1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/poll.h> 14 #include <linux/sched/signal.h> 15 #include <linux/uio.h> 16 #include <linux/miscdevice.h> 17 #include <linux/pagemap.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/pipe_fs_i.h> 21 #include <linux/swap.h> 22 #include <linux/splice.h> 23 #include <linux/sched.h> 24 25 MODULE_ALIAS_MISCDEV(FUSE_MINOR); 26 MODULE_ALIAS("devname:fuse"); 27 28 static struct kmem_cache *fuse_req_cachep; 29 30 static struct fuse_dev *fuse_get_dev(struct file *file) 31 { 32 /* 33 * Lockless access is OK, because file->private data is set 34 * once during mount and is valid until the file is released. 35 */ 36 return ACCESS_ONCE(file->private_data); 37 } 38 39 static void fuse_request_init(struct fuse_req *req, struct page **pages, 40 struct fuse_page_desc *page_descs, 41 unsigned npages) 42 { 43 memset(req, 0, sizeof(*req)); 44 memset(pages, 0, sizeof(*pages) * npages); 45 memset(page_descs, 0, sizeof(*page_descs) * npages); 46 INIT_LIST_HEAD(&req->list); 47 INIT_LIST_HEAD(&req->intr_entry); 48 init_waitqueue_head(&req->waitq); 49 refcount_set(&req->count, 1); 50 req->pages = pages; 51 req->page_descs = page_descs; 52 req->max_pages = npages; 53 __set_bit(FR_PENDING, &req->flags); 54 } 55 56 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags) 57 { 58 struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags); 59 if (req) { 60 struct page **pages; 61 struct fuse_page_desc *page_descs; 62 63 if (npages <= FUSE_REQ_INLINE_PAGES) { 64 pages = req->inline_pages; 65 page_descs = req->inline_page_descs; 66 } else { 67 pages = kmalloc(sizeof(struct page *) * npages, flags); 68 page_descs = kmalloc(sizeof(struct fuse_page_desc) * 69 npages, flags); 70 } 71 72 if (!pages || !page_descs) { 73 kfree(pages); 74 kfree(page_descs); 75 kmem_cache_free(fuse_req_cachep, req); 76 return NULL; 77 } 78 79 fuse_request_init(req, pages, page_descs, npages); 80 } 81 return req; 82 } 83 84 struct fuse_req *fuse_request_alloc(unsigned npages) 85 { 86 return __fuse_request_alloc(npages, GFP_KERNEL); 87 } 88 EXPORT_SYMBOL_GPL(fuse_request_alloc); 89 90 struct fuse_req *fuse_request_alloc_nofs(unsigned npages) 91 { 92 return __fuse_request_alloc(npages, GFP_NOFS); 93 } 94 95 void fuse_request_free(struct fuse_req *req) 96 { 97 if (req->pages != req->inline_pages) { 98 kfree(req->pages); 99 kfree(req->page_descs); 100 } 101 kmem_cache_free(fuse_req_cachep, req); 102 } 103 104 void __fuse_get_request(struct fuse_req *req) 105 { 106 refcount_inc(&req->count); 107 } 108 109 /* Must be called with > 1 refcount */ 110 static void __fuse_put_request(struct fuse_req *req) 111 { 112 refcount_dec(&req->count); 113 } 114 115 static void fuse_req_init_context(struct fuse_conn *fc, struct fuse_req *req) 116 { 117 req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid()); 118 req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid()); 119 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 120 } 121 122 void fuse_set_initialized(struct fuse_conn *fc) 123 { 124 /* Make sure stores before this are seen on another CPU */ 125 smp_wmb(); 126 fc->initialized = 1; 127 } 128 129 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 130 { 131 return !fc->initialized || (for_background && fc->blocked); 132 } 133 134 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages, 135 bool for_background) 136 { 137 struct fuse_req *req; 138 int err; 139 atomic_inc(&fc->num_waiting); 140 141 if (fuse_block_alloc(fc, for_background)) { 142 err = -EINTR; 143 if (wait_event_killable_exclusive(fc->blocked_waitq, 144 !fuse_block_alloc(fc, for_background))) 145 goto out; 146 } 147 /* Matches smp_wmb() in fuse_set_initialized() */ 148 smp_rmb(); 149 150 err = -ENOTCONN; 151 if (!fc->connected) 152 goto out; 153 154 err = -ECONNREFUSED; 155 if (fc->conn_error) 156 goto out; 157 158 req = fuse_request_alloc(npages); 159 err = -ENOMEM; 160 if (!req) { 161 if (for_background) 162 wake_up(&fc->blocked_waitq); 163 goto out; 164 } 165 166 fuse_req_init_context(fc, req); 167 __set_bit(FR_WAITING, &req->flags); 168 if (for_background) 169 __set_bit(FR_BACKGROUND, &req->flags); 170 171 return req; 172 173 out: 174 atomic_dec(&fc->num_waiting); 175 return ERR_PTR(err); 176 } 177 178 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages) 179 { 180 return __fuse_get_req(fc, npages, false); 181 } 182 EXPORT_SYMBOL_GPL(fuse_get_req); 183 184 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc, 185 unsigned npages) 186 { 187 return __fuse_get_req(fc, npages, true); 188 } 189 EXPORT_SYMBOL_GPL(fuse_get_req_for_background); 190 191 /* 192 * Return request in fuse_file->reserved_req. However that may 193 * currently be in use. If that is the case, wait for it to become 194 * available. 195 */ 196 static struct fuse_req *get_reserved_req(struct fuse_conn *fc, 197 struct file *file) 198 { 199 struct fuse_req *req = NULL; 200 struct fuse_file *ff = file->private_data; 201 202 do { 203 wait_event(fc->reserved_req_waitq, ff->reserved_req); 204 spin_lock(&fc->lock); 205 if (ff->reserved_req) { 206 req = ff->reserved_req; 207 ff->reserved_req = NULL; 208 req->stolen_file = get_file(file); 209 } 210 spin_unlock(&fc->lock); 211 } while (!req); 212 213 return req; 214 } 215 216 /* 217 * Put stolen request back into fuse_file->reserved_req 218 */ 219 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req) 220 { 221 struct file *file = req->stolen_file; 222 struct fuse_file *ff = file->private_data; 223 224 spin_lock(&fc->lock); 225 fuse_request_init(req, req->pages, req->page_descs, req->max_pages); 226 BUG_ON(ff->reserved_req); 227 ff->reserved_req = req; 228 wake_up_all(&fc->reserved_req_waitq); 229 spin_unlock(&fc->lock); 230 fput(file); 231 } 232 233 /* 234 * Gets a requests for a file operation, always succeeds 235 * 236 * This is used for sending the FLUSH request, which must get to 237 * userspace, due to POSIX locks which may need to be unlocked. 238 * 239 * If allocation fails due to OOM, use the reserved request in 240 * fuse_file. 241 * 242 * This is very unlikely to deadlock accidentally, since the 243 * filesystem should not have it's own file open. If deadlock is 244 * intentional, it can still be broken by "aborting" the filesystem. 