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 #include <linux/falloc.h>
  19 #include <linux/uio.h>
  20 #include <linux/fs.h>
  21
  22 static const struct file_operations fuse_direct_io_file_operations;
  23
  24 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
  25                           int opcode, struct fuse_open_out *outargp)
  26 {
  27         struct fuse_open_in inarg;
  28         FUSE_ARGS(args);
  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         args.in.h.opcode = opcode;
  35         args.in.h.nodeid = nodeid;
  36         args.in.numargs = 1;
  37         args.in.args[0].size = sizeof(inarg);
  38         args.in.args[0].value = &inarg;
  39         args.out.numargs = 1;
  40         args.out.args[0].size = sizeof(*outargp);
  41         args.out.args[0].value = outargp;
  42
  43         return fuse_simple_request(fc, &args);
  44 }
  45
  46 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
  47 {
  48         struct fuse_file *ff;
  49
  50         ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL);
  51         if (unlikely(!ff))
  52                 return NULL;
  53
  54         ff->fc = fc;
  55         ff->reserved_req = fuse_request_alloc(0);
  56         if (unlikely(!ff->reserved_req)) {
  57                 kfree(ff);
  58                 return NULL;
  59         }
  60
  61         INIT_LIST_HEAD(&ff->write_entry);
  62         atomic_set(&ff->count, 0);
  63         RB_CLEAR_NODE(&ff->polled_node);
  64         init_waitqueue_head(&ff->poll_wait);
  65
  66         spin_lock(&fc->lock);
  67         ff->kh = ++fc->khctr;
  68         spin_unlock(&fc->lock);
  69
  70         return ff;
  71 }
  72
  73 void fuse_file_free(struct fuse_file *ff)
  74 {
  75         fuse_request_free(ff->reserved_req);
  76         kfree(ff);
  77 }
  78
  79 struct fuse_file *fuse_file_get(struct fuse_file *ff)
  80 {
  81         atomic_inc(&ff->count);
  82         return ff;
  83 }
  84
  85 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
  86 {
  87         iput(req->misc.release.inode);
  88 }
  89
  90 static void fuse_file_put(struct fuse_file *ff, bool sync)
  91 {
  92         if (atomic_dec_and_test(&ff->count)) {
  93                 struct fuse_req *req = ff->reserved_req;
  94
  95                 if (ff->fc->no_open) {
  96                         /*
  97                          * Drop the release request when client does not
  98                          * implement 'open'
  99                          */
 100                         __clear_bit(FR_BACKGROUND, &req->flags);
 101                         iput(req->misc.release.inode);
 102                         fuse_put_request(ff->fc, req);
 103                 } else if (sync) {
 104                         __set_bit(FR_FORCE, &req->flags);
 105                         __clear_bit(FR_BACKGROUND, &req->flags);
 106                         fuse_request_send(ff->fc, req);
 107                         iput(req->misc.release.inode);
 108                         fuse_put_request(ff->fc, req);
 109                 } else {
 110                         req->end = fuse_release_end;
 111                         __set_bit(FR_BACKGROUND, &req->flags);
 112                         fuse_request_send_background(ff->fc, req);
 113                 }
 114                 kfree(ff);
 115         }
 116 }
 117
 118 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 119                  bool isdir)
 120 {
 121         struct fuse_file *ff;
 122         int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
 123
 124         ff = fuse_file_alloc(fc);
 125         if (!ff)
 126                 return -ENOMEM;
 127
 128         ff->fh = 0;
 129         ff->open_flags = FOPEN_KEEP_CACHE; /* Default for no-open */
 130         if (!fc->no_open || isdir) {
 131                 struct fuse_open_out outarg;
 132                 int err;
 133
 134                 err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
 135                 if (!err) {
 136                         ff->fh = outarg.fh;
 137                         ff->open_flags = outarg.open_flags;
 138
 139                 } else if (err != -ENOSYS || isdir) {
 140                         fuse_file_free(ff);
 141                         return err;
 142                 } else {
 143                         fc->no_open = 1;
 144                 }
 145         }
 146
 147         if (isdir)
 148                 ff->open_flags &= ~FOPEN_DIRECT_IO;
 149
 150         ff->nodeid = nodeid;
 151         file->private_data = fuse_file_get(ff);
 152
 153         return 0;
 154 }
 155 EXPORT_SYMBOL_GPL(fuse_do_open);
 156
 157 static void fuse_link_write_file(struct file *file)
 158 {
 159         struct inode *inode = file_inode(file);
 160         struct fuse_conn *fc = get_fuse_conn(inode);
 161         struct fuse_inode *fi = get_fuse_inode(inode);
 162         struct fuse_file *ff = file->private_data;
 163         /*
 164          * file may be written through mmap, so chain it onto the
 165          * inodes's write_file list
 166          */
 167         spin_lock(&fc->lock);
 168         if (list_empty(&ff->write_entry))
 169                 list_add(&ff->write_entry, &fi->write_files);
 170         spin_unlock(&fc->lock);
 171 }
 172
 173 void fuse_finish_open(struct inode *inode, struct file *file)
 174 {
 175         struct fuse_file *ff = file->private_data;
 176         struct fuse_conn *fc = get_fuse_conn(inode);
 177
 178         if (ff->open_flags & FOPEN_DIRECT_IO)
 179                 file->f_op = &fuse_direct_io_file_operations;
 180         if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 181                 invalidate_inode_pages2(inode->i_mapping);
 182         if (ff->open_flags & FOPEN_STREAM)
 183                 stream_open(inode, file);
 184         else if (ff->open_flags & FOPEN_NONSEEKABLE)
 185                 nonseekable_open(inode, file);
 186         if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
 187                 struct fuse_inode *fi = get_fuse_inode(inode);
 188
 189                 spin_lock(&fc->lock);
 190                 fi->attr_version = ++fc->attr_version;
 191                 i_size_write(inode, 0);
 192                 spin_unlock(&fc->lock);
 193                 fuse_invalidate_attr(inode);
 194                 if (fc->writeback_cache)
 195                         file_update_time(file);
 196         }
 197         if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
 198                 fuse_link_write_file(file);
 199 }
 200
 201 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 202 {
 203         struct fuse_conn *fc = get_fuse_conn(inode);
 204         int err;
 205         bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
 206                           fc->atomic_o_trunc &&
 207                           fc->writeback_cache;
 208
 209         if (fuse_is_bad(inode))
 210                 return -EIO;
 211
 212         err = generic_file_open(inode, file);
 213         if (err)
 214                 return err;
 215
 216         if (is_wb_truncate) {
 217                 inode_lock(inode);
 218                 fuse_set_nowrite(inode);
 219         }
 220
 221         err = fuse_do_open(fc, get_node_id(inode), file, isdir);
 222
 223         if (!err)
 224                 fuse_finish_open(inode, file);
 225
 226         if (is_wb_truncate) {
 227                 fuse_release_nowrite(inode);
 228                 inode_unlock(inode);
 229         }
 230
 231         return err;
 232 }
 233
 234 static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
 235 {
 236         struct fuse_conn *fc = ff->fc;
 237         struct fuse_req *req = ff->reserved_req;
 238         struct fuse_release_in *inarg = &req->misc.release.in;
 239
 240         spin_lock(&fc->lock);
 241         list_del(&ff->write_entry);
 242         if (!RB_EMPTY_NODE(&ff->polled_node))
 243                 rb_erase(&ff->polled_node, &fc->polled_files);
 244         spin_unlock(&fc->lock);
 245
 246         wake_up_interruptible_all(&ff->poll_wait);
 247
 248         inarg->fh = ff->fh;
 249         inarg->flags = flags;
 250         req->in.h.opcode = opcode;
 251         req->in.h.nodeid = ff->nodeid;
 252         req->in.numargs = 1;
 253         req->in.args[0].size = sizeof(struct fuse_release_in);
 254         req->in.args[0].value = inarg;
 255 }
 256
 257 void fuse_release_common(struct file *file, int opcode)
 258 {
 259         struct fuse_file *ff;
 260         struct fuse_req *req;
 261
 262         ff = file->private_data;
 263         if (unlikely(!ff))
 264                 return;
 265
 266         req = ff->reserved_req;
 267         fuse_prepare_release(ff, file->f_flags, opcode);
 268
 269         if (ff->flock) {
 270                 struct fuse_release_in *inarg = &req->misc.release.in;
 271                 inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
 272                 inarg->lock_owner = fuse_lock_owner_id(ff->fc,
 273                                                        (fl_owner_t) file);
 274         }
 275         /* Hold inode until release is finished */
 276         req->misc.release.inode = igrab(file_inode(file));
 277
 278         /*
 279          * Normally this will send the RELEASE request, however if
 280          * some asynchronous READ or WRITE requests are outstanding,
 281          * the sending will be delayed.
 282          *
 283          * Make the release synchronous if this is a fuseblk mount,
 284          * synchronous RELEASE is allowed (and desirable) in this case
 285          * because the server can be trusted not to screw up.
 286          */
 287         fuse_file_put(ff, ff->fc->destroy_req != NULL);
 288 }
 289
 290 static int fuse_open(struct inode *inode, struct file *file)
 291 {
 292         return fuse_open_common(inode, file, false);
 293 }
 294
 295 static int fuse_release(struct inode *inode, struct file *file)
 296 {
 297         struct fuse_conn *fc = get_fuse_conn(inode);
 298
 299         /* see fuse_vma_close() for !writeback_cache case */
 300         if (fc->writeback_cache)
 301                 write_inode_now(inode, 1);
 302
 303         fuse_release_common(file, FUSE_RELEASE);
 304
 305         /* return value is ignored by VFS */
 306         return 0;
 307 }
 308
 309 void fuse_sync_release(struct fuse_file *ff, int flags)
 310 {
 311         WARN_ON(atomic_read(&ff->count) > 1);
 312         fuse_prepare_release(ff, flags, FUSE_RELEASE);
 313         __set_bit(FR_FORCE, &ff->reserved_req->flags);
 314         __clear_bit(FR_BACKGROUND, &ff->reserved_req->flags);
 315         fuse_request_send(ff->fc, ff->reserved_req);
 316         fuse_put_request(ff->fc, ff->reserved_req);
 317         kfree(ff);
 318 }
 319 EXPORT_SYMBOL_GPL(fuse_sync_release);
 320
 321 /*
 322  * Scramble the ID space with XTEA, so that the value of the files_struct
 323  * pointer is not exposed to userspace.
 324  */
 325 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 326 {
 327         u32 *k = fc->scramble_key;
 328         u64 v = (unsigned long) id;
 329         u32 v0 = v;
 330         u32 v1 = v >> 32;
 331         u32 sum = 0;
 332         int i;
 333
 334         for (i = 0; i < 32; i++) {
 335                 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
 336                 sum += 0x9E3779B9;
 337                 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
 338         }
 339
 340         return (u64) v0 + ((u64) v1 << 32);
 341 }
 342
 343 /*
 344  * Check if any page in a range is under writeback
 345  *
 346  * This is currently done by walking the list of writepage requests
 347  * for the inode, which can be pretty inefficient.
 348  */
 349 static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
 350                                    pgoff_t idx_to)
 351 {
 352         struct fuse_conn *fc = get_fuse_conn(inode);
 353         struct fuse_inode *fi = get_fuse_inode(inode);
 354         struct fuse_req *req;
 355         bool found = false;
 356
 357         spin_lock(&fc->lock);
 358         list_for_each_entry(req, &fi->writepages, writepages_entry) {
 359                 pgoff_t curr_index;
 360
 361                 BUG_ON(req->inode != inode);
 362                 curr_index = req->misc.write.in.offset >> PAGE_SHIFT;
 363                 if (idx_from < curr_index + req->num_pages &&
 364                     curr_index <= idx_to) {
 365                         found = true;
 366                         break;
 367                 }
 368         }
 369         spin_unlock(&fc->lock);
 370
 371         return found;
 372 }
 373
 374 static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
 375 {
 376         return fuse_range_is_writeback(inode, index, index);
 377 }
 378
 379 /*
 380  * Wait for page writeback to be completed.
 381  *
 382  * Since fuse doesn't rely on the VM writeback tracking, this has to
 383  * use some other means.
 384  */
 385 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
 386 {
 387         struct fuse_inode *fi = get_fuse_inode(inode);
 388
 389         wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
 390         return 0;
 391 }
 392
 393 /*
 394  * Wait for all pending writepages on the inode to finish.
 395  *
 396  * This is currently done by blocking further writes with FUSE_NOWRITE
 397  * and waiting for all sent writes to complete.
 398  *
 399  * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
 400  * could conflict with truncation.
