sys.c

linux 内核源代码

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 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/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>
#include <asm/uaccess.h>

#include "gfs2.h"
#include "incore.h"
#include "lm.h"
#include "sys.h"
#include "super.h"
#include "glock.h"
#include "quota.h"
#include "util.h"

char *gfs2_sys_margs;
spinlock_t gfs2_sys_margs_lock;

static ssize_t id_show(struct gfs2_sbd *sdp, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%s\n", sdp->sd_vfs->s_id);
}

static ssize_t fsname_show(struct gfs2_sbd *sdp, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%s\n", sdp->sd_fsname);
}

static ssize_t freeze_show(struct gfs2_sbd *sdp, char *buf)
{
	unsigned int count;

	mutex_lock(&sdp->sd_freeze_lock);
	count = sdp->sd_freeze_count;
	mutex_unlock(&sdp->sd_freeze_lock);

	return snprintf(buf, PAGE_SIZE, "%u\n", count);
}

static ssize_t freeze_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
	ssize_t ret = len;
	int error = 0;
	int n = simple_strtol(buf, NULL, 0);

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	switch (n) {
	case 0:
		gfs2_unfreeze_fs(sdp);
		break;
	case 1:
		error = gfs2_freeze_fs(sdp);
		break;
	default:
		ret = -EINVAL;
	}

	if (error)
		fs_warn(sdp, "freeze %d error %d", n, error);

	return ret;
}

static ssize_t withdraw_show(struct gfs2_sbd *sdp, char *buf)
{
	unsigned int b = test_bit(SDF_SHUTDOWN, &sdp->sd_flags);
	return snprintf(buf, PAGE_SIZE, "%u\n", b);
}

static ssize_t withdraw_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (simple_strtol(buf, NULL, 0) != 1)
		return -EINVAL;

	gfs2_lm_withdraw(sdp,
		"GFS2: fsid=%s: withdrawing from cluster at user's request\n",
		sdp->sd_fsname);
	return len;
}

static ssize_t statfs_sync_store(struct gfs2_sbd *sdp, const char *buf,
				 size_t len)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (simple_strtol(buf, NULL, 0) != 1)
		return -EINVAL;

	gfs2_statfs_sync(sdp);
	return len;
}

static ssize_t shrink_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (simple_strtol(buf, NULL, 0) != 1)
		return -EINVAL;

	gfs2_gl_hash_clear(sdp, NO_WAIT);
	return len;
}

static ssize_t quota_sync_store(struct gfs2_sbd *sdp, const char *buf,
				size_t len)
{
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (simple_strtol(buf, NULL, 0) != 1)
		return -EINVAL;

	gfs2_quota_sync(sdp);
	return len;
}

static ssize_t quota_refresh_user_store(struct gfs2_sbd *sdp, const char *buf,
					size_t len)
{
	u32 id;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	id = simple_strtoul(buf, NULL, 0);

	gfs2_quota_refresh(sdp, 1, id);
	return len;
}

static ssize_t quota_refresh_group_store(struct gfs2_sbd *sdp, const char *buf,
					 size_t len)
{
	u32 id;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	id = simple_strtoul(buf, NULL, 0);

	gfs2_quota_refresh(sdp, 0, id);
	return len;
}

struct gfs2_attr {
	struct attribute attr;
	ssize_t (*show)(struct gfs2_sbd *, char *);
	ssize_t (*store)(struct gfs2_sbd *, const char *, size_t);
};

#define GFS2_ATTR(name, mode, show, store) \
static struct gfs2_attr gfs2_attr_##name = __ATTR(name, mode, show, store)

