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/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
  23 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
  24 MODULE_ALIAS("devname:fuse");
  25
  26 static struct kmem_cache *fuse_req_cachep;
  27
  28 static struct fuse_dev *fuse_get_dev(struct file *file)
  29 {
  30         /*
  31          * Lockless access is OK, because file->private data is set
  32          * once during mount and is valid until the file is released.
  33          */
  34         return ACCESS_ONCE(file->private_data);
  35 }
  36
  37 static void fuse_request_init(struct fuse_req *req, struct page **pages,
  38                               struct fuse_page_desc *page_descs,
  39                               unsigned npages)
  40 {
  41         memset(req, 0, sizeof(*req));
  42         memset(pages, 0, sizeof(*pages) * npages);
  43         memset(page_descs, 0, sizeof(*page_descs) * npages);
  44         INIT_LIST_HEAD(&req->list);
  45         INIT_LIST_HEAD(&req->intr_entry);
  46         init_waitqueue_head(&req->waitq);
  47         atomic_set(&req->count, 1);
  48         req->pages = pages;
  49         req->page_descs = page_descs;
  50         req->max_pages = npages;
  51         __set_bit(FR_PENDING, &req->flags);
  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 void __fuse_get_request(struct fuse_req *req)
 103 {
 104         atomic_inc(&req->count);
 105 }
 106
 107 /* Must be called with > 1 refcount */
 108 static void __fuse_put_request(struct fuse_req *req)
 109 {
 110         BUG_ON(atomic_read(&req->count) < 2);
 111         atomic_dec(&req->count);
 112 }
 113
 114 static void fuse_req_init_context(struct fuse_req *req)
 115 {
 116         req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
 117         req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
 118         req->in.h.pid = current->pid;
 119 }
 120
 121 void fuse_set_initialized(struct fuse_conn *fc)
 122 {
 123         /* Make sure stores before this are seen on another CPU */
 124         smp_wmb();
 125         fc->initialized = 1;
 126 }
 127
 128 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 129 {
 130         return !fc->initialized || (for_background && fc->blocked);
 131 }
 132
 133 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
 134                                        bool for_background)
 135 {
 136         struct fuse_req *req;
 137         int err;
 138         atomic_inc(&fc->num_waiting);
 139
 140         if (fuse_block_alloc(fc, for_background)) {
 141                 err = -EINTR;
 142                 if (wait_event_killable_exclusive(fc->blocked_waitq,
 143                                 !fuse_block_alloc(fc, for_background)))
 144                         goto out;
 145         }
 146         /* Matches smp_wmb() in fuse_set_initialized() */
 147         smp_rmb();
 148
 149         err = -ENOTCONN;
 150         if (!fc->connected)
 151                 goto out;
 152
 153         err = -ECONNREFUSED;
 154         if (fc->conn_error)
 155                 goto out;
 156
 157         req = fuse_request_alloc(npages);
 158         err = -ENOMEM;
 159         if (!req) {
 160                 if (for_background)
 161                         wake_up(&fc->blocked_waitq);
 162                 goto out;
 163         }
 164
 165         fuse_req_init_context(req);
 166         __set_bit(FR_WAITING, &req->flags);
 167         if (for_background)
 168                 __set_bit(FR_BACKGROUND, &req->flags);
 169
 170         return req;
 171
 172  out:
 173         atomic_dec(&fc->num_waiting);
 174         return ERR_PTR(err);
 175 }
 176
 177 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
 178 {
 179         return __fuse_get_req(fc, npages, false);
 180 }
 181 EXPORT_SYMBOL_GPL(fuse_get_req);
 182
 183 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 184                                              unsigned npages)
 185 {
 186         return __fuse_get_req(fc, npages, true);
 187 }
 188 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
 189
 190 /*
 191  * Return request in fuse_file->reserved_req.  However that may
 192  * currently be in use.  If that is the case, wait for it to become
 193  * available.
 194  */
 195 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
 196                                          struct file *file)
 197 {
 198         struct fuse_req *req = NULL;
 199         struct fuse_file *ff = file->private_data;
 200
 201         do {
 202                 wait_event(fc->reserved_req_waitq, ff->reserved_req);
 203                 spin_lock(&fc->lock);
 204                 if (ff->reserved_req) {
 205                         req = ff->reserved_req;
 206                         ff->reserved_req = NULL;
 207                         req->stolen_file = get_file(file);
 208                 }
 209                 spin_unlock(&fc->lock);
 210         } while (!req);
 211
 212         return req;
 213 }
 214
 215 /*
 216  * Put stolen request back into fuse_file->reserved_req
 217  */
 218 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
 219 {
 220         struct file *file = req->stolen_file;
 221         struct fuse_file *ff = file->private_data;
 222
 223         spin_lock(&fc->lock);
 224         fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
 225         BUG_ON(ff->reserved_req);
 226         ff->reserved_req = req;
 227         wake_up_all(&fc->reserved_req_waitq);
 228         spin_unlock(&fc->lock);
 229         fput(file);
 230 }
 231
 232 /*
 233  * Gets a requests for a file operation, always succeeds
 234  *
 235  * This is used for sending the FLUSH request, which must get to
 236  * userspace, due to POSIX locks which may need to be unlocked.
 237  *
 238  * If allocation fails due to OOM, use the reserved request in
 239  * fuse_file.
 240  *
 241  * This is very unlikely to deadlock accidentally, since the
 242  * filesystem should not have it's own file open.  If deadlock is
 243  * intentional, it can still be broken by "aborting" the filesystem.
 244  */
 245 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 246                                              struct file *file)
 247 {
 248         struct fuse_req *req;
 249
 250         atomic_inc(&fc->num_waiting);
 251         wait_event(fc->blocked_waitq, fc->initialized);
 252         /* Matches smp_wmb() in fuse_set_initialized() */
 253         smp_rmb();
 254         req = fuse_request_alloc(0);
 255         if (!req)
 256                 req = get_reserved_req(fc, file);
 257
 258         fuse_req_init_context(req);
 259         __set_bit(FR_WAITING, &req->flags);
 260         __clear_bit(FR_BACKGROUND, &req->flags);
 261         return req;
 262 }
 263
 264 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 265 {
 266         if (atomic_dec_and_test(&req->count)) {
 267                 if (test_bit(FR_BACKGROUND, &req->flags)) {
 268                         /*
 269                          * We get here in the unlikely case that a background
 270                          * request was allocated but not sent
 271                          */
 272                         spin_lock(&fc->lock);
 273                         if (!fc->blocked)
 274                                 wake_up(&fc->blocked_waitq);
 275                         spin_unlock(&fc->lock);
 276                 }
 277
 278                 if (test_bit(FR_WAITING, &req->flags)) {
 279                         __clear_bit(FR_WAITING, &req->flags);
 280                         atomic_dec(&fc->num_waiting);
 281                 }
 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_iqueue *fiq)
 303 {
 304         return ++fiq->reqctr;
 305 }
 306
 307 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
 308 {
 309         req->in.h.len = sizeof(struct fuse_in_header) +
 310                 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
 311         list_add_tail(&req->list, &fiq->pending);
 312         wake_up_locked(&fiq->waitq);
 313         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 314 }
 315
 316 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 317                        u64 nodeid, u64 nlookup)
 318 {
 319         struct fuse_iqueue *fiq = &fc->iq;
 320
 321         forget->forget_one.nodeid = nodeid;
 322         forget->forget_one.nlookup = nlookup;
 323
 324         spin_lock(&fiq->waitq.lock);
 325         if (fiq->connected) {
 326                 fiq->forget_list_tail->next = forget;
 327                 fiq->forget_list_tail = forget;
 328                 wake_up_locked(&fiq->waitq);
 329                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 330         } else {
 331                 kfree(forget);
 332         }
 333         spin_unlock(&fiq->waitq.lock);
 334 }
 335
 336 static void flush_bg_queue(struct fuse_conn *fc)
 337 {
 338         while (fc->active_background < fc->max_background &&
 339                !list_empty(&fc->bg_queue)) {
 340                 struct fuse_req *req;
 341                 struct fuse_iqueue *fiq = &fc->iq;
 342
 343                 req = list_entry(fc->bg_queue.next, struct fuse_req, list);
 344                 list_del(&req->list);
 345                 fc->active_background++;
 346                 spin_lock(&fiq->waitq.lock);
 347                 req->in.h.unique = fuse_get_unique(fiq);
 348                 queue_request(fiq, req);
 349                 spin_unlock(&fiq->waitq.lock);
 350         }
 351 }
 352
 353 /*
 354  * This function is called when a request is finished.  Either a reply
 355  * has arrived or it was aborted (and not yet sent) or some error
 356  * occurred during communication with userspace, or the device file
 357  * was closed.  The requester thread is woken up (if still waiting),
 358  * the 'end' callback is called if given, else the reference to the
 359  * request is released
 360  */
 361 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 362 {
 363         struct fuse_iqueue *fiq = &fc->iq;
 364
 365         if (test_and_set_bit(FR_FINISHED, &req->flags))
 366                 return;
 367
 368         spin_lock(&fiq->waitq.lock);
 369         list_del_init(&req->intr_entry);
 370         spin_unlock(&fiq->waitq.lock);
 371         WARN_ON(test_bit(FR_PENDING, &req->flags));
 372         WARN_ON(test_bit(FR_SENT, &req->flags));
