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/uio.h>
  15#include <linux/miscdevice.h>
  16#include <linux/pagemap.h>
  17#include <linux/file.h>
  18#include <linux/slab.h>
  19#include <linux/pipe_fs_i.h>
  20#include <linux/swap.h>
  21#include <linux/splice.h>
  22#include <linux/aio.h>
  23
  24MODULE_ALIAS_MISCDEV(FUSE_MINOR);
  25MODULE_ALIAS("devname:fuse");
  26
  27static struct kmem_cache *fuse_req_cachep;
  28
  29static struct fuse_conn *fuse_get_conn(struct file *file)
  30{
  31        /*
  32         * Lockless access is OK, because file->private data is set
  33         * once during mount and is valid until the file is released.
  34         */
  35        return file->private_data;
  36}
  37
  38static void fuse_request_init(struct fuse_req *req, struct page **pages,
  39                              struct fuse_page_desc *page_descs,
  40                              unsigned npages)
  41{
  42        memset(req, 0, sizeof(*req));
  43        memset(pages, 0, sizeof(*pages) * npages);
  44        memset(page_descs, 0, sizeof(*page_descs) * npages);
  45        INIT_LIST_HEAD(&req->list);
  46        INIT_LIST_HEAD(&req->intr_entry);
  47        init_waitqueue_head(&req->waitq);
  48        atomic_set(&req->count, 1);
  49        req->pages = pages;
  50        req->page_descs = page_descs;
  51        req->max_pages = npages;
  52}
  53
  54static struct fuse_req *__fuse_request_alloc(unsigned npages, gfp_t flags)
  55{
  56        struct fuse_req *req = kmem_cache_alloc(fuse_req_cachep, flags);
  57        if (req) {
  58                struct page **pages;
  59                struct fuse_page_desc *page_descs;
  60
  61                if (npages <= FUSE_REQ_INLINE_PAGES) {
  62                        pages = req->inline_pages;
  63                        page_descs = req->inline_page_descs;
  64                } else {
  65                        pages = kmalloc(sizeof(struct page *) * npages, flags);
  66                        page_descs = kmalloc(sizeof(struct fuse_page_desc) *
  67                                             npages, flags);
  68                }
  69
  70                if (!pages || !page_descs) {
  71                        kfree(pages);
  72                        kfree(page_descs);
  73                        kmem_cache_free(fuse_req_cachep, req);
  74                        return NULL;
  75                }
  76
  77                fuse_request_init(req, pages, page_descs, npages);
  78        }
  79        return req;
  80}
  81
  82struct fuse_req *fuse_request_alloc(unsigned npages)
  83{
  84        return __fuse_request_alloc(npages, GFP_KERNEL);
  85}
  86EXPORT_SYMBOL_GPL(fuse_request_alloc);
  87
  88struct fuse_req *fuse_request_alloc_nofs(unsigned npages)
  89{
  90        return __fuse_request_alloc(npages, GFP_NOFS);
  91}
  92
  93void fuse_request_free(struct fuse_req *req)
  94{
  95        if (req->pages != req->inline_pages) {
  96                kfree(req->pages);
  97                kfree(req->page_descs);
  98        }
  99        kmem_cache_free(fuse_req_cachep, req);
 100}
 101
 102static void block_sigs(sigset_t *oldset)
 103{
 104        sigset_t mask;
 105
 106        siginitsetinv(&mask, sigmask(SIGKILL));
 107        sigprocmask(SIG_BLOCK, &mask, oldset);
 108}
 109
 110static void restore_sigs(sigset_t *oldset)
 111{
 112        sigprocmask(SIG_SETMASK, oldset, NULL);
 113}
 114
 115void __fuse_get_request(struct fuse_req *req)
 116{
 117        atomic_inc(&req->count);
 118}
 119
 120/* Must be called with > 1 refcount */
 121static void __fuse_put_request(struct fuse_req *req)
 122{
 123        BUG_ON(atomic_read(&req->count) < 2);
 124        atomic_dec(&req->count);
 125}
 126
 127static void fuse_req_init_context(struct fuse_req *req)
 128{
 129        req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid());
 130        req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid());
 131        req->in.h.pid = current->pid;
 132}
 133
 134static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
 135{
 136        return !fc->initialized || (for_background && fc->blocked);
 137}
 138
 139static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
 140                                       bool for_background)
 141{
 142        struct fuse_req *req;
 143        int err;
 144        atomic_inc(&fc->num_waiting);
 145
 146        if (fuse_block_alloc(fc, for_background)) {
 147                sigset_t oldset;
 148                int intr;
 149
 150                block_sigs(&oldset);
 151                intr = wait_event_interruptible_exclusive(fc->blocked_waitq,
 152                                !fuse_block_alloc(fc, for_background));
 153                restore_sigs(&oldset);
 154                err = -EINTR;
 155                if (intr)
 156                        goto out;
 157        }
 158
 159        err = -ENOTCONN;
 160        if (!fc->connected)
 161                goto out;
 162
 163        req = fuse_request_alloc(npages);
 164        err = -ENOMEM;
 165        if (!req) {
 166                if (for_background)
 167                        wake_up(&fc->blocked_waitq);
 168                goto out;
 169        }
 170
 171        fuse_req_init_context(req);
 172        req->waiting = 1;
 173        req->background = for_background;
 174        return req;
 175
 176 out:
 177        atomic_dec(&fc->num_waiting);
 178        return ERR_PTR(err);
 179}
 180
 181struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages)
 182{
 183        return __fuse_get_req(fc, npages, false);
 184}
 185EXPORT_SYMBOL_GPL(fuse_get_req);
 186
 187struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
 188                                             unsigned npages)
 189{
 190        return __fuse_get_req(fc, npages, true);
 191}
 192EXPORT_SYMBOL_GPL(fuse_get_req_for_background);
 193
 194/*
 195 * Return request in fuse_file->reserved_req.  However that may
 196 * currently be in use.  If that is the case, wait for it to become
 197 * available.
 198 */
 199static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
 200                                         struct file *file)
 201{
 202        struct fuse_req *req = NULL;
 203        struct fuse_file *ff = file->private_data;
 204
 205        do {
 206                wait_event(fc->reserved_req_waitq, ff->reserved_req);
 207                spin_lock(&fc->lock);
 208                if (ff->reserved_req) {
 209                        req = ff->reserved_req;
 210                        ff->reserved_req = NULL;
 211                        req->stolen_file = get_file(file);
 212                }
 213                spin_unlock(&fc->lock);
 214        } while (!req);
 215
 216        return req;
 217}
 218
 219/*
 220 * Put stolen request back into fuse_file->reserved_req
 221 */
 222static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
 223{
 224        struct file *file = req->stolen_file;
 225        struct fuse_file *ff = file->private_data;
 226
 227        spin_lock(&fc->lock);
 228        fuse_request_init(req, req->pages, req->page_descs, req->max_pages);
 229        BUG_ON(ff->reserved_req);
 230        ff->reserved_req = req;
 231        wake_up_all(&fc->reserved_req_waitq);
 232        spin_unlock(&fc->lock);
 233        fput(file);
 234}
 235
 236/*
 237 * Gets a requests for a file operation, always succeeds
 238 *
 239 * This is used for sending the FLUSH request, which must get to
 240 * userspace, due to POSIX locks which may need to be unlocked.
 241 *
 242 * If allocation fails due to OOM, use the reserved request in
 243 * fuse_file.
 244 *
 245 * This is very unlikely to deadlock accidentally, since the
 246 * filesystem should not have it's own file open.  If deadlock is
 247 * intentional, it can still be broken by "aborting" the filesystem.
