fs/fuse/dev.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  Miklos Szeredi <[email protected]>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/poll.h>
  14 #include <linux/sched/signal.h>
  15 #include <linux/uio.h>
  16 #include <linux/miscdevice.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/file.h>
  19 #include <linux/slab.h>
  20 #include <linux/pipe_fs_i.h>
  21 #include <linux/swap.h>
  22 #include <linux/splice.h>
  23 #include <linux/sched.h>
  24
  25 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
  26 MODULE_ALIAS("devname:fuse");
  27
  28 static struct kmem_cache *fuse_req_cachep;
  29
  30 static struct fuse_dev *fuse_get_dev(struct file *file)
  31 {
  32         /*
  33          * Lockless access is OK, because file->private data is set
  34          * once during mount and is valid until the file is released.
  35          */
  36         return READ_ONCE(file->private_data);
  37 }
  38
  39 static void fuse_request_init(struct fuse_req *req, struct page **pages,
  40                               struct fuse_page_desc *page_descs,
  41                               unsigned npages)
  42 {
  43         memset(req, 0, sizeof(*req));
  44         memset(pages, 0, sizeof(*pages) * npages);
  45         memset(page_descs, 0, sizeof(*page_descs) * npages);
  46         INIT_LIST_HEAD(&req->list);
  47         INIT_LIST_HEAD(&req->intr_entry);
  48         init_waitqueue_head(&req->waitq);
  49         refcount_set(&req->count, 1);
  50         req->pages = pages;
  51         req->page_descs = page_descs;
  52         req->max_pages = npages;
  53         __set_bit(FR_PENDING, &req->flags);
  54 }
  55
  56 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
  57 {
  58         struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
  59         if (req) {
  60                 struct page **pages;
  61                 struct fuse_page_desc *page_descs;
  62
  63                 if (npages <= FUSE_REQ_INLINE_PAGES) {
  64                         pages = req->inline_pages;
  65                         page_descs = req->inline_page_descs;
  66                 } else {
  67                         pages = kmalloc_array(npages, sizeof(struct page *),
  68                                               flags);
  69                         page_descs =
  70                                 kmalloc_array(npages,
  71                                               sizeof(struct fuse_page_desc),
  72                                               flags);
  73                 }
  74
  75                 if (!pages || !page_descs) {
  76                         kfree(pages);
  77                         kfree(page_descs);
  78                         kmem_cache_free(fuse_req_cachep, req);
  79                         return NULL;
  80                 }
  81
  82                 fuse_request_init(req, pages, page_descs, npages);
  83         }
  84         return req;
  85 }
  86
  87 struct fuse_req *fuse_request_alloc(unsigned npages)
  88 {
  89         return __fuse_request_alloc(npages, GFP_KERNEL);
  90 }
  91 EXPORT_SYMBOL_GPL(fuse_request_alloc);
  92
  93 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
  94 {
  95         return __fuse_request_alloc(npages, GFP_NOFS);
  96 }
  97
  98 void fuse_request_free(struct fuse_req *req)
  99 {
 100         if (req->pages != req->inline_pages) {
 101                 kfree(req->pages);
 102                 kfree(req->page_descs);
 103         }
 104         kmem_cache_free(fuse_req_cachep, req);
 105 }
 106
 107 void __fuse_get_request(struct fuse_req *req)
 108 {
 109         refcount_inc(&req->count);
 110 }
 111
 112 /* Must be called with > 1 refcount */
 113 static void __fuse_put_request(struct fuse_req *req)
 114 {
 115         refcount_dec(&req->count);
 116 }
 117
 118 void fuse_set_initialized(struct fuse_conn *fc)
 119 {
 120         /* Make sure stores before this are seen on another CPU */
 121         smp_wmb();
 122         fc->initialized = 1;
 123 }
 124
 125 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 126 {
 127         return !fc->initialized || (for_background && fc->blocked);
 128 }
 129
 130 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
 131                                        bool for_background)
 132 {
 133         struct fuse_req *req;
 134         int err;
 135         atomic_inc(&fc->num_waiting);
 136
 137         if (fuse_block_alloc(fc, for_background)) {
 138                 err = -EINTR;
 139                 if (wait_event_killable_exclusive(fc->blocked_waitq,
 140                                 !fuse_block_alloc(fc, for_background)))
 141                         goto out;
 142         }
 143         /* Matches smp_wmb() in fuse_set_initialized() */
 144         smp_rmb();
 145
 146         err = -ENOTCONN;
 147         if (!fc->connected)
 148                 goto out;
 149
 150         err = -ECONNREFUSED;
 151         if (fc->conn_error)
 152                 goto out;
 153
 154         req = fuse_request_alloc(npages);
 155         err = -ENOMEM;
 156         if (!req) {
 157                 if (for_background)
 158                         wake_up(&fc->blocked_waitq);
 159                 goto out;
 160         }
 161
 162         req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
 163         req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
 164         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 165
 166         __set_bit(FR_WAITING, &req->flags);
 167         if (for_background)
 168                 __set_bit(FR_BACKGROUND, &req->flags);
 169
 170         if (unlikely(req->in.h.uid == ((uid_t)-1) ||
 171                      req->in.h.gid == ((gid_t)-1))) {
 172                 fuse_put_request(fc, req);
 173                 return ERR_PTR(-EOVERFLOW);
 174         }
 175         return req;
 176
 177  out:
 178         atomic_dec(&fc->num_waiting);
 179         return ERR_PTR(err);
 180 }
 181
 182 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
 183 {
 184         return __fuse_get_req(fc, npages, false);
 185 }
 186 EXPORT_SYMBOL_GPL(fuse_get_req);
 187
 188 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 189                                              unsigned npages)
 190 {
 191         return __fuse_get_req(fc, npages, true);
 192 }
 193 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
 194
 195 /*
 196  * Return request in fuse_file->reserved_req.  However that may
 197  * currently be in use.  If that is the case, wait for it to become
 198  * available.
 199  */
 200 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
 201                                          struct file *file)
 202 {
 203         struct fuse_req *req = NULL;
 204         struct fuse_file *ff = file->private_data;
 205
 206         do {
 207                 wait_event(fc->reserved_req_waitq, ff->reserved_req);
 208                 spin_lock(&fc->lock);
 209                 if (ff->reserved_req) {
 210                         req = ff->reserved_req;
 211                         ff->reserved_req = NULL;
 212                         req->stolen_file = get_file(file);
 213                 }
 214                 spin_unlock(&fc->lock);
 215         } while (!req);
 216
 217         return req;
 218 }
 219
 220 /*
 221  * Put stolen request back into fuse_file->reserved_req
 222  */
 223 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
 224 {
 225         struct file *file = req->stolen_file;
 226         struct fuse_file *ff = file->private_data;
 227
 228         spin_lock(&fc->lock);
 229         fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
 230         BUG_ON(ff->reserved_req);
 231         ff->reserved_req = req;
 232         wake_up_all(&fc->reserved_req_waitq);
 233         spin_unlock(&fc->lock);
 234         fput(file);
 235 }
 236
 237 /*
 238  * Gets a requests for a file operation, always succeeds
 239  *
 240  * This is used for sending the FLUSH request, which must get to
 241  * userspace, due to POSIX locks which may need to be unlocked.
 242  *
 243  * If allocation fails due to OOM, use the reserved request in
 244  * fuse_file.
 245  *
 246  * This is very unlikely to deadlock accidentally, since the
 247  * filesystem should not have it's own file open.  If deadlock is
 248  * intentional, it can still be broken by "aborting" the filesystem.
