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/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 matched 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_workingset |
 787                1 << PG_reclaim |
 788                1 << PG_waiters))) {
 789                 dump_page(page, "fuse: trying to steal weird page");
 790                 return 1;
 791         }
 792         return 0;
 793 }
 794
 795 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 796 {
 797         int err;
 798         struct page *oldpage = *pagep;
 799         struct page *newpage;
 800         struct pipe_buffer *buf = cs->pipebufs;
 801
 802         get_page(oldpage);
 803         err = unlock_request(cs->req);
 804         if (err)
 805                 goto out_put_old;
 806
 807         fuse_copy_finish(cs);
 808
 809         err = pipe_buf_confirm(cs->pipe, buf);
 810         if (err)
 811                 goto out_put_old;
 812
 813         BUG_ON(!cs->nr_segs);
 814         cs->currbuf = buf;
 815         cs->len = buf->len;
 816         cs->pipebufs++;
 817         cs->nr_segs--;
 818
 819         if (cs->len != PAGE_SIZE)
 820                 goto out_fallback;
 821
 822         if (!pipe_buf_try_steal(cs->pipe, buf))
 823                 goto out_fallback;
 824
 825         newpage = buf->page;
 826
 827         if (!PageUptodate(newpage))
 828                 SetPageUptodate(newpage);
 829
 830         ClearPageMappedToDisk(newpage);
 831
 832         if (fuse_check_page(newpage) != 0)
 833                 goto out_fallback_unlock;
 834
 835         /*
 836          * This is a new and locked page, it shouldn't be mapped or
 837          * have any special flags on it
 838          */
 839         if (WARN_ON(page_mapped(oldpage)))
 840                 goto out_fallback_unlock;
 841         if (WARN_ON(page_has_private(oldpage)))
 842                 goto out_fallback_unlock;
 843         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 844                 goto out_fallback_unlock;
 845         if (WARN_ON(PageMlocked(oldpage)))
 846                 goto out_fallback_unlock;
 847
 848         replace_page_cache_page(oldpage, newpage);
 849
 850         get_page(newpage);
 851
 852         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 853                 lru_cache_add(newpage);
 854
 855         err = 0;
 856         spin_lock(&cs->req->waitq.lock);
 857         if (test_bit(FR_ABORTED, &cs->req->flags))
 858                 err = -ENOENT;
 859         else
 860                 *pagep = newpage;
 861         spin_unlock(&cs->req->waitq.lock);
 862
 863         if (err) {
 864                 unlock_page(newpage);
 865                 put_page(newpage);
 866                 goto out_put_old;
 867         }
 868
 869         unlock_page(oldpage);
 870         /* Drop ref for ap->pages[] array */
 871         put_page(oldpage);
 872         cs->len = 0;
 873
 874         err = 0;
 875 out_put_old:
 876         /* Drop ref obtained in this function */
 877         put_page(oldpage);
 878         return err;
 879
 880 out_fallback_unlock:
 881         unlock_page(newpage);
 882 out_fallback:
 883         cs->pg = buf->page;
 884         cs->offset = buf->offset;
 885
 886         err = lock_request(cs->req);
 887         if (!err)
 888                 err = 1;
 889
 890         goto out_put_old;
 891 }
 892
 893 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 894                          unsigned offset, unsigned count)
 895 {
 896         struct pipe_buffer *buf;
 897         int err;
 898
 899         if (cs->nr_segs >= cs->pipe->max_usage)
 900                 return -EIO;
 901
 902         get_page(page);
 903         err = unlock_request(cs->req);
 904         if (err) {
 905                 put_page(page);
 906                 return err;
 907         }
 908
 909         fuse_copy_finish(cs);
 910
 911         buf = cs->pipebufs;
 912         buf->page = page;
 913         buf->offset = offset;
 914         buf->len = count;
 915
 916         cs->pipebufs++;
 917         cs->nr_segs++;
 918         cs->len = 0;
 919
 920         return 0;
 921 }
 922
 923 /*
 924  * Copy a page in the request to/from the userspace buffer.  Must be
 925  * done atomically
 926  */
 927 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 928                           unsigned offset, unsigned count, int zeroing)
 929 {
 930         int err;
 931         struct page *page = *pagep;
 932
 933         if (page && zeroing && count < PAGE_SIZE)
 934                 clear_highpage(page);
 935
 936         while (count) {
 937                 if (cs->write && cs->pipebufs && page) {
 938                         return fuse_ref_page(cs, page, offset, count);
 939                 } else if (!cs->len) {
 940                         if (cs->move_pages && page &&
 941                             offset == 0 && count == PAGE_SIZE) {
 942                                 err = fuse_try_move_page(cs, pagep);
 943                                 if (err <= 0)
 944                                         return err;
 945                         } else {
 946                                 err = fuse_copy_fill(cs);
 947                                 if (err)
 948                                         return err;
 949                         }
 950                 }
 951                 if (page) {
 952                         void *mapaddr = kmap_atomic(page);
 953                         void *buf = mapaddr + offset;
 954                         offset += fuse_copy_do(cs, &buf, &count);
 955                         kunmap_atomic(mapaddr);
 956                 } else
 957                         offset += fuse_copy_do(cs, NULL, &count);
 958         }
 959         if (page && !cs->write)
 960                 flush_dcache_page(page);
 961         return 0;
 962 }
 963
 964 /* Copy pages in the request to/from userspace buffer */
 965 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 966                            int zeroing)
 967 {
 968         unsigned i;
 969         struct fuse_req *req = cs->req;
 970         struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
 971
 972
 973         for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
 974                 int err;
 975                 unsigned int offset = ap->descs[i].offset;
 976                 unsigned int count = min(nbytes, ap->descs[i].length);
 977
 978                 err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
 979                 if (err)
 980                         return err;
 981
 982                 nbytes -= count;
 983         }
 984         return 0;
 985 }
 986
 987 /* Copy a single argument in the request to/from userspace buffer */
 988 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
 989 {
 990         while (size) {
 991                 if (!cs->len) {
 992                         int err = fuse_copy_fill(cs);
 993                         if (err)
 994                                 return err;
 995                 }
 996                 fuse_copy_do(cs, &val, &size);
 997         }
 998         return 0;
 999 }
1000
1001 /* Copy request arguments to/from userspace buffer */
1002 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1003                           unsigned argpages, struct fuse_arg *args,
1004                           int zeroing)
1005 {
1006         int err = 0;
1007         unsigned i;
1008
1009         for (i = 0; !err && i < numargs; i++)  {
1010                 struct fuse_arg *arg = &args[i];
1011                 if (i == numargs - 1 && argpages)
1012                         err = fuse_copy_pages(cs, arg->size, zeroing);
1013                 else
1014                         err = fuse_copy_one(cs, arg->value, arg->size);
1015         }
1016         return err;
1017 }
1018
1019 static int forget_pending(struct fuse_iqueue *fiq)
1020 {
1021         return fiq->forget_list_head.next != NULL;
1022 }
1023
1024 static int request_pending(struct fuse_iqueue *fiq)
1025 {
1026         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1027                 forget_pending(fiq);
1028 }
1029
1030 /*
1031  * Transfer an interrupt request to userspace
1032  *
1033  * Unlike other requests this is assembled on demand, without a need
1034  * to allocate a separate fuse_req structure.
