xref: /linux/fs/fuse/inode.c (revision d8327c784b51b57dac2c26cfad87dce0d68dfd98)
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2005  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 spinlock_t fuse_lock;
26 static kmem_cache_t *fuse_inode_cachep;
27 static struct subsystem connections_subsys;
28 
29 struct fuse_conn_attr {
30 	struct attribute attr;
31 	ssize_t (*show)(struct fuse_conn *, char *);
32 	ssize_t (*store)(struct fuse_conn *, const char *, size_t);
33 };
34 
35 #define FUSE_SUPER_MAGIC 0x65735546
36 
37 struct fuse_mount_data {
38 	int fd;
39 	unsigned rootmode;
40 	unsigned user_id;
41 	unsigned group_id;
42 	unsigned fd_present : 1;
43 	unsigned rootmode_present : 1;
44 	unsigned user_id_present : 1;
45 	unsigned group_id_present : 1;
46 	unsigned flags;
47 	unsigned max_read;
48 };
49 
50 static struct inode *fuse_alloc_inode(struct super_block *sb)
51 {
52 	struct inode *inode;
53 	struct fuse_inode *fi;
54 
55 	inode = kmem_cache_alloc(fuse_inode_cachep, SLAB_KERNEL);
56 	if (!inode)
57 		return NULL;
58 
59 	fi = get_fuse_inode(inode);
60 	fi->i_time = jiffies - 1;
61 	fi->nodeid = 0;
62 	fi->nlookup = 0;
63 	fi->forget_req = fuse_request_alloc();
64 	if (!fi->forget_req) {
65 		kmem_cache_free(fuse_inode_cachep, inode);
66 		return NULL;
67 	}
68 
69 	return inode;
70 }
71 
72 static void fuse_destroy_inode(struct inode *inode)
73 {
74 	struct fuse_inode *fi = get_fuse_inode(inode);
75 	if (fi->forget_req)
76 		fuse_request_free(fi->forget_req);
77 	kmem_cache_free(fuse_inode_cachep, inode);
78 }
79 
80 static void fuse_read_inode(struct inode *inode)
81 {
82 	/* No op */
83 }
84 
85 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
86 		      unsigned long nodeid, u64 nlookup)
87 {
88 	struct fuse_forget_in *inarg = &req->misc.forget_in;
89 	inarg->nlookup = nlookup;
90 	req->in.h.opcode = FUSE_FORGET;
91 	req->in.h.nodeid = nodeid;
92 	req->in.numargs = 1;
93 	req->in.args[0].size = sizeof(struct fuse_forget_in);
94 	req->in.args[0].value = inarg;
95 	request_send_noreply(fc, req);
96 }
97 
98 static void fuse_clear_inode(struct inode *inode)
99 {
100 	if (inode->i_sb->s_flags & MS_ACTIVE) {
101 		struct fuse_conn *fc = get_fuse_conn(inode);
102 		struct fuse_inode *fi = get_fuse_inode(inode);
103 		fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
104 		fi->forget_req = NULL;
105 	}
106 }
107 
108 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
109 {
110 	if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
111 		invalidate_inode_pages(inode->i_mapping);
112 
113 	inode->i_ino     = attr->ino;
114 	inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
115 	inode->i_nlink   = attr->nlink;
116 	inode->i_uid     = attr->uid;
117 	inode->i_gid     = attr->gid;
118 	i_size_write(inode, attr->size);
119 	inode->i_blksize = PAGE_CACHE_SIZE;
120 	inode->i_blocks  = attr->blocks;
121 	inode->i_atime.tv_sec   = attr->atime;
122 	inode->i_atime.tv_nsec  = attr->atimensec;
123 	inode->i_mtime.tv_sec   = attr->mtime;
124 	inode->i_mtime.tv_nsec  = attr->mtimensec;
125 	inode->i_ctime.tv_sec   = attr->ctime;
126 	inode->i_ctime.tv_nsec  = attr->ctimensec;
127 }
128 
129 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
130 {
131 	inode->i_mode = attr->mode & S_IFMT;
132 	i_size_write(inode, attr->size);
133 	if (S_ISREG(inode->i_mode)) {
134 		fuse_init_common(inode);
135 		fuse_init_file_inode(inode);
136 	} else if (S_ISDIR(inode->i_mode))
