Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / ocfs2 / dlm / dlmdomain.c
diff --git a/kernel/fs/ocfs2/dlm/dlmdomain.c b/kernel/fs/ocfs2/dlm/dlmdomain.c
new file mode 100644 (file)
index 0000000..7df88a6
--- /dev/null
@@ -0,0 +1,2375 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * dlmdomain.c
+ *
+ * defines domain join / leave apis
+ *
+ * Copyright (C) 2004 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/module.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/highmem.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/debugfs.h>
+
+#include "cluster/heartbeat.h"
+#include "cluster/nodemanager.h"
+#include "cluster/tcp.h"
+
+#include "dlmapi.h"
+#include "dlmcommon.h"
+#include "dlmdomain.h"
+#include "dlmdebug.h"
+
+#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
+#include "cluster/masklog.h"
+
+/*
+ * ocfs2 node maps are array of long int, which limits to send them freely
+ * across the wire due to endianness issues. To workaround this, we convert
+ * long ints to byte arrays. Following 3 routines are helper functions to
+ * set/test/copy bits within those array of bytes
+ */
+static inline void byte_set_bit(u8 nr, u8 map[])
+{
+       map[nr >> 3] |= (1UL << (nr & 7));
+}
+
+static inline int byte_test_bit(u8 nr, u8 map[])
+{
+       return ((1UL << (nr & 7)) & (map[nr >> 3])) != 0;
+}
+
+static inline void byte_copymap(u8 dmap[], unsigned long smap[],
+                       unsigned int sz)
+{
+       unsigned int nn;
+
+       if (!sz)
+               return;
+
+       memset(dmap, 0, ((sz + 7) >> 3));
+       for (nn = 0 ; nn < sz; nn++)
+               if (test_bit(nn, smap))
+                       byte_set_bit(nn, dmap);
+}
+
+static void dlm_free_pagevec(void **vec, int pages)
+{
+       while (pages--)
+               free_page((unsigned long)vec[pages]);
+       kfree(vec);
+}
+
+static void **dlm_alloc_pagevec(int pages)
+{
+       void **vec = kmalloc(pages * sizeof(void *), GFP_KERNEL);
+       int i;
+
+       if (!vec)
+               return NULL;
+
+       for (i = 0; i < pages; i++)
+               if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
+                       goto out_free;
+
+       mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %lu buckets per page\n",
+            pages, (unsigned long)DLM_HASH_PAGES,
+            (unsigned long)DLM_BUCKETS_PER_PAGE);
+       return vec;
+out_free:
+       dlm_free_pagevec(vec, i);
+       return NULL;
+}
+
+/*
+ *
+ * spinlock lock ordering: if multiple locks are needed, obey this ordering:
+ *    dlm_domain_lock
+ *    struct dlm_ctxt->spinlock
+ *    struct dlm_lock_resource->spinlock
+ *    struct dlm_ctxt->master_lock
+ *    struct dlm_ctxt->ast_lock
+ *    dlm_master_list_entry->spinlock
+ *    dlm_lock->spinlock
+ *
+ */
+
+DEFINE_SPINLOCK(dlm_domain_lock);
+LIST_HEAD(dlm_domains);
+static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
+
+/*
+ * The supported protocol version for DLM communication.  Running domains
+ * will have a negotiated version with the same major number and a minor
+ * number equal or smaller.  The dlm_ctxt->dlm_locking_proto field should
+ * be used to determine what a running domain is actually using.
+ *
+ * New in version 1.1:
+ *     - Message DLM_QUERY_REGION added to support global heartbeat
+ *     - Message DLM_QUERY_NODEINFO added to allow online node removes
+ * New in version 1.2:
+ *     - Message DLM_BEGIN_EXIT_DOMAIN_MSG added to mark start of exit domain
+ */
+static const struct dlm_protocol_version dlm_protocol = {
+       .pv_major = 1,
+       .pv_minor = 2,
+};
+
+#define DLM_DOMAIN_BACKOFF_MS 200
+
+static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
+                                 void **ret_data);
+static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
+                                    void **ret_data);
+static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
+                                  void **ret_data);
+static int dlm_query_region_handler(struct o2net_msg *msg, u32 len,
+                                   void *data, void **ret_data);
+static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
+                                  void **ret_data);
+static int dlm_protocol_compare(struct dlm_protocol_version *existing,
+                               struct dlm_protocol_version *request);
+
+static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
+
+void __dlm_unhash_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
+{
+       if (hlist_unhashed(&res->hash_node))
+               return;
+
+       mlog(0, "%s: Unhash res %.*s\n", dlm->name, res->lockname.len,
+            res->lockname.name);
+       hlist_del_init(&res->hash_node);
+       dlm_lockres_put(res);
+}
+
+void __dlm_insert_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
+{
+       struct hlist_head *bucket;
+       struct qstr *q;
+
+       assert_spin_locked(&dlm->spinlock);
+
+       q = &res->lockname;
+       bucket = dlm_lockres_hash(dlm, q->hash);
+
+       /* get a reference for our hashtable */
+       dlm_lockres_get(res);
+
+       hlist_add_head(&res->hash_node, bucket);
+
+       mlog(0, "%s: Hash res %.*s\n", dlm->name, res->lockname.len,
+            res->lockname.name);
+}
+
+struct dlm_lock_resource * __dlm_lookup_lockres_full(struct dlm_ctxt *dlm,
+                                                    const char *name,
+                                                    unsigned int len,
+                                                    unsigned int hash)
+{
+       struct hlist_head *bucket;
+       struct dlm_lock_resource *res;
+
+       mlog(0, "%.*s\n", len, name);
+
+       assert_spin_locked(&dlm->spinlock);
+
+       bucket = dlm_lockres_hash(dlm, hash);
+
+       hlist_for_each_entry(res, bucket, hash_node) {
+               if (res->lockname.name[0] != name[0])
+                       continue;
+               if (unlikely(res->lockname.len != len))
+                       continue;
+               if (memcmp(res->lockname.name + 1, name + 1, len - 1))
+                       continue;
+               dlm_lockres_get(res);
+               return res;
+       }
+       return NULL;
+}
+
+/* intended to be called by functions which do not care about lock
+ * resources which are being purged (most net _handler functions).
+ * this will return NULL for any lock resource which is found but
+ * currently in the process of dropping its mastery reference.
+ * use __dlm_lookup_lockres_full when you need the lock resource
+ * regardless (e.g. dlm_get_lock_resource) */
+struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
+                                               const char *name,
+                                               unsigned int len,
+                                               unsigned int hash)
+{
+       struct dlm_lock_resource *res = NULL;
+
+       mlog(0, "%.*s\n", len, name);
+
+       assert_spin_locked(&dlm->spinlock);
+
+       res = __dlm_lookup_lockres_full(dlm, name, len, hash);
+       if (res) {
+               spin_lock(&res->spinlock);
+               if (res->state & DLM_LOCK_RES_DROPPING_REF) {
+                       spin_unlock(&res->spinlock);
+                       dlm_lockres_put(res);
+                       return NULL;
+               }
+               spin_unlock(&res->spinlock);
+       }
+
+       return res;
+}
+
+struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
+                                   const char *name,
+                                   unsigned int len)
+{
+       struct dlm_lock_resource *res;
+       unsigned int hash = dlm_lockid_hash(name, len);
+
+       spin_lock(&dlm->spinlock);
+       res = __dlm_lookup_lockres(dlm, name, len, hash);
+       spin_unlock(&dlm->spinlock);
+       return res;
+}
+
+static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
+{
+       struct dlm_ctxt *tmp;
+
+       assert_spin_locked(&dlm_domain_lock);
+
+       /* tmp->name here is always NULL terminated,
+        * but domain may not be! */
+       list_for_each_entry(tmp, &dlm_domains, list) {
+               if (strlen(tmp->name) == len &&
+                   memcmp(tmp->name, domain, len)==0)
+                       return tmp;
+       }
+
+       return NULL;
+}
+
+/* For null terminated domain strings ONLY */
+static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
+{
+       assert_spin_locked(&dlm_domain_lock);
+
+       return __dlm_lookup_domain_full(domain, strlen(domain));
+}
+
+
+/* returns true on one of two conditions:
+ * 1) the domain does not exist
+ * 2) the domain exists and it's state is "joined" */
+static int dlm_wait_on_domain_helper(const char *domain)
+{
+       int ret = 0;
+       struct dlm_ctxt *tmp = NULL;
+
+       spin_lock(&dlm_domain_lock);
+
+       tmp = __dlm_lookup_domain(domain);
+       if (!tmp)
+               ret = 1;
+       else if (tmp->dlm_state == DLM_CTXT_JOINED)
+               ret = 1;
+
+       spin_unlock(&dlm_domain_lock);
+       return ret;
+}
+
+static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
+{
+       dlm_destroy_debugfs_subroot(dlm);
+
+       if (dlm->lockres_hash)
+               dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
