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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/stackglue.c

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  1 /* -*- mode: c; c-basic-offset: 8; -*-
  2  * vim: noexpandtab sw=8 ts=8 sts=0:
  3  *
  4  * stackglue.c
  5  *
  6  * Code which implements an OCFS2 specific interface to underlying
  7  * cluster stacks.
  8  *
  9  * Copyright (C) 2007, 2009 Oracle.  All rights reserved.
 10  *
 11  * This program is free software; you can redistribute it and/or
 12  * modify it under the terms of the GNU General Public
 13  * License as published by the Free Software Foundation, version 2.
 14  *
 15  * This program is distributed in the hope that it will be useful,
 16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 18  * General Public License for more details.
 19  */
 20 
 21 #include <linux/list.h>
 22 #include <linux/spinlock.h>
 23 #include <linux/module.h>
 24 #include <linux/slab.h>
 25 #include <linux/kmod.h>
 26 #include <linux/fs.h>
 27 #include <linux/kobject.h>
 28 #include <linux/sysfs.h>
 29 #include <linux/sysctl.h>
 30 
 31 #include "ocfs2_fs.h"
 32 
 33 #include "stackglue.h"
 34 
 35 #define OCFS2_STACK_PLUGIN_O2CB         "o2cb"
 36 #define OCFS2_STACK_PLUGIN_USER         "user"
 37 #define OCFS2_MAX_HB_CTL_PATH           256
 38 
 39 static struct ocfs2_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 *cluster_name,
313                           int cluster_name_len,
314                           const char *group,
315                           int grouplen,
316                           struct ocfs2_locking_protocol *lproto,
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         if (memcmp(&lproto->lp_max_version, &locking_max_version,
335                    sizeof(struct ocfs2_protocol_version))) {
336                 rc = -EINVAL;
337                 goto out;
338         }
339 
340         new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
341                            GFP_KERNEL);
342         if (!new_conn) {
343                 rc = -ENOMEM;
344                 goto out;
345         }
346 
347         strlcpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
348         new_conn->cc_namelen = grouplen;
349         if (cluster_name_len)
350                 strlcpy(new_conn->cc_cluster_name, cluster_name,
351                         CLUSTER_NAME_MAX + 1);
352         new_conn->cc_cluster_name_len = cluster_name_len;
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, NULL, 0, group, grouplen,
396                                      lproto, recovery_handler, recovery_data,
397                                      conn);
398 }
399 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
400 
401 /* If hangup_pending is 0, the stack driver will be dropped */
402 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
403                              int hangup_pending)
404 {
405         int ret;
406 
407         BUG_ON(conn == NULL);
408 
409         ret = active_stack->sp_ops->disconnect(conn);
410 
411         /* XXX Should we free it anyway? */
412         if (!ret) {
413                 kfree(conn);
414                 if (!hangup_pending)
415                         ocfs2_stack_driver_put();
416         }
417 
418         return ret;
419 }
420 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
421 
422 /*
423  * Leave the group for this filesystem.  This is executed by a userspace
424  * program (stored in ocfs2_hb_ctl_path).
425  */
426 static void ocfs2_leave_group(const char *group)
427 {
428         int ret;
429         char *argv[5], *envp[3];
430 
431         argv[0] = ocfs2_hb_ctl_path;
432         argv[1] = "-K";
433         argv[2] = "-u";
434         argv[3] = (char *)group;
435         argv[4] = NULL;
436 
437         /* minimal command environment taken from cpu_run_sbin_hotplug */
438         envp[0] = "HOME=/";
439         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
440         envp[2] = NULL;
441 
442         ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
443         if (ret < 0) {
444                 printk(KERN_ERR
445                        "ocfs2: Error %d running user helper "
446                        "\"%s %s %s %s\"\n",
447                        ret, argv[0], argv[1], argv[2], argv[3]);
448         }
449 }
450 
451 /*
452  * Hangup is a required post-umount.  ocfs2-tools software expects the
453  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
454  * regardless of whether the DLM got started, so we can't do it
455  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
456  * the actual work.
