xref: /openbmc/linux/fs/fuse/inode.c (revision 44e2971f)
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 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 = timespec64_to_timespec(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), false);
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, false);
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 			  struct user_namespace *user_ns)
482 {
483 	char *p;
484 	memset(d, 0, sizeof(struct fuse_mount_data));
485 	d->max_read = ~0;
486 	d->blksize = FUSE_DEFAULT_BLKSIZE;
487 
488 	while ((p = strsep(&opt, ",")) != NULL) {
489 		int token;
490 		int value;
491 		unsigned uv;
492 		substring_t args[MAX_OPT_ARGS];
493 		if (!*p)
494 			continue;
495 
496 		token = match_token(p, tokens, args);
497 		switch (token) {
498 		case OPT_FD:
499 			if (match_int(&args[0], &value))
500 				return 0;
501 			d->fd = value;
502 			d->fd_present = 1;
503 			break;
504 
505 		case OPT_ROOTMODE:
506 			if (match_octal(&args[0], &value))
507 				return 0;
508 			if (!fuse_valid_type(value))
509 				return 0;
510 			d->rootmode = value;
511 			d->rootmode_present = 1;
512 			break;
513 
514 		case OPT_USER_ID:
515 			if (fuse_match_uint(&args[0], &uv))
516 				return 0;
517 			d->user_id = make_kuid(user_ns, uv);
518 			if (!uid_valid(d->user_id))
519 				return 0;
520 			d->user_id_present = 1;
521 			break;
522 
523 		case OPT_GROUP_ID:
524 			if (fuse_match_uint(&args[0], &uv))
525 				return 0;
526 			d->group_id = make_kgid(user_ns, uv);
527 			if (!gid_valid(d->group_id))
528 				return 0;
529 			d->group_id_present = 1;
530 			break;
531 
532 		case OPT_DEFAULT_PERMISSIONS:
533 			d->default_permissions = 1;
534 			break;
535 
536 		case OPT_ALLOW_OTHER:
537 			d->allow_other = 1;
538 			break;
539 
540 		case OPT_MAX_READ:
541 			if (match_int(&args[0], &value))
542 				return 0;
543 			d->max_read = value;
544 			break;
545 
546 		case OPT_BLKSIZE:
547 			if (!is_bdev || match_int(&args[0], &value))
548 				return 0;
549 			d->blksize = value;
550 			break;
551 
552 		default:
553 			return 0;
554 		}
555 	}
556 
557 	if (!d->fd_present || !d->rootmode_present ||
558 	    !d->user_id_present || !d->group_id_present)
559 		return 0;
560 
561 	return 1;
562 }
563 
564 static int fuse_show_options(struct seq_file *m, struct dentry *root)
565 {
566 	struct super_block *sb = root->d_sb;
567 	struct fuse_conn *fc = get_fuse_conn_super(sb);
568 
569 	seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id));
570 	seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id));
571 	if (fc->default_permissions)
572 		seq_puts(m, ",default_permissions");
573 	if (fc->allow_other)
574 		seq_puts(m, ",allow_other");
575 	if (fc->max_read != ~0)
576 		seq_printf(m, ",max_read=%u", fc->max_read);
577 	if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
578 		seq_printf(m, ",blksize=%lu", sb->s_blocksize);
579 	return 0;
580 }
581 
582 static void fuse_iqueue_init(struct fuse_iqueue *fiq)
583 {
584 	memset(fiq, 0, sizeof(struct fuse_iqueue));
585 	init_waitqueue_head(&fiq->waitq);
586 	INIT_LIST_HEAD(&fiq->pending);
587 	INIT_LIST_HEAD(&fiq->interrupts);
588 	fiq->forget_list_tail = &fiq->forget_list_head;
