[net-next-2.6.git] / fs / gfs2 / locking / dlm / plock.c

/*
 * Copyright (C) 2005 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/miscdevice.h>
#include <linux/lock_dlm_plock.h>
#include <linux/poll.h>

#include "lock_dlm.h"


static spinlock_t ops_lock;
static struct list_head send_list;
static struct list_head recv_list;
static wait_queue_head_t send_wq;
static wait_queue_head_t recv_wq;

struct plock_op {
	struct list_head list;
	int done;
	struct gdlm_plock_info info;
};

static inline void set_version(struct gdlm_plock_info *info)
{
	info->version[0] = GDLM_PLOCK_VERSION_MAJOR;
	info->version[1] = GDLM_PLOCK_VERSION_MINOR;
	info->version[2] = GDLM_PLOCK_VERSION_PATCH;
}

static int check_version(struct gdlm_plock_info *info)
{
	if ((GDLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
	    (GDLM_PLOCK_VERSION_MINOR < info->version[1])) {
		log_error("plock device version mismatch: "
			  "kernel (%u.%u.%u), user (%u.%u.%u)",
			  GDLM_PLOCK_VERSION_MAJOR,
			  GDLM_PLOCK_VERSION_MINOR,
			  GDLM_PLOCK_VERSION_PATCH,
			  info->version[0],
			  info->version[1],
			  info->version[2]);
		return -EINVAL;
	}
	return 0;
}

static void send_op(struct plock_op *op)
{
	set_version(&op->info);
	INIT_LIST_HEAD(&op->list);
	spin_lock(&ops_lock);
	list_add_tail(&op->list, &send_list);
	spin_unlock(&ops_lock);
	wake_up(&send_wq);
}

int gdlm_plock(void *lockspace, struct lm_lockname *name,
	       struct file *file, int cmd, struct file_lock *fl)
{
	struct gdlm_ls *ls = lockspace;
	struct plock_op *op;
	int rv;

	op = kzalloc(sizeof(*op), GFP_KERNEL);
	if (!op)
		return -ENOMEM;

	op->info.optype		= GDLM_PLOCK_OP_LOCK;
	op->info.pid		= fl->fl_pid;
	op->info.ex		= (fl->fl_type == F_WRLCK);
	op->info.wait		= IS_SETLKW(cmd);
	op->info.fsid		= ls->id;
	op->info.number		= name->ln_number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	op->info.owner		= (__u64)(long) fl->fl_owner;

	send_op(op);
	wait_event(recv_wq, (op->done != 0));

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		printk(KERN_INFO "plock op on list\n");
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	if (!rv) {
		if (posix_lock_file_wait(file, fl) < 0)
			log_error("gdlm_plock: vfs lock error %x,%llx",
				  name->ln_type,
				  (unsigned long long)name->ln_number);
	}

	kfree(op);
	return rv;
}

int gdlm_punlock(void *lockspace, struct lm_lockname *name,
		 struct file *file, struct file_lock *fl)
{
	struct gdlm_ls *ls = lockspace;
	struct plock_op *op;
	int rv;

	op = kzalloc(sizeof(*op), GFP_KERNEL);
	if (!op)
		return -ENOMEM;

	if (posix_lock_file_wait(file, fl) < 0)
		log_error("gdlm_punlock: vfs unlock error %x,%llx",
			  name->ln_type, (unsigned long long)name->ln_number);

	op->info.optype		= GDLM_PLOCK_OP_UNLOCK;
	op->info.pid		= fl->fl_pid;
	op->info.fsid		= ls->id;
	op->info.number		= name->ln_number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	op->info.owner		= (__u64)(long) fl->fl_owner;

	send_op(op);
	wait_event(recv_wq, (op->done != 0));

