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 = buf->ops->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                 cs->offset = off;
 771                 iov_iter_advance(cs->iter, err);
 772         }
 773
 774         return lock_request(cs->req);
 775 }
 776
 777 /* Do as much copy to/from userspace buffer as we can */
 778 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 779 {
 780         unsigned ncpy = min(*size, cs->len);
 781         if (val) {
 782                 void *pgaddr = kmap_atomic(cs->pg);
 783                 void *buf = pgaddr + cs->offset;
 784
 785                 if (cs->write)
 786                         memcpy(buf, *val, ncpy);
 787                 else
 788                         memcpy(*val, buf, ncpy);
 789
 790                 kunmap_atomic(pgaddr);
 791                 *val += ncpy;
 792         }
 793         *size -= ncpy;
 794         cs->len -= ncpy;
 795         cs->offset += ncpy;
 796         return ncpy;
 797 }
 798
 799 static int fuse_check_page(struct page *page)
 800 {
 801         if (page_mapcount(page) ||
 802             page->mapping != NULL ||
 803             page_count(page) != 1 ||
 804             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 805              ~(1 << PG_locked |
 806                1 << PG_referenced |
 807                1 << PG_uptodate |
 808                1 << PG_lru |
 809                1 << PG_active |
 810                1 << PG_reclaim))) {
 811                 printk(KERN_WARNING "fuse: trying to steal weird page\n");
 812                 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);
 813                 return 1;
 814         }
 815         return 0;
 816 }
 817
 818 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 819 {
 820         int err;
 821         struct page *oldpage = *pagep;
 822         struct page *newpage;
 823         struct pipe_buffer *buf = cs->pipebufs;
 824
 825         err = unlock_request(cs->req);
 826         if (err)
 827                 return err;
 828
 829         fuse_copy_finish(cs);
 830
 831         err = buf->ops->confirm(cs->pipe, buf);
 832         if (err)
 833                 return err;
 834
 835         BUG_ON(!cs->nr_segs);
 836         cs->currbuf = buf;
 837         cs->len = buf->len;
 838         cs->pipebufs++;
 839         cs->nr_segs--;
 840
 841         if (cs->len != PAGE_SIZE)
 842                 goto out_fallback;
 843
 844         if (buf->ops->steal(cs->pipe, buf) != 0)
 845                 goto out_fallback;
 846
 847         newpage = buf->page;
 848
 849         if (!PageUptodate(newpage))
 850                 SetPageUptodate(newpage);
 851
 852         ClearPageMappedToDisk(newpage);
 853
 854         if (fuse_check_page(newpage) != 0)
 855                 goto out_fallback_unlock;
 856
 857         /*
 858          * This is a new and locked page, it shouldn't be mapped or
 859          * have any special flags on it
 860          */
 861         if (WARN_ON(page_mapped(oldpage)))
 862                 goto out_fallback_unlock;
 863         if (WARN_ON(page_has_private(oldpage)))
 864                 goto out_fallback_unlock;
 865         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 866                 goto out_fallback_unlock;
 867         if (WARN_ON(PageMlocked(oldpage)))
 868                 goto out_fallback_unlock;
 869
 870         err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 871         if (err) {
 872                 unlock_page(newpage);
 873                 return err;
 874         }
 875
 876         get_page(newpage);
 877
 878         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 879                 lru_cache_add_file(newpage);
 880
 881         err = 0;
 882         spin_lock(&cs->req->waitq.lock);
 883         if (test_bit(FR_ABORTED, &cs->req->flags))
 884                 err = -ENOENT;
 885         else
 886                 *pagep = newpage;
 887         spin_unlock(&cs->req->waitq.lock);
 888
 889         if (err) {
 890                 unlock_page(newpage);
 891                 put_page(newpage);
 892                 return err;
 893         }
 894
 895         unlock_page(oldpage);
 896         put_page(oldpage);
 897         cs->len = 0;
 898
 899         return 0;
 900
 901 out_fallback_unlock:
 902         unlock_page(newpage);
 903 out_fallback:
 904         cs->pg = buf->page;
 905         cs->offset = buf->offset;
 906
 907         err = lock_request(cs->req);
 908         if (err)
 909                 return err;
 910
 911         return 1;
 912 }
 913
 914 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 915                          unsigned offset, unsigned count)
 916 {
 917         struct pipe_buffer *buf;
 918         int err;
 919
 920         if (cs->nr_segs == cs->pipe->buffers)
 921                 return -EIO;
 922
 923         err = unlock_request(cs->req);
 924         if (err)
 925                 return err;
 926
 927         fuse_copy_finish(cs);
 928
 929         buf = cs->pipebufs;
 930         get_page(page);
 931         buf->page = page;
 932         buf->offset = offset;
 933         buf->len = count;
 934
 935         cs->pipebufs++;
 936         cs->nr_segs++;
 937         cs->len = 0;
 938
 939         return 0;
 940 }
 941
 942 /*
 943  * Copy a page in the request to/from the userspace buffer.  Must be
 944  * done atomically
 945  */
 946 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 947                           unsigned offset, unsigned count, int zeroing)
 948 {
 949         int err;
 950         struct page *page = *pagep;
 951
 952         if (page && zeroing && count < PAGE_SIZE)
 953                 clear_highpage(page);
 954
 955         while (count) {
 956                 if (cs->write && cs->pipebufs && page) {
 957                         return fuse_ref_page(cs, page, offset, count);
 958                 } else if (!cs->len) {
 959                         if (cs->move_pages && page &&
 960                             offset == 0 && count == PAGE_SIZE) {
 961                                 err = fuse_try_move_page(cs, pagep);
 962                                 if (err <= 0)
 963                                         return err;
 964                         } else {
 965                                 err = fuse_copy_fill(cs);
 966                                 if (err)
 967                                         return err;
 968                         }
