1 files changed, 464 insertions, 0 deletions
diff --git a/drivers/staging/ramster/cluster/heartbeat.c b/drivers/staging/ramster/cluster/heartbeat.c
new file mode 100644
index 000000000000..00209490756e
--- /dev/null
+++ b/drivers/staging/ramster/cluster/heartbeat.c
@@ -0,0 +1,464 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * Copyright (C) 2004, 2005, 2012 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/configfs.h>
+
+#include "heartbeat.h"
+#include "tcp.h"
+#include "nodemanager.h"
+
+#include "masklog.h"
+
+/*
+ * The first heartbeat pass had one global thread that would serialize all hb
+ * callback calls.  This global serializing sem should only be removed once
+ * we've made sure that all callees can deal with being called concurrently
+ * from multiple hb region threads.
+ */
+static DECLARE_RWSEM(r2hb_callback_sem);
+
+/*
+ * multiple hb threads are watching multiple regions.  A node is live
+ * whenever any of the threads sees activity from the node in its region.
+ */
+static DEFINE_SPINLOCK(r2hb_live_lock);
+static unsigned long r2hb_live_node_bitmap[BITS_TO_LONGS(R2NM_MAX_NODES)];
+
+static struct r2hb_callback {
+	struct list_head list;
+} r2hb_callbacks[R2HB_NUM_CB];
+
+enum r2hb_heartbeat_modes {
+	R2HB_HEARTBEAT_LOCAL		= 0,
+	R2HB_HEARTBEAT_GLOBAL,
+	R2HB_HEARTBEAT_NUM_MODES,
+};
+
+char *r2hb_heartbeat_mode_desc[R2HB_HEARTBEAT_NUM_MODES] = {
+		"local",	/* R2HB_HEARTBEAT_LOCAL */
+		"global",	/* R2HB_HEARTBEAT_GLOBAL */
+};
+
+unsigned int r2hb_dead_threshold = R2HB_DEFAULT_DEAD_THRESHOLD;
+unsigned int r2hb_heartbeat_mode = R2HB_HEARTBEAT_LOCAL;
+
+/* Only sets a new threshold if there are no active regions.
+ *
+ * No locking or otherwise interesting code is required for reading
+ * r2hb_dead_threshold as it can't change once regions are active and
+ * it's not interesting to anyone until then anyway. */
+static void r2hb_dead_threshold_set(unsigned int threshold)
+{
+	if (threshold > R2HB_MIN_DEAD_THRESHOLD) {
+		spin_lock(&r2hb_live_lock);
+		r2hb_dead_threshold = threshold;
+		spin_unlock(&r2hb_live_lock);
+	}
+}
+
+static int r2hb_global_hearbeat_mode_set(unsigned int hb_mode)
+{
+	int ret = -1;
+
+	if (hb_mode < R2HB_HEARTBEAT_NUM_MODES) {
+		spin_lock(&r2hb_live_lock);
+		r2hb_heartbeat_mode = hb_mode;
+		ret = 0;
+		spin_unlock(&r2hb_live_lock);
+	}
+
+	return ret;
+}
+
+void r2hb_exit(void)
+{
+}
+
+int r2hb_init(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(r2hb_callbacks); i++)
+		INIT_LIST_HEAD(&r2hb_callbacks[i].list);
+
+	memset(r2hb_live_node_bitmap, 0, sizeof(r2hb_live_node_bitmap));
+
+	return 0;
+}
+
+/* if we're already in a callback then we're already serialized by the sem */
+static void r2hb_fill_node_map_from_callback(unsigned long *map,
+					     unsigned bytes)
+{
+	BUG_ON(bytes < (BITS_TO_LONGS(R2NM_MAX_NODES) * sizeof(unsigned long)));
+
+	memcpy(map, &r2hb_live_node_bitmap, bytes);
+}
+
+/*
+ * get a map of all nodes that are heartbeating in any regions
+ */
+void r2hb_fill_node_map(unsigned long *map, unsigned bytes)
+{
+	/* callers want to serialize this map and callbacks so that they
+	 * can trust that they don't miss nodes coming to the party */
+	down_read(&r2hb_callback_sem);
+	spin_lock(&r2hb_live_lock);
+	r2hb_fill_node_map_from_callback(map, bytes);
+	spin_unlock(&r2hb_live_lock);
+	up_read(&r2hb_callback_sem);
+}
+EXPORT_SYMBOL_GPL(r2hb_fill_node_map);
+
+/*
+ * heartbeat configfs bits.  The heartbeat set is a default set under
+ * the cluster set in nodemanager.c.
+ */
+
+/* heartbeat set */
+
+struct r2hb_hb_group {
+	struct config_group hs_group;
+	/* some stuff? */
+};
+
+static struct r2hb_hb_group *to_r2hb_hb_group(struct config_group *group)
+{
+	return group ?