 248 */
 249struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
 250                                             struct file *file)
 251{
 252        struct fuse_req *req;
 253
 254        atomic_inc(&fc->num_waiting);
 255        wait_event(fc->blocked_waitq, fc->initialized);
 256        req = fuse_request_alloc(0);
 257        if (!req)
 258                req = get_reserved_req(fc, file);
 259
 260        fuse_req_init_context(req);
 261        req->waiting = 1;
 262        req->background = 0;
 263        return req;
 264}
 265
 266void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 267{
 268        if (atomic_dec_and_test(&req->count)) {
 269                if (unlikely(req->background)) {
 270                        /*
 271                         * We get here in the unlikely case that a background
 272                         * request was allocated but not sent
 273                         */
 274                        spin_lock(&fc->lock);
 275                        if (!fc->blocked)
 276                                wake_up(&fc->blocked_waitq);
 277                        spin_unlock(&fc->lock);
 278                }
 279
 280                if (req->waiting)
 281                        atomic_dec(&fc->num_waiting);
 282
 283                if (req->stolen_file)
 284                        put_reserved_req(fc, req);
 285                else
 286                        fuse_request_free(req);
 287        }
 288}
 289EXPORT_SYMBOL_GPL(fuse_put_request);
 290
 291static unsigned len_args(unsigned numargs, struct fuse_arg *args)
 292{
 293        unsigned nbytes = 0;
 294        unsigned i;
 295
 296        for (i = 0; i < numargs; i++)
 297                nbytes += args[i].size;
 298
 299        return nbytes;
 300}
 301
 302static u64 fuse_get_unique(struct fuse_conn *fc)
 303{
 304        fc->reqctr++;
 305        /* zero is special */
 306        if (fc->reqctr == 0)
 307                fc->reqctr = 1;
 308
 309        return fc->reqctr;
 310}
 311
 312static void queue_request(struct fuse_conn *fc, struct fuse_req *req)
 313{
 314        req->in.h.len = sizeof(struct fuse_in_header) +
 315                len_args(req->in.numargs, (struct fuse_arg *) req->in.args);
 316        list_add_tail(&req->list, &fc->pending);
 317        req->state = FUSE_REQ_PENDING;
 318        if (!req->waiting) {
 319                req->waiting = 1;
 320                atomic_inc(&fc->num_waiting);
 321        }
 322        wake_up(&fc->waitq);
 323        kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 324}
 325
 326void fuse_queue_forget(struct fuse_conn *fc, struct fuse_forget_link *forget,
 327                       u64 nodeid, u64 nlookup)
 328{
 329        forget->forget_one.nodeid = nodeid;
 330        forget->forget_one.nlookup = nlookup;
 331
 332        spin_lock(&fc->lock);
 333        if (fc->connected) {
 334                fc->forget_list_tail->next = forget;
 335                fc->forget_list_tail = forget;
 336                wake_up(&fc->waitq);
 337                kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 338        } else {
 339                kfree(forget);
 340        }
 341        spin_unlock(&fc->lock);
 342}
 343
 344static void flush_bg_queue(struct fuse_conn *fc)
 345{
 346        while (fc->active_background < fc->max_background &&
 347               !list_empty(&fc->bg_queue)) {
 348                struct fuse_req *req;
 349
 350                req = list_entry(fc->bg_queue.next, struct fuse_req, list);
 351                list_del(&req->list);
 352                fc->active_background++;
 353                req->in.h.unique = fuse_get_unique(fc);
 354                queue_request(fc, req);
 355        }
 356}
 357
 358/*
 359 * This function is called when a request is finished.  Either a reply
 360 * has arrived or it was aborted (and not yet sent) or some error
 361 * occurred during communication with userspace, or the device file
 362 * was closed.  The requester thread is woken up (if still waiting),
 363 * the 'end' callback is called if given, else the reference to the
 364 * request is released
 365 *
 366 * Called with fc->lock, unlocks it
 367 */
 368static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 369__releases(fc->lock)
 370{
 371        void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
 372        req->end = NULL;
 373        list_del(&req->list);
 374        list_del(&req->intr_entry);
 375        req->state = FUSE_REQ_FINISHED;
 376        if (req->background) {
 377                req->background = 0;
 378
 379                if (fc->num_background == fc->max_background)
 380                        fc->blocked = 0;
 381
 382                /* Wake up next waiter, if any */
 383                if (!fc->blocked && waitqueue_active(&fc->blocked_waitq))
 384                        wake_up(&fc->blocked_waitq);
 385
 386                if (fc->num_background == fc->congestion_threshold &&
 387                    fc->connected && fc->bdi_initialized) {
 388                        clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
 389                        clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
 390                }
 391                fc->num_background--;
 392                fc->active_background--;
 393                flush_bg_queue(fc);
 394        }
 395        spin_unlock(&fc->lock);
 396        wake_up(&req->waitq);
 397        if (end)
 398                end(fc, req);
 399        fuse_put_request(fc, req);
 400}
 401
 402static void wait_answer_interruptible(struct fuse_conn *fc,
 403                                      struct fuse_req *req)
 404__releases(fc->lock)
 405__acquires(fc->lock)
 406{
 407        if (signal_pending(current))
 408                return;
 409
 410        spin_unlock(&fc->lock);
 411        wait_event_interruptible(req->waitq, req->state == FUSE_REQ_FINISHED);
 412        spin_lock(&fc->lock);
 413}
 414
 415static void queue_interrupt(struct fuse_conn *fc, struct fuse_req *req)
 416{
 417        list_add_tail(&req->intr_entry, &fc->interrupts);
 418        wake_up(&fc->waitq);
 419        kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 420}
 421
 422static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req)
 423__releases(fc->lock)
 424__acquires(fc->lock)
 425{
 426        if (!fc->no_interrupt) {
 427                /* Any signal may interrupt this */
 428                wait_answer_interruptible(fc, req);
 429
 430                if (req->aborted)
 431                        goto aborted;
 432                if (req->state == FUSE_REQ_FINISHED)
 433                        return;
 434
 435                req->interrupted = 1;
 436                if (req->state == FUSE_REQ_SENT)
 437                        queue_interrupt(fc, req);
 438        }
 439
 440        if (!req->force) {
 441                sigset_t oldset;
 442
 443                /* Only fatal signals may interrupt this */
 444                block_sigs(&oldset);
 445                wait_answer_interruptible(fc, req);
 446                restore_sigs(&oldset);
 447
 448                if (req->aborted)
 449                        goto aborted;
 450                if (req->state == FUSE_REQ_FINISHED)
 451                        return;
 452
 453                /* Request is not yet in userspace, bail out */
 454                if (req->state == FUSE_REQ_PENDING) {
 455                        list_del(&req->list);
 456                        __fuse_put_request(req);
 457                        req->out.h.error = -EINTR;
 458                        return;
 459                }
 460        }
 461
 462        /*
 463         * Either request is already in userspace, or it was forced.
 464         * Wait it out.
 465         */
 466        spin_unlock(&fc->lock);
 467        wait_event(req->waitq, req->state == FUSE_REQ_FINISHED);
 468        spin_lock(&fc->lock);
 469
 470        if (!req->aborted)
 471                return;
 472
 473 aborted:
 474        BUG_ON(req->state != FUSE_REQ_FINISHED);
 475        if (req->locked) {
 476                /* This is uninterruptible sleep, because data is
 477                   being copied to/from the buffers of req.  During
 478                   locked state, there mustn't be any filesystem
 479                   operation (e.g. page fault), since that could lead
 480                   to deadlock */
 481                spin_unlock(&fc->lock);
 482                wait_event(req->waitq, !req->locked);
 483                spin_lock(&fc->lock);
 484        }
 485}
 486
 487static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 488{
 489        BUG_ON(req->background);
 490        spin_lock(&fc->lock);
 491        if (!fc->connected)
 492                req->out.h.error = -ENOTCONN;
 493        else if (fc->conn_error)
 494                req->out.h.error = -ECONNREFUSED;
 495        else {
 496                req->in.h.unique = fuse_get_unique(fc);
 497                queue_request(fc, req);
 498                /* acquire extra reference, since request is still needed
 499                   after request_end() */
 500                __fuse_get_request(req);
 501
 502                request_wait_answer(fc, req);
 503        }
 504        spin_unlock(&fc->lock);
 505}
 506
 507void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
 508{
 509        req->isreply = 1;
 510        __fuse_request_send(fc, req);
 511}
 512EXPORT_SYMBOL_GPL(fuse_request_send);
 513
 514static void fuse_request_send_nowait_locked(struct fuse_conn *fc,
 515                                            struct fuse_req *req)
 516{
 517        BUG_ON(!req->background);
 518        fc->num_background++;
 519        if (fc->num_background == fc->max_background)
 520                fc->blocked = 1;
 521        if (fc->num_background == fc->congestion_threshold &&
 522            fc->bdi_initialized) {
 523                set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
 524                set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
 525        }
 526        list_add_tail(&req->list, &fc->bg_queue);
 527        flush_bg_queue(fc);
 528}
 529
 530static void fuse_request_send_nowait(struct fuse_conn *fc, struct fuse_req *req)
 531{
 532        spin_lock(&fc->lock);
 533        if (fc->connected) {
 534                fuse_request_send_nowait_locked(fc, req);
 535                spin_unlock(&fc->lock);
 536        } else {
 537                req->out.h.error = -ENOTCONN;
 538                request_end(fc, req);
 539        }
 540}
 541
 542void fuse_request_send_background(struct fuse_conn *fc, struct fuse_req *req)
 543{
 544        req->isreply = 1;
 545        fuse_request_send_nowait(fc, req);
 546}
 547EXPORT_SYMBOL_GPL(fuse_request_send_background);
 548
 549static int fuse_request_send_notify_reply(struct fuse_conn *fc,
 550                                          struct fuse_req *req, u64 unique)
 551{
 552        int err = -ENODEV;
 553
 554        req->isreply = 0;
 555        req->in.h.unique = unique;
 556        spin_lock(&fc->lock);
 557        if (fc->connected) {
 558                queue_request(fc, req);
 559                err = 0;
 560        }
 561        spin_unlock(&fc->lock);
 562
 563        return err;
 564}
 565
 566/*
 567 * Called under fc->lock
 568 *
 569 * fc->connected must have been checked previously
 570 */
 571void fuse_request_send_background_locked(struct fuse_conn *fc,
 572                                         struct fuse_req *req)
 573{
 574        req->isreply = 1;
 575        fuse_request_send_nowait_locked(fc, req);
 576}
 577
 578void fuse_force_forget(struct file *file, u64 nodeid)
 579{
 580        struct inode *inode = file_inode(file);
 581        struct fuse_conn *fc = get_fuse_conn(inode);
 582        struct fuse_req *req;
 583        struct fuse_forget_in inarg;
 584
 585        memset(&inarg, 0, sizeof(inarg));
 586        inarg.nlookup = 1;
 587        req = fuse_get_req_nofail_nopages(fc, file);
 588        req->in.h.opcode = FUSE_FORGET;
 589        req->in.h.nodeid = nodeid;
 590        req->in.numargs = 1;
 591        req->in.args[0].size = sizeof(inarg);
 592        req->in.args[0].value = &inarg;
 593        req->isreply = 0;
 594        __fuse_request_send(fc, req);
 595        /* ignore errors */
 596        fuse_put_request(fc, req);
 597}
 598
 599/*
 600 * Lock the request.  Up to the next unlock_request() there mustn't be
 601 * anything that could cause a page-fault.  If the request was already
 602 * aborted bail out.
