1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/pagemap.h> 12 #include <linux/slab.h> 13 #include <linux/file.h> 14 #include <linux/seq_file.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/fs_context.h> 19 #include <linux/fs_parser.h> 20 #include <linux/statfs.h> 21 #include <linux/random.h> 22 #include <linux/sched.h> 23 #include <linux/exportfs.h> 24 #include <linux/posix_acl.h> 25 #include <linux/pid_namespace.h> 26 #include <uapi/linux/magic.h> 27 28 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 29 MODULE_DESCRIPTION("Filesystem in Userspace"); 30 MODULE_LICENSE("GPL"); 31 32 static struct kmem_cache *fuse_inode_cachep; 33 struct list_head fuse_conn_list; 34 DEFINE_MUTEX(fuse_mutex); 35 36 static int set_global_limit(const char *val, const struct kernel_param *kp); 37 38 unsigned max_user_bgreq; 39 module_param_call(max_user_bgreq, set_global_limit, param_get_uint, 40 &max_user_bgreq, 0644); 41 __MODULE_PARM_TYPE(max_user_bgreq, "uint"); 42 MODULE_PARM_DESC(max_user_bgreq, 43 "Global limit for the maximum number of backgrounded requests an " 44 "unprivileged user can set"); 45 46 unsigned max_user_congthresh; 47 module_param_call(max_user_congthresh, set_global_limit, param_get_uint, 48 &max_user_congthresh, 0644); 49 __MODULE_PARM_TYPE(max_user_congthresh, "uint"); 50 MODULE_PARM_DESC(max_user_congthresh, 51 "Global limit for the maximum congestion threshold an " 52 "unprivileged user can set"); 53 54 #define FUSE_DEFAULT_BLKSIZE 512 55 56 /** Maximum number of outstanding background requests */ 57 #define FUSE_DEFAULT_MAX_BACKGROUND 12 58 59 /** Congestion starts at 75% of maximum */ 60 #define FUSE_DEFAULT_CONGESTION_THRESHOLD (FUSE_DEFAULT_MAX_BACKGROUND * 3 / 4) 61 62 #ifdef CONFIG_BLOCK 63 static struct file_system_type fuseblk_fs_type; 64 #endif 65 66 struct fuse_forget_link *fuse_alloc_forget(void) 67 { 68 return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL_ACCOUNT); 69 } 70 71 static struct inode *fuse_alloc_inode(struct super_block *sb) 72 { 73 struct fuse_inode *fi; 74 75 fi = alloc_inode_sb(sb, fuse_inode_cachep, GFP_KERNEL); 76 if (!fi) 77 return NULL; 78 79 fi->i_time = 0; 80 fi->inval_mask = 0; 81 fi->nodeid = 0; 82 fi->nlookup = 0; 83 fi->attr_version = 0; 84 fi->orig_ino = 0; 85 fi->state = 0; 86 mutex_init(&fi->mutex); 87 spin_lock_init(&fi->lock); 88 fi->forget = fuse_alloc_forget(); 89 if (!fi->forget) 90 goto out_free; 91 92 if (IS_ENABLED(CONFIG_FUSE_DAX) && !fuse_dax_inode_alloc(sb, fi)) 93 goto out_free_forget; 94 95 return &fi->inode; 96 97 out_free_forget: 98 kfree(fi->forget); 99 out_free: 100 kmem_cache_free(fuse_inode_cachep, fi); 101 return NULL; 102 } 103 104 static void fuse_free_inode(struct inode *inode) 105 { 106 struct fuse_inode *fi = get_fuse_inode(inode); 107 108 mutex_destroy(&fi->mutex); 109 kfree(fi->forget); 110 #ifdef CONFIG_FUSE_DAX 111 kfree(fi->dax); 112 #endif 113 kmem_cache_free(fuse_inode_cachep, fi); 114 } 115 116 static void fuse_evict_inode(struct inode *inode) 117 { 118 struct fuse_inode *fi = get_fuse_inode(inode); 119 120 /* Will write inode on close/munmap and in all other dirtiers */ 121 WARN_ON(inode->i_state & I_DIRTY_INODE); 122 123 truncate_inode_pages_final(&inode->i_data); 124 clear_inode(inode); 125 if (inode->i_sb->s_flags & SB_ACTIVE) { 126 struct fuse_conn *fc = get_fuse_conn(inode); 127 128 if (FUSE_IS_DAX(inode)) 129 fuse_dax_inode_cleanup(inode); 130 if (fi->nlookup) { 131 fuse_queue_forget(fc, fi->forget, fi->nodeid, 132 fi->nlookup); 133 fi->forget = NULL; 134 } 135 } 136 if (S_ISREG(inode->i_mode) && !fuse_is_bad(inode)) { 137 WARN_ON(!list_empty(&fi->write_files)); 138 WARN_ON(!list_empty(&fi->queued_writes)); 139 } 140 } 141 142 static int fuse_reconfigure(struct fs_context *fsc) 143 { 144 struct super_block *sb = fsc->root->d_sb; 145 146 sync_filesystem(sb); 147 if (fsc->sb_flags & SB_MANDLOCK) 148 return -EINVAL; 149 150 return 0; 151 } 152 153 /* 154 * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down 155 * so that it will fit. 156 */ 157 static ino_t fuse_squash_ino(u64 ino64) 158 { 159 ino_t ino = (ino_t) ino64; 160 if (sizeof(ino_t) < sizeof(u64)) 161 ino ^= ino64 >> (sizeof(u64) - sizeof(ino_t)) * 8; 162 return ino; 163 } 164 165 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr, 166 u64 attr_valid, u32 cache_mask) 167 { 168 struct fuse_conn *fc = get_fuse_conn(inode); 169 struct fuse_inode *fi = get_fuse_inode(inode); 170 171 lockdep_assert_held(&fi->lock); 172 173 fi->attr_version = atomic64_inc_return(&fc->attr_version); 174 fi->i_time = attr_valid; 175 WRITE_ONCE(fi->inval_mask, 0); 176 177 inode->i_ino = fuse_squash_ino(attr->ino); 178 inode->i_mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); 179 set_nlink(inode, attr->nlink); 180 inode->i_uid = make_kuid(fc->user_ns, attr->uid); 181 inode->i_gid = make_kgid(fc->user_ns, attr->gid); 182 inode->i_blocks = attr->blocks; 183 184 /* Sanitize nsecs */ 185 attr->atimensec = min_t(u32, attr->atimensec, NSEC_PER_SEC - 1); 186 attr->mtimensec = min_t(u32, attr->mtimensec, NSEC_PER_SEC - 1); 187 attr->ctimensec = min_t(u32, attr->ctimensec, NSEC_PER_SEC - 1); 188 189 inode->i_atime.tv_sec = attr->atime; 190 inode->i_atime.tv_nsec = attr->atimensec; 191 /* mtime from server may be stale due to local buffered write */ 192 if (!(cache_mask & STATX_MTIME)) { 193 inode->i_mtime.tv_sec = attr->mtime; 194 inode->i_mtime.tv_nsec = attr->mtimensec; 195 } 196 if (!(cache_mask & STATX_CTIME)) { 197 inode->i_ctime.tv_sec = attr->ctime; 198 inode->i_ctime.tv_nsec = attr->ctimensec; 199 } 200 201 if (attr->blksize != 0) 202 inode->i_blkbits = ilog2(attr->blksize); 203 else 204 inode->i_blkbits = inode->i_sb->s_blocksize_bits; 205 206 /* 207 * Don't set the sticky bit in i_mode, unless we want the VFS 208 * to check permissions. This prevents failures due to the 209 * check in may_delete(). 210 */ 211 fi->orig_i_mode = inode->i_mode; 212 if (!fc->default_permissions) 213 inode->i_mode &= ~S_ISVTX; 214 215 fi->orig_ino = attr->ino; 216 217 /* 218 * We are refreshing inode data and it is possible that another 219 * client set suid/sgid or security.capability xattr. So clear 220 * S_NOSEC. Ideally, we could have cleared it only if suid/sgid 221 * was set or if security.capability xattr was set. But we don't 222 * know if security.capability has been set or not. So clear it 223 * anyway. Its less efficient but should be safe. 224 */ 225 inode->i_flags &= ~S_NOSEC; 226 } 227 228 u32 fuse_get_cache_mask(struct inode *inode) 229 { 230 struct fuse_conn *fc = get_fuse_conn(inode); 231 232 if (!fc->writeback_cache || !S_ISREG(inode->i_mode)) 233 return 0; 234 235 return STATX_MTIME | STATX_CTIME | STATX_SIZE; 236 } 237 238 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr, 239 u64 attr_valid, u64 attr_version) 240 { 241 struct fuse_conn *fc = get_fuse_conn(inode); 242 struct fuse_inode *fi = get_fuse_inode(inode); 243 u32 cache_mask; 244 loff_t oldsize; 245 struct timespec64 old_mtime; 246 247 spin_lock(&fi->lock); 248 /* 249 * In case of writeback_cache enabled, writes update mtime, ctime and 250 * may update i_size. In these cases trust the cached value in the 251 * inode. 