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                 iov_iter_advance(cs->iter, err);
 771         }
 772
 773         return lock_request(cs->req);
 774 }
 775
 776 /* Do as much copy to/from userspace buffer as we can */
 777 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 778 {
 779         unsigned ncpy = min(*size, cs->len);
 780         if (val) {
 781                 void *pgaddr = kmap_atomic(cs->pg);
 782                 void *buf = pgaddr + cs->offset;
 783
 784                 if (cs->write)
 785                         memcpy(buf, *val, ncpy);
 786                 else
 787                         memcpy(*val, buf, ncpy);
 788
 789                 kunmap_atomic(pgaddr);
 790                 *val += ncpy;
 791         }
 792         *size -= ncpy;
 793         cs->len -= ncpy;
 794         cs->offset += ncpy;
 795         return ncpy;
 796 }
 797
 798 static int fuse_check_page(struct page *page)
 799 {
 800         if (page_mapcount(page) ||
 801             page->mapping != NULL ||
 802             page_count(page) != 1 ||
 803             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 804              ~(1 << PG_locked |
 805                1 << PG_referenced |
 806                1 << PG_uptodate |
 807                1 << PG_lru |
 808                1 << PG_active |
 809                1 << PG_reclaim))) {
 810                 printk(KERN_WARNING "fuse: trying to steal weird page\n");
 811                 printk(KERN_WARNING "  page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
 812                 return 1;
 813         }
 814         return 0;
 815 }
 816
 817 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 818 {
 819         int err;
 820         struct page *oldpage = *pagep;
 821         struct page *newpage;
 822         struct pipe_buffer *buf = cs->pipebufs;
 823
 824         err = unlock_request(cs->req);
 825         if (err)
 826                 return err;
 827
 828         fuse_copy_finish(cs);
 829
 830         err = buf->ops->confirm(cs->pipe, buf);
 831         if (err)
 832                 return err;
 833
 834         BUG_ON(!cs->nr_segs);
 835         cs->currbuf = buf;
 836         cs->len = buf->len;
 837         cs->pipebufs++;
 838         cs->nr_segs--;
 839
 840         if (cs->len != PAGE_SIZE)
 841                 goto out_fallback;
 842
 843         if (buf->ops->steal(cs->pipe, buf) != 0)
 844                 goto out_fallback;
 845
 846         newpage = buf->page;
 847
 848         if (!PageUptodate(newpage))
 849                 SetPageUptodate(newpage);
 850
 851         ClearPageMappedToDisk(newpage);
 852
 853         if (fuse_check_page(newpage) != 0)
 854                 goto out_fallback_unlock;
 855
 856         /*
 857          * This is a new and locked page, it shouldn't be mapped or
 858          * have any special flags on it
 859          */
 860         if (WARN_ON(page_mapped(oldpage)))
 861                 goto out_fallback_unlock;
 862         if (WARN_ON(page_has_private(oldpage)))
 863                 goto out_fallback_unlock;
 864         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 865                 goto out_fallback_unlock;
 866         if (WARN_ON(PageMlocked(oldpage)))
 867                 goto out_fallback_unlock;
 868
 869         err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 870         if (err) {
 871                 unlock_page(newpage);
 872                 return err;
 873         }
 874
 875         get_page(newpage);
 876
 877         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 878                 lru_cache_add_file(newpage);
 879
 880         err = 0;
 881         spin_lock(&cs->req->waitq.lock);
 882         if (test_bit(FR_ABORTED, &cs->req->flags))
 883                 err = -ENOENT;
 884         else
 885                 *pagep = newpage;
 886         spin_unlock(&cs->req->waitq.lock);
 887
 888         if (err) {
 889                 unlock_page(newpage);
 890                 put_page(newpage);
 891                 return err;
 892         }
 893
 894         unlock_page(oldpage);
 895         put_page(oldpage);
 896         cs->len = 0;
 897
 898         return 0;
 899
 900 out_fallback_unlock:
 901         unlock_page(newpage);
 902 out_fallback:
 903         cs->pg = buf->page;
 904         cs->offset = buf->offset;
 905
 906         err = lock_request(cs->req);
 907         if (err)
 908                 return err;
 909
 910         return 1;
 911 }
 912
 913 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 914                          unsigned offset, unsigned count)
 915 {
 916         struct pipe_buffer *buf;
 917         int err;
 918
 919         if (cs->nr_segs == cs->pipe->buffers)
 920                 return -EIO;
 921
 922         err = unlock_request(cs->req);
 923         if (err)
 924                 return err;
 925
 926         fuse_copy_finish(cs);
 927
 928         buf = cs->pipebufs;
 929         get_page(page);
 930         buf->page = page;
 931         buf->offset = offset;
 932         buf->len = count;
 933
 934         cs->pipebufs++;
 935         cs->nr_segs++;
 936         cs->len = 0;
 937
 938         return 0;
 939 }
 940
 941 /*
 942  * Copy a page in the request to/from the userspace buffer.  Must be
 943  * done atomically
 944  */
 945 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 946                           unsigned offset, unsigned count, int zeroing)
 947 {
 948         int err;
 949         struct page *page = *pagep;
 950
 951         if (page && zeroing && count < PAGE_SIZE)
 952                 clear_highpage(page);
 953
 954         while (count) {
 955                 if (cs->write && cs->pipebufs && page) {
 956                         return fuse_ref_page(cs, page, offset, count);
 957                 } else if (!cs->len) {
 958                         if (cs->move_pages && page &&
 959                             offset == 0 && count == PAGE_SIZE) {
 960                                 err = fuse_try_move_page(cs, pagep);
 961                                 if (err <= 0)
 962                                         return err;
 963                         } else {
 964                                 err = fuse_copy_fill(cs);
 965                                 if (err)
 966                                         return err;
 967                         }
 968                 }
 969                 if (page) {
