fs/fuse/dev.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  Miklos Szeredi <[email protected]>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/poll.h>
  14 #include <linux/sched/signal.h>
  15 #include <linux/uio.h>
  16 #include <linux/miscdevice.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/file.h>
  19 #include <linux/slab.h>
  20 #include <linux/pipe_fs_i.h>
  21 #include <linux/swap.h>
  22 #include <linux/splice.h>
  23 #include <linux/sched.h>
  24
  25 MODULE_ALIAS_MISCDEV(FUSE_MINOR);
  26 MODULE_ALIAS("devname:fuse");
  27
  28 /* Ordinary requests have even IDs, while interrupts IDs are odd */
  29 #define FUSE_INT_REQ_BIT (1ULL << 0)
  30 #define FUSE_REQ_ID_STEP (1ULL << 1)
  31
  32 static struct kmem_cache *fuse_req_cachep;
  33
  34 static struct fuse_dev *fuse_get_dev(struct file *file)
  35 {
  36         /*
  37          * Lockless access is OK, because file->private data is set
  38          * once during mount and is valid until the file is released.
  39          */
  40         return READ_ONCE(file->private_data);
  41 }
  42
  43 static void fuse_request_init(struct fuse_mount *fm, struct fuse_req *req)
  44 {
  45         INIT_LIST_HEAD(&req->list);
  46         INIT_LIST_HEAD(&req->intr_entry);
  47         init_waitqueue_head(&req->waitq);
  48         refcount_set(&req->count, 1);
  49         __set_bit(FR_PENDING, &req->flags);
  50         req->fm = fm;
  51 }
  52
  53 static struct fuse_req *fuse_request_alloc(struct fuse_mount *fm, gfp_t flags)
  54 {
  55         struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
  56         if (req)
  57                 fuse_request_init(fm, req);
  58
  59         return req;
  60 }
  61
  62 static void fuse_request_free(struct fuse_req *req)
  63 {
  64         kmem_cache_free(fuse_req_cachep, req);
  65 }
  66
  67 static void __fuse_get_request(struct fuse_req *req)
  68 {
  69         refcount_inc(&req->count);
  70 }
  71
  72 /* Must be called with > 1 refcount */
  73 static void __fuse_put_request(struct fuse_req *req)
  74 {
  75         refcount_dec(&req->count);
  76 }
  77
  78 void fuse_set_initialized(struct fuse_conn *fc)
  79 {
  80         /* Make sure stores before this are seen on another CPU */
  81         smp_wmb();
  82         fc->initialized = 1;
  83 }
  84
  85 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
  86 {
  87         return !fc->initialized || (for_background && fc->blocked);
  88 }
  89
  90 static void fuse_drop_waiting(struct fuse_conn *fc)
  91 {
  92         /*
  93          * lockess check of fc->connected is okay, because atomic_dec_and_test()
  94          * provides a memory barrier mached with the one in fuse_wait_aborted()
  95          * to ensure no wake-up is missed.
  96          */
  97         if (atomic_dec_and_test(&fc->num_waiting) &&
  98             !READ_ONCE(fc->connected)) {
  99                 /* wake up aborters */
 100                 wake_up_all(&fc->blocked_waitq);
 101         }
 102 }
 103
 104 static void fuse_put_request(struct fuse_req *req);
 105
 106 static struct fuse_req *fuse_get_req(struct fuse_mount *fm, bool for_background)
 107 {
 108         struct fuse_conn *fc = fm->fc;
 109         struct fuse_req *req;
 110         int err;
 111         atomic_inc(&fc->num_waiting);
 112
 113         if (fuse_block_alloc(fc, for_background)) {
 114                 err = -EINTR;
 115                 if (wait_event_killable_exclusive(fc->blocked_waitq,
 116                                 !fuse_block_alloc(fc, for_background)))
 117                         goto out;
 118         }
 119         /* Matches smp_wmb() in fuse_set_initialized() */
 120         smp_rmb();
 121
 122         err = -ENOTCONN;
 123         if (!fc->connected)
 124                 goto out;
 125
 126         err = -ECONNREFUSED;
 127         if (fc->conn_error)
 128                 goto out;
 129
 130         req = fuse_request_alloc(fm, GFP_KERNEL);
 131         err = -ENOMEM;
 132         if (!req) {
 133                 if (for_background)
 134                         wake_up(&fc->blocked_waitq);
 135                 goto out;
 136         }
 137
 138         req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
 139         req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
 140         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 141
 142         __set_bit(FR_WAITING, &req->flags);
 143         if (for_background)
 144                 __set_bit(FR_BACKGROUND, &req->flags);
 145
 146         if (unlikely(req->in.h.uid == ((uid_t)-1) ||
 147                      req->in.h.gid == ((gid_t)-1))) {
 148                 fuse_put_request(req);
 149                 return ERR_PTR(-EOVERFLOW);
 150         }
 151         return req;
 152
 153  out:
 154         fuse_drop_waiting(fc);
 155         return ERR_PTR(err);
 156 }
 157
 158 static void fuse_put_request(struct fuse_req *req)
 159 {
 160         struct fuse_conn *fc = req->fm->fc;
 161
 162         if (refcount_dec_and_test(&req->count)) {
 163                 if (test_bit(FR_BACKGROUND, &req->flags)) {
 164                         /*
 165                          * We get here in the unlikely case that a background
 166                          * request was allocated but not sent
 167                          */
 168                         spin_lock(&fc->bg_lock);
 169                         if (!fc->blocked)
 170                                 wake_up(&fc->blocked_waitq);
 171                         spin_unlock(&fc->bg_lock);
 172                 }
 173
 174                 if (test_bit(FR_WAITING, &req->flags)) {
 175                         __clear_bit(FR_WAITING, &req->flags);
 176                         fuse_drop_waiting(fc);
 177                 }
 178
 179                 fuse_request_free(req);
 180         }
 181 }
 182
 183 unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
 184 {
 185         unsigned nbytes = 0;
 186         unsigned i;
 187
 188         for (i = 0; i < numargs; i++)
 189                 nbytes += args[i].size;
 190
 191         return nbytes;
 192 }
 193 EXPORT_SYMBOL_GPL(fuse_len_args);
 194
 195 u64 fuse_get_unique(struct fuse_iqueue *fiq)
 196 {
 197         fiq->reqctr += FUSE_REQ_ID_STEP;
 198         return fiq->reqctr;
 199 }
 200 EXPORT_SYMBOL_GPL(fuse_get_unique);
 201
 202 static unsigned int fuse_req_hash(u64 unique)
 203 {
 204         return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
 205 }
 206
 207 /**
 208  * A new request is available, wake fiq->waitq
 209  */
 210 static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq)
 211 __releases(fiq->lock)
 212 {
 213         wake_up(&fiq->waitq);
 214         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 215         spin_unlock(&fiq->lock);
 216 }
 217
 218 const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
 219         .wake_forget_and_unlock         = fuse_dev_wake_and_unlock,
 220         .wake_interrupt_and_unlock      = fuse_dev_wake_and_unlock,
 221         .wake_pending_and_unlock        = fuse_dev_wake_and_unlock,
 222 };
 223 EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
 224
 225 static void queue_request_and_unlock(struct fuse_iqueue *fiq,
 226                                      struct fuse_req *req)
 227 __releases(fiq->lock)
 228 {
 229         req->in.h.len = sizeof(struct fuse_in_header) +
 230                 fuse_len_args(req->args->in_numargs,
 231                               (struct fuse_arg *) req->args->in_args);
 232         list_add_tail(&req->list, &fiq->pending);
 233         fiq->ops->wake_pending_and_unlock(fiq);
 234 }
 235
 236 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 237                        u64 nodeid, u64 nlookup)
 238 {
 239         struct fuse_iqueue *fiq = &fc->iq;
 240
 241         forget->forget_one.nodeid = nodeid;
 242         forget->forget_one.nlookup = nlookup;
 243
 244         spin_lock(&fiq->lock);
 245         if (fiq->connected) {
 246                 fiq->forget_list_tail->next = forget;
 247                 fiq->forget_list_tail = forget;
 248                 fiq->ops->wake_forget_and_unlock(fiq);
 249         } else {
 250                 kfree(forget);
 251                 spin_unlock(&fiq->lock);
 252         }
 253 }
 254
 255 static void flush_bg_queue(struct fuse_conn *fc)
 256 {
 257         struct fuse_iqueue *fiq = &fc->iq;
 258
 259         while (fc->active_background < fc->max_background &&
 260                !list_empty(&fc->bg_queue)) {
 261                 struct fuse_req *req;
 262
 263                 req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
 264                 list_del(&req->list);
 265                 fc->active_background++;
 266                 spin_lock(&fiq->lock);
 267                 req->in.h.unique = fuse_get_unique(fiq);
 268                 queue_request_and_unlock(fiq, req);
 269         }
 270 }
 271
 272 /*
 273  * This function is called when a request is finished.  Either a reply
 274  * has arrived or it was aborted (and not yet sent) or some error
 275  * occurred during communication with userspace, or the device file
 276  * was closed.  The requester thread is woken up (if still waiting),
 277  * the 'end' callback is called if given, else the reference to the
 278  * request is released
 279  */
 280 void fuse_request_end(struct fuse_req *req)
 281 {
 282         struct fuse_mount *fm = req->fm;
 283         struct fuse_conn *fc = fm->fc;
 284         struct fuse_iqueue *fiq = &fc->iq;
 285
 286         if (test_and_set_bit(FR_FINISHED, &req->flags))
 287                 goto put_request;
 288
 289         /*
 290          * test_and_set_bit() implies smp_mb() between bit
 291          * changing and below intr_entry check. Pairs with
 292          * smp_mb() from queue_interrupt().
