linux/fs/fuse/dev.c
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   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
  25MODULE_ALIAS_MISCDEV(FUSE_MINOR);
  26MODULE_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
  32static struct kmem_cache *fuse_req_cachep;
  33
  34static 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
  43static void fuse_request_init(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}
  51
  52static struct fuse_req *fuse_request_alloc(gfp_t flags)
  53{
  54        struct fuse_req *req = kmem_cache_zalloc(fuse_req_cachep, flags);
  55        if (req)
  56                fuse_request_init(req);
  57
  58        return req;
  59}
  60
  61static void fuse_request_free(struct fuse_req *req)
  62{
  63        kmem_cache_free(fuse_req_cachep, req);
  64}
  65
  66static void __fuse_get_request(struct fuse_req *req)
  67{
  68        refcount_inc(&req->count);
  69}
  70
  71/* Must be called with > 1 refcount */
  72static void __fuse_put_request(struct fuse_req *req)
  73{
  74        refcount_dec(&req->count);
  75}
  76
  77void fuse_set_initialized(struct fuse_conn *fc)
  78{
  79        /* Make sure stores before this are seen on another CPU */
  80        smp_wmb();
  81        fc->initialized = 1;
  82}
  83
  84static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
  85{
  86        return !fc->initialized || (for_background && fc->blocked);
  87}
  88
  89static void fuse_drop_waiting(struct fuse_conn *fc)
  90{
  91        /*
  92         * lockess check of fc->connected is okay, because atomic_dec_and_test()
  93         * provides a memory barrier mached with the one in fuse_wait_aborted()
  94         * to ensure no wake-up is missed.
  95         */
  96        if (atomic_dec_and_test(&fc->num_waiting) &&
  97            !READ_ONCE(fc->connected)) {
  98                /* wake up aborters */
  99                wake_up_all(&fc->blocked_waitq);
 100        }
 101}
 102
 103static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req);
 104
 105static struct fuse_req *fuse_get_req(struct fuse_conn *fc, bool for_background)
 106{
 107        struct fuse_req *req;
 108        int err;
 109        atomic_inc(&fc->num_waiting);
 110
 111        if (fuse_block_alloc(fc, for_background)) {
 112                err = -EINTR;
 113                if (wait_event_killable_exclusive(fc->blocked_waitq,
 114                                !fuse_block_alloc(fc, for_background)))
 115                        goto out;
 116        }
 117        /* Matches smp_wmb() in fuse_set_initialized() */
 118        smp_rmb();
 119
 120        err = -ENOTCONN;
 121        if (!fc->connected)
 122                goto out;
 123
 124        err = -ECONNREFUSED;
 125        if (fc->conn_error)
 126                goto out;
 127
 128        req = fuse_request_alloc(GFP_KERNEL);
 129        err = -ENOMEM;
 130        if (!req) {
 131                if (for_background)
 132                        wake_up(&fc->blocked_waitq);
 133                goto out;
 134        }
 135
 136        req->in.h.uid = from_kuid(fc->user_ns, current_fsuid());
 137        req->in.h.gid = from_kgid(fc->user_ns, current_fsgid());
 138        req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 139
 140        __set_bit(FR_WAITING, &req->flags);
 141        if (for_background)
 142                __set_bit(FR_BACKGROUND, &req->flags);
 143
 144        if (unlikely(req->in.h.uid == ((uid_t)-1) ||
 145                     req->in.h.gid == ((gid_t)-1))) {
 146                fuse_put_request(fc, req);
 147                return ERR_PTR(-EOVERFLOW);
 148        }
 149        return req;
 150
 151 out:
 152        fuse_drop_waiting(fc);
 153        return ERR_PTR(err);
 154}
 155
 156static void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 157{
 158        if (refcount_dec_and_test(&req->count)) {
 159                if (test_bit(FR_BACKGROUND, &req->flags)) {
 160                        /*
 161                         * We get here in the unlikely case that a background
 162                         * request was allocated but not sent
 163                         */
 164                        spin_lock(&fc->bg_lock);
 165                        if (!fc->blocked)
 166                                wake_up(&fc->blocked_waitq);
 167                        spin_unlock(&fc->bg_lock);
 168                }
 169
 170                if (test_bit(FR_WAITING, &req->flags)) {
 171                        __clear_bit(FR_WAITING, &req->flags);
 172                        fuse_drop_waiting(fc);
 173                }
 174
 175                fuse_request_free(req);
 176        }
 177}
 178
 179unsigned int fuse_len_args(unsigned int numargs, struct fuse_arg *args)
 180{
 181        unsigned nbytes = 0;
 182        unsigned i;
 183
 184        for (i = 0; i < numargs; i++)
 185                nbytes += args[i].size;
 186
 187        return nbytes;
 188}
 189EXPORT_SYMBOL_GPL(fuse_len_args);
 190
 191u64 fuse_get_unique(struct fuse_iqueue *fiq)
 192{
 193        fiq->reqctr += FUSE_REQ_ID_STEP;
 194        return fiq->reqctr;
 195}
 196EXPORT_SYMBOL_GPL(fuse_get_unique);
 197
 198static unsigned int fuse_req_hash(u64 unique)
 199{
 200        return hash_long(unique & ~FUSE_INT_REQ_BIT, FUSE_PQ_HASH_BITS);
 201}
 202
 203/**
 204 * A new request is available, wake fiq->waitq
 205 */
 206static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq)
 207__releases(fiq->lock)
 208{
 209        wake_up(&fiq->waitq);
 210        kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
 211        spin_unlock(&fiq->lock);
 212}
 213
 214const struct fuse_iqueue_ops fuse_dev_fiq_ops = {
 215        .wake_forget_and_unlock         = fuse_dev_wake_and_unlock,
 216        .wake_interrupt_and_unlock      = fuse_dev_wake_and_unlock,
 217        .wake_pending_and_unlock        = fuse_dev_wake_and_unlock,
 218};
 219EXPORT_SYMBOL_GPL(fuse_dev_fiq_ops);
 220
 221static void queue_request_and_unlock(struct fuse_iqueue *fiq,
 222                                     struct fuse_req *req)
 223__releases(fiq->lock)
 224{
 225        req->in.h.len = sizeof(struct fuse_in_header) +
 226                fuse_len_args(req->args->in_numargs,
 227                              (struct fuse_arg *) req->args->in_args);
 228        list_add_tail(&req->list, &fiq->pending);
 229        fiq->ops->wake_pending_and_unlock(fiq);
 230}
 231
 232void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 233                       u64 nodeid, u64 nlookup)
 234{
 235        struct fuse_iqueue *fiq = &fc->iq;
 236
 237        forget->forget_one.nodeid = nodeid;
 238        forget->forget_one.nlookup = nlookup;
 239
 240        spin_lock(&fiq->lock);
 241        if (fiq->connected) {
 242                fiq->forget_list_tail->next = forget;
 243                fiq->forget_list_tail = forget;
 244                fiq->ops->wake_forget_and_unlock(fiq);
 245        } else {
 246                kfree(forget);
 247                spin_unlock(&fiq->lock);
 248        }
 249}
 250
 251static void flush_bg_queue(struct fuse_conn *fc)
 252{
 253        struct fuse_iqueue *fiq = &fc->iq;
 254
 255        while (fc->active_background < fc->max_background &&
 256               !list_empty(&fc->bg_queue)) {
 257                struct fuse_req *req;
 258
 259                req = list_first_entry(&fc->bg_queue, struct fuse_req, list);
 260                list_del(&req->list);
 261                fc->active_background++;
 262                spin_lock(&fiq->lock);
 263                req->in.h.unique = fuse_get_unique(fiq);
 264                queue_request_and_unlock(fiq, req);
 265        }
 266}
 267
 268/*
 269 * This function is called when a request is finished.  Either a reply
 270 * has arrived or it was aborted (and not yet sent) or some error
 271 * occurred during communication with userspace, or the device file
 272 * was closed.  The requester thread is woken up (if still waiting),
 273 * the 'end' callback is called if given, else the reference to the
 274 * request is released
 275 */
 276void fuse_request_end(struct fuse_conn *fc, struct fuse_req *req)
 277{
 278        struct fuse_iqueue *fiq = &fc->iq;
 279
 280        if (test_and_set_bit(FR_FINISHED, &req->flags))
 281                goto put_request;
 282
 283        /*
 284         * test_and_set_bit() implies smp_mb() between bit
 285         * changing and below intr_entry check. Pairs with
 286         * smp_mb() from queue_interrupt().
 287         */
 288        if (!list_empty(&req->intr_entry)) {
 289                spin_lock(&fiq->lock);
 290                list_del_init(&req->intr_entry);
 291                spin_unlock(&fiq->lock);
 292        }
 293        WARN_ON(test_bit(FR_PENDING, &req->flags));
 294        WARN_ON(test_bit(FR_SENT, &req->flags));
 295        if (test_bit(FR_BACKGROUND, &req->flags)) {
 296                spin_lock(&fc->bg_lock);
 297                clear_bit(FR_BACKGROUND, &req->flags);
 298                if (fc->num_background == fc->max_background) {
 299                        fc->blocked = 0;
 300                        wake_up(&fc->blocked_waitq);
 301                } else if (!fc->blocked) {
 302                        /*
 303                         * Wake up next waiter, if any.  It's okay to use
 304                         * waitqueue_active(), as we've already synced up
 305                         * fc->blocked with waiters with the wake_up() call
 306                         * above.
