1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/poll.h> 14 #include <linux/sched/signal.h> 15 #include <linux/uio.h> 16 #include <linux/miscdevice.h> 17 #include <linux/pagemap.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/pipe_fs_i.h> 21 #include <linux/swap.h> 22 #include <linux/splice.h> 23 #include <linux/sched.h> 24 25 MODULE_ALIAS_MISCDEV(FUSE_MINOR); 26 MODULE_ALIAS("devname:fuse"); 27 28 /* Ordinary requests have even IDs, while interrupts IDs are odd */ 29 #define FUSE_INT_REQ_BIT (1ULL << 0) 30 #define FUSE_REQ_ID_STEP (1ULL << 1) 31 32 static struct kmem_cache *fuse_req_cachep; 33 34 static struct fuse_dev *fuse_get_dev(struct file *file) 35 { 36 /* 37 * Lockless access is OK, because file->private data is set 38 * once during mount and is valid until the file is released. 39 */ 40 return READ_ONCE(file->private_data); 41 } 42 43 static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req) 44 { 45 INIT_LIST_HEAD(&req->list); 46 INIT_LIST_HEAD(&req->intr_entry); 47 init_waitqueue_head(&req->waitq); 48 refcount_set(&req->count, 1); 49 __set_bit(FR_PENDING, &req->flags); 50 req->fm = fm; 51 } 52 53 static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags) 54 { 55 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags); 56 if (req) 57 fuse_request_init(fm, req); 58 59 return req; 60 } 61 62 static void fuse_request_free(struct fuse_req *req) 63 { 64 kmem_cache_free(fuse_req_cachep, req); 65 } 66 67 static void __fuse_get_request(struct fuse_req *req) 68 { 69 refcount_inc(&req->count); 70 } 71 72 /* Must be called with > 1 refcount */ 73 static void __fuse_put_request(struct fuse_req *req) 74 { 75 refcount_dec(&req->count); 76 } 77 78 void fuse_set_initialized(struct fuse_conn *fc) 79 { 80 /* Make sure stores before this are seen on another CPU */ 81 smp_wmb(); 82 fc->initialized = 1; 83 } 84 85 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 86 { 87 return !fc->initialized || (for_background && fc->blocked); 88 } 89 90 static void fuse_drop_waiting(struct fuse_conn *fc) 91 { 92 /* 93 * lockess check of fc->connected is okay, because atomic_dec_and_test() 94 * provides a memory barrier matched with the one in fuse_wait_aborted() 95 * to ensure no wake-up is missed. 96 */ 97 if (atomic_dec_and_test(&fc->num_waiting) && 98 !READ_ONCE(fc->connected)) { 99 /* wake up aborters */ 100 wake_up_all(&fc->blocked_waitq); 101 } 102 } 103 104 static void fuse_put_request(struct fuse_req *req); 105 106 static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background) 107 { 108 struct fuse_conn *fc = fm->fc; 109 struct fuse_req *req; 110 int err; 111 atomic_inc(&fc->num_waiting); 112 113 if (fuse_block_alloc(fc, for_background)) { 114 err = -EINTR; 115 if (wait_event_killable_exclusive(fc->blocked_waitq, 116 !fuse_block_alloc(fc, for_background))) 117 goto out; 118 } 119 /* Matches smp_wmb() in fuse_set_initialized() */ 120 smp_rmb(); 121 122 err = -ENOTCONN; 123 if (!fc->connected) 124 goto out; 125 126 err = -ECONNREFUSED; 127 if (fc->conn_error) 128 goto out; 129 130 req = fuse_request_alloc(fm, GFP_KERNEL); 131 err = -ENOMEM; 132 if (!req) { 133 if (for_background) 134 wake_up(&fc->blocked_waitq); 135 goto out; 136 } 137 138 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid()); 139 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid()); 140 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 141 142 __set_bit(FR_WAITING, &req->flags); 143 if (for_background) 144 __set_bit(FR_BACKGROUND, &req->flags); 145 146 if (unlikely(req->in.h.uid == ((uid_t)-1) || 147 req->in.h.gid == ((gid_t)-1))) { 148 fuse_put_request(req); 149 return ERR_PTR(-EOVERFLOW); 150 } 151 return req; 152 153 out: 154 fuse_drop_waiting(fc); 155 return ERR_PTR(err); 156 } 157 158 static void fuse_put_request(struct fuse_req *req) 159 { 160 struct fuse_conn *fc = req->fm->fc; 161 162 if (refcount_dec_and_test(&req->count)) { 163 if (test_bit(FR_BACKGROUND, &req->flags)) { 164 /* 165 * We get here in the unlikely case that a background 166 * request was allocated but not sent 167 */ 168 spin_lock(&fc->bg_lock); 169 if (!fc->blocked) 170 wake_up(&fc->blocked_waitq); 171 spin_unlock(&fc->bg_lock); 172 } 173 174 if (test_bit(FR_WAITING, &req->flags)) { 175 __clear_bit(FR_WAITING, &req->flags); 176 fuse_drop_waiting(fc); 177 } 178 179 fuse_request_free(req); 180 } 181 } 182 183 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args) 184 { 185 unsigned nbytes = 0; 186 unsigned i; 187 188 for (i = 0; i < numargs; i++) 189 nbytes += args[i].size; 190 191 return nbytes; 192 } 193 EXPORT_SYMBOL_GPL(fuse_len_args); 194 195 u64 fuse_get_unique(struct fuse_iqueue *fiq) 196 { 197 fiq->reqctr += FUSE_REQ_ID_STEP; 198 return fiq->reqctr; 199 } 200 EXPORT_SYMBOL_GPL(fuse_get_unique); 201 202 static unsigned int fuse_req_hash(u64 unique) 203 { 204 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS); 205 } 206 207 /** 208 * A new request is available, wake fiq->waitq 209 */ 210 static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq) 211 __releases(fiq->lock) 212 { 213 wake_up(&fiq->waitq); 214 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 215 spin_unlock(&fiq->lock); 216 } 217 218 const struct fuse_iqueue_ops fuse_dev_fiq_ops = { 219 .wake_forget_and_unlock = fuse_dev_wake_and_unlock, 220 .wake_interrupt_and_unlock = fuse_dev_wake_and_unlock, 221 .wake_pending_and_unlock = fuse_dev_wake_and_unlock, 222 }; 223 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops); 224 225 static void queue_request_and_unlock(struct fuse_iqueue *fiq, 226 struct fuse_req *req) 227 __releases(fiq->lock) 228 { 229 req->in.h.len = sizeof(struct fuse_in_header) + 230 fuse_len_args(req->args->in_numargs, 231 (struct fuse_arg *) req->args->in_args); 232 list_add_tail(&req->list, &fiq->pending); 233 fiq->ops->wake_pending_and_unlock(fiq); 234 } 235 236 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 237 u64 nodeid, u64 nlookup) 238 { 239 struct fuse_iqueue *fiq = &fc->iq; 240 241 forget->forget_one.nodeid = nodeid; 