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         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                         kunmap_atomic(cs->mapaddr);
 671                 } else {
 672                         kunmap_atomic(cs->mapaddr);
 673                         buf->len = PAGE_SIZE - cs->len;
 674                 }
 675                 cs->currbuf = NULL;
 676                 cs->mapaddr = NULL;
 677         } else if (cs->mapaddr) {
 678                 kunmap_atomic(cs->mapaddr);
 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 = kmap_atomic(buf->page);
 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_atomic(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_atomic(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 = kmap_atomic(buf->page);
 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 ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1300                                     struct pipe_inode_info *pipe,
1301                                     size_t len, unsigned int flags)
1302 {
1303         int ret;
1304         int page_nr = 0;
1305         int do_wakeup = 0;
1306         struct pipe_buffer *bufs;
1307         struct fuse_copy_state cs;
1308         struct fuse_conn *fc = fuse_get_conn(in);
1309         if (!fc)
1310                 return -EPERM;
1311
1312         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1313         if (!bufs)
1314                 return -ENOMEM;
1315
1316         fuse_copy_init(&cs, fc, 1, NULL, 0);
1317         cs.pipebufs = bufs;
1318         cs.pipe = pipe;
1319         ret = fuse_dev_do_read(fc, in, &cs, len);
1320         if (ret < 0)
1321                 goto out;
1322
1323         ret = 0;
1324         pipe_lock(pipe);
1325
1326         if (!pipe->readers) {
1327                 send_sig(SIGPIPE, current, 0);
1328                 if (!ret)
1329                         ret = -EPIPE;
1330                 goto out_unlock;
1331         }
1332
1333         if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1334                 ret = -EIO;
1335                 goto out_unlock;
1336         }
1337
1338         while (page_nr < cs.nr_segs) {
1339                 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1340                 struct pipe_buffer *buf = pipe->bufs + newbuf;
1341
1342                 buf->page = bufs[page_nr].page;
1343                 buf->offset = bufs[page_nr].offset;
1344                 buf->len = bufs[page_nr].len;
1345                 /*
1346                  * Need to be careful about this.  Having buf->ops in module
1347                  * code can Oops if the buffer persists after module unload.
1348                  */
1349                 buf->ops = &nosteal_pipe_buf_ops;
1350
1351                 pipe->nrbufs++;
1352                 page_nr++;
1353                 ret += buf->len;
1354
1355                 if (pipe->files)
1356                         do_wakeup = 1;
1357         }
1358
1359 out_unlock:
1360         pipe_unlock(pipe);
1361
1362         if (do_wakeup) {
1363                 smp_mb();
1364                 if (waitqueue_active(&pipe->wait))
1365                         wake_up_interruptible(&pipe->wait);
1366                 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1367         }
1368
1369 out:
1370         for (; page_nr < cs.nr_segs; page_nr++)
1371                 page_cache_release(bufs[page_nr].page);
1372
1373         kfree(bufs);
1374         return ret;
1375 }
1376
1377 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1378                             struct fuse_copy_state *cs)
1379 {
1380         struct fuse_notify_poll_wakeup_out outarg;
1381         int err = -EINVAL;
1382
1383         if (size != sizeof(outarg))
1384                 goto err;
1385
1386         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1387         if (err)
1388                 goto err;
1389
1390         fuse_copy_finish(cs);
1391         return fuse_notify_poll_wakeup(fc, &outarg);
1392
1393 err:
1394         fuse_copy_finish(cs);
1395         return err;
1396 }
1397
1398 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1399                                    struct fuse_copy_state *cs)
1400 {
1401         struct fuse_notify_inval_inode_out outarg;
1402         int err = -EINVAL;
1403
1404         if (size != sizeof(outarg))
1405                 goto err;
1406
1407         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1408         if (err)
1409                 goto err;
