1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/slab.h> 13 #include <linux/file.h> 14 #include <linux/seq_file.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/fs_context.h> 19 #include <linux/fs_parser.h> 20 #include <linux/statfs.h> 21 #include <linux/random.h> 22 #include <linux/sched.h> 23 #include <linux/exportfs.h> 24 #include <linux/posix_acl.h> 25 #include <linux/pid_namespace.h> 26 27 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 28 MODULE_DESCRIPTION("Filesystem in Userspace"); 29 MODULE_LICENSE("GPL"); 30 31 static struct kmem_cache *fuse_inode_cachep; 32 struct list_head fuse_conn_list; 33 DEFINE_MUTEX(fuse_mutex); 34 35 static int set_global_limit(const char *val, const struct kernel_param *kp); 36 37 unsigned max_user_bgreq; 38 module_param_call(max_user_bgreq, set_global_limit, param_get_uint, 39 &max_user_bgreq, 0644); 40 __MODULE_PARM_TYPE(max_user_bgreq, "uint"); 41 MODULE_PARM_DESC(max_user_bgreq, 42 "Global limit for the maximum number of backgrounded requests an " 43 "unprivileged user can set"); 44 45 unsigned max_user_congthresh; 46 module_param_call(max_user_congthresh, set_global_limit, param_get_uint, 47 &max_user_congthresh, 0644); 48 __MODULE_PARM_TYPE(max_user_congthresh, "uint"); 49 MODULE_PARM_DESC(max_user_congthresh, 50 "Global limit for the maximum congestion threshold an " 51 "unprivileged user can set"); 52 53 #define FUSE_SUPER_MAGIC 0x65735546 54 55 #define FUSE_DEFAULT_BLKSIZE 512 56 57 /** Maximum number of outstanding background requests */ 58 #define FUSE_DEFAULT_MAX_BACKGROUND 12 59 60 /** Congestion starts at 75% of maximum */ 61 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) 62 63 #ifdef CONFIG_BLOCK 64 static struct file_system_type fuseblk_fs_type; 65 #endif 66 67 struct fuse_forget_link *fuse_alloc_forget(void) 68 { 69 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT); 70 } 71 72 static struct inode *fuse_alloc_inode(struct super_block *sb) 73 { 74 struct fuse_inode *fi; 75 76 fi = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL); 77 if (!fi) 78 return NULL; 79 80 fi->i_time = 0; 81 fi->inval_mask = 0; 82 fi->nodeid = 0; 83 fi->nlookup = 0; 84 fi->attr_version = 0; 85 fi->orig_ino = 0; 86 fi->state = 0; 87 mutex_init(&fi->mutex); 88 spin_lock_init(&fi->lock); 89 fi->forget = fuse_alloc_forget(); 90 if (!fi->forget) 91 goto out_free; 92 93 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi)) 94 goto out_free_forget; 95 96 return &fi->inode; 97 98 out_free_forget: 99 kfree(fi->forget); 100 out_free: 101 kmem_cache_free(fuse_inode_cachep, fi); 102 return NULL; 103 } 104 105 static void fuse_free_inode(struct inode *inode) 106 { 107 struct fuse_inode *fi = get_fuse_inode(inode); 108 109 mutex_destroy(&fi->mutex); 110 kfree(fi->forget); 111 #ifdef CONFIG_FUSE_DAX 112 kfree(fi->dax); 113 #endif 114 kmem_cache_free(fuse_inode_cachep, fi); 115 } 116 117 static void fuse_evict_inode(struct inode *inode) 118 { 119 struct fuse_inode *fi = get_fuse_inode(inode); 120 121 truncate_inode_pages_final(&inode->i_data); 122 clear_inode(inode); 123 if (inode->i_sb->s_flags & SB_ACTIVE) { 124 struct fuse_conn *fc = get_fuse_conn(inode); 125 126 if (FUSE_IS_DAX(inode)) 127 fuse_dax_inode_cleanup(inode); 128 if (fi->nlookup) { 129 fuse_queue_forget(fc, fi->forget, fi->nodeid, 130 fi->nlookup); 131 fi->forget = NULL; 132 } 133 } 134 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) { 135 WARN_ON(!list_empty(&fi->write_files)); 136 WARN_ON(!list_empty(&fi->queued_writes)); 137 } 138 } 139 140 static int fuse_reconfigure(struct fs_context *fsc) 141 { 142 struct super_block *sb = fsc->root->d_sb; 143 144 sync_filesystem(sb); 145 if (fsc->sb_flags & SB_MANDLOCK) 146 return -EINVAL; 147 148 return 0; 149 } 150 151 /* 152 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down 153 * so that it will fit. 154 */ 155 static ino_t fuse_squash_ino(u64 ino64) 156 { 157 ino_t ino = (ino_t) ino64; 158 if (sizeof(ino_t) < sizeof(u64)) 159 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; 160 return ino; 161 } 162 163 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 164 u64 attr_valid) 165 { 166 struct fuse_conn *fc = get_fuse_conn(inode); 167 struct fuse_inode *fi = get_fuse_inode(inode); 168 169 lockdep_assert_held(&fi->lock); 170 171 fi->attr_version = atomic64_inc_return(&fc->attr_version); 172 fi->i_time = attr_valid; 173 WRITE_ONCE(fi->inval_mask, 0); 174 175 inode->i_ino = fuse_squash_ino(attr->ino); 176 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 177 set_nlink(inode, attr->nlink); 178 inode->i_uid = make_kuid(fc->user_ns, attr->uid); 179 inode->i_gid = make_kgid(fc->user_ns, attr->gid); 180 inode->i_blocks = attr->blocks; 181 inode->i_atime.tv_sec = attr->atime; 182 inode->i_atime.tv_nsec = attr->atimensec; 183 /* mtime from server may be stale due to local buffered write */ 184 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) { 185 inode->i_mtime.tv_sec = attr->mtime; 186 inode->i_mtime.tv_nsec = attr->mtimensec; 187 inode->i_ctime.tv_sec = attr->ctime; 188 inode->i_ctime.tv_nsec = attr->ctimensec; 189 } 190 191 if (attr->blksize != 0) 192 inode->i_blkbits = ilog2(attr->blksize); 193 else 194 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 195 196 /* 197 * Don't set the sticky bit in i_mode, unless we want the VFS 198 * to check permissions. This prevents failures due to the 199 * check in may_delete(). 200 */ 201 fi->orig_i_mode = inode->i_mode; 202 if (!fc->default_permissions) 203 inode->i_mode &= ~S_ISVTX; 204 205 fi->orig_ino = attr->ino; 206 207 /* 208 * We are refreshing inode data and it is possible that another 209 * client set suid/sgid or security.capability xattr. So clear 210 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid 211 * was set or if security.capability xattr was set. But we don't 212 * know if security.capability has been set or not. So clear it 213 * anyway. Its less efficient but should be safe. 214 */ 215 inode->i_flags &= ~S_NOSEC; 216 } 217 218 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 219 u64 attr_valid, u64 attr_version) 220 { 221 struct fuse_conn *fc = get_fuse_conn(inode); 222 struct fuse_inode *fi = get_fuse_inode(inode); 223 bool is_wb = fc->writeback_cache; 224 loff_t oldsize; 225 struct timespec64 old_mtime; 226 227 spin_lock(&fi->lock); 228 if ((attr_version != 0 && fi->attr_version > attr_version) || 229 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { 230 spin_unlock(&fi->lock); 231 return; 232 } 233 234 old_mtime = inode->i_mtime; 235 fuse_change_attributes_common(inode, attr, attr_valid); 236 237 oldsize = inode->i_size; 238 /* 239 * In case of writeback_cache enabled, the cached writes beyond EOF 240 * extend local i_size without keeping userspace server in sync. So, 241 * attr->size coming from server can be stale. We cannot trust it. 242 */ 243 if (!is_wb || !S_ISREG(inode->i_mode)) 244 i_size_write(inode, attr->size); 245 spin_unlock(&fi->lock); 246 247 if (!is_wb && S_ISREG(inode->i_mode)) { 248 bool inval = false; 249 250 if (oldsize != attr->size) { 251 truncate_pagecache(inode, attr->size); 252 if (!fc->explicit_inval_data) 253 inval = true; 254 } else if (fc->auto_inval_data) { 255 struct timespec64 new_mtime = { 256 .tv_sec = attr->mtime, 257 .tv_nsec = attr->mtimensec, 258 }; 259 260 /* 261 * Auto inval mode also checks and invalidates if mtime 262 * has changed. 