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_req *req, struct page **pages,
  44                               struct fuse_page_desc *page_descs,
  45                               unsigned npages)
  46 {
  47         memset(req, 0, sizeof(*req));
  48         memset(pages, 0, sizeof(*pages) * npages);
  49         memset(page_descs, 0, sizeof(*page_descs) * npages);
  50         INIT_LIST_HEAD(&req->list);
  51         INIT_LIST_HEAD(&req->intr_entry);
  52         init_waitqueue_head(&req->waitq);
  53         refcount_set(&req->count, 1);
  54         req->pages = pages;
  55         req->page_descs = page_descs;
  56         req->max_pages = npages;
  57         __set_bit(FR_PENDING, &req->flags);
  58 }
  59
  60 static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
  61 {
  62         struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
  63         if (req) {
  64                 struct page **pages;
  65                 struct fuse_page_desc *page_descs;
  66
  67                 if (npages <= FUSE_REQ_INLINE_PAGES) {
  68                         pages = req->inline_pages;
  69                         page_descs = req->inline_page_descs;
  70                 } else {
  71                         pages = kmalloc_array(npages, sizeof(struct page *),
  72                                               flags);
  73                         page_descs =
  74                                 kmalloc_array(npages,
  75                                               sizeof(struct fuse_page_desc),
  76                                               flags);
  77                 }
  78
  79                 if (!pages || !page_descs) {
  80                         kfree(pages);
  81                         kfree(page_descs);
  82                         kmem_cache_free(fuse_req_cachep, req);
  83                         return NULL;
  84                 }
  85
  86                 fuse_request_init(req, pages, page_descs, npages);
  87         }
  88         return req;
  89 }
  90
  91 struct fuse_req *fuse_request_alloc(unsigned npages)
  92 {
  93         return __fuse_request_alloc(npages, GFP_KERNEL);
  94 }
  95 EXPORT_SYMBOL_GPL(fuse_request_alloc);
  96
  97 struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
  98 {
  99         return __fuse_request_alloc(npages, GFP_NOFS);
 100 }
 101
 102 void fuse_request_free(struct fuse_req *req)
 103 {
 104         if (req->pages != req->inline_pages) {
 105                 kfree(req->pages);
 106                 kfree(req->page_descs);
 107         }
 108         kmem_cache_free(fuse_req_cachep, req);
 109 }
 110
 111 void __fuse_get_request(struct fuse_req *req)
 112 {
 113         refcount_inc(&req->count);
 114 }
 115
 116 /* Must be called with > 1 refcount */
 117 static void __fuse_put_request(struct fuse_req *req)
 118 {
 119         refcount_dec(&req->count);
 120 }
 121
 122 void fuse_set_initialized(struct fuse_conn *fc)
 123 {
 124         /* Make sure stores before this are seen on another CPU */
 125         smp_wmb();
 126         fc->initialized = 1;
 127 }
 128
 129 static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 130 {
 131         return !fc->initialized || (for_background && fc->blocked);
 132 }
 133
 134 static void fuse_drop_waiting(struct fuse_conn *fc)
 135 {
 136         if (fc->connected) {
 137                 atomic_dec(&fc->num_waiting);
 138         } else if (atomic_dec_and_test(&fc->num_waiting)) {
 139                 /* wake up aborters */
 140                 wake_up_all(&fc->blocked_waitq);
 141         }
 142 }
 143
 144 static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
 145                                        bool for_background)
 146 {
 147         struct fuse_req *req;
 148         int err;
 149         atomic_inc(&fc->num_waiting);
 150
 151         if (fuse_block_alloc(fc, for_background)) {
 152                 err = -EINTR;
 153                 if (wait_event_killable_exclusive(fc->blocked_waitq,
 154                                 !fuse_block_alloc(fc, for_background)))
 155                         goto out;
 156         }
 157         /* Matches smp_wmb() in fuse_set_initialized() */
 158         smp_rmb();
 159
 160         err = -ENOTCONN;
 161         if (!fc->connected)
 162                 goto out;
 163
 164         err = -ECONNREFUSED;
 165         if (fc->conn_error)
 166                 goto out;
 167
 168         req = fuse_request_alloc(npages);
 169         err = -ENOMEM;
 170         if (!req) {
 171                 if (for_background)
 172                         wake_up(&fc->blocked_waitq);
 173                 goto out;
 174         }
 175
 176         req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
 177         req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
 178         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 179
 180         __set_bit(FR_WAITING, &req->flags);
 181         if (for_background)
 182                 __set_bit(FR_BACKGROUND, &req->flags);
 183
 184         if (unlikely(req->in.h.uid == ((uid_t)-1) ||
 185                      req->in.h.gid == ((gid_t)-1))) {
 186                 fuse_put_request(fc, req);
 187                 return ERR_PTR(-EOVERFLOW);
 188         }
 189         return req;
 190
 191  out:
 192         fuse_drop_waiting(fc);
 193         return ERR_PTR(err);
 194 }
 195
 196 struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
 197 {
 198         return __fuse_get_req(fc, npages, false);
 199 }
 200 EXPORT_SYMBOL_GPL(fuse_get_req);
 201
 202 struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 203                                              unsigned npages)
 204 {
 205         return __fuse_get_req(fc, npages, true);
 206 }
 207 EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
 208
 209 /*
 210  * Return request in fuse_file->reserved_req.  However that may
 211  * currently be in use.  If that is the case, wait for it to become
 212  * available.
 213  */
 214 static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
 215                                          struct file *file)
 216 {
 217         struct fuse_req *req = NULL;
 218         struct fuse_file *ff = file->private_data;
 219
 220         do {
 221                 wait_event(fc->reserved_req_waitq, ff->reserved_req);
 222                 spin_lock(&fc->lock);
 223                 if (ff->reserved_req) {
 224                         req = ff->reserved_req;
 225                         ff->reserved_req = NULL;
 226                         req->stolen_file = get_file(file);
 227                 }
 228                 spin_unlock(&fc->lock);
 229         } while (!req);
 230
 231         return req;
 232 }
 233
 234 /*
 235  * Put stolen request back into fuse_file->reserved_req
 236  */
 237 static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
 238 {
 239         struct file *file = req->stolen_file;
 240         struct fuse_file *ff = file->private_data;
 241
 242         spin_lock(&fc->lock);
 243         fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
 244         BUG_ON(ff->reserved_req);
 245         ff->reserved_req = req;
 246         wake_up_all(&fc->reserved_req_waitq);
 247         spin_unlock(&fc->lock);
 248         fput(file);
 249 }
 250
 251 /*
 252  * Gets a requests for a file operation, always succeeds
 253  *
 254  * This is used for sending the FLUSH request, which must get to
 255  * userspace, due to POSIX locks which may need to be unlocked.
 256  *
 257  * If allocation fails due to OOM, use the reserved request in
 258  * fuse_file.
 259  *
 260  * This is very unlikely to deadlock accidentally, since the
 261  * filesystem should not have it's own file open.  If deadlock is
 262  * intentional, it can still be broken by "aborting" the filesystem.
