xref: /openbmc/linux/fs/fuse/inode.c (revision f220d3eb)
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, const 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 & SB_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 & SB_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(fc->user_ns, attr->uid);
175 	inode->i_gid     = make_kgid(fc->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 timespec64 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 timespec64 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 (!timespec64_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 bool fuse_lock_inode(struct inode *inode)
361 {
362 	bool locked = false;
363 
364 	if (!get_fuse_conn(inode)->parallel_dirops) {
365 		mutex_lock(&get_fuse_inode(inode)->mutex);
366 		locked = true;
367 	}
368 
369 	return locked;
370 }
371 
372 void fuse_unlock_inode(struct inode *inode, bool locked)
373 {
374 	if (locked)
375 		mutex_unlock(&get_fuse_inode(inode)->mutex);
376 }
377 
378 static void fuse_umount_begin(struct super_block *sb)
379 {
380 	fuse_abort_conn(get_fuse_conn_super(sb), false);
381 }
382 
383 static void fuse_send_destroy(struct fuse_conn *fc)
384 {
385 	struct fuse_req *req = fc->destroy_req;
386 	if (req && fc->conn_init) {
387 		fc->destroy_req = NULL;
388 		req->in.h.opcode = FUSE_DESTROY;
389 		__set_bit(FR_FORCE, &req->flags);
390 		__clear_bit(FR_BACKGROUND, &req->flags);
391 		fuse_request_send(fc, req);
392 		fuse_put_request(fc, req);
393 	}
394 }
395 
396 static void fuse_put_super(struct super_block *sb)
397 {
398 	struct fuse_conn *fc = get_fuse_conn_super(sb);
399 
400 	mutex_lock(&fuse_mutex);
401 	list_del(&fc->entry);
402 	fuse_ctl_remove_conn(fc);
403 	mutex_unlock(&fuse_mutex);
404 
405 	fuse_conn_put(fc);
406 }
407 
408 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
409 {
410 	stbuf->f_type    = FUSE_SUPER_MAGIC;
411 	stbuf->f_bsize   = attr->bsize;
412 	stbuf->f_frsize  = attr->frsize;
413 	stbuf->f_blocks  = attr->blocks;
414 	stbuf->f_bfree   = attr->bfree;
415 	stbuf->f_bavail  = attr->bavail;
416 	stbuf->f_files   = attr->files;
417 	stbuf->f_ffree   = attr->ffree;
418 	stbuf->f_namelen = attr->namelen;
419 	/* fsid is left zero */
420 }
421 
422 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
423 {
424 	struct super_block *sb = dentry->d_sb;
425 	struct fuse_conn *fc = get_fuse_conn_super(sb);
426 	FUSE_ARGS(args);
427 	struct fuse_statfs_out outarg;
428 	int err;
429 
430 	if (!fuse_allow_current_process(fc)) {
431 		buf->f_type = FUSE_SUPER_MAGIC;
432 		return 0;
433 	}
434 
435 	memset(&outarg, 0, sizeof(outarg));
436 	args.in.numargs = 0;
437 	args.in.h.opcode = FUSE_STATFS;
438 	args.in.h.nodeid = get_node_id(d_inode(dentry));
439 	args.out.numargs = 1;
440 	args.out.args[0].size = sizeof(outarg);
441 	args.out.args[0].value = &outarg;
442 	err = fuse_simple_request(fc, &args);
443 	if (!err)
444 		convert_fuse_statfs(buf, &outarg.st);
445 	return err;
446 }
447 
448 enum {
449 	OPT_FD,
450 	OPT_ROOTMODE,
451 	OPT_USER_ID,
452 	OPT_GROUP_ID,
453 	OPT_DEFAULT_PERMISSIONS,
454 	OPT_ALLOW_OTHER,
455 	OPT_MAX_READ,
456 	OPT_BLKSIZE,
457 	OPT_ERR
458 };
459 
460 static const match_table_t tokens = {
461 	{OPT_FD,			"fd=%u"},
462 	{OPT_ROOTMODE,			"rootmode=%o"},
463 	{OPT_USER_ID,			"user_id=%u"},
464 	{OPT_GROUP_ID,			"group_id=%u"},
465 	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},
466 	{OPT_ALLOW_OTHER,		"allow_other"},
467 	{OPT_MAX_READ,			"max_read=%u"},
468 	{OPT_BLKSIZE,			"blksize=%u"},
469 	{OPT_ERR,			NULL}
470 };
471 
472 static int fuse_match_uint(substring_t *s, unsigned int *res)
473 {
474 	int err = -ENOMEM;
475 	char *buf = match_strdup(s);
476 	if (buf) {
477 		err = kstrtouint(buf, 10, res);
478 		kfree(buf);
479 	}
480 	return err;
