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/init.h> 12 #include <linux/module.h> 13 #include <linux/poll.h> 14 #include <linux/sched/signal.h> 15 #include <linux/uio.h> 16 #include <linux/miscdevice.h> 17 #include <linux/pagemap.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/pipe_fs_i.h> 21 #include <linux/swap.h> 22 #include <linux/splice.h> 23 #include <linux/sched.h> 24 25 MODULE_ALIAS_MISCDEV(FUSE_MINOR); 26 MODULE_ALIAS("devname:fuse"); 27 28 /* Ordinary requests have even IDs, while interrupts IDs are odd */ 29 #define FUSE_INT_REQ_BIT (1ULL << 0) 30 #define FUSE_REQ_ID_STEP (1ULL << 1) 31 32 static struct kmem_cache *fuse_req_cachep; 33 34 static void end_requests(struct list_head *head); 35 36 static struct fuse_dev *fuse_get_dev(struct file *file) 37 { 38 /* 39 * Lockless access is OK, because file->private data is set 40 * once during mount and is valid until the file is released. 41 */ 42 return READ_ONCE(file->private_data); 43 } 44 45 static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req) 46 { 47 INIT_LIST_HEAD(&req->list); 48 INIT_LIST_HEAD(&req->intr_entry); 49 init_waitqueue_head(&req->waitq); 50 refcount_set(&req->count, 1); 51 __set_bit(FR_PENDING, &req->flags); 52 req->fm = fm; 53 } 54 55 static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags) 56 { 57 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags); 58 if (req) 59 fuse_request_init(fm, req); 60 61 return req; 62 } 63 64 static void fuse_request_free(struct fuse_req *req) 65 { 66 kmem_cache_free(fuse_req_cachep, req); 67 } 68 69 static void __fuse_get_request(struct fuse_req *req) 70 { 71 refcount_inc(&req->count); 72 } 73 74 /* Must be called with > 1 refcount */ 75 static void __fuse_put_request(struct fuse_req *req) 76 { 77 refcount_dec(&req->count); 78 } 79 80 void fuse_set_initialized(struct fuse_conn *fc) 81 { 82 /* Make sure stores before this are seen on another CPU */ 83 smp_wmb(); 84 fc->initialized = 1; 85 } 86 87 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 88 { 89 return !fc->initialized || (for_background && fc->blocked); 90 } 91 92 static void fuse_drop_waiting(struct fuse_conn *fc) 93 { 94 /* 95 * lockess check of fc->connected is okay, because atomic_dec_and_test() 96 * provides a memory barrier matched with the one in fuse_wait_aborted() 97 * to ensure no wake-up is missed. 98 */ 99 if (atomic_dec_and_test(&fc->num_waiting) && 100 !READ_ONCE(fc->connected)) { 101 /* wake up aborters */ 102 wake_up_all(&fc->blocked_waitq); 103 } 104 } 105 106 static void fuse_put_request(struct fuse_req *req); 107 108 static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background) 109 { 110 struct fuse_conn *fc = fm->fc; 111 struct fuse_req *req; 112 int err; 113 atomic_inc(&fc->num_waiting); 114 115 if (fuse_block_alloc(fc, for_background)) { 116 err = -EINTR; 117 if (wait_event_killable_exclusive(fc->blocked_waitq, 118 !fuse_block_alloc(fc, for_background))) 119 goto out; 120 } 121 /* Matches smp_wmb() in fuse_set_initialized() */ 122 smp_rmb(); 123 124 err = -ENOTCONN; 125 if (!fc->connected) 126 goto out; 127 128 err = -ECONNREFUSED; 129 if (fc->conn_error) 130 goto out; 131 132 req = fuse_request_alloc(fm, GFP_KERNEL); 133 err = -ENOMEM; 134 if (!req) { 135 if (for_background) 136 wake_up(&fc->blocked_waitq); 137 goto out; 138 } 139 140 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid()); 141 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid()); 142 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 143 144 __set_bit(FR_WAITING, &req->flags); 145 if (for_background) 146 __set_bit(FR_BACKGROUND, &req->flags); 147 148 if (unlikely(req->in.h.uid == ((uid_t)-1) || 149 req->in.h.gid == ((gid_t)-1))) { 150 fuse_put_request(req); 151 return ERR_PTR(-EOVERFLOW); 152 } 153 return req; 154 155 out: 156 fuse_drop_waiting(fc); 157 return ERR_PTR(err); 158 } 159 160 static void fuse_put_request(struct fuse_req *req) 161 { 162 struct fuse_conn *fc = req->fm->fc; 163 164 if (refcount_dec_and_test(&req->count)) { 165 if (test_bit(FR_BACKGROUND, &req->flags)) { 166 /* 167 * We get here in the unlikely case that a background 168 * request was allocated but not sent 169 */ 170 spin_lock(&fc->bg_lock); 171 if (!fc->blocked) 172 wake_up(&fc->blocked_waitq); 173 spin_unlock(&fc->bg_lock); 174 } 175 176 if (test_bit(FR_WAITING, &req->flags)) { 177 __clear_bit(FR_WAITING, &req->flags); 178 fuse_drop_waiting(fc); 179 } 180 181 fuse_request_free(req); 182 } 183 } 184 185 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args) 186 { 187 unsigned nbytes = 0; 188 unsigned i; 189 190 for (i = 0; i < numargs; i++) 191 nbytes += args[i].size; 192 193 return nbytes; 194 } 195 EXPORT_SYMBOL_GPL(fuse_len_args); 196 197 u64 fuse_get_unique(struct fuse_iqueue *fiq) 198 { 199 fiq->reqctr += FUSE_REQ_ID_STEP; 200 return fiq->reqctr; 201 } 202 EXPORT_SYMBOL_GPL(fuse_get_unique); 203 204 static unsigned int fuse_req_hash(u64 unique) 205 { 206 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS); 207 } 208 209 /* 210 * A new request is available, wake fiq->waitq 211 */ 212 static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq) 213 __releases(fiq->lock) 214 { 215 wake_up(&fiq->waitq); 216 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 217 spin_unlock(&fiq->lock); 218 } 219 220 const struct fuse_iqueue_ops fuse_dev_fiq_ops = { 221 .wake_forget_and_unlock = fuse_dev_wake_and_unlock, 222 .wake_interrupt_and_unlock = fuse_dev_wake_and_unlock, 223 .wake_pending_and_unlock = fuse_dev_wake_and_unlock, 224 }; 225 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops); 226 227 static void queue_request_and_unlock(struct fuse_iqueue *fiq, 228 struct fuse_req *req) 229 __releases(fiq->lock) 230 { 231 req->in.h.len = sizeof(struct fuse_in_header) + 232 fuse_len_args(req->args->in_numargs, 233 (struct fuse_arg *) req->args->in_args); 234 list_add_tail(&req->list, &fiq->pending); 235 fiq->ops->wake_pending_and_unlock(fiq); 236 } 237 238 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 239 u64 nodeid, u64 nlookup) 240 { 241 struct fuse_iqueue *fiq = &fc->iq; 242 243 forget->forget_one.nodeid = nodeid; 244 forget->forget_one.nlookup = nlookup; 245 246 spin_lock(&fiq->lock); 247 if (fiq->connected) { 248 fiq->forget_list_tail->next = forget; 249 fiq->forget_list_tail = forget; 250 fiq->ops->wake_forget_and_unlock(fiq); 251 } else { 252 kfree(forget); 253 spin_unlock(&fiq->lock); 254 } 255 } 256 257 static void flush_bg_queue(struct fuse_conn *fc) 258 { 259 struct fuse_iqueue *fiq = &fc->iq; 260 261 while (fc->active_background < fc->max_background && 262 !list_empty(&fc->bg_queue)) { 263 struct fuse_req *req; 264 265 req = list_first_entry(&fc->bg_queue, struct fuse_req, list); 266 list_del(&req->list); 267 fc->active_background++; 268 spin_lock(&fiq->lock); 269 req->in.h.unique = fuse_get_unique(fiq); 270 queue_request_and_unlock(fiq, req); 271 } 272 } 273 274 /* 275 * This function is called when a request is finished. Either a reply 276 * has arrived or it was aborted (and not yet sent) or some error 277 * occurred during communication with userspace, or the device file 278 * was closed. The requester thread is woken up (if still waiting), 279 * the 'end' callback is called if given, else the reference to the 280 * request is released 281 */ 282 void fuse_request_end(struct fuse_req *req) 283 { 284 struct fuse_mount *fm = req->fm; 285 struct fuse_conn *fc = fm->fc; 286 struct fuse_iqueue *fiq = &fc->iq; 287 288 if (test_and_set_bit(FR_FINISHED, &req->flags)) 289 goto put_request; 290 291 /* 292 * test_and_set_bit() implies smp_mb() between bit 293 * changing and below FR_INTERRUPTED check. Pairs with 294 * smp_mb() from queue_interrupt(). 