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 #include "fuse_dev_i.h" 11 #include "dev_uring_i.h" 12 13 #include <linux/dax.h> 14 #include <linux/pagemap.h> 15 #include <linux/slab.h> 16 #include <linux/file.h> 17 #include <linux/seq_file.h> 18 #include <linux/init.h> 19 #include <linux/module.h> 20 #include <linux/moduleparam.h> 21 #include <linux/fs_context.h> 22 #include <linux/fs_parser.h> 23 #include <linux/statfs.h> 24 #include <linux/random.h> 25 #include <linux/sched.h> 26 #include <linux/exportfs.h> 27 #include <linux/posix_acl.h> 28 #include <linux/pid_namespace.h> 29 #include <uapi/linux/magic.h> 30 31 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 32 MODULE_DESCRIPTION("Filesystem in Userspace"); 33 MODULE_LICENSE("GPL"); 34 35 static struct kmem_cache *fuse_inode_cachep; 36 struct list_head fuse_conn_list; 37 DEFINE_MUTEX(fuse_mutex); 38 DECLARE_WAIT_QUEUE_HEAD(fuse_dev_waitq); 39 40 static int set_global_limit(const char *val, const struct kernel_param *kp); 41 42 unsigned int fuse_max_pages_limit = 256; 43 /* default is no timeout */ 44 unsigned int fuse_default_req_timeout; 45 unsigned int fuse_max_req_timeout; 46 47 unsigned int max_user_bgreq; 48 module_param_call(max_user_bgreq, set_global_limit, param_get_uint, 49 &max_user_bgreq, 0644); 50 __MODULE_PARM_TYPE(max_user_bgreq, "uint"); 51 MODULE_PARM_DESC(max_user_bgreq, 52 "Global limit for the maximum number of backgrounded requests an " 53 "unprivileged user can set"); 54 55 unsigned int max_user_congthresh; 56 module_param_call(max_user_congthresh, set_global_limit, param_get_uint, 57 &max_user_congthresh, 0644); 58 __MODULE_PARM_TYPE(max_user_congthresh, "uint"); 59 MODULE_PARM_DESC(max_user_congthresh, 60 "Global limit for the maximum congestion threshold an " 61 "unprivileged user can set"); 62 63 #define FUSE_DEFAULT_BLKSIZE 512 64 65 /** Maximum number of outstanding background requests */ 66 #define FUSE_DEFAULT_MAX_BACKGROUND 12 67 68 /** Congestion starts at 75% of maximum */ 69 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) 70 71 #ifdef CONFIG_BLOCK 72 static struct file_system_type fuseblk_fs_type; 73 #endif 74 75 struct fuse_forget_link *fuse_alloc_forget(void) 76 { 77 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT); 78 } 79 80 static struct fuse_submount_lookup *fuse_alloc_submount_lookup(void) 81 { 82 struct fuse_submount_lookup *sl; 83 84 sl = kzalloc(sizeof(struct fuse_submount_lookup), GFP_KERNEL_ACCOUNT); 85 if (!sl) 86 return NULL; 87 sl->forget = fuse_alloc_forget(); 88 if (!sl->forget) 89 goto out_free; 90 91 return sl; 92 93 out_free: 94 kfree(sl); 95 return NULL; 96 } 97 98 static struct inode *fuse_alloc_inode(struct super_block *sb) 99 { 100 struct fuse_inode *fi; 101 102 fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL); 103 if (!fi) 104 return NULL; 105 106 /* Initialize private data (i.e. everything except fi->inode) */ 107 BUILD_BUG_ON(offsetof(struct fuse_inode, inode) != 0); 108 memset((void *) fi + sizeof(fi->inode), 0, sizeof(*fi) - sizeof(fi->inode)); 109 110 fi->inval_mask = ~0; 111 mutex_init(&fi->mutex); 112 spin_lock_init(&fi->lock); 113 fi->forget = fuse_alloc_forget(); 114 if (!fi->forget) 115 goto out_free; 116 117 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi)) 118 goto out_free_forget; 119 120 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 121 fuse_inode_backing_set(fi, NULL); 122 123 return &fi->inode; 124 125 out_free_forget: 126 kfree(fi->forget); 127 out_free: 128 kmem_cache_free(fuse_inode_cachep, fi); 129 return NULL; 130 } 131 132 static void fuse_free_inode(struct inode *inode) 133 { 134 struct fuse_inode *fi = get_fuse_inode(inode); 135 136 mutex_destroy(&fi->mutex); 137 kfree(fi->forget); 138 #ifdef CONFIG_FUSE_DAX 139 kfree(fi->dax); 140 #endif 141 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 142 fuse_backing_put(fuse_inode_backing(fi)); 143 144 kmem_cache_free(fuse_inode_cachep, fi); 145 } 146 147 static void fuse_cleanup_submount_lookup(struct fuse_conn *fc, 148 struct fuse_submount_lookup *sl) 149 { 150 if (!refcount_dec_and_test(&sl->count)) 151 return; 152 153 fuse_queue_forget(fc, sl->forget, sl->nodeid, 1); 154 sl->forget = NULL; 155 kfree(sl); 156 } 157 158 static void fuse_evict_inode(struct inode *inode) 159 { 160 struct fuse_inode *fi = get_fuse_inode(inode); 161 162 /* Will write inode on close/munmap and in all other dirtiers */ 163 WARN_ON(inode_state_read_once(inode) & I_DIRTY_INODE); 164 165 if (FUSE_IS_DAX(inode)) 166 dax_break_layout_final(inode); 167 168 truncate_inode_pages_final(&inode->i_data); 169 clear_inode(inode); 170 if (inode->i_sb->s_flags & SB_ACTIVE) { 171 struct fuse_conn *fc = get_fuse_conn(inode); 172 173 if (FUSE_IS_DAX(inode)) 174 fuse_dax_inode_cleanup(inode); 175 if (fi->nlookup) { 176 fuse_queue_forget(fc, fi->forget, fi->nodeid, 177 fi->nlookup); 178 fi->forget = NULL; 179 } 180 181 if (fi->submount_lookup) { 182 fuse_cleanup_submount_lookup(fc, fi->submount_lookup); 183 fi->submount_lookup = NULL; 184 } 185 /* 186 * Evict of non-deleted inode may race with outstanding 187 * LOOKUP/READDIRPLUS requests and result in inconsistency when 188 * the request finishes. Deal with that here by bumping a 189 * counter that can be compared to the starting value. 190 */ 191 if (inode->i_nlink > 0) 192 atomic64_inc(&fc->evict_ctr); 193 } 194 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) { 195 WARN_ON(fi->iocachectr != 0); 196 WARN_ON(!list_empty(&fi->write_files)); 197 WARN_ON(!list_empty(&fi->queued_writes)); 198 } 199 } 200 201 static int fuse_reconfigure(struct fs_context *fsc) 202 { 203 struct super_block *sb = fsc->root->d_sb; 204 205 sync_filesystem(sb); 206 if (fsc->sb_flags & SB_MANDLOCK) 207 return -EINVAL; 208 209 return 0; 210 } 211 212 /* 213 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down 214 * so that it will fit. 215 */ 216 static ino_t fuse_squash_ino(u64 ino64) 217 { 218 ino_t ino = (ino_t) ino64; 219 if (sizeof(ino_t) < sizeof(u64)) 220 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; 221 return ino; 222 } 223 224 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 225 struct fuse_statx *sx, 226 u64 attr_valid, u32 cache_mask, 227 u64 evict_ctr) 228 { 229 struct fuse_conn *fc = get_fuse_conn(inode); 230 struct fuse_inode *fi = get_fuse_inode(inode); 231 232 lockdep_assert_held(&fi->lock); 233 234 /* 235 * Clear basic stats from invalid mask. 236 * 237 * Don't do this if this is coming from a fuse_iget() call and there 238 * might have been a racing evict which would've invalidated the result 239 * if the attr_version would've been preserved. 240 * 241 * !evict_ctr -> this is create 242 * fi->attr_version != 0 -> this is not a new inode 243 * evict_ctr == fuse_get_evict_ctr() -> no evicts while during request 244 */ 245 if (!evict_ctr || fi->attr_version || evict_ctr == fuse_get_evict_ctr(fc)) 246 set_mask_bits(&fi->inval_mask, STATX_BASIC_STATS, 0); 247 248 fi->attr_version = atomic64_inc_return(&fc->attr_version); 249 fi->i_time = attr_valid; 250 251 inode->i_ino = fuse_squash_ino(attr->ino); 252 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 253 set_nlink(inode, attr->nlink); 254 inode->i_uid = make_kuid(fc->user_ns, attr->uid); 255 inode->i_gid = make_kgid(fc->user_ns, attr->gid); 256 inode->i_blocks = attr->blocks; 257 258 /* Sanitize nsecs */ 259 attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1); 260 attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1); 261 attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1); 262 263 inode_set_atime(inode, attr->atime, attr->atimensec); 264 /* mtime from server may be stale due to local buffered write */ 265 if (!(cache_mask & STATX_MTIME)) { 266 inode_set_mtime(inode, attr->mtime, attr->mtimensec); 267 } 268 if (!