[mirror_ubuntu-artful-kernel.git] / fs / ocfs2 / stackglue.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * stackglue.c
 *
 * Code which implements an OCFS2 specific interface to underlying
 * cluster stacks.
 *
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/fs.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>

#include "ocfs2_fs.h"

#include "stackglue.h"

#define OCFS2_STACK_PLUGIN_O2CB		"o2cb"
#define OCFS2_STACK_PLUGIN_USER		"user"

static struct ocfs2_locking_protocol *lproto;
static DEFINE_SPINLOCK(ocfs2_stack_lock);
static LIST_HEAD(ocfs2_stack_list);
static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];

/*
 * The stack currently in use.  If not null, active_stack->sp_count > 0,
 * the module is pinned, and the locking protocol cannot be changed.
 */
static struct ocfs2_stack_plugin *active_stack;

static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name)
{
	struct ocfs2_stack_plugin *p;

	assert_spin_locked(&ocfs2_stack_lock);

	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
		if (!strcmp(p->sp_name, name))
			return p;
	}

	return NULL;
}

static int ocfs2_stack_driver_request(const char *stack_name,
				      const char *plugin_name)
{
	int rc;
	struct ocfs2_stack_plugin *p;

	spin_lock(&ocfs2_stack_lock);

	/*
	 * If the stack passed by the filesystem isn't the selected one,
	 * we can't continue.
	 */
	if (strcmp(stack_name, cluster_stack_name)) {
		rc = -EBUSY;
		goto out;
	}

	if (active_stack) {
		/*
		 * If the active stack isn't the one we want, it cannot
		 * be selected right now.
		 */
		if (!strcmp(active_stack->sp_name, plugin_name))
			rc = 0;
		else
			rc = -EBUSY;
		goto out;
	}

	p = ocfs2_stack_lookup(plugin_name);
	if (!p || !try_module_get(p->sp_owner)) {
		rc = -ENOENT;
		goto out;
	}

	/* Ok, the stack is pinned */
	p->sp_count++;
	active_stack = p;

	rc = 0;

out:
	spin_unlock(&ocfs2_stack_lock);
	return rc;
}

/*
 * This function looks up the appropriate stack and makes it active.  If
 * there is no stack, it tries to load it.  It will fail if the stack still
 * cannot be found.  It will also fail if a different stack is in use.
 */
static int ocfs2_stack_driver_get(const char *stack_name)
{
	int rc;
	char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;

	/*
	 * Classic stack does not pass in a stack name.  This is
	 * compatible with older tools as well.
	 */
	if (!stack_name || !*stack_name)
		stack_name = OCFS2_STACK_PLUGIN_O2CB;

	if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
		printk(KERN_ERR
		       "ocfs2 passed an invalid cluster stack label: \"%s\"\n",
		       stack_name);
		return -EINVAL;
	}

	/* Anything that isn't the classic stack is a user stack */
	if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
		plugin_name = OCFS2_STACK_PLUGIN_USER;

	rc = ocfs2_stack_driver_request(stack_name, plugin_name);
	if (rc == -ENOENT) {
		request_module("ocfs2_stack_%s", plugin_name);
		rc = ocfs2_stack_driver_request(stack_name, plugin_name);
	}

	if (rc == -ENOENT) {
		printk(KERN_ERR
		       "ocfs2: Cluster stack driver \"%s\" cannot be found\n",
		       plugin_name);
	} else if (rc == -EBUSY) {
		printk(KERN_ERR
		       "ocfs2: A different cluster stack is in use\n");
	}

	return rc;
}

static void ocfs2_stack_driver_put(void)
{
	spin_lock(&ocfs2_stack_lock);
	BUG_ON(active_stack == NULL);
	BUG_ON(active_stack->sp_count == 0);

	active_stack->sp_count--;
	if (!active_stack->sp_count) {
		module_put(active_stack->sp_owner);
		active_stack = NULL;
	}
	spin_unlock(&ocfs2_stack_lock);
}

int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
{
	int rc;

	spin_lock(&ocfs2_stack_lock);
	if (!ocfs2_stack_lookup(plugin->sp_name)) {
		plugin->sp_count = 0;
		plugin->sp_proto = lproto;
		list_add(&plugin->sp_list, &ocfs2_stack_list);
		printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
		       plugin->sp_name);
		rc = 0;
	} else {
		printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
		       plugin->sp_name);
		rc = -EEXIST;
	}
	spin_unlock(&ocfs2_stack_lock);

