Add parent attribute to volume setup

For the btrfs volume management, allow to put a volume into a specific
parent volume. If not specified the volume is below the default volume
This Fixes #2316

kiwi/mount_manager.py

@@ -19,7 +19,9 @@
 import time
 import logging
 from textwrap import dedent
-from typing import List
+from typing import (
+    List, Dict
+)
 
 # project
 from kiwi.path import Path
@@ -41,9 +43,14 @@ class MountManager:
 
     * :param string device: device node name
     * :param string mountpoint: mountpoint directory name
+    * :param dict attributes: optional attributes to store
     """
-    def __init__(self, device: str, mountpoint: str = ''):
+    def __init__(
+        self, device: str, mountpoint: str = '',
+        attributes: Dict[str, str] = {}
+    ):
         self.device = device
+        self.attributes = attributes
         if not mountpoint:
             self.mountpoint_tempdir = Temporary(
                 prefix='kiwi_mount_manager.'
@@ -53,6 +60,12 @@ def __init__(self, device: str, mountpoint: str = ''):
             Path.create(mountpoint)
             self.mountpoint = mountpoint
 
+    def get_attributes(self) -> Dict[str, str]:
+        """
+        Return attributes dict for this mount manager
+        """
+        return self.attributes
+
     def bind_mount(self) -> None:
         """
         Bind mount the device to the mountpoint

kiwi/schema/kiwi.rnc

@@ -2564,6 +2564,13 @@ div {
         ## not specified the name specifies a path which has to
         ## exist inside the root directory.
         attribute name { text }
+    k.volume.parent.attribute =
+        ## The name/path of the parent volume.
+        ## Evaluated only for the btrfs volume manager to allow
+        ## specifying the parent subvolume to nest this volume in.
+        ## If not specified the parent is always the volume set
+        ## as the default volume
+        attribute parent { text }
     k.volume.mountpoint.attribute =
         ## volume path. The mountpoint specifies a path which has to
         ## exist inside the root directory.
@@ -2596,6 +2603,7 @@ div {
         k.volume.mountpoint.attribute? &
         k.volume.label.attribute? &
         k.volume.name.attribute &
+        k.volume.parent.attribute? &
         k.volume.size.attribute?
     k.volume =
         ## Specify which parts of the filesystem should be

kiwi/schema/kiwi.rng

@@ -3851,6 +3851,15 @@ not specified the name specifies a path which has to
 exist inside the root directory.</a:documentation>
       </attribute>
     </define>
+    <define name="k.volume.parent.attribute">
+      <attribute name="parent">
+        <a:documentation>The name/path of the parent volume.
+Evaluated only for the btrfs volume manager to allow
+specifying the parent subvolume to nest this volume in.
+If not specified the parent is always the volume set
+as the default volume</a:documentation>
+      </attribute>
+    </define>
     <define name="k.volume.mountpoint.attribute">
       <attribute name="mountpoint">
         <a:documentation>volume path. The mountpoint specifies a path which has to
@@ -3907,6 +3916,9 @@ The latter is the default.</a:documentation>
           <ref name="k.volume.label.attribute"/>
         </optional>
         <ref name="k.volume.name.attribute"/>
+        <optional>
+          <ref name="k.volume.parent.attribute"/>
+        </optional>
         <optional>
           <ref name="k.volume.size.attribute"/>
         </optional>

kiwi/volume_manager/btrfs.py

@@ -92,7 +92,6 @@ def post_init(self, custom_args):
 
         self.subvol_mount_list = []
         self.toplevel_mount = None
-        self.toplevel_volume = None
 
     def setup(self, name=None):
         """
@@ -154,6 +153,7 @@ def setup(self, name=None):
             # Mount /{some-name}/.snapshots as /.snapshots inside the root
             snapshots_mount = MountManager(
                 device=self.device,
+                attributes={'subvol': f'{self.root_volume_name}/.snapshots'},
                 mountpoint=snapshot + '/.snapshots'
             )
             self.subvol_mount_list.append(snapshots_mount)
@@ -191,6 +191,9 @@ def create_volumes(self, filesystem_name):
             else:
                 log.info('--> sub volume %s', volume.realpath)
                 toplevel = self.mountpoint + f'/{self.root_volume_name}/'
+                if volume.parent:
+                    toplevel = self.mountpoint + '/' + volume.parent
+
                 volume_parent_path = os.path.normpath(
                     toplevel + os.path.dirname(volume.realpath)
                 )
@@ -207,12 +210,19 @@ def create_volumes(self, filesystem_name):
                 )
                 volume_mountpoint = self.mountpoint + \
                     self.root_volume_name + '/'
+                attributes = {
+                    'parent': volume.parent or ''
+                }
                 if self.custom_args['root_is_snapshot']:
                     volume_mountpoint = self.mountpoint + \
                         f'/{self.root_volume_name}/.snapshots/1/snapshot/'
+                    attributes = {
+                        'subvol': f'{self.root_volume_name}{volume.realpath}'
+                    }
 
