1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * stackglue.c
5  *
6  * Code which implements an OCFS2 specific interface to underlying
7  * cluster stacks.
8  *
9  * Copyright (C) 2007, 2009 Oracle.  All rights reserved.
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public
13  * License as published by the Free Software Foundation, version 2.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  */
20 
21 #include <linux/list.h>
22 #include <linux/spinlock.h>
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/kmod.h>
26 #include <linux/fs.h>
27 #include <linux/kobject.h>
28 #include <linux/sysfs.h>
29 #include <linux/sysctl.h>
30 
31 #include "ocfs2_fs.h"
32 
33 #include "stackglue.h"
34 
35 #define OCFS2_STACK_PLUGIN_O2CB		"o2cb"
36 #define OCFS2_STACK_PLUGIN_USER		"user"
37 #define OCFS2_MAX_HB_CTL_PATH		256
38 
39 static struct ocfs2_protocol_version locking_max_version;
40 static DEFINE_SPINLOCK(ocfs2_stack_lock);
41 static LIST_HEAD(ocfs2_stack_list);
42 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
43 static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
44 
45 /*
46  * The stack currently in use.  If not null, active_stack->sp_count > 0,
47  * the module is pinned, and the locking protocol cannot be changed.
48  */
49 static struct ocfs2_stack_plugin *active_stack;
50 
ocfs2_stack_lookup(const char * name)51 static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
52 {
53 	struct ocfs2_stack_plugin *p;
54 
55 	assert_spin_locked(&ocfs2_stack_lock);
56 
57 	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
58 		if (!strcmp(p->sp_name, name))
59 			return p;
60 	}
61 
62 	return NULL;
63 }
64 
ocfs2_stack_driver_request(const char * stack_name,const char * plugin_name)65 static int ocfs2_stack_driver_request(const char *stack_name,
66 				      const char *plugin_name)
67 {
68 	int rc;
69 	struct ocfs2_stack_plugin *p;
70 
71 	spin_lock(&ocfs2_stack_lock);
72 
73 	/*
74 	 * If the stack passed by the filesystem isn't the selected one,
75 	 * we can't continue.
76 	 */
77 	if (strcmp(stack_name, cluster_stack_name)) {
78 		rc = -EBUSY;
79 		goto out;
80 	}
81 
82 	if (active_stack) {
83 		/*
84 		 * If the active stack isn't the one we want, it cannot
85 		 * be selected right now.
86 		 */
87 		if (!strcmp(active_stack->sp_name, plugin_name))
88 			rc = 0;
89 		else
90 			rc = -EBUSY;
91 		goto out;
92 	}
93 
94 	p = ocfs2_stack_lookup(plugin_name);
95 	if (!p || !try_module_get(p->sp_owner)) {
96 		rc = -ENOENT;
97 		goto out;
98 	}
99 
100 	active_stack = p;
101 	rc = 0;
102 
103 out:
104 	/* If we found it, pin it */
105 	if (!rc)
106 		active_stack->sp_count++;
107 
108 	spin_unlock(&ocfs2_stack_lock);
109 	return rc;
110 }
111 
112 /*
113  * This function looks up the appropriate stack and makes it active.  If
114  * there is no stack, it tries to load it.  It will fail if the stack still
115  * cannot be found.  It will also fail if a different stack is in use.
116  */
ocfs2_stack_driver_get(const char * stack_name)117 static int ocfs2_stack_driver_get(const char *stack_name)
118 {
119 	int rc;
120 	char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
121 
122 	/*
123 	 * Classic stack does not pass in a stack name.  This is
124 	 * compatible with older tools as well.
