1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/slab.h> 13 #include <linux/file.h> 14 #include <linux/seq_file.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/fs_context.h> 19 #include <linux/fs_parser.h> 20 #include <linux/statfs.h> 21 #include <linux/random.h> 22 #include <linux/sched.h> 23 #include <linux/exportfs.h> 24 #include <linux/posix_acl.h> 25 #include <linux/pid_namespace.h> 26 #include <uapi/linux/magic.h> 27 28 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 29 MODULE_DESCRIPTION("Filesystem in Userspace"); 30 MODULE_LICENSE("GPL"); 31 32 static struct kmem_cache *fuse_inode_cachep; 33 struct list_head fuse_conn_list; 34 DEFINE_MUTEX(fuse_mutex); 35 36 static int set_global_limit(const char *val, const struct kernel_param *kp); 37 38 unsigned max_user_bgreq; 39 module_param_call(max_user_bgreq, set_global_limit, param_get_uint, 40 &max_user_bgreq, 0644); 41 __MODULE_PARM_TYPE(max_user_bgreq, "uint"); 42 MODULE_PARM_DESC(max_user_bgreq, 43 "Global limit for the maximum number of backgrounded requests an " 44 "unprivileged user can set"); 45 46 unsigned max_user_congthresh; 47 module_param_call(max_user_congthresh, set_global_limit, param_get_uint, 48 &max_user_congthresh, 0644); 49 __MODULE_PARM_TYPE(max_user_congthresh, "uint"); 50 MODULE_PARM_DESC(max_user_congthresh, 51 "Global limit for the maximum congestion threshold an " 52 "unprivileged user can set"); 53 54 #define FUSE_DEFAULT_BLKSIZE 512 55 56 /** Maximum number of outstanding background requests */ 57 #define FUSE_DEFAULT_MAX_BACKGROUND 12 58 59 /** Congestion starts at 75% of maximum */ 60 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) 61 62 #ifdef CONFIG_BLOCK 63 static struct file_system_type fuseblk_fs_type; 64 #endif 65 66 struct fuse_forget_link *fuse_alloc_forget(void) 67 { 68 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT); 69 } 70 71 static struct fuse_submount_lookup *fuse_alloc_submount_lookup(void) 72 { 73 struct fuse_submount_lookup *sl; 74 75 sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT); 76 if (!sl) 77 return NULL; 78 sl->forget = fuse_alloc_forget(); 79 if (!sl->forget) 80 goto out_free; 81 82 return sl; 83 84 out_free: 85 kfree(sl); 86 return NULL; 87 } 88 89 static struct inode *fuse_alloc_inode(struct super_block *sb) 90 { 91 struct fuse_inode *fi; 92 93 fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL); 94 if (!fi) 95 return NULL; 96 97 fi->i_time = 0; 98 fi->inval_mask = ~0; 99 fi->nodeid = 0; 100 fi->nlookup = 0; 101 fi->attr_version = 0; 102 fi->orig_ino = 0; 103 fi->state = 0; 104 fi->submount_lookup = NULL; 105 mutex_init(&fi->mutex); 106 spin_lock_init(&fi->lock); 107 fi->forget = fuse_alloc_forget(); 108 if (!fi->forget) 109 goto out_free; 110 111 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi)) 112 goto out_free_forget; 113 114 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 115 fuse_inode_backing_set(fi, NULL); 116 117 return &fi->inode; 118 119 out_free_forget: 120 kfree(fi->forget); 121 out_free: 122 kmem_cache_free(fuse_inode_cachep, fi); 123 return NULL; 124 } 125 126 static void fuse_free_inode(struct inode *inode) 127 { 128 struct fuse_inode *fi = get_fuse_inode(inode); 129 130 mutex_destroy(&fi->mutex); 131 kfree(fi->forget); 132 #ifdef CONFIG_FUSE_DAX 133 kfree(fi->dax); 134 #endif 135 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 136 fuse_backing_put(fuse_inode_backing(fi)); 137 138 kmem_cache_free(fuse_inode_cachep, fi); 139 } 140 141 static void fuse_cleanup_submount_lookup(struct fuse_conn *fc, 142 struct fuse_submount_lookup *sl) 143 { 144 if (!refcount_dec_and_test(&sl->count)) 145 return; 146 147 fuse_queue_forget(fc, sl->forget, sl->nodeid, 1); 148 sl->forget = NULL; 149 kfree(sl); 150 } 151 152 static void fuse_evict_inode(struct inode *inode) 153 { 154 struct fuse_inode *fi = get_fuse_inode(inode); 155 156 /* Will write inode on close/munmap and in all other dirtiers */ 157 WARN_ON(inode->i_state & I_DIRTY_INODE); 158 159 truncate_inode_pages_final(&inode->i_data); 160 clear_inode(inode); 161 if (inode->i_sb->s_flags & SB_ACTIVE) { 162 struct fuse_conn *fc = get_fuse_conn(inode); 163 164 if (FUSE_IS_DAX(inode)) 165 fuse_dax_inode_cleanup(inode); 166 if (fi->nlookup) { 167 fuse_queue_forget(fc, fi->forget, fi->nodeid, 168 fi->nlookup); 169 fi->forget = NULL; 170 } 171 172 if (fi->submount_lookup) { 173 fuse_cleanup_submount_lookup(fc, fi->submount_lookup); 174 fi->submount_lookup = NULL; 175 } 176 } 177 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) { 178 WARN_ON(fi->iocachectr != 0); 179 WARN_ON(!list_empty(&fi->write_files)); 180 WARN_ON(!list_empty(&fi->queued_writes)); 181 } 182 } 183 184 static int fuse_reconfigure(struct fs_context *fsc) 185 { 186 struct super_block *sb = fsc->root->d_sb; 187 188 sync_filesystem(sb); 189 if (fsc->sb_flags & SB_MANDLOCK) 190 return -EINVAL; 191 192 return 0; 193 } 194 195 /* 196 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down 197 * so that it will fit. 198 */ 199 static ino_t fuse_squash_ino(u64 ino64) 200 { 201 ino_t ino = (ino_t) ino64; 202 if (sizeof(ino_t) < sizeof(u64)) 203 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; 204 return ino; 205 } 206 207 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 208 struct fuse_statx *sx, 209 u64 attr_valid, u32 cache_mask) 210 { 211 struct fuse_conn *fc = get_fuse_conn(inode); 212 struct fuse_inode *fi = get_fuse_inode(inode); 213 214 lockdep_assert_held(&fi->lock); 215 216 fi->attr_version = atomic64_inc_return(&fc->attr_version); 217 fi->i_time = attr_valid; 218 /* Clear basic stats from invalid mask */ 219 set_mask_bits(&fi->inval_mask, STATX_BASIC_STATS, 0); 220 221 inode->i_ino = fuse_squash_ino(attr->ino); 222 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 223 set_nlink(inode, attr->nlink); 224 inode->i_uid = make_kuid(fc->user_ns, attr->uid); 225 inode->i_gid = make_kgid(fc->user_ns, attr->gid); 226 inode->i_blocks = attr->blocks; 227 228 /* Sanitize nsecs */ 229 attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1); 230 attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1); 231 attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1); 232 233 inode_set_atime(inode, attr->atime, attr->atimensec); 234 /* mtime from server may be stale due to local buffered write */ 235 if (!(cache_mask & STATX_MTIME)) { 236 inode_set_mtime(inode, attr->mtime, attr->mtimensec); 237 } 238 if (!(cache_mask & STATX_CTIME)) { 239 inode_set_ctime(inode, attr->ctime, attr->ctimensec); 240 } 241 if (sx) { 242 /* Sanitize nsecs */ 243 sx->btime.tv_nsec = 244 min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1); 245 246 /* 247 * Btime has been queried, cache is valid (whether or not btime 248 * is available or not) so clear STATX_BTIME from inval_mask. 249 * 250 * Availability of the btime attribute is indicated in 251 * FUSE_I_BTIME 252 */ 253 set_mask_bits(&fi->inval_mask, STATX_BTIME, 0); 254 if (sx->mask & STATX_BTIME) { 255 set_bit(FUSE_I_BTIME, &fi->state); 256 fi->i_btime.tv_sec = sx->btime.tv_sec; 257 fi->i_btime.tv_nsec = sx->btime.tv_nsec; 258 } 259 } 260 261 if (attr->blksize != 0) 262 inode->i_blkbits = ilog2(attr->blksize); 263 else 264 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 265 266 /* 267 * Don't set the sticky bit in i_mode, unless we want the VFS 268 * to check permissions. This prevents failures due to the 269 * check in may_delete(). 