xref: /linux/fs/fuse/inode.c (revision c537b994505099b7197e7d3125b942ecbcc51eb6)
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/seq_file.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/parser.h>
18 #include <linux/statfs.h>
19 #include <linux/random.h>
20 
21 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
22 MODULE_DESCRIPTION("Filesystem in Userspace");
23 MODULE_LICENSE("GPL");
24 
25 static struct kmem_cache *fuse_inode_cachep;
26 struct list_head fuse_conn_list;
27 DEFINE_MUTEX(fuse_mutex);
28 
29 #define FUSE_SUPER_MAGIC 0x65735546
30 
31 struct fuse_mount_data {
32 	int fd;
33 	unsigned rootmode;
34 	unsigned user_id;
35 	unsigned group_id;
36 	unsigned fd_present : 1;
37 	unsigned rootmode_present : 1;
38 	unsigned user_id_present : 1;
39 	unsigned group_id_present : 1;
40 	unsigned flags;
41 	unsigned max_read;
42 	unsigned blksize;
43 };
44 
45 static struct inode *fuse_alloc_inode(struct super_block *sb)
46 {
47 	struct inode *inode;
48 	struct fuse_inode *fi;
49 
50 	inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
51 	if (!inode)
52 		return NULL;
53 
54 	fi = get_fuse_inode(inode);
55 	fi->i_time = 0;
56 	fi->nodeid = 0;
57 	fi->nlookup = 0;
58 	fi->forget_req = fuse_request_alloc();
59 	if (!fi->forget_req) {
60 		kmem_cache_free(fuse_inode_cachep, inode);
61 		return NULL;
62 	}
63 
64 	return inode;
65 }
66 
67 static void fuse_destroy_inode(struct inode *inode)
68 {
69 	struct fuse_inode *fi = get_fuse_inode(inode);
70 	if (fi->forget_req)
71 		fuse_request_free(fi->forget_req);
72 	kmem_cache_free(fuse_inode_cachep, inode);
73 }
74 
75 static void fuse_read_inode(struct inode *inode)
76 {
77 	/* No op */
78 }
79 
80 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
81 		      unsigned long nodeid, u64 nlookup)
82 {
83 	struct fuse_forget_in *inarg = &req->misc.forget_in;
84 	inarg->nlookup = nlookup;
85 	req->in.h.opcode = FUSE_FORGET;
86 	req->in.h.nodeid = nodeid;
87 	req->in.numargs = 1;
88 	req->in.args[0].size = sizeof(struct fuse_forget_in);
89 	req->in.args[0].value = inarg;
90 	request_send_noreply(fc, req);
91 }
92 
93 static void fuse_clear_inode(struct inode *inode)
94 {
95 	if (inode->i_sb->s_flags & MS_ACTIVE) {
96 		struct fuse_conn *fc = get_fuse_conn(inode);
97 		struct fuse_inode *fi = get_fuse_inode(inode);
98 		fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
99 		fi->forget_req = NULL;
100 	}
101 }
102 
103 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
104 {
105 	if (*flags & MS_MANDLOCK)
106 		return -EINVAL;
107 
108 	return 0;
109 }
110 
111 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
112 {
113 	struct fuse_conn *fc = get_fuse_conn(inode);
114 	if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
115 		invalidate_mapping_pages(inode->i_mapping, 0, -1);
116 
117 	inode->i_ino     = attr->ino;
118 	inode->i_mode    = (inode->i_mode & S_IFMT) + (attr->mode & 07777);
119 	inode->i_nlink   = attr->nlink;
120 	inode->i_uid     = attr->uid;
121 	inode->i_gid     = attr->gid;
122 	spin_lock(&fc->lock);
123 	i_size_write(inode, attr->size);
124 	spin_unlock(&fc->lock);
125 	inode->i_blocks  = attr->blocks;
126 	inode->i_atime.tv_sec   = attr->atime;
127 	inode->i_atime.tv_nsec  = attr->atimensec;
128 	inode->i_mtime.tv_sec   = attr->mtime;
129 	inode->i_mtime.tv_nsec  = attr->mtimensec;
130 	inode->i_ctime.tv_sec   = attr->ctime;
131 	inode->i_ctime.tv_nsec  = attr->ctimensec;
132 }
133 