252 */ 253 cache_mask = fuse_get_cache_mask(inode); 254 if (cache_mask & STATX_SIZE) 255 attr->size = i_size_read(inode); 256 257 if (cache_mask & STATX_MTIME) { 258 attr->mtime = inode->i_mtime.tv_sec; 259 attr->mtimensec = inode->i_mtime.tv_nsec; 260 } 261 if (cache_mask & STATX_CTIME) { 262 attr->ctime = inode->i_ctime.tv_sec; 263 attr->ctimensec = inode->i_ctime.tv_nsec; 264 } 265 266 if ((attr_version != 0 && fi->attr_version > attr_version) || 267 test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { 268 spin_unlock(&fi->lock); 269 return; 270 } 271 272 old_mtime = inode->i_mtime; 273 fuse_change_attributes_common(inode, attr, attr_valid, cache_mask); 274 275 oldsize = inode->i_size; 276 /* 277 * In case of writeback_cache enabled, the cached writes beyond EOF 278 * extend local i_size without keeping userspace server in sync. So, 279 * attr->size coming from server can be stale. We cannot trust it. 280 */ 281 if (!(cache_mask & STATX_SIZE)) 282 i_size_write(inode, attr->size); 283 spin_unlock(&fi->lock); 284 285 if (!cache_mask && S_ISREG(inode->i_mode)) { 286 bool inval = false; 287 288 if (oldsize != attr->size) { 289 truncate_pagecache(inode, attr->size); 290 if (!fc->explicit_inval_data) 291 inval = true; 292 } else if (fc->auto_inval_data) { 293 struct timespec64 new_mtime = { 294 .tv_sec = attr->mtime, 295 .tv_nsec = attr->mtimensec, 296 }; 297 298 /* 299 * Auto inval mode also checks and invalidates if mtime 300 * has changed. 301 */ 302 if (!timespec64_equal(&old_mtime, &new_mtime)) 303 inval = true; 304 } 305 306 if (inval) 307 invalidate_inode_pages2(inode->i_mapping); 308 } 309 310 if (IS_ENABLED(CONFIG_FUSE_DAX)) 311 fuse_dax_dontcache(inode, attr->flags); 312 } 313 314 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr, 315 struct fuse_conn *fc) 316 { 317 inode->i_mode = attr->mode & S_IFMT; 318 inode->i_size = attr->size; 319 inode->i_mtime.tv_sec = attr->mtime; 320 inode->i_mtime.tv_nsec = attr->mtimensec; 321 inode->i_ctime.tv_sec = attr->ctime; 322 inode->i_ctime.tv_nsec = attr->ctimensec; 323 if (S_ISREG(inode->i_mode)) { 324 fuse_init_common(inode); 325 fuse_init_file_inode(inode, attr->flags); 326 } else if (S_ISDIR(inode->i_mode)) 327 fuse_init_dir(inode); 328 else if (S_ISLNK(inode->i_mode)) 329 fuse_init_symlink(inode); 330 else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || 331 S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 332 fuse_init_common(inode); 333 init_special_inode(inode, inode->i_mode, 334 new_decode_dev(attr->rdev)); 335 } else 336 BUG(); 337 /* 338 * Ensure that we don't cache acls for daemons without FUSE_POSIX_ACL 339 * so they see the exact same behavior as before. 340 */ 341 if (!fc->posix_acl) 342 inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE; 343 } 344 345 static int fuse_inode_eq(struct inode *inode, void *_nodeidp) 346 { 347 u64 nodeid = *(u64 *) _nodeidp; 348 if (get_node_id(inode) == nodeid) 349 return 1; 350 else 351 return 0; 352 } 353 354 static int fuse_inode_set(struct inode *inode, void *_nodeidp) 355 { 356 u64 nodeid = *(u64 *) _nodeidp; 357 get_fuse_inode(inode)->nodeid = nodeid; 358 return 0; 359 } 360 361 struct inode *fuse_iget(struct super_block *sb, u64 nodeid, 362 int generation, struct fuse_attr *attr, 363 u64 attr_valid, u64 attr_version) 364 { 365 struct inode *inode; 366 struct fuse_inode *fi; 367 struct fuse_conn *fc = get_fuse_conn_super(sb); 368 369 /* 370 * Auto mount points get their node id from the submount root, which is 371 * not a unique identifier within this filesystem. 372 * 373 * To avoid conflicts, do not place submount points into the inode hash 374 * table. 375 */ 376 if (fc->auto_submounts && (attr->flags & FUSE_ATTR_SUBMOUNT) && 377 S_ISDIR(attr->mode)) { 378 inode = new_inode(sb); 379 if (!inode) 380 return NULL; 381 382 fuse_init_inode(inode, attr, fc); 383 get_fuse_inode(inode)->nodeid = nodeid; 384 inode->i_flags |= S_AUTOMOUNT; 385 goto done; 386 } 387 388 retry: 389 inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid); 390 if (!inode) 391 return NULL; 392 393 if ((inode->i_state & I_NEW)) { 394 inode->i_flags |= S_NOATIME; 395 if (!fc->writeback_cache || !S_ISREG(attr->mode)) 396 inode->i_flags |= S_NOCMTIME; 397 inode->i_generation = generation; 398 fuse_init_inode(inode, attr, fc); 399 unlock_new_inode(inode); 400 } else if (fuse_stale_inode(inode, generation, attr)) { 401 /* nodeid was reused, any I/O on the old inode should fail */ 402 fuse_make_bad(inode); 403 iput(inode); 404 goto retry; 405 } 406 done: 407 fi = get_fuse_inode(inode); 408 spin_lock(&fi->lock); 409 fi->nlookup++; 410 spin_unlock(&fi->lock); 411 fuse_change_attributes(inode, attr, attr_valid, attr_version); 412 413 return inode; 414 } 415 416 struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid, 417 struct fuse_mount **fm) 418 { 419 struct fuse_mount *fm_iter; 420 struct inode *inode; 421 422 WARN_ON(!rwsem_is_locked(&fc->killsb)); 423 list_for_each_entry(fm_iter, &fc->mounts, fc_entry) { 424 if (!fm_iter->sb) 425 continue; 426 427 inode = ilookup5(fm_iter->sb, nodeid, fuse_inode_eq, &nodeid); 428 if (inode) { 429 if (fm) 430 *fm = fm_iter; 431 return inode; 432 } 433 } 434 435 return NULL; 436 } 437 438 int fuse_reverse_inval_inode(struct fuse_conn *fc, u64 nodeid, 439 loff_t offset, loff_t len) 440 { 441 struct fuse_inode *fi; 442 struct inode *inode; 443 pgoff_t pg_start; 444 pgoff_t pg_end; 445 446 inode = fuse_ilookup(fc, nodeid, NULL); 447 if (!inode) 448 return -ENOENT; 449 450 fi = get_fuse_inode(inode); 451 spin_lock(&fi->lock); 452 fi->attr_version = atomic64_inc_return(&fc->attr_version); 453 spin_unlock(&fi->lock); 454 455 fuse_invalidate_attr(inode); 456 forget_all_cached_acls(inode); 457 if (offset >= 0) { 458 pg_start = offset >> PAGE_SHIFT; 459 if (len <= 0) 460 pg_end = -1; 461 else 462 pg_end = (offset + len - 1) >> PAGE_SHIFT; 463 invalidate_inode_pages2_range(inode->i_mapping, 464 pg_start, pg_end); 465 } 466 iput(inode); 467 return 0; 468 } 469 470 bool fuse_lock_inode(struct inode *inode) 471 { 472 bool locked = false; 473 474 if (!get_fuse_conn(inode)->parallel_dirops) { 475 mutex_lock(&get_fuse_inode(inode)->mutex); 476 locked = true; 477 } 478 479 return locked; 480 } 481 482 void fuse_unlock_inode(struct inode *inode, bool locked) 483 { 484 if (locked) 485 mutex_unlock(&get_fuse_inode(inode)->mutex); 486 } 487 488 static void fuse_umount_begin(struct super_block *sb) 489 { 490 struct fuse_conn *fc = get_fuse_conn_super(sb); 491 492 if (fc->no_force_umount) 493 return; 494 495 fuse_abort_conn(fc); 496 497 // Only retire block-device-based superblocks. 