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/aio.h>
  19 #include <linux/falloc.h>
  20
  21 static const struct file_operations fuse_direct_io_file_operations;
  22
  23 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
  24                           int opcode, struct fuse_open_out *outargp)
  25 {
  26         struct fuse_open_in inarg;
  27         struct fuse_req *req;
  28         int err;
  29
  30         req = fuse_get_req_nopages(fc);
  31         if (IS_ERR(req))
  32                 return PTR_ERR(req);
  33
  34         memset(&inarg, 0, sizeof(inarg));
  35         inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
  36         if (!fc->atomic_o_trunc)
  37                 inarg.flags &= ~O_TRUNC;
  38         req->in.h.opcode = opcode;
  39         req->in.h.nodeid = nodeid;
  40         req->in.numargs = 1;
  41         req->in.args[0].size = sizeof(inarg);
  42         req->in.args[0].value = &inarg;
  43         req->out.numargs = 1;
  44         req->out.args[0].size = sizeof(*outargp);
  45         req->out.args[0].value = outargp;
  46         fuse_request_send(fc, req);
  47         err = req->out.h.error;
  48         fuse_put_request(fc, req);
  49
  50         return err;
  51 }
  52
  53 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
  54 {
  55         struct fuse_file *ff;
  56
  57         ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
  58         if (unlikely(!ff))
  59                 return NULL;
  60
  61         ff->fc = fc;
  62         ff->reserved_req = fuse_request_alloc(0);
  63         if (unlikely(!ff->reserved_req)) {
  64                 kfree(ff);
  65                 return NULL;
  66         }
  67
  68         INIT_LIST_HEAD(&ff->write_entry);
  69         atomic_set(&ff->count, 0);
  70         RB_CLEAR_NODE(&ff->polled_node);
  71         init_waitqueue_head(&ff->poll_wait);
  72
  73         spin_lock(&fc->lock);
  74         ff->kh = ++fc->khctr;
  75         spin_unlock(&fc->lock);
  76
  77         return ff;
  78 }
  79
  80 void fuse_file_free(struct fuse_file *ff)
  81 {
  82         fuse_request_free(ff->reserved_req);
  83         kfree(ff);
  84 }
  85
  86 struct fuse_file *fuse_file_get(struct fuse_file *ff)
  87 {
  88         atomic_inc(&ff->count);
  89         return ff;
  90 }
  91
  92 static void fuse_release_async(struct work_struct *work)
  93 {
  94         struct fuse_req *req;
  95         struct fuse_conn *fc;
  96         struct path path;
  97
  98         req = container_of(work, struct fuse_req, misc.release.work);
  99         path = req->misc.release.path;
 100         fc = get_fuse_conn(path.dentry->d_inode);
 101
 102         fuse_put_request(fc, req);
 103         path_put(&path);
 104 }
 105
 106 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
 107 {
 108         if (fc->destroy_req) {
 109                 /*
 110                  * If this is a fuseblk mount, then it's possible that
 111                  * releasing the path will result in releasing the
 112                  * super block and sending the DESTROY request.  If
 113                  * the server is single threaded, this would hang.
 114                  * For this reason do the path_put() in a separate
 115                  * thread.
 116                  */
 117                 atomic_inc(&req->count);
 118                 INIT_WORK(&req->misc.release.work, fuse_release_async);
 119                 schedule_work(&req->misc.release.work);
 120         } else {
 121                 path_put(&req->misc.release.path);
 122         }
 123 }
 124
 125 static void fuse_file_put(struct fuse_file *ff, bool sync)
 126 {
 127         if (atomic_dec_and_test(&ff->count)) {
 128                 struct fuse_req *req = ff->reserved_req;
 129
 130                 if (sync) {
 131                         req->background = 0;
 132                         fuse_request_send(ff->fc, req);
 133                         path_put(&req->misc.release.path);
 134                         fuse_put_request(ff->fc, req);
 135                 } else {
 136                         req->end = fuse_release_end;
 137                         req->background = 1;
 138                         fuse_request_send_background(ff->fc, req);
 139                 }
 140                 kfree(ff);
 141         }
 142 }
 143
 144 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
 145                  bool isdir)
 146 {
 147         struct fuse_open_out outarg;
 148         struct fuse_file *ff;
 149         int err;
 150         int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
 151
 152         ff = fuse_file_alloc(fc);
 153         if (!ff)
 154                 return -ENOMEM;
 155
 156         err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
 157         if (err) {
 158                 fuse_file_free(ff);
 159                 return err;
 160         }
 161
 162         if (isdir)
 163                 outarg.open_flags &= ~FOPEN_DIRECT_IO;
 164
 165         ff->fh = outarg.fh;
 166         ff->nodeid = nodeid;
 167         ff->open_flags = outarg.open_flags;
 168         file->private_data = fuse_file_get(ff);
 169
 170         return 0;
 171 }
 172 EXPORT_SYMBOL_GPL(fuse_do_open);
 173
 174 void fuse_finish_open(struct inode *inode, struct file *file)
 175 {
 176         struct fuse_file *ff = file->private_data;
 177         struct fuse_conn *fc = get_fuse_conn(inode);
 178
 179         if (ff->open_flags & FOPEN_DIRECT_IO)
 180                 file->f_op = &fuse_direct_io_file_operations;
 181         if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 182                 invalidate_inode_pages2(inode->i_mapping);
 183         if (ff->open_flags & FOPEN_NONSEEKABLE)
 184                 nonseekable_open(inode, file);
 185         if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
 186                 struct fuse_inode *fi = get_fuse_inode(inode);
 187
 188                 spin_lock(&fc->lock);
 189                 fi->attr_version = ++fc->attr_version;
 190                 i_size_write(inode, 0);
 191                 spin_unlock(&fc->lock);
 192                 fuse_invalidate_attr(inode);
 193         }
 194 }
 195
 196 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
 197 {
 198         struct fuse_conn *fc = get_fuse_conn(inode);
 199         int err;
 200
 201         err = generic_file_open(inode, file);
 202         if (err)
 203                 return err;
 204
 205         err = fuse_do_open(fc, get_node_id(inode), file, isdir);
 206         if (err)
 207                 return err;
 208
 209         fuse_finish_open(inode, file);
 210
 211         return 0;
 212 }
 213
 214 static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
 215 {
 216         struct fuse_conn *fc = ff->fc;
 217         struct fuse_req *req = ff->reserved_req;
 218         struct fuse_release_in *inarg = &req->misc.release.in;
 219
 220         spin_lock(&fc->lock);
 221         list_del(&ff->write_entry);
 222         if (!RB_EMPTY_NODE(&ff->polled_node))
 223                 rb_erase(&ff->polled_node, &fc->polled_files);
 224         spin_unlock(&fc->lock);
 225
 226         wake_up_interruptible_all(&ff->poll_wait);
 227
 228         inarg->fh = ff->fh;
 229         inarg->flags = flags;
 230         req->in.h.opcode = opcode;
 231         req->in.h.nodeid = ff->nodeid;
 232         req->in.numargs = 1;
 233         req->in.args[0].size = sizeof(struct fuse_release_in);
 234         req->in.args[0].value = inarg;
 235 }
 236
 237 void fuse_release_common(struct file *file, int opcode)
 238 {
 239         struct fuse_file *ff;
 240         struct fuse_req *req;
 241
 242         ff = file->private_data;
 243         if (unlikely(!ff))
 244                 return;
 245
 246         req = ff->reserved_req;
 247         fuse_prepare_release(ff, file->f_flags, opcode);
 248
 249         if (ff->flock) {
 250                 struct fuse_release_in *inarg = &req->misc.release.in;
 251                 inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
 252                 inarg->lock_owner = fuse_lock_owner_id(ff->fc,
 253                                                        (fl_owner_t) file);
 254         }
 255         /* Hold vfsmount and dentry until release is finished */
 256         path_get(&file->f_path);
 257         req->misc.release.path = file->f_path;
 258
 259         /*
 260          * Normally this will send the RELEASE request, however if
 261          * some asynchronous READ or WRITE requests are outstanding,
 262          * the sending will be delayed.
 263          *
 264          * Make the release synchronous if this is a fuseblk mount,
 265          * synchronous RELEASE is allowed (and desirable) in this case
 266          * because the server can be trusted not to screw up.
 267          */
 268         fuse_file_put(ff, ff->fc->destroy_req != NULL);
 269 }
 270
 271 static int fuse_open(struct inode *inode, struct file *file)
 272 {
 273         return fuse_open_common(inode, file, false);
 274 }
 275
 276 static int fuse_release(struct inode *inode, struct file *file)
 277 {
 278         fuse_release_common(file, FUSE_RELEASE);
 279
 280         /* return value is ignored by VFS */
 281         return 0;
 282 }
 283
 284 void fuse_sync_release(struct fuse_file *ff, int flags)
 285 {
 286         WARN_ON(atomic_read(&ff->count) > 1);
 287         fuse_prepare_release(ff, flags, FUSE_RELEASE);
 288         ff->reserved_req->force = 1;
 289         ff->reserved_req->background = 0;
 290         fuse_request_send(ff->fc, ff->reserved_req);
 291         fuse_put_request(ff->fc, ff->reserved_req);
 292         kfree(ff);
 293 }
 294 EXPORT_SYMBOL_GPL(fuse_sync_release);
 295
 296 /*
 297  * Scramble the ID space with XTEA, so that the value of the files_struct
 298  * pointer is not exposed to userspace.
 299  */
 300 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 301 {
 302         u32 *k = fc->scramble_key;
 303         u64 v = (unsigned long) id;
 304         u32 v0 = v;
 305         u32 v1 = v >> 32;
 306         u32 sum = 0;
 307         int i;
 308
 309         for (i = 0; i < 32; i++) {
 310                 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
 311                 sum += 0x9E3779B9;
 312                 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
 313         }
 314
 315         return (u64) v0 + ((u64) v1 << 32);
 316 }
 317
 318 /*
 319  * Check if page is under writeback
 320  *
 321  * This is currently done by walking the list of writepage requests
 322  * for the inode, which can be pretty inefficient.
