[linux-block.git] / fs / fuse / control.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include "fuse_i.h"

#include <linux/init.h>
#include <linux/module.h>

#define FUSE_CTL_SUPER_MAGIC 0x65735543

/*
 * This is non-NULL when the single instance of the control filesystem
 * exists.  Protected by fuse_mutex
 */
static struct super_block *fuse_control_sb;

static struct fuse_conn *fuse_ctl_file_conn_get(struct file *file)
{
	struct fuse_conn *fc;
	mutex_lock(&fuse_mutex);
	fc = file_inode(file)->i_private;
	if (fc)
		fc = fuse_conn_get(fc);
	mutex_unlock(&fuse_mutex);
	return fc;
}

static ssize_t fuse_conn_abort_write(struct file *file, const char __user *buf,
				     size_t count, loff_t *ppos)
{
	struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
	if (fc) {
		fuse_abort_conn(fc, true);
		fuse_conn_put(fc);
	}
	return count;
}

static ssize_t fuse_conn_waiting_read(struct file *file, char __user *buf,
				      size_t len, loff_t *ppos)
{
	char tmp[32];
	size_t size;

	if (!*ppos) {
		long value;
		struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
		if (!fc)
			return 0;

		value = atomic_read(&fc->num_waiting);
		file->private_data = (void *)value;
		fuse_conn_put(fc);
	}
	size = sprintf(tmp, "%ld\n", (long)file->private_data);
	return simple_read_from_buffer(buf, len, ppos, tmp, size);
}

static ssize_t fuse_conn_limit_read(struct file *file, char __user *buf,
				    size_t len, loff_t *ppos, unsigned val)
{
	char tmp[32];
	size_t size = sprintf(tmp, "%u\n", val);

	return simple_read_from_buffer(buf, len, ppos, tmp, size);
}

static ssize_t fuse_conn_limit_write(struct file *file, const char __user *buf,
				     size_t count, loff_t *ppos, unsigned *val,
				     unsigned global_limit)
{
	unsigned long t;
	unsigned limit = (1 << 16) - 1;
	int err;

	if (*ppos)
		return -EINVAL;

	err = kstrtoul_from_user(buf, count, 0, &t);
	if (err)
		return err;

	if (!capable(CAP_SYS_ADMIN))
		limit = min(limit, global_limit);

	if (t > limit)
		return -EINVAL;

	*val = t;

	return count;
}

static ssize_t fuse_conn_max_background_read(struct file *file,
					     char __user *buf, size_t len,
					     loff_t *ppos)
{
	struct fuse_conn *fc;
	unsigned val;

	fc = fuse_ctl_file_conn_get(file);
	if (!fc)
		return 0;

	val = READ_ONCE(fc->max_background);
	fuse_conn_put(fc);

	return fuse_conn_limit_read(file, buf, len, ppos, val);
}

static ssize_t fuse_conn_max_background_write(struct file *file,
					      const char __user *buf,
					      size_t count, loff_t *ppos)
{
	unsigned uninitialized_var(val);
	ssize_t ret;

	ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
				    max_user_bgreq);
	if (ret > 0) {
		struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
		if (fc) {
			spin_lock(&fc->bg_lock);
			fc->max_background = val;
			fc->blocked = fc->num_background >= fc->max_background;
			if (!fc->blocked)
				wake_up(&fc->blocked_waitq);
			spin_unlock(&fc->bg_lock);
			fuse_conn_put(fc);
		}
	}

	return ret;
}

static ssize_t fuse_conn_congestion_threshold_read(struct file *file,
						   char __user *buf, size_t len,
						   loff_t *ppos)
{
	struct fuse_conn *fc;
	unsigned val;

	fc = fuse_ctl_file_conn_get(file);
	if (!fc)
		return 0;

	val = READ_ONCE(fc->congestion_threshold);
	fuse_conn_put(fc);

	return fuse_conn_limit_read(file, buf, len, ppos, val);
}

static ssize_t fuse_conn_congestion_threshold_write(struct file *file,
						    const char __user *buf,
						    size_t count, loff_t *ppos)
{
	unsigned uninitialized_var(val);
	struct fuse_conn *fc;
	ssize_t ret;

	ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
				    max_user_congthresh);
	if (ret <= 0)
		goto out;
	fc = fuse_ctl_file_conn_get(file);
	if (!fc)
		goto out;

	spin_lock(&fc->bg_lock);
	fc->congestion_threshold = val;
	if (fc->sb) {
		if (fc->num_background < fc->congestion_threshold) {
			clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
			clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
		} else {
			set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
			set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
		}
	}
	spin_unlock(&fc->bg_lock);
	fuse_conn_put(fc);
out:
	return ret;
}

static const struct file_operations fuse_ctl_abort_ops = {
	.open = nonseekable_open,
	.write = fuse_conn_abort_write,
	.llseek = no_llseek,
};

static const struct file_operations fuse_ctl_waiting_ops = {
	.open = nonseekable_open,
	.read = fuse_conn_waiting_read,
	.llseek = no_llseek,
};

static const struct file_operations fuse_conn_max_background_ops = {
	.open = nonseekable_open,
	.read = fuse_conn_max_background_read,
	.write = fuse_conn_max_background_write,
	.llseek = no_llseek,
};

static const struct file_operations fuse_conn_congestion_threshold_ops = {
	.open = nonseekable_open,
	.read = fuse_conn_congestion_threshold_read,
	.write = fuse_conn_congestion_threshold_write,
	.llseek = no_llseek,
};

static struct dentry *fuse_ctl_add_dentry(struct dentry *parent,
					  struct fuse_conn *fc,
					  const char *name,
					  int mode, int nlink,
					  const struct inode_operations *iop,
					  const struct file_operations *fop)
{
	struct dentry *dentry;
	struct inode *inode;

	BUG_ON(fc->ctl_ndents >= FUSE_CTL_NUM_DENTRIES);
	dentry = d_alloc_name(parent, name);
	if (!dentry)
		return NULL;

	inode = new_inode(fuse_control_sb);
	if (!inode) {
		dput(dentry);
		return NULL;
	}

	inode->i_ino = get_next_ino();
	inode->i_mode = mode;
	inode->i_uid = fc->user_id;
	inode->i_gid = fc->group_id;
	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
	/* setting ->i_op to NULL is not allowed */
	if (iop)
		inode->i_op = iop;
	inode->i_fop = fop;
	set_nlink(inode, nlink);
	inode->i_private = fc;
	d_add(dentry, inode);

	fc->ctl_dentry[fc->ctl_ndents++] = dentry;

	return dentry;
}

/*
 * Add a connection to the control filesystem (if it exists).  Caller
 * must hold fuse_mutex
 */
int fuse_ctl_add_conn(struct fuse_conn *fc)
{
	struct dentry *parent;
	char name[32];

	if (!fuse_control_sb)
		return 0;

	parent = fuse_control_sb->s_root;
	inc_nlink(d_inode(parent));
	sprintf(name, "%u", fc->dev);
	parent = fuse_ctl_add_dentry(parent, fc, name, S_IFDIR | 0500, 2,
				     &simple_dir_inode_operations,
				     &simple_dir_operations);
	if (!parent)
		goto err;

	if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG | 0400, 1,
				 NULL, &fuse_ctl_waiting_ops) ||
	    !fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG | 0200, 1,
				 NULL, &fuse_ctl_abort_ops) ||
	    !fuse_ctl_add_dentry(parent, fc, "max_background", S_IFREG | 0600,
				 1, NULL, &fuse_conn_max_background_ops) ||
	    !fuse_ctl_add_dentry(parent, fc, "congestion_threshold",
				 S_IFREG | 0600, 1, NULL,
				 &fuse_conn_congestion_threshold_ops))
		goto err;

	return 0;

 err:
	fuse_ctl_remove_conn(fc);
	return -ENOMEM;
}

/*
 * Remove a connection from the control filesystem (if it exists).
 * Caller must hold fuse_mutex
 */
void fuse_ctl_remove_conn(struct fuse_conn *fc)
{
	int i;

	if (!fuse_control_sb)
		return;