242 forget->forget_one.nlookup = nlookup; 243 244 spin_lock(&fiq->lock); 245 if (fiq->connected) { 246 fiq->forget_list_tail->next = forget; 247 fiq->forget_list_tail = forget; 248 fiq->ops->wake_forget_and_unlock(fiq); 249 } else { 250 kfree(forget); 251 spin_unlock(&fiq->lock); 252 } 253 } 254 255 static void flush_bg_queue(struct fuse_conn *fc) 256 { 257 struct fuse_iqueue *fiq = &fc->iq; 258 259 while (fc->active_background < fc->max_background && 260 !list_empty(&fc->bg_queue)) { 261 struct fuse_req *req; 262 263 req = list_first_entry(&fc->bg_queue, struct fuse_req, list); 264 list_del(&req->list); 265 fc->active_background++; 266 spin_lock(&fiq->lock); 267 req->in.h.unique = fuse_get_unique(fiq); 268 queue_request_and_unlock(fiq, req); 269 } 270 } 271 272 /* 273 * This function is called when a request is finished. Either a reply 274 * has arrived or it was aborted (and not yet sent) or some error 275 * occurred during communication with userspace, or the device file 276 * was closed. The requester thread is woken up (if still waiting), 277 * the 'end' callback is called if given, else the reference to the 278 * request is released 279 */ 280 void fuse_request_end(struct fuse_req *req) 281 { 282 struct fuse_mount *fm = req->fm; 283 struct fuse_conn *fc = fm->fc; 284 struct fuse_iqueue *fiq = &fc->iq; 285 286 if (test_and_set_bit(FR_FINISHED, &req->flags)) 287 goto put_request; 288 289 /* 290 * test_and_set_bit() implies smp_mb() between bit 291 * changing and below FR_INTERRUPTED check. Pairs with 292 * smp_mb() from queue_interrupt(). 293 */ 294 if (test_bit(FR_INTERRUPTED, &req->flags)) { 295 spin_lock(&fiq->lock); 296 list_del_init(&req->intr_entry); 297 spin_unlock(&fiq->lock); 298 } 299 WARN_ON(test_bit(FR_PENDING, &req->flags)); 300 WARN_ON(test_bit(FR_SENT, &req->flags)); 301 if (test_bit(FR_BACKGROUND, &req->flags)) { 302 spin_lock(&fc->bg_lock); 303 clear_bit(FR_BACKGROUND, &req->flags); 304 if (fc->num_background == fc->max_background) { 305 fc->blocked = 0; 306 wake_up(&fc->blocked_waitq); 307 } else if (!fc->blocked) { 308 /* 309 * Wake up next waiter, if any. It's okay to use 310 * waitqueue_active(), as we've already synced up 311 * fc->blocked with waiters with the wake_up() call 312 * above. 313 */ 314 if (waitqueue_active(&fc->blocked_waitq)) 315 wake_up(&fc->blocked_waitq); 316 } 317 318 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_local_page(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_local(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_workingset | 787 1 << PG_reclaim | 788 1 << PG_waiters))) { 789 dump_page(page, "fuse: trying to steal weird page"); 790 return 1; 791 } 792 return 0; 793 } 794 795 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 796 { 797 int err; 798 struct page *oldpage = *pagep; 799 struct page *newpage; 800 struct pipe_buffer *buf = cs->pipebufs; 801 802 get_page(oldpage); 803 err = unlock_request(cs->req); 804 if (err) 805 goto out_put_old; 806 807 fuse_copy_finish(cs); 808 809 err = pipe_buf_confirm(cs->pipe, buf); 810 if (err) 811 goto out_put_old; 812 813 BUG_ON(!cs->nr_segs); 814 cs->currbuf = buf; 815 cs->len = buf->len; 816 cs->pipebufs++; 817 cs->nr_segs--; 818 819 if (cs->len != PAGE_SIZE) 820 goto out_fallback; 821 822 if (!pipe_buf_try_steal(cs->pipe, buf)) 823 goto out_fallback; 824 825 newpage = buf->page; 826 827 if (!PageUptodate(newpage)) 828 SetPageUptodate(newpage); 829 830 ClearPageMappedToDisk(newpage); 831 832 if (fuse_check_page(newpage) != 0) 833 goto out_fallback_unlock; 834 835 /* 836 * This is a new and locked page, it shouldn't be mapped or 837 * have any special flags on it 838 */ 839 if (WARN_ON(page_mapped(oldpage))) 840 goto out_fallback_unlock; 841 if (WARN_ON(page_has_private(oldpage))) 842 goto out_fallback_unlock; 843 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 844 goto out_fallback_unlock; 845 if (WARN_ON(PageMlocked(oldpage))) 846 goto out_fallback_unlock; 847 848 replace_page_cache_page(oldpage, newpage); 849 850 get_page(newpage); 851 852 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 853 lru_cache_add(newpage); 854 855 /* 856 * Release while we have extra ref on stolen page. Otherwise 857 * anon_pipe_buf_release() might think the page can be reused. 858 */ 859 pipe_buf_release(cs->pipe, buf); 860 861 err = 0; 862 spin_lock(&cs->req->waitq.lock); 863 if (test_bit(FR_ABORTED, &cs->req->flags)) 864 err = -ENOENT; 865 else 866 *pagep = newpage; 867 spin_unlock(&cs->req->waitq.lock); 868 869 if (err) { 870 unlock_page(newpage); 871 put_page(newpage); 872 goto out_put_old; 873 } 874 875 unlock_page(oldpage); 876 /* Drop ref for ap->pages[] array */ 877 put_page(oldpage); 878 cs->len = 0; 879 880 err = 0; 881 out_put_old: 882 /* Drop ref obtained in this function */ 883 put_page(oldpage); 884 return err; 885 886 out_fallback_unlock: 887 unlock_page(newpage); 888 out_fallback: 889 cs->pg = buf->page; 890 cs->offset = buf->offset; 891 892 err = lock_request(cs->req); 893 if (!err) 894 err = 1; 895 896 goto out_put_old; 897 } 898 899 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 900 unsigned offset, unsigned count) 901 { 902 struct pipe_buffer *buf; 903 int err; 904 905 if (cs->nr_segs >= cs->pipe->max_usage) 906 return -EIO; 907 908 get_page(page); 909 err = unlock_request(cs->req); 910 if (err) { 911 put_page(page); 912 return err; 913 } 914 915 fuse_copy_finish(cs); 916 917 buf = cs->pipebufs; 918 buf->page = page; 919 buf->offset = offset; 920 buf->len = count; 921 922 cs->pipebufs++; 923 cs->nr_segs++; 924 cs->len = 0; 925 926 return 0; 927 } 928 929 /* 930 * Copy a page in the request to/from the userspace buffer. Must be 931 * done atomically 932 */ 933 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 934 unsigned offset, unsigned count, int zeroing) 935 { 936 int err; 937 struct page *page = *pagep; 938 939 if (page && zeroing && count < PAGE_SIZE) 940 clear_highpage(page); 941 942 while (count) { 943 if (cs->write && cs->pipebufs && page) { 944 return