125 	 */
126 	if (!stack_name || !*stack_name)
127 		stack_name = OCFS2_STACK_PLUGIN_O2CB;
128 
129 	if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
130 		printk(KERN_ERR
131 		       "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
132 		       stack_name);
133 		return -EINVAL;
134 	}
135 
136 	/* Anything that isn't the classic stack is a user stack */
137 	if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
138 		plugin_name = OCFS2_STACK_PLUGIN_USER;
139 
140 	rc = ocfs2_stack_driver_request(stack_name, plugin_name);
141 	if (rc == -ENOENT) {
142 		request_module("ocfs2_stack_%s", plugin_name);
143 		rc = ocfs2_stack_driver_request(stack_name, plugin_name);
144 	}
145 
146 	if (rc == -ENOENT) {
147 		printk(KERN_ERR
148 		       "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
149 		       plugin_name);
150 	} else if (rc == -EBUSY) {
151 		printk(KERN_ERR
152 		       "ocfs2: A different cluster stack is in use\n");
153 	}
154 
155 	return rc;
156 }
157 
ocfs2_stack_driver_put(void)158 static void ocfs2_stack_driver_put(void)
159 {
160 	spin_lock(&ocfs2_stack_lock);
161 	BUG_ON(active_stack == NULL);
162 	BUG_ON(active_stack->sp_count == 0);
163 
164 	active_stack->sp_count--;
165 	if (!active_stack->sp_count) {
166 		module_put(active_stack->sp_owner);
167 		active_stack = NULL;
168 	}
169 	spin_unlock(&ocfs2_stack_lock);
170 }
171 
ocfs2_stack_glue_register(struct ocfs2_stack_plugin * plugin)172 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
173 {
174 	int rc;
175 
176 	spin_lock(&ocfs2_stack_lock);
177 	if (!ocfs2_stack_lookup(plugin->sp_name)) {
178 		plugin->sp_count = 0;
179 		plugin->sp_max_proto = locking_max_version;
180 		list_add(&plugin->sp_list, &ocfs2_stack_list);
181 		printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
182 		       plugin->sp_name);
183 		rc = 0;
184 	} else {
185 		printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
186 		       plugin->sp_name);
187 		rc = -EEXIST;
188 	}
189 	spin_unlock(&ocfs2_stack_lock);
190 
191 	return rc;
192 }
193 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
194 
ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin * plugin)195 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
196 {
197 	struct ocfs2_stack_plugin *p;
198 
199 	spin_lock(&ocfs2_stack_lock);
200 	p = ocfs2_stack_lookup(plugin->sp_name);
201 	if (p) {
202 		BUG_ON(p != plugin);
203 		BUG_ON(plugin == active_stack);
204 		BUG_ON(plugin->sp_count != 0);
205 		list_del_init(&plugin->sp_list);
206 		printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
207 		       plugin->sp_name);
208 	} else {
209 		printk(KERN_ERR "Stack \"%s\" is not registered\n",
210 		       plugin->sp_name);
211 	}
212 	spin_unlock(&ocfs2_stack_lock);
213 }
214 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
215 
ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version * max_proto)216 void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
217 {
218 	struct ocfs2_stack_plugin *p;
219 
220 	spin_lock(&ocfs2_stack_lock);
221 	if (memcmp(max_proto, &locking_max_version,
222 		   sizeof(struct ocfs2_protocol_version))) {
223 		BUG_ON(locking_max_version.pv_major != 0);
224 
225 		locking_max_version = *max_proto;
226 		list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
227 			p->sp_max_proto = locking_max_version;
228 		}
229 	}
230 	spin_unlock(&ocfs2_stack_lock);
231 }
232 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
233 
234 
235 /*
236  * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
237  * for the ast and bast functions.  They will pass the lksb to the ast
238  * and bast.  The caller can wrap the lksb with their own structure to
239  * get more information.
