1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/poll.h> 14 #include <linux/sched/signal.h> 15 #include <linux/uio.h> 16 #include <linux/miscdevice.h> 17 #include <linux/pagemap.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/pipe_fs_i.h> 21 #include <linux/swap.h> 22 #include <linux/splice.h> 23 #include <linux/sched.h> 24 25 MODULE_ALIAS_MISCDEV(FUSE_MINOR); 26 MODULE_ALIAS("devname:fuse"); 27 28 /* Ordinary requests have even IDs, while interrupts IDs are odd */ 29 #define FUSE_INT_REQ_BIT (1ULL << 0) 30 #define FUSE_REQ_ID_STEP (1ULL << 1) 31 32 static struct kmem_cache *fuse_req_cachep; 33 34 static struct fuse_dev *fuse_get_dev(struct file *file) 35 { 36 /* 37 * Lockless access is OK, because file->private data is set 38 * once during mount and is valid until the file is released. 39 */ 40 return READ_ONCE(file->private_data); 41 } 42 43 static void fuse_request_init(struct fuse_req *req) 44 { 45 INIT_LIST_HEAD(&req->list); 46 INIT_LIST_HEAD(&req->intr_entry); 47 init_waitqueue_head(&req->waitq); 48 refcount_set(&req->count, 1); 49 __set_bit(FR_PENDING, &req->flags); 50 } 51 52 static struct fuse_req *fuse_request_alloc(gfp_t flags) 53 { 54 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags); 55 if (req) 56 fuse_request_init(req); 57 58 return req; 59 } 60 61 static void fuse_request_free(struct fuse_req *req) 62 { 63 kmem_cache_free(fuse_req_cachep, req); 64 } 65 66 static void __fuse_get_request(struct fuse_req *req) 67 { 68 refcount_inc(&req->count); 69 } 70 71 /* Must be called with > 1 refcount */ 72 static void __fuse_put_request(struct fuse_req *req) 73 { 74 refcount_dec(&req->count); 75 } 76 77 void fuse_set_initialized(struct fuse_conn *fc) 78 { 79 /* Make sure stores before this are seen on another CPU */ 80 smp_wmb(); 81 fc->initialized = 1; 82 } 83 84 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 85 { 86 return !fc->initialized || (for_background && fc->blocked); 87 } 88 89 static void fuse_drop_waiting(struct fuse_conn *fc) 90 { 91 /* 92 * lockess check of fc->connected is okay, because atomic_dec_and_test() 93 * provides a memory barrier mached with the one in fuse_wait_aborted() 94 * to ensure no wake-up is missed. 95 */ 96 if (atomic_dec_and_test(&fc->num_waiting) && 97 !READ_ONCE(fc->connected)) { 98 /* wake up aborters */ 99 wake_up_all(&fc->blocked_waitq); 100 } 101 } 102 103 static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req); 104 105 static struct fuse_req *fuse_get_req(struct fuse_conn *fc, bool for_background) 106 { 107 struct fuse_req *req; 108 int err; 109 atomic_inc(&fc->num_waiting); 110 111 if (fuse_block_alloc(fc, for_background)) { 112 err = -EINTR; 113 if (wait_event_killable_exclusive(fc->blocked_waitq, 114 !fuse_block_alloc(fc, for_background))) 115 goto out; 116 } 117 /* Matches smp_wmb() in fuse_set_initialized() */ 118 smp_rmb(); 119 120 err = -ENOTCONN; 121 if (!fc->connected) 122 goto out; 123 124 err = -ECONNREFUSED; 125 if (fc->conn_error) 126 goto out; 127 128 req = fuse_request_alloc(GFP_KERNEL); 129 err = -ENOMEM; 130 if (!req) { 131 if (for_background) 132 wake_up(&fc->blocked_waitq); 133 goto out; 134 } 135 136 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid()); 137 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid()); 138 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 139 140 __set_bit(FR_WAITING, &req->flags); 141 if (for_background) 142 __set_bit(FR_BACKGROUND, &req->flags); 143 144 if (unlikely(req->in.h.uid == ((uid_t)-1) || 145 req->in.h.gid == ((gid_t)-1))) { 146 fuse_put_request(fc, req); 147 return ERR_PTR(-EOVERFLOW); 148 } 149 return req; 150 151 out: 152 fuse_drop_waiting(fc); 153 return ERR_PTR(err); 154 } 155 156 static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) 157 { 158 if (refcount_dec_and_test(&req->count)) { 159 if (test_bit(FR_BACKGROUND, &req->flags)) { 160 /* 161 * We get here in the unlikely case that a background 162 * request was allocated but not sent 163 */ 164 spin_lock(&fc->bg_lock); 165 if (!fc->blocked) 166 wake_up(&fc->blocked_waitq); 167 spin_unlock(&fc->bg_lock); 168 } 169 170 if (test_bit(FR_WAITING, &req->flags)) { 171 __clear_bit(FR_WAITING, &req->flags); 172 fuse_drop_waiting(fc); 173 } 174 175 fuse_request_free(req); 176 } 177 } 178 179 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args) 180 { 181 unsigned nbytes = 0; 182 unsigned i; 183 184 for (i = 0; i < numargs; i++) 185 nbytes += args[i].size; 186 187 return nbytes; 188 } 189 EXPORT_SYMBOL_GPL(fuse_len_args); 190 191 u64 fuse_get_unique(struct fuse_iqueue *fiq) 192 { 193 fiq->reqctr += FUSE_REQ_ID_STEP; 194 return fiq->reqctr; 195 } 196 EXPORT_SYMBOL_GPL(fuse_get_unique); 197 198 static unsigned int fuse_req_hash(u64 unique) 199 { 200 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS); 201 } 202 203 /** 204 * A new request is available, wake fiq->waitq 205 */ 206 static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq) 207 __releases(fiq->lock) 208 { 209 wake_up(&fiq->waitq); 210 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 211 spin_unlock(&fiq->lock); 212 } 213 214 const struct fuse_iqueue_ops fuse_dev_fiq_ops = { 215 .wake_forget_and_unlock = fuse_dev_wake_and_unlock, 216 .wake_interrupt_and_unlock = fuse_dev_wake_and_unlock, 217 .wake_pending_and_unlock = fuse_dev_wake_and_unlock, 218 }; 219 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops); 220 221 static void queue_request_and_unlock(struct fuse_iqueue *fiq, 222 struct fuse_req *req) 223 __releases(fiq->lock) 224 { 225 req->in.h.len = sizeof(struct fuse_in_header) + 226 fuse_len_args(req->args->in_numargs, 227 (struct fuse_arg *) req->args->in_args); 228 list_add_tail(&req->list, &fiq->pending); 229 fiq->ops->wake_pending_and_unlock(fiq); 230 } 231 232 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 233 u64 nodeid, u64 nlookup) 234 { 235 struct fuse_iqueue *fiq = &fc->iq; 236 237 forget->forget_one.nodeid = nodeid; 238 forget->forget_one.nlookup = nlookup; 239 240 spin_lock(&fiq->lock); 241 if (fiq->connected) { 242 fiq->forget_list_tail->next = forget; 243 fiq->forget_list_tail = forget; 244 fiq->ops->wake_forget_and_unlock(fiq); 245 } else { 246 kfree(forget); 247 spin_unlock(&fiq->lock); 248 } 249 } 250 251 static void flush_bg_queue(struct fuse_conn *fc) 252 { 253 struct fuse_iqueue *fiq = &fc->iq; 254 255 while (fc->active_background < fc->max_background && 256 !list_empty(&fc->bg_queue)) { 257 struct fuse_req *req; 258 259 req = list_first_entry(&fc->bg_queue, struct fuse_req, list); 260 list_del(&req->list); 261 fc->active_background++; 262 spin_lock(&fiq->lock); 263 req->in.h.unique = fuse_get_unique(fiq); 264 queue_request_and_unlock(fiq, req); 265 } 266 } 267 268 /* 269 * This function is called when a request is finished. Either a reply 270 * has arrived or it was aborted (and not yet sent) or some error 271 * occurred during communication with userspace, or the device file 272 * was closed. The requester thread is woken up (if still waiting), 273 * the 'end' callback is called if given, else the reference to the 274 * request is released 275 */ 276 void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req) 277 { 278 struct fuse_iqueue *fiq = &fc->iq; 279 bool async = req->args->end; 280 281 if (test_and_set_bit(FR_FINISHED, &req->flags)) 282 goto put_request; 283 /* 284 * test_and_set_bit() implies smp_mb() between bit 285 * changing and below intr_entry check. Pairs with 286 * smp_mb() from queue_interrupt(). 