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
  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                         /* If we didn't get the "set modtime" call ourselves, we must
 147                            store the last write time to restore on close. JRA. */
 148                         if (!fsp->pending_modtime_owner) {
 149                                 fsp->last_write_time = time(NULL);
 150                         }
 151                 }
 152
 153 /* Yes - this is correct - writes don't update this. JRA. */
 154 /* Found by Samba4 tests. */
 155 #if 0
 156                 fsp->position_information = fsp->pos;
 157 #endif
 158         }
 159
 160         return ret;
 161 }
 162
 163 /****************************************************************************
 164 write to a file
 165 ****************************************************************************/
 166
 167 ssize_t write_file(files_struct *fsp, char *data, SMB_OFF_T pos, size_t n)
 168 {
 169         write_cache *wcp = fsp->wcp;
 170         ssize_t total_written = 0;
 171         int write_path = -1;
 172
 173         if (fsp->print_file) {
 174                 fstring sharename;
 175                 uint32 jobid;
 176
 177                 if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
 178                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
 179                                                 (unsigned int)fsp->rap_print_jobid ));
 180                         errno = EBADF;
 181                         return -1;
 182                 }
 183
 184                 return print_job_write(SNUM(fsp->conn), jobid, data, n);
 185         }
 186
 187         if (!fsp->can_write) {
 188                 errno = EPERM;
 189                 return(0);
 190         }
 191
 192         if (!fsp->modified) {
 193                 SMB_STRUCT_STAT st;
 194                 fsp->modified = True;
 195
 196                 if (SMB_VFS_FSTAT(fsp,fsp->fd,&st) == 0) {
 197                         int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
 198                         fsp->size = (SMB_BIG_UINT)st.st_size;
 199                         if ((lp_store_dos_attributes(SNUM(fsp->conn)) || MAP_ARCHIVE(fsp->conn)) && !IS_DOS_ARCHIVE(dosmode)) {
 200                                 file_set_dosmode(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st, False);
 201                         }
 202
 203                         /*
 204                          * If this is the first write and we have an exclusive oplock then setup
 205                          * the write cache.
 206                          */
 207
 208                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
 209                                 setup_write_cache(fsp, st.st_size);
 210                                 wcp = fsp->wcp;
 211                         }
 212                 }
 213         }
 214
 215 #ifdef WITH_PROFILE
 216         DO_PROFILE_INC(writecache_total_writes);
 217         if (!fsp->oplock_type) {
 218                 DO_PROFILE_INC(writecache_non_oplock_writes);
 219         }
 220 #endif
 221
 222         /*
 223          * If this file is level II oplocked then we need
 224          * to grab the shared memory lock and inform all
 225          * other files with a level II lock that they need
 226          * to flush their read caches. We keep the lock over
 227          * the shared memory area whilst doing this.
 228          */
 229
 230         release_level_2_oplocks_on_change(fsp);
 231
 232 #ifdef WITH_PROFILE
 233         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
 234                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
 235 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
 236                         profile_p->writecache_init_writes,
 237                         profile_p->writecache_abutted_writes,
 238                         profile_p->writecache_total_writes,
 239                         profile_p->writecache_non_oplock_writes,
 240                         profile_p->writecache_allocated_write_caches,
 241                         profile_p->writecache_num_write_caches,
 242                         profile_p->writecache_direct_writes,
 243                         profile_p->writecache_num_perfect_writes,
 244                         profile_p->writecache_read_hits ));
 245
 246                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
 247                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
 248                         profile_p->writecache_flushed_writes[READ_FLUSH],
 249                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
 250                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
 251                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
 252                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
 253                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
 254         }
 255 #endif
 256
 257         if(!wcp) {
 258                 DO_PROFILE_INC(writecache_direct_writes);
 259                 total_written = real_write_file(fsp, data, pos, n);
 260                 if ((total_written != -1) && (pos + total_written > (SMB_OFF_T)fsp->size))
 261                         fsp->size = (SMB_BIG_UINT)(pos + total_written);
 262                 return total_written;
 263         }
 264
 265         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
 266                 fsp->fsp_name, fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
 267
 268         fsp->pos = pos + n;
 269
 270         /*
 271          * If we have active cache and it isn't contiguous then we flush.
 272          * NOTE: There is a small problem with running out of disk ....
 273          */
 274
 275         if (wcp->data_size) {
 276
 277                 BOOL cache_flush_needed = False;
 278
 279                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 280
 281                         /* ASCII art.... JRA.
