1 /* 2 FUSE: Filesystem in Userspace 3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> 4 5 This program can be distributed under the terms of the GNU GPL. 6 See the file COPYING. 7 */ 8 9 #include "fuse_i.h" 10 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/poll.h> 14 #include <linux/sched/signal.h> 15 #include <linux/uio.h> 16 #include <linux/miscdevice.h> 17 #include <linux/pagemap.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/pipe_fs_i.h> 21 #include <linux/swap.h> 22 #include <linux/splice.h> 23 #include <linux/sched.h> 24 25 MODULE_ALIAS_MISCDEV(FUSE_MINOR); 26 MODULE_ALIAS("devname:fuse"); 27 28 /* Ordinary requests have even IDs, while interrupts IDs are odd */ 29 #define FUSE_INT_REQ_BIT (1ULL << 0) 30 #define FUSE_REQ_ID_STEP (1ULL << 1) 31 32 static struct kmem_cache *fuse_req_cachep; 33 34 static struct fuse_dev *fuse_get_dev(struct file *file) 35 { 36 /* 37 * Lockless access is OK, because file->private data is set 38 * once during mount and is valid until the file is released. 39 */ 40 return READ_ONCE(file->private_data); 41 } 42 43 static void fuse_request_init(struct fuse_req *req, struct page **pages, 44 struct fuse_page_desc *page_descs, 45 unsigned npages) 46 { 47 INIT_LIST_HEAD(&req->list); 48 INIT_LIST_HEAD(&req->intr_entry); 49 init_waitqueue_head(&req->waitq); 50 refcount_set(&req->count, 1); 51 req->pages = pages; 52 req->page_descs = page_descs; 53 req->max_pages = npages; 54 __set_bit(FR_PENDING, &req->flags); 55 } 56 57 static struct page **fuse_req_pages_alloc(unsigned int npages, gfp_t flags, 58 struct fuse_page_desc **desc) 59 { 60 struct page **pages; 61 62 pages = kzalloc(npages * (sizeof(struct page *) + 63 sizeof(struct fuse_page_desc)), flags); 64 *desc = (void *) pages + npages * sizeof(struct page *); 65 66 return pages; 67 } 68 69 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags) 70 { 71 struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags); 72 if (req) { 73 struct page **pages = NULL; 74 struct fuse_page_desc *page_descs = NULL; 75 76 WARN_ON(npages > FUSE_MAX_MAX_PAGES); 77 if (npages > FUSE_REQ_INLINE_PAGES) { 78 pages = fuse_req_pages_alloc(npages, flags, 79 &page_descs); 80 if (!pages) { 81 kmem_cache_free(fuse_req_cachep, req); 82 return NULL; 83 } 84 } else if (npages) { 85 pages = req->inline_pages; 86 page_descs = req->inline_page_descs; 87 } 88 89 fuse_request_init(req, pages, page_descs, npages); 90 } 91 return req; 92 } 93 94 struct fuse_req *fuse_request_alloc(unsigned npages) 95 { 96 return __fuse_request_alloc(npages, GFP_KERNEL); 97 } 98 EXPORT_SYMBOL_GPL(fuse_request_alloc); 99 100 struct fuse_req *fuse_request_alloc_nofs(unsigned npages) 101 { 102 return __fuse_request_alloc(npages, GFP_NOFS); 103 } 104 105 static void fuse_req_pages_free(struct fuse_req *req) 106 { 107 if (req->pages != req->inline_pages) 108 kfree(req->pages); 109 } 110 111 bool fuse_req_realloc_pages(struct fuse_conn *fc, struct fuse_req *req, 112 gfp_t flags) 113 { 114 struct page **pages; 115 struct fuse_page_desc *page_descs; 116 unsigned int npages = min_t(unsigned int, 117 max_t(unsigned int, req->max_pages * 2, 118 FUSE_DEFAULT_MAX_PAGES_PER_REQ), 119 fc->max_pages); 120 WARN_ON(npages <= req->max_pages); 121 122 pages = fuse_req_pages_alloc(npages, flags, &page_descs); 123 if (!pages) 124 return false; 125 126 memcpy(pages, req->pages, sizeof(struct page *) * req->max_pages); 127 memcpy(page_descs, req->page_descs, 128 sizeof(struct fuse_page_desc) * req->max_pages); 129 fuse_req_pages_free(req); 130 req->pages = pages; 131 req->page_descs = page_descs; 132 req->max_pages = npages; 133 134 return true; 135 } 136 137 void fuse_request_free(struct fuse_req *req) 138 { 139 fuse_req_pages_free(req); 140 kmem_cache_free(fuse_req_cachep, req); 141 } 142 143 void __fuse_get_request(struct fuse_req *req) 144 { 145 refcount_inc(&req->count); 146 } 147 148 /* Must be called with > 1 refcount */ 149 static void __fuse_put_request(struct fuse_req *req) 150 { 151 refcount_dec(&req->count); 152 } 153 154 void fuse_set_initialized(struct fuse_conn *fc) 155 { 156 /* Make sure stores before this are seen on another CPU */ 157 smp_wmb(); 158 fc->initialized = 1; 159 } 160 161 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background) 162 { 163 return !fc->initialized || (for_background && fc->blocked); 164 } 165 166 static void fuse_drop_waiting(struct fuse_conn *fc) 167 { 168 /* 169 * lockess check of fc->connected is okay, because atomic_dec_and_test() 170 * provides a memory barrier mached with the one in fuse_wait_aborted() 171 * to ensure no wake-up is missed. 172 */ 173 if (atomic_dec_and_test(&fc->num_waiting) && 174 !READ_ONCE(fc->connected)) { 175 /* wake up aborters */ 176 wake_up_all(&fc->blocked_waitq); 177 } 178 } 179 180 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages, 181 bool for_background) 182 { 183 struct fuse_req *req; 184 int err; 185 atomic_inc(&fc->num_waiting); 186 187 if (fuse_block_alloc(fc, for_background)) { 188 err = -EINTR; 189 if (wait_event_killable_exclusive(fc->blocked_waitq, 190 !fuse_block_alloc(fc, for_background))) 191 goto out; 192 } 193 /* Matches smp_wmb() in fuse_set_initialized() */ 194 smp_rmb(); 195 196 err = -ENOTCONN; 197 if (!fc->connected) 198 goto out; 199 200 err = -ECONNREFUSED; 201 if (fc->conn_error) 202 goto out; 203 204 req = fuse_request_alloc(npages); 205 err = -ENOMEM; 206 if (!req) { 207 if (for_background) 208 wake_up(&fc->blocked_waitq); 209 goto out; 210 } 211 212 req->in.h.uid = from_kuid(fc->user_ns, current_fsuid()); 213 req->in.h.gid = from_kgid(fc->user_ns, current_fsgid()); 214 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 215 216 __set_bit(FR_WAITING, &req->flags); 217 if (for_background) 218 __set_bit(FR_BACKGROUND, &req->flags); 219 220 if (unlikely(req->in.h.uid == ((uid_t)-1) || 221 req->in.h.gid == ((gid_t)-1))) { 222 fuse_put_request(fc, req); 223 return ERR_PTR(-EOVERFLOW); 224 } 225 return req; 226 227 out: 228 fuse_drop_waiting(fc); 229 return ERR_PTR(err); 230 } 231 232 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages) 233 { 234 return __fuse_get_req(fc, npages, false); 235 } 236 EXPORT_SYMBOL_GPL(fuse_get_req); 237 238 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc, 239 unsigned npages) 240 { 241 return __fuse_get_req(fc, npages, true); 242 } 243 EXPORT_SYMBOL_GPL(fuse_get_req_for_background); 244 245 /* 246 * Return request in fuse_file->reserved_req. However that may 247 * currently be in use. If that is the case, wait for it to become 248 * available. 249 */ 250 static struct fuse_req *get_reserved_req(struct fuse_conn *fc, 251 struct file *file) 252 { 253 struct fuse_req *req = NULL; 254 struct fuse_inode *fi = get_fuse_inode(file_inode(file)); 255 struct fuse_file *ff = file->private_data; 256 257 do { 258 wait_event(fc->reserved_req_waitq, ff->reserved_req); 259 spin_lock(&fi->lock); 260 if (ff->reserved_req) { 261 req = ff->reserved_req; 262 ff->reserved_req = NULL; 263 req->stolen_file = get_file(file); 264 } 265 spin_unlock(&fi->lock); 266 } while (!req); 267 268 return req; 269 } 270 271 /* 272 * Put stolen request back into fuse_file->reserved_req 273 */ 274 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req) 275 { 276 struct file *file = req->stolen_file; 277 struct fuse_inode *fi = get_fuse_inode(file_inode(file)); 278 struct fuse_file *ff = file->private_data; 279 280 WARN_ON(req->max_pages); 281 spin_lock(&fi->lock); 282 memset(req, 0, sizeof(*req)); 283 fuse_request_init(req, NULL, NULL, 0); 284 BUG_ON(ff->reserved_req); 285 ff->reserved_req = req; 286 wake_up_all(&fc->reserved_req_waitq); 287 spin_unlock(&fi->lock); 288 fput(file); 289 } 290 291 /* 292 * Gets a requests for a file operation, always succeeds 293 * 294 * This is used for sending the FLUSH request, which must get to 295 * userspace, due to POSIX locks which may need to be unlocked. 