(cache_mask & STATX_CTIME)) { 269 inode_set_ctime(inode, attr->ctime, attr->ctimensec); 270 } 271 if (sx) { 272 /* Sanitize nsecs */ 273 sx->btime.tv_nsec = 274 min_t(u32, sx->btime.tv_nsec, NSEC_PER_SEC - 1); 275 276 /* 277 * Btime has been queried, cache is valid (whether or not btime 278 * is available or not) so clear STATX_BTIME from inval_mask. 279 * 280 * Availability of the btime attribute is indicated in 281 * FUSE_I_BTIME 282 */ 283 set_mask_bits(&fi->inval_mask, STATX_BTIME, 0); 284 if (sx->mask & STATX_BTIME) { 285 set_bit(FUSE_I_BTIME, &fi->state); 286 fi->i_btime.tv_sec = sx->btime.tv_sec; 287 fi->i_btime.tv_nsec = sx->btime.tv_nsec; 288 } 289 } 290 291 if (attr->blksize) 292 fi->cached_i_blkbits = ilog2(attr->blksize); 293 else 294 fi->cached_i_blkbits = inode->i_sb->s_blocksize_bits; 295 296 /* 297 * Don't set the sticky bit in i_mode, unless we want the VFS 298 * to check permissions. This prevents failures due to the 299 * check in may_delete(). 300 */ 301 fi->orig_i_mode = inode->i_mode; 302 if (!fc->default_permissions) 303 inode->i_mode &= ~S_ISVTX; 304 305 fi->orig_ino = attr->ino; 306 307 /* 308 * We are refreshing inode data and it is possible that another 309 * client set suid/sgid or security.capability xattr. So clear 310 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid 311 * was set or if security.capability xattr was set. But we don't 312 * know if security.capability has been set or not. So clear it 313 * anyway. Its less efficient but should be safe. 314 */ 315 inode->i_flags &= ~S_NOSEC; 316 } 317 318 u32 fuse_get_cache_mask(struct inode *inode) 319 { 320 struct fuse_conn *fc = get_fuse_conn(inode); 321 322 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) 323 return 0; 324 325 return STATX_MTIME | STATX_CTIME | STATX_SIZE; 326 } 327 328 static void fuse_change_attributes_i(struct inode *inode, struct fuse_attr *attr, 329 struct fuse_statx *sx, u64 attr_valid, 330 u64 attr_version, u64 evict_ctr) 331 { 332 struct fuse_conn *fc = get_fuse_conn(inode); 333 struct fuse_inode *fi = get_fuse_inode(inode); 334 u32 cache_mask; 335 loff_t oldsize; 336 struct timespec64 old_mtime; 337 338 spin_lock(&fi->lock); 339 /* 340 * In case of writeback_cache enabled, writes update mtime, ctime and 341 * may update i_size. In these cases trust the cached value in the 342 * inode. 343 */ 344 cache_mask = fuse_get_cache_mask(inode); 345 if (cache_mask & STATX_SIZE) 346 attr->size = i_size_read(inode); 347 348 if (cache_mask & STATX_MTIME) { 349 attr->mtime = inode_get_mtime_sec(inode); 350 attr->mtimensec = inode_get_mtime_nsec(inode); 351 } 352 if (cache_mask & STATX_CTIME) { 353 attr->ctime = inode_get_ctime_sec(inode); 354 attr->ctimensec = inode_get_ctime_nsec(inode); 355 } 356 357 if ((attr_version != 0 && fi->attr_version > attr_version) || 358 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { 359 spin_unlock(&fi->lock); 360 return; 361 } 362 363 old_mtime = inode_get_mtime(inode); 364 fuse_change_attributes_common(inode, attr, sx, attr_valid, cache_mask, 365 evict_ctr); 366 367 oldsize = inode->i_size; 368 /* 369 * In case of writeback_cache enabled, the cached writes beyond EOF 370 * extend local i_size without keeping userspace server in sync. So, 371 * attr->size coming from server can be stale. We cannot trust it. 372 */ 373 if (!(cache_mask & STATX_SIZE)) 374 i_size_write(inode, attr->size); 375 spin_unlock(&fi->lock); 376 377 if (!cache_mask && S_ISREG(inode->i_mode)) { 378 bool inval = false; 379 380 if (oldsize != attr->size) { 381 truncate_pagecache(inode, attr->size); 382 if (!fc->explicit_inval_data) 383 inval = true; 384 } else if (fc->auto_inval_data) { 385 struct timespec64 new_mtime = { 386 .tv_sec = attr->mtime, 387 .tv_nsec = attr->mtimensec, 388 }; 389 390 /* 391 * Auto inval mode also checks and invalidates if mtime 392 * has changed. 393 */ 394 if (!timespec64_equal(&old_mtime, &new_mtime)) 395 inval = true; 396 } 397 398 if (inval) 399 invalidate_inode_pages2(inode->i_mapping); 400 } 401 402 if (IS_ENABLED(CONFIG_FUSE_DAX)) 403 fuse_dax_dontcache(inode, attr->flags); 404 } 405 406 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 407 struct fuse_statx *sx, u64 attr_valid, 408 u64 attr_version) 409 { 410 fuse_change_attributes_i(inode, attr, sx, attr_valid, attr_version, 0); 411 } 412 413 static void fuse_init_submount_lookup(struct fuse_submount_lookup *sl, 414 u64 nodeid) 415 { 416 sl->nodeid = nodeid; 417 refcount_set(&sl->count, 1); 418 } 419 420 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr, 421 struct fuse_conn *fc) 422 { 423 inode->i_mode = attr->mode & S_IFMT; 424 inode->i_size = attr->size; 425 inode_set_mtime(inode, attr->mtime, attr->mtimensec); 426 inode_set_ctime(inode, attr->ctime, attr->ctimensec); 427 if (S_ISREG(inode->i_mode)) { 428 fuse_init_common(inode); 429 fuse_init_file_inode(inode, attr->flags); 430 } else if (S_ISDIR(inode->i_mode)) 431 fuse_init_dir(inode); 432 else if (S_ISLNK(inode->i_mode)) 433 fuse_init_symlink(inode); 434 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 435 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 436 fuse_init_common(inode); 437 init_special_inode(inode, inode->i_mode, 438 new_decode_dev(attr->rdev)); 439 } else 440 BUG(); 441 /* 442 * Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL 443 * so they see the exact same behavior as before. 444 */ 445 if (!fc->posix_acl) 446 inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE; 447 } 448 449 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 450 { 451 u64 nodeid = *(u64 *) _nodeidp; 452 if (get_node_id(inode) == nodeid) 453 return 1; 454 else 455 return 0; 456 } 457 458 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 459 { 460 u64 nodeid = *(u64 *) _nodeidp; 461 get_fuse_inode(inode)->nodeid = nodeid; 462 return 0; 463 } 464 465 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 466 int generation, struct fuse_attr *attr, 467 u64 attr_valid, u64 attr_version, 468 u64 evict_ctr) 469 { 470 struct inode *inode; 471 struct fuse_inode *fi; 472 struct fuse_conn *fc = get_fuse_conn_super(sb); 473 474 /* 475 * Auto mount points get their node id from the submount root, which is 476 * not a unique identifier within this filesystem. 477 * 478 * To avoid conflicts, do not place submount points into the inode hash 479 * table. 480 */ 481 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) && 482 S_ISDIR(attr->mode)) { 483 struct fuse_inode *fi; 484 485 inode = new_inode(sb); 486 if (!inode) 487 return NULL; 488 489 fuse_init_inode(inode, attr, fc); 490 fi = get_fuse_inode(inode); 491 fi->nodeid = nodeid; 492 fi->submount_lookup = fuse_alloc_submount_lookup(); 493 if (!fi->submount_lookup) { 494 iput(inode); 495 return NULL; 496 } 497 /* Sets nlookup = 1 on fi->submount_lookup->nlookup */ 498 fuse_init_submount_lookup(fi->submount_lookup, nodeid); 499 inode->i_flags |= S_AUTOMOUNT; 500 goto done; 501 } 502 503 retry: 504 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 505 if (!inode) 506 return NULL; 507 508 if ((inode_state_read_once(inode) & I_NEW)) { 509 inode->i_flags |= S_NOATIME; 510 if (!fc->writeback_cache || !S_ISREG(attr->mode)) 511 inode->i_flags |= S_NOCMTIME; 512 inode->i_generation = generation; 513 fuse_init_inode(inode, attr, fc); 514 unlock_new_inode(inode); 515 } else if (fuse_stale_inode(inode, generation, attr)) { 516 /* nodeid was reused, any I/O on the old inode should fail */ 517 fuse_make_bad(inode); 518 if (inode != d_inode(sb->s_root)) { 519 remove_inode_hash(inode); 520 iput(inode); 521 goto retry; 522 } 523 } 524 fi = get_fuse_inode(inode); 525 spin_lock(&fi->lock); 526 fi->nlookup++; 527 spin_unlock(&fi->lock); 528 done: 529 fuse_change_attributes_i(inode, attr, NULL, attr_valid, attr_version, 530 evict_ctr); 531 return inode; 532 } 533 534 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid, 535 struct fuse_mount **fm) 536 { 537 struct fuse_mount *fm_iter; 538 struct inode *inode; 539 540 WARN_ON(!rwsem_is_locked(&fc->killsb)); 541 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) { 542 if (!fm_iter->sb) 543 