1410         fuse_copy_finish(cs);
1411
1412         down_read(&fc->killsb);
1413         err = -ENOENT;
1414         if (fc->sb) {
1415                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1416                                                outarg.off, outarg.len);
1417         }
1418         up_read(&fc->killsb);
1419         return err;
1420
1421 err:
1422         fuse_copy_finish(cs);
1423         return err;
1424 }
1425
1426 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1427                                    struct fuse_copy_state *cs)
1428 {
1429         struct fuse_notify_inval_entry_out outarg;
1430         int err = -ENOMEM;
1431         char *buf;
1432         struct qstr name;
1433
1434         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1435         if (!buf)
1436                 goto err;
1437
1438         err = -EINVAL;
1439         if (size < sizeof(outarg))
1440                 goto err;
1441
1442         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1443         if (err)
1444                 goto err;
1445
1446         err = -ENAMETOOLONG;
1447         if (outarg.namelen > FUSE_NAME_MAX)
1448                 goto err;
1449
1450         err = -EINVAL;
1451         if (size != sizeof(outarg) + outarg.namelen + 1)
1452                 goto err;
1453
1454         name.name = buf;
1455         name.len = outarg.namelen;
1456         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1457         if (err)
1458                 goto err;
1459         fuse_copy_finish(cs);
1460         buf[outarg.namelen] = 0;
1461         name.hash = full_name_hash(name.name, name.len);
1462
1463         down_read(&fc->killsb);
1464         err = -ENOENT;
1465         if (fc->sb)
1466                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1467         up_read(&fc->killsb);
1468         kfree(buf);
1469         return err;
1470
1471 err:
1472         kfree(buf);
1473         fuse_copy_finish(cs);
1474         return err;
1475 }
1476
1477 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1478                               struct fuse_copy_state *cs)
1479 {
1480         struct fuse_notify_delete_out outarg;
1481         int err = -ENOMEM;
1482         char *buf;
1483         struct qstr name;
1484
1485         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1486         if (!buf)
1487                 goto err;
1488
1489         err = -EINVAL;
1490         if (size < sizeof(outarg))
1491                 goto err;
1492
1493         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1494         if (err)
1495                 goto err;
1496
1497         err = -ENAMETOOLONG;
1498         if (outarg.namelen > FUSE_NAME_MAX)
1499                 goto err;
1500
1501         err = -EINVAL;
1502         if (size != sizeof(outarg) + outarg.namelen + 1)
1503                 goto err;
1504
1505         name.name = buf;
1506         name.len = outarg.namelen;
1507         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1508         if (err)
1509                 goto err;
1510         fuse_copy_finish(cs);
1511         buf[outarg.namelen] = 0;
1512         name.hash = full_name_hash(name.name, name.len);
1513
1514         down_read(&fc->killsb);
1515         err = -ENOENT;
1516         if (fc->sb)
1517                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1518                                                outarg.child, &name);
1519         up_read(&fc->killsb);
1520         kfree(buf);
1521         return err;
1522
1523 err:
1524         kfree(buf);
1525         fuse_copy_finish(cs);
1526         return err;
1527 }
1528
1529 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1530                              struct fuse_copy_state *cs)
1531 {
1532         struct fuse_notify_store_out outarg;
1533         struct inode *inode;
1534         struct address_space *mapping;
1535         u64 nodeid;
1536         int err;
1537         pgoff_t index;
1538         unsigned int offset;
1539         unsigned int num;
1540         loff_t file_size;
1541         loff_t end;
1542
1543         err = -EINVAL;
1544         if (size < sizeof(outarg))
1545                 goto out_finish;
1546
1547         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1548         if (err)
1549                 goto out_finish;
1550
1551         err = -EINVAL;
1552         if (size - sizeof(outarg) != outarg.size)
1553                 goto out_finish;
1554
1555         nodeid = outarg.nodeid;
1556
