[linux.git] / fs / dlm / plock.c

/*
 * Copyright (C) 2005-2008 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/fs.h>
#include <linux/miscdevice.h>
#include <linux/poll.h>
#include <linux/dlm.h>
#include <linux/dlm_plock.h>
#include <linux/slab.h>

#include "dlm_internal.h"
#include "lockspace.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 dlm_plock_info info;
};

struct plock_xop {
	struct plock_op xop;
	int (*callback)(struct file_lock *fl, int result);
	void *fl;
	void *file;
	struct file_lock flc;
};


static inline void set_version(struct dlm_plock_info *info)
{
	info->version[0] = DLM_PLOCK_VERSION_MAJOR;
	info->version[1] = DLM_PLOCK_VERSION_MINOR;
	info->version[2] = DLM_PLOCK_VERSION_PATCH;
}

static int check_version(struct dlm_plock_info *info)
{
	if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
	    (DLM_PLOCK_VERSION_MINOR < info->version[1])) {
		log_print("plock device version mismatch: "
			  "kernel (%u.%u.%u), user (%u.%u.%u)",
			  DLM_PLOCK_VERSION_MAJOR,
			  DLM_PLOCK_VERSION_MINOR,
			  DLM_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);
}

/* If a process was killed while waiting for the only plock on a file,
   locks_remove_posix will not see any lock on the file so it won't
   send an unlock-close to us to pass on to userspace to clean up the
   abandoned waiter.  So, we have to insert the unlock-close when the
   lock call is interrupted. */

static void do_unlock_close(struct dlm_ls *ls, u64 number,
			    struct file *file, struct file_lock *fl)
{
	struct plock_op *op;

	op = kzalloc(sizeof(*op), GFP_NOFS);
	if (!op)
		return;

	op->info.optype		= DLM_PLOCK_OP_UNLOCK;
	op->info.pid		= fl->fl_pid;
	op->info.fsid		= ls->ls_global_id;
	op->info.number		= number;
	op->info.start		= 0;
	op->info.end		= OFFSET_MAX;
	if (fl->fl_lmops && fl->fl_lmops->lm_grant)
		op->info.owner	= (__u64) fl->fl_pid;
	else
		op->info.owner	= (__u64)(long) fl->fl_owner;

	op->info.flags |= DLM_PLOCK_FL_CLOSE;
	send_op(op);
}

int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
		   int cmd, struct file_lock *fl)
{
	struct dlm_ls *ls;
	struct plock_op *op;
	struct plock_xop *xop;
	int rv;

	ls = dlm_find_lockspace_local(lockspace);
	if (!ls)
		return -EINVAL;

	xop = kzalloc(sizeof(*xop), GFP_NOFS);
	if (!xop) {
		rv = -ENOMEM;
		goto out;
	}

	op = &xop->xop;
	op->info.optype		= DLM_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->ls_global_id;
	op->info.number		= number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
		/* fl_owner is lockd which doesn't distinguish
		   processes on the nfs client */
		op->info.owner	= (__u64) fl->fl_pid;
		xop->callback	= fl->fl_lmops->lm_grant;
		locks_init_lock(&xop->flc);
		locks_copy_lock(&xop->flc, fl);
		xop->fl		= fl;
		xop->file	= file;
	} else {
		op->info.owner	= (__u64)(long) fl->fl_owner;
		xop->callback	= NULL;
	}

	send_op(op);

	if (xop->callback == NULL) {
		rv = wait_event_interruptible(recv_wq, (op->done != 0));
		if (rv == -ERESTARTSYS) {
			log_debug(ls, "dlm_posix_lock: wait killed %llx",
				  (unsigned long long)number);
			spin_lock(&ops_lock);
			list_del(&op->list);
			spin_unlock(&ops_lock);
			kfree(xop);
			do_unlock_close(ls, number, file, fl);
			goto out;
		}
	} else {
		rv = FILE_LOCK_DEFERRED;
		goto out;
	}