 969                 }
 970                 if (page) {
 971                         void *mapaddr = kmap_atomic(page);
 972                         void *buf = mapaddr + offset;
 973                         offset += fuse_copy_do(cs, &buf, &count);
 974                         kunmap_atomic(mapaddr);
 975                 } else
 976                         offset += fuse_copy_do(cs, NULL, &count);
 977         }
 978         if (page && !cs->write)
 979                 flush_dcache_page(page);
 980         return 0;
 981 }
 982
 983 /* Copy pages in the request to/from userspace buffer */
 984 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 985                            int zeroing)
 986 {
 987         unsigned i;
 988         struct fuse_req *req = cs->req;
 989
 990         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
 991                 int err;
 992                 unsigned offset = req->page_descs[i].offset;
 993                 unsigned count = min(nbytes, req->page_descs[i].length);
 994
 995                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
 996                                      zeroing);
 997                 if (err)
 998                         return err;
 999
1000                 nbytes -= count;
1001         }
1002         return 0;
1003 }
1004
1005 /* Copy a single argument in the request to/from userspace buffer */
1006 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1007 {
1008         while (size) {
1009                 if (!cs->len) {
1010                         int err = fuse_copy_fill(cs);
1011                         if (err)
1012                                 return err;
1013                 }
1014                 fuse_copy_do(cs, &val, &size);
1015         }
1016         return 0;
1017 }
1018
1019 /* Copy request arguments to/from userspace buffer */
1020 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1021                           unsigned argpages, struct fuse_arg *args,
1022                           int zeroing)
1023 {
1024         int err = 0;
1025         unsigned i;
1026
1027         for (i = 0; !err && i < numargs; i++)  {
1028                 struct fuse_arg *arg = &args[i];
1029                 if (i == numargs - 1 && argpages)
1030                         err = fuse_copy_pages(cs, arg->size, zeroing);
1031                 else
1032                         err = fuse_copy_one(cs, arg->value, arg->size);
1033         }
1034         return err;
1035 }
1036
1037 static int forget_pending(struct fuse_iqueue *fiq)
1038 {
1039         return fiq->forget_list_head.next != NULL;
1040 }
1041
1042 static int request_pending(struct fuse_iqueue *fiq)
1043 {
1044         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1045                 forget_pending(fiq);
1046 }
1047
1048 /*
1049  * Transfer an interrupt request to userspace
1050  *
1051  * Unlike other requests this is assembled on demand, without a need
1052  * to allocate a separate fuse_req structure.
1053  *
1054  * Called with fiq->waitq.lock held, releases it
1055  */
1056 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1057                                struct fuse_copy_state *cs,
1058                                size_t nbytes, struct fuse_req *req)
1059 __releases(fiq->waitq.lock)
1060 {
1061         struct fuse_in_header ih;
1062         struct fuse_interrupt_in arg;
1063         unsigned reqsize = sizeof(ih) + sizeof(arg);
1064         int err;
1065
1066         list_del_init(&req->intr_entry);
1067         req->intr_unique = fuse_get_unique(fiq);
1068         memset(&ih, 0, sizeof(ih));
1069         memset(&arg, 0, sizeof(arg));
1070         ih.len = reqsize;
1071         ih.opcode = FUSE_INTERRUPT;
1072         ih.unique = req->intr_unique;
1073         arg.unique = req->in.h.unique;
1074
1075         spin_unlock(&fiq->waitq.lock);
1076         if (nbytes < reqsize)
1077                 return -EINVAL;
1078
1079         err = fuse_copy_one(cs, &ih, sizeof(ih));
1080         if (!err)
1081                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1082         fuse_copy_finish(cs);
1083
1084         return err ? err : reqsize;
1085 }
1086
1087 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1088                                                unsigned max,
1089                                                unsigned *countp)
1090 {
1091         struct fuse_forget_link *head = fiq->forget_list_head.next;
1092         struct fuse_forget_link **newhead = &head;
1093         unsigned count;
1094
1095         for (count = 0; *newhead != NULL && count < max; count++)
1096                 newhead = &(*newhead)->next;
1097
1098         fiq->forget_list_head.next = *newhead;
1099         *newhead = NULL;
1100         if (fiq->forget_list_head.next == NULL)
1101                 fiq->forget_list_tail = &fiq->forget_list_head;
1102
1103         if (countp != NULL)
1104                 *countp = count;
1105
1106         return head;
1107 }
1108
1109 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1110                                    struct fuse_copy_state *cs,
1111                                    size_t nbytes)
1112 __releases(fiq->waitq.lock)
1113 {
1114         int err;
1115         struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1116         struct fuse_forget_in arg = {
1117                 .nlookup = forget->forget_one.nlookup,
1118         };
1119         struct fuse_in_header ih = {
1120                 .opcode = FUSE_FORGET,
1121                 .nodeid = forget->forget_one.nodeid,
1122                 .unique = fuse_get_unique(fiq),
1123                 .len = sizeof(ih) + sizeof(arg),
1124         };
1125
1126         spin_unlock(&fiq->waitq.lock);
1127         kfree(forget);
1128         if (nbytes < ih.len)
1129                 return -EINVAL;
1130
1131         err = fuse_copy_one(cs, &ih, sizeof(ih));
1132         if (!err)
1133                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1134         fuse_copy_finish(cs);
1135
1136         if (err)
1137                 return err;
1138
1139         return ih.len;
1140 }
1141
1142 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1143                                    struct fuse_copy_state *cs, size_t nbytes)
1144 __releases(fiq->waitq.lock)
1145 {
1146         int err;
1147         unsigned max_forgets;
1148         unsigned count;
1149         struct fuse_forget_link *head;
