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_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 } 51 52 static struct fuse_req *fuse_request_alloc(gfp_t flags) 53 { 54 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags); 55 if (req) 56 fuse_request_init(req); 57 58 return req; 59 } 60 61 static void fuse_request_free(struct fuse_req *req) 62 { 63 kmem_cache_free(fuse_req_cachep, req); 64 } 65 66 static void __fuse_get_request(struct fuse_req *req) 67 { 68 refcount_inc(&req->count); 69 } 70 71 /* Must be called with > 1 refcount */ 72 static void __fuse_put_request(struct fuse_req *req) 73 { 74 refcount_dec(&req->count); 75 } 76 77 void fuse_set_initialized(struct fuse_conn *fc) 78 { 79 /* Make sure stores before this are seen on another CPU */ 80 smp_wmb(); 81 fc->initialized = 1; 82 } 83 84 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 85 { 86 return !fc->initialized || (for_background && fc->blocked); 87 } 88 89 static void fuse_drop_waiting(struct fuse_conn *fc) 90 { 91 /* 92 * lockess check of fc->connected is okay, because atomic_dec_and_test() 93 * provides a memory barrier mached with the one in fuse_wait_aborted() 94 * to ensure no wake-up is missed. 95 */ 96 if (atomic_dec_and_test(&fc->num_waiting) && 97 !READ_ONCE(fc->connected)) { 98 /* wake up aborters */ 99 wake_up_all(&fc->blocked_waitq); 100 } 101 } 102 103 static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 104 105 static struct fuse_req *fuse_get_req(struct fuse_conn *fc, bool for_background) 106 { 107 struct fuse_req *req; 108 int err; 109 atomic_inc(&fc->num_waiting); 110 111 if (fuse_block_alloc(fc, for_background)) { 112 err = -EINTR; 113 if (wait_event_killable_exclusive(fc->blocked_waitq, 114 !fuse_block_alloc(fc, for_background))) 115 goto out; 116 } 117 /* Matches smp_wmb() in fuse_set_initialized() */ 118 smp_rmb(); 119 120 err = -ENOTCONN; 121 if (!fc->connected) 122 goto out; 123 124 err = -ECONNREFUSED; 125 if (fc->conn_error) 126 goto out; 127 128 req = fuse_request_alloc(GFP_KERNEL); 129 err = -ENOMEM; 130 if (!req) { 131 if (for_background) 132 wake_up(&fc->blocked_waitq); 133 goto out; 134 } 135 136 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid()); 137 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid()); 138 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 139 140 __set_bit(FR_WAITING, &req->flags); 141 if (for_background) 142 __set_bit(FR_BACKGROUND, &req->flags); 143 144 if (unlikely(req->in.h.uid == ((uid_t)-1) || 145 req->in.h.gid == ((gid_t)-1))) { 146 fuse_put_request(fc, req); 147 return ERR_PTR(-EOVERFLOW); 148 } 149 return req; 150 151 out: 152 fuse_drop_waiting(fc); 153 return ERR_PTR(err); 154 } 155 156 static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) 157 { 158 if (refcount_dec_and_test(&req->count)) { 159 if (test_bit(FR_BACKGROUND, &req->flags)) { 160 /* 161 * We get here in the unlikely case that a background 162 * request was allocated but not sent 163 */ 164 spin_lock(&fc->bg_lock); 165 if (!fc->blocked) 166 wake_up(&fc->blocked_waitq); 167 spin_unlock(&fc->bg_lock); 168 } 169 170 if (test_bit(FR_WAITING, &req->flags)) { 171 __clear_bit(FR_WAITING, &req->flags); 172 fuse_drop_waiting(fc); 173 } 174 175 fuse_request_free(req); 176 } 177 } 178 179 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args) 180 { 181 unsigned nbytes = 0; 182 unsigned i; 183 184 for (i = 0; i < numargs; i++) 185 nbytes += args[i].size; 186 187 return nbytes; 188 } 189 EXPORT_SYMBOL_GPL(fuse_len_args); 190 191 u64 fuse_get_unique(struct fuse_iqueue *fiq) 192 { 193 fiq->reqctr += FUSE_REQ_ID_STEP; 194 return fiq->reqctr; 195 } 196 EXPORT_SYMBOL_GPL(fuse_get_unique); 197 198 static unsigned int fuse_req_hash(u64 unique) 199 { 200 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS); 201 } 202 203 /** 204 * A new request is available, wake fiq->waitq 205 */ 206 static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq) 207 __releases(fiq->lock) 208 { 209 wake_up(&fiq->waitq); 210 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 211 spin_unlock(&fiq->lock); 212 } 213 214 const struct fuse_iqueue_ops fuse_dev_fiq_ops = { 215 .wake_forget_and_unlock = fuse_dev_wake_and_unlock, 216 .wake_interrupt_and_unlock = fuse_dev_wake_and_unlock, 217 .wake_pending_and_unlock = fuse_dev_wake_and_unlock, 218 }; 219 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops); 220 221 static void queue_request_and_unlock(struct fuse_iqueue *fiq, 222 struct fuse_req *req) 223 __releases(fiq->lock) 224 { 225 req->in.h.len = sizeof(struct fuse_in_header) + 226 fuse_len_args(req->args->in_numargs, 227 (struct fuse_arg *) req->args->in_args); 228 list_add_tail(&req->list, &fiq->pending); 229 fiq->ops->wake_pending_and_unlock(fiq); 230 } 231 232 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 233 u64 nodeid, u64 nlookup) 234 { 235 struct fuse_iqueue *fiq = &fc->iq; 236 237 forget->forget_one.nodeid = nodeid; 238 forget->forget_one.nlookup = nlookup; 239 240 spin_lock(&fiq->lock); 241 if (fiq->connected) { 242 fiq->forget_list_tail->next = forget; 243 fiq->forget_list_tail = forget; 244 fiq->ops->wake_forget_and_unlock(fiq); 245 } else { 246 kfree(forget); 247 spin_unlock(&fiq->lock); 248 } 249 } 250 251 static void flush_bg_queue(struct fuse_conn *fc) 252 { 253 struct fuse_iqueue *fiq = &fc->iq; 254 255 while (fc->active_background < fc->max_background && 256 !list_empty(&fc->bg_queue)) { 257 struct fuse_req *req; 258 259 req = list_first_entry(&fc->bg_queue, struct fuse_req, list); 260 list_del(&req->list); 261 fc->active_background++; 262 spin_lock(&fiq->lock); 263 req->in.h.unique = fuse_get_unique(fiq); 264 queue_request_and_unlock(fiq, req); 265 } 266 } 267 268 /* 269 * This function is called when a request is finished. Either a reply 270 * has arrived or it was aborted (and not yet sent) or some error 271 * occurred during communication with userspace, or the device file 272 * was closed. The requester thread is woken up (if still waiting), 273 * the 'end' callback is called if given, else the reference to the 274 * request is released 275 */ 276 void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req) 277 { 278 struct fuse_iqueue *fiq = &fc->iq; 279 280 if (test_and_set_bit(FR_FINISHED, &req->flags)) 281 goto put_request; 282 283 /* 284 * test_and_set_bit() implies smp_mb() between bit 285 * changing and below intr_entry check. Pairs with 286 * smp_mb() from queue_interrupt(). 287 */ 288 if (!list_empty(&req->intr_entry)) { 289 spin_lock(&fiq->lock); 290 list_del_init(&req->intr_entry); 291 spin_unlock(&fiq->lock); 292 } 293 WARN_ON(test_bit(FR_PENDING, &req->flags)); 294 WARN_ON(test_bit(FR_SENT, &req->flags)); 295 if (test_bit(FR_BACKGROUND, &req->flags)) { 296 spin_lock(&fc->bg_lock); 297 clear_bit(FR_BACKGROUND, &req->flags); 298 if (fc->num_background == fc->max_background) { 299 fc->blocked = 0; 300 wake_up(&fc->blocked_waitq); 301 } else if (!fc->blocked) { 302 /* 303 * Wake up next waiter, if any. It's okay to use 304 * waitqueue_active(), as we've already synced up 305 * fc->blocked with waiters with the wake_up() call 306 * above. 