Merge pull request #1087 from mulkieran/issue_stratis-cli_1085

Support snapshot revert operations

docs/stratis.txt

@@ -142,6 +142,11 @@ filesystem set-size-limit <pool_name> <fs_name> <size_limit>::
            as the filesystem's current size, use the keyword "current".
 filesystem unset-size-limit <pool_name> <fs_name>::
            Remove a filesystem size limit previously set.
+filesystem schedule-revert <pool_name> <snapshot_name>::
+     Set a flag so that when the pool is next started, the specified snapshot
+     will overwrite its origin filesystem.
+filesystem cancel-revert <pool_name> <snapshot_name>::
+     Cancel a scheduled revert.
 filesystem debug get-object-path <(--uuid <uuid> |--name <name>)> ::
      Look up the D-Bus object path for a filesystem given the UUID or name.
 filesystem debug get-metadata <pool_name> [--pretty] [--written] [--fs-name <fs-name>] ::
@@ -381,7 +386,9 @@ Created::
 	The time the filesystem was created.
 
 Snapshot origin::
-	If this filesystem is a snapshot, its origin.
+	If this filesystem is a snapshot, its origin. If the filesystem is
+	a snapshot, whether or not it is scheduled to replace its origin
+	next time the pool is started.
 
 Sizes::
 	The logical size of the Stratis filesystem, the total space actually

src/stratis_cli/_actions/_introspect.py

@@ -124,6 +124,7 @@
     <property name="Devnode" type="s" access="read">
       <annotation name="org.freedesktop.DBus.Property.EmitsChangedSignal" value="invalidates" />
     </property>
+    <property name="MergeScheduled" type="b" access="readwrite" />
     <property name="Name" type="s" access="read" />
     <property name="Origin" type="(bs)" access="read" />
     <property name="Pool" type="o" access="read">

src/stratis_cli/_actions/_list_filesystem.py

@@ -176,7 +176,7 @@ def display(self):
             date_parser.parse(fs.Created()).astimezone().strftime("%b %d %Y %H:%M")
         )
 
-        origin = get_property(fs.Origin(), self.uuid_formatter, "None")
+        origin = get_property(fs.Origin(), self.uuid_formatter, None)
 
         print(f"UUID: {self.uuid_formatter(fs.Uuid())}")
         print(f"Name: {fs.Name()}")
@@ -186,7 +186,10 @@ def display(self):
         print()
         print(f"Created: {created}")
         print()
-        print(f"Snapshot origin: {origin}")
+        print(f'Snapshot origin: {"None" if origin is None else origin}')
+        if origin is not None:
+            scheduled = "Yes" if fs.MergeScheduled() else "No"
+            print(f"    Revert scheduled: {scheduled}")
         print()
         print("Sizes:")
         print(f"  Logical size of thin device: {total}")

src/stratis_cli/_actions/_logical.py

@@ -21,6 +21,7 @@
 from .._constants import Id, IdType
 from .._errors import (
     StratisCliEngineError,
+    StratisCliFsMergeScheduledChangeError,
     StratisCliFsSizeLimitChangeError,
     StratisCliIncoherenceError,
     StratisCliNoChangeError,
@@ -336,3 +337,64 @@ def unset_size_limit(namespace):
             raise StratisCliFsSizeLimitChangeError(None)
 