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		log_error(ls, "dlm_posix_lock: op on list %llx",
			  (unsigned long long)number);
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	if (!rv) {
		if (locks_lock_file_wait(file, fl) < 0)
			log_error(ls, "dlm_posix_lock: vfs lock error %llx",
				  (unsigned long long)number);
	}

	kfree(xop);
out:
	dlm_put_lockspace(ls);
	return rv;
}
EXPORT_SYMBOL_GPL(dlm_posix_lock);

/* Returns failure iff a successful lock operation should be canceled */
static int dlm_plock_callback(struct plock_op *op)
{
	struct file *file;
	struct file_lock *fl;
	struct file_lock *flc;
	int (*notify)(struct file_lock *fl, int result) = NULL;
	struct plock_xop *xop = (struct plock_xop *)op;
	int rv = 0;

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		log_print("dlm_plock_callback: op on list %llx",
			  (unsigned long long)op->info.number);
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	/* check if the following 2 are still valid or make a copy */
	file = xop->file;
	flc = &xop->flc;
	fl = xop->fl;
	notify = xop->callback;

	if (op->info.rv) {
		notify(fl, op->info.rv);
		goto out;
	}

	/* got fs lock; bookkeep locally as well: */
	flc->fl_flags &= ~FL_SLEEP;
	if (posix_lock_file(file, flc, NULL)) {
		/*
		 * This can only happen in the case of kmalloc() failure.
		 * The filesystem's own lock is the authoritative lock,
		 * so a failure to get the lock locally is not a disaster.
		 * As long as the fs cannot reliably cancel locks (especially
		 * in a low-memory situation), we're better off ignoring
		 * this failure than trying to recover.
		 */
		log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
			  (unsigned long long)op->info.number, file, fl);
	}

	rv = notify(fl, 0);
	if (rv) {
		/* XXX: We need to cancel the fs lock here: */
		log_print("dlm_plock_callback: lock granted after lock request "
			  "failed; dangling lock!\n");
		goto out;
	}

out:
	kfree(xop);
	return rv;
}

int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
		     struct file_lock *fl)
{
	struct dlm_ls *ls;
	struct plock_op *op;
	int rv;
	unsigned char fl_flags = fl->fl_flags;

	ls = dlm_find_lockspace_local(lockspace);
	if (!ls)
		return -EINVAL;

	op = kzalloc(sizeof(*op), GFP_NOFS);
	if (!op) {
		rv = -ENOMEM;
		goto out;
	}

	/* cause the vfs unlock to return ENOENT if lock is not found */
	fl->fl_flags |= FL_EXISTS;

	rv = locks_lock_file_wait(file, fl);
	if (rv == -ENOENT) {
		rv = 0;
		goto out_free;
	}
	if (rv < 0) {
		log_error(ls, "dlm_posix_unlock: vfs unlock error %d %llx",
			  rv, (unsigned long long)number);
	}

	op->info.optype		= DLM_PLOCK_OP_UNLOCK;
	op->info.pid		= fl->fl_pid;
	op->info.fsid		= ls->ls_global_id;
	op->info.number		= number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	if (fl->fl_lmops && fl->fl_lmops->lm_grant)
		op->info.owner	= (__u64) fl->fl_pid;
	else
		op->info.owner	= (__u64)(long) fl->fl_owner;

	if (fl->fl_flags & FL_CLOSE) {
		op->info.flags |= DLM_PLOCK_FL_CLOSE;
		send_op(op);
		rv = 0;
		goto out;
	}

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

	spin_lock(&ops_lock);
	if (!list_empty(&op->list)) {
		log_error(ls, "dlm_posix_unlock: op on list %llx",
			  (unsigned long long)number);
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	rv = op->info.rv;

	if (rv == -ENOENT)
		rv = 0;

out_free:
	kfree(op);
out:
	dlm_put_lockspace(ls);
	fl->fl_flags = fl_flags;
	return rv;
}
EXPORT_SYMBOL_GPL(dlm_posix_unlock);

int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
		  struct file_lock *fl)
{
	struct dlm_ls *ls;
	struct plock_op *op;
	int rv;

	ls = dlm_find_lockspace_local(lockspace);
	if (!ls)
		return -EINVAL;

