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->misc.release.dentry);
  81         mntput(req->misc.release.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 inode *inode = req->misc.release.dentry->d_inode;
  90                 struct fuse_conn *fc = get_fuse_conn(inode);
  91                 req->end = fuse_release_end;
  92                 request_send_background(fc, req);
  93                 kfree(ff);
  94         }
  95 }
  96
  97 void fuse_finish_open(struct inode *inode, struct file *file,
  98                       struct fuse_file *ff, struct fuse_open_out *outarg)
  99 {
 100         if (outarg->open_flags & FOPEN_DIRECT_IO)
 101                 file->f_op = &fuse_direct_io_file_operations;
 102         if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
 103                 invalidate_inode_pages2(inode->i_mapping);
 104         ff->fh = outarg->fh;
 105         file->private_data = fuse_file_get(ff);
 106 }
 107
 108 int fuse_open_common(struct inode *inode, struct file *file, int isdir)
 109 {
 110         struct fuse_open_out outarg;
 111         struct fuse_file *ff;
 112         int err;
 113
 114         /* VFS checks this, but only _after_ ->open() */
 115         if (file->f_flags & O_DIRECT)
 116                 return -EINVAL;
 117
 118         err = generic_file_open(inode, file);
 119         if (err)
 120                 return err;
 121
 122         ff = fuse_file_alloc();
 123         if (!ff)
 124                 return -ENOMEM;
 125
 126         err = fuse_send_open(inode, file, isdir, &outarg);
 127         if (err)
 128                 fuse_file_free(ff);
 129         else {
 130                 if (isdir)
 131                         outarg.open_flags &= ~FOPEN_DIRECT_IO;
 132                 fuse_finish_open(inode, file, ff, &outarg);
 133         }
 134
 135         return err;
 136 }
 137
 138 void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode)
 139 {
 140         struct fuse_req *req = ff->reserved_req;
 141         struct fuse_release_in *inarg = &req->misc.release.in;
 142
 143         inarg->fh = ff->fh;
 144         inarg->flags = flags;
 145         req->in.h.opcode = opcode;
 146         req->in.h.nodeid = nodeid;
 147         req->in.numargs = 1;
 148         req->in.args[0].size = sizeof(struct fuse_release_in);
 149         req->in.args[0].value = inarg;
 150 }
 151
 152 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
 153 {
 154         struct fuse_file *ff = file->private_data;
 155         if (ff) {
 156                 struct fuse_conn *fc = get_fuse_conn(inode);
 157                 struct fuse_req *req = ff->reserved_req;
 158
 159                 fuse_release_fill(ff, get_node_id(inode), file->f_flags,
 160                                   isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
 161
 162                 /* Hold vfsmount and dentry until release is finished */
 163                 req->misc.release.vfsmount = mntget(file->f_path.mnt);
 164                 req->misc.release.dentry = dget(file->f_path.dentry);
 165
 166                 spin_lock(&fc->lock);
 167                 list_del(&ff->write_entry);
 168                 spin_unlock(&fc->lock);
 169                 /*
 170                  * Normally this will send the RELEASE request,
 171                  * however if some asynchronous READ or WRITE requests
 172                  * are outstanding, the sending will be delayed
 173                  */
 174                 fuse_file_put(ff);
 175         }
 176
 177         /* Return value is ignored by VFS */
 178         return 0;
 179 }
 180
 181 static int fuse_open(struct inode *inode, struct file *file)
 182 {
 183         return fuse_open_common(inode, file, 0);
 184 }
 185
 186 static int fuse_release(struct inode *inode, struct file *file)
 187 {
 188         return fuse_release_common(inode, file, 0);
 189 }
 190
 191 /*
 192  * Scramble the ID space with XTEA, so that the value of the files_struct
 193  * pointer is not exposed to userspace.
