linux/fs/fuse/file.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/pagemap.h>
  12#include <linux/slab.h>
  13#include <linux/kernel.h>
  14#include <linux/sched.h>
  15#include <linux/module.h>
  16#include <linux/compat.h>
  17#include <linux/swap.h>
  18
  19static const struct file_operations fuse_direct_io_file_operations;
  20
  21static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
  22                          int opcode, struct fuse_open_out *outargp)
  23{
  24        struct fuse_open_in inarg;
  25        struct fuse_req *req;
  26        int err;
  27
  28        req = fuse_get_req(fc);
  29        if (IS_ERR(req))
  30                return PTR_ERR(req);
  31
  32        memset(&inarg, 0, sizeof(inarg));
  33        inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
  34        if (!fc->atomic_o_trunc)
  35                inarg.flags &= ~O_TRUNC;
  36        req->in.h.opcode = opcode;
  37        req->in.h.nodeid = nodeid;
  38        req->in.numargs = 1;
  39        req->in.args[0].size = sizeof(inarg);
  40        req->in.args[0].value = &inarg;
  41        req->out.numargs = 1;
  42        req->out.args[0].size = sizeof(*outargp);
  43        req->out.args[0].value = outargp;
  44        fuse_request_send(fc, req);
  45        err = req->out.h.error;
  46        fuse_put_request(fc, req);
  47
  48        return err;
  49}
  50
  51struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
  52{
  53        struct fuse_file *ff;
  54
  55        ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
  56        if (unlikely(!ff))
  57                return NULL;
  58
  59        ff->fc = fc;
  60        ff->reserved_req = fuse_request_alloc();
  61        if (unlikely(!ff->reserved_req)) {
  62                kfree(ff);
  63                return NULL;
  64        }
  65
  66        INIT_LIST_HEAD(&ff->write_entry);
  67        atomic_set(&ff->count, 0);
  68        RB_CLEAR_NODE(&ff->polled_node);
  69        init_waitqueue_head(&ff->poll_wait);
  70
  71        spin_lock(&fc->lock);
  72        ff->kh = ++fc->khctr;
  73        spin_unlock(&fc->lock);
  74
  75        return ff;
  76}
  77
  78void fuse_file_free(struct fuse_file *ff)
  79{
  80        fuse_request_free(ff->reserved_req);
  81        kfree(ff);
  82}
  83
  84struct fuse_file *fuse_file_get(struct fuse_file *ff)
  85{
  86        atomic_inc(&ff->count);
  87        return ff;
  88}
  89
  90static void fuse_release_async(struct work_struct *work)
  91{
  92        struct fuse_req *req;
  93        struct fuse_conn *fc;
  94        struct path path;
  95
  96        req = container_of(work, struct fuse_req, misc.release.work);
  97        path = req->misc.release.path;
  98        fc = get_fuse_conn(path.dentry->d_inode);
  99
 100        fuse_put_request(fc, req);
 101        path_put(&path);
 102}
 103
 104static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
 105{
 106        if (fc->destroy_req) {
 107                /*
 108                 * If this is a fuseblk mount, then it's possible that
 109                 * releasing the path will result in releasing the
 110                 * super block and sending the DESTROY request.  If
 111                 * the server is single threaded, this would hang.
 112                 * For this reason do the path_put() in a separate
 113                 * thread.
 114                 */
 115                atomic_inc(&req->count);
 116                INIT_WORK(&req->misc.release.work, fuse_release_async);
 117                schedule_work(&req->misc.release.work);
 118        } else {
 119                path_put(&req->misc.release.path);
 120        }
 121}
 122
 123static void fuse_file_put(struct fuse_file *ff, bool sync)
 124{
 125        if (atomic_dec_and_test(&ff->count)) {
 126                struct fuse_req *req = ff->reserved_req;
 127
 128                if (sync) {
 129                        fuse_request_send(ff->fc, req);
 130                        path_put(&req->misc.release.path);
 131                        fuse_put_request(ff->fc, req);
 132                } else {
 133                        req->end = fuse_release_end;
 134                        fuse_request_send_background(ff->fc, req);
 135                }
 136                kfree(ff);
 137        }
 138}
 139
 140int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 141                 bool isdir)
 142{
 143        struct fuse_open_out outarg;
 144        struct fuse_file *ff;
 145        int err;
 146        int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
 147
 148        ff = fuse_file_alloc(fc);
 149        if (!ff)
 150                return -ENOMEM;
 151
 152        err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
 153        if (err) {
 154                fuse_file_free(ff);
 155                return err;
 156        }
 157
 158        if (isdir)
 159                outarg.open_flags &= ~FOPEN_DIRECT_IO;
 160
 161        ff->fh = outarg.fh;
 162        ff->nodeid = nodeid;
 163        ff->open_flags = outarg.open_flags;
 164        file->private_data = fuse_file_get(ff);
 165
 166        return 0;
 167}
 168EXPORT_SYMBOL_GPL(fuse_do_open);
 169
 170void fuse_finish_open(struct inode *inode, struct file *file)
 171{
 172        struct fuse_file *ff = file->private_data;
 173        struct fuse_conn *fc = get_fuse_conn(inode);
 174
 175        if (ff->open_flags & FOPEN_DIRECT_IO)
 176                file->f_op = &fuse_direct_io_file_operations;
 177        if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 178                invalidate_inode_pages2(inode->i_mapping);
 179        if (ff->open_flags & FOPEN_NONSEEKABLE)
 180                nonseekable_open(inode, file);
 181        if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
 182                struct fuse_inode *fi = get_fuse_inode(inode);
 183
 184                spin_lock(&fc->lock);
 185                fi->attr_version = ++fc->attr_version;
 186                i_size_write(inode, 0);
 187                spin_unlock(&fc->lock);
 188                fuse_invalidate_attr(inode);
 189        }
 190}
 191
 192int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 193{
 194        struct fuse_conn *fc = get_fuse_conn(inode);
 195        int err;
 196
 197        err = generic_file_open(inode, file);
 198        if (err)
 199                return err;
 200
 201        err = fuse_do_open(fc, get_node_id(inode), file, isdir);
 202        if (err)
 203                return err;
 204
 205        fuse_finish_open(inode, file);
 206
 207        return 0;
 208}
 209
 210static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
 211{
 212        struct fuse_conn *fc = ff->fc;
 213        struct fuse_req *req = ff->reserved_req;
 214        struct fuse_release_in *inarg = &req->misc.release.in;
 215
 216        spin_lock(&fc->lock);
 217        list_del(&ff->write_entry);
 218        if (!RB_EMPTY_NODE(&ff->polled_node))
 219                rb_erase(&ff->polled_node, &fc->polled_files);
 220        spin_unlock(&fc->lock);
 221
 222        wake_up_interruptible_all(&ff->poll_wait);
 223
 224        inarg->fh = ff->fh;
 225        inarg->flags = flags;
 226        req->in.h.opcode = opcode;
 227        req->in.h.nodeid = ff->nodeid;
 228        req->in.numargs = 1;
 229        req->in.args[0].size = sizeof(struct fuse_release_in);
 230        req->in.args[0].value = inarg;
 231}
 232
 233void fuse_release_common(struct file *file, int opcode)
 234{
 235        struct fuse_file *ff;
 236        struct fuse_req *req;
 237
 238        ff = file->private_data;
 239        if (unlikely(!ff))
 240                return;
 241
 242        req = ff->reserved_req;
 243        fuse_prepare_release(ff, file->f_flags, opcode);
 244
 245        if (ff->flock) {
 246                struct fuse_release_in *inarg = &req->misc.release.in;
 247                inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
 248                inarg->lock_owner = fuse_lock_owner_id(ff->fc,
 249                                                       (fl_owner_t) file);
 250        }
 251        /* Hold vfsmount and dentry until release is finished */
 252        path_get(&file->f_path);
 253        req->misc.release.path = file->f_path;
 254
 255        /*
 256         * Normally this will send the RELEASE request, however if
 257         * some asynchronous READ or WRITE requests are outstanding,
 258         * the sending will be delayed.
 259         *
 260         * Make the release synchronous if this is a fuseblk mount,
 261         * synchronous RELEASE is allowed (and desirable) in this case
 262         * because the server can be trusted not to screw up.
 263         */
 264        fuse_file_put(ff, ff->fc->destroy_req != NULL);
 265}
 266
 267static int fuse_open(struct inode *inode, struct file *file)
 268{
 269        return fuse_open_common(inode, file, false);
 270}
 271
 272static int fuse_release(struct inode *inode, struct file *file)
 273{
 274        fuse_release_common(file, FUSE_RELEASE);
 275
 276        /* return value is ignored by VFS */
 277        return 0;
 278}
 279
 280void fuse_sync_release(struct fuse_file *ff, int flags)
 281{
 282        WARN_ON(atomic_read(&ff->count) > 1);
 283        fuse_prepare_release(ff, flags, FUSE_RELEASE);
 284        ff->reserved_req->force = 1;
 285        fuse_request_send(ff->fc, ff->reserved_req);
 286        fuse_put_request(ff->fc, ff->reserved_req);
 287        kfree(ff);
 288}
 289EXPORT_SYMBOL_GPL(fuse_sync_release);
 290
 291/*
 292 * Scramble the ID space with XTEA, so that the value of the files_struct
 293 * pointer is not exposed to userspace.
