1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
6 * Code which implements an OCFS2 specific interface to underlying
9 * Copyright (C) 2007 Oracle. All rights reserved.
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.
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.
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>
27 #include <linux/kobject.h>
28 #include <linux/sysfs.h>
29 #include <linux/sysctl.h>
33 #include "stackglue.h"
35 #define OCFS2_STACK_PLUGIN_O2CB "o2cb"
36 #define OCFS2_STACK_PLUGIN_USER "user"
37 #define OCFS2_MAX_HB_CTL_PATH 256
39 static struct ocfs2_locking_protocol *lproto;
40 static DEFINE_SPINLOCK(ocfs2_stack_lock);
41 static LIST_HEAD(ocfs2_stack_list);
42 static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
43 static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
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.
49 static struct ocfs2_stack_plugin *active_stack;
51 static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
53 struct ocfs2_stack_plugin *p;
55 assert_spin_locked(&ocfs2_stack_lock);
57 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
58 if (!strcmp(p->sp_name, name))
65 static int ocfs2_stack_driver_request(const char *stack_name,
66 const char *plugin_name)
69 struct ocfs2_stack_plugin *p;
71 spin_lock(&ocfs2_stack_lock);
74 * If the stack passed by the filesystem isn't the selected one,
77 if (strcmp(stack_name, cluster_stack_name)) {
84 * If the active stack isn't the one we want, it cannot
85 * be selected right now.
87 if (!strcmp(active_stack->sp_name, plugin_name))
94 p = ocfs2_stack_lookup(plugin_name);
95 if (!p || !try_module_get(p->sp_owner)) {
104 /* If we found it, pin it */
106 active_stack->sp_count++;
108 spin_unlock(&ocfs2_stack_lock);
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.
117 static int ocfs2_stack_driver_get(const char *stack_name)
120 char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
123 * Classic stack does not pass in a stack name. This is
124 * compatible with older tools as well.
126 if (!stack_name || !*stack_name)
127 stack_name = OCFS2_STACK_PLUGIN_O2CB;
129 if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
131 "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
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;
140 rc = ocfs2_stack_driver_request(stack_name, plugin_name);
142 request_module("ocfs2_stack_%s", plugin_name);
143 rc = ocfs2_stack_driver_request(stack_name, plugin_name);
148 "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
150 } else if (rc == -EBUSY) {
152 "ocfs2: A different cluster stack is in use\n");
158 static void ocfs2_stack_driver_put(void)
160 spin_lock(&ocfs2_stack_lock);
161 BUG_ON(active_stack == NULL);
162 BUG_ON(active_stack->sp_count == 0);
164 active_stack->sp_count--;
165 if (!active_stack->sp_count) {
166 module_put(active_stack->sp_owner);
169 spin_unlock(&ocfs2_stack_lock);
172 int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
176 spin_lock(&ocfs2_stack_lock);
177 if (!ocfs2_stack_lookup(plugin->sp_name)) {
178 plugin->sp_count = 0;
179 plugin->sp_proto = lproto;
180 list_add(&plugin->sp_list, &ocfs2_stack_list);
181 printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
185 printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
189 spin_unlock(&ocfs2_stack_lock);
193 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
195 void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
197 struct ocfs2_stack_plugin *p;
199 spin_lock(&ocfs2_stack_lock);
200 p = ocfs2_stack_lookup(plugin->sp_name);
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",
209 printk(KERN_ERR "Stack \"%s\" is not registered\n",
212 spin_unlock(&ocfs2_stack_lock);
214 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
216 void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto)
218 struct ocfs2_stack_plugin *p;
220 BUG_ON(proto == NULL);
222 spin_lock(&ocfs2_stack_lock);
223 BUG_ON(active_stack != NULL);
226 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
227 p->sp_proto = lproto;
230 spin_unlock(&ocfs2_stack_lock);
232 EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_locking_protocol);
236 * The ocfs2_dlm_lock() and ocfs2_dlm_unlock() functions take
237 * "struct ocfs2_lock_res *astarg" instead of "void *astarg" because the
238 * underlying stack plugins need to pilfer the lksb off of the lock_res.
239 * If some other structure needs to be passed as an astarg, the plugins
240 * will need to be given a different avenue to the lksb.
