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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
39static struct ocfs2_protocol_version locking_max_version;
40static DEFINE_SPINLOCK(ocfs2_stack_lock);
41static LIST_HEAD(ocfs2_stack_list);
42static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
43static 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 */
49static struct ocfs2_stack_plugin *active_stack;
50
51static 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
65static 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
103out:
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 */
117static 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
158static 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
172int 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}
193EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
194
195void 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}
214EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
215
216void 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}
232EXPORT_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 */
241int 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}
255EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
256
257int 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}
265EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
266
267int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
268{
269 return active_stack->sp_ops->lock_status(lksb);
270}
271EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
272
273int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
274{
275 return active_stack->sp_ops->lvb_valid(lksb);
276}
277EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
278
279void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
280{
281 return active_stack->sp_ops->lock_lvb(lksb);
282}
283EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
284
285void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
286{
287 active_stack->sp_ops->dump_lksb(lksb);
288}
289EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
290
291int ocfs2_stack_supports_plocks(void)
292{
293 return active_stack && active_stack->sp_ops->plock;
294}
295EXPORT_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 */
301int 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}
309EXPORT_SYMBOL_GPL(ocfs2_plock);
310
311int 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
373out_free:
374 if (rc)
375 kfree(new_conn);
376
377out:
378 return rc;
379}
380EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
381
382/* The caller will ensure all nodes have the same cluster stack */
383int 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}
399EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
400
401/* If hangup_pending is 0, the stack driver will be dropped */
402int 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}
420EXPORT_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 */
426static 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 */
458void 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}
468EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
469
470int 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}
475EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
476
477
478/*
479 * Sysfs bits
480 */
481
482static 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
498static struct kobj_attribute ocfs2_attr_max_locking_protocol =
499 __ATTR(max_locking_protocol, S_IRUGO,
500 ocfs2_max_locking_protocol_show, NULL);
501
502static 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 < 0) {
514 total = ret;
515 break;
516 }
517 if (ret == remain) {
518 /* snprintf() didn't fit */
519 total = -E2BIG;
520 break;
521 }
522 total += ret;
523 remain -= ret;
524 }
525 spin_unlock(&ocfs2_stack_lock);
526
527 return total;
528}
529
530static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
531 __ATTR(loaded_cluster_plugins, S_IRUGO,
532 ocfs2_loaded_cluster_plugins_show, NULL);
533
534static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
535 struct kobj_attribute *attr,
536 char *buf)
537{
538 ssize_t ret = 0;
539
540 spin_lock(&ocfs2_stack_lock);
541 if (active_stack) {
542 ret = snprintf(buf, PAGE_SIZE, "%s\n",
543 active_stack->sp_name);
544 if (ret == PAGE_SIZE)
545 ret = -E2BIG;
546 }
547 spin_unlock(&ocfs2_stack_lock);
548
549 return ret;
550}
551
552static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
553 __ATTR(active_cluster_plugin, S_IRUGO,
554 ocfs2_active_cluster_plugin_show, NULL);
555
556static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
557 struct kobj_attribute *attr,
558 char *buf)
559{
560 ssize_t ret;
561 spin_lock(&ocfs2_stack_lock);
562 ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
563 spin_unlock(&ocfs2_stack_lock);
564
565 return ret;
566}
567
568static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
569 struct kobj_attribute *attr,
570 const char *buf, size_t count)
571{
572 size_t len = count;
573 ssize_t ret;
574
575 if (len == 0)
576 return len;
577
578 if (buf[len - 1] == '\n')
579 len--;
580
581 if ((len != OCFS2_STACK_LABEL_LEN) ||
582 (strnlen(buf, len) != len))
583 return -EINVAL;
584
585 spin_lock(&ocfs2_stack_lock);
586 if (active_stack) {
587 if (!strncmp(buf, cluster_stack_name, len))
588 ret = count;
589 else
590 ret = -EBUSY;
591 } else {
592 memcpy(cluster_stack_name, buf, len);
593 ret = count;
594 }
595 spin_unlock(&ocfs2_stack_lock);
596
597 return ret;
598}
599
600
601static struct kobj_attribute ocfs2_attr_cluster_stack =
602 __ATTR(cluster_stack, S_IRUGO | S_IWUSR,
603 ocfs2_cluster_stack_show,
604 ocfs2_cluster_stack_store);
605
606
607
608static ssize_t ocfs2_dlm_recover_show(struct kobject *kobj,
609 struct kobj_attribute *attr,
610 char *buf)
611{
612 return snprintf(buf, PAGE_SIZE, "1\n");
613}
614
615static struct kobj_attribute ocfs2_attr_dlm_recover_support =
616 __ATTR(dlm_recover_callback_support, S_IRUGO,
617 ocfs2_dlm_recover_show, NULL);
618
619static struct attribute *ocfs2_attrs[] = {
620 &ocfs2_attr_max_locking_protocol.attr,
621 &ocfs2_attr_loaded_cluster_plugins.attr,
622 &ocfs2_attr_active_cluster_plugin.attr,
623 &ocfs2_attr_cluster_stack.attr,
624 &ocfs2_attr_dlm_recover_support.attr,
625 NULL,
626};
627
628static struct attribute_group ocfs2_attr_group = {
629 .attrs = ocfs2_attrs,
630};
631
632static struct kset *ocfs2_kset;
633
634static void ocfs2_sysfs_exit(void)
635{
636 kset_unregister(ocfs2_kset);
637}
638
639static int ocfs2_sysfs_init(void)
640{
641 int ret;
642
643 ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
644 if (!ocfs2_kset)
645 return -ENOMEM;
646
647 ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
648 if (ret)
649 goto error;
650
651 return 0;
652
653error:
654 kset_unregister(ocfs2_kset);
655 return ret;
656}
657
658/*
659 * Sysctl bits
660 *
661 * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path. The 'nm' doesn't
662 * make as much sense in a multiple cluster stack world, but it's safer
663 * and easier to preserve the name.