240  */
ocfs2_dlm_lock(struct ocfs2_cluster_connection * conn,int mode,struct ocfs2_dlm_lksb * lksb,u32 flags,void * name,unsigned int namelen)241 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
242 		   int mode,
243 		   struct ocfs2_dlm_lksb *lksb,
244 		   u32 flags,
245 		   void *name,
246 		   unsigned int namelen)
247 {
248 	if (!lksb->lksb_conn)
249 		lksb->lksb_conn = conn;
250 	else
251 		BUG_ON(lksb->lksb_conn != conn);
252 	return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
253 					      name, namelen);
254 }
255 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
256 
ocfs2_dlm_unlock(struct ocfs2_cluster_connection * conn,struct ocfs2_dlm_lksb * lksb,u32 flags)257 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
258 		     struct ocfs2_dlm_lksb *lksb,
259 		     u32 flags)
260 {
261 	BUG_ON(lksb->lksb_conn == NULL);
262 
263 	return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
264 }
265 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
266 
ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb * lksb)267 int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
268 {
269 	return active_stack->sp_ops->lock_status(lksb);
270 }
271 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
272 
ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb * lksb)273 int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
274 {
275 	return active_stack->sp_ops->lvb_valid(lksb);
276 }
277 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
278 
ocfs2_dlm_lvb(struct ocfs2_dlm_lksb * lksb)279 void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
280 {
281 	return active_stack->sp_ops->lock_lvb(lksb);
282 }
283 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
284 
ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb * lksb)285 void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
286 {
287 	active_stack->sp_ops->dump_lksb(lksb);
288 }
289 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
290 
ocfs2_stack_supports_plocks(void)291 int ocfs2_stack_supports_plocks(void)
292 {
293 	return active_stack && active_stack->sp_ops->plock;
294 }
295 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
296 
297 /*
298  * ocfs2_plock() can only be safely called if
299  * ocfs2_stack_supports_plocks() returned true
300  */
ocfs2_plock(struct ocfs2_cluster_connection * conn,u64 ino,struct file * file,int cmd,struct file_lock * fl)301 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
302 		struct file *file, int cmd, struct file_lock *fl)
303 {
304 	WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
305 	if (active_stack->sp_ops->plock)
306 		return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
307 	return -EOPNOTSUPP;
308 }
309 EXPORT_SYMBOL_GPL(ocfs2_plock);
310 
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)311 int ocfs2_cluster_connect(const char *stack_name,
312 			  const char *cluster_name,
313 			  int cluster_name_len,
314 			  const char *group,
315 			  int grouplen,
316 			  struct ocfs2_locking_protocol *lproto,
317 			  void (*recovery_handler)(int node_num,
318 						   void *recovery_data),
319 			  void *recovery_data,
320 			  struct ocfs2_cluster_connection **conn)
321 {
322 	int rc = 0;
323 	struct ocfs2_cluster_connection *new_conn;
324 
325 	BUG_ON(group == NULL);
326 	BUG_ON(conn == NULL);
327 	BUG_ON(recovery_handler == NULL);
328 
329 	if (grouplen > GROUP_NAME_MAX) {
330 		rc = -EINVAL;
331 		goto out;
332 	}
333 
334 	if (memcmp(&lproto->lp_max_version, &locking_max_version,
335 		   sizeof(struct ocfs2_protocol_version))) {
336 		rc = -EINVAL;
337 		goto out;
338 	}
339 
340 	new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
341 			   GFP_KERNEL);
342 	if (!new_conn) {
343 		rc = -ENOMEM;
344 		goto out;
345 	}
346 
347 	strlcpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