	op = kzalloc(sizeof(*op), GFP_NOFS);
	if (!op) {
		rv = -ENOMEM;
		goto out;
	}

	op->info.optype		= DLM_PLOCK_OP_GET;
	op->info.pid		= fl->fl_pid;
	op->info.ex		= (fl->fl_type == F_WRLCK);
	op->info.fsid		= ls->ls_global_id;
	op->info.number		= number;
	op->info.start		= fl->fl_start;
	op->info.end		= fl->fl_end;
	if (fl->fl_lmops && fl->fl_lmops->lm_grant)
		op->info.owner	= (__u64) fl->fl_pid;
	else
		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)) {
		log_error(ls, "dlm_posix_get: op on list %llx",
			  (unsigned long long)number);
		list_del(&op->list);
	}
	spin_unlock(&ops_lock);

	/* info.rv from userspace is 1 for conflict, 0 for no-conflict,
	   -ENOENT if there are no locks on the file */

	rv = op->info.rv;

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

	kfree(op);
out:
	dlm_put_lockspace(ls);
	return rv;
}
EXPORT_SYMBOL_GPL(dlm_posix_get);

/* 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 dlm_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);
		if (op->info.flags & DLM_PLOCK_FL_CLOSE)
			list_del(&op->list);
		else
			list_move(&op->list, &recv_list);
		memcpy(&info, &op->info, sizeof(info));
	}
	spin_unlock(&ops_lock);

	if (!op)
		return -EAGAIN;

	/* there is no need to get a reply from userspace for unlocks
	   that were generated by the vfs cleaning up for a close
	   (the process did not make an unlock call). */

	if (op->info.flags & DLM_PLOCK_FL_CLOSE)
		kfree(op);

	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 dlm_plock_info info;
	struct plock_op *op;
	int found = 0, do_callback = 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) {
			struct plock_xop *xop = (struct plock_xop *)op;
			list_del_init(&op->list);
			memcpy(&op->info, &info, sizeof(info));
			if (xop->callback)
				do_callback = 1;
			else
				op->done = 1;
			found = 1;
			break;
		}
	}
	spin_unlock(&ops_lock);

	if (found) {
		if (do_callback)
			dlm_plock_callback(op);
		else
			wake_up(&recv_wq);
	} else
		log_print("dev_write no op %x %llx", info.fsid,
			  (unsigned long long)info.number);
	return count;
}

static unsigned int dev_poll(struct file *file, poll_table *wait)
{
	unsigned int mask = 0;

	poll_wait(file, &send_wq, wait);

	spin_lock(&ops_lock);
	if (!list_empty(&send_list))
		mask = POLLIN | POLLRDNORM;
	spin_unlock(&ops_lock);

	return mask;
}

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

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

int dlm_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)
		log_print("dlm_plock_init: misc_register failed %d", rv);
	return rv;
}