287 */ 288 if (!list_empty(&req->intr_entry)) { 289 spin_lock(&fiq->lock); 290 list_del_init(&req->intr_entry); 291 spin_unlock(&fiq->lock); 292 } 293 WARN_ON(test_bit(FR_PENDING, &req->flags)); 294 WARN_ON(test_bit(FR_SENT, &req->flags)); 295 if (test_bit(FR_BACKGROUND, &req->flags)) { 296 spin_lock(&fc->bg_lock); 297 clear_bit(FR_BACKGROUND, &req->flags); 298 if (fc->num_background == fc->max_background) { 299 fc->blocked = 0; 300 wake_up(&fc->blocked_waitq); 301 } else if (!fc->blocked) { 302 /* 303 * Wake up next waiter, if any. It's okay to use 304 * waitqueue_active(), as we've already synced up 305 * fc->blocked with waiters with the wake_up() call 306 * above. 307 */ 308 if (waitqueue_active(&fc->blocked_waitq)) 309 wake_up(&fc->blocked_waitq); 310 } 311 312 if (fc->num_background == fc->congestion_threshold && fc->sb) { 313 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 314 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 315 } 316 fc->num_background--; 317 fc->active_background--; 318 flush_bg_queue(fc); 319 spin_unlock(&fc->bg_lock); 320 } else { 321 /* Wake up waiter sleeping in request_wait_answer() */ 322 wake_up(&req->waitq); 323 } 324 325 if (async) 326 req->args->end(fc, req->args, req->out.h.error); 327 put_request: 328 fuse_put_request(fc, req); 329 } 330 EXPORT_SYMBOL_GPL(fuse_request_end); 331 332 static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) 333 { 334 spin_lock(&fiq->lock); 335 /* Check for we've sent request to interrupt this req */ 336 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) { 337 spin_unlock(&fiq->lock); 338 return -EINVAL; 339 } 340 341 if (list_empty(&req->intr_entry)) { 342 list_add_tail(&req->intr_entry, &fiq->interrupts); 343 /* 344 * Pairs with smp_mb() implied by test_and_set_bit() 345 * from request_end(). 346 */ 347 smp_mb(); 348 if (test_bit(FR_FINISHED, &req->flags)) { 349 list_del_init(&req->intr_entry); 350 spin_unlock(&fiq->lock); 351 return 0; 352 } 353 fiq->ops->wake_interrupt_and_unlock(fiq); 354 } else { 355 spin_unlock(&fiq->lock); 356 } 357 return 0; 358 } 359 360 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) 361 { 362 struct fuse_iqueue *fiq = &fc->iq; 363 int err; 364 365 if (!fc->no_interrupt) { 366 /* Any signal may interrupt this */ 367 err = wait_event_interruptible(req->waitq, 368 test_bit(FR_FINISHED, &req->flags)); 369 if (!err) 370 return; 371 372 set_bit(FR_INTERRUPTED, &req->flags); 373 /* matches barrier in fuse_dev_do_read() */ 374 smp_mb__after_atomic(); 375 if (test_bit(FR_SENT, &req->flags)) 376 queue_interrupt(fiq, req); 377 } 378 379 if (!test_bit(FR_FORCE, &req->flags)) { 380 /* Only fatal signals may interrupt this */ 381 err = wait_event_killable(req->waitq, 382 test_bit(FR_FINISHED, &req->flags)); 383 if (!err) 384 return; 385 386 spin_lock(&fiq->lock); 387 /* Request is not yet in userspace, bail out */ 388 if (test_bit(FR_PENDING, &req->flags)) { 389 list_del(&req->list); 390 spin_unlock(&fiq->lock); 391 __fuse_put_request(req); 392 req->out.h.error = -EINTR; 393 return; 394 } 395 spin_unlock(&fiq->lock); 396 } 397 398 /* 399 * Either request is already in userspace, or it was forced. 400 * Wait it out. 401 */ 402 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags)); 403 } 404 405 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 406 { 407 struct fuse_iqueue *fiq = &fc->iq; 408 409 BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); 410 spin_lock(&fiq->lock); 411 if (!fiq->connected) { 412 spin_unlock(&fiq->lock); 413 req->out.h.error = -ENOTCONN; 414 } else { 415 req->in.h.unique = fuse_get_unique(fiq); 416 /* acquire extra reference, since request is still needed 417 after fuse_request_end() */ 418 __fuse_get_request(req); 419 queue_request_and_unlock(fiq, req); 420 421 request_wait_answer(fc, req); 422 /* Pairs with smp_wmb() in fuse_request_end() */ 423 smp_rmb(); 424 } 425 } 426 427 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) 428 { 429 if (fc->minor < 4 && args->opcode == FUSE_STATFS) 430 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE; 431 432 if (fc->minor < 9) { 433 switch (args->opcode) { 434 case FUSE_LOOKUP: 435 case FUSE_CREATE: 436 case FUSE_MKNOD: 437 case FUSE_MKDIR: 438 case FUSE_SYMLINK: 439 case FUSE_LINK: 440 args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; 441 break; 442 case FUSE_GETATTR: 443 case FUSE_SETATTR: 444 args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; 445 break; 446 } 447 } 448 if (fc->minor < 12) { 449 switch (args->opcode) { 450 case FUSE_CREATE: 451 args->in_args[0].size = sizeof(struct fuse_open_in); 452 break; 453 case FUSE_MKNOD: 454 args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; 455 break; 456 } 457 } 458 } 459 460 static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req) 461 { 462 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid()); 463 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid()); 464 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 465 } 466 467 static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args) 468 { 469 req->in.h.opcode = args->opcode; 470 req->in.h.nodeid = args->nodeid; 471 req->args = args; 472 } 473 474 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) 475 { 476 struct fuse_req *req; 477 ssize_t ret; 478 479 if (args->force) { 480 atomic_inc(&fc->num_waiting); 481 req = fuse_request_alloc(GFP_KERNEL | __GFP_NOFAIL); 482 483 if (!args->nocreds) 484 fuse_force_creds(fc, req); 485 486 __set_bit(FR_WAITING, &req->flags); 487 __set_bit(FR_FORCE, &req->flags); 488 } else { 489 WARN_ON(args->nocreds); 490 req = fuse_get_req(fc, false); 491 if (IS_ERR(req)) 492 return PTR_ERR(req); 493 } 494 495 /* Needs to be done after fuse_get_req() so that fc->minor is valid */ 496 fuse_adjust_compat(fc, args); 497 fuse_args_to_req(req, args); 498 499 if (!args->noreply) 500 __set_bit(FR_ISREPLY, &req->flags); 501 __fuse_request_send(fc, req); 502 ret = req->out.h.error; 503 if (!ret && args->out_argvar) { 504 BUG_ON(args->out_numargs == 0); 505 ret = args->out_args[args->out_numargs - 1].size; 506 } 507 fuse_put_request(fc, req); 508 509 return ret; 510 } 511 512 static bool fuse_request_queue_background(struct fuse_conn *fc, 513 struct fuse_req *req) 514 { 515 bool queued = false; 516 517 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags)); 518 if (!test_bit(FR_WAITING, &req->flags)) { 519 __set_bit(FR_WAITING, &req->flags); 520 atomic_inc(&fc->num_waiting); 521 } 522 __set_bit(FR_ISREPLY, &req->flags); 523 spin_lock(&fc->bg_lock); 524 if (likely(fc->connected)) { 525 fc->num_background++; 526 if (fc->num_background == fc->max_background) 527 fc->blocked = 1; 528 if (fc->num_background == fc->congestion_threshold && fc->sb) { 529 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 530 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 531 } 532 list_add_tail(&req->list, &fc->bg_queue); 533 flush_bg_queue(fc); 534 queued = true; 535 } 536 spin_unlock(&fc->bg_lock); 537 538 return queued; 539 } 540 541 int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args, 542 gfp_t gfp_flags) 543 { 544 struct fuse_req *req; 545 546 if (args->force) { 547 WARN_ON(!args->nocreds); 548 req = fuse_request_alloc(gfp_flags); 549 if (!req) 550 return -ENOMEM; 551 __set_bit(FR_BACKGROUND, &req->flags); 552 } else { 553 WARN_ON(args->nocreds); 554 req = fuse_get_req(fc, true); 555 if (IS_ERR(req)) 556 return PTR_ERR(req); 557 } 558 559 fuse_args_to_req(req, args); 560 561 if (!fuse_request_queue_background(fc, req)) { 562 fuse_put_request(fc, req); 563 return -ENOTCONN; 564 } 565 566 return 0; 567 } 568 EXPORT_SYMBOL_GPL(fuse_simple_background); 569 570 static int fuse_simple_notify_reply(struct fuse_conn *fc, 571 struct fuse_args *args, u64 unique) 572 { 573 struct fuse_req *req; 574 struct fuse_iqueue *fiq = &fc->iq; 575 int err = 0; 576 577 req = fuse_get_req(fc, false); 578 if (IS_ERR(req)) 579 return PTR_ERR(req); 580 581 __clear_bit(FR_ISREPLY, &req->flags); 582 req->in.h.unique = unique; 583 584 fuse_args_to_req(req, args); 585 586 spin_lock(&fiq->lock); 587 if (fiq->connected) { 588 queue_request_and_unlock(fiq, req); 589 } else { 590 err = -ENODEV; 591 spin_unlock(&fiq->lock); 592 fuse_put_request(fc, req); 593 } 594 595 return err; 596 } 597 598 /* 599 * Lock the request. Up to the next unlock_request() there mustn't be 600 * anything that could cause a page-fault. If the request was already 601 * aborted bail out. 602 */ 603 static int lock_request(struct fuse_req *req) 604 { 605 int err = 0; 606 if (req) { 607 spin_lock(&req->waitq.lock); 608 if (test_bit(FR_ABORTED, &req->flags)) 609 err = -ENOENT; 610 else 611 set_bit(FR_LOCKED, &req->flags); 612 spin_unlock(&req->waitq.lock); 613 } 614 return err; 615 } 616 617 /* 618 * Unlock request. If it was aborted while locked, caller is responsible 619 * for unlocking and ending the request. 620 */ 621 static int unlock_request(struct fuse_req *req) 622 { 623 int err = 0; 624 if (req) { 625 spin_lock(&req->waitq.lock); 626 if (test_bit(FR_ABORTED, &req->flags)) 627 err = -ENOENT; 628 else 629 clear_bit(FR_LOCKED, &req->flags); 630 spin_unlock(&req->waitq.lock); 631 } 632 return err; 633 } 634 635 struct fuse_copy_state { 636 int write; 637 struct fuse_req *req; 638 struct iov_iter *iter; 639 struct pipe_buffer *pipebufs; 640 struct pipe_buffer *currbuf; 641 struct pipe_inode_info *pipe; 642 unsigned long nr_segs; 643 struct page *pg; 644 unsigned len; 645 unsigned offset; 646 unsigned move_pages:1; 647 }; 648 649 static void fuse_copy_init(struct fuse_copy_state *cs, int write, 650 struct iov_iter *iter) 651 { 652 memset(cs, 0, sizeof(*cs)); 653 cs->write = write; 654 cs->iter = iter; 655 } 656 657 /* Unmap and put previous page of userspace buffer */ 658 static void fuse_copy_finish(struct fuse_copy_state *cs) 659 { 660 if (cs->currbuf) { 661 struct pipe_buffer *buf = cs->currbuf; 662 663 if (cs->write) 664 buf->len = PAGE_SIZE - cs->len; 665 cs->currbuf = NULL; 666 } else if (cs->pg) { 667 if (cs->write) { 668 flush_dcache_page(cs->pg); 669 set_page_dirty_lock(cs->pg); 670 } 671 put_page(cs->pg); 672 } 673 cs->pg = NULL; 674 } 675 676 /* 677 * Get another pagefull of userspace buffer, and map it to kernel 678 * address space, and lock request 679 */ 680 static int fuse_copy_fill(struct fuse_copy_state *cs) 681 { 682 struct page *page; 683 int err; 684 685 err = unlock_request(cs->req); 686 if (err) 687 return err; 688 689 fuse_copy_finish(cs); 690 if (cs->pipebufs) { 691 struct pipe_buffer *buf = cs->pipebufs; 692 693 if (!cs->write) { 694 err = pipe_buf_confirm(cs->pipe, buf); 695 if (err) 696 return err; 697 698 BUG_ON(!cs->nr_segs); 699 cs->currbuf = buf; 700 cs->pg = buf->page; 701 cs->offset = buf->offset; 702 cs->len = buf->len; 703 cs->pipebufs++; 704 cs->nr_segs--; 705 } else { 706 if (cs->nr_segs == cs->pipe->buffers) 707 return -EIO; 708 709 page = alloc_page(GFP_HIGHUSER); 710 if (!page) 711 return -ENOMEM; 712 713 buf->page = page; 714 buf->offset = 0; 715 buf->len = 0; 716 717 cs->currbuf = buf; 718 cs->pg = page; 719 cs->offset = 0; 720 cs->len = PAGE_SIZE; 721 cs->pipebufs++; 722 cs->nr_segs++; 723 } 724 } else { 725 size_t off; 726 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off); 727 if (err < 0) 728 return err; 729 BUG_ON(!err); 730 cs->len = err; 731 cs->offset = off; 732 cs->pg = page; 733 iov_iter_advance(cs->iter, err); 734 } 735 736 return lock_request(cs->req); 737 } 738 739 /* Do as much copy to/from userspace buffer as we can */ 740 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 741 { 742 unsigned ncpy = min(*size, cs->len); 743 if (val) { 744 void *pgaddr = kmap_atomic(cs->pg); 745 void *buf = pgaddr + cs->offset; 746 747 if (cs->write) 748 memcpy(buf, *val, ncpy); 749 else 750 memcpy(*val, buf, ncpy); 751 752 kunmap_atomic(pgaddr); 753 *val += ncpy; 754 } 755 *size -= ncpy; 756 cs->len -= ncpy; 757 cs->offset += ncpy; 758 return ncpy; 759 } 760 761 static int fuse_check_page(struct page *page) 762 { 763 if (page_mapcount(page) || 764 page->mapping != NULL || 765 page_count(page) != 1 || 766 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 767 ~(1 << PG_locked | 768 1 << PG_referenced | 769 1 << PG_uptodate | 770 1 << PG_lru | 771 1 << PG_active | 772 1 << PG_reclaim))) { 773 pr_warn("trying to steal weird page\n"); 774 pr_warn(" page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping); 775 return 1; 776 } 777 return 0; 778 } 779 780 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 781 { 782 int err; 783 struct page *oldpage = *pagep; 784 struct page *newpage; 785 struct pipe_buffer *buf = cs->pipebufs; 786 787 err = unlock_request(cs->req); 788 if (err) 789 return err; 790 791 fuse_copy_finish(cs); 792 793 err = pipe_buf_confirm(cs->pipe, buf); 794 if (err) 795 return err; 796 797 BUG_ON(!cs->nr_segs); 798 cs->currbuf = buf; 799 cs->len = buf->len; 800 cs->pipebufs++; 801 cs->nr_segs--; 802 803 if (cs->len != PAGE_SIZE) 804 goto out_fallback; 805 806 if (pipe_buf_steal(cs->pipe, buf) != 0) 807 goto out_fallback; 808 809 newpage = buf->page; 810 811 if (!PageUptodate(newpage)) 812 SetPageUptodate(newpage); 813 814 ClearPageMappedToDisk(newpage); 815 816 if (fuse_check_page(newpage) != 0) 817 goto out_fallback_unlock; 818 819 /* 820 * This is a new and locked page, it shouldn't be mapped or 821 * have any special flags on it 822 */ 823 if (WARN_ON(page_mapped(oldpage))) 824 goto out_fallback_unlock; 825 if (WARN_ON(page_has_private(oldpage))) 826 goto out_fallback_unlock; 827 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 828 goto out_fallback_unlock; 829 if (WARN_ON(PageMlocked(oldpage))) 830 goto out_fallback_unlock; 831 832 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); 833 if (err) { 834 unlock_page(newpage); 835 return err; 836 } 837 838 get_page(newpage); 839 840 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 841 lru_cache_add_file(newpage); 842 843 err = 0; 844 spin_lock(&cs->req->waitq.lock); 845 if (test_bit(FR_ABORTED, &cs->req->flags)) 846 err = -ENOENT; 847 else 848 *pagep = newpage; 849 spin_unlock(&cs->req->waitq.lock); 850 851 if (err) { 852 unlock_page(newpage); 853 put_page(newpage); 854 return err; 855 } 856 857 unlock_page(oldpage); 858 put_page(oldpage); 859 cs->len = 0; 860 861 return 0; 862 863 out_fallback_unlock: 864 unlock_page(newpage); 865 out_fallback: 866 cs->pg = buf->page; 867 cs->offset = buf->offset; 868 869 err = lock_request(cs->req); 870 if (err) 871 return err; 872 873 return 1; 874 } 875 876 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 877 unsigned offset, unsigned count) 878 { 879 