242 int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
244 union ocfs2_dlm_lksb *lksb,
247 unsigned int namelen,
248 struct ocfs2_lock_res *astarg)
250 BUG_ON(lproto == NULL);
252 return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
253 name, namelen, astarg);
255 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
257 int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
258 union ocfs2_dlm_lksb *lksb,
260 struct ocfs2_lock_res *astarg)
262 BUG_ON(lproto == NULL);
264 return active_stack->sp_ops->dlm_unlock(conn, lksb, flags, astarg);
266 EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
268 int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
270 return active_stack->sp_ops->lock_status(lksb);
272 EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
275 * Why don't we cast to ocfs2_meta_lvb? The "clean" answer is that we
276 * don't cast at the glue level. The real answer is that the header
277 * ordering is nigh impossible.
279 void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb)
281 return active_stack->sp_ops->lock_lvb(lksb);
283 EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
285 void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
287 active_stack->sp_ops->dump_lksb(lksb);
289 EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
291 int ocfs2_stack_supports_plocks(void)
293 return active_stack && active_stack->sp_ops->plock;
295 EXPORT_SYMBOL_GPL(ocfs2_stack_supports_plocks);
298 * ocfs2_plock() can only be safely called if
299 * ocfs2_stack_supports_plocks() returned true
301 int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
302 struct file *file, int cmd, struct file_lock *fl)
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);
309 EXPORT_SYMBOL_GPL(ocfs2_plock);
311 int ocfs2_cluster_connect(const char *stack_name,
314 void (*recovery_handler)(int node_num,
315 void *recovery_data),
317 struct ocfs2_cluster_connection **conn)
320 struct ocfs2_cluster_connection *new_conn;
322 BUG_ON(group == NULL);
323 BUG_ON(conn == NULL);
324 BUG_ON(recovery_handler == NULL);
326 if (grouplen > GROUP_NAME_MAX) {
331 new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
338 memcpy(new_conn->cc_name, group, grouplen);
339 new_conn->cc_namelen = grouplen;
340 new_conn->cc_recovery_handler = recovery_handler;
341 new_conn->cc_recovery_data = recovery_data;
343 /* Start the new connection at our maximum compatibility level */
344 new_conn->cc_version = lproto->lp_max_version;
346 /* This will pin the stack driver if successful */
347 rc = ocfs2_stack_driver_get(stack_name);
351 rc = active_stack->sp_ops->connect(new_conn);
353 ocfs2_stack_driver_put();
366 EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
368 /* If hangup_pending is 0, the stack driver will be dropped */
369 int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
374 BUG_ON(conn == NULL);
376 ret = active_stack->sp_ops->disconnect(conn);
378 /* XXX Should we free it anyway? */
382 ocfs2_stack_driver_put();
387 EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
390 * Leave the group for this filesystem. This is executed by a userspace
391 * program (stored in ocfs2_hb_ctl_path).
393 static void ocfs2_leave_group(const char *group)
396 char *argv[5], *envp[3];
398 argv[0] = ocfs2_hb_ctl_path;
401 argv[3] = (char *)group;
404 /* minimal command environment taken from cpu_run_sbin_hotplug */
406 envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
409 ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
412 "ocfs2: Error %d running user helper "
414 ret, argv[0], argv[1], argv[2], argv[3]);
419 * Hangup is a required post-umount. ocfs2-tools software expects the
420 * filesystem to call "ocfs2_hb_ctl" during unmount. This happens
421 * regardless of whether the DLM got started, so we can't do it
422 * in ocfs2_cluster_disconnect(). The ocfs2_leave_group() function does
425 void ocfs2_cluster_hangup(const char *group, int grouplen)
427 BUG_ON(group == NULL);
428 BUG_ON(group[grouplen] != '\0');
430 ocfs2_leave_group(group);
432 /* cluster_disconnect() was called with hangup_pending==1 */
433 ocfs2_stack_driver_put();
435 EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
437 int ocfs2_cluster_this_node(unsigned int *node)
439 return active_stack->sp_ops->this_node(node);
