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 fuse_file *ff,
 293                     struct inode *inode, loff_t pos, size_t count, int opcode)
 294 {
 295         struct fuse_read_in *inarg = &req->misc.read_in;
 296
 297         inarg->fh = ff->fh;
 298         inarg->offset = pos;
 299         inarg->size = count;
 300         req->in.h.opcode = opcode;
 301         req->in.h.nodeid = get_node_id(inode);
 302         req->in.numargs = 1;
 303         req->in.args[0].size = sizeof(struct fuse_read_in);
 304         req->in.args[0].value = inarg;
 305         req->out.argpages = 1;
 306         req->out.argvar = 1;
 307         req->out.numargs = 1;
 308         req->out.args[0].size = count;
 309 }
 310
 311 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 312                              struct inode *inode, loff_t pos, size_t count,
 313                              fl_owner_t owner)
 314 {
 315         struct fuse_conn *fc = get_fuse_conn(inode);
 316         struct fuse_file *ff = file->private_data;
 317
 318         fuse_read_fill(req, ff, inode, pos, count, FUSE_READ);
 319         if (owner != NULL) {
 320                 struct fuse_read_in *inarg = &req->misc.read_in;
 321
 322                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
 323                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 324         }
 325         request_send(fc, req);
 326         return req->out.args[0].size;
 327 }
 328
 329 static int fuse_readpage(struct file *file, struct page *page)
 330 {
 331         struct inode *inode = page->mapping->host;
 332         struct fuse_conn *fc = get_fuse_conn(inode);
 333         struct fuse_req *req;
 334         int err;
 335
 336         err = -EIO;
 337         if (is_bad_inode(inode))
 338                 goto out;
 339
 340         req = fuse_get_req(fc);
 341         err = PTR_ERR(req);
 342         if (IS_ERR(req))
 343                 goto out;
 344
 345         req->out.page_zeroing = 1;
 346         req->num_pages = 1;
 347         req->pages[0] = page;
 348         fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE,
 349                        NULL);
 350         err = req->out.h.error;
 351         fuse_put_request(fc, req);
 352         if (!err)
 353                 SetPageUptodate(page);
 354         fuse_invalidate_attr(inode); /* atime changed */
 355  out:
 356         unlock_page(page);
 357         return err;
 358 }
 359
 360 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 361 {
 362         int i;
 363
 364         fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
 365
 366         for (i = 0; i < req->num_pages; i++) {
 367                 struct page *page = req->pages[i];
 368                 if (!req->out.h.error)
 369                         SetPageUptodate(page);
 370                 else
 371                         SetPageError(page);
 372                 unlock_page(page);
 373         }
 374         if (req->ff)
 375                 fuse_file_put(req->ff);
 376         fuse_put_request(fc, req);
 377 }
 378
 379 static void fuse_send_readpages(struct fuse_req *req, struct fuse_file *ff,
 380                                 struct inode *inode)
 381 {
 382         struct fuse_conn *fc = get_fuse_conn(inode);
 383         loff_t pos = page_offset(req->pages[0]);
 384         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 385         req->out.page_zeroing = 1;
 386         fuse_read_fill(req, ff, inode, pos, count, FUSE_READ);
 387         if (fc->async_read) {
 388                 req->ff = fuse_file_get(ff);
 389                 req->end = fuse_readpages_end;
 390                 request_send_background(fc, req);
 391         } else {
 392                 request_send(fc, req);
 393                 fuse_readpages_end(fc, req);
 394         }
 395 }
 396
 397 struct fuse_fill_data {
 398         struct fuse_req *req;
 399         struct fuse_file *ff;
 400         struct inode *inode;
 401 };
 402
 403 static int fuse_readpages_fill(void *_data, struct page *page)
 404 {
 405         struct fuse_fill_data *data = _data;
 406         struct fuse_req *req = data->req;
 407         struct inode *inode = data->inode;
 408         struct fuse_conn *fc = get_fuse_conn(inode);
 409
 410         if (req->num_pages &&
 411             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 412              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 413              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 414                 fuse_send_readpages(req, data->ff, inode);
 415                 data->req = req = fuse_get_req(fc);
 416                 if (IS_ERR(req)) {
 417                         unlock_page(page);
 418                         return PTR_ERR(req);
 419                 }
 420         }
 421         req->pages[req->num_pages] = page;
 422         req->num_pages ++;
 423         return 0;
 424 }
 425
 426 static int fuse_readpages(struct file *file, struct address_space *mapping,
 427                           struct list_head *pages, unsigned nr_pages)
 428 {
 429         struct inode *inode = mapping->host;
 430         struct fuse_conn *fc = get_fuse_conn(inode);
 431         struct fuse_fill_data data;
 432         int err;
 433
 434         err = -EIO;
 435         if (is_bad_inode(inode))
 436                 goto out;
 437
 438         data.ff = file->private_data;
 439         data.inode = inode;
 440         data.req = fuse_get_req(fc);
 441         err = PTR_ERR(data.req);
 442         if (IS_ERR(data.req))
 443                 goto out;
 444
 445         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 446         if (!err) {
 447                 if (data.req->num_pages)
 448                         fuse_send_readpages(data.req, data.ff, inode);
 449                 else
 450                         fuse_put_request(fc, data.req);
 451         }
 452 out:
 453         return err;
 454 }
 455
 456 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 457                                   unsigned long nr_segs, loff_t pos)
 458 {
 459         struct inode *inode = iocb->ki_filp->f_mapping->host;
 460
 461         if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
 462                 int err;
 463                 /*
 464                  * If trying to read past EOF, make sure the i_size
 465                  * attribute is up-to-date.
