xref: /linux/fs/fuse/inode.c (revision 74ce1896c6c65b2f8cccbf59162d542988835835)
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 #include <linux/pid_namespace.h>
25 
26 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
27 MODULE_DESCRIPTION("Filesystem in Userspace");
28 MODULE_LICENSE("GPL");
29 
30 static struct kmem_cache *fuse_inode_cachep;
31 struct list_head fuse_conn_list;
32 DEFINE_MUTEX(fuse_mutex);
33 
34 static int set_global_limit(const char *val, struct kernel_param *kp);
35 
36 unsigned max_user_bgreq;
37 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
38 		  &max_user_bgreq, 0644);
39 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
40 MODULE_PARM_DESC(max_user_bgreq,
41  "Global limit for the maximum number of backgrounded requests an "
42  "unprivileged user can set");
43 
44 unsigned max_user_congthresh;
45 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
46 		  &max_user_congthresh, 0644);
47 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
48 MODULE_PARM_DESC(max_user_congthresh,
49  "Global limit for the maximum congestion threshold an "
50  "unprivileged user can set");
51 
52 #define FUSE_SUPER_MAGIC 0x65735546
53 
54 #define FUSE_DEFAULT_BLKSIZE 512
55 
56 /** Maximum number of outstanding background requests */
57 #define FUSE_DEFAULT_MAX_BACKGROUND 12
58 
59 /** Congestion starts at 75% of maximum */
60 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
61 
62 struct fuse_mount_data {
63 	int fd;
64 	unsigned rootmode;
65 	kuid_t user_id;
66 	kgid_t group_id;
67 	unsigned fd_present:1;
68 	unsigned rootmode_present:1;
69 	unsigned user_id_present:1;
70 	unsigned group_id_present:1;
71 	unsigned default_permissions:1;
72 	unsigned allow_other:1;
73 	unsigned max_read;
74 	unsigned blksize;
75 };
76 
77 struct fuse_forget_link *fuse_alloc_forget(void)
78 {
79 	return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
80 }
81 
82 static struct inode *fuse_alloc_inode(struct super_block *sb)
83 {
84 	struct inode *inode;
85 	struct fuse_inode *fi;
86 
87 	inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
88 	if (!inode)
89 		return NULL;
90 
91 	fi = get_fuse_inode(inode);
92 	fi->i_time = 0;
93 	fi->nodeid = 0;
94 	fi->nlookup = 0;
95 	fi->attr_version = 0;
96 	fi->writectr = 0;
97 	fi->orig_ino = 0;
98 	fi->state = 0;
99 	INIT_LIST_HEAD(&fi->write_files);
100 	INIT_LIST_HEAD(&fi->queued_writes);
101 	INIT_LIST_HEAD(&fi->writepages);
102 	init_waitqueue_head(&fi->page_waitq);
103 	mutex_init(&fi->mutex);
104 	fi->forget = fuse_alloc_forget();
105 	if (!fi->forget) {
106 		kmem_cache_free(fuse_inode_cachep, inode);
107 		return NULL;
108 	}
109 
110 	return inode;
111 }
112 
113 static void fuse_i_callback(struct rcu_head *head)
114 {
115 	struct inode *inode = container_of(head, struct inode, i_rcu);
116 	kmem_cache_free(fuse_inode_cachep, inode);
117 }
118 
119 static void fuse_destroy_inode(struct inode *inode)
120 {
121 	struct fuse_inode *fi = get_fuse_inode(inode);
122 	BUG_ON(!list_empty(&fi->write_files));
123 	BUG_ON(!list_empty(&fi->queued_writes));
124 	mutex_destroy(&fi->mutex);
125 	kfree(fi->forget);
126 	call_rcu(&inode->i_rcu, fuse_i_callback);
127 }
128 
129 static void fuse_evict_inode(struct inode *inode)
130 {
131 	truncate_inode_pages_final(&inode->i_data);
132 	clear_inode(inode);
133 	if (inode->i_sb->s_flags & MS_ACTIVE) {
134 		struct fuse_conn *fc = get_fuse_conn(inode);
135 		struct fuse_inode *fi = get_fuse_inode(inode);
136 		fuse_queue_forget(fc, fi->forget, fi->nodeid, fi->nlookup);
137 		fi->forget = NULL;
138 	}
139 }
140 
141 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
142 {
143 	sync_filesystem(sb);
144 	if (*flags & MS_MANDLOCK)
145 		return -EINVAL;
146 
147 	return 0;
148 }
149 
150 /*
151  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
152  * so that it will fit.
153  */
154 static ino_t fuse_squash_ino(u64 ino64)
155 {
156 	ino_t ino = (ino_t) ino64;
157 	if (sizeof(ino_t) < sizeof(u64))
158 		ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
159 	return ino;
160 }
161 
162 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
163 				   u64 attr_valid)
164 {
165 	struct fuse_conn *fc = get_fuse_conn(inode);
166 	struct fuse_inode *fi = get_fuse_inode(inode);
167 
168 	fi->attr_version = ++fc->attr_version;
169 	fi->i_time = attr_valid;
170 
171 	inode->i_ino     = fuse_squash_ino(attr->ino);
172 	inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
173 	set_nlink(inode, attr->nlink);
174 	inode->i_uid     = make_kuid(&init_user_ns, attr->uid);
175 	inode->i_gid     = make_kgid(&init_user_ns, attr->gid);
176 	inode->i_blocks  = attr->blocks;
177 	inode->i_atime.tv_sec   = attr->atime;
178 	inode->i_atime.tv_nsec  = attr->atimensec;
179 	/* mtime from server may be stale due to local buffered write */
180 	if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
181 		inode->i_mtime.tv_sec   = attr->mtime;
182 		inode->i_mtime.tv_nsec  = attr->mtimensec;
183 		inode->i_ctime.tv_sec   = attr->ctime;
184 		inode->i_ctime.tv_nsec  = attr->ctimensec;
185 	}
186 
187 	if (attr->blksize != 0)
188 		inode->i_blkbits = ilog2(attr->blksize);
189 	else
190 		inode->i_blkbits = inode->i_sb->s_blocksize_bits;
191 
192 	/*
193 	 * Don't set the sticky bit in i_mode, unless we want the VFS
194 	 * to check permissions.  This prevents failures due to the
195 	 * check in may_delete().