270 */ 271 fi->orig_i_mode = inode->i_mode; 272 if (!fc->default_permissions) 273 inode->i_mode &= ~S_ISVTX; 274 275 fi->orig_ino = attr->ino; 276 277 /* 278 * We are refreshing inode data and it is possible that another 279 * client set suid/sgid or security.capability xattr. So clear 280 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid 281 * was set or if security.capability xattr was set. But we don't 282 * know if security.capability has been set or not. So clear it 283 * anyway. Its less efficient but should be safe. 284 */ 285 inode->i_flags &= ~S_NOSEC; 286 } 287 288 u32 fuse_get_cache_mask(struct inode *inode) 289 { 290 struct fuse_conn *fc = get_fuse_conn(inode); 291 292 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) 293 return 0; 294 295 return STATX_MTIME | STATX_CTIME | STATX_SIZE; 296 } 297 298 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 299 struct fuse_statx *sx, 300 u64 attr_valid, u64 attr_version) 301 { 302 struct fuse_conn *fc = get_fuse_conn(inode); 303 struct fuse_inode *fi = get_fuse_inode(inode); 304 u32 cache_mask; 305 loff_t oldsize; 306 struct timespec64 old_mtime; 307 308 spin_lock(&fi->lock); 309 /* 310 * In case of writeback_cache enabled, writes update mtime, ctime and 311 * may update i_size. In these cases trust the cached value in the 312 * inode. 313 */ 314 cache_mask = fuse_get_cache_mask(inode); 315 if (cache_mask & STATX_SIZE) 316 attr->size = i_size_read(inode); 317 318 if (cache_mask & STATX_MTIME) { 319 attr->mtime = inode_get_mtime_sec(inode); 320 attr->mtimensec = inode_get_mtime_nsec(inode); 321 } 322 if (cache_mask & STATX_CTIME) { 323 attr->ctime = inode_get_ctime_sec(inode); 324 attr->ctimensec = inode_get_ctime_nsec(inode); 325 } 326 327 if ((attr_version != 0 && fi->attr_version > attr_version) || 328 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { 329 spin_unlock(&fi->lock); 330 return; 331 } 332 333 old_mtime = inode_get_mtime(inode); 334 fuse_change_attributes_common(inode, attr, sx, attr_valid, cache_mask); 335 336 oldsize = inode->i_size; 337 /* 338 * In case of writeback_cache enabled, the cached writes beyond EOF 339 * extend local i_size without keeping userspace server in sync. So, 340 * attr->size coming from server can be stale. We cannot trust it. 341 */ 342 if (!(cache_mask & STATX_SIZE)) 343 i_size_write(inode, attr->size); 344 spin_unlock(&fi->lock); 345 346 if (!cache_mask && S_ISREG(inode->i_mode)) { 347 bool inval = false; 348 349 if (oldsize != attr->size) { 350 truncate_pagecache(inode, attr->size); 351 if (!fc->explicit_inval_data) 352 inval = true; 353 } else if (fc->auto_inval_data) { 354 struct timespec64 new_mtime = { 355 .tv_sec = attr->mtime, 356 .tv_nsec = attr->mtimensec, 357 }; 358 359 /* 360 * Auto inval mode also checks and invalidates if mtime 361 * has changed. 362 */ 363 if (!timespec64_equal(&old_mtime, &new_mtime)) 364 inval = true; 365 } 366 367 if (inval) 368 invalidate_inode_pages2(inode->i_mapping); 369 } 370 371 if (IS_ENABLED(CONFIG_FUSE_DAX)) 372 fuse_dax_dontcache(inode, attr->flags); 373 } 374 375 static void fuse_init_submount_lookup(struct fuse_submount_lookup *sl, 376 u64 nodeid) 377 { 378 sl->nodeid = nodeid; 379 refcount_set(&sl->count, 1); 380 } 381 382 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr, 383 struct fuse_conn *fc) 384 { 385 inode->i_mode = attr->mode & S_IFMT; 386 inode->i_size = attr->size; 387 inode_set_mtime(inode, attr->mtime, attr->mtimensec); 388 inode_set_ctime(inode, attr->ctime, attr->ctimensec); 389 if (S_ISREG(inode->i_mode)) { 390 fuse_init_common(inode); 391 fuse_init_file_inode(inode, attr->flags); 392 } else if (S_ISDIR(inode->i_mode)) 393 fuse_init_dir(inode); 394 else if (S_ISLNK(inode->i_mode)) 395 fuse_init_symlink(inode); 396 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 397 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 398 fuse_init_common(inode); 399 init_special_inode(inode, inode->i_mode, 400 new_decode_dev(attr->rdev)); 401 } else 402 BUG(); 403 /* 404 * Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL 405 * so they see the exact same behavior as before. 406 */ 407 if (!fc->posix_acl) 408 inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE; 409 } 410 411 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 412 { 413 u64 nodeid = *(u64 *) _nodeidp; 414 if (get_node_id(inode) == nodeid) 415 return 1; 416 else 417 return 0; 418 } 419 420 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 421 { 422 u64 nodeid = *(u64 *) _nodeidp; 423 get_fuse_inode(inode)->nodeid = nodeid; 424 return 0; 425 } 426 427 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 428 int generation, struct fuse_attr *attr, 429 u64 attr_valid, u64 attr_version) 430 { 431 struct inode *inode; 432 struct fuse_inode *fi; 433 struct fuse_conn *fc = get_fuse_conn_super(sb); 434 435 /* 436 * Auto mount points get their node id from the submount root, which is 437 * not a unique identifier within this filesystem. 438 * 439 * To avoid conflicts, do not place submount points into the inode hash 440 * table. 441 */ 442 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) && 443 S_ISDIR(attr->mode)) { 444 struct fuse_inode *fi; 445 446 inode = new_inode(sb); 447 if (!inode) 448 return NULL; 449 450 fuse_init_inode(inode, attr, fc); 451 fi = get_fuse_inode(inode); 452 fi->nodeid = nodeid; 453 fi->submount_lookup = fuse_alloc_submount_lookup(); 454 if (!fi->submount_lookup) { 455 iput(inode); 456 return NULL; 457 } 458 /* Sets nlookup = 1 on fi->submount_lookup->nlookup */ 459 fuse_init_submount_lookup(fi->submount_lookup, nodeid); 460 inode->i_flags |= S_AUTOMOUNT; 461 goto done; 462 } 463 464 retry: 465 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 466 if (!inode) 467 return NULL; 468 469 if ((inode->i_state & I_NEW)) { 470 inode->i_flags |= S_NOATIME; 471 if (!fc->writeback_cache || !S_ISREG(attr->mode)) 472 inode->i_flags |= S_NOCMTIME; 473 inode->i_generation = generation; 474 fuse_init_inode(inode, attr, fc); 475 unlock_new_inode(inode); 476 } else if (fuse_stale_inode(inode, generation, attr)) { 477 /* nodeid was reused, any I/O on the old inode should fail */ 478 fuse_make_bad(inode); 479 if (inode != d_inode(sb->s_root)) { 480 remove_inode_hash(inode); 481 iput(inode); 482 goto retry; 483 } 484 } 485 fi = get_fuse_inode(inode); 486 spin_lock(&fi->lock); 487 fi->nlookup++; 488 spin_unlock(&fi->lock); 489 done: 490 fuse_change_attributes(inode, attr, NULL, attr_valid, attr_version); 491 492 return inode; 493 } 494 495 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid, 496 struct fuse_mount **fm) 497 { 498 struct fuse_mount *fm_iter; 499 struct inode *inode; 500 501 WARN_ON(!rwsem_is_locked(&fc->killsb)); 502 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) { 503 if (!fm_iter->sb) 504 continue; 505 506 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid); 507 if (inode) { 508 if (fm) 509 *fm = fm_iter; 510 return inode; 511 } 512 } 513 514 return NULL; 515 } 516 517 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid, 518 loff_t offset, loff_t len) 519 { 520 struct fuse_inode *fi; 521 struct inode *inode; 522 pgoff_t pg_start; 523 pgoff_t pg_end; 524 525 inode = fuse_ilookup(fc, nodeid, NULL); 526 if (!inode) 