vmdk: Reject excess extents in blockdev-create

Clarify that the number of extents provided in BlockdevCreateOptionsVmdk
must match the number of extents that will actually be used. Providing
more extents will result in an error now.

This requires adapting the test case to provide the right number of
extents.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

tests/qemu-iotests/237

@@ -20,6 +20,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 
+import math
 import iotests
 from iotests import imgfmt
 
@@ -222,12 +223,15 @@ with iotests.FilePath('t.vmdk') as disk_path, \
             iotests.log("= %s %d =" % (subfmt, size))
             iotests.log("")
 
+            num_extents = math.ceil(size / 2.0**31)
+            extents = [ "ext%d" % (i) for i in range(1, num_extents + 1) ]
+
             vm.launch()
             blockdev_create(vm, { 'driver': imgfmt,
                                   'file': 'node0',
                                   'size': size,
                                   'subformat': subfmt,
-                                  'extents': ['ext1', 'ext2', 'ext3'] })
+                                  'extents': extents })
             vm.shutdown()
 
             iotests.img_info_log(disk_path)