xref: /linux/fs/fuse/inode.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>
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/pagemap.h>
12 #include <linux/slab.h>
13 #include <linux/file.h>
14 #include <linux/mount.h>
15 #include <linux/seq_file.h>
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/parser.h>
19 #include <linux/statfs.h>
20 
21 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
22 MODULE_DESCRIPTION("Filesystem in Userspace");
23 MODULE_LICENSE("GPL");
24 
25 static kmem_cache_t *fuse_inode_cachep;
26 static struct subsystem connections_subsys;
27 
28 struct fuse_conn_attr {
29 	struct attribute attr;
30 	ssize_t (*show)(struct fuse_conn *, char *);
31 	ssize_t (*store)(struct fuse_conn *, const char *, size_t);
32 };
33 
34 #define FUSE_SUPER_MAGIC 0x65735546
35 
36 struct fuse_mount_data {
37 	int fd;
38 	unsigned rootmode;
39 	unsigned user_id;
40 	unsigned group_id;
41 	unsigned fd_present : 1;
42 	unsigned rootmode_present : 1;
43 	unsigned user_id_present : 1;
44 	unsigned group_id_present : 1;
45 	unsigned flags;
46 	unsigned max_read;
47 };
48 
49 static struct inode *fuse_alloc_inode(struct super_block *sb)
50 {
51 	struct inode *inode;
52 	struct fuse_inode *fi;
53 
54 	inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
55 	if (!inode)
56 		return NULL;
57 
58 	fi = get_fuse_inode(inode);
59 	fi->i_time = jiffies - 1;
60 	fi->nodeid = 0;
61 	fi->nlookup = 0;
62 	fi->forget_req = fuse_request_alloc();
63 	if (!fi->forget_req) {
64 		kmem_cache_free(fuse_inode_cachep, inode);
65 		return NULL;
66 	}
67 
68 	return inode;
69 }
70 
71 static void fuse_destroy_inode(struct inode *inode)
72 {
73 	struct fuse_inode *fi = get_fuse_inode(inode);
74 	if (fi->forget_req)
75 		fuse_request_free(fi->forget_req);
76 	kmem_cache_free(fuse_inode_cachep, inode);
77 }
78 
79 static void fuse_read_inode(struct inode *inode)
80 {
81 	/* No op */
82 }
83 
84 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
85 		      unsigned long nodeid, u64 nlookup)
86 {
87 	struct fuse_forget_in *inarg = &req->misc.forget_in;
88 	inarg->nlookup = nlookup;
89 	req->in.h.opcode = FUSE_FORGET;
90 	req->in.h.nodeid = nodeid;
91 	req->in.numargs = 1;
92 	req->in.args[0].size = sizeof(struct fuse_forget_in);
93 	req->in.args[0].value = inarg;
94 	request_send_noreply(fc, req);
95 }
96 
97 static void fuse_clear_inode(struct inode *inode)
98 {
99 	if (inode->i_sb->s_flags & MS_ACTIVE) {
100 		struct fuse_conn *fc = get_fuse_conn(inode);
101 		struct fuse_inode *fi = get_fuse_inode(inode);
102 		fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
103 		fi->forget_req = NULL;
104 	}
105 }
106 
107 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
108 {
109 	if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
110 		invalidate_inode_pages(inode->i_mapping);
111 
112 	inode->i_ino     = attr->ino;
113 	inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
114 	inode->i_nlink   = attr->nlink;
115 	inode->i_uid     = attr->uid;
116 	inode->i_gid     = attr->gid;
117 	i_size_write(inode, attr->size);
118 	inode->i_blksize = PAGE_CACHE_SIZE;
119 	inode->i_blocks  = attr->blocks;
120 	inode->i_atime.tv_sec   = attr->atime;
121 	inode->i_atime.tv_nsec  = attr->atimensec;
122 	inode->i_mtime.tv_sec   = attr->mtime;
123 	inode->i_mtime.tv_nsec  = attr->mtimensec;
