fs/fuse/file.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2006  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
  16 static const struct file_operations fuse_direct_io_file_operations;
  17
  18 static int fuse_send_open(struct inode *inode, struct file *file, int isdir,
  19                           struct fuse_open_out *outargp)
  20 {
  21         struct fuse_conn *fc = get_fuse_conn(inode);
  22         struct fuse_open_in inarg;
  23         struct fuse_req *req;
  24         int err;
  25
  26         req = fuse_get_req(fc);
  27         if (IS_ERR(req))
  28                 return PTR_ERR(req);
  29
  30         memset(&inarg, 0, sizeof(inarg));
  31         inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
  32         if (!fc->atomic_o_trunc)
  33                 inarg.flags &= ~O_TRUNC;
  34         req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
  35         req->in.h.nodeid = get_node_id(inode);
  36         req->in.numargs = 1;
  37         req->in.args[0].size = sizeof(inarg);
  38         req->in.args[0].value = &inarg;
  39         req->out.numargs = 1;
  40         req->out.args[0].size = sizeof(*outargp);
  41         req->out.args[0].value = outargp;
  42         request_send(fc, req);
  43         err = req->out.h.error;
  44         fuse_put_request(fc, req);
  45
  46         return err;
  47 }
  48
  49 struct fuse_file *fuse_file_alloc(void)
  50 {
  51         struct fuse_file *ff;
  52         ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
  53         if (ff) {
  54                 ff->reserved_req = fuse_request_alloc();
  55                 if (!ff->reserved_req) {
  56                         kfree(ff);
  57                         ff = NULL;
  58                 } else {
  59                         INIT_LIST_HEAD(&ff->write_entry);
  60                         atomic_set(&ff->count, 0);
  61                 }
  62         }
  63         return ff;
  64 }
  65
  66 void fuse_file_free(struct fuse_file *ff)
  67 {
  68         fuse_request_free(ff->reserved_req);
  69         kfree(ff);
  70 }
  71
  72 static struct fuse_file *fuse_file_get(struct fuse_file *ff)
  73 {
  74         atomic_inc(&ff->count);
  75         return ff;
  76 }
  77
  78 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
  79 {
  80         dput(req->dentry);
  81         mntput(req->vfsmount);
  82         fuse_put_request(fc, req);
  83 }
  84
  85 static void fuse_file_put(struct fuse_file *ff)
  86 {
  87         if (atomic_dec_and_test(&ff->count)) {
  88                 struct fuse_req *req = ff->reserved_req;
  89                 struct fuse_conn *fc = get_fuse_conn(req->dentry->d_inode);
  90                 req->end = fuse_release_end;
  91                 request_send_background(fc, req);
  92                 kfree(ff);
  93         }
  94 }
  95
  96 void fuse_finish_open(struct inode *inode, struct file *file,
  97                       struct fuse_file *ff, struct fuse_open_out *outarg)
  98 {
  99         if (outarg->open_flags & FOPEN_DIRECT_IO)
 100                 file->f_op = &fuse_direct_io_file_operations;
 101         if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
 102                 invalidate_inode_pages2(inode->i_mapping);
 103         ff->fh = outarg->fh;
 104         file->private_data = fuse_file_get(ff);
 105 }
 106
 107 int fuse_open_common(struct inode *inode, struct file *file, int isdir)
 108 {
 109         struct fuse_open_out outarg;
 110         struct fuse_file *ff;
 111         int err;
 112
 113         /* VFS checks this, but only _after_ ->open() */
 114         if (file->f_flags & O_DIRECT)
 115                 return -EINVAL;
 116
 117         err = generic_file_open(inode, file);
 118         if (err)
 119                 return err;
 120
 121         ff = fuse_file_alloc();
 122         if (!ff)
 123                 return -ENOMEM;
 124
 125         err = fuse_send_open(inode, file, isdir, &outarg);
 126         if (err)
 127                 fuse_file_free(ff);
 128         else {