134 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
135 {
136 	inode->i_mode = attr->mode & S_IFMT;
137 	inode->i_size = attr->size;
138 	if (S_ISREG(inode->i_mode)) {
139 		fuse_init_common(inode);
140 		fuse_init_file_inode(inode);
141 	} else if (S_ISDIR(inode->i_mode))
142 		fuse_init_dir(inode);
143 	else if (S_ISLNK(inode->i_mode))
144 		fuse_init_symlink(inode);
145 	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
146 		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
147 		fuse_init_common(inode);
148 		init_special_inode(inode, inode->i_mode,
149 				   new_decode_dev(attr->rdev));
150 	} else
151 		BUG();
152 }
153 
154 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
155 {
156 	unsigned long nodeid = *(unsigned long *) _nodeidp;
157 	if (get_node_id(inode) == nodeid)
158 		return 1;
159 	else
160 		return 0;
161 }
162 
163 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
164 {
165 	unsigned long nodeid = *(unsigned long *) _nodeidp;
166 	get_fuse_inode(inode)->nodeid = nodeid;
167 	return 0;
168 }
169 
170 struct inode *fuse_iget(struct super_block *sb, unsigned long nodeid,
171 			int generation, struct fuse_attr *attr)
172 {
173 	struct inode *inode;
174 	struct fuse_inode *fi;
175 	struct fuse_conn *fc = get_fuse_conn_super(sb);
176 
177  retry:
178 	inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
179 	if (!inode)
180 		return NULL;
181 
182 	if ((inode->i_state & I_NEW)) {
183 		inode->i_flags |= S_NOATIME|S_NOCMTIME;
184 		inode->i_generation = generation;
185 		inode->i_data.backing_dev_info = &fc->bdi;
186 		fuse_init_inode(inode, attr);
187 		unlock_new_inode(inode);
188 	} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
189 		/* Inode has changed type, any I/O on the old should fail */
190 		make_bad_inode(inode);
191 		iput(inode);
192 		goto retry;
193 	}
194 
195 	fi = get_fuse_inode(inode);
196 	spin_lock(&fc->lock);
197 	fi->nlookup ++;
198 	spin_unlock(&fc->lock);
199 	fuse_change_attributes(inode, attr);
200 	return inode;
201 }
202 
203 static void fuse_umount_begin(struct vfsmount *vfsmnt, int flags)
204 {
205 	if (flags & MNT_FORCE)
206 		fuse_abort_conn(get_fuse_conn_super(vfsmnt->mnt_sb));
207 }
208 
209 static void fuse_send_destroy(struct fuse_conn *fc)
210 {
211 	struct fuse_req *req = fc->destroy_req;
212 	if (req && fc->conn_init) {
213 		fc->destroy_req = NULL;
214 		req->in.h.opcode = FUSE_DESTROY;
215 		req->force = 1;
216 		request_send(fc, req);
217 		fuse_put_request(fc, req);
218 	}
219 }
220 
221 static void fuse_put_super(struct super_block *sb)
222 {
223 	struct fuse_conn *fc = get_fuse_conn_super(sb);
224 
225 	fuse_send_destroy(fc);
226 	spin_lock(&fc->lock);
227 	fc->connected = 0;
228 	fc->blocked = 0;
229 	spin_unlock(&fc->lock);
230 	/* Flush all readers on this fs */
231 	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
232 	wake_up_all(&fc->waitq);
233 	wake_up_all(&fc->blocked_waitq);
234 	mutex_lock(&fuse_mutex);
235 	list_del(&fc->entry);
236 	fuse_ctl_remove_conn(fc);
237 	mutex_unlock(&fuse_mutex);
238 	fuse_conn_put(fc);
239 }
240 
241 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
242 {
243 	stbuf->f_type    = FUSE_SUPER_MAGIC;
244 	stbuf->f_bsize   = attr->bsize;
245 	stbuf->f_frsize  = attr->frsize;
246 	stbuf->f_blocks  = attr->blocks;
247 	stbuf->f_bfree   = attr->bfree;
248 	stbuf->f_bavail  = attr->bavail;
249 	stbuf->f_files   = attr->files;
250 	stbuf->f_ffree   = attr->ffree;
251 	stbuf->f_namelen = attr->namelen;
