fs/fuse/dev.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/poll.h>
  14 #include <linux/uio.h>
  15 #include <linux/miscdevice.h>
  16 #include <linux/pagemap.h>
  17 #include <linux/file.h>
  18 #include <linux/slab.h>
  19 #include <linux/pipe_fs_i.h>
  20 #include <linux/swap.h>
  21 #include <linux/splice.h>
  22
  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
1368         if (!pipe->readers) {
1369                 send_sig(SIGPIPE, current, 0);
1370                 if (!ret)
1371                         ret = -EPIPE;
1372                 goto out_unlock;
1373         }
1374
1375         if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1376                 ret = -EIO;
1377                 goto out_unlock;
1378         }
1379
1380         while (page_nr < cs.nr_segs) {
1381                 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1382                 struct pipe_buffer *buf = pipe->bufs + newbuf;
1383
1384                 buf->page = bufs[page_nr].page;
1385                 buf->offset = bufs[page_nr].offset;
1386                 buf->len = bufs[page_nr].len;
1387                 /*
1388                  * Need to be careful about this.  Having buf->ops in module
1389                  * code can Oops if the buffer persists after module unload.
1390                  */
1391                 buf->ops = &nosteal_pipe_buf_ops;
1392
1393                 pipe->nrbufs++;
1394                 page_nr++;
1395                 ret += buf->len;
1396
1397                 if (pipe->files)
1398                         do_wakeup = 1;
1399         }
1400
1401 out_unlock:
1402
1403         if (do_wakeup) {
1404                 smp_mb();
1405                 if (waitqueue_active(&pipe->wait))
1406                         wake_up_interruptible(&pipe->wait);
1407                 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1408         }
1409
1410 out:
1411         for (; page_nr < cs.nr_segs; page_nr++)
1412                 put_page(bufs[page_nr].page);
1413
1414         kfree(bufs);
1415         return ret;
1416 }
1417
1418 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1419                             struct fuse_copy_state *cs)
1420 {
1421         struct fuse_notify_poll_wakeup_out outarg;
1422         int err = -EINVAL;
1423
1424         if (size != sizeof(outarg))
1425                 goto err;
1426
1427         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1428         if (err)
1429                 goto err;
1430
1431         fuse_copy_finish(cs);
1432         return fuse_notify_poll_wakeup(fc, &outarg);
1433
1434 err:
1435         fuse_copy_finish(cs);
1436         return err;
1437 }
1438
1439 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1440                                    struct fuse_copy_state *cs)
1441 {
1442         struct fuse_notify_inval_inode_out outarg;
1443         int err = -EINVAL;
1444
1445         if (size != sizeof(outarg))
1446                 goto err;
1447
1448         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1449         if (err)
1450                 goto err;
1451         fuse_copy_finish(cs);
1452
1453         down_read(&fc->killsb);
1454         err = -ENOENT;
1455         if (fc->sb) {
1456                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1457                                                outarg.off, outarg.len);
1458         }
1459         up_read(&fc->killsb);
1460         return err;
1461
1462 err:
1463         fuse_copy_finish(cs);
1464         return err;
1465 }
1466
1467 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1468                                    struct fuse_copy_state *cs)
1469 {
1470         struct fuse_notify_inval_entry_out outarg;
1471         int err = -ENOMEM;
1472         char *buf;
1473         struct qstr name;
1474
1475         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1476         if (!buf)
1477                 goto err;
1478
1479         err = -EINVAL;
1480         if (size < sizeof(outarg))
1481                 goto err;
1482
1483         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1484         if (err)
1485                 goto err;
1486
1487         err = -ENAMETOOLONG;
1488         if (outarg.namelen > FUSE_NAME_MAX)
1489                 goto err;
1490
1491         err = -EINVAL;
1492         if (size != sizeof(outarg) + outarg.namelen + 1)
1493                 goto err;
1494
1495         name.name = buf;
1496         name.len = outarg.namelen;
1497         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1498         if (err)
1499                 goto err;
1500         fuse_copy_finish(cs);
1501         buf[outarg.namelen] = 0;
1502
1503         down_read(&fc->killsb);
1504         err = -ENOENT;