 373         if (test_bit(FR_BACKGROUND, &req->flags)) {
 374                 spin_lock(&fc->lock);
 375                 clear_bit(FR_BACKGROUND, &req->flags);
 376                 if (fc->num_background == fc->max_background)
 377                         fc->blocked = 0;
 378
 379                 /* Wake up next waiter, if any */
 380                 if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
 381                         wake_up(&fc->blocked_waitq);
 382
 383                 if (fc->num_background == fc->congestion_threshold &&
 384                     fc->connected && fc->bdi_initialized) {
 385                         clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
 386                         clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
 387                 }
 388                 fc->num_background--;
 389                 fc->active_background--;
 390                 flush_bg_queue(fc);
 391                 spin_unlock(&fc->lock);
 392         }
 393         wake_up(&req->waitq);
 394         if (req->end)
 395                 req->end(fc, req);
 396         fuse_put_request(fc, req);
 397 }
 398
 399 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
 400 {
 401         spin_lock(&fiq->waitq.lock);
 402         if (list_empty(&req->intr_entry)) {
 403                 list_add_tail(&req->intr_entry, &fiq->interrupts);
 404                 wake_up_locked(&fiq->waitq);
 405         }
 406         spin_unlock(&fiq->waitq.lock);
 407         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 408 }
 409
 410 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 411 {
 412         struct fuse_iqueue *fiq = &fc->iq;
 413         int err;
 414
 415         if (!fc->no_interrupt) {
 416                 /* Any signal may interrupt this */
 417                 err = wait_event_interruptible(req->waitq,
 418                                         test_bit(FR_FINISHED, &req->flags));
 419                 if (!err)
 420                         return;
 421
 422                 set_bit(FR_INTERRUPTED, &req->flags);
 423                 /* matches barrier in fuse_dev_do_read() */
 424                 smp_mb__after_atomic();
 425                 if (test_bit(FR_SENT, &req->flags))
 426                         queue_interrupt(fiq, req);
 427         }
 428
 429         if (!test_bit(FR_FORCE, &req->flags)) {
 430                 /* Only fatal signals may interrupt this */
 431                 err = wait_event_killable(req->waitq,
 432                                         test_bit(FR_FINISHED, &req->flags));
 433                 if (!err)
 434                         return;
 435
 436                 spin_lock(&fiq->waitq.lock);
 437                 /* Request is not yet in userspace, bail out */
 438                 if (test_bit(FR_PENDING, &req->flags)) {
 439                         list_del(&req->list);
 440                         spin_unlock(&fiq->waitq.lock);
 441                         __fuse_put_request(req);
 442                         req->out.h.error = -EINTR;
 443                         return;
 444                 }
 445                 spin_unlock(&fiq->waitq.lock);
 446         }
 447
 448         /*
 449          * Either request is already in userspace, or it was forced.
 450          * Wait it out.
 451          */
 452         wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
 453 }
 454
 455 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 456 {
 457         struct fuse_iqueue *fiq = &fc->iq;
 458
 459         BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
 460         spin_lock(&fiq->waitq.lock);
 461         if (!fiq->connected) {
 462                 spin_unlock(&fiq->waitq.lock);
 463                 req->out.h.error = -ENOTCONN;
 464         } else {
 465                 req->in.h.unique = fuse_get_unique(fiq);
 466                 queue_request(fiq, req);
 467                 /* acquire extra reference, since request is still needed
 468                    after request_end() */
 469                 __fuse_get_request(req);
 470                 spin_unlock(&fiq->waitq.lock);
 471
 472                 request_wait_answer(fc, req);
 473                 /* Pairs with smp_wmb() in request_end() */
 474                 smp_rmb();
 475         }
 476 }
 477
 478 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 479 {
 480         __set_bit(FR_ISREPLY, &req->flags);
 481         if (!test_bit(FR_WAITING, &req->flags)) {
 482                 __set_bit(FR_WAITING, &req->flags);
 483                 atomic_inc(&fc->num_waiting);
 484         }
 485         __fuse_request_send(fc, req);
 486 }
 487 EXPORT_SYMBOL_GPL(fuse_request_send);
 488
 489 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
 490 {
 491         if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
 492                 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
 493
 494         if (fc->minor < 9) {
 495                 switch (args->in.h.opcode) {
 496                 case FUSE_LOOKUP:
 497                 case FUSE_CREATE:
 498                 case FUSE_MKNOD:
 499                 case FUSE_MKDIR:
 500                 case FUSE_SYMLINK:
 501                 case FUSE_LINK:
 502                         args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 503                         break;
 504                 case FUSE_GETATTR:
 505                 case FUSE_SETATTR:
 506                         args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 507                         break;
 508                 }
 509         }
 510         if (fc->minor < 12) {
 511                 switch (args->in.h.opcode) {
 512                 case FUSE_CREATE:
 513                         args->in.args[0].size = sizeof(struct fuse_open_in);
 514                         break;
 515                 case FUSE_MKNOD:
 516                         args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
 517                         break;
 518                 }
 519         }
 520 }
 521
 522 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 523 {
 524         struct fuse_req *req;
 525         ssize_t ret;
 526
 527         req = fuse_get_req(fc, 0);
 528         if (IS_ERR(req))
 529                 return PTR_ERR(req);
 530
 531         /* Needs to be done after fuse_get_req() so that fc->minor is valid */
 532         fuse_adjust_compat(fc, args);
 533
 534         req->in.h.opcode = args->in.h.opcode;
 535         req->in.h.nodeid = args->in.h.nodeid;
 536         req->in.numargs = args->in.numargs;
 537         memcpy(req->in.args, args->in.args,
 538                args->in.numargs * sizeof(struct fuse_in_arg));
 539         req->out.argvar = args->out.argvar;
 540         req->out.numargs = args->out.numargs;
 541         memcpy(req->out.args, args->out.args,
 542                args->out.numargs * sizeof(struct fuse_arg));
 543         fuse_request_send(fc, req);
 544         ret = req->out.h.error;
 545         if (!ret && args->out.argvar) {
 546                 BUG_ON(args->out.numargs != 1);
 547                 ret = req->out.args[0].size;
 548         }
 549         fuse_put_request(fc, req);
 550
 551         return ret;
 552 }
 553
 554 /*
 555  * Called under fc->lock
 556  *
 557  * fc->connected must have been checked previously
 558  */
 559 void fuse_request_send_background_locked(struct fuse_conn *fc,
 560                                          struct fuse_req *req)
 561 {
 562         BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
 563         if (!test_bit(FR_WAITING, &req->flags)) {
 564                 __set_bit(FR_WAITING, &req->flags);
 565                 atomic_inc(&fc->num_waiting);
 566         }
 567         __set_bit(FR_ISREPLY, &req->flags);
 568         fc->num_background++;
 569         if (fc->num_background == fc->max_background)
 570                 fc->blocked = 1;
 571         if (fc->num_background == fc->congestion_threshold &&
 572             fc->bdi_initialized) {
 573                 set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
 574                 set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
 575         }
 576         list_add_tail(&req->list, &fc->bg_queue);
 577         flush_bg_queue(fc);
 578 }
 579
 580 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
 581 {
 582         BUG_ON(!req->end);
 583         spin_lock(&fc->lock);
 584         if (fc->connected) {
 585                 fuse_request_send_background_locked(fc, req);
 586                 spin_unlock(&fc->lock);
 587         } else {
 588                 spin_unlock(&fc->lock);
 589                 req->out.h.error = -ENOTCONN;
 590                 req->end(fc, req);
 591                 fuse_put_request(fc, req);
 592         }
 593 }
 594 EXPORT_SYMBOL_GPL(fuse_request_send_background);
 595
 596 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
 597                                           struct fuse_req *req, u64 unique)
 598 {
 599         int err = -ENODEV;
 600         struct fuse_iqueue *fiq = &fc->iq;
 601
 602         __clear_bit(FR_ISREPLY, &req->flags);
 603         req->in.h.unique = unique;
 604         spin_lock(&fiq->waitq.lock);
 605         if (fiq->connected) {
 606                 queue_request(fiq, req);
 607                 err = 0;
 608         }
 609         spin_unlock(&fiq->waitq.lock);
 610
 611         return err;
 612 }
 613
 614 void fuse_force_forget(struct file *file, u64 nodeid)
 615 {
 616         struct inode *inode = file_inode(file);
 617         struct fuse_conn *fc = get_fuse_conn(inode);
 618         struct fuse_req *req;
 619         struct fuse_forget_in inarg;
 620
 621         memset(&inarg, 0, sizeof(inarg));
 622         inarg.nlookup = 1;
 623         req = fuse_get_req_nofail_nopages(fc, file);
 624         req->in.h.opcode = FUSE_FORGET;
 625         req->in.h.nodeid = nodeid;
 626         req->in.numargs = 1;
 627         req->in.args[0].size = sizeof(inarg);
 628         req->in.args[0].value = &inarg;
 629         __clear_bit(FR_ISREPLY, &req->flags);
 630         __fuse_request_send(fc, req);
 631         /* ignore errors */
 632         fuse_put_request(fc, req);
 633 }
 634
 635 /*
 636  * Lock the request.  Up to the next unlock_request() there mustn't be
 637  * anything that could cause a page-fault.  If the request was already
 638  * aborted bail out.
