source3/smbd/fileio.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    read/write to a files_struct
   5    Copyright (C) Andrew Tridgell 1992-1998
   6    Copyright (C) Jeremy Allison 2000-2002. - write cache.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 static BOOL setup_write_cache(files_struct *, SMB_OFF_T);
  26
  27 /****************************************************************************
  28  Read from write cache if we can.
  29 ****************************************************************************/
  30
  31 static BOOL read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  32 {
  33         write_cache *wcp = fsp->wcp;
  34
  35         if(!wcp) {
  36                 return False;
  37         }
  38
  39         if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) {
  40                 return False;
  41         }
  42
  43         memcpy(data, wcp->data + (pos - wcp->offset), n);
  44
  45         DO_PROFILE_INC(writecache_read_hits);
  46
  47         return True;
  48 }
  49
  50 /****************************************************************************
  51  Read from a file.
  52 ****************************************************************************/
  53
  54 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  55 {
  56         ssize_t ret=0,readret;
  57
  58         /* you can't read from print files */
  59         if (fsp->print_file) {
  60                 return -1;
  61         }
  62
  63         /*
  64          * Serve from write cache if we can.
  65          */
  66
  67         if(read_from_write_cache(fsp, data, pos, n)) {
  68                 fsp->fh->pos = pos + n;
  69                 fsp->fh->position_information = fsp->fh->pos;
  70                 return n;
  71         }
  72
  73         flush_write_cache(fsp, READ_FLUSH);
  74
  75         fsp->fh->pos = pos;
  76
  77         if (n > 0) {
  78 #ifdef DMF_FIX
  79                 int numretries = 3;
  80 tryagain:
  81                 readret = SMB_VFS_PREAD(fsp,fsp->fh->fd,data,n,pos);
  82
  83                 if (readret == -1) {
  84                         if ((errno == EAGAIN) && numretries) {
  85                                 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
  86                                 (void)sleep(10);
  87                                 --numretries;
  88                                 goto tryagain;
  89                         }
  90                         return -1;
  91                 }
  92 #else /* NO DMF fix. */
  93                 readret = SMB_VFS_PREAD(fsp,fsp->fh->fd,data,n,pos);
  94
  95                 if (readret == -1) {
  96                         return -1;
  97                 }
  98 #endif
  99                 if (readret > 0) {
 100                         ret += readret;
 101                 }
 102         }
 103
 104         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
 105                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 106
 107         fsp->fh->pos += ret;
 108         fsp->fh->position_information = fsp->fh->pos;
 109
 110         return(ret);
 111 }
 112
 113 /* how many write cache buffers have been allocated */
 114 static unsigned int allocated_write_caches;
 115
 116 /****************************************************************************
 117  *Really* write to a file.
 118 ****************************************************************************/
 119
 120 static ssize_t real_write_file(files_struct *fsp,const char *data, SMB_OFF_T pos, size_t n)
 121 {
 122         ssize_t ret;
 123
 124         if (pos == -1) {
 125                 ret = vfs_write_data(fsp, data, n);
 126         } else {
 127                 fsp->fh->pos = pos;
 128                 if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
 129                         if (vfs_fill_sparse(fsp, pos) == -1) {
 130                                 return -1;
 131                         }
 132                 }
 133                 ret = vfs_pwrite_data(fsp, data, n, pos);
 134         }
 135
 136         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 137                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 138
 139         if (ret != -1) {
 140                 fsp->fh->pos += ret;
 141
 142                 /*
 143                  * It turns out that setting the last write time from a Windows
 144                  * client stops any subsequent writes from updating the write time.
 145                  * Doing this after the write gives a race condition here where
 146                  * a stat may see the changed write time before we reset it here,
 147                  * but it's cheaper than having to store the write time in shared
 148                  * memory and look it up using dev/inode across all running smbd's.
 149                  * The 99% solution will hopefully be good enough in this case. JRA.