 401  */
 402 static void fuse_sync_writes(struct inode *inode)
 403 {
 404         fuse_set_nowrite(inode);
 405         fuse_release_nowrite(inode);
 406 }
 407
 408 static int fuse_flush(struct file *file, fl_owner_t id)
 409 {
 410         struct inode *inode = file_inode(file);
 411         struct fuse_conn *fc = get_fuse_conn(inode);
 412         struct fuse_file *ff = file->private_data;
 413         struct fuse_req *req;
 414         struct fuse_flush_in inarg;
 415         int err;
 416
 417         if (fuse_is_bad(inode))
 418                 return -EIO;
 419
 420         if (fc->no_flush)
 421                 return 0;
 422
 423         err = write_inode_now(inode, 1);
 424         if (err)
 425                 return err;
 426
 427         inode_lock(inode);
 428         fuse_sync_writes(inode);
 429         inode_unlock(inode);
 430
 431         err = filemap_check_errors(file->f_mapping);
 432         if (err)
 433                 return err;
 434
 435         req = fuse_get_req_nofail_nopages(fc, file);
 436         memset(&inarg, 0, sizeof(inarg));
 437         inarg.fh = ff->fh;
 438         inarg.lock_owner = fuse_lock_owner_id(fc, id);
 439         req->in.h.opcode = FUSE_FLUSH;
 440         req->in.h.nodeid = get_node_id(inode);
 441         req->in.numargs = 1;
 442         req->in.args[0].size = sizeof(inarg);
 443         req->in.args[0].value = &inarg;
 444         __set_bit(FR_FORCE, &req->flags);
 445         fuse_request_send(fc, req);
 446         err = req->out.h.error;
 447         fuse_put_request(fc, req);
 448         if (err == -ENOSYS) {
 449                 fc->no_flush = 1;
 450                 err = 0;
 451         }
 452         return err;
 453 }
 454
 455 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 456                       int datasync, int isdir)
 457 {
 458         struct inode *inode = file->f_mapping->host;
 459         struct fuse_conn *fc = get_fuse_conn(inode);
 460         struct fuse_file *ff = file->private_data;
 461         FUSE_ARGS(args);
 462         struct fuse_fsync_in inarg;
 463         int err;
 464
 465         if (fuse_is_bad(inode))
 466                 return -EIO;
 467
 468         inode_lock(inode);
 469
 470         /*
 471          * Start writeback against all dirty pages of the inode, then
 472          * wait for all outstanding writes, before sending the FSYNC
 473          * request.
 474          */
 475         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 476         if (err)
 477                 goto out;
 478
 479         fuse_sync_writes(inode);
 480
 481         /*
 482          * Due to implementation of fuse writeback
 483          * filemap_write_and_wait_range() does not catch errors.
 484          * We have to do this directly after fuse_sync_writes()
 485          */
 486         err = filemap_check_errors(file->f_mapping);
 487         if (err)
 488                 goto out;
 489
 490         err = sync_inode_metadata(inode, 1);
 491         if (err)
 492                 goto out;
 493
 494         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 495                 goto out;
 496
 497         memset(&inarg, 0, sizeof(inarg));
 498         inarg.fh = ff->fh;
 499         inarg.fsync_flags = datasync ? 1 : 0;
 500         args.in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 501         args.in.h.nodeid = get_node_id(inode);
 502         args.in.numargs = 1;
 503         args.in.args[0].size = sizeof(inarg);
 504         args.in.args[0].value = &inarg;
 505         err = fuse_simple_request(fc, &args);
 506         if (err == -ENOSYS) {
 507                 if (isdir)
 508                         fc->no_fsyncdir = 1;
 509                 else
 510                         fc->no_fsync = 1;
 511                 err = 0;
 512         }
 513 out:
 514         inode_unlock(inode);
 515         return err;
 516 }
 517
 518 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
 519                       int datasync)
 520 {
 521         return fuse_fsync_common(file, start, end, datasync, 0);
 522 }
 523
 524 void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
 525                     size_t count, int opcode)
 526 {
 527         struct fuse_read_in *inarg = &req->misc.read.in;
 528         struct fuse_file *ff = file->private_data;
 529
 530         inarg->fh = ff->fh;
 531         inarg->offset = pos;
 532         inarg->size = count;
 533         inarg->flags = file->f_flags;
 534         req->in.h.opcode = opcode;
 535         req->in.h.nodeid = ff->nodeid;
 536         req->in.numargs = 1;
 537         req->in.args[0].size = sizeof(struct fuse_read_in);
 538         req->in.args[0].value = inarg;
 539         req->out.argvar = 1;
 540         req->out.numargs = 1;
 541         req->out.args[0].size = count;
 542 }
 543
 544 static void fuse_release_user_pages(struct fuse_req *req, bool should_dirty)
 545 {
 546         unsigned i;
 547
 548         for (i = 0; i < req->num_pages; i++) {
 549                 struct page *page = req->pages[i];
 550                 if (should_dirty)
 551                         set_page_dirty_lock(page);
 552                 put_page(page);
 553         }
 554 }
 555
 556 static void fuse_io_release(struct kref *kref)
 557 {
 558         kfree(container_of(kref, struct fuse_io_priv, refcnt));
 559 }
 560
 561 static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
 562 {
 563         if (io->err)
 564                 return io->err;
 565
 566         if (io->bytes >= 0 && io->write)
 567                 return -EIO;
 568
 569         return io->bytes < 0 ? io->size : io->bytes;
 570 }
 571
 572 /**
 573  * In case of short read, the caller sets 'pos' to the position of
 574  * actual end of fuse request in IO request. Otherwise, if bytes_requested
 575  * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
 576  *
 577  * An example:
 578  * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
 579  * both submitted asynchronously. The first of them was ACKed by userspace as
 580  * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
 581  * second request was ACKed as short, e.g. only 1K was read, resulting in
 582  * pos == 33K.
 583  *
 584  * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
 585  * will be equal to the length of the longest contiguous fragment of
 586  * transferred data starting from the beginning of IO request.
 587  */
 588 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
 589 {
 590         int left;
 591
 592         spin_lock(&io->lock);
 593         if (err)
 594                 io->err = io->err ? : err;
 595         else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
 596                 io->bytes = pos;
 597
 598         left = --io->reqs;
 599         if (!left && io->blocking)
 600                 complete(io->done);
 601         spin_unlock(&io->lock);
 602
 603         if (!left && !io->blocking) {
 604                 ssize_t res = fuse_get_res_by_io(io);
 605
 606                 if (res >= 0) {
 607                         struct inode *inode = file_inode(io->iocb->ki_filp);
 608                         struct fuse_conn *fc = get_fuse_conn(inode);
 609                         struct fuse_inode *fi = get_fuse_inode(inode);
 610
 611                         spin_lock(&fc->lock);
 612                         fi->attr_version = ++fc->attr_version;
 613                         spin_unlock(&fc->lock);
 614                 }
 615
 616                 io->iocb->ki_complete(io->iocb, res, 0);
 617         }
 618
 619         kref_put(&io->refcnt, fuse_io_release);
 620 }
 621
 622 static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
 623 {
 624         struct fuse_io_priv *io = req->io;
 625         ssize_t pos = -1;
 626
 627         fuse_release_user_pages(req, !io->write);
 628
 629         if (io->write) {
 630                 if (req->misc.write.in.size != req->misc.write.out.size)
 631                         pos = req->misc.write.in.offset - io->offset +
 632                                 req->misc.write.out.size;
 633         } else {
 634                 if (req->misc.read.in.size != req->out.args[0].size)
 635                         pos = req->misc.read.in.offset - io->offset +
 636                                 req->out.args[0].size;
 637         }
 638
 639         fuse_aio_complete(io, req->out.h.error, pos);
 640 }
 641
 642 static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
 643                 size_t num_bytes, struct fuse_io_priv *io)
 644 {
 645         spin_lock(&io->lock);
 646         kref_get(&io->refcnt);
 647         io->size += num_bytes;
 648         io->reqs++;
 649         spin_unlock(&io->lock);
 650
 651         req->io = io;
 652         req->end = fuse_aio_complete_req;
 653
 654         __fuse_get_request(req);
 655         fuse_request_send_background(fc, req);
 656
 657         return num_bytes;
 658 }
 659
 660 static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
 661                              loff_t pos, size_t count, fl_owner_t owner)
 662 {
 663         struct file *file = io->file;
 664         struct fuse_file *ff = file->private_data;
 665         struct fuse_conn *fc = ff->fc;
 666
 667         fuse_read_fill(req, file, pos, count, FUSE_READ);
 668         if (owner != NULL) {
 669                 struct fuse_read_in *inarg = &req->misc.read.in;
 670
 671                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
 672                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 673         }
 674
 675         if (io->async)
 676                 return fuse_async_req_send(fc, req, count, io);
 677
 678         fuse_request_send(fc, req);
 679         return req->out.args[0].size;
 680 }
 681
 682 static void fuse_read_update_size(struct inode *inode, loff_t size,
 683                                   u64 attr_ver)
 684 {
 685         struct fuse_conn *fc = get_fuse_conn(inode);
 686         struct fuse_inode *fi = get_fuse_inode(inode);
 687
 688         spin_lock(&fc->lock);
 689         if (attr_ver == fi->attr_version && size < inode->i_size &&
 690             !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
 691                 fi->attr_version = ++fc->attr_version;
 692                 i_size_write(inode, size);
 693         }
 694         spin_unlock(&fc->lock);
 695 }
 696
 697 static void fuse_short_read(struct fuse_req *req, struct inode *inode,
 698                             u64 attr_ver)
 699 {
 700         size_t num_read = req->out.args[0].size;
 701         struct fuse_conn *fc = get_fuse_conn(inode);
 702
 703         if (fc->writeback_cache) {
 704                 /*
 705                  * A hole in a file. Some data after the hole are in page cache,
 706                  * but have not reached the client fs yet. So, the hole is not
 707                  * present there.
 708                  */
 709                 int i;
 710                 int start_idx = num_read >> PAGE_SHIFT;
 711                 size_t off = num_read & (PAGE_SIZE - 1);
 712
 713                 for (i = start_idx; i < req->num_pages; i++) {
 714                         zero_user_segment(req->pages[i], off, PAGE_SIZE);
 715                         off = 0;
 716                 }
 717         } else {
 718                 loff_t pos = page_offset(req->pages[0]) + num_read;
 719                 fuse_read_update_size(inode, pos, attr_ver);
 720         }
 721 }
 722
 723 static int fuse_do_readpage(struct file *file, struct page *page)
 724 {
 725         struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
 726         struct inode *inode = page->mapping->host;
 727         struct fuse_conn *fc = get_fuse_conn(inode);
 728         struct fuse_req *req;
 729         size_t num_read;
 730         loff_t pos = page_offset(page);
 731         size_t count = PAGE_SIZE;
 732         u64 attr_ver;
 733         int err;
 734
 735         /*
 736          * Page writeback can extend beyond the lifetime of the
 737          * page-cache page, so make sure we read a properly synced
 738          * page.