664 */
665
666#define FS_OCFS2_NM 1
667
668static struct ctl_table ocfs2_nm_table[] = {
669 {
670 .procname = "hb_ctl_path",
671 .data = ocfs2_hb_ctl_path,
672 .maxlen = OCFS2_MAX_HB_CTL_PATH,
673 .mode = 0644,
674 .proc_handler = proc_dostring,
675 },
676 { }
677};
678
679static struct ctl_table ocfs2_mod_table[] = {
680 {
681 .procname = "nm",
682 .data = NULL,
683 .maxlen = 0,
684 .mode = 0555,
685 .child = ocfs2_nm_table
686 },
687 { }
688};
689
690static struct ctl_table ocfs2_kern_table[] = {
691 {
692 .procname = "ocfs2",
693 .data = NULL,
694 .maxlen = 0,
695 .mode = 0555,
696 .child = ocfs2_mod_table
697 },
698 { }
699};
700
701static struct ctl_table ocfs2_root_table[] = {
702 {
703 .procname = "fs",
704 .data = NULL,
705 .maxlen = 0,
706 .mode = 0555,
707 .child = ocfs2_kern_table
708 },
709 { }
710};
711
712static struct ctl_table_header *ocfs2_table_header = NULL;
713
714
715/*
716 * Initialization
717 */
718
719static int __init ocfs2_stack_glue_init(void)
720{
721 strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
722
723 ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
724 if (!ocfs2_table_header) {
725 printk(KERN_ERR
726 "ocfs2 stack glue: unable to register sysctl\n");
727 return -ENOMEM; /* or something. */
728 }
729
730 return ocfs2_sysfs_init();
731}
732
733static void __exit ocfs2_stack_glue_exit(void)
734{
735 memset(&locking_max_version, 0,
736 sizeof(struct ocfs2_protocol_version));
737 locking_max_version.pv_major = 0;
738 locking_max_version.pv_minor = 0;
739 ocfs2_sysfs_exit();
740 if (ocfs2_table_header)
741 unregister_sysctl_table(ocfs2_table_header);
742}
743
744MODULE_AUTHOR("Oracle");
745MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
746MODULE_LICENSE("GPL");
747module_init(ocfs2_stack_glue_init);
748module_exit(ocfs2_stack_glue_exit);
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
29static struct ocfs2_protocol_version locking_max_version;
30static DEFINE_SPINLOCK(ocfs2_stack_lock);
31static LIST_HEAD(ocfs2_stack_list);
32static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
33static 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 */
39static struct ocfs2_stack_plugin *active_stack;
40
41static 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
55static 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
93out:
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 */
107static 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
148static 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
162int 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}
183EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
184
185void 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}
204EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
205
206void 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}
222EXPORT_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 */
231int 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}
245EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
246
247int 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}
255EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
256
257int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb)
258{
259 return active_stack->sp_ops->lock_status(lksb);
260}
261EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
262
263int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb)
264{
265 return active_stack->sp_ops->lvb_valid(lksb);
266}
267EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb_valid);
268
269void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb)
270{
271 return active_stack->sp_ops->lock_lvb(lksb);
272}
273EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
274
275void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb)
276{
277 active_stack->sp_ops->dump_lksb(lksb);
278}
279EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
280
281int ocfs2_stack_supports_plocks(void)
282{
283 return active_stack && active_stack->sp_ops->plock;
284}
285EXPORT_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 */
291int 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}
299EXPORT_SYMBOL_GPL(ocfs2_plock);
300
301int 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
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 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
664static struct ctl_table_header *ocfs2_table_header;
665
666/*
667 * Initialization
668 */
669
670static int __init ocfs2_stack_glue_init(void)
671{
672 int ret;
673
674 strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
675
676 ocfs2_table_header = register_sysctl("fs/ocfs2/nm", ocfs2_nm_table);
677 if (!ocfs2_table_header) {
678 printk(KERN_ERR
679 "ocfs2 stack glue: unable to register sysctl\n");
680 return -ENOMEM; /* or something. */
681 }
682
683 ret = ocfs2_sysfs_init();
684 if (ret)
685 unregister_sysctl_table(ocfs2_table_header);
686
687 return ret;
688}
689
690static void __exit ocfs2_stack_glue_exit(void)
691{
692 memset(&locking_max_version, 0,
693 sizeof(struct ocfs2_protocol_version));
694 ocfs2_sysfs_exit();
695 if (ocfs2_table_header)
696 unregister_sysctl_table(ocfs2_table_header);
697}
698
699MODULE_AUTHOR("Oracle");
700MODULE_DESCRIPTION("ocfs2 cluster stack glue layer");
701MODULE_LICENSE("GPL");
702module_init(ocfs2_stack_glue_init);
703module_exit(ocfs2_stack_glue_exit);