 970                         void *mapaddr = kmap_atomic(page);
 971                         void *buf = mapaddr + offset;
 972                         offset += fuse_copy_do(cs, &buf, &count);
 973                         kunmap_atomic(mapaddr);
 974                 } else
 975                         offset += fuse_copy_do(cs, NULL, &count);
 976         }
 977         if (page && !cs->write)
 978                 flush_dcache_page(page);
 979         return 0;
 980 }
 981
 982 /* Copy pages in the request to/from userspace buffer */
 983 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 984                            int zeroing)
 985 {
 986         unsigned i;
 987         struct fuse_req *req = cs->req;
 988
 989         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
 990                 int err;
 991                 unsigned offset = req->page_descs[i].offset;
 992                 unsigned count = min(nbytes, req->page_descs[i].length);
 993
 994                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
 995                                      zeroing);
 996                 if (err)
 997                         return err;
 998
 999                 nbytes -= count;
1000         }
1001         return 0;
1002 }
1003
1004 /* Copy a single argument in the request to/from userspace buffer */
1005 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1006 {
1007         while (size) {
1008                 if (!cs->len) {
1009                         int err = fuse_copy_fill(cs);
1010                         if (err)
1011                                 return err;
1012                 }
1013                 fuse_copy_do(cs, &val, &size);
1014         }
1015         return 0;
1016 }
1017
1018 /* Copy request arguments to/from userspace buffer */
1019 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1020                           unsigned argpages, struct fuse_arg *args,
1021                           int zeroing)
1022 {
1023         int err = 0;
1024         unsigned i;
1025
1026         for (i = 0; !err && i < numargs; i++)  {
1027                 struct fuse_arg *arg = &args[i];
1028                 if (i == numargs - 1 && argpages)
1029                         err = fuse_copy_pages(cs, arg->size, zeroing);
1030                 else
1031                         err = fuse_copy_one(cs, arg->value, arg->size);
1032         }
1033         return err;
1034 }
1035
1036 static int forget_pending(struct fuse_iqueue *fiq)
1037 {
1038         return fiq->forget_list_head.next != NULL;
1039 }
1040
1041 static int request_pending(struct fuse_iqueue *fiq)
1042 {
1043         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1044                 forget_pending(fiq);
1045 }
1046
1047 /*
1048  * Transfer an interrupt request to userspace
1049  *
1050  * Unlike other requests this is assembled on demand, without a need
1051  * to allocate a separate fuse_req structure.
1052  *
1053  * Called with fiq->waitq.lock held, releases it
1054  */
1055 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1056                                struct fuse_copy_state *cs,
1057                                size_t nbytes, struct fuse_req *req)
1058 __releases(fiq->waitq.lock)
1059 {
1060         struct fuse_in_header ih;
1061         struct fuse_interrupt_in arg;
1062         unsigned reqsize = sizeof(ih) + sizeof(arg);
1063         int err;
1064
1065         list_del_init(&req->intr_entry);
1066         req->intr_unique = fuse_get_unique(fiq);
1067         memset(&ih, 0, sizeof(ih));
1068         memset(&arg, 0, sizeof(arg));
1069         ih.len = reqsize;
1070         ih.opcode = FUSE_INTERRUPT;
1071         ih.unique = req->intr_unique;
1072         arg.unique = req->in.h.unique;
1073
1074         spin_unlock(&fiq->waitq.lock);
1075         if (nbytes < reqsize)
1076                 return -EINVAL;
1077
1078         err = fuse_copy_one(cs, &ih, sizeof(ih));
1079         if (!err)
1080                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1081         fuse_copy_finish(cs);
1082
1083         return err ? err : reqsize;
1084 }
1085
1086 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1087                                                unsigned max,
1088                                                unsigned *countp)
1089 {
1090         struct fuse_forget_link *head = fiq->forget_list_head.next;
1091         struct fuse_forget_link **newhead = &head;
1092         unsigned count;
1093
1094         for (count = 0; *newhead != NULL && count < max; count++)
1095                 newhead = &(*newhead)->next;
1096
1097         fiq->forget_list_head.next = *newhead;
1098         *newhead = NULL;
1099         if (fiq->forget_list_head.next == NULL)
1100                 fiq->forget_list_tail = &fiq->forget_list_head;
1101
1102         if (countp != NULL)
1103                 *countp = count;
1104
1105         return head;
1106 }
1107
1108 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1109                                    struct fuse_copy_state *cs,
1110                                    size_t nbytes)
1111 __releases(fiq->waitq.lock)
1112 {
1113         int err;
1114         struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1115         struct fuse_forget_in arg = {
1116                 .nlookup = forget->forget_one.nlookup,
1117         };
1118         struct fuse_in_header ih = {
1119                 .opcode = FUSE_FORGET,
1120                 .nodeid = forget->forget_one.nodeid,
1121                 .unique = fuse_get_unique(fiq),
1122                 .len = sizeof(ih) + sizeof(arg),
1123         };
1124
1125         spin_unlock(&fiq->waitq.lock);
1126         kfree(forget);
1127         if (nbytes < ih.len)
1128                 return -EINVAL;
1129
1130         err = fuse_copy_one(cs, &ih, sizeof(ih));
1131         if (!err)
1132                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1133         fuse_copy_finish(cs);
1134
1135         if (err)
1136                 return err;
1137
1138         return ih.len;
1139 }
1140
1141 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1142                                    struct fuse_copy_state *cs, size_t nbytes)
1143 __releases(fiq->waitq.lock)
1144 {
1145         int err;
1146         unsigned max_forgets;
1147         unsigned count;
1148         struct fuse_forget_link *head;
1149         struct fuse_batch_forget_in arg = { .count = 0 };