 194  */
 195 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
 196 {
 197         u32 *k = fc->scramble_key;
 198         u64 v = (unsigned long) id;
 199         u32 v0 = v;
 200         u32 v1 = v >> 32;
 201         u32 sum = 0;
 202         int i;
 203
 204         for (i = 0; i < 32; i++) {
 205                 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
 206                 sum += 0x9E3779B9;
 207                 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
 208         }
 209
 210         return (u64) v0 + ((u64) v1 << 32);
 211 }
 212
 213 static int fuse_flush(struct file *file, fl_owner_t id)
 214 {
 215         struct inode *inode = file->f_path.dentry->d_inode;
 216         struct fuse_conn *fc = get_fuse_conn(inode);
 217         struct fuse_file *ff = file->private_data;
 218         struct fuse_req *req;
 219         struct fuse_flush_in inarg;
 220         int err;
 221
 222         if (is_bad_inode(inode))
 223                 return -EIO;
 224
 225         if (fc->no_flush)
 226                 return 0;
 227
 228         req = fuse_get_req_nofail(fc, file);
 229         memset(&inarg, 0, sizeof(inarg));
 230         inarg.fh = ff->fh;
 231         inarg.lock_owner = fuse_lock_owner_id(fc, id);
 232         req->in.h.opcode = FUSE_FLUSH;
 233         req->in.h.nodeid = get_node_id(inode);
 234         req->in.numargs = 1;
 235         req->in.args[0].size = sizeof(inarg);
 236         req->in.args[0].value = &inarg;
 237         req->force = 1;
 238         request_send(fc, req);
 239         err = req->out.h.error;
 240         fuse_put_request(fc, req);
 241         if (err == -ENOSYS) {
 242                 fc->no_flush = 1;
 243                 err = 0;
 244         }
 245         return err;
 246 }
 247
 248 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
 249                       int isdir)
 250 {
 251         struct inode *inode = de->d_inode;
 252         struct fuse_conn *fc = get_fuse_conn(inode);
 253         struct fuse_file *ff = file->private_data;
 254         struct fuse_req *req;
 255         struct fuse_fsync_in inarg;
 256         int err;
 257
 258         if (is_bad_inode(inode))
 259                 return -EIO;
 260
 261         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
 262                 return 0;
 263
 264         req = fuse_get_req(fc);
 265         if (IS_ERR(req))
 266                 return PTR_ERR(req);
 267
 268         memset(&inarg, 0, sizeof(inarg));
 269         inarg.fh = ff->fh;
 270         inarg.fsync_flags = datasync ? 1 : 0;
 271         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
 272         req->in.h.nodeid = get_node_id(inode);
 273         req->in.numargs = 1;
 274         req->in.args[0].size = sizeof(inarg);
 275         req->in.args[0].value = &inarg;
 276         request_send(fc, req);
 277         err = req->out.h.error;
 278         fuse_put_request(fc, req);
 279         if (err == -ENOSYS) {
 280                 if (isdir)
 281                         fc->no_fsyncdir = 1;
 282                 else
 283                         fc->no_fsync = 1;
 284                 err = 0;
 285         }
 286         return err;
 287 }
 288
 289 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
 290 {
 291         return fuse_fsync_common(file, de, datasync, 0);
 292 }
 293
 294 void fuse_read_fill(struct fuse_req *req, struct file *file,
 295                     struct inode *inode, loff_t pos, size_t count, int opcode)
 296 {
 297         struct fuse_read_in *inarg = &req->misc.read_in;
 298         struct fuse_file *ff = file->private_data;
 299
 300         inarg->fh = ff->fh;
 301         inarg->offset = pos;
 302         inarg->size = count;
 303         inarg->flags = file->f_flags;
 304         req->in.h.opcode = opcode;
 305         req->in.h.nodeid = get_node_id(inode);
 306         req->in.numargs = 1;
 307         req->in.args[0].size = sizeof(struct fuse_read_in);
 308         req->in.args[0].value = inarg;
 309         req->out.argpages = 1;
 310         req->out.argvar = 1;
 311         req->out.numargs = 1;
 312         req->out.args[0].size = count;
 313 }
 314
 315 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
 316                              struct inode *inode, loff_t pos, size_t count,
 317                              fl_owner_t owner)
 318 {
 319         struct fuse_conn *fc = get_fuse_conn(inode);
 320
 321         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
 322         if (owner != NULL) {
 323                 struct fuse_read_in *inarg = &req->misc.read_in;
 324
 325                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
 326                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 327         }
 328         request_send(fc, req);
 329         return req->out.args[0].size;
 330 }
 331
 332 static int fuse_readpage(struct file *file, struct page *page)