1150         struct fuse_batch_forget_in arg = { .count = 0 };
1151         struct fuse_in_header ih = {
1152                 .opcode = FUSE_BATCH_FORGET,
1153                 .unique = fuse_get_unique(fiq),
1154                 .len = sizeof(ih) + sizeof(arg),
1155         };
1156
1157         if (nbytes < ih.len) {
1158                 spin_unlock(&fiq->waitq.lock);
1159                 return -EINVAL;
1160         }
1161
1162         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1163         head = dequeue_forget(fiq, max_forgets, &count);
1164         spin_unlock(&fiq->waitq.lock);
1165
1166         arg.count = count;
1167         ih.len += count * sizeof(struct fuse_forget_one);
1168         err = fuse_copy_one(cs, &ih, sizeof(ih));
1169         if (!err)
1170                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1171
1172         while (head) {
1173                 struct fuse_forget_link *forget = head;
1174
1175                 if (!err) {
1176                         err = fuse_copy_one(cs, &forget->forget_one,
1177                                             sizeof(forget->forget_one));
1178                 }
1179                 head = forget->next;
1180                 kfree(forget);
1181         }
1182
1183         fuse_copy_finish(cs);
1184
1185         if (err)
1186                 return err;
1187
1188         return ih.len;
1189 }
1190
1191 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1192                             struct fuse_copy_state *cs,
1193                             size_t nbytes)
1194 __releases(fiq->waitq.lock)
1195 {
1196         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1197                 return fuse_read_single_forget(fiq, cs, nbytes);
1198         else
1199                 return fuse_read_batch_forget(fiq, cs, nbytes);
1200 }
1201
1202 /*
1203  * Read a single request into the userspace filesystem's buffer.  This
1204  * function waits until a request is available, then removes it from
1205  * the pending list and copies request data to userspace buffer.  If
1206  * no reply is needed (FORGET) or request has been aborted or there
1207  * was an error during the copying then it's finished by calling
1208  * request_end().  Otherwise add it to the processing list, and set
1209  * the 'sent' flag.
1210  */
1211 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1212                                 struct fuse_copy_state *cs, size_t nbytes)
1213 {
1214         ssize_t err;
1215         struct fuse_conn *fc = fud->fc;
1216         struct fuse_iqueue *fiq = &fc->iq;
1217         struct fuse_pqueue *fpq = &fud->pq;
1218         struct fuse_req *req;
1219         struct fuse_in *in;
1220         unsigned reqsize;
1221
1222  restart:
1223         spin_lock(&fiq->waitq.lock);
1224         err = -EAGAIN;
1225         if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1226             !request_pending(fiq))
1227                 goto err_unlock;
1228
1229         err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1230                                 !fiq->connected || request_pending(fiq));
1231         if (err)
1232                 goto err_unlock;
1233
1234         err = -ENODEV;
1235         if (!fiq->connected)
1236                 goto err_unlock;
1237
1238         if (!list_empty(&fiq->interrupts)) {
1239                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1240                                  intr_entry);
1241                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1242         }
1243
1244         if (forget_pending(fiq)) {
1245                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1246                         return fuse_read_forget(fc, fiq, cs, nbytes);
1247
1248                 if (fiq->forget_batch <= -8)
1249                         fiq->forget_batch = 16;
1250         }
1251
1252         req = list_entry(fiq->pending.next, struct fuse_req, list);
1253         clear_bit(FR_PENDING, &req->flags);
1254         list_del_init(&req->list);
1255         spin_unlock(&fiq->waitq.lock);
1256
1257         in = &req->in;
1258         reqsize = in->h.len;
1259         /* If request is too large, reply with an error and restart the read */
1260         if (nbytes < reqsize) {
1261                 req->out.h.error = -EIO;
1262                 /* SETXATTR is special, since it may contain too large data */
1263                 if (in->h.opcode == FUSE_SETXATTR)
1264                         req->out.h.error = -E2BIG;
1265                 request_end(fc, req);
1266                 goto restart;
1267         }
1268         spin_lock(&fpq->lock);
1269         list_add(&req->list, &fpq->io);
1270         spin_unlock(&fpq->lock);
1271         cs->req = req;
1272         err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1273         if (!err)
1274                 err = fuse_copy_args(cs, in->numargs, in->argpages,
1275                                      (struct fuse_arg *) in->args, 0);
1276         fuse_copy_finish(cs);
1277         spin_lock(&fpq->lock);
1278         clear_bit(FR_LOCKED, &req->flags);
1279         if (!fpq->connected) {
1280                 err = -ENODEV;
1281                 goto out_end;
1282         }
1283         if (err) {
1284                 req->out.h.error = -EIO;
1285                 goto out_end;
1286         }
1287         if (!test_bit(FR_ISREPLY, &req->flags)) {
1288                 err = reqsize;
1289                 goto out_end;
1290         }
1291         list_move_tail(&req->list, &fpq->processing);
1292         spin_unlock(&fpq->lock);
1293         set_bit(FR_SENT, &req->flags);
1294         /* matches barrier in request_wait_answer() */
1295         smp_mb__after_atomic();
1296         if (test_bit(FR_INTERRUPTED, &req->flags))
1297                 queue_interrupt(fiq, req);
1298
1299         return reqsize;
1300
1301 out_end:
1302         if (!test_bit(FR_PRIVATE, &req->flags))
1303                 list_del_init(&req->list);
1304         spin_unlock(&fpq->lock);
1305         request_end(fc, req);
1306         return err;
1307
1308  err_unlock:
1309         spin_unlock(&fiq->waitq.lock);
1310         return err;
1311 }
1312
1313 static int fuse_dev_open(struct inode *inode, struct file *file)
1314 {
1315         /*
1316          * The fuse device's file's private_data is used to hold
1317          * the fuse_conn(ection) when it is mounted, and is used to
1318          * keep track of whether the file has been mounted already.