481 }
482 
483 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev,
484 			  struct user_namespace *user_ns)
485 {
486 	char *p;
487 	memset(d, 0, sizeof(struct fuse_mount_data));
488 	d->max_read = ~0;
489 	d->blksize = FUSE_DEFAULT_BLKSIZE;
490 
491 	while ((p = strsep(&opt, ",")) != NULL) {
492 		int token;
493 		int value;
494 		unsigned uv;
495 		substring_t args[MAX_OPT_ARGS];
496 		if (!*p)
497 			continue;
498 
499 		token = match_token(p, tokens, args);
500 		switch (token) {
501 		case OPT_FD:
502 			if (match_int(&args[0], &value))
503 				return 0;
504 			d->fd = value;
505 			d->fd_present = 1;
506 			break;
507 
508 		case OPT_ROOTMODE:
509 			if (match_octal(&args[0], &value))
510 				return 0;
511 			if (!fuse_valid_type(value))
512 				return 0;
513 			d->rootmode = value;
514 			d->rootmode_present = 1;
515 			break;
516 
517 		case OPT_USER_ID:
518 			if (fuse_match_uint(&args[0], &uv))
519 				return 0;
520 			d->user_id = make_kuid(user_ns, uv);
521 			if (!uid_valid(d->user_id))
522 				return 0;
523 			d->user_id_present = 1;
524 			break;
525 
526 		case OPT_GROUP_ID:
527 			if (fuse_match_uint(&args[0], &uv))
528 				return 0;
529 			d->group_id = make_kgid(user_ns, uv);
530 			if (!gid_valid(d->group_id))
531 				return 0;
532 			d->group_id_present = 1;
533 			break;
534 
535 		case OPT_DEFAULT_PERMISSIONS:
536 			d->default_permissions = 1;
537 			break;
538 
539 		case OPT_ALLOW_OTHER:
540 			d->allow_other = 1;
541 			break;
542 
543 		case OPT_MAX_READ:
544 			if (match_int(&args[0], &value))
545 				return 0;
546 			d->max_read = value;
547 			break;
548 
549 		case OPT_BLKSIZE:
550 			if (!is_bdev || match_int(&args[0], &value))
551 				return 0;
552 			d->blksize = value;
553 			break;
554 
555 		default:
556 			return 0;
557 		}
558 	}
559 
560 	if (!d->fd_present || !d->rootmode_present ||
561 	    !d->user_id_present || !d->group_id_present)
562 		return 0;
563 
564 	return 1;
565 }
566 
567 static int fuse_show_options(struct seq_file *m, struct dentry *root)
568 {
569 	struct super_block *sb = root->d_sb;
570 	struct fuse_conn *fc = get_fuse_conn_super(sb);
571 
572 	seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id));
573 	seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id));
574 	if (fc->default_permissions)
575 		seq_puts(m, ",default_permissions");
576 	if (fc->allow_other)
577 		seq_puts(m, ",allow_other");
578 	if (fc->max_read != ~0)
579 		seq_printf(m, ",max_read=%u", fc->max_read);
580 	if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
581 		seq_printf(m, ",blksize=%lu", sb->s_blocksize);
582 	return 0;
583 }
584 
585 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
586 {
587 	memset(fiq, 0, sizeof(struct fuse_iqueue));
588 	init_waitqueue_head(&fiq->waitq);
589 	INIT_LIST_HEAD(&fiq->pending);
590 	INIT_LIST_HEAD(&fiq->interrupts);
591 	fiq->forget_list_tail = &fiq->forget_list_head;
592 	fiq->connected = 1;
593 }
594 
595 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
596 {
597 	memset(fpq, 0, sizeof(struct fuse_pqueue));
598 	spin_lock_init(&fpq->lock);
599 	INIT_LIST_HEAD(&fpq->processing);
600 	INIT_LIST_HEAD(&fpq->io);
601 	fpq->connected = 1;
602 }
603 
604 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns)
605 {
606 	memset(fc, 0, sizeof(*fc));
607 	spin_lock_init(&fc->lock);
608 	init_rwsem(&fc->killsb);
609 	refcount_set(&fc->count, 1);
610 	atomic_set(&fc->dev_count, 1);
611 	init_waitqueue_head(&fc->blocked_waitq);
612 	init_waitqueue_head(&fc->reserved_req_waitq);
613 	fuse_iqueue_init(&fc->iq);
614 	INIT_LIST_HEAD(&fc->bg_queue);
615 	INIT_LIST_HEAD(&fc->entry);
616 	INIT_LIST_HEAD(&fc->devices);
617 	atomic_set(&fc->num_waiting, 0);
618 	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
