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 cs->offset = off; 771 iov_iter_advance(cs->iter, err); 772 } 773 774 return lock_request(cs->req); 775 } 776 777 /* Do as much copy to/from userspace buffer as we can */ 778 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 779 { 780 unsigned ncpy = min(*size, cs->len); 781 if (val) { 782 void *pgaddr = kmap_atomic(cs->pg); 783 void *buf = pgaddr + cs->offset; 784 785 if (cs->write) 786 memcpy(buf, *val, ncpy); 787 else 788 memcpy(*val, buf, ncpy); 789 790 kunmap_atomic(pgaddr); 791 *val += ncpy; 792 } 793 *size -= ncpy; 794 cs->len -= ncpy; 795 cs->offset += ncpy; 796 return ncpy; 797 } 798 799 static int fuse_check_page(struct page *page) 800 { 801 if (page_mapcount(page) || 802 page->mapping != NULL || 803 page_count(page) != 1 || 804 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 805 ~(1 << PG_locked | 806 1 << PG_referenced | 807 1 << PG_uptodate | 808 1 << PG_lru | 809 1 << PG_active | 810 1 << PG_reclaim))) { 811 printk(KERN_WARNING "fuse: trying to steal weird page\n"); 812 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); 813 return 1; 814 } 815 return 0; 816 } 817 818 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 819 { 820 int err; 821 struct page *oldpage = *pagep; 822 struct page *newpage; 823 struct pipe_buffer *buf = cs->pipebufs; 824 825 err = unlock_request(cs->req); 826 if (err) 827 return err; 828 829 fuse_copy_finish(cs); 830 831 err = buf->ops->confirm(cs->pipe, buf); 832 if (err) 833 return err; 834 835 BUG_ON(!cs->nr_segs); 836 cs->currbuf = buf; 837 cs->len = buf->len; 838 cs->pipebufs++; 839 cs->nr_segs--; 840 841 if (cs->len != PAGE_SIZE) 842 goto out_fallback; 843 844 if (buf->ops->steal(cs->pipe, buf) != 0) 845 goto out_fallback; 846 847 newpage = buf->page; 848 849 if (!PageUptodate(newpage)) 850 SetPageUptodate(newpage); 851 852 ClearPageMappedToDisk(newpage); 853 854 if (fuse_check_page(newpage) != 0) 855 goto out_fallback_unlock; 856 857 /* 858 * This is a new and locked page, it shouldn't be mapped or 859 * have any special flags on it 860 */ 861 if (WARN_ON(page_mapped(oldpage))) 862 goto out_fallback_unlock; 863 if (WARN_ON(page_has_private(oldpage))) 864 goto out_fallback_unlock; 865 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 866 goto out_fallback_unlock; 867 if (WARN_ON(PageMlocked(oldpage))) 868 goto out_fallback_unlock; 869 870 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); 871 if (err) { 872 unlock_page(newpage); 873 return err; 874 } 875 876 get_page(newpage); 877 878 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 879 lru_cache_add_file(newpage); 880 881 err = 0; 882 spin_lock(&cs->req->waitq.lock); 883 if (test_bit(FR_ABORTED, &cs->req->flags)) 884 err = -ENOENT; 885 else 886 *pagep = newpage; 887 spin_unlock(&cs->req->waitq.lock); 888 889 if (err) { 890 unlock_page(newpage); 891 put_page(newpage); 892 return err; 893 } 894 895 unlock_page(oldpage); 896 put_page(oldpage); 897 cs->len = 0; 898 899 return 0; 900 901 out_fallback_unlock: 902 unlock_page(newpage); 903 out_fallback: 904 cs->pg = buf->page; 905 cs->offset = buf->offset; 906 907 err = lock_request(cs->req); 908 if (err) 909 return err; 910 911 return 1; 912 } 913 914 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 915 unsigned offset, unsigned count) 916 { 917 struct pipe_buffer *buf; 918 int err; 919 920 if (cs->nr_segs == cs->pipe->buffers) 921 return -EIO; 922 923 err = unlock_request(cs->req); 924 if (err) 925 return err; 926 927 fuse_copy_finish(cs); 928 929 buf = cs->pipebufs; 930 get_page(page); 931 buf->page = page; 932 buf->offset = offset; 933 buf->len = count; 934 935 cs->pipebufs++; 936 cs->nr_segs++; 937 cs->len = 0; 938 939 return 0; 940 } 941 942 /* 943 * Copy a page in the request to/from the userspace buffer. Must be 944 * done atomically 945 */ 946 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 947 unsigned offset, unsigned count, int zeroing) 948 { 949 int err; 950 struct page *page = *pagep; 951 952 if (page && zeroing && count < PAGE_SIZE) 953 clear_highpage(page); 954 955 while (count) { 956 if (cs->write && cs->pipebufs && page) { 957 return fuse_ref_page(cs, page, offset, count); 958 } else if (!cs->len) { 959 if (cs->move_pages && page && 960 offset == 0 && count == PAGE_SIZE) { 961 err = fuse_try_move_page(cs, pagep); 962 if (err <= 0) 963 return err; 964 } else { 965 err = fuse_copy_fill(cs); 966 if (err) 967 return err; 968 } 969 } 970 if (page) { 971 void *mapaddr = kmap_atomic(page); 972 void *buf = mapaddr + offset; 973 offset += fuse_copy_do(cs, &buf, &count); 974 kunmap_atomic(mapaddr); 975 } else 976 offset += fuse_copy_do(cs, NULL, &count); 977 } 978 if (page && !cs->write) 979 flush_dcache_page(page); 980 return 0; 981 } 982 983 /* Copy pages in the request to/from userspace