296 * 297 * If allocation fails due to OOM, use the reserved request in 298 * fuse_file. 299 * 300 * This is very unlikely to deadlock accidentally, since the 301 * filesystem should not have it's own file open. If deadlock is 302 * intentional, it can still be broken by "aborting" the filesystem. 303 */ 304 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc, 305 struct file *file) 306 { 307 struct fuse_req *req; 308 309 atomic_inc(&fc->num_waiting); 310 wait_event(fc->blocked_waitq, fc->initialized); 311 /* Matches smp_wmb() in fuse_set_initialized() */ 312 smp_rmb(); 313 req = fuse_request_alloc(0); 314 if (!req) 315 req = get_reserved_req(fc, file); 316 317 req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid()); 318 req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid()); 319 req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns); 320 321 __set_bit(FR_WAITING, &req->flags); 322 __clear_bit(FR_BACKGROUND, &req->flags); 323 return req; 324 } 325 326 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) 327 { 328 if (refcount_dec_and_test(&req->count)) { 329 if (test_bit(FR_BACKGROUND, &req->flags)) { 330 /* 331 * We get here in the unlikely case that a background 332 * request was allocated but not sent 333 */ 334 spin_lock(&fc->bg_lock); 335 if (!fc->blocked) 336 wake_up(&fc->blocked_waitq); 337 spin_unlock(&fc->bg_lock); 338 } 339 340 if (test_bit(FR_WAITING, &req->flags)) { 341 __clear_bit(FR_WAITING, &req->flags); 342 fuse_drop_waiting(fc); 343 } 344 345 if (req->stolen_file) 346 put_reserved_req(fc, req); 347 else 348 fuse_request_free(req); 349 } 350 } 351 EXPORT_SYMBOL_GPL(fuse_put_request); 352 353 static unsigned len_args(unsigned numargs, struct fuse_arg *args) 354 { 355 unsigned nbytes = 0; 356 unsigned i; 357 358 for (i = 0; i < numargs; i++) 359 nbytes += args[i].size; 360 361 return nbytes; 362 } 363 364 static u64 fuse_get_unique(struct fuse_iqueue *fiq) 365 { 366 fiq->reqctr += FUSE_REQ_ID_STEP; 367 return fiq->reqctr; 368 } 369 370 static unsigned int fuse_req_hash(u64 unique) 371 { 372 return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS); 373 } 374 375 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req) 376 { 377 req->in.h.len = sizeof(struct fuse_in_header) + 378 len_args(req->in.numargs, (struct fuse_arg *) req->in.args); 379 list_add_tail(&req->list, &fiq->pending); 380 wake_up_locked(&fiq->waitq); 381 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 382 } 383 384 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget, 385 u64 nodeid, u64 nlookup) 386 { 387 struct fuse_iqueue *fiq = &fc->iq; 388 389 forget->forget_one.nodeid = nodeid; 390 forget->forget_one.nlookup = nlookup; 391 392 spin_lock(&fiq->waitq.lock); 393 if (fiq->connected) { 394 fiq->forget_list_tail->next = forget; 395 fiq->forget_list_tail = forget; 396 wake_up_locked(&fiq->waitq); 397 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 398 } else { 399 kfree(forget); 400 } 401 spin_unlock(&fiq->waitq.lock); 402 } 403 404 static void flush_bg_queue(struct fuse_conn *fc) 405 { 406 struct fuse_iqueue *fiq = &fc->iq; 407 408 while (fc->active_background < fc->max_background && 409 !list_empty(&fc->bg_queue)) { 410 struct fuse_req *req; 411 412 req = list_first_entry(&fc->bg_queue, struct fuse_req, list); 413 list_del(&req->list); 414 fc->active_background++; 415 spin_lock(&fiq->waitq.lock); 416 req->in.h.unique = fuse_get_unique(fiq); 417 queue_request(fiq, req); 418 spin_unlock(&fiq->waitq.lock); 419 } 420 } 421 422 /* 423 * This function is called when a request is finished. Either a reply 424 * has arrived or it was aborted (and not yet sent) or some error 425 * occurred during communication with userspace, or the device file 426 * was closed. The requester thread is woken up (if still waiting), 427 * the 'end' callback is called if given, else the reference to the 428 * request is released 429 */ 430 static void request_end(struct fuse_conn *fc, struct fuse_req *req) 431 { 432 struct fuse_iqueue *fiq = &fc->iq; 433 434 if (test_and_set_bit(FR_FINISHED, &req->flags)) 435 goto put_request; 436 /* 437 * test_and_set_bit() implies smp_mb() between bit 438 * changing and below intr_entry check. Pairs with 439 * smp_mb() from queue_interrupt(). 440 */ 441 if (!list_empty(&req->intr_entry)) { 442 spin_lock(&fiq->waitq.lock); 443 list_del_init(&req->intr_entry); 444 spin_unlock(&fiq->waitq.lock); 445 } 446 WARN_ON(test_bit(FR_PENDING, &req->flags)); 447 WARN_ON(test_bit(FR_SENT, &req->flags)); 448 if (test_bit(FR_BACKGROUND, &req->flags)) { 449 spin_lock(&fc->bg_lock); 450 clear_bit(FR_BACKGROUND, &req->flags); 451 if (fc->num_background == fc->max_background) { 452 fc->blocked = 0; 453 wake_up(&fc->blocked_waitq); 454 } else if (!fc->blocked) { 455 /* 456 * Wake up next waiter, if any. It's okay to use 457 * waitqueue_active(), as we've already synced up 458 * fc->blocked with waiters with the wake_up() call 459 * above. 460 */ 461 if (waitqueue_active(&fc->blocked_waitq)) 462 wake_up(&fc->blocked_waitq); 463 } 464 465 if (fc->num_background == fc->congestion_threshold && fc->sb) { 466 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 467 clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 468 } 469 fc->num_background--; 470 fc->active_background--; 471 flush_bg_queue(fc); 472 spin_unlock(&fc->bg_lock); 473 } else { 474 /* Wake up waiter sleeping in request_wait_answer() */ 475 wake_up(&req->waitq); 476 } 477 478 if (req->end) 479 req->end(fc, req); 480 put_request: 481 fuse_put_request(fc, req); 482 } 483 484 static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) 485 { 486 spin_lock(&fiq->waitq.lock); 487 /* Check for we've sent request to interrupt this req */ 488 if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) { 489 spin_unlock(&fiq->waitq.lock); 490 return -EINVAL; 491 } 492 493 if (list_empty(&req->intr_entry)) { 494 list_add_tail(&req->intr_entry, &fiq->interrupts); 495 /* 496 * Pairs with smp_mb() implied by test_and_set_bit() 497 * from request_end(). 498 */ 499 smp_mb(); 500 if (test_bit(FR_FINISHED, &req->flags)) { 501 list_del_init(&req->intr_entry); 502 spin_unlock(&fiq->waitq.lock); 503 return 0; 504 } 505 wake_up_locked(&fiq->waitq); 506 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 507 } 508 spin_unlock(&fiq->waitq.lock); 509 return 0; 510 } 511 512 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) 513 { 514 struct fuse_iqueue *fiq = &fc->iq; 515 int err; 516 517 if (!fc->no_interrupt) { 518 /* Any signal may interrupt this */ 519 err = wait_event_interruptible(req->waitq, 520 test_bit(FR_FINISHED, &req->flags)); 521 if (!err) 522 return; 523 524 set_bit(FR_INTERRUPTED, &req->flags); 525 /* matches barrier in fuse_dev_do_read() */ 526 smp_mb__after_atomic(); 527 if (test_bit(FR_SENT, &req->flags)) 528 queue_interrupt(fiq, req); 529 } 530 531 if (!test_bit(FR_FORCE, &req->flags)) { 532 /* Only fatal signals may interrupt this */ 533 err = wait_event_killable(req->waitq, 534 test_bit(FR_FINISHED, &req->flags)); 535 if (!err) 536 return; 537 538 spin_lock(&fiq->waitq.lock); 539 /* Request is not yet in userspace, bail out */ 540 if (test_bit(FR_PENDING, &req->flags)) { 541 list_del(&req->list); 542 spin_unlock(&fiq->waitq.lock); 543 __fuse_put_request(req); 544 req->out.h.error = -EINTR; 545 return; 546 } 547 spin_unlock(&fiq->waitq.lock); 548 } 549 550 /* 551 * Either request is already in userspace, or it was forced. 