252 	/* fsid is left zero */
253 }
254 
255 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
256 {
257 	struct super_block *sb = dentry->d_sb;
258 	struct fuse_conn *fc = get_fuse_conn_super(sb);
259 	struct fuse_req *req;
260 	struct fuse_statfs_out outarg;
261 	int err;
262 
263 	req = fuse_get_req(fc);
264 	if (IS_ERR(req))
265 		return PTR_ERR(req);
266 
267 	memset(&outarg, 0, sizeof(outarg));
268 	req->in.numargs = 0;
269 	req->in.h.opcode = FUSE_STATFS;
270 	req->in.h.nodeid = get_node_id(dentry->d_inode);
271 	req->out.numargs = 1;
272 	req->out.args[0].size =
273 		fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
274 	req->out.args[0].value = &outarg;
275 	request_send(fc, req);
276 	err = req->out.h.error;
277 	if (!err)
278 		convert_fuse_statfs(buf, &outarg.st);
279 	fuse_put_request(fc, req);
280 	return err;
281 }
282 
283 enum {
284 	OPT_FD,
285 	OPT_ROOTMODE,
286 	OPT_USER_ID,
287 	OPT_GROUP_ID,
288 	OPT_DEFAULT_PERMISSIONS,
289 	OPT_ALLOW_OTHER,
290 	OPT_MAX_READ,
291 	OPT_BLKSIZE,
292 	OPT_ERR
293 };
294 
295 static match_table_t tokens = {
296 	{OPT_FD,			"fd=%u"},
297 	{OPT_ROOTMODE,			"rootmode=%o"},
298 	{OPT_USER_ID,			"user_id=%u"},
299 	{OPT_GROUP_ID,			"group_id=%u"},
300 	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
301 	{OPT_ALLOW_OTHER,		"allow_other"},
302 	{OPT_MAX_READ,			"max_read=%u"},
303 	{OPT_BLKSIZE,			"blksize=%u"},
304 	{OPT_ERR,			NULL}
305 };
306 
307 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
308 {
309 	char *p;
310 	memset(d, 0, sizeof(struct fuse_mount_data));
311 	d->max_read = ~0;
312 	d->blksize = 512;
313 
314 	while ((p = strsep(&opt, ",")) != NULL) {
315 		int token;
316 		int value;
317 		substring_t args[MAX_OPT_ARGS];
318 		if (!*p)
319 			continue;
320 
321 		token = match_token(p, tokens, args);
322 		switch (token) {
323 		case OPT_FD:
324 			if (match_int(&args[0], &value))
325 				return 0;
326 			d->fd = value;
327 			d->fd_present = 1;
328 			break;
329 
330 		case OPT_ROOTMODE:
331 			if (match_octal(&args[0], &value))
332 				return 0;
333 			d->rootmode = value;
334 			d->rootmode_present = 1;
335 			break;
336 
337 		case OPT_USER_ID:
338 			if (match_int(&args[0], &value))
339 				return 0;
340 			d->user_id = value;
341 			d->user_id_present = 1;
342 			break;
343 
344 		case OPT_GROUP_ID:
345 			if (match_int(&args[0], &value))
346 				return 0;
347 			d->group_id = value;
348 			d->group_id_present = 1;
349 			break;
350 
351 		case OPT_DEFAULT_PERMISSIONS:
352 			d->flags |= FUSE_DEFAULT_PERMISSIONS;
353 			break;
354 
355 		case OPT_ALLOW_OTHER:
356 			d->flags |= FUSE_ALLOW_OTHER;
357 			break;
358 
359 		case OPT_MAX_READ:
360 			if (match_int(&args[0], &value))
361 				return 0;
362 			d->max_read = value;
363 			break;
364 
365 		case OPT_BLKSIZE:
366 			if (!is_bdev || match_int(&args[0], &value))
367 				return 0;
368 			d->blksize = value;
369 			break;
370 
371 		default:
372 			return 0;
373 		}
374 	}
375 
376 	if (!d->fd_present || !d->rootmode_present ||
377 	    !d->user_id_present || !d->group_id_present)
378 		return 0;
379 
380 	return 1;
381 }
382 
383 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
384 {
385 	struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
386 
387 	seq_printf(m, ",user_id=%u", fc->user_id);
388 	seq_printf(m, ",group_id=%u", fc->group_id);
389 	if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
390 		seq_puts(m, ",default_permissions");