 150                  */
 151
 152                 if (!null_timespec(fsp->pending_modtime)) {
 153                         set_filetime(fsp->conn, fsp->fsp_name, fsp->pending_modtime);
 154
 155                         /* If we didn't get the "set modtime" call ourselves, we must
 156                            store the last write time to restore on close. JRA. */
 157                         if (!fsp->pending_modtime_owner) {
 158                                 fsp->last_write_time = timespec_current();
 159                         }
 160                 }
 161
 162 /* Yes - this is correct - writes don't update this. JRA. */
 163 /* Found by Samba4 tests. */
 164 #if 0
 165                 fsp->position_information = fsp->pos;
 166 #endif
 167         }
 168
 169         return ret;
 170 }
 171
 172 /****************************************************************************
 173  File size cache change.
 174  Updates size on disk but doesn't flush the cache.
 175 ****************************************************************************/
 176
 177 static int wcp_file_size_change(files_struct *fsp)
 178 {
 179         int ret;
 180         write_cache *wcp = fsp->wcp;
 181
 182         wcp->file_size = wcp->offset + wcp->data_size;
 183         ret = SMB_VFS_FTRUNCATE(fsp, fsp->fh->fd, wcp->file_size);
 184         if (ret == -1) {
 185                 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f error %s\n",
 186                         fsp->fsp_name, (double)wcp->file_size, strerror(errno) ));
 187         }
 188         return ret;
 189 }
 190
 191 /****************************************************************************
 192  Write to a file.
 193 ****************************************************************************/
 194
 195 ssize_t write_file(files_struct *fsp, const char *data, SMB_OFF_T pos, size_t n)
 196 {
 197         write_cache *wcp = fsp->wcp;
 198         ssize_t total_written = 0;
 199         int write_path = -1;
 200
 201         if (fsp->print_file) {
 202                 fstring sharename;
 203                 uint32 jobid;
 204
 205                 if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
 206                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
 207                                                 (unsigned int)fsp->rap_print_jobid ));
 208                         errno = EBADF;
 209                         return -1;
 210                 }
 211
 212                 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
 213         }
 214
 215         if (!fsp->can_write) {
 216                 errno = EPERM;
 217                 return -1;
 218         }
 219
 220         if (!fsp->modified) {
 221                 SMB_STRUCT_STAT st;
 222                 fsp->modified = True;
 223
 224                 if (SMB_VFS_FSTAT(fsp,fsp->fh->fd,&st) == 0) {
 225                         int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
 226                         if ((lp_store_dos_attributes(SNUM(fsp->conn)) || MAP_ARCHIVE(fsp->conn)) && !IS_DOS_ARCHIVE(dosmode)) {
 227                                 file_set_dosmode(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st, False);
 228                         }
 229
 230                         /*
 231                          * If this is the first write and we have an exclusive oplock then setup
 232                          * the write cache.
 233                          */
 234
 235                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
 236                                 setup_write_cache(fsp, st.st_size);
 237                                 wcp = fsp->wcp;
 238                         }
 239                 }
 240         }
 241
 242 #ifdef WITH_PROFILE
 243         DO_PROFILE_INC(writecache_total_writes);
 244         if (!fsp->oplock_type) {
 245                 DO_PROFILE_INC(writecache_non_oplock_writes);
 246         }
 247 #endif
 248
 249         /*
 250          * If this file is level II oplocked then we need
 251          * to grab the shared memory lock and inform all
 252          * other files with a level II lock that they need
 253          * to flush their read caches. We keep the lock over
 254          * the shared memory area whilst doing this.