 249  */
 250 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 251                                              struct file *file)
 252 {
 253         struct fuse_req *req;
 254
 255         atomic_inc(&fc->num_waiting);
 256         wait_event(fc->blocked_waitq, fc->initialized);
 257         /* Matches smp_wmb() in fuse_set_initialized() */
 258         smp_rmb();
 259         req = fuse_request_alloc(0);
 260         if (!req)
 261                 req = get_reserved_req(fc, file);
 262
 263         req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
 264         req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
 265         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 266
 267         __set_bit(FR_WAITING, &req->flags);
 268         __clear_bit(FR_BACKGROUND, &req->flags);
 269         return req;
 270 }
 271
 272 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 273 {
 274         if (refcount_dec_and_test(&req->count)) {
 275                 if (test_bit(FR_BACKGROUND, &req->flags)) {
 276                         /*
 277                          * We get here in the unlikely case that a background
 278                          * request was allocated but not sent
 279                          */
 280                         spin_lock(&fc->lock);
 281                         if (!fc->blocked)
 282                                 wake_up(&fc->blocked_waitq);
 283                         spin_unlock(&fc->lock);
 284                 }
 285
 286                 if (test_bit(FR_WAITING, &req->flags)) {
 287                         __clear_bit(FR_WAITING, &req->flags);
 288                         atomic_dec(&fc->num_waiting);
 289                 }
 290
 291                 if (req->stolen_file)
 292                         put_reserved_req(fc, req);
 293                 else
 294                         fuse_request_free(req);
 295         }
 296 }
 297 EXPORT_SYMBOL_GPL(fuse_put_request);
 298
 299 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
 300 {
 301         unsigned nbytes = 0;
 302         unsigned i;
 303
 304         for (i = 0; i < numargs; i++)
 305                 nbytes += args[i].size;
 306
 307         return nbytes;
 308 }
 309
 310 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
 311 {
 312         return ++fiq->reqctr;
 313 }
 314
 315 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
 316 {
 317         req->in.h.len = sizeof(struct fuse_in_header) +
 318                 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
 319         list_add_tail(&req->list, &fiq->pending);
 320         wake_up_locked(&fiq->waitq);
 321         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 322 }
 323
 324 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 325                        u64 nodeid, u64 nlookup)
 326 {
 327         struct fuse_iqueue *fiq = &fc->iq;
 328
 329         forget->forget_one.nodeid = nodeid;
 330         forget->forget_one.nlookup = nlookup;
 331
 332         spin_lock(&fiq->waitq.lock);
 333         if (fiq->connected) {
 334                 fiq->forget_list_tail->next = forget;
 335                 fiq->forget_list_tail = forget;
 336                 wake_up_locked(&fiq->waitq);
 337                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 338         } else {
 339                 kfree(forget);
 340         }
 341         spin_unlock(&fiq->waitq.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                 struct fuse_iqueue *fiq = &fc->iq;
 350
 351                 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
 352                 list_del(&req->list);
 353                 fc->active_background++;
 354                 spin_lock(&fiq->waitq.lock);
 355                 req->in.h.unique = fuse_get_unique(fiq);
 356                 queue_request(fiq, req);
 357                 spin_unlock(&fiq->waitq.lock);
 358         }
 359 }
 360
 361 /*
 362  * This function is called when a request is finished.  Either a reply
 363  * has arrived or it was aborted (and not yet sent) or some error
 364  * occurred during communication with userspace, or the device file
 365  * was closed.  The requester thread is woken up (if still waiting),
 366  * the 'end' callback is called if given, else the reference to the
 367  * request is released
 368  */
 369 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 370 {
 371         struct fuse_iqueue *fiq = &fc->iq;
 372
 373         if (test_and_set_bit(FR_FINISHED, &req->flags))
 374                 return;
 375
 376         spin_lock(&fiq->waitq.lock);
 377         list_del_init(&req->intr_entry);
 378         spin_unlock(&fiq->waitq.lock);
 379         WARN_ON(test_bit(FR_PENDING, &req->flags));
 380         WARN_ON(test_bit(FR_SENT, &req->flags));
 381         if (test_bit(FR_BACKGROUND, &req->flags)) {
 382                 spin_lock(&fc->lock);
 383                 clear_bit(FR_BACKGROUND, &req->flags);
 384                 if (fc->num_background == fc->max_background)
 385                         fc->blocked = 0;
 386
 387                 /* Wake up next waiter, if any */
 388                 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
 389                         wake_up(&fc->blocked_waitq);
 390
 391                 if (fc->num_background == fc->congestion_threshold && fc->sb) {
 392                         clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 393                         clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 394                 }
 395                 fc->num_background--;
 396                 fc->active_background--;
 397                 flush_bg_queue(fc);
 398                 spin_unlock(&fc->lock);
 399         }
 400         wake_up(&req->waitq);
 401         if (req->end)
 402                 req->end(fc, req);
 403         fuse_put_request(fc, req);
 404 }
 405
 406 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
 407 {
 408         spin_lock(&fiq->waitq.lock);
 409         if (test_bit(FR_FINISHED, &req->flags)) {
 410                 spin_unlock(&fiq->waitq.lock);
 411                 return;
 412         }
 413         if (list_empty(&req->intr_entry)) {
 414                 list_add_tail(&req->intr_entry, &fiq->interrupts);
 415                 wake_up_locked(&fiq->waitq);
 416         }
 417         spin_unlock(&fiq->waitq.lock);
 418         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 419 }
 420
 421 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 422 {
 423         struct fuse_iqueue *fiq = &fc->iq;
 424         int err;
 425
 426         if (!fc->no_interrupt) {
 427                 /* Any signal may interrupt this */
 428                 err = wait_event_interruptible(req->waitq,
 429                                         test_bit(FR_FINISHED, &req->flags));
 430                 if (!err)
 431                         return;
 432
 433                 set_bit(FR_INTERRUPTED, &req->flags);
 434                 /* matches barrier in fuse_dev_do_read() */
 435                 smp_mb__after_atomic();
 436                 if (test_bit(FR_SENT, &req->flags))
 437                         queue_interrupt(fiq, req);
 438         }
 439
 440         if (!test_bit(FR_FORCE, &req->flags)) {
 441                 /* Only fatal signals may interrupt this */
 442                 err = wait_event_killable(req->waitq,
 443                                         test_bit(FR_FINISHED, &req->flags));
 444                 if (!err)
 445                         return;
 446
 447                 spin_lock(&fiq->waitq.lock);
 448                 /* Request is not yet in userspace, bail out */
 449                 if (test_bit(FR_PENDING, &req->flags)) {
 450                         list_del(&req->list);
 451                         spin_unlock(&fiq->waitq.lock);
 452                         __fuse_put_request(req);
 453                         req->out.h.error = -EINTR;
 454                         return;
 455                 }
 456                 spin_unlock(&fiq->waitq.lock);
 457         }
 458
 459         /*
 460          * Either request is already in userspace, or it was forced.
 461          * Wait it out.
 462          */
 463         wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
 464 }
 465
 466 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 467 {
 468         struct fuse_iqueue *fiq = &fc->iq;
 469
 470         BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
 471         spin_lock(&fiq->waitq.lock);
 472         if (!fiq->connected) {
 473                 spin_unlock(&fiq->waitq.lock);
 474                 req->out.h.error = -ENOTCONN;
 475         } else {
 476                 req->in.h.unique = fuse_get_unique(fiq);
 477                 queue_request(fiq, req);
 478                 /* acquire extra reference, since request is still needed
 479                    after request_end() */
 480                 __fuse_get_request(req);
 481                 spin_unlock(&fiq->waitq.lock);
 482
 483                 request_wait_answer(fc, req);
 484                 /* Pairs with smp_wmb() in request_end() */
 485                 smp_rmb();
 486         }
 487 }
 488
 489 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 490 {
 491         __set_bit(FR_ISREPLY, &req->flags);
 492         if (!test_bit(FR_WAITING, &req->flags)) {
 493                 __set_bit(FR_WAITING, &req->flags);
 494                 atomic_inc(&fc->num_waiting);
 495         }
 496         __fuse_request_send(fc, req);
 497 }
 498 EXPORT_SYMBOL_GPL(fuse_request_send);
 499
 500 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
 501 {
 502         if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
