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
39static struct ocfs2_protocol_version locking_max_version;
40static DEFINE_SPINLOCK(ocfs2_stack_lock);
41static LIST_HEAD(ocfs2_stack_list);
42static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
43static 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 */
49static struct ocfs2_stack_plugin *active_stack;
50
51static 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
65static 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
103out:
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 */
117static 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
158static 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
172int 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}
193EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
194
195void 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}
214EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
215
216void 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}
232EXPORT_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 */
241int 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}
255EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
256
257int 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}
265EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
266
267int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
268{
269	return active_stack->sp_ops->lock_status(lksb);
270}
271EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
272
273int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
274{
275	return active_stack->sp_ops->lvb_valid(lksb);
276}
277EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
278
279void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
280{
281	return active_stack->sp_ops->lock_lvb(lksb);
282}
283EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
284
285void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
286{
287	active_stack->sp_ops->dump_lksb(lksb);
288}
289EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
290
291int ocfs2_stack_supports_plocks(void)
292{
293	return active_stack && active_stack->sp_ops->plock;
294}
295EXPORT_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 */
301int 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}
309EXPORT_SYMBOL_GPL(ocfs2_plock);
310
311int 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
373out_free:
374	if (rc)
375		kfree(new_conn);
376
377out:
378	return rc;
379}
380EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
381
382/* The caller will ensure all nodes have the same cluster stack */
383int 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}
399EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
400
401/* If hangup_pending is 0, the stack driver will be dropped */
402int 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}
420EXPORT_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 */
426static 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 */
458void 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}
468EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
469
470int 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}
475EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
476
477
478/*
479 * Sysfs bits
480 */
481
482static 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
498static struct kobj_attribute ocfs2_attr_max_locking_protocol =
499	__ATTR(max_locking_protocol, S_IRUGO,
500	       ocfs2_max_locking_protocol_show, NULL);
501
502static 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
530static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
531	__ATTR(loaded_cluster_plugins, S_IRUGO,
532	       ocfs2_loaded_cluster_plugins_show, NULL);
533
534static 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
552static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
553	__ATTR(active_cluster_plugin, S_IRUGO,
554	       ocfs2_active_cluster_plugin_show, NULL);
555
556static 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
568static 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
601static 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
608static 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
615static struct kobj_attribute ocfs2_attr_dlm_recover_support =
616	__ATTR(dlm_recover_callback_support, S_IRUGO,
617	       ocfs2_dlm_recover_show, NULL);
618
619static 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
628static struct attribute_group ocfs2_attr_group = {
629	.attrs = ocfs2_attrs,
630};
631
632static struct kset *ocfs2_kset;
633
634static void ocfs2_sysfs_exit(void)
635{
636	kset_unregister(ocfs2_kset);
637}
638
639static int ocfs2_sysfs_init(void)
640{
641	int ret;
642
643	ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
644	if (!ocfs2_kset)
645		return -ENOMEM;
646
647	ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
648	if (ret)
649		goto error;
650
651	return 0;
652
653error:
654	kset_unregister(ocfs2_kset);
655	return ret;
656}
657
658/*
659 * Sysctl bits
660 *
661 * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
662 * make as much sense in a multiple cluster stack world, but it's safer
663 * and easier to preserve the name.
664 */
665
666#define FS_OCFS2_NM		1
667
668static struct ctl_table ocfs2_nm_table[] = {
669	{
670		.procname	= "hb_ctl_path",
671		.data		= ocfs2_hb_ctl_path,
672		.maxlen		= OCFS2_MAX_HB_CTL_PATH,
673		.mode		= 0644,
674		.proc_handler	= proc_dostring,
675	},
676	{ }
677};
678
679static struct ctl_table ocfs2_mod_table[] = {
680	{
681		.procname	= "nm",
682		.data		= NULL,
683		.maxlen		= 0,
684		.mode		= 0555,
685		.child		= ocfs2_nm_table
686	},
687	{ }
688};
689
690static struct ctl_table ocfs2_kern_table[] = {
691	{
692		.procname	= "ocfs2",
693		.data		= NULL,
694		.maxlen		= 0,
695		.mode		= 0555,
696		.child		= ocfs2_mod_table
697	},
698	{ }
699};
700
701static struct ctl_table ocfs2_root_table[] = {
702	{
703		.procname	= "fs",
704		.data		= NULL,
705		.maxlen		= 0,
706		.mode		= 0555,
707		.child		= ocfs2_kern_table
708	},
709	{ }
710};
711
712static struct ctl_table_header *ocfs2_table_header;
713
714
715/*
716 * Initialization
717 */
718
719static int __init ocfs2_stack_glue_init(void)
720{
721	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
722
723	ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
724	if (!ocfs2_table_header) {
725		printk(KERN_ERR
726		       "ocfs2 stack glue: unable to register sysctl\n");
727		return -ENOMEM; /* or something. */
728	}
729
730	return ocfs2_sysfs_init();
731}
732
733static void __exit ocfs2_stack_glue_exit(void)
734{
735	memset(&locking_max_version, 0,
736	       sizeof(struct ocfs2_protocol_version));
737	locking_max_version.pv_major = 0;
738	locking_max_version.pv_minor = 0;
739	ocfs2_sysfs_exit();
740	if (ocfs2_table_header)
741		unregister_sysctl_table(ocfs2_table_header);
742}
743
744MODULE_AUTHOR("Oracle");
745MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
746MODULE_LICENSE("GPL");
747module_init(ocfs2_stack_glue_init);
748module_exit(ocfs2_stack_glue_exit);
749