fuse_ref_page(cs, page, offset, count); 945 } else if (!cs->len) { 946 if (cs->move_pages && page && 947 offset == 0 && count == PAGE_SIZE) { 948 err = fuse_try_move_page(cs, pagep); 949 if (err <= 0) 950 return err; 951 } else { 952 err = fuse_copy_fill(cs); 953 if (err) 954 return err; 955 } 956 } 957 if (page) { 958 void *mapaddr = kmap_local_page(page); 959 void *buf = mapaddr + offset; 960 offset += fuse_copy_do(cs, &buf, &count); 961 kunmap_local(mapaddr); 962 } else 963 offset += fuse_copy_do(cs, NULL, &count); 964 } 965 if (page && !cs->write) 966 flush_dcache_page(page); 967 return 0; 968 } 969 970 /* Copy pages in the request to/from userspace buffer */ 971 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 972 int zeroing) 973 { 974 unsigned i; 975 struct fuse_req *req = cs->req; 976 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args); 977 978 979 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) { 980 int err; 981 unsigned int offset = ap->descs[i].offset; 982 unsigned int count = min(nbytes, ap->descs[i].length); 983 984 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing); 985 if (err) 986 return err; 987 988 nbytes -= count; 989 } 990 return 0; 991 } 992 993 /* Copy a single argument in the request to/from userspace buffer */ 994 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 995 { 996 while (size) { 997 if (!cs->len) { 998 int err = fuse_copy_fill(cs); 999 if (err) 1000 return err; 1001 } 1002 fuse_copy_do(cs, &val, &size); 1003 } 1004 return 0; 1005 } 1006 1007 /* Copy request arguments to/from userspace buffer */ 1008 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1009 unsigned argpages, struct fuse_arg *args, 1010 int zeroing) 1011 { 1012 int err = 0; 1013 unsigned i; 1014 1015 for (i = 0; !err && i < numargs; i++) { 1016 struct fuse_arg *arg = &args[i]; 1017 if (i == numargs - 1 && argpages) 1018 err = fuse_copy_pages(cs, arg->size, zeroing); 1019 else 1020 err = fuse_copy_one(cs, arg->value, arg->size); 1021 } 1022 return err; 1023 } 1024 1025 static int forget_pending(struct fuse_iqueue *fiq) 1026 { 1027 return fiq->forget_list_head.next != NULL; 1028 } 1029 1030 static int request_pending(struct fuse_iqueue *fiq) 1031 { 1032 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1033 forget_pending(fiq); 1034 } 1035 1036 /* 1037 * Transfer an interrupt request to userspace 1038 * 1039 * Unlike other requests this is assembled on demand, without a need 1040 * to allocate a separate fuse_req structure. 1041 * 1042 * Called with fiq->lock held, releases it 1043 */ 1044 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1045 struct fuse_copy_state *cs, 1046 size_t nbytes, struct fuse_req *req) 1047 __releases(fiq->lock) 1048 { 1049 struct fuse_in_header ih; 1050 struct fuse_interrupt_in arg; 1051 unsigned reqsize = sizeof(ih) + sizeof(arg); 1052 int err; 1053 1054 list_del_init(&req->intr_entry); 1055 memset(&ih, 0, sizeof(ih)); 1056 memset(&arg, 0, sizeof(arg)); 1057 ih.len = reqsize; 1058 ih.opcode = FUSE_INTERRUPT; 1059 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT); 1060 arg.unique = req->in.h.unique; 1061 1062 spin_unlock(&fiq->lock); 1063 if (nbytes < reqsize) 1064 return -EINVAL; 1065 1066 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1067 if (!err) 1068 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1069 fuse_copy_finish(cs); 1070 1071 return err ? err : reqsize; 1072 } 1073 1074 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq, 1075 unsigned int max, 1076 unsigned int *countp) 1077 { 1078 struct fuse_forget_link *head = fiq->forget_list_head.next; 1079 struct fuse_forget_link **newhead = &head; 1080 unsigned count; 1081 1082 for (count = 0; *newhead != NULL && count < max; count++) 1083 newhead = &(*newhead)->next; 1084 1085 fiq->forget_list_head.next = *newhead; 1086 *newhead = NULL; 1087 if (fiq->forget_list_head.next == NULL) 1088 fiq->forget_list_tail = &fiq->forget_list_head; 1089 1090 if (countp != NULL) 1091 *countp = count; 1092 1093 return head; 1094 } 1095 EXPORT_SYMBOL(fuse_dequeue_forget); 1096 1097 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1098 struct fuse_copy_state *cs, 1099 size_t nbytes) 1100 __releases(fiq->lock) 1101 { 1102 int err; 1103 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL); 1104 struct fuse_forget_in arg = { 1105 .nlookup = forget->forget_one.nlookup, 1106 }; 1107 struct fuse_in_header ih = { 1108 .opcode = FUSE_FORGET, 1109 .nodeid = forget->forget_one.nodeid, 1110 .unique = fuse_get_unique(fiq), 1111 .len = sizeof(ih) + sizeof(arg), 1112 }; 1113 1114 spin_unlock(&fiq->lock); 1115 kfree(forget); 1116 if (nbytes < ih.len) 1117 return -EINVAL; 1118 1119 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1120 if (!err) 1121 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1122 fuse_copy_finish(cs); 1123 1124 if (err) 1125 return err; 1126 1127 return ih.len; 1128 } 1129 1130 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1131 struct fuse_copy_state *cs, size_t nbytes) 1132 __releases(fiq->lock) 1133 { 1134 int err; 1135 unsigned max_forgets; 1136 unsigned count; 1137 struct fuse_forget_link *head; 1138 struct fuse_batch_forget_in arg = { .count = 0 }; 1139 struct fuse_in_header ih = { 1140 .opcode = FUSE_BATCH_FORGET, 1141 .unique = fuse_get_unique(fiq), 1142 .len = sizeof(ih) + sizeof(arg), 1143 }; 1144 1145 if (nbytes < ih.len) { 1146 spin_unlock(&fiq->lock); 1147 return -EINVAL; 1148 } 1149 1150 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1151 head = fuse_dequeue_forget(fiq, max_forgets, &count); 1152 spin_unlock(&fiq->lock); 1153 1154 arg.count = count; 1155 ih.len += count * sizeof(struct fuse_forget_one); 1156 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1157 if (!err) 1158 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1159 1160 while (head) { 1161 struct fuse_forget_link *forget = head; 1162 1163 if (!err) { 1164 err = fuse_copy_one(cs, &forget->forget_one, 1165 sizeof(forget->forget_one)); 1166 } 1167 head = forget->next; 1168 kfree(forget); 