xref: /openbmc/linux/fs/ocfs2/stackglue.c (revision 55fd7e02)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* -*- mode: c; c-basic-offset: 8; -*-
3  * vim: noexpandtab sw=8 ts=8 sts=0:
4  *
5  * stackglue.c
6  *
7  * Code which implements an OCFS2 specific interface to underlying
8  * cluster stacks.
9  *
10  * Copyright (C) 2007, 2009 Oracle.  All rights reserved.
11  */
12 
13 #include <linux/list.h>
14 #include <linux/spinlock.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/kmod.h>
18 #include <linux/fs.h>
19 #include <linux/kobject.h>
20 #include <linux/sysfs.h>
21 #include <linux/sysctl.h>
22 
23 #include "ocfs2_fs.h"
24 
25 #include "stackglue.h"
26 
27 #define OCFS2_STACK_PLUGIN_O2CB		"o2cb"
28 #define OCFS2_STACK_PLUGIN_USER		"user"
29 #define OCFS2_MAX_HB_CTL_PATH		256
30 
31 static struct ocfs2_protocol_version locking_max_version;
32 static DEFINE_SPINLOCK(ocfs2_stack_lock);
33 static LIST_HEAD(ocfs2_stack_list);
34 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
35 static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
36 
37 /*
38  * The stack currently in use.  If not null, active_stack->sp_count > 0,
39  * the module is pinned, and the locking protocol cannot be changed.
40  */
41 static struct ocfs2_stack_plugin *active_stack;
42 
43 static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
44 {
45 	struct ocfs2_stack_plugin *p;
46 
47 	assert_spin_locked(&ocfs2_stack_lock);
48 
49 	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
50 		if (!strcmp(p->sp_name, name))
51 			return p;
52 	}
53 
54 	return NULL;
55 }
56 
57 static int ocfs2_stack_driver_request(const char *stack_name,
58 				      const char *plugin_name)
59 {
60 	int rc;
61 	struct ocfs2_stack_plugin *p;
62 
63 	spin_lock(&ocfs2_stack_lock);
64 
65 	/*
66 	 * If the stack passed by the filesystem isn't the selected one,
67 	 * we can't continue.
68 	 */
69 	if (strcmp(stack_name, cluster_stack_name)) {
70 		rc = -EBUSY;
71 		goto out;
72 	}
73 
74 	if (active_stack) {
75 		/*
76 		 * If the active stack isn't the one we want, it cannot
77 		 * be selected right now.
78 		 */
79 		if (!strcmp(active_stack->sp_name, plugin_name))
80 			rc = 0;
81 		else
82 			rc = -EBUSY;
83 		goto out;
84 	}
85 
86 	p = ocfs2_stack_lookup(plugin_name);
87 	if (!p || !try_module_get(p->sp_owner)) {
88 		rc = -ENOENT;
89 		goto out;
90 	}
91 
92 	active_stack = p;
93 	rc = 0;
94 
95 out:
96 	/* If we found it, pin it */
97 	if (!rc)
98 		active_stack->sp_count++;
99 
100 	spin_unlock(&ocfs2_stack_lock);
101 	return rc;
102 }
103 
104 /*
105  * This function looks up the appropriate stack and makes it active.  If
106  * there is no stack, it tries to load it.  It will fail if the stack still
107  * cannot be found.  It will also fail if a different stack is in use.
108  */
109 static int ocfs2_stack_driver_get(const char *stack_name)
110 {
111 	int rc;
112 	char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
113 
114 	/*
115 	 * Classic stack does not pass in a stack name.  This is
116 	 * compatible with older tools as well.