+
+       if (dlm->master_hash)
+               dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
+
+       kfree(dlm->name);
+       kfree(dlm);
+}
+
+/* A little strange - this function will be called while holding
+ * dlm_domain_lock and is expected to be holding it on the way out. We
+ * will however drop and reacquire it multiple times */
+static void dlm_ctxt_release(struct kref *kref)
+{
+       struct dlm_ctxt *dlm;
+
+       dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
+
+       BUG_ON(dlm->num_joins);
+       BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
+
+       /* we may still be in the list if we hit an error during join. */
+       list_del_init(&dlm->list);
+
+       spin_unlock(&dlm_domain_lock);
+
+       mlog(0, "freeing memory from domain %s\n", dlm->name);
+
+       wake_up(&dlm_domain_events);
+
+       dlm_free_ctxt_mem(dlm);
+
+       spin_lock(&dlm_domain_lock);
+}
+
+void dlm_put(struct dlm_ctxt *dlm)
+{
+       spin_lock(&dlm_domain_lock);
+       kref_put(&dlm->dlm_refs, dlm_ctxt_release);
+       spin_unlock(&dlm_domain_lock);
+}
+
+static void __dlm_get(struct dlm_ctxt *dlm)
+{
+       kref_get(&dlm->dlm_refs);
+}
+
+/* given a questionable reference to a dlm object, gets a reference if
+ * it can find it in the list, otherwise returns NULL in which case
+ * you shouldn't trust your pointer. */
+struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
+{
+       struct dlm_ctxt *target;
+       struct dlm_ctxt *ret = NULL;
+
+       spin_lock(&dlm_domain_lock);
+
+       list_for_each_entry(target, &dlm_domains, list) {
+               if (target == dlm) {
+                       __dlm_get(target);
+                       ret = target;
+                       break;
+               }
+       }
+
+       spin_unlock(&dlm_domain_lock);
+
+       return ret;
+}
+
+int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
+{
+       int ret;
+
+       spin_lock(&dlm_domain_lock);
+       ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
+               (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
+       spin_unlock(&dlm_domain_lock);
+
+       return ret;
+}
+
+static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
+{
+       if (dlm->dlm_worker) {
+               flush_workqueue(dlm->dlm_worker);
+               destroy_workqueue(dlm->dlm_worker);
+               dlm->dlm_worker = NULL;
+       }
+}
+
+static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
+{
+       dlm_unregister_domain_handlers(dlm);
+       dlm_debug_shutdown(dlm);
+       dlm_complete_thread(dlm);
+       dlm_complete_recovery_thread(dlm);
+       dlm_destroy_dlm_worker(dlm);
+
+       /* We've left the domain. Now we can take ourselves out of the
+        * list and allow the kref stuff to help us free the
+        * memory. */
+       spin_lock(&dlm_domain_lock);
+       list_del_init(&dlm->list);
+       spin_unlock(&dlm_domain_lock);
+
+       /* Wake up anyone waiting for us to remove this domain */
+       wake_up(&dlm_domain_events);
+}
+
+static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
+{
+       int i, num, n, ret = 0;
+       struct dlm_lock_resource *res;
+       struct hlist_node *iter;
+       struct hlist_head *bucket;
+       int dropped;
+
+       mlog(0, "Migrating locks from domain %s\n", dlm->name);
+
+       num = 0;
+       spin_lock(&dlm->spinlock);
+       for (i = 0; i < DLM_HASH_BUCKETS; i++) {
+redo_bucket:
+               n = 0;
+               bucket = dlm_lockres_hash(dlm, i);
+               iter = bucket->first;
+               while (iter) {
+                       n++;
+                       res = hlist_entry(iter, struct dlm_lock_resource,
+                                         hash_node);
+                       dlm_lockres_get(res);
+                       /* migrate, if necessary.  this will drop the dlm
+                        * spinlock and retake it if it does migration. */
+                       dropped = dlm_empty_lockres(dlm, res);
+
+                       spin_lock(&res->spinlock);
+                       if (dropped)
+                               __dlm_lockres_calc_usage(dlm, res);
+                       else
+                               iter = res->hash_node.next;
+                       spin_unlock(&res->spinlock);
+
+                       dlm_lockres_put(res);
+
+                       if (dropped) {
+                               cond_resched_lock(&dlm->spinlock);
+                               goto redo_bucket;
+                       }
+               }
+               cond_resched_lock(&dlm->spinlock);
+               num += n;
+       }
+       spin_unlock(&dlm->spinlock);
+       wake_up(&dlm->dlm_thread_wq);
+
+       /* let the dlm thread take care of purging, keep scanning until
+        * nothing remains in the hash */
+       if (num) {
+               mlog(0, "%s: %d lock resources in hash last pass\n",
+                    dlm->name, num);
+               ret = -EAGAIN;
+       }
+       mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
+       return ret;
+}
+
+static int dlm_no_joining_node(struct dlm_ctxt *dlm)
+{
+       int ret;
+
+       spin_lock(&dlm->spinlock);
+       ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
+       spin_unlock(&dlm->spinlock);
+
+       return ret;
+}
+
+static int dlm_begin_exit_domain_handler(struct o2net_msg *msg, u32 len,
+                                        void *data, void **ret_data)
+{
+       struct dlm_ctxt *dlm = data;
+       unsigned int node;
+       struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
+
+       if (!dlm_grab(dlm))
+               return 0;
+
+       node = exit_msg->node_idx;
+       mlog(0, "%s: Node %u sent a begin exit domain message\n", dlm->name, node);
+
+       spin_lock(&dlm->spinlock);
+       set_bit(node, dlm->exit_domain_map);
+       spin_unlock(&dlm->spinlock);
+
+       dlm_put(dlm);
+
+       return 0;
+}
+
+static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
+{
+       /* Yikes, a double spinlock! I need domain_lock for the dlm
+        * state and the dlm spinlock for join state... Sorry! */
+again:
+       spin_lock(&dlm_domain_lock);
+       spin_lock(&dlm->spinlock);
+
+       if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
+               mlog(0, "Node %d is joining, we wait on it.\n",
+                         dlm->joining_node);
+               spin_unlock(&dlm->spinlock);
+               spin_unlock(&dlm_domain_lock);
+
+               wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
+               goto again;
+       }
+
+       dlm->dlm_state = DLM_CTXT_LEAVING;
+       spin_unlock(&dlm->spinlock);
+       spin_unlock(&dlm_domain_lock);
+}
+
+static void __dlm_print_nodes(struct dlm_ctxt *dlm)
+{
+       int node = -1, num = 0;
+
+       assert_spin_locked(&dlm->spinlock);
+
+       printk("( ");
+       while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
+                                    node + 1)) < O2NM_MAX_NODES) {
+               printk("%d ", node);
+               ++num;
+       }
+       printk(") %u nodes\n", num);
+}
+
+static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
+                                  void **ret_data)
+{
+       struct dlm_ctxt *dlm = data;
+       unsigned int node;
+       struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
+
+       mlog(0, "%p %u %p", msg, len, data);
+
+       if (!dlm_grab(dlm))
+               return 0;
+
+       node = exit_msg->node_idx;
+
+       spin_lock(&dlm->spinlock);
+       clear_bit(node, dlm->domain_map);
+       clear_bit(node, dlm->exit_domain_map);
+       printk(KERN_NOTICE "o2dlm: Node %u leaves domain %s ", node, dlm->name);
+       __dlm_print_nodes(dlm);
+
+       /* notify anything attached to the heartbeat events */
+       dlm_hb_event_notify_attached(dlm, node, 0);
+
+       spin_unlock(&dlm->spinlock);
+
+       dlm_put(dlm);
+
+       return 0;
+}
+
+static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm, u32 msg_type,
+                                   unsigned int node)
+{
+       int status;
+       struct dlm_exit_domain leave_msg;
+
+       mlog(0, "%s: Sending domain exit message %u to node %u\n", dlm->name,
+            msg_type, node);
+
+       memset(&leave_msg, 0, sizeof(leave_msg));
+       leave_msg.node_idx = dlm->node_num;
+
+       status = o2net_send_message(msg_type, dlm->key, &leave_msg,
+                                   sizeof(leave_msg), node, NULL);
+       if (status < 0)
+               mlog(ML_ERROR, "Error %d sending domain exit message %u "
+                    "to node %u on domain %s\n", status, msg_type, node,
+                    dlm->name);
+
+       return status;
+}
+
+static void dlm_begin_exit_domain(struct dlm_ctxt *dlm)
+{
+       int node = -1;
+
+       /* Support for begin exit domain was added in 1.2 */
+       if (dlm->dlm_locking_proto.pv_major == 1 &&
+           dlm->dlm_locking_proto.pv_minor < 2)
+               return;
+
+       /*
+        * Unlike DLM_EXIT_DOMAIN_MSG, DLM_BEGIN_EXIT_DOMAIN_MSG is purely
+        * informational. Meaning if a node does not receive the message,
+        * so be it.
