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  	strscpy(new_conn->cc_name, group, GROUP_NAME_MAX + 1);
338  	new_conn->cc_namelen = grouplen;
339  	if (cluster_name_len)
340  		strscpy(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  static struct ctl_table_header *ocfs2_table_header;
664  
665  /*
666   * Initialization
667   */
668  
ocfs2_stack_glue_init(void)669  static int __init ocfs2_stack_glue_init(void)
670  {
671  	int ret;
672  
673  	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
674  
675  	ocfs2_table_header = register_sysctl("fs/ocfs2/nm", ocfs2_nm_table);
676  	if (!ocfs2_table_header) {
677  		printk(KERN_ERR
678  		       "ocfs2 stack glue: unable to register sysctl\n");
679  		return -ENOMEM; /* or something. */
680  	}
681  
682  	ret = ocfs2_sysfs_init();
683  	if (ret)
684  		unregister_sysctl_table(ocfs2_table_header);
685  
686  	return ret;
687  }
688  
ocfs2_stack_glue_exit(void)689  static void __exit ocfs2_stack_glue_exit(void)
690  {
691  	memset(&locking_max_version, 0,
692  	       sizeof(struct ocfs2_protocol_version));
693  	ocfs2_sysfs_exit();
694  	if (ocfs2_table_header)
695  		unregister_sysctl_table(ocfs2_table_header);
696  }
697  
698  MODULE_AUTHOR("Oracle");
699  MODULE_DESCRIPTION("ocfs2 cluster stack glue layer");
700  MODULE_LICENSE("GPL");
701  module_init(ocfs2_stack_glue_init);
702  module_exit(ocfs2_stack_glue_exit);
703