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		printk(KERN_INFO "punlock op on list\n");
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	kfree(op);
	return rv;
}

int gdlm_plock_get(void *lockspace, struct lm_lockname *name,
		   struct file *file, struct file_lock *fl)
{
	struct gdlm_ls *ls = lockspace;
	struct plock_op *op;
	int rv;

	op = kzalloc(sizeof(*op), GFP_KERNEL);
	if (!op)
		return -ENOMEM;

	op->info.optype		= GDLM_PLOCK_OP_GET;
	op->info.pid		= fl->fl_pid;
	op->info.ex		= (fl->fl_type == F_WRLCK);
	op->info.fsid		= ls->id;
	op->info.number		= name->ln_number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;

	send_op(op);
	wait_event(recv_wq, (op->done != 0));

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		printk(KERN_INFO "plock_get op on list\n");
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	if (rv == 0)
		fl->fl_type = F_UNLCK;
	else if (rv > 0) {
		fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
		fl->fl_pid = op->info.pid;
		fl->fl_start = op->info.start;
		fl->fl_end = op->info.end;
	}

	kfree(op);
	return rv;
}

/* a read copies out one plock request from the send list */
static ssize_t dev_read(struct file *file, char __user *u, size_t count,
			loff_t *ppos)
{
	struct gdlm_plock_info info;
	struct plock_op *op = NULL;

	if (count < sizeof(info))
		return -EINVAL;

	spin_lock(&ops_lock);
	if (!list_empty(&send_list)) {
		op = list_entry(send_list.next, struct plock_op, list);
		list_move(&op->list, &recv_list);
		memcpy(&info, &op->info, sizeof(info));
	}
	spin_unlock(&ops_lock);

	if (!op)
		return -EAGAIN;

	if (copy_to_user(u, &info, sizeof(info)))
		return -EFAULT;
	return sizeof(info);
}

/* a write copies in one plock result that should match a plock_op
   on the recv list */
static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
			 loff_t *ppos)
{
	struct gdlm_plock_info info;
	struct plock_op *op;
	int found = 0;

	if (count != sizeof(info))
		return -EINVAL;

	if (copy_from_user(&info, u, sizeof(info)))
		return -EFAULT;

	if (check_version(&info))
		return -EINVAL;

	spin_lock(&ops_lock);
	list_for_each_entry(op, &recv_list, list) {
		if (op->info.fsid == info.fsid && op->info.number == info.number &&
		    op->info.owner == info.owner) {
			list_del_init(&op->list);
			found = 1;
			op->done = 1;
			memcpy(&op->info, &info, sizeof(info));
			break;
		}
	}
	spin_unlock(&ops_lock);

	if (found)
		wake_up(&recv_wq);
	else
		printk(KERN_INFO "gdlm dev_write no op %x %llx\n", info.fsid,
			(unsigned long long)info.number);
	return count;
}

static unsigned int dev_poll(struct file *file, poll_table *wait)
{
	poll_wait(file, &send_wq, wait);

	spin_lock(&ops_lock);
	if (!list_empty(&send_list)) {
		spin_unlock(&ops_lock);
		return POLLIN | POLLRDNORM;
	}
	spin_unlock(&ops_lock);
	return 0;
}

static struct file_operations dev_fops = {
	.read    = dev_read,
	.write   = dev_write,
	.poll    = dev_poll,
	.owner   = THIS_MODULE
};

static struct miscdevice plock_dev_misc = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = GDLM_PLOCK_MISC_NAME,
	.fops = &dev_fops
};

int gdlm_plock_init(void)
{
	int rv;

	spin_lock_init(&ops_lock);
	INIT_LIST_HEAD(&send_list);
	INIT_LIST_HEAD(&recv_list);
	init_waitqueue_head(&send_wq);
	init_waitqueue_head(&recv_wq);

	rv = misc_register(&plock_dev_misc);
	if (rv)
		printk(KERN_INFO "gdlm_plock_init: misc_register failed %d",
		       rv);
	return rv;
}