1505         if (fc->sb)
1506                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1507         up_read(&fc->killsb);
1508         kfree(buf);
1509         return err;
1510
1511 err:
1512         kfree(buf);
1513         fuse_copy_finish(cs);
1514         return err;
1515 }
1516
1517 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1518                               struct fuse_copy_state *cs)
1519 {
1520         struct fuse_notify_delete_out outarg;
1521         int err = -ENOMEM;
1522         char *buf;
1523         struct qstr name;
1524
1525         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1526         if (!buf)
1527                 goto err;
1528
1529         err = -EINVAL;
1530         if (size < sizeof(outarg))
1531                 goto err;
1532
1533         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1534         if (err)
1535                 goto err;
1536
1537         err = -ENAMETOOLONG;
1538         if (outarg.namelen > FUSE_NAME_MAX)
1539                 goto err;
1540
1541         err = -EINVAL;
1542         if (size != sizeof(outarg) + outarg.namelen + 1)
1543                 goto err;
1544
1545         name.name = buf;
1546         name.len = outarg.namelen;
1547         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1548         if (err)
1549                 goto err;
1550         fuse_copy_finish(cs);
1551         buf[outarg.namelen] = 0;
1552
1553         down_read(&fc->killsb);
1554         err = -ENOENT;
1555         if (fc->sb)
1556                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1557                                                outarg.child, &name);
1558         up_read(&fc->killsb);
1559         kfree(buf);
1560         return err;
1561
1562 err:
1563         kfree(buf);
1564         fuse_copy_finish(cs);
1565         return err;
1566 }
1567
1568 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1569                              struct fuse_copy_state *cs)
1570 {
1571         struct fuse_notify_store_out outarg;
1572         struct inode *inode;
1573         struct address_space *mapping;
1574         u64 nodeid;
1575         int err;
1576         pgoff_t index;
1577         unsigned int offset;
1578         unsigned int num;
1579         loff_t file_size;
1580         loff_t end;
1581
1582         err = -EINVAL;
1583         if (size < sizeof(outarg))
1584                 goto out_finish;
1585
1586         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1587         if (err)
1588                 goto out_finish;
1589
1590         err = -EINVAL;
1591         if (size - sizeof(outarg) != outarg.size)
1592                 goto out_finish;
1593
1594         nodeid = outarg.nodeid;
1595
1596         down_read(&fc->killsb);
1597
1598         err = -ENOENT;
1599         if (!fc->sb)
1600                 goto out_up_killsb;
1601
1602         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1603         if (!inode)
1604                 goto out_up_killsb;
1605
1606         mapping = inode->i_mapping;
1607         index = outarg.offset >> PAGE_SHIFT;
1608         offset = outarg.offset & ~PAGE_MASK;
1609         file_size = i_size_read(inode);
1610         end = outarg.offset + outarg.size;
1611         if (end > file_size) {
1612                 file_size = end;
1613                 fuse_write_update_size(inode, file_size);
1614         }
1615
1616         num = outarg.size;
1617         while (num) {
1618                 struct page *page;
1619                 unsigned int this_num;
1620
1621                 err = -ENOMEM;
1622                 page = find_or_create_page(mapping, index,
1623                                            mapping_gfp_mask(mapping));
1624                 if (!page)
1625                         goto out_iput;
1626
1627                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1628                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1629                 if (!err && offset == 0 &&
1630                     (this_num == PAGE_SIZE || file_size == end))
1631                         SetPageUptodate(page);
1632                 unlock_page(page);
1633                 put_page(page);
1634
1635                 if (err)
1636                         goto out_iput;
1637
1638                 num -= this_num;
1639                 offset = 0;
1640                 index++;
1641         }
1642
1643         err = 0;
1644
1645 out_iput:
1646         iput(inode);
1647 out_up_killsb:
1648         up_read(&fc->killsb);
1649 out_finish:
1650         fuse_copy_finish(cs);
1651         return err;
1652 }
1653
1654 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1655 {
1656         release_pages(req->pages, req->num_pages, false);
1657 }