498 if (sb->s_bdev != NULL) 499 retire_super(sb); 500 } 501 502 static void fuse_send_destroy(struct fuse_mount *fm) 503 { 504 if (fm->fc->conn_init) { 505 FUSE_ARGS(args); 506 507 args.opcode = FUSE_DESTROY; 508 args.force = true; 509 args.nocreds = true; 510 fuse_simple_request(fm, &args); 511 } 512 } 513 514 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr) 515 { 516 stbuf->f_type = FUSE_SUPER_MAGIC; 517 stbuf->f_bsize = attr->bsize; 518 stbuf->f_frsize = attr->frsize; 519 stbuf->f_blocks = attr->blocks; 520 stbuf->f_bfree = attr->bfree; 521 stbuf->f_bavail = attr->bavail; 522 stbuf->f_files = attr->files; 523 stbuf->f_ffree = attr->ffree; 524 stbuf->f_namelen = attr->namelen; 525 /* fsid is left zero */ 526 } 527 528 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf) 529 { 530 struct super_block *sb = dentry->d_sb; 531 struct fuse_mount *fm = get_fuse_mount_super(sb); 532 FUSE_ARGS(args); 533 struct fuse_statfs_out outarg; 534 int err; 535 536 if (!fuse_allow_current_process(fm->fc)) { 537 buf->f_type = FUSE_SUPER_MAGIC; 538 return 0; 539 } 540 541 memset(&outarg, 0, sizeof(outarg)); 542 args.in_numargs = 0; 543 args.opcode = FUSE_STATFS; 544 args.nodeid = get_node_id(d_inode(dentry)); 545 args.out_numargs = 1; 546 args.out_args[0].size = sizeof(outarg); 547 args.out_args[0].value = &outarg; 548 err = fuse_simple_request(fm, &args); 549 if (!err) 550 convert_fuse_statfs(buf, &outarg.st); 551 return err; 552 } 553 554 static struct fuse_sync_bucket *fuse_sync_bucket_alloc(void) 555 { 556 struct fuse_sync_bucket *bucket; 557 558 bucket = kzalloc(sizeof(*bucket), GFP_KERNEL | __GFP_NOFAIL); 559 if (bucket) { 560 init_waitqueue_head(&bucket->waitq); 561 /* Initial active count */ 562 atomic_set(&bucket->count, 1); 563 } 564 return bucket; 565 } 566 567 static void fuse_sync_fs_writes(struct fuse_conn *fc) 568 { 569 struct fuse_sync_bucket *bucket, *new_bucket; 570 int count; 571 572 new_bucket = fuse_sync_bucket_alloc(); 573 spin_lock(&fc->lock); 574 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 575 count = atomic_read(&bucket->count); 576 WARN_ON(count < 1); 577 /* No outstanding writes? */ 578 if (count == 1) { 579 spin_unlock(&fc->lock); 580 kfree(new_bucket); 581 return; 582 } 583 584 /* 585 * Completion of new bucket depends on completion of this bucket, so add 586 * one more count. 587 */ 588 atomic_inc(&new_bucket->count); 589 rcu_assign_pointer(fc->curr_bucket, new_bucket); 590 spin_unlock(&fc->lock); 591 /* 592 * Drop initial active count. At this point if all writes in this and 593 * ancestor buckets complete, the count will go to zero and this task 594 * will be woken up. 595 */ 596 atomic_dec(&bucket->count); 597 598 wait_event(bucket->waitq, atomic_read(&bucket->count) == 0); 599 600 /* Drop temp count on descendant bucket */ 601 fuse_sync_bucket_dec(new_bucket); 602 kfree_rcu(bucket, rcu); 603 } 604 605 static int fuse_sync_fs(struct super_block *sb, int wait) 606 { 607 struct fuse_mount *fm = get_fuse_mount_super(sb); 608 struct fuse_conn *fc = fm->fc; 609 struct fuse_syncfs_in inarg; 610 FUSE_ARGS(args); 611 int err; 612 613 /* 614 * Userspace cannot handle the wait == 0 case. Avoid a 615 * gratuitous roundtrip. 616 */ 617 if (!wait) 618 return 0; 619 620 /* The filesystem is being unmounted. Nothing to do. */ 621 if (!sb->s_root) 622 return 0; 623 624 if (!fc->sync_fs) 625 return 0; 626 627 fuse_sync_fs_writes(fc); 628 629 memset(&inarg, 0, sizeof(inarg)); 630 args.in_numargs = 1; 631 args.in_args[0].size = sizeof(inarg); 632 args.in_args[0].value = &inarg; 633 args.opcode = FUSE_SYNCFS; 634 args.nodeid = get_node_id(sb->s_root->d_inode); 635 args.out_numargs = 0; 636 637 err = fuse_simple_request(fm, &args); 638 if (err == -ENOSYS) { 639 fc->sync_fs = 0; 640 err = 0; 641 } 642 643 return err; 644 } 645 646 enum { 647 OPT_SOURCE, 648 OPT_SUBTYPE, 649 OPT_FD, 650 OPT_ROOTMODE, 651 OPT_USER_ID, 652 OPT_GROUP_ID, 653 OPT_DEFAULT_PERMISSIONS, 654 OPT_ALLOW_OTHER, 655 OPT_MAX_READ, 656 OPT_BLKSIZE, 657 OPT_ERR 658 }; 659 660 static const struct fs_parameter_spec fuse_fs_parameters[] = { 661 fsparam_string ("source", OPT_SOURCE), 662 fsparam_u32 ("fd", OPT_FD), 663 fsparam_u32oct ("rootmode", OPT_ROOTMODE), 664 fsparam_u32 ("user_id", OPT_USER_ID), 665 fsparam_u32 ("group_id", OPT_GROUP_ID), 666 fsparam_flag ("default_permissions", OPT_DEFAULT_PERMISSIONS), 667 fsparam_flag ("allow_other", OPT_ALLOW_OTHER), 668 fsparam_u32 ("max_read", OPT_MAX_READ), 669 fsparam_u32 ("blksize", OPT_BLKSIZE), 670 fsparam_string ("subtype", OPT_SUBTYPE), 671 {} 672 }; 673 674 static int fuse_parse_param(struct fs_context *fsc, struct fs_parameter *param) 675 { 676 struct fs_parse_result result; 677 struct fuse_fs_context *ctx = fsc->fs_private; 678 int opt; 679 680 if (fsc->purpose == FS_CONTEXT_FOR_RECONFIGURE) { 681 /* 682 * Ignore options coming from mount(MS_REMOUNT) for backward 683 * compatibility. 684 */ 685 if (fsc->oldapi) 686 return 0; 687 688 return invalfc(fsc, "No changes allowed in reconfigure"); 689 } 690 691 opt = fs_parse(fsc, fuse_fs_parameters, param, &result); 692 if (opt < 0) 693 return opt; 694 695 switch (opt) { 696 case OPT_SOURCE: 697 if (fsc->source) 698 return invalfc(fsc, "Multiple sources specified"); 699 fsc->source = param->string; 700 param->string = NULL; 701 break; 702 703 case OPT_SUBTYPE: 704 if (ctx->subtype) 705 return invalfc(fsc, "Multiple subtypes specified"); 706 ctx->subtype = param->string; 707 param->string = NULL; 708 return 0; 709 710 case OPT_FD: 711 ctx->fd = result.uint_32; 712 ctx->fd_present = true; 713 break; 714 715 case OPT_ROOTMODE: 716 if (!fuse_valid_type(result.uint_32)) 717 return invalfc(fsc, "Invalid rootmode"); 718 ctx->rootmode = result.uint_32; 719 ctx->rootmode_present = true; 720 break; 721 722 case OPT_USER_ID: 723 ctx->user_id = make_kuid(fsc->user_ns, result.uint_32); 724 if (!uid_valid(ctx->user_id)) 725 return invalfc(fsc, "Invalid user_id"); 726 ctx->user_id_present = true; 727 break; 728 729 case OPT_GROUP_ID: 730 ctx->group_id = make_kgid(fsc->user_ns, result.uint_32); 731 if (!gid_valid(ctx->group_id)) 732 return invalfc(fsc, "Invalid group_id"); 733 ctx->group_id_present = true; 734 break; 735 736 case OPT_DEFAULT_PERMISSIONS: 737 ctx->default_permissions = true; 738 break; 739 740 case OPT_ALLOW_OTHER: 741 ctx->allow_other = true; 742 break; 743 744 case OPT_MAX_READ: 745 ctx->max_read = result.uint_32; 746 break; 747 748 case OPT_BLKSIZE: 749 if (!ctx->is_bdev) 750 return invalfc(fsc, "blksize only supported for fuseblk"); 751 ctx->blksize = result.uint_32; 752 break; 753 754 default: 755 return -EINVAL; 756 } 757 758 return 0; 759 } 760 761 static void fuse_free_fsc(struct fs_context *fsc) 762 { 763 struct fuse_fs_context *ctx = fsc->fs_private; 764 765 if (ctx) { 766 kfree(ctx->subtype); 767 kfree(ctx); 768 } 769 } 770 771 static int fuse_show_options(struct seq_file *m, struct dentry *root) 772 { 773 struct super_block *sb = root->d_sb; 774 struct fuse_conn *fc = get_fuse_conn_super(sb); 775 776 if (fc->legacy_opts_show) { 777 seq_printf(m, ",user_id=%u", 778 from_kuid_munged(fc->user_ns, fc->user_id)); 779 seq_printf(m, ",group_id=%u", 780 from_kgid_munged(fc->user_ns, fc->group_id)); 781 if (fc->default_permissions) 782 seq_puts(m, ",default_permissions"); 783 if (fc->allow_other) 784 seq_puts(m, ",allow_other"); 785 if (fc->max_read != ~0) 786 seq_printf(m, ",max_read=%u", fc->max_read); 787 if (sb->s_bdev && sb->s_blocksize != FUSE_DEFAULT_BLKSIZE) 788 seq_printf(m, ",blksize=%lu", sb->s_blocksize); 789 } 790 #ifdef CONFIG_FUSE_DAX 791 if (fc->dax_mode == FUSE_DAX_ALWAYS) 792 seq_puts(m, ",dax=always"); 793 else if (fc->dax_mode == FUSE_DAX_NEVER) 794 seq_puts(m, ",dax=never"); 795 else if (fc->dax_mode == FUSE_DAX_INODE_USER) 796 seq_puts(m, ",dax=inode"); 797 #endif 798 799 return 0; 800 } 801 802 static void fuse_iqueue_init(struct fuse_iqueue *fiq, 803 const struct fuse_iqueue_ops *ops, 804 void *priv) 805 { 806 memset(fiq, 0, sizeof(struct fuse_iqueue)); 807 spin_lock_init(&fiq->lock); 808 init_waitqueue_head(&fiq->waitq); 809 INIT_LIST_HEAD(&fiq->pending); 810 INIT_LIST_HEAD(&fiq->interrupts); 811 fiq->forget_list_tail = &fiq->forget_list_head; 812 fiq->connected = 1; 813 fiq->ops = ops; 814 fiq->priv = priv; 815 } 816 817 static void fuse_pqueue_init(struct fuse_pqueue *fpq) 818 { 819 unsigned int i; 820 821 spin_lock_init(&fpq->lock); 822 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 823 INIT_LIST_HEAD(&fpq->processing[i]); 824 INIT_LIST_HEAD(&fpq->io); 825 fpq->connected = 1; 826 } 827 828 void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm, 829 struct user_namespace *user_ns, 830 const struct fuse_iqueue_ops *fiq_ops, void *fiq_priv) 831 { 832 memset(fc, 0, sizeof(*fc)); 833 spin_lock_init(&fc->lock); 834 spin_lock_init(&fc->bg_lock); 835 init_rwsem(&fc->killsb); 836 refcount_set(&fc->count, 1); 837 atomic_set(&fc->dev_count, 1); 838 init_waitqueue_head(&fc->blocked_waitq); 839 fuse_iqueue_init(&fc->iq, fiq_ops, fiq_priv); 840 INIT_LIST_HEAD(&fc->bg_queue); 841 INIT_LIST_HEAD(&fc->entry); 842 INIT_LIST_HEAD(&fc->devices); 843 atomic_set(&fc->num_waiting, 0); 844 fc->max_background = FUSE_DEFAULT_MAX_BACKGROUND; 845 fc->congestion_threshold = FUSE_DEFAULT_CONGESTION_THRESHOLD; 846 atomic64_set(&fc->khctr, 0); 847 fc->polled_files = RB_ROOT; 848 fc->blocked = 0; 849 fc->initialized = 0; 850 fc->connected = 1; 851 atomic64_set(&fc->attr_version, 1); 852 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); 853 fc->pid_ns = get_pid_ns(task_active_pid_ns(current)); 854 fc->user_ns = get_user_ns(user_ns); 855 fc->max_pages = FUSE_DEFAULT_MAX_PAGES_PER_REQ; 856 fc->max_pages_limit = FUSE_MAX_MAX_PAGES; 857 858 INIT_LIST_HEAD(&fc->mounts); 859 list_add(&fm->fc_entry, &fc->mounts); 860 fm->fc = fc; 861 } 862 EXPORT_SYMBOL_GPL(fuse_conn_init); 863 864 void fuse_conn_put(struct fuse_conn *fc) 865 { 866 if (refcount_dec_and_test(&fc->count)) { 867 struct fuse_iqueue *fiq = &fc->iq; 868 struct fuse_sync_bucket *bucket; 869 870 if (IS_ENABLED(CONFIG_FUSE_DAX)) 871 fuse_dax_conn_free(fc); 872 if (fiq->ops->release) 873 fiq->ops->release(fiq); 874 put_pid_ns(fc->pid_ns); 875 put_user_ns(fc->user_ns); 876 bucket = rcu_dereference_protected(fc->curr_bucket, 1); 877 if (bucket) { 878 WARN_ON(atomic_read(&bucket->count) != 1); 879 kfree(bucket); 880 } 881 fc->release(fc); 882 } 883 } 884 EXPORT_SYMBOL_GPL(fuse_conn_put); 885 886 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc) 887 { 888 refcount_inc(&fc->count); 889 return fc; 890 } 891 EXPORT_SYMBOL_GPL(fuse_conn_get); 892 893 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode) 894 { 895 struct fuse_attr attr; 896 memset(&attr, 0, sizeof(attr)); 897 898 attr.mode = mode; 899 attr.ino = FUSE_ROOT_ID; 900 attr.nlink = 1; 901 return fuse_iget(sb, 1, 0, &attr, 0, 0); 902 } 903 904 struct fuse_inode_handle { 905 u64 nodeid; 906 u32 generation; 907 }; 908 909 static struct dentry *fuse_get_dentry(struct super_block *sb, 910 struct fuse_inode_handle *handle) 911 { 912 struct fuse_conn *fc = get_fuse_conn_super(sb); 913 struct inode *inode; 914 struct dentry *entry; 915 int err = -ESTALE; 916 917 if (handle->nodeid == 0) 918 goto out_err; 919 920 inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid); 921 if (!inode) { 922 struct fuse_entry_out outarg; 923 const struct qstr name = QSTR_INIT(".", 1); 924 925 if (!fc->export_support) 926 goto out_err; 927 928 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg, 929 &inode); 930 if (err && err != -ENOENT) 931 goto out_err; 932 if (err || !inode) { 933 err = -ESTALE; 934 goto out_err; 935 } 936 err = -EIO; 937 if (get_node_id(inode) != handle->nodeid) 938 goto out_iput; 939 } 940 err = -ESTALE; 941 if (inode->i_generation != handle->generation) 942 goto out_iput; 943 944 entry = d_obtain_alias(inode); 945 if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) 946 fuse_invalidate_entry_cache(entry); 947 948 return entry; 949 950 out_iput: 951 iput(inode); 952 out_err: 953 return ERR_PTR(err); 954 } 955 956 static int fuse_encode_fh(struct inode *inode, u32 *fh, int *max_len, 957 struct inode *parent) 958 { 959 int len = parent ? 6 : 3; 960 u64 nodeid; 961 u32 generation; 962 963 if (*max_len < len) { 964 *max_len = len; 965 return FILEID_INVALID; 966 } 967 968 nodeid = get_fuse_inode(inode)->nodeid; 969 generation = inode->i_generation; 970 971 fh[0] = (u32)(nodeid >> 32); 972 fh[1] = (u32)(nodeid & 0xffffffff); 973 fh[2] = generation; 974 975 if (parent) { 976 nodeid = get_fuse_inode(parent)->nodeid; 977 generation = parent->i_generation; 978 979 fh[3] = (u32)(nodeid >> 32); 980 fh[4] = (u32)(nodeid & 0xffffffff); 981 fh[5] = generation; 982 } 983 984 *max_len = len; 985 return parent ? 