 503                 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
 504
 505         if (fc->minor < 9) {
 506                 switch (args->in.h.opcode) {
 507                 case FUSE_LOOKUP:
 508                 case FUSE_CREATE:
 509                 case FUSE_MKNOD:
 510                 case FUSE_MKDIR:
 511                 case FUSE_SYMLINK:
 512                 case FUSE_LINK:
 513                         args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 514                         break;
 515                 case FUSE_GETATTR:
 516                 case FUSE_SETATTR:
 517                         args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 518                         break;
 519                 }
 520         }
 521         if (fc->minor < 12) {
 522                 switch (args->in.h.opcode) {
 523                 case FUSE_CREATE:
 524                         args->in.args[0].size = sizeof(struct fuse_open_in);
 525                         break;
 526                 case FUSE_MKNOD:
 527                         args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
 528                         break;
 529                 }
 530         }
 531 }
 532
 533 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 534 {
 535         struct fuse_req *req;
 536         ssize_t ret;
 537
 538         req = fuse_get_req(fc, 0);
 539         if (IS_ERR(req))
 540                 return PTR_ERR(req);
 541
 542         /* Needs to be done after fuse_get_req() so that fc->minor is valid */
 543         fuse_adjust_compat(fc, args);
 544
 545         req->in.h.opcode = args->in.h.opcode;
 546         req->in.h.nodeid = args->in.h.nodeid;
 547         req->in.numargs = args->in.numargs;
 548         memcpy(req->in.args, args->in.args,
 549                args->in.numargs * sizeof(struct fuse_in_arg));
 550         req->out.argvar = args->out.argvar;
 551         req->out.numargs = args->out.numargs;
 552         memcpy(req->out.args, args->out.args,
 553                args->out.numargs * sizeof(struct fuse_arg));
 554         fuse_request_send(fc, req);
 555         ret = req->out.h.error;
 556         if (!ret && args->out.argvar) {
 557                 BUG_ON(args->out.numargs != 1);
 558                 ret = req->out.args[0].size;
 559         }
 560         fuse_put_request(fc, req);
 561
 562         return ret;
 563 }
 564
 565 /*
 566  * Called under fc->lock
 567  *
 568  * fc->connected must have been checked previously
 569  */
 570 void fuse_request_send_background_locked(struct fuse_conn *fc,
 571                                          struct fuse_req *req)
 572 {
 573         BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
 574         if (!test_bit(FR_WAITING, &req->flags)) {
 575                 __set_bit(FR_WAITING, &req->flags);
 576                 atomic_inc(&fc->num_waiting);
 577         }
 578         __set_bit(FR_ISREPLY, &req->flags);
 579         fc->num_background++;
 580         if (fc->num_background == fc->max_background)
 581                 fc->blocked = 1;
 582         if (fc->num_background == fc->congestion_threshold && fc->sb) {
 583                 set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 584                 set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 585         }
 586         list_add_tail(&req->list, &fc->bg_queue);
 587         flush_bg_queue(fc);
 588 }
 589
 590 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
 591 {
 592         BUG_ON(!req->end);
 593         spin_lock(&fc->lock);
 594         if (fc->connected) {
 595                 fuse_request_send_background_locked(fc, req);
 596                 spin_unlock(&fc->lock);
 597         } else {
 598                 spin_unlock(&fc->lock);
 599                 req->out.h.error = -ENOTCONN;
 600                 req->end(fc, req);
 601                 fuse_put_request(fc, req);
 602         }
 603 }
 604 EXPORT_SYMBOL_GPL(fuse_request_send_background);
 605
 606 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
 607                                           struct fuse_req *req, u64 unique)
 608 {
 609         int err = -ENODEV;
 610         struct fuse_iqueue *fiq = &fc->iq;
 611
 612         __clear_bit(FR_ISREPLY, &req->flags);
 613         req->in.h.unique = unique;
 614         spin_lock(&fiq->waitq.lock);
 615         if (fiq->connected) {
 616                 queue_request(fiq, req);
 617                 err = 0;
 618         }
 619         spin_unlock(&fiq->waitq.lock);
 620
 621         return err;
 622 }
 623
 624 void fuse_force_forget(struct file *file, u64 nodeid)
 625 {
 626         struct inode *inode = file_inode(file);
 627         struct fuse_conn *fc = get_fuse_conn(inode);
 628         struct fuse_req *req;
 629         struct fuse_forget_in inarg;
 630
 631         memset(&inarg, 0, sizeof(inarg));
 632         inarg.nlookup = 1;
 633         req = fuse_get_req_nofail_nopages(fc, file);
 634         req->in.h.opcode = FUSE_FORGET;
 635         req->in.h.nodeid = nodeid;
 636         req->in.numargs = 1;
 637         req->in.args[0].size = sizeof(inarg);
 638         req->in.args[0].value = &inarg;
 639         __clear_bit(FR_ISREPLY, &req->flags);
 640         __fuse_request_send(fc, req);
 641         /* ignore errors */
 642         fuse_put_request(fc, req);
 643 }
 644
 645 /*
 646  * Lock the request.  Up to the next unlock_request() there mustn't be
 647  * anything that could cause a page-fault.  If the request was already
 648  * aborted bail out.
 649  */
 650 static int lock_request(struct fuse_req *req)
 651 {
 652         int err = 0;
 653         if (req) {
 654                 spin_lock(&req->waitq.lock);
 655                 if (test_bit(FR_ABORTED, &req->flags))
 656                         err = -ENOENT;
 657                 else
 658                         set_bit(FR_LOCKED, &req->flags);
 659                 spin_unlock(&req->waitq.lock);
 660         }
 661         return err;
 662 }
 663
 664 /*
 665  * Unlock request.  If it was aborted while locked, caller is responsible
 666  * for unlocking and ending the request.
 667  */
 668 static int unlock_request(struct fuse_req *req)
 669 {
 670         int err = 0;
 671         if (req) {
 672                 spin_lock(&req->waitq.lock);
 673                 if (test_bit(FR_ABORTED, &req->flags))
 674                         err = -ENOENT;
 675                 else
 676                         clear_bit(FR_LOCKED, &req->flags);
 677                 spin_unlock(&req->waitq.lock);
 678         }
 679         return err;
 680 }
 681
 682 struct fuse_copy_state {
 683         int write;
 684         struct fuse_req *req;
 685         struct iov_iter *iter;
 686         struct pipe_buffer *pipebufs;
 687         struct pipe_buffer *currbuf;
 688         struct pipe_inode_info *pipe;
 689         unsigned long nr_segs;
 690         struct page *pg;
 691         unsigned len;
 692         unsigned offset;
 693         unsigned move_pages:1;
 694 };
 695
 696 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
 697                            struct iov_iter *iter)
 698 {
 699         memset(cs, 0, sizeof(*cs));
 700         cs->write = write;
 701         cs->iter = iter;
 702 }
 703
 704 /* Unmap and put previous page of userspace buffer */
 705 static void fuse_copy_finish(struct fuse_copy_state *cs)
 706 {
 707         if (cs->currbuf) {
 708                 struct pipe_buffer *buf = cs->currbuf;
 709
 710                 if (cs->write)
 711                         buf->len = PAGE_SIZE - cs->len;
 712                 cs->currbuf = NULL;
 713         } else if (cs->pg) {
 714                 if (cs->write) {
 715                         flush_dcache_page(cs->pg);
 716                         set_page_dirty_lock(cs->pg);
 717                 }
 718                 put_page(cs->pg);
 719         }
 720         cs->pg = NULL;
 721 }
 722
 723 /*
 724  * Get another pagefull of userspace buffer, and map it to kernel
 725  * address space, and lock request
 726  */
 727 static int fuse_copy_fill(struct fuse_copy_state *cs)
 728 {
 729         struct page *page;
 730         int err;
 731
 732         err = unlock_request(cs->req);
 733         if (err)
 734                 return err;
 735
 736         fuse_copy_finish(cs);
 737         if (cs->pipebufs) {
 738                 struct pipe_buffer *buf = cs->pipebufs;
 739
 740                 if (!cs->write) {
 741                         err = pipe_buf_confirm(cs->pipe, buf);
 742                         if (err)
 743                                 return err;
 744
 745                         BUG_ON(!cs->nr_segs);
 746                         cs->currbuf = buf;
 747                         cs->pg = buf->page;
 748                         cs->offset = buf->offset;
 749                         cs->len = buf->len;
 750                         cs->pipebufs++;
 751                         cs->nr_segs--;
 752                 } else {
 753                         if (cs->nr_segs == cs->pipe->buffers)
 754                                 return -EIO;
 755
 756                         page = alloc_page(GFP_HIGHUSER);
 757                         if (!page)
 758                                 return -ENOMEM;
 759
 760                         buf->page = page;
 761                         buf->offset = 0;
 762                         buf->len = 0;
 763
 764                         cs->currbuf = buf;
 765                         cs->pg = page;
 766                         cs->offset = 0;
 767                         cs->len = PAGE_SIZE;
 768                         cs->pipebufs++;
 769                         cs->nr_segs++;
