backups: Unmount repositories before and after backup

[sunil: Make the umount code specific to SSH repositories]
Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/backups/repository.py

@@ -133,6 +133,10 @@ class BaseBorgRepository(abc.ABC):
     def prepare():
         """Prepare the repository for operations."""
 
+    @staticmethod
+    def cleanup():
+        """Cleanup the repository after operations."""
+
     def get_info(self):
         """Return Borg information about a repository."""
         output = self.run(['info', '--path', self.borg_path])
@@ -393,8 +397,13 @@ class SshBorgRepository(BaseBorgRepository):
         if not self.is_usable():
             raise errors.SshfsError('Remote host not verified')
 
+        self._umount_ignore_errors()  # In case the connection is stale.
         self.mount()
 
+    def cleanup(self):
+        """Cleanup the repository after operations by unmounting."""
+        self._umount_ignore_errors()
+
     @property
     def hostname(self):
         """Return hostname from the remote path."""
@@ -440,6 +449,13 @@ class SshBorgRepository(BaseBorgRepository):
 
         self._run('sshfs', ['umount', '--mountpoint', self._mountpoint])
 
+    def _umount_ignore_errors(self):
+        """Run unmount operation and ignore any exceptions thrown."""
+        try:
+            self.umount()
+        except Exception as exception:
+            logger.warning('Unable to unmount repository', exc_info=exception)
+
     def remove(self):
         """Remove a repository from the kvstore and delete its mountpoint"""
         self.umount()

plinth/modules/backups/schedule.py

@@ -321,3 +321,5 @@ class Schedule:
                 logger.info('Cleaning up in repository %s backup archive %s',
                             self.repository_uuid, archive['name'])
                 repository.delete_archive(archive['name'])
+
+        repository.cleanup()