fs/fuse/file.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/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
  18 static const struct file_operations fuse_direct_io_file_operations;
  19
  20 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
  21                           int opcode, struct fuse_open_out *outargp)
  22 {
  23         struct fuse_open_in inarg;
  24         struct fuse_req *req;
  25         int err;
  26
  27         req = fuse_get_req(fc);
  28         if (IS_ERR(req))
  29                 return PTR_ERR(req);
  30
  31         memset(&inarg, 0, sizeof(inarg));
  32         inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
  33         if (!fc->atomic_o_trunc)
  34                 inarg.flags &= ~O_TRUNC;
  35         req->in.h.opcode = opcode;
  36         req->in.h.nodeid = nodeid;
  37         req->in.numargs = 1;
  38         req->in.args[0].size = sizeof(inarg);
  39         req->in.args[0].value = &inarg;
  40         req->out.numargs = 1;
  41         req->out.args[0].size = sizeof(*outargp);
  42         req->out.args[0].value = outargp;
  43         fuse_request_send(fc, req);
  44         err = req->out.h.error;
  45         fuse_put_request(fc, req);
  46
  47         return err;
  48 }
  49
  50 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
  51 {
  52         struct fuse_file *ff;
  53
  54         ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
  55         if (unlikely(!ff))
  56                 return NULL;
  57
  58         ff->fc = fc;
  59         ff->reserved_req = fuse_request_alloc();
  60         if (unlikely(!ff->reserved_req)) {
  61                 kfree(ff);
  62                 return NULL;
  63         }
  64
  65         INIT_LIST_HEAD(&ff->write_entry);
  66         atomic_set(&ff->count, 0);
  67         RB_CLEAR_NODE(&ff->polled_node);
  68         init_waitqueue_head(&ff->poll_wait);
  69
  70         spin_lock(&fc->lock);
  71         ff->kh = ++fc->khctr;
  72         spin_unlock(&fc->lock);
  73
  74         return ff;
  75 }
  76
  77 void fuse_file_free(struct fuse_file *ff)
  78 {
  79         fuse_request_free(ff->reserved_req);
  80         kfree(ff);
  81 }
  82
  83 struct fuse_file *fuse_file_get(struct fuse_file *ff)
  84 {
  85         atomic_inc(&ff->count);
  86         return ff;
  87 }
  88
  89 static void fuse_release_async(struct work_struct *work)
  90 {
  91         struct fuse_req *req;
  92         struct fuse_conn *fc;
  93         struct path path;
  94
  95         req = container_of(work, struct fuse_req, misc.release.work);
  96         path = req->misc.release.path;
  97         fc = get_fuse_conn(path.dentry->d_inode);
  98
  99         fuse_put_request(fc, req);
 100         path_put(&path);
 101 }
 102
 103 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
 104 {
 105         if (fc->destroy_req) {
 106                 /*
 107                  * If this is a fuseblk mount, then it's possible that
 108                  * releasing the path will result in releasing the
 109                  * super block and sending the DESTROY request.  If
 110                  * the server is single threaded, this would hang.
 111                  * For this reason do the path_put() in a separate
 112                  * thread.
 113                  */
 114                 atomic_inc(&req->count);
 115                 INIT_WORK(&req->misc.release.work, fuse_release_async);
 116                 schedule_work(&req->misc.release.work);
 117         } else {
 118                 path_put(&req->misc.release.path);
 119         }
 120 }
 121
 122 static void fuse_file_put(struct fuse_file *ff, bool sync)
 123 {
 124         if (atomic_dec_and_test(&ff->count)) {
 125                 struct fuse_req *req = ff->reserved_req;
 126
 127                 if (sync) {
 128                         fuse_request_send(ff->fc, req);
 129                         path_put(&req->misc.release.path);
 130                         fuse_put_request(ff->fc, req);
 131                 } else {
 132                         req->end = fuse_release_end;
 133                         fuse_request_send_background(ff->fc, req);
 134                 }
 135                 kfree(ff);
 136         }
 137 }
 138
 139 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 140                  bool isdir)
 141 {
 142         struct fuse_open_out outarg;
 143         struct fuse_file *ff;
 144         int err;
 145         int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
 146
 147         ff = fuse_file_alloc(fc);
 148         if (!ff)
 149                 return -ENOMEM;
 150
 151         err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
 152         if (err) {
 153                 fuse_file_free(ff);
 154                 return err;
 155         }
 156
 157         if (isdir)
 158                 outarg.open_flags &= ~FOPEN_DIRECT_IO;
 159
 160         ff->fh = outarg.fh;
 161         ff->nodeid = nodeid;
 162         ff->open_flags = outarg.open_flags;
 163         file->private_data = fuse_file_get(ff);
 164
 165         return 0;
 166 }
 167 EXPORT_SYMBOL_GPL(fuse_do_open);
 168
 169 void fuse_finish_open(struct inode *inode, struct file *file)
 170 {
 171         struct fuse_file *ff = file->private_data;
 172         struct fuse_conn *fc = get_fuse_conn(inode);
 173
 174         if (ff->open_flags & FOPEN_DIRECT_IO)
 175                 file->f_op = &fuse_direct_io_file_operations;
 176         if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 177                 invalidate_inode_pages2(inode->i_mapping);
 178         if (ff->open_flags & FOPEN_NONSEEKABLE)
 179                 nonseekable_open(inode, file);
 180         if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
 181                 struct fuse_inode *fi = get_fuse_inode(inode);
 182
 183                 spin_lock(&fc->lock);
 184                 fi->attr_version = ++fc->attr_version;
 185                 i_size_write(inode, 0);
 186                 spin_unlock(&fc->lock);
 187                 fuse_invalidate_attr(inode);
 188         }
 189 }
 190
 191 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 192 {
 193         struct fuse_conn *fc = get_fuse_conn(inode);
 194         int err;
 195
 196         /* VFS checks this, but only _after_ ->open() */
 197         if (file->f_flags & O_DIRECT)
 198                 return -EINVAL;
 199
 200         err = generic_file_open(inode, file);
 201         if (err)
 202                 return err;
 203
 204         err = fuse_do_open(fc, get_node_id(inode), file, isdir);
 205         if (err)
 206                 return err;
 207
 208         fuse_finish_open(inode, file);
 209
 210         return 0;
 211 }
 212
 213 static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
 214 {
 215         struct fuse_conn *fc = ff->fc;
 216         struct fuse_req *req = ff->reserved_req;
 217         struct fuse_release_in *inarg = &req->misc.release.in;
 218
 219         spin_lock(&fc->lock);
 220         list_del(&ff->write_entry);
 221         if (!RB_EMPTY_NODE(&ff->polled_node))
 222                 rb_erase(&ff->polled_node, &fc->polled_files);
 223         spin_unlock(&fc->lock);
 224
 225         wake_up_interruptible_all(&ff->poll_wait);
 226
 227         inarg->fh = ff->fh;
 228         inarg->flags = flags;
 229         req->in.h.opcode = opcode;
 230         req->in.h.nodeid = ff->nodeid;
 231         req->in.numargs = 1;
 232         req->in.args[0].size = sizeof(struct fuse_release_in);
 233         req->in.args[0].value = inarg;
 234 }
 235
 236 void fuse_release_common(struct file *file, int opcode)
 237 {
 238         struct fuse_file *ff;
 239         struct fuse_req *req;
 240
 241         ff = file->private_data;
 242         if (unlikely(!ff))
 243                 return;
 244
 245         req = ff->reserved_req;
 246         fuse_prepare_release(ff, file->f_flags, opcode);
 247
 248         /* Hold vfsmount and dentry until release is finished */
 249         path_get(&file->f_path);
 250         req->misc.release.path = file->f_path;
 251
 252         /*
 253          * Normally this will send the RELEASE request, however if
 254          * some asynchronous READ or WRITE requests are outstanding,
 255          * the sending will be delayed.
 256          *
 257          * Make the release synchronous if this is a fuseblk mount,
 258          * synchronous RELEASE is allowed (and desirable) in this case
 259          * because the server can be trusted not to screw up.
 260          */
 261         fuse_file_put(ff, ff->fc->destroy_req != NULL);
 262 }
 263
 264 static int fuse_open(struct inode *inode, struct file *file)
 265 {
 266         return fuse_open_common(inode, file, false);
 267 }
 268
 269 static int fuse_release(struct inode *inode, struct file *file)
 270 {
 271         fuse_release_common(file, FUSE_RELEASE);
 272
 273         /* return value is ignored by VFS */
 274         return 0;
 275 }
 276
 277 void fuse_sync_release(struct fuse_file *ff, int flags)
 278 {
 279         WARN_ON(atomic_read(&ff->count) > 1);
 280         fuse_prepare_release(ff, flags, FUSE_RELEASE);
 281         ff->reserved_req->force = 1;
 282         fuse_request_send(ff->fc, ff->reserved_req);
 283         fuse_put_request(ff->fc, ff->reserved_req);
 284         kfree(ff);
 285 }
 286 EXPORT_SYMBOL_GPL(fuse_sync_release);
 287
 288 /*
 289  * Scramble the ID space with XTEA, so that the value of the files_struct
 290  * pointer is not exposed to userspace.
