block: make 'top' argument to block-commit optional

Now that active layer block-commit is supported, the 'top' argument
no longer needs to be mandatory.

Change it to optional, with the default being the active layer in the
device chain.

[kwolf: Rebased and resolved conflict in tests/qemu-iotests/040]

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 7676e2c597000eff3a7233b40cca768b358f9bc9)

Conflicts:
	qapi/block-core.json

*removed dependency on 1ad166b6

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

1 files changed, 18 insertions, 10 deletions

diff --git a/tests/qemu-iotests/040 b/tests/qemu-iotests/040
index d1668109dd..f1e16c11c7 100755
--- a/tests/qemu-iotests/040
+++ b/tests/qemu-iotests/040
@@ -35,11 +35,7 @@ test_img = os.path.join(iotests.test_dir, 'test.img')
 class ImageCommitTestCase(iotests.QMPTestCase):
     '''Abstract base class for image commit test cases'''
 
-    def run_commit_test(self, top, base, need_ready=False):
-        self.assert_no_active_block_jobs()
-        result = self.vm.qmp('block-commit', device='drive0', top=top, base=base)
-        self.assert_qmp(result, 'return', {})
-
+    def wait_for_complete(self, need_ready=False):
         completed = False
         ready = False
         while not completed:
@@ -62,6 +58,18 @@ class ImageCommitTestCase(iotests.QMPTestCase):
         self.assert_no_active_block_jobs()
         self.vm.shutdown()
 
+    def run_commit_test(self, top, base, need_ready=False):
+        self.assert_no_active_block_jobs()
+        result = self.vm.qmp('block-commit', device='drive0', top=top, base=base)
+        self.assert_qmp(result, 'return', {})
+        self.wait_for_complete(need_ready)
+
+    def run_default_commit_test(self):
+        self.assert_no_active_block_jobs()
+        result = self.vm.qmp('block-commit', device='drive0')
+        self.assert_qmp(result, 'return', {})
+        self.wait_for_complete()
+
 class TestSingleDrive(ImageCommitTestCase):
     image_len = 1 * 1024 * 1024
     test_len = 1 * 1024 * 256
@@ -113,17 +121,17 @@ class TestSingleDrive(ImageCommitTestCase):
         self.assertEqual(-1, qemu_io('-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
         self.assertEqual(-1, qemu_io('-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
 
+    def test_top_is_default_active(self):
+        self.run_default_commit_test()
+        self.assertEqual(-1, qemu_io('-c', 'read -P 0xab 0 524288', backing_img).find("verification failed"))
+        self.assertEqual(-1, qemu_io('-c', 'read -P 0xef 524288 524288', backing_img).find("verification failed"))
+
     def test_top_and_base_reversed(self):
         self.assert_no_active_block_jobs()
         result = self.vm.qmp('block-commit', device='drive0', top='%s' % backing_img, base='%s' % mid_img)
         self.assert_qmp(result, 'error/class', 'GenericError')
         self.assert_qmp(result, 'error/desc', 'Base \'%s\' not found' % mid_img)
 
-    def test_top_omitted(self):
-        self.assert_no_active_block_jobs()
-        result = self.vm.qmp('block-commit', device='drive0')
-        self.assert_qmp(result, 'error/class', 'GenericError')
-        self.assert_qmp(result, 'error/desc', "Parameter 'top' is missing")
 
 class TestRelativePaths(ImageCommitTestCase):
     image_len = 1 * 1024 * 1024