xref: /linux/fs/fuse/inode.c (revision a3a4a816b4b194c45d0217e8b9e08b2639802cda)
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2008  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/moduleparam.h>
18 #include <linux/parser.h>
19 #include <linux/statfs.h>
20 #include <linux/random.h>
21 #include <linux/sched.h>
22 #include <linux/exportfs.h>
23 #include <linux/posix_acl.h>
24 
25 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
26 MODULE_DESCRIPTION("Filesystem in Userspace");
27 MODULE_LICENSE("GPL");
28 
29 static struct kmem_cache *fuse_inode_cachep;
30 struct list_head fuse_conn_list;
31 DEFINE_MUTEX(fuse_mutex);
32 
33 static int set_global_limit(const char *val, struct kernel_param *kp);
34 
35 unsigned max_user_bgreq;
36 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
37 		  &max_user_bgreq, 0644);
38 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
39 MODULE_PARM_DESC(max_user_bgreq,
40  "Global limit for the maximum number of backgrounded requests an "
41  "unprivileged user can set");
42 
43 unsigned max_user_congthresh;
44 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
45 		  &max_user_congthresh, 0644);
46 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
47 MODULE_PARM_DESC(max_user_congthresh,
48  "Global limit for the maximum congestion threshold an "
49  "unprivileged user can set");
50 
51 #define FUSE_SUPER_MAGIC 0x65735546
52 
53 #define FUSE_DEFAULT_BLKSIZE 512
54 
55 /** Maximum number of outstanding background requests */
56 #define FUSE_DEFAULT_MAX_BACKGROUND 12
57 
58 /** Congestion starts at 75% of maximum */
59 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
60 
61 struct fuse_mount_data {
62 	int fd;
63 	unsigned rootmode;
64 	kuid_t user_id;
65 	kgid_t group_id;
66 	unsigned fd_present:1;
67 	unsigned rootmode_present:1;
68 	unsigned user_id_present:1;
69 	unsigned group_id_present:1;
70 	unsigned default_permissions:1;
71 	unsigned allow_other:1;
72 	unsigned max_read;
73 	unsigned blksize;
74 };
75 
76 struct fuse_forget_link *fuse_alloc_forget(void)
77 {
78 	return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
79 }
80 
81 static struct inode *fuse_alloc_inode(struct super_block *sb)
82 {
83 	struct inode *inode;
84 	struct fuse_inode *fi;
85 
86 	inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
87 	if (!inode)
88 		return NULL;
89 
90 	fi = get_fuse_inode(inode);
91 	fi->i_time = 0;
92 	fi->nodeid = 0;
93 	fi->nlookup = 0;
94 	fi->attr_version = 0;
95 	fi->writectr = 0;
96 	fi->orig_ino = 0;
97 	fi->state = 0;
98 	INIT_LIST_HEAD(&fi->write_files);
99 	INIT_LIST_HEAD(&fi->queued_writes);
100 	INIT_LIST_HEAD(&fi->writepages);
101 	init_waitqueue_head(&fi->page_waitq);
102 	mutex_init(&fi->mutex);
103 	fi->forget = fuse_alloc_forget();
104 	if (!fi->forget) {
105 		kmem_cache_free(fuse_inode_cachep, inode);
106 		return NULL;
107 	}
108 
109 	return inode;
110 }
111 
112 static void fuse_i_callback(struct rcu_head *head)
113 {
114 	struct inode *inode = container_of(head, struct inode, i_rcu);
115 	kmem_cache_free(fuse_inode_cachep, inode);
116 }
117 
118 static void fuse_destroy_inode(struct inode *inode)
119 {
120 	struct fuse_inode *fi = get_fuse_inode(inode);
121 	BUG_ON(!list_empty(&fi->write_files));
122 	BUG_ON(!list_empty(&fi->queued_writes));
123 	mutex_destroy(&fi->mutex);
124 	kfree(fi->forget);
125 	call_rcu(&inode->i_rcu, fuse_i_callback);
126 }
127 
128 static void fuse_evict_inode(struct inode *inode)
129 {
130 	truncate_inode_pages_final(&inode->i_data);
131 	clear_inode(inode);
132 	if (inode->i_sb->s_flags & MS_ACTIVE) {
133 		struct fuse_conn *fc = get_fuse_conn(inode);
134 		struct fuse_inode *fi = get_fuse_inode(inode);
135 		fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
136 		fi->forget = NULL;
137 	}
138 }
139 
140 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
141 {
142 	sync_filesystem(sb);
143 	if (*flags & MS_MANDLOCK)
144 		return -EINVAL;
145 
146 	return 0;
147 }
148 
149 /*
150  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
151  * so that it will fit.
152  */
153 static ino_t fuse_squash_ino(u64 ino64)
154 {
155 	ino_t ino = (ino_t) ino64;
156 	if (sizeof(ino_t) < sizeof(u64))
157 		ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
158 	return ino;
159 }
160 
161 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
162 				   u64 attr_valid)
163 {
164 	struct fuse_conn *fc = get_fuse_conn(inode);
165 	struct fuse_inode *fi = get_fuse_inode(inode);
166 
167 	fi->attr_version = ++fc->attr_version;
168 	fi->i_time = attr_valid;
169 
170 	inode->i_ino     = fuse_squash_ino(attr->ino);
171 	inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
172 	set_nlink(inode, attr->nlink);
173 	inode->i_uid     = make_kuid(&init_user_ns, attr->uid);
174 	inode->i_gid     = make_kgid(&init_user_ns, attr->gid);
175 	inode->i_blocks  = attr->blocks;
176 	inode->i_atime.tv_sec   = attr->atime;
177 	inode->i_atime.tv_nsec  = attr->atimensec;
178 	/* mtime from server may be stale due to local buffered write */
179 	if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
180 		inode->i_mtime.tv_sec   = attr->mtime;
181 		inode->i_mtime.tv_nsec  = attr->mtimensec;
182 		inode->i_ctime.tv_sec   = attr->ctime;
183 		inode->i_ctime.tv_nsec  = attr->ctimensec;
184 	}
185 
186 	if (attr->blksize != 0)
187 		inode->i_blkbits = ilog2(attr->blksize);
188 	else
189 		inode->i_blkbits = inode->i_sb->s_blocksize_bits;
190 
191 	/*
192 	 * Don't set the sticky bit in i_mode, unless we want the VFS
193 	 * to check permissions.  This prevents failures due to the
194 	 * check in may_delete().