1319          */
1320         file->private_data = NULL;
1321         return 0;
1322 }
1323
1324 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1325 {
1326         struct fuse_copy_state cs;
1327         struct file *file = iocb->ki_filp;
1328         struct fuse_dev *fud = fuse_get_dev(file);
1329
1330         if (!fud)
1331                 return -EPERM;
1332
1333         if (!iter_is_iovec(to))
1334                 return -EINVAL;
1335
1336         fuse_copy_init(&cs, 1, to);
1337
1338         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1339 }
1340
1341 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1342                                     struct pipe_inode_info *pipe,
1343                                     size_t len, unsigned int flags)
1344 {
1345         int ret;
1346         int page_nr = 0;
1347         int do_wakeup = 0;
1348         struct pipe_buffer *bufs;
1349         struct fuse_copy_state cs;
1350         struct fuse_dev *fud = fuse_get_dev(in);
1351
1352         if (!fud)
1353                 return -EPERM;
1354
1355         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1356         if (!bufs)
1357                 return -ENOMEM;
1358
1359         fuse_copy_init(&cs, 1, NULL);
1360         cs.pipebufs = bufs;
1361         cs.pipe = pipe;
1362         ret = fuse_dev_do_read(fud, in, &cs, len);
1363         if (ret < 0)
1364                 goto out;
1365
1366         ret = 0;
1367         pipe_lock(pipe);
1368
1369         if (!pipe->readers) {
1370                 send_sig(SIGPIPE, current, 0);
1371                 if (!ret)
1372                         ret = -EPIPE;
1373                 goto out_unlock;
1374         }
1375
1376         if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1377                 ret = -EIO;
1378                 goto out_unlock;
1379         }
1380
1381         while (page_nr < cs.nr_segs) {
1382                 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1383                 struct pipe_buffer *buf = pipe->bufs + newbuf;
1384
1385                 buf->page = bufs[page_nr].page;
1386                 buf->offset = bufs[page_nr].offset;
1387                 buf->len = bufs[page_nr].len;
1388                 /*
1389                  * Need to be careful about this.  Having buf->ops in module
1390                  * code can Oops if the buffer persists after module unload.
1391                  */
1392                 buf->ops = &nosteal_pipe_buf_ops;
1393
1394                 pipe->nrbufs++;
1395                 page_nr++;
1396                 ret += buf->len;
1397
1398                 if (pipe->files)
1399                         do_wakeup = 1;
1400         }
1401
1402 out_unlock:
1403         pipe_unlock(pipe);
1404
1405         if (do_wakeup) {
1406                 smp_mb();
1407                 if (waitqueue_active(&pipe->wait))
1408                         wake_up_interruptible(&pipe->wait);
1409                 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1410         }
1411
1412 out:
1413         for (; page_nr < cs.nr_segs; page_nr++)
1414                 put_page(bufs[page_nr].page);
1415
1416         kfree(bufs);
1417         return ret;
1418 }
1419
1420 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1421                             struct fuse_copy_state *cs)
1422 {
1423         struct fuse_notify_poll_wakeup_out outarg;
1424         int err = -EINVAL;
1425
1426         if (size != sizeof(outarg))
1427                 goto err;
1428
1429         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1430         if (err)
1431                 goto err;
1432
1433         fuse_copy_finish(cs);
1434         return fuse_notify_poll_wakeup(fc, &outarg);
1435
1436 err:
1437         fuse_copy_finish(cs);
1438         return err;
1439 }
1440
1441 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1442                                    struct fuse_copy_state *cs)
1443 {
1444         struct fuse_notify_inval_inode_out outarg;
1445         int err = -EINVAL;
1446
1447         if (size != sizeof(outarg))
1448                 goto err;
1449
1450         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1451         if (err)
1452                 goto err;
1453         fuse_copy_finish(cs);
1454
1455         down_read(&fc->killsb);
1456         err = -ENOENT;
1457         if (fc->sb) {
1458                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1459                                                outarg.off, outarg.len);
1460         }
1461         up_read(&fc->killsb);
1462         return err;
1463
1464 err:
1465         fuse_copy_finish(cs);
1466         return err;
1467 }
1468
1469 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1470                                    struct fuse_copy_state *cs)
1471 {
1472         struct fuse_notify_inval_entry_out outarg;
1473         int err = -ENOMEM;
1474         char *buf;
1475         struct qstr name;
1476
1477         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1478         if (!buf)
1479                 goto err;
1480
1481         err = -EINVAL;
1482         if (size < sizeof(outarg))
1483                 goto err;
1484
1485         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1486         if (err)
1487                 goto err;
1488
1489         err = -ENAMETOOLONG;
1490         if (outarg.namelen > FUSE_NAME_MAX)
1491                 goto err;
1492
1493         err = -EINVAL;
1494         if (size != sizeof(outarg) + outarg.namelen + 1)
1495                 goto err;
1496
1497         name.name = buf;
1498         name.len = outarg.namelen;
1499         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1500         if (err)
1501                 goto err;
1502         fuse_copy_finish(cs);
1503         buf[outarg.namelen] = 0;
1504
1505         down_read(&fc->killsb);
1506         err = -ENOENT;
1507         if (fc->sb)
1508                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1509         up_read(&fc->killsb);
1510         kfree(buf);
1511         return err;
1512
1513 err:
1514         kfree(buf);
1515         fuse_copy_finish(cs);
1516         return err;
1517 }
1518
1519 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1520                               struct fuse_copy_state *cs)
1521 {
1522         struct fuse_notify_delete_out outarg;
1523         int err = -ENOMEM;
1524         char *buf;