1035  *
1036  * Called with fiq->lock held, releases it
1037  */
1038 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1039                                struct fuse_copy_state *cs,
1040                                size_t nbytes, struct fuse_req *req)
1041 __releases(fiq->lock)
1042 {
1043         struct fuse_in_header ih;
1044         struct fuse_interrupt_in arg;
1045         unsigned reqsize = sizeof(ih) + sizeof(arg);
1046         int err;
1047
1048         list_del_init(&req->intr_entry);
1049         memset(&ih, 0, sizeof(ih));
1050         memset(&arg, 0, sizeof(arg));
1051         ih.len = reqsize;
1052         ih.opcode = FUSE_INTERRUPT;
1053         ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1054         arg.unique = req->in.h.unique;
1055
1056         spin_unlock(&fiq->lock);
1057         if (nbytes < reqsize)
1058                 return -EINVAL;
1059
1060         err = fuse_copy_one(cs, &ih, sizeof(ih));
1061         if (!err)
1062                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1063         fuse_copy_finish(cs);
1064
1065         return err ? err : reqsize;
1066 }
1067
1068 struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1069                                              unsigned int max,
1070                                              unsigned int *countp)
1071 {
1072         struct fuse_forget_link *head = fiq->forget_list_head.next;
1073         struct fuse_forget_link **newhead = &head;
1074         unsigned count;
1075
1076         for (count = 0; *newhead != NULL && count < max; count++)
1077                 newhead = &(*newhead)->next;
1078
1079         fiq->forget_list_head.next = *newhead;
1080         *newhead = NULL;
1081         if (fiq->forget_list_head.next == NULL)
1082                 fiq->forget_list_tail = &fiq->forget_list_head;
1083
1084         if (countp != NULL)
1085                 *countp = count;
1086
1087         return head;
1088 }
1089 EXPORT_SYMBOL(fuse_dequeue_forget);
1090
1091 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1092                                    struct fuse_copy_state *cs,
1093                                    size_t nbytes)
1094 __releases(fiq->lock)
1095 {
1096         int err;
1097         struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1098         struct fuse_forget_in arg = {
1099                 .nlookup = forget->forget_one.nlookup,
1100         };
1101         struct fuse_in_header ih = {
1102                 .opcode = FUSE_FORGET,
1103                 .nodeid = forget->forget_one.nodeid,
1104                 .unique = fuse_get_unique(fiq),
1105                 .len = sizeof(ih) + sizeof(arg),
1106         };
1107
1108         spin_unlock(&fiq->lock);
1109         kfree(forget);
1110         if (nbytes < ih.len)
1111                 return -EINVAL;
1112
1113         err = fuse_copy_one(cs, &ih, sizeof(ih));
1114         if (!err)
1115                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1116         fuse_copy_finish(cs);
1117
1118         if (err)
1119                 return err;
1120
1121         return ih.len;
1122 }
1123
1124 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1125                                    struct fuse_copy_state *cs, size_t nbytes)
1126 __releases(fiq->lock)
1127 {
1128         int err;
1129         unsigned max_forgets;
1130         unsigned count;
1131         struct fuse_forget_link *head;
1132         struct fuse_batch_forget_in arg = { .count = 0 };
1133         struct fuse_in_header ih = {
1134                 .opcode = FUSE_BATCH_FORGET,
1135                 .unique = fuse_get_unique(fiq),
1136                 .len = sizeof(ih) + sizeof(arg),
1137         };
1138
1139         if (nbytes < ih.len) {
1140                 spin_unlock(&fiq->lock);
1141                 return -EINVAL;
1142         }
1143
1144         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1145         head = fuse_dequeue_forget(fiq, max_forgets, &count);
1146         spin_unlock(&fiq->lock);
1147
1148         arg.count = count;
1149         ih.len += count * sizeof(struct fuse_forget_one);
1150         err = fuse_copy_one(cs, &ih, sizeof(ih));
1151         if (!err)
1152                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1153
1154         while (head) {
1155                 struct fuse_forget_link *forget = head;
1156
1157                 if (!err) {
1158                         err = fuse_copy_one(cs, &forget->forget_one,
1159                                             sizeof(forget->forget_one));
1160                 }
1161                 head = forget->next;
1162                 kfree(forget);
1163         }
1164
1165         fuse_copy_finish(cs);
1166
1167         if (err)
1168                 return err;
1169
1170         return ih.len;
1171 }
1172
1173 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1174                             struct fuse_copy_state *cs,
1175                             size_t nbytes)
1176 __releases(fiq->lock)
1177 {
1178         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1179                 return fuse_read_single_forget(fiq, cs, nbytes);
1180         else
1181                 return fuse_read_batch_forget(fiq, cs, nbytes);
1182 }
1183
1184 /*
1185  * Read a single request into the userspace filesystem's buffer.  This
1186  * function waits until a request is available, then removes it from
1187  * the pending list and copies request data to userspace buffer.  If
1188  * no reply is needed (FORGET) or request has been aborted or there
1189  * was an error during the copying then it's finished by calling
1190  * fuse_request_end().  Otherwise add it to the processing list, and set
1191  * the 'sent' flag.
