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Linux 6.13-rc4
[linux.git] / fs / fuse / inode.c
blob3ce4f4e81d09e867c3a7db7b1dbb819f88ed34ef
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 int fuse_max_pages_limit = 256;
39
40 unsigned max_user_bgreq;
41 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
42 &max_user_bgreq, 0644);
43 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
44 MODULE_PARM_DESC(max_user_bgreq,
45 "Global limit for the maximum number of backgrounded requests an "
46 "unprivileged user can set");
47
48 unsigned max_user_congthresh;
49 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
50 &max_user_congthresh, 0644);
51 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
52 MODULE_PARM_DESC(max_user_congthresh,
53 "Global limit for the maximum congestion threshold an "
54 "unprivileged user can set");
55
56 #define FUSE_DEFAULT_BLKSIZE 512
57
58 /** Maximum number of outstanding background requests */
59 #define FUSE_DEFAULT_MAX_BACKGROUND 12
60
61 /** Congestion starts at 75% of maximum */
62 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
63
64 #ifdef CONFIG_BLOCK
65 static struct file_system_type fuseblk_fs_type;
66 #endif
67
68 struct fuse_forget_link *fuse_alloc_forget(void)
69 {
70 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
71 }
72
73 static struct fuse_submount_lookup *fuse_alloc_submount_lookup(void)
74 {
75 struct fuse_submount_lookup *sl;
76
77 sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT);
78 if (!sl)
79 return NULL;
80 sl->forget = fuse_alloc_forget();
81 if (!sl->forget)
82 goto out_free;
83
84 return sl;
85
86 out_free:
87 kfree(sl);
88 return NULL;
89 }
90
91 static struct inode *fuse_alloc_inode(struct super_block *sb)
92 {
93 struct fuse_inode *fi;
94
95 fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL);
96 if (!fi)
97 return NULL;
98
99 fi->i_time = 0;
100 fi->inval_mask = ~0;
101 fi->nodeid = 0;
102 fi->nlookup = 0;
103 fi->attr_version = 0;
104 fi->orig_ino = 0;
105 fi->state = 0;
106 fi->submount_lookup = NULL;
107 mutex_init(&fi->mutex);
108 spin_lock_init(&fi->lock);
109 fi->forget = fuse_alloc_forget();
110 if (!fi->forget)
111 goto out_free;
112
113 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
114 goto out_free_forget;
115
116 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
117 fuse_inode_backing_set(fi, NULL);
118
119 return &fi->inode;
120
121 out_free_forget:
122 kfree(fi->forget);
123 out_free:
124 kmem_cache_free(fuse_inode_cachep, fi);
125 return NULL;
126 }
127
128 static void fuse_free_inode(struct inode *inode)
129 {
130 struct fuse_inode *fi = get_fuse_inode(inode);
131
132 mutex_destroy(&fi->mutex);
133 kfree(fi->forget);
134 #ifdef CONFIG_FUSE_DAX
135 kfree(fi->dax);
136 #endif
137 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
138 fuse_backing_put(fuse_inode_backing(fi));
139
140 kmem_cache_free(fuse_inode_cachep, fi);
141 }
142
143 static void fuse_cleanup_submount_lookup(struct fuse_conn *fc,
144 struct fuse_submount_lookup *sl)
145 {
146 if (!refcount_dec_and_test(&sl->count))
147 return;
148
149 fuse_queue_forget(fc, sl->forget, sl->nodeid, 1);
150 sl->forget = NULL;
151 kfree(sl);
152 }
153
154 static void fuse_evict_inode(struct inode *inode)
155 {
156 struct fuse_inode *fi = get_fuse_inode(inode);
157
158 /* Will write inode on close/munmap and in all other dirtiers */
159 WARN_ON(inode->i_state & I_DIRTY_INODE);
160
161 truncate_inode_pages_final(&inode->i_data);
162 clear_inode(inode);
163 if (inode->i_sb->s_flags & SB_ACTIVE) {
164 struct fuse_conn *fc = get_fuse_conn(inode);
165
166 if (FUSE_IS_DAX(inode))
167 fuse_dax_inode_cleanup(inode);
168 if (fi->nlookup) {
169 fuse_queue_forget(fc, fi->forget, fi->nodeid,
170 fi->nlookup);
171 fi->forget = NULL;
172 }
173
174 if (fi->submount_lookup) {
175 fuse_cleanup_submount_lookup(fc, fi->submount_lookup);
176 fi->submount_lookup = NULL;
177 }
178 /*
179 * Evict of non-deleted inode may race with outstanding
180 * LOOKUP/READDIRPLUS requests and result in inconsistency when
181 * the request finishes. Deal with that here by bumping a
182 * counter that can be compared to the starting value.
183 */
184 if (inode->i_nlink > 0)
185 atomic64_inc(&fc->evict_ctr);
186 }
187 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
188 WARN_ON(fi->iocachectr != 0);
189 WARN_ON(!list_empty(&fi->write_files));
190 WARN_ON(!list_empty(&fi->queued_writes));
191 }
192 }
193
194 static int fuse_reconfigure(struct fs_context *fsc)
195 {
196 struct super_block *sb = fsc->root->d_sb;
197
198 sync_filesystem(sb);
199 if (fsc->sb_flags & SB_MANDLOCK)
200 return -EINVAL;
201
202 return 0;
203 }
204
205 /*
206 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
207 * so that it will fit.
208 */
209 static ino_t fuse_squash_ino(u64 ino64)
210 {
211 ino_t ino = (ino_t) ino64;
212 if (sizeof(ino_t) < sizeof(u64))
213 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
214 return ino;
215 }
216
217 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
218 struct fuse_statx *sx,
219 u64 attr_valid, u32 cache_mask,
220 u64 evict_ctr)
221 {
222 struct fuse_conn *fc = get_fuse_conn(inode);
223 struct fuse_inode *fi = get_fuse_inode(inode);
224
225 lockdep_assert_held(&fi->lock);
226
227 /*
228 * Clear basic stats from invalid mask.
229 *
230 * Don't do this if this is coming from a fuse_iget() call and there
231 * might have been a racing evict which would've invalidated the result
232 * if the attr_version would've been preserved.
233 *
234 * !evict_ctr -> this is create
235 * fi->attr_version != 0 -> this is not a new inode
236 * evict_ctr == fuse_get_evict_ctr() -> no evicts while during request
237 */
238 if (!evict_ctr || fi->attr_version || evict_ctr == fuse_get_evict_ctr(fc))
239 set_mask_bits(&fi->inval_mask, STATX_BASIC_STATS, 0);
240
241 fi->attr_version = atomic64_inc_return(&fc->attr_version);
242 fi->i_time = attr_valid;
243
244 inode->i_ino = fuse_squash_ino(attr->ino);
245 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
246 set_nlink(inode, attr->nlink);
247 inode->i_uid = make_kuid(fc->user_ns, attr->uid);
248 inode->i_gid = make_kgid(fc->user_ns, attr->gid);
249 inode->i_blocks = attr->blocks;
250
251 /* Sanitize nsecs */
252 attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1);
253 attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1);
254 attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1);
255
256 inode_set_atime(inode, attr->atime, attr->atimensec);
257 /* mtime from server may be stale due to local buffered write */
258 if (!(cache_mask & STATX_MTIME)) {
259 inode_set_mtime(inode, attr->mtime, attr->mtimensec);
260 }
261 if (!(cache_mask & STATX_CTIME)) {
262 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
263 }
264 if (sx) {
265 /* Sanitize nsecs */
266 sx->btime.tv_nsec =
267 min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1);
268
269 /*
270 * Btime has been queried, cache is valid (whether or not btime
271 * is available or not) so clear STATX_BTIME from inval_mask.
272 *
273 * Availability of the btime attribute is indicated in
274 * FUSE_I_BTIME
275 */
276 set_mask_bits(&fi->inval_mask, STATX_BTIME, 0);
277 if (sx->mask & STATX_BTIME) {
278 set_bit(FUSE_I_BTIME, &fi->state);
279 fi->i_btime.tv_sec = sx->btime.tv_sec;
280 fi->i_btime.tv_nsec = sx->btime.tv_nsec;
281 }
282 }
283
284 if (attr->blksize != 0)
285 inode->i_blkbits = ilog2(attr->blksize);
286 else
287 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
288
289 /*
290 * Don't set the sticky bit in i_mode, unless we want the VFS
291 * to check permissions. This prevents failures due to the
292 * check in may_delete().
293 */
294 fi->orig_i_mode = inode->i_mode;
295 if (!fc->default_permissions)
296 inode->i_mode &= ~S_ISVTX;
297
298 fi->orig_ino = attr->ino;
299
300 /*
301 * We are refreshing inode data and it is possible that another
302 * client set suid/sgid or security.capability xattr. So clear
303 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
304 * was set or if security.capability xattr was set. But we don't
305 * know if security.capability has been set or not. So clear it
306 * anyway. Its less efficient but should be safe.
