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 static void fuse_request_send_nowait_locked(struct fuse_conn *fc, 515 struct fuse_req *req) 516 { 517 BUG_ON(!req->background); 518 fc->num_background++; 519 if (fc->num_background == fc->max_background) 520 fc->blocked = 1; 521 if (fc->num_background == fc->congestion_threshold && 522 fc->bdi_initialized) { 523 set_bdi_congested(&fc->bdi, BLK_RW_SYNC); 524 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC); 525 } 526 list_add_tail(&req->list, &fc->bg_queue); 527 flush_bg_queue(fc); 528 } 529 530 static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req) 531 { 532 spin_lock(&fc->lock); 533 if (fc->connected) { 534 fuse_request_send_nowait_locked(fc, req); 535 spin_unlock(&fc->lock); 536 } else { 537 req->out.h.error = -ENOTCONN; 538 request_end(fc, req); 539 } 540 } 541 542 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req) 543 { 544 req->isreply = 1; 545 fuse_request_send_nowait(fc, req); 546 } 547 EXPORT_SYMBOL_GPL(fuse_request_send_background); 548 549 static int fuse_request_send_notify_reply(struct fuse_conn *fc, 550 struct fuse_req *req, u64 unique) 551 { 552 int err = -ENODEV; 553 554 req->isreply = 0; 555 req->in.h.unique = unique; 556 spin_lock(&fc->lock); 557 if (fc->connected) { 558 queue_request(fc, req); 559 err = 0; 560 } 561 spin_unlock(&fc->lock); 562 563 return err; 564 } 565 566 /* 567 * Called under fc->lock 568 * 569 * fc->connected must have been checked previously 570 */ 571 void fuse_request_send_background_locked(struct fuse_conn *fc, 572 struct fuse_req *req) 573 { 574 req->isreply = 1; 575 fuse_request_send_nowait_locked(fc, req); 576 } 577 578 void fuse_force_forget(struct file *file, u64 nodeid) 579 { 580 struct inode *inode = file_inode(file); 581 struct fuse_conn *fc = get_fuse_conn(inode); 582 struct fuse_req *req; 583 struct fuse_forget_in inarg; 584 585 memset(&inarg, 0, sizeof(inarg)); 586 inarg.nlookup = 1; 587 req = fuse_get_req_nofail_nopages(fc, file); 588 req->in.h.opcode = FUSE_FORGET; 589 req->in.h.nodeid = nodeid; 590 req->in.numargs = 1; 591 req->in.args[0].size = sizeof(inarg); 592 req->in.args[0].value = &inarg; 593 req->isreply = 0; 594 __fuse_request_send(fc, req); 595 /* ignore errors */ 596 fuse_put_request(fc, req); 597 } 598 599 /* 600 * Lock the request. Up to the next unlock_request() there mustn't be 601 * anything that could cause a page-fault. If the request was already 602 * aborted bail out. 603 */ 604 static int lock_request(struct fuse_conn *fc, struct fuse_req *req) 605 { 606 int err = 0; 607 if (req) { 608 spin_lock(&fc->lock); 609 if (req->aborted) 610 err = -ENOENT; 611 else 612 req->locked = 1; 613 spin_unlock(&fc->lock); 614 } 615 return err; 616 } 617 618 /* 619 * Unlock request. If it was aborted during being locked, the 620 * requester thread is currently waiting for it to be unlocked, so 621 * wake it up. 622 */ 623 static void unlock_request(struct fuse_conn *fc, struct fuse_req *req) 624 { 625 if (req) { 626 spin_lock(&fc->lock); 627 req->locked = 0; 628 if (req->aborted) 629 wake_up(&req->waitq); 630 spin_unlock(&fc->lock); 631 } 632 } 633 634 struct fuse_copy_state { 635 struct fuse_conn *fc; 636 int write; 637 struct fuse_req *req; 638 const struct iovec *iov; 639 struct pipe_buffer *pipebufs; 640 struct pipe_buffer *currbuf; 641 struct pipe_inode_info *pipe; 642 unsigned long nr_segs; 643 unsigned long seglen; 644 unsigned long addr; 645 struct page *pg; 646 void *mapaddr; 647 void *buf; 648 unsigned len; 649 unsigned move_pages:1; 650 }; 651 652 static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc, 653 int write, 654 const struct iovec *iov, unsigned long nr_segs) 655 { 656 memset(cs, 0, sizeof(*cs)); 657 cs->fc = fc; 658 cs->write = write; 659 cs->iov = iov; 660 cs->nr_segs = nr_segs; 661 } 662 663 /* Unmap and put previous page of userspace buffer */ 664 static void fuse_copy_finish(struct fuse_copy_state *cs) 665 { 666 if (cs->currbuf) { 667 struct pipe_buffer *buf = cs->currbuf; 668 669 if (!cs->write) { 670 buf->ops->unmap(cs->pipe, buf, cs->mapaddr); 671 } else { 672 kunmap(buf->page); 673 buf->len = PAGE_SIZE - cs->len; 674 } 675 cs->currbuf = NULL; 676 cs->mapaddr = NULL; 677 } else if (cs->mapaddr) { 678 kunmap(cs->pg); 679 if (cs->write) { 680 flush_dcache_page(cs->pg); 681 set_page_dirty_lock(cs->pg); 682 } 683 put_page(cs->pg); 684 cs->mapaddr = NULL; 685 } 686 } 687 688 /* 689 * Get another pagefull of userspace buffer, and map it to kernel 690 * address space, and lock request 691 */ 692 static int fuse_copy_fill(struct fuse_copy_state *cs) 693 { 694 unsigned long offset; 695 int err; 696 697 unlock_request(cs->fc, cs->req); 698 fuse_copy_finish(cs); 699 if (cs->pipebufs) { 700 struct pipe_buffer *buf = cs->pipebufs; 701 702 if (!cs->write) { 703 err = buf->ops->confirm(cs->pipe, buf); 704 if (err) 705 return err; 706 707 BUG_ON(!cs->nr_segs); 708 cs->currbuf = buf; 709 cs->mapaddr = buf->ops->map(cs->pipe, buf, 0); 710 cs->len = buf->len; 711 cs->buf = cs->mapaddr + buf->offset; 712 cs->pipebufs++; 713 cs->nr_segs--; 714 } else { 715 struct page *page; 716 717 if (cs->nr_segs == cs->pipe->buffers) 718 return -EIO; 719 720 page = alloc_page(GFP_HIGHUSER); 721 if (!page) 722 return -ENOMEM; 723 724 buf->page = page; 725 buf->offset = 0; 726 buf->len = 0; 727 728 cs->currbuf = buf; 729 cs->mapaddr = kmap(page); 730 cs->buf = cs->mapaddr; 731 cs->len = PAGE_SIZE; 732 cs->pipebufs++; 733 cs->nr_segs++; 734 } 735 } else { 736 if (!cs->seglen) { 737 BUG_ON(!cs->nr_segs); 738 cs->seglen = cs->iov[0].iov_len; 739 cs->addr = (unsigned long) cs->iov[0].iov_base; 740 cs->iov++; 741 cs->nr_segs--; 742 } 743 err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg); 744 if (err < 0) 745 return err; 746 BUG_ON(err != 1); 747 offset = cs->addr % PAGE_SIZE; 748 cs->mapaddr = kmap(cs->pg); 749 cs->buf = cs->mapaddr + offset; 750 cs->len = min(PAGE_SIZE - offset, cs->seglen); 751 cs->seglen -= cs->len; 752 cs->addr += cs->len; 753 } 754 755 return lock_request(cs->fc, cs->req); 756 } 757 758 /* Do as much copy to/from userspace buffer as we can */ 759 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size) 760 { 761 unsigned ncpy = min(*size, cs->len); 762 if (val) { 763 if (cs->write) 764 memcpy(cs->buf, *val, ncpy); 765 else 766 memcpy(*val, cs->buf, ncpy); 767 *val += ncpy; 768 } 769 *size -= ncpy; 770 cs->len -= ncpy; 771 cs->buf += ncpy; 772 return ncpy; 773 } 774 775 static int fuse_check_page(struct page *page) 776 { 777 if (page_mapcount(page) || 778 page->mapping != NULL || 779 page_count(page) != 1 || 780 (page->flags & PAGE_FLAGS_CHECK_AT_PREP & 781 ~(1 << PG_locked | 782 1 << PG_referenced | 783 1 << PG_uptodate | 784 1 << PG_lru | 785 1 << PG_active | 786 1 << PG_reclaim))) { 787 printk(KERN_WARNING "fuse: trying to steal weird page\n"); 788 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); 789 return 1; 790 } 791 return 0; 792 } 793 794 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep) 795 { 796 int err; 797 struct page *oldpage = *pagep; 798 struct page *newpage; 799 struct pipe_buffer *buf = cs->pipebufs; 800 801 unlock_request(cs->fc, cs->req); 802 fuse_copy_finish(cs); 803 804 err = buf->ops->confirm(cs->pipe, buf); 805 if (err) 806 return err; 807 808 BUG_ON(!cs->nr_segs); 809 cs->currbuf = buf; 810 cs->len = buf->len; 811 cs->pipebufs++; 812 cs->nr_segs--; 813 814 if (cs->len != PAGE_SIZE) 815 goto out_fallback; 816 817 if (buf->ops->steal(cs->pipe, buf) != 0) 818 goto out_fallback; 819 820 newpage = buf->page; 821 822 if (WARN_ON(!PageUptodate(newpage))) 823 return -EIO; 824 825 ClearPageMappedToDisk(newpage); 826 827 if (fuse_check_page(newpage) != 0) 828 goto out_fallback_unlock; 829 830 /* 831 * This is a new and locked page, it shouldn't be mapped or 832 * have any special flags on it 833 */ 834 if (WARN_ON(page_mapped(oldpage))) 835 goto out_fallback_unlock; 836 if (WARN_ON(page_has_private(oldpage))) 837 goto out_fallback_unlock; 838 if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage))) 839 goto out_fallback_unlock; 840 if (WARN_ON(PageMlocked(oldpage))) 841 goto out_fallback_unlock; 842 843 err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL); 844 if (err) { 845 unlock_page(newpage); 846 return err; 847 } 848 849 page_cache_get(newpage); 850 851 if (!(buf->flags & PIPE_BUF_FLAG_LRU)) 852 lru_cache_add_file(newpage); 853 854 err = 0; 855 spin_lock(&cs->fc->lock); 856 if (cs->req->aborted) 857 err = -ENOENT; 858 else 859 *pagep = newpage; 860 spin_unlock(&cs->fc->lock); 861 862 if (err) { 863 unlock_page(newpage); 864 page_cache_release(newpage); 865 return err; 866 } 867 868 unlock_page(oldpage); 869 page_cache_release(oldpage); 870 cs->len = 0; 871 872 return 0; 873 874 out_fallback_unlock: 875 unlock_page(newpage); 876 out_fallback: 877 cs->mapaddr = buf->ops->map(cs->pipe, buf, 1); 878 cs->buf = cs->mapaddr + buf->offset; 879 880 err = lock_request(cs->fc, cs->req); 881 if (err) 882 return err; 883 884 return 1; 885 } 886 887 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page, 888 unsigned offset, unsigned count) 889 { 890 struct pipe_buffer *buf; 891 892 if (cs->nr_segs == cs->pipe->buffers) 893 return -EIO; 894 895 unlock_request(cs->fc, cs->req); 896 fuse_copy_finish(cs); 897 898 buf = cs->pipebufs; 899 page_cache_get(page); 900 buf->page = page; 901 buf->offset = offset; 902 buf->len = count; 903 904 cs->pipebufs++; 905 cs->nr_segs++; 906 cs->len = 0; 907 908 return 0; 909 } 910 911 /* 912 * Copy a page in the request to/from the userspace buffer. Must be 913 * done atomically 914 */ 915 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep, 916 unsigned offset, unsigned count, int zeroing) 917 { 918 int err; 919 struct page *page = *pagep; 920 921 if (page && zeroing && count < PAGE_SIZE) 922 clear_highpage(page); 923 924 while (count) { 925 if (cs->write && cs->pipebufs && page) { 926 return fuse_ref_page(cs, page, offset, count); 927 } else if (!cs->len) { 928 if (cs->move_pages && page && 929 offset == 0 && count == PAGE_SIZE) { 930 err = fuse_try_move_page(cs, pagep); 931 if (err <= 0) 932 return err; 933 } else { 934 err = fuse_copy_fill(cs); 935 if (err) 936 return err; 937 } 938 } 939 if (page) { 940 void *mapaddr = kmap_atomic(page); 941 void *buf = mapaddr + offset; 942 offset += fuse_copy_do(cs, &buf, &count); 943 kunmap_atomic(mapaddr); 944 } else 945 offset += fuse_copy_do(cs, NULL, &count); 946 } 947 if (page && !cs->write) 948 flush_dcache_page(page); 949 return 0; 950 } 951 952 /* Copy pages in the request to/from userspace buffer */ 953 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes, 954 int zeroing) 955 { 956 unsigned i; 957 struct fuse_req *req = cs->req; 958 959 for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) { 960 