1169 } 1170 1171 fuse_copy_finish(cs); 1172 1173 if (err) 1174 return err; 1175 1176 return ih.len; 1177 } 1178 1179 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1180 struct fuse_copy_state *cs, 1181 size_t nbytes) 1182 __releases(fiq->lock) 1183 { 1184 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1185 return fuse_read_single_forget(fiq, cs, nbytes); 1186 else 1187 return fuse_read_batch_forget(fiq, cs, nbytes); 1188 } 1189 1190 /* 1191 * Read a single request into the userspace filesystem's buffer. This 1192 * function waits until a request is available, then removes it from 1193 * the pending list and copies request data to userspace buffer. If 1194 * no reply is needed (FORGET) or request has been aborted or there 1195 * was an error during the copying then it's finished by calling 1196 * fuse_request_end(). Otherwise add it to the processing list, and set 1197 * the 'sent' flag. 1198 */ 1199 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1200 struct fuse_copy_state *cs, size_t nbytes) 1201 { 1202 ssize_t err; 1203 struct fuse_conn *fc = fud->fc; 1204 struct fuse_iqueue *fiq = &fc->iq; 1205 struct fuse_pqueue *fpq = &fud->pq; 1206 struct fuse_req *req; 1207 struct fuse_args *args; 1208 unsigned reqsize; 1209 unsigned int hash; 1210 1211 /* 1212 * Require sane minimum read buffer - that has capacity for fixed part 1213 * of any request header + negotiated max_write room for data. 1214 * 1215 * Historically libfuse reserves 4K for fixed header room, but e.g. 1216 * GlusterFS reserves only 80 bytes 1217 * 1218 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)` 1219 * 1220 * which is the absolute minimum any sane filesystem should be using 1221 * for header room. 1222 */ 1223 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 1224 sizeof(struct fuse_in_header) + 1225 sizeof(struct fuse_write_in) + 1226 fc->max_write)) 1227 return -EINVAL; 1228 1229 restart: 1230 for (;;) { 1231 spin_lock(&fiq->lock); 1232 if (!fiq->connected || request_pending(fiq)) 1233 break; 1234 spin_unlock(&fiq->lock); 1235 1236 if (file->f_flags & O_NONBLOCK) 1237 return -EAGAIN; 1238 err = wait_event_interruptible_exclusive(fiq->waitq, 1239 !fiq->connected || request_pending(fiq)); 1240 if (err) 1241 return err; 1242 } 1243 1244 if (!fiq->connected) { 1245 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1246 goto err_unlock; 1247 } 1248 1249 if (!list_empty(&fiq->interrupts)) { 1250 req = list_entry(fiq->interrupts.next, struct fuse_req, 1251 intr_entry); 1252 return fuse_read_interrupt(fiq, cs, nbytes, req); 1253 } 1254 1255 if (forget_pending(fiq)) { 1256 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1257 return fuse_read_forget(fc, fiq, cs, nbytes); 1258 1259 if (fiq->forget_batch <= -8) 1260 fiq->forget_batch = 16; 1261 } 1262 1263 req = list_entry(fiq->pending.next, struct fuse_req, list); 1264 clear_bit(FR_PENDING, &req->flags); 1265 list_del_init(&req->list); 1266 spin_unlock(&fiq->lock); 1267 1268 args = req->args; 1269 reqsize = req->in.h.len; 1270 1271 /* If request is too large, reply with an error and restart the read */ 1272 if (nbytes < reqsize) { 1273 req->out.h.error = -EIO; 1274 /* SETXATTR is special, since it may contain too large data */ 1275 if (args->opcode == FUSE_SETXATTR) 1276 req->out.h.error = -E2BIG; 1277 fuse_request_end(req); 1278 goto restart; 1279 } 1280 spin_lock(&fpq->lock); 1281 /* 1282 * Must not put request on fpq->io queue after having been shut down by 1283 * fuse_abort_conn() 1284 */ 1285 if (!fpq->connected) { 1286 req->out.h.error = err = -ECONNABORTED; 1287 goto out_end; 1288 1289 } 1290 list_add(&req->list, &fpq->io); 1291 spin_unlock(&fpq->lock); 1292 cs->req = req; 1293 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h)); 1294 if (!err) 1295 err = fuse_copy_args(cs, args->in_numargs, args->in_pages, 1296 (struct fuse_arg *) args->in_args, 0); 1297 fuse_copy_finish(cs); 1298 spin_lock(&fpq->lock); 1299 clear_bit(FR_LOCKED, &req->flags); 1300 if (!fpq->connected) { 1301 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1302 goto out_end; 1303 } 1304 if (err) { 1305 req->out.h.error = -EIO; 1306 goto out_end; 1307 } 1308 if (!test_bit(FR_ISREPLY, &req->flags)) { 1309 err = reqsize; 1310 goto out_end; 1311 } 1312 hash = fuse_req_hash(req->in.h.unique); 1313 list_move_tail(&req->list, &fpq->processing[hash]); 1314 __fuse_get_request(req); 1315 set_bit(FR_SENT, &req->flags); 1316 spin_unlock(&fpq->lock); 1317 /* matches barrier in request_wait_answer() */ 1318 smp_mb__after_atomic(); 1319 if (test_bit(FR_INTERRUPTED, &req->flags)) 1320 queue_interrupt(req); 1321 fuse_put_request(req); 1322 1323 return reqsize; 1324 1325 out_end: 1326 if (!test_bit(FR_PRIVATE, &req->flags)) 1327 list_del_init(&req->list); 1328 spin_unlock(&fpq->lock); 1329 fuse_request_end(req); 1330 return err; 1331 1332 err_unlock: 1333 spin_unlock(&fiq->lock); 1334 return err; 1335 } 1336 1337 static int fuse_dev_open(struct inode *inode, struct file *file) 1338 { 1339 /* 1340 * The fuse device's file's private_data is used to hold 1341 * the fuse_conn(ection) when it is mounted, and is used to 1342 * keep track of whether the file has been mounted already. 1343 */ 1344 file->private_data = NULL; 1345 return 0; 1346 } 1347 1348 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1349 { 1350 struct fuse_copy_state cs; 1351 struct file *file = iocb->ki_filp; 1352 struct fuse_dev *fud = fuse_get_dev(file); 1353 1354 if (!fud) 1355 return -EPERM; 1356 1357 if (!iter_is_iovec(to)) 1358 return -EINVAL; 1359 1360 fuse_copy_init(&cs, 1, to); 1361 1362 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1363 } 1364 1365 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1366 struct pipe_inode_info *pipe, 1367 size_t len, unsigned int flags) 1368 { 1369 int total, ret; 1370 int page_nr = 0; 1371 struct pipe_buffer *bufs; 1372 struct fuse_copy_state cs; 1373 struct fuse_dev *fud = fuse_get_dev(in); 1374 1375 if (!fud) 1376 return -EPERM; 1377 1378 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer), 1379 GFP_KERNEL); 1380 if (!bufs) 1381 return -ENOMEM; 1382 1383 fuse_copy_init(&cs, 1, NULL); 1384 cs.pipebufs = bufs; 1385 cs.pipe = pipe; 1386 ret = fuse_dev_do_read(fud, in, &cs, len); 1387 if (ret < 0) 1388 goto out; 1389 1390 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) { 1391 ret = -EIO; 1392 goto out; 1393 } 1394 1395 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1396 /* 1397 * Need to be careful about this. Having buf->ops in module 1398 * code can Oops if the buffer persists after module unload. 