307 */ 308 if (waitqueue_active(&fc->blocked_waitq)) 309 wake_up(&fc->blocked_waitq); 310 } 311 312 if (fc->num_background == fc->congestion_threshold && fc->sb) { 313 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 314 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 315 } 316 fc->num_background--; 317 fc->active_background--; 318 flush_bg_queue(fc); 319 spin_unlock(&fc->bg_lock); 320 } else { 321 /* Wake up waiter sleeping in request_wait_answer() */ 322 wake_up(&req->waitq); 323 } 324 325 if (test_bit(FR_ASYNC, &req->flags)) 326 req->args->end(fc, req->args, req->out.h.error); 327 put_request: 328 fuse_put_request(fc, req); 329 } 330 EXPORT_SYMBOL_GPL(fuse_request_end); 331 332 static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) 333 { 334 spin_lock(&fiq->lock); 335 /* Check for we've sent request to interrupt this req */ 336 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) { 337 spin_unlock(&fiq->lock); 338 return -EINVAL; 339 } 340 341 if (list_empty(&req->intr_entry)) { 342 list_add_tail(&req->intr_entry, &fiq->interrupts); 343 /* 344 * Pairs with smp_mb() implied by test_and_set_bit() 345 * from request_end(). 346 */ 347 smp_mb(); 348 if (test_bit(FR_FINISHED, &req->flags)) { 349 list_del_init(&req->intr_entry); 350 spin_unlock(&fiq->lock); 351 return 0; 352 } 353 fiq->ops->wake_interrupt_and_unlock(fiq); 354 } else { 355 spin_unlock(&fiq->lock); 356 } 357 return 0; 358 } 359 360 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) 361 { 362 struct fuse_iqueue *fiq = &fc->iq; 363 int err; 364 365 if (!fc->no_interrupt) { 366 /* Any signal may interrupt this */ 367 err = wait_event_interruptible(req->waitq, 368 test_bit(FR_FINISHED, &req->flags)); 369 if (!err) 370 return; 371 372 set_bit(FR_INTERRUPTED, &req->flags); 373 /* matches barrier in fuse_dev_do_read() */ 374 smp_mb__after_atomic(); 375 if (test_bit(FR_SENT, &req->flags)) 376 queue_interrupt(fiq, req); 377 } 378 379 if (!test_bit(FR_FORCE, &req->flags)) { 380 /* Only fatal signals may interrupt this */ 381 err = wait_event_killable(req->waitq, 382 test_bit(FR_FINISHED, &req->flags)); 383 if (!err) 384 return; 385 386 spin_lock(&fiq->lock); 387 /* Request is not yet in userspace, bail out */ 388 if (test_bit(FR_PENDING, &req->flags)) { 389 list_del(&req->list); 390 spin_unlock(&fiq->lock); 391 __fuse_put_request(req); 392 req->out.h.error = -EINTR; 393 return; 394 } 395 spin_unlock(&fiq->lock); 396 } 397 398 /* 399 * Either request is already in userspace, or it was forced. 400 * Wait it out. 401 */ 402 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags)); 403 } 404 405 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 406 { 407 struct fuse_iqueue *fiq = &fc->iq; 408 409 BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); 410 spin_lock(&fiq->lock); 411 if (!fiq->connected) { 412 spin_unlock(&fiq->lock); 413 req->out.h.error = -ENOTCONN; 414 } else { 415 req->in.h.unique = fuse_get_unique(fiq); 416 /* acquire extra reference, since request is still needed 417 after fuse_request_end() */ 418 __fuse_get_request(req); 419 queue_request_and_unlock(fiq, req); 420 421 request_wait_answer(fc, req); 422 /* Pairs with smp_wmb() in fuse_request_end() */ 423 smp_rmb(); 424 } 425 } 426 427 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) 428 { 429 if (fc->minor < 4 && args->opcode == FUSE_STATFS) 430 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE; 431 432 if (fc->minor < 9) { 433 switch (args->opcode) { 434 case FUSE_LOOKUP: 435 case FUSE_CREATE: 436 case FUSE_MKNOD: 437 case FUSE_MKDIR: 438 case FUSE_SYMLINK: 439 case FUSE_LINK: 440 args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; 441 break; 442 case FUSE_GETATTR: 443 case FUSE_SETATTR: 444 args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; 445 break; 446 } 447 } 448 if (fc->minor < 12) { 449 switch (args->opcode) { 450 case FUSE_CREATE: 451 args->in_args[0].size = sizeof(struct fuse_open_in); 452 break; 453 case FUSE_MKNOD: 454 args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; 455 break; 456 } 457 } 458 } 459 460 static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req) 461 { 462 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid()); 463 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid()); 464 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 465 } 466 467 static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args) 468 { 469 req->in.h.opcode = args->opcode; 470 req->in.h.nodeid = args->nodeid; 471 req->args = args; 472 if (args->end) 473 __set_bit(FR_ASYNC, &req->flags); 474 } 475 476 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) 477 { 478 struct fuse_req *req; 479 ssize_t ret; 480 481 if (args->force) { 482 atomic_inc(&fc->num_waiting); 483 req = fuse_request_alloc(GFP_KERNEL | __GFP_NOFAIL); 484 485 if (!args->nocreds) 486 fuse_force_creds(fc, req); 487 488 __set_bit(FR_WAITING, &req->flags); 489 __set_bit(FR_FORCE, &req->flags); 490 } else { 491 WARN_ON(args->nocreds); 492 req = fuse_get_req(fc, false); 493 if (IS_ERR(req)) 494 return PTR_ERR(req); 495 } 496 497 /* Needs to be done after fuse_get_req() so that fc->minor is valid */ 498 fuse_adjust_compat(fc, args); 499 fuse_args_to_req(req, args); 500 501 if (!args->noreply) 502 __set_bit(FR_ISREPLY, &req->flags); 503 __fuse_request_send(fc, req); 504 ret = req->out.h.error; 505 if (!ret && args->out_argvar) { 506 BUG_ON(args->out_numargs == 0); 507 ret = args->out_args[args->out_numargs - 1].size; 508 } 509 fuse_put_request(fc, req); 510 511 return ret; 512 } 513 514 static bool fuse_request_queue_background(struct fuse_conn *fc, 515 struct fuse_req *req) 516 { 517 bool queued = false; 518 519 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags)); 520 if (!test_bit(FR_WAITING, &req->flags)) { 521 __set_bit(FR_WAITING, &req->flags); 522 atomic_inc(&fc->num_waiting); 523 } 524 __set_bit(FR_ISREPLY, &req->flags); 525 spin_lock(&fc->bg_lock); 526 if (likely(fc->connected)) { 527 fc->num_background++; 528 if (fc->num_background == fc->max_background) 529 fc->blocked = 1; 530 if (fc->num_background == fc->congestion_threshold && fc->sb) { 531 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 532 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 533 } 534 list_add_tail(&req->list, &fc->bg_queue); 535 flush_bg_queue(fc); 536 queued = true; 537 } 538 spin_unlock(&fc->bg_lock); 539 540 return queued; 541 } 542 543 int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args, 544 gfp_t gfp_flags) 545 { 546 struct fuse_req *req; 547 548 if (args->force) { 549 WARN_ON(!args->nocreds); 550 req = fuse_request_alloc(gfp_flags); 551 if (!req) 552 return -ENOMEM; 553 __set_bit(FR_BACKGROUND, &req->flags); 554 } else { 555 WARN_ON(args->nocreds); 556 req = fuse_get_req(fc, true); 557 if (IS_ERR(req)) 558 return PTR_ERR(req); 559 } 560 561 fuse_args_to_req(req, args); 562 563 if (!fuse_request_queue_background(fc, req)) { 564 fuse_put_request(fc, req); 565 return -ENOTCONN; 566 } 567 568 return 0; 569 } 570 EXPORT_SYMBOL_GPL(fuse_simple_background); 571 572 static int fuse_simple_notify_reply(struct fuse_conn *fc, 573 struct fuse_args *args, u64 unique) 574 { 575 struct fuse_req *req; 576 struct fuse_iqueue *fiq = &fc->iq; 577 int err = 0; 578 579 req = fuse_get_req(fc, false); 580 if (IS_ERR(req)) 581 return PTR_ERR(req); 582 583 __clear_bit(FR_ISREPLY, &req->flags); 584 req->in.h.unique = unique; 585 586 fuse_args_to_req(req, args); 587 588 spin_lock(&fiq->lock); 589 if (fiq->connected) { 590 queue_request_and_unlock(fiq, req); 591 } else { 592 err = -ENODEV; 593 spin_unlock(&fiq->lock); 594 fuse_put_request(fc, req); 595 } 596 597 return err; 598 } 599 600 /* 601 * Lock the request. Up to the next unlock_request() there mustn't be 602 * anything that could cause a page-fault. If the request was already 603 * aborted bail out. 604 */ 605 static int lock_request(struct fuse_req *req) 606 { 607 int err = 0; 608 if (req) { 609 spin_lock(&req->waitq.lock); 610 if (test_bit(FR_ABORTED, &req->flags)) 611 err = -ENOENT; 612 else 613 set_bit(FR_LOCKED, &req->flags); 614 spin_unlock(&req->waitq.lock); 615 } 616 return err; 617 } 618 619 /* 620 * Unlock request. If it was aborted while locked, caller is responsible 621 * for unlocking and ending the request. 