continue; 544 545 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid); 546 if (inode) { 547 if (fm) 548 *fm = fm_iter; 549 return inode; 550 } 551 } 552 553 return NULL; 554 } 555 556 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid, 557 loff_t offset, loff_t len) 558 { 559 struct fuse_inode *fi; 560 struct inode *inode; 561 pgoff_t pg_start; 562 pgoff_t pg_end; 563 564 inode = fuse_ilookup(fc, nodeid, NULL); 565 if (!inode) 566 return -ENOENT; 567 568 fi = get_fuse_inode(inode); 569 spin_lock(&fi->lock); 570 fi->attr_version = atomic64_inc_return(&fc->attr_version); 571 spin_unlock(&fi->lock); 572 573 fuse_invalidate_attr(inode); 574 forget_all_cached_acls(inode); 575 if (offset >= 0) { 576 pg_start = offset >> PAGE_SHIFT; 577 if (len <= 0) 578 pg_end = -1; 579 else 580 pg_end = (offset + len - 1) >> PAGE_SHIFT; 581 invalidate_inode_pages2_range(inode->i_mapping, 582 pg_start, pg_end); 583 } 584 iput(inode); 585 return 0; 586 } 587 588 void fuse_try_prune_one_inode(struct fuse_conn *fc, u64 nodeid) 589 { 590 struct inode *inode; 591 592 inode = fuse_ilookup(fc, nodeid, NULL); 593 if (!inode) 594 return; 595 d_prune_aliases(inode); 596 iput(inode); 597 } 598 599 bool fuse_lock_inode(struct inode *inode) 600 { 601 bool locked = false; 602 603 if (!get_fuse_conn(inode)->parallel_dirops) { 604 mutex_lock(&get_fuse_inode(inode)->mutex); 605 locked = true; 606 } 607 608 return locked; 609 } 610 611 void fuse_unlock_inode(struct inode *inode, bool locked) 612 { 613 if (locked) 614 mutex_unlock(&get_fuse_inode(inode)->mutex); 615 } 616 617 static void fuse_umount_begin(struct super_block *sb) 618 { 619 struct fuse_conn *fc = get_fuse_conn_super(sb); 620 621 if (fc->no_force_umount) 622 return; 623 624 fuse_abort_conn(fc); 625 626 // Only retire block-device-based superblocks. 627 if (sb->s_bdev != NULL) 628 retire_super(sb); 629 } 630 631 static void fuse_send_destroy(struct fuse_mount *fm) 632 { 633 if (fm->fc->conn_init) { 634 FUSE_ARGS(args); 635 636 args.opcode = FUSE_DESTROY; 637 args.force = true; 638 args.nocreds = true; 639 fuse_simple_request(fm, &args); 640 } 641 } 642 643 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 644 { 645 stbuf->f_type = FUSE_SUPER_MAGIC; 646 stbuf->f_bsize = attr->bsize; 647 stbuf->f_frsize = attr->frsize; 648 stbuf->f_blocks = attr->blocks; 649 stbuf->f_bfree = attr->bfree; 650 stbuf->f_bavail = attr->bavail; 651 stbuf->f_files = attr->files; 652 stbuf->f_ffree = attr->ffree; 653 stbuf->f_namelen = attr->namelen; 654 /* fsid is left zero */ 655 } 656 657 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 658 { 659 struct super_block *sb = dentry->d_sb; 660 struct fuse_mount *fm = get_fuse_mount_super(sb); 661 FUSE_ARGS(args); 662 struct fuse_statfs_out outarg; 663 int err; 664 665 if (!fuse_allow_current_process(fm->fc)) { 666 buf->f_type = FUSE_SUPER_MAGIC; 667 return 0; 668 } 669 670 memset(&outarg, 0, sizeof(outarg)); 671 args.in_numargs = 0; 672 args.opcode = FUSE_STATFS; 673 args.nodeid = get_node_id(d_inode(dentry)); 674 args.out_numargs = 1; 675 args.out_args[0].size = sizeof(outarg); 676 args.out_args[0].value = &outarg; 677 err = fuse_simple_request(fm, &args); 678 if (!err) 679 convert_fuse_statfs(buf, &outarg.st); 680 return err; 681 } 682 683 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void) 684 { 685 struct fuse_sync_bucket *bucket; 686 687 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL); 688 if (bucket) { 689 init_waitqueue_head(&bucket->waitq); 690 /* Initial active count */ 691 atomic_set(&bucket->count, 1); 692 } 693 return bucket; 694 } 695 696 static void fuse_sync_fs_writes(struct fuse_conn *fc) 697 { 698 struct fuse_sync_bucket *bucket, *new_bucket; 699 int count; 700 701 new_bucket = fuse_sync_bucket_alloc(); 702 spin_lock(&fc->lock); 703 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 704 count = atomic_read(&bucket->count); 705 WARN_ON(count < 1); 706 /* No outstanding writes? */ 707 if (count == 1) { 708 spin_unlock(&fc->lock); 709 kfree(new_bucket); 710 return; 711 } 712 713 /* 714 * Completion of new bucket depends on completion of this bucket, so add 715 * one more count. 716 */ 717 atomic_inc(&new_bucket->count); 718 rcu_assign_pointer(fc->curr_bucket, new_bucket); 719 spin_unlock(&fc->lock); 720 /* 721 * Drop initial active count. At this point if all writes in this and 722 * ancestor buckets complete, the count will go to zero and this task 723 * will be woken up. 724 */ 725 atomic_dec(&bucket->count); 726 727 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0); 728 729 /* Drop temp count on descendant bucket */ 730 fuse_sync_bucket_dec(new_bucket); 731 kfree_rcu(bucket, rcu); 732 } 733 734 static int fuse_sync_fs(struct super_block *sb, int wait) 735 { 736 struct fuse_mount *fm = get_fuse_mount_super(sb); 737 struct fuse_conn *fc = fm->fc; 738 struct fuse_syncfs_in inarg; 739 FUSE_ARGS(args); 740 int err; 741 742 /* 743 * Userspace cannot handle the wait == 0 case. Avoid a 744 * gratuitous roundtrip. 745 */ 746 if (!wait) 747 return 0; 748 749 /* The filesystem is being unmounted. Nothing to do. */ 750 if (!sb->s_root) 751 return 0; 752 753 if (!fc->sync_fs) 754 return 0; 755 756 fuse_sync_fs_writes(fc); 757 758 memset(&inarg, 0, sizeof(inarg)); 759 args.in_numargs = 1; 760 args.in_args[0].size = sizeof(inarg); 761 args.in_args[0].value = &inarg; 762 args.opcode = FUSE_SYNCFS; 763 args.nodeid = get_node_id(sb->s_root->d_inode); 764 args.out_numargs = 0; 765 766 err = fuse_simple_request(fm, &args); 767 if (err == -ENOSYS) { 768 fc->sync_fs = 0; 769 err = 0; 770 } 771 772 return err; 773 } 774 775 enum { 776 OPT_SOURCE, 777 OPT_SUBTYPE, 778 OPT_FD, 779 OPT_ROOTMODE, 780 OPT_USER_ID, 781 OPT_GROUP_ID, 782 OPT_DEFAULT_PERMISSIONS, 783 OPT_ALLOW_OTHER, 784 OPT_MAX_READ, 785 OPT_BLKSIZE, 786 OPT_ERR 787 }; 788 789 static const struct fs_parameter_spec fuse_fs_parameters[] = { 790 fsparam_string ("source", OPT_SOURCE), 791 fsparam_u32 ("fd", OPT_FD), 792 fsparam_u32oct ("rootmode", OPT_ROOTMODE), 793 fsparam_uid ("user_id", OPT_USER_ID), 794 fsparam_gid ("group_id", OPT_GROUP_ID), 795 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS), 796 fsparam_flag ("allow_other", OPT_ALLOW_OTHER), 797 fsparam_u32 ("max_read", OPT_MAX_READ), 798 fsparam_u32 ("blksize", OPT_BLKSIZE), 799 fsparam_string ("subtype", OPT_SUBTYPE), 800 {} 801 }; 802 803 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param) 804 { 805 struct fs_parse_result result; 806 struct fuse_fs_context *ctx = fsc->fs_private; 807 int opt; 808 kuid_t kuid; 809 kgid_t kgid; 810 811 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { 812 /* 813 * Ignore options coming from mount(MS_REMOUNT) for backward 814 * compatibility. 815 */ 816 if (fsc->oldapi) 817 return 0; 818 819 return invalfc(fsc, "No changes allowed in reconfigure"); 820 } 821 822 opt = fs_parse(fsc, fuse_fs_parameters, param, &result); 823 if (opt < 0) 824 return opt; 825 826 switch (opt) { 827 case OPT_SOURCE: 828 if (fsc->source) 829 return invalfc(fsc, "Multiple sources specified"); 830 fsc->source = param->string; 831 param->string = NULL; 832 break; 833 834 case OPT_SUBTYPE: 835 if (ctx->subtype) 836 return invalfc(fsc, "Multiple subtypes specified"); 837 ctx->subtype = param->string; 838 param->string = NULL; 839 return 0; 840 841 case OPT_FD: 842 ctx->fd = result.uint_32; 843 ctx->fd_present = true; 844 break; 845 846 case OPT_ROOTMODE: 847 if (!fuse_valid_type(result.uint_32)) 848 return invalfc(fsc, "Invalid rootmode"); 849 ctx->rootmode = result.uint_32; 850 ctx->rootmode_present = true; 851 break; 852 853 case OPT_USER_ID: 854 kuid = result.uid; 855 /* 856 * The requested uid must be representable in the 857 * filesystem's idmapping. 858 */ 859 if (!kuid_has_mapping(fsc->user_ns, kuid)) 860 return invalfc(fsc, "Invalid user_id"); 861 ctx->user_id = kuid; 862 ctx->user_id_present = true; 863 break; 864 865 case OPT_GROUP_ID: 866 kgid = result.gid; 867 /* 868 * The requested gid must be representable in the 869 * filesystem's idmapping. 