 770                 }
 771         } else {
 772                 size_t off;
 773                 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
 774                 if (err < 0)
 775                         return err;
 776                 BUG_ON(!err);
 777                 cs->len = err;
 778                 cs->offset = off;
 779                 cs->pg = page;
 780                 iov_iter_advance(cs->iter, err);
 781         }
 782
 783         return lock_request(cs->req);
 784 }
 785
 786 /* Do as much copy to/from userspace buffer as we can */
 787 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 788 {
 789         unsigned ncpy = min(*size, cs->len);
 790         if (val) {
 791                 void *pgaddr = kmap_atomic(cs->pg);
 792                 void *buf = pgaddr + cs->offset;
 793
 794                 if (cs->write)
 795                         memcpy(buf, *val, ncpy);
 796                 else
 797                         memcpy(*val, buf, ncpy);
 798
 799                 kunmap_atomic(pgaddr);
 800                 *val += ncpy;
 801         }
 802         *size -= ncpy;
 803         cs->len -= ncpy;
 804         cs->offset += ncpy;
 805         return ncpy;
 806 }
 807
 808 static int fuse_check_page(struct page *page)
 809 {
 810         if (page_mapcount(page) ||
 811             page->mapping != NULL ||
 812             page_count(page) != 1 ||
 813             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 814              ~(1 << PG_locked |
 815                1 << PG_referenced |
 816                1 << PG_uptodate |
 817                1 << PG_lru |
 818                1 << PG_active |
 819                1 << PG_reclaim))) {
 820                 printk(KERN_WARNING "fuse: trying to steal weird page\n");
 821                 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);
 822                 return 1;
 823         }
 824         return 0;
 825 }
 826
 827 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 828 {
 829         int err;
 830         struct page *oldpage = *pagep;
 831         struct page *newpage;
 832         struct pipe_buffer *buf = cs->pipebufs;
 833
 834         err = unlock_request(cs->req);
 835         if (err)
 836                 return err;
 837
 838         fuse_copy_finish(cs);
 839
 840         err = pipe_buf_confirm(cs->pipe, buf);
 841         if (err)
 842                 return err;
 843
 844         BUG_ON(!cs->nr_segs);
 845         cs->currbuf = buf;
 846         cs->len = buf->len;
 847         cs->pipebufs++;
 848         cs->nr_segs--;
 849
 850         if (cs->len != PAGE_SIZE)
 851                 goto out_fallback;
 852
 853         if (pipe_buf_steal(cs->pipe, buf) != 0)
 854                 goto out_fallback;
 855
 856         newpage = buf->page;
 857
 858         if (!PageUptodate(newpage))
 859                 SetPageUptodate(newpage);
 860
 861         ClearPageMappedToDisk(newpage);
 862
 863         if (fuse_check_page(newpage) != 0)
 864                 goto out_fallback_unlock;
 865
 866         /*
 867          * This is a new and locked page, it shouldn't be mapped or
 868          * have any special flags on it
 869          */
 870         if (WARN_ON(page_mapped(oldpage)))
 871                 goto out_fallback_unlock;
 872         if (WARN_ON(page_has_private(oldpage)))
 873                 goto out_fallback_unlock;
 874         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 875                 goto out_fallback_unlock;
 876         if (WARN_ON(PageMlocked(oldpage)))
 877                 goto out_fallback_unlock;
 878
 879         err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 880         if (err) {
 881                 unlock_page(newpage);
 882                 return err;
 883         }
 884
 885         get_page(newpage);
 886
 887         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 888                 lru_cache_add_file(newpage);
 889
 890         err = 0;
 891         spin_lock(&cs->req->waitq.lock);
 892         if (test_bit(FR_ABORTED, &cs->req->flags))
 893                 err = -ENOENT;
 894         else
 895                 *pagep = newpage;
 896         spin_unlock(&cs->req->waitq.lock);
 897
 898         if (err) {
 899                 unlock_page(newpage);
 900                 put_page(newpage);
 901                 return err;
 902         }
 903
 904         unlock_page(oldpage);
 905         put_page(oldpage);
 906         cs->len = 0;
 907
 908         return 0;
 909
 910 out_fallback_unlock:
 911         unlock_page(newpage);
 912 out_fallback:
 913         cs->pg = buf->page;
 914         cs->offset = buf->offset;
 915
 916         err = lock_request(cs->req);
 917         if (err)
 918                 return err;
 919
 920         return 1;
 921 }
 922
 923 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 924                          unsigned offset, unsigned count)
 925 {
 926         struct pipe_buffer *buf;
 927         int err;
 928
 929         if (cs->nr_segs == cs->pipe->buffers)
 930                 return -EIO;
 931
 932         err = unlock_request(cs->req);
 933         if (err)
 934                 return err;
 935
 936         fuse_copy_finish(cs);
 937
 938         buf = cs->pipebufs;
 939         get_page(page);
 940         buf->page = page;
 941         buf->offset = offset;
 942         buf->len = count;
 943
 944         cs->pipebufs++;
 945         cs->nr_segs++;
 946         cs->len = 0;
 947
 948         return 0;
 949 }
 950
 951 /*
 952  * Copy a page in the request to/from the userspace buffer.  Must be
 953  * done atomically
 954  */
 955 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 956                           unsigned offset, unsigned count, int zeroing)
 957 {
 958         int err;
 959         struct page *page = *pagep;
 960
 961         if (page && zeroing && count < PAGE_SIZE)
 962                 clear_highpage(page);
 963
 964         while (count) {
 965                 if (cs->write && cs->pipebufs && page) {
 966                         return fuse_ref_page(cs, page, offset, count);
 967                 } else if (!cs->len) {
 968                         if (cs->move_pages && page &&
 969                             offset == 0 && count == PAGE_SIZE) {
 970                                 err = fuse_try_move_page(cs, pagep);
 971                                 if (err <= 0)
 972                                         return err;
 973                         } else {
 974                                 err = fuse_copy_fill(cs);
 975                                 if (err)
 976                                         return err;
 977                         }
 978                 }
 979                 if (page) {
 980                         void *mapaddr = kmap_atomic(page);
 981                         void *buf = mapaddr + offset;
 982                         offset += fuse_copy_do(cs, &buf, &count);
 983                         kunmap_atomic(mapaddr);
 984                 } else
 985                         offset += fuse_copy_do(cs, NULL, &count);
 986         }
 987         if (page && !cs->write)
 988                 flush_dcache_page(page);
 989         return 0;
 990 }
 991
 992 /* Copy pages in the request to/from userspace buffer */
 993 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 994                            int zeroing)
 995 {
 996         unsigned i;
 997         struct fuse_req *req = cs->req;
 998
 999         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1000                 int err;
1001                 unsigned offset = req->page_descs[i].offset;
1002                 unsigned count = min(nbytes, req->page_descs[i].length);
1003
1004                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1005                                      zeroing);
1006                 if (err)
1007                         return err;
1008
1009                 nbytes -= count;
1010         }
1011         return 0;
1012 }
1013
1014 /* Copy a single argument in the request to/from userspace buffer */
1015 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1016 {
1017         while (size) {
1018                 if (!cs->len) {
1019                         int err = fuse_copy_fill(cs);
1020                         if (err)
1021                                 return err;
1022                 }
1023                 fuse_copy_do(cs, &val, &size);
1024         }
1025         return 0;
1026 }
1027
1028 /* Copy request arguments to/from userspace buffer */
1029 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1030                           unsigned argpages, struct fuse_arg *args,
1031                           int zeroing)
1032 {
1033         int err = 0;
1034         unsigned i;
1035
1036         for (i = 0; !err && i < numargs; i++)  {
1037                 struct fuse_arg *arg = &args[i];
1038                 if (i == numargs - 1 && argpages)
1039                         err = fuse_copy_pages(cs, arg->size, zeroing);
1040                 else
1041                         err = fuse_copy_one(cs, arg->value, arg->size);
1042         }
1043         return err;
1044 }
1045
1046 static int forget_pending(struct fuse_iqueue *fiq)
1047 {
1048         return fiq->forget_list_head.next != NULL;
1049 }
1050
1051 static int request_pending(struct fuse_iqueue *fiq)
1052 {
1053         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1054                 forget_pending(fiq);
1055 }
1056
1057 /*
1058  * Transfer an interrupt request to userspace
1059  *
1060  * Unlike other requests this is assembled on demand, without a need
1061  * to allocate a separate fuse_req structure.