 291  */
 292 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 293 {
 294         u32 *k = fc->scramble_key;
 295         u64 v = (unsigned long) id;
 296         u32 v0 = v;
 297         u32 v1 = v >> 32;
 298         u32 sum = 0;
 299         int i;
 300
 301         for (i = 0; i < 32; i++) {
 302                 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
 303                 sum += 0x9E3779B9;
 304                 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
 305         }
 306
 307         return (u64) v0 + ((u64) v1 << 32);
 308 }
 309
 310 /*
 311  * Check if page is under writeback
 312  *
 313  * This is currently done by walking the list of writepage requests
 314  * for the inode, which can be pretty inefficient.
 315  */
 316 static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
 317 {
 318         struct fuse_conn *fc = get_fuse_conn(inode);
 319         struct fuse_inode *fi = get_fuse_inode(inode);
 320         struct fuse_req *req;
 321         bool found = false;
 322
 323         spin_lock(&fc->lock);
 324         list_for_each_entry(req, &fi->writepages, writepages_entry) {
 325                 pgoff_t curr_index;
 326
 327                 BUG_ON(req->inode != inode);
 328                 curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
 329                 if (curr_index == index) {
 330                         found = true;
 331                         break;
 332                 }
 333         }
 334         spin_unlock(&fc->lock);
 335
 336         return found;
 337 }
 338
 339 /*
 340  * Wait for page writeback to be completed.
 341  *
 342  * Since fuse doesn't rely on the VM writeback tracking, this has to
 343  * use some other means.
 344  */
 345 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
 346 {
 347         struct fuse_inode *fi = get_fuse_inode(inode);
 348
 349         wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
 350         return 0;
 351 }
 352
 353 static int fuse_flush(struct file *file, fl_owner_t id)
 354 {
 355         struct inode *inode = file->f_path.dentry->d_inode;
 356         struct fuse_conn *fc = get_fuse_conn(inode);
 357         struct fuse_file *ff = file->private_data;
 358         struct fuse_req *req;
 359         struct fuse_flush_in inarg;
 360         int err;
 361
 362         if (is_bad_inode(inode))
 363                 return -EIO;
 364
 365         if (fc->no_flush)
 366                 return 0;
 367
 368         req = fuse_get_req_nofail(fc, file);
 369         memset(&inarg, 0, sizeof(inarg));
 370         inarg.fh = ff->fh;
 371         inarg.lock_owner = fuse_lock_owner_id(fc, id);
 372         req->in.h.opcode = FUSE_FLUSH;
 373         req->in.h.nodeid = get_node_id(inode);
 374         req->in.numargs = 1;
 375         req->in.args[0].size = sizeof(inarg);
 376         req->in.args[0].value = &inarg;
 377         req->force = 1;
 378         fuse_request_send(fc, req);
 379         err = req->out.h.error;
 380         fuse_put_request(fc, req);
 381         if (err == -ENOSYS) {
 382                 fc->no_flush = 1;
 383                 err = 0;
 384         }
 385         return err;
 386 }
 387
 388 /*
 389  * Wait for all pending writepages on the inode to finish.
 390  *
 391  * This is currently done by blocking further writes with FUSE_NOWRITE
 392  * and waiting for all sent writes to complete.
 393  *
 394  * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
 395  * could conflict with truncation.
 396  */
 397 static void fuse_sync_writes(struct inode *inode)
 398 {
 399         fuse_set_nowrite(inode);
 400         fuse_release_nowrite(inode);
 401 }
 402
 403 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 404                       int datasync, int isdir)
 405 {
 406         struct inode *inode = file->f_mapping->host;
 407         struct fuse_conn *fc = get_fuse_conn(inode);
 408         struct fuse_file *ff = file->private_data;
 409         struct fuse_req *req;
 410         struct fuse_fsync_in inarg;
 411         int err;
 412
 413         if (is_bad_inode(inode))
 414                 return -EIO;
 415
 416         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 417         if (err)
 418                 return err;
 419
 420         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 421                 return 0;
 422
 423         mutex_lock(&inode->i_mutex);
 424
 425         /*
 426          * Start writeback against all dirty pages of the inode, then
 427          * wait for all outstanding writes, before sending the FSYNC
 428          * request.
 429          */
 430         err = write_inode_now(inode, 0);
 431         if (err)
 432                 goto out;
 433
 434         fuse_sync_writes(inode);
 435
 436         req = fuse_get_req(fc);
 437         if (IS_ERR(req)) {
 438                 err = PTR_ERR(req);
 439                 goto out;
 440         }
 441
 442         memset(&inarg, 0, sizeof(inarg));
 443         inarg.fh = ff->fh;
 444         inarg.fsync_flags = datasync ? 1 : 0;
 445         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 446         req->in.h.nodeid = get_node_id(inode);
 447         req->in.numargs = 1;
 448         req->in.args[0].size = sizeof(inarg);
 449         req->in.args[0].value = &inarg;
 450         fuse_request_send(fc, req);
 451         err = req->out.h.error;
 452         fuse_put_request(fc, req);
 453         if (err == -ENOSYS) {
 454                 if (isdir)
 455                         fc->no_fsyncdir = 1;
 456                 else
 457                         fc->no_fsync = 1;
 458                 err = 0;
 459         }
 460 out:
 461         mutex_unlock(&inode->i_mutex);
 462         return err;
 463 }
 464
 465 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
 466                       int datasync)
 467 {
 468         return fuse_fsync_common(file, start, end, datasync, 0);
 469 }
 470
 471 void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
 472                     size_t count, int opcode)
 473 {
 474         struct fuse_read_in *inarg = &req->misc.read.in;
 475         struct fuse_file *ff = file->private_data;
 476
 477         inarg->fh = ff->fh;
 478         inarg->offset = pos;
 479         inarg->size = count;
 480         inarg->flags = file->f_flags;
 481         req->in.h.opcode = opcode;
 482         req->in.h.nodeid = ff->nodeid;
 483         req->in.numargs = 1;
 484         req->in.args[0].size = sizeof(struct fuse_read_in);
 485         req->in.args[0].value = inarg;
 486         req->out.argvar = 1;
 487         req->out.numargs = 1;
 488         req->out.args[0].size = count;
 489 }
 490
 491 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 492                              loff_t pos, size_t count, fl_owner_t owner)
 493 {
 494         struct fuse_file *ff = file->private_data;
 495         struct fuse_conn *fc = ff->fc;
 496
 497         fuse_read_fill(req, file, pos, count, FUSE_READ);
 498         if (owner != NULL) {
 499                 struct fuse_read_in *inarg = &req->misc.read.in;
 500
 501                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
 502                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 503         }
 504         fuse_request_send(fc, req);
 505         return req->out.args[0].size;
 506 }
 507
 508 static void fuse_read_update_size(struct inode *inode, loff_t size,
 509                                   u64 attr_ver)
 510 {
 511         struct fuse_conn *fc = get_fuse_conn(inode);
 512         struct fuse_inode *fi = get_fuse_inode(inode);
 513
 514         spin_lock(&fc->lock);
 515         if (attr_ver == fi->attr_version && size < inode->i_size) {
 516                 fi->attr_version = ++fc->attr_version;
 517                 i_size_write(inode, size);
 518         }
 519         spin_unlock(&fc->lock);
 520 }
 521
 522 static int fuse_readpage(struct file *file, struct page *page)
 523 {
 524         struct inode *inode = page->mapping->host;
 525         struct fuse_conn *fc = get_fuse_conn(inode);
 526         struct fuse_req *req;
 527         size_t num_read;
 528         loff_t pos = page_offset(page);
 529         size_t count = PAGE_CACHE_SIZE;
 530         u64 attr_ver;
 531         int err;
 532
 533         err = -EIO;
 534         if (is_bad_inode(inode))
 535                 goto out;
 536
 537         /*
 538          * Page writeback can extend beyond the lifetime of the
 539          * page-cache page, so make sure we read a properly synced
 540          * page.
