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 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 = locking_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_max_proto_version(struct ocfs2_protocol_version *max_proto)
 217 {
 218         struct ocfs2_stack_plugin *p;
 219
 220         spin_lock(&ocfs2_stack_lock);
 221         if (memcmp(max_proto, &locking_max_version,
 222                    sizeof(struct ocfs2_protocol_version))) {
 223                 BUG_ON(locking_max_version.pv_major != 0);
 224
 225                 locking_max_version = *max_proto;
 226                 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 227                         p->sp_max_proto = locking_max_version;
 228                 }
 229         }
 230         spin_unlock(&ocfs2_stack_lock);
 231 }
 232 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
 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         if (!lksb->lksb_conn)
 249                 lksb->lksb_conn = conn;
 250         else
 251                 BUG_ON(lksb->lksb_conn != conn);
 252         return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
 253                                               name, namelen);
 254 }
 255 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
 256
 257 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
 258                      struct ocfs2_dlm_lksb *lksb,
 259                      u32 flags)
 260 {
 261         BUG_ON(lksb->lksb_conn == NULL);
 262
 263         return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
 264 }
 265 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
 266
 267 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
 268 {
 269         return active_stack->sp_ops->lock_status(lksb);
 270 }
 271 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
 272
 273 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
 274 {
 275         return active_stack->sp_ops->lvb_valid(lksb);
 276 }
 277 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
 278
 279 void *ocfs2_dlm_lvb(struct 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(struct 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                           struct ocfs2_locking_protocol *lproto,
 315                           void (*recovery_handler)(int node_num,
 316                                                    void *recovery_data),
 317                           void *recovery_data,
 318                           struct ocfs2_cluster_connection **conn)
 319 {
 320         int rc = 0;
 321         struct ocfs2_cluster_connection *new_conn;
 322
 323         BUG_ON(group == NULL);
 324         BUG_ON(conn == NULL);
 325         BUG_ON(recovery_handler == NULL);
 326
 327         if (grouplen > GROUP_NAME_MAX) {
 328                 rc = -EINVAL;
 329                 goto out;
 330         }
 331
 332         if (memcmp(&lproto->lp_max_version, &locking_max_version,
 333                    sizeof(struct ocfs2_protocol_version))) {
 334                 rc = -EINVAL;
 335                 goto out;
 336         }
 337
 338         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
 339                            GFP_KERNEL);
 340         if (!new_conn) {
 341                 rc = -ENOMEM;
 342                 goto out;
 343         }
 344
 345         memcpy(new_conn->cc_name, group, grouplen);
 346         new_conn->cc_namelen = grouplen;
 347         new_conn->cc_recovery_handler = recovery_handler;
 348         new_conn->cc_recovery_data = recovery_data;
 349
 350         new_conn->cc_proto = lproto;
 351         /* Start the new connection at our maximum compatibility level */
 352         new_conn->cc_version = lproto->lp_max_version;
 353
 354         /* This will pin the stack driver if successful */
 355         rc = ocfs2_stack_driver_get(stack_name);
 356         if (rc)
 357                 goto out_free;
 358
 359         rc = active_stack->sp_ops->connect(new_conn);
 360         if (rc) {
 361                 ocfs2_stack_driver_put();
 362                 goto out_free;
 363         }
 364
 365         *conn = new_conn;
 366
 367 out_free:
 368         if (rc)
 369                 kfree(new_conn);
 370
 371 out:
 372         return rc;
 373 }
 374 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
 375
 376 /* The caller will ensure all nodes have the same cluster stack */
 377 int ocfs2_cluster_connect_agnostic(const char *group,
 378                                    int grouplen,
 379                                    struct ocfs2_locking_protocol *lproto,
 380                                    void (*recovery_handler)(int node_num,
 381                                                             void *recovery_data),
 382                                    void *recovery_data,
 383                                    struct ocfs2_cluster_connection **conn)
 384 {
 385         char *stack_name = NULL;
 386
 387         if (cluster_stack_name[0])
 388                 stack_name = cluster_stack_name;
 389         return ocfs2_cluster_connect(stack_name, group, grouplen, lproto,
 390                                      recovery_handler, recovery_data, conn);
 391 }
 392 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
 393
 394 /* If hangup_pending is 0, the stack driver will be dropped */
 395 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
 396                              int hangup_pending)
 397 {
 398         int ret;
 399
 400         BUG_ON(conn == NULL);
 401
 402         ret = active_stack->sp_ops->disconnect(conn);
 403
 404         /* XXX Should we free it anyway? */
 405         if (!ret) {
 406                 kfree(conn);
 407                 if (!hangup_pending)
 408                         ocfs2_stack_driver_put();
 409         }
 410
 411         return ret;
 412 }
 413 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
 414
 415 /*
 416  * Leave the group for this filesystem.  This is executed by a userspace
 417  * program (stored in ocfs2_hb_ctl_path).