307 */
308 inode->i_flags &= ~S_NOSEC;
309 }
310
311 u32 fuse_get_cache_mask(struct inode *inode)
312 {
313 struct fuse_conn *fc = get_fuse_conn(inode);
314
315 if (!fc->writeback_cache || !S_ISREG(inode->i_mode))
316 return 0;
317
318 return STATX_MTIME | STATX_CTIME | STATX_SIZE;
319 }
320
321 static void fuse_change_attributes_i(struct inode *inode, struct fuse_attr *attr,
322 struct fuse_statx *sx, u64 attr_valid,
323 u64 attr_version, u64 evict_ctr)
324 {
325 struct fuse_conn *fc = get_fuse_conn(inode);
326 struct fuse_inode *fi = get_fuse_inode(inode);
327 u32 cache_mask;
328 loff_t oldsize;
329 struct timespec64 old_mtime;
330
331 spin_lock(&fi->lock);
332 /*
333 * In case of writeback_cache enabled, writes update mtime, ctime and
334 * may update i_size. In these cases trust the cached value in the
335 * inode.
336 */
337 cache_mask = fuse_get_cache_mask(inode);
338 if (cache_mask & STATX_SIZE)
339 attr->size = i_size_read(inode);
340
341 if (cache_mask & STATX_MTIME) {
342 attr->mtime = inode_get_mtime_sec(inode);
343 attr->mtimensec = inode_get_mtime_nsec(inode);
344 }
345 if (cache_mask & STATX_CTIME) {
346 attr->ctime = inode_get_ctime_sec(inode);
347 attr->ctimensec = inode_get_ctime_nsec(inode);
348 }
349
350 if ((attr_version != 0 && fi->attr_version > attr_version) ||
351 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
352 spin_unlock(&fi->lock);
353 return;
354 }
355
356 old_mtime = inode_get_mtime(inode);
357 fuse_change_attributes_common(inode, attr, sx, attr_valid, cache_mask,
358 evict_ctr);
359
360 oldsize = inode->i_size;
361 /*
362 * In case of writeback_cache enabled, the cached writes beyond EOF
363 * extend local i_size without keeping userspace server in sync. So,
364 * attr->size coming from server can be stale. We cannot trust it.
365 */
366 if (!(cache_mask & STATX_SIZE))
367 i_size_write(inode, attr->size);
368 spin_unlock(&fi->lock);
369
370 if (!cache_mask && S_ISREG(inode->i_mode)) {
371 bool inval = false;
372
373 if (oldsize != attr->size) {
374 truncate_pagecache(inode, attr->size);
375 if (!fc->explicit_inval_data)
376 inval = true;
377 } else if (fc->auto_inval_data) {
378 struct timespec64 new_mtime = {
379 .tv_sec = attr->mtime,
380 .tv_nsec = attr->mtimensec,
381 };
382
383 /*
384 * Auto inval mode also checks and invalidates if mtime
385 * has changed.
386 */
387 if (!timespec64_equal(&old_mtime, &new_mtime))
388 inval = true;
389 }
390
391 if (inval)
392 invalidate_inode_pages2(inode->i_mapping);
393 }
394
395 if (IS_ENABLED(CONFIG_FUSE_DAX))
396 fuse_dax_dontcache(inode, attr->flags);
397 }
398
399 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
400 struct fuse_statx *sx, u64 attr_valid,
401 u64 attr_version)
402 {
403 fuse_change_attributes_i(inode, attr, sx, attr_valid, attr_version, 0);
404 }
405
406 static void fuse_init_submount_lookup(struct fuse_submount_lookup *sl,
407 u64 nodeid)
408 {
409 sl->nodeid = nodeid;
410 refcount_set(&sl->count, 1);
411 }
412
413 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr,
414 struct fuse_conn *fc)
415 {
416 inode->i_mode = attr->mode & S_IFMT;
417 inode->i_size = attr->size;
418 inode_set_mtime(inode, attr->mtime, attr->mtimensec);
419 inode_set_ctime(inode, attr->ctime, attr->ctimensec);
420 if (S_ISREG(inode->i_mode)) {
421 fuse_init_common(inode);
422 fuse_init_file_inode(inode, attr->flags);
423 } else if (S_ISDIR(inode->i_mode))
424 fuse_init_dir(inode);
425 else if (S_ISLNK(inode->i_mode))
426 fuse_init_symlink(inode);
427 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
428 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
429 fuse_init_common(inode);
430 init_special_inode(inode, inode->i_mode,
431 new_decode_dev(attr->rdev));
432 } else
433 BUG();
434 /*
435 * Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL
436 * so they see the exact same behavior as before.
437 */
438 if (!fc->posix_acl)
439 inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE;
440 }
441
442 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
443 {
444 u64 nodeid = *(u64 *) _nodeidp;
445 if (get_node_id(inode) == nodeid)
446 return 1;
447 else
448 return 0;
449 }
450
451 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
452 {
453 u64 nodeid = *(u64 *) _nodeidp;
454 get_fuse_inode(inode)->nodeid = nodeid;
455 return 0;
456 }
457
458 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
459 int generation, struct fuse_attr *attr,
460 u64 attr_valid, u64 attr_version,
461 u64 evict_ctr)
462 {
463 struct inode *inode;
464 struct fuse_inode *fi;
465 struct fuse_conn *fc = get_fuse_conn_super(sb);
466
467 /*
468 * Auto mount points get their node id from the submount root, which is
469 * not a unique identifier within this filesystem.
470 *
471 * To avoid conflicts, do not place submount points into the inode hash
472 * table.
473 */
474 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
475 S_ISDIR(attr->mode)) {
476 struct fuse_inode *fi;
477
478 inode = new_inode(sb);
479 if (!inode)
480 return NULL;
481
482 fuse_init_inode(inode, attr, fc);
483 fi = get_fuse_inode(inode);
484 fi->nodeid = nodeid;
485 fi->submount_lookup = fuse_alloc_submount_lookup();
486 if (!fi->submount_lookup) {
487 iput(inode);
488 return NULL;
489 }
490 /* Sets nlookup = 1 on fi->submount_lookup->nlookup */
491 fuse_init_submount_lookup(fi->submount_lookup, nodeid);
492 inode->i_flags |= S_AUTOMOUNT;
493 goto done;
494 }
495
496 retry:
497 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
498 if (!inode)
499 return NULL;
500
501 if ((inode->i_state & I_NEW)) {
502 inode->i_flags |= S_NOATIME;
503 if (!fc->writeback_cache || !S_ISREG(attr->mode))
504 inode->i_flags |= S_NOCMTIME;
505 inode->i_generation = generation;
506 fuse_init_inode(inode, attr, fc);
507 unlock_new_inode(inode);
508 } else if (fuse_stale_inode(inode, generation, attr)) {
509 /* nodeid was reused, any I/O on the old inode should fail */
510 fuse_make_bad(inode);
511 if (inode != d_inode(sb->s_root)) {
512 remove_inode_hash(inode);
513 iput(inode);
514 goto retry;
515 }
516 }
517 fi = get_fuse_inode(inode);
518 spin_lock(&fi->lock);
519 fi->nlookup++;
520 spin_unlock(&fi->lock);
521 done:
522 fuse_change_attributes_i(inode, attr, NULL, attr_valid, attr_version,
523 evict_ctr);
524 return inode;
525 }
526
527 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
528 struct fuse_mount **fm)
529 {
530 struct fuse_mount *fm_iter;
531 struct inode *inode;
532
533 WARN_ON(!rwsem_is_locked(&fc->killsb));
534 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
535 if (!fm_iter->sb)
536 continue;
537
538 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
539 if (inode) {
540 if (fm)
541 *fm = fm_iter;
542 return inode;
543 }
544 }
545
546 return NULL;
547 }
548
549 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
550 loff_t offset, loff_t len)
551 {
552 struct fuse_inode *fi;
553 struct inode *inode;
554 pgoff_t pg_start;
555 pgoff_t pg_end;
556
557 inode = fuse_ilookup(fc, nodeid, NULL);
558 if (!inode)
559 return -ENOENT;
560
561 fi = get_fuse_inode(inode);
562 spin_lock(&fi->lock);
563 fi->attr_version = atomic64_inc_return(&fc->attr_version);
564 spin_unlock(&fi->lock);
565
566 fuse_invalidate_attr(inode);
567 forget_all_cached_acls(inode);
568 if (offset >= 0) {
569 pg_start = offset >> PAGE_SHIFT;
570 if (len <= 0)
571 pg_end = -1;
572 else
573 pg_end = (offset + len - 1) >> PAGE_SHIFT;
574 invalidate_inode_pages2_range(inode->i_mapping,
575 pg_start, pg_end);
576 }
577 iput(inode);
578 return 0;
579 }
580
581 bool fuse_lock_inode(struct inode *inode)
582 {
583 bool locked = false;
584
585 if (!get_fuse_conn(inode)->parallel_dirops) {
586 mutex_lock(&get_fuse_inode(inode)->mutex);
587 locked = true;
588 }
589
590 return locked;
591 }
592
593 void fuse_unlock_inode(struct inode *inode, bool locked)
594 {
595 if (locked)
596 mutex_unlock(&get_fuse_inode(inode)->mutex);
597 }
598
599 static void fuse_umount_begin(struct super_block *sb)
600 {
601 struct fuse_conn *fc = get_fuse_conn_super(sb);
602
603 if (fc->no_force_umount)
604 return;
605
606 fuse_abort_conn(fc);
607
608 // Only retire block-device-based superblocks.