 323  */
 324 static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
 325 {
 326         struct fuse_conn *fc = get_fuse_conn(inode);
 327         struct fuse_inode *fi = get_fuse_inode(inode);
 328         struct fuse_req *req;
 329         bool found = false;
 330
 331         spin_lock(&fc->lock);
 332         list_for_each_entry(req, &fi->writepages, writepages_entry) {
 333                 pgoff_t curr_index;
 334
 335                 BUG_ON(req->inode != inode);
 336                 curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
 337                 if (curr_index == index) {
 338                         found = true;
 339                         break;
 340                 }
 341         }
 342         spin_unlock(&fc->lock);
 343
 344         return found;
 345 }
 346
 347 /*
 348  * Wait for page writeback to be completed.
 349  *
 350  * Since fuse doesn't rely on the VM writeback tracking, this has to
 351  * use some other means.
 352  */
 353 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
 354 {
 355         struct fuse_inode *fi = get_fuse_inode(inode);
 356
 357         wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
 358         return 0;
 359 }
 360
 361 static int fuse_flush(struct file *file, fl_owner_t id)
 362 {
 363         struct inode *inode = file_inode(file);
 364         struct fuse_conn *fc = get_fuse_conn(inode);
 365         struct fuse_file *ff = file->private_data;
 366         struct fuse_req *req;
 367         struct fuse_flush_in inarg;
 368         int err;
 369
 370         if (is_bad_inode(inode))
 371                 return -EIO;
 372
 373         if (fc->no_flush)
 374                 return 0;
 375
 376         req = fuse_get_req_nofail_nopages(fc, file);
 377         memset(&inarg, 0, sizeof(inarg));
 378         inarg.fh = ff->fh;
 379         inarg.lock_owner = fuse_lock_owner_id(fc, id);
 380         req->in.h.opcode = FUSE_FLUSH;
 381         req->in.h.nodeid = get_node_id(inode);
 382         req->in.numargs = 1;
 383         req->in.args[0].size = sizeof(inarg);
 384         req->in.args[0].value = &inarg;
 385         req->force = 1;
 386         fuse_request_send(fc, req);
 387         err = req->out.h.error;
 388         fuse_put_request(fc, req);
 389         if (err == -ENOSYS) {
 390                 fc->no_flush = 1;
 391                 err = 0;
 392         }
 393         return err;
 394 }
 395
 396 /*
 397  * Wait for all pending writepages on the inode to finish.
 398  *
 399  * This is currently done by blocking further writes with FUSE_NOWRITE
 400  * and waiting for all sent writes to complete.
 401  *
 402  * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
 403  * could conflict with truncation.
 404  */
 405 static void fuse_sync_writes(struct inode *inode)
 406 {
 407         fuse_set_nowrite(inode);
 408         fuse_release_nowrite(inode);
 409 }
 410
 411 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
 412                       int datasync, int isdir)
 413 {
 414         struct inode *inode = file->f_mapping->host;
 415         struct fuse_conn *fc = get_fuse_conn(inode);
 416         struct fuse_file *ff = file->private_data;
 417         struct fuse_req *req;
 418         struct fuse_fsync_in inarg;
 419         int err;
 420
 421         if (is_bad_inode(inode))
 422                 return -EIO;
 423
 424         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
 425         if (err)
 426                 return err;
 427
 428         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 429                 return 0;
 430
 431         mutex_lock(&inode->i_mutex);
 432
 433         /*
 434          * Start writeback against all dirty pages of the inode, then
 435          * wait for all outstanding writes, before sending the FSYNC
 436          * request.
 437          */
 438         err = write_inode_now(inode, 0);
 439         if (err)
 440                 goto out;
 441
 442         fuse_sync_writes(inode);
 443
 444         req = fuse_get_req_nopages(fc);
 445         if (IS_ERR(req)) {
 446                 err = PTR_ERR(req);
 447                 goto out;
 448         }
 449
 450         memset(&inarg, 0, sizeof(inarg));
 451         inarg.fh = ff->fh;
 452         inarg.fsync_flags = datasync ? 1 : 0;
 453         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 454         req->in.h.nodeid = get_node_id(inode);
 455         req->in.numargs = 1;
 456         req->in.args[0].size = sizeof(inarg);
 457         req->in.args[0].value = &inarg;
 458         fuse_request_send(fc, req);
 459         err = req->out.h.error;
 460         fuse_put_request(fc, req);
 461         if (err == -ENOSYS) {
 462                 if (isdir)
 463                         fc->no_fsyncdir = 1;
 464                 else
 465                         fc->no_fsync = 1;
 466                 err = 0;
 467         }
 468 out:
 469         mutex_unlock(&inode->i_mutex);
 470         return err;
 471 }
 472
 473 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
 474                       int datasync)
 475 {
 476         return fuse_fsync_common(file, start, end, datasync, 0);
 477 }
 478
 479 void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
 480                     size_t count, int opcode)
 481 {
 482         struct fuse_read_in *inarg = &req->misc.read.in;
 483         struct fuse_file *ff = file->private_data;
 484
 485         inarg->fh = ff->fh;
 486         inarg->offset = pos;
 487         inarg->size = count;
 488         inarg->flags = file->f_flags;
 489         req->in.h.opcode = opcode;
 490         req->in.h.nodeid = ff->nodeid;
 491         req->in.numargs = 1;
 492         req->in.args[0].size = sizeof(struct fuse_read_in);
 493         req->in.args[0].value = inarg;
 494         req->out.argvar = 1;
 495         req->out.numargs = 1;
 496         req->out.args[0].size = count;
 497 }
 498
 499 static void fuse_release_user_pages(struct fuse_req *req, int write)
 500 {
 501         unsigned i;
 502
 503         for (i = 0; i < req->num_pages; i++) {
 504                 struct page *page = req->pages[i];
 505                 if (write)
 506                         set_page_dirty_lock(page);
 507                 put_page(page);
 508         }
 509 }
 510
 511 /**
 512  * In case of short read, the caller sets 'pos' to the position of
 513  * actual end of fuse request in IO request. Otherwise, if bytes_requested
 514  * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
 515  *
 516  * An example:
 517  * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
 518  * both submitted asynchronously. The first of them was ACKed by userspace as
 519  * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
 520  * second request was ACKed as short, e.g. only 1K was read, resulting in
 521  * pos == 33K.
 522  *
 523  * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
 524  * will be equal to the length of the longest contiguous fragment of
 525  * transferred data starting from the beginning of IO request.
 526  */
 527 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
 528 {
 529         int left;
 530
 531         spin_lock(&io->lock);
 532         if (err)
 533                 io->err = io->err ? : err;
 534         else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
 535                 io->bytes = pos;
 536
 537         left = --io->reqs;
 538         spin_unlock(&io->lock);
 539
 540         if (!left) {
 541                 long res;
 542
 543                 if (io->err)
 544                         res = io->err;
 545                 else if (io->bytes >= 0 && io->write)
 546                         res = -EIO;
 547                 else {
 548                         res = io->bytes < 0 ? io->size : io->bytes;
 549
 550                         if (!is_sync_kiocb(io->iocb)) {
 551                                 struct path *path = &io->iocb->ki_filp->f_path;
 552                                 struct inode *inode = path->dentry->d_inode;
 553                                 struct fuse_conn *fc = get_fuse_conn(inode);
 554                                 struct fuse_inode *fi = get_fuse_inode(inode);
 555
 556                                 spin_lock(&fc->lock);
 557                                 fi->attr_version = ++fc->attr_version;
 558                                 spin_unlock(&fc->lock);
 559                         }
 560                 }
 561
 562                 aio_complete(io->iocb, res, 0);
 563                 kfree(io);
 564         }
 565 }
 566
 567 static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
 568 {
 569         struct fuse_io_priv *io = req->io;
 570         ssize_t pos = -1;
 571
 572         fuse_release_user_pages(req, !io->write);
 573
 574         if (io->write) {
 575                 if (req->misc.write.in.size != req->misc.write.out.size)
 576                         pos = req->misc.write.in.offset - io->offset +
 577                                 req->misc.write.out.size;
 578         } else {
 579                 if (req->misc.read.in.size != req->out.args[0].size)
 580                         pos = req->misc.read.in.offset - io->offset +
 581                                 req->out.args[0].size;
 582         }
 583
 584         fuse_aio_complete(io, req->out.h.error, pos);
 585 }
 586
 587 static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
 588                 size_t num_bytes, struct fuse_io_priv *io)
 589 {
 590         spin_lock(&io->lock);
 591         io->size += num_bytes;
 592         io->reqs++;
 593         spin_unlock(&io->lock);
 594
 595         req->io = io;
 596         req->end = fuse_aio_complete_req;
 597
 598         __fuse_get_request(req);
 599         fuse_request_send_background(fc, req);
 600
 601         return num_bytes;
 602 }
 603
 604 static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
 605                              loff_t pos, size_t count, fl_owner_t owner)
 606 {
 607         struct file *file = io->file;
 608         struct fuse_file *ff = file->private_data;
 609         struct fuse_conn *fc = ff->fc;
 610
 611         fuse_read_fill(req, file, pos, count, FUSE_READ);
 612         if (owner != NULL) {
 613                 struct fuse_read_in *inarg = &req->misc.read.in;
 614
 615                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
 616                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 617         }
 618
 619         if (io->async)
 620                 return fuse_async_req_send(fc, req, count, io);
 621
 622         fuse_request_send(fc, req);
 623         return req->out.args[0].size;
 624 }
 625
 626 static void fuse_read_update_size(struct inode *inode, loff_t size,
 627                                   u64 attr_ver)
 628 {
 629         struct fuse_conn *fc = get_fuse_conn(inode);
 630         struct fuse_inode *fi = get_fuse_inode(inode);
 631
 632         spin_lock(&fc->lock);
 633         if (attr_ver == fi->attr_version && size < inode->i_size) {
 634                 fi->attr_version = ++fc->attr_version;
 635                 i_size_write(inode, size);
 636         }
 637         spin_unlock(&fc->lock);
 638 }
 639
 640 static int fuse_readpage(struct file *file, struct page *page)
 641 {
 642         struct fuse_io_priv io = { .async = 0, .file = file };
 643         struct inode *inode = page->mapping->host;
 644         struct fuse_conn *fc = get_fuse_conn(inode);
 645         struct fuse_req *req;
 646         size_t num_read;
 647         loff_t pos = page_offset(page);
 648         size_t count = PAGE_CACHE_SIZE;
 649         u64 attr_ver;
 650         int err;
 651
 652         err = -EIO;
 653         if (is_bad_inode(inode))
 654                 goto out;
 655
 656         /*
 657          * Page writeback can extend beyond the lifetime of the
 658          * page-cache page, so make sure we read a properly synced
 659          * page.