 293          */
 294         if (!list_empty(&req->intr_entry)) {
 295                 spin_lock(&fiq->lock);
 296                 list_del_init(&req->intr_entry);
 297                 spin_unlock(&fiq->lock);
 298         }
 299         WARN_ON(test_bit(FR_PENDING, &req->flags));
 300         WARN_ON(test_bit(FR_SENT, &req->flags));
 301         if (test_bit(FR_BACKGROUND, &req->flags)) {
 302                 spin_lock(&fc->bg_lock);
 303                 clear_bit(FR_BACKGROUND, &req->flags);
 304                 if (fc->num_background == fc->max_background) {
 305                         fc->blocked = 0;
 306                         wake_up(&fc->blocked_waitq);
 307                 } else if (!fc->blocked) {
 308                         /*
 309                          * Wake up next waiter, if any.  It's okay to use
 310                          * waitqueue_active(), as we've already synced up
 311                          * fc->blocked with waiters with the wake_up() call
 312                          * above.
 313                          */
 314                         if (waitqueue_active(&fc->blocked_waitq))
 315                                 wake_up(&fc->blocked_waitq);
 316                 }
 317
 318                 if (fc->num_background == fc->congestion_threshold && fm->sb) {
 319                         clear_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC);
 320                         clear_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC);
 321                 }
 322                 fc->num_background--;
 323                 fc->active_background--;
 324                 flush_bg_queue(fc);
 325                 spin_unlock(&fc->bg_lock);
 326         } else {
 327                 /* Wake up waiter sleeping in request_wait_answer() */
 328                 wake_up(&req->waitq);
 329         }
 330
 331         if (test_bit(FR_ASYNC, &req->flags))
 332                 req->args->end(fm, req->args, req->out.h.error);
 333 put_request:
 334         fuse_put_request(req);
 335 }
 336 EXPORT_SYMBOL_GPL(fuse_request_end);
 337
 338 static int queue_interrupt(struct fuse_req *req)
 339 {
 340         struct fuse_iqueue *fiq = &req->fm->fc->iq;
 341
 342         spin_lock(&fiq->lock);
 343         /* Check for we've sent request to interrupt this req */
 344         if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
 345                 spin_unlock(&fiq->lock);
 346                 return -EINVAL;
 347         }
 348
 349         if (list_empty(&req->intr_entry)) {
 350                 list_add_tail(&req->intr_entry, &fiq->interrupts);
 351                 /*
 352                  * Pairs with smp_mb() implied by test_and_set_bit()
 353                  * from fuse_request_end().
 354                  */
 355                 smp_mb();
 356                 if (test_bit(FR_FINISHED, &req->flags)) {
 357                         list_del_init(&req->intr_entry);
 358                         spin_unlock(&fiq->lock);
 359                         return 0;
 360                 }
 361                 fiq->ops->wake_interrupt_and_unlock(fiq);
 362         } else {
 363                 spin_unlock(&fiq->lock);
 364         }
 365         return 0;
 366 }
 367
 368 static void request_wait_answer(struct fuse_req *req)
 369 {
 370         struct fuse_conn *fc = req->fm->fc;
 371         struct fuse_iqueue *fiq = &fc->iq;
 372         int err;
 373
 374         if (!fc->no_interrupt) {
 375                 /* Any signal may interrupt this */
 376                 err = wait_event_interruptible(req->waitq,
 377                                         test_bit(FR_FINISHED, &req->flags));
 378                 if (!err)
 379                         return;
 380
 381                 set_bit(FR_INTERRUPTED, &req->flags);
 382                 /* matches barrier in fuse_dev_do_read() */
 383                 smp_mb__after_atomic();
 384                 if (test_bit(FR_SENT, &req->flags))
 385                         queue_interrupt(req);
 386         }
 387
 388         if (!test_bit(FR_FORCE, &req->flags)) {
 389                 /* Only fatal signals may interrupt this */
 390                 err = wait_event_killable(req->waitq,
 391                                         test_bit(FR_FINISHED, &req->flags));
 392                 if (!err)
 393                         return;
 394
 395                 spin_lock(&fiq->lock);
 396                 /* Request is not yet in userspace, bail out */
 397                 if (test_bit(FR_PENDING, &req->flags)) {
 398                         list_del(&req->list);
 399                         spin_unlock(&fiq->lock);
 400                         __fuse_put_request(req);
 401                         req->out.h.error = -EINTR;
 402                         return;
 403                 }
 404                 spin_unlock(&fiq->lock);
 405         }
 406
 407         /*
 408          * Either request is already in userspace, or it was forced.
 409          * Wait it out.
 410          */
 411         wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
 412 }
 413
 414 static void __fuse_request_send(struct fuse_req *req)
 415 {
 416         struct fuse_iqueue *fiq = &req->fm->fc->iq;
 417
 418         BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
 419         spin_lock(&fiq->lock);
 420         if (!fiq->connected) {
 421                 spin_unlock(&fiq->lock);
 422                 req->out.h.error = -ENOTCONN;
 423         } else {
 424                 req->in.h.unique = fuse_get_unique(fiq);
 425                 /* acquire extra reference, since request is still needed
 426                    after fuse_request_end() */
 427                 __fuse_get_request(req);
 428                 queue_request_and_unlock(fiq, req);
 429
 430                 request_wait_answer(req);
 431                 /* Pairs with smp_wmb() in fuse_request_end() */
 432                 smp_rmb();
 433         }
 434 }
 435
 436 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
 437 {
 438         if (fc->minor < 4 && args->opcode == FUSE_STATFS)
 439                 args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
 440
 441         if (fc->minor < 9) {
 442                 switch (args->opcode) {
 443                 case FUSE_LOOKUP:
 444                 case FUSE_CREATE:
 445                 case FUSE_MKNOD:
 446                 case FUSE_MKDIR:
 447                 case FUSE_SYMLINK:
 448                 case FUSE_LINK:
 449                         args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 450                         break;
 451                 case FUSE_GETATTR:
 452                 case FUSE_SETATTR:
 453                         args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 454                         break;
 455                 }
 456         }
 457         if (fc->minor < 12) {
 458                 switch (args->opcode) {
 459                 case FUSE_CREATE:
 460                         args->in_args[0].size = sizeof(struct fuse_open_in);
 461                         break;
 462                 case FUSE_MKNOD:
 463                         args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
 464                         break;
 465                 }
 466         }
 467 }
 468
 469 static void fuse_force_creds(struct fuse_req *req)
 470 {
 471         struct fuse_conn *fc = req->fm->fc;
 472
 473         req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
 474         req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
 475         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 476 }
 477
 478 static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
 479 {
 480         req->in.h.opcode = args->opcode;
 481         req->in.h.nodeid = args->nodeid;
 482         req->args = args;
 483         if (args->end)
 484                 __set_bit(FR_ASYNC, &req->flags);
 485 }
 486
 487 ssize_t fuse_simple_request(struct fuse_mount *fm, struct fuse_args *args)
 488 {
 489         struct fuse_conn *fc = fm->fc;
 490         struct fuse_req *req;
 491         ssize_t ret;
 492
 493         if (args->force) {
 494                 atomic_inc(&fc->num_waiting);
 495                 req = fuse_request_alloc(fm, GFP_KERNEL | __GFP_NOFAIL);
 496
 497                 if (!args->nocreds)
 498                         fuse_force_creds(req);
 499
 500                 __set_bit(FR_WAITING, &req->flags);
 501                 __set_bit(FR_FORCE, &req->flags);
 502         } else {
 503                 WARN_ON(args->nocreds);
 504                 req = fuse_get_req(fm, false);
 505                 if (IS_ERR(req))
 506                         return PTR_ERR(req);
 507         }
 508
 509         /* Needs to be done after fuse_get_req() so that fc->minor is valid */
 510         fuse_adjust_compat(fc, args);
 511         fuse_args_to_req(req, args);
 512
 513         if (!args->noreply)
 514                 __set_bit(FR_ISREPLY, &req->flags);
 515         __fuse_request_send(req);
 516         ret = req->out.h.error;
 517         if (!ret && args->out_argvar) {
 518                 BUG_ON(args->out_numargs == 0);
 519                 ret = args->out_args[args->out_numargs - 1].size;
 520         }
 521         fuse_put_request(req);
 522
 523         return ret;
 524 }
 525
 526 static bool fuse_request_queue_background(struct fuse_req *req)
 527 {
 528         struct fuse_mount *fm = req->fm;
 529         struct fuse_conn *fc = fm->fc;
 530         bool queued = false;
 531
 532         WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
 533         if (!test_bit(FR_WAITING, &req->flags)) {
 534                 __set_bit(FR_WAITING, &req->flags);
 535                 atomic_inc(&fc->num_waiting);
 536         }
 537         __set_bit(FR_ISREPLY, &req->flags);
 538         spin_lock(&fc->bg_lock);
 539         if (likely(fc->connected)) {
 540                 fc->num_background++;
 541                 if (fc->num_background == fc->max_background)
 542                         fc->blocked = 1;
 543                 if (fc->num_background == fc->congestion_threshold && fm->sb) {
 544                         set_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC);
 545                         set_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC);
 546                 }
 547                 list_add_tail(&req->list, &fc->bg_queue);
 548                 flush_bg_queue(fc);
 549                 queued = true;
 550         }
 551         spin_unlock(&fc->bg_lock);
 552
 553         return queued;
 554 }
 555
 556 int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
 557                             gfp_t gfp_flags)
 558 {
 559         struct fuse_req *req;
 560
 561         if (args->force) {
 562                 WARN_ON(!args->nocreds);
 563                 req = fuse_request_alloc(fm, gfp_flags);
 564                 if (!req)
 565                         return -ENOMEM;
 566                 __set_bit(FR_BACKGROUND, &req->flags);
 567         } else {
 568                 WARN_ON(args->nocreds);
 569                 req = fuse_get_req(fm, true);
 570                 if (IS_ERR(req))
 571                         return PTR_ERR(req);
 572         }
 573
 574         fuse_args_to_req(req, args);
 575
 576         if (!fuse_request_queue_background(req)) {
 577                 fuse_put_request(req);
 578                 return -ENOTCONN;
 579         }
 580
 581         return 0;
 582 }
 583 EXPORT_SYMBOL_GPL(fuse_simple_background);
 584
 585 static int fuse_simple_notify_reply(struct fuse_mount *fm,
 586                                     struct fuse_args *args, u64 unique)
 587 {
 588         struct fuse_req *req;
 589         struct fuse_iqueue *fiq = &fm->fc->iq;
 590         int err = 0;
 591
 592         req = fuse_get_req(fm, false);
 593         if (IS_ERR(req))
 594                 return PTR_ERR(req);
 595
 596         __clear_bit(FR_ISREPLY, &req->flags);
 597         req->in.h.unique = unique;
 598
 599         fuse_args_to_req(req, args);
 600
 601         spin_lock(&fiq->lock);
 602         if (fiq->connected) {
 603                 queue_request_and_unlock(fiq, req);
 604         } else {
 605                 err = -ENODEV;
 606                 spin_unlock(&fiq->lock);
 607                 fuse_put_request(req);
 608         }
 609
 610         return err;
 611 }
 612
 613 /*
 614  * Lock the request.  Up to the next unlock_request() there mustn't be
 615  * anything that could cause a page-fault.  If the request was already
 616  * aborted bail out.