struct pipe_buffer *buf; 880 int err; 881 882 if (cs->nr_segs == cs->pipe->buffers) 883 return -EIO; 884 885 err = unlock_request(cs->req); 886 if (err) 887 return err; 888 889 fuse_copy_finish(cs); 890 891 buf = cs->pipebufs; 892 get_page(page); 893 buf->page = page; 894 buf->offset = offset; 895 buf->len = count; 896 897 cs->pipebufs++; 898 cs->nr_segs++; 899 cs->len = 0; 900 901 return 0; 902 } 903 904 /* 905 * Copy a page in the request to/from the userspace buffer. Must be 906 * done atomically 907 */ 908 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 909 unsigned offset, unsigned count, int zeroing) 910 { 911 int err; 912 struct page *page = *pagep; 913 914 if (page && zeroing && count < PAGE_SIZE) 915 clear_highpage(page); 916 917 while (count) { 918 if (cs->write && cs->pipebufs && page) { 919 return fuse_ref_page(cs, page, offset, count); 920 } else if (!cs->len) { 921 if (cs->move_pages && page && 922 offset == 0 && count == PAGE_SIZE) { 923 err = fuse_try_move_page(cs, pagep); 924 if (err <= 0) 925 return err; 926 } else { 927 err = fuse_copy_fill(cs); 928 if (err) 929 return err; 930 } 931 } 932 if (page) { 933 void *mapaddr = kmap_atomic(page); 934 void *buf = mapaddr + offset; 935 offset += fuse_copy_do(cs, &buf, &count); 936 kunmap_atomic(mapaddr); 937 } else 938 offset += fuse_copy_do(cs, NULL, &count); 939 } 940 if (page && !cs->write) 941 flush_dcache_page(page); 942 return 0; 943 } 944 945 /* Copy pages in the request to/from userspace buffer */ 946 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 947 int zeroing) 948 { 949 unsigned i; 950 struct fuse_req *req = cs->req; 951 struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args); 952 953 954 for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) { 955 int err; 956 unsigned int offset = ap->descs[i].offset; 957 unsigned int count = min(nbytes, ap->descs[i].length); 958 959 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing); 960 if (err) 961 return err; 962 963 nbytes -= count; 964 } 965 return 0; 966 } 967 968 /* Copy a single argument in the request to/from userspace buffer */ 969 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 970 { 971 while (size) { 972 if (!cs->len) { 973 int err = fuse_copy_fill(cs); 974 if (err) 975 return err; 976 } 977 fuse_copy_do(cs, &val, &size); 978 } 979 return 0; 980 } 981 982 /* Copy request arguments to/from userspace buffer */ 983 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 984 unsigned argpages, struct fuse_arg *args, 985 int zeroing) 986 { 987 int err = 0; 988 unsigned i; 989 990 for (i = 0; !err && i < numargs; i++) { 991 struct fuse_arg *arg = &args[i]; 992 if (i == numargs - 1 && argpages) 993 err = fuse_copy_pages(cs, arg->size, zeroing); 994 else 995 err = fuse_copy_one(cs, arg->value, arg->size); 996 } 997 return err; 998 } 999 1000 static int forget_pending(struct fuse_iqueue *fiq) 1001 { 1002 return fiq->forget_list_head.next != NULL; 1003 } 1004 1005 static int request_pending(struct fuse_iqueue *fiq) 1006 { 1007 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1008 forget_pending(fiq); 1009 } 1010 1011 /* 1012 * Transfer an interrupt request to userspace 1013 * 1014 * Unlike other requests this is assembled on demand, without a need 1015 * to allocate a separate fuse_req structure. 1016 * 1017 * Called with fiq->lock held, releases it 1018 */ 1019 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1020 struct fuse_copy_state *cs, 1021 size_t nbytes, struct fuse_req *req) 1022 __releases(fiq->lock) 1023 { 1024 struct fuse_in_header ih; 1025 struct fuse_interrupt_in arg; 1026 unsigned reqsize = sizeof(ih) + sizeof(arg); 1027 int err; 1028 1029 list_del_init(&req->intr_entry); 1030 memset(&ih, 0, sizeof(ih)); 1031 memset(&arg, 0, sizeof(arg)); 1032 ih.len = reqsize; 1033 ih.opcode = FUSE_INTERRUPT; 1034 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT); 1035 arg.unique = req->in.h.unique; 1036 1037 spin_unlock(&fiq->lock); 1038 if (nbytes < reqsize) 1039 return -EINVAL; 1040 1041 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1042 if (!err) 1043 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1044 fuse_copy_finish(cs); 1045 1046 return err ? err : reqsize; 1047 } 1048 1049 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq, 1050 unsigned int max, 1051 unsigned int *countp) 1052 { 1053 struct fuse_forget_link *head = fiq->forget_list_head.next; 1054 struct fuse_forget_link **newhead = &head; 1055 unsigned count; 1056 1057 for (count = 0; *newhead != NULL && count < max; count++) 1058 newhead = &(*newhead)->next; 1059 1060 fiq->forget_list_head.next = *newhead; 1061 *newhead = NULL; 1062 if (fiq->forget_list_head.next == NULL) 1063 fiq->forget_list_tail = &fiq->forget_list_head; 1064 1065 if (countp != NULL) 1066 *countp = count; 1067 1068 return head; 1069 } 1070 EXPORT_SYMBOL(fuse_dequeue_forget); 1071 1072 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1073 struct fuse_copy_state *cs, 1074 size_t nbytes) 1075 __releases(fiq->lock) 1076 { 1077 int err; 1078 struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL); 1079 struct fuse_forget_in arg = { 1080 .nlookup = forget->forget_one.nlookup, 1081 }; 1082 struct fuse_in_header ih = { 1083 .opcode = FUSE_FORGET, 1084 .nodeid = forget->forget_one.nodeid, 1085 .unique = fuse_get_unique(fiq), 1086 .len = sizeof(ih) + sizeof(arg), 1087 }; 1088 1089 spin_unlock(&fiq->lock); 1090 kfree(forget); 1091 if (nbytes < ih.len) 1092 return -EINVAL; 1093 1094 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1095 if (!err) 1096 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1097 fuse_copy_finish(cs); 1098 1099 if (err) 1100 return err; 1101 1102 return ih.len; 1103 } 1104 1105 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1106 struct fuse_copy_state *cs, size_t nbytes) 1107 __releases(fiq->lock) 1108 { 1109 int err; 1110 unsigned max_forgets; 1111 unsigned count; 1112 struct fuse_forget_link *head; 1113 struct fuse_batch_forget_in arg = { .count = 0 }; 1114 struct fuse_in_header ih = { 1115 .opcode = FUSE_BATCH_FORGET, 1116 .unique = fuse_get_unique(fiq), 1117 .len = sizeof(ih) + sizeof(arg), 1118 }; 1119 1120 if (nbytes < ih.len) { 1121 spin_unlock(&fiq->lock); 1122 return -EINVAL; 1123 } 1124 1125 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1126 head = fuse_dequeue_forget(fiq, max_forgets, &count); 1127 spin_unlock(&fiq->lock); 1128 1129 arg.count = count; 1130 ih.len += count * sizeof(struct fuse_forget_one); 1131 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1132 if (!err) 1133 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1134 1135 while (head) { 1136 struct fuse_forget_link *forget = head; 1137 1138 if (!err) { 1139 err = fuse_copy_one(cs, &forget->forget_one, 1140 sizeof(forget->forget_one)); 1141 } 1142 head = forget->next; 1143 kfree(forget); 1144 } 1145 1146 fuse_copy_finish(cs); 1147 1148 if (err) 1149 return err; 1150 1151 return ih.len; 1152 } 1153 1154 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1155 struct fuse_copy_state *cs, 1156 size_t nbytes) 1157 __releases(fiq->lock) 1158 { 1159 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1160 return fuse_read_single_forget(fiq, cs, nbytes); 1161 else 1162 return fuse_read_batch_forget(fiq, cs, nbytes); 1163 } 1164 1165 /* 1166 * Read a single request into the userspace filesystem's