1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * stackglue.c
4  *
5  * Code which implements an OCFS2 specific interface to underlying
6  * cluster stacks.
7  *
8  * Copyright (C) 2007, 2009 Oracle.  All rights reserved.
9  */
10 
11 #include <linux/list.h>
12 #include <linux/spinlock.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/kmod.h>
16 #include <linux/fs.h>
17 #include <linux/kobject.h>
18 #include <linux/sysfs.h>
19 #include <linux/sysctl.h>
20 
21 #include "ocfs2_fs.h"
22 
23 #include "stackglue.h"
24 
25 #define OCFS2_STACK_PLUGIN_O2CB		"o2cb"
26 #define OCFS2_STACK_PLUGIN_USER		"user"
27 #define OCFS2_MAX_HB_CTL_PATH		256
28 
29 static struct ocfs2_protocol_version locking_max_version;
30 static DEFINE_SPINLOCK(ocfs2_stack_lock);
31 static LIST_HEAD(ocfs2_stack_list);
32 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
33 static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
34 
35 /*
36  * The stack currently in use.  If not null, active_stack->sp_count > 0,
37  * the module is pinned, and the locking protocol cannot be changed.
38  */
39 static struct ocfs2_stack_plugin *active_stack;
40 
ocfs2_stack_lookup(const char * name)41 static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
42 {
43 	struct ocfs2_stack_plugin *p;
44 
45 	assert_spin_locked(&ocfs2_stack_lock);
46 
47 	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
48 		if (!strcmp(p->sp_name, name))
49 			return p;
50 	}
51 
52 	return NULL;
53 }
54 
ocfs2_stack_driver_request(const char * stack_name,const char * plugin_name)55 static int ocfs2_stack_driver_request(const char *stack_name,
56 				      const char *plugin_name)
57 {
58 	int rc;
59 	struct ocfs2_stack_plugin *p;
60 
61 	spin_lock(&ocfs2_stack_lock);
62 
63 	/*
64 	 * If the stack passed by the filesystem isn't the selected one,
65 	 * we can't continue.
66 	 */
67 	if (strcmp(stack_name, cluster_stack_name)) {
68 		rc = -EBUSY;
69 		goto out;
70 	}
71 
72 	if (active_stack) {
73 		/*
74 		 * If the active stack isn't the one we want, it cannot
75 		 * be selected right now.
76 		 */
77 		if (!strcmp(active_stack->sp_name, plugin_name))
78 			rc = 0;
79 		else
80 			rc = -EBUSY;
81 		goto out;
82 	}
83 
84 	p = ocfs2_stack_lookup(plugin_name);
85 	if (!p || !try_module_get(p->sp_owner)) {
86 		rc = -ENOENT;
87 		goto out;
88 	}
89 
90 	active_stack = p;
91 	rc = 0;
92 
93 out:
94 	/* If we found it, pin it */
95 	if (!rc)
96 		active_stack->sp_count++;
97 
98 	spin_unlock(&ocfs2_stack_lock);
99 	return rc;
100 }
101 
102 /*
103  * This function looks up the appropriate stack and makes it active.  If
104  * there is no stack, it tries to load it.  It will fail if the stack still
105  * cannot be found.  It will also fail if a different stack is in use.
106  */
ocfs2_stack_driver_get(const char * stack_name)107 static int ocfs2_stack_driver_get(const char *stack_name)
108 {
109 	int rc;
110 	char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
111 
112 	/*
113 	 * Classic stack does not pass in a stack name.  This is
114 	 * compatible with older tools as well.