 307                         */
 308                        if (waitqueue_active(&fc->blocked_waitq))
 309                                wake_up(&fc->blocked_waitq);
 310                }
 311
 312                if (fc->num_background == fc->congestion_threshold && fc->sb) {
 313                        clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 314                        clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 315                }
 316                fc->num_background--;
 317                fc->active_background--;
 318                flush_bg_queue(fc);
 319                spin_unlock(&fc->bg_lock);
 320        } else {
 321                /* Wake up waiter sleeping in request_wait_answer() */
 322                wake_up(&req->waitq);
 323        }
 324
 325        if (test_bit(FR_ASYNC, &req->flags))
 326                req->args->end(fc, req->args, req->out.h.error);
 327put_request:
 328        fuse_put_request(fc, req);
 329}
 330EXPORT_SYMBOL_GPL(fuse_request_end);
 331
 332static int queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
 333{
 334        spin_lock(&fiq->lock);
 335        /* Check for we've sent request to interrupt this req */
 336        if (unlikely(!test_bit(FR_INTERRUPTED, &req->flags))) {
 337                spin_unlock(&fiq->lock);
 338                return -EINVAL;
 339        }
 340
 341        if (list_empty(&req->intr_entry)) {
 342                list_add_tail(&req->intr_entry, &fiq->interrupts);
 343                /*
 344                 * Pairs with smp_mb() implied by test_and_set_bit()
 345                 * from request_end().
 346                 */
 347                smp_mb();
 348                if (test_bit(FR_FINISHED, &req->flags)) {
 349                        list_del_init(&req->intr_entry);
 350                        spin_unlock(&fiq->lock);
 351                        return 0;
 352                }
 353                fiq->ops->wake_interrupt_and_unlock(fiq);
 354        } else {
 355                spin_unlock(&fiq->lock);
 356        }
 357        return 0;
 358}
 359
 360static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 361{
 362        struct fuse_iqueue *fiq = &fc->iq;
 363        int err;
 364
 365        if (!fc->no_interrupt) {
 366                /* Any signal may interrupt this */
 367                err = wait_event_interruptible(req->waitq,
 368                                        test_bit(FR_FINISHED, &req->flags));
 369                if (!err)
 370                        return;
 371
 372                set_bit(FR_INTERRUPTED, &req->flags);
 373                /* matches barrier in fuse_dev_do_read() */
 374                smp_mb__after_atomic();
 375                if (test_bit(FR_SENT, &req->flags))
 376                        queue_interrupt(fiq, req);
 377        }
 378
 379        if (!test_bit(FR_FORCE, &req->flags)) {
 380                /* Only fatal signals may interrupt this */
 381                err = wait_event_killable(req->waitq,
 382                                        test_bit(FR_FINISHED, &req->flags));
 383                if (!err)
 384                        return;
 385
 386                spin_lock(&fiq->lock);
 387                /* Request is not yet in userspace, bail out */
 388                if (test_bit(FR_PENDING, &req->flags)) {
 389                        list_del(&req->list);
 390                        spin_unlock(&fiq->lock);
 391                        __fuse_put_request(req);
 392                        req->out.h.error = -EINTR;
 393                        return;
 394                }
 395                spin_unlock(&fiq->lock);
 396        }
 397
 398        /*
 399         * Either request is already in userspace, or it was forced.
 400         * Wait it out.
 401         */
 402        wait_event(req->waitq, test_bit(FR_FINISHED, &req->flags));
 403}
 404
 405static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 406{
 407        struct fuse_iqueue *fiq = &fc->iq;
 408
 409        BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
 410        spin_lock(&fiq->lock);
 411        if (!fiq->connected) {
 412                spin_unlock(&fiq->lock);
 413                req->out.h.error = -ENOTCONN;
 414        } else {
 415                req->in.h.unique = fuse_get_unique(fiq);
 416                /* acquire extra reference, since request is still needed
 417                   after fuse_request_end() */
 418                __fuse_get_request(req);
 419                queue_request_and_unlock(fiq, req);
 420
 421                request_wait_answer(fc, req);
 422                /* Pairs with smp_wmb() in fuse_request_end() */
 423                smp_rmb();
 424        }
 425}
 426
 427static void fuse_adjust_compat(struct fuse_conn *fc, struct fuse_args *args)
 428{
 429        if (fc->minor < 4 && args->opcode == FUSE_STATFS)
 430                args->out_args[0].size = FUSE_COMPAT_STATFS_SIZE;
 431
 432        if (fc->minor < 9) {
 433                switch (args->opcode) {
 434                case FUSE_LOOKUP:
 435                case FUSE_CREATE:
 436                case FUSE_MKNOD:
 437                case FUSE_MKDIR:
 438                case FUSE_SYMLINK:
 439                case FUSE_LINK:
 440                        args->out_args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 441                        break;
 442                case FUSE_GETATTR:
 443                case FUSE_SETATTR:
 444                        args->out_args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 445                        break;
 446                }
 447        }
 448        if (fc->minor < 12) {
 449                switch (args->opcode) {
 450                case FUSE_CREATE:
 451                        args->in_args[0].size = sizeof(struct fuse_open_in);
 452                        break;
 453                case FUSE_MKNOD:
 454                        args->in_args[0].size = FUSE_COMPAT_MKNOD_IN_SIZE;
 455                        break;
 456                }
 457        }
 458}
 459
 460static void fuse_force_creds(struct fuse_conn *fc, struct fuse_req *req)
 461{
 462        req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid());
 463        req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid());
 464        req->in.h.pid = pid_nr_ns(task_pid(current), fc->pid_ns);
 465}
 466
 467static void fuse_args_to_req(struct fuse_req *req, struct fuse_args *args)
 468{
 469        req->in.h.opcode = args->opcode;
 470        req->in.h.nodeid = args->nodeid;
 471        req->args = args;
 472        if (args->end)
 473                __set_bit(FR_ASYNC, &req->flags);
 474}
 475
 476ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
 477{
 478        struct fuse_req *req;
 479        ssize_t ret;
 480
 481        if (args->force) {
 482                atomic_inc(&fc->num_waiting);
 483                req = fuse_request_alloc(GFP_KERNEL | __GFP_NOFAIL);
 484
 485                if (!args->nocreds)
 486                        fuse_force_creds(fc, req);
 487
 488                __set_bit(FR_WAITING, &req->flags);
 489                __set_bit(FR_FORCE, &req->flags);
 490        } else {
 491                WARN_ON(args->nocreds);
 492                req = fuse_get_req(fc, false);
 493                if (IS_ERR(req))
 494                        return PTR_ERR(req);
 495        }
 496
 497        /* Needs to be done after fuse_get_req() so that fc->minor is valid */
 498        fuse_adjust_compat(fc, args);
 499        fuse_args_to_req(req, args);
 500
 501        if (!args->noreply)
 502                __set_bit(FR_ISREPLY, &req->flags);
 503        __fuse_request_send(fc, req);
 504        ret = req->out.h.error;
 505        if (!ret && args->out_argvar) {
 506                BUG_ON(args->out_numargs == 0);
 507                ret = args->out_args[args->out_numargs - 1].size;
 508        }
 509        fuse_put_request(fc, req);
 510
 511        return ret;
 512}
 513
 514static bool fuse_request_queue_background(struct fuse_conn *fc,
 515                                          struct fuse_req *req)
 516{
 517        bool queued = false;
 518
 519        WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
 520        if (!test_bit(FR_WAITING, &req->flags)) {
 521                __set_bit(FR_WAITING, &req->flags);
 522                atomic_inc(&fc->num_waiting);
 523        }
 524        __set_bit(FR_ISREPLY, &req->flags);
 525        spin_lock(&fc->bg_lock);
 526        if (likely(fc->connected)) {
 527                fc->num_background++;
 528                if (fc->num_background == fc->max_background)
 529                        fc->blocked = 1;
 530                if (fc->num_background == fc->congestion_threshold && fc->sb) {
 531                        set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 532                        set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 533                }
 534                list_add_tail(&req->list, &fc->bg_queue);
 535                flush_bg_queue(fc);
 536                queued = true;
 537        }
 538        spin_unlock(&fc->bg_lock);
 539
 540        return queued;
 541}
 542
 543int fuse_simple_background(struct fuse_conn *fc, struct fuse_args *args,
 544                            gfp_t gfp_flags)
 545{
 546        struct fuse_req *req;
 547
 548        if (args->force) {
 549                WARN_ON(!args->nocreds);
 550                req = fuse_request_alloc(gfp_flags);
 551                if (!req)
 552                        return -ENOMEM;
 553                __set_bit(FR_BACKGROUND, &req->flags);
 554        } else {
 555                WARN_ON(args->nocreds);
 556                req = fuse_get_req(fc, true);
 557                if (IS_ERR(req))
 558                        return PTR_ERR(req);
 559        }
 560
 561        fuse_args_to_req(req, args);
 562
 563        if (!fuse_request_queue_background(fc, req)) {
 564                fuse_put_request(fc, req);
 565                return -ENOTCONN;
 566        }
 567
 568        return 0;
 569}
 570EXPORT_SYMBOL_GPL(fuse_simple_background);
 571
 572static int fuse_simple_notify_reply(struct fuse_conn *fc,
 573                                    struct fuse_args *args, u64 unique)
 574{
 575        struct fuse_req *req;
 576        struct fuse_iqueue *fiq = &fc->iq;
 577        int err = 0;
 578
 579        req = fuse_get_req(fc, false);
 580        if (IS_ERR(req))
 581                return PTR_ERR(req);
 582
 583        __clear_bit(FR_ISREPLY, &req->flags);
 584        req->in.h.unique = unique;
 585
 586        fuse_args_to_req(req, args);
 587
 588        spin_lock(&fiq->lock);
 589        if (fiq->connected) {
 590                queue_request_and_unlock(fiq, req);
 591        } else {
 592                err = -ENODEV;
 593                spin_unlock(&fiq->lock);
 594                fuse_put_request(fc, req);
 595        }
 596
 597        return err;
 598}
 599
 600/*
 601 * Lock the request.  Up to the next unlock_request() there mustn't be
 602 * anything that could cause a page-fault.  If the request was already
 603 * aborted bail out.