 739          */
 740         fuse_wait_on_page_writeback(inode, page->index);
 741
 742         req = fuse_get_req(fc, 1);
 743         if (IS_ERR(req))
 744                 return PTR_ERR(req);
 745
 746         attr_ver = fuse_get_attr_version(fc);
 747
 748         req->out.page_zeroing = 1;
 749         req->out.argpages = 1;
 750         req->num_pages = 1;
 751         req->pages[0] = page;
 752         req->page_descs[0].length = count;
 753         num_read = fuse_send_read(req, &io, pos, count, NULL);
 754         err = req->out.h.error;
 755
 756         if (!err) {
 757                 /*
 758                  * Short read means EOF.  If file size is larger, truncate it
 759                  */
 760                 if (num_read < count)
 761                         fuse_short_read(req, inode, attr_ver);
 762
 763                 SetPageUptodate(page);
 764         }
 765
 766         fuse_put_request(fc, req);
 767
 768         return err;
 769 }
 770
 771 static int fuse_readpage(struct file *file, struct page *page)
 772 {
 773         struct inode *inode = page->mapping->host;
 774         int err;
 775
 776         err = -EIO;
 777         if (fuse_is_bad(inode))
 778                 goto out;
 779
 780         err = fuse_do_readpage(file, page);
 781         fuse_invalidate_atime(inode);
 782  out:
 783         unlock_page(page);
 784         return err;
 785 }
 786
 787 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 788 {
 789         int i;
 790         size_t count = req->misc.read.in.size;
 791         size_t num_read = req->out.args[0].size;
 792         struct address_space *mapping = NULL;
 793
 794         for (i = 0; mapping == NULL && i < req->num_pages; i++)
 795                 mapping = req->pages[i]->mapping;
 796
 797         if (mapping) {
 798                 struct inode *inode = mapping->host;
 799
 800                 /*
 801                  * Short read means EOF. If file size is larger, truncate it
 802                  */
 803                 if (!req->out.h.error && num_read < count)
 804                         fuse_short_read(req, inode, req->misc.read.attr_ver);
 805
 806                 fuse_invalidate_atime(inode);
 807         }
 808
 809         for (i = 0; i < req->num_pages; i++) {
 810                 struct page *page = req->pages[i];
 811                 if (!req->out.h.error)
 812                         SetPageUptodate(page);
 813                 else
 814                         SetPageError(page);
 815                 unlock_page(page);
 816                 put_page(page);
 817         }
 818         if (req->ff)
 819                 fuse_file_put(req->ff, false);
 820 }
 821
 822 static void fuse_send_readpages(struct fuse_req *req, struct file *file)
 823 {
 824         struct fuse_file *ff = file->private_data;
 825         struct fuse_conn *fc = ff->fc;
 826         loff_t pos = page_offset(req->pages[0]);
 827         size_t count = req->num_pages << PAGE_SHIFT;
 828
 829         req->out.argpages = 1;
 830         req->out.page_zeroing = 1;
 831         req->out.page_replace = 1;
 832         fuse_read_fill(req, file, pos, count, FUSE_READ);
 833         req->misc.read.attr_ver = fuse_get_attr_version(fc);
 834         if (fc->async_read) {
 835                 req->ff = fuse_file_get(ff);
 836                 req->end = fuse_readpages_end;
 837                 fuse_request_send_background(fc, req);
 838         } else {
 839                 fuse_request_send(fc, req);
 840                 fuse_readpages_end(fc, req);
 841                 fuse_put_request(fc, req);
 842         }
 843 }
 844
 845 struct fuse_fill_data {
 846         struct fuse_req *req;
 847         struct file *file;
 848         struct inode *inode;
 849         unsigned nr_pages;
 850 };
 851
 852 static int fuse_readpages_fill(void *_data, struct page *page)
 853 {
 854         struct fuse_fill_data *data = _data;
 855         struct fuse_req *req = data->req;
 856         struct inode *inode = data->inode;
 857         struct fuse_conn *fc = get_fuse_conn(inode);
 858
 859         fuse_wait_on_page_writeback(inode, page->index);
 860
 861         if (req->num_pages &&
 862             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 863              (req->num_pages + 1) * PAGE_SIZE > fc->max_read ||
 864              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 865                 int nr_alloc = min_t(unsigned, data->nr_pages,
 866                                      FUSE_MAX_PAGES_PER_REQ);
 867                 fuse_send_readpages(req, data->file);
 868                 if (fc->async_read)
 869                         req = fuse_get_req_for_background(fc, nr_alloc);
 870                 else
 871                         req = fuse_get_req(fc, nr_alloc);
 872
 873                 data->req = req;
 874                 if (IS_ERR(req)) {
 875                         unlock_page(page);
 876                         return PTR_ERR(req);
 877                 }
 878         }
 879
 880         if (WARN_ON(req->num_pages >= req->max_pages)) {
 881                 unlock_page(page);
 882                 fuse_put_request(fc, req);
 883                 return -EIO;
 884         }
 885
 886         get_page(page);
 887         req->pages[req->num_pages] = page;
 888         req->page_descs[req->num_pages].length = PAGE_SIZE;
 889         req->num_pages++;
 890         data->nr_pages--;
 891         return 0;
 892 }
 893
 894 static int fuse_readpages(struct file *file, struct address_space *mapping,
 895                           struct list_head *pages, unsigned nr_pages)
 896 {
 897         struct inode *inode = mapping->host;
 898         struct fuse_conn *fc = get_fuse_conn(inode);
 899         struct fuse_fill_data data;
 900         int err;
 901         int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
 902
 903         err = -EIO;
 904         if (fuse_is_bad(inode))
 905                 goto out;
 906
 907         data.file = file;
 908         data.inode = inode;
 909         if (fc->async_read)
 910                 data.req = fuse_get_req_for_background(fc, nr_alloc);
 911         else
 912                 data.req = fuse_get_req(fc, nr_alloc);
 913         data.nr_pages = nr_pages;
 914         err = PTR_ERR(data.req);
 915         if (IS_ERR(data.req))
 916                 goto out;
 917
 918         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 919         if (!err) {
 920                 if (data.req->num_pages)
 921                         fuse_send_readpages(data.req, file);
 922                 else
 923                         fuse_put_request(fc, data.req);
 924         }
 925 out:
 926         return err;
 927 }
 928
 929 static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 930 {
 931         struct inode *inode = iocb->ki_filp->f_mapping->host;
 932         struct fuse_conn *fc = get_fuse_conn(inode);
 933
 934         if (fuse_is_bad(inode))
 935                 return -EIO;
 936
 937         /*
 938          * In auto invalidate mode, always update attributes on read.
 939          * Otherwise, only update if we attempt to read past EOF (to ensure
 940          * i_size is up to date).
 941          */
 942         if (fc->auto_inval_data ||
 943             (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
 944                 int err;
 945                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 946                 if (err)
 947                         return err;
 948         }
 949
 950         return generic_file_read_iter(iocb, to);
 951 }
 952
 953 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 954                             loff_t pos, size_t count)
 955 {
 956         struct fuse_write_in *inarg = &req->misc.write.in;
 957         struct fuse_write_out *outarg = &req->misc.write.out;
 958
 959         inarg->fh = ff->fh;
 960         inarg->offset = pos;
 961         inarg->size = count;
 962         req->in.h.opcode = FUSE_WRITE;
 963         req->in.h.nodeid = ff->nodeid;
 964         req->in.numargs = 2;
 965         if (ff->fc->minor < 9)
 966                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 967         else
 968                 req->in.args[0].size = sizeof(struct fuse_write_in);
 969         req->in.args[0].value = inarg;
 970         req->in.args[1].size = count;
 971         req->out.numargs = 1;
 972         req->out.args[0].size = sizeof(struct fuse_write_out);
 973         req->out.args[0].value = outarg;
 974 }
 975
 976 static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
 977                               loff_t pos, size_t count, fl_owner_t owner)
 978 {
 979         struct file *file = io->file;
 980         struct fuse_file *ff = file->private_data;
 981         struct fuse_conn *fc = ff->fc;
 982         struct fuse_write_in *inarg = &req->misc.write.in;
 983
 984         fuse_write_fill(req, ff, pos, count);
 985         inarg->flags = file->f_flags;
 986         if (owner != NULL) {
 987                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 988                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 989         }
 990
 991         if (io->async)
 992                 return fuse_async_req_send(fc, req, count, io);
 993
 994         fuse_request_send(fc, req);
 995         return req->misc.write.out.size;
 996 }
 997
 998 bool fuse_write_update_size(struct inode *inode, loff_t pos)
 999 {
1000         struct fuse_conn *fc = get_fuse_conn(inode);
1001         struct fuse_inode *fi = get_fuse_inode(inode);
1002         bool ret = false;
1003
1004         spin_lock(&fc->lock);
1005         fi->attr_version = ++fc->attr_version;
1006         if (pos > inode->i_size) {
1007                 i_size_write(inode, pos);
1008                 ret = true;
1009         }
1010         spin_unlock(&fc->lock);
1011
1012         return ret;
1013 }
1014
1015 static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
1016                                     struct inode *inode, loff_t pos,
1017                                     size_t count)
1018 {
1019         size_t res;
1020         unsigned offset;
1021         unsigned i;
1022         struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
1023
1024         for (i = 0; i < req->num_pages; i++)
1025                 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
1026
1027         res = fuse_send_write(req, &io, pos, count, NULL);
1028
1029         offset = req->page_descs[0].offset;
1030         count = res;
1031         for (i = 0; i < req->num_pages; i++) {
1032                 struct page *page = req->pages[i];
1033
1034                 if (!req->out.h.error && !offset && count >= PAGE_SIZE)
1035                         SetPageUptodate(page);
1036
1037                 if (count > PAGE_SIZE - offset)
1038                         count -= PAGE_SIZE - offset;
1039                 else
1040                         count = 0;
1041                 offset = 0;
1042
1043                 unlock_page(page);
1044                 put_page(page);
1045         }
1046
1047         return res;
1048 }
1049
1050 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
1051                                struct address_space *mapping,
1052                                struct iov_iter *ii, loff_t pos)
1053 {
1054         struct fuse_conn *fc = get_fuse_conn(mapping->host);
1055         unsigned offset = pos & (PAGE_SIZE - 1);
1056         size_t count = 0;
1057         int err;
1058
1059         req->in.argpages = 1;
1060         req->page_descs[0].offset = offset;
1061
1062         do {
1063                 size_t tmp;
1064                 struct page *page;
1065                 pgoff_t index = pos >> PAGE_SHIFT;
1066                 size_t bytes = min_t(size_t, PAGE_SIZE - offset,
1067                                      iov_iter_count(ii));
1068
1069                 bytes = min_t(size_t, bytes, fc->max_write - count);
1070
1071  again:
1072                 err = -EFAULT;
1073                 if (iov_iter_fault_in_readable(ii, bytes))
1074                         break;
1075
1076                 err = -ENOMEM;
1077                 page = grab_cache_page_write_begin(mapping, index, 0);
1078                 if (!page)
1079                         break;
1080
1081                 if (mapping_writably_mapped(mapping))
1082                         flush_dcache_page(page);
1083
1084                 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
1085                 flush_dcache_page(page);
1086
1087                 iov_iter_advance(ii, tmp);
1088                 if (!tmp) {
1089                         unlock_page(page);
1090                         put_page(page);
1091                         bytes = min(bytes, iov_iter_single_seg_count(ii));
1092                         goto again;
1093                 }
1094
1095                 err = 0;
1096                 req->pages[req->num_pages] = page;
1097                 req->page_descs[req->num_pages].length = tmp;
1098                 req->num_pages++;
1099
1100                 count += tmp;
1101                 pos += tmp;
1102                 offset += tmp;
1103                 if (offset == PAGE_SIZE)
1104                         offset = 0;
1105
1106                 if (!fc->big_writes)
1107                         break;
1108         } while (iov_iter_count(ii) && count < fc->max_write &&
1109                  req->num_pages < req->max_pages && offset == 0);
1110
1111         return count > 0 ? count : err;
1112 }
1113
1114 static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
1115 {
1116         return min_t(unsigned,
1117                      ((pos + len - 1) >> PAGE_SHIFT) -
1118                      (pos >> PAGE_SHIFT) + 1,
1119                      FUSE_MAX_PAGES_PER_REQ);
1120 }
1121
1122 static ssize_t fuse_perform_write(struct file *file,
1123                                   struct address_space *mapping,
1124                                   struct iov_iter *ii, loff_t pos)
1125 {
1126         struct inode *inode = mapping->host;
1127         struct fuse_conn *fc = get_fuse_conn(inode);
1128         struct fuse_inode *fi = get_fuse_inode(inode);
1129         int err = 0;
1130         ssize_t res = 0;
1131
1132         if (fuse_is_bad(inode))
1133                 return -EIO;
1134
1135         if (inode->i_size < pos + iov_iter_count(ii))
1136                 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1137
1138         do {
1139                 struct fuse_req *req;
1140                 ssize_t count;
1141                 unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
1142
1143                 req = fuse_get_req(fc, nr_pages);
1144                 if (IS_ERR(req)) {
1145                         err = PTR_ERR(req);
1146                         break;
1147                 }
1148
1149                 count = fuse_fill_write_pages(req, mapping, ii, pos);
1150                 if (count <= 0) {
1151                         err = count;
1152                 } else {
1153                         size_t num_written;
1154
1155                         num_written = fuse_send_write_pages(req, file, inode,
1156                                                             pos, count);
1157                         err = req->out.h.error;
1158                         if (!err) {
1159                                 res += num_written;
1160                                 pos += num_written;
1161