1557         down_read(&fc->killsb);
1558
1559         err = -ENOENT;
1560         if (!fc->sb)
1561                 goto out_up_killsb;
1562
1563         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1564         if (!inode)
1565                 goto out_up_killsb;
1566
1567         mapping = inode->i_mapping;
1568         index = outarg.offset >> PAGE_CACHE_SHIFT;
1569         offset = outarg.offset & ~PAGE_CACHE_MASK;
1570         file_size = i_size_read(inode);
1571         end = outarg.offset + outarg.size;
1572         if (end > file_size) {
1573                 file_size = end;
1574                 fuse_write_update_size(inode, file_size);
1575         }
1576
1577         num = outarg.size;
1578         while (num) {
1579                 struct page *page;
1580                 unsigned int this_num;
1581
1582                 err = -ENOMEM;
1583                 page = find_or_create_page(mapping, index,
1584                                            mapping_gfp_mask(mapping));
1585                 if (!page)
1586                         goto out_iput;
1587
1588                 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1589                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1590                 if (!err && offset == 0 &&
1591                     (this_num == PAGE_CACHE_SIZE || file_size == end))
1592                         SetPageUptodate(page);
1593                 unlock_page(page);
1594                 page_cache_release(page);
1595
1596                 if (err)
1597                         goto out_iput;
1598
1599                 num -= this_num;
1600                 offset = 0;
1601                 index++;
1602         }
1603
1604         err = 0;
1605
1606 out_iput:
1607         iput(inode);
1608 out_up_killsb:
1609         up_read(&fc->killsb);
1610 out_finish:
1611         fuse_copy_finish(cs);
1612         return err;
1613 }
1614
1615 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1616 {
1617         release_pages(req->pages, req->num_pages, false);
1618 }
1619
1620 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1621                          struct fuse_notify_retrieve_out *outarg)
1622 {
1623         int err;
1624         struct address_space *mapping = inode->i_mapping;
1625         struct fuse_req *req;
1626         pgoff_t index;
1627         loff_t file_size;
1628         unsigned int num;
1629         unsigned int offset;
1630         size_t total_len = 0;
1631         int num_pages;
1632
1633         offset = outarg->offset & ~PAGE_CACHE_MASK;
1634         file_size = i_size_read(inode);
1635
1636         num = outarg->size;
1637         if (outarg->offset > file_size)
1638                 num = 0;
1639         else if (outarg->offset + num > file_size)
1640                 num = file_size - outarg->offset;
1641
1642         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1643         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1644
1645         req = fuse_get_req(fc, num_pages);
1646         if (IS_ERR(req))
1647                 return PTR_ERR(req);
1648
1649         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1650         req->in.h.nodeid = outarg->nodeid;
1651         req->in.numargs = 2;
1652         req->in.argpages = 1;
1653         req->page_descs[0].offset = offset;
1654         req->end = fuse_retrieve_end;
1655
1656         index = outarg->offset >> PAGE_CACHE_SHIFT;
1657
1658         while (num && req->num_pages < num_pages) {
1659                 struct page *page;
1660                 unsigned int this_num;
1661
1662                 page = find_get_page(mapping, index);
1663                 if (!page)
1664                         break;
1665
1666                 this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1667                 req->pages[req->num_pages] = page;
1668                 req->page_descs[req->num_pages].length = this_num;
1669                 req->num_pages++;
1670
1671                 offset = 0;
1672                 num -= this_num;
1673                 total_len += this_num;
1674                 index++;
1675         }
1676         req->misc.retrieve_in.offset = outarg->offset;
1677         req->misc.retrieve_in.size = total_len;
1678         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1679         req->in.args[0].value = &req->misc.retrieve_in;
1680         req->in.args[1].size = total_len;
1681
1682         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1683         if (err)
1684                 fuse_retrieve_end(fc, req);