195 	 */
196 	fi->orig_i_mode = inode->i_mode;
197 	if (!fc->default_permissions)
198 		inode->i_mode &= ~S_ISVTX;
199 
200 	fi->orig_ino = attr->ino;
201 }
202 
203 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
204 			    u64 attr_valid, u64 attr_version)
205 {
206 	struct fuse_conn *fc = get_fuse_conn(inode);
207 	struct fuse_inode *fi = get_fuse_inode(inode);
208 	bool is_wb = fc->writeback_cache;
209 	loff_t oldsize;
210 	struct timespec old_mtime;
211 
212 	spin_lock(&fc->lock);
213 	if ((attr_version != 0 && fi->attr_version > attr_version) ||
214 	    test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
215 		spin_unlock(&fc->lock);
216 		return;
217 	}
218 
219 	old_mtime = inode->i_mtime;
220 	fuse_change_attributes_common(inode, attr, attr_valid);
221 
222 	oldsize = inode->i_size;
223 	/*
224 	 * In case of writeback_cache enabled, the cached writes beyond EOF
225 	 * extend local i_size without keeping userspace server in sync. So,
226 	 * attr->size coming from server can be stale. We cannot trust it.
227 	 */
228 	if (!is_wb || !S_ISREG(inode->i_mode))
229 		i_size_write(inode, attr->size);
230 	spin_unlock(&fc->lock);
231 
232 	if (!is_wb && S_ISREG(inode->i_mode)) {
233 		bool inval = false;
234 
235 		if (oldsize != attr->size) {
236 			truncate_pagecache(inode, attr->size);
237 			inval = true;
238 		} else if (fc->auto_inval_data) {
239 			struct timespec new_mtime = {
240 				.tv_sec = attr->mtime,
241 				.tv_nsec = attr->mtimensec,
242 			};
243 
244 			/*
245 			 * Auto inval mode also checks and invalidates if mtime
246 			 * has changed.
247 			 */
248 			if (!timespec_equal(&old_mtime, &new_mtime))
249 				inval = true;
250 		}
251 
252 		if (inval)
253 			invalidate_inode_pages2(inode->i_mapping);
254 	}
255 }
256 
257 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
258 {
259 	inode->i_mode = attr->mode & S_IFMT;
260 	inode->i_size = attr->size;
261 	inode->i_mtime.tv_sec  = attr->mtime;
262 	inode->i_mtime.tv_nsec = attr->mtimensec;
263 	inode->i_ctime.tv_sec  = attr->ctime;
264 	inode->i_ctime.tv_nsec = attr->ctimensec;
265 	if (S_ISREG(inode->i_mode)) {
266 		fuse_init_common(inode);
267 		fuse_init_file_inode(inode);
268 	} else if (S_ISDIR(inode->i_mode))
269 		fuse_init_dir(inode);
270 	else if (S_ISLNK(inode->i_mode))
271 		fuse_init_symlink(inode);
272 	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
273 		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
274 		fuse_init_common(inode);
275 		init_special_inode(inode, inode->i_mode,
276 				   new_decode_dev(attr->rdev));
277 	} else
278 		BUG();
279 }
280 
281 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
282 {
283 	u64 nodeid = *(u64 *) _nodeidp;
284 	if (get_node_id(inode) == nodeid)
285 		return 1;
286 	else
287 		return 0;
288 }
289 
290 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
291 {
292 	u64 nodeid = *(u64 *) _nodeidp;
293 	get_fuse_inode(inode)->nodeid = nodeid;
294 	return 0;
295 }
296 
297 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
298 			int generation, struct fuse_attr *attr,
299 			u64 attr_valid, u64 attr_version)
300 {
301 	struct inode *inode;
302 	struct fuse_inode *fi;
303 	struct fuse_conn *fc = get_fuse_conn_super(sb);
304 
305  retry:
306 	inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
307 	if (!inode)
308 		return NULL;
309 
310 	if ((inode->i_state & I_NEW)) {
311 		inode->i_flags |= S_NOATIME;
312 		if (!fc->writeback_cache || !S_ISREG(attr->mode))
313 			inode->i_flags |= S_NOCMTIME;
314 		inode->i_generation = generation;
315 		fuse_init_inode(inode, attr);
316 		unlock_new_inode(inode);
317 	} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
318 		/* Inode has changed type, any I/O on the old should fail */
319 		make_bad_inode(inode);
320 		iput(inode);
321 		goto retry;
322 	}
323 
324 	fi = get_fuse_inode(inode);
325 	spin_lock(&fc->lock);
326 	fi->nlookup++;
327 	spin_unlock(&fc->lock);
328 	fuse_change_attributes(inode, attr, attr_valid, attr_version);
329 
330 	return inode;
331 }
332 
333 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
334 			     loff_t offset, loff_t len)
335 {
336 	struct inode *inode;
337 	pgoff_t pg_start;
338 	pgoff_t pg_end;
339 
340 	inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
341 	if (!inode)
342 		return -ENOENT;
343 
344 	fuse_invalidate_attr(inode);
345 	forget_all_cached_acls(inode);
346 	if (offset >= 0) {
347 		pg_start = offset >> PAGE_SHIFT;
348 		if (len <= 0)
349 			pg_end = -1;
350 		else
351 			pg_end = (offset + len - 1) >> PAGE_SHIFT;
352 		invalidate_inode_pages2_range(inode->i_mapping,
