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_protocol_version locking_max_version;
  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 inline int ocfs2_is_o2cb_active(void)
  52 {
  53         return !strcmp(active_stack->sp_name, OCFS2_STACK_PLUGIN_O2CB);
  54 }
  55 EXPORT_SYMBOL_GPL(ocfs2_is_o2cb_active);
  56
  57 static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
  58 {
  59         struct ocfs2_stack_plugin *p;
  60
  61         assert_spin_locked(&ocfs2_stack_lock);
  62
  63         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
  64                 if (!strcmp(p->sp_name, name))
  65                         return p;
  66         }
  67
  68         return NULL;
  69 }
  70
  71 static int ocfs2_stack_driver_request(const char *stack_name,
  72                                       const char *plugin_name)
  73 {
  74         int rc;
  75         struct ocfs2_stack_plugin *p;
  76
  77         spin_lock(&ocfs2_stack_lock);
  78
  79         /*
  80          * If the stack passed by the filesystem isn't the selected one,
  81          * we can't continue.
  82          */
  83         if (strcmp(stack_name, cluster_stack_name)) {
  84                 rc = -EBUSY;
  85                 goto out;
  86         }
  87
  88         if (active_stack) {
  89                 /*
  90                  * If the active stack isn't the one we want, it cannot
  91                  * be selected right now.
  92                  */
  93                 if (!strcmp(active_stack->sp_name, plugin_name))
  94                         rc = 0;
  95                 else
  96                         rc = -EBUSY;
  97                 goto out;
  98         }
  99
 100         p = ocfs2_stack_lookup(plugin_name);
 101         if (!p || !try_module_get(p->sp_owner)) {
 102                 rc = -ENOENT;
 103                 goto out;
 104         }
 105
 106         active_stack = p;
 107         rc = 0;
 108
 109 out:
 110         /* If we found it, pin it */
 111         if (!rc)
 112                 active_stack->sp_count++;
 113
 114         spin_unlock(&ocfs2_stack_lock);
 115         return rc;
 116 }
 117
 118 /*
 119  * This function looks up the appropriate stack and makes it active.  If
 120  * there is no stack, it tries to load it.  It will fail if the stack still
 121  * cannot be found.  It will also fail if a different stack is in use.
 122  */
 123 static int ocfs2_stack_driver_get(const char *stack_name)
 124 {
 125         int rc;
 126         char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
 127
 128         /*
 129          * Classic stack does not pass in a stack name.  This is
 130          * compatible with older tools as well.
 131          */
 132         if (!stack_name || !*stack_name)
 133                 stack_name = OCFS2_STACK_PLUGIN_O2CB;
 134
 135         if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
 136                 printk(KERN_ERR
 137                        "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
 138                        stack_name);
 139                 return -EINVAL;
 140         }
 141
 142         /* Anything that isn't the classic stack is a user stack */
 143         if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
 144                 plugin_name = OCFS2_STACK_PLUGIN_USER;
 145
 146         rc = ocfs2_stack_driver_request(stack_name, plugin_name);
 147         if (rc == -ENOENT) {
 148                 request_module("ocfs2_stack_%s", plugin_name);
 149                 rc = ocfs2_stack_driver_request(stack_name, plugin_name);
 150         }
 151
 152         if (rc == -ENOENT) {
 153                 printk(KERN_ERR
 154                        "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
 155                        plugin_name);
 156         } else if (rc == -EBUSY) {
 157                 printk(KERN_ERR
 158                        "ocfs2: A different cluster stack is in use\n");
 159         }
 160
 161         return rc;
 162 }
 163
 164 static void ocfs2_stack_driver_put(void)
 165 {
 166         spin_lock(&ocfs2_stack_lock);
 167         BUG_ON(active_stack == NULL);
 168         BUG_ON(active_stack->sp_count == 0);
 169
 170         active_stack->sp_count--;
 171         if (!active_stack->sp_count) {
 172                 module_put(active_stack->sp_owner);
 173                 active_stack = NULL;
 174         }
 175         spin_unlock(&ocfs2_stack_lock);
 176 }
 177
 178 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
 179 {
 180         int rc;
 181
 182         spin_lock(&ocfs2_stack_lock);
 183         if (!ocfs2_stack_lookup(plugin->sp_name)) {
 184                 plugin->sp_count = 0;
 185                 plugin->sp_max_proto = locking_max_version;
 186                 list_add(&plugin->sp_list, &ocfs2_stack_list);
 187                 printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