 660          */
 661         fuse_wait_on_page_writeback(inode, page->index);
 662
 663         req = fuse_get_req(fc, 1);
 664         err = PTR_ERR(req);
 665         if (IS_ERR(req))
 666                 goto out;
 667
 668         attr_ver = fuse_get_attr_version(fc);
 669
 670         req->out.page_zeroing = 1;
 671         req->out.argpages = 1;
 672         req->num_pages = 1;
 673         req->pages[0] = page;
 674         req->page_descs[0].length = count;
 675         num_read = fuse_send_read(req, &io, pos, count, NULL);
 676         err = req->out.h.error;
 677         fuse_put_request(fc, req);
 678
 679         if (!err) {
 680                 /*
 681                  * Short read means EOF.  If file size is larger, truncate it
 682                  */
 683                 if (num_read < count)
 684                         fuse_read_update_size(inode, pos + num_read, attr_ver);
 685
 686                 SetPageUptodate(page);
 687         }
 688
 689         fuse_invalidate_attr(inode); /* atime changed */
 690  out:
 691         unlock_page(page);
 692         return err;
 693 }
 694
 695 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 696 {
 697         int i;
 698         size_t count = req->misc.read.in.size;
 699         size_t num_read = req->out.args[0].size;
 700         struct address_space *mapping = NULL;
 701
 702         for (i = 0; mapping == NULL && i < req->num_pages; i++)
 703                 mapping = req->pages[i]->mapping;
 704
 705         if (mapping) {
 706                 struct inode *inode = mapping->host;
 707
 708                 /*
 709                  * Short read means EOF. If file size is larger, truncate it
 710                  */
 711                 if (!req->out.h.error && num_read < count) {
 712                         loff_t pos;
 713
 714                         pos = page_offset(req->pages[0]) + num_read;
 715                         fuse_read_update_size(inode, pos,
 716                                               req->misc.read.attr_ver);
 717                 }
 718                 fuse_invalidate_attr(inode); /* atime changed */
 719         }
 720
 721         for (i = 0; i < req->num_pages; i++) {
 722                 struct page *page = req->pages[i];
 723                 if (!req->out.h.error)
 724                         SetPageUptodate(page);
 725                 else
 726                         SetPageError(page);
 727                 unlock_page(page);
 728                 page_cache_release(page);
 729         }
 730         if (req->ff)
 731                 fuse_file_put(req->ff, false);
 732 }
 733
 734 static void fuse_send_readpages(struct fuse_req *req, struct file *file)
 735 {
 736         struct fuse_file *ff = file->private_data;
 737         struct fuse_conn *fc = ff->fc;
 738         loff_t pos = page_offset(req->pages[0]);
 739         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 740
 741         req->out.argpages = 1;
 742         req->out.page_zeroing = 1;
 743         req->out.page_replace = 1;
 744         fuse_read_fill(req, file, pos, count, FUSE_READ);
 745         req->misc.read.attr_ver = fuse_get_attr_version(fc);
 746         if (fc->async_read) {
 747                 req->ff = fuse_file_get(ff);
 748                 req->end = fuse_readpages_end;
 749                 fuse_request_send_background(fc, req);
 750         } else {
 751                 fuse_request_send(fc, req);
 752                 fuse_readpages_end(fc, req);
 753                 fuse_put_request(fc, req);
 754         }
 755 }
 756
 757 struct fuse_fill_data {
 758         struct fuse_req *req;
 759         struct file *file;
 760         struct inode *inode;
 761         unsigned nr_pages;
 762 };
 763
 764 static int fuse_readpages_fill(void *_data, struct page *page)
 765 {
 766         struct fuse_fill_data *data = _data;
 767         struct fuse_req *req = data->req;
 768         struct inode *inode = data->inode;
 769         struct fuse_conn *fc = get_fuse_conn(inode);
 770
 771         fuse_wait_on_page_writeback(inode, page->index);
 772
 773         if (req->num_pages &&
 774             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 775              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 776              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 777                 int nr_alloc = min_t(unsigned, data->nr_pages,
 778                                      FUSE_MAX_PAGES_PER_REQ);
 779                 fuse_send_readpages(req, data->file);
 780                 if (fc->async_read)
 781                         req = fuse_get_req_for_background(fc, nr_alloc);
 782                 else
 783                         req = fuse_get_req(fc, nr_alloc);
 784
 785                 data->req = req;
 786                 if (IS_ERR(req)) {
 787                         unlock_page(page);
 788                         return PTR_ERR(req);
 789                 }
 790         }
 791
 792         if (WARN_ON(req->num_pages >= req->max_pages)) {
 793                 fuse_put_request(fc, req);
 794                 return -EIO;
 795         }
 796
 797         page_cache_get(page);
 798         req->pages[req->num_pages] = page;
 799         req->page_descs[req->num_pages].length = PAGE_SIZE;
 800         req->num_pages++;
 801         data->nr_pages--;
 802         return 0;
 803 }
 804
 805 static int fuse_readpages(struct file *file, struct address_space *mapping,
 806                           struct list_head *pages, unsigned nr_pages)
 807 {
 808         struct inode *inode = mapping->host;
 809         struct fuse_conn *fc = get_fuse_conn(inode);
 810         struct fuse_fill_data data;
 811         int err;
 812         int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
 813
 814         err = -EIO;
 815         if (is_bad_inode(inode))
 816                 goto out;
 817
 818         data.file = file;
 819         data.inode = inode;
 820         if (fc->async_read)
 821                 data.req = fuse_get_req_for_background(fc, nr_alloc);
 822         else
 823                 data.req = fuse_get_req(fc, nr_alloc);
 824         data.nr_pages = nr_pages;
 825         err = PTR_ERR(data.req);
 826         if (IS_ERR(data.req))
 827                 goto out;
 828
 829         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 830         if (!err) {
 831                 if (data.req->num_pages)
 832                         fuse_send_readpages(data.req, file);
 833                 else
 834                         fuse_put_request(fc, data.req);
 835         }
 836 out:
 837         return err;
 838 }
 839
 840 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 841                                   unsigned long nr_segs, loff_t pos)
 842 {
 843         struct inode *inode = iocb->ki_filp->f_mapping->host;
 844         struct fuse_conn *fc = get_fuse_conn(inode);
 845
 846         /*
 847          * In auto invalidate mode, always update attributes on read.
 848          * Otherwise, only update if we attempt to read past EOF (to ensure
 849          * i_size is up to date).
 850          */
 851         if (fc->auto_inval_data ||
 852             (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
 853                 int err;
 854                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 855                 if (err)
 856                         return err;
 857         }
 858
 859         return generic_file_aio_read(iocb, iov, nr_segs, pos);
 860 }
 861
 862 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 863                             loff_t pos, size_t count)
 864 {
 865         struct fuse_write_in *inarg = &req->misc.write.in;
 866         struct fuse_write_out *outarg = &req->misc.write.out;
 867
 868         inarg->fh = ff->fh;
 869         inarg->offset = pos;
 870         inarg->size = count;
 871         req->in.h.opcode = FUSE_WRITE;
 872         req->in.h.nodeid = ff->nodeid;
 873         req->in.numargs = 2;
 874         if (ff->fc->minor < 9)
 875                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 876         else
 877                 req->in.args[0].size = sizeof(struct fuse_write_in);
 878         req->in.args[0].value = inarg;
 879         req->in.args[1].size = count;
 880         req->out.numargs = 1;
 881         req->out.args[0].size = sizeof(struct fuse_write_out);
 882         req->out.args[0].value = outarg;
 883 }
 884
 885 static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
 886                               loff_t pos, size_t count, fl_owner_t owner)
 887 {
 888         struct file *file = io->file;
 889         struct fuse_file *ff = file->private_data;
 890         struct fuse_conn *fc = ff->fc;
 891         struct fuse_write_in *inarg = &req->misc.write.in;
 892
 893         fuse_write_fill(req, ff, pos, count);
 894         inarg->flags = file->f_flags;
 895         if (owner != NULL) {
 896                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 897                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 898         }
 899
 900         if (io->async)
 901                 return fuse_async_req_send(fc, req, count, io);
 902
 903         fuse_request_send(fc, req);
 904         return req->misc.write.out.size;
 905 }
 906
 907 void fuse_write_update_size(struct inode *inode, loff_t pos)
 908 {
 909         struct fuse_conn *fc = get_fuse_conn(inode);
 910         struct fuse_inode *fi = get_fuse_inode(inode);
 911
 912         spin_lock(&fc->lock);
 913         fi->attr_version = ++fc->attr_version;
 914         if (pos > inode->i_size)
 915                 i_size_write(inode, pos);
 916         spin_unlock(&fc->lock);
 917 }
 918
 919 static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
 920                                     struct inode *inode, loff_t pos,
 921                                     size_t count)
 922 {
 923         size_t res;
 924         unsigned offset;
 925         unsigned i;
 926         struct fuse_io_priv io = { .async = 0, .file = file };
 927
 928         for (i = 0; i < req->num_pages; i++)
 929                 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
 930
 931         res = fuse_send_write(req, &io, pos, count, NULL);
 932
 933         offset = req->page_descs[0].offset;
 934         count = res;
 935         for (i = 0; i < req->num_pages; i++) {
 936                 struct page *page = req->pages[i];
 937
 938                 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
 939                         SetPageUptodate(page);
 940
 941                 if (count > PAGE_CACHE_SIZE - offset)
 942                         count -= PAGE_CACHE_SIZE - offset;
 943                 else
 944                         count = 0;
 945                 offset = 0;
 946
 947                 unlock_page(page);
 948                 page_cache_release(page);
 949         }
 950
 951         return res;
 952 }
 953
 954 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
 955                                struct address_space *mapping,
 956                                struct iov_iter *ii, loff_t pos)
 957 {
 958         struct fuse_conn *fc = get_fuse_conn(mapping->host);
 959         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 960         size_t count = 0;
 961         int err;
 962
 963         req->in.argpages = 1;
 964         req->page_descs[0].offset = offset;
 965
 966         do {
 967                 size_t tmp;
 968                 struct page *page;
 969                 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 970                 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
