[PATCH] OCFS2: The Second Oracle Cluster Filesystem
A distributed lock manager built with the cluster file system use case
in mind. The OCFS2 dlm exposes a VMS style API, though things have
been simplified internally. The only lock levels implemented currently
are NLMODE, PRMODE and EXMODE.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Kurt Hackel <kurt.hackel@oracle.com>
diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
new file mode 100644
index 0000000..da3c220
--- /dev/null
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -0,0 +1,1469 @@
+/* -*- 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/utsname.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+
+#include "cluster/heartbeat.h"
+#include "cluster/nodemanager.h"
+#include "cluster/tcp.h"
+
+#include "dlmapi.h"
+#include "dlmcommon.h"
+
+#include "dlmdebug.h"
+#include "dlmdomain.h"
+
+#include "dlmver.h"
+
+#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
+#include "cluster/masklog.h"
+
+/*
+ *
+ * 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
+ *
+ */
+
+spinlock_t dlm_domain_lock = SPIN_LOCK_UNLOCKED;
+LIST_HEAD(dlm_domains);
+static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
+
+#define DLM_DOMAIN_BACKOFF_MS 200
+
+static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data);
+static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data);
+static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data);
+static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data);
+
+static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
+
+void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
+{
+ list_del_init(&lockres->list);
+ dlm_lockres_put(lockres);
+}
+
+void __dlm_insert_lockres(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res)
+{
+ struct list_head *bucket;
+ struct qstr *q;
+
+ assert_spin_locked(&dlm->spinlock);
+
+ q = &res->lockname;
+ q->hash = full_name_hash(q->name, q->len);
+ bucket = &(dlm->resources[q->hash & DLM_HASH_MASK]);
+
+ /* get a reference for our hashtable */
+ dlm_lockres_get(res);
+
+ list_add_tail(&res->list, bucket);
+}
+
+struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
+ const char *name,
+ unsigned int len)
+{
+ unsigned int hash;
+ struct list_head *iter;
+ struct dlm_lock_resource *tmpres=NULL;
+ struct list_head *bucket;
+
+ mlog_entry("%.*s\n", len, name);
+
+ assert_spin_locked(&dlm->spinlock);
+
+ hash = full_name_hash(name, len);
+
+ bucket = &(dlm->resources[hash & DLM_HASH_MASK]);
+
+ /* check for pre-existing lock */
+ list_for_each(iter, bucket) {
+ tmpres = list_entry(iter, struct dlm_lock_resource, list);
+ if (tmpres->lockname.len == len &&
+ memcmp(tmpres->lockname.name, name, len) == 0) {
+ dlm_lockres_get(tmpres);
+ break;
+ }
+
+ tmpres = NULL;
+ }
+ return tmpres;
+}
+
+struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
+ const char *name,
+ unsigned int len)
+{
+ struct dlm_lock_resource *res;
+
+ spin_lock(&dlm->spinlock);
+ res = __dlm_lookup_lockres(dlm, name, len);
+ spin_unlock(&dlm->spinlock);
+ return res;
+}
+
+static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
+{
+ struct dlm_ctxt *tmp = NULL;
+ struct list_head *iter;
+
+ assert_spin_locked(&dlm_domain_lock);
+
+ /* tmp->name here is always NULL terminated,
+ * but domain may not be! */
+ list_for_each(iter, &dlm_domains) {
+ tmp = list_entry (iter, struct dlm_ctxt, list);
+ if (strlen(tmp->name) == len &&
+ memcmp(tmp->name, domain, len)==0)
+ break;
+ tmp = NULL;
+ }
+
+ return tmp;
+}
+
+/* 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)
+{
+ if (dlm->resources)
+ free_page((unsigned long) dlm->resources);
+
+ if (dlm->name)
+ 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 list_head *iter;
+ struct dlm_ctxt *target = NULL;
+
+ spin_lock(&dlm_domain_lock);
+
+ list_for_each(iter, &dlm_domains) {
+ target = list_entry (iter, struct dlm_ctxt, list);
+
+ if (target == dlm) {
+ __dlm_get(target);
+ break;
+ }
+
+ target = NULL;
+ }
+
+ spin_unlock(&dlm_domain_lock);
+
+ return target;
+}
+
+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_complete_dlm_shutdown(struct dlm_ctxt *dlm)
+{
+ dlm_unregister_domain_handlers(dlm);
+ dlm_complete_thread(dlm);
+ dlm_complete_recovery_thread(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 void dlm_migrate_all_locks(struct dlm_ctxt *dlm)
+{
+ int i;
+ struct dlm_lock_resource *res;
+
+ mlog(0, "Migrating locks from domain %s\n", dlm->name);
+restart:
+ spin_lock(&dlm->spinlock);
+ for (i=0; i<DLM_HASH_SIZE; i++) {
+ while (!list_empty(&dlm->resources[i])) {
+ res = list_entry(dlm->resources[i].next,
+ struct dlm_lock_resource, list);
+ /* need reference when manually grabbing lockres */
+ dlm_lockres_get(res);
+ /* this should unhash the lockres
+ * and exit with dlm->spinlock */
+ mlog(0, "purging res=%p\n", res);
+ if (dlm_lockres_is_dirty(dlm, res)) {
+ /* HACK! this should absolutely go.