 639  */
 640 static int lock_request(struct fuse_req *req)
 641 {
 642         int err = 0;
 643         if (req) {
 644                 spin_lock(&req->waitq.lock);
 645                 if (test_bit(FR_ABORTED, &req->flags))
 646                         err = -ENOENT;
 647                 else
 648                         set_bit(FR_LOCKED, &req->flags);
 649                 spin_unlock(&req->waitq.lock);
 650         }
 651         return err;
 652 }
 653
 654 /*
 655  * Unlock request.  If it was aborted while locked, caller is responsible
 656  * for unlocking and ending the request.
 657  */
 658 static int unlock_request(struct fuse_req *req)
 659 {
 660         int err = 0;
 661         if (req) {
 662                 spin_lock(&req->waitq.lock);
 663                 if (test_bit(FR_ABORTED, &req->flags))
 664                         err = -ENOENT;
 665                 else
 666                         clear_bit(FR_LOCKED, &req->flags);
 667                 spin_unlock(&req->waitq.lock);
 668         }
 669         return err;
 670 }
 671
 672 struct fuse_copy_state {
 673         int write;
 674         struct fuse_req *req;
 675         struct iov_iter *iter;
 676         struct pipe_buffer *pipebufs;
 677         struct pipe_buffer *currbuf;
 678         struct pipe_inode_info *pipe;
 679         unsigned long nr_segs;
 680         struct page *pg;
 681         unsigned len;
 682         unsigned offset;
 683         unsigned move_pages:1;
 684 };
 685
 686 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
 687                            struct iov_iter *iter)
 688 {
 689         memset(cs, 0, sizeof(*cs));
 690         cs->write = write;
 691         cs->iter = iter;
 692 }
 693
 694 /* Unmap and put previous page of userspace buffer */
 695 static void fuse_copy_finish(struct fuse_copy_state *cs)
 696 {
 697         if (cs->currbuf) {
 698                 struct pipe_buffer *buf = cs->currbuf;
 699
 700                 if (cs->write)
 701                         buf->len = PAGE_SIZE - cs->len;
 702                 cs->currbuf = NULL;
 703         } else if (cs->pg) {
 704                 if (cs->write) {
 705                         flush_dcache_page(cs->pg);
 706                         set_page_dirty_lock(cs->pg);
 707                 }
 708                 put_page(cs->pg);
 709         }
 710         cs->pg = NULL;
 711 }
 712
 713 /*
 714  * Get another pagefull of userspace buffer, and map it to kernel
 715  * address space, and lock request
 716  */
 717 static int fuse_copy_fill(struct fuse_copy_state *cs)
 718 {
 719         struct page *page;
 720         int err;
 721
 722         err = unlock_request(cs->req);
 723         if (err)
 724                 return err;
 725
 726         fuse_copy_finish(cs);
 727         if (cs->pipebufs) {
 728                 struct pipe_buffer *buf = cs->pipebufs;
 729
 730                 if (!cs->write) {
 731                         err = pipe_buf_confirm(cs->pipe, buf);
 732                         if (err)
 733                                 return err;
 734
 735                         BUG_ON(!cs->nr_segs);
 736                         cs->currbuf = buf;
 737                         cs->pg = buf->page;
 738                         cs->offset = buf->offset;
 739                         cs->len = buf->len;
 740                         cs->pipebufs++;
 741                         cs->nr_segs--;
 742                 } else {
 743                         if (cs->nr_segs == cs->pipe->buffers)
 744                                 return -EIO;
 745
 746                         page = alloc_page(GFP_HIGHUSER);
 747                         if (!page)
 748                                 return -ENOMEM;
 749
 750                         buf->page = page;
 751                         buf->offset = 0;
 752                         buf->len = 0;
 753
 754                         cs->currbuf = buf;
 755                         cs->pg = page;
 756                         cs->offset = 0;
 757                         cs->len = PAGE_SIZE;
 758                         cs->pipebufs++;
 759                         cs->nr_segs++;
 760                 }
 761         } else {
 762                 size_t off;
 763                 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
 764                 if (err < 0)
 765                         return err;
 766                 BUG_ON(!err);
 767                 cs->len = err;
 768                 cs->offset = off;
 769                 cs->pg = page;
 770                 iov_iter_advance(cs->iter, err);
 771         }
 772
 773         return lock_request(cs->req);
 774 }
 775
 776 /* Do as much copy to/from userspace buffer as we can */
 777 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 778 {
 779         unsigned ncpy = min(*size, cs->len);
 780         if (val) {
 781                 void *pgaddr = kmap_atomic(cs->pg);
 782                 void *buf = pgaddr + cs->offset;
 783
 784                 if (cs->write)
 785                         memcpy(buf, *val, ncpy);
 786                 else
 787                         memcpy(*val, buf, ncpy);
 788
 789                 kunmap_atomic(pgaddr);
 790                 *val += ncpy;
 791         }
 792         *size -= ncpy;
 793         cs->len -= ncpy;
 794         cs->offset += ncpy;
 795         return ncpy;
 796 }
 797
 798 static int fuse_check_page(struct page *page)
 799 {
 800         if (page_mapcount(page) ||
 801             page->mapping != NULL ||
 802             page_count(page) != 1 ||
 803             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 804              ~(1 << PG_locked |
 805                1 << PG_referenced |
 806                1 << PG_uptodate |
 807                1 << PG_lru |
 808                1 << PG_active |
 809                1 << PG_reclaim))) {
 810                 printk(KERN_WARNING "fuse: trying to steal weird page\n");
 811                 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);
 812                 return 1;
 813         }
 814         return 0;
 815 }
 816
 817 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 818 {
 819         int err;
 820         struct page *oldpage = *pagep;
 821         struct page *newpage;
 822         struct pipe_buffer *buf = cs->pipebufs;
 823
 824         err = unlock_request(cs->req);
 825         if (err)
 826                 return err;
 827
 828         fuse_copy_finish(cs);
 829
 830         err = pipe_buf_confirm(cs->pipe, buf);
 831         if (err)
 832                 return err;
 833
 834         BUG_ON(!cs->nr_segs);
 835         cs->currbuf = buf;
 836         cs->len = buf->len;
 837         cs->pipebufs++;
 838         cs->nr_segs--;
 839
 840         if (cs->len != PAGE_SIZE)
 841                 goto out_fallback;
 842
 843         if (pipe_buf_steal(cs->pipe, buf) != 0)
 844                 goto out_fallback;
 845
 846         newpage = buf->page;
 847
 848         if (!PageUptodate(newpage))
 849                 SetPageUptodate(newpage);
 850
 851         ClearPageMappedToDisk(newpage);
 852
 853         if (fuse_check_page(newpage) != 0)
 854                 goto out_fallback_unlock;
 855
 856         /*
 857          * This is a new and locked page, it shouldn't be mapped or
 858          * have any special flags on it
 859          */
 860         if (WARN_ON(page_mapped(oldpage)))
 861                 goto out_fallback_unlock;
 862         if (WARN_ON(page_has_private(oldpage)))
 863                 goto out_fallback_unlock;
 864         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 865                 goto out_fallback_unlock;
 866         if (WARN_ON(PageMlocked(oldpage)))
 867                 goto out_fallback_unlock;
 868
 869         err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 870         if (err) {
 871                 unlock_page(newpage);
 872                 return err;
 873         }
 874
 875         get_page(newpage);
 876
 877         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 878                 lru_cache_add_file(newpage);
 879
 880         err = 0;
 881         spin_lock(&cs->req->waitq.lock);
 882         if (test_bit(FR_ABORTED, &cs->req->flags))
 883                 err = -ENOENT;
 884         else
 885                 *pagep = newpage;
 886         spin_unlock(&cs->req->waitq.lock);
 887
 888         if (err) {
 889                 unlock_page(newpage);
 890                 put_page(newpage);
 891                 return err;
 892         }
 893
 894         unlock_page(oldpage);
 895         put_page(oldpage);
 896         cs->len = 0;
 897
 898         return 0;
 899
 900 out_fallback_unlock:
 901         unlock_page(newpage);
 902 out_fallback:
 903         cs->pg = buf->page;
 904         cs->offset = buf->offset;
 905
 906         err = lock_request(cs->req);
 907         if (err)
 908                 return err;
 909
 910         return 1;
 911 }
 912
 913 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 914                          unsigned offset, unsigned count)
 915 {
 916         struct pipe_buffer *buf;
 917         int err;
 918
 919         if (cs->nr_segs == cs->pipe->buffers)
 920                 return -EIO;
 921
 922         err = unlock_request(cs->req);
 923         if (err)
 924                 return err;
 925
 926         fuse_copy_finish(cs);
 927
 928         buf = cs->pipebufs;
 929         get_page(page);
 930         buf->page = page;
 931         buf->offset = offset;
 932         buf->len = count;
 933
 934         cs->pipebufs++;
 935         cs->nr_segs++;
 936         cs->len = 0;
 937
 938         return 0;
 939 }
 940
 941 /*
 942  * Copy a page in the request to/from the userspace buffer.  Must be
 943  * done atomically
 944  */