1162                                 /* break out of the loop on short write */
1163                                 if (num_written != count)
1164                                         err = -EIO;
1165                         }
1166                 }
1167                 fuse_put_request(fc, req);
1168         } while (!err && iov_iter_count(ii));
1169
1170         if (res > 0)
1171                 fuse_write_update_size(inode, pos);
1172
1173         clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1174         fuse_invalidate_attr(inode);
1175
1176         return res > 0 ? res : err;
1177 }
1178
1179 static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1180 {
1181         struct file *file = iocb->ki_filp;
1182         struct address_space *mapping = file->f_mapping;
1183         ssize_t written = 0;
1184         ssize_t written_buffered = 0;
1185         struct inode *inode = mapping->host;
1186         ssize_t err;
1187         loff_t endbyte = 0;
1188
1189         if (fuse_is_bad(inode))
1190                 return -EIO;
1191
1192         if (get_fuse_conn(inode)->writeback_cache) {
1193                 /* Update size (EOF optimization) and mode (SUID clearing) */
1194                 err = fuse_update_attributes(mapping->host, NULL, file, NULL);
1195                 if (err)
1196                         return err;
1197
1198                 return generic_file_write_iter(iocb, from);
1199         }
1200
1201         inode_lock(inode);
1202
1203         /* We can write back this queue in page reclaim */
1204         current->backing_dev_info = inode_to_bdi(inode);
1205
1206         err = generic_write_checks(iocb, from);
1207         if (err <= 0)
1208                 goto out;
1209
1210         err = file_remove_privs(file);
1211         if (err)
1212                 goto out;
1213
1214         err = file_update_time(file);
1215         if (err)
1216                 goto out;
1217
1218         if (iocb->ki_flags & IOCB_DIRECT) {
1219                 loff_t pos = iocb->ki_pos;
1220                 written = generic_file_direct_write(iocb, from);
1221                 if (written < 0 || !iov_iter_count(from))
1222                         goto out;
1223
1224                 pos += written;
1225
1226                 written_buffered = fuse_perform_write(file, mapping, from, pos);
1227                 if (written_buffered < 0) {
1228                         err = written_buffered;
1229                         goto out;
1230                 }
1231                 endbyte = pos + written_buffered - 1;
1232
1233                 err = filemap_write_and_wait_range(file->f_mapping, pos,
1234                                                    endbyte);
1235                 if (err)
1236                         goto out;
1237
1238                 invalidate_mapping_pages(file->f_mapping,
1239                                          pos >> PAGE_SHIFT,
1240                                          endbyte >> PAGE_SHIFT);
1241
1242                 written += written_buffered;
1243                 iocb->ki_pos = pos + written_buffered;
1244         } else {
1245                 written = fuse_perform_write(file, mapping, from, iocb->ki_pos);
1246                 if (written >= 0)
1247                         iocb->ki_pos += written;
1248         }
1249 out:
1250         current->backing_dev_info = NULL;
1251         inode_unlock(inode);
1252
1253         return written ? written : err;
1254 }
1255
1256 static inline void fuse_page_descs_length_init(struct fuse_req *req,
1257                 unsigned index, unsigned nr_pages)
1258 {
1259         int i;
1260
1261         for (i = index; i < index + nr_pages; i++)
1262                 req->page_descs[i].length = PAGE_SIZE -
1263                         req->page_descs[i].offset;
1264 }
1265
1266 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1267 {
1268         return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1269 }
1270
1271 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1272                                         size_t max_size)
1273 {
1274         return min(iov_iter_single_seg_count(ii), max_size);
1275 }
1276
1277 static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1278                                size_t *nbytesp, int write)
1279 {
1280         size_t nbytes = 0;  /* # bytes already packed in req */
1281         ssize_t ret = 0;
1282
1283         /* Special case for kernel I/O: can copy directly into the buffer */
1284         if (ii->type & ITER_KVEC) {
1285                 unsigned long user_addr = fuse_get_user_addr(ii);
1286                 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1287
1288                 if (write)
1289                         req->in.args[1].value = (void *) user_addr;
1290                 else
1291                         req->out.args[0].value = (void *) user_addr;
1292
1293                 iov_iter_advance(ii, frag_size);
1294                 *nbytesp = frag_size;
1295                 return 0;
1296         }
1297
1298         while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1299                 unsigned npages;
1300                 size_t start;
1301                 ret = iov_iter_get_pages(ii, &req->pages[req->num_pages],
1302                                         *nbytesp - nbytes,
1303                                         req->max_pages - req->num_pages,
1304                                         &start);
1305                 if (ret < 0)
1306                         break;
1307
1308                 iov_iter_advance(ii, ret);
1309                 nbytes += ret;
1310
1311                 ret += start;
1312                 npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
1313
1314                 req->page_descs[req->num_pages].offset = start;
1315                 fuse_page_descs_length_init(req, req->num_pages, npages);
1316
1317                 req->num_pages += npages;
1318                 req->page_descs[req->num_pages - 1].length -=
1319                         (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1320         }
1321
1322         if (write)
1323                 req->in.argpages = 1;
1324         else
1325                 req->out.argpages = 1;
1326
1327         *nbytesp = nbytes;
1328
1329         return ret < 0 ? ret : 0;
1330 }
1331
1332 static inline int fuse_iter_npages(const struct iov_iter *ii_p)
1333 {
1334         return iov_iter_npages(ii_p, FUSE_MAX_PAGES_PER_REQ);
1335 }
1336
1337 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1338                        loff_t *ppos, int flags)
1339 {
1340         int write = flags & FUSE_DIO_WRITE;
1341         bool should_dirty = !write && iter_is_iovec(iter);
1342         int cuse = flags & FUSE_DIO_CUSE;
1343         struct file *file = io->file;
1344         struct inode *inode = file->f_mapping->host;
1345         struct fuse_file *ff = file->private_data;
1346         struct fuse_conn *fc = ff->fc;
1347         size_t nmax = write ? fc->max_write : fc->max_read;
1348         loff_t pos = *ppos;
1349         size_t count = iov_iter_count(iter);
1350         pgoff_t idx_from = pos >> PAGE_SHIFT;
1351         pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
1352         ssize_t res = 0;
1353         struct fuse_req *req;
1354         int err = 0;
1355
1356         if (io->async)
1357                 req = fuse_get_req_for_background(fc, fuse_iter_npages(iter));
1358         else
1359                 req = fuse_get_req(fc, fuse_iter_npages(iter));
1360         if (IS_ERR(req))
1361                 return PTR_ERR(req);
1362
1363         if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1364                 if (!write)
1365                         inode_lock(inode);
1366                 fuse_sync_writes(inode);
1367                 if (!write)
1368                         inode_unlock(inode);
1369         }
1370
1371         while (count) {
1372                 size_t nres;
1373                 fl_owner_t owner = current->files;
1374                 size_t nbytes = min(count, nmax);
1375                 err = fuse_get_user_pages(req, iter, &nbytes, write);
1376                 if (err && !nbytes)
1377                         break;
1378
1379                 if (write)
1380                         nres = fuse_send_write(req, io, pos, nbytes, owner);
1381                 else
1382                         nres = fuse_send_read(req, io, pos, nbytes, owner);
1383
1384                 if (!io->async)
1385                         fuse_release_user_pages(req, should_dirty);
1386                 if (req->out.h.error) {
1387                         err = req->out.h.error;
1388                         break;
1389                 } else if (nres > nbytes) {
1390                         res = 0;
1391                         err = -EIO;
1392                         break;
1393                 }
1394                 count -= nres;
1395                 res += nres;
1396                 pos += nres;
1397                 if (nres != nbytes)
1398                         break;
1399                 if (count) {
1400                         fuse_put_request(fc, req);
1401                         if (io->async)
1402                                 req = fuse_get_req_for_background(fc,
1403                                         fuse_iter_npages(iter));
1404                         else
1405                                 req = fuse_get_req(fc, fuse_iter_npages(iter));
1406                         if (IS_ERR(req))
1407                                 break;
1408                 }
1409         }
1410         if (!IS_ERR(req))
1411                 fuse_put_request(fc, req);
1412         if (res > 0)
1413                 *ppos = pos;
1414
1415         return res > 0 ? res : err;
1416 }
1417 EXPORT_SYMBOL_GPL(fuse_direct_io);
1418
1419 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1420                                   struct iov_iter *iter,
1421                                   loff_t *ppos)
1422 {
1423         ssize_t res;
1424         struct file *file = io->file;
1425         struct inode *inode = file_inode(file);
1426
1427         if (fuse_is_bad(inode))
1428                 return -EIO;
1429
1430         res = fuse_direct_io(io, iter, ppos, 0);
1431
1432         fuse_invalidate_attr(inode);
1433
1434         return res;
1435 }
1436
1437 static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
1438 {
1439         struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb->ki_filp);
1440         return __fuse_direct_read(&io, to, &iocb->ki_pos);
1441 }
1442
1443 static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
1444 {
1445         struct file *file = iocb->ki_filp;
1446         struct inode *inode = file_inode(file);
1447         struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
1448         ssize_t res;
1449
1450         if (fuse_is_bad(inode))
1451                 return -EIO;
1452
1453         /* Don't allow parallel writes to the same file */
1454         inode_lock(inode);
1455         res = generic_write_checks(iocb, from);
1456         if (res > 0)
1457                 res = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE);
1458         fuse_invalidate_attr(inode);
1459         if (res > 0)
1460                 fuse_write_update_size(inode, iocb->ki_pos);
1461         inode_unlock(inode);
1462
1463         return res;
1464 }
1465
1466 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1467 {
1468         int i;
1469
1470         for (i = 0; i < req->num_pages; i++)
1471                 __free_page(req->pages[i]);
1472
1473         if (req->ff)
1474                 fuse_file_put(req->ff, false);
1475 }
1476
1477 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1478 {
1479         struct inode *inode = req->inode;
1480         struct fuse_inode *fi = get_fuse_inode(inode);
1481         struct backing_dev_info *bdi = inode_to_bdi(inode);
1482         int i;
1483
1484         list_del(&req->writepages_entry);
1485         for (i = 0; i < req->num_pages; i++) {
1486                 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1487                 dec_node_page_state(req->pages[i], NR_WRITEBACK_TEMP);
1488                 wb_writeout_inc(&bdi->wb);
1489         }
1490         wake_up(&fi->page_waitq);
1491 }
1492
1493 /* Called under fc->lock, may release and reacquire it */
1494 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req,
1495                                 loff_t size)
1496 __releases(fc->lock)
1497 __acquires(fc->lock)
1498 {
1499         struct fuse_inode *fi = get_fuse_inode(req->inode);
1500         struct fuse_write_in *inarg = &req->misc.write.in;
1501         __u64 data_size = req->num_pages * PAGE_SIZE;
1502
1503         if (!fc->connected)
1504                 goto out_free;
1505
1506         if (inarg->offset + data_size <= size) {
1507                 inarg->size = data_size;
1508         } else if (inarg->offset < size) {
1509                 inarg->size = size - inarg->offset;
1510         } else {
1511                 /* Got truncated off completely */
1512                 goto out_free;
1513         }
1514
1515         req->in.args[1].size = inarg->size;
1516         fi->writectr++;
1517         fuse_request_send_background_locked(fc, req);
1518         return;
1519
1520  out_free:
1521         fuse_writepage_finish(fc, req);
1522         spin_unlock(&fc->lock);
1523         fuse_writepage_free(fc, req);
1524         fuse_put_request(fc, req);
1525         spin_lock(&fc->lock);
1526 }
1527
1528 /*
1529  * If fi->writectr is positive (no truncate or fsync going on) send
1530  * all queued writepage requests.
1531  *
1532  * Called with fc->lock
1533  */
1534 void fuse_flush_writepages(struct inode *inode)
1535 __releases(fc->lock)
1536 __acquires(fc->lock)
1537 {
1538         struct fuse_conn *fc = get_fuse_conn(inode);
1539         struct fuse_inode *fi = get_fuse_inode(inode);
1540         loff_t crop = i_size_read(inode);
1541         struct fuse_req *req;
1542
1543         while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1544                 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1545                 list_del_init(&req->list);
1546                 fuse_send_writepage(fc, req, crop);
1547         }
1548 }
1549
1550 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1551 {
1552         struct inode *inode = req->inode;
1553         struct fuse_inode *fi = get_fuse_inode(inode);
1554
1555         mapping_set_error(inode->i_mapping, req->out.h.error);
1556         spin_lock(&fc->lock);
1557         while (req->misc.write.next) {
1558                 struct fuse_conn *fc = get_fuse_conn(inode);
1559                 struct fuse_write_in *inarg = &req->misc.write.in;
1560                 struct fuse_req *next = req->misc.write.next;
1561                 req->misc.write.next = next->misc.write.next;
1562                 next->misc.write.next = NULL;
1563                 next->ff = fuse_file_get(req->ff);
1564                 list_add(&next->writepages_entry, &fi->writepages);
1565
1566                 /*
1567                  * Skip fuse_flush_writepages() to make it easy to crop requests
1568                  * based on primary request size.
1569                  *
1570                  * 1st case (trivial): there are no concurrent activities using
1571                  * fuse_set/release_nowrite.  Then we're on safe side because
1572                  * fuse_flush_writepages() would call fuse_send_writepage()
1573                  * anyway.