GFS2_ATTR(id,                  0444, id_show,       NULL);
GFS2_ATTR(fsname,              0444, fsname_show,   NULL);
GFS2_ATTR(freeze,              0644, freeze_show,   freeze_store);
GFS2_ATTR(shrink,              0200, NULL,          shrink_store);
GFS2_ATTR(withdraw,            0644, withdraw_show, withdraw_store);
GFS2_ATTR(statfs_sync,         0200, NULL,          statfs_sync_store);
GFS2_ATTR(quota_sync,          0200, NULL,          quota_sync_store);
GFS2_ATTR(quota_refresh_user,  0200, NULL,          quota_refresh_user_store);
GFS2_ATTR(quota_refresh_group, 0200, NULL,          quota_refresh_group_store);

static struct attribute *gfs2_attrs[] = {
	&gfs2_attr_id.attr,
	&gfs2_attr_fsname.attr,
	&gfs2_attr_freeze.attr,
	&gfs2_attr_shrink.attr,
	&gfs2_attr_withdraw.attr,
	&gfs2_attr_statfs_sync.attr,
	&gfs2_attr_quota_sync.attr,
	&gfs2_attr_quota_refresh_user.attr,
	&gfs2_attr_quota_refresh_group.attr,
	NULL,
};

static ssize_t gfs2_attr_show(struct kobject *kobj, struct attribute *attr,
			      char *buf)
{
	struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
	struct gfs2_attr *a = container_of(attr, struct gfs2_attr, attr);
	return a->show ? a->show(sdp, buf) : 0;
}

static ssize_t gfs2_attr_store(struct kobject *kobj, struct attribute *attr,
			       const char *buf, size_t len)
{
	struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
	struct gfs2_attr *a = container_of(attr, struct gfs2_attr, attr);
	return a->store ? a->store(sdp, buf, len) : len;
}

static struct sysfs_ops gfs2_attr_ops = {
	.show  = gfs2_attr_show,
	.store = gfs2_attr_store,
};

static struct kobj_type gfs2_ktype = {
	.default_attrs = gfs2_attrs,
	.sysfs_ops     = &gfs2_attr_ops,
};

static struct kset gfs2_kset = {
	.ktype  = &gfs2_ktype,
};

/*
 * display struct lm_lockstruct fields
 */

struct lockstruct_attr {
	struct attribute attr;
	ssize_t (*show)(struct gfs2_sbd *, char *);
};

#define LOCKSTRUCT_ATTR(name, fmt)                                          \
static ssize_t name##_show(struct gfs2_sbd *sdp, char *buf)                 \
{                                                                           \
	return snprintf(buf, PAGE_SIZE, fmt, sdp->sd_lockstruct.ls_##name); \
}                                                                           \
static struct lockstruct_attr lockstruct_attr_##name = __ATTR_RO(name)

LOCKSTRUCT_ATTR(jid,      "%u\n");
LOCKSTRUCT_ATTR(first,    "%u\n");
LOCKSTRUCT_ATTR(lvb_size, "%u\n");
LOCKSTRUCT_ATTR(flags,    "%d\n");

static struct attribute *lockstruct_attrs[] = {
	&lockstruct_attr_jid.attr,
	&lockstruct_attr_first.attr,
	&lockstruct_attr_lvb_size.attr,
	&lockstruct_attr_flags.attr,
	NULL,
};

/*
 * display struct gfs2_args fields
 */

struct args_attr {
	struct attribute attr;
	ssize_t (*show)(struct gfs2_sbd *, char *);
};

#define ARGS_ATTR(name, fmt)                                                \
static ssize_t name##_show(struct gfs2_sbd *sdp, char *buf)                 \
{                                                                           \
	return snprintf(buf, PAGE_SIZE, fmt, sdp->sd_args.ar_##name);       \
}                                                                           \
static struct args_attr args_attr_##name = __ATTR_RO(name)

ARGS_ATTR(lockproto,       "%s\n");
ARGS_ATTR(locktable,       "%s\n");
ARGS_ATTR(hostdata,        "%s\n");
ARGS_ATTR(spectator,       "%d\n");
ARGS_ATTR(ignore_local_fs, "%d\n");
ARGS_ATTR(localcaching,    "%d\n");
ARGS_ATTR(localflocks,     "%d\n");
ARGS_ATTR(debug,           "%d\n");
ARGS_ATTR(upgrade,         "%d\n");
ARGS_ATTR(num_glockd,      "%u\n");