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_atomic(cs->pg); 760 void *buf = pgaddr + cs->offset; 761 762 if (cs->write) 763 memcpy(buf, *val, ncpy); 764 else 765 memcpy(*val, buf, ncpy); 766 767 kunmap_atomic(pgaddr); 768 *val += ncpy; 769 } 770 *size -= ncpy; 771 cs->len -= ncpy; 772 cs->offset += ncpy; 773 return ncpy; 774 } 775 776 static int fuse_check_page(struct page *page) 777 { 778 if (page_mapcount(page) || 779 page->mapping != NULL || 780 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 781 ~(1 << PG_locked | 782 1 << PG_referenced | 783 1 << PG_uptodate | 784 1 << PG_lru | 785 1 << PG_active | 786 1 << PG_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 err = 0; 856 spin_lock(&cs->req->waitq.lock); 857 if (test_bit(FR_ABORTED, &cs->req->flags)) 858 err = -ENOENT; 859 else 860 *pagep = newpage; 861 spin_unlock(&cs->req->waitq.lock); 862 863 if (err) { 864 unlock_page(newpage); 865 put_page(newpage); 866 goto out_put_old; 867 } 868 869 unlock_page(oldpage); 870 /* Drop ref for ap->pages[] array */ 871 put_page(oldpage); 872 cs->len = 0; 873 874 err = 0; 875 out_put_old: 876 /* Drop ref obtained in this function */ 877 put_page(oldpage); 878 return err; 879 880 out_fallback_unlock: 881 unlock_page(newpage); 882 out_fallback: 883 cs->pg = buf->page; 884 cs->offset = buf->offset; 885 886 err = lock_request(cs->req); 887 if (!err) 888 err = 1; 889 890 goto out_put_old; 891 } 892 893 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 894 unsigned offset, unsigned count) 895 { 896 struct pipe_buffer *buf; 897 int err; 898 899 if (cs->nr_segs >= cs->pipe->max_usage) 900 return -EIO; 901 902 get_page(page); 903 err = unlock_request(cs->req); 904 if (err) { 905 put_page(page); 906 return err; 907 } 908 909 fuse_copy_finish(cs); 910 911 buf = cs->pipebufs; 912 buf->page = page; 913 buf->offset = offset; 914 buf->len = count; 915 916 cs->pipebufs++; 917 cs->nr_segs++; 918 cs->len = 0; 919 920 return 0; 921 } 922 923 /* 924 * Copy a page in the request to/from the userspace buffer. Must be 925 * done atomically 926 */ 927 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 928 unsigned offset, unsigned count, int zeroing) 929 { 930 int err; 931 struct page *page = *pagep; 932 933 if (page && zeroing && count < PAGE_SIZE) 934 clear_highpage(page); 935 936 while (count) { 937 if (cs->write && cs->pipebufs && page) { 938 return fuse_ref_page(cs, page, offset, count); 939 } else if (!cs->len) { 940 if (cs->move_pages && page && 941 offset == 0 && count == PAGE_SIZE) { 942 err = fuse_try_move_page(cs, pagep); 943 if (err <= 0) 944 return err; 945 } else { 946 err = fuse_copy_fill(cs); 947 if (err) 948 return err; 949 } 950 } 951 if (page) { 952 void *mapaddr = kmap_atomic(page); 953 void *buf = mapaddr + offset; 954 offset += fuse_copy_do(cs, &buf, &count); 955 kunmap_atomic(mapaddr); 956 } else 957 offset += fuse_copy_do(cs, NULL, &count); 958 } 959 if (page && !cs->write) 960 flush_dcache_page(page); 961 return 0; 962 } 963 964 /* Copy pages in the request to/from userspace buffer */ 965 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 966 int zeroing) 967 { 968 unsigned i; 969 struct fuse_req *req = cs->req; 970 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args); 971 972 973 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) { 974 int err; 975 unsigned int offset = ap->descs[i].offset; 976 unsigned int count = min(nbytes, ap->descs[i].length); 977 978 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing); 979 if (err) 980 return err; 981 982 nbytes -= count; 983 } 984 return 0; 985 } 986 987 /* Copy a single argument in the request to/from userspace buffer */ 988 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 989 { 990 while (size) { 991 if (!cs->len) { 992 int err = fuse_copy_fill(cs); 993 if (err) 994 return err; 995 } 996 fuse_copy_do(cs, &val, &size); 997 } 998 return 0; 999 } 1000 1001 /* Copy request arguments to/from userspace buffer */ 1002 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1003 unsigned argpages, struct fuse_arg *args, 1004 int zeroing) 1005 { 1006 int err = 0; 1007 unsigned i; 1008 1009 for (i = 0; !err && i < numargs; i++) { 1010 struct fuse_arg *arg = &args[i]; 1011 if (i == numargs - 1 && argpages) 1012 err = fuse_copy_pages(cs, arg->size, zeroing); 1013 else 1014 err = fuse_copy_one(cs, arg->value, arg->size); 1015 } 1016 return err; 1017 } 1018 1019 static int forget_pending(struct fuse_iqueue *fiq) 1020 { 1021 return fiq->forget_list_head.next != NULL; 1022 } 1023 1024 static int request_pending(struct fuse_iqueue *fiq) 1025 { 1026 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1027 forget_pending(fiq); 1028 } 1029 1030 /* 1031 * Transfer an interrupt request to userspace 1032 * 1033 * Unlike other requests this is assembled on demand, without a need 1034 * to allocate a separate fuse_req structure. 