int err; 961 unsigned offset = req->page_descs[i].offset; 962 unsigned count = min(nbytes, req->page_descs[i].length); 963 964 err = fuse_copy_page(cs, &req->pages[i], offset, count, 965 zeroing); 966 if (err) 967 return err; 968 969 nbytes -= count; 970 } 971 return 0; 972 } 973 974 /* Copy a single argument in the request to/from userspace buffer */ 975 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size) 976 { 977 while (size) { 978 if (!cs->len) { 979 int err = fuse_copy_fill(cs); 980 if (err) 981 return err; 982 } 983 fuse_copy_do(cs, &val, &size); 984 } 985 return 0; 986 } 987 988 /* Copy request arguments to/from userspace buffer */ 989 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs, 990 unsigned argpages, struct fuse_arg *args, 991 int zeroing) 992 { 993 int err = 0; 994 unsigned i; 995 996 for (i = 0; !err && i < numargs; i++) { 997 struct fuse_arg *arg = &args[i]; 998 if (i == numargs - 1 && argpages) 999 err = fuse_copy_pages(cs, arg->size, zeroing); 1000 else 1001 err = fuse_copy_one(cs, arg->value, arg->size); 1002 } 1003 return err; 1004 } 1005 1006 static int forget_pending(struct fuse_conn *fc) 1007 { 1008 return fc->forget_list_head.next != NULL; 1009 } 1010 1011 static int request_pending(struct fuse_conn *fc) 1012 { 1013 return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) || 1014 forget_pending(fc); 1015 } 1016 1017 /* Wait until a request is available on the pending list */ 1018 static void request_wait(struct fuse_conn *fc) 1019 __releases(fc->lock) 1020 __acquires(fc->lock) 1021 { 1022 DECLARE_WAITQUEUE(wait, current); 1023 1024 add_wait_queue_exclusive(&fc->waitq, &wait); 1025 while (fc->connected && !request_pending(fc)) { 1026 set_current_state(TASK_INTERRUPTIBLE); 1027 if (signal_pending(current)) 1028 break; 1029 1030 spin_unlock(&fc->lock); 1031 schedule(); 1032 spin_lock(&fc->lock); 1033 } 1034 set_current_state(TASK_RUNNING); 1035 remove_wait_queue(&fc->waitq, &wait); 1036 } 1037 1038 /* 1039 * Transfer an interrupt request to userspace 1040 * 1041 * Unlike other requests this is assembled on demand, without a need 1042 * to allocate a separate fuse_req structure. 1043 * 1044 * Called with fc->lock held, releases it 1045 */ 1046 static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs, 1047 size_t nbytes, struct fuse_req *req) 1048 __releases(fc->lock) 1049 { 1050 struct fuse_in_header ih; 1051 struct fuse_interrupt_in arg; 1052 unsigned reqsize = sizeof(ih) + sizeof(arg); 1053 int err; 1054 1055 list_del_init(&req->intr_entry); 1056 req->intr_unique = fuse_get_unique(fc); 1057 memset(&ih, 0, sizeof(ih)); 1058 memset(&arg, 0, sizeof(arg)); 1059 ih.len = reqsize; 1060 ih.opcode = FUSE_INTERRUPT; 1061 ih.unique = req->intr_unique; 1062 arg.unique = req->in.h.unique; 1063 1064 spin_unlock(&fc->lock); 1065 if (nbytes < reqsize) 1066 return -EINVAL; 1067 1068 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1069 if (!err) 1070 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1071 fuse_copy_finish(cs); 1072 1073 return err ? err : reqsize; 1074 } 1075 1076 static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc, 1077 unsigned max, 1078 unsigned *countp) 1079 { 1080 struct fuse_forget_link *head = fc->forget_list_head.next; 1081 struct fuse_forget_link **newhead = &head; 1082 unsigned count; 1083 1084 for (count = 0; *newhead != NULL && count < max; count++) 1085 newhead = &(*newhead)->next; 1086 1087 fc->forget_list_head.next = *newhead; 1088 *newhead = NULL; 1089 if (fc->forget_list_head.next == NULL) 1090 fc->forget_list_tail = &fc->forget_list_head; 1091 1092 if (countp != NULL) 1093 *countp = count; 1094 1095 return head; 1096 } 1097 1098 static int fuse_read_single_forget(struct fuse_conn *fc, 1099 struct fuse_copy_state *cs, 1100 size_t nbytes) 1101 __releases(fc->lock) 1102 { 1103 int err; 1104 struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL); 1105 struct fuse_forget_in arg = { 1106 .nlookup = forget->forget_one.nlookup, 1107 }; 1108 struct fuse_in_header ih = { 1109 .opcode = FUSE_FORGET, 1110 .nodeid = forget->forget_one.nodeid, 1111 .unique = fuse_get_unique(fc), 1112 .len = sizeof(ih) + sizeof(arg), 1113 }; 1114 1115 spin_unlock(&fc->lock); 1116 kfree(forget); 1117 if (nbytes < ih.len) 1118 return -EINVAL; 1119 1120 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1121 if (!err) 1122 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1123 fuse_copy_finish(cs); 1124 1125 if (err) 1126 return err; 1127 1128 return ih.len; 1129 } 1130 1131 static int fuse_read_batch_forget(struct fuse_conn *fc, 1132 struct fuse_copy_state *cs, size_t nbytes) 1133 __releases(fc->lock) 1134 { 1135 int err; 1136 unsigned max_forgets; 1137 unsigned count; 1138 struct fuse_forget_link *head; 1139 struct fuse_batch_forget_in arg = { .count = 0 }; 1140 struct fuse_in_header ih = { 1141 .opcode = FUSE_BATCH_FORGET, 1142 .unique = fuse_get_unique(fc), 1143 .len = sizeof(ih) + sizeof(arg), 1144 }; 1145 1146 if (nbytes < ih.len) { 1147 spin_unlock(&fc->lock); 1148 return -EINVAL; 1149 } 1150 1151 max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one); 1152 head = dequeue_forget(fc, max_forgets, &count); 1153 spin_unlock(&fc->lock); 1154 1155 arg.count = count; 1156 ih.len += count * sizeof(struct fuse_forget_one); 1157 err = fuse_copy_one(cs, &ih, sizeof(ih)); 1158 if (!err) 1159 err = fuse_copy_one(cs, &arg, sizeof(arg)); 1160 