0x82 : 0x81; 986 } 987 988 static struct dentry *fuse_fh_to_dentry(struct super_block *sb, 989 struct fid *fid, int fh_len, int fh_type) 990 { 991 struct fuse_inode_handle handle; 992 993 if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3) 994 return NULL; 995 996 handle.nodeid = (u64) fid->raw[0] << 32; 997 handle.nodeid |= (u64) fid->raw[1]; 998 handle.generation = fid->raw[2]; 999 return fuse_get_dentry(sb, &handle); 1000 } 1001 1002 static struct dentry *fuse_fh_to_parent(struct super_block *sb, 1003 struct fid *fid, int fh_len, int fh_type) 1004 { 1005 struct fuse_inode_handle parent; 1006 1007 if (fh_type != 0x82 || fh_len < 6) 1008 return NULL; 1009 1010 parent.nodeid = (u64) fid->raw[3] << 32; 1011 parent.nodeid |= (u64) fid->raw[4]; 1012 parent.generation = fid->raw[5]; 1013 return fuse_get_dentry(sb, &parent); 1014 } 1015 1016 static struct dentry *fuse_get_parent(struct dentry *child) 1017 { 1018 struct inode *child_inode = d_inode(child); 1019 struct fuse_conn *fc = get_fuse_conn(child_inode); 1020 struct inode *inode; 1021 struct dentry *parent; 1022 struct fuse_entry_out outarg; 1023 int err; 1024 1025 if (!fc->export_support) 1026 return ERR_PTR(-ESTALE); 1027 1028 err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode), 1029 &dotdot_name, &outarg, &inode); 1030 if (err) { 1031 if (err == -ENOENT) 1032 return ERR_PTR(-ESTALE); 1033 return ERR_PTR(err); 1034 } 1035 1036 parent = d_obtain_alias(inode); 1037 if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) 1038 fuse_invalidate_entry_cache(parent); 1039 1040 return parent; 1041 } 1042 1043 static const struct export_operations fuse_export_operations = { 1044 .fh_to_dentry = fuse_fh_to_dentry, 1045 .fh_to_parent = fuse_fh_to_parent, 1046 .encode_fh = fuse_encode_fh, 1047 .get_parent = fuse_get_parent, 1048 }; 1049 1050 static const struct super_operations fuse_super_operations = { 1051 .alloc_inode = fuse_alloc_inode, 1052 .free_inode = fuse_free_inode, 1053 .evict_inode = fuse_evict_inode, 1054 .write_inode = fuse_write_inode, 1055 .drop_inode = generic_delete_inode, 1056 .umount_begin = fuse_umount_begin, 1057 .statfs = fuse_statfs, 1058 .sync_fs = fuse_sync_fs, 1059 .show_options = fuse_show_options, 1060 }; 1061 1062 static void sanitize_global_limit(unsigned *limit) 1063 { 1064 /* 1065 * The default maximum number of async requests is calculated to consume 1066 * 1/2^13 of the total memory, assuming 392 bytes per request. 1067 */ 1068 if (*limit == 0) 1069 *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) / 392; 1070 1071 if (*limit >= 1 << 16) 1072 *limit = (1 << 16) - 1; 1073 } 1074 1075 static int set_global_limit(const char *val, const struct kernel_param *kp) 1076 { 1077 int rv; 1078 1079 rv = param_set_uint(val, kp); 1080 if (rv) 1081 return rv; 1082 1083 sanitize_global_limit((unsigned *)kp->arg); 1084 1085 return 0; 1086 } 1087 1088 static void process_init_limits(struct fuse_conn *fc, struct fuse_init_out *arg) 1089 { 1090 int cap_sys_admin = capable(CAP_SYS_ADMIN); 1091 1092 if (arg->minor < 13) 1093 return; 1094 1095 sanitize_global_limit(&max_user_bgreq); 1096 sanitize_global_limit(&max_user_congthresh); 1097 1098 spin_lock(&fc->bg_lock); 1099 if (arg->max_background) { 1100 fc->max_background = arg->max_background; 1101 1102 if (!cap_sys_admin && fc->max_background > max_user_bgreq) 1103 fc->max_background = max_user_bgreq; 1104 } 1105 if (arg->congestion_threshold) { 1106 fc->congestion_threshold = arg->congestion_threshold; 1107 1108 if (!cap_sys_admin && 1109 fc->congestion_threshold > max_user_congthresh) 1110 fc->congestion_threshold = max_user_congthresh; 1111 } 1112 spin_unlock(&fc->bg_lock); 1113 } 1114 1115 struct fuse_init_args { 1116 struct fuse_args args; 1117 struct fuse_init_in in; 1118 struct fuse_init_out out; 1119 }; 1120 1121 static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, 1122 int error) 1123 { 1124 struct fuse_conn *fc = fm->fc; 1125 struct fuse_init_args *ia = container_of(args, typeof(*ia), args); 1126 struct fuse_init_out *arg = &ia->out; 1127 bool ok = true; 1128 1129 if (error || arg->major != FUSE_KERNEL_VERSION) 1130 ok = false; 1131 else { 1132 unsigned long ra_pages; 1133 1134 process_init_limits(fc, arg); 1135 1136 if (arg->minor >= 6) { 1137 u64 flags = arg->flags | (u64) arg->flags2 << 32; 1138 1139 ra_pages = arg->max_readahead / PAGE_SIZE; 1140 if (flags & FUSE_ASYNC_READ) 1141 fc->async_read = 1; 1142 if (!(flags & FUSE_POSIX_LOCKS)) 1143 fc->no_lock = 1; 1144 if (arg->minor >= 17) { 1145 if (!(flags & FUSE_FLOCK_LOCKS)) 1146 fc->no_flock = 1; 1147 } else { 1148 if (!(flags & FUSE_POSIX_LOCKS)) 1149 fc->no_flock = 1; 1150 } 1151 if (flags & FUSE_ATOMIC_O_TRUNC) 1152 fc->atomic_o_trunc = 1; 1153 if (arg->minor >= 9) { 1154 /* LOOKUP has dependency on proto version */ 1155 if (flags & FUSE_EXPORT_SUPPORT) 1156 fc->export_support = 1; 1157 } 1158 if (flags & FUSE_BIG_WRITES) 1159 fc->big_writes = 1; 1160 if (flags & FUSE_DONT_MASK) 1161 fc->dont_mask = 1; 1162 if (flags & FUSE_AUTO_INVAL_DATA) 1163 fc->auto_inval_data = 1; 1164 else if (flags & FUSE_EXPLICIT_INVAL_DATA) 1165 fc->explicit_inval_data = 1; 1166 if (flags & FUSE_DO_READDIRPLUS) { 1167 fc->do_readdirplus = 1; 1168 if (flags & FUSE_READDIRPLUS_AUTO) 1169 fc->readdirplus_auto = 1; 1170 } 1171 if (flags & FUSE_ASYNC_DIO) 1172 fc->async_dio = 1; 1173 if (flags & FUSE_WRITEBACK_CACHE) 1174 fc->writeback_cache = 1; 1175 if (flags & FUSE_PARALLEL_DIROPS) 1176 fc->parallel_dirops = 1; 1177 if (flags & FUSE_HANDLE_KILLPRIV) 1178 fc->handle_killpriv = 1; 1179 if (arg->time_gran && arg->time_gran <= 1000000000) 1180 fm->sb->s_time_gran = arg->time_gran; 1181 if ((flags & FUSE_POSIX_ACL)) { 1182 fc->default_permissions = 1; 1183 fc->posix_acl = 1; 1184 } 1185 if (flags & FUSE_CACHE_SYMLINKS) 1186 fc->cache_symlinks = 1; 1187 if (flags & FUSE_ABORT_ERROR) 1188 fc->abort_err = 1; 1189 if (flags & FUSE_MAX_PAGES) { 1190 fc->max_pages = 1191 min_t(unsigned int, fc->max_pages_limit, 1192 max_t(unsigned int, arg->max_pages, 1)); 1193 } 1194 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1195 if (flags & FUSE_MAP_ALIGNMENT && 1196 !fuse_dax_check_alignment(fc, arg->map_alignment)) { 1197 ok = false; 1198 } 1199 if (flags & FUSE_HAS_INODE_DAX) 1200 fc->inode_dax = 1; 1201 } 1202 if (flags & FUSE_HANDLE_KILLPRIV_V2) { 1203 fc->handle_killpriv_v2 = 1; 1204 fm->sb->s_flags |= SB_NOSEC; 1205 } 1206 if (flags & FUSE_SETXATTR_EXT) 1207 fc->setxattr_ext = 1; 1208 if (flags & FUSE_SECURITY_CTX) 1209 fc->init_security = 1; 1210 if (flags & FUSE_CREATE_SUPP_GROUP) 1211 fc->create_supp_group = 1; 1212 } else { 1213 ra_pages = fc->max_read / PAGE_SIZE; 1214 fc->no_lock = 1; 1215 fc->no_flock = 1; 1216 } 1217 1218 fm->sb->s_bdi->ra_pages = 1219 min(fm->sb->s_bdi->ra_pages, ra_pages); 1220 fc->minor = arg->minor; 1221 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write; 1222 fc->max_write = max_t(unsigned, 4096, fc->max_write); 1223 fc->conn_init = 1; 1224 } 1225 kfree(ia); 1226 1227 if (!ok) { 1228 fc->conn_init = 0; 1229 fc->conn_error = 1; 1230 } 1231 1232 fuse_set_initialized(fc); 1233 wake_up_all(&fc->blocked_waitq); 1234 } 1235 1236 void fuse_send_init(struct fuse_mount *fm) 1237 { 1238 