1658
1659 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1660                          struct fuse_notify_retrieve_out *outarg)
1661 {
1662         int err;
1663         struct address_space *mapping = inode->i_mapping;
1664         struct fuse_req *req;
1665         pgoff_t index;
1666         loff_t file_size;
1667         unsigned int num;
1668         unsigned int offset;
1669         size_t total_len = 0;
1670         int num_pages;
1671
1672         offset = outarg->offset & ~PAGE_MASK;
1673         file_size = i_size_read(inode);
1674
1675         num = outarg->size;
1676         if (outarg->offset > file_size)
1677                 num = 0;
1678         else if (outarg->offset + num > file_size)
1679                 num = file_size - outarg->offset;
1680
1681         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1682         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1683
1684         req = fuse_get_req(fc, num_pages);
1685         if (IS_ERR(req))
1686                 return PTR_ERR(req);
1687
1688         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1689         req->in.h.nodeid = outarg->nodeid;
1690         req->in.numargs = 2;
1691         req->in.argpages = 1;
1692         req->page_descs[0].offset = offset;
1693         req->end = fuse_retrieve_end;
1694
1695         index = outarg->offset >> PAGE_SHIFT;
1696
1697         while (num && req->num_pages < num_pages) {
1698                 struct page *page;
1699                 unsigned int this_num;
1700
1701                 page = find_get_page(mapping, index);
1702                 if (!page)
1703                         break;
1704
1705                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1706                 req->pages[req->num_pages] = page;
1707                 req->page_descs[req->num_pages].length = this_num;
1708                 req->num_pages++;
1709
1710                 offset = 0;
1711                 num -= this_num;
1712                 total_len += this_num;
1713                 index++;
1714         }
1715         req->misc.retrieve_in.offset = outarg->offset;
1716         req->misc.retrieve_in.size = total_len;
1717         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1718         req->in.args[0].value = &req->misc.retrieve_in;
1719         req->in.args[1].size = total_len;
1720
1721         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1722         if (err)
1723                 fuse_retrieve_end(fc, req);
1724
1725         return err;
1726 }
1727
1728 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1729                                 struct fuse_copy_state *cs)
1730 {
1731         struct fuse_notify_retrieve_out outarg;
1732         struct inode *inode;
1733         int err;
1734
1735         err = -EINVAL;
1736         if (size != sizeof(outarg))
1737                 goto copy_finish;
1738
1739         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1740         if (err)
1741                 goto copy_finish;
1742
1743         fuse_copy_finish(cs);
1744
1745         down_read(&fc->killsb);
1746         err = -ENOENT;
1747         if (fc->sb) {
1748                 u64 nodeid = outarg.nodeid;
1749
1750                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1751                 if (inode) {
1752                         err = fuse_retrieve(fc, inode, &outarg);
1753                         iput(inode);
1754                 }
1755         }
1756         up_read(&fc->killsb);
1757
1758         return err;
1759
1760 copy_finish:
1761         fuse_copy_finish(cs);
1762         return err;
1763 }
1764
1765 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1766                        unsigned int size, struct fuse_copy_state *cs)
1767 {
1768         /* Don't try to move pages (yet) */
1769         cs->move_pages = 0;
1770
1771         switch (code) {
1772         case FUSE_NOTIFY_POLL:
1773                 return fuse_notify_poll(fc, size, cs);
1774
1775         case FUSE_NOTIFY_INVAL_INODE:
1776                 return fuse_notify_inval_inode(fc, size, cs);
1777
1778         case FUSE_NOTIFY_INVAL_ENTRY:
1779                 return fuse_notify_inval_entry(fc, size, cs);
1780
1781         case FUSE_NOTIFY_STORE:
1782                 return fuse_notify_store(fc, size, cs);
1783
1784         case FUSE_NOTIFY_RETRIEVE:
1785                 return fuse_notify_retrieve(fc, size, cs);
1786
1787         case FUSE_NOTIFY_DELETE:
1788                 return fuse_notify_delete(fc, size, cs);
1789
1790         default:
1791                 fuse_copy_finish(cs);
1792                 return -EINVAL;
1793         }
1794 }
1795
1796 /* Look up request on processing list by unique ID */
1797 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1798 {