 617  */
 618 static int lock_request(struct fuse_req *req)
 619 {
 620         int err = 0;
 621         if (req) {
 622                 spin_lock(&req->waitq.lock);
 623                 if (test_bit(FR_ABORTED, &req->flags))
 624                         err = -ENOENT;
 625                 else
 626                         set_bit(FR_LOCKED, &req->flags);
 627                 spin_unlock(&req->waitq.lock);
 628         }
 629         return err;
 630 }
 631
 632 /*
 633  * Unlock request.  If it was aborted while locked, caller is responsible
 634  * for unlocking and ending the request.
 635  */
 636 static int unlock_request(struct fuse_req *req)
 637 {
 638         int err = 0;
 639         if (req) {
 640                 spin_lock(&req->waitq.lock);
 641                 if (test_bit(FR_ABORTED, &req->flags))
 642                         err = -ENOENT;
 643                 else
 644                         clear_bit(FR_LOCKED, &req->flags);
 645                 spin_unlock(&req->waitq.lock);
 646         }
 647         return err;
 648 }
 649
 650 struct fuse_copy_state {
 651         int write;
 652         struct fuse_req *req;
 653         struct iov_iter *iter;
 654         struct pipe_buffer *pipebufs;
 655         struct pipe_buffer *currbuf;
 656         struct pipe_inode_info *pipe;
 657         unsigned long nr_segs;
 658         struct page *pg;
 659         unsigned len;
 660         unsigned offset;
 661         unsigned move_pages:1;
 662 };
 663
 664 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
 665                            struct iov_iter *iter)
 666 {
 667         memset(cs, 0, sizeof(*cs));
 668         cs->write = write;
 669         cs->iter = iter;
 670 }
 671
 672 /* Unmap and put previous page of userspace buffer */
 673 static void fuse_copy_finish(struct fuse_copy_state *cs)
 674 {
 675         if (cs->currbuf) {
 676                 struct pipe_buffer *buf = cs->currbuf;
 677
 678                 if (cs->write)
 679                         buf->len = PAGE_SIZE - cs->len;
 680                 cs->currbuf = NULL;
 681         } else if (cs->pg) {
 682                 if (cs->write) {
 683                         flush_dcache_page(cs->pg);
 684                         set_page_dirty_lock(cs->pg);
 685                 }
 686                 put_page(cs->pg);
 687         }
 688         cs->pg = NULL;
 689 }
 690
 691 /*
 692  * Get another pagefull of userspace buffer, and map it to kernel
 693  * address space, and lock request
 694  */
 695 static int fuse_copy_fill(struct fuse_copy_state *cs)
 696 {
 697         struct page *page;
 698         int err;
 699
 700         err = unlock_request(cs->req);
 701         if (err)
 702                 return err;
 703
 704         fuse_copy_finish(cs);
 705         if (cs->pipebufs) {
 706                 struct pipe_buffer *buf = cs->pipebufs;
 707
 708                 if (!cs->write) {
 709                         err = pipe_buf_confirm(cs->pipe, buf);
 710                         if (err)
 711                                 return err;
 712
 713                         BUG_ON(!cs->nr_segs);
 714                         cs->currbuf = buf;
 715                         cs->pg = buf->page;
 716                         cs->offset = buf->offset;
 717                         cs->len = buf->len;
 718                         cs->pipebufs++;
 719                         cs->nr_segs--;
 720                 } else {
 721                         if (cs->nr_segs >= cs->pipe->max_usage)
 722                                 return -EIO;
 723
 724                         page = alloc_page(GFP_HIGHUSER);
 725                         if (!page)
 726                                 return -ENOMEM;
 727
 728                         buf->page = page;
 729                         buf->offset = 0;
 730                         buf->len = 0;
 731
 732                         cs->currbuf = buf;
 733                         cs->pg = page;
 734                         cs->offset = 0;
 735                         cs->len = PAGE_SIZE;
 736                         cs->pipebufs++;
 737                         cs->nr_segs++;
 738                 }
 739         } else {
 740                 size_t off;
 741                 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
 742                 if (err < 0)
 743                         return err;
 744                 BUG_ON(!err);
 745                 cs->len = err;
 746                 cs->offset = off;
 747                 cs->pg = page;
 748                 iov_iter_advance(cs->iter, err);
 749         }
 750
 751         return lock_request(cs->req);
 752 }
 753
 754 /* Do as much copy to/from userspace buffer as we can */
 755 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 756 {
 757         unsigned ncpy = min(*size, cs->len);
 758         if (val) {
 759                 void *pgaddr = kmap_atomic(cs->pg);
 760                 void *buf = pgaddr + cs->offset;
 761
 762                 if (cs->write)
 763                         memcpy(buf, *val, ncpy);
 764                 else
 765                         memcpy(*val, buf, ncpy);
 766
 767                 kunmap_atomic(pgaddr);
 768                 *val += ncpy;
 769         }
 770         *size -= ncpy;
 771         cs->len -= ncpy;
 772         cs->offset += ncpy;
 773         return ncpy;
 774 }
 775
 776 static int fuse_check_page(struct page *page)
 777 {
 778         if (page_mapcount(page) ||
 779             page->mapping != NULL ||
 780             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 781              ~(1 << PG_locked |
 782                1 << PG_referenced |
 783                1 << PG_uptodate |
 784                1 << PG_lru |
 785                1 << PG_active |
 786                1 << PG_reclaim |
 787                1 << PG_waiters))) {
 788                 dump_page(page, "fuse: trying to steal weird page");
 789                 return 1;
 790         }
 791         return 0;
 792 }
 793
 794 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 795 {
 796         int err;
 797         struct page *oldpage = *pagep;
 798         struct page *newpage;
 799         struct pipe_buffer *buf = cs->pipebufs;
 800
 801         get_page(oldpage);
 802         err = unlock_request(cs->req);
 803         if (err)
 804                 goto out_put_old;
 805
 806         fuse_copy_finish(cs);
 807
 808         err = pipe_buf_confirm(cs->pipe, buf);
 809         if (err)
 810                 goto out_put_old;
 811
 812         BUG_ON(!cs->nr_segs);
 813         cs->currbuf = buf;
 814         cs->len = buf->len;
 815         cs->pipebufs++;
 816         cs->nr_segs--;
 817
 818         if (cs->len != PAGE_SIZE)
 819                 goto out_fallback;
 820
 821         if (!pipe_buf_try_steal(cs->pipe, buf))
 822                 goto out_fallback;
 823
 824         newpage = buf->page;
 825
 826         if (!PageUptodate(newpage))
 827                 SetPageUptodate(newpage);
 828
 829         ClearPageMappedToDisk(newpage);
 830
 831         if (fuse_check_page(newpage) != 0)
 832                 goto out_fallback_unlock;
 833
 834         /*
 835          * This is a new and locked page, it shouldn't be mapped or
 836          * have any special flags on it
 837          */
 838         if (WARN_ON(page_mapped(oldpage)))
 839                 goto out_fallback_unlock;
 840         if (WARN_ON(page_has_private(oldpage)))
 841                 goto out_fallback_unlock;
 842         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 843                 goto out_fallback_unlock;
 844         if (WARN_ON(PageMlocked(oldpage)))
 845                 goto out_fallback_unlock;
 846
 847         replace_page_cache_page(oldpage, newpage);
 848
 849         get_page(newpage);
 850
 851         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 852                 lru_cache_add(newpage);
 853
 854         err = 0;
 855         spin_lock(&cs->req->waitq.lock);
 856         if (test_bit(FR_ABORTED, &cs->req->flags))
 857                 err = -ENOENT;
 858         else
 859                 *pagep = newpage;
 860         spin_unlock(&cs->req->waitq.lock);
 861
 862         if (err) {
 863                 unlock_page(newpage);
 864                 put_page(newpage);
 865                 goto out_put_old;
 866         }
 867
 868         unlock_page(oldpage);
 869         /* Drop ref for ap->pages[] array */
 870         put_page(oldpage);
 871         cs->len = 0;
 872
 873         err = 0;
 874 out_put_old:
 875         /* Drop ref obtained in this function */
 876         put_page(oldpage);
 877         return err;
 878
 879 out_fallback_unlock:
 880         unlock_page(newpage);
 881 out_fallback:
 882         cs->pg = buf->page;
 883         cs->offset = buf->offset;
 884
 885         err = lock_request(cs->req);
 886         if (!err)
 887                 err = 1;
 888
 889         goto out_put_old;
 890 }
 891
 892 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 893                          unsigned offset, unsigned count)
 894 {
 895         struct pipe_buffer *buf;
 896         int err;
 897
 898         if (cs->nr_segs >= cs->pipe->max_usage)
 899                 return -EIO;
 900
 901         get_page(page);
 902         err = unlock_request(cs->req);
 903         if (err) {
 904                 put_page(page);
 905                 return err;
 906         }
 907
 908         fuse_copy_finish(cs);
 909
 910         buf = cs->pipebufs;
 911         buf->page = page;
 912         buf->offset = offset;
 913         buf->len = count;
 914
 915         cs->pipebufs++;
 916         cs->nr_segs++;
 917         cs->len = 0;
 918
 919         return 0;
 920 }
 921
 922 /*
 923  * Copy a page in the request to/from the userspace buffer.  Must be
 924  * done atomically