+		container_of(group, struct r2hb_hb_group, hs_group)
+		: NULL;
+}
+
+static struct config_item r2hb_config_item;
+
+static struct config_item *r2hb_hb_group_make_item(struct config_group *group,
+							  const char *name)
+{
+	int ret;
+
+	if (strlen(name) > R2HB_MAX_REGION_NAME_LEN) {
+		ret = -ENAMETOOLONG;
+		goto free;
+	}
+
+	config_item_put(&r2hb_config_item);
+
+	return &r2hb_config_item;
+free:
+	return ERR_PTR(ret);
+}
+
+static void r2hb_hb_group_drop_item(struct config_group *group,
+					   struct config_item *item)
+{
+	if (r2hb_global_heartbeat_active()) {
+		printk(KERN_NOTICE "ramster: Heartbeat %s "
+			"on region %s (%s)\n",
+			"stopped/aborted", config_item_name(item),
+			"no region");
+	}
+
+	config_item_put(item);
+}
+
+struct r2hb_hb_group_attribute {
+	struct configfs_attribute attr;
+	ssize_t (*show)(struct r2hb_hb_group *, char *);
+	ssize_t (*store)(struct r2hb_hb_group *, const char *, size_t);
+};
+
+static ssize_t r2hb_hb_group_show(struct config_item *item,
+					 struct configfs_attribute *attr,
+					 char *page)
+{
+	struct r2hb_hb_group *reg = to_r2hb_hb_group(to_config_group(item));
+	struct r2hb_hb_group_attribute *r2hb_hb_group_attr =
+		container_of(attr, struct r2hb_hb_group_attribute, attr);
+	ssize_t ret = 0;
+
+	if (r2hb_hb_group_attr->show)
+		ret = r2hb_hb_group_attr->show(reg, page);
+	return ret;
+}
+
+static ssize_t r2hb_hb_group_store(struct config_item *item,
+					  struct configfs_attribute *attr,
+					  const char *page, size_t count)
+{
+	struct r2hb_hb_group *reg = to_r2hb_hb_group(to_config_group(item));
+	struct r2hb_hb_group_attribute *r2hb_hb_group_attr =
+		container_of(attr, struct r2hb_hb_group_attribute, attr);
+	ssize_t ret = -EINVAL;
+
+	if (r2hb_hb_group_attr->store)
+		ret = r2hb_hb_group_attr->store(reg, page, count);
+	return ret;
+}
+
+static ssize_t r2hb_hb_group_threshold_show(struct r2hb_hb_group *group,
+						     char *page)
+{
+	return sprintf(page, "%u\n", r2hb_dead_threshold);
+}
+
+static ssize_t r2hb_hb_group_threshold_store(struct r2hb_hb_group *group,
+						    const char *page,
+						    size_t count)
+{
+	unsigned long tmp;
+	char *p = (char *)page;
+	int err;
+
+	err = kstrtoul(p, 10, &tmp);
+	if (err)
+		return err;
+
+	/* this will validate ranges for us. */
+	r2hb_dead_threshold_set((unsigned int) tmp);
+
+	return count;
+}
+
+static
+ssize_t r2hb_hb_group_mode_show(struct r2hb_hb_group *group,
+				       char *page)
+{
+	return sprintf(page, "%s\n",
+		       r2hb_heartbeat_mode_desc[r2hb_heartbeat_mode]);
+}
+
+static
+ssize_t r2hb_hb_group_mode_store(struct r2hb_hb_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 < R2HB_HEARTBEAT_NUM_MODES; ++i) {
+		if (strnicmp(page, r2hb_heartbeat_mode_desc[i], len))
+			continue;
+
+		ret = r2hb_global_hearbeat_mode_set(i);
+		if (!ret)
+			printk(KERN_NOTICE "ramster: Heartbeat mode "
+						"set to %s\n",
+			       r2hb_heartbeat_mode_desc[i]);
+		return count;
+	}
+
+	return -EINVAL;
+
+}
+
+static struct r2hb_hb_group_attribute r2hb_hb_group_attr_threshold = {
+	.attr	= { .ca_owner = THIS_MODULE,
+		    .ca_name = "dead_threshold",
+		    .ca_mode = S_IRUGO | S_IWUSR },
+	.show	= r2hb_hb_group_threshold_show,
+	.store	= r2hb_hb_group_threshold_store,
+};
+
+static struct r2hb_hb_group_attribute r2hb_hb_group_attr_mode = {
+	.attr   = { .ca_owner = THIS_MODULE,
+		.ca_name = "mode",
+		.ca_mode = S_IRUGO | S_IWUSR },
+	.show   = r2hb_hb_group_mode_show,
+	.store  = r2hb_hb_group_mode_store,
+};
+
+static struct configfs_attribute *r2hb_hb_group_attrs[] = {
+	&r2hb_hb_group_attr_threshold.attr,
+	&r2hb_hb_group_attr_mode.attr,
+	NULL,
+};
+
+static struct configfs_item_operations r2hb_hearbeat_group_item_ops = {
+	.show_attribute		= r2hb_hb_group_show,
+	.store_attribute	= r2hb_hb_group_store,
+};
+
+static struct configfs_group_operations r2hb_hb_group_group_ops = {
+	.make_item	= r2hb_hb_group_make_item,