 945 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 946                           unsigned offset, unsigned count, int zeroing)
 947 {
 948         int err;
 949         struct page *page = *pagep;
 950
 951         if (page && zeroing && count < PAGE_SIZE)
 952                 clear_highpage(page);
 953
 954         while (count) {
 955                 if (cs->write && cs->pipebufs && page) {
 956                         return fuse_ref_page(cs, page, offset, count);
 957                 } else if (!cs->len) {
 958                         if (cs->move_pages && page &&
 959                             offset == 0 && count == PAGE_SIZE) {
 960                                 err = fuse_try_move_page(cs, pagep);
 961                                 if (err <= 0)
 962                                         return err;
 963                         } else {
 964                                 err = fuse_copy_fill(cs);
 965                                 if (err)
 966                                         return err;
 967                         }
 968                 }
 969                 if (page) {
 970                         void *mapaddr = kmap_atomic(page);
 971                         void *buf = mapaddr + offset;
 972                         offset += fuse_copy_do(cs, &buf, &count);
 973                         kunmap_atomic(mapaddr);
 974                 } else
 975                         offset += fuse_copy_do(cs, NULL, &count);
 976         }
 977         if (page && !cs->write)
 978                 flush_dcache_page(page);
 979         return 0;
 980 }
 981
 982 /* Copy pages in the request to/from userspace buffer */
 983 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 984                            int zeroing)
 985 {
 986         unsigned i;
 987         struct fuse_req *req = cs->req;
 988
 989         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
 990                 int err;
 991                 unsigned offset = req->page_descs[i].offset;
 992                 unsigned count = min(nbytes, req->page_descs[i].length);
 993
 994                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
 995                                      zeroing);
 996                 if (err)
 997                         return err;
 998
 999                 nbytes -= count;
1000         }
1001         return 0;
1002 }
1003
1004 /* Copy a single argument in the request to/from userspace buffer */
1005 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1006 {
1007         while (size) {
1008                 if (!cs->len) {
1009                         int err = fuse_copy_fill(cs);
1010                         if (err)
1011                                 return err;
1012                 }
1013                 fuse_copy_do(cs, &val, &size);
1014         }
1015         return 0;
1016 }
1017
1018 /* Copy request arguments to/from userspace buffer */
1019 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1020                           unsigned argpages, struct fuse_arg *args,
1021                           int zeroing)
1022 {
1023         int err = 0;
1024         unsigned i;
1025
1026         for (i = 0; !err && i < numargs; i++)  {
1027                 struct fuse_arg *arg = &args[i];
1028                 if (i == numargs - 1 && argpages)
1029                         err = fuse_copy_pages(cs, arg->size, zeroing);
1030                 else
1031                         err = fuse_copy_one(cs, arg->value, arg->size);
1032         }
1033         return err;
1034 }
1035
1036 static int forget_pending(struct fuse_iqueue *fiq)
1037 {
1038         return fiq->forget_list_head.next != NULL;
1039 }
1040
1041 static int request_pending(struct fuse_iqueue *fiq)
1042 {
1043         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1044                 forget_pending(fiq);
1045 }
1046
1047 /*
1048  * Transfer an interrupt request to userspace
1049  *
1050  * Unlike other requests this is assembled on demand, without a need
1051  * to allocate a separate fuse_req structure.
1052  *
1053  * Called with fiq->waitq.lock held, releases it
1054  */
1055 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1056                                struct fuse_copy_state *cs,
1057                                size_t nbytes, struct fuse_req *req)
1058 __releases(fiq->waitq.lock)
1059 {
1060         struct fuse_in_header ih;
1061         struct fuse_interrupt_in arg;
1062         unsigned reqsize = sizeof(ih) + sizeof(arg);
1063         int err;
1064
1065         list_del_init(&req->intr_entry);
1066         req->intr_unique = fuse_get_unique(fiq);
1067         memset(&ih, 0, sizeof(ih));
1068         memset(&arg, 0, sizeof(arg));
1069         ih.len = reqsize;
1070         ih.opcode = FUSE_INTERRUPT;
1071         ih.unique = req->intr_unique;
1072         arg.unique = req->in.h.unique;
1073
1074         spin_unlock(&fiq->waitq.lock);
1075         if (nbytes < reqsize)
1076                 return -EINVAL;
1077
1078         err = fuse_copy_one(cs, &ih, sizeof(ih));
1079         if (!err)
1080                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1081         fuse_copy_finish(cs);
1082
1083         return err ? err : reqsize;
1084 }
1085
1086 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1087                                                unsigned max,
1088                                                unsigned *countp)
1089 {
1090         struct fuse_forget_link *head = fiq->forget_list_head.next;
1091         struct fuse_forget_link **newhead = &head;
1092         unsigned count;
1093
1094         for (count = 0; *newhead != NULL && count < max; count++)
1095                 newhead = &(*newhead)->next;
1096
1097         fiq->forget_list_head.next = *newhead;
1098         *newhead = NULL;
1099         if (fiq->forget_list_head.next == NULL)
1100                 fiq->forget_list_tail = &fiq->forget_list_head;
1101
1102         if (countp != NULL)
1103                 *countp = count;
1104
1105         return head;
1106 }
1107
1108 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1109                                    struct fuse_copy_state *cs,
1110                                    size_t nbytes)
1111 __releases(fiq->waitq.lock)
1112 {
1113         int err;
1114         struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1115         struct fuse_forget_in arg = {
1116                 .nlookup = forget->forget_one.nlookup,
1117         };
1118         struct fuse_in_header ih = {
1119                 .opcode = FUSE_FORGET,
1120                 .nodeid = forget->forget_one.nodeid,
1121                 .unique = fuse_get_unique(fiq),
1122                 .len = sizeof(ih) + sizeof(arg),
1123         };
1124
1125         spin_unlock(&fiq->waitq.lock);
1126         kfree(forget);
1127         if (nbytes < ih.len)
1128                 return -EINVAL;
1129
1130         err = fuse_copy_one(cs, &ih, sizeof(ih));
1131         if (!err)
1132                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1133         fuse_copy_finish(cs);
1134
1135         if (err)
1136                 return err;
1137
1138         return ih.len;
1139 }
1140
1141 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1142                                    struct fuse_copy_state *cs, size_t nbytes)
1143 __releases(fiq->waitq.lock)
1144 {
1145         int err;
1146         unsigned max_forgets;
1147         unsigned count;
1148         struct fuse_forget_link *head;
1149         struct fuse_batch_forget_in arg = { .count = 0 };
1150         struct fuse_in_header ih = {
1151                 .opcode = FUSE_BATCH_FORGET,
1152                 .unique = fuse_get_unique(fiq),
1153                 .len = sizeof(ih) + sizeof(arg),
1154         };
1155
1156         if (nbytes < ih.len) {
1157                 spin_unlock(&fiq->waitq.lock);
1158                 return -EINVAL;
1159         }
1160
1161         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1162         head = dequeue_forget(fiq, max_forgets, &count);
1163         spin_unlock(&fiq->waitq.lock);
1164
1165         arg.count = count;
1166         ih.len += count * sizeof(struct fuse_forget_one);
1167         err = fuse_copy_one(cs, &ih, sizeof(ih));
1168         if (!err)
1169                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1170
1171         while (head) {
1172                 struct fuse_forget_link *forget = head;
1173
1174                 if (!err) {
1175                         err = fuse_copy_one(cs, &forget->forget_one,
1176                                             sizeof(forget->forget_one));
1177                 }
1178                 head = forget->next;
1179                 kfree(forget);
1180         }
1181
1182         fuse_copy_finish(cs);
1183
1184         if (err)
1185                 return err;
1186
1187         return ih.len;
1188 }
1189
1190 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1191                             struct fuse_copy_state *cs,
1192                             size_t nbytes)
1193 __releases(fiq->waitq.lock)
1194 {
1195         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1196                 return fuse_read_single_forget(fiq, cs, nbytes);
1197         else
1198                 return fuse_read_batch_forget(fiq, cs, nbytes);
1199 }
1200
1201 /*
1202  * Read a single request into the userspace filesystem's buffer.  This
1203  * function waits until a request is available, then removes it from
1204  * the pending list and copies request data to userspace buffer.  If
1205  * no reply is needed (FORGET) or request has been aborted or there
1206  * was an error during the copying then it's finished by calling
1207  * request_end().  Otherwise add it to the processing list, and set
1208  * the 'sent' flag.