619 	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
620 	fc->khctr = 0;
621 	fc->polled_files = RB_ROOT;
622 	fc->blocked = 0;
623 	fc->initialized = 0;
624 	fc->connected = 1;
625 	fc->attr_version = 1;
626 	get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
627 	fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
628 	fc->user_ns = get_user_ns(user_ns);
629 }
630 EXPORT_SYMBOL_GPL(fuse_conn_init);
631 
632 void fuse_conn_put(struct fuse_conn *fc)
633 {
634 	if (refcount_dec_and_test(&fc->count)) {
635 		if (fc->destroy_req)
636 			fuse_request_free(fc->destroy_req);
637 		put_pid_ns(fc->pid_ns);
638 		put_user_ns(fc->user_ns);
639 		fc->release(fc);
640 	}
641 }
642 EXPORT_SYMBOL_GPL(fuse_conn_put);
643 
644 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
645 {
646 	refcount_inc(&fc->count);
647 	return fc;
648 }
649 EXPORT_SYMBOL_GPL(fuse_conn_get);
650 
651 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
652 {
653 	struct fuse_attr attr;
654 	memset(&attr, 0, sizeof(attr));
655 
656 	attr.mode = mode;
657 	attr.ino = FUSE_ROOT_ID;
658 	attr.nlink = 1;
659 	return fuse_iget(sb, 1, 0, &attr, 0, 0);
660 }
661 
662 struct fuse_inode_handle {
663 	u64 nodeid;
664 	u32 generation;
665 };
666 
667 static struct dentry *fuse_get_dentry(struct super_block *sb,
668 				      struct fuse_inode_handle *handle)
669 {
670 	struct fuse_conn *fc = get_fuse_conn_super(sb);
671 	struct inode *inode;
672 	struct dentry *entry;
673 	int err = -ESTALE;
674 
675 	if (handle->nodeid == 0)
676 		goto out_err;
677 
678 	inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
679 	if (!inode) {
680 		struct fuse_entry_out outarg;
681 		const struct qstr name = QSTR_INIT(".", 1);
682 
683 		if (!fc->export_support)
684 			goto out_err;
685 
686 		err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
687 				       &inode);
688 		if (err && err != -ENOENT)
689 			goto out_err;
690 		if (err || !inode) {
691 			err = -ESTALE;
692 			goto out_err;
693 		}
694 		err = -EIO;
695 		if (get_node_id(inode) != handle->nodeid)
696 			goto out_iput;
697 	}
698 	err = -ESTALE;
699 	if (inode->i_generation != handle->generation)
700 		goto out_iput;
701 
702 	entry = d_obtain_alias(inode);
703 	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
704 		fuse_invalidate_entry_cache(entry);
705 
706 	return entry;
707 
708  out_iput:
709 	iput(inode);
710  out_err:
711 	return ERR_PTR(err);
712 }
713 
714 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
715 			   struct inode *parent)
716 {
717 	int len = parent ? 6 : 3;
718 	u64 nodeid;
719 	u32 generation;
720 
721 	if (*max_len < len) {
722 		*max_len = len;
723 		return  FILEID_INVALID;
724 	}
725 
726 	nodeid = get_fuse_inode(inode)->nodeid;
727 	generation = inode->i_generation;
728 
729 	fh[0] = (u32)(nodeid >> 32);
730 	fh[1] = (u32)(nodeid & 0xffffffff);
731 	fh[2] = generation;
732 
733 	if (parent) {
734 		nodeid = get_fuse_inode(parent)->nodeid;
735 		generation = parent->i_generation;
736 
737 		fh[3] = (u32)(nodeid >> 32);
738 		fh[4] = (u32)(nodeid & 0xffffffff);
739 		fh[5] = generation;
740 	}
741 
742 	*max_len = len;
743 	return parent ? 0x82 : 0x81;
744 }
745 
746 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
747 		struct fid *fid, int fh_len, int fh_type)
748 {
749 	struct fuse_inode_handle handle;
750 
751 	if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
752 		return NULL;
753 
754 	handle.nodeid = (u64) fid->raw[0] << 32;
755 	handle.nodeid |= (u64) fid->raw[1];
756 	handle.generation = fid->raw[2];
757 	return fuse_get_dentry(sb, &handle);
758 }
759 
760 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
761 		struct fid *fid, int fh_len, int fh_type)
762 {
763 	struct fuse_inode_handle parent;
764 
765 	if (fh_type != 0x82 || fh_len < 6)