263 */ 264 if (!timespec64_equal(&old_mtime, &new_mtime)) 265 inval = true; 266 } 267 268 if (inval) 269 invalidate_inode_pages2(inode->i_mapping); 270 } 271 } 272 273 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr) 274 { 275 inode->i_mode = attr->mode & S_IFMT; 276 inode->i_size = attr->size; 277 inode->i_mtime.tv_sec = attr->mtime; 278 inode->i_mtime.tv_nsec = attr->mtimensec; 279 inode->i_ctime.tv_sec = attr->ctime; 280 inode->i_ctime.tv_nsec = attr->ctimensec; 281 if (S_ISREG(inode->i_mode)) { 282 fuse_init_common(inode); 283 fuse_init_file_inode(inode); 284 } else if (S_ISDIR(inode->i_mode)) 285 fuse_init_dir(inode); 286 else if (S_ISLNK(inode->i_mode)) 287 fuse_init_symlink(inode); 288 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 289 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 290 fuse_init_common(inode); 291 init_special_inode(inode, inode->i_mode, 292 new_decode_dev(attr->rdev)); 293 } else 294 BUG(); 295 } 296 297 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 298 { 299 u64 nodeid = *(u64 *) _nodeidp; 300 if (get_node_id(inode) == nodeid) 301 return 1; 302 else 303 return 0; 304 } 305 306 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 307 { 308 u64 nodeid = *(u64 *) _nodeidp; 309 get_fuse_inode(inode)->nodeid = nodeid; 310 return 0; 311 } 312 313 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 314 int generation, struct fuse_attr *attr, 315 u64 attr_valid, u64 attr_version) 316 { 317 struct inode *inode; 318 struct fuse_inode *fi; 319 struct fuse_conn *fc = get_fuse_conn_super(sb); 320 321 /* 322 * Auto mount points get their node id from the submount root, which is 323 * not a unique identifier within this filesystem. 324 * 325 * To avoid conflicts, do not place submount points into the inode hash 326 * table. 327 */ 328 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) && 329 S_ISDIR(attr->mode)) { 330 inode = new_inode(sb); 331 if (!inode) 332 return NULL; 333 334 fuse_init_inode(inode, attr); 335 get_fuse_inode(inode)->nodeid = nodeid; 336 inode->i_flags |= S_AUTOMOUNT; 337 goto done; 338 } 339 340 retry: 341 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 342 if (!inode) 343 return NULL; 344 345 if ((inode->i_state & I_NEW)) { 346 inode->i_flags |= S_NOATIME; 347 if (!fc->writeback_cache || !S_ISREG(attr->mode)) 348 inode->i_flags |= S_NOCMTIME; 349 inode->i_generation = generation; 350 fuse_init_inode(inode, attr); 351 unlock_new_inode(inode); 352 } else if (fuse_stale_inode(inode, generation, attr)) { 353 /* nodeid was reused, any I/O on the old inode should fail */ 354 fuse_make_bad(inode); 355 iput(inode); 356 goto retry; 357 } 358 done: 359 fi = get_fuse_inode(inode); 360 spin_lock(&fi->lock); 361 fi->nlookup++; 362 spin_unlock(&fi->lock); 363 fuse_change_attributes(inode, attr, attr_valid, attr_version); 364 365 return inode; 366 } 367 368 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid, 369 struct fuse_mount **fm) 370 { 371 struct fuse_mount *fm_iter; 372 struct inode *inode; 373 374 WARN_ON(!rwsem_is_locked(&fc->killsb)); 375 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) { 376 if (!fm_iter->sb) 377 continue; 378 379 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid); 380 if (inode) { 381 if (fm) 382 *fm = fm_iter; 383 return inode; 384 } 385 } 386 387 return NULL; 388 } 389 390 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid, 391 loff_t offset, loff_t len) 392 { 393 struct fuse_inode *fi; 394 struct inode *inode; 395 pgoff_t pg_start; 396 pgoff_t pg_end; 397 398 inode = fuse_ilookup(fc, nodeid, NULL); 399 if (!inode) 400 return -ENOENT; 401 402 fi = get_fuse_inode(inode); 403 spin_lock(&fi->lock); 404 fi->attr_version = atomic64_inc_return(&fc->attr_version); 405 spin_unlock(&fi->lock); 406 407 fuse_invalidate_attr(inode); 408 forget_all_cached_acls(inode); 409 if (offset >= 0) { 410 pg_start = offset >> PAGE_SHIFT; 411 if (len <= 0) 412 pg_end = -1; 413 else 414 pg_end = (offset + len - 1) >> PAGE_SHIFT; 415 invalidate_inode_pages2_range(inode->i_mapping, 416 pg_start, pg_end); 417 } 418 iput(inode); 419 return 0; 420 } 421 422 bool fuse_lock_inode(struct inode *inode) 423 { 424 bool locked = false; 425 426 if (!get_fuse_conn(inode)->parallel_dirops) { 427 mutex_lock(&get_fuse_inode(inode)->mutex); 428 locked = true; 429 } 430 431 return locked; 432 } 433 434 void fuse_unlock_inode(struct inode *inode, bool locked) 435 { 436 if (locked) 437 mutex_unlock(&get_fuse_inode(inode)->mutex); 438 } 439 440 static void fuse_umount_begin(struct super_block *sb) 441 { 442 struct fuse_conn *fc = get_fuse_conn_super(sb); 443 444 if (!fc->no_force_umount) 445 fuse_abort_conn(fc); 446 } 447 448 static void fuse_send_destroy(struct fuse_mount *fm) 449 { 450 if (fm->fc->conn_init) { 451 FUSE_ARGS(args); 452 453 args.opcode = FUSE_DESTROY; 454 args.force = true; 455 args.nocreds = true; 456 fuse_simple_request(fm, &args); 457 } 458 } 459 460 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 461 { 462 stbuf->f_type = FUSE_SUPER_MAGIC; 463 stbuf->f_bsize = attr->bsize; 464 stbuf->f_frsize = attr->frsize; 465 stbuf->f_blocks = attr->blocks; 466 stbuf->f_bfree = attr->bfree; 467 stbuf->f_bavail = attr->bavail; 468 stbuf->f_files = attr->files; 469 stbuf->f_ffree = attr->ffree; 470 stbuf->f_namelen = attr->namelen; 471 /* fsid is left zero */ 472 } 473 474 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 475 { 476 struct super_block *sb = dentry->d_sb; 477 struct fuse_mount *fm = get_fuse_mount_super(sb); 478 FUSE_ARGS(args); 