353 					      pg_start, pg_end);
354 	}
355 	iput(inode);
356 	return 0;
357 }
358 
359 void fuse_lock_inode(struct inode *inode)
360 {
361 	if (!get_fuse_conn(inode)->parallel_dirops)
362 		mutex_lock(&get_fuse_inode(inode)->mutex);
363 }
364 
365 void fuse_unlock_inode(struct inode *inode)
366 {
367 	if (!get_fuse_conn(inode)->parallel_dirops)
368 		mutex_unlock(&get_fuse_inode(inode)->mutex);
369 }
370 
371 static void fuse_umount_begin(struct super_block *sb)
372 {
373 	fuse_abort_conn(get_fuse_conn_super(sb));
374 }
375 
376 static void fuse_send_destroy(struct fuse_conn *fc)
377 {
378 	struct fuse_req *req = fc->destroy_req;
379 	if (req && fc->conn_init) {
380 		fc->destroy_req = NULL;
381 		req->in.h.opcode = FUSE_DESTROY;
382 		__set_bit(FR_FORCE, &req->flags);
383 		__clear_bit(FR_BACKGROUND, &req->flags);
384 		fuse_request_send(fc, req);
385 		fuse_put_request(fc, req);
386 	}
387 }
388 
389 static void fuse_bdi_destroy(struct fuse_conn *fc)
390 {
391 	if (fc->bdi_initialized)
392 		bdi_destroy(&fc->bdi);
393 }
394 
395 static void fuse_put_super(struct super_block *sb)
396 {
397 	struct fuse_conn *fc = get_fuse_conn_super(sb);
398 
399 	fuse_send_destroy(fc);
400 
401 	fuse_abort_conn(fc);
402 	mutex_lock(&fuse_mutex);
403 	list_del(&fc->entry);
404 	fuse_ctl_remove_conn(fc);
405 	mutex_unlock(&fuse_mutex);
406 	fuse_bdi_destroy(fc);
407 
408 	fuse_conn_put(fc);
409 }
410 
411 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
412 {
413 	stbuf->f_type    = FUSE_SUPER_MAGIC;
414 	stbuf->f_bsize   = attr->bsize;
415 	stbuf->f_frsize  = attr->frsize;
416 	stbuf->f_blocks  = attr->blocks;
417 	stbuf->f_bfree   = attr->bfree;
418 	stbuf->f_bavail  = attr->bavail;
419 	stbuf->f_files   = attr->files;
420 	stbuf->f_ffree   = attr->ffree;
421 	stbuf->f_namelen = attr->namelen;
422 	/* fsid is left zero */
423 }
424 
425 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
426 {
427 	struct super_block *sb = dentry->d_sb;
428 	struct fuse_conn *fc = get_fuse_conn_super(sb);
429 	FUSE_ARGS(args);
430 	struct fuse_statfs_out outarg;
431 	int err;
432 
433 	if (!fuse_allow_current_process(fc)) {
434 		buf->f_type = FUSE_SUPER_MAGIC;
435 		return 0;
436 	}
437 
438 	memset(&outarg, 0, sizeof(outarg));
439 	args.in.numargs = 0;
440 	args.in.h.opcode = FUSE_STATFS;
441 	args.in.h.nodeid = get_node_id(d_inode(dentry));
442 	args.out.numargs = 1;
443 	args.out.args[0].size = sizeof(outarg);
444 	args.out.args[0].value = &outarg;
445 	err = fuse_simple_request(fc, &args);
446 	if (!err)
447 		convert_fuse_statfs(buf, &outarg.st);
448 	return err;
449 }
450 
451 enum {
452 	OPT_FD,
453 	OPT_ROOTMODE,
454 	OPT_USER_ID,
455 	OPT_GROUP_ID,
456 	OPT_DEFAULT_PERMISSIONS,
457 	OPT_ALLOW_OTHER,
458 	OPT_MAX_READ,
459 	OPT_BLKSIZE,
460 	OPT_ERR
461 };
462 
463 static const match_table_t tokens = {
464 	{OPT_FD,			"fd=%u"},
465 	{OPT_ROOTMODE,			"rootmode=%o"},
466 	{OPT_USER_ID,			"user_id=%u"},
467 	{OPT_GROUP_ID,			"group_id=%u"},
468 	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
469 	{OPT_ALLOW_OTHER,		"allow_other"},
470 	{OPT_MAX_READ,			"max_read=%u"},
471 	{OPT_BLKSIZE,			"blksize=%u"},
472 	{OPT_ERR,			NULL}
473 };
474 
475 static int fuse_match_uint(substring_t *s, unsigned int *res)
476 {
477 	int err = -ENOMEM;
478 	char *buf = match_strdup(s);
479 	if (buf) {
480 		err = kstrtouint(buf, 10, res);
481 		kfree(buf);
482 	}
483 	return err;
484 }
485 
486 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
487 {
488 	char *p;
489 	memset(d, 0, sizeof(struct fuse_mount_data));
490 	d->max_read = ~0;
491 	d->blksize = FUSE_DEFAULT_BLKSIZE;
492 
493 	while ((p = strsep(&opt, ",")) != NULL) {
494 		int token;
495 		int value;
496 		unsigned uv;
497 		substring_t args[MAX_OPT_ARGS];
498 		if (!*p)
499 			continue;
500 
501 		token = match_token(p, tokens, args);
502 		switch (token) {
503 		case OPT_FD:
504 			if (match_int(&args[0], &value))
505 				return 0;
506 			d->fd = value;
507 			d->fd_present = 1;
508 			break;
509 
510 		case OPT_ROOTMODE:
511 			if (match_octal(&args[0], &value))
512 				return 0;
513 			if (!fuse_valid_type(value))
514 				return 0;
515 			d->rootmode = value;
516 			d->rootmode_present = 1;
517 			break;
518 
519 		case OPT_USER_ID:
520 			if (fuse_match_uint(&args[0], &uv))
521 				return 0;
522 			d->user_id = make_kuid(current_user_ns(), uv);
523 			if (!uid_valid(d->user_id))
524 				return 0;
525 			d->user_id_present = 1;
526 			break;
527 
528 		case OPT_GROUP_ID:
529 			if (fuse_match_uint(&args[0], &uv))
530 				return 0;
