fs/ocfs2/stackglue.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * stackglue.c
   4  *
   5  * Code which implements an OCFS2 specific interface to underlying
   6  * cluster stacks.
   7  *
   8  * Copyright (C) 2007, 2009 Oracle.  All rights reserved.
   9  */
  10
  11 #include <linux/list.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/kmod.h>
  16 #include <linux/fs.h>
  17 #include <linux/kobject.h>
  18 #include <linux/sysfs.h>
  19 #include <linux/sysctl.h>
  20
  21 #include "ocfs2_fs.h"
  22
  23 #include "stackglue.h"
  24
  25 #define OCFS2_STACK_PLUGIN_O2CB         "o2cb"
  26 #define OCFS2_STACK_PLUGIN_USER         "user"
  27 #define OCFS2_MAX_HB_CTL_PATH           256
  28
  29 static struct ocfs2_protocol_version locking_max_version;
  30 static DEFINE_SPINLOCK(ocfs2_stack_lock);
  31 static LIST_HEAD(ocfs2_stack_list);
  32 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
  33 static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
  34
  35 /*
  36  * The stack currently in use.  If not null, active_stack->sp_count > 0,
  37  * the module is pinned, and the locking protocol cannot be changed.
  38  */
  39 static struct ocfs2_stack_plugin *active_stack;
  40
  41 static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
  42 {
  43         struct ocfs2_stack_plugin *p;
  44
  45         assert_spin_locked(&ocfs2_stack_lock);
  46
  47         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
  48                 if (!strcmp(p->sp_name, name))
  49                         return p;
  50         }
  51
  52         return NULL;
  53 }
  54
  55 static int ocfs2_stack_driver_request(const char *stack_name,
  56                                       const char *plugin_name)
  57 {
  58         int rc;
  59         struct ocfs2_stack_plugin *p;
  60
  61         spin_lock(&ocfs2_stack_lock);
  62
  63         /*
  64          * If the stack passed by the filesystem isn't the selected one,
  65          * we can't continue.
  66          */
  67         if (strcmp(stack_name, cluster_stack_name)) {
  68                 rc = -EBUSY;
  69                 goto out;
  70         }
  71
  72         if (active_stack) {
  73                 /*
  74                  * If the active stack isn't the one we want, it cannot
  75                  * be selected right now.
  76                  */
  77                 if (!strcmp(active_stack->sp_name, plugin_name))
  78                         rc = 0;
  79                 else
  80                         rc = -EBUSY;
  81                 goto out;
  82         }
  83
  84         p = ocfs2_stack_lookup(plugin_name);
  85         if (!p || !try_module_get(p->sp_owner)) {
  86                 rc = -ENOENT;
  87                 goto out;
  88         }
  89
  90         active_stack = p;
  91         rc = 0;
  92
  93 out:
  94         /* If we found it, pin it */
  95         if (!rc)
  96                 active_stack->sp_count++;
  97
  98         spin_unlock(&ocfs2_stack_lock);
  99         return rc;
 100 }
 101
 102 /*
 103  * This function looks up the appropriate stack and makes it active.  If
 104  * there is no stack, it tries to load it.  It will fail if the stack still
 105  * cannot be found.  It will also fail if a different stack is in use.
 106  */
 107 static int ocfs2_stack_driver_get(const char *stack_name)
 108 {
 109         int rc;
 110         char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
 111
 112         /*
 113          * Classic stack does not pass in a stack name.  This is
 114          * compatible with older tools as well.
