git.oblomov.eu Git - linux-2.6/blob - fs/ocfs2/stackglue.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * stackglue.c
   5  *
   6  * Code which implements an OCFS2 specific interface to underlying
   7  * cluster stacks.
   8  *
   9  * Copyright (C) 2007 Oracle.  All rights reserved.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public
  13  * License as published by the Free Software Foundation, version 2.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  */
  20
  21 #include <linux/list.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/kmod.h>
  26 #include <linux/fs.h>
  27 #include <linux/kobject.h>
  28 #include <linux/sysfs.h>
  29 #include <linux/sysctl.h>
  30
  31 #include "ocfs2_fs.h"
  32
  33 #include "stackglue.h"
  34
  35 #define OCFS2_STACK_PLUGIN_O2CB         "o2cb"
  36 #define OCFS2_STACK_PLUGIN_USER         "user"
  37 #define OCFS2_MAX_HB_CTL_PATH           256
  38
  39 static struct ocfs2_locking_protocol *lproto;
  40 static DEFINE_SPINLOCK(ocfs2_stack_lock);
  41 static LIST_HEAD(ocfs2_stack_list);
  42 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
  43 static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
  44
  45 /*
  46  * The stack currently in use.  If not null, active_stack->sp_count > 0,
  47  * the module is pinned, and the locking protocol cannot be changed.
  48  */
  49 static struct ocfs2_stack_plugin *active_stack;
  50
  51 static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
  52 {
  53         struct ocfs2_stack_plugin *p;
  54
  55         assert_spin_locked(&ocfs2_stack_lock);
  56
  57         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
  58                 if (!strcmp(p->sp_name, name))
  59                         return p;
  60         }
  61
  62         return NULL;
  63 }
  64
  65 static int ocfs2_stack_driver_request(const char *stack_name,
  66                                       const char *plugin_name)
  67 {
  68         int rc;
  69         struct ocfs2_stack_plugin *p;
  70
  71         spin_lock(&ocfs2_stack_lock);
  72
  73         /*
  74          * If the stack passed by the filesystem isn't the selected one,
  75          * we can't continue.
  76          */
  77         if (strcmp(stack_name, cluster_stack_name)) {
  78                 rc = -EBUSY;
  79                 goto out;
  80         }
  81
  82         if (active_stack) {
  83                 /*
  84                  * If the active stack isn't the one we want, it cannot
  85                  * be selected right now.
  86                  */
  87                 if (!strcmp(active_stack->sp_name, plugin_name))
  88                         rc = 0;
  89                 else
  90                         rc = -EBUSY;
  91                 goto out;
  92         }
  93
  94         p = ocfs2_stack_lookup(plugin_name);
  95         if (!p || !try_module_get(p->sp_owner)) {
  96                 rc = -ENOENT;
  97                 goto out;
  98         }
  99
 100         /* Ok, the stack is pinned */
 101         p->sp_count++;
 102         active_stack = p;
 103
 104         rc = 0;
 105
 106 out:
 107         spin_unlock(&ocfs2_stack_lock);
 108         return rc;
 109 }
 110
 111 /*
 112  * This function looks up the appropriate stack and makes it active.  If
 113  * there is no stack, it tries to load it.  It will fail if the stack still
 114  * cannot be found.  It will also fail if a different stack is in use.
 115  */
 116 static int ocfs2_stack_driver_get(const char *stack_name)
 117 {
 118         int rc;
 119         char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
 120
 121         /*
 122          * Classic stack does not pass in a stack name.  This is
 123          * compatible with older tools as well.