 263  */
 264 struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 265                                              struct file *file)
 266 {
 267         struct fuse_req *req;
 268
 269         atomic_inc(&fc->num_waiting);
 270         wait_event(fc->blocked_waitq, fc->initialized);
 271         /* Matches smp_wmb() in fuse_set_initialized() */
 272         smp_rmb();
 273         req = fuse_request_alloc(0);
 274         if (!req)
 275                 req = get_reserved_req(fc, file);
 276
 277         req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
 278         req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
 279         req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 280
 281         __set_bit(FR_WAITING, &req->flags);
 282         __clear_bit(FR_BACKGROUND, &req->flags);
 283         return req;
 284 }
 285
 286 void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 287 {
 288         if (refcount_dec_and_test(&req->count)) {
 289                 if (test_bit(FR_BACKGROUND, &req->flags)) {
 290                         /*
 291                          * We get here in the unlikely case that a background
 292                          * request was allocated but not sent
 293                          */
 294                         spin_lock(&fc->bg_lock);
 295                         if (!fc->blocked)
 296                                 wake_up(&fc->blocked_waitq);
 297                         spin_unlock(&fc->bg_lock);
 298                 }
 299
 300                 if (test_bit(FR_WAITING, &req->flags)) {
 301                         __clear_bit(FR_WAITING, &req->flags);
 302                         fuse_drop_waiting(fc);
 303                 }
 304
 305                 if (req->stolen_file)
 306                         put_reserved_req(fc, req);
 307                 else
 308                         fuse_request_free(req);
 309         }
 310 }
 311 EXPORT_SYMBOL_GPL(fuse_put_request);
 312
 313 static unsigned len_args(unsigned numargs, struct fuse_arg *args)
 314 {
 315         unsigned nbytes = 0;
 316         unsigned i;
 317
 318         for (i = 0; i < numargs; i++)
 319                 nbytes += args[i].size;
 320
 321         return nbytes;
 322 }
 323
 324 static u64 fuse_get_unique(struct fuse_iqueue *fiq)
 325 {
 326         fiq->reqctr += FUSE_REQ_ID_STEP;
 327         return fiq->reqctr;
 328 }
 329
 330 static void queue_request(struct fuse_iqueue *fiq, struct fuse_req *req)
 331 {
 332         req->in.h.len = sizeof(struct fuse_in_header) +
 333                 len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
 334         list_add_tail(&req->list, &fiq->pending);
 335         wake_up_locked(&fiq->waitq);
 336         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 337 }
 338
 339 void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 340                        u64 nodeid, u64 nlookup)
 341 {
 342         struct fuse_iqueue *fiq = &fc->iq;
 343
 344         forget->forget_one.nodeid = nodeid;
 345         forget->forget_one.nlookup = nlookup;
 346
 347         spin_lock(&fiq->waitq.lock);
 348         if (fiq->connected) {
 349                 fiq->forget_list_tail->next = forget;
 350                 fiq->forget_list_tail = forget;
 351                 wake_up_locked(&fiq->waitq);
 352                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 353         } else {
 354                 kfree(forget);
 355         }
 356         spin_unlock(&fiq->waitq.lock);
 357 }
 358
 359 static void flush_bg_queue(struct fuse_conn *fc)
 360 {
 361         struct fuse_iqueue *fiq = &fc->iq;
 362
 363         while (fc->active_background < fc->max_background &&
 364                !list_empty(&fc->bg_queue)) {
 365                 struct fuse_req *req;
 366
 367                 req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
 368                 list_del(&req->list);
 369                 fc->active_background++;
 370                 spin_lock(&fiq->waitq.lock);
 371                 req->in.h.unique = fuse_get_unique(fiq);
 372                 queue_request(fiq, req);
 373                 spin_unlock(&fiq->waitq.lock);
 374         }
 375 }
 376
 377 /*
 378  * This function is called when a request is finished.  Either a reply
 379  * has arrived or it was aborted (and not yet sent) or some error
 380  * occurred during communication with userspace, or the device file
 381  * was closed.  The requester thread is woken up (if still waiting),
 382  * the 'end' callback is called if given, else the reference to the
 383  * request is released
 384  */
 385 static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 386 {
 387         struct fuse_iqueue *fiq = &fc->iq;
 388
 389         if (test_and_set_bit(FR_FINISHED, &req->flags))
 390                 goto put_request;
 391
 392         spin_lock(&fiq->waitq.lock);
 393         list_del_init(&req->intr_entry);
 394         spin_unlock(&fiq->waitq.lock);
 395         WARN_ON(test_bit(FR_PENDING, &req->flags));
 396         WARN_ON(test_bit(FR_SENT, &req->flags));
 397         if (test_bit(FR_BACKGROUND, &req->flags)) {
 398                 spin_lock(&fc->bg_lock);
 399                 clear_bit(FR_BACKGROUND, &req->flags);
 400                 if (fc->num_background == fc->max_background) {
 401                         fc->blocked = 0;
 402                         wake_up(&fc->blocked_waitq);
 403                 } else if (!fc->blocked) {
 404                         /*
 405                          * Wake up next waiter, if any.  It's okay to use
 406                          * waitqueue_active(), as we've already synced up
 407                          * fc->blocked with waiters with the wake_up() call
 408                          * above.
 409                          */
 410                         if (waitqueue_active(&fc->blocked_waitq))
 411                                 wake_up(&fc->blocked_waitq);
 412                 }
 413
 414                 if (fc->num_background == fc->congestion_threshold && fc->sb) {
 415                         clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 416                         clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 417                 }
 418                 fc->num_background--;
 419                 fc->active_background--;
 420                 flush_bg_queue(fc);
 421                 spin_unlock(&fc->bg_lock);
 422         }
 423         wake_up(&req->waitq);
 424         if (req->end)
 425                 req->end(fc, req);
 426 put_request:
 427         fuse_put_request(fc, req);
 428 }
 429
 430 static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
 431 {
 432         spin_lock(&fiq->waitq.lock);
 433         if (test_bit(FR_FINISHED, &req->flags)) {
 434                 spin_unlock(&fiq->waitq.lock);
 435                 return;
 436         }
 437         if (list_empty(&req->intr_entry)) {
 438                 list_add_tail(&req->intr_entry, &fiq->interrupts);
 439                 wake_up_locked(&fiq->waitq);
 440         }
 441         spin_unlock(&fiq->waitq.lock);
 442         kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 443 }
 444
 445 static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 446 {
 447         struct fuse_iqueue *fiq = &fc->iq;
 448         int err;
 449
 450         if (!fc->no_interrupt) {
 451                 /* Any signal may interrupt this */
 452                 err = wait_event_interruptible(req->waitq,
 453                                         test_bit(FR_FINISHED, &req->flags));
 454                 if (!err)
 455                         return;
 456
 457                 set_bit(FR_INTERRUPTED, &req->flags);
 458                 /* matches barrier in fuse_dev_do_read() */
 459                 smp_mb__after_atomic();
 460                 if (test_bit(FR_SENT, &req->flags))
 461                         queue_interrupt(fiq, req);
 462         }
 463
 464         if (!test_bit(FR_FORCE, &req->flags)) {
 465                 /* Only fatal signals may interrupt this */
 466                 err = wait_event_killable(req->waitq,
 467                                         test_bit(FR_FINISHED, &req->flags));
 468                 if (!err)
 469                         return;
 470
 471                 spin_lock(&fiq->waitq.lock);
 472                 /* Request is not yet in userspace, bail out */
 473                 if (test_bit(FR_PENDING, &req->flags)) {
 474                         list_del(&req->list);
 475                         spin_unlock(&fiq->waitq.lock);
 476                         __fuse_put_request(req);
 477                         req->out.h.error = -EINTR;
 478                         return;
 479                 }
 480                 spin_unlock(&fiq->waitq.lock);
 481         }
 482
 483         /*
 484          * Either request is already in userspace, or it was forced.
 485          * Wait it out.
 486          */
 487         wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
 488 }
 489
 490 static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 491 {
 492         struct fuse_iqueue *fiq = &fc->iq;
 493
 494         BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
 495         spin_lock(&fiq->waitq.lock);
 496         if (!fiq->connected) {
 497                 spin_unlock(&fiq->waitq.lock);
 498                 req->out.h.error = -ENOTCONN;
 499         } else {
 500                 req->in.h.unique = fuse_get_unique(fiq);
 501                 queue_request(fiq, req);
 502                 /* acquire extra reference, since request is still needed
 503                    after request_end() */
 504                 __fuse_get_request(req);
 505                 spin_unlock(&fiq->waitq.lock);
 506
 507                 request_wait_answer(fc, req);
 508                 /* Pairs with smp_wmb() in request_end() */
 509                 smp_rmb();
 510         }
 511 }
 512
 513 void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 514 {