 294 */
 295u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 296{
 297        u32 *k = fc->scramble_key;
 298        u64 v = (unsigned long) id;
 299        u32 v0 = v;
 300        u32 v1 = v >> 32;
 301        u32 sum = 0;
 302        int i;
 303
 304        for (i = 0; i < 32; i++) {
 305                v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
 306                sum += 0x9E3779B9;
 307                v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
 308        }
 309
 310        return (u64) v0 + ((u64) v1 << 32);
 311}
 312
 313/*
 314 * Check if page is under writeback
 315 *
 316 * This is currently done by walking the list of writepage requests
 317 * for the inode, which can be pretty inefficient.
 318 */
 319static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
 320{
 321        struct fuse_conn *fc = get_fuse_conn(inode);
 322        struct fuse_inode *fi = get_fuse_inode(inode);
 323        struct fuse_req *req;
 324        bool found = false;
 325
 326        spin_lock(&fc->lock);
 327        list_for_each_entry(req, &fi->writepages, writepages_entry) {
 328                pgoff_t curr_index;
 329
 330                BUG_ON(req->inode != inode);
 331                curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
 332                if (curr_index == index) {
 333                        found = true;
 334                        break;
 335                }
 336        }
 337        spin_unlock(&fc->lock);
 338
 339        return found;
 340}
 341
 342/*
 343 * Wait for page writeback to be completed.
 344 *
 345 * Since fuse doesn't rely on the VM writeback tracking, this has to
 346 * use some other means.
 347 */
 348static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
 349{
 350        struct fuse_inode *fi = get_fuse_inode(inode);
 351
 352        wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
 353        return 0;
 354}
 355
 356static int fuse_flush(struct file *file, fl_owner_t id)
 357{
 358        struct inode *inode = file->f_path.dentry->d_inode;
 359        struct fuse_conn *fc = get_fuse_conn(inode);
 360        struct fuse_file *ff = file->private_data;
 361        struct fuse_req *req;
 362        struct fuse_flush_in inarg;
 363        int err;
 364
 365        if (is_bad_inode(inode))
 366                return -EIO;
 367
 368        if (fc->no_flush)
 369                return 0;
 370
 371        req = fuse_get_req_nofail(fc, file);
 372        memset(&inarg, 0, sizeof(inarg));
 373        inarg.fh = ff->fh;
 374        inarg.lock_owner = fuse_lock_owner_id(fc, id);
 375        req->in.h.opcode = FUSE_FLUSH;
 376        req->in.h.nodeid = get_node_id(inode);
 377        req->in.numargs = 1;
 378        req->in.args[0].size = sizeof(inarg);
 379        req->in.args[0].value = &inarg;
 380        req->force = 1;
 381        fuse_request_send(fc, req);
 382        err = req->out.h.error;
 383        fuse_put_request(fc, req);
 384        if (err == -ENOSYS) {
 385                fc->no_flush = 1;
 386                err = 0;
 387        }
 388        return err;
 389}
 390
 391/*
 392 * Wait for all pending writepages on the inode to finish.
 393 *
 394 * This is currently done by blocking further writes with FUSE_NOWRITE
 395 * and waiting for all sent writes to complete.
 396 *
 397 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
 398 * could conflict with truncation.
 399 */
 400static void fuse_sync_writes(struct inode *inode)
 401{
 402        fuse_set_nowrite(inode);
 403        fuse_release_nowrite(inode);
 404}
 405
 406int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 407                      int datasync, int isdir)
 408{
 409        struct inode *inode = file->f_mapping->host;
 410        struct fuse_conn *fc = get_fuse_conn(inode);
 411        struct fuse_file *ff = file->private_data;
 412        struct fuse_req *req;
 413        struct fuse_fsync_in inarg;
 414        int err;
 415
 416        if (is_bad_inode(inode))
 417                return -EIO;
 418
 419        err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 420        if (err)
 421                return err;
 422
 423        if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 424                return 0;
 425
 426        mutex_lock(&inode->i_mutex);
 427
 428        /*
 429         * Start writeback against all dirty pages of the inode, then
 430         * wait for all outstanding writes, before sending the FSYNC
 431         * request.
 432         */
 433        err = write_inode_now(inode, 0);
 434        if (err)
 435                goto out;
 436
 437        fuse_sync_writes(inode);
 438
 439        req = fuse_get_req(fc);
 440        if (IS_ERR(req)) {
 441                err = PTR_ERR(req);
 442                goto out;
 443        }
 444
 445        memset(&inarg, 0, sizeof(inarg));
 446        inarg.fh = ff->fh;
 447        inarg.fsync_flags = datasync ? 1 : 0;
 448        req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 449        req->in.h.nodeid = get_node_id(inode);
 450        req->in.numargs = 1;
 451        req->in.args[0].size = sizeof(inarg);
 452        req->in.args[0].value = &inarg;
 453        fuse_request_send(fc, req);
 454        err = req->out.h.error;
 455        fuse_put_request(fc, req);
 456        if (err == -ENOSYS) {
 457                if (isdir)
 458                        fc->no_fsyncdir = 1;
 459                else
 460                        fc->no_fsync = 1;
 461                err = 0;
 462        }
 463out:
 464        mutex_unlock(&inode->i_mutex);
 465        return err;
 466}
 467
 468static int fuse_fsync(struct file *file, loff_t start, loff_t end,
 469                      int datasync)
 470{
 471        return fuse_fsync_common(file, start, end, datasync, 0);
 472}
 473
 474void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
 475                    size_t count, int opcode)
 476{
 477        struct fuse_read_in *inarg = &req->misc.read.in;
 478        struct fuse_file *ff = file->private_data;
 479
 480        inarg->fh = ff->fh;
 481        inarg->offset = pos;
 482        inarg->size = count;
 483        inarg->flags = file->f_flags;
 484        req->in.h.opcode = opcode;
 485        req->in.h.nodeid = ff->nodeid;
 486        req->in.numargs = 1;
 487        req->in.args[0].size = sizeof(struct fuse_read_in);
 488        req->in.args[0].value = inarg;
 489        req->out.argvar = 1;
 490        req->out.numargs = 1;
 491        req->out.args[0].size = count;
 492}
 493
 494static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 495                             loff_t pos, size_t count, fl_owner_t owner)
 496{
 497        struct fuse_file *ff = file->private_data;
 498        struct fuse_conn *fc = ff->fc;
 499
 500        fuse_read_fill(req, file, pos, count, FUSE_READ);
 501        if (owner != NULL) {
 502                struct fuse_read_in *inarg = &req->misc.read.in;
 503
 504                inarg->read_flags |= FUSE_READ_LOCKOWNER;
 505                inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 506        }
 507        fuse_request_send(fc, req);
 508        return req->out.args[0].size;
 509}
 510
 511static void fuse_read_update_size(struct inode *inode, loff_t size,
 512                                  u64 attr_ver)
 513{
 514        struct fuse_conn *fc = get_fuse_conn(inode);
 515        struct fuse_inode *fi = get_fuse_inode(inode);
 516
 517        spin_lock(&fc->lock);
 518        if (attr_ver == fi->attr_version && size < inode->i_size) {
 519                fi->attr_version = ++fc->attr_version;
 520                i_size_write(inode, size);
 521        }
 522        spin_unlock(&fc->lock);
 523}
 524
 525static int fuse_readpage(struct file *file, struct page *page)
 526{
 527        struct inode *inode = page->mapping->host;
 528        struct fuse_conn *fc = get_fuse_conn(inode);
 529        struct fuse_req *req;
 530        size_t num_read;
 531        loff_t pos = page_offset(page);
 532        size_t count = PAGE_CACHE_SIZE;
 533        u64 attr_ver;
 534        int err;
 535
 536        err = -EIO;
 537        if (is_bad_inode(inode))
 538                goto out;
 539
 540        /*
 541         * Page writeback can extend beyond the lifetime of the
 542         * page-cache page, so make sure we read a properly synced
 543         * page.