196 	 */
197 	fi->orig_i_mode = inode->i_mode;
198 	if (!fc->default_permissions)
199 		inode->i_mode &= ~S_ISVTX;
200 
201 	fi->orig_ino = attr->ino;
202 }
203 
204 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
205 			    u64 attr_valid, u64 attr_version)
206 {
207 	struct fuse_conn *fc = get_fuse_conn(inode);
208 	struct fuse_inode *fi = get_fuse_inode(inode);
209 	bool is_wb = fc->writeback_cache;
210 	loff_t oldsize;
211 	struct timespec old_mtime;
212 
213 	spin_lock(&fc->lock);
214 	if ((attr_version != 0 && fi->attr_version > attr_version) ||
215 	    test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
216 		spin_unlock(&fc->lock);
217 		return;
218 	}
219 
220 	old_mtime = inode->i_mtime;
221 	fuse_change_attributes_common(inode, attr, attr_valid);
222 
223 	oldsize = inode->i_size;
224 	/*
225 	 * In case of writeback_cache enabled, the cached writes beyond EOF
226 	 * extend local i_size without keeping userspace server in sync. So,
227 	 * attr->size coming from server can be stale. We cannot trust it.
228 	 */
229 	if (!is_wb || !S_ISREG(inode->i_mode))
230 		i_size_write(inode, attr->size);
231 	spin_unlock(&fc->lock);
232 
233 	if (!is_wb && S_ISREG(inode->i_mode)) {
234 		bool inval = false;
235 
236 		if (oldsize != attr->size) {
237 			truncate_pagecache(inode, attr->size);
238 			inval = true;
239 		} else if (fc->auto_inval_data) {
240 			struct timespec new_mtime = {
241 				.tv_sec = attr->mtime,
242 				.tv_nsec = attr->mtimensec,
243 			};
244 
245 			/*
246 			 * Auto inval mode also checks and invalidates if mtime
247 			 * has changed.
248 			 */
249 			if (!timespec_equal(&old_mtime, &new_mtime))
250 				inval = true;
251 		}
252 
253 		if (inval)
254 			invalidate_inode_pages2(inode->i_mapping);
255 	}
256 }
257 
258 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
259 {
260 	inode->i_mode = attr->mode & S_IFMT;
261 	inode->i_size = attr->size;
262 	inode->i_mtime.tv_sec  = attr->mtime;
263 	inode->i_mtime.tv_nsec = attr->mtimensec;
264 	inode->i_ctime.tv_sec  = attr->ctime;
265 	inode->i_ctime.tv_nsec = attr->ctimensec;
266 	if (S_ISREG(inode->i_mode)) {
267 		fuse_init_common(inode);
268 		fuse_init_file_inode(inode);
269 	} else if (S_ISDIR(inode->i_mode))
270 		fuse_init_dir(inode);
271 	else if (S_ISLNK(inode->i_mode))
272 		fuse_init_symlink(inode);
273 	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
274 		 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
275 		fuse_init_common(inode);
276 		init_special_inode(inode, inode->i_mode,
277 				   new_decode_dev(attr->rdev));
278 	} else
279 		BUG();
280 }
281 
282 int fuse_inode_eq(struct inode *inode, void *_nodeidp)
283 {
284 	u64 nodeid = *(u64 *) _nodeidp;
285 	if (get_node_id(inode) == nodeid)
286 		return 1;
287 	else
288 		return 0;
289 }
290 
291 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
292 {
293 	u64 nodeid = *(u64 *) _nodeidp;
294 	get_fuse_inode(inode)->nodeid = nodeid;
295 	return 0;
296 }
297 
298 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
299 			int generation, struct fuse_attr *attr,
300 			u64 attr_valid, u64 attr_version)
301 {
302 	struct inode *inode;
303 	struct fuse_inode *fi;
304 	struct fuse_conn *fc = get_fuse_conn_super(sb);
305 
306  retry:
307 	inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
308 	if (!inode)
309 		return NULL;
310 
311 	if ((inode->i_state & I_NEW)) {
312 		inode->i_flags |= S_NOATIME;
313 		if (!fc->writeback_cache || !S_ISREG(attr->mode))
314 			inode->i_flags |= S_NOCMTIME;
315 		inode->i_generation = generation;
316 		fuse_init_inode(inode, attr);
317 		unlock_new_inode(inode);
318 	} else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
319 		/* Inode has changed type, any I/O on the old should fail */
320 		make_bad_inode(inode);
321 		iput(inode);
322 		goto retry;
323 	}
324 
325 	fi = get_fuse_inode(inode);
326 	spin_lock(&fc->lock);
327 	fi->nlookup++;
328 	spin_unlock(&fc->lock);
329 	fuse_change_attributes(inode, attr, attr_valid, attr_version);
330 
331 	return inode;
332 }
333 
334 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
335 			     loff_t offset, loff_t len)
336 {
337 	struct inode *inode;
338 	pgoff_t pg_start;
339 	pgoff_t pg_end;
340 
341 	inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
342 	if (!inode)
343 		return -ENOENT;
344 
345 	fuse_invalidate_attr(inode);
346 	forget_all_cached_acls(inode);
347 	if (offset >= 0) {
348 		pg_start = offset >> PAGE_SHIFT;
349 		if (len <= 0)
350 			pg_end = -1;
351 		else
352 			pg_end = (offset + len - 1) >> PAGE_SHIFT;