527 return -ENOENT; 528 529 fi = get_fuse_inode(inode); 530 spin_lock(&fi->lock); 531 fi->attr_version = atomic64_inc_return(&fc->attr_version); 532 spin_unlock(&fi->lock); 533 534 fuse_invalidate_attr(inode); 535 forget_all_cached_acls(inode); 536 if (offset >= 0) { 537 pg_start = offset >> PAGE_SHIFT; 538 if (len <= 0) 539 pg_end = -1; 540 else 541 pg_end = (offset + len - 1) >> PAGE_SHIFT; 542 invalidate_inode_pages2_range(inode->i_mapping, 543 pg_start, pg_end); 544 } 545 iput(inode); 546 return 0; 547 } 548 549 bool fuse_lock_inode(struct inode *inode) 550 { 551 bool locked = false; 552 553 if (!get_fuse_conn(inode)->parallel_dirops) { 554 mutex_lock(&get_fuse_inode(inode)->mutex); 555 locked = true; 556 } 557 558 return locked; 559 } 560 561 void fuse_unlock_inode(struct inode *inode, bool locked) 562 { 563 if (locked) 564 mutex_unlock(&get_fuse_inode(inode)->mutex); 565 } 566 567 static void fuse_umount_begin(struct super_block *sb) 568 { 569 struct fuse_conn *fc = get_fuse_conn_super(sb); 570 571 if (fc->no_force_umount) 572 return; 573 574 fuse_abort_conn(fc); 575 576 // Only retire block-device-based superblocks. 577 if (sb->s_bdev != NULL) 578 retire_super(sb); 579 } 580 581 static void fuse_send_destroy(struct fuse_mount *fm) 582 { 583 if (fm->fc->conn_init) { 584 FUSE_ARGS(args); 585 586 args.opcode = FUSE_DESTROY; 587 args.force = true; 588 args.nocreds = true; 589 fuse_simple_request(fm, &args); 590 } 591 } 592 593 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 594 { 595 stbuf->f_type = FUSE_SUPER_MAGIC; 596 stbuf->f_bsize = attr->bsize; 597 stbuf->f_frsize = attr->frsize; 598 stbuf->f_blocks = attr->blocks; 599 stbuf->f_bfree = attr->bfree; 600 stbuf->f_bavail = attr->bavail; 601 stbuf->f_files = attr->files; 602 stbuf->f_ffree = attr->ffree; 603 stbuf->f_namelen = attr->namelen; 604 /* fsid is left zero */ 605 } 606 607 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 608 { 609 struct super_block *sb = dentry->d_sb; 610 struct fuse_mount *fm = get_fuse_mount_super(sb); 611 FUSE_ARGS(args); 612 struct fuse_statfs_out outarg; 613 int err; 614 615 if (!fuse_allow_current_process(fm->fc)) { 616 buf->f_type = FUSE_SUPER_MAGIC; 617 return 0; 618 } 619 620 memset(&outarg, 0, sizeof(outarg)); 621 args.in_numargs = 0; 622 args.opcode = FUSE_STATFS; 623 args.nodeid = get_node_id(d_inode(dentry)); 624 args.out_numargs = 1; 625 args.out_args[0].size = sizeof(outarg); 626 args.out_args[0].value = &outarg; 627 err = fuse_simple_request(fm, &args); 628 if (!err) 629 convert_fuse_statfs(buf, &outarg.st); 630 return err; 631 } 632 633 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void) 634 { 635 struct fuse_sync_bucket *bucket; 636 637 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL); 638 if (bucket) { 639 init_waitqueue_head(&bucket->waitq); 640 /* Initial active count */ 641 atomic_set(&bucket->count, 1); 642 } 643 return bucket; 644 } 645 646 static void fuse_sync_fs_writes(struct fuse_conn *fc) 647 { 648 struct fuse_sync_bucket *bucket, *new_bucket; 649 int count; 650 651 new_bucket = fuse_sync_bucket_alloc(); 652 spin_lock(&fc->lock); 653 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 654 count = atomic_read(&bucket->count); 655 WARN_ON(count < 1); 656 /* No outstanding writes? */ 657 if (count == 1) { 658 spin_unlock(&fc->lock); 659 kfree(new_bucket); 660 return; 661 } 662 663 /* 664 * Completion of new bucket depends on completion of this bucket, so add 665 * one more count. 666 */ 667 atomic_inc(&new_bucket->count); 668 rcu_assign_pointer(fc->curr_bucket, new_bucket); 669 spin_unlock(&fc->lock); 670 /* 671 * Drop initial active count. At this point if all writes in this and 672 * ancestor buckets complete, the count will go to zero and this task 673 * will be woken up. 674 */ 675 atomic_dec(&bucket->count); 676 677 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0); 678 679 /* Drop temp count on descendant bucket */ 680 fuse_sync_bucket_dec(new_bucket); 681 kfree_rcu(bucket, rcu); 682 } 683 684 static int fuse_sync_fs(struct super_block *sb, int wait) 685 { 686 struct fuse_mount *fm = get_fuse_mount_super(sb); 687 struct fuse_conn *fc = fm->fc; 688 struct fuse_syncfs_in inarg; 689 FUSE_ARGS(args); 690 int err; 691 692 /* 693 * Userspace cannot handle the wait == 0 case. Avoid a 694 * gratuitous roundtrip. 695 */ 696 if (!wait) 697 return 0; 698 699 /* The filesystem is being unmounted. Nothing to do. */ 700 if (!sb->s_root) 701 return 0; 702 703 if (!fc->sync_fs) 704 return 0; 705 706 fuse_sync_fs_writes(fc); 707 708 memset(&inarg, 0, sizeof(inarg)); 709 args.in_numargs = 1; 710 args.in_args[0].size = sizeof(inarg); 711 args.in_args[0].value = &inarg; 712 args.opcode = FUSE_SYNCFS; 713 args.nodeid = get_node_id(sb->s_root->d_inode); 714 args.out_numargs = 0; 715 716 err = fuse_simple_request(fm, &args); 717 if (err == -ENOSYS) { 718 fc->sync_fs = 0; 719 err = 0; 720 } 721 722 return err; 723 } 724 725 enum { 726 OPT_SOURCE, 727 OPT_SUBTYPE, 728 OPT_FD, 729 OPT_ROOTMODE, 730 OPT_USER_ID, 731 OPT_GROUP_ID, 732 OPT_DEFAULT_PERMISSIONS, 733 OPT_ALLOW_OTHER, 734 OPT_MAX_READ, 735 OPT_BLKSIZE, 736 OPT_ERR 737 }; 738 739 static const struct fs_parameter_spec fuse_fs_parameters[] = { 740 fsparam_string ("source", OPT_SOURCE), 741 fsparam_u32 ("fd", OPT_FD), 742 fsparam_u32oct ("rootmode", OPT_ROOTMODE), 743 fsparam_uid ("user_id", OPT_USER_ID), 744 fsparam_gid ("group_id", OPT_GROUP_ID), 745 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS), 746 fsparam_flag ("allow_other", OPT_ALLOW_OTHER), 747 fsparam_u32 ("max_read", OPT_MAX_READ), 748 fsparam_u32 ("blksize", OPT_BLKSIZE), 749 fsparam_string ("subtype", OPT_SUBTYPE), 750 {} 751 }; 752 753 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param) 754 { 755 struct fs_parse_result result; 756 struct fuse_fs_context *ctx = fsc->fs_private; 757 int opt; 758 kuid_t kuid; 759 kgid_t kgid; 760 761 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { 762 /* 763 * Ignore options coming from mount(MS_REMOUNT) for backward 764 * compatibility. 765 */ 766 if (fsc->oldapi) 767 return 0; 768 769 return invalfc(fsc, "No changes allowed in reconfigure"); 770 } 771 772 opt = fs_parse(fsc, fuse_fs_parameters, param, &result); 773 if (opt < 0) 774 return opt; 775 776 switch (opt) { 777 case OPT_SOURCE: 778 if (fsc->source) 779 return invalfc(fsc, "Multiple sources specified"); 780 fsc->source = param->string; 781 param->string = NULL; 782 break; 783 784 case OPT_SUBTYPE: 785 if (ctx->subtype) 786 return invalfc(fsc, "Multiple subtypes specified"); 787 ctx->subtype = param->string; 788 param->string = NULL; 789 return 0; 790 791 case OPT_FD: 792 ctx->fd = result.uint_32; 793 ctx->fd_present = true; 794 break; 795 796 case OPT_ROOTMODE: 797 if (!fuse_valid_type(result.uint_32)) 798 return invalfc(fsc, "Invalid rootmode"); 799 ctx->rootmode = result.uint_32; 800 ctx->rootmode_present = true; 801 break; 802 803 case OPT_USER_ID: 804 kuid = result.uid; 805 /* 806 * The requested uid must be representable in the 807 * filesystem's idmapping. 808 */ 809 if (!kuid_has_mapping(fsc->user_ns, kuid)) 810 return invalfc(fsc, "Invalid user_id"); 811 ctx->user_id = kuid; 812 ctx->user_id_present = true; 813 break; 814 815 case OPT_GROUP_ID: 816 kgid = result.gid; 817 /* 818 * The requested gid must be representable in the 819 * filesystem's idmapping. 