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