137 		fuse_init_dir(inode);
138 	else if (S_ISLNK(inode->i_mode))
139 		fuse_init_symlink(inode);
140 	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
141 		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
142 		fuse_init_common(inode);
143 		init_special_inode(inode, inode->i_mode,
144 				   new_decode_dev(attr->rdev));
145 	} else
146 		BUG();
147 }
148 
149 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
150 {
151 	unsigned long nodeid = *(unsigned long *) _nodeidp;
152 	if (get_node_id(inode) == nodeid)
153 		return 1;
154 	else
155 		return 0;
156 }
157 
158 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
159 {
160 	unsigned long nodeid = *(unsigned long *) _nodeidp;
161 	get_fuse_inode(inode)->nodeid = nodeid;
162 	return 0;
163 }
164 
165 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
166 			int generation, struct fuse_attr *attr)
167 {
168 	struct inode *inode;
169 	struct fuse_inode *fi;
170 	struct fuse_conn *fc = get_fuse_conn_super(sb);
171 	int retried = 0;
172 
173  retry:
174 	inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
175 	if (!inode)
176 		return NULL;
177 
178 	if ((inode->i_state & I_NEW)) {
179 		inode->i_flags |= S_NOATIME|S_NOCMTIME;
180 		inode->i_generation = generation;
181 		inode->i_data.backing_dev_info = &fc->bdi;
182 		fuse_init_inode(inode, attr);
183 		unlock_new_inode(inode);
184 	} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
185 		BUG_ON(retried);
186 		/* Inode has changed type, any I/O on the old should fail */
187 		make_bad_inode(inode);
188 		iput(inode);
189 		retried = 1;
190 		goto retry;
191 	}
192 
193 	fi = get_fuse_inode(inode);
194 	fi->nlookup ++;
195 	fuse_change_attributes(inode, attr);
196 	return inode;
197 }
198 
199 static void fuse_umount_begin(struct super_block *sb)
200 {
201 	fuse_abort_conn(get_fuse_conn_super(sb));
202 }
203 
204 static void fuse_put_super(struct super_block *sb)
205 {
206 	struct fuse_conn *fc = get_fuse_conn_super(sb);
207 
208 	down_write(&fc->sbput_sem);
209 	while (!list_empty(&fc->background))
210 		fuse_release_background(list_entry(fc->background.next,
211 						   struct fuse_req, bg_entry));
212 
213 	spin_lock(&fuse_lock);
214 	fc->mounted = 0;
215 	fc->connected = 0;
216 	spin_unlock(&fuse_lock);
217 	up_write(&fc->sbput_sem);
218 	/* Flush all readers on this fs */
219 	wake_up_all(&fc->waitq);
220 	kobject_del(&fc->kobj);
221 	kobject_put(&fc->kobj);
222 }
223 
224 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
225 {
226 	stbuf->f_type    = FUSE_SUPER_MAGIC;
227 	stbuf->f_bsize   = attr->bsize;
228 	stbuf->f_frsize  = attr->frsize;
229 	stbuf->f_blocks  = attr->blocks;
230 	stbuf->f_bfree   = attr->bfree;
231 	stbuf->f_bavail  = attr->bavail;
232 	stbuf->f_files   = attr->files;
233 	stbuf->f_ffree   = attr->ffree;
234 	stbuf->f_namelen = attr->namelen;
235 	/* fsid is left zero */
236 }
237 
238 static int fuse_statfs(struct super_block *sb, struct kstatfs *buf)
239 {
240 	struct fuse_conn *fc = get_fuse_conn_super(sb);
241 	struct fuse_req *req;
242 	struct fuse_statfs_out outarg;
243 	int err;
244 
245         req = fuse_get_request(fc);
246 	if (!req)
247 		return -EINTR;
248 
249 	memset(&outarg, 0, sizeof(outarg));
250 	req->in.numargs = 0;
251 	req->in.h.opcode = FUSE_STATFS;
252 	req->out.numargs = 1;
253 	req->out.args[0].size =
254 		fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
255 	req->out.args[0].value = &outarg;