1192  */
1193 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1194                                 struct fuse_copy_state *cs, size_t nbytes)
1195 {
1196         ssize_t err;
1197         struct fuse_conn *fc = fud->fc;
1198         struct fuse_iqueue *fiq = &fc->iq;
1199         struct fuse_pqueue *fpq = &fud->pq;
1200         struct fuse_req *req;
1201         struct fuse_args *args;
1202         unsigned reqsize;
1203         unsigned int hash;
1204
1205         /*
1206          * Require sane minimum read buffer - that has capacity for fixed part
1207          * of any request header + negotiated max_write room for data.
1208          *
1209          * Historically libfuse reserves 4K for fixed header room, but e.g.
1210          * GlusterFS reserves only 80 bytes
1211          *
1212          *      = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1213          *
1214          * which is the absolute minimum any sane filesystem should be using
1215          * for header room.
1216          */
1217         if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1218                            sizeof(struct fuse_in_header) +
1219                            sizeof(struct fuse_write_in) +
1220                            fc->max_write))
1221                 return -EINVAL;
1222
1223  restart:
1224         for (;;) {
1225                 spin_lock(&fiq->lock);
1226                 if (!fiq->connected || request_pending(fiq))
1227                         break;
1228                 spin_unlock(&fiq->lock);
1229
1230                 if (file->f_flags & O_NONBLOCK)
1231                         return -EAGAIN;
1232                 err = wait_event_interruptible_exclusive(fiq->waitq,
1233                                 !fiq->connected || request_pending(fiq));
1234                 if (err)
1235                         return err;
1236         }
1237
1238         if (!fiq->connected) {
1239                 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1240                 goto err_unlock;
1241         }
1242
1243         if (!list_empty(&fiq->interrupts)) {
1244                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1245                                  intr_entry);
1246                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1247         }
1248
1249         if (forget_pending(fiq)) {
1250                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1251                         return fuse_read_forget(fc, fiq, cs, nbytes);
1252
1253                 if (fiq->forget_batch <= -8)
1254                         fiq->forget_batch = 16;
1255         }
1256
1257         req = list_entry(fiq->pending.next, struct fuse_req, list);
1258         clear_bit(FR_PENDING, &req->flags);
1259         list_del_init(&req->list);
1260         spin_unlock(&fiq->lock);
1261
1262         args = req->args;
1263         reqsize = req->in.h.len;
1264
1265         /* If request is too large, reply with an error and restart the read */
1266         if (nbytes < reqsize) {
1267                 req->out.h.error = -EIO;
1268                 /* SETXATTR is special, since it may contain too large data */
1269                 if (args->opcode == FUSE_SETXATTR)
1270                         req->out.h.error = -E2BIG;
1271                 fuse_request_end(req);
1272                 goto restart;
1273         }
1274         spin_lock(&fpq->lock);
1275         /*
1276          *  Must not put request on fpq->io queue after having been shut down by
1277          *  fuse_abort_conn()
1278          */
1279         if (!fpq->connected) {
1280                 req->out.h.error = err = -ECONNABORTED;
1281                 goto out_end;
1282
1283         }
1284         list_add(&req->list, &fpq->io);
1285         spin_unlock(&fpq->lock);
1286         cs->req = req;
1287         err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1288         if (!err)
1289                 err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1290                                      (struct fuse_arg *) args->in_args, 0);
1291         fuse_copy_finish(cs);
1292         spin_lock(&fpq->lock);
1293         clear_bit(FR_LOCKED, &req->flags);
1294         if (!fpq->connected) {
1295                 err = fc->aborted ? -ECONNABORTED : -ENODEV;
1296                 goto out_end;
1297         }
1298         if (err) {
1299                 req->out.h.error = -EIO;
1300                 goto out_end;
1301         }
1302         if (!test_bit(FR_ISREPLY, &req->flags)) {
1303                 err = reqsize;
1304                 goto out_end;
1305         }
1306         hash = fuse_req_hash(req->in.h.unique);
1307         list_move_tail(&req->list, &fpq->processing[hash]);
1308         __fuse_get_request(req);
1309         set_bit(FR_SENT, &req->flags);
1310         spin_unlock(&fpq->lock);
1311         /* matches barrier in request_wait_answer() */
1312         smp_mb__after_atomic();
1313         if (test_bit(FR_INTERRUPTED, &req->flags))
1314                 queue_interrupt(req);
1315         fuse_put_request(req);
1316
1317         return reqsize;
1318
1319 out_end:
1320         if (!test_bit(FR_PRIVATE, &req->flags))
1321                 list_del_init(&req->list);
1322         spin_unlock(&fpq->lock);
1323         fuse_request_end(req);
1324         return err;
1325
1326  err_unlock:
1327         spin_unlock(&fiq->lock);
1328         return err;
1329 }
1330
1331 static int fuse_dev_open(struct inode *inode, struct file *file)
1332 {
1333         /*
1334          * The fuse device's file's private_data is used to hold
1335          * the fuse_conn(ection) when it is mounted, and is used to
1336          * keep track of whether the file has been mounted already.
