[Ocfs2-devel] [patch]o2net: fix qs_holds may could not be zero

[Zhangyang]

Hi all
In our test, We fond that , when the network down, qs->qs_holds may could not be reduce to zero, lead to the node can't do fence.
o2net_idle_timer -> o2quo_conn_err -> qs->qs_holds++, after O2NET_QUORUM_DELAY_MS if qs_holds could be subtract to zero, it could do make_decision.
But if there are many nodes, when one node network down which contains o2net connections may not do o2net_idle_timer at the same time, so when a o2net_node have done nn->nn_still_up, but the qs_holds is not be zero, because other o2net_node have not done nn->nn_still_up.so the first o2net_node will do o2net_idle_timer again, and the qs_holds could be add again. And the qs_holds is global variable, so it formed a loop, the node could not do o2quo_make_decision, because of qs_holds never be zero.

I alter two functions o2quo_conn_up and o2quo_conn_err, take o2quo_set_hold or o2quo_clear_hold under control of the bit map qs_conn_bm


Best Regards,
Yang Zhang


@@ -280,20 +280,24 @@ void o2quo_conn_up(u8 node)
       struct o2quo_state *qs = &o2quo_state;
        spin_lock(&qs->qs_lock);
-
-        qs->qs_connected++;
-        mlog_bug_on_msg(qs->qs_connected == O2NM_MAX_NODES,
-                         "node %u\n", node);
-        mlog_bug_on_msg(test_bit(node, qs->qs_conn_bm), "node %u\n", node);
-        set_bit(node, qs->qs_conn_bm);
-
-        mlog(0, "node %u, %d total\n", node, qs->qs_connected);
-
-        if (!test_bit(node, qs->qs_hb_bm))
-                 o2quo_set_hold(qs, node);
-        else
-                 o2quo_clear_hold(qs, node);
-
+       if (!test_bit(node, qs->qs_conn_bm)) {
+                qs->qs_connected++;
+                mlog_bug_on_msg(qs->qs_connected == O2NM_MAX_NODES,
+                            "node %u\n", node);
+                mlog_bug_on_msg(test_bit(node, qs->qs_conn_bm), "node %u\n", node);
+                set_bit(node, qs->qs_conn_bm);
+
+                mlog(0, "node %u, %d total\n", node, qs->qs_connected);
+
+                if (!test_bit(node, qs->qs_hb_bm))
+                          o2quo_set_hold(qs, node);
+                else
+                          o2quo_clear_hold(qs, node);
+       }
       spin_unlock(&qs->qs_lock);
}
@@ -314,13 +318,13 @@ void o2quo_conn_err(u8 node)
                                   node, qs->qs_connected);
                 clear_bit(node, qs->qs_conn_bm);
+
+                if (test_bit(node, qs->qs_hb_bm))
+                          o2quo_set_hold(qs, node);
       }
        mlog(0, "node %u, %d total\n", node, qs->qs_connected);
-        if (test_bit(node, qs->qs_hb_bm))
-                 o2quo_set_hold(qs, node);
-
       spin_unlock(&qs->qs_lock);
}
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