1574                  *
1575                  * 2nd case: someone called fuse_set_nowrite and it is waiting
1576                  * now for completion of all in-flight requests.  This happens
1577                  * rarely and no more than once per page, so this should be
1578                  * okay.
1579                  *
1580                  * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1581                  * of fuse_set_nowrite..fuse_release_nowrite section.  The fact
1582                  * that fuse_set_nowrite returned implies that all in-flight
1583                  * requests were completed along with all of their secondary
1584                  * requests.  Further primary requests are blocked by negative
1585                  * writectr.  Hence there cannot be any in-flight requests and
1586                  * no invocations of fuse_writepage_end() while we're in
1587                  * fuse_set_nowrite..fuse_release_nowrite section.
1588                  */
1589                 fuse_send_writepage(fc, next, inarg->offset + inarg->size);
1590         }
1591         fi->writectr--;
1592         fuse_writepage_finish(fc, req);
1593         spin_unlock(&fc->lock);
1594         fuse_writepage_free(fc, req);
1595 }
1596
1597 static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
1598                                                struct fuse_inode *fi)
1599 {
1600         struct fuse_file *ff = NULL;
1601
1602         spin_lock(&fc->lock);
1603         if (!list_empty(&fi->write_files)) {
1604                 ff = list_entry(fi->write_files.next, struct fuse_file,
1605                                 write_entry);
1606                 fuse_file_get(ff);
1607         }
1608         spin_unlock(&fc->lock);
1609
1610         return ff;
1611 }
1612
1613 static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
1614                                              struct fuse_inode *fi)
1615 {
1616         struct fuse_file *ff = __fuse_write_file_get(fc, fi);
1617         WARN_ON(!ff);
1618         return ff;
1619 }
1620
1621 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1622 {
1623         struct fuse_conn *fc = get_fuse_conn(inode);
1624         struct fuse_inode *fi = get_fuse_inode(inode);
1625         struct fuse_file *ff;
1626         int err;
1627
1628         ff = __fuse_write_file_get(fc, fi);
1629         err = fuse_flush_times(inode, ff);
1630         if (ff)
1631                 fuse_file_put(ff, 0);
1632
1633         return err;
1634 }
1635
1636 static int fuse_writepage_locked(struct page *page)
1637 {
1638         struct address_space *mapping = page->mapping;
1639         struct inode *inode = mapping->host;
1640         struct fuse_conn *fc = get_fuse_conn(inode);
1641         struct fuse_inode *fi = get_fuse_inode(inode);
1642         struct fuse_req *req;
1643         struct page *tmp_page;
1644         int error = -ENOMEM;
1645
1646         set_page_writeback(page);
1647
1648         req = fuse_request_alloc_nofs(1);
1649         if (!req)
1650                 goto err;
1651
1652         /* writeback always goes to bg_queue */
1653         __set_bit(FR_BACKGROUND, &req->flags);
1654         tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1655         if (!tmp_page)
1656                 goto err_free;
1657
1658         error = -EIO;
1659         req->ff = fuse_write_file_get(fc, fi);
1660         if (!req->ff)
1661                 goto err_nofile;
1662
1663         fuse_write_fill(req, req->ff, page_offset(page), 0);
1664
1665         copy_highpage(tmp_page, page);
1666         req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1667         req->misc.write.next = NULL;
1668         req->in.argpages = 1;
1669         req->num_pages = 1;
1670         req->pages[0] = tmp_page;
1671         req->page_descs[0].offset = 0;
1672         req->page_descs[0].length = PAGE_SIZE;
1673         req->end = fuse_writepage_end;
1674         req->inode = inode;
1675
1676         inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1677         inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1678
1679         spin_lock(&fc->lock);
1680         list_add(&req->writepages_entry, &fi->writepages);
1681         list_add_tail(&req->list, &fi->queued_writes);
1682         fuse_flush_writepages(inode);
1683         spin_unlock(&fc->lock);
1684
1685         end_page_writeback(page);
1686
1687         return 0;
1688
1689 err_nofile:
1690         __free_page(tmp_page);
1691 err_free:
1692         fuse_request_free(req);
1693 err:
1694         end_page_writeback(page);
1695         return error;
1696 }
1697
1698 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1699 {
1700         int err;
1701
1702         if (fuse_page_is_writeback(page->mapping->host, page->index)) {
1703                 /*
1704                  * ->writepages() should be called for sync() and friends.  We
1705                  * should only get here on direct reclaim and then we are
1706                  * allowed to skip a page which is already in flight
1707                  */
1708                 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
1709
1710                 redirty_page_for_writepage(wbc, page);
1711                 unlock_page(page);
1712                 return 0;
1713         }
1714
1715         err = fuse_writepage_locked(page);
1716         unlock_page(page);
1717
1718         return err;
1719 }
1720
1721 struct fuse_fill_wb_data {
1722         struct fuse_req *req;
1723         struct fuse_file *ff;
1724         struct inode *inode;
1725         struct page **orig_pages;
1726 };
1727
1728 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
1729 {
1730         struct fuse_req *req = data->req;
1731         struct inode *inode = data->inode;
1732         struct fuse_conn *fc = get_fuse_conn(inode);
1733         struct fuse_inode *fi = get_fuse_inode(inode);
1734         int num_pages = req->num_pages;
1735         int i;
1736
1737         req->ff = fuse_file_get(data->ff);
1738         spin_lock(&fc->lock);
1739         list_add_tail(&req->list, &fi->queued_writes);
1740         fuse_flush_writepages(inode);
1741         spin_unlock(&fc->lock);
1742
1743         for (i = 0; i < num_pages; i++)
1744                 end_page_writeback(data->orig_pages[i]);
1745 }
1746
1747 static bool fuse_writepage_in_flight(struct fuse_req *new_req,
1748                                      struct page *page)
1749 {
1750         struct fuse_conn *fc = get_fuse_conn(new_req->inode);
1751         struct fuse_inode *fi = get_fuse_inode(new_req->inode);
1752         struct fuse_req *tmp;
1753         struct fuse_req *old_req;
1754         bool found = false;
1755         pgoff_t curr_index;
1756
1757         BUG_ON(new_req->num_pages != 0);
1758
1759         spin_lock(&fc->lock);
1760         list_del(&new_req->writepages_entry);
1761         list_for_each_entry(old_req, &fi->writepages, writepages_entry) {
1762                 BUG_ON(old_req->inode != new_req->inode);
1763                 curr_index = old_req->misc.write.in.offset >> PAGE_SHIFT;
1764                 if (curr_index <= page->index &&
1765                     page->index < curr_index + old_req->num_pages) {
1766                         found = true;
1767                         break;
1768                 }
1769         }
1770         if (!found) {
1771                 list_add(&new_req->writepages_entry, &fi->writepages);
1772                 goto out_unlock;
1773         }
1774
1775         new_req->num_pages = 1;
1776         for (tmp = old_req; tmp != NULL; tmp = tmp->misc.write.next) {
1777                 BUG_ON(tmp->inode != new_req->inode);
1778                 curr_index = tmp->misc.write.in.offset >> PAGE_SHIFT;
1779                 if (tmp->num_pages == 1 &&
1780                     curr_index == page->index) {
1781                         old_req = tmp;
1782                 }
1783         }
1784
1785         if (old_req->num_pages == 1 && test_bit(FR_PENDING, &old_req->flags)) {
1786                 struct backing_dev_info *bdi = inode_to_bdi(page->mapping->host);
1787
1788                 copy_highpage(old_req->pages[0], page);
1789                 spin_unlock(&fc->lock);
1790
1791                 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1792                 dec_node_page_state(new_req->pages[0], NR_WRITEBACK_TEMP);
1793                 wb_writeout_inc(&bdi->wb);
1794                 fuse_writepage_free(fc, new_req);
1795                 fuse_request_free(new_req);
1796                 goto out;
1797         } else {
1798                 new_req->misc.write.next = old_req->misc.write.next;
1799                 old_req->misc.write.next = new_req;
1800         }
1801 out_unlock:
1802         spin_unlock(&fc->lock);
1803 out:
1804         return found;
1805 }
1806
1807 static int fuse_writepages_fill(struct page *page,
1808                 struct writeback_control *wbc, void *_data)
1809 {
1810         struct fuse_fill_wb_data *data = _data;
1811         struct fuse_req *req = data->req;
1812         struct inode *inode = data->inode;
1813         struct fuse_conn *fc = get_fuse_conn(inode);
1814         struct page *tmp_page;
1815         bool is_writeback;
1816         int err;
1817
1818         if (!data->ff) {
1819                 err = -EIO;
1820                 data->ff = fuse_write_file_get(fc, get_fuse_inode(inode));
1821                 if (!data->ff)
1822                         goto out_unlock;
1823         }
1824
1825         /*
1826          * Being under writeback is unlikely but possible.  For example direct
1827          * read to an mmaped fuse file will set the page dirty twice; once when
1828          * the pages are faulted with get_user_pages(), and then after the read
1829          * completed.
1830          */
1831         is_writeback = fuse_page_is_writeback(inode, page->index);
1832
1833         if (req && req->num_pages &&
1834             (is_writeback || req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
1835              (req->num_pages + 1) * PAGE_SIZE > fc->max_write ||
1836              data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) {
1837                 fuse_writepages_send(data);
1838                 data->req = NULL;
1839         }
1840         err = -ENOMEM;
1841         tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1842         if (!tmp_page)
1843                 goto out_unlock;
1844
1845         /*
1846          * The page must not be redirtied until the writeout is completed
1847          * (i.e. userspace has sent a reply to the write request).  Otherwise
1848          * there could be more than one temporary page instance for each real
1849          * page.
1850          *
1851          * This is ensured by holding the page lock in page_mkwrite() while
1852          * checking fuse_page_is_writeback().  We already hold the page lock
1853          * since clear_page_dirty_for_io() and keep it held until we add the
1854          * request to the fi->writepages list and increment req->num_pages.
1855          * After this fuse_page_is_writeback() will indicate that the page is
1856          * under writeback, so we can release the page lock.
1857          */
1858         if (data->req == NULL) {
1859                 struct fuse_inode *fi = get_fuse_inode(inode);
1860
1861                 err = -ENOMEM;
1862                 req = fuse_request_alloc_nofs(FUSE_MAX_PAGES_PER_REQ);
1863                 if (!req) {
1864                         __free_page(tmp_page);
1865                         goto out_unlock;
1866                 }
1867
1868                 fuse_write_fill(req, data->ff, page_offset(page), 0);
1869                 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1870                 req->misc.write.next = NULL;
1871                 req->in.argpages = 1;
1872                 __set_bit(FR_BACKGROUND, &req->flags);
1873                 req->num_pages = 0;
1874                 req->end = fuse_writepage_end;
1875                 req->inode = inode;
1876
1877                 spin_lock(&fc->lock);
1878                 list_add(&req->writepages_entry, &fi->writepages);
1879                 spin_unlock(&fc->lock);
1880
1881                 data->req = req;
1882         }
1883         set_page_writeback(page);
1884
1885         copy_highpage(tmp_page, page);
1886         req->pages[req->num_pages] = tmp_page;
1887         req->page_descs[req->num_pages].offset = 0;
1888         req->page_descs[req->num_pages].length = PAGE_SIZE;
1889
1890         inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1891         inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1892
1893         err = 0;
1894         if (is_writeback && fuse_writepage_in_flight(req, page)) {
1895                 end_page_writeback(page);
1896                 data->req = NULL;
1897                 goto out_unlock;
1898         }
1899         data->orig_pages[req->num_pages] = page;
1900
1901         /*
1902          * Protected by fc->lock against concurrent access by
1903          * fuse_page_is_writeback().
1904          */
1905         spin_lock(&fc->lock);
1906         req->num_pages++;
1907         spin_unlock(&fc->lock);
1908
1909 out_unlock:
1910         unlock_page(page);
1911
1912         return err;
1913 }
1914
1915 static int fuse_writepages(struct address_space *mapping,
1916                            struct writeback_control *wbc)
1917 {
1918         struct inode *inode = mapping->host;
1919         struct fuse_fill_wb_data data;
1920         int err;
1921
1922         err = -EIO;
1923         if (fuse_is_bad(inode))
1924                 goto out;
1925
1926         data.inode = inode;
1927         data.req = NULL;
1928         data.ff = NULL;
1929
1930         err = -ENOMEM;
1931         data.orig_pages = kcalloc(FUSE_MAX_PAGES_PER_REQ,
1932                                   sizeof(struct page *),
1933                                   GFP_NOFS);
1934         if (!data.orig_pages)
1935                 goto out;
1936
1937         err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
1938         if (data.req) {
1939                 /* Ignore errors if we can write at least one page */
1940                 BUG_ON(!data.req->num_pages);
1941                 fuse_writepages_send(&data);
1942                 err = 0;
1943         }
1944         if (data.ff)
1945                 fuse_file_put(data.ff, false);
1946
1947         kfree(data.orig_pages);
1948 out:
1949         return err;
1950 }
1951
1952 /*
1953  * It's worthy to make sure that space is reserved on disk for the write,
1954  * but how to implement it without killing performance need more thinking.