479 struct fuse_statfs_out outarg; 480 int err; 481 482 if (!fuse_allow_current_process(fm->fc)) { 483 buf->f_type = FUSE_SUPER_MAGIC; 484 return 0; 485 } 486 487 memset(&outarg, 0, sizeof(outarg)); 488 args.in_numargs = 0; 489 args.opcode = FUSE_STATFS; 490 args.nodeid = get_node_id(d_inode(dentry)); 491 args.out_numargs = 1; 492 args.out_args[0].size = sizeof(outarg); 493 args.out_args[0].value = &outarg; 494 err = fuse_simple_request(fm, &args); 495 if (!err) 496 convert_fuse_statfs(buf, &outarg.st); 497 return err; 498 } 499 500 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void) 501 { 502 struct fuse_sync_bucket *bucket; 503 504 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL); 505 if (bucket) { 506 init_waitqueue_head(&bucket->waitq); 507 /* Initial active count */ 508 atomic_set(&bucket->count, 1); 509 } 510 return bucket; 511 } 512 513 static void fuse_sync_fs_writes(struct fuse_conn *fc) 514 { 515 struct fuse_sync_bucket *bucket, *new_bucket; 516 int count; 517 518 new_bucket = fuse_sync_bucket_alloc(); 519 spin_lock(&fc->lock); 520 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 521 count = atomic_read(&bucket->count); 522 WARN_ON(count < 1); 523 /* No outstanding writes? */ 524 if (count == 1) { 525 spin_unlock(&fc->lock); 526 kfree(new_bucket); 527 return; 528 } 529 530 /* 531 * Completion of new bucket depends on completion of this bucket, so add 532 * one more count. 533 */ 534 atomic_inc(&new_bucket->count); 535 rcu_assign_pointer(fc->curr_bucket, new_bucket); 536 spin_unlock(&fc->lock); 537 /* 538 * Drop initial active count. At this point if all writes in this and 539 * ancestor buckets complete, the count will go to zero and this task 540 * will be woken up. 541 */ 542 atomic_dec(&bucket->count); 543 544 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0); 545 546 /* Drop temp count on descendant bucket */ 547 fuse_sync_bucket_dec(new_bucket); 548 kfree_rcu(bucket, rcu); 549 } 550 551 static int fuse_sync_fs(struct super_block *sb, int wait) 552 { 553 struct fuse_mount *fm = get_fuse_mount_super(sb); 554 struct fuse_conn *fc = fm->fc; 555 struct fuse_syncfs_in inarg; 556 FUSE_ARGS(args); 557 int err; 558 559 /* 560 * Userspace cannot handle the wait == 0 case. Avoid a 561 * gratuitous roundtrip. 562 */ 563 if (!wait) 564 return 0; 565 566 /* The filesystem is being unmounted. Nothing to do. */ 567 if (!sb->s_root) 568 return 0; 569 570 if (!fc->sync_fs) 571 return 0; 572 573 fuse_sync_fs_writes(fc); 574 575 memset(&inarg, 0, sizeof(inarg)); 576 args.in_numargs = 1; 577 args.in_args[0].size = sizeof(inarg); 578 args.in_args[0].value = &inarg; 579 args.opcode = FUSE_SYNCFS; 580 args.nodeid = get_node_id(sb->s_root->d_inode); 581 args.out_numargs = 0; 582 583 err = fuse_simple_request(fm, &args); 584 if (err == -ENOSYS) { 585 fc->sync_fs = 0; 586 err = 0; 587 } 588 589 return err; 590 } 591 592 enum { 593 OPT_SOURCE, 594 OPT_SUBTYPE, 595 OPT_FD, 596 OPT_ROOTMODE, 597 OPT_USER_ID, 598 OPT_GROUP_ID, 599 OPT_DEFAULT_PERMISSIONS, 600 OPT_ALLOW_OTHER, 601 OPT_MAX_READ, 602 OPT_BLKSIZE, 603 OPT_ERR 604 }; 605 606 static const struct fs_parameter_spec fuse_fs_parameters[] = { 607 fsparam_string ("source", OPT_SOURCE), 608 fsparam_u32 ("fd", OPT_FD), 609 fsparam_u32oct ("rootmode", OPT_ROOTMODE), 610 fsparam_u32 ("user_id", OPT_USER_ID), 611 fsparam_u32 ("group_id", OPT_GROUP_ID), 612 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS), 613 fsparam_flag ("allow_other", OPT_ALLOW_OTHER), 614 fsparam_u32 ("max_read", OPT_MAX_READ), 615 fsparam_u32 ("blksize", OPT_BLKSIZE), 616 fsparam_string ("subtype", OPT_SUBTYPE), 617 {} 618 }; 619 620 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param) 621 { 622 struct fs_parse_result result; 623 struct fuse_fs_context *ctx = fsc->fs_private; 624 int opt; 625 626 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { 627 /* 628 * Ignore options coming from mount(MS_REMOUNT) for backward 629 * compatibility. 630 */ 631 if (fsc->oldapi) 632 return 0; 633 634 return invalfc(fsc, "No changes allowed in reconfigure"); 635 } 636 637 opt = fs_parse(fsc, fuse_fs_parameters, param, &result); 638 if (opt < 0) 639 return opt; 640 641 switch (opt) { 642 case OPT_SOURCE: 643 if (fsc->source) 644 return invalfc(fsc, "Multiple sources specified"); 645 fsc->source = param->string; 646 param->string = NULL; 647 break; 648 649 case OPT_SUBTYPE: 650 if (ctx->subtype) 651 return invalfc(fsc, "Multiple subtypes specified"); 652 ctx->subtype = param->string; 653 param->string = NULL; 654 return 0; 655 656 case OPT_FD: 657 ctx->fd = result.uint_32; 658 ctx->fd_present = true; 659 break; 660 661 case OPT_ROOTMODE: 662 if (!fuse_valid_type(result.uint_32)) 663 return invalfc(fsc, "Invalid rootmode"); 664 ctx->rootmode = result.uint_32; 665 ctx->rootmode_present = true; 666 break; 667 668 case OPT_USER_ID: 669 ctx->user_id = make_kuid(fsc->user_ns, result.uint_32); 670 if (!uid_valid(ctx->user_id)) 671 return invalfc(fsc, "Invalid user_id"); 672 ctx->user_id_present = true; 673 break; 674 675 case OPT_GROUP_ID: 676 ctx->group_id = make_kgid(fsc->user_ns, result.uint_32); 677 if (!gid_valid(ctx->group_id)) 678 return invalfc(fsc, "Invalid group_id"); 679 ctx->group_id_present = true; 680 break; 681 682 case OPT_DEFAULT_PERMISSIONS: 683 ctx->default_permissions = true; 684 break; 685 686 case OPT_ALLOW_OTHER: 687 ctx->allow_other = true; 688 break; 689 690 case OPT_MAX_READ: 691 ctx->max_read = result.uint_32; 692 break; 693 694 case OPT_BLKSIZE: 695 if (!ctx->is_bdev) 696 return invalfc(fsc, "blksize only supported for fuseblk"); 697 ctx->blksize = result.uint_32; 698 break; 699 700 default: 701 return -EINVAL; 702 } 703 704 return 0; 705 } 706 707 static void fuse_free_fsc(struct fs_context *fsc) 708 { 709 struct fuse_fs_context *ctx = fsc->fs_private; 710 711 if (ctx) { 712 kfree(ctx->subtype); 713 kfree(ctx); 714 } 715 } 716 717 static int fuse_show_options(struct seq_file *m, struct dentry *root) 718 { 719 struct super_block *sb = root->d_sb; 720 struct fuse_conn *fc = get_fuse_conn_super(sb); 721 722 if (fc->legacy_opts_show) { 723 seq_printf(m, ",user_id=%u", 724 from_kuid_munged(fc->user_ns, fc->user_id)); 725 seq_printf(m, ",group_id=%u", 726 from_kgid_munged(fc->user_ns, fc->group_id)); 727 if (fc->default_permissions) 728 seq_puts(m, ",default_permissions"); 729 if (fc->allow_other) 730 seq_puts(m, ",allow_other"); 731 if (fc->max_read != ~0) 732 