245 */ 246 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc, 247 struct file *file) 248 { 249 struct fuse_req *req; 250 251 atomic_inc(&fc->num_waiting); 252 wait_event(fc->blocked_waitq, fc->initialized); 253 /* Matches smp_wmb() in fuse_set_initialized() */ 254 smp_rmb(); 255 req = fuse_request_alloc(0); 256 if (!req) 257 req = get_reserved_req(fc, file); 258 259 fuse_req_init_context(fc, req); 260 __set_bit(FR_WAITING, &req->flags); 261 __clear_bit(FR_BACKGROUND, &req->flags); 262 return req; 263 } 264 265 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) 266 { 267 if (refcount_dec_and_test(&req->count)) { 268 if (test_bit(FR_BACKGROUND, &req->flags)) { 269 /* 270 * We get here in the unlikely case that a background 271 * request was allocated but not sent 272 */ 273 spin_lock(&fc->lock); 274 if (!fc->blocked) 275 wake_up(&fc->blocked_waitq); 276 spin_unlock(&fc->lock); 277 } 278 279 if (test_bit(FR_WAITING, &req->flags)) { 280 __clear_bit(FR_WAITING, &req->flags); 281 atomic_dec(&fc->num_waiting); 282 } 283 284 if (req->stolen_file) 285 put_reserved_req(fc, req); 286 else 287 fuse_request_free(req); 288 } 289 } 290 EXPORT_SYMBOL_GPL(fuse_put_request); 291 292 static unsigned len_args(unsigned numargs, struct fuse_arg *args) 293 { 294 unsigned nbytes = 0; 295 unsigned i; 296 297 for (i = 0; i < numargs; i++) 298 nbytes += args[i].size; 299 300 return nbytes; 301 } 302 303 static u64 fuse_get_unique(struct fuse_iqueue *fiq) 304 { 305 return ++fiq->reqctr; 306 } 307 308 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req) 309 { 310 req->in.h.len = sizeof(struct fuse_in_header) + 311 len_args(req->in.numargs, (struct fuse_arg *) req->in.args); 312 list_add_tail(&req->list, &fiq->pending); 313 wake_up_locked(&fiq->waitq); 314 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 315 } 316 317 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 318 u64 nodeid, u64 nlookup) 319 { 320 struct fuse_iqueue *fiq = &fc->iq; 321 322 forget->forget_one.nodeid = nodeid; 323 forget->forget_one.nlookup = nlookup; 324 325 spin_lock(&fiq->waitq.lock); 326 if (fiq->connected) { 327 fiq->forget_list_tail->next = forget; 328 fiq->forget_list_tail = forget; 329 wake_up_locked(&fiq->waitq); 330 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 331 } else { 332 kfree(forget); 333 } 334 spin_unlock(&fiq->waitq.lock); 335 } 336 337 static void flush_bg_queue(struct fuse_conn *fc) 338 { 339 while (fc->active_background < fc->max_background && 340 !list_empty(&fc->bg_queue)) { 341 struct fuse_req *req; 342 struct fuse_iqueue *fiq = &fc->iq; 343 344 req = list_entry(fc->bg_queue.next, struct fuse_req, list); 345 list_del(&req->list); 346 fc->active_background++; 347 spin_lock(&fiq->waitq.lock); 348 req->in.h.unique = fuse_get_unique(fiq); 349 queue_request(fiq, req); 350 spin_unlock(&fiq->waitq.lock); 351 } 352 } 353 354 /* 355 * This function is called when a request is finished. Either a reply 356 * has arrived or it was aborted (and not yet sent) or some error 357 * occurred during communication with userspace, or the device file 358 * was closed. The requester thread is woken up (if still waiting), 359 * the 'end' callback is called if given, else the reference to the 360 * request is released 361 */ 362 static void request_end(struct fuse_conn *fc, struct fuse_req *req) 363 { 364 struct fuse_iqueue *fiq = &fc->iq; 365 366 if (test_and_set_bit(FR_FINISHED, &req->flags)) 367 return; 368 369 spin_lock(&fiq->waitq.lock); 370 list_del_init(&req->intr_entry); 371 spin_unlock(&fiq->waitq.lock); 372 WARN_ON(test_bit(FR_PENDING, &req->flags)); 373 WARN_ON(test_bit(FR_SENT, &req->flags)); 374 if (test_bit(FR_BACKGROUND, &req->flags)) { 375 spin_lock(&fc->lock); 376 clear_bit(FR_BACKGROUND, &req->flags); 377 if (fc->num_background == fc->max_background) 378 fc->blocked = 0; 379 380 /* Wake up next waiter, if any */ 381 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq)) 382 wake_up(&fc->blocked_waitq); 383 384 if (fc->num_background == fc->congestion_threshold && 385 fc->connected && fc->sb) { 386 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 387 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 388 } 389 fc->num_background--; 390 fc->active_background--; 391 flush_bg_queue(fc); 392 spin_unlock(&fc->lock); 393 } 394 wake_up(&req->waitq); 395 if (req->end) 396 req->end(fc, req); 397 fuse_put_request(fc, req); 398 } 399 400 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) 401 { 402 spin_lock(&fiq->waitq.lock); 403 if (test_bit(FR_FINISHED, &req->flags)) { 404 spin_unlock(&fiq->waitq.lock); 405 return; 406 } 407 if (list_empty(&req->intr_entry)) { 408 list_add_tail(&req->intr_entry, &fiq->interrupts); 409 wake_up_locked(&fiq->waitq); 410 } 411 spin_unlock(&fiq->waitq.lock); 412 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 413 } 414 415 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) 416 { 417 struct fuse_iqueue *fiq = &fc->iq; 418 int err; 419 420 if (!fc->no_interrupt) { 421 /* Any signal may interrupt this */ 422 err = wait_event_interruptible(req->waitq, 423 test_bit(FR_FINISHED, &req->flags)); 424 if (!err) 425 return; 426 427 set_bit(FR_INTERRUPTED, &req->flags); 428 /* matches barrier in fuse_dev_do_read() */ 429 smp_mb__after_atomic(); 430 if (test_bit(FR_SENT, &req->flags)) 431 queue_interrupt(fiq, req); 432 } 433 434 if (!test_bit(FR_FORCE, &req->flags)) { 435 /* Only fatal signals may interrupt this */ 436 err = wait_event_killable(req->waitq, 437 test_bit(FR_FINISHED, &req->flags)); 438 if (!err) 439 return; 440 441 spin_lock(&fiq->waitq.lock); 442 /* Request is not yet in userspace, bail out */ 443 if (test_bit(FR_PENDING, &req->flags)) { 444 list_del(&req->list); 445 spin_unlock(&fiq->waitq.lock); 446 __fuse_put_request(req); 447 req->out.h.error = -EINTR; 448 return; 449 } 450 spin_unlock(&fiq->waitq.lock); 451 } 452 453 /* 454 * Either request is already in userspace, or it was forced. 455 * Wait it out. 456 */ 457 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags)); 458 } 459 460 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 461 { 462 struct fuse_iqueue *fiq = &fc->iq; 463 464 BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); 465 spin_lock(&fiq->waitq.lock); 466 if (!fiq->connected) { 467 spin_unlock(&fiq->waitq.lock); 468 req->out.h.error = -ENOTCONN; 469 } else { 470 req->in.h.unique = fuse_get_unique(fiq); 471 queue_request(fiq, req); 472 /* acquire extra reference, since request is still needed 473 after request_end() */ 474 __fuse_get_request(req); 475 spin_unlock(&fiq->waitq.lock); 476 477 request_wait_answer(fc, req); 478 /* Pairs with smp_wmb() in request_end() */ 479 smp_rmb(); 480 } 481 } 482 483 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 484 { 485 __set_bit(FR_ISREPLY, &req->flags); 486 if (!test_bit(FR_WAITING, &req->flags)) { 487 __set_bit(FR_WAITING, &req->flags); 488 atomic_inc(&fc->num_waiting); 489 } 490 __fuse_request_send(fc, req); 491 } 492 EXPORT_SYMBOL_GPL(fuse_request_send); 493 494 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) 495 { 496 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS) 497 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE; 498 499 if (fc->minor < 9) { 500 switch (args->in.h.opcode) { 501 case FUSE_LOOKUP: 502 case FUSE_CREATE: 503 case FUSE_MKNOD: 504 case FUSE_MKDIR: 505 case FUSE_SYMLINK: 506 case FUSE_LINK: 507 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; 508 break; 509 case FUSE_GETATTR: 510 case FUSE_SETATTR: 511 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; 512 break; 513 } 514 } 515 if (fc->minor < 12) { 516 switch (args->in.h.opcode) { 517 case FUSE_CREATE: 518 args->in.args[0].size = sizeof(struct fuse_open_in); 519 break; 520 case FUSE_MKNOD: 521 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; 522 break; 523 } 524 } 525 } 526 527 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) 528 { 529 struct fuse_req *req; 530 ssize_t ret; 531 532 req = fuse_get_req(fc, 0); 533 if (IS_ERR(req)) 534 return PTR_ERR(req); 535 536 /* Needs to be done after fuse_get_req() so that fc->minor is valid */ 537 fuse_adjust_compat(fc, args); 538 539 req->in.h.opcode = args->in.h.opcode; 540 req->in.h.nodeid = args->in.h.nodeid; 541 req->in.numargs = args->in.numargs; 542 memcpy(req->in.args, args->in.args, 543 args->in.numargs * sizeof(struct