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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
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 *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
367out_free:
368 if (rc)
369 kfree(new_conn);
370
371out:
372 return rc;
373}
374EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
375
376/* The caller will ensure all nodes have the same cluster stack */
377int 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}
392EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
393
394/* If hangup_pending is 0, the stack driver will be dropped */
395int 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}
413EXPORT_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 */
419static 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 */
451void 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}
461EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
462
463int ocfs2_cluster_this_node(unsigned int *node)
464{
465 return active_stack->sp_ops->this_node(node);
466}
467EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
468
469
470/*
471 * Sysfs bits
472 */
473
474static 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
490static 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
494static 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
522static 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
526static 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
544static 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
548static 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
560static 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
593static 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
598static 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
606static struct attribute_group ocfs2_attr_group = {
607 .attrs = ocfs2_attrs,
608};
609
610static struct kset *ocfs2_kset;
611
612static void ocfs2_sysfs_exit(void)
613{
614 kset_unregister(ocfs2_kset);
615}
616
617static 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
631error:
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
646static 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
657static 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
668static 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
679static 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
690static struct ctl_table_header *ocfs2_table_header = NULL;
691
692
693/*
694 * Initialization
695 */
696
697static 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
711static 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
722MODULE_AUTHOR("Oracle");
723MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
724MODULE_LICENSE("GPL");
725module_init(ocfs2_stack_glue_init);
726module_exit(ocfs2_stack_glue_exit);
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
51inline int ocfs2_is_o2cb_active(void)
52{
53 return !strcmp(active_stack->sp_name, OCFS2_STACK_PLUGIN_O2CB);
54}
55EXPORT_SYMBOL_GPL(ocfs2_is_o2cb_active);
56
57static 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
71static 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
109out:
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 */
123static 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
164static 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
178int 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}
199EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
200
201void 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}
220EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
221
222void 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}
238EXPORT_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 */
247int 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}
261EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
262
263int 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}
271EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
272
273int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
274{
275 return active_stack->sp_ops->lock_status(lksb);
276}
277EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
278
279int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
280{
281 return active_stack->sp_ops->lvb_valid(lksb);
282}
283EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
284
285void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
286{
287 return active_stack->sp_ops->lock_lvb(lksb);
288}
289EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
290
291void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
292{
293 active_stack->sp_ops->dump_lksb(lksb);
294}
295EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
296
297int ocfs2_stack_supports_plocks(void)
298{
299 return active_stack && active_stack->sp_ops->plock;
300}
301EXPORT_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 */
307int 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}
315EXPORT_SYMBOL_GPL(ocfs2_plock);
316
317int ocfs2_cluster_connect(const char *stack_name,
318 const char *cluster_name,
319 int cluster_name_len,
320 const char *group,
321 int grouplen,
322 struct ocfs2_locking_protocol *lproto,
323 void (*recovery_handler)(int node_num,
324 void *recovery_data),
325 void *recovery_data,
326 struct ocfs2_cluster_connection **conn)
327{
328 int rc = 0;
329 struct ocfs2_cluster_connection *new_conn;
330
331 BUG_ON(group == NULL);
332 BUG_ON(conn == NULL);
333 BUG_ON(recovery_handler == NULL);
334
335 if (grouplen > GROUP_NAME_MAX) {
336 rc = -EINVAL;
337 goto out;
338 }
339
340 if (memcmp(&lproto->lp_max_version, &locking_max_version,
341 sizeof(struct ocfs2_protocol_version))) {
342 rc = -EINVAL;
343 goto out;
344 }
345
346 new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
347 GFP_KERNEL);
348 if (!new_conn) {
349 rc = -ENOMEM;
350 goto out;
351 }
352
353 strlcpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
354 new_conn->cc_namelen = grouplen;
355 if (cluster_name_len)
356 strlcpy(new_conn->cc_cluster_name, cluster_name,
357 CLUSTER_NAME_MAX + 1);
358 new_conn->cc_cluster_name_len = cluster_name_len;
359 new_conn->cc_recovery_handler = recovery_handler;
360 new_conn->cc_recovery_data = recovery_data;
361
362 new_conn->cc_proto = lproto;
363 /* Start the new connection at our maximum compatibility level */
364 new_conn->cc_version = lproto->lp_max_version;
365
366 /* This will pin the stack driver if successful */
367 rc = ocfs2_stack_driver_get(stack_name);
368 if (rc)
369 goto out_free;
370
371 rc = active_stack->sp_ops->connect(new_conn);
372 if (rc) {
373 ocfs2_stack_driver_put();
374 goto out_free;
375 }
376
377 *conn = new_conn;
378
379out_free:
380 if (rc)
381 kfree(new_conn);
382
383out:
384 return rc;
385}
386EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
387
388/* The caller will ensure all nodes have the same cluster stack */
389int ocfs2_cluster_connect_agnostic(const char *group,
390 int grouplen,
391 struct ocfs2_locking_protocol *lproto,
392 void (*recovery_handler)(int node_num,
393 void *recovery_data),
394 void *recovery_data,
395 struct ocfs2_cluster_connection **conn)
396{
397 char *stack_name = NULL;
398
399 if (cluster_stack_name[0])
400 stack_name = cluster_stack_name;
401 return ocfs2_cluster_connect(stack_name, NULL, 0, group, grouplen,
402 lproto, recovery_handler, recovery_data,
403 conn);
404}
405EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
406
407/* If hangup_pending is 0, the stack driver will be dropped */
408int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
409 int hangup_pending)
410{
411 int ret;
412
413 BUG_ON(conn == NULL);
414
415 ret = active_stack->sp_ops->disconnect(conn);
416
417 /* XXX Should we free it anyway? */
418 if (!ret) {
419 kfree(conn);
420 if (!hangup_pending)
421 ocfs2_stack_driver_put();
422 }
423
424 return ret;
425}
426EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
427
428/*
429 * Leave the group for this filesystem. This is executed by a userspace
430 * program (stored in ocfs2_hb_ctl_path).