1525         struct qstr name;
1526
1527         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1528         if (!buf)
1529                 goto err;
1530
1531         err = -EINVAL;
1532         if (size < sizeof(outarg))
1533                 goto err;
1534
1535         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1536         if (err)
1537                 goto err;
1538
1539         err = -ENAMETOOLONG;
1540         if (outarg.namelen > FUSE_NAME_MAX)
1541                 goto err;
1542
1543         err = -EINVAL;
1544         if (size != sizeof(outarg) + outarg.namelen + 1)
1545                 goto err;
1546
1547         name.name = buf;
1548         name.len = outarg.namelen;
1549         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1550         if (err)
1551                 goto err;
1552         fuse_copy_finish(cs);
1553         buf[outarg.namelen] = 0;
1554
1555         down_read(&fc->killsb);
1556         err = -ENOENT;
1557         if (fc->sb)
1558                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1559                                                outarg.child, &name);
1560         up_read(&fc->killsb);
1561         kfree(buf);
1562         return err;
1563
1564 err:
1565         kfree(buf);
1566         fuse_copy_finish(cs);
1567         return err;
1568 }
1569
1570 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1571                              struct fuse_copy_state *cs)
1572 {
1573         struct fuse_notify_store_out outarg;
1574         struct inode *inode;
1575         struct address_space *mapping;
1576         u64 nodeid;
1577         int err;
1578         pgoff_t index;
1579         unsigned int offset;
1580         unsigned int num;
1581         loff_t file_size;
1582         loff_t end;
1583
1584         err = -EINVAL;
1585         if (size < sizeof(outarg))
1586                 goto out_finish;
1587
1588         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1589         if (err)
1590                 goto out_finish;
1591
1592         err = -EINVAL;
1593         if (size - sizeof(outarg) != outarg.size)
1594                 goto out_finish;
1595
1596         nodeid = outarg.nodeid;
1597
1598         down_read(&fc->killsb);
1599
1600         err = -ENOENT;
1601         if (!fc->sb)
1602                 goto out_up_killsb;
1603
1604         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1605         if (!inode)
1606                 goto out_up_killsb;
1607
1608         mapping = inode->i_mapping;
1609         index = outarg.offset >> PAGE_SHIFT;
1610         offset = outarg.offset & ~PAGE_MASK;
1611         file_size = i_size_read(inode);
1612         end = outarg.offset + outarg.size;
1613         if (end > file_size) {
1614                 file_size = end;
1615                 fuse_write_update_size(inode, file_size);
1616         }
1617
1618         num = outarg.size;
1619         while (num) {
1620                 struct page *page;
1621                 unsigned int this_num;
1622
1623                 err = -ENOMEM;
1624                 page = find_or_create_page(mapping, index,
1625                                            mapping_gfp_mask(mapping));
1626                 if (!page)
1627                         goto out_iput;
1628
1629                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1630                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1631                 if (!err && offset == 0 &&
1632                     (this_num == PAGE_SIZE || file_size == end))
1633                         SetPageUptodate(page);
1634                 unlock_page(page);
1635                 put_page(page);
1636
1637                 if (err)
1638                         goto out_iput;
1639
1640                 num -= this_num;
1641                 offset = 0;
1642                 index++;
1643         }
1644
1645         err = 0;
1646
1647 out_iput:
1648         iput(inode);
1649 out_up_killsb:
1650         up_read(&fc->killsb);
1651 out_finish:
1652         fuse_copy_finish(cs);
1653         return err;
1654 }
1655
1656 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1657 {
1658         release_pages(req->pages, req->num_pages, false);
1659 }
1660
1661 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1662                          struct fuse_notify_retrieve_out *outarg)
1663 {
1664         int err;
1665         struct address_space *mapping = inode->i_mapping;
1666         struct fuse_req *req;
1667         pgoff_t index;
1668         loff_t file_size;
1669         unsigned int num;
1670         unsigned int offset;
1671         size_t total_len = 0;
1672         int num_pages;
1673
1674         offset = outarg->offset & ~PAGE_MASK;
1675         file_size = i_size_read(inode);
1676
1677         num = outarg->size;
1678         if (outarg->offset > file_size)
1679                 num = 0;
1680         else if (outarg->offset + num > file_size)
1681                 num = file_size - outarg->offset;
1682
1683         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1684         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1685
1686         req = fuse_get_req(fc, num_pages);
1687         if (IS_ERR(req))
1688                 return PTR_ERR(req);
1689
1690         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1691         req->in.h.nodeid = outarg->nodeid;
1692         req->in.numargs = 2;
1693         req->in.argpages = 1;
1694         req->page_descs[0].offset = offset;
1695         req->end = fuse_retrieve_end;
1696
1697         index = outarg->offset >> PAGE_SHIFT;
1698
1699         while (num && req->num_pages < num_pages) {
1700                 struct page *page;
1701                 unsigned int this_num;
1702
1703                 page = find_get_page(mapping, index);
1704                 if (!page)
1705                         break;
1706
1707                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1708                 req->pages[req->num_pages] = page;
1709                 req->page_descs[req->num_pages].length = this_num;
1710                 req->num_pages++;
1711
1712                 offset = 0;
1713                 num -= this_num;
1714                 total_len += this_num;
1715                 index++;
1716         }
1717         req->misc.retrieve_in.offset = outarg->offset;
1718         req->misc.retrieve_in.size = total_len;