766 		return NULL;
767 
768 	parent.nodeid = (u64) fid->raw[3] << 32;
769 	parent.nodeid |= (u64) fid->raw[4];
770 	parent.generation = fid->raw[5];
771 	return fuse_get_dentry(sb, &parent);
772 }
773 
774 static struct dentry *fuse_get_parent(struct dentry *child)
775 {
776 	struct inode *child_inode = d_inode(child);
777 	struct fuse_conn *fc = get_fuse_conn(child_inode);
778 	struct inode *inode;
779 	struct dentry *parent;
780 	struct fuse_entry_out outarg;
781 	const struct qstr name = QSTR_INIT("..", 2);
782 	int err;
783 
784 	if (!fc->export_support)
785 		return ERR_PTR(-ESTALE);
786 
787 	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
788 			       &name, &outarg, &inode);
789 	if (err) {
790 		if (err == -ENOENT)
791 			return ERR_PTR(-ESTALE);
792 		return ERR_PTR(err);
793 	}
794 
795 	parent = d_obtain_alias(inode);
796 	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
797 		fuse_invalidate_entry_cache(parent);
798 
799 	return parent;
800 }
801 
802 static const struct export_operations fuse_export_operations = {
803 	.fh_to_dentry	= fuse_fh_to_dentry,
804 	.fh_to_parent	= fuse_fh_to_parent,
805 	.encode_fh	= fuse_encode_fh,
806 	.get_parent	= fuse_get_parent,
807 };
808 
809 static const struct super_operations fuse_super_operations = {
810 	.alloc_inode    = fuse_alloc_inode,
811 	.destroy_inode  = fuse_destroy_inode,
812 	.evict_inode	= fuse_evict_inode,
813 	.write_inode	= fuse_write_inode,
814 	.drop_inode	= generic_delete_inode,
815 	.remount_fs	= fuse_remount_fs,
816 	.put_super	= fuse_put_super,
817 	.umount_begin	= fuse_umount_begin,
818 	.statfs		= fuse_statfs,
819 	.show_options	= fuse_show_options,
820 };
821 
822 static void sanitize_global_limit(unsigned *limit)
823 {
824 	if (*limit == 0)
825 		*limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
826 			 sizeof(struct fuse_req);
827 
828 	if (*limit >= 1 << 16)
829 		*limit = (1 << 16) - 1;
830 }
831 
832 static int set_global_limit(const char *val, const struct kernel_param *kp)
833 {
834 	int rv;
835 
836 	rv = param_set_uint(val, kp);
837 	if (rv)
838 		return rv;
839 
840 	sanitize_global_limit((unsigned *)kp->arg);
841 
842 	return 0;
843 }
844 
845 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
846 {
847 	int cap_sys_admin = capable(CAP_SYS_ADMIN);
848 
849 	if (arg->minor < 13)
850 		return;
851 
852 	sanitize_global_limit(&max_user_bgreq);
853 	sanitize_global_limit(&max_user_congthresh);
854 
855 	if (arg->max_background) {
856 		fc->max_background = arg->max_background;
857 
858 		if (!cap_sys_admin && fc->max_background > max_user_bgreq)
859 			fc->max_background = max_user_bgreq;
860 	}
861 	if (arg->congestion_threshold) {
862 		fc->congestion_threshold = arg->congestion_threshold;
863 
864 		if (!cap_sys_admin &&
865 		    fc->congestion_threshold > max_user_congthresh)
866 			fc->congestion_threshold = max_user_congthresh;
867 	}
868 }
869 
870 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
871 {
872 	struct fuse_init_out *arg = &req->misc.init_out;
873 
874 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
875 		fc->conn_error = 1;
876 	else {
877 		unsigned long ra_pages;
878 
879 		process_init_limits(fc, arg);
880 
881 		if (arg->minor >= 6) {
882 			ra_pages = arg->max_readahead / PAGE_SIZE;
883 			if (arg->flags & FUSE_ASYNC_READ)
884 				fc->async_read = 1;
885 			if (!(arg->flags & FUSE_POSIX_LOCKS))
886 				fc->no_lock = 1;
887 			if (arg->minor >= 17) {
888 				if (!(arg->flags & FUSE_FLOCK_LOCKS))
889 					fc->no_flock = 1;
890 			} else {
891 				if (!(arg->flags & FUSE_POSIX_LOCKS))
892 					fc->no_flock = 1;
893 			}
894 			if (arg->flags & FUSE_ATOMIC_O_TRUNC)
895 				fc->atomic_o_trunc = 1;
896 			if (arg->minor >= 9) {
897 				/* LOOKUP has dependency on proto version */