1337          */
1338         file->private_data = NULL;
1339         return 0;
1340 }
1341
1342 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1343 {
1344         struct fuse_copy_state cs;
1345         struct file *file = iocb->ki_filp;
1346         struct fuse_dev *fud = fuse_get_dev(file);
1347
1348         if (!fud)
1349                 return -EPERM;
1350
1351         if (!iter_is_iovec(to))
1352                 return -EINVAL;
1353
1354         fuse_copy_init(&cs, 1, to);
1355
1356         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1357 }
1358
1359 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1360                                     struct pipe_inode_info *pipe,
1361                                     size_t len, unsigned int flags)
1362 {
1363         int total, ret;
1364         int page_nr = 0;
1365         struct pipe_buffer *bufs;
1366         struct fuse_copy_state cs;
1367         struct fuse_dev *fud = fuse_get_dev(in);
1368
1369         if (!fud)
1370                 return -EPERM;
1371
1372         bufs = kvmalloc_array(pipe->max_usage, sizeof(struct pipe_buffer),
1373                               GFP_KERNEL);
1374         if (!bufs)
1375                 return -ENOMEM;
1376
1377         fuse_copy_init(&cs, 1, NULL);
1378         cs.pipebufs = bufs;
1379         cs.pipe = pipe;
1380         ret = fuse_dev_do_read(fud, in, &cs, len);
1381         if (ret < 0)
1382                 goto out;
1383
1384         if (pipe_occupancy(pipe->head, pipe->tail) + cs.nr_segs > pipe->max_usage) {
1385                 ret = -EIO;
1386                 goto out;
1387         }
1388
1389         for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1390                 /*
1391                  * Need to be careful about this.  Having buf->ops in module
1392                  * code can Oops if the buffer persists after module unload.
1393                  */
1394                 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1395                 bufs[page_nr].flags = 0;
1396                 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1397                 if (unlikely(ret < 0))
1398                         break;
1399         }
1400         if (total)
1401                 ret = total;
1402 out:
1403         for (; page_nr < cs.nr_segs; page_nr++)
1404                 put_page(bufs[page_nr].page);
1405
1406         kvfree(bufs);
1407         return ret;
1408 }
1409
1410 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1411                             struct fuse_copy_state *cs)
1412 {
1413         struct fuse_notify_poll_wakeup_out outarg;
1414         int err = -EINVAL;
1415
1416         if (size != sizeof(outarg))
1417                 goto err;
1418
1419         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1420         if (err)
1421                 goto err;
1422
1423         fuse_copy_finish(cs);
1424         return fuse_notify_poll_wakeup(fc, &outarg);
1425
1426 err:
1427         fuse_copy_finish(cs);
1428         return err;
1429 }
1430
1431 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1432                                    struct fuse_copy_state *cs)
1433 {
1434         struct fuse_notify_inval_inode_out outarg;
1435         int err = -EINVAL;
1436
1437         if (size != sizeof(outarg))
1438                 goto err;
1439
1440         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1441         if (err)
1442                 goto err;
1443         fuse_copy_finish(cs);
1444
1445         down_read(&fc->killsb);
1446         err = fuse_reverse_inval_inode(fc, outarg.ino,
1447                                        outarg.off, outarg.len);
1448         up_read(&fc->killsb);
1449         return err;
1450
1451 err:
1452         fuse_copy_finish(cs);
1453         return err;
1454 }
1455
1456 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1457                                    struct fuse_copy_state *cs)
1458 {
1459         struct fuse_notify_inval_entry_out outarg;
1460         int err = -ENOMEM;
1461         char *buf;
1462         struct qstr name;
1463
1464         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1465         if (!buf)
1466                 goto err;
1467
1468         err = -EINVAL;
1469         if (size < sizeof(outarg))
1470                 goto err;
1471
1472         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1473         if (err)
1474                 goto err;
1475
1476         err = -ENAMETOOLONG;
1477         if (outarg.namelen > FUSE_NAME_MAX)
1478                 goto err;
1479
1480         err = -EINVAL;
1481         if (size != sizeof(outarg) + outarg.namelen + 1)
1482                 goto err;
1483
1484         name.name = buf;
1485         name.len = outarg.namelen;
1486         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1487         if (err)
1488                 goto err;
1489         fuse_copy_finish(cs);
1490         buf[outarg.namelen] = 0;
1491
1492         down_read(&fc->killsb);
1493         err = fuse_reverse_inval_entry(fc, outarg.parent, 0, &name);
1494         up_read(&fc->killsb);
1495         kfree(buf);
1496         return err;
1497
1498 err:
1499         kfree(buf);
1500         fuse_copy_finish(cs);
1501         return err;
1502 }
1503
1504 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1505                               struct fuse_copy_state *cs)
1506 {
1507         struct fuse_notify_delete_out outarg;
1508         int err = -ENOMEM;
1509         char *buf;
1510         struct qstr name;
1511
1512         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1513         if (!buf)
1514                 goto err;
1515
1516         err = -EINVAL;
1517         if (size < sizeof(outarg))
1518                 goto err;
1519
1520         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1521         if (err)
1522                 goto err;
1523
1524         err = -ENAMETOOLONG;
1525         if (outarg.namelen > FUSE_NAME_MAX)
1526                 goto err;
1527
1528         err = -EINVAL;
1529         if (size != sizeof(outarg) + outarg.namelen + 1)
1530                 goto err;
1531
