alistair23-linux/fs/gfs2/sys.c
Steven Whitehouse 64d576ba23 GFS2: Add a "demote a glock" interface to sysfs
This adds a sysfs file called demote_rq to GFS2's
per filesystem directory. Its possible to use this
file to demote arbitrary glocks in exactly the same
way as if a request had come in from a remote node.

This is intended for testing issues relating to caching
of data under glocks. Despite that, the interface is
generic enough to send requests to any type of glock,
but be careful as its not always safe to send an
arbitrary message to an arbitrary glock. For that reason
and to prevent DoS, this interface is restricted to root
only.

The messages look like this:

<type>:<glocknumber> <mode>

Example:

echo -n "2:13324 EX" >/sys/fs/gfs2/unity:myfs/demote_rq

Which means "please demote inode glock (type 2) number 13324 so that
I can get an EX (exclusive) lock". The lock modes are those which
would normally be sent by a remote node in its callback so if you
want to unlock a glock, you use EX, to demote to shared, use SH or PR
(depending on whether you like GFS2 or DLM lock modes better!).

If the glock doesn't exist, you'll get -ENOENT returned. If the
arguments don't make sense, you'll get -EINVAL returned.

The plan is that this interface will be used in combination with
the blktrace patch which I recently posted for comments although
it is, of course, still useful in its own right.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-03-24 11:21:22 +00:00