 541          */
 542         fuse_wait_on_page_writeback(inode, page->index);
 543
 544         req = fuse_get_req(fc);
 545         err = PTR_ERR(req);
 546         if (IS_ERR(req))
 547                 goto out;
 548
 549         attr_ver = fuse_get_attr_version(fc);
 550
 551         req->out.page_zeroing = 1;
 552         req->out.argpages = 1;
 553         req->num_pages = 1;
 554         req->pages[0] = page;
 555         num_read = fuse_send_read(req, file, pos, count, NULL);
 556         err = req->out.h.error;
 557         fuse_put_request(fc, req);
 558
 559         if (!err) {
 560                 /*
 561                  * Short read means EOF.  If file size is larger, truncate it
 562                  */
 563                 if (num_read < count)
 564                         fuse_read_update_size(inode, pos + num_read, attr_ver);
 565
 566                 SetPageUptodate(page);
 567         }
 568
 569         fuse_invalidate_attr(inode); /* atime changed */
 570  out:
 571         unlock_page(page);
 572         return err;
 573 }
 574
 575 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 576 {
 577         int i;
 578         size_t count = req->misc.read.in.size;
 579         size_t num_read = req->out.args[0].size;
 580         struct address_space *mapping = NULL;
 581
 582         for (i = 0; mapping == NULL && i < req->num_pages; i++)
 583                 mapping = req->pages[i]->mapping;
 584
 585         if (mapping) {
 586                 struct inode *inode = mapping->host;
 587
 588                 /*
 589                  * Short read means EOF. If file size is larger, truncate it
 590                  */
 591                 if (!req->out.h.error && num_read < count) {
 592                         loff_t pos;
 593
 594                         pos = page_offset(req->pages[0]) + num_read;
 595                         fuse_read_update_size(inode, pos,
 596                                               req->misc.read.attr_ver);
 597                 }
 598                 fuse_invalidate_attr(inode); /* atime changed */
 599         }
 600
 601         for (i = 0; i < req->num_pages; i++) {
 602                 struct page *page = req->pages[i];
 603                 if (!req->out.h.error)
 604                         SetPageUptodate(page);
 605                 else
 606                         SetPageError(page);
 607                 unlock_page(page);
 608                 page_cache_release(page);
 609         }
 610         if (req->ff)
 611                 fuse_file_put(req->ff, false);
 612 }
 613
 614 static void fuse_send_readpages(struct fuse_req *req, struct file *file)
 615 {
 616         struct fuse_file *ff = file->private_data;
 617         struct fuse_conn *fc = ff->fc;
 618         loff_t pos = page_offset(req->pages[0]);
 619         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 620
 621         req->out.argpages = 1;
 622         req->out.page_zeroing = 1;
 623         req->out.page_replace = 1;
 624         fuse_read_fill(req, file, pos, count, FUSE_READ);
 625         req->misc.read.attr_ver = fuse_get_attr_version(fc);
 626         if (fc->async_read) {
 627                 req->ff = fuse_file_get(ff);
 628                 req->end = fuse_readpages_end;
 629                 fuse_request_send_background(fc, req);
 630         } else {
 631                 fuse_request_send(fc, req);
 632                 fuse_readpages_end(fc, req);
 633                 fuse_put_request(fc, req);
 634         }
 635 }
 636
 637 struct fuse_fill_data {
 638         struct fuse_req *req;
 639         struct file *file;
 640         struct inode *inode;
 641 };
 642
 643 static int fuse_readpages_fill(void *_data, struct page *page)
 644 {
 645         struct fuse_fill_data *data = _data;
 646         struct fuse_req *req = data->req;
 647         struct inode *inode = data->inode;
 648         struct fuse_conn *fc = get_fuse_conn(inode);
 649
 650         fuse_wait_on_page_writeback(inode, page->index);
 651
 652         if (req->num_pages &&
 653             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 654              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 655              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 656                 fuse_send_readpages(req, data->file);
 657                 data->req = req = fuse_get_req(fc);
 658                 if (IS_ERR(req)) {
 659                         unlock_page(page);
 660                         return PTR_ERR(req);
 661                 }
 662         }
 663         page_cache_get(page);
 664         req->pages[req->num_pages] = page;
 665         req->num_pages++;
 666         return 0;
 667 }
 668
 669 static int fuse_readpages(struct file *file, struct address_space *mapping,
 670                           struct list_head *pages, unsigned nr_pages)
 671 {
 672         struct inode *inode = mapping->host;
 673         struct fuse_conn *fc = get_fuse_conn(inode);
 674         struct fuse_fill_data data;
 675         int err;
 676
 677         err = -EIO;
 678         if (is_bad_inode(inode))
 679                 goto out;
 680
 681         data.file = file;
 682         data.inode = inode;
 683         data.req = fuse_get_req(fc);
 684         err = PTR_ERR(data.req);
 685         if (IS_ERR(data.req))
 686                 goto out;
 687
 688         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 689         if (!err) {
 690                 if (data.req->num_pages)
 691                         fuse_send_readpages(data.req, file);
 692                 else
 693                         fuse_put_request(fc, data.req);
 694         }
 695 out:
 696         return err;
 697 }
 698
 699 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 700                                   unsigned long nr_segs, loff_t pos)
 701 {
 702         struct inode *inode = iocb->ki_filp->f_mapping->host;
 703
 704         if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
 705                 int err;
 706                 /*
 707                  * If trying to read past EOF, make sure the i_size
 708                  * attribute is up-to-date.
 709                  */
 710                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 711                 if (err)
 712                         return err;
 713         }
 714
 715         return generic_file_aio_read(iocb, iov, nr_segs, pos);
 716 }
 717
 718 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 719                             loff_t pos, size_t count)
 720 {
 721         struct fuse_write_in *inarg = &req->misc.write.in;
 722         struct fuse_write_out *outarg = &req->misc.write.out;
 723
 724         inarg->fh = ff->fh;
 725         inarg->offset = pos;
 726         inarg->size = count;
 727         req->in.h.opcode = FUSE_WRITE;
 728         req->in.h.nodeid = ff->nodeid;
 729         req->in.numargs = 2;
 730         if (ff->fc->minor < 9)
 731                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 732         else
 733                 req->in.args[0].size = sizeof(struct fuse_write_in);
 734         req->in.args[0].value = inarg;
 735         req->in.args[1].size = count;
 736         req->out.numargs = 1;
 737         req->out.args[0].size = sizeof(struct fuse_write_out);
 738         req->out.args[0].value = outarg;
 739 }
 740
 741 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 742                               loff_t pos, size_t count, fl_owner_t owner)
 743 {
 744         struct fuse_file *ff = file->private_data;
 745         struct fuse_conn *fc = ff->fc;
 746         struct fuse_write_in *inarg = &req->misc.write.in;
 747
 748         fuse_write_fill(req, ff, pos, count);
 749         inarg->flags = file->f_flags;
 750         if (owner != NULL) {
 751                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 752                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 753         }
 754         fuse_request_send(fc, req);
 755         return req->misc.write.out.size;
 756 }
 757
 758 static int fuse_write_begin(struct file *file, struct address_space *mapping,
 759                         loff_t pos, unsigned len, unsigned flags,
 760                         struct page **pagep, void **fsdata)
 761 {
 762         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 763
 764         *pagep = grab_cache_page_write_begin(mapping, index, flags);
 765         if (!*pagep)
 766                 return -ENOMEM;
 767         return 0;
 768 }
 769
 770 void fuse_write_update_size(struct inode *inode, loff_t pos)
 771 {
 772         struct fuse_conn *fc = get_fuse_conn(inode);
 773         struct fuse_inode *fi = get_fuse_inode(inode);
 774
 775         spin_lock(&fc->lock);
 776         fi->attr_version = ++fc->attr_version;
 777         if (pos > inode->i_size)
 778                 i_size_write(inode, pos);
 779         spin_unlock(&fc->lock);
 780 }
 781
 782 static int fuse_buffered_write(struct file *file, struct inode *inode,
 783                                loff_t pos, unsigned count, struct page *page)
 784 {
 785         int err;
 786         size_t nres;
 787         struct fuse_conn *fc = get_fuse_conn(inode);
 788         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 789         struct fuse_req *req;
 790
 791         if (is_bad_inode(inode))
 792                 return -EIO;
 793
 794         /*
 795          * Make sure writepages on the same page are not mixed up with
 796          * plain writes.
