solved potential race condition and some cleanup

code review brought up some few places where we may have run into a race.
They have most probably been introduced during the recent set of changes. But
I do not look at older versions because of the changed architecture, one can
not simply backport this patch.

1 files changed, 11 insertions, 6 deletions

diff --git a/runtime/queue.c b/runtime/queue.c
index 7590af18..50bfaca9 100644
--- a/runtime/queue.c
+++ b/runtime/queue.c
@@ -264,6 +264,7 @@ static inline rsRetVal qqueueAdviseMaxWorkers(qqueue_t *pThis)
  * call this function. As such,it may validly be that DA is already shut down.
  * So we just check if we are in init phase and then wait for full startup.
  * If in non-DA mode, we silently return.
+ * IMPORTANT: the QUEUE MUTEX MUST BE LOOKED WHEN this funnction is called!
  * rgerhards, 2008-02-27
  */
 static rsRetVal
@@ -1167,12 +1168,12 @@ tryShutdownWorkersWithinQueueTimeout(qqueue_t *pThis)
 			wtpAdviseMaxWorkers(pThis->pWtpDA, 1);
 		}
 	}
-	d_pthread_mutex_unlock(pThis->mut);
 
 	/* at this stage, we need to have the DA worker properly initialized and running (if there is one) */
 	if(pThis->bRunsDA) {
 		qqueueWaitDAModeInitialized(pThis);
 	}
+	d_pthread_mutex_unlock(pThis->mut);
 
 	/* Now wait for the queue's workers to shut down. Note that we run into the code even if we just found
 	 * out there are no active workers - that doesn't matter: the wtp knows about that and so will
@@ -1200,7 +1201,9 @@ tryShutdownWorkersWithinQueueTimeout(qqueue_t *pThis)
 	}
 
 	/* OK, the worker for the regular queue is processed, on the the DA queue regular worker. */
+	d_pthread_mutex_lock(pThis->mut);
 	if(pThis->bRunsDA) {
+		d_pthread_mutex_unlock(pThis->mut);
 		dbgoprint((obj_t*) pThis, "we have a DA queue (0x%lx), requesting its shutdown.\n",
 			 qqueueGetID(pThis->pqDA));
 		/* we use the same absolute timeout as above, so we do not use more than the configured
@@ -1216,13 +1219,15 @@ tryShutdownWorkersWithinQueueTimeout(qqueue_t *pThis)
 		/* we also instruct the DA worker pool to shutdown ASAP. If we need it for persisting
 		 * the queue, it is restarted at a later stage. We don't care here if a timeout happens.
 		 */
-		dbgoprint((obj_t*) pThis, "trying shutdown of regular worker of DA queue\n");
+		dbgoprint((obj_t*) pThis, "trying shutdown of main queue DA worker pool\n");
 		iRetLocal = wtpShutdownAll(pThis->pWtpDA, wtpState_SHUTDOWN_IMMEDIATE, &tTimeout);
 		if(iRetLocal == RS_RET_TIMED_OUT) {
 			dbgoprint((obj_t*) pThis, "shutdown timed out on main queue DA worker pool (this is OK)\n");
 		} else {
 			dbgoprint((obj_t*) pThis, "main queue DA worker pool shut down.\n");
 		}
+	} else {
+		d_pthread_mutex_unlock(pThis->mut);
 	}
 
 	RETiRet;
@@ -1247,7 +1252,7 @@ tryShutdownWorkersWithinActionTimeout(qqueue_t *pThis)
 	ASSERT(pThis->pqParent == NULL); /* detect invalid calling sequence */
 
 	/* instruct workers to finish ASAP, even if still work exists */
-	/* note that we modify bEnqOnly direclty, because going through the method would
+	/* note that we modify bEnqOnly directly, because going through the method would
 	 * startup some workers again. So this is OK here. -- rgerhards, 2009-05-28
 	 */
 	pThis->bEnqOnly = 1;
@@ -2281,12 +2286,14 @@ DoSaveOnShutdown(qqueue_t *pThis)
 
 	ISOBJ_TYPE_assert(pThis, qqueue);
 
+	d_pthread_mutex_lock(pThis->mut);	/* some workers may be running in parallel! */
 dbgprintf("after InitDA, queue log %d, phys %d\n", getLogicalQueueSize(pThis), getPhysicalQueueSize(pThis));
 	if(pThis->bRunsDA != 2) {
-		InitDA(pThis, QUEUE_MODE_ENQONLY, LOCK_MUTEX); /* switch to DA mode */
+		InitDA(pThis, QUEUE_MODE_ENQONLY, MUTEX_ALREADY_LOCKED); /* switch to DA mode */
 dbgprintf("after InitDA, queue log %d, phys %d\n", getLogicalQueueSize(pThis), getPhysicalQueueSize(pThis));
 		qqueueWaitDAModeInitialized(pThis);	/* make sure DA mode is actually started, else we may have a race! */
 	}
+	d_pthread_mutex_unlock(pThis->mut);
 	/* make sure we do not timeout before we are done */
 	dbgoprint((obj_t*) pThis, "bSaveOnShutdown configured, infinite timeout set\n");
 	timeoutComp(&tTimeout, QUEUE_TIMEOUT_ETERNAL);
@@ -2321,9 +2328,7 @@ CODESTARTobjDestruct(qqueue)
 	 * we need to reset the logical dequeue pointer, persist the queue if configured to do
 	 * so and then destruct everything. -- rgerhards, 2009-05-26
 	 */
-dbgprintf("XXX: pre unDeq disk log %d, phys %d\n", getLogicalQueueSize(pThis), getPhysicalQueueSize(pThis));
 	CHKiRet(pThis->qUnDeqAll(pThis));
-dbgprintf("XXX: post unDeq disk log %d, phys %d\n", getLogicalQueueSize(pThis), getPhysicalQueueSize(pThis));
 
 	if(pThis->bIsDA && getPhysicalQueueSize(pThis) > 0 && pThis->bSaveOnShutdown) {
 		CHKiRet(DoSaveOnShutdown(pThis));