124 	inode->i_ctime.tv_sec   = attr->ctime;
125 	inode->i_ctime.tv_nsec  = attr->ctimensec;
126 }
127 
128 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
129 {
130 	inode->i_mode = attr->mode & S_IFMT;
131 	i_size_write(inode, attr->size);
132 	if (S_ISREG(inode->i_mode)) {
133 		fuse_init_common(inode);
134 		fuse_init_file_inode(inode);
135 	} else if (S_ISDIR(inode->i_mode))
136 		fuse_init_dir(inode);
137 	else if (S_ISLNK(inode->i_mode))
138 		fuse_init_symlink(inode);
139 	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
140 		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
141 		fuse_init_common(inode);
142 		init_special_inode(inode, inode->i_mode,
143 				   new_decode_dev(attr->rdev));
144 	} else
145 		BUG();
146 }
147 
148 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
149 {
150 	unsigned long nodeid = *(unsigned long *) _nodeidp;
151 	if (get_node_id(inode) == nodeid)
152 		return 1;
153 	else
154 		return 0;
155 }
156 
157 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
158 {
159 	unsigned long nodeid = *(unsigned long *) _nodeidp;
160 	get_fuse_inode(inode)->nodeid = nodeid;
161 	return 0;
162 }
163 
164 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
165 			int generation, struct fuse_attr *attr)
166 {
167 	struct inode *inode;
168 	struct fuse_inode *fi;
169 	struct fuse_conn *fc = get_fuse_conn_super(sb);
170 	int retried = 0;
171 
172  retry:
173 	inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
174 	if (!inode)
175 		return NULL;
176 
177 	if ((inode->i_state & I_NEW)) {
178 		inode->i_flags |= S_NOATIME|S_NOCMTIME;
179 		inode->i_generation = generation;
180 		inode->i_data.backing_dev_info = &fc->bdi;
181 		fuse_init_inode(inode, attr);
182 		unlock_new_inode(inode);
183 	} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
184 		BUG_ON(retried);
185 		/* Inode has changed type, any I/O on the old should fail */
186 		make_bad_inode(inode);
187 		iput(inode);
188 		retried = 1;
189 		goto retry;
190 	}
191 
192 	fi = get_fuse_inode(inode);
193 	fi->nlookup ++;
194 	fuse_change_attributes(inode, attr);
195 	return inode;
196 }
197 
198 static void fuse_umount_begin(struct super_block *sb)
199 {
200 	fuse_abort_conn(get_fuse_conn_super(sb));
201 }
202 
203 static void fuse_put_super(struct super_block *sb)
204 {
205 	struct fuse_conn *fc = get_fuse_conn_super(sb);
206 
207 	down_write(&fc->sbput_sem);
208 	while (!list_empty(&fc->background))
209 		fuse_release_background(fc,
210 					list_entry(fc->background.next,
211 						   struct fuse_req, bg_entry));
212 
213 	spin_lock(&fc->lock);
214 	fc->mounted = 0;
215 	fc->connected = 0;
216 	spin_unlock(&fc->lock);
217 	up_write(&fc->sbput_sem);
218 	/* Flush all readers on this fs */
219 	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
220 	wake_up_all(&fc->waitq);
221 	kobject_del(&fc->kobj);
222 	kobject_put(&fc->kobj);
223 }
224 
225 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
226 {
227 	stbuf->f_type    = FUSE_SUPER_MAGIC;
228 	stbuf->f_bsize   = attr->bsize;
229 	stbuf->f_frsize  = attr->frsize;
230 	stbuf->f_blocks  = attr->blocks;
231 	stbuf->f_bfree   = attr->bfree;
232 	stbuf->f_bavail  = attr->bavail;
233 	stbuf->f_files   = attr->files;
234 	stbuf->f_ffree   = attr->ffree;
235 	stbuf->f_namelen = attr->namelen;
236 	/* fsid is left zero */