buffer */ 984 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 985 int zeroing) 986 { 987 unsigned i; 988 struct fuse_req *req = cs->req; 989 990 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { 991 int err; 992 unsigned offset = req->page_descs[i].offset; 993 unsigned count = min(nbytes, req->page_descs[i].length); 994 995 err = fuse_copy_page(cs, &req->pages[i], offset, count, 996 zeroing); 997 if (err) 998 return err; 999 1000 nbytes -= count; 1001 } 1002 return 0; 1003 } 1004 1005 /* Copy a single argument in the request to/from userspace buffer */ 1006 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 1007 { 1008 while (size) { 1009 if (!cs->len) { 1010 int err = fuse_copy_fill(cs); 1011 if (err) 1012 return err; 1013 } 1014 fuse_copy_do(cs, &val, &size); 1015 } 1016 return 0; 1017 } 1018 1019 /* Copy request arguments to/from userspace buffer */ 1020 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1021 unsigned argpages, struct fuse_arg *args, 1022 int zeroing) 1023 { 1024 int err = 0; 1025 unsigned i; 1026 1027 for (i = 0; !err && i < numargs; i++) { 1028 struct fuse_arg *arg = &args[i]; 1029 if (i == numargs - 1 && argpages) 1030 err = fuse_copy_pages(cs, arg->size, zeroing); 1031 else 1032 err = fuse_copy_one(cs, arg->value, arg->size); 1033 } 1034 return err; 1035 } 1036 1037 static int forget_pending(struct fuse_iqueue *fiq) 1038 { 1039 return fiq->forget_list_head.next != NULL; 1040 } 1041 1042 static int request_pending(struct fuse_iqueue *fiq) 1043 { 1044 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1045 forget_pending(fiq); 1046 } 1047 1048 /* 1049 * Transfer an interrupt request to userspace 1050 * 1051 * Unlike other requests this is assembled on demand, without a need 1052 * to allocate a separate fuse_req structure. 1053 * 1054 * Called with fiq->waitq.lock held, releases it 1055 */ 1056 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1057 struct fuse_copy_state *cs, 1058 size_t nbytes, struct fuse_req *req) 1059 __releases(fiq->waitq.lock) 1060 { 1061 struct fuse_in_header ih; 1062 struct fuse_interrupt_in arg; 1063 unsigned reqsize = sizeof(ih) + sizeof(arg); 1064 int err; 1065 1066 list_del_init(&req->intr_entry); 1067 req->intr_unique = fuse_get_unique(fiq); 1068 memset(&ih, 0, sizeof(ih)); 1069 memset(&arg, 0, sizeof(arg)); 1070 ih.len = reqsize; 1071 ih.opcode = FUSE_INTERRUPT; 1072 ih.unique = req->intr_unique; 1073 arg.unique = req->in.h.unique; 1074 1075 spin_unlock(&fiq->waitq.lock); 1076 if (nbytes < reqsize) 1077 return -EINVAL; 1078 1079 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1080 if (!err) 1081 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1082 fuse_copy_finish(cs); 1083 1084 return err ? err : reqsize; 1085 } 1086 1087 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq, 1088 unsigned max, 1089 unsigned *countp) 1090 { 1091 struct fuse_forget_link *head = fiq->forget_list_head.next; 1092 struct fuse_forget_link **newhead = &head; 1093 unsigned count; 1094 1095 for (count = 0; *newhead != NULL && count < max; count++) 1096 newhead = &(*newhead)->next; 1097 1098 fiq->forget_list_head.next = *newhead; 1099 *newhead = NULL; 1100 if (fiq->forget_list_head.next == NULL) 1101 fiq->forget_list_tail = &fiq->forget_list_head; 1102 1103 if (countp != NULL) 1104 *countp = count; 1105 1106 return head; 1107 } 1108 1109 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1110 struct fuse_copy_state *cs, 1111 size_t nbytes) 1112 __releases(fiq->waitq.lock) 1113 { 1114 int err; 1115 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL); 1116 struct fuse_forget_in arg = { 1117 .nlookup = forget->forget_one.nlookup, 1118 }; 1119 struct fuse_in_header ih = { 1120 .opcode = FUSE_FORGET, 1121 .nodeid = forget->forget_one.nodeid, 1122 .unique = fuse_get_unique(fiq), 1123 .len = sizeof(ih) + sizeof(arg), 1124 }; 1125 1126 spin_unlock(&fiq->waitq.lock); 1127 kfree(forget); 1128 if (nbytes < ih.len) 1129 return -EINVAL; 1130 1131 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1132 if (!err) 1133 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1134 fuse_copy_finish(cs); 1135 1136 if (err) 1137 return err; 1138 1139 return ih.len; 1140 } 1141 1142 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1143 struct fuse_copy_state *cs, size_t nbytes) 1144 __releases(fiq->waitq.lock) 1145 { 1146 int err; 1147 unsigned max_forgets; 1148 unsigned count; 1149 struct fuse_forget_link *head; 1150 struct fuse_batch_forget_in arg = { .count = 0 }; 1151 struct fuse_in_header ih = { 1152 .opcode = FUSE_BATCH_FORGET, 1153 .unique = fuse_get_unique(fiq), 1154 .len = sizeof(ih) + sizeof(arg), 1155 }; 1156 1157 if (nbytes < ih.len) { 1158 spin_unlock(&fiq->waitq.lock); 1159 return -EINVAL; 1160 } 1161 1162 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1163 