 115          */
 116         if (!stack_name || !*stack_name)
 117                 stack_name = OCFS2_STACK_PLUGIN_O2CB;
 118
 119         if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
 120                 printk(KERN_ERR
 121                        "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
 122                        stack_name);
 123                 return -EINVAL;
 124         }
 125
 126         /* Anything that isn't the classic stack is a user stack */
 127         if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
 128                 plugin_name = OCFS2_STACK_PLUGIN_USER;
 129
 130         rc = ocfs2_stack_driver_request(stack_name, plugin_name);
 131         if (rc == -ENOENT) {
 132                 request_module("ocfs2_stack_%s", plugin_name);
 133                 rc = ocfs2_stack_driver_request(stack_name, plugin_name);
 134         }
 135
 136         if (rc == -ENOENT) {
 137                 printk(KERN_ERR
 138                        "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
 139                        plugin_name);
 140         } else if (rc == -EBUSY) {
 141                 printk(KERN_ERR
 142                        "ocfs2: A different cluster stack is in use\n");
 143         }
 144
 145         return rc;
 146 }
 147
 148 static void ocfs2_stack_driver_put(void)
 149 {
 150         spin_lock(&ocfs2_stack_lock);
 151         BUG_ON(active_stack == NULL);
 152         BUG_ON(active_stack->sp_count == 0);
 153
 154         active_stack->sp_count--;
 155         if (!active_stack->sp_count) {
 156                 module_put(active_stack->sp_owner);
 157                 active_stack = NULL;
 158         }
 159         spin_unlock(&ocfs2_stack_lock);
 160 }
 161
 162 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
 163 {
 164         int rc;
 165
 166         spin_lock(&ocfs2_stack_lock);
 167         if (!ocfs2_stack_lookup(plugin->sp_name)) {
 168                 plugin->sp_count = 0;
 169                 plugin->sp_max_proto = locking_max_version;
 170                 list_add(&plugin->sp_list, &ocfs2_stack_list);
 171                 printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
 172                        plugin->sp_name);
 173                 rc = 0;
 174         } else {
 175                 printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
 176                        plugin->sp_name);
 177                 rc = -EEXIST;
 178         }
 179         spin_unlock(&ocfs2_stack_lock);
 180
 181         return rc;
 182 }
 183 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
 184
 185 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
 186 {
 187         struct ocfs2_stack_plugin *p;
 188
 189         spin_lock(&ocfs2_stack_lock);
 190         p = ocfs2_stack_lookup(plugin->sp_name);
 191         if (p) {
 192                 BUG_ON(p != plugin);
 193                 BUG_ON(plugin == active_stack);
 194                 BUG_ON(plugin->sp_count != 0);
 195                 list_del_init(&plugin->sp_list);
 196                 printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
 197                        plugin->sp_name);
 198         } else {
 199                 printk(KERN_ERR "Stack \"%s\" is not registered\n",
 200                        plugin->sp_name);
 201         }
 202         spin_unlock(&ocfs2_stack_lock);
 203 }
 204 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
 205
 206 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
 207 {
 208         struct ocfs2_stack_plugin *p;
 209
 210         spin_lock(&ocfs2_stack_lock);
 211         if (memcmp(max_proto, &locking_max_version,
 212                    sizeof(struct ocfs2_protocol_version))) {
 213                 BUG_ON(locking_max_version.pv_major != 0);
 214
 215                 locking_max_version = *max_proto;
 216                 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 217                         p->sp_max_proto = locking_max_version;
 218                 }
 219         }
 220         spin_unlock(&ocfs2_stack_lock);
 221 }
 222 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
 223
 224
 225 /*
 226  * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
 227  * for the ast and bast functions.  They will pass the lksb to the ast
 228  * and bast.  The caller can wrap the lksb with their own structure to
 229  * get more information.
 230  */
 231 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
 232                    int mode,
 233                    struct ocfs2_dlm_lksb *lksb,
 234                    u32 flags,
 235                    void *name,
 236                    unsigned int namelen)
 237 {
 238         if (!lksb->lksb_conn)
 239                 lksb->lksb_conn = conn;
 240         else
 241                 BUG_ON(lksb->lksb_conn != conn);
 242         return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
 243                                               name, namelen);
 244 }
 245 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
 246
 247 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
 248                      struct ocfs2_dlm_lksb *lksb,
 249                      u32 flags)
 250 {
 251         BUG_ON(lksb->lksb_conn == NULL);
 252
 253         return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
 254 }
 255 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
 256
 257 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
 258 {
 259         return active_stack->sp_ops->lock_status(lksb);
 260 }
 261 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
 262
 263 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