237 }
238 
239 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
240 {
241 	struct fuse_conn *fc = get_fuse_conn_super(sb);
242 	struct fuse_req *req;
243 	struct fuse_statfs_out outarg;
244 	int err;
245 
246 	req = fuse_get_req(fc);
247 	if (IS_ERR(req))
248 		return PTR_ERR(req);
249 
250 	memset(&outarg, 0, sizeof(outarg));
251 	req->in.numargs = 0;
252 	req->in.h.opcode = FUSE_STATFS;
253 	req->out.numargs = 1;
254 	req->out.args[0].size =
255 		fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
256 	req->out.args[0].value = &outarg;
257 	request_send(fc, req);
258 	err = req->out.h.error;
259 	if (!err)
260 		convert_fuse_statfs(buf, &outarg.st);
261 	fuse_put_request(fc, req);
262 	return err;
263 }
264 
265 enum {
266 	OPT_FD,
267 	OPT_ROOTMODE,
268 	OPT_USER_ID,
269 	OPT_GROUP_ID,
270 	OPT_DEFAULT_PERMISSIONS,
271 	OPT_ALLOW_OTHER,
272 	OPT_MAX_READ,
273 	OPT_ERR
274 };
275 
276 static match_table_t tokens = {
277 	{OPT_FD,			"fd=%u"},
278 	{OPT_ROOTMODE,			"rootmode=%o"},
279 	{OPT_USER_ID,			"user_id=%u"},
280 	{OPT_GROUP_ID,			"group_id=%u"},
281 	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
282 	{OPT_ALLOW_OTHER,		"allow_other"},
283 	{OPT_MAX_READ,			"max_read=%u"},
284 	{OPT_ERR,			NULL}
285 };
286 
287 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
288 {
289 	char *p;
290 	memset(d, 0, sizeof(struct fuse_mount_data));
291 	d->max_read = ~0;
292 
293 	while ((p = strsep(&opt, ",")) != NULL) {
294 		int token;
295 		int value;
296 		substring_t args[MAX_OPT_ARGS];
297 		if (!*p)
298 			continue;
299 
300 		token = match_token(p, tokens, args);
301 		switch (token) {
302 		case OPT_FD:
303 			if (match_int(&args[0], &value))
304 				return 0;
305 			d->fd = value;
306 			d->fd_present = 1;
307 			break;
308 
309 		case OPT_ROOTMODE:
310 			if (match_octal(&args[0], &value))
311 				return 0;
312 			d->rootmode = value;
313 			d->rootmode_present = 1;
314 			break;
315 
316 		case OPT_USER_ID:
317 			if (match_int(&args[0], &value))
318 				return 0;
319 			d->user_id = value;
320 			d->user_id_present = 1;
321 			break;
322 
323 		case OPT_GROUP_ID:
324 			if (match_int(&args[0], &value))
325 				return 0;
326 			d->group_id = value;
327 			d->group_id_present = 1;
328 			break;
329 
330 		case OPT_DEFAULT_PERMISSIONS:
331 			d->flags |= FUSE_DEFAULT_PERMISSIONS;
332 			break;
333 
334 		case OPT_ALLOW_OTHER:
335 			d->flags |= FUSE_ALLOW_OTHER;
336 			break;
337 
338 		case OPT_MAX_READ:
339 			if (match_int(&args[0], &value))
340 				return 0;
341 			d->max_read = value;
342 			break;
343 
344 		default:
345 			return 0;
346 		}
347 	}
348 
349 	if (!d->fd_present || !d->rootmode_present ||
350 	    !d->user_id_present || !d->group_id_present)
351 		return 0;
352 
353 	return 1;
354 }
355 
356 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
357 {
358 	struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
359 
360 	seq_printf(m, ",user_id=%u", fc->user_id);
361 	seq_printf(m, ",group_id=%u", fc->group_id);
362 	if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
363 		seq_puts(m, ",default_permissions");
364 	if (fc->flags & FUSE_ALLOW_OTHER)
365 		seq_puts(m, ",allow_other");
366 	if (fc->max_read != ~0)
367 		seq_printf(m, ",max_read=%u", fc->max_read);
368 	return 0;
369 }
370 
371 static void fuse_conn_release(struct kobject *kobj)