1799         struct fuse_req *req;
1800
1801         list_for_each_entry(req, &fpq->processing, list) {
1802                 if (req->in.h.unique == unique || req->intr_unique == unique)
1803                         return req;
1804         }
1805         return NULL;
1806 }
1807
1808 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1809                          unsigned nbytes)
1810 {
1811         unsigned reqsize = sizeof(struct fuse_out_header);
1812
1813         if (out->h.error)
1814                 return nbytes != reqsize ? -EINVAL : 0;
1815
1816         reqsize += len_args(out->numargs, out->args);
1817
1818         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1819                 return -EINVAL;
1820         else if (reqsize > nbytes) {
1821                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1822                 unsigned diffsize = reqsize - nbytes;
1823                 if (diffsize > lastarg->size)
1824                         return -EINVAL;
1825                 lastarg->size -= diffsize;
1826         }
1827         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1828                               out->page_zeroing);
1829 }
1830
1831 /*
1832  * Write a single reply to a request.  First the header is copied from
1833  * the write buffer.  The request is then searched on the processing
1834  * list by the unique ID found in the header.  If found, then remove
1835  * it from the list and copy the rest of the buffer to the request.
1836  * The request is finished by calling request_end()
1837  */
1838 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1839                                  struct fuse_copy_state *cs, size_t nbytes)
1840 {
1841         int err;
1842         struct fuse_conn *fc = fud->fc;
1843         struct fuse_pqueue *fpq = &fud->pq;
1844         struct fuse_req *req;
1845         struct fuse_out_header oh;
1846
1847         if (nbytes < sizeof(struct fuse_out_header))
1848                 return -EINVAL;
1849
1850         err = fuse_copy_one(cs, &oh, sizeof(oh));
1851         if (err)
1852                 goto err_finish;
1853
1854         err = -EINVAL;
1855         if (oh.len != nbytes)
1856                 goto err_finish;
1857
1858         /*
1859          * Zero oh.unique indicates unsolicited notification message
1860          * and error contains notification code.
1861          */
1862         if (!oh.unique) {
1863                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1864                 return err ? err : nbytes;
1865         }
1866
1867         err = -EINVAL;
1868         if (oh.error <= -1000 || oh.error > 0)
1869                 goto err_finish;
1870
1871         spin_lock(&fpq->lock);
1872         err = -ENOENT;
1873         if (!fpq->connected)
1874                 goto err_unlock_pq;
1875
1876         req = request_find(fpq, oh.unique);
1877         if (!req)
1878                 goto err_unlock_pq;
1879
1880         /* Is it an interrupt reply? */
1881         if (req->intr_unique == oh.unique) {
1882                 spin_unlock(&fpq->lock);
1883
1884                 err = -EINVAL;
1885                 if (nbytes != sizeof(struct fuse_out_header))
1886                         goto err_finish;
1887
1888                 if (oh.error == -ENOSYS)
1889                         fc->no_interrupt = 1;
1890                 else if (oh.error == -EAGAIN)
1891                         queue_interrupt(&fc->iq, req);
1892
1893                 fuse_copy_finish(cs);
1894                 return nbytes;
1895         }
1896
1897         clear_bit(FR_SENT, &req->flags);
1898         list_move(&req->list, &fpq->io);
1899         req->out.h = oh;
1900         set_bit(FR_LOCKED, &req->flags);
1901         spin_unlock(&fpq->lock);
1902         cs->req = req;
1903         if (!req->out.page_replace)
1904                 cs->move_pages = 0;
1905
1906         err = copy_out_args(cs, &req->out, nbytes);
1907         fuse_copy_finish(cs);
1908
1909         spin_lock(&fpq->lock);
1910         clear_bit(FR_LOCKED, &req->flags);
1911         if (!fpq->connected)
1912                 err = -ENOENT;
1913         else if (err)
1914                 req->out.h.error = -EIO;
1915         if (!test_bit(FR_PRIVATE, &req->flags))
1916                 list_del_init(&req->list);
1917         spin_unlock(&fpq->lock);
1918
1919         request_end(fc, req);
1920
1921         return err ? err : nbytes;
1922
1923  err_unlock_pq:
1924         spin_unlock(&fpq->lock);
1925  err_finish:
1926         fuse_copy_finish(cs);
1927         return err;
1928 }
1929
1930 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1931 {
1932         struct fuse_copy_state cs;
