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   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, 2009 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 no argument
 237  * for the ast and bast functions.  They will pass the lksb to the ast
 238  * and bast.  The caller can wrap the lksb with their own structure to
 239  * get more information.
 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 {
 248         BUG_ON(lproto == NULL);
 249
 250         return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
 251                                               name, namelen);
 252 }
 253 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
 254
 255 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
 256                      union ocfs2_dlm_lksb *lksb,
 257                      u32 flags)
 258 {
 259         BUG_ON(lproto == NULL);
 260
 261         return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
 262 }
 263 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
 264
 265 int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
 266 {
 267         return active_stack->sp_ops->lock_status(lksb);
 268 }
 269 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
 270
 271 int ocfs2_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb)
 272 {
 273         return active_stack->sp_ops->lvb_valid(lksb);
 274 }
 275 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
 276
 277 void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb)
 278 {
 279         return active_stack->sp_ops->lock_lvb(lksb);
 280 }
 281 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
 282
 283 void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
 284 {
 285         active_stack->sp_ops->dump_lksb(lksb);
 286 }
 287 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
 288
 289 int ocfs2_stack_supports_plocks(void)
 290 {
 291         return active_stack && active_stack->sp_ops->plock;
 292 }
 293 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
 294
 295 /*
 296  * ocfs2_plock() can only be safely called if
 297  * ocfs2_stack_supports_plocks() returned true
 298  */
 299 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
 300                 struct file *file, int cmd, struct file_lock *fl)
 301 {
 302         WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
 303         if (active_stack->sp_ops->plock)
 304                 return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
 305         return -EOPNOTSUPP;
 306 }
 307 EXPORT_SYMBOL_GPL(ocfs2_plock);
 308
 309 int ocfs2_cluster_connect(const char *stack_name,
 310                           const char *group,
 311                           int grouplen,
 312                           void (*recovery_handler)(int node_num,
 313                                                    void *recovery_data),
 314                           void *recovery_data,
 315                           struct ocfs2_cluster_connection **conn)
 316 {
 317         int rc = 0;
 318         struct ocfs2_cluster_connection *new_conn;
 319
 320         BUG_ON(group == NULL);
 321         BUG_ON(conn == NULL);
 322         BUG_ON(recovery_handler == NULL);
 323
 324         if (grouplen > GROUP_NAME_MAX) {
 325                 rc = -EINVAL;
 326                 goto out;
 327         }
 328
 329         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
 330                            GFP_KERNEL);
 331         if (!new_conn) {
 332                 rc = -ENOMEM;
 333                 goto out;
 334         }
 335
 336         memcpy(new_conn->cc_name, group, grouplen);
 337         new_conn->cc_namelen = grouplen;
 338         new_conn->cc_recovery_handler = recovery_handler;
 339         new_conn->cc_recovery_data = recovery_data;
 340
 341         /* Start the new connection at our maximum compatibility level */
 342         new_conn->cc_version = lproto->lp_max_version;
 343
 344         /* This will pin the stack driver if successful */
 345         rc = ocfs2_stack_driver_get(stack_name);
 346         if (rc)
 347                 goto out_free;
 348
 349         rc = active_stack->sp_ops->connect(new_conn);
 350         if (rc) {
 351                 ocfs2_stack_driver_put();
 352                 goto out_free;
 353         }
 354
 355         *conn = new_conn;
 356
 357 out_free:
 358         if (rc)
 359                 kfree(new_conn);
 360
 361 out:
 362         return rc;
 363 }
 364 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
 365
 366 /* If hangup_pending is 0, the stack driver will be dropped */
 367 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 368                              int hangup_pending)
 369 {
 370         int ret;
 371
 372         BUG_ON(conn == NULL);
 373
 374         ret = active_stack->sp_ops->disconnect(conn);
 375
 376         /* XXX Should we free it anyway? */
 377         if (!ret) {
 378                 kfree(conn);
 379                 if (!hangup_pending)
 380                         ocfs2_stack_driver_put();
 381         }
 382
 383         return ret;
 384 }
 385 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 386
 387 /*
 388  * Leave the group for this filesystem.  This is executed by a userspace
 389  * program (stored in ocfs2_hb_ctl_path).
