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/fs_context.h>
19 #include <linux/fs_parser.h>
20 #include <linux/statfs.h>
21 #include <linux/random.h>
22 #include <linux/sched.h>
23 #include <linux/exportfs.h>
24 #include <linux/posix_acl.h>
25 #include <linux/pid_namespace.h>
26 #include <uapi/linux/magic.h>
27
28 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
29 MODULE_DESCRIPTION("Filesystem in Userspace");
30 MODULE_LICENSE("GPL");
31
32 static struct kmem_cache *fuse_inode_cachep;
33 struct list_head fuse_conn_list;
34 DEFINE_MUTEX(fuse_mutex);
35
36 static int set_global_limit(const char *val, const struct kernel_param *kp);
37
38 unsigned max_user_bgreq;
39 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
40 &max_user_bgreq, 0644);
41 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
42 MODULE_PARM_DESC(max_user_bgreq,
43 "Global limit for the maximum number of backgrounded requests an "
44 "unprivileged user can set");
45
46 unsigned max_user_congthresh;
47 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
48 &max_user_congthresh, 0644);
49 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
50 MODULE_PARM_DESC(max_user_congthresh,
51 "Global limit for the maximum congestion threshold an "
52 "unprivileged user can set");
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 #ifdef CONFIG_BLOCK
63 static struct file_system_type fuseblk_fs_type;
64 #endif
65
66 struct fuse_forget_link *fuse_alloc_forget(void)
67 {
68 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
69 }
70
71 static struct fuse_submount_lookup *fuse_alloc_submount_lookup(void)
72 {
73 struct fuse_submount_lookup *sl;
74
75 sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT);
76 if (!sl)
77 return NULL;
78 sl->forget = fuse_alloc_forget();
79 if (!sl->forget)
80 goto out_free;
81
82 return sl;
83
84 out_free:
85 kfree(sl);
86 return NULL;
87 }
88
89 static struct inode *fuse_alloc_inode(struct super_block *sb)
90 {
91 struct fuse_inode *fi;
92
93 fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL);
94 if (!fi)
95 return NULL;
96
97 fi->i_time = 0;
98 fi->inval_mask = ~0;
99 fi->nodeid = 0;
100 fi->nlookup = 0;
101 fi->attr_version = 0;
102 fi->orig_ino = 0;
103 fi->state = 0;
104 fi->submount_lookup = NULL;
105 mutex_init(&fi->mutex);
106 spin_lock_init(&fi->lock);
107 fi->forget = fuse_alloc_forget();
108 if (!fi->forget)
109 goto out_free;
110
111 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
112 goto out_free_forget;
113
114 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
115 fuse_inode_backing_set(fi, NULL);
116
117 return &fi->inode;
118
119 out_free_forget:
120 kfree(fi->forget);
121 out_free:
122 kmem_cache_free(fuse_inode_cachep, fi);
123 return NULL;
124 }
125
126 static void fuse_free_inode(struct inode *inode)
127 {
128 struct fuse_inode *fi = get_fuse_inode(inode);
129
130 mutex_destroy(&fi->mutex);
131 kfree(fi->forget);
132 #ifdef CONFIG_FUSE_DAX
133 kfree(fi->dax);
134 #endif
135 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
136 fuse_backing_put(fuse_inode_backing(fi));
137
138 kmem_cache_free(fuse_inode_cachep, fi);
139 }
140
141 static void fuse_cleanup_submount_lookup(struct fuse_conn *fc,
142 struct fuse_submount_lookup *sl)
143 {
144 if (!refcount_dec_and_test(&sl->count))
145 return;
146
147 fuse_queue_forget(fc, sl->forget, sl->nodeid, 1);
148 sl->forget = NULL;
149 kfree(sl);
150 }
151
152 static void fuse_evict_inode(struct inode *inode)
153 {
154 struct fuse_inode *fi = get_fuse_inode(inode);
155
156 /* Will write inode on close/munmap and in all other dirtiers */
157 WARN_ON(inode->i_state & I_DIRTY_INODE);
158
159 truncate_inode_pages_final(&inode->i_data);
160 clear_inode(inode);
161 if (inode->i_sb->s_flags & SB_ACTIVE) {
162 struct fuse_conn *fc = get_fuse_conn(inode);
163
164 if (FUSE_IS_DAX(inode))
165 fuse_dax_inode_cleanup(inode);
166 if (fi->nlookup) {
167 fuse_queue_forget(fc, fi->forget, fi->nodeid,
168 fi->nlookup);
169 fi->forget = NULL;
170 }
171
172 if (fi->submount_lookup) {
173 fuse_cleanup_submount_lookup(fc, fi->submount_lookup);
174 fi->submount_lookup = NULL;
175 }
176 }
177 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
178 WARN_ON(fi->iocachectr != 0);
179 WARN_ON(!list_empty(&fi->write_files));
180 WARN_ON(!list_empty(&fi->queued_writes));
181 }
182 }
183
184 static int fuse_reconfigure(struct fs_context *fsc)
185 {
186 struct super_block *sb = fsc->root->d_sb;
187
188 sync_filesystem(sb);
189 if (fsc->sb_flags & SB_MANDLOCK)
190 return -EINVAL;
191
192 return 0;
193 }
194
195 /*
196 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
197 * so that it will fit.
198 */
199 static ino_t fuse_squash_ino(u64 ino64)
200 {
201 ino_t ino = (ino_t) ino64;
202 if (sizeof(ino_t) < sizeof(u64))
203 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
204 return ino;
205 }
206
207 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
208 struct fuse_statx *sx,
209 u64 attr_valid, u32 cache_mask)
210 {
211 struct fuse_conn *fc = get_fuse_conn(inode);
212 struct fuse_inode *fi = get_fuse_inode(inode);
213
214 lockdep_assert_held(&fi->lock);
215
216 fi->attr_version = atomic64_inc_return(&fc->attr_version);
217 fi->i_time = attr_valid;
218 /* Clear basic stats from invalid mask */
219 set_mask_bits(&fi->inval_mask, STATX_BASIC_STATS, 0);
220
221 inode->i_ino = fuse_squash_ino(attr->ino);
222 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
223 set_nlink(inode, attr->nlink);
224 inode->i_uid = make_kuid(fc->user_ns, attr->uid);
225 inode->i_gid = make_kgid(fc->user_ns, attr->gid);
226 inode->i_blocks = attr->blocks;
227
228 /* Sanitize nsecs */
229 attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1);
230 attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1);
231 attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1);
232
233 inode_set_atime(inode, attr->atime, attr->atimensec);
234 /* mtime from server may be stale due to local buffered write */
235 if (!(cache_mask & STATX_MTIME)) {
236 inode_set_mtime(inode, attr->mtime, attr->mtimensec);
237 }
238 if (!(cache_mask & STATX_CTIME)) {
239 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
240 }
241 if (sx) {
242 /* Sanitize nsecs */
243 sx->btime.tv_nsec =
244 min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
245
246 /*
247 * Btime has been queried, cache is valid (whether or not btime
248 * is available or not) so clear STATX_BTIME from inval_mask.
249 *
250 * Availability of the btime attribute is indicated in
251 * FUSE_I_BTIME
252 */
253 set_mask_bits(&fi->inval_mask, STATX_BTIME, 0);
254 if (sx->mask & STATX_BTIME) {
255 set_bit(FUSE_I_BTIME, &fi->state);
256 fi->i_btime.tv_sec = sx->btime.tv_sec;
257 fi->i_btime.tv_nsec = sx->btime.tv_nsec;
258 }
259 }
260
261 if (attr->blksize != 0)
262 inode->i_blkbits = ilog2(attr->blksize);
263 else
264 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
265
266 /*
267 * Don't set the sticky bit in i_mode, unless we want the VFS
268 * to check permissions. This prevents failures due to the
269 * check in may_delete().
270 */
271 fi->orig_i_mode = inode->i_mode;
272 if (!fc->default_permissions)
273 inode->i_mode &= ~S_ISVTX;
274
275 fi->orig_ino = attr->ino;
276
277 /*
278 * We are refreshing inode data and it is possible that another
279 * client set suid/sgid or security.capability xattr. So clear
280 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
281 * was set or if security.capability xattr was set. But we don't
282 * know if security.capability has been set or not. So clear it
283 * anyway. Its less efficient but should be safe.