117 	 */
118 	if (!stack_name || !*stack_name)
119 		stack_name = OCFS2_STACK_PLUGIN_O2CB;
120 
121 	if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
122 		printk(KERN_ERR
123 		       "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
124 		       stack_name);
125 		return -EINVAL;
126 	}
127 
128 	/* Anything that isn't the classic stack is a user stack */
129 	if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
130 		plugin_name = OCFS2_STACK_PLUGIN_USER;
131 
132 	rc = ocfs2_stack_driver_request(stack_name, plugin_name);
133 	if (rc == -ENOENT) {
134 		request_module("ocfs2_stack_%s", plugin_name);
135 		rc = ocfs2_stack_driver_request(stack_name, plugin_name);
136 	}
137 
138 	if (rc == -ENOENT) {
139 		printk(KERN_ERR
140 		       "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
141 		       plugin_name);
142 	} else if (rc == -EBUSY) {
143 		printk(KERN_ERR
144 		       "ocfs2: A different cluster stack is in use\n");
145 	}
146 
147 	return rc;
148 }
149 
150 static void ocfs2_stack_driver_put(void)
151 {
152 	spin_lock(&ocfs2_stack_lock);
153 	BUG_ON(active_stack == NULL);
154 	BUG_ON(active_stack->sp_count == 0);
155 
156 	active_stack->sp_count--;
157 	if (!active_stack->sp_count) {
158 		module_put(active_stack->sp_owner);
159 		active_stack = NULL;
160 	}
161 	spin_unlock(&ocfs2_stack_lock);
162 }
163 
164 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
165 {
166 	int rc;
167 
168 	spin_lock(&ocfs2_stack_lock);
169 	if (!ocfs2_stack_lookup(plugin->sp_name)) {
170 		plugin->sp_count = 0;
171 		plugin->sp_max_proto = locking_max_version;
172 		list_add(&plugin->sp_list, &ocfs2_stack_list);
173 		printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
174 		       plugin->sp_name);
175 		rc = 0;
176 	} else {
177 		printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
178 		       plugin->sp_name);
179 		rc = -EEXIST;
180 	}
181 	spin_unlock(&ocfs2_stack_lock);
182 
183 	return rc;
184 }
185 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
186 
187 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
188 {
189 	struct ocfs2_stack_plugin *p;
190 
191 	spin_lock(&ocfs2_stack_lock);
192 	p = ocfs2_stack_lookup(plugin->sp_name);
193 	if (p) {
194 		BUG_ON(p != plugin);
195 		BUG_ON(plugin == active_stack);
196 		BUG_ON(plugin->sp_count != 0);
197 		list_del_init(&plugin->sp_list);
198 		printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
199 		       plugin->sp_name);
200 	} else {
201 		printk(KERN_ERR "Stack \"%s\" is not registered\n",
202 		       plugin->sp_name);
203 	}
204 	spin_unlock(&ocfs2_stack_lock);
205 }
206 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
207 
208 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
209 {
210 	struct ocfs2_stack_plugin *p;
211 
212 	spin_lock(&ocfs2_stack_lock);
213 	if (memcmp(max_proto, &locking_max_version,
214 		   sizeof(struct ocfs2_protocol_version))) {
215 		BUG_ON(locking_max_version.pv_major != 0);
216 
217 		locking_max_version = *max_proto;
218 		list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
219 			p->sp_max_proto = locking_max_version;
220 		}
221 	}
222 	spin_unlock(&ocfs2_stack_lock);
223 }
224 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
225 
226 
227 /*
228  * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
229  * for the ast and bast functions.  They will pass the lksb to the ast
230  * and bast.  The caller can wrap the lksb with their own structure to
231  * get more information.
232  */
233 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
234 		   int mode,
235 		   struct ocfs2_dlm_lksb *lksb,
236 		   u32 flags,
237 		   void *name,
238 		   unsigned int namelen)
239 {
240 	if (!lksb->lksb_conn)
241 		lksb->lksb_conn = conn;
242 	else
243 		BUG_ON(lksb->lksb_conn != conn);
244 	return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
245 					      name, namelen);
246 }
247 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
248 
249 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
250 		     struct ocfs2_dlm_lksb *lksb,
251 		     u32 flags)
252 {
253 	BUG_ON(lksb->lksb_conn == NULL);
254 
255 	return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
256 }
257 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
258 
259 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
260 {
261 	return active_stack->sp_ops->lock_status(lksb);
262 }
263 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
264 
265 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
266 {
267 	return active_stack->sp_ops->lvb_valid(lksb);
268 }
269 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
270 
271 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
272 {
273 	return active_stack->sp_ops->lock_lvb(lksb);
274 }
275 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
276 
277 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
278 {
279 	active_stack->sp_ops->dump_lksb(lksb);
280 }