115 	 */
116 	if (!stack_name || !*stack_name)
117 		stack_name = OCFS2_STACK_PLUGIN_O2CB;
118 
119 	if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
120 		printk(KERN_ERR
121 		       "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
122 		       stack_name);
123 		return -EINVAL;
124 	}
125 
126 	/* Anything that isn't the classic stack is a user stack */
127 	if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
128 		plugin_name = OCFS2_STACK_PLUGIN_USER;
129 
130 	rc = ocfs2_stack_driver_request(stack_name, plugin_name);
131 	if (rc == -ENOENT) {
132 		request_module("ocfs2_stack_%s", plugin_name);
133 		rc = ocfs2_stack_driver_request(stack_name, plugin_name);
134 	}
135 
136 	if (rc == -ENOENT) {
137 		printk(KERN_ERR
138 		       "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
139 		       plugin_name);
140 	} else if (rc == -EBUSY) {
141 		printk(KERN_ERR
142 		       "ocfs2: A different cluster stack is in use\n");
143 	}
144 
145 	return rc;
146 }
147 
ocfs2_stack_driver_put(void)148 static void ocfs2_stack_driver_put(void)
149 {
150 	spin_lock(&ocfs2_stack_lock);
151 	BUG_ON(active_stack == NULL);
152 	BUG_ON(active_stack->sp_count == 0);
153 
154 	active_stack->sp_count--;
155 	if (!active_stack->sp_count) {
156 		module_put(active_stack->sp_owner);
157 		active_stack = NULL;
158 	}
159 	spin_unlock(&ocfs2_stack_lock);
160 }
161 
ocfs2_stack_glue_register(struct ocfs2_stack_plugin * plugin)162 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
163 {
164 	int rc;
165 
166 	spin_lock(&ocfs2_stack_lock);
167 	if (!ocfs2_stack_lookup(plugin->sp_name)) {
168 		plugin->sp_count = 0;
169 		plugin->sp_max_proto = locking_max_version;
170 		list_add(&plugin->sp_list, &ocfs2_stack_list);
171 		printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
172 		       plugin->sp_name);
173 		rc = 0;
174 	} else {
175 		printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
176 		       plugin->sp_name);
177 		rc = -EEXIST;
178 	}
179 	spin_unlock(&ocfs2_stack_lock);
180 
181 	return rc;
182 }
183 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
184 
ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin * plugin)185 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
186 {
187 	struct ocfs2_stack_plugin *p;
188 
189 	spin_lock(&ocfs2_stack_lock);
190 	p = ocfs2_stack_lookup(plugin->sp_name);
191 	if (p) {
192 		BUG_ON(p != plugin);
193 		BUG_ON(plugin == active_stack);
194 		BUG_ON(plugin->sp_count != 0);
195 		list_del_init(&plugin->sp_list);
196 		printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
197 		       plugin->sp_name);
198 	} else {
199 		printk(KERN_ERR "Stack \"%s\" is not registered\n",
200 		       plugin->sp_name);
201 	}
202 	spin_unlock(&ocfs2_stack_lock);
203 }
204 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
205 
ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version * max_proto)206 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
207 {
208 	struct ocfs2_stack_plugin *p;
209 
210 	spin_lock(&ocfs2_stack_lock);
211 	if (memcmp(max_proto, &locking_max_version,
212 		   sizeof(struct ocfs2_protocol_version))) {
213 		BUG_ON(locking_max_version.pv_major != 0);
214 
215 		locking_max_version = *max_proto;
216 		list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
217 			p->sp_max_proto = locking_max_version;
218 		}
219 	}
220 	spin_unlock(&ocfs2_stack_lock);
221 }
222 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
223 
224 
225 /*
226  * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
227  * for the ast and bast functions.  They will pass the lksb to the ast
228  * and bast.  The caller can wrap the lksb with their own structure to
229  * get more information.