 797          */
 798         fuse_wait_on_page_writeback(inode, page->index);
 799
 800         req = fuse_get_req(fc);
 801         if (IS_ERR(req))
 802                 return PTR_ERR(req);
 803
 804         req->in.argpages = 1;
 805         req->num_pages = 1;
 806         req->pages[0] = page;
 807         req->page_offset = offset;
 808         nres = fuse_send_write(req, file, pos, count, NULL);
 809         err = req->out.h.error;
 810         fuse_put_request(fc, req);
 811         if (!err && !nres)
 812                 err = -EIO;
 813         if (!err) {
 814                 pos += nres;
 815                 fuse_write_update_size(inode, pos);
 816                 if (count == PAGE_CACHE_SIZE)
 817                         SetPageUptodate(page);
 818         }
 819         fuse_invalidate_attr(inode);
 820         return err ? err : nres;
 821 }
 822
 823 static int fuse_write_end(struct file *file, struct address_space *mapping,
 824                         loff_t pos, unsigned len, unsigned copied,
 825                         struct page *page, void *fsdata)
 826 {
 827         struct inode *inode = mapping->host;
 828         int res = 0;
 829
 830         if (copied)
 831                 res = fuse_buffered_write(file, inode, pos, copied, page);
 832
 833         unlock_page(page);
 834         page_cache_release(page);
 835         return res;
 836 }
 837
 838 static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
 839                                     struct inode *inode, loff_t pos,
 840                                     size_t count)
 841 {
 842         size_t res;
 843         unsigned offset;
 844         unsigned i;
 845
 846         for (i = 0; i < req->num_pages; i++)
 847                 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
 848
 849         res = fuse_send_write(req, file, pos, count, NULL);
 850
 851         offset = req->page_offset;
 852         count = res;
 853         for (i = 0; i < req->num_pages; i++) {
 854                 struct page *page = req->pages[i];
 855
 856                 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
 857                         SetPageUptodate(page);
 858
 859                 if (count > PAGE_CACHE_SIZE - offset)
 860                         count -= PAGE_CACHE_SIZE - offset;
 861                 else
 862                         count = 0;
 863                 offset = 0;
 864
 865                 unlock_page(page);
 866                 page_cache_release(page);
 867         }
 868
 869         return res;
 870 }
 871
 872 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 873                                struct address_space *mapping,
 874                                struct iov_iter *ii, loff_t pos)
 875 {
 876         struct fuse_conn *fc = get_fuse_conn(mapping->host);
 877         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 878         size_t count = 0;
 879         int err;
 880
 881         req->in.argpages = 1;
 882         req->page_offset = offset;
 883
 884         do {
 885                 size_t tmp;
 886                 struct page *page;
 887                 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 888                 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
 889                                      iov_iter_count(ii));
 890
 891                 bytes = min_t(size_t, bytes, fc->max_write - count);
 892
 893  again:
 894                 err = -EFAULT;
 895                 if (iov_iter_fault_in_readable(ii, bytes))
 896                         break;
 897
 898                 err = -ENOMEM;
 899                 page = grab_cache_page_write_begin(mapping, index, 0);
 900                 if (!page)
 901                         break;
 902
 903                 if (mapping_writably_mapped(mapping))
 904                         flush_dcache_page(page);
 905
 906                 pagefault_disable();
 907                 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
 908                 pagefault_enable();
 909                 flush_dcache_page(page);
 910
 911                 if (!tmp) {
 912                         unlock_page(page);
 913                         page_cache_release(page);
 914                         bytes = min(bytes, iov_iter_single_seg_count(ii));
 915                         goto again;
 916                 }
 917
 918                 err = 0;
 919                 req->pages[req->num_pages] = page;
 920                 req->num_pages++;
 921
 922                 iov_iter_advance(ii, tmp);
 923                 count += tmp;
 924                 pos += tmp;
 925                 offset += tmp;
 926                 if (offset == PAGE_CACHE_SIZE)
 927                         offset = 0;
 928
 929                 if (!fc->big_writes)
 930                         break;
 931         } while (iov_iter_count(ii) && count < fc->max_write &&
 932                  req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
 933
 934         return count > 0 ? count : err;
 935 }
 936
 937 static ssize_t fuse_perform_write(struct file *file,
 938                                   struct address_space *mapping,
 939                                   struct iov_iter *ii, loff_t pos)
 940 {
 941         struct inode *inode = mapping->host;
 942         struct fuse_conn *fc = get_fuse_conn(inode);
 943         int err = 0;
 944         ssize_t res = 0;
 945
 946         if (is_bad_inode(inode))
 947                 return -EIO;
 948
 949         do {
 950                 struct fuse_req *req;
 951                 ssize_t count;
 952
 953                 req = fuse_get_req(fc);
 954                 if (IS_ERR(req)) {
 955                         err = PTR_ERR(req);
 956                         break;
 957                 }
 958
 959                 count = fuse_fill_write_pages(req, mapping, ii, pos);
 960                 if (count <= 0) {
 961                         err = count;
 962                 } else {
 963                         size_t num_written;
 964
 965                         num_written = fuse_send_write_pages(req, file, inode,
 966                                                             pos, count);
 967                         err = req->out.h.error;
 968                         if (!err) {
 969                                 res += num_written;
 970                                 pos += num_written;
 971
 972                                 /* break out of the loop on short write */
 973                                 if (num_written != count)
 974                                         err = -EIO;
 975                         }
 976                 }
 977                 fuse_put_request(fc, req);
 978         } while (!err && iov_iter_count(ii));
 979
 980         if (res > 0)
 981                 fuse_write_update_size(inode, pos);
 982
 983         fuse_invalidate_attr(inode);
 984
 985         return res > 0 ? res : err;
 986 }
 987
 988 static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 989                                    unsigned long nr_segs, loff_t pos)
 990 {
 991         struct file *file = iocb->ki_filp;
 992         struct address_space *mapping = file->f_mapping;
 993         size_t count = 0;
 994         ssize_t written = 0;
 995         struct inode *inode = mapping->host;
 996         ssize_t err;
 997         struct iov_iter i;
 998
 999         WARN_ON(iocb->ki_pos != pos);
1000
1001         err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
1002         if (err)
1003                 return err;
1004
1005         mutex_lock(&inode->i_mutex);
1006         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
1007
1008         /* We can write back this queue in page reclaim */
1009         current->backing_dev_info = mapping->backing_dev_info;
1010
1011         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1012         if (err)
1013                 goto out;
1014
1015         if (count == 0)
1016                 goto out;
1017
1018         err = file_remove_suid(file);
1019         if (err)
1020                 goto out;
1021
1022         file_update_time(file);
1023
1024         iov_iter_init(&i, iov, nr_segs, count, 0);
1025         written = fuse_perform_write(file, mapping, &i, pos);
1026         if (written >= 0)
1027                 iocb->ki_pos = pos + written;
1028
1029 out:
1030         current->backing_dev_info = NULL;
1031         mutex_unlock(&inode->i_mutex);
1032
1033         return written ? written : err;
1034 }
1035
1036 static void fuse_release_user_pages(struct fuse_req *req, int write)
1037 {
1038         unsigned i;
1039
1040         for (i = 0; i < req->num_pages; i++) {
1041                 struct page *page = req->pages[i];
1042                 if (write)
1043                         set_page_dirty_lock(page);
1044                 put_page(page);
1045         }
1046 }
1047
1048 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
1049                                size_t *nbytesp, int write)
1050 {
1051         size_t nbytes = *nbytesp;
1052         unsigned long user_addr = (unsigned long) buf;
1053         unsigned offset = user_addr & ~PAGE_MASK;
1054         int npages;
1055
1056         /* Special case for kernel I/O: can copy directly into the buffer */
1057         if (segment_eq(get_fs(), KERNEL_DS)) {
1058                 if (write)
1059                         req->in.args[1].value = (void *) user_addr;
1060                 else
1061                         req->out.args[0].value = (void *) user_addr;
1062
1063                 return 0;
1064         }
1065
1066         nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
1067         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1068         npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
1069         npages = get_user_pages_fast(user_addr, npages, !write, req->pages);
1070         if (npages < 0)
1071                 return npages;
1072
1073         req->num_pages = npages;
1074         req->page_offset = offset;
1075
1076         if (write)
1077                 req->in.argpages = 1;
1078         else
1079                 req->out.argpages = 1;
1080
1081         nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