1209  */
1210 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1211                                 struct fuse_copy_state *cs, size_t nbytes)
1212 {
1213         ssize_t err;
1214         struct fuse_conn *fc = fud->fc;
1215         struct fuse_iqueue *fiq = &fc->iq;
1216         struct fuse_pqueue *fpq = &fud->pq;
1217         struct fuse_req *req;
1218         struct fuse_in *in;
1219         unsigned reqsize;
1220
1221  restart:
1222         spin_lock(&fiq->waitq.lock);
1223         err = -EAGAIN;
1224         if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1225             !request_pending(fiq))
1226                 goto err_unlock;
1227
1228         err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1229                                 !fiq->connected || request_pending(fiq));
1230         if (err)
1231                 goto err_unlock;
1232
1233         err = -ENODEV;
1234         if (!fiq->connected)
1235                 goto err_unlock;
1236
1237         if (!list_empty(&fiq->interrupts)) {
1238                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1239                                  intr_entry);
1240                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1241         }
1242
1243         if (forget_pending(fiq)) {
1244                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1245                         return fuse_read_forget(fc, fiq, cs, nbytes);
1246
1247                 if (fiq->forget_batch <= -8)
1248                         fiq->forget_batch = 16;
1249         }
1250
1251         req = list_entry(fiq->pending.next, struct fuse_req, list);
1252         clear_bit(FR_PENDING, &req->flags);
1253         list_del_init(&req->list);
1254         spin_unlock(&fiq->waitq.lock);
1255
1256         in = &req->in;
1257         reqsize = in->h.len;
1258         /* If request is too large, reply with an error and restart the read */
1259         if (nbytes < reqsize) {
1260                 req->out.h.error = -EIO;
1261                 /* SETXATTR is special, since it may contain too large data */
1262                 if (in->h.opcode == FUSE_SETXATTR)
1263                         req->out.h.error = -E2BIG;
1264                 request_end(fc, req);
1265                 goto restart;
1266         }
1267         spin_lock(&fpq->lock);
1268         list_add(&req->list, &fpq->io);
1269         spin_unlock(&fpq->lock);
1270         cs->req = req;
1271         err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1272         if (!err)
1273                 err = fuse_copy_args(cs, in->numargs, in->argpages,
1274                                      (struct fuse_arg *) in->args, 0);
1275         fuse_copy_finish(cs);
1276         spin_lock(&fpq->lock);
1277         clear_bit(FR_LOCKED, &req->flags);
1278         if (!fpq->connected) {
1279                 err = -ENODEV;
1280                 goto out_end;
1281         }
1282         if (err) {
1283                 req->out.h.error = -EIO;
1284                 goto out_end;
1285         }
1286         if (!test_bit(FR_ISREPLY, &req->flags)) {
1287                 err = reqsize;
1288                 goto out_end;
1289         }
1290         list_move_tail(&req->list, &fpq->processing);
1291         spin_unlock(&fpq->lock);
1292         set_bit(FR_SENT, &req->flags);
1293         /* matches barrier in request_wait_answer() */
1294         smp_mb__after_atomic();
1295         if (test_bit(FR_INTERRUPTED, &req->flags))
1296                 queue_interrupt(fiq, req);
1297
1298         return reqsize;
1299
1300 out_end:
1301         if (!test_bit(FR_PRIVATE, &req->flags))
1302                 list_del_init(&req->list);
1303         spin_unlock(&fpq->lock);
1304         request_end(fc, req);
1305         return err;
1306
1307  err_unlock:
1308         spin_unlock(&fiq->waitq.lock);
1309         return err;
1310 }
1311
1312 static int fuse_dev_open(struct inode *inode, struct file *file)
1313 {
1314         /*
1315          * The fuse device's file's private_data is used to hold
1316          * the fuse_conn(ection) when it is mounted, and is used to
1317          * keep track of whether the file has been mounted already.
1318          */
1319         file->private_data = NULL;
1320         return 0;
1321 }
1322
1323 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1324 {
1325         struct fuse_copy_state cs;
1326         struct file *file = iocb->ki_filp;
1327         struct fuse_dev *fud = fuse_get_dev(file);
1328
1329         if (!fud)
1330                 return -EPERM;
1331
1332         if (!iter_is_iovec(to))
1333                 return -EINVAL;
1334
1335         fuse_copy_init(&cs, 1, to);
1336
1337         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1338 }
1339
1340 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1341                                     struct pipe_inode_info *pipe,
1342                                     size_t len, unsigned int flags)
1343 {
1344         int total, ret;
1345         int page_nr = 0;
1346         struct pipe_buffer *bufs;
1347         struct fuse_copy_state cs;
1348         struct fuse_dev *fud = fuse_get_dev(in);
1349
1350         if (!fud)
1351                 return -EPERM;
1352
1353         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1354         if (!bufs)
1355                 return -ENOMEM;
1356
1357         fuse_copy_init(&cs, 1, NULL);
1358         cs.pipebufs = bufs;
1359         cs.pipe = pipe;
1360         ret = fuse_dev_do_read(fud, in, &cs, len);
1361         if (ret < 0)
1362                 goto out;
1363
1364         if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1365                 ret = -EIO;
1366                 goto out;
1367         }
1368
1369         for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1370                 /*
1371                  * Need to be careful about this.  Having buf->ops in module
1372                  * code can Oops if the buffer persists after module unload.