buffer. This 1167 * function waits until a request is available, then removes it from 1168 * the pending list and copies request data to userspace buffer. If 1169 * no reply is needed (FORGET) or request has been aborted or there 1170 * was an error during the copying then it's finished by calling 1171 * fuse_request_end(). Otherwise add it to the processing list, and set 1172 * the 'sent' flag. 1173 */ 1174 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1175 struct fuse_copy_state *cs, size_t nbytes) 1176 { 1177 ssize_t err; 1178 struct fuse_conn *fc = fud->fc; 1179 struct fuse_iqueue *fiq = &fc->iq; 1180 struct fuse_pqueue *fpq = &fud->pq; 1181 struct fuse_req *req; 1182 struct fuse_args *args; 1183 unsigned reqsize; 1184 unsigned int hash; 1185 1186 /* 1187 * Require sane minimum read buffer - that has capacity for fixed part 1188 * of any request header + negotiated max_write room for data. 1189 * 1190 * Historically libfuse reserves 4K for fixed header room, but e.g. 1191 * GlusterFS reserves only 80 bytes 1192 * 1193 * = `sizeof(fuse_in_header) + sizeof(fuse_write_in)` 1194 * 1195 * which is the absolute minimum any sane filesystem should be using 1196 * for header room. 1197 */ 1198 if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER, 1199 sizeof(struct fuse_in_header) + 1200 sizeof(struct fuse_write_in) + 1201 fc->max_write)) 1202 return -EINVAL; 1203 1204 restart: 1205 for (;;) { 1206 spin_lock(&fiq->lock); 1207 if (!fiq->connected || request_pending(fiq)) 1208 break; 1209 spin_unlock(&fiq->lock); 1210 1211 if (file->f_flags & O_NONBLOCK) 1212 return -EAGAIN; 1213 err = wait_event_interruptible_exclusive(fiq->waitq, 1214 !fiq->connected || request_pending(fiq)); 1215 if (err) 1216 return err; 1217 } 1218 1219 if (!fiq->connected) { 1220 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1221 goto err_unlock; 1222 } 1223 1224 if (!list_empty(&fiq->interrupts)) { 1225 req = list_entry(fiq->interrupts.next, struct fuse_req, 1226 intr_entry); 1227 return fuse_read_interrupt(fiq, cs, nbytes, req); 1228 } 1229 1230 if (forget_pending(fiq)) { 1231 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1232 return fuse_read_forget(fc, fiq, cs, nbytes); 1233 1234 if (fiq->forget_batch <= -8) 1235 fiq->forget_batch = 16; 1236 } 1237 1238 req = list_entry(fiq->pending.next, struct fuse_req, list); 1239 clear_bit(FR_PENDING, &req->flags); 1240 list_del_init(&req->list); 1241 spin_unlock(&fiq->lock); 1242 1243 args = req->args; 1244 reqsize = req->in.h.len; 1245 1246 /* If request is too large, reply with an error and restart the read */ 1247 if (nbytes < reqsize) { 1248 req->out.h.error = -EIO; 1249 /* SETXATTR is special, since it may contain too large data */ 1250 if (args->opcode == FUSE_SETXATTR) 1251 req->out.h.error = -E2BIG; 1252 fuse_request_end(fc, req); 1253 goto restart; 1254 } 1255 spin_lock(&fpq->lock); 1256 list_add(&req->list, &fpq->io); 1257 spin_unlock(&fpq->lock); 1258 cs->req = req; 1259 err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h)); 1260 if (!err) 1261 err = fuse_copy_args(cs, args->in_numargs, args->in_pages, 1262 (struct fuse_arg *) args->in_args, 0); 1263 fuse_copy_finish(cs); 1264 spin_lock(&fpq->lock); 1265 clear_bit(FR_LOCKED, &req->flags); 1266 if (!fpq->connected) { 1267 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1268 goto out_end; 1269 } 1270 if (err) { 1271 req->out.h.error = -EIO; 1272 goto out_end; 1273 } 1274 if (!test_bit(FR_ISREPLY, &req->flags)) { 1275 err = reqsize; 1276 goto out_end; 1277 } 1278 hash = fuse_req_hash(req->in.h.unique); 1279 list_move_tail(&req->list, &fpq->processing[hash]); 1280 __fuse_get_request(req); 1281 set_bit(FR_SENT, &req->flags); 1282 spin_unlock(&fpq->lock); 1283 /* matches barrier in request_wait_answer() */ 1284 smp_mb__after_atomic(); 1285 if (test_bit(FR_INTERRUPTED, &req->flags)) 1286 queue_interrupt(fiq, req); 1287 fuse_put_request(fc, req); 1288 1289 return reqsize; 1290 1291 out_end: 1292 if (!test_bit(FR_PRIVATE, &req->flags)) 1293 list_del_init(&req->list); 1294 spin_unlock(&fpq->lock); 1295 fuse_request_end(fc, req); 1296 return err; 1297 1298 err_unlock: 1299 spin_unlock(&fiq->lock); 1300 return err; 1301 } 1302 1303 static int fuse_dev_open(struct inode *inode, struct file *file) 1304 { 1305 /* 1306 * The fuse device's file's private_data is used to hold 1307 * the fuse_conn(ection) when it is mounted, and is used to 1308 * keep track of whether the file has been mounted already. 1309 */ 1310 file->private_data = NULL; 1311 return 0; 1312 } 1313 1314 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1315 { 1316 struct fuse_copy_state cs; 1317 struct file *file = iocb->ki_filp; 1318 struct fuse_dev *fud = fuse_get_dev(file); 1319 1320 if (!fud) 1321 return -EPERM; 1322 1323 if (!iter_is_iovec(to)) 1324 return -EINVAL; 1325 1326 fuse_copy_init(&cs, 1, to); 1327 1328 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1329 } 1330 1331 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1332 struct pipe_inode_info *pipe, 1333 size_t len, unsigned int flags) 1334 { 1335 int total, ret; 1336 int page_nr = 0; 1337 struct pipe_buffer *bufs; 1338 struct fuse_copy_state cs; 1339 struct fuse_dev *fud = fuse_get_dev(in); 1340 1341 if (!fud) 1342 return -EPERM; 1343 1344 bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer), 1345 GFP_KERNEL); 1346 if (!bufs) 1347 return -ENOMEM; 1348 1349 fuse_copy_init(&cs, 1, NULL); 1350 cs.pipebufs = bufs; 1351 cs.pipe = pipe; 1352 ret = fuse_dev_do_read(fud, in, &cs, len); 1353 if (ret < 0) 1354 goto out; 1355 1356 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) { 1357 ret = -EIO; 1358 goto out; 1359 } 1360 1361 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1362 /* 1363 * Need to be careful about this. Having buf->ops in module 1364 * code can Oops if the buffer persists after module unload. 1365 */ 1366 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1367 bufs[page_nr].flags = 0; 1368 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1369 if (unlikely(ret < 0)) 1370 break; 1371 } 1372 if (total) 1373 ret = total; 1374 out: 1375 for (; page_nr < cs.nr_segs; page_nr++) 1376 put_page(bufs[page_nr].page); 1377 1378 kvfree(bufs); 1379 return ret; 1380 } 1381 1382 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1383 struct fuse_copy_state *cs) 1384 { 1385 struct fuse_notify_poll_wakeup_out outarg; 1386 int err = -EINVAL; 1387 1388 if (size != sizeof(outarg)) 1389 goto err; 1390 1391 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1392 if (err) 1393 goto err; 1394 1395 fuse_copy_finish(cs); 1396 return fuse_notify_poll_wakeup(fc, &outarg); 1397 1398 err: 1399 fuse_copy_finish(cs); 1400 return err; 1401 } 1402 1403 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1404 struct fuse_copy_state *cs) 1405 { 1406 struct fuse_notify_inval_inode_out outarg; 1407 int err = -EINVAL; 1408 1409 if (size != sizeof(outarg)) 1410 goto err; 1411 1412 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1413 if (err) 1414 goto err; 1415 fuse_copy_finish(cs); 1416 1417 down_read(&fc->killsb); 1418 err = -ENOENT; 1419 if (fc->sb) { 1420 err = fuse_reverse_inval_inode(fc->sb, outarg.ino, 1421 outarg.off, outarg.len); 1422 } 1423 up_read(&fc->killsb); 1424 return err; 1425 1426 err: 1427 fuse_copy_finish(cs); 1428 return err; 1429 } 1430 1431 