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/uio.h> 15 #include <linux/miscdevice.h> 16 #include <linux/pagemap.h> 17 #include <linux/file.h> 18 #include <linux/slab.h> 19 #include <linux/pipe_fs_i.h> 20 #include <linux/swap.h> 21 #include <linux/splice.h> 22 23 MODULE_ALIAS_MISCDEV(FUSE_MINOR); 24 MODULE_ALIAS("devname:fuse"); 25 26 static struct kmem_cache *fuse_req_cachep; 27 28 static struct fuse_dev *fuse_get_dev(struct file *file) 29 { 30 /* 31 * Lockless access is OK, because file->private data is set 32 * once during mount and is valid until the file is released. 33 */ 34 return ACCESS_ONCE(file->private_data); 35 } 36 37 static void fuse_request_init(struct fuse_req *req, struct page **pages, 38 struct fuse_page_desc *page_descs, 39 unsigned npages) 40 { 41 memset(req, 0, sizeof(*req)); 42 memset(pages, 0, sizeof(*pages) * npages); 43 memset(page_descs, 0, sizeof(*page_descs) * npages); 44 INIT_LIST_HEAD(&req->list); 45 INIT_LIST_HEAD(&req->intr_entry); 46 init_waitqueue_head(&req->waitq); 47 atomic_set(&req->count, 1); 48 req->pages = pages; 49 req->page_descs = page_descs; 50 req->max_pages = npages; 51 __set_bit(FR_PENDING, &req->flags); 52 } 53 54 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags) 55 { 56 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags); 57 if (req) { 58 struct page **pages; 59 struct fuse_page_desc *page_descs; 60 61 if (npages <= FUSE_REQ_INLINE_PAGES) { 62 pages = req->inline_pages; 63 page_descs = req->inline_page_descs; 64 } else { 65 pages = kmalloc(sizeof(struct page *) * npages, flags); 66 page_descs = kmalloc(sizeof(struct fuse_page_desc) * 67 npages, flags); 68 } 69 70 if (!pages || !page_descs) { 71 kfree(pages); 72 kfree(page_descs); 73 kmem_cache_free(fuse_req_cachep, req); 74 return NULL; 75 } 76 77 fuse_request_init(req, pages, page_descs, npages); 78 } 79 return req; 80 } 81 82 struct fuse_req *fuse_request_alloc(unsigned npages) 83 { 84 return __fuse_request_alloc(npages, GFP_KERNEL); 85 } 86 EXPORT_SYMBOL_GPL(fuse_request_alloc); 87 88 struct fuse_req *fuse_request_alloc_nofs(unsigned npages) 89 { 90 return __fuse_request_alloc(npages, GFP_NOFS); 91 } 92 93 void fuse_request_free(struct fuse_req *req) 94 { 95 if (req->pages != req->inline_pages) { 96 kfree(req->pages); 97 kfree(req->page_descs); 98 } 99 kmem_cache_free(fuse_req_cachep, req); 100 } 101 102 void __fuse_get_request(struct fuse_req *req) 103 { 104 atomic_inc(&req->count); 105 } 106 107 /* Must be called with > 1 refcount */ 108 static void __fuse_put_request(struct fuse_req *req) 109 { 110 BUG_ON(atomic_read(&req->count) < 2); 111 atomic_dec(&req->count); 112 } 113 114 static void fuse_req_init_context(struct fuse_req *req) 115 { 116 req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid()); 117 req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid()); 118 req->in.h.pid = current->pid; 119 } 120 121 void fuse_set_initialized(struct fuse_conn *fc) 122 { 123 /* Make sure stores before this are seen on another CPU */ 124 smp_wmb(); 125 fc->initialized = 1; 126 } 127 128 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 129 { 130 return !fc->initialized || (for_background && fc->blocked); 131 } 132 133 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages, 134 bool for_background) 135 { 136 struct fuse_req *req; 137 int err; 138 atomic_inc(&fc->num_waiting); 139 140 if (fuse_block_alloc(fc, for_background)) { 141 err = -EINTR; 142 if (wait_event_killable_exclusive(fc->blocked_waitq, 143 !fuse_block_alloc(fc, for_background))) 144 goto out; 145 } 146 /* Matches smp_wmb() in fuse_set_initialized() */ 147 smp_rmb(); 148 149 err = -ENOTCONN; 150 if (!fc->connected) 151 goto out; 152 153 err = -ECONNREFUSED; 154 if (fc->conn_error) 155 goto out; 156 157 req = fuse_request_alloc(npages); 158 err = -ENOMEM; 159 if (!req) { 160 if (for_background) 161 wake_up(&fc->blocked_waitq); 162 goto out; 163 } 164 165 fuse_req_init_context(req); 166 __set_bit(FR_WAITING, &req->flags); 167 if (for_background) 168 __set_bit(FR_BACKGROUND, &req->flags); 169 170 return req; 171 172 out: 173 atomic_dec(&fc->num_waiting); 174 return ERR_PTR(err); 175 } 176 177 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages) 178 { 179 return __fuse_get_req(fc, npages, false); 180 } 181 EXPORT_SYMBOL_GPL(fuse_get_req); 182 183 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc, 184 unsigned npages) 185 { 186 return __fuse_get_req(fc, npages, true); 187 } 188 EXPORT_SYMBOL_GPL(fuse_get_req_for_background); 189 190 /* 191 * Return request in fuse_file->reserved_req. However that may 192 * currently be in use. If that is the case, wait for it to become 193 * available. 194 */ 195 static struct fuse_req *get_reserved_req(struct fuse_conn *fc, 196 struct file *file) 197 { 198 struct fuse_req *req = NULL; 199 struct fuse_file *ff = file->private_data; 200 201 do { 202 wait_event(fc->reserved_req_waitq, ff->reserved_req); 203 spin_lock(&fc->lock); 204 if (ff->reserved_req) { 205 req = ff->reserved_req; 206 ff->reserved_req = NULL; 207 req->stolen_file = get_file(file); 208 } 209 spin_unlock(&fc->lock); 210 } while (!req); 211 212 return req; 213 } 214 215 /* 216 * Put stolen request back into fuse_file->reserved_req 217 */ 218 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req) 219 { 220 struct file *file = req->stolen_file; 221 struct fuse_file *ff = file->private_data; 222 223 spin_lock(&fc->lock); 224 fuse_request_init(req, req->pages, req->page_descs, req->max_pages); 225 BUG_ON(ff->reserved_req); 226 ff->reserved_req = req; 227 wake_up_all(&fc->reserved_req_waitq); 228 spin_unlock(&fc->lock); 229 fput(file); 230 } 231 232 /* 233 * Gets a requests for a file operation, always succeeds 234 * 235 * This is used for sending the FLUSH request, which must get to 236 * userspace, due to POSIX locks which may need to be unlocked. 237 * 238 * If allocation fails due to OOM, use the reserved request in 239 * fuse_file. 240 * 241 * This is very unlikely to deadlock accidentally, since the 242 * filesystem should not have it's own file open. If deadlock is 243 * intentional, it can still be broken by "aborting" the filesystem. 