cc_resizefs on FreeBSD: Fix _can_skip_ufs_resize (#655)

On FreeBSD, if a UFS has trim: (-t) or MAC multilabel: (-l) flag, resize
FS fail, because the _can_skip_ufs_resize check gets tripped up by the
missing options.

This was reported at FreeBSD Bugzilla: 
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=250496 and as
LP: #1901958

Rather than fixing the parser as in the patches proposed there (and
attempted in #636) this pull-request rips out all of it, and simplifies
the code.  We now use `growfs -N` and check if that returns an error. If
it returns the correct kind of error, we can skip the resize, because we
either are at the correct size, or the filesystem in question is broken
or not UFS. If it returns the wrong kind of error, we just re-raise it.

LP: #1901958

1 files changed, 26 insertions, 29 deletions

diff --git a/tests/unittests/test_handler/test_handler_resizefs.py b/tests/unittests/test_handler/test_handler_resizefs.py
index db9a0414..28d55072 100644
--- a/tests/unittests/test_handler/test_handler_resizefs.py
+++ b/tests/unittests/test_handler/test_handler_resizefs.py
@@ -6,8 +6,8 @@ from cloudinit.config.cc_resizefs import (
 
 from collections import namedtuple
 import logging
-import textwrap
 
+from cloudinit.subp import ProcessExecutionError
 from cloudinit.tests.helpers import (
     CiTestCase, mock, skipUnlessJsonSchema, util, wrap_and_call)
 
@@ -22,44 +22,41 @@ class TestResizefs(CiTestCase):
         super(TestResizefs, self).setUp()
         self.name = "resizefs"
 
-    @mock.patch('cloudinit.config.cc_resizefs._get_dumpfs_output')
-    @mock.patch('cloudinit.config.cc_resizefs._get_gpart_output')
-    def test_skip_ufs_resize(self, gpart_out, dumpfs_out):
+    @mock.patch('cloudinit.subp.subp')
+    def test_skip_ufs_resize(self, m_subp):
         fs_type = "ufs"
         resize_what = "/"
         devpth = "/dev/da0p2"
-        dumpfs_out.return_value = (
-            "# newfs command for / (/dev/label/rootfs)\n"
-            "newfs -O 2 -U -a 4 -b 32768 -d 32768 -e 4096 "
-            "-f 4096 -g 16384 -h 64 -i 8192 -j -k 6408 -m 8 "
-            "-o time -s 58719232 /dev/label/rootfs\n")
-        gpart_out.return_value = textwrap.dedent("""\
-            =>      40  62914480  da0  GPT  (30G)
-                    40      1024    1  freebsd-boot  (512K)
-                  1064  58719232    2  freebsd-ufs  (28G)
-              58720296   3145728    3  freebsd-swap  (1.5G)
-              61866024   1048496       - free -  (512M)
-            """)
+        err = ("growfs: requested size 2.0GB is not larger than the "
+               "current filesystem size 2.0GB\n")
+        exception = ProcessExecutionError(stderr=err, exit_code=1)
+        m_subp.side_effect = exception
         res = can_skip_resize(fs_type, resize_what, devpth)
         self.assertTrue(res)
 
-    @mock.patch('cloudinit.config.cc_resizefs._get_dumpfs_output')
-    @mock.patch('cloudinit.config.cc_resizefs._get_gpart_output')
-    def test_skip_ufs_resize_roundup(self, gpart_out, dumpfs_out):
+    @mock.patch('cloudinit.subp.subp')
+    def test_cannot_skip_ufs_resize(self, m_subp):
         fs_type = "ufs"
         resize_what = "/"
         devpth = "/dev/da0p2"
-        dumpfs_out.return_value = (
-            "# newfs command for / (/dev/label/rootfs)\n"
-            "newfs -O 2 -U -a 4 -b 32768 -d 32768 -e 4096 "
-            "-f 4096 -g 16384 -h 64 -i 8192 -j -k 368 -m 8 "
-            "-o time -s 297080 /dev/label/rootfs\n")
-        gpart_out.return_value = textwrap.dedent("""\
-            =>      34  297086  da0  GPT  (145M)
-                    34  297086    1  freebsd-ufs  (145M)
-            """)
+        m_subp.return_value = (
+            ("stdout: super-block backups (for fsck_ffs -b #) at:\n\n"),
+            ("growfs: no room to allocate last cylinder group; "
+             "leaving 364KB unused\n")
+        )
         res = can_skip_resize(fs_type, resize_what, devpth)
-        self.assertTrue(res)
+        self.assertFalse(res)
+
+    @mock.patch('cloudinit.subp.subp')
+    def test_cannot_skip_ufs_growfs_exception(self, m_subp):
+        fs_type = "ufs"
+        resize_what = "/"
+        devpth = "/dev/da0p2"
+        err = "growfs: /dev/da0p2 is not clean - run fsck.\n"
+        exception = ProcessExecutionError(stderr=err, exit_code=1)
+        m_subp.side_effect = exception
+        with self.assertRaises(ProcessExecutionError):
+            can_skip_resize(fs_type, resize_what, devpth)
 
     def test_can_skip_resize_ext(self):
         self.assertFalse(can_skip_resize('ext', '/', '/dev/sda1'))