284 */
285 inode->i_flags &= ~S_NOSEC;
286 }
287
288 u32 fuse_get_cache_mask(struct inode *inode)
289 {
290 struct fuse_conn *fc = get_fuse_conn(inode);
291
292 if (!fc->writeback_cache || !S_ISREG(inode->i_mode))
293 return 0;
294
295 return STATX_MTIME | STATX_CTIME | STATX_SIZE;
296 }
297
298 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
299 struct fuse_statx *sx,
300 u64 attr_valid, u64 attr_version)
301 {
302 struct fuse_conn *fc = get_fuse_conn(inode);
303 struct fuse_inode *fi = get_fuse_inode(inode);
304 u32 cache_mask;
305 loff_t oldsize;
306 struct timespec64 old_mtime;
307
308 spin_lock(&fi->lock);
309 /*
310 * In case of writeback_cache enabled, writes update mtime, ctime and
311 * may update i_size. In these cases trust the cached value in the
312 * inode.
313 */
314 cache_mask = fuse_get_cache_mask(inode);
315 if (cache_mask & STATX_SIZE)
316 attr->size = i_size_read(inode);
317
318 if (cache_mask & STATX_MTIME) {
319 attr->mtime = inode_get_mtime_sec(inode);
320 attr->mtimensec = inode_get_mtime_nsec(inode);
321 }
322 if (cache_mask & STATX_CTIME) {
323 attr->ctime = inode_get_ctime_sec(inode);
324 attr->ctimensec = inode_get_ctime_nsec(inode);
325 }
326
327 if ((attr_version != 0 && fi->attr_version > attr_version) ||
328 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
329 spin_unlock(&fi->lock);
330 return;
331 }
332
333 old_mtime = inode_get_mtime(inode);
334 fuse_change_attributes_common(inode, attr, sx, attr_valid, cache_mask);
335
336 oldsize = inode->i_size;
337 /*
338 * In case of writeback_cache enabled, the cached writes beyond EOF
339 * extend local i_size without keeping userspace server in sync. So,
340 * attr->size coming from server can be stale. We cannot trust it.
341 */
342 if (!(cache_mask & STATX_SIZE))
343 i_size_write(inode, attr->size);
344 spin_unlock(&fi->lock);
345
346 if (!cache_mask && S_ISREG(inode->i_mode)) {
347 bool inval = false;
348
349 if (oldsize != attr->size) {
350 truncate_pagecache(inode, attr->size);
351 if (!fc->explicit_inval_data)
352 inval = true;
353 } else if (fc->auto_inval_data) {
354 struct timespec64 new_mtime = {
355 .tv_sec = attr->mtime,
356 .tv_nsec = attr->mtimensec,
357 };
358
359 /*
360 * Auto inval mode also checks and invalidates if mtime
361 * has changed.
362 */
363 if (!timespec64_equal(&old_mtime, &new_mtime))
364 inval = true;
365 }
366
367 if (inval)
368 invalidate_inode_pages2(inode->i_mapping);
369 }
370
371 if (IS_ENABLED(CONFIG_FUSE_DAX))
372 fuse_dax_dontcache(inode, attr->flags);
373 }
374
375 static void fuse_init_submount_lookup(struct fuse_submount_lookup *sl,
376 u64 nodeid)
377 {
378 sl->nodeid = nodeid;
379 refcount_set(&sl->count, 1);
380 }
381
382 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr,
383 struct fuse_conn *fc)
384 {
385 inode->i_mode = attr->mode & S_IFMT;
386 inode->i_size = attr->size;
387 inode_set_mtime(inode, attr->mtime, attr->mtimensec);
388 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
389 if (S_ISREG(inode->i_mode)) {
390 fuse_init_common(inode);
391 fuse_init_file_inode(inode, attr->flags);
392 } else if (S_ISDIR(inode->i_mode))
393 fuse_init_dir(inode);
394 else if (S_ISLNK(inode->i_mode))
395 fuse_init_symlink(inode);
396 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
397 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
398 fuse_init_common(inode);
399 init_special_inode(inode, inode->i_mode,
400 new_decode_dev(attr->rdev));
401 } else
402 BUG();
403 /*
404 * Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL
405 * so they see the exact same behavior as before.
406 */
407 if (!fc->posix_acl)
408 inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
409 }
410
411 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
412 {
413 u64 nodeid = *(u64 *) _nodeidp;
414 if (get_node_id(inode) == nodeid)
415 return 1;
416 else
417 return 0;
418 }
419
420 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
421 {
422 u64 nodeid = *(u64 *) _nodeidp;
423 get_fuse_inode(inode)->nodeid = nodeid;
424 return 0;
425 }
426
427 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
428 int generation, struct fuse_attr *attr,
429 u64 attr_valid, u64 attr_version)
430 {
431 struct inode *inode;
432 struct fuse_inode *fi;
433 struct fuse_conn *fc = get_fuse_conn_super(sb);
434
435 /*
436 * Auto mount points get their node id from the submount root, which is
437 * not a unique identifier within this filesystem.
438 *
439 * To avoid conflicts, do not place submount points into the inode hash
440 * table.
441 */
442 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
443 S_ISDIR(attr->mode)) {
444 struct fuse_inode *fi;
445
446 inode = new_inode(sb);
447 if (!inode)
448 return NULL;
449
450 fuse_init_inode(inode, attr, fc);
451 fi = get_fuse_inode(inode);
452 fi->nodeid = nodeid;
453 fi->submount_lookup = fuse_alloc_submount_lookup();
454 if (!fi->submount_lookup) {
455 iput(inode);
456 return NULL;
457 }
458 /* Sets nlookup = 1 on fi->submount_lookup->nlookup */
459 fuse_init_submount_lookup(fi->submount_lookup, nodeid);
460 inode->i_flags |= S_AUTOMOUNT;
461 goto done;
462 }
463
464 retry:
465 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
466 if (!inode)
467 return NULL;
468
469 if ((inode->i_state & I_NEW)) {
470 inode->i_flags |= S_NOATIME;
471 if (!fc->writeback_cache || !S_ISREG(attr->mode))
472 inode->i_flags |= S_NOCMTIME;
473 inode->i_generation = generation;
474 fuse_init_inode(inode, attr, fc);
475 unlock_new_inode(inode);
476 } else if (fuse_stale_inode(inode, generation, attr)) {
477 /* nodeid was reused, any I/O on the old inode should fail */
478 fuse_make_bad(inode);
479 if (inode != d_inode(sb->s_root)) {
480 remove_inode_hash(inode);
481 iput(inode);
482 goto retry;
483 }
484 }
485 fi = get_fuse_inode(inode);
486 spin_lock(&fi->lock);
487 fi->nlookup++;
488 spin_unlock(&fi->lock);
489 done:
490 fuse_change_attributes(inode, attr, NULL, attr_valid, attr_version);
491
492 return inode;
493 }
494
495 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
496 struct fuse_mount **fm)
497 {
498 struct fuse_mount *fm_iter;
499 struct inode *inode;
500
501 WARN_ON(!rwsem_is_locked(&fc->killsb));
502 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
503 if (!fm_iter->sb)
504 continue;
505
506 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
507 if (inode) {
508 if (fm)
509 *fm = fm_iter;
510 return inode;
511 }
512 }
513
514 return NULL;
515 }
516
517 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
518 loff_t offset, loff_t len)
519 {
520 struct fuse_inode *fi;
521 struct inode *inode;
522 pgoff_t pg_start;
523 pgoff_t pg_end;
524
525 inode = fuse_ilookup(fc, nodeid, NULL);
526 if (!inode)
527 return -ENOENT;
528
529 fi = get_fuse_inode(inode);
530 spin_lock(&fi->lock);
531 fi->attr_version = atomic64_inc_return(&fc->attr_version);
532 spin_unlock(&fi->lock);
533
534 fuse_invalidate_attr(inode);
535 forget_all_cached_acls(inode);
536 if (offset >= 0) {
537 pg_start = offset >> PAGE_SHIFT;
538 if (len <= 0)
539 pg_end = -1;
540 else
541 pg_end = (offset + len - 1) >> PAGE_SHIFT;
542 invalidate_inode_pages2_range(inode->i_mapping,
543 pg_start, pg_end);
544 }
545 iput(inode);
546 return 0;
547 }
548
549 bool fuse_lock_inode(struct inode *inode)
550 {
551 bool locked = false;
552
553 if (!get_fuse_conn(inode)->parallel_dirops) {
554 mutex_lock(&get_fuse_inode(inode)->mutex);
555 locked = true;
556 }
557
558 return locked;
559 }
560
561 void fuse_unlock_inode(struct inode *inode, bool locked)
562 {
563 if (locked)
564 mutex_unlock(&get_fuse_inode(inode)->mutex);
565 }
566
567 static void fuse_umount_begin(struct super_block *sb)
568 {
569 struct fuse_conn *fc = get_fuse_conn_super(sb);
570
571 if (fc->no_force_umount)
572 return;
573
574 fuse_abort_conn(fc);
575
576 // Only retire block-device-based superblocks.