 515         __set_bit(FR_ISREPLY, &req->flags);
 516         if (!test_bit(FR_WAITING, &req->flags)) {
 517                 __set_bit(FR_WAITING, &req->flags);
 518                 atomic_inc(&fc->num_waiting);
 519         }
 520         __fuse_request_send(fc, req);
 521 }
 522 EXPORT_SYMBOL_GPL(fuse_request_send);
 523
 524 static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
 525 {
 526         if (fc->minor < 4 && args->in.h.opcode == FUSE_STATFS)
 527                 args->out.args[0].size = FUSE_COMPAT_STATFS_SIZE;
 528
 529         if (fc->minor < 9) {
 530                 switch (args->in.h.opcode) {
 531                 case FUSE_LOOKUP:
 532                 case FUSE_CREATE:
 533                 case FUSE_MKNOD:
 534                 case FUSE_MKDIR:
 535                 case FUSE_SYMLINK:
 536                 case FUSE_LINK:
 537                         args->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 538                         break;
 539                 case FUSE_GETATTR:
 540                 case FUSE_SETATTR:
 541                         args->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 542                         break;
 543                 }
 544         }
 545         if (fc->minor < 12) {
 546                 switch (args->in.h.opcode) {
 547                 case FUSE_CREATE:
 548                         args->in.args[0].size = sizeof(struct fuse_open_in);
 549                         break;
 550                 case FUSE_MKNOD:
 551                         args->in.args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
 552                         break;
 553                 }
 554         }
 555 }
 556
 557 ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 558 {
 559         struct fuse_req *req;
 560         ssize_t ret;
 561
 562         req = fuse_get_req(fc, 0);
 563         if (IS_ERR(req))
 564                 return PTR_ERR(req);
 565
 566         /* Needs to be done after fuse_get_req() so that fc->minor is valid */
 567         fuse_adjust_compat(fc, args);
 568
 569         req->in.h.opcode = args->in.h.opcode;
 570         req->in.h.nodeid = args->in.h.nodeid;
 571         req->in.numargs = args->in.numargs;
 572         memcpy(req->in.args, args->in.args,
 573                args->in.numargs * sizeof(struct fuse_in_arg));
 574         req->out.argvar = args->out.argvar;
 575         req->out.numargs = args->out.numargs;
 576         memcpy(req->out.args, args->out.args,
 577                args->out.numargs * sizeof(struct fuse_arg));
 578         fuse_request_send(fc, req);
 579         ret = req->out.h.error;
 580         if (!ret && args->out.argvar) {
 581                 BUG_ON(args->out.numargs != 1);
 582                 ret = req->out.args[0].size;
 583         }
 584         fuse_put_request(fc, req);
 585
 586         return ret;
 587 }
 588
 589 bool fuse_request_queue_background(struct fuse_conn *fc, struct fuse_req *req)
 590 {
 591         bool queued = false;
 592
 593         WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
 594         if (!test_bit(FR_WAITING, &req->flags)) {
 595                 __set_bit(FR_WAITING, &req->flags);
 596                 atomic_inc(&fc->num_waiting);
 597         }
 598         __set_bit(FR_ISREPLY, &req->flags);
 599         spin_lock(&fc->bg_lock);
 600         if (likely(fc->connected)) {
 601                 fc->num_background++;
 602                 if (fc->num_background == fc->max_background)
 603                         fc->blocked = 1;
 604                 if (fc->num_background == fc->congestion_threshold && fc->sb) {
 605                         set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 606                         set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 607                 }
 608                 list_add_tail(&req->list, &fc->bg_queue);
 609                 flush_bg_queue(fc);
 610                 queued = true;
 611         }
 612         spin_unlock(&fc->bg_lock);
 613
 614         return queued;
 615 }
 616
 617 void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
 618 {
 619         WARN_ON(!req->end);
 620         if (!fuse_request_queue_background(fc, req)) {
 621                 req->out.h.error = -ENOTCONN;
 622                 req->end(fc, req);
 623                 fuse_put_request(fc, req);
 624         }
 625 }
 626 EXPORT_SYMBOL_GPL(fuse_request_send_background);
 627
 628 static int fuse_request_send_notify_reply(struct fuse_conn *fc,
 629                                           struct fuse_req *req, u64 unique)
 630 {
 631         int err = -ENODEV;
 632         struct fuse_iqueue *fiq = &fc->iq;
 633
 634         __clear_bit(FR_ISREPLY, &req->flags);
 635         req->in.h.unique = unique;
 636         spin_lock(&fiq->waitq.lock);
 637         if (fiq->connected) {
 638                 queue_request(fiq, req);
 639                 err = 0;
 640         }
 641         spin_unlock(&fiq->waitq.lock);
 642
 643         return err;
 644 }
 645
 646 void fuse_force_forget(struct file *file, u64 nodeid)
 647 {
 648         struct inode *inode = file_inode(file);
 649         struct fuse_conn *fc = get_fuse_conn(inode);
 650         struct fuse_req *req;
 651         struct fuse_forget_in inarg;
 652
 653         memset(&inarg, 0, sizeof(inarg));
 654         inarg.nlookup = 1;
 655         req = fuse_get_req_nofail_nopages(fc, file);
 656         req->in.h.opcode = FUSE_FORGET;
 657         req->in.h.nodeid = nodeid;
 658         req->in.numargs = 1;
 659         req->in.args[0].size = sizeof(inarg);
 660         req->in.args[0].value = &inarg;
 661         __clear_bit(FR_ISREPLY, &req->flags);
 662         __fuse_request_send(fc, req);
 663         /* ignore errors */
 664         fuse_put_request(fc, req);
 665 }
 666
 667 /*
 668  * Lock the request.  Up to the next unlock_request() there mustn't be
 669  * anything that could cause a page-fault.  If the request was already
 670  * aborted bail out.
 671  */
 672 static int lock_request(struct fuse_req *req)
 673 {
 674         int err = 0;
 675         if (req) {
 676                 spin_lock(&req->waitq.lock);
 677                 if (test_bit(FR_ABORTED, &req->flags))
 678                         err = -ENOENT;
 679                 else
 680                         set_bit(FR_LOCKED, &req->flags);
 681                 spin_unlock(&req->waitq.lock);
 682         }
 683         return err;
 684 }
 685
 686 /*
 687  * Unlock request.  If it was aborted while locked, caller is responsible
 688  * for unlocking and ending the request.
 689  */
 690 static int unlock_request(struct fuse_req *req)
 691 {
 692         int err = 0;
 693         if (req) {
 694                 spin_lock(&req->waitq.lock);
 695                 if (test_bit(FR_ABORTED, &req->flags))
 696                         err = -ENOENT;
 697                 else
 698                         clear_bit(FR_LOCKED, &req->flags);
 699                 spin_unlock(&req->waitq.lock);
 700         }
 701         return err;
 702 }
 703
 704 struct fuse_copy_state {
 705         int write;
 706         struct fuse_req *req;
 707         struct iov_iter *iter;
 708         struct pipe_buffer *pipebufs;
 709         struct pipe_buffer *currbuf;
 710         struct pipe_inode_info *pipe;
 711         unsigned long nr_segs;
 712         struct page *pg;
 713         unsigned len;
 714         unsigned offset;
 715         unsigned move_pages:1;
 716 };
 717
 718 static void fuse_copy_init(struct fuse_copy_state *cs, int write,
 719                            struct iov_iter *iter)
 720 {
 721         memset(cs, 0, sizeof(*cs));
 722         cs->write = write;
 723         cs->iter = iter;
 724 }
 725
 726 /* Unmap and put previous page of userspace buffer */
 727 static void fuse_copy_finish(struct fuse_copy_state *cs)
 728 {
 729         if (cs->currbuf) {
 730                 struct pipe_buffer *buf = cs->currbuf;
 731
 732                 if (cs->write)
 733                         buf->len = PAGE_SIZE - cs->len;
 734                 cs->currbuf = NULL;
 735         } else if (cs->pg) {
 736                 if (cs->write) {
 737                         flush_dcache_page(cs->pg);
 738                         set_page_dirty_lock(cs->pg);
 739                 }
 740                 put_page(cs->pg);
 741         }
 742         cs->pg = NULL;
 743 }
 744
 745 /*
 746  * Get another pagefull of userspace buffer, and map it to kernel
 747  * address space, and lock request
 748  */
 749 static int fuse_copy_fill(struct fuse_copy_state *cs)
 750 {
 751         struct page *page;
 752         int err;
 753
 754         err = unlock_request(cs->req);
 755         if (err)
 756                 return err;
 757
 758         fuse_copy_finish(cs);
 759         if (cs->pipebufs) {
 760                 struct pipe_buffer *buf = cs->pipebufs;
 761
 762                 if (!cs->write) {
 763                         err = pipe_buf_confirm(cs->pipe, buf);
 764                         if (err)
 765                                 return err;
 766
 767                         BUG_ON(!cs->nr_segs);
 768                         cs->currbuf = buf;
 769                         cs->pg = buf->page;
 770                         cs->offset = buf->offset;
 771                         cs->len = buf->len;
 772                         cs->pipebufs++;
 773                         cs->nr_segs--;
 774                 } else {
 775                         if (cs->nr_segs == cs->pipe->buffers)
 776                                 return -EIO;
 777
 778                         page = alloc_page(GFP_HIGHUSER);
 779                         if (!page)
 780                                 return -ENOMEM;
 781
 782                         buf->page = page;
 783                         buf->offset = 0;
 784                         buf->len = 0;
 785
 786                         cs->currbuf = buf;
 787                         cs->pg = page;
 788                         cs->offset = 0;