 418  */
 419 static void ocfs2_leave_group(const char *group)
 420 {
 421         int ret;
 422         char *argv[5], *envp[3];
 423
 424         argv[0] = ocfs2_hb_ctl_path;
 425         argv[1] = "-K";
 426         argv[2] = "-u";
 427         argv[3] = (char *)group;
 428         argv[4] = NULL;
 429
 430         /* minimal command environment taken from cpu_run_sbin_hotplug */
 431         envp[0] = "HOME=/";
 432         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
 433         envp[2] = NULL;
 434
 435         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
 436         if (ret < 0) {
 437                 printk(KERN_ERR
 438                        "ocfs2: Error %d running user helper "
 439                        "\"%s %s %s %s\"\n",
 440                        ret, argv[0], argv[1], argv[2], argv[3]);
 441         }
 442 }
 443
 444 /*
 445  * Hangup is a required post-umount.  ocfs2-tools software expects the
 446  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
 447  * regardless of whether the DLM got started, so we can't do it
 448  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
 449  * the actual work.
 450  */
 451 void ocfs2_cluster_hangup(const char *group, int grouplen)
 452 {
 453         BUG_ON(group == NULL);
 454         BUG_ON(group[grouplen] != '\0');
 455
 456         ocfs2_leave_group(group);
 457
 458         /* cluster_disconnect() was called with hangup_pending==1 */
 459         ocfs2_stack_driver_put();
 460 }
 461 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
 462
 463 int ocfs2_cluster_this_node(unsigned int *node)
 464 {
 465         return active_stack->sp_ops->this_node(node);
 466 }
 467 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
 468
 469
 470 /*
 471  * Sysfs bits
 472  */
 473
 474 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
 475                                                struct kobj_attribute *attr,
 476                                                char *buf)
 477 {
 478         ssize_t ret = 0;
 479
 480         spin_lock(&ocfs2_stack_lock);
 481         if (locking_max_version.pv_major)
 482                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
 483                                locking_max_version.pv_major,
 484                                locking_max_version.pv_minor);
 485         spin_unlock(&ocfs2_stack_lock);
 486
 487         return ret;
 488 }
 489
 490 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
 491         __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
 492                ocfs2_max_locking_protocol_show, NULL);
 493
 494 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
 495                                                  struct kobj_attribute *attr,
 496                                                  char *buf)
 497 {
 498         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
 499         struct ocfs2_stack_plugin *p;
 500
 501         spin_lock(&ocfs2_stack_lock);
 502         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
 503                 ret = snprintf(buf, remain, "%s\n",
 504                                p->sp_name);
 505                 if (ret < 0) {
 506                         total = ret;
 507                         break;
 508                 }
 509                 if (ret == remain) {
 510                         /* snprintf() didn't fit */
 511                         total = -E2BIG;
 512                         break;
 513                 }
 514                 total += ret;
 515                 remain -= ret;
 516         }
 517         spin_unlock(&ocfs2_stack_lock);
 518
 519         return total;
 520 }
 521
 522 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
 523         __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
 524                ocfs2_loaded_cluster_plugins_show, NULL);
 525
 526 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
 527                                                 struct kobj_attribute *attr,
 528                                                 char *buf)
 529 {
 530         ssize_t ret = 0;
 531
 532         spin_lock(&ocfs2_stack_lock);
 533         if (active_stack) {
 534                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 535                                active_stack->sp_name);
 536                 if (ret == PAGE_SIZE)
 537                         ret = -E2BIG;
 538         }
 539         spin_unlock(&ocfs2_stack_lock);
 540
 541         return ret;
 542 }
 543
 544 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
 545         __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
 546                ocfs2_active_cluster_plugin_show, NULL);
 547
 548 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
 549                                         struct kobj_attribute *attr,
 550                                         char *buf)
 551 {
 552         ssize_t ret;
 553         spin_lock(&ocfs2_stack_lock);
 554         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
 555         spin_unlock(&ocfs2_stack_lock);
 556
 557         return ret;
 558 }
 559