589 	fiq->connected = 1;
590 }
591 
592 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
593 {
594 	memset(fpq, 0, sizeof(struct fuse_pqueue));
595 	spin_lock_init(&fpq->lock);
596 	INIT_LIST_HEAD(&fpq->processing);
597 	INIT_LIST_HEAD(&fpq->io);
598 	fpq->connected = 1;
599 }
600 
601 void fuse_conn_init(struct fuse_conn *fc, struct user_namespace *user_ns)
602 {
603 	memset(fc, 0, sizeof(*fc));
604 	spin_lock_init(&fc->lock);
605 	init_rwsem(&fc->killsb);
606 	refcount_set(&fc->count, 1);
607 	atomic_set(&fc->dev_count, 1);
608 	init_waitqueue_head(&fc->blocked_waitq);
609 	init_waitqueue_head(&fc->reserved_req_waitq);
610 	fuse_iqueue_init(&fc->iq);
611 	INIT_LIST_HEAD(&fc->bg_queue);
612 	INIT_LIST_HEAD(&fc->entry);
613 	INIT_LIST_HEAD(&fc->devices);
614 	atomic_set(&fc->num_waiting, 0);
615 	fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
616 	fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
617 	fc->khctr = 0;
618 	fc->polled_files = RB_ROOT;
619 	fc->blocked = 0;
620 	fc->initialized = 0;
621 	fc->connected = 1;
622 	fc->attr_version = 1;
623 	get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
624 	fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
625 	fc->user_ns = get_user_ns(user_ns);
626 }
627 EXPORT_SYMBOL_GPL(fuse_conn_init);
628 
629 void fuse_conn_put(struct fuse_conn *fc)
630 {
631 	if (refcount_dec_and_test(&fc->count)) {
632 		if (fc->destroy_req)
633 			fuse_request_free(fc->destroy_req);
634 		put_pid_ns(fc->pid_ns);
635 		put_user_ns(fc->user_ns);
636 		fc->release(fc);
637 	}
638 }
639 EXPORT_SYMBOL_GPL(fuse_conn_put);
640 
641 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
642 {
643 	refcount_inc(&fc->count);
644 	return fc;
645 }
646 EXPORT_SYMBOL_GPL(fuse_conn_get);
647 
648 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
649 {
650 	struct fuse_attr attr;
651 	memset(&attr, 0, sizeof(attr));
652 
653 	attr.mode = mode;
654 	attr.ino = FUSE_ROOT_ID;
655 	attr.nlink = 1;
656 	return fuse_iget(sb, 1, 0, &attr, 0, 0);
657 }
658 
659 struct fuse_inode_handle {
660 	u64 nodeid;
661 	u32 generation;
662 };
663 
664 static struct dentry *fuse_get_dentry(struct super_block *sb,
665 				      struct fuse_inode_handle *handle)
666 {
667 	struct fuse_conn *fc = get_fuse_conn_super(sb);
668 	struct inode *inode;
669 	struct dentry *entry;
670 	int err = -ESTALE;
671 
672 	if (handle->nodeid == 0)
673 		goto out_err;
674 
675 	inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
676 	if (!inode) {
677 		struct fuse_entry_out outarg;
678 		const struct qstr name = QSTR_INIT(".", 1);
679 
680 		if (!fc->export_support)
681 			goto out_err;
682 
683 		err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
684 				       &inode);
685 		if (err && err != -ENOENT)
686 			goto out_err;
687 		if (err || !inode) {
688 			err = -ESTALE;
689 			goto out_err;
690 		}
691 		err = -EIO;
692 		if (get_node_id(inode) != handle->nodeid)
693 			goto out_iput;
694 	}
695 	err = -ESTALE;
696 	if (inode->i_generation != handle->generation)
697 		goto out_iput;
698 
699 	entry = d_obtain_alias(inode);
700 	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
701 		fuse_invalidate_entry_cache(entry);
702 
703 	return entry;
704 