 466                  */
 467                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 468                 if (err)
 469                         return err;
 470         }
 471
 472         return generic_file_aio_read(iocb, iov, nr_segs, pos);
 473 }
 474
 475 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
 476                             struct inode *inode, loff_t pos, size_t count,
 477                             int writepage)
 478 {
 479         struct fuse_conn *fc = get_fuse_conn(inode);
 480         struct fuse_write_in *inarg = &req->misc.write.in;
 481         struct fuse_write_out *outarg = &req->misc.write.out;
 482
 483         memset(inarg, 0, sizeof(struct fuse_write_in));
 484         inarg->fh = ff->fh;
 485         inarg->offset = pos;
 486         inarg->size = count;
 487         inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
 488         req->in.h.opcode = FUSE_WRITE;
 489         req->in.h.nodeid = get_node_id(inode);
 490         req->in.argpages = 1;
 491         req->in.numargs = 2;
 492         if (fc->minor < 9)
 493                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 494         else
 495                 req->in.args[0].size = sizeof(struct fuse_write_in);
 496         req->in.args[0].value = inarg;
 497         req->in.args[1].size = count;
 498         req->out.numargs = 1;
 499         req->out.args[0].size = sizeof(struct fuse_write_out);
 500         req->out.args[0].value = outarg;
 501 }
 502
 503 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 504                               struct inode *inode, loff_t pos, size_t count,
 505                               fl_owner_t owner)
 506 {
 507         struct fuse_conn *fc = get_fuse_conn(inode);
 508         fuse_write_fill(req, file->private_data, inode, pos, count, 0);
 509         if (owner != NULL) {
 510                 struct fuse_write_in *inarg = &req->misc.write.in;
 511                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 512                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 513         }
 514         request_send(fc, req);
 515         return req->misc.write.out.size;
 516 }
 517
 518 static int fuse_write_begin(struct file *file, struct address_space *mapping,
 519                         loff_t pos, unsigned len, unsigned flags,
 520                         struct page **pagep, void **fsdata)
 521 {
 522         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 523
 524         *pagep = __grab_cache_page(mapping, index);
 525         if (!*pagep)
 526                 return -ENOMEM;
 527         return 0;
 528 }
 529
 530 static int fuse_buffered_write(struct file *file, struct inode *inode,
 531                                loff_t pos, unsigned count, struct page *page)
 532 {
 533         int err;
 534         size_t nres;
 535         struct fuse_conn *fc = get_fuse_conn(inode);
 536         struct fuse_inode *fi = get_fuse_inode(inode);
 537         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 538         struct fuse_req *req;
 539
 540         if (is_bad_inode(inode))
 541                 return -EIO;
 542
 543         req = fuse_get_req(fc);
 544         if (IS_ERR(req))
 545                 return PTR_ERR(req);
 546
 547         req->num_pages = 1;
 548         req->pages[0] = page;
 549         req->page_offset = offset;
 550         nres = fuse_send_write(req, file, inode, pos, count, NULL);
 551         err = req->out.h.error;
 552         fuse_put_request(fc, req);
 553         if (!err && !nres)
 554                 err = -EIO;
 555         if (!err) {
 556                 pos += nres;
 557                 spin_lock(&fc->lock);
 558                 fi->attr_version = ++fc->attr_version;
 559                 if (pos > inode->i_size)
 560                         i_size_write(inode, pos);
 561                 spin_unlock(&fc->lock);
 562
 563                 if (count == PAGE_CACHE_SIZE)
 564                         SetPageUptodate(page);
 565         }
 566         fuse_invalidate_attr(inode);
 567         return err ? err : nres;
 568 }
 569
 570 static int fuse_write_end(struct file *file, struct address_space *mapping,
 571                         loff_t pos, unsigned len, unsigned copied,
 572                         struct page *page, void *fsdata)
 573 {
 574         struct inode *inode = mapping->host;
 575         int res = 0;
 576
 577         if (copied)
 578                 res = fuse_buffered_write(file, inode, pos, copied, page);
