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
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
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 */
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
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
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
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
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 */
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
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
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
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
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
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
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 */
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
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 */
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 */
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 */
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 */
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
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
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
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
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
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
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
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
621 static void ocfs2_sysfs_exit(void)
622 {
623 kset_unregister(ocfs2_kset);
624 }
625
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
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
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
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.