 188                        plugin->sp_name);
 189                 rc = 0;
 190         } else {
 191                 printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
 192                        plugin->sp_name);
 193                 rc = -EEXIST;
 194         }
 195         spin_unlock(&ocfs2_stack_lock);
 196
 197         return rc;
 198 }
 199 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
 200
 201 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
 202 {
 203         struct ocfs2_stack_plugin *p;
 204
 205         spin_lock(&ocfs2_stack_lock);
 206         p = ocfs2_stack_lookup(plugin->sp_name);
 207         if (p) {
 208                 BUG_ON(p != plugin);
 209                 BUG_ON(plugin == active_stack);
 210                 BUG_ON(plugin->sp_count != 0);
 211                 list_del_init(&plugin->sp_list);
 212                 printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
 213                        plugin->sp_name);
 214         } else {
 215                 printk(KERN_ERR "Stack \"%s\" is not registered\n",
 216                        plugin->sp_name);
 217         }
 218         spin_unlock(&ocfs2_stack_lock);
 219 }
 220 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
 221
 222 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
 223 {
 224         struct ocfs2_stack_plugin *p;
 225
 226         spin_lock(&ocfs2_stack_lock);
 227         if (memcmp(max_proto, &locking_max_version,
 228                    sizeof(struct ocfs2_protocol_version))) {
 229                 BUG_ON(locking_max_version.pv_major != 0);
 230
 231                 locking_max_version = *max_proto;
 232                 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 233                         p->sp_max_proto = locking_max_version;
 234                 }
 235         }
 236         spin_unlock(&ocfs2_stack_lock);
 237 }
 238 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
 239
 240
 241 /*
 242  * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
 243  * for the ast and bast functions.  They will pass the lksb to the ast
 244  * and bast.  The caller can wrap the lksb with their own structure to
 245  * get more information.
 246  */
 247 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
 248                    int mode,
 249                    struct ocfs2_dlm_lksb *lksb,
 250                    u32 flags,
 251                    void *name,
 252                    unsigned int namelen)
 253 {
 254         if (!lksb->lksb_conn)
 255                 lksb->lksb_conn = conn;
 256         else
 257                 BUG_ON(lksb->lksb_conn != conn);
 258         return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
 259                                               name, namelen);
 260 }
 261 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
 262
 263 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
 264                      struct ocfs2_dlm_lksb *lksb,
 265                      u32 flags)
 266 {
 267         BUG_ON(lksb->lksb_conn == NULL);
 268
 269         return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
 270 }
 271 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
 272
 273 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
 274 {
 275         return active_stack->sp_ops->lock_status(lksb);
 276 }
 277 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
 278
 279 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
 280 {
 281         return active_stack->sp_ops->lvb_valid(lksb);
 282 }
 283 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
 284
 285 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
 286 {
 287         return active_stack->sp_ops->lock_lvb(lksb);
 288 }
 289 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
 290
 291 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
 292 {
 293         active_stack->sp_ops->dump_lksb(lksb);
 294 }
 295 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
 296
 297 int ocfs2_stack_supports_plocks(void)
 298 {
 299         return active_stack && active_stack->sp_ops->plock;
 300 }
 301 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
 302
 303 /*
 304  * ocfs2_plock() can only be safely called if
 305  * ocfs2_stack_supports_plocks() returned true
 306  */
 307 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
 308                 struct file *file, int cmd, struct file_lock *fl)
 309 {
 310         WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
 311         if (active_stack->sp_ops->plock)
 312                 return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
 313         return -EOPNOTSUPP;
 314 }
 315 EXPORT_SYMBOL_GPL(ocfs2_plock);
 316
 317 int ocfs2_cluster_connect(const char *stack_name,
 318                           const char *group,
 319                           int grouplen,
 320                           struct ocfs2_locking_protocol *lproto,
 321                           void (*recovery_handler)(int node_num,
 322                                                    void *recovery_data),
 323                           void *recovery_data,
 324                           struct ocfs2_cluster_connection **conn)
 325 {
 326         int rc = 0;
 327         struct ocfs2_cluster_connection *new_conn;
 328
 329         BUG_ON(group == NULL);
 330         BUG_ON(conn == NULL);
 331         BUG_ON(recovery_handler == NULL);
 332
 333         if (grouplen > GROUP_NAME_MAX) {
 334                 rc = -EINVAL;
 335                 goto out;
 336         }
 337
 338         if (memcmp(&lproto->lp_max_version, &locking_max_version,
 339                    sizeof(struct ocfs2_protocol_version))) {
 340                 rc = -EINVAL;
 341                 goto out;
 342         }
 343
 344         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
 345                            GFP_KERNEL);
 346         if (!new_conn) {
 347                 rc = -ENOMEM;
 348                 goto out;
 349         }
 350
 351         memcpy(new_conn->cc_name, group, grouplen);
 352         new_conn->cc_namelen = grouplen;
 353         new_conn->cc_recovery_handler = recovery_handler;
 354         new_conn->cc_recovery_data = recovery_data;
 355
 356         new_conn->cc_proto = lproto;
 357         /* Start the new connection at our maximum compatibility level */
 358         new_conn->cc_version = lproto->lp_max_version;
 359
 360         /* This will pin the stack driver if successful */
 361         rc = ocfs2_stack_driver_get(stack_name);
 362         if (rc)
 363                 goto out_free;
 364
 365         rc = active_stack->sp_ops->connect(new_conn);
 366         if (rc) {
 367                 ocfs2_stack_driver_put();
 368                 goto out_free;
 369         }
 370
 371         *conn = new_conn;
 372
 373 out_free:
 374         if (rc)
 375                 kfree(new_conn);
 376
 377 out:
 378         return rc;
 379 }
 380 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
 381
 382 /* The caller will ensure all nodes have the same cluster stack */
 383 int ocfs2_cluster_connect_agnostic(const char *group,
 384                                    int grouplen,
 385                                    struct ocfs2_locking_protocol *lproto,
 386                                    void (*recovery_handler)(int node_num,
 387                                                             void *recovery_data),
 388                                    void *recovery_data,
 389                                    struct ocfs2_cluster_connection **conn)
 390 {
 391         char *stack_name = NULL;
 392
 393         if (cluster_stack_name[0])
 394                 stack_name = cluster_stack_name;
 395         return ocfs2_cluster_connect(stack_name, group, grouplen, lproto,
 396                                      recovery_handler, recovery_data, conn);
 397 }
 398 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
 399
 400 /* If hangup_pending is 0, the stack driver will be dropped */
 401 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 402                              int hangup_pending)
 403 {
 404         int ret;
 405
 406         BUG_ON(conn == NULL);
 407
 408         ret = active_stack->sp_ops->disconnect(conn);
 409
 410         /* XXX Should we free it anyway? */
 411         if (!ret) {
 412                 kfree(conn);
 413                 if (!hangup_pending)
 414                         ocfs2_stack_driver_put();
 415         }
 416
 417         return ret;
 418 }
 419 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 420
 421 /*
 422  * Leave the group for this filesystem.  This is executed by a userspace
 423  * program (stored in ocfs2_hb_ctl_path).
 424  */
 425 static void ocfs2_leave_group(const char *group)
 426 {
 427         int ret;
 428         char *argv[5], *envp[3];
 429
 430         argv[0] = ocfs2_hb_ctl_path;
 431         argv[1] = "-K";
 432         argv[2] = "-u";
 433         argv[3] = (char *)group;
 434         argv[4] = NULL;
 435
 436         /* minimal command environment taken from cpu_run_sbin_hotplug */
 437         envp[0] = "HOME=/";
 438         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 439         envp[2] = NULL;
 440
 441         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 442         if (ret < 0) {
 443                 printk(KERN_ERR
 444                        "ocfs2: Error %d running user helper "
 445                        "\"%s %s %s %s\"\n",
 446                        ret, argv[0], argv[1], argv[2], argv[3]);
 447         }
 448 }
 449
 450 /*
 451  * Hangup is a required post-umount.  ocfs2-tools software expects the
 452  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
 453  * regardless of whether the DLM got started, so we can't do it
 454  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
 455  * the actual work.