 333 {
 334         struct inode *inode = page->mapping->host;
 335         struct fuse_conn *fc = get_fuse_conn(inode);
 336         struct fuse_req *req;
 337         int err;
 338
 339         err = -EIO;
 340         if (is_bad_inode(inode))
 341                 goto out;
 342
 343         req = fuse_get_req(fc);
 344         err = PTR_ERR(req);
 345         if (IS_ERR(req))
 346                 goto out;
 347
 348         req->out.page_zeroing = 1;
 349         req->num_pages = 1;
 350         req->pages[0] = page;
 351         fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE,
 352                        NULL);
 353         err = req->out.h.error;
 354         fuse_put_request(fc, req);
 355         if (!err)
 356                 SetPageUptodate(page);
 357         fuse_invalidate_attr(inode); /* atime changed */
 358  out:
 359         unlock_page(page);
 360         return err;
 361 }
 362
 363 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 364 {
 365         int i;
 366
 367         fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
 368
 369         for (i = 0; i < req->num_pages; i++) {
 370                 struct page *page = req->pages[i];
 371                 if (!req->out.h.error)
 372                         SetPageUptodate(page);
 373                 else
 374                         SetPageError(page);
 375                 unlock_page(page);
 376         }
 377         if (req->ff)
 378                 fuse_file_put(req->ff);
 379         fuse_put_request(fc, req);
 380 }
 381
 382 static void fuse_send_readpages(struct fuse_req *req, struct file *file,
 383                                 struct inode *inode)
 384 {
 385         struct fuse_conn *fc = get_fuse_conn(inode);
 386         loff_t pos = page_offset(req->pages[0]);
 387         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
 388         req->out.page_zeroing = 1;
 389         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
 390         if (fc->async_read) {
 391                 struct fuse_file *ff = file->private_data;
 392                 req->ff = fuse_file_get(ff);
 393                 req->end = fuse_readpages_end;
 394                 request_send_background(fc, req);
 395         } else {
 396                 request_send(fc, req);
 397                 fuse_readpages_end(fc, req);
 398         }
 399 }
 400
 401 struct fuse_fill_data {
 402         struct fuse_req *req;
 403         struct file *file;
 404         struct inode *inode;
 405 };
 406
 407 static int fuse_readpages_fill(void *_data, struct page *page)
 408 {
 409         struct fuse_fill_data *data = _data;
 410         struct fuse_req *req = data->req;
 411         struct inode *inode = data->inode;
 412         struct fuse_conn *fc = get_fuse_conn(inode);
 413
 414         if (req->num_pages &&
 415             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 416              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 417              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
 418                 fuse_send_readpages(req, data->file, inode);
 419                 data->req = req = fuse_get_req(fc);
 420                 if (IS_ERR(req)) {
 421                         unlock_page(page);
 422                         return PTR_ERR(req);
 423                 }
 424         }
 425         req->pages[req->num_pages] = page;
 426         req->num_pages ++;
 427         return 0;
 428 }
 429
 430 static int fuse_readpages(struct file *file, struct address_space *mapping,
 431                           struct list_head *pages, unsigned nr_pages)
 432 {
 433         struct inode *inode = mapping->host;
 434         struct fuse_conn *fc = get_fuse_conn(inode);
 435         struct fuse_fill_data data;
 436         int err;
 437
 438         err = -EIO;
 439         if (is_bad_inode(inode))
 440                 goto out;
 441
 442         data.file = file;
 443         data.inode = inode;
 444         data.req = fuse_get_req(fc);
 445         err = PTR_ERR(data.req);
 446         if (IS_ERR(data.req))
 447                 goto out;
 448
 449         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
 450         if (!err) {
 451                 if (data.req->num_pages)
 452                         fuse_send_readpages(data.req, file, inode);
 453                 else
 454                         fuse_put_request(fc, data.req);
 455         }
 456 out:
 457         return err;
 458 }
 459
 460 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 461                                   unsigned long nr_segs, loff_t pos)
 462 {
 463         struct inode *inode = iocb->ki_filp->f_mapping->host;
 464
 465         if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
 466                 int err;
 467                 /*
 468                  * If trying to read past EOF, make sure the i_size
 469                  * attribute is up-to-date.