1955  */
1956 static int fuse_write_begin(struct file *file, struct address_space *mapping,
1957                 loff_t pos, unsigned len, unsigned flags,
1958                 struct page **pagep, void **fsdata)
1959 {
1960         pgoff_t index = pos >> PAGE_SHIFT;
1961         struct fuse_conn *fc = get_fuse_conn(file_inode(file));
1962         struct page *page;
1963         loff_t fsize;
1964         int err = -ENOMEM;
1965
1966         WARN_ON(!fc->writeback_cache);
1967
1968         page = grab_cache_page_write_begin(mapping, index, flags);
1969         if (!page)
1970                 goto error;
1971
1972         fuse_wait_on_page_writeback(mapping->host, page->index);
1973
1974         if (PageUptodate(page) || len == PAGE_SIZE)
1975                 goto success;
1976         /*
1977          * Check if the start this page comes after the end of file, in which
1978          * case the readpage can be optimized away.
1979          */
1980         fsize = i_size_read(mapping->host);
1981         if (fsize <= (pos & PAGE_MASK)) {
1982                 size_t off = pos & ~PAGE_MASK;
1983                 if (off)
1984                         zero_user_segment(page, 0, off);
1985                 goto success;
1986         }
1987         err = fuse_do_readpage(file, page);
1988         if (err)
1989                 goto cleanup;
1990 success:
1991         *pagep = page;
1992         return 0;
1993
1994 cleanup:
1995         unlock_page(page);
1996         put_page(page);
1997 error:
1998         return err;
1999 }
2000
2001 static int fuse_write_end(struct file *file, struct address_space *mapping,
2002                 loff_t pos, unsigned len, unsigned copied,
2003                 struct page *page, void *fsdata)
2004 {
2005         struct inode *inode = page->mapping->host;
2006
2007         /* Haven't copied anything?  Skip zeroing, size extending, dirtying. */
2008         if (!copied)
2009                 goto unlock;
2010
2011         if (!PageUptodate(page)) {
2012                 /* Zero any unwritten bytes at the end of the page */
2013                 size_t endoff = (pos + copied) & ~PAGE_MASK;
2014                 if (endoff)
2015                         zero_user_segment(page, endoff, PAGE_SIZE);
2016                 SetPageUptodate(page);
2017         }
2018
2019         fuse_write_update_size(inode, pos + copied);
2020         set_page_dirty(page);
2021
2022 unlock:
2023         unlock_page(page);
2024         put_page(page);
2025
2026         return copied;
2027 }
2028
2029 static int fuse_launder_page(struct page *page)
2030 {
2031         int err = 0;
2032         if (clear_page_dirty_for_io(page)) {
2033                 struct inode *inode = page->mapping->host;
2034                 err = fuse_writepage_locked(page);
2035                 if (!err)
2036                         fuse_wait_on_page_writeback(inode, page->index);
2037         }
2038         return err;
2039 }
2040
2041 /*
2042  * Write back dirty pages now, because there may not be any suitable
2043  * open files later
2044  */
2045 static void fuse_vma_close(struct vm_area_struct *vma)
2046 {
2047         filemap_write_and_wait(vma->vm_file->f_mapping);
2048 }
2049
2050 /*
2051  * Wait for writeback against this page to complete before allowing it
2052  * to be marked dirty again, and hence written back again, possibly
2053  * before the previous writepage completed.
2054  *
2055  * Block here, instead of in ->writepage(), so that the userspace fs
2056  * can only block processes actually operating on the filesystem.
2057  *
2058  * Otherwise unprivileged userspace fs would be able to block
2059  * unrelated:
2060  *
2061  * - page migration
2062  * - sync(2)
2063  * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2064  */
2065 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
2066 {
2067         struct page *page = vmf->page;
2068         struct inode *inode = file_inode(vma->vm_file);
2069
2070         file_update_time(vma->vm_file);
2071         lock_page(page);
2072         if (page->mapping != inode->i_mapping) {
2073                 unlock_page(page);
2074                 return VM_FAULT_NOPAGE;
2075         }
2076
2077         fuse_wait_on_page_writeback(inode, page->index);
2078         return VM_FAULT_LOCKED;
2079 }
2080
2081 static const struct vm_operations_struct fuse_file_vm_ops = {
2082         .close          = fuse_vma_close,
2083         .fault          = filemap_fault,
2084         .map_pages      = filemap_map_pages,
2085         .page_mkwrite   = fuse_page_mkwrite,
2086 };
2087
2088 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2089 {
2090         if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2091                 fuse_link_write_file(file);
2092
2093         file_accessed(file);
2094         vma->vm_ops = &fuse_file_vm_ops;
2095         return 0;
2096 }
2097
2098 static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
2099 {
2100         /* Can't provide the coherency needed for MAP_SHARED */
2101         if (vma->vm_flags & VM_MAYSHARE)
2102                 return -ENODEV;
2103
2104         invalidate_inode_pages2(file->f_mapping);
2105
2106         return generic_file_mmap(file, vma);
2107 }
2108
2109 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
2110                                   struct file_lock *fl)
2111 {
2112         switch (ffl->type) {
2113         case F_UNLCK:
2114                 break;
2115
2116         case F_RDLCK:
2117         case F_WRLCK:
2118                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2119                     ffl->end < ffl->start)
2120                         return -EIO;
2121
2122                 fl->fl_start = ffl->start;
2123                 fl->fl_end = ffl->end;
2124                 fl->fl_pid = ffl->pid;
2125                 break;
2126
2127         default:
2128                 return -EIO;
2129         }
2130         fl->fl_type = ffl->type;
2131         return 0;
2132 }
2133
2134 static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2135                          const struct file_lock *fl, int opcode, pid_t pid,
2136                          int flock, struct fuse_lk_in *inarg)
2137 {
2138         struct inode *inode = file_inode(file);
2139         struct fuse_conn *fc = get_fuse_conn(inode);
2140         struct fuse_file *ff = file->private_data;
2141
2142         memset(inarg, 0, sizeof(*inarg));
2143         inarg->fh = ff->fh;
2144         inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2145         inarg->lk.start = fl->fl_start;
2146         inarg->lk.end = fl->fl_end;
2147         inarg->lk.type = fl->fl_type;
2148         inarg->lk.pid = pid;
2149         if (flock)
2150                 inarg->lk_flags |= FUSE_LK_FLOCK;
2151         args->in.h.opcode = opcode;
2152         args->in.h.nodeid = get_node_id(inode);
2153         args->in.numargs = 1;
2154         args->in.args[0].size = sizeof(*inarg);
2155         args->in.args[0].value = inarg;
2156 }
2157
2158 static int fuse_getlk(struct file *file, struct file_lock *fl)
2159 {
2160         struct inode *inode = file_inode(file);
2161         struct fuse_conn *fc = get_fuse_conn(inode);
2162         FUSE_ARGS(args);
2163         struct fuse_lk_in inarg;
2164         struct fuse_lk_out outarg;
2165         int err;
2166
2167         fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2168         args.out.numargs = 1;
2169         args.out.args[0].size = sizeof(outarg);
2170         args.out.args[0].value = &outarg;
2171         err = fuse_simple_request(fc, &args);
2172         if (!err)
2173                 err = convert_fuse_file_lock(&outarg.lk, fl);
2174
2175         return err;
2176 }
2177
2178 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2179 {
2180         struct inode *inode = file_inode(file);
2181         struct fuse_conn *fc = get_fuse_conn(inode);
2182         FUSE_ARGS(args);
2183         struct fuse_lk_in inarg;
2184         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2185         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
2186         int err;
2187
2188         if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2189                 /* NLM needs asynchronous locks, which we don't support yet */
2190                 return -ENOLCK;
2191         }
2192
2193         /* Unlock on close is handled by the flush method */
2194         if (fl->fl_flags & FL_CLOSE)
2195                 return 0;
2196
2197         fuse_lk_fill(&args, file, fl, opcode, pid, flock, &inarg);
2198         err = fuse_simple_request(fc, &args);
2199
2200         /* locking is restartable */
2201         if (err == -EINTR)
2202                 err = -ERESTARTSYS;
2203
2204         return err;
2205 }
2206
2207 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2208 {
2209         struct inode *inode = file_inode(file);
2210         struct fuse_conn *fc = get_fuse_conn(inode);
2211         int err;
2212
2213         if (cmd == F_CANCELLK) {
2214                 err = 0;
2215         } else if (cmd == F_GETLK) {
2216                 if (fc->no_lock) {
2217                         posix_test_lock(file, fl);
2218                         err = 0;
2219                 } else
2220                         err = fuse_getlk(file, fl);
2221         } else {
2222                 if (fc->no_lock)
2223                         err = posix_lock_file(file, fl, NULL);
2224                 else
2225                         err = fuse_setlk(file, fl, 0);
2226         }
2227         return err;
2228 }
2229
2230 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2231 {
2232         struct inode *inode = file_inode(file);
2233         struct fuse_conn *fc = get_fuse_conn(inode);
2234         int err;
2235
2236         if (fc->no_flock) {
2237                 err = locks_lock_file_wait(file, fl);
2238         } else {
2239                 struct fuse_file *ff = file->private_data;
2240
2241                 /* emulate flock with POSIX locks */
2242                 ff->flock = true;
2243                 err = fuse_setlk(file, fl, 1);
2244         }
2245
2246         return err;
2247 }
2248
2249 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2250 {
2251         struct inode *inode = mapping->host;
2252         struct fuse_conn *fc = get_fuse_conn(inode);
2253         FUSE_ARGS(args);
2254         struct fuse_bmap_in inarg;
2255         struct fuse_bmap_out outarg;
2256         int err;
2257
2258         if (!inode->i_sb->s_bdev || fc->no_bmap)
2259                 return 0;
2260
2261         memset(&inarg, 0, sizeof(inarg));
2262         inarg.block = block;
2263         inarg.blocksize = inode->i_sb->s_blocksize;
2264         args.in.h.opcode = FUSE_BMAP;
2265         args.in.h.nodeid = get_node_id(inode);
2266         args.in.numargs = 1;
2267         args.in.args[0].size = sizeof(inarg);
2268         args.in.args[0].value = &inarg;
2269         args.out.numargs = 1;
2270         args.out.args[0].size = sizeof(outarg);
2271         args.out.args[0].value = &outarg;
2272         err = fuse_simple_request(fc, &args);
2273         if (err == -ENOSYS)
2274                 fc->no_bmap = 1;
2275
2276         return err ? 0 : outarg.block;
2277 }
2278
2279 static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2280 {
2281         struct inode *inode = file->f_mapping->host;
2282         struct fuse_conn *fc = get_fuse_conn(inode);
2283         struct fuse_file *ff = file->private_data;
2284         FUSE_ARGS(args);
2285         struct fuse_lseek_in inarg = {
2286                 .fh = ff->fh,
2287                 .offset = offset,
2288                 .whence = whence
2289         };
2290         struct fuse_lseek_out outarg;
2291         int err;
2292
2293         if (fc->no_lseek)
2294                 goto fallback;
2295
2296         args.in.h.opcode = FUSE_LSEEK;
2297         args.in.h.nodeid = ff->nodeid;
2298         args.in.numargs = 1;
2299         args.in.args[0].size = sizeof(inarg);
2300         args.in.args[0].value = &inarg;
2301         args.out.numargs = 1;
2302         args.out.args[0].size = sizeof(outarg);
2303         args.out.args[0].value = &outarg;
2304         err = fuse_simple_request(fc, &args);
2305         if (err) {
2306                 if (err == -ENOSYS) {
2307                         fc->no_lseek = 1;
2308                         goto fallback;
2309                 }
2310                 return err;
2311         }
2312
2313         return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2314
2315 fallback:
2316         err = fuse_update_attributes(inode, NULL, file, NULL);
2317         if (!err)
2318                 return generic_file_llseek(file, offset, whence);
2319         else
2320                 return err;
2321 }
2322
2323 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2324 {
2325         loff_t retval;
2326         struct inode *inode = file_inode(file);
2327
2328         switch (whence) {
2329         case SEEK_SET:
2330         case SEEK_CUR:
2331                  /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2332                 retval = generic_file_llseek(file, offset, whence);
2333                 break;
2334         case SEEK_END:
2335                 inode_lock(inode);
2336                 retval = fuse_update_attributes(inode, NULL, file, NULL);
2337                 if (!retval)
2338                         retval = generic_file_llseek(file, offset, whence);
2339                 inode_unlock(inode);
2340                 break;
2341         case SEEK_HOLE:
2342         case SEEK_DATA:
2343                 inode_lock(inode);
2344                 retval = fuse_lseek(file, offset, whence);
2345                 inode_unlock(inode);
2346                 break;
2347         default:
2348                 retval = -EINVAL;
2349         }
2350
2351         return retval;
2352 }
2353
2354 /*
2355  * CUSE servers compiled on 32bit broke on 64bit kernels because the
2356  * ABI was defined to be 'struct iovec' which is different on 32bit
2357  * and 64bit.  Fortunately we can determine which structure the server
2358  * used from the size of the reply.