531 			d->group_id = make_kgid(current_user_ns(), uv);
532 			if (!gid_valid(d->group_id))
533 				return 0;
534 			d->group_id_present = 1;
535 			break;
536 
537 		case OPT_DEFAULT_PERMISSIONS:
538 			d->default_permissions = 1;
539 			break;
540 
541 		case OPT_ALLOW_OTHER:
542 			d->allow_other = 1;
543 			break;
544 
545 		case OPT_MAX_READ:
546 			if (match_int(&args[0], &value))
547 				return 0;
548 			d->max_read = value;
549 			break;
550 
551 		case OPT_BLKSIZE:
552 			if (!is_bdev || match_int(&args[0], &value))
553 				return 0;
554 			d->blksize = value;
555 			break;
556 
557 		default:
558 			return 0;
559 		}
560 	}
561 
562 	if (!d->fd_present || !d->rootmode_present ||
563 	    !d->user_id_present || !d->group_id_present)
564 		return 0;
565 
566 	return 1;
567 }
568 
569 static int fuse_show_options(struct seq_file *m, struct dentry *root)
570 {
571 	struct super_block *sb = root->d_sb;
572 	struct fuse_conn *fc = get_fuse_conn_super(sb);
573 
574 	seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
575 	seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
576 	if (fc->default_permissions)
577 		seq_puts(m, ",default_permissions");
578 	if (fc->allow_other)
579 		seq_puts(m, ",allow_other");
580 	if (fc->max_read != ~0)
581 		seq_printf(m, ",max_read=%u", fc->max_read);
582 	if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
583 		seq_printf(m, ",blksize=%lu", sb->s_blocksize);
584 	return 0;
585 }
586 
587 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
588 {
589 	memset(fiq, 0, sizeof(struct fuse_iqueue));
590 	init_waitqueue_head(&fiq->waitq);
591 	INIT_LIST_HEAD(&fiq->pending);
592 	INIT_LIST_HEAD(&fiq->interrupts);
593 	fiq->forget_list_tail = &fiq->forget_list_head;
594 	fiq->connected = 1;
595 }
596 
597 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
598 {
599 	memset(fpq, 0, sizeof(struct fuse_pqueue));
600 	spin_lock_init(&fpq->lock);
601 	INIT_LIST_HEAD(&fpq->processing);
602 	INIT_LIST_HEAD(&fpq->io);
603 	fpq->connected = 1;
604 }
605 
606 void fuse_conn_init(struct fuse_conn *fc)
607 {
608 	memset(fc, 0, sizeof(*fc));
609 	spin_lock_init(&fc->lock);
610 	init_rwsem(&fc->killsb);
611 	atomic_set(&fc->count, 1);
612 	atomic_set(&fc->dev_count, 1);
613 	init_waitqueue_head(&fc->blocked_waitq);
614 	init_waitqueue_head(&fc->reserved_req_waitq);
615 	fuse_iqueue_init(&fc->iq);
616 	INIT_LIST_HEAD(&fc->bg_queue);
617 	INIT_LIST_HEAD(&fc->entry);
618 	INIT_LIST_HEAD(&fc->devices);
619 	atomic_set(&fc->num_waiting, 0);
620 	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
621 	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
622 	fc->khctr = 0;
623 	fc->polled_files = RB_ROOT;
624 	fc->blocked = 0;
625 	fc->initialized = 0;
626 	fc->connected = 1;
627 	fc->attr_version = 1;
628 	get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
629 }
630 EXPORT_SYMBOL_GPL(fuse_conn_init);
631 
632 void fuse_conn_put(struct fuse_conn *fc)
633 {
634 	if (atomic_dec_and_test(&fc->count)) {
635 		if (fc->destroy_req)
636 			fuse_request_free(fc->destroy_req);
637 		fc->release(fc);
638 	}
639 }
640 EXPORT_SYMBOL_GPL(fuse_conn_put);
641 
642 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
643 {
644 	atomic_inc(&fc->count);
645 	return fc;
646 }
647 EXPORT_SYMBOL_GPL(fuse_conn_get);
648 
649 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
650 {
651 	struct fuse_attr attr;
652 	memset(&attr, 0, sizeof(attr));
653 
654 	attr.mode = mode;
655 	attr.ino = FUSE_ROOT_ID;
656 	attr.nlink = 1;
657 	return fuse_iget(sb, 1, 0, &attr, 0, 0);
658 }
659 
660 struct fuse_inode_handle {
661 	u64 nodeid;
662 	u32 generation;
663 };
664 
665 static struct dentry *fuse_get_dentry(struct super_block *sb,
666 				      struct fuse_inode_handle *handle)
667 {
668 	struct fuse_conn *fc = get_fuse_conn_super(sb);
669 	struct inode *inode;
670 	struct dentry *entry;
671 	int err = -ESTALE;
672 
673 	if (handle->nodeid == 0)
674 		goto out_err;
675 
676 	inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
677 	if (!inode) {
678 		struct fuse_entry_out outarg;
679 		const struct qstr name = QSTR_INIT(".", 1);
680 
681 		if (!fc->export_support)
682 			goto out_err;
683 
684 		err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
685 				       &inode);
686 		if (err && err != -ENOENT)
687 			goto out_err;
688 		if (err || !inode) {
689 			err = -ESTALE;
690 			goto out_err;
691 		}
692 		err = -EIO;
693 		if (get_node_id(inode) != handle->nodeid)
694 			goto out_iput;
695 	}
696 	err = -ESTALE;
697 	if (inode->i_generation != handle->generation)
698 		goto out_iput;
699 