 579
 580         unlock_page(page);
 581         page_cache_release(page);
 582         return res;
 583 }
 584
 585 static void fuse_release_user_pages(struct fuse_req *req, int write)
 586 {
 587         unsigned i;
 588
 589         for (i = 0; i < req->num_pages; i++) {
 590                 struct page *page = req->pages[i];
 591                 if (write)
 592                         set_page_dirty_lock(page);
 593                 put_page(page);
 594         }
 595 }
 596
 597 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
 598                                unsigned nbytes, int write)
 599 {
 600         unsigned long user_addr = (unsigned long) buf;
 601         unsigned offset = user_addr & ~PAGE_MASK;
 602         int npages;
 603
 604         /* This doesn't work with nfsd */
 605         if (!current->mm)
 606                 return -EPERM;
 607
 608         nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
 609         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 610         npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ);
 611         down_read(&current->mm->mmap_sem);
 612         npages = get_user_pages(current, current->mm, user_addr, npages, write,
 613                                 0, req->pages, NULL);
 614         up_read(&current->mm->mmap_sem);
 615         if (npages < 0)
 616                 return npages;
 617
 618         req->num_pages = npages;
 619         req->page_offset = offset;
 620         return 0;
 621 }
 622
 623 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 624                               size_t count, loff_t *ppos, int write)
 625 {
 626         struct inode *inode = file->f_path.dentry->d_inode;
 627         struct fuse_conn *fc = get_fuse_conn(inode);
 628         size_t nmax = write ? fc->max_write : fc->max_read;
 629         loff_t pos = *ppos;
 630         ssize_t res = 0;
 631         struct fuse_req *req;
 632
 633         if (is_bad_inode(inode))
 634                 return -EIO;
 635
 636         req = fuse_get_req(fc);
 637         if (IS_ERR(req))
 638                 return PTR_ERR(req);
 639
 640         while (count) {
 641                 size_t nres;
 642                 size_t nbytes = min(count, nmax);
 643                 int err = fuse_get_user_pages(req, buf, nbytes, !write);
 644                 if (err) {
 645                         res = err;
 646                         break;
 647                 }
 648                 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
 649                 nbytes = min(count, nbytes);
 650                 if (write)
 651                         nres = fuse_send_write(req, file, inode, pos, nbytes,
 652                                                current->files);
 653                 else
 654                         nres = fuse_send_read(req, file, inode, pos, nbytes,
 655                                               current->files);
 656                 fuse_release_user_pages(req, !write);
 657                 if (req->out.h.error) {
 658                         if (!res)
 659                                 res = req->out.h.error;
 660                         break;
 661                 } else if (nres > nbytes) {
 662                         res = -EIO;
 663                         break;
 664                 }
 665                 count -= nres;
 666                 res += nres;
 667                 pos += nres;
 668                 buf += nres;
 669                 if (nres != nbytes)
 670                         break;
 671                 if (count) {
 672                         fuse_put_request(fc, req);
 673                         req = fuse_get_req(fc);
 674                         if (IS_ERR(req))
 675                                 break;
 676                 }
 677         }
 678         fuse_put_request(fc, req);
 679         if (res > 0) {
 680                 if (write) {
 681                         spin_lock(&fc->lock);
 682                         if (pos > inode->i_size)
 683                                 i_size_write(inode, pos);
 684                         spin_unlock(&fc->lock);
 685                 }
 686                 *ppos = pos;
 687         }
 688         fuse_invalidate_attr(inode);
 689
 690         return res;
 691 }
 692
 693 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
 694                                      size_t count, loff_t *ppos)
 695 {
 696         return fuse_direct_io(file, buf, count, ppos, 0);
 697 }
 698
