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