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         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_stack_supports_plocks(void)
 292 {
 293         return active_stack && active_stack->sp_ops->plock;
 294 }
 295 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
 296
 297 /*
 298  * ocfs2_plock() can only be safely called if
 299  * ocfs2_stack_supports_plocks() returned true
 300  */
 301 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
 302                 struct file *file, int cmd, struct file_lock *fl)
 303 {
 304         WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
 305         if (active_stack->sp_ops->plock)
 306                 return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
 307         return -EOPNOTSUPP;
 308 }
 309 EXPORT_SYMBOL_GPL(ocfs2_plock);
 310
 311 int ocfs2_cluster_connect(const char *stack_name,
 312                           const char *group,
 313                           int grouplen,
 314                           void (*recovery_handler)(int node_num,
 315                                                    void *recovery_data),
 316                           void *recovery_data,
 317                           struct ocfs2_cluster_connection **conn)
 318 {
 319         int rc = 0;
 320         struct ocfs2_cluster_connection *new_conn;
 321
 322         BUG_ON(group == NULL);
 323         BUG_ON(conn == NULL);
 324         BUG_ON(recovery_handler == NULL);
 325
 326         if (grouplen > GROUP_NAME_MAX) {
 327                 rc = -EINVAL;
 328                 goto out;
 329         }
 330
 331         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
 332                            GFP_KERNEL);
 333         if (!new_conn) {
 334                 rc = -ENOMEM;
 335                 goto out;
 336         }
 337
 338         memcpy(new_conn->cc_name, group, grouplen);
 339         new_conn->cc_namelen = grouplen;
 340         new_conn->cc_recovery_handler = recovery_handler;
 341         new_conn->cc_recovery_data = recovery_data;
 342
 343         /* Start the new connection at our maximum compatibility level */
 344         new_conn->cc_version = lproto->lp_max_version;
 345
 346         /* This will pin the stack driver if successful */
 347         rc = ocfs2_stack_driver_get(stack_name);
 348         if (rc)
 349                 goto out_free;
 350
 351         rc = active_stack->sp_ops->connect(new_conn);
 352         if (rc) {
 353                 ocfs2_stack_driver_put();
 354                 goto out_free;
 355         }
 356
 357         *conn = new_conn;
 358
 359 out_free:
 360         if (rc)
 361                 kfree(new_conn);
 362
 363 out:
 364         return rc;
 365 }
 366 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
 367
 368 /* If hangup_pending is 0, the stack driver will be dropped */
 369 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 370                              int hangup_pending)
 371 {
 372         int ret;
 373
 374         BUG_ON(conn == NULL);
 375
 376         ret = active_stack->sp_ops->disconnect(conn);
 377
 378         /* XXX Should we free it anyway? */
 379         if (!ret) {
 380                 kfree(conn);
 381                 if (!hangup_pending)
 382                         ocfs2_stack_driver_put();
 383         }
 384
 385         return ret;
 386 }
 387 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 388
 389 /*
 390  * Leave the group for this filesystem.  This is executed by a userspace
 391  * program (stored in ocfs2_hb_ctl_path).
 392  */
 393 static void ocfs2_leave_group(const char *group)
 394 {
 395         int ret;
 396         char *argv[5], *envp[3];
 397
 398         argv[0] = ocfs2_hb_ctl_path;
 399         argv[1] = "-K";
 400         argv[2] = "-u";
 401         argv[3] = (char *)group;
 402         argv[4] = NULL;
 403
 404         /* minimal command environment taken from cpu_run_sbin_hotplug */
 405         envp[0] = "HOME=/";
 406         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 407         envp[2] = NULL;
 408
 409         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 410         if (ret < 0) {
 411                 printk(KERN_ERR
 412                        "ocfs2: Error %d running user helper "
 413                        "\"%s %s %s %s\"\n",
 414                        ret, argv[0], argv[1], argv[2], argv[3]);
 415         }
 416 }
 417
 418 /*
 419  * Hangup is a required post-umount.  ocfs2-tools software expects the
 420  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
 421  * regardless of whether the DLM got started, so we can't do it
 422  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
 423  * the actual work.
