lockspace.c

linux 内核源代码

/******************************************************************************
*******************************************************************************
**
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2004-2007 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 "dlm_internal.h"
#include "lockspace.h"
#include "member.h"
#include "recoverd.h"
#include "ast.h"
#include "dir.h"
#include "lowcomms.h"
#include "config.h"
#include "memory.h"
#include "lock.h"
#include "recover.h"
#include "requestqueue.h"

#ifdef CONFIG_DLM_DEBUG
int dlm_create_debug_file(struct dlm_ls *ls);
void dlm_delete_debug_file(struct dlm_ls *ls);
#else
static inline int dlm_create_debug_file(struct dlm_ls *ls) { return 0; }
static inline void dlm_delete_debug_file(struct dlm_ls *ls) { }
#endif

static int			ls_count;
static struct mutex		ls_lock;
static struct list_head		lslist;
static spinlock_t		lslist_lock;
static struct task_struct *	scand_task;


static ssize_t dlm_control_store(struct dlm_ls *ls, const char *buf, size_t len)
{
	ssize_t ret = len;
	int n = simple_strtol(buf, NULL, 0);

	ls = dlm_find_lockspace_local(ls->ls_local_handle);
	if (!ls)
		return -EINVAL;

	switch (n) {
	case 0:
		dlm_ls_stop(ls);
		break;
	case 1:
		dlm_ls_start(ls);
		break;
	default:
		ret = -EINVAL;
	}
	dlm_put_lockspace(ls);
	return ret;
}

static ssize_t dlm_event_store(struct dlm_ls *ls, const char *buf, size_t len)
{
	ls->ls_uevent_result = simple_strtol(buf, NULL, 0);
	set_bit(LSFL_UEVENT_WAIT, &ls->ls_flags);
	wake_up(&ls->ls_uevent_wait);
	return len;
}

static ssize_t dlm_id_show(struct dlm_ls *ls, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%u\n", ls->ls_global_id);
}

static ssize_t dlm_id_store(struct dlm_ls *ls, const char *buf, size_t len)
{
	ls->ls_global_id = simple_strtoul(buf, NULL, 0);
	return len;
}

static ssize_t dlm_recover_status_show(struct dlm_ls *ls, char *buf)
{
	uint32_t status = dlm_recover_status(ls);
	return snprintf(buf, PAGE_SIZE, "%x\n", status);
}

static ssize_t dlm_recover_nodeid_show(struct dlm_ls *ls, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%d\n", ls->ls_recover_nodeid);
}

struct dlm_attr {
	struct attribute attr;
	ssize_t (*show)(struct dlm_ls *, char *);
	ssize_t (*store)(struct dlm_ls *, const char *, size_t);
};

static struct dlm_attr dlm_attr_control = {
	.attr  = {.name = "control", .mode = S_IWUSR},
	.store = dlm_control_store
};

static struct dlm_attr dlm_attr_event = {
	.attr  = {.name = "event_done", .mode = S_IWUSR},
	.store = dlm_event_store
};

static struct dlm_attr dlm_attr_id = {
	.attr  = {.name = "id", .mode = S_IRUGO | S_IWUSR},
	.show  = dlm_id_show,
	.store = dlm_id_store
};

static struct dlm_attr dlm_attr_recover_status = {
	.attr  = {.name = "recover_status", .mode = S_IRUGO},
	.show  = dlm_recover_status_show
};

static struct dlm_attr dlm_attr_recover_nodeid = {
	.attr  = {.name = "recover_nodeid", .mode = S_IRUGO},
	.show  = dlm_recover_nodeid_show
};

static struct attribute *dlm_attrs[] = {
	&dlm_attr_control.attr,
	&dlm_attr_event.attr,
	&dlm_attr_id.attr,
	&dlm_attr_recover_status.attr,
	&dlm_attr_recover_nodeid.attr,
	NULL,
};

static ssize_t dlm_attr_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
{
	struct dlm_ls *ls  = container_of(kobj, struct dlm_ls, ls_kobj);
	struct dlm_attr *a = container_of(attr, struct dlm_attr, attr);
	return a->show ? a->show(ls, buf) : 0;
}

static ssize_t dlm_attr_store(struct kobject *kobj, struct attribute *attr,
			      const char *buf, size_t len)
{
	struct dlm_ls *ls  = container_of(kobj, struct dlm_ls, ls_kobj);
	struct dlm_attr *a = container_of(attr, struct dlm_attr, attr);
	return a->store ? a->store(ls, buf, len) : len;
}

static void lockspace_kobj_release(struct kobject *k)
{
	struct dlm_ls *ls  = container_of(k, struct dlm_ls, ls_kobj);
	kfree(ls);
}

static struct sysfs_ops dlm_attr_ops = {
	.show  = dlm_attr_show,
	.store = dlm_attr_store,
};

static struct kobj_type dlm_ktype = {
	.default_attrs = dlm_attrs,
	.sysfs_ops     = &dlm_attr_ops,
	.release       = lockspace_kobj_release,
};

static struct kset dlm_kset = {
	.ktype  = &dlm_ktype,
};

static int kobject_setup(struct dlm_ls *ls)
{
	char lsname[DLM_LOCKSPACE_LEN];
	int error;

	memset(lsname, 0, DLM_LOCKSPACE_LEN);
	snprintf(lsname, DLM_LOCKSPACE_LEN, "%s", ls->ls_name);

	error = kobject_set_name(&ls->ls_kobj, "%s", lsname);
	if (error)
		return error;

	ls->ls_kobj.kset = &dlm_kset;
	ls->ls_kobj.ktype = &dlm_ktype;
	return 0;
}

static int do_uevent(struct dlm_ls *ls, int in)
{
	int error;

	if (in)
		kobject_uevent(&ls->ls_kobj, KOBJ_ONLINE);
	else
		kobject_uevent(&ls->ls_kobj, KOBJ_OFFLINE);

	log_debug(ls, "%s the lockspace group...", in ? "joining" : "leaving");