 456  */
 457 void ocfs2_cluster_hangup(const char *group, int grouplen)
 458 {
 459         BUG_ON(group == NULL);
 460         BUG_ON(group[grouplen] != '\0');
 461
 462         ocfs2_leave_group(group);
 463
 464         /* cluster_disconnect() was called with hangup_pending==1 */
 465         ocfs2_stack_driver_put();
 466 }
 467 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
 468
 469 int ocfs2_cluster_this_node(unsigned int *node)
 470 {
 471         return active_stack->sp_ops->this_node(node);
 472 }
 473 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
 474
 475
 476 /*
 477  * Sysfs bits
 478  */
 479
 480 static ssize_t ocfs2_max_locking_protocol_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 (locking_max_version.pv_major)
 488                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
 489                                locking_max_version.pv_major,
 490                                locking_max_version.pv_minor);
 491         spin_unlock(&ocfs2_stack_lock);
 492
 493         return ret;
 494 }
 495
 496 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
 497         __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
 498                ocfs2_max_locking_protocol_show, NULL);
 499
 500 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
 501                                                  struct kobj_attribute *attr,
 502                                                  char *buf)
 503 {
 504         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
 505         struct ocfs2_stack_plugin *p;
 506
 507         spin_lock(&ocfs2_stack_lock);
 508         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 509                 ret = snprintf(buf, remain, "%s\n",
 510                                p->sp_name);
 511                 if (ret < 0) {
 512                         total = ret;
 513                         break;
 514                 }
 515                 if (ret == remain) {
 516                         /* snprintf() didn't fit */
 517                         total = -E2BIG;
 518                         break;
 519                 }
 520                 total += ret;
 521                 remain -= ret;
 522         }
 523         spin_unlock(&ocfs2_stack_lock);
 524
 525         return total;
 526 }
 527
 528 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
 529         __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
 530                ocfs2_loaded_cluster_plugins_show, NULL);
 531
 532 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
 533                                                 struct kobj_attribute *attr,
 534                                                 char *buf)
 535 {
 536         ssize_t ret = 0;
 537
 538         spin_lock(&ocfs2_stack_lock);
 539         if (active_stack) {
 540                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 541                                active_stack->sp_name);
 542                 if (ret == PAGE_SIZE)
 543                         ret = -E2BIG;
 544         }
 545         spin_unlock(&ocfs2_stack_lock);
 546
 547         return ret;
 548 }
 549
 550 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
 551         __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
 552                ocfs2_active_cluster_plugin_show, NULL);
 553
 554 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
 555                                         struct kobj_attribute *attr,
 556                                         char *buf)
 557 {
 558         ssize_t ret;
 559         spin_lock(&ocfs2_stack_lock);
 560         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
 561         spin_unlock(&ocfs2_stack_lock);
 562
 563         return ret;
 564 }
 565
 566 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 567                                          struct kobj_attribute *attr,
 568                                          const char *buf, size_t count)
 569 {
 570         size_t len = count;
 571         ssize_t ret;
 572
 573         if (len == 0)
 574                 return len;
 575
 576         if (buf[len - 1] == '\n')
 577                 len--;
 578
 579         if ((len != OCFS2_STACK_LABEL_LEN) ||
 580             (strnlen(buf, len) != len))
 581                 return -EINVAL;
 582
 583         spin_lock(&ocfs2_stack_lock);
 584         if (active_stack) {
 585                 if (!strncmp(buf, cluster_stack_name, len))
