diff --git a/dom0/qvm-tools/qvm-grow-private b/dom0/qvm-tools/qvm-grow-private
index e14802b6..7ca50d2e 100755
--- a/dom0/qvm-tools/qvm-grow-private
+++ b/dom0/qvm-tools/qvm-grow-private
@@ -99,7 +99,7 @@ def main():
         retcode = subprocess.check_call(["losetup", "--set-capacity", loop_dev])
 
         retcode = subprocess.check_call([qvm_run_path, "-uroot", vmname, 
-                "resize2fs /dev/xvdb" ])
+                "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])