diff -r ac449729a896 -r aa2a95dc6093 backup.py
--- a/backup.py	Sun Jan 21 22:46:05 2018 +0000
+++ b/backup.py	Sun Jan 21 23:52:35 2018 +0000
@@ -13,6 +13,17 @@
 
 logger=borgend.logger.getChild(__name__)
 
+# State
+INACTIVE=0
+SCHEDULED=1
+ACTIVE=2
+BUSY=3
+OFFLINE=4
+ERRORS=5
+
+def combine_state(state1, state2):
+    return max(state1, state2)
+
 loglevel_translation={
     'CRITICAL': logging.CRITICAL,
     'ERROR': logging.ERROR,
@@ -111,7 +122,6 @@
 
         self.config=config
         self.lastrun_when=None
-        self.lastrun_errors=None
         self.borg_instance=None
         self.current_operation=None
         self.thread_log=None
@@ -120,6 +130,7 @@
         self.scheduled_operation=None
         self.lock=Lock()
         self.__status_update_callback=None
+        self.state=INACTIVE
 
     def is_running(self):
         with self.lock:
@@ -185,8 +196,14 @@
                 logger.log(lvl, status['name'] + ': ' + status['message'])
                 if lvl>=logging.WARNING:
                     errors_this_message=status
+                    state=ERRORS
+                    if ('msgid' in status and
+                        (status['msgid']=='LockTimeout' or # observed in reality
+                         status['msgid']=='LockErrorT' or # in docs
+                         status['msgid']=='LockErrorT')): # in docs
+                        state=BUSY
                     with self.lock:
-                        self.current_operation['errors']=True
+                        self.state=combine_state(self.state, state)
                         status, callback=self.__status_unlocked()
             else:
                 logger.debug('Unrecognised log entry %s' % str(status))
@@ -210,30 +227,39 @@
 
         res=self.borg_instance.read_result()
 
-        errors=False
+        # Finish processing remaining errors
+        self.thread_log.join()
+
+        with self.lock:
+            state=self.state
+
+        # If there were no errors, reset back to INACTIVE state
+        if state==ACTIVE:
+            state=INACTIVE
 
         logger.debug('Borg result: %s' % str(res))
 
-        if res is None:
-            errors=True
+        if res is None and state==INACTIVE:
+            logger.error('No result from borg despite no error in log')
+            state=ERRORS
 
         logger.debug('Waiting for borg subprocess to terminate in result thread')
 
-        errors=errors or not self.borg_instance.wait()
+        if not self.borg_instance.wait():
+            logger.critical('Borg subprocess did not terminate')
+            state=combine_state(state, ERRORS)
 
-        logger.debug('Borg subprocess terminated (errors: %s); terminating result listener thread' % str(errors))
-
-        self.thread_log.join()
+        logger.debug('Borg subprocess terminated (end state %s); terminating result listener thread' % str(state))
 
         with self.lock:
             if self.current_operation['operation']=='create':
                 self.lastrun_when=self.current_operation['when_monotonic']
-                self.lastrun_errors=errors
             self.thread_res=None
             self.thread_log=None
             self.borg_instance=None
             self.current_operation=None
             self.__schedule_unlocked()
+            self.state=state
             status, callback=self.__status_unlocked()
         if callback:
             callback(self, status)
@@ -258,6 +284,7 @@
         self.queue=queue
         self.current_operation=op
         self.current_operation['when_monotonic']=time.monotonic()
+        self.state=ACTIVE
 
         t_log.start()
         t_res.start()
@@ -294,7 +321,7 @@
             except Exception as err:
                 logger.debug('Rescheduling after failure')
                 self.lastrun_when=time.monotonic()
-                self.lastrun_errors=True
+                self.state=ERRORS
                 self.__schedule_unlocked()
                 raise err
 
@@ -369,7 +396,7 @@
                 return {'operation': 'create',
                         'detail': 'initial',
                         'when_monotonic': now+initial_interval}
-        elif self.lastrun_errors:
+        elif self.state>=BUSY:
             if self.retry_interval==0:
                 return None
             else:
@@ -398,6 +425,7 @@
                 tmr=Timer(delay, self.__queue_timed_operation)
                 self.scheduled_operation=op
                 self.timer=tmr
+                self.state=combine_state(self.state, SCHEDULED)
                 tmr.start()
 
             return op
@@ -425,17 +453,12 @@
             else:
                 status={'type': 'nothing'}
 
-            if self.lastrun_errors is not None:
-                status['errors']=self.lastrun_errors
+        status['name']=self.name
+        status['state']=self.state
 
         if 'detail' not in status:
             status['detail']='NONE'
 
-        if 'errors' not in status:
-            status['errors']=False
-
-        status['name']=self.name
-
         if 'when_monotonic' in status:
             status['when']=(status['when_monotonic']
                             -time.monotonic()+time.time())