1532         name.name = buf;
1533         name.len = outarg.namelen;
1534         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1535         if (err)
1536                 goto err;
1537         fuse_copy_finish(cs);
1538         buf[outarg.namelen] = 0;
1539
1540         down_read(&fc->killsb);
1541         err = fuse_reverse_inval_entry(fc, outarg.parent, outarg.child, &name);
1542         up_read(&fc->killsb);
1543         kfree(buf);
1544         return err;
1545
1546 err:
1547         kfree(buf);
1548         fuse_copy_finish(cs);
1549         return err;
1550 }
1551
1552 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1553                              struct fuse_copy_state *cs)
1554 {
1555         struct fuse_notify_store_out outarg;
1556         struct inode *inode;
1557         struct address_space *mapping;
1558         u64 nodeid;
1559         int err;
1560         pgoff_t index;
1561         unsigned int offset;
1562         unsigned int num;
1563         loff_t file_size;
1564         loff_t end;
1565
1566         err = -EINVAL;
1567         if (size < sizeof(outarg))
1568                 goto out_finish;
1569
1570         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1571         if (err)
1572                 goto out_finish;
1573
1574         err = -EINVAL;
1575         if (size - sizeof(outarg) != outarg.size)
1576                 goto out_finish;
1577
1578         nodeid = outarg.nodeid;
1579
1580         down_read(&fc->killsb);
1581
1582         err = -ENOENT;
1583         inode = fuse_ilookup(fc, nodeid,  NULL);
1584         if (!inode)
1585                 goto out_up_killsb;
1586
1587         mapping = inode->i_mapping;
1588         index = outarg.offset >> PAGE_SHIFT;
1589         offset = outarg.offset & ~PAGE_MASK;
1590         file_size = i_size_read(inode);
1591         end = outarg.offset + outarg.size;
1592         if (end > file_size) {
1593                 file_size = end;
1594                 fuse_write_update_size(inode, file_size);
1595         }
1596
1597         num = outarg.size;
1598         while (num) {
1599                 struct page *page;
1600                 unsigned int this_num;
1601
1602                 err = -ENOMEM;
1603                 page = find_or_create_page(mapping, index,
1604                                            mapping_gfp_mask(mapping));
1605                 if (!page)
1606                         goto out_iput;
1607
1608                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1609                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1610                 if (!err && offset == 0 &&
1611                     (this_num == PAGE_SIZE || file_size == end))
1612                         SetPageUptodate(page);
1613                 unlock_page(page);
1614                 put_page(page);
1615
1616                 if (err)
1617                         goto out_iput;
1618
1619                 num -= this_num;
1620                 offset = 0;
1621                 index++;
1622         }
1623
1624         err = 0;
1625
1626 out_iput:
1627         iput(inode);
1628 out_up_killsb:
1629         up_read(&fc->killsb);
1630 out_finish:
1631         fuse_copy_finish(cs);
1632         return err;
1633 }
1634
1635 struct fuse_retrieve_args {
1636         struct fuse_args_pages ap;
1637         struct fuse_notify_retrieve_in inarg;
1638 };
1639
1640 static void fuse_retrieve_end(struct fuse_mount *fm, struct fuse_args *args,
1641                               int error)
1642 {
1643         struct fuse_retrieve_args *ra =
1644                 container_of(args, typeof(*ra), ap.args);
1645
1646         release_pages(ra->ap.pages, ra->ap.num_pages);
1647         kfree(ra);
1648 }
1649
1650 static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
1651                          struct fuse_notify_retrieve_out *outarg)
1652 {
1653         int err;
1654         struct address_space *mapping = inode->i_mapping;
1655         pgoff_t index;
1656         loff_t file_size;
1657         unsigned int num;
1658         unsigned int offset;
1659         size_t total_len = 0;
1660         unsigned int num_pages;
1661         struct fuse_conn *fc = fm->fc;
1662         struct fuse_retrieve_args *ra;
1663         size_t args_size = sizeof(*ra);
1664         struct fuse_args_pages *ap;
1665         struct fuse_args *args;
1666
1667         offset = outarg->offset & ~PAGE_MASK;
1668         file_size = i_size_read(inode);
1669
1670         num = min(outarg->size, fc->max_write);
1671         if (outarg->offset > file_size)
1672                 num = 0;
1673         else if (outarg->offset + num > file_size)
1674                 num = file_size - outarg->offset;
1675
1676         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1677         num_pages = min(num_pages, fc->max_pages);
1678
1679         args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1680
1681         ra = kzalloc(args_size, GFP_KERNEL);
1682         if (!ra)
1683                 return -ENOMEM;
1684
1685         ap = &ra->ap;
1686         ap->pages = (void *) (ra + 1);
1687         ap->descs = (void *) (ap->pages + num_pages);
1688
1689         args = &ap->args;
1690         args->nodeid = outarg->nodeid;
1691         args->opcode = FUSE_NOTIFY_REPLY;
1692         args->in_numargs = 2;
1693         args->in_pages = true;
1694         args->end = fuse_retrieve_end;
1695
1696         index = outarg->offset >> PAGE_SHIFT;
1697
1698         while (num && ap->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                 ap->pages[ap->num_pages] = page;
1708                 ap->descs[ap->num_pages].offset = offset;
1709                 ap->descs[ap->num_pages].length = this_num;
1710                 ap->num_pages++;
1711
1712                 offset = 0;
1713                 num -= this_num;
1714                 total_len += this_num;
1715                 index++;
1716         }
1717         ra->inarg.offset = outarg->offset;
1718         ra->inarg.size = total_len;
1719         args->in_args[0].size = sizeof(ra->inarg);
1720         args->in_args[0].value = &ra->inarg;
1721         args->in_args[1].size = total_len;