431 */
432static void ocfs2_leave_group(const char *group)
433{
434 int ret;
435 char *argv[5], *envp[3];
436
437 argv[0] = ocfs2_hb_ctl_path;
438 argv[1] = "-K";
439 argv[2] = "-u";
440 argv[3] = (char *)group;
441 argv[4] = NULL;
442
443 /* minimal command environment taken from cpu_run_sbin_hotplug */
444 envp[0] = "HOME=/";
445 envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
446 envp[2] = NULL;
447
448 ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
449 if (ret < 0) {
450 printk(KERN_ERR
451 "ocfs2: Error %d running user helper "
452 "\"%s %s %s %s\"\n",
453 ret, argv[0], argv[1], argv[2], argv[3]);
454 }
455}
456
457/*
458 * Hangup is a required post-umount. ocfs2-tools software expects the
459 * filesystem to call "ocfs2_hb_ctl" during unmount. This happens
460 * regardless of whether the DLM got started, so we can't do it
461 * in ocfs2_cluster_disconnect(). The ocfs2_leave_group() function does
462 * the actual work.
463 */
464void ocfs2_cluster_hangup(const char *group, int grouplen)
465{
466 BUG_ON(group == NULL);
467 BUG_ON(group[grouplen] != '\0');
468
469 ocfs2_leave_group(group);
470
471 /* cluster_disconnect() was called with hangup_pending==1 */
472 ocfs2_stack_driver_put();
473}
474EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
475
476int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
477 unsigned int *node)
478{
479 return active_stack->sp_ops->this_node(conn, node);
480}
481EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
482
483
484/*
485 * Sysfs bits
486 */
487
488static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
489 struct kobj_attribute *attr,
490 char *buf)
491{
492 ssize_t ret = 0;
493
494 spin_lock(&ocfs2_stack_lock);
495 if (locking_max_version.pv_major)
496 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
497 locking_max_version.pv_major,
498 locking_max_version.pv_minor);
499 spin_unlock(&ocfs2_stack_lock);
500
501 return ret;
502}
503
504static struct kobj_attribute ocfs2_attr_max_locking_protocol =
505 __ATTR(max_locking_protocol, S_IRUGO,
506 ocfs2_max_locking_protocol_show, NULL);
507
508static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
509 struct kobj_attribute *attr,
510 char *buf)
511{
512 ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
513 struct ocfs2_stack_plugin *p;
514
515 spin_lock(&ocfs2_stack_lock);
516 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
517 ret = snprintf(buf, remain, "%s\n",
518 p->sp_name);
519 if (ret < 0) {
520 total = ret;
521 break;
522 }
523 if (ret == remain) {
524 /* snprintf() didn't fit */
525 total = -E2BIG;
526 break;
527 }
528 total += ret;
529 remain -= ret;
530 }
531 spin_unlock(&ocfs2_stack_lock);
532
533 return total;
534}
535
536static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
537 __ATTR(loaded_cluster_plugins, S_IRUGO,
538 ocfs2_loaded_cluster_plugins_show, NULL);
539
540static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
541 struct kobj_attribute *attr,
542 char *buf)
543{
544 ssize_t ret = 0;
545
546 spin_lock(&ocfs2_stack_lock);
547 if (active_stack) {
548 ret = snprintf(buf, PAGE_SIZE, "%s\n",
549 active_stack->sp_name);
550 if (ret == PAGE_SIZE)
551 ret = -E2BIG;
552 }
553 spin_unlock(&ocfs2_stack_lock);
554
555 return ret;
556}
557
558static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
559 __ATTR(active_cluster_plugin, S_IRUGO,
560 ocfs2_active_cluster_plugin_show, NULL);
561
562static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
563 struct kobj_attribute *attr,
564 char *buf)
565{
566 ssize_t ret;
567 spin_lock(&ocfs2_stack_lock);
568 ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
569 spin_unlock(&ocfs2_stack_lock);
570
571 return ret;
572}
573
574static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
575 struct kobj_attribute *attr,
576 const char *buf, size_t count)
577{
