Merge pull request #2138 from hellohellenmao/1811588

New case of resize_short_overlay

qemu/tests/cfg/resize_short_overlay.cfg

+- resize_short_overlay:
+    only qcow2
+    virt_test_type = qemu
+    type = resize_short_overlay
+    start_vm = no
+    force_create_image = no
+    remove_image = yes
+    images = "base mid top"
+    image_chain = "base mid top"
+    image_name_base = "images/base"
+    image_size_base = 2M
+    image_format_base = qcow2
+    image_name_mid = "images/mid"
+    image_size_mid = 1M
+    image_format_mid = qcow2
+    image_name_top = "images/top"
+    image_size_top = 2M
+    image_format_top = qcow2
+    # 2M - 1M ($image_size_top - $image_size_mid)
+    diff_size = 1M
+    base_cmd = "write -P1 0 ${image_size_base}"
+    top_cmd = "read -P0 ${image_size_mid} ${diff_size}"

qemu/tests/resize_short_overlay.py

+import logging
+
+from avocado import fail_on
+from avocado.utils import process
+
+from virttest import data_dir
+from virttest.qemu_io import QemuIOSystem
+from virttest.qemu_storage import QemuImg
+
+
+def run(test, params, env):
+    """
+    Check the data after resizing short overlay over longer backing files.
+    1. Create a qcow2 base image.
+    2. Create a middle snapshot file with smaller size.
+    3. Create a top snapshot with the size as the same as the one of base.
+    4. Write '1' to the base image file.
+    5. Check the data of the top image file.
+    6. Commit top image file.
+    7. Check the data in the middle image file.
+    :param test: VT test object.
+    :param params: Dictionary with the test parameters.
+    :param env: Dictionary with test environment.
+    """
+    def _qemu_io(img, cmd):
+        """Run qemu-io cmd to a given img."""
+        logging.info("Run qemu-io %s" % img.image_filename)
+        try:
+            QemuIOSystem(test, params, img.image_filename).cmd_output(cmd, 120)
+        except process.CmdError as err:
+            test.fail("qemu-io to '%s' failed: %s." % (img.image_filename, err))
+
+    images = params["image_chain"].split()
+    root_dir = data_dir.get_data_dir()
+    base = QemuImg(params.object_params(images[0]), root_dir, images[0])
+    mid = QemuImg(params.object_params(images[1]), root_dir, images[1])
+    top = QemuImg(params.object_params(images[-1]), root_dir, images[-1])
+
+    logging.info("Create base and snapshot files")
+    for image in (base, mid, top):
+        image.create(image.params)
+
+    _qemu_io(base, params["base_cmd"])
+
+    top_cmd = params["top_cmd"]
+    _qemu_io(top, top_cmd)
+
+    logging.info("Commit %s image file." % top.image_filename)
+    fail_on((process.CmdError,))(top.commit)()
+
+    _qemu_io(mid, top_cmd)