820 */ 821 if (!kgid_has_mapping(fsc->user_ns, kgid)) 822 return invalfc(fsc, "Invalid group_id"); 823 ctx->group_id = kgid; 824 ctx->group_id_present = true; 825 break; 826 827 case OPT_DEFAULT_PERMISSIONS: 828 ctx->default_permissions = true; 829 break; 830 831 case OPT_ALLOW_OTHER: 832 ctx->allow_other = true; 833 break; 834 835 case OPT_MAX_READ: 836 ctx->max_read = result.uint_32; 837 break; 838 839 case OPT_BLKSIZE: 840 if (!ctx->is_bdev) 841 return invalfc(fsc, "blksize only supported for fuseblk"); 842 ctx->blksize = result.uint_32; 843 break; 844 845 default: 846 return -EINVAL; 847 } 848 849 return 0; 850 } 851 852 static void fuse_free_fsc(struct fs_context *fsc) 853 { 854 struct fuse_fs_context *ctx = fsc->fs_private; 855 856 if (ctx) { 857 kfree(ctx->subtype); 858 kfree(ctx); 859 } 860 } 861 862 static int fuse_show_options(struct seq_file *m, struct dentry *root) 863 { 864 struct super_block *sb = root->d_sb; 865 struct fuse_conn *fc = get_fuse_conn_super(sb); 866 867 if (fc->legacy_opts_show) { 868 seq_printf(m, ",user_id=%u", 869 from_kuid_munged(fc->user_ns, fc->user_id)); 870 seq_printf(m, ",group_id=%u", 871 from_kgid_munged(fc->user_ns, fc->group_id)); 872 if (fc->default_permissions) 873 seq_puts(m, ",default_permissions"); 874 if (fc->allow_other) 875 seq_puts(m, ",allow_other"); 876 if (fc->max_read != ~0) 877 seq_printf(m, ",max_read=%u", fc->max_read); 878 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 879 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 880 } 881 #ifdef CONFIG_FUSE_DAX 882 if (fc->dax_mode == FUSE_DAX_ALWAYS) 883 seq_puts(m, ",dax=always"); 884 else if (fc->dax_mode == FUSE_DAX_NEVER) 885 seq_puts(m, ",dax=never"); 886 else if (fc->dax_mode == FUSE_DAX_INODE_USER) 887 seq_puts(m, ",dax=inode"); 888 #endif 889 890 return 0; 891 } 892 893 static void fuse_iqueue_init(struct fuse_iqueue *fiq, 894 const struct fuse_iqueue_ops *ops, 895 void *priv) 896 { 897 memset(fiq, 0, sizeof(struct fuse_iqueue)); 898 spin_lock_init(&fiq->lock); 899 init_waitqueue_head(&fiq->waitq); 900 INIT_LIST_HEAD(&fiq->pending); 901 INIT_LIST_HEAD(&fiq->interrupts); 902 fiq->forget_list_tail = &fiq->forget_list_head; 903 fiq->connected = 1; 904 fiq->ops = ops; 905 fiq->priv = priv; 906 } 907 908 static void fuse_pqueue_init(struct fuse_pqueue *fpq) 909 { 910 unsigned int i; 911 912 spin_lock_init(&fpq->lock); 913 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 914 INIT_LIST_HEAD(&fpq->processing[i]); 915 INIT_LIST_HEAD(&fpq->io); 916 fpq->connected = 1; 917 } 918 919 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, 920 struct user_namespace *user_ns, 921 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv) 922 { 923 memset(fc, 0, sizeof(*fc)); 924 spin_lock_init(&fc->lock); 925 spin_lock_init(&fc->bg_lock); 926 init_rwsem(&fc->killsb); 927 refcount_set(&fc->count, 1); 928 atomic_set(&fc->dev_count, 1); 929 init_waitqueue_head(&fc->blocked_waitq); 930 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv); 931 INIT_LIST_HEAD(&fc->bg_queue); 932 INIT_LIST_HEAD(&fc->entry); 933 INIT_LIST_HEAD(&fc->devices); 934 atomic_set(&fc->num_waiting, 0); 935 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 936 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 937 atomic64_set(&fc->khctr, 0); 938 fc->polled_files = RB_ROOT; 939 fc->blocked = 0; 940 fc->initialized = 0; 941 fc->connected = 1; 942 atomic64_set(&fc->attr_version, 1); 943 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 944 fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); 945 fc->user_ns = get_user_ns(user_ns); 946 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; 947 fc->max_pages_limit = FUSE_MAX_MAX_PAGES; 948 949 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 950 fuse_backing_files_init(fc); 951 952 INIT_LIST_HEAD(&fc->mounts); 953 list_add(&fm->fc_entry, &fc->mounts); 954 fm->fc = fc; 955 } 956 EXPORT_SYMBOL_GPL(fuse_conn_init); 957 958 static void delayed_release(struct rcu_head *p) 959 { 960 struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu); 961 962 put_user_ns(fc->user_ns); 963 fc->release(fc); 964 } 965 966 void fuse_conn_put(struct fuse_conn *fc) 967 { 968 if (refcount_dec_and_test(&fc->count)) { 969 struct fuse_iqueue *fiq = &fc->iq; 970 struct fuse_sync_bucket *bucket; 971 972 if (IS_ENABLED(CONFIG_FUSE_DAX)) 973 fuse_dax_conn_free(fc); 974 if (fiq->ops->release) 975 fiq->ops->release(fiq); 976 put_pid_ns(fc->pid_ns); 977 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 978 if (bucket) { 979 WARN_ON(atomic_read(&bucket->count) != 1); 980 kfree(bucket); 981 } 982 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 983 fuse_backing_files_free(fc); 984 call_rcu(&fc->rcu, delayed_release); 985 } 986 } 987 EXPORT_SYMBOL_GPL(fuse_conn_put); 988 989 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 990 { 991 refcount_inc(&fc->count); 992 return fc; 993 } 994 EXPORT_SYMBOL_GPL(fuse_conn_get); 995 996 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 997 { 998 struct fuse_attr attr; 999 memset(&attr, 0, sizeof(attr)); 1000 1001 attr.mode = mode; 1002 attr.ino = FUSE_ROOT_ID; 1003 attr.nlink = 1; 1004 return fuse_iget(sb, FUSE_ROOT_ID, 0, &attr, 0, 0); 1005 } 1006 1007 struct fuse_inode_handle { 1008 u64 nodeid; 1009 u32 generation; 1010 }; 1011 1012 static struct dentry *fuse_get_dentry(struct super_block *sb, 1013 struct fuse_inode_handle *handle) 1014 { 1015 struct fuse_conn *fc = get_fuse_conn_super(sb); 1016 struct inode *inode; 1017 struct dentry *entry; 1018 int err = -ESTALE; 1019 1020 if (handle->nodeid == 0) 1021 goto out_err; 1022 1023 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 1024 if (!inode) { 1025 struct fuse_entry_out outarg; 1026 const struct qstr name = QSTR_INIT(".", 1); 1027 1028 if (!fc->export_support) 1029 goto out_err; 1030 1031 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 1032 &inode); 1033 if (err && err != -ENOENT) 1034 goto out_err; 1035 if (err || !inode) { 1036 err = -ESTALE; 1037 goto out_err; 1038 } 1039 err = -EIO; 1040 if (get_node_id(inode) != handle->nodeid) 1041 goto out_iput; 1042 } 1043 err = -ESTALE; 1044 if (inode->i_generation != handle->generation) 1045 goto out_iput; 1046 1047 entry = d_obtain_alias(inode); 1048 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 1049 fuse_invalidate_entry_cache(entry); 1050 1051 return entry; 1052 1053 out_iput: 1054 iput(inode); 1055 out_err: 1056 return ERR_PTR(err); 1057 } 1058 1059 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 1060 struct inode *parent) 1061 { 1062 int len = parent ? 