 604 */
 605static int lock_request(struct fuse_req *req)
 606{
 607        int err = 0;
 608        if (req) {
 609                spin_lock(&req->waitq.lock);
 610                if (test_bit(FR_ABORTED, &req->flags))
 611                        err = -ENOENT;
 612                else
 613                        set_bit(FR_LOCKED, &req->flags);
 614                spin_unlock(&req->waitq.lock);
 615        }
 616        return err;
 617}
 618
 619/*
 620 * Unlock request.  If it was aborted while locked, caller is responsible
 621 * for unlocking and ending the request.
 622 */
 623static int unlock_request(struct fuse_req *req)
 624{
 625        int err = 0;
 626        if (req) {
 627                spin_lock(&req->waitq.lock);
 628                if (test_bit(FR_ABORTED, &req->flags))
 629                        err = -ENOENT;
 630                else
 631                        clear_bit(FR_LOCKED, &req->flags);
 632                spin_unlock(&req->waitq.lock);
 633        }
 634        return err;
 635}
 636
 637struct fuse_copy_state {
 638        int write;
 639        struct fuse_req *req;
 640        struct iov_iter *iter;
 641        struct pipe_buffer *pipebufs;
 642        struct pipe_buffer *currbuf;
 643        struct pipe_inode_info *pipe;
 644        unsigned long nr_segs;
 645        struct page *pg;
 646        unsigned len;
 647        unsigned offset;
 648        unsigned move_pages:1;
 649};
 650
 651static void fuse_copy_init(struct fuse_copy_state *cs, int write,
 652                           struct iov_iter *iter)
 653{
 654        memset(cs, 0, sizeof(*cs));
 655        cs->write = write;
 656        cs->iter = iter;
 657}
 658
 659/* Unmap and put previous page of userspace buffer */
 660static void fuse_copy_finish(struct fuse_copy_state *cs)
 661{
 662        if (cs->currbuf) {
 663                struct pipe_buffer *buf = cs->currbuf;
 664
 665                if (cs->write)
 666                        buf->len = PAGE_SIZE - cs->len;
 667                cs->currbuf = NULL;
 668        } else if (cs->pg) {
 669                if (cs->write) {
 670                        flush_dcache_page(cs->pg);
 671                        set_page_dirty_lock(cs->pg);
 672                }
 673                put_page(cs->pg);
 674        }
 675        cs->pg = NULL;
 676}
 677
 678/*
 679 * Get another pagefull of userspace buffer, and map it to kernel
 680 * address space, and lock request
 681 */
 682static int fuse_copy_fill(struct fuse_copy_state *cs)
 683{
 684        struct page *page;
 685        int err;
 686
 687        err = unlock_request(cs->req);
 688        if (err)
 689                return err;
 690
 691        fuse_copy_finish(cs);
 692        if (cs->pipebufs) {
 693                struct pipe_buffer *buf = cs->pipebufs;
 694
 695                if (!cs->write) {
 696                        err = pipe_buf_confirm(cs->pipe, buf);
 697                        if (err)
 698                                return err;
 699
 700                        BUG_ON(!cs->nr_segs);
 701                        cs->currbuf = buf;
 702                        cs->pg = buf->page;
 703                        cs->offset = buf->offset;
 704                        cs->len = buf->len;
 705                        cs->pipebufs++;
 706                        cs->nr_segs--;
 707                } else {
 708                        if (cs->nr_segs == cs->pipe->buffers)
 709                                return -EIO;
 710
 711                        page = alloc_page(GFP_HIGHUSER);
 712                        if (!page)
 713                                return -ENOMEM;
 714
 715                        buf->page = page;
 716                        buf->offset = 0;
 717                        buf->len = 0;
 718
 719                        cs->currbuf = buf;
 720                        cs->pg = page;
 721                        cs->offset = 0;
 722                        cs->len = PAGE_SIZE;
 723                        cs->pipebufs++;
 724                        cs->nr_segs++;
 725                }
 726        } else {
 727                size_t off;
 728                err = iov_iter_get_pages(cs->iter, &page, PAGE_SIZE, 1, &off);
 729                if (err < 0)
 730                        return err;
 731                BUG_ON(!err);
 732                cs->len = err;
 733                cs->offset = off;
 734                cs->pg = page;
 735                iov_iter_advance(cs->iter, err);
 736        }
 737
 738        return lock_request(cs->req);
 739}
 740
 741/* Do as much copy to/from userspace buffer as we can */
 742static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 743{
 744        unsigned ncpy = min(*size, cs->len);
 745        if (val) {
 746                void *pgaddr = kmap_atomic(cs->pg);
 747                void *buf = pgaddr + cs->offset;
 748
 749                if (cs->write)
 750                        memcpy(buf, *val, ncpy);
 751                else
 752                        memcpy(*val, buf, ncpy);
 753
 754                kunmap_atomic(pgaddr);
 755                *val += ncpy;
 756        }
 757        *size -= ncpy;
 758        cs->len -= ncpy;
 759        cs->offset += ncpy;
 760        return ncpy;
 761}
 762
 763static int fuse_check_page(struct page *page)
 764{
 765        if (page_mapcount(page) ||
 766            page->mapping != NULL ||
 767            (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 768             ~(1 << PG_locked |
 769               1 << PG_referenced |
 770               1 << PG_uptodate |
 771               1 << PG_lru |
 772               1 << PG_active |
 773               1 << PG_reclaim |
 774               1 << PG_waiters))) {
 775                dump_page(page, "fuse: trying to steal weird page");
 776                return 1;
 777        }
 778        return 0;
 779}
 780
 781static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 782{
 783        int err;
 784        struct page *oldpage = *pagep;
 785        struct page *newpage;
 786        struct pipe_buffer *buf = cs->pipebufs;
 787
 788        err = unlock_request(cs->req);
 789        if (err)
 790                return err;
 791
 792        fuse_copy_finish(cs);
 793
 794        err = pipe_buf_confirm(cs->pipe, buf);
 795        if (err)
 796                return err;
 797
 798        BUG_ON(!cs->nr_segs);
 799        cs->currbuf = buf;
 800        cs->len = buf->len;
 801        cs->pipebufs++;
 802        cs->nr_segs--;
 803
 804        if (cs->len != PAGE_SIZE)
 805                goto out_fallback;
 806
 807        if (pipe_buf_steal(cs->pipe, buf) != 0)
 808                goto out_fallback;
 809
 810        newpage = buf->page;
 811
 812        if (!PageUptodate(newpage))
 813                SetPageUptodate(newpage);
 814
 815        ClearPageMappedToDisk(newpage);
 816
 817        if (fuse_check_page(newpage) != 0)
 818                goto out_fallback_unlock;
 819
 820        /*
 821         * This is a new and locked page, it shouldn't be mapped or
 822         * have any special flags on it
 823         */
 824        if (WARN_ON(page_mapped(oldpage)))
 825                goto out_fallback_unlock;
 826        if (WARN_ON(page_has_private(oldpage)))
 827                goto out_fallback_unlock;
 828        if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 829                goto out_fallback_unlock;
 830        if (WARN_ON(PageMlocked(oldpage)))
 831                goto out_fallback_unlock;
 832
 833        err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 834        if (err) {
 835                unlock_page(newpage);
 836                return err;
 837        }
 838
 839        get_page(newpage);
 840
 841        if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 842                lru_cache_add(newpage);
 843
 844        err = 0;
 845        spin_lock(&cs->req->waitq.lock);
 846        if (test_bit(FR_ABORTED, &cs->req->flags))
 847                err = -ENOENT;
 848        else
 849                *pagep = newpage;
 850        spin_unlock(&cs->req->waitq.lock);
 851
 852        if (err) {
 853                unlock_page(newpage);
 854                put_page(newpage);
 855                return err;
 856        }
 857
 858        unlock_page(oldpage);
 859        put_page(oldpage);
 860        cs->len = 0;
 861
 862        return 0;
 863
 864out_fallback_unlock:
 865        unlock_page(newpage);
 866out_fallback:
 867        cs->pg = buf->page;
 868        cs->offset = buf->offset;
 869
 870        err = lock_request(cs->req);
 871        if (err)
 872                return err;
 873
 874        return 1;
 875}
 876
 877static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 878                         unsigned offset, unsigned count)
 879{
 880        struct pipe_buffer *buf;
 881        int err;
 882
 883        if (cs->nr_segs == cs->pipe->buffers)
 884                return -EIO;
 885
 886        err = unlock_request(cs->req);
 887        if (err)
 888                return err;
 889
 890        fuse_copy_finish(cs);
 891
 892        buf = cs->pipebufs;
 893        get_page(page);
 894        buf->page = page;
 895        buf->offset = offset;
 896        buf->len = count;
 897
 898        cs->pipebufs++;
 899        cs->nr_segs++;
 900        cs->len = 0;
 901
 902        return 0;
 903}
 904
 905/*
 906 * Copy a page in the request to/from the userspace buffer.  Must be
 907 * done atomically
 908 */
 909static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 910                          unsigned offset, unsigned count, int zeroing)