295 */ 296 if (test_bit(FR_INTERRUPTED, &req->flags)) { 297 spin_lock(&fiq->lock); 298 list_del_init(&req->intr_entry); 299 spin_unlock(&fiq->lock); 300 } 301 WARN_ON(test_bit(FR_PENDING, &req->flags)); 302 WARN_ON(test_bit(FR_SENT, &req->flags)); 303 if (test_bit(FR_BACKGROUND, &req->flags)) { 304 spin_lock(&fc->bg_lock); 305 clear_bit(FR_BACKGROUND, &req->flags); 306 if (fc->num_background == fc->max_background) { 307 fc->blocked = 0; 308 wake_up(&fc->blocked_waitq); 309 } else if (!fc->blocked) { 310 /* 311 * Wake up next waiter, if any. It's okay to use 312 * waitqueue_active(), as we've already synced up 313 * fc->blocked with waiters with the wake_up() call 314 * above. 315 */ 316 if (waitqueue_active(&fc->blocked_waitq)) 317 wake_up(&fc->blocked_waitq); 318 } 319 320 fc->num_background--; 321 fc->active_background--; 322 flush_bg_queue(fc); 323 spin_unlock(&fc->bg_lock); 324 } else { 325 /* Wake up waiter sleeping in request_wait_answer() */ 326 wake_up(&req->waitq); 327 } 328 329 if (test_bit(FR_ASYNC, &req->flags)) 330 req->args->end(fm, req->args, req->out.h.error); 331 put_request: 332 fuse_put_request(req); 333 } 334 EXPORT_SYMBOL_GPL(fuse_request_end); 335 336 static int queue_interrupt(struct fuse_req *req) 337 { 338 struct fuse_iqueue *fiq = &req->fm->fc->iq; 339 340 spin_lock(&fiq->lock); 341 /* Check for we've sent request to interrupt this req */ 342 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) { 343 spin_unlock(&fiq->lock); 344 return -EINVAL; 345 } 346 347 if (list_empty(&req->intr_entry)) { 348 list_add_tail(&req->intr_entry, &fiq->interrupts); 349 /* 350 * Pairs with smp_mb() implied by test_and_set_bit() 351 * from fuse_request_end(). 352 */ 353 smp_mb(); 354 if (test_bit(FR_FINISHED, &req->flags)) { 355 list_del_init(&req->intr_entry); 356 spin_unlock(&fiq->lock); 357 return 0; 358 } 359 fiq->ops->wake_interrupt_and_unlock(fiq); 360 } else { 361 spin_unlock(&fiq->lock); 362 } 363 return 0; 364 } 365 366 static void request_wait_answer(struct fuse_req *req) 367 { 368 struct fuse_conn *fc = req->fm->fc; 369 struct fuse_iqueue *fiq = &fc->iq; 370 int err; 371 372 if (!fc->no_interrupt) { 373 /* Any signal may interrupt this */ 374 err = wait_event_interruptible(req->waitq, 375 test_bit(FR_FINISHED, &req->flags)); 376 if (!err) 377 return; 378 379 set_bit(FR_INTERRUPTED, &req->flags); 380 /* matches barrier in fuse_dev_do_read() */ 381 smp_mb__after_atomic(); 382 if (test_bit(FR_SENT, &req->flags)) 383 queue_interrupt(req); 384 } 385 386 if (!test_bit(FR_FORCE, &req->flags)) { 387 /* Only fatal signals may interrupt this */ 388 err = wait_event_killable(req->waitq, 389 test_bit(FR_FINISHED, &req->flags)); 390 if (!err) 391 return; 392 393 spin_lock(&fiq->lock); 394 /* Request is not yet in userspace, bail out */ 395 if (test_bit(FR_PENDING, &req->flags)) { 396 list_del(&req->list); 397 spin_unlock(&fiq->lock); 398 __fuse_put_request(req); 399 req->out.h.error = -EINTR; 400 return; 401 } 402 spin_unlock(&fiq->lock); 403 } 404 405 /* 406 * Either request is already in userspace, or it was forced. 407 * Wait it out. 408 */ 409 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags)); 410 } 411 412 static void __fuse_request_send(struct fuse_req *req) 413 { 414 struct fuse_iqueue *fiq = &req->fm->fc->iq; 415 416 BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); 417 spin_lock(&fiq->lock); 418 if (!fiq->connected) { 419 spin_unlock(&fiq->lock); 420 req->out.h.error = -ENOTCONN; 421 } else { 422 req->in.h.unique = fuse_get_unique(fiq); 423 /* acquire extra reference, since request is still needed 424 after fuse_request_end() */ 425 __fuse_get_request(req); 426 queue_request_and_unlock(fiq, req); 427 428 request_wait_answer(req); 429 /* Pairs with smp_wmb() in fuse_request_end() */ 430 smp_rmb(); 431 } 432 } 433 434 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) 435 { 436 if (fc->minor < 4 && args->opcode == FUSE_STATFS) 437 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE; 438 439 if (fc->minor < 9) { 440 switch (args->opcode) { 441 case FUSE_LOOKUP: 442 case FUSE_CREATE: 443 case FUSE_MKNOD: 444 case FUSE_MKDIR: 445 case FUSE_SYMLINK: 446 case FUSE_LINK: 447 args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; 448 break; 449 case FUSE_GETATTR: 450 case FUSE_SETATTR: 451 args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; 452 break; 453 } 454 } 455 if (fc->minor < 12) { 456 switch (args->opcode) { 457 case FUSE_CREATE: 458 args->in_args[0].size = sizeof(struct fuse_open_in); 459 break; 460 case FUSE_MKNOD: 461 args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; 462 break; 463 } 464 } 465 } 466 467 static void fuse_force_creds(struct fuse_req *req) 468 { 469 struct fuse_conn *fc = req->fm->fc; 470 471 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid()); 472 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid()); 473 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 474 } 475 476 static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args) 477 { 478 req->in.h.opcode = args->opcode; 479 req->in.h.nodeid = args->nodeid; 480 req->args = args; 481 if (args->is_ext) 482 req->in.h.total_extlen = args->in_args[args->ext_idx].size / 8; 483 if (args->end) 484 __set_bit(FR_ASYNC, &req->flags); 485 } 486 487 ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args) 488 { 489 struct fuse_conn *fc = fm->fc; 490 struct fuse_req *req; 491 ssize_t ret; 492 493 if (args->force) { 494 atomic_inc(&fc->num_waiting); 495 req = fuse_request_alloc(fm, GFP_KERNEL | __GFP_NOFAIL); 496 497 if (!args->nocreds) 498 fuse_force_creds(req); 499 500 __set_bit(FR_WAITING, &req->flags); 501 __set_bit(FR_FORCE, &req->flags); 502 } else { 503 WARN_ON(args->nocreds); 504 req = fuse_get_req(fm, false); 505 if (IS_ERR(req)) 506 return PTR_ERR(req); 507 } 508 509 /* Needs to be done after fuse_get_req() so that fc->minor is valid */ 510 fuse_adjust_compat(fc, args); 511 fuse_args_to_req(req, args); 512 513 if (!args->noreply) 514 __set_bit(FR_ISREPLY, &req->flags); 515 __fuse_request_send(req); 516 ret = req->out.h.error; 517 if (!ret && args->out_argvar) { 518 BUG_ON(args->out_numargs == 0); 519 ret = args->out_args[args->out_numargs - 1].size; 520 } 521 fuse_put_request(req); 522 523 return ret; 524 } 525 526 static bool fuse_request_queue_background(struct fuse_req *req) 527 { 528 struct fuse_mount *fm = req->fm; 529 struct fuse_conn *fc = fm->fc; 530 bool queued = false; 531 532 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags)); 533 if (!test_bit(FR_WAITING, &req->flags)) { 534 __set_bit(FR_WAITING, &req->flags); 535 atomic_inc(&fc->num_waiting); 536 } 537 __set_bit(FR_ISREPLY, &req->flags); 538 spin_lock(&fc->bg_lock); 539 if (likely(fc->connected)) { 540 fc->num_background++; 541 if (fc->num_background == fc->max_background) 542 fc->blocked = 1; 543 list_add_tail(&req->list, &fc->bg_queue); 544 flush_bg_queue(fc); 545 queued = true; 546 } 547 spin_unlock(&fc->bg_lock); 548 549 return queued; 550 } 551 552 int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args, 553 gfp_t gfp_flags) 554 { 555 struct fuse_req *req; 556 557 if (args->force) { 558 WARN_ON(!args->nocreds); 559 req = fuse_request_alloc(fm, gfp_flags); 560 if (!req) 561 return -ENOMEM; 562 __set_bit(FR_BACKGROUND, &req->flags); 563 } else { 564 WARN_ON(args->nocreds); 565 req = fuse_get_req(fm, true); 566 if (IS_ERR(req)) 567 return PTR_ERR(req); 568 } 569 570 fuse_args_to_req(req, args); 571 572 if (!fuse_request_queue_background(req)) { 573 fuse_put_request(req); 574 return -ENOTCONN; 575 } 576 577 return 0; 578 } 579 EXPORT_SYMBOL_GPL(fuse_simple_background); 580 581 static int fuse_simple_notify_reply(struct fuse_mount *fm, 582 struct fuse_args *args, u64 unique) 583 { 584 struct fuse_req *req; 585 struct fuse_iqueue *fiq = &fm->fc->iq; 586 int err = 0; 587 588 req = fuse_get_req(fm, false); 589 if (IS_ERR(req)) 590 return PTR_ERR(req); 591 592 __clear_bit(FR_ISREPLY, &req->flags); 593 req->in.h.unique = unique; 594 595 fuse_args_to_req(req, args); 596 597 spin_lock(&fiq->lock); 598 if (fiq->connected) { 599 queue_request_and_unlock(fiq, req); 600 } else { 601 err = -ENODEV; 602 spin_unlock(&fiq->lock); 603 fuse_put_request(req); 604 } 605 606 return err; 607 } 608 609 /* 610 * Lock the request. Up to the next unlock_request() there mustn't be 611 * anything that could cause a page-fault. If the request was already 612 * aborted bail out. 613 */ 614 static int lock_request(struct fuse_req *req) 615 { 616 int err = 0; 617 if (req) { 618 spin_lock(&req->waitq.lock); 619 if (test_bit(FR_ABORTED, &req->flags)) 620 err = -ENOENT; 621 else 622 set_bit(FR_LOCKED, &req->flags); 623 spin_unlock(&req->waitq.lock); 624 } 625 return err; 626 } 627 628 /* 629 * Unlock request. If it was aborted while locked, caller is responsible 630 * for unlocking and ending the request. 