1685
1686         return err;
1687 }
1688
1689 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1690                                 struct fuse_copy_state *cs)
1691 {
1692         struct fuse_notify_retrieve_out outarg;
1693         struct inode *inode;
1694         int err;
1695
1696         err = -EINVAL;
1697         if (size != sizeof(outarg))
1698                 goto copy_finish;
1699
1700         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1701         if (err)
1702                 goto copy_finish;
1703
1704         fuse_copy_finish(cs);
1705
1706         down_read(&fc->killsb);
1707         err = -ENOENT;
1708         if (fc->sb) {
1709                 u64 nodeid = outarg.nodeid;
1710
1711                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1712                 if (inode) {
1713                         err = fuse_retrieve(fc, inode, &outarg);
1714                         iput(inode);
1715                 }
1716         }
1717         up_read(&fc->killsb);
1718
1719         return err;
1720
1721 copy_finish:
1722         fuse_copy_finish(cs);
1723         return err;
1724 }
1725
1726 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1727                        unsigned int size, struct fuse_copy_state *cs)
1728 {
1729         switch (code) {
1730         case FUSE_NOTIFY_POLL:
1731                 return fuse_notify_poll(fc, size, cs);
1732
1733         case FUSE_NOTIFY_INVAL_INODE:
1734                 return fuse_notify_inval_inode(fc, size, cs);
1735
1736         case FUSE_NOTIFY_INVAL_ENTRY:
1737                 return fuse_notify_inval_entry(fc, size, cs);
1738
1739         case FUSE_NOTIFY_STORE:
1740                 return fuse_notify_store(fc, size, cs);
1741
1742         case FUSE_NOTIFY_RETRIEVE:
1743                 return fuse_notify_retrieve(fc, size, cs);
1744
1745         case FUSE_NOTIFY_DELETE:
1746                 return fuse_notify_delete(fc, size, cs);
1747
1748         default:
1749                 fuse_copy_finish(cs);
1750                 return -EINVAL;
1751         }
1752 }
1753
1754 /* Look up request on processing list by unique ID */
1755 static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1756 {
1757         struct fuse_req *req;
1758
1759         list_for_each_entry(req, &fc->processing, list) {
1760                 if (req->in.h.unique == unique || req->intr_unique == unique)
1761                         return req;
1762         }
1763         return NULL;
1764 }
1765
1766 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1767                          unsigned nbytes)
1768 {
1769         unsigned reqsize = sizeof(struct fuse_out_header);
1770
1771         if (out->h.error)
1772                 return nbytes != reqsize ? -EINVAL : 0;
1773
1774         reqsize += len_args(out->numargs, out->args);
1775
1776         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1777                 return -EINVAL;
1778         else if (reqsize > nbytes) {
1779                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1780                 unsigned diffsize = reqsize - nbytes;
1781                 if (diffsize > lastarg->size)
1782                         return -EINVAL;
1783                 lastarg->size -= diffsize;
1784         }
1785         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1786                               out->page_zeroing);
1787 }
1788
1789 /*
1790  * Write a single reply to a request.  First the header is copied from
1791  * the write buffer.  The request is then searched on the processing
1792  * list by the unique ID found in the header.  If found, then remove
1793  * it from the list and copy the rest of the buffer to the request.
1794  * The request is finished by calling request_end()
1795  */
1796 static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1797                                  struct fuse_copy_state *cs, size_t nbytes)
1798 {
1799         int err;
1800         struct fuse_req *req;
1801         struct fuse_out_header oh;
1802
1803         if (nbytes < sizeof(struct fuse_out_header))
1804                 return -EINVAL;
1805
1806         err = fuse_copy_one(cs, &oh, sizeof(oh));
1807         if (err)
1808                 goto err_finish;
1809
1810         err = -EINVAL;
1811         if (oh.len != nbytes)
1812                 goto err_finish;
1813
1814         /*
1815          * Zero oh.unique indicates unsolicited notification message
1816          * and error contains notification code.