 911{
 912        int err;
 913        struct page *page = *pagep;
 914
 915        if (page && zeroing && count < PAGE_SIZE)
 916                clear_highpage(page);
 917
 918        while (count) {
 919                if (cs->write && cs->pipebufs && page) {
 920                        return fuse_ref_page(cs, page, offset, count);
 921                } else if (!cs->len) {
 922                        if (cs->move_pages && page &&
 923                            offset == 0 && count == PAGE_SIZE) {
 924                                err = fuse_try_move_page(cs, pagep);
 925                                if (err <= 0)
 926                                        return err;
 927                        } else {
 928                                err = fuse_copy_fill(cs);
 929                                if (err)
 930                                        return err;
 931                        }
 932                }
 933                if (page) {
 934                        void *mapaddr = kmap_atomic(page);
 935                        void *buf = mapaddr + offset;
 936                        offset += fuse_copy_do(cs, &buf, &count);
 937                        kunmap_atomic(mapaddr);
 938                } else
 939                        offset += fuse_copy_do(cs, NULL, &count);
 940        }
 941        if (page && !cs->write)
 942                flush_dcache_page(page);
 943        return 0;
 944}
 945
 946/* Copy pages in the request to/from userspace buffer */
 947static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 948                           int zeroing)
 949{
 950        unsigned i;
 951        struct fuse_req *req = cs->req;
 952        struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
 953
 954
 955        for (i = 0; i < ap->num_pages && (nbytes || zeroing); i++) {
 956                int err;
 957                unsigned int offset = ap->descs[i].offset;
 958                unsigned int count = min(nbytes, ap->descs[i].length);
 959
 960                err = fuse_copy_page(cs, &ap->pages[i], offset, count, zeroing);
 961                if (err)
 962                        return err;
 963
 964                nbytes -= count;
 965        }
 966        return 0;
 967}
 968
 969/* Copy a single argument in the request to/from userspace buffer */
 970static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
 971{
 972        while (size) {
 973                if (!cs->len) {
 974                        int err = fuse_copy_fill(cs);
 975                        if (err)
 976                                return err;
 977                }
 978                fuse_copy_do(cs, &val, &size);
 979        }
 980        return 0;
 981}
 982
 983/* Copy request arguments to/from userspace buffer */
 984static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
 985                          unsigned argpages, struct fuse_arg *args,
 986                          int zeroing)
 987{
 988        int err = 0;
 989        unsigned i;
 990
 991        for (i = 0; !err && i < numargs; i++)  {
 992                struct fuse_arg *arg = &args[i];
 993                if (i == numargs - 1 && argpages)
 994                        err = fuse_copy_pages(cs, arg->size, zeroing);
 995                else
 996                        err = fuse_copy_one(cs, arg->value, arg->size);
 997        }
 998        return err;
 999}
1000
1001static int forget_pending(struct fuse_iqueue *fiq)
1002{
1003        return fiq->forget_list_head.next != NULL;
1004}
1005
1006static int request_pending(struct fuse_iqueue *fiq)
1007{
1008        return !list_empty(&fiq->pending) || !list_empty(&fiq->interrupts) ||
1009                forget_pending(fiq);
1010}
1011
1012/*
1013 * Transfer an interrupt request to userspace
1014 *
1015 * Unlike other requests this is assembled on demand, without a need
1016 * to allocate a separate fuse_req structure.
1017 *
1018 * Called with fiq->lock held, releases it
1019 */
1020static int fuse_read_interrupt(struct fuse_iqueue *fiq,
1021                               struct fuse_copy_state *cs,
1022                               size_t nbytes, struct fuse_req *req)
1023__releases(fiq->lock)
1024{
1025        struct fuse_in_header ih;
1026        struct fuse_interrupt_in arg;
1027        unsigned reqsize = sizeof(ih) + sizeof(arg);
1028        int err;
1029
1030        list_del_init(&req->intr_entry);
1031        memset(&ih, 0, sizeof(ih));
1032        memset(&arg, 0, sizeof(arg));
1033        ih.len = reqsize;
1034        ih.opcode = FUSE_INTERRUPT;
1035        ih.unique = (req->in.h.unique | FUSE_INT_REQ_BIT);
1036        arg.unique = req->in.h.unique;
1037
1038        spin_unlock(&fiq->lock);
1039        if (nbytes < reqsize)
1040                return -EINVAL;
1041
1042        err = fuse_copy_one(cs, &ih, sizeof(ih));
1043        if (!err)
1044                err = fuse_copy_one(cs, &arg, sizeof(arg));
1045        fuse_copy_finish(cs);
1046
1047        return err ? err : reqsize;
1048}
1049
1050struct fuse_forget_link *fuse_dequeue_forget(struct fuse_iqueue *fiq,
1051                                             unsigned int max,
1052                                             unsigned int *countp)
1053{
1054        struct fuse_forget_link *head = fiq->forget_list_head.next;
1055        struct fuse_forget_link **newhead = &head;
1056        unsigned count;
1057
1058        for (count = 0; *newhead != NULL && count < max; count++)
1059                newhead = &(*newhead)->next;
1060
1061        fiq->forget_list_head.next = *newhead;
1062        *newhead = NULL;
1063        if (fiq->forget_list_head.next == NULL)
1064                fiq->forget_list_tail = &fiq->forget_list_head;
1065
1066        if (countp != NULL)
1067                *countp = count;
1068
1069        return head;
1070}
1071EXPORT_SYMBOL(fuse_dequeue_forget);
1072
1073static int fuse_read_single_forget(struct fuse_iqueue *fiq,
1074                                   struct fuse_copy_state *cs,
1075                                   size_t nbytes)
1076__releases(fiq->lock)
1077{
1078        int err;
1079        struct fuse_forget_link *forget = fuse_dequeue_forget(fiq, 1, NULL);
1080        struct fuse_forget_in arg = {
1081                .nlookup = forget->forget_one.nlookup,
1082        };
1083        struct fuse_in_header ih = {
1084                .opcode = FUSE_FORGET,
1085                .nodeid = forget->forget_one.nodeid,
1086                .unique = fuse_get_unique(fiq),
1087                .len = sizeof(ih) + sizeof(arg),
1088        };
1089
1090        spin_unlock(&fiq->lock);
1091        kfree(forget);
1092        if (nbytes < ih.len)
1093                return -EINVAL;
1094
1095        err = fuse_copy_one(cs, &ih, sizeof(ih));
1096        if (!err)
1097                err = fuse_copy_one(cs, &arg, sizeof(arg));
1098        fuse_copy_finish(cs);
1099
1100        if (err)
1101                return err;
1102
1103        return ih.len;
1104}
1105
1106static int fuse_read_batch_forget(struct fuse_iqueue *fiq,
1107                                   struct fuse_copy_state *cs, size_t nbytes)
1108__releases(fiq->lock)
1109{
1110        int err;
1111        unsigned max_forgets;
1112        unsigned count;
1113        struct fuse_forget_link *head;
1114        struct fuse_batch_forget_in arg = { .count = 0 };
1115        struct fuse_in_header ih = {
1116                .opcode = FUSE_BATCH_FORGET,
1117                .unique = fuse_get_unique(fiq),
1118                .len = sizeof(ih) + sizeof(arg),
1119        };
1120
1121        if (nbytes < ih.len) {
1122                spin_unlock(&fiq->lock);
1123                return -EINVAL;
1124        }
1125
1126        max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1127        head = fuse_dequeue_forget(fiq, max_forgets, &count);
1128        spin_unlock(&fiq->lock);
1129
1130        arg.count = count;
1131        ih.len += count * sizeof(struct fuse_forget_one);
1132        err = fuse_copy_one(cs, &ih, sizeof(ih));
1133        if (!err)
1134                err = fuse_copy_one(cs, &arg, sizeof(arg));
1135
1136        while (head) {
1137                struct fuse_forget_link *forget = head;
1138
1139                if (!err) {
1140                        err = fuse_copy_one(cs, &forget->forget_one,
1141                                            sizeof(forget->forget_one));
1142                }
1143                head = forget->next;
1144                kfree(forget);
1145        }
1146
1147        fuse_copy_finish(cs);
1148
1149        if (err)
1150                return err;
1151
1152        return ih.len;
1153}
1154
1155static int fuse_read_forget(struct fuse_conn *fc, struct fuse_iqueue *fiq,
1156                            struct fuse_copy_state *cs,
1157                            size_t nbytes)
1158__releases(fiq->lock)
1159{
1160        if (fc->minor < 16 || fiq->forget_list_head.next->next == NULL)
1161                return fuse_read_single_forget(fiq, cs, nbytes);
1162        else
1163                return fuse_read_batch_forget(fiq, cs, nbytes);
1164}
1165
1166/*
1167 * Read a single request into the userspace filesystem's buffer.  This
1168 * function waits until a request is available, then removes it from
1169 * the pending list and copies request data to userspace buffer.  If
1170 * no reply is needed (FORGET) or request has been aborted or there
1171 * was an error during the copying then it's finished by calling
1172 * fuse_request_end().  Otherwise add it to the processing list, and set
1173 * the 'sent' flag.