1722
1723         err = fuse_simple_notify_reply(fm, args, outarg->notify_unique);
1724         if (err)
1725                 fuse_retrieve_end(fm, args, err);
1726
1727         return err;
1728 }
1729
1730 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1731                                 struct fuse_copy_state *cs)
1732 {
1733         struct fuse_notify_retrieve_out outarg;
1734         struct fuse_mount *fm;
1735         struct inode *inode;
1736         u64 nodeid;
1737         int err;
1738
1739         err = -EINVAL;
1740         if (size != sizeof(outarg))
1741                 goto copy_finish;
1742
1743         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1744         if (err)
1745                 goto copy_finish;
1746
1747         fuse_copy_finish(cs);
1748
1749         down_read(&fc->killsb);
1750         err = -ENOENT;
1751         nodeid = outarg.nodeid;
1752
1753         inode = fuse_ilookup(fc, nodeid, &fm);
1754         if (inode) {
1755                 err = fuse_retrieve(fm, inode, &outarg);
1756                 iput(inode);
1757         }
1758         up_read(&fc->killsb);
1759
1760         return err;
1761
1762 copy_finish:
1763         fuse_copy_finish(cs);
1764         return err;
1765 }
1766
1767 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1768                        unsigned int size, struct fuse_copy_state *cs)
1769 {
1770         /* Don't try to move pages (yet) */
1771         cs->move_pages = 0;
1772
1773         switch (code) {
1774         case FUSE_NOTIFY_POLL:
1775                 return fuse_notify_poll(fc, size, cs);
1776
1777         case FUSE_NOTIFY_INVAL_INODE:
1778                 return fuse_notify_inval_inode(fc, size, cs);
1779
1780         case FUSE_NOTIFY_INVAL_ENTRY:
1781                 return fuse_notify_inval_entry(fc, size, cs);
1782
1783         case FUSE_NOTIFY_STORE:
1784                 return fuse_notify_store(fc, size, cs);
1785
1786         case FUSE_NOTIFY_RETRIEVE:
1787                 return fuse_notify_retrieve(fc, size, cs);
1788
1789         case FUSE_NOTIFY_DELETE:
1790                 return fuse_notify_delete(fc, size, cs);
1791
1792         default:
1793                 fuse_copy_finish(cs);
1794                 return -EINVAL;
1795         }
1796 }
1797
1798 /* Look up request on processing list by unique ID */
1799 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1800 {
1801         unsigned int hash = fuse_req_hash(unique);
1802         struct fuse_req *req;
1803
1804         list_for_each_entry(req, &fpq->processing[hash], list) {
1805                 if (req->in.h.unique == unique)
1806                         return req;
1807         }
1808         return NULL;
1809 }
1810
1811 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1812                          unsigned nbytes)
1813 {
1814         unsigned reqsize = sizeof(struct fuse_out_header);
1815
1816         reqsize += fuse_len_args(args->out_numargs, args->out_args);
1817
1818         if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1819                 return -EINVAL;
1820         else if (reqsize > nbytes) {
1821                 struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1822                 unsigned diffsize = reqsize - nbytes;
1823
1824                 if (diffsize > lastarg->size)
1825                         return -EINVAL;
1826                 lastarg->size -= diffsize;
1827         }
1828         return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1829                               args->out_args, args->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 fuse_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         err = -EINVAL;
1849         if (nbytes < sizeof(struct fuse_out_header))
1850                 goto out;
1851
1852         err = fuse_copy_one(cs, &oh, sizeof(oh));
1853         if (err)
1854                 goto copy_finish;
1855
1856         err = -EINVAL;
1857         if (oh.len != nbytes)
1858                 goto copy_finish;
1859
1860         /*
1861          * Zero oh.unique indicates unsolicited notification message
1862          * and error contains notification code.
1863          */
1864         if (!oh.unique) {
1865                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1866                 goto out;
1867         }
1868
1869         err = -EINVAL;
1870         if (oh.error <= -512 || oh.error > 0)
1871                 goto copy_finish;
1872
1873         spin_lock(&fpq->lock);
1874         req = NULL;
1875         if (fpq->connected)
1876                 req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1877
1878         err = -ENOENT;
1879         if (!req) {
1880                 spin_unlock(&fpq->lock);
1881                 goto copy_finish;
1882         }
1883
1884         /* Is it an interrupt reply ID? */
1885         if (oh.unique & FUSE_INT_REQ_BIT) {
1886                 __fuse_get_request(req);
1887                 spin_unlock(&fpq->lock);
1888
1889                 err = 0;
1890                 if (nbytes != sizeof(struct fuse_out_header))
1891                         err = -EINVAL;
1892                 else if (oh.error == -ENOSYS)
1893                         fc->no_interrupt = 1;
1894                 else if (oh.error == -EAGAIN)
1895                         err = queue_interrupt(req);
1896
1897                 fuse_put_request(req);
1898
1899                 goto copy_finish;
1900         }
1901
1902         clear_bit(FR_SENT, &req->flags);
1903         list_move(&req->list, &fpq->io);
1904         req->out.h = oh;
1905         set_bit(FR_LOCKED, &req->flags);
1906         spin_unlock(&fpq->lock);
1907         cs->req = req;
1908         if (!req->args->page_replace)
1909                 cs->move_pages = 0;
1910
1911         if (oh.error)
1912                 err = nbytes != sizeof(oh) ? -EINVAL : 0;
1913         else
1914                 err = copy_out_args(cs, req->args, nbytes);
1915         fuse_copy_finish(cs);
1916
1917         spin_lock(&fpq->lock);
1918         clear_bit(FR_LOCKED, &req->flags);
1919         if (!fpq->connected)
1920                 err = -ENOENT;