	for (i = fc->ctl_ndents - 1; i >= 0; i--) {
		struct dentry *dentry = fc->ctl_dentry[i];
		d_inode(dentry)->i_private = NULL;
		if (!i) {
			/* Get rid of submounts: */
			d_invalidate(dentry);
		}
		dput(dentry);
	}
	drop_nlink(d_inode(fuse_control_sb->s_root));
}

static int fuse_ctl_fill_super(struct super_block *sb, void *data, int silent)
{
	static const struct tree_descr empty_descr = {""};
	struct fuse_conn *fc;
	int err;

	err = simple_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr);
	if (err)
		return err;

	mutex_lock(&fuse_mutex);
	BUG_ON(fuse_control_sb);
	fuse_control_sb = sb;
	list_for_each_entry(fc, &fuse_conn_list, entry) {
		err = fuse_ctl_add_conn(fc);
		if (err) {
			fuse_control_sb = NULL;
			mutex_unlock(&fuse_mutex);
			return err;
		}
	}
	mutex_unlock(&fuse_mutex);

	return 0;
}

static struct dentry *fuse_ctl_mount(struct file_system_type *fs_type,
			int flags, const char *dev_name, void *raw_data)
{
	return mount_single(fs_type, flags, raw_data, fuse_ctl_fill_super);
}

static void fuse_ctl_kill_sb(struct super_block *sb)
{
	struct fuse_conn *fc;

	mutex_lock(&fuse_mutex);
	fuse_control_sb = NULL;
	list_for_each_entry(fc, &fuse_conn_list, entry)
		fc->ctl_ndents = 0;
	mutex_unlock(&fuse_mutex);

	kill_litter_super(sb);
}

static struct file_system_type fuse_ctl_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fusectl",
	.mount		= fuse_ctl_mount,
	.kill_sb	= fuse_ctl_kill_sb,
};
MODULE_ALIAS_FS("fusectl");

int __init fuse_ctl_init(void)
{
	return register_filesystem(&fuse_ctl_fs_type);
}