708 lines
18 KiB
C

/*
* 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 <asm/uaccess.h>
#include <linux/gfs2_ondisk.h>
#include "gfs2.h"
#include "incore.h"
#include "sys.h"
#include "super.h"
#include "glock.h"
#include "quota.h"
#include "util.h"
#include "glops.h"
static ssize_t id_show(struct gfs2_sbd *sdp, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%u:%u\n",
MAJOR(sdp->sd_vfs->s_dev), MINOR(sdp->sd_vfs->s_dev));
}
static ssize_t fsname_show(struct gfs2_sbd *sdp, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%s\n", sdp->sd_fsname);
}
static int gfs2_uuid_valid(const u8 *uuid)
{
int i;
for (i = 0; i < 16; i++) {
if (uuid[i])
return 1;
}
return 0;
}
static ssize_t uuid_show(struct gfs2_sbd *sdp, char *buf)
{
const u8 *uuid = sdp->sd_sb.sb_uuid;
buf[0] = '\0';
if (!gfs2_uuid_valid(uuid))
return 0;
return snprintf(buf, PAGE_SIZE, "%02X%02X%02X%02X-%02X%02X-"
"%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X\n",
uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5],
uuid[6], uuid[7], uuid[8], uuid[9], uuid[10], uuid[11],
uuid[12], uuid[13], uuid[14], uuid[15]);
}
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 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;
}
static ssize_t demote_rq_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
struct gfs2_glock *gl;
const struct gfs2_glock_operations *glops;
unsigned int glmode;
unsigned int gltype;
unsigned long long glnum;
char mode[16];
int rv;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
rv = sscanf(buf, "%u:%llu %15s", &gltype, &glnum,
mode);
if (rv != 3)
return -EINVAL;
if (strcmp(mode, "EX") == 0)
glmode = LM_ST_UNLOCKED;
else if ((strcmp(mode, "CW") == 0) || (strcmp(mode, "DF") == 0))
glmode = LM_ST_DEFERRED;
else if ((strcmp(mode, "PR") == 0) || (strcmp(mode, "SH") == 0))
glmode = LM_ST_SHARED;
else
return -EINVAL;
if (gltype > LM_TYPE_JOURNAL)
return -EINVAL;
glops = gfs2_glops_list[gltype];
if (glops == NULL)
return -EINVAL;
rv = gfs2_glock_get(sdp, glnum, glops, 0, &gl);
if (rv)
return rv;
gfs2_glock_cb(gl, glmode);
gfs2_glock_put(gl);
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(uuid, 0444, uuid_show, NULL);
GFS2_ATTR(freeze, 0644, freeze_show, freeze_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);
GFS2_ATTR(demote_rq, 0200, NULL, demote_rq_store);
static struct attribute *gfs2_attrs[] = {
&gfs2_attr_id.attr,
&gfs2_attr_fsname.attr,
&gfs2_attr_uuid.attr,
&gfs2_attr_freeze.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,
&gfs2_attr_demote_rq.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;
/*
* 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");
static struct attribute *lockstruct_attrs[] = {
&lockstruct_attr_jid.attr,
&lockstruct_attr_first.attr,
NULL,
};
/*
* lock_module. Originally from lock_dlm
*/
static ssize_t proto_name_show(struct gfs2_sbd *sdp, char *buf)
{
const struct lm_lockops *ops = sdp->sd_lockstruct.ls_ops;
return sprintf(buf, "%s\n", ops->lm_proto_name);
}
static ssize_t block_show(struct gfs2_sbd *sdp, char *buf)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
ssize_t ret;
int val = 0;
if (test_bit(DFL_BLOCK_LOCKS, &ls->ls_flags))
val = 1;
ret = sprintf(buf, "%d\n", val);
return ret;
}
static ssize_t block_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
ssize_t ret = len;
int val;
val = simple_strtol(buf, NULL, 0);
if (val == 1)
set_bit(DFL_BLOCK_LOCKS, &ls->ls_flags);
else if (val == 0) {
clear_bit(DFL_BLOCK_LOCKS, &ls->ls_flags);
smp_mb__after_clear_bit();
gfs2_glock_thaw(sdp);
} else {
ret = -EINVAL;
}
return ret;
}
static ssize_t lkid_show(struct gfs2_sbd *sdp, char *buf)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sprintf(buf, "%u\n", ls->ls_id);
}
static ssize_t lkfirst_show(struct gfs2_sbd *sdp, char *buf)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sprintf(buf, "%d\n", ls->ls_first);
}
static ssize_t first_done_show(struct gfs2_sbd *sdp, char *buf)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sprintf(buf, "%d\n", ls->ls_first_done);
}
