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, 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_max_proto = lproto->lp_max_version;
 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_max_proto = lproto->lp_max_version;
 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                    struct ocfs2_dlm_lksb *lksb,
 244                    u32 flags,
 245                    void *name,
 246                    unsigned int namelen)
 247 {
 248         BUG_ON(lproto == NULL);
 249
 250         if (!lksb->lksb_conn)
 251                 lksb->lksb_conn = conn;
 252         else
 253                 BUG_ON(lksb->lksb_conn != conn);
 254         return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
 255                                               name, namelen);
 256 }
 257 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
 258
 259 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
 260                      struct ocfs2_dlm_lksb *lksb,
 261                      u32 flags)
 262 {
 263         BUG_ON(lproto == NULL);
 264         BUG_ON(lksb->lksb_conn == NULL);
 265
 266         return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
 267 }
 268 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
 269
 270 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
 271 {
 272         return active_stack->sp_ops->lock_status(lksb);
 273 }
 274 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
 275
 276 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
 277 {
 278         return active_stack->sp_ops->lvb_valid(lksb);
 279 }
 280 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
 281
 282 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
 283 {
 284         return active_stack->sp_ops->lock_lvb(lksb);
 285 }
 286 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
 287
 288 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
 289 {
 290         active_stack->sp_ops->dump_lksb(lksb);
 291 }
 292 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
 293
 294 int ocfs2_stack_supports_plocks(void)
 295 {
 296         return active_stack && active_stack->sp_ops->plock;
 297 }
 298 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
 299
 300 /*
 301  * ocfs2_plock() can only be safely called if
 302  * ocfs2_stack_supports_plocks() returned true
 303  */
 304 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
 305                 struct file *file, int cmd, struct file_lock *fl)
 306 {
 307         WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
 308         if (active_stack->sp_ops->plock)
 309                 return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
 310         return -EOPNOTSUPP;
 311 }
 312 EXPORT_SYMBOL_GPL(ocfs2_plock);
 313
 314 int ocfs2_cluster_connect(const char *stack_name,
 315                           const char *group,
 316                           int grouplen,
 317                           void (*recovery_handler)(int node_num,
 318                                                    void *recovery_data),
 319                           void *recovery_data,
 320                           struct ocfs2_cluster_connection **conn)
 321 {
 322         int rc = 0;
 323         struct ocfs2_cluster_connection *new_conn;
 324
 325         BUG_ON(group == NULL);
 326         BUG_ON(conn == NULL);
 327         BUG_ON(recovery_handler == NULL);
 328
 329         if (grouplen > GROUP_NAME_MAX) {
 330                 rc = -EINVAL;
 331                 goto out;
 332         }
 333
 334         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
 335                            GFP_KERNEL);
 336         if (!new_conn) {
 337                 rc = -ENOMEM;
 338                 goto out;
 339         }
 340
 341         memcpy(new_conn->cc_name, group, grouplen);
 342         new_conn->cc_namelen = grouplen;
 343         new_conn->cc_recovery_handler = recovery_handler;
 344         new_conn->cc_recovery_data = recovery_data;
 345
 346         new_conn->cc_proto = lproto;
 347         /* Start the new connection at our maximum compatibility level */
 348         new_conn->cc_version = lproto->lp_max_version;
 349
 350         /* This will pin the stack driver if successful */
 351         rc = ocfs2_stack_driver_get(stack_name);
 352         if (rc)
 353                 goto out_free;
 354
 355         rc = active_stack->sp_ops->connect(new_conn);
 356         if (rc) {
 357                 ocfs2_stack_driver_put();
 358                 goto out_free;
 359         }
 360
 361         *conn = new_conn;
 362
 363 out_free:
 364         if (rc)
 365                 kfree(new_conn);
 366
 367 out:
 368         return rc;
 369 }
 370 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
 371
 372 /* If hangup_pending is 0, the stack driver will be dropped */
 373 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 374                              int hangup_pending)
 375 {
 376         int ret;
 377
 378         BUG_ON(conn == NULL);
 379
 380         ret = active_stack->sp_ops->disconnect(conn);
 381
 382         /* XXX Should we free it anyway? */
 383         if (!ret) {
 384                 kfree(conn);
 385                 if (!hangup_pending)
 386                         ocfs2_stack_driver_put();
 387         }
 388
 389         return ret;
 390 }
 391 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 392
 393 /*
 394  * Leave the group for this filesystem.  This is executed by a userspace
 395  * program (stored in ocfs2_hb_ctl_path).