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1432 struct fuse_copy_state *cs) 1433 { 1434 struct fuse_notify_inval_entry_out outarg; 1435 int err = -ENOMEM; 1436 char *buf; 1437 struct qstr name; 1438 1439 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1440 if (!buf) 1441 goto err; 1442 1443 err = -EINVAL; 1444 if (size < sizeof(outarg)) 1445 goto err; 1446 1447 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1448 if (err) 1449 goto err; 1450 1451 err = -ENAMETOOLONG; 1452 if (outarg.namelen > FUSE_NAME_MAX) 1453 goto err; 1454 1455 err = -EINVAL; 1456 if (size != sizeof(outarg) + outarg.namelen + 1) 1457 goto err; 1458 1459 name.name = buf; 1460 name.len = outarg.namelen; 1461 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1462 if (err) 1463 goto err; 1464 fuse_copy_finish(cs); 1465 buf[outarg.namelen] = 0; 1466 1467 down_read(&fc->killsb); 1468 err = -ENOENT; 1469 if (fc->sb) 1470 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name); 1471 up_read(&fc->killsb); 1472 kfree(buf); 1473 return err; 1474 1475 err: 1476 kfree(buf); 1477 fuse_copy_finish(cs); 1478 return err; 1479 } 1480 1481 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1482 struct fuse_copy_state *cs) 1483 { 1484 struct fuse_notify_delete_out outarg; 1485 int err = -ENOMEM; 1486 char *buf; 1487 struct qstr name; 1488 1489 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1490 if (!buf) 1491 goto err; 1492 1493 err = -EINVAL; 1494 if (size < sizeof(outarg)) 1495 goto err; 1496 1497 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1498 if (err) 1499 goto err; 1500 1501 err = -ENAMETOOLONG; 1502 if (outarg.namelen > FUSE_NAME_MAX) 1503 goto err; 1504 1505 err = -EINVAL; 1506 if (size != sizeof(outarg) + outarg.namelen + 1) 1507 goto err; 1508 1509 name.name = buf; 1510 name.len = outarg.namelen; 1511 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1512 if (err) 1513 goto err; 1514 fuse_copy_finish(cs); 1515 buf[outarg.namelen] = 0; 1516 1517 down_read(&fc->killsb); 1518 err = -ENOENT; 1519 if (fc->sb) 1520 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 1521 outarg.child, &name); 1522 up_read(&fc->killsb); 1523 kfree(buf); 1524 return err; 1525 1526 err: 1527 kfree(buf); 1528 fuse_copy_finish(cs); 1529 return err; 1530 } 1531 1532 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1533 struct fuse_copy_state *cs) 1534 { 1535 struct fuse_notify_store_out outarg; 1536 struct inode *inode; 1537 struct address_space *mapping; 1538 u64 nodeid; 1539 int err; 1540 pgoff_t index; 1541 unsigned int offset; 1542 unsigned int num; 1543 loff_t file_size; 1544 loff_t end; 1545 1546 err = -EINVAL; 1547 if (size < sizeof(outarg)) 1548 goto out_finish; 1549 1550 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1551 if (err) 1552 goto out_finish; 1553 1554 err = -EINVAL; 1555 if (size - sizeof(outarg) != outarg.size) 1556 goto out_finish; 1557 1558 nodeid = outarg.nodeid; 1559 1560 down_read(&fc->killsb); 1561 1562 err = -ENOENT; 1563 if (!fc->sb) 1564 goto out_up_killsb; 1565 1566 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1567 if (!inode) 1568 goto out_up_killsb; 1569 1570 mapping = inode->i_mapping; 1571 index = outarg.offset >> PAGE_SHIFT; 1572 offset = outarg.offset & ~PAGE_MASK; 1573 file_size = i_size_read(inode); 1574 end = outarg.offset + outarg.size; 1575 if (end > file_size) { 1576 file_size = end; 1577 fuse_write_update_size(inode, file_size); 1578 } 1579 1580 num = outarg.size; 1581 while (num) { 1582 struct page *page; 1583 unsigned int this_num; 1584 1585 err = -ENOMEM; 1586 page = find_or_create_page(mapping, index, 1587 mapping_gfp_mask(mapping)); 1588 if (!page) 1589 goto out_iput; 1590 1591 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1592 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1593 if (!err && offset == 0 && 1594 (this_num == PAGE_SIZE || file_size == end)) 1595 SetPageUptodate(page); 1596 unlock_page(page); 1597 put_page(page); 1598 1599 if (err) 1600 goto out_iput; 1601 1602 num -= this_num; 1603 offset = 0; 1604 index++; 1605 } 1606 1607 err = 0; 1608 1609 out_iput: 1610 iput(inode); 1611 out_up_killsb: 1612 up_read(&fc->killsb); 1613 out_finish: 1614 fuse_copy_finish(cs); 1615 return err; 1616 } 1617 1618 struct fuse_retrieve_args { 1619 struct fuse_args_pages ap; 1620 struct fuse_notify_retrieve_in inarg; 1621 }; 1622 1623 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_args *args, 1624 int error) 1625 { 1626 struct fuse_retrieve_args *ra = 1627 container_of(args, typeof(*ra), ap.args); 1628 1629 release_pages(ra->ap.pages, ra->ap.num_pages); 1630 kfree(ra); 1631 } 1632 1633 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, 1634 struct fuse_notify_retrieve_out *outarg) 1635 { 1636 int err; 1637 struct address_space *mapping = inode->i_mapping; 1638 pgoff_t index; 1639 loff_t file_size; 1640 unsigned int num; 1641 unsigned int offset; 1642 size_t total_len = 0; 1643 unsigned int num_pages; 1644 struct fuse_retrieve_args *ra; 1645 size_t args_size = sizeof(*ra); 1646 struct fuse_args_pages *ap; 1647 struct fuse_args *args; 1648 1649 offset = outarg->offset & ~PAGE_MASK; 1650 file_size = i_size_read(inode); 1651 1652 num = min(outarg->size, fc->max_write); 1653 if (outarg->offset > file_size) 1654 num = 0; 1655 else if (outarg->offset + num > file_size) 1656 num = file_size - outarg->offset; 1657 1658 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1659 num_pages = min(num_pages, fc->max_pages); 1660 1661 args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0])); 1662 1663 ra = kzalloc(args_size, GFP_KERNEL); 1664 if (!ra) 1665 return -ENOMEM; 1666 1667 ap = &ra->ap; 1668 ap->pages = (void *) (ra + 1); 1669 ap->descs = (void *) (ap->pages + num_pages); 1670 1671 args = &ap->args; 1672 args->nodeid = outarg->nodeid; 1673 args->opcode = FUSE_NOTIFY_REPLY; 1674 args->in_numargs = 2; 1675 args->in_pages = true; 1676 args->end = fuse_retrieve_end; 1677 1678 index = outarg->offset >> PAGE_SHIFT; 1679 1680 while (num && ap->num_pages < num_pages) { 1681 struct page *page; 1682 unsigned int this_num; 1683 1684 page = find_get_page(mapping, index); 1685 if (!page) 1686 break; 1687 1688 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1689 ap->pages[ap->num_pages] = page; 1690 ap->descs[ap->num_pages].offset = offset; 1691 ap->descs[ap->num_pages].length = this_num; 1692 ap->num_pages++; 1693 1694 offset = 0; 1695 num -= this_num; 1696 total_len += this_num; 1697 index++; 1698 } 1699 ra->inarg.offset = outarg->offset; 1700 ra->inarg.size = total_len; 1701 args->in_args[0].size = sizeof(ra->inarg); 1702 args->in_args[0].value = &ra->inarg; 1703 args->in_args[1].size = total_len; 1704 1705 err = fuse_simple_notify_reply(fc, args, outarg->notify_unique); 1706 if (err) 1707 fuse_retrieve_end(fc, args, err); 1708 1709 return err; 1710 } 1711 1712 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1713 struct fuse_copy_state *cs) 1714 { 1715 struct fuse_notify_retrieve_out outarg; 1716 struct inode *inode; 1717 int err; 1718 1719 err = -EINVAL; 1720 if (size != sizeof(outarg)) 1721 goto copy_finish; 1722 1723 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1724 if (err) 1725 goto copy_finish; 1726 1727 fuse_copy_finish(cs); 1728 1729 down_read(&fc->killsb); 1730 err = -ENOENT; 1731 if (fc->sb) { 1732 u64 nodeid = outarg.nodeid; 1733 1734 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1735 