 255          */
 256
 257         release_level_2_oplocks_on_change(fsp);
 258
 259 #ifdef WITH_PROFILE
 260         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
 261                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
 262 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
 263                         profile_p->writecache_init_writes,
 264                         profile_p->writecache_abutted_writes,
 265                         profile_p->writecache_total_writes,
 266                         profile_p->writecache_non_oplock_writes,
 267                         profile_p->writecache_allocated_write_caches,
 268                         profile_p->writecache_num_write_caches,
 269                         profile_p->writecache_direct_writes,
 270                         profile_p->writecache_num_perfect_writes,
 271                         profile_p->writecache_read_hits ));
 272
 273                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
 274                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
 275                         profile_p->writecache_flushed_writes[READ_FLUSH],
 276                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
 277                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
 278                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
 279                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
 280                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
 281         }
 282 #endif
 283
 284         if(!wcp) {
 285                 DO_PROFILE_INC(writecache_direct_writes);
 286                 total_written = real_write_file(fsp, data, pos, n);
 287                 return total_written;
 288         }
 289
 290         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
 291                 fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
 292
 293         fsp->fh->pos = pos + n;
 294
 295         /*
 296          * If we have active cache and it isn't contiguous then we flush.
 297          * NOTE: There is a small problem with running out of disk ....
 298          */
 299
 300         if (wcp->data_size) {
 301                 BOOL cache_flush_needed = False;
 302
 303                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 304
 305                         /* ASCII art.... JRA.
 306
 307       +--------------+-----
 308       | Cached data  | Rest of allocated cache buffer....
 309       +--------------+-----
 310
 311             +-------------------+
 312             | Data to write     |
 313             +-------------------+
 314
 315                         */
 316
 317                         /*
 318                          * Start of write overlaps or abutts the existing data.
 319                          */
 320
 321                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 322
 323                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 324
 325                         /*
 326                          * Update the current buffer size with the new data.
 327                          */
 328
 329                         if(pos + data_used > wcp->offset + wcp->data_size) {
 330                                 wcp->data_size = pos + data_used - wcp->offset;
 331                         }
 332
 333                         /*
 334                          * Update the file size if changed.
 335                          */
 336
 337                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 338                                 if (wcp_file_size_change(fsp) == -1) {
 339                                         return -1;
 340                                 }
 341                         }
 342
 343                         /*
 344                          * If we used all the data then
 345                          * return here.
 346                          */
 347
 348                         if(n == data_used) {
 349                                 return n;
 350                         } else {
 351                                 cache_flush_needed = True;
 352                         }
 353                         /*
 354                          * Move the start of data forward by the amount used,
 355                          * cut down the amount left by the same amount.
 356                          */
 357
 358                         data += data_used;
 359                         pos += data_used;
 360                         n -= data_used;
 361
 362                         DO_PROFILE_INC(writecache_abutted_writes);
 363                         total_written = data_used;
 364
 365                         write_path = 1;
 366
 367                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 368                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 369
 370                         /* ASCII art.... JRA.
 371
 372                         +---------------+
 373                         | Cache buffer  |
 374                         +---------------+
 375
 376             +-------------------+
 377             | Data to write     |
 378             +-------------------+
 379
 380                         */
 381
 382                         /*
 383                          * End of write overlaps the existing data.
 384                          */
 385
 386                         size_t data_used = pos + n - wcp->offset;
 387
 388                         memcpy(wcp->data, data + n - data_used, data_used);
 389
 390                         /*
 391                          * Update the current buffer size with the new data.
 392                          */
 393
 394                         if(pos + n > wcp->offset + wcp->data_size) {
 395                                 wcp->data_size = pos + n - wcp->offset;
 396                         }
 397
 398                         /*
 399                          * Update the file size if changed.
 400                          */
 401
 402                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 403                                 if (wcp_file_size_change(fsp) == -1) {
 404                                         return -1;
 405                                 }
 406                         }
 407
 408                         /*
 409                          * We don't need to move the start of data, but we
 410                          * cut down the amount left by the amount used.
 411                          */
 412
 413                         n -= data_used;
 414
 415                         /*
 416                          * We cannot have used all the data here.
 417                          */
 418
 419                         cache_flush_needed = True;
 420
 421                         DO_PROFILE_INC(writecache_abutted_writes);
 422                         total_written = data_used;
 423
 424                         write_path = 2;
 425
 426                 } else if ( (pos >= wcp->file_size) &&
 427                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 428                                         (pos > wcp->offset + wcp->data_size) &&
 429                                         (pos < wcp->offset + wcp->alloc_size) ) {
 430
 431                         /* ASCII art.... JRA.