1161 while (head) { 1162 struct fuse_forget_link *forget = head; 1163 1164 if (!err) { 1165 err = fuse_copy_one(cs, &forget->forget_one, 1166 sizeof(forget->forget_one)); 1167 } 1168 head = forget->next; 1169 kfree(forget); 1170 } 1171 1172 fuse_copy_finish(cs); 1173 1174 if (err) 1175 return err; 1176 1177 return ih.len; 1178 } 1179 1180 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs, 1181 size_t nbytes) 1182 __releases(fc->lock) 1183 { 1184 if (fc->minor < 16 || fc->forget_list_head.next->next == NULL) 1185 return fuse_read_single_forget(fc, cs, nbytes); 1186 else 1187 return fuse_read_batch_forget(fc, cs, nbytes); 1188 } 1189 1190 /* 1191 * Read a single request into the userspace filesystem's buffer. This 1192 * function waits until a request is available, then removes it from 1193 * the pending list and copies request data to userspace buffer. If 1194 * no reply is needed (FORGET) or request has been aborted or there 1195 * was an error during the copying then it's finished by calling 1196 * request_end(). Otherwise add it to the processing list, and set 1197 * the 'sent' flag. 1198 */ 1199 static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file, 1200 struct fuse_copy_state *cs, size_t nbytes) 1201 { 1202 int err; 1203 struct fuse_req *req; 1204 struct fuse_in *in; 1205 unsigned reqsize; 1206 1207 restart: 1208 spin_lock(&fc->lock); 1209 err = -EAGAIN; 1210 if ((file->f_flags & O_NONBLOCK) && fc->connected && 1211 !request_pending(fc)) 1212 goto err_unlock; 1213 1214 request_wait(fc); 1215 err = -ENODEV; 1216 if (!fc->connected) 1217 goto err_unlock; 1218 err = -ERESTARTSYS; 1219 if (!request_pending(fc)) 1220 goto err_unlock; 1221 1222 if (!list_empty(&fc->interrupts)) { 1223 req = list_entry(fc->interrupts.next, struct fuse_req, 1224 intr_entry); 1225 return fuse_read_interrupt(fc, cs, nbytes, req); 1226 } 1227 1228 if (forget_pending(fc)) { 1229 if (list_empty(&fc->pending) || fc->forget_batch-- > 0) 1230 return fuse_read_forget(fc, cs, nbytes); 1231 1232 if (fc->forget_batch <= -8) 1233 fc->forget_batch = 16; 1234 } 1235 1236 req = list_entry(fc->pending.next, struct fuse_req, list); 1237 req->state = FUSE_REQ_READING; 1238 list_move(&req->list, &fc->io); 1239 1240 in = &req->in; 1241 reqsize = in->h.len; 1242 /* If request is too large, reply with an error and restart the read */ 1243 if (nbytes < reqsize) { 1244 req->out.h.error = -EIO; 1245 /* SETXATTR is special, since it may contain too large data */ 1246 if (in->h.opcode == FUSE_SETXATTR) 1247 req->out.h.error = -E2BIG; 1248 request_end(fc, req); 1249 goto restart; 1250 } 1251 spin_unlock(&fc->lock); 1252 cs->req = req; 1253 err = fuse_copy_one(cs, &in->h, sizeof(in->h)); 1254 if (!err) 1255 err = fuse_copy_args(cs, in->numargs, in->argpages, 1256 (struct fuse_arg *) in->args, 0); 1257 fuse_copy_finish(cs); 1258 spin_lock(&fc->lock); 1259 req->locked = 0; 1260 if (req->aborted) { 1261 request_end(fc, req); 1262 return -ENODEV; 1263 } 1264 if (err) { 1265 req->out.h.error = -EIO; 1266 request_end(fc, req); 1267 return err; 1268 } 1269 if (!req->isreply) 1270 request_end(fc, req); 1271 else { 1272 req->state = FUSE_REQ_SENT; 1273 list_move_tail(&req->list, &fc->processing); 1274 if (req->interrupted) 1275 queue_interrupt(fc, req); 1276 spin_unlock(&fc->lock); 1277 } 1278 return reqsize; 1279 1280 err_unlock: 1281 spin_unlock(&fc->lock); 1282 return err; 1283 } 1284 1285 static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov, 1286 unsigned long nr_segs, loff_t pos) 1287 { 1288 struct fuse_copy_state cs; 1289 struct file *file = iocb->ki_filp; 1290 struct fuse_conn *fc = fuse_get_conn(file); 1291 if (!fc) 1292 return -EPERM; 1293 1294 fuse_copy_init(&cs, fc, 1, iov, nr_segs); 1295 1296 return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs)); 1297 } 1298 1299 static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe, 1300 struct pipe_buffer *buf) 1301 { 1302 return 1; 1303 } 1304 1305 static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = { 1306 .can_merge = 0, 1307 .map = generic_pipe_buf_map, 1308 .unmap = generic_pipe_buf_unmap, 1309 .confirm = generic_pipe_buf_confirm, 1310 .release = generic_pipe_buf_release, 1311 .steal = fuse_dev_pipe_buf_steal, 1312 .get = generic_pipe_buf_get, 1313 }; 1314 1315 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos, 1316 struct pipe_inode_info *pipe, 1317 size_t len, unsigned int flags) 1318 { 1319 int ret; 1320 int page_nr = 0; 1321 int do_wakeup = 0; 1322 struct pipe_buffer *bufs; 1323 struct fuse_copy_state cs; 1324 struct fuse_conn *fc = fuse_get_conn(in); 1325 if (!fc) 1326 return -EPERM; 1327 1328 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1329 if (!bufs) 1330 return -ENOMEM; 1331 1332 fuse_copy_init(&cs, fc, 1, NULL, 0); 1333 cs.pipebufs = bufs; 1334 cs.pipe = pipe; 1335 ret = fuse_dev_do_read(fc, in, &cs, len); 1336 if (ret < 0) 1337 goto out; 1338 1339 ret = 0; 1340 pipe_lock(pipe); 1341 1342 if (!pipe->readers) { 1343 send_sig(SIGPIPE, current, 0); 1344 if (!ret) 1345 ret = -EPIPE; 1346 goto out_unlock; 1347 } 1348 1349 if (pipe->nrbufs + cs.nr_segs > pipe->buffers) { 1350 ret = -EIO; 1351 goto out_unlock; 1352 } 1353 1354 while (page_nr < cs.nr_segs) { 1355 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1); 1356 struct pipe_buffer *buf = pipe->bufs + newbuf; 1357 1358 buf->page = bufs[page_nr].page; 1359 buf->offset = bufs[page_nr].offset; 1360 buf->len = bufs[page_nr].len; 1361 buf->ops = &fuse_dev_pipe_buf_ops; 1362 1363 pipe->nrbufs++; 1364 page_nr++; 1365 ret += buf->len; 1366 1367 if (pipe->files) 1368 do_wakeup = 1; 1369 } 1370 1371 out_unlock: 1372 pipe_unlock(pipe); 1373 1374 if (do_wakeup) { 1375 smp_mb(); 1376 if (waitqueue_active(&pipe->wait)) 1377 wake_up_interruptible(&pipe->wait); 1378 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); 1379 } 1380 1381 out: 1382 for (; page_nr < cs.nr_segs; page_nr++) 1383 page_cache_release(bufs[page_nr].page); 1384 1385 kfree(bufs); 1386 return ret; 1387 } 1388 1389 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size, 1390 struct fuse_copy_state *cs) 1391 { 1392 struct fuse_notify_poll_wakeup_out outarg; 1393 int err = -EINVAL; 1394 1395 if (size != sizeof(outarg)) 1396 goto err; 1397 1398 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1399 if (err) 1400 goto err; 1401 1402 fuse_copy_finish(cs); 1403 return fuse_notify_poll_wakeup(fc, &outarg); 1404 1405 err: 1406 fuse_copy_finish(cs); 1407 return err; 1408 } 1409 1410 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size, 1411 struct fuse_copy_state *cs) 1412 { 1413 struct fuse_notify_inval_inode_out outarg; 1414 int err = -EINVAL; 1415 1416 if (size != sizeof(outarg)) 1417 goto err; 1418 1419 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1420 if (err) 1421 goto err; 1422 fuse_copy_finish(cs); 1423 1424 down_read(&fc->killsb); 1425 err = -ENOENT; 1426 if (fc->sb) { 1427 err = fuse_reverse_inval_inode(fc->sb, outarg.ino, 1428 outarg.off, outarg.len); 1429 } 1430 up_read(&fc->killsb); 1431 return err; 1432 1433 err: 1434 fuse_copy_finish(cs); 1435 return err; 1436 } 1437 1438 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size, 1439 struct fuse_copy_state *cs) 1440 { 1441 struct fuse_notify_inval_entry_out outarg; 1442 int err = -ENOMEM; 1443 char *buf; 1444 struct qstr name; 1445 1446 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1447 if (!buf) 1448 goto err; 1449 1450 err = -EINVAL; 1451 if (size < sizeof(outarg)) 1452 goto err; 1453 1454 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1455 if (err) 1456 goto err; 1457 1458 err = -ENAMETOOLONG; 1459 if (outarg.namelen > FUSE_NAME_MAX) 1460 goto err; 1461 1462 err = -EINVAL; 1463 if (size != sizeof(outarg) + outarg.namelen + 1) 1464 goto err; 1465 1466 name.name = buf; 1467 name.len = outarg.namelen; 1468 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1469 if (err) 1470 goto err; 1471 fuse_copy_finish(cs); 1472 buf[outarg.namelen] = 0; 1473 name.hash = full_name_hash(name.name, name.len); 1474 1475 down_read(&fc->killsb); 1476 err = -ENOENT; 1477 if (fc->sb) 1478 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name); 1479 up_read(&fc->killsb); 1480 kfree(buf); 1481 return err; 1482 1483 err: 1484 kfree(buf); 1485 fuse_copy_finish(cs); 1486 return err; 1487 } 1488 1489 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size, 1490 struct fuse_copy_state *cs) 1491 { 1492 struct fuse_notify_delete_out outarg; 1493 int err = -ENOMEM; 1494 char *buf; 1495 struct qstr name; 1496 1497 buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL); 1498 if (!buf) 1499 goto err; 1500 1501 err = -EINVAL; 1502 if (size < sizeof(outarg)) 1503 goto err; 1504 1505 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1506 if (err) 1507 goto err; 1508 1509 err = -ENAMETOOLONG; 1510 if (outarg.namelen > FUSE_NAME_MAX) 1511 goto err; 1512 1513 err = -EINVAL; 1514 if (size != sizeof(outarg) + outarg.namelen + 1) 1515 goto err; 1516 1517 name.name = buf; 1518 name.len = outarg.namelen; 1519 err = fuse_copy_one(cs, buf, outarg.namelen + 1); 1520 if (err) 1521 goto err; 1522 fuse_copy_finish(cs); 1523 buf[outarg.namelen] = 0; 1524 name.hash = full_name_hash(name.name, name.len); 1525 1526 down_read(&fc->killsb); 1527 err = -ENOENT; 1528 if (fc->sb) 1529 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 1530 outarg.child, &name); 1531 up_read(&fc->killsb); 1532 kfree(buf); 1533 return err; 1534 1535 err: 1536 kfree(buf); 1537 fuse_copy_finish(cs); 1538 return err; 1539 } 1540 1541 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size, 1542 struct fuse_copy_state *cs) 1543 { 1544 struct fuse_notify_store_out outarg; 1545 struct inode *inode; 1546 struct address_space *mapping; 1547 u64 nodeid; 1548 int err; 1549 pgoff_t index; 1550 unsigned int offset; 1551 unsigned int num; 1552 loff_t file_size; 1553 loff_t end; 1554 1555 err = -EINVAL; 1556 if (size < sizeof(outarg)) 1557 goto out_finish; 1558 1559 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1560 if (err) 1561 goto out_finish; 1562 1563 err = -EINVAL; 1564 if (size - sizeof(outarg) != outarg.size) 1565 goto out_finish; 1566 1567 nodeid = outarg.nodeid; 1568 1569 down_read(&fc->killsb); 1570 1571 err = -ENOENT; 1572 if (!fc->sb) 1573 goto out_up_killsb; 1574 1575 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1576 if (!inode) 1577 goto out_up_killsb; 1578 1579 mapping = inode->i_mapping; 1580 index = outarg.offset >> PAGE_CACHE_SHIFT; 1581 offset = outarg.offset & ~PAGE_CACHE_MASK; 1582 file_size = i_size_read(inode); 1583 end = outarg.offset + outarg.size; 1584 if (end > file_size) { 1585 file_size = end; 1586 fuse_write_update_size(inode, file_size); 1587 } 1588 1589 num = outarg.size; 1590 while (num) { 1591 struct page *page; 1592 unsigned int this_num; 