 424  */
 425 void ocfs2_cluster_hangup(const char *group, int grouplen)
 426 {
 427         BUG_ON(group == NULL);
 428         BUG_ON(group[grouplen] != '\0');
 429
 430         ocfs2_leave_group(group);
 431
 432         /* cluster_disconnect() was called with hangup_pending==1 */
 433         ocfs2_stack_driver_put();
 434 }
 435 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
 436
 437 int ocfs2_cluster_this_node(unsigned int *node)
 438 {
 439         return active_stack->sp_ops->this_node(node);
 440 }
 441 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
 442
 443
 444 /*
 445  * Sysfs bits
 446  */
 447
 448 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
 449                                                struct kobj_attribute *attr,
 450                                                char *buf)
 451 {
 452         ssize_t ret = 0;
 453
 454         spin_lock(&ocfs2_stack_lock);
 455         if (lproto)
 456                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
 457                                lproto->lp_max_version.pv_major,
 458                                lproto->lp_max_version.pv_minor);
 459         spin_unlock(&ocfs2_stack_lock);
 460
 461         return ret;
 462 }
 463
 464 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
 465         __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
 466                ocfs2_max_locking_protocol_show, NULL);
 467
 468 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
 469                                                  struct kobj_attribute *attr,
 470                                                  char *buf)
 471 {
 472         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
 473         struct ocfs2_stack_plugin *p;
 474
 475         spin_lock(&ocfs2_stack_lock);
 476         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 477                 ret = snprintf(buf, remain, "%s\n",
 478                                p->sp_name);
 479                 if (ret < 0) {
 480                         total = ret;
 481                         break;
 482                 }
 483                 if (ret == remain) {
 484                         /* snprintf() didn't fit */
 485                         total = -E2BIG;
 486                         break;
 487                 }
 488                 total += ret;
 489                 remain -= ret;
 490         }
 491         spin_unlock(&ocfs2_stack_lock);
 492
 493         return total;
 494 }
 495
 496 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
 497         __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
 498                ocfs2_loaded_cluster_plugins_show, NULL);
 499
 500 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
 501                                                 struct kobj_attribute *attr,
 502                                                 char *buf)
 503 {
 504         ssize_t ret = 0;
 505
 506         spin_lock(&ocfs2_stack_lock);
 507         if (active_stack) {
 508                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 509                                active_stack->sp_name);
 510                 if (ret == PAGE_SIZE)
 511                         ret = -E2BIG;
 512         }
 513         spin_unlock(&ocfs2_stack_lock);
 514
 515         return ret;
 516 }
 517
 518 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
 519         __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
 520                ocfs2_active_cluster_plugin_show, NULL);
 521
 522 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
 523                                         struct kobj_attribute *attr,
 524                                         char *buf)
 525 {
 526         ssize_t ret;
 527         spin_lock(&ocfs2_stack_lock);
 528         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
 529         spin_unlock(&ocfs2_stack_lock);
 530
 531         return ret;
 532 }
 533
 534 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 535                                          struct kobj_attribute *attr,
 536                                          const char *buf, size_t count)
 537 {
 538         size_t len = count;
 539         ssize_t ret;
 540
 541         if (len == 0)
 542                 return len;
 543
 544         if (buf[len - 1] == '\n')
 545                 len--;
 546
 547         if ((len != OCFS2_STACK_LABEL_LEN) ||
 548             (strnlen(buf, len) != len))
 549                 return -EINVAL;
 550