353 		invalidate_inode_pages2_range(inode->i_mapping,
354 					      pg_start, pg_end);
355 	}
356 	iput(inode);
357 	return 0;
358 }
359 
360 void fuse_lock_inode(struct inode *inode)
361 {
362 	if (!get_fuse_conn(inode)->parallel_dirops)
363 		mutex_lock(&get_fuse_inode(inode)->mutex);
364 }
365 
366 void fuse_unlock_inode(struct inode *inode)
367 {
368 	if (!get_fuse_conn(inode)->parallel_dirops)
369 		mutex_unlock(&get_fuse_inode(inode)->mutex);
370 }
371 
372 static void fuse_umount_begin(struct super_block *sb)
373 {
374 	fuse_abort_conn(get_fuse_conn_super(sb));
375 }
376 
377 static void fuse_send_destroy(struct fuse_conn *fc)
378 {
379 	struct fuse_req *req = fc->destroy_req;
380 	if (req && fc->conn_init) {
381 		fc->destroy_req = NULL;
382 		req->in.h.opcode = FUSE_DESTROY;
383 		__set_bit(FR_FORCE, &req->flags);
384 		__clear_bit(FR_BACKGROUND, &req->flags);
385 		fuse_request_send(fc, req);
386 		fuse_put_request(fc, req);
387 	}
388 }
389 
390 static void fuse_put_super(struct super_block *sb)
391 {
392 	struct fuse_conn *fc = get_fuse_conn_super(sb);
393 
394 	fuse_send_destroy(fc);
395 
396 	fuse_abort_conn(fc);
397 	mutex_lock(&fuse_mutex);
398 	list_del(&fc->entry);
399 	fuse_ctl_remove_conn(fc);
400 	mutex_unlock(&fuse_mutex);
401 
402 	fuse_conn_put(fc);
403 }
404 
405 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
406 {
407 	stbuf->f_type    = FUSE_SUPER_MAGIC;
408 	stbuf->f_bsize   = attr->bsize;
409 	stbuf->f_frsize  = attr->frsize;
410 	stbuf->f_blocks  = attr->blocks;
411 	stbuf->f_bfree   = attr->bfree;
412 	stbuf->f_bavail  = attr->bavail;
413 	stbuf->f_files   = attr->files;
414 	stbuf->f_ffree   = attr->ffree;
415 	stbuf->f_namelen = attr->namelen;
416 	/* fsid is left zero */
417 }
418 
419 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
420 {
421 	struct super_block *sb = dentry->d_sb;
422 	struct fuse_conn *fc = get_fuse_conn_super(sb);
423 	FUSE_ARGS(args);
424 	struct fuse_statfs_out outarg;
425 	int err;
426 
427 	if (!fuse_allow_current_process(fc)) {
428 		buf->f_type = FUSE_SUPER_MAGIC;
429 		return 0;
430 	}
431 
432 	memset(&outarg, 0, sizeof(outarg));
433 	args.in.numargs = 0;
434 	args.in.h.opcode = FUSE_STATFS;
435 	args.in.h.nodeid = get_node_id(d_inode(dentry));
436 	args.out.numargs = 1;
437 	args.out.args[0].size = sizeof(outarg);
438 	args.out.args[0].value = &outarg;
439 	err = fuse_simple_request(fc, &args);
440 	if (!err)
441 		convert_fuse_statfs(buf, &outarg.st);
442 	return err;
443 }
444 
445 enum {
446 	OPT_FD,
447 	OPT_ROOTMODE,
448 	OPT_USER_ID,
449 	OPT_GROUP_ID,
450 	OPT_DEFAULT_PERMISSIONS,
451 	OPT_ALLOW_OTHER,
452 	OPT_MAX_READ,
453 	OPT_BLKSIZE,
454 	OPT_ERR
455 };
456 
457 static const match_table_t tokens = {
458 	{OPT_FD,			"fd=%u"},
459 	{OPT_ROOTMODE,			"rootmode=%o"},
460 	{OPT_USER_ID,			"user_id=%u"},
461 	{OPT_GROUP_ID,			"group_id=%u"},
462 	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
463 	{OPT_ALLOW_OTHER,		"allow_other"},
464 	{OPT_MAX_READ,			"max_read=%u"},
465 	{OPT_BLKSIZE,			"blksize=%u"},
466 	{OPT_ERR,			NULL}
467 };
468 
469 static int fuse_match_uint(substring_t *s, unsigned int *res)
470 {
471 	int err = -ENOMEM;
472 	char *buf = match_strdup(s);
473 	if (buf) {
474 		err = kstrtouint(buf, 10, res);
475 		kfree(buf);
476 	}
477 	return err;
478 }
479 
480 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
481 {
482 	char *p;
483 	memset(d, 0, sizeof(struct fuse_mount_data));
484 	d->max_read = ~0;
485 	d->blksize = FUSE_DEFAULT_BLKSIZE;
486 
487 	while ((p = strsep(&opt, ",")) != NULL) {
488 		int token;
489 		int value;
490 		unsigned uv;
491 		substring_t args[MAX_OPT_ARGS];
492 		if (!*p)
493 			continue;
494 
495 		token = match_token(p, tokens, args);
496 		switch (token) {
497 		case OPT_FD:
498 			if (match_int(&args[0], &value))
499 				return 0;
500 			d->fd = value;
501 			d->fd_present = 1;
502 			break;
503 
504 		case OPT_ROOTMODE:
505 			if (match_octal(&args[0], &value))
506 				return 0;
507 			if (!fuse_valid_type(value))
508 				return 0;
509 			d->rootmode = value;
510 			d->rootmode_present = 1;
511 			break;
512 
513 		case OPT_USER_ID:
514 			if (fuse_match_uint(&args[0], &uv))
515 				return 0;
516 			d->user_id = make_kuid(current_user_ns(), uv);
517 			if (!uid_valid(d->user_id))
518 				return 0;
519 			d->user_id_present = 1;
520 			break;
521 
522 		case OPT_GROUP_ID:
523 			if (fuse_match_uint(&args[0], &uv))
524 				return 0;
525 			d->group_id = make_kgid(current_user_ns(), uv);
526 			if (!gid_valid(d->group_id))
527 				return 0;
528 			d->group_id_present = 1;
529 			break;
530 