 129                 if (isdir)
 130                         outarg.open_flags &= ~FOPEN_DIRECT_IO;
 131                 fuse_finish_open(inode, file, ff, &outarg);
 132         }
 133
 134         return err;
 135 }
 136
 137 void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode)
 138 {
 139         struct fuse_req *req = ff->reserved_req;
 140         struct fuse_release_in *inarg = &req->misc.release_in;
 141
 142         inarg->fh = ff->fh;
 143         inarg->flags = flags;
 144         req->in.h.opcode = opcode;
 145         req->in.h.nodeid = nodeid;
 146         req->in.numargs = 1;
 147         req->in.args[0].size = sizeof(struct fuse_release_in);
 148         req->in.args[0].value = inarg;
 149 }
 150
 151 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
 152 {
 153         struct fuse_file *ff = file->private_data;
 154         if (ff) {
 155                 struct fuse_conn *fc = get_fuse_conn(inode);
 156
 157                 fuse_release_fill(ff, get_node_id(inode), file->f_flags,
 158                                   isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
 159
 160                 /* Hold vfsmount and dentry until release is finished */
 161                 ff->reserved_req->vfsmount = mntget(file->f_path.mnt);
 162                 ff->reserved_req->dentry = dget(file->f_path.dentry);
 163
 164                 spin_lock(&fc->lock);
 165                 list_del(&ff->write_entry);
 166                 spin_unlock(&fc->lock);
 167                 /*
 168                  * Normally this will send the RELEASE request,
 169                  * however if some asynchronous READ or WRITE requests
 170                  * are outstanding, the sending will be delayed
 171                  */
 172                 fuse_file_put(ff);
 173         }
 174
 175         /* Return value is ignored by VFS */
 176         return 0;
 177 }
 178
 179 static int fuse_open(struct inode *inode, struct file *file)
 180 {
 181         return fuse_open_common(inode, file, 0);
 182 }
 183
 184 static int fuse_release(struct inode *inode, struct file *file)
 185 {
 186         return fuse_release_common(inode, file, 0);
 187 }
 188
 189 /*
 190  * Scramble the ID space with XTEA, so that the value of the files_struct
 191  * pointer is not exposed to userspace.
 192  */
 193 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 194 {
 195         u32 *k = fc->scramble_key;
 196         u64 v = (unsigned long) id;
 197         u32 v0 = v;
 198         u32 v1 = v >> 32;
 199         u32 sum = 0;
 200         int i;
 201
 202         for (i = 0; i < 32; i++) {
 203                 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
 204                 sum += 0x9E3779B9;
 205                 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
 206         }
 207
 208         return (u64) v0 + ((u64) v1 << 32);
 209 }
 210
 211 static int fuse_flush(struct file *file, fl_owner_t id)
 212 {
 213         struct inode *inode = file->f_path.dentry->d_inode;
 214         struct fuse_conn *fc = get_fuse_conn(inode);
 215         struct fuse_file *ff = file->private_data;
 216         struct fuse_req *req;
 217         struct fuse_flush_in inarg;
 218         int err;
 219
 220         if (is_bad_inode(inode))
 221                 return -EIO;
 222
 223         if (fc->no_flush)
 224                 return 0;
 225
 226         req = fuse_get_req_nofail(fc, file);
 227         memset(&inarg, 0, sizeof(inarg));
 228         inarg.fh = ff->fh;
 229         inarg.lock_owner = fuse_lock_owner_id(fc, id);
 230         req->in.h.opcode = FUSE_FLUSH;
 231         req->in.h.nodeid = get_node_id(inode);
 232         req->in.numargs = 1;
 233         req->in.args[0].size = sizeof(inarg);
 234         req->in.args[0].value = &inarg;
 235         req->force = 1;
 236         request_send(fc, req);
 237         err = req->out.h.error;
 238         fuse_put_request(fc, req);
 239         if (err == -ENOSYS) {
 240                 fc->no_flush = 1;
 241                 err = 0;