void gdlm_plock_exit(void)
{
	if (misc_deregister(&plock_dev_misc) < 0)
		printk(KERN_INFO "gdlm_plock_exit: misc_deregister failed");
}
Commit	Line	Data
869d81df DT	1	/*
	2	* Copyright (C) 2005 Red Hat, Inc. All rights reserved.
	3	*
	4	* This copyrighted material is made available to anyone wishing to use,
	5	* modify, copy, or redistribute it subject to the terms and conditions
e9fc2aa0	6	* of the GNU General Public License version 2.
869d81df DT	7	*/
	8
	9	#include <linux/miscdevice.h>
	10	#include <linux/lock_dlm_plock.h>
bd01f843	11	#include <linux/poll.h>
869d81df DT	12
	13	#include "lock_dlm.h"
	14
	15
	16	static spinlock_t ops_lock;
	17	static struct list_head send_list;
	18	static struct list_head recv_list;
	19	static wait_queue_head_t send_wq;
	20	static wait_queue_head_t recv_wq;
	21
	22	struct plock_op {
	23	struct list_head list;
	24	int done;
	25	struct gdlm_plock_info info;
	26	};
	27
	28	static inline void set_version(struct gdlm_plock_info *info)
	29	{
	30	info->version[0] = GDLM_PLOCK_VERSION_MAJOR;
	31	info->version[1] = GDLM_PLOCK_VERSION_MINOR;
	32	info->version[2] = GDLM_PLOCK_VERSION_PATCH;
	33	}
	34
	35	static int check_version(struct gdlm_plock_info *info)
	36	{
	37	if ((GDLM_PLOCK_VERSION_MAJOR != info->version[0]) \|\|
	38	(GDLM_PLOCK_VERSION_MINOR < info->version[1])) {
	39	log_error("plock device version mismatch: "
	40	"kernel (%u.%u.%u), user (%u.%u.%u)",
	41	GDLM_PLOCK_VERSION_MAJOR,
	42	GDLM_PLOCK_VERSION_MINOR,
	43	GDLM_PLOCK_VERSION_PATCH,
	44	info->version[0],
	45	info->version[1],
	46	info->version[2]);
	47	return -EINVAL;
	48	}
	49	return 0;
	50	}
	51
	52	static void send_op(struct plock_op *op)
	53	{
	54	set_version(&op->info);
	55	INIT_LIST_HEAD(&op->list);
	56	spin_lock(&ops_lock);
	57	list_add_tail(&op->list, &send_list);
	58	spin_unlock(&ops_lock);
	59	wake_up(&send_wq);
	60	}
	61
9b47c11d	62	int gdlm_plock(void lockspace, struct lm_lockname name,
869d81df DT	63	struct file file, int cmd, struct file_lock fl)
869d81df DT	64	{
9b47c11d	65	struct gdlm_ls *ls = lockspace;
869d81df DT	66	struct plock_op *op;
	67	int rv;
	68
	69	op = kzalloc(sizeof(*op), GFP_KERNEL);
	70	if (!op)
	71	return -ENOMEM;
	72
	73	op->info.optype = GDLM_PLOCK_OP_LOCK;
3a2a9c96	74	op->info.pid = fl->fl_pid;
869d81df DT	75	op->info.ex = (fl->fl_type == F_WRLCK);
	76	op->info.wait = IS_SETLKW(cmd);
	77	op->info.fsid = ls->id;
	78	op->info.number = name->ln_number;
	79	op->info.start = fl->fl_start;
	80	op->info.end = fl->fl_end;
de9b75d3	81	op->info.owner = (__u64)(long) fl->fl_owner;
869d81df DT	82
	83	send_op(op);
	84	wait_event(recv_wq, (op->done != 0));
	85
	86	spin_lock(&ops_lock);
	87	if (!list_empty(&op->list)) {
d92a8d48	88	printk(KERN_INFO "plock op on list\n");
869d81df DT	89	list_del(&op->list);
	90	}
	91	spin_unlock(&ops_lock);
	92