 264 {
 265         return active_stack->sp_ops->lvb_valid(lksb);
 266 }
 267 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
 268
 269 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
 270 {
 271         return active_stack->sp_ops->lock_lvb(lksb);
 272 }
 273 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
 274
 275 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
 276 {
 277         active_stack->sp_ops->dump_lksb(lksb);
 278 }
 279 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
 280
 281 int ocfs2_stack_supports_plocks(void)
 282 {
 283         return active_stack && active_stack->sp_ops->plock;
 284 }
 285 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
 286
 287 /*
 288  * ocfs2_plock() can only be safely called if
 289  * ocfs2_stack_supports_plocks() returned true
 290  */
 291 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
 292                 struct file *file, int cmd, struct file_lock *fl)
 293 {
 294         WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
 295         if (active_stack->sp_ops->plock)
 296                 return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
 297         return -EOPNOTSUPP;
 298 }
 299 EXPORT_SYMBOL_GPL(ocfs2_plock);
 300
 301 int ocfs2_cluster_connect(const char *stack_name,
 302                           const char *cluster_name,
 303                           int cluster_name_len,
 304                           const char *group,
 305                           int grouplen,
 306                           struct ocfs2_locking_protocol *lproto,
 307                           void (*recovery_handler)(int node_num,
 308                                                    void *recovery_data),
 309                           void *recovery_data,
 310                           struct ocfs2_cluster_connection **conn)
 311 {
 312         int rc = 0;
 313         struct ocfs2_cluster_connection *new_conn;
 314
 315         BUG_ON(group == NULL);
 316         BUG_ON(conn == NULL);
 317         BUG_ON(recovery_handler == NULL);
 318
 319         if (grouplen > GROUP_NAME_MAX) {
 320                 rc = -EINVAL;
 321                 goto out;
 322         }
 323
 324         if (memcmp(&lproto->lp_max_version, &locking_max_version,
 325                    sizeof(struct ocfs2_protocol_version))) {
 326                 rc = -EINVAL;
 327                 goto out;
 328         }
 329
 330         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
 331                            GFP_KERNEL);
 332         if (!new_conn) {
 333                 rc = -ENOMEM;
 334                 goto out;
 335         }
 336
 337         strscpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
 338         new_conn->cc_namelen = grouplen;
 339         if (cluster_name_len)
 340                 strscpy(new_conn->cc_cluster_name, cluster_name,
 341                         CLUSTER_NAME_MAX + 1);
 342         new_conn->cc_cluster_name_len = cluster_name_len;
 343         new_conn->cc_recovery_handler = recovery_handler;
 344         new_conn->cc_recovery_data = recovery_data;
 345
 346         new_conn->cc_proto = lproto;
 347         /* Start the new connection at our maximum compatibility level */
 348         new_conn->cc_version = lproto->lp_max_version;
 349
 350         /* This will pin the stack driver if successful */
 351         rc = ocfs2_stack_driver_get(stack_name);
 352         if (rc)
 353                 goto out_free;
 354
 355         rc = active_stack->sp_ops->connect(new_conn);
 356         if (rc) {
 357                 ocfs2_stack_driver_put();
 358                 goto out_free;
 359         }
 360
 361         *conn = new_conn;
 362
 363 out_free:
 364         if (rc)
 365                 kfree(new_conn);
 366
 367 out:
 368         return rc;
 369 }
 370 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
 371
 372 /* The caller will ensure all nodes have the same cluster stack */
 373 int ocfs2_cluster_connect_agnostic(const char *group,
 374                                    int grouplen,
 375                                    struct ocfs2_locking_protocol *lproto,
 376                                    void (*recovery_handler)(int node_num,
 377                                                             void *recovery_data),
 378                                    void *recovery_data,
 379                                    struct ocfs2_cluster_connection **conn)
 380 {
 381         char *stack_name = NULL;
 382
 383         if (cluster_stack_name[0])
 384                 stack_name = cluster_stack_name;
 385         return ocfs2_cluster_connect(stack_name, NULL, 0, group, grouplen,
 386                                      lproto, recovery_handler, recovery_data,
 387                                      conn);
 388 }
 389 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
 390
 391 /* If hangup_pending is 0, the stack driver will be dropped */
 392 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 393                              int hangup_pending)
 394 {
 395         int ret;
 396
 397         BUG_ON(conn == NULL);
 398
 399         ret = active_stack->sp_ops->disconnect(conn);
 400
 401         /* XXX Should we free it anyway? */
 402         if (!ret) {
 403                 kfree(conn);
 404                 if (!hangup_pending)
 405                         ocfs2_stack_driver_put();
 406         }
 407
 408         return ret;
 409 }
 410 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 411
 412 /*
 413  * Leave the group for this filesystem.  This is executed by a userspace
 414  * program (stored in ocfs2_hb_ctl_path).