 242         }
 243         return err;
 244 }
 245
 246 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 247                       int isdir)
 248 {
 249         struct inode *inode = de->d_inode;
 250         struct fuse_conn *fc = get_fuse_conn(inode);
 251         struct fuse_file *ff = file->private_data;
 252         struct fuse_req *req;
 253         struct fuse_fsync_in inarg;
 254         int err;
 255
 256         if (is_bad_inode(inode))
 257                 return -EIO;
 258
 259         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 260                 return 0;
 261
 262         req = fuse_get_req(fc);
 263         if (IS_ERR(req))
 264                 return PTR_ERR(req);
 265
 266         memset(&inarg, 0, sizeof(inarg));
 267         inarg.fh = ff->fh;
 268         inarg.fsync_flags = datasync ? 1 : 0;
 269         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 270         req->in.h.nodeid = get_node_id(inode);
 271         req->in.numargs = 1;
 272         req->in.args[0].size = sizeof(inarg);
 273         req->in.args[0].value = &inarg;
 274         request_send(fc, req);
 275         err = req->out.h.error;
 276         fuse_put_request(fc, req);
 277         if (err == -ENOSYS) {
 278                 if (isdir)
 279                         fc->no_fsyncdir = 1;
 280                 else
 281                         fc->no_fsync = 1;
 282                 err = 0;
 283         }
 284         return err;
 285 }
 286
 287 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 288 {
 289         return fuse_fsync_common(file, de, datasync, 0);
 290 }
 291
 292 void fuse_read_fill(struct fuse_req *req, struct file *file,
 293                     struct inode *inode, loff_t pos, size_t count, int opcode)
 294 {
 295         struct fuse_read_in *inarg = &req->misc.read_in;
 296         struct fuse_file *ff = file->private_data;
 297
 298         inarg->fh = ff->fh;
 299         inarg->offset = pos;
 300         inarg->size = count;
 301         inarg->flags = file->f_flags;
 302         req->in.h.opcode = opcode;
 303         req->in.h.nodeid = get_node_id(inode);
 304         req->in.numargs = 1;
 305         req->in.args[0].size = sizeof(struct fuse_read_in);
 306         req->in.args[0].value = inarg;
 307         req->out.argpages = 1;
 308         req->out.argvar = 1;
 309         req->out.numargs = 1;
 310         req->out.args[0].size = count;
 311 }
 312
 313 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 314                              struct inode *inode, loff_t pos, size_t count,
 315                              fl_owner_t owner)
 316 {
 317         struct fuse_conn *fc = get_fuse_conn(inode);
 318
 319         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
 320         if (owner != NULL) {
 321                 struct fuse_read_in *inarg = &req->misc.read_in;
 322
 323                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
 324                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 325         }
 326         request_send(fc, req);
 327         return req->out.args[0].size;
 328 }
 329
 330 static int fuse_readpage(struct file *file, struct page *page)
 331 {
 332         struct inode *inode = page->mapping->host;
 333         struct fuse_conn *fc = get_fuse_conn(inode);
 334         struct fuse_req *req;
 335         int err;
 336
 337         err = -EIO;
 338         if (is_bad_inode(inode))
 339                 goto out;
 340
 341         req = fuse_get_req(fc);
 342         err = PTR_ERR(req);
 343         if (IS_ERR(req))
 344                 goto out;
 345
 346         req->out.page_zeroing = 1;
 347         req->num_pages = 1;
 348         req->pages[0] = page;
 349         fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE,
 350                        NULL);
 351         err = req->out.h.error;
 352         fuse_put_request(fc, req);
 353         if (!err)
 354                 SetPageUptodate(page);
 355         fuse_invalidate_attr(inode); /* atime changed */
 356  out:
 357         unlock_page(page);