609 if (sb->s_bdev != NULL)
610 retire_super(sb);
611 }
612
613 static void fuse_send_destroy(struct fuse_mount *fm)
614 {
615 if (fm->fc->conn_init) {
616 FUSE_ARGS(args);
617
618 args.opcode = FUSE_DESTROY;
619 args.force = true;
620 args.nocreds = true;
621 fuse_simple_request(fm, &args);
622 }
623 }
624
625 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
626 {
627 stbuf->f_type = FUSE_SUPER_MAGIC;
628 stbuf->f_bsize = attr->bsize;
629 stbuf->f_frsize = attr->frsize;
630 stbuf->f_blocks = attr->blocks;
631 stbuf->f_bfree = attr->bfree;
632 stbuf->f_bavail = attr->bavail;
633 stbuf->f_files = attr->files;
634 stbuf->f_ffree = attr->ffree;
635 stbuf->f_namelen = attr->namelen;
636 /* fsid is left zero */
637 }
638
639 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
640 {
641 struct super_block *sb = dentry->d_sb;
642 struct fuse_mount *fm = get_fuse_mount_super(sb);
643 FUSE_ARGS(args);
644 struct fuse_statfs_out outarg;
645 int err;
646
647 if (!fuse_allow_current_process(fm->fc)) {
648 buf->f_type = FUSE_SUPER_MAGIC;
649 return 0;
650 }
651
652 memset(&outarg, 0, sizeof(outarg));
653 args.in_numargs = 0;
654 args.opcode = FUSE_STATFS;
655 args.nodeid = get_node_id(d_inode(dentry));
656 args.out_numargs = 1;
657 args.out_args[0].size = sizeof(outarg);
658 args.out_args[0].value = &outarg;
659 err = fuse_simple_request(fm, &args);
660 if (!err)
661 convert_fuse_statfs(buf, &outarg.st);
662 return err;
663 }
664
665 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void)
666 {
667 struct fuse_sync_bucket *bucket;
668
669 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL);
670 if (bucket) {
671 init_waitqueue_head(&bucket->waitq);
672 /* Initial active count */
673 atomic_set(&bucket->count, 1);
674 }
675 return bucket;
676 }
677
678 static void fuse_sync_fs_writes(struct fuse_conn *fc)
679 {
680 struct fuse_sync_bucket *bucket, *new_bucket;
681 int count;
682
683 new_bucket = fuse_sync_bucket_alloc();
684 spin_lock(&fc->lock);
685 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
686 count = atomic_read(&bucket->count);
687 WARN_ON(count < 1);
688 /* No outstanding writes? */
689 if (count == 1) {
690 spin_unlock(&fc->lock);
691 kfree(new_bucket);
692 return;
693 }
694
695 /*
696 * Completion of new bucket depends on completion of this bucket, so add
697 * one more count.
698 */
699 atomic_inc(&new_bucket->count);
700 rcu_assign_pointer(fc->curr_bucket, new_bucket);
701 spin_unlock(&fc->lock);
702 /*
703 * Drop initial active count. At this point if all writes in this and
704 * ancestor buckets complete, the count will go to zero and this task
705 * will be woken up.
706 */
707 atomic_dec(&bucket->count);
708
709 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0);
710
711 /* Drop temp count on descendant bucket */
712 fuse_sync_bucket_dec(new_bucket);
713 kfree_rcu(bucket, rcu);
714 }
715
716 static int fuse_sync_fs(struct super_block *sb, int wait)
717 {
718 struct fuse_mount *fm = get_fuse_mount_super(sb);
719 struct fuse_conn *fc = fm->fc;
720 struct fuse_syncfs_in inarg;
721 FUSE_ARGS(args);
722 int err;
723
724 /*
725 * Userspace cannot handle the wait == 0 case. Avoid a
726 * gratuitous roundtrip.
727 */
728 if (!wait)
729 return 0;
730
731 /* The filesystem is being unmounted. Nothing to do. */
732 if (!sb->s_root)
733 return 0;
734
735 if (!fc->sync_fs)
736 return 0;
737
738 fuse_sync_fs_writes(fc);
739
740 memset(&inarg, 0, sizeof(inarg));
741 args.in_numargs = 1;
742 args.in_args[0].size = sizeof(inarg);
743 args.in_args[0].value = &inarg;
744 args.opcode = FUSE_SYNCFS;
745 args.nodeid = get_node_id(sb->s_root->d_inode);
746 args.out_numargs = 0;
747
748 err = fuse_simple_request(fm, &args);
749 if (err == -ENOSYS) {
750 fc->sync_fs = 0;
751 err = 0;
752 }
753
754 return err;
755 }
756
757 enum {
758 OPT_SOURCE,
759 OPT_SUBTYPE,
760 OPT_FD,
761 OPT_ROOTMODE,
762 OPT_USER_ID,
763 OPT_GROUP_ID,
764 OPT_DEFAULT_PERMISSIONS,
765 OPT_ALLOW_OTHER,
766 OPT_MAX_READ,
767 OPT_BLKSIZE,
768 OPT_ERR
769 };
770
771 static const struct fs_parameter_spec fuse_fs_parameters[] = {
772 fsparam_string ("source", OPT_SOURCE),
773 fsparam_u32 ("fd", OPT_FD),
774 fsparam_u32oct ("rootmode", OPT_ROOTMODE),
775 fsparam_uid ("user_id", OPT_USER_ID),
776 fsparam_gid ("group_id", OPT_GROUP_ID),
777 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
778 fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
779 fsparam_u32 ("max_read", OPT_MAX_READ),
780 fsparam_u32 ("blksize", OPT_BLKSIZE),
781 fsparam_string ("subtype", OPT_SUBTYPE),
782 {}
783 };
784
785 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param)
786 {
787 struct fs_parse_result result;
788 struct fuse_fs_context *ctx = fsc->fs_private;
789 int opt;
790 kuid_t kuid;
791 kgid_t kgid;
792
793 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
794 /*
795 * Ignore options coming from mount(MS_REMOUNT) for backward
796 * compatibility.
797 */
798 if (fsc->oldapi)
799 return 0;
800
801 return invalfc(fsc, "No changes allowed in reconfigure");
802 }
803
804 opt = fs_parse(fsc, fuse_fs_parameters, param, &result);
805 if (opt < 0)
806 return opt;
807
808 switch (opt) {
809 case OPT_SOURCE:
810 if (fsc->source)
811 return invalfc(fsc, "Multiple sources specified");
812 fsc->source = param->string;
813 param->string = NULL;
814 break;
815
816 case OPT_SUBTYPE:
817 if (ctx->subtype)
818 return invalfc(fsc, "Multiple subtypes specified");
819 ctx->subtype = param->string;
820 param->string = NULL;
821 return 0;
822
823 case OPT_FD:
824 ctx->fd = result.uint_32;
825 ctx->fd_present = true;
826 break;
827
828 case OPT_ROOTMODE:
829 if (!fuse_valid_type(result.uint_32))
830 return invalfc(fsc, "Invalid rootmode");
831 ctx->rootmode = result.uint_32;
832 ctx->rootmode_present = true;
833 break;
834
835 case OPT_USER_ID:
836 kuid = result.uid;
837 /*
838 * The requested uid must be representable in the
839 * filesystem's idmapping.
840 */
841 if (!kuid_has_mapping(fsc->user_ns, kuid))
842 return invalfc(fsc, "Invalid user_id");
843 ctx->user_id = kuid;
844 ctx->user_id_present = true;
845 break;
846
847 case OPT_GROUP_ID:
848 kgid = result.gid;
849 /*
850 * The requested gid must be representable in the
851 * filesystem's idmapping.