seq_printf(m, ",max_read=%u", fc->max_read); 733 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 734 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 735 } 736 #ifdef CONFIG_FUSE_DAX 737 if (fc->dax) 738 seq_puts(m, ",dax"); 739 #endif 740 741 return 0; 742 } 743 744 static void fuse_iqueue_init(struct fuse_iqueue *fiq, 745 const struct fuse_iqueue_ops *ops, 746 void *priv) 747 { 748 memset(fiq, 0, sizeof(struct fuse_iqueue)); 749 spin_lock_init(&fiq->lock); 750 init_waitqueue_head(&fiq->waitq); 751 INIT_LIST_HEAD(&fiq->pending); 752 INIT_LIST_HEAD(&fiq->interrupts); 753 fiq->forget_list_tail = &fiq->forget_list_head; 754 fiq->connected = 1; 755 fiq->ops = ops; 756 fiq->priv = priv; 757 } 758 759 static void fuse_pqueue_init(struct fuse_pqueue *fpq) 760 { 761 unsigned int i; 762 763 spin_lock_init(&fpq->lock); 764 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 765 INIT_LIST_HEAD(&fpq->processing[i]); 766 INIT_LIST_HEAD(&fpq->io); 767 fpq->connected = 1; 768 } 769 770 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, 771 struct user_namespace *user_ns, 772 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv) 773 { 774 memset(fc, 0, sizeof(*fc)); 775 spin_lock_init(&fc->lock); 776 spin_lock_init(&fc->bg_lock); 777 init_rwsem(&fc->killsb); 778 refcount_set(&fc->count, 1); 779 atomic_set(&fc->dev_count, 1); 780 init_waitqueue_head(&fc->blocked_waitq); 781 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv); 782 INIT_LIST_HEAD(&fc->bg_queue); 783 INIT_LIST_HEAD(&fc->entry); 784 INIT_LIST_HEAD(&fc->devices); 785 atomic_set(&fc->num_waiting, 0); 786 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 787 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 788 atomic64_set(&fc->khctr, 0); 789 fc->polled_files = RB_ROOT; 790 fc->blocked = 0; 791 fc->initialized = 0; 792 fc->connected = 1; 793 atomic64_set(&fc->attr_version, 1); 794 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 795 fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); 796 fc->user_ns = get_user_ns(user_ns); 797 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; 798 fc->max_pages_limit = FUSE_MAX_MAX_PAGES; 799 800 INIT_LIST_HEAD(&fc->mounts); 801 list_add(&fm->fc_entry, &fc->mounts); 802 fm->fc = fc; 803 } 804 EXPORT_SYMBOL_GPL(fuse_conn_init); 805 806 void fuse_conn_put(struct fuse_conn *fc) 807 { 808 if (refcount_dec_and_test(&fc->count)) { 809 struct fuse_iqueue *fiq = &fc->iq; 810 struct fuse_sync_bucket *bucket; 811 812 if (IS_ENABLED(CONFIG_FUSE_DAX)) 813 fuse_dax_conn_free(fc); 814 if (fiq->ops->release) 815 fiq->ops->release(fiq); 816 put_pid_ns(fc->pid_ns); 817 put_user_ns(fc->user_ns); 818 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 819 if (bucket) { 820 WARN_ON(atomic_read(&bucket->count) != 1); 821 kfree(bucket); 822 } 823 fc->release(fc); 824 } 825 } 826 EXPORT_SYMBOL_GPL(fuse_conn_put); 827 828 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 829 { 830 refcount_inc(&fc->count); 831 return fc; 832 } 833 EXPORT_SYMBOL_GPL(fuse_conn_get); 834 835 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 836 { 837 struct fuse_attr attr; 838 memset(&attr, 0, sizeof(attr)); 839 840 attr.mode = mode; 841 attr.ino = FUSE_ROOT_ID; 842 attr.nlink = 1; 843 return fuse_iget(sb, 1, 0, &attr, 0, 0); 844 } 845 846 struct fuse_inode_handle { 847 u64 nodeid; 848 u32 generation; 849 }; 850 851 static struct dentry *fuse_get_dentry(struct super_block *sb, 852 struct fuse_inode_handle *handle) 853 { 854 struct fuse_conn *fc = get_fuse_conn_super(sb); 855 struct inode *inode; 856 struct dentry *entry; 857 int err = -ESTALE; 858 859 if (handle->nodeid == 0) 860 goto out_err; 861 862 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 863 if (!inode) { 864 struct fuse_entry_out outarg; 865 const struct qstr name = QSTR_INIT(".", 1); 866 867 if (!fc->export_support) 868 goto out_err; 869 870 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 871 &inode); 872 if (err && err != -ENOENT) 873 goto out_err; 874 if (err || !inode) { 875 err = -ESTALE; 876 goto out_err; 877 } 878 err = -EIO; 879 if (get_node_id(inode) != handle->nodeid) 880 goto out_iput; 881 } 882 err = -ESTALE; 883 if (inode->i_generation != handle->generation) 884 goto out_iput; 885 886 entry = d_obtain_alias(inode); 887 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 888 fuse_invalidate_entry_cache(entry); 889 890 return entry; 891 892 out_iput: 893 iput(inode); 894 out_err: 895 return ERR_PTR(err); 896 } 897 898 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 899 struct inode *parent) 900 { 901 int len = parent ? 6 : 3; 902 u64 nodeid; 903 u32 generation; 904 905 if (*max_len < len) { 906 *max_len = len; 907 return FILEID_INVALID; 908 } 909 910 nodeid = get_fuse_inode(inode)->nodeid; 911 generation = inode->i_generation; 912 913 fh[0] = (u32)(nodeid >> 32); 914 fh[1] = (u32)(nodeid & 0xffffffff); 915 fh[2] = generation; 916 917 if (parent) { 918 nodeid = get_fuse_inode(parent)->nodeid; 919 generation = parent->i_generation; 920 921 fh[3] = (u32)(nodeid >> 32); 922 fh[4] = (u32)(nodeid & 0xffffffff); 923 fh[5] = generation; 924 } 925 926 *max_len = len; 927 return parent ? 0x82 : 0x81; 928 } 929 930 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 931 struct fid *fid, int fh_len, int fh_type) 932 { 933 struct fuse_inode_handle handle; 934 935 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 936 return NULL; 937 938 handle.nodeid = (u64) fid->raw[0] << 32; 939 handle.nodeid |= (u64) fid->raw[1]; 940 handle.generation = fid->raw[2]; 941 return fuse_get_dentry(sb, &handle); 942 } 943 944 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 945 struct fid *fid, int fh_len, int fh_type) 946 { 947 struct fuse_inode_handle parent; 948 949 if (fh_type != 0x82 || fh_len < 6) 950 return NULL; 951 952 parent.nodeid = (u64) fid->raw[3] << 32; 953 parent.nodeid |= (u64) fid->raw[4]; 954 parent.generation = fid->raw[5]; 955 return fuse_get_dentry(sb, &parent); 956 } 957 958 static struct dentry *fuse_get_parent(struct dentry *child) 959 { 960 struct inode *child_inode = d_inode(child); 961 struct fuse_conn *fc = get_fuse_conn(child_inode); 962 struct inode *inode; 963 struct dentry *parent; 964 struct fuse_entry_out outarg; 965 int err; 966 967 if (!fc->export_support) 968 return ERR_PTR(-ESTALE); 969 970 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 971 &dotdot_name, &outarg, &inode); 972 if (err) { 973 if (err == -ENOENT) 974 return ERR_PTR(-ESTALE); 