256 	request_send(fc, req);
257 	err = req->out.h.error;
258 	if (!err)
259 		convert_fuse_statfs(buf, &outarg.st);
260 	fuse_put_request(fc, req);
261 	return err;
262 }
263 
264 enum {
265 	OPT_FD,
266 	OPT_ROOTMODE,
267 	OPT_USER_ID,
268 	OPT_GROUP_ID,
269 	OPT_DEFAULT_PERMISSIONS,
270 	OPT_ALLOW_OTHER,
271 	OPT_MAX_READ,
272 	OPT_ERR
273 };
274 
275 static match_table_t tokens = {
276 	{OPT_FD,			"fd=%u"},
277 	{OPT_ROOTMODE,			"rootmode=%o"},
278 	{OPT_USER_ID,			"user_id=%u"},
279 	{OPT_GROUP_ID,			"group_id=%u"},
280 	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
281 	{OPT_ALLOW_OTHER,		"allow_other"},
282 	{OPT_MAX_READ,			"max_read=%u"},
283 	{OPT_ERR,			NULL}
284 };
285 
286 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
287 {
288 	char *p;
289 	memset(d, 0, sizeof(struct fuse_mount_data));
290 	d->max_read = ~0;
291 
292 	while ((p = strsep(&opt, ",")) != NULL) {
293 		int token;
294 		int value;
295 		substring_t args[MAX_OPT_ARGS];
296 		if (!*p)
297 			continue;
298 
299 		token = match_token(p, tokens, args);
300 		switch (token) {
301 		case OPT_FD:
302 			if (match_int(&args[0], &value))
303 				return 0;
304 			d->fd = value;
305 			d->fd_present = 1;
306 			break;
307 
308 		case OPT_ROOTMODE:
309 			if (match_octal(&args[0], &value))
310 				return 0;
311 			d->rootmode = value;
312 			d->rootmode_present = 1;
313 			break;
314 
315 		case OPT_USER_ID:
316 			if (match_int(&args[0], &value))
317 				return 0;
318 			d->user_id = value;
319 			d->user_id_present = 1;
320 			break;
321 
322 		case OPT_GROUP_ID:
323 			if (match_int(&args[0], &value))
324 				return 0;
325 			d->group_id = value;
326 			d->group_id_present = 1;
327 			break;
328 
329 		case OPT_DEFAULT_PERMISSIONS:
330 			d->flags |= FUSE_DEFAULT_PERMISSIONS;
331 			break;
332 
333 		case OPT_ALLOW_OTHER:
334 			d->flags |= FUSE_ALLOW_OTHER;
335 			break;
336 
337 		case OPT_MAX_READ:
338 			if (match_int(&args[0], &value))
339 				return 0;
340 			d->max_read = value;
341 			break;
342 
343 		default:
344 			return 0;
345 		}
346 	}
347 
348 	if (!d->fd_present || !d->rootmode_present ||
349 	    !d->user_id_present || !d->group_id_present)
350 		return 0;
351 
352 	return 1;
353 }
354 
355 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
356 {
357 	struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
358 
359 	seq_printf(m, ",user_id=%u", fc->user_id);
360 	seq_printf(m, ",group_id=%u", fc->group_id);
361 	if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
362 		seq_puts(m, ",default_permissions");
363 	if (fc->flags & FUSE_ALLOW_OTHER)
364 		seq_puts(m, ",allow_other");
365 	if (fc->max_read != ~0)
366 		seq_printf(m, ",max_read=%u", fc->max_read);
367 	return 0;
368 }
369 
370 static void fuse_conn_release(struct kobject *kobj)
371 {
372 	struct fuse_conn *fc = get_fuse_conn_kobj(kobj);
373 
374 	while (!list_empty(&fc->unused_list)) {
375 		struct fuse_req *req;
376 		req = list_entry(fc->unused_list.next, struct fuse_req, list);
377 		list_del(&req->list);
378 		fuse_request_free(req);
379 	}
380 	kfree(fc);
381 }
382 
383 static struct fuse_conn *new_conn(void)
384 {
385 	struct fuse_conn *fc;
386 
387 	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
388 	if (fc) {
389 		int i;
390 		init_waitqueue_head(&fc->waitq);
391 		INIT_LIST_HEAD(&fc->pending);
392 		INIT_LIST_HEAD(&fc->processing);
393 		INIT_LIST_HEAD(&fc->io);
394 		INIT_LIST_HEAD(&fc->unused_list);