1035 * 1036 * Called with fiq->lock held, releases it 1037 */ 1038 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1039 struct fuse_copy_state *cs, 1040 size_t nbytes, struct fuse_req *req) 1041 __releases(fiq->lock) 1042 { 1043 struct fuse_in_header ih; 1044 struct fuse_interrupt_in arg; 1045 unsigned reqsize = sizeof(ih) + sizeof(arg); 1046 int err; 1047 1048 list_del_init(&req->intr_entry); 1049 memset(&ih, 0, sizeof(ih)); 1050 memset(&arg, 0, sizeof(arg)); 1051 ih.len = reqsize; 1052 ih.opcode = FUSE_INTERRUPT; 1053 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT); 1054 arg.unique = req->in.h.unique; 1055 1056 spin_unlock(&fiq->lock); 1057 if (nbytes < reqsize) 1058 return -EINVAL; 1059 1060 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1061 if (!err) 1062 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1063 fuse_copy_finish(cs); 1064 1065 return err ? err : reqsize; 1066 } 1067 1068 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq, 1069 unsigned int max, 1070 unsigned int *countp) 1071 { 1072 struct fuse_forget_link *head = fiq->forget_list_head.next; 1073 struct fuse_forget_link **newhead = &head; 1074 unsigned count; 1075 1076 for (count = 0; *newhead != NULL && count < max; count++) 1077 newhead = &(*newhead)->next; 1078 1079 fiq->forget_list_head.next = *newhead; 1080 *newhead = NULL; 1081 if (fiq->forget_list_head.next == NULL) 1082 fiq->forget_list_tail = &fiq->forget_list_head; 1083 1084 if (countp != NULL) 1085 *countp = count; 1086 1087 return head; 1088 } 1089 EXPORT_SYMBOL(fuse_dequeue_forget); 1090 1091 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1092 struct fuse_copy_state *cs, 1093 size_t nbytes) 1094 __releases(fiq->lock) 1095 { 1096 int err; 1097 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL); 1098 struct fuse_forget_in arg = { 1099 .nlookup = forget->forget_one.nlookup, 1100 }; 1101 struct fuse_in_header ih = { 1102 .opcode = FUSE_FORGET, 1103 .nodeid = forget->forget_one.nodeid, 1104 .unique = fuse_get_unique(fiq), 1105 .len = sizeof(ih) + sizeof(arg), 1106 }; 1107 1108 spin_unlock(&fiq->lock); 1109 kfree(forget); 1110 if (nbytes < ih.len) 1111 return -EINVAL; 1112 1113 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1114 if (!err) 1115 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1116 fuse_copy_finish(cs); 1117 1118 if (err) 1119 return err; 1120 1121 return ih.len; 1122 } 1123 1124 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1125 struct fuse_copy_state *cs, size_t nbytes) 1126 __releases(fiq->lock) 1127 { 1128 int err; 1129 unsigned max_forgets; 1130 unsigned count; 1131 struct fuse_forget_link *head; 1132 struct fuse_batch_forget_in arg = { .count = 0 }; 1133 struct fuse_in_header ih = { 1134 .opcode = FUSE_BATCH_FORGET, 1135 .unique = fuse_get_unique(fiq), 1136 .len = sizeof(ih) + sizeof(arg), 1137 }; 1138 1139 if (nbytes < ih.len) { 1140 spin_unlock(&fiq->lock); 1141 return -EINVAL; 1142 } 1143 1144 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1145 head = fuse_dequeue_forget(fiq, max_forgets, &count); 1146 spin_unlock(&fiq->lock); 1147 1148 arg.count = count; 1149 ih.len += count * sizeof(struct fuse_forget_one); 1150 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1151 if (!err) 1152 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1153 1154 while (head) { 1155 struct fuse_forget_link *forget = head; 1156 1157 if (!err) { 1158 err = fuse_copy_one(cs, &forget->forget_one, 1159 sizeof(forget->forget_one)); 1160 } 1161 head = forget->next; 1162 kfree(forget); 1163 } 1164 1165 fuse_copy_finish(cs); 1166 1167 if (err) 1168 return err; 1169 1170 return ih.len; 1171 } 1172 1173 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1174 struct fuse_copy_state *cs, 1175 size_t nbytes) 1176 __releases(fiq->lock) 1177 { 1178 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1179 return fuse_read_single_forget(fiq, cs, nbytes); 1180 else 1181 return fuse_read_batch_forget(fiq, cs, nbytes); 1182 } 1183 1184 /* 1185 * Read a single request into the userspace filesystem's buffer. This 1186 * function waits until a request is available, then removes it from 1187 * the pending list and copies request data to userspace buffer. If 1188 * no reply is needed (FORGET) or request has been aborted or there 1189 * was an error during the copying then it's finished by calling 1190 * fuse_request_end(). Otherwise add it to the processing list, and set 1191 * the 'sent' flag. 1192 */ 1193 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1194 struct fuse_copy_state *cs, size_t nbytes) 1195 { 1196 ssize_t err; 1197 struct fuse_conn *fc = fud->fc; 1198 struct fuse_iqueue *fiq = &fc->iq; 1199 struct fuse_pqueue *fpq = &fud->pq; 1200 struct fuse_req *req; 1201 