+        */
+       spin_lock(&dlm->spinlock);
+       while (1) {
+               node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES, node + 1);
+               if (node >= O2NM_MAX_NODES)
+                       break;
+               if (node == dlm->node_num)
+                       continue;
+
+               spin_unlock(&dlm->spinlock);
+               dlm_send_one_domain_exit(dlm, DLM_BEGIN_EXIT_DOMAIN_MSG, node);
+               spin_lock(&dlm->spinlock);
+       }
+       spin_unlock(&dlm->spinlock);
+}
+
+static void dlm_leave_domain(struct dlm_ctxt *dlm)
+{
+       int node, clear_node, status;
+
+       /* At this point we've migrated away all our locks and won't
+        * accept mastership of new ones. The dlm is responsible for
+        * almost nothing now. We make sure not to confuse any joining
+        * nodes and then commence shutdown procedure. */
+
+       spin_lock(&dlm->spinlock);
+       /* Clear ourselves from the domain map */
+       clear_bit(dlm->node_num, dlm->domain_map);
+       while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
+                                    0)) < O2NM_MAX_NODES) {
+               /* Drop the dlm spinlock. This is safe wrt the domain_map.
+                * -nodes cannot be added now as the
+                *   query_join_handlers knows to respond with OK_NO_MAP
+                * -we catch the right network errors if a node is
+                *   removed from the map while we're sending him the
+                *   exit message. */
+               spin_unlock(&dlm->spinlock);
+
+               clear_node = 1;
+
+               status = dlm_send_one_domain_exit(dlm, DLM_EXIT_DOMAIN_MSG,
+                                                 node);
+               if (status < 0 &&
+                   status != -ENOPROTOOPT &&
+                   status != -ENOTCONN) {
+                       mlog(ML_NOTICE, "Error %d sending domain exit message "
+                            "to node %d\n", status, node);
+
+                       /* Not sure what to do here but lets sleep for
+                        * a bit in case this was a transient
+                        * error... */
+                       msleep(DLM_DOMAIN_BACKOFF_MS);
+                       clear_node = 0;
+               }
+
+               spin_lock(&dlm->spinlock);
+               /* If we're not clearing the node bit then we intend
+                * to loop back around to try again. */
+               if (clear_node)
+                       clear_bit(node, dlm->domain_map);
+       }
+       spin_unlock(&dlm->spinlock);
+}
+
+int dlm_shutting_down(struct dlm_ctxt *dlm)
+{
+       int ret = 0;
+
+       spin_lock(&dlm_domain_lock);
+
+       if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
+               ret = 1;
+
+       spin_unlock(&dlm_domain_lock);
+
+       return ret;
+}
+
+void dlm_unregister_domain(struct dlm_ctxt *dlm)
+{
+       int leave = 0;
+       struct dlm_lock_resource *res;
+
+       spin_lock(&dlm_domain_lock);
+       BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
+       BUG_ON(!dlm->num_joins);
+
+       dlm->num_joins--;
+       if (!dlm->num_joins) {
+               /* We mark it "in shutdown" now so new register
+                * requests wait until we've completely left the
+                * domain. Don't use DLM_CTXT_LEAVING yet as we still
+                * want new domain joins to communicate with us at
+                * least until we've completed migration of our
+                * resources. */
+               dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
+               leave = 1;
+       }
+       spin_unlock(&dlm_domain_lock);
+
+       if (leave) {
+               mlog(0, "shutting down domain %s\n", dlm->name);
+               dlm_begin_exit_domain(dlm);
+
+               /* We changed dlm state, notify the thread */
+               dlm_kick_thread(dlm, NULL);
+
+               while (dlm_migrate_all_locks(dlm)) {
+                       /* Give dlm_thread time to purge the lockres' */
+                       msleep(500);
+                       mlog(0, "%s: more migration to do\n", dlm->name);
+               }
+
+               /* This list should be empty. If not, print remaining lockres */
+               if (!list_empty(&dlm->tracking_list)) {
+                       mlog(ML_ERROR, "Following lockres' are still on the "
+                            "tracking list:\n");
+                       list_for_each_entry(res, &dlm->tracking_list, tracking)
+                               dlm_print_one_lock_resource(res);
+               }
+
+               dlm_mark_domain_leaving(dlm);
+               dlm_leave_domain(dlm);
+               printk(KERN_NOTICE "o2dlm: Leaving domain %s\n", dlm->name);
+               dlm_force_free_mles(dlm);
+               dlm_complete_dlm_shutdown(dlm);
+       }
+       dlm_put(dlm);
+}
+EXPORT_SYMBOL_GPL(dlm_unregister_domain);
+
+static int dlm_query_join_proto_check(char *proto_type, int node,
+                                     struct dlm_protocol_version *ours,
+                                     struct dlm_protocol_version *request)
+{
+       int rc;
+       struct dlm_protocol_version proto = *request;
+
+       if (!dlm_protocol_compare(ours, &proto)) {
+               mlog(0,
+                    "node %u wanted to join with %s locking protocol "
+                    "%u.%u, we respond with %u.%u\n",
+                    node, proto_type,
+                    request->pv_major,
+                    request->pv_minor,
+                    proto.pv_major, proto.pv_minor);
+               request->pv_minor = proto.pv_minor;
+               rc = 0;
+       } else {
+               mlog(ML_NOTICE,
+                    "Node %u wanted to join with %s locking "
+                    "protocol %u.%u, but we have %u.%u, disallowing\n",
+                    node, proto_type,
+                    request->pv_major,
+                    request->pv_minor,
+                    ours->pv_major,
+                    ours->pv_minor);
+               rc = 1;
+       }
+
+       return rc;
+}
+
+/*
+ * struct dlm_query_join_packet is made up of four one-byte fields.  They
+ * are effectively in big-endian order already.  However, little-endian
+ * machines swap them before putting the packet on the wire (because
+ * query_join's response is a status, and that status is treated as a u32
+ * on the wire).  Thus, a big-endian and little-endian machines will treat
+ * this structure differently.
+ *
+ * The solution is to have little-endian machines swap the structure when
+ * converting from the structure to the u32 representation.  This will
+ * result in the structure having the correct format on the wire no matter
+ * the host endian format.
+ */
+static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
+                                         u32 *wire)
+{
+       union dlm_query_join_response response;
+
+       response.packet = *packet;
+       *wire = be32_to_cpu(response.intval);
+}
+
+static void dlm_query_join_wire_to_packet(u32 wire,
+                                         struct dlm_query_join_packet *packet)
+{
+       union dlm_query_join_response response;
+
+       response.intval = cpu_to_be32(wire);
+       *packet = response.packet;
+}
+
+static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
+                                 void **ret_data)
+{
+       struct dlm_query_join_request *query;
+       struct dlm_query_join_packet packet = {
+               .code = JOIN_DISALLOW,
+       };
+       struct dlm_ctxt *dlm = NULL;
+       u32 response;
+       u8 nodenum;
+
+       query = (struct dlm_query_join_request *) msg->buf;
+
+       mlog(0, "node %u wants to join domain %s\n", query->node_idx,
+                 query->domain);
+
+       /*
+        * If heartbeat doesn't consider the node live, tell it
+        * to back off and try again.  This gives heartbeat a chance
+        * to catch up.
+        */
+       if (!o2hb_check_node_heartbeating_no_sem(query->node_idx)) {
+               mlog(0, "node %u is not in our live map yet\n",
+                    query->node_idx);
+
+               packet.code = JOIN_DISALLOW;
+               goto respond;
+       }
+
+       packet.code = JOIN_OK_NO_MAP;
+
+       spin_lock(&dlm_domain_lock);
+       dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
+       if (!dlm)
+               goto unlock_respond;
+
+       /*
+        * There is a small window where the joining node may not see the
+        * node(s) that just left but still part of the cluster. DISALLOW
+        * join request if joining node has different node map.
+        */
+       nodenum=0;
+       while (nodenum < O2NM_MAX_NODES) {
+               if (test_bit(nodenum, dlm->domain_map)) {
+                       if (!byte_test_bit(nodenum, query->node_map)) {
+                               mlog(0, "disallow join as node %u does not "
+                                    "have node %u in its nodemap\n",
+                                    query->node_idx, nodenum);
+                               packet.code = JOIN_DISALLOW;
+                               goto unlock_respond;
+                       }
+               }
+               nodenum++;
+       }
+
+       /* Once the dlm ctxt is marked as leaving then we don't want
+        * to be put in someone's domain map.