 544         */
 545        fuse_wait_on_page_writeback(inode, page->index);
 546
 547        req = fuse_get_req(fc);
 548        err = PTR_ERR(req);
 549        if (IS_ERR(req))
 550                goto out;
 551
 552        attr_ver = fuse_get_attr_version(fc);
 553
 554        req->out.page_zeroing = 1;
 555        req->out.argpages = 1;
 556        req->num_pages = 1;
 557        req->pages[0] = page;
 558        num_read = fuse_send_read(req, file, pos, count, NULL);
 559        err = req->out.h.error;
 560        fuse_put_request(fc, req);
 561
 562        if (!err) {
 563                /*
 564                 * Short read means EOF.  If file size is larger, truncate it
 565                 */
 566                if (num_read < count)
 567                        fuse_read_update_size(inode, pos + num_read, attr_ver);
 568
 569                SetPageUptodate(page);
 570        }
 571
 572        fuse_invalidate_attr(inode); /* atime changed */
 573 out:
 574        unlock_page(page);
 575        return err;
 576}
 577
 578static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 579{
 580        int i;
 581        size_t count = req->misc.read.in.size;
 582        size_t num_read = req->out.args[0].size;
 583        struct address_space *mapping = NULL;
 584
 585        for (i = 0; mapping == NULL && i < req->num_pages; i++)
 586                mapping = req->pages[i]->mapping;
 587
 588        if (mapping) {
 589                struct inode *inode = mapping->host;
 590
 591                /*
 592                 * Short read means EOF. If file size is larger, truncate it
 593                 */
 594                if (!req->out.h.error && num_read < count) {
 595                        loff_t pos;
 596
 597                        pos = page_offset(req->pages[0]) + num_read;
 598                        fuse_read_update_size(inode, pos,
 599                                              req->misc.read.attr_ver);
 600                }
 601                fuse_invalidate_attr(inode); /* atime changed */
 602        }
 603
 604        for (i = 0; i < req->num_pages; i++) {
 605                struct page *page = req->pages[i];
 606                if (!req->out.h.error)
 607                        SetPageUptodate(page);
 608                else
 609                        SetPageError(page);
 610                unlock_page(page);
 611                page_cache_release(page);
 612        }
 613        if (req->ff)
 614                fuse_file_put(req->ff, false);
 615}
 616
 617static void fuse_send_readpages(struct fuse_req *req, struct file *file)
 618{
 619        struct fuse_file *ff = file->private_data;
 620        struct fuse_conn *fc = ff->fc;
 621        loff_t pos = page_offset(req->pages[0]);
 622        size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 623
 624        req->out.argpages = 1;
 625        req->out.page_zeroing = 1;
 626        req->out.page_replace = 1;
 627        fuse_read_fill(req, file, pos, count, FUSE_READ);
 628        req->misc.read.attr_ver = fuse_get_attr_version(fc);
 629        if (fc->async_read) {
 630                req->ff = fuse_file_get(ff);
 631                req->end = fuse_readpages_end;
 632                fuse_request_send_background(fc, req);
 633        } else {
 634                fuse_request_send(fc, req);
 635                fuse_readpages_end(fc, req);
 636                fuse_put_request(fc, req);
 637        }
 638}
 639
 640struct fuse_fill_data {
 641        struct fuse_req *req;
 642        struct file *file;
 643        struct inode *inode;
 644};
 645
 646static int fuse_readpages_fill(void *_data, struct page *page)
 647{
 648        struct fuse_fill_data *data = _data;
 649        struct fuse_req *req = data->req;
 650        struct inode *inode = data->inode;
 651        struct fuse_conn *fc = get_fuse_conn(inode);
 652
 653        fuse_wait_on_page_writeback(inode, page->index);
 654
 655        if (req->num_pages &&
 656            (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 657             (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 658             req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 659                fuse_send_readpages(req, data->file);
 660                data->req = req = fuse_get_req(fc);
 661                if (IS_ERR(req)) {
 662                        unlock_page(page);
 663                        return PTR_ERR(req);
 664                }
 665        }
 666        page_cache_get(page);
 667        req->pages[req->num_pages] = page;
 668        req->num_pages++;
 669        return 0;
 670}
 671
 672static int fuse_readpages(struct file *file, struct address_space *mapping,
 673                          struct list_head *pages, unsigned nr_pages)
 674{
 675        struct inode *inode = mapping->host;
 676        struct fuse_conn *fc = get_fuse_conn(inode);
 677        struct fuse_fill_data data;
 678        int err;
 679
 680        err = -EIO;
 681        if (is_bad_inode(inode))
 682                goto out;
 683
 684        data.file = file;
 685        data.inode = inode;
 686        data.req = fuse_get_req(fc);
 687        err = PTR_ERR(data.req);
 688        if (IS_ERR(data.req))
 689                goto out;
 690
 691        err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 692        if (!err) {
 693                if (data.req->num_pages)
 694                        fuse_send_readpages(data.req, file);
 695                else
 696                        fuse_put_request(fc, data.req);
 697        }
 698out:
 699        return err;
 700}
 701
 702static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 703                                  unsigned long nr_segs, loff_t pos)
 704{
 705        struct inode *inode = iocb->ki_filp->f_mapping->host;
 706        struct fuse_conn *fc = get_fuse_conn(inode);
 707
 708        /*
 709         * In auto invalidate mode, always update attributes on read.
 710         * Otherwise, only update if we attempt to read past EOF (to ensure
 711         * i_size is up to date).
 712         */
 713        if (fc->auto_inval_data ||
 714            (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
 715                int err;
 716                err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 717                if (err)
 718                        return err;
 719        }
 720
 721        return generic_file_aio_read(iocb, iov, nr_segs, pos);
 722}
 723
 724static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 725                            loff_t pos, size_t count)
 726{
 727        struct fuse_write_in *inarg = &req->misc.write.in;
 728        struct fuse_write_out *outarg = &req->misc.write.out;
 729
 730        inarg->fh = ff->fh;
 731        inarg->offset = pos;
 732        inarg->size = count;
 733        req->in.h.opcode = FUSE_WRITE;
 734        req->in.h.nodeid = ff->nodeid;
 735        req->in.numargs = 2;
 736        if (ff->fc->minor < 9)
 737                req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 738        else
 739                req->in.args[0].size = sizeof(struct fuse_write_in);
 740        req->in.args[0].value = inarg;
 741        req->in.args[1].size = count;
 742        req->out.numargs = 1;
 743        req->out.args[0].size = sizeof(struct fuse_write_out);
 744        req->out.args[0].value = outarg;
 745}
 746
 747static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 748                              loff_t pos, size_t count, fl_owner_t owner)
 749{
 750        struct fuse_file *ff = file->private_data;
 751        struct fuse_conn *fc = ff->fc;
 752        struct fuse_write_in *inarg = &req->misc.write.in;
 753
 754        fuse_write_fill(req, ff, pos, count);
 755        inarg->flags = file->f_flags;
 756        if (owner != NULL) {
 757                inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 758                inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 759        }
 760        fuse_request_send(fc, req);
 761        return req->misc.write.out.size;
 762}
 763
 764void fuse_write_update_size(struct inode *inode, loff_t pos)
 765{
 766        struct fuse_conn *fc = get_fuse_conn(inode);
 767        struct fuse_inode *fi = get_fuse_inode(inode);
 768
 769        spin_lock(&fc->lock);
 770        fi->attr_version = ++fc->attr_version;
 771        if (pos > inode->i_size)
 772                i_size_write(inode, pos);
 773        spin_unlock(&fc->lock);
 774}
 775
 776static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
 777                                    struct inode *inode, loff_t pos,
 778                                    size_t count)
 779{
 780        size_t res;
 781        unsigned offset;
 782        unsigned i;
 783
 784        for (i = 0; i < req->num_pages; i++)
 785                fuse_wait_on_page_writeback(inode, req->pages[i]->index);
 786
 787        res = fuse_send_write(req, file, pos, count, NULL);
 788
 789        offset = req->page_offset;
 790        count = res;
 791        for (i = 0; i < req->num_pages; i++) {
 792                struct page *page = req->pages[i];
 793
 794                if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
 795                        SetPageUptodate(page);
 796
 797                if (count > PAGE_CACHE_SIZE - offset)
 798                        count -= PAGE_CACHE_SIZE - offset;
 799                else
 800                        count = 0;
 801                offset = 0;
 802
 803                unlock_page(page);
 804                page_cache_release(page);
 805        }
 806
 807        return res;
 808}
 809
 810static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 811                               struct address_space *mapping,
 812                               struct iov_iter *ii, loff_t pos)
 813{
 814        struct fuse_conn *fc = get_fuse_conn(mapping->host);
 815        unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 816        size_t count = 0;
 817        int err;
 818
 819        req->in.argpages = 1;
 820        req->page_offset = offset;
 821
 822        do {
 823                size_t tmp;
 824                struct page *page;
 825                pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 826                size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
 827                                     iov_iter_count(ii));
 828
 829                bytes = min_t(size_t, bytes, fc->max_write - count);
 830
 831 again:
 832                err = -EFAULT;
 833                if (iov_iter_fault_in_readable(ii, bytes))
 834                        break;
 835
 836                err = -ENOMEM;
 837                page = grab_cache_page_write_begin(mapping, index, 0);
 838                if (!page)
 839                        break;
 840
 841                if (mapping_writably_mapped(mapping))
 842                        flush_dcache_page(page);
 843
 844                pagefault_disable();
 845                tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
 846                pagefault_enable();
 847                flush_dcache_page(page);
 848
 849                mark_page_accessed(page);
 850
 851                if (!tmp) {
 852                        unlock_page(page);
 853                        page_cache_release(page);
 854                        bytes = min(bytes, iov_iter_single_seg_count(ii));
 855                        goto again;
 856                }
 857
 858                err = 0;
 859                req->pages[req->num_pages] = page;
 860                req->num_pages++;
 861
 862                iov_iter_advance(ii, tmp);
 863                count += tmp;
 864                pos += tmp;
 865                offset += tmp;
 866                if (offset == PAGE_CACHE_SIZE)
 867                        offset = 0;
 868
 869                if (!fc->big_writes)
 870                        break;
 871        } while (iov_iter_count(ii) && count < fc->max_write &&
 872                 req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
 873
 874        return count > 0 ? count : err;
 875}
 876
 877static ssize_t fuse_perform_write(struct file *file,
 878                                  struct address_space *mapping,
 879                                  struct iov_iter *ii, loff_t pos)
 880{