 971                                      iov_iter_count(ii));
 972
 973                 bytes = min_t(size_t, bytes, fc->max_write - count);
 974
 975  again:
 976                 err = -EFAULT;
 977                 if (iov_iter_fault_in_readable(ii, bytes))
 978                         break;
 979
 980                 err = -ENOMEM;
 981                 page = grab_cache_page_write_begin(mapping, index, 0);
 982                 if (!page)
 983                         break;
 984
 985                 if (mapping_writably_mapped(mapping))
 986                         flush_dcache_page(page);
 987
 988                 pagefault_disable();
 989                 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
 990                 pagefault_enable();
 991                 flush_dcache_page(page);
 992
 993                 mark_page_accessed(page);
 994
 995                 if (!tmp) {
 996                         unlock_page(page);
 997                         page_cache_release(page);
 998                         bytes = min(bytes, iov_iter_single_seg_count(ii));
 999                         goto again;
1000                 }
1001
1002                 err = 0;
1003                 req->pages[req->num_pages] = page;
1004                 req->page_descs[req->num_pages].length = tmp;
1005                 req->num_pages++;
1006
1007                 iov_iter_advance(ii, tmp);
1008                 count += tmp;
1009                 pos += tmp;
1010                 offset += tmp;
1011                 if (offset == PAGE_CACHE_SIZE)
1012                         offset = 0;
1013
1014                 if (!fc->big_writes)
1015                         break;
1016         } while (iov_iter_count(ii) && count < fc->max_write &&
1017                  req->num_pages < req->max_pages && offset == 0);
1018
1019         return count > 0 ? count : err;
1020 }
1021
1022 static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
1023 {
1024         return min_t(unsigned,
1025                      ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
1026                      (pos >> PAGE_CACHE_SHIFT) + 1,
1027                      FUSE_MAX_PAGES_PER_REQ);
1028 }
1029
1030 static ssize_t fuse_perform_write(struct file *file,
1031                                   struct address_space *mapping,
1032                                   struct iov_iter *ii, loff_t pos)
1033 {
1034         struct inode *inode = mapping->host;
1035         struct fuse_conn *fc = get_fuse_conn(inode);
1036         int err = 0;
1037         ssize_t res = 0;
1038
1039         if (is_bad_inode(inode))
1040                 return -EIO;
1041
1042         do {
1043                 struct fuse_req *req;
1044                 ssize_t count;
1045                 unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
1046
1047                 req = fuse_get_req(fc, nr_pages);
1048                 if (IS_ERR(req)) {
1049                         err = PTR_ERR(req);
1050                         break;
1051                 }
1052
1053                 count = fuse_fill_write_pages(req, mapping, ii, pos);
1054                 if (count <= 0) {
1055                         err = count;
1056                 } else {
1057                         size_t num_written;
1058
1059                         num_written = fuse_send_write_pages(req, file, inode,
1060                                                             pos, count);
1061                         err = req->out.h.error;
1062                         if (!err) {
1063                                 res += num_written;
1064                                 pos += num_written;
1065
1066                                 /* break out of the loop on short write */
1067                                 if (num_written != count)
1068                                         err = -EIO;
1069                         }
1070                 }
1071                 fuse_put_request(fc, req);
1072         } while (!err && iov_iter_count(ii));
1073
1074         if (res > 0)
1075                 fuse_write_update_size(inode, pos);
1076
1077         fuse_invalidate_attr(inode);
1078
1079         return res > 0 ? res : err;
1080 }
1081
1082 static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
1083                                    unsigned long nr_segs, loff_t pos)
1084 {
1085         struct file *file = iocb->ki_filp;
1086         struct address_space *mapping = file->f_mapping;
1087         size_t count = 0;
1088         size_t ocount = 0;
1089         ssize_t written = 0;
1090         ssize_t written_buffered = 0;
1091         struct inode *inode = mapping->host;
1092         ssize_t err;
1093         struct iov_iter i;
1094         loff_t endbyte = 0;
1095
1096         WARN_ON(iocb->ki_pos != pos);
1097
1098         ocount = 0;
1099         err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1100         if (err)
1101                 return err;
1102
1103         count = ocount;
1104         mutex_lock(&inode->i_mutex);
1105
1106         /* We can write back this queue in page reclaim */
1107         current->backing_dev_info = mapping->backing_dev_info;
1108
1109         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1110         if (err)
1111                 goto out;
1112
1113         if (count == 0)
1114                 goto out;
1115
1116         err = file_remove_suid(file);
1117         if (err)
1118                 goto out;
1119
1120         err = file_update_time(file);
1121         if (err)
1122                 goto out;
1123
1124         if (file->f_flags & O_DIRECT) {
1125                 written = generic_file_direct_write(iocb, iov, &nr_segs,
1126                                                     pos, &iocb->ki_pos,
1127                                                     count, ocount);
1128                 if (written < 0 || written == count)
1129                         goto out;
1130
1131                 pos += written;
1132                 count -= written;
1133
1134                 iov_iter_init(&i, iov, nr_segs, count, written);
1135                 written_buffered = fuse_perform_write(file, mapping, &i, pos);
1136                 if (written_buffered < 0) {
1137                         err = written_buffered;
1138                         goto out;
1139                 }
1140                 endbyte = pos + written_buffered - 1;
1141
1142                 err = filemap_write_and_wait_range(file->f_mapping, pos,
1143                                                    endbyte);
1144                 if (err)
1145                         goto out;
1146
1147                 invalidate_mapping_pages(file->f_mapping,
1148                                          pos >> PAGE_CACHE_SHIFT,
1149                                          endbyte >> PAGE_CACHE_SHIFT);
1150
1151                 written += written_buffered;
1152                 iocb->ki_pos = pos + written_buffered;
1153         } else {
1154                 iov_iter_init(&i, iov, nr_segs, count, 0);
1155                 written = fuse_perform_write(file, mapping, &i, pos);
1156                 if (written >= 0)
1157                         iocb->ki_pos = pos + written;
1158         }
1159 out:
1160         current->backing_dev_info = NULL;
1161         mutex_unlock(&inode->i_mutex);
1162
1163         return written ? written : err;
1164 }
1165
1166 static inline void fuse_page_descs_length_init(struct fuse_req *req,
1167                 unsigned index, unsigned nr_pages)
1168 {
1169         int i;
1170
1171         for (i = index; i < index + nr_pages; i++)
1172                 req->page_descs[i].length = PAGE_SIZE -
1173                         req->page_descs[i].offset;
1174 }
1175
1176 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1177 {
1178         return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1179 }
1180
1181 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1182                                         size_t max_size)
1183 {
1184         return min(iov_iter_single_seg_count(ii), max_size);
1185 }
1186
1187 static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1188                                size_t *nbytesp, int write)
1189 {
1190         size_t nbytes = 0;  /* # bytes already packed in req */
1191
1192         /* Special case for kernel I/O: can copy directly into the buffer */
1193         if (segment_eq(get_fs(), KERNEL_DS)) {
1194                 unsigned long user_addr = fuse_get_user_addr(ii);
1195                 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1196
1197                 if (write)
1198                         req->in.args[1].value = (void *) user_addr;
1199                 else
1200                         req->out.args[0].value = (void *) user_addr;
1201
1202                 iov_iter_advance(ii, frag_size);
1203                 *nbytesp = frag_size;
1204                 return 0;
1205         }
1206
1207         while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1208                 unsigned npages;
1209                 unsigned long user_addr = fuse_get_user_addr(ii);
1210                 unsigned offset = user_addr & ~PAGE_MASK;
1211                 size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
1212                 int ret;
1213
1214                 unsigned n = req->max_pages - req->num_pages;
1215                 frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);
1216
1217                 npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1218                 npages = clamp(npages, 1U, n);
1219
1220                 ret = get_user_pages_fast(user_addr, npages, !write,
1221                                           &req->pages[req->num_pages]);
1222                 if (ret < 0)
1223                         return ret;
1224
1225                 npages = ret;
1226                 frag_size = min_t(size_t, frag_size,
1227                                   (npages << PAGE_SHIFT) - offset);
1228                 iov_iter_advance(ii, frag_size);
1229
1230                 req->page_descs[req->num_pages].offset = offset;
1231                 fuse_page_descs_length_init(req, req->num_pages, npages);
1232
1233                 req->num_pages += npages;
1234                 req->page_descs[req->num_pages - 1].length -=
1235                         (npages << PAGE_SHIFT) - offset - frag_size;
1236
1237                 nbytes += frag_size;
1238         }
1239
1240         if (write)
1241                 req->in.argpages = 1;
1242         else
1243                 req->out.argpages = 1;
1244
1245         *nbytesp = nbytes;
1246
1247         return 0;
1248 }
1249
1250 static inline int fuse_iter_npages(const struct iov_iter *ii_p)
1251 {
1252         struct iov_iter ii = *ii_p;
1253         int npages = 0;
1254
1255         while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
1256                 unsigned long user_addr = fuse_get_user_addr(&ii);
1257                 unsigned offset = user_addr & ~PAGE_MASK;
1258                 size_t frag_size = iov_iter_single_seg_count(&ii);
1259
1260                 npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1261                 iov_iter_advance(&ii, frag_size);
1262         }
1263
1264         return min(npages, FUSE_MAX_PAGES_PER_REQ);
1265 }
1266
1267 ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
1268                        unsigned long nr_segs, size_t count, loff_t *ppos,
1269                        int write)
1270 {
1271         struct file *file = io->file;
1272         struct fuse_file *ff = file->private_data;
1273         struct fuse_conn *fc = ff->fc;