870 */ 871 if (!kgid_has_mapping(fsc->user_ns, kgid)) 872 return invalfc(fsc, "Invalid group_id"); 873 ctx->group_id = kgid; 874 ctx->group_id_present = true; 875 break; 876 877 case OPT_DEFAULT_PERMISSIONS: 878 ctx->default_permissions = true; 879 break; 880 881 case OPT_ALLOW_OTHER: 882 ctx->allow_other = true; 883 break; 884 885 case OPT_MAX_READ: 886 ctx->max_read = result.uint_32; 887 break; 888 889 case OPT_BLKSIZE: 890 if (!ctx->is_bdev) 891 return invalfc(fsc, "blksize only supported for fuseblk"); 892 ctx->blksize = result.uint_32; 893 break; 894 895 default: 896 return -EINVAL; 897 } 898 899 return 0; 900 } 901 902 static void fuse_free_fsc(struct fs_context *fsc) 903 { 904 struct fuse_fs_context *ctx = fsc->fs_private; 905 906 if (ctx) { 907 kfree(ctx->subtype); 908 kfree(ctx); 909 } 910 } 911 912 static int fuse_show_options(struct seq_file *m, struct dentry *root) 913 { 914 struct super_block *sb = root->d_sb; 915 struct fuse_conn *fc = get_fuse_conn_super(sb); 916 917 if (fc->legacy_opts_show) { 918 seq_printf(m, ",user_id=%u", 919 from_kuid_munged(fc->user_ns, fc->user_id)); 920 seq_printf(m, ",group_id=%u", 921 from_kgid_munged(fc->user_ns, fc->group_id)); 922 if (fc->default_permissions) 923 seq_puts(m, ",default_permissions"); 924 if (fc->allow_other) 925 seq_puts(m, ",allow_other"); 926 if (fc->max_read != ~0) 927 seq_printf(m, ",max_read=%u", fc->max_read); 928 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 929 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 930 } 931 #ifdef CONFIG_FUSE_DAX 932 if (fc->dax_mode == FUSE_DAX_ALWAYS) 933 seq_puts(m, ",dax=always"); 934 else if (fc->dax_mode == FUSE_DAX_NEVER) 935 seq_puts(m, ",dax=never"); 936 else if (fc->dax_mode == FUSE_DAX_INODE_USER) 937 seq_puts(m, ",dax=inode"); 938 #endif 939 940 return 0; 941 } 942 943 static void fuse_iqueue_init(struct fuse_iqueue *fiq, 944 const struct fuse_iqueue_ops *ops, 945 void *priv) 946 { 947 memset(fiq, 0, sizeof(struct fuse_iqueue)); 948 spin_lock_init(&fiq->lock); 949 init_waitqueue_head(&fiq->waitq); 950 INIT_LIST_HEAD(&fiq->pending); 951 INIT_LIST_HEAD(&fiq->interrupts); 952 fiq->forget_list_tail = &fiq->forget_list_head; 953 fiq->connected = 1; 954 fiq->ops = ops; 955 fiq->priv = priv; 956 } 957 958 void fuse_pqueue_init(struct fuse_pqueue *fpq) 959 { 960 unsigned int i; 961 962 spin_lock_init(&fpq->lock); 963 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 964 INIT_LIST_HEAD(&fpq->processing[i]); 965 INIT_LIST_HEAD(&fpq->io); 966 fpq->connected = 1; 967 } 968 969 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, 970 struct user_namespace *user_ns, 971 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv) 972 { 973 memset(fc, 0, sizeof(*fc)); 974 spin_lock_init(&fc->lock); 975 spin_lock_init(&fc->bg_lock); 976 init_rwsem(&fc->killsb); 977 refcount_set(&fc->count, 1); 978 atomic_set(&fc->dev_count, 1); 979 atomic_set(&fc->epoch, 1); 980 INIT_WORK(&fc->epoch_work, fuse_epoch_work); 981 init_waitqueue_head(&fc->blocked_waitq); 982 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv); 983 INIT_LIST_HEAD(&fc->bg_queue); 984 INIT_LIST_HEAD(&fc->entry); 985 INIT_LIST_HEAD(&fc->devices); 986 atomic_set(&fc->num_waiting, 0); 987 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 988 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 989 atomic64_set(&fc->khctr, 0); 990 fc->polled_files = RB_ROOT; 991 fc->blocked = 0; 992 fc->initialized = 0; 993 fc->connected = 1; 994 atomic64_set(&fc->attr_version, 1); 995 atomic64_set(&fc->evict_ctr, 1); 996 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 997 fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); 998 fc->user_ns = get_user_ns(user_ns); 999 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; 1000 fc->max_pages_limit = fuse_max_pages_limit; 1001 fc->name_max = FUSE_NAME_LOW_MAX; 1002 fc->timeout.req_timeout = 0; 1003 1004 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 1005 fuse_backing_files_init(fc); 1006 1007 INIT_LIST_HEAD(&fc->mounts); 1008 list_add(&fm->fc_entry, &fc->mounts); 1009 fm->fc = fc; 1010 } 1011 EXPORT_SYMBOL_GPL(fuse_conn_init); 1012 1013 static void delayed_release(struct rcu_head *p) 1014 { 1015 struct fuse_conn *fc = container_of(p, struct fuse_conn, rcu); 1016 1017 fuse_uring_destruct(fc); 1018 1019 put_user_ns(fc->user_ns); 1020 fc->release(fc); 1021 } 1022 1023 void fuse_conn_put(struct fuse_conn *fc) 1024 { 1025 struct fuse_iqueue *fiq = &fc->iq; 1026 struct fuse_sync_bucket *bucket; 1027 1028 if (!refcount_dec_and_test(&fc->count)) 1029 return; 1030 1031 if (IS_ENABLED(CONFIG_FUSE_DAX)) 1032 fuse_dax_conn_free(fc); 1033 if (fc->timeout.req_timeout) 1034 cancel_delayed_work_sync(&fc->timeout.work); 1035 cancel_work_sync(&fc->epoch_work); 1036 if (fiq->ops->release) 1037 fiq->ops->release(fiq); 1038 put_pid_ns(fc->pid_ns); 1039 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 1040 if (bucket) { 1041 WARN_ON(atomic_read(&bucket->count) != 1); 1042 kfree(bucket); 1043 } 1044 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 1045 fuse_backing_files_free(fc); 1046 call_rcu(&fc->rcu, delayed_release); 1047 } 1048 EXPORT_SYMBOL_GPL(fuse_conn_put); 1049 1050 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 1051 { 1052 refcount_inc(&fc->count); 1053 return fc; 1054 } 1055 EXPORT_SYMBOL_GPL(fuse_conn_get); 1056 1057 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned int mode) 1058 { 1059 struct fuse_attr attr; 1060 memset(&attr, 0, sizeof(attr)); 1061 1062 attr.mode = mode; 1063 attr.ino = FUSE_ROOT_ID; 1064 attr.nlink = 1; 1065 return fuse_iget(sb, FUSE_ROOT_ID, 0, &attr, 0, 0, 0); 1066 } 1067 1068 struct fuse_inode_handle { 1069 u64 nodeid; 1070 u32 generation; 1071 }; 1072 1073 static struct dentry *fuse_get_dentry(struct super_block *sb, 1074 struct fuse_inode_handle *handle) 1075 { 1076 struct fuse_conn *fc = get_fuse_conn_super(sb); 1077 struct inode *inode; 1078 struct dentry *entry; 1079 int err = -ESTALE; 1080 1081 if (handle->nodeid == 0) 1082 goto out_err; 1083 1084 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 1085 if (!inode) { 1086 struct fuse_entry_out outarg; 1087 const struct qstr name = QSTR_INIT(".", 1); 1088 1089 if (!fc->export_support) 1090 goto out_err; 1091 1092 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 1093 &inode); 1094 if (err && err != -ENOENT) 1095 goto out_err; 1096 if (err || !inode) { 1097 err = -ESTALE; 1098 goto out_err; 1099 } 1100 err = -EIO; 1101 if (get_node_id(inode) != handle->nodeid) 1102 goto out_iput; 1103 } 1104 err = -ESTALE; 1105 if (inode->i_generation != handle->generation) 1106 goto out_iput; 1107 1108 entry = d_obtain_alias(inode); 1109 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 1110 fuse_invalidate_entry_cache(entry); 1111 1112 return entry; 1113 1114 out_iput: 1115 iput(inode); 1116 out_err: 1117 return ERR_PTR(err); 1118 } 1119 1120 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 1121 struct inode *parent) 1122 { 1123 int len = parent ? 