void dlm_plock_exit(void)
{
	misc_deregister(&plock_dev_misc);
}
Commit	Line	Data
869d81df	1	/*
2402211a	2	* Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
869d81df DT	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	*/
869d81df DT	8
2402211a	9	#include <linux/fs.h>
869d81df	10	#include <linux/miscdevice.h>
bd01f843	11	#include <linux/poll.h>
2402211a DT	12	#include <linux/dlm.h>
2402211a DT	13	#include <linux/dlm_plock.h>
5a0e3ad6	14	#include <linux/slab.h>
869d81df	15
2402211a DT	16	#include "dlm_internal.h"
2402211a DT	17	#include "lockspace.h"
869d81df DT	18
	19	static spinlock_t ops_lock;
	20	static struct list_head send_list;
	21	static struct list_head recv_list;
	22	static wait_queue_head_t send_wq;
	23	static wait_queue_head_t recv_wq;
	24
	25	struct plock_op {
	26	struct list_head list;
	27	int done;
2402211a	28	struct dlm_plock_info info;
869d81df DT	29	};
869d81df DT	30
586759f0 ME	31	struct plock_xop {
586759f0 ME	32	struct plock_op xop;
d0449b90	33	int (callback)(struct file_lock fl, int result);
586759f0 ME	34	void *fl;
	35	void *file;
	36	struct file_lock flc;
	37	};
	38
	39
2402211a	40	static inline void set_version(struct dlm_plock_info *info)
869d81df	41	{
2402211a DT	42	info->version[0] = DLM_PLOCK_VERSION_MAJOR;
	43	info->version[1] = DLM_PLOCK_VERSION_MINOR;
	44	info->version[2] = DLM_PLOCK_VERSION_PATCH;
869d81df DT	45	}
869d81df DT	46
2402211a	47	static int check_version(struct dlm_plock_info *info)
869d81df	48	{
2402211a DT	49	if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) \|\|
	50	(DLM_PLOCK_VERSION_MINOR < info->version[1])) {
	51	log_print("plock device version mismatch: "
869d81df	52	"kernel (%u.%u.%u), user (%u.%u.%u)",
2402211a DT	53	DLM_PLOCK_VERSION_MAJOR,
	54	DLM_PLOCK_VERSION_MINOR,
	55	DLM_PLOCK_VERSION_PATCH,
869d81df DT	56	info->version[0],
	57	info->version[1],
	58	info->version[2]);
	59	return -EINVAL;
	60	}
	61	return 0;
	62	}
	63
	64	static void send_op(struct plock_op *op)
	65	{
	66	set_version(&op->info);
	67	INIT_LIST_HEAD(&op->list);
	68	spin_lock(&ops_lock);
	69	list_add_tail(&op->list, &send_list);
	70	spin_unlock(&ops_lock);
	71	wake_up(&send_wq);
	72	}
	73
901025d2 DT	74	/* If a process was killed while waiting for the only plock on a file,
	75	locks_remove_posix will not see any lock on the file so it won't
	76	send an unlock-close to us to pass on to userspace to clean up the
	77	abandoned waiter. So, we have to insert the unlock-close when the
	78	lock call is interrupted. */
	79
	80	static void do_unlock_close(struct dlm_ls *ls, u64 number,
	81	struct file file, struct file_lock fl)
	82	{
	83	struct plock_op *op;
	84
	85	op = kzalloc(sizeof(*op), GFP_NOFS);
	86	if (!op)
	87	return;
	88
	89	op->info.optype = DLM_PLOCK_OP_UNLOCK;
	90	op->info.pid = fl->fl_pid;
	91	op->info.fsid = ls->ls_global_id;
	92	op->info.number = number;
	93	op->info.start = 0;
	94	op->info.end = OFFSET_MAX;
8fb47a4f	95	if (fl->fl_lmops && fl->fl_lmops->lm_grant)
901025d2 DT	96	op->info.owner = (__u64) fl->fl_pid;
	97	else
	98	op->info.owner = (__u64)(long) fl->fl_owner;
	99
	100	op->info.flags \|= DLM_PLOCK_FL_CLOSE;
	101	send_op(op);
	102	}
	103