622 */ 623 static int unlock_request(struct fuse_req *req) 624 { 625 int err = 0; 626 if (req) { 627 spin_lock(&req->waitq.lock); 628 if (test_bit(FR_ABORTED, &req->flags)) 629 err = -ENOENT; 630 else 631 clear_bit(FR_LOCKED, &req->flags); 632 spin_unlock(&req->waitq.lock); 633 } 634 return err; 635 } 636 637 struct fuse_copy_state { 638 int write; 639 struct fuse_req *req; 640 struct iov_iter *iter; 641 struct pipe_buffer *pipebufs; 642 struct pipe_buffer *currbuf; 643 struct pipe_inode_info *pipe; 644 unsigned long nr_segs; 645 struct page *pg; 646 unsigned len; 647 unsigned offset; 648 unsigned move_pages:1; 649 }; 650 651 static void fuse_copy_init(struct fuse_copy_state *cs, int write, 652 struct iov_iter *iter) 653 { 654 memset(cs, 0, sizeof(*cs)); 655 cs->write = write; 656 cs->iter = iter; 657 } 658 659 /* Unmap and put previous page of userspace buffer */ 660 static void fuse_copy_finish(struct fuse_copy_state *cs) 661 { 662 if (cs->currbuf) { 663 struct pipe_buffer *buf = cs->currbuf; 664 665 if (cs->write) 666 buf->len = PAGE_SIZE - cs->len; 667 cs->currbuf = NULL; 668 } else if (cs->pg) { 669 if (cs->write) { 670 flush_dcache_page(cs->pg); 671 set_page_dirty_lock(cs->pg); 672 } 673 put_page(cs->pg); 674 } 675 cs->pg = NULL; 676 } 677 678 /* 679 * Get another pagefull of userspace buffer, and map it to kernel 680 * address space, and lock request 681 */ 682 static int fuse_copy_fill(struct fuse_copy_state *cs) 683 { 684 struct page *page; 685 int err; 686 687 err = unlock_request(cs->req); 688 if (err) 689 return err; 690 691 fuse_copy_finish(cs); 692 if (cs->pipebufs) { 693 struct pipe_buffer *buf = cs->pipebufs; 694 695 if (!cs->write) { 696 err = pipe_buf_confirm(cs->pipe, buf); 697 if (err) 698 return err; 699 700 BUG_ON(!cs->nr_segs); 701 cs->currbuf = buf; 702 cs->pg = buf->page; 703 cs->offset = buf->offset; 704 cs->len = buf->len; 705 cs->pipebufs++; 706 cs->nr_segs--; 707 } else { 708 if (cs->nr_segs >= cs->pipe->max_usage) 709 return -EIO; 710 711 page = alloc_page(GFP_HIGHUSER); 712 if (!page) 713 return -ENOMEM; 714 715 buf->page = page; 716 buf->offset = 0; 717 buf->len = 0; 718 719 cs->currbuf = buf; 720 cs->pg = page; 721 cs->offset = 0; 722 cs->len = PAGE_SIZE; 723 cs->pipebufs++; 724 cs->nr_segs++; 725 } 726 } else { 727 size_t off; 728 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off); 729 if (err < 0) 730 return err; 731 BUG_ON(!err); 732 cs->len = err; 733 cs->offset = off; 734 cs->pg = page; 735 iov_iter_advance(cs->iter, err); 736 } 737 738 return lock_request(cs->req); 739 } 740 741 /* Do as much copy to/from userspace buffer as we can */ 742 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 743 { 744 unsigned ncpy = min(*size, cs->len); 745 if (val) { 746 void *pgaddr = kmap_atomic(cs->pg); 747 void *buf = pgaddr + cs->offset; 748 749 if (cs->write) 750 memcpy(buf, *val, ncpy); 751 else 752 memcpy(*val, buf, ncpy); 753 754 kunmap_atomic(pgaddr); 755 *val += ncpy; 756 } 757 *size -= ncpy; 758 cs->len -= ncpy; 759 cs->offset += ncpy; 760 return ncpy; 761 } 762 763 static int fuse_check_page(struct page *page) 764 { 765 if (page_mapcount(page) || 766 page->mapping != NULL || 767 page_count(page) != 1 || 768 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 769 ~(1 << PG_locked | 770 1 << PG_referenced | 771 1 << PG_uptodate | 772 1 << PG_lru | 773 1 << PG_active | 774 1 << PG_reclaim))) { 775 pr_warn("trying to steal weird page\n"); 776 pr_warn(" page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping); 777 return 1; 778 } 779 return 0; 780 } 781 782 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 783 { 784 int err; 785 struct page *oldpage = *pagep; 786 struct page *newpage; 787 struct pipe_buffer *buf = cs->pipebufs; 788 789 err = unlock_request(cs->req); 790 if (err) 791 return err; 792 793 fuse_copy_finish(cs); 794 795 err = pipe_buf_confirm(cs->pipe, buf); 796 if (err) 797 return err; 798 799 BUG_ON(!cs->nr_segs); 800 cs->currbuf = buf; 801 cs->len = buf->len; 802 cs->pipebufs++; 803 cs->nr_segs--; 804 805 if (cs->len != PAGE_SIZE) 806 goto out_fallback; 807 808 if (pipe_buf_steal(cs->pipe, buf) != 0) 809 goto out_fallback; 810 811 newpage = buf->page; 812 813 if (!PageUptodate(newpage)) 814 SetPageUptodate(newpage); 815 816 ClearPageMappedToDisk(newpage); 817 818 if (fuse_check_page(newpage) != 0) 819 goto out_fallback_unlock; 820 821 /* 822 * This is a new and locked page, it shouldn't be mapped or 823 * have any special flags on it 824 */ 825 if (WARN_ON(page_mapped(oldpage))) 826 goto out_fallback_unlock; 827 if (WARN_ON(page_has_private(oldpage))) 828 goto out_fallback_unlock; 829 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 830 goto out_fallback_unlock; 831 if (WARN_ON(PageMlocked(oldpage))) 832 goto out_fallback_unlock; 833 834 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); 835 if (err) { 836 unlock_page(newpage); 837 return err; 838 } 839 840 get_page(newpage); 841 842 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 843 lru_cache_add_file(newpage); 844 845 err = 0; 846 spin_lock(&cs->req->waitq.lock); 847 if (test_bit(FR_ABORTED, &cs->req->flags)) 848 err = -ENOENT; 849 else 850 *pagep = newpage; 851 spin_unlock(&cs->req->waitq.lock); 852 853 if (err) { 854 unlock_page(newpage); 855 put_page(newpage); 856 return err; 857 } 858 859 unlock_page(oldpage); 860 put_page(oldpage); 861 cs->len = 0; 862 863 return 0; 864 865 out_fallback_unlock: 866 unlock_page(newpage); 867 out_fallback: 868 cs->pg = buf->page; 869 cs->offset = buf->offset; 870 871 err = lock_request(cs->req); 872 if (err) 873 return err; 874 875 return 1; 876 } 877 878 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 879 unsigned offset, unsigned count) 880 { 881 struct pipe_buffer *buf; 882 int err; 883 884 if (cs->nr_segs >= cs->pipe->max_usage) 885 return -EIO; 886 887 err = unlock_request(cs->req); 888 if (err) 889 return err; 890 891 fuse_copy_finish(cs); 892 893 buf = cs->pipebufs; 894 get_page(page); 895 buf->page = page; 896 buf->offset = offset; 897 buf->len = count; 898 899 cs->pipebufs++; 900 cs->nr_segs++; 901 cs->len = 0; 902 903 return 0; 904 } 905 906 /* 907 * Copy a page in the request to/from the userspace buffer. Must be 908 * done atomically 909 */ 910 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 911 unsigned offset, unsigned