244 */ 245 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc, 246 struct file *file) 247 { 248 struct fuse_req *req; 249 250 atomic_inc(&fc->num_waiting); 251 wait_event(fc->blocked_waitq, fc->initialized); 252 /* Matches smp_wmb() in fuse_set_initialized() */ 253 smp_rmb(); 254 req = fuse_request_alloc(0); 255 if (!req) 256 req = get_reserved_req(fc, file); 257 258 fuse_req_init_context(req); 259 __set_bit(FR_WAITING, &req->flags); 260 __clear_bit(FR_BACKGROUND, &req->flags); 261 return req; 262 } 263 264 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) 265 { 266 if (atomic_dec_and_test(&req->count)) { 267 if (test_bit(FR_BACKGROUND, &req->flags)) { 268 /* 269 * We get here in the unlikely case that a background 270 * request was allocated but not sent 271 */ 272 spin_lock(&fc->lock); 273 if (!fc->blocked) 274 wake_up(&fc->blocked_waitq); 275 spin_unlock(&fc->lock); 276 } 277 278 if (test_bit(FR_WAITING, &req->flags)) { 279 __clear_bit(FR_WAITING, &req->flags); 280 atomic_dec(&fc->num_waiting); 281 } 282 283 if (req->stolen_file) 284 put_reserved_req(fc, req); 285 else 286 fuse_request_free(req); 287 } 288 } 289 EXPORT_SYMBOL_GPL(fuse_put_request); 290 291 static unsigned len_args(unsigned numargs, struct fuse_arg *args) 292 { 293 unsigned nbytes = 0; 294 unsigned i; 295 296 for (i = 0; i < numargs; i++) 297 nbytes += args[i].size; 298 299 return nbytes; 300 } 301 302 static u64 fuse_get_unique(struct fuse_iqueue *fiq) 303 { 304 return ++fiq->reqctr; 305 } 306 307 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req) 308 { 309 req->in.h.len = sizeof(struct fuse_in_header) + 310 len_args(req->in.numargs, (struct fuse_arg *) req->in.args); 311 list_add_tail(&req->list, &fiq->pending); 312 wake_up_locked(&fiq->waitq); 313 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 314 } 315 316 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 317 u64 nodeid, u64 nlookup) 318 { 319 struct fuse_iqueue *fiq = &fc->iq; 320 321 forget->forget_one.nodeid = nodeid; 322 forget->forget_one.nlookup = nlookup; 323 324 spin_lock(&fiq->waitq.lock); 325 if (fiq->connected) { 326 fiq->forget_list_tail->next = forget; 327 fiq->forget_list_tail = forget; 328 wake_up_locked(&fiq->waitq); 329 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 330 } else { 331 kfree(forget); 332 } 333 spin_unlock(&fiq->waitq.lock); 334 } 335 336 static void flush_bg_queue(struct fuse_conn *fc) 337 { 338 while (fc->active_background < fc->max_background && 339 !list_empty(&fc->bg_queue)) { 340 struct fuse_req *req; 341 struct fuse_iqueue *fiq = &fc->iq; 342 343 req = list_entry(fc->bg_queue.next, struct fuse_req, list); 344 list_del(&req->list); 345 fc->active_background++; 346 spin_lock(&fiq->waitq.lock); 347 req->in.h.unique = fuse_get_unique(fiq); 348 queue_request(fiq, req); 349 spin_unlock(&fiq->waitq.lock); 350 } 351 } 352 353 /* 354 * This function is called when a request is finished. Either a reply 355 * has arrived or it was aborted (and not yet sent) or some error 356 * occurred during communication with userspace, or the device file 357 * was closed. The requester thread is woken up (if still waiting), 358 * the 'end' callback is called if given, else the reference to the 359 * request is released 360 */ 361 static void request_end(struct fuse_conn *fc, struct fuse_req *req) 362 { 363 struct fuse_iqueue *fiq = &fc->iq; 364 365 if (test_and_set_bit(FR_FINISHED, &req->flags)) 366 return; 367 368 spin_lock(&fiq->waitq.lock); 369 list_del_init(&req->intr_entry); 370 spin_unlock(&fiq->waitq.lock); 371 WARN_ON(test_bit(FR_PENDING, &req->flags)); 372 WARN_ON(test_bit(FR_SENT, &req->flags)); 373 if (test_bit(FR_BACKGROUND, &req->flags)) { 374 spin_lock(&fc->lock); 375 clear_bit(FR_BACKGROUND, &req->flags); 376 if (fc->num_background == fc->max_background) 377 fc->blocked = 0; 378 379 /* Wake up next waiter, if any */ 380 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq)) 381 wake_up(&fc->blocked_waitq); 382 383 if (fc->num_background == fc->congestion_threshold && 384 fc->connected && fc->bdi_initialized) { 385 clear_bdi_congested(&fc->bdi, BLK_RW_SYNC); 386 clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC); 387 } 388 fc->num_background--; 389 fc->active_background--; 390 flush_bg_queue(fc); 391 spin_unlock(&fc->lock); 392 } 393 wake_up(&req->waitq); 394 if (req->end) 395 req->end(fc, req); 396 fuse_put_request(fc, req); 397 } 398 399 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) 400 { 401 spin_lock(&fiq->waitq.lock); 402 if (list_empty(&req->intr_entry)) { 403 list_add_tail(&req->intr_entry, &fiq->interrupts); 404 wake_up_locked(&fiq->waitq); 405 } 406 spin_unlock(&fiq->waitq.lock); 407 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 408 } 409 410 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) 411 { 412 struct fuse_iqueue *fiq = &fc->iq; 413 int err; 414 415 if (!fc->no_interrupt) { 416 /* Any signal may interrupt this */ 417 err = wait_event_interruptible(req->waitq, 418 test_bit(FR_FINISHED, &req->flags)); 419 if (!err) 420 return; 421 422 set_bit(FR_INTERRUPTED, &req->flags); 423 /* matches barrier in fuse_dev_do_read() */ 424 smp_mb__after_atomic(); 425 if (test_bit(FR_SENT, &req->flags)) 426 queue_interrupt(fiq, req); 427 } 428 429 if (!test_bit(FR_FORCE, &req->flags)) { 430 /* Only fatal signals may interrupt this */ 431 err = wait_event_killable(req->waitq, 432 test_bit(FR_FINISHED, &req->flags)); 433 if (!err) 434 return; 435 436 spin_lock(&fiq->waitq.lock); 437 /* Request is not yet in userspace, bail out */ 438 if (test_bit(FR_PENDING, &req->flags)) { 439 list_del(&req->list); 440 spin_unlock(&fiq->waitq.lock); 441 __fuse_put_request(req); 442 req->out.h.error = -EINTR; 443 return; 444 } 445 spin_unlock(&fiq->waitq.lock); 446 } 447 448 /* 449 * Either request is already in userspace, or it was forced. 450 * Wait it out. 451 */ 452 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags)); 453 } 454 455 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 456 { 457 struct fuse_iqueue *fiq = &fc->iq; 458 459 BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); 460 spin_lock(&fiq->waitq.lock); 461 if (!fiq->connected) { 462 spin_unlock(&fiq->waitq.lock); 463 req->out.h.error = -ENOTCONN; 464 } else { 465 req->in.h.unique = fuse_get_unique(fiq); 466 queue_request(fiq, req); 467 /* acquire extra reference, since request is still needed 468 after request_end() */ 469 __fuse_get_request(req); 470 spin_unlock(&fiq->waitq.lock); 471 472 request_wait_answer(fc, req); 473 /* Pairs with smp_wmb() in request_end() */ 474 smp_rmb(); 475 } 476 } 477 478 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 479 { 480 __set_bit(FR_ISREPLY, &req->flags); 481 if (!test_bit(FR_WAITING, &req->flags)) { 482 __set_bit(FR_WAITING, &req->flags); 483 atomic_inc(&fc->num_waiting); 484 } 485 __fuse_request_send(fc, req); 486 } 487 EXPORT_SYMBOL_GPL(fuse_request_send); 488 489 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) 490 { 491 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS) 492 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE; 493 494 if (fc->minor < 9) { 495 switch (args->in.h.opcode) { 496 case FUSE_LOOKUP: 497 case FUSE_CREATE: 498 case FUSE_MKNOD: 499 case FUSE_MKDIR: 500 case FUSE_SYMLINK: 501 case FUSE_LINK: 502 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; 503 break; 504 case FUSE_GETATTR: 505 case FUSE_SETATTR: 506 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; 507 break; 508 } 509 } 510 if (fc->minor < 12) { 511 switch (args->in.h.opcode) { 512 case FUSE_CREATE: 513 args->in.args[0].size = sizeof(struct fuse_open_in); 514 break; 515 case FUSE_MKNOD: 516 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; 517 break; 518 } 519 } 520 } 521 522 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) 523 { 524 struct fuse_req *req; 525 ssize_t ret; 526 527 req = fuse_get_req(fc, 0); 528 if (IS_ERR(req)) 529 return PTR_ERR(req); 530 531 /* Needs to be done after fuse_get_req() so that fc->minor is valid */ 532 fuse_adjust_compat(fc, args); 533 534 req->in.h.opcode = args->in.h.opcode; 535 req->in.h.nodeid = args->in.h.nodeid; 536 req->in.numargs = args->in.numargs; 537 memcpy(req->in.args, args->in.args, 538 args->in.numargs * sizeof(struct fuse_in_arg)); 539 req->out.argvar = args->out.argvar; 540 req->out.numargs = args->out.numargs; 541 memcpy(req->out.args, args->out.args, 542 args->out.numargs * sizeof(struct fuse_arg)); 543 fuse_request_send(fc, req); 544 ret = req->out.h.error; 545 if (!ret && args->out.argvar) { 546 BUG_ON(args->out.numargs != 1); 547 ret = req->out.args[0].size; 548 } 549 fuse_put_request(fc, req); 550 551 return ret; 552 } 553 554 /* 555 * Called under fc->lock 556 * 557 * fc->connected must have been checked previously 558 */ 559 void fuse_request_send_background_locked(struct fuse_conn *fc, 560 struct fuse_req *req) 561 { 562 BUG_ON(!test_bit(FR_BACKGROUND, &req->flags)); 563 if (!test_bit(FR_WAITING, &req->flags)) { 564 __set_bit(FR_WAITING, &req->flags); 565 atomic_inc(&fc->num_waiting); 566 } 567 __set_bit(FR_ISREPLY, &req->flags); 568 fc->num_background++; 569 if (fc->num_background == fc->max_background) 570 fc->blocked = 1; 571 if (fc->num_background == fc->congestion_threshold && 572 fc->bdi_initialized) { 573 set_bdi_congested(&fc->bdi, BLK_RW_SYNC); 574 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC); 575 } 576 list_add_tail(&req->list, &fc->bg_queue); 577 flush_bg_queue(fc); 578 } 579 580 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) 581 { 582 BUG_ON(!req->end); 583 spin_lock(&fc->lock); 584 if (fc->connected) { 585 fuse_request_send_background_locked(fc, req); 586 spin_unlock(&fc->lock); 587 } else { 588 spin_unlock(&fc->lock); 589 req->out.h.error = -ENOTCONN; 590 req->end(fc, req); 591 fuse_put_request(fc, req); 592 } 593 } 594 EXPORT_SYMBOL_GPL(fuse_request_send_background); 595 596 static int fuse_request_send_notify_reply(struct fuse_conn *fc, 597 struct fuse_req *req, u64 unique) 598 { 599 int err = -ENODEV; 600 struct fuse_iqueue *fiq = &fc->iq; 601 602 __clear_bit(FR_ISREPLY, &req->flags); 603 req->in.h.unique = unique; 604 spin_lock(&fiq->waitq.lock); 605 if (fiq->connected) { 606 queue_request(fiq, req); 607 err = 0; 608 } 609 spin_unlock(&fiq->waitq.lock); 610 611 return err; 612 } 613 614 void fuse_force_forget(struct file *file, u64 nodeid) 615 { 616 struct inode *inode = file_inode(file); 617 struct fuse_conn *fc = get_fuse_conn(inode); 618 struct fuse_req *req; 619 struct fuse_forget_in inarg; 620 621 memset(&inarg, 0, sizeof(inarg)); 622 inarg.nlookup = 1; 623 req = fuse_get_req_nofail_nopages(fc, file); 624 req->in.h.opcode = FUSE_FORGET; 625 req->in.h.nodeid = nodeid; 626 req->in.numargs = 1; 627 req->in.args[0].size = sizeof(inarg); 628 req->in.args[0].value = &inarg; 629 __clear_bit(FR_ISREPLY, &req->flags); 630 __fuse_request_send(fc, req); 631 /* ignore errors */ 632 fuse_put_request(fc, req); 633 } 634 635 /* 636 * Lock the request. Up to the next unlock_request() there mustn't be 637 * anything that could cause a page-fault. If the request was already 638 * aborted bail out. 639 */ 640 static int lock_request(struct fuse_req *req) 641 { 642 int err = 0; 643 if (req) { 644 spin_lock(&req->waitq.lock); 645 if (test_bit(FR_ABORTED, &req->flags)) 646 err = -ENOENT; 647 else 648 set_bit(FR_LOCKED, &req->flags); 649 spin_unlock(&req->waitq.lock); 650 } 651 return err; 652 } 653 654 /* 655 * Unlock request. If it was aborted while locked, caller is responsible 656 * for unlocking and ending the request. 657 */ 658 static int unlock_request(struct fuse_req *req) 659 { 660 int err = 0; 661 if (req) { 662 spin_lock(&req->waitq.lock); 663 if (test_bit(FR_ABORTED, &req->flags)) 664 err = -ENOENT; 665 else 666 clear_bit(FR_LOCKED, &req->flags); 667 spin_unlock(&req->waitq.lock); 668 } 669 return err; 670 } 671 672 struct fuse_copy_state { 673 int write; 674 struct fuse_req *req; 675 struct iov_iter *iter; 676 struct pipe_buffer *pipebufs; 677 struct pipe_buffer *currbuf; 678 struct pipe_inode_info *pipe; 679 unsigned long nr_segs; 680 struct page *pg; 681 unsigned len; 682 unsigned offset; 683 unsigned move_pages:1; 684 }; 685 686 static void fuse_copy_init(struct fuse_copy_state *cs, int write, 687 struct iov_iter *iter) 688 { 689 memset(cs, 0, sizeof(*cs)); 690 cs->write = write; 691 cs->iter = iter; 692 } 693 694 /* Unmap and put previous page of userspace buffer */ 695 static void fuse_copy_finish(struct fuse_copy_state *cs) 696 { 697 if (cs->currbuf) { 698 struct pipe_buffer *buf = cs->currbuf; 699 700 if (cs->write) 701 buf->len = PAGE_SIZE - cs->len; 702 cs->currbuf = NULL; 703 } else if (cs->pg) { 704 if (cs->write) { 705 flush_dcache_page(cs->pg); 706 set_page_dirty_lock(cs->pg); 707 } 708 put_page(cs->pg); 709 } 710 cs->pg = NULL; 711 } 712 713 /* 714 * Get another pagefull of userspace buffer, and map it to kernel 715 * address space, and lock request 716 */ 717 static int fuse_copy_fill(struct fuse_copy_state *cs) 718 { 719 struct page *page; 720 int err; 721 722 err = unlock_request(cs->req); 723 if (err) 724 return err; 725 726 fuse_copy_finish(cs); 727 if (cs->pipebufs) { 728 struct pipe_buffer *buf = cs->pipebufs; 729 730 if (!cs->write) { 731 err = buf->ops->confirm(cs->pipe, buf); 732 if (err) 733 return err; 734 735 BUG_ON(!cs->nr_segs); 736 cs->currbuf = buf; 737 cs->pg = buf->page; 738 cs->offset = buf->offset; 739 cs->len = buf->len; 740 cs->pipebufs++; 741 cs->nr_segs--; 742 } else { 743 if (cs->nr_segs == cs->pipe->buffers) 744 return -EIO; 745 746 page = alloc_page(GFP_HIGHUSER); 747 if (!page) 748 return -ENOMEM; 749 750 buf->page = page; 751 buf->offset = 0; 752 buf->len = 0; 753 754 cs->currbuf = buf; 755 cs->pg = page; 756 cs->offset = 0; 757 cs->len = PAGE_SIZE; 758 cs->pipebufs++; 759 cs->nr_segs++; 760 } 761 } else { 762 size_t off; 763 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off); 764 if (err < 0) 765 return err; 766 BUG_ON(!err); 767 cs->len = err; 768 cs->offset = off; 769 cs->pg = page; 770 iov_iter_advance(cs->iter, err); 771 } 772 773 return lock_request(cs->req); 774 } 775 776 /* Do as much copy to/from userspace buffer as we can */ 777 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 778 { 779 unsigned ncpy = min(*size, cs->len); 780 if (val) { 781 void *pgaddr = kmap_atomic(cs->pg); 782 void *buf = pgaddr + cs->offset; 783 784 if (cs->write) 785 memcpy(buf, *val, ncpy); 786 else 787 memcpy(*val, buf, ncpy); 788 789 kunmap_atomic(pgaddr); 790 *val += ncpy; 791 } 792 *size -= ncpy; 793 cs->len -= ncpy; 794 cs->offset += ncpy; 795 return ncpy; 796 } 797 798 static int fuse_check_page(struct page *page) 799 { 800 if (page_mapcount(page) || 801 page->mapping != NULL || 802 page_count(page) != 1 || 803 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 804 ~(1 << PG_locked | 805 1 << PG_referenced | 806 1 << PG_uptodate | 807 1 << PG_lru | 808 1 << PG_active | 809 1 << PG_reclaim))) { 810 printk(KERN_WARNING "fuse: trying to steal weird page\n"); 811 printk(KERN_WARNING " 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); 812 return 1; 813 } 814 return 0; 815 } 816 817 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 818 { 819 int err; 820 struct page *oldpage = *pagep; 821 struct page *newpage; 822 struct pipe_buffer *buf = cs->pipebufs; 823 824 err = unlock_request(cs->req); 825 if (err) 826 return err; 827 828 fuse_copy_finish(cs); 829 830 err = buf->ops->confirm(cs->pipe, buf); 831 if (err) 832 return err; 833 834 BUG_ON(!cs->nr_segs); 835 cs->currbuf = buf; 836 cs->len = buf->len; 837 cs->pipebufs++; 838 cs->nr_segs--; 839 840 if (cs->len != PAGE_SIZE) 841 goto out_fallback; 842 843 if (buf->ops->steal(cs->pipe, buf) != 0) 844 goto out_fallback; 845 846 newpage = buf->page; 847 848 if (!PageUptodate(newpage)) 849 SetPageUptodate(newpage); 850 851 ClearPageMappedToDisk(newpage); 852 853 if (fuse_check_page(newpage) != 0) 854 goto out_fallback_unlock; 855 856 /* 857 * This is a new and locked page, it shouldn't be mapped or 858 * have any special flags on it 859 */ 860 if (WARN_ON(page_mapped(oldpage))) 861 goto out_fallback_unlock; 862 if (WARN_ON(page_has_private(oldpage))) 863 goto out_fallback_unlock; 864 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 865 goto out_fallback_unlock; 866 if (WARN_ON(PageMlocked(oldpage))) 867 goto out_fallback_unlock; 868 869 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); 870 if (err) { 871 unlock_page(newpage); 872 return err; 873 } 874 875 get_page(newpage); 876 877 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 878 lru_cache_add_file(newpage); 879 880 err = 0; 881 spin_lock(&cs->req->waitq.lock); 882 if (test_bit(FR_ABORTED, &cs->req->flags)) 883 err = -ENOENT; 884 else 885 *pagep = newpage; 886 spin_unlock(&cs->req->waitq.lock); 887 888 if (err) { 889 unlock_page(newpage); 890 put_page(newpage); 891 return err; 892 } 893 894 unlock_page(oldpage); 895 put_page(oldpage); 896 cs->len = 0; 897 898 return 0; 899 900 out_fallback_unlock: 901 unlock_page(newpage); 902 out_fallback: 903 cs->pg = buf->page; 904 cs->offset = buf->offset; 905 906 err = lock_request(cs->req); 907 if (err) 908 return err; 909 910 return 1; 911 } 912 913 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 914 unsigned offset, unsigned count) 915 { 916 struct pipe_buffer *buf; 917 int err; 918 919 if (cs->nr_segs == cs->pipe->buffers) 920 return -EIO; 921 922 err = unlock_request(cs->req); 923 if (err) 924 return err; 925 926 fuse_copy_finish(cs); 927 928 buf = cs->pipebufs; 929 get_page(page); 930 buf->page = page; 931 buf->offset = offset; 932 buf->len = count; 933 934 cs->pipebufs++; 935 cs->nr_segs++; 936 cs->len = 0; 937 938 return 0; 939 } 940 941 /* 942 * Copy a page in the request to/from the userspace buffer. Must be 943 * done atomically 944 */ 945 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 946 unsigned offset, unsigned count, int zeroing) 947 { 948 int err; 949 struct page *page = *pagep; 950 951 if (page && zeroing && count < PAGE_SIZE) 952 clear_highpage(page); 953 954 while (count) { 955 if (cs->write && cs->pipebufs && page) { 956 return fuse_ref_page(cs, page, offset, count); 957 } else if (!cs->len) { 958 if (cs->move_pages && page && 959 offset == 0 && count == PAGE_SIZE) { 960 err = fuse_try_move_page(cs, pagep); 961 if (err <= 0) 962 return err; 963 } else { 964 err = fuse_copy_fill(cs); 965 if (err) 966 return err; 967 } 968 } 969 if (page) { 970 void *mapaddr = kmap_atomic(page); 971 void *buf = mapaddr + offset; 972 offset += fuse_copy_do(cs, &buf, &count); 973 kunmap_atomic(mapaddr); 974 } else 975 offset += fuse_copy_do(cs, NULL, &count); 976 } 977 if (page && !cs->write) 978 flush_dcache_page(page); 979 return 0; 980 } 981 982 /* Copy pages in the request to/from userspace buffer */ 983 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 984 int zeroing) 985 { 986 unsigned i; 987 struct fuse_req *req = cs->req; 988 989 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { 990 int err; 991 unsigned offset = req->page_descs[i].offset; 992 unsigned count = min(nbytes, req->page_descs[i].length); 993 994 err = fuse_copy_page(cs, &req->pages[i], offset, count, 995 zeroing); 996 if (err) 997 return err; 998 999 nbytes -= count; 1000 } 1001 return 0; 1002 } 1003 1004 /* Copy a single argument in the request to/from userspace buffer */ 1005 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 1006 { 1007 while (size) { 1008 if (!cs->len) { 1009 int err = fuse_copy_fill(cs); 1010 if (err) 1011 return err; 1012 } 1013 fuse_copy_do(cs, &val, &size); 1014 } 1015 return 0; 1016 } 1017 1018 /* Copy request arguments to/from userspace buffer */ 1019 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1020 unsigned argpages, struct fuse_arg *args, 1021 int zeroing) 1022 { 1023 int err = 0; 1024 unsigned i; 1025 1026 for (i = 0; !err && i < numargs; i++) { 1027 struct fuse_arg *arg = &args[i]; 1028 if (i == numargs - 1 && argpages) 1029 err = fuse_copy_pages(cs, arg->size, zeroing); 1030 else 1031 err = fuse_copy_one(cs, arg->value, arg->size); 1032 } 1033 return err; 1034 } 1035 1036 static int forget_pending(struct fuse_iqueue *fiq) 1037 { 1038 return fiq->forget_list_head.next != NULL; 1039 } 1040 1041 static int request_pending(struct fuse_iqueue *fiq) 1042 { 1043 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1044 forget_pending(fiq); 1045 } 1046 1047 /* 1048 * Transfer an interrupt request to userspace 1049 * 1050 * Unlike other requests this is assembled on demand, without a need 1051 * to allocate a separate fuse_req structure. 1052 * 1053 * Called with fiq->waitq.lock held, releases it 1054 */ 1055 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1056 struct fuse_copy_state *cs, 1057 size_t nbytes, struct fuse_req *req) 1058 __releases(fiq->waitq.lock) 1059 { 1060 struct fuse_in_header ih; 1061 struct fuse_interrupt_in arg; 1062 unsigned reqsize = sizeof(ih) + sizeof(arg); 1063 int err; 1064 1065 list_del_init(&req->intr_entry); 1066 req->intr_unique = fuse_get_unique(fiq); 1067 memset(&ih, 0, sizeof(ih)); 1068 memset(&arg, 0, sizeof(arg)); 1069 ih.len = reqsize; 1070 ih.opcode = FUSE_INTERRUPT; 1071 ih.unique = req->intr_unique; 1072 arg.unique = req->in.h.unique; 1073 1074 spin_unlock(&fiq->waitq.lock); 1075 if (nbytes < reqsize) 1076 return -EINVAL; 1077 1078 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1079 if (!err) 1080 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1081 fuse_copy_finish(cs); 1082 1083 return err ? err : reqsize; 1084 } 1085 1086 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq, 1087 unsigned max, 1088 unsigned *countp) 1089 { 1090 struct fuse_forget_link *head = fiq->forget_list_head.next; 1091 struct fuse_forget_link **newhead = &head; 1092 unsigned count; 1093 1094 for (count = 0; *newhead != NULL && count < max; count++) 1095 newhead = &(*newhead)->next; 1096 1097 fiq->forget_list_head.next = *newhead; 1098 *newhead = NULL; 1099 if (fiq->forget_list_head.next == NULL) 1100 fiq->forget_list_tail = &fiq->forget_list_head; 1101 1102 if (countp != NULL) 1103 *countp = count; 1104 1105 return head; 1106 } 1107 1108 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1109 struct fuse_copy_state *cs, 1110 size_t nbytes) 1111 __releases(fiq->waitq.lock) 1112 { 1113 int err; 1114 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL); 1115 struct fuse_forget_in arg = { 1116 .nlookup = forget->forget_one.nlookup, 1117 }; 1118 struct fuse_in_header ih = { 1119 .opcode = FUSE_FORGET, 1120 .nodeid = forget->forget_one.nodeid, 1121 .unique = fuse_get_unique(fiq), 1122 .len = sizeof(ih) + sizeof(arg), 1123 }; 1124 1125 spin_unlock(&fiq->waitq.lock); 1126 kfree(forget); 1127 if (nbytes < ih.len) 1128 return -EINVAL; 1129 1130 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1131 