2402211a DT	104	int dlm_posix_lock(dlm_lockspace_t lockspace, u64 number, struct file file,
2402211a DT	105	int cmd, struct file_lock *fl)
869d81df	106	{
2402211a	107	struct dlm_ls *ls;
869d81df	108	struct plock_op *op;
586759f0	109	struct plock_xop *xop;
869d81df DT	110	int rv;
869d81df DT	111
2402211a DT	112	ls = dlm_find_lockspace_local(lockspace);
	113	if (!ls)
	114	return -EINVAL;
	115
573c24c4	116	xop = kzalloc(sizeof(*xop), GFP_NOFS);
2402211a DT	117	if (!xop) {
	118	rv = -ENOMEM;
	119	goto out;
	120	}
869d81df	121
586759f0	122	op = &xop->xop;
2402211a	123	op->info.optype = DLM_PLOCK_OP_LOCK;
3a2a9c96	124	op->info.pid = fl->fl_pid;
869d81df DT	125	op->info.ex = (fl->fl_type == F_WRLCK);
869d81df DT	126	op->info.wait = IS_SETLKW(cmd);
2402211a DT	127	op->info.fsid = ls->ls_global_id;
2402211a DT	128	op->info.number = number;
869d81df DT	129	op->info.start = fl->fl_start;
869d81df DT	130	op->info.end = fl->fl_end;
8fb47a4f	131	if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2066b58b DT	132	/* fl_owner is lockd which doesn't distinguish
	133	processes on the nfs client */
	134	op->info.owner = (__u64) fl->fl_pid;
8fb47a4f	135	xop->callback = fl->fl_lmops->lm_grant;
586759f0 ME	136	locks_init_lock(&xop->flc);
	137	locks_copy_lock(&xop->flc, fl);
	138	xop->fl = fl;
	139	xop->file = file;
2066b58b DT	140	} else {
2066b58b DT	141	op->info.owner = (__u64)(long) fl->fl_owner;
586759f0	142	xop->callback = NULL;
2066b58b	143	}
869d81df DT	144
869d81df DT	145	send_op(op);
586759f0	146
901025d2	147	if (xop->callback == NULL) {
a6b1533e	148	rv = wait_event_interruptible(recv_wq, (op->done != 0));
901025d2 DT	149	if (rv == -ERESTARTSYS) {
	150	log_debug(ls, "dlm_posix_lock: wait killed %llx",
	151	(unsigned long long)number);
	152	spin_lock(&ops_lock);
	153	list_del(&op->list);
	154	spin_unlock(&ops_lock);
	155	kfree(xop);
	156	do_unlock_close(ls, number, file, fl);
	157	goto out;
	158	}
	159	} else {
bde74e4b	160	rv = FILE_LOCK_DEFERRED;
2402211a DT	161	goto out;
2402211a DT	162	}
869d81df DT	163
	164	spin_lock(&ops_lock);
	165	if (!list_empty(&op->list)) {
2402211a DT	166	log_error(ls, "dlm_posix_lock: op on list %llx",
2402211a DT	167	(unsigned long long)number);
869d81df DT	168	list_del(&op->list);
	169	}
	170	spin_unlock(&ops_lock);
	171
	172	rv = op->info.rv;
	173
	174	if (!rv) {
4f656367	175	if (locks_lock_file_wait(file, fl) < 0)
2402211a DT	176	log_error(ls, "dlm_posix_lock: vfs lock error %llx",
2402211a DT	177	(unsigned long long)number);
869d81df DT	178	}
869d81df DT	179
586759f0	180	kfree(xop);
2402211a DT	181	out:
2402211a DT	182	dlm_put_lockspace(ls);
586759f0 ME	183	return rv;
586759f0 ME	184	}
2402211a	185	EXPORT_SYMBOL_GPL(dlm_posix_lock);
586759f0	186
af901ca1	187	/* Returns failure iff a successful lock operation should be canceled */
2402211a	188	static int dlm_plock_callback(struct plock_op *op)
586759f0 ME	189	{
	190	struct file *file;
	191	struct file_lock *fl;
	192	struct file_lock *flc;
d0449b90	193	int (notify)(struct file_lock fl, int result) = NULL;
586759f0 ME	194	struct plock_xop xop = (struct plock_xop )op;
	195	int rv = 0;
	196
	197	spin_lock(&ops_lock);
	198	if (!list_empty(&op->list)) {
2402211a DT	199	log_print("dlm_plock_callback: op on list %llx",