 124          */
 125         if (!stack_name || !*stack_name)
 126                 stack_name = OCFS2_STACK_PLUGIN_O2CB;
 127
 128         if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
 129                 printk(KERN_ERR
 130                        "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
 131                        stack_name);
 132                 return -EINVAL;
 133         }
 134
 135         /* Anything that isn't the classic stack is a user stack */
 136         if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
 137                 plugin_name = OCFS2_STACK_PLUGIN_USER;
 138
 139         rc = ocfs2_stack_driver_request(stack_name, plugin_name);
 140         if (rc == -ENOENT) {
 141                 request_module("ocfs2_stack_%s", plugin_name);
 142                 rc = ocfs2_stack_driver_request(stack_name, plugin_name);
 143         }
 144
 145         if (rc == -ENOENT) {
 146                 printk(KERN_ERR
 147                        "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
 148                        plugin_name);
 149         } else if (rc == -EBUSY) {
 150                 printk(KERN_ERR
 151                        "ocfs2: A different cluster stack is in use\n");
 152         }
 153
 154         return rc;
 155 }
 156
 157 static void ocfs2_stack_driver_put(void)
 158 {
 159         spin_lock(&ocfs2_stack_lock);
 160         BUG_ON(active_stack == NULL);
 161         BUG_ON(active_stack->sp_count == 0);
 162
 163         active_stack->sp_count--;
 164         if (!active_stack->sp_count) {
 165                 module_put(active_stack->sp_owner);
 166                 active_stack = NULL;
 167         }
 168         spin_unlock(&ocfs2_stack_lock);
 169 }
 170
 171 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
 172 {
 173         int rc;
 174
 175         spin_lock(&ocfs2_stack_lock);
 176         if (!ocfs2_stack_lookup(plugin->sp_name)) {
 177                 plugin->sp_count = 0;
 178                 plugin->sp_proto = lproto;
 179                 list_add(&plugin->sp_list, &ocfs2_stack_list);
 180                 printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
 181                        plugin->sp_name);
 182                 rc = 0;
 183         } else {
 184                 printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
 185                        plugin->sp_name);
 186                 rc = -EEXIST;
 187         }
 188         spin_unlock(&ocfs2_stack_lock);
 189
 190         return rc;
 191 }
 192 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
 193
 194 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
 195 {
 196         struct ocfs2_stack_plugin *p;
 197
 198         spin_lock(&ocfs2_stack_lock);
 199         p = ocfs2_stack_lookup(plugin->sp_name);
 200         if (p) {
 201                 BUG_ON(p != plugin);
 202                 BUG_ON(plugin == active_stack);
 203                 BUG_ON(plugin->sp_count != 0);
 204                 list_del_init(&plugin->sp_list);
 205                 printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
 206                        plugin->sp_name);
 207         } else {
 208                 printk(KERN_ERR "Stack \"%s\" is not registered\n",
 209                        plugin->sp_name);
 210         }
 211         spin_unlock(&ocfs2_stack_lock);
 212 }
 213 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
 214
 215 void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto)
 216 {
 217         struct ocfs2_stack_plugin *p;
 218
 219         BUG_ON(proto == NULL);
 220
 221         spin_lock(&ocfs2_stack_lock);
 222         BUG_ON(active_stack != NULL);
 223
 224         lproto = proto;
 225         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 226                 p->sp_proto = lproto;
 227         }
 228
 229         spin_unlock(&ocfs2_stack_lock);
 230 }
 231 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_locking_protocol);
 232
 233
 234 /*
 235  * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take
 236  * "struct ocfs2_lock_res *astarg" instead of "void *astarg" because the
 237  * underlying stack plugins need to pilfer the lksb off of the lock_res.
 238  * If some other structure needs to be passed as an astarg, the plugins
 239  * will need to be given a different avenue to the lksb.
 240  */
 241 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
 242                    int mode,
 243                    union ocfs2_dlm_lksb *lksb,
 244                    u32 flags,
 245                    void *name,
 246                    unsigned int namelen,
 247                    struct ocfs2_lock_res *astarg)
 248 {
 249         BUG_ON(lproto == NULL);
 250
 251         return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
 252                                               name, namelen, astarg);
 253 }
 254 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
 255
 256 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
 257                      union ocfs2_dlm_lksb *lksb,
 258                      u32 flags,
 259                      struct ocfs2_lock_res *astarg)
 260 {
 261         BUG_ON(lproto == NULL);
 262
 263         return active_stack->sp_ops->dlm_unlock(conn, lksb, flags, astarg);
 264 }
 265 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
 266
 267 int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
 268 {
 269         return active_stack->sp_ops->lock_status(lksb);
 270 }
 271 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
 272
 273 /*
 274  * Why don't we cast to ocfs2_meta_lvb?  The "clean" answer is that we
 275  * don't cast at the glue level.  The real answer is that the header
 276  * ordering is nigh impossible.