1817          */
1818         if (!oh.unique) {
1819                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1820                 return err ? err : nbytes;
1821         }
1822
1823         err = -EINVAL;
1824         if (oh.error <= -1000 || oh.error > 0)
1825                 goto err_finish;
1826
1827         spin_lock(&fc->lock);
1828         err = -ENOENT;
1829         if (!fc->connected)
1830                 goto err_unlock;
1831
1832         req = request_find(fc, oh.unique);
1833         if (!req)
1834                 goto err_unlock;
1835
1836         if (req->aborted) {
1837                 spin_unlock(&fc->lock);
1838                 fuse_copy_finish(cs);
1839                 spin_lock(&fc->lock);
1840                 request_end(fc, req);
1841                 return -ENOENT;
1842         }
1843         /* Is it an interrupt reply? */
1844         if (req->intr_unique == oh.unique) {
1845                 err = -EINVAL;
1846                 if (nbytes != sizeof(struct fuse_out_header))
1847                         goto err_unlock;
1848
1849                 if (oh.error == -ENOSYS)
1850                         fc->no_interrupt = 1;
1851                 else if (oh.error == -EAGAIN)
1852                         queue_interrupt(fc, req);
1853
1854                 spin_unlock(&fc->lock);
1855                 fuse_copy_finish(cs);
1856                 return nbytes;
1857         }
1858
1859         req->state = FUSE_REQ_WRITING;
1860         list_move(&req->list, &fc->io);
1861         req->out.h = oh;
1862         req->locked = 1;
1863         cs->req = req;
1864         if (!req->out.page_replace)
1865                 cs->move_pages = 0;
1866         spin_unlock(&fc->lock);
1867
1868         err = copy_out_args(cs, &req->out, nbytes);
1869         fuse_copy_finish(cs);
1870
1871         spin_lock(&fc->lock);
1872         req->locked = 0;
1873         if (!err) {
1874                 if (req->aborted)
1875                         err = -ENOENT;
1876         } else if (!req->aborted)
1877                 req->out.h.error = -EIO;
1878         request_end(fc, req);
1879
1880         return err ? err : nbytes;
1881
1882  err_unlock:
1883         spin_unlock(&fc->lock);
1884  err_finish:
1885         fuse_copy_finish(cs);
1886         return err;
1887 }
1888
1889 static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1890                               unsigned long nr_segs, loff_t pos)
1891 {
1892         struct fuse_copy_state cs;
1893         struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1894         if (!fc)
1895                 return -EPERM;
1896
1897         fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1898
1899         return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1900 }
1901
1902 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1903                                      struct file *out, loff_t *ppos,
1904                                      size_t len, unsigned int flags)
1905 {
1906         unsigned nbuf;
1907         unsigned idx;
1908         struct pipe_buffer *bufs;
1909         struct fuse_copy_state cs;
1910         struct fuse_conn *fc;
1911         size_t rem;
1912         ssize_t ret;
1913
1914         fc = fuse_get_conn(out);
1915         if (!fc)
1916                 return -EPERM;
1917
1918         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1919         if (!bufs)
1920                 return -ENOMEM;
1921
1922         pipe_lock(pipe);
1923         nbuf = 0;
1924         rem = 0;
1925         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1926                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1927
1928         ret = -EINVAL;
1929         if (rem < len) {
1930                 pipe_unlock(pipe);
1931                 goto out;
1932         }
1933
1934         rem = len;
1935         while (rem) {
1936                 struct pipe_buffer *ibuf;
1937                 struct pipe_buffer *obuf;
1938
1939                 BUG_ON(nbuf >= pipe->buffers);
1940                 BUG_ON(!pipe->nrbufs);
1941                 ibuf = &pipe->bufs[pipe->curbuf];
1942                 obuf = &bufs[nbuf];
1943
1944                 if (rem >= ibuf->len) {
1945                         *obuf = *ibuf;
1946                         ibuf->ops = NULL;
1947                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1948                         pipe->nrbufs--;
1949                 } else {
1950                         ibuf->ops->get(pipe, ibuf);