fuse_in_arg)); 544 req->out.argvar = args->out.argvar; 545 req->out.numargs = args->out.numargs; 546 memcpy(req->out.args, args->out.args, 547 args->out.numargs * sizeof(struct fuse_arg)); 548 fuse_request_send(fc, req); 549 ret = req->out.h.error; 550 if (!ret && args->out.argvar) { 551 BUG_ON(args->out.numargs != 1); 552 ret = req->out.args[0].size; 553 } 554 fuse_put_request(fc, req); 555 556 return ret; 557 } 558 559 /* 560 * Called under fc->lock 561 * 562 * fc->connected must have been checked previously 563 */ 564 void fuse_request_send_background_locked(struct fuse_conn *fc, 565 struct fuse_req *req) 566 { 567 BUG_ON(!test_bit(FR_BACKGROUND, &req->flags)); 568 if (!test_bit(FR_WAITING, &req->flags)) { 569 __set_bit(FR_WAITING, &req->flags); 570 atomic_inc(&fc->num_waiting); 571 } 572 __set_bit(FR_ISREPLY, &req->flags); 573 fc->num_background++; 574 if (fc->num_background == fc->max_background) 575 fc->blocked = 1; 576 if (fc->num_background == fc->congestion_threshold && fc->sb) { 577 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 578 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 579 } 580 list_add_tail(&req->list, &fc->bg_queue); 581 flush_bg_queue(fc); 582 } 583 584 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) 585 { 586 BUG_ON(!req->end); 587 spin_lock(&fc->lock); 588 if (fc->connected) { 589 fuse_request_send_background_locked(fc, req); 590 spin_unlock(&fc->lock); 591 } else { 592 spin_unlock(&fc->lock); 593 req->out.h.error = -ENOTCONN; 594 req->end(fc, req); 595 fuse_put_request(fc, req); 596 } 597 } 598 EXPORT_SYMBOL_GPL(fuse_request_send_background); 599 600 static int fuse_request_send_notify_reply(struct fuse_conn *fc, 601 struct fuse_req *req, u64 unique) 602 { 603 int err = -ENODEV; 604 struct fuse_iqueue *fiq = &fc->iq; 605 606 __clear_bit(FR_ISREPLY, &req->flags); 607 req->in.h.unique = unique; 608 spin_lock(&fiq->waitq.lock); 609 if (fiq->connected) { 610 queue_request(fiq, req); 611 err = 0; 612 } 613 spin_unlock(&fiq->waitq.lock); 614 615 return err; 616 } 617 618 void fuse_force_forget(struct file *file, u64 nodeid) 619 { 620 struct inode *inode = file_inode(file); 621 struct fuse_conn *fc = get_fuse_conn(inode); 622 struct fuse_req *req; 623 struct fuse_forget_in inarg; 624 625 memset(&inarg, 0, sizeof(inarg)); 626 inarg.nlookup = 1; 627 req = fuse_get_req_nofail_nopages(fc, file); 628 req->in.h.opcode = FUSE_FORGET; 629 req->in.h.nodeid = nodeid; 630 req->in.numargs = 1; 631 req->in.args[0].size = sizeof(inarg); 632 req->in.args[0].value = &inarg; 633 __clear_bit(FR_ISREPLY, &req->flags); 634 __fuse_request_send(fc, req); 635 /* ignore errors */ 636 fuse_put_request(fc, req); 637 } 638 639 /* 640 * Lock the request. Up to the next unlock_request() there mustn't be 641 * anything that could cause a page-fault. If the request was already 642 * aborted bail out. 643 */ 644 static int lock_request(struct fuse_req *req) 645 { 646 int err = 0; 647 if (req) { 648 spin_lock(&req->waitq.lock); 649 if (test_bit(FR_ABORTED, &req->flags)) 650 err = -ENOENT; 651 else 652 set_bit(FR_LOCKED, &req->flags); 653 spin_unlock(&req->waitq.lock); 654 } 655 return err; 656 } 657 658 /* 659 * Unlock request. If it was aborted while locked, caller is responsible 660 * for unlocking and ending the request. 661 */ 662 static int unlock_request(struct fuse_req *req) 663 { 664 int err = 0; 665 if (req) { 666 spin_lock(&req->waitq.lock); 667 if (test_bit(FR_ABORTED, &req->flags)) 668 err = -ENOENT; 669 else 670 clear_bit(FR_LOCKED, &req->flags); 671 spin_unlock(&req->waitq.lock); 672 } 673 return err; 674 } 675 676 struct fuse_copy_state { 677 int write; 678 struct fuse_req *req; 679 struct iov_iter *iter; 680 struct pipe_buffer *pipebufs; 681 struct pipe_buffer *currbuf; 682 struct pipe_inode_info *pipe; 683 unsigned long nr_segs; 684 struct page *pg; 685 unsigned len; 686 unsigned offset; 687 unsigned move_pages:1; 688 }; 689 690 static void fuse_copy_init(struct fuse_copy_state *cs, int write, 691 struct iov_iter *iter) 692 { 693 memset(cs, 0, sizeof(*cs)); 694 cs->write = write; 695 cs->iter = iter; 696 } 697 698 /* Unmap and put previous page of userspace buffer */ 699 static void fuse_copy_finish(struct fuse_copy_state *cs) 700 { 701 if (cs->currbuf) { 702 struct pipe_buffer *buf = cs->currbuf; 703 704 if (cs->write) 705 buf->len = PAGE_SIZE - cs->len; 706 cs->currbuf = NULL; 707 } else if (cs->pg) { 708 if (cs->write) { 709 flush_dcache_page(cs->pg); 710 set_page_dirty_lock(cs->pg); 711 } 712 put_page(cs->pg); 713 } 714 cs->pg = NULL; 715 } 716 717 /* 718 * Get another pagefull of userspace buffer, and map it to kernel 719 * address space, and lock request 720 */ 721 static int fuse_copy_fill(struct fuse_copy_state *cs) 722 { 723 struct page *page; 724 int err; 725 726 err = unlock_request(cs->req); 727 if (err) 728 return err; 729 730 fuse_copy_finish(cs); 731 if (cs->pipebufs) { 732 struct pipe_buffer *buf = cs->pipebufs; 733 734 if (!cs->write) { 735 err = pipe_buf_confirm(cs->pipe, buf); 736 if (err) 737 return err; 738 739 BUG_ON(!cs->nr_segs); 740 cs->currbuf = buf; 741 cs->pg = buf->page; 742 cs->offset = buf->offset; 743 cs->len = buf->len; 744 cs->pipebufs++; 745 cs->nr_segs--; 746 } else { 747 if (cs->nr_segs == cs->pipe->buffers) 748 return -EIO; 749 750 page = alloc_page(GFP_HIGHUSER); 751 if (!page) 752 return -ENOMEM; 753 754 buf->page = page; 755 buf->offset = 0; 756 buf->len = 0; 757 758 cs->currbuf = buf; 759 cs->pg = page; 760 cs->offset = 0; 761 cs->len = PAGE_SIZE; 762 cs->pipebufs++; 763 cs->nr_segs++; 764 } 765 } else { 766 size_t off; 767 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off); 768 if (err < 0) 769 return err; 770 BUG_ON(!err); 771 cs->len = err; 772 cs->offset = off; 773 cs->pg = page; 774 iov_iter_advance(cs->iter, err); 775 } 776 777 return lock_request(cs->req); 778 } 779 780 /* Do as much copy to/from userspace buffer as we can */ 781 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 782 { 783 unsigned ncpy = min(*size, cs->len); 784 if (val) { 785 void *pgaddr = kmap_atomic(cs->pg); 786 void *buf = pgaddr + cs->offset; 787 788 if (cs->write) 789 memcpy(buf, *val, ncpy); 790 else 791 memcpy(*val, buf, ncpy); 792 793 kunmap_atomic(pgaddr); 794 *val += ncpy; 795 } 796 *size -= ncpy; 797 cs->len -= ncpy; 798 cs->offset += ncpy; 799 return ncpy; 800 } 801 802 static int fuse_check_page(struct page *page) 803 { 804 if (page_mapcount(page) || 805 page->mapping != NULL || 806 page_count(page) != 1 || 807 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 808 ~(1 << PG_locked | 809 1 << PG_referenced | 810 1 << PG_uptodate | 811 1 << PG_lru | 812 1 << PG_active | 813 1 << PG_reclaim))) { 814 printk(KERN_WARNING "fuse: trying to steal weird page\n"); 815 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); 816 return 1; 817 } 818 return 0; 819 } 820 821 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 822 { 823 int err; 824 struct page *oldpage = *pagep; 825 struct page *newpage; 826 struct pipe_buffer *buf = cs->pipebufs; 827 828 err = unlock_request(cs->req); 829 if (err) 830 return err; 831 832 fuse_copy_finish(cs); 833 834 err = pipe_buf_confirm(cs->pipe, buf); 835 if (err) 836 return err; 837 838 BUG_ON(!cs->nr_segs); 839 cs->currbuf = buf; 840 cs->len = buf->len; 841 