 277  */
 278 void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb)
 279 {
 280         return active_stack->sp_ops->lock_lvb(lksb);
 281 }
 282 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
 283
 284 void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
 285 {
 286         active_stack->sp_ops->dump_lksb(lksb);
 287 }
 288 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
 289
 290 int ocfs2_cluster_connect(const char *stack_name,
 291                           const char *group,
 292                           int grouplen,
 293                           void (*recovery_handler)(int node_num,
 294                                                    void *recovery_data),
 295                           void *recovery_data,
 296                           struct ocfs2_cluster_connection **conn)
 297 {
 298         int rc = 0;
 299         struct ocfs2_cluster_connection *new_conn;
 300
 301         BUG_ON(group == NULL);
 302         BUG_ON(conn == NULL);
 303         BUG_ON(recovery_handler == NULL);
 304
 305         if (grouplen > GROUP_NAME_MAX) {
 306                 rc = -EINVAL;
 307                 goto out;
 308         }
 309
 310         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
 311                            GFP_KERNEL);
 312         if (!new_conn) {
 313                 rc = -ENOMEM;
 314                 goto out;
 315         }
 316
 317         memcpy(new_conn->cc_name, group, grouplen);
 318         new_conn->cc_namelen = grouplen;
 319         new_conn->cc_recovery_handler = recovery_handler;
 320         new_conn->cc_recovery_data = recovery_data;
 321
 322         /* Start the new connection at our maximum compatibility level */
 323         new_conn->cc_version = lproto->lp_max_version;
 324
 325         /* This will pin the stack driver if successful */
 326         rc = ocfs2_stack_driver_get(stack_name);
 327         if (rc)
 328                 goto out_free;
 329
 330         rc = active_stack->sp_ops->connect(new_conn);
 331         if (rc) {
 332                 ocfs2_stack_driver_put();
 333                 goto out_free;
 334         }
 335
 336         *conn = new_conn;
 337
 338 out_free:
 339         if (rc)
 340                 kfree(new_conn);
 341
 342 out:
 343         return rc;
 344 }
 345 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
 346
 347 /* If hangup_pending is 0, the stack driver will be dropped */
 348 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 349                              int hangup_pending)
 350 {
 351         int ret;
 352
 353         BUG_ON(conn == NULL);
 354
 355         ret = active_stack->sp_ops->disconnect(conn);
 356
 357         /* XXX Should we free it anyway? */
 358         if (!ret) {
 359                 kfree(conn);
 360                 if (!hangup_pending)
 361                         ocfs2_stack_driver_put();
 362         }
 363
 364         return ret;
 365 }
 366 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 367
 368 /*
 369  * Leave the group for this filesystem.  This is executed by a userspace
 370  * program (stored in ocfs2_hb_ctl_path).
 371  */
 372 static void ocfs2_leave_group(const char *group)
 373 {
 374         int ret;
 375         char *argv[5], *envp[3];
 376
 377         argv[0] = ocfs2_hb_ctl_path;
 378         argv[1] = "-K";
 379         argv[2] = "-u";
 380         argv[3] = (char *)group;
 381         argv[4] = NULL;
 382
 383         /* minimal command environment taken from cpu_run_sbin_hotplug */
 384         envp[0] = "HOME=/";
 385         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 386         envp[2] = NULL;
 387
 388         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 389         if (ret < 0) {
 390                 printk(KERN_ERR
 391                        "ocfs2: Error %d running user helper "
 392                        "\"%s %s %s %s\"\n",
 393                        ret, argv[0], argv[1], argv[2], argv[3]);
 394         }
 395 }
 396
 397 /*
 398  * Hangup is a required post-umount.  ocfs2-tools software expects the
 399  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
 400  * regardless of whether the DLM got started, so we can't do it
 401  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
 402  * the actual work.
