source/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->pos = pos + n;
  69                 fsp->position_information = fsp->pos;
  70                 return n;
  71         }
  72
  73         flush_write_cache(fsp, READ_FLUSH);
  74
  75         fsp->pos = pos;
  76
  77         if (n > 0) {
  78 #ifdef DMF_FIX
  79                 int numretries = 3;
  80 tryagain:
  81                 readret = SMB_VFS_PREAD(fsp,fsp->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->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->pos += ret;
 108         fsp->position_information = fsp->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->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->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 (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 = time(NULL);
 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->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(0);
 218         }
 219
 220         if (!fsp->modified) {
 221                 SMB_STRUCT_STAT st;
 222                 fsp->modified = True;
 223
 224                 if (SMB_VFS_FSTAT(fsp,fsp->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->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
 292
 293         fsp->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 {
 513
 514                         /* ASCII art..... JRA.
 515
 516    Case 1).
 517
 518                         +---------------+---------------+
 519                         | Cached data   | Cache buffer  |
 520                         +---------------+---------------+
 521
 522                                                               +-------------------+
 523                                                               | Data to write     |
 524                                                               +-------------------+
 525
 526    Case 2).
 527
 528                            +---------------+---------------+
 529                            | Cached data   | Cache buffer  |
 530                            +---------------+---------------+
 531
 532    +-------------------+
 533    | Data to write     |
 534    +-------------------+
 535
 536     Case 3).
 537
 538                            +---------------+---------------+
 539                            | Cached data   | Cache buffer  |
 540                            +---------------+---------------+
 541
 542                   +-----------------------------------------------------+
 543                   | Data to write                                       |
 544                   +-----------------------------------------------------+
 545
 546                   */
 547
 548                         /*
 549                          * Write is bigger than buffer, or there is no overlap on the
 550                          * low or high ends.
 551                          */
 552
 553                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 554 len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 555
 556                         /*
 557                          * If write would fit in the cache, and is larger than
 558                          * the data already in the cache, flush the cache and
 559                          * preferentially copy the data new data into it. Otherwise
 560                          * just write the data directly.
 561                          */
 562
 563                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 564                                 cache_flush_needed = True;
 565                         } else {
 566                                 ssize_t ret = real_write_file(fsp, data, pos, n);
 567
 568                                 /*
 569                                  * If the write overlaps the entire cache, then
 570                                  * discard the current contents of the cache.
 571                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 572                                  */
 573
 574                                 if ((pos <= wcp->offset) &&
 575                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 576                                         DEBUG(9,("write_file: discarding overwritten write \
 577 cache: fd = %d, off=%.0f, size=%u\n", fsp->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 578                                         wcp->data_size = 0;
 579                                 }
 580
 581                                 DO_PROFILE_INC(writecache_direct_writes);
 582                                 if (ret == -1) {
 583                                         return ret;
 584                                 }
 585
 586                                 if (pos + ret > wcp->file_size) {
 587                                         wcp->file_size = pos + ret;
 588                                 }
 589
 590                                 return ret;
 591                         }
 592
 593                         write_path = 4;
 594
 595                 }
 596
 597                 if (cache_flush_needed) {
 598                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 599 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 600                                 write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 601                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 602
 603                         flush_write_cache(fsp, WRITE_FLUSH);
 604                 }
 605         }
 606
 607         /*
 608          * If the write request is bigger than the cache
 609          * size, write it all out.
 610          */
 611
 612         if (n > wcp->alloc_size ) {
 613                 ssize_t ret = real_write_file(fsp, data, pos, n);
 614                 if (ret == -1) {
 615                         return -1;
 616                 }
 617
 618                 if (pos + ret > wcp->file_size) {
 619                         wcp->file_size = pos + n;
 620                 }
 621
 622                 DO_PROFILE_INC(writecache_direct_writes);
 623                 return total_written + n;
 624         }
 625
 626         /*
 627          * If there's any data left, cache it.
 628          */
 629
 630         if (n) {
 631 #ifdef WITH_PROFILE
 632                 if (wcp->data_size) {
 633                         DO_PROFILE_INC(writecache_abutted_writes);
 634                 } else {
 635                         DO_PROFILE_INC(writecache_init_writes);
 636                 }
 637 #endif
 638                 memcpy(wcp->data+wcp->data_size, data, n);
 639                 if (wcp->data_size == 0) {
 640                         wcp->offset = pos;
 641                         DO_PROFILE_INC(writecache_num_write_caches);
 642                 }
 643                 wcp->data_size += n;
 644
 645                 /*
 646                  * Update the file size if changed.