281 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
282 
283 int ocfs2_stack_supports_plocks(void)
284 {
285 	return active_stack && active_stack->sp_ops->plock;
286 }
287 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
288 
289 /*
290  * ocfs2_plock() can only be safely called if
291  * ocfs2_stack_supports_plocks() returned true
292  */
293 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
294 		struct file *file, int cmd, struct file_lock *fl)
295 {
296 	WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
297 	if (active_stack->sp_ops->plock)
298 		return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
299 	return -EOPNOTSUPP;
300 }
301 EXPORT_SYMBOL_GPL(ocfs2_plock);
302 
303 int ocfs2_cluster_connect(const char *stack_name,
304 			  const char *cluster_name,
305 			  int cluster_name_len,
306 			  const char *group,
307 			  int grouplen,
308 			  struct ocfs2_locking_protocol *lproto,
309 			  void (*recovery_handler)(int node_num,
310 						   void *recovery_data),
311 			  void *recovery_data,
312 			  struct ocfs2_cluster_connection **conn)
313 {
314 	int rc = 0;
315 	struct ocfs2_cluster_connection *new_conn;
316 
317 	BUG_ON(group == NULL);
318 	BUG_ON(conn == NULL);
319 	BUG_ON(recovery_handler == NULL);
320 
321 	if (grouplen > GROUP_NAME_MAX) {
322 		rc = -EINVAL;
323 		goto out;
324 	}
325 
326 	if (memcmp(&lproto->lp_max_version, &locking_max_version,
327 		   sizeof(struct ocfs2_protocol_version))) {
328 		rc = -EINVAL;
329 		goto out;
330 	}
331 
332 	new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
333 			   GFP_KERNEL);
334 	if (!new_conn) {
335 		rc = -ENOMEM;
336 		goto out;
337 	}
338 
339 	strlcpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
340 	new_conn->cc_namelen = grouplen;
341 	if (cluster_name_len)
342 		strlcpy(new_conn->cc_cluster_name, cluster_name,
343 			CLUSTER_NAME_MAX + 1);
344 	new_conn->cc_cluster_name_len = cluster_name_len;
345 	new_conn->cc_recovery_handler = recovery_handler;
346 	new_conn->cc_recovery_data = recovery_data;
347 
348 	new_conn->cc_proto = lproto;
349 	/* Start the new connection at our maximum compatibility level */
350 	new_conn->cc_version = lproto->lp_max_version;
351 
352 	/* This will pin the stack driver if successful */
353 	rc = ocfs2_stack_driver_get(stack_name);
354 	if (rc)
355 		goto out_free;
356 
357 	rc = active_stack->sp_ops->connect(new_conn);
358 	if (rc) {
359 		ocfs2_stack_driver_put();
360 		goto out_free;
361 	}
362 
363 	*conn = new_conn;
364 
365 out_free:
366 	if (rc)
367 		kfree(new_conn);
368 
369 out:
370 	return rc;
371 }
372 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
373 
374 /* The caller will ensure all nodes have the same cluster stack */
375 int ocfs2_cluster_connect_agnostic(const char *group,
376 				   int grouplen,
377 				   struct ocfs2_locking_protocol *lproto,
378 				   void (*recovery_handler)(int node_num,
379 							    void *recovery_data),
380 				   void *recovery_data,
381 				   struct ocfs2_cluster_connection **conn)
382 {
383 	char *stack_name = NULL;
384 
385 	if (cluster_stack_name[0])
386 		stack_name = cluster_stack_name;
387 	return ocfs2_cluster_connect(stack_name, NULL, 0, group, grouplen,
388 				     lproto, recovery_handler, recovery_data,
389 				     conn);
390 }
391 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
392 
393 /* If hangup_pending is 0, the stack driver will be dropped */
394 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
395 			     int hangup_pending)
396 {
397 	int ret;
398 
399 	BUG_ON(conn == NULL);
400 
401 	ret = active_stack->sp_ops->disconnect(conn);
402 
403 	/* XXX Should we free it anyway? */
404 	if (!ret) {
405 		kfree(conn);
406 		if (!hangup_pending)
407 			ocfs2_stack_driver_put();
408 	}
409 
410 	return ret;
411 }
412 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
413 
414 /*
415  * Leave the group for this filesystem.  This is executed by a userspace
416  * program (stored in ocfs2_hb_ctl_path).
417  */
418 static void ocfs2_leave_group(const char *group)
419 {
420 	int ret;
421 	char *argv[5], *envp[3];
422 
423 	argv[0] = ocfs2_hb_ctl_path;
424 	argv[1] = "-K";
425 	argv[2] = "-u";
426 	argv[3] = (char *)group;
427 	argv[4] = NULL;
428 
429 	/* minimal command environment taken from cpu_run_sbin_hotplug */
430 	envp[0] = "HOME=/";
431 	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
432 	envp[2] = NULL;
433 
434 	ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
435 	if (ret < 0) {
436 		printk(KERN_ERR
437 		       "ocfs2: Error %d running user helper "
438 		       "\"%s %s %s %s\"\n",
439 		       ret, argv[0], argv[1], argv[2], argv[3]);
440 	}
441 }
442 
443 /*
444  * Hangup is a required post-umount.  ocfs2-tools software expects the
445  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
446  * regardless of whether the DLM got started, so we can't do it
447  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
448  * the actual work.