struct fuse_init_args *ia; 1239 u64 flags; 1240 1241 ia = kzalloc(sizeof(*ia), GFP_KERNEL | __GFP_NOFAIL); 1242 1243 ia->in.major = FUSE_KERNEL_VERSION; 1244 ia->in.minor = FUSE_KERNEL_MINOR_VERSION; 1245 ia->in.max_readahead = fm->sb->s_bdi->ra_pages * PAGE_SIZE; 1246 flags = 1247 FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC | 1248 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK | 1249 FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ | 1250 FUSE_FLOCK_LOCKS | FUSE_HAS_IOCTL_DIR | FUSE_AUTO_INVAL_DATA | 1251 FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO | 1252 FUSE_WRITEBACK_CACHE | FUSE_NO_OPEN_SUPPORT | 1253 FUSE_PARALLEL_DIROPS | FUSE_HANDLE_KILLPRIV | FUSE_POSIX_ACL | 1254 FUSE_ABORT_ERROR | FUSE_MAX_PAGES | FUSE_CACHE_SYMLINKS | 1255 FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | 1256 FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT | 1257 FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP; 1258 #ifdef CONFIG_FUSE_DAX 1259 if (fm->fc->dax) 1260 flags |= FUSE_MAP_ALIGNMENT; 1261 if (fuse_is_inode_dax_mode(fm->fc->dax_mode)) 1262 flags |= FUSE_HAS_INODE_DAX; 1263 #endif 1264 if (fm->fc->auto_submounts) 1265 flags |= FUSE_SUBMOUNTS; 1266 1267 ia->in.flags = flags; 1268 ia->in.flags2 = flags >> 32; 1269 1270 ia->args.opcode = FUSE_INIT; 1271 ia->args.in_numargs = 1; 1272 ia->args.in_args[0].size = sizeof(ia->in); 1273 ia->args.in_args[0].value = &ia->in; 1274 ia->args.out_numargs = 1; 1275 /* Variable length argument used for backward compatibility 1276 with interface version < 7.5. Rest of init_out is zeroed 1277 by do_get_request(), so a short reply is not a problem */ 1278 ia->args.out_argvar = true; 1279 ia->args.out_args[0].size = sizeof(ia->out); 1280 ia->args.out_args[0].value = &ia->out; 1281 ia->args.force = true; 1282 ia->args.nocreds = true; 1283 ia->args.end = process_init_reply; 1284 1285 if (fuse_simple_background(fm, &ia->args, GFP_KERNEL) != 0) 1286 process_init_reply(fm, &ia->args, -ENOTCONN); 1287 } 1288 EXPORT_SYMBOL_GPL(fuse_send_init); 1289 1290 void fuse_free_conn(struct fuse_conn *fc) 1291 { 1292 WARN_ON(!list_empty(&fc->devices)); 1293 kfree_rcu(fc, rcu); 1294 } 1295 EXPORT_SYMBOL_GPL(fuse_free_conn); 1296 1297 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb) 1298 { 1299 int err; 1300 char *suffix = ""; 1301 1302 if (sb->s_bdev) { 1303 suffix = "-fuseblk"; 1304 /* 1305 * sb->s_bdi points to blkdev's bdi however we want to redirect 1306 * it to our private bdi... 1307 */ 1308 bdi_put(sb->s_bdi); 1309 sb->s_bdi = &noop_backing_dev_info; 1310 } 1311 err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev), 1312 MINOR(fc->dev), suffix); 1313 if (err) 1314 return err; 1315 1316 /* fuse does it's own writeback accounting */ 1317 sb->s_bdi->capabilities &= ~BDI_CAP_WRITEBACK_ACCT; 1318 sb->s_bdi->capabilities |= BDI_CAP_STRICTLIMIT; 1319 1320 /* 1321 * For a single fuse filesystem use max 1% of dirty + 1322 * writeback threshold. 1323 * 1324 * This gives about 1M of write buffer for memory maps on a 1325 * machine with 1G and 10% dirty_ratio, which should be more 1326 * than enough. 1327 * 1328 * Privileged users can raise it by writing to 1329 * 1330 * /sys/class/bdi/<bdi>/max_ratio 1331 */ 1332 bdi_set_max_ratio(sb->s_bdi, 1); 1333 1334 return 0; 1335 } 1336 1337 struct fuse_dev *fuse_dev_alloc(void) 1338 { 1339 struct fuse_dev *fud; 1340 struct list_head *pq; 1341 1342 fud = kzalloc(sizeof(struct fuse_dev), GFP_KERNEL); 1343 if (!fud) 1344 return NULL; 1345 1346 pq = kcalloc(FUSE_PQ_HASH_SIZE, sizeof(struct list_head), GFP_KERNEL); 1347 if (!pq) { 1348 kfree(fud); 1349 return NULL; 1350 } 1351 1352 fud->pq.processing = pq; 1353 fuse_pqueue_init(&fud->pq); 1354 1355 return fud; 1356 } 1357 EXPORT_SYMBOL_GPL(fuse_dev_alloc); 1358 1359 void fuse_dev_install(struct fuse_dev *fud, struct fuse_conn *fc) 1360 { 1361 fud->fc = fuse_conn_get(fc); 1362 spin_lock(&fc->lock); 1363 list_add_tail(&fud->entry, &fc->devices); 1364 spin_unlock(&fc->lock); 1365 } 1366 EXPORT_SYMBOL_GPL(fuse_dev_install); 1367 1368 struct fuse_dev *fuse_dev_alloc_install(struct fuse_conn *fc) 1369 { 1370 struct fuse_dev *fud; 1371 1372 fud = fuse_dev_alloc(); 1373 if (!fud) 1374 return NULL; 1375 1376 fuse_dev_install(fud, fc); 1377 return fud; 1378 } 1379 EXPORT_SYMBOL_GPL(fuse_dev_alloc_install); 1380 1381 void fuse_dev_free(struct fuse_dev *fud) 1382 { 1383 struct fuse_conn *fc = fud->fc; 1384 1385 if (fc) { 1386 spin_lock(&fc->lock); 1387 list_del(&fud->entry); 1388 spin_unlock(&fc->lock); 1389 1390 fuse_conn_put(fc); 1391 } 1392 kfree(fud->pq.processing); 1393 kfree(fud); 1394 } 1395 EXPORT_SYMBOL_GPL(fuse_dev_free); 1396 1397 static void fuse_fill_attr_from_inode(struct fuse_attr *attr, 1398 const struct fuse_inode *fi) 1399 { 1400 *attr = (struct fuse_attr){ 1401 .ino = fi->inode.i_ino, 1402 .size = fi->inode.i_size, 1403 .blocks = fi->inode.i_blocks, 1404 .atime = fi->inode.i_atime.tv_sec, 1405 .mtime = fi->inode.i_mtime.tv_sec, 1406 .ctime = fi->inode.i_ctime.tv_sec, 1407 .atimensec = fi->inode.i_atime.tv_nsec, 1408 .mtimensec = fi->inode.i_mtime.tv_nsec, 1409 .ctimensec = fi->inode.i_ctime.tv_nsec, 1410 .mode = fi->inode.i_mode, 1411 .nlink = fi->inode.i_nlink, 1412 .uid = fi->inode.i_uid.val, 1413 .gid = fi->inode.i_gid.val, 1414 .rdev = fi->inode.i_rdev, 1415 .blksize = 1u << fi->inode.i_blkbits, 1416 }; 1417 } 1418 1419 static void fuse_sb_defaults(struct super_block *sb) 1420 { 1421 sb->s_magic = FUSE_SUPER_MAGIC; 1422 sb->s_op = &fuse_super_operations; 1423 sb->s_xattr = fuse_xattr_handlers; 1424 sb->s_maxbytes = MAX_LFS_FILESIZE; 1425 sb->s_time_gran = 1; 1426 sb->s_export_op = &fuse_export_operations; 1427 sb->s_iflags |= SB_I_IMA_UNVERIFIABLE_SIGNATURE; 1428 if (sb->s_user_ns != &init_user_ns) 1429 sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER; 1430 sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION); 1431 } 1432 1433 static int fuse_fill_super_submount(struct super_block *sb, 1434 struct fuse_inode *parent_fi) 1435 { 1436 struct fuse_mount *fm = get_fuse_mount_super(sb); 1437 struct super_block *parent_sb = parent_fi->inode.i_sb; 1438 struct fuse_attr root_attr; 1439 struct inode *root; 1440 1441 fuse_sb_defaults(sb); 1442 fm->sb = sb; 1443 1444 WARN_ON(sb->s_bdi != &noop_backing_dev_info); 1445 sb->s_bdi = bdi_get(parent_sb->s_bdi); 1446 1447 sb->s_xattr = parent_sb->s_xattr; 1448 sb->s_time_gran = parent_sb->s_time_gran; 1449 sb->s_blocksize = parent_sb->s_blocksize; 1450 sb->s_blocksize_bits = parent_sb->s_blocksize_bits; 1451 sb->s_subtype = kstrdup(parent_sb->s_subtype, GFP_KERNEL); 1452 if (parent_sb->s_subtype && !sb->s_subtype) 1453 return -ENOMEM; 1454 1455 fuse_fill_attr_from_inode(&root_attr, parent_fi); 1456 root = fuse_iget(sb, parent_fi->nodeid, 0, &root_attr, 0, 0); 1457 /* 1458 * This inode is just a duplicate, so it is not looked up and 1459 * its nlookup should not be incremented. fuse_iget() does 1460 * that, though, so undo it here. 1461 */ 1462 get_fuse_inode(root)->nlookup--; 1463 sb->s_d_op = &fuse_dentry_operations; 1464 sb->s_root = d_make_root(root); 1465 if (!sb->s_root) 1466 return -ENOMEM; 1467 1468 return 0; 1469 } 1470 1471 /* Filesystem context private data holds the FUSE inode of the mount point */ 1472 static int fuse_get_tree_submount(struct fs_context *fsc) 1473 { 1474 struct fuse_mount *fm; 1475 struct fuse_inode *mp_fi = fsc->fs_private; 1476 struct fuse_conn *fc = get_fuse_conn(&mp_fi->inode); 1477 struct super_block *sb; 1478 int err; 1479 1480 fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL); 1481 if (!fm) 1482 return -ENOMEM; 1483 1484 fm->fc = fuse_conn_get(fc); 1485 fsc->s_fs_info = fm; 1486 sb = sget_fc(fsc, NULL, set_anon_super_fc); 1487 if (fsc->s_fs_info) 1488 fuse_mount_destroy(fm); 1489 if (IS_ERR(sb)) 1490 return PTR_ERR(sb); 1491 1492 /* Initialize superblock, making @mp_fi its root */ 1493 err = fuse_fill_super_submount(sb, mp_fi); 1494 if (err) { 1495 deactivate_locked_super(sb); 1496 return err; 1497 } 1498 1499 down_write(&fc->killsb); 1500 list_add_tail(&fm->fc_entry, &fc->mounts); 1501 up_write(&fc->killsb); 1502 1503 sb->s_flags |= SB_ACTIVE; 1504 fsc->root = dget(sb->s_root); 1505 1506 return 0; 1507 } 1508 1509 static const struct fs_context_operations fuse_context_submount_ops = { 1510 .get_tree = fuse_get_tree_submount, 1511 }; 1512 1513 int fuse_init_fs_context_submount(struct fs_context *fsc) 1514 { 1515 fsc->ops = &fuse_context_submount_ops; 1516 return 0; 1517 } 1518 EXPORT_SYMBOL_GPL(fuse_init_fs_context_submount); 1519 1520 int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx) 1521 { 1522 struct fuse_dev *fud = NULL; 1523 struct fuse_mount *fm = get_fuse_mount_super(sb); 1524 struct fuse_conn *fc = fm->fc; 1525 struct inode *root; 1526 struct dentry *root_dentry; 1527 int err; 1528 1529 err = -EINVAL; 1530 if (sb->s_flags & SB_MANDLOCK) 1531 goto err; 1532 1533 rcu_assign_pointer(fc->curr_bucket, fuse_sync_bucket_alloc()); 1534 fuse_sb_defaults(sb); 1535 1536 if (ctx->is_bdev) { 1537 #ifdef CONFIG_BLOCK 1538 err = -EINVAL; 1539 if (!sb_set_blocksize(sb, ctx->blksize)) 1540 goto err; 1541 #endif 1542 } else { 1543 sb->s_blocksize = PAGE_SIZE; 1544 sb->s_blocksize_bits = PAGE_SHIFT; 1545 } 1546 1547 sb->s_subtype = ctx->subtype; 1548 ctx->subtype = NULL; 1549 if (IS_ENABLED(CONFIG_FUSE_DAX)) { 1550 err = fuse_dax_conn_alloc(fc, ctx->dax_mode, ctx->dax_dev); 1551 if (err) 1552 goto err; 1553 } 1554 1555 if (ctx->fudptr) { 1556 err = -ENOMEM; 1557 fud = fuse_dev_alloc_install(fc); 1558 if (!fud) 1559 goto err_free_dax; 1560 } 1561 1562 fc->dev = sb->s_dev; 1563 fm->sb = sb; 1564 err = fuse_bdi_init(fc, sb); 1565 if (err) 1566 goto err_dev_free; 1567 1568 /* Handle umasking inside the fuse code */ 1569 if (sb->s_flags & SB_POSIXACL) 1570 fc->dont_mask = 1; 1571 sb->s_flags |= SB_POSIXACL; 1572 1573 fc->default_permissions = ctx->default_permissions; 1574 fc->allow_other = ctx->allow_other; 1575 fc->user_id = ctx->user_id; 1576 fc->group_id = ctx->group_id; 1577 fc->legacy_opts_show = ctx->legacy_opts_show; 1578 fc->max_read = max_t(unsigned int, 4096, ctx->max_read); 1579 fc->destroy = ctx->destroy; 1580 fc->no_control = ctx->no_control; 1581 fc->no_force_umount = ctx->no_force_umount; 1582 1583 err = -ENOMEM; 1584 root = fuse_get_root_inode(sb, ctx->rootmode); 1585 sb->s_d_op = &fuse_root_dentry_operations; 1586 root_dentry = d_make_root(root); 1587 if (!root_dentry) 1588 goto err_dev_free; 1589 /* Root dentry doesn't have .d_revalidate */ 1590 sb->s_d_op = &fuse_dentry_operations; 1591 1592 mutex_lock(&fuse_mutex); 1593 err = -EINVAL; 1594 if (ctx->fudptr && *ctx->fudptr) 1595 goto err_unlock; 1596 1597 err = fuse_ctl_add_conn(fc); 1598 if (err) 1599 goto err_unlock; 1600 1601 list_add_tail(&fc->entry, &fuse_conn_list); 1602 sb->s_root = root_dentry; 1603 if (ctx->fudptr) 1604 *ctx->fudptr = fud; 1605 mutex_unlock(&fuse_mutex); 1606 return 0; 1607 1608 err_unlock: 1609 mutex_unlock(&fuse_mutex); 1610 dput(root_dentry); 1611 err_dev_free: 1612 if (fud) 1613 fuse_dev_free(fud); 1614 err_free_dax: 1615 if (IS_ENABLED(CONFIG_FUSE_DAX)) 1616 fuse_dax_conn_free(fc); 1617 err: 1618 return err; 1619 } 1620 EXPORT_SYMBOL_GPL(fuse_fill_super_common); 1621 1622 static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) 1623 { 1624 struct fuse_fs_context *ctx = fsc->fs_private; 1625 int err; 1626 1627 if (!ctx->file || !ctx->rootmode_present || 1628 !ctx->user_id_present || !ctx->group_id_present) 1629 return -EINVAL; 1630 1631 /* 1632 * Require mount to happen from the same user namespace which 1633 * opened /dev/fuse to prevent potential attacks. 1634 */ 1635 if ((ctx->file->f_op != &fuse_dev_operations) || 1636 (ctx->file->f_cred->user_ns != sb->s_user_ns)) 1637 return -EINVAL; 1638 ctx->fudptr = &ctx->file->private_data; 1639 1640 err = fuse_fill_super_common(sb, ctx); 1641 if (err) 1642 return err; 1643 /* file->private_data shall be visible on all CPUs after this */ 1644 smp_mb(); 1645 fuse_send_init(get_fuse_mount_super(sb)); 1646 return 0; 1647 } 1648 1649 /* 1650 * This is the path where user supplied an already initialized fuse dev. In 1651 * this case never create a new super if the old one is gone. 1652 */ 1653 static int fuse_set_no_super(struct super_block *sb, struct fs_context *fsc) 1654 { 1655 return -ENOTCONN; 1656 } 1657 1658 static int fuse_test_super(struct super_block *sb, struct fs_context *fsc) 1659 { 1660 1661 return fsc->sget_key == get_fuse_conn_super(sb); 1662 } 1663 1664 static int fuse_get_tree(struct fs_context *fsc) 1665 { 1666 struct fuse_fs_context *ctx = fsc->fs_private; 1667 struct fuse_dev *fud; 1668 struct fuse_conn *fc; 1669 struct fuse_mount *fm; 1670 struct super_block *sb; 1671 int err; 1672 1673 fc = kmalloc(sizeof(*fc), GFP_KERNEL); 1674 if (!fc) 1675 return -ENOMEM; 1676 1677 fm = kzalloc(sizeof(*fm), GFP_KERNEL); 1678 if (!fm) { 1679 kfree(fc); 1680 return -ENOMEM; 1681 } 1682 1683 fuse_conn_init(fc, fm, fsc->user_ns, &fuse_dev_fiq_ops, NULL); 1684 fc->release = fuse_free_conn; 1685 1686 fsc->s_fs_info = fm; 1687 1688 if (ctx->fd_present) 1689 ctx->file = fget(ctx->fd); 1690 1691 if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) { 1692 err = get_tree_bdev(fsc, fuse_fill_super); 1693 goto out; 1694 } 1695 /* 1696 * While block dev mount can be initialized with a dummy device fd 1697 * (found by device name), normal fuse mounts can't 1698 */ 1699 err = -EINVAL; 1700 if (!ctx->file) 1701 goto out; 1702 1703 /* 1704 * Allow creating a fuse mount with an already initialized fuse 1705 * connection 1706 */ 1707 fud = READ_ONCE(ctx->file->private_data); 1708 if (ctx->file->f_op == &fuse_dev_operations && fud) { 1709 fsc->sget_key = fud->fc; 1710 sb = sget_fc(fsc, fuse_test_super, fuse_set_no_super); 1711 err = PTR_ERR_OR_ZERO(sb); 1712 if (!IS_ERR(sb)) 1713 fsc->root = dget(sb->s_root); 1714 } else { 1715 err = get_tree_nodev(fsc, fuse_fill_super); 1716 } 1717 out: 1718 if (fsc->s_fs_info) 1719 fuse_mount_destroy(fm); 1720 if (ctx->file) 1721 fput(ctx->file); 1722 return err; 1723 } 1724 1725 static const struct fs_context_operations fuse_context_ops = { 1726 .free = fuse_free_fsc, 1727 .parse_param = fuse_parse_param, 1728 .reconfigure = fuse_reconfigure, 1729 .get_tree = fuse_get_tree, 1730 }; 1731 1732 /* 1733 * Set up the filesystem mount context. 