852 */
853 if (!kgid_has_mapping(fsc->user_ns, kgid))
854 return invalfc(fsc, "Invalid group_id");
855 ctx->group_id = kgid;
856 ctx->group_id_present = true;
857 break;
858
859 case OPT_DEFAULT_PERMISSIONS:
860 ctx->default_permissions = true;
861 break;
862
863 case OPT_ALLOW_OTHER:
864 ctx->allow_other = true;
865 break;
866
867 case OPT_MAX_READ:
868 ctx->max_read = result.uint_32;
869 break;
870
871 case OPT_BLKSIZE:
872 if (!ctx->is_bdev)
873 return invalfc(fsc, "blksize only supported for fuseblk");
874 ctx->blksize = result.uint_32;
875 break;
876
877 default:
878 return -EINVAL;
879 }
880
881 return 0;
882 }
883
884 static void fuse_free_fsc(struct fs_context *fsc)
885 {
886 struct fuse_fs_context *ctx = fsc->fs_private;
887
888 if (ctx) {
889 kfree(ctx->subtype);
890 kfree(ctx);
891 }
892 }
893
894 static int fuse_show_options(struct seq_file *m, struct dentry *root)
895 {
896 struct super_block *sb = root->d_sb;
897 struct fuse_conn *fc = get_fuse_conn_super(sb);
898
899 if (fc->legacy_opts_show) {
900 seq_printf(m, ",user_id=%u",
901 from_kuid_munged(fc->user_ns, fc->user_id));
902 seq_printf(m, ",group_id=%u",
903 from_kgid_munged(fc->user_ns, fc->group_id));
904 if (fc->default_permissions)
905 seq_puts(m, ",default_permissions");
906 if (fc->allow_other)
907 seq_puts(m, ",allow_other");
908 if (fc->max_read != ~0)
909 seq_printf(m, ",max_read=%u", fc->max_read);
910 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
911 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
912 }
913 #ifdef CONFIG_FUSE_DAX
914 if (fc->dax_mode == FUSE_DAX_ALWAYS)
915 seq_puts(m, ",dax=always");
916 else if (fc->dax_mode == FUSE_DAX_NEVER)
917 seq_puts(m, ",dax=never");
918 else if (fc->dax_mode == FUSE_DAX_INODE_USER)
919 seq_puts(m, ",dax=inode");
920 #endif
921
922 return 0;
923 }
924
925 static void fuse_iqueue_init(struct fuse_iqueue *fiq,
926 const struct fuse_iqueue_ops *ops,
927 void *priv)
928 {
929 memset(fiq, 0, sizeof(struct fuse_iqueue));
930 spin_lock_init(&fiq->lock);
931 init_waitqueue_head(&fiq->waitq);
932 INIT_LIST_HEAD(&fiq->pending);
933 INIT_LIST_HEAD(&fiq->interrupts);
934 fiq->forget_list_tail = &fiq->forget_list_head;
935 fiq->connected = 1;
936 fiq->ops = ops;
937 fiq->priv = priv;
938 }
939
940 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
941 {
942 unsigned int i;
943
944 spin_lock_init(&fpq->lock);
945 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
946 INIT_LIST_HEAD(&fpq->processing[i]);
947 INIT_LIST_HEAD(&fpq->io);
948 fpq->connected = 1;
949 }
950
951 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
952 struct user_namespace *user_ns,
953 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
954 {
955 memset(fc, 0, sizeof(*fc));
956 spin_lock_init(&fc->lock);
957 spin_lock_init(&fc->bg_lock);
958 init_rwsem(&fc->killsb);
959 refcount_set(&fc->count, 1);
960 atomic_set(&fc->dev_count, 1);
961 init_waitqueue_head(&fc->blocked_waitq);
962 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
963 INIT_LIST_HEAD(&fc->bg_queue);
964 INIT_LIST_HEAD(&fc->entry);
965 INIT_LIST_HEAD(&fc->devices);
966 atomic_set(&fc->num_waiting, 0);
967 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
968 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
969 atomic64_set(&fc->khctr, 0);
970 fc->polled_files = RB_ROOT;
971 fc->blocked = 0;
972 fc->initialized = 0;
973 fc->connected = 1;
974 atomic64_set(&fc->attr_version, 1);
975 atomic64_set(&fc->evict_ctr, 1);
976 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
977 fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
978 fc->user_ns = get_user_ns(user_ns);
979 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
980 fc->max_pages_limit = fuse_max_pages_limit;
981
982 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
983 fuse_backing_files_init(fc);
984
985 INIT_LIST_HEAD(&fc->mounts);
986 list_add(&fm->fc_entry, &fc->mounts);
987 fm->fc = fc;
988 }
989 EXPORT_SYMBOL_GPL(fuse_conn_init);
990
991 static void delayed_release(struct rcu_head *p)
992 {
993 struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu);
994
995 put_user_ns(fc->user_ns);
996 fc->release(fc);
997 }
998
999 void fuse_conn_put(struct fuse_conn *fc)
1000 {
1001 if (refcount_dec_and_test(&fc->count)) {
1002 struct fuse_iqueue *fiq = &fc->iq;
1003 struct fuse_sync_bucket *bucket;
1004
1005 if (IS_ENABLED(CONFIG_FUSE_DAX))
1006 fuse_dax_conn_free(fc);
1007 if (fiq->ops->release)
1008 fiq->ops->release(fiq);
1009 put_pid_ns(fc->pid_ns);
1010 bucket = rcu_dereference_protected(fc->curr_bucket, 1);
1011 if (bucket) {
1012 WARN_ON(atomic_read(&bucket->count) != 1);
1013 kfree(bucket);
1014 }
1015 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
1016 fuse_backing_files_free(fc);
1017 call_rcu(&fc->rcu, delayed_release);
1018 }
1019 }
1020 EXPORT_SYMBOL_GPL(fuse_conn_put);
1021
1022 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
1023 {
1024 refcount_inc(&fc->count);
1025 return fc;
1026 }
1027 EXPORT_SYMBOL_GPL(fuse_conn_get);
1028
1029 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
1030 {
1031 struct fuse_attr attr;
1032 memset(&attr, 0, sizeof(attr));
1033
1034 attr.mode = mode;
1035 attr.ino = FUSE_ROOT_ID;
1036 attr.nlink = 1;
1037 return fuse_iget(sb, FUSE_ROOT_ID, 0, &attr, 0, 0, 0);
1038 }
1039
1040 struct fuse_inode_handle {
1041 u64 nodeid;
1042 u32 generation;
1043 };
1044
1045 static struct dentry *fuse_get_dentry(struct super_block *sb,
1046 struct fuse_inode_handle *handle)
1047 {
1048 struct fuse_conn *fc = get_fuse_conn_super(sb);
1049 struct inode *inode;
1050 struct dentry *entry;
1051 int err = -ESTALE;
1052
1053 if (handle->nodeid == 0)
1054 goto out_err;
1055
1056 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
1057 if (!inode) {
1058 struct fuse_entry_out outarg;
1059 const struct qstr name = QSTR_INIT(".", 1);
1060
1061 if (!fc->export_support)
1062 goto out_err;
1063
1064 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
1065 &inode);
1066 if (err && err != -ENOENT)
1067 goto out_err;
1068 if (err || !inode) {
1069 err = -ESTALE;
1070 goto out_err;
1071 }
1072 err = -EIO;
1073 if (get_node_id(inode) != handle->nodeid)
1074 goto out_iput;
1075 }
1076 err = -ESTALE;
1077 if (inode->i_generation != handle->generation)
1078 goto out_iput;
1079
1080 entry = d_obtain_alias(inode);
1081 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
1082 fuse_invalidate_entry_cache(entry);
1083
1084 return entry;
1085
1086 out_iput:
1087 iput(inode);
1088 out_err:
1089 return ERR_PTR(err);
1090 }
1091
1092 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
1093 struct inode *parent)
1094 {
1095 int len = parent ? 6 : 3;
1096 u64 nodeid;
1097 u32 generation;
1098
1099 if (*max_len < len) {
1100 *max_len = len;
1101 return FILEID_INVALID;
1102 }
1103
1104 nodeid = get_fuse_inode(inode)->nodeid;
1105 generation = inode->i_generation;
1106
1107 fh[0] = (u32)(nodeid >> 32);
1108 fh[1] = (u32)(nodeid & 0xffffffff);
1109 fh[2] = generation;
1110
1111 if (parent) {
1112 nodeid = get_fuse_inode(parent)->nodeid;
1113 generation = parent->i_generation;
1114
1115 fh[3] = (u32)(nodeid >> 32);
1116 fh[4] = (u32)(nodeid & 0xffffffff);
1117 fh[5] = generation;
1118 }
1119
1120 *max_len = len;
1121 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN;
1122 }
1123
1124 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
1125 struct fid *fid, int fh_len, int fh_type)
1126 {
1127 struct fuse_inode_handle handle;
1128
1129 if ((fh_type != FILEID_INO64_GEN &&
1130 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3)
1131 return NULL;
1132
1133 handle.nodeid = (u64) fid->raw[0] << 32;
1134 handle.nodeid |= (u64) fid->raw[1];
1135 handle.generation = fid->raw[2];
1136 return fuse_get_dentry(sb, &handle);
1137 }
1138
1139 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
1140 struct fid *fid, int fh_len, int fh_type)
1141 {
1142 struct fuse_inode_handle parent;
1143
1144 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6)
1145 return NULL;
1146
1147 parent.nodeid = (u64) fid->raw[3] << 32;
1148 parent.nodeid |= (u64) fid->raw[4];
1149 parent.generation = fid->raw[5];
1150 return fuse_get_dentry(sb, &parent);
1151 }
1152
1153 static struct dentry *fuse_get_parent(struct dentry *child)
1154 {
1155 struct inode *child_inode = d_inode(child);
1156 struct fuse_conn *fc = get_fuse_conn(child_inode);
1157 struct inode *inode;
1158 struct dentry *parent;
1159 struct fuse_entry_out outarg;
1160 int err;
1161
1162 if (!fc->export_support)
1163 return ERR_PTR(-ESTALE);
1164
1165 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
1166 &dotdot_name, &outarg, &inode);
1167 if (err) {
1168 if (err == -ENOENT)
1169 return ERR_PTR(-ESTALE);
1170 return ERR_PTR(err);
1171 }
1172
1173 parent = d_obtain_alias(inode);
1174 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
1175 fuse_invalidate_entry_cache(parent);
1176
1177 return parent;
1178 }
1179
1180 /* only for fid encoding; no support for file handle */
1181 static const struct export_operations fuse_export_fid_operations = {
1182 .encode_fh = fuse_encode_fh,
1183 };
1184
1185 static const struct export_operations fuse_export_operations = {
1186 .fh_to_dentry = fuse_fh_to_dentry,
1187 .fh_to_parent = fuse_fh_to_parent,
1188 .encode_fh = fuse_encode_fh,
1189 .get_parent = fuse_get_parent,
1190 };
1191
1192 static const struct super_operations fuse_super_operations = {
1193 .alloc_inode = fuse_alloc_inode,
1194 .free_inode = fuse_free_inode,
1195 .evict_inode = fuse_evict_inode,
1196 .write_inode = fuse_write_inode,
1197 .drop_inode = generic_delete_inode,
1198 .umount_begin = fuse_umount_begin,
1199 .statfs = fuse_statfs,
1200 .sync_fs = fuse_sync_fs,
1201 .show_options = fuse_show_options,
1202 };
1203
1204 static void sanitize_global_limit(unsigned *limit)
1205 {
1206 /*
1207 * The default maximum number of async requests is calculated to consume
1208 * 1/2^13 of the total memory, assuming 392 bytes per request.