531 		case OPT_DEFAULT_PERMISSIONS:
532 			d->default_permissions = 1;
533 			break;
534 
535 		case OPT_ALLOW_OTHER:
536 			d->allow_other = 1;
537 			break;
538 
539 		case OPT_MAX_READ:
540 			if (match_int(&args[0], &value))
541 				return 0;
542 			d->max_read = value;
543 			break;
544 
545 		case OPT_BLKSIZE:
546 			if (!is_bdev || match_int(&args[0], &value))
547 				return 0;
548 			d->blksize = value;
549 			break;
550 
551 		default:
552 			return 0;
553 		}
554 	}
555 
556 	if (!d->fd_present || !d->rootmode_present ||
557 	    !d->user_id_present || !d->group_id_present)
558 		return 0;
559 
560 	return 1;
561 }
562 
563 static int fuse_show_options(struct seq_file *m, struct dentry *root)
564 {
565 	struct super_block *sb = root->d_sb;
566 	struct fuse_conn *fc = get_fuse_conn_super(sb);
567 
568 	seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id));
569 	seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id));
570 	if (fc->default_permissions)
571 		seq_puts(m, ",default_permissions");
572 	if (fc->allow_other)
573 		seq_puts(m, ",allow_other");
574 	if (fc->max_read != ~0)
575 		seq_printf(m, ",max_read=%u", fc->max_read);
576 	if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
577 		seq_printf(m, ",blksize=%lu", sb->s_blocksize);
578 	return 0;
579 }
580 
581 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
582 {
583 	memset(fiq, 0, sizeof(struct fuse_iqueue));
584 	init_waitqueue_head(&fiq->waitq);
585 	INIT_LIST_HEAD(&fiq->pending);
586 	INIT_LIST_HEAD(&fiq->interrupts);
587 	fiq->forget_list_tail = &fiq->forget_list_head;
588 	fiq->connected = 1;
589 }
590 
591 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
592 {
593 	memset(fpq, 0, sizeof(struct fuse_pqueue));
594 	spin_lock_init(&fpq->lock);
595 	INIT_LIST_HEAD(&fpq->processing);
596 	INIT_LIST_HEAD(&fpq->io);
597 	fpq->connected = 1;
598 }
599 
600 void fuse_conn_init(struct fuse_conn *fc)
601 {
602 	memset(fc, 0, sizeof(*fc));
603 	spin_lock_init(&fc->lock);
604 	init_rwsem(&fc->killsb);
605 	refcount_set(&fc->count, 1);
606 	atomic_set(&fc->dev_count, 1);
607 	init_waitqueue_head(&fc->blocked_waitq);
608 	init_waitqueue_head(&fc->reserved_req_waitq);
609 	fuse_iqueue_init(&fc->iq);
610 	INIT_LIST_HEAD(&fc->bg_queue);
611 	INIT_LIST_HEAD(&fc->entry);
612 	INIT_LIST_HEAD(&fc->devices);
613 	atomic_set(&fc->num_waiting, 0);
614 	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
615 	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
616 	fc->khctr = 0;
617 	fc->polled_files = RB_ROOT;
618 	fc->blocked = 0;
619 	fc->initialized = 0;
620 	fc->connected = 1;
621 	fc->attr_version = 1;
622 	get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
623 	fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
624 }
625 EXPORT_SYMBOL_GPL(fuse_conn_init);
626 
627 void fuse_conn_put(struct fuse_conn *fc)
628 {
629 	if (refcount_dec_and_test(&fc->count)) {
630 		if (fc->destroy_req)
631 			fuse_request_free(fc->destroy_req);
632 		put_pid_ns(fc->pid_ns);
633 		fc->release(fc);
634 	}
635 }
636 EXPORT_SYMBOL_GPL(fuse_conn_put);
637 
638 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
639 {
640 	refcount_inc(&fc->count);
641 	return fc;
642 }
643 EXPORT_SYMBOL_GPL(fuse_conn_get);
644 
645 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
646 {
647 	struct fuse_attr attr;
648 	memset(&attr, 0, sizeof(attr));
649 
650 	attr.mode = mode;
651 	attr.ino = FUSE_ROOT_ID;
652 	attr.nlink = 1;
653 	return fuse_iget(sb, 1, 0, &attr, 0, 0);
654 }
655 
656 struct fuse_inode_handle {
657 	u64 nodeid;
658 	u32 generation;
659 };
660 
661 static struct dentry *fuse_get_dentry(struct super_block *sb,
662 				      struct fuse_inode_handle *handle)
663 {
664 	struct fuse_conn *fc = get_fuse_conn_super(sb);
665 	struct inode *inode;
666 	struct dentry *entry;
667 	int err = -ESTALE;
668 
669 	if (handle->nodeid == 0)
670 		goto out_err;
671 
672 	inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
673 	if (!inode) {
674 		struct fuse_entry_out outarg;
675 		const struct qstr name = QSTR_INIT(".", 1);
676 
677 		if (!fc->export_support)
678 			goto out_err;
679 
680 		err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
681 				       &inode);
682 		if (err && err != -ENOENT)
683 			goto out_err;
684 		if (err || !inode) {
685 			err = -ESTALE;
686 			goto out_err;
687 		}
688 		err = -EIO;
689 		if (get_node_id(inode) != handle->nodeid)
690 			goto out_iput;
691 	}
692 	err = -ESTALE;
693 	if (inode->i_generation != handle->generation)
694 		goto out_iput;
695 
696 	entry = d_obtain_alias(inode);