struct fuse_args *args; 1202 unsigned reqsize; 1203 unsigned int hash; 1204 1205 /* 1206 * Require sane minimum read buffer - that has capacity for fixed part 1207 * of any request header + negotiated max_write room for data. 1208 * 1209 * Historically libfuse reserves 4K for fixed header room, but e.g. 1210 * GlusterFS reserves only 80 bytes 1211 * 1212 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)` 1213 * 1214 * which is the absolute minimum any sane filesystem should be using 1215 * for header room. 1216 */ 1217 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 1218 sizeof(struct fuse_in_header) + 1219 sizeof(struct fuse_write_in) + 1220 fc->max_write)) 1221 return -EINVAL; 1222 1223 restart: 1224 for (;;) { 1225 spin_lock(&fiq->lock); 1226 if (!fiq->connected || request_pending(fiq)) 1227 break; 1228 spin_unlock(&fiq->lock); 1229 1230 if (file->f_flags & O_NONBLOCK) 1231 return -EAGAIN; 1232 err = wait_event_interruptible_exclusive(fiq->waitq, 1233 !fiq->connected || request_pending(fiq)); 1234 if (err) 1235 return err; 1236 } 1237 1238 if (!fiq->connected) { 1239 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1240 goto err_unlock; 1241 } 1242 1243 if (!list_empty(&fiq->interrupts)) { 1244 req = list_entry(fiq->interrupts.next, struct fuse_req, 1245 intr_entry); 1246 return fuse_read_interrupt(fiq, cs, nbytes, req); 1247 } 1248 1249 if (forget_pending(fiq)) { 1250 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1251 return fuse_read_forget(fc, fiq, cs, nbytes); 1252 1253 if (fiq->forget_batch <= -8) 1254 fiq->forget_batch = 16; 1255 } 1256 1257 req = list_entry(fiq->pending.next, struct fuse_req, list); 1258 clear_bit(FR_PENDING, &req->flags); 1259 list_del_init(&req->list); 1260 spin_unlock(&fiq->lock); 1261 1262 args = req->args; 1263 reqsize = req->in.h.len; 1264 1265 /* If request is too large, reply with an error and restart the read */ 1266 if (nbytes < reqsize) { 1267 req->out.h.error = -EIO; 1268 /* SETXATTR is special, since it may contain too large data */ 1269 if (args->opcode == FUSE_SETXATTR) 1270 req->out.h.error = -E2BIG; 1271 fuse_request_end(req); 1272 goto restart; 1273 } 1274 spin_lock(&fpq->lock); 1275 /* 1276 * Must not put request on fpq->io queue after having been shut down by 1277 * fuse_abort_conn() 1278 */ 1279 if (!fpq->connected) { 1280 req->out.h.error = err = -ECONNABORTED; 1281 goto out_end; 1282 1283 } 1284 list_add(&req->list, &fpq->io); 1285 spin_unlock(&fpq->lock); 1286 cs->req = req; 1287 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h)); 1288 if (!err) 1289 err = fuse_copy_args(cs, args->in_numargs, args->in_pages, 1290 (struct fuse_arg *) args->in_args, 0); 1291 fuse_copy_finish(cs); 1292 spin_lock(&fpq->lock); 1293 clear_bit(FR_LOCKED, &req->flags); 1294 if (!fpq->connected) { 1295 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1296 goto out_end; 1297 } 1298 if (err) { 1299 req->out.h.error = -EIO; 1300 goto out_end; 1301 } 1302 if (!test_bit(FR_ISREPLY, &req->flags)) { 1303 err = reqsize; 1304 goto out_end; 1305 } 1306 hash = fuse_req_hash(req->in.h.unique); 1307 list_move_tail(&req->list, &fpq->processing[hash]); 1308 __fuse_get_request(req); 1309 set_bit(FR_SENT, &req->flags); 1310 spin_unlock(&fpq->lock); 1311 /* matches barrier in request_wait_answer() */ 1312 smp_mb__after_atomic(); 1313 if (test_bit(FR_INTERRUPTED, &req->flags)) 1314 queue_interrupt(req); 1315 fuse_put_request(req); 1316 1317 return reqsize; 1318 1319 out_end: 1320 if (!test_bit(FR_PRIVATE, &req->flags)) 1321 list_del_init(&req->list); 1322 spin_unlock(&fpq->lock); 1323 fuse_request_end(req); 1324 return err; 1325 1326 err_unlock: 1327 spin_unlock(&fiq->lock); 1328 return err; 1329 } 1330 1331 static int fuse_dev_open(struct inode *inode, struct file *file) 1332 { 1333 /* 1334 * The fuse device's file's private_data is used to hold 1335 * the fuse_conn(ection) when it is mounted, and is used to 1336 * keep track of whether the file has been mounted already. 1337 */ 1338 file->private_data = NULL; 1339 return 0; 1340 } 1341 1342 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1343 { 1344 struct fuse_copy_state cs; 1345 struct file *file = iocb->ki_filp; 1346 struct fuse_dev *fud = fuse_get_dev(file); 1347 1348 if (!fud) 1349 return -EPERM; 1350 1351 if (!iter_is_iovec(to)) 1352 return -EINVAL; 1353 1354 fuse_copy_init(&cs, 1, to); 1355 1356 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1357 } 1358 1359 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1360 struct pipe_inode_info *pipe, 1361 size_t len, unsigned int flags) 1362 { 1363 int total, ret; 1364 int page_nr = 0; 1365 struct pipe_buffer *bufs; 1366 struct fuse_copy_state cs; 1367 struct fuse_dev *fud = fuse_get_dev(in); 1368 1369 if (!fud) 1370 return -EPERM; 1371 1372 bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer), 1373 GFP_KERNEL); 1374 if (!bufs) 1375 return -ENOMEM; 1376 1377 fuse_copy_init(&cs, 1, NULL); 1378 cs.pipebufs = bufs; 1379 cs.pipe = pipe; 1380 ret = fuse_dev_do_read(fud, in, &cs, len); 1381 if (ret < 0) 1382 goto out; 1383 1384 if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) { 1385 ret = -EIO; 1386 goto out; 1387 } 1388 1389 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1390 /* 1391 * Need to be careful about this. Having buf->ops in module 1392 * code can Oops if the buffer persists after module unload. 