898 				if (arg->flags & FUSE_EXPORT_SUPPORT)
899 					fc->export_support = 1;
900 			}
901 			if (arg->flags & FUSE_BIG_WRITES)
902 				fc->big_writes = 1;
903 			if (arg->flags & FUSE_DONT_MASK)
904 				fc->dont_mask = 1;
905 			if (arg->flags & FUSE_AUTO_INVAL_DATA)
906 				fc->auto_inval_data = 1;
907 			if (arg->flags & FUSE_DO_READDIRPLUS) {
908 				fc->do_readdirplus = 1;
909 				if (arg->flags & FUSE_READDIRPLUS_AUTO)
910 					fc->readdirplus_auto = 1;
911 			}
912 			if (arg->flags & FUSE_ASYNC_DIO)
913 				fc->async_dio = 1;
914 			if (arg->flags & FUSE_WRITEBACK_CACHE)
915 				fc->writeback_cache = 1;
916 			if (arg->flags & FUSE_PARALLEL_DIROPS)
917 				fc->parallel_dirops = 1;
918 			if (arg->flags & FUSE_HANDLE_KILLPRIV)
919 				fc->handle_killpriv = 1;
920 			if (arg->time_gran && arg->time_gran <= 1000000000)
921 				fc->sb->s_time_gran = arg->time_gran;
922 			if ((arg->flags & FUSE_POSIX_ACL)) {
923 				fc->default_permissions = 1;
924 				fc->posix_acl = 1;
925 				fc->sb->s_xattr = fuse_acl_xattr_handlers;
926 			}
927 			if (arg->flags & FUSE_ABORT_ERROR)
928 				fc->abort_err = 1;
929 		} else {
930 			ra_pages = fc->max_read / PAGE_SIZE;
931 			fc->no_lock = 1;
932 			fc->no_flock = 1;
933 		}
934 
935 		fc->sb->s_bdi->ra_pages =
936 				min(fc->sb->s_bdi->ra_pages, ra_pages);
937 		fc->minor = arg->minor;
938 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
939 		fc->max_write = max_t(unsigned, 4096, fc->max_write);
940 		fc->conn_init = 1;
941 	}
942 	fuse_set_initialized(fc);
943 	wake_up_all(&fc->blocked_waitq);
944 }
945 
946 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
947 {
948 	struct fuse_init_in *arg = &req->misc.init_in;
949 
950 	arg->major = FUSE_KERNEL_VERSION;
951 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
952 	arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
953 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
954 		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
955 		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
956 		FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
957 		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
958 		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
959 		FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
960 		FUSE_ABORT_ERROR;
961 	req->in.h.opcode = FUSE_INIT;
962 	req->in.numargs = 1;
963 	req->in.args[0].size = sizeof(*arg);
964 	req->in.args[0].value = arg;
965 	req->out.numargs = 1;
966 	/* Variable length argument used for backward compatibility
967 	   with interface version < 7.5.  Rest of init_out is zeroed
968 	   by do_get_request(), so a short reply is not a problem */
969 	req->out.argvar = 1;
970 	req->out.args[0].size = sizeof(struct fuse_init_out);
971 	req->out.args[0].value = &req->misc.init_out;
972 	req->end = process_init_reply;
973 	fuse_request_send_background(fc, req);
974 }
975 
976 static void fuse_free_conn(struct fuse_conn *fc)
977 {
978 	WARN_ON(!list_empty(&fc->devices));
979 	kfree_rcu(fc, rcu);
980 }
981 
982 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
983 {
984 	int err;
985 	char *suffix = "";
986 
987 	if (sb->s_bdev) {
988 		suffix = "-fuseblk";
989 		/*
990 		 * sb->s_bdi points to blkdev's bdi however we want to redirect
991 		 * it to our private bdi...
992 		 */
993 		bdi_put(sb->s_bdi);
994 		sb->s_bdi = &noop_backing_dev_info;
995 	}
996 	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
997 				   MINOR(fc->dev), suffix);
998 	if (err)
999 		return err;
1000 
1001 	sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
1002 	/* fuse does it's own writeback accounting */
1003 	sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
1004 
1005 	/*
1006 	 * For a single fuse filesystem use max 1% of dirty +
1007 	 * writeback threshold.