void __exit fuse_ctl_cleanup(void)
{
	unregister_filesystem(&fuse_ctl_fs_type);
}
Commit	Line	Data
bafa9654 MS	1	/*
bafa9654 MS	2	FUSE: Filesystem in Userspace
1729a16c	3	Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
bafa9654 MS	4
	5	This program can be distributed under the terms of the GNU GPL.
	6	See the file COPYING.
	7	*/
	8
	9	#include "fuse_i.h"
	10
	11	#include <linux/init.h>
	12	#include <linux/module.h>
	13
	14	#define FUSE_CTL_SUPER_MAGIC 0x65735543
	15
	16	/*
	17	* This is non-NULL when the single instance of the control filesystem
	18	* exists. Protected by fuse_mutex
	19	*/
	20	static struct super_block *fuse_control_sb;
	21
	22	static struct fuse_conn fuse_ctl_file_conn_get(struct file file)
	23	{
	24	struct fuse_conn *fc;
	25	mutex_lock(&fuse_mutex);
496ad9aa	26	fc = file_inode(file)->i_private;
bafa9654 MS	27	if (fc)
	28	fc = fuse_conn_get(fc);
	29	mutex_unlock(&fuse_mutex);
	30	return fc;
	31	}
	32
	33	static ssize_t fuse_conn_abort_write(struct file file, const char __user buf,
	34	size_t count, loff_t *ppos)
	35	{
	36	struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
	37	if (fc) {
3b7008b2	38	fuse_abort_conn(fc, true);
bafa9654 MS	39	fuse_conn_put(fc);
	40	}
	41	return count;
	42	}
	43
	44	static ssize_t fuse_conn_waiting_read(struct file file, char __user buf,
	45	size_t len, loff_t *ppos)
	46	{
	47	char tmp[32];
	48	size_t size;
	49
	50	if (!*ppos) {
1729a16c	51	long value;
bafa9654 MS	52	struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
	53	if (!fc)
	54	return 0;
	55
1729a16c MS	56	value = atomic_read(&fc->num_waiting);
1729a16c MS	57	file->private_data = (void *)value;
bafa9654 MS	58	fuse_conn_put(fc);
	59	}
	60	size = sprintf(tmp, "%ld\n", (long)file->private_data);
	61	return simple_read_from_buffer(buf, len, ppos, tmp, size);
	62	}
	63
79a9d994 CH	64	static ssize_t fuse_conn_limit_read(struct file file, char __user buf,
	65	size_t len, loff_t *ppos, unsigned val)
	66	{
	67	char tmp[32];
	68	size_t size = sprintf(tmp, "%u\n", val);
	69
	70	return simple_read_from_buffer(buf, len, ppos, tmp, size);
	71	}
	72
	73	static ssize_t fuse_conn_limit_write(struct file file, const char __user buf,
	74	size_t count, loff_t ppos, unsigned val,
	75	unsigned global_limit)
	76	{
	77	unsigned long t;
79a9d994 CH	78	unsigned limit = (1 << 16) - 1;
	79	int err;
	80
e2690695	81	if (*ppos)
79a9d994 CH	82	return -EINVAL;
79a9d994 CH	83
e2690695	84	err = kstrtoul_from_user(buf, count, 0, &t);
79a9d994 CH	85	if (err)
	86	return err;
	87
	88	if (!capable(CAP_SYS_ADMIN))
	89	limit = min(limit, global_limit);
	90
	91	if (t > limit)
	92	return -EINVAL;
	93
	94	*val = t;
	95
	96	return count;
	97	}
	98
	99	static ssize_t fuse_conn_max_background_read(struct file *file,
	100	char __user *buf, size_t len,
	101	loff_t *ppos)
	102	{
	103	struct fuse_conn *fc;
	104	unsigned val;
	105
	106	fc = fuse_ctl_file_conn_get(file);
	107	if (!fc)
	108	return 0;
	109
2a23f2b8	110	val = READ_ONCE(fc->max_background);
79a9d994 CH	111	fuse_conn_put(fc);
	112
	113	return fuse_conn_limit_read(file, buf, len, ppos, val);
	114	}
	115
	116	static ssize_t fuse_conn_max_background_write(struct file *file,
	117	const char __user *buf,
	118	size_t count, loff_t *ppos)
	119	{
381bf7ca	120	unsigned uninitialized_var(val);
79a9d994 CH	121	ssize_t ret;
	122
	123	ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
	124	max_user_bgreq);
	125	if (ret > 0) {
	126	struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
	127	if (fc) {
ae2dffa3	128	spin_lock(&fc->bg_lock);
79a9d994	129	fc->max_background = val;
2b30a533 KT	130	fc->blocked = fc->num_background >= fc->max_background;
	131	if (!fc->blocked)
	132	wake_up(&fc->blocked_waitq);