if (!err) 1132 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1133 fuse_copy_finish(cs); 1134 1135 if (err) 1136 return err; 1137 1138 return ih.len; 1139 } 1140 1141 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1142 struct fuse_copy_state *cs, size_t nbytes) 1143 __releases(fiq->waitq.lock) 1144 { 1145 int err; 1146 unsigned max_forgets; 1147 unsigned count; 1148 struct fuse_forget_link *head; 1149 struct fuse_batch_forget_in arg = { .count = 0 }; 1150 struct fuse_in_header ih = { 1151 .opcode = FUSE_BATCH_FORGET, 1152 .unique = fuse_get_unique(fiq), 1153 .len = sizeof(ih) + sizeof(arg), 1154 }; 1155 1156 if (nbytes < ih.len) { 1157 spin_unlock(&fiq->waitq.lock); 1158 return -EINVAL; 1159 } 1160 1161 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1162 head = dequeue_forget(fiq, max_forgets, &count); 1163 spin_unlock(&fiq->waitq.lock); 1164 1165 arg.count = count; 1166 ih.len += count * sizeof(struct fuse_forget_one); 1167 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1168 if (!err) 1169 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1170 1171 while (head) { 1172 struct fuse_forget_link *forget = head; 1173 1174 if (!err) { 1175 err = fuse_copy_one(cs, &forget->forget_one, 1176 sizeof(forget->forget_one)); 1177 } 1178 head = forget->next; 1179 kfree(forget); 1180 } 1181 1182 fuse_copy_finish(cs); 1183 1184 if (err) 1185 return err; 1186 1187 return ih.len; 1188 } 1189 1190 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1191 struct fuse_copy_state *cs, 1192 size_t nbytes) 1193 __releases(fiq->waitq.lock) 1194 { 1195 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1196 return fuse_read_single_forget(fiq, cs, nbytes); 1197 else 1198 return fuse_read_batch_forget(fiq, cs, nbytes); 1199 } 1200 1201 /* 1202 * Read a single request into the userspace filesystem's buffer. This 1203 * function waits until a request is available, then removes it from 1204 * the pending list and copies request data to userspace buffer. If 1205 * no reply is needed (FORGET) or request has been aborted or there 1206 * was an error during the copying then it's finished by calling 1207 * request_end(). Otherwise add it to the processing list, and set 1208 * the 'sent' flag. 1209 */ 1210 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1211 struct fuse_copy_state *cs, size_t nbytes) 1212 { 1213 ssize_t err; 1214 struct fuse_conn *fc = fud->fc; 1215 struct fuse_iqueue *fiq = &fc->iq; 1216 struct fuse_pqueue *fpq = &fud->pq; 1217 struct fuse_req *req; 1218 struct fuse_in *in; 1219 unsigned reqsize; 1220 1221 restart: 1222 spin_lock(&fiq->waitq.lock); 1223 err = -EAGAIN; 1224 if ((file->f_flags & O_NONBLOCK) && fiq->connected && 1225 !request_pending(fiq)) 1226 goto err_unlock; 1227 1228 err = wait_event_interruptible_exclusive_locked(fiq->waitq, 1229 !fiq->connected || request_pending(fiq)); 1230 if (err) 1231 goto err_unlock; 1232 1233 err = -ENODEV; 1234 if (!fiq->connected) 1235 goto err_unlock; 1236 1237 if (!list_empty(&fiq->interrupts)) { 1238 req = list_entry(fiq->interrupts.next, struct fuse_req, 1239 intr_entry); 1240 return fuse_read_interrupt(fiq, cs, nbytes, req); 1241 } 1242 1243 if (forget_pending(fiq)) { 1244 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1245 return fuse_read_forget(fc, fiq, cs, nbytes); 1246 1247 if (fiq->forget_batch <= -8) 1248 fiq->forget_batch = 16; 1249 } 1250 1251 req = list_entry(fiq->pending.next, struct fuse_req, list); 1252 clear_bit(FR_PENDING, &req->flags); 1253 list_del_init(&req->list); 1254 spin_unlock(&fiq->waitq.lock); 1255 1256 in = &req->in; 1257 reqsize = in->h.len; 1258 /* If request is too large, reply with an error and restart the read */ 1259 if (nbytes < reqsize) { 1260 req->out.h.error = -EIO; 1261 /* SETXATTR is special, since it may contain too large data */ 1262 if (in->h.opcode == FUSE_SETXATTR) 1263 req->out.h.error = -E2BIG; 1264 request_end(fc, req); 1265 goto restart; 1266 } 1267 spin_lock(&fpq->lock); 1268 list_add(&req->list, &fpq->io); 1269 spin_unlock(&fpq->lock); 1270 cs->req = req; 1271 err = fuse_copy_one(cs, &in->h, sizeof(in->h)); 1272 if (!err) 1273 err = fuse_copy_args(cs, in->numargs, in->argpages, 1274 (struct fuse_arg *) in->args, 0); 1275 fuse_copy_finish(cs); 1276 spin_lock(&fpq->lock); 1277 clear_bit(FR_LOCKED, &req->flags); 1278 if (!fpq->connected) { 1279 err = -ENODEV; 1280 goto out_end; 1281 } 1282 if (err) { 1283 req->out.h.error = -EIO; 1284 goto out_end; 1285 } 1286 if (!test_bit(FR_ISREPLY, &req->flags)) { 1287 err = reqsize; 1288 goto out_end; 1289 } 1290 list_move_tail(&req->list, &fpq->processing); 1291 spin_unlock(&fpq->lock); 1292 set_bit(FR_SENT, &req->flags); 1293 /* matches barrier in request_wait_answer() */ 1294 smp_mb__after_atomic(); 1295 if (test_bit(FR_INTERRUPTED, &req->flags)) 1296 queue_interrupt(fiq, req); 1297 1298 return reqsize; 1299 1300 out_end: 1301 if (!test_bit(FR_PRIVATE, &req->flags)) 1302 list_del_init(&req->list); 1303 spin_unlock(&fpq->lock); 1304 request_end(fc, req); 1305 return err; 1306 1307 err_unlock: 1308 spin_unlock(&fiq->waitq.lock); 1309 return err; 1310 } 1311 1312 static int fuse_dev_open(struct inode *inode, struct file *file) 1313 { 1314 /* 1315 * The fuse device's file's private_data is used to hold 1316 * the fuse_conn(ection) when it is mounted, and is used to 1317 * keep track of whether the file has been mounted already. 1318 */ 1319 file->private_data = NULL; 1320 return 0; 1321 } 1322 1323 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1324 { 1325 struct fuse_copy_state cs; 1326 struct file *file = iocb->ki_filp; 1327 struct fuse_dev *fud = fuse_get_dev(file); 1328 1329 if (!fud) 1330 return -EPERM; 1331 1332 if (!iter_is_iovec(to)) 1333 return -EINVAL; 1334 1335 fuse_copy_init(&cs, 1, to); 1336 1337 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1338 } 1339 1340 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1341 struct pipe_inode_info *pipe, 1342 size_t len, unsigned int flags) 1343 { 1344 int ret; 1345 int page_nr = 0; 1346 int do_wakeup = 0; 1347 struct pipe_buffer *bufs; 1348 struct fuse_copy_state cs; 1349 struct fuse_dev *fud = fuse_get_dev(in); 1350 1351 if (!fud) 1352 return -EPERM; 1353 1354 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1355 if (!bufs) 1356 return -ENOMEM; 1357 1358 fuse_copy_init(&cs, 1, NULL); 1359 cs.pipebufs = bufs; 1360 cs.pipe = pipe; 1361 ret = fuse_dev_do_read(fud, in, &cs, len); 1362 if (ret < 0) 1363 goto out; 1364 1365 ret = 0; 1366 pipe_lock(pipe); 1367 1368 if (!pipe->readers) { 1369 send_sig(SIGPIPE, current, 0); 1370 if (!ret) 1371 ret = -EPIPE; 1372 goto out_unlock; 1373 } 1374 1375 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) { 1376 ret = -EIO; 1377 goto out_unlock; 1378 } 1379 1380 while (page_nr < cs.nr_segs) { 1381 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 1382 struct pipe_buffer *buf = pipe->bufs + newbuf; 1383 1384 buf->page = bufs[page_nr].page; 1385 buf->offset = bufs[page_nr].offset; 1386 buf->len = bufs[page_nr].len; 1387 /* 1388 * Need to be careful about this. Having buf->ops in module 1389 * code can Oops if the buffer persists after module unload. 