697 	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
698 		fuse_invalidate_entry_cache(entry);
699 
700 	return entry;
701 
702  out_iput:
703 	iput(inode);
704  out_err:
705 	return ERR_PTR(err);
706 }
707 
708 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
709 			   struct inode *parent)
710 {
711 	int len = parent ? 6 : 3;
712 	u64 nodeid;
713 	u32 generation;
714 
715 	if (*max_len < len) {
716 		*max_len = len;
717 		return  FILEID_INVALID;
718 	}
719 
720 	nodeid = get_fuse_inode(inode)->nodeid;
721 	generation = inode->i_generation;
722 
723 	fh[0] = (u32)(nodeid >> 32);
724 	fh[1] = (u32)(nodeid & 0xffffffff);
725 	fh[2] = generation;
726 
727 	if (parent) {
728 		nodeid = get_fuse_inode(parent)->nodeid;
729 		generation = parent->i_generation;
730 
731 		fh[3] = (u32)(nodeid >> 32);
732 		fh[4] = (u32)(nodeid & 0xffffffff);
733 		fh[5] = generation;
734 	}
735 
736 	*max_len = len;
737 	return parent ? 0x82 : 0x81;
738 }
739 
740 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
741 		struct fid *fid, int fh_len, int fh_type)
742 {
743 	struct fuse_inode_handle handle;
744 
745 	if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
746 		return NULL;
747 
748 	handle.nodeid = (u64) fid->raw[0] << 32;
749 	handle.nodeid |= (u64) fid->raw[1];
750 	handle.generation = fid->raw[2];
751 	return fuse_get_dentry(sb, &handle);
752 }
753 
754 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
755 		struct fid *fid, int fh_len, int fh_type)
756 {
757 	struct fuse_inode_handle parent;
758 
759 	if (fh_type != 0x82 || fh_len < 6)
760 		return NULL;
761 
762 	parent.nodeid = (u64) fid->raw[3] << 32;
763 	parent.nodeid |= (u64) fid->raw[4];
764 	parent.generation = fid->raw[5];
765 	return fuse_get_dentry(sb, &parent);
766 }
767 
768 static struct dentry *fuse_get_parent(struct dentry *child)
769 {
770 	struct inode *child_inode = d_inode(child);
771 	struct fuse_conn *fc = get_fuse_conn(child_inode);
772 	struct inode *inode;
773 	struct dentry *parent;
774 	struct fuse_entry_out outarg;
775 	const struct qstr name = QSTR_INIT("..", 2);
776 	int err;
777 
778 	if (!fc->export_support)
779 		return ERR_PTR(-ESTALE);
780 
781 	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
782 			       &name, &outarg, &inode);
783 	if (err) {
784 		if (err == -ENOENT)
785 			return ERR_PTR(-ESTALE);
786 		return ERR_PTR(err);
787 	}
788 
789 	parent = d_obtain_alias(inode);
790 	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
791 		fuse_invalidate_entry_cache(parent);
792 
793 	return parent;
794 }
795 
796 static const struct export_operations fuse_export_operations = {
797 	.fh_to_dentry	= fuse_fh_to_dentry,
798 	.fh_to_parent	= fuse_fh_to_parent,
799 	.encode_fh	= fuse_encode_fh,
800 	.get_parent	= fuse_get_parent,
801 };
802 
803 static const struct super_operations fuse_super_operations = {
804 	.alloc_inode    = fuse_alloc_inode,
805 	.destroy_inode  = fuse_destroy_inode,
806 	.evict_inode	= fuse_evict_inode,
807 	.write_inode	= fuse_write_inode,
808 	.drop_inode	= generic_delete_inode,
809 	.remount_fs	= fuse_remount_fs,
810 	.put_super	= fuse_put_super,
811 	.umount_begin	= fuse_umount_begin,
812 	.statfs		= fuse_statfs,
813 	.show_options	= fuse_show_options,
814 };
815 
816 static void sanitize_global_limit(unsigned *limit)
817 {
818 	if (*limit == 0)
819 		*limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
820 			 sizeof(struct fuse_req);
821 
822 	if (*limit >= 1 << 16)
823 		*limit = (1 << 16) - 1;
824 }
825 
826 static int set_global_limit(const char *val, struct kernel_param *kp)
827 {
828 	int rv;
829 
830 	rv = param_set_uint(val, kp);
831 	if (rv)
832 		return rv;
833 
834 	sanitize_global_limit((unsigned *)kp->arg);
835 
836 	return 0;
837 }
838 
839 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
840 {
841 	int cap_sys_admin = capable(CAP_SYS_ADMIN);
842 
843 	if (arg->minor < 13)
844 		return;
845 
846 	sanitize_global_limit(&max_user_bgreq);
847 	sanitize_global_limit(&max_user_congthresh);
848 
849 	if (arg->max_background) {
850 		fc->max_background = arg->max_background;
851 
852 		if (!cap_sys_admin && fc->max_background > max_user_bgreq)
853 			fc->max_background = max_user_bgreq;
854 	}
855 	if (arg->congestion_threshold) {
856 		fc->congestion_threshold = arg->congestion_threshold;
857 
858 		if (!cap_sys_admin &&
859 		    fc->congestion_threshold > max_user_congthresh)
860 			fc->congestion_threshold = max_user_congthresh;
861 	}
862 }
863 
864 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
865 {
866 	struct fuse_init_out *arg = &req->misc.init_out;
867 