700 	entry = d_obtain_alias(inode);
701 	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
702 		fuse_invalidate_entry_cache(entry);
703 
704 	return entry;
705 
706  out_iput:
707 	iput(inode);
708  out_err:
709 	return ERR_PTR(err);
710 }
711 
712 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
713 			   struct inode *parent)
714 {
715 	int len = parent ? 6 : 3;
716 	u64 nodeid;
717 	u32 generation;
718 
719 	if (*max_len < len) {
720 		*max_len = len;
721 		return  FILEID_INVALID;
722 	}
723 
724 	nodeid = get_fuse_inode(inode)->nodeid;
725 	generation = inode->i_generation;
726 
727 	fh[0] = (u32)(nodeid >> 32);
728 	fh[1] = (u32)(nodeid & 0xffffffff);
729 	fh[2] = generation;
730 
731 	if (parent) {
732 		nodeid = get_fuse_inode(parent)->nodeid;
733 		generation = parent->i_generation;
734 
735 		fh[3] = (u32)(nodeid >> 32);
736 		fh[4] = (u32)(nodeid & 0xffffffff);
737 		fh[5] = generation;
738 	}
739 
740 	*max_len = len;
741 	return parent ? 0x82 : 0x81;
742 }
743 
744 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
745 		struct fid *fid, int fh_len, int fh_type)
746 {
747 	struct fuse_inode_handle handle;
748 
749 	if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
750 		return NULL;
751 
752 	handle.nodeid = (u64) fid->raw[0] << 32;
753 	handle.nodeid |= (u64) fid->raw[1];
754 	handle.generation = fid->raw[2];
755 	return fuse_get_dentry(sb, &handle);
756 }
757 
758 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
759 		struct fid *fid, int fh_len, int fh_type)
760 {
761 	struct fuse_inode_handle parent;
762 
763 	if (fh_type != 0x82 || fh_len < 6)
764 		return NULL;
765 
766 	parent.nodeid = (u64) fid->raw[3] << 32;
767 	parent.nodeid |= (u64) fid->raw[4];
768 	parent.generation = fid->raw[5];
769 	return fuse_get_dentry(sb, &parent);
770 }
771 
772 static struct dentry *fuse_get_parent(struct dentry *child)
773 {
774 	struct inode *child_inode = d_inode(child);
775 	struct fuse_conn *fc = get_fuse_conn(child_inode);
776 	struct inode *inode;
777 	struct dentry *parent;
778 	struct fuse_entry_out outarg;
779 	const struct qstr name = QSTR_INIT("..", 2);
780 	int err;
781 
782 	if (!fc->export_support)
783 		return ERR_PTR(-ESTALE);
784 
785 	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
786 			       &name, &outarg, &inode);
787 	if (err) {
788 		if (err == -ENOENT)
789 			return ERR_PTR(-ESTALE);
790 		return ERR_PTR(err);
791 	}
792 
793 	parent = d_obtain_alias(inode);
794 	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
795 		fuse_invalidate_entry_cache(parent);
796 
797 	return parent;
798 }
799 
800 static const struct export_operations fuse_export_operations = {
801 	.fh_to_dentry	= fuse_fh_to_dentry,
802 	.fh_to_parent	= fuse_fh_to_parent,
803 	.encode_fh	= fuse_encode_fh,
804 	.get_parent	= fuse_get_parent,
805 };
806 
807 static const struct super_operations fuse_super_operations = {
808 	.alloc_inode    = fuse_alloc_inode,
809 	.destroy_inode  = fuse_destroy_inode,
810 	.evict_inode	= fuse_evict_inode,
811 	.write_inode	= fuse_write_inode,
812 	.drop_inode	= generic_delete_inode,
813 	.remount_fs	= fuse_remount_fs,
814 	.put_super	= fuse_put_super,
815 	.umount_begin	= fuse_umount_begin,
816 	.statfs		= fuse_statfs,
817 	.show_options	= fuse_show_options,
818 };
819 
820 static void sanitize_global_limit(unsigned *limit)
821 {
822 	if (*limit == 0)
823 		*limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
824 			 sizeof(struct fuse_req);
825 
826 	if (*limit >= 1 << 16)
827 		*limit = (1 << 16) - 1;
828 }
829 
830 static int set_global_limit(const char *val, struct kernel_param *kp)
831 {
832 	int rv;
833 
834 	rv = param_set_uint(val, kp);
835 	if (rv)
836 		return rv;
837 
838 	sanitize_global_limit((unsigned *)kp->arg);
839 
840 	return 0;
841 }
842 
843 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
844 {
845 	int cap_sys_admin = capable(CAP_SYS_ADMIN);
846 
847 	if (arg->minor < 13)
848 		return;
849 
850 	sanitize_global_limit(&max_user_bgreq);
851 	sanitize_global_limit(&max_user_congthresh);
852 
853 	if (arg->max_background) {
854 		fc->max_background = arg->max_background;
855 
856 		if (!cap_sys_admin && fc->max_background > max_user_bgreq)
857 			fc->max_background = max_user_bgreq;
858 	}
859 	if (arg->congestion_threshold) {
860 		fc->congestion_threshold = arg->congestion_threshold;
861 
862 		if (!cap_sys_admin &&
863 		    fc->congestion_threshold > max_user_congthresh)
864 			fc->congestion_threshold = max_user_congthresh;
865 	}
866 }
867 
868 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
869 {
870 	struct fuse_init_out *arg = &req->misc.init_out;