395 		INIT_LIST_HEAD(&fc->background);
396 		sema_init(&fc->outstanding_sem, 1); /* One for INIT */
397 		init_rwsem(&fc->sbput_sem);
398 		kobj_set_kset_s(fc, connections_subsys);
399 		kobject_init(&fc->kobj);
400 		atomic_set(&fc->num_waiting, 0);
401 		for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
402 			struct fuse_req *req = fuse_request_alloc();
403 			if (!req) {
404 				kobject_put(&fc->kobj);
405 				return NULL;
406 			}
407 			list_add(&req->list, &fc->unused_list);
408 		}
409 		fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
410 		fc->bdi.unplug_io_fn = default_unplug_io_fn;
411 		fc->reqctr = 0;
412 	}
413 	return fc;
414 }
415 
416 static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
417 {
418 	struct fuse_conn *fc;
419 	int err;
420 
421 	err = -EINVAL;
422 	if (file->f_op != &fuse_dev_operations)
423 		goto out_err;
424 
425 	err = -ENOMEM;
426 	fc = new_conn();
427 	if (!fc)
428 		goto out_err;
429 
430 	spin_lock(&fuse_lock);
431 	err = -EINVAL;
432 	if (file->private_data)
433 		goto out_unlock;
434 
435 	kobject_get(&fc->kobj);
436 	file->private_data = fc;
437 	spin_unlock(&fuse_lock);
438 	return fc;
439 
440  out_unlock:
441 	spin_unlock(&fuse_lock);
442 	kobject_put(&fc->kobj);
443  out_err:
444 	return ERR_PTR(err);
445 }
446 
447 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
448 {
449 	struct fuse_attr attr;
450 	memset(&attr, 0, sizeof(attr));
451 
452 	attr.mode = mode;
453 	attr.ino = FUSE_ROOT_ID;
454 	return fuse_iget(sb, 1, 0, &attr);
455 }
456 
457 static struct super_operations fuse_super_operations = {
458 	.alloc_inode    = fuse_alloc_inode,
459 	.destroy_inode  = fuse_destroy_inode,
460 	.read_inode	= fuse_read_inode,
461 	.clear_inode	= fuse_clear_inode,
462 	.put_super	= fuse_put_super,
463 	.umount_begin	= fuse_umount_begin,
464 	.statfs		= fuse_statfs,
465 	.show_options	= fuse_show_options,
466 };
467 
468 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
469 {
470 	int i;
471 	struct fuse_init_out *arg = &req->misc.init_out;
472 
473 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
474 		fc->conn_error = 1;
475 	else {
476 		unsigned long ra_pages;
477 
478 		if (arg->minor >= 6) {
479 			ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
480 			if (arg->flags & FUSE_ASYNC_READ)
481 				fc->async_read = 1;
482 		} else
483 			ra_pages = fc->max_read / PAGE_CACHE_SIZE;
484 
485 		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
486 		fc->minor = arg->minor;
487 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
488 	}
489 
490 	/* After INIT reply is received other requests can go
491 	   out.  So do (FUSE_MAX_OUTSTANDING - 1) number of
492 	   up()s on outstanding_sem.  The last up() is done in
493 	   fuse_putback_request() */
494 	for (i = 1; i < FUSE_MAX_OUTSTANDING; i++)
495 		up(&fc->outstanding_sem);
496 
497 	fuse_put_request(fc, req);
498 }
499 
500 static void fuse_send_init(struct fuse_conn *fc)
501 {
502 	/* This is called from fuse_read_super() so there's guaranteed
503 	   to be exactly one request available */
504 	struct fuse_req *req = fuse_get_request(fc);
505 	struct fuse_init_in *arg = &req->misc.init_in;
506 
507 	arg->major = FUSE_KERNEL_VERSION;
508 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
509 	arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
510 	arg->flags |= FUSE_ASYNC_READ;
511 	req->in.h.opcode = FUSE_INIT;
512 	req->in.numargs = 1;