 403  */
 404 void ocfs2_cluster_hangup(const char *group, int grouplen)
 405 {
 406         BUG_ON(group == NULL);
 407         BUG_ON(group[grouplen] != '\0');
 408
 409         ocfs2_leave_group(group);
 410
 411         /* cluster_disconnect() was called with hangup_pending==1 */
 412         ocfs2_stack_driver_put();
 413 }
 414 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
 415
 416 int ocfs2_cluster_this_node(unsigned int *node)
 417 {
 418         return active_stack->sp_ops->this_node(node);
 419 }
 420 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
 421
 422
 423 /*
 424  * Sysfs bits
 425  */
 426
 427 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
 428                                                struct kobj_attribute *attr,
 429                                                char *buf)
 430 {
 431         ssize_t ret = 0;
 432
 433         spin_lock(&ocfs2_stack_lock);
 434         if (lproto)
 435                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
 436                                lproto->lp_max_version.pv_major,
 437                                lproto->lp_max_version.pv_minor);
 438         spin_unlock(&ocfs2_stack_lock);
 439
 440         return ret;
 441 }
 442
 443 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
 444         __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
 445                ocfs2_max_locking_protocol_show, NULL);
 446
 447 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
 448                                                  struct kobj_attribute *attr,
 449                                                  char *buf)
 450 {
 451         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
 452         struct ocfs2_stack_plugin *p;
 453
 454         spin_lock(&ocfs2_stack_lock);
 455         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 456                 ret = snprintf(buf, remain, "%s\n",
 457                                p->sp_name);
 458                 if (ret < 0) {
 459                         total = ret;
 460                         break;
 461                 }
 462                 if (ret == remain) {
 463                         /* snprintf() didn't fit */
 464                         total = -E2BIG;
 465                         break;
 466                 }
 467                 total += ret;
 468                 remain -= ret;
 469         }
 470         spin_unlock(&ocfs2_stack_lock);
 471
 472         return total;
 473 }
 474
 475 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
 476         __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
 477                ocfs2_loaded_cluster_plugins_show, NULL);
 478
 479 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
 480                                                 struct kobj_attribute *attr,
 481                                                 char *buf)
 482 {
 483         ssize_t ret = 0;
 484
 485         spin_lock(&ocfs2_stack_lock);
 486         if (active_stack) {
 487                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 488                                active_stack->sp_name);
 489                 if (ret == PAGE_SIZE)
 490                         ret = -E2BIG;
 491         }
 492         spin_unlock(&ocfs2_stack_lock);
 493
 494         return ret;
 495 }
 496
 497 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
 498         __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
 499                ocfs2_active_cluster_plugin_show, NULL);
 500
 501 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
 502                                         struct kobj_attribute *attr,
 503                                         char *buf)
 504 {
 505         ssize_t ret;
 506         spin_lock(&ocfs2_stack_lock);
 507         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
 508         spin_unlock(&ocfs2_stack_lock);
 509
 510         return ret;
 511 }
 512
 513 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 514                                          struct kobj_attribute *attr,
 515                                          const char *buf, size_t count)
 516 {
 517         size_t len = count;
 518         ssize_t ret;
 519
 520         if (len == 0)
 521                 return len;
 522
 523         if (buf[len - 1] == '\n')
 524                 len--;
 525
 526         if ((len != OCFS2_STACK_LABEL_LEN) ||
 527             (strnlen(buf, len) != len))
 528                 return -EINVAL;
 529
 530         spin_lock(&ocfs2_stack_lock);
 531         if (active_stack) {