	return rc;
}
EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);

void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
{
	struct ocfs2_stack_plugin *p;

	spin_lock(&ocfs2_stack_lock);
	p = ocfs2_stack_lookup(plugin->sp_name);
	if (p) {
		BUG_ON(p != plugin);
		BUG_ON(plugin == active_stack);
		BUG_ON(plugin->sp_count != 0);
		list_del_init(&plugin->sp_list);
		printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
		       plugin->sp_name);
	} else {
		printk(KERN_ERR "Stack \"%s\" is not registered\n",
		       plugin->sp_name);
	}
	spin_unlock(&ocfs2_stack_lock);
}
EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);

void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto)
{
	struct ocfs2_stack_plugin *p;

	BUG_ON(proto == NULL);

	spin_lock(&ocfs2_stack_lock);
	BUG_ON(active_stack != NULL);

	lproto = proto;
	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
		p->sp_proto = lproto;
	}

	spin_unlock(&ocfs2_stack_lock);
}
EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_locking_protocol);


int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
		   int mode,
		   union ocfs2_dlm_lksb *lksb,
		   u32 flags,
		   void *name,
		   unsigned int namelen,
		   void *astarg)
{
	BUG_ON(lproto == NULL);

	return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
					      name, namelen, astarg);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);

int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
		     union ocfs2_dlm_lksb *lksb,
		     u32 flags,
		     void *astarg)
{
	BUG_ON(lproto == NULL);

	return active_stack->sp_ops->dlm_unlock(conn, lksb, flags, astarg);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);

int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
{
	return active_stack->sp_ops->lock_status(lksb);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);

/*
 * Why don't we cast to ocfs2_meta_lvb?  The "clean" answer is that we
 * don't cast at the glue level.  The real answer is that the header
 * ordering is nigh impossible.
 */
void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb)
{
	return active_stack->sp_ops->lock_lvb(lksb);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);

void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
{
	active_stack->sp_ops->dump_lksb(lksb);
}
EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);

int ocfs2_cluster_connect(const char *stack_name,
			  const char *group,
			  int grouplen,
			  void (*recovery_handler)(int node_num,
						   void *recovery_data),
			  void *recovery_data,
			  struct ocfs2_cluster_connection **conn)
{
	int rc = 0;
	struct ocfs2_cluster_connection *new_conn;

	BUG_ON(group == NULL);
	BUG_ON(conn == NULL);
	BUG_ON(recovery_handler == NULL);

	if (grouplen > GROUP_NAME_MAX) {
		rc = -EINVAL;
		goto out;
	}

	new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
			   GFP_KERNEL);
	if (!new_conn) {
		rc = -ENOMEM;
		goto out;
	}

	memcpy(new_conn->cc_name, group, grouplen);
	new_conn->cc_namelen = grouplen;
	new_conn->cc_recovery_handler = recovery_handler;
	new_conn->cc_recovery_data = recovery_data;

	/* Start the new connection at our maximum compatibility level */
	new_conn->cc_version = lproto->lp_max_version;

	/* This will pin the stack driver if successful */
	rc = ocfs2_stack_driver_get(stack_name);
	if (rc)
		goto out_free;

	rc = active_stack->sp_ops->connect(new_conn);
	if (rc) {
		ocfs2_stack_driver_put();
		goto out_free;
	}

	*conn = new_conn;

out_free:
	if (rc)
		kfree(new_conn);

out:
	return rc;
}
EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);

/* If hangup_pending is 0, the stack driver will be dropped */
int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
			     int hangup_pending)
{
	int ret;

	BUG_ON(conn == NULL);

	ret = active_stack->sp_ops->disconnect(conn, hangup_pending);

	/* XXX Should we free it anyway? */
	if (!ret) {
		kfree(conn);
		if (!hangup_pending)
			ocfs2_stack_driver_put();
	}

	return ret;
}
EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);

void ocfs2_cluster_hangup(const char *group, int grouplen)
{
	BUG_ON(group == NULL);
	BUG_ON(group[grouplen] != '\0');

	active_stack->sp_ops->hangup(group, grouplen);