 789                         cs->len = PAGE_SIZE;
 790                         cs->pipebufs++;
 791                         cs->nr_segs++;
 792                 }
 793         } else {
 794                 size_t off;
 795                 err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
 796                 if (err < 0)
 797                         return err;
 798                 BUG_ON(!err);
 799                 cs->len = err;
 800                 cs->offset = off;
 801                 cs->pg = page;
 802                 iov_iter_advance(cs->iter, err);
 803         }
 804
 805         return lock_request(cs->req);
 806 }
 807
 808 /* Do as much copy to/from userspace buffer as we can */
 809 static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 810 {
 811         unsigned ncpy = min(*size, cs->len);
 812         if (val) {
 813                 void *pgaddr = kmap_atomic(cs->pg);
 814                 void *buf = pgaddr + cs->offset;
 815
 816                 if (cs->write)
 817                         memcpy(buf, *val, ncpy);
 818                 else
 819                         memcpy(*val, buf, ncpy);
 820
 821                 kunmap_atomic(pgaddr);
 822                 *val += ncpy;
 823         }
 824         *size -= ncpy;
 825         cs->len -= ncpy;
 826         cs->offset += ncpy;
 827         return ncpy;
 828 }
 829
 830 static int fuse_check_page(struct page *page)
 831 {
 832         if (page_mapcount(page) ||
 833             page->mapping != NULL ||
 834             page_count(page) != 1 ||
 835             (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 836              ~(1 << PG_locked |
 837                1 << PG_referenced |
 838                1 << PG_uptodate |
 839                1 << PG_lru |
 840                1 << PG_active |
 841                1 << PG_reclaim))) {
 842                 printk(KERN_WARNING "fuse: trying to steal weird page\n");
 843                 printk(KERN_WARNING "  page=%p index=%li flags=%08lx, count=%i, mapcount=%i, mapping=%p\n", page, page->index, page->flags, page_count(page), page_mapcount(page), page->mapping);
 844                 return 1;
 845         }
 846         return 0;
 847 }
 848
 849 static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 850 {
 851         int err;
 852         struct page *oldpage = *pagep;
 853         struct page *newpage;
 854         struct pipe_buffer *buf = cs->pipebufs;
 855
 856         err = unlock_request(cs->req);
 857         if (err)
 858                 return err;
 859
 860         fuse_copy_finish(cs);
 861
 862         err = pipe_buf_confirm(cs->pipe, buf);
 863         if (err)
 864                 return err;
 865
 866         BUG_ON(!cs->nr_segs);
 867         cs->currbuf = buf;
 868         cs->len = buf->len;
 869         cs->pipebufs++;
 870         cs->nr_segs--;
 871
 872         if (cs->len != PAGE_SIZE)
 873                 goto out_fallback;
 874
 875         if (pipe_buf_steal(cs->pipe, buf) != 0)
 876                 goto out_fallback;
 877
 878         newpage = buf->page;
 879
 880         if (!PageUptodate(newpage))
 881                 SetPageUptodate(newpage);
 882
 883         ClearPageMappedToDisk(newpage);
 884
 885         if (fuse_check_page(newpage) != 0)
 886                 goto out_fallback_unlock;
 887
 888         /*
 889          * This is a new and locked page, it shouldn't be mapped or
 890          * have any special flags on it
 891          */
 892         if (WARN_ON(page_mapped(oldpage)))
 893                 goto out_fallback_unlock;
 894         if (WARN_ON(page_has_private(oldpage)))
 895                 goto out_fallback_unlock;
 896         if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 897                 goto out_fallback_unlock;
 898         if (WARN_ON(PageMlocked(oldpage)))
 899                 goto out_fallback_unlock;
 900
 901         err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 902         if (err) {
 903                 unlock_page(newpage);
 904                 return err;
 905         }
 906
 907         get_page(newpage);
 908
 909         if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 910                 lru_cache_add_file(newpage);
 911
 912         err = 0;
 913         spin_lock(&cs->req->waitq.lock);
 914         if (test_bit(FR_ABORTED, &cs->req->flags))
 915                 err = -ENOENT;
 916         else
 917                 *pagep = newpage;
 918         spin_unlock(&cs->req->waitq.lock);
 919
 920         if (err) {
 921                 unlock_page(newpage);
 922                 put_page(newpage);
 923                 return err;
 924         }
 925
 926         unlock_page(oldpage);
 927         put_page(oldpage);
 928         cs->len = 0;
 929
 930         return 0;
 931
 932 out_fallback_unlock:
 933         unlock_page(newpage);
 934 out_fallback:
 935         cs->pg = buf->page;
 936         cs->offset = buf->offset;
 937
 938         err = lock_request(cs->req);
 939         if (err)
 940                 return err;
 941
 942         return 1;
 943 }
 944
 945 static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 946                          unsigned offset, unsigned count)
 947 {
 948         struct pipe_buffer *buf;
 949         int err;
 950
 951         if (cs->nr_segs == cs->pipe->buffers)
 952                 return -EIO;
 953
 954         err = unlock_request(cs->req);
 955         if (err)
 956                 return err;
 957
 958         fuse_copy_finish(cs);
 959
 960         buf = cs->pipebufs;
 961         get_page(page);
 962         buf->page = page;
 963         buf->offset = offset;
 964         buf->len = count;
 965
 966         cs->pipebufs++;
 967         cs->nr_segs++;
 968         cs->len = 0;
 969
 970         return 0;
 971 }
 972
 973 /*
 974  * Copy a page in the request to/from the userspace buffer.  Must be
 975  * done atomically
 976  */
 977 static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 978                           unsigned offset, unsigned count, int zeroing)
 979 {
 980         int err;
 981         struct page *page = *pagep;
 982
 983         if (page && zeroing && count < PAGE_SIZE)
 984                 clear_highpage(page);
 985
 986         while (count) {
 987                 if (cs->write && cs->pipebufs && page) {
 988                         return fuse_ref_page(cs, page, offset, count);
 989                 } else if (!cs->len) {
 990                         if (cs->move_pages && page &&
 991                             offset == 0 && count == PAGE_SIZE) {
 992                                 err = fuse_try_move_page(cs, pagep);
 993                                 if (err <= 0)
 994                                         return err;
 995                         } else {
 996                                 err = fuse_copy_fill(cs);
 997                                 if (err)
 998                                         return err;
 999                         }
1000                 }
1001                 if (page) {
1002                         void *mapaddr = kmap_atomic(page);
1003                         void *buf = mapaddr + offset;
1004                         offset += fuse_copy_do(cs, &buf, &count);
1005                         kunmap_atomic(mapaddr);
1006                 } else
1007                         offset += fuse_copy_do(cs, NULL, &count);
1008         }
1009         if (page && !cs->write)
1010                 flush_dcache_page(page);
1011         return 0;
1012 }
1013
1014 /* Copy pages in the request to/from userspace buffer */
1015 static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
1016                            int zeroing)
1017 {
1018         unsigned i;
1019         struct fuse_req *req = cs->req;
1020
1021         for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
1022                 int err;
1023                 unsigned offset = req->page_descs[i].offset;
1024                 unsigned count = min(nbytes, req->page_descs[i].length);
1025
1026                 err = fuse_copy_page(cs, &req->pages[i], offset, count,
1027                                      zeroing);
1028                 if (err)
1029                         return err;
1030
1031                 nbytes -= count;
1032         }
1033         return 0;
1034 }
1035
1036 /* Copy a single argument in the request to/from userspace buffer */
1037 static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
1038 {
1039         while (size) {
1040                 if (!cs->len) {
1041                         int err = fuse_copy_fill(cs);
1042                         if (err)
1043                                 return err;
1044                 }
1045                 fuse_copy_do(cs, &val, &size);
1046         }
1047         return 0;
1048 }
1049
1050 /* Copy request arguments to/from userspace buffer */
1051 static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
1052                           unsigned argpages, struct fuse_arg *args,
1053                           int zeroing)
1054 {
1055         int err = 0;
1056         unsigned i;
1057
1058         for (i = 0; !err && i < numargs; i++)  {
1059                 struct fuse_arg *arg = &args[i];
1060                 if (i == numargs - 1 && argpages)
1061                         err = fuse_copy_pages(cs, arg->size, zeroing);
1062                 else
1063                         err = fuse_copy_one(cs, arg->value, arg->size);
1064         }
1065         return err;
1066 }
1067
1068 static int forget_pending(struct fuse_iqueue *fiq)
1069 {
1070         return fiq->forget_list_head.next != NULL;
1071 }
1072
1073 static int request_pending(struct fuse_iqueue *fiq)
1074 {
1075         return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1076                 forget_pending(fiq);
1077 }
1078
1079 /*
1080  * Transfer an interrupt request to userspace
1081  *
1082  * Unlike other requests this is assembled on demand, without a need
1083  * to allocate a separate fuse_req structure.