1082         *nbytesp = min(*nbytesp, nbytes);
1083
1084         return 0;
1085 }
1086
1087 ssize_t fuse_direct_io(struct file *file, const char __user *buf,
1088                        size_t count, loff_t *ppos, int write)
1089 {
1090         struct fuse_file *ff = file->private_data;
1091         struct fuse_conn *fc = ff->fc;
1092         size_t nmax = write ? fc->max_write : fc->max_read;
1093         loff_t pos = *ppos;
1094         ssize_t res = 0;
1095         struct fuse_req *req;
1096
1097         req = fuse_get_req(fc);
1098         if (IS_ERR(req))
1099                 return PTR_ERR(req);
1100
1101         while (count) {
1102                 size_t nres;
1103                 fl_owner_t owner = current->files;
1104                 size_t nbytes = min(count, nmax);
1105                 int err = fuse_get_user_pages(req, buf, &nbytes, write);
1106                 if (err) {
1107                         res = err;
1108                         break;
1109                 }
1110
1111                 if (write)
1112                         nres = fuse_send_write(req, file, pos, nbytes, owner);
1113                 else
1114                         nres = fuse_send_read(req, file, pos, nbytes, owner);
1115
1116                 fuse_release_user_pages(req, !write);
1117                 if (req->out.h.error) {
1118                         if (!res)
1119                                 res = req->out.h.error;
1120                         break;
1121                 } else if (nres > nbytes) {
1122                         res = -EIO;
1123                         break;
1124                 }
1125                 count -= nres;
1126                 res += nres;
1127                 pos += nres;
1128                 buf += nres;
1129                 if (nres != nbytes)
1130                         break;
1131                 if (count) {
1132                         fuse_put_request(fc, req);
1133                         req = fuse_get_req(fc);
1134                         if (IS_ERR(req))
1135                                 break;
1136                 }
1137         }
1138         if (!IS_ERR(req))
1139                 fuse_put_request(fc, req);
1140         if (res > 0)
1141                 *ppos = pos;
1142
1143         return res;
1144 }
1145 EXPORT_SYMBOL_GPL(fuse_direct_io);
1146
1147 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1148                                      size_t count, loff_t *ppos)
1149 {
1150         ssize_t res;
1151         struct inode *inode = file->f_path.dentry->d_inode;
1152
1153         if (is_bad_inode(inode))
1154                 return -EIO;
1155
1156         res = fuse_direct_io(file, buf, count, ppos, 0);
1157
1158         fuse_invalidate_attr(inode);
1159
1160         return res;
1161 }
1162
1163 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1164                                  size_t count, loff_t *ppos)
1165 {
1166         struct inode *inode = file->f_path.dentry->d_inode;
1167         ssize_t res;
1168
1169         if (is_bad_inode(inode))
1170                 return -EIO;
1171
1172         /* Don't allow parallel writes to the same file */
1173         mutex_lock(&inode->i_mutex);
1174         res = generic_write_checks(file, ppos, &count, 0);
1175         if (!res) {
1176                 res = fuse_direct_io(file, buf, count, ppos, 1);
1177                 if (res > 0)
1178                         fuse_write_update_size(inode, *ppos);
1179         }
1180         mutex_unlock(&inode->i_mutex);
1181
1182         fuse_invalidate_attr(inode);
1183
1184         return res;
1185 }
1186
1187 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1188 {
1189         __free_page(req->pages[0]);
1190         fuse_file_put(req->ff, false);
1191 }
1192
1193 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1194 {
1195         struct inode *inode = req->inode;
1196         struct fuse_inode *fi = get_fuse_inode(inode);
1197         struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1198
1199         list_del(&req->writepages_entry);
1200         dec_bdi_stat(bdi, BDI_WRITEBACK);
1201         dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
1202         bdi_writeout_inc(bdi);
1203         wake_up(&fi->page_waitq);
1204 }
1205
1206 /* Called under fc->lock, may release and reacquire it */
1207 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
1208 __releases(fc->lock)
1209 __acquires(fc->lock)
1210 {
1211         struct fuse_inode *fi = get_fuse_inode(req->inode);
1212         loff_t size = i_size_read(req->inode);
1213         struct fuse_write_in *inarg = &req->misc.write.in;
1214
1215         if (!fc->connected)
1216                 goto out_free;
1217
1218         if (inarg->offset + PAGE_CACHE_SIZE <= size) {
1219                 inarg->size = PAGE_CACHE_SIZE;
1220         } else if (inarg->offset < size) {
1221                 inarg->size = size & (PAGE_CACHE_SIZE - 1);
1222         } else {
1223                 /* Got truncated off completely */
1224                 goto out_free;
1225         }
1226
1227         req->in.args[1].size = inarg->size;
1228         fi->writectr++;
1229         fuse_request_send_background_locked(fc, req);
1230         return;
1231
1232  out_free:
1233         fuse_writepage_finish(fc, req);
1234         spin_unlock(&fc->lock);
1235         fuse_writepage_free(fc, req);
1236         fuse_put_request(fc, req);
1237         spin_lock(&fc->lock);
1238 }
1239
1240 /*
1241  * If fi->writectr is positive (no truncate or fsync going on) send
1242  * all queued writepage requests.
1243  *
1244  * Called with fc->lock
1245  */
1246 void fuse_flush_writepages(struct inode *inode)
1247 __releases(fc->lock)
1248 __acquires(fc->lock)
1249 {
1250         struct fuse_conn *fc = get_fuse_conn(inode);
1251         struct fuse_inode *fi = get_fuse_inode(inode);
1252         struct fuse_req *req;
1253
1254         while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1255                 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1256                 list_del_init(&req->list);
1257                 fuse_send_writepage(fc, req);
1258         }
1259 }
1260
1261 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1262 {
1263         struct inode *inode = req->inode;
1264         struct fuse_inode *fi = get_fuse_inode(inode);
1265
1266         mapping_set_error(inode->i_mapping, req->out.h.error);
1267         spin_lock(&fc->lock);
1268         fi->writectr--;
1269         fuse_writepage_finish(fc, req);
1270         spin_unlock(&fc->lock);
1271         fuse_writepage_free(fc, req);
1272 }
1273
1274 static int fuse_writepage_locked(struct page *page)
1275 {
1276         struct address_space *mapping = page->mapping;
1277         struct inode *inode = mapping->host;
1278         struct fuse_conn *fc = get_fuse_conn(inode);
1279         struct fuse_inode *fi = get_fuse_inode(inode);
1280         struct fuse_req *req;
1281         struct fuse_file *ff;
1282         struct page *tmp_page;
1283
1284         set_page_writeback(page);
1285
1286         req = fuse_request_alloc_nofs();
1287         if (!req)
1288                 goto err;
1289
1290         tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1291         if (!tmp_page)
1292                 goto err_free;
1293
1294         spin_lock(&fc->lock);
1295         BUG_ON(list_empty(&fi->write_files));
1296         ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
1297         req->ff = fuse_file_get(ff);
1298         spin_unlock(&fc->lock);
1299
1300         fuse_write_fill(req, ff, page_offset(page), 0);
1301
1302         copy_highpage(tmp_page, page);
1303         req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1304         req->in.argpages = 1;
1305         req->num_pages = 1;
1306         req->pages[0] = tmp_page;
1307         req->page_offset = 0;
1308         req->end = fuse_writepage_end;
1309         req->inode = inode;
1310
1311         inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1312         inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1313         end_page_writeback(page);
1314
1315         spin_lock(&fc->lock);
1316         list_add(&req->writepages_entry, &fi->writepages);
1317         list_add_tail(&req->list, &fi->queued_writes);
1318         fuse_flush_writepages(inode);
1319         spin_unlock(&fc->lock);
1320
1321         return 0;
1322
1323 err_free:
1324         fuse_request_free(req);
1325 err:
1326         end_page_writeback(page);
1327         return -ENOMEM;
1328 }
1329
1330 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1331 {
1332         int err;
1333
1334         err = fuse_writepage_locked(page);
1335         unlock_page(page);
1336
1337         return err;
1338 }
1339
1340 static int fuse_launder_page(struct page *page)
1341 {
1342         int err = 0;
1343         if (clear_page_dirty_for_io(page)) {
1344                 struct inode *inode = page->mapping->host;
1345                 err = fuse_writepage_locked(page);
1346                 if (!err)
1347                         fuse_wait_on_page_writeback(inode, page->index);
1348         }
1349         return err;
1350 }
1351
1352 /*
1353  * Write back dirty pages now, because there may not be any suitable
1354  * open files later
1355  */
1356 static void fuse_vma_close(struct vm_area_struct *vma)
1357 {
1358         filemap_write_and_wait(vma->vm_file->f_mapping);
1359 }
1360
1361 /*
1362  * Wait for writeback against this page to complete before allowing it
1363  * to be marked dirty again, and hence written back again, possibly
1364  * before the previous writepage completed.
1365  *
1366  * Block here, instead of in ->writepage(), so that the userspace fs
1367  * can only block processes actually operating on the filesystem.
1368  *
1369  * Otherwise unprivileged userspace fs would be able to block
1370  * unrelated:
1371  *
1372  * - page migration
1373  * - sync(2)
1374  * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
1375  */
1376 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1377 {
1378         struct page *page = vmf->page;
1379         /*
1380          * Don't use page->mapping as it may become NULL from a
1381          * concurrent truncate.