552 * Wait it out. 553 */ 554 wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags)); 555 } 556 557 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 558 { 559 struct fuse_iqueue *fiq = &fc->iq; 560 561 BUG_ON(test_bit(FR_BACKGROUND, &req->flags)); 562 spin_lock(&fiq->waitq.lock); 563 if (!fiq->connected) { 564 spin_unlock(&fiq->waitq.lock); 565 req->out.h.error = -ENOTCONN; 566 } else { 567 req->in.h.unique = fuse_get_unique(fiq); 568 queue_request(fiq, req); 569 /* acquire extra reference, since request is still needed 570 after request_end() */ 571 __fuse_get_request(req); 572 spin_unlock(&fiq->waitq.lock); 573 574 request_wait_answer(fc, req); 575 /* Pairs with smp_wmb() in request_end() */ 576 smp_rmb(); 577 } 578 } 579 580 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req) 581 { 582 __set_bit(FR_ISREPLY, &req->flags); 583 if (!test_bit(FR_WAITING, &req->flags)) { 584 __set_bit(FR_WAITING, &req->flags); 585 atomic_inc(&fc->num_waiting); 586 } 587 __fuse_request_send(fc, req); 588 } 589 EXPORT_SYMBOL_GPL(fuse_request_send); 590 591 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args) 592 { 593 if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS) 594 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE; 595 596 if (fc->minor < 9) { 597 switch (args->in.h.opcode) { 598 case FUSE_LOOKUP: 599 case FUSE_CREATE: 600 case FUSE_MKNOD: 601 case FUSE_MKDIR: 602 case FUSE_SYMLINK: 603 case FUSE_LINK: 604 args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE; 605 break; 606 case FUSE_GETATTR: 607 case FUSE_SETATTR: 608 args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE; 609 break; 610 } 611 } 612 if (fc->minor < 12) { 613 switch (args->in.h.opcode) { 614 case FUSE_CREATE: 615 args->in.args[0].size = sizeof(struct fuse_open_in); 616 break; 617 case FUSE_MKNOD: 618 args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE; 619 break; 620 } 621 } 622 } 623 624 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args) 625 { 626 struct fuse_req *req; 627 ssize_t ret; 628 629 req = fuse_get_req(fc, 0); 630 if (IS_ERR(req)) 631 return PTR_ERR(req); 632 633 /* Needs to be done after fuse_get_req() so that fc->minor is valid */ 634 fuse_adjust_compat(fc, args); 635 636 req->in.h.opcode = args->in.h.opcode; 637 req->in.h.nodeid = args->in.h.nodeid; 638 req->in.numargs = args->in.numargs; 639 memcpy(req->in.args, args->in.args, 640 args->in.numargs * sizeof(struct fuse_in_arg)); 641 req->out.argvar = args->out.argvar; 642 req->out.numargs = args->out.numargs; 643 memcpy(req->out.args, args->out.args, 644 args->out.numargs * sizeof(struct fuse_arg)); 645 fuse_request_send(fc, req); 646 ret = req->out.h.error; 647 if (!ret && args->out.argvar) { 648 BUG_ON(args->out.numargs != 1); 649 ret = req->out.args[0].size; 650 } 651 fuse_put_request(fc, req); 652 653 return ret; 654 } 655 656 bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req) 657 { 658 bool queued = false; 659 660 WARN_ON(!test_bit(FR_BACKGROUND, &req->flags)); 661 if (!test_bit(FR_WAITING, &req->flags)) { 662 __set_bit(FR_WAITING, &req->flags); 663 atomic_inc(&fc->num_waiting); 664 } 665 __set_bit(FR_ISREPLY, &req->flags); 666 spin_lock(&fc->bg_lock); 667 if (likely(fc->connected)) { 668 fc->num_background++; 669 if (fc->num_background == fc->max_background) 670 fc->blocked = 1; 671 if (fc->num_background == fc->congestion_threshold && fc->sb) { 672 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC); 673 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC); 674 } 675 list_add_tail(&req->list, &fc->bg_queue); 676 flush_bg_queue(fc); 677 queued = true; 678 } 679 spin_unlock(&fc->bg_lock); 680 681 return queued; 682 } 683 684 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) 685 { 686 WARN_ON(!req->end); 687 if (!fuse_request_queue_background(fc, req)) { 688 req->out.h.error = -ENOTCONN; 689 req->end(fc, req); 690 fuse_put_request(fc, req); 691 } 692 } 693 EXPORT_SYMBOL_GPL(fuse_request_send_background); 694 695 static int fuse_request_send_notify_reply(struct fuse_conn *fc, 696 struct fuse_req *req, u64 unique) 697 { 698 int err = -ENODEV; 699 struct fuse_iqueue *fiq = &fc->iq; 700 701 __clear_bit(FR_ISREPLY, &req->flags); 702 req->in.h.unique = unique; 703 spin_lock(&fiq->waitq.lock); 704 if (fiq->connected) { 705 queue_request(fiq, req); 706 err = 0; 707 } 708 spin_unlock(&fiq->waitq.lock); 709 710 return err; 711 } 712 713 void fuse_force_forget(struct file *file, u64 nodeid) 714 { 715 struct inode *inode = file_inode(file); 716 struct fuse_conn *fc = get_fuse_conn(inode); 717 struct fuse_req *req; 718 struct fuse_forget_in inarg; 719 720 memset(&inarg, 0, sizeof(inarg)); 721 inarg.nlookup = 1; 722 req = fuse_get_req_nofail_nopages(fc, file); 723 req->in.h.opcode = FUSE_FORGET; 724 req->in.h.nodeid = nodeid; 725 req->in.numargs = 1; 726 req->in.args[0].size = sizeof(inarg); 727 req->in.args[0].value = &inarg; 728 __clear_bit(FR_ISREPLY, &req->flags); 729 __fuse_request_send(fc, req); 730 /* ignore errors */ 731 fuse_put_request(fc, req); 732 } 733 734 /* 735 * Lock the request. Up to the next unlock_request() there mustn't be 736 * anything that could cause a page-fault. If the request was already 737 * aborted bail out. 738 */ 739 static int lock_request(struct fuse_req *req) 740 { 741 int err = 0; 742 if (req) { 743 spin_lock(&req->waitq.lock); 744 if (test_bit(FR_ABORTED, &req->flags)) 745 err = -ENOENT; 746 else 747 set_bit(FR_LOCKED, &req->flags); 748 spin_unlock(&req->waitq.lock); 749 } 750 return err; 751 } 752 753 /* 754 * Unlock request. If it was aborted while locked, caller is responsible 755 * for unlocking and ending the request. 756 */ 757 static int unlock_request(struct fuse_req *req) 758 { 759 int err = 0; 760 if (req) { 761 spin_lock(&req->waitq.lock); 762 if (test_bit(FR_ABORTED, &req->flags)) 763 err = -ENOENT; 764 else 765 clear_bit(FR_LOCKED, &req->flags); 766 spin_unlock(&req->waitq.lock); 767 } 768 return err; 769 } 770 771 struct fuse_copy_state { 772 int write; 773 struct fuse_req *req; 774 struct iov_iter *iter; 775 struct pipe_buffer *pipebufs; 776 struct pipe_buffer *currbuf; 777 struct pipe_inode_info *pipe; 778 unsigned long nr_segs; 779 struct page *pg; 780 unsigned len; 781 unsigned offset; 782 unsigned move_pages:1; 783 }; 784 785 static void fuse_copy_init(struct fuse_copy_state *cs, int write, 786 struct iov_iter *iter) 787 { 788 memset(cs, 0, sizeof(*cs)); 789 cs->write = write; 790 cs->iter = iter; 791 } 792 793 /* Unmap and put previous page of userspace buffer */ 794 static void fuse_copy_finish(struct fuse_copy_state *cs) 795 { 796 if (cs->currbuf) { 797 struct pipe_buffer *buf = cs->currbuf; 798 799 if (cs->write) 800 buf->len = PAGE_SIZE - cs->len; 801 cs->currbuf = NULL; 802 } else if (cs->pg) { 803 if (cs->write) { 804 flush_dcache_page(cs->pg); 805 set_page_dirty_lock(cs->pg); 806 } 807 put_page(cs->pg); 808 } 809 cs->pg = NULL; 810 } 811 812 /* 813 * Get another pagefull of userspace buffer, and map it to kernel 814 * address space, and lock request 815 */ 816 static int fuse_copy_fill(struct fuse_copy_state *cs) 817 { 818 struct page *page; 819 int err; 820 821 err = unlock_request(cs->req); 822 if (err) 823 return err; 824 825 fuse_copy_finish(cs); 826 if (cs->pipebufs) { 827 struct pipe_buffer *buf = cs->pipebufs; 828 829 if (!cs->write) { 830 err = pipe_buf_confirm(cs->pipe, buf); 831 if (err) 832 return err; 833 834 BUG_ON(!cs->nr_segs); 835 cs->currbuf = buf; 836 cs->pg = buf->page; 837 cs->offset = buf->offset; 838 cs->len = buf->len; 839 cs->pipebufs++; 840 cs->nr_segs--; 841 } else { 842 if (cs->nr_segs == cs->pipe->buffers) 843 return -EIO; 844 845 page = alloc_page(GFP_HIGHUSER); 846 if (!page) 847 return -ENOMEM; 848 849 buf->page = page; 850 buf->offset = 0; 851 buf->len = 0; 852 853 cs->currbuf = buf; 854 cs->pg = page; 855 cs->offset = 0; 856 cs->len = PAGE_SIZE; 857 cs->pipebufs++; 858 cs->nr_segs++; 859 } 860 } else { 861 size_t off; 862 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off); 863 if (err < 0) 864 return err; 865 BUG_ON(!err); 866 cs->len = err; 867 cs->offset = off; 868 cs->pg = page; 869 iov_iter_advance(cs->iter, err); 870 } 871 872 return lock_request(cs->req); 873 } 874 875 /* Do as much copy to/from userspace buffer as we can */ 876 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 877 { 878 unsigned ncpy = min(*size, cs->len); 879 if (val) { 880 void *pgaddr = kmap_atomic(cs->pg); 881 void *buf = pgaddr + cs->offset; 882 883 if (cs->write) 884 memcpy(buf, *val, ncpy); 885 else 886 memcpy(*val, buf, ncpy); 887 888 kunmap_atomic(pgaddr); 889 *val += ncpy; 890 } 891 *size -= ncpy; 892 cs->len -= ncpy; 893 cs->offset += ncpy; 894 return ncpy; 895 } 896 897 static int fuse_check_page(struct page *page) 898 { 899 if (page_mapcount(page) || 900 page->mapping != NULL || 901 page_count(page) != 1 || 902 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 903 ~(1 << PG_locked | 904 1 << PG_referenced | 905 1 << PG_uptodate | 906 1 << PG_lru | 907 1 << PG_active | 908 1 << PG_reclaim))) { 909 pr_warn("trying to steal weird page\n"); 910 pr_warn(" page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping); 911 return 1; 912 } 913 return 0; 914 } 915 916 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 917 { 918 int err; 919 struct page *oldpage = *pagep; 920 struct page *newpage; 921 struct pipe_buffer *buf = cs->pipebufs; 922 923 err = unlock_request(cs->req); 924 if (err) 925 return err; 926 927 fuse_copy_finish(cs); 928 929 err = pipe_buf_confirm(cs->pipe, buf); 930 if (err) 931 return err; 932 933 BUG_ON(!cs->nr_segs); 934 cs->currbuf = buf; 935 cs->len = buf->len; 936 cs->pipebufs++; 937 cs->nr_segs--; 938 939 if (cs->len != PAGE_SIZE) 940 goto out_fallback; 941 942 if (pipe_buf_steal(cs->pipe, buf) != 0) 943 goto out_fallback; 944 945 newpage = buf->page; 946 947 if (!PageUptodate(newpage)) 948 SetPageUptodate(newpage); 949 950 ClearPageMappedToDisk(newpage); 951 952 if (fuse_check_page(newpage) != 0) 953 goto out_fallback_unlock; 954 955 /* 956 * This is a new and locked page, it shouldn't be mapped or 957 * have any special flags on it 958 */ 959 if (WARN_ON(page_mapped(oldpage))) 960 goto out_fallback_unlock; 961 if (WARN_ON(page_has_private(oldpage))) 962 goto out_fallback_unlock; 963 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 964 goto out_fallback_unlock; 965 if (WARN_ON(PageMlocked(oldpage))) 966 goto out_fallback_unlock; 967 968 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); 969 if (err) { 970 unlock_page(newpage); 971 return err; 972 } 973 974 get_page(newpage); 975 976 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 977 lru_cache_add_file(newpage); 978 979 err = 0; 980 spin_lock(&cs->req->waitq.lock); 981 if (test_bit(FR_ABORTED, &cs->req->flags)) 982 err = -ENOENT; 983 else 984 *pagep = newpage; 985 spin_unlock(&cs->req->waitq.lock); 986 987 if (err) { 988 unlock_page(newpage); 989 put_page(newpage); 990 return err; 991 } 992 993 unlock_page(oldpage); 994 put_page(oldpage); 995 cs->len = 0; 996 997 return 0; 998 999 out_fallback_unlock: 1000 unlock_page(newpage); 1001 out_fallback: 1002 cs->pg = buf->page; 1003 cs->offset = buf->offset; 1004 1005 err = lock_request(cs->req); 1006 if (err) 1007 return err; 1008 1009 return 1; 1010 } 1011 1012 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 1013 unsigned offset, unsigned count) 1014 { 1015 struct pipe_buffer *buf; 1016 int err; 1017 1018 if (cs->nr_segs == cs->pipe->buffers) 1019 return -EIO; 1020 1021 err = unlock_request(cs->req); 1022 if (err) 1023 return err; 1024 1025 fuse_copy_finish(cs); 1026 1027 buf = cs->pipebufs; 1028 get_page(page); 1029 buf->page = page; 1030 buf->offset = offset; 1031 buf->len = count; 1032 1033 cs->pipebufs++; 1034 cs->nr_segs++; 1035 cs->len = 0; 1036 1037 return 0; 1038 } 1039 1040 /* 1041 * Copy a page in the request to/from the userspace buffer. Must be 1042 * done atomically 1043 */ 1044 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 1045 unsigned offset, unsigned count, int zeroing) 1046 { 1047 int err; 1048 struct page *page = *pagep; 1049 1050 if (page && zeroing && count < PAGE_SIZE) 1051 clear_highpage(page); 1052 1053 while (count) { 1054 if (cs->write && cs->pipebufs && page) { 1055 return fuse_ref_page(cs, page, offset, count); 1056 } else if (!cs->len) { 1057 if (cs->move_pages && page && 1058 offset == 0 && count == PAGE_SIZE) { 1059 err = fuse_try_move_page(cs, pagep); 1060 if (err <= 0) 1061 return err; 1062 } else { 1063 err = fuse_copy_fill(cs); 1064 if (err) 1065 return err; 1066 } 1067 } 1068 if (page) { 1069 void *mapaddr = kmap_atomic(page); 1070 void *buf = mapaddr + offset; 1071 offset += fuse_copy_do(cs, &buf, &count); 1072 kunmap_atomic(mapaddr); 1073 } else 1074 offset += fuse_copy_do(cs, NULL, &count); 1075 } 1076 if (page && !cs->write) 1077 flush_dcache_page(page); 1078 return 0; 1079 } 1080 1081 /* Copy pages in the request to/from userspace buffer */ 1082 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 1083 int zeroing) 1084 { 1085 unsigned i; 1086 struct fuse_req *req = cs->req; 1087 1088 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { 1089 int err; 1090 unsigned offset = req->page_descs[i].offset; 1091 unsigned count = min(nbytes, req->page_descs[i].length); 1092 1093 err = fuse_copy_page(cs, &req->pages[i], offset, count, 1094 zeroing); 1095 if (err) 1096 return err; 1097 1098 nbytes -= count; 1099 } 1100 return 0; 1101 } 1102 1103 /* Copy a single argument in the request to/from userspace buffer */ 1104 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 1105 { 1106 while (size) { 1107 if (!cs->len) { 1108 int err = fuse_copy_fill(cs); 1109 if (err) 1110 return err; 1111 } 1112 fuse_copy_do(cs, &val, &size); 1113 } 1114 return 0; 1115 } 1116 1117 /* Copy request arguments to/from userspace buffer */ 1118 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 1119 unsigned argpages, struct fuse_arg *args, 1120 int zeroing) 1121 { 1122 int err = 0; 1123 unsigned i; 1124 1125 for (i = 0; !err && i < numargs; i++) { 1126 struct fuse_arg *arg = &args[i]; 1127 if (i == numargs - 1 && argpages) 1128 err = fuse_copy_pages(cs, arg->size, zeroing); 1129 else 1130 err = fuse_copy_one(cs, arg->value, arg->size); 1131 } 1132 return err; 1133 } 1134 1135 static int forget_pending(struct fuse_iqueue *fiq) 1136 { 1137 return fiq->forget_list_head.next != NULL; 1138 } 1139 1140 static int request_pending(struct fuse_iqueue *fiq) 1141 { 1142 return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) || 1143 forget_pending(fiq); 1144 } 1145 1146 /* 1147 * Transfer an interrupt request to userspace 1148 * 1149 * Unlike other requests this is assembled on demand, without a need 1150 * to allocate a separate fuse_req structure. 