cs->pipebufs++; 842 cs->nr_segs--; 843 844 if (cs->len != PAGE_SIZE) 845 goto out_fallback; 846 847 if (pipe_buf_steal(cs->pipe, buf) != 0) 848 goto out_fallback; 849 850 newpage = buf->page; 851 852 if (!PageUptodate(newpage)) 853 SetPageUptodate(newpage); 854 855 ClearPageMappedToDisk(newpage); 856 857 if (fuse_check_page(newpage) != 0) 858 goto out_fallback_unlock; 859 860 /* 861 * This is a new and locked page, it shouldn't be mapped or 862 * have any special flags on it 863 */ 864 if (WARN_ON(page_mapped(oldpage))) 865 goto out_fallback_unlock; 866 if (WARN_ON(page_has_private(oldpage))) 867 goto out_fallback_unlock; 868 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 869 goto out_fallback_unlock; 870 if (WARN_ON(PageMlocked(oldpage))) 871 goto out_fallback_unlock; 872 873 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); 874 if (err) { 875 unlock_page(newpage); 876 return err; 877 } 878 879 get_page(newpage); 880 881 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 882 lru_cache_add_file(newpage); 883 884 err = 0; 885 spin_lock(&cs->req->waitq.lock); 886 if (test_bit(FR_ABORTED, &cs->req->flags)) 887 err = -ENOENT; 888 else 889 *pagep = newpage; 890 spin_unlock(&cs->req->waitq.lock); 891 892 if (err) { 893 unlock_page(newpage); 894 put_page(newpage); 895 return err; 896 } 897 898 unlock_page(oldpage); 899 put_page(oldpage); 900 cs->len = 0; 901 902 return 0; 903 904 out_fallback_unlock: 905 unlock_page(newpage); 906 out_fallback: 907 cs->pg = buf->page; 908 cs->offset = buf->offset; 909 910 err = lock_request(cs->req); 911 if (err) 912 return err; 913 914 return 1; 915 } 916 917 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 918 unsigned offset, unsigned count) 919 { 920 struct pipe_buffer *buf; 921 int err; 922 923 if (cs->nr_segs == cs->pipe->buffers) 924 return -EIO; 925 926 err = unlock_request(cs->req); 927 if (err) 928 return err; 929 930 fuse_copy_finish(cs); 931 932 buf = cs->pipebufs; 933 get_page(page); 934 buf->page = page; 935 buf->offset = offset; 936 buf->len = count; 937 938 cs->pipebufs++; 939 cs->nr_segs++; 940 cs->len = 0; 941 942 return 0; 943 } 944 945 /* 946 * Copy a page in the request to/from the userspace buffer. Must be 947 * done atomically 948 */ 949 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 950 unsigned offset, unsigned count, int zeroing) 951 { 952 int err; 953 struct page *page = *pagep; 954 955 if (page && zeroing && count < PAGE_SIZE) 956 clear_highpage(page); 957 958 while (count) { 959 if (cs->write && cs->pipebufs && page) { 960 return fuse_ref_page(cs, page, offset, count); 961 } else if (!cs->len) { 962 if (cs->move_pages && page && 963 offset == 0 && count == PAGE_SIZE) { 964 err = fuse_try_move_page(cs, pagep); 965 if (err <= 0) 966 return err; 967 } else { 968 err = fuse_copy_fill(cs); 969 if (err) 970 return err; 971 } 972 } 973 if (page) { 974 void *mapaddr = kmap_atomic(page); 975 void *buf = mapaddr + offset; 976 offset += fuse_copy_do(cs, &buf, &count); 977 kunmap_atomic(mapaddr); 978 } else 979 offset += fuse_copy_do(cs, NULL, &count); 980 } 981 if (page && !cs->write) 982 flush_dcache_page(page); 983 return 0; 984 } 985 986 /* Copy pages in the request to/from userspace buffer */ 987 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 988 int zeroing) 989 { 990 unsigned i; 991 struct fuse_req *req = cs->req; 992 993 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { 994 int err; 995 unsigned offset = req->page_descs[i].offset; 996 unsigned count = min(nbytes, req->page_descs[i].length); 997 998 err = fuse_copy_page(cs, &req->pages[i], offset, count, 999 zeroing); 1000 if (err) 1001 return err; 1002 1003 nbytes -= count; 1004 } 1005 return 0; 1006 } 1007 1008 /* Copy a single argument in the request to/from userspace buffer */ 1009 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 1010 { 1011 while (size) { 1012 if (!cs->len) { 1013 int err = fuse_copy_fill(cs); 1014 if (err) 1015 return err; 1016 } 1017 fuse_copy_do(cs, &val, &size); 1018 } 1019 return 0; 1020 } 1021 1022 /* Copy request arguments to/from userspace buffer */ 1023 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1024 unsigned argpages, struct fuse_arg *args, 1025 int zeroing) 1026 { 1027 int err = 0; 1028 unsigned i; 1029 1030 for (i = 0; !err && i < numargs; i++) { 1031 struct fuse_arg *arg = &args[i]; 1032 if (i == numargs - 1 && argpages) 1033 err = fuse_copy_pages(cs, arg->size, zeroing); 1034 else 1035 err = fuse_copy_one(cs, arg->value, arg->size); 1036 } 1037 return err; 1038 } 1039 1040 static int forget_pending(struct fuse_iqueue *fiq) 1041 { 1042 return fiq->forget_list_head.next != NULL; 1043 } 1044 1045 static int request_pending(struct fuse_iqueue *fiq) 1046 { 1047 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1048 forget_pending(fiq); 1049 } 1050 1051 /* 1052 * Transfer an interrupt request to userspace 1053 * 1054 * Unlike other requests this is assembled on demand, without a need 1055 * to allocate a separate fuse_req structure. 1056 * 1057 * Called with fiq->waitq.lock held, releases it 1058 */ 1059 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1060 struct fuse_copy_state *cs, 1061 size_t nbytes, struct fuse_req *req) 1062 __releases(fiq->waitq.lock) 1063 { 1064 struct fuse_in_header ih; 1065 struct fuse_interrupt_in arg; 1066 unsigned reqsize = sizeof(ih) + sizeof(arg); 1067 int err; 1068 1069 list_del_init(&req->intr_entry); 1070 req->intr_unique = fuse_get_unique(fiq); 1071 memset(&ih, 0, sizeof(ih)); 1072 memset(&arg, 0, sizeof(arg)); 1073 ih.len = reqsize; 1074 ih.opcode = FUSE_INTERRUPT; 1075 ih.unique = req->intr_unique; 1076 arg.unique = req->in.h.unique; 1077 1078 spin_unlock(&fiq->waitq.lock); 1079 if (nbytes < reqsize) 1080 return -EINVAL; 1081 1082 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1083 if (!err) 1084 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1085 fuse_copy_finish(cs); 1086 1087 return err ? err : reqsize; 1088 } 1089 1090 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq, 1091 unsigned max, 1092 unsigned *countp) 1093 { 1094 struct fuse_forget_link *head = fiq->forget_list_head.next; 1095 struct fuse_forget_link **newhead = &head; 1096 unsigned count; 1097 1098 for (count = 0; *newhead != NULL && count < max; count++) 1099 newhead = &(*newhead)->next; 1100 1101 fiq->forget_list_head.next = *newhead; 1102 *newhead = NULL; 1103 if (fiq->forget_list_head.next == NULL) 1104 fiq->forget_list_tail = &fiq->forget_list_head; 1105 1106 if (countp != NULL) 1107 *countp = count; 1108 1109 return head; 1110 } 1111 1112 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1113 struct fuse_copy_state *cs, 1114 size_t nbytes) 1115 __releases(fiq->waitq.lock) 1116 { 1117 int err; 1118 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL); 1119 struct fuse_forget_in arg = { 1120 .nlookup = forget->forget_one.nlookup, 1121 }; 1122 struct fuse_in_header ih = { 1123 .opcode = FUSE_FORGET, 1124 .nodeid = forget->forget_one.nodeid, 1125 .unique = fuse_get_unique(fiq), 1126 .len = sizeof(ih) + sizeof(arg), 1127 }; 1128 1129 spin_unlock(&fiq->waitq.lock); 1130 kfree(forget); 1131 if (nbytes < ih.len) 1132 return -EINVAL; 1133 1134 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1135 if (!err) 1136 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1137 