1719         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1720         req->in.args[0].value = &req->misc.retrieve_in;
1721         req->in.args[1].size = total_len;
1722
1723         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1724         if (err)
1725                 fuse_retrieve_end(fc, req);
1726
1727         return err;
1728 }
1729
1730 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1731                                 struct fuse_copy_state *cs)
1732 {
1733         struct fuse_notify_retrieve_out outarg;
1734         struct inode *inode;
1735         int err;
1736
1737         err = -EINVAL;
1738         if (size != sizeof(outarg))
1739                 goto copy_finish;
1740
1741         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1742         if (err)
1743                 goto copy_finish;
1744
1745         fuse_copy_finish(cs);
1746
1747         down_read(&fc->killsb);
1748         err = -ENOENT;
1749         if (fc->sb) {
1750                 u64 nodeid = outarg.nodeid;
1751
1752                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1753                 if (inode) {
1754                         err = fuse_retrieve(fc, inode, &outarg);
1755                         iput(inode);
1756                 }
1757         }
1758         up_read(&fc->killsb);
1759
1760         return err;
1761
1762 copy_finish:
1763         fuse_copy_finish(cs);
1764         return err;
1765 }
1766
1767 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1768                        unsigned int size, struct fuse_copy_state *cs)
1769 {
1770         /* Don't try to move pages (yet) */
1771         cs->move_pages = 0;
1772
1773         switch (code) {
1774         case FUSE_NOTIFY_POLL:
1775                 return fuse_notify_poll(fc, size, cs);
1776
1777         case FUSE_NOTIFY_INVAL_INODE:
1778                 return fuse_notify_inval_inode(fc, size, cs);
1779
1780         case FUSE_NOTIFY_INVAL_ENTRY:
1781                 return fuse_notify_inval_entry(fc, size, cs);
1782
1783         case FUSE_NOTIFY_STORE:
1784                 return fuse_notify_store(fc, size, cs);
1785
1786         case FUSE_NOTIFY_RETRIEVE:
1787                 return fuse_notify_retrieve(fc, size, cs);
1788
1789         case FUSE_NOTIFY_DELETE:
1790                 return fuse_notify_delete(fc, size, cs);
1791
1792         default:
1793                 fuse_copy_finish(cs);
1794                 return -EINVAL;
1795         }
1796 }
1797
1798 /* Look up request on processing list by unique ID */
1799 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1800 {
1801         struct fuse_req *req;
1802
1803         list_for_each_entry(req, &fpq->processing, list) {
1804                 if (req->in.h.unique == unique || req->intr_unique == unique)
1805                         return req;
1806         }
1807         return NULL;
1808 }
1809
1810 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1811                          unsigned nbytes)
1812 {
1813         unsigned reqsize = sizeof(struct fuse_out_header);
1814
1815         if (out->h.error)
1816                 return nbytes != reqsize ? -EINVAL : 0;
1817
1818         reqsize += len_args(out->numargs, out->args);
1819
1820         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1821                 return -EINVAL;
1822         else if (reqsize > nbytes) {
1823                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1824                 unsigned diffsize = reqsize - nbytes;
1825                 if (diffsize > lastarg->size)
1826                         return -EINVAL;
1827                 lastarg->size -= diffsize;
1828         }
1829         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1830                               out->page_zeroing);
1831 }
1832
1833 /*
1834  * Write a single reply to a request.  First the header is copied from
1835  * the write buffer.  The request is then searched on the processing
1836  * list by the unique ID found in the header.  If found, then remove
1837  * it from the list and copy the rest of the buffer to the request.
1838  * The request is finished by calling request_end()
1839  */
1840 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1841                                  struct fuse_copy_state *cs, size_t nbytes)
1842 {
1843         int err;
1844         struct fuse_conn *fc = fud->fc;
1845         struct fuse_pqueue *fpq = &fud->pq;
1846         struct fuse_req *req;
1847         struct fuse_out_header oh;
1848
1849         if (nbytes < sizeof(struct fuse_out_header))
1850                 return -EINVAL;
1851
1852         err = fuse_copy_one(cs, &oh, sizeof(oh));
1853         if (err)
1854                 goto err_finish;
1855
1856         err = -EINVAL;
1857         if (oh.len != nbytes)
1858                 goto err_finish;
1859
1860         /*
1861          * Zero oh.unique indicates unsolicited notification message
1862          * and error contains notification code.
1863          */
1864         if (!oh.unique) {
1865                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1866                 return err ? err : nbytes;
1867         }
1868
1869         err = -EINVAL;
1870         if (oh.error <= -1000 || oh.error > 0)
1871                 goto err_finish;
1872
1873         spin_lock(&fpq->lock);
1874         err = -ENOENT;
1875         if (!fpq->connected)
1876                 goto err_unlock_pq;
1877
1878         req = request_find(fpq, oh.unique);
1879         if (!req)
1880                 goto err_unlock_pq;
1881
1882         /* Is it an interrupt reply? */
1883         if (req->intr_unique == oh.unique) {
1884                 spin_unlock(&fpq->lock);
1885
1886                 err = -EINVAL;
1887                 if (nbytes != sizeof(struct fuse_out_header))
1888                         goto err_finish;
1889
1890                 if (oh.error == -ENOSYS)
1891                         fc->no_interrupt = 1;
1892                 else if (oh.error == -EAGAIN)
1893                         queue_interrupt(&fc->iq, req);
1894
1895                 fuse_copy_finish(cs);
1896                 return nbytes;
1897         }
1898
1899         clear_bit(FR_SENT, &req->flags);
1900         list_move(&req->list, &fpq->io);
1901         req->out.h = oh;
1902         set_bit(FR_LOCKED, &req->flags);
1903         spin_unlock(&fpq->lock);
1904         cs->req = req;
1905         if (!req->out.page_replace)