1382          */
1383         struct inode *inode = vma->vm_file->f_mapping->host;
1384
1385         fuse_wait_on_page_writeback(inode, page->index);
1386         return 0;
1387 }
1388
1389 static const struct vm_operations_struct fuse_file_vm_ops = {
1390         .close          = fuse_vma_close,
1391         .fault          = filemap_fault,
1392         .page_mkwrite   = fuse_page_mkwrite,
1393 };
1394
1395 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
1396 {
1397         if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
1398                 struct inode *inode = file->f_dentry->d_inode;
1399                 struct fuse_conn *fc = get_fuse_conn(inode);
1400                 struct fuse_inode *fi = get_fuse_inode(inode);
1401                 struct fuse_file *ff = file->private_data;
1402                 /*
1403                  * file may be written through mmap, so chain it onto the
1404                  * inodes's write_file list
1405                  */
1406                 spin_lock(&fc->lock);
1407                 if (list_empty(&ff->write_entry))
1408                         list_add(&ff->write_entry, &fi->write_files);
1409                 spin_unlock(&fc->lock);
1410         }
1411         file_accessed(file);
1412         vma->vm_ops = &fuse_file_vm_ops;
1413         return 0;
1414 }
1415
1416 static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
1417 {
1418         /* Can't provide the coherency needed for MAP_SHARED */
1419         if (vma->vm_flags & VM_MAYSHARE)
1420                 return -ENODEV;
1421
1422         invalidate_inode_pages2(file->f_mapping);
1423
1424         return generic_file_mmap(file, vma);
1425 }
1426
1427 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
1428                                   struct file_lock *fl)
1429 {
1430         switch (ffl->type) {
1431         case F_UNLCK:
1432                 break;
1433
1434         case F_RDLCK:
1435         case F_WRLCK:
1436                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
1437                     ffl->end < ffl->start)
1438                         return -EIO;
1439
1440                 fl->fl_start = ffl->start;
1441                 fl->fl_end = ffl->end;
1442                 fl->fl_pid = ffl->pid;
1443                 break;
1444
1445         default:
1446                 return -EIO;
1447         }
1448         fl->fl_type = ffl->type;
1449         return 0;
1450 }
1451
1452 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1453                          const struct file_lock *fl, int opcode, pid_t pid,
1454                          int flock)
1455 {
1456         struct inode *inode = file->f_path.dentry->d_inode;
1457         struct fuse_conn *fc = get_fuse_conn(inode);
1458         struct fuse_file *ff = file->private_data;
1459         struct fuse_lk_in *arg = &req->misc.lk_in;
1460
1461         arg->fh = ff->fh;
1462         arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1463         arg->lk.start = fl->fl_start;
1464         arg->lk.end = fl->fl_end;
1465         arg->lk.type = fl->fl_type;
1466         arg->lk.pid = pid;
1467         if (flock)
1468                 arg->lk_flags |= FUSE_LK_FLOCK;
1469         req->in.h.opcode = opcode;
1470         req->in.h.nodeid = get_node_id(inode);
1471         req->in.numargs = 1;
1472         req->in.args[0].size = sizeof(*arg);
1473         req->in.args[0].value = arg;
1474 }
1475
1476 static int fuse_getlk(struct file *file, struct file_lock *fl)
1477 {
1478         struct inode *inode = file->f_path.dentry->d_inode;
1479         struct fuse_conn *fc = get_fuse_conn(inode);
1480         struct fuse_req *req;
1481         struct fuse_lk_out outarg;
1482         int err;
1483
1484         req = fuse_get_req(fc);
1485         if (IS_ERR(req))
1486                 return PTR_ERR(req);
1487
1488         fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1489         req->out.numargs = 1;
1490         req->out.args[0].size = sizeof(outarg);
1491         req->out.args[0].value = &outarg;
1492         fuse_request_send(fc, req);
1493         err = req->out.h.error;
1494         fuse_put_request(fc, req);
1495         if (!err)
1496                 err = convert_fuse_file_lock(&outarg.lk, fl);
1497
1498         return err;
1499 }
1500
1501 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1502 {
1503         struct inode *inode = file->f_path.dentry->d_inode;
1504         struct fuse_conn *fc = get_fuse_conn(inode);
1505         struct fuse_req *req;
1506         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
1507         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
1508         int err;
1509
1510         if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
1511                 /* NLM needs asynchronous locks, which we don't support yet */
1512                 return -ENOLCK;
1513         }
1514
1515         /* Unlock on close is handled by the flush method */
1516         if (fl->fl_flags & FL_CLOSE)
1517                 return 0;
1518
1519         req = fuse_get_req(fc);
1520         if (IS_ERR(req))
1521                 return PTR_ERR(req);
1522
1523         fuse_lk_fill(req, file, fl, opcode, pid, flock);
1524         fuse_request_send(fc, req);
1525         err = req->out.h.error;
1526         /* locking is restartable */
1527         if (err == -EINTR)
1528                 err = -ERESTARTSYS;
1529         fuse_put_request(fc, req);
1530         return err;
1531 }
1532
1533 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
1534 {
1535         struct inode *inode = file->f_path.dentry->d_inode;
1536         struct fuse_conn *fc = get_fuse_conn(inode);
1537         int err;
1538
1539         if (cmd == F_CANCELLK) {
1540                 err = 0;
1541         } else if (cmd == F_GETLK) {
1542                 if (fc->no_lock) {
1543                         posix_test_lock(file, fl);
1544                         err = 0;
1545                 } else
1546                         err = fuse_getlk(file, fl);
1547         } else {
1548                 if (fc->no_lock)
1549                         err = posix_lock_file(file, fl, NULL);
1550                 else
1551                         err = fuse_setlk(file, fl, 0);
1552         }
1553         return err;
1554 }
1555
1556 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
1557 {
1558         struct inode *inode = file->f_path.dentry->d_inode;
1559         struct fuse_conn *fc = get_fuse_conn(inode);
1560         int err;
1561
1562         if (fc->no_lock) {
1563                 err = flock_lock_file_wait(file, fl);
1564         } else {
1565                 /* emulate flock with POSIX locks */
1566                 fl->fl_owner = (fl_owner_t) file;
1567                 err = fuse_setlk(file, fl, 1);
1568         }
1569
1570         return err;
1571 }
1572
1573 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
1574 {
1575         struct inode *inode = mapping->host;
1576         struct fuse_conn *fc = get_fuse_conn(inode);
1577         struct fuse_req *req;
1578         struct fuse_bmap_in inarg;
1579         struct fuse_bmap_out outarg;
1580         int err;
1581
1582         if (!inode->i_sb->s_bdev || fc->no_bmap)
1583                 return 0;
1584
1585         req = fuse_get_req(fc);
1586         if (IS_ERR(req))
1587                 return 0;
1588
1589         memset(&inarg, 0, sizeof(inarg));
1590         inarg.block = block;
1591         inarg.blocksize = inode->i_sb->s_blocksize;
1592         req->in.h.opcode = FUSE_BMAP;
1593         req->in.h.nodeid = get_node_id(inode);
1594         req->in.numargs = 1;
1595         req->in.args[0].size = sizeof(inarg);
1596         req->in.args[0].value = &inarg;
1597         req->out.numargs = 1;
1598         req->out.args[0].size = sizeof(outarg);
1599         req->out.args[0].value = &outarg;
1600         fuse_request_send(fc, req);
1601         err = req->out.h.error;
1602         fuse_put_request(fc, req);
1603         if (err == -ENOSYS)
1604                 fc->no_bmap = 1;
1605
1606         return err ? 0 : outarg.block;
1607 }
1608
1609 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
1610 {
1611         loff_t retval;
1612         struct inode *inode = file->f_path.dentry->d_inode;
1613
1614         mutex_lock(&inode->i_mutex);
1615         if (origin != SEEK_CUR || origin != SEEK_SET) {
1616                 retval = fuse_update_attributes(inode, NULL, file, NULL);
1617                 if (retval)
1618                         goto exit;
1619         }
1620
1621         switch (origin) {
1622         case SEEK_END:
1623                 offset += i_size_read(inode);
1624                 break;
1625         case SEEK_CUR:
1626                 offset += file->f_pos;
1627                 break;
1628         case SEEK_DATA:
1629                 if (offset >= i_size_read(inode)) {
1630                         retval = -ENXIO;
1631                         goto exit;
1632                 }
1633                 break;
1634         case SEEK_HOLE:
1635                 if (offset >= i_size_read(inode)) {
1636                         retval = -ENXIO;
1637                         goto exit;
1638                 }
1639                 offset = i_size_read(inode);
1640                 break;
1641         }
1642         retval = -EINVAL;
1643         if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
1644                 if (offset != file->f_pos) {
1645                         file->f_pos = offset;
1646                         file->f_version = 0;
1647                 }
1648                 retval = offset;
1649         }
1650 exit:
1651         mutex_unlock(&inode->i_mutex);
1652         return retval;
1653 }
1654
1655 static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
1656                         unsigned int nr_segs, size_t bytes, bool to_user)
1657 {
1658         struct iov_iter ii;
1659         int page_idx = 0;
1660
1661         if (!bytes)
1662                 return 0;
1663
1664         iov_iter_init(&ii, iov, nr_segs, bytes, 0);
1665
1666         while (iov_iter_count(&ii)) {
1667                 struct page *page = pages[page_idx++];
1668                 size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
1669                 void *kaddr;
1670
1671                 kaddr = kmap(page);
1672
1673                 while (todo) {
1674                         char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
1675                         size_t iov_len = ii.iov->iov_len - ii.iov_offset;
1676                         size_t copy = min(todo, iov_len);
1677                         size_t left;
1678
1679                         if (!to_user)
1680                                 left = copy_from_user(kaddr, uaddr, copy);
1681                         else
1682                                 left = copy_to_user(uaddr, kaddr, copy);
1683
1684                         if (unlikely(left))
1685                                 return -EFAULT;
1686
1687                         iov_iter_advance(&ii, copy);
1688                         todo -= copy;
1689                         kaddr += copy;
1690                 }
1691
1692                 kunmap(page);
1693         }
1694
1695         return 0;
1696 }
1697
1698 /*
1699  * CUSE servers compiled on 32bit broke on 64bit kernels because the
1700  * ABI was defined to be 'struct iovec' which is different on 32bit
1701  * and 64bit.  Fortunately we can determine which structure the server
1702  * used from the size of the reply.