868 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
869 		fc->conn_error = 1;
870 	else {
871 		unsigned long ra_pages;
872 
873 		process_init_limits(fc, arg);
874 
875 		if (arg->minor >= 6) {
876 			ra_pages = arg->max_readahead / PAGE_SIZE;
877 			if (arg->flags & FUSE_ASYNC_READ)
878 				fc->async_read = 1;
879 			if (!(arg->flags & FUSE_POSIX_LOCKS))
880 				fc->no_lock = 1;
881 			if (arg->minor >= 17) {
882 				if (!(arg->flags & FUSE_FLOCK_LOCKS))
883 					fc->no_flock = 1;
884 			} else {
885 				if (!(arg->flags & FUSE_POSIX_LOCKS))
886 					fc->no_flock = 1;
887 			}
888 			if (arg->flags & FUSE_ATOMIC_O_TRUNC)
889 				fc->atomic_o_trunc = 1;
890 			if (arg->minor >= 9) {
891 				/* LOOKUP has dependency on proto version */
892 				if (arg->flags & FUSE_EXPORT_SUPPORT)
893 					fc->export_support = 1;
894 			}
895 			if (arg->flags & FUSE_BIG_WRITES)
896 				fc->big_writes = 1;
897 			if (arg->flags & FUSE_DONT_MASK)
898 				fc->dont_mask = 1;
899 			if (arg->flags & FUSE_AUTO_INVAL_DATA)
900 				fc->auto_inval_data = 1;
901 			if (arg->flags & FUSE_DO_READDIRPLUS) {
902 				fc->do_readdirplus = 1;
903 				if (arg->flags & FUSE_READDIRPLUS_AUTO)
904 					fc->readdirplus_auto = 1;
905 			}
906 			if (arg->flags & FUSE_ASYNC_DIO)
907 				fc->async_dio = 1;
908 			if (arg->flags & FUSE_WRITEBACK_CACHE)
909 				fc->writeback_cache = 1;
910 			if (arg->flags & FUSE_PARALLEL_DIROPS)
911 				fc->parallel_dirops = 1;
912 			if (arg->flags & FUSE_HANDLE_KILLPRIV)
913 				fc->handle_killpriv = 1;
914 			if (arg->time_gran && arg->time_gran <= 1000000000)
915 				fc->sb->s_time_gran = arg->time_gran;
916 			if ((arg->flags & FUSE_POSIX_ACL)) {
917 				fc->default_permissions = 1;
918 				fc->posix_acl = 1;
919 				fc->sb->s_xattr = fuse_acl_xattr_handlers;
920 			}
921 		} else {
922 			ra_pages = fc->max_read / PAGE_SIZE;
923 			fc->no_lock = 1;
924 			fc->no_flock = 1;
925 		}
926 
927 		fc->sb->s_bdi->ra_pages =
928 				min(fc->sb->s_bdi->ra_pages, ra_pages);
929 		fc->minor = arg->minor;
930 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
931 		fc->max_write = max_t(unsigned, 4096, fc->max_write);
932 		fc->conn_init = 1;
933 	}
934 	fuse_set_initialized(fc);
935 	wake_up_all(&fc->blocked_waitq);
936 }
937 
938 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
939 {
940 	struct fuse_init_in *arg = &req->misc.init_in;
941 
942 	arg->major = FUSE_KERNEL_VERSION;
943 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
944 	arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
945 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
946 		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
947 		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
948 		FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
949 		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
950 		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
951 		FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL;
952 	req->in.h.opcode = FUSE_INIT;
953 	req->in.numargs = 1;
954 	req->in.args[0].size = sizeof(*arg);
955 	req->in.args[0].value = arg;
956 	req->out.numargs = 1;
957 	/* Variable length argument used for backward compatibility
958 	   with interface version < 7.5.  Rest of init_out is zeroed
959 	   by do_get_request(), so a short reply is not a problem */
960 	req->out.argvar = 1;
961 	req->out.args[0].size = sizeof(struct fuse_init_out);
962 	req->out.args[0].value = &req->misc.init_out;
963 	req->end = process_init_reply;
964 	fuse_request_send_background(fc, req);
965 }
966 
967 static void fuse_free_conn(struct fuse_conn *fc)
968 {
969 	WARN_ON(!list_empty(&fc->devices));
970 	kfree_rcu(fc, rcu);
971 }
972 
973 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
974 {
975 	int err;
976 	char *suffix = "";
977 
978 	if (sb->s_bdev) {
979 		suffix = "-fuseblk";
980 		/*
981 		 * sb->s_bdi points to blkdev's bdi however we want to redirect
982 		 * it to our private bdi...
983 		 */
984 		bdi_put(sb->s_bdi);
985 		sb->s_bdi = &noop_backing_dev_info;
986 	}
987 	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
988 				   MINOR(fc->dev), suffix);
989 	if (err)
990 		return err;
991 
992 	sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
993 	/* fuse does it's own writeback accounting */
994 	sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
995 
996 	/*
997 	 * For a single fuse filesystem use max 1% of dirty +
998 	 * writeback threshold.
999 	 *
1000 	 * This gives about 1M of write buffer for memory maps on a
1001 	 * machine with 1G and 10% dirty_ratio, which should be more
1002 	 * than enough.