if (inode) { 1736 err = fuse_retrieve(fc, inode, &outarg); 1737 iput(inode); 1738 } 1739 } 1740 up_read(&fc->killsb); 1741 1742 return err; 1743 1744 copy_finish: 1745 fuse_copy_finish(cs); 1746 return err; 1747 } 1748 1749 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1750 unsigned int size, struct fuse_copy_state *cs) 1751 { 1752 /* Don't try to move pages (yet) */ 1753 cs->move_pages = 0; 1754 1755 switch (code) { 1756 case FUSE_NOTIFY_POLL: 1757 return fuse_notify_poll(fc, size, cs); 1758 1759 case FUSE_NOTIFY_INVAL_INODE: 1760 return fuse_notify_inval_inode(fc, size, cs); 1761 1762 case FUSE_NOTIFY_INVAL_ENTRY: 1763 return fuse_notify_inval_entry(fc, size, cs); 1764 1765 case FUSE_NOTIFY_STORE: 1766 return fuse_notify_store(fc, size, cs); 1767 1768 case FUSE_NOTIFY_RETRIEVE: 1769 return fuse_notify_retrieve(fc, size, cs); 1770 1771 case FUSE_NOTIFY_DELETE: 1772 return fuse_notify_delete(fc, size, cs); 1773 1774 default: 1775 fuse_copy_finish(cs); 1776 return -EINVAL; 1777 } 1778 } 1779 1780 /* Look up request on processing list by unique ID */ 1781 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1782 { 1783 unsigned int hash = fuse_req_hash(unique); 1784 struct fuse_req *req; 1785 1786 list_for_each_entry(req, &fpq->processing[hash], list) { 1787 if (req->in.h.unique == unique) 1788 return req; 1789 } 1790 return NULL; 1791 } 1792 1793 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args, 1794 unsigned nbytes) 1795 { 1796 unsigned reqsize = sizeof(struct fuse_out_header); 1797 1798 reqsize += fuse_len_args(args->out_numargs, args->out_args); 1799 1800 if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar)) 1801 return -EINVAL; 1802 else if (reqsize > nbytes) { 1803 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1]; 1804 unsigned diffsize = reqsize - nbytes; 1805 1806 if (diffsize > lastarg->size) 1807 return -EINVAL; 1808 lastarg->size -= diffsize; 1809 } 1810 return fuse_copy_args(cs, args->out_numargs, args->out_pages, 1811 args->out_args, args->page_zeroing); 1812 } 1813 1814 /* 1815 * Write a single reply to a request. First the header is copied from 1816 * the write buffer. The request is then searched on the processing 1817 * list by the unique ID found in the header. If found, then remove 1818 * it from the list and copy the rest of the buffer to the request. 1819 * The request is finished by calling fuse_request_end(). 1820 */ 1821 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1822 struct fuse_copy_state *cs, size_t nbytes) 1823 { 1824 int err; 1825 struct fuse_conn *fc = fud->fc; 1826 struct fuse_pqueue *fpq = &fud->pq; 1827 struct fuse_req *req; 1828 struct fuse_out_header oh; 1829 1830 err = -EINVAL; 1831 if (nbytes < sizeof(struct fuse_out_header)) 1832 goto out; 1833 1834 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1835 if (err) 1836 goto copy_finish; 1837 1838 err = -EINVAL; 1839 if (oh.len != nbytes) 1840 goto copy_finish; 1841 1842 /* 1843 * Zero oh.unique indicates unsolicited notification message 1844 * and error contains notification code. 1845 */ 1846 if (!oh.unique) { 1847 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1848 goto out; 1849 } 1850 1851 err = -EINVAL; 1852 if (oh.error <= -1000 || oh.error > 0) 1853 goto copy_finish; 1854 1855 spin_lock(&fpq->lock); 1856 req = NULL; 1857 if (fpq->connected) 1858 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT); 1859 1860 err = -ENOENT; 1861 if (!req) { 1862 spin_unlock(&fpq->lock); 1863 goto copy_finish; 1864 } 1865 1866 /* Is it an interrupt reply ID? */ 1867 if (oh.unique & FUSE_INT_REQ_BIT) { 1868 __fuse_get_request(req); 1869 spin_unlock(&fpq->lock); 1870 1871 err = 0; 1872 if (nbytes != sizeof(struct fuse_out_header)) 1873 err = -EINVAL; 1874 else if (oh.error == -ENOSYS) 1875 fc->no_interrupt = 1; 1876 else if (oh.error == -EAGAIN) 1877 err = queue_interrupt(&fc->iq, req); 1878 1879 fuse_put_request(fc, req); 1880 1881 goto copy_finish; 1882 } 1883 1884 clear_bit(FR_SENT, &req->flags); 1885 list_move(&req->list, &fpq->io); 1886 req->out.h = oh; 1887 set_bit(FR_LOCKED, &req->flags); 1888 spin_unlock(&fpq->lock); 1889 cs->req = req; 1890 if (!req->args->page_replace) 1891 cs->move_pages = 0; 1892 1893 if (oh.error) 1894 err = nbytes != sizeof(oh) ? -EINVAL : 0; 1895 else 1896 err = copy_out_args(cs, req->args, nbytes); 1897 fuse_copy_finish(cs); 1898 1899 spin_lock(&fpq->lock); 1900 clear_bit(FR_LOCKED, &req->flags); 1901 if (!fpq->connected) 1902 err = -ENOENT; 1903 else if (err) 1904 req->out.h.error = -EIO; 1905 if (!test_bit(FR_PRIVATE, &req->flags)) 1906 list_del_init(&req->list); 1907 spin_unlock(&fpq->lock); 1908 1909 fuse_request_end(fc, req); 1910 out: 1911 return err ? err : nbytes; 1912 1913 copy_finish: 1914 fuse_copy_finish(cs); 1915 goto out; 1916 } 1917 1918 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1919 { 1920 struct fuse_copy_state cs; 1921 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1922 1923 if (!fud) 1924 return -EPERM; 1925 1926 if (!iter_is_iovec(from)) 1927 return -EINVAL; 1928 1929 fuse_copy_init(&cs, 0, from); 1930 1931 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1932 } 1933 1934 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1935 struct file *out, loff_t *ppos, 1936 size_t len, unsigned int flags) 1937 { 1938 unsigned nbuf; 1939 unsigned idx; 1940 struct pipe_buffer *bufs; 1941 struct fuse_copy_state cs; 1942 struct fuse_dev *fud; 1943 size_t rem; 1944 ssize_t ret; 1945 1946 fud = fuse_get_dev(out); 1947 if (!fud) 1948 return -EPERM; 1949 1950 pipe_lock(pipe); 1951 1952 bufs = kvmalloc_array(pipe->nrbufs, sizeof(struct pipe_buffer), 1953 GFP_KERNEL); 1954 if (!bufs) { 1955 pipe_unlock(pipe); 1956 return -ENOMEM; 1957 } 1958 1959 nbuf = 0; 1960 rem = 0; 1961 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) 1962 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; 1963 1964 ret = -EINVAL; 1965 if (rem < len) 1966 goto out_free; 1967 1968 rem = len; 1969 while (rem) { 1970 struct pipe_buffer *ibuf; 1971 struct pipe_buffer *obuf; 1972 1973 BUG_ON(nbuf >= pipe->buffers); 1974 BUG_ON(!pipe->nrbufs); 1975 ibuf = &pipe->bufs[pipe->curbuf]; 1976 obuf = &bufs[nbuf]; 1977 1978 if (rem >= ibuf->len) { 1979 *obuf = *ibuf; 1980 ibuf->ops = NULL; 1981 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 1982 pipe->nrbufs--; 1983 } else { 1984 if (!pipe_buf_get(pipe, ibuf)) 1985 goto out_free; 1986 1987 *obuf = *ibuf; 1988 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1989 obuf->len = rem; 1990 ibuf->offset += obuf->len; 1991 ibuf->len -= obuf->len; 1992 } 1993 nbuf++; 1994 rem -= obuf->len; 1995 } 1996 pipe_unlock(pipe); 1997 1998 fuse_copy_init(&cs, 0, NULL); 1999 cs.pipebufs = bufs; 2000 cs.nr_segs = nbuf; 2001 cs.pipe = pipe; 2002 2003 if (flags & SPLICE_F_MOVE) 2004 cs.move_pages = 1; 2005 2006 ret = fuse_dev_do_write(fud, &cs, len); 2007 2008 pipe_lock(pipe); 2009 out_free: 2010 for (idx = 0; idx < nbuf; idx++) 2011 pipe_buf_release(pipe, &bufs[idx]); 2012 pipe_unlock(pipe); 2013 2014 kvfree(bufs); 2015 return ret; 2016 } 2017 2018 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait) 2019 { 2020 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 2021 struct fuse_iqueue *fiq; 2022 struct fuse_dev *fud = fuse_get_dev(file); 2023 2024 if (!fud) 2025 return EPOLLERR; 2026 2027 fiq = &fud->fc->iq; 2028 poll_wait(file, &fiq->waitq, wait); 2029 2030 spin_lock(&fiq->lock); 2031 if (!fiq->connected) 2032 mask = EPOLLERR; 2033 else if (request_pending(fiq)) 2034 mask |= EPOLLIN | EPOLLRDNORM; 2035 spin_unlock(&fiq->lock); 2036 2037 return mask; 2038 } 2039 2040 /* Abort all requests on the given list (pending or processing) */ 2041 static void end_requests(struct fuse_conn *fc, struct list_head *head) 2042 { 2043 while (!list_empty(head)) { 2044 struct fuse_req *req; 2045 req = list_entry(head->next, struct fuse_req, list); 2046 req->out.h.error = -ECONNABORTED; 2047 clear_bit(FR_SENT, &req->flags); 2048 list_del_init(&req->list); 2049 fuse_request_end(fc, req); 2050 } 2051 } 2052 2053 static void end_polls(struct fuse_conn *fc) 2054 { 2055 struct rb_node *p; 2056 2057 p = rb_first(&fc->polled_files); 2058 2059 while (p) { 2060 struct fuse_file *ff; 2061 ff = rb_entry(p, struct fuse_file, polled_node); 2062 wake_up_interruptible_all(&ff->poll_wait); 2063 2064 p = rb_next(p); 2065 } 2066 } 2067 2068 /* 2069 * Abort all requests. 