[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>
#include <linux/fs_context.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) {
		if (fc->abort_err)
			fc->aborted = true;
		fuse_abort_conn(fc);
		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 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 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;

	down_read(&fc->killsb);
	spin_lock(&fc->bg_lock);
	fc->congestion_threshold = val;
	spin_unlock(&fc->bg_lock);
	up_read(&fc->killsb);
	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 || fc->no_control)
		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 || fc->no_control)
		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, struct fs_context *fsc)
{
	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 int fuse_ctl_get_tree(struct fs_context *fsc)
{
	return get_tree_single(fsc, fuse_ctl_fill_super);
}

static const struct fs_context_operations fuse_ctl_context_ops = {
	.get_tree	= fuse_ctl_get_tree,
};

static int fuse_ctl_init_fs_context(struct fs_context *fsc)
{
	fsc->ops = &fuse_ctl_context_ops;
	return 0;
}

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",
	.init_fs_context = fuse_ctl_init_fs_context,
	.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>
29cc02d9	13	#include <linux/fs_context.h>
bafa9654 MS	14
	15	#define FUSE_CTL_SUPER_MAGIC 0x65735543
	16
	17	/*
	18	* This is non-NULL when the single instance of the control filesystem
	19	* exists. Protected by fuse_mutex
	20	*/
	21	static struct super_block *fuse_control_sb;
	22
	23	static struct fuse_conn fuse_ctl_file_conn_get(struct file file)
	24	{
	25	struct fuse_conn *fc;
	26	mutex_lock(&fuse_mutex);
496ad9aa	27	fc = file_inode(file)->i_private;
bafa9654 MS	28	if (fc)
	29	fc = fuse_conn_get(fc);
	30	mutex_unlock(&fuse_mutex);
	31	return fc;
	32	}
	33
	34	static ssize_t fuse_conn_abort_write(struct file file, const char __user buf,
	35	size_t count, loff_t *ppos)
	36	{
	37	struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
	38	if (fc) {
eb98e3bd MS	39	if (fc->abort_err)
	40	fc->aborted = true;
	41	fuse_abort_conn(fc);
bafa9654 MS	42	fuse_conn_put(fc);
	43	}
	44	return count;
	45	}
	46
	47	static ssize_t fuse_conn_waiting_read(struct file file, char __user buf,
	48	size_t len, loff_t *ppos)
	49	{
	50	char tmp[32];
	51	size_t size;
	52
	53	if (!*ppos) {
1729a16c	54	long value;
bafa9654 MS	55	struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
	56	if (!fc)
	57	return 0;
	58
1729a16c MS	59	value = atomic_read(&fc->num_waiting);
1729a16c MS	60	file->private_data = (void *)value;
bafa9654 MS	61	fuse_conn_put(fc);
	62	}
	63	size = sprintf(tmp, "%ld\n", (long)file->private_data);
	64	return simple_read_from_buffer(buf, len, ppos, tmp, size);
	65	}
	66
79a9d994 CH	67	static ssize_t fuse_conn_limit_read(struct file file, char __user buf,
	68	size_t len, loff_t *ppos, unsigned val)
	69	{
	70	char tmp[32];
	71	size_t size = sprintf(tmp, "%u\n", val);
	72
	73	return simple_read_from_buffer(buf, len, ppos, tmp, size);
	74	}
	75
	76	static ssize_t fuse_conn_limit_write(struct file file, const char __user buf,