1933         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1934
1935         if (!fud)
1936                 return -EPERM;
1937
1938         if (!iter_is_iovec(from))
1939                 return -EINVAL;
1940
1941         fuse_copy_init(&cs, 0, from);
1942
1943         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1944 }
1945
1946 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1947                                      struct file *out, loff_t *ppos,
1948                                      size_t len, unsigned int flags)
1949 {
1950         unsigned nbuf;
1951         unsigned idx;
1952         struct pipe_buffer *bufs;
1953         struct fuse_copy_state cs;
1954         struct fuse_dev *fud;
1955         size_t rem;
1956         ssize_t ret;
1957
1958         fud = fuse_get_dev(out);
1959         if (!fud)
1960                 return -EPERM;
1961
1962         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1963         if (!bufs)
1964                 return -ENOMEM;
1965
1966         pipe_lock(pipe);
1967         nbuf = 0;
1968         rem = 0;
1969         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1970                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1971
1972         ret = -EINVAL;
1973         if (rem < len) {
1974                 pipe_unlock(pipe);
1975                 goto out;
1976         }
1977
1978         rem = len;
1979         while (rem) {
1980                 struct pipe_buffer *ibuf;
1981                 struct pipe_buffer *obuf;
1982
1983                 BUG_ON(nbuf >= pipe->buffers);
1984                 BUG_ON(!pipe->nrbufs);
1985                 ibuf = &pipe->bufs[pipe->curbuf];
1986                 obuf = &bufs[nbuf];
1987
1988                 if (rem >= ibuf->len) {
1989                         *obuf = *ibuf;
1990                         ibuf->ops = NULL;
1991                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1992                         pipe->nrbufs--;
1993                 } else {
1994                         ibuf->ops->get(pipe, ibuf);
1995                         *obuf = *ibuf;
1996                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1997                         obuf->len = rem;
1998                         ibuf->offset += obuf->len;
1999                         ibuf->len -= obuf->len;
2000                 }
2001                 nbuf++;
2002                 rem -= obuf->len;
2003         }
2004         pipe_unlock(pipe);
2005
2006         fuse_copy_init(&cs, 0, NULL);
2007         cs.pipebufs = bufs;
2008         cs.nr_segs = nbuf;
2009         cs.pipe = pipe;
2010
2011         if (flags & SPLICE_F_MOVE)
2012                 cs.move_pages = 1;
2013
2014         ret = fuse_dev_do_write(fud, &cs, len);
2015
2016         for (idx = 0; idx < nbuf; idx++) {
2017                 struct pipe_buffer *buf = &bufs[idx];
2018                 buf->ops->release(pipe, buf);
2019         }
2020 out:
2021         kfree(bufs);
2022         return ret;
2023 }
2024
2025 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2026 {
2027         unsigned mask = POLLOUT | POLLWRNORM;
2028         struct fuse_iqueue *fiq;
2029         struct fuse_dev *fud = fuse_get_dev(file);
2030
2031         if (!fud)
2032                 return POLLERR;
2033
2034         fiq = &fud->fc->iq;
2035         poll_wait(file, &fiq->waitq, wait);
2036
2037         spin_lock(&fiq->waitq.lock);
2038         if (!fiq->connected)
2039                 mask = POLLERR;
2040         else if (request_pending(fiq))
2041                 mask |= POLLIN | POLLRDNORM;
2042         spin_unlock(&fiq->waitq.lock);
2043
2044         return mask;
2045 }
2046
2047 /*
2048  * Abort all requests on the given list (pending or processing)
2049  *
2050  * This function releases and reacquires fc->lock
2051  */
2052 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2053 {
2054         while (!list_empty(head)) {
2055                 struct fuse_req *req;
2056                 req = list_entry(head->next, struct fuse_req, list);
2057                 req->out.h.error = -ECONNABORTED;
2058                 clear_bit(FR_PENDING, &req->flags);
2059                 clear_bit(FR_SENT, &req->flags);
2060                 list_del_init(&req->list);
2061                 request_end(fc, req);
2062         }
2063 }
2064
2065 static void end_polls(struct fuse_conn *fc)
2066 {
2067         struct rb_node *p;
2068
2069         p = rb_first(&fc->polled_files);
2070
2071         while (p) {
2072                 struct fuse_file *ff;
2073                 ff = rb_entry(p, struct fuse_file, polled_node);
2074                 wake_up_interruptible_all(&ff->poll_wait);
2075
2076                 p = rb_next(p);
2077         }
2078 }
2079
2080 /*
2081  * Abort all requests.
