From 8d1913a8cc47c11ff53abe39c6a782ef48ede1c7 Mon Sep 17 00:00:00 2001
From: Rusty Bird <rustybird@net-c.com>
Date: Tue, 11 Sep 2018 23:50:26 +0000
Subject: [PATCH] app: create /var/lib/qubes as file-reflink if supported

Use the file-reflink storage driver if /var/lib/qubes is on a filesystem
that supports reflinks, e.g. when the btrfs layout was selected in
Anaconda. If it doesn't support reflinks (or if detection fails, e.g. in
an unprivileged test environment), use 'file' as before.
---
 qubes/app.py           | 12 +++++++++++-
 qubes/config.py        |  3 +--
 qubes/tests/storage.py |  6 ++++--
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/qubes/app.py b/qubes/app.py
index 3609b6b1..7a31e822 100644
--- a/qubes/app.py
+++ b/qubes/app.py
@@ -61,6 +61,7 @@ import qubes
 import qubes.ext
 import qubes.utils
 import qubes.storage
+import qubes.storage.reflink
 import qubes.vm
 import qubes.vm.adminvm
 import qubes.vm.qubesvm
@@ -553,7 +554,7 @@ def _default_pool(app):
 
     1. If there is one named 'default', use it.
     2. Check if root fs is on LVM thin - use that
-    3. Look for file-based pool pointing /var/lib/qubes
+    3. Look for file(-reflink)-based pool pointing to /var/lib/qubes
     4. Fail
     '''
     if 'default' in app.pools:
@@ -1079,6 +1080,15 @@ class Qubes(qubes.PropertyHolder):
             pool_configs[lvm_config['name']] = lvm_config
 
         for name, config in pool_configs.items():
+            if 'driver' not in config and 'dir_path' in config:
+                config['driver'] = 'file'
+                try:
+                    os.makedirs(config['dir_path'], exist_ok=True)
+                    if qubes.storage.reflink.is_supported(config['dir_path']):
+                        config['driver'] = 'file-reflink'
+                        config['setup_check'] = 'no'  # don't check twice
+                except PermissionError:  # looks like a testing environment
+                    pass  # stay with 'file'
             self.pools[name] = self._get_pool(**config)
 
         self.default_pool_kernel = 'linux-kernel'
diff --git a/qubes/config.py b/qubes/config.py
index dfedfe23..da02dbb6 100644
--- a/qubes/config.py
+++ b/qubes/config.py
@@ -76,9 +76,8 @@ defaults = {
     'root_img_size': 10*1024*1024*1024,
 
     'pool_configs': {
-        # create file pool even when the default one is LVM
+        # create file(-reflink) pool even when the default one is LVM
         'varlibqubes': {'dir_path': qubes_base_dir,
-                    'driver': 'file',
                     'name': 'varlibqubes'},
         'linux-kernel': {
             'dir_path': os.path.join(qubes_base_dir,
diff --git a/qubes/tests/storage.py b/qubes/tests/storage.py
index 1af72a08..97d5932f 100644
--- a/qubes/tests/storage.py
+++ b/qubes/tests/storage.py
@@ -22,6 +22,7 @@ import qubes.storage
 from qubes.exc import QubesException
 from qubes.storage import pool_drivers
 from qubes.storage.file import FilePool
+from qubes.storage.reflink import ReflinkPool
 from qubes.tests import SystemTestCase
 
 # :pylint: disable=invalid-name
@@ -107,10 +108,11 @@ class TC_00_Pool(SystemTestCase):
             pool_drivers())
 
     def test_002_get_pool_klass(self):
-        """ Expect the default pool to be `FilePool` """
+        """ Expect the default pool to be `FilePool` or `ReflinkPool` """
         # :pylint: disable=protected-access
         result = self.app.get_pool('varlibqubes')
-        self.assertIsInstance(result, FilePool)
+        self.assertTrue(isinstance(result, FilePool)
+                        or isinstance(result, ReflinkPool))
 
     def test_003_pool_exists_default(self):
         """ Expect the default pool to exists """