {0} ]; do sleep 0.2; done; resize2fs /dev/xvdb".format(size_bytes) ])
-    else:
-        retcode = subprocess.check_call(["resize2fs", "-f", vm.private_img])
-        
 	exit (0)