 470                  */
 471                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
 472                 if (err)
 473                         return err;
 474         }
 475
 476         return generic_file_aio_read(iocb, iov, nr_segs, pos);
 477 }
 478
 479 static void fuse_write_fill(struct fuse_req *req, struct file *file,
 480                             struct inode *inode, loff_t pos, size_t count,
 481                             int writepage)
 482 {
 483         struct fuse_conn *fc = get_fuse_conn(inode);
 484         struct fuse_file *ff = file->private_data;
 485         struct fuse_write_in *inarg = &req->misc.write.in;
 486         struct fuse_write_out *outarg = &req->misc.write.out;
 487
 488         memset(inarg, 0, sizeof(struct fuse_write_in));
 489         inarg->fh = ff->fh;
 490         inarg->offset = pos;
 491         inarg->size = count;
 492         inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
 493         inarg->flags = file->f_flags;
 494         req->in.h.opcode = FUSE_WRITE;
 495         req->in.h.nodeid = get_node_id(inode);
 496         req->in.argpages = 1;
 497         req->in.numargs = 2;
 498         if (fc->minor < 9)
 499                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
 500         else
 501                 req->in.args[0].size = sizeof(struct fuse_write_in);
 502         req->in.args[0].value = inarg;
 503         req->in.args[1].size = count;
 504         req->out.numargs = 1;
 505         req->out.args[0].size = sizeof(struct fuse_write_out);
 506         req->out.args[0].value = outarg;
 507 }
 508
 509 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
 510                               struct inode *inode, loff_t pos, size_t count,
 511                               fl_owner_t owner)
 512 {
 513         struct fuse_conn *fc = get_fuse_conn(inode);
 514         fuse_write_fill(req, file, inode, pos, count, 0);
 515         if (owner != NULL) {
 516                 struct fuse_write_in *inarg = &req->misc.write.in;
 517                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
 518                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
 519         }
 520         request_send(fc, req);
 521         return req->misc.write.out.size;
 522 }
 523
 524 static int fuse_write_begin(struct file *file, struct address_space *mapping,
 525                         loff_t pos, unsigned len, unsigned flags,
 526                         struct page **pagep, void **fsdata)
 527 {
 528         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 529
 530         *pagep = __grab_cache_page(mapping, index);
 531         if (!*pagep)
 532                 return -ENOMEM;
 533         return 0;
 534 }
 535
 536 static int fuse_buffered_write(struct file *file, struct inode *inode,
 537                                loff_t pos, unsigned count, struct page *page)
 538 {
 539         int err;
 540         size_t nres;
 541         struct fuse_conn *fc = get_fuse_conn(inode);
 542         struct fuse_inode *fi = get_fuse_inode(inode);
 543         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
 544         struct fuse_req *req;
 545
 546         if (is_bad_inode(inode))
 547                 return -EIO;
 548
 549         req = fuse_get_req(fc);
 550         if (IS_ERR(req))
 551                 return PTR_ERR(req);
 552
 553         req->num_pages = 1;
 554         req->pages[0] = page;
 555         req->page_offset = offset;
 556         nres = fuse_send_write(req, file, inode, pos, count, NULL);
 557         err = req->out.h.error;
 558         fuse_put_request(fc, req);
 559         if (!err && !nres)
 560                 err = -EIO;
 561         if (!err) {
 562                 pos += nres;
 563                 spin_lock(&fc->lock);
 564                 fi->attr_version = ++fc->attr_version;
 565                 if (pos > inode->i_size)
 566                         i_size_write(inode, pos);
 567                 spin_unlock(&fc->lock);
 568
 569                 if (count == PAGE_CACHE_SIZE)
 570                         SetPageUptodate(page);
 571         }
 572         fuse_invalidate_attr(inode);
 573         return err ? err : nres;
 574 }
 575
 576 static int fuse_write_end(struct file *file, struct address_space *mapping,
 577                         loff_t pos, unsigned len, unsigned copied,
 578                         struct page *page, void *fsdata)
 579 {
 580         struct inode *inode = mapping->host;
 581         int res = 0;
 582
 583         if (copied)
