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Merge tag 'regmap-fix-v5.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux/fpc-iii.git] / fs / fuse / inode.c
blobb0e18b470e918dc04154e7def993e84cf610eb6b
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
27 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
28 MODULE_DESCRIPTION("Filesystem in Userspace");
29 MODULE_LICENSE("GPL");
30
31 static struct kmem_cache *fuse_inode_cachep;
32 struct list_head fuse_conn_list;
33 DEFINE_MUTEX(fuse_mutex);
34
35 static int set_global_limit(const char *val, const struct kernel_param *kp);
36
37 unsigned max_user_bgreq;
38 module_param_call(max_user_bgreq, set_global_limit, param_get_uint,
39 &max_user_bgreq, 0644);
40 __MODULE_PARM_TYPE(max_user_bgreq, "uint");
41 MODULE_PARM_DESC(max_user_bgreq,
42 "Global limit for the maximum number of backgrounded requests an "
43 "unprivileged user can set");
44
45 unsigned max_user_congthresh;
46 module_param_call(max_user_congthresh, set_global_limit, param_get_uint,
47 &max_user_congthresh, 0644);
48 __MODULE_PARM_TYPE(max_user_congthresh, "uint");
49 MODULE_PARM_DESC(max_user_congthresh,
50 "Global limit for the maximum congestion threshold an "
51 "unprivileged user can set");
52
53 #define FUSE_SUPER_MAGIC 0x65735546
54
55 #define FUSE_DEFAULT_BLKSIZE 512
56
57 /** Maximum number of outstanding background requests */
58 #define FUSE_DEFAULT_MAX_BACKGROUND 12
59
60 /** Congestion starts at 75% of maximum */
61 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4)
62
63 #ifdef CONFIG_BLOCK
64 static struct file_system_type fuseblk_fs_type;
65 #endif
66
67 struct fuse_forget_link *fuse_alloc_forget(void)
68 {
69 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT);
70 }
71
72 static struct inode *fuse_alloc_inode(struct super_block *sb)
73 {
74 struct fuse_inode *fi;
75
76 fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
77 if (!fi)
78 return NULL;
79
80 fi->i_time = 0;
81 fi->inval_mask = 0;
82 fi->nodeid = 0;
83 fi->nlookup = 0;
84 fi->attr_version = 0;
85 fi->orig_ino = 0;
86 fi->state = 0;
87 mutex_init(&fi->mutex);
88 init_rwsem(&fi->i_mmap_sem);
89 spin_lock_init(&fi->lock);
90 fi->forget = fuse_alloc_forget();
91 if (!fi->forget)
92 goto out_free;
93
94 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi))
95 goto out_free_forget;
96
97 return &fi->inode;
98
99 out_free_forget:
100 kfree(fi->forget);
101 out_free:
102 kmem_cache_free(fuse_inode_cachep, fi);
103 return NULL;
104 }
105
106 static void fuse_free_inode(struct inode *inode)
107 {
108 struct fuse_inode *fi = get_fuse_inode(inode);
109
110 mutex_destroy(&fi->mutex);
111 kfree(fi->forget);
112 #ifdef CONFIG_FUSE_DAX
113 kfree(fi->dax);
114 #endif
115 kmem_cache_free(fuse_inode_cachep, fi);
116 }
117
118 static void fuse_evict_inode(struct inode *inode)
119 {
120 struct fuse_inode *fi = get_fuse_inode(inode);
121
122 truncate_inode_pages_final(&inode->i_data);
123 clear_inode(inode);
124 if (inode->i_sb->s_flags & SB_ACTIVE) {
125 struct fuse_conn *fc = get_fuse_conn(inode);
126
127 if (FUSE_IS_DAX(inode))
128 fuse_dax_inode_cleanup(inode);
129 if (fi->nlookup) {
130 fuse_queue_forget(fc, fi->forget, fi->nodeid,
131 fi->nlookup);
132 fi->forget = NULL;
133 }
134 }
135 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) {
136 WARN_ON(!list_empty(&fi->write_files));
137 WARN_ON(!list_empty(&fi->queued_writes));
138 }
139 }
140
141 static int fuse_reconfigure(struct fs_context *fc)
142 {
143 struct super_block *sb = fc->root->d_sb;
144
145 sync_filesystem(sb);
146 if (fc->sb_flags & SB_MANDLOCK)
147 return -EINVAL;
148
149 return 0;
150 }
151
152 /*
153 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
154 * so that it will fit.
155 */
156 static ino_t fuse_squash_ino(u64 ino64)
157 {
158 ino_t ino = (ino_t) ino64;
159 if (sizeof(ino_t) < sizeof(u64))
160 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8;
161 return ino;
162 }
163
164 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
165 u64 attr_valid)
166 {
167 struct fuse_conn *fc = get_fuse_conn(inode);
168 struct fuse_inode *fi = get_fuse_inode(inode);
169
170 lockdep_assert_held(&fi->lock);
171
172 fi->attr_version = atomic64_inc_return(&fc->attr_version);
173 fi->i_time = attr_valid;
174 WRITE_ONCE(fi->inval_mask, 0);
175
176 inode->i_ino = fuse_squash_ino(attr->ino);
177 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
178 set_nlink(inode, attr->nlink);
179 inode->i_uid = make_kuid(fc->user_ns, attr->uid);
180 inode->i_gid = make_kgid(fc->user_ns, attr->gid);
181 inode->i_blocks = attr->blocks;
182 inode->i_atime.tv_sec = attr->atime;
183 inode->i_atime.tv_nsec = attr->atimensec;
184 /* mtime from server may be stale due to local buffered write */
185 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) {
186 inode->i_mtime.tv_sec = attr->mtime;
187 inode->i_mtime.tv_nsec = attr->mtimensec;
188 inode->i_ctime.tv_sec = attr->ctime;
189 inode->i_ctime.tv_nsec = attr->ctimensec;
190 }
191
192 if (attr->blksize != 0)
193 inode->i_blkbits = ilog2(attr->blksize);
194 else
195 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
196
197 /*
198 * Don't set the sticky bit in i_mode, unless we want the VFS
199 * to check permissions. This prevents failures due to the
200 * check in may_delete().
201 */
202 fi->orig_i_mode = inode->i_mode;
203 if (!fc->default_permissions)
204 inode->i_mode &= ~S_ISVTX;
205
206 fi->orig_ino = attr->ino;
207
208 /*
209 * We are refreshing inode data and it is possible that another
210 * client set suid/sgid or security.capability xattr. So clear
211 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid
212 * was set or if security.capability xattr was set. But we don't
213 * know if security.capability has been set or not. So clear it
214 * anyway. Its less efficient but should be safe.
215 */
216 inode->i_flags &= ~S_NOSEC;
217 }
218
219 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
220 u64 attr_valid, u64 attr_version)
221 {
222 struct fuse_conn *fc = get_fuse_conn(inode);
223 struct fuse_inode *fi = get_fuse_inode(inode);
224 bool is_wb = fc->writeback_cache;
225 loff_t oldsize;
226 struct timespec64 old_mtime;
227
228 spin_lock(&fi->lock);
229 if ((attr_version != 0 && fi->attr_version > attr_version) ||
230 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
231 spin_unlock(&fi->lock);
232 return;
233 }
234
235 old_mtime = inode->i_mtime;
236 fuse_change_attributes_common(inode, attr, attr_valid);
237
238 oldsize = inode->i_size;
239 /*
240 * In case of writeback_cache enabled, the cached writes beyond EOF
241 * extend local i_size without keeping userspace server in sync. So,
242 * attr->size coming from server can be stale. We cannot trust it.