441 EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
448 static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
449 struct kobj_attribute *attr,
454 spin_lock(&ocfs2_stack_lock);
456 ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
457 lproto->lp_max_version.pv_major,
458 lproto->lp_max_version.pv_minor);
459 spin_unlock(&ocfs2_stack_lock);
464 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
465 __ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
466 ocfs2_max_locking_protocol_show, NULL);
468 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
469 struct kobj_attribute *attr,
472 ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
473 struct ocfs2_stack_plugin *p;
475 spin_lock(&ocfs2_stack_lock);
476 list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
477 ret = snprintf(buf, remain, "%s\n",
484 /* snprintf() didn't fit */
491 spin_unlock(&ocfs2_stack_lock);
496 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
497 __ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
498 ocfs2_loaded_cluster_plugins_show, NULL);
500 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
501 struct kobj_attribute *attr,
506 spin_lock(&ocfs2_stack_lock);
508 ret = snprintf(buf, PAGE_SIZE, "%s\n",
509 active_stack->sp_name);
510 if (ret == PAGE_SIZE)
513 spin_unlock(&ocfs2_stack_lock);
518 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
519 __ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
520 ocfs2_active_cluster_plugin_show, NULL);
522 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
523 struct kobj_attribute *attr,
527 spin_lock(&ocfs2_stack_lock);
528 ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
529 spin_unlock(&ocfs2_stack_lock);
534 static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
535 struct kobj_attribute *attr,
536 const char *buf, size_t count)
544 if (buf[len - 1] == '\n')
547 if ((len != OCFS2_STACK_LABEL_LEN) ||
548 (strnlen(buf, len) != len))
551 spin_lock(&ocfs2_stack_lock);
553 if (!strncmp(buf, cluster_stack_name, len))
558 memcpy(cluster_stack_name, buf, len);
561 spin_unlock(&ocfs2_stack_lock);
567 static struct kobj_attribute ocfs2_attr_cluster_stack =
568 __ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
569 ocfs2_cluster_stack_show,
570 ocfs2_cluster_stack_store);
572 static struct attribute *ocfs2_attrs[] = {
573 &ocfs2_attr_max_locking_protocol.attr,
574 &ocfs2_attr_loaded_cluster_plugins.attr,
575 &ocfs2_attr_active_cluster_plugin.attr,
576 &ocfs2_attr_cluster_stack.attr,
580 static struct attribute_group ocfs2_attr_group = {
581 .attrs = ocfs2_attrs,
584 static struct kset *ocfs2_kset;
586 static void ocfs2_sysfs_exit(void)
588 kset_unregister(ocfs2_kset);
591 static int ocfs2_sysfs_init(void)
595 ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
599 ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
606 kset_unregister(ocfs2_kset);
613 * The sysctl lives at /proc/sys/fs/ocfs2/nm/hb_ctl_path. The 'nm' doesn't
614 * make as much sense in a multiple cluster stack world, but it's safer
615 * and easier to preserve the name.
618 #define FS_OCFS2_NM 1
620 static ctl_table ocfs2_nm_table[] = {
623 .procname = "hb_ctl_path",
624 .data = ocfs2_hb_ctl_path,
625 .maxlen = OCFS2_MAX_HB_CTL_PATH,
627 .proc_handler = &proc_dostring,
628 .strategy = &sysctl_string,
633 static ctl_table ocfs2_mod_table[] = {
635 .ctl_name = FS_OCFS2_NM,
640 .child = ocfs2_nm_table
645 static ctl_table ocfs2_kern_table[] = {
647 .ctl_name = FS_OCFS2,
652 .child = ocfs2_mod_table
657 static ctl_table ocfs2_root_table[] = {
664 .child = ocfs2_kern_table
669 static struct ctl_table_header *ocfs2_table_header = NULL;
676 static int __init ocfs2_stack_glue_init(void)
678 strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
680 ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
681 if (!ocfs2_table_header) {
683 "ocfs2 stack glue: unable to register sysctl\n");
684 return -ENOMEM; /* or something. */
687 return ocfs2_sysfs_init();
690 static void __exit ocfs2_stack_glue_exit(void)
694 if (ocfs2_table_header)
695 unregister_sysctl_table(ocfs2_table_header);
698 MODULE_AUTHOR("Oracle");
699 MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
700 MODULE_LICENSE("GPL");
701 module_init(ocfs2_stack_glue_init);
702 module_exit(ocfs2_stack_glue_exit);