705  out_iput:
706 	iput(inode);
707  out_err:
708 	return ERR_PTR(err);
709 }
710 
711 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
712 			   struct inode *parent)
713 {
714 	int len = parent ? 6 : 3;
715 	u64 nodeid;
716 	u32 generation;
717 
718 	if (*max_len < len) {
719 		*max_len = len;
720 		return  FILEID_INVALID;
721 	}
722 
723 	nodeid = get_fuse_inode(inode)->nodeid;
724 	generation = inode->i_generation;
725 
726 	fh[0] = (u32)(nodeid >> 32);
727 	fh[1] = (u32)(nodeid & 0xffffffff);
728 	fh[2] = generation;
729 
730 	if (parent) {
731 		nodeid = get_fuse_inode(parent)->nodeid;
732 		generation = parent->i_generation;
733 
734 		fh[3] = (u32)(nodeid >> 32);
735 		fh[4] = (u32)(nodeid & 0xffffffff);
736 		fh[5] = generation;
737 	}
738 
739 	*max_len = len;
740 	return parent ? 0x82 : 0x81;
741 }
742 
743 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
744 		struct fid *fid, int fh_len, int fh_type)
745 {
746 	struct fuse_inode_handle handle;
747 
748 	if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
749 		return NULL;
750 
751 	handle.nodeid = (u64) fid->raw[0] << 32;
752 	handle.nodeid |= (u64) fid->raw[1];
753 	handle.generation = fid->raw[2];
754 	return fuse_get_dentry(sb, &handle);
755 }
756 
757 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
758 		struct fid *fid, int fh_len, int fh_type)
759 {
760 	struct fuse_inode_handle parent;
761 
762 	if (fh_type != 0x82 || fh_len < 6)
763 		return NULL;
764 
765 	parent.nodeid = (u64) fid->raw[3] << 32;
766 	parent.nodeid |= (u64) fid->raw[4];
767 	parent.generation = fid->raw[5];
768 	return fuse_get_dentry(sb, &parent);
769 }
770 
771 static struct dentry *fuse_get_parent(struct dentry *child)
772 {
773 	struct inode *child_inode = d_inode(child);
774 	struct fuse_conn *fc = get_fuse_conn(child_inode);
775 	struct inode *inode;
776 	struct dentry *parent;
777 	struct fuse_entry_out outarg;
778 	const struct qstr name = QSTR_INIT("..", 2);
779 	int err;
780 
781 	if (!fc->export_support)
782 		return ERR_PTR(-ESTALE);
783 
784 	err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
785 			       &name, &outarg, &inode);
786 	if (err) {
787 		if (err == -ENOENT)
788 			return ERR_PTR(-ESTALE);
789 		return ERR_PTR(err);
790 	}
791 
792 	parent = d_obtain_alias(inode);
793 	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
794 		fuse_invalidate_entry_cache(parent);
795 
796 	return parent;
797 }
798 
799 static const struct export_operations fuse_export_operations = {
800 	.fh_to_dentry	= fuse_fh_to_dentry,
801 	.fh_to_parent	= fuse_fh_to_parent,
802 	.encode_fh	= fuse_encode_fh,
803 	.get_parent	= fuse_get_parent,
804 };
805 
806 static const struct super_operations fuse_super_operations = {
807 	.alloc_inode    = fuse_alloc_inode,
808 	.destroy_inode  = fuse_destroy_inode,
809 	.evict_inode	= fuse_evict_inode,
810 	.write_inode	= fuse_write_inode,
811 	.drop_inode	= generic_delete_inode,
812 	.remount_fs	= fuse_remount_fs,
813 	.put_super	= fuse_put_super,
814 	.umount_begin	= fuse_umount_begin,
815 	.statfs		= fuse_statfs,
816 	.show_options	= fuse_show_options,
817 };
818 
819 static void sanitize_global_limit(unsigned *limit)
820 {
821 	if (*limit == 0)