230  */
ocfs2_dlm_lock(struct ocfs2_cluster_connection * conn,int mode,struct ocfs2_dlm_lksb * lksb,u32 flags,void * name,unsigned int namelen)231 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
232 		   int mode,
233 		   struct ocfs2_dlm_lksb *lksb,
234 		   u32 flags,
235 		   void *name,
236 		   unsigned int namelen)
237 {
238 	if (!lksb->lksb_conn)
239 		lksb->lksb_conn = conn;
240 	else
241 		BUG_ON(lksb->lksb_conn != conn);
242 	return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
243 					      name, namelen);
244 }
245 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
246 
ocfs2_dlm_unlock(struct ocfs2_cluster_connection * conn,struct ocfs2_dlm_lksb * lksb,u32 flags)247 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
248 		     struct ocfs2_dlm_lksb *lksb,
249 		     u32 flags)
250 {
251 	BUG_ON(lksb->lksb_conn == NULL);
252 
253 	return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
254 }
255 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
256 
ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb * lksb)257 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
258 {
259 	return active_stack->sp_ops->lock_status(lksb);
260 }
261 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
262 
ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb * lksb)263 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
264 {
265 	return active_stack->sp_ops->lvb_valid(lksb);
266 }
267 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
268 
ocfs2_dlm_lvb(struct ocfs2_dlm_lksb * lksb)269 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
270 {
271 	return active_stack->sp_ops->lock_lvb(lksb);
272 }
273 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
274 
ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb * lksb)275 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
276 {
277 	active_stack->sp_ops->dump_lksb(lksb);
278 }
279 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
280 
ocfs2_stack_supports_plocks(void)281 int ocfs2_stack_supports_plocks(void)
282 {
283 	return active_stack && active_stack->sp_ops->plock;
284 }
285 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
286 
287 /*
288  * ocfs2_plock() can only be safely called if
289  * ocfs2_stack_supports_plocks() returned true
290  */
ocfs2_plock(struct ocfs2_cluster_connection * conn,u64 ino,struct file * file,int cmd,struct file_lock * fl)291 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
292 		struct file *file, int cmd, struct file_lock *fl)
293 {
294 	WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
295 	if (active_stack->sp_ops->plock)
296 		return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
297 	return -EOPNOTSUPP;
298 }
299 EXPORT_SYMBOL_GPL(ocfs2_plock);
300 
ocfs2_cluster_connect(const char * stack_name,const char * cluster_name,int cluster_name_len,const char * group,int grouplen,struct ocfs2_locking_protocol * lproto,void (* recovery_handler)(int node_num,void * recovery_data),void * recovery_data,struct ocfs2_cluster_connection ** conn)301 int ocfs2_cluster_connect(const char *stack_name,
302 			  const char *cluster_name,
303 			  int cluster_name_len,
304 			  const char *group,
305 			  int grouplen,
306 			  struct ocfs2_locking_protocol *lproto,
307 			  void (*recovery_handler)(int node_num,
308 						   void *recovery_data),
309 			  void *recovery_data,
310 			  struct ocfs2_cluster_connection **conn)
311 {
312 	int rc = 0;
313 	struct ocfs2_cluster_connection *new_conn;
314 
315 	BUG_ON(group == NULL);
316 	BUG_ON(conn == NULL);
317 	BUG_ON(recovery_handler == NULL);
318 
319 	if (grouplen > GROUP_NAME_MAX) {
320 		rc = -EINVAL;
321 		goto out;
322 	}
323 
324 	if (memcmp(&lproto->lp_max_version, &locking_max_version,
325 		   sizeof(struct ocfs2_protocol_version))) {
326 		rc = -EINVAL;
327 		goto out;