 881        struct inode *inode = mapping->host;
 882        struct fuse_conn *fc = get_fuse_conn(inode);
 883        int err = 0;
 884        ssize_t res = 0;
 885
 886        if (is_bad_inode(inode))
 887                return -EIO;
 888
 889        do {
 890                struct fuse_req *req;
 891                ssize_t count;
 892
 893                req = fuse_get_req(fc);
 894                if (IS_ERR(req)) {
 895                        err = PTR_ERR(req);
 896                        break;
 897                }
 898
 899                count = fuse_fill_write_pages(req, mapping, ii, pos);
 900                if (count <= 0) {
 901                        err = count;
 902                } else {
 903                        size_t num_written;
 904
 905                        num_written = fuse_send_write_pages(req, file, inode,
 906                                                            pos, count);
 907                        err = req->out.h.error;
 908                        if (!err) {
 909                                res += num_written;
 910                                pos += num_written;
 911
 912                                /* break out of the loop on short write */
 913                                if (num_written != count)
 914                                        err = -EIO;
 915                        }
 916                }
 917                fuse_put_request(fc, req);
 918        } while (!err && iov_iter_count(ii));
 919
 920        if (res > 0)
 921                fuse_write_update_size(inode, pos);
 922
 923        fuse_invalidate_attr(inode);
 924
 925        return res > 0 ? res : err;
 926}
 927
 928static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 929                                   unsigned long nr_segs, loff_t pos)
 930{
 931        struct file *file = iocb->ki_filp;
 932        struct address_space *mapping = file->f_mapping;
 933        size_t count = 0;
 934        size_t ocount = 0;
 935        ssize_t written = 0;
 936        ssize_t written_buffered = 0;
 937        struct inode *inode = mapping->host;
 938        ssize_t err;
 939        struct iov_iter i;
 940        loff_t endbyte = 0;
 941
 942        WARN_ON(iocb->ki_pos != pos);
 943
 944        ocount = 0;
 945        err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
 946        if (err)
 947                return err;
 948
 949        count = ocount;
 950        sb_start_write(inode->i_sb);
 951        mutex_lock(&inode->i_mutex);
 952
 953        /* We can write back this queue in page reclaim */
 954        current->backing_dev_info = mapping->backing_dev_info;
 955
 956        err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 957        if (err)
 958                goto out;
 959
 960        if (count == 0)
 961                goto out;
 962
 963        err = file_remove_suid(file);
 964        if (err)
 965                goto out;
 966
 967        err = file_update_time(file);
 968        if (err)
 969                goto out;
 970
 971        if (file->f_flags & O_DIRECT) {
 972                written = generic_file_direct_write(iocb, iov, &nr_segs,
 973                                                    pos, &iocb->ki_pos,
 974                                                    count, ocount);
 975                if (written < 0 || written == count)
 976                        goto out;
 977
 978                pos += written;
 979                count -= written;
 980
 981                iov_iter_init(&i, iov, nr_segs, count, written);
 982                written_buffered = fuse_perform_write(file, mapping, &i, pos);
 983                if (written_buffered < 0) {
 984                        err = written_buffered;
 985                        goto out;
 986                }
 987                endbyte = pos + written_buffered - 1;
 988
 989                err = filemap_write_and_wait_range(file->f_mapping, pos,
 990                                                   endbyte);
 991                if (err)
 992                        goto out;
 993
 994                invalidate_mapping_pages(file->f_mapping,
 995                                         pos >> PAGE_CACHE_SHIFT,
 996                                         endbyte >> PAGE_CACHE_SHIFT);
 997
 998                written += written_buffered;
 999                iocb->ki_pos = pos + written_buffered;
1000        } else {
1001                iov_iter_init(&i, iov, nr_segs, count, 0);
1002                written = fuse_perform_write(file, mapping, &i, pos);
1003                if (written >= 0)
1004                        iocb->ki_pos = pos + written;
1005        }
1006out:
1007        current->backing_dev_info = NULL;
1008        mutex_unlock(&inode->i_mutex);
1009        sb_end_write(inode->i_sb);
1010
1011        return written ? written : err;
1012}
1013
1014static void fuse_release_user_pages(struct fuse_req *req, int write)
1015{
1016        unsigned i;
1017
1018        for (i = 0; i < req->num_pages; i++) {
1019                struct page *page = req->pages[i];
1020                if (write)
1021                        set_page_dirty_lock(page);
1022                put_page(page);
1023        }
1024}
1025
1026static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
1027                               size_t *nbytesp, int write)
1028{
1029        size_t nbytes = *nbytesp;
1030        unsigned long user_addr = (unsigned long) buf;
1031        unsigned offset = user_addr & ~PAGE_MASK;
1032        int npages;
1033
1034        /* Special case for kernel I/O: can copy directly into the buffer */
1035        if (segment_eq(get_fs(), KERNEL_DS)) {
1036                if (write)
1037                        req->in.args[1].value = (void *) user_addr;
1038                else
1039                        req->out.args[0].value = (void *) user_addr;
1040
1041                return 0;
1042        }
1043
1044        nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
1045        npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1046        npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
1047        npages = get_user_pages_fast(user_addr, npages, !write, req->pages);
1048        if (npages < 0)
1049                return npages;
1050
1051        req->num_pages = npages;
1052        req->page_offset = offset;
1053
1054        if (write)
1055                req->in.argpages = 1;
1056        else
1057                req->out.argpages = 1;
1058
1059        nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
1060        *nbytesp = min(*nbytesp, nbytes);
1061
1062        return 0;
1063}
1064
1065ssize_t fuse_direct_io(struct file *file, const char __user *buf,
1066                       size_t count, loff_t *ppos, int write)
1067{
1068        struct fuse_file *ff = file->private_data;
1069        struct fuse_conn *fc = ff->fc;
1070        size_t nmax = write ? fc->max_write : fc->max_read;
1071        loff_t pos = *ppos;
1072        ssize_t res = 0;
1073        struct fuse_req *req;
1074
1075        req = fuse_get_req(fc);
1076        if (IS_ERR(req))
1077                return PTR_ERR(req);
1078
1079        while (count) {
1080                size_t nres;
1081                fl_owner_t owner = current->files;
1082                size_t nbytes = min(count, nmax);
1083                int err = fuse_get_user_pages(req, buf, &nbytes, write);
1084                if (err) {
1085                        res = err;
1086                        break;
1087                }
1088
1089                if (write)
1090                        nres = fuse_send_write(req, file, pos, nbytes, owner);
1091                else
1092                        nres = fuse_send_read(req, file, pos, nbytes, owner);
1093
1094                fuse_release_user_pages(req, !write);
1095                if (req->out.h.error) {
1096                        if (!res)
1097                                res = req->out.h.error;
1098                        break;
1099                } else if (nres > nbytes) {
1100                        res = -EIO;
1101                        break;
1102                }
1103                count -= nres;
1104                res += nres;
1105                pos += nres;
1106                buf += nres;
1107                if (nres != nbytes)
1108                        break;
1109                if (count) {
1110                        fuse_put_request(fc, req);
1111                        req = fuse_get_req(fc);
1112                        if (IS_ERR(req))
1113                                break;
1114                }
1115        }
1116        if (!IS_ERR(req))
1117                fuse_put_request(fc, req);
1118        if (res > 0)
1119                *ppos = pos;
1120
1121        return res;
1122}
1123EXPORT_SYMBOL_GPL(fuse_direct_io);
1124
1125static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1126                                     size_t count, loff_t *ppos)
1127{
1128        ssize_t res;
1129        struct inode *inode = file->f_path.dentry->d_inode;
1130
1131        if (is_bad_inode(inode))
1132                return -EIO;
1133
1134        res = fuse_direct_io(file, buf, count, ppos, 0);
1135
1136        fuse_invalidate_attr(inode);
1137
1138        return res;
1139}
1140
1141static ssize_t __fuse_direct_write(struct file *file, const char __user *buf,
1142                                   size_t count, loff_t *ppos)
1143{
1144        struct inode *inode = file->f_path.dentry->d_inode;
1145        ssize_t res;
1146
1147        res = generic_write_checks(file, ppos, &count, 0);
1148        if (!res) {
1149                res = fuse_direct_io(file, buf, count, ppos, 1);
1150                if (res > 0)
1151                        fuse_write_update_size(inode, *ppos);
1152        }
1153
1154        fuse_invalidate_attr(inode);
1155
1156        return res;
1157}
1158
1159static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1160                                 size_t count, loff_t *ppos)
1161{
1162        struct inode *inode = file->f_path.dentry->d_inode;
1163        ssize_t res;
1164
1165        if (is_bad_inode(inode))
1166                return -EIO;
1167
1168        /* Don't allow parallel writes to the same file */
1169        mutex_lock(&inode->i_mutex);
1170        res = __fuse_direct_write(file, buf, count, ppos);
1171        mutex_unlock(&inode->i_mutex);
1172
1173        return res;
1174}
1175
1176static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1177{
1178        __free_page(req->pages[0]);
1179        fuse_file_put(req->ff, false);
1180}
1181
1182static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1183{
1184        struct inode *inode = req->inode;
1185        struct fuse_inode *fi = get_fuse_inode(inode);
1186        struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1187
1188        list_del(&req->writepages_entry);
1189        dec_bdi_stat(bdi, BDI_WRITEBACK);
1190        dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
1191        bdi_writeout_inc(bdi);
1192        wake_up(&fi->page_waitq);
1193}
1194
1195/* Called under fc->lock, may release and reacquire it */
1196static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
1197__releases(fc->lock)
1198__acquires(fc->lock)
1199{
1200        struct fuse_inode *fi = get_fuse_inode(req->inode);
1201        loff_t size = i_size_read(req->inode);
1202        struct fuse_write_in *inarg = &req->misc.write.in;
1203
1204        if (!fc->connected)
1205                goto out_free;
1206
1207        if (inarg->offset + PAGE_CACHE_SIZE <= size) {
1208                inarg->size = PAGE_CACHE_SIZE;
1209        } else if (inarg->offset < size) {
1210                inarg->size = size & (PAGE_CACHE_SIZE - 1);
1211        } else {
1212                /* Got truncated off completely */
1213                goto out_free;
1214        }
1215
1216        req->in.args[1].size = inarg->size;
1217        fi->writectr++;
1218        fuse_request_send_background_locked(fc, req);
1219        return;
1220
1221 out_free:
1222        fuse_writepage_finish(fc, req);
1223        spin_unlock(&fc->lock);
1224        fuse_writepage_free(fc, req);
1225        fuse_put_request(fc, req);
1226        spin_lock(&fc->lock);
1227}
1228
1229/*
1230 * If fi->writectr is positive (no truncate or fsync going on) send
1231 * all queued writepage requests.