 584                 res = fuse_buffered_write(file, inode, pos, copied, page);
 585
 586         unlock_page(page);
 587         page_cache_release(page);
 588         return res;
 589 }
 590
 591 static void fuse_release_user_pages(struct fuse_req *req, int write)
 592 {
 593         unsigned i;
 594
 595         for (i = 0; i < req->num_pages; i++) {
 596                 struct page *page = req->pages[i];
 597                 if (write)
 598                         set_page_dirty_lock(page);
 599                 put_page(page);
 600         }
 601 }
 602
 603 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
 604                                unsigned nbytes, int write)
 605 {
 606         unsigned long user_addr = (unsigned long) buf;
 607         unsigned offset = user_addr & ~PAGE_MASK;
 608         int npages;
 609
 610         /* This doesn't work with nfsd */
 611         if (!current->mm)
 612                 return -EPERM;
 613
 614         nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
 615         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
 616         npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ);
 617         down_read(&current->mm->mmap_sem);
 618         npages = get_user_pages(current, current->mm, user_addr, npages, write,
 619                                 0, req->pages, NULL);
 620         up_read(&current->mm->mmap_sem);
 621         if (npages < 0)
 622                 return npages;
 623
 624         req->num_pages = npages;
 625         req->page_offset = offset;
 626         return 0;
 627 }
 628
 629 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
 630                               size_t count, loff_t *ppos, int write)
 631 {
 632         struct inode *inode = file->f_path.dentry->d_inode;
 633         struct fuse_conn *fc = get_fuse_conn(inode);
 634         size_t nmax = write ? fc->max_write : fc->max_read;
 635         loff_t pos = *ppos;
 636         ssize_t res = 0;
 637         struct fuse_req *req;
 638
 639         if (is_bad_inode(inode))
 640                 return -EIO;
 641
 642         req = fuse_get_req(fc);
 643         if (IS_ERR(req))
 644                 return PTR_ERR(req);
 645
 646         while (count) {
 647                 size_t nres;
 648                 size_t nbytes = min(count, nmax);
 649                 int err = fuse_get_user_pages(req, buf, nbytes, !write);
 650                 if (err) {
 651                         res = err;
 652                         break;
 653                 }
 654                 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
 655                 nbytes = min(count, nbytes);
 656                 if (write)
 657                         nres = fuse_send_write(req, file, inode, pos, nbytes,
 658                                                current->files);
 659                 else
 660                         nres = fuse_send_read(req, file, inode, pos, nbytes,
 661                                               current->files);
 662                 fuse_release_user_pages(req, !write);
 663                 if (req->out.h.error) {
 664                         if (!res)
 665                                 res = req->out.h.error;
 666                         break;
 667                 } else if (nres > nbytes) {
 668                         res = -EIO;
 669                         break;
 670                 }
 671                 count -= nres;
 672                 res += nres;
 673                 pos += nres;
 674                 buf += nres;
 675                 if (nres != nbytes)
 676                         break;
 677                 if (count) {
 678                         fuse_put_request(fc, req);
 679                         req = fuse_get_req(fc);
 680                         if (IS_ERR(req))
 681                                 break;
 682                 }
 683         }
 684         fuse_put_request(fc, req);
 685         if (res > 0) {
 686                 if (write) {
 687                         spin_lock(&fc->lock);
 688                         if (pos > inode->i_size)
 689                                 i_size_write(inode, pos);
 690                         spin_unlock(&fc->lock);
 691                 }
 692                 *ppos = pos;
 693         }
 694         fuse_invalidate_attr(inode);
 695
 696         return res;
 697 }
 698
 699 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
 700                                      size_t count, loff_t *ppos)
 701 {
