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