1274         size_t nmax = write ? fc->max_write : fc->max_read;
1275         loff_t pos = *ppos;
1276         ssize_t res = 0;
1277         struct fuse_req *req;
1278         struct iov_iter ii;
1279
1280         iov_iter_init(&ii, iov, nr_segs, count, 0);
1281
1282         if (io->async)
1283                 req = fuse_get_req_for_background(fc, fuse_iter_npages(&ii));
1284         else
1285                 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1286         if (IS_ERR(req))
1287                 return PTR_ERR(req);
1288
1289         while (count) {
1290                 size_t nres;
1291                 fl_owner_t owner = current->files;
1292                 size_t nbytes = min(count, nmax);
1293                 int err = fuse_get_user_pages(req, &ii, &nbytes, write);
1294                 if (err) {
1295                         res = err;
1296                         break;
1297                 }
1298
1299                 if (write)
1300                         nres = fuse_send_write(req, io, pos, nbytes, owner);
1301                 else
1302                         nres = fuse_send_read(req, io, pos, nbytes, owner);
1303
1304                 if (!io->async)
1305                         fuse_release_user_pages(req, !write);
1306                 if (req->out.h.error) {
1307                         if (!res)
1308                                 res = req->out.h.error;
1309                         break;
1310                 } else if (nres > nbytes) {
1311                         res = -EIO;
1312                         break;
1313                 }
1314                 count -= nres;
1315                 res += nres;
1316                 pos += nres;
1317                 if (nres != nbytes)
1318                         break;
1319                 if (count) {
1320                         fuse_put_request(fc, req);
1321                         if (io->async)
1322                                 req = fuse_get_req_for_background(fc,
1323                                         fuse_iter_npages(&ii));
1324                         else
1325                                 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1326                         if (IS_ERR(req))
1327                                 break;
1328                 }
1329         }
1330         if (!IS_ERR(req))
1331                 fuse_put_request(fc, req);
1332         if (res > 0)
1333                 *ppos = pos;
1334
1335         return res;
1336 }
1337 EXPORT_SYMBOL_GPL(fuse_direct_io);
1338
1339 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1340                                   const struct iovec *iov,
1341                                   unsigned long nr_segs, loff_t *ppos,
1342                                   size_t count)
1343 {
1344         ssize_t res;
1345         struct file *file = io->file;
1346         struct inode *inode = file_inode(file);
1347
1348         if (is_bad_inode(inode))
1349                 return -EIO;
1350
1351         res = fuse_direct_io(io, iov, nr_segs, count, ppos, 0);
1352
1353         fuse_invalidate_attr(inode);
1354
1355         return res;
1356 }
1357
1358 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1359                                      size_t count, loff_t *ppos)
1360 {
1361         struct fuse_io_priv io = { .async = 0, .file = file };
1362         struct iovec iov = { .iov_base = buf, .iov_len = count };
1363         return __fuse_direct_read(&io, &iov, 1, ppos, count);
1364 }
1365
1366 static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
1367                                    const struct iovec *iov,
1368                                    unsigned long nr_segs, loff_t *ppos)
1369 {
1370         struct file *file = io->file;
1371         struct inode *inode = file_inode(file);
1372         size_t count = iov_length(iov, nr_segs);
1373         ssize_t res;
1374
1375         res = generic_write_checks(file, ppos, &count, 0);
1376         if (!res)
1377                 res = fuse_direct_io(io, iov, nr_segs, count, ppos, 1);
1378
1379         fuse_invalidate_attr(inode);
1380
1381         return res;
1382 }
1383
1384 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1385                                  size_t count, loff_t *ppos)
1386 {
1387         struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
1388         struct inode *inode = file_inode(file);
1389         ssize_t res;
1390         struct fuse_io_priv io = { .async = 0, .file = file };
1391
1392         if (is_bad_inode(inode))
1393                 return -EIO;
1394
1395         /* Don't allow parallel writes to the same file */
1396         mutex_lock(&inode->i_mutex);
1397         res = __fuse_direct_write(&io, &iov, 1, ppos);
1398         if (res > 0)
1399                 fuse_write_update_size(inode, *ppos);
1400         mutex_unlock(&inode->i_mutex);
1401
1402         return res;
1403 }
1404
1405 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1406 {
1407         __free_page(req->pages[0]);
1408         fuse_file_put(req->ff, false);
1409 }
1410
1411 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1412 {
1413         struct inode *inode = req->inode;
1414         struct fuse_inode *fi = get_fuse_inode(inode);
1415         struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1416
1417         list_del(&req->writepages_entry);
1418         dec_bdi_stat(bdi, BDI_WRITEBACK);
1419         dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
1420         bdi_writeout_inc(bdi);
1421         wake_up(&fi->page_waitq);
1422 }
1423
1424 /* Called under fc->lock, may release and reacquire it */
1425 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
1426 __releases(fc->lock)
1427 __acquires(fc->lock)
1428 {
1429         struct fuse_inode *fi = get_fuse_inode(req->inode);
1430         loff_t size = i_size_read(req->inode);
1431         struct fuse_write_in *inarg = &req->misc.write.in;
1432
1433         if (!fc->connected)
1434                 goto out_free;
1435
1436         if (inarg->offset + PAGE_CACHE_SIZE <= size) {
1437                 inarg->size = PAGE_CACHE_SIZE;
1438         } else if (inarg->offset < size) {
1439                 inarg->size = size & (PAGE_CACHE_SIZE - 1);
1440         } else {
1441                 /* Got truncated off completely */
1442                 goto out_free;
1443         }
1444
1445         req->in.args[1].size = inarg->size;
1446         fi->writectr++;
1447         fuse_request_send_background_locked(fc, req);
1448         return;
1449
1450  out_free:
1451         fuse_writepage_finish(fc, req);
1452         spin_unlock(&fc->lock);
1453         fuse_writepage_free(fc, req);
1454         fuse_put_request(fc, req);
1455         spin_lock(&fc->lock);
1456 }
1457
1458 /*
1459  * If fi->writectr is positive (no truncate or fsync going on) send
1460  * all queued writepage requests.
1461  *
1462  * Called with fc->lock
1463  */
1464 void fuse_flush_writepages(struct inode *inode)
1465 __releases(fc->lock)
1466 __acquires(fc->lock)
1467 {
1468         struct fuse_conn *fc = get_fuse_conn(inode);
1469         struct fuse_inode *fi = get_fuse_inode(inode);
1470         struct fuse_req *req;
1471
1472         while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1473                 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1474                 list_del_init(&req->list);
1475                 fuse_send_writepage(fc, req);
1476         }
1477 }
1478
1479 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1480 {
1481         struct inode *inode = req->inode;
1482         struct fuse_inode *fi = get_fuse_inode(inode);
1483
1484         mapping_set_error(inode->i_mapping, req->out.h.error);
1485         spin_lock(&fc->lock);
1486         fi->writectr--;
1487         fuse_writepage_finish(fc, req);
1488         spin_unlock(&fc->lock);
1489         fuse_writepage_free(fc, req);
1490 }
1491
1492 static int fuse_writepage_locked(struct page *page)
1493 {
1494         struct address_space *mapping = page->mapping;
1495         struct inode *inode = mapping->host;
1496         struct fuse_conn *fc = get_fuse_conn(inode);
1497         struct fuse_inode *fi = get_fuse_inode(inode);
1498         struct fuse_req *req;
1499         struct fuse_file *ff;
1500         struct page *tmp_page;
1501
1502         set_page_writeback(page);
1503
1504         req = fuse_request_alloc_nofs(1);
1505         if (!req)
1506                 goto err;
1507
1508         req->background = 1; /* writeback always goes to bg_queue */
1509         tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1510         if (!tmp_page)
1511                 goto err_free;
1512
1513         spin_lock(&fc->lock);
1514         BUG_ON(list_empty(&fi->write_files));
1515         ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
1516         req->ff = fuse_file_get(ff);
1517         spin_unlock(&fc->lock);
1518
1519         fuse_write_fill(req, ff, page_offset(page), 0);
1520
1521         copy_highpage(tmp_page, page);
1522         req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1523         req->in.argpages = 1;
1524         req->num_pages = 1;
1525         req->pages[0] = tmp_page;
1526         req->page_descs[0].offset = 0;
1527         req->page_descs[0].length = PAGE_SIZE;
1528         req->end = fuse_writepage_end;
1529         req->inode = inode;
1530
1531         inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1532         inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1533         end_page_writeback(page);
1534
1535         spin_lock(&fc->lock);
1536         list_add(&req->writepages_entry, &fi->writepages);
1537         list_add_tail(&req->list, &fi->queued_writes);
1538         fuse_flush_writepages(inode);
1539         spin_unlock(&fc->lock);
1540
1541         return 0;
1542
1543 err_free:
1544         fuse_request_free(req);
1545 err:
1546         end_page_writeback(page);
1547         return -ENOMEM;
1548 }
1549
1550 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1551 {
1552         int err;
1553
1554         err = fuse_writepage_locked(page);
1555         unlock_page(page);
1556
1557         return err;
1558 }
1559
1560 static int fuse_launder_page(struct page *page)
1561 {
1562         int err = 0;
1563         if (clear_page_dirty_for_io(page)) {
1564                 struct inode *inode = page->mapping->host;
1565                 err = fuse_writepage_locked(page);
1566                 if (!err)
1567                         fuse_wait_on_page_writeback(inode, page->index);
1568         }
1569         return err;
1570 }
1571
1572 /*
1573  * Write back dirty pages now, because there may not be any suitable
1574  * open files later
1575  */
1576 static void fuse_vma_close(struct vm_area_struct *vma)
1577 {
1578         filemap_write_and_wait(vma->vm_file->f_mapping);
1579 }
1580
1581 /*
1582  * Wait for writeback against this page to complete before allowing it
1583  * to be marked dirty again, and hence written back again, possibly
1584  * before the previous writepage completed.
1585  *
1586  * Block here, instead of in ->writepage(), so that the userspace fs
1587  * can only block processes actually operating on the filesystem.
1588  *
1589  * Otherwise unprivileged userspace fs would be able to block
1590  * unrelated:
1591  *
1592  * - page migration
1593  * - sync(2)
1594  * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
1595  */
1596 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1597 {
1598         struct page *page = vmf->page;
1599         /*
1600          * Don't use page->mapping as it may become NULL from a
1601          * concurrent truncate.