1008 	 *
1009 	 * This gives about 1M of write buffer for memory maps on a
1010 	 * machine with 1G and 10% dirty_ratio, which should be more
1011 	 * than enough.
1012 	 *
1013 	 * Privileged users can raise it by writing to
1014 	 *
1015 	 *    /sys/class/bdi/<bdi>/max_ratio
1016 	 */
1017 	bdi_set_max_ratio(sb->s_bdi, 1);
1018 
1019 	return 0;
1020 }
1021 
1022 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1023 {
1024 	struct fuse_dev *fud;
1025 
1026 	fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1027 	if (fud) {
1028 		fud->fc = fuse_conn_get(fc);
1029 		fuse_pqueue_init(&fud->pq);
1030 
1031 		spin_lock(&fc->lock);
1032 		list_add_tail(&fud->entry, &fc->devices);
1033 		spin_unlock(&fc->lock);
1034 	}
1035 
1036 	return fud;
1037 }
1038 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1039 
1040 void fuse_dev_free(struct fuse_dev *fud)
1041 {
1042 	struct fuse_conn *fc = fud->fc;
1043 
1044 	if (fc) {
1045 		spin_lock(&fc->lock);
1046 		list_del(&fud->entry);
1047 		spin_unlock(&fc->lock);
1048 
1049 		fuse_conn_put(fc);
1050 	}
1051 	kfree(fud);
1052 }
1053 EXPORT_SYMBOL_GPL(fuse_dev_free);
1054 
1055 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1056 {
1057 	struct fuse_dev *fud;
1058 	struct fuse_conn *fc;
1059 	struct inode *root;
1060 	struct fuse_mount_data d;
1061 	struct file *file;
1062 	struct dentry *root_dentry;
1063 	struct fuse_req *init_req;
1064 	int err;
1065 	int is_bdev = sb->s_bdev != NULL;
1066 
1067 	err = -EINVAL;
1068 	if (sb->s_flags & SB_MANDLOCK)
1069 		goto err;
1070 
1071 	sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1072 
1073 	if (!parse_fuse_opt(data, &d, is_bdev, sb->s_user_ns))
1074 		goto err;
1075 
1076 	if (is_bdev) {
1077 #ifdef CONFIG_BLOCK
1078 		err = -EINVAL;
1079 		if (!sb_set_blocksize(sb, d.blksize))
1080 			goto err;
1081 #endif
1082 	} else {
1083 		sb->s_blocksize = PAGE_SIZE;
1084 		sb->s_blocksize_bits = PAGE_SHIFT;
1085 	}
1086 	sb->s_magic = FUSE_SUPER_MAGIC;
1087 	sb->s_op = &fuse_super_operations;
1088 	sb->s_xattr = fuse_xattr_handlers;
1089 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1090 	sb->s_time_gran = 1;
1091 	sb->s_export_op = &fuse_export_operations;
1092 	sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1093 	if (sb->s_user_ns != &init_user_ns)
1094 		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1095 
1096 	file = fget(d.fd);
1097 	err = -EINVAL;
1098 	if (!file)
1099 		goto err;
1100 
1101 	/*
1102 	 * Require mount to happen from the same user namespace which
1103 	 * opened /dev/fuse to prevent potential attacks.
1104 	 */
1105 	if (file->f_op != &fuse_dev_operations ||
1106 	    file->f_cred->user_ns != sb->s_user_ns)
1107 		goto err_fput;
1108 
1109 	/*
1110 	 * If we are not in the initial user namespace posix
1111 	 * acls must be translated.