 586                         ret = count;
 587                 else
 588                         ret = -EBUSY;
 589         } else {
 590                 memcpy(cluster_stack_name, buf, len);
 591                 ret = count;
 592         }
 593         spin_unlock(&ocfs2_stack_lock);
 594
 595         return ret;
 596 }
 597
 598
 599 static struct kobj_attribute ocfs2_attr_cluster_stack =
 600         __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
 601                ocfs2_cluster_stack_show,
 602                ocfs2_cluster_stack_store);
 603
 604 static struct attribute *ocfs2_attrs[] = {
 605         &ocfs2_attr_max_locking_protocol.attr,
 606         &ocfs2_attr_loaded_cluster_plugins.attr,
 607         &ocfs2_attr_active_cluster_plugin.attr,
 608         &ocfs2_attr_cluster_stack.attr,
 609         NULL,
 610 };
 611
 612 static struct attribute_group ocfs2_attr_group = {
 613         .attrs = ocfs2_attrs,
 614 };
 615
 616 static struct kset *ocfs2_kset;
 617
 618 static void ocfs2_sysfs_exit(void)
 619 {
 620         kset_unregister(ocfs2_kset);
 621 }
 622
 623 static int ocfs2_sysfs_init(void)
 624 {
 625         int ret;
 626
 627         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
 628         if (!ocfs2_kset)
 629                 return -ENOMEM;
 630
 631         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
 632         if (ret)
 633                 goto error;
 634
 635         return 0;
 636
 637 error:
 638         kset_unregister(ocfs2_kset);
 639         return ret;
 640 }
 641
 642 /*
 643  * Sysctl bits
 644  *
 645  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
 646  * make as much sense in a multiple cluster stack world, but it's safer
 647  * and easier to preserve the name.
 648  */
 649
 650 #define FS_OCFS2_NM             1
 651
 652 static ctl_table ocfs2_nm_table[] = {
 653         {
 654                 .procname       = "hb_ctl_path",
 655                 .data           = ocfs2_hb_ctl_path,
 656                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
 657                 .mode           = 0644,
 658                 .proc_handler   = proc_dostring,
 659         },
 660         { }
 661 };
 662
 663 static ctl_table ocfs2_mod_table[] = {
 664         {
 665                 .procname       = "nm",
 666                 .data           = NULL,
 667                 .maxlen         = 0,
 668                 .mode           = 0555,
 669                 .child          = ocfs2_nm_table
 670         },
 671         { }
 672 };
 673
 674 static ctl_table ocfs2_kern_table[] = {
 675         {
 676                 .procname       = "ocfs2",
 677                 .data           = NULL,
 678                 .maxlen         = 0,
 679                 .mode           = 0555,
 680                 .child          = ocfs2_mod_table
 681         },
 682         { }
 683 };
 684
 685 static ctl_table ocfs2_root_table[] = {
 686         {
 687                 .procname       = "fs",
 688                 .data           = NULL,
 689                 .maxlen         = 0,
 690                 .mode           = 0555,
 691                 .child          = ocfs2_kern_table
 692         },
 693         { }
 694 };
 695
 696 static struct ctl_table_header *ocfs2_table_header = NULL;
 697
 698
 699 /*
 700  * Initialization
 701  */
 702
 703 static int __init ocfs2_stack_glue_init(void)
 704 {
 705         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 706
 707         ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
 708         if (!ocfs2_table_header) {
 709                 printk(KERN_ERR
 710                        "ocfs2 stack glue: unable to register sysctl\n");
 711                 return -ENOMEM; /* or something. */
 712         }
 713
 714         return ocfs2_sysfs_init();
 715 }
 716
 717 static void __exit ocfs2_stack_glue_exit(void)
 718 {
 719         memset(&locking_max_version, 0,
 720                sizeof(struct ocfs2_protocol_version));
 721         locking_max_version.pv_major = 0;
 722         locking_max_version.pv_minor = 0;
 723         ocfs2_sysfs_exit();
 724         if (ocfs2_table_header)
 725                 unregister_sysctl_table(ocfs2_table_header);
 726 }
 727
 728 MODULE_AUTHOR("Oracle");
 729 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
 730 MODULE_LICENSE("GPL");
 731 module_init(ocfs2_stack_glue_init);
 732 module_exit(ocfs2_stack_glue_exit);