1602          */
1603         struct inode *inode = vma->vm_file->f_mapping->host;
1604
1605         fuse_wait_on_page_writeback(inode, page->index);
1606         return 0;
1607 }
1608
1609 static const struct vm_operations_struct fuse_file_vm_ops = {
1610         .close          = fuse_vma_close,
1611         .fault          = filemap_fault,
1612         .page_mkwrite   = fuse_page_mkwrite,
1613         .remap_pages    = generic_file_remap_pages,
1614 };
1615
1616 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
1617 {
1618         if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
1619                 struct inode *inode = file_inode(file);
1620                 struct fuse_conn *fc = get_fuse_conn(inode);
1621                 struct fuse_inode *fi = get_fuse_inode(inode);
1622                 struct fuse_file *ff = file->private_data;
1623                 /*
1624                  * file may be written through mmap, so chain it onto the
1625                  * inodes's write_file list
1626                  */
1627                 spin_lock(&fc->lock);
1628                 if (list_empty(&ff->write_entry))
1629                         list_add(&ff->write_entry, &fi->write_files);
1630                 spin_unlock(&fc->lock);
1631         }
1632         file_accessed(file);
1633         vma->vm_ops = &fuse_file_vm_ops;
1634         return 0;
1635 }
1636
1637 static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
1638 {
1639         /* Can't provide the coherency needed for MAP_SHARED */
1640         if (vma->vm_flags & VM_MAYSHARE)
1641                 return -ENODEV;
1642
1643         invalidate_inode_pages2(file->f_mapping);
1644
1645         return generic_file_mmap(file, vma);
1646 }
1647
1648 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
1649                                   struct file_lock *fl)
1650 {
1651         switch (ffl->type) {
1652         case F_UNLCK:
1653                 break;
1654
1655         case F_RDLCK:
1656         case F_WRLCK:
1657                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
1658                     ffl->end < ffl->start)
1659                         return -EIO;
1660
1661                 fl->fl_start = ffl->start;
1662                 fl->fl_end = ffl->end;
1663                 fl->fl_pid = ffl->pid;
1664                 break;
1665
1666         default:
1667                 return -EIO;
1668         }
1669         fl->fl_type = ffl->type;
1670         return 0;
1671 }
1672
1673 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1674                          const struct file_lock *fl, int opcode, pid_t pid,
1675                          int flock)
1676 {
1677         struct inode *inode = file_inode(file);
1678         struct fuse_conn *fc = get_fuse_conn(inode);
1679         struct fuse_file *ff = file->private_data;
1680         struct fuse_lk_in *arg = &req->misc.lk_in;
1681
1682         arg->fh = ff->fh;
1683         arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1684         arg->lk.start = fl->fl_start;
1685         arg->lk.end = fl->fl_end;
1686         arg->lk.type = fl->fl_type;
1687         arg->lk.pid = pid;
1688         if (flock)
1689                 arg->lk_flags |= FUSE_LK_FLOCK;
1690         req->in.h.opcode = opcode;
1691         req->in.h.nodeid = get_node_id(inode);
1692         req->in.numargs = 1;
1693         req->in.args[0].size = sizeof(*arg);
1694         req->in.args[0].value = arg;
1695 }
1696
1697 static int fuse_getlk(struct file *file, struct file_lock *fl)
1698 {
1699         struct inode *inode = file_inode(file);
1700         struct fuse_conn *fc = get_fuse_conn(inode);
1701         struct fuse_req *req;
1702         struct fuse_lk_out outarg;
1703         int err;
1704
1705         req = fuse_get_req_nopages(fc);
1706         if (IS_ERR(req))
1707                 return PTR_ERR(req);
1708
1709         fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1710         req->out.numargs = 1;
1711         req->out.args[0].size = sizeof(outarg);
1712         req->out.args[0].value = &outarg;
1713         fuse_request_send(fc, req);
1714         err = req->out.h.error;
1715         fuse_put_request(fc, req);
1716         if (!err)
1717                 err = convert_fuse_file_lock(&outarg.lk, fl);
1718
1719         return err;
1720 }
1721
1722 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1723 {
1724         struct inode *inode = file_inode(file);
1725         struct fuse_conn *fc = get_fuse_conn(inode);
1726         struct fuse_req *req;
1727         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
1728         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
1729         int err;
1730
1731         if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
1732                 /* NLM needs asynchronous locks, which we don't support yet */
1733                 return -ENOLCK;
1734         }
1735
1736         /* Unlock on close is handled by the flush method */
1737         if (fl->fl_flags & FL_CLOSE)
1738                 return 0;
1739
1740         req = fuse_get_req_nopages(fc);
1741         if (IS_ERR(req))
1742                 return PTR_ERR(req);
1743
1744         fuse_lk_fill(req, file, fl, opcode, pid, flock);
1745         fuse_request_send(fc, req);
1746         err = req->out.h.error;
1747         /* locking is restartable */
1748         if (err == -EINTR)
1749                 err = -ERESTARTSYS;
1750         fuse_put_request(fc, req);
1751         return err;
1752 }
1753
1754 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
1755 {
1756         struct inode *inode = file_inode(file);
1757         struct fuse_conn *fc = get_fuse_conn(inode);
1758         int err;
1759
1760         if (cmd == F_CANCELLK) {
1761                 err = 0;
1762         } else if (cmd == F_GETLK) {
1763                 if (fc->no_lock) {
1764                         posix_test_lock(file, fl);
1765                         err = 0;
1766                 } else
1767                         err = fuse_getlk(file, fl);
1768         } else {
1769                 if (fc->no_lock)
1770                         err = posix_lock_file(file, fl, NULL);
1771                 else
1772                         err = fuse_setlk(file, fl, 0);
1773         }
1774         return err;
1775 }
1776
1777 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
1778 {
1779         struct inode *inode = file_inode(file);
1780         struct fuse_conn *fc = get_fuse_conn(inode);
1781         int err;
1782
1783         if (fc->no_flock) {
1784                 err = flock_lock_file_wait(file, fl);
1785         } else {
1786                 struct fuse_file *ff = file->private_data;
1787
1788                 /* emulate flock with POSIX locks */
1789                 fl->fl_owner = (fl_owner_t) file;
1790                 ff->flock = true;
1791                 err = fuse_setlk(file, fl, 1);
1792         }
1793
1794         return err;
1795 }
1796
1797 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
1798 {
1799         struct inode *inode = mapping->host;
1800         struct fuse_conn *fc = get_fuse_conn(inode);
1801         struct fuse_req *req;
1802         struct fuse_bmap_in inarg;
1803         struct fuse_bmap_out outarg;
1804         int err;
1805
1806         if (!inode->i_sb->s_bdev || fc->no_bmap)
1807                 return 0;
1808
1809         req = fuse_get_req_nopages(fc);
1810         if (IS_ERR(req))
1811                 return 0;
1812
1813         memset(&inarg, 0, sizeof(inarg));
1814         inarg.block = block;
1815         inarg.blocksize = inode->i_sb->s_blocksize;
1816         req->in.h.opcode = FUSE_BMAP;
1817         req->in.h.nodeid = get_node_id(inode);
1818         req->in.numargs = 1;
1819         req->in.args[0].size = sizeof(inarg);
1820         req->in.args[0].value = &inarg;
1821         req->out.numargs = 1;
1822         req->out.args[0].size = sizeof(outarg);
1823         req->out.args[0].value = &outarg;
1824         fuse_request_send(fc, req);
1825         err = req->out.h.error;
1826         fuse_put_request(fc, req);
1827         if (err == -ENOSYS)
1828                 fc->no_bmap = 1;
1829
1830         return err ? 0 : outarg.block;
1831 }
1832
1833 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
1834 {
1835         loff_t retval;
1836         struct inode *inode = file_inode(file);
1837
1838         /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
1839         if (whence == SEEK_CUR || whence == SEEK_SET)
1840                 return generic_file_llseek(file, offset, whence);
1841
1842         mutex_lock(&inode->i_mutex);
1843         retval = fuse_update_attributes(inode, NULL, file, NULL);
1844         if (!retval)
1845                 retval = generic_file_llseek(file, offset, whence);
1846         mutex_unlock(&inode->i_mutex);
1847
1848         return retval;
1849 }
1850
1851 static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
1852                         unsigned int nr_segs, size_t bytes, bool to_user)
1853 {
1854         struct iov_iter ii;
1855         int page_idx = 0;
1856
1857         if (!bytes)
1858                 return 0;
1859
1860         iov_iter_init(&ii, iov, nr_segs, bytes, 0);
1861
1862         while (iov_iter_count(&ii)) {
1863                 struct page *page = pages[page_idx++];
1864                 size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
1865                 void *kaddr;
1866
1867                 kaddr = kmap(page);
1868
1869                 while (todo) {
1870                         char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
1871                         size_t iov_len = ii.iov->iov_len - ii.iov_offset;
1872                         size_t copy = min(todo, iov_len);
1873                         size_t left;
1874
1875                         if (!to_user)
1876                                 left = copy_from_user(kaddr, uaddr, copy);
1877                         else
1878                                 left = copy_to_user(uaddr, kaddr, copy);
1879
1880                         if (unlikely(left))
1881                                 return -EFAULT;
1882
1883                         iov_iter_advance(&ii, copy);
1884                         todo -= copy;
1885                         kaddr += copy;
1886                 }
1887
1888                 kunmap(page);
1889         }
1890
1891         return 0;
1892 }
1893
1894 /*
1895  * CUSE servers compiled on 32bit broke on 64bit kernels because the
1896  * ABI was defined to be 'struct iovec' which is different on 32bit
1897  * and 64bit.  Fortunately we can determine which structure the server
1898  * used from the size of the reply.
1899  */
1900 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
1901                                      size_t transferred, unsigned count,
1902                                      bool is_compat)
1903 {
1904 #ifdef CONFIG_COMPAT
1905         if (count * sizeof(struct compat_iovec) == transferred) {
1906                 struct compat_iovec *ciov = src;
1907                 unsigned i;
1908
1909                 /*
1910                  * With this interface a 32bit server cannot support
1911                  * non-compat (i.e. ones coming from 64bit apps) ioctl
1912                  * requests
1913                  */
1914                 if (!is_compat)
1915                         return -EINVAL;
1916
1917                 for (i = 0; i < count; i++) {
1918                         dst[i].iov_base = compat_ptr(ciov[i].iov_base);
1919                         dst[i].iov_len = ciov[i].iov_len;
1920                 }
1921                 return 0;
1922         }
1923 #endif
1924
1925         if (count * sizeof(struct iovec) != transferred)
1926                 return -EIO;
1927
1928         memcpy(dst, src, transferred);
1929         return 0;
1930 }
1931
1932 /* Make sure iov_length() won't overflow */
1933 static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
1934 {
1935         size_t n;
1936         u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
1937
1938         for (n = 0; n < count; n++, iov++) {
1939                 if (iov->iov_len > (size_t) max)
1940                         return -ENOMEM;
1941                 max -= iov->iov_len;
1942         }
1943         return 0;
1944 }
1945
1946 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
1947                                  void *src, size_t transferred, unsigned count,
1948                                  bool is_compat)
1949 {
1950         unsigned i;
1951         struct fuse_ioctl_iovec *fiov = src;
1952
1953         if (fc->minor < 16) {
1954                 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
1955                                                  count, is_compat);
1956         }
1957
1958         if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
1959                 return -EIO;
1960
1961         for (i = 0; i < count; i++) {
1962                 /* Did the server supply an inappropriate value? */
1963                 if (fiov[i].base != (unsigned long) fiov[i].base ||
1964                     fiov[i].len != (unsigned long) fiov[i].len)
1965                         return -EIO;
1966
1967                 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
1968                 dst[i].iov_len = (size_t) fiov[i].len;
1969
1970 #ifdef CONFIG_COMPAT
1971                 if (is_compat &&
1972                     (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
1973                      (compat_size_t) dst[i].iov_len != fiov[i].len))
1974                         return -EIO;
1975 #endif
1976         }
1977
1978         return 0;
1979 }
1980
1981
1982 /*
1983  * For ioctls, there is no generic way to determine how much memory
1984  * needs to be read and/or written.  Furthermore, ioctls are allowed
1985  * to dereference the passed pointer, so the parameter requires deep
1986  * copying but FUSE has no idea whatsoever about what to copy in or
1987  * out.