 925  */
 926 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 927                           unsigned offset, unsigned count, int zeroing)
 928 {
 929         int err;
 930         struct page *page = *pagep;
 931
 932         if (page && zeroing && count < PAGE_SIZE)
 933                 clear_highpage(page);
 934
 935         while (count) {
 936                 if (cs->write && cs->pipebufs && page) {
 937                         return fuse_ref_page(cs, page, offset, count);
 938                 } else if (!cs->len) {
 939                         if (cs->move_pages && page &&
 940                             offset == 0 && count == PAGE_SIZE) {
 941                                 err = fuse_try_move_page(cs, pagep);
 942                                 if (err <= 0)
 943                                         return err;
 944                         } else {
 945                                 err = fuse_copy_fill(cs);
 946                                 if (err)
 947                                         return err;
 948                         }
 949                 }
 950                 if (page) {
 951                         void *mapaddr = kmap_atomic(page);
 952                         void *buf = mapaddr + offset;
 953                         offset += fuse_copy_do(cs, &buf, &count);
 954                         kunmap_atomic(mapaddr);
 955                 } else
 956                         offset += fuse_copy_do(cs, NULL, &count);
 957         }
 958         if (page && !cs->write)
 959                 flush_dcache_page(page);
 960         return 0;
 961 }
 962
 963 /* Copy pages in the request to/from userspace buffer */
 964 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 965                            int zeroing)
 966 {
 967         unsigned i;
 968         struct fuse_req *req = cs->req;
 969         struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
 970
 971
 972         for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
 973                 int err;
 974                 unsigned int offset = ap->descs[i].offset;
 975                 unsigned int count = min(nbytes, ap->descs[i].length);
 976
 977                 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
 978                 if (err)
 979                         return err;
 980
 981                 nbytes -= count;
 982         }
 983         return 0;
 984 }
 985
 986 /* Copy a single argument in the request to/from userspace buffer */
 987 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
 988 {
 989         while (size) {
 990                 if (!cs->len) {
 991                         int err = fuse_copy_fill(cs);
 992                         if (err)
 993                                 return err;
 994                 }
 995                 fuse_copy_do(cs, &val, &size);
 996         }
 997         return 0;
 998 }
 999
1000 /* Copy request arguments to/from userspace buffer */
1001 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1002                           unsigned argpages, struct fuse_arg *args,
1003                           int zeroing)
1004 {
1005         int err = 0;
1006         unsigned i;
1007
1008         for (i = 0; !err && i < numargs; i++)  {
1009                 struct fuse_arg *arg = &args[i];
1010                 if (i == numargs - 1 && argpages)
1011                         err = fuse_copy_pages(cs, arg->size, zeroing);
1012                 else
1013                         err = fuse_copy_one(cs, arg->value, arg->size);
1014         }
1015         return err;
1016 }
1017
1018 static int forget_pending(struct fuse_iqueue *fiq)
1019 {
1020         return fiq->forget_list_head.next != NULL;
1021 }
1022
1023 static int request_pending(struct fuse_iqueue *fiq)
1024 {
1025         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1026                 forget_pending(fiq);
1027 }
1028
1029 /*
1030  * Transfer an interrupt request to userspace
1031  *
1032  * Unlike other requests this is assembled on demand, without a need
1033  * to allocate a separate fuse_req structure.
1034  *
1035  * Called with fiq->lock held, releases it
1036  */
1037 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1038                                struct fuse_copy_state *cs,
1039                                size_t nbytes, struct fuse_req *req)
1040 __releases(fiq->lock)
1041 {
1042         struct fuse_in_header ih;
1043         struct fuse_interrupt_in arg;
1044         unsigned reqsize = sizeof(ih) + sizeof(arg);
1045         int err;
1046
1047         list_del_init(&req->intr_entry);
1048         memset(&ih, 0, sizeof(ih));
1049         memset(&arg, 0, sizeof(arg));
1050         ih.len = reqsize;
1051         ih.opcode = FUSE_INTERRUPT;
1052         ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1053         arg.unique = req->in.h.unique;
1054
1055         spin_unlock(&fiq->lock);
1056         if (nbytes < reqsize)
1057                 return -EINVAL;
1058
1059         err = fuse_copy_one(cs, &ih, sizeof(ih));
1060         if (!err)
1061                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1062         fuse_copy_finish(cs);
1063
1064         return err ? err : reqsize;
1065 }
1066
1067 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1068                                              unsigned int max,
1069                                              unsigned int *countp)
1070 {
1071         struct fuse_forget_link *head = fiq->forget_list_head.next;
1072         struct fuse_forget_link **newhead = &head;
1073         unsigned count;
1074
1075         for (count = 0; *newhead != NULL && count < max; count++)
1076                 newhead = &(*newhead)->next;
1077
1078         fiq->forget_list_head.next = *newhead;
1079         *newhead = NULL;
1080         if (fiq->forget_list_head.next == NULL)
1081                 fiq->forget_list_tail = &fiq->forget_list_head;
1082
1083         if (countp != NULL)
1084                 *countp = count;
1085
1086         return head;
1087 }
1088 EXPORT_SYMBOL(fuse_dequeue_forget);
1089
1090 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1091                                    struct fuse_copy_state *cs,
1092                                    size_t nbytes)
1093 __releases(fiq->lock)
1094 {
1095         int err;
1096         struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1097         struct fuse_forget_in arg = {
1098                 .nlookup = forget->forget_one.nlookup,
1099         };
1100         struct fuse_in_header ih = {
1101                 .opcode = FUSE_FORGET,
1102                 .nodeid = forget->forget_one.nodeid,
1103                 .unique = fuse_get_unique(fiq),
1104                 .len = sizeof(ih) + sizeof(arg),
1105         };
1106
1107         spin_unlock(&fiq->lock);
1108         kfree(forget);
1109         if (nbytes < ih.len)
1110                 return -EINVAL;
1111
1112         err = fuse_copy_one(cs, &ih, sizeof(ih));
1113         if (!err)
1114                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1115         fuse_copy_finish(cs);
1116
1117         if (err)
1118                 return err;
1119
1120         return ih.len;
1121 }
1122
1123 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1124                                    struct fuse_copy_state *cs, size_t nbytes)
1125 __releases(fiq->lock)
1126 {
1127         int err;
1128         unsigned max_forgets;
1129         unsigned count;
1130         struct fuse_forget_link *head;
1131         struct fuse_batch_forget_in arg = { .count = 0 };
1132         struct fuse_in_header ih = {
1133                 .opcode = FUSE_BATCH_FORGET,
1134                 .unique = fuse_get_unique(fiq),
1135                 .len = sizeof(ih) + sizeof(arg),
1136         };
1137
1138         if (nbytes < ih.len) {
1139                 spin_unlock(&fiq->lock);
1140                 return -EINVAL;
1141         }
1142
1143         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1144         head = fuse_dequeue_forget(fiq, max_forgets, &count);
1145         spin_unlock(&fiq->lock);
1146
1147         arg.count = count;
1148         ih.len += count * sizeof(struct fuse_forget_one);
1149         err = fuse_copy_one(cs, &ih, sizeof(ih));
1150         if (!err)
1151                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1152
1153         while (head) {
1154                 struct fuse_forget_link *forget = head;
1155
1156                 if (!err) {
1157                         err = fuse_copy_one(cs, &forget->forget_one,
1158                                             sizeof(forget->forget_one));
1159                 }
1160                 head = forget->next;
1161                 kfree(forget);
1162         }
1163
1164         fuse_copy_finish(cs);
1165
1166         if (err)
1167                 return err;
1168
1169         return ih.len;
1170 }
1171
1172 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1173                             struct fuse_copy_state *cs,
1174                             size_t nbytes)
1175 __releases(fiq->lock)
1176 {
1177         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1178                 return fuse_read_single_forget(fiq, cs, nbytes);
1179         else
1180                 return fuse_read_batch_forget(fiq, cs, nbytes);
1181 }
1182
1183 /*
1184  * Read a single request into the userspace filesystem's buffer.  This
1185  * function waits until a request is available, then removes it from
1186  * the pending list and copies request data to userspace buffer.  If
1187  * no reply is needed (FORGET) or request has been aborted or there
1188  * was an error during the copying then it's finished by calling
1189  * fuse_request_end().  Otherwise add it to the processing list, and set
1190  * the 'sent' flag.
