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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/string.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/kmod.h>
17#include <linux/fs.h>
18#include <linux/kobject.h>
19#include <linux/sysfs.h>
20#include <linux/sysctl.h>
21
22#include "ocfs2_fs.h"
23
24#include "stackglue.h"
25
26#define OCFS2_STACK_PLUGIN_O2CB "o2cb"
27#define OCFS2_STACK_PLUGIN_USER "user"
28#define OCFS2_MAX_HB_CTL_PATH 256
29
30static struct ocfs2_protocol_version locking_max_version;
31static DEFINE_SPINLOCK(ocfs2_stack_lock);
32static LIST_HEAD(ocfs2_stack_list);
33static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
34static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
35
36/*
37 * The stack currently in use. If not null, active_stack->sp_count > 0,
38 * the module is pinned, and the locking protocol cannot be changed.
39 */
40static struct ocfs2_stack_plugin *active_stack;
41
42static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
43{
44 struct ocfs2_stack_plugin *p;
45
46 assert_spin_locked(&ocfs2_stack_lock);
47
48 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
49 if (!strcmp(p->sp_name, name))
50 return p;
51 }
52
53 return NULL;
54}
55
56static int ocfs2_stack_driver_request(const char *stack_name,
57 const char *plugin_name)
58{
59 int rc;
60 struct ocfs2_stack_plugin *p;
61
62 spin_lock(&ocfs2_stack_lock);
63
64 /*
65 * If the stack passed by the filesystem isn't the selected one,
66 * we can't continue.
67 */
68 if (strcmp(stack_name, cluster_stack_name)) {
69 rc = -EBUSY;
70 goto out;
71 }
72
73 if (active_stack) {
74 /*
75 * If the active stack isn't the one we want, it cannot
76 * be selected right now.
77 */
78 if (!strcmp(active_stack->sp_name, plugin_name))
79 rc = 0;
80 else
81 rc = -EBUSY;
82 goto out;
83 }
84
85 p = ocfs2_stack_lookup(plugin_name);
86 if (!p || !try_module_get(p->sp_owner)) {
87 rc = -ENOENT;
88 goto out;
89 }
90
91 active_stack = p;
92 rc = 0;
93
94out:
95 /* If we found it, pin it */
96 if (!rc)
97 active_stack->sp_count++;
98
99 spin_unlock(&ocfs2_stack_lock);
100 return rc;
101}
102
103/*
104 * This function looks up the appropriate stack and makes it active. If
105 * there is no stack, it tries to load it. It will fail if the stack still
106 * cannot be found. It will also fail if a different stack is in use.
107 */
108static int ocfs2_stack_driver_get(const char *stack_name)
109{
110 int rc;
111 char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
112
113 /*
114 * Classic stack does not pass in a stack name. This is
115 * compatible with older tools as well.
116 */
117 if (!stack_name || !*stack_name)
118 stack_name = OCFS2_STACK_PLUGIN_O2CB;
119
120 if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
121 printk(KERN_ERR
122 "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
123 stack_name);
124 return -EINVAL;
125 }
126
127 /* Anything that isn't the classic stack is a user stack */
128 if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
129 plugin_name = OCFS2_STACK_PLUGIN_USER;
130
131 rc = ocfs2_stack_driver_request(stack_name, plugin_name);
132 if (rc == -ENOENT) {
133 request_module("ocfs2_stack_%s", plugin_name);
134 rc = ocfs2_stack_driver_request(stack_name, plugin_name);
135 }
136
137 if (rc == -ENOENT) {
138 printk(KERN_ERR
139 "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
140 plugin_name);
141 } else if (rc == -EBUSY) {
142 printk(KERN_ERR
143 "ocfs2: A different cluster stack is in use\n");
144 }
145
146 return rc;
147}
148
149static void ocfs2_stack_driver_put(void)
150{
151 spin_lock(&ocfs2_stack_lock);
152 BUG_ON(active_stack == NULL);
153 BUG_ON(active_stack->sp_count == 0);
154
155 active_stack->sp_count--;
156 if (!active_stack->sp_count) {
157 module_put(active_stack->sp_owner);
158 active_stack = NULL;
159 }
160 spin_unlock(&ocfs2_stack_lock);
161}
162
163int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
164{
165 int rc;
166
167 spin_lock(&ocfs2_stack_lock);
168 if (!ocfs2_stack_lookup(plugin->sp_name)) {
169 plugin->sp_count = 0;
170 plugin->sp_max_proto = locking_max_version;
171 list_add(&plugin->sp_list, &ocfs2_stack_list);
172 printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
173 plugin->sp_name);
174 rc = 0;
175 } else {
176 printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
177 plugin->sp_name);
178 rc = -EEXIST;
179 }
180 spin_unlock(&ocfs2_stack_lock);
181
182 return rc;
183}
184EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
185
186void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
187{
188 struct ocfs2_stack_plugin *p;
189
190 spin_lock(&ocfs2_stack_lock);
191 p = ocfs2_stack_lookup(plugin->sp_name);
192 if (p) {
193 BUG_ON(p != plugin);
194 BUG_ON(plugin == active_stack);
195 BUG_ON(plugin->sp_count != 0);
196 list_del_init(&plugin->sp_list);
197 printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
198 plugin->sp_name);
199 } else {
200 printk(KERN_ERR "Stack \"%s\" is not registered\n",
201 plugin->sp_name);
202 }
203 spin_unlock(&ocfs2_stack_lock);
204}
205EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
206
207void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto)
208{
209 struct ocfs2_stack_plugin *p;
210
211 spin_lock(&ocfs2_stack_lock);
212 if (memcmp(max_proto, &locking_max_version,
213 sizeof(struct ocfs2_protocol_version))) {
214 BUG_ON(locking_max_version.pv_major != 0);
215
216 locking_max_version = *max_proto;
217 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
218 p->sp_max_proto = locking_max_version;
219 }
220 }
221 spin_unlock(&ocfs2_stack_lock);
222}
223EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_max_proto_version);
224
225
226/*
227 * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take no argument
228 * for the ast and bast functions. They will pass the lksb to the ast
229 * and bast. The caller can wrap the lksb with their own structure to
230 * get more information.