 415  */
 416 static void ocfs2_leave_group(const char *group)
 417 {
 418         int ret;
 419         char *argv[5], *envp[3];
 420
 421         argv[0] = ocfs2_hb_ctl_path;
 422         argv[1] = "-K";
 423         argv[2] = "-u";
 424         argv[3] = (char *)group;
 425         argv[4] = NULL;
 426
 427         /* minimal command environment taken from cpu_run_sbin_hotplug */
 428         envp[0] = "HOME=/";
 429         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 430         envp[2] = NULL;
 431
 432         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 433         if (ret < 0) {
 434                 printk(KERN_ERR
 435                        "ocfs2: Error %d running user helper "
 436                        "\"%s %s %s %s\"\n",
 437                        ret, argv[0], argv[1], argv[2], argv[3]);
 438         }
 439 }
 440
 441 /*
 442  * Hangup is a required post-umount.  ocfs2-tools software expects the
 443  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
 444  * regardless of whether the DLM got started, so we can't do it
 445  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
 446  * the actual work.
 447  */
 448 void ocfs2_cluster_hangup(const char *group, int grouplen)
 449 {
 450         BUG_ON(group == NULL);
 451         BUG_ON(group[grouplen] != '\0');
 452
 453         ocfs2_leave_group(group);
 454
 455         /* cluster_disconnect() was called with hangup_pending==1 */
 456         ocfs2_stack_driver_put();
 457 }
 458 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
 459
 460 int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
 461                             unsigned int *node)
 462 {
 463         return active_stack->sp_ops->this_node(conn, node);
 464 }
 465 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
 466
 467
 468 /*
 469  * Sysfs bits
 470  */
 471
 472 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
 473                                                struct kobj_attribute *attr,
 474                                                char *buf)
 475 {
 476         ssize_t ret = 0;
 477
 478         spin_lock(&ocfs2_stack_lock);
 479         if (locking_max_version.pv_major)
 480                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
 481                                locking_max_version.pv_major,
 482                                locking_max_version.pv_minor);
 483         spin_unlock(&ocfs2_stack_lock);
 484
 485         return ret;
 486 }
 487
 488 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
 489         __ATTR(max_locking_protocol, S_IRUGO,
 490                ocfs2_max_locking_protocol_show, NULL);
 491
 492 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
 493                                                  struct kobj_attribute *attr,
 494                                                  char *buf)
 495 {
 496         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
 497         struct ocfs2_stack_plugin *p;
 498
 499         spin_lock(&ocfs2_stack_lock);
 500         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 501                 ret = snprintf(buf, remain, "%s\n",
 502                                p->sp_name);
 503                 if (ret >= remain) {
 504                         /* snprintf() didn't fit */
 505                         total = -E2BIG;
 506                         break;
 507                 }
 508                 total += ret;
 509                 remain -= ret;
 510         }
 511         spin_unlock(&ocfs2_stack_lock);
 512
 513         return total;
 514 }
 515
 516 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
 517         __ATTR(loaded_cluster_plugins, S_IRUGO,
 518                ocfs2_loaded_cluster_plugins_show, NULL);
 519
 520 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
 521                                                 struct kobj_attribute *attr,
 522                                                 char *buf)
 523 {
 524         ssize_t ret = 0;
 525
 526         spin_lock(&ocfs2_stack_lock);
 527         if (active_stack) {
 528                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 529                                active_stack->sp_name);
 530                 if (ret >= PAGE_SIZE)
 531                         ret = -E2BIG;
 532         }
 533         spin_unlock(&ocfs2_stack_lock);
 534
 535         return ret;
 536 }
 537
 538 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
 539         __ATTR(active_cluster_plugin, S_IRUGO,
 540                ocfs2_active_cluster_plugin_show, NULL);
 541
 542 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
 543                                         struct kobj_attribute *attr,
 544                                         char *buf)
 545 {
 546         ssize_t ret;