1399 */ 1400 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1401 bufs[page_nr].flags = 0; 1402 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1403 if (unlikely(ret < 0)) 1404 break; 1405 } 1406 if (total) 1407 ret = total; 1408 out: 1409 for (; page_nr < cs.nr_segs; page_nr++) 1410 put_page(bufs[page_nr].page); 1411 1412 kvfree(bufs); 1413 return ret; 1414 } 1415 1416 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1417 struct fuse_copy_state *cs) 1418 { 1419 struct fuse_notify_poll_wakeup_out outarg; 1420 int err = -EINVAL; 1421 1422 if (size != sizeof(outarg)) 1423 goto err; 1424 1425 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1426 if (err) 1427 goto err; 1428 1429 fuse_copy_finish(cs); 1430 return fuse_notify_poll_wakeup(fc, &outarg); 1431 1432 err: 1433 fuse_copy_finish(cs); 1434 return err; 1435 } 1436 1437 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1438 struct fuse_copy_state *cs) 1439 { 1440 struct fuse_notify_inval_inode_out outarg; 1441 int err = -EINVAL; 1442 1443 if (size != sizeof(outarg)) 1444 goto err; 1445 1446 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1447 if (err) 1448 goto err; 1449 fuse_copy_finish(cs); 1450 1451 down_read(&fc->killsb); 1452 err = fuse_reverse_inval_inode(fc, outarg.ino, 1453 outarg.off, outarg.len); 1454 up_read(&fc->killsb); 1455 return err; 1456 1457 err: 1458 fuse_copy_finish(cs); 1459 return err; 1460 } 1461 1462 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1463 struct fuse_copy_state *cs) 1464 { 1465 struct fuse_notify_inval_entry_out outarg; 1466 int err = -ENOMEM; 1467 char *buf; 1468 struct qstr name; 1469 1470 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1471 if (!buf) 1472 goto err; 1473 1474 err = -EINVAL; 1475 if (size < sizeof(outarg)) 1476 goto err; 1477 1478 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1479 if (err) 1480 goto err; 1481 1482 err = -ENAMETOOLONG; 1483 if (outarg.namelen > FUSE_NAME_MAX) 1484 goto err; 1485 1486 err = -EINVAL; 1487 if (size != sizeof(outarg) + outarg.namelen + 1) 1488 goto err; 1489 1490 name.name = buf; 1491 name.len = outarg.namelen; 1492 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1493 if (err) 1494 goto err; 1495 fuse_copy_finish(cs); 1496 buf[outarg.namelen] = 0; 1497 1498 down_read(&fc->killsb); 1499 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name); 1500 up_read(&fc->killsb); 1501 kfree(buf); 1502 return err; 1503 1504 err: 1505 kfree(buf); 1506 fuse_copy_finish(cs); 1507 return err; 1508 } 1509 1510 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1511 struct fuse_copy_state *cs) 1512 { 1513 struct fuse_notify_delete_out outarg; 1514 int err = -ENOMEM; 1515 char *buf; 1516 struct qstr name; 1517 1518 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1519 if (!buf) 1520 goto err; 1521 1522 err = -EINVAL; 1523 if (size < sizeof(outarg)) 1524 goto err; 1525 1526 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1527 if (err) 1528 goto err; 1529 1530 err = -ENAMETOOLONG; 1531 if (outarg.namelen > FUSE_NAME_MAX) 1532 goto err; 1533 1534 err = -EINVAL; 1535 if (size != sizeof(outarg) + outarg.namelen + 1) 1536 goto err; 1537 1538 name.name = buf; 1539 name.len = outarg.namelen; 1540 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1541 if (err) 1542 goto err; 1543 fuse_copy_finish(cs); 1544 buf[outarg.namelen] = 0; 1545 1546 down_read(&fc->killsb); 1547 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name); 1548 up_read(&fc->killsb); 1549 kfree(buf); 1550 return err; 1551 1552 err: 1553 kfree(buf); 1554 fuse_copy_finish(cs); 1555 return err; 1556 } 1557 1558 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1559 struct fuse_copy_state *cs) 1560 { 1561 struct fuse_notify_store_out outarg; 1562 struct inode *inode; 1563 struct address_space *mapping; 1564 u64 nodeid; 1565 int err; 1566 pgoff_t index; 1567 unsigned int offset; 1568 unsigned int num; 1569 loff_t file_size; 1570 loff_t end; 1571 1572 err = -EINVAL; 1573 if (size < sizeof(outarg)) 1574 goto out_finish; 1575 1576 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1577 if (err) 1578 goto out_finish; 1579 1580 err = -EINVAL; 1581 if (size - sizeof(outarg) != outarg.size) 1582 goto out_finish; 1583 1584 nodeid = outarg.nodeid; 1585 1586 down_read(&fc->killsb); 1587 1588 err = -ENOENT; 1589 inode = fuse_ilookup(fc, nodeid, NULL); 1590 if (!inode) 1591 goto out_up_killsb; 1592 1593 mapping = inode->i_mapping; 1594 index = outarg.offset >> PAGE_SHIFT; 1595 offset = outarg.offset & ~PAGE_MASK; 1596 file_size = i_size_read(inode); 1597 end = outarg.offset + outarg.size; 1598 if (end > file_size) { 1599 file_size = end; 1600 fuse_write_update_attr(inode, file_size, outarg.size); 1601 } 1602 1603 num = outarg.size; 1604 while (num) { 1605 struct page *page; 1606 unsigned int this_num; 1607 1608 err = -ENOMEM; 1609 page = find_or_create_page(mapping, index, 1610 mapping_gfp_mask(mapping)); 1611 if (!page) 1612 goto out_iput; 1613 1614 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1615 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1616 if (!err && offset == 0 && 1617 (this_num == PAGE_SIZE || file_size == end)) 1618 SetPageUptodate(page); 1619 unlock_page(page); 1620 put_page(page); 1621 1622 if (err) 1623 goto out_iput; 1624 1625 num -= this_num; 1626 offset = 0; 1627 index++; 1628 } 1629 1630 err = 0; 1631 1632 out_iput: 1633 iput(inode); 1634 out_up_killsb: 1635 up_read(&fc->killsb); 1636 out_finish: 1637 