348 	new_conn->cc_namelen = grouplen;
349 	if (cluster_name_len)
350 		strlcpy(new_conn->cc_cluster_name, cluster_name,
351 			CLUSTER_NAME_MAX + 1);
352 	new_conn->cc_cluster_name_len = cluster_name_len;
353 	new_conn->cc_recovery_handler = recovery_handler;
354 	new_conn->cc_recovery_data = recovery_data;
355 
356 	new_conn->cc_proto = lproto;
357 	/* Start the new connection at our maximum compatibility level */
358 	new_conn->cc_version = lproto->lp_max_version;
359 
360 	/* This will pin the stack driver if successful */
361 	rc = ocfs2_stack_driver_get(stack_name);
362 	if (rc)
363 		goto out_free;
364 
365 	rc = active_stack->sp_ops->connect(new_conn);
366 	if (rc) {
367 		ocfs2_stack_driver_put();
368 		goto out_free;
369 	}
370 
371 	*conn = new_conn;
372 
373 out_free:
374 	if (rc)
375 		kfree(new_conn);
376 
377 out:
378 	return rc;
379 }
380 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
381 
382 /* The caller will ensure all nodes have the same cluster stack */
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)383 int ocfs2_cluster_connect_agnostic(const char *group,
384 				   int grouplen,
385 				   struct ocfs2_locking_protocol *lproto,
386 				   void (*recovery_handler)(int node_num,
387 							    void *recovery_data),
388 				   void *recovery_data,
389 				   struct ocfs2_cluster_connection **conn)
390 {
391 	char *stack_name = NULL;
392 
393 	if (cluster_stack_name[0])
394 		stack_name = cluster_stack_name;
395 	return ocfs2_cluster_connect(stack_name, NULL, 0, group, grouplen,
396 				     lproto, recovery_handler, recovery_data,
397 				     conn);
398 }
399 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
400 
401 /* If hangup_pending is 0, the stack driver will be dropped */
ocfs2_cluster_disconnect(struct ocfs2_cluster_connection * conn,int hangup_pending)402 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
403 			     int hangup_pending)
404 {
405 	int ret;
406 
407 	BUG_ON(conn == NULL);
408 
409 	ret = active_stack->sp_ops->disconnect(conn);
410 
411 	/* XXX Should we free it anyway? */
412 	if (!ret) {
413 		kfree(conn);
414 		if (!hangup_pending)
415 			ocfs2_stack_driver_put();
416 	}
417 
418 	return ret;
419 }
420 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
421 
422 /*
423  * Leave the group for this filesystem.  This is executed by a userspace
424  * program (stored in ocfs2_hb_ctl_path).
425  */
ocfs2_leave_group(const char * group)426 static void ocfs2_leave_group(const char *group)
427 {
428 	int ret;
429 	char *argv[5], *envp[3];
430 
431 	argv[0] = ocfs2_hb_ctl_path;
432 	argv[1] = "-K";
433 	argv[2] = "-u";
434 	argv[3] = (char *)group;
435 	argv[4] = NULL;
436 
437 	/* minimal command environment taken from cpu_run_sbin_hotplug */
438 	envp[0] = "HOME=/";
439 	envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
440 	envp[2] = NULL;
441 
442 	ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
443 	if (ret < 0) {
444 		printk(KERN_ERR
445 		       "ocfs2: Error %d running user helper "
446 		       "\"%s %s %s %s\"\n",
447 		       ret, argv[0], argv[1], argv[2], argv[3]);
448 	}
449 }
450 
451 /*
452  * Hangup is a required post-umount.  ocfs2-tools software expects the
453  * filesystem to call "ocfs2_hb_ctl" during unmount.  This happens
454  * regardless of whether the DLM got started, so we can't do it
455  * in ocfs2_cluster_disconnect().  The ocfs2_leave_group() function does
456  * the actual work.
457  */
ocfs2_cluster_hangup(const char * group,int grouplen)458 void ocfs2_cluster_hangup(const char *group, int grouplen)
459 {
460 	BUG_ON(group == NULL);
461 	BUG_ON(group[grouplen] != '\0');
462 
463 	ocfs2_leave_group(group);
464 
465 	/* cluster_disconnect() was called with hangup_pending==1 */
466 	ocfs2_stack_driver_put();
467 }