577 if (sb->s_bdev != NULL)
578 retire_super(sb);
579 }
580
581 static void fuse_send_destroy(struct fuse_mount *fm)
582 {
583 if (fm->fc->conn_init) {
584 FUSE_ARGS(args);
585
586 args.opcode = FUSE_DESTROY;
587 args.force = true;
588 args.nocreds = true;
589 fuse_simple_request(fm, &args);
590 }
591 }
592
593 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
594 {
595 stbuf->f_type = FUSE_SUPER_MAGIC;
596 stbuf->f_bsize = attr->bsize;
597 stbuf->f_frsize = attr->frsize;
598 stbuf->f_blocks = attr->blocks;
599 stbuf->f_bfree = attr->bfree;
600 stbuf->f_bavail = attr->bavail;
601 stbuf->f_files = attr->files;
602 stbuf->f_ffree = attr->ffree;
603 stbuf->f_namelen = attr->namelen;
604 /* fsid is left zero */
605 }
606
607 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
608 {
609 struct super_block *sb = dentry->d_sb;
610 struct fuse_mount *fm = get_fuse_mount_super(sb);
611 FUSE_ARGS(args);
612 struct fuse_statfs_out outarg;
613 int err;
614
615 if (!fuse_allow_current_process(fm->fc)) {
616 buf->f_type = FUSE_SUPER_MAGIC;
617 return 0;
618 }
619
620 memset(&outarg, 0, sizeof(outarg));
621 args.in_numargs = 0;
622 args.opcode = FUSE_STATFS;
623 args.nodeid = get_node_id(d_inode(dentry));
624 args.out_numargs = 1;
625 args.out_args[0].size = sizeof(outarg);
626 args.out_args[0].value = &outarg;
627 err = fuse_simple_request(fm, &args);
628 if (!err)
629 convert_fuse_statfs(buf, &outarg.st);
630 return err;
631 }
632
633 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
634 {
635 struct fuse_sync_bucket *bucket;
636
637 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
638 if (bucket) {
639 init_waitqueue_head(&bucket->waitq);
640 /* Initial active count */
641 atomic_set(&bucket->count, 1);
642 }
643 return bucket;
644 }
645
646 static void fuse_sync_fs_writes(struct fuse_conn *fc)
647 {
648 struct fuse_sync_bucket *bucket, *new_bucket;
649 int count;
650
651 new_bucket = fuse_sync_bucket_alloc();
652 spin_lock(&fc->lock);
653 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
654 count = atomic_read(&bucket->count);
655 WARN_ON(count < 1);
656 /* No outstanding writes? */
657 if (count == 1) {
658 spin_unlock(&fc->lock);
659 kfree(new_bucket);
660 return;
661 }
662
663 /*
664 * Completion of new bucket depends on completion of this bucket, so add
665 * one more count.
666 */
667 atomic_inc(&new_bucket->count);
668 rcu_assign_pointer(fc->curr_bucket, new_bucket);
669 spin_unlock(&fc->lock);
670 /*
671 * Drop initial active count. At this point if all writes in this and
672 * ancestor buckets complete, the count will go to zero and this task
673 * will be woken up.
674 */
675 atomic_dec(&bucket->count);
676
677 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
678
679 /* Drop temp count on descendant bucket */
680 fuse_sync_bucket_dec(new_bucket);
681 kfree_rcu(bucket, rcu);
682 }
683
684 static int fuse_sync_fs(struct super_block *sb, int wait)
685 {
686 struct fuse_mount *fm = get_fuse_mount_super(sb);
687 struct fuse_conn *fc = fm->fc;
688 struct fuse_syncfs_in inarg;
689 FUSE_ARGS(args);
690 int err;
691
692 /*
693 * Userspace cannot handle the wait == 0 case. Avoid a
694 * gratuitous roundtrip.
695 */
696 if (!wait)
697 return 0;
698
699 /* The filesystem is being unmounted. Nothing to do. */
700 if (!sb->s_root)
701 return 0;
702
703 if (!fc->sync_fs)
704 return 0;
705
706 fuse_sync_fs_writes(fc);
707
708 memset(&inarg, 0, sizeof(inarg));
709 args.in_numargs = 1;
710 args.in_args[0].size = sizeof(inarg);
711 args.in_args[0].value = &inarg;
712 args.opcode = FUSE_SYNCFS;
713 args.nodeid = get_node_id(sb->s_root->d_inode);
714 args.out_numargs = 0;
715
716 err = fuse_simple_request(fm, &args);
717 if (err == -ENOSYS) {
718 fc->sync_fs = 0;
719 err = 0;
720 }
721
722 return err;
723 }
724
725 enum {
726 OPT_SOURCE,
727 OPT_SUBTYPE,
728 OPT_FD,
729 OPT_ROOTMODE,
730 OPT_USER_ID,
731 OPT_GROUP_ID,
732 OPT_DEFAULT_PERMISSIONS,
733 OPT_ALLOW_OTHER,
734 OPT_MAX_READ,
735 OPT_BLKSIZE,
736 OPT_ERR
737 };
738
739 static const struct fs_parameter_spec fuse_fs_parameters[] = {
740 fsparam_string ("source", OPT_SOURCE),
741 fsparam_u32 ("fd", OPT_FD),
742 fsparam_u32oct ("rootmode", OPT_ROOTMODE),
743 fsparam_uid ("user_id", OPT_USER_ID),
744 fsparam_gid ("group_id", OPT_GROUP_ID),
745 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
746 fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
747 fsparam_u32 ("max_read", OPT_MAX_READ),
748 fsparam_u32 ("blksize", OPT_BLKSIZE),
749 fsparam_string ("subtype", OPT_SUBTYPE),
750 {}
751 };
752
753 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
754 {
755 struct fs_parse_result result;
756 struct fuse_fs_context *ctx = fsc->fs_private;
757 int opt;
758 kuid_t kuid;
759 kgid_t kgid;
760
761 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
762 /*
763 * Ignore options coming from mount(MS_REMOUNT) for backward
764 * compatibility.
765 */
766 if (fsc->oldapi)
767 return 0;
768
769 return invalfc(fsc, "No changes allowed in reconfigure");
770 }
771
772 opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
773 if (opt < 0)
774 return opt;
775
776 switch (opt) {
777 case OPT_SOURCE:
778 if (fsc->source)
779 return invalfc(fsc, "Multiple sources specified");
780 fsc->source = param->string;
781 param->string = NULL;
782 break;
783
784 case OPT_SUBTYPE:
785 if (ctx->subtype)
786 return invalfc(fsc, "Multiple subtypes specified");
787 ctx->subtype = param->string;
788 param->string = NULL;
789 return 0;
790
791 case OPT_FD:
792 ctx->fd = result.uint_32;
793 ctx->fd_present = true;
794 break;
795
796 case OPT_ROOTMODE:
797 if (!fuse_valid_type(result.uint_32))
798 return invalfc(fsc, "Invalid rootmode");
799 ctx->rootmode = result.uint_32;
800 ctx->rootmode_present = true;
801 break;
802
803 case OPT_USER_ID:
804 kuid = result.uid;
805 /*
806 * The requested uid must be representable in the
807 * filesystem's idmapping.
808 */
809 if (!kuid_has_mapping(fsc->user_ns, kuid))
810 return invalfc(fsc, "Invalid user_id");
811 ctx->user_id = kuid;
812 ctx->user_id_present = true;
813 break;
814
815 case OPT_GROUP_ID:
816 kgid = result.gid;
817 /*
818 * The requested gid must be representable in the
819 * filesystem's idmapping.