1734 */ 1735 static int fuse_init_fs_context(struct fs_context *fsc) 1736 { 1737 struct fuse_fs_context *ctx; 1738 1739 ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL); 1740 if (!ctx) 1741 return -ENOMEM; 1742 1743 ctx->max_read = ~0; 1744 ctx->blksize = FUSE_DEFAULT_BLKSIZE; 1745 ctx->legacy_opts_show = true; 1746 1747 #ifdef CONFIG_BLOCK 1748 if (fsc->fs_type == &fuseblk_fs_type) { 1749 ctx->is_bdev = true; 1750 ctx->destroy = true; 1751 } 1752 #endif 1753 1754 fsc->fs_private = ctx; 1755 fsc->ops = &fuse_context_ops; 1756 return 0; 1757 } 1758 1759 bool fuse_mount_remove(struct fuse_mount *fm) 1760 { 1761 struct fuse_conn *fc = fm->fc; 1762 bool last = false; 1763 1764 down_write(&fc->killsb); 1765 list_del_init(&fm->fc_entry); 1766 if (list_empty(&fc->mounts)) 1767 last = true; 1768 up_write(&fc->killsb); 1769 1770 return last; 1771 } 1772 EXPORT_SYMBOL_GPL(fuse_mount_remove); 1773 1774 void fuse_conn_destroy(struct fuse_mount *fm) 1775 { 1776 struct fuse_conn *fc = fm->fc; 1777 1778 if (fc->destroy) 1779 fuse_send_destroy(fm); 1780 1781 fuse_abort_conn(fc); 1782 fuse_wait_aborted(fc); 1783 1784 if (!list_empty(&fc->entry)) { 1785 mutex_lock(&fuse_mutex); 1786 list_del(&fc->entry); 1787 fuse_ctl_remove_conn(fc); 1788 mutex_unlock(&fuse_mutex); 1789 } 1790 } 1791 EXPORT_SYMBOL_GPL(fuse_conn_destroy); 1792 1793 static void fuse_sb_destroy(struct super_block *sb) 1794 { 1795 struct fuse_mount *fm = get_fuse_mount_super(sb); 1796 bool last; 1797 1798 if (sb->s_root) { 1799 last = fuse_mount_remove(fm); 1800 if (last) 1801 fuse_conn_destroy(fm); 1802 } 1803 } 1804 1805 void fuse_mount_destroy(struct fuse_mount *fm) 1806 { 1807 fuse_conn_put(fm->fc); 1808 kfree(fm); 1809 } 1810 EXPORT_SYMBOL(fuse_mount_destroy); 1811 1812 static void fuse_kill_sb_anon(struct super_block *sb) 1813 { 1814 fuse_sb_destroy(sb); 1815 kill_anon_super(sb); 1816 fuse_mount_destroy(get_fuse_mount_super(sb)); 1817 } 1818 1819 static struct file_system_type fuse_fs_type = { 1820 .owner = THIS_MODULE, 1821 .name = "fuse", 1822 .fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT, 1823 .init_fs_context = fuse_init_fs_context, 1824 .parameters = fuse_fs_parameters, 1825 .kill_sb = fuse_kill_sb_anon, 1826 }; 1827 MODULE_ALIAS_FS("fuse"); 1828 1829 #ifdef CONFIG_BLOCK 1830 static void fuse_kill_sb_blk(struct super_block *sb) 1831 { 1832 fuse_sb_destroy(sb); 1833 kill_block_super(sb); 1834 fuse_mount_destroy(get_fuse_mount_super(sb)); 1835 } 1836 1837 static struct file_system_type fuseblk_fs_type = { 1838 .owner = THIS_MODULE, 1839 .name = "fuseblk", 1840 .init_fs_context = fuse_init_fs_context, 1841 .parameters = fuse_fs_parameters, 1842 .kill_sb = fuse_kill_sb_blk, 1843 .fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE, 1844 }; 1845 MODULE_ALIAS_FS("fuseblk"); 1846 1847 static inline int register_fuseblk(void) 1848 { 1849 return register_filesystem(&fuseblk_fs_type); 1850 } 1851 1852 static inline void unregister_fuseblk(void) 1853 { 1854 unregister_filesystem(&fuseblk_fs_type); 1855 } 1856 #else 1857 static inline int register_fuseblk(void) 1858 { 1859 return 0; 1860 } 1861 1862 static inline void unregister_fuseblk(void) 1863 { 1864 } 1865 #endif 1866 1867 static void fuse_inode_init_once(void *foo) 1868 { 1869 struct inode *inode = foo; 1870 1871 inode_init_once(inode); 1872 } 1873 1874 static int __init fuse_fs_init(void) 1875 { 1876 int err; 1877 1878 fuse_inode_cachep = kmem_cache_create("fuse_inode", 1879 sizeof(struct fuse_inode), 0, 1880 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT, 1881 fuse_inode_init_once); 1882 err = -ENOMEM; 1883 if (!fuse_inode_cachep) 1884 goto out; 1885 1886 err = register_fuseblk(); 1887 if (err) 1888 goto out2; 1889 1890 err = register_filesystem(&fuse_fs_type); 1891 if (err) 1892 goto out3; 1893 1894 return 0; 1895 1896 out3: 1897 unregister_fuseblk(); 1898 out2: 1899 kmem_cache_destroy(fuse_inode_cachep); 1900 out: 1901 return err; 1902 } 1903 1904 static void fuse_fs_cleanup(void) 1905 { 1906 unregister_filesystem(&fuse_fs_type); 1907 unregister_fuseblk(); 1908 1909 /* 1910 * Make sure all delayed rcu free inodes are flushed before we 1911 * destroy cache. 1912 */ 1913 rcu_barrier(); 1914 kmem_cache_destroy(fuse_inode_cachep); 1915 } 1916 1917 static struct kobject *fuse_kobj; 1918 1919 static int fuse_sysfs_init(void) 1920 { 1921 int err; 1922 1923 fuse_kobj = kobject_create_and_add("fuse", fs_kobj); 1924 if (!fuse_kobj) { 1925 err = -ENOMEM; 1926 goto out_err; 1927 } 1928 1929 err = sysfs_create_mount_point(fuse_kobj, "connections"); 1930 if (err) 1931 goto out_fuse_unregister; 1932 1933 return 0; 1934 1935 out_fuse_unregister: 1936 kobject_put(fuse_kobj); 1937 out_err: 1938 return err; 1939 } 1940 1941 static void fuse_sysfs_cleanup(void) 1942 { 1943 sysfs_remove_mount_point(fuse_kobj, "connections"); 1944 kobject_put(fuse_kobj); 1945 } 1946 1947 static int __init fuse_init(void) 1948 { 1949 int res; 1950 1951 pr_info("init (API version %i.%i)\n", 1952 FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION); 1953 1954 INIT_LIST_HEAD(&fuse_conn_list); 1955 res = fuse_fs_init(); 1956 if (res) 1957 goto err; 1958 1959 res = fuse_dev_init(); 1960 if (res) 1961 goto err_fs_cleanup; 1962 1963 res = fuse_sysfs_init(); 1964 if (res) 1965 goto err_dev_cleanup; 1966 1967 res = fuse_ctl_init(); 1968 if (res) 1969 goto err_sysfs_cleanup; 1970 1971 sanitize_global_limit(&max_user_bgreq); 1972 sanitize_global_limit(&max_user_congthresh); 1973 1974 return 0; 1975 1976 err_sysfs_cleanup: 1977 fuse_sysfs_cleanup(); 1978 err_dev_cleanup: 1979 fuse_dev_cleanup(); 1980 err_fs_cleanup: 1981 fuse_fs_cleanup(); 1982 err: 1983 return res; 1984 } 1985 1986 static void __exit fuse_exit(void) 1987 { 1988 pr_debug("exit\n"); 1989 1990 fuse_ctl_cleanup(); 1991 fuse_sysfs_cleanup(); 1992 fuse_fs_cleanup(); 1993 fuse_dev_cleanup(); 1994 } 1995 1996 module_init(fuse_init); 1997 module_exit(fuse_exit); 1998