	77	size_t count, loff_t ppos, unsigned val,
	78	unsigned global_limit)
	79	{
	80	unsigned long t;
79a9d994 CH	81	unsigned limit = (1 << 16) - 1;
	82	int err;
	83
e2690695	84	if (*ppos)
79a9d994 CH	85	return -EINVAL;
79a9d994 CH	86
e2690695	87	err = kstrtoul_from_user(buf, count, 0, &t);
79a9d994 CH	88	if (err)
	89	return err;
	90
	91	if (!capable(CAP_SYS_ADMIN))
	92	limit = min(limit, global_limit);
	93
	94	if (t > limit)
	95	return -EINVAL;
	96
	97	*val = t;
	98
	99	return count;
	100	}
	101
	102	static ssize_t fuse_conn_max_background_read(struct file *file,
	103	char __user *buf, size_t len,
	104	loff_t *ppos)
	105	{
	106	struct fuse_conn *fc;
	107	unsigned val;
	108
	109	fc = fuse_ctl_file_conn_get(file);
	110	if (!fc)
	111	return 0;
	112
2a23f2b8	113	val = READ_ONCE(fc->max_background);
79a9d994 CH	114	fuse_conn_put(fc);
	115
	116	return fuse_conn_limit_read(file, buf, len, ppos, val);
	117	}
	118
	119	static ssize_t fuse_conn_max_background_write(struct file *file,
	120	const char __user *buf,
	121	size_t count, loff_t *ppos)
	122	{
3f649ab7	123	unsigned val;
79a9d994 CH	124	ssize_t ret;
	125
	126	ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
	127	max_user_bgreq);
	128	if (ret > 0) {
	129	struct fuse_conn *fc = fuse_ctl_file_conn_get(file);
	130	if (fc) {
ae2dffa3	131	spin_lock(&fc->bg_lock);
79a9d994	132	fc->max_background = val;
2b30a533 KT	133	fc->blocked = fc->num_background >= fc->max_background;
	134	if (!fc->blocked)
	135	wake_up(&fc->blocked_waitq);
ae2dffa3	136	spin_unlock(&fc->bg_lock);
79a9d994 CH	137	fuse_conn_put(fc);
	138	}
	139	}
	140
	141	return ret;
	142	}
	143
	144	static ssize_t fuse_conn_congestion_threshold_read(struct file *file,
	145	char __user *buf, size_t len,
	146	loff_t *ppos)
	147	{
	148	struct fuse_conn *fc;
	149	unsigned val;
	150
	151	fc = fuse_ctl_file_conn_get(file);
	152	if (!fc)
	153	return 0;
	154
2a23f2b8	155	val = READ_ONCE(fc->congestion_threshold);
79a9d994 CH	156	fuse_conn_put(fc);
	157
	158	return fuse_conn_limit_read(file, buf, len, ppos, val);
	159	}
	160
	161	static ssize_t fuse_conn_congestion_threshold_write(struct file *file,
	162	const char __user *buf,
	163	size_t count, loff_t *ppos)
	164	{
3f649ab7	165	unsigned val;
2b30a533	166	struct fuse_conn *fc;
79a9d994 CH	167	ssize_t ret;
	168
	169	ret = fuse_conn_limit_write(file, buf, count, ppos, &val,
	170	max_user_congthresh);
2b30a533 KT	171	if (ret <= 0)
	172	goto out;
	173	fc = fuse_ctl_file_conn_get(file);
	174	if (!fc)
	175	goto out;
	176
fcee216b	177	down_read(&fc->killsb);
ae2dffa3	178	spin_lock(&fc->bg_lock);
2b30a533	179	fc->congestion_threshold = val;
ae2dffa3	180	spin_unlock(&fc->bg_lock);
fcee216b	181	up_read(&fc->killsb);
2b30a533 KT	182	fuse_conn_put(fc);
2b30a533 KT	183	out:
79a9d994 CH	184	return ret;
	185	}
	186
bafa9654 MS	187	static const struct file_operations fuse_ctl_abort_ops = {
	188	.open = nonseekable_open,
	189	.write = fuse_conn_abort_write,
6038f373	190	.llseek = no_llseek,
bafa9654 MS	191	};
	192
	193	static const struct file_operations fuse_ctl_waiting_ops = {
	194	.open = nonseekable_open,
	195	.read = fuse_conn_waiting_read,