1150         struct fuse_in_header ih = {
1151                 .opcode = FUSE_BATCH_FORGET,
1152                 .unique = fuse_get_unique(fiq),
1153                 .len = sizeof(ih) + sizeof(arg),
1154         };
1155
1156         if (nbytes < ih.len) {
1157                 spin_unlock(&fiq->waitq.lock);
1158                 return -EINVAL;
1159         }
1160
1161         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1162         head = dequeue_forget(fiq, max_forgets, &count);
1163         spin_unlock(&fiq->waitq.lock);
1164
1165         arg.count = count;
1166         ih.len += count * sizeof(struct fuse_forget_one);
1167         err = fuse_copy_one(cs, &ih, sizeof(ih));
1168         if (!err)
1169                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1170
1171         while (head) {
1172                 struct fuse_forget_link *forget = head;
1173
1174                 if (!err) {
1175                         err = fuse_copy_one(cs, &forget->forget_one,
1176                                             sizeof(forget->forget_one));
1177                 }
1178                 head = forget->next;
1179                 kfree(forget);
1180         }
1181
1182         fuse_copy_finish(cs);
1183
1184         if (err)
1185                 return err;
1186
1187         return ih.len;
1188 }
1189
1190 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1191                             struct fuse_copy_state *cs,
1192                             size_t nbytes)
1193 __releases(fiq->waitq.lock)
1194 {
1195         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1196                 return fuse_read_single_forget(fiq, cs, nbytes);
1197         else
1198                 return fuse_read_batch_forget(fiq, cs, nbytes);
1199 }
1200
1201 /*
1202  * Read a single request into the userspace filesystem's buffer.  This
1203  * function waits until a request is available, then removes it from
1204  * the pending list and copies request data to userspace buffer.  If
1205  * no reply is needed (FORGET) or request has been aborted or there
1206  * was an error during the copying then it's finished by calling
1207  * request_end().  Otherwise add it to the processing list, and set
1208  * the 'sent' flag.
1209  */
1210 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1211                                 struct fuse_copy_state *cs, size_t nbytes)
1212 {
1213         ssize_t err;
1214         struct fuse_conn *fc = fud->fc;
1215         struct fuse_iqueue *fiq = &fc->iq;
1216         struct fuse_pqueue *fpq = &fud->pq;
1217         struct fuse_req *req;
1218         struct fuse_in *in;
1219         unsigned reqsize;
1220
1221  restart:
1222         spin_lock(&fiq->waitq.lock);
1223         err = -EAGAIN;
1224         if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1225             !request_pending(fiq))
1226                 goto err_unlock;
1227
1228         err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1229                                 !fiq->connected || request_pending(fiq));
1230         if (err)
1231                 goto err_unlock;
1232
1233         err = -ENODEV;
1234         if (!fiq->connected)
1235                 goto err_unlock;
1236
1237         if (!list_empty(&fiq->interrupts)) {
1238                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1239                                  intr_entry);
1240                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1241         }
1242
1243         if (forget_pending(fiq)) {
1244                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1245                         return fuse_read_forget(fc, fiq, cs, nbytes);
1246
1247                 if (fiq->forget_batch <= -8)
1248                         fiq->forget_batch = 16;
1249         }
1250
1251         req = list_entry(fiq->pending.next, struct fuse_req, list);
1252         clear_bit(FR_PENDING, &req->flags);
1253         list_del_init(&req->list);
1254         spin_unlock(&fiq->waitq.lock);
1255
1256         in = &req->in;
1257         reqsize = in->h.len;
1258         /* If request is too large, reply with an error and restart the read */
1259         if (nbytes < reqsize) {
1260                 req->out.h.error = -EIO;
1261                 /* SETXATTR is special, since it may contain too large data */
1262                 if (in->h.opcode == FUSE_SETXATTR)
1263                         req->out.h.error = -E2BIG;
1264                 request_end(fc, req);
1265                 goto restart;
1266         }
1267         spin_lock(&fpq->lock);
1268         list_add(&req->list, &fpq->io);
1269         spin_unlock(&fpq->lock);
1270         cs->req = req;
1271         err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1272         if (!err)
1273                 err = fuse_copy_args(cs, in->numargs, in->argpages,
1274                                      (struct fuse_arg *) in->args, 0);
1275         fuse_copy_finish(cs);
1276         spin_lock(&fpq->lock);
1277         clear_bit(FR_LOCKED, &req->flags);
1278         if (!fpq->connected) {
1279                 err = -ENODEV;
1280                 goto out_end;
1281         }
1282         if (err) {
1283                 req->out.h.error = -EIO;
1284                 goto out_end;
1285         }
1286         if (!test_bit(FR_ISREPLY, &req->flags)) {
1287                 err = reqsize;
1288                 goto out_end;
1289         }
1290         list_move_tail(&req->list, &fpq->processing);
1291         spin_unlock(&fpq->lock);
1292         set_bit(FR_SENT, &req->flags);
1293         /* matches barrier in request_wait_answer() */
1294         smp_mb__after_atomic();
1295         if (test_bit(FR_INTERRUPTED, &req->flags))
1296                 queue_interrupt(fiq, req);
1297
1298         return reqsize;
1299
1300 out_end:
1301         if (!test_bit(FR_PRIVATE, &req->flags))
1302                 list_del_init(&req->list);
1303         spin_unlock(&fpq->lock);
1304         request_end(fc, req);
1305         return err;
1306
1307  err_unlock:
1308         spin_unlock(&fiq->waitq.lock);
1309         return err;
1310 }
1311
1312 static int fuse_dev_open(struct inode *inode, struct file *file)
1313 {
1314         /*
1315          * The fuse device's file's private_data is used to hold
1316          * the fuse_conn(ection) when it is mounted, and is used to
1317          * keep track of whether the file has been mounted already.