	/* cluster_disconnect() was called with hangup_pending==1 */
	ocfs2_stack_driver_put();
}
EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);

int ocfs2_cluster_this_node(unsigned int *node)
{
	return active_stack->sp_ops->this_node(node);
}
EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);


/*
 * Sysfs bits
 */

static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
					       struct kobj_attribute *attr,
					       char *buf)
{
	ssize_t ret = 0;

	spin_lock(&ocfs2_stack_lock);
	if (lproto)
		ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
			       lproto->lp_max_version.pv_major,
			       lproto->lp_max_version.pv_minor);
	spin_unlock(&ocfs2_stack_lock);

	return ret;
}

static struct kobj_attribute ocfs2_attr_max_locking_protocol =
	__ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
	       ocfs2_max_locking_protocol_show, NULL);

static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
						 struct kobj_attribute *attr,
						 char *buf)
{
	ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
	struct ocfs2_stack_plugin *p;

	spin_lock(&ocfs2_stack_lock);
	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
		ret = snprintf(buf, remain, "%s\n",
			       p->sp_name);
		if (ret < 0) {
			total = ret;
			break;
		}
		if (ret == remain) {
			/* snprintf() didn't fit */
			total = -E2BIG;
			break;
		}
		total += ret;
		remain -= ret;
	}
	spin_unlock(&ocfs2_stack_lock);

	return total;
}

static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
	__ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
	       ocfs2_loaded_cluster_plugins_show, NULL);

static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
						struct kobj_attribute *attr,
						char *buf)
{
	ssize_t ret = 0;

	spin_lock(&ocfs2_stack_lock);
	if (active_stack) {
		ret = snprintf(buf, PAGE_SIZE, "%s\n",
			       active_stack->sp_name);
		if (ret == PAGE_SIZE)
			ret = -E2BIG;
	}
	spin_unlock(&ocfs2_stack_lock);

	return ret;
}

static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
	__ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
	       ocfs2_active_cluster_plugin_show, NULL);

static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
					struct kobj_attribute *attr,
					char *buf)
{
	ssize_t ret;
	spin_lock(&ocfs2_stack_lock);
	ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
	spin_unlock(&ocfs2_stack_lock);

	return ret;
}

static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
					 struct kobj_attribute *attr,
					 const char *buf, size_t count)
{
	size_t len = count;
	ssize_t ret;

	if (len == 0)
		return len;

	if (buf[len - 1] == '\n')
		len--;

	if ((len != OCFS2_STACK_LABEL_LEN) ||
	    (strnlen(buf, len) != len))
		return -EINVAL;

	spin_lock(&ocfs2_stack_lock);
	if (active_stack) {
		if (!strncmp(buf, cluster_stack_name, len))
			ret = count;
		else
			ret = -EBUSY;
	} else {
		memcpy(cluster_stack_name, buf, len);
		ret = count;
	}
	spin_unlock(&ocfs2_stack_lock);

	return ret;
}


static struct kobj_attribute ocfs2_attr_cluster_stack =
	__ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
	       ocfs2_cluster_stack_show,
	       ocfs2_cluster_stack_store);

static struct attribute *ocfs2_attrs[] = {
	&ocfs2_attr_max_locking_protocol.attr,
	&ocfs2_attr_loaded_cluster_plugins.attr,
	&ocfs2_attr_active_cluster_plugin.attr,
	&ocfs2_attr_cluster_stack.attr,
	NULL,
};

static struct attribute_group ocfs2_attr_group = {
	.attrs = ocfs2_attrs,
};

static struct kset *ocfs2_kset;

static void ocfs2_sysfs_exit(void)
{
	kset_unregister(ocfs2_kset);
}

static int ocfs2_sysfs_init(void)
{
	int ret;

	ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
	if (!ocfs2_kset)
		return -ENOMEM;

	ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
	if (ret)
		goto error;

	return 0;

error:
	kset_unregister(ocfs2_kset);
	return ret;
}

static int __init ocfs2_stack_glue_init(void)
{
	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);

	return ocfs2_sysfs_init();
}

static void __exit ocfs2_stack_glue_exit(void)
{
	lproto = NULL;
	ocfs2_sysfs_exit();
}