+	.drop_item	= r2hb_hb_group_drop_item,
+};
+
+static struct config_item_type r2hb_hb_group_type = {
+	.ct_group_ops	= &r2hb_hb_group_group_ops,
+	.ct_item_ops	= &r2hb_hearbeat_group_item_ops,
+	.ct_attrs	= r2hb_hb_group_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+/* this is just here to avoid touching group in heartbeat.h which the
+ * entire damn world #includes */
+struct config_group *r2hb_alloc_hb_set(void)
+{
+	struct r2hb_hb_group *hs = NULL;
+	struct config_group *ret = NULL;
+
+	hs = kzalloc(sizeof(struct r2hb_hb_group), GFP_KERNEL);
+	if (hs == NULL)
+		goto out;
+
+	config_group_init_type_name(&hs->hs_group, "heartbeat",
+				    &r2hb_hb_group_type);
+
+	ret = &hs->hs_group;
+out:
+	if (ret == NULL)
+		kfree(hs);
+	return ret;
+}
+
+void r2hb_free_hb_set(struct config_group *group)
+{
+	struct r2hb_hb_group *hs = to_r2hb_hb_group(group);
+	kfree(hs);
+}
+
+/* hb callback registration and issuing */
+
+static struct r2hb_callback *hbcall_from_type(enum r2hb_callback_type type)
+{
+	if (type == R2HB_NUM_CB)
+		return ERR_PTR(-EINVAL);
+
+	return &r2hb_callbacks[type];
+}
+
+void r2hb_setup_callback(struct r2hb_callback_func *hc,
+			 enum r2hb_callback_type type,
+			 r2hb_cb_func *func,
+			 void *data,
+			 int priority)
+{
+	INIT_LIST_HEAD(&hc->hc_item);
+	hc->hc_func = func;
+	hc->hc_data = data;
+	hc->hc_priority = priority;
+	hc->hc_type = type;
+	hc->hc_magic = R2HB_CB_MAGIC;
+}
+EXPORT_SYMBOL_GPL(r2hb_setup_callback);
+
+int r2hb_register_callback(const char *region_uuid,
+			   struct r2hb_callback_func *hc)
+{
+	struct r2hb_callback_func *tmp;
+	struct list_head *iter;
+	struct r2hb_callback *hbcall;
+	int ret;
+
+	BUG_ON(hc->hc_magic != R2HB_CB_MAGIC);
+	BUG_ON(!list_empty(&hc->hc_item));
+
+	hbcall = hbcall_from_type(hc->hc_type);
+	if (IS_ERR(hbcall)) {
+		ret = PTR_ERR(hbcall);
+		goto out;
+	}
+
+	down_write(&r2hb_callback_sem);
+
+	list_for_each(iter, &hbcall->list) {
+		tmp = list_entry(iter, struct r2hb_callback_func, hc_item);
+		if (hc->hc_priority < tmp->hc_priority) {
+			list_add_tail(&hc->hc_item, iter);
+			break;
+		}
+	}
+	if (list_empty(&hc->hc_item))
+		list_add_tail(&hc->hc_item, &hbcall->list);
+
+	up_write(&r2hb_callback_sem);
+	ret = 0;
+out:
+	mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
+	     ret, __builtin_return_address(0), hc);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(r2hb_register_callback);
+
+void r2hb_unregister_callback(const char *region_uuid,
+			      struct r2hb_callback_func *hc)
+{
+	BUG_ON(hc->hc_magic != R2HB_CB_MAGIC);
+
+	mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
+	     __builtin_return_address(0), hc);
+
+	/* XXX Can this happen _with_ a region reference? */
+	if (list_empty(&hc->hc_item))
+		return;
+
+	down_write(&r2hb_callback_sem);
+
+	list_del_init(&hc->hc_item);
+
+	up_write(&r2hb_callback_sem);
+}
+EXPORT_SYMBOL_GPL(r2hb_unregister_callback);
+
+int r2hb_check_node_heartbeating_from_callback(u8 node_num)
+{
+	unsigned long testing_map[BITS_TO_LONGS(R2NM_MAX_NODES)];
+
+	r2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
+	if (!test_bit(node_num, testing_map)) {
+		mlog(ML_HEARTBEAT,
+		     "node (%u) does not have heartbeating enabled.\n",
+		     node_num);
+		return 0;
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(r2hb_check_node_heartbeating_from_callback);
+
+void r2hb_stop_all_regions(void)
+{
+}
+EXPORT_SYMBOL_GPL(r2hb_stop_all_regions);
+
+/*
+ * this is just a hack until we get the plumbing which flips file systems
+ * read only and drops the hb ref instead of killing the node dead.
+ */
+int r2hb_global_heartbeat_active(void)
+{
+	return (r2hb_heartbeat_mode == R2HB_HEARTBEAT_GLOBAL);
+}
+EXPORT_SYMBOL(r2hb_global_heartbeat_active);
+
+/* added for RAMster */
+void r2hb_manual_set_node_heartbeating(int node_num)
+{
+	if (node_num < R2NM_MAX_NODES)
+		set_bit(node_num, r2hb_live_node_bitmap);
+}
+EXPORT_SYMBOL(r2hb_manual_set_node_heartbeating);