 432
 433                        End of file ---->|
 434
 435                         +---------------+---------------+
 436                         | Cached data   | Cache buffer  |
 437                         +---------------+---------------+
 438
 439                                               +-------------------+
 440                                               | Data to write     |
 441                                               +-------------------+
 442
 443                         */
 444
 445                         /*
 446                          * Non-contiguous write part of which fits within
 447                          * the cache buffer and is extending the file
 448                          * and the cache contents reflect the current
 449                          * data up to the current end of the file.
 450                          */
 451
 452                         size_t data_used;
 453
 454                         if(pos + n <= wcp->offset + wcp->alloc_size) {
 455                                 data_used = n;
 456                         } else {
 457                                 data_used = wcp->offset + wcp->alloc_size - pos;
 458                         }
 459
 460                         /*
 461                          * Fill in the non-continuous area with zeros.
 462                          */
 463
 464                         memset(wcp->data + wcp->data_size, '\0',
 465                                 pos - (wcp->offset + wcp->data_size) );
 466
 467                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 468
 469                         /*
 470                          * Update the current buffer size with the new data.
 471                          */
 472
 473                         if(pos + data_used > wcp->offset + wcp->data_size) {
 474                                 wcp->data_size = pos + data_used - wcp->offset;
 475                         }
 476
 477                         /*
 478                          * Update the file size if changed.
 479                          */
 480
 481                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 482                                 if (wcp_file_size_change(fsp) == -1) {
 483                                         return -1;
 484                                 }
 485                         }
 486
 487                         /*
 488                          * If we used all the data then
 489                          * return here.
 490                          */
 491
 492                         if(n == data_used) {
 493                                 return n;
 494                         } else {
 495                                 cache_flush_needed = True;
 496                         }
 497
 498                         /*
 499                          * Move the start of data forward by the amount used,
 500                          * cut down the amount left by the same amount.
 501                          */
 502
 503                         data += data_used;
 504                         pos += data_used;
 505                         n -= data_used;
 506
 507                         DO_PROFILE_INC(writecache_abutted_writes);
 508                         total_written = data_used;
 509
 510                         write_path = 3;
 511
 512                 } else if ( (pos >= wcp->file_size) &&
 513                             (n == 1) &&
 514                             (pos < wcp->offset + 2*wcp->alloc_size) &&
 515                             (wcp->file_size == wcp->offset + wcp->data_size)) {
 516
 517                         /*
 518                         +---------------+
 519                         | Cached data   |
 520                         +---------------+
 521
 522                                                          +--------+
 523                                                          | 1 Byte |
 524                                                          +--------+
 525
 526                         MS-Office seems to do this a lot to determine if there's enough
 527                         space on the filesystem to write a new file.
 528                         */
 529
 530                         SMB_BIG_UINT new_start = wcp->offset + wcp->data_size;
 531
 532                         flush_write_cache(fsp, WRITE_FLUSH);
 533                         wcp->offset = new_start;
 534                         wcp->data_size = pos - new_start + 1;
 535                         memset(wcp->data, '\0', wcp->data_size);
 536                         memcpy(wcp->data + wcp->data_size-1, data, 1);
 537
 538                         /*
 539                          * Update the file size if changed.
 540                          */
 541
 542                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 543                                 if (wcp_file_size_change(fsp) == -1) {
 544                                         return -1;
 545                                 }
 546                         }
 547
 548                         return n;
 549
 550                 } else {
 551
 552                         /* ASCII art..... JRA.
 553
 554    Case 1).
 555
 556                         +---------------+---------------+
 557                         | Cached data   | Cache buffer  |
 558                         +---------------+---------------+
 559
 560                                                               +-------------------+
 561                                                               | Data to write     |
 562                                                               +-------------------+
 563
 564    Case 2).
 565
 566                            +---------------+---------------+
 567                            | Cached data   | Cache buffer  |
 568                            +---------------+---------------+
 569
 570    +-------------------+
 571    | Data to write     |
 572    +-------------------+
 573
 574     Case 3).
 575
 576                            +---------------+---------------+
 577                            | Cached data   | Cache buffer  |
 578                            +---------------+---------------+
 579
 580                   +-----------------------------------------------------+
 581                   | Data to write                                       |
 582                   +-----------------------------------------------------+
 583
 584                   */
 585
 586                         /*
 587                          * Write is bigger than buffer, or there is no overlap on the
 588                          * low or high ends.