+ * need to figure out why some empty
+ * lockreses are still marked dirty */
+ mlog(ML_ERROR, "lockres %.*s dirty!\n",
+ res->lockname.len, res->lockname.name);
+
+ spin_unlock(&dlm->spinlock);
+ dlm_kick_thread(dlm, res);
+ wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
+ dlm_lockres_put(res);
+ goto restart;
+ }
+ dlm_purge_lockres(dlm, res);
+ dlm_lockres_put(res);
+ }
+ }
+ spin_unlock(&dlm->spinlock);
+
+ mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
+}
+
+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 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;
+
+ assert_spin_locked(&dlm->spinlock);
+
+ mlog(ML_NOTICE, "Nodes in my domain (\"%s\"):\n", dlm->name);
+
+ while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
+ node + 1)) < O2NM_MAX_NODES) {
+ mlog(ML_NOTICE, " node %d\n", node);
+ }
+}
+
+static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+ struct dlm_ctxt *dlm = data;
+ unsigned int node;
+ struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
+
+ mlog_entry("%p %u %p", msg, len, data);
+
+ if (!dlm_grab(dlm))
+ return 0;
+
+ node = exit_msg->node_idx;
+
+ mlog(0, "Node %u leaves domain %s\n", node, dlm->name);
+
+ spin_lock(&dlm->spinlock);
+ clear_bit(node, dlm->domain_map);
+ __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,
+ unsigned int node)
+{
+ int status;
+ struct dlm_exit_domain leave_msg;
+
+ mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
+ node, dlm->name, dlm->node_num);
+
+ memset(&leave_msg, 0, sizeof(leave_msg));
+ leave_msg.node_idx = dlm->node_num;
+
+ status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
+ &leave_msg, sizeof(leave_msg), node,
+ NULL);
+
+ mlog(0, "status return %d from o2net_send_message\n", status);
+
+ return status;
+}
+
+
+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, 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_joined(struct dlm_ctxt *dlm)
+{
+ int ret = 0;
+
+ spin_lock(&dlm_domain_lock);
+
+ if (dlm->dlm_state == DLM_CTXT_JOINED)
+ ret = 1;
+
+ spin_unlock(&dlm_domain_lock);
+
+ return ret;
+}
+
+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;
+
+ 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);
+
+ /* We changed dlm state, notify the thread */
+ dlm_kick_thread(dlm, NULL);
+
+ dlm_migrate_all_locks(dlm);
+ dlm_mark_domain_leaving(dlm);
+ dlm_leave_domain(dlm);
+ dlm_complete_dlm_shutdown(dlm);
+ }
+ dlm_put(dlm);
+}
+EXPORT_SYMBOL_GPL(dlm_unregister_domain);
+
+static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data)
+{
+ struct dlm_query_join_request *query;
+ enum dlm_query_join_response response;
+ struct dlm_ctxt *dlm = NULL;
+
+ 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(query->node_idx)) {
+ mlog(0, "node %u is not in our live map yet\n",
+ query->node_idx);
+
+ response = JOIN_DISALLOW;
+ goto respond;
+ }
+
+ response = JOIN_OK_NO_MAP;
+
+ spin_lock(&dlm_domain_lock);
+ dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
+ /* Once the dlm ctxt is marked as leaving then we don't want
+ * to be put in someone's domain map. */
+ if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
+ 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. */
+ response = JOIN_OK_NO_MAP;
+ } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
+ /* Disallow parallel joins. */
+ response = 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. */
+ response = JOIN_OK;
+ __dlm_set_joining_node(dlm, query->node_idx);
+ }
+
+ spin_unlock(&dlm->spinlock);
+ }
+ spin_unlock(&dlm_domain_lock);
+
+respond:
+ mlog(0, "We respond with %u\n", response);
+
+ return response;
+}
+
+static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *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);
+ set_bit(assert->node_idx, dlm->domain_map);
+ __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
+
+ __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_cancel_join_handler(struct o2net_msg *msg, u32 len, void *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_errno(status);
+ 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, 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 *response)
+{
+ int status, retval;
+ struct dlm_query_join_request join_msg;
+
+ 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);
+
+ status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
+ sizeof(join_msg), node, &retval);
+ if (status < 0 && status != -ENOPROTOOPT) {
+ mlog_errno(status);
+ goto bail;
+ }
+
+ /* -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 (retval == JOIN_DISALLOW ||
+ retval == JOIN_OK ||
+ retval == JOIN_OK_NO_MAP) {
+ *response = retval;
+ } else {
+ status = -EINVAL;
+ mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
+ 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;
+ 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,
+ NULL);
+ if (status < 0)
+ mlog_errno(status);
+