457  */
458 void ocfs2_cluster_hangup(const char *group, int grouplen)
459 {
460         BUG_ON(group == NULL);
461         BUG_ON(group[grouplen] != '\0');
462 
463         ocfs2_leave_group(group);
464 
465         /* cluster_disconnect() was called with hangup_pending==1 */
466         ocfs2_stack_driver_put();
467 }
468 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
469 
470 int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
471                             unsigned int *node)
472 {
473         return active_stack->sp_ops->this_node(conn, node);
474 }
475 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
476 
477 
478 /*
479  * Sysfs bits
480  */
481 
482 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
483                                                struct kobj_attribute *attr,
484                                                char *buf)
485 {
486         ssize_t ret = 0;
487 
488         spin_lock(&ocfs2_stack_lock);
489         if (locking_max_version.pv_major)
490                 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
491                                locking_max_version.pv_major,
492                                locking_max_version.pv_minor);
493         spin_unlock(&ocfs2_stack_lock);
494 
495         return ret;
496 }
497 
498 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
499         __ATTR(max_locking_protocol, S_IRUGO,
500                ocfs2_max_locking_protocol_show, NULL);
501 
502 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
503                                                  struct kobj_attribute *attr,
504                                                  char *buf)
505 {
506         ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
507         struct ocfs2_stack_plugin *p;
508 
509         spin_lock(&ocfs2_stack_lock);
510         list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
511                 ret = snprintf(buf, remain, "%s\n",
512                                p->sp_name);
513                 if (ret < 0) {
514                         total = ret;
515                         break;
516                 }
517                 if (ret == remain) {
518                         /* snprintf() didn't fit */
519                         total = -E2BIG;
520                         break;
521                 }
522                 total += ret;
523                 remain -= ret;
524         }
525         spin_unlock(&ocfs2_stack_lock);
526 
527         return total;
528 }
529 
530 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
531         __ATTR(loaded_cluster_plugins, S_IRUGO,
532                ocfs2_loaded_cluster_plugins_show, NULL);
533 
534 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
535                                                 struct kobj_attribute *attr,
536                                                 char *buf)
537 {
538         ssize_t ret = 0;
539 
540         spin_lock(&ocfs2_stack_lock);
541         if (active_stack) {
542                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
543                                active_stack->sp_name);
544                 if (ret == PAGE_SIZE)
545                         ret = -E2BIG;
546         }
547         spin_unlock(&ocfs2_stack_lock);
548 
549         return ret;
550 }
551 
552 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
553         __ATTR(active_cluster_plugin, S_IRUGO,
554                ocfs2_active_cluster_plugin_show, NULL);
555 
556 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
557                                         struct kobj_attribute *attr,
558                                         char *buf)
559 {
560         ssize_t ret;
561         spin_lock(&ocfs2_stack_lock);
562         ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
563         spin_unlock(&ocfs2_stack_lock);
564 
565         return ret;
566 }
567 
568 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
569                                          struct kobj_attribute *attr,
570                                          const char *buf, size_t count)
571 {
572         size_t len = count;
573         ssize_t ret;
574 
575         if (len == 0)
576                 return len;
577 
578         if (buf[len - 1] == '\n')
579                 len--;
580 
581         if ((len != OCFS2_STACK_LABEL_LEN) ||
582             (strnlen(buf, len) != len))
583                 return -EINVAL;
584 
585         spin_lock(&ocfs2_stack_lock);
586         if (active_stack) {
587                 if (!strncmp(buf, cluster_stack_name, len))
588                         ret = count;
589                 else
590                         ret = -EBUSY;