6 : 3; 1063 u64 nodeid; 1064 u32 generation; 1065 1066 if (*max_len < len) { 1067 *max_len = len; 1068 return FILEID_INVALID; 1069 } 1070 1071 nodeid = get_fuse_inode(inode)->nodeid; 1072 generation = inode->i_generation; 1073 1074 fh[0] = (u32)(nodeid >> 32); 1075 fh[1] = (u32)(nodeid & 0xffffffff); 1076 fh[2] = generation; 1077 1078 if (parent) { 1079 nodeid = get_fuse_inode(parent)->nodeid; 1080 generation = parent->i_generation; 1081 1082 fh[3] = (u32)(nodeid >> 32); 1083 fh[4] = (u32)(nodeid & 0xffffffff); 1084 fh[5] = generation; 1085 } 1086 1087 *max_len = len; 1088 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN; 1089 } 1090 1091 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 1092 struct fid *fid, int fh_len, int fh_type) 1093 { 1094 struct fuse_inode_handle handle; 1095 1096 if ((fh_type != FILEID_INO64_GEN && 1097 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3) 1098 return NULL; 1099 1100 handle.nodeid = (u64) fid->raw[0] << 32; 1101 handle.nodeid |= (u64) fid->raw[1]; 1102 handle.generation = fid->raw[2]; 1103 return fuse_get_dentry(sb, &handle); 1104 } 1105 1106 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 1107 struct fid *fid, int fh_len, int fh_type) 1108 { 1109 struct fuse_inode_handle parent; 1110 1111 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6) 1112 return NULL; 1113 1114 parent.nodeid = (u64) fid->raw[3] << 32; 1115 parent.nodeid |= (u64) fid->raw[4]; 1116 parent.generation = fid->raw[5]; 1117 return fuse_get_dentry(sb, &parent); 1118 } 1119 1120 static struct dentry *fuse_get_parent(struct dentry *child) 1121 { 1122 struct inode *child_inode = d_inode(child); 1123 struct fuse_conn *fc = get_fuse_conn(child_inode); 1124 struct inode *inode; 1125 struct dentry *parent; 1126 struct fuse_entry_out outarg; 1127 int err; 1128 1129 if (!fc->export_support) 1130 return ERR_PTR(-ESTALE); 1131 1132 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 1133 &dotdot_name, &outarg, &inode); 1134 if (err) { 1135 if (err == -ENOENT) 1136 return ERR_PTR(-ESTALE); 1137 return ERR_PTR(err); 1138 } 1139 1140 parent = d_obtain_alias(inode); 1141 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 1142 fuse_invalidate_entry_cache(parent); 1143 1144 return parent; 1145 } 1146 1147 /* only for fid encoding; no support for file handle */ 1148 static const struct export_operations fuse_export_fid_operations = { 1149 .encode_fh = fuse_encode_fh, 1150 }; 1151 1152 static const struct export_operations fuse_export_operations = { 1153 .fh_to_dentry = fuse_fh_to_dentry, 1154 .fh_to_parent = fuse_fh_to_parent, 1155 .encode_fh = fuse_encode_fh, 1156 .get_parent = fuse_get_parent, 1157 }; 1158 1159 static const struct super_operations fuse_super_operations = { 1160 .alloc_inode = fuse_alloc_inode, 1161 .free_inode = fuse_free_inode, 1162 .evict_inode = fuse_evict_inode, 1163 .write_inode = fuse_write_inode, 1164 .drop_inode = generic_delete_inode, 1165 .umount_begin = fuse_umount_begin, 1166 .statfs = fuse_statfs, 1167 .sync_fs = fuse_sync_fs, 1168 .show_options = fuse_show_options, 1169 }; 1170 1171 static void sanitize_global_limit(unsigned *limit) 1172 { 1173 /* 1174 * The default maximum number of async requests is calculated to consume 1175 * 1/2^13 of the total memory, assuming 392 bytes per request. 1176 */ 1177 if (*limit == 0) 1178 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392; 1179 1180 if (*limit >= 1 << 16) 1181 *limit = (1 << 16) - 1; 1182 } 1183 1184 static int set_global_limit(const char *val, const struct kernel_param *kp) 1185 { 1186 int rv; 1187 1188 rv = param_set_uint(val, kp); 1189 if (rv) 1190 return rv; 1191 1192 sanitize_global_limit((unsigned *)kp->arg); 1193 1194 return 0; 1195 } 1196 1197 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 1198 { 1199 int cap_sys_admin = capable(CAP_SYS_ADMIN); 1200 1201 if (arg->minor < 13) 1202 return; 1203 1204 sanitize_global_limit(&max_user_bgreq); 1205 sanitize_global_limit(&max_user_congthresh); 1206 1207 spin_lock(&fc->bg_lock); 1208 if (arg->max_background) { 1209 fc->max_background = arg->max_background; 1210 1211 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 1212 fc->max_background = max_user_bgreq; 1213 } 1214 if (arg->congestion_threshold) { 1215 fc->congestion_threshold = arg->congestion_threshold; 1216 1217 if (!cap_sys_admin && 1218 fc->congestion_threshold > max_user_congthresh) 1219 fc->congestion_threshold = max_user_congthresh; 1220 } 1221 spin_unlock(&fc->bg_lock); 1222 } 1223 1224 struct fuse_init_args { 1225 struct fuse_args args; 1226 struct fuse_init_in in; 1227 struct fuse_init_out out; 1228 }; 1229 1230 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, 1231 int error) 1232 { 1233 struct fuse_conn *fc = fm->fc; 1234 struct fuse_init_args *ia = container_of(args, typeof(*ia), args); 1235 struct fuse_init_out *arg = &ia->out; 1236 bool ok = true; 1237 1238 if (error || arg->major != FUSE_KERNEL_VERSION) 1239 ok = false; 1240 else { 1241 unsigned long ra_pages; 1242 1243 process_init_limits(fc, arg); 1244 1245 if (arg->minor >= 6) { 1246 u64 flags = arg->flags; 1247 1248 if (flags & FUSE_INIT_EXT) 1249 flags |= (u64) arg->flags2 << 32; 1250 1251 ra_pages = arg->max_readahead / PAGE_SIZE; 1252 if (flags & FUSE_ASYNC_READ) 1253 fc->async_read = 1; 1254 if (!(flags & FUSE_POSIX_LOCKS)) 1255 fc->no_lock = 1; 1256 if (arg->minor >= 17) { 1257 if (!(flags & FUSE_FLOCK_LOCKS)) 1258 fc->no_flock = 1; 1259 } else { 1260 if (!(flags & FUSE_POSIX_LOCKS)) 1261 fc->no_flock = 1; 1262 } 1263 if (flags & FUSE_ATOMIC_O_TRUNC) 1264 fc->atomic_o_trunc = 1; 1265 if (arg->minor >= 9) { 1266 /* LOOKUP has dependency on proto version */ 1267 if (flags & FUSE_EXPORT_SUPPORT) 1268 fc->export_support = 1; 1269 } 1270 if (flags & FUSE_BIG_WRITES) 1271 fc->big_writes = 1; 1272 if (flags & FUSE_DONT_MASK) 1273 fc->dont_mask = 1; 1274 if (flags & FUSE_AUTO_INVAL_DATA) 1275 fc->auto_inval_data = 1; 1276 else if (flags & FUSE_EXPLICIT_INVAL_DATA) 1277 fc->explicit_inval_data = 1; 1278 if (flags & FUSE_DO_READDIRPLUS) { 1279 fc->do_readdirplus = 1; 1280 if (flags & FUSE_READDIRPLUS_AUTO) 1281 fc->readdirplus_auto = 1; 1282 } 1283 if (flags & FUSE_ASYNC_DIO) 1284 fc->async_dio = 1; 1285 if (flags & FUSE_WRITEBACK_CACHE) 1286 fc->writeback_cache = 1; 1287 if (flags & FUSE_PARALLEL_DIROPS) 1288 fc->parallel_dirops = 1; 1289 if (flags & FUSE_HANDLE_KILLPRIV) 1290 fc->handle_killpriv = 1; 1291 if (arg->time_gran && arg->time_gran <= 1000000000) 1292 fm->sb->s_time_gran = arg->time_gran; 1293 if ((flags & FUSE_POSIX_ACL)) { 1294 fc->default_permissions = 1; 1295 fc->posix_acl = 1; 1296 } 1297 if (flags & FUSE_CACHE_SYMLINKS) 1298 fc->cache_symlinks = 1; 1299 if (flags & FUSE_ABORT_ERROR) 1300 fc->abort_err = 1; 1301 if (flags & FUSE_MAX_PAGES) { 1302 fc->max_pages = 1303 min_t(unsigned int, fc->max_pages_limit, 1304 max_t(unsigned int, arg->max_pages, 1)); 1305 } 1306 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1307 if (flags & FUSE_MAP_ALIGNMENT && 1308 !fuse_dax_check_alignment(fc, arg->map_alignment)) { 1309 ok = false; 1310 } 1311 if (flags & FUSE_HAS_INODE_DAX) 1312 fc->inode_dax = 1; 1313 } 1314 if (flags & FUSE_HANDLE_KILLPRIV_V2) { 1315 fc->handle_killpriv_v2 = 1; 1316 fm->sb->s_flags |= SB_NOSEC; 1317 } 1318 if (flags & FUSE_SETXATTR_EXT) 1319 fc->setxattr_ext = 1; 1320 if (flags & FUSE_SECURITY_CTX) 1321 fc->init_security = 1; 1322 if (flags & FUSE_CREATE_SUPP_GROUP) 1323 fc->create_supp_group = 1; 1324 if (flags & FUSE_DIRECT_IO_ALLOW_MMAP) 1325 fc->direct_io_allow_mmap = 1; 1326 /* 1327 * max_stack_depth is the max stack depth of FUSE fs, 1328 * so it has to be at least 1 to support passthrough 1329 * to backing files. 1330 * 1331 * with max_stack_depth > 1, the backing files can be 1332 * on a stacked fs (e.g. overlayfs) themselves and with 1333 * max_stack_depth == 1, FUSE fs can be stacked as the 1334 * underlying fs of a stacked fs (e.g. overlayfs). 