1232 *
1233 * Called with fc->lock
1234 */
1235void fuse_flush_writepages(struct inode *inode)
1236__releases(fc->lock)
1237__acquires(fc->lock)
1238{
1239        struct fuse_conn *fc = get_fuse_conn(inode);
1240        struct fuse_inode *fi = get_fuse_inode(inode);
1241        struct fuse_req *req;
1242
1243        while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1244                req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1245                list_del_init(&req->list);
1246                fuse_send_writepage(fc, req);
1247        }
1248}
1249
1250static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1251{
1252        struct inode *inode = req->inode;
1253        struct fuse_inode *fi = get_fuse_inode(inode);
1254
1255        mapping_set_error(inode->i_mapping, req->out.h.error);
1256        spin_lock(&fc->lock);
1257        fi->writectr--;
1258        fuse_writepage_finish(fc, req);
1259        spin_unlock(&fc->lock);
1260        fuse_writepage_free(fc, req);
1261}
1262
1263static int fuse_writepage_locked(struct page *page)
1264{
1265        struct address_space *mapping = page->mapping;
1266        struct inode *inode = mapping->host;
1267        struct fuse_conn *fc = get_fuse_conn(inode);
1268        struct fuse_inode *fi = get_fuse_inode(inode);
1269        struct fuse_req *req;
1270        struct fuse_file *ff;
1271        struct page *tmp_page;
1272
1273        set_page_writeback(page);
1274
1275        req = fuse_request_alloc_nofs();
1276        if (!req)
1277                goto err;
1278
1279        tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1280        if (!tmp_page)
1281                goto err_free;
1282
1283        spin_lock(&fc->lock);
1284        BUG_ON(list_empty(&fi->write_files));
1285        ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
1286        req->ff = fuse_file_get(ff);
1287        spin_unlock(&fc->lock);
1288
1289        fuse_write_fill(req, ff, page_offset(page), 0);
1290
1291        copy_highpage(tmp_page, page);
1292        req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1293        req->in.argpages = 1;
1294        req->num_pages = 1;
1295        req->pages[0] = tmp_page;
1296        req->page_offset = 0;
1297        req->end = fuse_writepage_end;
1298        req->inode = inode;
1299
1300        inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1301        inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1302        end_page_writeback(page);
1303
1304        spin_lock(&fc->lock);
1305        list_add(&req->writepages_entry, &fi->writepages);
1306        list_add_tail(&req->list, &fi->queued_writes);
1307        fuse_flush_writepages(inode);
1308        spin_unlock(&fc->lock);
1309
1310        return 0;
1311
1312err_free:
1313        fuse_request_free(req);
1314err:
1315        end_page_writeback(page);
1316        return -ENOMEM;
1317}
1318
1319static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1320{
1321        int err;
1322
1323        err = fuse_writepage_locked(page);
1324        unlock_page(page);
1325
1326        return err;
1327}
1328
1329static int fuse_launder_page(struct page *page)
1330{
1331        int err = 0;
1332        if (clear_page_dirty_for_io(page)) {
1333                struct inode *inode = page->mapping->host;
1334                err = fuse_writepage_locked(page);
1335                if (!err)
1336                        fuse_wait_on_page_writeback(inode, page->index);
1337        }
1338        return err;
1339}
1340
1341/*
1342 * Write back dirty pages now, because there may not be any suitable
1343 * open files later
1344 */
1345static void fuse_vma_close(struct vm_area_struct *vma)
1346{
1347        filemap_write_and_wait(vma->vm_file->f_mapping);
1348}
1349
1350/*
1351 * Wait for writeback against this page to complete before allowing it
1352 * to be marked dirty again, and hence written back again, possibly
1353 * before the previous writepage completed.
1354 *
1355 * Block here, instead of in ->writepage(), so that the userspace fs
1356 * can only block processes actually operating on the filesystem.
1357 *
1358 * Otherwise unprivileged userspace fs would be able to block
1359 * unrelated:
1360 *
1361 * - page migration
1362 * - sync(2)
1363 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
1364 */
1365static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1366{
1367        struct page *page = vmf->page;
1368        /*
1369         * Don't use page->mapping as it may become NULL from a
1370         * concurrent truncate.