6 : 3; 1124 u64 nodeid; 1125 u32 generation; 1126 1127 if (*max_len < len) { 1128 *max_len = len; 1129 return FILEID_INVALID; 1130 } 1131 1132 nodeid = get_fuse_inode(inode)->nodeid; 1133 generation = inode->i_generation; 1134 1135 fh[0] = (u32)(nodeid >> 32); 1136 fh[1] = (u32)(nodeid & 0xffffffff); 1137 fh[2] = generation; 1138 1139 if (parent) { 1140 nodeid = get_fuse_inode(parent)->nodeid; 1141 generation = parent->i_generation; 1142 1143 fh[3] = (u32)(nodeid >> 32); 1144 fh[4] = (u32)(nodeid & 0xffffffff); 1145 fh[5] = generation; 1146 } 1147 1148 *max_len = len; 1149 return parent ? FILEID_INO64_GEN_PARENT : FILEID_INO64_GEN; 1150 } 1151 1152 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 1153 struct fid *fid, int fh_len, int fh_type) 1154 { 1155 struct fuse_inode_handle handle; 1156 1157 if ((fh_type != FILEID_INO64_GEN && 1158 fh_type != FILEID_INO64_GEN_PARENT) || fh_len < 3) 1159 return NULL; 1160 1161 handle.nodeid = (u64) fid->raw[0] << 32; 1162 handle.nodeid |= (u64) fid->raw[1]; 1163 handle.generation = fid->raw[2]; 1164 return fuse_get_dentry(sb, &handle); 1165 } 1166 1167 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 1168 struct fid *fid, int fh_len, int fh_type) 1169 { 1170 struct fuse_inode_handle parent; 1171 1172 if (fh_type != FILEID_INO64_GEN_PARENT || fh_len < 6) 1173 return NULL; 1174 1175 parent.nodeid = (u64) fid->raw[3] << 32; 1176 parent.nodeid |= (u64) fid->raw[4]; 1177 parent.generation = fid->raw[5]; 1178 return fuse_get_dentry(sb, &parent); 1179 } 1180 1181 static struct dentry *fuse_get_parent(struct dentry *child) 1182 { 1183 struct inode *child_inode = d_inode(child); 1184 struct fuse_conn *fc = get_fuse_conn(child_inode); 1185 struct inode *inode; 1186 struct dentry *parent; 1187 struct fuse_entry_out outarg; 1188 int err; 1189 1190 if (!fc->export_support) 1191 return ERR_PTR(-ESTALE); 1192 1193 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 1194 &dotdot_name, &outarg, &inode); 1195 if (err) { 1196 if (err == -ENOENT) 1197 return ERR_PTR(-ESTALE); 1198 return ERR_PTR(err); 1199 } 1200 1201 parent = d_obtain_alias(inode); 1202 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 1203 fuse_invalidate_entry_cache(parent); 1204 1205 return parent; 1206 } 1207 1208 /* only for fid encoding; no support for file handle */ 1209 static const struct export_operations fuse_export_fid_operations = { 1210 .encode_fh = fuse_encode_fh, 1211 }; 1212 1213 static const struct export_operations fuse_export_operations = { 1214 .fh_to_dentry = fuse_fh_to_dentry, 1215 .fh_to_parent = fuse_fh_to_parent, 1216 .encode_fh = fuse_encode_fh, 1217 .get_parent = fuse_get_parent, 1218 }; 1219 1220 static const struct super_operations fuse_super_operations = { 1221 .alloc_inode = fuse_alloc_inode, 1222 .free_inode = fuse_free_inode, 1223 .evict_inode = fuse_evict_inode, 1224 .write_inode = fuse_write_inode, 1225 .drop_inode = inode_just_drop, 1226 .umount_begin = fuse_umount_begin, 1227 .statfs = fuse_statfs, 1228 .sync_fs = fuse_sync_fs, 1229 .show_options = fuse_show_options, 1230 }; 1231 1232 static void sanitize_global_limit(unsigned int *limit) 1233 { 1234 /* 1235 * The default maximum number of async requests is calculated to consume 1236 * 1/2^13 of the total memory, assuming 392 bytes per request. 1237 */ 1238 if (*limit == 0) 1239 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392; 1240 1241 if (*limit >= 1 << 16) 1242 *limit = (1 << 16) - 1; 1243 } 1244 1245 static int set_global_limit(const char *val, const struct kernel_param *kp) 1246 { 1247 int rv; 1248 1249 rv = param_set_uint(val, kp); 1250 if (rv) 1251 return rv; 1252 1253 sanitize_global_limit((unsigned int *)kp->arg); 1254 1255 return 0; 1256 } 1257 1258 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 1259 { 1260 int cap_sys_admin = capable(CAP_SYS_ADMIN); 1261 1262 if (arg->minor < 13) 1263 return; 1264 1265 sanitize_global_limit(&max_user_bgreq); 1266 sanitize_global_limit(&max_user_congthresh); 1267 1268 spin_lock(&fc->bg_lock); 1269 if (arg->max_background) { 1270 fc->max_background = arg->max_background; 1271 1272 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 1273 fc->max_background = max_user_bgreq; 1274 } 1275 if (arg->congestion_threshold) { 1276 fc->congestion_threshold = arg->congestion_threshold; 1277 1278 if (!cap_sys_admin && 1279 fc->congestion_threshold > max_user_congthresh) 1280 fc->congestion_threshold = max_user_congthresh; 1281 } 1282 spin_unlock(&fc->bg_lock); 1283 } 1284 1285 static void set_request_timeout(struct fuse_conn *fc, unsigned int timeout) 1286 { 1287 fc->timeout.req_timeout = secs_to_jiffies(timeout); 1288 INIT_DELAYED_WORK(&fc->timeout.work, fuse_check_timeout); 1289 queue_delayed_work(system_percpu_wq, &fc->timeout.work, 1290 fuse_timeout_timer_freq); 1291 } 1292 1293 static void init_server_timeout(struct fuse_conn *fc, unsigned int timeout) 1294 { 1295 if (!timeout && !fuse_max_req_timeout && !fuse_default_req_timeout) 1296 return; 1297 1298 if (!timeout) 1299 timeout = fuse_default_req_timeout; 1300 1301 if (fuse_max_req_timeout) { 1302 if (timeout) 1303 timeout = min(fuse_max_req_timeout, timeout); 1304 else 1305 timeout = fuse_max_req_timeout; 1306 } 1307 1308 timeout = max(FUSE_TIMEOUT_TIMER_FREQ, timeout); 1309 1310 set_request_timeout(fc, timeout); 1311 } 1312 1313 struct fuse_init_args { 1314 struct fuse_args args; 1315 struct fuse_init_in in; 1316 struct fuse_init_out out; 1317 }; 1318 1319 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, 1320 int error) 1321 { 1322 struct fuse_conn *fc = fm->fc; 1323 struct fuse_init_args *ia = container_of(args, typeof(*ia), args); 1324 struct fuse_init_out *arg = &ia->out; 1325 bool ok = true; 1326 1327 if (error || arg->major != FUSE_KERNEL_VERSION) 1328 ok = false; 1329 else { 1330 unsigned long ra_pages; 1331 unsigned int timeout = 0; 1332 1333 process_init_limits(fc, arg); 1334 1335 if (arg->minor >= 6) { 1336 u64 flags = arg->flags; 1337 1338 if (flags & FUSE_INIT_EXT) 1339 flags |= (u64) arg->flags2 << 32; 1340 1341 ra_pages = arg->max_readahead / PAGE_SIZE; 1342 if (flags & FUSE_ASYNC_READ) 1343 fc->async_read = 1; 1344 if (!(flags & FUSE_POSIX_LOCKS)) 1345 fc->no_lock = 1; 1346 if (arg->minor >= 17) { 1347 if (!(flags & FUSE_FLOCK_LOCKS)) 1348 fc->no_flock = 1; 1349 } else { 1350 if (!(flags & FUSE_POSIX_LOCKS)) 1351 fc->no_flock = 1; 1352 } 1353 if (flags & FUSE_ATOMIC_O_TRUNC) 1354 fc->atomic_o_trunc = 1; 1355 if (arg->minor >= 9) { 1356 /* LOOKUP has dependency on proto version */ 1357 if (flags & FUSE_EXPORT_SUPPORT) 1358 fc->export_support = 1; 1359 } 1360 if (flags & FUSE_BIG_WRITES) 1361 fc->big_writes = 1; 1362 if (flags & FUSE_DONT_MASK) 1363 fc->dont_mask = 1; 1364 if (flags & FUSE_AUTO_INVAL_DATA) 1365 fc->auto_inval_data = 1; 1366 else if (flags & FUSE_EXPLICIT_INVAL_DATA) 1367 fc->explicit_inval_data = 1; 1368 if (flags & FUSE_DO_READDIRPLUS) { 1369 fc->do_readdirplus = 1; 1370 if (flags & FUSE_READDIRPLUS_AUTO) 1371 fc->readdirplus_auto = 1; 1372 } 1373 if (flags & FUSE_ASYNC_DIO) 1374 fc->async_dio = 1; 1375 if (flags & FUSE_WRITEBACK_CACHE) 1376 fc->writeback_cache = 1; 1377 if (flags & FUSE_PARALLEL_DIROPS) 1378 fc->parallel_dirops = 1; 1379 if (flags & FUSE_HANDLE_KILLPRIV) 1380 fc->handle_killpriv = 1; 1381 if (arg->time_gran && arg->time_gran <= 1000000000) 1382 fm->sb->s_time_gran = arg->time_gran; 1383 if ((flags & FUSE_POSIX_ACL)) { 1384 fc->default_permissions = 1; 1385 fc->posix_acl = 1; 1386 } 1387 if (flags & FUSE_CACHE_SYMLINKS) 1388 fc->cache_symlinks = 1; 1389 if (flags & FUSE_ABORT_ERROR) 1390 fc->abort_err = 1; 1391 if (flags & FUSE_MAX_PAGES) { 1392 fc->max_pages = 1393 min_t(unsigned int, fc->max_pages_limit, 1394 max_t(unsigned int, arg->max_pages, 1)); 1395 1396 /* 1397 * PATH_MAX file names might need two pages for 1398 * ops like rename 1399 */ 1400 if (fc->max_pages > 1) 1401 fc->name_max = FUSE_NAME_MAX; 1402 } 1403 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1404 if (flags & FUSE_MAP_ALIGNMENT && 1405 !fuse_dax_check_alignment(fc, arg->map_alignment)) { 1406 ok = false; 1407 } 1408 if (flags & FUSE_HAS_INODE_DAX) 1409 fc->inode_dax = 1; 1410 } 1411 if (flags & FUSE_HANDLE_KILLPRIV_V2) { 1412 fc->handle_killpriv_v2 = 1; 1413 fm->sb->s_flags |= SB_NOSEC; 1414 } 1415 if (flags & FUSE_SETXATTR_EXT) 1416 fc->setxattr_ext = 1; 1417 if (flags & FUSE_SECURITY_CTX) 1418 fc->init_security = 1; 1419 if (flags & FUSE_CREATE_SUPP_GROUP) 1420 fc->create_supp_group = 1; 1421 if (flags & FUSE_DIRECT_IO_ALLOW_MMAP) 1422 fc->direct_io_allow_mmap = 1; 1423 /* 1424 * max_stack_depth is the max stack depth of FUSE fs, 1425 * so it has to be at least 1 to support passthrough 1426 * to backing files. 