822 		*limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
823 			 sizeof(struct fuse_req);
824 
825 	if (*limit >= 1 << 16)
826 		*limit = (1 << 16) - 1;
827 }
828 
829 static int set_global_limit(const char *val, const struct kernel_param *kp)
830 {
831 	int rv;
832 
833 	rv = param_set_uint(val, kp);
834 	if (rv)
835 		return rv;
836 
837 	sanitize_global_limit((unsigned *)kp->arg);
838 
839 	return 0;
840 }
841 
842 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
843 {
844 	int cap_sys_admin = capable(CAP_SYS_ADMIN);
845 
846 	if (arg->minor < 13)
847 		return;
848 
849 	sanitize_global_limit(&max_user_bgreq);
850 	sanitize_global_limit(&max_user_congthresh);
851 
852 	if (arg->max_background) {
853 		fc->max_background = arg->max_background;
854 
855 		if (!cap_sys_admin && fc->max_background > max_user_bgreq)
856 			fc->max_background = max_user_bgreq;
857 	}
858 	if (arg->congestion_threshold) {
859 		fc->congestion_threshold = arg->congestion_threshold;
860 
861 		if (!cap_sys_admin &&
862 		    fc->congestion_threshold > max_user_congthresh)
863 			fc->congestion_threshold = max_user_congthresh;
864 	}
865 }
866 
867 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
868 {
869 	struct fuse_init_out *arg = &req->misc.init_out;
870 
871 	if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
872 		fc->conn_error = 1;
873 	else {
874 		unsigned long ra_pages;
875 
876 		process_init_limits(fc, arg);
877 
878 		if (arg->minor >= 6) {
879 			ra_pages = arg->max_readahead / PAGE_SIZE;
880 			if (arg->flags & FUSE_ASYNC_READ)
881 				fc->async_read = 1;
882 			if (!(arg->flags & FUSE_POSIX_LOCKS))
883 				fc->no_lock = 1;
884 			if (arg->minor >= 17) {
885 				if (!(arg->flags & FUSE_FLOCK_LOCKS))
886 					fc->no_flock = 1;
887 			} else {
888 				if (!(arg->flags & FUSE_POSIX_LOCKS))
889 					fc->no_flock = 1;
890 			}
891 			if (arg->flags & FUSE_ATOMIC_O_TRUNC)
892 				fc->atomic_o_trunc = 1;
893 			if (arg->minor >= 9) {
894 				/* LOOKUP has dependency on proto version */
895 				if (arg->flags & FUSE_EXPORT_SUPPORT)
896 					fc->export_support = 1;
897 			}
898 			if (arg->flags & FUSE_BIG_WRITES)
899 				fc->big_writes = 1;
900 			if (arg->flags & FUSE_DONT_MASK)
901 				fc->dont_mask = 1;
902 			if (arg->flags & FUSE_AUTO_INVAL_DATA)
903 				fc->auto_inval_data = 1;
904 			if (arg->flags & FUSE_DO_READDIRPLUS) {
905 				fc->do_readdirplus = 1;
906 				if (arg->flags & FUSE_READDIRPLUS_AUTO)
907 					fc->readdirplus_auto = 1;
908 			}
909 			if (arg->flags & FUSE_ASYNC_DIO)
910 				fc->async_dio = 1;
911 			if (arg->flags & FUSE_WRITEBACK_CACHE)
912 				fc->writeback_cache = 1;
913 			if (arg->flags & FUSE_PARALLEL_DIROPS)
914 				fc->parallel_dirops = 1;
915 			if (arg->flags & FUSE_HANDLE_KILLPRIV)
916 				fc->handle_killpriv = 1;
917 			if (arg->time_gran && arg->time_gran <= 1000000000)
918 				fc->sb->s_time_gran = arg->time_gran;
919 			if ((arg->flags & FUSE_POSIX_ACL)) {
920 				fc->default_permissions = 1;
921 				fc->posix_acl = 1;
922 				fc->sb->s_xattr = fuse_acl_xattr_handlers;
923 			}
924 			if (arg->flags & FUSE_ABORT_ERROR)
925 				fc->abort_err = 1;
926 		} else {
927 			ra_pages = fc->max_read / PAGE_SIZE;
928 			fc->no_lock = 1;