1371         */
1372        struct inode *inode = vma->vm_file->f_mapping->host;
1373
1374        fuse_wait_on_page_writeback(inode, page->index);
1375        return 0;
1376}
1377
1378static const struct vm_operations_struct fuse_file_vm_ops = {
1379        .close          = fuse_vma_close,
1380        .fault          = filemap_fault,
1381        .page_mkwrite   = fuse_page_mkwrite,
1382        .remap_pages    = generic_file_remap_pages,
1383};
1384
1385static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
1386{
1387        if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
1388                struct inode *inode = file->f_dentry->d_inode;
1389                struct fuse_conn *fc = get_fuse_conn(inode);
1390                struct fuse_inode *fi = get_fuse_inode(inode);
1391                struct fuse_file *ff = file->private_data;
1392                /*
1393                 * file may be written through mmap, so chain it onto the
1394                 * inodes's write_file list
1395                 */
1396                spin_lock(&fc->lock);
1397                if (list_empty(&ff->write_entry))
1398                        list_add(&ff->write_entry, &fi->write_files);
1399                spin_unlock(&fc->lock);
1400        }
1401        file_accessed(file);
1402        vma->vm_ops = &fuse_file_vm_ops;
1403        return 0;
1404}
1405
1406static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
1407{
1408        /* Can't provide the coherency needed for MAP_SHARED */
1409        if (vma->vm_flags & VM_MAYSHARE)
1410                return -ENODEV;
1411
1412        invalidate_inode_pages2(file->f_mapping);
1413
1414        return generic_file_mmap(file, vma);
1415}
1416
1417static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
1418                                  struct file_lock *fl)
1419{
1420        switch (ffl->type) {
1421        case F_UNLCK:
1422                break;
1423
1424        case F_RDLCK:
1425        case F_WRLCK:
1426                if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
1427                    ffl->end < ffl->start)
1428                        return -EIO;
1429
1430                fl->fl_start = ffl->start;
1431                fl->fl_end = ffl->end;
1432                fl->fl_pid = ffl->pid;
1433                break;
1434
1435        default:
1436                return -EIO;
1437        }
1438        fl->fl_type = ffl->type;
1439        return 0;
1440}
1441
1442static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1443                         const struct file_lock *fl, int opcode, pid_t pid,
1444                         int flock)
1445{
1446        struct inode *inode = file->f_path.dentry->d_inode;
1447        struct fuse_conn *fc = get_fuse_conn(inode);
1448        struct fuse_file *ff = file->private_data;
1449        struct fuse_lk_in *arg = &req->misc.lk_in;
1450
1451        arg->fh = ff->fh;
1452        arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1453        arg->lk.start = fl->fl_start;
1454        arg->lk.end = fl->fl_end;
1455        arg->lk.type = fl->fl_type;
1456        arg->lk.pid = pid;
1457        if (flock)
1458                arg->lk_flags |= FUSE_LK_FLOCK;
1459        req->in.h.opcode = opcode;
1460        req->in.h.nodeid = get_node_id(inode);
1461        req->in.numargs = 1;
1462        req->in.args[0].size = sizeof(*arg);
1463        req->in.args[0].value = arg;
1464}
1465
1466static int fuse_getlk(struct file *file, struct file_lock *fl)
1467{
1468        struct inode *inode = file->f_path.dentry->d_inode;
1469        struct fuse_conn *fc = get_fuse_conn(inode);
1470        struct fuse_req *req;
1471        struct fuse_lk_out outarg;
1472        int err;
1473
1474        req = fuse_get_req(fc);
1475        if (IS_ERR(req))
1476                return PTR_ERR(req);
1477
1478        fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1479        req->out.numargs = 1;
1480        req->out.args[0].size = sizeof(outarg);
1481        req->out.args[0].value = &outarg;
1482        fuse_request_send(fc, req);
1483        err = req->out.h.error;
1484        fuse_put_request(fc, req);
1485        if (!err)
1486                err = convert_fuse_file_lock(&outarg.lk, fl);
1487
1488        return err;
1489}
1490
1491static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1492{
1493        struct inode *inode = file->f_path.dentry->d_inode;
1494        struct fuse_conn *fc = get_fuse_conn(inode);
1495        struct fuse_req *req;
1496        int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
1497        pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
1498        int err;
1499
1500        if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
1501                /* NLM needs asynchronous locks, which we don't support yet */
1502                return -ENOLCK;
1503        }
1504
1505        /* Unlock on close is handled by the flush method */
1506        if (fl->fl_flags & FL_CLOSE)
1507                return 0;
1508
1509        req = fuse_get_req(fc);
1510        if (IS_ERR(req))
1511                return PTR_ERR(req);
1512
1513        fuse_lk_fill(req, file, fl, opcode, pid, flock);
1514        fuse_request_send(fc, req);
1515        err = req->out.h.error;
1516        /* locking is restartable */
1517        if (err == -EINTR)
1518                err = -ERESTARTSYS;
1519        fuse_put_request(fc, req);
1520        return err;
1521}
1522
1523static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
1524{
1525        struct inode *inode = file->f_path.dentry->d_inode;
1526        struct fuse_conn *fc = get_fuse_conn(inode);
1527        int err;
1528
1529        if (cmd == F_CANCELLK) {
1530                err = 0;
1531        } else if (cmd == F_GETLK) {
1532                if (fc->no_lock) {
1533                        posix_test_lock(file, fl);
1534                        err = 0;
1535                } else
1536                        err = fuse_getlk(file, fl);
1537        } else {
1538                if (fc->no_lock)
1539                        err = posix_lock_file(file, fl, NULL);
1540                else
1541                        err = fuse_setlk(file, fl, 0);
1542        }
1543        return err;
1544}
1545
1546static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
1547{
1548        struct inode *inode = file->f_path.dentry->d_inode;
1549        struct fuse_conn *fc = get_fuse_conn(inode);
1550        int err;
1551
1552        if (fc->no_flock) {
1553                err = flock_lock_file_wait(file, fl);
1554        } else {
1555                struct fuse_file *ff = file->private_data;
1556
1557                /* emulate flock with POSIX locks */
1558                fl->fl_owner = (fl_owner_t) file;
1559                ff->flock = true;
1560                err = fuse_setlk(file, fl, 1);
1561        }
1562
1563        return err;
1564}
1565
1566static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
1567{
1568        struct inode *inode = mapping->host;
1569        struct fuse_conn *fc = get_fuse_conn(inode);
1570        struct fuse_req *req;
1571        struct fuse_bmap_in inarg;
1572        struct fuse_bmap_out outarg;
1573        int err;
1574
1575        if (!inode->i_sb->s_bdev || fc->no_bmap)
1576                return 0;
1577
1578        req = fuse_get_req(fc);
1579        if (IS_ERR(req))
1580                return 0;
1581
1582        memset(&inarg, 0, sizeof(inarg));
1583        inarg.block = block;
1584        inarg.blocksize = inode->i_sb->s_blocksize;
1585        req->in.h.opcode = FUSE_BMAP;
1586        req->in.h.nodeid = get_node_id(inode);
1587        req->in.numargs = 1;
1588        req->in.args[0].size = sizeof(inarg);
1589        req->in.args[0].value = &inarg;
1590        req->out.numargs = 1;
1591        req->out.args[0].size = sizeof(outarg);
1592        req->out.args[0].value = &outarg;
1593        fuse_request_send(fc, req);
1594        err = req->out.h.error;
1595        fuse_put_request(fc, req);
1596        if (err == -ENOSYS)
1597                fc->no_bmap = 1;
1598
1599        return err ? 0 : outarg.block;
1600}
1601
1602static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
1603{
1604        loff_t retval;
1605        struct inode *inode = file->f_path.dentry->d_inode;
1606
1607        /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
1608        if (origin == SEEK_CUR || origin == SEEK_SET)
1609                return generic_file_llseek(file, offset, origin);
1610
1611        mutex_lock(&inode->i_mutex);
1612        retval = fuse_update_attributes(inode, NULL, file, NULL);
1613        if (!retval)
1614                retval = generic_file_llseek(file, offset, origin);
1615        mutex_unlock(&inode->i_mutex);
1616
1617        return retval;
1618}
1619
1620static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
1621                        unsigned int nr_segs, size_t bytes, bool to_user)
1622{
1623        struct iov_iter ii;
1624        int page_idx = 0;
1625
1626        if (!bytes)
1627                return 0;
1628
1629        iov_iter_init(&ii, iov, nr_segs, bytes, 0);
1630
1631        while (iov_iter_count(&ii)) {
1632                struct page *page = pages[page_idx++];
1633                size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
1634                void *kaddr;
1635
1636                kaddr = kmap(page);
1637
1638                while (todo) {
1639                        char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
1640                        size_t iov_len = ii.iov->iov_len - ii.iov_offset;
1641                        size_t copy = min(todo, iov_len);
1642                        size_t left;
1643
1644                        if (!to_user)
1645                                left = copy_from_user(kaddr, uaddr, copy);
1646                        else
1647                                left = copy_to_user(uaddr, kaddr, copy);
1648
1649                        if (unlikely(left))
1650                                return -EFAULT;
1651
1652                        iov_iter_advance(&ii, copy);
1653                        todo -= copy;
1654                        kaddr += copy;
1655                }
1656
1657                kunmap(page);
1658        }
1659
1660        return 0;
1661}
1662
1663/*
1664 * CUSE servers compiled on 32bit broke on 64bit kernels because the
1665 * ABI was defined to be 'struct iovec' which is different on 32bit
1666 * and 64bit.  Fortunately we can determine which structure the server
1667 * used from the size of the reply.
1668 */
1669static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
1670                                     size_t transferred, unsigned count,
1671                                     bool is_compat)
1672{
1673#ifdef CONFIG_COMPAT
1674        if (count * sizeof(struct compat_iovec) == transferred) {
1675                struct compat_iovec *ciov = src;
1676                unsigned i;
1677
1678                /*
1679                 * With this interface a 32bit server cannot support
1680                 * non-compat (i.e. ones coming from 64bit apps) ioctl
1681                 * requests
1682                 */
1683                if (!is_compat)
1684                        return -EINVAL;
1685
1686                for (i = 0; i < count; i++) {
1687                        dst[i].iov_base = compat_ptr(ciov[i].iov_base);
1688                        dst[i].iov_len = ciov[i].iov_len;
1689                }
1690                return 0;
1691        }
1692#endif
1693
1694        if (count * sizeof(struct iovec) != transferred)
1695                return -EIO;
1696
1697        memcpy(dst, src, transferred);
1698        return 0;
1699}
1700
1701/* Make sure iov_length() won't overflow */
1702static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
1703{
1704        size_t n;
1705        u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
1706
1707        for (n = 0; n < count; n++, iov++) {
1708                if (iov->iov_len > (size_t) max)
1709                        return -ENOMEM;
1710                max -= iov->iov_len;
1711        }
1712        return 0;
1713}
1714
1715static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
1716                                 void *src, size_t transferred, unsigned count,
1717                                 bool is_compat)
1718{
1719        unsigned i;
1720        struct fuse_ioctl_iovec *fiov = src;
1721
1722        if (fc->minor < 16) {
1723                return fuse_copy_ioctl_iovec_old(dst, src, transferred,
1724                                                 count, is_compat);
1725        }
1726
1727        if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
1728                return -EIO;
1729
1730        for (i = 0; i < count; i++) {
1731                /* Did the server supply an inappropriate value? */
1732                if (fiov[i].base != (unsigned long) fiov[i].base ||
1733                    fiov[i].len != (unsigned long) fiov[i].len)
1734                        return -EIO;
1735
1736                dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
1737                dst[i].iov_len = (size_t) fiov[i].len;
1738
1739#ifdef CONFIG_COMPAT
1740                if (is_compat &&
1741                    (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
1742                     (compat_size_t) dst[i].iov_len != fiov[i].len))
1743                        return -EIO;
1744#endif
1745        }
1746
1747        return 0;
1748}
1749
1750
1751/*
1752 * For ioctls, there is no generic way to determine how much memory
1753 * needs to be read and/or written.  Furthermore, ioctls are allowed
1754 * to dereference the passed pointer, so the parameter requires deep
1755 * copying but FUSE has no idea whatsoever about what to copy in or
1756 * out.