243 */
244 if (!is_wb || !S_ISREG(inode->i_mode))
245 i_size_write(inode, attr->size);
246 spin_unlock(&fi->lock);
247
248 if (!is_wb && S_ISREG(inode->i_mode)) {
249 bool inval = false;
250
251 if (oldsize != attr->size) {
252 truncate_pagecache(inode, attr->size);
253 if (!fc->explicit_inval_data)
254 inval = true;
255 } else if (fc->auto_inval_data) {
256 struct timespec64 new_mtime = {
257 .tv_sec = attr->mtime,
258 .tv_nsec = attr->mtimensec,
259 };
260
261 /*
262 * Auto inval mode also checks and invalidates if mtime
263 * has changed.
264 */
265 if (!timespec64_equal(&old_mtime, &new_mtime))
266 inval = true;
267 }
268
269 if (inval)
270 invalidate_inode_pages2(inode->i_mapping);
271 }
272 }
273
274 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
275 {
276 inode->i_mode = attr->mode & S_IFMT;
277 inode->i_size = attr->size;
278 inode->i_mtime.tv_sec = attr->mtime;
279 inode->i_mtime.tv_nsec = attr->mtimensec;
280 inode->i_ctime.tv_sec = attr->ctime;
281 inode->i_ctime.tv_nsec = attr->ctimensec;
282 if (S_ISREG(inode->i_mode)) {
283 fuse_init_common(inode);
284 fuse_init_file_inode(inode);
285 } else if (S_ISDIR(inode->i_mode))
286 fuse_init_dir(inode);
287 else if (S_ISLNK(inode->i_mode))
288 fuse_init_symlink(inode);
289 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
290 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
291 fuse_init_common(inode);
292 init_special_inode(inode, inode->i_mode,
293 new_decode_dev(attr->rdev));
294 } else
295 BUG();
296 }
297
298 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
299 {
300 u64 nodeid = *(u64 *) _nodeidp;
301 if (get_node_id(inode) == nodeid)
302 return 1;
303 else
304 return 0;
305 }
306
307 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
308 {
309 u64 nodeid = *(u64 *) _nodeidp;
310 get_fuse_inode(inode)->nodeid = nodeid;
311 return 0;
312 }
313
314 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
315 int generation, struct fuse_attr *attr,
316 u64 attr_valid, u64 attr_version)
317 {
318 struct inode *inode;
319 struct fuse_inode *fi;
320 struct fuse_conn *fc = get_fuse_conn_super(sb);
321
322 /*
323 * Auto mount points get their node id from the submount root, which is
324 * not a unique identifier within this filesystem.
325 *
326 * To avoid conflicts, do not place submount points into the inode hash
327 * table.
328 */
329 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) &&
330 S_ISDIR(attr->mode)) {
331 inode = new_inode(sb);
332 if (!inode)
333 return NULL;
334
335 fuse_init_inode(inode, attr);
336 get_fuse_inode(inode)->nodeid = nodeid;
337 inode->i_flags |= S_AUTOMOUNT;
338 goto done;
339 }
340
341 retry:
342 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
343 if (!inode)
344 return NULL;
345
346 if ((inode->i_state & I_NEW)) {
347 inode->i_flags |= S_NOATIME;
348 if (!fc->writeback_cache || !S_ISREG(attr->mode))
349 inode->i_flags |= S_NOCMTIME;
350 inode->i_generation = generation;
351 fuse_init_inode(inode, attr);
352 unlock_new_inode(inode);
353 } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
354 /* Inode has changed type, any I/O on the old should fail */
355 fuse_make_bad(inode);
356 iput(inode);
357 goto retry;
358 }
359 done:
360 fi = get_fuse_inode(inode);
361 spin_lock(&fi->lock);
362 fi->nlookup++;
363 spin_unlock(&fi->lock);
364 fuse_change_attributes(inode, attr, attr_valid, attr_version);
365
366 return inode;
367 }
368
369 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid,
370 struct fuse_mount **fm)
371 {
372 struct fuse_mount *fm_iter;
373 struct inode *inode;
374
375 WARN_ON(!rwsem_is_locked(&fc->killsb));
376 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) {
377 if (!fm_iter->sb)
378 continue;
379
380 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid);
381 if (inode) {
382 if (fm)
383 *fm = fm_iter;
384 return inode;
385 }
386 }
387
388 return NULL;
389 }
390
391 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid,
392 loff_t offset, loff_t len)
393 {
394 struct fuse_inode *fi;
395 struct inode *inode;
396 pgoff_t pg_start;
397 pgoff_t pg_end;
398
399 inode = fuse_ilookup(fc, nodeid, NULL);
400 if (!inode)
401 return -ENOENT;
402
403 fi = get_fuse_inode(inode);
404 spin_lock(&fi->lock);
405 fi->attr_version = atomic64_inc_return(&fc->attr_version);
406 spin_unlock(&fi->lock);
407
408 fuse_invalidate_attr(inode);
409 forget_all_cached_acls(inode);
410 if (offset >= 0) {
411 pg_start = offset >> PAGE_SHIFT;
412 if (len <= 0)
413 pg_end = -1;
414 else
415 pg_end = (offset + len - 1) >> PAGE_SHIFT;
416 invalidate_inode_pages2_range(inode->i_mapping,
417 pg_start, pg_end);
418 }
419 iput(inode);
420 return 0;
421 }
422
423 bool fuse_lock_inode(struct inode *inode)
424 {
425 bool locked = false;
426
427 if (!get_fuse_conn(inode)->parallel_dirops) {
428 mutex_lock(&get_fuse_inode(inode)->mutex);
429 locked = true;
430 }
431
432 return locked;
433 }
434
435 void fuse_unlock_inode(struct inode *inode, bool locked)
436 {
437 if (locked)
438 mutex_unlock(&get_fuse_inode(inode)->mutex);
439 }
440
441 static void fuse_umount_begin(struct super_block *sb)
442 {
443 struct fuse_conn *fc = get_fuse_conn_super(sb);
444
445 if (!fc->no_force_umount)
446 fuse_abort_conn(fc);
447 }
448
449 static void fuse_send_destroy(struct fuse_mount *fm)
450 {
451 if (fm->fc->conn_init) {
452 FUSE_ARGS(args);
453
454 args.opcode = FUSE_DESTROY;
455 args.force = true;
456 args.nocreds = true;
457 fuse_simple_request(fm, &args);
458 }
459 }
460
461 static void fuse_put_super(struct super_block *sb)
462 {
463 struct fuse_mount *fm = get_fuse_mount_super(sb);
464
465 fuse_conn_put(fm->fc);
466 kfree(fm);
467 }
468
469 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
470 {
471 stbuf->f_type = FUSE_SUPER_MAGIC;
472 stbuf->f_bsize = attr->bsize;
473 stbuf->f_frsize = attr->frsize;
474 stbuf->f_blocks = attr->blocks;
475 stbuf->f_bfree = attr->bfree;