head = dequeue_forget(fiq, max_forgets, &count); 1164 spin_unlock(&fiq->waitq.lock); 1165 1166 arg.count = count; 1167 ih.len += count * sizeof(struct fuse_forget_one); 1168 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1169 if (!err) 1170 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1171 1172 while (head) { 1173 struct fuse_forget_link *forget = head; 1174 1175 if (!err) { 1176 err = fuse_copy_one(cs, &forget->forget_one, 1177 sizeof(forget->forget_one)); 1178 } 1179 head = forget->next; 1180 kfree(forget); 1181 } 1182 1183 fuse_copy_finish(cs); 1184 1185 if (err) 1186 return err; 1187 1188 return ih.len; 1189 } 1190 1191 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1192 struct fuse_copy_state *cs, 1193 size_t nbytes) 1194 __releases(fiq->waitq.lock) 1195 { 1196 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1197 return fuse_read_single_forget(fiq, cs, nbytes); 1198 else 1199 return fuse_read_batch_forget(fiq, cs, nbytes); 1200 } 1201 1202 /* 1203 * Read a single request into the userspace filesystem's buffer. This 1204 * function waits until a request is available, then removes it from 1205 * the pending list and copies request data to userspace buffer. If 1206 * no reply is needed (FORGET) or request has been aborted or there 1207 * was an error during the copying then it's finished by calling 1208 * request_end(). Otherwise add it to the processing list, and set 1209 * the 'sent' flag. 1210 */ 1211 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1212 struct fuse_copy_state *cs, size_t nbytes) 1213 { 1214 ssize_t err; 1215 struct fuse_conn *fc = fud->fc; 1216 struct fuse_iqueue *fiq = &fc->iq; 1217 struct fuse_pqueue *fpq = &fud->pq; 1218 struct fuse_req *req; 1219 struct fuse_in *in; 1220 unsigned reqsize; 1221 1222 restart: 1223 spin_lock(&fiq->waitq.lock); 1224 err = -EAGAIN; 1225 if ((file->f_flags & O_NONBLOCK) && fiq->connected && 1226 !request_pending(fiq)) 1227 goto err_unlock; 1228 1229 err = wait_event_interruptible_exclusive_locked(fiq->waitq, 1230 !fiq->connected || request_pending(fiq)); 1231 if (err) 1232 goto err_unlock; 1233 1234 err = -ENODEV; 1235 if (!fiq->connected) 1236 goto err_unlock; 1237 1238 if (!list_empty(&fiq->interrupts)) { 1239 req = list_entry(fiq->interrupts.next, struct fuse_req, 1240 intr_entry); 1241 return fuse_read_interrupt(fiq, cs, nbytes, req); 1242 } 1243 1244 if (forget_pending(fiq)) { 1245 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1246 return fuse_read_forget(fc, fiq, cs, nbytes); 1247 1248 if (fiq->forget_batch <= -8) 1249 fiq->forget_batch = 16; 1250 } 1251 1252 req = list_entry(fiq->pending.next, struct fuse_req, list); 1253 clear_bit(FR_PENDING, &req->flags); 1254 list_del_init(&req->list); 1255 spin_unlock(&fiq->waitq.lock); 1256 1257 in = &req->in; 1258 reqsize = in->h.len; 1259 /* If request is too large, reply with an error and restart the read */ 1260 if (nbytes < reqsize) { 1261 req->out.h.error = -EIO; 1262 /* SETXATTR is special, since it may contain too large data */ 1263 if (in->h.opcode == FUSE_SETXATTR) 1264 req->out.h.error = -E2BIG; 1265 request_end(fc, req); 1266 goto restart; 1267 } 1268 spin_lock(&fpq->lock); 1269 list_add(&req->list, &fpq->io); 1270 spin_unlock(&fpq->lock); 1271 cs->req = req; 1272 err = fuse_copy_one(cs, &in->h, sizeof(in->h)); 1273 if (!err) 1274 err = fuse_copy_args(cs, in->numargs, in->argpages, 1275 (struct fuse_arg *) in->args, 0); 1276 fuse_copy_finish(cs); 1277 spin_lock(&fpq->lock); 1278 clear_bit(FR_LOCKED, &req->flags); 1279 if (!fpq->connected) { 1280 err = -ENODEV; 1281 goto out_end; 1282 } 1283 if (err) { 1284 req->out.h.error = -EIO; 1285 goto out_end; 1286 } 1287 if (!test_bit(FR_ISREPLY, &req->flags)) { 1288 err = reqsize; 1289 goto out_end; 1290 } 1291 list_move_tail(&req->list, &fpq->processing); 1292 spin_unlock(&fpq->lock); 1293 set_bit(FR_SENT, &req->flags); 1294 /* matches barrier in request_wait_answer() */ 1295 smp_mb__after_atomic(); 1296 if (test_bit(FR_INTERRUPTED, &req->flags)) 1297 queue_interrupt(fiq, req); 1298 1299 return reqsize; 1300 1301 out_end: 1302 if (!test_bit(FR_PRIVATE, &req->flags)) 1303 list_del_init(&req->list); 1304 spin_unlock(&fpq->lock); 1305 request_end(fc, req); 1306 return err; 1307 1308 err_unlock: 1309 spin_unlock(&fiq->waitq.lock); 1310 return err; 1311 } 1312 1313 static int fuse_dev_open(struct inode *inode, struct file *file) 1314 { 1315 /* 1316 * The fuse device's file's private_data is used to hold 1317 * the fuse_conn(ection) when it is mounted, and is used to 1318 * keep track of whether the file has been mounted already. 