820 */
821 if (!kgid_has_mapping(fsc->user_ns, kgid))
822 return invalfc(fsc, "Invalid group_id");
823 ctx->group_id = kgid;
824 ctx->group_id_present = true;
825 break;
826
827 case OPT_DEFAULT_PERMISSIONS:
828 ctx->default_permissions = true;
829 break;
830
831 case OPT_ALLOW_OTHER:
832 ctx->allow_other = true;
833 break;
834
835 case OPT_MAX_READ:
836 ctx->max_read = result.uint_32;
837 break;
838
839 case OPT_BLKSIZE:
840 if (!ctx->is_bdev)
841 return invalfc(fsc, "blksize only supported for fuseblk");
842 ctx->blksize = result.uint_32;
843 break;
844
845 default:
846 return -EINVAL;
847 }
848
849 return 0;
850 }
851
852 static void fuse_free_fsc(struct fs_context *fsc)
853 {
854 struct fuse_fs_context *ctx = fsc->fs_private;
855
856 if (ctx) {
857 kfree(ctx->subtype);
858 kfree(ctx);
859 }
860 }
861
862 static int fuse_show_options(struct seq_file *m, struct dentry *root)
863 {
864 struct super_block *sb = root->d_sb;
865 struct fuse_conn *fc = get_fuse_conn_super(sb);
866
867 if (fc->legacy_opts_show) {
868 seq_printf(m, ",user_id=%u",
869 from_kuid_munged(fc->user_ns, fc->user_id));
870 seq_printf(m, ",group_id=%u",
871 from_kgid_munged(fc->user_ns, fc->group_id));
872 if (fc->default_permissions)
873 seq_puts(m, ",default_permissions");
874 if (fc->allow_other)
875 seq_puts(m, ",allow_other");
876 if (fc->max_read != ~0)
877 seq_printf(m, ",max_read=%u", fc->max_read);
878 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
879 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
880 }
881 #ifdef CONFIG_FUSE_DAX
882 if (fc->dax_mode == FUSE_DAX_ALWAYS)
883 seq_puts(m, ",dax=always");
884 else if (fc->dax_mode == FUSE_DAX_NEVER)
885 seq_puts(m, ",dax=never");
886 else if (fc->dax_mode == FUSE_DAX_INODE_USER)
887 seq_puts(m, ",dax=inode");
888 #endif
889
890 return 0;
891 }
892
893 static void fuse_iqueue_init(struct fuse_iqueue *fiq,
894 const struct fuse_iqueue_ops *ops,
895 void *priv)
896 {
897 memset(fiq, 0, sizeof(struct fuse_iqueue));
898 spin_lock_init(&fiq->lock);
899 init_waitqueue_head(&fiq->waitq);
900 INIT_LIST_HEAD(&fiq->pending);
901 INIT_LIST_HEAD(&fiq->interrupts);
902 fiq->forget_list_tail = &fiq->forget_list_head;
903 fiq->connected = 1;
904 fiq->ops = ops;
905 fiq->priv = priv;
906 }
907
908 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
909 {
910 unsigned int i;
911
912 spin_lock_init(&fpq->lock);
913 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
914 INIT_LIST_HEAD(&fpq->processing[i]);
915 INIT_LIST_HEAD(&fpq->io);
916 fpq->connected = 1;
917 }
918
919 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
920 struct user_namespace *user_ns,
921 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
922 {
923 memset(fc, 0, sizeof(*fc));
924 spin_lock_init(&fc->lock);
925 spin_lock_init(&fc->bg_lock);
926 init_rwsem(&fc->killsb);
927 refcount_set(&fc->count, 1);
928 atomic_set(&fc->dev_count, 1);
929 init_waitqueue_head(&fc->blocked_waitq);
930 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
931 INIT_LIST_HEAD(&fc->bg_queue);
932 INIT_LIST_HEAD(&fc->entry);
933 INIT_LIST_HEAD(&fc->devices);
934 atomic_set(&fc->num_waiting, 0);
935 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
936 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
937 atomic64_set(&fc->khctr, 0);
938 fc->polled_files = RB_ROOT;
939 fc->blocked = 0;
940 fc->initialized = 0;
941 fc->connected = 1;
942 atomic64_set(&fc->attr_version, 1);
943 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
944 fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
945 fc->user_ns = get_user_ns(user_ns);
946 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
947 fc->max_pages_limit = FUSE_MAX_MAX_PAGES;
948
949 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
950 fuse_backing_files_init(fc);
951
952 INIT_LIST_HEAD(&fc->mounts);
953 list_add(&fm->fc_entry, &fc->mounts);
954 fm->fc = fc;
955 }
956 EXPORT_SYMBOL_GPL(fuse_conn_init);
957
958 static void delayed_release(struct rcu_head *p)
959 {
960 struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu);
961
962 put_user_ns(fc->user_ns);
963 fc->release(fc);
964 }
965
966 void fuse_conn_put(struct fuse_conn *fc)
967 {
968 if (refcount_dec_and_test(&fc->count)) {
969 struct fuse_iqueue *fiq = &fc->iq;
970 struct fuse_sync_bucket *bucket;
971
972 if (IS_ENABLED(CONFIG_FUSE_DAX))
973 fuse_dax_conn_free(fc);
974 if (fiq->ops->release)
975 fiq->ops->release(fiq);
976 put_pid_ns(fc->pid_ns);
977 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
978 if (bucket) {
979 WARN_ON(atomic_read(&bucket->count) != 1);
980 kfree(bucket);
981 }
982 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
983 fuse_backing_files_free(fc);
984 call_rcu(&fc->rcu, delayed_release);
985 }
986 }
987 EXPORT_SYMBOL_GPL(fuse_conn_put);
988
989 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
990 {
991 refcount_inc(&fc->count);
992 return fc;
993 }
994 EXPORT_SYMBOL_GPL(fuse_conn_get);
995
996 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
997 {
998 struct fuse_attr attr;
999 memset(&attr, 0, sizeof(attr));
1000
1001 attr.mode = mode;
1002 attr.ino = FUSE_ROOT_ID;
1003 attr.nlink = 1;
1004 return fuse_iget(sb, FUSE_ROOT_ID, 0, &attr, 0, 0);
1005 }
1006
1007 struct fuse_inode_handle {
1008 u64 nodeid;
1009 u32 generation;
1010 };
1011
1012 static struct dentry *fuse_get_dentry(struct super_block *sb,
1013 struct fuse_inode_handle *handle)
1014 {
1015 struct fuse_conn *fc = get_fuse_conn_super(sb);
1016 struct inode *inode;
1017 struct dentry *entry;
1018 int err = -ESTALE;
1019
1020 if (handle->nodeid == 0)
1021 goto out_err;
1022
1023 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
1024 if (!inode) {
1025 struct fuse_entry_out outarg;
1026 const struct qstr name = QSTR_INIT(".", 1);
1027
1028 if (!fc->export_support)
1029 goto out_err;
1030
1031 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
1032 &inode);
1033 if (err && err != -ENOENT)
1034 goto out_err;
1035 if (err || !inode) {
1036 err = -ESTALE;
1037 goto out_err;
1038 }
1039 err = -EIO;
1040 if (get_node_id(inode) != handle->nodeid)
1041 goto out_iput;
1042 }
1043 err = -ESTALE;
1044 if (inode->i_generation != handle->generation)
1045 goto out_iput;
1046
1047 entry = d_obtain_alias(inode);
1048 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
1049 fuse_invalidate_entry_cache(entry);
1050
1051 return entry;
1052
1053 out_iput:
1054 iput(inode);
1055 out_err:
1056 return ERR_PTR(err);
1057 }
1058
1059 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
1060 struct inode *parent)
1061 {
1062 int len = parent ? 6 : 3;
1063 u64 nodeid;
1064 u32 generation;
1065
1066 if (*max_len < len) {
1067 *max_len = len;
1068 return FILEID_INVALID;
1069 }
1070
1071 nodeid = get_fuse_inode(inode)->nodeid;
1072 generation = inode->i_generation;
1073
1074 fh[0] = (u32)(nodeid >> 32);
1075 fh[1] = (u32)(nodeid & 0xffffffff);
1076 fh[2] = generation;
1077
1078 if (parent) {
1079 nodeid = get_fuse_inode(parent)->nodeid;
1080 generation = parent->i_generation;
1081
1082 fh[3] = (u32)(nodeid >> 32);
1083 fh[4] = (u32)(nodeid & 0xffffffff);
1084 fh[5] = generation;
1085 }
1086
1087 *max_len = len;
1088 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
1089 }
1090
1091 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
1092 struct fid *fid, int fh_len, int fh_type)
1093 {
1094 struct fuse_inode_handle handle;
1095
1096 if ((fh_type != FILEID_INO64_GEN &&
1097 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
1098 return NULL;
1099
1100 handle.nodeid = (u64) fid->raw[0] << 32;
1101 handle.nodeid |= (u64) fid->raw[1];
1102 handle.generation = fid->raw[2];
1103 return fuse_get_dentry(sb, &handle);
1104 }
1105
1106 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
1107 struct fid *fid, int fh_len, int fh_type)
1108 {
1109 struct fuse_inode_handle parent;
1110
1111 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
1112 return NULL;
1113
1114 parent.nodeid = (u64) fid->raw[3] << 32;
1115 parent.nodeid |= (u64) fid->raw[4];
1116 parent.generation = fid->raw[5];
1117 return fuse_get_dentry(sb, &parent);
1118 }
1119
1120 static struct dentry *fuse_get_parent(struct dentry *child)
1121 {
1122 struct inode *child_inode = d_inode(child);
1123 struct fuse_conn *fc = get_fuse_conn(child_inode);
1124 struct inode *inode;
1125 struct dentry *parent;
1126 struct fuse_entry_out outarg;
1127 int err;
1128
1129 if (!fc->export_support)
1130 return ERR_PTR(-ESTALE);
1131
1132 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
1133 &dotdot_name, &outarg, &inode);
1134 if (err) {
1135 if (err == -ENOENT)
1136 return ERR_PTR(-ESTALE);
1137 return ERR_PTR(err);
1138 }
1139
1140 parent = d_obtain_alias(inode);
1141 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
1142 fuse_invalidate_entry_cache(parent);
1143
1144 return parent;
1145 }
1146
1147 /* only for fid encoding; no support for file handle */
1148 static const struct export_operations fuse_export_fid_operations = {
1149 .encode_fh = fuse_encode_fh,
1150 };
1151
1152 static const struct export_operations fuse_export_operations = {
1153 .fh_to_dentry = fuse_fh_to_dentry,
1154 .fh_to_parent = fuse_fh_to_parent,
1155 .encode_fh = fuse_encode_fh,
1156 .get_parent = fuse_get_parent,
1157 };
1158
1159 static const struct super_operations fuse_super_operations = {
1160 .alloc_inode = fuse_alloc_inode,
1161 .free_inode = fuse_free_inode,
1162 .evict_inode = fuse_evict_inode,
1163 .write_inode = fuse_write_inode,
1164 .drop_inode = generic_delete_inode,
1165 .umount_begin = fuse_umount_begin,
1166 .statfs = fuse_statfs,
1167 .sync_fs = fuse_sync_fs,
1168 .show_options = fuse_show_options,
1169 };
1170
1171 static void sanitize_global_limit(unsigned *limit)
1172 {
1173 /*
1174 * The default maximum number of async requests is calculated to consume
1175 * 1/2^13 of the total memory, assuming 392 bytes per request.