1112 	 */
1113 	if (sb->s_user_ns != &init_user_ns)
1114 		sb->s_xattr = fuse_no_acl_xattr_handlers;
1115 
1116 	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1117 	err = -ENOMEM;
1118 	if (!fc)
1119 		goto err_fput;
1120 
1121 	fuse_conn_init(fc, sb->s_user_ns);
1122 	fc->release = fuse_free_conn;
1123 
1124 	fud = fuse_dev_alloc(fc);
1125 	if (!fud)
1126 		goto err_put_conn;
1127 
1128 	fc->dev = sb->s_dev;
1129 	fc->sb = sb;
1130 	err = fuse_bdi_init(fc, sb);
1131 	if (err)
1132 		goto err_dev_free;
1133 
1134 	/* Handle umasking inside the fuse code */
1135 	if (sb->s_flags & SB_POSIXACL)
1136 		fc->dont_mask = 1;
1137 	sb->s_flags |= SB_POSIXACL;
1138 
1139 	fc->default_permissions = d.default_permissions;
1140 	fc->allow_other = d.allow_other;
1141 	fc->user_id = d.user_id;
1142 	fc->group_id = d.group_id;
1143 	fc->max_read = max_t(unsigned, 4096, d.max_read);
1144 
1145 	/* Used by get_root_inode() */
1146 	sb->s_fs_info = fc;
1147 
1148 	err = -ENOMEM;
1149 	root = fuse_get_root_inode(sb, d.rootmode);
1150 	sb->s_d_op = &fuse_root_dentry_operations;
1151 	root_dentry = d_make_root(root);
1152 	if (!root_dentry)
1153 		goto err_dev_free;
1154 	/* Root dentry doesn't have .d_revalidate */
1155 	sb->s_d_op = &fuse_dentry_operations;
1156 
1157 	init_req = fuse_request_alloc(0);
1158 	if (!init_req)
1159 		goto err_put_root;
1160 	__set_bit(FR_BACKGROUND, &init_req->flags);
1161 
1162 	if (is_bdev) {
1163 		fc->destroy_req = fuse_request_alloc(0);
1164 		if (!fc->destroy_req)
1165 			goto err_free_init_req;
1166 	}
1167 
1168 	mutex_lock(&fuse_mutex);
1169 	err = -EINVAL;
1170 	if (file->private_data)
1171 		goto err_unlock;
1172 
1173 	err = fuse_ctl_add_conn(fc);
1174 	if (err)
1175 		goto err_unlock;
1176 
1177 	list_add_tail(&fc->entry, &fuse_conn_list);
1178 	sb->s_root = root_dentry;
1179 	file->private_data = fud;
1180 	mutex_unlock(&fuse_mutex);
1181 	/*
1182 	 * atomic_dec_and_test() in fput() provides the necessary
1183 	 * memory barrier for file->private_data to be visible on all
1184 	 * CPUs after this
1185 	 */
1186 	fput(file);
1187 
1188 	fuse_send_init(fc, init_req);
1189 
1190 	return 0;
1191 
1192  err_unlock:
1193 	mutex_unlock(&fuse_mutex);
1194  err_free_init_req:
1195 	fuse_request_free(init_req);
1196  err_put_root:
1197 	dput(root_dentry);
1198  err_dev_free:
1199 	fuse_dev_free(fud);
1200  err_put_conn:
1201 	fuse_conn_put(fc);
1202 	sb->s_fs_info = NULL;
1203  err_fput:
1204 	fput(file);
1205  err:
1206 	return err;
1207 }
1208 
1209 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1210 		       int flags, const char *dev_name,
1211 		       void *raw_data)
1212 {
1213 	return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1214 }
1215 
1216 static void fuse_sb_destroy(struct super_block *sb)
1217 {
1218 	struct fuse_conn *fc = get_fuse_conn_super(sb);
1219 
1220 	if (fc) {
1221 		fuse_send_destroy(fc);
1222 
1223 		fuse_abort_conn(fc, false);
1224 		fuse_wait_aborted(fc);
1225 
1226 		down_write(&fc->killsb);
1227 		fc->sb = NULL;
1228 		up_write(&fc->killsb);
1229 	}
1230 }
1231 
1232 static void fuse_kill_sb_anon(struct super_block *sb)
1233 {
1234 	fuse_sb_destroy(sb);
1235 	kill_anon_super(sb);
1236 }
1237 
1238 static struct file_system_type fuse_fs_type = {
1239 	.owner		= THIS_MODULE,
1240 	.name		= "fuse",
1241 	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1242 	.mount		= fuse_mount,
1243 	.kill_sb	= fuse_kill_sb_anon,
1244 };
1245 MODULE_ALIAS_FS("fuse");
1246 
1247 #ifdef CONFIG_BLOCK
1248 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1249 			   int flags, const char *dev_name,
1250 			   void *raw_data)
1251 {
1252 	return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1253 }
