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