 560 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
 561                                          struct kobj_attribute *attr,
 562                                          const char *buf, size_t count)
 563 {
 564         size_t len = count;
 565         ssize_t ret;
 566
 567         if (len == 0)
 568                 return len;
 569
 570         if (buf[len - 1] == '\n')
 571                 len--;
 572
 573         if ((len != OCFS2_STACK_LABEL_LEN) ||
 574             (strnlen(buf, len) != len))
 575                 return -EINVAL;
 576
 577         spin_lock(&ocfs2_stack_lock);
 578         if (active_stack) {
 579                 if (!strncmp(buf, cluster_stack_name, len))
 580                         ret = count;
 581                 else
 582                         ret = -EBUSY;
 583         } else {
 584                 memcpy(cluster_stack_name, buf, len);
 585                 ret = count;
 586         }
 587         spin_unlock(&ocfs2_stack_lock);
 588
 589         return ret;
 590 }
 591
 592
 593 static struct kobj_attribute ocfs2_attr_cluster_stack =
 594         __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
 595                ocfs2_cluster_stack_show,
 596                ocfs2_cluster_stack_store);
 597
 598 static struct attribute *ocfs2_attrs[] = {
 599         &ocfs2_attr_max_locking_protocol.attr,
 600         &ocfs2_attr_loaded_cluster_plugins.attr,
 601         &ocfs2_attr_active_cluster_plugin.attr,
 602         &ocfs2_attr_cluster_stack.attr,
 603         NULL,
 604 };
 605
 606 static struct attribute_group ocfs2_attr_group = {
 607         .attrs = ocfs2_attrs,
 608 };
 609
 610 static struct kset *ocfs2_kset;
 611
 612 static void ocfs2_sysfs_exit(void)
 613 {
 614         kset_unregister(ocfs2_kset);
 615 }
 616
 617 static int ocfs2_sysfs_init(void)
 618 {
 619         int ret;
 620
 621         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
 622         if (!ocfs2_kset)
 623                 return -ENOMEM;
 624
 625         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
 626         if (ret)
 627                 goto error;
 628
 629         return 0;
 630
 631 error:
 632         kset_unregister(ocfs2_kset);
 633         return ret;
 634 }
 635
 636 /*
 637  * Sysctl bits
 638  *
 639  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
 640  * make as much sense in a multiple cluster stack world, but it's safer
 641  * and easier to preserve the name.
 642  */
 643
 644 #define FS_OCFS2_NM             1
 645
 646 static ctl_table ocfs2_nm_table[] = {
 647         {
 648                 .procname       = "hb_ctl_path",
 649                 .data           = ocfs2_hb_ctl_path,
 650                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
 651                 .mode           = 0644,
 652                 .proc_handler   = proc_dostring,
 653         },
 654         { }
 655 };
 656
 657 static ctl_table ocfs2_mod_table[] = {
 658         {
 659                 .procname       = "nm",
 660                 .data           = NULL,
 661                 .maxlen         = 0,
 662                 .mode           = 0555,
 663                 .child          = ocfs2_nm_table
 664         },
 665         { }
 666 };
 667
 668 static ctl_table ocfs2_kern_table[] = {
 669         {
 670                 .procname       = "ocfs2",
 671                 .data           = NULL,
 672                 .maxlen         = 0,
 673                 .mode           = 0555,
 674                 .child          = ocfs2_mod_table
 675         },
 676         { }
 677 };
 678
 679 static ctl_table ocfs2_root_table[] = {
 680         {
 681                 .procname       = "fs",
 682                 .data           = NULL,
 683                 .maxlen         = 0,
 684                 .mode           = 0555,
 685                 .child          = ocfs2_kern_table
 686         },
 687         { }
 688 };
 689
 690 static struct ctl_table_header *ocfs2_table_header = NULL;
 691
 692
 693 /*
 694  * Initialization
 695  */
 696
 697 static int __init ocfs2_stack_glue_init(void)
 698 {
 699         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
 700
 701         ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
 702         if (!ocfs2_table_header) {
 703                 printk(KERN_ERR
 704                        "ocfs2 stack glue: unable to register sysctl\n");
 705                 return -ENOMEM; /* or something. */
 706         }
 707
 708         return ocfs2_sysfs_init();
 709 }
 710
 711 static void __exit ocfs2_stack_glue_exit(void)
 712 {
 713         memset(&locking_max_version, 0,
 714                sizeof(struct ocfs2_protocol_version));
 715         locking_max_version.pv_major = 0;
 716         locking_max_version.pv_minor = 0;
 717         ocfs2_sysfs_exit();
 718         if (ocfs2_table_header)
 719                 unregister_sysctl_table(ocfs2_table_header);
 720 }
 721
 722 MODULE_AUTHOR("Oracle");
 723 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
 724 MODULE_LICENSE("GPL");
 725 module_init(ocfs2_stack_glue_init);
 726 module_exit(ocfs2_stack_glue_exit);