1174 */
1175static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file,
1176                                struct fuse_copy_state *cs, size_t nbytes)
1177{
1178        ssize_t err;
1179        struct fuse_conn *fc = fud->fc;
1180        struct fuse_iqueue *fiq = &fc->iq;
1181        struct fuse_pqueue *fpq = &fud->pq;
1182        struct fuse_req *req;
1183        struct fuse_args *args;
1184        unsigned reqsize;
1185        unsigned int hash;
1186
1187        /*
1188         * Require sane minimum read buffer - that has capacity for fixed part
1189         * of any request header + negotiated max_write room for data.
1190         *
1191         * Historically libfuse reserves 4K for fixed header room, but e.g.
1192         * GlusterFS reserves only 80 bytes
1193         *
1194         *      = `sizeof(fuse_in_header) + sizeof(fuse_write_in)`
1195         *
1196         * which is the absolute minimum any sane filesystem should be using
1197         * for header room.
1198         */
1199        if (nbytes < max_t(size_t, FUSE_MIN_READ_BUFFER,
1200                           sizeof(struct fuse_in_header) +
1201                           sizeof(struct fuse_write_in) +
1202                           fc->max_write))
1203                return -EINVAL;
1204
1205 restart:
1206        for (;;) {
1207                spin_lock(&fiq->lock);
1208                if (!fiq->connected || request_pending(fiq))
1209                        break;
1210                spin_unlock(&fiq->lock);
1211
1212                if (file->f_flags & O_NONBLOCK)
1213                        return -EAGAIN;
1214                err = wait_event_interruptible_exclusive(fiq->waitq,
1215                                !fiq->connected || request_pending(fiq));
1216                if (err)
1217                        return err;
1218        }
1219
1220        if (!fiq->connected) {
1221                err = fc->aborted ? -ECONNABORTED : -ENODEV;
1222                goto err_unlock;
1223        }
1224
1225        if (!list_empty(&fiq->interrupts)) {
1226                req = list_entry(fiq->interrupts.next, struct fuse_req,
1227                                 intr_entry);
1228                return fuse_read_interrupt(fiq, cs, nbytes, req);
1229        }
1230
1231        if (forget_pending(fiq)) {
1232                if (list_empty(&fiq->pending) || fiq->forget_batch-- > 0)
1233                        return fuse_read_forget(fc, fiq, cs, nbytes);
1234
1235                if (fiq->forget_batch <= -8)
1236                        fiq->forget_batch = 16;
1237        }
1238
1239        req = list_entry(fiq->pending.next, struct fuse_req, list);
1240        clear_bit(FR_PENDING, &req->flags);
1241        list_del_init(&req->list);
1242        spin_unlock(&fiq->lock);
1243
1244        args = req->args;
1245        reqsize = req->in.h.len;
1246
1247        /* If request is too large, reply with an error and restart the read */
1248        if (nbytes < reqsize) {
1249                req->out.h.error = -EIO;
1250                /* SETXATTR is special, since it may contain too large data */
1251                if (args->opcode == FUSE_SETXATTR)
1252                        req->out.h.error = -E2BIG;
1253                fuse_request_end(fc, req);
1254                goto restart;
1255        }
1256        spin_lock(&fpq->lock);
1257        list_add(&req->list, &fpq->io);
1258        spin_unlock(&fpq->lock);
1259        cs->req = req;
1260        err = fuse_copy_one(cs, &req->in.h, sizeof(req->in.h));
1261        if (!err)
1262                err = fuse_copy_args(cs, args->in_numargs, args->in_pages,
1263                                     (struct fuse_arg *) args->in_args, 0);
1264        fuse_copy_finish(cs);
1265        spin_lock(&fpq->lock);
1266        clear_bit(FR_LOCKED, &req->flags);
1267        if (!fpq->connected) {
1268                err = fc->aborted ? -ECONNABORTED : -ENODEV;
1269                goto out_end;
1270        }
1271        if (err) {
1272                req->out.h.error = -EIO;
1273                goto out_end;
1274        }
1275        if (!test_bit(FR_ISREPLY, &req->flags)) {
1276                err = reqsize;
1277                goto out_end;
1278        }
1279        hash = fuse_req_hash(req->in.h.unique);
1280        list_move_tail(&req->list, &fpq->processing[hash]);
1281        __fuse_get_request(req);
1282        set_bit(FR_SENT, &req->flags);
1283        spin_unlock(&fpq->lock);
1284        /* matches barrier in request_wait_answer() */
1285        smp_mb__after_atomic();
1286        if (test_bit(FR_INTERRUPTED, &req->flags))
1287                queue_interrupt(fiq, req);
1288        fuse_put_request(fc, req);
1289
1290        return reqsize;
1291
1292out_end:
1293        if (!test_bit(FR_PRIVATE, &req->flags))
1294                list_del_init(&req->list);
1295        spin_unlock(&fpq->lock);
1296        fuse_request_end(fc, req);
1297        return err;
1298
1299 err_unlock:
1300        spin_unlock(&fiq->lock);
1301        return err;
1302}
1303
1304static int fuse_dev_open(struct inode *inode, struct file *file)
1305{
1306        /*
1307         * The fuse device's file's private_data is used to hold
1308         * the fuse_conn(ection) when it is mounted, and is used to
1309         * keep track of whether the file has been mounted already.
1310         */
1311        file->private_data = NULL;
1312        return 0;
1313}
1314
1315static ssize_t fuse_dev_read(struct kiocb *iocb, struct iov_iter *to)
1316{
1317        struct fuse_copy_state cs;
1318        struct file *file = iocb->ki_filp;
1319        struct fuse_dev *fud = fuse_get_dev(file);
1320
1321        if (!fud)
1322                return -EPERM;
1323
1324        if (!iter_is_iovec(to))
1325                return -EINVAL;
1326
1327        fuse_copy_init(&cs, 1, to);
1328
1329        return fuse_dev_do_read(fud, file, &cs, iov_iter_count(to));
1330}
1331
1332static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1333                                    struct pipe_inode_info *pipe,
1334                                    size_t len, unsigned int flags)
1335{
1336        int total, ret;
1337        int page_nr = 0;
1338        struct pipe_buffer *bufs;
1339        struct fuse_copy_state cs;
1340        struct fuse_dev *fud = fuse_get_dev(in);
1341
1342        if (!fud)
1343                return -EPERM;
1344
1345        bufs = kvmalloc_array(pipe->buffers, sizeof(struct pipe_buffer),
1346                              GFP_KERNEL);
1347        if (!bufs)
1348                return -ENOMEM;
1349
1350        fuse_copy_init(&cs, 1, NULL);
1351        cs.pipebufs = bufs;
1352        cs.pipe = pipe;
1353        ret = fuse_dev_do_read(fud, in, &cs, len);
1354        if (ret < 0)
1355                goto out;
1356
1357        if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1358                ret = -EIO;
1359                goto out;
1360        }
1361
1362        for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
1363                /*
1364                 * Need to be careful about this.  Having buf->ops in module
1365                 * code can Oops if the buffer persists after module unload.
