Merge pull request #2838 from OSInside/fix_root_reference_in_snapshot_root

Fix mount system for root_is_snapper_snapshot

Author: schaefi

build-tests/x86/tumbleweed/test-image-MicroOS/appliance.kiwi

@@ -136,8 +136,8 @@
         <package name="coreutils"/>
         <package name="grep"/>
         <package name="gzip"/>
-        <package name="udev"/>
         <package name="xz"/>
+        <package name="libz1"/>
         <package name="shadow"/>
         <package name="filesystem"/>
         <package name="glibc-locale"/>

build-tests/x86/tumbleweed/test-image-MicroOS/disk.sh

@@ -2,3 +2,9 @@
 set -euxo pipefail
 
 /usr/libexec/setup-etc-subvol
+
+# test if there is a proper / mountpoint reference
+findmnt -no UUID /
+
+# show layout
+findmnt

kiwi/volume_manager/btrfs.py

@@ -94,6 +94,7 @@ def post_init(self, custom_args):
 
         self.subvol_mount_list = []
         self.toplevel_mount = None
+        self.snapshots_root_mount = None
 
     def setup(self, name=None):
         """
@@ -162,6 +163,10 @@ def setup(self, name=None):
                 mountpoint=snapshot + '/.snapshots'
             )
             self.subvol_mount_list.append(snapshots_mount)
+            # make sure the snapshot appears as proper (/) in the chroot
+            self.snapshots_root_mount = MountManager(
+                device=self.get_mountpoint(), mountpoint=self.get_mountpoint()
+            )
         elif self.root_volume_name != '/':
             self._set_default_volume(self.root_volume_name)
 
@@ -362,6 +367,8 @@ def mount_volumes(self):
         for volume_mount in self.subvol_mount_list:
             if not os.path.exists(volume_mount.mountpoint):
                 Path.create(volume_mount.mountpoint)
+            if self.snapshots_root_mount:
+                self.snapshots_root_mount.bind_mount()
             subvol_path = volume_mount.get_attributes().get('subvol_path')
             subvol_options = ','.join(
                 [
@@ -380,6 +387,9 @@ def umount_volumes(self) -> None:
             if volume_mount.is_mounted():
                 volume_mount.umount()
 
+        if self.snapshots_root_mount and self.snapshots_root_mount.is_mounted():
+            self.snapshots_root_mount.umount()
+
         if self.toplevel_mount.is_mounted():
             self.toplevel_mount.umount()
 

test/unit/volume_manager/btrfs_test.py

@@ -155,6 +155,10 @@ def test_setup_with_snapshot(
                     'subvol_name': '@/.snapshots'
                 },
                 mountpoint='tmpdir/@/.snapshots/1/snapshot/.snapshots'
+            ),
+            call(
+                device='tmpdir/@/.snapshots/1/snapshot',
+                mountpoint='tmpdir/@/.snapshots/1/snapshot'
             )
         ]
         toplevel_mount.mount.assert_called_once_with([])
@@ -377,6 +381,7 @@ def test_mount_volumes(self, mock_path, mock_os_exists):
             return_value=False
         )
         mock_os_exists.return_value = False
+        self.volume_manager.snapshots_root_mount = Mock()
         volume_mount = Mock()
         volume_mount.mountpoint = \
             '/var/tmp/kiwi_volumes.xx/@/.snapshots/1/snapshot/var/tmp'
@@ -388,6 +393,7 @@ def test_mount_volumes(self, mock_path, mock_os_exists):
 
         self.volume_manager.mount_volumes()
 
+        self.volume_manager.snapshots_root_mount.bind_mount.assert_called_once_with()
         self.volume_manager.toplevel_mount.mount.assert_called_once_with([])
         mock_path.assert_called_once_with(volume_mount.mountpoint)
         volume_mount.mount.assert_called_once_with(
@@ -403,10 +409,18 @@ def test_umount_volumes(self):
         self.volume_manager.toplevel_mount.is_mounted = Mock(
             return_value=True
         )
+        self.volume_manager.snapshots_root_mount = Mock()
+        self.volume_manager.snapshots_root_mount.is_mounted = Mock(
+            return_value=True
+        )
         self.volume_manager.subvol_mount_list = [volume_mount]
+
         self.volume_manager.umount_volumes()
+
         volume_mount.is_mounted.assert_called_once_with()
         volume_mount.umount.assert_called_once_with()
+        self.volume_manager.snapshots_root_mount.is_mounted.assert_called_once_with()
+        self.volume_manager.snapshots_root_mount.umount.assert_called_once_with()
         self.volume_manager.toplevel_mount.is_mounted.assert_called_once_with()
         self.volume_manager.toplevel_mount.umount.assert_called_once_with()