1373                  */
1374                 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1375                 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1376                 if (unlikely(ret < 0))
1377                         break;
1378         }
1379         if (total)
1380                 ret = total;
1381 out:
1382         for (; page_nr < cs.nr_segs; page_nr++)
1383                 put_page(bufs[page_nr].page);
1384
1385         kfree(bufs);
1386         return ret;
1387 }
1388
1389 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1390                             struct fuse_copy_state *cs)
1391 {
1392         struct fuse_notify_poll_wakeup_out outarg;
1393         int err = -EINVAL;
1394
1395         if (size != sizeof(outarg))
1396                 goto err;
1397
1398         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1399         if (err)
1400                 goto err;
1401
1402         fuse_copy_finish(cs);
1403         return fuse_notify_poll_wakeup(fc, &outarg);
1404
1405 err:
1406         fuse_copy_finish(cs);
1407         return err;
1408 }
1409
1410 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1411                                    struct fuse_copy_state *cs)
1412 {
1413         struct fuse_notify_inval_inode_out outarg;
1414         int err = -EINVAL;
1415
1416         if (size != sizeof(outarg))
1417                 goto err;
1418
1419         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1420         if (err)
1421                 goto err;
1422         fuse_copy_finish(cs);
1423
1424         down_read(&fc->killsb);
1425         err = -ENOENT;
1426         if (fc->sb) {
1427                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1428                                                outarg.off, outarg.len);
1429         }
1430         up_read(&fc->killsb);
1431         return err;
1432
1433 err:
1434         fuse_copy_finish(cs);
1435         return err;
1436 }
1437
1438 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1439                                    struct fuse_copy_state *cs)
1440 {
1441         struct fuse_notify_inval_entry_out outarg;
1442         int err = -ENOMEM;
1443         char *buf;
1444         struct qstr name;
1445
1446         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1447         if (!buf)
1448                 goto err;
1449
1450         err = -EINVAL;
1451         if (size < sizeof(outarg))
1452                 goto err;
1453
1454         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1455         if (err)
1456                 goto err;
1457
1458         err = -ENAMETOOLONG;
1459         if (outarg.namelen > FUSE_NAME_MAX)
1460                 goto err;
1461
1462         err = -EINVAL;
1463         if (size != sizeof(outarg) + outarg.namelen + 1)
1464                 goto err;
1465
1466         name.name = buf;
1467         name.len = outarg.namelen;
1468         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1469         if (err)
1470                 goto err;
1471         fuse_copy_finish(cs);
1472         buf[outarg.namelen] = 0;
1473
1474         down_read(&fc->killsb);
1475         err = -ENOENT;
1476         if (fc->sb)
1477                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1478         up_read(&fc->killsb);
1479         kfree(buf);
1480         return err;
1481
1482 err:
1483         kfree(buf);
1484         fuse_copy_finish(cs);
1485         return err;
1486 }
1487
1488 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1489                               struct fuse_copy_state *cs)
1490 {
1491         struct fuse_notify_delete_out outarg;
1492         int err = -ENOMEM;
1493         char *buf;
1494         struct qstr name;
1495
1496         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1497         if (!buf)
1498                 goto err;
1499
1500         err = -EINVAL;
1501         if (size < sizeof(outarg))
1502                 goto err;
1503
1504         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1505         if (err)
1506                 goto err;
1507
1508         err = -ENAMETOOLONG;
1509         if (outarg.namelen > FUSE_NAME_MAX)
1510                 goto err;
1511
1512         err = -EINVAL;
1513         if (size != sizeof(outarg) + outarg.namelen + 1)
1514                 goto err;
1515
1516         name.name = buf;
1517         name.len = outarg.namelen;
1518         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1519         if (err)
1520                 goto err;
1521         fuse_copy_finish(cs);
1522         buf[outarg.namelen] = 0;
1523
1524         down_read(&fc->killsb);
1525         err = -ENOENT;
1526         if (fc->sb)
1527                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1528                                                outarg.child, &name);
1529         up_read(&fc->killsb);
1530         kfree(buf);
1531         return err;
1532
1533 err:
1534         kfree(buf);
1535         fuse_copy_finish(cs);
1536         return err;
1537 }
1538
1539 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1540                              struct fuse_copy_state *cs)
1541 {
1542         struct fuse_notify_store_out outarg;
1543         struct inode *inode;
1544         struct address_space *mapping;
1545         u64 nodeid;
1546         int err;
1547         pgoff_t index;
1548         unsigned int offset;
1549         unsigned int num;
1550         loff_t file_size;
1551         loff_t end;
1552
1553         err = -EINVAL;
1554         if (size < sizeof(outarg))
1555                 goto out_finish;
1556
1557         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1558         if (err)
1559                 goto out_finish;
1560
1561         err = -EINVAL;
1562         if (size - sizeof(outarg) != outarg.size)
1563                 goto out_finish;
1564
1565         nodeid = outarg.nodeid;
1566
1567         down_read(&fc->killsb);
1568
1569         err = -ENOENT;
1570         if (!fc->sb)
1571                 goto out_up_killsb;
1572
1573         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1574         if (!inode)
1575                 goto out_up_killsb;
1576
1577         mapping = inode->i_mapping;
1578         index = outarg.offset >> PAGE_SHIFT;
1579         offset = outarg.offset & ~PAGE_MASK;
1580         file_size = i_size_read(inode);
1581         end = outarg.offset + outarg.size;
1582         if (end > file_size) {
1583                 file_size = end;
1584                 fuse_write_update_size(inode, file_size);
1585         }
1586
1587         num = outarg.size;
1588         while (num) {
1589                 struct page *page;
1590                 unsigned int this_num;
1591
1592                 err = -ENOMEM;
1593                 page = find_or_create_page(mapping, index,
1594                                            mapping_gfp_mask(mapping));
1595                 if (!page)
1596                         goto out_iput;
1597
1598                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1599                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1600                 if (!err && offset == 0 &&
1601                     (this_num == PAGE_SIZE || file_size == end))
1602                         SetPageUptodate(page);
1603                 unlock_page(page);
1604                 put_page(page);
1605
1606                 if (err)
1607                         goto out_iput;
1608
1609                 num -= this_num;
1610                 offset = 0;
1611                 index++;
1612         }
1613
1614         err = 0;
1615
1616 out_iput:
1617         iput(inode);
1618 out_up_killsb:
1619         up_read(&fc->killsb);
1620 out_finish:
1621         fuse_copy_finish(cs);
1622         return err;
1623 }
1624
1625 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1626 {
1627         release_pages(req->pages, req->num_pages, false);
1628 }
1629
1630 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1631                          struct fuse_notify_retrieve_out *outarg)
1632 {
1633         int err;
1634         struct address_space *mapping = inode->i_mapping;
1635         struct fuse_req *req;
1636         pgoff_t index;
1637         loff_t file_size;
1638         unsigned int num;
1639         unsigned int offset;
1640         size_t total_len = 0;
1641         int num_pages;
1642
1643         offset = outarg->offset & ~PAGE_MASK;
1644         file_size = i_size_read(inode);
1645
1646         num = outarg->size;
1647         if (outarg->offset > file_size)
1648                 num = 0;
1649         else if (outarg->offset + num > file_size)
1650                 num = file_size - outarg->offset;
1651
1652         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1653         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1654
1655         req = fuse_get_req(fc, num_pages);
1656         if (IS_ERR(req))
1657                 return PTR_ERR(req);
1658
1659         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1660         req->in.h.nodeid = outarg->nodeid;
1661         req->in.numargs = 2;
1662         req->in.argpages = 1;
1663         req->page_descs[0].offset = offset;
1664         req->end = fuse_retrieve_end;
1665
1666         index = outarg->offset >> PAGE_SHIFT;
1667
1668         while (num && req->num_pages < num_pages) {
1669                 struct page *page;
1670                 unsigned int this_num;
1671
1672                 page = find_get_page(mapping, index);
1673                 if (!page)
1674                         break;
1675
1676                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1677                 req->pages[req->num_pages] = page;
1678                 req->page_descs[req->num_pages].length = this_num;
1679                 req->num_pages++;
1680
1681                 offset = 0;
1682                 num -= this_num;
1683                 total_len += this_num;
1684                 index++;
1685         }
1686         req->misc.retrieve_in.offset = outarg->offset;
1687         req->misc.retrieve_in.size = total_len;
1688         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1689         req->in.args[0].value = &req->misc.retrieve_in;
1690         req->in.args[1].size = total_len;
1691
1692         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1693         if (err)
1694                 fuse_retrieve_end(fc, req);
1695
1696         return err;
1697 }
1698
1699 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1700                                 struct fuse_copy_state *cs)
1701 {
1702         struct fuse_notify_retrieve_out outarg;
1703         struct inode *inode;
1704         int err;
1705
1706         err = -EINVAL;
1707         if (size != sizeof(outarg))
1708                 goto copy_finish;
1709
1710         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1711         if (err)
1712                 goto copy_finish;
1713
1714         fuse_copy_finish(cs);
1715
1716         down_read(&fc->killsb);
1717         err = -ENOENT;
1718         if (fc->sb) {
1719                 u64 nodeid = outarg.nodeid;
1720
1721                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1722                 if (inode) {
1723                         err = fuse_retrieve(fc, inode, &outarg);
1724                         iput(inode);
1725                 }
1726         }
1727         up_read(&fc->killsb);
1728
1729         return err;
1730
1731 copy_finish:
1732         fuse_copy_finish(cs);
1733         return err;
1734 }
1735
1736 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1737                        unsigned int size, struct fuse_copy_state *cs)
1738 {
1739         /* Don't try to move pages (yet) */
1740         cs->move_pages = 0;
1741
1742         switch (code) {
1743         case FUSE_NOTIFY_POLL:
1744                 return fuse_notify_poll(fc, size, cs);
1745
1746         case FUSE_NOTIFY_INVAL_INODE:
1747                 return fuse_notify_inval_inode(fc, size, cs);
1748
1749         case FUSE_NOTIFY_INVAL_ENTRY:
1750                 return fuse_notify_inval_entry(fc, size, cs);
1751
1752         case FUSE_NOTIFY_STORE:
1753                 return fuse_notify_store(fc, size, cs);
1754
1755         case FUSE_NOTIFY_RETRIEVE:
1756                 return fuse_notify_retrieve(fc, size, cs);
1757
1758         case FUSE_NOTIFY_DELETE:
1759                 return fuse_notify_delete(fc, size, cs);
1760
1761         default:
1762                 fuse_copy_finish(cs);
1763                 return -EINVAL;
1764         }
1765 }
1766
1767 /* Look up request on processing list by unique ID */
1768 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1769 {
1770         struct fuse_req *req;
1771
1772         list_for_each_entry(req, &fpq->processing, list) {
1773                 if (req->in.h.unique == unique || req->intr_unique == unique)
1774                         return req;
1775         }
1776         return NULL;
1777 }
1778
1779 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1780                          unsigned nbytes)
1781 {
1782         unsigned reqsize = sizeof(struct fuse_out_header);
1783
1784         if (out->h.error)
1785                 return nbytes != reqsize ? -EINVAL : 0;
1786
1787         reqsize += len_args(out->numargs, out->args);
1788
1789         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1790                 return -EINVAL;
1791         else if (reqsize > nbytes) {
1792                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1793                 unsigned diffsize = reqsize - nbytes;
1794                 if (diffsize > lastarg->size)
1795                         return -EINVAL;
1796                 lastarg->size -= diffsize;
1797         }
1798         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1799                               out->page_zeroing);
1800 }
1801
1802 /*
1803  * Write a single reply to a request.  First the header is copied from
1804  * the write buffer.  The request is then searched on the processing
1805  * list by the unique ID found in the header.  If found, then remove
1806  * it from the list and copy the rest of the buffer to the request.