1062  *
1063  * Called with fiq->waitq.lock held, releases it
1064  */
1065 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1066                                struct fuse_copy_state *cs,
1067                                size_t nbytes, struct fuse_req *req)
1068 __releases(fiq->waitq.lock)
1069 {
1070         struct fuse_in_header ih;
1071         struct fuse_interrupt_in arg;
1072         unsigned reqsize = sizeof(ih) + sizeof(arg);
1073         int err;
1074
1075         list_del_init(&req->intr_entry);
1076         req->intr_unique = fuse_get_unique(fiq);
1077         memset(&ih, 0, sizeof(ih));
1078         memset(&arg, 0, sizeof(arg));
1079         ih.len = reqsize;
1080         ih.opcode = FUSE_INTERRUPT;
1081         ih.unique = req->intr_unique;
1082         arg.unique = req->in.h.unique;
1083
1084         spin_unlock(&fiq->waitq.lock);
1085         if (nbytes < reqsize)
1086                 return -EINVAL;
1087
1088         err = fuse_copy_one(cs, &ih, sizeof(ih));
1089         if (!err)
1090                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1091         fuse_copy_finish(cs);
1092
1093         return err ? err : reqsize;
1094 }
1095
1096 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1097                                                unsigned max,
1098                                                unsigned *countp)
1099 {
1100         struct fuse_forget_link *head = fiq->forget_list_head.next;
1101         struct fuse_forget_link **newhead = &head;
1102         unsigned count;
1103
1104         for (count = 0; *newhead != NULL && count < max; count++)
1105                 newhead = &(*newhead)->next;
1106
1107         fiq->forget_list_head.next = *newhead;
1108         *newhead = NULL;
1109         if (fiq->forget_list_head.next == NULL)
1110                 fiq->forget_list_tail = &fiq->forget_list_head;
1111
1112         if (countp != NULL)
1113                 *countp = count;
1114
1115         return head;
1116 }
1117
1118 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1119                                    struct fuse_copy_state *cs,
1120                                    size_t nbytes)
1121 __releases(fiq->waitq.lock)
1122 {
1123         int err;
1124         struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1125         struct fuse_forget_in arg = {
1126                 .nlookup = forget->forget_one.nlookup,
1127         };
1128         struct fuse_in_header ih = {
1129                 .opcode = FUSE_FORGET,
1130                 .nodeid = forget->forget_one.nodeid,
1131                 .unique = fuse_get_unique(fiq),
1132                 .len = sizeof(ih) + sizeof(arg),
1133         };
1134
1135         spin_unlock(&fiq->waitq.lock);
1136         kfree(forget);
1137         if (nbytes < ih.len)
1138                 return -EINVAL;
1139
1140         err = fuse_copy_one(cs, &ih, sizeof(ih));
1141         if (!err)
1142                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1143         fuse_copy_finish(cs);
1144
1145         if (err)
1146                 return err;
1147
1148         return ih.len;
1149 }
1150
1151 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1152                                    struct fuse_copy_state *cs, size_t nbytes)
1153 __releases(fiq->waitq.lock)
1154 {
1155         int err;
1156         unsigned max_forgets;
1157         unsigned count;
1158         struct fuse_forget_link *head;
1159         struct fuse_batch_forget_in arg = { .count = 0 };
1160         struct fuse_in_header ih = {
1161                 .opcode = FUSE_BATCH_FORGET,
1162                 .unique = fuse_get_unique(fiq),
1163                 .len = sizeof(ih) + sizeof(arg),
1164         };
1165
1166         if (nbytes < ih.len) {
1167                 spin_unlock(&fiq->waitq.lock);
1168                 return -EINVAL;
1169         }
1170
1171         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1172         head = dequeue_forget(fiq, max_forgets, &count);
1173         spin_unlock(&fiq->waitq.lock);
1174
1175         arg.count = count;
1176         ih.len += count * sizeof(struct fuse_forget_one);
1177         err = fuse_copy_one(cs, &ih, sizeof(ih));
1178         if (!err)
1179                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1180
1181         while (head) {
1182                 struct fuse_forget_link *forget = head;
1183
1184                 if (!err) {
1185                         err = fuse_copy_one(cs, &forget->forget_one,
1186                                             sizeof(forget->forget_one));
1187                 }
1188                 head = forget->next;
1189                 kfree(forget);
1190         }
1191
1192         fuse_copy_finish(cs);
1193
1194         if (err)
1195                 return err;
1196
1197         return ih.len;
1198 }
1199
1200 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1201                             struct fuse_copy_state *cs,
1202                             size_t nbytes)
1203 __releases(fiq->waitq.lock)
1204 {
1205         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1206                 return fuse_read_single_forget(fiq, cs, nbytes);
1207         else
1208                 return fuse_read_batch_forget(fiq, cs, nbytes);
1209 }
1210
1211 /*
1212  * Read a single request into the userspace filesystem's buffer.  This
1213  * function waits until a request is available, then removes it from
1214  * the pending list and copies request data to userspace buffer.  If
1215  * no reply is needed (FORGET) or request has been aborted or there
1216  * was an error during the copying then it's finished by calling
1217  * request_end().  Otherwise add it to the processing list, and set
1218  * the 'sent' flag.
1219  */
1220 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1221                                 struct fuse_copy_state *cs, size_t nbytes)
1222 {
1223         ssize_t err;
1224         struct fuse_conn *fc = fud->fc;
1225         struct fuse_iqueue *fiq = &fc->iq;
1226         struct fuse_pqueue *fpq = &fud->pq;
1227         struct fuse_req *req;
1228         struct fuse_in *in;
1229         unsigned reqsize;
1230
1231  restart:
1232         spin_lock(&fiq->waitq.lock);
1233         err = -EAGAIN;
1234         if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1235             !request_pending(fiq))
1236                 goto err_unlock;
1237
1238         err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1239                                 !fiq->connected || request_pending(fiq));
1240         if (err)
1241                 goto err_unlock;
1242
1243         if (!fiq->connected) {
1244                 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1245                 goto err_unlock;
1246         }
1247
1248         if (!list_empty(&fiq->interrupts)) {
1249                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1250                                  intr_entry);
1251                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1252         }
1253
1254         if (forget_pending(fiq)) {
1255                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1256                         return fuse_read_forget(fc, fiq, cs, nbytes);
1257
1258                 if (fiq->forget_batch <= -8)
1259                         fiq->forget_batch = 16;
1260         }
1261
1262         req = list_entry(fiq->pending.next, struct fuse_req, list);
1263         clear_bit(FR_PENDING, &req->flags);
1264         list_del_init(&req->list);
1265         spin_unlock(&fiq->waitq.lock);
1266
1267         in = &req->in;
1268         reqsize = in->h.len;
1269
1270         /* If request is too large, reply with an error and restart the read */
1271         if (nbytes < reqsize) {
1272                 req->out.h.error = -EIO;
1273                 /* SETXATTR is special, since it may contain too large data */
1274                 if (in->h.opcode == FUSE_SETXATTR)
1275                         req->out.h.error = -E2BIG;
1276                 request_end(fc, req);
1277                 goto restart;
1278         }
1279         spin_lock(&fpq->lock);
1280         list_add(&req->list, &fpq->io);
1281         spin_unlock(&fpq->lock);
1282         cs->req = req;
1283         err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1284         if (!err)
1285                 err = fuse_copy_args(cs, in->numargs, in->argpages,
1286                                      (struct fuse_arg *) in->args, 0);
1287         fuse_copy_finish(cs);
1288         spin_lock(&fpq->lock);
1289         clear_bit(FR_LOCKED, &req->flags);
1290         if (!fpq->connected) {
1291                 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1292                 goto out_end;
1293         }
1294         if (err) {
1295                 req->out.h.error = -EIO;
1296                 goto out_end;
1297         }
1298         if (!test_bit(FR_ISREPLY, &req->flags)) {
1299                 err = reqsize;
1300                 goto out_end;
1301         }
1302         list_move_tail(&req->list, &fpq->processing);
1303         spin_unlock(&fpq->lock);
1304         set_bit(FR_SENT, &req->flags);
1305         /* matches barrier in request_wait_answer() */
1306         smp_mb__after_atomic();
1307         if (test_bit(FR_INTERRUPTED, &req->flags))
1308                 queue_interrupt(fiq, req);
1309
1310         return reqsize;
1311
1312 out_end:
1313         if (!test_bit(FR_PRIVATE, &req->flags))
1314                 list_del_init(&req->list);
1315         spin_unlock(&fpq->lock);
1316         request_end(fc, req);
1317         return err;
1318
1319  err_unlock:
1320         spin_unlock(&fiq->waitq.lock);
1321         return err;
1322 }
1323
1324 static int fuse_dev_open(struct inode *inode, struct file *file)
1325 {
1326         /*
1327          * The fuse device's file's private_data is used to hold
1328          * the fuse_conn(ection) when it is mounted, and is used to
1329          * keep track of whether the file has been mounted already.
1330          */
1331         file->private_data = NULL;
1332         return 0;
1333 }
1334
1335 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1336 {
1337         struct fuse_copy_state cs;
1338         struct file *file = iocb->ki_filp;
1339         struct fuse_dev *fud = fuse_get_dev(file);
1340
1341         if (!fud)
1342                 return -EPERM;
1343
1344         if (!iter_is_iovec(to))
1345                 return -EINVAL;
1346
1347         fuse_copy_init(&cs, 1, to);
1348
1349         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1350 }
1351
1352 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1353                                     struct pipe_inode_info *pipe,
1354                                     size_t len, unsigned int flags)
1355 {
1356         int total, ret;
1357         int page_nr = 0;
1358         struct pipe_buffer *bufs;
1359         struct fuse_copy_state cs;
1360         struct fuse_dev *fud = fuse_get_dev(in);
1361
1362         if (!fud)
1363                 return -EPERM;
1364
1365         bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1366                              GFP_KERNEL);
1367         if (!bufs)
1368                 return -ENOMEM;
1369
1370         fuse_copy_init(&cs, 1, NULL);
1371         cs.pipebufs = bufs;
1372         cs.pipe = pipe;
1373         ret = fuse_dev_do_read(fud, in, &cs, len);
1374         if (ret < 0)
1375                 goto out;
1376
1377         if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1378                 ret = -EIO;
1379                 goto out;
1380         }
1381
1382         for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1383                 /*
1384                  * Need to be careful about this.  Having buf->ops in module
1385                  * code can Oops if the buffer persists after module unload.