1593 1594 err = -ENOMEM; 1595 page = find_or_create_page(mapping, index, 1596 mapping_gfp_mask(mapping)); 1597 if (!page) 1598 goto out_iput; 1599 1600 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset); 1601 err = fuse_copy_page(cs, &page, offset, this_num, 0); 1602 if (!err && offset == 0 && (num != 0 || file_size == end)) 1603 SetPageUptodate(page); 1604 unlock_page(page); 1605 page_cache_release(page); 1606 1607 if (err) 1608 goto out_iput; 1609 1610 num -= this_num; 1611 offset = 0; 1612 index++; 1613 } 1614 1615 err = 0; 1616 1617 out_iput: 1618 iput(inode); 1619 out_up_killsb: 1620 up_read(&fc->killsb); 1621 out_finish: 1622 fuse_copy_finish(cs); 1623 return err; 1624 } 1625 1626 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req) 1627 { 1628 release_pages(req->pages, req->num_pages, 0); 1629 } 1630 1631 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode, 1632 struct fuse_notify_retrieve_out *outarg) 1633 { 1634 int err; 1635 struct address_space *mapping = inode->i_mapping; 1636 struct fuse_req *req; 1637 pgoff_t index; 1638 loff_t file_size; 1639 unsigned int num; 1640 unsigned int offset; 1641 size_t total_len = 0; 1642 int num_pages; 1643 1644 offset = outarg->offset & ~PAGE_CACHE_MASK; 1645 file_size = i_size_read(inode); 1646 1647 num = outarg->size; 1648 if (outarg->offset > file_size) 1649 num = 0; 1650 else if (outarg->offset + num > file_size) 1651 num = file_size - outarg->offset; 1652 1653 num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; 1654 num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ); 1655 1656 req = fuse_get_req(fc, num_pages); 1657 if (IS_ERR(req)) 1658 return PTR_ERR(req); 1659 1660 req->in.h.opcode = FUSE_NOTIFY_REPLY; 1661 req->in.h.nodeid = outarg->nodeid; 1662 req->in.numargs = 2; 1663 req->in.argpages = 1; 1664 req->page_descs[0].offset = offset; 1665 req->end = fuse_retrieve_end; 1666 1667 index = outarg->offset >> PAGE_CACHE_SHIFT; 1668 1669 while (num && req->num_pages < num_pages) { 1670 struct page *page; 1671 unsigned int this_num; 1672 1673 page = find_get_page(mapping, index); 1674 if (!page) 1675 break; 1676 1677 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset); 1678 req->pages[req->num_pages] = page; 1679 req->page_descs[req->num_pages].length = this_num; 1680 req->num_pages++; 1681 1682 offset = 0; 1683 num -= this_num; 1684 total_len += this_num; 1685 index++; 1686 } 1687 req->misc.retrieve_in.offset = outarg->offset; 1688 req->misc.retrieve_in.size = total_len; 1689 req->in.args[0].size = sizeof(req->misc.retrieve_in); 1690 req->in.args[0].value = &req->misc.retrieve_in; 1691 req->in.args[1].size = total_len; 1692 1693 err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique); 1694 if (err) 1695 fuse_retrieve_end(fc, req); 1696 1697 return err; 1698 } 1699 1700 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size, 1701 struct fuse_copy_state *cs) 1702 { 1703 struct fuse_notify_retrieve_out outarg; 1704 struct inode *inode; 1705 int err; 1706 1707 err = -EINVAL; 1708 if (size != sizeof(outarg)) 1709 goto copy_finish; 1710 1711 err = fuse_copy_one(cs, &outarg, sizeof(outarg)); 1712 if (err) 1713 goto copy_finish; 1714 1715 fuse_copy_finish(cs); 1716 1717 down_read(&fc->killsb); 1718 err = -ENOENT; 1719 if (fc->sb) { 1720 u64 nodeid = outarg.nodeid; 1721 1722 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid); 1723 if (inode) { 1724 err = fuse_retrieve(fc, inode, &outarg); 1725 iput(inode); 1726 } 1727 } 1728 up_read(&fc->killsb); 1729 1730 return err; 1731 1732 copy_finish: 1733 fuse_copy_finish(cs); 1734 return err; 1735 } 1736 1737 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code, 1738 unsigned int size, struct fuse_copy_state *cs) 1739 { 1740 switch (code) { 1741 case FUSE_NOTIFY_POLL: 1742 return fuse_notify_poll(fc, size, cs); 1743 1744 case FUSE_NOTIFY_INVAL_INODE: 1745 return fuse_notify_inval_inode(fc, size, cs); 1746 1747 case FUSE_NOTIFY_INVAL_ENTRY: 1748 return fuse_notify_inval_entry(fc, size, cs); 1749 1750 case FUSE_NOTIFY_STORE: 1751 return fuse_notify_store(fc, size, cs); 1752 1753 case FUSE_NOTIFY_RETRIEVE: 1754 return fuse_notify_retrieve(fc, size, cs); 1755 1756 case FUSE_NOTIFY_DELETE: 1757 return fuse_notify_delete(fc, size, cs); 1758 1759 default: 1760 fuse_copy_finish(cs); 1761 return -EINVAL; 1762 } 1763 } 1764 1765 /* Look up request on processing list by unique ID */ 1766 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique) 1767 { 1768 struct list_head *entry; 1769 1770 list_for_each(entry, &fc->processing) { 1771 struct fuse_req *req; 1772 req = list_entry(entry, struct fuse_req, list); 1773 if (req->in.h.unique == unique || req->intr_unique == unique) 1774 return req; 1775 } 1776 return NULL; 1777 } 1778 1779 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out, 1780 unsigned nbytes) 1781 { 1782 unsigned reqsize = sizeof(struct fuse_out_header); 1783 1784 if (out->h.error) 1785 return nbytes != reqsize ? -EINVAL : 0; 1786 1787 reqsize += len_args(out->numargs, out->args); 1788 1789 if (reqsize < nbytes || (reqsize > nbytes && !out->argvar)) 1790 return -EINVAL; 1791 else if (reqsize > nbytes) { 1792 struct fuse_arg *lastarg = &out->args[out->numargs-1]; 1793 unsigned diffsize = reqsize - nbytes; 1794 if (diffsize > lastarg->size) 1795 return -EINVAL; 1796 lastarg->size -= diffsize; 1797 } 1798 return fuse_copy_args(cs, out->numargs, out->argpages, out->args, 1799 out->page_zeroing); 1800 } 1801 1802 /* 1803 * Write a single reply to a request. First the header is copied from 1804 * the write buffer. The request is then searched on the processing 1805 * list by the unique ID found in the header. If found, then remove 1806 * it from the list and copy the rest of the buffer to the request. 