1393 */ 1394 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1395 bufs[page_nr].flags = 0; 1396 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1397 if (unlikely(ret < 0)) 1398 break; 1399 } 1400 if (total) 1401 ret = total; 1402 out: 1403 for (; page_nr < cs.nr_segs; page_nr++) 1404 put_page(bufs[page_nr].page); 1405 1406 kvfree(bufs); 1407 return ret; 1408 } 1409 1410 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1411 struct fuse_copy_state *cs) 1412 { 1413 struct fuse_notify_poll_wakeup_out outarg; 1414 int err = -EINVAL; 1415 1416 if (size != sizeof(outarg)) 1417 goto err; 1418 1419 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1420 if (err) 1421 goto err; 1422 1423 fuse_copy_finish(cs); 1424 return fuse_notify_poll_wakeup(fc, &outarg); 1425 1426 err: 1427 fuse_copy_finish(cs); 1428 return err; 1429 } 1430 1431 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1432 struct fuse_copy_state *cs) 1433 { 1434 struct fuse_notify_inval_inode_out outarg; 1435 int err = -EINVAL; 1436 1437 if (size != sizeof(outarg)) 1438 goto err; 1439 1440 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1441 if (err) 1442 goto err; 1443 fuse_copy_finish(cs); 1444 1445 down_read(&fc->killsb); 1446 err = fuse_reverse_inval_inode(fc, outarg.ino, 1447 outarg.off, outarg.len); 1448 up_read(&fc->killsb); 1449 return err; 1450 1451 err: 1452 fuse_copy_finish(cs); 1453 return err; 1454 } 1455 1456 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1457 struct fuse_copy_state *cs) 1458 { 1459 struct fuse_notify_inval_entry_out outarg; 1460 int err = -ENOMEM; 1461 char *buf; 1462 struct qstr name; 1463 1464 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1465 if (!buf) 1466 goto err; 1467 1468 err = -EINVAL; 1469 if (size < sizeof(outarg)) 1470 goto err; 1471 1472 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1473 if (err) 1474 goto err; 1475 1476 err = -ENAMETOOLONG; 1477 if (outarg.namelen > FUSE_NAME_MAX) 1478 goto err; 1479 1480 err = -EINVAL; 1481 if (size != sizeof(outarg) + outarg.namelen + 1) 1482 goto err; 1483 1484 name.name = buf; 1485 name.len = outarg.namelen; 1486 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1487 if (err) 1488 goto err; 1489 fuse_copy_finish(cs); 1490 buf[outarg.namelen] = 0; 1491 1492 down_read(&fc->killsb); 1493 err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name); 1494 up_read(&fc->killsb); 1495 kfree(buf); 1496 return err; 1497 1498 err: 1499 kfree(buf); 1500 fuse_copy_finish(cs); 1501 return err; 1502 } 1503 1504 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1505 struct fuse_copy_state *cs) 1506 { 1507 struct fuse_notify_delete_out outarg; 1508 int err = -ENOMEM; 1509 char *buf; 1510 struct qstr name; 1511 1512 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1513 if (!buf) 1514 goto err; 1515 1516 err = -EINVAL; 1517 if (size < sizeof(outarg)) 1518 goto err; 1519 1520 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1521 if (err) 1522 goto err; 1523 1524 err = -ENAMETOOLONG; 1525 if (outarg.namelen > FUSE_NAME_MAX) 1526 goto err; 1527 1528 err = -EINVAL; 1529 if (size != sizeof(outarg) + outarg.namelen + 1) 1530 goto err; 1531 1532 name.name = buf; 1533 name.len = outarg.namelen; 1534 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1535 if (err) 1536 goto err; 1537 fuse_copy_finish(cs); 1538 buf[outarg.namelen] = 0; 1539 1540 down_read(&fc->killsb); 1541 err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name); 1542 up_read(&fc->killsb); 1543 kfree(buf); 1544 return err; 1545 1546 err: 1547 kfree(buf); 1548 fuse_copy_finish(cs); 1549 return err; 1550 } 1551 1552 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1553 struct fuse_copy_state *cs) 1554 { 1555 struct fuse_notify_store_out outarg; 1556 struct inode *inode; 1557 struct address_space *mapping; 1558 u64 nodeid; 1559 int err; 1560 pgoff_t index; 1561 unsigned int offset; 1562 unsigned int num; 1563 loff_t file_size; 1564 loff_t end; 1565 1566 err = -EINVAL; 1567 if (size < sizeof(outarg)) 1568 goto out_finish; 1569 1570 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1571 if (err) 1572 goto out_finish; 1573 1574 err = -EINVAL; 1575 if (size - sizeof(outarg) != outarg.size) 1576 goto out_finish; 1577 1578 nodeid = outarg.nodeid; 1579 1580 down_read(&fc->killsb); 1581 1582 err = -ENOENT; 1583 inode = fuse_ilookup(fc, nodeid, NULL); 1584 if (!inode) 1585 goto out_up_killsb; 1586 1587 mapping = inode->i_mapping; 1588 index = outarg.offset >> PAGE_SHIFT; 1589 offset = outarg.offset & ~PAGE_MASK; 1590 file_size = i_size_read(inode); 1591 end = outarg.offset + outarg.size; 1592 if (end > file_size) { 1593 file_size = end; 1594 fuse_write_update_size(inode, file_size); 1595 } 1596 1597 num = outarg.size; 1598 while (num) { 1599 struct page *page; 1600 unsigned int this_num; 1601 1602 err = -ENOMEM; 1603 page = find_or_create_page(mapping, index, 1604 mapping_gfp_mask(mapping)); 1605 if (!page) 1606 goto out_iput; 1607 1608 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1609 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1610 if (!err && offset == 0 && 1611 (this_num == PAGE_SIZE || file_size == end)) 1612 SetPageUptodate(page); 1613 unlock_page(page); 1614 put_page(page); 1615 1616 if (err) 1617 goto out_iput; 1618 1619 num -= this_num; 1620 offset = 0; 1621 index++; 1622 } 1623 1624 err = 0; 1625 1626 out_iput: 1627 iput(inode); 1628 out_up_killsb: 1629 up_read(&fc->killsb); 1630 out_finish: 1631 fuse_copy_finish(cs); 1632 return err; 1633 } 1634 1635 struct fuse_retrieve_args { 1636 struct fuse_args_pages ap; 1637 struct fuse_notify_retrieve_in inarg; 1638 }; 1639 1640 static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args, 1641 int error) 1642 { 1643 struct fuse_retrieve_args *ra = 1644 container_of(args, typeof(*ra), ap.args); 1645 1646 release_pages(ra->ap.pages, ra->ap.num_pages); 1647 kfree(ra); 1648 } 1649 1650 static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode, 1651 struct fuse_notify_retrieve_out *outarg) 1652 { 1653 int err; 1654 struct address_space *mapping = inode->i_mapping; 1655 pgoff_t index; 1656 loff_t file_size; 1657 unsigned int num; 1658 unsigned int offset; 1659 size_t total_len = 0; 1660 unsigned int num_pages; 1661 struct fuse_conn *fc = fm->fc; 1662 struct fuse_retrieve_args *ra; 1663 size_t args_size = sizeof(*ra); 1664 struct fuse_args_pages *ap; 1665 struct fuse_args *args; 1666 1667 offset = outarg->offset & ~PAGE_MASK; 1668 file_size = i_size_read(inode); 1669 1670 num = min(outarg->size, fc->max_write); 1671 if (outarg->offset > file_size) 1672 num = 0; 1673 else if (outarg->offset + num > file_size) 1674 num = file_size - outarg->offset; 1675 1676 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1677 num_pages = min(num_pages, fc->max_pages); 1678 1679 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0])); 1680 1681 ra = kzalloc(args_size, GFP_KERNEL); 1682 if (!ra) 1683 return -ENOMEM; 1684 1685 ap = &ra->ap; 1686 ap->pages = (void *) (ra + 1); 1687 ap->descs = (void *) (ap->pages + num_pages); 1688 1689 args = &ap->args; 1690 args->nodeid = outarg->nodeid; 1691 args->opcode = FUSE_NOTIFY_REPLY; 1692 args->in_numargs = 2; 1693 args->in_pages = true; 1694 args->end = fuse_retrieve_end; 1695 1696 index = outarg->offset >> PAGE_SHIFT; 1697 1698 while (num && ap->num_pages < num_pages) { 1699 struct page *page; 1700 unsigned int this_num; 1701 1702 page = find_get_page(mapping, index); 1703 if (!page) 1704 break; 1705 1706 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1707 ap->pages[ap->num_pages] = page; 1708 ap->descs[ap->num_pages].offset = offset; 1709 ap->descs[ap->num_pages].length = this_num; 1710 ap->num_pages++; 1711 1712 offset = 0; 1713 num -= this_num; 1714 total_len += this_num; 1715 index++; 1716 } 1717 ra->inarg.offset = outarg->offset; 1718 ra->inarg.size = total_len; 1719 args->in_args[0].size = sizeof(ra->inarg); 1720 args->in_args[0].value = &ra->inarg; 1721 args->in_args[1].size = total_len; 1722 1723 err = fuse_simple_notify_reply(fm, args, outarg->notify_unique); 1724 if (err) 1725 fuse_retrieve_end(fm, args, err); 1726 1727 return err; 1728 } 1729 1730 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1731 struct fuse_copy_state *cs) 1732 { 1733 struct fuse_notify_retrieve_out outarg; 1734 struct fuse_mount *fm; 1735 struct inode *inode; 1736 u64 nodeid; 1737 int err; 1738 1739 err = -EINVAL; 1740 if (size != sizeof(outarg)) 1741 goto copy_finish; 1742 1743 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1744 if (err) 1745 goto copy_finish; 1746 1747 fuse_copy_finish(cs); 1748 1749 down_read(&fc->killsb); 1750 err = -ENOENT; 1751 nodeid = outarg.nodeid; 1752 1753 inode = fuse_ilookup(fc, nodeid, &fm); 1754 if (inode) { 1755 err = fuse_retrieve(fm, inode, &outarg); 1756 iput(inode); 1757 } 1758 up_read(&fc->killsb); 1759 1760 return err; 1761 1762 copy_finish: 1763 fuse_copy_finish(cs); 1764 return err; 1765 } 1766 1767 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1768 unsigned int size, struct fuse_copy_state *cs) 