1906                 cs->move_pages = 0;
1907
1908         err = copy_out_args(cs, &req->out, nbytes);
1909         fuse_copy_finish(cs);
1910
1911         spin_lock(&fpq->lock);
1912         clear_bit(FR_LOCKED, &req->flags);
1913         if (!fpq->connected)
1914                 err = -ENOENT;
1915         else if (err)
1916                 req->out.h.error = -EIO;
1917         if (!test_bit(FR_PRIVATE, &req->flags))
1918                 list_del_init(&req->list);
1919         spin_unlock(&fpq->lock);
1920
1921         request_end(fc, req);
1922
1923         return err ? err : nbytes;
1924
1925  err_unlock_pq:
1926         spin_unlock(&fpq->lock);
1927  err_finish:
1928         fuse_copy_finish(cs);
1929         return err;
1930 }
1931
1932 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1933 {
1934         struct fuse_copy_state cs;
1935         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1936
1937         if (!fud)
1938                 return -EPERM;
1939
1940         if (!iter_is_iovec(from))
1941                 return -EINVAL;
1942
1943         fuse_copy_init(&cs, 0, from);
1944
1945         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1946 }
1947
1948 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1949                                      struct file *out, loff_t *ppos,
1950                                      size_t len, unsigned int flags)
1951 {
1952         unsigned nbuf;
1953         unsigned idx;
1954         struct pipe_buffer *bufs;
1955         struct fuse_copy_state cs;
1956         struct fuse_dev *fud;
1957         size_t rem;
1958         ssize_t ret;
1959
1960         fud = fuse_get_dev(out);
1961         if (!fud)
1962                 return -EPERM;
1963
1964         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1965         if (!bufs)
1966                 return -ENOMEM;
1967
1968         pipe_lock(pipe);
1969         nbuf = 0;
1970         rem = 0;
1971         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1972                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1973
1974         ret = -EINVAL;
1975         if (rem < len) {
1976                 pipe_unlock(pipe);
1977                 goto out;
1978         }
1979
1980         rem = len;
1981         while (rem) {
1982                 struct pipe_buffer *ibuf;
1983                 struct pipe_buffer *obuf;
1984
1985                 BUG_ON(nbuf >= pipe->buffers);
1986                 BUG_ON(!pipe->nrbufs);
1987                 ibuf = &pipe->bufs[pipe->curbuf];
1988                 obuf = &bufs[nbuf];
1989
1990                 if (rem >= ibuf->len) {
1991                         *obuf = *ibuf;
1992                         ibuf->ops = NULL;
1993                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1994                         pipe->nrbufs--;
1995                 } else {
1996                         ibuf->ops->get(pipe, ibuf);
1997                         *obuf = *ibuf;
1998                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1999                         obuf->len = rem;
2000                         ibuf->offset += obuf->len;
2001                         ibuf->len -= obuf->len;
2002                 }
2003                 nbuf++;
2004                 rem -= obuf->len;
2005         }
2006         pipe_unlock(pipe);
2007
2008         fuse_copy_init(&cs, 0, NULL);
2009         cs.pipebufs = bufs;
2010         cs.nr_segs = nbuf;
2011         cs.pipe = pipe;
2012
2013         if (flags & SPLICE_F_MOVE)
2014                 cs.move_pages = 1;
2015
2016         ret = fuse_dev_do_write(fud, &cs, len);
2017
2018         for (idx = 0; idx < nbuf; idx++) {
2019                 struct pipe_buffer *buf = &bufs[idx];
2020                 buf->ops->release(pipe, buf);
2021         }
2022 out:
2023         kfree(bufs);
2024         return ret;
2025 }
2026
2027 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2028 {
2029         unsigned mask = POLLOUT | POLLWRNORM;
2030         struct fuse_iqueue *fiq;
2031         struct fuse_dev *fud = fuse_get_dev(file);
2032
2033         if (!fud)
2034                 return POLLERR;
2035
2036         fiq = &fud->fc->iq;
2037         poll_wait(file, &fiq->waitq, wait);
2038
2039         spin_lock(&fiq->waitq.lock);
2040         if (!fiq->connected)
2041                 mask = POLLERR;
2042         else if (request_pending(fiq))
2043                 mask |= POLLIN | POLLRDNORM;
2044         spin_unlock(&fiq->waitq.lock);
2045
2046         return mask;
2047 }
2048
2049 /*
2050  * Abort all requests on the given list (pending or processing)
2051  *
2052  * This function releases and reacquires fc->lock
2053  */
2054 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2055 {
2056         while (!list_empty(head)) {
2057                 struct fuse_req *req;
2058                 req = list_entry(head->next, struct fuse_req, list);
2059                 req->out.h.error = -ECONNABORTED;
2060                 clear_bit(FR_PENDING, &req->flags);
2061                 clear_bit(FR_SENT, &req->flags);
2062                 list_del_init(&req->list);
2063                 request_end(fc, req);
2064         }
2065 }
2066
2067 static void end_polls(struct fuse_conn *fc)
2068 {
2069         struct rb_node *p;
2070
2071         p = rb_first(&fc->polled_files);
2072
2073         while (p) {
2074                 struct fuse_file *ff;
2075                 ff = rb_entry(p, struct fuse_file, polled_node);
2076                 wake_up_interruptible_all(&ff->poll_wait);
2077
2078                 p = rb_next(p);
2079         }
2080 }
2081
2082 /*
2083  * Abort all requests.
2084  *
2085  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2086  * filesystem.
2087  *
2088  * The same effect is usually achievable through killing the filesystem daemon
2089  * and all users of the filesystem.  The exception is the combination of an
2090  * asynchronous request and the tricky deadlock (see
2091  * Documentation/filesystems/fuse.txt).
2092  *
2093  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2094  * requests, they should be finished off immediately.  Locked requests will be
2095  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2096  * requests.  It is possible that some request will finish before we can.  This
2097  * is OK, the request will in that case be removed from the list before we touch
2098  * it.