391 	if (fc->flags & FUSE_ALLOW_OTHER)
392 		seq_puts(m, ",allow_other");
393 	if (fc->max_read != ~0)
394 		seq_printf(m, ",max_read=%u", fc->max_read);
395 	return 0;
396 }
397 
398 static struct fuse_conn *new_conn(void)
399 {
400 	struct fuse_conn *fc;
401 
402 	fc = kzalloc(sizeof(*fc), GFP_KERNEL);
403 	if (fc) {
404 		spin_lock_init(&fc->lock);
405 		mutex_init(&fc->inst_mutex);
406 		atomic_set(&fc->count, 1);
407 		init_waitqueue_head(&fc->waitq);
408 		init_waitqueue_head(&fc->blocked_waitq);
409 		INIT_LIST_HEAD(&fc->pending);
410 		INIT_LIST_HEAD(&fc->processing);
411 		INIT_LIST_HEAD(&fc->io);
412 		INIT_LIST_HEAD(&fc->interrupts);
413 		atomic_set(&fc->num_waiting, 0);
414 		fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
415 		fc->bdi.unplug_io_fn = default_unplug_io_fn;
416 		fc->reqctr = 0;
417 		fc->blocked = 1;
418 		get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
419 	}
420 	return fc;
421 }
422 
423 void fuse_conn_put(struct fuse_conn *fc)
424 {
425 	if (atomic_dec_and_test(&fc->count)) {
426 		if (fc->destroy_req)
427 			fuse_request_free(fc->destroy_req);
428 		mutex_destroy(&fc->inst_mutex);
429 		kfree(fc);
430 	}
431 }
432 
433 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
434 {
435 	atomic_inc(&fc->count);
436 	return fc;
437 }
438 
439 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
440 {
441 	struct fuse_attr attr;
442 	memset(&attr, 0, sizeof(attr));
443 
444 	attr.mode = mode;
445 	attr.ino = FUSE_ROOT_ID;
446 	return fuse_iget(sb, 1, 0, &attr);
447 }
448 
449 static const struct super_operations fuse_super_operations = {
450 	.alloc_inode    = fuse_alloc_inode,
451 	.destroy_inode  = fuse_destroy_inode,
452 	.read_inode	= fuse_read_inode,
453 	.clear_inode	= fuse_clear_inode,
454 	.remount_fs	= fuse_remount_fs,
455 	.put_super	= fuse_put_super,
456 	.umount_begin	= fuse_umount_begin,
457 	.statfs		= fuse_statfs,
458 	.show_options	= fuse_show_options,
459 };
460 
461 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
462 {
463 	struct fuse_init_out *arg = &req->misc.init_out;
464 
465 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
466 		fc->conn_error = 1;
467 	else {
468 		unsigned long ra_pages;
469 
470 		if (arg->minor >= 6) {
471 			ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
472 			if (arg->flags & FUSE_ASYNC_READ)
473 				fc->async_read = 1;
474 			if (!(arg->flags & FUSE_POSIX_LOCKS))
475 				fc->no_lock = 1;
476 		} else {
477 			ra_pages = fc->max_read / PAGE_CACHE_SIZE;
478 			fc->no_lock = 1;
479 		}
480 
481 		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
482 		fc->minor = arg->minor;
483 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
484 		fc->conn_init = 1;
485 	}
486 	fuse_put_request(fc, req);
487 	fc->blocked = 0;
488 	wake_up_all(&fc->blocked_waitq);
489 }
490 
491 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
492 {
493 	struct fuse_init_in *arg = &req->misc.init_in;
494 
495 	arg->major = FUSE_KERNEL_VERSION;
496 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
497 	arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
498 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS;
499 	req->in.h.opcode = FUSE_INIT;
500 	req->in.numargs = 1;
501 	req->in.args[0].size = sizeof(*arg);
502 	req->in.args[0].value = arg;
503 	req->out.numargs = 1;
504 	/* Variable length arguement used for backward compatibility
505 	   with interface version < 7.5.  Rest of init_out is zeroed