1427 * 1428 * with max_stack_depth > 1, the backing files can be 1429 * on a stacked fs (e.g. overlayfs) themselves and with 1430 * max_stack_depth == 1, FUSE fs can be stacked as the 1431 * underlying fs of a stacked fs (e.g. overlayfs). 1432 * 1433 * Also don't allow the combination of FUSE_PASSTHROUGH 1434 * and FUSE_WRITEBACK_CACHE, current design doesn't handle 1435 * them together. 1436 */ 1437 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH) && 1438 (flags & FUSE_PASSTHROUGH) && 1439 arg->max_stack_depth > 0 && 1440 arg->max_stack_depth <= FILESYSTEM_MAX_STACK_DEPTH && 1441 !(flags & FUSE_WRITEBACK_CACHE)) { 1442 fc->passthrough = 1; 1443 fc->max_stack_depth = arg->max_stack_depth; 1444 fm->sb->s_stack_depth = arg->max_stack_depth; 1445 } 1446 if (flags & FUSE_NO_EXPORT_SUPPORT) 1447 fm->sb->s_export_op = &fuse_export_fid_operations; 1448 if (flags & FUSE_ALLOW_IDMAP) { 1449 if (fc->default_permissions) 1450 fm->sb->s_iflags &= ~SB_I_NOIDMAP; 1451 else 1452 ok = false; 1453 } 1454 if (flags & FUSE_OVER_IO_URING && fuse_uring_enabled()) 1455 fc->io_uring = 1; 1456 1457 if (flags & FUSE_REQUEST_TIMEOUT) 1458 timeout = arg->request_timeout; 1459 } else { 1460 ra_pages = fc->max_read / PAGE_SIZE; 1461 fc->no_lock = 1; 1462 fc->no_flock = 1; 1463 } 1464 1465 init_server_timeout(fc, timeout); 1466 1467 fm->sb->s_bdi->ra_pages = 1468 min(fm->sb->s_bdi->ra_pages, ra_pages); 1469 fc->minor = arg->minor; 1470 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 1471 fc->max_write = max_t(unsigned, 4096, fc->max_write); 1472 fc->conn_init = 1; 1473 } 1474 kfree(ia); 1475 1476 if (!ok) { 1477 fc->conn_init = 0; 1478 fc->conn_error = 1; 1479 } 1480 1481 fuse_set_initialized(fc); 1482 wake_up_all(&fc->blocked_waitq); 1483 } 1484 1485 static struct fuse_init_args *fuse_new_init(struct fuse_mount *fm) 1486 { 1487 struct fuse_init_args *ia; 1488 u64 flags; 1489 1490 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL); 1491 1492 ia->in.major = FUSE_KERNEL_VERSION; 1493 ia->in.minor = FUSE_KERNEL_MINOR_VERSION; 1494 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE; 1495 flags = 1496 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 1497 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 1498 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 1499 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 1500 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 1501 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | 1502 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL | 1503 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS | 1504 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | 1505 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT | 1506 FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP | 1507 FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_ALLOW_MMAP | 1508 FUSE_NO_EXPORT_SUPPORT | FUSE_HAS_RESEND | FUSE_ALLOW_IDMAP | 1509 FUSE_REQUEST_TIMEOUT; 1510 #ifdef CONFIG_FUSE_DAX 1511 if (fm->fc->dax) 1512 flags |= FUSE_MAP_ALIGNMENT; 1513 if (fuse_is_inode_dax_mode(fm->fc->dax_mode)) 1514 flags |= FUSE_HAS_INODE_DAX; 1515 #endif 1516 if (fm->fc->auto_submounts) 1517 flags |= FUSE_SUBMOUNTS; 1518 if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 1519 flags |= FUSE_PASSTHROUGH; 1520 1521 /* 1522 * This is just an information flag for fuse server. No need to check 1523 * the reply - server is either sending IORING_OP_URING_CMD or not. 1524 */ 1525 if (fuse_uring_enabled()) 1526 flags |= FUSE_OVER_IO_URING; 1527 1528 ia->in.flags = flags; 1529 ia->in.flags2 = flags >> 32; 1530 1531 ia->args.opcode = FUSE_INIT; 1532 ia->args.in_numargs = 1; 1533 ia->args.in_args[0].size = sizeof(ia->in); 1534 ia->args.in_args[0].value = &ia->in; 1535 ia->args.out_numargs = 1; 1536 /* Variable length argument used for backward compatibility 1537 with interface version < 7.5. Rest of init_out is zeroed 1538 by do_get_request(), so a short reply is not a problem */ 1539 ia->args.out_argvar = true; 1540 ia->args.out_args[0].size = sizeof(ia->out); 1541 ia->args.out_args[0].value = &ia->out; 1542 ia->args.force = true; 1543 ia->args.nocreds = true; 1544 1545 return ia; 1546 } 1547 1548 int fuse_send_init(struct fuse_mount *fm) 1549 { 1550 struct fuse_init_args *ia = fuse_new_init(fm); 1551 int err; 1552 1553 if (fm->fc->sync_init) { 1554 err = fuse_simple_request(fm, &ia->args); 1555 /* Ignore size of init reply */ 1556 if (err > 0) 1557 err = 0; 1558 } else { 1559 ia->args.end = process_init_reply; 1560 err = fuse_simple_background(fm, &ia->args, GFP_KERNEL); 1561 if (!err) 1562 return 0; 1563 } 1564 process_init_reply(fm, &ia->args, err); 1565 if (fm->fc->conn_error) 1566 return -ENOTCONN; 1567 return 0; 1568 } 1569 EXPORT_SYMBOL_GPL(fuse_send_init); 1570 1571 void fuse_free_conn(struct fuse_conn *fc) 1572 { 1573 WARN_ON(!list_empty(&fc->devices)); 1574 kfree(fc); 1575 } 1576 EXPORT_SYMBOL_GPL(fuse_free_conn); 1577 1578 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 1579 { 1580 int err; 1581 char *suffix = ""; 1582 1583 if (sb->s_bdev) { 1584 suffix = "-fuseblk"; 1585 /* 1586 * sb->s_bdi points to blkdev's bdi however we want to redirect 1587 * it to our private bdi... 1588 */ 1589 bdi_put(sb->s_bdi); 1590 sb->s_bdi = &noop_backing_dev_info; 1591 } 1592 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev), 1593 MINOR(fc->dev), suffix); 1594 if (err) 1595 return err; 1596 1597 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT; 1598 1599 /* 1600 * For a single fuse filesystem use max 1% of dirty + 1601 * writeback threshold. 1602 * 1603 * This gives about 1M of write buffer for memory maps on a 1604 * machine with 1G and 10% dirty_ratio, which should be more 1605 * than enough. 1606 * 1607 * Privileged users can raise it by writing to 1608 * 1609 * /sys/class/bdi/<bdi>/max_ratio 1610 */ 1611 bdi_set_max_ratio(sb->s_bdi, 1); 1612 1613 return 0; 1614 } 1615 1616 struct fuse_dev *fuse_dev_alloc(void) 1617 { 1618 struct fuse_dev *fud; 1619 struct list_head *pq; 1620 1621 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); 1622 if (!fud) 1623 return NULL; 1624 1625 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL); 1626 if (!pq) { 1627 kfree(fud); 1628 return NULL; 1629 } 1630 1631 fud->pq.processing = pq; 1632 fuse_pqueue_init(&fud->pq); 1633 1634 return fud; 1635 } 1636 EXPORT_SYMBOL_GPL(fuse_dev_alloc); 1637 1638 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) 1639 { 1640 fud->fc = fuse_conn_get(fc); 1641 spin_lock(&fc->lock); 1642 list_add_tail(&fud->entry, &fc->devices); 1643 spin_unlock(&fc->lock); 1644 } 1645 EXPORT_SYMBOL_GPL(fuse_dev_install); 1646 1647 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) 1648 { 1649 struct fuse_dev *fud; 1650 1651 fud = fuse_dev_alloc(); 1652 if (!fud) 1653 return NULL; 1654 1655 fuse_dev_install(fud, fc); 1656 return fud; 1657 } 1658 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); 1659 1660 void fuse_dev_free(struct fuse_dev *fud) 1661 { 1662 struct fuse_conn *fc = fud->fc; 1663 1664 if (fc) { 1665 spin_lock(&fc->lock); 1666 list_del(&fud->entry); 1667 spin_unlock(&fc->lock); 1668 1669 fuse_conn_put(fc); 1670 } 1671 kfree(fud->pq.processing); 1672 kfree(fud); 1673 } 1674 EXPORT_SYMBOL_GPL(fuse_dev_free); 1675 1676 static void fuse_fill_attr_from_inode(struct fuse_attr *attr, 1677 const struct fuse_inode *fi) 1678 { 1679 struct timespec64 atime = inode_get_atime(&fi->inode); 1680 struct timespec64 mtime = inode_get_mtime(&fi->inode); 1681 struct timespec64 ctime = inode_get_ctime(&fi->inode); 1682 1683 *attr = (struct fuse_attr){ 1684 .ino = fi->inode.i_ino, 1685 .size = fi->inode.i_size, 1686 .blocks = fi->inode.i_blocks, 1687 .atime = atime.tv_sec, 1688 .mtime = mtime.tv_sec, 1689 .ctime = ctime.tv_sec, 1690 .atimensec = atime.tv_nsec, 1691 .mtimensec = mtime.tv_nsec, 1692 .ctimensec = ctime.tv_nsec, 1693 .mode = fi->inode.i_mode, 1694 .nlink = fi->inode.i_nlink, 1695 .uid = __kuid_val(fi->inode.i_uid), 1696 .gid = __kgid_val(fi->inode.i_gid), 1697 .rdev = fi->inode.i_rdev, 