1191  */
1192 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1193                                 struct fuse_copy_state *cs, size_t nbytes)
1194 {
1195         ssize_t err;
1196         struct fuse_conn *fc = fud->fc;
1197         struct fuse_iqueue *fiq = &fc->iq;
1198         struct fuse_pqueue *fpq = &fud->pq;
1199         struct fuse_req *req;
1200         struct fuse_args *args;
1201         unsigned reqsize;
1202         unsigned int hash;
1203
1204         /*
1205          * Require sane minimum read buffer - that has capacity for fixed part
1206          * of any request header + negotiated max_write room for data.
1207          *
1208          * Historically libfuse reserves 4K for fixed header room, but e.g.
1209          * GlusterFS reserves only 80 bytes
1210          *
1211          *      = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1212          *
1213          * which is the absolute minimum any sane filesystem should be using
1214          * for header room.
1215          */
1216         if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1217                            sizeof(struct fuse_in_header) +
1218                            sizeof(struct fuse_write_in) +
1219                            fc->max_write))
1220                 return -EINVAL;
1221
1222  restart:
1223         for (;;) {
1224                 spin_lock(&fiq->lock);
1225                 if (!fiq->connected || request_pending(fiq))
1226                         break;
1227                 spin_unlock(&fiq->lock);
1228
1229                 if (file->f_flags & O_NONBLOCK)
1230                         return -EAGAIN;
1231                 err = wait_event_interruptible_exclusive(fiq->waitq,
1232                                 !fiq->connected || request_pending(fiq));
1233                 if (err)
1234                         return err;
1235         }
1236
1237         if (!fiq->connected) {
1238                 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1239                 goto err_unlock;
1240         }
1241
1242         if (!list_empty(&fiq->interrupts)) {
1243                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1244                                  intr_entry);
1245                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1246         }
1247
1248         if (forget_pending(fiq)) {
1249                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1250                         return fuse_read_forget(fc, fiq, cs, nbytes);
1251
1252                 if (fiq->forget_batch <= -8)
1253                         fiq->forget_batch = 16;
1254         }
1255
1256         req = list_entry(fiq->pending.next, struct fuse_req, list);
1257         clear_bit(FR_PENDING, &req->flags);
1258         list_del_init(&req->list);
1259         spin_unlock(&fiq->lock);
1260
1261         args = req->args;
1262         reqsize = req->in.h.len;
1263
1264         /* If request is too large, reply with an error and restart the read */
1265         if (nbytes < reqsize) {
1266                 req->out.h.error = -EIO;
1267                 /* SETXATTR is special, since it may contain too large data */
1268                 if (args->opcode == FUSE_SETXATTR)
1269                         req->out.h.error = -E2BIG;
1270                 fuse_request_end(req);
1271                 goto restart;
1272         }
1273         spin_lock(&fpq->lock);
1274         list_add(&req->list, &fpq->io);
1275         spin_unlock(&fpq->lock);
1276         cs->req = req;
1277         err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1278         if (!err)
1279                 err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1280                                      (struct fuse_arg *) args->in_args, 0);
1281         fuse_copy_finish(cs);
1282         spin_lock(&fpq->lock);
1283         clear_bit(FR_LOCKED, &req->flags);
1284         if (!fpq->connected) {
1285                 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1286                 goto out_end;
1287         }
1288         if (err) {
1289                 req->out.h.error = -EIO;
1290                 goto out_end;
1291         }
1292         if (!test_bit(FR_ISREPLY, &req->flags)) {
1293                 err = reqsize;
1294                 goto out_end;
1295         }
1296         hash = fuse_req_hash(req->in.h.unique);
1297         list_move_tail(&req->list, &fpq->processing[hash]);
1298         __fuse_get_request(req);
1299         set_bit(FR_SENT, &req->flags);
1300         spin_unlock(&fpq->lock);
1301         /* matches barrier in request_wait_answer() */
1302         smp_mb__after_atomic();
1303         if (test_bit(FR_INTERRUPTED, &req->flags))
1304                 queue_interrupt(req);
1305         fuse_put_request(req);
1306
1307         return reqsize;
1308
1309 out_end:
1310         if (!test_bit(FR_PRIVATE, &req->flags))
1311                 list_del_init(&req->list);
1312         spin_unlock(&fpq->lock);
1313         fuse_request_end(req);
1314         return err;
1315
1316  err_unlock:
1317         spin_unlock(&fiq->lock);
1318         return err;
1319 }
1320
1321 static int fuse_dev_open(struct inode *inode, struct file *file)
1322 {
1323         /*
1324          * The fuse device's file's private_data is used to hold
1325          * the fuse_conn(ection) when it is mounted, and is used to
1326          * keep track of whether the file has been mounted already.
1327          */
1328         file->private_data = NULL;
1329         return 0;
1330 }
1331
1332 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1333 {
1334         struct fuse_copy_state cs;
1335         struct file *file = iocb->ki_filp;
1336         struct fuse_dev *fud = fuse_get_dev(file);
1337
1338         if (!fud)
1339                 return -EPERM;
1340
1341         if (!iter_is_iovec(to))
1342                 return -EINVAL;
1343
1344         fuse_copy_init(&cs, 1, to);
1345
1346         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1347 }
1348
1349 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1350                                     struct pipe_inode_info *pipe,
1351                                     size_t len, unsigned int flags)
1352 {
1353         int total, ret;
1354         int page_nr = 0;
1355         struct pipe_buffer *bufs;
1356         struct fuse_copy_state cs;
1357         struct fuse_dev *fud = fuse_get_dev(in);
1358
1359         if (!fud)
1360                 return -EPERM;
1361
1362         bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer),
1363                               GFP_KERNEL);
1364         if (!bufs)
1365                 return -ENOMEM;
1366
1367         fuse_copy_init(&cs, 1, NULL);
1368         cs.pipebufs = bufs;
1369         cs.pipe = pipe;
1370         ret = fuse_dev_do_read(fud, in, &cs, len);
1371         if (ret < 0)
1372                 goto out;
1373
1374         if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
1375                 ret = -EIO;
1376                 goto out;
1377         }
1378
1379         for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1380                 /*
1381                  * Need to be careful about this.  Having buf->ops in module
1382                  * code can Oops if the buffer persists after module unload.