1084  *
1085  * Called with fiq->waitq.lock held, releases it
1086  */
1087 static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1088                                struct fuse_copy_state *cs,
1089                                size_t nbytes, struct fuse_req *req)
1090 __releases(fiq->waitq.lock)
1091 {
1092         struct fuse_in_header ih;
1093         struct fuse_interrupt_in arg;
1094         unsigned reqsize = sizeof(ih) + sizeof(arg);
1095         int err;
1096
1097         list_del_init(&req->intr_entry);
1098         req->intr_unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1099         memset(&ih, 0, sizeof(ih));
1100         memset(&arg, 0, sizeof(arg));
1101         ih.len = reqsize;
1102         ih.opcode = FUSE_INTERRUPT;
1103         ih.unique = req->intr_unique;
1104         arg.unique = req->in.h.unique;
1105
1106         spin_unlock(&fiq->waitq.lock);
1107         if (nbytes < reqsize)
1108                 return -EINVAL;
1109
1110         err = fuse_copy_one(cs, &ih, sizeof(ih));
1111         if (!err)
1112                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1113         fuse_copy_finish(cs);
1114
1115         return err ? err : reqsize;
1116 }
1117
1118 static struct fuse_forget_link *dequeue_forget(struct fuse_iqueue *fiq,
1119                                                unsigned max,
1120                                                unsigned *countp)
1121 {
1122         struct fuse_forget_link *head = fiq->forget_list_head.next;
1123         struct fuse_forget_link **newhead = &head;
1124         unsigned count;
1125
1126         for (count = 0; *newhead != NULL && count < max; count++)
1127                 newhead = &(*newhead)->next;
1128
1129         fiq->forget_list_head.next = *newhead;
1130         *newhead = NULL;
1131         if (fiq->forget_list_head.next == NULL)
1132                 fiq->forget_list_tail = &fiq->forget_list_head;
1133
1134         if (countp != NULL)
1135                 *countp = count;
1136
1137         return head;
1138 }
1139
1140 static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1141                                    struct fuse_copy_state *cs,
1142                                    size_t nbytes)
1143 __releases(fiq->waitq.lock)
1144 {
1145         int err;
1146         struct fuse_forget_link *forget = dequeue_forget(fiq, 1, NULL);
1147         struct fuse_forget_in arg = {
1148                 .nlookup = forget->forget_one.nlookup,
1149         };
1150         struct fuse_in_header ih = {
1151                 .opcode = FUSE_FORGET,
1152                 .nodeid = forget->forget_one.nodeid,
1153                 .unique = fuse_get_unique(fiq),
1154                 .len = sizeof(ih) + sizeof(arg),
1155         };
1156
1157         spin_unlock(&fiq->waitq.lock);
1158         kfree(forget);
1159         if (nbytes < ih.len)
1160                 return -EINVAL;
1161
1162         err = fuse_copy_one(cs, &ih, sizeof(ih));
1163         if (!err)
1164                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1165         fuse_copy_finish(cs);
1166
1167         if (err)
1168                 return err;
1169
1170         return ih.len;
1171 }
1172
1173 static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1174                                    struct fuse_copy_state *cs, size_t nbytes)
1175 __releases(fiq->waitq.lock)
1176 {
1177         int err;
1178         unsigned max_forgets;
1179         unsigned count;
1180         struct fuse_forget_link *head;
1181         struct fuse_batch_forget_in arg = { .count = 0 };
1182         struct fuse_in_header ih = {
1183                 .opcode = FUSE_BATCH_FORGET,
1184                 .unique = fuse_get_unique(fiq),
1185                 .len = sizeof(ih) + sizeof(arg),
1186         };
1187
1188         if (nbytes < ih.len) {
1189                 spin_unlock(&fiq->waitq.lock);
1190                 return -EINVAL;
1191         }
1192
1193         max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1194         head = dequeue_forget(fiq, max_forgets, &count);
1195         spin_unlock(&fiq->waitq.lock);
1196
1197         arg.count = count;
1198         ih.len += count * sizeof(struct fuse_forget_one);
1199         err = fuse_copy_one(cs, &ih, sizeof(ih));
1200         if (!err)
1201                 err = fuse_copy_one(cs, &arg, sizeof(arg));
1202
1203         while (head) {
1204                 struct fuse_forget_link *forget = head;
1205
1206                 if (!err) {
1207                         err = fuse_copy_one(cs, &forget->forget_one,
1208                                             sizeof(forget->forget_one));
1209                 }
1210                 head = forget->next;
1211                 kfree(forget);
1212         }
1213
1214         fuse_copy_finish(cs);
1215
1216         if (err)
1217                 return err;
1218
1219         return ih.len;
1220 }
1221
1222 static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1223                             struct fuse_copy_state *cs,
1224                             size_t nbytes)
1225 __releases(fiq->waitq.lock)
1226 {
1227         if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1228                 return fuse_read_single_forget(fiq, cs, nbytes);
1229         else
1230                 return fuse_read_batch_forget(fiq, cs, nbytes);
1231 }
1232
1233 /*
1234  * Read a single request into the userspace filesystem's buffer.  This
1235  * function waits until a request is available, then removes it from
1236  * the pending list and copies request data to userspace buffer.  If
1237  * no reply is needed (FORGET) or request has been aborted or there
1238  * was an error during the copying then it's finished by calling
1239  * request_end().  Otherwise add it to the processing list, and set
1240  * the 'sent' flag.
1241  */
1242 static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1243                                 struct fuse_copy_state *cs, size_t nbytes)
1244 {
1245         ssize_t err;
1246         struct fuse_conn *fc = fud->fc;
1247         struct fuse_iqueue *fiq = &fc->iq;
1248         struct fuse_pqueue *fpq = &fud->pq;
1249         struct fuse_req *req;
1250         struct fuse_in *in;
1251         unsigned reqsize;
1252
1253  restart:
1254         spin_lock(&fiq->waitq.lock);
1255         err = -EAGAIN;
1256         if ((file->f_flags & O_NONBLOCK) && fiq->connected &&
1257             !request_pending(fiq))
1258                 goto err_unlock;
1259
1260         err = wait_event_interruptible_exclusive_locked(fiq->waitq,
1261                                 !fiq->connected || request_pending(fiq));
1262         if (err)
1263                 goto err_unlock;
1264
1265         if (!fiq->connected) {
1266                 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1267                 goto err_unlock;
1268         }
1269
1270         if (!list_empty(&fiq->interrupts)) {
1271                 req = list_entry(fiq->interrupts.next, struct fuse_req,
1272                                  intr_entry);
1273                 return fuse_read_interrupt(fiq, cs, nbytes, req);
1274         }
1275
1276         if (forget_pending(fiq)) {
1277                 if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1278                         return fuse_read_forget(fc, fiq, cs, nbytes);
1279
1280                 if (fiq->forget_batch <= -8)
1281                         fiq->forget_batch = 16;
1282         }
1283
1284         req = list_entry(fiq->pending.next, struct fuse_req, list);
1285         clear_bit(FR_PENDING, &req->flags);
1286         list_del_init(&req->list);
1287         spin_unlock(&fiq->waitq.lock);
1288
1289         in = &req->in;
1290         reqsize = in->h.len;
1291
1292         /* If request is too large, reply with an error and restart the read */
1293         if (nbytes < reqsize) {
1294                 req->out.h.error = -EIO;
1295                 /* SETXATTR is special, since it may contain too large data */
1296                 if (in->h.opcode == FUSE_SETXATTR)
1297                         req->out.h.error = -E2BIG;
1298                 request_end(fc, req);
1299                 goto restart;
1300         }
1301         spin_lock(&fpq->lock);
1302         list_add(&req->list, &fpq->io);
1303         spin_unlock(&fpq->lock);
1304         cs->req = req;
1305         err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1306         if (!err)
1307                 err = fuse_copy_args(cs, in->numargs, in->argpages,
1308                                      (struct fuse_arg *) in->args, 0);
1309         fuse_copy_finish(cs);
1310         spin_lock(&fpq->lock);
1311         clear_bit(FR_LOCKED, &req->flags);
1312         if (!fpq->connected) {
1313                 err = (fc->aborted && fc->abort_err) ? -ECONNABORTED : -ENODEV;
1314                 goto out_end;
1315         }
1316         if (err) {
1317                 req->out.h.error = -EIO;
1318                 goto out_end;
1319         }
1320         if (!test_bit(FR_ISREPLY, &req->flags)) {
1321                 err = reqsize;
1322                 goto out_end;
1323         }
1324         list_move_tail(&req->list, &fpq->processing);
1325         __fuse_get_request(req);
1326         set_bit(FR_SENT, &req->flags);
1327         spin_unlock(&fpq->lock);
1328         /* matches barrier in request_wait_answer() */
1329         smp_mb__after_atomic();
1330         if (test_bit(FR_INTERRUPTED, &req->flags))
1331                 queue_interrupt(fiq, req);
1332         fuse_put_request(fc, req);
1333
1334         return reqsize;
1335
1336 out_end:
1337         if (!test_bit(FR_PRIVATE, &req->flags))
1338                 list_del_init(&req->list);
1339         spin_unlock(&fpq->lock);
1340         request_end(fc, req);
1341         return err;
1342
1343  err_unlock:
1344         spin_unlock(&fiq->waitq.lock);
1345         return err;
1346 }
1347
1348 static int fuse_dev_open(struct inode *inode, struct file *file)
1349 {
1350         /*
1351          * The fuse device's file's private_data is used to hold
1352          * the fuse_conn(ection) when it is mounted, and is used to
1353          * keep track of whether the file has been mounted already.
1354          */
1355         file->private_data = NULL;
1356         return 0;
1357 }
1358
1359 static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1360 {
1361         struct fuse_copy_state cs;
1362         struct file *file = iocb->ki_filp;
1363         struct fuse_dev *fud = fuse_get_dev(file);
1364
1365         if (!fud)
1366                 return -EPERM;
1367
1368         if (!iter_is_iovec(to))
1369                 return -EINVAL;
1370
1371         fuse_copy_init(&cs, 1, to);
1372
1373         return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1374 }
1375
1376 static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1377                                     struct pipe_inode_info *pipe,
1378                                     size_t len, unsigned int flags)
1379 {
1380         int total, ret;
1381         int page_nr = 0;
1382         struct pipe_buffer *bufs;
1383         struct fuse_copy_state cs;
1384         struct fuse_dev *fud = fuse_get_dev(in);
1385
1386         if (!fud)
1387                 return -EPERM;
1388
1389         bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1390                               GFP_KERNEL);
1391         if (!bufs)
1392                 return -ENOMEM;
1393
1394         fuse_copy_init(&cs, 1, NULL);
1395         cs.pipebufs = bufs;
1396         cs.pipe = pipe;
1397         ret = fuse_dev_do_read(fud, in, &cs, len);
1398         if (ret < 0)
1399                 goto out;
1400
1401         if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1402                 ret = -EIO;
1403                 goto out;
1404         }
1405
1406         for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1407                 /*
1408                  * Need to be careful about this.  Having buf->ops in module
1409                  * code can Oops if the buffer persists after module unload.
