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