fuse_copy_finish(cs); 1138 1139 if (err) 1140 return err; 1141 1142 return ih.len; 1143 } 1144 1145 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1146 struct fuse_copy_state *cs, size_t nbytes) 1147 __releases(fiq->waitq.lock) 1148 { 1149 int err; 1150 unsigned max_forgets; 1151 unsigned count; 1152 struct fuse_forget_link *head; 1153 struct fuse_batch_forget_in arg = { .count = 0 }; 1154 struct fuse_in_header ih = { 1155 .opcode = FUSE_BATCH_FORGET, 1156 .unique = fuse_get_unique(fiq), 1157 .len = sizeof(ih) + sizeof(arg), 1158 }; 1159 1160 if (nbytes < ih.len) { 1161 spin_unlock(&fiq->waitq.lock); 1162 return -EINVAL; 1163 } 1164 1165 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1166 head = dequeue_forget(fiq, max_forgets, &count); 1167 spin_unlock(&fiq->waitq.lock); 1168 1169 arg.count = count; 1170 ih.len += count * sizeof(struct fuse_forget_one); 1171 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1172 if (!err) 1173 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1174 1175 while (head) { 1176 struct fuse_forget_link *forget = head; 1177 1178 if (!err) { 1179 err = fuse_copy_one(cs, &forget->forget_one, 1180 sizeof(forget->forget_one)); 1181 } 1182 head = forget->next; 1183 kfree(forget); 1184 } 1185 1186 fuse_copy_finish(cs); 1187 1188 if (err) 1189 return err; 1190 1191 return ih.len; 1192 } 1193 1194 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1195 struct fuse_copy_state *cs, 1196 size_t nbytes) 1197 __releases(fiq->waitq.lock) 1198 { 1199 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1200 return fuse_read_single_forget(fiq, cs, nbytes); 1201 else 1202 return fuse_read_batch_forget(fiq, cs, nbytes); 1203 } 1204 1205 /* 1206 * Read a single request into the userspace filesystem's buffer. This 1207 * function waits until a request is available, then removes it from 1208 * the pending list and copies request data to userspace buffer. If 1209 * no reply is needed (FORGET) or request has been aborted or there 1210 * was an error during the copying then it's finished by calling 1211 * request_end(). Otherwise add it to the processing list, and set 1212 * the 'sent' flag. 1213 */ 1214 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1215 struct fuse_copy_state *cs, size_t nbytes) 1216 { 1217 ssize_t err; 1218 struct fuse_conn *fc = fud->fc; 1219 struct fuse_iqueue *fiq = &fc->iq; 1220 struct fuse_pqueue *fpq = &fud->pq; 1221 struct fuse_req *req; 1222 struct fuse_in *in; 1223 unsigned reqsize; 1224 1225 if (task_active_pid_ns(current) != fc->pid_ns) 1226 return -EIO; 1227 1228 restart: 1229 spin_lock(&fiq->waitq.lock); 1230 err = -EAGAIN; 1231 if ((file->f_flags & O_NONBLOCK) && fiq->connected && 1232 !request_pending(fiq)) 1233 goto err_unlock; 1234 1235 err = wait_event_interruptible_exclusive_locked(fiq->waitq, 1236 !fiq->connected || request_pending(fiq)); 1237 if (err) 1238 goto err_unlock; 1239 1240 err = -ENODEV; 1241 if (!fiq->connected) 1242 goto err_unlock; 1243 1244 if (!list_empty(&fiq->interrupts)) { 1245 req = list_entry(fiq->interrupts.next, struct fuse_req, 1246 intr_entry); 1247 return fuse_read_interrupt(fiq, cs, nbytes, req); 1248 } 1249 1250 if (forget_pending(fiq)) { 1251 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1252 return fuse_read_forget(fc, fiq, cs, nbytes); 1253 1254 if (fiq->forget_batch <= -8) 1255 fiq->forget_batch = 16; 1256 } 1257 1258 req = list_entry(fiq->pending.next, struct fuse_req, list); 1259 clear_bit(FR_PENDING, &req->flags); 1260 list_del_init(&req->list); 1261 spin_unlock(&fiq->waitq.lock); 1262 1263 in = &req->in; 1264 reqsize = in->h.len; 1265 /* If request is too large, reply with an error and restart the read */ 1266 if (nbytes < reqsize) { 1267 req->out.h.error = -EIO; 1268 /* SETXATTR is special, since it may contain too large data */ 1269 if (in->h.opcode == FUSE_SETXATTR) 1270 req->out.h.error = -E2BIG; 1271 request_end(fc, req); 1272 goto restart; 1273 } 1274 spin_lock(&fpq->lock); 1275 list_add(&req->list, &fpq->io); 1276 spin_unlock(&fpq->lock); 1277 cs->req = req; 1278 err = fuse_copy_one(cs, &in->h, sizeof(in->h)); 1279 if (!err) 1280 err = fuse_copy_args(cs, in->numargs, in->argpages, 1281 (struct fuse_arg *) in->args, 0); 1282 fuse_copy_finish(cs); 1283 spin_lock(&fpq->lock); 1284 clear_bit(FR_LOCKED, &req->flags); 1285 if (!fpq->connected) { 1286 err = -ENODEV; 1287 goto out_end; 1288 } 1289 if (err) { 1290 req->out.h.error = -EIO; 1291 goto out_end; 1292 } 1293 if (!test_bit(FR_ISREPLY, &req->flags)) { 1294 err = reqsize; 1295 goto out_end; 1296 } 1297 list_move_tail(&req->list, &fpq->processing); 1298 spin_unlock(&fpq->lock); 1299 set_bit(FR_SENT, &req->flags); 1300 /* matches barrier in request_wait_answer() */ 1301 smp_mb__after_atomic(); 1302 if (test_bit(FR_INTERRUPTED, &req->flags)) 1303 queue_interrupt(fiq, req); 1304 1305 return reqsize; 1306 1307 out_end: 1308 if (!test_bit(FR_PRIVATE, &req->flags)) 1309 list_del_init(&req->list); 1310 spin_unlock(&fpq->lock); 1311 request_end(fc, req); 1312 return err; 1313 1314 err_unlock: 1315 spin_unlock(&fiq->waitq.lock); 1316 return err; 1317 } 1318 1319 static int fuse_dev_open(struct inode *inode, struct file *file) 1320 { 1321 /* 1322 * The fuse device's file's private_data is used to hold 1323 * the fuse_conn(ection) when it is mounted, and is used to 1324 * keep track of whether the file has been mounted already. 1325 */ 1326 file->private_data = NULL; 1327 return 0; 1328 } 1329 1330 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1331 { 1332 struct fuse_copy_state cs; 1333 struct file *file = iocb->ki_filp; 1334 struct fuse_dev *fud = fuse_get_dev(file); 1335 1336 if (!fud) 1337 return -EPERM; 1338 1339 if (!iter_is_iovec(to)) 1340 return -EINVAL; 1341 1342 fuse_copy_init(&cs, 1, to); 1343 1344 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1345 } 1346 1347 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1348 struct pipe_inode_info *pipe, 1349 size_t len, unsigned int flags) 1350 { 1351 int total, ret; 1352 int page_nr = 0; 1353 struct pipe_buffer *bufs; 1354 struct fuse_copy_state cs; 1355 struct fuse_dev *fud = fuse_get_dev(in); 1356 1357 if (!fud) 1358 return -EPERM; 1359 1360 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1361 if (!bufs) 1362 return -ENOMEM; 1363 1364 fuse_copy_init(&cs, 1, NULL); 1365 cs.pipebufs = bufs; 1366 cs.pipe = pipe; 1367 ret = fuse_dev_do_read(fud, in, &cs, len); 1368 if (ret < 0) 1369 goto out; 1370 1371 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) { 1372 ret = -EIO; 1373 goto out; 1374 } 1375 1376 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1377 /* 1378 * Need to be careful about this. Having buf->ops in module 1379 * code can Oops if the buffer persists after module unload. 