2070 * 2071 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2072 * filesystem. 2073 * 2074 * The same effect is usually achievable through killing the filesystem daemon 2075 * and all users of the filesystem. The exception is the combination of an 2076 * asynchronous request and the tricky deadlock (see 2077 * Documentation/filesystems/fuse.txt). 2078 * 2079 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2080 * requests, they should be finished off immediately. Locked requests will be 2081 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2082 * requests. It is possible that some request will finish before we can. This 2083 * is OK, the request will in that case be removed from the list before we touch 2084 * it. 2085 */ 2086 void fuse_abort_conn(struct fuse_conn *fc) 2087 { 2088 struct fuse_iqueue *fiq = &fc->iq; 2089 2090 spin_lock(&fc->lock); 2091 if (fc->connected) { 2092 struct fuse_dev *fud; 2093 struct fuse_req *req, *next; 2094 LIST_HEAD(to_end); 2095 unsigned int i; 2096 2097 /* Background queuing checks fc->connected under bg_lock */ 2098 spin_lock(&fc->bg_lock); 2099 fc->connected = 0; 2100 spin_unlock(&fc->bg_lock); 2101 2102 fuse_set_initialized(fc); 2103 list_for_each_entry(fud, &fc->devices, entry) { 2104 struct fuse_pqueue *fpq = &fud->pq; 2105 2106 spin_lock(&fpq->lock); 2107 fpq->connected = 0; 2108 list_for_each_entry_safe(req, next, &fpq->io, list) { 2109 req->out.h.error = -ECONNABORTED; 2110 spin_lock(&req->waitq.lock); 2111 set_bit(FR_ABORTED, &req->flags); 2112 if (!test_bit(FR_LOCKED, &req->flags)) { 2113 set_bit(FR_PRIVATE, &req->flags); 2114 __fuse_get_request(req); 2115 list_move(&req->list, &to_end); 2116 } 2117 spin_unlock(&req->waitq.lock); 2118 } 2119 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2120 list_splice_tail_init(&fpq->processing[i], 2121 &to_end); 2122 spin_unlock(&fpq->lock); 2123 } 2124 spin_lock(&fc->bg_lock); 2125 fc->blocked = 0; 2126 fc->max_background = UINT_MAX; 2127 flush_bg_queue(fc); 2128 spin_unlock(&fc->bg_lock); 2129 2130 spin_lock(&fiq->lock); 2131 fiq->connected = 0; 2132 list_for_each_entry(req, &fiq->pending, list) 2133 clear_bit(FR_PENDING, &req->flags); 2134 list_splice_tail_init(&fiq->pending, &to_end); 2135 while (forget_pending(fiq)) 2136 kfree(fuse_dequeue_forget(fiq, 1, NULL)); 2137 wake_up_all(&fiq->waitq); 2138 spin_unlock(&fiq->lock); 2139 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2140 end_polls(fc); 2141 wake_up_all(&fc->blocked_waitq); 2142 spin_unlock(&fc->lock); 2143 2144 end_requests(fc, &to_end); 2145 } else { 2146 spin_unlock(&fc->lock); 2147 } 2148 } 2149 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2150 2151 void fuse_wait_aborted(struct fuse_conn *fc) 2152 { 2153 /* matches implicit memory barrier in fuse_drop_waiting() */ 2154 smp_mb(); 2155 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0); 2156 } 2157 2158 int fuse_dev_release(struct inode *inode, struct file *file) 2159 { 2160 struct fuse_dev *fud = fuse_get_dev(file); 2161 2162 if (fud) { 2163 struct fuse_conn *fc = fud->fc; 2164 struct fuse_pqueue *fpq = &fud->pq; 2165 LIST_HEAD(to_end); 2166 unsigned int i; 2167 2168 spin_lock(&fpq->lock); 2169 WARN_ON(!list_empty(&fpq->io)); 2170 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2171 list_splice_init(&fpq->processing[i], &to_end); 2172 spin_unlock(&fpq->lock); 2173 2174 end_requests(fc, &to_end); 2175 2176 /* Are we the last open device? */ 2177 if (atomic_dec_and_test(&fc->dev_count)) { 2178 WARN_ON(fc->iq.fasync != NULL); 2179 fuse_abort_conn(fc); 2180 } 2181 fuse_dev_free(fud); 2182 } 2183 return 0; 2184 } 2185 EXPORT_SYMBOL_GPL(fuse_dev_release); 2186 2187 static int fuse_dev_fasync(int fd, struct file *file, int on) 2188 { 2189 struct fuse_dev *fud = fuse_get_dev(file); 2190 2191 if (!fud) 2192 return -EPERM; 2193 2194 /* No locking - fasync_helper does its own locking */ 2195 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2196 } 2197 2198 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2199 { 2200 struct fuse_dev *fud; 2201 2202 if (new->private_data) 2203 return -EINVAL; 2204 2205 fud = fuse_dev_alloc_install(fc); 2206 if (!fud) 2207 return -ENOMEM; 2208 2209 new->private_data = fud; 2210 atomic_inc(&fc->dev_count); 2211 2212 return 0; 2213 } 2214 2215 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2216 unsigned long arg) 2217 { 2218 int err = -ENOTTY; 2219 2220 if (cmd == FUSE_DEV_IOC_CLONE) { 2221 int oldfd; 2222 2223 err = -EFAULT; 2224 if (!get_user(oldfd, (__u32 __user *) arg)) { 2225 struct file *old = fget(oldfd); 2226 2227 err = -EINVAL; 2228 if (old) { 2229 struct fuse_dev *fud = NULL; 2230 2231 /* 2232 * Check against file->f_op because CUSE 2233 * uses the same ioctl handler. 2234 */ 2235 if (old->f_op == file->f_op && 2236 old->f_cred->user_ns == file->f_cred->user_ns) 2237 fud = fuse_get_dev(old); 2238 2239 if (fud) { 2240 mutex_lock(&fuse_mutex); 2241 err = fuse_device_clone(fud->fc, file); 2242 mutex_unlock(&fuse_mutex); 2243 } 2244 fput(old); 2245 } 2246 } 2247 } 2248 return err; 2249 } 2250 2251 const struct file_operations fuse_dev_operations = { 2252 .owner = THIS_MODULE, 2253 .open = fuse_dev_open, 2254 .llseek = no_llseek, 2255 .read_iter = fuse_dev_read, 2256 .splice_read = fuse_dev_splice_read, 2257 .write_iter = fuse_dev_write, 2258 .splice_write = fuse_dev_splice_write, 2259 .poll = fuse_dev_poll, 2260 .release = fuse_dev_release, 2261 .fasync = fuse_dev_fasync, 2262 .unlocked_ioctl = fuse_dev_ioctl, 2263 .compat_ioctl = fuse_dev_ioctl, 2264 }; 2265 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2266 2267 static struct miscdevice fuse_miscdevice = { 2268 .minor = FUSE_MINOR, 2269 .name = "fuse", 2270 .fops = &fuse_dev_operations, 2271 }; 2272 2273 int __init fuse_dev_init(void) 2274 { 2275 int err = -ENOMEM; 2276 fuse_req_cachep = kmem_cache_create("fuse_request", 2277 sizeof(struct fuse_req), 2278 0, 0, NULL); 2279 if (!fuse_req_cachep) 2280 goto out; 2281 2282 err = misc_register(&fuse_miscdevice); 2283 if (err) 2284 goto out_cache_clean; 2285 2286 return 0; 2287 2288 out_cache_clean: 2289 kmem_cache_destroy(fuse_req_cachep); 2290 out: 2291 return err; 2292 } 2293 2294 void fuse_dev_cleanup(void) 2295 { 2296 misc_deregister(&fuse_miscdevice); 2297 kmem_cache_destroy(fuse_req_cachep); 2298 } 2299