+        * Also, explicitly disallow joining at certain troublesome
+        * times (ie. during recovery). */
+       if (dlm->dlm_state != DLM_CTXT_LEAVING) {
+               int bit = query->node_idx;
+               spin_lock(&dlm->spinlock);
+
+               if (dlm->dlm_state == DLM_CTXT_NEW &&
+                   dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
+                       /*If this is a brand new context and we
+                        * haven't started our join process yet, then
+                        * the other node won the race. */
+                       packet.code = JOIN_OK_NO_MAP;
+               } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
+                       /* Disallow parallel joins. */
+                       packet.code = JOIN_DISALLOW;
+               } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
+                       mlog(0, "node %u trying to join, but recovery "
+                            "is ongoing.\n", bit);
+                       packet.code = JOIN_DISALLOW;
+               } else if (test_bit(bit, dlm->recovery_map)) {
+                       mlog(0, "node %u trying to join, but it "
+                            "still needs recovery.\n", bit);
+                       packet.code = JOIN_DISALLOW;
+               } else if (test_bit(bit, dlm->domain_map)) {
+                       mlog(0, "node %u trying to join, but it "
+                            "is still in the domain! needs recovery?\n",
+                            bit);
+                       packet.code = JOIN_DISALLOW;
+               } else {
+                       /* Alright we're fully a part of this domain
+                        * so we keep some state as to who's joining
+                        * and indicate to him that needs to be fixed
+                        * up. */
+
+                       /* Make sure we speak compatible locking protocols.  */
+                       if (dlm_query_join_proto_check("DLM", bit,
+                                                      &dlm->dlm_locking_proto,
+                                                      &query->dlm_proto)) {
+                               packet.code = JOIN_PROTOCOL_MISMATCH;
+                       } else if (dlm_query_join_proto_check("fs", bit,
+                                                             &dlm->fs_locking_proto,
+                                                             &query->fs_proto)) {
+                               packet.code = JOIN_PROTOCOL_MISMATCH;
+                       } else {
+                               packet.dlm_minor = query->dlm_proto.pv_minor;
+                               packet.fs_minor = query->fs_proto.pv_minor;
+                               packet.code = JOIN_OK;
+                               __dlm_set_joining_node(dlm, query->node_idx);
+                       }
+               }
+
+               spin_unlock(&dlm->spinlock);
+       }
+unlock_respond:
+       spin_unlock(&dlm_domain_lock);
+
+respond:
+       mlog(0, "We respond with %u\n", packet.code);
+
+       dlm_query_join_packet_to_wire(&packet, &response);
+       return response;
+}
+
+static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
+                                    void **ret_data)
+{
+       struct dlm_assert_joined *assert;
+       struct dlm_ctxt *dlm = NULL;
+
+       assert = (struct dlm_assert_joined *) msg->buf;
+
+       mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
+                 assert->domain);
+
+       spin_lock(&dlm_domain_lock);
+       dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
+       /* XXX should we consider no dlm ctxt an error? */
+       if (dlm) {
+               spin_lock(&dlm->spinlock);
+
+               /* Alright, this node has officially joined our
+                * domain. Set him in the map and clean up our
+                * leftover join state. */
+               BUG_ON(dlm->joining_node != assert->node_idx);
+
+               if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
+                       mlog(0, "dlm recovery is ongoing, disallow join\n");
+                       spin_unlock(&dlm->spinlock);
+                       spin_unlock(&dlm_domain_lock);
+                       return -EAGAIN;
+               }
+
+               set_bit(assert->node_idx, dlm->domain_map);
+               clear_bit(assert->node_idx, dlm->exit_domain_map);
+               __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
+
+               printk(KERN_NOTICE "o2dlm: Node %u joins domain %s ",
+                      assert->node_idx, dlm->name);
+               __dlm_print_nodes(dlm);
+
+               /* notify anything attached to the heartbeat events */
+               dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
+
+               spin_unlock(&dlm->spinlock);
+       }
+       spin_unlock(&dlm_domain_lock);
+
+       return 0;
+}
+
+static int dlm_match_regions(struct dlm_ctxt *dlm,
+                            struct dlm_query_region *qr,
+                            char *local, int locallen)
+{
+       char *remote = qr->qr_regions;
+       char *l, *r;
+       int localnr, i, j, foundit;
+       int status = 0;
+
+       if (!o2hb_global_heartbeat_active()) {
+               if (qr->qr_numregions) {
+                       mlog(ML_ERROR, "Domain %s: Joining node %d has global "
+                            "heartbeat enabled but local node %d does not\n",
+                            qr->qr_domain, qr->qr_node, dlm->node_num);
+                       status = -EINVAL;
+               }
+               goto bail;
+       }
+
+       if (o2hb_global_heartbeat_active() && !qr->qr_numregions) {
+               mlog(ML_ERROR, "Domain %s: Local node %d has global "
+                    "heartbeat enabled but joining node %d does not\n",
+                    qr->qr_domain, dlm->node_num, qr->qr_node);
+               status = -EINVAL;
+               goto bail;
+       }
+
+       r = remote;
+       for (i = 0; i < qr->qr_numregions; ++i) {
+               mlog(0, "Region %.*s\n", O2HB_MAX_REGION_NAME_LEN, r);
+               r += O2HB_MAX_REGION_NAME_LEN;
+       }
+
+       localnr = min(O2NM_MAX_REGIONS, locallen/O2HB_MAX_REGION_NAME_LEN);
+       localnr = o2hb_get_all_regions(local, (u8)localnr);
+
+       /* compare local regions with remote */
+       l = local;
+       for (i = 0; i < localnr; ++i) {
+               foundit = 0;
+               r = remote;
+               for (j = 0; j <= qr->qr_numregions; ++j) {
+                       if (!memcmp(l, r, O2HB_MAX_REGION_NAME_LEN)) {
+                               foundit = 1;
+                               break;
+                       }
+                       r += O2HB_MAX_REGION_NAME_LEN;
+               }
+               if (!foundit) {
+                       status = -EINVAL;
+                       mlog(ML_ERROR, "Domain %s: Region '%.*s' registered "
+                            "in local node %d but not in joining node %d\n",
+                            qr->qr_domain, O2HB_MAX_REGION_NAME_LEN, l,
+                            dlm->node_num, qr->qr_node);
+                       goto bail;
+               }
+               l += O2HB_MAX_REGION_NAME_LEN;
+       }
+
+       /* compare remote with local regions */
+       r = remote;
+       for (i = 0; i < qr->qr_numregions; ++i) {
+               foundit = 0;
+               l = local;
+               for (j = 0; j < localnr; ++j) {
+                       if (!memcmp(r, l, O2HB_MAX_REGION_NAME_LEN)) {
+                               foundit = 1;
+                               break;
+                       }
+                       l += O2HB_MAX_REGION_NAME_LEN;
+               }
+               if (!foundit) {
+                       status = -EINVAL;
+                       mlog(ML_ERROR, "Domain %s: Region '%.*s' registered "
+                            "in joining node %d but not in local node %d\n",
+                            qr->qr_domain, O2HB_MAX_REGION_NAME_LEN, r,
+                            qr->qr_node, dlm->node_num);
+                       goto bail;
+               }
+               r += O2HB_MAX_REGION_NAME_LEN;
+       }
+
+bail:
+       return status;
+}
+
+static int dlm_send_regions(struct dlm_ctxt *dlm, unsigned long *node_map)
+{
+       struct dlm_query_region *qr = NULL;
+       int status, ret = 0, i;
+       char *p;
+
+       if (find_next_bit(node_map, O2NM_MAX_NODES, 0) >= O2NM_MAX_NODES)
+               goto bail;
+
+       qr = kzalloc(sizeof(struct dlm_query_region), GFP_KERNEL);
+       if (!qr) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto bail;
+       }
+
+       qr->qr_node = dlm->node_num;
+       qr->qr_namelen = strlen(dlm->name);
+       memcpy(qr->qr_domain, dlm->name, qr->qr_namelen);
+       /* if local hb, the numregions will be zero */
+       if (o2hb_global_heartbeat_active())
+               qr->qr_numregions = o2hb_get_all_regions(qr->qr_regions,
+                                                        O2NM_MAX_REGIONS);
+
+       p = qr->qr_regions;
+       for (i = 0; i < qr->qr_numregions; ++i, p += O2HB_MAX_REGION_NAME_LEN)
+               mlog(0, "Region %.*s\n", O2HB_MAX_REGION_NAME_LEN, p);
+
+       i = -1;
+       while ((i = find_next_bit(node_map, O2NM_MAX_NODES,
+                                 i + 1)) < O2NM_MAX_NODES) {
+               if (i == dlm->node_num)
+                       continue;
+
+               mlog(0, "Sending regions to node %d\n", i);
+
+               ret = o2net_send_message(DLM_QUERY_REGION, DLM_MOD_KEY, qr,
+                                        sizeof(struct dlm_query_region),
+                                        i, &status);
+               if (ret >= 0)
+                       ret = status;
+               if (ret) {
+                       mlog(ML_ERROR, "Region mismatch %d, node %d\n",
+                            ret, i);
+                       break;
+               }
+       }
+
+bail:
+       kfree(qr);
+       return ret;
+}
+
+static int dlm_query_region_handler(struct o2net_msg *msg, u32 len,
+                                   void *data, void **ret_data)
+{
+       struct dlm_query_region *qr;
+       struct dlm_ctxt *dlm = NULL;
+       char *local = NULL;
+       int status = 0;
+
+       qr = (struct dlm_query_region *) msg->buf;
+
+       mlog(0, "Node %u queries hb regions on domain %s\n", qr->qr_node,
+            qr->qr_domain);
+
+       /* buffer used in dlm_mast_regions() */
+       local = kmalloc(sizeof(qr->qr_regions), GFP_KERNEL);
+       if (!local)
+               return -ENOMEM;
+
+       status = -EINVAL;
+
+       spin_lock(&dlm_domain_lock);
+       dlm = __dlm_lookup_domain_full(qr->qr_domain, qr->qr_namelen);
+       if (!dlm) {
+               mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