1386                  */
1387                 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1388                 bufs[page_nr].flags = 0;
1389                 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1390                 if (unlikely(ret < 0))
1391                         break;
1392         }
1393         if (total)
1394                 ret = total;
1395 out:
1396         for (; page_nr < cs.nr_segs; page_nr++)
1397                 put_page(bufs[page_nr].page);
1398
1399         kfree(bufs);
1400         return ret;
1401 }
1402
1403 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1404                             struct fuse_copy_state *cs)
1405 {
1406         struct fuse_notify_poll_wakeup_out outarg;
1407         int err = -EINVAL;
1408
1409         if (size != sizeof(outarg))
1410                 goto err;
1411
1412         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1413         if (err)
1414                 goto err;
1415
1416         fuse_copy_finish(cs);
1417         return fuse_notify_poll_wakeup(fc, &outarg);
1418
1419 err:
1420         fuse_copy_finish(cs);
1421         return err;
1422 }
1423
1424 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1425                                    struct fuse_copy_state *cs)
1426 {
1427         struct fuse_notify_inval_inode_out outarg;
1428         int err = -EINVAL;
1429
1430         if (size != sizeof(outarg))
1431                 goto err;
1432
1433         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1434         if (err)
1435                 goto err;
1436         fuse_copy_finish(cs);
1437
1438         down_read(&fc->killsb);
1439         err = -ENOENT;
1440         if (fc->sb) {
1441                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1442                                                outarg.off, outarg.len);
1443         }
1444         up_read(&fc->killsb);
1445         return err;
1446
1447 err:
1448         fuse_copy_finish(cs);
1449         return err;
1450 }
1451
1452 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1453                                    struct fuse_copy_state *cs)
1454 {
1455         struct fuse_notify_inval_entry_out outarg;
1456         int err = -ENOMEM;
1457         char *buf;
1458         struct qstr name;
1459
1460         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1461         if (!buf)
1462                 goto err;
1463
1464         err = -EINVAL;
1465         if (size < sizeof(outarg))
1466                 goto err;
1467
1468         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1469         if (err)
1470                 goto err;
1471
1472         err = -ENAMETOOLONG;
1473         if (outarg.namelen > FUSE_NAME_MAX)
1474                 goto err;
1475
1476         err = -EINVAL;
1477         if (size != sizeof(outarg) + outarg.namelen + 1)
1478                 goto err;
1479
1480         name.name = buf;
1481         name.len = outarg.namelen;
1482         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1483         if (err)
1484                 goto err;
1485         fuse_copy_finish(cs);
1486         buf[outarg.namelen] = 0;
1487
1488         down_read(&fc->killsb);
1489         err = -ENOENT;
1490         if (fc->sb)
1491                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1492         up_read(&fc->killsb);
1493         kfree(buf);
1494         return err;
1495
1496 err:
1497         kfree(buf);
1498         fuse_copy_finish(cs);
1499         return err;
1500 }
1501
1502 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1503                               struct fuse_copy_state *cs)
1504 {
1505         struct fuse_notify_delete_out outarg;
1506         int err = -ENOMEM;
1507         char *buf;
1508         struct qstr name;
1509
1510         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1511         if (!buf)
1512                 goto err;
1513
1514         err = -EINVAL;
1515         if (size < sizeof(outarg))
1516                 goto err;
1517
1518         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1519         if (err)
1520                 goto err;
1521
1522         err = -ENAMETOOLONG;
1523         if (outarg.namelen > FUSE_NAME_MAX)
1524                 goto err;
1525
1526         err = -EINVAL;
1527         if (size != sizeof(outarg) + outarg.namelen + 1)
1528                 goto err;
1529
1530         name.name = buf;
1531         name.len = outarg.namelen;
1532         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1533         if (err)
1534                 goto err;
1535         fuse_copy_finish(cs);
1536         buf[outarg.namelen] = 0;
1537
1538         down_read(&fc->killsb);
1539         err = -ENOENT;
1540         if (fc->sb)
1541                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1542                                                outarg.child, &name);
1543         up_read(&fc->killsb);
1544         kfree(buf);
1545         return err;
1546
1547 err:
1548         kfree(buf);
1549         fuse_copy_finish(cs);
1550         return err;
1551 }
1552
1553 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1554                              struct fuse_copy_state *cs)
1555 {
1556         struct fuse_notify_store_out outarg;
1557         struct inode *inode;
1558         struct address_space *mapping;
1559         u64 nodeid;
1560         int err;
1561         pgoff_t index;
1562         unsigned int offset;
1563         unsigned int num;
1564         loff_t file_size;
1565         loff_t end;
1566
1567         err = -EINVAL;
1568         if (size < sizeof(outarg))
1569                 goto out_finish;
1570
1571         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1572         if (err)
1573                 goto out_finish;
1574
1575         err = -EINVAL;
1576         if (size - sizeof(outarg) != outarg.size)
1577                 goto out_finish;
1578
1579         nodeid = outarg.nodeid;
1580
1581         down_read(&fc->killsb);
1582
1583         err = -ENOENT;
1584         if (!fc->sb)
1585                 goto out_up_killsb;
1586
1587         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1588         if (!inode)
1589                 goto out_up_killsb;
1590
1591         mapping = inode->i_mapping;
1592         index = outarg.offset >> PAGE_SHIFT;
1593         offset = outarg.offset & ~PAGE_MASK;
1594         file_size = i_size_read(inode);
1595         end = outarg.offset + outarg.size;
1596         if (end > file_size) {
1597                 file_size = end;
1598                 fuse_write_update_size(inode, file_size);
1599         }
1600
1601         num = outarg.size;
1602         while (num) {
1603                 struct page *page;
1604                 unsigned int this_num;
1605
1606                 err = -ENOMEM;
1607                 page = find_or_create_page(mapping, index,
1608                                            mapping_gfp_mask(mapping));
1609                 if (!page)
1610                         goto out_iput;
1611
1612                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1613                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1614                 if (!err && offset == 0 &&
1615                     (this_num == PAGE_SIZE || file_size == end))
1616                         SetPageUptodate(page);
1617                 unlock_page(page);
1618                 put_page(page);
1619
1620                 if (err)
1621                         goto out_iput;
1622
1623                 num -= this_num;
1624                 offset = 0;
1625                 index++;
1626         }
1627
1628         err = 0;
1629
1630 out_iput:
1631         iput(inode);
1632 out_up_killsb:
1633         up_read(&fc->killsb);
1634 out_finish:
1635         fuse_copy_finish(cs);
1636         return err;
1637 }
1638
1639 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1640 {
1641         release_pages(req->pages, req->num_pages);
1642 }
1643
1644 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1645                          struct fuse_notify_retrieve_out *outarg)
1646 {
1647         int err;
1648         struct address_space *mapping = inode->i_mapping;
1649         struct fuse_req *req;
1650         pgoff_t index;
1651         loff_t file_size;
1652         unsigned int num;
1653         unsigned int offset;
1654         size_t total_len = 0;
1655         int num_pages;
1656
1657         offset = outarg->offset & ~PAGE_MASK;
1658         file_size = i_size_read(inode);
1659
1660         num = outarg->size;
1661         if (outarg->offset > file_size)
1662                 num = 0;
1663         else if (outarg->offset + num > file_size)
1664                 num = file_size - outarg->offset;
1665
1666         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1667         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1668
1669         req = fuse_get_req(fc, num_pages);
1670         if (IS_ERR(req))
1671                 return PTR_ERR(req);
1672
1673         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1674         req->in.h.nodeid = outarg->nodeid;
1675         req->in.numargs = 2;
1676         req->in.argpages = 1;
1677         req->page_descs[0].offset = offset;
1678         req->end = fuse_retrieve_end;
1679
1680         index = outarg->offset >> PAGE_SHIFT;
1681
1682         while (num && req->num_pages < num_pages) {
1683                 struct page *page;
1684                 unsigned int this_num;
1685
1686                 page = find_get_page(mapping, index);
1687                 if (!page)
1688                         break;
1689
1690                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1691                 req->pages[req->num_pages] = page;
1692                 req->page_descs[req->num_pages].length = this_num;
1693                 req->num_pages++;
1694
1695                 offset = 0;
1696                 num -= this_num;
1697                 total_len += this_num;
1698                 index++;
1699         }
1700         req->misc.retrieve_in.offset = outarg->offset;
1701         req->misc.retrieve_in.size = total_len;
1702         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1703         req->in.args[0].value = &req->misc.retrieve_in;
1704         req->in.args[1].size = total_len;
1705
1706         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1707         if (err)
1708                 fuse_retrieve_end(fc, req);
1709
1710         return err;
1711 }
1712
1713 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1714                                 struct fuse_copy_state *cs)
1715 {
1716         struct fuse_notify_retrieve_out outarg;
1717         struct inode *inode;
1718         int err;
1719
1720         err = -EINVAL;
1721         if (size != sizeof(outarg))
1722                 goto copy_finish;
1723
1724         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1725         if (err)
1726                 goto copy_finish;
1727
1728         fuse_copy_finish(cs);
1729
1730         down_read(&fc->killsb);
1731         err = -ENOENT;