328 	}
329 
330 	new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
331 			   GFP_KERNEL);
332 	if (!new_conn) {
333 		rc = -ENOMEM;
334 		goto out;
335 	}
336 
337 	strlcpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
338 	new_conn->cc_namelen = grouplen;
339 	if (cluster_name_len)
340 		strlcpy(new_conn->cc_cluster_name, cluster_name,
341 			CLUSTER_NAME_MAX + 1);
342 	new_conn->cc_cluster_name_len = cluster_name_len;
343 	new_conn->cc_recovery_handler = recovery_handler;
344 	new_conn->cc_recovery_data = recovery_data;
345 
346 	new_conn->cc_proto = lproto;
347 	/* Start the new connection at our maximum compatibility level */
348 	new_conn->cc_version = lproto->lp_max_version;
349 
350 	/* This will pin the stack driver if successful */
351 	rc = ocfs2_stack_driver_get(stack_name);
352 	if (rc)
353 		goto out_free;
354 
355 	rc = active_stack->sp_ops->connect(new_conn);
356 	if (rc) {
357 		ocfs2_stack_driver_put();
358 		goto out_free;
359 	}
360 
361 	*conn = new_conn;
362 
363 out_free:
364 	if (rc)
365 		kfree(new_conn);
366 
367 out:
368 	return rc;
369 }
370 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
371 
372 /* The caller will ensure all nodes have the same cluster stack */
ocfs2_cluster_connect_agnostic(const char * group,int grouplen,struct ocfs2_locking_protocol * lproto,void (* recovery_handler)(int node_num,void * recovery_data),void * recovery_data,struct ocfs2_cluster_connection ** conn)373 int ocfs2_cluster_connect_agnostic(const char *group,
374 				   int grouplen,
375 				   struct ocfs2_locking_protocol *lproto,
376 				   void (*recovery_handler)(int node_num,
377 							    void *recovery_data),
378 				   void *recovery_data,
379 				   struct ocfs2_cluster_connection **conn)
380 {
381 	char *stack_name = NULL;
382 
383 	if (cluster_stack_name[0])
384 		stack_name = cluster_stack_name;
385 	return ocfs2_cluster_connect(stack_name, NULL, 0, group, grouplen,
386 				     lproto, recovery_handler, recovery_data,
387 				     conn);
388 }
389 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
390 
391 /* If hangup_pending is 0, the stack driver will be dropped */
ocfs2_cluster_disconnect(struct ocfs2_cluster_connection * conn,int hangup_pending)392 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
393 			     int hangup_pending)
394 {
395 	int ret;
396 
397 	BUG_ON(conn == NULL);
398 
399 	ret = active_stack->sp_ops->disconnect(conn);
400 
401 	/* XXX Should we free it anyway? */
402 	if (!ret) {
403 		kfree(conn);
404 		if (!hangup_pending)
405 			ocfs2_stack_driver_put();
406 	}
407 
408 	return ret;
409 }
410 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
411 
412 /*
413  * Leave the group for this filesystem.  This is executed by a userspace
414  * program (stored in ocfs2_hb_ctl_path).
415  */
ocfs2_leave_group(const char * group)416 static void ocfs2_leave_group(const char *group)
417 {
418 	int ret;
419 	char *argv[5], *envp[3];
420 
421 	argv[0] = ocfs2_hb_ctl_path;
422 	argv[1] = "-K";
423 	argv[2] = "-u";
424 	argv[3] = (char *)group;
425 	argv[4] = NULL;
426 
427 	/* minimal command environment taken from cpu_run_sbin_hotplug */
428 	envp[0] = "HOME=/";
429 	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
430 	envp[2] = NULL;
431 
432 	ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
433 	if (ret < 0) {
434 		printk(KERN_ERR
435 		       "ocfs2: Error %d running user helper "
436 		       "\"%s %s %s %s\"\n",
437 		       ret, argv[0], argv[1], argv[2], argv[3]);
438 	}
439 }
440 
441 /*
442  * Hangup is a required post-umount.  ocfs2-tools software expects the
443  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
444  * regardless of whether the DLM got started, so we can't do it
445  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
446  * the actual work.