 358         return err;
 359 }
 360
 361 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 362 {
 363         int i;
 364
 365         fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
 366
 367         for (i = 0; i < req->num_pages; i++) {
 368                 struct page *page = req->pages[i];
 369                 if (!req->out.h.error)
 370                         SetPageUptodate(page);
 371                 else
 372                         SetPageError(page);
 373                 unlock_page(page);
 374         }
 375         if (req->ff)
 376                 fuse_file_put(req->ff);
 377         fuse_put_request(fc, req);
 378 }
 379
 380 static void fuse_send_readpages(struct fuse_req *req, struct file *file,
 381                                 struct inode *inode)
 382 {
 383         struct fuse_conn *fc = get_fuse_conn(inode);
 384         loff_t pos = page_offset(req->pages[0]);
 385         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 386         req->out.page_zeroing = 1;
 387         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
 388         if (fc->async_read) {
 389                 struct fuse_file *ff = file->private_data;
 390                 req->ff = fuse_file_get(ff);
 391                 req->end = fuse_readpages_end;
 392                 request_send_background(fc, req);
 393         } else {
 394                 request_send(fc, req);
 395                 fuse_readpages_end(fc, req);
 396         }
 397 }
 398
 399 struct fuse_fill_data {
 400         struct fuse_req *req;
 401         struct file *file;
 402         struct inode *inode;
 403 };
 404
 405 static int fuse_readpages_fill(void *_data, struct page *page)
 406 {
 407         struct fuse_fill_data *data = _data;
 408         struct fuse_req *req = data->req;
 409         struct inode *inode = data->inode;
 410         struct fuse_conn *fc = get_fuse_conn(inode);
 411
 412         if (req->num_pages &&
 413             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 414              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 415              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 416                 fuse_send_readpages(req, data->file, inode);
 417                 data->req = req = fuse_get_req(fc);
 418                 if (IS_ERR(req)) {
 419                         unlock_page(page);
 420                         return PTR_ERR(req);
 421                 }
 422         }
 423         req->pages[req->num_pages] = page;
 424         req->num_pages ++;
 425         return 0;
 426 }
 427
 428 static int fuse_readpages(struct file *file, struct address_space *mapping,
 429                           struct list_head *pages, unsigned nr_pages)
 430 {
 431         struct inode *inode = mapping->host;
 432         struct fuse_conn *fc = get_fuse_conn(inode);
 433         struct fuse_fill_data data;
 434         int err;
 435
 436         err = -EIO;
 437         if (is_bad_inode(inode))
 438                 goto out;
 439
 440         data.file = file;
 441         data.inode = inode;
 442         data.req = fuse_get_req(fc);
 443         err = PTR_ERR(data.req);
 444         if (IS_ERR(data.req))
 445                 goto out;
 446
 447         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 448         if (!err) {
 449                 if (data.req->num_pages)
 450                         fuse_send_readpages(data.req, file, inode);
 451                 else
 452                         fuse_put_request(fc, data.req);
 453         }
 454 out:
 455         return err;
 456 }
 457
 458 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 459                                   unsigned long nr_segs, loff_t pos)
 460 {
 461         struct inode *inode = iocb->ki_filp->f_mapping->host;
 462
 463         if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
 464                 int err;
 465                 /*
 466                  * If trying to read past EOF, make sure the i_size
 467                  * attribute is up-to-date.