 603 */
 604static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
 605{
 606        int err = 0;
 607        if (req) {
 608                spin_lock(&fc->lock);
 609                if (req->aborted)
 610                        err = -ENOENT;
 611                else
 612                        req->locked = 1;
 613                spin_unlock(&fc->lock);
 614        }
 615        return err;
 616}
 617
 618/*
 619 * Unlock request.  If it was aborted during being locked, the
 620 * requester thread is currently waiting for it to be unlocked, so
 621 * wake it up.
 622 */
 623static void unlock_request(struct fuse_conn *fc, struct fuse_req *req)
 624{
 625        if (req) {
 626                spin_lock(&fc->lock);
 627                req->locked = 0;
 628                if (req->aborted)
 629                        wake_up(&req->waitq);
 630                spin_unlock(&fc->lock);
 631        }
 632}
 633
 634struct fuse_copy_state {
 635        struct fuse_conn *fc;
 636        int write;
 637        struct fuse_req *req;
 638        const struct iovec *iov;
 639        struct pipe_buffer *pipebufs;
 640        struct pipe_buffer *currbuf;
 641        struct pipe_inode_info *pipe;
 642        unsigned long nr_segs;
 643        unsigned long seglen;
 644        unsigned long addr;
 645        struct page *pg;
 646        void *mapaddr;
 647        void *buf;
 648        unsigned len;
 649        unsigned move_pages:1;
 650};
 651
 652static void fuse_copy_init(struct fuse_copy_state *cs, struct fuse_conn *fc,
 653                           int write,
 654                           const struct iovec *iov, unsigned long nr_segs)
 655{
 656        memset(cs, 0, sizeof(*cs));
 657        cs->fc = fc;
 658        cs->write = write;
 659        cs->iov = iov;
 660        cs->nr_segs = nr_segs;
 661}
 662
 663/* Unmap and put previous page of userspace buffer */
 664static void fuse_copy_finish(struct fuse_copy_state *cs)
 665{
 666        if (cs->currbuf) {
 667                struct pipe_buffer *buf = cs->currbuf;
 668
 669                if (!cs->write) {
 670                        buf->ops->unmap(cs->pipe, buf, cs->mapaddr);
 671                } else {
 672                        kunmap(buf->page);
 673                        buf->len = PAGE_SIZE - cs->len;
 674                }
 675                cs->currbuf = NULL;
 676                cs->mapaddr = NULL;
 677        } else if (cs->mapaddr) {
 678                kunmap(cs->pg);
 679                if (cs->write) {
 680                        flush_dcache_page(cs->pg);
 681                        set_page_dirty_lock(cs->pg);
 682                }
 683                put_page(cs->pg);
 684                cs->mapaddr = NULL;
 685        }
 686}
 687
 688/*
 689 * Get another pagefull of userspace buffer, and map it to kernel
 690 * address space, and lock request
 691 */
 692static int fuse_copy_fill(struct fuse_copy_state *cs)
 693{
 694        unsigned long offset;
 695        int err;
 696
 697        unlock_request(cs->fc, cs->req);
 698        fuse_copy_finish(cs);
 699        if (cs->pipebufs) {
 700                struct pipe_buffer *buf = cs->pipebufs;
 701
 702                if (!cs->write) {
 703                        err = buf->ops->confirm(cs->pipe, buf);
 704                        if (err)
 705                                return err;
 706
 707                        BUG_ON(!cs->nr_segs);
 708                        cs->currbuf = buf;
 709                        cs->mapaddr = buf->ops->map(cs->pipe, buf, 0);
 710                        cs->len = buf->len;
 711                        cs->buf = cs->mapaddr + buf->offset;
 712                        cs->pipebufs++;
 713                        cs->nr_segs--;
 714                } else {
 715                        struct page *page;
 716
 717                        if (cs->nr_segs == cs->pipe->buffers)
 718                                return -EIO;
 719
 720                        page = alloc_page(GFP_HIGHUSER);
 721                        if (!page)
 722                                return -ENOMEM;
 723
 724                        buf->page = page;
 725                        buf->offset = 0;
 726                        buf->len = 0;
 727
 728                        cs->currbuf = buf;
 729                        cs->mapaddr = kmap(page);
 730                        cs->buf = cs->mapaddr;
 731                        cs->len = PAGE_SIZE;
 732                        cs->pipebufs++;
 733                        cs->nr_segs++;
 734                }
 735        } else {
 736                if (!cs->seglen) {
 737                        BUG_ON(!cs->nr_segs);
 738                        cs->seglen = cs->iov[0].iov_len;
 739                        cs->addr = (unsigned long) cs->iov[0].iov_base;
 740                        cs->iov++;
 741                        cs->nr_segs--;
 742                }
 743                err = get_user_pages_fast(cs->addr, 1, cs->write, &cs->pg);
 744                if (err < 0)
 745                        return err;
 746                BUG_ON(err != 1);
 747                offset = cs->addr % PAGE_SIZE;
 748                cs->mapaddr = kmap(cs->pg);
 749                cs->buf = cs->mapaddr + offset;
 750                cs->len = min(PAGE_SIZE - offset, cs->seglen);
 751                cs->seglen -= cs->len;
 752                cs->addr += cs->len;
 753        }
 754
 755        return lock_request(cs->fc, cs->req);
 756}
 757
 758/* Do as much copy to/from userspace buffer as we can */
 759static int fuse_copy_do(struct fuse_copy_state *cs, void **val, unsigned *size)
 760{
 761        unsigned ncpy = min(*size, cs->len);
 762        if (val) {
 763                if (cs->write)
 764                        memcpy(cs->buf, *val, ncpy);
 765                else
 766                        memcpy(*val, cs->buf, ncpy);
 767                *val += ncpy;
 768        }
 769        *size -= ncpy;
 770        cs->len -= ncpy;
 771        cs->buf += ncpy;
 772        return ncpy;
 773}
 774
 775static int fuse_check_page(struct page *page)
 776{
 777        if (page_mapcount(page) ||
 778            page->mapping != NULL ||
 779            page_count(page) != 1 ||
 780            (page->flags & PAGE_FLAGS_CHECK_AT_PREP &
 781             ~(1 << PG_locked |
 782               1 << PG_referenced |
 783               1 << PG_uptodate |
 784               1 << PG_lru |
 785               1 << PG_active |
 786               1 << PG_reclaim))) {
 787                printk(KERN_WARNING "fuse: trying to steal weird page\n");
 788                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);
 789                return 1;
 790        }
 791        return 0;
 792}
 793
 794static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 795{
 796        int err;
 797        struct page *oldpage = *pagep;
 798        struct page *newpage;
 799        struct pipe_buffer *buf = cs->pipebufs;
 800
 801        unlock_request(cs->fc, cs->req);
 802        fuse_copy_finish(cs);
 803
 804        err = buf->ops->confirm(cs->pipe, buf);
 805        if (err)
 806                return err;
 807
 808        BUG_ON(!cs->nr_segs);
 809        cs->currbuf = buf;
 810        cs->len = buf->len;
 811        cs->pipebufs++;
 812        cs->nr_segs--;
 813
 814        if (cs->len != PAGE_SIZE)
 815                goto out_fallback;
 816
 817        if (buf->ops->steal(cs->pipe, buf) != 0)
 818                goto out_fallback;
 819
 820        newpage = buf->page;
 821