6038f373	196	.llseek = no_llseek,
bafa9654 MS	197	};
bafa9654 MS	198
79a9d994 CH	199	static const struct file_operations fuse_conn_max_background_ops = {
	200	.open = nonseekable_open,
	201	.read = fuse_conn_max_background_read,
	202	.write = fuse_conn_max_background_write,
6038f373	203	.llseek = no_llseek,
79a9d994 CH	204	};
	205
	206	static const struct file_operations fuse_conn_congestion_threshold_ops = {
	207	.open = nonseekable_open,
	208	.read = fuse_conn_congestion_threshold_read,
	209	.write = fuse_conn_congestion_threshold_write,
6038f373	210	.llseek = no_llseek,
79a9d994 CH	211	};
79a9d994 CH	212
bafa9654 MS	213	static struct dentry fuse_ctl_add_dentry(struct dentry parent,
	214	struct fuse_conn *fc,
	215	const char *name,
	216	int mode, int nlink,
754661f1	217	const struct inode_operations *iop,
bafa9654 MS	218	const struct file_operations *fop)
	219	{
	220	struct dentry *dentry;
	221	struct inode *inode;
	222
	223	BUG_ON(fc->ctl_ndents >= FUSE_CTL_NUM_DENTRIES);
	224	dentry = d_alloc_name(parent, name);
	225	if (!dentry)
	226	return NULL;
	227
bafa9654	228	inode = new_inode(fuse_control_sb);
6becdb60 MS	229	if (!inode) {
6becdb60 MS	230	dput(dentry);
bafa9654	231	return NULL;
6becdb60	232	}
bafa9654	233
85fe4025	234	inode->i_ino = get_next_ino();
bafa9654 MS	235	inode->i_mode = mode;
	236	inode->i_uid = fc->user_id;
	237	inode->i_gid = fc->group_id;
078cd827	238	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
bafa9654 MS	239	/* setting ->i_op to NULL is not allowed */
	240	if (iop)
	241	inode->i_op = iop;
	242	inode->i_fop = fop;
bfe86848	243	set_nlink(inode, nlink);
8e18e294	244	inode->i_private = fc;
bafa9654	245	d_add(dentry, inode);
6becdb60 MS	246
	247	fc->ctl_dentry[fc->ctl_ndents++] = dentry;
	248
bafa9654 MS	249	return dentry;
	250	}
	251
	252	/*
	253	* Add a connection to the control filesystem (if it exists). Caller
873302c7	254	* must hold fuse_mutex
bafa9654 MS	255	*/
	256	int fuse_ctl_add_conn(struct fuse_conn *fc)
	257	{
	258	struct dentry *parent;
	259	char name[32];
	260
c6479780	261	if (!fuse_control_sb \|\| fc->no_control)
bafa9654 MS	262	return 0;
	263
	264	parent = fuse_control_sb->s_root;
2b0143b5	265	inc_nlink(d_inode(parent));
b6f2fcbc	266	sprintf(name, "%u", fc->dev);
bafa9654 MS	267	parent = fuse_ctl_add_dentry(parent, fc, name, S_IFDIR \| 0500, 2,
	268	&simple_dir_inode_operations,
	269	&simple_dir_operations);
	270	if (!parent)
	271	goto err;
	272
	273	if (!fuse_ctl_add_dentry(parent, fc, "waiting", S_IFREG \| 0400, 1,
79a9d994	274	NULL, &fuse_ctl_waiting_ops) \|\|
bafa9654	275	!fuse_ctl_add_dentry(parent, fc, "abort", S_IFREG \| 0200, 1,
79a9d994 CH	276	NULL, &fuse_ctl_abort_ops) \|\|
	277	!fuse_ctl_add_dentry(parent, fc, "max_background", S_IFREG \| 0600,
	278	1, NULL, &fuse_conn_max_background_ops) \|\|
	279	!fuse_ctl_add_dentry(parent, fc, "congestion_threshold",
	280	S_IFREG \| 0600, 1, NULL,
	281	&fuse_conn_congestion_threshold_ops))
bafa9654 MS	282	goto err;
	283
	284	return 0;
	285
	286	err:
	287	fuse_ctl_remove_conn(fc);
	288	return -ENOMEM;
	289	}
	290
	291	/*
	292	* Remove a connection from the control filesystem (if it exists).