static ssize_t recover_show(struct gfs2_sbd *sdp, char *buf)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sprintf(buf, "%d\n", ls->ls_recover_jid);
}
static void gfs2_jdesc_make_dirty(struct gfs2_sbd *sdp, unsigned int jid)
{
struct gfs2_jdesc *jd;
spin_lock(&sdp->sd_jindex_spin);
list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
if (jd->jd_jid != jid)
continue;
jd->jd_dirty = 1;
break;
}
spin_unlock(&sdp->sd_jindex_spin);
}
static ssize_t recover_store(struct gfs2_sbd *sdp, const char *buf, size_t len)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
ls->ls_recover_jid = simple_strtol(buf, NULL, 0);
gfs2_jdesc_make_dirty(sdp, ls->ls_recover_jid);
if (sdp->sd_recoverd_process)
wake_up_process(sdp->sd_recoverd_process);
return len;
}
static ssize_t recover_done_show(struct gfs2_sbd *sdp, char *buf)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sprintf(buf, "%d\n", ls->ls_recover_jid_done);
}
static ssize_t recover_status_show(struct gfs2_sbd *sdp, char *buf)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sprintf(buf, "%d\n", ls->ls_recover_jid_status);
}
struct gdlm_attr {
struct attribute attr;
ssize_t (*show)(struct gfs2_sbd *sdp, char *);
ssize_t (*store)(struct gfs2_sbd *sdp, const char *, size_t);
};
#define GDLM_ATTR(_name,_mode,_show,_store) \
static struct gdlm_attr gdlm_attr_##_name = __ATTR(_name,_mode,_show,_store)
GDLM_ATTR(proto_name, 0444, proto_name_show, NULL);
GDLM_ATTR(block, 0644, block_show, block_store);
GDLM_ATTR(withdraw, 0644, withdraw_show, withdraw_store);
GDLM_ATTR(id, 0444, lkid_show, NULL);
GDLM_ATTR(first, 0444, lkfirst_show, NULL);
GDLM_ATTR(first_done, 0444, first_done_show, NULL);
GDLM_ATTR(recover, 0644, recover_show, recover_store);
GDLM_ATTR(recover_done, 0444, recover_done_show, NULL);
GDLM_ATTR(recover_status, 0444, recover_status_show, NULL);
static struct attribute *lock_module_attrs[] = {
&gdlm_attr_proto_name.attr,
&gdlm_attr_block.attr,
&gdlm_attr_withdraw.attr,
&gdlm_attr_id.attr,
&lockstruct_attr_jid.attr,
&gdlm_attr_first.attr,
&gdlm_attr_first_done.attr,
&gdlm_attr_recover.attr,
&gdlm_attr_recover_done.attr,
&gdlm_attr_recover_status.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(posix_acl, "%d\n");
ARGS_ATTR(quota, "%u\n");
ARGS_ATTR(suiddir, "%d\n");
ARGS_ATTR(data, "%d\n");
static struct attribute *args_attrs[] = {
&args_attr_lockproto.attr,
&args_attr_locktable.attr,
&args_attr_hostdata.attr,
&args_attr_spectator.attr,
&args_attr_ignore_local_fs.attr,
&args_attr_localcaching.attr,
&args_attr_localflocks.attr,
&args_attr_debug.attr,
&args_attr_upgrade.attr,
&args_attr_posix_acl.attr,
&args_attr_quota.attr,
&args_attr_suiddir.attr,
&args_attr_data.attr,
NULL,
};
/*
* get and set struct gfs2_tune fields
*/
static ssize_t quota_scale_show(struct gfs2_sbd *sdp, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%u %u\n",
sdp->sd_tune.gt_quota_scale_num,
sdp->sd_tune.gt_quota_scale_den);
}
static ssize_t quota_scale_store(struct gfs2_sbd *sdp, const char *buf,
size_t len)
{
struct gfs2_tune *gt = &sdp->sd_tune;
unsigned int x, y;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (sscanf(buf, "%u %u", &x, &y) != 2 || !y)
return -EINVAL;
spin_lock(&gt->gt_spin);
gt->gt_quota_scale_num = x;
gt->gt_quota_scale_den = y;
spin_unlock(&gt->gt_spin);
return len;
}
static ssize_t tune_set(struct gfs2_sbd *sdp, unsigned int *field,
int check_zero, const char *buf, size_t len)
{
struct gfs2_tune *gt = &sdp->sd_tune;
unsigned int x;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
x = simple_strtoul(buf, NULL, 0);
if (check_zero && !x)
return -EINVAL;
spin_lock(&gt->gt_spin);
*field = x;
spin_unlock(&gt->gt_spin);
return len;
}
struct tune_attr {
struct attribute attr;
ssize_t (*show)(struct gfs2_sbd *, char *);
ssize_t (*store)(struct gfs2_sbd *, const char *, size_t);
};
#define TUNE_ATTR_3(name, show, store) \
static struct tune_attr tune_attr_##name = __ATTR(name, 0644, show, store)
#define TUNE_ATTR_2(name, store) \
static ssize_t name##_show(struct gfs2_sbd *sdp, char *buf) \
{ \