1988  *
1989  * This is solved by allowing FUSE server to retry ioctl with
1990  * necessary in/out iovecs.  Let's assume the ioctl implementation
1991  * needs to read in the following structure.
1992  *
1993  * struct a {
1994  *      char    *buf;
1995  *      size_t  buflen;
1996  * }
1997  *
1998  * On the first callout to FUSE server, inarg->in_size and
1999  * inarg->out_size will be NULL; then, the server completes the ioctl
2000  * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
2001  * the actual iov array to
2002  *
2003  * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a) } }
2004  *
2005  * which tells FUSE to copy in the requested area and retry the ioctl.
2006  * On the second round, the server has access to the structure and
2007  * from that it can tell what to look for next, so on the invocation,
2008  * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
2009  *
2010  * { { .iov_base = inarg.arg,   .iov_len = sizeof(struct a)     },
2011  *   { .iov_base = a.buf,       .iov_len = a.buflen             } }
2012  *
2013  * FUSE will copy both struct a and the pointed buffer from the
2014  * process doing the ioctl and retry ioctl with both struct a and the
2015  * buffer.
2016  *
2017  * This time, FUSE server has everything it needs and completes ioctl
2018  * without FUSE_IOCTL_RETRY which finishes the ioctl call.
2019  *
2020  * Copying data out works the same way.
2021  *
2022  * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
2023  * automatically initializes in and out iovs by decoding @cmd with
2024  * _IOC_* macros and the server is not allowed to request RETRY.  This
2025  * limits ioctl data transfers to well-formed ioctls and is the forced
2026  * behavior for all FUSE servers.
2027  */
2028 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
2029                    unsigned int flags)
2030 {
2031         struct fuse_file *ff = file->private_data;
2032         struct fuse_conn *fc = ff->fc;
2033         struct fuse_ioctl_in inarg = {
2034                 .fh = ff->fh,
2035                 .cmd = cmd,
2036                 .arg = arg,
2037                 .flags = flags
2038         };
2039         struct fuse_ioctl_out outarg;
2040         struct fuse_req *req = NULL;
2041         struct page **pages = NULL;
2042         struct iovec *iov_page = NULL;
2043         struct iovec *in_iov = NULL, *out_iov = NULL;
2044         unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
2045         size_t in_size, out_size, transferred;
2046         int err;
2047
2048 #if BITS_PER_LONG == 32
2049         inarg.flags |= FUSE_IOCTL_32BIT;
2050 #else
2051         if (flags & FUSE_IOCTL_COMPAT)
2052                 inarg.flags |= FUSE_IOCTL_32BIT;
2053 #endif
2054
2055         /* assume all the iovs returned by client always fits in a page */
2056         BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
2057
2058         err = -ENOMEM;
2059         pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
2060         iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
2061         if (!pages || !iov_page)
2062                 goto out;
2063
2064         /*
2065          * If restricted, initialize IO parameters as encoded in @cmd.
2066          * RETRY from server is not allowed.
2067          */
2068         if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
2069                 struct iovec *iov = iov_page;
2070
2071                 iov->iov_base = (void __user *)arg;
2072                 iov->iov_len = _IOC_SIZE(cmd);
2073
2074                 if (_IOC_DIR(cmd) & _IOC_WRITE) {
2075                         in_iov = iov;
2076                         in_iovs = 1;
2077                 }
2078
2079                 if (_IOC_DIR(cmd) & _IOC_READ) {
2080                         out_iov = iov;
2081                         out_iovs = 1;
2082                 }
2083         }
2084
2085  retry:
2086         inarg.in_size = in_size = iov_length(in_iov, in_iovs);
2087         inarg.out_size = out_size = iov_length(out_iov, out_iovs);
2088
2089         /*
2090          * Out data can be used either for actual out data or iovs,
2091          * make sure there always is at least one page.
2092          */
2093         out_size = max_t(size_t, out_size, PAGE_SIZE);
2094         max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
2095
2096         /* make sure there are enough buffer pages and init request with them */
2097         err = -ENOMEM;
2098         if (max_pages > FUSE_MAX_PAGES_PER_REQ)
2099                 goto out;
2100         while (num_pages < max_pages) {
2101                 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
2102                 if (!pages[num_pages])
2103                         goto out;
2104                 num_pages++;
2105         }
2106
2107         req = fuse_get_req(fc, num_pages);
2108         if (IS_ERR(req)) {
2109                 err = PTR_ERR(req);
2110                 req = NULL;
2111                 goto out;
2112         }
2113         memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
2114         req->num_pages = num_pages;
2115         fuse_page_descs_length_init(req, 0, req->num_pages);
2116
2117         /* okay, let's send it to the client */
2118         req->in.h.opcode = FUSE_IOCTL;
2119         req->in.h.nodeid = ff->nodeid;
2120         req->in.numargs = 1;
2121         req->in.args[0].size = sizeof(inarg);
2122         req->in.args[0].value = &inarg;
2123         if (in_size) {
2124                 req->in.numargs++;
2125                 req->in.args[1].size = in_size;
2126                 req->in.argpages = 1;
2127
2128                 err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
2129                                            false);
2130                 if (err)
2131                         goto out;
2132         }
2133
2134         req->out.numargs = 2;
2135         req->out.args[0].size = sizeof(outarg);
2136         req->out.args[0].value = &outarg;
2137         req->out.args[1].size = out_size;
2138         req->out.argpages = 1;
2139         req->out.argvar = 1;
2140
2141         fuse_request_send(fc, req);
2142         err = req->out.h.error;
2143         transferred = req->out.args[1].size;
2144         fuse_put_request(fc, req);
2145         req = NULL;
2146         if (err)
2147                 goto out;
2148
2149         /* did it ask for retry? */
2150         if (outarg.flags & FUSE_IOCTL_RETRY) {
2151                 void *vaddr;
2152
2153                 /* no retry if in restricted mode */
2154                 err = -EIO;
2155                 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
2156                         goto out;
2157
2158                 in_iovs = outarg.in_iovs;
2159                 out_iovs = outarg.out_iovs;
2160
2161                 /*
2162                  * Make sure things are in boundary, separate checks
2163                  * are to protect against overflow.
2164                  */
2165                 err = -ENOMEM;
2166                 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
2167                     out_iovs > FUSE_IOCTL_MAX_IOV ||
2168                     in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
2169                         goto out;
2170
2171                 vaddr = kmap_atomic(pages[0]);
2172                 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2173                                             transferred, in_iovs + out_iovs,
2174                                             (flags & FUSE_IOCTL_COMPAT) != 0);
2175                 kunmap_atomic(vaddr);
2176                 if (err)
2177                         goto out;
2178
2179                 in_iov = iov_page;
2180                 out_iov = in_iov + in_iovs;
2181
2182                 err = fuse_verify_ioctl_iov(in_iov, in_iovs);
2183                 if (err)
2184                         goto out;
2185
2186                 err = fuse_verify_ioctl_iov(out_iov, out_iovs);
2187                 if (err)
2188                         goto out;
2189
2190                 goto retry;
2191         }
2192
2193         err = -EIO;
2194         if (transferred > inarg.out_size)
2195                 goto out;
2196
2197         err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
2198  out:
2199         if (req)
2200                 fuse_put_request(fc, req);
2201         free_page((unsigned long) iov_page);
2202         while (num_pages)
2203                 __free_page(pages[--num_pages]);
2204         kfree(pages);
2205
2206         return err ? err : outarg.result;
2207 }
2208 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2209
2210 long fuse_ioctl_common(struct file *file, unsigned int cmd,
2211                        unsigned long arg, unsigned int flags)
2212 {
2213         struct inode *inode = file_inode(file);
2214         struct fuse_conn *fc = get_fuse_conn(inode);
2215
2216         if (!fuse_allow_current_process(fc))
2217                 return -EACCES;
2218
2219         if (is_bad_inode(inode))
2220                 return -EIO;
2221
2222         return fuse_do_ioctl(file, cmd, arg, flags);
2223 }
2224
2225 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2226                             unsigned long arg)
2227 {
2228         return fuse_ioctl_common(file, cmd, arg, 0);
2229 }
2230
2231 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2232                                    unsigned long arg)
2233 {
2234         return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2235 }
2236
2237 /*
2238  * All files which have been polled are linked to RB tree
2239  * fuse_conn->polled_files which is indexed by kh.  Walk the tree and
2240  * find the matching one.
2241  */
2242 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2243                                               struct rb_node **parent_out)
2244 {
2245         struct rb_node **link = &fc->polled_files.rb_node;
2246         struct rb_node *last = NULL;
2247
2248         while (*link) {
2249                 struct fuse_file *ff;
2250
2251                 last = *link;
2252                 ff = rb_entry(last, struct fuse_file, polled_node);
2253
2254                 if (kh < ff->kh)
2255                         link = &last->rb_left;
2256                 else if (kh > ff->kh)
2257                         link = &last->rb_right;
2258                 else
2259                         return link;
2260         }
2261
2262         if (parent_out)
2263                 *parent_out = last;
2264         return link;
2265 }
2266
2267 /*
2268  * The file is about to be polled.  Make sure it's on the polled_files
2269  * RB tree.  Note that files once added to the polled_files tree are
2270  * not removed before the file is released.  This is because a file
2271  * polled once is likely to be polled again.
