ocfs2/cluster: Maintain bitmap of quorum regions

o2hb allows online adding of regions. However, a newly added region is not
used in quorum calculations unless it has been added on all nodes. This patch
tracks a bitmap of such quorum regions.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 2a7cd17e96f0..62a8af271344 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -66,9 +66,12 @@ static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  * In global heartbeat, we maintain a series of region bitmaps.
  *      - o2hb_region_bitmap allows us to limit the region number to max region.
  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
+ *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
+ *              heartbeat on it.
  */
 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
+static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
 
 #define O2HB_DB_TYPE_LIVENODES          0
 struct o2hb_debug_buf {
@@ -607,6 +610,35 @@ static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
         o2nm_node_put(node);
 }
 
+static void o2hb_set_quorum_device(struct o2hb_region *reg,
+                                   struct o2hb_disk_slot *slot)
+{
+        assert_spin_locked(&o2hb_live_lock);
+
+        if (!o2hb_global_heartbeat_active())
+                return;
+
+        if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
+                return;
+
+        /*
+         * A region can be added to the quorum only when it sees all
+         * live nodes heartbeat on it. In other words, the region has been
+         * added to all nodes.
+         */
+        if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
+                   sizeof(o2hb_live_node_bitmap)))
+                return;
+
+        if (slot->ds_changed_samples < O2HB_LIVE_THRESHOLD)
+                return;
+
+        printk(KERN_NOTICE "o2hb: Region %s is now a quorum device\n",
+               config_item_name(&reg->hr_item));
+
+        set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
+}
+
 static int o2hb_check_slot(struct o2hb_region *reg,
                            struct o2hb_disk_slot *slot)
 {
@@ -772,6 +804,8 @@ fire_callbacks:
                 slot->ds_equal_samples = 0;
         }
 out:
+        o2hb_set_quorum_device(reg, slot);
+
         spin_unlock(&o2hb_live_lock);
 
         o2hb_run_event_list(&event);
@@ -1138,6 +1172,7 @@ int o2hb_init(void)
         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
+        memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
 
         return o2hb_debug_init();
 }