1807  * The request is finished by calling request_end()
1808  */
1809 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1810                                  struct fuse_copy_state *cs, size_t nbytes)
1811 {
1812         int err;
1813         struct fuse_conn *fc = fud->fc;
1814         struct fuse_pqueue *fpq = &fud->pq;
1815         struct fuse_req *req;
1816         struct fuse_out_header oh;
1817
1818         if (nbytes < sizeof(struct fuse_out_header))
1819                 return -EINVAL;
1820
1821         err = fuse_copy_one(cs, &oh, sizeof(oh));
1822         if (err)
1823                 goto err_finish;
1824
1825         err = -EINVAL;
1826         if (oh.len != nbytes)
1827                 goto err_finish;
1828
1829         /*
1830          * Zero oh.unique indicates unsolicited notification message
1831          * and error contains notification code.
1832          */
1833         if (!oh.unique) {
1834                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1835                 return err ? err : nbytes;
1836         }
1837
1838         err = -EINVAL;
1839         if (oh.error <= -1000 || oh.error > 0)
1840                 goto err_finish;
1841
1842         spin_lock(&fpq->lock);
1843         err = -ENOENT;
1844         if (!fpq->connected)
1845                 goto err_unlock_pq;
1846
1847         req = request_find(fpq, oh.unique);
1848         if (!req)
1849                 goto err_unlock_pq;
1850
1851         /* Is it an interrupt reply? */
1852         if (req->intr_unique == oh.unique) {
1853                 spin_unlock(&fpq->lock);
1854
1855                 err = -EINVAL;
1856                 if (nbytes != sizeof(struct fuse_out_header))
1857                         goto err_finish;
1858
1859                 if (oh.error == -ENOSYS)
1860                         fc->no_interrupt = 1;
1861                 else if (oh.error == -EAGAIN)
1862                         queue_interrupt(&fc->iq, req);
1863
1864                 fuse_copy_finish(cs);
1865                 return nbytes;
1866         }
1867
1868         clear_bit(FR_SENT, &req->flags);
1869         list_move(&req->list, &fpq->io);
1870         req->out.h = oh;
1871         set_bit(FR_LOCKED, &req->flags);
1872         spin_unlock(&fpq->lock);
1873         cs->req = req;
1874         if (!req->out.page_replace)
1875                 cs->move_pages = 0;
1876
1877         err = copy_out_args(cs, &req->out, nbytes);
1878         fuse_copy_finish(cs);
1879
1880         spin_lock(&fpq->lock);
1881         clear_bit(FR_LOCKED, &req->flags);
1882         if (!fpq->connected)
1883                 err = -ENOENT;
1884         else if (err)
1885                 req->out.h.error = -EIO;
1886         if (!test_bit(FR_PRIVATE, &req->flags))
1887                 list_del_init(&req->list);
1888         spin_unlock(&fpq->lock);
1889
1890         request_end(fc, req);
1891
1892         return err ? err : nbytes;
1893
1894  err_unlock_pq:
1895         spin_unlock(&fpq->lock);
1896  err_finish:
1897         fuse_copy_finish(cs);
1898         return err;
1899 }
1900
1901 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1902 {
1903         struct fuse_copy_state cs;
1904         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1905
1906         if (!fud)
1907                 return -EPERM;
1908
1909         if (!iter_is_iovec(from))
1910                 return -EINVAL;
1911
1912         fuse_copy_init(&cs, 0, from);
1913
1914         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1915 }
1916
1917 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1918                                      struct file *out, loff_t *ppos,
1919                                      size_t len, unsigned int flags)
1920 {
1921         unsigned nbuf;
1922         unsigned idx;
1923         struct pipe_buffer *bufs;
1924         struct fuse_copy_state cs;
1925         struct fuse_dev *fud;
1926         size_t rem;
1927         ssize_t ret;
1928
1929         fud = fuse_get_dev(out);
1930         if (!fud)
1931                 return -EPERM;
1932
1933         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1934         if (!bufs)
1935                 return -ENOMEM;
1936
1937         pipe_lock(pipe);
1938         nbuf = 0;
1939         rem = 0;
1940         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1941                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1942
1943         ret = -EINVAL;
1944         if (rem < len) {
1945                 pipe_unlock(pipe);
1946                 goto out;
1947         }
1948
1949         rem = len;
1950         while (rem) {
1951                 struct pipe_buffer *ibuf;
1952                 struct pipe_buffer *obuf;
1953
1954                 BUG_ON(nbuf >= pipe->buffers);
1955                 BUG_ON(!pipe->nrbufs);
1956                 ibuf = &pipe->bufs[pipe->curbuf];
1957                 obuf = &bufs[nbuf];
1958
1959                 if (rem >= ibuf->len) {
1960                         *obuf = *ibuf;
1961                         ibuf->ops = NULL;
1962                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1963                         pipe->nrbufs--;
1964                 } else {
1965                         pipe_buf_get(pipe, ibuf);
1966                         *obuf = *ibuf;
1967                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1968                         obuf->len = rem;
1969                         ibuf->offset += obuf->len;
1970                         ibuf->len -= obuf->len;
1971                 }
1972                 nbuf++;
1973                 rem -= obuf->len;
1974         }
1975         pipe_unlock(pipe);
1976
1977         fuse_copy_init(&cs, 0, NULL);
1978         cs.pipebufs = bufs;
1979         cs.nr_segs = nbuf;
1980         cs.pipe = pipe;
1981
1982         if (flags & SPLICE_F_MOVE)
1983                 cs.move_pages = 1;
1984
1985         ret = fuse_dev_do_write(fud, &cs, len);
1986
1987         for (idx = 0; idx < nbuf; idx++)
1988                 pipe_buf_release(pipe, &bufs[idx]);
1989
1990 out:
1991         kfree(bufs);
1992         return ret;
1993 }
1994
1995 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1996 {
1997         unsigned mask = POLLOUT | POLLWRNORM;
1998         struct fuse_iqueue *fiq;
1999         struct fuse_dev *fud = fuse_get_dev(file);
2000
2001         if (!fud)
2002                 return POLLERR;
2003
2004         fiq = &fud->fc->iq;
2005         poll_wait(file, &fiq->waitq, wait);
2006
2007         spin_lock(&fiq->waitq.lock);
2008         if (!fiq->connected)
2009                 mask = POLLERR;
2010         else if (request_pending(fiq))
2011                 mask |= POLLIN | POLLRDNORM;
2012         spin_unlock(&fiq->waitq.lock);
2013
2014         return mask;
2015 }
2016
2017 /*
2018  * Abort all requests on the given list (pending or processing)
2019  *
2020  * This function releases and reacquires fc->lock
2021  */
2022 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2023 {
2024         while (!list_empty(head)) {
2025                 struct fuse_req *req;
2026                 req = list_entry(head->next, struct fuse_req, list);
2027                 req->out.h.error = -ECONNABORTED;
2028                 clear_bit(FR_PENDING, &req->flags);
2029                 clear_bit(FR_SENT, &req->flags);
2030                 list_del_init(&req->list);
2031                 request_end(fc, req);
2032         }
2033 }
2034
2035 static void end_polls(struct fuse_conn *fc)
2036 {
2037         struct rb_node *p;
2038
2039         p = rb_first(&fc->polled_files);
2040
2041         while (p) {
2042                 struct fuse_file *ff;
2043                 ff = rb_entry(p, struct fuse_file, polled_node);
2044                 wake_up_interruptible_all(&ff->poll_wait);
2045
2046                 p = rb_next(p);
2047         }
2048 }
2049
2050 /*
2051  * Abort all requests.