 589                          */
 590
 591                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 592 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 593
 594                         /*
 595                          * If write would fit in the cache, and is larger than
 596                          * the data already in the cache, flush the cache and
 597                          * preferentially copy the data new data into it. Otherwise
 598                          * just write the data directly.
 599                          */
 600
 601                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 602                                 cache_flush_needed = True;
 603                         } else {
 604                                 ssize_t ret = real_write_file(fsp, data, pos, n);
 605
 606                                 /*
 607                                  * If the write overlaps the entire cache, then
 608                                  * discard the current contents of the cache.
 609                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 610                                  */
 611
 612                                 if ((pos <= wcp->offset) &&
 613                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 614                                         DEBUG(9,("write_file: discarding overwritten write \
 615 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 616                                         wcp->data_size = 0;
 617                                 }
 618
 619                                 DO_PROFILE_INC(writecache_direct_writes);
 620                                 if (ret == -1) {
 621                                         return ret;
 622                                 }
 623
 624                                 if (pos + ret > wcp->file_size) {
 625                                         wcp->file_size = pos + ret;
 626                                 }
 627
 628                                 return ret;
 629                         }
 630
 631                         write_path = 4;
 632
 633                 }
 634
 635                 if (cache_flush_needed) {
 636                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 637 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 638                                 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 639                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 640
 641                         flush_write_cache(fsp, WRITE_FLUSH);
 642                 }
 643         }
 644
 645         /*
 646          * If the write request is bigger than the cache
 647          * size, write it all out.
 648          */
 649
 650         if (n > wcp->alloc_size ) {
 651                 ssize_t ret = real_write_file(fsp, data, pos, n);
 652                 if (ret == -1) {
 653                         return -1;
 654                 }
 655
 656                 if (pos + ret > wcp->file_size) {
 657                         wcp->file_size = pos + n;
 658                 }
 659
 660                 DO_PROFILE_INC(writecache_direct_writes);
 661                 return total_written + n;
 662         }
 663
 664         /*
 665          * If there's any data left, cache it.
 666          */
 667
 668         if (n) {
 669 #ifdef WITH_PROFILE
 670                 if (wcp->data_size) {
 671                         DO_PROFILE_INC(writecache_abutted_writes);
 672                 } else {
 673                         DO_PROFILE_INC(writecache_init_writes);
 674                 }
 675 #endif
 676                 memcpy(wcp->data+wcp->data_size, data, n);
 677                 if (wcp->data_size == 0) {
 678                         wcp->offset = pos;
 679                         DO_PROFILE_INC(writecache_num_write_caches);
 680                 }
 681                 wcp->data_size += n;
 682
 683                 /*
 684                  * Update the file size if changed.
 685                  */
 686
 687                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 688                         if (wcp_file_size_change(fsp) == -1) {
 689                                 return -1;
 690                         }
 691                 }
 692                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 693                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 694
 695                 total_written += n;
 696                 return total_written; /* .... that's a write :) */
 697         }
 698
 699         return total_written;
 700 }
 701
 702 /****************************************************************************
 703  Delete the write cache structure.
 704 ****************************************************************************/
 705
 706 void delete_write_cache(files_struct *fsp)
 707 {
 708         write_cache *wcp;
 709
 710         if(!fsp) {
 711                 return;
 712         }
 713
 714         if(!(wcp = fsp->wcp)) {
 715                 return;
 716         }
 717
 718         DO_PROFILE_DEC(writecache_allocated_write_caches);
 719         allocated_write_caches--;
 720
 721         SMB_ASSERT(wcp->data_size == 0);
 722
 723         SAFE_FREE(wcp->data);
 724         SAFE_FREE(fsp->wcp);
 725
 726         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
 727 }
 728
 729 /****************************************************************************