468 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
469 
ocfs2_cluster_this_node(struct ocfs2_cluster_connection * conn,unsigned int * node)470 int ocfs2_cluster_this_node(struct ocfs2_cluster_connection *conn,
471 			    unsigned int *node)
472 {
473 	return active_stack->sp_ops->this_node(conn, node);
474 }
475 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
476 
477 
478 /*
479  * Sysfs bits
480  */
481 
ocfs2_max_locking_protocol_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)482 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
483 					       struct kobj_attribute *attr,
484 					       char *buf)
485 {
486 	ssize_t ret = 0;
487 
488 	spin_lock(&ocfs2_stack_lock);
489 	if (locking_max_version.pv_major)
490 		ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
491 			       locking_max_version.pv_major,
492 			       locking_max_version.pv_minor);
493 	spin_unlock(&ocfs2_stack_lock);
494 
495 	return ret;
496 }
497 
498 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
499 	__ATTR(max_locking_protocol, S_IRUGO,
500 	       ocfs2_max_locking_protocol_show, NULL);
501 
ocfs2_loaded_cluster_plugins_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)502 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
503 						 struct kobj_attribute *attr,
504 						 char *buf)
505 {
506 	ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
507 	struct ocfs2_stack_plugin *p;
508 
509 	spin_lock(&ocfs2_stack_lock);
510 	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
511 		ret = snprintf(buf, remain, "%s\n",
512 			       p->sp_name);
513 		if (ret >= remain) {
514 			/* snprintf() didn't fit */
515 			total = -E2BIG;
516 			break;
517 		}
518 		total += ret;
519 		remain -= ret;
520 	}
521 	spin_unlock(&ocfs2_stack_lock);
522 
523 	return total;
524 }
525 
526 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
527 	__ATTR(loaded_cluster_plugins, S_IRUGO,
528 	       ocfs2_loaded_cluster_plugins_show, NULL);
529 
ocfs2_active_cluster_plugin_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)530 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
531 						struct kobj_attribute *attr,
532 						char *buf)
533 {
534 	ssize_t ret = 0;
535 
536 	spin_lock(&ocfs2_stack_lock);
537 	if (active_stack) {
538 		ret = snprintf(buf, PAGE_SIZE, "%s\n",
539 			       active_stack->sp_name);
540 		if (ret >= PAGE_SIZE)
541 			ret = -E2BIG;
542 	}
543 	spin_unlock(&ocfs2_stack_lock);
544 
545 	return ret;
546 }
547 
548 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
549 	__ATTR(active_cluster_plugin, S_IRUGO,
550 	       ocfs2_active_cluster_plugin_show, NULL);
551 
ocfs2_cluster_stack_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)552 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
553 					struct kobj_attribute *attr,
554 					char *buf)
555 {
556 	ssize_t ret;
557 	spin_lock(&ocfs2_stack_lock);
558 	ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
559 	spin_unlock(&ocfs2_stack_lock);
560 
561 	return ret;
562 }
563 
ocfs2_cluster_stack_store(struct kobject * kobj,struct kobj_attribute * attr,const char * buf,size_t count)564 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
565 					 struct kobj_attribute *attr,
566 					 const char *buf, size_t count)
567 {
568 	size_t len = count;
569 	ssize_t ret;
570 
571 	if (len == 0)
572 		return len;
573 
574 	if (buf[len - 1] == '\n')
575 		len--;
576 
577 	if ((len != OCFS2_STACK_LABEL_LEN) ||
578 	    (strnlen(buf, len) != len))
579 		return -EINVAL;
580 
581 	spin_lock(&ocfs2_stack_lock);
582 	if (active_stack) {
583 		if (!strncmp(buf, cluster_stack_name, len))
584 			ret = count;
585 		else
586 			ret = -EBUSY;
587 	} else {
588 		memcpy(cluster_stack_name, buf, len);
589 		ret = count;
590 	}
591 	spin_unlock(&ocfs2_stack_lock);
592 
593 	return ret;
594 }
595 
596 