929 			fc->no_flock = 1;
930 		}
931 
932 		fc->sb->s_bdi->ra_pages =
933 				min(fc->sb->s_bdi->ra_pages, ra_pages);
934 		fc->minor = arg->minor;
935 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
936 		fc->max_write = max_t(unsigned, 4096, fc->max_write);
937 		fc->conn_init = 1;
938 	}
939 	fuse_set_initialized(fc);
940 	wake_up_all(&fc->blocked_waitq);
941 }
942 
943 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
944 {
945 	struct fuse_init_in *arg = &req->misc.init_in;
946 
947 	arg->major = FUSE_KERNEL_VERSION;
948 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
949 	arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
950 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
951 		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
952 		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
953 		FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
954 		FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
955 		FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
956 		FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
957 		FUSE_ABORT_ERROR;
958 	req->in.h.opcode = FUSE_INIT;
959 	req->in.numargs = 1;
960 	req->in.args[0].size = sizeof(*arg);
961 	req->in.args[0].value = arg;
962 	req->out.numargs = 1;
963 	/* Variable length argument used for backward compatibility
964 	   with interface version < 7.5.  Rest of init_out is zeroed
965 	   by do_get_request(), so a short reply is not a problem */
966 	req->out.argvar = 1;
967 	req->out.args[0].size = sizeof(struct fuse_init_out);
968 	req->out.args[0].value = &req->misc.init_out;
969 	req->end = process_init_reply;
970 	fuse_request_send_background(fc, req);
971 }
972 
973 static void fuse_free_conn(struct fuse_conn *fc)
974 {
975 	WARN_ON(!list_empty(&fc->devices));
976 	kfree_rcu(fc, rcu);
977 }
978 
979 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
980 {
981 	int err;
982 	char *suffix = "";
983 
984 	if (sb->s_bdev) {
985 		suffix = "-fuseblk";
986 		/*
987 		 * sb->s_bdi points to blkdev's bdi however we want to redirect
988 		 * it to our private bdi...
989 		 */
990 		bdi_put(sb->s_bdi);
991 		sb->s_bdi = &noop_backing_dev_info;
992 	}
993 	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
994 				   MINOR(fc->dev), suffix);
995 	if (err)
996 		return err;
997 
998 	sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
999 	/* fuse does it's own writeback accounting */
1000 	sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
1001 
1002 	/*
1003 	 * For a single fuse filesystem use max 1% of dirty +
1004 	 * writeback threshold.
1005 	 *
1006 	 * This gives about 1M of write buffer for memory maps on a
1007 	 * machine with 1G and 10% dirty_ratio, which should be more
1008 	 * than enough.
1009 	 *
1010 	 * Privileged users can raise it by writing to
1011 	 *
1012 	 *    /sys/class/bdi/<bdi>/max_ratio
1013 	 */
1014 	bdi_set_max_ratio(sb->s_bdi, 1);
1015 
1016 	return 0;
1017 }
1018 
1019 struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc)
1020 {
1021 	struct fuse_dev *fud;
1022 
1023 	fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1024 	if (fud) {
1025 		fud->fc = fuse_conn_get(fc);
1026 		fuse_pqueue_init(&fud->pq);