1757 *
1758 * This is solved by allowing FUSE server to retry ioctl with
1759 * necessary in/out iovecs.  Let's assume the ioctl implementation
1760 * needs to read in the following structure.
1761 *
1762 * struct a {
1763 *      char    *buf;
1764 *      size_t  buflen;
1765 * }
1766 *
1767 * On the first callout to FUSE server, inarg->in_size and
1768 * inarg->out_size will be NULL; then, the server completes the ioctl
1769 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
1770 * the actual iov array to
1771 *
1772 * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a) } }
1773 *
1774 * which tells FUSE to copy in the requested area and retry the ioctl.
1775 * On the second round, the server has access to the structure and
1776 * from that it can tell what to look for next, so on the invocation,
1777 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
1778 *
1779 * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a)     },
1780 *   { .iov_base = a.buf,       .iov_len = a.buflen             } }
1781 *
1782 * FUSE will copy both struct a and the pointed buffer from the
1783 * process doing the ioctl and retry ioctl with both struct a and the
1784 * buffer.
1785 *
1786 * This time, FUSE server has everything it needs and completes ioctl
1787 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
1788 *
1789 * Copying data out works the same way.
1790 *
1791 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
1792 * automatically initializes in and out iovs by decoding @cmd with
1793 * _IOC_* macros and the server is not allowed to request RETRY.  This
1794 * limits ioctl data transfers to well-formed ioctls and is the forced
1795 * behavior for all FUSE servers.
1796 */
1797long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1798                   unsigned int flags)
1799{
1800        struct fuse_file *ff = file->private_data;
1801        struct fuse_conn *fc = ff->fc;
1802        struct fuse_ioctl_in inarg = {
1803                .fh = ff->fh,
1804                .cmd = cmd,
1805                .arg = arg,
1806                .flags = flags
1807        };
1808        struct fuse_ioctl_out outarg;
1809        struct fuse_req *req = NULL;
1810        struct page **pages = NULL;
1811        struct iovec *iov_page = NULL;
1812        struct iovec *in_iov = NULL, *out_iov = NULL;
1813        unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
1814        size_t in_size, out_size, transferred;
1815        int err;
1816
1817#if BITS_PER_LONG == 32
1818        inarg.flags |= FUSE_IOCTL_32BIT;
1819#else
1820        if (flags & FUSE_IOCTL_COMPAT)
1821                inarg.flags |= FUSE_IOCTL_32BIT;
1822#endif
1823
1824        /* assume all the iovs returned by client always fits in a page */
1825        BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
1826
1827        err = -ENOMEM;
1828        pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
1829        iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
1830        if (!pages || !iov_page)
1831                goto out;
1832
1833        /*
1834         * If restricted, initialize IO parameters as encoded in @cmd.
1835         * RETRY from server is not allowed.
1836         */
1837        if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
1838                struct iovec *iov = iov_page;
1839
1840                iov->iov_base = (void __user *)arg;
1841                iov->iov_len = _IOC_SIZE(cmd);
1842
1843                if (_IOC_DIR(cmd) & _IOC_WRITE) {
1844                        in_iov = iov;
1845                        in_iovs = 1;
1846                }
1847
1848                if (_IOC_DIR(cmd) & _IOC_READ) {
1849                        out_iov = iov;
1850                        out_iovs = 1;
1851                }
1852        }
1853
1854 retry:
1855        inarg.in_size = in_size = iov_length(in_iov, in_iovs);
1856        inarg.out_size = out_size = iov_length(out_iov, out_iovs);
1857
1858        /*
1859         * Out data can be used either for actual out data or iovs,
1860         * make sure there always is at least one page.
1861         */
1862        out_size = max_t(size_t, out_size, PAGE_SIZE);
1863        max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
1864
1865        /* make sure there are enough buffer pages and init request with them */
1866        err = -ENOMEM;
1867        if (max_pages > FUSE_MAX_PAGES_PER_REQ)
1868                goto out;
1869        while (num_pages < max_pages) {
1870                pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
1871                if (!pages[num_pages])
1872                        goto out;
1873                num_pages++;
1874        }
1875
1876        req = fuse_get_req(fc);
1877        if (IS_ERR(req)) {
1878                err = PTR_ERR(req);
1879                req = NULL;
1880                goto out;
1881        }
1882        memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
1883        req->num_pages = num_pages;
1884
1885        /* okay, let's send it to the client */
1886        req->in.h.opcode = FUSE_IOCTL;
1887        req->in.h.nodeid = ff->nodeid;
1888        req->in.numargs = 1;
1889        req->in.args[0].size = sizeof(inarg);
1890        req->in.args[0].value = &inarg;
1891        if (in_size) {
1892                req->in.numargs++;
1893                req->in.args[1].size = in_size;
1894                req->in.argpages = 1;
1895
1896                err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
1897                                           false);
1898                if (err)
1899                        goto out;
1900        }
1901
1902        req->out.numargs = 2;
1903        req->out.args[0].size = sizeof(outarg);
1904        req->out.args[0].value = &outarg;
1905        req->out.args[1].size = out_size;
1906        req->out.argpages = 1;
1907        req->out.argvar = 1;
1908
1909        fuse_request_send(fc, req);
1910        err = req->out.h.error;
1911        transferred = req->out.args[1].size;
1912        fuse_put_request(fc, req);
1913        req = NULL;
1914        if (err)
1915                goto out;
1916
1917        /* did it ask for retry? */
1918        if (outarg.flags & FUSE_IOCTL_RETRY) {
1919                void *vaddr;
1920
1921                /* no retry if in restricted mode */
1922                err = -EIO;
1923                if (!(flags & FUSE_IOCTL_UNRESTRICTED))
1924                        goto out;
1925
1926                in_iovs = outarg.in_iovs;
1927                out_iovs = outarg.out_iovs;
1928
1929                /*
1930                 * Make sure things are in boundary, separate checks
1931                 * are to protect against overflow.
1932                 */
1933                err = -ENOMEM;
1934                if (in_iovs > FUSE_IOCTL_MAX_IOV ||
1935                    out_iovs > FUSE_IOCTL_MAX_IOV ||
1936                    in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
1937                        goto out;
1938
1939                vaddr = kmap_atomic(pages[0]);
1940                err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
1941                                            transferred, in_iovs + out_iovs,
1942                                            (flags & FUSE_IOCTL_COMPAT) != 0);
1943                kunmap_atomic(vaddr);
1944                if (err)
1945                        goto out;
1946
1947                in_iov = iov_page;
1948                out_iov = in_iov + in_iovs;
1949
1950                err = fuse_verify_ioctl_iov(in_iov, in_iovs);
1951                if (err)
1952                        goto out;
1953
1954                err = fuse_verify_ioctl_iov(out_iov, out_iovs);
1955                if (err)
1956                        goto out;
1957
1958                goto retry;
1959        }
1960
1961        err = -EIO;
1962        if (transferred > inarg.out_size)
1963                goto out;
1964
1965        err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
1966 out:
1967        if (req)
1968                fuse_put_request(fc, req);
1969        free_page((unsigned long) iov_page);
1970        while (num_pages)
1971                __free_page(pages[--num_pages]);
1972        kfree(pages);
1973
1974        return err ? err : outarg.result;
1975}
1976EXPORT_SYMBOL_GPL(fuse_do_ioctl);
1977
1978long fuse_ioctl_common(struct file *file, unsigned int cmd,
1979                       unsigned long arg, unsigned int flags)
1980{
1981        struct inode *inode = file->f_dentry->d_inode;
1982        struct fuse_conn *fc = get_fuse_conn(inode);
1983
1984        if (!fuse_allow_task(fc, current))
1985                return -EACCES;
1986
1987        if (is_bad_inode(inode))
1988                return -EIO;
1989
1990        return fuse_do_ioctl(file, cmd, arg, flags);
1991}
1992
1993static long fuse_file_ioctl(struct file *file, unsigned int cmd,
1994                            unsigned long arg)
1995{
1996        return fuse_ioctl_common(file, cmd, arg, 0);
1997}
1998
1999static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2000                                   unsigned long arg)
2001{
2002        return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2003}
2004
2005/*
2006 * All files which have been polled are linked to RB tree
2007 * fuse_conn->polled_files which is indexed by kh.  Walk the tree and
2008 * find the matching one.