+                    "before join domain\n", qr->qr_node, qr->qr_domain);
+               goto out_domain_lock;
+       }
+
+       spin_lock(&dlm->spinlock);
+       if (dlm->joining_node != qr->qr_node) {
+               mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
+                    "but joining node is %d\n", qr->qr_node, qr->qr_domain,
+                    dlm->joining_node);
+               goto out_dlm_lock;
+       }
+
+       /* Support for global heartbeat was added in 1.1 */
+       if (dlm->dlm_locking_proto.pv_major == 1 &&
+           dlm->dlm_locking_proto.pv_minor == 0) {
+               mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
+                    "but active dlm protocol is %d.%d\n", qr->qr_node,
+                    qr->qr_domain, dlm->dlm_locking_proto.pv_major,
+                    dlm->dlm_locking_proto.pv_minor);
+               goto out_dlm_lock;
+       }
+
+       status = dlm_match_regions(dlm, qr, local, sizeof(qr->qr_regions));
+
+out_dlm_lock:
+       spin_unlock(&dlm->spinlock);
+
+out_domain_lock:
+       spin_unlock(&dlm_domain_lock);
+
+       kfree(local);
+
+       return status;
+}
+
+static int dlm_match_nodes(struct dlm_ctxt *dlm, struct dlm_query_nodeinfo *qn)
+{
+       struct o2nm_node *local;
+       struct dlm_node_info *remote;
+       int i, j;
+       int status = 0;
+
+       for (j = 0; j < qn->qn_numnodes; ++j)
+               mlog(0, "Node %3d, %pI4:%u\n", qn->qn_nodes[j].ni_nodenum,
+                    &(qn->qn_nodes[j].ni_ipv4_address),
+                    ntohs(qn->qn_nodes[j].ni_ipv4_port));
+
+       for (i = 0; i < O2NM_MAX_NODES && !status; ++i) {
+               local = o2nm_get_node_by_num(i);
+               remote = NULL;
+               for (j = 0; j < qn->qn_numnodes; ++j) {
+                       if (qn->qn_nodes[j].ni_nodenum == i) {
+                               remote = &(qn->qn_nodes[j]);
+                               break;
+                       }
+               }
+
+               if (!local && !remote)
+                       continue;
+
+               if ((local && !remote) || (!local && remote))
+                       status = -EINVAL;
+
+               if (!status &&
+                   ((remote->ni_nodenum != local->nd_num) ||
+                    (remote->ni_ipv4_port != local->nd_ipv4_port) ||
+                    (remote->ni_ipv4_address != local->nd_ipv4_address)))
+                       status = -EINVAL;
+
+               if (status) {
+                       if (remote && !local)
+                               mlog(ML_ERROR, "Domain %s: Node %d (%pI4:%u) "
+                                    "registered in joining node %d but not in "
+                                    "local node %d\n", qn->qn_domain,
+                                    remote->ni_nodenum,
+                                    &(remote->ni_ipv4_address),
+                                    ntohs(remote->ni_ipv4_port),
+                                    qn->qn_nodenum, dlm->node_num);
+                       if (local && !remote)
+                               mlog(ML_ERROR, "Domain %s: Node %d (%pI4:%u) "
+                                    "registered in local node %d but not in "
+                                    "joining node %d\n", qn->qn_domain,
+                                    local->nd_num, &(local->nd_ipv4_address),
+                                    ntohs(local->nd_ipv4_port),
+                                    dlm->node_num, qn->qn_nodenum);
+                       BUG_ON((!local && !remote));
+               }
+
+               if (local)
+                       o2nm_node_put(local);
+       }
+
+       return status;
+}
+
+static int dlm_send_nodeinfo(struct dlm_ctxt *dlm, unsigned long *node_map)
+{
+       struct dlm_query_nodeinfo *qn = NULL;
+       struct o2nm_node *node;
+       int ret = 0, status, count, i;
+
+       if (find_next_bit(node_map, O2NM_MAX_NODES, 0) >= O2NM_MAX_NODES)
+               goto bail;
+
+       qn = kzalloc(sizeof(struct dlm_query_nodeinfo), GFP_KERNEL);
+       if (!qn) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto bail;
+       }
+
+       for (i = 0, count = 0; i < O2NM_MAX_NODES; ++i) {
+               node = o2nm_get_node_by_num(i);
+               if (!node)
+                       continue;
+               qn->qn_nodes[count].ni_nodenum = node->nd_num;
+               qn->qn_nodes[count].ni_ipv4_port = node->nd_ipv4_port;
+               qn->qn_nodes[count].ni_ipv4_address = node->nd_ipv4_address;
+               mlog(0, "Node %3d, %pI4:%u\n", node->nd_num,
+                    &(node->nd_ipv4_address), ntohs(node->nd_ipv4_port));
+               ++count;
+               o2nm_node_put(node);
+       }
+
+       qn->qn_nodenum = dlm->node_num;
+       qn->qn_numnodes = count;
+       qn->qn_namelen = strlen(dlm->name);
+       memcpy(qn->qn_domain, dlm->name, qn->qn_namelen);
+
+       i = -1;
+       while ((i = find_next_bit(node_map, O2NM_MAX_NODES,
+                                 i + 1)) < O2NM_MAX_NODES) {
+               if (i == dlm->node_num)
+                       continue;
+
+               mlog(0, "Sending nodeinfo to node %d\n", i);
+
+               ret = o2net_send_message(DLM_QUERY_NODEINFO, DLM_MOD_KEY,
+                                        qn, sizeof(struct dlm_query_nodeinfo),
+                                        i, &status);
+               if (ret >= 0)
+                       ret = status;
+               if (ret) {
+                       mlog(ML_ERROR, "node mismatch %d, node %d\n", ret, i);
+                       break;
+               }
+       }
+
+bail:
+       kfree(qn);
+       return ret;
+}
+
+static int dlm_query_nodeinfo_handler(struct o2net_msg *msg, u32 len,
+                                     void *data, void **ret_data)
+{
+       struct dlm_query_nodeinfo *qn;
+       struct dlm_ctxt *dlm = NULL;
+       int locked = 0, status = -EINVAL;
+
+       qn = (struct dlm_query_nodeinfo *) msg->buf;
+
+       mlog(0, "Node %u queries nodes on domain %s\n", qn->qn_nodenum,
+            qn->qn_domain);
+
+       spin_lock(&dlm_domain_lock);
+       dlm = __dlm_lookup_domain_full(qn->qn_domain, qn->qn_namelen);
+       if (!dlm) {
+               mlog(ML_ERROR, "Node %d queried nodes on domain %s before "
+                    "join domain\n", qn->qn_nodenum, qn->qn_domain);
+               goto bail;
+       }
+
+       spin_lock(&dlm->spinlock);
+       locked = 1;
+       if (dlm->joining_node != qn->qn_nodenum) {
+               mlog(ML_ERROR, "Node %d queried nodes on domain %s but "
+                    "joining node is %d\n", qn->qn_nodenum, qn->qn_domain,
+                    dlm->joining_node);
+               goto bail;
+       }
+
+       /* Support for node query was added in 1.1 */
+       if (dlm->dlm_locking_proto.pv_major == 1 &&
+           dlm->dlm_locking_proto.pv_minor == 0) {
+               mlog(ML_ERROR, "Node %d queried nodes on domain %s "
+                    "but active dlm protocol is %d.%d\n", qn->qn_nodenum,
+                    qn->qn_domain, dlm->dlm_locking_proto.pv_major,
+                    dlm->dlm_locking_proto.pv_minor);
+               goto bail;
+       }
+
+       status = dlm_match_nodes(dlm, qn);
+
+bail:
+       if (locked)
+               spin_unlock(&dlm->spinlock);
+       spin_unlock(&dlm_domain_lock);
+
+       return status;
+}
+
+static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
+                                  void **ret_data)
+{
+       struct dlm_cancel_join *cancel;
+       struct dlm_ctxt *dlm = NULL;
+
+       cancel = (struct dlm_cancel_join *) msg->buf;
+
+       mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
+                 cancel->domain);
+
+       spin_lock(&dlm_domain_lock);
+       dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
+
+       if (dlm) {
+               spin_lock(&dlm->spinlock);
+
+               /* Yikes, this guy wants to cancel his join. No
+                * problem, we simply cleanup our join state. */
+               BUG_ON(dlm->joining_node != cancel->node_idx);
+               __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
+
+               spin_unlock(&dlm->spinlock);
+       }
+       spin_unlock(&dlm_domain_lock);
+
+       return 0;
+}
+
+static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
+                                   unsigned int node)
+{
+       int status;
+       struct dlm_cancel_join cancel_msg;
+
+       memset(&cancel_msg, 0, sizeof(cancel_msg));
+       cancel_msg.node_idx = dlm->node_num;
+       cancel_msg.name_len = strlen(dlm->name);
+       memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
+
+       status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
+                                   &cancel_msg, sizeof(cancel_msg), node,
+                                   NULL);
+       if (status < 0) {
+               mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
+                    "node %u\n", status, DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
+                    node);
+               goto bail;
+       }
+
+bail:
+       return status;
+}
+
+/* map_size should be in bytes. */
+static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
+                                unsigned long *node_map,
+                                unsigned int map_size)
+{
+       int status, tmpstat;
+       unsigned int node;
+
+       if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
+                        sizeof(unsigned long))) {
+               mlog(ML_ERROR,
+                    "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
+                    map_size, (unsigned)BITS_TO_LONGS(O2NM_MAX_NODES));
+               return -EINVAL;
+       }
+
+       status = 0;
+       node = -1;
+       while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
+                                    node + 1)) < O2NM_MAX_NODES) {
+               if (node == dlm->node_num)
+                       continue;
+
+               tmpstat = dlm_send_one_join_cancel(dlm, node);
+               if (tmpstat) {
+                       mlog(ML_ERROR, "Error return %d cancelling join on "
+                            "node %d\n", tmpstat, node);
+                       if (!status)
+                               status = tmpstat;
+               }
+       }
+
+       if (status)
+               mlog_errno(status);
+       return status;
+}
+
+static int dlm_request_join(struct dlm_ctxt *dlm,
+                           int node,
+                           enum dlm_query_join_response_code *response)
+{
+       int status;
+       struct dlm_query_join_request join_msg;
+       struct dlm_query_join_packet packet;
+       u32 join_resp;
+
+       mlog(0, "querying node %d\n", node);
