From b7794b4580bad7ab12e8b280bdc02885eeb04c9f Mon Sep 17 00:00:00 2001
From: Patrick Caulfield <pcaulfie@redhat.com>
Date: Apr 19 2006 08:01:11 +0000
Subject: Don't try to delete AUTODELETE barriers in timer context as we can't get

the semaphore that protects the structures.
bz#177577

---

diff --git a/cman-kernel/src/cnxman-private.h b/cman-kernel/src/cnxman-private.h
index ef75852..1e28f21 100644
--- a/cman-kernel/src/cnxman-private.h
+++ b/cman-kernel/src/cnxman-private.h
@@ -340,7 +340,7 @@ struct cl_barrier {
 	char name[MAX_BARRIER_NAME_LEN];
 	unsigned int flags;
 	enum { BARRIER_STATE_WAITING, BARRIER_STATE_INACTIVE,
-		    BARRIER_STATE_COMPLETE } state;
+	       BARRIER_STATE_COMPLETE, BARRIER_STATE_DELETED } state;
 	unsigned int expected_nodes;
 	unsigned int registered_nodes;
 	atomic_t     got_nodes;
diff --git a/cman-kernel/src/cnxman.c b/cman-kernel/src/cnxman.c
index 2cbff0e..31770f9 100644
--- a/cman-kernel/src/cnxman.c
+++ b/cman-kernel/src/cnxman.c
@@ -50,6 +50,7 @@ static void post_close_oob(unsigned char port, int nodeid);
 static void process_barrier_msg(struct cl_barriermsg *msg,
 				struct cluster_node *node);
 static struct cl_barrier *find_barrier(char *name);
+static void tidy_barriers(void);
 static void node_shutdown(void);
 static void node_cleanup(void);
 static int send_or_queue_message(struct socket *sock, void *buf, int len, struct sockaddr_cl *caddr,
@@ -160,6 +161,7 @@ static unsigned long mainloop_flags;
 
 #define ACK_TIMEOUT   1
 #define RESEND_NEEDED 2
+#define TIDY_BARRIERS 3
 
 /* A queue of messages waiting to be sent. If kcl_sendmsg is called outside of
  * process context then the messages get put in here */
@@ -370,6 +372,10 @@ static int cluster_kthread(void *unused)
 			check_for_unacked_nodes();
 		}
 
+		if (test_and_clear_bit(TIDY_BARRIERS, &mainloop_flags)) {
+			tidy_barriers();
+		}
+
 		/* Resend any unacked messages */
 		if (test_and_clear_bit(RESEND_NEEDED, &mainloop_flags)
 		    && acks_expected) {
@@ -3160,6 +3166,24 @@ static struct cl_barrier *find_barrier(char *name)
 	return NULL;
 }
 
+static void tidy_barriers(void)
+{
+	struct list_head *blist, *tmp;
+	struct cl_barrier *bar;
+
+	down(&barrier_list_lock);
+	list_for_each_safe(blist, tmp, &barrier_list) {
+		bar = list_entry(blist, struct cl_barrier, list);
+
+		if (bar->state == BARRIER_STATE_DELETED) {
+			P_BARRIER("Deleting barrier %s\n", bar->name);
+			list_del(&bar->list);
+			kfree(bar);
+		}
+	}
+	up(&barrier_list_lock);
+}
+
 /* Do the stuff we need to do when the barrier has completed phase 1 */
 static void check_barrier_complete_phase1(struct cl_barrier *barrier)
 {
@@ -3212,11 +3236,14 @@ static int check_barrier_complete_phase2(struct cl_barrier *barrier, int status)
 				barrier->callback(barrier->name, 0);
 				barrier->callback = NULL;
 			}
-			/* Remove it if it's AUTO-DELETE */
+			/* Flag it to be removed it if it's AUTO-DELETE.
+			   We can't actually remove it because we can't get the barrier semaphore
+			   in timer context */
 			if (barrier->flags & BARRIER_ATTR_AUTODELETE) {
-				list_del(&barrier->list);
+				barrier->state = BARRIER_STATE_DELETED;
+				set_bit(TIDY_BARRIERS, &mainloop_flags);
+				wake_up_interruptible(&cnxman_waitq);
 				spin_unlock_irq(&barrier->phase2_spinlock);
-				kfree(barrier);
 				return 1;
 			}
 		}