1151 * 1152 * Called with fiq->waitq.lock held, releases it 1153 */ 1154 static int fuse_read_interrupt(struct fuse_iqueue *fiq, 1155 struct fuse_copy_state *cs, 1156 size_t nbytes, struct fuse_req *req) 1157 __releases(fiq->waitq.lock) 1158 { 1159 struct fuse_in_header ih; 1160 struct fuse_interrupt_in arg; 1161 unsigned reqsize = sizeof(ih) + sizeof(arg); 1162 int err; 1163 1164 list_del_init(&req->intr_entry); 1165 memset(&ih, 0, sizeof(ih)); 1166 memset(&arg, 0, sizeof(arg)); 1167 ih.len = reqsize; 1168 ih.opcode = FUSE_INTERRUPT; 1169 ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT); 1170 arg.unique = req->in.h.unique; 1171 1172 spin_unlock(&fiq->waitq.lock); 1173 if (nbytes < reqsize) 1174 return -EINVAL; 1175 1176 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1177 if (!err) 1178 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1179 fuse_copy_finish(cs); 1180 1181 return err ? err : reqsize; 1182 } 1183 1184 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq, 1185 unsigned max, 1186 unsigned *countp) 1187 { 1188 struct fuse_forget_link *head = fiq->forget_list_head.next; 1189 struct fuse_forget_link **newhead = &head; 1190 unsigned count; 1191 1192 for (count = 0; *newhead != NULL && count < max; count++) 1193 newhead = &(*newhead)->next; 1194 1195 fiq->forget_list_head.next = *newhead; 1196 *newhead = NULL; 1197 if (fiq->forget_list_head.next == NULL) 1198 fiq->forget_list_tail = &fiq->forget_list_head; 1199 1200 if (countp != NULL) 1201 *countp = count; 1202 1203 return head; 1204 } 1205 1206 static int fuse_read_single_forget(struct fuse_iqueue *fiq, 1207 struct fuse_copy_state *cs, 1208 size_t nbytes) 1209 __releases(fiq->waitq.lock) 1210 { 1211 int err; 1212 struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL); 1213 struct fuse_forget_in arg = { 1214 .nlookup = forget->forget_one.nlookup, 1215 }; 1216 struct fuse_in_header ih = { 1217 .opcode = FUSE_FORGET, 1218 .nodeid = forget->forget_one.nodeid, 1219 .unique = fuse_get_unique(fiq), 1220 .len = sizeof(ih) + sizeof(arg), 1221 }; 1222 1223 spin_unlock(&fiq->waitq.lock); 1224 kfree(forget); 1225 if (nbytes < ih.len) 1226 return -EINVAL; 1227 1228 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1229 if (!err) 1230 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1231 fuse_copy_finish(cs); 1232 1233 if (err) 1234 return err; 1235 1236 return ih.len; 1237 } 1238 1239 static int fuse_read_batch_forget(struct fuse_iqueue *fiq, 1240 struct fuse_copy_state *cs, size_t nbytes) 1241 __releases(fiq->waitq.lock) 1242 { 1243 int err; 1244 unsigned max_forgets; 1245 unsigned count; 1246 struct fuse_forget_link *head; 1247 struct fuse_batch_forget_in arg = { .count = 0 }; 1248 struct fuse_in_header ih = { 1249 .opcode = FUSE_BATCH_FORGET, 1250 .unique = fuse_get_unique(fiq), 1251 .len = sizeof(ih) + sizeof(arg), 1252 }; 1253 1254 if (nbytes < ih.len) { 1255 spin_unlock(&fiq->waitq.lock); 1256 return -EINVAL; 1257 } 1258 1259 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1260 head = dequeue_forget(fiq, max_forgets, &count); 1261 spin_unlock(&fiq->waitq.lock); 1262 1263 arg.count = count; 1264 ih.len += count * sizeof(struct fuse_forget_one); 1265 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1266 if (!err) 1267 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1268 1269 while (head) { 1270 struct fuse_forget_link *forget = head; 1271 1272 if (!err) { 1273 err = fuse_copy_one(cs, &forget->forget_one, 1274 sizeof(forget->forget_one)); 1275 } 1276 head = forget->next; 1277 kfree(forget); 1278 } 1279 1280 fuse_copy_finish(cs); 1281 1282 if (err) 1283 return err; 1284 1285 return ih.len; 1286 } 1287 1288 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq, 1289 struct fuse_copy_state *cs, 1290 size_t nbytes) 1291 __releases(fiq->waitq.lock) 1292 { 1293 if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL) 1294 return fuse_read_single_forget(fiq, cs, nbytes); 1295 else 1296 return fuse_read_batch_forget(fiq, cs, nbytes); 1297 } 1298 1299 /* 1300 * Read a single request into the userspace filesystem's buffer. This 1301 * function waits until a request is available, then removes it from 1302 * the pending list and copies request data to userspace buffer. If 1303 * no reply is needed (FORGET) or request has been aborted or there 1304 * was an error during the copying then it's finished by calling 1305 * request_end(). Otherwise add it to the processing list, and set 1306 * the 'sent' flag. 1307 */ 1308 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, 1309 struct fuse_copy_state *cs, size_t nbytes) 1310 { 1311 ssize_t err; 1312 struct fuse_conn *fc = fud->fc; 1313 struct fuse_iqueue *fiq = &fc->iq; 1314 struct fuse_pqueue *fpq = &fud->pq; 1315 struct fuse_req *req; 1316 struct fuse_in *in; 1317 unsigned reqsize; 1318 unsigned int hash; 1319 1320 restart: 1321 spin_lock(&fiq->waitq.lock); 1322 err = -EAGAIN; 1323 if ((file->f_flags & O_NONBLOCK) && fiq->connected && 1324 !request_pending(fiq)) 1325 goto err_unlock; 1326 1327 err = wait_event_interruptible_exclusive_locked(fiq->waitq, 1328 !fiq->connected || request_pending(fiq)); 1329 if (err) 1330 goto err_unlock; 1331 1332 if (!fiq->connected) { 1333 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1334 goto err_unlock; 1335 } 1336 1337 if (!list_empty(&fiq->interrupts)) { 1338 req = list_entry(fiq->interrupts.next, struct fuse_req, 1339 intr_entry); 1340 return fuse_read_interrupt(fiq, cs, nbytes, req); 1341 } 1342 1343 if (forget_pending(fiq)) { 1344 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0) 1345 return fuse_read_forget(fc, fiq, cs, nbytes); 1346 1347 if (fiq->forget_batch <= -8) 1348 fiq->forget_batch = 16; 1349 } 1350 1351 req = list_entry(fiq->pending.next, struct fuse_req, list); 1352 clear_bit(FR_PENDING, &req->flags); 1353 list_del_init(&req->list); 1354 spin_unlock(&fiq->waitq.lock); 1355 1356 in = &req->in; 1357 reqsize = in->h.len; 1358 1359 /* If request is too large, reply with an error and restart the read */ 1360 if (nbytes < reqsize) { 1361 req->out.h.error = -EIO; 1362 /* SETXATTR is special, since it may contain too large data */ 1363 if (in->h.opcode == FUSE_SETXATTR) 1364 req->out.h.error = -E2BIG; 1365 request_end(fc, req); 1366 goto restart; 1367 } 1368 spin_lock(&fpq->lock); 1369 list_add(&req->list, &fpq->io); 1370 spin_unlock(&fpq->lock); 1371 cs->req = req; 1372 err = fuse_copy_one(cs, &in->h, sizeof(in->h)); 1373 if (!err) 1374 err = fuse_copy_args(cs, in->numargs, in->argpages, 1375 (struct fuse_arg *) in->args, 0); 1376 fuse_copy_finish(cs); 1377 spin_lock(&fpq->lock); 1378 clear_bit(FR_LOCKED, &req->flags); 1379 if (!fpq->connected) { 1380 err = fc->aborted ? -ECONNABORTED : -ENODEV; 1381 goto out_end; 1382 } 1383 if (err) { 1384 req->out.h.error = -EIO; 1385 goto out_end; 1386 } 1387 if (!test_bit(FR_ISREPLY, &req->flags)) { 1388 err = reqsize; 1389 goto out_end; 1390 } 1391 hash = fuse_req_hash(req->in.h.unique); 1392 list_move_tail(&req->list, &fpq->processing[hash]); 1393 __fuse_get_request(req); 1394 set_bit(FR_SENT, &req->flags); 1395 spin_unlock(&fpq->lock); 1396 /* matches barrier in request_wait_answer() */ 1397 smp_mb__after_atomic(); 1398 if (test_bit(FR_INTERRUPTED, &req->flags)) 1399 queue_interrupt(fiq, req); 1400 fuse_put_request(fc, req); 1401 1402 return reqsize; 1403 1404 out_end: 1405 if (!test_bit(FR_PRIVATE, &req->flags)) 1406 list_del_init(&req->list); 1407 spin_unlock(&fpq->lock); 1408 request_end(fc, req); 1409 return err; 1410 1411 err_unlock: 1412 spin_unlock(&fiq->waitq.lock); 1413 return err; 1414 } 1415 1416 static int fuse_dev_open(struct inode *inode, struct file *file) 1417 { 1418 /* 1419 * The fuse device's file's private_data is used to hold 1420 * the fuse_conn(ection) when it is mounted, and is used to 1421 * keep track of whether the file has been mounted already. 1422 */ 1423 file->private_data = NULL; 1424 return 0; 1425 } 1426 1427 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to) 1428 { 1429 struct fuse_copy_state cs; 1430 struct file *file = iocb->ki_filp; 1431 struct fuse_dev *fud = fuse_get_dev(file); 1432 1433 if (!fud) 1434 return -EPERM; 1435 1436 if (!iter_is_iovec(to)) 1437 return -EINVAL; 1438 1439 fuse_copy_init(&cs, 1, to); 1440 1441 return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to)); 1442 } 1443 1444 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1445 struct pipe_inode_info *pipe, 1446 size_t len, unsigned int flags) 1447 { 1448 int total, ret; 1449 int page_nr = 0; 1450 struct pipe_buffer *bufs; 1451 struct fuse_copy_state cs; 1452 struct fuse_dev *fud = fuse_get_dev(in); 1453 1454 if (!fud) 1455 return -EPERM; 1456 1457 bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer), 1458 GFP_KERNEL); 1459 if (!bufs) 1460 return -ENOMEM; 1461 1462 fuse_copy_init(&cs, 1, NULL); 1463 cs.pipebufs = bufs; 1464 cs.pipe = pipe; 1465 ret = fuse_dev_do_read(fud, in, &cs, len); 1466 if (ret < 0) 1467 goto out; 1468 1469 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) { 1470 ret = -EIO; 1471 goto out; 1472 } 1473 1474 for (ret = total = 0; page_nr < cs.nr_segs; total += ret) { 1475 /* 1476 * Need to be careful about this. Having buf->ops in module 1477 * code can Oops if the buffer persists after module unload. 