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/*
* 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 v.2.
*/
#include <linux/miscdevice.h>
#include <linux/lock_dlm_plock.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(lm_lockspace_t *lockspace, struct lm_lockname *name,
struct file *file, int cmd, struct file_lock *fl)
{
struct gdlm_ls *ls = (struct gdlm_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;
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, name->ln_number);
}
kfree(op);
return rv;
}
int gdlm_punlock(lm_lockspace_t *lockspace, struct lm_lockname *name,
struct file *file, struct file_lock *fl)
{
struct gdlm_ls *ls = (struct gdlm_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, 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;
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(lm_lockspace_t *lockspace, struct lm_lockname *name,
struct file *file, struct file_lock *fl)
{
struct gdlm_ls *ls = (struct gdlm_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) {
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,
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");
}
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