2052  *
2053  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2054  * filesystem.
2055  *
2056  * The same effect is usually achievable through killing the filesystem daemon
2057  * and all users of the filesystem.  The exception is the combination of an
2058  * asynchronous request and the tricky deadlock (see
2059  * Documentation/filesystems/fuse.txt).
2060  *
2061  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2062  * requests, they should be finished off immediately.  Locked requests will be
2063  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2064  * requests.  It is possible that some request will finish before we can.  This
2065  * is OK, the request will in that case be removed from the list before we touch
2066  * it.
2067  */
2068 void fuse_abort_conn(struct fuse_conn *fc)
2069 {
2070         struct fuse_iqueue *fiq = &fc->iq;
2071
2072         spin_lock(&fc->lock);
2073         if (fc->connected) {
2074                 struct fuse_dev *fud;
2075                 struct fuse_req *req, *next;
2076                 LIST_HEAD(to_end1);
2077                 LIST_HEAD(to_end2);
2078
2079                 fc->connected = 0;
2080                 fc->blocked = 0;
2081                 fuse_set_initialized(fc);
2082                 list_for_each_entry(fud, &fc->devices, entry) {
2083                         struct fuse_pqueue *fpq = &fud->pq;
2084
2085                         spin_lock(&fpq->lock);
2086                         fpq->connected = 0;
2087                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2088                                 req->out.h.error = -ECONNABORTED;
2089                                 spin_lock(&req->waitq.lock);
2090                                 set_bit(FR_ABORTED, &req->flags);
2091                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2092                                         set_bit(FR_PRIVATE, &req->flags);
2093                                         list_move(&req->list, &to_end1);
2094                                 }
2095                                 spin_unlock(&req->waitq.lock);
2096                         }
2097                         list_splice_init(&fpq->processing, &to_end2);
2098                         spin_unlock(&fpq->lock);
2099                 }
2100                 fc->max_background = UINT_MAX;
2101                 flush_bg_queue(fc);
2102
2103                 spin_lock(&fiq->waitq.lock);
2104                 fiq->connected = 0;
2105                 list_splice_init(&fiq->pending, &to_end2);
2106                 while (forget_pending(fiq))
2107                         kfree(dequeue_forget(fiq, 1, NULL));
2108                 wake_up_all_locked(&fiq->waitq);
2109                 spin_unlock(&fiq->waitq.lock);
2110                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2111                 end_polls(fc);
2112                 wake_up_all(&fc->blocked_waitq);
2113                 spin_unlock(&fc->lock);
2114
2115                 while (!list_empty(&to_end1)) {
2116                         req = list_first_entry(&to_end1, struct fuse_req, list);
2117                         __fuse_get_request(req);
2118                         list_del_init(&req->list);
2119                         request_end(fc, req);
2120                 }
2121                 end_requests(fc, &to_end2);
2122         } else {
2123                 spin_unlock(&fc->lock);
2124         }
2125 }
2126 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2127
2128 int fuse_dev_release(struct inode *inode, struct file *file)
2129 {
2130         struct fuse_dev *fud = fuse_get_dev(file);
2131
2132         if (fud) {
2133                 struct fuse_conn *fc = fud->fc;
2134                 struct fuse_pqueue *fpq = &fud->pq;
2135
2136                 WARN_ON(!list_empty(&fpq->io));
2137                 end_requests(fc, &fpq->processing);
2138                 /* Are we the last open device? */
2139                 if (atomic_dec_and_test(&fc->dev_count)) {
2140                         WARN_ON(fc->iq.fasync != NULL);
2141                         fuse_abort_conn(fc);
2142                 }
2143                 fuse_dev_free(fud);
2144         }
2145         return 0;
2146 }
2147 EXPORT_SYMBOL_GPL(fuse_dev_release);
2148
2149 static int fuse_dev_fasync(int fd, struct file *file, int on)
2150 {
2151         struct fuse_dev *fud = fuse_get_dev(file);
2152
2153         if (!fud)
2154                 return -EPERM;
2155
2156         /* No locking - fasync_helper does its own locking */
2157         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2158 }
2159
2160 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2161 {
2162         struct fuse_dev *fud;
2163
2164         if (new->private_data)
2165                 return -EINVAL;
2166
2167         fud = fuse_dev_alloc(fc);
2168         if (!fud)
2169                 return -ENOMEM;
2170
2171         new->private_data = fud;
2172         atomic_inc(&fc->dev_count);
2173
2174         return 0;
2175 }
2176
2177 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2178                            unsigned long arg)
2179 {
2180         int err = -ENOTTY;
2181
2182         if (cmd == FUSE_DEV_IOC_CLONE) {
2183                 int oldfd;
2184
2185                 err = -EFAULT;
2186                 if (!get_user(oldfd, (__u32 __user *) arg)) {
2187                         struct file *old = fget(oldfd);
2188
2189                         err = -EINVAL;
2190                         if (old) {
2191                                 struct fuse_dev *fud = NULL;
2192
2193                                 /*
2194                                  * Check against file->f_op because CUSE
2195                                  * uses the same ioctl handler.
2196                                  */
2197                                 if (old->f_op == file->f_op &&
2198                                     old->f_cred->user_ns == file->f_cred->user_ns)
2199                                         fud = fuse_get_dev(old);
2200
2201                                 if (fud) {
2202                                         mutex_lock(&fuse_mutex);
2203                                         err = fuse_device_clone(fud->fc, file);
2204                                         mutex_unlock(&fuse_mutex);
2205                                 }
2206                                 fput(old);
2207                         }
2208                 }
2209         }
2210         return err;
2211 }
2212
2213 const struct file_operations fuse_dev_operations = {
2214         .owner          = THIS_MODULE,
2215         .open           = fuse_dev_open,
2216         .llseek         = no_llseek,
2217         .read_iter      = fuse_dev_read,
2218         .splice_read    = fuse_dev_splice_read,
2219         .write_iter     = fuse_dev_write,
2220         .splice_write   = fuse_dev_splice_write,
2221         .poll           = fuse_dev_poll,
2222         .release        = fuse_dev_release,
2223         .fasync         = fuse_dev_fasync,
2224         .unlocked_ioctl = fuse_dev_ioctl,
2225         .compat_ioctl   = fuse_dev_ioctl,
2226 };
2227 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2228
2229 static struct miscdevice fuse_miscdevice = {
2230         .minor = FUSE_MINOR,
2231         .name  = "fuse",
2232         .fops = &fuse_dev_operations,
2233 };
2234
2235 int __init fuse_dev_init(void)
2236 {
2237         int err = -ENOMEM;
2238         fuse_req_cachep = kmem_cache_create("fuse_request",
2239                                             sizeof(struct fuse_req),
2240                                             0, 0, NULL);
2241         if (!fuse_req_cachep)
2242                 goto out;
2243
2244         err = misc_register(&fuse_miscdevice);
2245         if (err)
2246                 goto out_cache_clean;
2247
2248         return 0;
2249
2250  out_cache_clean:
2251         kmem_cache_destroy(fuse_req_cachep);
2252  out:
2253         return err;
2254 }
2255
2256 void fuse_dev_cleanup(void)
2257 {
2258         misc_deregister(&fuse_miscdevice);
2259         kmem_cache_destroy(fuse_req_cachep);
2260 }