1176 */
1177 if (*limit == 0)
1178 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
1179
1180 if (*limit >= 1 << 16)
1181 *limit = (1 << 16) - 1;
1182 }
1183
1184 static int set_global_limit(const char *val, const struct kernel_param *kp)
1185 {
1186 int rv;
1187
1188 rv = param_set_uint(val, kp);
1189 if (rv)
1190 return rv;
1191
1192 sanitize_global_limit((unsigned *)kp->arg);
1193
1194 return 0;
1195 }
1196
1197 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
1198 {
1199 int cap_sys_admin = capable(CAP_SYS_ADMIN);
1200
1201 if (arg->minor < 13)
1202 return;
1203
1204 sanitize_global_limit(&max_user_bgreq);
1205 sanitize_global_limit(&max_user_congthresh);
1206
1207 spin_lock(&fc->bg_lock);
1208 if (arg->max_background) {
1209 fc->max_background = arg->max_background;
1210
1211 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
1212 fc->max_background = max_user_bgreq;
1213 }
1214 if (arg->congestion_threshold) {
1215 fc->congestion_threshold = arg->congestion_threshold;
1216
1217 if (!cap_sys_admin &&
1218 fc->congestion_threshold > max_user_congthresh)
1219 fc->congestion_threshold = max_user_congthresh;
1220 }
1221 spin_unlock(&fc->bg_lock);
1222 }
1223
1224 struct fuse_init_args {
1225 struct fuse_args args;
1226 struct fuse_init_in in;
1227 struct fuse_init_out out;
1228 };
1229
1230 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
1231 int error)
1232 {
1233 struct fuse_conn *fc = fm->fc;
1234 struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
1235 struct fuse_init_out *arg = &ia->out;
1236 bool ok = true;
1237
1238 if (error || arg->major != FUSE_KERNEL_VERSION)
1239 ok = false;
1240 else {
1241 unsigned long ra_pages;
1242
1243 process_init_limits(fc, arg);
1244
1245 if (arg->minor >= 6) {
1246 u64 flags = arg->flags;
1247
1248 if (flags & FUSE_INIT_EXT)
1249 flags |= (u64) arg->flags2 << 32;
1250
1251 ra_pages = arg->max_readahead / PAGE_SIZE;
1252 if (flags & FUSE_ASYNC_READ)
1253 fc->async_read = 1;
1254 if (!(flags & FUSE_POSIX_LOCKS))
1255 fc->no_lock = 1;
1256 if (arg->minor >= 17) {
1257 if (!(flags & FUSE_FLOCK_LOCKS))
1258 fc->no_flock = 1;
1259 } else {
1260 if (!(flags & FUSE_POSIX_LOCKS))
1261 fc->no_flock = 1;
1262 }
1263 if (flags & FUSE_ATOMIC_O_TRUNC)
1264 fc->atomic_o_trunc = 1;
1265 if (arg->minor >= 9) {
1266 /* LOOKUP has dependency on proto version */
1267 if (flags & FUSE_EXPORT_SUPPORT)
1268 fc->export_support = 1;
1269 }
1270 if (flags & FUSE_BIG_WRITES)
1271 fc->big_writes = 1;
1272 if (flags & FUSE_DONT_MASK)
1273 fc->dont_mask = 1;
1274 if (flags & FUSE_AUTO_INVAL_DATA)
1275 fc->auto_inval_data = 1;
1276 else if (flags & FUSE_EXPLICIT_INVAL_DATA)
1277 fc->explicit_inval_data = 1;
1278 if (flags & FUSE_DO_READDIRPLUS) {
1279 fc->do_readdirplus = 1;
1280 if (flags & FUSE_READDIRPLUS_AUTO)
1281 fc->readdirplus_auto = 1;
1282 }
1283 if (flags & FUSE_ASYNC_DIO)
1284 fc->async_dio = 1;
1285 if (flags & FUSE_WRITEBACK_CACHE)
1286 fc->writeback_cache = 1;
1287 if (flags & FUSE_PARALLEL_DIROPS)
1288 fc->parallel_dirops = 1;
1289 if (flags & FUSE_HANDLE_KILLPRIV)
1290 fc->handle_killpriv = 1;
1291 if (arg->time_gran && arg->time_gran <= 1000000000)
1292 fm->sb->s_time_gran = arg->time_gran;
1293 if ((flags & FUSE_POSIX_ACL)) {
1294 fc->default_permissions = 1;
1295 fc->posix_acl = 1;
1296 }
1297 if (flags & FUSE_CACHE_SYMLINKS)
1298 fc->cache_symlinks = 1;
1299 if (flags & FUSE_ABORT_ERROR)
1300 fc->abort_err = 1;
1301 if (flags & FUSE_MAX_PAGES) {
1302 fc->max_pages =
1303 min_t(unsigned int, fc->max_pages_limit,
1304 max_t(unsigned int, arg->max_pages, 1));
1305 }
1306 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1307 if (flags & FUSE_MAP_ALIGNMENT &&
1308 !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1309 ok = false;
1310 }
1311 if (flags & FUSE_HAS_INODE_DAX)
1312 fc->inode_dax = 1;
1313 }
1314 if (flags & FUSE_HANDLE_KILLPRIV_V2) {
1315 fc->handle_killpriv_v2 = 1;
1316 fm->sb->s_flags |= SB_NOSEC;
1317 }
1318 if (flags & FUSE_SETXATTR_EXT)
1319 fc->setxattr_ext = 1;
1320 if (flags & FUSE_SECURITY_CTX)
1321 fc->init_security = 1;
1322 if (flags & FUSE_CREATE_SUPP_GROUP)
1323 fc->create_supp_group = 1;
1324 if (flags & FUSE_DIRECT_IO_ALLOW_MMAP)
1325 fc->direct_io_allow_mmap = 1;
1326 /*
1327 * max_stack_depth is the max stack depth of FUSE fs,
1328 * so it has to be at least 1 to support passthrough
1329 * to backing files.
1330 *
1331 * with max_stack_depth > 1, the backing files can be
1332 * on a stacked fs (e.g. overlayfs) themselves and with
1333 * max_stack_depth == 1, FUSE fs can be stacked as the
1334 * underlying fs of a stacked fs (e.g. overlayfs).
1335 *
1336 * Also don't allow the combination of FUSE_PASSTHROUGH
1337 * and FUSE_WRITEBACK_CACHE, current design doesn't handle
1338 * them together.