231 */
232int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
233 int mode,
234 struct ocfs2_dlm_lksb *lksb,
235 u32 flags,
236 void *name,
237 unsigned int namelen)
238{
239 if (!lksb->lksb_conn)
240 lksb->lksb_conn = conn;
241 else
242 BUG_ON(lksb->lksb_conn != conn);
243 return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
244 name, namelen);
245}
246EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
247
248int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
249 struct ocfs2_dlm_lksb *lksb,
250 u32 flags)
251{
252 BUG_ON(lksb->lksb_conn == NULL);
253
254 return active_stack->sp_ops->dlm_unlock(conn, lksb, flags);
255}
256EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
257
258int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
259{
260 return active_stack->sp_ops->lock_status(lksb);
261}
262EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
263
264int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
265{
266 return active_stack->sp_ops->lvb_valid(lksb);
267}
268EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
269
270void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
271{
272 return active_stack->sp_ops->lock_lvb(lksb);
273}
274EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
275
276void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
277{
278 active_stack->sp_ops->dump_lksb(lksb);
279}
280EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
281
282int ocfs2_stack_supports_plocks(void)
283{
284 return active_stack && active_stack->sp_ops->plock;
285}
286EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
287
288/*
289 * ocfs2_plock() can only be safely called if
290 * ocfs2_stack_supports_plocks() returned true
291 */
292int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
293 struct file *file, int cmd, struct file_lock *fl)
294{
295 WARN_ON_ONCE(active_stack->sp_ops->plock == NULL);
296 if (active_stack->sp_ops->plock)
297 return active_stack->sp_ops->plock(conn, ino, file, cmd, fl);
298 return -EOPNOTSUPP;
299}
300EXPORT_SYMBOL_GPL(ocfs2_plock);
301
302int ocfs2_cluster_connect(const char *stack_name,
303 const char *cluster_name,
304 int cluster_name_len,
305 const char *group,
306 int grouplen,
307 struct ocfs2_locking_protocol *lproto,
308 void (*recovery_handler)(int node_num,
309 void *recovery_data),
310 void *recovery_data,
311 struct ocfs2_cluster_connection **conn)
312{
313 int rc = 0;
314 struct ocfs2_cluster_connection *new_conn;
315
316 BUG_ON(group == NULL);
317 BUG_ON(conn == NULL);
318 BUG_ON(recovery_handler == NULL);
319
320 if (grouplen > GROUP_NAME_MAX) {
321 rc = -EINVAL;
322 goto out;
323 }
324
325 if (memcmp(&lproto->lp_max_version, &locking_max_version,
326 sizeof(struct ocfs2_protocol_version))) {
327 rc = -EINVAL;
328 goto out;
329 }
330
331 new_conn = kzalloc_obj(struct ocfs2_cluster_connection);
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
363out_free:
364 if (rc)
365 kfree(new_conn);
366
367out:
368 return rc;
369}
370EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
371
372/* The caller will ensure all nodes have the same cluster stack */
373int 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}
389EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
390
391/* If hangup_pending is 0, the stack driver will be dropped */
392int 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}
410EXPORT_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 */
416static 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 */
448void 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}
458EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
459
460int 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}
465EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
466
467
468/*
469 * Sysfs bits
470 */
471
472static 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
488static struct kobj_attribute ocfs2_attr_max_locking_protocol =
489 __ATTR(max_locking_protocol, S_IRUGO,
490 ocfs2_max_locking_protocol_show, NULL);
491
492static 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
516static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
517 __ATTR(loaded_cluster_plugins, S_IRUGO,
518 ocfs2_loaded_cluster_plugins_show, NULL);
519
520static 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
538static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
539 __ATTR(active_cluster_plugin, S_IRUGO,
540 ocfs2_active_cluster_plugin_show, NULL);
541
542static 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
554static 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
587static 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
594static 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
601static struct kobj_attribute ocfs2_attr_dlm_recover_support =
602 __ATTR(dlm_recover_callback_support, S_IRUGO,
603 ocfs2_dlm_recover_show, NULL);
604
605static 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
614static const struct attribute_group ocfs2_attr_group = {
615 .attrs = ocfs2_attrs,
616};
617
618struct kset *ocfs2_kset;
619EXPORT_SYMBOL_GPL(ocfs2_kset);
620
621static void ocfs2_sysfs_exit(void)
622{
623 kset_unregister(ocfs2_kset);
624}
625
626static 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
640error:
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
653static const 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
663static struct ctl_table_header *ocfs2_table_header;
664
665/*
666 * Initialization
667 */
668
669static int __init ocfs2_stack_glue_init(void)
670{
671 int ret;
672
673 strscpy(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
689static 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 unregister_sysctl_table(ocfs2_table_header);
695}
696
697MODULE_AUTHOR("Oracle");
698MODULE_DESCRIPTION("ocfs2 cluster stack glue layer");
699MODULE_LICENSE("GPL");
700module_init(ocfs2_stack_glue_init);
701module_exit(ocfs2_stack_glue_exit);