1335 */ 1336 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) && 1337 (flags & FUSE_PASSTHROUGH) && 1338 arg->max_stack_depth > 0 && 1339 arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH) { 1340 fc->passthrough = 1; 1341 fc->max_stack_depth = arg->max_stack_depth; 1342 fm->sb->s_stack_depth = arg->max_stack_depth; 1343 } 1344 if (flags & FUSE_NO_EXPORT_SUPPORT) 1345 fm->sb->s_export_op = &fuse_export_fid_operations; 1346 } else { 1347 ra_pages = fc->max_read / PAGE_SIZE; 1348 fc->no_lock = 1; 1349 fc->no_flock = 1; 1350 } 1351 1352 fm->sb->s_bdi->ra_pages = 1353 min(fm->sb->s_bdi->ra_pages, ra_pages); 1354 fc->minor = arg->minor; 1355 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 1356 fc->max_write = max_t(unsigned, 4096, fc->max_write); 1357 fc->conn_init = 1; 1358 } 1359 kfree(ia); 1360 1361 if (!ok) { 1362 fc->conn_init = 0; 1363 fc->conn_error = 1; 1364 } 1365 1366 fuse_set_initialized(fc); 1367 wake_up_all(&fc->blocked_waitq); 1368 } 1369 1370 void fuse_send_init(struct fuse_mount *fm) 1371 { 1372 struct fuse_init_args *ia; 1373 u64 flags; 1374 1375 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL); 1376 1377 ia->in.major = FUSE_KERNEL_VERSION; 1378 ia->in.minor = FUSE_KERNEL_MINOR_VERSION; 1379 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE; 1380 flags = 1381 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 1382 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 1383 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 1384 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 1385 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 1386 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | 1387 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL | 1388 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS | 1389 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | 1390 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT | 1391 FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP | 1392 FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP | 1393 FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND; 1394 #ifdef CONFIG_FUSE_DAX 1395 if (fm->fc->dax) 1396 flags |= FUSE_MAP_ALIGNMENT; 1397 if (fuse_is_inode_dax_mode(fm->fc->dax_mode)) 1398 flags |= FUSE_HAS_INODE_DAX; 1399 #endif 1400 if (fm->fc->auto_submounts) 1401 flags |= FUSE_SUBMOUNTS; 1402 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 1403 flags |= FUSE_PASSTHROUGH; 1404 1405 ia->in.flags = flags; 1406 ia->in.flags2 = flags >> 32; 1407 1408 ia->args.opcode = FUSE_INIT; 1409 ia->args.in_numargs = 1; 1410 ia->args.in_args[0].size = sizeof(ia->in); 1411 ia->args.in_args[0].value = &ia->in; 1412 ia->args.out_numargs = 1; 1413 /* Variable length argument used for backward compatibility 1414 with interface version < 7.5. Rest of init_out is zeroed 1415 by do_get_request(), so a short reply is not a problem */ 1416 ia->args.out_argvar = true; 1417 ia->args.out_args[0].size = sizeof(ia->out); 1418 ia->args.out_args[0].value = &ia->out; 1419 ia->args.force = true; 1420 ia->args.nocreds = true; 1421 ia->args.end = process_init_reply; 1422 1423 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0) 1424 process_init_reply(fm, &ia->args, -ENOTCONN); 1425 } 1426 EXPORT_SYMBOL_GPL(fuse_send_init); 1427 1428 void fuse_free_conn(struct fuse_conn *fc) 1429 { 1430 WARN_ON(!list_empty(&fc->devices)); 1431 kfree(fc); 1432 } 1433 EXPORT_SYMBOL_GPL(fuse_free_conn); 1434 1435 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 1436 { 1437 int err; 1438 char *suffix = ""; 1439 1440 if (sb->s_bdev) { 1441 suffix = "-fuseblk"; 1442 /* 1443 * sb->s_bdi points to blkdev's bdi however we want to redirect 1444 * it to our private bdi... 1445 */ 1446 bdi_put(sb->s_bdi); 1447 sb->s_bdi = &noop_backing_dev_info; 1448 } 1449 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev), 1450 MINOR(fc->dev), suffix); 1451 if (err) 1452 return err; 1453 1454 /* fuse does it's own writeback accounting */ 1455 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT; 1456 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT; 1457 1458 /* 1459 * For a single fuse filesystem use max 1% of dirty + 1460 * writeback threshold. 1461 * 1462 * This gives about 1M of write buffer for memory maps on a 1463 * machine with 1G and 10% dirty_ratio, which should be more 1464 * than enough. 1465 * 1466 * Privileged users can raise it by writing to 1467 * 1468 * /sys/class/bdi/<bdi>/max_ratio 1469 */ 1470 bdi_set_max_ratio(sb->s_bdi, 1); 1471 1472 return 0; 1473 } 1474 1475 struct fuse_dev *fuse_dev_alloc(void) 1476 { 1477 struct fuse_dev *fud; 1478 struct list_head *pq; 1479 1480 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); 1481 if (!fud) 1482 return NULL; 1483 1484 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL); 1485 if (!pq) { 1486 kfree(fud); 1487 return NULL; 1488 } 1489 1490 fud->pq.processing = pq; 1491 fuse_pqueue_init(&fud->pq); 1492 1493 return fud; 1494 } 1495 EXPORT_SYMBOL_GPL(fuse_dev_alloc); 1496 1497 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) 1498 { 1499 fud->fc = fuse_conn_get(fc); 1500 spin_lock(&fc->lock); 1501 list_add_tail(&fud->entry, &fc->devices); 1502 spin_unlock(&fc->lock); 1503 } 1504 EXPORT_SYMBOL_GPL(fuse_dev_install); 1505 1506 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) 1507 { 1508 struct fuse_dev *fud; 1509 1510 fud = fuse_dev_alloc(); 1511 if (!fud) 1512 return NULL; 1513 1514 fuse_dev_install(fud, fc); 1515 return fud; 1516 } 1517 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); 1518 1519 void fuse_dev_free(struct fuse_dev *fud) 1520 { 1521 struct fuse_conn *fc = fud->fc; 1522 1523 if (fc) { 1524 spin_lock(&fc->lock); 1525 list_del(&fud->entry); 1526 spin_unlock(&fc->lock); 1527 1528 fuse_conn_put(fc); 1529 } 1530 kfree(fud->pq.processing); 1531 kfree(fud); 1532 } 1533 EXPORT_SYMBOL_GPL(fuse_dev_free); 1534 1535 static void fuse_fill_attr_from_inode(struct fuse_attr *attr, 1536 const struct fuse_inode *fi) 1537 { 1538 struct timespec64 atime = inode_get_atime(&fi->inode); 1539 struct timespec64 mtime = inode_get_mtime(&fi->inode); 1540 struct timespec64 ctime = inode_get_ctime(&fi->inode); 1541 1542 *attr = (struct fuse_attr){ 1543 .ino = fi->inode.i_ino, 1544 .size = fi->inode.i_size, 1545 .blocks = fi->inode.i_blocks, 1546 .atime = atime.tv_sec, 1547 .mtime = mtime.tv_sec, 1548 .ctime = ctime.tv_sec, 1549 .atimensec = atime.tv_nsec, 1550 .mtimensec = mtime.tv_nsec, 1551 .ctimensec = ctime.tv_nsec, 1552 .mode = fi->inode.i_mode, 1553 .nlink = fi->inode.i_nlink, 1554 .uid = __kuid_val(fi->inode.i_uid), 1555 .gid = __kgid_val(fi->inode.i_gid), 1556 .rdev = fi->inode.i_rdev, 1557 .blksize = 1u << fi->inode.i_blkbits, 1558 }; 1559 } 1560 1561 static void fuse_sb_defaults(struct super_block *sb) 1562 { 1563 sb->s_magic = FUSE_SUPER_MAGIC; 1564 sb->s_op = &fuse_super_operations; 1565 sb->s_xattr = fuse_xattr_handlers; 1566 sb->s_maxbytes = MAX_LFS_FILESIZE; 1567 sb->s_time_gran = 1; 1568 sb->s_export_op = &fuse_export_operations; 1569 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; 1570 if (sb->s_user_ns != &init_user_ns) 1571 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; 1572 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); 1573 } 1574 1575 static int fuse_fill_super_submount(struct super_block *sb, 1576 struct fuse_inode *parent_fi) 1577 { 1578 struct fuse_mount *fm = get_fuse_mount_super(sb); 1579 struct super_block *parent_sb = parent_fi->inode.i_sb; 1580 struct fuse_attr root_attr; 1581 struct inode *root; 1582 struct fuse_submount_lookup *sl; 1583 struct fuse_inode *fi; 1584 1585 fuse_sb_defaults(sb); 1586 fm->sb = sb; 1587 1588 WARN_ON(sb->s_bdi != &noop_backing_dev_info); 1589 sb->s_bdi = bdi_get(parent_sb->s_bdi); 1590 1591 sb->s_xattr = parent_sb->s_xattr; 1592 sb->s_export_op = parent_sb->s_export_op; 1593 sb->s_time_gran = parent_sb->s_time_gran; 1594 sb->s_blocksize = parent_sb->s_blocksize; 1595 sb->s_blocksize_bits = parent_sb->s_blocksize_bits; 1596 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL); 1597 if (parent_sb->s_subtype && !sb->s_subtype) 1598 return -ENOMEM; 1599 1600 fuse_fill_attr_from_inode(&root_attr, parent_fi); 1601 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0); 1602 /* 1603 * This inode is just a duplicate, so it is not looked up and 1604 * its nlookup should not be incremented. fuse_iget() does 1605 * that, though, so undo it here. 1606 */ 1607 fi = get_fuse_inode(root); 1608 fi->nlookup--; 1609 1610 sb->s_d_op = &fuse_dentry_operations; 1611 sb->s_root = d_make_root(root); 1612 if (!sb->s_root) 1613 return -ENOMEM; 1614 1615 /* 1616 * Grab the parent's submount_lookup pointer and take a 1617 * reference on the shared nlookup from the parent. This is to 1618 * prevent the last forget for this nodeid from getting 1619 * triggered until all users have finished with it. 1620 */ 1621 sl = parent_fi->submount_lookup; 1622 WARN_ON(!sl); 1623 if (sl) { 1624 refcount_inc(&sl->count); 1625 fi->submount_lookup = sl; 1626 } 1627 1628 return 0; 1629 } 1630 1631 /* Filesystem context private data holds the FUSE inode of the mount point */ 1632 static int fuse_get_tree_submount(struct fs_context *fsc) 1633 { 1634 struct fuse_mount *fm; 1635 struct fuse_inode *mp_fi = fsc->fs_private; 1636 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); 1637 struct super_block *sb; 1638 int err; 1639 1640 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); 1641 if (!fm) 1642 return -ENOMEM; 1643 1644 fm->fc = fuse_conn_get(fc); 1645 fsc->s_fs_info = fm; 1646 sb = sget_fc(fsc, NULL, set_anon_super_fc); 1647 if (fsc->s_fs_info) 1648 fuse_mount_destroy(fm); 1649 if (IS_ERR(sb)) 1650 return PTR_ERR(sb); 1651 1652 /* Initialize superblock, making @mp_fi its root */ 1653 err = fuse_fill_super_submount(sb, mp_fi); 1654 if (err) { 1655 deactivate_locked_super(sb); 1656 return err; 1657 } 1658 1659 down_write(&fc->killsb); 1660 list_add_tail(&fm->fc_entry, &fc->mounts); 1661 up_write(&fc->killsb); 1662 1663 sb->s_flags |= SB_ACTIVE; 1664 fsc->root = dget(sb->s_root); 1665 1666 return 0; 1667 } 1668 1669 static const struct fs_context_operations fuse_context_submount_ops = { 1670 .get_tree = fuse_get_tree_submount, 1671 }; 1672 1673 int fuse_init_fs_context_submount(struct fs_context *fsc) 1674 { 1675 fsc->ops = &fuse_context_submount_ops; 1676 return 0; 1677 } 1678 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); 1679 1680 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 1681 { 1682 struct fuse_dev *fud = NULL; 1683 struct fuse_mount *fm = get_fuse_mount_super(sb); 1684 struct fuse_conn *fc = fm->fc; 1685 struct inode *root; 1686 struct dentry *root_dentry; 1687 int err; 1688 1689 err = -EINVAL; 1690 if (sb->s_flags & SB_MANDLOCK) 1691 goto err; 1692 1693 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc()); 1694 fuse_sb_defaults(sb); 1695 1696 if (ctx->is_bdev) { 1697 #ifdef CONFIG_BLOCK 1698 err = -EINVAL; 1699 if (!sb_set_blocksize(sb, ctx->blksize)) 1700 goto err; 1701 #endif 1702 } else { 1703 sb->s_blocksize = PAGE_SIZE; 1704 sb->s_blocksize_bits = PAGE_SHIFT; 1705 } 1706 1707 sb->s_subtype = ctx->subtype; 1708 ctx->subtype = NULL; 1709 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1710 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev); 1711 if (err) 1712 goto err; 1713 } 1714 1715 if (ctx->fudptr) { 1716 err = -ENOMEM; 1717 fud = fuse_dev_alloc_install(fc); 1718 if (!fud) 1719 goto err_free_dax; 1720 } 1721 1722 fc->dev = sb->s_dev; 1723 fm->sb = sb; 1724 err = fuse_bdi_init(fc, sb); 1725 if (err) 1726 goto err_dev_free; 1727 1728 /* Handle umasking inside the fuse code */ 1729 if (sb->s_flags & SB_POSIXACL) 1730 fc->dont_mask = 1; 1731 sb->s_flags |= SB_POSIXACL; 1732 1733 fc->default_permissions = ctx->default_permissions; 1734 fc->allow_other = ctx->allow_other; 1735 fc->user_id = ctx->user_id; 1736 fc->group_id = ctx->group_id; 1737 fc->legacy_opts_show = ctx->legacy_opts_show; 1738 fc->max_read = max_t(unsigned int, 4096, ctx->max_read); 1739 fc->destroy = ctx->destroy; 1740 fc->no_control = ctx->no_control; 1741 fc->no_force_umount = ctx->no_force_umount; 1742 1743 err = -ENOMEM; 1744 root = fuse_get_root_inode(sb, ctx->rootmode); 1745 sb->s_d_op = &fuse_root_dentry_operations; 1746 root_dentry = d_make_root(root); 1747 if (!root_dentry) 1748 goto err_dev_free; 1749 /* Root dentry doesn't have .d_revalidate */ 1750 sb->s_d_op = &fuse_dentry_operations; 1751 1752 mutex_lock(&fuse_mutex); 1753 err = -EINVAL; 1754 if (ctx->fudptr && *ctx->fudptr) 1755 goto err_unlock; 1756 1757 err = fuse_ctl_add_conn(fc); 1758 if (err) 1759 goto err_unlock; 1760 1761 list_add_tail(&fc->entry, &fuse_conn_list); 1762 sb->s_root = root_dentry; 1763 if (ctx->fudptr) 1764 *ctx->fudptr = fud; 1765 mutex_unlock(&fuse_mutex); 1766 return 0; 1767 1768 err_unlock: 1769 mutex_unlock(&fuse_mutex); 1770 dput(root_dentry); 1771 err_dev_free: 1772 if (fud) 1773 fuse_dev_free(fud); 1774 err_free_dax: 1775 if (IS_ENABLED(CONFIG_FUSE_DAX)) 1776 fuse_dax_conn_free(fc); 1777 err: 1778 return err; 1779 } 1780 EXPORT_SYMBOL_GPL(fuse_fill_super_common); 1781 1782 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 1783 { 1784 struct fuse_fs_context *ctx = fsc->fs_private; 1785 int err; 1786 1787 if (!ctx->file || !ctx->rootmode_present || 1788 !ctx->user_id_present || !ctx->group_id_present) 1789 return -EINVAL; 1790 1791 /* 1792 * Require mount to happen from the same user namespace which 1793 * opened /dev/fuse to prevent potential attacks. 1794 */ 1795 if ((ctx->file->f_op != &fuse_dev_operations) || 1796 (ctx->file->f_cred->user_ns != sb->s_user_ns)) 1797 return -EINVAL; 1798 ctx->fudptr = &ctx->file->private_data; 1799 1800 err = fuse_fill_super_common(sb, ctx); 1801 if (err) 1802 return err; 1803 /* file->private_data shall be visible on all CPUs after this */ 1804 smp_mb(); 1805 fuse_send_init(get_fuse_mount_super(sb)); 1806 return 0; 1807 } 1808 1809 /* 1810 * This is the path where user supplied an already initialized fuse dev. In 1811 * this case never create a new super if the old one is gone. 1812 */ 1813 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc) 1814 { 1815 return -ENOTCONN; 1816 } 1817 1818 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc) 1819 { 1820 1821 return fsc->sget_key == get_fuse_conn_super(sb); 1822 } 1823 1824 static int fuse_get_tree(struct fs_context *fsc) 1825 { 1826 struct fuse_fs_context *ctx = fsc->fs_private; 1827 struct fuse_dev *fud; 1828 struct fuse_conn *fc; 1829 struct fuse_mount *fm; 1830 struct super_block *sb; 1831 int err; 1832 1833 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1834 if (!fc) 1835 return -ENOMEM; 1836 1837 fm = kzalloc(sizeof(*fm), GFP_KERNEL); 1838 if (!fm) { 1839 kfree(fc); 1840 return -ENOMEM; 1841 } 