975 return ERR_PTR(err); 976 } 977 978 parent = d_obtain_alias(inode); 979 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 980 fuse_invalidate_entry_cache(parent); 981 982 return parent; 983 } 984 985 static const struct export_operations fuse_export_operations = { 986 .fh_to_dentry = fuse_fh_to_dentry, 987 .fh_to_parent = fuse_fh_to_parent, 988 .encode_fh = fuse_encode_fh, 989 .get_parent = fuse_get_parent, 990 }; 991 992 static const struct super_operations fuse_super_operations = { 993 .alloc_inode = fuse_alloc_inode, 994 .free_inode = fuse_free_inode, 995 .evict_inode = fuse_evict_inode, 996 .write_inode = fuse_write_inode, 997 .drop_inode = generic_delete_inode, 998 .umount_begin = fuse_umount_begin, 999 .statfs = fuse_statfs, 1000 .sync_fs = fuse_sync_fs, 1001 .show_options = fuse_show_options, 1002 }; 1003 1004 static void sanitize_global_limit(unsigned *limit) 1005 { 1006 /* 1007 * The default maximum number of async requests is calculated to consume 1008 * 1/2^13 of the total memory, assuming 392 bytes per request. 1009 */ 1010 if (*limit == 0) 1011 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392; 1012 1013 if (*limit >= 1 << 16) 1014 *limit = (1 << 16) - 1; 1015 } 1016 1017 static int set_global_limit(const char *val, const struct kernel_param *kp) 1018 { 1019 int rv; 1020 1021 rv = param_set_uint(val, kp); 1022 if (rv) 1023 return rv; 1024 1025 sanitize_global_limit((unsigned *)kp->arg); 1026 1027 return 0; 1028 } 1029 1030 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 1031 { 1032 int cap_sys_admin = capable(CAP_SYS_ADMIN); 1033 1034 if (arg->minor < 13) 1035 return; 1036 1037 sanitize_global_limit(&max_user_bgreq); 1038 sanitize_global_limit(&max_user_congthresh); 1039 1040 spin_lock(&fc->bg_lock); 1041 if (arg->max_background) { 1042 fc->max_background = arg->max_background; 1043 1044 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 1045 fc->max_background = max_user_bgreq; 1046 } 1047 if (arg->congestion_threshold) { 1048 fc->congestion_threshold = arg->congestion_threshold; 1049 1050 if (!cap_sys_admin && 1051 fc->congestion_threshold > max_user_congthresh) 1052 fc->congestion_threshold = max_user_congthresh; 1053 } 1054 spin_unlock(&fc->bg_lock); 1055 } 1056 1057 struct fuse_init_args { 1058 struct fuse_args args; 1059 struct fuse_init_in in; 1060 struct fuse_init_out out; 1061 }; 1062 1063 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, 1064 int error) 1065 { 1066 struct fuse_conn *fc = fm->fc; 1067 struct fuse_init_args *ia = container_of(args, typeof(*ia), args); 1068 struct fuse_init_out *arg = &ia->out; 1069 bool ok = true; 1070 1071 if (error || arg->major != FUSE_KERNEL_VERSION) 1072 ok = false; 1073 else { 1074 unsigned long ra_pages; 1075 1076 process_init_limits(fc, arg); 1077 1078 if (arg->minor >= 6) { 1079 ra_pages = arg->max_readahead / PAGE_SIZE; 1080 if (arg->flags & FUSE_ASYNC_READ) 1081 fc->async_read = 1; 1082 if (!(arg->flags & FUSE_POSIX_LOCKS)) 1083 fc->no_lock = 1; 1084 if (arg->minor >= 17) { 1085 if (!(arg->flags & FUSE_FLOCK_LOCKS)) 1086 fc->no_flock = 1; 1087 } else { 1088 if (!(arg->flags & FUSE_POSIX_LOCKS)) 1089 fc->no_flock = 1; 1090 } 1091 if (arg->flags & FUSE_ATOMIC_O_TRUNC) 1092 fc->atomic_o_trunc = 1; 1093 if (arg->minor >= 9) { 1094 /* LOOKUP has dependency on proto version */ 1095 if (arg->flags & FUSE_EXPORT_SUPPORT) 1096 fc->export_support = 1; 1097 } 1098 if (arg->flags & FUSE_BIG_WRITES) 1099 fc->big_writes = 1; 1100 if (arg->flags & FUSE_DONT_MASK) 1101 fc->dont_mask = 1; 1102 if (arg->flags & FUSE_AUTO_INVAL_DATA) 1103 fc->auto_inval_data = 1; 1104 else if (arg->flags & FUSE_EXPLICIT_INVAL_DATA) 1105 fc->explicit_inval_data = 1; 1106 if (arg->flags & FUSE_DO_READDIRPLUS) { 1107 fc->do_readdirplus = 1; 1108 if (arg->flags & FUSE_READDIRPLUS_AUTO) 1109 fc->readdirplus_auto = 1; 1110 } 1111 if (arg->flags & FUSE_ASYNC_DIO) 1112 fc->async_dio = 1; 1113 if (arg->flags & FUSE_WRITEBACK_CACHE) 1114 fc->writeback_cache = 1; 1115 if (arg->flags & FUSE_PARALLEL_DIROPS) 1116 fc->parallel_dirops = 1; 1117 if (arg->flags & FUSE_HANDLE_KILLPRIV) 1118 fc->handle_killpriv = 1; 1119 if (arg->time_gran && arg->time_gran <= 1000000000) 1120 fm->sb->s_time_gran = arg->time_gran; 1121 if ((arg->flags & FUSE_POSIX_ACL)) { 1122 fc->default_permissions = 1; 1123 fc->posix_acl = 1; 1124 fm->sb->s_xattr = fuse_acl_xattr_handlers; 1125 } 1126 if (arg->flags & FUSE_CACHE_SYMLINKS) 1127 fc->cache_symlinks = 1; 1128 if (arg->flags & FUSE_ABORT_ERROR) 1129 fc->abort_err = 1; 1130 if (arg->flags & FUSE_MAX_PAGES) { 1131 fc->max_pages = 1132 min_t(unsigned int, fc->max_pages_limit, 1133 max_t(unsigned int, arg->max_pages, 1)); 1134 } 1135 if (IS_ENABLED(CONFIG_FUSE_DAX) && 1136 arg->flags & FUSE_MAP_ALIGNMENT && 1137 !fuse_dax_check_alignment(fc, arg->map_alignment)) { 1138 ok = false; 1139 } 1140 if (arg->flags & FUSE_HANDLE_KILLPRIV_V2) { 1141 fc->handle_killpriv_v2 = 1; 1142 fm->sb->s_flags |= SB_NOSEC; 1143 } 1144 if (arg->flags & FUSE_SETXATTR_EXT) 1145 fc->setxattr_ext = 1; 1146 } else { 1147 ra_pages = fc->max_read / PAGE_SIZE; 1148 fc->no_lock = 1; 1149 fc->no_flock = 1; 1150 } 1151 1152 fm->sb->s_bdi->ra_pages = 1153 min(fm->sb->s_bdi->ra_pages, ra_pages); 1154 fc->minor = arg->minor; 1155 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 1156 fc->max_write = max_t(unsigned, 4096, fc->max_write); 1157 fc->conn_init = 1; 1158 } 1159 kfree(ia); 1160 1161 if (!ok) { 1162 fc->conn_init = 0; 1163 fc->conn_error = 1; 1164 } 1165 1166 fuse_set_initialized(fc); 1167 wake_up_all(&fc->blocked_waitq); 1168 } 1169 1170 void fuse_send_init(struct fuse_mount *fm) 1171 { 1172 struct fuse_init_args *ia; 1173 1174 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL); 1175 1176 ia->in.major = FUSE_KERNEL_VERSION; 1177 ia->in.minor = FUSE_KERNEL_MINOR_VERSION; 1178 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE; 1179 ia->in.flags |= 1180 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 1181 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 1182 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 1183 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 1184 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 1185 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | 1186 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL | 1187 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS | 1188 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | 1189 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT; 1190 #ifdef CONFIG_FUSE_DAX 1191 if (fm->fc->dax) 1192 ia->in.flags |= FUSE_MAP_ALIGNMENT; 1193 #endif 1194 if (fm->fc->auto_submounts) 1195 ia->in.flags |= FUSE_SUBMOUNTS; 1196 1197 ia->args.opcode = FUSE_INIT; 1198 ia->args.in_numargs = 1; 1199 ia->args.in_args[0].size = sizeof(ia->in); 1200 ia->args.in_args[0].value = &ia->in; 1201 ia->args.out_numargs = 1; 1202 /* Variable length argument used for backward compatibility 1203 with interface version < 7.5. Rest of init_out is zeroed 1204 by do_get_request(), so a short reply is not a problem */ 1205 ia->args.out_argvar = true; 1206 ia->args.out_args[0].size = sizeof(ia->out); 1207 ia->args.out_args[0].value = &ia->out; 1208 ia->args.force = true; 1209 ia->args.nocreds = true; 1210 ia->args.end = process_init_reply; 1211 1212 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0) 1213 process_init_reply(fm, &ia->args, -ENOTCONN); 1214 } 1215 EXPORT_SYMBOL_GPL(fuse_send_init); 1216 1217 void fuse_free_conn(struct fuse_conn *fc) 1218 { 1219 WARN_ON(!list_empty(&fc->devices)); 1220 kfree_rcu(fc, rcu); 1221 } 1222 EXPORT_SYMBOL_GPL(fuse_free_conn); 1223 1224 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 1225 { 1226 int err; 1227 char *suffix = ""; 1228 1229 if (sb->s_bdev) { 1230 suffix = "-fuseblk"; 1231 /* 1232 * sb->s_bdi points to blkdev's bdi however we want to redirect 1233 * it to our private bdi... 1234 */ 1235 bdi_put(sb->s_bdi); 1236 sb->s_bdi = &noop_backing_dev_info; 1237 } 1238 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev), 1239 MINOR(fc->dev), suffix); 1240 if (err) 1241 return err; 1242 1243 /* fuse does it's own writeback accounting */ 1244 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT; 1245 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT; 1246 1247 /* 1248 * For a single fuse filesystem use max 1% of dirty + 1249 * writeback threshold. 1250 * 1251 * This gives about 1M of write buffer for memory maps on a 1252 * machine with 1G and 10% dirty_ratio, which should be more 1253 * than enough. 1254 * 1255 * Privileged users can raise it by writing to 1256 * 1257 * /sys/class/bdi/<bdi>/max_ratio 1258 */ 1259 bdi_set_max_ratio(sb->s_bdi, 1); 1260 1261 return 0; 1262 } 1263 1264 struct fuse_dev *fuse_dev_alloc(void) 1265 { 1266 struct fuse_dev *fud; 1267 struct list_head *pq; 1268 1269 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); 1270 if (!fud) 1271 return NULL; 1272 1273 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL); 1274 if (!pq) { 1275 kfree(fud); 1276 return NULL; 1277 } 1278 1279 fud->pq.processing = pq; 1280 fuse_pqueue_init(&fud->pq); 1281 1282 return fud; 1283 } 1284 EXPORT_SYMBOL_GPL(fuse_dev_alloc); 1285 1286 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) 1287 { 1288 fud->fc = fuse_conn_get(fc); 1289 spin_lock(&fc->lock); 1290 list_add_tail(&fud->entry, &fc->devices); 1291 spin_unlock(&fc->lock); 1292 } 1293 EXPORT_SYMBOL_GPL(fuse_dev_install); 1294 1295 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) 1296 { 1297 struct fuse_dev *fud; 1298 1299 fud = fuse_dev_alloc(); 1300 if (!fud) 1301 return NULL; 1302 1303 fuse_dev_install(fud, fc); 1304 return fud; 1305 } 1306 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); 1307 1308 void fuse_dev_free(struct fuse_dev *fud) 1309 { 1310 struct fuse_conn *fc = fud->fc; 1311 1312 if (fc) { 1313 spin_lock(&fc->lock); 1314 list_del(&fud->entry); 1315 spin_unlock(&fc->lock); 1316 1317 fuse_conn_put(fc); 1318 } 1319 kfree(fud->pq.processing); 1320 kfree(fud); 1321 } 1322 EXPORT_SYMBOL_GPL(fuse_dev_free); 1323 1324 static void fuse_fill_attr_from_inode(struct fuse_attr *attr, 1325 const struct fuse_inode *fi) 1326 { 1327 *attr = (struct fuse_attr){ 1328 .ino = fi->inode.i_ino, 1329 .size = fi->inode.i_size, 1330 .blocks = fi->inode.i_blocks, 1331 .atime = fi->inode.i_atime.tv_sec, 1332 .mtime = fi->inode.i_mtime.tv_sec, 1333 .ctime = fi->inode.i_ctime.tv_sec, 1334 .atimensec = fi->inode.i_atime.tv_nsec, 1335 .mtimensec = fi->inode.i_mtime.tv_nsec, 1336 .ctimensec = fi->inode.i_ctime.tv_nsec, 1337 .mode = fi->inode.i_mode, 1338 .nlink = fi->inode.i_nlink, 1339 .uid = fi->inode.i_uid.val, 1340 .gid = fi->inode.i_gid.val, 1341 .rdev = fi->inode.i_rdev, 1342 .blksize = 1u << fi->inode.i_blkbits, 1343 }; 1344 } 1345 1346 static void fuse_sb_defaults(struct super_block *sb) 1347 { 1348 sb->s_magic = FUSE_SUPER_MAGIC; 1349 sb->s_op = &fuse_super_operations; 1350 sb->s_xattr = fuse_xattr_handlers; 1351 sb->s_maxbytes = MAX_LFS_FILESIZE; 1352 sb->s_time_gran = 1; 1353 sb->s_export_op = &fuse_export_operations; 1354 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; 1355 if (sb->s_user_ns != &init_user_ns) 1356 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; 1357 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); 1358 1359 /* 1360 * If we are not in the initial user namespace posix 1361 * acls must be translated. 1362 */ 1363 if (sb->s_user_ns != &init_user_ns) 1364 sb->s_xattr = fuse_no_acl_xattr_handlers; 1365 } 1366 1367 static int fuse_fill_super_submount(struct super_block *sb, 1368 struct fuse_inode *parent_fi) 1369 { 1370 struct fuse_mount *fm = get_fuse_mount_super(sb); 1371 struct super_block *parent_sb = parent_fi->inode.i_sb; 1372 struct fuse_attr root_attr; 1373 struct inode *root; 1374 1375 fuse_sb_defaults(sb); 1376 fm->sb = sb; 1377 1378 WARN_ON(sb->s_bdi != &noop_backing_dev_info); 1379 sb->s_bdi = bdi_get(parent_sb->s_bdi); 1380 1381 sb->s_xattr = parent_sb->s_xattr; 1382 sb->s_time_gran = parent_sb->s_time_gran; 1383 sb->s_blocksize = parent_sb->s_blocksize; 1384 sb->s_blocksize_bits = parent_sb->s_blocksize_bits; 1385 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL); 1386 if (parent_sb->s_subtype && !sb->s_subtype) 1387 return -ENOMEM; 1388 1389 fuse_fill_attr_from_inode(&root_attr, parent_fi); 1390 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0); 1391 /* 1392 * This inode is just a duplicate, so it is not looked up and 1393 * its nlookup should not be incremented. fuse_iget() does 1394 * that, though, so undo it here. 1395 */ 1396 get_fuse_inode(root)->nlookup--; 1397 sb->s_d_op = &fuse_dentry_operations; 1398 sb->s_root = d_make_root(root); 1399 if (!sb->s_root) 1400 return -ENOMEM; 1401 1402 return 0; 1403 } 1404 1405 /* Filesystem context private data holds the FUSE inode of the mount point */ 1406 static int fuse_get_tree_submount(struct