1478 */ 1479 bufs[page_nr].ops = &nosteal_pipe_buf_ops; 1480 bufs[page_nr].flags = 0; 1481 ret = add_to_pipe(pipe, &bufs[page_nr++]); 1482 if (unlikely(ret < 0)) 1483 break; 1484 } 1485 if (total) 1486 ret = total; 1487 out: 1488 for (; page_nr < cs.nr_segs; page_nr++) 1489 put_page(bufs[page_nr].page); 1490 1491 kvfree(bufs); 1492 return ret; 1493 } 1494 1495 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1496 struct fuse_copy_state *cs) 1497 { 1498 struct fuse_notify_poll_wakeup_out outarg; 1499 int err = -EINVAL; 1500 1501 if (size != sizeof(outarg)) 1502 goto err; 1503 1504 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1505 if (err) 1506 goto err; 1507 1508 fuse_copy_finish(cs); 1509 return fuse_notify_poll_wakeup(fc, &outarg); 1510 1511 err: 1512 fuse_copy_finish(cs); 1513 return err; 1514 } 1515 1516 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1517 struct fuse_copy_state *cs) 1518 { 1519 struct fuse_notify_inval_inode_out outarg; 1520 int err = -EINVAL; 1521 1522 if (size != sizeof(outarg)) 1523 goto err; 1524 1525 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1526 if (err) 1527 goto err; 1528 fuse_copy_finish(cs); 1529 1530 down_read(&fc->killsb); 1531 err = -ENOENT; 1532 if (fc->sb) { 1533 err = fuse_reverse_inval_inode(fc->sb, outarg.ino, 1534 outarg.off, outarg.len); 1535 } 1536 up_read(&fc->killsb); 1537 return err; 1538 1539 err: 1540 fuse_copy_finish(cs); 1541 return err; 1542 } 1543 1544 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1545 struct fuse_copy_state *cs) 1546 { 1547 struct fuse_notify_inval_entry_out outarg; 1548 int err = -ENOMEM; 1549 char *buf; 1550 struct qstr name; 1551 1552 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1553 if (!buf) 1554 goto err; 1555 1556 err = -EINVAL; 1557 if (size < sizeof(outarg)) 1558 goto err; 1559 1560 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1561 if (err) 1562 goto err; 1563 1564 err = -ENAMETOOLONG; 1565 if (outarg.namelen > FUSE_NAME_MAX) 1566 goto err; 1567 1568 err = -EINVAL; 1569 if (size != sizeof(outarg) + outarg.namelen + 1) 1570 goto err; 1571 1572 name.name = buf; 1573 name.len = outarg.namelen; 1574 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1575 if (err) 1576 goto err; 1577 fuse_copy_finish(cs); 1578 buf[outarg.namelen] = 0; 1579 1580 down_read(&fc->killsb); 1581 err = -ENOENT; 1582 if (fc->sb) 1583 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name); 1584 up_read(&fc->killsb); 1585 kfree(buf); 1586 return err; 1587 1588 err: 1589 kfree(buf); 1590 fuse_copy_finish(cs); 1591 return err; 1592 } 1593 1594 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1595 struct fuse_copy_state *cs) 1596 { 1597 struct fuse_notify_delete_out outarg; 1598 int err = -ENOMEM; 1599 char *buf; 1600 struct qstr name; 1601 1602 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1603 if (!buf) 1604 goto err; 1605 1606 err = -EINVAL; 1607 if (size < sizeof(outarg)) 1608 goto err; 1609 1610 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1611 if (err) 1612 goto err; 1613 1614 err = -ENAMETOOLONG; 1615 if (outarg.namelen > FUSE_NAME_MAX) 1616 goto err; 1617 1618 err = -EINVAL; 1619 if (size != sizeof(outarg) + outarg.namelen + 1) 1620 goto err; 1621 1622 name.name = buf; 1623 name.len = outarg.namelen; 1624 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1625 if (err) 1626 goto err; 1627 fuse_copy_finish(cs); 1628 buf[outarg.namelen] = 0; 1629 1630 down_read(&fc->killsb); 1631 err = -ENOENT; 1632 if (fc->sb) 1633 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 1634 outarg.child, &name); 1635 up_read(&fc->killsb); 1636 kfree(buf); 1637 return err; 1638 1639 err: 1640 kfree(buf); 1641 fuse_copy_finish(cs); 1642 return err; 1643 } 1644 1645 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1646 struct fuse_copy_state *cs) 1647 { 1648 struct fuse_notify_store_out outarg; 1649 struct inode *inode; 1650 struct address_space *mapping; 1651 u64 nodeid; 1652 int err; 1653 pgoff_t index; 1654 unsigned int offset; 1655 unsigned int num; 1656 loff_t file_size; 1657 loff_t end; 1658 1659 err = -EINVAL; 1660 if (size < sizeof(outarg)) 1661 goto out_finish; 1662 1663 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1664 if (err) 1665 goto out_finish; 1666 1667 err = -EINVAL; 1668 if (size - sizeof(outarg) != outarg.size) 1669 goto out_finish; 1670 1671 nodeid = outarg.nodeid; 1672 1673 down_read(&fc->killsb); 1674 1675 err = -ENOENT; 1676 if (!fc->sb) 1677 goto out_up_killsb; 1678 1679 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1680 if (!inode) 1681 goto out_up_killsb; 1682 1683 mapping = inode->i_mapping; 1684 index = outarg.offset >> PAGE_SHIFT; 1685 offset = outarg.offset & ~PAGE_MASK; 1686 file_size = i_size_read(inode); 1687 end = outarg.offset + outarg.size; 1688 if (end > file_size) { 1689 file_size = end; 1690 fuse_write_update_size(inode, file_size); 1691 } 1692 1693 num = outarg.size; 1694 while (num) { 1695 struct page *page; 1696 unsigned int this_num; 1697 1698 err = -ENOMEM; 1699 page = find_or_create_page(mapping, index, 1700 mapping_gfp_mask(mapping)); 1701 if (!page) 1702 goto out_iput; 1703 1704 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1705 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1706 if (!err && offset == 0 && 1707 (this_num == PAGE_SIZE || file_size == end)) 1708 SetPageUptodate(page); 1709 unlock_page(page); 1710 put_page(page); 1711 1712 if (err) 1713 goto out_iput; 1714 1715 num -= this_num; 1716 offset = 0; 1717 index++; 1718 } 1719 1720 err = 0; 1721 1722 out_iput: 1723 iput(inode); 1724 out_up_killsb: 1725 up_read(&fc->killsb); 1726 out_finish: 1727 fuse_copy_finish(cs); 1728 return err; 1729 } 1730 1731 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req) 1732 { 1733 release_pages(req->pages, req->num_pages); 1734 } 1735 1736 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, 1737 struct fuse_notify_retrieve_out *outarg) 1738 { 1739 int err; 1740 struct address_space *mapping = inode->i_mapping; 1741 struct fuse_req *req; 1742 pgoff_t index; 1743 loff_t file_size; 1744 unsigned int num; 1745 unsigned int offset; 1746 size_t total_len = 0; 1747 unsigned int num_pages; 1748 1749 offset = outarg->offset & ~PAGE_MASK; 1750 file_size = i_size_read(inode); 1751 1752 num = min(outarg->size, fc->max_write); 1753 if (outarg->offset > file_size) 1754 num = 0; 1755 else if (outarg->offset + num > file_size) 1756 num = file_size - outarg->offset; 1757 1758 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1759 num_pages = min(num_pages, fc->max_pages); 1760 1761 req = fuse_get_req(fc, num_pages); 1762 if (IS_ERR(req)) 1763 return PTR_ERR(req); 1764 1765 req->in.h.opcode = FUSE_NOTIFY_REPLY; 1766 req->in.h.nodeid = outarg->nodeid; 1767 req->in.numargs = 2; 1768 req->in.argpages = 1; 1769 req->end = fuse_retrieve_end; 1770 1771 index = outarg->offset >> PAGE_SHIFT; 1772 1773 while (num && req->num_pages < num_pages) { 1774 struct page *page; 1775 unsigned int this_num; 1776 1777 page = find_get_page(mapping, index); 1778 if (!page) 1779 break; 1780 1781 this_num = min_t(unsigned, num, PAGE_SIZE - offset); 1782 req->pages[req->num_pages] = page; 1783 req->page_descs[req->num_pages].offset = offset; 1784 req->page_descs[req->num_pages].length = this_num; 1785 req->num_pages++; 1786 1787 offset = 0; 1788 num -= this_num; 1789 total_len += this_num; 1790 index++; 1791 } 1792 req->misc.retrieve_in.offset = outarg->offset; 1793 req->misc.retrieve_in.size = total_len; 1794 req->in.args[0].size = sizeof(req->misc.retrieve_in); 1795 req->in.args[0].value = &req->misc.retrieve_in; 1796 req->in.args[1].size = total_len; 1797 1798 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique); 1799 if (err) { 1800 fuse_retrieve_end(fc, req); 1801 fuse_put_request(fc, req); 1802 } 1803 1804 return err; 1805 } 1806 1807 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1808 struct fuse_copy_state *cs) 1809 { 1810 struct fuse_notify_retrieve_out outarg; 1811 struct inode *inode; 1812 int err; 1813 1814 err = -EINVAL; 1815 if (size != sizeof(outarg)) 1816 goto copy_finish; 1817 1818 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1819 if (err) 1820 goto copy_finish; 1821 1822 fuse_copy_finish(cs); 1823 1824 down_read(&fc->killsb); 1825 err = -ENOENT; 1826 if (fc->sb) { 1827 u64 nodeid = outarg.nodeid; 1828 1829 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1830 if (inode) { 1831 err = fuse_retrieve(fc, inode, &outarg); 1832 iput(inode); 1833 } 1834 } 1835 up_read(&fc->killsb); 1836 1837 return err; 1838 1839 copy_finish: 1840 fuse_copy_finish(cs); 1841 return err; 1842 } 1843 1844 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1845 unsigned int size, struct fuse_copy_state *cs) 1846 { 1847 /* Don't try to move pages (yet) */ 1848 cs->move_pages = 0; 1849 1850 switch (code) { 1851 case FUSE_NOTIFY_POLL: 1852 return fuse_notify_poll(fc, size, cs); 1853 1854 case FUSE_NOTIFY_INVAL_INODE: 1855 return fuse_notify_inval_inode(fc, size, cs); 1856 1857 case FUSE_NOTIFY_INVAL_ENTRY: 1858 return fuse_notify_inval_entry(fc, size, cs); 1859 1860 case FUSE_NOTIFY_STORE: 1861 return fuse_notify_store(fc, size, cs); 1862 1863 case FUSE_NOTIFY_RETRIEVE: 1864 return fuse_notify_retrieve(fc, size, cs); 1865 1866 case FUSE_NOTIFY_DELETE: 1867 return fuse_notify_delete(fc, size, cs); 1868 1869 default: 1870 fuse_copy_finish(cs); 1871 return -EINVAL; 1872 } 1873 } 1874 1875 /* Look up request on processing list by unique ID */ 1876 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique) 1877 { 1878 unsigned int hash = fuse_req_hash(unique); 1879 struct fuse_req *req; 1880 1881 list_for_each_entry(req, &fpq->processing[hash], list) { 1882 if (req->in.h.unique == unique) 1883 return req; 1884 } 1885 return NULL; 1886 } 1887 1888 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, 1889 unsigned nbytes) 1890 { 1891 unsigned reqsize = sizeof(struct fuse_out_header); 1892 1893 if (out->h.error) 1894 return nbytes != reqsize ? -EINVAL : 0; 1895 1896 reqsize += len_args(out->numargs, out->args); 1897 1898 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) 1899 return -EINVAL; 1900 else if (reqsize > nbytes) { 1901 struct fuse_arg *lastarg = &out->args[out->numargs-1]; 1902 unsigned diffsize = reqsize - nbytes; 1903 if (diffsize > lastarg->size) 1904 return -EINVAL; 1905 lastarg->size -= diffsize; 1906 } 1907 return fuse_copy_args(cs, out->numargs, out->argpages, out->args, 1908 out->page_zeroing); 1909 } 1910 1911 /* 1912 * Write a single reply to a request. First the header is copied from 1913 * the write buffer. The request is then searched on the processing 1914 * list by the unique ID found in the header. If found, then remove 1915 * it from the list and copy the rest of the buffer to the request. 1916 * The request is finished by calling request_end() 1917 */ 1918 static ssize_t fuse_dev_do_write(struct fuse_dev *fud, 1919 struct fuse_copy_state *cs, size_t nbytes) 1920 { 1921 int err; 1922 struct fuse_conn *fc = fud->fc; 1923 struct fuse_pqueue *fpq = &fud->pq; 1924 struct fuse_req *req; 1925 struct fuse_out_header oh; 1926 1927 err = -EINVAL; 1928 if (nbytes < sizeof(struct fuse_out_header)) 1929 goto out; 1930 1931 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1932 if (err) 1933 goto copy_finish; 1934 1935 err = -EINVAL; 1936 if (oh.len != nbytes) 1937 goto copy_finish; 1938 1939 /* 1940 * Zero oh.unique indicates unsolicited notification message 1941 * and error contains notification code. 1942 */ 1943 if (!oh.unique) { 1944 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1945 goto out; 1946 } 1947 1948 err = -EINVAL; 1949 if (oh.error <= -1000 || oh.error > 0) 1950 goto copy_finish; 1951 1952 spin_lock(&fpq->lock); 1953 req = NULL; 1954 if (fpq->connected) 1955 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT); 1956 1957 err = -ENOENT; 1958 if (!req) { 1959 spin_unlock(&fpq->lock); 1960 goto copy_finish; 1961 } 1962 1963 /* Is it an interrupt reply ID? */ 1964 if (oh.unique & FUSE_INT_REQ_BIT) { 1965 __fuse_get_request(req); 1966 spin_unlock(&fpq->lock); 1967 1968 err = 0; 1969 if (nbytes != sizeof(struct fuse_out_header)) 1970 err = -EINVAL; 1971 else if (oh.error == -ENOSYS) 1972 fc->no_interrupt = 1; 1973 else if (oh.error == -EAGAIN) 1974 err = queue_interrupt(&fc->iq, req); 1975 1976 fuse_put_request(fc, req); 1977 1978 goto copy_finish; 1979 } 1980 1981 clear_bit(FR_SENT, &req->flags); 1982 list_move(&req->list, &fpq->io); 1983 req->out.h = oh; 1984 set_bit(FR_LOCKED, &req->flags); 1985 spin_unlock(&fpq->lock); 1986 cs->req = req; 1987 if (!req->out.page_replace) 1988 cs->move_pages = 0; 1989 1990 err = copy_out_args(cs, &req->out, nbytes); 1991 fuse_copy_finish(cs); 1992 1993 spin_lock(&fpq->lock); 1994 clear_bit(FR_LOCKED, &req->flags); 1995 if (!fpq->connected) 1996 err = -ENOENT; 1997 else if (err) 1998 req->out.h.error = -EIO; 1999 if (!test_bit(FR_PRIVATE, &req->flags)) 2000 list_del_init(&req->list); 2001 spin_unlock(&fpq->lock); 2002 2003 request_end(fc, req); 2004 out: 2005 return err ? err : nbytes; 2006 2007 copy_finish: 2008 fuse_copy_finish(cs); 2009 goto out; 2010 } 2011 2012 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from) 2013 { 2014 struct fuse_copy_state cs; 2015 struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp); 2016 2017 if (!fud) 2018 return -EPERM; 2019 2020 if (!iter_is_iovec(from)) 2021 return -EINVAL; 2022 2023 fuse_copy_init(&cs, 0, from); 2024 2025 return fuse_dev_do_write(fud, &cs, iov_iter_count(from)); 2026 } 2027 2028 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 2029 struct file *out, loff_t *ppos, 2030 size_t len, unsigned int flags) 2031 { 2032 unsigned nbuf; 2033 unsigned idx; 2034 struct pipe_buffer *bufs; 2035 struct fuse_copy_state cs; 2036 struct fuse_dev *fud; 2037 size_t rem; 2038 ssize_t ret; 2039 2040 fud = fuse_get_dev(out); 2041 if (!fud) 2042 return -EPERM; 2043 2044 pipe_lock(pipe); 2045 2046 bufs = kvmalloc_array(pipe->nrbufs, sizeof(struct pipe_buffer), 2047 GFP_KERNEL); 2048 if (!bufs) { 2049 pipe_unlock(pipe); 2050 return -ENOMEM; 2051 } 2052 2053 nbuf = 0; 2054 rem = 0; 2055 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) 2056 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; 2057 2058 ret = -EINVAL; 2059 if (rem < len) 2060 goto out_free; 2061 2062 rem = len; 2063 while (rem) { 2064 struct pipe_buffer *ibuf; 2065 struct pipe_buffer *obuf; 2066 2067 BUG_ON(nbuf >= pipe->buffers); 2068 BUG_ON(!pipe->nrbufs); 2069 ibuf = &pipe->bufs[pipe->curbuf]; 2070 obuf = &bufs[nbuf]; 2071 2072 if (rem >= ibuf->len) { 2073 *obuf = *ibuf; 2074 ibuf->ops = NULL; 2075 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 2076 pipe->nrbufs--; 2077 } else { 2078 if (!pipe_buf_get(pipe, ibuf)) 2079 goto out_free; 2080 2081 *obuf = *ibuf; 2082 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 2083 obuf->len = rem; 2084 ibuf->offset += obuf->len; 2085 ibuf->len -= obuf->len; 2086 } 2087 nbuf++; 2088 rem -= obuf->len; 2089 } 2090 pipe_unlock(pipe); 2091 2092 fuse_copy_init(&cs, 0, NULL); 2093 cs.pipebufs = bufs; 2094 cs.nr_segs = nbuf; 2095 cs.pipe = pipe; 2096 2097 if (flags & SPLICE_F_MOVE) 2098 cs.move_pages = 1; 2099 2100 ret = fuse_dev_do_write(fud, &cs, len); 2101 2102 pipe_lock(pipe); 2103 out_free: 2104 for (idx = 0; idx < nbuf; idx++) 2105 pipe_buf_release(pipe, &bufs[idx]); 