1921         else if (err)
1922                 req->out.h.error = -EIO;
1923         if (!test_bit(FR_PRIVATE, &req->flags))
1924                 list_del_init(&req->list);
1925         spin_unlock(&fpq->lock);
1926
1927         fuse_request_end(req);
1928 out:
1929         return err ? err : nbytes;
1930
1931 copy_finish:
1932         fuse_copy_finish(cs);
1933         goto out;
1934 }
1935
1936 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1937 {
1938         struct fuse_copy_state cs;
1939         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1940
1941         if (!fud)
1942                 return -EPERM;
1943
1944         if (!iter_is_iovec(from))
1945                 return -EINVAL;
1946
1947         fuse_copy_init(&cs, 0, from);
1948
1949         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1950 }
1951
1952 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1953                                      struct file *out, loff_t *ppos,
1954                                      size_t len, unsigned int flags)
1955 {
1956         unsigned int head, tail, mask, count;
1957         unsigned nbuf;
1958         unsigned idx;
1959         struct pipe_buffer *bufs;
1960         struct fuse_copy_state cs;
1961         struct fuse_dev *fud;
1962         size_t rem;
1963         ssize_t ret;
1964
1965         fud = fuse_get_dev(out);
1966         if (!fud)
1967                 return -EPERM;
1968
1969         pipe_lock(pipe);
1970
1971         head = pipe->head;
1972         tail = pipe->tail;
1973         mask = pipe->ring_size - 1;
1974         count = head - tail;
1975
1976         bufs = kvmalloc_array(count, sizeof(struct pipe_buffer), GFP_KERNEL);
1977         if (!bufs) {
1978                 pipe_unlock(pipe);
1979                 return -ENOMEM;
1980         }
1981
1982         nbuf = 0;
1983         rem = 0;
1984         for (idx = tail; idx != head && rem < len; idx++)
1985                 rem += pipe->bufs[idx & mask].len;
1986
1987         ret = -EINVAL;
1988         if (rem < len)
1989                 goto out_free;
1990
1991         rem = len;
1992         while (rem) {
1993                 struct pipe_buffer *ibuf;
1994                 struct pipe_buffer *obuf;
1995
1996                 if (WARN_ON(nbuf >= count || tail == head))
1997                         goto out_free;
1998
1999                 ibuf = &pipe->bufs[tail & mask];
2000                 obuf = &bufs[nbuf];
2001
2002                 if (rem >= ibuf->len) {
2003                         *obuf = *ibuf;
2004                         ibuf->ops = NULL;
2005                         tail++;
2006                         pipe->tail = tail;
2007                 } else {
2008                         if (!pipe_buf_get(pipe, ibuf))
2009                                 goto out_free;
2010
2011                         *obuf = *ibuf;
2012                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2013                         obuf->len = rem;
2014                         ibuf->offset += obuf->len;
2015                         ibuf->len -= obuf->len;
2016                 }
2017                 nbuf++;
2018                 rem -= obuf->len;
2019         }
2020         pipe_unlock(pipe);
2021
2022         fuse_copy_init(&cs, 0, NULL);
2023         cs.pipebufs = bufs;
2024         cs.nr_segs = nbuf;
2025         cs.pipe = pipe;
2026
2027         if (flags & SPLICE_F_MOVE)
2028                 cs.move_pages = 1;
2029
2030         ret = fuse_dev_do_write(fud, &cs, len);
2031
2032         pipe_lock(pipe);
2033 out_free:
2034         for (idx = 0; idx < nbuf; idx++)
2035                 pipe_buf_release(pipe, &bufs[idx]);
2036         pipe_unlock(pipe);
2037
2038         kvfree(bufs);
2039         return ret;
2040 }
2041
2042 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2043 {
2044         __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2045         struct fuse_iqueue *fiq;
2046         struct fuse_dev *fud = fuse_get_dev(file);
2047
2048         if (!fud)
2049                 return EPOLLERR;
2050
2051         fiq = &fud->fc->iq;
2052         poll_wait(file, &fiq->waitq, wait);
2053
2054         spin_lock(&fiq->lock);
2055         if (!fiq->connected)
2056                 mask = EPOLLERR;
2057         else if (request_pending(fiq))
2058                 mask |= EPOLLIN | EPOLLRDNORM;
2059         spin_unlock(&fiq->lock);
2060
2061         return mask;
2062 }
2063
2064 /* Abort all requests on the given list (pending or processing) */
2065 static void end_requests(struct list_head *head)
2066 {
2067         while (!list_empty(head)) {
2068                 struct fuse_req *req;
2069                 req = list_entry(head->next, struct fuse_req, list);
2070                 req->out.h.error = -ECONNABORTED;
2071                 clear_bit(FR_SENT, &req->flags);
2072                 list_del_init(&req->list);
2073                 fuse_request_end(req);
2074         }
2075 }
2076
2077 static void end_polls(struct fuse_conn *fc)
2078 {
2079         struct rb_node *p;
2080
2081         p = rb_first(&fc->polled_files);
2082
2083         while (p) {
2084                 struct fuse_file *ff;
2085                 ff = rb_entry(p, struct fuse_file, polled_node);
2086                 wake_up_interruptible_all(&ff->poll_wait);
2087
2088                 p = rb_next(p);
2089         }
2090 }
2091
2092 /*
2093  * Abort all requests.
2094  *
2095  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2096  * filesystem.
2097  *
2098  * The same effect is usually achievable through killing the filesystem daemon
2099  * and all users of the filesystem.  The exception is the combination of an
2100  * asynchronous request and the tricky deadlock (see
2101  * Documentation/filesystems/fuse.rst).
2102  *
2103  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2104  * requests, they should be finished off immediately.  Locked requests will be
2105  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2106  * requests.  It is possible that some request will finish before we can.  This
2107  * is OK, the request will in that case be removed from the list before we touch
2108  * it.