2402211a DT	200	(unsigned long long)op->info.number);
586759f0 ME	201	list_del(&op->list);
	202	}
	203	spin_unlock(&ops_lock);
	204
	205	/* check if the following 2 are still valid or make a copy */
	206	file = xop->file;
	207	flc = &xop->flc;
	208	fl = xop->fl;
	209	notify = xop->callback;
	210
	211	if (op->info.rv) {
d0449b90	212	notify(fl, op->info.rv);
586759f0 ME	213	goto out;
	214	}
	215
	216	/* got fs lock; bookkeep locally as well: */
	217	flc->fl_flags &= ~FL_SLEEP;
	218	if (posix_lock_file(file, flc, NULL)) {
	219	/*
	220	* This can only happen in the case of kmalloc() failure.
	221	* The filesystem's own lock is the authoritative lock,
	222	* so a failure to get the lock locally is not a disaster.
2402211a	223	* As long as the fs cannot reliably cancel locks (especially
586759f0 ME	224	* in a low-memory situation), we're better off ignoring
	225	* this failure than trying to recover.
	226	*/
2402211a DT	227	log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
2402211a DT	228	(unsigned long long)op->info.number, file, fl);
586759f0 ME	229	}
586759f0 ME	230
d0449b90	231	rv = notify(fl, 0);
586759f0 ME	232	if (rv) {
586759f0 ME	233	/* XXX: We need to cancel the fs lock here: */
2402211a DT	234	log_print("dlm_plock_callback: lock granted after lock request "
2402211a DT	235	"failed; dangling lock!\n");
586759f0 ME	236	goto out;
	237	}
	238
	239	out:
	240	kfree(xop);
869d81df DT	241	return rv;
	242	}
	243
2402211a DT	244	int dlm_posix_unlock(dlm_lockspace_t lockspace, u64 number, struct file file,
2402211a DT	245	struct file_lock *fl)
869d81df	246	{
2402211a	247	struct dlm_ls *ls;
869d81df DT	248	struct plock_op *op;
869d81df DT	249	int rv;
90008318	250	unsigned char fl_flags = fl->fl_flags;
869d81df	251
2402211a DT	252	ls = dlm_find_lockspace_local(lockspace);
	253	if (!ls)
	254	return -EINVAL;
	255
573c24c4	256	op = kzalloc(sizeof(*op), GFP_NOFS);
2402211a DT	257	if (!op) {
	258	rv = -ENOMEM;
	259	goto out;
	260	}
869d81df	261
90008318 DT	262	/* cause the vfs unlock to return ENOENT if lock is not found */
	263	fl->fl_flags \|= FL_EXISTS;
	264
4f656367	265	rv = locks_lock_file_wait(file, fl);
90008318 DT	266	if (rv == -ENOENT) {
	267	rv = 0;
	268	goto out_free;
	269	}
	270	if (rv < 0) {
	271	log_error(ls, "dlm_posix_unlock: vfs unlock error %d %llx",
	272	rv, (unsigned long long)number);
	273	}
869d81df	274
2402211a	275	op->info.optype = DLM_PLOCK_OP_UNLOCK;
3a2a9c96	276	op->info.pid = fl->fl_pid;
2402211a DT	277	op->info.fsid = ls->ls_global_id;
2402211a DT	278	op->info.number = number;
869d81df DT	279	op->info.start = fl->fl_start;
869d81df DT	280	op->info.end = fl->fl_end;
8fb47a4f	281	if (fl->fl_lmops && fl->fl_lmops->lm_grant)
2066b58b DT	282	op->info.owner = (__u64) fl->fl_pid;
	283	else
	284	op->info.owner = (__u64)(long) fl->fl_owner;
869d81df	285
901025d2 DT	286	if (fl->fl_flags & FL_CLOSE) {
	287	op->info.flags \|= DLM_PLOCK_FL_CLOSE;
	288	send_op(op);
	289	rv = 0;
	290	goto out;
	291	}
	292
869d81df DT	293	send_op(op);
	294	wait_event(recv_wq, (op->done != 0));
	295
	296	spin_lock(&ops_lock);
	297	if (!list_empty(&op->list)) {
2402211a DT	298	log_error(ls, "dlm_posix_unlock: op on list %llx",