 532                 if (!strncmp(buf, cluster_stack_name, len))
 533                         ret = count;
 534                 else
 535                         ret = -EBUSY;
 536         } else {
 537                 memcpy(cluster_stack_name, buf, len);
 538                 ret = count;
 539         }
 540         spin_unlock(&ocfs2_stack_lock);
 541
 542         return ret;
 543 }
 544
 545
 546 static struct kobj_attribute ocfs2_attr_cluster_stack =
 547         __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
 548                ocfs2_cluster_stack_show,
 549                ocfs2_cluster_stack_store);
 550
 551 static struct attribute *ocfs2_attrs[] = {
 552         &ocfs2_attr_max_locking_protocol.attr,
 553         &ocfs2_attr_loaded_cluster_plugins.attr,
 554         &ocfs2_attr_active_cluster_plugin.attr,
 555         &ocfs2_attr_cluster_stack.attr,
 556         NULL,
 557 };
 558
 559 static struct attribute_group ocfs2_attr_group = {
 560         .attrs = ocfs2_attrs,
 561 };
 562
 563 static struct kset *ocfs2_kset;
 564
 565 static void ocfs2_sysfs_exit(void)
 566 {
 567         kset_unregister(ocfs2_kset);
 568 }
 569
 570 static int ocfs2_sysfs_init(void)
 571 {
 572         int ret;
 573
 574         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
 575         if (!ocfs2_kset)
 576                 return -ENOMEM;
 577
 578         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
 579         if (ret)
 580                 goto error;
 581
 582         return 0;
 583
 584 error:
 585         kset_unregister(ocfs2_kset);
 586         return ret;
 587 }
 588
 589 /*
 590  * Sysctl bits
 591  *
 592  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
 593  * make as much sense in a multiple cluster stack world, but it's safer
 594  * and easier to preserve the name.
 595  */
 596
 597 #define FS_OCFS2_NM             1
 598
 599 static ctl_table ocfs2_nm_table[] = {
 600         {
 601                 .ctl_name       = 1,
 602                 .procname       = "hb_ctl_path",
 603                 .data           = ocfs2_hb_ctl_path,
 604                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
 605                 .mode           = 0644,
 606                 .proc_handler   = &proc_dostring,
 607                 .strategy       = &sysctl_string,
 608         },
 609         { .ctl_name = 0 }
 610 };
 611
 612 static ctl_table ocfs2_mod_table[] = {
 613         {
 614                 .ctl_name       = FS_OCFS2_NM,
 615                 .procname       = "nm",
 616                 .data           = NULL,
 617                 .maxlen         = 0,
 618                 .mode           = 0555,
 619                 .child          = ocfs2_nm_table
 620         },
 621         { .ctl_name = 0}
 622 };
 623
 624 static ctl_table ocfs2_kern_table[] = {
 625         {
 626                 .ctl_name       = FS_OCFS2,
 627                 .procname       = "ocfs2",
 628                 .data           = NULL,
 629                 .maxlen         = 0,
 630                 .mode           = 0555,
 631                 .child          = ocfs2_mod_table
 632         },
 633         { .ctl_name = 0}
 634 };
 635
 636 static ctl_table ocfs2_root_table[] = {
 637         {
 638                 .ctl_name       = CTL_FS,
 639                 .procname       = "fs",
 640                 .data           = NULL,
 641                 .maxlen         = 0,
 642                 .mode           = 0555,
 643                 .child          = ocfs2_kern_table
 644         },
 645         { .ctl_name = 0 }
 646 };
 647
 648 static struct ctl_table_header *ocfs2_table_header = NULL;
 649
 650
 651 /*
 652  * Initialization
 653  */
 654
 655 static int __init ocfs2_stack_glue_init(void)
 656 {
 657         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 658
 659         ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
 660         if (!ocfs2_table_header) {
 661                 printk(KERN_ERR
 662                        "ocfs2 stack glue: unable to register sysctl\n");
 663                 return -ENOMEM; /* or something. */
 664         }
 665
 666         return ocfs2_sysfs_init();
 667 }
 668
 669 static void __exit ocfs2_stack_glue_exit(void)
 670 {
 671         lproto = NULL;
 672         ocfs2_sysfs_exit();
 673         if (ocfs2_table_header)
 674                 unregister_sysctl_table(ocfs2_table_header);
 675 }
 676
 677 MODULE_AUTHOR("Oracle");
 678 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
 679 MODULE_LICENSE("GPL");
 680 module_init(ocfs2_stack_glue_init);
 681 module_exit(ocfs2_stack_glue_exit);