1027 
1028 		spin_lock(&fc->lock);
1029 		list_add_tail(&fud->entry, &fc->devices);
1030 		spin_unlock(&fc->lock);
1031 	}
1032 
1033 	return fud;
1034 }
1035 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1036 
1037 void fuse_dev_free(struct fuse_dev *fud)
1038 {
1039 	struct fuse_conn *fc = fud->fc;
1040 
1041 	if (fc) {
1042 		spin_lock(&fc->lock);
1043 		list_del(&fud->entry);
1044 		spin_unlock(&fc->lock);
1045 
1046 		fuse_conn_put(fc);
1047 	}
1048 	kfree(fud);
1049 }
1050 EXPORT_SYMBOL_GPL(fuse_dev_free);
1051 
1052 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
1053 {
1054 	struct fuse_dev *fud;
1055 	struct fuse_conn *fc;
1056 	struct inode *root;
1057 	struct fuse_mount_data d;
1058 	struct file *file;
1059 	struct dentry *root_dentry;
1060 	struct fuse_req *init_req;
1061 	int err;
1062 	int is_bdev = sb->s_bdev != NULL;
1063 
1064 	err = -EINVAL;
1065 	if (sb->s_flags & SB_MANDLOCK)
1066 		goto err;
1067 
1068 	sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1069 
1070 	if (!parse_fuse_opt(data, &d, is_bdev, sb->s_user_ns))
1071 		goto err;
1072 
1073 	if (is_bdev) {
1074 #ifdef CONFIG_BLOCK
1075 		err = -EINVAL;
1076 		if (!sb_set_blocksize(sb, d.blksize))
1077 			goto err;
1078 #endif
1079 	} else {
1080 		sb->s_blocksize = PAGE_SIZE;
1081 		sb->s_blocksize_bits = PAGE_SHIFT;
1082 	}
1083 	sb->s_magic = FUSE_SUPER_MAGIC;
1084 	sb->s_op = &fuse_super_operations;
1085 	sb->s_xattr = fuse_xattr_handlers;
1086 	sb->s_maxbytes = MAX_LFS_FILESIZE;
1087 	sb->s_time_gran = 1;
1088 	sb->s_export_op = &fuse_export_operations;
1089 	sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1090 	if (sb->s_user_ns != &init_user_ns)
1091 		sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1092 
1093 	file = fget(d.fd);
1094 	err = -EINVAL;
1095 	if (!file)
1096 		goto err;
1097 
1098 	/*
1099 	 * Require mount to happen from the same user namespace which
1100 	 * opened /dev/fuse to prevent potential attacks.
1101 	 */
1102 	if (file->f_op != &fuse_dev_operations ||
1103 	    file->f_cred->user_ns != sb->s_user_ns)
1104 		goto err_fput;
1105 
1106 	/*
1107 	 * If we are not in the initial user namespace posix
1108 	 * acls must be translated.
1109 	 */
1110 	if (sb->s_user_ns != &init_user_ns)
1111 		sb->s_xattr = fuse_no_acl_xattr_handlers;
1112 
1113 	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1114 	err = -ENOMEM;
1115 	if (!fc)
1116 		goto err_fput;
1117 
1118 	fuse_conn_init(fc, sb->s_user_ns);
1119 	fc->release = fuse_free_conn;
1120 
1121 	fud = fuse_dev_alloc(fc);
1122 	if (!fud)
1123 		goto err_put_conn;
1124 
1125 	fc->dev = sb->s_dev;
1126 	fc->sb = sb;
1127 	err = fuse_bdi_init(fc, sb);
1128 	if (err)
1129 		goto err_dev_free;
1130 
1131 	/* Handle umasking inside the fuse code */
1132 	if (sb->s_flags & SB_POSIXACL)
1133 		fc->dont_mask = 1;
1134 	sb->s_flags |= SB_POSIXACL;
1135 
1136 	fc->default_permissions = d.default_permissions;
1137 	fc->allow_other = d.allow_other;
1138 	fc->user_id = d.user_id;
1139 	fc->group_id = d.group_id;
1140 	fc->max_read = max_t(unsigned, 4096, d.max_read);
1141 
1142 	/* Used by get_root_inode() */
1143 	sb->s_fs_info = fc;
1144 
1145 	err = -ENOMEM;
1146 	root = fuse_get_root_inode(sb, d.rootmode);