 551         spin_lock(&ocfs2_stack_lock);
 552         if (active_stack) {
 553                 if (!strncmp(buf, cluster_stack_name, len))
 554                         ret = count;
 555                 else
 556                         ret = -EBUSY;
 557         } else {
 558                 memcpy(cluster_stack_name, buf, len);
 559                 ret = count;
 560         }
 561         spin_unlock(&ocfs2_stack_lock);
 562
 563         return ret;
 564 }
 565
 566
 567 static struct kobj_attribute ocfs2_attr_cluster_stack =
 568         __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
 569                ocfs2_cluster_stack_show,
 570                ocfs2_cluster_stack_store);
 571
 572 static struct attribute *ocfs2_attrs[] = {
 573         &ocfs2_attr_max_locking_protocol.attr,
 574         &ocfs2_attr_loaded_cluster_plugins.attr,
 575         &ocfs2_attr_active_cluster_plugin.attr,
 576         &ocfs2_attr_cluster_stack.attr,
 577         NULL,
 578 };
 579
 580 static struct attribute_group ocfs2_attr_group = {
 581         .attrs = ocfs2_attrs,
 582 };
 583
 584 static struct kset *ocfs2_kset;
 585
 586 static void ocfs2_sysfs_exit(void)
 587 {
 588         kset_unregister(ocfs2_kset);
 589 }
 590
 591 static int ocfs2_sysfs_init(void)
 592 {
 593         int ret;
 594
 595         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
 596         if (!ocfs2_kset)
 597                 return -ENOMEM;
 598
 599         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
 600         if (ret)
 601                 goto error;
 602
 603         return 0;
 604
 605 error:
 606         kset_unregister(ocfs2_kset);
 607         return ret;
 608 }
 609
 610 /*
 611  * Sysctl bits
 612  *
 613  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
 614  * make as much sense in a multiple cluster stack world, but it's safer
 615  * and easier to preserve the name.
 616  */
 617
 618 #define FS_OCFS2_NM             1
 619
 620 static ctl_table ocfs2_nm_table[] = {
 621         {
 622                 .ctl_name       = 1,
 623                 .procname       = "hb_ctl_path",
 624                 .data           = ocfs2_hb_ctl_path,
 625                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
 626                 .mode           = 0644,
 627                 .proc_handler   = &proc_dostring,
 628                 .strategy       = &sysctl_string,
 629         },
 630         { .ctl_name = 0 }
 631 };
 632
 633 static ctl_table ocfs2_mod_table[] = {
 634         {
 635                 .ctl_name       = FS_OCFS2_NM,
 636                 .procname       = "nm",
 637                 .data           = NULL,
 638                 .maxlen         = 0,
 639                 .mode           = 0555,
 640                 .child          = ocfs2_nm_table
 641         },
 642         { .ctl_name = 0}
 643 };
 644
 645 static ctl_table ocfs2_kern_table[] = {
 646         {
 647                 .ctl_name       = FS_OCFS2,
 648                 .procname       = "ocfs2",
 649                 .data           = NULL,
 650                 .maxlen         = 0,
 651                 .mode           = 0555,
 652                 .child          = ocfs2_mod_table
 653         },
 654         { .ctl_name = 0}
 655 };
 656
 657 static ctl_table ocfs2_root_table[] = {
 658         {
 659                 .ctl_name       = CTL_FS,
 660                 .procname       = "fs",
 661                 .data           = NULL,
 662                 .maxlen         = 0,
 663                 .mode           = 0555,
 664                 .child          = ocfs2_kern_table
 665         },
 666         { .ctl_name = 0 }
 667 };
 668
 669 static struct ctl_table_header *ocfs2_table_header = NULL;
 670
 671
 672 /*
 673  * Initialization
 674  */
 675
 676 static int __init ocfs2_stack_glue_init(void)
 677 {
 678         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 679
 680         ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
 681         if (!ocfs2_table_header) {
 682                 printk(KERN_ERR
 683                        "ocfs2 stack glue: unable to register sysctl\n");
 684                 return -ENOMEM; /* or something. */
 685         }
 686
 687         return ocfs2_sysfs_init();
 688 }
 689
 690 static void __exit ocfs2_stack_glue_exit(void)
 691 {
 692         lproto = NULL;
 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 cluter stack glue layer");
 700 MODULE_LICENSE("GPL");
 701 module_init(ocfs2_stack_glue_init);
 702 module_exit(ocfs2_stack_glue_exit);