 702         return fuse_direct_io(file, buf, count, ppos, 0);
 703 }
 704
 705 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
 706                                  size_t count, loff_t *ppos)
 707 {
 708         struct inode *inode = file->f_path.dentry->d_inode;
 709         ssize_t res;
 710         /* Don't allow parallel writes to the same file */
 711         mutex_lock(&inode->i_mutex);
 712         res = generic_write_checks(file, ppos, &count, 0);
 713         if (!res)
 714                 res = fuse_direct_io(file, buf, count, ppos, 1);
 715         mutex_unlock(&inode->i_mutex);
 716         return res;
 717 }
 718
 719 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
 720 {
 721         if ((vma->vm_flags & VM_SHARED)) {
 722                 if ((vma->vm_flags & VM_WRITE))
 723                         return -ENODEV;
 724                 else
 725                         vma->vm_flags &= ~VM_MAYWRITE;
 726         }
 727         return generic_file_mmap(file, vma);
 728 }
 729
 730 static int fuse_set_page_dirty(struct page *page)
 731 {
 732         printk("fuse_set_page_dirty: should not happen\n");
 733         dump_stack();
 734         return 0;
 735 }
 736
 737 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
 738                                   struct file_lock *fl)
 739 {
 740         switch (ffl->type) {
 741         case F_UNLCK:
 742                 break;
 743
 744         case F_RDLCK:
 745         case F_WRLCK:
 746                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
 747                     ffl->end < ffl->start)
 748                         return -EIO;
 749
 750                 fl->fl_start = ffl->start;
 751                 fl->fl_end = ffl->end;
 752                 fl->fl_pid = ffl->pid;
 753                 break;
 754
 755         default:
 756                 return -EIO;
 757         }
 758         fl->fl_type = ffl->type;
 759         return 0;
 760 }
 761
 762 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
 763                          const struct file_lock *fl, int opcode, pid_t pid,
 764                          int flock)
 765 {
 766         struct inode *inode = file->f_path.dentry->d_inode;
 767         struct fuse_conn *fc = get_fuse_conn(inode);
 768         struct fuse_file *ff = file->private_data;
 769         struct fuse_lk_in *arg = &req->misc.lk_in;
 770
 771         arg->fh = ff->fh;
 772         arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
 773         arg->lk.start = fl->fl_start;
 774         arg->lk.end = fl->fl_end;
 775         arg->lk.type = fl->fl_type;
 776         arg->lk.pid = pid;
 777         if (flock)
 778                 arg->lk_flags |= FUSE_LK_FLOCK;
 779         req->in.h.opcode = opcode;
 780         req->in.h.nodeid = get_node_id(inode);
 781         req->in.numargs = 1;
 782         req->in.args[0].size = sizeof(*arg);
 783         req->in.args[0].value = arg;
 784 }
 785
 786 static int fuse_getlk(struct file *file, struct file_lock *fl)
 787 {
 788         struct inode *inode = file->f_path.dentry->d_inode;
 789         struct fuse_conn *fc = get_fuse_conn(inode);
 790         struct fuse_req *req;
 791         struct fuse_lk_out outarg;
 792         int err;
 793
 794         req = fuse_get_req(fc);
 795         if (IS_ERR(req))
 796                 return PTR_ERR(req);
 797
 798         fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
 799         req->out.numargs = 1;
 800         req->out.args[0].size = sizeof(outarg);
 801         req->out.args[0].value = &outarg;
 802         request_send(fc, req);
 803         err = req->out.h.error;
 804         fuse_put_request(fc, req);
 805         if (!err)
 806                 err = convert_fuse_file_lock(&outarg.lk, fl);
 807
 808         return err;
 809 }
 810
 811 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
 812 {
 813         struct inode *inode = file->f_path.dentry->d_inode;
 814         struct fuse_conn *fc = get_fuse_conn(inode);
 815         struct fuse_req *req;
 816         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
 817         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
 818         int err;
 819
 820         /* Unlock on close is handled by the flush method */
 821         if (fl->fl_flags & FL_CLOSE)
 822                 return 0;
 823
 824         req = fuse_get_req(fc);
 825         if (IS_ERR(req))
 826                 return PTR_ERR(req);
 827
 828         fuse_lk_fill(req, file, fl, opcode, pid, flock);
 829         request_send(fc, req);