         Filesystem.Properties.SizeLimit.Set(get_object(fs_object_path), (False, ""))
+
+    @staticmethod
+    def schedule_revert(namespace):
+        """
+        Schedule reverting a snapshot into its origin.
+        """
+        # pylint: disable=import-outside-toplevel
+        from ._data import Filesystem, MOFilesystem, ObjectManager, filesystems, pools
+
+        proxy = get_object(TOP_OBJECT)
+        managed_objects = ObjectManager.Methods.GetManagedObjects(proxy, {})
+        (pool_object_path, _) = next(
+            pools(props={"Name": namespace.pool_name})
+            .require_unique_match(True)
+            .search(managed_objects)
+        )
+        (fs_object_path, fs_info) = next(
+            filesystems(
+                props={"Name": namespace.snapshot_name, "Pool": pool_object_path}
+            )
+            .require_unique_match(True)
+            .search(managed_objects)
+        )
+
+        merge_requested = MOFilesystem(fs_info).MergeScheduled()
+
+        if bool(merge_requested):
+            raise StratisCliFsMergeScheduledChangeError(True)
+
+        Filesystem.Properties.MergeScheduled.Set(get_object(fs_object_path), True)
+
+    @staticmethod
+    def cancel_revert(namespace):
+        """
+        Cancel reverting a snapshot into its origin.
+        """
+        # pylint: disable=import-outside-toplevel
+        from ._data import Filesystem, MOFilesystem, ObjectManager, filesystems, pools
+
+        proxy = get_object(TOP_OBJECT)
+        managed_objects = ObjectManager.Methods.GetManagedObjects(proxy, {})
+        (pool_object_path, _) = next(
+            pools(props={"Name": namespace.pool_name})
+            .require_unique_match(True)
+            .search(managed_objects)
+        )
+        (fs_object_path, fs_info) = next(
+            filesystems(
+                props={"Name": namespace.snapshot_name, "Pool": pool_object_path}
+            )
+            .require_unique_match(True)
+            .search(managed_objects)
+        )
+
+        mofs = MOFilesystem(fs_info)
+        (merge_requested, (origin_set, _)) = (mofs.MergeScheduled(), mofs.Origin())
+
+        if origin_set and not bool(merge_requested):
+            raise StratisCliFsMergeScheduledChangeError(False)
+
+        Filesystem.Properties.MergeScheduled.Set(get_object(fs_object_path), False)

src/stratis_cli/_errors.py

@@ -103,6 +103,18 @@ def __str__(self):
         return f"Filesystem's size limit is exactly {self.value}"
 
 
+class StratisCliFsMergeScheduledChangeError(StratisCliNoPropertyChangeError):
+    """
+    Raised when the user requests the same filesystems MergeScheduled value
+    that the filesystem already has.
+    """
+
+    def __str__(self):
+        if self.value:
+            return "Filesystem is already scheduled for a revert operation."
+        return "Filesystem is not currently scheduled for a revert operation."
+
+
 class StratisCliHasCacheChangeError(StratisCliNoPropertyChangeError):
     """
     Raised when the user request cache initialization, but a cache is already

src/stratis_cli/_parser/_logical.py

@@ -235,6 +235,51 @@ def verify(self, namespace, parser):
             "func": LogicalActions.unset_size_limit,
         },
     ),
+    (
+        "schedule-revert",
+        {
+            "help": (
+                "Schedule a revert operation for this snapshot filesystem "
+                "into its origin filesystem"
+            ),
+            "args": [
+                (
+                    "pool_name",
+                    {
+                        "help": (
+                            "Name of the pool the snapshot and its origin belong to"
+                        ),
+                    },
+                ),
+                (
+                    "snapshot_name",
+                    {"help": "Name of the snapshot filesystem"},
+                ),
+            ],
+            "func": LogicalActions.schedule_revert,
+        },
+    ),
+    (
+        "cancel-revert",
+        {
+            "help": "Cancel a previously scheduled revert operation",
+            "args": [
+                (
+                    "pool_name",
+                    {
+                        "help": (
+                            "Name of the pool the snapshot and its origin belong to"
+                        ),
+                    },
+                ),
+                (
+                    "snapshot_name",
+                    {"help": "Name of the snapshot filesystem"},
+                ),
+            ],
+            "func": LogicalActions.cancel_revert,
+        },
+    ),
     (
         "debug",
         {