+
+       memset(&join_msg, 0, sizeof(join_msg));
+       join_msg.node_idx = dlm->node_num;
+       join_msg.name_len = strlen(dlm->name);
+       memcpy(join_msg.domain, dlm->name, join_msg.name_len);
+       join_msg.dlm_proto = dlm->dlm_locking_proto;
+       join_msg.fs_proto = dlm->fs_locking_proto;
+
+       /* copy live node map to join message */
+       byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
+
+       status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
+                                   sizeof(join_msg), node, &join_resp);
+       if (status < 0 && status != -ENOPROTOOPT) {
+               mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
+                    "node %u\n", status, DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
+                    node);
+               goto bail;
+       }
+       dlm_query_join_wire_to_packet(join_resp, &packet);
+
+       /* -ENOPROTOOPT from the net code means the other side isn't
+           listening for our message type -- that's fine, it means
+           his dlm isn't up, so we can consider him a 'yes' but not
+           joined into the domain.  */
+       if (status == -ENOPROTOOPT) {
+               status = 0;
+               *response = JOIN_OK_NO_MAP;
+       } else if (packet.code == JOIN_DISALLOW ||
+                  packet.code == JOIN_OK_NO_MAP) {
+               *response = packet.code;
+       } else if (packet.code == JOIN_PROTOCOL_MISMATCH) {
+               mlog(ML_NOTICE,
+                    "This node requested DLM locking protocol %u.%u and "
+                    "filesystem locking protocol %u.%u.  At least one of "
+                    "the protocol versions on node %d is not compatible, "
+                    "disconnecting\n",
+                    dlm->dlm_locking_proto.pv_major,
+                    dlm->dlm_locking_proto.pv_minor,
+                    dlm->fs_locking_proto.pv_major,
+                    dlm->fs_locking_proto.pv_minor,
+                    node);
+               status = -EPROTO;
+               *response = packet.code;
+       } else if (packet.code == JOIN_OK) {
+               *response = packet.code;
+               /* Use the same locking protocol as the remote node */
+               dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
+               dlm->fs_locking_proto.pv_minor = packet.fs_minor;
+               mlog(0,
+                    "Node %d responds JOIN_OK with DLM locking protocol "
+                    "%u.%u and fs locking protocol %u.%u\n",
+                    node,
+                    dlm->dlm_locking_proto.pv_major,
+                    dlm->dlm_locking_proto.pv_minor,
+                    dlm->fs_locking_proto.pv_major,
+                    dlm->fs_locking_proto.pv_minor);
+       } else {
+               status = -EINVAL;
+               mlog(ML_ERROR, "invalid response %d from node %u\n",
+                    packet.code, node);
+       }
+
+       mlog(0, "status %d, node %d response is %d\n", status, node,
+            *response);
+
+bail:
+       return status;
+}
+
+static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
+                                   unsigned int node)
+{
+       int status;
+       int ret;
+       struct dlm_assert_joined assert_msg;
+
+       mlog(0, "Sending join assert to node %u\n", node);
+
+       memset(&assert_msg, 0, sizeof(assert_msg));
+       assert_msg.node_idx = dlm->node_num;
+       assert_msg.name_len = strlen(dlm->name);
+       memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
+
+       status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
+                                   &assert_msg, sizeof(assert_msg), node,
+                                   &ret);
+       if (status < 0)
+               mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
+                    "node %u\n", status, DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
+                    node);
+       else
+               status = ret;
+
+       return status;
+}
+
+static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
+                                 unsigned long *node_map)
+{
+       int status, node, live;
+
+       status = 0;
+       node = -1;
+       while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
+                                    node + 1)) < O2NM_MAX_NODES) {
+               if (node == dlm->node_num)
+                       continue;
+
+               do {
+                       /* It is very important that this message be
+                        * received so we spin until either the node
+                        * has died or it gets the message. */
+                       status = dlm_send_one_join_assert(dlm, node);
+
+                       spin_lock(&dlm->spinlock);
+                       live = test_bit(node, dlm->live_nodes_map);
+                       spin_unlock(&dlm->spinlock);
+
+                       if (status) {
+                               mlog(ML_ERROR, "Error return %d asserting "
+                                    "join on node %d\n", status, node);
+
+                               /* give us some time between errors... */
+                               if (live)
+                                       msleep(DLM_DOMAIN_BACKOFF_MS);
+                       }
+               } while (status && live);
+       }
+}
+
+struct domain_join_ctxt {
+       unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
+       unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
+};
+
+static int dlm_should_restart_join(struct dlm_ctxt *dlm,
+                                  struct domain_join_ctxt *ctxt,
+                                  enum dlm_query_join_response_code response)
+{
+       int ret;
+
+       if (response == JOIN_DISALLOW) {
+               mlog(0, "Latest response of disallow -- should restart\n");
+               return 1;
+       }
+
+       spin_lock(&dlm->spinlock);
+       /* For now, we restart the process if the node maps have
+        * changed at all */
+       ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
+                    sizeof(dlm->live_nodes_map));
+       spin_unlock(&dlm->spinlock);
+
+       if (ret)
+               mlog(0, "Node maps changed -- should restart\n");
+
+       return ret;
+}
+
+static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
+{
+       int status = 0, tmpstat, node;
+       struct domain_join_ctxt *ctxt;
+       enum dlm_query_join_response_code response = JOIN_DISALLOW;
+
+       mlog(0, "%p", dlm);
+
+       ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
+       if (!ctxt) {
+               status = -ENOMEM;
+               mlog_errno(status);
+               goto bail;
+       }
+
+       /* group sem locking should work for us here -- we're already
+        * registered for heartbeat events so filling this should be
+        * atomic wrt getting those handlers called. */
+       o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
+
+       spin_lock(&dlm->spinlock);
+       memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
+
+       __dlm_set_joining_node(dlm, dlm->node_num);
+
+       spin_unlock(&dlm->spinlock);
+
+       node = -1;
+       while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
+                                    node + 1)) < O2NM_MAX_NODES) {
+               if (node == dlm->node_num)
+                       continue;
+
+               status = dlm_request_join(dlm, node, &response);
+               if (status < 0) {
+                       mlog_errno(status);
+                       goto bail;
+               }
+
+               /* Ok, either we got a response or the node doesn't have a
+                * dlm up. */
+               if (response == JOIN_OK)
+                       set_bit(node, ctxt->yes_resp_map);
+
+               if (dlm_should_restart_join(dlm, ctxt, response)) {
+                       status = -EAGAIN;
+                       goto bail;
+               }
+       }
+
+       mlog(0, "Yay, done querying nodes!\n");
+
+       /* Yay, everyone agree's we can join the domain. My domain is
+        * comprised of all nodes who were put in the
+        * yes_resp_map. Copy that into our domain map and send a join
+        * assert message to clean up everyone elses state. */
+       spin_lock(&dlm->spinlock);
+       memcpy(dlm->domain_map, ctxt->yes_resp_map,
+              sizeof(ctxt->yes_resp_map));
+       set_bit(dlm->node_num, dlm->domain_map);
+       spin_unlock(&dlm->spinlock);
+
+       /* Support for global heartbeat and node info was added in 1.1 */
+       if (dlm->dlm_locking_proto.pv_major > 1 ||
+           dlm->dlm_locking_proto.pv_minor > 0) {
+               status = dlm_send_nodeinfo(dlm, ctxt->yes_resp_map);
+               if (status) {
+                       mlog_errno(status);
+                       goto bail;
+               }
+               status = dlm_send_regions(dlm, ctxt->yes_resp_map);
+               if (status) {
+                       mlog_errno(status);
+                       goto bail;
+               }
+       }
+
+       dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
+
+       /* Joined state *must* be set before the joining node
+        * information, otherwise the query_join handler may read no
+        * current joiner but a state of NEW and tell joining nodes
+        * we're not in the domain. */
+       spin_lock(&dlm_domain_lock);
+       dlm->dlm_state = DLM_CTXT_JOINED;
+       dlm->num_joins++;
+       spin_unlock(&dlm_domain_lock);
+
+bail:
+       spin_lock(&dlm->spinlock);
+       __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
+       if (!status) {
+               printk(KERN_NOTICE "o2dlm: Joining domain %s ", dlm->name);
+               __dlm_print_nodes(dlm);
+       }
+       spin_unlock(&dlm->spinlock);
+
+       if (ctxt) {
+               /* Do we need to send a cancel message to any nodes? */
+               if (status < 0) {
+                       tmpstat = dlm_send_join_cancels(dlm,
+                                                       ctxt->yes_resp_map,
+                                                       sizeof(ctxt->yes_resp_map));
+                       if (tmpstat < 0)
+                               mlog_errno(tmpstat);
+               }
+               kfree(ctxt);
+       }
+
+       mlog(0, "returning %d\n", status);
+       return status;
+}
+
+static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
+{
+       o2hb_unregister_callback(dlm->name, &dlm->dlm_hb_up);
+       o2hb_unregister_callback(dlm->name, &dlm->dlm_hb_down);
+       o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
+}
+
+static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
+{
+       int status;
+
+       mlog(0, "registering handlers.\n");
+