1147 	sb->s_d_op = &fuse_root_dentry_operations;
1148 	root_dentry = d_make_root(root);
1149 	if (!root_dentry)
1150 		goto err_dev_free;
1151 	/* Root dentry doesn't have .d_revalidate */
1152 	sb->s_d_op = &fuse_dentry_operations;
1153 
1154 	init_req = fuse_request_alloc(0);
1155 	if (!init_req)
1156 		goto err_put_root;
1157 	__set_bit(FR_BACKGROUND, &init_req->flags);
1158 
1159 	if (is_bdev) {
1160 		fc->destroy_req = fuse_request_alloc(0);
1161 		if (!fc->destroy_req)
1162 			goto err_free_init_req;
1163 	}
1164 
1165 	mutex_lock(&fuse_mutex);
1166 	err = -EINVAL;
1167 	if (file->private_data)
1168 		goto err_unlock;
1169 
1170 	err = fuse_ctl_add_conn(fc);
1171 	if (err)
1172 		goto err_unlock;
1173 
1174 	list_add_tail(&fc->entry, &fuse_conn_list);
1175 	sb->s_root = root_dentry;
1176 	file->private_data = fud;
1177 	mutex_unlock(&fuse_mutex);
1178 	/*
1179 	 * atomic_dec_and_test() in fput() provides the necessary
1180 	 * memory barrier for file->private_data to be visible on all
1181 	 * CPUs after this
1182 	 */
1183 	fput(file);
1184 
1185 	fuse_send_init(fc, init_req);
1186 
1187 	return 0;
1188 
1189  err_unlock:
1190 	mutex_unlock(&fuse_mutex);
1191  err_free_init_req:
1192 	fuse_request_free(init_req);
1193  err_put_root:
1194 	dput(root_dentry);
1195  err_dev_free:
1196 	fuse_dev_free(fud);
1197  err_put_conn:
1198 	fuse_conn_put(fc);
1199 	sb->s_fs_info = NULL;
1200  err_fput:
1201 	fput(file);
1202  err:
1203 	return err;
1204 }
1205 
1206 static struct dentry *fuse_mount(struct file_system_type *fs_type,
1207 		       int flags, const char *dev_name,
1208 		       void *raw_data)
1209 {
1210 	return mount_nodev(fs_type, flags, raw_data, fuse_fill_super);
1211 }
1212 
1213 static void fuse_kill_sb_anon(struct super_block *sb)
1214 {
1215 	struct fuse_conn *fc = get_fuse_conn_super(sb);
1216 
1217 	if (fc) {
1218 		down_write(&fc->killsb);
1219 		fc->sb = NULL;
1220 		up_write(&fc->killsb);
1221 	}
1222 
1223 	kill_anon_super(sb);
1224 }
1225 
1226 static struct file_system_type fuse_fs_type = {
1227 	.owner		= THIS_MODULE,
1228 	.name		= "fuse",
1229 	.fs_flags	= FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1230 	.mount		= fuse_mount,
1231 	.kill_sb	= fuse_kill_sb_anon,
1232 };
1233 MODULE_ALIAS_FS("fuse");
1234 
1235 #ifdef CONFIG_BLOCK
1236 static struct dentry *fuse_mount_blk(struct file_system_type *fs_type,
1237 			   int flags, const char *dev_name,
1238 			   void *raw_data)
1239 {
1240 	return mount_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super);
1241 }
1242 
1243 static void fuse_kill_sb_blk(struct super_block *sb)
1244 {
1245 	struct fuse_conn *fc = get_fuse_conn_super(sb);
1246 
1247 	if (fc) {
1248 		down_write(&fc->killsb);
1249 		fc->sb = NULL;
1250 		up_write(&fc->killsb);
1251 	}
1252 
1253 	kill_block_super(sb);
1254 }
1255 
1256 static struct file_system_type fuseblk_fs_type = {
1257 	.owner		= THIS_MODULE,
1258 	.name		= "fuseblk",
1259 	.mount		= fuse_mount_blk,
1260 	.kill_sb	= fuse_kill_sb_blk,
1261 	.fs_flags	= FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1262 };
1263 MODULE_ALIAS_FS("fuseblk");
1264 
1265 static inline int register_fuseblk(void)
1266 {