476 stbuf->f_bavail = attr->bavail;
477 stbuf->f_files = attr->files;
478 stbuf->f_ffree = attr->ffree;
479 stbuf->f_namelen = attr->namelen;
480 /* fsid is left zero */
481 }
482
483 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
484 {
485 struct super_block *sb = dentry->d_sb;
486 struct fuse_mount *fm = get_fuse_mount_super(sb);
487 FUSE_ARGS(args);
488 struct fuse_statfs_out outarg;
489 int err;
490
491 if (!fuse_allow_current_process(fm->fc)) {
492 buf->f_type = FUSE_SUPER_MAGIC;
493 return 0;
494 }
495
496 memset(&outarg, 0, sizeof(outarg));
497 args.in_numargs = 0;
498 args.opcode = FUSE_STATFS;
499 args.nodeid = get_node_id(d_inode(dentry));
500 args.out_numargs = 1;
501 args.out_args[0].size = sizeof(outarg);
502 args.out_args[0].value = &outarg;
503 err = fuse_simple_request(fm, &args);
504 if (!err)
505 convert_fuse_statfs(buf, &outarg.st);
506 return err;
507 }
508
509 enum {
510 OPT_SOURCE,
511 OPT_SUBTYPE,
512 OPT_FD,
513 OPT_ROOTMODE,
514 OPT_USER_ID,
515 OPT_GROUP_ID,
516 OPT_DEFAULT_PERMISSIONS,
517 OPT_ALLOW_OTHER,
518 OPT_MAX_READ,
519 OPT_BLKSIZE,
520 OPT_ERR
521 };
522
523 static const struct fs_parameter_spec fuse_fs_parameters[] = {
524 fsparam_string ("source", OPT_SOURCE),
525 fsparam_u32 ("fd", OPT_FD),
526 fsparam_u32oct ("rootmode", OPT_ROOTMODE),
527 fsparam_u32 ("user_id", OPT_USER_ID),
528 fsparam_u32 ("group_id", OPT_GROUP_ID),
529 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS),
530 fsparam_flag ("allow_other", OPT_ALLOW_OTHER),
531 fsparam_u32 ("max_read", OPT_MAX_READ),
532 fsparam_u32 ("blksize", OPT_BLKSIZE),
533 fsparam_string ("subtype", OPT_SUBTYPE),
534 {}
535 };
536
537 static int fuse_parse_param(struct fs_context *fc, struct fs_parameter *param)
538 {
539 struct fs_parse_result result;
540 struct fuse_fs_context *ctx = fc->fs_private;
541 int opt;
542
543 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
544 /*
545 * Ignore options coming from mount(MS_REMOUNT) for backward
546 * compatibility.
547 */
548 if (fc->oldapi)
549 return 0;
550
551 return invalfc(fc, "No changes allowed in reconfigure");
552 }
553
554 opt = fs_parse(fc, fuse_fs_parameters, param, &result);
555 if (opt < 0)
556 return opt;
557
558 switch (opt) {
559 case OPT_SOURCE:
560 if (fc->source)
561 return invalfc(fc, "Multiple sources specified");
562 fc->source = param->string;
563 param->string = NULL;
564 break;
565
566 case OPT_SUBTYPE:
567 if (ctx->subtype)
568 return invalfc(fc, "Multiple subtypes specified");
569 ctx->subtype = param->string;
570 param->string = NULL;
571 return 0;
572
573 case OPT_FD:
574 ctx->fd = result.uint_32;
575 ctx->fd_present = true;
576 break;
577
578 case OPT_ROOTMODE:
579 if (!fuse_valid_type(result.uint_32))
580 return invalfc(fc, "Invalid rootmode");
581 ctx->rootmode = result.uint_32;
582 ctx->rootmode_present = true;
583 break;
584
585 case OPT_USER_ID:
586 ctx->user_id = make_kuid(fc->user_ns, result.uint_32);
587 if (!uid_valid(ctx->user_id))
588 return invalfc(fc, "Invalid user_id");
589 ctx->user_id_present = true;
590 break;
591
592 case OPT_GROUP_ID:
593 ctx->group_id = make_kgid(fc->user_ns, result.uint_32);
594 if (!gid_valid(ctx->group_id))
595 return invalfc(fc, "Invalid group_id");
596 ctx->group_id_present = true;
597 break;
598
599 case OPT_DEFAULT_PERMISSIONS:
600 ctx->default_permissions = true;
601 break;
602
603 case OPT_ALLOW_OTHER:
604 ctx->allow_other = true;
605 break;
606
607 case OPT_MAX_READ:
608 ctx->max_read = result.uint_32;
609 break;
610
611 case OPT_BLKSIZE:
612 if (!ctx->is_bdev)
613 return invalfc(fc, "blksize only supported for fuseblk");
614 ctx->blksize = result.uint_32;
615 break;
616
617 default:
618 return -EINVAL;
619 }
620
621 return 0;
622 }
623
624 static void fuse_free_fc(struct fs_context *fc)
625 {
626 struct fuse_fs_context *ctx = fc->fs_private;
627
628 if (ctx) {
629 kfree(ctx->subtype);
630 kfree(ctx);
631 }
632 }
633
634 static int fuse_show_options(struct seq_file *m, struct dentry *root)
635 {
636 struct super_block *sb = root->d_sb;
637 struct fuse_conn *fc = get_fuse_conn_super(sb);
638
639 if (fc->legacy_opts_show) {
640 seq_printf(m, ",user_id=%u",
641 from_kuid_munged(fc->user_ns, fc->user_id));
642 seq_printf(m, ",group_id=%u",
643 from_kgid_munged(fc->user_ns, fc->group_id));
644 if (fc->default_permissions)
645 seq_puts(m, ",default_permissions");
646 if (fc->allow_other)
647 seq_puts(m, ",allow_other");
648 if (fc->max_read != ~0)
649 seq_printf(m, ",max_read=%u", fc->max_read);
650 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
651 seq_printf(m, ",blksize=%lu", sb->s_blocksize);
652 }
653 #ifdef CONFIG_FUSE_DAX
654 if (fc->dax)
655 seq_puts(m, ",dax");
656 #endif
657
658 return 0;
659 }
660
661 static void fuse_iqueue_init(struct fuse_iqueue *fiq,
662 const struct fuse_iqueue_ops *ops,
663 void *priv)
664 {
665 memset(fiq, 0, sizeof(struct fuse_iqueue));
666 spin_lock_init(&fiq->lock);
667 init_waitqueue_head(&fiq->waitq);
668 INIT_LIST_HEAD(&fiq->pending);
669 INIT_LIST_HEAD(&fiq->interrupts);
670 fiq->forget_list_tail = &fiq->forget_list_head;
671 fiq->connected = 1;
672 fiq->ops = ops;
673 fiq->priv = priv;
674 }
675
676 static void fuse_pqueue_init(struct fuse_pqueue *fpq)
677 {
678 unsigned int i;
679
680 spin_lock_init(&fpq->lock);
681 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
682 INIT_LIST_HEAD(&fpq->processing[i]);
683 INIT_LIST_HEAD(&fpq->io);
684 fpq->connected = 1;
685 }
686
687 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
688 struct user_namespace *user_ns,
689 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv)
690 {
691 memset(fc, 0, sizeof(*fc));
692 spin_lock_init(&fc->lock);
693 spin_lock_init(&fc->bg_lock);
694 init_rwsem(&fc->killsb);
695 refcount_set(&fc->count, 1);
696 atomic_set(&fc->dev_count, 1);
697 init_waitqueue_head(&fc->blocked_waitq);
698 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv);