count, int zeroing) 912 { 913 int err; 914 struct page *page = *pagep; 915 916 if (page && zeroing && count < PAGE_SIZE) 917 clear_highpage(page); 918 919 while (count) { 920 if (cs->write && cs->pipebufs && page) { 921 return fuse_ref_page(cs, page, offset, count); 922 } else if (!cs->len) { 923 if (cs->move_pages && page && 924 offset == 0 && count == PAGE_SIZE) { 925 err = fuse_try_move_page(cs, pagep); 926 if (err <= 0) 927 return err; 928 } else { 929 err = fuse_copy_fill(cs); 930 if (err) 931 return err; 932 } 933 } 934 if (page) { 935 void *mapaddr = kmap_atomic(page); 936 void *buf = mapaddr + offset; 937 offset += fuse_copy_do(cs, &buf, &count); 938 kunmap_atomic(mapaddr); 939 } else 940 offset += fuse_copy_do(cs, NULL, &count); 941 } 942 if (page && !cs->write) 943 flush_dcache_page(page); 944 return 0; 945 } 946 947 /* Copy pages in the request to/from userspace buffer */ 948 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 949 int zeroing) 950 { 951 unsigned i; 952 struct fuse_req *req = cs->req; 953 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args); 954 955 956 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) { 957 int err; 958 unsigned int offset = ap->descs[i].offset; 959 unsigned int count = min(nbytes, ap->descs[i].length); 960 961 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing); 962 if (err) 963 return err; 964 965 nbytes -= count; 966 } 967 return 0; 968 } 969 970 /* Copy a single argument in the request to/from userspace buffer */ 971 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 972 { 973 while (size) { 974 if (!cs->len) { 975 int err = fuse_copy_fill(cs); 976 if (err) 977 return err; 978 } 979 fuse_copy_do(cs, &val, &size); 980 } 981 return 0; 982 } 983 984 /* Copy request arguments to/from userspace buffer */ 985 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 986 unsigned argpages, struct fuse_arg *args, 987 int zeroing) 988 { 989 int err = 0; 990 unsigned i; 991 992 for (i = 0; !err && i < numargs; i++) { 993 struct fuse_arg *arg = &args[i]; 994 if (i == numargs - 1 && argpages) 995 err = fuse_copy_pages(cs, arg->size, zeroing); 996 else 997 err = fuse_copy_one(cs, arg->value, arg->size); 998 } 999 return err; 1000 } 1001 1002 static int forget_pending(struct fuse_iqueue *fiq) 1003 { 1004 return fiq->forget_list_head.next != NULL; 1005 } 1006 1007 static int request_pending(struct fuse_iqueue *fiq) 1008 { 1009 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1010 forget_pending(fiq); 1011 } 1012 1013 /* 1014 * Transfer an interrupt request to userspace 1015 * 1016 * Unlike other requests this is assembled on demand, without a need 1017 * to allocate a separate fuse_req structure. 1018 * 1019 * Called with fiq->lock held, releases it 1020 */ 1021 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1022 struct fuse_copy_state *cs, 1023 size_t nbytes, struct fuse_req *req) 1024 __releases(fiq->lock) 1025 { 1026 struct fuse_in_header ih; 1027 struct fuse_interrupt_in arg; 1028 unsigned reqsize = sizeof(ih) + sizeof(arg); 1029 int err; 1030 1031 list_del_init(&req->intr_entry); 1032 memset(&ih, 0, sizeof(ih)); 1033 memset(&arg, 0, sizeof(arg)); 1034 ih.len = reqsize; 1035 ih.opcode = FUSE_INTERRUPT; 1036 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT); 1037 arg.unique = req->in.h.unique; 1038 1039 spin_unlock(&fiq->lock); 1040 if (nbytes < reqsize) 1041 return -EINVAL; 1042 1043 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1044 if (!err) 1045 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1046 fuse_copy_finish(cs); 1047 1048 return err ? err : reqsize; 1049 } 1050 1051 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq, 1052 unsigned int max, 1053 unsigned int *countp) 1054 { 1055 struct fuse_forget_link *head = fiq->forget_list_head.next; 1056 struct fuse_forget_link **newhead = &head; 1057 unsigned count; 1058 1059 for (count = 0; *newhead != NULL && count < max; count++) 1060 newhead = &(*newhead)->next; 1061 1062 fiq->forget_list_head.next = *newhead; 1063 *newhead = NULL; 1064 if (fiq->forget_list_head.next == NULL) 1065 fiq->forget_list_tail = &fiq->forget_list_head; 1066 1067 if (countp != NULL) 1068 *countp = count; 1069 1070 return head; 1071 } 1072 EXPORT_SYMBOL(fuse_dequeue_forget); 1073 1074 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1075 struct fuse_copy_state *cs, 1076 size_t nbytes) 1077 __releases(fiq->lock) 1078 { 1079 int err; 1080 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL); 1081 struct fuse_forget_in arg = { 1082 .nlookup = forget->forget_one.nlookup, 1083 }; 1084 struct fuse_in_header ih = { 1085 .opcode = FUSE_FORGET, 1086 .nodeid = forget->forget_one.nodeid, 1087 .unique = fuse_get_unique(fiq), 1088 .len = sizeof(ih) + sizeof(arg), 1089 }; 1090 1091 spin_unlock(&fiq->lock); 1092 kfree(forget); 1093 if (nbytes < ih.len) 1094 return -EINVAL; 1095 1096 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1097 if (!err) 1098 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1099 fuse_copy_finish(cs); 1100 1101 if (err) 1102 return err; 1103 1104 return ih.len; 1105 } 1106 1107 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1108 struct fuse_copy_state *cs, size_t nbytes) 1109 __releases(fiq->lock) 1110 { 1111 int err; 1112 unsigned max_forgets; 1113 unsigned count; 1114 struct fuse_forget_link *head; 1115 struct fuse_batch_forget_in arg = { .count = 0 }; 1116 struct fuse_in_header ih = { 1117 .opcode = FUSE_BATCH_FORGET, 1118 .unique = fuse_get_unique(fiq), 1119 .len = sizeof(ih) + sizeof(arg), 1120 }; 1121 1122 if (nbytes < ih.len) { 1123 spin_unlock(&fiq->lock); 1124 return -EINVAL; 1125 } 1126 1127 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1128 head = fuse_dequeue_forget(fiq, max_forgets, &count); 1129 spin_unlock(&fiq->lock); 1130 1131 arg.count = count; 1132 ih.len += count * sizeof(struct fuse_forget_one); 1133 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1134 if (!err) 1135 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1136 1137 while (head) { 1138 struct fuse_forget_link *forget = head; 1139 1140 if (!err) { 1141 err = fuse_copy_one(cs, &forget->forget_one, 1142 sizeof(forget->forget_one)); 1143 } 1144 head = forget->next; 1145 kfree(forget); 1146 } 1147 1148 fuse_copy_finish(cs); 1149 1150 if (err) 1151 return err; 1152 1153 return ih.len; 1154 } 1155 1156 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1157 struct fuse_copy_state *cs, 1158 size_t nbytes) 1159 __releases(fiq->lock) 1160 { 1161 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1162 return fuse_read_single_forget(fiq, cs, nbytes); 1163 else 1164 return fuse_read_batch_forget(fiq, cs, nbytes); 1165 } 1166 1167 /* 1168 * Read a single request into the userspace filesystem's buffer. This 1169 * function waits until a request is available, then removes it from 1170 * the pending list and copies request data to userspace buffer. If 1171 * no reply is needed (FORGET) or request has been aborted or there 1172 * was an error during the copying then it's finished by calling 1173 * fuse_request_end(). Otherwise add it to the processing list, and set 1174 * the 'sent' flag. 1175 */ 1176 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1177 struct fuse_copy_state *cs, size_t nbytes) 1178 { 1179 ssize_t err; 1180 struct fuse_conn *fc = fud->fc; 1181 struct fuse_iqueue *fiq = &fc->iq; 1182 struct fuse_pqueue *fpq = &fud->pq; 1183 struct fuse_req *req; 1184 struct fuse_args *args; 1185 unsigned reqsize; 1186 unsigned int hash; 1187 1188 /* 1189 * Require sane minimum read buffer - that has capacity for fixed part 1190 * of any request header + negotiated max_write room for data. 1191 * 1192 * Historically libfuse reserves 4K for fixed header room, but e.g. 1193 * GlusterFS reserves only 80 bytes 1194 * 1195 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)` 1196 * 1197 * which is the absolute minimum any sane filesystem should be using 1198 * for header room. 1199 */ 1200 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 1201 sizeof(struct fuse_in_header) + 1202 sizeof(struct fuse_write_in) + 1203 fc->max_write)) 1204 return -EINVAL; 1205 1206 restart: 1207 for (;;) { 1208 spin_lock(&fiq->lock); 1209 if (!fiq->connected || request_pending(fiq)) 1210 break; 1211 spin_unlock(&fiq->lock); 1212 1213 if (file->f_flags & O_NONBLOCK) 1214 return -EAGAIN; 1215 err = wait_event_interruptible_exclusive(fiq->waitq, 1216 !fiq->connected || request_pending(fiq)); 1217 if (err) 1218 return err; 1219 } 1220 1221 if (!fiq->connected) { 1222 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1223 goto err_unlock; 1224 } 1225 1226 if (!list_empty(&fiq->interrupts)) { 1227 req = list_entry(fiq->interrupts.next, struct fuse_req, 1228 intr_entry); 1229 return fuse_read_interrupt(fiq, cs, nbytes, req); 1230 } 1231 1232 if (forget_pending(fiq)) { 1233 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1234 return fuse_read_forget(fc, fiq, cs, nbytes); 1235 1236 if (fiq->forget_batch <= -8) 1237 fiq->forget_batch = 16; 1238 } 1239 1240 req = list_entry(fiq->pending.next, struct fuse_req, list); 1241 clear_bit(FR_PENDING, &req->flags); 1242 list_del_init(&req->list); 1243 spin_unlock(&fiq->lock); 1244 1245 args = req->args; 1246 reqsize = req->in.h.len; 1247 1248 /* If request is too large, reply with an error and restart the read */ 1249 if (nbytes < reqsize) { 1250 req->out.h.error = -EIO; 1251 /* SETXATTR is special, since it may contain too large data */ 1252 if (args->opcode == FUSE_SETXATTR) 1253 req->out.h.error = -E2BIG; 1254 fuse_request_end(fc, req); 1255 goto restart; 1256 } 1257 spin_lock(&fpq->lock); 1258 list_add(&req->list, &fpq->io); 1259 spin_unlock(&fpq->lock); 1260 cs->req = req; 1261 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h)); 1262 if (!err) 1263 err = fuse_copy_args(cs, args->in_numargs, args->in_pages, 1264 (struct fuse_arg *) args->in_args, 0); 1265 fuse_copy_finish(cs); 1266 spin_lock(&fpq->lock); 1267 clear_bit(FR_LOCKED, &req->flags); 1268 if (!fpq->connected) { 1269 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1270 goto out_end; 1271 } 1272 if (err) { 1273 req->out.h.error = -EIO; 1274 goto out_end; 1275 } 1276 if (!test_bit(FR_ISREPLY, &req->flags)) { 1277 err = reqsize; 1278 goto out_end; 1279 } 1280 hash = fuse_req_hash(req->in.h.unique); 1281 list_move_tail(&req->list, &fpq->processing[hash]); 1282 __fuse_get_request(req); 1283 set_bit(FR_SENT, &req->flags); 1284 spin_unlock(&fpq->lock); 1285 /* matches barrier in request_wait_answer() */ 1286 smp_mb__after_atomic(); 1287 if (test_bit(FR_INTERRUPTED, &req->flags)) 1288 queue_interrupt(fiq, req); 1289 fuse_put_request(fc, req); 1290 1291 return reqsize; 1292 1293 out_end: 1294 if (!test_bit(FR_PRIVATE, &req->flags)) 1295 list_del_init(&req->list); 1296 spin_unlock(&fpq->lock); 1297 fuse_request_end(fc, req); 1298 return err; 1299 1300 err_unlock: 1301 spin_unlock(&fiq->lock); 1302 return err; 1303 } 1304 1305 static int fuse_dev_open(struct inode *inode, struct file *file) 1306 { 1307 /* 1308 * The fuse device's file's private_data is used to hold 1309 * the fuse_conn(ection) when it is mounted, and is used to 1310 * keep track of whether the file has been mounted already. 1311 */ 1312 file->private_data = NULL; 1313 return 0; 1314 } 1315 1316 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1317 { 1318 struct fuse_copy_state cs; 1319 struct file *file = iocb->ki_filp; 1320 struct fuse_dev *fud = fuse_get_dev(file); 1321 1322 if (!fud) 1323 return -EPERM; 1324 1325 if (!iter_is_iovec(to)) 1326 return -EINVAL; 1327 1328 fuse_copy_init(&cs, 1, to); 1329 1330 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1331 } 1332 1333 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1334 struct pipe_inode_info *pipe, 1335 size_t len, unsigned int flags) 1336 { 1337 int total, ret; 1338 int page_nr = 0; 1339 struct pipe_buffer *bufs; 1340 struct fuse_copy_state cs; 1341 struct fuse_dev *fud = fuse_get_dev(in); 1342 1343 if (!fud) 1344 return -EPERM; 1345 1346 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer), 1347 GFP_KERNEL); 1348 if (!bufs) 1349 return -ENOMEM; 1350 1351 fuse_copy_init(&cs, 1, NULL); 1352 cs.pipebufs = bufs; 1353 cs.pipe = pipe; 1354 ret = fuse_dev_do_read(fud, in, &cs, len); 1355 if (ret < 0) 1356 goto out; 1357 1358 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) { 1359 ret = -EIO; 1360 goto out; 1361 } 1362 1363 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1364 /* 1365 * Need to be careful about this. Having buf->ops in module 1366 * code can Oops if the buffer persists after module unload. 1367 */ 1368 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1369 bufs[page_nr].flags = 0; 1370 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1371 if (unlikely(ret < 0)) 1372 break; 1373 } 1374 if (total) 1375 ret = total; 1376 out: 1377 for (; page_nr < cs.nr_segs; page_nr++) 1378 put_page(bufs[page_nr].page); 1379 1380 kvfree(bufs); 1381 return ret; 1382 } 1383 1384 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1385 struct fuse_copy_state *cs) 1386 { 1387 struct fuse_notify_poll_wakeup_out outarg; 1388 int err = -EINVAL; 1389 1390 if (size != sizeof(outarg)) 1391 goto err; 1392 1393 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1394 if (err) 1395 goto err; 1396 1397 fuse_copy_finish(cs); 1398 return fuse_notify_poll_wakeup(fc, &outarg); 1399 1400 err: 1401 fuse_copy_finish(cs); 1402 return err; 1403 } 1404 1405 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1406 struct fuse_copy_state *cs) 1407 { 1408 struct fuse_notify_inval_inode_out outarg; 1409 int err = -EINVAL; 1410 1411 if (size != sizeof(outarg)) 1412 goto err; 1413 1414 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1415 if (err) 1416 goto err; 1417 fuse_copy_finish(cs); 1418 1419 down_read(&fc->killsb); 1420 err = -ENOENT; 1421 if (fc->sb) { 1422 err = fuse_reverse_inval_inode(fc->sb, outarg.ino, 1423 outarg.off, outarg.len); 1424 } 1425 up_read(&fc->killsb); 1426 return err; 1427 1428 err: 1429 fuse_copy_finish(cs); 1430 return err; 1431 } 1432 1433 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1434 struct fuse_copy_state *cs) 1435 { 1436 struct fuse_notify_inval_entry_out outarg; 1437 int err = -ENOMEM; 1438 char *buf; 1439 struct qstr name; 1440 1441 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1442 if (!buf) 1443 goto err; 1444 1445 err = -EINVAL; 1446 if (size < sizeof(outarg)) 1447 goto err; 1448 1449 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1450 