1807 * The request is finished by calling request_end() 1808 */ 1809 static ssize_t fuse_dev_do_write(struct fuse_conn *fc, 1810 struct fuse_copy_state *cs, size_t nbytes) 1811 { 1812 int err; 1813 struct fuse_req *req; 1814 struct fuse_out_header oh; 1815 1816 if (nbytes < sizeof(struct fuse_out_header)) 1817 return -EINVAL; 1818 1819 err = fuse_copy_one(cs, &oh, sizeof(oh)); 1820 if (err) 1821 goto err_finish; 1822 1823 err = -EINVAL; 1824 if (oh.len != nbytes) 1825 goto err_finish; 1826 1827 /* 1828 * Zero oh.unique indicates unsolicited notification message 1829 * and error contains notification code. 1830 */ 1831 if (!oh.unique) { 1832 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs); 1833 return err ? err : nbytes; 1834 } 1835 1836 err = -EINVAL; 1837 if (oh.error <= -1000 || oh.error > 0) 1838 goto err_finish; 1839 1840 spin_lock(&fc->lock); 1841 err = -ENOENT; 1842 if (!fc->connected) 1843 goto err_unlock; 1844 1845 req = request_find(fc, oh.unique); 1846 if (!req) 1847 goto err_unlock; 1848 1849 if (req->aborted) { 1850 spin_unlock(&fc->lock); 1851 fuse_copy_finish(cs); 1852 spin_lock(&fc->lock); 1853 request_end(fc, req); 1854 return -ENOENT; 1855 } 1856 /* Is it an interrupt reply? */ 1857 if (req->intr_unique == oh.unique) { 1858 err = -EINVAL; 1859 if (nbytes != sizeof(struct fuse_out_header)) 1860 goto err_unlock; 1861 1862 if (oh.error == -ENOSYS) 1863 fc->no_interrupt = 1; 1864 else if (oh.error == -EAGAIN) 1865 queue_interrupt(fc, req); 1866 1867 spin_unlock(&fc->lock); 1868 fuse_copy_finish(cs); 1869 return nbytes; 1870 } 1871 1872 req->state = FUSE_REQ_WRITING; 1873 list_move(&req->list, &fc->io); 1874 req->out.h = oh; 1875 req->locked = 1; 1876 cs->req = req; 1877 if (!req->out.page_replace) 1878 cs->move_pages = 0; 1879 spin_unlock(&fc->lock); 1880 1881 err = copy_out_args(cs, &req->out, nbytes); 1882 fuse_copy_finish(cs); 1883 1884 spin_lock(&fc->lock); 1885 req->locked = 0; 1886 if (!err) { 1887 if (req->aborted) 1888 err = -ENOENT; 1889 } else if (!req->aborted) 1890 req->out.h.error = -EIO; 1891 request_end(fc, req); 1892 1893 return err ? err : nbytes; 1894 1895 err_unlock: 1896 spin_unlock(&fc->lock); 1897 err_finish: 1898 fuse_copy_finish(cs); 1899 return err; 1900 } 1901 1902 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov, 1903 unsigned long nr_segs, loff_t pos) 1904 { 1905 struct fuse_copy_state cs; 1906 struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp); 1907 if (!fc) 1908 return -EPERM; 1909 1910 fuse_copy_init(&cs, fc, 0, iov, nr_segs); 1911 1912 return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs)); 1913 } 1914 1915 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe, 1916 struct file *out, loff_t *ppos, 1917 size_t len, unsigned int flags) 1918 { 1919 unsigned nbuf; 1920 unsigned idx; 1921 struct pipe_buffer *bufs; 1922 struct fuse_copy_state cs; 1923 struct fuse_conn *fc; 1924 size_t rem; 1925 ssize_t ret; 1926 1927 fc = fuse_get_conn(out); 1928 if (!fc) 1929 return -EPERM; 1930 1931 bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL); 1932 if (!bufs) 1933 return -ENOMEM; 1934 1935 pipe_lock(pipe); 1936 nbuf = 0; 1937 rem = 0; 1938 for (idx = 0; idx < pipe->nrbufs && rem < len; idx++) 1939 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len; 1940 1941 ret = -EINVAL; 1942 if (rem < len) { 1943 pipe_unlock(pipe); 1944 goto out; 1945 } 1946 1947 rem = len; 1948 while (rem) { 1949 struct pipe_buffer *ibuf; 1950 struct pipe_buffer *obuf; 1951 1952 BUG_ON(nbuf >= pipe->buffers); 1953 BUG_ON(!pipe->nrbufs); 1954 ibuf = &pipe->bufs[pipe->curbuf]; 1955 obuf = &bufs[nbuf]; 1956 1957 if (rem >= ibuf->len) { 1958 *obuf = *ibuf; 1959 ibuf->ops = NULL; 1960 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1); 1961 pipe->nrbufs--; 1962 } else { 1963 ibuf->ops->get(pipe, ibuf); 1964 *obuf = *ibuf; 1965 obuf->flags &= ~PIPE_BUF_FLAG_GIFT; 1966 obuf->len = rem; 1967 ibuf->offset += obuf->len; 1968 ibuf->len -= obuf->len; 1969 } 1970 nbuf++; 1971 rem -= obuf->len; 1972 } 1973 pipe_unlock(pipe); 1974 1975 fuse_copy_init(&cs, fc, 0, NULL, nbuf); 1976 cs.pipebufs = bufs; 1977 cs.pipe = pipe; 1978 1979 if (flags & SPLICE_F_MOVE) 1980 cs.move_pages = 1; 1981 1982 ret = fuse_dev_do_write(fc, &cs, len); 1983 1984 for (idx = 0; idx < nbuf; idx++) { 1985 struct pipe_buffer *buf = &bufs[idx]; 1986 buf->ops->release(pipe, buf); 1987 } 1988 out: 1989 kfree(bufs); 1990 return ret; 1991 } 1992 1993 static unsigned fuse_dev_poll(struct file *file, poll_table *wait) 1994 { 1995 unsigned mask = POLLOUT | POLLWRNORM; 1996 struct fuse_conn *fc = fuse_get_conn(file); 1997 if (!fc) 1998 return POLLERR; 1999 2000 poll_wait(file, &fc->waitq, wait); 2001 2002 spin_lock(&fc->lock); 2003 if (!fc->connected) 2004 mask = POLLERR; 2005 else if (request_pending(fc)) 2006 mask |= POLLIN | POLLRDNORM; 2007 spin_unlock(&fc->lock); 2008 2009 return mask; 2010 } 2011 2012 /* 2013 * Abort all requests on the given list (pending or processing) 2014 * 2015 * This function releases and reacquires fc->lock 2016 */ 2017 static void end_requests(struct fuse_conn *fc, struct list_head *head) 2018 __releases(fc->lock) 2019 __acquires(fc->lock) 2020 { 2021 while (!list_empty(head)) { 2022 struct fuse_req *req; 2023 req = list_entry(head->next, struct fuse_req, list); 2024 req->out.h.error = -ECONNABORTED; 2025 request_end(fc, req); 2026 spin_lock(&fc->lock); 2027 } 2028 } 2029 2030 /* 2031 * Abort requests under I/O 2032 * 2033 * The requests are set to aborted and finished, and the request 2034 * waiter is woken up. This will make request_wait_answer() wait 2035 * until the request is unlocked and then return. 