2106 pipe_unlock(pipe); 2107 2108 kvfree(bufs); 2109 return ret; 2110 } 2111 2112 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait) 2113 { 2114 __poll_t mask = EPOLLOUT | EPOLLWRNORM; 2115 struct fuse_iqueue *fiq; 2116 struct fuse_dev *fud = fuse_get_dev(file); 2117 2118 if (!fud) 2119 return EPOLLERR; 2120 2121 fiq = &fud->fc->iq; 2122 poll_wait(file, &fiq->waitq, wait); 2123 2124 spin_lock(&fiq->waitq.lock); 2125 if (!fiq->connected) 2126 mask = EPOLLERR; 2127 else if (request_pending(fiq)) 2128 mask |= EPOLLIN | EPOLLRDNORM; 2129 spin_unlock(&fiq->waitq.lock); 2130 2131 return mask; 2132 } 2133 2134 /* Abort all requests on the given list (pending or processing) */ 2135 static void end_requests(struct fuse_conn *fc, struct list_head *head) 2136 { 2137 while (!list_empty(head)) { 2138 struct fuse_req *req; 2139 req = list_entry(head->next, struct fuse_req, list); 2140 req->out.h.error = -ECONNABORTED; 2141 clear_bit(FR_SENT, &req->flags); 2142 list_del_init(&req->list); 2143 request_end(fc, req); 2144 } 2145 } 2146 2147 static void end_polls(struct fuse_conn *fc) 2148 { 2149 struct rb_node *p; 2150 2151 p = rb_first(&fc->polled_files); 2152 2153 while (p) { 2154 struct fuse_file *ff; 2155 ff = rb_entry(p, struct fuse_file, polled_node); 2156 wake_up_interruptible_all(&ff->poll_wait); 2157 2158 p = rb_next(p); 2159 } 2160 } 2161 2162 /* 2163 * Abort all requests. 2164 * 2165 * Emergency exit in case of a malicious or accidental deadlock, or just a hung 2166 * filesystem. 2167 * 2168 * The same effect is usually achievable through killing the filesystem daemon 2169 * and all users of the filesystem. The exception is the combination of an 2170 * asynchronous request and the tricky deadlock (see 2171 * Documentation/filesystems/fuse.txt). 2172 * 2173 * Aborting requests under I/O goes as follows: 1: Separate out unlocked 2174 * requests, they should be finished off immediately. Locked requests will be 2175 * finished after unlock; see unlock_request(). 2: Finish off the unlocked 2176 * requests. It is possible that some request will finish before we can. This 2177 * is OK, the request will in that case be removed from the list before we touch 2178 * it. 2179 */ 2180 void fuse_abort_conn(struct fuse_conn *fc) 2181 { 2182 struct fuse_iqueue *fiq = &fc->iq; 2183 2184 spin_lock(&fc->lock); 2185 if (fc->connected) { 2186 struct fuse_dev *fud; 2187 struct fuse_req *req, *next; 2188 LIST_HEAD(to_end); 2189 unsigned int i; 2190 2191 /* Background queuing checks fc->connected under bg_lock */ 2192 spin_lock(&fc->bg_lock); 2193 fc->connected = 0; 2194 spin_unlock(&fc->bg_lock); 2195 2196 fuse_set_initialized(fc); 2197 list_for_each_entry(fud, &fc->devices, entry) { 2198 struct fuse_pqueue *fpq = &fud->pq; 2199 2200 spin_lock(&fpq->lock); 2201 fpq->connected = 0; 2202 list_for_each_entry_safe(req, next, &fpq->io, list) { 2203 req->out.h.error = -ECONNABORTED; 2204 spin_lock(&req->waitq.lock); 2205 set_bit(FR_ABORTED, &req->flags); 2206 if (!test_bit(FR_LOCKED, &req->flags)) { 2207 set_bit(FR_PRIVATE, &req->flags); 2208 __fuse_get_request(req); 2209 list_move(&req->list, &to_end); 2210 } 2211 spin_unlock(&req->waitq.lock); 2212 } 2213 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2214 list_splice_tail_init(&fpq->processing[i], 2215 &to_end); 2216 spin_unlock(&fpq->lock); 2217 } 2218 spin_lock(&fc->bg_lock); 2219 fc->blocked = 0; 2220 fc->max_background = UINT_MAX; 2221 flush_bg_queue(fc); 2222 spin_unlock(&fc->bg_lock); 2223 2224 spin_lock(&fiq->waitq.lock); 2225 fiq->connected = 0; 2226 list_for_each_entry(req, &fiq->pending, list) 2227 clear_bit(FR_PENDING, &req->flags); 2228 list_splice_tail_init(&fiq->pending, &to_end); 2229 while (forget_pending(fiq)) 2230 kfree(dequeue_forget(fiq, 1, NULL)); 2231 wake_up_all_locked(&fiq->waitq); 2232 spin_unlock(&fiq->waitq.lock); 2233 kill_fasync(&fiq->fasync, SIGIO, POLL_IN); 2234 end_polls(fc); 2235 wake_up_all(&fc->blocked_waitq); 2236 spin_unlock(&fc->lock); 2237 2238 end_requests(fc, &to_end); 2239 } else { 2240 spin_unlock(&fc->lock); 2241 } 2242 } 2243 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2244 2245 void fuse_wait_aborted(struct fuse_conn *fc) 2246 { 2247 /* matches implicit memory barrier in fuse_drop_waiting() */ 2248 smp_mb(); 2249 wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0); 2250 } 2251 2252 int fuse_dev_release(struct inode *inode, struct file *file) 2253 { 2254 struct fuse_dev *fud = fuse_get_dev(file); 2255 2256 if (fud) { 2257 struct fuse_conn *fc = fud->fc; 2258 struct fuse_pqueue *fpq = &fud->pq; 2259 LIST_HEAD(to_end); 2260 unsigned int i; 2261 2262 spin_lock(&fpq->lock); 2263 WARN_ON(!list_empty(&fpq->io)); 2264 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++) 2265 list_splice_init(&fpq->processing[i], &to_end); 2266 spin_unlock(&fpq->lock); 2267 2268 end_requests(fc, &to_end); 2269 2270 /* Are we the last open device? */ 2271 if (atomic_dec_and_test(&fc->dev_count)) { 2272 WARN_ON(fc->iq.fasync != NULL); 2273 fuse_abort_conn(fc); 2274 } 2275 fuse_dev_free(fud); 2276 } 2277 return 0; 2278 } 2279 EXPORT_SYMBOL_GPL(fuse_dev_release); 2280 2281 static int fuse_dev_fasync(int fd, struct file *file, int on) 2282 { 2283 struct fuse_dev *fud = fuse_get_dev(file); 2284 2285 if (!fud) 2286 return -EPERM; 2287 2288 /* No locking - fasync_helper does its own locking */ 2289 return fasync_helper(fd, file, on, &fud->fc->iq.fasync); 2290 } 2291 2292 static int fuse_device_clone(struct fuse_conn *fc, struct file *new) 2293 { 2294 struct fuse_dev *fud; 2295 2296 if (new->private_data) 2297 return -EINVAL; 2298 2299 fud = fuse_dev_alloc(fc); 2300 if (!fud) 2301 return -ENOMEM; 2302 2303 new->private_data = fud; 2304 atomic_inc(&fc->dev_count); 2305 2306 return 0; 2307 } 2308 2309 static long fuse_dev_ioctl(struct file *file, unsigned int cmd, 2310 unsigned long arg) 2311 { 2312 int err = -ENOTTY; 2313 2314 if (cmd == FUSE_DEV_IOC_CLONE) { 2315 int oldfd; 2316 2317 err = -EFAULT; 2318 if (!get_user(oldfd, (__u32 __user *) arg)) { 2319 struct file *old = fget(oldfd); 2320 2321 err = -EINVAL; 2322 if (old) { 2323 struct fuse_dev *fud = NULL; 2324 2325 /* 2326 * Check against file->f_op because CUSE 2327 * uses the same ioctl handler. 2328 */ 2329 if (old->f_op == file->f_op && 2330 old->f_cred->user_ns == file->f_cred->user_ns) 2331 fud = fuse_get_dev(old); 2332 2333 if (fud) { 2334 mutex_lock(&fuse_mutex); 2335 err = fuse_device_clone(fud->fc, file); 2336 mutex_unlock(&fuse_mutex); 2337 } 2338 fput(old); 2339 } 2340 } 2341 } 2342 return err; 2343 } 2344 2345 const struct file_operations fuse_dev_operations = { 2346 .owner = THIS_MODULE, 2347 .open = fuse_dev_open, 2348 .llseek = no_llseek, 2349 .read_iter = fuse_dev_read, 2350 .splice_read = fuse_dev_splice_read, 2351 .write_iter = fuse_dev_write, 2352 .splice_write = fuse_dev_splice_write, 2353 .poll = fuse_dev_poll, 2354 .release = fuse_dev_release, 2355 .fasync = fuse_dev_fasync, 2356 .unlocked_ioctl = fuse_dev_ioctl, 2357 .compat_ioctl = fuse_dev_ioctl, 2358 }; 2359 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2360 2361 static struct miscdevice fuse_miscdevice = { 2362 .minor = FUSE_MINOR, 2363 .name = "fuse", 2364 .fops = &fuse_dev_operations, 2365 }; 2366 2367 int __init fuse_dev_init(void) 2368 { 2369 int err = -ENOMEM; 2370 fuse_req_cachep = kmem_cache_create("fuse_request", 2371 sizeof(struct fuse_req), 2372 0, 0, NULL); 2373 if (!fuse_req_cachep) 2374 goto out; 2375 2376 err = misc_register(&fuse_miscdevice); 2377 if (err) 2378 goto out_cache_clean; 2379 2380 return 0; 2381 2382 out_cache_clean: 2383 kmem_cache_destroy(fuse_req_cachep); 2384 out: 2385 return err; 2386 } 2387 2388 void fuse_dev_cleanup(void) 2389 { 2390 misc_deregister(&fuse_miscdevice); 2391 kmem_cache_destroy(fuse_req_cachep); 2392 } 2393