449  */
450 void ocfs2_cluster_hangup(const char *group, int grouplen)
451 {
452 	BUG_ON(group == NULL);
453 	BUG_ON(group[grouplen] != '\0');
454 
455 	ocfs2_leave_group(group);
456 
457 	/* cluster_disconnect() was called with hangup_pending==1 */
458 	ocfs2_stack_driver_put();
459 }
460 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
461 
462 int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
463 			    unsigned int *node)
464 {
465 	return active_stack->sp_ops->this_node(conn, 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_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_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_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_IRUGO | S_IWUSR,
595 	       ocfs2_cluster_stack_show,
596 	       ocfs2_cluster_stack_store);
597 
598 
599 
600 static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
601 					struct kobj_attribute *attr,
602 					char *buf)
603 {
604 	return snprintf(buf, PAGE_SIZE, "1\n");
605 }
606 
607 static struct kobj_attribute ocfs2_attr_dlm_recover_support =
608 	__ATTR(dlm_recover_callback_support, S_IRUGO,
609 	       ocfs2_dlm_recover_show, NULL);
610 
611 static struct attribute *ocfs2_attrs[] = {
612 	&ocfs2_attr_max_locking_protocol.attr,
613 	&ocfs2_attr_loaded_cluster_plugins.attr,
614 	&ocfs2_attr_active_cluster_plugin.attr,
615 	&ocfs2_attr_cluster_stack.attr,
616 	&ocfs2_attr_dlm_recover_support.attr,
617 	NULL,
618 };
619 
620 static const struct attribute_group ocfs2_attr_group = {
621 	.attrs = ocfs2_attrs,
622 };
623 
624 struct kset *ocfs2_kset;
625 EXPORT_SYMBOL_GPL(ocfs2_kset);
626 
627 static void ocfs2_sysfs_exit(void)
628 {
629 	kset_unregister(ocfs2_kset);
630 }
631 
632 static int ocfs2_sysfs_init(void)
633 {
634 	int ret;
635 
636 	ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
637 	if (!ocfs2_kset)
638 		return -ENOMEM;
639 
640 	ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
641 	if (ret)
642 		goto error;
643 
644 	return 0;
645 
646 error:
647 	kset_unregister(ocfs2_kset);
648 	return ret;
649 }
650 
651 /*
652  * Sysctl bits
653  *
654  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
655  * make as much sense in a multiple cluster stack world, but it's safer
656  * and easier to preserve the name.
657  */
658 
659 static struct ctl_table ocfs2_nm_table[] = {
660 	{
661 		.procname	= "hb_ctl_path",
662 		.data		= ocfs2_hb_ctl_path,
663 		.maxlen		= OCFS2_MAX_HB_CTL_PATH,
664 		.mode		= 0644,
665 		.proc_handler	= proc_dostring,
666 	},
667 	{ }
668 };
669 
670 static struct ctl_table ocfs2_mod_table[] = {
671 	{
672 		.procname	= "nm",
673 		.data		= NULL,
674 		.maxlen		= 0,
675 		.mode		= 0555,
676 		.child		= ocfs2_nm_table
677 	},
678 	{ }
679 };
680 
681 static struct ctl_table ocfs2_kern_table[] = {
682 	{
683 		.procname	= "ocfs2",
684 		.data		= NULL,
685 		.maxlen		= 0,
686 		.mode		= 0555,
687 		.child		= ocfs2_mod_table
688 	},
689 	{ }
690 };
691 
692 static struct ctl_table ocfs2_root_table[] = {
693 	{
694 		.procname	= "fs",
695 		.data		= NULL,
696 		.maxlen		= 0,
697 		.mode		= 0555,
698 		.child		= ocfs2_kern_table
699 	},
700 	{ }
701 };
702 
703 static struct ctl_table_header *ocfs2_table_header;
704 
705 
706 /*
707  * Initialization
708  */
709 
710 static int __init ocfs2_stack_glue_init(void)
711 {
712 	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
713 
714 	ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
715 	if (!ocfs2_table_header) {
716 		printk(KERN_ERR
717 		       "ocfs2 stack glue: unable to register sysctl\n");
718 		return -ENOMEM; /* or something. */
719 	}
720 
721 	return ocfs2_sysfs_init();
722 }
723 
724 static void __exit ocfs2_stack_glue_exit(void)
725 {
726 	memset(&locking_max_version, 0,
727 	       sizeof(struct ocfs2_protocol_version));
728 	ocfs2_sysfs_exit();
729 	if (ocfs2_table_header)
730 		unregister_sysctl_table(ocfs2_table_header);
731 }
732 
733 MODULE_AUTHOR("Oracle");
734 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
735 MODULE_LICENSE("GPL");
736 module_init(ocfs2_stack_glue_init);
737 module_exit(ocfs2_stack_glue_exit);
738