 390  */
 391 static void ocfs2_leave_group(const char *group)
 392 {
 393         int ret;
 394         char *argv[5], *envp[3];
 395
 396         argv[0] = ocfs2_hb_ctl_path;
 397         argv[1] = "-K";
 398         argv[2] = "-u";
 399         argv[3] = (char *)group;
 400         argv[4] = NULL;
 401
 402         /* minimal command environment taken from cpu_run_sbin_hotplug */
 403         envp[0] = "HOME=/";
 404         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 405         envp[2] = NULL;
 406
 407         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 408         if (ret < 0) {
 409                 printk(KERN_ERR
 410                        "ocfs2: Error %d running user helper "
 411                        "\"%s %s %s %s\"\n",
 412                        ret, argv[0], argv[1], argv[2], argv[3]);
 413         }
 414 }
 415
 416 /*
 417  * Hangup is a required post-umount.  ocfs2-tools software expects the
 418  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
 419  * regardless of whether the DLM got started, so we can't do it
 420  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
 421  * the actual work.
 422  */
 423 void ocfs2_cluster_hangup(const char *group, int grouplen)
 424 {
 425         BUG_ON(group == NULL);
 426         BUG_ON(group[grouplen] != '\0');
 427
 428         ocfs2_leave_group(group);
 429
 430         /* cluster_disconnect() was called with hangup_pending==1 */
 431         ocfs2_stack_driver_put();
 432 }
 433 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
 434
 435 int ocfs2_cluster_this_node(unsigned int *node)
 436 {
 437         return active_stack->sp_ops->this_node(node);
 438 }
 439 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
 440
 441
 442 /*
 443  * Sysfs bits
 444  */
 445
 446 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
 447                                                struct kobj_attribute *attr,
 448                                                char *buf)
 449 {
 450         ssize_t ret = 0;
 451
 452         spin_lock(&ocfs2_stack_lock);
 453         if (lproto)
 454                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
 455                                lproto->lp_max_version.pv_major,
 456                                lproto->lp_max_version.pv_minor);
 457         spin_unlock(&ocfs2_stack_lock);
 458
 459         return ret;
 460 }
 461
 462 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
 463         __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
 464                ocfs2_max_locking_protocol_show, NULL);
 465
 466 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
 467                                                  struct kobj_attribute *attr,
 468                                                  char *buf)
 469 {
 470         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
 471         struct ocfs2_stack_plugin *p;
 472
 473         spin_lock(&ocfs2_stack_lock);
 474         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 475                 ret = snprintf(buf, remain, "%s\n",
 476                                p->sp_name);
 477                 if (ret < 0) {
 478                         total = ret;
 479                         break;
 480                 }
 481                 if (ret == remain) {
 482                         /* snprintf() didn't fit */
 483                         total = -E2BIG;
 484                         break;
 485                 }
 486                 total += ret;
 487                 remain -= ret;
 488         }
 489         spin_unlock(&ocfs2_stack_lock);
 490
 491         return total;
 492 }
 493
 494 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
 495         __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
 496                ocfs2_loaded_cluster_plugins_show, NULL);
 497
 498 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
 499                                                 struct kobj_attribute *attr,
 500                                                 char *buf)
 501 {
 502         ssize_t ret = 0;
 503
 504         spin_lock(&ocfs2_stack_lock);
 505         if (active_stack) {
 506                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 507                                active_stack->sp_name);
 508                 if (ret == PAGE_SIZE)
 509                         ret = -E2BIG;
 510         }
 511         spin_unlock(&ocfs2_stack_lock);
 512
 513         return ret;
 514 }
 515
 516 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
 517         __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
 518                ocfs2_active_cluster_plugin_show, NULL);
 519
 520 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
 521                                         struct kobj_attribute *attr,
 522                                         char *buf)
 523 {
 524         ssize_t ret;
 525         spin_lock(&ocfs2_stack_lock);
 526         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