fuse_copy_finish(cs); 1638 return err; 1639 } 1640 1641 struct fuse_retrieve_args { 1642 struct fuse_args_pages ap; 1643 struct fuse_notify_retrieve_in inarg; 1644 }; 1645 1646 static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args, 1647 int error) 1648 { 1649 struct fuse_retrieve_args *ra = 1650 container_of(args, typeof(*ra), ap.args); 1651 1652 release_pages(ra->ap.pages, ra->ap.num_pages); 1653 kfree(ra); 1654 } 1655 1656 static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode, 1657 struct fuse_notify_retrieve_out *outarg) 1658 { 1659 int err; 1660 struct address_space *mapping = inode->i_mapping; 1661 pgoff_t index; 1662 loff_t file_size; 1663 unsigned int num; 1664 unsigned int offset; 1665 size_t total_len = 0; 1666 unsigned int num_pages; 1667 struct fuse_conn *fc = fm->fc; 1668 struct fuse_retrieve_args *ra; 1669 size_t args_size = sizeof(*ra); 1670 struct fuse_args_pages *ap; 1671 struct fuse_args *args; 1672 1673 offset = outarg->offset & ~PAGE_MASK; 1674 file_size = i_size_read(inode); 1675 1676 num = min(outarg->size, fc->max_write); 1677 if (outarg->offset > file_size) 1678 num = 0; 1679 else if (outarg->offset + num > file_size) 1680 num = file_size - outarg->offset; 1681 1682 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1683 num_pages = min(num_pages, fc->max_pages); 1684 1685 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0])); 1686 1687 ra = kzalloc(args_size, GFP_KERNEL); 1688 if (!ra) 1689 return -ENOMEM; 1690 1691 ap = &ra->ap; 1692 ap->pages = (void *) (ra + 1); 1693 ap->descs = (void *) (ap->pages + num_pages); 1694 1695 args = &ap->args; 1696 args->nodeid = outarg->nodeid; 1697 args->opcode = FUSE_NOTIFY_REPLY; 1698 args->in_numargs = 2; 1699 args->in_pages = true; 1700 args->end = fuse_retrieve_end; 1701 1702 index = outarg->offset >> PAGE_SHIFT; 1703 1704 while (num && ap->num_pages < num_pages) { 1705 struct page *page; 1706 unsigned int this_num; 1707 1708 page = find_get_page(mapping, index); 1709 if (!page) 1710 break; 1711 1712 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1713 ap->pages[ap->num_pages] = page; 1714 ap->descs[ap->num_pages].offset = offset; 1715 ap->descs[ap->num_pages].length = this_num; 1716 ap->num_pages++; 1717 1718 offset = 0; 1719 num -= this_num; 1720 total_len += this_num; 1721 index++; 1722 } 1723 ra->inarg.offset = outarg->offset; 1724 ra->inarg.size = total_len; 1725 args->in_args[0].size = sizeof(ra->inarg); 1726 args->in_args[0].value = &ra->inarg; 1727 args->in_args[1].size = total_len; 1728 1729 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique); 1730 if (err) 1731 fuse_retrieve_end(fm, args, err); 1732 1733 return err; 1734 } 1735 1736 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1737 struct fuse_copy_state *cs) 1738 { 1739 struct fuse_notify_retrieve_out outarg; 1740 struct fuse_mount *fm; 1741 struct inode *inode; 1742 u64 nodeid; 1743 int err; 1744 1745 err = -EINVAL; 1746 if (size != sizeof(outarg)) 1747 goto copy_finish; 1748 1749 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1750 if (err) 1751 goto copy_finish; 1752 1753 fuse_copy_finish(cs); 1754 1755 down_read(&fc->killsb); 1756 err = -ENOENT; 1757 nodeid = outarg.nodeid; 1758 1759 inode = fuse_ilookup(fc, nodeid, &fm); 1760 if (inode) { 1761 err = fuse_retrieve(fm, inode, &outarg); 1762 iput(inode); 1763 } 1764 up_read(&fc->killsb); 1765 1766 return err; 1767 1768 copy_finish: 1769 fuse_copy_finish(cs); 1770 return err; 1771 } 1772 1773 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1774 unsigned int size, struct fuse_copy_state *cs) 1775 { 1776 /* Don't try to move pages (yet) */ 1777 cs->move_pages = 0; 1778 1779 switch (code) { 1780 case FUSE_NOTIFY_POLL: 1781 return fuse_notify_poll(fc, size, cs); 1782 1783 case FUSE_NOTIFY_INVAL_INODE: 1784 return fuse_notify_inval_inode(fc, size, cs); 1785 1786 case FUSE_NOTIFY_INVAL_ENTRY: 1787 return fuse_notify_inval_entry(fc, size, cs); 1788 1789 case FUSE_NOTIFY_STORE: 1790 return fuse_notify_store(fc, size, cs); 1791 1792 case FUSE_NOTIFY_RETRIEVE: 1793 return fuse_notify_retrieve(fc, size, cs); 1794 1795 case FUSE_NOTIFY_DELETE: 1796 return fuse_notify_delete(fc, size, cs); 1797 1798 default: 1799 fuse_copy_finish(cs); 1800 return -EINVAL; 1801 } 1802 } 1803 1804 /* Look up request on processing list by unique ID */ 1805 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1806 { 1807 unsigned int hash = fuse_req_hash(unique); 1808 struct fuse_req *req; 1809 1810 list_for_each_entry(req, &fpq->processing[hash], list) { 1811 if (req->in.h.unique == unique) 1812 return req; 1813 } 1814 return NULL; 1815 } 1816 1817 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, 1818 unsigned nbytes) 1819 { 1820 unsigned reqsize = sizeof(struct fuse_out_header); 1821 1822 reqsize += fuse_len_args(args->out_numargs, args->out_args); 1823 1824 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar)) 1825 return -EINVAL; 1826 else if (reqsize > nbytes) { 1827 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1]; 1828 unsigned diffsize = reqsize - nbytes; 1829 1830 if (diffsize > lastarg->size) 1831 return -EINVAL; 1832 lastarg->size -= diffsize; 1833 } 1834 return fuse_copy_args(cs, args->out_numargs, args->out_pages, 1835 args->out_args, args->page_zeroing); 1836 } 1837 1838 /* 1839 * Write a single reply to a request. First the header is copied from 1840 * the write buffer. The request is then searched on the processing 1841 * list by the unique ID found in the header. If found, then remove 1842 * it from the list and copy the rest of the buffer to the request. 1843 * The request is finished by calling fuse_request_end(). 