	/* dlm_controld will see the uevent, do the necessary group management
	   and then write to sysfs to wake us */

	error = wait_event_interruptible(ls->ls_uevent_wait,
			test_and_clear_bit(LSFL_UEVENT_WAIT, &ls->ls_flags));

	log_debug(ls, "group event done %d %d", error, ls->ls_uevent_result);

	if (error)
		goto out;

	error = ls->ls_uevent_result;
 out:
	if (error)
		log_error(ls, "group %s failed %d %d", in ? "join" : "leave",
			  error, ls->ls_uevent_result);
	return error;
}


int dlm_lockspace_init(void)
{
	int error;

	ls_count = 0;
	mutex_init(&ls_lock);
	INIT_LIST_HEAD(&lslist);
	spin_lock_init(&lslist_lock);

	kobject_set_name(&dlm_kset.kobj, "dlm");
	kobj_set_kset_s(&dlm_kset, kernel_subsys);
	error = kset_register(&dlm_kset);
	if (error)
		printk("dlm_lockspace_init: cannot register kset %d\n", error);
	return error;
}

void dlm_lockspace_exit(void)
{
	kset_unregister(&dlm_kset);
}

static int dlm_scand(void *data)
{
	struct dlm_ls *ls;

	while (!kthread_should_stop()) {
		list_for_each_entry(ls, &lslist, ls_list) {
			if (dlm_lock_recovery_try(ls)) {
				dlm_scan_rsbs(ls);
				dlm_scan_timeout(ls);
				dlm_unlock_recovery(ls);
			}
		}
		schedule_timeout_interruptible(dlm_config.ci_scan_secs * HZ);
	}
	return 0;
}

static int dlm_scand_start(void)
{
	struct task_struct *p;
	int error = 0;

	p = kthread_run(dlm_scand, NULL, "dlm_scand");
	if (IS_ERR(p))
		error = PTR_ERR(p);
	else
		scand_task = p;
	return error;
}

static void dlm_scand_stop(void)
{
	kthread_stop(scand_task);
}

static struct dlm_ls *dlm_find_lockspace_name(char *name, int namelen)
{
	struct dlm_ls *ls;

	spin_lock(&lslist_lock);

	list_for_each_entry(ls, &lslist, ls_list) {
		if (ls->ls_namelen == namelen &&
		    memcmp(ls->ls_name, name, namelen) == 0)
			goto out;
	}
	ls = NULL;
 out:
	spin_unlock(&lslist_lock);
	return ls;
}

struct dlm_ls *dlm_find_lockspace_global(uint32_t id)
{
	struct dlm_ls *ls;

	spin_lock(&lslist_lock);

	list_for_each_entry(ls, &lslist, ls_list) {
		if (ls->ls_global_id == id) {
			ls->ls_count++;
			goto out;
		}
	}
	ls = NULL;
 out:
	spin_unlock(&lslist_lock);
	return ls;
}

struct dlm_ls *dlm_find_lockspace_local(dlm_lockspace_t *lockspace)
{
	struct dlm_ls *ls;

	spin_lock(&lslist_lock);
	list_for_each_entry(ls, &lslist, ls_list) {
		if (ls->ls_local_handle == lockspace) {
			ls->ls_count++;
			goto out;
		}
	}
	ls = NULL;
 out:
	spin_unlock(&lslist_lock);
	return ls;
}

struct dlm_ls *dlm_find_lockspace_device(int minor)
{
	struct dlm_ls *ls;

	spin_lock(&lslist_lock);
	list_for_each_entry(ls, &lslist, ls_list) {
		if (ls->ls_device.minor == minor) {
			ls->ls_count++;
			goto out;
		}
	}
	ls = NULL;
 out:
	spin_unlock(&lslist_lock);
	return ls;
}

void dlm_put_lockspace(struct dlm_ls *ls)
{
	spin_lock(&lslist_lock);
	ls->ls_count--;
	spin_unlock(&lslist_lock);
}

static void remove_lockspace(struct dlm_ls *ls)
{
	for (;;) {
		spin_lock(&lslist_lock);
		if (ls->ls_count == 0) {
			list_del(&ls->ls_list);
			spin_unlock(&lslist_lock);
			return;
		}
		spin_unlock(&lslist_lock);
		ssleep(1);
	}
}

static int threads_start(void)
{
	int error;

	/* Thread which process lock requests for all lockspace's */
	error = dlm_astd_start();
	if (error) {
		log_print("cannot start dlm_astd thread %d", error);
		goto fail;
	}

	error = dlm_scand_start();
	if (error) {
		log_print("cannot start dlm_scand thread %d", error);
		goto astd_fail;
	}

	/* Thread for sending/receiving messages for all lockspace's */
	error = dlm_lowcomms_start();
	if (error) {
		log_print("cannot start dlm lowcomms %d", error);
		goto scand_fail;
	}

	return 0;

 scand_fail:
	dlm_scand_stop();
 astd_fail: