From 5ae585ce1386da509fbd9dac6f1abdff1bc0984c Mon Sep 17 00:00:00 2001
From: Mike Degatano <michael.degatano@gmail.com>
Date: Tue, 12 Sep 2023 18:56:24 -0400
Subject: [PATCH] Unmount mounts before backup restore (#4557)

---
 supervisor/backups/backup.py  | 21 ++++++++++++++-
 tests/backups/test_manager.py | 51 +++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/supervisor/backups/backup.py b/supervisor/backups/backup.py
index 6fad87a825f..95320cd2188 100644
--- a/supervisor/backups/backup.py
+++ b/supervisor/backups/backup.py
@@ -1,4 +1,5 @@
 """Representation of a backup file."""
+import asyncio
 from base64 import b64decode, b64encode
 from collections.abc import Awaitable
 from datetime import timedelta
@@ -490,6 +491,18 @@ async def _folder_restore(name: str) -> None:
                 _LOGGER.warning("Can't find restore folder %s", name)
                 return
 
+            # Unmount any mounts within folder
+            bind_mounts = [
+                bound.bind_mount
+                for bound in self.sys_mounts.bound_mounts
+                if bound.bind_mount.local_where
+                and bound.bind_mount.local_where.is_relative_to(origin_dir)
+            ]
+            if bind_mounts:
+                await asyncio.gather(
+                    *[bind_mount.unmount() for bind_mount in bind_mounts]
+                )
+
             # Clean old stuff
             if origin_dir.is_dir():
                 await remove_folder(origin_dir, content_only=True)
@@ -510,7 +523,13 @@ def _restore() -> None:
                 except (tarfile.TarError, OSError) as err:
                     _LOGGER.warning("Can't restore folder %s: %s", name, err)
 
-            await self.sys_run_in_executor(_restore)
+            try:
+                await self.sys_run_in_executor(_restore)
+            finally:
+                if bind_mounts:
+                    await asyncio.gather(
+                        *[bind_mount.mount() for bind_mount in bind_mounts]
+                    )
 
         # Restore folder sequential
         # avoid issue on slow IO
diff --git a/tests/backups/test_manager.py b/tests/backups/test_manager.py
index d38e8a46566..698f355748d 100644
--- a/tests/backups/test_manager.py
+++ b/tests/backups/test_manager.py
@@ -433,6 +433,57 @@ async def test_backup_media_with_mounts(
     assert not mount_dir.exists()
 
 
+async def test_backup_media_with_mounts_retains_files(
+    coresys: CoreSys,
+    all_dbus_services: dict[str, DBusServiceMock],
+    tmp_supervisor_data,
+    path_extern,
+    mount_propagation,
+):
+    """Test backing up media folder with mounts retains mount files."""
+    systemd_service: SystemdService = all_dbus_services["systemd"]
+    systemd_service.response_get_unit = [
+        DBusError("org.freedesktop.systemd1.NoSuchUnit", "error"),
+        "/org/freedesktop/systemd1/unit/tmp_2dyellow_2emount",
+        DBusError("org.freedesktop.systemd1.NoSuchUnit", "error"),
+        "/org/freedesktop/systemd1/unit/tmp_2dyellow_2emount",
+        "/org/freedesktop/systemd1/unit/tmp_2dyellow_2emount",
+        "/org/freedesktop/systemd1/unit/tmp_2dyellow_2emount",
+    ]
+
+    # Add a media mount
+    await coresys.mounts.load()
+    await coresys.mounts.create_mount(
+        Mount.from_dict(
+            coresys,
+            {
+                "name": "media_test",
+                "usage": "media",
+                "type": "cifs",
+                "server": "test.local",
+                "share": "test",
+            },
+        )
+    )
+
+    # Make a partial backup
+    coresys.core.state = CoreState.RUNNING
+    coresys.hardware.disk.get_disk_free_space = lambda x: 5000
+    backup: Backup = await coresys.backups.do_backup_partial("test", folders=["media"])
+
+    systemd_service.StopUnit.calls.clear()
+    systemd_service.StartTransientUnit.calls.clear()
+    with patch.object(DockerHomeAssistant, "is_running", return_value=True):
+        await coresys.backups.do_restore_partial(backup, folders=["media"])
+
+    assert systemd_service.StopUnit.calls == [
+        ("mnt-data-supervisor-media-media_test.mount", "fail")
+    ]
+    assert systemd_service.StartTransientUnit.calls == [
+        ("mnt-data-supervisor-media-media_test.mount", "fail", ANY, [])
+    ]
+
+
 async def test_backup_share_with_mounts(
     coresys: CoreSys,
     all_dbus_services: dict[str, DBusServiceMock],