 647                  */
 648
 649                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 650                         if (wcp_file_size_change(fsp) == -1) {
 651                                 return -1;
 652                         }
 653                 }
 654                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 655                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 656
 657                 total_written += n;
 658                 return total_written; /* .... that's a write :) */
 659         }
 660
 661         return total_written;
 662 }
 663
 664 /****************************************************************************
 665  Delete the write cache structure.
 666 ****************************************************************************/
 667
 668 void delete_write_cache(files_struct *fsp)
 669 {
 670         write_cache *wcp;
 671
 672         if(!fsp) {
 673                 return;
 674         }
 675
 676         if(!(wcp = fsp->wcp)) {
 677                 return;
 678         }
 679
 680         DO_PROFILE_DEC(writecache_allocated_write_caches);
 681         allocated_write_caches--;
 682
 683         SMB_ASSERT(wcp->data_size == 0);
 684
 685         SAFE_FREE(wcp->data);
 686         SAFE_FREE(fsp->wcp);
 687
 688         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
 689 }
 690
 691 /****************************************************************************
 692  Setup the write cache structure.
 693 ****************************************************************************/
 694
 695 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 696 {
 697         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 698         write_cache *wcp;
 699
 700         if (allocated_write_caches >= MAX_WRITE_CACHES) {
 701                 return False;
 702         }
 703
 704         if(alloc_size == 0 || fsp->wcp) {
 705                 return False;
 706         }
 707
 708         if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
 709                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 710                 return False;
 711         }
 712
 713         wcp->file_size = file_size;
 714         wcp->offset = 0;
 715         wcp->alloc_size = alloc_size;
 716         wcp->data_size = 0;
 717         if((wcp->data = SMB_MALLOC(wcp->alloc_size)) == NULL) {
 718                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 719                         (unsigned int)wcp->alloc_size ));
 720                 SAFE_FREE(wcp);
 721                 return False;
 722         }
 723
 724         memset(wcp->data, '\0', wcp->alloc_size );
 725
 726         fsp->wcp = wcp;
 727         DO_PROFILE_INC(writecache_allocated_write_caches);
 728         allocated_write_caches++;
 729
 730         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 731                 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
 732
 733         return True;
 734 }
 735
 736 /****************************************************************************
 737  Cope with a size change.
 738 ****************************************************************************/
 739
 740 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 741 {
 742         if(fsp->wcp) {
 743                 /* The cache *must* have been flushed before we do this. */
 744                 if (fsp->wcp->data_size != 0) {
 745                         pstring msg;
 746                         slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
 747 on file %s with write cache size = %lu\n", fsp->fsp_name, (unsigned long)fsp->wcp->data_size );
 748                         smb_panic(msg);
 749                 }
 750                 fsp->wcp->file_size = file_size;
 751         }
 752 }
 753
 754 /*******************************************************************
 755  Flush a write cache struct to disk.
 756 ********************************************************************/
 757
 758 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 759 {
 760         write_cache *wcp = fsp->wcp;
 761         size_t data_size;
 762         ssize_t ret;
 763
 764         if(!wcp || !wcp->data_size) {
 765                 return 0;
 766         }
 767
 768         data_size = wcp->data_size;
 769         wcp->data_size = 0;
 770
 771         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 772
 773         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 774                 fsp->fd, (double)wcp->offset, (unsigned int)data_size));
 775
 776 #ifdef WITH_PROFILE
 777         if(data_size == wcp->alloc_size) {
 778                 DO_PROFILE_INC(writecache_num_perfect_writes);
 779         }
 780 #endif
 781
 782         ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
 783
 784         /*
 785          * Ensure file size if kept up to date if write extends file.
 786          */
 787
 788         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
 789                 wcp->file_size = wcp->offset + ret;
 790         }
 791
 792         return ret;
 793 }
 794
 795 /*******************************************************************
 796 sync a file
 797 ********************************************************************/
 798
 799 void sync_file(connection_struct *conn, files_struct *fsp)
 800 {
 801         if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
 802                 flush_write_cache(fsp, SYNC_FLUSH);
 803                 SMB_VFS_FSYNC(fsp,fsp->fd);
 804         }
 805 }
 806
 807
 808 /************************************************************
 809  Perform a stat whether a valid fd or not.
 810 ************************************************************/
 811
 812 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
 813 {
 814         if (fsp->fd == -1) {
 815                 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
 816         } else {
 817                 return SMB_VFS_FSTAT(fsp,fsp->fd, pst);
 818         }
 819 }