1339 */
1340 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) &&
1341 (flags & FUSE_PASSTHROUGH) &&
1342 arg->max_stack_depth > 0 &&
1343 arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH &&
1344 !(flags & FUSE_WRITEBACK_CACHE)) {
1345 fc->passthrough = 1;
1346 fc->max_stack_depth = arg->max_stack_depth;
1347 fm->sb->s_stack_depth = arg->max_stack_depth;
1348 }
1349 if (flags & FUSE_NO_EXPORT_SUPPORT)
1350 fm->sb->s_export_op = &fuse_export_fid_operations;
1351 } else {
1352 ra_pages = fc->max_read / PAGE_SIZE;
1353 fc->no_lock = 1;
1354 fc->no_flock = 1;
1355 }
1356
1357 fm->sb->s_bdi->ra_pages =
1358 min(fm->sb->s_bdi->ra_pages, ra_pages);
1359 fc->minor = arg->minor;
1360 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1361 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1362 fc->conn_init = 1;
1363 }
1364 kfree(ia);
1365
1366 if (!ok) {
1367 fc->conn_init = 0;
1368 fc->conn_error = 1;
1369 }
1370
1371 fuse_set_initialized(fc);
1372 wake_up_all(&fc->blocked_waitq);
1373 }
1374
1375 void fuse_send_init(struct fuse_mount *fm)
1376 {
1377 struct fuse_init_args *ia;
1378 u64 flags;
1379
1380 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1381
1382 ia->in.major = FUSE_KERNEL_VERSION;
1383 ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1384 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1385 flags =
1386 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1387 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1388 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1389 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1390 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1391 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1392 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1393 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1394 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1395 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT |
1396 FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP |
1397 FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP |
1398 FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND;
1399 #ifdef CONFIG_FUSE_DAX
1400 if (fm->fc->dax)
1401 flags |= FUSE_MAP_ALIGNMENT;
1402 if (fuse_is_inode_dax_mode(fm->fc->dax_mode))
1403 flags |= FUSE_HAS_INODE_DAX;
1404 #endif
1405 if (fm->fc->auto_submounts)
1406 flags |= FUSE_SUBMOUNTS;
1407 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
1408 flags |= FUSE_PASSTHROUGH;
1409
1410 ia->in.flags = flags;
1411 ia->in.flags2 = flags >> 32;
1412
1413 ia->args.opcode = FUSE_INIT;
1414 ia->args.in_numargs = 1;
1415 ia->args.in_args[0].size = sizeof(ia->in);
1416 ia->args.in_args[0].value = &ia->in;
1417 ia->args.out_numargs = 1;
1418 /* Variable length argument used for backward compatibility
1419 with interface version < 7.5. Rest of init_out is zeroed
1420 by do_get_request(), so a short reply is not a problem */
1421 ia->args.out_argvar = true;
1422 ia->args.out_args[0].size = sizeof(ia->out);
1423 ia->args.out_args[0].value = &ia->out;
1424 ia->args.force = true;
1425 ia->args.nocreds = true;
1426 ia->args.end = process_init_reply;
1427
1428 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1429 process_init_reply(fm, &ia->args, -ENOTCONN);
1430 }
1431 EXPORT_SYMBOL_GPL(fuse_send_init);
1432
1433 void fuse_free_conn(struct fuse_conn *fc)
1434 {
1435 WARN_ON(!list_empty(&fc->devices));
1436 kfree(fc);
1437 }
1438 EXPORT_SYMBOL_GPL(fuse_free_conn);
1439
1440 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1441 {
1442 int err;
1443 char *suffix = "";
1444
1445 if (sb->s_bdev) {
1446 suffix = "-fuseblk";
1447 /*
1448 * sb->s_bdi points to blkdev's bdi however we want to redirect
1449 * it to our private bdi...
1450 */
1451 bdi_put(sb->s_bdi);
1452 sb->s_bdi = &noop_backing_dev_info;
1453 }
1454 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1455 MINOR(fc->dev), suffix);
1456 if (err)
1457 return err;
1458
1459 /* fuse does it's own writeback accounting */
1460 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1461 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1462
1463 /*
1464 * For a single fuse filesystem use max 1% of dirty +
1465 * writeback threshold.
1466 *
1467 * This gives about 1M of write buffer for memory maps on a
1468 * machine with 1G and 10% dirty_ratio, which should be more
1469 * than enough.
1470 *
1471 * Privileged users can raise it by writing to
1472 *
1473 * /sys/class/bdi/<bdi>/max_ratio
1474 */
1475 bdi_set_max_ratio(sb->s_bdi, 1);
1476
1477 return 0;
1478 }
1479
1480 struct fuse_dev *fuse_dev_alloc(void)
1481 {
1482 struct fuse_dev *fud;
1483 struct list_head *pq;
1484
1485 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1486 if (!fud)
1487 return NULL;
1488
1489 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1490 if (!pq) {
1491 kfree(fud);
1492 return NULL;
1493 }
1494
1495 fud->pq.processing = pq;
1496 fuse_pqueue_init(&fud->pq);
1497
1498 return fud;
1499 }
1500 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1501
1502 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1503 {
1504 fud->fc = fuse_conn_get(fc);
1505 spin_lock(&fc->lock);
1506 list_add_tail(&fud->entry, &fc->devices);
1507 spin_unlock(&fc->lock);
1508 }
1509 EXPORT_SYMBOL_GPL(fuse_dev_install);
1510
1511 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1512 {
1513 struct fuse_dev *fud;
1514
1515 fud = fuse_dev_alloc();
1516 if (!fud)
1517 return NULL;
1518
1519 fuse_dev_install(fud, fc);
1520 return fud;
1521 }
1522 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1523
1524 void fuse_dev_free(struct fuse_dev *fud)
1525 {
1526 struct fuse_conn *fc = fud->fc;
1527
1528 if (fc) {
1529 spin_lock(&fc->lock);
1530 list_del(&fud->entry);
1531 spin_unlock(&fc->lock);
1532
1533 fuse_conn_put(fc);
1534 }
1535 kfree(fud->pq.processing);
1536 kfree(fud);
1537 }
1538 EXPORT_SYMBOL_GPL(fuse_dev_free);
1539
1540 static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1541 const struct fuse_inode *fi)
1542 {
1543 struct timespec64 atime = inode_get_atime(&fi->inode);
1544 struct timespec64 mtime = inode_get_mtime(&fi->inode);
1545 struct timespec64 ctime = inode_get_ctime(&fi->inode);
1546
1547 *attr = (struct fuse_attr){
1548 .ino = fi->inode.i_ino,
1549 .size = fi->inode.i_size,
1550 .blocks = fi->inode.i_blocks,
1551 .atime = atime.tv_sec,
1552 .mtime = mtime.tv_sec,
1553 .ctime = ctime.tv_sec,
1554 .atimensec = atime.tv_nsec,
1555 .mtimensec = mtime.tv_nsec,
1556 .ctimensec = ctime.tv_nsec,
1557 .mode = fi->inode.i_mode,
1558 .nlink = fi->inode.i_nlink,
1559 .uid = __kuid_val(fi->inode.i_uid),
1560 .gid = __kgid_val(fi->inode.i_gid),
1561 .rdev = fi->inode.i_rdev,
1562 .blksize = 1u << fi->inode.i_blkbits,
1563 };
1564 }
1565
1566 static void fuse_sb_defaults(struct super_block *sb)
1567 {
1568 sb->s_magic = FUSE_SUPER_MAGIC;
1569 sb->s_op = &fuse_super_operations;
1570 sb->s_xattr = fuse_xattr_handlers;
1571 sb->s_maxbytes = MAX_LFS_FILESIZE;
1572 sb->s_time_gran = 1;
1573 sb->s_export_op = &fuse_export_operations;
1574 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1575 if (sb->s_user_ns != &init_user_ns)
1576 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1577 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1578 }
1579
1580 static int fuse_fill_super_submount(struct super_block *sb,
1581 struct fuse_inode *parent_fi)
1582 {
1583 struct fuse_mount *fm = get_fuse_mount_super(sb);
1584 struct super_block *parent_sb = parent_fi->inode.i_sb;
1585 struct fuse_attr root_attr;
1586 struct inode *root;
1587 struct fuse_submount_lookup *sl;
1588 struct fuse_inode *fi;
1589
1590 fuse_sb_defaults(sb);
1591 fm->sb = sb;
1592
1593 WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1594 sb->s_bdi = bdi_get(parent_sb->s_bdi);
1595
1596 sb->s_xattr = parent_sb->s_xattr;
1597 sb->s_export_op = parent_sb->s_export_op;
1598 sb->s_time_gran = parent_sb->s_time_gran;
1599 sb->s_blocksize = parent_sb->s_blocksize;
1600 sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1601 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1602 if (parent_sb->s_subtype && !sb->s_subtype)
1603 return -ENOMEM;
1604
1605 fuse_fill_attr_from_inode(&root_attr, parent_fi);
1606 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1607 /*
1608 * This inode is just a duplicate, so it is not looked up and
1609 * its nlookup should not be incremented. fuse_iget() does
1610 * that, though, so undo it here.