 822        if (WARN_ON(!PageUptodate(newpage)))
 823                return -EIO;
 824
 825        ClearPageMappedToDisk(newpage);
 826
 827        if (fuse_check_page(newpage) != 0)
 828                goto out_fallback_unlock;
 829
 830        /*
 831         * This is a new and locked page, it shouldn't be mapped or
 832         * have any special flags on it
 833         */
 834        if (WARN_ON(page_mapped(oldpage)))
 835                goto out_fallback_unlock;
 836        if (WARN_ON(page_has_private(oldpage)))
 837                goto out_fallback_unlock;
 838        if (WARN_ON(PageDirty(oldpage) || PageWriteback(oldpage)))
 839                goto out_fallback_unlock;
 840        if (WARN_ON(PageMlocked(oldpage)))
 841                goto out_fallback_unlock;
 842
 843        err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
 844        if (err) {
 845                unlock_page(newpage);
 846                return err;
 847        }
 848
 849        page_cache_get(newpage);
 850
 851        if (!(buf->flags & PIPE_BUF_FLAG_LRU))
 852                lru_cache_add_file(newpage);
 853
 854        err = 0;
 855        spin_lock(&cs->fc->lock);
 856        if (cs->req->aborted)
 857                err = -ENOENT;
 858        else
 859                *pagep = newpage;
 860        spin_unlock(&cs->fc->lock);
 861
 862        if (err) {
 863                unlock_page(newpage);
 864                page_cache_release(newpage);
 865                return err;
 866        }
 867
 868        unlock_page(oldpage);
 869        page_cache_release(oldpage);
 870        cs->len = 0;
 871
 872        return 0;
 873
 874out_fallback_unlock:
 875        unlock_page(newpage);
 876out_fallback:
 877        cs->mapaddr = buf->ops->map(cs->pipe, buf, 1);
 878        cs->buf = cs->mapaddr + buf->offset;
 879
 880        err = lock_request(cs->fc, cs->req);
 881        if (err)
 882                return err;
 883
 884        return 1;
 885}
 886
 887static int fuse_ref_page(struct fuse_copy_state *cs, struct page *page,
 888                         unsigned offset, unsigned count)
 889{
 890        struct pipe_buffer *buf;
 891
 892        if (cs->nr_segs == cs->pipe->buffers)
 893                return -EIO;
 894
 895        unlock_request(cs->fc, cs->req);
 896        fuse_copy_finish(cs);
 897
 898        buf = cs->pipebufs;
 899        page_cache_get(page);
 900        buf->page = page;
 901        buf->offset = offset;
 902        buf->len = count;
 903
 904        cs->pipebufs++;
 905        cs->nr_segs++;
 906        cs->len = 0;
 907
 908        return 0;
 909}
 910
 911/*
 912 * Copy a page in the request to/from the userspace buffer.  Must be
 913 * done atomically
 914 */
 915static int fuse_copy_page(struct fuse_copy_state *cs, struct page **pagep,
 916                          unsigned offset, unsigned count, int zeroing)
 917{
 918        int err;
 919        struct page *page = *pagep;
 920
 921        if (page && zeroing && count < PAGE_SIZE)
 922                clear_highpage(page);
 923
 924        while (count) {
 925                if (cs->write && cs->pipebufs && page) {
 926                        return fuse_ref_page(cs, page, offset, count);
 927                } else if (!cs->len) {
 928                        if (cs->move_pages && page &&
 929                            offset == 0 && count == PAGE_SIZE) {
 930                                err = fuse_try_move_page(cs, pagep);
 931                                if (err <= 0)
 932                                        return err;
 933                        } else {
 934                                err = fuse_copy_fill(cs);
 935                                if (err)
 936                                        return err;
 937                        }
 938                }
 939                if (page) {
 940                        void *mapaddr = kmap_atomic(page);
 941                        void *buf = mapaddr + offset;
 942                        offset += fuse_copy_do(cs, &buf, &count);
 943                        kunmap_atomic(mapaddr);
 944                } else
 945                        offset += fuse_copy_do(cs, NULL, &count);
 946        }
 947        if (page && !cs->write)
 948                flush_dcache_page(page);
 949        return 0;
 950}
 951
 952/* Copy pages in the request to/from userspace buffer */
 953static int fuse_copy_pages(struct fuse_copy_state *cs, unsigned nbytes,
 954                           int zeroing)
 955{
 956        unsigned i;
 957        struct fuse_req *req = cs->req;
 958
 959        for (i = 0; i < req->num_pages && (nbytes || zeroing); i++) {
 960                int err;
 961                unsigned offset = req->page_descs[i].offset;
 962                unsigned count = min(nbytes, req->page_descs[i].length);
 963
 964                err = fuse_copy_page(cs, &req->pages[i], offset, count,
 965                                     zeroing);
 966                if (err)
 967                        return err;
 968
 969                nbytes -= count;
 970        }
 971        return 0;
 972}
 973
 974/* Copy a single argument in the request to/from userspace buffer */
 975static int fuse_copy_one(struct fuse_copy_state *cs, void *val, unsigned size)
 976{
 977        while (size) {
 978                if (!cs->len) {
 979                        int err = fuse_copy_fill(cs);
 980                        if (err)
 981                                return err;
 982                }
 983                fuse_copy_do(cs, &val, &size);
 984        }
 985        return 0;
 986}
 987
 988/* Copy request arguments to/from userspace buffer */
 989static int fuse_copy_args(struct fuse_copy_state *cs, unsigned numargs,
 990                          unsigned argpages, struct fuse_arg *args,
 991                          int zeroing)
 992{
 993        int err = 0;
 994        unsigned i;
 995
 996        for (i = 0; !err && i < numargs; i++)  {
 997                struct fuse_arg *arg = &args[i];
 998                if (i == numargs - 1 && argpages)
 999                        err = fuse_copy_pages(cs, arg->size, zeroing);
1000                else
1001                        err = fuse_copy_one(cs, arg->value, arg->size);
1002        }
1003        return err;
1004}
1005
1006static int forget_pending(struct fuse_conn *fc)
1007{
1008        return fc->forget_list_head.next != NULL;
1009}
1010
1011static int request_pending(struct fuse_conn *fc)
1012{
1013        return !list_empty(&fc->pending) || !list_empty(&fc->interrupts) ||
1014                forget_pending(fc);
1015}
1016
1017/* Wait until a request is available on the pending list */
1018static void request_wait(struct fuse_conn *fc)
1019__releases(fc->lock)
1020__acquires(fc->lock)
1021{
1022        DECLARE_WAITQUEUE(wait, current);
1023
1024        add_wait_queue_exclusive(&fc->waitq, &wait);
1025        while (fc->connected && !request_pending(fc)) {
1026                set_current_state(TASK_INTERRUPTIBLE);
1027                if (signal_pending(current))
1028                        break;
1029
1030                spin_unlock(&fc->lock);
1031                schedule();
1032                spin_lock(&fc->lock);
1033        }
1034        set_current_state(TASK_RUNNING);
1035        remove_wait_queue(&fc->waitq, &wait);
1036}
1037
1038/*
1039 * Transfer an interrupt request to userspace
1040 *
1041 * Unlike other requests this is assembled on demand, without a need
1042 * to allocate a separate fuse_req structure.