871 
872 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
873 		fc->conn_error = 1;
874 	else {
875 		unsigned long ra_pages;
876 
877 		process_init_limits(fc, arg);
878 
879 		if (arg->minor >= 6) {
880 			ra_pages = arg->max_readahead / PAGE_SIZE;
881 			if (arg->flags & FUSE_ASYNC_READ)
882 				fc->async_read = 1;
883 			if (!(arg->flags & FUSE_POSIX_LOCKS))
884 				fc->no_lock = 1;
885 			if (arg->minor >= 17) {
886 				if (!(arg->flags & FUSE_FLOCK_LOCKS))
887 					fc->no_flock = 1;
888 			} else {
889 				if (!(arg->flags & FUSE_POSIX_LOCKS))
890 					fc->no_flock = 1;
891 			}
892 			if (arg->flags & FUSE_ATOMIC_O_TRUNC)
893 				fc->atomic_o_trunc = 1;
894 			if (arg->minor >= 9) {
895 				/* LOOKUP has dependency on proto version */
896 				if (arg->flags & FUSE_EXPORT_SUPPORT)
897 					fc->export_support = 1;
898 			}
899 			if (arg->flags & FUSE_BIG_WRITES)
900 				fc->big_writes = 1;
901 			if (arg->flags & FUSE_DONT_MASK)
902 				fc->dont_mask = 1;
903 			if (arg->flags & FUSE_AUTO_INVAL_DATA)
904 				fc->auto_inval_data = 1;
905 			if (arg->flags & FUSE_DO_READDIRPLUS) {
906 				fc->do_readdirplus = 1;
907 				if (arg->flags & FUSE_READDIRPLUS_AUTO)
908 					fc->readdirplus_auto = 1;
909 			}
910 			if (arg->flags & FUSE_ASYNC_DIO)
911 				fc->async_dio = 1;
912 			if (arg->flags & FUSE_WRITEBACK_CACHE)
913 				fc->writeback_cache = 1;
914 			if (arg->flags & FUSE_PARALLEL_DIROPS)
915 				fc->parallel_dirops = 1;
916 			if (arg->flags & FUSE_HANDLE_KILLPRIV)
917 				fc->handle_killpriv = 1;
918 			if (arg->time_gran && arg->time_gran <= 1000000000)
919 				fc->sb->s_time_gran = arg->time_gran;
920 			if ((arg->flags & FUSE_POSIX_ACL)) {
921 				fc->default_permissions = 1;
922 				fc->posix_acl = 1;
923 				fc->sb->s_xattr = fuse_acl_xattr_handlers;
924 			}
925 		} else {
926 			ra_pages = fc->max_read / PAGE_SIZE;
927 			fc->no_lock = 1;
928 			fc->no_flock = 1;
929 		}
930 
931 		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
932 		fc->minor = arg->minor;
933 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
934 		fc->max_write = max_t(unsigned, 4096, fc->max_write);
935 		fc->conn_init = 1;
936 	}
937 	fuse_set_initialized(fc);
938 	wake_up_all(&fc->blocked_waitq);
939 }
940 
941 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
942 {
943 	struct fuse_init_in *arg = &req->misc.init_in;
944 
945 	arg->major = FUSE_KERNEL_VERSION;
946 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
947 	arg->max_readahead = fc->bdi.ra_pages * PAGE_SIZE;
948 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
949 		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
950 		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
951 		FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
952 		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
953 		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
954 		FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL;
955 	req->in.h.opcode = FUSE_INIT;
956 	req->in.numargs = 1;
957 	req->in.args[0].size = sizeof(*arg);
958 	req->in.args[0].value = arg;
959 	req->out.numargs = 1;
960 	/* Variable length argument used for backward compatibility
961 	   with interface version < 7.5.  Rest of init_out is zeroed
962 	   by do_get_request(), so a short reply is not a problem */
963 	req->out.argvar = 1;
964 	req->out.args[0].size = sizeof(struct fuse_init_out);
965 	req->out.args[0].value = &req->misc.init_out;
966 	req->end = process_init_reply;
967 	fuse_request_send_background(fc, req);
968 }
969 
970 static void fuse_free_conn(struct fuse_conn *fc)
971 {
972 	WARN_ON(!list_empty(&fc->devices));
973 	kfree_rcu(fc, rcu);
974 }
975 
976 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
977 {
978 	int err;
979 
980 	fc->bdi.name = "fuse";
981 	fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
982 	/* fuse does it's own writeback accounting */
983 	fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
984 
985 	err = bdi_init(&fc->bdi);
986 	if (err)
987 		return err;
988 
989 	fc->bdi_initialized = 1;
990 
991 	if (sb->s_bdev) {
992 		err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
993 				    MAJOR(fc->dev), MINOR(fc->dev));
994 	} else {
995 		err = bdi_register_dev(&fc->bdi, fc->dev);
996 	}
997 
998 	if (err)
999 		return err;
1000 
1001 	/*
1002 	 * For a single fuse filesystem use max 1% of dirty +
1003 	 * writeback threshold.
1004 	 *
1005 	 * This gives about 1M of write buffer for memory maps on a
1006 	 * machine with 1G and 10% dirty_ratio, which should be more
1007 	 * than enough.