1410                  */
1411                 bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1412                 bufs[page_nr].flags = 0;
1413                 ret = add_to_pipe(pipe, &bufs[page_nr++]);
1414                 if (unlikely(ret < 0))
1415                         break;
1416         }
1417         if (total)
1418                 ret = total;
1419 out:
1420         for (; page_nr < cs.nr_segs; page_nr++)
1421                 put_page(bufs[page_nr].page);
1422
1423         kvfree(bufs);
1424         return ret;
1425 }
1426
1427 static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1428                             struct fuse_copy_state *cs)
1429 {
1430         struct fuse_notify_poll_wakeup_out outarg;
1431         int err = -EINVAL;
1432
1433         if (size != sizeof(outarg))
1434                 goto err;
1435
1436         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1437         if (err)
1438                 goto err;
1439
1440         fuse_copy_finish(cs);
1441         return fuse_notify_poll_wakeup(fc, &outarg);
1442
1443 err:
1444         fuse_copy_finish(cs);
1445         return err;
1446 }
1447
1448 static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1449                                    struct fuse_copy_state *cs)
1450 {
1451         struct fuse_notify_inval_inode_out outarg;
1452         int err = -EINVAL;
1453
1454         if (size != sizeof(outarg))
1455                 goto err;
1456
1457         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1458         if (err)
1459                 goto err;
1460         fuse_copy_finish(cs);
1461
1462         down_read(&fc->killsb);
1463         err = -ENOENT;
1464         if (fc->sb) {
1465                 err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1466                                                outarg.off, outarg.len);
1467         }
1468         up_read(&fc->killsb);
1469         return err;
1470
1471 err:
1472         fuse_copy_finish(cs);
1473         return err;
1474 }
1475
1476 static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1477                                    struct fuse_copy_state *cs)
1478 {
1479         struct fuse_notify_inval_entry_out outarg;
1480         int err = -ENOMEM;
1481         char *buf;
1482         struct qstr name;
1483
1484         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1485         if (!buf)
1486                 goto err;
1487
1488         err = -EINVAL;
1489         if (size < sizeof(outarg))
1490                 goto err;
1491
1492         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1493         if (err)
1494                 goto err;
1495
1496         err = -ENAMETOOLONG;
1497         if (outarg.namelen > FUSE_NAME_MAX)
1498                 goto err;
1499
1500         err = -EINVAL;
1501         if (size != sizeof(outarg) + outarg.namelen + 1)
1502                 goto err;
1503
1504         name.name = buf;
1505         name.len = outarg.namelen;
1506         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1507         if (err)
1508                 goto err;
1509         fuse_copy_finish(cs);
1510         buf[outarg.namelen] = 0;
1511
1512         down_read(&fc->killsb);
1513         err = -ENOENT;
1514         if (fc->sb)
1515                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1516         up_read(&fc->killsb);
1517         kfree(buf);
1518         return err;
1519
1520 err:
1521         kfree(buf);
1522         fuse_copy_finish(cs);
1523         return err;
1524 }
1525
1526 static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1527                               struct fuse_copy_state *cs)
1528 {
1529         struct fuse_notify_delete_out outarg;
1530         int err = -ENOMEM;
1531         char *buf;
1532         struct qstr name;
1533
1534         buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1535         if (!buf)
1536                 goto err;
1537
1538         err = -EINVAL;
1539         if (size < sizeof(outarg))
1540                 goto err;
1541
1542         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1543         if (err)
1544                 goto err;
1545
1546         err = -ENAMETOOLONG;
1547         if (outarg.namelen > FUSE_NAME_MAX)
1548                 goto err;
1549
1550         err = -EINVAL;
1551         if (size != sizeof(outarg) + outarg.namelen + 1)
1552                 goto err;
1553
1554         name.name = buf;
1555         name.len = outarg.namelen;
1556         err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1557         if (err)
1558                 goto err;
1559         fuse_copy_finish(cs);
1560         buf[outarg.namelen] = 0;
1561
1562         down_read(&fc->killsb);
1563         err = -ENOENT;
1564         if (fc->sb)
1565                 err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1566                                                outarg.child, &name);
1567         up_read(&fc->killsb);
1568         kfree(buf);
1569         return err;
1570
1571 err:
1572         kfree(buf);
1573         fuse_copy_finish(cs);
1574         return err;
1575 }
1576
1577 static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1578                              struct fuse_copy_state *cs)
1579 {
1580         struct fuse_notify_store_out outarg;
1581         struct inode *inode;
1582         struct address_space *mapping;
1583         u64 nodeid;
1584         int err;
1585         pgoff_t index;
1586         unsigned int offset;
1587         unsigned int num;
1588         loff_t file_size;
1589         loff_t end;
1590
1591         err = -EINVAL;
1592         if (size < sizeof(outarg))
1593                 goto out_finish;
1594
1595         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1596         if (err)
1597                 goto out_finish;
1598
1599         err = -EINVAL;
1600         if (size - sizeof(outarg) != outarg.size)
1601                 goto out_finish;
1602
1603         nodeid = outarg.nodeid;
1604
1605         down_read(&fc->killsb);
1606
1607         err = -ENOENT;
1608         if (!fc->sb)
1609                 goto out_up_killsb;
1610
1611         inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1612         if (!inode)
1613                 goto out_up_killsb;
1614
1615         mapping = inode->i_mapping;
1616         index = outarg.offset >> PAGE_SHIFT;
1617         offset = outarg.offset & ~PAGE_MASK;
1618         file_size = i_size_read(inode);
1619         end = outarg.offset + outarg.size;
1620         if (end > file_size) {
1621                 file_size = end;
1622                 fuse_write_update_size(inode, file_size);
1623         }
1624
1625         num = outarg.size;
1626         while (num) {
1627                 struct page *page;
1628                 unsigned int this_num;
1629
1630                 err = -ENOMEM;
1631                 page = find_or_create_page(mapping, index,
1632                                            mapping_gfp_mask(mapping));
1633                 if (!page)
1634                         goto out_iput;
1635
1636                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1637                 err = fuse_copy_page(cs, &page, offset, this_num, 0);
1638                 if (!err && offset == 0 &&
1639                     (this_num == PAGE_SIZE || file_size == end))
1640                         SetPageUptodate(page);
1641                 unlock_page(page);
1642                 put_page(page);
1643
1644                 if (err)
1645                         goto out_iput;
1646
1647                 num -= this_num;
1648                 offset = 0;
1649                 index++;
1650         }
1651
1652         err = 0;
1653
1654 out_iput:
1655         iput(inode);
1656 out_up_killsb:
1657         up_read(&fc->killsb);
1658 out_finish:
1659         fuse_copy_finish(cs);
1660         return err;
1661 }
1662
1663 static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1664 {
1665         release_pages(req->pages, req->num_pages);
1666 }
1667
1668 static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1669                          struct fuse_notify_retrieve_out *outarg)
1670 {
1671         int err;
1672         struct address_space *mapping = inode->i_mapping;
1673         struct fuse_req *req;
1674         pgoff_t index;
1675         loff_t file_size;
1676         unsigned int num;
1677         unsigned int offset;
1678         size_t total_len = 0;
1679         int num_pages;
1680
1681         offset = outarg->offset & ~PAGE_MASK;
1682         file_size = i_size_read(inode);
1683
1684         num = outarg->size;
1685         if (outarg->offset > file_size)
1686                 num = 0;
1687         else if (outarg->offset + num > file_size)
1688                 num = file_size - outarg->offset;
1689
1690         num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1691         num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1692
1693         req = fuse_get_req(fc, num_pages);
1694         if (IS_ERR(req))
1695                 return PTR_ERR(req);
1696
1697         req->in.h.opcode = FUSE_NOTIFY_REPLY;
1698         req->in.h.nodeid = outarg->nodeid;
1699         req->in.numargs = 2;
1700         req->in.argpages = 1;
1701         req->page_descs[0].offset = offset;
1702         req->end = fuse_retrieve_end;
1703
1704         index = outarg->offset >> PAGE_SHIFT;
1705
1706         while (num && req->num_pages < num_pages) {
1707                 struct page *page;
1708                 unsigned int this_num;
1709
1710                 page = find_get_page(mapping, index);
1711                 if (!page)
1712                         break;
1713
1714                 this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1715                 req->pages[req->num_pages] = page;
1716                 req->page_descs[req->num_pages].length = this_num;
1717                 req->num_pages++;
1718
1719                 offset = 0;
1720                 num -= this_num;
1721                 total_len += this_num;
1722                 index++;
1723         }
1724         req->misc.retrieve_in.offset = outarg->offset;
1725         req->misc.retrieve_in.size = total_len;
1726         req->in.args[0].size = sizeof(req->misc.retrieve_in);
1727         req->in.args[0].value = &req->misc.retrieve_in;
1728         req->in.args[1].size = total_len;
1729
1730         err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1731         if (err)
1732                 fuse_retrieve_end(fc, req);
1733
1734         return err;
1735 }
1736
1737 static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1738                                 struct fuse_copy_state *cs)
1739 {
1740         struct fuse_notify_retrieve_out outarg;
1741         struct inode *inode;
1742         int err;
1743
1744         err = -EINVAL;
1745         if (size != sizeof(outarg))
1746                 goto copy_finish;
1747
1748         err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1749         if (err)
1750                 goto copy_finish;
1751
1752         fuse_copy_finish(cs);
1753
1754         down_read(&fc->killsb);
1755         err = -ENOENT;
1756         if (fc->sb) {
1757                 u64 nodeid = outarg.nodeid;
1758
1759                 inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1760                 if (inode) {
1761                         err = fuse_retrieve(fc, inode, &outarg);
1762                         iput(inode);
1763                 }
1764         }
1765         up_read(&fc->killsb);
1766
1767         return err;
1768
1769 copy_finish:
1770         fuse_copy_finish(cs);
1771         return err;
1772 }
1773
1774 static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1775                        unsigned int size, struct fuse_copy_state *cs)
1776 {
1777         /* Don't try to move pages (yet) */
1778         cs->move_pages = 0;
1779
1780         switch (code) {
1781         case FUSE_NOTIFY_POLL:
1782                 return fuse_notify_poll(fc, size, cs);
1783
1784         case FUSE_NOTIFY_INVAL_INODE:
1785                 return fuse_notify_inval_inode(fc, size, cs);
1786
1787         case FUSE_NOTIFY_INVAL_ENTRY:
1788                 return fuse_notify_inval_entry(fc, size, cs);
1789
1790         case FUSE_NOTIFY_STORE:
1791                 return fuse_notify_store(fc, size, cs);
1792
1793         case FUSE_NOTIFY_RETRIEVE:
1794                 return fuse_notify_retrieve(fc, size, cs);
1795
1796         case FUSE_NOTIFY_DELETE:
1797                 return fuse_notify_delete(fc, size, cs);
1798
1799         default:
1800                 fuse_copy_finish(cs);
1801                 return -EINVAL;
1802         }
1803 }
1804
1805 /* Look up request on processing list by unique ID */
1806 static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1807 {
1808         struct fuse_req *req;
1809
1810         list_for_each_entry(req, &fpq->processing, list) {
1811                 if (req->in.h.unique == unique || req->intr_unique == unique)
1812                         return req;
1813         }
1814         return NULL;
1815 }
1816
1817 static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1818                          unsigned nbytes)
1819 {
1820         unsigned reqsize = sizeof(struct fuse_out_header);
1821
1822         if (out->h.error)
1823                 return nbytes != reqsize ? -EINVAL : 0;
1824
1825         reqsize += len_args(out->numargs, out->args);
1826
1827         if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1828                 return -EINVAL;
1829         else if (reqsize > nbytes) {
1830                 struct fuse_arg *lastarg = &out->args[out->numargs-1];
1831                 unsigned diffsize = reqsize - nbytes;
1832                 if (diffsize > lastarg->size)
1833                         return -EINVAL;
1834                 lastarg->size -= diffsize;
1835         }
1836         return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1837                               out->page_zeroing);
1838 }
1839
1840 /*
1841  * Write a single reply to a request.  First the header is copied from
1842  * the write buffer.  The request is then searched on the processing
1843  * list by the unique ID found in the header.  If found, then remove
1844  * it from the list and copy the rest of the buffer to the request.