1319 */ 1320 file->private_data = NULL; 1321 return 0; 1322 } 1323 1324 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1325 { 1326 struct fuse_copy_state cs; 1327 struct file *file = iocb->ki_filp; 1328 struct fuse_dev *fud = fuse_get_dev(file); 1329 1330 if (!fud) 1331 return -EPERM; 1332 1333 if (!iter_is_iovec(to)) 1334 return -EINVAL; 1335 1336 fuse_copy_init(&cs, 1, to); 1337 1338 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1339 } 1340 1341 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1342 struct pipe_inode_info *pipe, 1343 size_t len, unsigned int flags) 1344 { 1345 int ret; 1346 int page_nr = 0; 1347 int do_wakeup = 0; 1348 struct pipe_buffer *bufs; 1349 struct fuse_copy_state cs; 1350 struct fuse_dev *fud = fuse_get_dev(in); 1351 1352 if (!fud) 1353 return -EPERM; 1354 1355 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1356 if (!bufs) 1357 return -ENOMEM; 1358 1359 fuse_copy_init(&cs, 1, NULL); 1360 cs.pipebufs = bufs; 1361 cs.pipe = pipe; 1362 ret = fuse_dev_do_read(fud, in, &cs, len); 1363 if (ret < 0) 1364 goto out; 1365 1366 ret = 0; 1367 pipe_lock(pipe); 1368 1369 if (!pipe->readers) { 1370 send_sig(SIGPIPE, current, 0); 1371 if (!ret) 1372 ret = -EPIPE; 1373 goto out_unlock; 1374 } 1375 1376 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) { 1377 ret = -EIO; 1378 goto out_unlock; 1379 } 1380 1381 while (page_nr < cs.nr_segs) { 1382 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 1383 struct pipe_buffer *buf = pipe->bufs + newbuf; 1384 1385 buf->page = bufs[page_nr].page; 1386 buf->offset = bufs[page_nr].offset; 1387 buf->len = bufs[page_nr].len; 1388 /* 1389 * Need to be careful about this. Having buf->ops in module 1390 * code can Oops if the buffer persists after module unload. 1391 */ 1392 buf->ops = &nosteal_pipe_buf_ops; 1393 1394 pipe->nrbufs++; 1395 page_nr++; 1396 ret += buf->len; 1397 1398 if (pipe->files) 1399 do_wakeup = 1; 1400 } 1401 1402 out_unlock: 1403 pipe_unlock(pipe); 1404 1405 if (do_wakeup) { 1406 smp_mb(); 1407 if (waitqueue_active(&pipe->wait)) 1408 wake_up_interruptible(&pipe->wait); 1409 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 1410 } 1411 1412 out: 1413 for (; page_nr < cs.nr_segs; page_nr++) 1414 put_page(bufs[page_nr].page); 1415 1416 kfree(bufs); 1417 return ret; 1418 } 1419 1420 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1421 struct fuse_copy_state *cs) 1422 { 1423 struct fuse_notify_poll_wakeup_out outarg; 1424 int err = -EINVAL; 1425 1426 if (size != sizeof(outarg)) 1427 goto err; 1428 1429 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1430 if (err) 1431 goto err; 1432 1433 fuse_copy_finish(cs); 1434 return fuse_notify_poll_wakeup(fc, &outarg); 1435 1436 err: 1437 fuse_copy_finish(cs); 1438 return err; 1439 } 1440 1441 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1442 struct fuse_copy_state *cs) 1443 { 1444 struct fuse_notify_inval_inode_out outarg; 1445 int err = -EINVAL; 1446 1447 if (size != sizeof(outarg)) 1448 goto err; 1449 1450 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1451 if (err) 1452 goto err; 1453 fuse_copy_finish(cs); 1454 1455 down_read(&fc->killsb); 1456 err = -ENOENT; 1457 if (fc->sb) { 1458 err = fuse_reverse_inval_inode(fc->sb, outarg.ino, 1459 outarg.off, outarg.len); 1460 } 1461 up_read(&fc->killsb); 1462 return err; 1463 1464 err: 1465 fuse_copy_finish(cs); 1466 return err; 1467 } 1468 1469 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1470 struct fuse_copy_state *cs) 1471 { 1472 struct fuse_notify_inval_entry_out outarg; 1473 int err = -ENOMEM; 1474 char *buf; 1475 struct qstr name; 1476 1477 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1478 if (!buf) 1479 goto err; 1480 1481 err = -EINVAL; 1482 if (size < sizeof(outarg)) 1483 goto err; 1484 1485 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1486 if (err) 1487 goto err; 1488 1489 err = -ENAMETOOLONG; 1490 if (outarg.namelen > FUSE_NAME_MAX) 1491 goto err; 1492 1493 err = -EINVAL; 1494 if (size != sizeof(outarg) + outarg.namelen + 1) 1495 goto err; 1496 1497 name.name = buf; 1498 name.len = outarg.namelen; 1499 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1500 if (err) 1501 goto err; 1502 fuse_copy_finish(cs); 1503 buf[outarg.namelen] = 0; 1504 1505 down_read(&fc->killsb); 1506 err = -ENOENT; 1507 if (fc->sb) 1508 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name); 1509 up_read(&fc->killsb); 1510 kfree(buf); 1511 return err; 1512 1513 err: 1514 kfree(buf); 1515 fuse_copy_finish(cs); 1516 return err; 1517 } 1518 1519 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1520 struct fuse_copy_state *cs) 1521 { 1522 struct fuse_notify_delete_out outarg; 1523 int err = -ENOMEM; 1524 char *buf; 1525 struct qstr name; 1526 1527 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1528 if (!buf) 1529 goto err; 1530 1531 err = -EINVAL; 1532 if (size < sizeof(outarg)) 1533 goto err; 1534 1535 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1536 if (err) 1537 goto err; 1538 1539 err = -ENAMETOOLONG; 