1008 	 *
1009 	 * Privileged users can raise it by writing to
1010 	 *
1011 	 *    /sys/class/bdi/<bdi>/max_ratio
1012 	 */
1013 	bdi_set_max_ratio(&fc->bdi, 1);
1014 
1015 	return 0;
1016 }
1017 
1018 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1019 {
1020 	struct fuse_dev *fud;
1021 
1022 	fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1023 	if (fud) {
1024 		fud->fc = fuse_conn_get(fc);
1025 		fuse_pqueue_init(&fud->pq);
1026 
1027 		spin_lock(&fc->lock);
1028 		list_add_tail(&fud->entry, &fc->devices);
1029 		spin_unlock(&fc->lock);
1030 	}
1031 
1032 	return fud;
1033 }
1034 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1035 
1036 void fuse_dev_free(struct fuse_dev *fud)
1037 {
1038 	struct fuse_conn *fc = fud->fc;
1039 
1040 	if (fc) {
1041 		spin_lock(&fc->lock);
1042 		list_del(&fud->entry);
1043 		spin_unlock(&fc->lock);
1044 
1045 		fuse_conn_put(fc);
1046 	}
1047 	kfree(fud);
1048 }
1049 EXPORT_SYMBOL_GPL(fuse_dev_free);
1050 
1051 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1052 {
1053 	struct fuse_dev *fud;
1054 	struct fuse_conn *fc;
1055 	struct inode *root;
1056 	struct fuse_mount_data d;
1057 	struct file *file;
1058 	struct dentry *root_dentry;
1059 	struct fuse_req *init_req;
1060 	int err;
1061 	int is_bdev = sb->s_bdev != NULL;
1062 
1063 	err = -EINVAL;
1064 	if (sb->s_flags & MS_MANDLOCK)
1065 		goto err;
1066 
1067 	sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION);
1068 
1069 	if (!parse_fuse_opt(data, &d, is_bdev))
1070 		goto err;
1071 
1072 	if (is_bdev) {
1073 #ifdef CONFIG_BLOCK
1074 		err = -EINVAL;
1075 		if (!sb_set_blocksize(sb, d.blksize))
1076 			goto err;
1077 #endif
1078 	} else {
1079 		sb->s_blocksize = PAGE_SIZE;
1080 		sb->s_blocksize_bits = PAGE_SHIFT;
1081 	}
1082 	sb->s_magic = FUSE_SUPER_MAGIC;
1083 	sb->s_op = &fuse_super_operations;
1084 	sb->s_xattr = fuse_xattr_handlers;
1085 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1086 	sb->s_time_gran = 1;
1087 	sb->s_export_op = &fuse_export_operations;
1088 
1089 	file = fget(d.fd);
1090 	err = -EINVAL;
1091 	if (!file)
1092 		goto err;
1093 
1094 	if ((file->f_op != &fuse_dev_operations) ||
1095 	    (file->f_cred->user_ns != &init_user_ns))
1096 		goto err_fput;
1097 
1098 	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1099 	err = -ENOMEM;
1100 	if (!fc)
1101 		goto err_fput;
1102 
1103 	fuse_conn_init(fc);
1104 	fc->release = fuse_free_conn;
1105 
1106 	fud = fuse_dev_alloc(fc);
1107 	if (!fud)
1108 		goto err_put_conn;
1109 
1110 	fc->dev = sb->s_dev;
1111 	fc->sb = sb;
1112 	err = fuse_bdi_init(fc, sb);
1113 	if (err)
1114 		goto err_dev_free;
1115 
1116 	sb->s_bdi = &fc->bdi;
1117 
1118 	/* Handle umasking inside the fuse code */
1119 	if (sb->s_flags & MS_POSIXACL)
1120 		fc->dont_mask = 1;
1121 	sb->s_flags |= MS_POSIXACL;
1122 
1123 	fc->default_permissions = d.default_permissions;
1124 	fc->allow_other = d.allow_other;
1125 	fc->user_id = d.user_id;
1126 	fc->group_id = d.group_id;
1127 	fc->max_read = max_t(unsigned, 4096, d.max_read);
1128 
1129 	/* Used by get_root_inode() */
1130 	sb->s_fs_info = fc;
1131 
1132 	err = -ENOMEM;
1133 	root = fuse_get_root_inode(sb, d.rootmode);
1134 	sb->s_d_op = &fuse_root_dentry_operations;
1135 	root_dentry = d_make_root(root);
1136 	if (!root_dentry)
1137 		goto err_dev_free;
1138 	/* Root dentry doesn't have .d_revalidate */
1139 	sb->s_d_op = &fuse_dentry_operations;
1140 
1141 	init_req = fuse_request_alloc(0);
1142 	if (!init_req)
1143 		goto err_put_root;
1144 	__set_bit(FR_BACKGROUND, &init_req->flags);
1145 
1146 	if (is_bdev) {
1147 		fc->destroy_req = fuse_request_alloc(0);
1148 		if (!fc->destroy_req)
1149 			goto err_free_init_req;
1150 	}
1151 
1152 	mutex_lock(&fuse_mutex);
1153 	err = -EINVAL;
1154 	if (file->private_data)
1155 		goto err_unlock;
1156 
1157 	err = fuse_ctl_add_conn(fc);
1158 	if (err)
1159 		goto err_unlock;
1160 
1161 	list_add_tail(&fc->entry, &fuse_conn_list);
1162 	sb->s_root = root_dentry;
1163 	file->private_data = fud;
1164 	mutex_unlock(&fuse_mutex);
1165 	/*
1166 	 * atomic_dec_and_test() in fput() provides the necessary
1167 	 * memory barrier for file->private_data to be visible on all
1168 	 * CPUs after this
1169 	 */
1170 	fput(file);
1171 
1172 	fuse_send_init(fc, init_req);
1173 
1174 	return 0;
1175 
1176  err_unlock:
1177 	mutex_unlock(&fuse_mutex);
1178  err_free_init_req:
1179 	fuse_request_free(init_req);
1180  err_put_root:
1181 	dput(root_dentry);
1182  err_dev_free:
1183 	fuse_dev_free(fud);
1184  err_put_conn:
1185 	fuse_bdi_destroy(fc);
1186 	fuse_conn_put(fc);
1187  err_fput:
1188 	fput(file);
1189  err:
1190 	return err;
1191 }
1192 
1193 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1194 		       int flags, const char *dev_name,