631 */ 632 static int unlock_request(struct fuse_req *req) 633 { 634 int err = 0; 635 if (req) { 636 spin_lock(&req->waitq.lock); 637 if (test_bit(FR_ABORTED, &req->flags)) 638 err = -ENOENT; 639 else 640 clear_bit(FR_LOCKED, &req->flags); 641 spin_unlock(&req->waitq.lock); 642 } 643 return err; 644 } 645 646 struct fuse_copy_state { 647 int write; 648 struct fuse_req *req; 649 struct iov_iter *iter; 650 struct pipe_buffer *pipebufs; 651 struct pipe_buffer *currbuf; 652 struct pipe_inode_info *pipe; 653 unsigned long nr_segs; 654 struct page *pg; 655 unsigned len; 656 unsigned offset; 657 unsigned move_pages:1; 658 }; 659 660 static void fuse_copy_init(struct fuse_copy_state *cs, int write, 661 struct iov_iter *iter) 662 { 663 memset(cs, 0, sizeof(*cs)); 664 cs->write = write; 665 cs->iter = iter; 666 } 667 668 /* Unmap and put previous page of userspace buffer */ 669 static void fuse_copy_finish(struct fuse_copy_state *cs) 670 { 671 if (cs->currbuf) { 672 struct pipe_buffer *buf = cs->currbuf; 673 674 if (cs->write) 675 buf->len = PAGE_SIZE - cs->len; 676 cs->currbuf = NULL; 677 } else if (cs->pg) { 678 if (cs->write) { 679 flush_dcache_page(cs->pg); 680 set_page_dirty_lock(cs->pg); 681 } 682 put_page(cs->pg); 683 } 684 cs->pg = NULL; 685 } 686 687 /* 688 * Get another pagefull of userspace buffer, and map it to kernel 689 * address space, and lock request 690 */ 691 static int fuse_copy_fill(struct fuse_copy_state *cs) 692 { 693 struct page *page; 694 int err; 695 696 err = unlock_request(cs->req); 697 if (err) 698 return err; 699 700 fuse_copy_finish(cs); 701 if (cs->pipebufs) { 702 struct pipe_buffer *buf = cs->pipebufs; 703 704 if (!cs->write) { 705 err = pipe_buf_confirm(cs->pipe, buf); 706 if (err) 707 return err; 708 709 BUG_ON(!cs->nr_segs); 710 cs->currbuf = buf; 711 cs->pg = buf->page; 712 cs->offset = buf->offset; 713 cs->len = buf->len; 714 cs->pipebufs++; 715 cs->nr_segs--; 716 } else { 717 if (cs->nr_segs >= cs->pipe->max_usage) 718 return -EIO; 719 720 page = alloc_page(GFP_HIGHUSER); 721 if (!page) 722 return -ENOMEM; 723 724 buf->page = page; 725 buf->offset = 0; 726 buf->len = 0; 727 728 cs->currbuf = buf; 729 cs->pg = page; 730 cs->offset = 0; 731 cs->len = PAGE_SIZE; 732 cs->pipebufs++; 733 cs->nr_segs++; 734 } 735 } else { 736 size_t off; 737 err = iov_iter_get_pages2(cs->iter, &page, PAGE_SIZE, 1, &off); 738 if (err < 0) 739 return err; 740 BUG_ON(!err); 741 cs->len = err; 742 cs->offset = off; 743 cs->pg = page; 744 } 745 746 return lock_request(cs->req); 747 } 748 749 /* Do as much copy to/from userspace buffer as we can */ 750 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 751 { 752 unsigned ncpy = min(*size, cs->len); 753 if (val) { 754 void *pgaddr = kmap_local_page(cs->pg); 755 void *buf = pgaddr + cs->offset; 756 757 if (cs->write) 758 memcpy(buf, *val, ncpy); 759 else 760 memcpy(*val, buf, ncpy); 761 762 kunmap_local(pgaddr); 763 *val += ncpy; 764 } 765 *size -= ncpy; 766 cs->len -= ncpy; 767 cs->offset += ncpy; 768 return ncpy; 769 } 770 771 static int fuse_check_folio(struct folio *folio) 772 { 773 if (folio_mapped(folio) || 774 folio->mapping != NULL || 775 (folio->flags & PAGE_FLAGS_CHECK_AT_PREP & 776 ~(1 << PG_locked | 777 1 << PG_referenced | 778 1 << PG_lru | 779 1 << PG_active | 780 1 << PG_workingset | 781 1 << PG_reclaim | 782 1 << PG_waiters | 783 LRU_GEN_MASK | LRU_REFS_MASK))) { 784 dump_page(&folio->page, "fuse: trying to steal weird page"); 785 return 1; 786 } 787 return 0; 788 } 789 790 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 791 { 792 int err; 793 struct folio *oldfolio = page_folio(*pagep); 794 struct folio *newfolio; 795 struct pipe_buffer *buf = cs->pipebufs; 796 797 folio_get(oldfolio); 798 err = unlock_request(cs->req); 799 if (err) 800 goto out_put_old; 801 802 fuse_copy_finish(cs); 803 804 err = pipe_buf_confirm(cs->pipe, buf); 805 if (err) 806 goto out_put_old; 807 808 BUG_ON(!cs->nr_segs); 809 cs->currbuf = buf; 810 cs->len = buf->len; 811 cs->pipebufs++; 812 cs->nr_segs--; 813 814 if (cs->len != PAGE_SIZE) 815 goto out_fallback; 816 817 if (!pipe_buf_try_steal(cs->pipe, buf)) 818 goto out_fallback; 819 820 newfolio = page_folio(buf->page); 821 822 folio_clear_uptodate(newfolio); 823 folio_clear_mappedtodisk(newfolio); 824 825 if (fuse_check_folio(newfolio) != 0) 826 goto out_fallback_unlock; 827 828 /* 829 * This is a new and locked page, it shouldn't be mapped or 830 * have any special flags on it 831 */ 832 if (WARN_ON(folio_mapped(oldfolio))) 833 goto out_fallback_unlock; 834 if (WARN_ON(folio_has_private(oldfolio))) 835 goto out_fallback_unlock; 836 if (WARN_ON(folio_test_dirty(oldfolio) || 837 folio_test_writeback(oldfolio))) 838 goto out_fallback_unlock; 839 if (WARN_ON(folio_test_mlocked(oldfolio))) 840 goto out_fallback_unlock; 841 842 replace_page_cache_folio(oldfolio, newfolio); 843 844 folio_get(newfolio); 845 846 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 847 folio_add_lru(newfolio); 848 849 /* 850 * Release while we have extra ref on stolen page. Otherwise 851 * anon_pipe_buf_release() might think the page can be reused. 852 */ 853 pipe_buf_release(cs->pipe, buf); 854 855 err = 0; 856 spin_lock(&cs->req->waitq.lock); 857 if (test_bit(FR_ABORTED, &cs->req->flags)) 858 err = -ENOENT; 859 else 860 *pagep = &newfolio->page; 861 spin_unlock(&cs->req->waitq.lock); 862 863 if (err) { 864 folio_unlock(newfolio); 865 folio_put(newfolio); 866 goto out_put_old; 867 } 868 869 folio_unlock(oldfolio); 870 /* Drop ref for ap->pages[] array */ 871 folio_put(oldfolio); 872 cs->len = 0; 873 874 err = 0; 875 out_put_old: 876 /* Drop ref obtained in this function */ 877 folio_put(oldfolio); 878 return err; 879 880 out_fallback_unlock: 881 folio_unlock(newfolio); 882 out_fallback: 883 cs->pg = buf->page; 884 cs->offset = buf->offset; 885 886 err = lock_request(cs->req); 887 if (!err) 888 err = 1; 889 890 goto out_put_old; 891 } 892 893 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 894 unsigned offset, unsigned count) 895 { 896 struct pipe_buffer *buf; 897 int err; 898 899 if (cs->nr_segs >= cs->pipe->max_usage) 900 return -EIO; 901 902 get_page(page); 903 err = unlock_request(cs->req); 904 if (err) { 905 put_page(page); 906 return err; 907 } 908 909 fuse_copy_finish(cs); 910 911 buf = cs->pipebufs; 912 buf->page = page; 913 buf->offset = offset; 914 buf->len = count; 915 916 cs->pipebufs++; 917 cs->nr_segs++; 918 cs->len = 0; 919 920 return 0; 921 } 922 923 /* 924 * Copy a page in the request to/from the userspace buffer. Must be 925 * done atomically 926 */ 927 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 928 unsigned offset, unsigned count, int zeroing) 929 { 930 int err; 931 struct page *page = *pagep; 932 933 if (page && zeroing && count < PAGE_SIZE) 934 clear_highpage(page); 935 936 while (count) { 937 if (cs->write && cs->pipebufs && page) { 938 /* 939 * Can't control lifetime of pipe buffers, so always 940 * copy user pages. 