1390 */ 1391 buf->ops = &nosteal_pipe_buf_ops; 1392 1393 pipe->nrbufs++; 1394 page_nr++; 1395 ret += buf->len; 1396 1397 if (pipe->files) 1398 do_wakeup = 1; 1399 } 1400 1401 out_unlock: 1402 pipe_unlock(pipe); 1403 1404 if (do_wakeup) { 1405 smp_mb(); 1406 if (waitqueue_active(&pipe->wait)) 1407 wake_up_interruptible(&pipe->wait); 1408 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 1409 } 1410 1411 out: 1412 for (; page_nr < cs.nr_segs; page_nr++) 1413 put_page(bufs[page_nr].page); 1414 1415 kfree(bufs); 1416 return ret; 1417 } 1418 1419 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1420 struct fuse_copy_state *cs) 1421 { 1422 struct fuse_notify_poll_wakeup_out outarg; 1423 int err = -EINVAL; 1424 1425 if (size != sizeof(outarg)) 1426 goto err; 1427 1428 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1429 if (err) 1430 goto err; 1431 1432 fuse_copy_finish(cs); 1433 return fuse_notify_poll_wakeup(fc, &outarg); 1434 1435 err: 1436 fuse_copy_finish(cs); 1437 return err; 1438 } 1439 1440 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1441 struct fuse_copy_state *cs) 1442 { 1443 struct fuse_notify_inval_inode_out outarg; 1444 int err = -EINVAL; 1445 1446 if (size != sizeof(outarg)) 1447 goto err; 1448 1449 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1450 if (err) 1451 goto err; 1452 fuse_copy_finish(cs); 1453 1454 down_read(&fc->killsb); 1455 err = -ENOENT; 1456 if (fc->sb) { 1457 err = fuse_reverse_inval_inode(fc->sb, outarg.ino, 1458 outarg.off, outarg.len); 1459 } 1460 up_read(&fc->killsb); 1461 return err; 1462 1463 err: 1464 fuse_copy_finish(cs); 1465 return err; 1466 } 1467 1468 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1469 struct fuse_copy_state *cs) 1470 { 1471 struct fuse_notify_inval_entry_out outarg; 1472 int err = -ENOMEM; 1473 char *buf; 1474 struct qstr name; 1475 1476 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1477 if (!buf) 1478 goto err; 1479 1480 err = -EINVAL; 1481 if (size < sizeof(outarg)) 1482 goto err; 1483 1484 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1485 if (err) 1486 goto err; 1487 1488 err = -ENAMETOOLONG; 1489 if (outarg.namelen > FUSE_NAME_MAX) 1490 goto err; 1491 1492 err = -EINVAL; 1493 if (size != sizeof(outarg) + outarg.namelen + 1) 1494 goto err; 1495 1496 name.name = buf; 1497 name.len = outarg.namelen; 1498 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1499 if (err) 1500 goto err; 1501 fuse_copy_finish(cs); 1502 buf[outarg.namelen] = 0; 1503 1504 down_read(&fc->killsb); 1505 err = -ENOENT; 1506 if (fc->sb) 1507 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name); 1508 up_read(&fc->killsb); 1509 kfree(buf); 1510 return err; 1511 1512 err: 1513 kfree(buf); 1514 fuse_copy_finish(cs); 1515 return err; 1516 } 1517 1518 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1519 struct fuse_copy_state *cs) 1520 { 1521 struct fuse_notify_delete_out outarg; 1522 int err = -ENOMEM; 1523 char *buf; 1524 struct qstr name; 1525 1526 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1527 if (!buf) 1528 goto err; 1529 1530 err = -EINVAL; 1531 if (size < sizeof(outarg)) 1532 goto err; 1533 1534 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1535 if (err) 1536 goto err; 1537 1538 err = -ENAMETOOLONG; 1539 if (outarg.namelen > FUSE_NAME_MAX) 1540 goto err; 1541 1542 err = -EINVAL; 1543 if (size != sizeof(outarg) + outarg.namelen + 1) 1544 goto err; 1545 1546 name.name = buf; 1547 name.len = outarg.namelen; 1548 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1549 if (err) 1550 goto err; 1551 fuse_copy_finish(cs); 1552 buf[outarg.namelen] = 0; 1553 1554 down_read(&fc->killsb); 1555 err = -ENOENT; 1556 if (fc->sb) 1557 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 1558 outarg.child, &name); 1559 up_read(&fc->killsb); 1560 kfree(buf); 1561 return err; 1562 1563 err: 1564 kfree(buf); 1565 fuse_copy_finish(cs); 1566 return err; 1567 } 1568 1569 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1570 struct fuse_copy_state *cs) 1571 { 1572 struct fuse_notify_store_out outarg; 1573 struct inode *inode; 1574 struct address_space *mapping; 1575 u64 nodeid; 1576 int err; 1577 pgoff_t index; 1578 unsigned int offset; 1579 unsigned int num; 1580 loff_t file_size; 1581 loff_t end; 1582 1583 err = -EINVAL; 1584 if (size < sizeof(outarg)) 1585 goto out_finish; 1586 1587 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1588 if (err) 1589 goto out_finish; 1590 1591 err = -EINVAL; 1592 if (size - sizeof(outarg) != outarg.size) 1593 goto out_finish; 1594 1595 nodeid = outarg.nodeid; 1596 1597 down_read(&fc->killsb); 1598 1599 err = -ENOENT; 1600 if (!fc->sb) 1601 goto out_up_killsb; 1602 1603 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1604 if (!inode) 1605 goto out_up_killsb; 1606 1607 mapping = inode->i_mapping; 1608 index = outarg.offset >> PAGE_SHIFT; 1609 offset = outarg.offset & ~PAGE_MASK; 1610 file_size = i_size_read(inode); 1611 end = outarg.offset + outarg.size; 1612 if (end > file_size) { 1613 file_size = end; 1614 fuse_write_update_size(inode, file_size); 1615 } 1616 1617 num = outarg.size; 1618 while (num) { 1619 struct page *page; 1620 unsigned int this_num; 1621 1622 err = -ENOMEM; 1623 page = find_or_create_page(mapping, index, 1624 mapping_gfp_mask(mapping)); 1625 if (!page) 1626 goto out_iput; 1627 1628 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1629 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1630 if (!err && offset == 0 && 1631 (this_num == PAGE_SIZE || file_size == end)) 1632 SetPageUptodate(page); 1633 unlock_page(page); 1634 put_page(page); 1635 1636 if (err) 1637 goto out_iput; 1638 1639 num -= this_num; 1640 offset = 0; 1641 index++; 1642 } 1643 1644 err = 0; 1645 1646 out_iput: 1647 iput(inode); 1648 out_up_killsb: 1649 up_read(&fc->killsb); 1650 out_finish: 1651 fuse_copy_finish(cs); 1652 return err; 1653 } 1654 1655 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req) 1656 { 1657 release_pages(req->pages, req->num_pages, false); 1658 } 1659 1660 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, 1661 struct fuse_notify_retrieve_out *outarg) 1662 { 1663 int err; 1664 struct address_space *mapping = inode->i_mapping; 1665 struct fuse_req *req; 1666 pgoff_t index; 1667 loff_t file_size; 1668 unsigned int num; 1669 unsigned int offset; 1670 size_t total_len = 0; 1671 int num_pages; 1672 1673 offset = outarg->offset & ~PAGE_MASK; 1674 file_size = i_size_read(inode); 1675 1676 num = outarg->size; 1677 if (outarg->offset > file_size) 1678 num = 0; 1679 else if (outarg->offset + num > file_size) 1680 num = file_size - outarg->offset; 1681 1682 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1683 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ); 1684 1685 req = fuse_get_req(fc, num_pages); 1686 if (IS_ERR(req)) 1687 return PTR_ERR(req); 1688 1689 req->in.h.opcode = FUSE_NOTIFY_REPLY; 1690 req->in.h.nodeid = outarg->nodeid; 1691 req->in.numargs = 2; 1692 req->in.argpages = 1; 1693 req->page_descs[0].offset = offset; 1694 req->end = fuse_retrieve_end; 1695 1696 index = outarg->offset >> PAGE_SHIFT; 1697 1698 while (num && req->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 req->pages[req->num_pages] = page; 1708 req->page_descs[req->num_pages].length = this_num; 1709 req->num_pages++; 1710 1711 