699 INIT_LIST_HEAD(&fc->bg_queue);
700 INIT_LIST_HEAD(&fc->entry);
701 INIT_LIST_HEAD(&fc->devices);
702 atomic_set(&fc->num_waiting, 0);
703 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND;
704 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD;
705 atomic64_set(&fc->khctr, 0);
706 fc->polled_files = RB_ROOT;
707 fc->blocked = 0;
708 fc->initialized = 0;
709 fc->connected = 1;
710 atomic64_set(&fc->attr_version, 1);
711 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
712 fc->pid_ns = get_pid_ns(task_active_pid_ns(current));
713 fc->user_ns = get_user_ns(user_ns);
714 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ;
715
716 INIT_LIST_HEAD(&fc->mounts);
717 list_add(&fm->fc_entry, &fc->mounts);
718 fm->fc = fc;
719 }
720 EXPORT_SYMBOL_GPL(fuse_conn_init);
721
722 void fuse_conn_put(struct fuse_conn *fc)
723 {
724 if (refcount_dec_and_test(&fc->count)) {
725 struct fuse_iqueue *fiq = &fc->iq;
726
727 if (IS_ENABLED(CONFIG_FUSE_DAX))
728 fuse_dax_conn_free(fc);
729 if (fiq->ops->release)
730 fiq->ops->release(fiq);
731 put_pid_ns(fc->pid_ns);
732 put_user_ns(fc->user_ns);
733 fc->release(fc);
734 }
735 }
736 EXPORT_SYMBOL_GPL(fuse_conn_put);
737
738 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
739 {
740 refcount_inc(&fc->count);
741 return fc;
742 }
743 EXPORT_SYMBOL_GPL(fuse_conn_get);
744
745 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
746 {
747 struct fuse_attr attr;
748 memset(&attr, 0, sizeof(attr));
749
750 attr.mode = mode;
751 attr.ino = FUSE_ROOT_ID;
752 attr.nlink = 1;
753 return fuse_iget(sb, 1, 0, &attr, 0, 0);
754 }
755
756 struct fuse_inode_handle {
757 u64 nodeid;
758 u32 generation;
759 };
760
761 static struct dentry *fuse_get_dentry(struct super_block *sb,
762 struct fuse_inode_handle *handle)
763 {
764 struct fuse_conn *fc = get_fuse_conn_super(sb);
765 struct inode *inode;
766 struct dentry *entry;
767 int err = -ESTALE;
768
769 if (handle->nodeid == 0)
770 goto out_err;
771
772 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
773 if (!inode) {
774 struct fuse_entry_out outarg;
775 const struct qstr name = QSTR_INIT(".", 1);
776
777 if (!fc->export_support)
778 goto out_err;
779
780 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
781 &inode);
782 if (err && err != -ENOENT)
783 goto out_err;
784 if (err || !inode) {
785 err = -ESTALE;
786 goto out_err;
787 }
788 err = -EIO;
789 if (get_node_id(inode) != handle->nodeid)
790 goto out_iput;
791 }
792 err = -ESTALE;
793 if (inode->i_generation != handle->generation)
794 goto out_iput;
795
796 entry = d_obtain_alias(inode);
797 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
798 fuse_invalidate_entry_cache(entry);
799
800 return entry;
801
802 out_iput:
803 iput(inode);
804 out_err:
805 return ERR_PTR(err);
806 }
807
808 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len,
809 struct inode *parent)
810 {
811 int len = parent ? 6 : 3;
812 u64 nodeid;
813 u32 generation;
814
815 if (*max_len < len) {
816 *max_len = len;
817 return FILEID_INVALID;
818 }
819
820 nodeid = get_fuse_inode(inode)->nodeid;
821 generation = inode->i_generation;
822
823 fh[0] = (u32)(nodeid >> 32);
824 fh[1] = (u32)(nodeid & 0xffffffff);
825 fh[2] = generation;
826
827 if (parent) {
828 nodeid = get_fuse_inode(parent)->nodeid;
829 generation = parent->i_generation;
830
831 fh[3] = (u32)(nodeid >> 32);
832 fh[4] = (u32)(nodeid & 0xffffffff);
833 fh[5] = generation;
834 }
835
836 *max_len = len;
837 return parent ? 0x82 : 0x81;
838 }
839
840 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
841 struct fid *fid, int fh_len, int fh_type)
842 {
843 struct fuse_inode_handle handle;
844
845 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
846 return NULL;
847
848 handle.nodeid = (u64) fid->raw[0] << 32;
849 handle.nodeid |= (u64) fid->raw[1];
850 handle.generation = fid->raw[2];
851 return fuse_get_dentry(sb, &handle);
852 }
853
854 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
855 struct fid *fid, int fh_len, int fh_type)
856 {
857 struct fuse_inode_handle parent;
858
859 if (fh_type != 0x82 || fh_len < 6)
860 return NULL;
861
862 parent.nodeid = (u64) fid->raw[3] << 32;
863 parent.nodeid |= (u64) fid->raw[4];
864 parent.generation = fid->raw[5];
865 return fuse_get_dentry(sb, &parent);
866 }
867
868 static struct dentry *fuse_get_parent(struct dentry *child)
869 {
870 struct inode *child_inode = d_inode(child);
871 struct fuse_conn *fc = get_fuse_conn(child_inode);
872 struct inode *inode;
873 struct dentry *parent;
874 struct fuse_entry_out outarg;
875 const struct qstr name = QSTR_INIT("..", 2);
876 int err;
877
878 if (!fc->export_support)
879 return ERR_PTR(-ESTALE);
880
881 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
882 &name, &outarg, &inode);
883 if (err) {
884 if (err == -ENOENT)
885 return ERR_PTR(-ESTALE);
886 return ERR_PTR(err);
887 }
888
889 parent = d_obtain_alias(inode);
890 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
891 fuse_invalidate_entry_cache(parent);
892
893 return parent;
894 }
895
896 static const struct export_operations fuse_export_operations = {
897 .fh_to_dentry = fuse_fh_to_dentry,
898 .fh_to_parent = fuse_fh_to_parent,
899 .encode_fh = fuse_encode_fh,
900 .get_parent = fuse_get_parent,
901 };
902
903 static const struct super_operations fuse_super_operations = {
904 .alloc_inode = fuse_alloc_inode,
905 .free_inode = fuse_free_inode,
906 .evict_inode = fuse_evict_inode,
907 .write_inode = fuse_write_inode,
908 .drop_inode = generic_delete_inode,
909 .put_super = fuse_put_super,
910 .umount_begin = fuse_umount_begin,
911 .statfs = fuse_statfs,
912 .show_options = fuse_show_options,
913 };
914
915 static void sanitize_global_limit(unsigned *limit)
916 {
917 /*
918 * The default maximum number of async requests is calculated to consume
919 * 1/2^13 of the total memory, assuming 392 bytes per request.