447  */
ocfs2_cluster_hangup(const char * group,int grouplen)448 void ocfs2_cluster_hangup(const char *group, int grouplen)
449 {
450 	BUG_ON(group == NULL);
451 	BUG_ON(group[grouplen] != '\0');
452 
453 	ocfs2_leave_group(group);
454 
455 	/* cluster_disconnect() was called with hangup_pending==1 */
456 	ocfs2_stack_driver_put();
457 }
458 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
459 
ocfs2_cluster_this_node(struct ocfs2_cluster_connection * conn,unsigned int * node)460 int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
461 			    unsigned int *node)
462 {
463 	return active_stack->sp_ops->this_node(conn, node);
464 }
465 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
466 
467 
468 /*
469  * Sysfs bits
470  */
471 
ocfs2_max_locking_protocol_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)472 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
473 					       struct kobj_attribute *attr,
474 					       char *buf)
475 {
476 	ssize_t ret = 0;
477 
478 	spin_lock(&ocfs2_stack_lock);
479 	if (locking_max_version.pv_major)
480 		ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
481 			       locking_max_version.pv_major,
482 			       locking_max_version.pv_minor);
483 	spin_unlock(&ocfs2_stack_lock);
484 
485 	return ret;
486 }
487 
488 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
489 	__ATTR(max_locking_protocol, S_IRUGO,
490 	       ocfs2_max_locking_protocol_show, NULL);
491 
ocfs2_loaded_cluster_plugins_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)492 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
493 						 struct kobj_attribute *attr,
494 						 char *buf)
495 {
496 	ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
497 	struct ocfs2_stack_plugin *p;
498 
499 	spin_lock(&ocfs2_stack_lock);
500 	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
501 		ret = snprintf(buf, remain, "%s\n",
502 			       p->sp_name);
503 		if (ret >= remain) {
504 			/* snprintf() didn't fit */
505 			total = -E2BIG;
506 			break;
507 		}
508 		total += ret;
509 		remain -= ret;
510 	}
511 	spin_unlock(&ocfs2_stack_lock);
512 
513 	return total;
514 }
515 
516 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
517 	__ATTR(loaded_cluster_plugins, S_IRUGO,
518 	       ocfs2_loaded_cluster_plugins_show, NULL);
519 
ocfs2_active_cluster_plugin_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)520 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
521 						struct kobj_attribute *attr,
522 						char *buf)
523 {
524 	ssize_t ret = 0;
525 
526 	spin_lock(&ocfs2_stack_lock);
527 	if (active_stack) {
528 		ret = snprintf(buf, PAGE_SIZE, "%s\n",
529 			       active_stack->sp_name);
530 		if (ret >= PAGE_SIZE)
531 			ret = -E2BIG;
532 	}
533 	spin_unlock(&ocfs2_stack_lock);
534 
535 	return ret;
536 }
537 
538 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
539 	__ATTR(active_cluster_plugin, S_IRUGO,
540 	       ocfs2_active_cluster_plugin_show, NULL);
541 
ocfs2_cluster_stack_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)542 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
543 					struct kobj_attribute *attr,
544 					char *buf)
545 {
546 	ssize_t ret;
547 	spin_lock(&ocfs2_stack_lock);
548 	ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
549 	spin_unlock(&ocfs2_stack_lock);
550 
551 	return ret;
552 }
553 
ocfs2_cluster_stack_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)554 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
555 					 struct kobj_attribute *attr,
556 					 const char *buf, size_t count)
557 {
558 	size_t len = count;