941 */ 942 if (cs->req->args->user_pages) { 943 err = fuse_copy_fill(cs); 944 if (err) 945 return err; 946 } else { 947 return fuse_ref_page(cs, page, offset, count); 948 } 949 } else if (!cs->len) { 950 if (cs->move_pages && page && 951 offset == 0 && count == PAGE_SIZE) { 952 err = fuse_try_move_page(cs, pagep); 953 if (err <= 0) 954 return err; 955 } else { 956 err = fuse_copy_fill(cs); 957 if (err) 958 return err; 959 } 960 } 961 if (page) { 962 void *mapaddr = kmap_local_page(page); 963 void *buf = mapaddr + offset; 964 offset += fuse_copy_do(cs, &buf, &count); 965 kunmap_local(mapaddr); 966 } else 967 offset += fuse_copy_do(cs, NULL, &count); 968 } 969 if (page && !cs->write) 970 flush_dcache_page(page); 971 return 0; 972 } 973 974 /* Copy pages in the request to/from userspace buffer */ 975 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 976 int zeroing) 977 { 978 unsigned i; 979 struct fuse_req *req = cs->req; 980 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args); 981 982 983 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) { 984 int err; 985 unsigned int offset = ap->descs[i].offset; 986 unsigned int count = min(nbytes, ap->descs[i].length); 987 988 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing); 989 if (err) 990 return err; 991 992 nbytes -= count; 993 } 994 return 0; 995 } 996 997 /* Copy a single argument in the request to/from userspace buffer */ 998 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 999 { 1000 while (size) { 1001 if (!cs->len) { 1002 int err = fuse_copy_fill(cs); 1003 if (err) 1004 return err; 1005 } 1006 fuse_copy_do(cs, &val, &size); 1007 } 1008 return 0; 1009 } 1010 1011 /* Copy request arguments to/from userspace buffer */ 1012 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1013 unsigned argpages, struct fuse_arg *args, 1014 int zeroing) 1015 { 1016 int err = 0; 1017 unsigned i; 1018 1019 for (i = 0; !err && i < numargs; i++) { 1020 struct fuse_arg *arg = &args[i]; 1021 if (i == numargs - 1 && argpages) 1022 err = fuse_copy_pages(cs, arg->size, zeroing); 1023 else 1024 err = fuse_copy_one(cs, arg->value, arg->size); 1025 } 1026 return err; 1027 } 1028 1029 static int forget_pending(struct fuse_iqueue *fiq) 1030 { 1031 return fiq->forget_list_head.next != NULL; 1032 } 1033 1034 static int request_pending(struct fuse_iqueue *fiq) 1035 { 1036 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1037 forget_pending(fiq); 1038 } 1039 1040 /* 1041 * Transfer an interrupt request to userspace 1042 * 1043 * Unlike other requests this is assembled on demand, without a need 1044 * to allocate a separate fuse_req structure. 1045 * 1046 * Called with fiq->lock held, releases it 1047 */ 1048 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1049 struct fuse_copy_state *cs, 1050 size_t nbytes, struct fuse_req *req) 1051 __releases(fiq->lock) 1052 { 1053 struct fuse_in_header ih; 1054 struct fuse_interrupt_in arg; 1055 unsigned reqsize = sizeof(ih) + sizeof(arg); 1056 int err; 1057 1058 list_del_init(&req->intr_entry); 1059 memset(&ih, 0, sizeof(ih)); 1060 memset(&arg, 0, sizeof(arg)); 1061 ih.len = reqsize; 1062 ih.opcode = FUSE_INTERRUPT; 1063 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT); 1064 arg.unique = req->in.h.unique; 1065 1066 spin_unlock(&fiq->lock); 1067 if (nbytes < reqsize) 1068 return -EINVAL; 1069 1070 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1071 if (!err) 1072 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1073 fuse_copy_finish(cs); 1074 1075 return err ? err : reqsize; 1076 } 1077 1078 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq, 1079 unsigned int max, 1080 unsigned int *countp) 1081 { 1082 struct fuse_forget_link *head = fiq->forget_list_head.next; 1083 struct fuse_forget_link **newhead = &head; 1084 unsigned count; 1085 1086 for (count = 0; *newhead != NULL && count < max; count++) 1087 newhead = &(*newhead)->next; 1088 1089 fiq->forget_list_head.next = *newhead; 1090 *newhead = NULL; 1091 if (fiq->forget_list_head.next == NULL) 1092 fiq->forget_list_tail = &fiq->forget_list_head; 1093 1094 if (countp != NULL) 1095 *countp = count; 1096 1097 return head; 1098 } 1099 EXPORT_SYMBOL(fuse_dequeue_forget); 1100 1101 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1102 struct fuse_copy_state *cs, 1103 size_t nbytes) 1104 __releases(fiq->lock) 1105 { 1106 int err; 1107 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL); 1108 struct fuse_forget_in arg = { 1109 .nlookup = forget->forget_one.nlookup, 1110 }; 1111 struct fuse_in_header ih = { 1112 .opcode = FUSE_FORGET, 1113 .nodeid = forget->forget_one.nodeid, 1114 .unique = fuse_get_unique(fiq), 1115 .len = sizeof(ih) + sizeof(arg), 1116 }; 1117 1118 spin_unlock(&fiq->lock); 1119 kfree(forget); 1120 if (nbytes < ih.len) 1121 return -EINVAL; 1122 1123 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1124 if (!err) 1125 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1126 fuse_copy_finish(cs); 1127 1128 if (err) 1129 return err; 1130 1131 return ih.len; 1132 } 1133 1134 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1135 struct fuse_copy_state *cs, size_t nbytes) 1136 __releases(fiq->lock) 1137 { 1138 int err; 1139 unsigned max_forgets; 1140 unsigned count; 1141 struct fuse_forget_link *head; 1142 struct fuse_batch_forget_in arg = { .count = 0 }; 1143 struct fuse_in_header ih = { 1144 .opcode = FUSE_BATCH_FORGET, 1145 .unique = fuse_get_unique(fiq), 1146 .len = sizeof(ih) + sizeof(arg), 1147 }; 1148 1149 if (nbytes < ih.len) { 1150 spin_unlock(&fiq->lock); 1151 return -EINVAL; 1152 } 1153 1154 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1155 head = fuse_dequeue_forget(fiq, max_forgets, &count); 1156 spin_unlock(&fiq->lock); 1157 1158 arg.count = count; 1159 ih.len += count * sizeof(struct fuse_forget_one); 1160 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1161 if (!err) 1162 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1163 1164 while (head) { 1165 struct fuse_forget_link *forget = head; 1166 1167 if (!err) { 1168 err = fuse_copy_one(cs, &forget->forget_one, 1169 sizeof(forget->forget_one)); 1170 } 1171 head = forget->next; 1172 kfree(forget); 1173 } 1174 1175 fuse_copy_finish(cs); 1176 1177 if (err) 1178 return err; 1179 1180 return ih.len; 1181 } 1182 1183 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1184 struct fuse_copy_state *cs, 1185 size_t nbytes) 1186 __releases(fiq->lock) 1187 { 1188 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1189 return fuse_read_single_forget(fiq, cs, nbytes); 1190 else 1191 return fuse_read_batch_forget(fiq, cs, nbytes); 1192 } 1193 1194 /* 1195 * Read a single request into the userspace filesystem's buffer. This 1196 * function waits until a request is available, then removes it from 1197 * the pending list and copies request data to userspace buffer. If 1198 * no reply is needed (FORGET) or request has been aborted or there 1199 * was an error during the copying then it's finished by calling 1200 * fuse_request_end(). Otherwise add it to the processing list, and set 1201 * the 'sent' flag. 1202 */ 1203 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1204 struct fuse_copy_state *cs, size_t nbytes) 1205 { 1206 ssize_t err; 1207 struct fuse_conn *fc = fud->fc; 1208 struct fuse_iqueue *fiq = &fc->iq; 1209 struct fuse_pqueue *fpq = &fud->pq; 1210 struct fuse_req *req; 1211 struct fuse_args *args; 1212 unsigned reqsize; 1213 unsigned int hash; 1214 1215 /* 1216 * Require sane minimum read buffer - that has capacity for fixed part 1217 * of any request header + negotiated max_write room for data. 1218 * 1219 * Historically libfuse reserves 4K for fixed header room, but e.g. 1220 * GlusterFS reserves only 80 bytes 1221 * 1222 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)` 1223 * 1224 * which is the absolute minimum any sane filesystem should be using 1225 * for header room. 1226 */ 1227 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 1228 sizeof(struct fuse_in_header) + 1229 sizeof(struct fuse_write_in) + 1230 fc->max_write)) 1231 return -EINVAL; 1232 1233 restart: 