MODULE_AUTHOR("Oracle");
MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
MODULE_LICENSE("GPL");
module_init(ocfs2_stack_glue_init);
module_exit(ocfs2_stack_glue_exit);
Commit	Line	Data
24ef1815 JB	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 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
286eaa95 JB	21	#include <linux/list.h>
	22	#include <linux/spinlock.h>
	23	#include <linux/module.h>
4670c46d	24	#include <linux/slab.h>
6953b4c0	25	#include <linux/kmod.h>
74ae4e10 JB	26	#include <linux/fs.h>
	27	#include <linux/kobject.h>
	28	#include <linux/sysfs.h>
4670c46d	29
9c6c877c JB	30	#include "ocfs2_fs.h"
9c6c877c JB	31
286eaa95	32	#include "stackglue.h"
4670c46d	33
9c6c877c JB	34	#define OCFS2_STACK_PLUGIN_O2CB "o2cb"
	35	#define OCFS2_STACK_PLUGIN_USER "user"
	36
286eaa95 JB	37	static struct ocfs2_locking_protocol *lproto;
	38	static DEFINE_SPINLOCK(ocfs2_stack_lock);
	39	static LIST_HEAD(ocfs2_stack_list);
9c6c877c	40	static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
19fdb624	41
286eaa95 JB	42	/*
	43	* The stack currently in use. If not null, active_stack->sp_count > 0,
	44	* the module is pinned, and the locking protocol cannot be changed.
	45	*/
	46	static struct ocfs2_stack_plugin *active_stack;
	47
	48	static struct ocfs2_stack_plugin ocfs2_stack_lookup(const char name)
	49	{
	50	struct ocfs2_stack_plugin *p;
	51
	52	assert_spin_locked(&ocfs2_stack_lock);
	53
	54	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
	55	if (!strcmp(p->sp_name, name))
	56	return p;
	57	}
	58
	59	return NULL;
	60	}
	61
9c6c877c JB	62	static int ocfs2_stack_driver_request(const char *stack_name,
9c6c877c JB	63	const char *plugin_name)
286eaa95 JB	64	{
	65	int rc;
	66	struct ocfs2_stack_plugin *p;
	67
	68	spin_lock(&ocfs2_stack_lock);
	69
9c6c877c JB	70	/*
	71	* If the stack passed by the filesystem isn't the selected one,
	72	* we can't continue.
	73	*/
	74	if (strcmp(stack_name, cluster_stack_name)) {
	75	rc = -EBUSY;
	76	goto out;
	77	}
	78
286eaa95 JB	79	if (active_stack) {
	80	/*
	81	* If the active stack isn't the one we want, it cannot
	82	* be selected right now.
	83	*/
9c6c877c	84	if (!strcmp(active_stack->sp_name, plugin_name))
286eaa95 JB	85	rc = 0;
	86	else
	87	rc = -EBUSY;
	88	goto out;
	89	}
	90
9c6c877c	91	p = ocfs2_stack_lookup(plugin_name);
286eaa95 JB	92	if (!p \|\| !try_module_get(p->sp_owner)) {
	93	rc = -ENOENT;
	94	goto out;
	95	}
	96
	97	/* Ok, the stack is pinned */
	98	p->sp_count++;
	99	active_stack = p;
	100
	101	rc = 0;
	102
	103	out:
	104	spin_unlock(&ocfs2_stack_lock);
	105	return rc;
	106	}
	107
	108	/*
	109	* This function looks up the appropriate stack and makes it active. If
	110	* there is no stack, it tries to load it. It will fail if the stack still
	111	* cannot be found. It will also fail if a different stack is in use.
	112	*/
9c6c877c	113	static int ocfs2_stack_driver_get(const char *stack_name)
286eaa95 JB	114	{
286eaa95 JB	115	int rc;
9c6c877c JB	116	char *plugin_name = OCFS2_STACK_PLUGIN_O2CB;
	117
	118	/*
	119	* Classic stack does not pass in a stack name. This is
	120	* compatible with older tools as well.