 396  */
 397 static void ocfs2_leave_group(const char *group)
 398 {
 399         int ret;
 400         char *argv[5], *envp[3];
 401
 402         argv[0] = ocfs2_hb_ctl_path;
 403         argv[1] = "-K";
 404         argv[2] = "-u";
 405         argv[3] = (char *)group;
 406         argv[4] = NULL;
 407
 408         /* minimal command environment taken from cpu_run_sbin_hotplug */
 409         envp[0] = "HOME=/";
 410         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 411         envp[2] = NULL;
 412
 413         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 414         if (ret < 0) {
 415                 printk(KERN_ERR
 416                        "ocfs2: Error %d running user helper "
 417                        "\"%s %s %s %s\"\n",
 418                        ret, argv[0], argv[1], argv[2], argv[3]);
 419         }
 420 }
 421
 422 /*
 423  * Hangup is a required post-umount.  ocfs2-tools software expects the
 424  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
 425  * regardless of whether the DLM got started, so we can't do it
 426  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
 427  * the actual work.
 428  */
 429 void ocfs2_cluster_hangup(const char *group, int grouplen)
 430 {
 431         BUG_ON(group == NULL);
 432         BUG_ON(group[grouplen] != '\0');
 433
 434         ocfs2_leave_group(group);
 435
 436         /* cluster_disconnect() was called with hangup_pending==1 */
 437         ocfs2_stack_driver_put();
 438 }
 439 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
 440
 441 int ocfs2_cluster_this_node(unsigned int *node)
 442 {
 443         return active_stack->sp_ops->this_node(node);
 444 }
 445 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
 446
 447
 448 /*
 449  * Sysfs bits
 450  */
 451
 452 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
 453                                                struct kobj_attribute *attr,
 454                                                char *buf)
 455 {
 456         ssize_t ret = 0;
 457
 458         spin_lock(&ocfs2_stack_lock);
 459         if (lproto)
 460                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
 461                                lproto->lp_max_version.pv_major,
 462                                lproto->lp_max_version.pv_minor);
 463         spin_unlock(&ocfs2_stack_lock);
 464
 465         return ret;
 466 }
 467
 468 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
 469         __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
 470                ocfs2_max_locking_protocol_show, NULL);
 471
 472 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
 473                                                  struct kobj_attribute *attr,
 474                                                  char *buf)
 475 {
 476         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
 477         struct ocfs2_stack_plugin *p;
 478
 479         spin_lock(&ocfs2_stack_lock);
 480         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 481                 ret = snprintf(buf, remain, "%s\n",
 482                                p->sp_name);
 483                 if (ret < 0) {
 484                         total = ret;
 485                         break;
 486                 }
 487                 if (ret == remain) {
 488                         /* snprintf() didn't fit */
 489                         total = -E2BIG;
 490                         break;
 491                 }
 492                 total += ret;
 493                 remain -= ret;
 494         }
 495         spin_unlock(&ocfs2_stack_lock);
 496
 497         return total;
 498 }
 499
 500 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
 501         __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
 502                ocfs2_loaded_cluster_plugins_show, NULL);
 503
 504 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
 505                                                 struct kobj_attribute *attr,
 506                                                 char *buf)
 507 {
 508         ssize_t ret = 0;
 509
 510         spin_lock(&ocfs2_stack_lock);
 511         if (active_stack) {
 512                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 513                                active_stack->sp_name);
 514                 if (ret == PAGE_SIZE)
 515                         ret = -E2BIG;
 516         }
 517         spin_unlock(&ocfs2_stack_lock);
 518
 519         return ret;
 520 }
 521
 522 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
 523         __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
 524                ocfs2_active_cluster_plugin_show, NULL);
 525
 526 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
 527                                         struct kobj_attribute *attr,
 528                                         char *buf)
 529 {
 530         ssize_t ret;
 531         spin_lock(&ocfs2_stack_lock);
 532         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
