ocfs2/cluster: Add heartbeat mode configfs parameter

Add heartbeat mode parameter to the configfs tree. This will be used
to set/show the heartbeat mode. The user is free to toggle the mode
between local and global as long as there is no active heartbeat region.

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

1 files changed, 72 insertions, 0 deletions

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 41d5f1f92d56..4d36459a8343 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -77,7 +77,19 @@ static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 
 #define O2HB_DEFAULT_BLOCK_BITS       9
 
+enum o2hb_heartbeat_modes {
+        O2HB_HEARTBEAT_LOCAL            = 0,
+        O2HB_HEARTBEAT_GLOBAL,
+        O2HB_HEARTBEAT_NUM_MODES,
+};
+
+char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
+                "local",        /* O2HB_HEARTBEAT_LOCAL */
+                "global",       /* O2HB_HEARTBEAT_GLOBAL */
+};
+
 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
+unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 
 /* Only sets a new threshold if there are no active regions.
  *
@@ -94,6 +106,22 @@ static void o2hb_dead_threshold_set(unsigned int threshold)
         }
 }
 
+static int o2hb_global_hearbeat_mode_set(unsigned int hb_mode)
+{
+        int ret = -1;
+
+        if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
+                spin_lock(&o2hb_live_lock);
+                if (list_empty(&o2hb_all_regions)) {
+                        o2hb_heartbeat_mode = hb_mode;
+                        ret = 0;
+                }
+                spin_unlock(&o2hb_live_lock);
+        }
+
+        return ret;
+}
+
 struct o2hb_node_event {
         struct list_head        hn_item;
         enum o2hb_callback_type hn_event_type;
@@ -1688,6 +1716,41 @@ static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group
         return count;
 }
 
+static
+ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
+                                       char *page)
+{
+        return sprintf(page, "%s\n",
+                       o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
+}
+
+static
+ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
+                                        const char *page, size_t count)
+{
+        unsigned int i;
+        int ret;
+        size_t len;
+
+        len = (page[count - 1] == '\n') ? count - 1 : count;
+        if (!len)
+                return -EINVAL;
+
+        for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
+                if (strnicmp(page, o2hb_heartbeat_mode_desc[i], len))
+                        continue;
+
+                ret = o2hb_global_hearbeat_mode_set(i);
+                if (!ret)
+                        printk(KERN_NOTICE "ocfs2: Heartbeat mode set to %s\n",
+                               o2hb_heartbeat_mode_desc[i]);
+                return count;
+        }
+
+        return -EINVAL;
+
+}
+
 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
         .attr   = { .ca_owner = THIS_MODULE,
                     .ca_name = "dead_threshold",
@@ -1696,8 +1759,17 @@ static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold
         .store  = o2hb_heartbeat_group_threshold_store,
 };
 
+static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
+        .attr   = { .ca_owner = THIS_MODULE,
+                .ca_name = "mode",
+                .ca_mode = S_IRUGO | S_IWUSR },
+        .show   = o2hb_heartbeat_group_mode_show,
+        .store  = o2hb_heartbeat_group_mode_store,
+};
+
 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
         &o2hb_heartbeat_group_attr_threshold.attr,
+        &o2hb_heartbeat_group_attr_mode.attr,
         NULL,
 };