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