1611 */
1612 fi = get_fuse_inode(root);
1613 fi->nlookup--;
1614
1615 sb->s_d_op = &fuse_dentry_operations;
1616 sb->s_root = d_make_root(root);
1617 if (!sb->s_root)
1618 return -ENOMEM;
1619
1620 /*
1621 * Grab the parent's submount_lookup pointer and take a
1622 * reference on the shared nlookup from the parent. This is to
1623 * prevent the last forget for this nodeid from getting
1624 * triggered until all users have finished with it.
1625 */
1626 sl = parent_fi->submount_lookup;
1627 WARN_ON(!sl);
1628 if (sl) {
1629 refcount_inc(&sl->count);
1630 fi->submount_lookup = sl;
1631 }
1632
1633 return 0;
1634 }
1635
1636 /* Filesystem context private data holds the FUSE inode of the mount point */
1637 static int fuse_get_tree_submount(struct fs_context *fsc)
1638 {
1639 struct fuse_mount *fm;
1640 struct fuse_inode *mp_fi = fsc->fs_private;
1641 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
1642 struct super_block *sb;
1643 int err;
1644
1645 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
1646 if (!fm)
1647 return -ENOMEM;
1648
1649 fm->fc = fuse_conn_get(fc);
1650 fsc->s_fs_info = fm;
1651 sb = sget_fc(fsc, NULL, set_anon_super_fc);
1652 if (fsc->s_fs_info)
1653 fuse_mount_destroy(fm);
1654 if (IS_ERR(sb))
1655 return PTR_ERR(sb);
1656
1657 /* Initialize superblock, making @mp_fi its root */
1658 err = fuse_fill_super_submount(sb, mp_fi);
1659 if (err) {
1660 deactivate_locked_super(sb);
1661 return err;
1662 }
1663
1664 down_write(&fc->killsb);
1665 list_add_tail(&fm->fc_entry, &fc->mounts);
1666 up_write(&fc->killsb);
1667
1668 sb->s_flags |= SB_ACTIVE;
1669 fsc->root = dget(sb->s_root);
1670
1671 return 0;
1672 }
1673
1674 static const struct fs_context_operations fuse_context_submount_ops = {
1675 .get_tree = fuse_get_tree_submount,
1676 };
1677
1678 int fuse_init_fs_context_submount(struct fs_context *fsc)
1679 {
1680 fsc->ops = &fuse_context_submount_ops;
1681 return 0;
1682 }
1683 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
1684
1685 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1686 {
1687 struct fuse_dev *fud = NULL;
1688 struct fuse_mount *fm = get_fuse_mount_super(sb);
1689 struct fuse_conn *fc = fm->fc;
1690 struct inode *root;
1691 struct dentry *root_dentry;
1692 int err;
1693
1694 err = -EINVAL;
1695 if (sb->s_flags & SB_MANDLOCK)
1696 goto err;
1697
1698 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
1699 fuse_sb_defaults(sb);
1700
1701 if (ctx->is_bdev) {
1702 #ifdef CONFIG_BLOCK
1703 err = -EINVAL;
1704 if (!sb_set_blocksize(sb, ctx->blksize))
1705 goto err;
1706 #endif
1707 } else {
1708 sb->s_blocksize = PAGE_SIZE;
1709 sb->s_blocksize_bits = PAGE_SHIFT;
1710 }
1711
1712 sb->s_subtype = ctx->subtype;
1713 ctx->subtype = NULL;
1714 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1715 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev);
1716 if (err)
1717 goto err;
1718 }
1719
1720 if (ctx->fudptr) {
1721 err = -ENOMEM;
1722 fud = fuse_dev_alloc_install(fc);
1723 if (!fud)
1724 goto err_free_dax;
1725 }
1726
1727 fc->dev = sb->s_dev;
1728 fm->sb = sb;
1729 err = fuse_bdi_init(fc, sb);
1730 if (err)
1731 goto err_dev_free;
1732
1733 /* Handle umasking inside the fuse code */
1734 if (sb->s_flags & SB_POSIXACL)
1735 fc->dont_mask = 1;
1736 sb->s_flags |= SB_POSIXACL;
1737
1738 fc->default_permissions = ctx->default_permissions;
1739 fc->allow_other = ctx->allow_other;
1740 fc->user_id = ctx->user_id;
1741 fc->group_id = ctx->group_id;
1742 fc->legacy_opts_show = ctx->legacy_opts_show;
1743 fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1744 fc->destroy = ctx->destroy;
1745 fc->no_control = ctx->no_control;
1746 fc->no_force_umount = ctx->no_force_umount;
1747
1748 err = -ENOMEM;
1749 root = fuse_get_root_inode(sb, ctx->rootmode);
1750 sb->s_d_op = &fuse_root_dentry_operations;
1751 root_dentry = d_make_root(root);
1752 if (!root_dentry)
1753 goto err_dev_free;
1754 /* Root dentry doesn't have .d_revalidate */
1755 sb->s_d_op = &fuse_dentry_operations;
1756
1757 mutex_lock(&fuse_mutex);
1758 err = -EINVAL;
1759 if (ctx->fudptr && *ctx->fudptr)
1760 goto err_unlock;
1761
1762 err = fuse_ctl_add_conn(fc);
1763 if (err)
1764 goto err_unlock;
1765
1766 list_add_tail(&fc->entry, &fuse_conn_list);
1767 sb->s_root = root_dentry;
1768 if (ctx->fudptr)
1769 *ctx->fudptr = fud;
1770 mutex_unlock(&fuse_mutex);
1771 return 0;
1772
1773 err_unlock:
1774 mutex_unlock(&fuse_mutex);
1775 dput(root_dentry);
1776 err_dev_free:
1777 if (fud)
1778 fuse_dev_free(fud);
1779 err_free_dax:
1780 if (IS_ENABLED(CONFIG_FUSE_DAX))
1781 fuse_dax_conn_free(fc);
1782 err:
1783 return err;
1784 }
1785 EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1786
1787 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1788 {
1789 struct fuse_fs_context *ctx = fsc->fs_private;
1790 int err;
1791
1792 if (!ctx->file || !ctx->rootmode_present ||
1793 !ctx->user_id_present || !ctx->group_id_present)
1794 return -EINVAL;
1795
1796 /*
1797 * Require mount to happen from the same user namespace which
1798 * opened /dev/fuse to prevent potential attacks.
1799 */
1800 if ((ctx->file->f_op != &fuse_dev_operations) ||
1801 (ctx->file->f_cred->user_ns != sb->s_user_ns))
1802 return -EINVAL;
1803 ctx->fudptr = &ctx->file->private_data;
1804
1805 err = fuse_fill_super_common(sb, ctx);
1806 if (err)
1807 return err;
1808 /* file->private_data shall be visible on all CPUs after this */
1809 smp_mb();
1810 fuse_send_init(get_fuse_mount_super(sb));
1811 return 0;
1812 }
1813
1814 /*
1815 * This is the path where user supplied an already initialized fuse dev. In
1816 * this case never create a new super if the old one is gone.
1817 */
1818 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
1819 {
1820 return -ENOTCONN;
1821 }
1822
1823 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
1824 {
1825
1826 return fsc->sget_key == get_fuse_conn_super(sb);
1827 }
1828
1829 static int fuse_get_tree(struct fs_context *fsc)
1830 {
1831 struct fuse_fs_context *ctx = fsc->fs_private;
1832 struct fuse_dev *fud;
1833 struct fuse_conn *fc;
1834 struct fuse_mount *fm;
1835 struct super_block *sb;
1836 int err;
1837
1838 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1839 if (!fc)
1840 return -ENOMEM;
1841
1842 fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1843 if (!fm) {
1844 kfree(fc);
1845 return -ENOMEM;
1846 }
1847
1848 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
1849 fc->release = fuse_free_conn;
1850
1851 fsc->s_fs_info = fm;
1852
1853 if (ctx->fd_present)
1854 ctx->file = fget(ctx->fd);
1855
1856 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
1857 err = get_tree_bdev(fsc, fuse_fill_super);
1858 goto out;
1859 }
1860 /*
1861 * While block dev mount can be initialized with a dummy device fd
1862 * (found by device name), normal fuse mounts can't
1863 */
1864 err = -EINVAL;
1865 if (!ctx->file)
1866 goto out;
1867
1868 /*
1869 * Allow creating a fuse mount with an already initialized fuse
1870 * connection
1871 */
1872 fud = READ_ONCE(ctx->file->private_data);
1873 if (ctx->file->f_op == &fuse_dev_operations && fud) {
1874 fsc->sget_key = fud->fc;
1875 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
1876 err = PTR_ERR_OR_ZERO(sb);
1877 if (!IS_ERR(sb))
1878 fsc->root = dget(sb->s_root);
1879 } else {
1880 err = get_tree_nodev(fsc, fuse_fill_super);
1881 }
1882 out:
1883 if (fsc->s_fs_info)
1884 fuse_mount_destroy(fm);
1885 if (ctx->file)
1886 fput(ctx->file);
1887 return err;
1888 }
1889
1890 static const struct fs_context_operations fuse_context_ops = {
1891 .free = fuse_free_fsc,
1892 .parse_param = fuse_parse_param,
1893 .reconfigure = fuse_reconfigure,
1894 .get_tree = fuse_get_tree,
1895 };
1896
1897 /*
1898 * Set up the filesystem mount context.