1703  */
1704 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
1705                                      size_t transferred, unsigned count,
1706                                      bool is_compat)
1707 {
1708 #ifdef CONFIG_COMPAT
1709         if (count * sizeof(struct compat_iovec) == transferred) {
1710                 struct compat_iovec *ciov = src;
1711                 unsigned i;
1712
1713                 /*
1714                  * With this interface a 32bit server cannot support
1715                  * non-compat (i.e. ones coming from 64bit apps) ioctl
1716                  * requests
1717                  */
1718                 if (!is_compat)
1719                         return -EINVAL;
1720
1721                 for (i = 0; i < count; i++) {
1722                         dst[i].iov_base = compat_ptr(ciov[i].iov_base);
1723                         dst[i].iov_len = ciov[i].iov_len;
1724                 }
1725                 return 0;
1726         }
1727 #endif
1728
1729         if (count * sizeof(struct iovec) != transferred)
1730                 return -EIO;
1731
1732         memcpy(dst, src, transferred);
1733         return 0;
1734 }
1735
1736 /* Make sure iov_length() won't overflow */
1737 static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
1738 {
1739         size_t n;
1740         u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
1741
1742         for (n = 0; n < count; n++) {
1743                 if (iov->iov_len > (size_t) max)
1744                         return -ENOMEM;
1745                 max -= iov->iov_len;
1746         }
1747         return 0;
1748 }
1749
1750 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
1751                                  void *src, size_t transferred, unsigned count,
1752                                  bool is_compat)
1753 {
1754         unsigned i;
1755         struct fuse_ioctl_iovec *fiov = src;
1756
1757         if (fc->minor < 16) {
1758                 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
1759                                                  count, is_compat);
1760         }
1761
1762         if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
1763                 return -EIO;
1764
1765         for (i = 0; i < count; i++) {
1766                 /* Did the server supply an inappropriate value? */
1767                 if (fiov[i].base != (unsigned long) fiov[i].base ||
1768                     fiov[i].len != (unsigned long) fiov[i].len)
1769                         return -EIO;
1770
1771                 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
1772                 dst[i].iov_len = (size_t) fiov[i].len;
1773
1774 #ifdef CONFIG_COMPAT
1775                 if (is_compat &&
1776                     (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
1777                      (compat_size_t) dst[i].iov_len != fiov[i].len))
1778                         return -EIO;
1779 #endif
1780         }
1781
1782         return 0;
1783 }
1784
1785
1786 /*
1787  * For ioctls, there is no generic way to determine how much memory
1788  * needs to be read and/or written.  Furthermore, ioctls are allowed
1789  * to dereference the passed pointer, so the parameter requires deep
1790  * copying but FUSE has no idea whatsoever about what to copy in or
1791  * out.
1792  *
1793  * This is solved by allowing FUSE server to retry ioctl with
1794  * necessary in/out iovecs.  Let's assume the ioctl implementation
1795  * needs to read in the following structure.
1796  *
1797  * struct a {
1798  *      char    *buf;
1799  *      size_t  buflen;
1800  * }
1801  *
1802  * On the first callout to FUSE server, inarg->in_size and
1803  * inarg->out_size will be NULL; then, the server completes the ioctl
1804  * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
1805  * the actual iov array to
1806  *
1807  * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a) } }
1808  *
1809  * which tells FUSE to copy in the requested area and retry the ioctl.
1810  * On the second round, the server has access to the structure and
1811  * from that it can tell what to look for next, so on the invocation,
1812  * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
1813  *
1814  * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a)     },
1815  *   { .iov_base = a.buf,       .iov_len = a.buflen             } }
1816  *
1817  * FUSE will copy both struct a and the pointed buffer from the
1818  * process doing the ioctl and retry ioctl with both struct a and the
1819  * buffer.
1820  *
1821  * This time, FUSE server has everything it needs and completes ioctl
1822  * without FUSE_IOCTL_RETRY which finishes the ioctl call.
1823  *
1824  * Copying data out works the same way.
1825  *
1826  * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
1827  * automatically initializes in and out iovs by decoding @cmd with
1828  * _IOC_* macros and the server is not allowed to request RETRY.  This
1829  * limits ioctl data transfers to well-formed ioctls and is the forced
1830  * behavior for all FUSE servers.
1831  */
1832 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1833                    unsigned int flags)
1834 {
1835         struct fuse_file *ff = file->private_data;
1836         struct fuse_conn *fc = ff->fc;
1837         struct fuse_ioctl_in inarg = {
1838                 .fh = ff->fh,
1839                 .cmd = cmd,
1840                 .arg = arg,
1841                 .flags = flags
1842         };
1843         struct fuse_ioctl_out outarg;
1844         struct fuse_req *req = NULL;
1845         struct page **pages = NULL;
1846         struct iovec *iov_page = NULL;
1847         struct iovec *in_iov = NULL, *out_iov = NULL;
1848         unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
1849         size_t in_size, out_size, transferred;
1850         int err;
1851
1852 #if BITS_PER_LONG == 32
1853         inarg.flags |= FUSE_IOCTL_32BIT;
1854 #else
1855         if (flags & FUSE_IOCTL_COMPAT)
1856                 inarg.flags |= FUSE_IOCTL_32BIT;
1857 #endif
1858
1859         /* assume all the iovs returned by client always fits in a page */
1860         BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
1861
1862         err = -ENOMEM;
1863         pages = kzalloc(sizeof(pages[0]) * FUSE_MAX_PAGES_PER_REQ, GFP_KERNEL);
1864         iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
1865         if (!pages || !iov_page)
1866                 goto out;
1867
1868         /*
1869          * If restricted, initialize IO parameters as encoded in @cmd.
1870          * RETRY from server is not allowed.
1871          */
1872         if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
1873                 struct iovec *iov = iov_page;
1874
1875                 iov->iov_base = (void __user *)arg;
1876                 iov->iov_len = _IOC_SIZE(cmd);
1877
1878                 if (_IOC_DIR(cmd) & _IOC_WRITE) {
1879                         in_iov = iov;
1880                         in_iovs = 1;
1881                 }
1882
1883                 if (_IOC_DIR(cmd) & _IOC_READ) {
1884                         out_iov = iov;
1885                         out_iovs = 1;
1886                 }
1887         }
1888
1889  retry:
1890         inarg.in_size = in_size = iov_length(in_iov, in_iovs);
1891         inarg.out_size = out_size = iov_length(out_iov, out_iovs);
1892
1893         /*
1894          * Out data can be used either for actual out data or iovs,
1895          * make sure there always is at least one page.
1896          */
1897         out_size = max_t(size_t, out_size, PAGE_SIZE);
1898         max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
1899
1900         /* make sure there are enough buffer pages and init request with them */
1901         err = -ENOMEM;
1902         if (max_pages > FUSE_MAX_PAGES_PER_REQ)
1903                 goto out;
1904         while (num_pages < max_pages) {
1905                 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
1906                 if (!pages[num_pages])
1907                         goto out;
1908                 num_pages++;
1909         }
1910
1911         req = fuse_get_req(fc);
1912         if (IS_ERR(req)) {
1913                 err = PTR_ERR(req);
1914                 req = NULL;
1915                 goto out;
1916         }
1917         memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
1918         req->num_pages = num_pages;
1919
1920         /* okay, let's send it to the client */
1921         req->in.h.opcode = FUSE_IOCTL;
1922         req->in.h.nodeid = ff->nodeid;
1923         req->in.numargs = 1;
1924         req->in.args[0].size = sizeof(inarg);
1925         req->in.args[0].value = &inarg;
1926         if (in_size) {
1927                 req->in.numargs++;
1928                 req->in.args[1].size = in_size;
1929                 req->in.argpages = 1;
1930
1931                 err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
1932                                            false);
1933                 if (err)
1934                         goto out;
1935         }
1936
1937         req->out.numargs = 2;
1938         req->out.args[0].size = sizeof(outarg);
1939         req->out.args[0].value = &outarg;
1940         req->out.args[1].size = out_size;
1941         req->out.argpages = 1;
1942         req->out.argvar = 1;
1943
1944         fuse_request_send(fc, req);
1945         err = req->out.h.error;
1946         transferred = req->out.args[1].size;
1947         fuse_put_request(fc, req);
1948         req = NULL;
1949         if (err)
1950                 goto out;
1951
1952         /* did it ask for retry? */
1953         if (outarg.flags & FUSE_IOCTL_RETRY) {
1954                 void *vaddr;
1955
1956                 /* no retry if in restricted mode */
1957                 err = -EIO;
1958                 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
1959                         goto out;
1960
1961                 in_iovs = outarg.in_iovs;
1962                 out_iovs = outarg.out_iovs;
1963
1964                 /*
1965                  * Make sure things are in boundary, separate checks
1966                  * are to protect against overflow.