1209 */
1210 if (*limit == 0)
1211 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
1212
1213 if (*limit >= 1 << 16)
1214 *limit = (1 << 16) - 1;
1215 }
1216
1217 static int set_global_limit(const char *val, const struct kernel_param *kp)
1218 {
1219 int rv;
1220
1221 rv = param_set_uint(val, kp);
1222 if (rv)
1223 return rv;
1224
1225 sanitize_global_limit((unsigned *)kp->arg);
1226
1227 return 0;
1228 }
1229
1230 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
1231 {
1232 int cap_sys_admin = capable(CAP_SYS_ADMIN);
1233
1234 if (arg->minor < 13)
1235 return;
1236
1237 sanitize_global_limit(&max_user_bgreq);
1238 sanitize_global_limit(&max_user_congthresh);
1239
1240 spin_lock(&fc->bg_lock);
1241 if (arg->max_background) {
1242 fc->max_background = arg->max_background;
1243
1244 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
1245 fc->max_background = max_user_bgreq;
1246 }
1247 if (arg->congestion_threshold) {
1248 fc->congestion_threshold = arg->congestion_threshold;
1249
1250 if (!cap_sys_admin &&
1251 fc->congestion_threshold > max_user_congthresh)
1252 fc->congestion_threshold = max_user_congthresh;
1253 }
1254 spin_unlock(&fc->bg_lock);
1255 }
1256
1257 struct fuse_init_args {
1258 struct fuse_args args;
1259 struct fuse_init_in in;
1260 struct fuse_init_out out;
1261 };
1262
1263 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
1264 int error)
1265 {
1266 struct fuse_conn *fc = fm->fc;
1267 struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
1268 struct fuse_init_out *arg = &ia->out;
1269 bool ok = true;
1270
1271 if (error || arg->major != FUSE_KERNEL_VERSION)
1272 ok = false;
1273 else {
1274 unsigned long ra_pages;
1275
1276 process_init_limits(fc, arg);
1277
1278 if (arg->minor >= 6) {
1279 u64 flags = arg->flags;
1280
1281 if (flags & FUSE_INIT_EXT)
1282 flags |= (u64) arg->flags2 << 32;
1283
1284 ra_pages = arg->max_readahead / PAGE_SIZE;
1285 if (flags & FUSE_ASYNC_READ)
1286 fc->async_read = 1;
1287 if (!(flags & FUSE_POSIX_LOCKS))
1288 fc->no_lock = 1;
1289 if (arg->minor >= 17) {
1290 if (!(flags & FUSE_FLOCK_LOCKS))
1291 fc->no_flock = 1;
1292 } else {
1293 if (!(flags & FUSE_POSIX_LOCKS))
1294 fc->no_flock = 1;
1295 }
1296 if (flags & FUSE_ATOMIC_O_TRUNC)
1297 fc->atomic_o_trunc = 1;
1298 if (arg->minor >= 9) {
1299 /* LOOKUP has dependency on proto version */
1300 if (flags & FUSE_EXPORT_SUPPORT)
1301 fc->export_support = 1;
1302 }
1303 if (flags & FUSE_BIG_WRITES)
1304 fc->big_writes = 1;
1305 if (flags & FUSE_DONT_MASK)
1306 fc->dont_mask = 1;
1307 if (flags & FUSE_AUTO_INVAL_DATA)
1308 fc->auto_inval_data = 1;
1309 else if (flags & FUSE_EXPLICIT_INVAL_DATA)
1310 fc->explicit_inval_data = 1;
1311 if (flags & FUSE_DO_READDIRPLUS) {
1312 fc->do_readdirplus = 1;
1313 if (flags & FUSE_READDIRPLUS_AUTO)
1314 fc->readdirplus_auto = 1;
1315 }
1316 if (flags & FUSE_ASYNC_DIO)
1317 fc->async_dio = 1;
1318 if (flags & FUSE_WRITEBACK_CACHE)
1319 fc->writeback_cache = 1;
1320 if (flags & FUSE_PARALLEL_DIROPS)
1321 fc->parallel_dirops = 1;
1322 if (flags & FUSE_HANDLE_KILLPRIV)
1323 fc->handle_killpriv = 1;
1324 if (arg->time_gran && arg->time_gran <= 1000000000)
1325 fm->sb->s_time_gran = arg->time_gran;
1326 if ((flags & FUSE_POSIX_ACL)) {
1327 fc->default_permissions = 1;
1328 fc->posix_acl = 1;
1329 }
1330 if (flags & FUSE_CACHE_SYMLINKS)
1331 fc->cache_symlinks = 1;
1332 if (flags & FUSE_ABORT_ERROR)
1333 fc->abort_err = 1;
1334 if (flags & FUSE_MAX_PAGES) {
1335 fc->max_pages =
1336 min_t(unsigned int, fc->max_pages_limit,
1337 max_t(unsigned int, arg->max_pages, 1));
1338 }
1339 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1340 if (flags & FUSE_MAP_ALIGNMENT &&
1341 !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1342 ok = false;
1343 }
1344 if (flags & FUSE_HAS_INODE_DAX)
1345 fc->inode_dax = 1;
1346 }
1347 if (flags & FUSE_HANDLE_KILLPRIV_V2) {
1348 fc->handle_killpriv_v2 = 1;
1349 fm->sb->s_flags |= SB_NOSEC;
1350 }
1351 if (flags & FUSE_SETXATTR_EXT)
1352 fc->setxattr_ext = 1;
1353 if (flags & FUSE_SECURITY_CTX)
1354 fc->init_security = 1;
1355 if (flags & FUSE_CREATE_SUPP_GROUP)
1356 fc->create_supp_group = 1;
1357 if (flags & FUSE_DIRECT_IO_ALLOW_MMAP)
1358 fc->direct_io_allow_mmap = 1;
1359 /*
1360 * max_stack_depth is the max stack depth of FUSE fs,
1361 * so it has to be at least 1 to support passthrough
1362 * to backing files.
1363 *
1364 * with max_stack_depth > 1, the backing files can be
1365 * on a stacked fs (e.g. overlayfs) themselves and with
1366 * max_stack_depth == 1, FUSE fs can be stacked as the
1367 * underlying fs of a stacked fs (e.g. overlayfs).
1368 *
1369 * Also don't allow the combination of FUSE_PASSTHROUGH
1370 * and FUSE_WRITEBACK_CACHE, current design doesn't handle
1371 * them together.