 730  Setup the write cache structure.
 731 ****************************************************************************/
 732
 733 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 734 {
 735         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 736         write_cache *wcp;
 737
 738         if (allocated_write_caches >= MAX_WRITE_CACHES) {
 739                 return False;
 740         }
 741
 742         if(alloc_size == 0 || fsp->wcp) {
 743                 return False;
 744         }
 745
 746         if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
 747                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 748                 return False;
 749         }
 750
 751         wcp->file_size = file_size;
 752         wcp->offset = 0;
 753         wcp->alloc_size = alloc_size;
 754         wcp->data_size = 0;
 755         if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
 756                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 757                         (unsigned int)wcp->alloc_size ));
 758                 SAFE_FREE(wcp);
 759                 return False;
 760         }
 761
 762         memset(wcp->data, '\0', wcp->alloc_size );
 763
 764         fsp->wcp = wcp;
 765         DO_PROFILE_INC(writecache_allocated_write_caches);
 766         allocated_write_caches++;
 767
 768         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 769                 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
 770
 771         return True;
 772 }
 773
 774 /****************************************************************************
 775  Cope with a size change.
 776 ****************************************************************************/
 777
 778 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 779 {
 780         if(fsp->wcp) {
 781                 /* The cache *must* have been flushed before we do this. */
 782                 if (fsp->wcp->data_size != 0) {
 783                         char *msg;
 784                         asprintf(&msg, "set_filelen_write_cache: size change "
 785                                  "on file %s with write cache size = %lu\n",
 786                                  fsp->fsp_name,
 787                                  (unsigned long)fsp->wcp->data_size);
 788                         smb_panic(msg);
 789                 }
 790                 fsp->wcp->file_size = file_size;
 791         }
 792 }
 793
 794 /*******************************************************************
 795  Flush a write cache struct to disk.
 796 ********************************************************************/
 797
 798 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 799 {
 800         write_cache *wcp = fsp->wcp;
 801         size_t data_size;
 802         ssize_t ret;
 803
 804         if(!wcp || !wcp->data_size) {
 805                 return 0;
 806         }
 807
 808         data_size = wcp->data_size;
 809         wcp->data_size = 0;
 810
 811         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 812
 813         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 814                 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
 815
 816 #ifdef WITH_PROFILE
 817         if(data_size == wcp->alloc_size) {
 818                 DO_PROFILE_INC(writecache_num_perfect_writes);
 819         }
 820 #endif
 821
 822         ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
 823
 824         /*
 825          * Ensure file size if kept up to date if write extends file.
 826          */
 827
 828         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
 829                 wcp->file_size = wcp->offset + ret;
 830         }
 831
 832         return ret;
 833 }
 834
 835 /*******************************************************************
 836 sync a file
 837 ********************************************************************/
 838
 839 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, BOOL write_through)
 840 {
 841         if (fsp->fh->fd == -1)
 842                 return NT_STATUS_INVALID_HANDLE;
 843
 844         if (lp_strict_sync(SNUM(conn)) &&
 845             (lp_syncalways(SNUM(conn)) || write_through)) {
 846                 int ret = flush_write_cache(fsp, SYNC_FLUSH);
 847                 if (ret == -1) {
 848                         return map_nt_error_from_unix(errno);
 849                 }
 850                 ret = SMB_VFS_FSYNC(fsp,fsp->fh->fd);
 851                 if (ret == -1) {
 852                         return map_nt_error_from_unix(errno);
 853                 }
 854         }
 855         return NT_STATUS_OK;
 856 }
 857
 858 /************************************************************
 859  Perform a stat whether a valid fd or not.
 860 ************************************************************/
 861
 862 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
 863 {
 864         if (fsp->fh->fd == -1) {
 865                 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
 866         } else {
 867                 return SMB_VFS_FSTAT(fsp,fsp->fh->fd, pst);
 868         }
 869 }