513 	req->in.args[0].size = sizeof(*arg);
514 	req->in.args[0].value = arg;
515 	req->out.numargs = 1;
516 	/* Variable length arguement used for backward compatibility
517 	   with interface version < 7.5.  Rest of init_out is zeroed
518 	   by do_get_request(), so a short reply is not a problem */
519 	req->out.argvar = 1;
520 	req->out.args[0].size = sizeof(struct fuse_init_out);
521 	req->out.args[0].value = &req->misc.init_out;
522 	req->end = process_init_reply;
523 	request_send_background(fc, req);
524 }
525 
526 static unsigned long long conn_id(void)
527 {
528 	static unsigned long long ctr = 1;
529 	unsigned long long val;
530 	spin_lock(&fuse_lock);
531 	val = ctr++;
532 	spin_unlock(&fuse_lock);
533 	return val;
534 }
535 
536 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
537 {
538 	struct fuse_conn *fc;
539 	struct inode *root;
540 	struct fuse_mount_data d;
541 	struct file *file;
542 	struct dentry *root_dentry;
543 	int err;
544 
545 	if (!parse_fuse_opt((char *) data, &d))
546 		return -EINVAL;
547 
548 	sb->s_blocksize = PAGE_CACHE_SIZE;
549 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
550 	sb->s_magic = FUSE_SUPER_MAGIC;
551 	sb->s_op = &fuse_super_operations;
552 	sb->s_maxbytes = MAX_LFS_FILESIZE;
553 
554 	file = fget(d.fd);
555 	if (!file)
556 		return -EINVAL;
557 
558 	fc = get_conn(file, sb);
559 	fput(file);
560 	if (IS_ERR(fc))
561 		return PTR_ERR(fc);
562 
563 	fc->flags = d.flags;
564 	fc->user_id = d.user_id;
565 	fc->group_id = d.group_id;
566 	fc->max_read = d.max_read;
567 
568 	/* Used by get_root_inode() */
569 	sb->s_fs_info = fc;
570 
571 	err = -ENOMEM;
572 	root = get_root_inode(sb, d.rootmode);
573 	if (!root)
574 		goto err;
575 
576 	root_dentry = d_alloc_root(root);
577 	if (!root_dentry) {
578 		iput(root);
579 		goto err;
580 	}
581 
582 	err = kobject_set_name(&fc->kobj, "%llu", conn_id());
583 	if (err)
584 		goto err_put_root;
585 
586 	err = kobject_add(&fc->kobj);
587 	if (err)
588 		goto err_put_root;
589 
590 	sb->s_root = root_dentry;
591 	spin_lock(&fuse_lock);
592 	fc->mounted = 1;
593 	fc->connected = 1;
594 	spin_unlock(&fuse_lock);
595 
596 	fuse_send_init(fc);
597 
598 	return 0;
599 
600  err_put_root:
601 	dput(root_dentry);
602  err:
603 	kobject_put(&fc->kobj);
604 	return err;
605 }
606 
607 static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
608 				       int flags, const char *dev_name,
609 				       void *raw_data)
610 {
611 	return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
612 }
613 
614 static struct file_system_type fuse_fs_type = {
615 	.owner		= THIS_MODULE,
616 	.name		= "fuse",
617 	.get_sb		= fuse_get_sb,
618 	.kill_sb	= kill_anon_super,
619 };
620 
621 static ssize_t fuse_conn_waiting_show(struct fuse_conn *fc, char *page)
622 {
623 	return sprintf(page, "%i\n", atomic_read(&fc->num_waiting));
624 }
625 
626 static ssize_t fuse_conn_abort_store(struct fuse_conn *fc, const char *page,
627 				     size_t count)
628 {
629 	fuse_abort_conn(fc);
630 	return count;
631 }
632 
633 static struct fuse_conn_attr fuse_conn_waiting =
634 	__ATTR(waiting, 0400, fuse_conn_waiting_show, NULL);
635 static struct fuse_conn_attr fuse_conn_abort =
636 	__ATTR(abort, 0600, NULL, fuse_conn_abort_store);
637 
638 static struct attribute *fuse_conn_attrs[] = {
639 	&fuse_conn_waiting.attr,
640 	&fuse_conn_abort.attr,
641 	NULL,
642 };
643 
644 static ssize_t fuse_conn_attr_show(struct kobject *kobj,