if (err) 1451 goto err; 1452 1453 err = -ENAMETOOLONG; 1454 if (outarg.namelen > FUSE_NAME_MAX) 1455 goto err; 1456 1457 err = -EINVAL; 1458 if (size != sizeof(outarg) + outarg.namelen + 1) 1459 goto err; 1460 1461 name.name = buf; 1462 name.len = outarg.namelen; 1463 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1464 if (err) 1465 goto err; 1466 fuse_copy_finish(cs); 1467 buf[outarg.namelen] = 0; 1468 1469 down_read(&fc->killsb); 1470 err = -ENOENT; 1471 if (fc->sb) 1472 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name); 1473 up_read(&fc->killsb); 1474 kfree(buf); 1475 return err; 1476 1477 err: 1478 kfree(buf); 1479 fuse_copy_finish(cs); 1480 return err; 1481 } 1482 1483 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1484 struct fuse_copy_state *cs) 1485 { 1486 struct fuse_notify_delete_out outarg; 1487 int err = -ENOMEM; 1488 char *buf; 1489 struct qstr name; 1490 1491 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1492 if (!buf) 1493 goto err; 1494 1495 err = -EINVAL; 1496 if (size < sizeof(outarg)) 1497 goto err; 1498 1499 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1500 if (err) 1501 goto err; 1502 1503 err = -ENAMETOOLONG; 1504 if (outarg.namelen > FUSE_NAME_MAX) 1505 goto err; 1506 1507 err = -EINVAL; 1508 if (size != sizeof(outarg) + outarg.namelen + 1) 1509 goto err; 1510 1511 name.name = buf; 1512 name.len = outarg.namelen; 1513 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1514 if (err) 1515 goto err; 1516 fuse_copy_finish(cs); 1517 buf[outarg.namelen] = 0; 1518 1519 down_read(&fc->killsb); 1520 err = -ENOENT; 1521 if (fc->sb) 1522 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 1523 outarg.child, &name); 1524 up_read(&fc->killsb); 1525 kfree(buf); 1526 return err; 1527 1528 err: 1529 kfree(buf); 1530 fuse_copy_finish(cs); 1531 return err; 1532 } 1533 1534 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1535 struct fuse_copy_state *cs) 1536 { 1537 struct fuse_notify_store_out outarg; 1538 struct inode *inode; 1539 struct address_space *mapping; 1540 u64 nodeid; 1541 int err; 1542 pgoff_t index; 1543 unsigned int offset; 1544 unsigned int num; 1545 loff_t file_size; 1546 loff_t end; 1547 1548 err = -EINVAL; 1549 if (size < sizeof(outarg)) 1550 goto out_finish; 1551 1552 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1553 if (err) 1554 goto out_finish; 1555 1556 err = -EINVAL; 1557 if (size - sizeof(outarg) != outarg.size) 1558 goto out_finish; 1559 1560 nodeid = outarg.nodeid; 1561 1562 down_read(&fc->killsb); 1563 1564 err = -ENOENT; 1565 if (!fc->sb) 1566 goto out_up_killsb; 1567 1568 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1569 if (!inode) 1570 goto out_up_killsb; 1571 1572 mapping = inode->i_mapping; 1573 index = outarg.offset >> PAGE_SHIFT; 1574 offset = outarg.offset & ~PAGE_MASK; 1575 file_size = i_size_read(inode); 1576 end = outarg.offset + outarg.size; 1577 if (end > file_size) { 1578 file_size = end; 1579 fuse_write_update_size(inode, file_size); 1580 } 1581 1582 num = outarg.size; 1583 while (num) { 1584 struct page *page; 1585 unsigned int this_num; 1586 1587 err = -ENOMEM; 1588 page = find_or_create_page(mapping, index, 1589 mapping_gfp_mask(mapping)); 1590 if (!page) 1591 goto out_iput; 1592 1593 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1594 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1595 if (!err && offset == 0 && 1596 (this_num == PAGE_SIZE || file_size == end)) 1597 SetPageUptodate(page); 1598 unlock_page(page); 1599 put_page(page); 1600 1601 if (err) 1602 goto out_iput; 1603 1604 num -= this_num; 1605 offset = 0; 1606 index++; 1607 } 1608 1609 err = 0; 1610 1611 out_iput: 1612 iput(inode); 1613 out_up_killsb: 1614 up_read(&fc->killsb); 1615 out_finish: 1616 fuse_copy_finish(cs); 1617 return err; 1618 } 1619 1620 struct fuse_retrieve_args { 1621 struct fuse_args_pages ap; 1622 struct fuse_notify_retrieve_in inarg; 1623 }; 1624 1625 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_args *args, 1626 int error) 1627 { 1628 struct fuse_retrieve_args *ra = 1629 container_of(args, typeof(*ra), ap.args); 1630 1631 release_pages(ra->ap.pages, ra->ap.num_pages); 1632 kfree(ra); 1633 } 1634 1635 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, 1636 struct fuse_notify_retrieve_out *outarg) 1637 { 1638 int err; 1639 struct address_space *mapping = inode->i_mapping; 1640 pgoff_t index; 1641 loff_t file_size; 1642 unsigned int num; 1643 unsigned int offset; 1644 size_t total_len = 0; 1645 unsigned int num_pages; 1646 struct fuse_retrieve_args *ra; 1647 size_t args_size = sizeof(*ra); 1648 struct fuse_args_pages *ap; 1649 struct fuse_args *args; 1650 1651 offset = outarg->offset & ~PAGE_MASK; 1652 file_size = i_size_read(inode); 1653 1654 num = min(outarg->size, fc->max_write); 1655 if (outarg->offset > file_size) 1656 num = 0; 1657 else if (outarg->offset + num > file_size) 1658 num = file_size - outarg->offset; 1659 1660 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1661 num_pages = min(num_pages, fc->max_pages); 1662 1663 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0])); 1664 1665 ra = kzalloc(args_size, GFP_KERNEL); 1666 if (!ra) 1667 return -ENOMEM; 1668 1669 ap = &ra->ap; 1670 ap->pages = (void *) (ra + 1); 1671 ap->descs = (void *) (ap->pages + num_pages); 1672 1673 args = &ap->args; 1674 args->nodeid = outarg->nodeid; 1675 args->opcode = FUSE_NOTIFY_REPLY; 1676 args->in_numargs = 2; 1677 args->in_pages = true; 1678 args->end = fuse_retrieve_end; 1679 1680 index = outarg->offset >> PAGE_SHIFT; 1681 1682 while (num && ap->num_pages < num_pages) { 1683 struct page *page; 1684 unsigned int this_num; 1685 1686 page = find_get_page(mapping, index); 1687 if (!page) 1688 break; 1689 1690 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1691 ap->pages[ap->num_pages] = page; 1692 ap->descs[ap->num_pages].offset = offset; 1693 ap->descs[ap->num_pages].length = this_num; 1694 ap->num_pages++; 1695 1696 offset = 0; 1697 num -= this_num; 1698 total_len += this_num; 1699 index++; 1700 } 1701 ra->inarg.offset = outarg->offset; 1702 ra->inarg.size = total_len; 1703 args->in_args[0].size = sizeof(ra->inarg); 1704 args->in_args[0].value = &ra->inarg; 1705 args->in_args[1].size = total_len; 1706 1707 err = fuse_simple_notify_reply(fc, args, outarg->notify_unique); 1708 if (err) 1709 fuse_retrieve_end(fc, args, err); 1710 1711 return err; 1712 } 1713 1714 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1715 struct fuse_copy_state *cs) 1716 { 1717 struct fuse_notify_retrieve_out outarg; 1718 struct inode *inode; 1719 int err; 1720 1721 err = -EINVAL; 1722 if (size != sizeof(outarg)) 1723 goto copy_finish; 1724 1725 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1726 if (err) 1727 goto copy_finish; 1728 1729 fuse_copy_finish(cs); 1730 1731 down_read(&fc->killsb); 1732 err = -ENOENT; 1733 if (fc->sb) { 1734 u64 nodeid = outarg.nodeid; 1735 1736 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1737 if (inode) { 1738 err = fuse_retrieve(fc, inode, &outarg); 1739 iput(inode); 1740 } 1741 } 1742 up_read(&fc->killsb); 1743 1744 return err; 1745 1746 copy_finish: 1747 fuse_copy_finish(cs); 1748 return err; 1749 } 1750 1751 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1752 