920 */
921 if (*limit == 0)
922 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392;
923
924 if (*limit >= 1 << 16)
925 *limit = (1 << 16) - 1;
926 }
927
928 static int set_global_limit(const char *val, const struct kernel_param *kp)
929 {
930 int rv;
931
932 rv = param_set_uint(val, kp);
933 if (rv)
934 return rv;
935
936 sanitize_global_limit((unsigned *)kp->arg);
937
938 return 0;
939 }
940
941 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg)
942 {
943 int cap_sys_admin = capable(CAP_SYS_ADMIN);
944
945 if (arg->minor < 13)
946 return;
947
948 sanitize_global_limit(&max_user_bgreq);
949 sanitize_global_limit(&max_user_congthresh);
950
951 spin_lock(&fc->bg_lock);
952 if (arg->max_background) {
953 fc->max_background = arg->max_background;
954
955 if (!cap_sys_admin && fc->max_background > max_user_bgreq)
956 fc->max_background = max_user_bgreq;
957 }
958 if (arg->congestion_threshold) {
959 fc->congestion_threshold = arg->congestion_threshold;
960
961 if (!cap_sys_admin &&
962 fc->congestion_threshold > max_user_congthresh)
963 fc->congestion_threshold = max_user_congthresh;
964 }
965 spin_unlock(&fc->bg_lock);
966 }
967
968 struct fuse_init_args {
969 struct fuse_args args;
970 struct fuse_init_in in;
971 struct fuse_init_out out;
972 };
973
974 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
975 int error)
976 {
977 struct fuse_conn *fc = fm->fc;
978 struct fuse_init_args *ia = container_of(args, typeof(*ia), args);
979 struct fuse_init_out *arg = &ia->out;
980 bool ok = true;
981
982 if (error || arg->major != FUSE_KERNEL_VERSION)
983 ok = false;
984 else {
985 unsigned long ra_pages;
986
987 process_init_limits(fc, arg);
988
989 if (arg->minor >= 6) {
990 ra_pages = arg->max_readahead / PAGE_SIZE;
991 if (arg->flags & FUSE_ASYNC_READ)
992 fc->async_read = 1;
993 if (!(arg->flags & FUSE_POSIX_LOCKS))
994 fc->no_lock = 1;
995 if (arg->minor >= 17) {
996 if (!(arg->flags & FUSE_FLOCK_LOCKS))
997 fc->no_flock = 1;
998 } else {
999 if (!(arg->flags & FUSE_POSIX_LOCKS))
1000 fc->no_flock = 1;
1001 }
1002 if (arg->flags & FUSE_ATOMIC_O_TRUNC)
1003 fc->atomic_o_trunc = 1;
1004 if (arg->minor >= 9) {
1005 /* LOOKUP has dependency on proto version */
1006 if (arg->flags & FUSE_EXPORT_SUPPORT)
1007 fc->export_support = 1;
1008 }
1009 if (arg->flags & FUSE_BIG_WRITES)
1010 fc->big_writes = 1;
1011 if (arg->flags & FUSE_DONT_MASK)
1012 fc->dont_mask = 1;
1013 if (arg->flags & FUSE_AUTO_INVAL_DATA)
1014 fc->auto_inval_data = 1;
1015 else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA)
1016 fc->explicit_inval_data = 1;
1017 if (arg->flags & FUSE_DO_READDIRPLUS) {
1018 fc->do_readdirplus = 1;
1019 if (arg->flags & FUSE_READDIRPLUS_AUTO)
1020 fc->readdirplus_auto = 1;
1021 }
1022 if (arg->flags & FUSE_ASYNC_DIO)
1023 fc->async_dio = 1;
1024 if (arg->flags & FUSE_WRITEBACK_CACHE)
1025 fc->writeback_cache = 1;
1026 if (arg->flags & FUSE_PARALLEL_DIROPS)
1027 fc->parallel_dirops = 1;
1028 if (arg->flags & FUSE_HANDLE_KILLPRIV)
1029 fc->handle_killpriv = 1;
1030 if (arg->time_gran && arg->time_gran <= 1000000000)
1031 fm->sb->s_time_gran = arg->time_gran;
1032 if ((arg->flags & FUSE_POSIX_ACL)) {
1033 fc->default_permissions = 1;
1034 fc->posix_acl = 1;
1035 fm->sb->s_xattr = fuse_acl_xattr_handlers;
1036 }
1037 if (arg->flags & FUSE_CACHE_SYMLINKS)
1038 fc->cache_symlinks = 1;
1039 if (arg->flags & FUSE_ABORT_ERROR)
1040 fc->abort_err = 1;
1041 if (arg->flags & FUSE_MAX_PAGES) {
1042 fc->max_pages =
1043 min_t(unsigned int, FUSE_MAX_MAX_PAGES,
1044 max_t(unsigned int, arg->max_pages, 1));
1045 }
1046 if (IS_ENABLED(CONFIG_FUSE_DAX) &&
1047 arg->flags & FUSE_MAP_ALIGNMENT &&
1048 !fuse_dax_check_alignment(fc, arg->map_alignment)) {
1049 ok = false;
1050 }
1051 if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) {
1052 fc->handle_killpriv_v2 = 1;
1053 fm->sb->s_flags |= SB_NOSEC;
1054 }
1055 } else {
1056 ra_pages = fc->max_read / PAGE_SIZE;
1057 fc->no_lock = 1;
1058 fc->no_flock = 1;
1059 }
1060
1061 fm->sb->s_bdi->ra_pages =
1062 min(fm->sb->s_bdi->ra_pages, ra_pages);
1063 fc->minor = arg->minor;
1064 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
1065 fc->max_write = max_t(unsigned, 4096, fc->max_write);
1066 fc->conn_init = 1;
1067 }
1068 kfree(ia);
1069
1070 if (!ok) {
1071 fc->conn_init = 0;
1072 fc->conn_error = 1;
1073 }
1074
1075 fuse_set_initialized(fc);
1076 wake_up_all(&fc->blocked_waitq);
1077 }
1078
1079 void fuse_send_init(struct fuse_mount *fm)
1080 {
1081 struct fuse_init_args *ia;
1082
1083 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL);
1084
1085 ia->in.major = FUSE_KERNEL_VERSION;
1086 ia->in.minor = FUSE_KERNEL_MINOR_VERSION;
1087 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE;
1088 ia->in.flags |=
1089 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
1090 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
1091 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
1092 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
1093 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
1094 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT |
1095 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL |
1096 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS |
1097 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA |
1098 FUSE_HANDLE_KILLPRIV_V2;
1099 #ifdef CONFIG_FUSE_DAX
1100 if (fm->fc->dax)
1101 ia->in.flags |= FUSE_MAP_ALIGNMENT;
1102 #endif
1103 if (fm->fc->auto_submounts)
1104 ia->in.flags |= FUSE_SUBMOUNTS;
1105
1106 ia->args.opcode = FUSE_INIT;
1107 ia->args.in_numargs = 1;
1108 ia->args.in_args[0].size = sizeof(ia->in);
1109 ia->args.in_args[0].value = &ia->in;
1110 ia->args.out_numargs = 1;
1111 /* Variable length argument used for backward compatibility
1112 with interface version < 7.5. Rest of init_out is zeroed
1113 by do_get_request(), so a short reply is not a problem */
1114 ia->args.out_argvar = true;
1115 ia->args.out_args[0].size = sizeof(ia->out);
1116 ia->args.out_args[0].value = &ia->out;
1117 ia->args.force = true;
1118 ia->args.nocreds = true;
1119 ia->args.end = process_init_reply;
1120
1121 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0)
1122 process_init_reply(fm, &ia->args, -ENOTCONN);
1123 }
1124 EXPORT_SYMBOL_GPL(fuse_send_init);
1125
1126 void fuse_free_conn(struct fuse_conn *fc)
1127 {
1128 WARN_ON(!list_empty(&fc->devices));
1129 kfree_rcu(fc, rcu);
1130 }
1131 EXPORT_SYMBOL_GPL(fuse_free_conn);
1132
1133 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
1134 {
1135 int err;
1136 char *suffix = "";
1137
1138 if (sb->s_bdev) {
1139 suffix = "-fuseblk";
1140 /*
1141 * sb->s_bdi points to blkdev's bdi however we want to redirect
1142 * it to our private bdi...