2082  *
2083  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2084  * filesystem.
2085  *
2086  * The same effect is usually achievable through killing the filesystem daemon
2087  * and all users of the filesystem.  The exception is the combination of an
2088  * asynchronous request and the tricky deadlock (see
2089  * Documentation/filesystems/fuse.txt).
2090  *
2091  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2092  * requests, they should be finished off immediately.  Locked requests will be
2093  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2094  * requests.  It is possible that some request will finish before we can.  This
2095  * is OK, the request will in that case be removed from the list before we touch
2096  * it.
2097  */
2098 void fuse_abort_conn(struct fuse_conn *fc)
2099 {
2100         struct fuse_iqueue *fiq = &fc->iq;
2101
2102         spin_lock(&fc->lock);
2103         if (fc->connected) {
2104                 struct fuse_dev *fud;
2105                 struct fuse_req *req, *next;
2106                 LIST_HEAD(to_end1);
2107                 LIST_HEAD(to_end2);
2108
2109                 fc->connected = 0;
2110                 fc->blocked = 0;
2111                 fuse_set_initialized(fc);
2112                 list_for_each_entry(fud, &fc->devices, entry) {
2113                         struct fuse_pqueue *fpq = &fud->pq;
2114
2115                         spin_lock(&fpq->lock);
2116                         fpq->connected = 0;
2117                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2118                                 req->out.h.error = -ECONNABORTED;
2119                                 spin_lock(&req->waitq.lock);
2120                                 set_bit(FR_ABORTED, &req->flags);
2121                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2122                                         set_bit(FR_PRIVATE, &req->flags);
2123                                         list_move(&req->list, &to_end1);
2124                                 }
2125                                 spin_unlock(&req->waitq.lock);
2126                         }
2127                         list_splice_init(&fpq->processing, &to_end2);
2128                         spin_unlock(&fpq->lock);
2129                 }
2130                 fc->max_background = UINT_MAX;
2131                 flush_bg_queue(fc);
2132
2133                 spin_lock(&fiq->waitq.lock);
2134                 fiq->connected = 0;
2135                 list_splice_init(&fiq->pending, &to_end2);
2136                 while (forget_pending(fiq))
2137                         kfree(dequeue_forget(fiq, 1, NULL));
2138                 wake_up_all_locked(&fiq->waitq);
2139                 spin_unlock(&fiq->waitq.lock);
2140                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2141                 end_polls(fc);
2142                 wake_up_all(&fc->blocked_waitq);
2143                 spin_unlock(&fc->lock);
2144
2145                 while (!list_empty(&to_end1)) {
2146                         req = list_first_entry(&to_end1, struct fuse_req, list);
2147                         __fuse_get_request(req);
2148                         list_del_init(&req->list);
2149                         request_end(fc, req);
2150                 }
2151                 end_requests(fc, &to_end2);
2152         } else {
2153                 spin_unlock(&fc->lock);
2154         }
2155 }
2156 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2157
2158 int fuse_dev_release(struct inode *inode, struct file *file)
2159 {
2160         struct fuse_dev *fud = fuse_get_dev(file);
2161
2162         if (fud) {
2163                 struct fuse_conn *fc = fud->fc;
2164                 struct fuse_pqueue *fpq = &fud->pq;
2165
2166                 WARN_ON(!list_empty(&fpq->io));
2167                 end_requests(fc, &fpq->processing);
2168                 /* Are we the last open device? */
2169                 if (atomic_dec_and_test(&fc->dev_count)) {
2170                         WARN_ON(fc->iq.fasync != NULL);
