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