1143 */
1144 bdi_put(sb->s_bdi);
1145 sb->s_bdi = &noop_backing_dev_info;
1146 }
1147 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
1148 MINOR(fc->dev), suffix);
1149 if (err)
1150 return err;
1151
1152 /* fuse does it's own writeback accounting */
1153 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT;
1154 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT;
1155
1156 /*
1157 * For a single fuse filesystem use max 1% of dirty +
1158 * writeback threshold.
1159 *
1160 * This gives about 1M of write buffer for memory maps on a
1161 * machine with 1G and 10% dirty_ratio, which should be more
1162 * than enough.
1163 *
1164 * Privileged users can raise it by writing to
1165 *
1166 * /sys/class/bdi/<bdi>/max_ratio
1167 */
1168 bdi_set_max_ratio(sb->s_bdi, 1);
1169
1170 return 0;
1171 }
1172
1173 struct fuse_dev *fuse_dev_alloc(void)
1174 {
1175 struct fuse_dev *fud;
1176 struct list_head *pq;
1177
1178 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL);
1179 if (!fud)
1180 return NULL;
1181
1182 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL);
1183 if (!pq) {
1184 kfree(fud);
1185 return NULL;
1186 }
1187
1188 fud->pq.processing = pq;
1189 fuse_pqueue_init(&fud->pq);
1190
1191 return fud;
1192 }
1193 EXPORT_SYMBOL_GPL(fuse_dev_alloc);
1194
1195 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc)
1196 {
1197 fud->fc = fuse_conn_get(fc);
1198 spin_lock(&fc->lock);
1199 list_add_tail(&fud->entry, &fc->devices);
1200 spin_unlock(&fc->lock);
1201 }
1202 EXPORT_SYMBOL_GPL(fuse_dev_install);
1203
1204 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc)
1205 {
1206 struct fuse_dev *fud;
1207
1208 fud = fuse_dev_alloc();
1209 if (!fud)
1210 return NULL;
1211
1212 fuse_dev_install(fud, fc);
1213 return fud;
1214 }
1215 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install);
1216
1217 void fuse_dev_free(struct fuse_dev *fud)
1218 {
1219 struct fuse_conn *fc = fud->fc;
1220
1221 if (fc) {
1222 spin_lock(&fc->lock);
1223 list_del(&fud->entry);
1224 spin_unlock(&fc->lock);
1225
1226 fuse_conn_put(fc);
1227 }
1228 kfree(fud->pq.processing);
1229 kfree(fud);
1230 }
1231 EXPORT_SYMBOL_GPL(fuse_dev_free);
1232
1233 static void fuse_fill_attr_from_inode(struct fuse_attr *attr,
1234 const struct fuse_inode *fi)
1235 {
1236 *attr = (struct fuse_attr){
1237 .ino = fi->inode.i_ino,
1238 .size = fi->inode.i_size,
1239 .blocks = fi->inode.i_blocks,
1240 .atime = fi->inode.i_atime.tv_sec,
1241 .mtime = fi->inode.i_mtime.tv_sec,
1242 .ctime = fi->inode.i_ctime.tv_sec,
1243 .atimensec = fi->inode.i_atime.tv_nsec,
1244 .mtimensec = fi->inode.i_mtime.tv_nsec,
1245 .ctimensec = fi->inode.i_ctime.tv_nsec,
1246 .mode = fi->inode.i_mode,
1247 .nlink = fi->inode.i_nlink,
1248 .uid = fi->inode.i_uid.val,
1249 .gid = fi->inode.i_gid.val,
1250 .rdev = fi->inode.i_rdev,
1251 .blksize = 1u << fi->inode.i_blkbits,
1252 };
1253 }
1254
1255 static void fuse_sb_defaults(struct super_block *sb)
1256 {
1257 sb->s_magic = FUSE_SUPER_MAGIC;
1258 sb->s_op = &fuse_super_operations;
1259 sb->s_xattr = fuse_xattr_handlers;
1260 sb->s_maxbytes = MAX_LFS_FILESIZE;
1261 sb->s_time_gran = 1;
1262 sb->s_export_op = &fuse_export_operations;
1263 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE;
1264 if (sb->s_user_ns != &init_user_ns)
1265 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
1266 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
1267
1268 /*
1269 * If we are not in the initial user namespace posix
1270 * acls must be translated.
1271 */
1272 if (sb->s_user_ns != &init_user_ns)
1273 sb->s_xattr = fuse_no_acl_xattr_handlers;
1274 }
1275
1276 int fuse_fill_super_submount(struct super_block *sb,
1277 struct fuse_inode *parent_fi)
1278 {
1279 struct fuse_mount *fm = get_fuse_mount_super(sb);
1280 struct super_block *parent_sb = parent_fi->inode.i_sb;
1281 struct fuse_attr root_attr;
1282 struct inode *root;
1283
1284 fuse_sb_defaults(sb);
1285 fm->sb = sb;
1286
1287 WARN_ON(sb->s_bdi != &noop_backing_dev_info);
1288 sb->s_bdi = bdi_get(parent_sb->s_bdi);
1289
1290 sb->s_xattr = parent_sb->s_xattr;
1291 sb->s_time_gran = parent_sb->s_time_gran;
1292 sb->s_blocksize = parent_sb->s_blocksize;
1293 sb->s_blocksize_bits = parent_sb->s_blocksize_bits;
1294 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL);
1295 if (parent_sb->s_subtype && !sb->s_subtype)
1296 return -ENOMEM;
1297
1298 fuse_fill_attr_from_inode(&root_attr, parent_fi);
1299 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0);
1300 /*
1301 * This inode is just a duplicate, so it is not looked up and
1302 * its nlookup should not be incremented. fuse_iget() does
1303 * that, though, so undo it here.