1234 for (;;) { 1235 spin_lock(&fiq->lock); 1236 if (!fiq->connected || request_pending(fiq)) 1237 break; 1238 spin_unlock(&fiq->lock); 1239 1240 if (file->f_flags & O_NONBLOCK) 1241 return -EAGAIN; 1242 err = wait_event_interruptible_exclusive(fiq->waitq, 1243 !fiq->connected || request_pending(fiq)); 1244 if (err) 1245 return err; 1246 } 1247 1248 if (!fiq->connected) { 1249 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1250 goto err_unlock; 1251 } 1252 1253 if (!list_empty(&fiq->interrupts)) { 1254 req = list_entry(fiq->interrupts.next, struct fuse_req, 1255 intr_entry); 1256 return fuse_read_interrupt(fiq, cs, nbytes, req); 1257 } 1258 1259 if (forget_pending(fiq)) { 1260 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1261 return fuse_read_forget(fc, fiq, cs, nbytes); 1262 1263 if (fiq->forget_batch <= -8) 1264 fiq->forget_batch = 16; 1265 } 1266 1267 req = list_entry(fiq->pending.next, struct fuse_req, list); 1268 clear_bit(FR_PENDING, &req->flags); 1269 list_del_init(&req->list); 1270 spin_unlock(&fiq->lock); 1271 1272 args = req->args; 1273 reqsize = req->in.h.len; 1274 1275 /* If request is too large, reply with an error and restart the read */ 1276 if (nbytes < reqsize) { 1277 req->out.h.error = -EIO; 1278 /* SETXATTR is special, since it may contain too large data */ 1279 if (args->opcode == FUSE_SETXATTR) 1280 req->out.h.error = -E2BIG; 1281 fuse_request_end(req); 1282 goto restart; 1283 } 1284 spin_lock(&fpq->lock); 1285 /* 1286 * Must not put request on fpq->io queue after having been shut down by 1287 * fuse_abort_conn() 1288 */ 1289 if (!fpq->connected) { 1290 req->out.h.error = err = -ECONNABORTED; 1291 goto out_end; 1292 1293 } 1294 list_add(&req->list, &fpq->io); 1295 spin_unlock(&fpq->lock); 1296 cs->req = req; 1297 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h)); 1298 if (!err) 1299 err = fuse_copy_args(cs, args->in_numargs, args->in_pages, 1300 (struct fuse_arg *) args->in_args, 0); 1301 fuse_copy_finish(cs); 1302 spin_lock(&fpq->lock); 1303 clear_bit(FR_LOCKED, &req->flags); 1304 if (!fpq->connected) { 1305 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1306 goto out_end; 1307 } 1308 if (err) { 1309 req->out.h.error = -EIO; 1310 goto out_end; 1311 } 1312 if (!test_bit(FR_ISREPLY, &req->flags)) { 1313 err = reqsize; 1314 goto out_end; 1315 } 1316 hash = fuse_req_hash(req->in.h.unique); 1317 list_move_tail(&req->list, &fpq->processing[hash]); 1318 __fuse_get_request(req); 1319 set_bit(FR_SENT, &req->flags); 1320 spin_unlock(&fpq->lock); 1321 /* matches barrier in request_wait_answer() */ 1322 smp_mb__after_atomic(); 1323 if (test_bit(FR_INTERRUPTED, &req->flags)) 1324 queue_interrupt(req); 1325 fuse_put_request(req); 1326 1327 return reqsize; 1328 1329 out_end: 1330 if (!test_bit(FR_PRIVATE, &req->flags)) 1331 list_del_init(&req->list); 1332 spin_unlock(&fpq->lock); 1333 fuse_request_end(req); 1334 return err; 1335 1336 err_unlock: 1337 spin_unlock(&fiq->lock); 1338 return err; 1339 } 1340 1341 static int fuse_dev_open(struct inode *inode, struct file *file) 1342 { 1343 /* 1344 * The fuse device's file's private_data is used to hold 1345 * the fuse_conn(ection) when it is mounted, and is used to 1346 * keep track of whether the file has been mounted already. 1347 */ 1348 file->private_data = NULL; 1349 return 0; 1350 } 1351 1352 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1353 { 1354 struct fuse_copy_state cs; 1355 struct file *file = iocb->ki_filp; 1356 struct fuse_dev *fud = fuse_get_dev(file); 1357 1358 if (!fud) 1359 return -EPERM; 1360 1361 if (!user_backed_iter(to)) 1362 return -EINVAL; 1363 1364 fuse_copy_init(&cs, 1, to); 1365 1366 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1367 } 1368 1369 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1370 struct pipe_inode_info *pipe, 1371 size_t len, unsigned int flags) 1372 { 1373 int total, ret; 1374 int page_nr = 0; 1375 struct pipe_buffer *bufs; 1376 struct fuse_copy_state cs; 1377 struct fuse_dev *fud = fuse_get_dev(in); 1378 1379 if (!fud) 1380 return -EPERM; 1381 1382 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer), 1383 GFP_KERNEL); 1384 if (!bufs) 1385 return -ENOMEM; 1386 1387 fuse_copy_init(&cs, 1, NULL); 1388 cs.pipebufs = bufs; 1389 cs.pipe = pipe; 1390 ret = fuse_dev_do_read(fud, in, &cs, len); 1391 if (ret < 0) 1392 goto out; 1393 1394 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) { 1395 ret = -EIO; 1396 goto out; 1397 } 1398 1399 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1400 /* 1401 * Need to be careful about this. Having buf->ops in module 1402 * code can Oops if the buffer persists after module unload. 1403 */ 1404 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1405 bufs[page_nr].flags = 0; 1406 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1407 if (unlikely(ret < 0)) 1408 break; 1409 } 1410 if (total) 1411 ret = total; 1412 out: 1413 for (; page_nr < cs.nr_segs; page_nr++) 1414 put_page(bufs[page_nr].page); 1415 1416 kvfree(bufs); 1417 return ret; 1418 } 1419 1420 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1421 struct fuse_copy_state *cs) 1422 { 1423 struct fuse_notify_poll_wakeup_out outarg; 1424 int err = -EINVAL; 1425 1426 if (size != sizeof(outarg)) 1427 goto err; 1428 1429 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1430 if (err) 1431 goto err; 1432 1433 fuse_copy_finish(cs); 1434 return fuse_notify_poll_wakeup(fc, &outarg); 1435 1436 err: 1437 fuse_copy_finish(cs); 1438 return err; 1439 } 1440 1441 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1442 struct fuse_copy_state *cs) 1443 { 1444 struct fuse_notify_inval_inode_out outarg; 1445 int err = -EINVAL; 1446 1447 if (size != sizeof(outarg)) 1448 goto err; 1449 1450 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1451 if (err) 1452 goto err; 1453 fuse_copy_finish(cs); 1454 1455 down_read(&fc->killsb); 1456 err = fuse_reverse_inval_inode(fc, outarg.ino, 1457 outarg.off, outarg.len); 1458 up_read(&fc->killsb); 1459 return err; 1460 1461 err: 1462 fuse_copy_finish(cs); 1463 return err; 1464 } 1465 1466 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1467 struct fuse_copy_state *cs) 1468 { 1469 struct fuse_notify_inval_entry_out outarg; 1470 int err = -ENOMEM; 1471 char *buf; 1472 struct qstr name; 1473 1474 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1475 if (!buf) 1476 goto err; 1477 1478 err = -EINVAL; 1479 if (size < sizeof(outarg)) 1480 goto err; 1481 1482 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1483 if (err) 1484 goto err; 1485 1486 err = -ENAMETOOLONG; 1487 if (outarg.namelen > FUSE_NAME_MAX) 1488 goto err; 1489 1490 err = -EINVAL; 1491 if (size != sizeof(outarg) + outarg.namelen + 1) 1492 goto err; 1493 1494 name.name = buf; 1495 name.len = outarg.namelen; 1496 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1497 if (err) 1498 goto err; 1499 fuse_copy_finish(cs); 1500 buf[outarg.namelen] = 0; 1501 1502 down_read(&fc->killsb); 1503 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name, outarg.flags); 1504 up_read(&fc->killsb); 1505 kfree(buf); 1506 return err; 1507 1508 err: 1509 kfree(buf); 1510 fuse_copy_finish(cs); 1511 return err; 1512 } 1513 1514 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1515 struct fuse_copy_state *cs) 1516 { 1517 struct fuse_notify_delete_out outarg; 1518 int err = -ENOMEM; 1519 char *buf; 1520 struct qstr name; 1521 1522 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1523 if (!buf) 1524 goto err; 1525 1526 err = -EINVAL; 1527 if (size < sizeof(outarg)) 1528 goto err; 1529 1530 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1531 if (err) 1532 goto err; 1533 1534 err = -ENAMETOOLONG; 1535 if (outarg.namelen > FUSE_NAME_MAX) 1536 goto err; 1537 1538 err = -EINVAL; 1539 if (size != sizeof(outarg) + outarg.namelen + 1) 1540 goto err; 1541 1542 name.name = buf; 1543 name.len = outarg.namelen; 1544 