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