1304 */
1305 get_fuse_inode(root)->nlookup--;
1306 sb->s_d_op = &fuse_dentry_operations;
1307 sb->s_root = d_make_root(root);
1308 if (!sb->s_root)
1309 return -ENOMEM;
1310
1311 return 0;
1312 }
1313
1314 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
1315 {
1316 struct fuse_dev *fud = NULL;
1317 struct fuse_mount *fm = get_fuse_mount_super(sb);
1318 struct fuse_conn *fc = fm->fc;
1319 struct inode *root;
1320 struct dentry *root_dentry;
1321 int err;
1322
1323 err = -EINVAL;
1324 if (sb->s_flags & SB_MANDLOCK)
1325 goto err;
1326
1327 fuse_sb_defaults(sb);
1328
1329 if (ctx->is_bdev) {
1330 #ifdef CONFIG_BLOCK
1331 err = -EINVAL;
1332 if (!sb_set_blocksize(sb, ctx->blksize))
1333 goto err;
1334 #endif
1335 } else {
1336 sb->s_blocksize = PAGE_SIZE;
1337 sb->s_blocksize_bits = PAGE_SHIFT;
1338 }
1339
1340 sb->s_subtype = ctx->subtype;
1341 ctx->subtype = NULL;
1342 if (IS_ENABLED(CONFIG_FUSE_DAX)) {
1343 err = fuse_dax_conn_alloc(fc, ctx->dax_dev);
1344 if (err)
1345 goto err;
1346 }
1347
1348 if (ctx->fudptr) {
1349 err = -ENOMEM;
1350 fud = fuse_dev_alloc_install(fc);
1351 if (!fud)
1352 goto err_free_dax;
1353 }
1354
1355 fc->dev = sb->s_dev;
1356 fm->sb = sb;
1357 err = fuse_bdi_init(fc, sb);
1358 if (err)
1359 goto err_dev_free;
1360
1361 /* Handle umasking inside the fuse code */
1362 if (sb->s_flags & SB_POSIXACL)
1363 fc->dont_mask = 1;
1364 sb->s_flags |= SB_POSIXACL;
1365
1366 fc->default_permissions = ctx->default_permissions;
1367 fc->allow_other = ctx->allow_other;
1368 fc->user_id = ctx->user_id;
1369 fc->group_id = ctx->group_id;
1370 fc->legacy_opts_show = ctx->legacy_opts_show;
1371 fc->max_read = max_t(unsigned int, 4096, ctx->max_read);
1372 fc->destroy = ctx->destroy;
1373 fc->no_control = ctx->no_control;
1374 fc->no_force_umount = ctx->no_force_umount;
1375
1376 err = -ENOMEM;
1377 root = fuse_get_root_inode(sb, ctx->rootmode);
1378 sb->s_d_op = &fuse_root_dentry_operations;
1379 root_dentry = d_make_root(root);
1380 if (!root_dentry)
1381 goto err_dev_free;
1382 /* Root dentry doesn't have .d_revalidate */
1383 sb->s_d_op = &fuse_dentry_operations;
1384
1385 mutex_lock(&fuse_mutex);
1386 err = -EINVAL;
1387 if (ctx->fudptr && *ctx->fudptr)
1388 goto err_unlock;
1389
1390 err = fuse_ctl_add_conn(fc);
1391 if (err)
1392 goto err_unlock;
1393
1394 list_add_tail(&fc->entry, &fuse_conn_list);
1395 sb->s_root = root_dentry;
1396 if (ctx->fudptr)
1397 *ctx->fudptr = fud;
1398 mutex_unlock(&fuse_mutex);
1399 return 0;
1400
1401 err_unlock:
1402 mutex_unlock(&fuse_mutex);
1403 dput(root_dentry);
1404 err_dev_free:
1405 if (fud)
1406 fuse_dev_free(fud);
1407 err_free_dax:
1408 if (IS_ENABLED(CONFIG_FUSE_DAX))
1409 fuse_dax_conn_free(fc);
1410 err:
1411 return err;
1412 }
1413 EXPORT_SYMBOL_GPL(fuse_fill_super_common);
1414
1415 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
1416 {
1417 struct fuse_fs_context *ctx = fsc->fs_private;
1418 struct file *file;
1419 int err;
1420 struct fuse_conn *fc;
1421 struct fuse_mount *fm;
1422
1423 err = -EINVAL;
1424 file = fget(ctx->fd);
1425 if (!file)
1426 goto err;
1427
1428 /*
1429 * Require mount to happen from the same user namespace which
1430 * opened /dev/fuse to prevent potential attacks.
1431 */
1432 if ((file->f_op != &fuse_dev_operations) ||
1433 (file->f_cred->user_ns != sb->s_user_ns))
1434 goto err_fput;
1435 ctx->fudptr = &file->private_data;
1436
1437 fc = kmalloc(sizeof(*fc), GFP_KERNEL);
1438 err = -ENOMEM;
1439 if (!fc)
1440 goto err_fput;
1441
1442 fm = kzalloc(sizeof(*fm), GFP_KERNEL);
1443 if (!fm) {
1444 kfree(fc);
1445 goto err_fput;
1446 }
1447
1448 fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
1449 fc->release = fuse_free_conn;
1450
1451 sb->s_fs_info = fm;
1452
1453 err = fuse_fill_super_common(sb, ctx);
1454 if (err)
1455 goto err_put_conn;
1456 /*
1457 * atomic_dec_and_test() in fput() provides the necessary
1458 * memory barrier for file->private_data to be visible on all
1459 * CPUs after this
1460 */
1461 fput(file);
1462 fuse_send_init(get_fuse_mount_super(sb));
1463 return 0;
1464
1465 err_put_conn:
1466 fuse_conn_put(fc);
1467 kfree(fm);
1468 sb->s_fs_info = NULL;
1469 err_fput:
1470 fput(file);
1471 err:
1472 return err;
1473 }
1474
1475 static int fuse_get_tree(struct fs_context *fc)
1476 {
1477 struct fuse_fs_context *ctx = fc->fs_private;
1478
1479 if (!ctx->fd_present || !ctx->rootmode_present ||
1480 !ctx->user_id_present || !ctx->group_id_present)
1481 return -EINVAL;
1482
1483 #ifdef CONFIG_BLOCK
1484 if (ctx->is_bdev)
1485 return get_tree_bdev(fc, fuse_fill_super);
1486 #endif
1487
1488 return get_tree_nodev(fc, fuse_fill_super);
1489 }
1490
1491 static const struct fs_context_operations fuse_context_ops = {
1492 .free = fuse_free_fc,
1493 .parse_param = fuse_parse_param,
1494 .reconfigure = fuse_reconfigure,
1495 .get_tree = fuse_get_tree,
1496 };
1497
1498 /*
1499 * Set up the filesystem mount context.