 699 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
 700                                  size_t count, loff_t *ppos)
 701 {
 702         struct inode *inode = file->f_path.dentry->d_inode;
 703         ssize_t res;
 704         /* Don't allow parallel writes to the same file */
 705         mutex_lock(&inode->i_mutex);
 706         res = generic_write_checks(file, ppos, &count, 0);
 707         if (!res)
 708                 res = fuse_direct_io(file, buf, count, ppos, 1);
 709         mutex_unlock(&inode->i_mutex);
 710         return res;
 711 }
 712
 713 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 714 {
 715         if ((vma->vm_flags & VM_SHARED)) {
 716                 if ((vma->vm_flags & VM_WRITE))
 717                         return -ENODEV;
 718                 else
 719                         vma->vm_flags &= ~VM_MAYWRITE;
 720         }
 721         return generic_file_mmap(file, vma);
 722 }
 723
 724 static int fuse_set_page_dirty(struct page *page)
 725 {
 726         printk("fuse_set_page_dirty: should not happen\n");
 727         dump_stack();
 728         return 0;
 729 }
 730
 731 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
 732                                   struct file_lock *fl)
 733 {
 734         switch (ffl->type) {
 735         case F_UNLCK:
 736                 break;
 737
 738         case F_RDLCK:
 739         case F_WRLCK:
 740                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
 741                     ffl->end < ffl->start)
 742                         return -EIO;
 743
 744                 fl->fl_start = ffl->start;
 745                 fl->fl_end = ffl->end;
 746                 fl->fl_pid = ffl->pid;
 747                 break;
 748
 749         default:
 750                 return -EIO;
 751         }
 752         fl->fl_type = ffl->type;
 753         return 0;
 754 }
 755
 756 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
 757                          const struct file_lock *fl, int opcode, pid_t pid,
 758                          int flock)
 759 {
 760         struct inode *inode = file->f_path.dentry->d_inode;
 761         struct fuse_conn *fc = get_fuse_conn(inode);
 762         struct fuse_file *ff = file->private_data;
 763         struct fuse_lk_in *arg = &req->misc.lk_in;
 764
 765         arg->fh = ff->fh;
 766         arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
 767         arg->lk.start = fl->fl_start;
 768         arg->lk.end = fl->fl_end;
 769         arg->lk.type = fl->fl_type;
 770         arg->lk.pid = pid;
 771         if (flock)
 772                 arg->lk_flags |= FUSE_LK_FLOCK;
 773         req->in.h.opcode = opcode;
 774         req->in.h.nodeid = get_node_id(inode);
 775         req->in.numargs = 1;
 776         req->in.args[0].size = sizeof(*arg);
 777         req->in.args[0].value = arg;
 778 }
 779
 780 static int fuse_getlk(struct file *file, struct file_lock *fl)
 781 {
 782         struct inode *inode = file->f_path.dentry->d_inode;
 783         struct fuse_conn *fc = get_fuse_conn(inode);
 784         struct fuse_req *req;
 785         struct fuse_lk_out outarg;
 786         int err;
 787
 788         req = fuse_get_req(fc);
 789         if (IS_ERR(req))
 790                 return PTR_ERR(req);
 791
 792         fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
 793         req->out.numargs = 1;
 794         req->out.args[0].size = sizeof(outarg);
 795         req->out.args[0].value = &outarg;
 796         request_send(fc, req);
 797         err = req->out.h.error;
 798         fuse_put_request(fc, req);
 799         if (!err)
 800                 err = convert_fuse_file_lock(&outarg.lk, fl);
 801
 802         return err;
 803 }
 804
 805 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
 806 {
 807         struct inode *inode = file->f_path.dentry->d_inode;
 808         struct fuse_conn *fc = get_fuse_conn(inode);
 809         struct fuse_req *req;
 810         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
 811         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
 812         int err;
 813
 814         /* Unlock on close is handled by the flush method */
 815         if (fl->fl_flags & FL_CLOSE)
 816                 return 0;
 817
 818         req = fuse_get_req(fc);
 819         if (IS_ERR(req))
 820                 return PTR_ERR(req);
 821
 822         fuse_lk_fill(req, file, fl, opcode, pid, flock);
 823         request_send(fc, req);
 824         err = req->out.h.error;
