qemu_storage: Stop ignoring failures creating VM images

By default, the qemu_storage code is ignoring failures
when qemu-img fails to create a disk image. This happens
because the failure is actually considered only if the
(terribly undocumented) param 'check_output' is set to
yes.

Since there's no 'check_output' on any .cfg file
in the virt-test repo, the failures will never be
considered and virt-tests will happily proceed, even
though a world of pain and suffering will follow.

Since there are future tests that might require the
output of the creation command, we'll fix the problem
by:

1) Introducing a ignore_errors boolean parameter to
the .create() method, when set to true it'll make
the method to not raise an error on failure.

2) Making the method return a fixed tuple
(path to the image created, object with the result
of the command). With the result object, it is easy
to get outputs as they are attributes of the said
object.

This also has the nice side effect of not requiring
the check_output parameter anymore.

Signed-off-by: Lucas Meneghel Rodrigues <[email protected]>

qemu/tests/qemu_io_blkdebug.py

@@ -33,7 +33,7 @@ def run_qemu_io_blkdebug(test, params, env):
 
     error.context("Create image", logging.info)
     image_io = QemuImg(params.object_params(image), test.bindir, image)
-    image_name = image_io.create(params.object_params(image))
+    image_name, _ = image_io.create(params.object_params(image))
 
     template_name =  utils_misc.get_path(test.virtdir, blkdebug_default)
     template = ConfigParser.ConfigParser()

virttest/env_process.py

@@ -45,8 +45,8 @@ def preprocess_image(test, params, image_name):
 
         if create_image:
             image = qemu_storage.QemuImg(params, base_dir, image_name)
-            if not image.create(params):
-                raise error.TestError("Could not create image")
+            image.create(params)
+
 
 def preprocess_vm(test, params, env, name):
     """

virttest/qemu_storage.py

@@ -31,11 +31,13 @@ def __init__(self, params, root_dir, tag):
                                  params.get("qemu_img_binary","qemu-img"))
 
 
-    def create(self, params):
+    def create(self, params, ignore_errors=False):
         """
         Create an image using qemu_img or dd.
 
         @param params: Dictionary containing the test parameters.
+        @param ignore_errors: Whether to ignore errors on the image creation
+                cmd.
 
         @note: params should contain:
                image_name -- the name of the image file, without extension
@@ -51,6 +53,9 @@ def create(self, params):
                values: on and off. Default is "off"
                preallocated(optional) -- if preallocation when create image,
                allowed values: off, metadata. Default is "off"
+
+        @return: tuple (path to the image created, utils.CmdResult object
+                containing the result of the creation command).
         """
         if params.get("create_with_dd") == "yes" and self.image_format == "raw":
             # maps K,M,G,T => (count, bs)
@@ -95,21 +100,12 @@ def create(self, params):
 
             qemu_img_cmd += " %s" % self.size
 
-        check_output = params.get("check_output") == "yes"
-        try:
-            result = utils.run(qemu_img_cmd, verbose=False)
-        except error.CmdError, e:
-            logging.error("Could not create image, failed with error message:"
-                            "%s", str(e))
-            if not check_output:
-                result = None
-            else:
-                result = str(e)
-        if not check_output:
-            result = self.image_filename
-
-        return result
+        cmd_result = utils.run(qemu_img_cmd, verbose=False, ignore_status=True)
+        if cmd_result.exit_status != 0 and not ignore_errors:
+            raise error.TestError("Failed to create image %s" %
+                                  self.image_filename)
 
+        return self.image_filename, cmd_result
 
 
     def convert(self, params, root_dir):