 527         spin_unlock(&ocfs2_stack_lock);
 528
 529         return ret;
 530 }
 531
 532 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 533                                          struct kobj_attribute *attr,
 534                                          const char *buf, size_t count)
 535 {
 536         size_t len = count;
 537         ssize_t ret;
 538
 539         if (len == 0)
 540                 return len;
 541
 542         if (buf[len - 1] == '\n')
 543                 len--;
 544
 545         if ((len != OCFS2_STACK_LABEL_LEN) ||
 546             (strnlen(buf, len) != len))
 547                 return -EINVAL;
 548
 549         spin_lock(&ocfs2_stack_lock);
 550         if (active_stack) {
 551                 if (!strncmp(buf, cluster_stack_name, len))
 552                         ret = count;
 553                 else
 554                         ret = -EBUSY;
 555         } else {
 556                 memcpy(cluster_stack_name, buf, len);
 557                 ret = count;
 558         }
 559         spin_unlock(&ocfs2_stack_lock);
 560
 561         return ret;
 562 }
 563
 564
 565 static struct kobj_attribute ocfs2_attr_cluster_stack =
 566         __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
 567                ocfs2_cluster_stack_show,
 568                ocfs2_cluster_stack_store);
 569
 570 static struct attribute *ocfs2_attrs[] = {
 571         &ocfs2_attr_max_locking_protocol.attr,
 572         &ocfs2_attr_loaded_cluster_plugins.attr,
 573         &ocfs2_attr_active_cluster_plugin.attr,
 574         &ocfs2_attr_cluster_stack.attr,
 575         NULL,
 576 };
 577
 578 static struct attribute_group ocfs2_attr_group = {
 579         .attrs = ocfs2_attrs,
 580 };
 581
 582 static struct kset *ocfs2_kset;
 583
 584 static void ocfs2_sysfs_exit(void)
 585 {
 586         kset_unregister(ocfs2_kset);
 587 }
 588
 589 static int ocfs2_sysfs_init(void)
 590 {
 591         int ret;
 592
 593         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
 594         if (!ocfs2_kset)
 595                 return -ENOMEM;
 596
 597         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
 598         if (ret)
 599                 goto error;
 600
 601         return 0;
 602
 603 error:
 604         kset_unregister(ocfs2_kset);
 605         return ret;
 606 }
 607
 608 /*
 609  * Sysctl bits
 610  *
 611  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
 612  * make as much sense in a multiple cluster stack world, but it's safer
 613  * and easier to preserve the name.
 614  */
 615
 616 #define FS_OCFS2_NM             1
 617
 618 static ctl_table ocfs2_nm_table[] = {
 619         {
 620                 .procname       = "hb_ctl_path",
 621                 .data           = ocfs2_hb_ctl_path,
 622                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
 623                 .mode           = 0644,
 624                 .proc_handler   = proc_dostring,
 625         },
 626         { }
 627 };
 628
 629 static ctl_table ocfs2_mod_table[] = {
 630         {
 631                 .procname       = "nm",
 632                 .data           = NULL,
 633                 .maxlen         = 0,
 634                 .mode           = 0555,
 635                 .child          = ocfs2_nm_table
 636         },
 637         { }
 638 };
 639
 640 static ctl_table ocfs2_kern_table[] = {
 641         {
 642                 .procname       = "ocfs2",
 643                 .data           = NULL,
 644                 .maxlen         = 0,
 645                 .mode           = 0555,
 646                 .child          = ocfs2_mod_table
 647         },
 648         { }
 649 };
 650
 651 static ctl_table ocfs2_root_table[] = {
 652         {
 653                 .procname       = "fs",
 654                 .data           = NULL,
 655                 .maxlen         = 0,
 656                 .mode           = 0555,
 657                 .child          = ocfs2_kern_table
 658         },
 659         { }
 660 };
 661
 662 static struct ctl_table_header *ocfs2_table_header = NULL;
 663
 664
 665 /*
 666  * Initialization
 667  */
 668
 669 static int __init ocfs2_stack_glue_init(void)
 670 {
 671         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 672
 673         ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
 674         if (!ocfs2_table_header) {
 675                 printk(KERN_ERR
 676                        "ocfs2 stack glue: unable to register sysctl\n");
 677                 return -ENOMEM; /* or something. */
 678         }
 679
 680         return ocfs2_sysfs_init();
 681 }
 682
 683 static void __exit ocfs2_stack_glue_exit(void)
 684 {
 685         lproto = NULL;
 686         ocfs2_sysfs_exit();
 687         if (ocfs2_table_header)
 688                 unregister_sysctl_table(ocfs2_table_header);
 689 }
 690
 691 MODULE_AUTHOR("Oracle");
 692 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
 693 MODULE_LICENSE("GPL");
 694 module_init(ocfs2_stack_glue_init);
 695 module_exit(ocfs2_stack_glue_exit);