 825         /* locking is restartable */
 826         if (err == -EINTR)
 827                 err = -ERESTARTSYS;
 828         fuse_put_request(fc, req);
 829         return err;
 830 }
 831
 832 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
 833 {
 834         struct inode *inode = file->f_path.dentry->d_inode;
 835         struct fuse_conn *fc = get_fuse_conn(inode);
 836         int err;
 837
 838         if (cmd == F_GETLK) {
 839                 if (fc->no_lock) {
 840                         posix_test_lock(file, fl);
 841                         err = 0;
 842                 } else
 843                         err = fuse_getlk(file, fl);
 844         } else {
 845                 if (fc->no_lock)
 846                         err = posix_lock_file_wait(file, fl);
 847                 else
 848                         err = fuse_setlk(file, fl, 0);
 849         }
 850         return err;
 851 }
 852
 853 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
 854 {
 855         struct inode *inode = file->f_path.dentry->d_inode;
 856         struct fuse_conn *fc = get_fuse_conn(inode);
 857         int err;
 858
 859         if (fc->no_lock) {
 860                 err = flock_lock_file_wait(file, fl);
 861         } else {
 862                 /* emulate flock with POSIX locks */
 863                 fl->fl_owner = (fl_owner_t) file;
 864                 err = fuse_setlk(file, fl, 1);
 865         }
 866
 867         return err;
 868 }
 869
 870 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
 871 {
 872         struct inode *inode = mapping->host;
 873         struct fuse_conn *fc = get_fuse_conn(inode);
 874         struct fuse_req *req;
 875         struct fuse_bmap_in inarg;
 876         struct fuse_bmap_out outarg;
 877         int err;
 878
 879         if (!inode->i_sb->s_bdev || fc->no_bmap)
 880                 return 0;
 881
 882         req = fuse_get_req(fc);
 883         if (IS_ERR(req))
 884                 return 0;
 885
 886         memset(&inarg, 0, sizeof(inarg));
 887         inarg.block = block;
 888         inarg.blocksize = inode->i_sb->s_blocksize;
 889         req->in.h.opcode = FUSE_BMAP;
 890         req->in.h.nodeid = get_node_id(inode);
 891         req->in.numargs = 1;
 892         req->in.args[0].size = sizeof(inarg);
 893         req->in.args[0].value = &inarg;
 894         req->out.numargs = 1;
 895         req->out.args[0].size = sizeof(outarg);
 896         req->out.args[0].value = &outarg;
 897         request_send(fc, req);
 898         err = req->out.h.error;
 899         fuse_put_request(fc, req);
 900         if (err == -ENOSYS)
 901                 fc->no_bmap = 1;
 902
 903         return err ? 0 : outarg.block;
 904 }
 905
 906 static const struct file_operations fuse_file_operations = {
 907         .llseek         = generic_file_llseek,
 908         .read           = do_sync_read,
 909         .aio_read       = fuse_file_aio_read,
 910         .write          = do_sync_write,
 911         .aio_write      = generic_file_aio_write,
 912         .mmap           = fuse_file_mmap,
 913         .open           = fuse_open,
 914         .flush          = fuse_flush,
 915         .release        = fuse_release,
 916         .fsync          = fuse_fsync,
 917         .lock           = fuse_file_lock,
 918         .flock          = fuse_file_flock,
 919         .splice_read    = generic_file_splice_read,
 920 };
 921
 922 static const struct file_operations fuse_direct_io_file_operations = {
 923         .llseek         = generic_file_llseek,
 924         .read           = fuse_direct_read,
 925         .write          = fuse_direct_write,
 926         .open           = fuse_open,
 927         .flush          = fuse_flush,
 928         .release        = fuse_release,
 929         .fsync          = fuse_fsync,
 930         .lock           = fuse_file_lock,
 931         .flock          = fuse_file_flock,
 932         /* no mmap and splice_read */
 933 };
 934
 935 static const struct address_space_operations fuse_file_aops  = {
 936         .readpage       = fuse_readpage,
 937         .write_begin    = fuse_write_begin,
 938         .write_end      = fuse_write_end,
 939         .readpages      = fuse_readpages,
 940         .set_page_dirty = fuse_set_page_dirty,
 941         .bmap           = fuse_bmap,
 942 };
 943
 944 void fuse_init_file_inode(struct inode *inode)
 945 {
 946         inode->i_fop = &fuse_file_operations;
 947         inode->i_data.a_ops = &fuse_file_aops;
 948 }