1732         if (fc->sb) {
1733                 u64 nodeid = outarg.nodeid;
1734
1735                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1736                 if (inode) {
1737                         err = fuse_retrieve(fc, inode, &outarg);
1738                         iput(inode);
1739                 }
1740         }
1741         up_read(&fc->killsb);
1742
1743         return err;
1744
1745 copy_finish:
1746         fuse_copy_finish(cs);
1747         return err;
1748 }
1749
1750 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1751                        unsigned int size, struct fuse_copy_state *cs)
1752 {
1753         /* Don't try to move pages (yet) */
1754         cs->move_pages = 0;
1755
1756         switch (code) {
1757         case FUSE_NOTIFY_POLL:
1758                 return fuse_notify_poll(fc, size, cs);
1759
1760         case FUSE_NOTIFY_INVAL_INODE:
1761                 return fuse_notify_inval_inode(fc, size, cs);
1762
1763         case FUSE_NOTIFY_INVAL_ENTRY:
1764                 return fuse_notify_inval_entry(fc, size, cs);
1765
1766         case FUSE_NOTIFY_STORE:
1767                 return fuse_notify_store(fc, size, cs);
1768
1769         case FUSE_NOTIFY_RETRIEVE:
1770                 return fuse_notify_retrieve(fc, size, cs);
1771
1772         case FUSE_NOTIFY_DELETE:
1773                 return fuse_notify_delete(fc, size, cs);
1774
1775         default:
1776                 fuse_copy_finish(cs);
1777                 return -EINVAL;
1778         }
1779 }
1780
1781 /* Look up request on processing list by unique ID */
1782 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1783 {
1784         struct fuse_req *req;
1785
1786         list_for_each_entry(req, &fpq->processing, list) {
1787                 if (req->in.h.unique == unique || req->intr_unique == unique)
1788                         return req;
1789         }
1790         return NULL;
1791 }
1792
1793 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1794                          unsigned nbytes)
1795 {
1796         unsigned reqsize = sizeof(struct fuse_out_header);
1797
1798         if (out->h.error)
1799                 return nbytes != reqsize ? -EINVAL : 0;
1800
1801         reqsize += len_args(out->numargs, out->args);
1802
1803         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1804                 return -EINVAL;
1805         else if (reqsize > nbytes) {
1806                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1807                 unsigned diffsize = reqsize - nbytes;
1808                 if (diffsize > lastarg->size)
1809                         return -EINVAL;
1810                 lastarg->size -= diffsize;
1811         }
1812         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1813                               out->page_zeroing);
1814 }
1815
1816 /*
1817  * Write a single reply to a request.  First the header is copied from
1818  * the write buffer.  The request is then searched on the processing
1819  * list by the unique ID found in the header.  If found, then remove
1820  * it from the list and copy the rest of the buffer to the request.
1821  * The request is finished by calling request_end()
1822  */
1823 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1824                                  struct fuse_copy_state *cs, size_t nbytes)
1825 {
1826         int err;
1827         struct fuse_conn *fc = fud->fc;
1828         struct fuse_pqueue *fpq = &fud->pq;
1829         struct fuse_req *req;
1830         struct fuse_out_header oh;
1831
1832         if (nbytes < sizeof(struct fuse_out_header))
1833                 return -EINVAL;
1834
1835         err = fuse_copy_one(cs, &oh, sizeof(oh));
1836         if (err)
1837                 goto err_finish;
1838
1839         err = -EINVAL;
1840         if (oh.len != nbytes)
1841                 goto err_finish;
1842
1843         /*
1844          * Zero oh.unique indicates unsolicited notification message
1845          * and error contains notification code.
1846          */
1847         if (!oh.unique) {
1848                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1849                 return err ? err : nbytes;
1850         }
1851
1852         err = -EINVAL;
1853         if (oh.error <= -1000 || oh.error > 0)
1854                 goto err_finish;
1855
1856         spin_lock(&fpq->lock);
1857         err = -ENOENT;
1858         if (!fpq->connected)
1859                 goto err_unlock_pq;
1860
1861         req = request_find(fpq, oh.unique);
1862         if (!req)
1863                 goto err_unlock_pq;
1864
1865         /* Is it an interrupt reply? */
1866         if (req->intr_unique == oh.unique) {
1867                 spin_unlock(&fpq->lock);
1868
1869                 err = -EINVAL;
1870                 if (nbytes != sizeof(struct fuse_out_header))
1871                         goto err_finish;
1872
1873                 if (oh.error == -ENOSYS)
1874                         fc->no_interrupt = 1;
1875                 else if (oh.error == -EAGAIN)
1876                         queue_interrupt(&fc->iq, req);
1877
1878                 fuse_copy_finish(cs);
1879                 return nbytes;
1880         }
1881
1882         clear_bit(FR_SENT, &req->flags);
1883         list_move(&req->list, &fpq->io);
1884         req->out.h = oh;
1885         set_bit(FR_LOCKED, &req->flags);
1886         spin_unlock(&fpq->lock);
1887         cs->req = req;
1888         if (!req->out.page_replace)
1889                 cs->move_pages = 0;
1890
1891         err = copy_out_args(cs, &req->out, nbytes);
1892         fuse_copy_finish(cs);
1893
1894         spin_lock(&fpq->lock);
1895         clear_bit(FR_LOCKED, &req->flags);
1896         if (!fpq->connected)
1897                 err = -ENOENT;
1898         else if (err)
1899                 req->out.h.error = -EIO;
1900         if (!test_bit(FR_PRIVATE, &req->flags))
1901                 list_del_init(&req->list);
1902         spin_unlock(&fpq->lock);
1903
1904         request_end(fc, req);
1905
1906         return err ? err : nbytes;
1907
1908  err_unlock_pq:
1909         spin_unlock(&fpq->lock);
1910  err_finish:
1911         fuse_copy_finish(cs);
1912         return err;
1913 }
1914
1915 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1916 {
1917         struct fuse_copy_state cs;
1918         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1919
1920         if (!fud)
1921                 return -EPERM;
1922
1923         if (!iter_is_iovec(from))
1924                 return -EINVAL;
1925
1926         fuse_copy_init(&cs, 0, from);
1927
1928         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1929 }
1930
1931 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1932                                      struct file *out, loff_t *ppos,
1933                                      size_t len, unsigned int flags)
1934 {
1935         unsigned nbuf;
1936         unsigned idx;
1937         struct pipe_buffer *bufs;
1938         struct fuse_copy_state cs;
1939         struct fuse_dev *fud;
1940         size_t rem;
1941         ssize_t ret;
1942
1943         fud = fuse_get_dev(out);
1944         if (!fud)
1945                 return -EPERM;
1946
1947         bufs = kmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1948                              GFP_KERNEL);
1949         if (!bufs)
1950                 return -ENOMEM;
1951
1952         pipe_lock(pipe);
1953         nbuf = 0;
1954         rem = 0;
1955         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1956                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1957
1958         ret = -EINVAL;
1959         if (rem < len) {
1960                 pipe_unlock(pipe);
1961                 goto out;
1962         }
1963
1964         rem = len;
1965         while (rem) {
1966                 struct pipe_buffer *ibuf;
1967                 struct pipe_buffer *obuf;
1968
1969                 BUG_ON(nbuf >= pipe->buffers);
1970                 BUG_ON(!pipe->nrbufs);
1971                 ibuf = &pipe->bufs[pipe->curbuf];
1972                 obuf = &bufs[nbuf];
1973
1974                 if (rem >= ibuf->len) {
1975                         *obuf = *ibuf;
1976                         ibuf->ops = NULL;
1977                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1978                         pipe->nrbufs--;
1979                 } else {
1980                         pipe_buf_get(pipe, ibuf);
1981                         *obuf = *ibuf;
1982                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1983                         obuf->len = rem;
1984                         ibuf->offset += obuf->len;
1985                         ibuf->len -= obuf->len;
1986                 }
1987                 nbuf++;
1988                 rem -= obuf->len;
1989         }
1990         pipe_unlock(pipe);
1991
1992         fuse_copy_init(&cs, 0, NULL);
1993         cs.pipebufs = bufs;
1994         cs.nr_segs = nbuf;
1995         cs.pipe = pipe;
1996
1997         if (flags & SPLICE_F_MOVE)
1998                 cs.move_pages = 1;
1999
2000         ret = fuse_dev_do_write(fud, &cs, len);
2001
2002         for (idx = 0; idx < nbuf; idx++)
2003                 pipe_buf_release(pipe, &bufs[idx]);
2004
2005 out:
2006         kfree(bufs);
2007         return ret;
2008 }
2009
2010 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2011 {
2012         __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2013         struct fuse_iqueue *fiq;
2014         struct fuse_dev *fud = fuse_get_dev(file);
2015
2016         if (!fud)
2017                 return EPOLLERR;
2018
2019         fiq = &fud->fc->iq;
2020         poll_wait(file, &fiq->waitq, wait);
2021
2022         spin_lock(&fiq->waitq.lock);
2023         if (!fiq->connected)
2024                 mask = EPOLLERR;
2025         else if (request_pending(fiq))
2026                 mask |= EPOLLIN | EPOLLRDNORM;
2027         spin_unlock(&fiq->waitq.lock);
2028
2029         return mask;
2030 }
2031
2032 /*
2033  * Abort all requests on the given list (pending or processing)
2034  *
2035  * This function releases and reacquires fc->lock
2036  */
2037 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2038 {
2039         while (!list_empty(head)) {
2040                 struct fuse_req *req;
2041                 req = list_entry(head->next, struct fuse_req, list);
2042                 req->out.h.error = -ECONNABORTED;
2043                 clear_bit(FR_SENT, &req->flags);
2044                 list_del_init(&req->list);
2045                 request_end(fc, req);
2046         }
2047 }
2048
2049 static void end_polls(struct fuse_conn *fc)
2050 {
2051         struct rb_node *p;
2052
2053         p = rb_first(&fc->polled_files);
2054
2055         while (p) {
2056                 struct fuse_file *ff;
2057                 ff = rb_entry(p, struct fuse_file, polled_node);
2058                 wake_up_interruptible_all(&ff->poll_wait);
2059
2060                 p = rb_next(p);
2061         }
2062 }
2063
2064 /*
2065  * Abort all requests.