1540 if (outarg.namelen > FUSE_NAME_MAX) 1541 goto err; 1542 1543 err = -EINVAL; 1544 if (size != sizeof(outarg) + outarg.namelen + 1) 1545 goto err; 1546 1547 name.name = buf; 1548 name.len = outarg.namelen; 1549 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1550 if (err) 1551 goto err; 1552 fuse_copy_finish(cs); 1553 buf[outarg.namelen] = 0; 1554 1555 down_read(&fc->killsb); 1556 err = -ENOENT; 1557 if (fc->sb) 1558 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 1559 outarg.child, &name); 1560 up_read(&fc->killsb); 1561 kfree(buf); 1562 return err; 1563 1564 err: 1565 kfree(buf); 1566 fuse_copy_finish(cs); 1567 return err; 1568 } 1569 1570 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1571 struct fuse_copy_state *cs) 1572 { 1573 struct fuse_notify_store_out outarg; 1574 struct inode *inode; 1575 struct address_space *mapping; 1576 u64 nodeid; 1577 int err; 1578 pgoff_t index; 1579 unsigned int offset; 1580 unsigned int num; 1581 loff_t file_size; 1582 loff_t end; 1583 1584 err = -EINVAL; 1585 if (size < sizeof(outarg)) 1586 goto out_finish; 1587 1588 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1589 if (err) 1590 goto out_finish; 1591 1592 err = -EINVAL; 1593 if (size - sizeof(outarg) != outarg.size) 1594 goto out_finish; 1595 1596 nodeid = outarg.nodeid; 1597 1598 down_read(&fc->killsb); 1599 1600 err = -ENOENT; 1601 if (!fc->sb) 1602 goto out_up_killsb; 1603 1604 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1605 if (!inode) 1606 goto out_up_killsb; 1607 1608 mapping = inode->i_mapping; 1609 index = outarg.offset >> PAGE_SHIFT; 1610 offset = outarg.offset & ~PAGE_MASK; 1611 file_size = i_size_read(inode); 1612 end = outarg.offset + outarg.size; 1613 if (end > file_size) { 1614 file_size = end; 1615 fuse_write_update_size(inode, file_size); 1616 } 1617 1618 num = outarg.size; 1619 while (num) { 1620 struct page *page; 1621 unsigned int this_num; 1622 1623 err = -ENOMEM; 1624 page = find_or_create_page(mapping, index, 1625 mapping_gfp_mask(mapping)); 1626 if (!page) 1627 goto out_iput; 1628 1629 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1630 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1631 if (!err && offset == 0 && 1632 (this_num == PAGE_SIZE || file_size == end)) 1633 SetPageUptodate(page); 1634 unlock_page(page); 1635 put_page(page); 1636 1637 if (err) 1638 goto out_iput; 1639 1640 num -= this_num; 1641 offset = 0; 1642 index++; 1643 } 1644 1645 err = 0; 1646 1647 out_iput: 1648 iput(inode); 1649 out_up_killsb: 1650 up_read(&fc->killsb); 1651 out_finish: 1652 fuse_copy_finish(cs); 1653 return err; 1654 } 1655 1656 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req) 1657 { 1658 release_pages(req->pages, req->num_pages, false); 1659 } 1660 1661 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, 1662 struct fuse_notify_retrieve_out *outarg) 1663 { 1664 int err; 1665 struct address_space *mapping = inode->i_mapping; 1666 struct fuse_req *req; 1667 pgoff_t index; 1668 loff_t file_size; 1669 unsigned int num; 1670 unsigned int offset; 1671 size_t total_len = 0; 1672 int num_pages; 1673 1674 offset = outarg->offset & ~PAGE_MASK; 1675 file_size = i_size_read(inode); 1676 1677 num = outarg->size; 1678 if (outarg->offset > file_size) 1679 num = 0; 1680 else if (outarg->offset + num > file_size) 1681 num = file_size - outarg->offset; 1682 1683 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1684 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ); 1685 1686 req = fuse_get_req(fc, num_pages); 1687 if (IS_ERR(req)) 1688 return PTR_ERR(req); 1689 1690 req->in.h.opcode = FUSE_NOTIFY_REPLY; 1691 req->in.h.nodeid = outarg->nodeid; 1692 req->in.numargs = 2; 1693 req->in.argpages = 1; 1694 req->page_descs[0].offset = offset; 1695 req->end = fuse_retrieve_end; 1696 1697 index = outarg->offset >> PAGE_SHIFT; 1698 1699 while (num && req->num_pages < num_pages) { 1700 struct page *page; 1701 unsigned int this_num; 1702 1703 page = find_get_page(mapping, index); 1704 if (!page) 1705 break; 1706 1707 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1708 req->pages[req->num_pages] = page; 1709 req->page_descs[req->num_pages].length = this_num; 1710 req->num_pages++; 1711 1712 offset = 0; 1713 num -= this_num; 1714 total_len += this_num; 1715 index++; 1716 } 1717 req->misc.retrieve_in.offset = outarg->offset; 1718 req->misc.retrieve_in.size = total_len; 1719 req->in.args[0].size = sizeof(req->misc.retrieve_in); 1720 req->in.args[0].value = &req->misc.retrieve_in; 1721 req->in.args[1].size = total_len; 1722 1723 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique); 1724 if (err) 1725 fuse_retrieve_end(fc, req); 1726 1727 return err; 1728 } 1729 1730 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1731 struct fuse_copy_state *cs) 1732 { 1733 struct