tests/whitebox/integration/logical/test_cancel_revert.py

@@ -0,0 +1,94 @@
+# Copyright 2023 Red Hat, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Test 'cancel-revert'.
+"""
+
+# isort: FIRSTPARTY
+from dbus_python_client_gen import DPClientInvocationError
+
+# isort: LOCAL
+from stratis_cli import StratisCliErrorCodes
+from stratis_cli._errors import StratisCliFsMergeScheduledChangeError
+
+from .._misc import RUNNER, SimTestCase, device_name_list
+
+_DEVICE_STRATEGY = device_name_list(1)
+_ERROR = StratisCliErrorCodes.ERROR
+
+
+class FsCancelRevertTestCase(SimTestCase):
+    """
+    Test canceling a filesystem revert.
+    """
+
+    _MENU = ["--propagate", "filesystem", "cancel-revert"]
+    _POOLNAME = "pool"
+    _FSNAME = "nofs"
+    _SNAPNAME = "snofs"
+
+    def setUp(self):
+        """
+        Start the stratisd daemon with the simulator.
+        """
+        super().setUp()
+        command_line = ["pool", "create", self._POOLNAME] + _DEVICE_STRATEGY()
+        RUNNER(command_line)
+
+        command_line = [
+            "filesystem",
+            "create",
+            self._POOLNAME,
+            self._FSNAME,
+        ]
+        RUNNER(command_line)
+
+        command_line = [
+            "filesystem",
+            "snapshot",
+            self._POOLNAME,
+            self._FSNAME,
+            self._SNAPNAME,
+        ]
+        RUNNER(command_line)
+
+    def test_cancel_revert_when_unscheduled(self):
+        """
+        Cancelling an unscheduled revert should fail.
+        """
+        command_line = self._MENU + [self._POOLNAME, self._SNAPNAME]
+        self.check_error(StratisCliFsMergeScheduledChangeError, command_line, _ERROR)
+
+    def test_cancel_revert_when_no_origin(self):
+        """
+        Cancelling a revert on a filesystem with no origin should fail.
+        """
+        command_line = self._MENU + [self._POOLNAME, self._FSNAME]
+        self.check_error(DPClientInvocationError, command_line, _ERROR)
+
+    def test_cancel_a_revert_twice(self):
+        """
+        Cancelling a revert twice should fail.
+        """
+        command_line = [
+            "--propagate",
+            "filesystem",
+            "schedule-revert",
+            self._POOLNAME,
+            self._SNAPNAME,
+        ]
+        RUNNER(command_line)
+        command_line = self._MENU + [self._POOLNAME, self._SNAPNAME]
+        RUNNER(command_line)
+        self.check_error(StratisCliFsMergeScheduledChangeError, command_line, _ERROR)

tests/whitebox/integration/logical/test_list.py

@@ -144,6 +144,14 @@ def setUp(self):
         RUNNER(command_line)
         command_line = ["filesystem", "create", self._POOLNAMES[0], self._VOLUMES[1]]
         RUNNER(command_line)
+        command_line = [
+            "filesystem",
+            "snapshot",
+            self._POOLNAMES[0],
+            self._VOLUMES[1],
+            self._VOLUMES[2],
+        ]
+        RUNNER(command_line)
         command_line = ["pool", "create", self._POOLNAMES[1]] + device_lists[1]
         RUNNER(command_line)
         command_line = ["filesystem", "create", self._POOLNAMES[1], self._VOLUMES[2]]
@@ -191,3 +199,10 @@ def test_list_fs_name_pool_name_not_match(self):
         self.check_error(
             DbusClientUniqueResultError, command_line, StratisCliErrorCodes.ERROR
         )
+
+    def test_list_fs_name_snapshot(self):
+        """
+        Test list detailed view of a snapshot to test printing of revert information.
+        """
+        command_line = self._MENU + [self._POOLNAMES[0], f"--name={self._VOLUMES[2]}"]
+        TEST_RUNNER(command_line)