+       o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
+                           dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
+       status = o2hb_register_callback(dlm->name, &dlm->dlm_hb_down);
+       if (status)
+               goto bail;
+
+       o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
+                           dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
+       status = o2hb_register_callback(dlm->name, &dlm->dlm_hb_up);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
+                                       sizeof(struct dlm_master_request),
+                                       dlm_master_request_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
+                                       sizeof(struct dlm_assert_master),
+                                       dlm_assert_master_handler,
+                                       dlm, dlm_assert_master_post_handler,
+                                       &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
+                                       sizeof(struct dlm_create_lock),
+                                       dlm_create_lock_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
+                                       DLM_CONVERT_LOCK_MAX_LEN,
+                                       dlm_convert_lock_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
+                                       DLM_UNLOCK_LOCK_MAX_LEN,
+                                       dlm_unlock_lock_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
+                                       DLM_PROXY_AST_MAX_LEN,
+                                       dlm_proxy_ast_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
+                                       sizeof(struct dlm_exit_domain),
+                                       dlm_exit_domain_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
+                                       sizeof(struct dlm_deref_lockres),
+                                       dlm_deref_lockres_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
+                                       sizeof(struct dlm_migrate_request),
+                                       dlm_migrate_request_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
+                                       DLM_MIG_LOCKRES_MAX_LEN,
+                                       dlm_mig_lockres_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
+                                       sizeof(struct dlm_master_requery),
+                                       dlm_master_requery_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
+                                       sizeof(struct dlm_lock_request),
+                                       dlm_request_all_locks_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
+                                       sizeof(struct dlm_reco_data_done),
+                                       dlm_reco_data_done_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
+                                       sizeof(struct dlm_begin_reco),
+                                       dlm_begin_reco_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
+                                       sizeof(struct dlm_finalize_reco),
+                                       dlm_finalize_reco_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_BEGIN_EXIT_DOMAIN_MSG, dlm->key,
+                                       sizeof(struct dlm_exit_domain),
+                                       dlm_begin_exit_domain_handler,
+                                       dlm, NULL, &dlm->dlm_domain_handlers);
+       if (status)
+               goto bail;
+
+bail:
+       if (status)
+               dlm_unregister_domain_handlers(dlm);
+
+       return status;
+}
+
+static int dlm_join_domain(struct dlm_ctxt *dlm)
+{
+       int status;
+       unsigned int backoff;
+       unsigned int total_backoff = 0;
+
+       BUG_ON(!dlm);
+
+       mlog(0, "Join domain %s\n", dlm->name);
+
+       status = dlm_register_domain_handlers(dlm);
+       if (status) {
+               mlog_errno(status);
+               goto bail;
+       }
+
+       status = dlm_launch_thread(dlm);
+       if (status < 0) {
+               mlog_errno(status);
+               goto bail;
+       }
+
+       status = dlm_launch_recovery_thread(dlm);
+       if (status < 0) {
+               mlog_errno(status);
+               goto bail;
+       }
+
+       status = dlm_debug_init(dlm);
+       if (status < 0) {
+               mlog_errno(status);
+               goto bail;
+       }
+
+       dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
+       if (!dlm->dlm_worker) {
+               status = -ENOMEM;
+               mlog_errno(status);
+               goto bail;
+       }
+
+       do {
+               status = dlm_try_to_join_domain(dlm);
+
+               /* If we're racing another node to the join, then we
+                * need to back off temporarily and let them
+                * complete. */
+#define        DLM_JOIN_TIMEOUT_MSECS  90000
+               if (status == -EAGAIN) {
+                       if (signal_pending(current)) {
+                               status = -ERESTARTSYS;
+                               goto bail;
+                       }
+
+                       if (total_backoff > DLM_JOIN_TIMEOUT_MSECS) {
+                               status = -ERESTARTSYS;
+                               mlog(ML_NOTICE, "Timed out joining dlm domain "
+                                    "%s after %u msecs\n", dlm->name,
+                                    total_backoff);
+                               goto bail;
+                       }
+
+                       /*
+                        * <chip> After you!
+                        * <dale> No, after you!
+                        * <chip> I insist!
+                        * <dale> But you first!
+                        * ...
+                        */
+                       backoff = (unsigned int)(jiffies & 0x3);
+                       backoff *= DLM_DOMAIN_BACKOFF_MS;
+                       total_backoff += backoff;
+                       mlog(0, "backoff %d\n", backoff);
+                       msleep(backoff);
+               }
+       } while (status == -EAGAIN);
+
+       if (status < 0) {
+               mlog_errno(status);
+               goto bail;
+       }
+
+       status = 0;
+bail:
+       wake_up(&dlm_domain_events);
+
+       if (status) {
+               dlm_unregister_domain_handlers(dlm);
+               dlm_debug_shutdown(dlm);
+               dlm_complete_thread(dlm);
+               dlm_complete_recovery_thread(dlm);
+               dlm_destroy_dlm_worker(dlm);
+       }
+
+       return status;
+}
+
+static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
+                               u32 key)
+{
+       int i;
+       int ret;
+       struct dlm_ctxt *dlm = NULL;
+
+       dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
+       if (!dlm) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto leave;
+       }
+
+       dlm->name = kstrdup(domain, GFP_KERNEL);
+       if (dlm->name == NULL) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto leave;
+       }
+
+       dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
+       if (!dlm->lockres_hash) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto leave;
+       }
+
+       for (i = 0; i < DLM_HASH_BUCKETS; i++)
+               INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
+
+       dlm->master_hash = (struct hlist_head **)
+                               dlm_alloc_pagevec(DLM_HASH_PAGES);
+       if (!dlm->master_hash) {
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto leave;
+       }
+
+       for (i = 0; i < DLM_HASH_BUCKETS; i++)
+               INIT_HLIST_HEAD(dlm_master_hash(dlm, i));
+
+       dlm->key = key;
+       dlm->node_num = o2nm_this_node();
+
+       ret = dlm_create_debugfs_subroot(dlm);
+       if (ret < 0)
+               goto leave;
+
+       spin_lock_init(&dlm->spinlock);
+       spin_lock_init(&dlm->master_lock);
+       spin_lock_init(&dlm->ast_lock);
+       spin_lock_init(&dlm->track_lock);
+       INIT_LIST_HEAD(&dlm->list);
+       INIT_LIST_HEAD(&dlm->dirty_list);
+       INIT_LIST_HEAD(&dlm->reco.resources);
+       INIT_LIST_HEAD(&dlm->reco.node_data);
+       INIT_LIST_HEAD(&dlm->purge_list);
+       INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
+       INIT_LIST_HEAD(&dlm->tracking_list);
+       dlm->reco.state = 0;
+
+       INIT_LIST_HEAD(&dlm->pending_asts);
+       INIT_LIST_HEAD(&dlm->pending_basts);
+
+       mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
+                 dlm->recovery_map, &(dlm->recovery_map[0]));
+
+       memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
+       memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
+       memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
+
+       dlm->dlm_thread_task = NULL;
+       dlm->dlm_reco_thread_task = NULL;
+       dlm->dlm_worker = NULL;
+       init_waitqueue_head(&dlm->dlm_thread_wq);
+       init_waitqueue_head(&dlm->dlm_reco_thread_wq);
+       init_waitqueue_head(&dlm->reco.event);
+       init_waitqueue_head(&dlm->ast_wq);
+       init_waitqueue_head(&dlm->migration_wq);
+       INIT_LIST_HEAD(&dlm->mle_hb_events);
+
+       dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
+       init_waitqueue_head(&dlm->dlm_join_events);
+
+       dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
+       dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
+
+       atomic_set(&dlm->res_tot_count, 0);
+       atomic_set(&dlm->res_cur_count, 0);
+       for (i = 0; i < DLM_MLE_NUM_TYPES; ++i) {
+               atomic_set(&dlm->mle_tot_count[i], 0);
+               atomic_set(&dlm->mle_cur_count[i], 0);
+       }
+
+       spin_lock_init(&dlm->work_lock);
+       INIT_LIST_HEAD(&dlm->work_list);
+       INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
+
+       kref_init(&dlm->dlm_refs);
+       dlm->dlm_state = DLM_CTXT_NEW;
+
+       INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
+
+       mlog(0, "context init: refcount %u\n",
+                 atomic_read(&dlm->dlm_refs.refcount));
+
+leave:
+       if (ret < 0 && dlm) {
+               if (dlm->master_hash)
+                       dlm_free_pagevec((void **)dlm->master_hash,
+                                       DLM_HASH_PAGES);
+
+               if (dlm->lockres_hash)
+                       dlm_free_pagevec((void **)dlm->lockres_hash,
+                                       DLM_HASH_PAGES);
+
+               kfree(dlm->name);
+               kfree(dlm);
+               dlm = NULL;
+       }
+       return dlm;
+}
+
+/*
+ * Compare a requested locking protocol version against the current one.