unsigned int size, struct fuse_copy_state *cs) 1753 { 1754 /* Don't try to move pages (yet) */ 1755 cs->move_pages = 0; 1756 1757 switch (code) { 1758 case FUSE_NOTIFY_POLL: 1759 return fuse_notify_poll(fc, size, cs); 1760 1761 case FUSE_NOTIFY_INVAL_INODE: 1762 return fuse_notify_inval_inode(fc, size, cs); 1763 1764 case FUSE_NOTIFY_INVAL_ENTRY: 1765 return fuse_notify_inval_entry(fc, size, cs); 1766 1767 case FUSE_NOTIFY_STORE: 1768 return fuse_notify_store(fc, size, cs); 1769 1770 case FUSE_NOTIFY_RETRIEVE: 1771 return fuse_notify_retrieve(fc, size, cs); 1772 1773 case FUSE_NOTIFY_DELETE: 1774 return fuse_notify_delete(fc, size, cs); 1775 1776 default: 1777 fuse_copy_finish(cs); 1778 return -EINVAL; 1779 } 1780 } 1781 1782 /* Look up request on processing list by unique ID */ 1783 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1784 { 1785 unsigned int hash = fuse_req_hash(unique); 1786 struct fuse_req *req; 1787 1788 list_for_each_entry(req, &fpq->processing[hash], list) { 1789 if (req->in.h.unique == unique) 1790 return req; 1791 } 1792 return NULL; 1793 } 1794 1795 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, 1796 unsigned nbytes) 1797 { 1798 unsigned reqsize = sizeof(struct fuse_out_header); 1799 1800 reqsize += fuse_len_args(args->out_numargs, args->out_args); 1801 1802 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar)) 1803 return -EINVAL; 1804 else if (reqsize > nbytes) { 1805 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1]; 1806 unsigned diffsize = reqsize - nbytes; 1807 1808 if (diffsize > lastarg->size) 1809 return -EINVAL; 1810 lastarg->size -= diffsize; 1811 } 1812 return fuse_copy_args(cs, args->out_numargs, args->out_pages, 1813 args->out_args, args->page_zeroing); 1814 } 1815 1816 /* 1817 * Write a single reply to a request. First the header is copied from 1818 * the write buffer. The request is then searched on the processing 1819 * list by the unique ID found in the header. If found, then remove 1820 * it from the list and copy the rest of the buffer to the request. 1821 * The request is finished by calling fuse_request_end(). 1822 */ 1823 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1824 struct fuse_copy_state *cs, size_t nbytes) 1825 { 1826 int err; 1827 struct fuse_conn *fc = fud->fc; 1828 struct fuse_pqueue *fpq = &fud->pq; 1829 struct fuse_req *req; 1830 struct fuse_out_header oh; 1831 1832 err = -EINVAL; 1833 if (nbytes < sizeof(struct fuse_out_header)) 1834 goto out; 1835 1836 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1837 if (err) 1838 goto copy_finish; 1839 1840 err = -EINVAL; 1841 if (oh.len != nbytes) 1842 goto copy_finish; 1843 1844 /* 1845 * Zero oh.unique indicates unsolicited notification message 1846 * and error contains notification code. 1847 */ 1848 if (!oh.unique) { 1849 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1850 goto out; 1851 } 1852 1853 err = -EINVAL; 1854 if (oh.error <= -1000 || oh.error > 0) 1855 goto copy_finish; 1856 1857 spin_lock(&fpq->lock); 1858 req = NULL; 1859 if (fpq->connected) 1860 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT); 1861 1862 err = -ENOENT; 1863 if (!req) { 1864 spin_unlock(&fpq->lock); 1865 goto copy_finish; 1866 } 1867 1868 /* Is it an interrupt reply ID? */ 1869 if (oh.unique & FUSE_INT_REQ_BIT) { 1870 __fuse_get_request(req); 1871 spin_unlock(&fpq->lock); 1872 1873 err = 0; 1874 if (nbytes != sizeof(struct fuse_out_header)) 1875 err = -EINVAL; 1876 else if (oh.error == -ENOSYS) 1877 fc->no_interrupt = 1; 1878 else if (oh.error == -EAGAIN) 1879 err = queue_interrupt(&fc->iq, req); 1880 1881 fuse_put_request(fc, req); 1882 1883 goto copy_finish; 1884 } 1885 1886 clear_bit(FR_SENT, &req->flags); 1887 list_move(&req->list, &fpq->io); 1888 req->out.h = oh; 1889 set_bit(FR_LOCKED, &req->flags); 1890 spin_unlock(&fpq->lock); 1891 cs->req = req; 1892 if (!req->args->page_replace) 1893 cs->move_pages = 0; 1894 1895 if (oh.error) 1896 err = nbytes != sizeof(oh) ? -EINVAL : 0; 1897 else 1898 err = copy_out_args(cs, req->args, nbytes); 1899 fuse_copy_finish(cs); 1900 1901 spin_lock(&fpq->lock); 1902 clear_bit(FR_LOCKED, &req->flags); 1903 if (!fpq->connected) 1904 err = -ENOENT; 1905 else if (err) 1906 req->out.h.error = -EIO; 1907 if (!test_bit(FR_PRIVATE, &req->flags)) 1908 list_del_init(&req->list); 1909 spin_unlock(&fpq->lock); 1910 1911 fuse_request_end(fc, req); 1912 out: 1913 return err ? err : nbytes; 1914 1915 copy_finish: 1916 fuse_copy_finish(cs); 1917 goto out; 1918 } 1919 1920 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1921 { 1922 struct fuse_copy_state cs; 1923 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1924 1925 if (!fud) 1926 return -EPERM; 1927 1928 if (!iter_is_iovec(from)) 1929 return -EINVAL; 1930 1931 fuse_copy_init(&cs, 0, from); 1932 1933 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1934 } 1935 1936 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1937 struct file *out, loff_t *ppos, 1938 size_t len, unsigned int flags) 1939 { 1940 unsigned int head, tail, mask, count; 1941 unsigned nbuf; 1942 unsigned idx; 1943 struct pipe_buffer *bufs; 1944 struct fuse_copy_state cs; 1945 struct fuse_dev *fud; 1946 size_t rem; 1947 ssize_t ret; 1948 1949 fud = fuse_get_dev(out); 1950 if (!fud) 1951 return -EPERM; 1952 1953 pipe_lock(pipe); 1954 1955 head = pipe->head; 1956 tail = pipe->tail; 1957 mask = pipe->ring_size - 1; 1958 count = head - tail; 1959 1960 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL); 1961 if (!bufs) { 1962 pipe_unlock(pipe); 1963 return -ENOMEM; 1964 } 1965 1966 nbuf = 0; 1967 rem = 0; 1968 for (idx = tail; idx != head && rem < len; idx++) 1969 rem += pipe->bufs[idx & mask].len; 1970 1971 ret = -EINVAL; 1972 if (rem < len) 1973 goto out_free; 1974 1975 rem = len; 1976 while (rem) { 1977 struct pipe_buffer *ibuf; 1978 struct pipe_buffer *obuf; 1979 1980 BUG_ON(nbuf >= pipe->ring_size); 1981 BUG_ON(tail == head); 1982 ibuf = &pipe->bufs[tail & mask]; 1983 obuf = &bufs[nbuf]; 1984 1985 if (rem >= ibuf->len) { 1986 *obuf = *ibuf; 1987 ibuf->ops = NULL; 1988 tail++; 1989 pipe->tail = tail; 1990 } else { 1991 if (!pipe_buf_get(pipe, ibuf)) 1992 goto out_free; 1993 1994 *obuf = *ibuf; 1995 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1996 obuf->len = rem; 1997 ibuf->offset += obuf->len; 1998 ibuf->len -= obuf->len; 1999 } 2000 nbuf++; 2001 rem -= obuf->len; 2002 } 2003 pipe_unlock(pipe); 2004 2005 fuse_copy_init(&cs, 0, NULL); 2006 cs.pipebufs = bufs; 2007 cs.nr_segs = nbuf; 2008 cs.pipe = pipe; 2009 2010 if (flags & SPLICE_F_MOVE) 2011 cs.move_pages = 1; 2012 2013 ret = fuse_dev_do_write(fud, &cs, len); 2014 2015 pipe_lock(pipe); 2016 out_free: 2017 for (idx = 0; idx < nbuf; idx++) 2018 pipe_buf_release(pipe, &bufs[idx]); 2019 pipe_unlock(pipe); 2020 2021 kvfree(bufs); 2022 return ret; 2023 } 2024 2025 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait) 2026 { 2027 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 2028 struct fuse_iqueue *fiq; 2029 struct fuse_dev *fud = fuse_get_dev(file); 2030 2031 if (!fud) 2032 return EPOLLERR; 2033 2034 fiq = &fud->fc->iq; 2035 poll_wait(file, &fiq->waitq, wait); 2036 2037 spin_lock(&fiq->lock); 2038 if (!fiq->connected) 2039 mask = EPOLLERR; 2040 else if (request_pending(fiq)) 2041 mask |= EPOLLIN | EPOLLRDNORM; 2042 spin_unlock(&fiq->lock); 2043 2044 return mask; 2045 } 2046 2047 /* Abort all requests on the given list (pending or processing) */ 2048 static void end_requests(struct fuse_conn *fc, struct list_head *head) 2049 { 2050 while (!list_empty(head)) { 2051 struct fuse_req *req; 2052 req = list_entry(head->next, struct fuse_req, list); 2053 req->out.h.error = -ECONNABORTED; 2054 clear_bit(FR_SENT, &req->flags); 2055 list_del_init(&req->list); 2056 fuse_request_end(fc, req); 2057 } 2058 } 2059 2060 static void end_polls(struct fuse_conn *fc) 2061 { 2062 struct rb_node *p; 2063 2064 p = rb_first(&fc->polled_files); 2065 2066 while (p) { 2067 struct fuse_file *ff; 2068 ff = rb_entry(p, struct fuse_file, polled_node); 2069 wake_up_interruptible_all(&ff->poll_wait); 2070 2071 p = rb_next(p); 2072 } 2073 } 2074 2075 /* 2076 * Abort all requests. 