2036 * 2037 * If the request is asynchronous, then the end function needs to be 2038 * called after waiting for the request to be unlocked (if it was 2039 * locked). 2040 */ 2041 static void end_io_requests(struct fuse_conn *fc) 2042 __releases(fc->lock) 2043 __acquires(fc->lock) 2044 { 2045 while (!list_empty(&fc->io)) { 2046 struct fuse_req *req = 2047 list_entry(fc->io.next, struct fuse_req, list); 2048 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end; 2049 2050 req->aborted = 1; 2051 req->out.h.error = -ECONNABORTED; 2052 req->state = FUSE_REQ_FINISHED; 2053 list_del_init(&req->list); 2054 wake_up(&req->waitq); 2055 if (end) { 2056 req->end = NULL; 2057 __fuse_get_request(req); 2058 spin_unlock(&fc->lock); 2059 wait_event(req->waitq, !req->locked); 2060 end(fc, req); 2061 fuse_put_request(fc, req); 2062 spin_lock(&fc->lock); 2063 } 2064 } 2065 } 2066 2067 static void end_queued_requests(struct fuse_conn *fc) 2068 __releases(fc->lock) 2069 __acquires(fc->lock) 2070 { 2071 fc->max_background = UINT_MAX; 2072 flush_bg_queue(fc); 2073 end_requests(fc, &fc->pending); 2074 end_requests(fc, &fc->processing); 2075 while (forget_pending(fc)) 2076 kfree(dequeue_forget(fc, 1, NULL)); 2077 } 2078 2079 static void end_polls(struct fuse_conn *fc) 2080 { 2081 struct rb_node *p; 2082 2083 p = rb_first(&fc->polled_files); 2084 2085 while (p) { 2086 struct fuse_file *ff; 2087 ff = rb_entry(p, struct fuse_file, polled_node); 2088 wake_up_interruptible_all(&ff->poll_wait); 2089 2090 p = rb_next(p); 2091 } 2092 } 2093 2094 /* 2095 * Abort all requests. 2096 * 2097 * Emergency exit in case of a malicious or accidental deadlock, or 2098 * just a hung filesystem. 2099 * 2100 * The same effect is usually achievable through killing the 2101 * filesystem daemon and all users of the filesystem. The exception 2102 * is the combination of an asynchronous request and the tricky 2103 * deadlock (see Documentation/filesystems/fuse.txt). 2104 * 2105 * During the aborting, progression of requests from the pending and 2106 * processing lists onto the io list, and progression of new requests 2107 * onto the pending list is prevented by req->connected being false. 2108 * 2109 * Progression of requests under I/O to the processing list is 2110 * prevented by the req->aborted flag being true for these requests. 2111 * For this reason requests on the io list must be aborted first. 2112 */ 2113 void fuse_abort_conn(struct fuse_conn *fc) 2114 { 2115 spin_lock(&fc->lock); 2116 if (fc->connected) { 2117 fc->connected = 0; 2118 fc->blocked = 0; 2119 fc->initialized = 1; 2120 end_io_requests(fc); 2121 end_queued_requests(fc); 2122 end_polls(fc); 2123 wake_up_all(&fc->waitq); 2124 wake_up_all(&fc->blocked_waitq); 2125 kill_fasync(&fc->fasync, SIGIO, POLL_IN); 2126 } 2127 spin_unlock(&fc->lock); 2128 } 2129 EXPORT_SYMBOL_GPL(fuse_abort_conn); 2130 2131 int fuse_dev_release(struct inode *inode, struct file *file) 2132 { 2133 struct fuse_conn *fc = fuse_get_conn(file); 2134 if (fc) { 2135 spin_lock(&fc->lock); 2136 fc->connected = 0; 2137 fc->blocked = 0; 2138 fc->initialized = 1; 2139 end_queued_requests(fc); 2140 end_polls(fc); 2141 wake_up_all(&fc->blocked_waitq); 2142 spin_unlock(&fc->lock); 2143 fuse_conn_put(fc); 2144 } 2145 2146 return 0; 2147 } 2148 EXPORT_SYMBOL_GPL(fuse_dev_release); 2149 2150 static int fuse_dev_fasync(int fd, struct file *file, int on) 2151 { 2152 struct fuse_conn *fc = fuse_get_conn(file); 2153 if (!fc) 2154 return -EPERM; 2155 2156 /* No locking - fasync_helper does its own locking */ 2157 return fasync_helper(fd, file, on, &fc->fasync); 2158 } 2159 2160 const struct file_operations fuse_dev_operations = { 2161 .owner = THIS_MODULE, 2162 .llseek = no_llseek, 2163 .read = do_sync_read, 2164 .aio_read = fuse_dev_read, 2165 .splice_read = fuse_dev_splice_read, 2166 .write = do_sync_write, 2167 .aio_write = fuse_dev_write, 2168 .splice_write = fuse_dev_splice_write, 2169 .poll = fuse_dev_poll, 2170 .release = fuse_dev_release, 2171 .fasync = fuse_dev_fasync, 2172 }; 2173 EXPORT_SYMBOL_GPL(fuse_dev_operations); 2174 2175 static struct miscdevice fuse_miscdevice = { 2176 .minor = FUSE_MINOR, 2177 .name = "fuse", 2178 .fops = &fuse_dev_operations, 2179 }; 2180 2181 int __init fuse_dev_init(void) 2182 { 2183 int err = -ENOMEM; 2184 fuse_req_cachep = kmem_cache_create("fuse_request", 2185 sizeof(struct fuse_req), 2186 0, 0, NULL); 2187 if (!fuse_req_cachep) 2188 goto out; 2189 2190 err = misc_register(&fuse_miscdevice); 2191 if (err) 2192 goto out_cache_clean; 2193 2194 return 0; 2195 2196 out_cache_clean: 2197 kmem_cache_destroy(fuse_req_cachep); 2198 out: 2199 return err; 2200 } 2201 2202 void fuse_dev_cleanup(void) 2203 { 2204 misc_deregister(&fuse_miscdevice); 2205 kmem_cache_destroy(fuse_req_cachep); 2206 } 2207