372 {
373 	kfree(get_fuse_conn_kobj(kobj));
374 }
375 
376 static struct fuse_conn *new_conn(void)
377 {
378 	struct fuse_conn *fc;
379 
380 	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
381 	if (fc) {
382 		spin_lock_init(&fc->lock);
383 		init_waitqueue_head(&fc->waitq);
384 		init_waitqueue_head(&fc->blocked_waitq);
385 		INIT_LIST_HEAD(&fc->pending);
386 		INIT_LIST_HEAD(&fc->processing);
387 		INIT_LIST_HEAD(&fc->io);
388 		INIT_LIST_HEAD(&fc->background);
389 		init_rwsem(&fc->sbput_sem);
390 		kobj_set_kset_s(fc, connections_subsys);
391 		kobject_init(&fc->kobj);
392 		atomic_set(&fc->num_waiting, 0);
393 		fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
394 		fc->bdi.unplug_io_fn = default_unplug_io_fn;
395 		fc->reqctr = 0;
396 		fc->blocked = 1;
397 	}
398 	return fc;
399 }
400 
401 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
402 {
403 	struct fuse_attr attr;
404 	memset(&attr, 0, sizeof(attr));
405 
406 	attr.mode = mode;
407 	attr.ino = FUSE_ROOT_ID;
408 	return fuse_iget(sb, 1, 0, &attr);
409 }
410 
411 static struct super_operations fuse_super_operations = {
412 	.alloc_inode    = fuse_alloc_inode,
413 	.destroy_inode  = fuse_destroy_inode,
414 	.read_inode	= fuse_read_inode,
415 	.clear_inode	= fuse_clear_inode,
416 	.put_super	= fuse_put_super,
417 	.umount_begin	= fuse_umount_begin,
418 	.statfs		= fuse_statfs,
419 	.show_options	= fuse_show_options,
420 };
421 
422 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
423 {
424 	struct fuse_init_out *arg = &req->misc.init_out;
425 
426 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
427 		fc->conn_error = 1;
428 	else {
429 		unsigned long ra_pages;
430 
431 		if (arg->minor >= 6) {
432 			ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
433 			if (arg->flags & FUSE_ASYNC_READ)
434 				fc->async_read = 1;
435 		} else
436 			ra_pages = fc->max_read / PAGE_CACHE_SIZE;
437 
438 		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
439 		fc->minor = arg->minor;
440 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
441 	}
442 	fuse_put_request(fc, req);
443 	fc->blocked = 0;
444 	wake_up_all(&fc->blocked_waitq);
445 }
446 
447 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
448 {
449 	struct fuse_init_in *arg = &req->misc.init_in;
450 
451 	arg->major = FUSE_KERNEL_VERSION;
452 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
453 	arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
454 	arg->flags |= FUSE_ASYNC_READ;
455 	req->in.h.opcode = FUSE_INIT;
456 	req->in.numargs = 1;
457 	req->in.args[0].size = sizeof(*arg);
458 	req->in.args[0].value = arg;
459 	req->out.numargs = 1;
460 	/* Variable length arguement used for backward compatibility
461 	   with interface version < 7.5.  Rest of init_out is zeroed
462 	   by do_get_request(), so a short reply is not a problem */
463 	req->out.argvar = 1;
464 	req->out.args[0].size = sizeof(struct fuse_init_out);
465 	req->out.args[0].value = &req->misc.init_out;
466 	req->end = process_init_reply;
467 	request_send_background(fc, req);
468 }
469 
470 static unsigned long long conn_id(void)
471 {
472 	/* BKL is held for ->get_sb() */
473 	static unsigned long long ctr = 1;
474 	return ctr++;
475 }
476 
477 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
478 {
479 	struct fuse_conn *fc;