fs_context *fsc) 1407 { 1408 struct fuse_mount *fm; 1409 struct fuse_inode *mp_fi = fsc->fs_private; 1410 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); 1411 struct super_block *sb; 1412 int err; 1413 1414 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); 1415 if (!fm) 1416 return -ENOMEM; 1417 1418 fm->fc = fuse_conn_get(fc); 1419 fsc->s_fs_info = fm; 1420 sb = sget_fc(fsc, NULL, set_anon_super_fc); 1421 if (fsc->s_fs_info) 1422 fuse_mount_destroy(fm); 1423 if (IS_ERR(sb)) 1424 return PTR_ERR(sb); 1425 1426 /* Initialize superblock, making @mp_fi its root */ 1427 err = fuse_fill_super_submount(sb, mp_fi); 1428 if (err) { 1429 deactivate_locked_super(sb); 1430 return err; 1431 } 1432 1433 down_write(&fc->killsb); 1434 list_add_tail(&fm->fc_entry, &fc->mounts); 1435 up_write(&fc->killsb); 1436 1437 sb->s_flags |= SB_ACTIVE; 1438 fsc->root = dget(sb->s_root); 1439 1440 return 0; 1441 } 1442 1443 static const struct fs_context_operations fuse_context_submount_ops = { 1444 .get_tree = fuse_get_tree_submount, 1445 }; 1446 1447 int fuse_init_fs_context_submount(struct fs_context *fsc) 1448 { 1449 fsc->ops = &fuse_context_submount_ops; 1450 return 0; 1451 } 1452 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); 1453 1454 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 1455 { 1456 struct fuse_dev *fud = NULL; 1457 struct fuse_mount *fm = get_fuse_mount_super(sb); 1458 struct fuse_conn *fc = fm->fc; 1459 struct inode *root; 1460 struct dentry *root_dentry; 1461 int err; 1462 1463 err = -EINVAL; 1464 if (sb->s_flags & SB_MANDLOCK) 1465 goto err; 1466 1467 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc()); 1468 fuse_sb_defaults(sb); 1469 1470 if (ctx->is_bdev) { 1471 #ifdef CONFIG_BLOCK 1472 err = -EINVAL; 1473 if (!sb_set_blocksize(sb, ctx->blksize)) 1474 goto err; 1475 #endif 1476 } else { 1477 sb->s_blocksize = PAGE_SIZE; 1478 sb->s_blocksize_bits = PAGE_SHIFT; 1479 } 1480 1481 sb->s_subtype = ctx->subtype; 1482 ctx->subtype = NULL; 1483 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1484 err = fuse_dax_conn_alloc(fc, ctx->dax_dev); 1485 if (err) 1486 goto err; 1487 } 1488 1489 if (ctx->fudptr) { 1490 err = -ENOMEM; 1491 fud = fuse_dev_alloc_install(fc); 1492 if (!fud) 1493 goto err_free_dax; 1494 } 1495 1496 fc->dev = sb->s_dev; 1497 fm->sb = sb; 1498 err = fuse_bdi_init(fc, sb); 1499 if (err) 1500 goto err_dev_free; 1501 1502 /* Handle umasking inside the fuse code */ 1503 if (sb->s_flags & SB_POSIXACL) 1504 fc->dont_mask = 1; 1505 sb->s_flags |= SB_POSIXACL; 1506 1507 fc->default_permissions = ctx->default_permissions; 1508 fc->allow_other = ctx->allow_other; 1509 fc->user_id = ctx->user_id; 1510 fc->group_id = ctx->group_id; 1511 fc->legacy_opts_show = ctx->legacy_opts_show; 1512 fc->max_read = max_t(unsigned int, 4096, ctx->max_read); 1513 fc->destroy = ctx->destroy; 1514 fc->no_control = ctx->no_control; 1515 fc->no_force_umount = ctx->no_force_umount; 1516 1517 err = -ENOMEM; 1518 root = fuse_get_root_inode(sb, ctx->rootmode); 1519 sb->s_d_op = &fuse_root_dentry_operations; 1520 root_dentry = d_make_root(root); 1521 if (!root_dentry) 1522 goto err_dev_free; 1523 /* Root dentry doesn't have .d_revalidate */ 1524 sb->s_d_op = &fuse_dentry_operations; 1525 1526 mutex_lock(&fuse_mutex); 1527 err = -EINVAL; 1528 if (ctx->fudptr && *ctx->fudptr) 1529 goto err_unlock; 1530 1531 err = fuse_ctl_add_conn(fc); 1532 if (err) 1533 goto err_unlock; 1534 1535 list_add_tail(&fc->entry, &fuse_conn_list); 1536 sb->s_root = root_dentry; 1537 if (ctx->fudptr) 1538 *ctx->fudptr = fud; 1539 mutex_unlock(&fuse_mutex); 1540 return 0; 1541 1542 err_unlock: 1543 mutex_unlock(&fuse_mutex); 1544 dput(root_dentry); 1545 err_dev_free: 1546 if (fud) 1547 fuse_dev_free(fud); 1548 err_free_dax: 1549 if (IS_ENABLED(CONFIG_FUSE_DAX)) 1550 fuse_dax_conn_free(fc); 1551 err: 1552 return err; 1553 } 1554 EXPORT_SYMBOL_GPL(fuse_fill_super_common); 1555 1556 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 1557 { 1558 struct fuse_fs_context *ctx = fsc->fs_private; 1559 int err; 1560 1561 if (!ctx->file || !ctx->rootmode_present || 1562 !ctx->user_id_present || !ctx->group_id_present) 1563 return -EINVAL; 1564 1565 /* 1566 * Require mount to happen from the same user namespace which 1567 * opened /dev/fuse to prevent potential attacks. 1568 */ 1569 if ((ctx->file->f_op != &fuse_dev_operations) || 1570 (ctx->file->f_cred->user_ns != sb->s_user_ns)) 1571 return -EINVAL; 1572 ctx->fudptr = &ctx->file->private_data; 1573 1574 err = fuse_fill_super_common(sb, ctx); 1575 if (err) 1576 return err; 1577 /* file->private_data shall be visible on all CPUs after this */ 1578 smp_mb(); 1579 fuse_send_init(get_fuse_mount_super(sb)); 1580 return 0; 1581 } 1582 1583 /* 1584 * This is the path where user supplied an already initialized fuse dev. In 1585 * this case never create a new super if the old one is gone. 1586 */ 1587 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc) 1588 { 1589 return -ENOTCONN; 1590 } 1591 1592 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc) 1593 { 1594 1595 return fsc->sget_key == get_fuse_conn_super(sb); 1596 } 1597 1598 static int fuse_get_tree(struct fs_context *fsc) 1599 { 1600 struct fuse_fs_context *ctx = fsc->fs_private; 1601 struct fuse_dev *fud; 1602 struct fuse_conn *fc; 1603 struct fuse_mount *fm; 1604 struct super_block *sb; 1605 int err; 1606 1607 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1608 if (!fc) 1609 return -ENOMEM; 1610 1611 fm = kzalloc(sizeof(*fm), GFP_KERNEL); 1612 if (!fm) { 1613 kfree(fc); 1614 return -ENOMEM; 1615 } 1616 1617 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL); 1618 fc->release = fuse_free_conn; 1619 1620 fsc->s_fs_info = fm; 1621 1622 if (ctx->fd_present) 1623 ctx->file = fget(ctx->fd); 1624 1625 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) { 1626 err = get_tree_bdev(fsc, fuse_fill_super); 1627 goto out; 1628 } 1629 /* 1630 * While block dev mount can be initialized with a dummy device fd 1631 * (found by device name), normal fuse mounts can't 1632 */ 1633 err = -EINVAL; 1634 if (!ctx->file) 1635 goto out; 1636 1637 /* 1638 * Allow creating a fuse mount with an already initialized fuse 1639 * connection 1640 */ 1641 fud = READ_ONCE(ctx->file->private_data); 1642 if (ctx->file->f_op == &fuse_dev_operations && fud) { 1643 fsc->sget_key = fud->fc; 1644 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super); 1645 err = PTR_ERR_OR_ZERO(sb); 1646 if (!IS_ERR(sb)) 1647 fsc->root = dget(sb->s_root); 1648 } else { 1649 err = get_tree_nodev(fsc, fuse_fill_super); 1650 } 1651 out: 1652 if (fsc->s_fs_info) 1653 fuse_mount_destroy(fm); 1654 if (ctx->file) 1655 fput(ctx->file); 1656 return err; 1657 } 1658 1659 static const struct fs_context_operations fuse_context_ops = { 1660 .free = fuse_free_fsc, 1661 .parse_param = fuse_parse_param, 1662 .reconfigure = fuse_reconfigure, 1663 .get_tree = fuse_get_tree, 1664 }; 1665 1666 /* 1667 * Set up the filesystem mount context. 