1043 *
1044 * Called with fc->lock held, releases it
1045 */
1046static int fuse_read_interrupt(struct fuse_conn *fc, struct fuse_copy_state *cs,
1047                               size_t nbytes, struct fuse_req *req)
1048__releases(fc->lock)
1049{
1050        struct fuse_in_header ih;
1051        struct fuse_interrupt_in arg;
1052        unsigned reqsize = sizeof(ih) + sizeof(arg);
1053        int err;
1054
1055        list_del_init(&req->intr_entry);
1056        req->intr_unique = fuse_get_unique(fc);
1057        memset(&ih, 0, sizeof(ih));
1058        memset(&arg, 0, sizeof(arg));
1059        ih.len = reqsize;
1060        ih.opcode = FUSE_INTERRUPT;
1061        ih.unique = req->intr_unique;
1062        arg.unique = req->in.h.unique;
1063
1064        spin_unlock(&fc->lock);
1065        if (nbytes < reqsize)
1066                return -EINVAL;
1067
1068        err = fuse_copy_one(cs, &ih, sizeof(ih));
1069        if (!err)
1070                err = fuse_copy_one(cs, &arg, sizeof(arg));
1071        fuse_copy_finish(cs);
1072
1073        return err ? err : reqsize;
1074}
1075
1076static struct fuse_forget_link *dequeue_forget(struct fuse_conn *fc,
1077                                               unsigned max,
1078                                               unsigned *countp)
1079{
1080        struct fuse_forget_link *head = fc->forget_list_head.next;
1081        struct fuse_forget_link **newhead = &head;
1082        unsigned count;
1083
1084        for (count = 0; *newhead != NULL && count < max; count++)
1085                newhead = &(*newhead)->next;
1086
1087        fc->forget_list_head.next = *newhead;
1088        *newhead = NULL;
1089        if (fc->forget_list_head.next == NULL)
1090                fc->forget_list_tail = &fc->forget_list_head;
1091
1092        if (countp != NULL)
1093                *countp = count;
1094
1095        return head;
1096}
1097
1098static int fuse_read_single_forget(struct fuse_conn *fc,
1099                                   struct fuse_copy_state *cs,
1100                                   size_t nbytes)
1101__releases(fc->lock)
1102{
1103        int err;
1104        struct fuse_forget_link *forget = dequeue_forget(fc, 1, NULL);
1105        struct fuse_forget_in arg = {
1106                .nlookup = forget->forget_one.nlookup,
1107        };
1108        struct fuse_in_header ih = {
1109                .opcode = FUSE_FORGET,
1110                .nodeid = forget->forget_one.nodeid,
1111                .unique = fuse_get_unique(fc),
1112                .len = sizeof(ih) + sizeof(arg),
1113        };
1114
1115        spin_unlock(&fc->lock);
1116        kfree(forget);
1117        if (nbytes < ih.len)
1118                return -EINVAL;
1119
1120        err = fuse_copy_one(cs, &ih, sizeof(ih));
1121        if (!err)
1122                err = fuse_copy_one(cs, &arg, sizeof(arg));
1123        fuse_copy_finish(cs);
1124
1125        if (err)
1126                return err;
1127
1128        return ih.len;
1129}
1130
1131static int fuse_read_batch_forget(struct fuse_conn *fc,
1132                                   struct fuse_copy_state *cs, size_t nbytes)
1133__releases(fc->lock)
1134{
1135        int err;
1136        unsigned max_forgets;
1137        unsigned count;
1138        struct fuse_forget_link *head;
1139        struct fuse_batch_forget_in arg = { .count = 0 };
1140        struct fuse_in_header ih = {
1141                .opcode = FUSE_BATCH_FORGET,
1142                .unique = fuse_get_unique(fc),
1143                .len = sizeof(ih) + sizeof(arg),
1144        };
1145
1146        if (nbytes < ih.len) {
1147                spin_unlock(&fc->lock);
1148                return -EINVAL;
1149        }
1150
1151        max_forgets = (nbytes - ih.len) / sizeof(struct fuse_forget_one);
1152        head = dequeue_forget(fc, max_forgets, &count);
1153        spin_unlock(&fc->lock);
1154
1155        arg.count = count;
1156        ih.len += count * sizeof(struct fuse_forget_one);
1157        err = fuse_copy_one(cs, &ih, sizeof(ih));
1158        if (!err)
1159                err = fuse_copy_one(cs, &arg, sizeof(arg));
1160
1161        while (head) {
1162                struct fuse_forget_link *forget = head;
1163
1164                if (!err) {
1165                        err = fuse_copy_one(cs, &forget->forget_one,
1166                                            sizeof(forget->forget_one));
1167                }
1168                head = forget->next;
1169                kfree(forget);
1170        }
1171
1172        fuse_copy_finish(cs);
1173
1174        if (err)
1175                return err;
1176
1177        return ih.len;
1178}
1179
1180static int fuse_read_forget(struct fuse_conn *fc, struct fuse_copy_state *cs,
1181                            size_t nbytes)
1182__releases(fc->lock)
1183{
1184        if (fc->minor < 16 || fc->forget_list_head.next->next == NULL)
1185                return fuse_read_single_forget(fc, cs, nbytes);
1186        else
1187                return fuse_read_batch_forget(fc, cs, nbytes);
1188}
1189
1190/*
1191 * Read a single request into the userspace filesystem's buffer.  This
1192 * function waits until a request is available, then removes it from
1193 * the pending list and copies request data to userspace buffer.  If
1194 * no reply is needed (FORGET) or request has been aborted or there
1195 * was an error during the copying then it's finished by calling
1196 * request_end().  Otherwise add it to the processing list, and set
1197 * the 'sent' flag.
1198 */
1199static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
1200                                struct fuse_copy_state *cs, size_t nbytes)
1201{
1202        int err;
1203        struct fuse_req *req;
1204        struct fuse_in *in;
1205        unsigned reqsize;
1206
1207 restart:
1208        spin_lock(&fc->lock);
1209        err = -EAGAIN;
1210        if ((file->f_flags & O_NONBLOCK) && fc->connected &&
1211            !request_pending(fc))
1212                goto err_unlock;
1213
1214        request_wait(fc);
1215        err = -ENODEV;
1216        if (!fc->connected)
1217                goto err_unlock;
1218        err = -ERESTARTSYS;
1219        if (!request_pending(fc))
1220                goto err_unlock;
1221
1222        if (!list_empty(&fc->interrupts)) {
1223                req = list_entry(fc->interrupts.next, struct fuse_req,
1224                                 intr_entry);
1225                return fuse_read_interrupt(fc, cs, nbytes, req);
1226        }
1227
1228        if (forget_pending(fc)) {
1229                if (list_empty(&fc->pending) || fc->forget_batch-- > 0)
1230                        return fuse_read_forget(fc, cs, nbytes);
1231
1232                if (fc->forget_batch <= -8)
1233                        fc->forget_batch = 16;
1234        }
1235
1236        req = list_entry(fc->pending.next, struct fuse_req, list);
1237        req->state = FUSE_REQ_READING;
1238        list_move(&req->list, &fc->io);
1239
1240        in = &req->in;
1241        reqsize = in->h.len;
1242        /* If request is too large, reply with an error and restart the read */
1243        if (nbytes < reqsize) {
1244                req->out.h.error = -EIO;
1245                /* SETXATTR is special, since it may contain too large data */
1246                if (in->h.opcode == FUSE_SETXATTR)
1247                        req->out.h.error = -E2BIG;
1248                request_end(fc, req);
1249                goto restart;
1250        }
1251        spin_unlock(&fc->lock);
1252        cs->req = req;
1253        err = fuse_copy_one(cs, &in->h, sizeof(in->h));
1254        if (!err)
1255                err = fuse_copy_args(cs, in->numargs, in->argpages,
1256                                     (struct fuse_arg *) in->args, 0);
1257        fuse_copy_finish(cs);
1258        spin_lock(&fc->lock);
1259        req->locked = 0;
1260        if (req->aborted) {
1261                request_end(fc, req);
1262                return -ENODEV;
1263        }
1264        if (err) {
1265                req->out.h.error = -EIO;
1266                request_end(fc, req);
1267                return err;
1268        }
1269        if (!req->isreply)
1270                request_end(fc, req);
1271        else {
1272                req->state = FUSE_REQ_SENT;
1273                list_move_tail(&req->list, &fc->processing);
1274                if (req->interrupted)
1275                        queue_interrupt(fc, req);
1276                spin_unlock(&fc->lock);
1277        }
1278        return reqsize;
1279
1280 err_unlock:
1281        spin_unlock(&fc->lock);
1282        return err;
1283}
1284
1285static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
1286                              unsigned long nr_segs, loff_t pos)
1287{
1288        struct fuse_copy_state cs;
1289        struct file *file = iocb->ki_filp;
1290        struct fuse_conn *fc = fuse_get_conn(file);
1291        if (!fc)
1292                return -EPERM;
1293
1294        fuse_copy_init(&cs, fc, 1, iov, nr_segs);
1295
1296        return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
1297}
1298
1299static int fuse_dev_pipe_buf_steal(struct pipe_inode_info *pipe,
1300                                   struct pipe_buffer *buf)
1301{
1302        return 1;
1303}
1304
1305static const struct pipe_buf_operations fuse_dev_pipe_buf_ops = {
1306        .can_merge = 0,
1307        .map = generic_pipe_buf_map,
1308        .unmap = generic_pipe_buf_unmap,
1309        .confirm = generic_pipe_buf_confirm,
1310        .release = generic_pipe_buf_release,
1311        .steal = fuse_dev_pipe_buf_steal,
1312        .get = generic_pipe_buf_get,
1313};
1314
1315static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
1316                                    struct pipe_inode_info *pipe,