1318          */
1319         file->private_data = NULL;
1320         return 0;
1321 }
1322
1323 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1324 {
1325         struct fuse_copy_state cs;
1326         struct file *file = iocb->ki_filp;
1327         struct fuse_dev *fud = fuse_get_dev(file);
1328
1329         if (!fud)
1330                 return -EPERM;
1331
1332         if (!iter_is_iovec(to))
1333                 return -EINVAL;
1334
1335         fuse_copy_init(&cs, 1, to);
1336
1337         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1338 }
1339
1340 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1341                                     struct pipe_inode_info *pipe,
1342                                     size_t len, unsigned int flags)
1343 {
1344         int ret;
1345         int page_nr = 0;
1346         int do_wakeup = 0;
1347         struct pipe_buffer *bufs;
1348         struct fuse_copy_state cs;
1349         struct fuse_dev *fud = fuse_get_dev(in);
1350
1351         if (!fud)
1352                 return -EPERM;
1353
1354         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1355         if (!bufs)
1356                 return -ENOMEM;
1357
1358         fuse_copy_init(&cs, 1, NULL);
1359         cs.pipebufs = bufs;
1360         cs.pipe = pipe;
1361         ret = fuse_dev_do_read(fud, in, &cs, len);
1362         if (ret < 0)
1363                 goto out;
1364
1365         ret = 0;
1366         pipe_lock(pipe);
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         pipe_unlock(pipe);
1403
1404         if (do_wakeup) {
1405                 smp_mb();
1406                 if (waitqueue_active(&pipe->wait))
1407                         wake_up_interruptible(&pipe->wait);
1408                 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1409         }
1410
1411 out:
1412         for (; page_nr < cs.nr_segs; page_nr++)
1413                 put_page(bufs[page_nr].page);
1414
1415         kfree(bufs);
1416         return ret;
1417 }
1418
1419 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1420                             struct fuse_copy_state *cs)
1421 {
1422         struct fuse_notify_poll_wakeup_out outarg;
1423         int err = -EINVAL;
1424
1425         if (size != sizeof(outarg))
1426                 goto err;
1427
1428         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1429         if (err)
1430                 goto err;
1431
1432         fuse_copy_finish(cs);
1433         return fuse_notify_poll_wakeup(fc, &outarg);
1434
1435 err:
1436         fuse_copy_finish(cs);
1437         return err;
1438 }
1439
1440 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1441                                    struct fuse_copy_state *cs)
1442 {
1443         struct fuse_notify_inval_inode_out outarg;
1444         int err = -EINVAL;
1445
1446         if (size != sizeof(outarg))
1447                 goto err;
1448
1449         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1450         if (err)
1451                 goto err;
1452         fuse_copy_finish(cs);
1453
1454         down_read(&fc->killsb);
1455         err = -ENOENT;
1456         if (fc->sb) {
1457                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1458                                                outarg.off, outarg.len);
1459         }
1460         up_read(&fc->killsb);
1461         return err;
1462
1463 err:
1464         fuse_copy_finish(cs);
1465         return err;
1466 }
1467
1468 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1469                                    struct fuse_copy_state *cs)
1470 {
1471         struct fuse_notify_inval_entry_out outarg;
1472         int err = -ENOMEM;
1473         char *buf;
1474         struct qstr name;
1475
1476         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1477         if (!buf)
1478                 goto err;
1479
1480         err = -EINVAL;
1481         if (size < sizeof(outarg))
1482                 goto err;
1483
1484         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1485         if (err)
1486                 goto err;
1487
1488         err = -ENAMETOOLONG;
1489         if (outarg.namelen > FUSE_NAME_MAX)
1490                 goto err;
1491
1492         err = -EINVAL;
1493         if (size != sizeof(outarg) + outarg.namelen + 1)
1494                 goto err;
1495
1496         name.name = buf;
1497         name.len = outarg.namelen;
1498         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1499         if (err)
1500                 goto err;
1501         fuse_copy_finish(cs);
1502         buf[outarg.namelen] = 0;
1503
1504         down_read(&fc->killsb);
1505         err = -ENOENT;
1506         if (fc->sb)
1507                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1508         up_read(&fc->killsb);
1509         kfree(buf);
1510         return err;
1511
1512 err:
1513         kfree(buf);
1514         fuse_copy_finish(cs);
1515         return err;
1516 }
1517
1518 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1519                               struct fuse_copy_state *cs)
1520 {
1521         struct fuse_notify_delete_out outarg;
1522         int err = -ENOMEM;
1523         char *buf;
1524         struct qstr name;
1525
1526         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1527         if (!buf)
1528                 goto err;
1529
1530         err = -EINVAL;
1531         if (size < sizeof(outarg))
1532                 goto err;
1533
1534         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1535         if (err)
1536                 goto err;
1537
1538         err = -ENAMETOOLONG;
1539         if (outarg.namelen > FUSE_NAME_MAX)
1540                 goto err;
1541
1542         err = -EINVAL;
1543         if (size != sizeof(outarg) + outarg.namelen + 1)
1544                 goto err;
1545
1546         name.name = buf;
1547         name.len = outarg.namelen;
1548         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1549         if (err)
1550                 goto err;
1551         fuse_copy_finish(cs);
1552         buf[outarg.namelen] = 0;