+ 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 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 response;
+
+ mlog_entry("%p", dlm);
+
+ ctxt = kcalloc(1, 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);
+
+ 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)
+ __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->dlm_hb_up);
+ o2hb_unregister_callback(&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->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->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, &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->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, &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, &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, &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, &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, &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, &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, &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, &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, &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, &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, &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, &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;
+
+ 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;
+ }
+
+ do {
+ unsigned int backoff;
+ 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. */
+ if (status == -EAGAIN) {
+ if (signal_pending(current)) {
+ status = -ERESTARTSYS;
+ 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;
+ 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_complete_thread(dlm);
+ dlm_complete_recovery_thread(dlm);
+ }
+
+ return status;
+}
+
+static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
+ u32 key)
+{
+ int i;
+ struct dlm_ctxt *dlm = NULL;
+
+ dlm = kcalloc(1, sizeof(*dlm), GFP_KERNEL);
+ if (!dlm) {
+ mlog_errno(-ENOMEM);
+ goto leave;
+ }
+
+ dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
+ if (dlm->name == NULL) {
+ mlog_errno(-ENOMEM);
+ kfree(dlm);
+ dlm = NULL;
+ goto leave;
+ }
+
+ dlm->resources = (struct list_head *) __get_free_page(GFP_KERNEL);
+ if (!dlm->resources) {
+ mlog_errno(-ENOMEM);
+ kfree(dlm->name);
+ kfree(dlm);
+ dlm = NULL;
+ goto leave;
+ }
+ memset(dlm->resources, 0, PAGE_SIZE);
+
+ for (i=0; i<DLM_HASH_SIZE; i++)
+ INIT_LIST_HEAD(&dlm->resources[i]);
+
+ strcpy(dlm->name, domain);
+ dlm->key = key;
+ dlm->node_num = o2nm_this_node();
+
+ spin_lock_init(&dlm->spinlock);
+ spin_lock_init(&dlm->master_lock);
+ spin_lock_init(&dlm->ast_lock);
+ INIT_LIST_HEAD(&dlm->list);
+ INIT_LIST_HEAD(&dlm->dirty_list);
+ INIT_LIST_HEAD(&dlm->reco.resources);
+ INIT_LIST_HEAD(&dlm->reco.received);
+ INIT_LIST_HEAD(&dlm->reco.node_data);
+ INIT_LIST_HEAD(&dlm->purge_list);
+ INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
+ 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;
+ 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->master_list);
+ 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->local_resources, 0);
+ atomic_set(&dlm->remote_resources, 0);
+ atomic_set(&dlm->unknown_resources, 0);
+
+ spin_lock_init(&dlm->work_lock);
+ INIT_LIST_HEAD(&dlm->work_list);
+ INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work, dlm);
+
+ 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:
+ return dlm;
+}
+
+/*
+ * dlm_register_domain: one-time setup per "domain"
+ */
+struct dlm_ctxt * dlm_register_domain(const char *domain,
+ u32 key)
+{
+ 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;
+ }
+
+ if (!o2hb_check_local_node_heartbeating()) {
+ mlog(ML_ERROR, "the local node has not been configured, or is "
+ "not heartbeating\n");
+ ret = -EPROTO;
+ 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;
+ }
+
+ __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);
+
+ ret = dlm_join_domain(dlm);
+ if (ret) {
+ mlog_errno(ret);
+ dlm_put(dlm);
+ goto leave;
+ }
+
+ 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, &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, &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, &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 list_head *iter;
+ struct dlm_eviction_cb *cb;
+
+ down_read(&dlm_callback_sem);
+ list_for_each(iter, &dlm->dlm_eviction_callbacks) {
+ cb = list_entry(iter, struct dlm_eviction_cb, 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;
+
+ dlm_print_version();
+
+ status = dlm_init_mle_cache();
+ if (status)
+ return -1;
+
+ status = dlm_register_net_handlers();
+ if (status) {
+ dlm_destroy_mle_cache();
+ return -1;
+ }
+
+ return 0;
+}
+
+static void __exit dlm_exit (void)
+{
+ dlm_unregister_net_handlers();
+ dlm_destroy_mle_cache();
+}
+
+MODULE_AUTHOR("Oracle");
+MODULE_LICENSE("GPL");
+
+module_init(dlm_init);
+module_exit(dlm_exit);