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1545 if (err) 1546 goto err; 1547 fuse_copy_finish(cs); 1548 buf[outarg.namelen] = 0; 1549 1550 down_read(&fc->killsb); 1551 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name, 0); 1552 up_read(&fc->killsb); 1553 kfree(buf); 1554 return err; 1555 1556 err: 1557 kfree(buf); 1558 fuse_copy_finish(cs); 1559 return err; 1560 } 1561 1562 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1563 struct fuse_copy_state *cs) 1564 { 1565 struct fuse_notify_store_out outarg; 1566 struct inode *inode; 1567 struct address_space *mapping; 1568 u64 nodeid; 1569 int err; 1570 pgoff_t index; 1571 unsigned int offset; 1572 unsigned int num; 1573 loff_t file_size; 1574 loff_t end; 1575 1576 err = -EINVAL; 1577 if (size < sizeof(outarg)) 1578 goto out_finish; 1579 1580 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1581 if (err) 1582 goto out_finish; 1583 1584 err = -EINVAL; 1585 if (size - sizeof(outarg) != outarg.size) 1586 goto out_finish; 1587 1588 nodeid = outarg.nodeid; 1589 1590 down_read(&fc->killsb); 1591 1592 err = -ENOENT; 1593 inode = fuse_ilookup(fc, nodeid, NULL); 1594 if (!inode) 1595 goto out_up_killsb; 1596 1597 mapping = inode->i_mapping; 1598 index = outarg.offset >> PAGE_SHIFT; 1599 offset = outarg.offset & ~PAGE_MASK; 1600 file_size = i_size_read(inode); 1601 end = outarg.offset + outarg.size; 1602 if (end > file_size) { 1603 file_size = end; 1604 fuse_write_update_attr(inode, file_size, outarg.size); 1605 } 1606 1607 num = outarg.size; 1608 while (num) { 1609 struct page *page; 1610 unsigned int this_num; 1611 1612 err = -ENOMEM; 1613 page = find_or_create_page(mapping, index, 1614 mapping_gfp_mask(mapping)); 1615 if (!page) 1616 goto out_iput; 1617 1618 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1619 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1620 if (!PageUptodate(page) && !err && offset == 0 && 1621 (this_num == PAGE_SIZE || file_size == end)) { 1622 zero_user_segment(page, this_num, PAGE_SIZE); 1623 SetPageUptodate(page); 1624 } 1625 unlock_page(page); 1626 put_page(page); 1627 1628 if (err) 1629 goto out_iput; 1630 1631 num -= this_num; 1632 offset = 0; 1633 index++; 1634 } 1635 1636 err = 0; 1637 1638 out_iput: 1639 iput(inode); 1640 out_up_killsb: 1641 up_read(&fc->killsb); 1642 out_finish: 1643 fuse_copy_finish(cs); 1644 return err; 1645 } 1646 1647 struct fuse_retrieve_args { 1648 struct fuse_args_pages ap; 1649 struct fuse_notify_retrieve_in inarg; 1650 }; 1651 1652 static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args, 1653 int error) 1654 { 1655 struct fuse_retrieve_args *ra = 1656 container_of(args, typeof(*ra), ap.args); 1657 1658 release_pages(ra->ap.pages, ra->ap.num_pages); 1659 kfree(ra); 1660 } 1661 1662 static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode, 1663 struct fuse_notify_retrieve_out *outarg) 1664 { 1665 int err; 1666 struct address_space *mapping = inode->i_mapping; 1667 pgoff_t index; 1668 loff_t file_size; 1669 unsigned int num; 1670 unsigned int offset; 1671 size_t total_len = 0; 1672 unsigned int num_pages; 1673 struct fuse_conn *fc = fm->fc; 1674 struct fuse_retrieve_args *ra; 1675 size_t args_size = sizeof(*ra); 1676 struct fuse_args_pages *ap; 1677 struct fuse_args *args; 1678 1679 offset = outarg->offset & ~PAGE_MASK; 1680 file_size = i_size_read(inode); 1681 1682 num = min(outarg->size, fc->max_write); 1683 if (outarg->offset > file_size) 1684 num = 0; 1685 else if (outarg->offset + num > file_size) 1686 num = file_size - outarg->offset; 1687 1688 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1689 num_pages = min(num_pages, fc->max_pages); 1690 1691 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0])); 1692 1693 ra = kzalloc(args_size, GFP_KERNEL); 1694 if (!ra) 1695 return -ENOMEM; 1696 1697 ap = &ra->ap; 1698 ap->pages = (void *) (ra + 1); 1699 ap->descs = (void *) (ap->pages + num_pages); 1700 1701 args = &ap->args; 1702 args->nodeid = outarg->nodeid; 1703 args->opcode = FUSE_NOTIFY_REPLY; 1704 args->in_numargs = 2; 1705 args->in_pages = true; 1706 args->end = fuse_retrieve_end; 1707 1708 index = outarg->offset >> PAGE_SHIFT; 1709 1710 while (num && ap->num_pages < num_pages) { 1711 struct page *page; 1712 unsigned int this_num; 1713 1714 page = find_get_page(mapping, index); 1715 if (!page) 1716 break; 1717 1718 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1719 ap->pages[ap->num_pages] = page; 1720 ap->descs[ap->num_pages].offset = offset; 1721 ap->descs[ap->num_pages].length = this_num; 1722 ap->num_pages++; 1723 1724 offset = 0; 1725 num -= this_num; 1726 total_len += this_num; 1727 index++; 1728 } 1729 ra->inarg.offset = outarg->offset; 1730 ra->inarg.size = total_len; 1731 args->in_args[0].size = sizeof(ra->inarg); 1732 args->in_args[0].value = &ra->inarg; 1733 args->in_args[1].size = total_len; 1734 1735 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique); 1736 if (err) 1737 fuse_retrieve_end(fm, args, err); 1738 1739 return err; 1740 } 1741 1742 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1743 struct fuse_copy_state *cs) 1744 { 1745 struct fuse_notify_retrieve_out outarg; 1746 struct fuse_mount *fm; 1747 struct inode *inode; 1748 u64 nodeid; 1749 int err; 1750 1751 err = -EINVAL; 1752 if (size != sizeof(outarg)) 1753 goto copy_finish; 1754 1755 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1756 if (err) 1757 goto copy_finish; 1758 1759 fuse_copy_finish(cs); 1760 1761 down_read(&fc->killsb); 1762 err = -ENOENT; 1763 nodeid = outarg.nodeid; 1764 1765 inode = fuse_ilookup(fc, nodeid, &fm); 1766 if (inode) { 1767 err = fuse_retrieve(fm, inode, &outarg); 1768 iput(inode); 1769 } 1770 up_read(&fc->killsb); 1771 1772 return err; 1773 1774 copy_finish: 1775 fuse_copy_finish(cs); 1776 return err; 1777 } 1778 1779 /* 1780 * Resending all processing queue requests. 1781 * 1782 * During a FUSE daemon panics and failover, it is possible for some inflight 1783 * requests to be lost and never returned. As a result, applications awaiting 1784 * replies would become stuck forever. To address this, we can use notification 1785 * to trigger resending of these pending requests to the FUSE daemon, ensuring 1786 * they are properly processed again. 1787 * 1788 * Please note that this strategy is applicable only to idempotent requests or 1789 * if the FUSE daemon takes careful measures to avoid processing duplicated 1790 * non-idempotent requests. 1791 */ 1792 static void fuse_resend(struct fuse_conn *fc) 1793 { 1794 struct fuse_dev *fud; 1795 struct fuse_req *req, *next; 1796 struct fuse_iqueue *fiq = &fc->iq; 1797 LIST_HEAD(to_queue); 1798 unsigned int i; 1799 1800 spin_lock(&fc->lock); 1801 if (!fc->connected) { 1802 spin_unlock(&fc->lock); 1803 return; 1804 } 1805 1806 list_for_each_entry(fud, &fc->devices, entry) { 1807 struct fuse_pqueue *fpq = &fud->pq; 1808 1809 spin_lock(&fpq->lock); 1810 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 1811 list_splice_tail_init(&fpq->processing[i], &to_queue); 1812 spin_unlock(&fpq->lock); 1813 } 1814 spin_unlock(&fc->lock); 1815 1816 list_for_each_entry_safe(req, next, &to_queue, list) { 1817 set_bit(FR_PENDING, &req->flags); 1818 clear_bit(FR_SENT, &req->flags); 1819 /* mark the request as resend request */ 1820 req->in.h.unique |= FUSE_UNIQUE_RESEND; 1821 } 1822 1823 spin_lock(&fiq->lock); 1824 if (!fiq->connected) { 1825 spin_unlock(&fiq->lock); 1826 list_for_each_entry(req, &to_queue, list) 1827 clear_bit(FR_PENDING, &req->flags); 1828 end_requests(&to_queue); 1829 return; 1830 } 1831 /* iq and pq requests are both oldest to newest */ 1832 list_splice(&to_queue, &fiq->pending); 1833 fiq->ops->wake_pending_and_unlock(fiq); 1834 } 1835 1836 static int fuse_notify_resend(struct fuse_conn *fc) 1837 { 1838 fuse_resend(fc); 1839 return 0; 1840 } 1841 1842 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1843 unsigned int size, struct