 547         spin_lock(&ocfs2_stack_lock);
 548         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
 549         spin_unlock(&ocfs2_stack_lock);
 550
 551         return ret;
 552 }
 553
 554 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 555                                          struct kobj_attribute *attr,
 556                                          const char *buf, size_t count)
 557 {
 558         size_t len = count;
 559         ssize_t ret;
 560
 561         if (len == 0)
 562                 return len;
 563
 564         if (buf[len - 1] == '\n')
 565                 len--;
 566
 567         if ((len != OCFS2_STACK_LABEL_LEN) ||
 568             (strnlen(buf, len) != len))
 569                 return -EINVAL;
 570
 571         spin_lock(&ocfs2_stack_lock);
 572         if (active_stack) {
 573                 if (!strncmp(buf, cluster_stack_name, len))
 574                         ret = count;
 575                 else
 576                         ret = -EBUSY;
 577         } else {
 578                 memcpy(cluster_stack_name, buf, len);
 579                 ret = count;
 580         }
 581         spin_unlock(&ocfs2_stack_lock);
 582
 583         return ret;
 584 }
 585
 586
 587 static struct kobj_attribute ocfs2_attr_cluster_stack =
 588         __ATTR(cluster_stack, S_IRUGO | S_IWUSR,
 589                ocfs2_cluster_stack_show,
 590                ocfs2_cluster_stack_store);
 591
 592
 593
 594 static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
 595                                         struct kobj_attribute *attr,
 596                                         char *buf)
 597 {
 598         return snprintf(buf, PAGE_SIZE, "1\n");
 599 }
 600
 601 static struct kobj_attribute ocfs2_attr_dlm_recover_support =
 602         __ATTR(dlm_recover_callback_support, S_IRUGO,
 603                ocfs2_dlm_recover_show, NULL);
 604
 605 static struct attribute *ocfs2_attrs[] = {
 606         &ocfs2_attr_max_locking_protocol.attr,
 607         &ocfs2_attr_loaded_cluster_plugins.attr,
 608         &ocfs2_attr_active_cluster_plugin.attr,
 609         &ocfs2_attr_cluster_stack.attr,
 610         &ocfs2_attr_dlm_recover_support.attr,
 611         NULL,
 612 };
 613
 614 static const struct attribute_group ocfs2_attr_group = {
 615         .attrs = ocfs2_attrs,
 616 };
 617
 618 struct kset *ocfs2_kset;
 619 EXPORT_SYMBOL_GPL(ocfs2_kset);
 620
 621 static void ocfs2_sysfs_exit(void)
 622 {
 623         kset_unregister(ocfs2_kset);
 624 }
 625
 626 static int ocfs2_sysfs_init(void)
 627 {
 628         int ret;
 629
 630         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
 631         if (!ocfs2_kset)
 632                 return -ENOMEM;
 633
 634         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
 635         if (ret)
 636                 goto error;
 637
 638         return 0;
 639
 640 error:
 641         kset_unregister(ocfs2_kset);
 642         return ret;
 643 }
 644
 645 /*
 646  * Sysctl bits
 647  *
 648  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
 649  * make as much sense in a multiple cluster stack world, but it's safer
 650  * and easier to preserve the name.
 651  */
 652
 653 static struct ctl_table ocfs2_nm_table[] = {
 654         {
 655                 .procname       = "hb_ctl_path",
 656                 .data           = ocfs2_hb_ctl_path,
 657                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
 658                 .mode           = 0644,
 659                 .proc_handler   = proc_dostring,
 660         },
 661 };
 662
 663 static struct ctl_table_header *ocfs2_table_header;
 664
 665 /*
 666  * Initialization
 667  */
 668
 669 static int __init ocfs2_stack_glue_init(void)
 670 {
 671         int ret;
 672
 673         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 674
 675         ocfs2_table_header = register_sysctl("fs/ocfs2/nm", ocfs2_nm_table);
 676         if (!ocfs2_table_header) {
 677                 printk(KERN_ERR
 678                        "ocfs2 stack glue: unable to register sysctl\n");
 679                 return -ENOMEM; /* or something. */
 680         }
 681
 682         ret = ocfs2_sysfs_init();
 683         if (ret)
 684                 unregister_sysctl_table(ocfs2_table_header);
 685
 686         return ret;
 687 }
 688
 689 static void __exit ocfs2_stack_glue_exit(void)
 690 {
 691         memset(&locking_max_version, 0,
 692                sizeof(struct ocfs2_protocol_version));
 693         ocfs2_sysfs_exit();
 694         if (ocfs2_table_header)
 695                 unregister_sysctl_table(ocfs2_table_header);
 696 }
 697
 698 MODULE_AUTHOR("Oracle");
 699 MODULE_DESCRIPTION("ocfs2 cluster stack glue layer");
 700 MODULE_LICENSE("GPL");
 701 module_init(ocfs2_stack_glue_init);
 702 module_exit(ocfs2_stack_glue_exit);