1842 1843 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL); 1844 fc->release = fuse_free_conn; 1845 1846 fsc->s_fs_info = fm; 1847 1848 if (ctx->fd_present) 1849 ctx->file = fget(ctx->fd); 1850 1851 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) { 1852 err = get_tree_bdev(fsc, fuse_fill_super); 1853 goto out; 1854 } 1855 /* 1856 * While block dev mount can be initialized with a dummy device fd 1857 * (found by device name), normal fuse mounts can't 1858 */ 1859 err = -EINVAL; 1860 if (!ctx->file) 1861 goto out; 1862 1863 /* 1864 * Allow creating a fuse mount with an already initialized fuse 1865 * connection 1866 */ 1867 fud = READ_ONCE(ctx->file->private_data); 1868 if (ctx->file->f_op == &fuse_dev_operations && fud) { 1869 fsc->sget_key = fud->fc; 1870 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super); 1871 err = PTR_ERR_OR_ZERO(sb); 1872 if (!IS_ERR(sb)) 1873 fsc->root = dget(sb->s_root); 1874 } else { 1875 err = get_tree_nodev(fsc, fuse_fill_super); 1876 } 1877 out: 1878 if (fsc->s_fs_info) 1879 fuse_mount_destroy(fm); 1880 if (ctx->file) 1881 fput(ctx->file); 1882 return err; 1883 } 1884 1885 static const struct fs_context_operations fuse_context_ops = { 1886 .free = fuse_free_fsc, 1887 .parse_param = fuse_parse_param, 1888 .reconfigure = fuse_reconfigure, 1889 .get_tree = fuse_get_tree, 1890 }; 1891 1892 /* 1893 * Set up the filesystem mount context. 1894 */ 1895 static int fuse_init_fs_context(struct fs_context *fsc) 1896 { 1897 struct fuse_fs_context *ctx; 1898 1899 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); 1900 if (!ctx) 1901 return -ENOMEM; 1902 1903 ctx->max_read = ~0; 1904 ctx->blksize = FUSE_DEFAULT_BLKSIZE; 1905 ctx->legacy_opts_show = true; 1906 1907 #ifdef CONFIG_BLOCK 1908 if (fsc->fs_type == &fuseblk_fs_type) { 1909 ctx->is_bdev = true; 1910 ctx->destroy = true; 1911 } 1912 #endif 1913 1914 fsc->fs_private = ctx; 1915 fsc->ops = &fuse_context_ops; 1916 return 0; 1917 } 1918 1919 bool fuse_mount_remove(struct fuse_mount *fm) 1920 { 1921 struct fuse_conn *fc = fm->fc; 1922 bool last = false; 1923 1924 down_write(&fc->killsb); 1925 list_del_init(&fm->fc_entry); 1926 if (list_empty(&fc->mounts)) 1927 last = true; 1928 up_write(&fc->killsb); 1929 1930 return last; 1931 } 1932 EXPORT_SYMBOL_GPL(fuse_mount_remove); 1933 1934 void fuse_conn_destroy(struct fuse_mount *fm) 1935 { 1936 struct fuse_conn *fc = fm->fc; 1937 1938 if (fc->destroy) 1939 fuse_send_destroy(fm); 1940 1941 fuse_abort_conn(fc); 1942 fuse_wait_aborted(fc); 1943 1944 if (!list_empty(&fc->entry)) { 1945 mutex_lock(&fuse_mutex); 1946 list_del(&fc->entry); 1947 fuse_ctl_remove_conn(fc); 1948 mutex_unlock(&fuse_mutex); 1949 } 1950 } 1951 EXPORT_SYMBOL_GPL(fuse_conn_destroy); 1952 1953 static void fuse_sb_destroy(struct super_block *sb) 1954 { 1955 struct fuse_mount *fm = get_fuse_mount_super(sb); 1956 bool last; 1957 1958 if (sb->s_root) { 1959 last = fuse_mount_remove(fm); 1960 if (last) 1961 fuse_conn_destroy(fm); 1962 } 1963 } 1964 1965 void fuse_mount_destroy(struct fuse_mount *fm) 1966 { 1967 fuse_conn_put(fm->fc); 1968 kfree_rcu(fm, rcu); 1969 } 1970 EXPORT_SYMBOL(fuse_mount_destroy); 1971 1972 static void fuse_kill_sb_anon(struct super_block *sb) 1973 { 1974 fuse_sb_destroy(sb); 1975 kill_anon_super(sb); 1976 fuse_mount_destroy(get_fuse_mount_super(sb)); 1977 } 1978 1979 static struct file_system_type fuse_fs_type = { 1980 .owner = THIS_MODULE, 1981 .name = "fuse", 1982 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, 1983 .init_fs_context = fuse_init_fs_context, 1984 .parameters = fuse_fs_parameters, 1985 .kill_sb = fuse_kill_sb_anon, 1986 }; 1987 MODULE_ALIAS_FS("fuse"); 1988 1989 #ifdef CONFIG_BLOCK 1990 static void fuse_kill_sb_blk(struct super_block *sb) 1991 { 1992 fuse_sb_destroy(sb); 1993 kill_block_super(sb); 1994 fuse_mount_destroy(get_fuse_mount_super(sb)); 1995 } 1996 1997 static struct file_system_type fuseblk_fs_type = { 1998 .owner = THIS_MODULE, 1999 .name = "fuseblk", 2000 .init_fs_context = fuse_init_fs_context, 2001 .parameters = fuse_fs_parameters, 2002 .kill_sb = fuse_kill_sb_blk, 2003 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 2004 }; 2005 MODULE_ALIAS_FS("fuseblk"); 2006 2007 static inline int register_fuseblk(void) 2008 { 2009 return register_filesystem(&fuseblk_fs_type); 2010 } 2011 2012 static inline void unregister_fuseblk(void) 2013 { 2014 unregister_filesystem(&fuseblk_fs_type); 2015 } 2016 #else 2017 static inline int register_fuseblk(void) 2018 { 2019 return 0; 2020 } 2021 2022 static inline void unregister_fuseblk(void) 2023 { 2024 } 2025 #endif 2026 2027 static void fuse_inode_init_once(void *foo) 2028 { 2029 struct inode *inode = foo; 2030 2031 inode_init_once(inode); 2032 } 2033 2034 static int __init fuse_fs_init(void) 2035 { 2036 int err; 2037 2038 fuse_inode_cachep = kmem_cache_create("fuse_inode", 2039 sizeof(struct fuse_inode), 0, 2040 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT, 2041 fuse_inode_init_once); 2042 err = -ENOMEM; 2043 if (!fuse_inode_cachep) 2044 goto out; 2045 2046 err = register_fuseblk(); 2047 if (err) 2048 goto out2; 2049 2050 err = register_filesystem(&fuse_fs_type); 2051 if (err) 2052 goto out3; 2053 2054 return 0; 2055 2056 out3: 2057 unregister_fuseblk(); 2058 out2: 2059 kmem_cache_destroy(fuse_inode_cachep); 2060 out: 2061 return err; 2062 } 2063 2064 static void fuse_fs_cleanup(void) 2065 { 2066 unregister_filesystem(&fuse_fs_type); 2067 unregister_fuseblk(); 2068 2069 /* 2070 * Make sure all delayed rcu free inodes are flushed before we 2071 * destroy cache. 2072 */ 2073 rcu_barrier(); 2074 kmem_cache_destroy(fuse_inode_cachep); 2075 } 2076 2077 static struct kobject *fuse_kobj; 2078 2079 static int fuse_sysfs_init(void) 2080 { 2081 int err; 2082 2083 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 2084 if (!fuse_kobj) { 2085 err = -ENOMEM; 2086 goto out_err; 2087 } 2088 2089 err = sysfs_create_mount_point(fuse_kobj, "connections"); 2090 if (err) 2091 goto out_fuse_unregister; 2092 2093 return 0; 2094 2095 out_fuse_unregister: 2096 kobject_put(fuse_kobj); 2097 out_err: 2098 return err; 2099 } 2100 2101 static void fuse_sysfs_cleanup(void) 2102 { 2103 sysfs_remove_mount_point(fuse_kobj, "connections"); 2104 kobject_put(fuse_kobj); 2105 } 2106 2107 static int __init fuse_init(void) 2108 { 2109 int res; 2110 2111 pr_info("init (API version %i.%i)\n", 2112 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 2113 2114 INIT_LIST_HEAD(&fuse_conn_list); 2115 res = fuse_fs_init(); 2116 if (res) 2117 goto err; 2118 2119 res = fuse_dev_init(); 2120 if (res) 2121 goto err_fs_cleanup; 2122 2123 res = fuse_sysfs_init(); 2124 if (res) 2125 goto err_dev_cleanup; 2126 2127 res = fuse_ctl_init(); 2128 if (res) 2129 goto err_sysfs_cleanup; 2130 2131 sanitize_global_limit(&max_user_bgreq); 2132 sanitize_global_limit(&max_user_congthresh); 2133 2134 return 0; 2135 2136 err_sysfs_cleanup: 2137 fuse_sysfs_cleanup(); 2138 err_dev_cleanup: 2139 fuse_dev_cleanup(); 2140 err_fs_cleanup: 2141 fuse_fs_cleanup(); 2142 err: 2143 return res; 2144 } 2145 2146 static void __exit fuse_exit(void) 2147 { 2148 pr_debug("exit\n"); 2149 2150 fuse_ctl_cleanup(); 2151 fuse_sysfs_cleanup(); 2152 fuse_fs_cleanup(); 2153 fuse_dev_cleanup(); 2154 } 2155 2156 module_init(fuse_init); 2157 module_exit(fuse_exit); 2158