fs/fuse/dev.c

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