1553
1554         down_read(&fc->killsb);
1555         err = -ENOENT;
1556         if (fc->sb)
1557                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1558                                                outarg.child, &name);
1559         up_read(&fc->killsb);
1560         kfree(buf);
1561         return err;
1562
1563 err:
1564         kfree(buf);
1565         fuse_copy_finish(cs);
1566         return err;
1567 }
1568
1569 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1570                              struct fuse_copy_state *cs)
1571 {
1572         struct fuse_notify_store_out outarg;
1573         struct inode *inode;
1574         struct address_space *mapping;
1575         u64 nodeid;
1576         int err;
1577         pgoff_t index;
1578         unsigned int offset;
1579         unsigned int num;
1580         loff_t file_size;
1581         loff_t end;
1582
1583         err = -EINVAL;
1584         if (size < sizeof(outarg))
1585                 goto out_finish;
1586
1587         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1588         if (err)
1589                 goto out_finish;
1590
1591         err = -EINVAL;
1592         if (size - sizeof(outarg) != outarg.size)
1593                 goto out_finish;
1594
1595         nodeid = outarg.nodeid;
1596
1597         down_read(&fc->killsb);
1598
1599         err = -ENOENT;
1600         if (!fc->sb)
1601                 goto out_up_killsb;
1602
1603         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1604         if (!inode)
1605                 goto out_up_killsb;
1606
1607         mapping = inode->i_mapping;
1608         index = outarg.offset >> PAGE_SHIFT;
1609         offset = outarg.offset & ~PAGE_MASK;
1610         file_size = i_size_read(inode);
1611         end = outarg.offset + outarg.size;
1612         if (end > file_size) {
1613                 file_size = end;
1614                 fuse_write_update_size(inode, file_size);
1615         }
1616
1617         num = outarg.size;
1618         while (num) {
1619                 struct page *page;
1620                 unsigned int this_num;
1621
1622                 err = -ENOMEM;
1623                 page = find_or_create_page(mapping, index,
1624                                            mapping_gfp_mask(mapping));
1625                 if (!page)
1626                         goto out_iput;
1627
1628                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1629                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1630                 if (!err && offset == 0 &&
1631                     (this_num == PAGE_SIZE || file_size == end))
1632                         SetPageUptodate(page);
1633                 unlock_page(page);
1634                 put_page(page);
1635
1636                 if (err)
1637                         goto out_iput;
1638
1639                 num -= this_num;
1640                 offset = 0;
1641                 index++;
1642         }
1643
1644         err = 0;
1645
1646 out_iput:
1647         iput(inode);
1648 out_up_killsb:
1649         up_read(&fc->killsb);
1650 out_finish:
1651         fuse_copy_finish(cs);
1652         return err;
1653 }
1654
1655 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1656 {
1657         release_pages(req->pages, req->num_pages, false);
1658 }
1659
1660 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1661                          struct fuse_notify_retrieve_out *outarg)
1662 {
1663         int err;
1664         struct address_space *mapping = inode->i_mapping;
1665         struct fuse_req *req;
1666         pgoff_t index;
1667         loff_t file_size;
1668         unsigned int num;
1669         unsigned int offset;
1670         size_t total_len = 0;
1671         int num_pages;
1672
1673         offset = outarg->offset & ~PAGE_MASK;
1674         file_size = i_size_read(inode);
1675
1676         num = outarg->size;
1677         if (outarg->offset > file_size)
1678                 num = 0;
1679         else if (outarg->offset + num > file_size)
1680                 num = file_size - outarg->offset;
1681
1682         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1683         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1684
1685         req = fuse_get_req(fc, num_pages);
1686         if (IS_ERR(req))
1687                 return PTR_ERR(req);
1688
1689         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1690         req->in.h.nodeid = outarg->nodeid;
1691         req->in.numargs = 2;
1692         req->in.argpages = 1;
1693         req->page_descs[0].offset = offset;
1694         req->end = fuse_retrieve_end;
1695
1696         index = outarg->offset >> PAGE_SHIFT;
1697
1698         while (num && req->num_pages < num_pages) {
1699                 struct page *page;
1700                 unsigned int this_num;
1701
1702                 page = find_get_page(mapping, index);
1703                 if (!page)
1704                         break;
1705
1706                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1707                 req->pages[req->num_pages] = page;
1708                 req->page_descs[req->num_pages].length = this_num;
1709                 req->num_pages++;
1710
1711                 offset = 0;
1712                 num -= this_num;
1713                 total_len += this_num;
1714                 index++;
1715         }
1716         req->misc.retrieve_in.offset = outarg->offset;
1717         req->misc.retrieve_in.size = total_len;
1718         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1719         req->in.args[0].value = &req->misc.retrieve_in;
1720         req->in.args[1].size = total_len;
1721
1722         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1723         if (err)
1724                 fuse_retrieve_end(fc, req);
1725
1726         return err;
1727 }
1728
1729 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1730                                 struct fuse_copy_state *cs)
1731 {
1732         struct fuse_notify_retrieve_out outarg;
1733         struct inode *inode;
1734         int err;
1735