1668 */ 1669 static int fuse_init_fs_context(struct fs_context *fsc) 1670 { 1671 struct fuse_fs_context *ctx; 1672 1673 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); 1674 if (!ctx) 1675 return -ENOMEM; 1676 1677 ctx->max_read = ~0; 1678 ctx->blksize = FUSE_DEFAULT_BLKSIZE; 1679 ctx->legacy_opts_show = true; 1680 1681 #ifdef CONFIG_BLOCK 1682 if (fsc->fs_type == &fuseblk_fs_type) { 1683 ctx->is_bdev = true; 1684 ctx->destroy = true; 1685 } 1686 #endif 1687 1688 fsc->fs_private = ctx; 1689 fsc->ops = &fuse_context_ops; 1690 return 0; 1691 } 1692 1693 bool fuse_mount_remove(struct fuse_mount *fm) 1694 { 1695 struct fuse_conn *fc = fm->fc; 1696 bool last = false; 1697 1698 down_write(&fc->killsb); 1699 list_del_init(&fm->fc_entry); 1700 if (list_empty(&fc->mounts)) 1701 last = true; 1702 up_write(&fc->killsb); 1703 1704 return last; 1705 } 1706 EXPORT_SYMBOL_GPL(fuse_mount_remove); 1707 1708 void fuse_conn_destroy(struct fuse_mount *fm) 1709 { 1710 struct fuse_conn *fc = fm->fc; 1711 1712 if (fc->destroy) 1713 fuse_send_destroy(fm); 1714 1715 fuse_abort_conn(fc); 1716 fuse_wait_aborted(fc); 1717 1718 if (!list_empty(&fc->entry)) { 1719 mutex_lock(&fuse_mutex); 1720 list_del(&fc->entry); 1721 fuse_ctl_remove_conn(fc); 1722 mutex_unlock(&fuse_mutex); 1723 } 1724 } 1725 EXPORT_SYMBOL_GPL(fuse_conn_destroy); 1726 1727 static void fuse_sb_destroy(struct super_block *sb) 1728 { 1729 struct fuse_mount *fm = get_fuse_mount_super(sb); 1730 bool last; 1731 1732 if (sb->s_root) { 1733 last = fuse_mount_remove(fm); 1734 if (last) 1735 fuse_conn_destroy(fm); 1736 } 1737 } 1738 1739 void fuse_mount_destroy(struct fuse_mount *fm) 1740 { 1741 fuse_conn_put(fm->fc); 1742 kfree(fm); 1743 } 1744 EXPORT_SYMBOL(fuse_mount_destroy); 1745 1746 static void fuse_kill_sb_anon(struct super_block *sb) 1747 { 1748 fuse_sb_destroy(sb); 1749 kill_anon_super(sb); 1750 fuse_mount_destroy(get_fuse_mount_super(sb)); 1751 } 1752 1753 static struct file_system_type fuse_fs_type = { 1754 .owner = THIS_MODULE, 1755 .name = "fuse", 1756 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, 1757 .init_fs_context = fuse_init_fs_context, 1758 .parameters = fuse_fs_parameters, 1759 .kill_sb = fuse_kill_sb_anon, 1760 }; 1761 MODULE_ALIAS_FS("fuse"); 1762 1763 #ifdef CONFIG_BLOCK 1764 static void fuse_kill_sb_blk(struct super_block *sb) 1765 { 1766 fuse_sb_destroy(sb); 1767 kill_block_super(sb); 1768 fuse_mount_destroy(get_fuse_mount_super(sb)); 1769 } 1770 1771 static struct file_system_type fuseblk_fs_type = { 1772 .owner = THIS_MODULE, 1773 .name = "fuseblk", 1774 .init_fs_context = fuse_init_fs_context, 1775 .parameters = fuse_fs_parameters, 1776 .kill_sb = fuse_kill_sb_blk, 1777 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1778 }; 1779 MODULE_ALIAS_FS("fuseblk"); 1780 1781 static inline int register_fuseblk(void) 1782 { 1783 return register_filesystem(&fuseblk_fs_type); 1784 } 1785 1786 static inline void unregister_fuseblk(void) 1787 { 1788 unregister_filesystem(&fuseblk_fs_type); 1789 } 1790 #else 1791 static inline int register_fuseblk(void) 1792 { 1793 return 0; 1794 } 1795 1796 static inline void unregister_fuseblk(void) 1797 { 1798 } 1799 #endif 1800 1801 static void fuse_inode_init_once(void *foo) 1802 { 1803 struct inode *inode = foo; 1804 1805 inode_init_once(inode); 1806 } 1807 1808 static int __init fuse_fs_init(void) 1809 { 1810 int err; 1811 1812 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1813 sizeof(struct fuse_inode), 0, 1814 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT, 1815 fuse_inode_init_once); 1816 err = -ENOMEM; 1817 if (!fuse_inode_cachep) 1818 goto out; 1819 1820 err = register_fuseblk(); 1821 if (err) 1822 goto out2; 1823 1824 err = register_filesystem(&fuse_fs_type); 1825 if (err) 1826 goto out3; 1827 1828 return 0; 1829 1830 out3: 1831 unregister_fuseblk(); 1832 out2: 1833 kmem_cache_destroy(fuse_inode_cachep); 1834 out: 1835 return err; 1836 } 1837 1838 static void fuse_fs_cleanup(void) 1839 { 1840 unregister_filesystem(&fuse_fs_type); 1841 unregister_fuseblk(); 1842 1843 /* 1844 * Make sure all delayed rcu free inodes are flushed before we 1845 * destroy cache. 1846 */ 1847 rcu_barrier(); 1848 kmem_cache_destroy(fuse_inode_cachep); 1849 } 1850 1851 static struct kobject *fuse_kobj; 1852 1853 static int fuse_sysfs_init(void) 1854 { 1855 int err; 1856 1857 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1858 if (!fuse_kobj) { 1859 err = -ENOMEM; 1860 goto out_err; 1861 } 1862 1863 err = sysfs_create_mount_point(fuse_kobj, "connections"); 1864 if (err) 1865 goto out_fuse_unregister; 1866 1867 return 0; 1868 1869 out_fuse_unregister: 1870 kobject_put(fuse_kobj); 1871 out_err: 1872 return err; 1873 } 1874 1875 static void fuse_sysfs_cleanup(void) 1876 { 1877 sysfs_remove_mount_point(fuse_kobj, "connections"); 1878 kobject_put(fuse_kobj); 1879 } 1880 1881 static int __init fuse_init(void) 1882 { 1883 int res; 1884 1885 pr_info("init (API version %i.%i)\n", 1886 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1887 1888 INIT_LIST_HEAD(&fuse_conn_list); 1889 res = fuse_fs_init(); 1890 if (res) 1891 goto err; 1892 1893 res = fuse_dev_init(); 1894 if (res) 1895 goto err_fs_cleanup; 1896 1897 res = fuse_sysfs_init(); 1898 if (res) 1899 goto err_dev_cleanup; 1900 1901 res = fuse_ctl_init(); 1902 if (res) 1903 goto err_sysfs_cleanup; 1904 1905 sanitize_global_limit(&max_user_bgreq); 1906 sanitize_global_limit(&max_user_congthresh); 1907 1908 return 0; 1909 1910 err_sysfs_cleanup: 1911 fuse_sysfs_cleanup(); 1912 err_dev_cleanup: 1913 fuse_dev_cleanup(); 1914 err_fs_cleanup: 1915 fuse_fs_cleanup(); 1916 err: 1917 return res; 1918 } 1919 1920 static void __exit fuse_exit(void) 1921 { 1922 pr_debug("exit\n"); 1923 1924 fuse_ctl_cleanup(); 1925 fuse_sysfs_cleanup(); 1926 fuse_fs_cleanup(); 1927 fuse_dev_cleanup(); 1928 } 1929 1930 module_init(fuse_init); 1931 module_exit(fuse_exit); 1932