480 	struct inode *root;
481 	struct fuse_mount_data d;
482 	struct file *file;
483 	struct dentry *root_dentry;
484 	struct fuse_req *init_req;
485 	int err;
486 
487 	if (!parse_fuse_opt((char *) data, &d))
488 		return -EINVAL;
489 
490 	sb->s_blocksize = PAGE_CACHE_SIZE;
491 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
492 	sb->s_magic = FUSE_SUPER_MAGIC;
493 	sb->s_op = &fuse_super_operations;
494 	sb->s_maxbytes = MAX_LFS_FILESIZE;
495 
496 	file = fget(d.fd);
497 	if (!file)
498 		return -EINVAL;
499 
500 	if (file->f_op != &fuse_dev_operations)
501 		return -EINVAL;
502 
503 	fc = new_conn();
504 	if (!fc)
505 		return -ENOMEM;
506 
507 	fc->flags = d.flags;
508 	fc->user_id = d.user_id;
509 	fc->group_id = d.group_id;
510 	fc->max_read = d.max_read;
511 
512 	/* Used by get_root_inode() */
513 	sb->s_fs_info = fc;
514 
515 	err = -ENOMEM;
516 	root = get_root_inode(sb, d.rootmode);
517 	if (!root)
518 		goto err;
519 
520 	root_dentry = d_alloc_root(root);
521 	if (!root_dentry) {
522 		iput(root);
523 		goto err;
524 	}
525 
526 	init_req = fuse_request_alloc();
527 	if (!init_req)
528 		goto err_put_root;
529 
530 	err = kobject_set_name(&fc->kobj, "%llu", conn_id());
531 	if (err)
532 		goto err_free_req;
533 
534 	err = kobject_add(&fc->kobj);
535 	if (err)
536 		goto err_free_req;
537 
538 	/* Setting file->private_data can't race with other mount()
539 	   instances, since BKL is held for ->get_sb() */
540 	err = -EINVAL;
541 	if (file->private_data)
542 		goto err_kobject_del;
543 
544 	sb->s_root = root_dentry;
545 	fc->mounted = 1;
546 	fc->connected = 1;
547 	kobject_get(&fc->kobj);
548 	file->private_data = fc;
549 	/*
550 	 * atomic_dec_and_test() in fput() provides the necessary
551 	 * memory barrier for file->private_data to be visible on all
552 	 * CPUs after this
553 	 */
554 	fput(file);
555 
556 	fuse_send_init(fc, init_req);
557 
558 	return 0;
559 
560  err_kobject_del:
561 	kobject_del(&fc->kobj);
562  err_free_req:
563 	fuse_request_free(init_req);
564  err_put_root:
565 	dput(root_dentry);
566  err:
567 	fput(file);
568 	kobject_put(&fc->kobj);
569 	return err;
570 }
571 
572 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
573 				       int flags, const char *dev_name,
574 				       void *raw_data)
575 {
576 	return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
577 }
578 
579 static struct file_system_type fuse_fs_type = {
580 	.owner		= THIS_MODULE,
581 	.name		= "fuse",
582 	.get_sb		= fuse_get_sb,
583 	.kill_sb	= kill_anon_super,
584 };
585 
586 static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page)
587 {
588 	return sprintf(page, "%i\n", atomic_read(&fc->num_waiting));
589 }
590 
591 static ssize_t fuse_conn_abort_store(struct fuse_conn *fc, const char *page,
592 				     size_t count)
593 {
594 	fuse_abort_conn(fc);
595 	return count;
596 }
597 
598 static struct fuse_conn_attr fuse_conn_waiting =
599 	__ATTR(waiting, 0400, fuse_conn_waiting_show, NULL);
600 static struct fuse_conn_attr fuse_conn_abort =
601 	__ATTR(abort, 0600, NULL, fuse_conn_abort_store);
602 
603 static struct attribute *fuse_conn_attrs[] = {
604 	&fuse_conn_waiting.attr,
605 	&fuse_conn_abort.attr,
606 	NULL,
607 };
608 
609 static ssize_t fuse_conn_attr_show(struct kobject *kobj,
610 				   struct attribute *attr,
611 				   char *page)