2272  */
2273 static void fuse_register_polled_file(struct fuse_conn *fc,
2274                                       struct fuse_file *ff)
2275 {
2276         spin_lock(&fc->lock);
2277         if (RB_EMPTY_NODE(&ff->polled_node)) {
2278                 struct rb_node **link, *parent;
2279
2280                 link = fuse_find_polled_node(fc, ff->kh, &parent);
2281                 BUG_ON(*link);
2282                 rb_link_node(&ff->polled_node, parent, link);
2283                 rb_insert_color(&ff->polled_node, &fc->polled_files);
2284         }
2285         spin_unlock(&fc->lock);
2286 }
2287
2288 unsigned fuse_file_poll(struct file *file, poll_table *wait)
2289 {
2290         struct fuse_file *ff = file->private_data;
2291         struct fuse_conn *fc = ff->fc;
2292         struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2293         struct fuse_poll_out outarg;
2294         struct fuse_req *req;
2295         int err;
2296
2297         if (fc->no_poll)
2298                 return DEFAULT_POLLMASK;
2299
2300         poll_wait(file, &ff->poll_wait, wait);
2301         inarg.events = (__u32)poll_requested_events(wait);
2302
2303         /*
2304          * Ask for notification iff there's someone waiting for it.
2305          * The client may ignore the flag and always notify.
2306          */
2307         if (waitqueue_active(&ff->poll_wait)) {
2308                 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2309                 fuse_register_polled_file(fc, ff);
2310         }
2311
2312         req = fuse_get_req_nopages(fc);
2313         if (IS_ERR(req))
2314                 return POLLERR;
2315
2316         req->in.h.opcode = FUSE_POLL;
2317         req->in.h.nodeid = ff->nodeid;
2318         req->in.numargs = 1;
2319         req->in.args[0].size = sizeof(inarg);
2320         req->in.args[0].value = &inarg;
2321         req->out.numargs = 1;
2322         req->out.args[0].size = sizeof(outarg);
2323         req->out.args[0].value = &outarg;
2324         fuse_request_send(fc, req);
2325         err = req->out.h.error;
2326         fuse_put_request(fc, req);
2327
2328         if (!err)
2329                 return outarg.revents;
2330         if (err == -ENOSYS) {
2331                 fc->no_poll = 1;
2332                 return DEFAULT_POLLMASK;
2333         }
2334         return POLLERR;
2335 }
2336 EXPORT_SYMBOL_GPL(fuse_file_poll);
2337
2338 /*
2339  * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2340  * wakes up the poll waiters.
2341  */
2342 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2343                             struct fuse_notify_poll_wakeup_out *outarg)
2344 {
2345         u64 kh = outarg->kh;
2346         struct rb_node **link;
2347
2348         spin_lock(&fc->lock);
2349
2350         link = fuse_find_polled_node(fc, kh, NULL);
2351         if (*link) {
2352                 struct fuse_file *ff;
2353
2354                 ff = rb_entry(*link, struct fuse_file, polled_node);
2355                 wake_up_interruptible_sync(&ff->poll_wait);
2356         }
2357
2358         spin_unlock(&fc->lock);
2359         return 0;
2360 }
2361
2362 static void fuse_do_truncate(struct file *file)
2363 {
2364         struct inode *inode = file->f_mapping->host;
2365         struct iattr attr;
2366
2367         attr.ia_valid = ATTR_SIZE;
2368         attr.ia_size = i_size_read(inode);
2369
2370         attr.ia_file = file;
2371         attr.ia_valid |= ATTR_FILE;
2372
2373         fuse_do_setattr(inode, &attr, file);
2374 }
2375
2376 static inline loff_t fuse_round_up(loff_t off)
2377 {
2378         return round_up(off, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
2379 }
2380
2381 static ssize_t
2382 fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
2383                         loff_t offset, unsigned long nr_segs)
2384 {
2385         ssize_t ret = 0;
2386         struct file *file = iocb->ki_filp;
2387         struct fuse_file *ff = file->private_data;
2388         bool async_dio = ff->fc->async_dio;
2389         loff_t pos = 0;
2390         struct inode *inode;
2391         loff_t i_size;
2392         size_t count = iov_length(iov, nr_segs);
2393         struct fuse_io_priv *io;
2394
2395         pos = offset;
2396         inode = file->f_mapping->host;
2397         i_size = i_size_read(inode);
2398
2399         /* optimization for short read */
2400         if (async_dio && rw != WRITE && offset + count > i_size) {
2401                 if (offset >= i_size)
2402                         return 0;
2403                 count = min_t(loff_t, count, fuse_round_up(i_size - offset));
2404         }
2405
2406         io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2407         if (!io)
2408                 return -ENOMEM;
2409         spin_lock_init(&io->lock);
2410         io->reqs = 1;
2411         io->bytes = -1;
2412         io->size = 0;
2413         io->offset = offset;
2414         io->write = (rw == WRITE);
2415         io->err = 0;
2416         io->file = file;
2417         /*
2418          * By default, we want to optimize all I/Os with async request
2419          * submission to the client filesystem if supported.
2420          */
2421         io->async = async_dio;
2422         io->iocb = iocb;
2423
2424         /*
2425          * We cannot asynchronously extend the size of a file. We have no method
2426          * to wait on real async I/O requests, so we must submit this request
2427          * synchronously.
2428          */
2429         if (!is_sync_kiocb(iocb) && (offset + count > i_size) && rw == WRITE)
2430                 io->async = false;
2431
2432         if (rw == WRITE)
2433                 ret = __fuse_direct_write(io, iov, nr_segs, &pos);
2434         else
2435                 ret = __fuse_direct_read(io, iov, nr_segs, &pos, count);
2436
2437         if (io->async) {
2438                 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2439
2440                 /* we have a non-extending, async request, so return */
2441                 if (!is_sync_kiocb(iocb))
2442                         return -EIOCBQUEUED;
2443
2444                 ret = wait_on_sync_kiocb(iocb);
2445         } else {
2446                 kfree(io);
2447         }
2448
2449         if (rw == WRITE) {
2450                 if (ret > 0)
2451                         fuse_write_update_size(inode, pos);
2452                 else if (ret < 0 && offset + count > i_size)
2453                         fuse_do_truncate(file);
2454         }
2455
2456         return ret;
2457 }
2458
2459 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2460                                 loff_t length)
2461 {
2462         struct fuse_file *ff = file->private_data;
2463         struct inode *inode = file->f_inode;
2464         struct fuse_conn *fc = ff->fc;
2465         struct fuse_req *req;
2466         struct fuse_fallocate_in inarg = {
2467                 .fh = ff->fh,
2468                 .offset = offset,
2469                 .length = length,
2470                 .mode = mode
2471         };
2472         int err;
2473
2474         if (fc->no_fallocate)
2475                 return -EOPNOTSUPP;
2476
2477         if (mode & FALLOC_FL_PUNCH_HOLE) {
2478                 mutex_lock(&inode->i_mutex);
2479                 fuse_set_nowrite(inode);
2480         }
2481
2482         req = fuse_get_req_nopages(fc);
2483         if (IS_ERR(req)) {
2484                 err = PTR_ERR(req);
2485                 goto out;
2486         }
2487
2488         req->in.h.opcode = FUSE_FALLOCATE;
2489         req->in.h.nodeid = ff->nodeid;
2490         req->in.numargs = 1;
2491         req->in.args[0].size = sizeof(inarg);
2492         req->in.args[0].value = &inarg;
2493         fuse_request_send(fc, req);
2494         err = req->out.h.error;
2495         if (err == -ENOSYS) {
2496                 fc->no_fallocate = 1;
2497                 err = -EOPNOTSUPP;
2498         }
2499         fuse_put_request(fc, req);
2500
2501         if (err)
2502                 goto out;
2503
2504         /* we could have extended the file */
2505         if (!(mode & FALLOC_FL_KEEP_SIZE))
2506                 fuse_write_update_size(inode, offset + length);
2507
2508         if (mode & FALLOC_FL_PUNCH_HOLE)
2509                 truncate_pagecache_range(inode, offset, offset + length - 1);
2510
2511         fuse_invalidate_attr(inode);
2512
2513 out:
2514         if (mode & FALLOC_FL_PUNCH_HOLE) {
2515                 fuse_release_nowrite(inode);
2516                 mutex_unlock(&inode->i_mutex);
2517         }
2518
2519         return err;
2520 }
2521
2522 static const struct file_operations fuse_file_operations = {
2523         .llseek         = fuse_file_llseek,
2524         .read           = do_sync_read,
2525         .aio_read       = fuse_file_aio_read,
2526         .write          = do_sync_write,
2527         .aio_write      = fuse_file_aio_write,
2528         .mmap           = fuse_file_mmap,
2529         .open           = fuse_open,
2530         .flush          = fuse_flush,
2531         .release        = fuse_release,
2532         .fsync          = fuse_fsync,
2533         .lock           = fuse_file_lock,
2534         .flock          = fuse_file_flock,
2535         .splice_read    = generic_file_splice_read,
2536         .unlocked_ioctl = fuse_file_ioctl,
2537         .compat_ioctl   = fuse_file_compat_ioctl,
2538         .poll           = fuse_file_poll,
2539         .fallocate      = fuse_file_fallocate,
2540 };
2541
2542 static const struct file_operations fuse_direct_io_file_operations = {
2543         .llseek         = fuse_file_llseek,
2544         .read           = fuse_direct_read,
2545         .write          = fuse_direct_write,
2546         .mmap           = fuse_direct_mmap,
2547         .open           = fuse_open,
2548         .flush          = fuse_flush,
2549         .release        = fuse_release,
2550         .fsync          = fuse_fsync,
2551         .lock           = fuse_file_lock,
2552         .flock          = fuse_file_flock,
2553         .unlocked_ioctl = fuse_file_ioctl,
2554         .compat_ioctl   = fuse_file_compat_ioctl,
2555         .poll           = fuse_file_poll,
2556         .fallocate      = fuse_file_fallocate,
2557         /* no splice_read */
2558 };
2559
2560 static const struct address_space_operations fuse_file_aops  = {
2561         .readpage       = fuse_readpage,
2562         .writepage      = fuse_writepage,
2563         .launder_page   = fuse_launder_page,
2564         .readpages      = fuse_readpages,
2565         .set_page_dirty = __set_page_dirty_nobuffers,
2566         .bmap           = fuse_bmap,
2567         .direct_IO      = fuse_direct_IO,
2568 };
2569
2570 void fuse_init_file_inode(struct inode *inode)
2571 {
2572         inode->i_fop = &fuse_file_operations;
2573         inode->i_data.a_ops = &fuse_file_aops;
2574 }