ae2dffa3	133	spin_unlock(&fc->bg_lock);
79a9d994 CH	134	fuse_conn_put(fc);
	135	}
	136	}
	137
	138	return ret;
	139	}
	140
	141	static ssize_t fuse_conn_congestion_threshold_read(struct file *file,
	142	char __user *buf, size_t len,
	143	loff_t *ppos)
	144	{
	145	struct fuse_conn *fc;
	146	unsigned val;
	147
	148	fc = fuse_ctl_file_conn_get(file);
	149	if (!fc)
	150	return 0;
	151
2a23f2b8	152	val = READ_ONCE(fc->congestion_threshold);
79a9d994 CH	153	fuse_conn_put(fc);
	154
	155	return fuse_conn_limit_read(file, buf, len, ppos, val);
	156	}
	157
	158	static ssize_t fuse_conn_congestion_threshold_write(struct file *file,
	159	const char __user *buf,
	160	size_t count, loff_t *ppos)
	161	{
381bf7ca	162	unsigned uninitialized_var(val);
2b30a533	163	struct fuse_conn *fc;
79a9d994 CH	164	ssize_t ret;
	165
	166	ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
	167	max_user_congthresh);
2b30a533 KT	168	if (ret <= 0)
	169	goto out;
	170	fc = fuse_ctl_file_conn_get(file);
	171	if (!fc)
	172	goto out;
	173
ae2dffa3	174	spin_lock(&fc->bg_lock);
2b30a533 KT	175	fc->congestion_threshold = val;
	176	if (fc->sb) {
	177	if (fc->num_background < fc->congestion_threshold) {
	178	clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
	179	clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
	180	} else {
	181	set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
	182	set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
79a9d994 CH	183	}
79a9d994 CH	184	}
ae2dffa3	185	spin_unlock(&fc->bg_lock);
2b30a533 KT	186	fuse_conn_put(fc);
2b30a533 KT	187	out:
79a9d994 CH	188	return ret;
	189	}
	190
bafa9654 MS	191	static const struct file_operations fuse_ctl_abort_ops = {
	192	.open = nonseekable_open,
	193	.write = fuse_conn_abort_write,
6038f373	194	.llseek = no_llseek,
bafa9654 MS	195	};
	196
	197	static const struct file_operations fuse_ctl_waiting_ops = {
	198	.open = nonseekable_open,
	199	.read = fuse_conn_waiting_read,
6038f373	200	.llseek = no_llseek,
bafa9654 MS	201	};
bafa9654 MS	202
79a9d994 CH	203	static const struct file_operations fuse_conn_max_background_ops = {
	204	.open = nonseekable_open,
	205	.read = fuse_conn_max_background_read,
	206	.write = fuse_conn_max_background_write,
6038f373	207	.llseek = no_llseek,
79a9d994 CH	208	};
	209
	210	static const struct file_operations fuse_conn_congestion_threshold_ops = {
	211	.open = nonseekable_open,
	212	.read = fuse_conn_congestion_threshold_read,
	213	.write = fuse_conn_congestion_threshold_write,
6038f373	214	.llseek = no_llseek,
79a9d994 CH	215	};
79a9d994 CH	216
bafa9654 MS	217	static struct dentry fuse_ctl_add_dentry(struct dentry parent,
	218	struct fuse_conn *fc,
	219	const char *name,
	220	int mode, int nlink,
754661f1	221	const struct inode_operations *iop,
bafa9654 MS	222	const struct file_operations *fop)
	223	{
	224	struct dentry *dentry;
	225	struct inode *inode;
	226
	227	BUG_ON(fc->ctl_ndents >= FUSE_CTL_NUM_DENTRIES);
	228	dentry = d_alloc_name(parent, name);
	229	if (!dentry)
	230	return NULL;
	231
bafa9654	232	inode = new_inode(fuse_control_sb);
6becdb60 MS	233	if (!inode) {
6becdb60 MS	234	dput(dentry);
bafa9654	235	return NULL;
6becdb60	236	}
bafa9654	237
85fe4025	238	inode->i_ino = get_next_ino();
bafa9654 MS	239	inode->i_mode = mode;
	240	inode->i_uid = fc->user_id;
	241	inode->i_gid = fc->group_id;
078cd827	242	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
bafa9654 MS	243	/* setting ->i_op to NULL is not allowed */
	244	if (iop)
	245	inode->i_op = iop;
	246	inode->i_fop = fop;
bfe86848	247	set_nlink(inode, nlink);
8e18e294	248	inode->i_private = fc;
bafa9654	249	d_add(dentry, inode);
6becdb60 MS	250
	251	fc->ctl_dentry[fc->ctl_ndents++] = dentry;
	252
bafa9654 MS	253	return dentry;
