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