1317                                    size_t len, unsigned int flags)
1318{
1319        int ret;
1320        int page_nr = 0;
1321        int do_wakeup = 0;
1322        struct pipe_buffer *bufs;
1323        struct fuse_copy_state cs;
1324        struct fuse_conn *fc = fuse_get_conn(in);
1325        if (!fc)
1326                return -EPERM;
1327
1328        bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1329        if (!bufs)
1330                return -ENOMEM;
1331
1332        fuse_copy_init(&cs, fc, 1, NULL, 0);
1333        cs.pipebufs = bufs;
1334        cs.pipe = pipe;
1335        ret = fuse_dev_do_read(fc, in, &cs, len);
1336        if (ret < 0)
1337                goto out;
1338
1339        ret = 0;
1340        pipe_lock(pipe);
1341
1342        if (!pipe->readers) {
1343                send_sig(SIGPIPE, current, 0);
1344                if (!ret)
1345                        ret = -EPIPE;
1346                goto out_unlock;
1347        }
1348
1349        if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
1350                ret = -EIO;
1351                goto out_unlock;
1352        }
1353
1354        while (page_nr < cs.nr_segs) {
1355                int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
1356                struct pipe_buffer *buf = pipe->bufs + newbuf;
1357
1358                buf->page = bufs[page_nr].page;
1359                buf->offset = bufs[page_nr].offset;
1360                buf->len = bufs[page_nr].len;
1361                buf->ops = &fuse_dev_pipe_buf_ops;
1362
1363                pipe->nrbufs++;
1364                page_nr++;
1365                ret += buf->len;
1366
1367                if (pipe->files)
1368                        do_wakeup = 1;
1369        }
1370
1371out_unlock:
1372        pipe_unlock(pipe);
1373
1374        if (do_wakeup) {
1375                smp_mb();
1376                if (waitqueue_active(&pipe->wait))
1377                        wake_up_interruptible(&pipe->wait);
1378                kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
1379        }
1380
1381out:
1382        for (; page_nr < cs.nr_segs; page_nr++)
1383                page_cache_release(bufs[page_nr].page);
1384
1385        kfree(bufs);
1386        return ret;
1387}
1388
1389static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
1390                            struct fuse_copy_state *cs)
1391{
1392        struct fuse_notify_poll_wakeup_out outarg;
1393        int err = -EINVAL;
1394
1395        if (size != sizeof(outarg))
1396                goto err;
1397
1398        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1399        if (err)
1400                goto err;
1401
1402        fuse_copy_finish(cs);
1403        return fuse_notify_poll_wakeup(fc, &outarg);
1404
1405err:
1406        fuse_copy_finish(cs);
1407        return err;
1408}
1409
1410static int fuse_notify_inval_inode(struct fuse_conn *fc, unsigned int size,
1411                                   struct fuse_copy_state *cs)
1412{
1413        struct fuse_notify_inval_inode_out outarg;
1414        int err = -EINVAL;
1415
1416        if (size != sizeof(outarg))
1417                goto err;
1418
1419        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1420        if (err)
1421                goto err;
1422        fuse_copy_finish(cs);
1423
1424        down_read(&fc->killsb);
1425        err = -ENOENT;
1426        if (fc->sb) {
1427                err = fuse_reverse_inval_inode(fc->sb, outarg.ino,
1428                                               outarg.off, outarg.len);
1429        }
1430        up_read(&fc->killsb);
1431        return err;
1432
1433err:
1434        fuse_copy_finish(cs);
1435        return err;
1436}
1437
1438static int fuse_notify_inval_entry(struct fuse_conn *fc, unsigned int size,
1439                                   struct fuse_copy_state *cs)
1440{
1441        struct fuse_notify_inval_entry_out outarg;
1442        int err = -ENOMEM;
1443        char *buf;
1444        struct qstr name;
1445
1446        buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1447        if (!buf)
1448                goto err;
1449
1450        err = -EINVAL;
1451        if (size < sizeof(outarg))
1452                goto err;
1453
1454        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1455        if (err)
1456                goto err;
1457
1458        err = -ENAMETOOLONG;
1459        if (outarg.namelen > FUSE_NAME_MAX)
1460                goto err;
1461
1462        err = -EINVAL;
1463        if (size != sizeof(outarg) + outarg.namelen + 1)
1464                goto err;
1465
1466        name.name = buf;
1467        name.len = outarg.namelen;
1468        err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1469        if (err)
1470                goto err;
1471        fuse_copy_finish(cs);
1472        buf[outarg.namelen] = 0;
1473        name.hash = full_name_hash(name.name, name.len);
1474
1475        down_read(&fc->killsb);
1476        err = -ENOENT;
1477        if (fc->sb)
1478                err = fuse_reverse_inval_entry(fc->sb, outarg.parent, 0, &name);
1479        up_read(&fc->killsb);
1480        kfree(buf);
1481        return err;
1482
1483err:
1484        kfree(buf);
1485        fuse_copy_finish(cs);
1486        return err;
1487}
1488
1489static int fuse_notify_delete(struct fuse_conn *fc, unsigned int size,
1490                              struct fuse_copy_state *cs)
1491{
1492        struct fuse_notify_delete_out outarg;
1493        int err = -ENOMEM;
1494        char *buf;
1495        struct qstr name;
1496
1497        buf = kzalloc(FUSE_NAME_MAX + 1, GFP_KERNEL);
1498        if (!buf)
1499                goto err;
1500
1501        err = -EINVAL;
1502        if (size < sizeof(outarg))
1503                goto err;
1504
1505        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1506        if (err)
1507                goto err;
1508
1509        err = -ENAMETOOLONG;
1510        if (outarg.namelen > FUSE_NAME_MAX)
1511                goto err;
1512
1513        err = -EINVAL;
1514        if (size != sizeof(outarg) + outarg.namelen + 1)
1515                goto err;
1516
1517        name.name = buf;
1518        name.len = outarg.namelen;
1519        err = fuse_copy_one(cs, buf, outarg.namelen + 1);
1520        if (err)
1521                goto err;
1522        fuse_copy_finish(cs);
1523        buf[outarg.namelen] = 0;
1524        name.hash = full_name_hash(name.name, name.len);
1525
1526        down_read(&fc->killsb);
1527        err = -ENOENT;
1528        if (fc->sb)
1529                err = fuse_reverse_inval_entry(fc->sb, outarg.parent,
1530                                               outarg.child, &name);
1531        up_read(&fc->killsb);
1532        kfree(buf);
1533        return err;
1534
1535err:
1536        kfree(buf);
1537        fuse_copy_finish(cs);
1538        return err;
1539}
1540
1541static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
1542                             struct fuse_copy_state *cs)
1543{
1544        struct fuse_notify_store_out outarg;
1545        struct inode *inode;
1546        struct address_space *mapping;
1547        u64 nodeid;
1548        int err;
1549        pgoff_t index;
1550        unsigned int offset;
1551        unsigned int num;
1552        loff_t file_size;
1553        loff_t end;
1554
1555        err = -EINVAL;
1556        if (size < sizeof(outarg))
1557                goto out_finish;
1558
1559        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1560        if (err)
1561                goto out_finish;
1562
1563        err = -EINVAL;
1564        if (size - sizeof(outarg) != outarg.size)
1565                goto out_finish;
1566
1567        nodeid = outarg.nodeid;
1568
1569        down_read(&fc->killsb);
1570
1571        err = -ENOENT;
1572        if (!fc->sb)
1573                goto out_up_killsb;
1574
1575        inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1576        if (!inode)
1577                goto out_up_killsb;
1578
1579        mapping = inode->i_mapping;
1580        index = outarg.offset >> PAGE_CACHE_SHIFT;
1581        offset = outarg.offset & ~PAGE_CACHE_MASK;
1582        file_size = i_size_read(inode);
1583        end = outarg.offset + outarg.size;
1584        if (end > file_size) {
1585                file_size = end;
1586                fuse_write_update_size(inode, file_size);
1587        }
1588
1589        num = outarg.size;
1590        while (num) {
1591                struct page *page;
1592                unsigned int this_num;
1593
1594                err = -ENOMEM;
1595                page = find_or_create_page(mapping, index,
1596                                           mapping_gfp_mask(mapping));
1597                if (!page)
1598                        goto out_iput;
1599
1600                this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1601                err = fuse_copy_page(cs, &page, offset, this_num, 0);
1602                if (!err && offset == 0 && (num != 0 || file_size == end))
1603                        SetPageUptodate(page);
1604                unlock_page(page);
1605                page_cache_release(page);
1606
1607                if (err)
1608                        goto out_iput;
1609
1610                num -= this_num;
1611                offset = 0;
1612                index++;
1613        }
1614
1615        err = 0;
1616
1617out_iput:
1618        iput(inode);
1619out_up_killsb:
1620        up_read(&fc->killsb);
1621out_finish:
1622        fuse_copy_finish(cs);
1623        return err;
1624}
1625
1626static void fuse_retrieve_end(struct fuse_conn *fc, struct fuse_req *req)
1627{
1628        release_pages(req->pages, req->num_pages, 0);
1629}
1630
1631static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