2402211a DT	299	(unsigned long long)number);
869d81df DT	300	list_del(&op->list);
	301	}
	302	spin_unlock(&ops_lock);
	303
	304	rv = op->info.rv;
	305
586759f0 ME	306	if (rv == -ENOENT)
	307	rv = 0;
	308
90008318	309	out_free:
869d81df	310	kfree(op);
2402211a DT	311	out:
2402211a DT	312	dlm_put_lockspace(ls);
90008318	313	fl->fl_flags = fl_flags;
869d81df DT	314	return rv;
869d81df DT	315	}
2402211a	316	EXPORT_SYMBOL_GPL(dlm_posix_unlock);
869d81df	317
2402211a DT	318	int dlm_posix_get(dlm_lockspace_t lockspace, u64 number, struct file file,
2402211a DT	319	struct file_lock *fl)
869d81df	320	{
2402211a	321	struct dlm_ls *ls;
869d81df DT	322	struct plock_op *op;
	323	int rv;
	324
2402211a DT	325	ls = dlm_find_lockspace_local(lockspace);
	326	if (!ls)
	327	return -EINVAL;
	328
573c24c4	329	op = kzalloc(sizeof(*op), GFP_NOFS);
2402211a DT	330	if (!op) {
	331	rv = -ENOMEM;
	332	goto out;
	333	}
869d81df	334
2402211a	335	op->info.optype = DLM_PLOCK_OP_GET;
3a2a9c96	336	op->info.pid = fl->fl_pid;
869d81df	337	op->info.ex = (fl->fl_type == F_WRLCK);
2402211a DT	338	op->info.fsid = ls->ls_global_id;
2402211a DT	339	op->info.number = number;
869d81df DT	340	op->info.start = fl->fl_start;
869d81df DT	341	op->info.end = fl->fl_end;
8fb47a4f	342	if (fl->fl_lmops && fl->fl_lmops->lm_grant)
2066b58b DT	343	op->info.owner = (__u64) fl->fl_pid;
	344	else
	345	op->info.owner = (__u64)(long) fl->fl_owner;
586759f0	346
869d81df DT	347	send_op(op);
	348	wait_event(recv_wq, (op->done != 0));
	349
	350	spin_lock(&ops_lock);
	351	if (!list_empty(&op->list)) {
2402211a DT	352	log_error(ls, "dlm_posix_get: op on list %llx",
2402211a DT	353	(unsigned long long)number);
869d81df DT	354	list_del(&op->list);
	355	}
	356	spin_unlock(&ops_lock);
	357
a7a2ff8a DT	358	/* info.rv from userspace is 1 for conflict, 0 for no-conflict,
	359	-ENOENT if there are no locks on the file */
	360
869d81df DT	361	rv = op->info.rv;
869d81df DT	362
586759f0 ME	363	fl->fl_type = F_UNLCK;
	364	if (rv == -ENOENT)
	365	rv = 0;
a7a2ff8a	366	else if (rv > 0) {
20d5a399	367	locks_init_lock(fl);
869d81df	368	fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
20d5a399	369	fl->fl_flags = FL_POSIX;
869d81df DT	370	fl->fl_pid = op->info.pid;
	371	fl->fl_start = op->info.start;
	372	fl->fl_end = op->info.end;
a7a2ff8a	373	rv = 0;
869d81df DT	374	}
	375
	376	kfree(op);
2402211a DT	377	out:
2402211a DT	378	dlm_put_lockspace(ls);
869d81df DT	379	return rv;
869d81df DT	380	}
2402211a	381	EXPORT_SYMBOL_GPL(dlm_posix_get);
869d81df DT	382
	383	/* a read copies out one plock request from the send list */
	384	static ssize_t dev_read(struct file file, char __user u, size_t count,
	385	loff_t *ppos)
	386	{
2402211a	387	struct dlm_plock_info info;
869d81df DT	388	struct plock_op *op = NULL;
	389
	390	if (count < sizeof(info))
	391	return -EINVAL;
	392
	393	spin_lock(&ops_lock);
	394	if (!list_empty(&send_list)) {
	395	op = list_entry(send_list.next, struct plock_op, list);
901025d2 DT	396	if (op->info.flags & DLM_PLOCK_FL_CLOSE)
	397	list_del(&op->list);
	398	else
	399	list_move(&op->list, &recv_list);
869d81df DT	400	memcpy(&info, &op->info, sizeof(info));
	401	}
	402	spin_unlock(&ops_lock);