1844 */ 1845 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1846 struct fuse_copy_state *cs, size_t nbytes) 1847 { 1848 int err; 1849 struct fuse_conn *fc = fud->fc; 1850 struct fuse_pqueue *fpq = &fud->pq; 1851 struct fuse_req *req; 1852 struct fuse_out_header oh; 1853 1854 err = -EINVAL; 1855 if (nbytes < sizeof(struct fuse_out_header)) 1856 goto out; 1857 1858 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1859 if (err) 1860 goto copy_finish; 1861 1862 err = -EINVAL; 1863 if (oh.len != nbytes) 1864 goto copy_finish; 1865 1866 /* 1867 * Zero oh.unique indicates unsolicited notification message 1868 * and error contains notification code. 1869 */ 1870 if (!oh.unique) { 1871 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1872 goto out; 1873 } 1874 1875 err = -EINVAL; 1876 if (oh.error <= -512 || oh.error > 0) 1877 goto copy_finish; 1878 1879 spin_lock(&fpq->lock); 1880 req = NULL; 1881 if (fpq->connected) 1882 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT); 1883 1884 err = -ENOENT; 1885 if (!req) { 1886 spin_unlock(&fpq->lock); 1887 goto copy_finish; 1888 } 1889 1890 /* Is it an interrupt reply ID? */ 1891 if (oh.unique & FUSE_INT_REQ_BIT) { 1892 __fuse_get_request(req); 1893 spin_unlock(&fpq->lock); 1894 1895 err = 0; 1896 if (nbytes != sizeof(struct fuse_out_header)) 1897 err = -EINVAL; 1898 else if (oh.error == -ENOSYS) 1899 fc->no_interrupt = 1; 1900 else if (oh.error == -EAGAIN) 1901 err = queue_interrupt(req); 1902 1903 fuse_put_request(req); 1904 1905 goto copy_finish; 1906 } 1907 1908 clear_bit(FR_SENT, &req->flags); 1909 list_move(&req->list, &fpq->io); 1910 req->out.h = oh; 1911 set_bit(FR_LOCKED, &req->flags); 1912 spin_unlock(&fpq->lock); 1913 cs->req = req; 1914 if (!req->args->page_replace) 1915 cs->move_pages = 0; 1916 1917 if (oh.error) 1918 err = nbytes != sizeof(oh) ? -EINVAL : 0; 1919 else 1920 err = copy_out_args(cs, req->args, nbytes); 1921 fuse_copy_finish(cs); 1922 1923 spin_lock(&fpq->lock); 1924 clear_bit(FR_LOCKED, &req->flags); 1925 if (!fpq->connected) 1926 err = -ENOENT; 1927 else if (err) 1928 req->out.h.error = -EIO; 1929 if (!test_bit(FR_PRIVATE, &req->flags)) 1930 list_del_init(&req->list); 1931 spin_unlock(&fpq->lock); 1932 1933 fuse_request_end(req); 1934 out: 1935 return err ? err : nbytes; 1936 1937 copy_finish: 1938 fuse_copy_finish(cs); 1939 goto out; 1940 } 1941 1942 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1943 { 1944 struct fuse_copy_state cs; 1945 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1946 1947 if (!fud) 1948 return -EPERM; 1949 1950 if (!iter_is_iovec(from)) 1951 return -EINVAL; 1952 1953 fuse_copy_init(&cs, 0, from); 1954 1955 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1956 } 1957 1958 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1959 struct file *out, loff_t *ppos, 1960 size_t len, unsigned int flags) 1961 { 1962 unsigned int head, tail, mask, count; 1963 unsigned nbuf; 1964 unsigned idx; 1965 struct pipe_buffer *bufs; 1966 struct fuse_copy_state cs; 1967 struct fuse_dev *fud; 1968 size_t rem; 1969 ssize_t ret; 1970 1971 fud = fuse_get_dev(out); 1972 if (!fud) 1973 return -EPERM; 1974 1975 pipe_lock(pipe); 1976 1977 head = pipe->head; 1978 tail = pipe->tail; 1979 mask = pipe->ring_size - 1; 1980 count = head - tail; 1981 1982 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL); 1983 if (!bufs) { 1984 pipe_unlock(pipe); 1985 return -ENOMEM; 1986 } 1987 1988 nbuf = 0; 1989 rem = 0; 1990 for (idx = tail; idx != head && rem < len; idx++) 1991 rem += pipe->bufs[idx & mask].len; 1992 1993 ret = -EINVAL; 1994 if (rem < len) 1995 goto out_free; 1996 1997 rem = len; 1998 while (rem) { 1999 struct pipe_buffer *ibuf; 2000 struct pipe_buffer *obuf; 2001 2002 if (WARN_ON(nbuf >= count || tail == head)) 2003 goto out_free; 2004 2005 ibuf = &pipe->bufs[tail & mask]; 2006 obuf = &bufs[nbuf]; 2007 2008 if (rem >= ibuf->len) { 2009 *obuf = *ibuf; 2010 ibuf->ops = NULL; 2011 tail++; 2012 pipe->tail = tail; 2013 } else { 2014 if (!pipe_buf_get(pipe, ibuf)) 2015 goto out_free; 2016 2017 *obuf = *ibuf; 2018 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 2019 obuf->len = rem; 2020 ibuf->offset += obuf->len; 2021 ibuf->len -= obuf->len; 2022 } 2023 nbuf++; 2024 rem -= obuf->len; 2025 } 2026 pipe_unlock(pipe); 2027 2028 fuse_copy_init(&cs, 0, NULL); 2029 cs.pipebufs = bufs; 2030 cs.nr_segs = nbuf; 2031 cs.pipe = pipe; 2032 2033 if (flags & SPLICE_F_MOVE) 2034 cs.move_pages = 1; 2035 2036 ret = fuse_dev_do_write(fud, &cs, len); 2037 2038 pipe_lock(pipe); 2039 out_free: 2040 for (idx = 0; idx < nbuf; idx++) { 2041 struct pipe_buffer *buf = &bufs[idx]; 2042 2043 if (buf->ops) 2044 pipe_buf_release(pipe, buf); 2045 } 2046 pipe_unlock(pipe); 2047 2048 kvfree(bufs); 2049 return ret; 2050 } 2051 2052 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait) 2053 { 2054 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 2055 struct fuse_iqueue *fiq; 2056 struct fuse_dev *fud = fuse_get_dev(file); 2057 2058 if (!fud) 2059 return EPOLLERR; 2060 2061 fiq = &fud->fc->iq; 2062 poll_wait(file, &fiq->waitq, wait); 2063 2064 spin_lock(&fiq->lock); 2065 if (!fiq->connected) 2066 mask = EPOLLERR; 2067 else if (request_pending(fiq)) 2068 mask |= EPOLLIN | EPOLLRDNORM; 2069 spin_unlock(&fiq->lock); 2070 2071 return mask; 2072 } 2073 2074 /* Abort all requests on the given list (pending or processing) */ 2075 static void end_requests(struct list_head *head) 2076 { 2077 while (!list_empty(head)) { 2078 struct fuse_req *req; 2079 req = list_entry(head->next, struct fuse_req, list); 2080 req->out.h.error = -ECONNABORTED; 2081 clear_bit(FR_SENT, &req->flags); 2082 list_del_init(&req->list); 2083 fuse_request_end(req); 2084 } 2085 } 2086 2087 static void end_polls(struct fuse_conn *fc) 2088 { 2089 struct rb_node *p; 2090 2091 p = rb_first(&fc->polled_files); 2092 2093 while (p) { 2094 struct fuse_file *ff; 2095 ff = rb_entry(p, struct fuse_file, polled_node); 2096 wake_up_interruptible_all(&ff->poll_wait); 2097 2098 p = rb_next(p); 2099 } 2100 } 2101 2102 /* 2103 * Abort all requests. 2104 * 2105 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2106 * filesystem. 2107 * 2108 * The same effect is usually achievable through killing the filesystem daemon 2109 * and all users of the filesystem. The exception is the combination of an 2110 * asynchronous request and the tricky deadlock (see 2111 * Documentation/filesystems/fuse.rst). 