1003 	 *
1004 	 * Privileged users can raise it by writing to
1005 	 *
1006 	 *    /sys/class/bdi/<bdi>/max_ratio
1007 	 */
1008 	bdi_set_max_ratio(sb->s_bdi, 1);
1009 
1010 	return 0;
1011 }
1012 
1013 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1014 {
1015 	struct fuse_dev *fud;
1016 
1017 	fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1018 	if (fud) {
1019 		fud->fc = fuse_conn_get(fc);
1020 		fuse_pqueue_init(&fud->pq);
1021 
1022 		spin_lock(&fc->lock);
1023 		list_add_tail(&fud->entry, &fc->devices);
1024 		spin_unlock(&fc->lock);
1025 	}
1026 
1027 	return fud;
1028 }
1029 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1030 
1031 void fuse_dev_free(struct fuse_dev *fud)
1032 {
1033 	struct fuse_conn *fc = fud->fc;
1034 
1035 	if (fc) {
1036 		spin_lock(&fc->lock);
1037 		list_del(&fud->entry);
1038 		spin_unlock(&fc->lock);
1039 
1040 		fuse_conn_put(fc);
1041 	}
1042 	kfree(fud);
1043 }
1044 EXPORT_SYMBOL_GPL(fuse_dev_free);
1045 
1046 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1047 {
1048 	struct fuse_dev *fud;
1049 	struct fuse_conn *fc;
1050 	struct inode *root;
1051 	struct fuse_mount_data d;
1052 	struct file *file;
1053 	struct dentry *root_dentry;
1054 	struct fuse_req *init_req;
1055 	int err;
1056 	int is_bdev = sb->s_bdev != NULL;
1057 
1058 	err = -EINVAL;
1059 	if (sb->s_flags & MS_MANDLOCK)
1060 		goto err;
1061 
1062 	sb->s_flags &= ~(MS_NOSEC | MS_I_VERSION);
1063 
1064 	if (!parse_fuse_opt(data, &d, is_bdev))
1065 		goto err;
1066 
1067 	if (is_bdev) {
1068 #ifdef CONFIG_BLOCK
1069 		err = -EINVAL;
1070 		if (!sb_set_blocksize(sb, d.blksize))
1071 			goto err;
1072 #endif
1073 	} else {
1074 		sb->s_blocksize = PAGE_SIZE;
1075 		sb->s_blocksize_bits = PAGE_SHIFT;
1076 	}
1077 	sb->s_magic = FUSE_SUPER_MAGIC;
1078 	sb->s_op = &fuse_super_operations;
1079 	sb->s_xattr = fuse_xattr_handlers;
1080 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1081 	sb->s_time_gran = 1;
1082 	sb->s_export_op = &fuse_export_operations;
1083 
1084 	file = fget(d.fd);
1085 	err = -EINVAL;
1086 	if (!file)
1087 		goto err;
1088 
1089 	if ((file->f_op != &fuse_dev_operations) ||
1090 	    (file->f_cred->user_ns != &init_user_ns))
1091 		goto err_fput;
1092 
1093 	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1094 	err = -ENOMEM;
1095 	if (!fc)
1096 		goto err_fput;
1097 
1098 	fuse_conn_init(fc);
1099 	fc->release = fuse_free_conn;
1100 
1101 	fud = fuse_dev_alloc(fc);
1102 	if (!fud)
1103 		goto err_put_conn;
1104 
1105 	fc->dev = sb->s_dev;
1106 	fc->sb = sb;
1107 	err = fuse_bdi_init(fc, sb);
1108 	if (err)
1109 		goto err_dev_free;
1110 
1111 	/* Handle umasking inside the fuse code */
1112 	if (sb->s_flags & MS_POSIXACL)
1113 		fc->dont_mask = 1;
1114 	sb->s_flags |= MS_POSIXACL;
1115 
1116 	fc->default_permissions = d.default_permissions;
1117 	fc->allow_other = d.allow_other;
1118 	fc->user_id = d.user_id;
1119 	fc->group_id = d.group_id;
1120 	fc->max_read = max_t(unsigned, 4096, d.max_read);
1121 
1122 	/* Used by get_root_inode() */
1123 	sb->s_fs_info = fc;
1124 
1125 	err = -ENOMEM;
1126 	root = fuse_get_root_inode(sb, d.rootmode);
1127 	sb->s_d_op = &fuse_root_dentry_operations;
1128 	root_dentry = d_make_root(root);
1129 	if (!root_dentry)
1130 		goto err_dev_free;
1131 	/* Root dentry doesn't have .d_revalidate */
1132 	sb->s_d_op = &fuse_dentry_operations;
1133 
1134 	init_req = fuse_request_alloc(0);
1135 	if (!init_req)
1136 		goto err_put_root;
1137 	__set_bit(FR_BACKGROUND, &init_req->flags);
1138 
1139 	if (is_bdev) {
1140 		fc->destroy_req = fuse_request_alloc(0);
1141 		if (!fc->destroy_req)
1142 			goto err_free_init_req;
1143 	}
1144 
1145 	mutex_lock(&fuse_mutex);
1146 	err = -EINVAL;
1147 	if (file->private_data)
1148 		goto err_unlock;
1149 
1150 	err = fuse_ctl_add_conn(fc);
1151 	if (err)
1152 		goto err_unlock;
1153 
1154 	list_add_tail(&fc->entry, &fuse_conn_list);
1155 	sb->s_root = root_dentry;
1156 	file->private_data = fud;
1157 	mutex_unlock(&fuse_mutex);
1158 	/*
1159 	 * atomic_dec_and_test() in fput() provides the necessary
1160 	 * memory barrier for file->private_data to be visible on all
1161 	 * CPUs after this
1162 	 */
1163 	fput(file);
1164 
1165 	fuse_send_init(fc, init_req);
1166 
1167 	return 0;
1168 
1169  err_unlock:
1170 	mutex_unlock(&fuse_mutex);
1171  err_free_init_req:
1172 	fuse_request_free(init_req);
1173  err_put_root:
1174 	dput(root_dentry);
1175  err_dev_free:
1176 	fuse_dev_free(fud);
1177  err_put_conn:
1178 	fuse_conn_put(fc);
1179  err_fput:
1180 	fput(file);
1181  err:
1182 	return err;
1183 }
1184 
1185 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1186 		       int flags, const char *dev_name,
1187 		       void *raw_data)