fuse_copy_state *cs) 1844 { 1845 /* Don't try to move pages (yet) */ 1846 cs->move_pages = 0; 1847 1848 switch (code) { 1849 case FUSE_NOTIFY_POLL: 1850 return fuse_notify_poll(fc, size, cs); 1851 1852 case FUSE_NOTIFY_INVAL_INODE: 1853 return fuse_notify_inval_inode(fc, size, cs); 1854 1855 case FUSE_NOTIFY_INVAL_ENTRY: 1856 return fuse_notify_inval_entry(fc, size, cs); 1857 1858 case FUSE_NOTIFY_STORE: 1859 return fuse_notify_store(fc, size, cs); 1860 1861 case FUSE_NOTIFY_RETRIEVE: 1862 return fuse_notify_retrieve(fc, size, cs); 1863 1864 case FUSE_NOTIFY_DELETE: 1865 return fuse_notify_delete(fc, size, cs); 1866 1867 case FUSE_NOTIFY_RESEND: 1868 return fuse_notify_resend(fc); 1869 1870 default: 1871 fuse_copy_finish(cs); 1872 return -EINVAL; 1873 } 1874 } 1875 1876 /* Look up request on processing list by unique ID */ 1877 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1878 { 1879 unsigned int hash = fuse_req_hash(unique); 1880 struct fuse_req *req; 1881 1882 list_for_each_entry(req, &fpq->processing[hash], list) { 1883 if (req->in.h.unique == unique) 1884 return req; 1885 } 1886 return NULL; 1887 } 1888 1889 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, 1890 unsigned nbytes) 1891 { 1892 unsigned reqsize = sizeof(struct fuse_out_header); 1893 1894 reqsize += fuse_len_args(args->out_numargs, args->out_args); 1895 1896 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar)) 1897 return -EINVAL; 1898 else if (reqsize > nbytes) { 1899 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1]; 1900 unsigned diffsize = reqsize - nbytes; 1901 1902 if (diffsize > lastarg->size) 1903 return -EINVAL; 1904 lastarg->size -= diffsize; 1905 } 1906 return fuse_copy_args(cs, args->out_numargs, args->out_pages, 1907 args->out_args, args->page_zeroing); 1908 } 1909 1910 /* 1911 * Write a single reply to a request. First the header is copied from 1912 * the write buffer. The request is then searched on the processing 1913 * list by the unique ID found in the header. If found, then remove 1914 * it from the list and copy the rest of the buffer to the request. 1915 * The request is finished by calling fuse_request_end(). 1916 */ 1917 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1918 struct fuse_copy_state *cs, size_t nbytes) 1919 { 1920 int err; 1921 struct fuse_conn *fc = fud->fc; 1922 struct fuse_pqueue *fpq = &fud->pq; 1923 struct fuse_req *req; 1924 struct fuse_out_header oh; 1925 1926 err = -EINVAL; 1927 if (nbytes < sizeof(struct fuse_out_header)) 1928 goto out; 1929 1930 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1931 if (err) 1932 goto copy_finish; 1933 1934 err = -EINVAL; 1935 if (oh.len != nbytes) 1936 goto copy_finish; 1937 1938 /* 1939 * Zero oh.unique indicates unsolicited notification message 1940 * and error contains notification code. 1941 */ 1942 if (!oh.unique) { 1943 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1944 goto out; 1945 } 1946 1947 err = -EINVAL; 1948 if (oh.error <= -512 || oh.error > 0) 1949 goto copy_finish; 1950 1951 spin_lock(&fpq->lock); 1952 req = NULL; 1953 if (fpq->connected) 1954 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT); 1955 1956 err = -ENOENT; 1957 if (!req) { 1958 spin_unlock(&fpq->lock); 1959 goto copy_finish; 1960 } 1961 1962 /* Is it an interrupt reply ID? */ 1963 if (oh.unique & FUSE_INT_REQ_BIT) { 1964 __fuse_get_request(req); 1965 spin_unlock(&fpq->lock); 1966 1967 err = 0; 1968 if (nbytes != sizeof(struct fuse_out_header)) 1969 err = -EINVAL; 1970 else if (oh.error == -ENOSYS) 1971 fc->no_interrupt = 1; 1972 else if (oh.error == -EAGAIN) 1973 err = queue_interrupt(req); 1974 1975 fuse_put_request(req); 1976 1977 goto copy_finish; 1978 } 1979 1980 clear_bit(FR_SENT, &req->flags); 1981 list_move(&req->list, &fpq->io); 1982 req->out.h = oh; 1983 set_bit(FR_LOCKED, &req->flags); 1984 spin_unlock(&fpq->lock); 1985 cs->req = req; 1986 if (!req->args->page_replace) 1987 cs->move_pages = 0; 1988 1989 if (oh.error) 1990 err = nbytes != sizeof(oh) ? -EINVAL : 0; 1991 else 1992 err = copy_out_args(cs, req->args, nbytes); 1993 fuse_copy_finish(cs); 1994 1995 spin_lock(&fpq->lock); 1996 clear_bit(FR_LOCKED, &req->flags); 1997 if (!fpq->connected) 1998 err = -ENOENT; 1999 else if (err) 2000 req->out.h.error = -EIO; 2001 if (!test_bit(FR_PRIVATE, &req->flags)) 2002 list_del_init(&req->list); 2003 spin_unlock(&fpq->lock); 2004 2005 fuse_request_end(req); 2006 out: 2007 return err ? err : nbytes; 2008 2009 copy_finish: 2010 fuse_copy_finish(cs); 2011 goto out; 2012 } 2013 2014 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 2015 { 2016 struct fuse_copy_state cs; 2017 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 2018 2019 if (!fud) 2020 return -EPERM; 2021 2022 if (!user_backed_iter(from)) 2023 return -EINVAL; 2024 2025 fuse_copy_init(&cs, 0, from); 2026 2027 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 2028 } 2029 2030 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 2031 struct file *out, loff_t *ppos, 2032 size_t len, unsigned int flags) 2033 { 2034 unsigned int head, tail, mask, count; 2035 unsigned nbuf; 2036 unsigned idx; 2037 struct pipe_buffer *bufs; 2038 struct fuse_copy_state cs; 2039 struct fuse_dev *fud; 2040 size_t rem; 2041 ssize_t ret; 2042 2043 fud = fuse_get_dev(out); 2044 if (!fud) 2045 return -EPERM; 2046 2047 pipe_lock(pipe); 2048 2049 head = pipe->head; 2050 tail = pipe->tail; 2051 mask = pipe->ring_size - 1; 2052 count = head - tail; 2053 2054 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL); 2055 if (!bufs) { 2056 pipe_unlock(pipe); 2057 return -ENOMEM; 2058 } 2059 2060 nbuf = 0; 2061 rem = 0; 2062 for (idx = tail; idx != head && rem < len; idx++) 2063 rem += pipe->bufs[idx & mask].len; 2064 2065 ret = -EINVAL; 2066 if (rem < len) 2067 goto out_free; 2068 2069 rem = len; 2070 while (rem) { 2071 struct pipe_buffer *ibuf; 2072 struct pipe_buffer *obuf; 2073 2074 if (WARN_ON(nbuf >= count || tail == head)) 2075 goto out_free; 2076 2077 ibuf = &pipe->bufs[tail & mask]; 2078 obuf = &bufs[nbuf]; 2079 2080 if (rem >= ibuf->len) { 2081 *obuf = *ibuf; 2082 ibuf->ops = NULL; 2083 tail++; 2084 pipe->tail = tail; 2085 } else { 2086 if (!pipe_buf_get(pipe, ibuf)) 2087 goto out_free; 2088 2089 *obuf = *ibuf; 2090 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 2091 obuf->len = rem; 2092 ibuf->offset += obuf->len; 2093 ibuf->len -= obuf->len; 2094 } 2095 nbuf++; 2096 rem -= obuf->len; 2097 } 2098 pipe_unlock(pipe); 2099 2100 fuse_copy_init(&cs, 0, NULL); 2101 cs.pipebufs = bufs; 2102 cs.nr_segs = nbuf; 2103 cs.pipe = pipe; 2104 2105 if (flags & SPLICE_F_MOVE) 2106 cs.move_pages = 1; 2107 2108 ret = fuse_dev_do_write(fud, &cs, len); 2109 2110 pipe_lock(pipe); 2111 out_free: 2112 for (idx = 0; idx < nbuf; idx++) { 2113 struct pipe_buffer *buf = &bufs[idx]; 2114 2115 if (buf->ops) 2116 pipe_buf_release(pipe, buf); 2117 } 2118 pipe_unlock(pipe); 2119 2120 kvfree(bufs); 2121 return ret; 2122 } 2123 2124 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait) 2125 { 2126 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 2127 struct fuse_iqueue *fiq; 2128 struct fuse_dev *fud = fuse_get_dev(file); 2129 2130 if (!fud) 2131 return EPOLLERR; 2132 2133 fiq = &fud->fc->iq; 2134 poll_wait(file, &fiq->waitq, wait); 2135 2136 spin_lock(&fiq->lock); 2137 if (!fiq->connected) 2138 mask = EPOLLERR; 2139 else if (request_pending(fiq)) 2140 mask |= EPOLLIN | EPOLLRDNORM; 2141 spin_unlock(&fiq->lock); 2142 2143 return mask; 2144 } 2145 2146 /* Abort all requests on the given list (pending or processing) */ 2147 static void end_requests(struct list_head *head) 2148 { 2149 while (!list_empty(head)) { 2150 struct fuse_req *req; 2151 req = list_entry(head->next, struct fuse_req, list); 2152 req->out.h.error = -ECONNABORTED; 2153 clear_bit(FR_SENT, &req->flags); 2154 list_del_init(&req->list); 2155 fuse_request_end(req); 2156 } 2157 } 2158 2159 static void end_polls(struct fuse_conn *fc) 2160 { 2161 struct rb_node *p; 2162 2163 p = rb_first(&fc->polled_files); 2164 2165 while (p) { 2166 struct fuse_file *ff; 2167 ff = rb_entry(p, struct fuse_file, polled_node); 2168 wake_up_interruptible_all(&ff->poll_wait); 2169 2170 p = rb_next(p); 2171 } 2172 } 2173 2174 /* 2175 * Abort all requests. 