1500 */
1501 static int fuse_init_fs_context(struct fs_context *fc)
1502 {
1503 struct fuse_fs_context *ctx;
1504
1505 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
1506 if (!ctx)
1507 return -ENOMEM;
1508
1509 ctx->max_read = ~0;
1510 ctx->blksize = FUSE_DEFAULT_BLKSIZE;
1511 ctx->legacy_opts_show = true;
1512
1513 #ifdef CONFIG_BLOCK
1514 if (fc->fs_type == &fuseblk_fs_type) {
1515 ctx->is_bdev = true;
1516 ctx->destroy = true;
1517 }
1518 #endif
1519
1520 fc->fs_private = ctx;
1521 fc->ops = &fuse_context_ops;
1522 return 0;
1523 }
1524
1525 bool fuse_mount_remove(struct fuse_mount *fm)
1526 {
1527 struct fuse_conn *fc = fm->fc;
1528 bool last = false;
1529
1530 down_write(&fc->killsb);
1531 list_del_init(&fm->fc_entry);
1532 if (list_empty(&fc->mounts))
1533 last = true;
1534 up_write(&fc->killsb);
1535
1536 return last;
1537 }
1538 EXPORT_SYMBOL_GPL(fuse_mount_remove);
1539
1540 void fuse_conn_destroy(struct fuse_mount *fm)
1541 {
1542 struct fuse_conn *fc = fm->fc;
1543
1544 if (fc->destroy)
1545 fuse_send_destroy(fm);
1546
1547 fuse_abort_conn(fc);
1548 fuse_wait_aborted(fc);
1549
1550 if (!list_empty(&fc->entry)) {
1551 mutex_lock(&fuse_mutex);
1552 list_del(&fc->entry);
1553 fuse_ctl_remove_conn(fc);
1554 mutex_unlock(&fuse_mutex);
1555 }
1556 }
1557 EXPORT_SYMBOL_GPL(fuse_conn_destroy);
1558
1559 static void fuse_sb_destroy(struct super_block *sb)
1560 {
1561 struct fuse_mount *fm = get_fuse_mount_super(sb);
1562 bool last;
1563
1564 if (fm) {
1565 last = fuse_mount_remove(fm);
1566 if (last)
1567 fuse_conn_destroy(fm);
1568 }
1569 }
1570
1571 static void fuse_kill_sb_anon(struct super_block *sb)
1572 {
1573 fuse_sb_destroy(sb);
1574 kill_anon_super(sb);
1575 }
1576
1577 static struct file_system_type fuse_fs_type = {
1578 .owner = THIS_MODULE,
1579 .name = "fuse",
1580 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT,
1581 .init_fs_context = fuse_init_fs_context,
1582 .parameters = fuse_fs_parameters,
1583 .kill_sb = fuse_kill_sb_anon,
1584 };
1585 MODULE_ALIAS_FS("fuse");
1586
1587 #ifdef CONFIG_BLOCK
1588 static void fuse_kill_sb_blk(struct super_block *sb)
1589 {
1590 fuse_sb_destroy(sb);
1591 kill_block_super(sb);
1592 }
1593
1594 static struct file_system_type fuseblk_fs_type = {
1595 .owner = THIS_MODULE,
1596 .name = "fuseblk",
1597 .init_fs_context = fuse_init_fs_context,
1598 .parameters = fuse_fs_parameters,
1599 .kill_sb = fuse_kill_sb_blk,
1600 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
1601 };
1602 MODULE_ALIAS_FS("fuseblk");
1603
1604 static inline int register_fuseblk(void)
1605 {
1606 return register_filesystem(&fuseblk_fs_type);
1607 }
1608
1609 static inline void unregister_fuseblk(void)
1610 {
1611 unregister_filesystem(&fuseblk_fs_type);
1612 }
1613 #else
1614 static inline int register_fuseblk(void)
1615 {
1616 return 0;
1617 }
1618
1619 static inline void unregister_fuseblk(void)
1620 {
1621 }
1622 #endif
1623
1624 static void fuse_inode_init_once(void *foo)
1625 {
1626 struct inode *inode = foo;
1627
1628 inode_init_once(inode);
1629 }
1630
1631 static int __init fuse_fs_init(void)
1632 {
1633 int err;
1634
1635 fuse_inode_cachep = kmem_cache_create("fuse_inode",
1636 sizeof(struct fuse_inode), 0,
1637 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT,
1638 fuse_inode_init_once);
1639 err = -ENOMEM;
1640 if (!fuse_inode_cachep)
1641 goto out;
1642
1643 err = register_fuseblk();
1644 if (err)
1645 goto out2;
1646
1647 err = register_filesystem(&fuse_fs_type);
1648 if (err)
1649 goto out3;
1650
1651 return 0;
1652
1653 out3:
1654 unregister_fuseblk();
1655 out2:
1656 kmem_cache_destroy(fuse_inode_cachep);
1657 out:
1658 return err;
1659 }
1660
1661 static void fuse_fs_cleanup(void)
1662 {
1663 unregister_filesystem(&fuse_fs_type);
1664 unregister_fuseblk();
1665
1666 /*
1667 * Make sure all delayed rcu free inodes are flushed before we
1668 * destroy cache.
1669 */
1670 rcu_barrier();
1671 kmem_cache_destroy(fuse_inode_cachep);
1672 }
1673
1674 static struct kobject *fuse_kobj;
1675
1676 static int fuse_sysfs_init(void)
1677 {
1678 int err;
1679
1680 fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1681 if (!fuse_kobj) {
1682 err = -ENOMEM;
1683 goto out_err;
1684 }
1685
1686 err = sysfs_create_mount_point(fuse_kobj, "connections");
1687 if (err)
1688 goto out_fuse_unregister;
1689
1690 return 0;
1691
1692 out_fuse_unregister:
1693 kobject_put(fuse_kobj);
1694 out_err:
1695 return err;
1696 }
1697
1698 static void fuse_sysfs_cleanup(void)
1699 {
1700 sysfs_remove_mount_point(fuse_kobj, "connections");
1701 kobject_put(fuse_kobj);
1702 }
1703
1704 static int __init fuse_init(void)
1705 {
1706 int res;
1707
1708 pr_info("init (API version %i.%i)\n",
1709 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1710
1711 INIT_LIST_HEAD(&fuse_conn_list);
1712 res = fuse_fs_init();
1713 if (res)
1714 goto err;
1715
1716 res = fuse_dev_init();
1717 if (res)
1718 goto err_fs_cleanup;
1719
1720 res = fuse_sysfs_init();
1721 if (res)
1722 goto err_dev_cleanup;
1723
1724 res = fuse_ctl_init();
1725 if (res)
1726 goto err_sysfs_cleanup;
1727
1728 sanitize_global_limit(&max_user_bgreq);
1729 sanitize_global_limit(&max_user_congthresh);
1730
1731 return 0;
1732
1733 err_sysfs_cleanup:
1734 fuse_sysfs_cleanup();
1735 err_dev_cleanup:
1736 fuse_dev_cleanup();
1737 err_fs_cleanup:
1738 fuse_fs_cleanup();
1739 err:
1740 return res;
1741 }
1742
1743 static void __exit fuse_exit(void)
1744 {
1745 pr_debug("exit\n");
1746
1747 fuse_ctl_cleanup();
1748 fuse_sysfs_cleanup();
1749 fuse_fs_cleanup();
1750 fuse_dev_cleanup();
1751 }
1752
1753 module_init(fuse_init);
1754 module_exit(fuse_exit);
Linux with added FPC-III support