 468                  */
 469                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 470                 if (err)
 471                         return err;
 472         }
 473
 474         return generic_file_aio_read(iocb, iov, nr_segs, pos);
 475 }
 476
 477 static void fuse_write_fill(struct fuse_req *req, struct file *file,
 478                             struct inode *inode, loff_t pos, size_t count,
 479                             int writepage)
 480 {
 481         struct fuse_conn *fc = get_fuse_conn(inode);
 482         struct fuse_file *ff = file->private_data;
 483         struct fuse_write_in *inarg = &req->misc.write.in;
 484         struct fuse_write_out *outarg = &req->misc.write.out;
 485
 486         memset(inarg, 0, sizeof(struct fuse_write_in));
 487         inarg->fh = ff->fh;
 488         inarg->offset = pos;
 489         inarg->size = count;
 490         inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
 491         inarg->flags = file->f_flags;
 492         req->in.h.opcode = FUSE_WRITE;
 493         req->in.h.nodeid = get_node_id(inode);
 494         req->in.argpages = 1;
 495         req->in.numargs = 2;
 496         if (fc->minor < 9)
 497                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 498         else
 499                 req->in.args[0].size = sizeof(struct fuse_write_in);
 500         req->in.args[0].value = inarg;
 501         req->in.args[1].size = count;
 502         req->out.numargs = 1;
 503         req->out.args[0].size = sizeof(struct fuse_write_out);
 504         req->out.args[0].value = outarg;
 505 }
 506
 507 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 508                               struct inode *inode, loff_t pos, size_t count,
 509                               fl_owner_t owner)
 510 {
 511         struct fuse_conn *fc = get_fuse_conn(inode);
 512         fuse_write_fill(req, file, inode, pos, count, 0);
 513         if (owner != NULL) {
 514                 struct fuse_write_in *inarg = &req->misc.write.in;
 515                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 516                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 517         }
 518         request_send(fc, req);
 519         return req->misc.write.out.size;
 520 }
 521
 522 static int fuse_write_begin(struct file *file, struct address_space *mapping,
 523                         loff_t pos, unsigned len, unsigned flags,
 524                         struct page **pagep, void **fsdata)
 525 {
 526         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 527
 528         *pagep = __grab_cache_page(mapping, index);
 529         if (!*pagep)
 530                 return -ENOMEM;
 531         return 0;
 532 }
 533
 534 static int fuse_buffered_write(struct file *file, struct inode *inode,
 535                                loff_t pos, unsigned count, struct page *page)
 536 {
 537         int err;
 538         size_t nres;
 539         struct fuse_conn *fc = get_fuse_conn(inode);
 540         struct fuse_inode *fi = get_fuse_inode(inode);
 541         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 542         struct fuse_req *req;
 543
 544         if (is_bad_inode(inode))
 545                 return -EIO;
 546
 547         req = fuse_get_req(fc);
 548         if (IS_ERR(req))
 549                 return PTR_ERR(req);
 550
 551         req->num_pages = 1;
 552         req->pages[0] = page;
 553         req->page_offset = offset;
 554         nres = fuse_send_write(req, file, inode, pos, count, NULL);
 555         err = req->out.h.error;
 556         fuse_put_request(fc, req);
 557         if (!err && !nres)
 558                 err = -EIO;
 559         if (!err) {
 560                 pos += nres;
 561                 spin_lock(&fc->lock);
 562                 fi->attr_version = ++fc->attr_version;
 563                 if (pos > inode->i_size)
 564                         i_size_write(inode, pos);
 565                 spin_unlock(&fc->lock);
 566
 567                 if (count == PAGE_CACHE_SIZE)
 568                         SetPageUptodate(page);
 569         }
 570         fuse_invalidate_attr(inode);
 571         return err ? err : nres;
 572 }
 573
 574 static int fuse_write_end(struct file *file, struct address_space *mapping,
 575                         loff_t pos, unsigned len, unsigned copied,
 576                         struct page *page, void *fsdata)
 577 {
 578         struct inode *inode = mapping->host;
 579         int res = 0;
 580
 581         if (copied)