	93	rv = op->info.rv;
	94
	95	if (!rv) {
	96	if (posix_lock_file_wait(file, fl) < 0)
	97	log_error("gdlm_plock: vfs lock error %x,%llx",
9229f013 DT	98	name->ln_type,
9229f013 DT	99	(unsigned long long)name->ln_number);
869d81df DT	100	}
	101
	102	kfree(op);
	103	return rv;
	104	}
	105
9b47c11d	106	int gdlm_punlock(void lockspace, struct lm_lockname name,
869d81df DT	107	struct file file, struct file_lock fl)
869d81df DT	108	{
9b47c11d	109	struct gdlm_ls *ls = lockspace;
869d81df DT	110	struct plock_op *op;
	111	int rv;
	112
	113	op = kzalloc(sizeof(*op), GFP_KERNEL);
	114	if (!op)
	115	return -ENOMEM;
	116
	117	if (posix_lock_file_wait(file, fl) < 0)
	118	log_error("gdlm_punlock: vfs unlock error %x,%llx",
9229f013	119	name->ln_type, (unsigned long long)name->ln_number);
869d81df DT	120
869d81df DT	121	op->info.optype = GDLM_PLOCK_OP_UNLOCK;
3a2a9c96	122	op->info.pid = fl->fl_pid;
869d81df DT	123	op->info.fsid = ls->id;
	124	op->info.number = name->ln_number;
	125	op->info.start = fl->fl_start;
	126	op->info.end = fl->fl_end;
de9b75d3	127	op->info.owner = (__u64)(long) fl->fl_owner;
869d81df DT	128
	129	send_op(op);
	130	wait_event(recv_wq, (op->done != 0));
	131
	132	spin_lock(&ops_lock);
	133	if (!list_empty(&op->list)) {
d92a8d48	134	printk(KERN_INFO "punlock op on list\n");
869d81df DT	135	list_del(&op->list);
	136	}
	137	spin_unlock(&ops_lock);
	138
	139	rv = op->info.rv;
	140
	141	kfree(op);
	142	return rv;
	143	}
	144
9b47c11d	145	int gdlm_plock_get(void lockspace, struct lm_lockname name,
869d81df DT	146	struct file file, struct file_lock fl)
869d81df DT	147	{
9b47c11d	148	struct gdlm_ls *ls = lockspace;
869d81df DT	149	struct plock_op *op;
	150	int rv;
	151
	152	op = kzalloc(sizeof(*op), GFP_KERNEL);
	153	if (!op)
	154	return -ENOMEM;
	155
	156	op->info.optype = GDLM_PLOCK_OP_GET;
3a2a9c96	157	op->info.pid = fl->fl_pid;
869d81df DT	158	op->info.ex = (fl->fl_type == F_WRLCK);
	159	op->info.fsid = ls->id;
	160	op->info.number = name->ln_number;
	161	op->info.start = fl->fl_start;
	162	op->info.end = fl->fl_end;
	163
	164	send_op(op);
	165	wait_event(recv_wq, (op->done != 0));
	166
	167	spin_lock(&ops_lock);
	168	if (!list_empty(&op->list)) {
d92a8d48	169	printk(KERN_INFO "plock_get op on list\n");
869d81df DT	170	list_del(&op->list);
	171	}
	172	spin_unlock(&ops_lock);
	173
	174	rv = op->info.rv;
	175
	176	if (rv == 0)
	177	fl->fl_type = F_UNLCK;
	178	else if (rv > 0) {
	179	fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
	180	fl->fl_pid = op->info.pid;
	181	fl->fl_start = op->info.start;
	182	fl->fl_end = op->info.end;
	183	}
	184
	185	kfree(op);
	186	return rv;
	187	}
	188
	189	/* a read copies out one plock request from the send list */
	190	static ssize_t dev_read(struct file file, char __user u, size_t count,
	191	loff_t *ppos)
	192	{
	193	struct gdlm_plock_info info;