2112 * 2113 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2114 * requests, they should be finished off immediately. Locked requests will be 2115 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2116 * requests. It is possible that some request will finish before we can. This 2117 * is OK, the request will in that case be removed from the list before we touch 2118 * it. 2119 */ 2120 void fuse_abort_conn(struct fuse_conn *fc) 2121 { 2122 struct fuse_iqueue *fiq = &fc->iq; 2123 2124 spin_lock(&fc->lock); 2125 if (fc->connected) { 2126 struct fuse_dev *fud; 2127 struct fuse_req *req, *next; 2128 LIST_HEAD(to_end); 2129 unsigned int i; 2130 2131 /* Background queuing checks fc->connected under bg_lock */ 2132 spin_lock(&fc->bg_lock); 2133 fc->connected = 0; 2134 spin_unlock(&fc->bg_lock); 2135 2136 fuse_set_initialized(fc); 2137 list_for_each_entry(fud, &fc->devices, entry) { 2138 struct fuse_pqueue *fpq = &fud->pq; 2139 2140 spin_lock(&fpq->lock); 2141 fpq->connected = 0; 2142 list_for_each_entry_safe(req, next, &fpq->io, list) { 2143 req->out.h.error = -ECONNABORTED; 2144 spin_lock(&req->waitq.lock); 2145 set_bit(FR_ABORTED, &req->flags); 2146 if (!test_bit(FR_LOCKED, &req->flags)) { 2147 set_bit(FR_PRIVATE, &req->flags); 2148 __fuse_get_request(req); 2149 list_move(&req->list, &to_end); 2150 } 2151 spin_unlock(&req->waitq.lock); 2152 } 2153 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2154 list_splice_tail_init(&fpq->processing[i], 2155 &to_end); 2156 spin_unlock(&fpq->lock); 2157 } 2158 spin_lock(&fc->bg_lock); 2159 fc->blocked = 0; 2160 fc->max_background = UINT_MAX; 2161 flush_bg_queue(fc); 2162 spin_unlock(&fc->bg_lock); 2163 2164 spin_lock(&fiq->lock); 2165 fiq->connected = 0; 2166 list_for_each_entry(req, &fiq->pending, list) 2167 clear_bit(FR_PENDING, &req->flags); 2168 list_splice_tail_init(&fiq->pending, &to_end); 2169 while (forget_pending(fiq)) 2170 kfree(fuse_dequeue_forget(fiq, 1, NULL)); 2171 wake_up_all(&fiq->waitq); 2172 spin_unlock(&fiq->lock); 2173 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2174 end_polls(fc); 2175 wake_up_all(&fc->blocked_waitq); 2176 spin_unlock(&fc->lock); 2177 2178 end_requests(&to_end); 2179 } else { 2180 spin_unlock(&fc->lock); 2181 } 2182 } 2183 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2184 2185 void fuse_wait_aborted(struct fuse_conn *fc) 2186 { 2187 /* matches implicit memory barrier in fuse_drop_waiting() */ 2188 smp_mb(); 2189 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0); 2190 } 2191 2192 int fuse_dev_release(struct inode *inode, struct file *file) 2193 { 2194 struct fuse_dev *fud = fuse_get_dev(file); 2195 2196 if (fud) { 2197 struct fuse_conn *fc = fud->fc; 2198 struct fuse_pqueue *fpq = &fud->pq; 2199 LIST_HEAD(to_end); 2200 unsigned int i; 2201 2202 spin_lock(&fpq->lock); 2203 WARN_ON(!list_empty(&fpq->io)); 2204 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2205 list_splice_init(&fpq->processing[i], &to_end); 2206 spin_unlock(&fpq->lock); 2207 2208 end_requests(&to_end); 2209 2210 /* Are we the last open device? */ 2211 if (atomic_dec_and_test(&fc->dev_count)) { 2212 WARN_ON(fc->iq.fasync != NULL); 2213 fuse_abort_conn(fc); 2214 } 2215 fuse_dev_free(fud); 2216 } 2217 return 0; 2218 } 2219 EXPORT_SYMBOL_GPL(fuse_dev_release); 2220 2221 static int fuse_dev_fasync(int fd, struct file *file, int on) 2222 { 2223 struct fuse_dev *fud = fuse_get_dev(file); 2224 2225 if (!fud) 2226 return -EPERM; 2227 2228 /* No locking - fasync_helper does its own locking */ 2229 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2230 } 2231 2232 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2233 { 2234 struct fuse_dev *fud; 2235 2236 if (new->private_data) 2237 return -EINVAL; 2238 2239 fud = fuse_dev_alloc_install(fc); 2240 if (!fud) 2241 return -ENOMEM; 2242 2243 new->private_data = fud; 2244 atomic_inc(&fc->dev_count); 2245 2246 return 0; 2247 } 2248 2249 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2250 unsigned long arg) 2251 { 2252 int res; 2253 int oldfd; 2254 struct fuse_dev *fud = NULL; 2255 2256 switch (cmd) { 2257 case FUSE_DEV_IOC_CLONE: 2258 res = -EFAULT; 2259 if (!get_user(oldfd, (__u32 __user *)arg)) { 2260 struct file *old = fget(oldfd); 2261 2262 res = -EINVAL; 2263 if (old) { 2264 /* 2265 * Check against file->f_op because CUSE 2266 * uses the same ioctl handler. 2267 */ 2268 if (old->f_op == file->f_op && 2269 old->f_cred->user_ns == file->f_cred->user_ns) 2270 fud = fuse_get_dev(old); 2271 2272 if (fud) { 2273 mutex_lock(&fuse_mutex); 2274 res = fuse_device_clone(fud->fc, file); 2275 mutex_unlock(&fuse_mutex); 2276 } 2277 fput(old); 2278 } 2279 } 2280 break; 2281 default: 2282 res = -ENOTTY; 2283 break; 2284 } 2285 return res; 2286 } 2287 2288 const struct file_operations fuse_dev_operations = { 2289 .owner = THIS_MODULE, 2290 .open = fuse_dev_open, 2291 .llseek = no_llseek, 2292 .read_iter = fuse_dev_read, 2293 .splice_read = fuse_dev_splice_read, 2294 .write_iter = fuse_dev_write, 2295 .splice_write = fuse_dev_splice_write, 2296 .poll = fuse_dev_poll, 2297 .release = fuse_dev_release, 2298 .fasync = fuse_dev_fasync, 2299 .unlocked_ioctl = fuse_dev_ioctl, 2300 .compat_ioctl = compat_ptr_ioctl, 2301 }; 2302 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2303 2304 static struct miscdevice fuse_miscdevice = { 2305 .minor = FUSE_MINOR, 2306 .name = "fuse", 2307 .fops = &fuse_dev_operations, 2308 }; 2309 2310 int __init fuse_dev_init(void) 2311 { 2312 int err = -ENOMEM; 2313 fuse_req_cachep = kmem_cache_create("fuse_request", 2314 sizeof(struct fuse_req), 2315 0, 0, NULL); 2316 if (!fuse_req_cachep) 2317 goto out; 2318 2319 err = misc_register(&fuse_miscdevice); 2320 if (err) 2321 goto out_cache_clean; 2322 2323 return 0; 2324 2325 out_cache_clean: 2326 kmem_cache_destroy(fuse_req_cachep); 2327 out: 2328 return err; 2329 } 2330 2331 void fuse_dev_cleanup(void) 2332 { 2333 misc_deregister(&fuse_miscdevice); 2334 kmem_cache_destroy(fuse_req_cachep); 2335 } 2336