1383                  */
1384                 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1385                 bufs[page_nr].flags = 0;
1386                 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1387                 if (unlikely(ret < 0))
1388                         break;
1389         }
1390         if (total)
1391                 ret = total;
1392 out:
1393         for (; page_nr < cs.nr_segs; page_nr++)
1394                 put_page(bufs[page_nr].page);
1395
1396         kvfree(bufs);
1397         return ret;
1398 }
1399
1400 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1401                             struct fuse_copy_state *cs)
1402 {
1403         struct fuse_notify_poll_wakeup_out outarg;
1404         int err = -EINVAL;
1405
1406         if (size != sizeof(outarg))
1407                 goto err;
1408
1409         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1410         if (err)
1411                 goto err;
1412
1413         fuse_copy_finish(cs);
1414         return fuse_notify_poll_wakeup(fc, &outarg);
1415
1416 err:
1417         fuse_copy_finish(cs);
1418         return err;
1419 }
1420
1421 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1422                                    struct fuse_copy_state *cs)
1423 {
1424         struct fuse_notify_inval_inode_out outarg;
1425         int err = -EINVAL;
1426
1427         if (size != sizeof(outarg))
1428                 goto err;
1429
1430         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1431         if (err)
1432                 goto err;
1433         fuse_copy_finish(cs);
1434
1435         down_read(&fc->killsb);
1436         err = fuse_reverse_inval_inode(fc, outarg.ino,
1437                                        outarg.off, outarg.len);
1438         up_read(&fc->killsb);
1439         return err;
1440
1441 err:
1442         fuse_copy_finish(cs);
1443         return err;
1444 }
1445
1446 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1447                                    struct fuse_copy_state *cs)
1448 {
1449         struct fuse_notify_inval_entry_out outarg;
1450         int err = -ENOMEM;
1451         char *buf;
1452         struct qstr name;
1453
1454         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1455         if (!buf)
1456                 goto err;
1457
1458         err = -EINVAL;
1459         if (size < sizeof(outarg))
1460                 goto err;
1461
1462         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1463         if (err)
1464                 goto err;
1465
1466         err = -ENAMETOOLONG;
1467         if (outarg.namelen > FUSE_NAME_MAX)
1468                 goto err;
1469
1470         err = -EINVAL;
1471         if (size != sizeof(outarg) + outarg.namelen + 1)
1472                 goto err;
1473
1474         name.name = buf;
1475         name.len = outarg.namelen;
1476         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1477         if (err)
1478                 goto err;
1479         fuse_copy_finish(cs);
1480         buf[outarg.namelen] = 0;
1481
1482         down_read(&fc->killsb);
1483         err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name);
1484         up_read(&fc->killsb);
1485         kfree(buf);
1486         return err;
1487
1488 err:
1489         kfree(buf);
1490         fuse_copy_finish(cs);
1491         return err;
1492 }
1493
1494 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1495                               struct fuse_copy_state *cs)
1496 {
1497         struct fuse_notify_delete_out outarg;
1498         int err = -ENOMEM;
1499         char *buf;
1500         struct qstr name;
1501
1502         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1503         if (!buf)
1504                 goto err;
1505
1506         err = -EINVAL;
1507         if (size < sizeof(outarg))
1508                 goto err;
1509
1510         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1511         if (err)
1512                 goto err;
1513
1514         err = -ENAMETOOLONG;
1515         if (outarg.namelen > FUSE_NAME_MAX)
1516                 goto err;
1517
1518         err = -EINVAL;
1519         if (size != sizeof(outarg) + outarg.namelen + 1)
1520                 goto err;
1521
1522         name.name = buf;
1523         name.len = outarg.namelen;
1524         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1525         if (err)
1526                 goto err;
1527         fuse_copy_finish(cs);
1528         buf[outarg.namelen] = 0;
1529
1530         down_read(&fc->killsb);
1531         err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name);
1532         up_read(&fc->killsb);
1533         kfree(buf);
1534         return err;
1535
1536 err:
1537         kfree(buf);
1538         fuse_copy_finish(cs);
1539         return err;
1540 }
1541
1542 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1543                              struct fuse_copy_state *cs)
1544 {
1545         struct fuse_notify_store_out outarg;
1546         struct inode *inode;
1547         struct address_space *mapping;
1548         u64 nodeid;
1549         int err;
1550         pgoff_t index;
1551         unsigned int offset;
1552         unsigned int num;
1553         loff_t file_size;
1554         loff_t end;
1555
1556         err = -EINVAL;
1557         if (size < sizeof(outarg))
1558                 goto out_finish;
1559
1560         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1561         if (err)
1562                 goto out_finish;
1563
1564         err = -EINVAL;
1565         if (size - sizeof(outarg) != outarg.size)
1566                 goto out_finish;
1567
1568         nodeid = outarg.nodeid;
1569
1570         down_read(&fc->killsb);
1571
1572         err = -ENOENT;
1573         inode = fuse_ilookup(fc, nodeid,  NULL);
1574         if (!inode)
1575                 goto out_up_killsb;
1576
1577         mapping = inode->i_mapping;
1578         index = outarg.offset >> PAGE_SHIFT;
1579         offset = outarg.offset & ~PAGE_MASK;
1580         file_size = i_size_read(inode);
1581         end = outarg.offset + outarg.size;
1582         if (end > file_size) {
1583                 file_size = end;
1584                 fuse_write_update_size(inode, file_size);
1585         }
1586
1587         num = outarg.size;
1588         while (num) {
1589                 struct page *page;
1590                 unsigned int this_num;
1591
1592                 err = -ENOMEM;
1593                 page = find_or_create_page(mapping, index,
1594                                            mapping_gfp_mask(mapping));
1595                 if (!page)
1596                         goto out_iput;
1597
1598                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1599                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1600                 if (!err && offset == 0 &&
1601                     (this_num == PAGE_SIZE || file_size == end))
1602                         SetPageUptodate(page);
1603                 unlock_page(page);
1604                 put_page(page);
1605
1606                 if (err)
1607                         goto out_iput;
1608
1609                 num -= this_num;
1610                 offset = 0;
1611                 index++;
1612         }
1613
1614         err = 0;
1615
1616 out_iput:
1617         iput(inode);
1618 out_up_killsb:
1619         up_read(&fc->killsb);
1620 out_finish:
1621         fuse_copy_finish(cs);
1622         return err;
1623 }
1624
1625 struct fuse_retrieve_args {
1626         struct fuse_args_pages ap;
1627         struct fuse_notify_retrieve_in inarg;
1628 };
1629
1630 static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
1631                               int error)
1632 {
1633         struct fuse_retrieve_args *ra =
1634                 container_of(args, typeof(*ra), ap.args);
1635
1636         release_pages(ra->ap.pages, ra->ap.num_pages);
1637         kfree(ra);
1638 }
1639
1640 static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
1641                          struct fuse_notify_retrieve_out *outarg)
1642 {
1643         int err;
1644         struct address_space *mapping = inode->i_mapping;
1645         pgoff_t index;
1646         loff_t file_size;
1647         unsigned int num;
1648         unsigned int offset;
1649         size_t total_len = 0;
1650         unsigned int num_pages;
1651         struct fuse_conn *fc = fm->fc;
1652         struct fuse_retrieve_args *ra;
1653         size_t args_size = sizeof(*ra);
1654         struct fuse_args_pages *ap;
1655         struct fuse_args *args;
1656
1657         offset = outarg->offset & ~PAGE_MASK;
1658         file_size = i_size_read(inode);
1659
1660         num = min(outarg->size, fc->max_write);
1661         if (outarg->offset > file_size)
1662                 num = 0;
1663         else if (outarg->offset + num > file_size)
1664                 num = file_size - outarg->offset;
1665
1666         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1667         num_pages = min(num_pages, fc->max_pages);
1668
1669         args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1670
1671         ra = kzalloc(args_size, GFP_KERNEL);
1672         if (!ra)
1673                 return -ENOMEM;
1674
1675         ap = &ra->ap;
1676         ap->pages = (void *) (ra + 1);
1677         ap->descs = (void *) (ap->pages + num_pages);
1678
1679         args = &ap->args;
1680         args->nodeid = outarg->nodeid;
1681         args->opcode = FUSE_NOTIFY_REPLY;
1682         args->in_numargs = 2;
1683         args->in_pages = true;
1684         args->end = fuse_retrieve_end;
1685
1686         index = outarg->offset >> PAGE_SHIFT;
1687
1688         while (num && ap->num_pages < num_pages) {
1689                 struct page *page;
1690                 unsigned int this_num;
1691
1692                 page = find_get_page(mapping, index);
1693                 if (!page)
1694                         break;
1695
1696                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1697                 ap->pages[ap->num_pages] = page;
1698                 ap->descs[ap->num_pages].offset = offset;
1699                 ap->descs[ap->num_pages].length = this_num;
1700                 ap->num_pages++;
1701
1702                 offset = 0;
1703                 num -= this_num;
1704                 total_len += this_num;
1705                 index++;
1706         }
1707         ra->inarg.offset = outarg->offset;
1708         ra->inarg.size = total_len;
1709         args->in_args[0].size = sizeof(ra->inarg);
1710         args->in_args[0].value = &ra->inarg;
1711         args->in_args[1].size = total_len;
1712
1713         err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
1714         if (err)
1715                 fuse_retrieve_end(fm, args, err);
1716
1717         return err;
1718 }
1719
1720 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1721                                 struct fuse_copy_state *cs)
1722 {
1723         struct fuse_notify_retrieve_out outarg;
1724         struct fuse_mount *fm;
1725         struct inode *inode;
1726         u64 nodeid;
1727         int err;
1728
1729         err = -EINVAL;
1730         if (size != sizeof(outarg))
1731                 goto copy_finish;
1732
1733         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1734         if (err)
1735                 goto copy_finish;
1736
1737         fuse_copy_finish(cs);
1738
1739         down_read(&fc->killsb);
1740         err = -ENOENT;
1741         nodeid = outarg.nodeid;
1742
1743         inode = fuse_ilookup(fc, nodeid, &fm);
1744         if (inode) {
1745                 err = fuse_retrieve(fm, inode, &outarg);
1746                 iput(inode);
1747         }
1748         up_read(&fc->killsb);
1749
1750         return err;
1751
1752 copy_finish:
1753         fuse_copy_finish(cs);
1754         return err;
1755 }
1756
1757 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1758                        unsigned int size, struct fuse_copy_state *cs)
1759 {
1760         /* Don't try to move pages (yet) */
1761         cs->move_pages = 0;
1762
1763         switch (code) {
1764         case FUSE_NOTIFY_POLL:
1765                 return fuse_notify_poll(fc, size, cs);
1766
1767         case FUSE_NOTIFY_INVAL_INODE:
1768                 return fuse_notify_inval_inode(fc, size, cs);
1769
1770         case FUSE_NOTIFY_INVAL_ENTRY:
1771                 return fuse_notify_inval_entry(fc, size, cs);
1772
1773         case FUSE_NOTIFY_STORE:
1774                 return fuse_notify_store(fc, size, cs);
1775
1776         case FUSE_NOTIFY_RETRIEVE:
1777                 return fuse_notify_retrieve(fc, size, cs);
1778
1779         case FUSE_NOTIFY_DELETE:
1780                 return fuse_notify_delete(fc, size, cs);
1781
1782         default:
1783                 fuse_copy_finish(cs);
1784                 return -EINVAL;
1785         }
1786 }
1787
1788 /* Look up request on processing list by unique ID */
1789 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1790 {
1791         unsigned int hash = fuse_req_hash(unique);
1792         struct fuse_req *req;
1793
1794         list_for_each_entry(req, &fpq->processing[hash], list) {
1795                 if (req->in.h.unique == unique)
1796                         return req;
1797         }
1798         return NULL;
1799 }
1800
1801 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1802                          unsigned nbytes)
1803 {
1804         unsigned reqsize = sizeof(struct fuse_out_header);
1805
1806         reqsize += fuse_len_args(args->out_numargs, args->out_args);
1807
1808         if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1809                 return -EINVAL;
1810         else if (reqsize > nbytes) {
1811                 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1812                 unsigned diffsize = reqsize - nbytes;
1813
1814                 if (diffsize > lastarg->size)
1815                         return -EINVAL;
1816                 lastarg->size -= diffsize;
1817         }
1818         return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1819                               args->out_args, args->page_zeroing);
1820 }
1821
1822 /*
1823  * Write a single reply to a request.  First the header is copied from
1824  * the write buffer.  The request is then searched on the processing
1825  * list by the unique ID found in the header.  If found, then remove
1826  * it from the list and copy the rest of the buffer to the request.