1951                         *obuf = *ibuf;
1952                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1953                         obuf->len = rem;
1954                         ibuf->offset += obuf->len;
1955                         ibuf->len -= obuf->len;
1956                 }
1957                 nbuf++;
1958                 rem -= obuf->len;
1959         }
1960         pipe_unlock(pipe);
1961
1962         fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1963         cs.pipebufs = bufs;
1964         cs.pipe = pipe;
1965
1966         if (flags & SPLICE_F_MOVE)
1967                 cs.move_pages = 1;
1968
1969         ret = fuse_dev_do_write(fc, &cs, len);
1970
1971         for (idx = 0; idx < nbuf; idx++) {
1972                 struct pipe_buffer *buf = &bufs[idx];
1973                 buf->ops->release(pipe, buf);
1974         }
1975 out:
1976         kfree(bufs);
1977         return ret;
1978 }
1979
1980 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1981 {
1982         unsigned mask = POLLOUT | POLLWRNORM;
1983         struct fuse_conn *fc = fuse_get_conn(file);
1984         if (!fc)
1985                 return POLLERR;
1986
1987         poll_wait(file, &fc->waitq, wait);
1988
1989         spin_lock(&fc->lock);
1990         if (!fc->connected)
1991                 mask = POLLERR;
1992         else if (request_pending(fc))
1993                 mask |= POLLIN | POLLRDNORM;
1994         spin_unlock(&fc->lock);
1995
1996         return mask;
1997 }
1998
1999 /*
2000  * Abort all requests on the given list (pending or processing)
2001  *
2002  * This function releases and reacquires fc->lock
2003  */
2004 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2005 __releases(fc->lock)
2006 __acquires(fc->lock)
2007 {
2008         while (!list_empty(head)) {
2009                 struct fuse_req *req;
2010                 req = list_entry(head->next, struct fuse_req, list);
2011                 req->out.h.error = -ECONNABORTED;
2012                 request_end(fc, req);
2013                 spin_lock(&fc->lock);
2014         }
2015 }
2016
2017 /*
2018  * Abort requests under I/O
2019  *
2020  * The requests are set to aborted and finished, and the request
2021  * waiter is woken up.  This will make request_wait_answer() wait
2022  * until the request is unlocked and then return.
2023  *
2024  * If the request is asynchronous, then the end function needs to be
2025  * called after waiting for the request to be unlocked (if it was
2026  * locked).
2027  */
2028 static void end_io_requests(struct fuse_conn *fc)
2029 __releases(fc->lock)
2030 __acquires(fc->lock)
2031 {
2032         while (!list_empty(&fc->io)) {
2033                 struct fuse_req *req =
2034                         list_entry(fc->io.next, struct fuse_req, list);
2035                 void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
2036
2037                 req->aborted = 1;
2038                 req->out.h.error = -ECONNABORTED;
2039                 req->state = FUSE_REQ_FINISHED;
2040                 list_del_init(&req->list);
2041                 wake_up(&req->waitq);
2042                 if (end) {
2043                         req->end = NULL;
2044                         __fuse_get_request(req);
2045                         spin_unlock(&fc->lock);
2046                         wait_event(req->waitq, !req->locked);
2047                         end(fc, req);
2048                         fuse_put_request(fc, req);
2049                         spin_lock(&fc->lock);
2050                 }
2051         }
2052 }
2053
2054 static void end_queued_requests(struct fuse_conn *fc)
2055 __releases(fc->lock)
2056 __acquires(fc->lock)
2057 {
2058         fc->max_background = UINT_MAX;
2059         flush_bg_queue(fc);
2060         end_requests(fc, &fc->pending);
2061         end_requests(fc, &fc->processing);
2062         while (forget_pending(fc))
2063                 kfree(dequeue_forget(fc, 1, NULL));
2064 }
2065
2066 static void end_polls(struct fuse_conn *fc)
2067 {
2068         struct rb_node *p;
2069
2070         p = rb_first(&fc->polled_files);
2071
2072         while (p) {
2073                 struct fuse_file *ff;
2074                 ff = rb_entry(p, struct fuse_file, polled_node);
2075                 wake_up_interruptible_all(&ff->poll_wait);
2076
2077                 p = rb_next(p);
2078         }
2079 }
2080
2081 /*
2082  * Abort all requests.
2083  *
2084  * Emergency exit in case of a malicious or accidental deadlock, or
2085  * just a hung filesystem.
