diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 9f604eed937b0a8c6515fe2c89f05a1ecfc42b17..175c1fc7702a347957c15d8bbcdcef7e33696c80 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -7700,7 +7700,7 @@ class LUGrowDisk(LogicalUnit):
 
     self.instance = instance
 
-    if instance.disk_template not in (constants.DT_PLAIN, constants.DT_DRBD8):
+    if instance.disk_template not in constants.DTS_GROWABLE:
       raise errors.OpPrereqError("Instance's disk layout does not support"
                                  " growing.", errors.ECODE_INVAL)
 
diff --git a/lib/constants.py b/lib/constants.py
index 49fca781c15eaf984dfa6370b7924b7025fb0ffe..f841471102253247fcd8d8d08fdae0b3acd829c2 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -265,6 +265,9 @@ DTS_NET_MIRROR = frozenset([DT_DRBD8])
 # the set of non-lvm-based disk templates
 DTS_NOT_LVM = frozenset([DT_DISKLESS, DT_FILE])
 
+# the set of disk templates which can be grown
+DTS_GROWABLE = frozenset([DT_PLAIN, DT_DRBD8])
+
 # logical disk types
 LD_LV = "lvm"
 LD_DRBD8 = "drbd8"
diff --git a/tools/burnin b/tools/burnin
index 91aae6b5c06d5bbefb2a0b2f57c2470a4423ea5b..a7ca79a8cfbd624528263b0e3465158486dfedbc 100755
--- a/tools/burnin
+++ b/tools/burnin
@@ -961,7 +961,7 @@ class Burner(object):
           opts.disk_template in constants.DTS_NET_MIRROR) :
         self.BurnReplaceDisks2()
 
-      if (opts.disk_template != constants.DT_DISKLESS and
+      if (opts.disk_template in constants.DTS_GROWABLE and
           utils.any(self.disk_growth, lambda n: n > 0)):
         self.BurnGrowDisks()