2077 * 2078 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2079 * filesystem. 2080 * 2081 * The same effect is usually achievable through killing the filesystem daemon 2082 * and all users of the filesystem. The exception is the combination of an 2083 * asynchronous request and the tricky deadlock (see 2084 * Documentation/filesystems/fuse.txt). 2085 * 2086 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2087 * requests, they should be finished off immediately. Locked requests will be 2088 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2089 * requests. It is possible that some request will finish before we can. This 2090 * is OK, the request will in that case be removed from the list before we touch 2091 * it. 2092 */ 2093 void fuse_abort_conn(struct fuse_conn *fc) 2094 { 2095 struct fuse_iqueue *fiq = &fc->iq; 2096 2097 spin_lock(&fc->lock); 2098 if (fc->connected) { 2099 struct fuse_dev *fud; 2100 struct fuse_req *req, *next; 2101 LIST_HEAD(to_end); 2102 unsigned int i; 2103 2104 /* Background queuing checks fc->connected under bg_lock */ 2105 spin_lock(&fc->bg_lock); 2106 fc->connected = 0; 2107 spin_unlock(&fc->bg_lock); 2108 2109 fuse_set_initialized(fc); 2110 list_for_each_entry(fud, &fc->devices, entry) { 2111 struct fuse_pqueue *fpq = &fud->pq; 2112 2113 spin_lock(&fpq->lock); 2114 fpq->connected = 0; 2115 list_for_each_entry_safe(req, next, &fpq->io, list) { 2116 req->out.h.error = -ECONNABORTED; 2117 spin_lock(&req->waitq.lock); 2118 set_bit(FR_ABORTED, &req->flags); 2119 if (!test_bit(FR_LOCKED, &req->flags)) { 2120 set_bit(FR_PRIVATE, &req->flags); 2121 __fuse_get_request(req); 2122 list_move(&req->list, &to_end); 2123 } 2124 spin_unlock(&req->waitq.lock); 2125 } 2126 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2127 list_splice_tail_init(&fpq->processing[i], 2128 &to_end); 2129 spin_unlock(&fpq->lock); 2130 } 2131 spin_lock(&fc->bg_lock); 2132 fc->blocked = 0; 2133 fc->max_background = UINT_MAX; 2134 flush_bg_queue(fc); 2135 spin_unlock(&fc->bg_lock); 2136 2137 spin_lock(&fiq->lock); 2138 fiq->connected = 0; 2139 list_for_each_entry(req, &fiq->pending, list) 2140 clear_bit(FR_PENDING, &req->flags); 2141 list_splice_tail_init(&fiq->pending, &to_end); 2142 while (forget_pending(fiq)) 2143 kfree(fuse_dequeue_forget(fiq, 1, NULL)); 2144 wake_up_all(&fiq->waitq); 2145 spin_unlock(&fiq->lock); 2146 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2147 end_polls(fc); 2148 wake_up_all(&fc->blocked_waitq); 2149 spin_unlock(&fc->lock); 2150 2151 end_requests(fc, &to_end); 2152 } else { 2153 spin_unlock(&fc->lock); 2154 } 2155 } 2156 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2157 2158 void fuse_wait_aborted(struct fuse_conn *fc) 2159 { 2160 /* matches implicit memory barrier in fuse_drop_waiting() */ 2161 smp_mb(); 2162 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0); 2163 } 2164 2165 int fuse_dev_release(struct inode *inode, struct file *file) 2166 { 2167 struct fuse_dev *fud = fuse_get_dev(file); 2168 2169 if (fud) { 2170 struct fuse_conn *fc = fud->fc; 2171 struct fuse_pqueue *fpq = &fud->pq; 2172 LIST_HEAD(to_end); 2173 unsigned int i; 2174 2175 spin_lock(&fpq->lock); 2176 WARN_ON(!list_empty(&fpq->io)); 2177 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2178 list_splice_init(&fpq->processing[i], &to_end); 2179 spin_unlock(&fpq->lock); 2180 2181 end_requests(fc, &to_end); 2182 2183 /* Are we the last open device? */ 2184 if (atomic_dec_and_test(&fc->dev_count)) { 2185 WARN_ON(fc->iq.fasync != NULL); 2186 fuse_abort_conn(fc); 2187 } 2188 fuse_dev_free(fud); 2189 } 2190 return 0; 2191 } 2192 EXPORT_SYMBOL_GPL(fuse_dev_release); 2193 2194 static int fuse_dev_fasync(int fd, struct file *file, int on) 2195 { 2196 struct fuse_dev *fud = fuse_get_dev(file); 2197 2198 if (!fud) 2199 return -EPERM; 2200 2201 /* No locking - fasync_helper does its own locking */ 2202 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2203 } 2204 2205 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2206 { 2207 struct fuse_dev *fud; 2208 2209 if (new->private_data) 2210 return -EINVAL; 2211 2212 fud = fuse_dev_alloc_install(fc); 2213 if (!fud) 2214 return -ENOMEM; 2215 2216 new->private_data = fud; 2217 atomic_inc(&fc->dev_count); 2218 2219 return 0; 2220 } 2221 2222 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2223 unsigned long arg) 2224 { 2225 int err = -ENOTTY; 2226 2227 if (cmd == FUSE_DEV_IOC_CLONE) { 2228 int oldfd; 2229 2230 err = -EFAULT; 2231 if (!get_user(oldfd, (__u32 __user *) arg)) { 2232 struct file *old = fget(oldfd); 2233 2234 err = -EINVAL; 2235 if (old) { 2236 struct fuse_dev *fud = NULL; 2237 2238 /* 2239 * Check against file->f_op because CUSE 2240 * uses the same ioctl handler. 2241 */ 2242 if (old->f_op == file->f_op && 2243 old->f_cred->user_ns == file->f_cred->user_ns) 2244 fud = fuse_get_dev(old); 2245 2246 if (fud) { 2247 mutex_lock(&fuse_mutex); 2248 err = fuse_device_clone(fud->fc, file); 2249 mutex_unlock(&fuse_mutex); 2250 } 2251 fput(old); 2252 } 2253 } 2254 } 2255 return err; 2256 } 2257 2258 const struct file_operations fuse_dev_operations = { 2259 .owner = THIS_MODULE, 2260 .open = fuse_dev_open, 2261 .llseek = no_llseek, 2262 .read_iter = fuse_dev_read, 2263 .splice_read = fuse_dev_splice_read, 2264 .write_iter = fuse_dev_write, 2265 .splice_write = fuse_dev_splice_write, 2266 .poll = fuse_dev_poll, 2267 .release = fuse_dev_release, 2268 .fasync = fuse_dev_fasync, 2269 .unlocked_ioctl = fuse_dev_ioctl, 2270 .compat_ioctl = compat_ptr_ioctl, 2271 }; 2272 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2273 2274 static struct miscdevice fuse_miscdevice = { 2275 .minor = FUSE_MINOR, 2276 .name = "fuse", 2277 .fops = &fuse_dev_operations, 2278 }; 2279 2280 int __init fuse_dev_init(void) 2281 { 2282 int err = -ENOMEM; 2283 fuse_req_cachep = kmem_cache_create("fuse_request", 2284 sizeof(struct fuse_req), 2285 0, 0, NULL); 2286 if (!fuse_req_cachep) 2287 goto out; 2288 2289 err = misc_register(&fuse_miscdevice); 2290 if (err) 2291 goto out_cache_clean; 2292 2293 return 0; 2294 2295 out_cache_clean: 2296 kmem_cache_destroy(fuse_req_cachep); 2297 out: 2298 return err; 2299 } 2300 2301 void fuse_dev_cleanup(void) 2302 { 2303 misc_deregister(&fuse_miscdevice); 2304 kmem_cache_destroy(fuse_req_cachep); 2305 } 2306