1372 */
1373 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) &&
1374 (flags & FUSE_PASSTHROUGH) &&
1375 arg->max_stack_depth > 0 &&
1376 arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH &&
1377 !(flags & FUSE_WRITEBACK_CACHE)) {
1378 fc->passthrough = 1;
1379 fc->max_stack_depth = arg->max_stack_depth;
1380 fm->sb->s_stack_depth = arg->max_stack_depth;
1381 }
1382 if (flags & FUSE_NO_EXPORT_SUPPORT)
1383 fm->sb->s_export_op = &fuse_export_fid_operations;
1384 if (flags & FUSE_ALLOW_IDMAP) {
1385 if (fc->default_permissions)
1386 fm->sb->s_iflags &= ~SB_I_NOIDMAP;
1387 else
1388 ok = false;
1389 }
1390 } else {
1391 ra_pages = fc->max_read / PAGE_SIZE;
1392 fc->no_lock = 1;
1393 fc->no_flock = 1;
1394 }
1395
1396 fm->sb->s_bdi->ra_pages =
1397 min(fm->sb->s_bdi->ra_pages, ra_pages);
1398 fc->minor = arg->minor;
1399 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1400 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1401 fc->conn_init = 1;
1402 }
1403 kfree(ia);
1404
1405 if (!ok) {
1406 fc->conn_init = 0;
1407 fc->conn_error = 1;
1408 }
1409
1410 fuse_set_initialized(fc);
1411 wake_up_all(&fc->blocked_waitq);
1412 }
1413
1414 void fuse_send_init(struct fuse_mount *fm)
1415 {
1416 struct fuse_init_args *ia;
1417 u64 flags;
1418
1419 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1420
1421 ia->in.major = FUSE_KERNEL_VERSION;
1422 ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1423 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1424 flags =
1425 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1426 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1427 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1428 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1429 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1430 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1431 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1432 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1433 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1434 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT |
1435 FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP |
1436 FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP |
1437 FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND | FUSE_ALLOW_IDMAP;
1438 #ifdef CONFIG_FUSE_DAX
1439 if (fm->fc->dax)
1440 flags |= FUSE_MAP_ALIGNMENT;
1441 if (fuse_is_inode_dax_mode(fm->fc->dax_mode))
1442 flags |= FUSE_HAS_INODE_DAX;
1443 #endif
1444 if (fm->fc->auto_submounts)
1445 flags |= FUSE_SUBMOUNTS;
1446 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
1447 flags |= FUSE_PASSTHROUGH;
1448
1449 ia->in.flags = flags;
1450 ia->in.flags2 = flags >> 32;
1451
1452 ia->args.opcode = FUSE_INIT;
1453 ia->args.in_numargs = 1;
1454 ia->args.in_args[0].size = sizeof(ia->in);
1455 ia->args.in_args[0].value = &ia->in;
1456 ia->args.out_numargs = 1;
1457 /* Variable length argument used for backward compatibility
1458 with interface version < 7.5. Rest of init_out is zeroed
1459 by do_get_request(), so a short reply is not a problem */
1460 ia->args.out_argvar = true;
1461 ia->args.out_args[0].size = sizeof(ia->out);
1462 ia->args.out_args[0].value = &ia->out;
1463 ia->args.force = true;
1464 ia->args.nocreds = true;
1465 ia->args.end = process_init_reply;
1466
1467 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1468 process_init_reply(fm, &ia->args, -ENOTCONN);
1469 }
1470 EXPORT_SYMBOL_GPL(fuse_send_init);
1471
1472 void fuse_free_conn(struct fuse_conn *fc)
1473 {
1474 WARN_ON(!list_empty(&fc->devices));
1475 kfree(fc);
1476 }
1477 EXPORT_SYMBOL_GPL(fuse_free_conn);
1478
1479 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1480 {
1481 int err;
1482 char *suffix = "";
1483
1484 if (sb->s_bdev) {
1485 suffix = "-fuseblk";
1486 /*
1487 * sb->s_bdi points to blkdev's bdi however we want to redirect
1488 * it to our private bdi...
1489 */
1490 bdi_put(sb->s_bdi);
1491 sb->s_bdi = &noop_backing_dev_info;
1492 }
1493 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1494 MINOR(fc->dev), suffix);
1495 if (err)
1496 return err;
1497
1498 /* fuse does it's own writeback accounting */
1499 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1500 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1501
1502 /*
1503 * For a single fuse filesystem use max 1% of dirty +
1504 * writeback threshold.
1505 *
1506 * This gives about 1M of write buffer for memory maps on a
1507 * machine with 1G and 10% dirty_ratio, which should be more
1508 * than enough.
1509 *
1510 * Privileged users can raise it by writing to
1511 *
1512 * /sys/class/bdi/<bdi>/max_ratio
1513 */
1514 bdi_set_max_ratio(sb->s_bdi, 1);
1515
1516 return 0;
1517 }
1518
1519 struct fuse_dev *fuse_dev_alloc(void)
1520 {
1521 struct fuse_dev *fud;
1522 struct list_head *pq;
1523
1524 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1525 if (!fud)
1526 return NULL;
1527
1528 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1529 if (!pq) {
1530 kfree(fud);
1531 return NULL;
1532 }
1533
1534 fud->pq.processing = pq;
1535 fuse_pqueue_init(&fud->pq);
1536
1537 return fud;
1538 }
1539 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1540
1541 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1542 {
1543 fud->fc = fuse_conn_get(fc);
1544 spin_lock(&fc->lock);
1545 list_add_tail(&fud->entry, &fc->devices);
1546 spin_unlock(&fc->lock);
1547 }
1548 EXPORT_SYMBOL_GPL(fuse_dev_install);
1549
1550 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1551 {
1552 struct fuse_dev *fud;
1553
1554 fud = fuse_dev_alloc();
1555 if (!fud)
1556 return NULL;
1557
1558 fuse_dev_install(fud, fc);
1559 return fud;
1560 }
1561 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1562
1563 void fuse_dev_free(struct fuse_dev *fud)
1564 {
1565 struct fuse_conn *fc = fud->fc;
1566
1567 if (fc) {
1568 spin_lock(&fc->lock);
1569 list_del(&fud->entry);
1570 spin_unlock(&fc->lock);
1571
1572 fuse_conn_put(fc);
1573 }
1574 kfree(fud->pq.processing);
1575 kfree(fud);
1576 }
1577 EXPORT_SYMBOL_GPL(fuse_dev_free);
1578
1579 static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1580 const struct fuse_inode *fi)
1581 {
1582 struct timespec64 atime = inode_get_atime(&fi->inode);
1583 struct timespec64 mtime = inode_get_mtime(&fi->inode);
1584 struct timespec64 ctime = inode_get_ctime(&fi->inode);
1585
1586 *attr = (struct fuse_attr){
1587 .ino = fi->inode.i_ino,
1588 .size = fi->inode.i_size,
1589 .blocks = fi->inode.i_blocks,
1590 .atime = atime.tv_sec,
1591 .mtime = mtime.tv_sec,
1592 .ctime = ctime.tv_sec,
1593 .atimensec = atime.tv_nsec,
1594 .mtimensec = mtime.tv_nsec,
1595 .ctimensec = ctime.tv_nsec,
1596 .mode = fi->inode.i_mode,
1597 .nlink = fi->inode.i_nlink,
1598 .uid = __kuid_val(fi->inode.i_uid),
1599 .gid = __kgid_val(fi->inode.i_gid),
1600 .rdev = fi->inode.i_rdev,
1601 .blksize = 1u << fi->inode.i_blkbits,
1602 };
1603 }
1604
1605 static void fuse_sb_defaults(struct super_block *sb)
1606 {
1607 sb->s_magic = FUSE_SUPER_MAGIC;
1608 sb->s_op = &fuse_super_operations;
1609 sb->s_xattr = fuse_xattr_handlers;
1610 sb->s_maxbytes = MAX_LFS_FILESIZE;
1611 sb->s_time_gran = 1;
1612 sb->s_export_op = &fuse_export_operations;
1613 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1614 sb->s_iflags |= SB_I_NOIDMAP;
1615 if (sb->s_user_ns != &init_user_ns)
1616 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1617 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1618 }
1619
1620 static int fuse_fill_super_submount(struct super_block *sb,
1621 struct fuse_inode *parent_fi)
1622 {
1623 struct fuse_mount *fm = get_fuse_mount_super(sb);
1624 struct super_block *parent_sb = parent_fi->inode.i_sb;
1625 struct fuse_attr root_attr;
1626 struct inode *root;
1627 struct fuse_submount_lookup *sl;
1628 struct fuse_inode *fi;
1629
1630 fuse_sb_defaults(sb);
1631 fm->sb = sb;
1632
1633 WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1634 sb->s_bdi = bdi_get(parent_sb->s_bdi);
1635
1636 sb->s_xattr = parent_sb->s_xattr;
1637 sb->s_export_op = parent_sb->s_export_op;
1638 sb->s_time_gran = parent_sb->s_time_gran;
1639 sb->s_blocksize = parent_sb->s_blocksize;
1640 sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1641 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1642 if (parent_sb->s_subtype && !sb->s_subtype)
1643 return -ENOMEM;
1644
1645 fuse_fill_attr_from_inode(&root_attr, parent_fi);
1646 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0,
1647 fuse_get_evict_ctr(fm->fc));
1648 /*
1649 * This inode is just a duplicate, so it is not looked up and
1650 * its nlookup should not be incremented. fuse_iget() does
1651 * that, though, so undo it here.