1698 .blksize = 1u << fi->inode.i_blkbits, 1699 }; 1700 } 1701 1702 static void fuse_sb_defaults(struct super_block *sb) 1703 { 1704 sb->s_magic = FUSE_SUPER_MAGIC; 1705 sb->s_op = &fuse_super_operations; 1706 sb->s_xattr = fuse_xattr_handlers; 1707 sb->s_maxbytes = MAX_LFS_FILESIZE; 1708 sb->s_time_gran = 1; 1709 sb->s_export_op = &fuse_export_operations; 1710 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; 1711 sb->s_iflags |= SB_I_NOIDMAP; 1712 if (sb->s_user_ns != &init_user_ns) 1713 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; 1714 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); 1715 } 1716 1717 static int fuse_fill_super_submount(struct super_block *sb, 1718 struct fuse_inode *parent_fi) 1719 { 1720 struct fuse_mount *fm = get_fuse_mount_super(sb); 1721 struct super_block *parent_sb = parent_fi->inode.i_sb; 1722 struct fuse_attr root_attr; 1723 struct inode *root; 1724 struct fuse_submount_lookup *sl; 1725 struct fuse_inode *fi; 1726 1727 fuse_sb_defaults(sb); 1728 fm->sb = sb; 1729 1730 WARN_ON(sb->s_bdi != &noop_backing_dev_info); 1731 sb->s_bdi = bdi_get(parent_sb->s_bdi); 1732 1733 sb->s_xattr = parent_sb->s_xattr; 1734 sb->s_export_op = parent_sb->s_export_op; 1735 sb->s_time_gran = parent_sb->s_time_gran; 1736 sb->s_blocksize = parent_sb->s_blocksize; 1737 sb->s_blocksize_bits = parent_sb->s_blocksize_bits; 1738 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL); 1739 if (parent_sb->s_subtype && !sb->s_subtype) 1740 return -ENOMEM; 1741 1742 fuse_fill_attr_from_inode(&root_attr, parent_fi); 1743 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0, 1744 fuse_get_evict_ctr(fm->fc)); 1745 /* 1746 * This inode is just a duplicate, so it is not looked up and 1747 * its nlookup should not be incremented. fuse_iget() does 1748 * that, though, so undo it here. 1749 */ 1750 fi = get_fuse_inode(root); 1751 fi->nlookup--; 1752 1753 set_default_d_op(sb, &fuse_dentry_operations); 1754 sb->s_root = d_make_root(root); 1755 if (!sb->s_root) 1756 return -ENOMEM; 1757 1758 /* 1759 * Grab the parent's submount_lookup pointer and take a 1760 * reference on the shared nlookup from the parent. This is to 1761 * prevent the last forget for this nodeid from getting 1762 * triggered until all users have finished with it. 1763 */ 1764 sl = parent_fi->submount_lookup; 1765 WARN_ON(!sl); 1766 if (sl) { 1767 refcount_inc(&sl->count); 1768 fi->submount_lookup = sl; 1769 } 1770 1771 return 0; 1772 } 1773 1774 /* Filesystem context private data holds the FUSE inode of the mount point */ 1775 static int fuse_get_tree_submount(struct fs_context *fsc) 1776 { 1777 struct fuse_mount *fm; 1778 struct fuse_inode *mp_fi = fsc->fs_private; 1779 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); 1780 struct super_block *sb; 1781 int err; 1782 1783 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); 1784 if (!fm) 1785 return -ENOMEM; 1786 1787 fm->fc = fuse_conn_get(fc); 1788 fsc->s_fs_info = fm; 1789 sb = sget_fc(fsc, NULL, set_anon_super_fc); 1790 if (fsc->s_fs_info) 1791 fuse_mount_destroy(fm); 1792 if (IS_ERR(sb)) 1793 return PTR_ERR(sb); 1794 1795 /* Initialize superblock, making @mp_fi its root */ 1796 err = fuse_fill_super_submount(sb, mp_fi); 1797 if (err) { 1798 deactivate_locked_super(sb); 1799 return err; 1800 } 1801 1802 down_write(&fc->killsb); 1803 list_add_tail(&fm->fc_entry, &fc->mounts); 1804 up_write(&fc->killsb); 1805 1806 sb->s_flags |= SB_ACTIVE; 1807 fsc->root = dget(sb->s_root); 1808 1809 return 0; 1810 } 1811 1812 static const struct fs_context_operations fuse_context_submount_ops = { 1813 .get_tree = fuse_get_tree_submount, 1814 }; 1815 1816 int fuse_init_fs_context_submount(struct fs_context *fsc) 1817 { 1818 fsc->ops = &fuse_context_submount_ops; 1819 return 0; 1820 } 1821 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); 1822 1823 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 1824 { 1825 struct fuse_dev *fud = NULL; 1826 struct fuse_mount *fm = get_fuse_mount_super(sb); 1827 struct fuse_conn *fc = fm->fc; 1828 struct inode *root; 1829 struct dentry *root_dentry; 1830 int err; 1831 1832 err = -EINVAL; 1833 if (sb->s_flags & SB_MANDLOCK) 1834 goto err; 1835 1836 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc()); 1837 fuse_sb_defaults(sb); 1838 1839 if (ctx->is_bdev) { 1840 #ifdef CONFIG_BLOCK 1841 err = -EINVAL; 1842 if (!sb_set_blocksize(sb, ctx->blksize)) 1843 goto err; 1844 #endif 1845 fc->sync_fs = 1; 1846 } else { 1847 sb->s_blocksize = PAGE_SIZE; 1848 sb->s_blocksize_bits = PAGE_SHIFT; 1849 } 1850 1851 sb->s_subtype = ctx->subtype; 1852 ctx->subtype = NULL; 1853 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1854 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev); 1855 if (err) 1856 goto err; 1857 } 1858 1859 if (ctx->fudptr) { 1860 err = -ENOMEM; 1861 fud = fuse_dev_alloc_install(fc); 1862 if (!fud) 1863 goto err_free_dax; 1864 } 1865 1866 fc->dev = sb->s_dev; 1867 fm->sb = sb; 1868 err = fuse_bdi_init(fc, sb); 1869 if (err) 1870 goto err_dev_free; 1871 1872 /* Handle umasking inside the fuse code */ 1873 if (sb->s_flags & SB_POSIXACL) 1874 fc->dont_mask = 1; 1875 sb->s_flags |= SB_POSIXACL; 1876 1877 fc->default_permissions = ctx->default_permissions; 1878 fc->allow_other = ctx->allow_other; 1879 fc->user_id = ctx->user_id; 1880 fc->group_id = ctx->group_id; 1881 fc->legacy_opts_show = ctx->legacy_opts_show; 1882 fc->max_read = max_t(unsigned int, 4096, ctx->max_read); 1883 fc->destroy = ctx->destroy; 1884 fc->no_control = ctx->no_control; 1885 fc->no_force_umount = ctx->no_force_umount; 1886 1887 err = -ENOMEM; 1888 root = fuse_get_root_inode(sb, ctx->rootmode); 1889 set_default_d_op(sb, &fuse_dentry_operations); 1890 root_dentry = d_make_root(root); 1891 if (!root_dentry) 1892 goto err_dev_free; 1893 1894 mutex_lock(&fuse_mutex); 1895 err = -EINVAL; 1896 if (ctx->fudptr && *ctx->fudptr) { 1897 if (*ctx->fudptr == FUSE_DEV_SYNC_INIT) 1898 fc->sync_init = 1; 1899 else 1900 goto err_unlock; 1901 } 1902 1903 err = fuse_ctl_add_conn(fc); 1904 if (err) 1905 goto err_unlock; 1906 1907 list_add_tail(&fc->entry, &fuse_conn_list); 1908 sb->s_root = root_dentry; 1909 if (ctx->fudptr) { 1910 *ctx->fudptr = fud; 1911 wake_up_all(&fuse_dev_waitq); 1912 } 1913 mutex_unlock(&fuse_mutex); 1914 return 0; 1915 1916 err_unlock: 1917 mutex_unlock(&fuse_mutex); 1918 dput(root_dentry); 1919 err_dev_free: 1920 if (fud) 1921 fuse_dev_free(fud); 1922 err_free_dax: 1923 if (IS_ENABLED(CONFIG_FUSE_DAX)) 1924 fuse_dax_conn_free(fc); 1925 err: 1926 return err; 1927 } 1928 EXPORT_SYMBOL_GPL(fuse_fill_super_common); 1929 1930 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 1931 { 1932 struct fuse_fs_context *ctx = fsc->fs_private; 1933 struct fuse_mount *fm; 1934 int err; 1935 1936 if (!ctx->file || !ctx->rootmode_present || 1937 !ctx->user_id_present || !ctx->group_id_present) 1938 return -EINVAL; 1939 1940 /* 1941 * Require mount to happen from the same user namespace which 1942 * opened /dev/fuse to prevent potential attacks. 