1366                 */
1367                bufs[page_nr].ops = &nosteal_pipe_buf_ops;
1368                bufs[page_nr].flags = 0;
1369                ret = add_to_pipe(pipe, &bufs[page_nr++]);
1370                if (unlikely(ret < 0))
1371                        break;
1372        }
1373        if (total)
1374                ret = total;
1375out:
1376        for (; page_nr < cs.nr_segs; page_nr++)
1377                put_page(bufs[page_nr].page);
1378
1379        kvfree(bufs);
1380        return ret;
1381}
1382
1383static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1384                            struct fuse_copy_state *cs)
1385{
1386        struct fuse_notify_poll_wakeup_out outarg;
1387        int err = -EINVAL;
1388
1389        if (size != sizeof(outarg))
1390                goto err;
1391
1392        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1393        if (err)
1394                goto err;
1395
1396        fuse_copy_finish(cs);
1397        return fuse_notify_poll_wakeup(fc, &outarg);
1398
1399err:
1400        fuse_copy_finish(cs);
1401        return err;
1402}
1403
1404static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1405                                   struct fuse_copy_state *cs)
1406{
1407        struct fuse_notify_inval_inode_out outarg;
1408        int err = -EINVAL;
1409
1410        if (size != sizeof(outarg))
1411                goto err;
1412
1413        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1414        if (err)
1415                goto err;
1416        fuse_copy_finish(cs);
1417
1418        down_read(&fc->killsb);
1419        err = -ENOENT;
1420        if (fc->sb) {
1421                err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1422                                               outarg.off, outarg.len);
1423        }
1424        up_read(&fc->killsb);
1425        return err;
1426
1427err:
1428        fuse_copy_finish(cs);
1429        return err;
1430}
1431
1432static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1433                                   struct fuse_copy_state *cs)
1434{
1435        struct fuse_notify_inval_entry_out outarg;
1436        int err = -ENOMEM;
1437        char *buf;
1438        struct qstr name;
1439
1440        buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1441        if (!buf)
1442                goto err;
1443
1444        err = -EINVAL;
1445        if (size < sizeof(outarg))
1446                goto err;
1447
1448        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1449        if (err)
1450                goto err;
1451
1452        err = -ENAMETOOLONG;
1453        if (outarg.namelen > FUSE_NAME_MAX)
1454                goto err;
1455
1456        err = -EINVAL;
1457        if (size != sizeof(outarg) + outarg.namelen + 1)
1458                goto err;
1459
1460        name.name = buf;
1461        name.len = outarg.namelen;
1462        err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1463        if (err)
1464                goto err;
1465        fuse_copy_finish(cs);
1466        buf[outarg.namelen] = 0;
1467
1468        down_read(&fc->killsb);
1469        err = -ENOENT;
1470        if (fc->sb)
1471                err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1472        up_read(&fc->killsb);
1473        kfree(buf);
1474        return err;
1475
1476err:
1477        kfree(buf);
1478        fuse_copy_finish(cs);
1479        return err;
1480}
1481
1482static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1483                              struct fuse_copy_state *cs)
1484{
1485        struct fuse_notify_delete_out outarg;
1486        int err = -ENOMEM;
1487        char *buf;
1488        struct qstr name;
1489
1490        buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1491        if (!buf)
1492                goto err;
1493
1494        err = -EINVAL;
1495        if (size < sizeof(outarg))
1496                goto err;
1497
1498        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1499        if (err)
1500                goto err;
1501
1502        err = -ENAMETOOLONG;
1503        if (outarg.namelen > FUSE_NAME_MAX)
1504                goto err;
1505
1506        err = -EINVAL;
1507        if (size != sizeof(outarg) + outarg.namelen + 1)
1508                goto err;
1509
1510        name.name = buf;
1511        name.len = outarg.namelen;
1512        err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1513        if (err)
1514                goto err;
1515        fuse_copy_finish(cs);
1516        buf[outarg.namelen] = 0;
1517
1518        down_read(&fc->killsb);
1519        err = -ENOENT;
1520        if (fc->sb)
1521                err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1522                                               outarg.child, &name);
1523        up_read(&fc->killsb);
1524        kfree(buf);
1525        return err;
1526
1527err:
1528        kfree(buf);
1529        fuse_copy_finish(cs);
1530        return err;
1531}
1532
1533static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1534                             struct fuse_copy_state *cs)
1535{
1536        struct fuse_notify_store_out outarg;
1537        struct inode *inode;
1538        struct address_space *mapping;
1539        u64 nodeid;
1540        int err;
1541        pgoff_t index;
1542        unsigned int offset;
1543        unsigned int num;
1544        loff_t file_size;
1545        loff_t end;
1546
1547        err = -EINVAL;
1548        if (size < sizeof(outarg))
1549                goto out_finish;
1550
1551        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1552        if (err)
1553                goto out_finish;
1554
1555        err = -EINVAL;
1556        if (size - sizeof(outarg) != outarg.size)
1557                goto out_finish;
1558
1559        nodeid = outarg.nodeid;
1560
1561        down_read(&fc->killsb);
1562
1563        err = -ENOENT;
1564        if (!fc->sb)
1565                goto out_up_killsb;
1566
1567        inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1568        if (!inode)
1569                goto out_up_killsb;
1570
1571        mapping = inode->i_mapping;
1572        index = outarg.offset >> PAGE_SHIFT;
1573        offset = outarg.offset & ~PAGE_MASK;
1574        file_size = i_size_read(inode);
1575        end = outarg.offset + outarg.size;
1576        if (end > file_size) {
1577                file_size = end;
1578                fuse_write_update_size(inode, file_size);
1579        }
1580
1581        num = outarg.size;
1582        while (num) {
1583                struct page *page;
1584                unsigned int this_num;
1585
1586                err = -ENOMEM;
1587                page = find_or_create_page(mapping, index,
1588                                           mapping_gfp_mask(mapping));
1589                if (!page)
1590                        goto out_iput;
1591
1592                this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1593                err = fuse_copy_page(cs, &page, offset, this_num, 0);
1594                if (!err && offset == 0 &&
1595                    (this_num == PAGE_SIZE || file_size == end))
1596                        SetPageUptodate(page);
1597                unlock_page(page);
1598                put_page(page);
1599
1600                if (err)
1601                        goto out_iput;
1602
1603                num -= this_num;
1604                offset = 0;
1605                index++;
1606        }
1607
1608        err = 0;
1609
1610out_iput:
1611        iput(inode);
1612out_up_killsb:
1613        up_read(&fc->killsb);
1614out_finish:
1615        fuse_copy_finish(cs);
1616        return err;
1617}
1618
1619struct fuse_retrieve_args {
1620        struct fuse_args_pages ap;
1621        struct fuse_notify_retrieve_in inarg;
1622};
1623
1624static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_args *args,
1625                              int error)
1626{
1627        struct fuse_retrieve_args *ra =
1628                container_of(args, typeof(*ra), ap.args);
1629
1630        release_pages(ra->ap.pages, ra->ap.num_pages);
1631        kfree(ra);
1632}
1633
1634static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1635                         struct fuse_notify_retrieve_out *outarg)
1636{
1637        int err;
1638        struct address_space *mapping = inode->i_mapping;
1639        pgoff_t index;
1640        loff_t file_size;
1641        unsigned int num;
1642        unsigned int offset;
1643        size_t total_len = 0;
1644        unsigned int num_pages;
1645        struct fuse_retrieve_args *ra;
1646        size_t args_size = sizeof(*ra);
1647        struct fuse_args_pages *ap;
1648        struct fuse_args *args;
1649
1650        offset = outarg->offset & ~PAGE_MASK;
1651        file_size = i_size_read(inode);
1652
1653        num = min(outarg->size, fc->max_write);
1654        if (outarg->offset > file_size)
1655                num = 0;
1656        else if (outarg->offset + num > file_size)
1657                num = file_size - outarg->offset;
1658
1659        num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1660        num_pages = min(num_pages, fc->max_pages);
1661
1662        args_size += num_pages * (sizeof(ap->pages[0]) + sizeof(ap->descs[0]));
1663
1664        ra = kzalloc(args_size, GFP_KERNEL);
1665        if (!ra)
1666                return -ENOMEM;
1667
1668        ap = &ra->ap;
1669        ap->pages = (void *) (ra + 1);
1670        ap->descs = (void *) (ap->pages + num_pages);
1671
1672        args = &ap->args;
1673        args->nodeid = outarg->nodeid;
1674        args->opcode = FUSE_NOTIFY_REPLY;
1675        args->in_numargs = 2;
1676        args->in_pages = true;
1677        args->end = fuse_retrieve_end;
1678
1679        index = outarg->offset >> PAGE_SHIFT;
1680
1681        while (num && ap->num_pages < num_pages) {
1682                struct page *page;
1683                unsigned int this_num;
1684
1685                page = find_get_page(mapping, index);
1686                if (!page)
1687                        break;
1688
1689                this_num = min_t(unsigned, num, PAGE_SIZE - offset);
1690                ap->pages[ap->num_pages] = page;
1691                ap->descs[ap->num_pages].offset = offset;
1692                ap->descs[ap->num_pages].length = this_num;
1693                ap->num_pages++;
1694
1695                offset = 0;
1696                num -= this_num;
1697                total_len += this_num;
1698                index++;
1699        }
1700        ra->inarg.offset = outarg->offset;
1701        ra->inarg.size = total_len;
1702        args->in_args[0].size = sizeof(ra->inarg);
1703        args->in_args[0].value = &ra->inarg;
1704        args->in_args[1].size = total_len;
1705
1706        err = fuse_simple_notify_reply(fc, args, outarg->notify_unique);
1707        if (err)
1708                fuse_retrieve_end(fc, args, err);
1709
1710        return err;
1711}
1712
1713static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1714                                struct fuse_copy_state *cs)
1715{
1716        struct fuse_notify_retrieve_out outarg;
1717        struct inode *inode;
1718        int err;
1719
1720        err = -EINVAL;
1721        if (size != sizeof(outarg))
1722                goto copy_finish;
1723
1724        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1725        if (err)
1726                goto copy_finish;
1727
1728        fuse_copy_finish(cs);
1729
1730        down_read(&fc->killsb);
1731        err = -ENOENT;
1732        if (fc->sb) {
1733                u64 nodeid = outarg.nodeid;
1734
1735                inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1736                if (inode) {
1737                        err = fuse_retrieve(fc, inode, &outarg);
1738                        iput(inode);
1739                }
1740        }
1741        up_read(&fc->killsb);
1742
1743        return err;
1744
1745copy_finish:
1746        fuse_copy_finish(cs);
1747        return err;
1748}
1749
1750static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1751                       unsigned int size, struct fuse_copy_state *cs)
1752{
1753        /* Don't try to move pages (yet) */
1754        cs->move_pages = 0;
1755
1756        switch (code) {
1757        case FUSE_NOTIFY_POLL:
1758                return fuse_notify_poll(fc, size, cs);
1759
1760        case FUSE_NOTIFY_INVAL_INODE:
1761                return fuse_notify_inval_inode(fc, size, cs);
1762
1763        case FUSE_NOTIFY_INVAL_ENTRY:
1764                return fuse_notify_inval_entry(fc, size, cs);
1765
1766        case FUSE_NOTIFY_STORE:
1767                return fuse_notify_store(fc, size, cs);
1768
1769        case FUSE_NOTIFY_RETRIEVE:
1770                return fuse_notify_retrieve(fc, size, cs);
1771
1772        case FUSE_NOTIFY_DELETE:
1773                return fuse_notify_delete(fc, size, cs);
1774
1775        default:
1776                fuse_copy_finish(cs);
1777                return -EINVAL;
1778        }
1779}
1780
1781/* Look up request on processing list by unique ID */
1782static struct fuse_req *request_find(struct fuse_pqueue *fpq, u64 unique)
1783{
1784        unsigned int hash = fuse_req_hash(unique);
1785        struct fuse_req *req;
1786
1787        list_for_each_entry(req, &fpq->processing[hash], list) {
1788                if (req->in.h.unique == unique)
1789                        return req;
1790        }
1791        return NULL;
1792}
1793
1794static int copy_out_args(struct fuse_copy_state *cs, struct fuse_args *args,
1795                         unsigned nbytes)
1796{
1797        unsigned reqsize = sizeof(struct fuse_out_header);
1798
1799        reqsize += fuse_len_args(args->out_numargs, args->out_args);
1800
1801        if (reqsize < nbytes || (reqsize > nbytes && !args->out_argvar))
1802                return -EINVAL;
1803        else if (reqsize > nbytes) {
1804                struct fuse_arg *lastarg = &args->out_args[args->out_numargs-1];
1805                unsigned diffsize = reqsize - nbytes;
1806
1807                if (diffsize > lastarg->size)
1808                        return -EINVAL;
1809                lastarg->size -= diffsize;
1810        }
1811        return fuse_copy_args(cs, args->out_numargs, args->out_pages,
1812                              args->out_args, args->page_zeroing);
1813}
1814
1815/*
1816 * Write a single reply to a request.  First the header is copied from
1817 * the write buffer.  The request is then searched on the processing
1818 * list by the unique ID found in the header.  If found, then remove
1819 * it from the list and copy the rest of the buffer to the request.