2359  */
2360 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
2361                                      size_t transferred, unsigned count,
2362                                      bool is_compat)
2363 {
2364 #ifdef CONFIG_COMPAT
2365         if (count * sizeof(struct compat_iovec) == transferred) {
2366                 struct compat_iovec *ciov = src;
2367                 unsigned i;
2368
2369                 /*
2370                  * With this interface a 32bit server cannot support
2371                  * non-compat (i.e. ones coming from 64bit apps) ioctl
2372                  * requests
2373                  */
2374                 if (!is_compat)
2375                         return -EINVAL;
2376
2377                 for (i = 0; i < count; i++) {
2378                         dst[i].iov_base = compat_ptr(ciov[i].iov_base);
2379                         dst[i].iov_len = ciov[i].iov_len;
2380                 }
2381                 return 0;
2382         }
2383 #endif
2384
2385         if (count * sizeof(struct iovec) != transferred)
2386                 return -EIO;
2387
2388         memcpy(dst, src, transferred);
2389         return 0;
2390 }
2391
2392 /* Make sure iov_length() won't overflow */
2393 static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
2394 {
2395         size_t n;
2396         u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
2397
2398         for (n = 0; n < count; n++, iov++) {
2399                 if (iov->iov_len > (size_t) max)
2400                         return -ENOMEM;
2401                 max -= iov->iov_len;
2402         }
2403         return 0;
2404 }
2405
2406 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
2407                                  void *src, size_t transferred, unsigned count,
2408                                  bool is_compat)
2409 {
2410         unsigned i;
2411         struct fuse_ioctl_iovec *fiov = src;
2412
2413         if (fc->minor < 16) {
2414                 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
2415                                                  count, is_compat);
2416         }
2417
2418         if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
2419                 return -EIO;
2420
2421         for (i = 0; i < count; i++) {
2422                 /* Did the server supply an inappropriate value? */
2423                 if (fiov[i].base != (unsigned long) fiov[i].base ||
2424                     fiov[i].len != (unsigned long) fiov[i].len)
2425                         return -EIO;
2426
2427                 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
2428                 dst[i].iov_len = (size_t) fiov[i].len;
2429
2430 #ifdef CONFIG_COMPAT
2431                 if (is_compat &&
2432                     (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
2433                      (compat_size_t) dst[i].iov_len != fiov[i].len))
2434                         return -EIO;
2435 #endif
2436         }
2437
2438         return 0;
2439 }
2440
2441
2442 /*
2443  * For ioctls, there is no generic way to determine how much memory
2444  * needs to be read and/or written.  Furthermore, ioctls are allowed
2445  * to dereference the passed pointer, so the parameter requires deep
2446  * copying but FUSE has no idea whatsoever about what to copy in or
2447  * out.
2448  *
2449  * This is solved by allowing FUSE server to retry ioctl with
2450  * necessary in/out iovecs.  Let's assume the ioctl implementation
2451  * needs to read in the following structure.
2452  *
2453  * struct a {
2454  *      char    *buf;
2455  *      size_t  buflen;
2456  * }
2457  *
2458  * On the first callout to FUSE server, inarg->in_size and
2459  * inarg->out_size will be NULL; then, the server completes the ioctl
2460  * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
2461  * the actual iov array to
2462  *
2463  * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a) } }
2464  *
2465  * which tells FUSE to copy in the requested area and retry the ioctl.
2466  * On the second round, the server has access to the structure and
2467  * from that it can tell what to look for next, so on the invocation,
2468  * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
2469  *
2470  * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a)     },
2471  *   { .iov_base = a.buf,       .iov_len = a.buflen             } }
2472  *
2473  * FUSE will copy both struct a and the pointed buffer from the
2474  * process doing the ioctl and retry ioctl with both struct a and the
2475  * buffer.
2476  *
2477  * This time, FUSE server has everything it needs and completes ioctl
2478  * without FUSE_IOCTL_RETRY which finishes the ioctl call.
2479  *
2480  * Copying data out works the same way.
2481  *
2482  * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
2483  * automatically initializes in and out iovs by decoding @cmd with
2484  * _IOC_* macros and the server is not allowed to request RETRY.  This
2485  * limits ioctl data transfers to well-formed ioctls and is the forced
2486  * behavior for all FUSE servers.
2487  */
2488 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
2489                    unsigned int flags)
2490 {
2491         struct fuse_file *ff = file->private_data;
2492         struct fuse_conn *fc = ff->fc;
2493         struct fuse_ioctl_in inarg = {
2494                 .fh = ff->fh,
2495                 .cmd = cmd,
2496                 .arg = arg,
2497                 .flags = flags
2498         };
2499         struct fuse_ioctl_out outarg;
2500         struct fuse_req *req = NULL;
2501         struct page **pages = NULL;
2502         struct iovec *iov_page = NULL;
2503         struct iovec *in_iov = NULL, *out_iov = NULL;
2504         unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
2505         size_t in_size, out_size, transferred, c;
2506         int err, i;
2507         struct iov_iter ii;
2508
2509 #if BITS_PER_LONG == 32
2510         inarg.flags |= FUSE_IOCTL_32BIT;
2511 #else
2512         if (flags & FUSE_IOCTL_COMPAT)
2513                 inarg.flags |= FUSE_IOCTL_32BIT;
2514 #endif
2515
2516         /* assume all the iovs returned by client always fits in a page */
2517         BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
2518
2519         err = -ENOMEM;
2520         pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
2521         iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
2522         if (!pages || !iov_page)
2523                 goto out;
2524
2525         /*
2526          * If restricted, initialize IO parameters as encoded in @cmd.
2527          * RETRY from server is not allowed.
2528          */
2529         if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
2530                 struct iovec *iov = iov_page;
2531
2532                 iov->iov_base = (void __user *)arg;
2533
2534                 switch (cmd) {
2535                 case FS_IOC_GETFLAGS:
2536                 case FS_IOC_SETFLAGS:
2537                         iov->iov_len = sizeof(int);
2538                         break;
2539                 default:
2540                         iov->iov_len = _IOC_SIZE(cmd);
2541                         break;
2542                 }
2543
2544                 if (_IOC_DIR(cmd) & _IOC_WRITE) {
2545                         in_iov = iov;
2546                         in_iovs = 1;
2547                 }
2548
2549                 if (_IOC_DIR(cmd) & _IOC_READ) {
2550                         out_iov = iov;
2551                         out_iovs = 1;
2552                 }
2553         }
2554
2555  retry:
2556         inarg.in_size = in_size = iov_length(in_iov, in_iovs);
2557         inarg.out_size = out_size = iov_length(out_iov, out_iovs);
2558
2559         /*
2560          * Out data can be used either for actual out data or iovs,
2561          * make sure there always is at least one page.
2562          */
2563         out_size = max_t(size_t, out_size, PAGE_SIZE);
2564         max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
2565
2566         /* make sure there are enough buffer pages and init request with them */
2567         err = -ENOMEM;
2568         if (max_pages > FUSE_MAX_PAGES_PER_REQ)
2569                 goto out;
2570         while (num_pages < max_pages) {
2571                 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
2572                 if (!pages[num_pages])
2573                         goto out;
2574                 num_pages++;
2575         }
2576
2577         req = fuse_get_req(fc, num_pages);
2578         if (IS_ERR(req)) {
2579                 err = PTR_ERR(req);
2580                 req = NULL;
2581                 goto out;
2582         }
2583         memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
2584         req->num_pages = num_pages;
2585         fuse_page_descs_length_init(req, 0, req->num_pages);
2586
2587         /* okay, let's send it to the client */
2588         req->in.h.opcode = FUSE_IOCTL;
2589         req->in.h.nodeid = ff->nodeid;
2590         req->in.numargs = 1;
2591         req->in.args[0].size = sizeof(inarg);
2592         req->in.args[0].value = &inarg;
2593         if (in_size) {
2594                 req->in.numargs++;
2595                 req->in.args[1].size = in_size;
2596                 req->in.argpages = 1;
2597
2598                 err = -EFAULT;
2599                 iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size);
2600                 for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
2601                         c = copy_page_from_iter(pages[i], 0, PAGE_SIZE, &ii);
2602                         if (c != PAGE_SIZE && iov_iter_count(&ii))
2603                                 goto out;
2604                 }
2605         }
2606
2607         req->out.numargs = 2;
2608         req->out.args[0].size = sizeof(outarg);
2609         req->out.args[0].value = &outarg;
2610         req->out.args[1].size = out_size;
2611         req->out.argpages = 1;
2612         req->out.argvar = 1;
2613
2614         fuse_request_send(fc, req);
2615         err = req->out.h.error;
2616         transferred = req->out.args[1].size;
2617         fuse_put_request(fc, req);
2618         req = NULL;
2619         if (err)
2620                 goto out;
2621
2622         /* did it ask for retry? */
2623         if (outarg.flags & FUSE_IOCTL_RETRY) {
2624                 void *vaddr;
2625
2626                 /* no retry if in restricted mode */
2627                 err = -EIO;
2628                 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
2629                         goto out;
2630
2631                 in_iovs = outarg.in_iovs;
2632                 out_iovs = outarg.out_iovs;
2633
2634                 /*
2635                  * Make sure things are in boundary, separate checks
2636                  * are to protect against overflow.
2637                  */
2638                 err = -ENOMEM;
2639                 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
2640                     out_iovs > FUSE_IOCTL_MAX_IOV ||
2641                     in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
2642                         goto out;
2643
2644                 vaddr = kmap_atomic(pages[0]);
2645                 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2646                                             transferred, in_iovs + out_iovs,
2647                                             (flags & FUSE_IOCTL_COMPAT) != 0);
2648                 kunmap_atomic(vaddr);
2649                 if (err)
2650                         goto out;
2651
2652                 in_iov = iov_page;
2653                 out_iov = in_iov + in_iovs;
2654
2655                 err = fuse_verify_ioctl_iov(in_iov, in_iovs);
2656                 if (err)
2657                         goto out;
2658
2659                 err = fuse_verify_ioctl_iov(out_iov, out_iovs);
2660                 if (err)
2661                         goto out;
2662
2663                 goto retry;
2664         }
2665
2666         err = -EIO;
2667         if (transferred > inarg.out_size)
2668                 goto out;
2669
2670         err = -EFAULT;
2671         iov_iter_init(&ii, READ, out_iov, out_iovs, transferred);
2672         for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
2673                 c = copy_page_to_iter(pages[i], 0, PAGE_SIZE, &ii);
2674                 if (c != PAGE_SIZE && iov_iter_count(&ii))
2675                         goto out;
2676         }
2677         err = 0;
2678  out:
2679         if (req)
2680                 fuse_put_request(fc, req);
2681         free_page((unsigned long) iov_page);
2682         while (num_pages)
2683                 __free_page(pages[--num_pages]);
2684         kfree(pages);
2685
2686         return err ? err : outarg.result;
2687 }
2688 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2689
2690 long fuse_ioctl_common(struct file *file, unsigned int cmd,
2691                        unsigned long arg, unsigned int flags)
2692 {
2693         struct inode *inode = file_inode(file);
2694         struct fuse_conn *fc = get_fuse_conn(inode);
2695
2696         if (!fuse_allow_current_process(fc))
2697                 return -EACCES;
2698
2699         if (fuse_is_bad(inode))
2700                 return -EIO;
2701
2702         return fuse_do_ioctl(file, cmd, arg, flags);
2703 }
2704
2705 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2706                             unsigned long arg)
2707 {
2708         return fuse_ioctl_common(file, cmd, arg, 0);
2709 }
2710
2711 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2712                                    unsigned long arg)
2713 {
2714         return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2715 }
2716
2717 /*
2718  * All files which have been polled are linked to RB tree
2719  * fuse_conn->polled_files which is indexed by kh.  Walk the tree and
2720  * find the matching one.