1188 {
1189 	return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1190 }
1191 
1192 static void fuse_kill_sb_anon(struct super_block *sb)
1193 {
1194 	struct fuse_conn *fc = get_fuse_conn_super(sb);
1195 
1196 	if (fc) {
1197 		down_write(&fc->killsb);
1198 		fc->sb = NULL;
1199 		up_write(&fc->killsb);
1200 	}
1201 
1202 	kill_anon_super(sb);
1203 }
1204 
1205 static struct file_system_type fuse_fs_type = {
1206 	.owner		= THIS_MODULE,
1207 	.name		= "fuse",
1208 	.fs_flags	= FS_HAS_SUBTYPE,
1209 	.mount		= fuse_mount,
1210 	.kill_sb	= fuse_kill_sb_anon,
1211 };
1212 MODULE_ALIAS_FS("fuse");
1213 
1214 #ifdef CONFIG_BLOCK
1215 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1216 			   int flags, const char *dev_name,
1217 			   void *raw_data)
1218 {
1219 	return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1220 }
1221 
1222 static void fuse_kill_sb_blk(struct super_block *sb)
1223 {
1224 	struct fuse_conn *fc = get_fuse_conn_super(sb);
1225 
1226 	if (fc) {
1227 		down_write(&fc->killsb);
1228 		fc->sb = NULL;
1229 		up_write(&fc->killsb);
1230 	}
1231 
1232 	kill_block_super(sb);
1233 }
1234 
1235 static struct file_system_type fuseblk_fs_type = {
1236 	.owner		= THIS_MODULE,
1237 	.name		= "fuseblk",
1238 	.mount		= fuse_mount_blk,
1239 	.kill_sb	= fuse_kill_sb_blk,
1240 	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1241 };
1242 MODULE_ALIAS_FS("fuseblk");
1243 
1244 static inline int register_fuseblk(void)
1245 {
1246 	return register_filesystem(&fuseblk_fs_type);
1247 }
1248 
1249 static inline void unregister_fuseblk(void)
1250 {
1251 	unregister_filesystem(&fuseblk_fs_type);
1252 }
1253 #else
1254 static inline int register_fuseblk(void)
1255 {
1256 	return 0;
1257 }
1258 
1259 static inline void unregister_fuseblk(void)
1260 {
1261 }
1262 #endif
1263 
1264 static void fuse_inode_init_once(void *foo)
1265 {
1266 	struct inode *inode = foo;
1267 
1268 	inode_init_once(inode);
1269 }
1270 
1271 static int __init fuse_fs_init(void)
1272 {
1273 	int err;
1274 
1275 	fuse_inode_cachep = kmem_cache_create("fuse_inode",
1276 					      sizeof(struct fuse_inode), 0,
1277 					      SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
1278 					      fuse_inode_init_once);
1279 	err = -ENOMEM;
1280 	if (!fuse_inode_cachep)
1281 		goto out;
1282 
1283 	err = register_fuseblk();
1284 	if (err)
1285 		goto out2;
1286 
1287 	err = register_filesystem(&fuse_fs_type);
1288 	if (err)
1289 		goto out3;
1290 
1291 	return 0;
1292 
1293  out3:
1294 	unregister_fuseblk();
1295  out2:
1296 	kmem_cache_destroy(fuse_inode_cachep);
1297  out:
1298 	return err;
1299 }
1300 
1301 static void fuse_fs_cleanup(void)
1302 {
1303 	unregister_filesystem(&fuse_fs_type);
1304 	unregister_fuseblk();
1305 
1306 	/*
1307 	 * Make sure all delayed rcu free inodes are flushed before we
1308 	 * destroy cache.
1309 	 */
1310 	rcu_barrier();
1311 	kmem_cache_destroy(fuse_inode_cachep);
1312 }
1313 
1314 static struct kobject *fuse_kobj;
1315 
1316 static int fuse_sysfs_init(void)
1317 {
1318 	int err;
1319 
1320 	fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1321 	if (!fuse_kobj) {
1322 		err = -ENOMEM;
1323 		goto out_err;
1324 	}
1325 
1326 	err = sysfs_create_mount_point(fuse_kobj, "connections");
1327 	if (err)
1328 		goto out_fuse_unregister;
1329 
1330 	return 0;
1331 
1332  out_fuse_unregister:
1333 	kobject_put(fuse_kobj);
1334  out_err:
1335 	return err;
1336 }
1337 
1338 static void fuse_sysfs_cleanup(void)
1339 {
1340 	sysfs_remove_mount_point(fuse_kobj, "connections");
1341 	kobject_put(fuse_kobj);
1342 }
1343 
1344 static int __init fuse_init(void)
1345 {
1346 	int res;
1347 
1348 	printk(KERN_INFO "fuse init (API version %i.%i)\n",
1349 	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1350 
1351 	INIT_LIST_HEAD(&fuse_conn_list);
1352 	res = fuse_fs_init();
1353 	if (res)
1354 		goto err;
1355 
1356 	res = fuse_dev_init();
1357 	if (res)
1358 		goto err_fs_cleanup;
1359 
1360 	res = fuse_sysfs_init();
1361 	if (res)
1362 		goto err_dev_cleanup;
1363 
1364 	res = fuse_ctl_init();
1365 	if (res)
1366 		goto err_sysfs_cleanup;
1367 
1368 	sanitize_global_limit(&max_user_bgreq);
1369 	sanitize_global_limit(&max_user_congthresh);
1370 
1371 	return 0;
1372 
1373  err_sysfs_cleanup:
1374 	fuse_sysfs_cleanup();
1375  err_dev_cleanup:
1376 	fuse_dev_cleanup();
1377  err_fs_cleanup:
1378 	fuse_fs_cleanup();
1379  err:
1380 	return res;
1381 }
1382 
1383 static void __exit fuse_exit(void)
1384 {
1385 	printk(KERN_DEBUG "fuse exit\n");
1386 
1387 	fuse_ctl_cleanup();
1388 	fuse_sysfs_cleanup();
1389 	fuse_fs_cleanup();
1390 	fuse_dev_cleanup();
1391 }
1392 
1393 module_init(fuse_init);
1394 module_exit(fuse_exit);
1395