return snprintf(buf, PAGE_SIZE, "%u\n", sdp->sd_tune.gt_##name); \
} \
TUNE_ATTR_3(name, name##_show, store)
#define TUNE_ATTR(name, check_zero) \
static ssize_t name##_store(struct gfs2_sbd *sdp, const char *buf, size_t len)\
{ \
return tune_set(sdp, &sdp->sd_tune.gt_##name, check_zero, buf, len); \
} \
TUNE_ATTR_2(name, name##_store)
#define TUNE_ATTR_DAEMON(name, process) \
static ssize_t name##_store(struct gfs2_sbd *sdp, const char *buf, size_t len)\
{ \
ssize_t r = tune_set(sdp, &sdp->sd_tune.gt_##name, 1, buf, len); \
wake_up_process(sdp->sd_##process); \
return r; \
} \
TUNE_ATTR_2(name, name##_store)
TUNE_ATTR(incore_log_blocks, 0);
TUNE_ATTR(log_flush_secs, 0);
TUNE_ATTR(quota_warn_period, 0);
TUNE_ATTR(quota_quantum, 0);
TUNE_ATTR(max_readahead, 0);
TUNE_ATTR(complain_secs, 0);
TUNE_ATTR(statfs_slow, 0);
TUNE_ATTR(new_files_jdata, 0);
TUNE_ATTR(quota_simul_sync, 1);
TUNE_ATTR(stall_secs, 1);
TUNE_ATTR(statfs_quantum, 1);
TUNE_ATTR_DAEMON(recoverd_secs, recoverd_process);
TUNE_ATTR_DAEMON(logd_secs, logd_process);
TUNE_ATTR_3(quota_scale, quota_scale_show, quota_scale_store);
static struct attribute *tune_attrs[] = {
&tune_attr_incore_log_blocks.attr,
&tune_attr_log_flush_secs.attr,
&tune_attr_quota_warn_period.attr,
&tune_attr_quota_quantum.attr,
&tune_attr_max_readahead.attr,
&tune_attr_complain_secs.attr,
&tune_attr_statfs_slow.attr,
&tune_attr_quota_simul_sync.attr,
&tune_attr_stall_secs.attr,
&tune_attr_statfs_quantum.attr,
&tune_attr_recoverd_secs.attr,
&tune_attr_logd_secs.attr,
&tune_attr_quota_scale.attr,
&tune_attr_new_files_jdata.attr,
NULL,
};
static struct attribute_group lockstruct_group = {
.name = "lockstruct",
.attrs = lockstruct_attrs,
};
static struct attribute_group args_group = {
.name = "args",
.attrs = args_attrs,
};
static struct attribute_group tune_group = {
.name = "tune",
.attrs = tune_attrs,
};
static struct attribute_group lock_module_group = {
.name = "lock_module",
.attrs = lock_module_attrs,
};
int gfs2_sys_fs_add(struct gfs2_sbd *sdp)
{
int error;
sdp->sd_kobj.kset = gfs2_kset;
error = kobject_init_and_add(&sdp->sd_kobj, &gfs2_ktype, NULL,
"%s", sdp->sd_table_name);
if (error)
goto fail;
error = sysfs_create_group(&sdp->sd_kobj, &lockstruct_group);
if (error)
goto fail_reg;
error = sysfs_create_group(&sdp->sd_kobj, &args_group);
if (error)
goto fail_lockstruct;
error = sysfs_create_group(&sdp->sd_kobj, &tune_group);
if (error)
goto fail_args;
error = sysfs_create_group(&sdp->sd_kobj, &lock_module_group);
if (error)
goto fail_tune;
kobject_uevent(&sdp->sd_kobj, KOBJ_ADD);
return 0;
fail_tune:
sysfs_remove_group(&sdp->sd_kobj, &tune_group);
fail_args:
sysfs_remove_group(&sdp->sd_kobj, &args_group);
fail_lockstruct:
sysfs_remove_group(&sdp->sd_kobj, &lockstruct_group);
fail_reg:
kobject_put(&sdp->sd_kobj);
fail:
fs_err(sdp, "error %d adding sysfs files", error);
return error;
}
void gfs2_sys_fs_del(struct gfs2_sbd *sdp)
{
sysfs_remove_group(&sdp->sd_kobj, &tune_group);
sysfs_remove_group(&sdp->sd_kobj, &args_group);
sysfs_remove_group(&sdp->sd_kobj, &lockstruct_group);
sysfs_remove_group(&sdp->sd_kobj, &lock_module_group);
kobject_put(&sdp->sd_kobj);
}
static int gfs2_uevent(struct kset *kset, struct kobject *kobj,
struct kobj_uevent_env *env)
{
struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
const u8 *uuid = sdp->sd_sb.sb_uuid;
add_uevent_var(env, "LOCKTABLE=%s", sdp->sd_table_name);
add_uevent_var(env, "LOCKPROTO=%s", sdp->sd_proto_name);
if (gfs2_uuid_valid(uuid)) {
add_uevent_var(env, "UUID=%02X%02X%02X%02X-%02X%02X-%02X%02X-"
"%02X%02X-%02X%02X%02X%02X%02X%02X",
uuid[0], uuid[1], uuid[2], uuid[3], uuid[4],
uuid[5], uuid[6], uuid[7], uuid[8], uuid[9],
uuid[10], uuid[11], uuid[12], uuid[13],
uuid[14], uuid[15]);
}
return 0;
}
static struct kset_uevent_ops gfs2_uevent_ops = {
.uevent = gfs2_uevent,
};
int gfs2_sys_init(void)
{
gfs2_kset = kset_create_and_add("gfs2", &gfs2_uevent_ops, fs_kobj);
if (!gfs2_kset)
return -ENOMEM;
return 0;
}
void gfs2_sys_uninit(void)
{
kset_unregister(gfs2_kset);
}