645 				   struct attribute *attr,
646 				   char *page)
647 {
648 	struct fuse_conn_attr *fca =
649 		container_of(attr, struct fuse_conn_attr, attr);
650 
651 	if (fca->show)
652 		return fca->show(get_fuse_conn_kobj(kobj), page);
653 	else
654 		return -EACCES;
655 }
656 
657 static ssize_t fuse_conn_attr_store(struct kobject *kobj,
658 				    struct attribute *attr,
659 				    const char *page, size_t count)
660 {
661 	struct fuse_conn_attr *fca =
662 		container_of(attr, struct fuse_conn_attr, attr);
663 
664 	if (fca->store)
665 		return fca->store(get_fuse_conn_kobj(kobj), page, count);
666 	else
667 		return -EACCES;
668 }
669 
670 static struct sysfs_ops fuse_conn_sysfs_ops = {
671 	.show	= &fuse_conn_attr_show,
672 	.store	= &fuse_conn_attr_store,
673 };
674 
675 static struct kobj_type ktype_fuse_conn = {
676 	.release	= fuse_conn_release,
677 	.sysfs_ops	= &fuse_conn_sysfs_ops,
678 	.default_attrs	= fuse_conn_attrs,
679 };
680 
681 static decl_subsys(fuse, NULL, NULL);
682 static decl_subsys(connections, &ktype_fuse_conn, NULL);
683 
684 static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
685 				 unsigned long flags)
686 {
687 	struct inode * inode = foo;
688 
689 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
690 	    SLAB_CTOR_CONSTRUCTOR)
691 		inode_init_once(inode);
692 }
693 
694 static int __init fuse_fs_init(void)
695 {
696 	int err;
697 
698 	err = register_filesystem(&fuse_fs_type);
699 	if (err)
700 		printk("fuse: failed to register filesystem\n");
701 	else {
702 		fuse_inode_cachep = kmem_cache_create("fuse_inode",
703 						      sizeof(struct fuse_inode),
704 						      0, SLAB_HWCACHE_ALIGN,
705 						      fuse_inode_init_once, NULL);
706 		if (!fuse_inode_cachep) {
707 			unregister_filesystem(&fuse_fs_type);
708 			err = -ENOMEM;
709 		}
710 	}
711 
712 	return err;
713 }
714 
715 static void fuse_fs_cleanup(void)
716 {
717 	unregister_filesystem(&fuse_fs_type);
718 	kmem_cache_destroy(fuse_inode_cachep);
719 }
720 
721 static int fuse_sysfs_init(void)
722 {
723 	int err;
724 
725 	kset_set_kset_s(&fuse_subsys, fs_subsys);
726 	err = subsystem_register(&fuse_subsys);
727 	if (err)
728 		goto out_err;
729 
730 	kset_set_kset_s(&connections_subsys, fuse_subsys);
731 	err = subsystem_register(&connections_subsys);
732 	if (err)
733 		goto out_fuse_unregister;
734 
735 	return 0;
736 
737  out_fuse_unregister:
738 	subsystem_unregister(&fuse_subsys);
739  out_err:
740 	return err;
741 }
742 
743 static void fuse_sysfs_cleanup(void)
744 {
745 	subsystem_unregister(&connections_subsys);
746 	subsystem_unregister(&fuse_subsys);
747 }
748 
749 static int __init fuse_init(void)
750 {
751 	int res;
752 
753 	printk("fuse init (API version %i.%i)\n",
754 	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
755 
756 	spin_lock_init(&fuse_lock);
757 	res = fuse_fs_init();
758 	if (res)
759 		goto err;
760 
761 	res = fuse_dev_init();
762 	if (res)
763 		goto err_fs_cleanup;
764 
765 	res = fuse_sysfs_init();
766 	if (res)
767 		goto err_dev_cleanup;
768 
769 	return 0;
770 
771  err_dev_cleanup:
772 	fuse_dev_cleanup();
773  err_fs_cleanup:
774 	fuse_fs_cleanup();
775  err:
776 	return res;
777 }
778 
779 static void __exit fuse_exit(void)
780 {
781 	printk(KERN_DEBUG "fuse exit\n");
782 
783 	fuse_sysfs_cleanup();
784 	fuse_fs_cleanup();
785 	fuse_dev_cleanup();
786 }
787 
788 module_init(fuse_init);
789 module_exit(fuse_exit);
790