1652 */
1653 fi = get_fuse_inode(root);
1654 fi->nlookup--;
1655
1656 sb->s_d_op = &fuse_dentry_operations;
1657 sb->s_root = d_make_root(root);
1658 if (!sb->s_root)
1659 return -ENOMEM;
1660
1661 /*
1662 * Grab the parent's submount_lookup pointer and take a
1663 * reference on the shared nlookup from the parent. This is to
1664 * prevent the last forget for this nodeid from getting
1665 * triggered until all users have finished with it.
1666 */
1667 sl = parent_fi->submount_lookup;
1668 WARN_ON(!sl);
1669 if (sl) {
1670 refcount_inc(&sl->count);
1671 fi->submount_lookup = sl;
1672 }
1673
1674 return 0;
1675 }
1676
1677 /* Filesystem context private data holds the FUSE inode of the mount point */
1678 static int fuse_get_tree_submount(struct fs_context *fsc)
1679 {
1680 struct fuse_mount *fm;
1681 struct fuse_inode *mp_fi = fsc->fs_private;
1682 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode);
1683 struct super_block *sb;
1684 int err;
1685
1686 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
1687 if (!fm)
1688 return -ENOMEM;
1689
1690 fm->fc = fuse_conn_get(fc);
1691 fsc->s_fs_info = fm;
1692 sb = sget_fc(fsc, NULL, set_anon_super_fc);
1693 if (fsc->s_fs_info)
1694 fuse_mount_destroy(fm);
1695 if (IS_ERR(sb))
1696 return PTR_ERR(sb);
1697
1698 /* Initialize superblock, making @mp_fi its root */
1699 err = fuse_fill_super_submount(sb, mp_fi);
1700 if (err) {
1701 deactivate_locked_super(sb);
1702 return err;
1703 }
1704
1705 down_write(&fc->killsb);
1706 list_add_tail(&fm->fc_entry, &fc->mounts);
1707 up_write(&fc->killsb);
1708
1709 sb->s_flags |= SB_ACTIVE;
1710 fsc->root = dget(sb->s_root);
1711
1712 return 0;
1713 }
1714
1715 static const struct fs_context_operations fuse_context_submount_ops = {
1716 .get_tree = fuse_get_tree_submount,
1717 };
1718
1719 int fuse_init_fs_context_submount(struct fs_context *fsc)
1720 {
1721 fsc->ops = &fuse_context_submount_ops;
1722 return 0;
1723 }
1724 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount);
1725
1726 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1727 {
1728 struct fuse_dev *fud = NULL;
1729 struct fuse_mount *fm = get_fuse_mount_super(sb);
1730 struct fuse_conn *fc = fm->fc;
1731 struct inode *root;
1732 struct dentry *root_dentry;
1733 int err;
1734
1735 err = -EINVAL;
1736 if (sb->s_flags & SB_MANDLOCK)
1737 goto err;
1738
1739 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc());
1740 fuse_sb_defaults(sb);
1741
1742 if (ctx->is_bdev) {
1743 #ifdef CONFIG_BLOCK
1744 err = -EINVAL;
1745 if (!sb_set_blocksize(sb, ctx->blksize))
1746 goto err;
1747 #endif
1748 } else {
1749 sb->s_blocksize = PAGE_SIZE;
1750 sb->s_blocksize_bits = PAGE_SHIFT;
1751 }
1752
1753 sb->s_subtype = ctx->subtype;
1754 ctx->subtype = NULL;
1755 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1756 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev);
1757 if (err)
1758 goto err;
1759 }
1760
1761 if (ctx->fudptr) {
1762 err = -ENOMEM;
1763 fud = fuse_dev_alloc_install(fc);
1764 if (!fud)
1765 goto err_free_dax;
1766 }
1767
1768 fc->dev = sb->s_dev;
1769 fm->sb = sb;
1770 err = fuse_bdi_init(fc, sb);
1771 if (err)
1772 goto err_dev_free;
1773
1774 /* Handle umasking inside the fuse code */
1775 if (sb->s_flags & SB_POSIXACL)
1776 fc->dont_mask = 1;
1777 sb->s_flags |= SB_POSIXACL;
1778
1779 fc->default_permissions = ctx->default_permissions;
1780 fc->allow_other = ctx->allow_other;
1781 fc->user_id = ctx->user_id;
1782 fc->group_id = ctx->group_id;
1783 fc->legacy_opts_show = ctx->legacy_opts_show;
1784 fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1785 fc->destroy = ctx->destroy;
1786 fc->no_control = ctx->no_control;
1787 fc->no_force_umount = ctx->no_force_umount;
1788
1789 err = -ENOMEM;
1790 root = fuse_get_root_inode(sb, ctx->rootmode);
1791 sb->s_d_op = &fuse_root_dentry_operations;
1792 root_dentry = d_make_root(root);
1793 if (!root_dentry)
1794 goto err_dev_free;
1795 /* Root dentry doesn't have .d_revalidate */
1796 sb->s_d_op = &fuse_dentry_operations;
1797
1798 mutex_lock(&fuse_mutex);
1799 err = -EINVAL;
1800 if (ctx->fudptr && *ctx->fudptr)
1801 goto err_unlock;
1802
1803 err = fuse_ctl_add_conn(fc);
1804 if (err)
1805 goto err_unlock;
1806
1807 list_add_tail(&fc->entry, &fuse_conn_list);
1808 sb->s_root = root_dentry;
1809 if (ctx->fudptr)
1810 *ctx->fudptr = fud;
1811 mutex_unlock(&fuse_mutex);
1812 return 0;
1813
1814 err_unlock:
1815 mutex_unlock(&fuse_mutex);
1816 dput(root_dentry);
1817 err_dev_free:
1818 if (fud)
1819 fuse_dev_free(fud);
1820 err_free_dax:
1821 if (IS_ENABLED(CONFIG_FUSE_DAX))
1822 fuse_dax_conn_free(fc);
1823 err:
1824 return err;
1825 }
1826 EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1827
1828 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1829 {
1830 struct fuse_fs_context *ctx = fsc->fs_private;
1831 int err;
1832
1833 if (!ctx->file || !ctx->rootmode_present ||
1834 !ctx->user_id_present || !ctx->group_id_present)
1835 return -EINVAL;
1836
1837 /*
1838 * Require mount to happen from the same user namespace which
1839 * opened /dev/fuse to prevent potential attacks.
1840 */
1841 if ((ctx->file->f_op != &fuse_dev_operations) ||
1842 (ctx->file->f_cred->user_ns != sb->s_user_ns))
1843 return -EINVAL;
1844 ctx->fudptr = &ctx->file->private_data;
1845
1846 err = fuse_fill_super_common(sb, ctx);
1847 if (err)
1848 return err;
1849 /* file->private_data shall be visible on all CPUs after this */
1850 smp_mb();
1851 fuse_send_init(get_fuse_mount_super(sb));
1852 return 0;
1853 }
1854
1855 /*
1856 * This is the path where user supplied an already initialized fuse dev. In
1857 * this case never create a new super if the old one is gone.
1858 */
1859 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc)
1860 {
1861 return -ENOTCONN;
1862 }
1863
1864 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc)
1865 {
1866
1867 return fsc->sget_key == get_fuse_conn_super(sb);
1868 }
1869
1870 static int fuse_get_tree(struct fs_context *fsc)
1871 {
1872 struct fuse_fs_context *ctx = fsc->fs_private;
1873 struct fuse_dev *fud;
1874 struct fuse_conn *fc;
1875 struct fuse_mount *fm;
1876 struct super_block *sb;
1877 int err;
1878
1879 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1880 if (!fc)
1881 return -ENOMEM;
1882
1883 fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1884 if (!fm) {
1885 kfree(fc);
1886 return -ENOMEM;
1887 }
1888
1889 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL);
1890 fc->release = fuse_free_conn;
1891
1892 fsc->s_fs_info = fm;
1893
1894 if (ctx->fd_present)
1895 ctx->file = fget(ctx->fd);
1896
1897 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
1898 err = get_tree_bdev(fsc, fuse_fill_super);
1899 goto out;
1900 }
1901 /*
1902 * While block dev mount can be initialized with a dummy device fd
1903 * (found by device name), normal fuse mounts can't
1904 */
1905 err = -EINVAL;
1906 if (!ctx->file)
1907 goto out;
1908
1909 /*
1910 * Allow creating a fuse mount with an already initialized fuse
1911 * connection
1912 */
1913 fud = READ_ONCE(ctx->file->private_data);
1914 if (ctx->file->f_op == &fuse_dev_operations && fud) {
1915 fsc->sget_key = fud->fc;
1916 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super);
1917 err = PTR_ERR_OR_ZERO(sb);
1918 if (!IS_ERR(sb))
1919 fsc->root = dget(sb->s_root);
1920 } else {
1921 err = get_tree_nodev(fsc, fuse_fill_super);
1922 }
1923 out:
1924 if (fsc->s_fs_info)
1925 fuse_mount_destroy(fm);
1926 if (ctx->file)
1927 fput(ctx->file);
1928 return err;
1929 }
1930
1931 static const struct fs_context_operations fuse_context_ops = {
1932 .free = fuse_free_fsc,
1933 .parse_param = fuse_parse_param,
1934 .reconfigure = fuse_reconfigure,
1935 .get_tree = fuse_get_tree,
1936 };
1937
1938 /*
1939 * Set up the filesystem mount context.