1943 */ 1944 if ((ctx->file->f_op != &fuse_dev_operations) || 1945 (ctx->file->f_cred->user_ns != sb->s_user_ns)) 1946 return -EINVAL; 1947 ctx->fudptr = &ctx->file->private_data; 1948 1949 err = fuse_fill_super_common(sb, ctx); 1950 if (err) 1951 return err; 1952 /* file->private_data shall be visible on all CPUs after this */ 1953 smp_mb(); 1954 1955 fm = get_fuse_mount_super(sb); 1956 1957 return fuse_send_init(fm); 1958 } 1959 1960 /* 1961 * This is the path where user supplied an already initialized fuse dev. In 1962 * this case never create a new super if the old one is gone. 1963 */ 1964 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc) 1965 { 1966 return -ENOTCONN; 1967 } 1968 1969 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc) 1970 { 1971 1972 return fsc->sget_key == get_fuse_conn_super(sb); 1973 } 1974 1975 static int fuse_get_tree(struct fs_context *fsc) 1976 { 1977 struct fuse_fs_context *ctx = fsc->fs_private; 1978 struct fuse_dev *fud; 1979 struct fuse_conn *fc; 1980 struct fuse_mount *fm; 1981 struct super_block *sb; 1982 int err; 1983 1984 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1985 if (!fc) 1986 return -ENOMEM; 1987 1988 fm = kzalloc(sizeof(*fm), GFP_KERNEL); 1989 if (!fm) { 1990 kfree(fc); 1991 return -ENOMEM; 1992 } 1993 1994 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL); 1995 fc->release = fuse_free_conn; 1996 1997 fsc->s_fs_info = fm; 1998 1999 if (ctx->fd_present) 2000 ctx->file = fget(ctx->fd); 2001 2002 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) { 2003 err = get_tree_bdev(fsc, fuse_fill_super); 2004 goto out; 2005 } 2006 /* 2007 * While block dev mount can be initialized with a dummy device fd 2008 * (found by device name), normal fuse mounts can't 2009 */ 2010 err = -EINVAL; 2011 if (!ctx->file) 2012 goto out; 2013 2014 /* 2015 * Allow creating a fuse mount with an already initialized fuse 2016 * connection 2017 */ 2018 fud = __fuse_get_dev(ctx->file); 2019 if (ctx->file->f_op == &fuse_dev_operations && fud) { 2020 fsc->sget_key = fud->fc; 2021 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super); 2022 err = PTR_ERR_OR_ZERO(sb); 2023 if (!IS_ERR(sb)) 2024 fsc->root = dget(sb->s_root); 2025 } else { 2026 err = get_tree_nodev(fsc, fuse_fill_super); 2027 } 2028 out: 2029 if (fsc->s_fs_info) 2030 fuse_mount_destroy(fm); 2031 if (ctx->file) 2032 fput(ctx->file); 2033 return err; 2034 } 2035 2036 static const struct fs_context_operations fuse_context_ops = { 2037 .free = fuse_free_fsc, 2038 .parse_param = fuse_parse_param, 2039 .reconfigure = fuse_reconfigure, 2040 .get_tree = fuse_get_tree, 2041 }; 2042 2043 /* 2044 * Set up the filesystem mount context. 2045 */ 2046 static int fuse_init_fs_context(struct fs_context *fsc) 2047 { 2048 struct fuse_fs_context *ctx; 2049 2050 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); 2051 if (!ctx) 2052 return -ENOMEM; 2053 2054 ctx->max_read = ~0; 2055 ctx->blksize = FUSE_DEFAULT_BLKSIZE; 2056 ctx->legacy_opts_show = true; 2057 2058 #ifdef CONFIG_BLOCK 2059 if (fsc->fs_type == &fuseblk_fs_type) { 2060 ctx->is_bdev = true; 2061 ctx->destroy = true; 2062 } 2063 #endif 2064 2065 fsc->fs_private = ctx; 2066 fsc->ops = &fuse_context_ops; 2067 return 0; 2068 } 2069 2070 bool fuse_mount_remove(struct fuse_mount *fm) 2071 { 2072 struct fuse_conn *fc = fm->fc; 2073 bool last = false; 2074 2075 down_write(&fc->killsb); 2076 list_del_init(&fm->fc_entry); 2077 if (list_empty(&fc->mounts)) 2078 last = true; 2079 up_write(&fc->killsb); 2080 2081 return last; 2082 } 2083 EXPORT_SYMBOL_GPL(fuse_mount_remove); 2084 2085 void fuse_conn_destroy(struct fuse_mount *fm) 2086 { 2087 struct fuse_conn *fc = fm->fc; 2088 2089 if (fc->destroy) 2090 fuse_send_destroy(fm); 2091 2092 fuse_abort_conn(fc); 2093 fuse_wait_aborted(fc); 2094 2095 if (!list_empty(&fc->entry)) { 2096 mutex_lock(&fuse_mutex); 2097 list_del(&fc->entry); 2098 fuse_ctl_remove_conn(fc); 2099 mutex_unlock(&fuse_mutex); 2100 } 2101 } 2102 EXPORT_SYMBOL_GPL(fuse_conn_destroy); 2103 2104 static void fuse_sb_destroy(struct super_block *sb) 2105 { 2106 struct fuse_mount *fm = get_fuse_mount_super(sb); 2107 bool last; 2108 2109 if (sb->s_root) { 2110 last = fuse_mount_remove(fm); 2111 if (last) 2112 fuse_conn_destroy(fm); 2113 } 2114 } 2115 2116 void fuse_mount_destroy(struct fuse_mount *fm) 2117 { 2118 fuse_conn_put(fm->fc); 2119 kfree_rcu(fm, rcu); 2120 } 2121 EXPORT_SYMBOL(fuse_mount_destroy); 2122 2123 static void fuse_kill_sb_anon(struct super_block *sb) 2124 { 2125 fuse_sb_destroy(sb); 2126 kill_anon_super(sb); 2127 fuse_mount_destroy(get_fuse_mount_super(sb)); 2128 } 2129 2130 static struct file_system_type fuse_fs_type = { 2131 .owner = THIS_MODULE, 2132 .name = "fuse", 2133 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT | FS_ALLOW_IDMAP, 2134 .init_fs_context = fuse_init_fs_context, 2135 .parameters = fuse_fs_parameters, 2136 .kill_sb = fuse_kill_sb_anon, 2137 }; 2138 MODULE_ALIAS_FS("fuse"); 2139 2140 #ifdef CONFIG_BLOCK 2141 static void fuse_kill_sb_blk(struct super_block *sb) 2142 { 2143 fuse_sb_destroy(sb); 2144 kill_block_super(sb); 2145 fuse_mount_destroy(get_fuse_mount_super(sb)); 2146 } 2147 2148 static struct file_system_type fuseblk_fs_type = { 2149 .owner = THIS_MODULE, 2150 .name = "fuseblk", 2151 .init_fs_context = fuse_init_fs_context, 2152 .parameters = fuse_fs_parameters, 2153 .kill_sb = fuse_kill_sb_blk, 2154 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE | FS_ALLOW_IDMAP, 2155 }; 2156 MODULE_ALIAS_FS("fuseblk"); 2157 2158 static inline int register_fuseblk(void) 2159 { 2160 return register_filesystem(&fuseblk_fs_type); 2161 } 2162 2163 static inline void unregister_fuseblk(void) 2164 { 2165 unregister_filesystem(&fuseblk_fs_type); 2166 } 2167 #else 2168 static inline int register_fuseblk(void) 2169 { 2170 return 0; 2171 } 2172 2173 static inline void unregister_fuseblk(void) 2174 { 2175 } 2176 #endif 2177 2178 static void fuse_inode_init_once(void *foo) 2179 { 2180 struct inode *inode = foo; 2181 2182 inode_init_once(inode); 2183 } 2184 2185 static int __init fuse_fs_init(void) 2186 { 2187 int err; 2188 2189 fuse_inode_cachep = kmem_cache_create("fuse_inode", 2190 sizeof(struct fuse_inode), 0, 2191 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT, 2192 fuse_inode_init_once); 2193 err = -ENOMEM; 2194 if (!fuse_inode_cachep) 2195 goto out; 2196 2197 err = register_fuseblk(); 2198 if (err) 2199 goto out2; 2200 2201 err = register_filesystem(&fuse_fs_type); 2202 if (err) 2203 goto out3; 2204 2205 err = fuse_sysctl_register(); 2206 if (err) 2207 goto out4; 2208 2209 return 0; 2210 2211 out4: 2212 unregister_filesystem(&fuse_fs_type); 2213 out3: 2214 unregister_fuseblk(); 2215 out2: 2216 kmem_cache_destroy(fuse_inode_cachep); 2217 out: 2218 return err; 2219 } 2220 2221 static void fuse_fs_cleanup(void) 2222 { 2223 fuse_sysctl_unregister(); 2224 unregister_filesystem(&fuse_fs_type); 2225 unregister_fuseblk(); 2226 2227 /* 2228 * Make sure all delayed rcu free inodes are flushed before we 2229 * destroy cache. 2230 */ 2231 rcu_barrier(); 2232 kmem_cache_destroy(fuse_inode_cachep); 2233 } 2234 2235 static struct kobject *fuse_kobj; 2236 2237 static int fuse_sysfs_init(void) 2238 { 2239 int err; 2240 2241 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 2242 if (!fuse_kobj) { 2243 err = -ENOMEM; 2244 goto out_err; 2245 } 2246 2247 err = sysfs_create_mount_point(fuse_kobj, "connections"); 2248 if (err) 2249 goto out_fuse_unregister; 2250 2251 return 0; 2252 2253 out_fuse_unregister: 2254 kobject_put(fuse_kobj); 2255 out_err: 2256 return err; 2257 } 2258 2259 static void fuse_sysfs_cleanup(void) 2260 { 2261 sysfs_remove_mount_point(fuse_kobj, "connections"); 2262 kobject_put(fuse_kobj); 2263 } 2264 2265 static int __init fuse_init(void) 2266 { 2267 int res; 2268 2269 pr_info("init (API version %i.%i)\n", 2270 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 2271 2272 INIT_LIST_HEAD(&fuse_conn_list); 2273 res = fuse_fs_init(); 2274 if (res) 2275 goto err; 2276 2277 res = fuse_dev_init(); 2278 if (res) 2279 goto err_fs_cleanup; 2280 2281 res = fuse_sysfs_init(); 2282 if (res) 2283 goto err_dev_cleanup; 2284 2285 res = fuse_ctl_init(); 2286 if (res) 2287 goto err_sysfs_cleanup; 2288 2289 fuse_dentry_tree_init(); 2290 2291 sanitize_global_limit(&max_user_bgreq); 2292 sanitize_global_limit(&max_user_congthresh); 2293 2294 return 0; 2295 2296 err_sysfs_cleanup: 2297 fuse_sysfs_cleanup(); 2298 err_dev_cleanup: 2299 fuse_dev_cleanup(); 2300 err_fs_cleanup: 2301 fuse_fs_cleanup(); 2302 err: 2303 return res; 2304 } 2305 2306 static void __exit fuse_exit(void) 2307 { 2308 pr_debug("exit\n"); 2309 2310 fuse_dentry_tree_cleanup(); 2311 fuse_ctl_cleanup(); 2312 fuse_sysfs_cleanup(); 2313 fuse_fs_cleanup(); 2314 fuse_dev_cleanup(); 2315 } 2316 2317 module_init(fuse_init); 2318 module_exit(fuse_exit); 2319