1845  * The request is finished by calling request_end()
1846  */
1847 static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1848                                  struct fuse_copy_state *cs, size_t nbytes)
1849 {
1850         int err;
1851         struct fuse_conn *fc = fud->fc;
1852         struct fuse_pqueue *fpq = &fud->pq;
1853         struct fuse_req *req;
1854         struct fuse_out_header oh;
1855
1856         if (nbytes < sizeof(struct fuse_out_header))
1857                 return -EINVAL;
1858
1859         err = fuse_copy_one(cs, &oh, sizeof(oh));
1860         if (err)
1861                 goto err_finish;
1862
1863         err = -EINVAL;
1864         if (oh.len != nbytes)
1865                 goto err_finish;
1866
1867         /*
1868          * Zero oh.unique indicates unsolicited notification message
1869          * and error contains notification code.
1870          */
1871         if (!oh.unique) {
1872                 err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1873                 return err ? err : nbytes;
1874         }
1875
1876         err = -EINVAL;
1877         if (oh.error <= -1000 || oh.error > 0)
1878                 goto err_finish;
1879
1880         spin_lock(&fpq->lock);
1881         err = -ENOENT;
1882         if (!fpq->connected)
1883                 goto err_unlock_pq;
1884
1885         req = request_find(fpq, oh.unique);
1886         if (!req)
1887                 goto err_unlock_pq;
1888
1889         /* Is it an interrupt reply? */
1890         if (req->intr_unique == oh.unique) {
1891                 __fuse_get_request(req);
1892                 spin_unlock(&fpq->lock);
1893
1894                 err = -EINVAL;
1895                 if (nbytes != sizeof(struct fuse_out_header)) {
1896                         fuse_put_request(fc, req);
1897                         goto err_finish;
1898                 }
1899
1900                 if (oh.error == -ENOSYS)
1901                         fc->no_interrupt = 1;
1902                 else if (oh.error == -EAGAIN)
1903                         queue_interrupt(&fc->iq, req);
1904                 fuse_put_request(fc, req);
1905
1906                 fuse_copy_finish(cs);
1907                 return nbytes;
1908         }
1909
1910         clear_bit(FR_SENT, &req->flags);
1911         list_move(&req->list, &fpq->io);
1912         req->out.h = oh;
1913         set_bit(FR_LOCKED, &req->flags);
1914         spin_unlock(&fpq->lock);
1915         cs->req = req;
1916         if (!req->out.page_replace)
1917                 cs->move_pages = 0;
1918
1919         err = copy_out_args(cs, &req->out, nbytes);
1920         fuse_copy_finish(cs);
1921
1922         spin_lock(&fpq->lock);
1923         clear_bit(FR_LOCKED, &req->flags);
1924         if (!fpq->connected)
1925                 err = -ENOENT;
1926         else if (err)
1927                 req->out.h.error = -EIO;
1928         if (!test_bit(FR_PRIVATE, &req->flags))
1929                 list_del_init(&req->list);
1930         spin_unlock(&fpq->lock);
1931
1932         request_end(fc, req);
1933
1934         return err ? err : nbytes;
1935
1936  err_unlock_pq:
1937         spin_unlock(&fpq->lock);
1938  err_finish:
1939         fuse_copy_finish(cs);
1940         return err;
1941 }
1942
1943 static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1944 {
1945         struct fuse_copy_state cs;
1946         struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1947
1948         if (!fud)
1949                 return -EPERM;
1950
1951         if (!iter_is_iovec(from))
1952                 return -EINVAL;
1953
1954         fuse_copy_init(&cs, 0, from);
1955
1956         return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1957 }
1958
1959 static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1960                                      struct file *out, loff_t *ppos,
1961                                      size_t len, unsigned int flags)
1962 {
1963         unsigned nbuf;
1964         unsigned idx;
1965         struct pipe_buffer *bufs;
1966         struct fuse_copy_state cs;
1967         struct fuse_dev *fud;
1968         size_t rem;
1969         ssize_t ret;
1970
1971         fud = fuse_get_dev(out);
1972         if (!fud)
1973                 return -EPERM;
1974
1975         pipe_lock(pipe);
1976
1977         bufs = kvmalloc_array(pipe->nrbufs, sizeof(struct pipe_buffer),
1978                               GFP_KERNEL);
1979         if (!bufs) {
1980                 pipe_unlock(pipe);
1981                 return -ENOMEM;
1982         }
1983
1984         nbuf = 0;
1985         rem = 0;
1986         for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1987                 rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1988
1989         ret = -EINVAL;
1990         if (rem < len) {
1991                 pipe_unlock(pipe);
1992                 goto out;
1993         }
1994
1995         rem = len;
1996         while (rem) {
1997                 struct pipe_buffer *ibuf;
1998                 struct pipe_buffer *obuf;
1999
2000                 BUG_ON(nbuf >= pipe->buffers);
2001                 BUG_ON(!pipe->nrbufs);
2002                 ibuf = &pipe->bufs[pipe->curbuf];
2003                 obuf = &bufs[nbuf];
2004
2005                 if (rem >= ibuf->len) {
2006                         *obuf = *ibuf;
2007                         ibuf->ops = NULL;
2008                         pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
2009                         pipe->nrbufs--;
2010                 } else {
2011                         pipe_buf_get(pipe, ibuf);
2012                         *obuf = *ibuf;
2013                         obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
2014                         obuf->len = rem;
2015                         ibuf->offset += obuf->len;
2016                         ibuf->len -= obuf->len;
2017                 }
2018                 nbuf++;
2019                 rem -= obuf->len;
2020         }
2021         pipe_unlock(pipe);
2022
2023         fuse_copy_init(&cs, 0, NULL);
2024         cs.pipebufs = bufs;
2025         cs.nr_segs = nbuf;
2026         cs.pipe = pipe;
2027
2028         if (flags & SPLICE_F_MOVE)
2029                 cs.move_pages = 1;
2030
2031         ret = fuse_dev_do_write(fud, &cs, len);
2032
2033         for (idx = 0; idx < nbuf; idx++)
2034                 pipe_buf_release(pipe, &bufs[idx]);
2035
2036 out:
2037         kvfree(bufs);
2038         return ret;
2039 }
2040
2041 static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2042 {
2043         __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2044         struct fuse_iqueue *fiq;
2045         struct fuse_dev *fud = fuse_get_dev(file);
2046
2047         if (!fud)
2048                 return EPOLLERR;
2049
2050         fiq = &fud->fc->iq;
2051         poll_wait(file, &fiq->waitq, wait);
2052
2053         spin_lock(&fiq->waitq.lock);
2054         if (!fiq->connected)
2055                 mask = EPOLLERR;
2056         else if (request_pending(fiq))
2057                 mask |= EPOLLIN | EPOLLRDNORM;
2058         spin_unlock(&fiq->waitq.lock);
2059
2060         return mask;
2061 }
2062
2063 /*
2064  * Abort all requests on the given list (pending or processing)
2065  *
2066  * This function releases and reacquires fc->lock
2067  */
2068 static void end_requests(struct fuse_conn *fc, struct list_head *head)
2069 {
2070         while (!list_empty(head)) {
2071                 struct fuse_req *req;
2072                 req = list_entry(head->next, struct fuse_req, list);
2073                 req->out.h.error = -ECONNABORTED;
2074                 clear_bit(FR_SENT, &req->flags);
2075                 list_del_init(&req->list);
2076                 request_end(fc, req);
2077         }
2078 }
2079
2080 static void end_polls(struct fuse_conn *fc)
2081 {
2082         struct rb_node *p;
2083
2084         p = rb_first(&fc->polled_files);
2085
2086         while (p) {
2087                 struct fuse_file *ff;
2088                 ff = rb_entry(p, struct fuse_file, polled_node);
2089                 wake_up_interruptible_all(&ff->poll_wait);
2090
2091                 p = rb_next(p);
2092         }
2093 }
2094
2095 /*
2096  * Abort all requests.
