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