2171                         fuse_abort_conn(fc);
2172                 }
2173                 fuse_dev_free(fud);
2174         }
2175         return 0;
2176 }
2177 EXPORT_SYMBOL_GPL(fuse_dev_release);
2178
2179 static int fuse_dev_fasync(int fd, struct file *file, int on)
2180 {
2181         struct fuse_dev *fud = fuse_get_dev(file);
2182
2183         if (!fud)
2184                 return -EPERM;
2185
2186         /* No locking - fasync_helper does its own locking */
2187         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2188 }
2189
2190 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2191 {
2192         struct fuse_dev *fud;
2193
2194         if (new->private_data)
2195                 return -EINVAL;
2196
2197         fud = fuse_dev_alloc(fc);
2198         if (!fud)
2199                 return -ENOMEM;
2200
2201         new->private_data = fud;
2202         atomic_inc(&fc->dev_count);
2203
2204         return 0;
2205 }
2206
2207 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2208                            unsigned long arg)
2209 {
2210         int err = -ENOTTY;
2211
2212         if (cmd == FUSE_DEV_IOC_CLONE) {
2213                 int oldfd;
2214
2215                 err = -EFAULT;
2216                 if (!get_user(oldfd, (__u32 __user *) arg)) {
2217                         struct file *old = fget(oldfd);
2218
2219                         err = -EINVAL;
2220                         if (old) {
2221                                 struct fuse_dev *fud = NULL;
2222
2223                                 /*
2224                                  * Check against file->f_op because CUSE
2225                                  * uses the same ioctl handler.
2226                                  */
2227                                 if (old->f_op == file->f_op &&
2228                                     old->f_cred->user_ns == file->f_cred->user_ns)
2229                                         fud = fuse_get_dev(old);
2230
2231                                 if (fud) {
2232                                         mutex_lock(&fuse_mutex);
2233                                         err = fuse_device_clone(fud->fc, file);
2234                                         mutex_unlock(&fuse_mutex);
2235                                 }
2236                                 fput(old);
2237                         }
2238                 }
2239         }
2240         return err;
2241 }
2242
2243 const struct file_operations fuse_dev_operations = {
2244         .owner          = THIS_MODULE,
2245         .open           = fuse_dev_open,
2246         .llseek         = no_llseek,
2247         .read_iter      = fuse_dev_read,
2248         .splice_read    = fuse_dev_splice_read,
2249         .write_iter     = fuse_dev_write,
2250         .splice_write   = fuse_dev_splice_write,
2251         .poll           = fuse_dev_poll,
2252         .release        = fuse_dev_release,
2253         .fasync         = fuse_dev_fasync,
2254         .unlocked_ioctl = fuse_dev_ioctl,
2255         .compat_ioctl   = fuse_dev_ioctl,
2256 };
2257 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2258
2259 static struct miscdevice fuse_miscdevice = {
2260         .minor = FUSE_MINOR,
2261         .name  = "fuse",
2262         .fops = &fuse_dev_operations,
2263 };
2264
2265 int __init fuse_dev_init(void)
2266 {
2267         int err = -ENOMEM;
2268         fuse_req_cachep = kmem_cache_create("fuse_request",
2269                                             sizeof(struct fuse_req),
2270                                             0, 0, NULL);
2271         if (!fuse_req_cachep)
2272                 goto out;
2273
2274         err = misc_register(&fuse_miscdevice);
2275         if (err)
2276                 goto out_cache_clean;
2277
2278         return 0;
2279
2280  out_cache_clean:
2281         kmem_cache_destroy(fuse_req_cachep);
2282  out:
2283         return err;
2284 }
2285
2286 void fuse_dev_cleanup(void)
2287 {
2288         misc_deregister(&fuse_miscdevice);
2289         kmem_cache_destroy(fuse_req_cachep);
2290 }