1267 	return register_filesystem(&fuseblk_fs_type);
1268 }
1269 
1270 static inline void unregister_fuseblk(void)
1271 {
1272 	unregister_filesystem(&fuseblk_fs_type);
1273 }
1274 #else
1275 static inline int register_fuseblk(void)
1276 {
1277 	return 0;
1278 }
1279 
1280 static inline void unregister_fuseblk(void)
1281 {
1282 }
1283 #endif
1284 
1285 static void fuse_inode_init_once(void *foo)
1286 {
1287 	struct inode *inode = foo;
1288 
1289 	inode_init_once(inode);
1290 }
1291 
1292 static int __init fuse_fs_init(void)
1293 {
1294 	int err;
1295 
1296 	fuse_inode_cachep = kmem_cache_create("fuse_inode",
1297 			sizeof(struct fuse_inode), 0,
1298 			SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1299 			fuse_inode_init_once);
1300 	err = -ENOMEM;
1301 	if (!fuse_inode_cachep)
1302 		goto out;
1303 
1304 	err = register_fuseblk();
1305 	if (err)
1306 		goto out2;
1307 
1308 	err = register_filesystem(&fuse_fs_type);
1309 	if (err)
1310 		goto out3;
1311 
1312 	return 0;
1313 
1314  out3:
1315 	unregister_fuseblk();
1316  out2:
1317 	kmem_cache_destroy(fuse_inode_cachep);
1318  out:
1319 	return err;
1320 }
1321 
1322 static void fuse_fs_cleanup(void)
1323 {
1324 	unregister_filesystem(&fuse_fs_type);
1325 	unregister_fuseblk();
1326 
1327 	/*
1328 	 * Make sure all delayed rcu free inodes are flushed before we
1329 	 * destroy cache.
1330 	 */
1331 	rcu_barrier();
1332 	kmem_cache_destroy(fuse_inode_cachep);
1333 }
1334 
1335 static struct kobject *fuse_kobj;
1336 
1337 static int fuse_sysfs_init(void)
1338 {
1339 	int err;
1340 
1341 	fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1342 	if (!fuse_kobj) {
1343 		err = -ENOMEM;
1344 		goto out_err;
1345 	}
1346 
1347 	err = sysfs_create_mount_point(fuse_kobj, "connections");
1348 	if (err)
1349 		goto out_fuse_unregister;
1350 
1351 	return 0;
1352 
1353  out_fuse_unregister:
1354 	kobject_put(fuse_kobj);
1355  out_err:
1356 	return err;
1357 }
1358 
1359 static void fuse_sysfs_cleanup(void)
1360 {
1361 	sysfs_remove_mount_point(fuse_kobj, "connections");
1362 	kobject_put(fuse_kobj);
1363 }
1364 
1365 static int __init fuse_init(void)
1366 {
1367 	int res;
1368 
1369 	printk(KERN_INFO "fuse init (API version %i.%i)\n",
1370 	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1371 
1372 	INIT_LIST_HEAD(&fuse_conn_list);
1373 	res = fuse_fs_init();
1374 	if (res)
1375 		goto err;
1376 
1377 	res = fuse_dev_init();
1378 	if (res)
1379 		goto err_fs_cleanup;
1380 
1381 	res = fuse_sysfs_init();
1382 	if (res)
1383 		goto err_dev_cleanup;
1384 
1385 	res = fuse_ctl_init();
1386 	if (res)
1387 		goto err_sysfs_cleanup;
1388 
1389 	sanitize_global_limit(&max_user_bgreq);
1390 	sanitize_global_limit(&max_user_congthresh);
1391 
1392 	return 0;
1393 
1394  err_sysfs_cleanup:
1395 	fuse_sysfs_cleanup();
1396  err_dev_cleanup:
1397 	fuse_dev_cleanup();
1398  err_fs_cleanup:
1399 	fuse_fs_cleanup();
1400  err:
1401 	return res;
1402 }
1403 
1404 static void __exit fuse_exit(void)
1405 {
1406 	printk(KERN_DEBUG "fuse exit\n");
1407 
1408 	fuse_ctl_cleanup();
1409 	fuse_sysfs_cleanup();
1410 	fuse_fs_cleanup();
1411 	fuse_dev_cleanup();
1412 }
1413 
1414 module_init(fuse_init);
1415 module_exit(fuse_exit);
1416