612 {
613 	struct fuse_conn_attr *fca =
614 		container_of(attr, struct fuse_conn_attr, attr);
615 
616 	if (fca->show)
617 		return fca->show(get_fuse_conn_kobj(kobj), page);
618 	else
619 		return -EACCES;
620 }
621 
622 static ssize_t fuse_conn_attr_store(struct kobject *kobj,
623 				    struct attribute *attr,
624 				    const char *page, size_t count)
625 {
626 	struct fuse_conn_attr *fca =
627 		container_of(attr, struct fuse_conn_attr, attr);
628 
629 	if (fca->store)
630 		return fca->store(get_fuse_conn_kobj(kobj), page, count);
631 	else
632 		return -EACCES;
633 }
634 
635 static struct sysfs_ops fuse_conn_sysfs_ops = {
636 	.show	= &fuse_conn_attr_show,
637 	.store	= &fuse_conn_attr_store,
638 };
639 
640 static struct kobj_type ktype_fuse_conn = {
641 	.release	= fuse_conn_release,
642 	.sysfs_ops	= &fuse_conn_sysfs_ops,
643 	.default_attrs	= fuse_conn_attrs,
644 };
645 
646 static decl_subsys(fuse, NULL, NULL);
647 static decl_subsys(connections, &ktype_fuse_conn, NULL);
648 
649 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
650 				 unsigned long flags)
651 {
652 	struct inode * inode = foo;
653 
654 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
655 	    SLAB_CTOR_CONSTRUCTOR)
656 		inode_init_once(inode);
657 }
658 
659 static int __init fuse_fs_init(void)
660 {
661 	int err;
662 
663 	err = register_filesystem(&fuse_fs_type);
664 	if (err)
665 		printk("fuse: failed to register filesystem\n");
666 	else {
667 		fuse_inode_cachep = kmem_cache_create("fuse_inode",
668 						      sizeof(struct fuse_inode),
669 						      0, SLAB_HWCACHE_ALIGN,
670 						      fuse_inode_init_once, NULL);
671 		if (!fuse_inode_cachep) {
672 			unregister_filesystem(&fuse_fs_type);
673 			err = -ENOMEM;
674 		}
675 	}
676 
677 	return err;
678 }
679 
680 static void fuse_fs_cleanup(void)
681 {
682 	unregister_filesystem(&fuse_fs_type);
683 	kmem_cache_destroy(fuse_inode_cachep);
684 }
685 
686 static int fuse_sysfs_init(void)
687 {
688 	int err;
689 
690 	kset_set_kset_s(&fuse_subsys, fs_subsys);
691 	err = subsystem_register(&fuse_subsys);
692 	if (err)
693 		goto out_err;
694 
695 	kset_set_kset_s(&connections_subsys, fuse_subsys);
696 	err = subsystem_register(&connections_subsys);
697 	if (err)
698 		goto out_fuse_unregister;
699 
700 	return 0;
701 
702  out_fuse_unregister:
703 	subsystem_unregister(&fuse_subsys);
704  out_err:
705 	return err;
706 }
707 
708 static void fuse_sysfs_cleanup(void)
709 {
710 	subsystem_unregister(&connections_subsys);
711 	subsystem_unregister(&fuse_subsys);
712 }
713 
714 static int __init fuse_init(void)
715 {
716 	int res;
717 
718 	printk("fuse init (API version %i.%i)\n",
719 	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
720 
721 	res = fuse_fs_init();
722 	if (res)
723 		goto err;
724 
725 	res = fuse_dev_init();
726 	if (res)
727 		goto err_fs_cleanup;
728 
729 	res = fuse_sysfs_init();
730 	if (res)
731 		goto err_dev_cleanup;
732 
733 	return 0;
734 
735  err_dev_cleanup:
736 	fuse_dev_cleanup();
737  err_fs_cleanup:
738 	fuse_fs_cleanup();
739  err:
740 	return res;
741 }
742 
743 static void __exit fuse_exit(void)
744 {
745 	printk(KERN_DEBUG "fuse exit\n");
746 
747 	fuse_sysfs_cleanup();
748 	fuse_fs_cleanup();
749 	fuse_dev_cleanup();
750 }
751 
752 module_init(fuse_init);
753 module_exit(fuse_exit);
754