1940 */
1941 static int fuse_init_fs_context(struct fs_context *fsc)
1942 {
1943 struct fuse_fs_context *ctx;
1944
1945 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1946 if (!ctx)
1947 return -ENOMEM;
1948
1949 ctx->max_read = ~0;
1950 ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1951 ctx->legacy_opts_show = true;
1952
1953 #ifdef CONFIG_BLOCK
1954 if (fsc->fs_type == &fuseblk_fs_type) {
1955 ctx->is_bdev = true;
1956 ctx->destroy = true;
1957 }
1958 #endif
1959
1960 fsc->fs_private = ctx;
1961 fsc->ops = &fuse_context_ops;
1962 return 0;
1963 }
1964
1965 bool fuse_mount_remove(struct fuse_mount *fm)
1966 {
1967 struct fuse_conn *fc = fm->fc;
1968 bool last = false;
1969
1970 down_write(&fc->killsb);
1971 list_del_init(&fm->fc_entry);
1972 if (list_empty(&fc->mounts))
1973 last = true;
1974 up_write(&fc->killsb);
1975
1976 return last;
1977 }
1978 EXPORT_SYMBOL_GPL(fuse_mount_remove);
1979
1980 void fuse_conn_destroy(struct fuse_mount *fm)
1981 {
1982 struct fuse_conn *fc = fm->fc;
1983
1984 if (fc->destroy)
1985 fuse_send_destroy(fm);
1986
1987 fuse_abort_conn(fc);
1988 fuse_wait_aborted(fc);
1989
1990 if (!list_empty(&fc->entry)) {
1991 mutex_lock(&fuse_mutex);
1992 list_del(&fc->entry);
1993 fuse_ctl_remove_conn(fc);
1994 mutex_unlock(&fuse_mutex);
1995 }
1996 }
1997 EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1998
1999 static void fuse_sb_destroy(struct super_block *sb)
2000 {
2001 struct fuse_mount *fm = get_fuse_mount_super(sb);
2002 bool last;
2003
2004 if (sb->s_root) {
2005 last = fuse_mount_remove(fm);
2006 if (last)
2007 fuse_conn_destroy(fm);
2008 }
2009 }
2010
2011 void fuse_mount_destroy(struct fuse_mount *fm)
2012 {
2013 fuse_conn_put(fm->fc);
2014 kfree_rcu(fm, rcu);
2015 }
2016 EXPORT_SYMBOL(fuse_mount_destroy);
2017
2018 static void fuse_kill_sb_anon(struct super_block *sb)
2019 {
2020 fuse_sb_destroy(sb);
2021 kill_anon_super(sb);
2022 fuse_mount_destroy(get_fuse_mount_super(sb));
2023 }
2024
2025 static struct file_system_type fuse_fs_type = {
2026 .owner = THIS_MODULE,
2027 .name = "fuse",
2028 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT | FS_ALLOW_IDMAP,
2029 .init_fs_context = fuse_init_fs_context,
2030 .parameters = fuse_fs_parameters,
2031 .kill_sb = fuse_kill_sb_anon,
2032 };
2033 MODULE_ALIAS_FS("fuse");
2034
2035 #ifdef CONFIG_BLOCK
2036 static void fuse_kill_sb_blk(struct super_block *sb)
2037 {
2038 fuse_sb_destroy(sb);
2039 kill_block_super(sb);
2040 fuse_mount_destroy(get_fuse_mount_super(sb));
2041 }
2042
2043 static struct file_system_type fuseblk_fs_type = {
2044 .owner = THIS_MODULE,
2045 .name = "fuseblk",
2046 .init_fs_context = fuse_init_fs_context,
2047 .parameters = fuse_fs_parameters,
2048 .kill_sb = fuse_kill_sb_blk,
2049 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE | FS_ALLOW_IDMAP,
2050 };
2051 MODULE_ALIAS_FS("fuseblk");
2052
2053 static inline int register_fuseblk(void)
2054 {
2055 return register_filesystem(&fuseblk_fs_type);
2056 }
2057
2058 static inline void unregister_fuseblk(void)
2059 {
2060 unregister_filesystem(&fuseblk_fs_type);
2061 }
2062 #else
2063 static inline int register_fuseblk(void)
2064 {
2065 return 0;
2066 }
2067
2068 static inline void unregister_fuseblk(void)
2069 {
2070 }
2071 #endif
2072
2073 static void fuse_inode_init_once(void *foo)
2074 {
2075 struct inode *inode = foo;
2076
2077 inode_init_once(inode);
2078 }
2079
2080 static int __init fuse_fs_init(void)
2081 {
2082 int err;
2083
2084 fuse_inode_cachep = kmem_cache_create("fuse_inode",
2085 sizeof(struct fuse_inode), 0,
2086 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
2087 fuse_inode_init_once);
2088 err = -ENOMEM;
2089 if (!fuse_inode_cachep)
2090 goto out;
2091
2092 err = register_fuseblk();
2093 if (err)
2094 goto out2;
2095
2096 err = register_filesystem(&fuse_fs_type);
2097 if (err)
2098 goto out3;
2099
2100 err = fuse_sysctl_register();
2101 if (err)
2102 goto out4;
2103
2104 return 0;
2105
2106 out4:
2107 unregister_filesystem(&fuse_fs_type);
2108 out3:
2109 unregister_fuseblk();
2110 out2:
2111 kmem_cache_destroy(fuse_inode_cachep);
2112 out:
2113 return err;
2114 }
2115
2116 static void fuse_fs_cleanup(void)
2117 {
2118 fuse_sysctl_unregister();
2119 unregister_filesystem(&fuse_fs_type);
2120 unregister_fuseblk();
2121
2122 /*
2123 * Make sure all delayed rcu free inodes are flushed before we
2124 * destroy cache.
2125 */
2126 rcu_barrier();
2127 kmem_cache_destroy(fuse_inode_cachep);
2128 }
2129
2130 static struct kobject *fuse_kobj;
2131
2132 static int fuse_sysfs_init(void)
2133 {
2134 int err;
2135
2136 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
2137 if (!fuse_kobj) {
2138 err = -ENOMEM;
2139 goto out_err;
2140 }
2141
2142 err = sysfs_create_mount_point(fuse_kobj, "connections");
2143 if (err)
2144 goto out_fuse_unregister;
2145
2146 return 0;
2147
2148 out_fuse_unregister:
2149 kobject_put(fuse_kobj);
2150 out_err:
2151 return err;
2152 }
2153
2154 static void fuse_sysfs_cleanup(void)
2155 {
2156 sysfs_remove_mount_point(fuse_kobj, "connections");
2157 kobject_put(fuse_kobj);
2158 }
2159
2160 static int __init fuse_init(void)
2161 {
2162 int res;
2163
2164 pr_info("init (API version %i.%i)\n",
2165 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
2166
2167 INIT_LIST_HEAD(&fuse_conn_list);
2168 res = fuse_fs_init();
2169 if (res)
2170 goto err;
2171
2172 res = fuse_dev_init();
2173 if (res)
2174 goto err_fs_cleanup;
2175
2176 res = fuse_sysfs_init();
2177 if (res)
2178 goto err_dev_cleanup;
2179
2180 res = fuse_ctl_init();
2181 if (res)
2182 goto err_sysfs_cleanup;
2183
2184 sanitize_global_limit(&max_user_bgreq);
2185 sanitize_global_limit(&max_user_congthresh);
2186
2187 return 0;
2188
2189 err_sysfs_cleanup:
2190 fuse_sysfs_cleanup();
2191 err_dev_cleanup:
2192 fuse_dev_cleanup();
2193 err_fs_cleanup:
2194 fuse_fs_cleanup();
2195 err:
2196 return res;
2197 }
2198
2199 static void __exit fuse_exit(void)
2200 {
2201 pr_debug("exit\n");
2202
2203 fuse_ctl_cleanup();
2204 fuse_sysfs_cleanup();
2205 fuse_fs_cleanup();
2206 fuse_dev_cleanup();
2207 }
2208
2209 module_init(fuse_init);
2210 module_exit(fuse_exit);
Linux Kernel