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kernel-fxtec-pro1x/fs/ocfs2/dlm/dlmdomain.c
Sunil Mushran 2f5bf1f2d0 ocfs2_dlm: Check for migrateable lockres in dlm_empty_lockres() 
In dlm_migrate_lockres(), we check upfront whether the lockres is a
candidate for migration. This patch encapsulates that code in a separate
function so that dlm_empty_lockres() can also use it during umount. This
patch addresses the umount process spinning problem.

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-03-26 16:51:15 -07:00

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/* -*- 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 "dlmdomain.h"
#include "dlmver.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);
#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_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data);
static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
{
if (!hlist_unhashed(&lockres->hash_node)) {
hlist_del_init(&lockres->hash_node);
dlm_lockres_put(lockres);
}
}
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);
}
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 hlist_node *list;
mlog_entry("%.*s\n", len, name);
assert_spin_locked(&dlm->spinlock);
bucket = dlm_lockres_hash(dlm, hash);
hlist_for_each(list, bucket) {
struct dlm_lock_resource *res = hlist_entry(list,
struct dlm_lock_resource, 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_entry("%.*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 = 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->lockres_hash)
dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
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_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_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);
__dlm_lockres_calc_usage(dlm, res);
iter = res->hash_node.next;
spin_unlock(&res->spinlock);
dlm_lockres_put(res);
cond_resched_lock(&dlm->spinlock);
if (dropped)
goto redo_bucket;
}
num += n;
mlog(0, "%s: touched %d lockreses in bucket %d "
"(tot=%d)\n", dlm->name, n, i, num);
}
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 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);
printk(KERN_INFO "ocfs2_dlm: Nodes in domain (\"%s\"): ", dlm->name);
while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
node + 1)) < O2NM_MAX_NODES) {
printk("%d ", node);
}
printk("\n");
}
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_entry("%p %u %p", msg, len, data);
if (!dlm_grab(dlm))
return 0;
node = exit_msg->node_idx;
printk(KERN_INFO "ocfs2_dlm: 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);
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);
}
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,
void **ret_data)
{
struct dlm_query_join_request *query;
enum dlm_query_join_response response;
struct dlm_ctxt *dlm = NULL;
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(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);
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);
response = 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->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. */
response = JOIN_OK_NO_MAP;
} else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
/* Disallow parallel joins. */
response = JOIN_DISALLOW;
} else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
mlog(0, "node %u trying to join, but recovery "
"is ongoing.\n", bit);
response = JOIN_DISALLOW;
} else if (test_bit(bit, dlm->recovery_map)) {
mlog(0, "node %u trying to join, but it "
"still needs recovery.\n", bit);
response = 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);
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);
}
unlock_respond:
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,
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);
set_bit(assert->node_idx, dlm->domain_map);
__dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
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_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_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);
/* 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, &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 = 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);
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, 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;
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;
}
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 >
msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
status = -ERESTARTSYS;
mlog(ML_NOTICE, "Timed out joining dlm domain "
"%s after %u msecs\n", dlm->name,
jiffies_to_msecs(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_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;
struct dlm_ctxt *dlm = NULL;
dlm = kzalloc(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->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
if (!dlm->lockres_hash) {
mlog_errno(-ENOMEM);
kfree(dlm->name);
kfree(dlm);
dlm = NULL;
goto leave;
}
for (i = 0; i < DLM_HASH_BUCKETS; i++)
INIT_HLIST_HEAD(dlm_lockres_hash(dlm, 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;
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->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);
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, 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);
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);
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