2176 * 2177 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2178 * filesystem. 2179 * 2180 * The same effect is usually achievable through killing the filesystem daemon 2181 * and all users of the filesystem. The exception is the combination of an 2182 * asynchronous request and the tricky deadlock (see 2183 * Documentation/filesystems/fuse.rst). 2184 * 2185 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2186 * requests, they should be finished off immediately. Locked requests will be 2187 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2188 * requests. It is possible that some request will finish before we can. This 2189 * is OK, the request will in that case be removed from the list before we touch 2190 * it. 2191 */ 2192 void fuse_abort_conn(struct fuse_conn *fc) 2193 { 2194 struct fuse_iqueue *fiq = &fc->iq; 2195 2196 spin_lock(&fc->lock); 2197 if (fc->connected) { 2198 struct fuse_dev *fud; 2199 struct fuse_req *req, *next; 2200 LIST_HEAD(to_end); 2201 unsigned int i; 2202 2203 /* Background queuing checks fc->connected under bg_lock */ 2204 spin_lock(&fc->bg_lock); 2205 fc->connected = 0; 2206 spin_unlock(&fc->bg_lock); 2207 2208 fuse_set_initialized(fc); 2209 list_for_each_entry(fud, &fc->devices, entry) { 2210 struct fuse_pqueue *fpq = &fud->pq; 2211 2212 spin_lock(&fpq->lock); 2213 fpq->connected = 0; 2214 list_for_each_entry_safe(req, next, &fpq->io, list) { 2215 req->out.h.error = -ECONNABORTED; 2216 spin_lock(&req->waitq.lock); 2217 set_bit(FR_ABORTED, &req->flags); 2218 if (!test_bit(FR_LOCKED, &req->flags)) { 2219 set_bit(FR_PRIVATE, &req->flags); 2220 __fuse_get_request(req); 2221 list_move(&req->list, &to_end); 2222 } 2223 spin_unlock(&req->waitq.lock); 2224 } 2225 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2226 list_splice_tail_init(&fpq->processing[i], 2227 &to_end); 2228 spin_unlock(&fpq->lock); 2229 } 2230 spin_lock(&fc->bg_lock); 2231 fc->blocked = 0; 2232 fc->max_background = UINT_MAX; 2233 flush_bg_queue(fc); 2234 spin_unlock(&fc->bg_lock); 2235 2236 spin_lock(&fiq->lock); 2237 fiq->connected = 0; 2238 list_for_each_entry(req, &fiq->pending, list) 2239 clear_bit(FR_PENDING, &req->flags); 2240 list_splice_tail_init(&fiq->pending, &to_end); 2241 while (forget_pending(fiq)) 2242 kfree(fuse_dequeue_forget(fiq, 1, NULL)); 2243 wake_up_all(&fiq->waitq); 2244 spin_unlock(&fiq->lock); 2245 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2246 end_polls(fc); 2247 wake_up_all(&fc->blocked_waitq); 2248 spin_unlock(&fc->lock); 2249 2250 end_requests(&to_end); 2251 } else { 2252 spin_unlock(&fc->lock); 2253 } 2254 } 2255 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2256 2257 void fuse_wait_aborted(struct fuse_conn *fc) 2258 { 2259 /* matches implicit memory barrier in fuse_drop_waiting() */ 2260 smp_mb(); 2261 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0); 2262 } 2263 2264 int fuse_dev_release(struct inode *inode, struct file *file) 2265 { 2266 struct fuse_dev *fud = fuse_get_dev(file); 2267 2268 if (fud) { 2269 struct fuse_conn *fc = fud->fc; 2270 struct fuse_pqueue *fpq = &fud->pq; 2271 LIST_HEAD(to_end); 2272 unsigned int i; 2273 2274 spin_lock(&fpq->lock); 2275 WARN_ON(!list_empty(&fpq->io)); 2276 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2277 list_splice_init(&fpq->processing[i], &to_end); 2278 spin_unlock(&fpq->lock); 2279 2280 end_requests(&to_end); 2281 2282 /* Are we the last open device? */ 2283 if (atomic_dec_and_test(&fc->dev_count)) { 2284 WARN_ON(fc->iq.fasync != NULL); 2285 fuse_abort_conn(fc); 2286 } 2287 fuse_dev_free(fud); 2288 } 2289 return 0; 2290 } 2291 EXPORT_SYMBOL_GPL(fuse_dev_release); 2292 2293 static int fuse_dev_fasync(int fd, struct file *file, int on) 2294 { 2295 struct fuse_dev *fud = fuse_get_dev(file); 2296 2297 if (!fud) 2298 return -EPERM; 2299 2300 /* No locking - fasync_helper does its own locking */ 2301 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2302 } 2303 2304 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2305 { 2306 struct fuse_dev *fud; 2307 2308 if (new->private_data) 2309 return -EINVAL; 2310 2311 fud = fuse_dev_alloc_install(fc); 2312 if (!fud) 2313 return -ENOMEM; 2314 2315 new->private_data = fud; 2316 atomic_inc(&fc->dev_count); 2317 2318 return 0; 2319 } 2320 2321 static long fuse_dev_ioctl_clone(struct file *file, __u32 __user *argp) 2322 { 2323 int res; 2324 int oldfd; 2325 struct fuse_dev *fud = NULL; 2326 struct fd f; 2327 2328 if (get_user(oldfd, argp)) 2329 return -EFAULT; 2330 2331 f = fdget(oldfd); 2332 if (!f.file) 2333 return -EINVAL; 2334 2335 /* 2336 * Check against file->f_op because CUSE 2337 * uses the same ioctl handler. 2338 */ 2339 if (f.file->f_op == file->f_op) 2340 fud = fuse_get_dev(f.file); 2341 2342 res = -EINVAL; 2343 if (fud) { 2344 mutex_lock(&fuse_mutex); 2345 res = fuse_device_clone(fud->fc, file); 2346 mutex_unlock(&fuse_mutex); 2347 } 2348 2349 fdput(f); 2350 return res; 2351 } 2352 2353 static long fuse_dev_ioctl_backing_open(struct file *file, 2354 struct fuse_backing_map __user *argp) 2355 { 2356 struct fuse_dev *fud = fuse_get_dev(file); 2357 struct fuse_backing_map map; 2358 2359 if (!fud) 2360 return -EPERM; 2361 2362 if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 2363 return -EOPNOTSUPP; 2364 2365 if (copy_from_user(&map, argp, sizeof(map))) 2366 return -EFAULT; 2367 2368 return fuse_backing_open(fud->fc, &map); 2369 } 2370 2371 static long fuse_dev_ioctl_backing_close(struct file *file, __u32 __user *argp) 2372 { 2373 struct fuse_dev *fud = fuse_get_dev(file); 2374 int backing_id; 2375 2376 if (!fud) 2377 return -EPERM; 2378 2379 if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) 2380 return -EOPNOTSUPP; 2381 2382 if (get_user(backing_id, argp)) 2383 return -EFAULT; 2384 2385 return fuse_backing_close(fud->fc, backing_id); 2386 } 2387 2388 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2389 unsigned long arg) 2390 { 2391 void __user *argp = (void __user *)arg; 2392 2393 switch (cmd) { 2394 case FUSE_DEV_IOC_CLONE: 2395 return fuse_dev_ioctl_clone(file, argp); 2396 2397 case FUSE_DEV_IOC_BACKING_OPEN: 2398 return fuse_dev_ioctl_backing_open(file, argp); 2399 2400 case FUSE_DEV_IOC_BACKING_CLOSE: 2401 return fuse_dev_ioctl_backing_close(file, argp); 2402 2403 default: 2404 return -ENOTTY; 2405 } 2406 } 2407 2408 const struct file_operations fuse_dev_operations = { 2409 .owner = THIS_MODULE, 2410 .open = fuse_dev_open, 2411 .llseek = no_llseek, 2412 .read_iter = fuse_dev_read, 2413 .splice_read = fuse_dev_splice_read, 2414 .write_iter = fuse_dev_write, 2415 .splice_write = fuse_dev_splice_write, 2416 .poll = fuse_dev_poll, 2417 .release = fuse_dev_release, 2418 .fasync = fuse_dev_fasync, 2419 .unlocked_ioctl = fuse_dev_ioctl, 2420 .compat_ioctl = compat_ptr_ioctl, 2421 }; 2422 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2423 2424 static struct miscdevice fuse_miscdevice = { 2425 .minor = FUSE_MINOR, 2426 .name = "fuse", 2427 .fops = &fuse_dev_operations, 2428 }; 2429 2430 int __init fuse_dev_init(void) 2431 { 2432 int err = -ENOMEM; 2433 fuse_req_cachep = kmem_cache_create("fuse_request", 2434 sizeof(struct fuse_req), 2435 0, 0, NULL); 2436 if (!fuse_req_cachep) 2437 goto out; 2438 2439 err = misc_register(&fuse_miscdevice); 2440 if (err) 2441 goto out_cache_clean; 2442 2443 return 0; 2444 2445 out_cache_clean: 2446 kmem_cache_destroy(fuse_req_cachep); 2447 out: 2448 return err; 2449 } 2450 2451 void fuse_dev_cleanup(void) 2452 { 2453 misc_deregister(&fuse_miscdevice); 2454 kmem_cache_destroy(fuse_req_cachep); 2455 } 2456