559 	ssize_t ret;
560 
561 	if (len == 0)
562 		return len;
563 
564 	if (buf[len - 1] == '\n')
565 		len--;
566 
567 	if ((len != OCFS2_STACK_LABEL_LEN) ||
568 	    (strnlen(buf, len) != len))
569 		return -EINVAL;
570 
571 	spin_lock(&ocfs2_stack_lock);
572 	if (active_stack) {
573 		if (!strncmp(buf, cluster_stack_name, len))
574 			ret = count;
575 		else
576 			ret = -EBUSY;
577 	} else {
578 		memcpy(cluster_stack_name, buf, len);
579 		ret = count;
580 	}
581 	spin_unlock(&ocfs2_stack_lock);
582 
583 	return ret;
584 }
585 
586 
587 static struct kobj_attribute ocfs2_attr_cluster_stack =
588 	__ATTR(cluster_stack, S_IRUGO | S_IWUSR,
589 	       ocfs2_cluster_stack_show,
590 	       ocfs2_cluster_stack_store);
591 
592 
593 
ocfs2_dlm_recover_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)594 static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
595 					struct kobj_attribute *attr,
596 					char *buf)
597 {
598 	return snprintf(buf, PAGE_SIZE, "1\n");
599 }
600 
601 static struct kobj_attribute ocfs2_attr_dlm_recover_support =
602 	__ATTR(dlm_recover_callback_support, S_IRUGO,
603 	       ocfs2_dlm_recover_show, NULL);
604 
605 static struct attribute *ocfs2_attrs[] = {
606 	&ocfs2_attr_max_locking_protocol.attr,
607 	&ocfs2_attr_loaded_cluster_plugins.attr,
608 	&ocfs2_attr_active_cluster_plugin.attr,
609 	&ocfs2_attr_cluster_stack.attr,
610 	&ocfs2_attr_dlm_recover_support.attr,
611 	NULL,
612 };
613 
614 static const struct attribute_group ocfs2_attr_group = {
615 	.attrs = ocfs2_attrs,
616 };
617 
618 struct kset *ocfs2_kset;
619 EXPORT_SYMBOL_GPL(ocfs2_kset);
620 
ocfs2_sysfs_exit(void)621 static void ocfs2_sysfs_exit(void)
622 {
623 	kset_unregister(ocfs2_kset);
624 }
625 
ocfs2_sysfs_init(void)626 static int ocfs2_sysfs_init(void)
627 {
628 	int ret;
629 
630 	ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
631 	if (!ocfs2_kset)
632 		return -ENOMEM;
633 
634 	ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
635 	if (ret)
636 		goto error;
637 
638 	return 0;
639 
640 error:
641 	kset_unregister(ocfs2_kset);
642 	return ret;
643 }
644 
645 /*
646  * Sysctl bits
647  *
648  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
649  * make as much sense in a multiple cluster stack world, but it's safer
650  * and easier to preserve the name.
651  */
652 
653 static struct ctl_table ocfs2_nm_table[] = {
654 	{
655 		.procname	= "hb_ctl_path",
656 		.data		= ocfs2_hb_ctl_path,
657 		.maxlen		= OCFS2_MAX_HB_CTL_PATH,
658 		.mode		= 0644,
659 		.proc_handler	= proc_dostring,
660 	},
661 	{ }
662 };
663 
664 static struct ctl_table_header *ocfs2_table_header;
665 
666 /*
667  * Initialization
668  */
669 
ocfs2_stack_glue_init(void)670 static int __init ocfs2_stack_glue_init(void)
671 {
672 	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
673 
674 	ocfs2_table_header = register_sysctl("fs/ocfs2/nm", ocfs2_nm_table);
675 	if (!ocfs2_table_header) {
676 		printk(KERN_ERR
677 		       "ocfs2 stack glue: unable to register sysctl\n");
678 		return -ENOMEM; /* or something. */
679 	}
680 
681 	return ocfs2_sysfs_init();
682 }
683 
ocfs2_stack_glue_exit(void)684 static void __exit ocfs2_stack_glue_exit(void)
685 {
686 	memset(&locking_max_version, 0,
687 	       sizeof(struct ocfs2_protocol_version));
688 	ocfs2_sysfs_exit();
689 	if (ocfs2_table_header)
690 		unregister_sysctl_table(ocfs2_table_header);
691 }
692 
693 MODULE_AUTHOR("Oracle");
694 MODULE_DESCRIPTION("ocfs2 cluster stack glue layer");
695 MODULE_LICENSE("GPL");
696 module_init(ocfs2_stack_glue_init);
697 module_exit(ocfs2_stack_glue_exit);
698