506 	   by do_get_request(), so a short reply is not a problem */
507 	req->out.argvar = 1;
508 	req->out.args[0].size = sizeof(struct fuse_init_out);
509 	req->out.args[0].value = &req->misc.init_out;
510 	req->end = process_init_reply;
511 	request_send_background(fc, req);
512 }
513 
514 static u64 conn_id(void)
515 {
516 	static u64 ctr = 1;
517 	return ctr++;
518 }
519 
520 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
521 {
522 	struct fuse_conn *fc;
523 	struct inode *root;
524 	struct fuse_mount_data d;
525 	struct file *file;
526 	struct dentry *root_dentry;
527 	struct fuse_req *init_req;
528 	int err;
529 	int is_bdev = sb->s_bdev != NULL;
530 
531 	if (sb->s_flags & MS_MANDLOCK)
532 		return -EINVAL;
533 
534 	if (!parse_fuse_opt((char *) data, &d, is_bdev))
535 		return -EINVAL;
536 
537 	if (is_bdev) {
538 #ifdef CONFIG_BLOCK
539 		if (!sb_set_blocksize(sb, d.blksize))
540 			return -EINVAL;
541 #endif
542 	} else {
543 		sb->s_blocksize = PAGE_CACHE_SIZE;
544 		sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
545 	}
546 	sb->s_magic = FUSE_SUPER_MAGIC;
547 	sb->s_op = &fuse_super_operations;
548 	sb->s_maxbytes = MAX_LFS_FILESIZE;
549 
550 	file = fget(d.fd);
551 	if (!file)
552 		return -EINVAL;
553 
554 	if (file->f_op != &fuse_dev_operations)
555 		return -EINVAL;
556 
557 	fc = new_conn();
558 	if (!fc)
559 		return -ENOMEM;
560 
561 	fc->flags = d.flags;
562 	fc->user_id = d.user_id;
563 	fc->group_id = d.group_id;
564 	fc->max_read = d.max_read;
565 
566 	/* Used by get_root_inode() */
567 	sb->s_fs_info = fc;
568 
569 	err = -ENOMEM;
570 	root = get_root_inode(sb, d.rootmode);
571 	if (!root)
572 		goto err;
573 
574 	root_dentry = d_alloc_root(root);
575 	if (!root_dentry) {
576 		iput(root);
577 		goto err;
578 	}
579 
580 	init_req = fuse_request_alloc();
581 	if (!init_req)
582 		goto err_put_root;
583 
584 	if (is_bdev) {
585 		fc->destroy_req = fuse_request_alloc();
586 		if (!fc->destroy_req)
587 			goto err_put_root;
588 	}
589 
590 	mutex_lock(&fuse_mutex);
591 	err = -EINVAL;
592 	if (file->private_data)
593 		goto err_unlock;
594 
595 	fc->id = conn_id();
596 	err = fuse_ctl_add_conn(fc);
597 	if (err)
598 		goto err_unlock;
599 
600 	list_add_tail(&fc->entry, &fuse_conn_list);
601 	sb->s_root = root_dentry;
602 	fc->connected = 1;
603 	file->private_data = fuse_conn_get(fc);
604 	mutex_unlock(&fuse_mutex);
605 	/*
606 	 * atomic_dec_and_test() in fput() provides the necessary
607 	 * memory barrier for file->private_data to be visible on all
608 	 * CPUs after this
609 	 */
610 	fput(file);
611 
612 	fuse_send_init(fc, init_req);
613 
614 	return 0;
615 
616  err_unlock:
617 	mutex_unlock(&fuse_mutex);
618 	fuse_request_free(init_req);
619  err_put_root:
620 	dput(root_dentry);
621  err:
622 	fput(file);
623 	fuse_conn_put(fc);
624 	return err;
625 }
626 
627 static int fuse_get_sb(struct file_system_type *fs_type,
628 		       int flags, const char *dev_name,
629 		       void *raw_data, struct vfsmount *mnt)
630 {
631 	return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
632 }
633 
634 static struct file_system_type fuse_fs_type = {
635 	.owner		= THIS_MODULE,
636 	.name		= "fuse",
637 	.get_sb		= fuse_get_sb,
638 	.kill_sb	= kill_anon_super,
639 };
640 
641 #ifdef CONFIG_BLOCK
642 static int fuse_get_sb_blk(struct file_system_type *fs_type,
643 			   int flags, const char *dev_name,
644 			   void *raw_data, struct vfsmount *mnt)
645 {