fuse_notify_retrieve_out outarg; 1734 struct inode *inode; 1735 int err; 1736 1737 err = -EINVAL; 1738 if (size != sizeof(outarg)) 1739 goto copy_finish; 1740 1741 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1742 if (err) 1743 goto copy_finish; 1744 1745 fuse_copy_finish(cs); 1746 1747 down_read(&fc->killsb); 1748 err = -ENOENT; 1749 if (fc->sb) { 1750 u64 nodeid = outarg.nodeid; 1751 1752 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1753 if (inode) { 1754 err = fuse_retrieve(fc, inode, &outarg); 1755 iput(inode); 1756 } 1757 } 1758 up_read(&fc->killsb); 1759 1760 return err; 1761 1762 copy_finish: 1763 fuse_copy_finish(cs); 1764 return err; 1765 } 1766 1767 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1768 unsigned int size, struct fuse_copy_state *cs) 1769 { 1770 /* Don't try to move pages (yet) */ 1771 cs->move_pages = 0; 1772 1773 switch (code) { 1774 case FUSE_NOTIFY_POLL: 1775 return fuse_notify_poll(fc, size, cs); 1776 1777 case FUSE_NOTIFY_INVAL_INODE: 1778 return fuse_notify_inval_inode(fc, size, cs); 1779 1780 case FUSE_NOTIFY_INVAL_ENTRY: 1781 return fuse_notify_inval_entry(fc, size, cs); 1782 1783 case FUSE_NOTIFY_STORE: 1784 return fuse_notify_store(fc, size, cs); 1785 1786 case FUSE_NOTIFY_RETRIEVE: 1787 return fuse_notify_retrieve(fc, size, cs); 1788 1789 case FUSE_NOTIFY_DELETE: 1790 return fuse_notify_delete(fc, size, cs); 1791 1792 default: 1793 fuse_copy_finish(cs); 1794 return -EINVAL; 1795 } 1796 } 1797 1798 /* Look up request on processing list by unique ID */ 1799 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1800 { 1801 struct fuse_req *req; 1802 1803 list_for_each_entry(req, &fpq->processing, list) { 1804 if (req->in.h.unique == unique || req->intr_unique == unique) 1805 return req; 1806 } 1807 return NULL; 1808 } 1809 1810 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, 1811 unsigned nbytes) 1812 { 1813 unsigned reqsize = sizeof(struct fuse_out_header); 1814 1815 if (out->h.error) 1816 return nbytes != reqsize ? -EINVAL : 0; 1817 1818 reqsize += len_args(out->numargs, out->args); 1819 1820 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) 1821 return -EINVAL; 1822 else if (reqsize > nbytes) { 1823 struct fuse_arg *lastarg = &out->args[out->numargs-1]; 1824 unsigned diffsize = reqsize - nbytes; 1825 if (diffsize > lastarg->size) 1826 return -EINVAL; 1827 lastarg->size -= diffsize; 1828 } 1829 return fuse_copy_args(cs, out->numargs, out->argpages, out->args, 1830 out->page_zeroing); 1831 } 1832 1833 /* 1834 * Write a single reply to a request. First the header is copied from 1835 * the write buffer. The request is then searched on the processing 1836 * list by the unique ID found in the header. If found, then remove 1837 * it from the list and copy the rest of the buffer to the request. 1838 * The request is finished by calling request_end() 1839 */ 1840 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1841 struct fuse_copy_state *cs, size_t nbytes) 1842 { 1843 int err; 1844 struct fuse_conn *fc = fud->fc; 1845 struct fuse_pqueue *fpq = &fud->pq; 1846 struct fuse_req *req; 1847 struct fuse_out_header oh; 1848 1849 if (nbytes < sizeof(struct fuse_out_header)) 1850 return -EINVAL; 1851 1852 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1853 if (err) 1854 goto err_finish; 1855 1856 err = -EINVAL; 1857 if (oh.len != nbytes) 1858 goto err_finish; 1859 1860 /* 1861 * Zero oh.unique indicates unsolicited notification message 1862 * and error contains notification code. 1863 */ 1864 if (!oh.unique) { 1865 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1866 return err ? err : nbytes; 1867 } 1868 1869 err = -EINVAL; 1870 if (oh.error <= -1000 || oh.error > 0) 1871 goto err_finish; 1872 1873 spin_lock(&fpq->lock); 1874 err = -ENOENT; 1875 if (!fpq->connected) 1876 goto err_unlock_pq; 1877 1878 req = request_find(fpq, oh.unique); 1879 if (!req) 1880 goto err_unlock_pq; 1881 1882 /* Is it an interrupt reply? */ 1883 if (req->intr_unique == oh.unique) { 1884 spin_unlock(&fpq->lock); 1885 1886 err = -EINVAL; 1887 if (nbytes != sizeof(struct fuse_out_header)) 1888 goto err_finish; 1889 1890 if (oh.error == -ENOSYS) 1891 fc->no_interrupt = 1; 1892 else if (oh.error == -EAGAIN) 1893 queue_interrupt(&fc->iq, req); 1894 1895 fuse_copy_finish(cs); 1896 return nbytes; 1897 } 1898 1899 clear_bit(FR_SENT, &req->flags); 1900 list_move(&req->list, &fpq->io); 1901 req->out.h = oh; 1902 set_bit(FR_LOCKED, &req->flags); 1903 spin_unlock(&fpq->lock); 1904 cs->req = req; 1905 if (!req->out.page_replace) 1906 cs->move_pages = 0; 1907 1908 err = copy_out_args(cs, &req->out, nbytes); 1909 fuse_copy_finish(cs); 1910 1911 spin_lock(&fpq->lock); 1912 clear_bit(FR_LOCKED, &req->flags); 1913 if (!fpq->connected) 1914 err = -ENOENT; 1915 else if (err) 1916 req->out.h.error = -EIO; 