1380 */ 1381 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1382 bufs[page_nr].flags = 0; 1383 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1384 if (unlikely(ret < 0)) 1385 break; 1386 } 1387 if (total) 1388 ret = total; 1389 out: 1390 for (; page_nr < cs.nr_segs; page_nr++) 1391 put_page(bufs[page_nr].page); 1392 1393 kfree(bufs); 1394 return ret; 1395 } 1396 1397 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1398 struct fuse_copy_state *cs) 1399 { 1400 struct fuse_notify_poll_wakeup_out outarg; 1401 int err = -EINVAL; 1402 1403 if (size != sizeof(outarg)) 1404 goto err; 1405 1406 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1407 if (err) 1408 goto err; 1409 1410 fuse_copy_finish(cs); 1411 return fuse_notify_poll_wakeup(fc, &outarg); 1412 1413 err: 1414 fuse_copy_finish(cs); 1415 return err; 1416 } 1417 1418 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1419 struct fuse_copy_state *cs) 1420 { 1421 struct fuse_notify_inval_inode_out outarg; 1422 int err = -EINVAL; 1423 1424 if (size != sizeof(outarg)) 1425 goto err; 1426 1427 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1428 if (err) 1429 goto err; 1430 fuse_copy_finish(cs); 1431 1432 down_read(&fc->killsb); 1433 err = -ENOENT; 1434 if (fc->sb) { 1435 err = fuse_reverse_inval_inode(fc->sb, outarg.ino, 1436 outarg.off, outarg.len); 1437 } 1438 up_read(&fc->killsb); 1439 return err; 1440 1441 err: 1442 fuse_copy_finish(cs); 1443 return err; 1444 } 1445 1446 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1447 struct fuse_copy_state *cs) 1448 { 1449 struct fuse_notify_inval_entry_out outarg; 1450 int err = -ENOMEM; 1451 char *buf; 1452 struct qstr name; 1453 1454 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1455 if (!buf) 1456 goto err; 1457 1458 err = -EINVAL; 1459 if (size < sizeof(outarg)) 1460 goto err; 1461 1462 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1463 if (err) 1464 goto err; 1465 1466 err = -ENAMETOOLONG; 1467 if (outarg.namelen > FUSE_NAME_MAX) 1468 goto err; 1469 1470 err = -EINVAL; 1471 if (size != sizeof(outarg) + outarg.namelen + 1) 1472 goto err; 1473 1474 name.name = buf; 1475 name.len = outarg.namelen; 1476 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1477 if (err) 1478 goto err; 1479 fuse_copy_finish(cs); 1480 buf[outarg.namelen] = 0; 1481 1482 down_read(&fc->killsb); 1483 err = -ENOENT; 1484 if (fc->sb) 1485 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name); 1486 up_read(&fc->killsb); 1487 kfree(buf); 1488 return err; 1489 1490 err: 1491 kfree(buf); 1492 fuse_copy_finish(cs); 1493 return err; 1494 } 1495 1496 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1497 struct fuse_copy_state *cs) 1498 { 1499 struct fuse_notify_delete_out outarg; 1500 int err = -ENOMEM; 1501 char *buf; 1502 struct qstr name; 1503 1504 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1505 if (!buf) 1506 goto err; 1507 1508 err = -EINVAL; 1509 if (size < sizeof(outarg)) 1510 goto err; 1511 1512 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1513 if (err) 1514 goto err; 1515 1516 err = -ENAMETOOLONG; 1517 if (outarg.namelen > FUSE_NAME_MAX) 1518 goto err; 1519 1520 err = -EINVAL; 1521 if (size != sizeof(outarg) + outarg.namelen + 1) 1522 goto err; 1523 1524 name.name = buf; 1525 name.len = outarg.namelen; 1526 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1527 if (err) 1528 goto err; 1529 fuse_copy_finish(cs); 1530 buf[outarg.namelen] = 0; 1531 1532 down_read(&fc->killsb); 1533 err = -ENOENT; 1534 if (fc->sb) 1535 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 1536 outarg.child, &name); 1537 up_read(&fc->killsb); 1538 kfree(buf); 1539 return err; 1540 1541 err: 1542 kfree(buf); 1543 fuse_copy_finish(cs); 1544 return err; 1545 } 1546 1547 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1548 struct fuse_copy_state *cs) 1549 { 1550 struct fuse_notify_store_out outarg; 1551 struct inode *inode; 1552 struct address_space *mapping; 1553 u64 nodeid; 1554 int err; 1555 pgoff_t index; 1556 unsigned int offset; 1557 unsigned int num; 1558 loff_t file_size; 1559 loff_t end; 1560 1561 err = -EINVAL; 1562 if (size < sizeof(outarg)) 1563 goto out_finish; 1564 1565 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1566 if (err) 1567 goto out_finish; 1568 1569 err = -EINVAL; 1570 if (size - sizeof(outarg) != outarg.size) 1571 goto out_finish; 1572 1573 nodeid = outarg.nodeid; 1574 1575 down_read(&fc->killsb); 1576 1577 err = -ENOENT; 1578 if (!fc->sb) 1579 goto out_up_killsb; 1580 1581 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1582 if (!inode) 1583 goto out_up_killsb; 1584 1585 mapping = inode->i_mapping; 1586 index = outarg.offset >> PAGE_SHIFT; 1587 offset = outarg.offset & ~PAGE_MASK; 1588 file_size = i_size_read(inode); 1589 end = outarg.offset + outarg.size; 1590 if (end > file_size) { 1591 file_size = end; 1592 fuse_write_update_size(inode, file_size); 1593 } 1594 1595 num = outarg.size; 1596 while (num) { 1597 struct page *page; 1598 unsigned int this_num; 1599 1600 err = -ENOMEM; 1601 page = find_or_create_page(mapping, index, 1602 mapping_gfp_mask(mapping)); 1603 if (!page) 1604 goto out_iput; 1605 1606 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1607 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1608 if (!err && offset == 0 && 1609 (this_num == PAGE_SIZE || file_size == end)) 1610 SetPageUptodate(page); 1611 unlock_page(page); 1612 put_page(page); 1613 1614 if (err) 1615 goto out_iput; 1616 1617 num -= this_num; 1618 offset = 0; 1619 index++; 1620 } 1621 1622 err = 0; 1623 1624 out_iput: 1625 iput(inode); 1626 out_up_killsb: 1627 up_read(&fc->killsb); 1628 out_finish: 1629 fuse_copy_finish(cs); 1630 return err; 1631 } 1632 1633 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req) 1634 { 1635 release_pages(req->pages, req->num_pages, false); 1636 } 1637 1638 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, 1639 struct fuse_notify_retrieve_out *outarg) 1640 { 1641 int err; 1642 struct address_space *mapping = inode->i_mapping; 1643 struct fuse_req *req; 1644 pgoff_t index; 1645 loff_t file_size; 1646 unsigned int num; 1647 unsigned int offset; 1648 size_t total_len = 0; 1649 int num_pages; 1650 1651 offset = outarg->offset & ~PAGE_MASK; 1652 file_size = i_size_read(inode); 1653 1654 num = outarg->size; 1655 if (outarg->offset > file_size) 1656 num = 0; 1657 else if (outarg->offset + num > file_size) 1658 num = file_size - outarg->offset; 1659 1660 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1661 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ); 1662 1663 req = fuse_get_req(fc, num_pages); 1664 if (IS_ERR(req)) 1665 return PTR_ERR(req); 1666 1667 req->in.h.opcode = FUSE_NOTIFY_REPLY; 1668 req->in.h.nodeid = outarg->nodeid; 1669 req->in.numargs = 2; 1670 req->in.argpages = 1; 1671 req->page_descs[0].offset = offset; 1672 req->end = fuse_retrieve_end; 1673 1674 index = outarg->offset >> PAGE_SHIFT; 1675 1676 while (num && req->num_pages < num_pages) { 1677 struct page *page; 1678 unsigned int this_num; 1679 1680 page = find_get_page(mapping, index); 1681 if (!page) 1682 break; 1683 1684 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1685 req->pages[req->num_pages] = page; 1686 req->page_descs[req->num_pages].length = this_num; 1687 req->num_pages++; 1688 1689 offset = 0; 1690 num -= this_num; 1691 total_len += this_num; 1692 index++; 1693 } 1694 req->misc.retrieve_in.offset = outarg->offset; 1695 req->misc.retrieve_in.size = total_len; 1696 req->in.args[0].size = sizeof(req->misc.retrieve_in); 1697 req->in.args[0].value = &req->misc.retrieve_in; 1698 req->in.args[1].size = total_len; 1699 1700 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique); 1701 if (err) 1702 fuse_retrieve_end(fc, req); 1703 1704 return err; 1705 } 1706 1707 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1708 