873302c7	293	* Caller must hold fuse_mutex
bafa9654 MS	294	*/
	295	void fuse_ctl_remove_conn(struct fuse_conn *fc)
	296	{
	297	int i;
	298
c6479780	299	if (!fuse_control_sb \|\| fc->no_control)
bafa9654 MS	300	return;
	301
	302	for (i = fc->ctl_ndents - 1; i >= 0; i--) {
	303	struct dentry *dentry = fc->ctl_dentry[i];
2b0143b5	304	d_inode(dentry)->i_private = NULL;
6becdb60 MS	305	if (!i) {
	306	/* Get rid of submounts: */
	307	d_invalidate(dentry);
	308	}
bafa9654 MS	309	dput(dentry);
bafa9654 MS	310	}
2b0143b5	311	drop_nlink(d_inode(fuse_control_sb->s_root));
bafa9654 MS	312	}
bafa9654 MS	313
84c21507	314	static int fuse_ctl_fill_super(struct super_block sb, struct fs_context fsc)
bafa9654	315	{
cda37124	316	static const struct tree_descr empty_descr = {""};
bafa9654 MS	317	struct fuse_conn *fc;
	318	int err;
	319
	320	err = simple_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr);
	321	if (err)
	322	return err;
	323
	324	mutex_lock(&fuse_mutex);
	325	BUG_ON(fuse_control_sb);
	326	fuse_control_sb = sb;
	327	list_for_each_entry(fc, &fuse_conn_list, entry) {
	328	err = fuse_ctl_add_conn(fc);
	329	if (err) {
	330	fuse_control_sb = NULL;
	331	mutex_unlock(&fuse_mutex);
	332	return err;
	333	}
	334	}
	335	mutex_unlock(&fuse_mutex);
	336
	337	return 0;
	338	}
	339
84c21507	340	static int fuse_ctl_get_tree(struct fs_context *fsc)
bafa9654	341	{
84c21507	342	return get_tree_single(fsc, fuse_ctl_fill_super);
29cc02d9 DH	343	}
	344
	345	static const struct fs_context_operations fuse_ctl_context_ops = {
	346	.get_tree = fuse_ctl_get_tree,
	347	};
	348
84c21507	349	static int fuse_ctl_init_fs_context(struct fs_context *fsc)
29cc02d9	350	{
84c21507	351	fsc->ops = &fuse_ctl_context_ops;
29cc02d9	352	return 0;
bafa9654 MS	353	}
	354
	355	static void fuse_ctl_kill_sb(struct super_block *sb)
	356	{
ff795447 MS	357	struct fuse_conn *fc;
ff795447 MS	358
bafa9654 MS	359	mutex_lock(&fuse_mutex);
bafa9654 MS	360	fuse_control_sb = NULL;
ff795447 MS	361	list_for_each_entry(fc, &fuse_conn_list, entry)
ff795447 MS	362	fc->ctl_ndents = 0;
bafa9654 MS	363	mutex_unlock(&fuse_mutex);
	364
	365	kill_litter_super(sb);
	366	}
	367
	368	static struct file_system_type fuse_ctl_fs_type = {
	369	.owner = THIS_MODULE,
	370	.name = "fusectl",
29cc02d9	371	.init_fs_context = fuse_ctl_init_fs_context,
bafa9654 MS	372	.kill_sb = fuse_ctl_kill_sb,
bafa9654 MS	373	};
7f78e035	374	MODULE_ALIAS_FS("fusectl");
bafa9654 MS	375
	376	int __init fuse_ctl_init(void)
	377	{
	378	return register_filesystem(&fuse_ctl_fs_type);
	379	}
	380
7736e8cc	381	void __exit fuse_ctl_cleanup(void)
bafa9654 MS	382	{
	383	unregister_filesystem(&fuse_ctl_fs_type);
	384	}