2099  */
2100 void fuse_abort_conn(struct fuse_conn *fc)
2101 {
2102         struct fuse_iqueue *fiq = &fc->iq;
2103
2104         spin_lock(&fc->lock);
2105         if (fc->connected) {
2106                 struct fuse_dev *fud;
2107                 struct fuse_req *req, *next;
2108                 LIST_HEAD(to_end1);
2109                 LIST_HEAD(to_end2);
2110
2111                 fc->connected = 0;
2112                 fc->blocked = 0;
2113                 fuse_set_initialized(fc);
2114                 list_for_each_entry(fud, &fc->devices, entry) {
2115                         struct fuse_pqueue *fpq = &fud->pq;
2116
2117                         spin_lock(&fpq->lock);
2118                         fpq->connected = 0;
2119                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2120                                 req->out.h.error = -ECONNABORTED;
2121                                 spin_lock(&req->waitq.lock);
2122                                 set_bit(FR_ABORTED, &req->flags);
2123                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2124                                         set_bit(FR_PRIVATE, &req->flags);
2125                                         list_move(&req->list, &to_end1);
2126                                 }
2127                                 spin_unlock(&req->waitq.lock);
2128                         }
2129                         list_splice_init(&fpq->processing, &to_end2);
2130                         spin_unlock(&fpq->lock);
2131                 }
2132                 fc->max_background = UINT_MAX;
2133                 flush_bg_queue(fc);
2134
2135                 spin_lock(&fiq->waitq.lock);
2136                 fiq->connected = 0;
2137                 list_splice_init(&fiq->pending, &to_end2);
2138                 while (forget_pending(fiq))
2139                         kfree(dequeue_forget(fiq, 1, NULL));
2140                 wake_up_all_locked(&fiq->waitq);
2141                 spin_unlock(&fiq->waitq.lock);
2142                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2143                 end_polls(fc);
2144                 wake_up_all(&fc->blocked_waitq);
2145                 spin_unlock(&fc->lock);
2146
2147                 while (!list_empty(&to_end1)) {
2148                         req = list_first_entry(&to_end1, struct fuse_req, list);
2149                         __fuse_get_request(req);
2150                         list_del_init(&req->list);
2151                         request_end(fc, req);
2152                 }
2153                 end_requests(fc, &to_end2);
2154         } else {
2155                 spin_unlock(&fc->lock);
2156         }
2157 }
2158 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2159
2160 int fuse_dev_release(struct inode *inode, struct file *file)
2161 {
2162         struct fuse_dev *fud = fuse_get_dev(file);
2163
2164         if (fud) {
2165                 struct fuse_conn *fc = fud->fc;
2166                 struct fuse_pqueue *fpq = &fud->pq;
2167
2168                 WARN_ON(!list_empty(&fpq->io));
2169                 end_requests(fc, &fpq->processing);
2170                 /* Are we the last open device? */
2171                 if (atomic_dec_and_test(&fc->dev_count)) {
2172                         WARN_ON(fc->iq.fasync != NULL);
2173                         fuse_abort_conn(fc);
2174                 }
2175                 fuse_dev_free(fud);
2176         }
2177         return 0;
2178 }
2179 EXPORT_SYMBOL_GPL(fuse_dev_release);
2180
2181 static int fuse_dev_fasync(int fd, struct file *file, int on)
2182 {
2183         struct fuse_dev *fud = fuse_get_dev(file);
2184
2185         if (!fud)
2186                 return -EPERM;
2187
2188         /* No locking - fasync_helper does its own locking */
2189         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2190 }
2191
2192 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2193 {
2194         struct fuse_dev *fud;
2195
2196         if (new->private_data)
2197                 return -EINVAL;
2198
2199         fud = fuse_dev_alloc(fc);
2200         if (!fud)
2201                 return -ENOMEM;
2202
2203         new->private_data = fud;
2204         atomic_inc(&fc->dev_count);
2205
2206         return 0;
2207 }
2208
2209 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2210                            unsigned long arg)
2211 {
2212         int err = -ENOTTY;
2213
2214         if (cmd == FUSE_DEV_IOC_CLONE) {
2215                 int oldfd;
2216
2217                 err = -EFAULT;
2218                 if (!get_user(oldfd, (__u32 __user *) arg)) {
2219                         struct file *old = fget(oldfd);
2220
2221                         err = -EINVAL;
2222                         if (old) {
2223                                 struct fuse_dev *fud = NULL;
2224
2225                                 /*
2226                                  * Check against file->f_op because CUSE
2227                                  * uses the same ioctl handler.
2228                                  */
2229                                 if (old->f_op == file->f_op &&
2230                                     old->f_cred->user_ns == file->f_cred->user_ns)
2231                                         fud = fuse_get_dev(old);
2232
2233                                 if (fud) {
2234                                         mutex_lock(&fuse_mutex);
2235                                         err = fuse_device_clone(fud->fc, file);
2236                                         mutex_unlock(&fuse_mutex);
2237                                 }
2238                                 fput(old);
2239                         }
2240                 }
2241         }
2242         return err;
2243 }
2244
2245 const struct file_operations fuse_dev_operations = {
2246         .owner          = THIS_MODULE,
2247         .open           = fuse_dev_open,
2248         .llseek         = no_llseek,
2249         .read_iter      = fuse_dev_read,
2250         .splice_read    = fuse_dev_splice_read,
2251         .write_iter     = fuse_dev_write,
2252         .splice_write   = fuse_dev_splice_write,
2253         .poll           = fuse_dev_poll,
2254         .release        = fuse_dev_release,
2255         .fasync         = fuse_dev_fasync,
2256         .unlocked_ioctl = fuse_dev_ioctl,
2257         .compat_ioctl   = fuse_dev_ioctl,
2258 };
2259 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2260
2261 static struct miscdevice fuse_miscdevice = {
2262         .minor = FUSE_MINOR,
2263         .name  = "fuse",
2264         .fops = &fuse_dev_operations,
2265 };
2266
2267 int __init fuse_dev_init(void)
2268 {
2269         int err = -ENOMEM;
2270         fuse_req_cachep = kmem_cache_create("fuse_request",
2271                                             sizeof(struct fuse_req),
2272                                             0, 0, NULL);
2273         if (!fuse_req_cachep)
2274                 goto out;
2275
2276         err = misc_register(&fuse_miscdevice);
2277         if (err)
2278                 goto out_cache_clean;
2279
2280         return 0;
2281
2282  out_cache_clean:
2283         kmem_cache_destroy(fuse_req_cachep);
2284  out:
2285         return err;
2286 }
2287
2288 void fuse_dev_cleanup(void)
2289 {
2290         misc_deregister(&fuse_miscdevice);
2291         kmem_cache_destroy(fuse_req_cachep);
2292 }