 830         err = req->out.h.error;
 831         /* locking is restartable */
 832         if (err == -EINTR)
 833                 err = -ERESTARTSYS;
 834         fuse_put_request(fc, req);
 835         return err;
 836 }
 837
 838 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
 839 {
 840         struct inode *inode = file->f_path.dentry->d_inode;
 841         struct fuse_conn *fc = get_fuse_conn(inode);
 842         int err;
 843
 844         if (cmd == F_GETLK) {
 845                 if (fc->no_lock) {
 846                         posix_test_lock(file, fl);
 847                         err = 0;
 848                 } else
 849                         err = fuse_getlk(file, fl);
 850         } else {
 851                 if (fc->no_lock)
 852                         err = posix_lock_file_wait(file, fl);
 853                 else
 854                         err = fuse_setlk(file, fl, 0);
 855         }
 856         return err;
 857 }
 858
 859 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
 860 {
 861         struct inode *inode = file->f_path.dentry->d_inode;
 862         struct fuse_conn *fc = get_fuse_conn(inode);
 863         int err;
 864
 865         if (fc->no_lock) {
 866                 err = flock_lock_file_wait(file, fl);
 867         } else {
 868                 /* emulate flock with POSIX locks */
 869                 fl->fl_owner = (fl_owner_t) file;
 870                 err = fuse_setlk(file, fl, 1);
 871         }
 872
 873         return err;
 874 }
 875
 876 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
 877 {
 878         struct inode *inode = mapping->host;
 879         struct fuse_conn *fc = get_fuse_conn(inode);
 880         struct fuse_req *req;
 881         struct fuse_bmap_in inarg;
 882         struct fuse_bmap_out outarg;
 883         int err;
 884
 885         if (!inode->i_sb->s_bdev || fc->no_bmap)
 886                 return 0;
 887
 888         req = fuse_get_req(fc);
 889         if (IS_ERR(req))
 890                 return 0;
 891
 892         memset(&inarg, 0, sizeof(inarg));
 893         inarg.block = block;
 894         inarg.blocksize = inode->i_sb->s_blocksize;
 895         req->in.h.opcode = FUSE_BMAP;
 896         req->in.h.nodeid = get_node_id(inode);
 897         req->in.numargs = 1;
 898         req->in.args[0].size = sizeof(inarg);
 899         req->in.args[0].value = &inarg;
 900         req->out.numargs = 1;
 901         req->out.args[0].size = sizeof(outarg);
 902         req->out.args[0].value = &outarg;
 903         request_send(fc, req);
 904         err = req->out.h.error;
 905         fuse_put_request(fc, req);
 906         if (err == -ENOSYS)
 907                 fc->no_bmap = 1;
 908
 909         return err ? 0 : outarg.block;
 910 }
 911
 912 static const struct file_operations fuse_file_operations = {
 913         .llseek         = generic_file_llseek,
 914         .read           = do_sync_read,
 915         .aio_read       = fuse_file_aio_read,
 916         .write          = do_sync_write,
 917         .aio_write      = generic_file_aio_write,
 918         .mmap           = fuse_file_mmap,
 919         .open           = fuse_open,
 920         .flush          = fuse_flush,
 921         .release        = fuse_release,
 922         .fsync          = fuse_fsync,
 923         .lock           = fuse_file_lock,
 924         .flock          = fuse_file_flock,
 925         .splice_read    = generic_file_splice_read,
 926 };
 927
 928 static const struct file_operations fuse_direct_io_file_operations = {
 929         .llseek         = generic_file_llseek,
 930         .read           = fuse_direct_read,
 931         .write          = fuse_direct_write,
 932         .open           = fuse_open,
 933         .flush          = fuse_flush,
 934         .release        = fuse_release,
 935         .fsync          = fuse_fsync,
 936         .lock           = fuse_file_lock,
 937         .flock          = fuse_file_flock,
 938         /* no mmap and splice_read */
 939 };
 940
 941 static const struct address_space_operations fuse_file_aops  = {
 942         .readpage       = fuse_readpage,
 943         .write_begin    = fuse_write_begin,
 944         .write_end      = fuse_write_end,
 945         .readpages      = fuse_readpages,
 946         .set_page_dirty = fuse_set_page_dirty,
 947         .bmap           = fuse_bmap,
 948 };
 949
 950 void fuse_init_file_inode(struct inode *inode)
 951 {
 952         inode->i_fop = &fuse_file_operations;
 953         inode->i_data.a_ops = &fuse_file_aops;
 954 }