578 size_t len = count;
579 ssize_t ret;
580
581 if (len == 0)
582 return len;
583
584 if (buf[len - 1] == '\n')
585 len--;
586
587 if ((len != OCFS2_STACK_LABEL_LEN) ||
588 (strnlen(buf, len) != len))
589 return -EINVAL;
590
591 spin_lock(&ocfs2_stack_lock);
592 if (active_stack) {
593 if (!strncmp(buf, cluster_stack_name, len))
594 ret = count;
595 else
596 ret = -EBUSY;
597 } else {
598 memcpy(cluster_stack_name, buf, len);
599 ret = count;
600 }
601 spin_unlock(&ocfs2_stack_lock);
602
603 return ret;
604}
605
606
607static struct kobj_attribute ocfs2_attr_cluster_stack =
608 __ATTR(cluster_stack, S_IRUGO | S_IWUSR,
609 ocfs2_cluster_stack_show,
610 ocfs2_cluster_stack_store);
611
612
613
614static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
615 struct kobj_attribute *attr,
616 char *buf)
617{
618 return snprintf(buf, PAGE_SIZE, "1\n");
619}
620
621static struct kobj_attribute ocfs2_attr_dlm_recover_support =
622 __ATTR(dlm_recover_callback_support, S_IRUGO,
623 ocfs2_dlm_recover_show, NULL);
624
625static struct attribute *ocfs2_attrs[] = {
626 &ocfs2_attr_max_locking_protocol.attr,
627 &ocfs2_attr_loaded_cluster_plugins.attr,
628 &ocfs2_attr_active_cluster_plugin.attr,
629 &ocfs2_attr_cluster_stack.attr,
630 &ocfs2_attr_dlm_recover_support.attr,
631 NULL,
632};
633
634static const struct attribute_group ocfs2_attr_group = {
635 .attrs = ocfs2_attrs,
636};
637
638struct kset *ocfs2_kset;
639EXPORT_SYMBOL_GPL(ocfs2_kset);
640
641static void ocfs2_sysfs_exit(void)
642{
643 kset_unregister(ocfs2_kset);
644}
645
646static int ocfs2_sysfs_init(void)
647{
648 int ret;
649
650 ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
651 if (!ocfs2_kset)
652 return -ENOMEM;
653
654 ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
655 if (ret)
656 goto error;
657
658 return 0;
659
660error:
661 kset_unregister(ocfs2_kset);
662 return ret;
663}
664
665/*
666 * Sysctl bits
667 *
668 * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path. The 'nm' doesn't
669 * make as much sense in a multiple cluster stack world, but it's safer
670 * and easier to preserve the name.
671 */
672
673#define FS_OCFS2_NM 1
674
675static struct ctl_table ocfs2_nm_table[] = {
676 {
677 .procname = "hb_ctl_path",
678 .data = ocfs2_hb_ctl_path,
679 .maxlen = OCFS2_MAX_HB_CTL_PATH,
680 .mode = 0644,
681 .proc_handler = proc_dostring,
682 },
683 { }
684};
685
686static struct ctl_table ocfs2_mod_table[] = {
687 {
688 .procname = "nm",
689 .data = NULL,
690 .maxlen = 0,
691 .mode = 0555,
692 .child = ocfs2_nm_table
693 },
694 { }
695};
696
697static struct ctl_table ocfs2_kern_table[] = {
698 {
699 .procname = "ocfs2",
700 .data = NULL,
701 .maxlen = 0,
702 .mode = 0555,
703 .child = ocfs2_mod_table
704 },
705 { }
706};
707
708static struct ctl_table ocfs2_root_table[] = {
709 {
710 .procname = "fs",
711 .data = NULL,
712 .maxlen = 0,
713 .mode = 0555,
714 .child = ocfs2_kern_table
715 },
716 { }
717};
718
719static struct ctl_table_header *ocfs2_table_header;
720
721
722/*
723 * Initialization
724 */
725
726static int __init ocfs2_stack_glue_init(void)
727{
728 strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
729
730 ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
731 if (!ocfs2_table_header) {
732 printk(KERN_ERR
733 "ocfs2 stack glue: unable to register sysctl\n");
734 return -ENOMEM; /* or something. */
735 }
736
737 return ocfs2_sysfs_init();
738}
739
740static void __exit ocfs2_stack_glue_exit(void)
741{
742 memset(&locking_max_version, 0,
743 sizeof(struct ocfs2_protocol_version));
744 ocfs2_sysfs_exit();
745 if (ocfs2_table_header)
746 unregister_sysctl_table(ocfs2_table_header);
747}
748
749MODULE_AUTHOR("Oracle");
750MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
751MODULE_LICENSE("GPL");
752module_init(ocfs2_stack_glue_init);
753module_exit(ocfs2_stack_glue_exit);