	121	*/
	122	if (!stack_name \|\| !*stack_name)
	123	stack_name = OCFS2_STACK_PLUGIN_O2CB;
	124
	125	if (strlen(stack_name) != OCFS2_STACK_LABEL_LEN) {
	126	printk(KERN_ERR
	127	"ocfs2 passed an invalid cluster stack label: \"%s\"\n",
	128	stack_name);
	129	return -EINVAL;
	130	}
286eaa95	131
9c6c877c JB	132	/* Anything that isn't the classic stack is a user stack */
	133	if (strcmp(stack_name, OCFS2_STACK_PLUGIN_O2CB))
	134	plugin_name = OCFS2_STACK_PLUGIN_USER;
	135
	136	rc = ocfs2_stack_driver_request(stack_name, plugin_name);
286eaa95	137	if (rc == -ENOENT) {
9c6c877c JB	138	request_module("ocfs2_stack_%s", plugin_name);
9c6c877c JB	139	rc = ocfs2_stack_driver_request(stack_name, plugin_name);
286eaa95 JB	140	}
	141
	142	if (rc == -ENOENT) {
	143	printk(KERN_ERR
	144	"ocfs2: Cluster stack driver \"%s\" cannot be found\n",
9c6c877c	145	plugin_name);
286eaa95 JB	146	} else if (rc == -EBUSY) {
286eaa95 JB	147	printk(KERN_ERR
9c6c877c	148	"ocfs2: A different cluster stack is in use\n");
286eaa95 JB	149	}
	150
	151	return rc;
	152	}
24ef1815	153
286eaa95 JB	154	static void ocfs2_stack_driver_put(void)
	155	{
	156	spin_lock(&ocfs2_stack_lock);
	157	BUG_ON(active_stack == NULL);
	158	BUG_ON(active_stack->sp_count == 0);
	159
	160	active_stack->sp_count--;
	161	if (!active_stack->sp_count) {
	162	module_put(active_stack->sp_owner);
	163	active_stack = NULL;
	164	}
	165	spin_unlock(&ocfs2_stack_lock);
	166	}
	167
	168	int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin)
	169	{
	170	int rc;
	171
	172	spin_lock(&ocfs2_stack_lock);
	173	if (!ocfs2_stack_lookup(plugin->sp_name)) {
	174	plugin->sp_count = 0;
	175	plugin->sp_proto = lproto;
	176	list_add(&plugin->sp_list, &ocfs2_stack_list);
	177	printk(KERN_INFO "ocfs2: Registered cluster interface %s\n",
	178	plugin->sp_name);
	179	rc = 0;
	180	} else {
	181	printk(KERN_ERR "ocfs2: Stack \"%s\" already registered\n",
	182	plugin->sp_name);
	183	rc = -EEXIST;
	184	}
	185	spin_unlock(&ocfs2_stack_lock);
	186
	187	return rc;
	188	}
	189	EXPORT_SYMBOL_GPL(ocfs2_stack_glue_register);
	190
	191	void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin)
	192	{
	193	struct ocfs2_stack_plugin *p;
	194
	195	spin_lock(&ocfs2_stack_lock);
	196	p = ocfs2_stack_lookup(plugin->sp_name);
	197	if (p) {
	198	BUG_ON(p != plugin);
	199	BUG_ON(plugin == active_stack);
	200	BUG_ON(plugin->sp_count != 0);
	201	list_del_init(&plugin->sp_list);
	202	printk(KERN_INFO "ocfs2: Unregistered cluster interface %s\n",
	203	plugin->sp_name);
	204	} else {
	205	printk(KERN_ERR "Stack \"%s\" is not registered\n",
	206	plugin->sp_name);
	207	}
	208	spin_unlock(&ocfs2_stack_lock);
	209	}
	210	EXPORT_SYMBOL_GPL(ocfs2_stack_glue_unregister);
	211
	212	void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto)
	213	{
	214	struct ocfs2_stack_plugin *p;
	215
	216	BUG_ON(proto == NULL);
	217
218	spin_lock(&ocfs2_stack_lock);
219	BUG_ON(active_stack != NULL);
220
221	lproto = proto;
222	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
223	p->sp_proto = lproto;
224	}
225
226	spin_unlock(&ocfs2_stack_lock);
227	}