1827  * The request is finished by calling fuse_request_end().
1828  */
1829 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1830                                  struct fuse_copy_state *cs, size_t nbytes)
1831 {
1832         int err;
1833         struct fuse_conn *fc = fud->fc;
1834         struct fuse_pqueue *fpq = &fud->pq;
1835         struct fuse_req *req;
1836         struct fuse_out_header oh;
1837
1838         err = -EINVAL;
1839         if (nbytes < sizeof(struct fuse_out_header))
1840                 goto out;
1841
1842         err = fuse_copy_one(cs, &oh, sizeof(oh));
1843         if (err)
1844                 goto copy_finish;
1845
1846         err = -EINVAL;
1847         if (oh.len != nbytes)
1848                 goto copy_finish;
1849
1850         /*
1851          * Zero oh.unique indicates unsolicited notification message
1852          * and error contains notification code.
1853          */
1854         if (!oh.unique) {
1855                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1856                 goto out;
1857         }
1858
1859         err = -EINVAL;
1860         if (oh.error <= -1000 || oh.error > 0)
1861                 goto copy_finish;
1862
1863         spin_lock(&fpq->lock);
1864         req = NULL;
1865         if (fpq->connected)
1866                 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1867
1868         err = -ENOENT;
1869         if (!req) {
1870                 spin_unlock(&fpq->lock);
1871                 goto copy_finish;
1872         }
1873
1874         /* Is it an interrupt reply ID? */
1875         if (oh.unique & FUSE_INT_REQ_BIT) {
1876                 __fuse_get_request(req);
1877                 spin_unlock(&fpq->lock);
1878
1879                 err = 0;
1880                 if (nbytes != sizeof(struct fuse_out_header))
1881                         err = -EINVAL;
1882                 else if (oh.error == -ENOSYS)
1883                         fc->no_interrupt = 1;
1884                 else if (oh.error == -EAGAIN)
1885                         err = queue_interrupt(req);
1886
1887                 fuse_put_request(req);
1888
1889                 goto copy_finish;
1890         }
1891
1892         clear_bit(FR_SENT, &req->flags);
1893         list_move(&req->list, &fpq->io);
1894         req->out.h = oh;
1895         set_bit(FR_LOCKED, &req->flags);
1896         spin_unlock(&fpq->lock);
1897         cs->req = req;
1898         if (!req->args->page_replace)
1899                 cs->move_pages = 0;
1900
1901         if (oh.error)
1902                 err = nbytes != sizeof(oh) ? -EINVAL : 0;
1903         else
1904                 err = copy_out_args(cs, req->args, nbytes);
1905         fuse_copy_finish(cs);
1906
1907         spin_lock(&fpq->lock);
1908         clear_bit(FR_LOCKED, &req->flags);
1909         if (!fpq->connected)
1910                 err = -ENOENT;
1911         else if (err)
1912                 req->out.h.error = -EIO;
1913         if (!test_bit(FR_PRIVATE, &req->flags))
1914                 list_del_init(&req->list);
1915         spin_unlock(&fpq->lock);
1916
1917         fuse_request_end(req);
1918 out:
1919         return err ? err : nbytes;
1920
1921 copy_finish:
1922         fuse_copy_finish(cs);
1923         goto out;
1924 }
1925
1926 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1927 {
1928         struct fuse_copy_state cs;
1929         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1930
1931         if (!fud)
1932                 return -EPERM;
1933
1934         if (!iter_is_iovec(from))
1935                 return -EINVAL;
1936
1937         fuse_copy_init(&cs, 0, from);
1938
1939         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1940 }
1941
1942 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1943                                      struct file *out, loff_t *ppos,
1944                                      size_t len, unsigned int flags)
1945 {
1946         unsigned int head, tail, mask, count;
1947         unsigned nbuf;
1948         unsigned idx;
1949         struct pipe_buffer *bufs;
1950         struct fuse_copy_state cs;
1951         struct fuse_dev *fud;
1952         size_t rem;
1953         ssize_t ret;
1954
1955         fud = fuse_get_dev(out);
1956         if (!fud)
1957                 return -EPERM;
1958
1959         pipe_lock(pipe);
1960
1961         head = pipe->head;
1962         tail = pipe->tail;
1963         mask = pipe->ring_size - 1;
1964         count = head - tail;
1965
1966         bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
1967         if (!bufs) {
1968                 pipe_unlock(pipe);
1969                 return -ENOMEM;
1970         }
1971
1972         nbuf = 0;
1973         rem = 0;
1974         for (idx = tail; idx != head && rem < len; idx++)
1975                 rem += pipe->bufs[idx & mask].len;
1976
1977         ret = -EINVAL;
1978         if (rem < len)
1979                 goto out_free;
1980
1981         rem = len;
1982         while (rem) {
1983                 struct pipe_buffer *ibuf;
1984                 struct pipe_buffer *obuf;
1985
1986                 if (WARN_ON(nbuf >= count || tail == head))
1987                         goto out_free;
1988
1989                 ibuf = &pipe->bufs[tail & mask];
1990                 obuf = &bufs[nbuf];
1991
1992                 if (rem >= ibuf->len) {
1993                         *obuf = *ibuf;
1994                         ibuf->ops = NULL;
1995                         tail++;
1996                         pipe->tail = tail;
1997                 } else {
1998                         if (!pipe_buf_get(pipe, ibuf))
1999                                 goto out_free;
2000
2001                         *obuf = *ibuf;
2002                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2003                         obuf->len = rem;
2004                         ibuf->offset += obuf->len;
2005                         ibuf->len -= obuf->len;
2006                 }
2007                 nbuf++;
2008                 rem -= obuf->len;
2009         }
2010         pipe_unlock(pipe);
2011
2012         fuse_copy_init(&cs, 0, NULL);
2013         cs.pipebufs = bufs;
2014         cs.nr_segs = nbuf;
2015         cs.pipe = pipe;
2016
2017         if (flags & SPLICE_F_MOVE)
2018                 cs.move_pages = 1;
2019
2020         ret = fuse_dev_do_write(fud, &cs, len);
2021
2022         pipe_lock(pipe);
2023 out_free:
2024         for (idx = 0; idx < nbuf; idx++)
2025                 pipe_buf_release(pipe, &bufs[idx]);
2026         pipe_unlock(pipe);
2027
2028         kvfree(bufs);
2029         return ret;
2030 }
2031
2032 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2033 {
2034         __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2035         struct fuse_iqueue *fiq;
2036         struct fuse_dev *fud = fuse_get_dev(file);
2037
2038         if (!fud)
2039                 return EPOLLERR;
2040
2041         fiq = &fud->fc->iq;
2042         poll_wait(file, &fiq->waitq, wait);
2043
2044         spin_lock(&fiq->lock);
2045         if (!fiq->connected)
2046                 mask = EPOLLERR;
2047         else if (request_pending(fiq))
2048                 mask |= EPOLLIN | EPOLLRDNORM;
2049         spin_unlock(&fiq->lock);
2050
2051         return mask;
2052 }
2053
2054 /* Abort all requests on the given list (pending or processing) */
2055 static void end_requests(struct list_head *head)
2056 {
2057         while (!list_empty(head)) {
2058                 struct fuse_req *req;
2059                 req = list_entry(head->next, struct fuse_req, list);
2060                 req->out.h.error = -ECONNABORTED;
2061                 clear_bit(FR_SENT, &req->flags);
2062                 list_del_init(&req->list);
2063                 fuse_request_end(req);
2064         }
2065 }
2066
2067 static void end_polls(struct fuse_conn *fc)
2068 {
2069         struct rb_node *p;
2070
2071         p = rb_first(&fc->polled_files);
2072
2073         while (p) {
2074                 struct fuse_file *ff;
2075                 ff = rb_entry(p, struct fuse_file, polled_node);
2076                 wake_up_interruptible_all(&ff->poll_wait);
2077
2078                 p = rb_next(p);
2079         }
2080 }
2081
2082 /*
2083  * Abort all requests.