2109  */
2110 void fuse_abort_conn(struct fuse_conn *fc)
2111 {
2112         struct fuse_iqueue *fiq = &fc->iq;
2113
2114         spin_lock(&fc->lock);
2115         if (fc->connected) {
2116                 struct fuse_dev *fud;
2117                 struct fuse_req *req, *next;
2118                 LIST_HEAD(to_end);
2119                 unsigned int i;
2120
2121                 /* Background queuing checks fc->connected under bg_lock */
2122                 spin_lock(&fc->bg_lock);
2123                 fc->connected = 0;
2124                 spin_unlock(&fc->bg_lock);
2125
2126                 fuse_set_initialized(fc);
2127                 list_for_each_entry(fud, &fc->devices, entry) {
2128                         struct fuse_pqueue *fpq = &fud->pq;
2129
2130                         spin_lock(&fpq->lock);
2131                         fpq->connected = 0;
2132                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2133                                 req->out.h.error = -ECONNABORTED;
2134                                 spin_lock(&req->waitq.lock);
2135                                 set_bit(FR_ABORTED, &req->flags);
2136                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2137                                         set_bit(FR_PRIVATE, &req->flags);
2138                                         __fuse_get_request(req);
2139                                         list_move(&req->list, &to_end);
2140                                 }
2141                                 spin_unlock(&req->waitq.lock);
2142                         }
2143                         for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2144                                 list_splice_tail_init(&fpq->processing[i],
2145                                                       &to_end);
2146                         spin_unlock(&fpq->lock);
2147                 }
2148                 spin_lock(&fc->bg_lock);
2149                 fc->blocked = 0;
2150                 fc->max_background = UINT_MAX;
2151                 flush_bg_queue(fc);
2152                 spin_unlock(&fc->bg_lock);
2153
2154                 spin_lock(&fiq->lock);
2155                 fiq->connected = 0;
2156                 list_for_each_entry(req, &fiq->pending, list)
2157                         clear_bit(FR_PENDING, &req->flags);
2158                 list_splice_tail_init(&fiq->pending, &to_end);
2159                 while (forget_pending(fiq))
2160                         kfree(fuse_dequeue_forget(fiq, 1, NULL));
2161                 wake_up_all(&fiq->waitq);
2162                 spin_unlock(&fiq->lock);
2163                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2164                 end_polls(fc);
2165                 wake_up_all(&fc->blocked_waitq);
2166                 spin_unlock(&fc->lock);
2167
2168                 end_requests(&to_end);
2169         } else {
2170                 spin_unlock(&fc->lock);
2171         }
2172 }
2173 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2174
2175 void fuse_wait_aborted(struct fuse_conn *fc)
2176 {
2177         /* matches implicit memory barrier in fuse_drop_waiting() */
2178         smp_mb();
2179         wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2180 }
2181
2182 int fuse_dev_release(struct inode *inode, struct file *file)
2183 {
2184         struct fuse_dev *fud = fuse_get_dev(file);
2185
2186         if (fud) {
2187                 struct fuse_conn *fc = fud->fc;
2188                 struct fuse_pqueue *fpq = &fud->pq;
2189                 LIST_HEAD(to_end);
2190                 unsigned int i;
2191
2192                 spin_lock(&fpq->lock);
2193                 WARN_ON(!list_empty(&fpq->io));
2194                 for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2195                         list_splice_init(&fpq->processing[i], &to_end);
2196                 spin_unlock(&fpq->lock);
2197
2198                 end_requests(&to_end);
2199
2200                 /* Are we the last open device? */
2201                 if (atomic_dec_and_test(&fc->dev_count)) {
2202                         WARN_ON(fc->iq.fasync != NULL);
2203                         fuse_abort_conn(fc);
2204                 }
2205                 fuse_dev_free(fud);
2206         }
2207         return 0;
2208 }
2209 EXPORT_SYMBOL_GPL(fuse_dev_release);
2210
2211 static int fuse_dev_fasync(int fd, struct file *file, int on)
2212 {
2213         struct fuse_dev *fud = fuse_get_dev(file);
2214
2215         if (!fud)
2216                 return -EPERM;
2217
2218         /* No locking - fasync_helper does its own locking */
2219         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2220 }
2221
2222 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2223 {
2224         struct fuse_dev *fud;
2225
2226         if (new->private_data)
2227                 return -EINVAL;
2228
2229         fud = fuse_dev_alloc_install(fc);
2230         if (!fud)
2231                 return -ENOMEM;
2232
2233         new->private_data = fud;
2234         atomic_inc(&fc->dev_count);
2235
2236         return 0;
2237 }
2238
2239 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2240                            unsigned long arg)
2241 {
2242         int res;
2243         int oldfd;
2244         struct fuse_dev *fud = NULL;
2245
2246         switch (cmd) {
2247         case FUSE_DEV_IOC_CLONE:
2248                 res = -EFAULT;
2249                 if (!get_user(oldfd, (__u32 __user *)arg)) {
2250                         struct file *old = fget(oldfd);
2251
2252                         res = -EINVAL;
2253                         if (old) {
2254                                 /*
2255                                  * Check against file->f_op because CUSE
2256                                  * uses the same ioctl handler.
2257                                  */
2258                                 if (old->f_op == file->f_op &&
2259                                     old->f_cred->user_ns == file->f_cred->user_ns)
2260                                         fud = fuse_get_dev(old);
2261
2262                                 if (fud) {
2263                                         mutex_lock(&fuse_mutex);
2264                                         res = fuse_device_clone(fud->fc, file);
2265                                         mutex_unlock(&fuse_mutex);
2266                                 }
2267                                 fput(old);
2268                         }
2269                 }
2270                 break;
2271         default:
2272                 res = -ENOTTY;
2273                 break;
2274         }
2275         return res;
2276 }
2277
2278 const struct file_operations fuse_dev_operations = {
2279         .owner          = THIS_MODULE,
2280         .open           = fuse_dev_open,
2281         .llseek         = no_llseek,
2282         .read_iter      = fuse_dev_read,
2283         .splice_read    = fuse_dev_splice_read,
2284         .write_iter     = fuse_dev_write,
2285         .splice_write   = fuse_dev_splice_write,
2286         .poll           = fuse_dev_poll,
2287         .release        = fuse_dev_release,
2288         .fasync         = fuse_dev_fasync,
2289         .unlocked_ioctl = fuse_dev_ioctl,
2290         .compat_ioctl   = compat_ptr_ioctl,
2291 };
2292 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2293
2294 static struct miscdevice fuse_miscdevice = {
2295         .minor = FUSE_MINOR,
2296         .name  = "fuse",
2297         .fops = &fuse_dev_operations,
2298 };
2299
2300 int __init fuse_dev_init(void)
2301 {
2302         int err = -ENOMEM;
2303         fuse_req_cachep = kmem_cache_create("fuse_request",
2304                                             sizeof(struct fuse_req),
2305                                             0, 0, NULL);
2306         if (!fuse_req_cachep)
2307                 goto out;
2308
2309         err = misc_register(&fuse_miscdevice);
2310         if (err)
2311                 goto out_cache_clean;
2312
2313         return 0;
2314
2315  out_cache_clean:
2316         kmem_cache_destroy(fuse_req_cachep);
2317  out:
2318         return err;
2319 }
2320
2321 void fuse_dev_cleanup(void)
2322 {
2323         misc_deregister(&fuse_miscdevice);
2324         kmem_cache_destroy(fuse_req_cachep);
2325 }