                 volume_mount = MountManager(
                     device=self.device,
+                    attributes=attributes,
                     mountpoint=os.path.normpath(
                         volume_mountpoint + volume.realpath
                     )
@@ -245,12 +255,17 @@ def get_fstab(self, persistency_type='by-label', filesystem_name=None):
             fs_check = self._is_volume_enabled_for_fs_check(
                 volume_mount.mountpoint
             )
+            mount_point = volume_mount.mountpoint.replace(self.mountpoint, '')
+            if self.root_volume_name != '/':
+                mount_point = mount_point.replace(self.root_volume_name, '')
+
+            if self.custom_args['root_is_snapshot']:
+                mount_point = subvol_name.replace(self.root_volume_name, '')
+
             fstab_entry = ' '.join(
                 [
                     blkid_type + '=' + device_id,
-                    subvol_name.replace(
-                        self.root_volume_name, ''
-                    ) if self.root_volume_name != '/' else subvol_name,
+                    mount_point if mount_point.startswith(os.sep) else f'{os.sep}{mount_point}',
                     'btrfs', ','.join(mount_entry_options),
                     '0 {fs_passno}'.format(
                         fs_passno='2' if fs_check else '0'
@@ -295,8 +310,11 @@ def mount_volumes(self):
 
         for volume_mount in self.subvol_mount_list:
             if self.volumes_mounted_initially:
+                toplevel = self.root_volume_name
+                if self.custom_args['root_is_snapshot']:
+                    toplevel = f'{self.root_volume_name}/.snapshots/1/snapshot'
                 volume_mount.mountpoint = os.path.normpath(
-                    volume_mount.mountpoint.replace(self.toplevel_volume, '', 1)
+                    volume_mount.mountpoint.replace(toplevel, '', 1)
                 )
             if not os.path.exists(volume_mount.mountpoint):
                 Path.create(volume_mount.mountpoint)
@@ -432,7 +450,6 @@ def _set_default_volume(self, default_volume):
                             volume_id, self.mountpoint
                         ]
                     )
-                    self.toplevel_volume = default_volume
                     return
 
         raise KiwiVolumeRootIDError(
@@ -514,10 +531,16 @@ def _get_subvol_name_from_mountpoint(self, volume_mount):
         subvol_name = os.sep.join(
             volume_mount.mountpoint.split(os.sep)[path_start_index:]
         )
-        if self.toplevel_volume and self.toplevel_volume in subvol_name:
-            subvol_name = subvol_name.replace(self.toplevel_volume, '')
+        parent = self.root_volume_name
+        if volume_mount.get_attributes().get('parent'):
+            parent = volume_mount.attributes.get('parent')
+
+        if volume_mount.get_attributes().get('subvol'):
+            subvol_name = volume_mount.get_attributes().get('subvol')
+            parent = ''
+
         return os.path.normpath(
-            os.sep.join([self.root_volume_name, subvol_name]).replace('//', '/')
+            os.sep.join([parent, subvol_name]).replace('//', '/').lstrip(os.sep)
         )
 
     def __del__(self):