 582                 res = fuse_buffered_write(file, inode, pos, copied, page);
 583
 584         unlock_page(page);
 585         page_cache_release(page);
 586         return res;
 587 }
 588
 589 static void fuse_release_user_pages(struct fuse_req *req, int write)
 590 {
 591         unsigned i;
 592
 593         for (i = 0; i < req->num_pages; i++) {
 594                 struct page *page = req->pages[i];
 595                 if (write)
 596                         set_page_dirty_lock(page);
 597                 put_page(page);
 598         }
 599 }
 600
 601 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
 602                                unsigned nbytes, int write)
 603 {
 604         unsigned long user_addr = (unsigned long) buf;
 605         unsigned offset = user_addr & ~PAGE_MASK;
 606         int npages;
 607
 608         /* This doesn't work with nfsd */
 609         if (!current->mm)
 610                 return -EPERM;
 611
 612         nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
 613         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 614         npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ);
 615         down_read(&current->mm->mmap_sem);
 616         npages = get_user_pages(current, current->mm, user_addr, npages, write,
 617                                 0, req->pages, NULL);
 618         up_read(&current->mm->mmap_sem);
 619         if (npages < 0)
 620                 return npages;
 621
 622         req->num_pages = npages;
 623         req->page_offset = offset;
 624         return 0;
 625 }
 626
 627 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 628                               size_t count, loff_t *ppos, int write)
 629 {
 630         struct inode *inode = file->f_path.dentry->d_inode;
 631         struct fuse_conn *fc = get_fuse_conn(inode);
 632         size_t nmax = write ? fc->max_write : fc->max_read;
 633         loff_t pos = *ppos;
 634         ssize_t res = 0;
 635         struct fuse_req *req;
 636
 637         if (is_bad_inode(inode))
 638                 return -EIO;
 639
 640         req = fuse_get_req(fc);
 641         if (IS_ERR(req))
 642                 return PTR_ERR(req);
 643
 644         while (count) {
 645                 size_t nres;
 646                 size_t nbytes = min(count, nmax);
 647                 int err = fuse_get_user_pages(req, buf, nbytes, !write);
 648                 if (err) {
 649                         res = err;
 650                         break;
 651                 }
 652                 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
 653                 nbytes = min(count, nbytes);
 654                 if (write)
 655                         nres = fuse_send_write(req, file, inode, pos, nbytes,
 656                                                current->files);
 657                 else
 658                         nres = fuse_send_read(req, file, inode, pos, nbytes,
 659                                               current->files);
 660                 fuse_release_user_pages(req, !write);
 661                 if (req->out.h.error) {
 662                         if (!res)
 663                                 res = req->out.h.error;
 664                         break;
 665                 } else if (nres > nbytes) {
 666                         res = -EIO;
 667                         break;
 668                 }
 669                 count -= nres;
 670                 res += nres;
 671                 pos += nres;
 672                 buf += nres;
 673                 if (nres != nbytes)
 674                         break;
 675                 if (count) {
 676                         fuse_put_request(fc, req);
 677                         req = fuse_get_req(fc);
 678                         if (IS_ERR(req))
 679                                 break;
 680                 }
 681         }
 682         fuse_put_request(fc, req);
 683         if (res > 0) {
 684                 if (write) {
 685                         spin_lock(&fc->lock);
 686                         if (pos > inode->i_size)
 687                                 i_size_write(inode, pos);
 688                         spin_unlock(&fc->lock);
 689                 }
 690                 *ppos = pos;
 691         }
 692         fuse_invalidate_attr(inode);
 693
 694         return res;
 695 }
 696
 697 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
 698                                      size_t count, loff_t *ppos)
 699 {