1736         err = -EINVAL;
1737         if (size != sizeof(outarg))
1738                 goto copy_finish;
1739
1740         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1741         if (err)
1742                 goto copy_finish;
1743
1744         fuse_copy_finish(cs);
1745
1746         down_read(&fc->killsb);
1747         err = -ENOENT;
1748         if (fc->sb) {
1749                 u64 nodeid = outarg.nodeid;
1750
1751                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1752                 if (inode) {
1753                         err = fuse_retrieve(fc, inode, &outarg);
1754                         iput(inode);
1755                 }
1756         }
1757         up_read(&fc->killsb);
1758
1759         return err;
1760
1761 copy_finish:
1762         fuse_copy_finish(cs);
1763         return err;
1764 }
1765
1766 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1767                        unsigned int size, struct fuse_copy_state *cs)
1768 {
1769         /* Don't try to move pages (yet) */
1770         cs->move_pages = 0;
1771
1772         switch (code) {
1773         case FUSE_NOTIFY_POLL:
1774                 return fuse_notify_poll(fc, size, cs);
1775
1776         case FUSE_NOTIFY_INVAL_INODE:
1777                 return fuse_notify_inval_inode(fc, size, cs);
1778
1779         case FUSE_NOTIFY_INVAL_ENTRY:
1780                 return fuse_notify_inval_entry(fc, size, cs);
1781
1782         case FUSE_NOTIFY_STORE:
1783                 return fuse_notify_store(fc, size, cs);
1784
1785         case FUSE_NOTIFY_RETRIEVE:
1786                 return fuse_notify_retrieve(fc, size, cs);
1787
1788         case FUSE_NOTIFY_DELETE:
1789                 return fuse_notify_delete(fc, size, cs);
1790
1791         default:
1792                 fuse_copy_finish(cs);
1793                 return -EINVAL;
1794         }
1795 }
1796
1797 /* Look up request on processing list by unique ID */
1798 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1799 {
1800         struct fuse_req *req;
1801
1802         list_for_each_entry(req, &fpq->processing, list) {
1803                 if (req->in.h.unique == unique || req->intr_unique == unique)
1804                         return req;
1805         }
1806         return NULL;
1807 }
1808
1809 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1810                          unsigned nbytes)
1811 {
1812         unsigned reqsize = sizeof(struct fuse_out_header);
1813
1814         if (out->h.error)
1815                 return nbytes != reqsize ? -EINVAL : 0;
1816
1817         reqsize += len_args(out->numargs, out->args);
1818
1819         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1820                 return -EINVAL;
1821         else if (reqsize > nbytes) {
1822                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1823                 unsigned diffsize = reqsize - nbytes;
1824                 if (diffsize > lastarg->size)
1825                         return -EINVAL;
1826                 lastarg->size -= diffsize;
1827         }
1828         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1829                               out->page_zeroing);
1830 }
1831
1832 /*
1833  * Write a single reply to a request.  First the header is copied from
1834  * the write buffer.  The request is then searched on the processing
1835  * list by the unique ID found in the header.  If found, then remove
1836  * it from the list and copy the rest of the buffer to the request.
1837  * The request is finished by calling request_end()
1838  */
1839 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1840                                  struct fuse_copy_state *cs, size_t nbytes)
1841 {
1842         int err;
1843         struct fuse_conn *fc = fud->fc;
1844         struct fuse_pqueue *fpq = &fud->pq;
1845         struct fuse_req *req;
1846         struct fuse_out_header oh;
1847
1848         if (nbytes < sizeof(struct fuse_out_header))
1849                 return -EINVAL;
1850
1851         err = fuse_copy_one(cs, &oh, sizeof(oh));
1852         if (err)
1853                 goto err_finish;
1854
1855         err = -EINVAL;
1856         if (oh.len != nbytes)
1857                 goto err_finish;
1858
1859         /*
1860          * Zero oh.unique indicates unsolicited notification message
1861          * and error contains notification code.
1862          */
1863         if (!oh.unique) {
1864                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1865                 return err ? err : nbytes;
1866         }
1867
1868         err = -EINVAL;
1869         if (oh.error <= -1000 || oh.error > 0)
1870                 goto err_finish;
1871
1872         spin_lock(&fpq->lock);
1873         err = -ENOENT;
1874         if (!fpq->connected)
1875                 goto err_unlock_pq;
1876
1877         req = request_find(fpq, oh.unique);
1878         if (!req)
1879                 goto err_unlock_pq;
1880
1881         /* Is it an interrupt reply? */
1882         if (req->intr_unique == oh.unique) {
1883                 spin_unlock(&fpq->lock);
1884
1885                 err = -EINVAL;
1886                 if (nbytes != sizeof(struct fuse_out_header))
1887                         goto err_finish;
1888
1889                 if (oh.error == -ENOSYS)
1890                         fc->no_interrupt = 1;
1891                 else if (oh.error == -EAGAIN)
1892                         queue_interrupt(&fc->iq, req);
1893
1894                 fuse_copy_finish(cs);
1895                 return nbytes;
1896         }
1897
1898         clear_bit(FR_SENT, &req->flags);
1899         list_move(&req->list, &fpq->io);
1900         req->out.h = oh;
1901         set_bit(FR_LOCKED, &req->flags);
1902         spin_unlock(&fpq->lock);
1903         cs->req = req;
1904         if (!req->out.page_replace)
1905                 cs->move_pages = 0;
1906
1907         err = copy_out_args(cs, &req->out, nbytes);
1908         fuse_copy_finish(cs);
1909
1910         spin_lock(&fpq->lock);
1911         clear_bit(FR_LOCKED, &req->flags);
1912         if (!fpq->connected)
1913                 err = -ENOENT;