1632                         struct fuse_notify_retrieve_out *outarg)
1633{
1634        int err;
1635        struct address_space *mapping = inode->i_mapping;
1636        struct fuse_req *req;
1637        pgoff_t index;
1638        loff_t file_size;
1639        unsigned int num;
1640        unsigned int offset;
1641        size_t total_len = 0;
1642        int num_pages;
1643
1644        offset = outarg->offset & ~PAGE_CACHE_MASK;
1645        file_size = i_size_read(inode);
1646
1647        num = outarg->size;
1648        if (outarg->offset > file_size)
1649                num = 0;
1650        else if (outarg->offset + num > file_size)
1651                num = file_size - outarg->offset;
1652
1653        num_pages = (num + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1654        num_pages = min(num_pages, FUSE_MAX_PAGES_PER_REQ);
1655
1656        req = fuse_get_req(fc, num_pages);
1657        if (IS_ERR(req))
1658                return PTR_ERR(req);
1659
1660        req->in.h.opcode = FUSE_NOTIFY_REPLY;
1661        req->in.h.nodeid = outarg->nodeid;
1662        req->in.numargs = 2;
1663        req->in.argpages = 1;
1664        req->page_descs[0].offset = offset;
1665        req->end = fuse_retrieve_end;
1666
1667        index = outarg->offset >> PAGE_CACHE_SHIFT;
1668
1669        while (num && req->num_pages < num_pages) {
1670                struct page *page;
1671                unsigned int this_num;
1672
1673                page = find_get_page(mapping, index);
1674                if (!page)
1675                        break;
1676
1677                this_num = min_t(unsigned, num, PAGE_CACHE_SIZE - offset);
1678                req->pages[req->num_pages] = page;
1679                req->page_descs[req->num_pages].length = this_num;
1680                req->num_pages++;
1681
1682                offset = 0;
1683                num -= this_num;
1684                total_len += this_num;
1685                index++;
1686        }
1687        req->misc.retrieve_in.offset = outarg->offset;
1688        req->misc.retrieve_in.size = total_len;
1689        req->in.args[0].size = sizeof(req->misc.retrieve_in);
1690        req->in.args[0].value = &req->misc.retrieve_in;
1691        req->in.args[1].size = total_len;
1692
1693        err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
1694        if (err)
1695                fuse_retrieve_end(fc, req);
1696
1697        return err;
1698}
1699
1700static int fuse_notify_retrieve(struct fuse_conn *fc, unsigned int size,
1701                                struct fuse_copy_state *cs)
1702{
1703        struct fuse_notify_retrieve_out outarg;
1704        struct inode *inode;
1705        int err;
1706
1707        err = -EINVAL;
1708        if (size != sizeof(outarg))
1709                goto copy_finish;
1710
1711        err = fuse_copy_one(cs, &outarg, sizeof(outarg));
1712        if (err)
1713                goto copy_finish;
1714
1715        fuse_copy_finish(cs);
1716
1717        down_read(&fc->killsb);
1718        err = -ENOENT;
1719        if (fc->sb) {
1720                u64 nodeid = outarg.nodeid;
1721
1722                inode = ilookup5(fc->sb, nodeid, fuse_inode_eq, &nodeid);
1723                if (inode) {
1724                        err = fuse_retrieve(fc, inode, &outarg);
1725                        iput(inode);
1726                }
1727        }
1728        up_read(&fc->killsb);
1729
1730        return err;
1731
1732copy_finish:
1733        fuse_copy_finish(cs);
1734        return err;
1735}
1736
1737static int fuse_notify(struct fuse_conn *fc, enum fuse_notify_code code,
1738                       unsigned int size, struct fuse_copy_state *cs)
1739{
1740        switch (code) {
1741        case FUSE_NOTIFY_POLL:
1742                return fuse_notify_poll(fc, size, cs);
1743
1744        case FUSE_NOTIFY_INVAL_INODE:
1745                return fuse_notify_inval_inode(fc, size, cs);
1746
1747        case FUSE_NOTIFY_INVAL_ENTRY:
1748                return fuse_notify_inval_entry(fc, size, cs);
1749
1750        case FUSE_NOTIFY_STORE:
1751                return fuse_notify_store(fc, size, cs);
1752
1753        case FUSE_NOTIFY_RETRIEVE:
1754                return fuse_notify_retrieve(fc, size, cs);
1755
1756        case FUSE_NOTIFY_DELETE:
1757                return fuse_notify_delete(fc, size, cs);
1758
1759        default:
1760                fuse_copy_finish(cs);
1761                return -EINVAL;
1762        }
1763}
1764
1765/* Look up request on processing list by unique ID */
1766static struct fuse_req *request_find(struct fuse_conn *fc, u64 unique)
1767{
1768        struct fuse_req *req;
1769
1770        list_for_each_entry(req, &fc->processing, list) {
1771                if (req->in.h.unique == unique || req->intr_unique == unique)
1772                        return req;
1773        }
1774        return NULL;
1775}
1776
1777static int copy_out_args(struct fuse_copy_state *cs, struct fuse_out *out,
1778                         unsigned nbytes)
1779{
1780        unsigned reqsize = sizeof(struct fuse_out_header);
1781
1782        if (out->h.error)
1783                return nbytes != reqsize ? -EINVAL : 0;
1784
1785        reqsize += len_args(out->numargs, out->args);
1786
1787        if (reqsize < nbytes || (reqsize > nbytes && !out->argvar))
1788                return -EINVAL;
1789        else if (reqsize > nbytes) {
1790                struct fuse_arg *lastarg = &out->args[out->numargs-1];
1791                unsigned diffsize = reqsize - nbytes;
1792                if (diffsize > lastarg->size)
1793                        return -EINVAL;
1794                lastarg->size -= diffsize;
1795        }
1796        return fuse_copy_args(cs, out->numargs, out->argpages, out->args,
1797                              out->page_zeroing);
1798}
1799
1800/*
1801 * Write a single reply to a request.  First the header is copied from
1802 * the write buffer.  The request is then searched on the processing
1803 * list by the unique ID found in the header.  If found, then remove
1804 * it from the list and copy the rest of the buffer to the request.
1805 * The request is finished by calling request_end()
1806 */
1807static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
1808                                 struct fuse_copy_state *cs, size_t nbytes)
1809{
1810        int err;
1811        struct fuse_req *req;
1812        struct fuse_out_header oh;
1813
1814        if (nbytes < sizeof(struct fuse_out_header))
1815                return -EINVAL;
1816
1817        err = fuse_copy_one(cs, &oh, sizeof(oh));
1818        if (err)
1819                goto err_finish;
1820
1821        err = -EINVAL;
1822        if (oh.len != nbytes)
1823                goto err_finish;
1824
1825        /*
1826         * Zero oh.unique indicates unsolicited notification message
1827         * and error contains notification code.
1828         */
1829        if (!oh.unique) {
1830                err = fuse_notify(fc, oh.error, nbytes - sizeof(oh), cs);
1831                return err ? err : nbytes;
1832        }
1833
1834        err = -EINVAL;
1835        if (oh.error <= -1000 || oh.error > 0)
1836                goto err_finish;
1837
1838        spin_lock(&fc->lock);
1839        err = -ENOENT;
1840        if (!fc->connected)
1841                goto err_unlock;
1842
1843        req = request_find(fc, oh.unique);
1844        if (!req)
1845                goto err_unlock;
1846
1847        if (req->aborted) {
1848                spin_unlock(&fc->lock);
1849                fuse_copy_finish(cs);
1850                spin_lock(&fc->lock);
1851                request_end(fc, req);
1852                return -ENOENT;
1853        }
1854        /* Is it an interrupt reply? */
1855        if (req->intr_unique == oh.unique) {
1856                err = -EINVAL;
1857                if (nbytes != sizeof(struct fuse_out_header))
1858                        goto err_unlock;
1859
1860                if (oh.error == -ENOSYS)
1861                        fc->no_interrupt = 1;
1862                else if (oh.error == -EAGAIN)
1863                        queue_interrupt(fc, req);
1864
1865                spin_unlock(&fc->lock);
1866                fuse_copy_finish(cs);
1867                return nbytes;
1868        }
1869
1870        req->state = FUSE_REQ_WRITING;
1871        list_move(&req->list, &fc->io);
1872        req->out.h = oh;
1873        req->locked = 1;
1874        cs->req = req;
1875        if (!req->out.page_replace)
1876                cs->move_pages = 0;
1877        spin_unlock(&fc->lock);
1878
1879        err = copy_out_args(cs, &req->out, nbytes);
1880        fuse_copy_finish(cs);
1881
1882        spin_lock(&fc->lock);
1883        req->locked = 0;
1884        if (!err) {
1885                if (req->aborted)
1886                        err = -ENOENT;
1887        } else if (!req->aborted)
1888                req->out.h.error = -EIO;
1889        request_end(fc, req);
1890
1891        return err ? err : nbytes;
1892
1893 err_unlock:
1894        spin_unlock(&fc->lock);
1895 err_finish:
1896        fuse_copy_finish(cs);
1897        return err;
1898}
1899
1900static ssize_t fuse_dev_write(struct kiocb *iocb, const struct iovec *iov,
1901                              unsigned long nr_segs, loff_t pos)
1902{
1903        struct fuse_copy_state cs;
1904        struct fuse_conn *fc = fuse_get_conn(iocb->ki_filp);
1905        if (!fc)
1906                return -EPERM;
1907
1908        fuse_copy_init(&cs, fc, 0, iov, nr_segs);
1909
1910        return fuse_dev_do_write(fc, &cs, iov_length(iov, nr_segs));
1911}
1912
1913static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
1914                                     struct file *out, loff_t *ppos,
1915                                     size_t len, unsigned int flags)