offset = 0; 1712 num -= this_num; 1713 total_len += this_num; 1714 index++; 1715 } 1716 req->misc.retrieve_in.offset = outarg->offset; 1717 req->misc.retrieve_in.size = total_len; 1718 req->in.args[0].size = sizeof(req->misc.retrieve_in); 1719 req->in.args[0].value = &req->misc.retrieve_in; 1720 req->in.args[1].size = total_len; 1721 1722 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique); 1723 if (err) 1724 fuse_retrieve_end(fc, req); 1725 1726 return err; 1727 } 1728 1729 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1730 struct fuse_copy_state *cs) 1731 { 1732 struct fuse_notify_retrieve_out outarg; 1733 struct inode *inode; 1734 int err; 1735 1736 err = -EINVAL; 1737 if (size != sizeof(outarg)) 1738 goto copy_finish; 1739 1740 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1741 if (err) 1742 goto copy_finish; 1743 1744 fuse_copy_finish(cs); 1745 1746 down_read(&fc->killsb); 1747 err = -ENOENT; 1748 if (fc->sb) { 1749 u64 nodeid = outarg.nodeid; 1750 1751 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1752 if (inode) { 1753 err = fuse_retrieve(fc, inode, &outarg); 1754 iput(inode); 1755 } 1756 } 1757 up_read(&fc->killsb); 1758 1759 return err; 1760 1761 copy_finish: 1762 fuse_copy_finish(cs); 1763 return err; 1764 } 1765 1766 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1767 unsigned int size, struct fuse_copy_state *cs) 1768 { 1769 /* Don't try to move pages (yet) */ 1770 cs->move_pages = 0; 1771 1772 switch (code) { 1773 case FUSE_NOTIFY_POLL: 1774 return fuse_notify_poll(fc, size, cs); 1775 1776 case FUSE_NOTIFY_INVAL_INODE: 1777 return fuse_notify_inval_inode(fc, size, cs); 1778 1779 case FUSE_NOTIFY_INVAL_ENTRY: 1780 return fuse_notify_inval_entry(fc, size, cs); 1781 1782 case FUSE_NOTIFY_STORE: 1783 return fuse_notify_store(fc, size, cs); 1784 1785 case FUSE_NOTIFY_RETRIEVE: 1786 return fuse_notify_retrieve(fc, size, cs); 1787 1788 case FUSE_NOTIFY_DELETE: 1789 return fuse_notify_delete(fc, size, cs); 1790 1791 default: 1792 fuse_copy_finish(cs); 1793 return -EINVAL; 1794 } 1795 } 1796 1797 /* Look up request on processing list by unique ID */ 1798 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1799 { 1800 struct fuse_req *req; 1801 1802 list_for_each_entry(req, &fpq->processing, list) { 1803 if (req->in.h.unique == unique || req->intr_unique == unique) 1804 return req; 1805 } 1806 return NULL; 1807 } 1808 1809 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, 1810 unsigned nbytes) 1811 { 1812 unsigned reqsize = sizeof(struct fuse_out_header); 1813 1814 if (out->h.error) 1815 return nbytes != reqsize ? -EINVAL : 0; 1816 1817 reqsize += len_args(out->numargs, out->args); 1818 1819 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) 1820 return -EINVAL; 1821 else if (reqsize > nbytes) { 1822 struct fuse_arg *lastarg = &out->args[out->numargs-1]; 1823 unsigned diffsize = reqsize - nbytes; 1824 if (diffsize > lastarg->size) 1825 return -EINVAL; 1826 lastarg->size -= diffsize; 1827 } 1828 return fuse_copy_args(cs, out->numargs, out->argpages, out->args, 1829 out->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 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 if (nbytes < sizeof(struct fuse_out_header)) 1849 return -EINVAL; 1850 1851 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1852 if (err) 1853 goto err_finish; 1854 1855 err = -EINVAL; 1856 if (oh.len != nbytes) 1857 goto err_finish; 1858 1859 /* 1860 * Zero oh.unique indicates unsolicited notification message 1861 * and error contains notification code. 1862 */ 1863 if (!oh.unique) { 1864 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1865 return err ? err : nbytes; 1866 } 1867 1868 err = -EINVAL; 1869 if (oh.error <= -1000 || oh.error > 0) 1870 goto err_finish; 1871 1872 spin_lock(&fpq->lock); 1873 err = -ENOENT; 1874 if (!fpq->connected) 1875 goto err_unlock_pq; 1876 1877 req = request_find(fpq, oh.unique); 1878 if (!req) 1879 goto err_unlock_pq; 1880 1881 /* Is it an interrupt reply? */ 1882 if (req->intr_unique == oh.unique) { 1883 spin_unlock(&fpq->lock); 1884 1885 err = -EINVAL; 1886 if (nbytes != sizeof(struct fuse_out_header)) 1887 goto err_finish; 1888 1889 if (oh.error == -ENOSYS) 1890 fc->no_interrupt = 1; 1891 else if (oh.error == -EAGAIN) 1892 queue_interrupt(&fc->iq, req); 1893 1894 fuse_copy_finish(cs); 1895 return nbytes; 1896 } 1897 1898 clear_bit(FR_SENT, &req->flags); 1899 list_move(&req->list, &fpq->io); 1900 req->out.h = oh; 1901 set_bit(FR_LOCKED, &req->flags); 1902 spin_unlock(&fpq->lock); 1903 cs->req = req; 1904 if (!req->out.page_replace) 1905 cs->move_pages = 0; 1906 1907 err = copy_out_args(cs, &req->out, nbytes); 1908 fuse_copy_finish(cs); 1909 1910 spin_lock(&fpq->lock); 1911 clear_bit(FR_LOCKED, &req->flags); 1912 if (!fpq->connected) 1913 err = -ENOENT; 1914 else if (err) 1915 req->out.h.error = -EIO; 1916 if (!test_bit(FR_PRIVATE, &req->flags)) 1917 list_del_init(&req->list); 1918 spin_unlock(&fpq->lock); 1919 1920 request_end(fc, req); 1921 1922 return err ? err : nbytes; 1923 1924 err_unlock_pq: 1925 spin_unlock(&fpq->lock); 1926 err_finish: 1927 fuse_copy_finish(cs); 1928 return err; 1929 } 1930 1931 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1932 { 1933 struct fuse_copy_state cs; 1934 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1935 1936 if (!fud) 1937 return -EPERM; 1938 1939 if (!iter_is_iovec(from)) 1940 return -EINVAL; 1941 1942 fuse_copy_init(&cs, 0, from); 1943 1944 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1945 } 1946 1947 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1948 struct file *out, loff_t *ppos, 1949 size_t len, unsigned int flags) 1950 { 1951 unsigned nbuf; 1952 unsigned idx; 1953 struct pipe_buffer *bufs; 1954 struct fuse_copy_state cs; 1955 struct fuse_dev *fud; 1956 size_t rem; 1957 ssize_t ret; 1958 1959 fud = fuse_get_dev(out); 1960 if (!fud) 1961 return -EPERM; 1962 1963 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1964 if (!bufs) 1965 return -ENOMEM; 1966 1967 pipe_lock(pipe); 1968 nbuf = 0; 1969 rem = 0; 1970 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) 1971 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; 1972 1973 ret = -EINVAL; 1974 if (rem < len) { 1975 pipe_unlock(pipe); 1976 goto out; 1977 } 1978 1979 rem = len; 1980 while (rem) { 1981 struct pipe_buffer *ibuf; 1982 struct pipe_buffer *obuf; 1983 1984 BUG_ON(nbuf >= pipe->buffers); 1985 BUG_ON(!pipe->nrbufs); 1986 ibuf = &pipe->bufs[pipe->curbuf]; 1987 obuf = &bufs[nbuf]; 1988 1989 if (rem >= ibuf->len) { 1990 *obuf = *ibuf; 1991 ibuf->ops = NULL; 1992 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 1993 pipe->nrbufs--; 1994 } else { 1995 ibuf->ops->get(pipe, ibuf); 1996 *obuf = *ibuf; 1997 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1998 obuf->len = rem; 1999 ibuf->offset += obuf->len; 2000 ibuf->len -= obuf->len; 2001 } 2002 nbuf++; 2003 rem -= obuf->len; 2004 } 2005 pipe_unlock(pipe); 2006 2007 fuse_copy_init(&cs, 0, NULL); 2008 cs.pipebufs = bufs; 2009 cs.nr_segs = nbuf; 2010 cs.pipe = pipe; 2011 2012 if (flags & SPLICE_F_MOVE) 2013 cs.move_pages = 1; 2014 2015 ret = fuse_dev_do_write(fud, &cs, len); 2016 2017 for (idx = 0; idx < nbuf; idx++) { 2018 struct pipe_buffer *buf = &bufs[idx]; 2019 buf->ops->release(pipe, buf); 2020 } 2021 out: 2022 kfree(bufs); 2023 return ret; 2024 } 2025 2026 static unsigned fuse_dev_poll(struct file *file, poll_table *wait) 2027 { 2028 unsigned mask = POLLOUT | POLLWRNORM; 2029 struct fuse_iqueue *fiq; 2030 struct fuse_dev *fud = fuse_get_dev(file); 2031 2032 if (!fud) 2033 return POLLERR; 2034 2035 fiq = &fud->fc->iq; 2036 poll_wait(file, &fiq->waitq, wait); 2037 2038 spin_lock(&fiq->waitq.lock); 2039 if (!fiq->connected) 2040 mask = POLLERR; 2041 else if (request_pending(fiq)) 2042 mask |= POLLIN | POLLRDNORM; 2043 spin_unlock(&fiq->waitq.lock); 2044 2045 return mask; 2046 } 2047 2048 /* 2049 * Abort all requests on the given list (pending or processing) 2050 * 2051 * This function releases and reacquires fc->lock 2052 */ 2053 static void end_requests(struct fuse_conn *fc, struct list_head *head) 2054 { 2055 while (!list_empty(head)) { 2056 struct fuse_req *req; 2057 req = list_entry(head->next, struct fuse_req, list); 2058 req->out.h.error = -ECONNABORTED; 2059 clear_bit(FR_PENDING, &req->flags); 2060 clear_bit(FR_SENT, &req->flags); 2061 list_del_init(&req->list); 2062 request_end(fc, req); 2063 } 2064 } 2065 2066 static void end_polls(struct fuse_conn *fc) 2067 { 2068 struct rb_node *p; 2069 2070 p = rb_first(&fc->polled_files); 2071 2072 while (p) { 2073 struct fuse_file *ff; 2074 ff = rb_entry(p, struct fuse_file, polled_node); 2075 wake_up_interruptible_all(&ff->poll_wait); 2076 2077 p = rb_next(p); 2078 } 2079 } 2080 2081 /* 2082 * Abort all requests. 2083 * 2084 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2085 * filesystem. 2086 * 2087 * The same effect is usually achievable through killing the filesystem daemon 2088 * and all users of the filesystem. The exception is the combination of an 2089 * asynchronous request and the tricky deadlock (see 2090 * Documentation/filesystems/fuse.txt). 2091 * 2092 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2093 * requests, they should be finished off immediately. Locked requests will be 2094 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2095 * requests. It is possible that some request will finish before we can. This 2096 * is OK, the request will in that case be removed from the list before we touch 2097 * it. 2098 */ 2099 void fuse_abort_conn(struct fuse_conn *fc) 2100 { 2101 struct fuse_iqueue *fiq = &fc->iq; 2102 2103 spin_lock(&fc->lock); 2104 if (fc->connected) { 2105 struct fuse_dev *fud; 2106 struct fuse_req *req, *next; 2107 LIST_HEAD(to_end1); 2108 LIST_HEAD(to_end2); 2109 2110 fc->connected = 0; 2111 fc->blocked = 0; 2112 fuse_set_initialized(fc); 2113 list_for_each_entry(fud, &fc->devices, entry) { 2114 struct fuse_pqueue *fpq = &fud->pq; 2115 2116 spin_lock(&fpq->lock); 2117 fpq->connected = 0; 2118 list_for_each_entry_safe(req, next, &fpq->io, list) { 2119 req->out.h.error = -ECONNABORTED; 2120 spin_lock(&req->waitq.lock); 2121 set_bit(FR_ABORTED, &req->flags); 2122 if (!test_bit(FR_LOCKED, &req->flags)) { 2123 set_bit(FR_PRIVATE, &req->flags); 2124 list_move(&req->list, &to_end1); 2125 } 2126 spin_unlock(&req->waitq.lock); 2127 } 2128 list_splice_init(&fpq->processing, &to_end2); 2129 spin_unlock(&fpq->lock); 2130 } 2131 fc->max_background = UINT_MAX; 2132 flush_bg_queue(fc); 2133 2134 spin_lock(&fiq->waitq.lock); 2135 fiq->connected = 0; 2136 list_splice_init(&fiq->pending, &to_end2); 2137 while (forget_pending(fiq)) 2138 kfree(dequeue_forget(fiq, 1, NULL)); 2139 wake_up_all_locked(&fiq->waitq); 2140 spin_unlock(&fiq->waitq.lock); 2141 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2142 end_polls(fc); 2143 wake_up_all(&fc->blocked_waitq); 2144 spin_unlock(&fc->lock); 2145 2146 while (!list_empty(&to_end1)) { 2147 req = list_first_entry(&to_end1, struct fuse_req, list); 2148 __fuse_get_request(req); 2149 list_del_init(&req->list); 2150 request_end(fc, req); 2151 } 2152 end_requests(fc, &to_end2); 2153 } else { 2154 spin_unlock(&fc->lock); 2155 } 2156 } 2157 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2158 2159 int fuse_dev_release(struct inode *inode, struct file *file) 2160 { 2161 struct fuse_dev *fud = fuse_get_dev(file); 2162 2163 if (fud) { 2164 struct fuse_conn *fc = fud->fc; 2165 struct fuse_pqueue *fpq = &fud->pq; 2166 2167 WARN_ON(!list_empty(&fpq->io)); 2168 end_requests(fc, &fpq->processing); 2169 /* Are we the last open device? */ 2170 if (atomic_dec_and_test(&fc->dev_count)) { 2171 WARN_ON(fc->iq.fasync != NULL); 2172 fuse_abort_conn(fc); 2173 } 2174 fuse_dev_free(fud); 2175 } 2176 return 0; 2177 } 2178 EXPORT_SYMBOL_GPL(fuse_dev_release); 2179 2180 static int fuse_dev_fasync(int fd, struct file *file, int on) 2181 { 2182 struct fuse_dev *fud = fuse_get_dev(file); 2183 2184 if (!fud) 2185 return -EPERM; 2186 2187 /* No locking - fasync_helper does its own locking */ 2188 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2189 } 2190 2191 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2192 { 2193 struct fuse_dev *fud; 2194 2195 if (new->private_data) 2196 return -EINVAL; 2197 2198 fud = fuse_dev_alloc(fc); 2199 if (!fud) 2200 return -ENOMEM; 2201 2202 new->private_data = fud; 2203 atomic_inc(&fc->dev_count); 2204 2205 return 0; 2206 } 2207 2208 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2209 unsigned long arg) 2210 { 2211 int err = -ENOTTY; 2212 2213 if (cmd == FUSE_DEV_IOC_CLONE) { 2214 int oldfd; 2215 2216 err = -EFAULT; 2217 if (!get_user(oldfd, (__u32 __user *) arg)) { 2218 struct file *old = fget(oldfd); 2219 2220 err = -EINVAL; 2221 if (old) { 2222 struct fuse_dev *fud = NULL; 2223 2224 /* 2225 * Check against file->f_op because CUSE 2226 * uses the same ioctl handler. 2227 */ 2228 if (old->f_op == file->f_op && 2229 old->f_cred->user_ns == file->f_cred->user_ns) 2230 fud = fuse_get_dev(old); 2231 2232 if (fud) { 2233 mutex_lock(&fuse_mutex); 2234 err = fuse_device_clone(fud->fc, file); 2235 mutex_unlock(&fuse_mutex); 2236 } 2237 fput(old); 2238 } 2239 } 2240 } 2241 return err; 2242 } 2243 2244 const struct file_operations fuse_dev_operations = { 2245 .owner = THIS_MODULE, 2246 .open = fuse_dev_open, 2247 .llseek = no_llseek, 2248 .read_iter = fuse_dev_read, 2249 .splice_read = fuse_dev_splice_read, 2250 .write_iter = fuse_dev_write, 2251 .splice_write = fuse_dev_splice_write, 2252 .poll = fuse_dev_poll, 2253 .release = fuse_dev_release, 2254 .fasync = fuse_dev_fasync, 2255 .unlocked_ioctl = fuse_dev_ioctl, 2256 .compat_ioctl = fuse_dev_ioctl, 2257 }; 2258 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2259 2260 static struct miscdevice fuse_miscdevice = { 2261 .minor = FUSE_MINOR, 2262 .name = "fuse", 2263 .fops = &fuse_dev_operations, 2264 }; 2265 2266 int __init fuse_dev_init(void) 2267 { 2268 int err = -ENOMEM; 2269 fuse_req_cachep = kmem_cache_create("fuse_request", 2270 sizeof(struct fuse_req), 2271 0, 0, NULL); 2272 if (!fuse_req_cachep) 2273 goto out; 2274 2275 err = misc_register(&fuse_miscdevice); 2276 if (err) 2277 goto out_cache_clean; 2278 2279 return 0; 2280 2281 out_cache_clean: 2282 kmem_cache_destroy(fuse_req_cachep); 2283 out: 2284 return err; 2285 } 2286 2287 void fuse_dev_cleanup(void) 2288 { 2289 misc_deregister(&fuse_miscdevice); 2290 kmem_cache_destroy(fuse_req_cachep); 2291 } 2292