1769 { 1770 /* Don't try to move pages (yet) */ 1771 cs->move_pages = 0; 1772 1773 switch (code) { 1774 case FUSE_NOTIFY_POLL: 1775 return fuse_notify_poll(fc, size, cs); 1776 1777 case FUSE_NOTIFY_INVAL_INODE: 1778 return fuse_notify_inval_inode(fc, size, cs); 1779 1780 case FUSE_NOTIFY_INVAL_ENTRY: 1781 return fuse_notify_inval_entry(fc, size, cs); 1782 1783 case FUSE_NOTIFY_STORE: 1784 return fuse_notify_store(fc, size, cs); 1785 1786 case FUSE_NOTIFY_RETRIEVE: 1787 return fuse_notify_retrieve(fc, size, cs); 1788 1789 case FUSE_NOTIFY_DELETE: 1790 return fuse_notify_delete(fc, size, cs); 1791 1792 default: 1793 fuse_copy_finish(cs); 1794 return -EINVAL; 1795 } 1796 } 1797 1798 /* Look up request on processing list by unique ID */ 1799 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1800 { 1801 unsigned int hash = fuse_req_hash(unique); 1802 struct fuse_req *req; 1803 1804 list_for_each_entry(req, &fpq->processing[hash], list) { 1805 if (req->in.h.unique == unique) 1806 return req; 1807 } 1808 return NULL; 1809 } 1810 1811 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, 1812 unsigned nbytes) 1813 { 1814 unsigned reqsize = sizeof(struct fuse_out_header); 1815 1816 reqsize += fuse_len_args(args->out_numargs, args->out_args); 1817 1818 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar)) 1819 return -EINVAL; 1820 else if (reqsize > nbytes) { 1821 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1]; 1822 unsigned diffsize = reqsize - nbytes; 1823 1824 if (diffsize > lastarg->size) 1825 return -EINVAL; 1826 lastarg->size -= diffsize; 1827 } 1828 return fuse_copy_args(cs, args->out_numargs, args->out_pages, 1829 args->out_args, args->page_zeroing); 1830 } 1831 1832 /* 1833 * Write a single reply to a request. First the header is copied from 1834 * the write buffer. The request is then searched on the processing 1835 * list by the unique ID found in the header. If found, then remove 1836 * it from the list and copy the rest of the buffer to the request. 1837 * The request is finished by calling fuse_request_end(). 1838 */ 1839 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1840 struct fuse_copy_state *cs, size_t nbytes) 1841 { 1842 int err; 1843 struct fuse_conn *fc = fud->fc; 1844 struct fuse_pqueue *fpq = &fud->pq; 1845 struct fuse_req *req; 1846 struct fuse_out_header oh; 1847 1848 err = -EINVAL; 1849 if (nbytes < sizeof(struct fuse_out_header)) 1850 goto out; 1851 1852 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1853 if (err) 1854 goto copy_finish; 1855 1856 err = -EINVAL; 1857 if (oh.len != nbytes) 1858 goto copy_finish; 1859 1860 /* 1861 * Zero oh.unique indicates unsolicited notification message 1862 * and error contains notification code. 1863 */ 1864 if (!oh.unique) { 1865 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1866 goto out; 1867 } 1868 1869 err = -EINVAL; 1870 if (oh.error <= -512 || oh.error > 0) 1871 goto copy_finish; 1872 1873 spin_lock(&fpq->lock); 1874 req = NULL; 1875 if (fpq->connected) 1876 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT); 1877 1878 err = -ENOENT; 1879 if (!req) { 1880 spin_unlock(&fpq->lock); 1881 goto copy_finish; 1882 } 1883 1884 /* Is it an interrupt reply ID? */ 1885 if (oh.unique & FUSE_INT_REQ_BIT) { 1886 __fuse_get_request(req); 1887 spin_unlock(&fpq->lock); 1888 1889 err = 0; 1890 if (nbytes != sizeof(struct fuse_out_header)) 1891 err = -EINVAL; 1892 else if (oh.error == -ENOSYS) 1893 fc->no_interrupt = 1; 1894 else if (oh.error == -EAGAIN) 1895 err = queue_interrupt(req); 1896 1897 fuse_put_request(req); 1898 1899 goto copy_finish; 1900 } 1901 1902 clear_bit(FR_SENT, &req->flags); 1903 list_move(&req->list, &fpq->io); 1904 req->out.h = oh; 1905 set_bit(FR_LOCKED, &req->flags); 1906 spin_unlock(&fpq->lock); 1907 cs->req = req; 1908 if (!req->args->page_replace) 1909 cs->move_pages = 0; 1910 1911 if (oh.error) 1912 err = nbytes != sizeof(oh) ? -EINVAL : 0; 1913 else 1914 err = copy_out_args(cs, req->args, nbytes); 1915 fuse_copy_finish(cs); 1916 1917 spin_lock(&fpq->lock); 1918 clear_bit(FR_LOCKED, &req->flags); 1919 if (!fpq->connected) 1920 err = -ENOENT; 1921 else if (err) 1922 req->out.h.error = -EIO; 1923 if (!test_bit(FR_PRIVATE, &req->flags)) 1924 list_del_init(&req->list); 1925 spin_unlock(&fpq->lock); 1926 1927 fuse_request_end(req); 1928 out: 1929 return err ? err : nbytes; 1930 1931 copy_finish: 1932 fuse_copy_finish(cs); 1933 goto out; 1934 } 1935 1936 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1937 { 1938 struct fuse_copy_state cs; 1939 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1940 1941 if (!fud) 1942 return -EPERM; 1943 1944 if (!iter_is_iovec(from)) 1945 return -EINVAL; 1946 1947 fuse_copy_init(&cs, 0, from); 1948 1949 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1950 } 1951 1952 