1820 * The request is finished by calling fuse_request_end().
1821 */
1822static ssize_t fuse_dev_do_write(struct fuse_dev *fud,
1823                                 struct fuse_copy_state *cs, size_t nbytes)
1824{
1825        int err;
1826        struct fuse_conn *fc = fud->fc;
1827        struct fuse_pqueue *fpq = &fud->pq;
1828        struct fuse_req *req;
1829        struct fuse_out_header oh;
1830
1831        err = -EINVAL;
1832        if (nbytes < sizeof(struct fuse_out_header))
1833                goto out;
1834
1835        err = fuse_copy_one(cs, &oh, sizeof(oh));
1836        if (err)
1837                goto copy_finish;
1838
1839        err = -EINVAL;
1840        if (oh.len != nbytes)
1841                goto copy_finish;
1842
1843        /*
1844         * Zero oh.unique indicates unsolicited notification message
1845         * and error contains notification code.
1846         */
1847        if (!oh.unique) {
1848                err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1849                goto out;
1850        }
1851
1852        err = -EINVAL;
1853        if (oh.error <= -1000 || oh.error > 0)
1854                goto copy_finish;
1855
1856        spin_lock(&fpq->lock);
1857        req = NULL;
1858        if (fpq->connected)
1859                req = request_find(fpq, oh.unique & ~FUSE_INT_REQ_BIT);
1860
1861        err = -ENOENT;
1862        if (!req) {
1863                spin_unlock(&fpq->lock);
1864                goto copy_finish;
1865        }
1866
1867        /* Is it an interrupt reply ID? */
1868        if (oh.unique & FUSE_INT_REQ_BIT) {
1869                __fuse_get_request(req);
1870                spin_unlock(&fpq->lock);
1871
1872                err = 0;
1873                if (nbytes != sizeof(struct fuse_out_header))
1874                        err = -EINVAL;
1875                else if (oh.error == -ENOSYS)
1876                        fc->no_interrupt = 1;
1877                else if (oh.error == -EAGAIN)
1878                        err = queue_interrupt(&fc->iq, req);
1879
1880                fuse_put_request(fc, req);
1881
1882                goto copy_finish;
1883        }
1884
1885        clear_bit(FR_SENT, &req->flags);
1886        list_move(&req->list, &fpq->io);
1887        req->out.h = oh;
1888        set_bit(FR_LOCKED, &req->flags);
1889        spin_unlock(&fpq->lock);
1890        cs->req = req;
1891        if (!req->args->page_replace)
1892                cs->move_pages = 0;
1893
1894        if (oh.error)
1895                err = nbytes != sizeof(oh) ? -EINVAL : 0;
1896        else
1897                err = copy_out_args(cs, req->args, nbytes);
1898        fuse_copy_finish(cs);
1899
1900        spin_lock(&fpq->lock);
1901        clear_bit(FR_LOCKED, &req->flags);
1902        if (!fpq->connected)
1903                err = -ENOENT;
1904        else if (err)
1905                req->out.h.error = -EIO;
1906        if (!test_bit(FR_PRIVATE, &req->flags))
1907                list_del_init(&req->list);
1908        spin_unlock(&fpq->lock);
1909
1910        fuse_request_end(fc, req);
1911out:
1912        return err ? err : nbytes;
1913
1914copy_finish:
1915        fuse_copy_finish(cs);
1916        goto out;
1917}
1918
1919static ssize_t fuse_dev_write(struct kiocb *iocb, struct iov_iter *from)
1920{
1921        struct fuse_copy_state cs;
1922        struct fuse_dev *fud = fuse_get_dev(iocb->ki_filp);
1923
1924        if (!fud)
1925                return -EPERM;
1926
1927        if (!iter_is_iovec(from))
1928                return -EINVAL;
1929
1930        fuse_copy_init(&cs, 0, from);
1931
1932        return fuse_dev_do_write(fud, &cs, iov_iter_count(from));
1933}
1934
1935static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1936                                     struct file *out, loff_t *ppos,
1937                                     size_t len, unsigned int flags)
1938{
1939        unsigned nbuf;
1940        unsigned idx;
1941        struct pipe_buffer *bufs;
1942        struct fuse_copy_state cs;
1943        struct fuse_dev *fud;
1944        size_t rem;
1945        ssize_t ret;
1946
1947        fud = fuse_get_dev(out);
1948        if (!fud)
1949                return -EPERM;
1950
1951        pipe_lock(pipe);
1952
1953        bufs = kvmalloc_array(pipe->nrbufs, sizeof(struct pipe_buffer),
1954                              GFP_KERNEL);
1955        if (!bufs) {
1956                pipe_unlock(pipe);
1957                return -ENOMEM;
1958        }
1959
1960        nbuf = 0;
1961        rem = 0;
1962        for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1963                rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1964
1965        ret = -EINVAL;
1966        if (rem < len)
1967                goto out_free;
1968
1969        rem = len;
1970        while (rem) {
1971                struct pipe_buffer *ibuf;
1972                struct pipe_buffer *obuf;
1973
1974                BUG_ON(nbuf >= pipe->buffers);
1975                BUG_ON(!pipe->nrbufs);
1976                ibuf = &pipe->bufs[pipe->curbuf];
1977                obuf = &bufs[nbuf];
1978
1979                if (rem >= ibuf->len) {
1980                        *obuf = *ibuf;
1981                        ibuf->ops = NULL;
1982                        pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1983                        pipe->nrbufs--;
1984                } else {
1985                        if (!pipe_buf_get(pipe, ibuf))
1986                                goto out_free;
1987
1988                        *obuf = *ibuf;
1989                        obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1990                        obuf->len = rem;
1991                        ibuf->offset += obuf->len;
1992                        ibuf->len -= obuf->len;
1993                }
1994                nbuf++;
1995                rem -= obuf->len;
1996        }
1997        pipe_unlock(pipe);
1998
1999        fuse_copy_init(&cs, 0, NULL);
2000        cs.pipebufs = bufs;
2001        cs.nr_segs = nbuf;
2002        cs.pipe = pipe;
2003
2004        if (flags & SPLICE_F_MOVE)
2005                cs.move_pages = 1;
2006
2007        ret = fuse_dev_do_write(fud, &cs, len);
2008
2009        pipe_lock(pipe);
2010out_free:
2011        for (idx = 0; idx < nbuf; idx++)
2012                pipe_buf_release(pipe, &bufs[idx]);
2013        pipe_unlock(pipe);
2014
2015        kvfree(bufs);
2016        return ret;
2017}
2018
2019static __poll_t fuse_dev_poll(struct file *file, poll_table *wait)
2020{
2021        __poll_t mask = EPOLLOUT | EPOLLWRNORM;
2022        struct fuse_iqueue *fiq;
2023        struct fuse_dev *fud = fuse_get_dev(file);
2024
2025        if (!fud)
2026                return EPOLLERR;
2027
2028        fiq = &fud->fc->iq;
2029        poll_wait(file, &fiq->waitq, wait);
2030
2031        spin_lock(&fiq->lock);
2032        if (!fiq->connected)
2033                mask = EPOLLERR;
2034        else if (request_pending(fiq))
2035                mask |= EPOLLIN | EPOLLRDNORM;
2036        spin_unlock(&fiq->lock);
2037
2038        return mask;
2039}
2040
2041/* Abort all requests on the given list (pending or processing) */
2042static void end_requests(struct fuse_conn *fc, struct list_head *head)
2043{
2044        while (!list_empty(head)) {
2045                struct fuse_req *req;
2046                req = list_entry(head->next, struct fuse_req, list);
2047                req->out.h.error = -ECONNABORTED;
2048                clear_bit(FR_SENT, &req->flags);
2049                list_del_init(&req->list);
2050                fuse_request_end(fc, req);
2051        }
2052}
2053
2054static void end_polls(struct fuse_conn *fc)
2055{
2056        struct rb_node *p;
2057
2058        p = rb_first(&fc->polled_files);
2059
2060        while (p) {
2061                struct fuse_file *ff;
2062                ff = rb_entry(p, struct fuse_file, polled_node);
2063                wake_up_interruptible_all(&ff->poll_wait);
2064
2065                p = rb_next(p);
2066        }
2067}
2068
2069/*
2070 * Abort all requests.