1914         else if (err)
1915                 req->out.h.error = -EIO;
1916         if (!test_bit(FR_PRIVATE, &req->flags))
1917                 list_del_init(&req->list);
1918         spin_unlock(&fpq->lock);
1919
1920         request_end(fc, req);
1921
1922         return err ? err : nbytes;
1923
1924  err_unlock_pq:
1925         spin_unlock(&fpq->lock);
1926  err_finish:
1927         fuse_copy_finish(cs);
1928         return err;
1929 }
1930
1931 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1932 {
1933         struct fuse_copy_state cs;
1934         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1935
1936         if (!fud)
1937                 return -EPERM;
1938
1939         if (!iter_is_iovec(from))
1940                 return -EINVAL;
1941
1942         fuse_copy_init(&cs, 0, from);
1943
1944         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1945 }
1946
1947 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1948                                      struct file *out, loff_t *ppos,
1949                                      size_t len, unsigned int flags)
1950 {
1951         unsigned nbuf;
1952         unsigned idx;
1953         struct pipe_buffer *bufs;
1954         struct fuse_copy_state cs;
1955         struct fuse_dev *fud;
1956         size_t rem;
1957         ssize_t ret;
1958
1959         fud = fuse_get_dev(out);
1960         if (!fud)
1961                 return -EPERM;
1962
1963         bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1964         if (!bufs)
1965                 return -ENOMEM;
1966
1967         pipe_lock(pipe);
1968         nbuf = 0;
1969         rem = 0;
1970         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1971                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1972
1973         ret = -EINVAL;
1974         if (rem < len) {
1975                 pipe_unlock(pipe);
1976                 goto out;
1977         }
1978
1979         rem = len;
1980         while (rem) {
1981                 struct pipe_buffer *ibuf;
1982                 struct pipe_buffer *obuf;
1983
1984                 BUG_ON(nbuf >= pipe->buffers);
1985                 BUG_ON(!pipe->nrbufs);
1986                 ibuf = &pipe->bufs[pipe->curbuf];
1987                 obuf = &bufs[nbuf];
1988
1989                 if (rem >= ibuf->len) {
1990                         *obuf = *ibuf;
1991                         ibuf->ops = NULL;
1992                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1993                         pipe->nrbufs--;
1994                 } else {
1995                         ibuf->ops->get(pipe, ibuf);
1996                         *obuf = *ibuf;
1997                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1998                         obuf->len = rem;
1999                         ibuf->offset += obuf->len;
2000                         ibuf->len -= obuf->len;
2001                 }
2002                 nbuf++;
2003                 rem -= obuf->len;
2004         }
2005         pipe_unlock(pipe);
2006
2007         fuse_copy_init(&cs, 0, NULL);
2008         cs.pipebufs = bufs;
2009         cs.nr_segs = nbuf;
2010         cs.pipe = pipe;
2011
2012         if (flags & SPLICE_F_MOVE)
2013                 cs.move_pages = 1;
2014
2015         ret = fuse_dev_do_write(fud, &cs, len);
2016
2017         for (idx = 0; idx < nbuf; idx++) {
2018                 struct pipe_buffer *buf = &bufs[idx];
2019                 buf->ops->release(pipe, buf);
2020         }
2021 out:
2022         kfree(bufs);
2023         return ret;
2024 }
2025
2026 static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
2027 {
2028         unsigned mask = POLLOUT | POLLWRNORM;
2029         struct fuse_iqueue *fiq;
2030         struct fuse_dev *fud = fuse_get_dev(file);
2031
2032         if (!fud)
2033                 return POLLERR;
2034
2035         fiq = &fud->fc->iq;
2036         poll_wait(file, &fiq->waitq, wait);
2037
2038         spin_lock(&fiq->waitq.lock);
2039         if (!fiq->connected)
2040                 mask = POLLERR;
2041         else if (request_pending(fiq))
2042                 mask |= POLLIN | POLLRDNORM;
2043         spin_unlock(&fiq->waitq.lock);
2044
2045         return mask;
2046 }
2047
2048 /*
2049  * Abort all requests on the given list (pending or processing)
2050  *
2051  * This function releases and reacquires fc->lock
2052  */
2053 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2054 {
2055         while (!list_empty(head)) {
2056                 struct fuse_req *req;
2057                 req = list_entry(head->next, struct fuse_req, list);
2058                 req->out.h.error = -ECONNABORTED;
2059                 clear_bit(FR_PENDING, &req->flags);
2060                 clear_bit(FR_SENT, &req->flags);
2061                 list_del_init(&req->list);
2062                 request_end(fc, req);
2063         }
2064 }
2065
2066 static void end_polls(struct fuse_conn *fc)
2067 {
2068         struct rb_node *p;
2069
2070         p = rb_first(&fc->polled_files);
2071
2072         while (p) {
2073                 struct fuse_file *ff;
2074                 ff = rb_entry(p, struct fuse_file, polled_node);
2075                 wake_up_interruptible_all(&ff->poll_wait);
2076
2077                 p = rb_next(p);
2078         }
2079 }
2080
2081 /*
2082  * Abort all requests.
2083  *
2084  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2085  * filesystem.
2086  *
2087  * The same effect is usually achievable through killing the filesystem daemon
2088  * and all users of the filesystem.  The exception is the combination of an
2089  * asynchronous request and the tricky deadlock (see
2090  * Documentation/filesystems/fuse.txt).
2091  *
2092  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2093  * requests, they should be finished off immediately.  Locked requests will be
2094  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2095  * requests.  It is possible that some request will finish before we can.  This
2096  * is OK, the request will in that case be removed from the list before we touch
2097  * it.