2086  *
2087  * The same effect is usually achievable through killing the
2088  * filesystem daemon and all users of the filesystem.  The exception
2089  * is the combination of an asynchronous request and the tricky
2090  * deadlock (see Documentation/filesystems/fuse.txt).
2091  *
2092  * During the aborting, progression of requests from the pending and
2093  * processing lists onto the io list, and progression of new requests
2094  * onto the pending list is prevented by req->connected being false.
2095  *
2096  * Progression of requests under I/O to the processing list is
2097  * prevented by the req->aborted flag being true for these requests.
2098  * For this reason requests on the io list must be aborted first.
2099  */
2100 void fuse_abort_conn(struct fuse_conn *fc)
2101 {
2102         spin_lock(&fc->lock);
2103         if (fc->connected) {
2104                 fc->connected = 0;
2105                 fc->blocked = 0;
2106                 fc->initialized = 1;
2107                 end_io_requests(fc);
2108                 end_queued_requests(fc);
2109                 end_polls(fc);
2110                 wake_up_all(&fc->waitq);
2111                 wake_up_all(&fc->blocked_waitq);
2112                 kill_fasync(&fc->fasync, SIGIO, POLL_IN);
2113         }
2114         spin_unlock(&fc->lock);
2115 }
2116 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2117
2118 int fuse_dev_release(struct inode *inode, struct file *file)
2119 {
2120         struct fuse_conn *fc = fuse_get_conn(file);
2121         if (fc) {
2122                 spin_lock(&fc->lock);
2123                 fc->connected = 0;
2124                 fc->blocked = 0;
2125                 fc->initialized = 1;
2126                 end_queued_requests(fc);
2127                 end_polls(fc);
2128                 wake_up_all(&fc->blocked_waitq);
2129                 spin_unlock(&fc->lock);
2130                 fuse_conn_put(fc);
2131         }
2132
2133         return 0;
2134 }
2135 EXPORT_SYMBOL_GPL(fuse_dev_release);
2136
2137 static int fuse_dev_fasync(int fd, struct file *file, int on)
2138 {
2139         struct fuse_conn *fc = fuse_get_conn(file);
2140         if (!fc)
2141                 return -EPERM;
2142
2143         /* No locking - fasync_helper does its own locking */
2144         return fasync_helper(fd, file, on, &fc->fasync);
2145 }
2146
2147 const struct file_operations fuse_dev_operations = {
2148         .owner          = THIS_MODULE,
2149         .llseek         = no_llseek,
2150         .read           = do_sync_read,
2151         .aio_read       = fuse_dev_read,
2152         .splice_read    = fuse_dev_splice_read,
2153         .write          = do_sync_write,
2154         .aio_write      = fuse_dev_write,
2155         .splice_write   = fuse_dev_splice_write,
2156         .poll           = fuse_dev_poll,
2157         .release        = fuse_dev_release,
2158         .fasync         = fuse_dev_fasync,
2159 };
2160 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2161
2162 static struct miscdevice fuse_miscdevice = {
2163         .minor = FUSE_MINOR,
2164         .name  = "fuse",
2165         .fops = &fuse_dev_operations,
2166 };
2167
2168 int __init fuse_dev_init(void)
2169 {
2170         int err = -ENOMEM;
2171         fuse_req_cachep = kmem_cache_create("fuse_request",
2172                                             sizeof(struct fuse_req),
2173                                             0, 0, NULL);
2174         if (!fuse_req_cachep)
2175                 goto out;
2176
2177         err = misc_register(&fuse_miscdevice);
2178         if (err)
2179                 goto out_cache_clean;
2180
2181         return 0;
2182
2183  out_cache_clean:
2184         kmem_cache_destroy(fuse_req_cachep);
2185  out:
2186         return err;
2187 }
2188
2189 void fuse_dev_cleanup(void)
2190 {
2191         misc_deregister(&fuse_miscdevice);
2192         kmem_cache_destroy(fuse_req_cachep);
2193 }