2066  *
2067  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2068  * filesystem.
2069  *
2070  * The same effect is usually achievable through killing the filesystem daemon
2071  * and all users of the filesystem.  The exception is the combination of an
2072  * asynchronous request and the tricky deadlock (see
2073  * Documentation/filesystems/fuse.txt).
2074  *
2075  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2076  * requests, they should be finished off immediately.  Locked requests will be
2077  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2078  * requests.  It is possible that some request will finish before we can.  This
2079  * is OK, the request will in that case be removed from the list before we touch
2080  * it.
2081  */
2082 void fuse_abort_conn(struct fuse_conn *fc, bool is_abort)
2083 {
2084         struct fuse_iqueue *fiq = &fc->iq;
2085
2086         spin_lock(&fc->lock);
2087         if (fc->connected) {
2088                 struct fuse_dev *fud;
2089                 struct fuse_req *req, *next;
2090                 LIST_HEAD(to_end1);
2091                 LIST_HEAD(to_end2);
2092
2093                 fc->connected = 0;
2094                 fc->blocked = 0;
2095                 fc->aborted = is_abort;
2096                 fuse_set_initialized(fc);
2097                 list_for_each_entry(fud, &fc->devices, entry) {
2098                         struct fuse_pqueue *fpq = &fud->pq;
2099
2100                         spin_lock(&fpq->lock);
2101                         fpq->connected = 0;
2102                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2103                                 req->out.h.error = -ECONNABORTED;
2104                                 spin_lock(&req->waitq.lock);
2105                                 set_bit(FR_ABORTED, &req->flags);
2106                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2107                                         set_bit(FR_PRIVATE, &req->flags);
2108                                         list_move(&req->list, &to_end1);
2109                                 }
2110                                 spin_unlock(&req->waitq.lock);
2111                         }
2112                         list_splice_init(&fpq->processing, &to_end2);
2113                         spin_unlock(&fpq->lock);
2114                 }
2115                 fc->max_background = UINT_MAX;
2116                 flush_bg_queue(fc);
2117
2118                 spin_lock(&fiq->waitq.lock);
2119                 fiq->connected = 0;
2120                 list_splice_init(&fiq->pending, &to_end2);
2121                 list_for_each_entry(req, &to_end2, list)
2122                         clear_bit(FR_PENDING, &req->flags);
2123                 while (forget_pending(fiq))
2124                         kfree(dequeue_forget(fiq, 1, NULL));
2125                 wake_up_all_locked(&fiq->waitq);
2126                 spin_unlock(&fiq->waitq.lock);
2127                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2128                 end_polls(fc);
2129                 wake_up_all(&fc->blocked_waitq);
2130                 spin_unlock(&fc->lock);
2131
2132                 while (!list_empty(&to_end1)) {
2133                         req = list_first_entry(&to_end1, struct fuse_req, list);
2134                         __fuse_get_request(req);
2135                         list_del_init(&req->list);
2136                         request_end(fc, req);
2137                 }
2138                 end_requests(fc, &to_end2);
2139         } else {
2140                 spin_unlock(&fc->lock);
2141         }
2142 }
2143 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2144
2145 int fuse_dev_release(struct inode *inode, struct file *file)
2146 {
2147         struct fuse_dev *fud = fuse_get_dev(file);
2148
2149         if (fud) {
2150                 struct fuse_conn *fc = fud->fc;
2151                 struct fuse_pqueue *fpq = &fud->pq;
2152
2153                 WARN_ON(!list_empty(&fpq->io));
2154                 end_requests(fc, &fpq->processing);
2155                 /* Are we the last open device? */
2156                 if (atomic_dec_and_test(&fc->dev_count)) {
2157                         WARN_ON(fc->iq.fasync != NULL);
2158                         fuse_abort_conn(fc, false);
2159                 }
2160                 fuse_dev_free(fud);
2161         }
2162         return 0;
2163 }
2164 EXPORT_SYMBOL_GPL(fuse_dev_release);
2165
2166 static int fuse_dev_fasync(int fd, struct file *file, int on)
2167 {
2168         struct fuse_dev *fud = fuse_get_dev(file);
2169
2170         if (!fud)
2171                 return -EPERM;
2172
2173         /* No locking - fasync_helper does its own locking */
2174         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2175 }
2176
2177 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2178 {
2179         struct fuse_dev *fud;
2180
2181         if (new->private_data)
2182                 return -EINVAL;
2183
2184         fud = fuse_dev_alloc(fc);
2185         if (!fud)
2186                 return -ENOMEM;
2187
2188         new->private_data = fud;
2189         atomic_inc(&fc->dev_count);
2190
2191         return 0;
2192 }
2193
2194 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2195                            unsigned long arg)
2196 {
2197         int err = -ENOTTY;
2198
2199         if (cmd == FUSE_DEV_IOC_CLONE) {
2200                 int oldfd;
2201
2202                 err = -EFAULT;
2203                 if (!get_user(oldfd, (__u32 __user *) arg)) {
2204                         struct file *old = fget(oldfd);
2205
2206                         err = -EINVAL;
2207                         if (old) {
2208                                 struct fuse_dev *fud = NULL;
2209
2210                                 /*
2211                                  * Check against file->f_op because CUSE
2212                                  * uses the same ioctl handler.
2213                                  */
2214                                 if (old->f_op == file->f_op &&
2215                                     old->f_cred->user_ns == file->f_cred->user_ns)
2216                                         fud = fuse_get_dev(old);
2217
2218                                 if (fud) {
2219                                         mutex_lock(&fuse_mutex);
2220                                         err = fuse_device_clone(fud->fc, file);
2221                                         mutex_unlock(&fuse_mutex);
2222                                 }
2223                                 fput(old);
2224                         }
2225                 }
2226         }
2227         return err;
2228 }
2229
2230 const struct file_operations fuse_dev_operations = {
2231         .owner          = THIS_MODULE,
2232         .open           = fuse_dev_open,
2233         .llseek         = no_llseek,
2234         .read_iter      = fuse_dev_read,
2235         .splice_read    = fuse_dev_splice_read,
2236         .write_iter     = fuse_dev_write,
2237         .splice_write   = fuse_dev_splice_write,
2238         .poll           = fuse_dev_poll,
2239         .release        = fuse_dev_release,
2240         .fasync         = fuse_dev_fasync,
2241         .unlocked_ioctl = fuse_dev_ioctl,
2242         .compat_ioctl   = fuse_dev_ioctl,
2243 };
2244 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2245
2246 static struct miscdevice fuse_miscdevice = {
2247         .minor = FUSE_MINOR,
2248         .name  = "fuse",
2249         .fops = &fuse_dev_operations,
2250 };
2251
2252 int __init fuse_dev_init(void)
2253 {
2254         int err = -ENOMEM;
2255         fuse_req_cachep = kmem_cache_create("fuse_request",
2256                                             sizeof(struct fuse_req),
2257                                             0, 0, NULL);
2258         if (!fuse_req_cachep)
2259                 goto out;
2260
2261         err = misc_register(&fuse_miscdevice);
2262         if (err)
2263                 goto out_cache_clean;
2264
2265         return 0;
2266
2267  out_cache_clean:
2268         kmem_cache_destroy(fuse_req_cachep);
2269  out:
2270         return err;
2271 }
2272
2273 void fuse_dev_cleanup(void)
2274 {
2275         misc_deregister(&fuse_miscdevice);
2276         kmem_cache_destroy(fuse_req_cachep);
2277 }