597 static struct kobj_attribute ocfs2_attr_cluster_stack =
598 	__ATTR(cluster_stack, S_IRUGO | S_IWUSR,
599 	       ocfs2_cluster_stack_show,
600 	       ocfs2_cluster_stack_store);
601 
602 
603 
ocfs2_dlm_recover_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)604 static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
605 					struct kobj_attribute *attr,
606 					char *buf)
607 {
608 	return snprintf(buf, PAGE_SIZE, "1\n");
609 }
610 
611 static struct kobj_attribute ocfs2_attr_dlm_recover_support =
612 	__ATTR(dlm_recover_callback_support, S_IRUGO,
613 	       ocfs2_dlm_recover_show, NULL);
614 
615 static struct attribute *ocfs2_attrs[] = {
616 	&ocfs2_attr_max_locking_protocol.attr,
617 	&ocfs2_attr_loaded_cluster_plugins.attr,
618 	&ocfs2_attr_active_cluster_plugin.attr,
619 	&ocfs2_attr_cluster_stack.attr,
620 	&ocfs2_attr_dlm_recover_support.attr,
621 	NULL,
622 };
623 
624 static const struct attribute_group ocfs2_attr_group = {
625 	.attrs = ocfs2_attrs,
626 };
627 
628 struct kset *ocfs2_kset;
629 EXPORT_SYMBOL_GPL(ocfs2_kset);
630 
ocfs2_sysfs_exit(void)631 static void ocfs2_sysfs_exit(void)
632 {
633 	kset_unregister(ocfs2_kset);
634 }
635 
ocfs2_sysfs_init(void)636 static int ocfs2_sysfs_init(void)
637 {
638 	int ret;
639 
640 	ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
641 	if (!ocfs2_kset)
642 		return -ENOMEM;
643 
644 	ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
645 	if (ret)
646 		goto error;
647 
648 	return 0;
649 
650 error:
651 	kset_unregister(ocfs2_kset);
652 	return ret;
653 }
654 
655 /*
656  * Sysctl bits
657  *
658  * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path.  The 'nm' doesn't
659  * make as much sense in a multiple cluster stack world, but it's safer
660  * and easier to preserve the name.
661  */
662 
663 #define FS_OCFS2_NM		1
664 
665 static struct ctl_table ocfs2_nm_table[] = {
666 	{
667 		.procname	= "hb_ctl_path",
668 		.data		= ocfs2_hb_ctl_path,
669 		.maxlen		= OCFS2_MAX_HB_CTL_PATH,
670 		.mode		= 0644,
671 		.proc_handler	= proc_dostring,
672 	},
673 	{ }
674 };
675 
676 static struct ctl_table ocfs2_mod_table[] = {
677 	{
678 		.procname	= "nm",
679 		.data		= NULL,
680 		.maxlen		= 0,
681 		.mode		= 0555,
682 		.child		= ocfs2_nm_table
683 	},
684 	{ }
685 };
686 
687 static struct ctl_table ocfs2_kern_table[] = {
688 	{
689 		.procname	= "ocfs2",
690 		.data		= NULL,
691 		.maxlen		= 0,
692 		.mode		= 0555,
693 		.child		= ocfs2_mod_table
694 	},
695 	{ }
696 };
697 
698 static struct ctl_table ocfs2_root_table[] = {
699 	{
700 		.procname	= "fs",
701 		.data		= NULL,
702 		.maxlen		= 0,
703 		.mode		= 0555,
704 		.child		= ocfs2_kern_table
705 	},
706 	{ }
707 };
708 
709 static struct ctl_table_header *ocfs2_table_header;
710 
711 
712 /*
713  * Initialization
714  */
715 
ocfs2_stack_glue_init(void)716 static int __init ocfs2_stack_glue_init(void)
717 {
718 	int ret;
719 
720 	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
721 
722 	ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
723 	if (!ocfs2_table_header) {
724 		printk(KERN_ERR
725 		       "ocfs2 stack glue: unable to register sysctl\n");
726 		return -ENOMEM; /* or something. */
727 	}
728 
729 	ret = ocfs2_sysfs_init();
730 	if (ret)
731 		unregister_sysctl_table(ocfs2_table_header);
732 
733 	return ret;
734 }
735 
ocfs2_stack_glue_exit(void)736 static void __exit ocfs2_stack_glue_exit(void)
737 {
738 	memset(&locking_max_version, 0,
739 	       sizeof(struct ocfs2_protocol_version));
740 	ocfs2_sysfs_exit();
741 	if (ocfs2_table_header)
742 		unregister_sysctl_table(ocfs2_table_header);
743 }
744 
745 MODULE_AUTHOR("Oracle");
746 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
747 MODULE_LICENSE("GPL");
748 module_init(ocfs2_stack_glue_init);
749 module_exit(ocfs2_stack_glue_exit);
750