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1953 struct file *out, loff_t *ppos, 1954 size_t len, unsigned int flags) 1955 { 1956 unsigned int head, tail, mask, count; 1957 unsigned nbuf; 1958 unsigned idx; 1959 struct pipe_buffer *bufs; 1960 struct fuse_copy_state cs; 1961 struct fuse_dev *fud; 1962 size_t rem; 1963 ssize_t ret; 1964 1965 fud = fuse_get_dev(out); 1966 if (!fud) 1967 return -EPERM; 1968 1969 pipe_lock(pipe); 1970 1971 head = pipe->head; 1972 tail = pipe->tail; 1973 mask = pipe->ring_size - 1; 1974 count = head - tail; 1975 1976 bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL); 1977 if (!bufs) { 1978 pipe_unlock(pipe); 1979 return -ENOMEM; 1980 } 1981 1982 nbuf = 0; 1983 rem = 0; 1984 for (idx = tail; idx != head && rem < len; idx++) 1985 rem += pipe->bufs[idx & mask].len; 1986 1987 ret = -EINVAL; 1988 if (rem < len) 1989 goto out_free; 1990 1991 rem = len; 1992 while (rem) { 1993 struct pipe_buffer *ibuf; 1994 struct pipe_buffer *obuf; 1995 1996 if (WARN_ON(nbuf >= count || tail == head)) 1997 goto out_free; 1998 1999 ibuf = &pipe->bufs[tail & mask]; 2000 obuf = &bufs[nbuf]; 2001 2002 if (rem >= ibuf->len) { 2003 *obuf = *ibuf; 2004 ibuf->ops = NULL; 2005 tail++; 2006 pipe->tail = tail; 2007 } else { 2008 if (!pipe_buf_get(pipe, ibuf)) 2009 goto out_free; 2010 2011 *obuf = *ibuf; 2012 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 2013 obuf->len = rem; 2014 ibuf->offset += obuf->len; 2015 ibuf->len -= obuf->len; 2016 } 2017 nbuf++; 2018 rem -= obuf->len; 2019 } 2020 pipe_unlock(pipe); 2021 2022 fuse_copy_init(&cs, 0, NULL); 2023 cs.pipebufs = bufs; 2024 cs.nr_segs = nbuf; 2025 cs.pipe = pipe; 2026 2027 if (flags & SPLICE_F_MOVE) 2028 cs.move_pages = 1; 2029 2030 ret = fuse_dev_do_write(fud, &cs, len); 2031 2032 pipe_lock(pipe); 2033 out_free: 2034 for (idx = 0; idx < nbuf; idx++) 2035 pipe_buf_release(pipe, &bufs[idx]); 2036 pipe_unlock(pipe); 2037 2038 kvfree(bufs); 2039 return ret; 2040 } 2041 2042 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait) 2043 { 2044 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 2045 struct fuse_iqueue *fiq; 2046 struct fuse_dev *fud = fuse_get_dev(file); 2047 2048 if (!fud) 2049 return EPOLLERR; 2050 2051 fiq = &fud->fc->iq; 2052 poll_wait(file, &fiq->waitq, wait); 2053 2054 spin_lock(&fiq->lock); 2055 if (!fiq->connected) 2056 mask = EPOLLERR; 2057 else if (request_pending(fiq)) 2058 mask |= EPOLLIN | EPOLLRDNORM; 2059 spin_unlock(&fiq->lock); 2060 2061 return mask; 2062 } 2063 2064 /* Abort all requests on the given list (pending or processing) */ 2065 static void end_requests(struct list_head *head) 2066 { 2067 while (!list_empty(head)) { 2068 struct fuse_req *req; 2069 req = list_entry(head->next, struct fuse_req, list); 2070 req->out.h.error = -ECONNABORTED; 2071 clear_bit(FR_SENT, &req->flags); 2072 list_del_init(&req->list); 2073 fuse_request_end(req); 2074 } 2075 } 2076 2077 static void end_polls(struct fuse_conn *fc) 2078 { 2079 struct rb_node *p; 2080 2081 p = rb_first(&fc->polled_files); 2082 2083 while (p) { 2084 struct fuse_file *ff; 2085 ff = rb_entry(p, struct fuse_file, polled_node); 2086 wake_up_interruptible_all(&ff->poll_wait); 2087 2088 p = rb_next(p); 2089 } 2090 } 2091 2092 /* 2093 * Abort all requests. 2094 * 2095 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2096 * filesystem. 2097 * 2098 * The same effect is usually achievable through killing the filesystem daemon 2099 * and all users of the filesystem. The exception is the combination of an 2100 * asynchronous request and the tricky deadlock (see 2101 * Documentation/filesystems/fuse.rst). 2102 * 2103 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2104 * requests, they should be finished off immediately. Locked requests will be 2105 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2106 * requests. It is possible that some request will finish before we can. This 2107 * is OK, the request will in that case be removed from the list before we touch 2108 * it. 2109 */ 2110 void fuse_abort_conn(struct fuse_conn *fc) 2111 { 2112 struct fuse_iqueue *fiq = &fc->iq; 2113 2114 spin_lock(&fc->lock); 2115 if (fc->connected) { 2116 struct fuse_dev *fud; 2117 struct fuse_req *req, *next; 2118 LIST_HEAD(to_end); 2119 unsigned int i; 2120 2121 /* Background queuing checks fc->connected under bg_lock */ 2122 spin_lock(&fc->bg_lock); 2123 fc->connected = 0; 2124 spin_unlock(&fc->bg_lock); 2125 2126 fuse_set_initialized(fc); 2127 list_for_each_entry(fud, &fc->devices, entry) { 2128 struct fuse_pqueue *fpq = &fud->pq; 2129 2130 spin_lock(&fpq->lock); 2131 fpq->connected = 0; 2132 list_for_each_entry_safe(req, next, &fpq->io, list) { 2133 req->out.h.error = -ECONNABORTED; 2134 spin_lock(&req->waitq.lock); 2135 set_bit(FR_ABORTED, &req->flags); 2136 if (!test_bit(FR_LOCKED, &req->flags)) { 2137 set_bit(FR_PRIVATE, &req->flags); 2138 __fuse_get_request(req); 2139 list_move(&req->list, &to_end); 2140 } 2141 spin_unlock(&req->waitq.lock); 2142 } 2143 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2144 list_splice_tail_init(&fpq->processing[i], 2145 &to_end); 2146 spin_unlock(&fpq->lock); 2147 } 2148 spin_lock(&fc->bg_lock); 2149 fc->blocked = 0; 2150 fc->max_background = UINT_MAX; 2151 flush_bg_queue(fc); 2152 spin_unlock(&fc->bg_lock); 2153 2154 spin_lock(&fiq->lock); 2155 fiq->connected = 0; 2156 list_for_each_entry(req, &fiq->pending, list) 2157 clear_bit(FR_PENDING, &req->flags); 2158 list_splice_tail_init(&fiq->pending, &to_end); 2159 while (forget_pending(fiq)) 2160 kfree(fuse_dequeue_forget(fiq, 1, NULL)); 2161 wake_up_all(&fiq->waitq); 2162 spin_unlock(&fiq->lock); 2163 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2164 end_polls(fc); 2165 wake_up_all(&fc->blocked_waitq); 2166 spin_unlock(&fc->lock); 2167 2168 end_requests(&to_end); 2169 } else { 2170 spin_unlock(&fc->lock); 2171 } 2172 } 2173 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2174 2175 void fuse_wait_aborted(struct fuse_conn *fc) 2176 { 2177 /* matches implicit memory barrier in fuse_drop_waiting() */ 2178 smp_mb(); 2179 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0); 2180 } 2181 2182 int fuse_dev_release(struct inode *inode, struct file *file) 2183 { 2184 struct fuse_dev *fud = fuse_get_dev(file); 2185 2186 if (fud) { 2187 struct fuse_conn *fc = fud->fc; 2188 struct fuse_pqueue *fpq = &fud->pq; 2189 LIST_HEAD(to_end); 2190 unsigned int i; 2191 2192 spin_lock(&fpq->lock); 2193 WARN_ON(!list_empty(&fpq->io)); 2194 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2195 list_splice_init(&fpq->processing[i], &to_end); 2196 spin_unlock(&fpq->lock); 2197 2198 end_requests(&to_end); 2199 2200 /* Are we the last open device? */ 2201 if (atomic_dec_and_test(&fc->dev_count)) { 2202 WARN_ON(fc->iq.fasync != NULL); 2203 fuse_abort_conn(fc); 2204 } 2205 fuse_dev_free(fud); 2206 } 2207 return 0; 2208 } 2209 EXPORT_SYMBOL_GPL(fuse_dev_release); 2210 2211 static int fuse_dev_fasync(int fd, struct file *file, int on) 2212 { 2213 struct fuse_dev *fud = fuse_get_dev(file); 2214 2215 if (!fud) 2216 return -EPERM; 2217 2218 /* No locking - fasync_helper does its own locking */ 2219 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2220 } 2221 2222 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2223 { 2224 struct fuse_dev *fud; 2225 2226 if (new->private_data) 2227 return -EINVAL; 2228 2229 fud = fuse_dev_alloc_install(fc); 2230 if (!fud) 2231 return -ENOMEM; 2232 2233 new->private_data = fud; 2234 atomic_inc(&fc->dev_count); 2235 2236 return 0; 2237 } 2238 2239 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2240 unsigned long arg) 2241 { 2242 int res; 2243 int oldfd; 2244 struct fuse_dev *fud = NULL; 2245 2246 switch (cmd) { 2247 case FUSE_DEV_IOC_CLONE: 2248 res = -EFAULT; 2249 if (!get_user(oldfd, (__u32 __user *)arg)) { 2250 struct file *old = fget(oldfd); 2251 2252 res = -EINVAL; 2253 if (old) { 2254 /* 2255 * Check against file->f_op because CUSE 2256 * uses the same ioctl handler. 2257 */ 2258 if (old->f_op == file->f_op && 2259 old->f_cred->user_ns == file->f_cred->user_ns) 2260 fud = fuse_get_dev(old); 2261 2262 if (fud) { 2263 mutex_lock(&fuse_mutex); 2264 res = fuse_device_clone(fud->fc, file); 2265 mutex_unlock(&fuse_mutex); 2266 } 2267 fput(old); 2268 } 2269 } 2270 break; 2271 default: 2272 res = -ENOTTY; 2273 break; 2274 } 2275 return res; 2276 } 2277 2278 const struct file_operations fuse_dev_operations = { 2279 .owner = THIS_MODULE, 2280 .open = fuse_dev_open, 2281 .llseek = no_llseek, 2282 .read_iter = fuse_dev_read, 2283 .splice_read = fuse_dev_splice_read, 2284 .write_iter = fuse_dev_write, 2285 .splice_write = fuse_dev_splice_write, 2286 .poll = fuse_dev_poll, 2287 .release = fuse_dev_release, 2288 .fasync = fuse_dev_fasync, 2289 .unlocked_ioctl = fuse_dev_ioctl, 2290 .compat_ioctl = compat_ptr_ioctl, 2291 }; 2292 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2293 2294 static struct miscdevice fuse_miscdevice = { 2295 .minor = FUSE_MINOR, 2296 .name = "fuse", 2297 .fops = &fuse_dev_operations, 2298 }; 2299 2300 int __init fuse_dev_init(void) 2301 { 2302 int err = -ENOMEM; 2303 fuse_req_cachep = kmem_cache_create("fuse_request", 2304 sizeof(struct fuse_req), 2305 0, 0, NULL); 2306 if (!fuse_req_cachep) 2307 goto out; 2308 2309 err = misc_register(&fuse_miscdevice); 2310 if (err) 2311 goto out_cache_clean; 2312 2313 return 0; 2314 2315 out_cache_clean: 2316 kmem_cache_destroy(fuse_req_cachep); 2317 out: 2318 return err; 2319 } 2320 2321 void fuse_dev_cleanup(void) 2322 { 2323 misc_deregister(&fuse_miscdevice); 2324 kmem_cache_destroy(fuse_req_cachep); 2325 } 2326