2084  *
2085  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2086  * filesystem.
2087  *
2088  * The same effect is usually achievable through killing the filesystem daemon
2089  * and all users of the filesystem.  The exception is the combination of an
2090  * asynchronous request and the tricky deadlock (see
2091  * Documentation/filesystems/fuse.rst).
2092  *
2093  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2094  * requests, they should be finished off immediately.  Locked requests will be
2095  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2096  * requests.  It is possible that some request will finish before we can.  This
2097  * is OK, the request will in that case be removed from the list before we touch
2098  * it.
2099  */
2100 void fuse_abort_conn(struct fuse_conn *fc)
2101 {
2102         struct fuse_iqueue *fiq = &fc->iq;
2103
2104         spin_lock(&fc->lock);
2105         if (fc->connected) {
2106                 struct fuse_dev *fud;
2107                 struct fuse_req *req, *next;
2108                 LIST_HEAD(to_end);
2109                 unsigned int i;
2110
2111                 /* Background queuing checks fc->connected under bg_lock */
2112                 spin_lock(&fc->bg_lock);
2113                 fc->connected = 0;
2114                 spin_unlock(&fc->bg_lock);
2115
2116                 fuse_set_initialized(fc);
2117                 list_for_each_entry(fud, &fc->devices, entry) {
2118                         struct fuse_pqueue *fpq = &fud->pq;
2119
2120                         spin_lock(&fpq->lock);
2121                         fpq->connected = 0;
2122                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2123                                 req->out.h.error = -ECONNABORTED;
2124                                 spin_lock(&req->waitq.lock);
2125                                 set_bit(FR_ABORTED, &req->flags);
2126                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2127                                         set_bit(FR_PRIVATE, &req->flags);
2128                                         __fuse_get_request(req);
2129                                         list_move(&req->list, &to_end);
2130                                 }
2131                                 spin_unlock(&req->waitq.lock);
2132                         }
2133                         for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2134                                 list_splice_tail_init(&fpq->processing[i],
2135                                                       &to_end);
2136                         spin_unlock(&fpq->lock);
2137                 }
2138                 spin_lock(&fc->bg_lock);
2139                 fc->blocked = 0;
2140                 fc->max_background = UINT_MAX;
2141                 flush_bg_queue(fc);
2142                 spin_unlock(&fc->bg_lock);
2143
2144                 spin_lock(&fiq->lock);
2145                 fiq->connected = 0;
2146                 list_for_each_entry(req, &fiq->pending, list)
2147                         clear_bit(FR_PENDING, &req->flags);
2148                 list_splice_tail_init(&fiq->pending, &to_end);
2149                 while (forget_pending(fiq))
2150                         kfree(fuse_dequeue_forget(fiq, 1, NULL));
2151                 wake_up_all(&fiq->waitq);
2152                 spin_unlock(&fiq->lock);
2153                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2154                 end_polls(fc);
2155                 wake_up_all(&fc->blocked_waitq);
2156                 spin_unlock(&fc->lock);
2157
2158                 end_requests(&to_end);
2159         } else {
2160                 spin_unlock(&fc->lock);
2161         }
2162 }
2163 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2164
2165 void fuse_wait_aborted(struct fuse_conn *fc)
2166 {
2167         /* matches implicit memory barrier in fuse_drop_waiting() */
2168         smp_mb();
2169         wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2170 }
2171
2172 int fuse_dev_release(struct inode *inode, struct file *file)
2173 {
2174         struct fuse_dev *fud = fuse_get_dev(file);
2175
2176         if (fud) {
2177                 struct fuse_conn *fc = fud->fc;
2178                 struct fuse_pqueue *fpq = &fud->pq;
2179                 LIST_HEAD(to_end);
2180                 unsigned int i;
2181
2182                 spin_lock(&fpq->lock);
2183                 WARN_ON(!list_empty(&fpq->io));
2184                 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2185                         list_splice_init(&fpq->processing[i], &to_end);
2186                 spin_unlock(&fpq->lock);
2187
2188                 end_requests(&to_end);
2189
2190                 /* Are we the last open device? */
2191                 if (atomic_dec_and_test(&fc->dev_count)) {
2192                         WARN_ON(fc->iq.fasync != NULL);
2193                         fuse_abort_conn(fc);
2194                 }
2195                 fuse_dev_free(fud);
2196         }
2197         return 0;
2198 }
2199 EXPORT_SYMBOL_GPL(fuse_dev_release);
2200
2201 static int fuse_dev_fasync(int fd, struct file *file, int on)
2202 {
2203         struct fuse_dev *fud = fuse_get_dev(file);
2204
2205         if (!fud)
2206                 return -EPERM;
2207
2208         /* No locking - fasync_helper does its own locking */
2209         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2210 }
2211
2212 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2213 {
2214         struct fuse_dev *fud;
2215
2216         if (new->private_data)
2217                 return -EINVAL;
2218
2219         fud = fuse_dev_alloc_install(fc);
2220         if (!fud)
2221                 return -ENOMEM;
2222
2223         new->private_data = fud;
2224         atomic_inc(&fc->dev_count);
2225
2226         return 0;
2227 }
2228
2229 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2230                            unsigned long arg)
2231 {
2232         int res;
2233         int oldfd;
2234         struct fuse_dev *fud = NULL;
2235
2236         if (_IOC_TYPE(cmd) != FUSE_DEV_IOC_MAGIC)
2237                 return -ENOTTY;
2238
2239         switch (_IOC_NR(cmd)) {
2240         case _IOC_NR(FUSE_DEV_IOC_CLONE):
2241                 res = -EFAULT;
2242                 if (!get_user(oldfd, (__u32 __user *)arg)) {
2243                         struct file *old = fget(oldfd);
2244
2245                         res = -EINVAL;
2246                         if (old) {
2247                                 /*
2248                                  * Check against file->f_op because CUSE
2249                                  * uses the same ioctl handler.
2250                                  */
2251                                 if (old->f_op == file->f_op &&
2252                                     old->f_cred->user_ns == file->f_cred->user_ns)
2253                                         fud = fuse_get_dev(old);
2254
2255                                 if (fud) {
2256                                         mutex_lock(&fuse_mutex);
2257                                         res = fuse_device_clone(fud->fc, file);
2258                                         mutex_unlock(&fuse_mutex);
2259                                 }
2260                                 fput(old);
2261                         }
2262                 }
2263                 break;
2264         default:
2265                 res = -ENOTTY;
2266                 break;
2267         }
2268         return res;
2269 }
2270
2271 const struct file_operations fuse_dev_operations = {
2272         .owner          = THIS_MODULE,
2273         .open           = fuse_dev_open,
2274         .llseek         = no_llseek,
2275         .read_iter      = fuse_dev_read,
2276         .splice_read    = fuse_dev_splice_read,
2277         .write_iter     = fuse_dev_write,
2278         .splice_write   = fuse_dev_splice_write,
2279         .poll           = fuse_dev_poll,
2280         .release        = fuse_dev_release,
2281         .fasync         = fuse_dev_fasync,
2282         .unlocked_ioctl = fuse_dev_ioctl,
2283         .compat_ioctl   = compat_ptr_ioctl,
2284 };
2285 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2286
2287 static struct miscdevice fuse_miscdevice = {
2288         .minor = FUSE_MINOR,
2289         .name  = "fuse",
2290         .fops = &fuse_dev_operations,
2291 };
2292
2293 int __init fuse_dev_init(void)
2294 {
2295         int err = -ENOMEM;
2296         fuse_req_cachep = kmem_cache_create("fuse_request",
2297                                             sizeof(struct fuse_req),
2298                                             0, 0, NULL);
2299         if (!fuse_req_cachep)
2300                 goto out;
2301
2302         err = misc_register(&fuse_miscdevice);
2303         if (err)
2304                 goto out_cache_clean;
2305
2306         return 0;
2307
2308  out_cache_clean:
2309         kmem_cache_destroy(fuse_req_cachep);
2310  out:
2311         return err;
2312 }
2313
2314 void fuse_dev_cleanup(void)
2315 {
2316         misc_deregister(&fuse_miscdevice);
2317         kmem_cache_destroy(fuse_req_cachep);
2318 }