228	EXPORT_SYMBOL_GPL(ocfs2_stack_glue_set_locking_protocol);
7431cd7e	229
24ef1815	230
553aa7e4 JB	231	int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
	232	int mode,
	233	union ocfs2_dlm_lksb *lksb,
	234	u32 flags,
	235	void *name,
	236	unsigned int namelen,
	237	void *astarg)
	238	{
286eaa95	239	BUG_ON(lproto == NULL);
bd3e7610	240
286eaa95 JB	241	return active_stack->sp_ops->dlm_lock(conn, mode, lksb, flags,
286eaa95 JB	242	name, namelen, astarg);
24ef1815	243	}
286eaa95	244	EXPORT_SYMBOL_GPL(ocfs2_dlm_lock);
24ef1815	245
553aa7e4 JB	246	int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
	247	union ocfs2_dlm_lksb *lksb,
	248	u32 flags,
	249	void *astarg)
	250	{
286eaa95	251	BUG_ON(lproto == NULL);
553aa7e4	252
286eaa95	253	return active_stack->sp_ops->dlm_unlock(conn, lksb, flags, astarg);
8f2c9c1b	254	}
286eaa95	255	EXPORT_SYMBOL_GPL(ocfs2_dlm_unlock);
8f2c9c1b	256
553aa7e4 JB	257	int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb)
553aa7e4 JB	258	{
286eaa95	259	return active_stack->sp_ops->lock_status(lksb);
553aa7e4	260	}
286eaa95	261	EXPORT_SYMBOL_GPL(ocfs2_dlm_lock_status);
553aa7e4	262
8f2c9c1b JB	263	/*
	264	* Why don't we cast to ocfs2_meta_lvb? The "clean" answer is that we
	265	* don't cast at the glue level. The real answer is that the header
	266	* ordering is nigh impossible.
	267	*/
553aa7e4 JB	268	void ocfs2_dlm_lvb(union ocfs2_dlm_lksb lksb)
553aa7e4 JB	269	{
286eaa95	270	return active_stack->sp_ops->lock_lvb(lksb);
cf0acdcd	271	}
286eaa95	272	EXPORT_SYMBOL_GPL(ocfs2_dlm_lvb);
cf0acdcd	273
553aa7e4 JB	274	void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb)
553aa7e4 JB	275	{
286eaa95	276	active_stack->sp_ops->dump_lksb(lksb);
553aa7e4	277	}
286eaa95	278	EXPORT_SYMBOL_GPL(ocfs2_dlm_dump_lksb);
553aa7e4	279
9c6c877c JB	280	int ocfs2_cluster_connect(const char *stack_name,
9c6c877c JB	281	const char *group,
4670c46d JB	282	int grouplen,
	283	void (*recovery_handler)(int node_num,
	284	void *recovery_data),
	285	void *recovery_data,
	286	struct ocfs2_cluster_connection **conn)
	287	{
	288	int rc = 0;
	289	struct ocfs2_cluster_connection *new_conn;
4670c46d JB	290
	291	BUG_ON(group == NULL);
	292	BUG_ON(conn == NULL);
	293	BUG_ON(recovery_handler == NULL);
	294
	295	if (grouplen > GROUP_NAME_MAX) {
	296	rc = -EINVAL;
	297	goto out;
	298	}
	299
	300	new_conn = kzalloc(sizeof(struct ocfs2_cluster_connection),
	301	GFP_KERNEL);
	302	if (!new_conn) {
	303	rc = -ENOMEM;
	304	goto out;
	305	}
	306
	307	memcpy(new_conn->cc_name, group, grouplen);
	308	new_conn->cc_namelen = grouplen;
	309	new_conn->cc_recovery_handler = recovery_handler;
	310	new_conn->cc_recovery_data = recovery_data;
	311
	312	/* Start the new connection at our maximum compatibility level */
286eaa95 JB	313	new_conn->cc_version = lproto->lp_max_version;
	314
	315	/* This will pin the stack driver if successful */
9c6c877c	316	rc = ocfs2_stack_driver_get(stack_name);
286eaa95 JB	317	if (rc)
286eaa95 JB	318	goto out_free;
4670c46d	319
286eaa95	320	rc = active_stack->sp_ops->connect(new_conn);
553aa7e4	321	if (rc) {
286eaa95	322	ocfs2_stack_driver_put();
4670c46d JB	323	goto out_free;