	403
	404	if (!op)
	405	return -EAGAIN;
	406
901025d2 DT	407	/* there is no need to get a reply from userspace for unlocks
	408	that were generated by the vfs cleaning up for a close
	409	(the process did not make an unlock call). */
	410
	411	if (op->info.flags & DLM_PLOCK_FL_CLOSE)
	412	kfree(op);
	413
869d81df DT	414	if (copy_to_user(u, &info, sizeof(info)))
	415	return -EFAULT;
	416	return sizeof(info);
	417	}
	418
	419	/* a write copies in one plock result that should match a plock_op
	420	on the recv list */
	421	static ssize_t dev_write(struct file file, const char __user u, size_t count,
	422	loff_t *ppos)
	423	{
2402211a	424	struct dlm_plock_info info;
869d81df	425	struct plock_op *op;
c78a87d0	426	int found = 0, do_callback = 0;
869d81df DT	427
	428	if (count != sizeof(info))
	429	return -EINVAL;
	430
	431	if (copy_from_user(&info, u, sizeof(info)))
	432	return -EFAULT;
	433
	434	if (check_version(&info))
	435	return -EINVAL;
	436
	437	spin_lock(&ops_lock);
	438	list_for_each_entry(op, &recv_list, list) {
c78a87d0 DT	439	if (op->info.fsid == info.fsid &&
c78a87d0 DT	440	op->info.number == info.number &&
08eac93a	441	op->info.owner == info.owner) {
c78a87d0	442	struct plock_xop xop = (struct plock_xop )op;
869d81df	443	list_del_init(&op->list);
869d81df	444	memcpy(&op->info, &info, sizeof(info));
c78a87d0 DT	445	if (xop->callback)
	446	do_callback = 1;
	447	else
	448	op->done = 1;
	449	found = 1;
869d81df DT	450	break;
	451	}
	452	}
	453	spin_unlock(&ops_lock);
	454
586759f0	455	if (found) {
c78a87d0	456	if (do_callback)
817d10ba	457	dlm_plock_callback(op);
586759f0 ME	458	else
	459	wake_up(&recv_wq);
	460	} else
2402211a DT	461	log_print("dev_write no op %x %llx", info.fsid,
2402211a DT	462	(unsigned long long)info.number);
869d81df DT	463	return count;
	464	}
	465
	466	static unsigned int dev_poll(struct file file, poll_table wait)
	467	{
cee23c79 DC	468	unsigned int mask = 0;
cee23c79 DC	469
869d81df DT	470	poll_wait(file, &send_wq, wait);
	471
	472	spin_lock(&ops_lock);
cee23c79 DC	473	if (!list_empty(&send_list))
cee23c79 DC	474	mask = POLLIN \| POLLRDNORM;
869d81df	475	spin_unlock(&ops_lock);
cee23c79 DC	476
cee23c79 DC	477	return mask;
869d81df DT	478	}
869d81df DT	479
00977a59	480	static const struct file_operations dev_fops = {
869d81df DT	481	.read = dev_read,
	482	.write = dev_write,
	483	.poll = dev_poll,
6038f373 AB	484	.owner = THIS_MODULE,
6038f373 AB	485	.llseek = noop_llseek,
869d81df DT	486	};
	487
	488	static struct miscdevice plock_dev_misc = {
	489	.minor = MISC_DYNAMIC_MINOR,
2402211a	490	.name = DLM_PLOCK_MISC_NAME,
869d81df DT	491	.fops = &dev_fops
	492	};
	493
2402211a	494	int dlm_plock_init(void)
869d81df DT	495	{
	496	int rv;
	497
	498	spin_lock_init(&ops_lock);
	499	INIT_LIST_HEAD(&send_list);
	500	INIT_LIST_HEAD(&recv_list);
	501	init_waitqueue_head(&send_wq);
	502	init_waitqueue_head(&recv_wq);
	503
	504	rv = misc_register(&plock_dev_misc);
	505	if (rv)
2402211a	506	log_print("dlm_plock_init: misc_register failed %d", rv);
869d81df DT	507	return rv;
	508	}
	509
2402211a	510	void dlm_plock_exit(void)
869d81df	511	{
f368ed60	512	misc_deregister(&plock_dev_misc);
869d81df DT	513	}
869d81df DT	514