1917 if (!test_bit(FR_PRIVATE, &req->flags)) 1918 list_del_init(&req->list); 1919 spin_unlock(&fpq->lock); 1920 1921 request_end(fc, req); 1922 1923 return err ? err : nbytes; 1924 1925 err_unlock_pq: 1926 spin_unlock(&fpq->lock); 1927 err_finish: 1928 fuse_copy_finish(cs); 1929 return err; 1930 } 1931 1932 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1933 { 1934 struct fuse_copy_state cs; 1935 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1936 1937 if (!fud) 1938 return -EPERM; 1939 1940 if (!iter_is_iovec(from)) 1941 return -EINVAL; 1942 1943 fuse_copy_init(&cs, 0, from); 1944 1945 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1946 } 1947 1948 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1949 struct file *out, loff_t *ppos, 1950 size_t len, unsigned int flags) 1951 { 1952 unsigned nbuf; 1953 unsigned idx; 1954 struct pipe_buffer *bufs; 1955 struct fuse_copy_state cs; 1956 struct fuse_dev *fud; 1957 size_t rem; 1958 ssize_t ret; 1959 1960 fud = fuse_get_dev(out); 1961 if (!fud) 1962 return -EPERM; 1963 1964 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1965 if (!bufs) 1966 return -ENOMEM; 1967 1968 pipe_lock(pipe); 1969 nbuf = 0; 1970 rem = 0; 1971 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) 1972 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; 1973 1974 ret = -EINVAL; 1975 if (rem < len) { 1976 pipe_unlock(pipe); 1977 goto out; 1978 } 1979 1980 rem = len; 1981 while (rem) { 1982 struct pipe_buffer *ibuf; 1983 struct pipe_buffer *obuf; 1984 1985 BUG_ON(nbuf >= pipe->buffers); 1986 BUG_ON(!pipe->nrbufs); 1987 ibuf = &pipe->bufs[pipe->curbuf]; 1988 obuf = &bufs[nbuf]; 1989 1990 if (rem >= ibuf->len) { 1991 *obuf = *ibuf; 1992 ibuf->ops = NULL; 1993 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 1994 pipe->nrbufs--; 1995 } else { 1996 ibuf->ops->get(pipe, ibuf); 1997 *obuf = *ibuf; 1998 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1999 obuf->len = rem; 2000 ibuf->offset += obuf->len; 2001 ibuf->len -= obuf->len; 2002 } 2003 nbuf++; 2004 rem -= obuf->len; 2005 } 2006 pipe_unlock(pipe); 2007 2008 fuse_copy_init(&cs, 0, NULL); 2009 cs.pipebufs = bufs; 2010 cs.nr_segs = nbuf; 2011 cs.pipe = pipe; 2012 2013 if (flags & SPLICE_F_MOVE) 2014 cs.move_pages = 1; 2015 2016 ret = fuse_dev_do_write(fud, &cs, len); 2017 2018 for (idx = 0; idx < nbuf; idx++) { 2019 struct pipe_buffer *buf = &bufs[idx]; 2020 buf->ops->release(pipe, buf); 2021 } 2022 out: 2023 kfree(bufs); 2024 return ret; 2025 } 2026 2027 static unsigned fuse_dev_poll(struct file *file, poll_table *wait) 2028 { 2029 unsigned mask = POLLOUT | POLLWRNORM; 2030 struct fuse_iqueue *fiq; 2031 struct fuse_dev *fud = fuse_get_dev(file); 2032 2033 if (!fud) 2034 return POLLERR; 2035 2036 fiq = &fud->fc->iq; 2037 poll_wait(file, &fiq->waitq, wait); 2038 2039 spin_lock(&fiq->waitq.lock); 2040 if (!fiq->connected) 2041 mask = POLLERR; 2042 else if (request_pending(fiq)) 2043 mask |= POLLIN | POLLRDNORM; 2044 spin_unlock(&fiq->waitq.lock); 2045 2046 return mask; 2047 } 2048 2049 /* 2050 * Abort all requests on the given list (pending or processing) 2051 * 2052 * This function releases and reacquires fc->lock 2053 */ 2054 static void end_requests(struct fuse_conn *fc, struct list_head *head) 2055 { 2056 while (!list_empty(head)) { 2057 struct fuse_req *req; 2058 req = list_entry(head->next, struct fuse_req, list); 2059 req->out.h.error = -ECONNABORTED; 2060 clear_bit(FR_PENDING, &req->flags); 2061 clear_bit(FR_SENT, &req->flags); 2062 list_del_init(&req->list); 2063 request_end(fc, req); 2064 } 2065 } 2066 2067 static void end_polls(struct fuse_conn *fc) 2068 { 2069 struct rb_node *p; 2070 2071 p = rb_first(&fc->polled_files); 2072 2073 while (p) { 2074 struct fuse_file *ff; 2075 ff = rb_entry(p, struct fuse_file, polled_node); 2076 wake_up_interruptible_all(&ff->poll_wait); 2077 2078 p = rb_next(p); 2079 } 2080 } 2081 2082 /* 2083 * Abort all requests. 2084 * 2085 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2086 * filesystem. 2087 * 2088 * The same effect is usually achievable through killing the filesystem daemon 2089 * and all users of the filesystem. The exception is the combination of an 2090 * asynchronous request and the tricky deadlock (see 2091 * Documentation/filesystems/fuse.txt). 