	324	}
	325
4670c46d JB	326	*conn = new_conn;
	327
	328	out_free:
553aa7e4	329	if (rc)
4670c46d	330	kfree(new_conn);
4670c46d JB	331
	332	out:
	333	return rc;
	334	}
286eaa95	335	EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
4670c46d	336
286eaa95 JB	337	/* If hangup_pending is 0, the stack driver will be dropped */
	338	int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
	339	int hangup_pending)
553aa7e4 JB	340	{
	341	int ret;
	342
	343	BUG_ON(conn == NULL);
	344
286eaa95	345	ret = active_stack->sp_ops->disconnect(conn, hangup_pending);
553aa7e4 JB	346
553aa7e4 JB	347	/* XXX Should we free it anyway? */
286eaa95	348	if (!ret) {
553aa7e4	349	kfree(conn);
286eaa95 JB	350	if (!hangup_pending)
	351	ocfs2_stack_driver_put();
	352	}
553aa7e4 JB	353
	354	return ret;
	355	}
286eaa95	356	EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
553aa7e4	357
6953b4c0 JB	358	void ocfs2_cluster_hangup(const char *group, int grouplen)
	359	{
	360	BUG_ON(group == NULL);
	361	BUG_ON(group[grouplen] != '\0');
	362
286eaa95 JB	363	active_stack->sp_ops->hangup(group, grouplen);
	364
	365	/* cluster_disconnect() was called with hangup_pending==1 */
	366	ocfs2_stack_driver_put();
19fdb624	367	}
286eaa95	368	EXPORT_SYMBOL_GPL(ocfs2_cluster_hangup);
19fdb624	369
553aa7e4 JB	370	int ocfs2_cluster_this_node(unsigned int *node)
553aa7e4 JB	371	{
286eaa95	372	return active_stack->sp_ops->this_node(node);
553aa7e4	373	}
286eaa95	374	EXPORT_SYMBOL_GPL(ocfs2_cluster_this_node);
553aa7e4	375
286eaa95	376
74ae4e10 JB	377	/*
	378	* Sysfs bits
	379	*/
	380
	381	static ssize_t ocfs2_max_locking_protocol_show(struct kobject *kobj,
	382	struct kobj_attribute *attr,
	383	char *buf)
	384	{
	385	ssize_t ret = 0;
	386
	387	spin_lock(&ocfs2_stack_lock);
	388	if (lproto)
	389	ret = snprintf(buf, PAGE_SIZE, "%u.%u\n",
	390	lproto->lp_max_version.pv_major,
	391	lproto->lp_max_version.pv_minor);
	392	spin_unlock(&ocfs2_stack_lock);
	393
	394	return ret;
	395	}
	396
	397	static struct kobj_attribute ocfs2_attr_max_locking_protocol =
	398	__ATTR(max_locking_protocol, S_IFREG \| S_IRUGO,
	399	ocfs2_max_locking_protocol_show, NULL);
	400
	401	static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
	402	struct kobj_attribute *attr,
	403	char *buf)
24ef1815	404	{
74ae4e10 JB	405	ssize_t ret = 0, total = 0, remain = PAGE_SIZE;
	406	struct ocfs2_stack_plugin *p;
	407
	408	spin_lock(&ocfs2_stack_lock);
	409	list_for_each_entry(p, &ocfs2_stack_list, sp_list) {
	410	ret = snprintf(buf, remain, "%s\n",
	411	p->sp_name);
	412	if (ret < 0) {
	413	total = ret;
	414	break;
	415	}
	416	if (ret == remain) {
	417	/* snprintf() didn't fit */
	418	total = -E2BIG;
	419	break;
	420	}
	421	total += ret;
	422	remain -= ret;
	423	}
	424	spin_unlock(&ocfs2_stack_lock);
	425
	426	return total;
	427	}
	428
	429	static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
	430	__ATTR(loaded_cluster_plugins, S_IFREG \| S_IRUGO,
	431	ocfs2_loaded_cluster_plugins_show, NULL);
	432
	433	static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
	434	struct kobj_attribute *attr,
	435	char *buf)
	436	{
	437	ssize_t ret = 0;