+ *
+ * If the major numbers are different, they are incompatible.
+ * If the current minor is greater than the request, they are incompatible.
+ * If the current minor is less than or equal to the request, they are
+ * compatible, and the requester should run at the current minor version.
+ */
+static int dlm_protocol_compare(struct dlm_protocol_version *existing,
+                               struct dlm_protocol_version *request)
+{
+       if (existing->pv_major != request->pv_major)
+               return 1;
+
+       if (existing->pv_minor > request->pv_minor)
+               return 1;
+
+       if (existing->pv_minor < request->pv_minor)
+               request->pv_minor = existing->pv_minor;
+
+       return 0;
+}
+
+/*
+ * dlm_register_domain: one-time setup per "domain".
+ *
+ * The filesystem passes in the requested locking version via proto.
+ * If registration was successful, proto will contain the negotiated
+ * locking protocol.
+ */
+struct dlm_ctxt * dlm_register_domain(const char *domain,
+                              u32 key,
+                              struct dlm_protocol_version *fs_proto)
+{
+       int ret;
+       struct dlm_ctxt *dlm = NULL;
+       struct dlm_ctxt *new_ctxt = NULL;
+
+       if (strlen(domain) >= O2NM_MAX_NAME_LEN) {
+               ret = -ENAMETOOLONG;
+               mlog(ML_ERROR, "domain name length too long\n");
+               goto leave;
+       }
+
+       mlog(0, "register called for domain \"%s\"\n", domain);
+
+retry:
+       dlm = NULL;
+       if (signal_pending(current)) {
+               ret = -ERESTARTSYS;
+               mlog_errno(ret);
+               goto leave;
+       }
+
+       spin_lock(&dlm_domain_lock);
+
+       dlm = __dlm_lookup_domain(domain);
+       if (dlm) {
+               if (dlm->dlm_state != DLM_CTXT_JOINED) {
+                       spin_unlock(&dlm_domain_lock);
+
+                       mlog(0, "This ctxt is not joined yet!\n");
+                       wait_event_interruptible(dlm_domain_events,
+                                                dlm_wait_on_domain_helper(
+                                                        domain));
+                       goto retry;
+               }
+
+               if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
+                       spin_unlock(&dlm_domain_lock);
+                       mlog(ML_ERROR,
+                            "Requested locking protocol version is not "
+                            "compatible with already registered domain "
+                            "\"%s\"\n", domain);
+                       ret = -EPROTO;
+                       goto leave;
+               }
+
+               __dlm_get(dlm);
+               dlm->num_joins++;
+
+               spin_unlock(&dlm_domain_lock);
+
+               ret = 0;
+               goto leave;
+       }
+
+       /* doesn't exist */
+       if (!new_ctxt) {
+               spin_unlock(&dlm_domain_lock);
+
+               new_ctxt = dlm_alloc_ctxt(domain, key);
+               if (new_ctxt)
+                       goto retry;
+
+               ret = -ENOMEM;
+               mlog_errno(ret);
+               goto leave;
+       }
+
+       /* a little variable switch-a-roo here... */
+       dlm = new_ctxt;
+       new_ctxt = NULL;
+
+       /* add the new domain */
+       list_add_tail(&dlm->list, &dlm_domains);
+       spin_unlock(&dlm_domain_lock);
+
+       /*
+        * Pass the locking protocol version into the join.  If the join
+        * succeeds, it will have the negotiated protocol set.
+        */
+       dlm->dlm_locking_proto = dlm_protocol;
+       dlm->fs_locking_proto = *fs_proto;
+
+       ret = dlm_join_domain(dlm);
+       if (ret) {
+               mlog_errno(ret);
+               dlm_put(dlm);
+               goto leave;
+       }
+
+       /* Tell the caller what locking protocol we negotiated */
+       *fs_proto = dlm->fs_locking_proto;
+
+       ret = 0;
+leave:
+       if (new_ctxt)
+               dlm_free_ctxt_mem(new_ctxt);
+
+       if (ret < 0)
+               dlm = ERR_PTR(ret);
+
+       return dlm;
+}
+EXPORT_SYMBOL_GPL(dlm_register_domain);
+
+static LIST_HEAD(dlm_join_handlers);
+
+static void dlm_unregister_net_handlers(void)
+{
+       o2net_unregister_handler_list(&dlm_join_handlers);
+}
+
+static int dlm_register_net_handlers(void)
+{
+       int status = 0;
+
+       status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
+                                       sizeof(struct dlm_query_join_request),
+                                       dlm_query_join_handler,
+                                       NULL, NULL, &dlm_join_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
+                                       sizeof(struct dlm_assert_joined),
+                                       dlm_assert_joined_handler,
+                                       NULL, NULL, &dlm_join_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
+                                       sizeof(struct dlm_cancel_join),
+                                       dlm_cancel_join_handler,
+                                       NULL, NULL, &dlm_join_handlers);
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_QUERY_REGION, DLM_MOD_KEY,
+                                       sizeof(struct dlm_query_region),
+                                       dlm_query_region_handler,
+                                       NULL, NULL, &dlm_join_handlers);
+
+       if (status)
+               goto bail;
+
+       status = o2net_register_handler(DLM_QUERY_NODEINFO, DLM_MOD_KEY,
+                                       sizeof(struct dlm_query_nodeinfo),
+                                       dlm_query_nodeinfo_handler,
+                                       NULL, NULL, &dlm_join_handlers);
+bail:
+       if (status < 0)
+               dlm_unregister_net_handlers();
+
+       return status;
+}
+
+/* Domain eviction callback handling.
+ *
+ * The file system requires notification of node death *before* the
+ * dlm completes it's recovery work, otherwise it may be able to
+ * acquire locks on resources requiring recovery. Since the dlm can
+ * evict a node from it's domain *before* heartbeat fires, a similar
+ * mechanism is required. */
+
+/* Eviction is not expected to happen often, so a per-domain lock is
+ * not necessary. Eviction callbacks are allowed to sleep for short
+ * periods of time. */
+static DECLARE_RWSEM(dlm_callback_sem);
+
+void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
+                                       int node_num)
+{
+       struct dlm_eviction_cb *cb;
+
+       down_read(&dlm_callback_sem);
+       list_for_each_entry(cb, &dlm->dlm_eviction_callbacks, ec_item) {
+               cb->ec_func(node_num, cb->ec_data);
+       }
+       up_read(&dlm_callback_sem);
+}
+
+void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
+                          dlm_eviction_func *f,
+                          void *data)
+{
+       INIT_LIST_HEAD(&cb->ec_item);
+       cb->ec_func = f;
+       cb->ec_data = data;
+}
+EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
+
+void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
+                             struct dlm_eviction_cb *cb)
+{
+       down_write(&dlm_callback_sem);
+       list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
+       up_write(&dlm_callback_sem);
+}
+EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
+
+void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
+{
+       down_write(&dlm_callback_sem);
+       list_del_init(&cb->ec_item);
+       up_write(&dlm_callback_sem);
+}
+EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
+
+static int __init dlm_init(void)
+{
+       int status;
+
+       status = dlm_init_mle_cache();
+       if (status) {
+               mlog(ML_ERROR, "Could not create o2dlm_mle slabcache\n");
+               goto error;
+       }
+
+       status = dlm_init_master_caches();
+       if (status) {
+               mlog(ML_ERROR, "Could not create o2dlm_lockres and "
+                    "o2dlm_lockname slabcaches\n");
+               goto error;
+       }
+
+       status = dlm_init_lock_cache();
+       if (status) {
+               mlog(ML_ERROR, "Count not create o2dlm_lock slabcache\n");
+               goto error;
+       }
+
+       status = dlm_register_net_handlers();
+       if (status) {
+               mlog(ML_ERROR, "Unable to register network handlers\n");
+               goto error;
+       }
+
+       status = dlm_create_debugfs_root();
+       if (status)
+               goto error;
+
+       return 0;
+error:
+       dlm_unregister_net_handlers();
+       dlm_destroy_lock_cache();
+       dlm_destroy_master_caches();
+       dlm_destroy_mle_cache();
+       return -1;
+}
+
+static void __exit dlm_exit (void)
+{
+       dlm_destroy_debugfs_root();
+       dlm_unregister_net_handlers();
+       dlm_destroy_lock_cache();
+       dlm_destroy_master_caches();
+       dlm_destroy_mle_cache();
+}
+
+MODULE_AUTHOR("Oracle");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("OCFS2 Distributed Lock Management");
+
+module_init(dlm_init);
+module_exit(dlm_exit);