1195 		       void *raw_data)
1196 {
1197 	return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1198 }
1199 
1200 static void fuse_kill_sb_anon(struct super_block *sb)
1201 {
1202 	struct fuse_conn *fc = get_fuse_conn_super(sb);
1203 
1204 	if (fc) {
1205 		down_write(&fc->killsb);
1206 		fc->sb = NULL;
1207 		up_write(&fc->killsb);
1208 	}
1209 
1210 	kill_anon_super(sb);
1211 }
1212 
1213 static struct file_system_type fuse_fs_type = {
1214 	.owner		= THIS_MODULE,
1215 	.name		= "fuse",
1216 	.fs_flags	= FS_HAS_SUBTYPE,
1217 	.mount		= fuse_mount,
1218 	.kill_sb	= fuse_kill_sb_anon,
1219 };
1220 MODULE_ALIAS_FS("fuse");
1221 
1222 #ifdef CONFIG_BLOCK
1223 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1224 			   int flags, const char *dev_name,
1225 			   void *raw_data)
1226 {
1227 	return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1228 }
1229 
1230 static void fuse_kill_sb_blk(struct super_block *sb)
1231 {
1232 	struct fuse_conn *fc = get_fuse_conn_super(sb);
1233 
1234 	if (fc) {
1235 		down_write(&fc->killsb);
1236 		fc->sb = NULL;
1237 		up_write(&fc->killsb);
1238 	}
1239 
1240 	kill_block_super(sb);
1241 }
1242 
1243 static struct file_system_type fuseblk_fs_type = {
1244 	.owner		= THIS_MODULE,
1245 	.name		= "fuseblk",
1246 	.mount		= fuse_mount_blk,
1247 	.kill_sb	= fuse_kill_sb_blk,
1248 	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1249 };
1250 MODULE_ALIAS_FS("fuseblk");
1251 
1252 static inline int register_fuseblk(void)
1253 {
1254 	return register_filesystem(&fuseblk_fs_type);
1255 }
1256 
1257 static inline void unregister_fuseblk(void)
1258 {
1259 	unregister_filesystem(&fuseblk_fs_type);
1260 }
1261 #else
1262 static inline int register_fuseblk(void)
1263 {
1264 	return 0;
1265 }
1266 
1267 static inline void unregister_fuseblk(void)
1268 {
1269 }
1270 #endif
1271 
1272 static void fuse_inode_init_once(void *foo)
1273 {
1274 	struct inode *inode = foo;
1275 
1276 	inode_init_once(inode);
1277 }
1278 
1279 static int __init fuse_fs_init(void)
1280 {
1281 	int err;
1282 
1283 	fuse_inode_cachep = kmem_cache_create("fuse_inode",
1284 					      sizeof(struct fuse_inode), 0,
1285 					      SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
1286 					      fuse_inode_init_once);
1287 	err = -ENOMEM;
1288 	if (!fuse_inode_cachep)
1289 		goto out;
1290 
1291 	err = register_fuseblk();
1292 	if (err)
1293 		goto out2;
1294 
1295 	err = register_filesystem(&fuse_fs_type);
1296 	if (err)
1297 		goto out3;
1298 
1299 	return 0;
1300 
1301  out3:
1302 	unregister_fuseblk();
1303  out2:
1304 	kmem_cache_destroy(fuse_inode_cachep);
1305  out:
1306 	return err;
1307 }
1308 
1309 static void fuse_fs_cleanup(void)
1310 {
1311 	unregister_filesystem(&fuse_fs_type);
1312 	unregister_fuseblk();
1313 
1314 	/*
1315 	 * Make sure all delayed rcu free inodes are flushed before we
1316 	 * destroy cache.
1317 	 */
1318 	rcu_barrier();
1319 	kmem_cache_destroy(fuse_inode_cachep);
1320 }
1321 
1322 static struct kobject *fuse_kobj;
1323 
1324 static int fuse_sysfs_init(void)
1325 {
1326 	int err;
1327 
1328 	fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1329 	if (!fuse_kobj) {
1330 		err = -ENOMEM;
1331 		goto out_err;
1332 	}
1333 
1334 	err = sysfs_create_mount_point(fuse_kobj, "connections");
1335 	if (err)
1336 		goto out_fuse_unregister;
1337 
1338 	return 0;
1339 
1340  out_fuse_unregister:
1341 	kobject_put(fuse_kobj);
1342  out_err:
1343 	return err;
1344 }
1345 
1346 static void fuse_sysfs_cleanup(void)
1347 {
1348 	sysfs_remove_mount_point(fuse_kobj, "connections");
1349 	kobject_put(fuse_kobj);
1350 }
1351 
1352 static int __init fuse_init(void)
1353 {
1354 	int res;
1355 
1356 	printk(KERN_INFO "fuse init (API version %i.%i)\n",
1357 	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1358 
1359 	INIT_LIST_HEAD(&fuse_conn_list);
1360 	res = fuse_fs_init();
1361 	if (res)
1362 		goto err;
1363 
1364 	res = fuse_dev_init();
1365 	if (res)
1366 		goto err_fs_cleanup;
1367 
1368 	res = fuse_sysfs_init();
1369 	if (res)
1370 		goto err_dev_cleanup;
1371 
1372 	res = fuse_ctl_init();
1373 	if (res)
1374 		goto err_sysfs_cleanup;
1375 
1376 	sanitize_global_limit(&max_user_bgreq);
1377 	sanitize_global_limit(&max_user_congthresh);
1378 
1379 	return 0;
1380 
1381  err_sysfs_cleanup:
1382 	fuse_sysfs_cleanup();
1383  err_dev_cleanup:
1384 	fuse_dev_cleanup();
1385  err_fs_cleanup:
1386 	fuse_fs_cleanup();
1387  err:
1388 	return res;
1389 }
1390 
1391 static void __exit fuse_exit(void)
1392 {
1393 	printk(KERN_DEBUG "fuse exit\n");
1394 
1395 	fuse_ctl_cleanup();
1396 	fuse_sysfs_cleanup();
1397 	fuse_fs_cleanup();
1398 	fuse_dev_cleanup();
1399 }
1400 
1401 module_init(fuse_init);
1402 module_exit(fuse_exit);
1403