1967                  */
1968                 err = -ENOMEM;
1969                 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
1970                     out_iovs > FUSE_IOCTL_MAX_IOV ||
1971                     in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
1972                         goto out;
1973
1974                 vaddr = kmap_atomic(pages[0], KM_USER0);
1975                 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
1976                                             transferred, in_iovs + out_iovs,
1977                                             (flags & FUSE_IOCTL_COMPAT) != 0);
1978                 kunmap_atomic(vaddr, KM_USER0);
1979                 if (err)
1980                         goto out;
1981
1982                 in_iov = iov_page;
1983                 out_iov = in_iov + in_iovs;
1984
1985                 err = fuse_verify_ioctl_iov(in_iov, in_iovs);
1986                 if (err)
1987                         goto out;
1988
1989                 err = fuse_verify_ioctl_iov(out_iov, out_iovs);
1990                 if (err)
1991                         goto out;
1992
1993                 goto retry;
1994         }
1995
1996         err = -EIO;
1997         if (transferred > inarg.out_size)
1998                 goto out;
1999
2000         err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
2001  out:
2002         if (req)
2003                 fuse_put_request(fc, req);
2004         free_page((unsigned long) iov_page);
2005         while (num_pages)
2006                 __free_page(pages[--num_pages]);
2007         kfree(pages);
2008
2009         return err ? err : outarg.result;
2010 }
2011 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2012
2013 static long fuse_file_ioctl_common(struct file *file, unsigned int cmd,
2014                                    unsigned long arg, unsigned int flags)
2015 {
2016         struct inode *inode = file->f_dentry->d_inode;
2017         struct fuse_conn *fc = get_fuse_conn(inode);
2018
2019         if (!fuse_allow_task(fc, current))
2020                 return -EACCES;
2021
2022         if (is_bad_inode(inode))
2023                 return -EIO;
2024
2025         return fuse_do_ioctl(file, cmd, arg, flags);
2026 }
2027
2028 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2029                             unsigned long arg)
2030 {
2031         return fuse_file_ioctl_common(file, cmd, arg, 0);
2032 }
2033
2034 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2035                                    unsigned long arg)
2036 {
2037         return fuse_file_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2038 }
2039
2040 /*
2041  * All files which have been polled are linked to RB tree
2042  * fuse_conn->polled_files which is indexed by kh.  Walk the tree and
2043  * find the matching one.
2044  */
2045 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2046                                               struct rb_node **parent_out)
2047 {
2048         struct rb_node **link = &fc->polled_files.rb_node;
2049         struct rb_node *last = NULL;
2050
2051         while (*link) {
2052                 struct fuse_file *ff;
2053
2054                 last = *link;
2055                 ff = rb_entry(last, struct fuse_file, polled_node);
2056
2057                 if (kh < ff->kh)
2058                         link = &last->rb_left;
2059                 else if (kh > ff->kh)
2060                         link = &last->rb_right;
2061                 else
2062                         return link;
2063         }
2064
2065         if (parent_out)
2066                 *parent_out = last;
2067         return link;
2068 }
2069
2070 /*
2071  * The file is about to be polled.  Make sure it's on the polled_files
2072  * RB tree.  Note that files once added to the polled_files tree are
2073  * not removed before the file is released.  This is because a file
2074  * polled once is likely to be polled again.
2075  */
2076 static void fuse_register_polled_file(struct fuse_conn *fc,
2077                                       struct fuse_file *ff)
2078 {
2079         spin_lock(&fc->lock);
2080         if (RB_EMPTY_NODE(&ff->polled_node)) {
2081                 struct rb_node **link, *parent;
2082
2083                 link = fuse_find_polled_node(fc, ff->kh, &parent);
2084                 BUG_ON(*link);
2085                 rb_link_node(&ff->polled_node, parent, link);
2086                 rb_insert_color(&ff->polled_node, &fc->polled_files);
2087         }
2088         spin_unlock(&fc->lock);
2089 }
2090
2091 unsigned fuse_file_poll(struct file *file, poll_table *wait)
2092 {
2093         struct fuse_file *ff = file->private_data;
2094         struct fuse_conn *fc = ff->fc;
2095         struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2096         struct fuse_poll_out outarg;
2097         struct fuse_req *req;
2098         int err;
2099
2100         if (fc->no_poll)
2101                 return DEFAULT_POLLMASK;
2102
2103         poll_wait(file, &ff->poll_wait, wait);
2104
2105         /*
2106          * Ask for notification iff there's someone waiting for it.
2107          * The client may ignore the flag and always notify.
2108          */
2109         if (waitqueue_active(&ff->poll_wait)) {
2110                 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2111                 fuse_register_polled_file(fc, ff);
2112         }
2113
2114         req = fuse_get_req(fc);
2115         if (IS_ERR(req))
2116                 return POLLERR;
2117
2118         req->in.h.opcode = FUSE_POLL;
2119         req->in.h.nodeid = ff->nodeid;
2120         req->in.numargs = 1;
2121         req->in.args[0].size = sizeof(inarg);
2122         req->in.args[0].value = &inarg;
2123         req->out.numargs = 1;
2124         req->out.args[0].size = sizeof(outarg);
2125         req->out.args[0].value = &outarg;
2126         fuse_request_send(fc, req);
2127         err = req->out.h.error;
2128         fuse_put_request(fc, req);
2129
2130         if (!err)
2131                 return outarg.revents;
2132         if (err == -ENOSYS) {
2133                 fc->no_poll = 1;
2134                 return DEFAULT_POLLMASK;
2135         }
2136         return POLLERR;
2137 }
2138 EXPORT_SYMBOL_GPL(fuse_file_poll);
2139
2140 /*
2141  * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2142  * wakes up the poll waiters.
2143  */
2144 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2145                             struct fuse_notify_poll_wakeup_out *outarg)
2146 {
2147         u64 kh = outarg->kh;
2148         struct rb_node **link;
2149
2150         spin_lock(&fc->lock);
2151
2152         link = fuse_find_polled_node(fc, kh, NULL);
2153         if (*link) {
2154                 struct fuse_file *ff;
2155
2156                 ff = rb_entry(*link, struct fuse_file, polled_node);
2157                 wake_up_interruptible_sync(&ff->poll_wait);
2158         }
2159
2160         spin_unlock(&fc->lock);
2161         return 0;
2162 }
2163
2164 static const struct file_operations fuse_file_operations = {
2165         .llseek         = fuse_file_llseek,
2166         .read           = do_sync_read,
2167         .aio_read       = fuse_file_aio_read,
2168         .write          = do_sync_write,
2169         .aio_write      = fuse_file_aio_write,
2170         .mmap           = fuse_file_mmap,
2171         .open           = fuse_open,
2172         .flush          = fuse_flush,
2173         .release        = fuse_release,
2174         .fsync          = fuse_fsync,
2175         .lock           = fuse_file_lock,
2176         .flock          = fuse_file_flock,
2177         .splice_read    = generic_file_splice_read,
2178         .unlocked_ioctl = fuse_file_ioctl,
2179         .compat_ioctl   = fuse_file_compat_ioctl,
2180         .poll           = fuse_file_poll,
2181 };
2182
2183 static const struct file_operations fuse_direct_io_file_operations = {
2184         .llseek         = fuse_file_llseek,
2185         .read           = fuse_direct_read,
2186         .write          = fuse_direct_write,
2187         .mmap           = fuse_direct_mmap,
2188         .open           = fuse_open,
2189         .flush          = fuse_flush,
2190         .release        = fuse_release,
2191         .fsync          = fuse_fsync,
2192         .lock           = fuse_file_lock,
2193         .flock          = fuse_file_flock,
2194         .unlocked_ioctl = fuse_file_ioctl,
2195         .compat_ioctl   = fuse_file_compat_ioctl,
2196         .poll           = fuse_file_poll,
2197         /* no splice_read */
2198 };
2199
2200 static const struct address_space_operations fuse_file_aops  = {
2201         .readpage       = fuse_readpage,
2202         .writepage      = fuse_writepage,
2203         .launder_page   = fuse_launder_page,
2204         .write_begin    = fuse_write_begin,
2205         .write_end      = fuse_write_end,
2206         .readpages      = fuse_readpages,
2207         .set_page_dirty = __set_page_dirty_nobuffers,
2208         .bmap           = fuse_bmap,
2209 };
2210
2211 void fuse_init_file_inode(struct inode *inode)
2212 {
2213         inode->i_fop = &fuse_file_operations;
2214         inode->i_data.a_ops = &fuse_file_aops;
2215 }