1916{
1917        unsigned nbuf;
1918        unsigned idx;
1919        struct pipe_buffer *bufs;
1920        struct fuse_copy_state cs;
1921        struct fuse_conn *fc;
1922        size_t rem;
1923        ssize_t ret;
1924
1925        fc = fuse_get_conn(out);
1926        if (!fc)
1927                return -EPERM;
1928
1929        bufs = kmalloc(pipe->buffers * sizeof(struct pipe_buffer), GFP_KERNEL);
1930        if (!bufs)
1931                return -ENOMEM;
1932
1933        pipe_lock(pipe);
1934        nbuf = 0;
1935        rem = 0;
1936        for (idx = 0; idx < pipe->nrbufs && rem < len; idx++)
1937                rem += pipe->bufs[(pipe->curbuf + idx) & (pipe->buffers - 1)].len;
1938
1939        ret = -EINVAL;
1940        if (rem < len) {
1941                pipe_unlock(pipe);
1942                goto out;
1943        }
1944
1945        rem = len;
1946        while (rem) {
1947                struct pipe_buffer *ibuf;
1948                struct pipe_buffer *obuf;
1949
1950                BUG_ON(nbuf >= pipe->buffers);
1951                BUG_ON(!pipe->nrbufs);
1952                ibuf = &pipe->bufs[pipe->curbuf];
1953                obuf = &bufs[nbuf];
1954
1955                if (rem >= ibuf->len) {
1956                        *obuf = *ibuf;
1957                        ibuf->ops = NULL;
1958                        pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
1959                        pipe->nrbufs--;
1960                } else {
1961                        ibuf->ops->get(pipe, ibuf);
1962                        *obuf = *ibuf;
1963                        obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1964                        obuf->len = rem;
1965                        ibuf->offset += obuf->len;
1966                        ibuf->len -= obuf->len;
1967                }
1968                nbuf++;
1969                rem -= obuf->len;
1970        }
1971        pipe_unlock(pipe);
1972
1973        fuse_copy_init(&cs, fc, 0, NULL, nbuf);
1974        cs.pipebufs = bufs;
1975        cs.pipe = pipe;
1976
1977        if (flags & SPLICE_F_MOVE)
1978                cs.move_pages = 1;
1979
1980        ret = fuse_dev_do_write(fc, &cs, len);
1981
1982        for (idx = 0; idx < nbuf; idx++) {
1983                struct pipe_buffer *buf = &bufs[idx];
1984                buf->ops->release(pipe, buf);
1985        }
1986out:
1987        kfree(bufs);
1988        return ret;
1989}
1990
1991static unsigned fuse_dev_poll(struct file *file, poll_table *wait)
1992{
1993        unsigned mask = POLLOUT | POLLWRNORM;
1994        struct fuse_conn *fc = fuse_get_conn(file);
1995        if (!fc)
1996                return POLLERR;
1997
1998        poll_wait(file, &fc->waitq, wait);
1999
2000        spin_lock(&fc->lock);
2001        if (!fc->connected)
2002                mask = POLLERR;
2003        else if (request_pending(fc))
2004                mask |= POLLIN | POLLRDNORM;
2005        spin_unlock(&fc->lock);
2006
2007        return mask;
2008}
2009
2010/*
2011 * Abort all requests on the given list (pending or processing)
2012 *
2013 * This function releases and reacquires fc->lock
2014 */
2015static void end_requests(struct fuse_conn *fc, struct list_head *head)
2016__releases(fc->lock)
2017__acquires(fc->lock)
2018{
2019        while (!list_empty(head)) {
2020                struct fuse_req *req;
2021                req = list_entry(head->next, struct fuse_req, list);
2022                req->out.h.error = -ECONNABORTED;
2023                request_end(fc, req);
2024                spin_lock(&fc->lock);
2025        }
2026}
2027
2028/*
2029 * Abort requests under I/O
2030 *
2031 * The requests are set to aborted and finished, and the request
2032 * waiter is woken up.  This will make request_wait_answer() wait
2033 * until the request is unlocked and then return.
2034 *
2035 * If the request is asynchronous, then the end function needs to be
2036 * called after waiting for the request to be unlocked (if it was
2037 * locked).
2038 */
2039static void end_io_requests(struct fuse_conn *fc)
2040__releases(fc->lock)
2041__acquires(fc->lock)
2042{
2043        while (!list_empty(&fc->io)) {
2044                struct fuse_req *req =
2045                        list_entry(fc->io.next, struct fuse_req, list);
2046                void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
2047
2048                req->aborted = 1;
2049                req->out.h.error = -ECONNABORTED;
2050                req->state = FUSE_REQ_FINISHED;
2051                list_del_init(&req->list);
2052                wake_up(&req->waitq);
2053                if (end) {
2054                        req->end = NULL;
2055                        __fuse_get_request(req);
2056                        spin_unlock(&fc->lock);
2057                        wait_event(req->waitq, !req->locked);
2058                        end(fc, req);
2059                        fuse_put_request(fc, req);
2060                        spin_lock(&fc->lock);
2061                }
2062        }
2063}
2064
2065static void end_queued_requests(struct fuse_conn *fc)
2066__releases(fc->lock)
2067__acquires(fc->lock)
2068{
2069        fc->max_background = UINT_MAX;
2070        flush_bg_queue(fc);
2071        end_requests(fc, &fc->pending);
2072        end_requests(fc, &fc->processing);
2073        while (forget_pending(fc))
2074                kfree(dequeue_forget(fc, 1, NULL));
2075}
2076
2077static void end_polls(struct fuse_conn *fc)
2078{
2079        struct rb_node *p;
2080
2081        p = rb_first(&fc->polled_files);
2082
2083        while (p) {
2084                struct fuse_file *ff;
2085                ff = rb_entry(p, struct fuse_file, polled_node);
2086                wake_up_interruptible_all(&ff->poll_wait);
2087
2088                p = rb_next(p);
2089        }
2090}
2091
2092/*
2093 * Abort all requests.
2094 *
2095 * Emergency exit in case of a malicious or accidental deadlock, or
2096 * just a hung filesystem.
2097 *
2098 * The same effect is usually achievable through killing the
2099 * filesystem daemon and all users of the filesystem.  The exception
2100 * is the combination of an asynchronous request and the tricky
2101 * deadlock (see Documentation/filesystems/fuse.txt).
2102 *
2103 * During the aborting, progression of requests from the pending and
2104 * processing lists onto the io list, and progression of new requests
2105 * onto the pending list is prevented by req->connected being false.
2106 *
2107 * Progression of requests under I/O to the processing list is
2108 * prevented by the req->aborted flag being true for these requests.
2109 * For this reason requests on the io list must be aborted first.
2110 */
2111void fuse_abort_conn(struct fuse_conn *fc)
2112{
2113        spin_lock(&fc->lock);
2114        if (fc->connected) {
2115                fc->connected = 0;
2116                fc->blocked = 0;
2117                fc->initialized = 1;
2118                end_io_requests(fc);
2119                end_queued_requests(fc);
2120                end_polls(fc);
2121                wake_up_all(&fc->waitq);
2122                wake_up_all(&fc->blocked_waitq);
2123                kill_fasync(&fc->fasync, SIGIO, POLL_IN);
2124        }
2125        spin_unlock(&fc->lock);
2126}
2127EXPORT_SYMBOL_GPL(fuse_abort_conn);
2128
2129int fuse_dev_release(struct inode *inode, struct file *file)
2130{
2131        struct fuse_conn *fc = fuse_get_conn(file);
2132        if (fc) {
2133                spin_lock(&fc->lock);
2134                fc->connected = 0;
2135                fc->blocked = 0;
2136                fc->initialized = 1;
2137                end_queued_requests(fc);
2138                end_polls(fc);
2139                wake_up_all(&fc->blocked_waitq);
2140                spin_unlock(&fc->lock);
2141                fuse_conn_put(fc);
2142        }
2143
2144        return 0;
2145}
2146EXPORT_SYMBOL_GPL(fuse_dev_release);
2147
2148static int fuse_dev_fasync(int fd, struct file *file, int on)
2149{
2150        struct fuse_conn *fc = fuse_get_conn(file);
2151        if (!fc)
2152                return -EPERM;
2153
2154        /* No locking - fasync_helper does its own locking */
2155        return fasync_helper(fd, file, on, &fc->fasync);
2156}
2157
2158const struct file_operations fuse_dev_operations = {
2159        .owner          = THIS_MODULE,
2160        .llseek         = no_llseek,
2161        .read           = do_sync_read,
2162        .aio_read       = fuse_dev_read,
2163        .splice_read    = fuse_dev_splice_read,
2164        .write          = do_sync_write,
2165        .aio_write      = fuse_dev_write,
2166        .splice_write   = fuse_dev_splice_write,
2167        .poll           = fuse_dev_poll,
2168        .release        = fuse_dev_release,
2169        .fasync         = fuse_dev_fasync,
2170};
2171EXPORT_SYMBOL_GPL(fuse_dev_operations);
2172
2173static struct miscdevice fuse_miscdevice = {
2174        .minor = FUSE_MINOR,
2175        .name  = "fuse",
2176        .fops = &fuse_dev_operations,
2177};
2178
2179int __init fuse_dev_init(void)
2180{
2181        int err = -ENOMEM;
2182        fuse_req_cachep = kmem_cache_create("fuse_request",
2183                                            sizeof(struct fuse_req),
2184                                            0, 0, NULL);
2185        if (!fuse_req_cachep)
2186                goto out;
2187
2188        err = misc_register(&fuse_miscdevice);
2189        if (err)
2190                goto out_cache_clean;
2191
2192        return 0;
2193
2194 out_cache_clean:
2195        kmem_cache_destroy(fuse_req_cachep);
2196 out:
2197        return err;
2198}
2199
2200void fuse_dev_cleanup(void)
2201{
2202        misc_deregister(&fuse_miscdevice);
2203        kmem_cache_destroy(fuse_req_cachep);
2204}
2205