 700         return fuse_direct_io(file, buf, count, ppos, 0);
 701 }
 702
 703 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
 704                                  size_t count, loff_t *ppos)
 705 {
 706         struct inode *inode = file->f_path.dentry->d_inode;
 707         ssize_t res;
 708         /* Don't allow parallel writes to the same file */
 709         mutex_lock(&inode->i_mutex);
 710         res = generic_write_checks(file, ppos, &count, 0);
 711         if (!res)
 712                 res = fuse_direct_io(file, buf, count, ppos, 1);
 713         mutex_unlock(&inode->i_mutex);
 714         return res;
 715 }
 716
 717 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 718 {
 719         if ((vma->vm_flags & VM_SHARED)) {
 720                 if ((vma->vm_flags & VM_WRITE))
 721                         return -ENODEV;
 722                 else
 723                         vma->vm_flags &= ~VM_MAYWRITE;
 724         }
 725         return generic_file_mmap(file, vma);
 726 }
 727
 728 static int fuse_set_page_dirty(struct page *page)
 729 {
 730         printk("fuse_set_page_dirty: should not happen\n");
 731         dump_stack();
 732         return 0;
 733 }
 734
 735 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
 736                                   struct file_lock *fl)
 737 {
 738         switch (ffl->type) {
 739         case F_UNLCK:
 740                 break;
 741
 742         case F_RDLCK:
 743         case F_WRLCK:
 744                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
 745                     ffl->end < ffl->start)
 746                         return -EIO;
 747
 748                 fl->fl_start = ffl->start;
 749                 fl->fl_end = ffl->end;
 750                 fl->fl_pid = ffl->pid;
 751                 break;
 752
 753         default:
 754                 return -EIO;
 755         }
 756         fl->fl_type = ffl->type;
 757         return 0;
 758 }
 759
 760 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
 761                          const struct file_lock *fl, int opcode, pid_t pid,
 762                          int flock)
 763 {
 764         struct inode *inode = file->f_path.dentry->d_inode;
 765         struct fuse_conn *fc = get_fuse_conn(inode);
 766         struct fuse_file *ff = file->private_data;
 767         struct fuse_lk_in *arg = &req->misc.lk_in;
 768
 769         arg->fh = ff->fh;
 770         arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
 771         arg->lk.start = fl->fl_start;
 772         arg->lk.end = fl->fl_end;
 773         arg->lk.type = fl->fl_type;
 774         arg->lk.pid = pid;
 775         if (flock)
 776                 arg->lk_flags |= FUSE_LK_FLOCK;
 777         req->in.h.opcode = opcode;
 778         req->in.h.nodeid = get_node_id(inode);
 779         req->in.numargs = 1;
 780         req->in.args[0].size = sizeof(*arg);
 781         req->in.args[0].value = arg;
 782 }
 783
 784 static int fuse_getlk(struct file *file, struct file_lock *fl)
 785 {
 786         struct inode *inode = file->f_path.dentry->d_inode;
 787         struct fuse_conn *fc = get_fuse_conn(inode);
 788         struct fuse_req *req;
 789         struct fuse_lk_out outarg;
 790         int err;
 791
 792         req = fuse_get_req(fc);
 793         if (IS_ERR(req))
 794                 return PTR_ERR(req);
 795
 796         fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
 797         req->out.numargs = 1;
 798         req->out.args[0].size = sizeof(outarg);
 799         req->out.args[0].value = &outarg;
 800         request_send(fc, req);
 801         err = req->out.h.error;
 802         fuse_put_request(fc, req);
 803         if (!err)
 804                 err = convert_fuse_file_lock(&outarg.lk, fl);
 805
 806         return err;
 807 }
 808
 809 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
 810 {
 811         struct inode *inode = file->f_path.dentry->d_inode;
 812         struct fuse_conn *fc = get_fuse_conn(inode);
 813         struct fuse_req *req;
 814         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
 815         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
 816         int err;
 817
 818         /* Unlock on close is handled by the flush method */
 819         if (fl->fl_flags & FL_CLOSE)
 820                 return 0;
 821
 822         req = fuse_get_req(fc);
 823         if (IS_ERR(req))
 824                 return PTR_ERR(req);
 825
 826         fuse_lk_fill(req, file, fl, opcode, pid, flock);
 827         request_send(fc, req);