646 	return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
647 			   mnt);
648 }
649 
650 static struct file_system_type fuseblk_fs_type = {
651 	.owner		= THIS_MODULE,
652 	.name		= "fuseblk",
653 	.get_sb		= fuse_get_sb_blk,
654 	.kill_sb	= kill_block_super,
655 	.fs_flags	= FS_REQUIRES_DEV,
656 };
657 
658 static inline int register_fuseblk(void)
659 {
660 	return register_filesystem(&fuseblk_fs_type);
661 }
662 
663 static inline void unregister_fuseblk(void)
664 {
665 	unregister_filesystem(&fuseblk_fs_type);
666 }
667 #else
668 static inline int register_fuseblk(void)
669 {
670 	return 0;
671 }
672 
673 static inline void unregister_fuseblk(void)
674 {
675 }
676 #endif
677 
678 static decl_subsys(fuse, NULL, NULL);
679 static decl_subsys(connections, NULL, NULL);
680 
681 static void fuse_inode_init_once(void *foo, struct kmem_cache *cachep,
682 				 unsigned long flags)
683 {
684 	struct inode * inode = foo;
685 
686 	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
687 	    SLAB_CTOR_CONSTRUCTOR)
688 		inode_init_once(inode);
689 }
690 
691 static int __init fuse_fs_init(void)
692 {
693 	int err;
694 
695 	err = register_filesystem(&fuse_fs_type);
696 	if (err)
697 		goto out;
698 
699 	err = register_fuseblk();
700 	if (err)
701 		goto out_unreg;
702 
703 	fuse_inode_cachep = kmem_cache_create("fuse_inode",
704 					      sizeof(struct fuse_inode),
705 					      0, SLAB_HWCACHE_ALIGN,
706 					      fuse_inode_init_once, NULL);
707 	err = -ENOMEM;
708 	if (!fuse_inode_cachep)
709 		goto out_unreg2;
710 
711 	return 0;
712 
713  out_unreg2:
714 	unregister_fuseblk();
715  out_unreg:
716 	unregister_filesystem(&fuse_fs_type);
717  out:
718 	return err;
719 }
720 
721 static void fuse_fs_cleanup(void)
722 {
723 	unregister_filesystem(&fuse_fs_type);
724 	unregister_fuseblk();
725 	kmem_cache_destroy(fuse_inode_cachep);
726 }
727 
728 static int fuse_sysfs_init(void)
729 {
730 	int err;
731 
732 	kset_set_kset_s(&fuse_subsys, fs_subsys);
733 	err = subsystem_register(&fuse_subsys);
734 	if (err)
735 		goto out_err;
736 
737 	kset_set_kset_s(&connections_subsys, fuse_subsys);
738 	err = subsystem_register(&connections_subsys);
739 	if (err)
740 		goto out_fuse_unregister;
741 
742 	return 0;
743 
744  out_fuse_unregister:
745 	subsystem_unregister(&fuse_subsys);
746  out_err:
747 	return err;
748 }
749 
750 static void fuse_sysfs_cleanup(void)
751 {
752 	subsystem_unregister(&connections_subsys);
753 	subsystem_unregister(&fuse_subsys);
754 }
755 
756 static int __init fuse_init(void)
757 {
758 	int res;
759 
760 	printk("fuse init (API version %i.%i)\n",
761 	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
762 
763 	INIT_LIST_HEAD(&fuse_conn_list);
764 	res = fuse_fs_init();
765 	if (res)
766 		goto err;
767 
768 	res = fuse_dev_init();
769 	if (res)
770 		goto err_fs_cleanup;
771 
772 	res = fuse_sysfs_init();
773 	if (res)
774 		goto err_dev_cleanup;
775 
776 	res = fuse_ctl_init();
777 	if (res)
778 		goto err_sysfs_cleanup;
779 
780 	return 0;
781 
782  err_sysfs_cleanup:
783 	fuse_sysfs_cleanup();
784  err_dev_cleanup:
785 	fuse_dev_cleanup();
786  err_fs_cleanup:
787 	fuse_fs_cleanup();
788  err:
789 	return res;
790 }
791 
792 static void __exit fuse_exit(void)
793 {
794 	printk(KERN_DEBUG "fuse exit\n");
795 
796 	fuse_ctl_cleanup();
797 	fuse_sysfs_cleanup();
798 	fuse_fs_cleanup();
799 	fuse_dev_cleanup();
800 }
801 
802 module_init(fuse_init);
803 module_exit(fuse_exit);
804