2721  */
2722 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2723                                               struct rb_node **parent_out)
2724 {
2725         struct rb_node **link = &fc->polled_files.rb_node;
2726         struct rb_node *last = NULL;
2727
2728         while (*link) {
2729                 struct fuse_file *ff;
2730
2731                 last = *link;
2732                 ff = rb_entry(last, struct fuse_file, polled_node);
2733
2734                 if (kh < ff->kh)
2735                         link = &last->rb_left;
2736                 else if (kh > ff->kh)
2737                         link = &last->rb_right;
2738                 else
2739                         return link;
2740         }
2741
2742         if (parent_out)
2743                 *parent_out = last;
2744         return link;
2745 }
2746
2747 /*
2748  * The file is about to be polled.  Make sure it's on the polled_files
2749  * RB tree.  Note that files once added to the polled_files tree are
2750  * not removed before the file is released.  This is because a file
2751  * polled once is likely to be polled again.
2752  */
2753 static void fuse_register_polled_file(struct fuse_conn *fc,
2754                                       struct fuse_file *ff)
2755 {
2756         spin_lock(&fc->lock);
2757         if (RB_EMPTY_NODE(&ff->polled_node)) {
2758                 struct rb_node **link, *uninitialized_var(parent);
2759
2760                 link = fuse_find_polled_node(fc, ff->kh, &parent);
2761                 BUG_ON(*link);
2762                 rb_link_node(&ff->polled_node, parent, link);
2763                 rb_insert_color(&ff->polled_node, &fc->polled_files);
2764         }
2765         spin_unlock(&fc->lock);
2766 }
2767
2768 unsigned fuse_file_poll(struct file *file, poll_table *wait)
2769 {
2770         struct fuse_file *ff = file->private_data;
2771         struct fuse_conn *fc = ff->fc;
2772         struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2773         struct fuse_poll_out outarg;
2774         FUSE_ARGS(args);
2775         int err;
2776
2777         if (fc->no_poll)
2778                 return DEFAULT_POLLMASK;
2779
2780         poll_wait(file, &ff->poll_wait, wait);
2781         inarg.events = (__u32)poll_requested_events(wait);
2782
2783         /*
2784          * Ask for notification iff there's someone waiting for it.
2785          * The client may ignore the flag and always notify.
2786          */
2787         if (waitqueue_active(&ff->poll_wait)) {
2788                 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2789                 fuse_register_polled_file(fc, ff);
2790         }
2791
2792         args.in.h.opcode = FUSE_POLL;
2793         args.in.h.nodeid = ff->nodeid;
2794         args.in.numargs = 1;
2795         args.in.args[0].size = sizeof(inarg);
2796         args.in.args[0].value = &inarg;
2797         args.out.numargs = 1;
2798         args.out.args[0].size = sizeof(outarg);
2799         args.out.args[0].value = &outarg;
2800         err = fuse_simple_request(fc, &args);
2801
2802         if (!err)
2803                 return outarg.revents;
2804         if (err == -ENOSYS) {
2805                 fc->no_poll = 1;
2806                 return DEFAULT_POLLMASK;
2807         }
2808         return POLLERR;
2809 }
2810 EXPORT_SYMBOL_GPL(fuse_file_poll);
2811
2812 /*
2813  * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2814  * wakes up the poll waiters.
2815  */
2816 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2817                             struct fuse_notify_poll_wakeup_out *outarg)
2818 {
2819         u64 kh = outarg->kh;
2820         struct rb_node **link;
2821
2822         spin_lock(&fc->lock);
2823
2824         link = fuse_find_polled_node(fc, kh, NULL);
2825         if (*link) {
2826                 struct fuse_file *ff;
2827
2828                 ff = rb_entry(*link, struct fuse_file, polled_node);
2829                 wake_up_interruptible_sync(&ff->poll_wait);
2830         }
2831
2832         spin_unlock(&fc->lock);
2833         return 0;
2834 }
2835
2836 static void fuse_do_truncate(struct file *file)
2837 {
2838         struct inode *inode = file->f_mapping->host;
2839         struct iattr attr;
2840
2841         attr.ia_valid = ATTR_SIZE;
2842         attr.ia_size = i_size_read(inode);
2843
2844         attr.ia_file = file;
2845         attr.ia_valid |= ATTR_FILE;
2846
2847         fuse_do_setattr(file_dentry(file), &attr, file);
2848 }
2849
2850 static inline loff_t fuse_round_up(loff_t off)
2851 {
2852         return round_up(off, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
2853 }
2854
2855 static ssize_t
2856 fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2857 {
2858         DECLARE_COMPLETION_ONSTACK(wait);
2859         ssize_t ret = 0;
2860         struct file *file = iocb->ki_filp;
2861         struct fuse_file *ff = file->private_data;
2862         bool async_dio = ff->fc->async_dio;
2863         loff_t pos = 0;
2864         struct inode *inode;
2865         loff_t i_size;
2866         size_t count = iov_iter_count(iter);
2867         loff_t offset = iocb->ki_pos;
2868         struct fuse_io_priv *io;
2869
2870         pos = offset;
2871         inode = file->f_mapping->host;
2872         i_size = i_size_read(inode);
2873
2874         if ((iov_iter_rw(iter) == READ) && (offset > i_size))
2875                 return 0;
2876
2877         /* optimization for short read */
2878         if (async_dio && iov_iter_rw(iter) != WRITE && offset + count > i_size) {
2879                 if (offset >= i_size)
2880                         return 0;
2881                 iov_iter_truncate(iter, fuse_round_up(i_size - offset));
2882                 count = iov_iter_count(iter);
2883         }
2884
2885         io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2886         if (!io)
2887                 return -ENOMEM;
2888         spin_lock_init(&io->lock);
2889         kref_init(&io->refcnt);
2890         io->reqs = 1;
2891         io->bytes = -1;
2892         io->size = 0;
2893         io->offset = offset;
2894         io->write = (iov_iter_rw(iter) == WRITE);
2895         io->err = 0;
2896         io->file = file;
2897         /*
2898          * By default, we want to optimize all I/Os with async request
2899          * submission to the client filesystem if supported.
2900          */
2901         io->async = async_dio;
2902         io->iocb = iocb;
2903         io->blocking = is_sync_kiocb(iocb);
2904
2905         /*
2906          * We cannot asynchronously extend the size of a file.
2907          * In such case the aio will behave exactly like sync io.
2908          */
2909         if ((offset + count > i_size) && iov_iter_rw(iter) == WRITE)
2910                 io->blocking = true;
2911
2912         if (io->async && io->blocking) {
2913                 /*
2914                  * Additional reference to keep io around after
2915                  * calling fuse_aio_complete()
2916                  */
2917                 kref_get(&io->refcnt);
2918                 io->done = &wait;
2919         }
2920
2921         if (iov_iter_rw(iter) == WRITE) {
2922                 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
2923                 fuse_invalidate_attr(inode);
2924         } else {
2925                 ret = __fuse_direct_read(io, iter, &pos);
2926         }
2927
2928         if (io->async) {
2929                 bool blocking = io->blocking;
2930
2931                 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2932
2933                 /* we have a non-extending, async request, so return */
2934                 if (!blocking)
2935                         return -EIOCBQUEUED;
2936
2937                 wait_for_completion(&wait);
2938                 ret = fuse_get_res_by_io(io);
2939         }
2940
2941         kref_put(&io->refcnt, fuse_io_release);
2942
2943         if (iov_iter_rw(iter) == WRITE) {
2944                 if (ret > 0)
2945                         fuse_write_update_size(inode, pos);
2946                 else if (ret < 0 && offset + count > i_size)
2947                         fuse_do_truncate(file);
2948         }
2949
2950         return ret;
2951 }
2952
2953 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2954                                 loff_t length)
2955 {
2956         struct fuse_file *ff = file->private_data;
2957         struct inode *inode = file_inode(file);
2958         struct fuse_inode *fi = get_fuse_inode(inode);
2959         struct fuse_conn *fc = ff->fc;
2960         FUSE_ARGS(args);
2961         struct fuse_fallocate_in inarg = {
2962                 .fh = ff->fh,
2963                 .offset = offset,
2964                 .length = length,
2965                 .mode = mode
2966         };
2967         int err;
2968         bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
2969                            (mode & FALLOC_FL_PUNCH_HOLE);
2970
2971         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2972                 return -EOPNOTSUPP;
2973
2974         if (fc->no_fallocate)
2975                 return -EOPNOTSUPP;
2976
2977         if (lock_inode) {
2978                 inode_lock(inode);
2979                 if (mode & FALLOC_FL_PUNCH_HOLE) {
2980                         loff_t endbyte = offset + length - 1;
2981                         err = filemap_write_and_wait_range(inode->i_mapping,
2982                                                            offset, endbyte);
2983                         if (err)
2984                                 goto out;
2985
2986                         fuse_sync_writes(inode);
2987                 }
2988         }
2989
2990         if (!(mode & FALLOC_FL_KEEP_SIZE) &&
2991             offset + length > i_size_read(inode)) {
2992                 err = inode_newsize_ok(inode, offset + length);
2993                 if (err)
2994                         goto out;
2995         }
2996
2997         if (!(mode & FALLOC_FL_KEEP_SIZE))
2998                 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2999
3000         args.in.h.opcode = FUSE_FALLOCATE;
3001         args.in.h.nodeid = ff->nodeid;
3002         args.in.numargs = 1;
3003         args.in.args[0].size = sizeof(inarg);
3004         args.in.args[0].value = &inarg;
3005         err = fuse_simple_request(fc, &args);
3006         if (err == -ENOSYS) {
3007                 fc->no_fallocate = 1;
3008                 err = -EOPNOTSUPP;
3009         }
3010         if (err)
3011                 goto out;
3012
3013         /* we could have extended the file */
3014         if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3015                 bool changed = fuse_write_update_size(inode, offset + length);
3016
3017                 if (changed && fc->writeback_cache)
3018                         file_update_time(file);
3019         }
3020
3021         if (mode & FALLOC_FL_PUNCH_HOLE)
3022                 truncate_pagecache_range(inode, offset, offset + length - 1);
3023
3024         fuse_invalidate_attr(inode);
3025
3026 out:
3027         if (!(mode & FALLOC_FL_KEEP_SIZE))
3028                 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3029
3030         if (lock_inode)
3031                 inode_unlock(inode);
3032
3033         return err;
3034 }
3035
3036 static const struct file_operations fuse_file_operations = {
3037         .llseek         = fuse_file_llseek,
3038         .read_iter      = fuse_file_read_iter,
3039         .write_iter     = fuse_file_write_iter,
3040         .mmap           = fuse_file_mmap,
3041         .open           = fuse_open,
3042         .flush          = fuse_flush,
3043         .release        = fuse_release,
3044         .fsync          = fuse_fsync,
3045         .lock           = fuse_file_lock,
3046         .flock          = fuse_file_flock,
3047         .splice_read    = generic_file_splice_read,
3048         .unlocked_ioctl = fuse_file_ioctl,
3049         .compat_ioctl   = fuse_file_compat_ioctl,
3050         .poll           = fuse_file_poll,
3051         .fallocate      = fuse_file_fallocate,
3052 };
3053
3054 static const struct file_operations fuse_direct_io_file_operations = {
3055         .llseek         = fuse_file_llseek,
3056         .read_iter      = fuse_direct_read_iter,
3057         .write_iter     = fuse_direct_write_iter,
3058         .mmap           = fuse_direct_mmap,
3059         .open           = fuse_open,
3060         .flush          = fuse_flush,
3061         .release        = fuse_release,
3062         .fsync          = fuse_fsync,
3063         .lock           = fuse_file_lock,
3064         .flock          = fuse_file_flock,
3065         .unlocked_ioctl = fuse_file_ioctl,
3066         .compat_ioctl   = fuse_file_compat_ioctl,
3067         .poll           = fuse_file_poll,
3068         .fallocate      = fuse_file_fallocate,
3069         /* no splice_read */
3070 };
3071
3072 static const struct address_space_operations fuse_file_aops  = {
3073         .readpage       = fuse_readpage,
3074         .writepage      = fuse_writepage,
3075         .writepages     = fuse_writepages,
3076         .launder_page   = fuse_launder_page,
3077         .readpages      = fuse_readpages,
3078         .set_page_dirty = __set_page_dirty_nobuffers,
3079         .bmap           = fuse_bmap,
3080         .direct_IO      = fuse_direct_IO,
3081         .write_begin    = fuse_write_begin,
3082         .write_end      = fuse_write_end,
3083 };
3084
3085 void fuse_init_file_inode(struct inode *inode)
3086 {
3087         inode->i_fop = &fuse_file_operations;
3088         inode->i_data.a_ops = &fuse_file_aops;
3089 }