2009 */
2010static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2011                                              struct rb_node **parent_out)
2012{
2013        struct rb_node **link = &fc->polled_files.rb_node;
2014        struct rb_node *last = NULL;
2015
2016        while (*link) {
2017                struct fuse_file *ff;
2018
2019                last = *link;
2020                ff = rb_entry(last, struct fuse_file, polled_node);
2021
2022                if (kh < ff->kh)
2023                        link = &last->rb_left;
2024                else if (kh > ff->kh)
2025                        link = &last->rb_right;
2026                else
2027                        return link;
2028        }
2029
2030        if (parent_out)
2031                *parent_out = last;
2032        return link;
2033}
2034
2035/*
2036 * The file is about to be polled.  Make sure it's on the polled_files
2037 * RB tree.  Note that files once added to the polled_files tree are
2038 * not removed before the file is released.  This is because a file
2039 * polled once is likely to be polled again.
2040 */
2041static void fuse_register_polled_file(struct fuse_conn *fc,
2042                                      struct fuse_file *ff)
2043{
2044        spin_lock(&fc->lock);
2045        if (RB_EMPTY_NODE(&ff->polled_node)) {
2046                struct rb_node **link, *parent;
2047
2048                link = fuse_find_polled_node(fc, ff->kh, &parent);
2049                BUG_ON(*link);
2050                rb_link_node(&ff->polled_node, parent, link);
2051                rb_insert_color(&ff->polled_node, &fc->polled_files);
2052        }
2053        spin_unlock(&fc->lock);
2054}
2055
2056unsigned fuse_file_poll(struct file *file, poll_table *wait)
2057{
2058        struct fuse_file *ff = file->private_data;
2059        struct fuse_conn *fc = ff->fc;
2060        struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2061        struct fuse_poll_out outarg;
2062        struct fuse_req *req;
2063        int err;
2064
2065        if (fc->no_poll)
2066                return DEFAULT_POLLMASK;
2067
2068        poll_wait(file, &ff->poll_wait, wait);
2069
2070        /*
2071         * Ask for notification iff there's someone waiting for it.
2072         * The client may ignore the flag and always notify.
2073         */
2074        if (waitqueue_active(&ff->poll_wait)) {
2075                inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2076                fuse_register_polled_file(fc, ff);
2077        }
2078
2079        req = fuse_get_req(fc);
2080        if (IS_ERR(req))
2081                return POLLERR;
2082
2083        req->in.h.opcode = FUSE_POLL;
2084        req->in.h.nodeid = ff->nodeid;
2085        req->in.numargs = 1;
2086        req->in.args[0].size = sizeof(inarg);
2087        req->in.args[0].value = &inarg;
2088        req->out.numargs = 1;
2089        req->out.args[0].size = sizeof(outarg);
2090        req->out.args[0].value = &outarg;
2091        fuse_request_send(fc, req);
2092        err = req->out.h.error;
2093        fuse_put_request(fc, req);
2094
2095        if (!err)
2096                return outarg.revents;
2097        if (err == -ENOSYS) {
2098                fc->no_poll = 1;
2099                return DEFAULT_POLLMASK;
2100        }
2101        return POLLERR;
2102}
2103EXPORT_SYMBOL_GPL(fuse_file_poll);
2104
2105/*
2106 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2107 * wakes up the poll waiters.
2108 */
2109int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2110                            struct fuse_notify_poll_wakeup_out *outarg)
2111{
2112        u64 kh = outarg->kh;
2113        struct rb_node **link;
2114
2115        spin_lock(&fc->lock);
2116
2117        link = fuse_find_polled_node(fc, kh, NULL);
2118        if (*link) {
2119                struct fuse_file *ff;
2120
2121                ff = rb_entry(*link, struct fuse_file, polled_node);
2122                wake_up_interruptible_sync(&ff->poll_wait);
2123        }
2124
2125        spin_unlock(&fc->lock);
2126        return 0;
2127}
2128
2129static ssize_t fuse_loop_dio(struct file *filp, const struct iovec *iov,
2130                             unsigned long nr_segs, loff_t *ppos, int rw)
2131{
2132        const struct iovec *vector = iov;
2133        ssize_t ret = 0;
2134
2135        while (nr_segs > 0) {
2136                void __user *base;
2137                size_t len;
2138                ssize_t nr;
2139
2140                base = vector->iov_base;
2141                len = vector->iov_len;
2142                vector++;
2143                nr_segs--;
2144
2145                if (rw == WRITE)
2146                        nr = __fuse_direct_write(filp, base, len, ppos);
2147                else
2148                        nr = fuse_direct_read(filp, base, len, ppos);
2149
2150                if (nr < 0) {
2151                        if (!ret)
2152                                ret = nr;
2153                        break;
2154                }
2155                ret += nr;
2156                if (nr != len)
2157                        break;
2158        }
2159
2160        return ret;
2161}
2162
2163
2164static ssize_t
2165fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
2166                        loff_t offset, unsigned long nr_segs)
2167{
2168        ssize_t ret = 0;
2169        struct file *file = NULL;
2170        loff_t pos = 0;
2171
2172        file = iocb->ki_filp;
2173        pos = offset;
2174
2175        ret = fuse_loop_dio(file, iov, nr_segs, &pos, rw);
2176
2177        return ret;
2178}
2179
2180long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2181                            loff_t length)
2182{
2183        struct fuse_file *ff = file->private_data;
2184        struct fuse_conn *fc = ff->fc;
2185        struct fuse_req *req;
2186        struct fuse_fallocate_in inarg = {
2187                .fh = ff->fh,
2188                .offset = offset,
2189                .length = length,
2190                .mode = mode
2191        };
2192        int err;
2193
2194        if (fc->no_fallocate)
2195                return -EOPNOTSUPP;
2196
2197        req = fuse_get_req(fc);
2198        if (IS_ERR(req))
2199                return PTR_ERR(req);
2200
2201        req->in.h.opcode = FUSE_FALLOCATE;
2202        req->in.h.nodeid = ff->nodeid;
2203        req->in.numargs = 1;
2204        req->in.args[0].size = sizeof(inarg);
2205        req->in.args[0].value = &inarg;
2206        fuse_request_send(fc, req);
2207        err = req->out.h.error;
2208        if (err == -ENOSYS) {
2209                fc->no_fallocate = 1;
2210                err = -EOPNOTSUPP;
2211        }
2212        fuse_put_request(fc, req);
2213
2214        return err;
2215}
2216EXPORT_SYMBOL_GPL(fuse_file_fallocate);
2217
2218static const struct file_operations fuse_file_operations = {
2219        .llseek         = fuse_file_llseek,
2220        .read           = do_sync_read,
2221        .aio_read       = fuse_file_aio_read,
2222        .write          = do_sync_write,
2223        .aio_write      = fuse_file_aio_write,
2224        .mmap           = fuse_file_mmap,
2225        .open           = fuse_open,
2226        .flush          = fuse_flush,
2227        .release        = fuse_release,
2228        .fsync          = fuse_fsync,
2229        .lock           = fuse_file_lock,
2230        .flock          = fuse_file_flock,
2231        .splice_read    = generic_file_splice_read,
2232        .unlocked_ioctl = fuse_file_ioctl,
2233        .compat_ioctl   = fuse_file_compat_ioctl,
2234        .poll           = fuse_file_poll,
2235        .fallocate      = fuse_file_fallocate,
2236};
2237
2238static const struct file_operations fuse_direct_io_file_operations = {
2239        .llseek         = fuse_file_llseek,
2240        .read           = fuse_direct_read,
2241        .write          = fuse_direct_write,
2242        .mmap           = fuse_direct_mmap,
2243        .open           = fuse_open,
2244        .flush          = fuse_flush,
2245        .release        = fuse_release,
2246        .fsync          = fuse_fsync,
2247        .lock           = fuse_file_lock,
2248        .flock          = fuse_file_flock,
2249        .unlocked_ioctl = fuse_file_ioctl,
2250        .compat_ioctl   = fuse_file_compat_ioctl,
2251        .poll           = fuse_file_poll,
2252        .fallocate      = fuse_file_fallocate,
2253        /* no splice_read */
2254};
2255
2256static const struct address_space_operations fuse_file_aops  = {
2257        .readpage       = fuse_readpage,
2258        .writepage      = fuse_writepage,
2259        .launder_page   = fuse_launder_page,
2260        .readpages      = fuse_readpages,
2261        .set_page_dirty = __set_page_dirty_nobuffers,
2262        .bmap           = fuse_bmap,
2263        .direct_IO      = fuse_direct_IO,
2264};
2265
2266void fuse_init_file_inode(struct inode *inode)
2267{
2268        inode->i_fop = &fuse_file_operations;
2269        inode->i_data.a_ops = &fuse_file_aops;
2270}
2271
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