2098  */
2099 void fuse_abort_conn(struct fuse_conn *fc)
2100 {
2101         struct fuse_iqueue *fiq = &fc->iq;
2102
2103         spin_lock(&fc->lock);
2104         if (fc->connected) {
2105                 struct fuse_dev *fud;
2106                 struct fuse_req *req, *next;
2107                 LIST_HEAD(to_end1);
2108                 LIST_HEAD(to_end2);
2109
2110                 fc->connected = 0;
2111                 fc->blocked = 0;
2112                 fuse_set_initialized(fc);
2113                 list_for_each_entry(fud, &fc->devices, entry) {
2114                         struct fuse_pqueue *fpq = &fud->pq;
2115
2116                         spin_lock(&fpq->lock);
2117                         fpq->connected = 0;
2118                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2119                                 req->out.h.error = -ECONNABORTED;
2120                                 spin_lock(&req->waitq.lock);
2121                                 set_bit(FR_ABORTED, &req->flags);
2122                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2123                                         set_bit(FR_PRIVATE, &req->flags);
2124                                         list_move(&req->list, &to_end1);
2125                                 }
2126                                 spin_unlock(&req->waitq.lock);
2127                         }
2128                         list_splice_init(&fpq->processing, &to_end2);
2129                         spin_unlock(&fpq->lock);
2130                 }
2131                 fc->max_background = UINT_MAX;
2132                 flush_bg_queue(fc);
2133
2134                 spin_lock(&fiq->waitq.lock);
2135                 fiq->connected = 0;
2136                 list_splice_init(&fiq->pending, &to_end2);
2137                 while (forget_pending(fiq))
2138                         kfree(dequeue_forget(fiq, 1, NULL));
2139                 wake_up_all_locked(&fiq->waitq);
2140                 spin_unlock(&fiq->waitq.lock);
2141                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2142                 end_polls(fc);
2143                 wake_up_all(&fc->blocked_waitq);
2144                 spin_unlock(&fc->lock);
2145
2146                 while (!list_empty(&to_end1)) {
2147                         req = list_first_entry(&to_end1, struct fuse_req, list);
2148                         __fuse_get_request(req);
2149                         list_del_init(&req->list);
2150                         request_end(fc, req);
2151                 }
2152                 end_requests(fc, &to_end2);
2153         } else {
2154                 spin_unlock(&fc->lock);
2155         }
2156 }
2157 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2158
2159 int fuse_dev_release(struct inode *inode, struct file *file)
2160 {
2161         struct fuse_dev *fud = fuse_get_dev(file);
2162
2163         if (fud) {
2164                 struct fuse_conn *fc = fud->fc;
2165                 struct fuse_pqueue *fpq = &fud->pq;
2166
2167                 WARN_ON(!list_empty(&fpq->io));
2168                 end_requests(fc, &fpq->processing);
2169                 /* Are we the last open device? */
2170                 if (atomic_dec_and_test(&fc->dev_count)) {
2171                         WARN_ON(fc->iq.fasync != NULL);
2172                         fuse_abort_conn(fc);
2173                 }
2174                 fuse_dev_free(fud);
2175         }
2176         return 0;
2177 }
2178 EXPORT_SYMBOL_GPL(fuse_dev_release);
2179
2180 static int fuse_dev_fasync(int fd, struct file *file, int on)
2181 {
2182         struct fuse_dev *fud = fuse_get_dev(file);
2183
2184         if (!fud)
2185                 return -EPERM;
2186
2187         /* No locking - fasync_helper does its own locking */
2188         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2189 }
2190
2191 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2192 {
2193         struct fuse_dev *fud;
2194
2195         if (new->private_data)
2196                 return -EINVAL;
2197
2198         fud = fuse_dev_alloc(fc);
2199         if (!fud)
2200                 return -ENOMEM;
2201
2202         new->private_data = fud;
2203         atomic_inc(&fc->dev_count);
2204
2205         return 0;
2206 }
2207
2208 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2209                            unsigned long arg)
2210 {
2211         int err = -ENOTTY;
2212
2213         if (cmd == FUSE_DEV_IOC_CLONE) {
2214                 int oldfd;
2215
2216                 err = -EFAULT;
2217                 if (!get_user(oldfd, (__u32 __user *) arg)) {
2218                         struct file *old = fget(oldfd);
2219
2220                         err = -EINVAL;
2221                         if (old) {
2222                                 struct fuse_dev *fud = NULL;
2223
2224                                 /*
2225                                  * Check against file->f_op because CUSE
2226                                  * uses the same ioctl handler.
2227                                  */
2228                                 if (old->f_op == file->f_op &&
2229                                     old->f_cred->user_ns == file->f_cred->user_ns)
2230                                         fud = fuse_get_dev(old);
2231
2232                                 if (fud) {
2233                                         mutex_lock(&fuse_mutex);
2234                                         err = fuse_device_clone(fud->fc, file);
2235                                         mutex_unlock(&fuse_mutex);
2236                                 }
2237                                 fput(old);
2238                         }
2239                 }
2240         }
2241         return err;
2242 }
2243
2244 const struct file_operations fuse_dev_operations = {
2245         .owner          = THIS_MODULE,
2246         .open           = fuse_dev_open,
2247         .llseek         = no_llseek,
2248         .read_iter      = fuse_dev_read,
2249         .splice_read    = fuse_dev_splice_read,
2250         .write_iter     = fuse_dev_write,
2251         .splice_write   = fuse_dev_splice_write,
2252         .poll           = fuse_dev_poll,
2253         .release        = fuse_dev_release,
2254         .fasync         = fuse_dev_fasync,
2255         .unlocked_ioctl = fuse_dev_ioctl,
2256         .compat_ioctl   = fuse_dev_ioctl,
2257 };
2258 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2259
2260 static struct miscdevice fuse_miscdevice = {
2261         .minor = FUSE_MINOR,
2262         .name  = "fuse",
2263         .fops = &fuse_dev_operations,
2264 };
2265
2266 int __init fuse_dev_init(void)
2267 {
2268         int err = -ENOMEM;
2269         fuse_req_cachep = kmem_cache_create("fuse_request",
2270                                             sizeof(struct fuse_req),
2271                                             0, 0, NULL);
2272         if (!fuse_req_cachep)
2273                 goto out;
2274
2275         err = misc_register(&fuse_miscdevice);
2276         if (err)
2277                 goto out_cache_clean;
2278
2279         return 0;
2280
2281  out_cache_clean:
2282         kmem_cache_destroy(fuse_req_cachep);
2283  out:
2284         return err;
2285 }
2286
2287 void fuse_dev_cleanup(void)
2288 {
2289         misc_deregister(&fuse_miscdevice);
2290         kmem_cache_destroy(fuse_req_cachep);
2291 }