kiwi/xml_parse.py

@@ -4984,14 +4984,15 @@ class volume(GeneratedsSuper):
     """Specify which parts of the filesystem should be on an extra volume."""
     subclass = None
     superclass = None
-    def __init__(self, copy_on_write=None, filesystem_check=None, freespace=None, mountpoint=None, label=None, name=None, size=None):
+    def __init__(self, copy_on_write=None, filesystem_check=None, freespace=None, mountpoint=None, label=None, name=None, parent=None, size=None):
         self.original_tagname_ = None
         self.copy_on_write = _cast(bool, copy_on_write)
         self.filesystem_check = _cast(bool, filesystem_check)
         self.freespace = _cast(None, freespace)
         self.mountpoint = _cast(None, mountpoint)
         self.label = _cast(None, label)
         self.name = _cast(None, name)
+        self.parent = _cast(None, parent)
         self.size = _cast(None, size)
     def factory(*args_, **kwargs_):
         if CurrentSubclassModule_ is not None:
@@ -5016,6 +5017,8 @@ def get_label(self): return self.label
     def set_label(self, label): self.label = label
     def get_name(self): return self.name
     def set_name(self, name): self.name = name
+    def get_parent(self): return self.parent
+    def set_parent(self, parent): self.parent = parent
     def get_size(self): return self.size
     def set_size(self, size): self.size = size
     def validate_volume_size_type(self, value):
@@ -5071,6 +5074,9 @@ def exportAttributes(self, outfile, level, already_processed, namespaceprefix_='
         if self.name is not None and 'name' not in already_processed:
             already_processed.add('name')
             outfile.write(' name=%s' % (self.gds_encode(self.gds_format_string(quote_attrib(self.name), input_name='name')), ))
+        if self.parent is not None and 'parent' not in already_processed:
+            already_processed.add('parent')
+            outfile.write(' parent=%s' % (self.gds_encode(self.gds_format_string(quote_attrib(self.parent), input_name='parent')), ))
         if self.size is not None and 'size' not in already_processed:
             already_processed.add('size')
             outfile.write(' size=%s' % (quote_attrib(self.size), ))
@@ -5120,6 +5126,10 @@ def buildAttributes(self, node, attrs, already_processed):
         if value is not None and 'name' not in already_processed:
             already_processed.add('name')
             self.name = value
+        value = find_attr_value_('parent', node)
+        if value is not None and 'parent' not in already_processed:
+            already_processed.add('parent')
+            self.parent = value
         value = find_attr_value_('size', node)
         if value is not None and 'size' not in already_processed:
             already_processed.add('size')

kiwi/xml_state.py

@@ -67,6 +67,7 @@
 volume_type = NamedTuple(
     'volume_type', [
         ('name', str),
+        ('parent', str),
         ('size', str),
         ('realpath', str),
         ('mountpoint', Optional[str]),
@@ -1574,6 +1575,7 @@ def get_volumes(self) -> List[volume_type]:
                 [
                     volume_type(
                         name=volume_name,
+                        parent=volume_parent,
                         size=volume_size,
                         realpath=path,
                         mountpoint=path,
@@ -1600,6 +1602,7 @@ def get_volumes(self) -> List[volume_type]:
                 # volume setup for a full qualified volume with name and
                 # mountpoint information. See below for exceptions
                 name = volume.get_name()
+                parent = volume.get_parent() or ''
                 mountpoint = volume.get_mountpoint()
                 realpath = mountpoint
                 size = volume.get_size()
@@ -1667,6 +1670,7 @@ def get_volumes(self) -> List[volume_type]:
                 volume_type_list.append(
                     volume_type(
                         name=name,
+                        parent=parent,
                         size=size,
                         fullsize=fullsize,
                         mountpoint=mountpoint,
@@ -1694,6 +1698,7 @@ def get_volumes(self) -> List[volume_type]:
             volume_type_list.append(
                 volume_type(
                     name=root_volume_name,
+                    parent='',
                     size=size,
                     fullsize=fullsize,
                     mountpoint=None,
@@ -1708,6 +1713,7 @@ def get_volumes(self) -> List[volume_type]:
             volume_type_list.append(
                 volume_type(
                     name=swap_name,
+                    parent='',
                     size='size:{0}'.format(swap_mbytes),
                     fullsize=False,
                     mountpoint=None,

test/unit/mount_manager_test.py

@@ -25,6 +25,9 @@ def setup(self, mock_path_create):
     def setup_method(self, cls, mock_path_create):
         self.setup()
 
+    def test_get_attributes(self):
+        assert self.mount_manager.get_attributes() == {}
+
     @patch('kiwi.mount_manager.Temporary')
     def test_setup_empty_mountpoint(self, mock_Temporary):
         mock_Temporary.return_value.new_dir.return_value.name = 'tmpdir'