	438
	439	spin_lock(&ocfs2_stack_lock);
	440	if (active_stack) {
	441	ret = snprintf(buf, PAGE_SIZE, "%s\n",
	442	active_stack->sp_name);
	443	if (ret == PAGE_SIZE)
	444	ret = -E2BIG;
	445	}
	446	spin_unlock(&ocfs2_stack_lock);
	447
	448	return ret;
	449	}
	450
	451	static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
	452	__ATTR(active_cluster_plugin, S_IFREG \| S_IRUGO,
	453	ocfs2_active_cluster_plugin_show, NULL);
	454
9c6c877c JB	455	static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
	456	struct kobj_attribute *attr,
	457	char *buf)
	458	{
	459	ssize_t ret;
	460	spin_lock(&ocfs2_stack_lock);
	461	ret = snprintf(buf, PAGE_SIZE, "%s\n", cluster_stack_name);
	462	spin_unlock(&ocfs2_stack_lock);
	463
	464	return ret;
	465	}
	466
	467	static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
	468	struct kobj_attribute *attr,
	469	const char *buf, size_t count)
	470	{
	471	size_t len = count;
	472	ssize_t ret;
	473
	474	if (len == 0)
	475	return len;
	476
	477	if (buf[len - 1] == '\n')
	478	len--;
	479
	480	if ((len != OCFS2_STACK_LABEL_LEN) \|\|
	481	(strnlen(buf, len) != len))
	482	return -EINVAL;
	483
	484	spin_lock(&ocfs2_stack_lock);
	485	if (active_stack) {
	486	if (!strncmp(buf, cluster_stack_name, len))
	487	ret = count;
	488	else
	489	ret = -EBUSY;
	490	} else {
	491	memcpy(cluster_stack_name, buf, len);
	492	ret = count;
	493	}
	494	spin_unlock(&ocfs2_stack_lock);
	495
	496	return ret;
	497	}
	498
	499
	500	static struct kobj_attribute ocfs2_attr_cluster_stack =
	501	__ATTR(cluster_stack, S_IFREG \| S_IRUGO \| S_IWUSR,
	502	ocfs2_cluster_stack_show,
	503	ocfs2_cluster_stack_store);
	504
74ae4e10 JB	505	static struct attribute *ocfs2_attrs[] = {
	506	&ocfs2_attr_max_locking_protocol.attr,
	507	&ocfs2_attr_loaded_cluster_plugins.attr,
	508	&ocfs2_attr_active_cluster_plugin.attr,
9c6c877c	509	&ocfs2_attr_cluster_stack.attr,
74ae4e10 JB	510	NULL,
	511	};
	512
	513	static struct attribute_group ocfs2_attr_group = {
	514	.attrs = ocfs2_attrs,
	515	};
	516
	517	static struct kset *ocfs2_kset;
	518
	519	static void ocfs2_sysfs_exit(void)
	520	{
	521	kset_unregister(ocfs2_kset);
	522	}
	523
	524	static int ocfs2_sysfs_init(void)
	525	{
	526	int ret;
	527
	528	ocfs2_kset = kset_create_and_add("ocfs2", NULL, fs_kobj);
	529	if (!ocfs2_kset)
	530	return -ENOMEM;
	531
	532	ret = sysfs_create_group(&ocfs2_kset->kobj, &ocfs2_attr_group);
	533	if (ret)
	534	goto error;
	535
286eaa95	536	return 0;
74ae4e10 JB	537
	538	error:
	539	kset_unregister(ocfs2_kset);
	540	return ret;
	541	}
	542
	543	static int __init ocfs2_stack_glue_init(void)
	544	{
9c6c877c JB	545	strcpy(cluster_stack_name, OCFS2_STACK_PLUGIN_O2CB);
9c6c877c JB	546
74ae4e10	547	return ocfs2_sysfs_init();
286eaa95	548	}
24ef1815	549
286eaa95 JB	550	static void __exit ocfs2_stack_glue_exit(void)
	551	{
	552	lproto = NULL;
74ae4e10	553	ocfs2_sysfs_exit();
24ef1815 JB	554	}
24ef1815 JB	555
286eaa95 JB	556	MODULE_AUTHOR("Oracle");
	557	MODULE_DESCRIPTION("ocfs2 cluter stack glue layer");
	558	MODULE_LICENSE("GPL");
	559	module_init(ocfs2_stack_glue_init);
	560	module_exit(ocfs2_stack_glue_exit);