	254	}
	255
	256	/*
	257	* Add a connection to the control filesystem (if it exists). Caller
873302c7	258	* must hold fuse_mutex
bafa9654 MS	259	*/
	260	int fuse_ctl_add_conn(struct fuse_conn *fc)
	261	{
	262	struct dentry *parent;
	263	char name[32];
	264
	265	if (!fuse_control_sb)
	266	return 0;
	267
	268	parent = fuse_control_sb->s_root;
2b0143b5	269	inc_nlink(d_inode(parent));
b6f2fcbc	270	sprintf(name, "%u", fc->dev);
bafa9654 MS	271	parent = fuse_ctl_add_dentry(parent, fc, name, S_IFDIR \| 0500, 2,
	272	&simple_dir_inode_operations,
	273	&simple_dir_operations);
	274	if (!parent)
	275	goto err;
	276
	277	if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG \| 0400, 1,
79a9d994	278	NULL, &fuse_ctl_waiting_ops) \|\|
bafa9654	279	!fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG \| 0200, 1,
79a9d994 CH	280	NULL, &fuse_ctl_abort_ops) \|\|
	281	!fuse_ctl_add_dentry(parent, fc, "max_background", S_IFREG \| 0600,
	282	1, NULL, &fuse_conn_max_background_ops) \|\|
	283	!fuse_ctl_add_dentry(parent, fc, "congestion_threshold",
	284	S_IFREG \| 0600, 1, NULL,
	285	&fuse_conn_congestion_threshold_ops))
bafa9654 MS	286	goto err;
	287
	288	return 0;
	289
	290	err:
	291	fuse_ctl_remove_conn(fc);
	292	return -ENOMEM;
	293	}
	294
	295	/*
	296	* Remove a connection from the control filesystem (if it exists).
873302c7	297	* Caller must hold fuse_mutex
bafa9654 MS	298	*/
	299	void fuse_ctl_remove_conn(struct fuse_conn *fc)
	300	{
	301	int i;
	302
	303	if (!fuse_control_sb)
	304	return;
	305
	306	for (i = fc->ctl_ndents - 1; i >= 0; i--) {
	307	struct dentry *dentry = fc->ctl_dentry[i];
2b0143b5	308	d_inode(dentry)->i_private = NULL;
6becdb60 MS	309	if (!i) {
	310	/* Get rid of submounts: */
	311	d_invalidate(dentry);
	312	}
bafa9654 MS	313	dput(dentry);
bafa9654 MS	314	}
2b0143b5	315	drop_nlink(d_inode(fuse_control_sb->s_root));
bafa9654 MS	316	}
	317
	318	static int fuse_ctl_fill_super(struct super_block sb, void data, int silent)
	319	{
cda37124	320	static const struct tree_descr empty_descr = {""};
bafa9654 MS	321	struct fuse_conn *fc;
	322	int err;
	323
	324	err = simple_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr);
	325	if (err)
	326	return err;
	327
	328	mutex_lock(&fuse_mutex);
	329	BUG_ON(fuse_control_sb);
	330	fuse_control_sb = sb;
	331	list_for_each_entry(fc, &fuse_conn_list, entry) {
	332	err = fuse_ctl_add_conn(fc);
	333	if (err) {
	334	fuse_control_sb = NULL;
	335	mutex_unlock(&fuse_mutex);
	336	return err;
	337	}
	338	}
	339	mutex_unlock(&fuse_mutex);
	340
	341	return 0;
	342	}
	343
fc14f2fe AV	344	static struct dentry fuse_ctl_mount(struct file_system_type fs_type,
fc14f2fe AV	345	int flags, const char dev_name, void raw_data)
bafa9654	346	{
fc14f2fe	347	return mount_single(fs_type, flags, raw_data, fuse_ctl_fill_super);
bafa9654 MS	348	}
	349
	350	static void fuse_ctl_kill_sb(struct super_block *sb)
	351	{
ff795447 MS	352	struct fuse_conn *fc;
ff795447 MS	353
bafa9654 MS	354	mutex_lock(&fuse_mutex);
bafa9654 MS	355	fuse_control_sb = NULL;
ff795447 MS	356	list_for_each_entry(fc, &fuse_conn_list, entry)
ff795447 MS	357	fc->ctl_ndents = 0;
bafa9654 MS	358	mutex_unlock(&fuse_mutex);
	359
	360	kill_litter_super(sb);
	361	}
	362
	363	static struct file_system_type fuse_ctl_fs_type = {
	364	.owner = THIS_MODULE,
	365	.name = "fusectl",
fc14f2fe	366	.mount = fuse_ctl_mount,
bafa9654 MS	367	.kill_sb = fuse_ctl_kill_sb,
bafa9654 MS	368	};
7f78e035	369	MODULE_ALIAS_FS("fusectl");
bafa9654 MS	370
	371	int __init fuse_ctl_init(void)
	372	{
	373	return register_filesystem(&fuse_ctl_fs_type);
	374	}
	375
7736e8cc	376	void __exit fuse_ctl_cleanup(void)
bafa9654 MS	377	{
	378	unregister_filesystem(&fuse_ctl_fs_type);
	379	}