2097  *
2098  * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2099  * filesystem.
2100  *
2101  * The same effect is usually achievable through killing the filesystem daemon
2102  * and all users of the filesystem.  The exception is the combination of an
2103  * asynchronous request and the tricky deadlock (see
2104  * Documentation/filesystems/fuse.txt).
2105  *
2106  * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2107  * requests, they should be finished off immediately.  Locked requests will be
2108  * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2109  * requests.  It is possible that some request will finish before we can.  This
2110  * is OK, the request will in that case be removed from the list before we touch
2111  * it.
2112  */
2113 void fuse_abort_conn(struct fuse_conn *fc, bool is_abort)
2114 {
2115         struct fuse_iqueue *fiq = &fc->iq;
2116
2117         spin_lock(&fc->lock);
2118         if (fc->connected) {
2119                 struct fuse_dev *fud;
2120                 struct fuse_req *req, *next;
2121                 LIST_HEAD(to_end);
2122
2123                 /* Background queuing checks fc->connected under bg_lock */
2124                 spin_lock(&fc->bg_lock);
2125                 fc->connected = 0;
2126                 spin_unlock(&fc->bg_lock);
2127
2128                 fc->aborted = is_abort;
2129                 fuse_set_initialized(fc);
2130                 list_for_each_entry(fud, &fc->devices, entry) {
2131                         struct fuse_pqueue *fpq = &fud->pq;
2132
2133                         spin_lock(&fpq->lock);
2134                         fpq->connected = 0;
2135                         list_for_each_entry_safe(req, next, &fpq->io, list) {
2136                                 req->out.h.error = -ECONNABORTED;
2137                                 spin_lock(&req->waitq.lock);
2138                                 set_bit(FR_ABORTED, &req->flags);
2139                                 if (!test_bit(FR_LOCKED, &req->flags)) {
2140                                         set_bit(FR_PRIVATE, &req->flags);
2141                                         __fuse_get_request(req);
2142                                         list_move(&req->list, &to_end);
2143                                 }
2144                                 spin_unlock(&req->waitq.lock);
2145                         }
2146                         list_splice_tail_init(&fpq->processing, &to_end);
2147                         spin_unlock(&fpq->lock);
2148                 }
2149                 spin_lock(&fc->bg_lock);
2150                 fc->blocked = 0;
2151                 fc->max_background = UINT_MAX;
2152                 flush_bg_queue(fc);
2153                 spin_unlock(&fc->bg_lock);
2154
2155                 spin_lock(&fiq->waitq.lock);
2156                 fiq->connected = 0;
2157                 list_for_each_entry(req, &fiq->pending, list)
2158                         clear_bit(FR_PENDING, &req->flags);
2159                 list_splice_tail_init(&fiq->pending, &to_end);
2160                 while (forget_pending(fiq))
2161                         kfree(dequeue_forget(fiq, 1, NULL));
2162                 wake_up_all_locked(&fiq->waitq);
2163                 spin_unlock(&fiq->waitq.lock);
2164                 kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2165                 end_polls(fc);
2166                 wake_up_all(&fc->blocked_waitq);
2167                 spin_unlock(&fc->lock);
2168
2169                 end_requests(fc, &to_end);
2170         } else {
2171                 spin_unlock(&fc->lock);
2172         }
2173 }
2174 EXPORT_SYMBOL_GPL(fuse_abort_conn);
2175
2176 void fuse_wait_aborted(struct fuse_conn *fc)
2177 {
2178         wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2179 }
2180
2181 int fuse_dev_release(struct inode *inode, struct file *file)
2182 {
2183         struct fuse_dev *fud = fuse_get_dev(file);
2184
2185         if (fud) {
2186                 struct fuse_conn *fc = fud->fc;
2187                 struct fuse_pqueue *fpq = &fud->pq;
2188                 LIST_HEAD(to_end);
2189
2190                 spin_lock(&fpq->lock);
2191                 WARN_ON(!list_empty(&fpq->io));
2192                 list_splice_init(&fpq->processing, &to_end);
2193                 spin_unlock(&fpq->lock);
2194
2195                 end_requests(fc, &to_end);
2196
2197                 /* Are we the last open device? */
2198                 if (atomic_dec_and_test(&fc->dev_count)) {
2199                         WARN_ON(fc->iq.fasync != NULL);
2200                         fuse_abort_conn(fc, false);
2201                 }
2202                 fuse_dev_free(fud);
2203         }
2204         return 0;
2205 }
2206 EXPORT_SYMBOL_GPL(fuse_dev_release);
2207
2208 static int fuse_dev_fasync(int fd, struct file *file, int on)
2209 {
2210         struct fuse_dev *fud = fuse_get_dev(file);
2211
2212         if (!fud)
2213                 return -EPERM;
2214
2215         /* No locking - fasync_helper does its own locking */
2216         return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2217 }
2218
2219 static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2220 {
2221         struct fuse_dev *fud;
2222
2223         if (new->private_data)
2224                 return -EINVAL;
2225
2226         fud = fuse_dev_alloc(fc);
2227         if (!fud)
2228                 return -ENOMEM;
2229
2230         new->private_data = fud;
2231         atomic_inc(&fc->dev_count);
2232
2233         return 0;
2234 }
2235
2236 static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2237                            unsigned long arg)
2238 {
2239         int err = -ENOTTY;
2240
2241         if (cmd == FUSE_DEV_IOC_CLONE) {
2242                 int oldfd;
2243
2244                 err = -EFAULT;
2245                 if (!get_user(oldfd, (__u32 __user *) arg)) {
2246                         struct file *old = fget(oldfd);
2247
2248                         err = -EINVAL;
2249                         if (old) {
2250                                 struct fuse_dev *fud = NULL;
2251
2252                                 /*
2253                                  * Check against file->f_op because CUSE
2254                                  * uses the same ioctl handler.
2255                                  */
2256                                 if (old->f_op == file->f_op &&
2257                                     old->f_cred->user_ns == file->f_cred->user_ns)
2258                                         fud = fuse_get_dev(old);
2259
2260                                 if (fud) {
2261                                         mutex_lock(&fuse_mutex);
2262                                         err = fuse_device_clone(fud->fc, file);
2263                                         mutex_unlock(&fuse_mutex);
2264                                 }
2265                                 fput(old);
2266                         }
2267                 }
2268         }
2269         return err;
2270 }
2271
2272 const struct file_operations fuse_dev_operations = {
2273         .owner          = THIS_MODULE,
2274         .open           = fuse_dev_open,
2275         .llseek         = no_llseek,
2276         .read_iter      = fuse_dev_read,
2277         .splice_read    = fuse_dev_splice_read,
2278         .write_iter     = fuse_dev_write,
2279         .splice_write   = fuse_dev_splice_write,
2280         .poll           = fuse_dev_poll,
2281         .release        = fuse_dev_release,
2282         .fasync         = fuse_dev_fasync,
2283         .unlocked_ioctl = fuse_dev_ioctl,
2284         .compat_ioctl   = fuse_dev_ioctl,
2285 };
2286 EXPORT_SYMBOL_GPL(fuse_dev_operations);
2287
2288 static struct miscdevice fuse_miscdevice = {
2289         .minor = FUSE_MINOR,
2290         .name  = "fuse",
2291         .fops = &fuse_dev_operations,
2292 };
2293
2294 int __init fuse_dev_init(void)
2295 {
2296         int err = -ENOMEM;
2297         fuse_req_cachep = kmem_cache_create("fuse_request",
2298                                             sizeof(struct fuse_req),
2299                                             0, 0, NULL);
2300         if (!fuse_req_cachep)
2301                 goto out;
2302
2303         err = misc_register(&fuse_miscdevice);
2304         if (err)
2305                 goto out_cache_clean;
2306
2307         return 0;
2308
2309  out_cache_clean:
2310         kmem_cache_destroy(fuse_req_cachep);
2311  out:
2312         return err;
2313 }
2314
2315 void fuse_dev_cleanup(void)
2316 {
2317         misc_deregister(&fuse_miscdevice);
2318         kmem_cache_destroy(fuse_req_cachep);
2319 }