struct fuse_copy_state *cs) 1709 { 1710 struct fuse_notify_retrieve_out outarg; 1711 struct inode *inode; 1712 int err; 1713 1714 err = -EINVAL; 1715 if (size != sizeof(outarg)) 1716 goto copy_finish; 1717 1718 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1719 if (err) 1720 goto copy_finish; 1721 1722 fuse_copy_finish(cs); 1723 1724 down_read(&fc->killsb); 1725 err = -ENOENT; 1726 if (fc->sb) { 1727 u64 nodeid = outarg.nodeid; 1728 1729 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1730 if (inode) { 1731 err = fuse_retrieve(fc, inode, &outarg); 1732 iput(inode); 1733 } 1734 } 1735 up_read(&fc->killsb); 1736 1737 return err; 1738 1739 copy_finish: 1740 fuse_copy_finish(cs); 1741 return err; 1742 } 1743 1744 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1745 unsigned int size, struct fuse_copy_state *cs) 1746 { 1747 /* Don't try to move pages (yet) */ 1748 cs->move_pages = 0; 1749 1750 switch (code) { 1751 case FUSE_NOTIFY_POLL: 1752 return fuse_notify_poll(fc, size, cs); 1753 1754 case FUSE_NOTIFY_INVAL_INODE: 1755 return fuse_notify_inval_inode(fc, size, cs); 1756 1757 case FUSE_NOTIFY_INVAL_ENTRY: 1758 return fuse_notify_inval_entry(fc, size, cs); 1759 1760 case FUSE_NOTIFY_STORE: 1761 return fuse_notify_store(fc, size, cs); 1762 1763 case FUSE_NOTIFY_RETRIEVE: 1764 return fuse_notify_retrieve(fc, size, cs); 1765 1766 case FUSE_NOTIFY_DELETE: 1767 return fuse_notify_delete(fc, size, cs); 1768 1769 default: 1770 fuse_copy_finish(cs); 1771 return -EINVAL; 1772 } 1773 } 1774 1775 /* Look up request on processing list by unique ID */ 1776 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1777 { 1778 struct fuse_req *req; 1779 1780 list_for_each_entry(req, &fpq->processing, list) { 1781 if (req->in.h.unique == unique || req->intr_unique == unique) 1782 return req; 1783 } 1784 return NULL; 1785 } 1786 1787 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, 1788 unsigned nbytes) 1789 { 1790 unsigned reqsize = sizeof(struct fuse_out_header); 1791 1792 if (out->h.error) 1793 return nbytes != reqsize ? -EINVAL : 0; 1794 1795 reqsize += len_args(out->numargs, out->args); 1796 1797 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) 1798 return -EINVAL; 1799 else if (reqsize > nbytes) { 1800 struct fuse_arg *lastarg = &out->args[out->numargs-1]; 1801 unsigned diffsize = reqsize - nbytes; 1802 if (diffsize > lastarg->size) 1803 return -EINVAL; 1804 lastarg->size -= diffsize; 1805 } 1806 return fuse_copy_args(cs, out->numargs, out->argpages, out->args, 1807 out->page_zeroing); 1808 } 1809 1810 /* 1811 * Write a single reply to a request. First the header is copied from 1812 * the write buffer. The request is then searched on the processing 1813 * list by the unique ID found in the header. If found, then remove 1814 * it from the list and copy the rest of the buffer to the request. 1815 * The request is finished by calling request_end() 1816 */ 1817 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1818 struct fuse_copy_state *cs, size_t nbytes) 1819 { 1820 int err; 1821 struct fuse_conn *fc = fud->fc; 1822 struct fuse_pqueue *fpq = &fud->pq; 1823 struct fuse_req *req; 1824 struct fuse_out_header oh; 1825 1826 if (task_active_pid_ns(current) != fc->pid_ns) 1827 return -EIO; 1828 1829 if (nbytes < sizeof(struct fuse_out_header)) 1830 return -EINVAL; 1831 1832 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1833 if (err) 1834 goto err_finish; 1835 1836 err = -EINVAL; 1837 if (oh.len != nbytes) 1838 goto err_finish; 1839 1840 /* 1841 * Zero oh.unique indicates unsolicited notification message 1842 * and error contains notification code. 1843 */ 1844 if (!oh.unique) { 1845 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1846 return err ? err : nbytes; 1847 } 1848 1849 err = -EINVAL; 1850 if (oh.error <= -1000 || oh.error > 0) 1851 goto err_finish; 1852 1853 spin_lock(&fpq->lock); 1854 err = -ENOENT; 1855 if (!fpq->connected) 1856 goto err_unlock_pq; 1857 1858 req = request_find(fpq, oh.unique); 1859 if (!req) 1860 goto err_unlock_pq; 1861 1862 /* Is it an interrupt reply? */ 1863 if (req->intr_unique == oh.unique) { 1864 spin_unlock(&fpq->lock); 1865 1866 err = -EINVAL; 1867 if (nbytes != sizeof(struct fuse_out_header)) 1868 goto err_finish; 1869 1870 if (oh.error == -ENOSYS) 1871 fc->no_interrupt = 1; 1872 else if (oh.error == -EAGAIN) 1873 queue_interrupt(&fc->iq, req); 1874 1875 fuse_copy_finish(cs); 1876 return nbytes; 1877 } 1878 1879 clear_bit(FR_SENT, &req->flags); 1880 list_move(&req->list, &fpq->io); 1881 req->out.h = oh; 1882 set_bit(FR_LOCKED, &req->flags); 1883 spin_unlock(&fpq->lock); 1884 cs->req = req; 1885 if (!req->out.page_replace) 1886 cs->move_pages = 0; 1887 1888 err = copy_out_args(cs, &req->out, nbytes); 1889 fuse_copy_finish(cs); 1890 1891 spin_lock(&fpq->lock); 1892 clear_bit(FR_LOCKED, &req->flags); 1893 if (!fpq->connected) 1894 err = -ENOENT; 1895 else if (err) 1896 req->out.h.error = -EIO; 1897 if (!test_bit(FR_PRIVATE, &req->flags)) 1898 list_del_init(&req->list); 1899 spin_unlock(&fpq->lock); 1900 1901 request_end(fc, req); 1902 1903 return err ? err : nbytes; 1904 1905 err_unlock_pq: 1906 spin_unlock(&fpq->lock); 1907 err_finish: 1908 fuse_copy_finish(cs); 1909 return err; 1910 } 1911 1912 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 1913 { 1914 struct fuse_copy_state cs; 1915 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 1916 1917 if (!fud) 1918 return -EPERM; 1919 1920 if (!iter_is_iovec(from)) 1921 return -EINVAL; 1922 1923 fuse_copy_init(&cs, 0, from); 1924 1925 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 1926 } 1927 1928 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1929 struct file *out, loff_t *ppos, 1930 size_t len, unsigned int flags) 1931 { 1932 unsigned nbuf; 1933 unsigned idx; 1934 struct pipe_buffer *bufs; 1935 struct fuse_copy_state cs; 1936 struct fuse_dev *fud; 1937 size_t rem; 1938 ssize_t ret; 1939 1940 fud = fuse_get_dev(out); 1941 if (!fud) 1942 return -EPERM; 1943 1944 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1945 if (!bufs) 1946 return -ENOMEM; 1947 1948 pipe_lock(pipe); 1949 nbuf = 0; 1950 rem = 0; 1951 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) 1952 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; 1953 1954 ret = -EINVAL; 1955 if (rem < len) { 1956 pipe_unlock(pipe); 1957 goto out; 1958 } 1959 1960 rem = len; 1961 while (rem) { 1962 struct pipe_buffer *ibuf; 1963 struct pipe_buffer *obuf; 1964 1965 BUG_ON(nbuf >= pipe->buffers); 1966 BUG_ON(!pipe->nrbufs); 1967 ibuf = &pipe->bufs[pipe->curbuf]; 1968 obuf = &bufs[nbuf]; 1969 1970 if (rem >= ibuf->len) { 1971 *obuf = *ibuf; 1972 ibuf->ops = NULL; 1973 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 1974 pipe->nrbufs--; 1975 } else { 1976 pipe_buf_get(pipe, ibuf); 1977 *obuf = *ibuf; 1978 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1979 obuf->len = rem; 1980 ibuf->offset += obuf->len; 1981 ibuf->len -= obuf->len; 1982 } 1983 nbuf++; 1984 rem -= obuf->len; 1985 } 1986 pipe_unlock(pipe); 1987 1988 fuse_copy_init(&cs, 0, NULL); 1989 cs.pipebufs = bufs; 1990 cs.nr_segs = nbuf; 1991 cs.pipe = pipe; 1992 1993 if (flags & SPLICE_F_MOVE) 1994 cs.move_pages = 1; 1995 1996 ret = fuse_dev_do_write(fud, &cs, len); 1997 1998 for (idx = 0; idx < nbuf; idx++) 1999 pipe_buf_release(pipe, &bufs[idx]); 2000 2001 out: 2002 kfree(bufs); 2003 return ret; 2004 } 2005 2006 static unsigned fuse_dev_poll(struct file *file, poll_table *wait) 2007 { 2008 unsigned mask = POLLOUT | POLLWRNORM; 2009 struct fuse_iqueue *fiq; 2010 struct fuse_dev *fud = fuse_get_dev(file); 2011 2012 if (!fud) 2013 return POLLERR; 2014 2015 fiq = &fud->fc->iq; 2016 poll_wait(file, &fiq->waitq, wait); 2017 2018 spin_lock(&fiq->waitq.lock); 2019 if (!fiq->connected) 2020 mask = POLLERR; 2021 else if (request_pending(fiq)) 2022 mask |= POLLIN | POLLRDNORM; 2023 spin_unlock(&fiq->waitq.lock); 2024 2025 return mask; 2026 } 2027 2028 /* 2029 * Abort all requests on the given list (pending or processing) 2030 * 2031 * This function releases and reacquires fc->lock 2032 */ 2033 static void end_requests(struct fuse_conn *fc, struct list_head *head) 2034 { 2035 while (!list_empty(head)) { 2036 struct fuse_req *req; 2037 req = list_entry(head->next, struct fuse_req, list); 2038 req->out.h.error = -ECONNABORTED; 2039 clear_bit(FR_SENT, &req->flags); 2040 list_del_init(&req->list); 2041 request_end(fc, req); 2042 } 2043 } 2044 2045 static void end_polls(struct fuse_conn *fc) 2046 { 2047 struct rb_node *p; 2048 2049 p = rb_first(&fc->polled_files); 2050 2051 while (p) { 2052 struct fuse_file *ff; 2053 ff = rb_entry(p, struct fuse_file, polled_node); 2054 wake_up_interruptible_all(&ff->poll_wait); 2055 2056 p = rb_next(p); 2057 } 2058 } 2059 2060 /* 2061 * Abort all requests. 2062 * 2063 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2064 * filesystem. 2065 * 2066 * The same effect is usually achievable through killing the filesystem daemon 2067 * and all users of the filesystem. The exception is the combination of an 2068 * asynchronous request and the tricky deadlock (see 2069 * Documentation/filesystems/fuse.txt). 2070 * 2071 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2072 * requests, they should be finished off immediately. Locked requests will be 2073 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2074 * requests. It is possible that some request will finish before we can. This 2075 * is OK, the request will in that case be removed from the list before we touch 2076 * it. 2077 */ 2078 void fuse_abort_conn(struct fuse_conn *fc) 2079 { 2080 struct fuse_iqueue *fiq = &fc->iq; 2081 2082 spin_lock(&fc->lock); 2083 if (fc->connected) { 2084 struct fuse_dev *fud; 2085 struct fuse_req *req, *next; 2086 LIST_HEAD(to_end1); 2087 LIST_HEAD(to_end2); 2088 2089 fc->connected = 0; 2090 fc->blocked = 0; 2091 fuse_set_initialized(fc); 2092 list_for_each_entry(fud, &fc->devices, entry) { 2093 struct fuse_pqueue *fpq = &fud->pq; 2094 2095 spin_lock(&fpq->lock); 2096 fpq->connected = 0; 2097 list_for_each_entry_safe(req, next, &fpq->io, list) { 2098 req->out.h.error = -ECONNABORTED; 2099 spin_lock(&req->waitq.lock); 2100 set_bit(FR_ABORTED, &req->flags); 2101 if (!test_bit(FR_LOCKED, &req->flags)) { 2102 set_bit(FR_PRIVATE, &req->flags); 2103 list_move(&req->list, &to_end1); 2104 } 2105 spin_unlock(&req->waitq.lock); 2106 } 2107 list_splice_init(&fpq->processing, &to_end2); 2108 spin_unlock(&fpq->lock); 2109 } 2110 fc->max_background = UINT_MAX; 2111 flush_bg_queue(fc); 2112 2113 spin_lock(&fiq->waitq.lock); 2114 fiq->connected = 0; 2115 list_splice_init(&fiq->pending, &to_end2); 2116 list_for_each_entry(req, &to_end2, list) 2117 clear_bit(FR_PENDING, &req->flags); 2118 while (forget_pending(fiq)) 2119 kfree(dequeue_forget(fiq, 1, NULL)); 2120 wake_up_all_locked(&fiq->waitq); 2121 spin_unlock(&fiq->waitq.lock); 2122 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2123 end_polls(fc); 2124 wake_up_all(&fc->blocked_waitq); 2125 spin_unlock(&fc->lock); 2126 2127 while (!list_empty(&to_end1)) { 2128 req = list_first_entry(&to_end1, struct fuse_req, list); 2129 __fuse_get_request(req); 2130 list_del_init(&req->list); 2131 request_end(fc, req); 2132 } 2133 end_requests(fc, &to_end2); 2134 } else { 2135 spin_unlock(&fc->lock); 2136 } 2137 } 2138 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2139 2140 int fuse_dev_release(struct inode *inode, struct file *file) 2141 { 2142 struct fuse_dev *fud = fuse_get_dev(file); 2143 2144 if (fud) { 2145 struct fuse_conn *fc = fud->fc; 2146 struct fuse_pqueue *fpq = &fud->pq; 2147 2148 WARN_ON(!list_empty(&fpq->io)); 2149 end_requests(fc, &fpq->processing); 2150 /* Are we the last open device? */ 2151 if (atomic_dec_and_test(&fc->dev_count)) { 2152 WARN_ON(fc->iq.fasync != NULL); 2153 fuse_abort_conn(fc); 2154 } 2155 fuse_dev_free(fud); 2156 } 2157 return 0; 2158 } 2159 EXPORT_SYMBOL_GPL(fuse_dev_release); 2160 2161 static int fuse_dev_fasync(int fd, struct file *file, int on) 2162 { 2163 struct fuse_dev *fud = fuse_get_dev(file); 2164 2165 if (!fud) 2166 return -EPERM; 2167 2168 /* No locking - fasync_helper does its own locking */ 2169 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2170 } 2171 2172 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2173 { 2174 struct fuse_dev *fud; 2175 2176 if (new->private_data) 2177 return -EINVAL; 2178 2179 fud = fuse_dev_alloc(fc); 2180 if (!fud) 2181 return -ENOMEM; 2182 2183 new->private_data = fud; 2184 atomic_inc(&fc->dev_count); 2185 2186 return 0; 2187 } 2188 2189 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2190 unsigned long arg) 2191 { 2192 int err = -ENOTTY; 2193 2194 if (cmd == FUSE_DEV_IOC_CLONE) { 2195 int oldfd; 2196 2197 err = -EFAULT; 2198 if (!get_user(oldfd, (__u32 __user *) arg)) { 2199 struct file *old = fget(oldfd); 2200 2201 err = -EINVAL; 2202 if (old) { 2203 struct fuse_dev *fud = NULL; 2204 2205 /* 2206 * Check against file->f_op because CUSE 2207 * uses the same ioctl handler. 2208 */ 2209 if (old->f_op == file->f_op && 2210 old->f_cred->user_ns == file->f_cred->user_ns) 2211 fud = fuse_get_dev(old); 2212 2213 if (fud) { 2214 mutex_lock(&fuse_mutex); 2215 err = fuse_device_clone(fud->fc, file); 2216 mutex_unlock(&fuse_mutex); 2217 } 2218 fput(old); 2219 } 2220 } 2221 } 2222 return err; 2223 } 2224 2225 const struct file_operations fuse_dev_operations = { 2226 .owner = THIS_MODULE, 2227 .open = fuse_dev_open, 2228 .llseek = no_llseek, 2229 .read_iter = fuse_dev_read, 2230 .splice_read = fuse_dev_splice_read, 2231 .write_iter = fuse_dev_write, 2232 .splice_write = fuse_dev_splice_write, 2233 .poll = fuse_dev_poll, 2234 .release = fuse_dev_release, 2235 .fasync = fuse_dev_fasync, 2236 .unlocked_ioctl = fuse_dev_ioctl, 2237 .compat_ioctl = fuse_dev_ioctl, 2238 }; 2239 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2240 2241 static struct miscdevice fuse_miscdevice = { 2242 .minor = FUSE_MINOR, 2243 .name = "fuse", 2244 .fops = &fuse_dev_operations, 2245 }; 2246 2247 int __init fuse_dev_init(void) 2248 { 2249 int err = -ENOMEM; 2250 fuse_req_cachep = kmem_cache_create("fuse_request", 2251 sizeof(struct fuse_req), 2252 0, 0, NULL); 2253 if (!fuse_req_cachep) 2254 goto out; 2255 2256 err = misc_register(&fuse_miscdevice); 2257 if (err) 2258 goto out_cache_clean; 2259 2260 return 0; 2261 2262 out_cache_clean: 2263 kmem_cache_destroy(fuse_req_cachep); 2264 out: 2265 return err; 2266 } 2267 2268 void fuse_dev_cleanup(void) 2269 { 2270 misc_deregister(&fuse_miscdevice); 2271 kmem_cache_destroy(fuse_req_cachep); 2272 } 2273