2071 *
2072 * Emergency exit in case of a malicious or accidental deadlock, or just a hung
2073 * filesystem.
2074 *
2075 * The same effect is usually achievable through killing the filesystem daemon
2076 * and all users of the filesystem.  The exception is the combination of an
2077 * asynchronous request and the tricky deadlock (see
2078 * Documentation/filesystems/fuse.txt).
2079 *
2080 * Aborting requests under I/O goes as follows: 1: Separate out unlocked
2081 * requests, they should be finished off immediately.  Locked requests will be
2082 * finished after unlock; see unlock_request(). 2: Finish off the unlocked
2083 * requests.  It is possible that some request will finish before we can.  This
2084 * is OK, the request will in that case be removed from the list before we touch
2085 * it.
2086 */
2087void fuse_abort_conn(struct fuse_conn *fc)
2088{
2089        struct fuse_iqueue *fiq = &fc->iq;
2090
2091        spin_lock(&fc->lock);
2092        if (fc->connected) {
2093                struct fuse_dev *fud;
2094                struct fuse_req *req, *next;
2095                LIST_HEAD(to_end);
2096                unsigned int i;
2097
2098                /* Background queuing checks fc->connected under bg_lock */
2099                spin_lock(&fc->bg_lock);
2100                fc->connected = 0;
2101                spin_unlock(&fc->bg_lock);
2102
2103                fuse_set_initialized(fc);
2104                list_for_each_entry(fud, &fc->devices, entry) {
2105                        struct fuse_pqueue *fpq = &fud->pq;
2106
2107                        spin_lock(&fpq->lock);
2108                        fpq->connected = 0;
2109                        list_for_each_entry_safe(req, next, &fpq->io, list) {
2110                                req->out.h.error = -ECONNABORTED;
2111                                spin_lock(&req->waitq.lock);
2112                                set_bit(FR_ABORTED, &req->flags);
2113                                if (!test_bit(FR_LOCKED, &req->flags)) {
2114                                        set_bit(FR_PRIVATE, &req->flags);
2115                                        __fuse_get_request(req);
2116                                        list_move(&req->list, &to_end);
2117                                }
2118                                spin_unlock(&req->waitq.lock);
2119                        }
2120                        for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2121                                list_splice_tail_init(&fpq->processing[i],
2122                                                      &to_end);
2123                        spin_unlock(&fpq->lock);
2124                }
2125                spin_lock(&fc->bg_lock);
2126                fc->blocked = 0;
2127                fc->max_background = UINT_MAX;
2128                flush_bg_queue(fc);
2129                spin_unlock(&fc->bg_lock);
2130
2131                spin_lock(&fiq->lock);
2132                fiq->connected = 0;
2133                list_for_each_entry(req, &fiq->pending, list)
2134                        clear_bit(FR_PENDING, &req->flags);
2135                list_splice_tail_init(&fiq->pending, &to_end);
2136                while (forget_pending(fiq))
2137                        kfree(fuse_dequeue_forget(fiq, 1, NULL));
2138                wake_up_all(&fiq->waitq);
2139                spin_unlock(&fiq->lock);
2140                kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
2141                end_polls(fc);
2142                wake_up_all(&fc->blocked_waitq);
2143                spin_unlock(&fc->lock);
2144
2145                end_requests(fc, &to_end);
2146        } else {
2147                spin_unlock(&fc->lock);
2148        }
2149}
2150EXPORT_SYMBOL_GPL(fuse_abort_conn);
2151
2152void fuse_wait_aborted(struct fuse_conn *fc)
2153{
2154        /* matches implicit memory barrier in fuse_drop_waiting() */
2155        smp_mb();
2156        wait_event(fc->blocked_waitq, atomic_read(&fc->num_waiting) == 0);
2157}
2158
2159int fuse_dev_release(struct inode *inode, struct file *file)
2160{
2161        struct fuse_dev *fud = fuse_get_dev(file);
2162
2163        if (fud) {
2164                struct fuse_conn *fc = fud->fc;
2165                struct fuse_pqueue *fpq = &fud->pq;
2166                LIST_HEAD(to_end);
2167                unsigned int i;
2168
2169                spin_lock(&fpq->lock);
2170                WARN_ON(!list_empty(&fpq->io));
2171                for (i = 0; i < FUSE_PQ_HASH_SIZE; i++)
2172                        list_splice_init(&fpq->processing[i], &to_end);
2173                spin_unlock(&fpq->lock);
2174
2175                end_requests(fc, &to_end);
2176
2177                /* Are we the last open device? */
2178                if (atomic_dec_and_test(&fc->dev_count)) {
2179                        WARN_ON(fc->iq.fasync != NULL);
2180                        fuse_abort_conn(fc);
2181                }
2182                fuse_dev_free(fud);
2183        }
2184        return 0;
2185}
2186EXPORT_SYMBOL_GPL(fuse_dev_release);
2187
2188static int fuse_dev_fasync(int fd, struct file *file, int on)
2189{
2190        struct fuse_dev *fud = fuse_get_dev(file);
2191
2192        if (!fud)
2193                return -EPERM;
2194
2195        /* No locking - fasync_helper does its own locking */
2196        return fasync_helper(fd, file, on, &fud->fc->iq.fasync);
2197}
2198
2199static int fuse_device_clone(struct fuse_conn *fc, struct file *new)
2200{
2201        struct fuse_dev *fud;
2202
2203        if (new->private_data)
2204                return -EINVAL;
2205
2206        fud = fuse_dev_alloc_install(fc);
2207        if (!fud)
2208                return -ENOMEM;
2209
2210        new->private_data = fud;
2211        atomic_inc(&fc->dev_count);
2212
2213        return 0;
2214}
2215
2216static long fuse_dev_ioctl(struct file *file, unsigned int cmd,
2217                           unsigned long arg)
2218{
2219        int err = -ENOTTY;
2220
2221        if (cmd == FUSE_DEV_IOC_CLONE) {
2222                int oldfd;
2223
2224                err = -EFAULT;
2225                if (!get_user(oldfd, (__u32 __user *) arg)) {
2226                        struct file *old = fget(oldfd);
2227
2228                        err = -EINVAL;
2229                        if (old) {
2230                                struct fuse_dev *fud = NULL;
2231
2232                                /*
2233                                 * Check against file->f_op because CUSE
2234                                 * uses the same ioctl handler.
2235                                 */
2236                                if (old->f_op == file->f_op &&
2237                                    old->f_cred->user_ns == file->f_cred->user_ns)
2238                                        fud = fuse_get_dev(old);
2239
2240                                if (fud) {
2241                                        mutex_lock(&fuse_mutex);
2242                                        err = fuse_device_clone(fud->fc, file);
2243                                        mutex_unlock(&fuse_mutex);
2244                                }
2245                                fput(old);
2246                        }
2247                }
2248        }
2249        return err;
2250}
2251
2252const struct file_operations fuse_dev_operations = {
2253        .owner          = THIS_MODULE,
2254        .open           = fuse_dev_open,
2255        .llseek         = no_llseek,
2256        .read_iter      = fuse_dev_read,
2257        .splice_read    = fuse_dev_splice_read,
2258        .write_iter     = fuse_dev_write,
2259        .splice_write   = fuse_dev_splice_write,
2260        .poll           = fuse_dev_poll,
2261        .release        = fuse_dev_release,
2262        .fasync         = fuse_dev_fasync,
2263        .unlocked_ioctl = fuse_dev_ioctl,
2264        .compat_ioctl   = compat_ptr_ioctl,
2265};
2266EXPORT_SYMBOL_GPL(fuse_dev_operations);
2267
2268static struct miscdevice fuse_miscdevice = {
2269        .minor = FUSE_MINOR,
2270        .name  = "fuse",
2271        .fops = &fuse_dev_operations,
2272};
2273
2274int __init fuse_dev_init(void)
2275{
2276        int err = -ENOMEM;
2277        fuse_req_cachep = kmem_cache_create("fuse_request",
2278                                            sizeof(struct fuse_req),
2279                                            0, 0, NULL);
2280        if (!fuse_req_cachep)
2281                goto out;
2282
2283        err = misc_register(&fuse_miscdevice);
2284        if (err)
2285                goto out_cache_clean;
2286
2287        return 0;
2288
2289 out_cache_clean:
2290        kmem_cache_destroy(fuse_req_cachep);
2291 out:
2292        return err;
2293}
2294
2295void fuse_dev_cleanup(void)
2296{
2297        misc_deregister(&fuse_miscdevice);
2298        kmem_cache_destroy(fuse_req_cachep);
2299}
2300