 828         err = req->out.h.error;
 829         /* locking is restartable */
 830         if (err == -EINTR)
 831                 err = -ERESTARTSYS;
 832         fuse_put_request(fc, req);
 833         return err;
 834 }
 835
 836 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
 837 {
 838         struct inode *inode = file->f_path.dentry->d_inode;
 839         struct fuse_conn *fc = get_fuse_conn(inode);
 840         int err;
 841
 842         if (cmd == F_GETLK) {
 843                 if (fc->no_lock) {
 844                         posix_test_lock(file, fl);
 845                         err = 0;
 846                 } else
 847                         err = fuse_getlk(file, fl);
 848         } else {
 849                 if (fc->no_lock)
 850                         err = posix_lock_file_wait(file, fl);
 851                 else
 852                         err = fuse_setlk(file, fl, 0);
 853         }
 854         return err;
 855 }
 856
 857 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
 858 {
 859         struct inode *inode = file->f_path.dentry->d_inode;
 860         struct fuse_conn *fc = get_fuse_conn(inode);
 861         int err;
 862
 863         if (fc->no_lock) {
 864                 err = flock_lock_file_wait(file, fl);
 865         } else {
 866                 /* emulate flock with POSIX locks */
 867                 fl->fl_owner = (fl_owner_t) file;
 868                 err = fuse_setlk(file, fl, 1);
 869         }
 870
 871         return err;
 872 }
 873
 874 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
 875 {
 876         struct inode *inode = mapping->host;
 877         struct fuse_conn *fc = get_fuse_conn(inode);
 878         struct fuse_req *req;
 879         struct fuse_bmap_in inarg;
 880         struct fuse_bmap_out outarg;
 881         int err;
 882
 883         if (!inode->i_sb->s_bdev || fc->no_bmap)
 884                 return 0;
 885
 886         req = fuse_get_req(fc);
 887         if (IS_ERR(req))
 888                 return 0;
 889
 890         memset(&inarg, 0, sizeof(inarg));
 891         inarg.block = block;
 892         inarg.blocksize = inode->i_sb->s_blocksize;
 893         req->in.h.opcode = FUSE_BMAP;
 894         req->in.h.nodeid = get_node_id(inode);
 895         req->in.numargs = 1;
 896         req->in.args[0].size = sizeof(inarg);
 897         req->in.args[0].value = &inarg;
 898         req->out.numargs = 1;
 899         req->out.args[0].size = sizeof(outarg);
 900         req->out.args[0].value = &outarg;
 901         request_send(fc, req);
 902         err = req->out.h.error;
 903         fuse_put_request(fc, req);
 904         if (err == -ENOSYS)
 905                 fc->no_bmap = 1;
 906
 907         return err ? 0 : outarg.block;
 908 }
 909
 910 static const struct file_operations fuse_file_operations = {
 911         .llseek         = generic_file_llseek,
 912         .read           = do_sync_read,
 913         .aio_read       = fuse_file_aio_read,
 914         .write          = do_sync_write,
 915         .aio_write      = generic_file_aio_write,
 916         .mmap           = fuse_file_mmap,
 917         .open           = fuse_open,
 918         .flush          = fuse_flush,
 919         .release        = fuse_release,
 920         .fsync          = fuse_fsync,
 921         .lock           = fuse_file_lock,
 922         .flock          = fuse_file_flock,
 923         .splice_read    = generic_file_splice_read,
 924 };
 925
 926 static const struct file_operations fuse_direct_io_file_operations = {
 927         .llseek         = generic_file_llseek,
 928         .read           = fuse_direct_read,
 929         .write          = fuse_direct_write,
 930         .open           = fuse_open,
 931         .flush          = fuse_flush,
 932         .release        = fuse_release,
 933         .fsync          = fuse_fsync,
 934         .lock           = fuse_file_lock,
 935         .flock          = fuse_file_flock,
 936         /* no mmap and splice_read */
 937 };
 938
 939 static const struct address_space_operations fuse_file_aops  = {
 940         .readpage       = fuse_readpage,
 941         .write_begin    = fuse_write_begin,
 942         .write_end      = fuse_write_end,
 943         .readpages      = fuse_readpages,
 944         .set_page_dirty = fuse_set_page_dirty,
 945         .bmap           = fuse_bmap,
 946 };
 947
 948 void fuse_init_file_inode(struct inode *inode)
 949 {
 950         inode->i_fop = &fuse_file_operations;
 951         inode->i_data.a_ops = &fuse_file_aops;
 952 }