1254 
1255 static void fuse_kill_sb_blk(struct super_block *sb)
1256 {
1257 	fuse_sb_destroy(sb);
1258 	kill_block_super(sb);
1259 }
1260 
1261 static struct file_system_type fuseblk_fs_type = {
1262 	.owner		= THIS_MODULE,
1263 	.name		= "fuseblk",
1264 	.mount		= fuse_mount_blk,
1265 	.kill_sb	= fuse_kill_sb_blk,
1266 	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1267 };
1268 MODULE_ALIAS_FS("fuseblk");
1269 
1270 static inline int register_fuseblk(void)
1271 {
1272 	return register_filesystem(&fuseblk_fs_type);
1273 }
1274 
1275 static inline void unregister_fuseblk(void)
1276 {
1277 	unregister_filesystem(&fuseblk_fs_type);
1278 }
1279 #else
1280 static inline int register_fuseblk(void)
1281 {
1282 	return 0;
1283 }
1284 
1285 static inline void unregister_fuseblk(void)
1286 {
1287 }
1288 #endif
1289 
1290 static void fuse_inode_init_once(void *foo)
1291 {
1292 	struct inode *inode = foo;
1293 
1294 	inode_init_once(inode);
1295 }
1296 
1297 static int __init fuse_fs_init(void)
1298 {
1299 	int err;
1300 
1301 	fuse_inode_cachep = kmem_cache_create("fuse_inode",
1302 			sizeof(struct fuse_inode), 0,
1303 			SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1304 			fuse_inode_init_once);
1305 	err = -ENOMEM;
1306 	if (!fuse_inode_cachep)
1307 		goto out;
1308 
1309 	err = register_fuseblk();
1310 	if (err)
1311 		goto out2;
1312 
1313 	err = register_filesystem(&fuse_fs_type);
1314 	if (err)
1315 		goto out3;
1316 
1317 	return 0;
1318 
1319  out3:
1320 	unregister_fuseblk();
1321  out2:
1322 	kmem_cache_destroy(fuse_inode_cachep);
1323  out:
1324 	return err;
1325 }
1326 
1327 static void fuse_fs_cleanup(void)
1328 {
1329 	unregister_filesystem(&fuse_fs_type);
1330 	unregister_fuseblk();
1331 
1332 	/*
1333 	 * Make sure all delayed rcu free inodes are flushed before we
1334 	 * destroy cache.
1335 	 */
1336 	rcu_barrier();
1337 	kmem_cache_destroy(fuse_inode_cachep);
1338 }
1339 
1340 static struct kobject *fuse_kobj;
1341 
1342 static int fuse_sysfs_init(void)
1343 {
1344 	int err;
1345 
1346 	fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1347 	if (!fuse_kobj) {
1348 		err = -ENOMEM;
1349 		goto out_err;
1350 	}
1351 
1352 	err = sysfs_create_mount_point(fuse_kobj, "connections");
1353 	if (err)
1354 		goto out_fuse_unregister;
1355 
1356 	return 0;
1357 
1358  out_fuse_unregister:
1359 	kobject_put(fuse_kobj);
1360  out_err:
1361 	return err;
1362 }
1363 
1364 static void fuse_sysfs_cleanup(void)
1365 {
1366 	sysfs_remove_mount_point(fuse_kobj, "connections");
1367 	kobject_put(fuse_kobj);
1368 }
1369 
1370 static int __init fuse_init(void)
1371 {
1372 	int res;
1373 
1374 	printk(KERN_INFO "fuse init (API version %i.%i)\n",
1375 	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1376 
1377 	INIT_LIST_HEAD(&fuse_conn_list);
1378 	res = fuse_fs_init();
1379 	if (res)
1380 		goto err;
1381 
1382 	res = fuse_dev_init();
1383 	if (res)
1384 		goto err_fs_cleanup;
1385 
1386 	res = fuse_sysfs_init();
1387 	if (res)
1388 		goto err_dev_cleanup;
1389 
1390 	res = fuse_ctl_init();
1391 	if (res)
1392 		goto err_sysfs_cleanup;
1393 
1394 	sanitize_global_limit(&max_user_bgreq);
1395 	sanitize_global_limit(&max_user_congthresh);
1396 
1397 	return 0;
1398 
1399  err_sysfs_cleanup:
1400 	fuse_sysfs_cleanup();
1401  err_dev_cleanup:
1402 	fuse_dev_cleanup();
1403  err_fs_cleanup:
1404 	fuse_fs_cleanup();
1405  err:
1406 	return res;
1407 }
1408 
1409 static void __exit fuse_exit(void)
1410 {
1411 	printk(KERN_DEBUG "fuse exit\n");
1412 
1413 	fuse_ctl_cleanup();
1414 	fuse_sysfs_cleanup();
1415 	fuse_fs_cleanup();
1416 	fuse_dev_cleanup();
1417 }
1418 
1419 module_init(fuse_init);
1420 module_exit(fuse_exit);
1421