2092 * 2093 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2094 * requests, they should be finished off immediately. Locked requests will be 2095 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2096 * requests. It is possible that some request will finish before we can. This 2097 * is OK, the request will in that case be removed from the list before we touch 2098 * it. 2099 */ 2100 void fuse_abort_conn(struct fuse_conn *fc) 2101 { 2102 struct fuse_iqueue *fiq = &fc->iq; 2103 2104 spin_lock(&fc->lock); 2105 if (fc->connected) { 2106 struct fuse_dev *fud; 2107 struct fuse_req *req, *next; 2108 LIST_HEAD(to_end1); 2109 LIST_HEAD(to_end2); 2110 2111 fc->connected = 0; 2112 fc->blocked = 0; 2113 fuse_set_initialized(fc); 2114 list_for_each_entry(fud, &fc->devices, entry) { 2115 struct fuse_pqueue *fpq = &fud->pq; 2116 2117 spin_lock(&fpq->lock); 2118 fpq->connected = 0; 2119 list_for_each_entry_safe(req, next, &fpq->io, list) { 2120 req->out.h.error = -ECONNABORTED; 2121 spin_lock(&req->waitq.lock); 2122 set_bit(FR_ABORTED, &req->flags); 2123 if (!test_bit(FR_LOCKED, &req->flags)) { 2124 set_bit(FR_PRIVATE, &req->flags); 2125 list_move(&req->list, &to_end1); 2126 } 2127 spin_unlock(&req->waitq.lock); 2128 } 2129 list_splice_init(&fpq->processing, &to_end2); 2130 spin_unlock(&fpq->lock); 2131 } 2132 fc->max_background = UINT_MAX; 2133 flush_bg_queue(fc); 2134 2135 spin_lock(&fiq->waitq.lock); 2136 fiq->connected = 0; 2137 list_splice_init(&fiq->pending, &to_end2); 2138 while (forget_pending(fiq)) 2139 kfree(dequeue_forget(fiq, 1, NULL)); 2140 wake_up_all_locked(&fiq->waitq); 2141 spin_unlock(&fiq->waitq.lock); 2142 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2143 end_polls(fc); 2144 wake_up_all(&fc->blocked_waitq); 2145 spin_unlock(&fc->lock); 2146 2147 while (!list_empty(&to_end1)) { 2148 req = list_first_entry(&to_end1, struct fuse_req, list); 2149 __fuse_get_request(req); 2150 list_del_init(&req->list); 2151 request_end(fc, req); 2152 } 2153 end_requests(fc, &to_end2); 2154 } else { 2155 spin_unlock(&fc->lock); 2156 } 2157 } 2158 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2159 2160 int fuse_dev_release(struct inode *inode, struct file *file) 2161 { 2162 struct fuse_dev *fud = fuse_get_dev(file); 2163 2164 if (fud) { 2165 struct fuse_conn *fc = fud->fc; 2166 struct fuse_pqueue *fpq = &fud->pq; 2167 2168 WARN_ON(!list_empty(&fpq->io)); 2169 end_requests(fc, &fpq->processing); 2170 /* Are we the last open device? */ 2171 if (atomic_dec_and_test(&fc->dev_count)) { 2172 WARN_ON(fc->iq.fasync != NULL); 2173 fuse_abort_conn(fc); 2174 } 2175 fuse_dev_free(fud); 2176 } 2177 return 0; 2178 } 2179 EXPORT_SYMBOL_GPL(fuse_dev_release); 2180 2181 static int fuse_dev_fasync(int fd, struct file *file, int on) 2182 { 2183 struct fuse_dev *fud = fuse_get_dev(file); 2184 2185 if (!fud) 2186 return -EPERM; 2187 2188 /* No locking - fasync_helper does its own locking */ 2189 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2190 } 2191 2192 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2193 { 2194 struct fuse_dev *fud; 2195 2196 if (new->private_data) 2197 return -EINVAL; 2198 2199 fud = fuse_dev_alloc(fc); 2200 if (!fud) 2201 return -ENOMEM; 2202 2203 new->private_data = fud; 2204 atomic_inc(&fc->dev_count); 2205 2206 return 0; 2207 } 2208 2209 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2210 unsigned long arg) 2211 { 2212 int err = -ENOTTY; 2213 2214 if (cmd == FUSE_DEV_IOC_CLONE) { 2215 int oldfd; 2216 2217 err = -EFAULT; 2218 if (!get_user(oldfd, (__u32 __user *) arg)) { 2219 struct file *old = fget(oldfd); 2220 2221 err = -EINVAL; 2222 if (old) { 2223 struct fuse_dev *fud = NULL; 2224 2225 /* 2226 * Check against file->f_op because CUSE 2227 * uses the same ioctl handler. 2228 */ 2229 if (old->f_op == file->f_op && 2230 old->f_cred->user_ns == file->f_cred->user_ns) 2231 fud = fuse_get_dev(old); 2232 2233 if (fud) { 2234 mutex_lock(&fuse_mutex); 2235 err = fuse_device_clone(fud->fc, file); 2236 mutex_unlock(&fuse_mutex); 2237 } 2238 fput(old); 2239 } 2240 } 2241 } 2242 return err; 2243 } 2244 2245 const struct file_operations fuse_dev_operations = { 2246 .owner = THIS_MODULE, 2247 .open = fuse_dev_open, 2248 .llseek = no_llseek, 2249 .read_iter = fuse_dev_read, 2250 .splice_read = fuse_dev_splice_read, 2251 .write_iter = fuse_dev_write, 2252 .splice_write = fuse_dev_splice_write, 2253 .poll = fuse_dev_poll, 2254 .release = fuse_dev_release, 2255 .fasync = fuse_dev_fasync, 2256 .unlocked_ioctl = fuse_dev_ioctl, 2257 .compat_ioctl = fuse_dev_ioctl, 2258 }; 2259 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2260 2261 static struct miscdevice fuse_miscdevice = { 2262 .minor = FUSE_MINOR, 2263 .name = "fuse", 2264 .fops = &fuse_dev_operations, 2265 }; 2266 2267 int __init fuse_dev_init(void) 2268 { 2269 int err = -ENOMEM; 2270 fuse_req_cachep = kmem_cache_create("fuse_request", 2271 sizeof(struct fuse_req), 2272 0, 0, NULL); 2273 if (!fuse_req_cachep) 2274 goto out; 2275 2276 err = misc_register(&fuse_miscdevice); 2277 if (err) 2278 goto out_cache_clean; 2279 2280 return 0; 2281 2282 out_cache_clean: 2283 kmem_cache_destroy(fuse_req_cachep); 2284 out: 2285 return err; 2286 } 2287 2288 void fuse_dev_cleanup(void) 2289 { 2290 misc_deregister(&fuse_miscdevice); 2291 kmem_cache_destroy(fuse_req_cachep); 2292 } 2293