	194	struct plock_op *op = NULL;
	195
	196	if (count < sizeof(info))
	197	return -EINVAL;
	198
	199	spin_lock(&ops_lock);
	200	if (!list_empty(&send_list)) {
	201	op = list_entry(send_list.next, struct plock_op, list);
	202	list_move(&op->list, &recv_list);
	203	memcpy(&info, &op->info, sizeof(info));
	204	}
	205	spin_unlock(&ops_lock);
	206
	207	if (!op)
	208	return -EAGAIN;
	209
	210	if (copy_to_user(u, &info, sizeof(info)))
	211	return -EFAULT;
	212	return sizeof(info);
	213	}
	214
	215	/* a write copies in one plock result that should match a plock_op
	216	on the recv list */
	217	static ssize_t dev_write(struct file file, const char __user u, size_t count,
	218	loff_t *ppos)
	219	{
	220	struct gdlm_plock_info info;
	221	struct plock_op *op;
	222	int found = 0;
	223
	224	if (count != sizeof(info))
	225	return -EINVAL;
	226
	227	if (copy_from_user(&info, u, sizeof(info)))
	228	return -EFAULT;
	229
	230	if (check_version(&info))
	231	return -EINVAL;
	232
	233	spin_lock(&ops_lock);
234	list_for_each_entry(op, &recv_list, list) {
9b47c11d	235	if (op->info.fsid == info.fsid && op->info.number == info.number &&
08eac93a	236	op->info.owner == info.owner) {
869d81df DT	237	list_del_init(&op->list);
	238	found = 1;
	239	op->done = 1;
	240	memcpy(&op->info, &info, sizeof(info));
	241	break;
	242	}
	243	}
	244	spin_unlock(&ops_lock);
	245
	246	if (found)
	247	wake_up(&recv_wq);
	248	else
d92a8d48	249	printk(KERN_INFO "gdlm dev_write no op %x %llx\n", info.fsid,
9229f013	250	(unsigned long long)info.number);
869d81df DT	251	return count;
	252	}
	253
	254	static unsigned int dev_poll(struct file file, poll_table wait)
	255	{
	256	poll_wait(file, &send_wq, wait);
	257
	258	spin_lock(&ops_lock);
	259	if (!list_empty(&send_list)) {
	260	spin_unlock(&ops_lock);
	261	return POLLIN \| POLLRDNORM;
	262	}
	263	spin_unlock(&ops_lock);
	264	return 0;
	265	}
	266
	267	static struct file_operations dev_fops = {
	268	.read = dev_read,
	269	.write = dev_write,
	270	.poll = dev_poll,
	271	.owner = THIS_MODULE
	272	};
	273
	274	static struct miscdevice plock_dev_misc = {
	275	.minor = MISC_DYNAMIC_MINOR,
	276	.name = GDLM_PLOCK_MISC_NAME,
	277	.fops = &dev_fops
	278	};
	279
	280	int gdlm_plock_init(void)
	281	{
	282	int rv;
	283
	284	spin_lock_init(&ops_lock);
	285	INIT_LIST_HEAD(&send_list);
	286	INIT_LIST_HEAD(&recv_list);
	287	init_waitqueue_head(&send_wq);
	288	init_waitqueue_head(&recv_wq);
	289
	290	rv = misc_register(&plock_dev_misc);
	291	if (rv)
d92a8d48 SW	292	printk(KERN_INFO "gdlm_plock_init: misc_register failed %d",
d92a8d48 SW	293	rv);
869d81df DT	294	return rv;
	295	}
	296
	297	void gdlm_plock_exit(void)
	298	{
	299	if (misc_deregister(&plock_dev_misc) < 0)
d92a8d48	300	printk(KERN_INFO "gdlm_plock_exit: misc_deregister failed");
869d81df DT	301	}
869d81df DT	302