 533         spin_unlock(&ocfs2_stack_lock);
 534
 535         return ret;
 536 }
 537
 538 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 539                                          struct kobj_attribute *attr,
 540                                          const char *buf, size_t count)
 541 {
 542         size_t len = count;
 543         ssize_t ret;
 544
 545         if (len == 0)
 546                 return len;
 547
 548         if (buf[len - 1] == '\n')
 549                 len--;
 550
 551         if ((len != OCFS2_STACK_LABEL_LEN) ||
 552             (strnlen(buf, len) != len))
 553                 return -EINVAL;
 554
 555         spin_lock(&ocfs2_stack_lock);
 556         if (active_stack) {
 557                 if (!strncmp(buf, cluster_stack_name, len))
 558                         ret = count;
 559                 else
 560                         ret = -EBUSY;
 561         } else {
 562                 memcpy(cluster_stack_name, buf, len);
 563                 ret = count;
 564         }
 565         spin_unlock(&ocfs2_stack_lock);
 566
 567         return ret;
 568 }
 569
 570
 571 static struct kobj_attribute ocfs2_attr_cluster_stack =
 572         __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
 573                ocfs2_cluster_stack_show,
 574                ocfs2_cluster_stack_store);
 575
 576 static struct attribute *ocfs2_attrs[] = {
 577         &ocfs2_attr_max_locking_protocol.attr,
 578         &ocfs2_attr_loaded_cluster_plugins.attr,
 579         &ocfs2_attr_active_cluster_plugin.attr,
 580         &ocfs2_attr_cluster_stack.attr,
 581         NULL,
 582 };
 583
 584 static struct attribute_group ocfs2_attr_group = {
 585         .attrs = ocfs2_attrs,
 586 };
 587
 588 static struct kset *ocfs2_kset;
 589
 590 static void ocfs2_sysfs_exit(void)
 591 {
 592         kset_unregister(ocfs2_kset);
 593 }
 594
 595 static int ocfs2_sysfs_init(void)
 596 {
 597         int ret;
 598
 599         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
 600         if (!ocfs2_kset)
 601                 return -ENOMEM;
 602
 603         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
 604         if (ret)
 605                 goto error;
 606
 607         return 0;
 608
 609 error:
 610         kset_unregister(ocfs2_kset);
 611         return ret;
 612 }
 613
 614 /*
 615  * Sysctl bits
 616  *
 617  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
 618  * make as much sense in a multiple cluster stack world, but it's safer
 619  * and easier to preserve the name.
 620  */
 621
 622 #define FS_OCFS2_NM             1
 623
 624 static ctl_table ocfs2_nm_table[] = {
 625         {
 626                 .procname       = "hb_ctl_path",
 627                 .data           = ocfs2_hb_ctl_path,
 628                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
 629                 .mode           = 0644,
 630                 .proc_handler   = proc_dostring,
 631         },
 632         { }
 633 };
 634
 635 static ctl_table ocfs2_mod_table[] = {
 636         {
 637                 .procname       = "nm",
 638                 .data           = NULL,
 639                 .maxlen         = 0,
 640                 .mode           = 0555,
 641                 .child          = ocfs2_nm_table
 642         },
 643         { }
 644 };
 645
 646 static ctl_table ocfs2_kern_table[] = {
 647         {
 648                 .procname       = "ocfs2",
 649                 .data           = NULL,
 650                 .maxlen         = 0,
 651                 .mode           = 0555,
 652                 .child          = ocfs2_mod_table
 653         },
 654         { }
 655 };
 656
 657 static ctl_table ocfs2_root_table[] = {
 658         {
 659                 .procname       = "fs",
 660                 .data           = NULL,
 661                 .maxlen         = 0,
 662                 .mode           = 0555,
 663                 .child          = ocfs2_kern_table
 664         },
 665         { }
 666 };
 667
 668 static struct ctl_table_header *ocfs2_table_header = NULL;
 669
 670
 671 /*
 672  * Initialization
 673  */
 674
 675 static int __init ocfs2_stack_glue_init(void)
 676 {
 677         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 678
 679         ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
 680         if (!ocfs2_table_header) {
 681                 printk(KERN_ERR
 682                        "ocfs2 stack glue: unable to register sysctl\n");
 683                 return -ENOMEM; /* or something. */
 684         }
 685
 686         return ocfs2_sysfs_init();
 687 }
 688
 689 static void __exit ocfs2_stack_glue_exit(void)
 690 {
 691         lproto = NULL;
 692         ocfs2_sysfs_exit();
 693         if (ocfs2_table_header)
 694                 unregister_sysctl_table(ocfs2_table_header);
 695 }
 696
 697 MODULE_AUTHOR("Oracle");
 698 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
 699 MODULE_LICENSE("GPL");
 700 module_init(ocfs2_stack_glue_init);
 701 module_exit(ocfs2_stack_glue_exit);