1899 */
1900 static int fuse_init_fs_context(struct fs_context *fsc)
1901 {
1902 struct fuse_fs_context *ctx;
1903
1904 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1905 if (!ctx)
1906 return -ENOMEM;
1907
1908 ctx->max_read = ~0;
1909 ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1910 ctx->legacy_opts_show = true;
1911
1912 #ifdef CONFIG_BLOCK
1913 if (fsc->fs_type == &fuseblk_fs_type) {
1914 ctx->is_bdev = true;
1915 ctx->destroy = true;
1916 }
1917 #endif
1918
1919 fsc->fs_private = ctx;
1920 fsc->ops = &fuse_context_ops;
1921 return 0;
1922 }
1923
1924 bool fuse_mount_remove(struct fuse_mount *fm)
1925 {
1926 struct fuse_conn *fc = fm->fc;
1927 bool last = false;
1928
1929 down_write(&fc->killsb);
1930 list_del_init(&fm->fc_entry);
1931 if (list_empty(&fc->mounts))
1932 last = true;
1933 up_write(&fc->killsb);
1934
1935 return last;
1936 }
1937 EXPORT_SYMBOL_GPL(fuse_mount_remove);
1938
1939 void fuse_conn_destroy(struct fuse_mount *fm)
1940 {
1941 struct fuse_conn *fc = fm->fc;
1942
1943 if (fc->destroy)
1944 fuse_send_destroy(fm);
1945
1946 fuse_abort_conn(fc);
1947 fuse_wait_aborted(fc);
1948
1949 if (!list_empty(&fc->entry)) {
1950 mutex_lock(&fuse_mutex);
1951 list_del(&fc->entry);
1952 fuse_ctl_remove_conn(fc);
1953 mutex_unlock(&fuse_mutex);
1954 }
1955 }
1956 EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1957
1958 static void fuse_sb_destroy(struct super_block *sb)
1959 {
1960 struct fuse_mount *fm = get_fuse_mount_super(sb);
1961 bool last;
1962
1963 if (sb->s_root) {
1964 last = fuse_mount_remove(fm);
1965 if (last)
1966 fuse_conn_destroy(fm);
1967 }
1968 }
1969
1970 void fuse_mount_destroy(struct fuse_mount *fm)
1971 {
1972 fuse_conn_put(fm->fc);
1973 kfree_rcu(fm, rcu);
1974 }
1975 EXPORT_SYMBOL(fuse_mount_destroy);
1976
1977 static void fuse_kill_sb_anon(struct super_block *sb)
1978 {
1979 fuse_sb_destroy(sb);
1980 kill_anon_super(sb);
1981 fuse_mount_destroy(get_fuse_mount_super(sb));
1982 }
1983
1984 static struct file_system_type fuse_fs_type = {
1985 .owner = THIS_MODULE,
1986 .name = "fuse",
1987 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1988 .init_fs_context = fuse_init_fs_context,
1989 .parameters = fuse_fs_parameters,
1990 .kill_sb = fuse_kill_sb_anon,
1991 };
1992 MODULE_ALIAS_FS("fuse");
1993
1994 #ifdef CONFIG_BLOCK
1995 static void fuse_kill_sb_blk(struct super_block *sb)
1996 {
1997 fuse_sb_destroy(sb);
1998 kill_block_super(sb);
1999 fuse_mount_destroy(get_fuse_mount_super(sb));
2000 }
2001
2002 static struct file_system_type fuseblk_fs_type = {
2003 .owner = THIS_MODULE,
2004 .name = "fuseblk",
2005 .init_fs_context = fuse_init_fs_context,
2006 .parameters = fuse_fs_parameters,
2007 .kill_sb = fuse_kill_sb_blk,
2008 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
2009 };
2010 MODULE_ALIAS_FS("fuseblk");
2011
2012 static inline int register_fuseblk(void)
2013 {
2014 return register_filesystem(&fuseblk_fs_type);
2015 }
2016
2017 static inline void unregister_fuseblk(void)
2018 {
2019 unregister_filesystem(&fuseblk_fs_type);
2020 }
2021 #else
2022 static inline int register_fuseblk(void)
2023 {
2024 return 0;
2025 }
2026
2027 static inline void unregister_fuseblk(void)
2028 {
2029 }
2030 #endif
2031
2032 static void fuse_inode_init_once(void *foo)
2033 {
2034 struct inode *inode = foo;
2035
2036 inode_init_once(inode);
2037 }
2038
2039 static int __init fuse_fs_init(void)
2040 {
2041 int err;
2042
2043 fuse_inode_cachep = kmem_cache_create("fuse_inode",
2044 sizeof(struct fuse_inode), 0,
2045 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
2046 fuse_inode_init_once);
2047 err = -ENOMEM;
2048 if (!fuse_inode_cachep)
2049 goto out;
2050
2051 err = register_fuseblk();
2052 if (err)
2053 goto out2;
2054
2055 err = register_filesystem(&fuse_fs_type);
2056 if (err)
2057 goto out3;
2058
2059 return 0;
2060
2061 out3:
2062 unregister_fuseblk();
2063 out2:
2064 kmem_cache_destroy(fuse_inode_cachep);
2065 out:
2066 return err;
2067 }
2068
2069 static void fuse_fs_cleanup(void)
2070 {
2071 unregister_filesystem(&fuse_fs_type);
2072 unregister_fuseblk();
2073
2074 /*
2075 * Make sure all delayed rcu free inodes are flushed before we
2076 * destroy cache.
2077 */
2078 rcu_barrier();
2079 kmem_cache_destroy(fuse_inode_cachep);
2080 }
2081
2082 static struct kobject *fuse_kobj;
2083
2084 static int fuse_sysfs_init(void)
2085 {
2086 int err;
2087
2088 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
2089 if (!fuse_kobj) {
2090 err = -ENOMEM;
2091 goto out_err;
2092 }
2093
2094 err = sysfs_create_mount_point(fuse_kobj, "connections");
2095 if (err)
2096 goto out_fuse_unregister;
2097
2098 return 0;
2099
2100 out_fuse_unregister:
2101 kobject_put(fuse_kobj);
2102 out_err:
2103 return err;
2104 }
2105
2106 static void fuse_sysfs_cleanup(void)
2107 {
2108 sysfs_remove_mount_point(fuse_kobj, "connections");
2109 kobject_put(fuse_kobj);
2110 }
2111
2112 static int __init fuse_init(void)
2113 {
2114 int res;
2115
2116 pr_info("init (API version %i.%i)\n",
2117 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
2118
2119 INIT_LIST_HEAD(&fuse_conn_list);
2120 res = fuse_fs_init();
2121 if (res)
2122 goto err;
2123
2124 res = fuse_dev_init();
2125 if (res)
2126 goto err_fs_cleanup;
2127
2128 res = fuse_sysfs_init();
2129 if (res)
2130 goto err_dev_cleanup;
2131
2132 res = fuse_ctl_init();
2133 if (res)
2134 goto err_sysfs_cleanup;
2135
2136 sanitize_global_limit(&max_user_bgreq);
2137 sanitize_global_limit(&max_user_congthresh);
2138
2139 return 0;
2140
2141 err_sysfs_cleanup:
2142 fuse_sysfs_cleanup();
2143 err_dev_cleanup:
2144 fuse_dev_cleanup();
2145 err_fs_cleanup:
2146 fuse_fs_cleanup();
2147 err:
2148 return res;
2149 }
2150
2151 static void __exit fuse_exit(void)
2152 {
2153 pr_debug("exit\n");
2154
2155 fuse_ctl_cleanup();
2156 fuse_sysfs_cleanup();
2157 fuse_fs_cleanup();
2158 fuse_dev_cleanup();
2159 }
2160
2161 module_init(fuse_init);
2162 module_exit(fuse_exit);
2163
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