591         } else {
592                 memcpy(cluster_stack_name, buf, len);
593                 ret = count;
594         }
595         spin_unlock(&ocfs2_stack_lock);
596 
597         return ret;
598 }
599 
600 
601 static struct kobj_attribute ocfs2_attr_cluster_stack =
602         __ATTR(cluster_stack, S_IRUGO | S_IWUSR,
603                ocfs2_cluster_stack_show,
604                ocfs2_cluster_stack_store);
605 
606 
607 
608 static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
609                                         struct kobj_attribute *attr,
610                                         char *buf)
611 {
612         return snprintf(buf, PAGE_SIZE, "1\n");
613 }
614 
615 static struct kobj_attribute ocfs2_attr_dlm_recover_support =
616         __ATTR(dlm_recover_callback_support, S_IRUGO,
617                ocfs2_dlm_recover_show, NULL);
618 
619 static struct attribute *ocfs2_attrs[] = {
620         &ocfs2_attr_max_locking_protocol.attr,
621         &ocfs2_attr_loaded_cluster_plugins.attr,
622         &ocfs2_attr_active_cluster_plugin.attr,
623         &ocfs2_attr_cluster_stack.attr,
624         &ocfs2_attr_dlm_recover_support.attr,
625         NULL,
626 };
627 
628 static const struct attribute_group ocfs2_attr_group = {
629         .attrs = ocfs2_attrs,
630 };
631 
632 struct kset *ocfs2_kset;
633 EXPORT_SYMBOL_GPL(ocfs2_kset);
634 
635 static void ocfs2_sysfs_exit(void)
636 {
637         kset_unregister(ocfs2_kset);
638 }
639 
640 static int ocfs2_sysfs_init(void)
641 {
642         int ret;
643 
644         ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
645         if (!ocfs2_kset)
646                 return -ENOMEM;
647 
648         ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
649         if (ret)
650                 goto error;
651 
652         return 0;
653 
654 error:
655         kset_unregister(ocfs2_kset);
656         return ret;
657 }
658 
659 /*
660  * Sysctl bits
661  *
662  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
663  * make as much sense in a multiple cluster stack world, but it's safer
664  * and easier to preserve the name.
665  */
666 
667 #define FS_OCFS2_NM             1
668 
669 static struct ctl_table ocfs2_nm_table[] = {
670         {
671                 .procname       = "hb_ctl_path",
672                 .data           = ocfs2_hb_ctl_path,
673                 .maxlen         = OCFS2_MAX_HB_CTL_PATH,
674                 .mode           = 0644,
675                 .proc_handler   = proc_dostring,
676         },
677         { }
678 };
679 
680 static struct ctl_table ocfs2_mod_table[] = {
681         {
682                 .procname       = "nm",
683                 .data           = NULL,
684                 .maxlen         = 0,
685                 .mode           = 0555,
686                 .child          = ocfs2_nm_table
687         },
688         { }
689 };
690 
691 static struct ctl_table ocfs2_kern_table[] = {
692         {
693                 .procname       = "ocfs2",
694                 .data           = NULL,
695                 .maxlen         = 0,
696                 .mode           = 0555,
697                 .child          = ocfs2_mod_table
698         },
699         { }
700 };
701 
702 static struct ctl_table ocfs2_root_table[] = {
703         {
704                 .procname       = "fs",
705                 .data           = NULL,
706                 .maxlen         = 0,
707                 .mode           = 0555,
708                 .child          = ocfs2_kern_table
709         },
710         { }
711 };
712 
713 static struct ctl_table_header *ocfs2_table_header;
714 
715 
716 /*
717  * Initialization
718  */
719 
720 static int __init ocfs2_stack_glue_init(void)
721 {
722         strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
723 
724         ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
725         if (!ocfs2_table_header) {
726                 printk(KERN_ERR
727                        "ocfs2 stack glue: unable to register sysctl\n");
728                 return -ENOMEM; /* or something. */
729         }
730 
731         return ocfs2_sysfs_init();
732 }
733 
734 static void __exit ocfs2_stack_glue_exit(void)
735 {
736         memset(&locking_max_version, 0,
737                sizeof(struct ocfs2_protocol_version));
738         ocfs2_sysfs_exit();
739         if (ocfs2_table_header)
740                 unregister_sysctl_table(ocfs2_table_header);
741 }
742 
743 MODULE_AUTHOR("Oracle");
744 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
745 MODULE_LICENSE("GPL");
746 module_init(ocfs2_stack_glue_init);
747 module_exit(ocfs2_stack_glue_exit);
748 

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