 282
 283       +--------------+-----
 284       | Cached data  | Rest of allocated cache buffer....
 285       +--------------+-----
 286
 287             +-------------------+
 288             | Data to write     |
 289             +-------------------+
 290
 291                         */
 292
 293                         /*
 294                          * Start of write overlaps or abutts the existing data.
 295                          */
 296
 297                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 298
 299                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 300
 301                         /*
 302                          * Update the current buffer size with the new data.
 303                          */
 304
 305                         if(pos + data_used > wcp->offset + wcp->data_size)
 306                                 wcp->data_size = pos + data_used - wcp->offset;
 307
 308                         /*
 309                          * Update the file size if changed.
 310                          */
 311
 312                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 313                                 wcp->file_size = wcp->offset + wcp->data_size;
 314                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 315                         }
 316
 317                         /*
 318                          * If we used all the data then
 319                          * return here.
 320                          */
 321
 322                         if(n == data_used)
 323                                 return n;
 324                         else
 325                                 cache_flush_needed = True;
 326
 327                         /*
 328                          * Move the start of data forward by the amount used,
 329                          * cut down the amount left by the same amount.
 330                          */
 331
 332                         data += data_used;
 333                         pos += data_used;
 334                         n -= data_used;
 335
 336                         DO_PROFILE_INC(writecache_abutted_writes);
 337                         total_written = data_used;
 338
 339                         write_path = 1;
 340
 341                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 342                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 343
 344                         /* ASCII art.... JRA.
 345
 346                         +---------------+
 347                         | Cache buffer  |
 348                         +---------------+
 349
 350             +-------------------+
 351             | Data to write     |
 352             +-------------------+
 353
 354                         */
 355
 356                         /*
 357                          * End of write overlaps the existing data.
 358                          */
 359
 360                         size_t data_used = pos + n - wcp->offset;
 361
 362                         memcpy(wcp->data, data + n - data_used, data_used);
 363
 364                         /*
 365                          * Update the current buffer size with the new data.
 366                          */
 367
 368                         if(pos + n > wcp->offset + wcp->data_size)
 369                                 wcp->data_size = pos + n - wcp->offset;
 370
 371                         /*
 372                          * Update the file size if changed.
 373                          */
 374
 375                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 376                                 wcp->file_size = wcp->offset + wcp->data_size;
 377                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 378                         }
 379
 380                         /*
 381                          * We don't need to move the start of data, but we
 382                          * cut down the amount left by the amount used.
 383                          */
 384
 385                         n -= data_used;
 386
 387                         /*
 388                          * We cannot have used all the data here.
 389                          */
 390
 391                         cache_flush_needed = True;
 392
 393                         DO_PROFILE_INC(writecache_abutted_writes);
 394                         total_written = data_used;
 395
 396                         write_path = 2;
 397
 398                 } else if ( (pos >= wcp->file_size) &&
 399                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 400                                         (pos > wcp->offset + wcp->data_size) &&
 401                                         (pos < wcp->offset + wcp->alloc_size) ) {
 402
 403                         /* ASCII art.... JRA.
 404
 405                        End of file ---->|
 406
 407                         +---------------+---------------+
 408                         | Cached data   | Cache buffer  |
 409                         +---------------+---------------+
 410
 411                                               +-------------------+
 412                                               | Data to write     |
 413                                               +-------------------+
 414
 415                         */
 416
 417                         /*
 418                          * Non-contiguous write part of which fits within
 419                          * the cache buffer and is extending the file
 420                          * and the cache contents reflect the current
 421                          * data up to the current end of the file.
 422                          */
 423
 424                         size_t data_used;
 425
 426                         if(pos + n <= wcp->offset + wcp->alloc_size)
 427                                 data_used = n;
 428                         else
 429                                 data_used = wcp->offset + wcp->alloc_size - pos;
 430
 431                         /*
 432                          * Fill in the non-continuous area with zeros.
 433                          */
 434
 435                         memset(wcp->data + wcp->data_size, '\0',
 436                                 pos - (wcp->offset + wcp->data_size) );
 437
 438                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 439
 440                         /*
 441                          * Update the current buffer size with the new data.
 442                          */
 443
 444                         if(pos + data_used > wcp->offset + wcp->data_size)
 445                                 wcp->data_size = pos + data_used - wcp->offset;
 446
 447                         /*
 448                          * Update the file size if changed.
 449                          */
 450
 451                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 452                                 wcp->file_size = wcp->offset + wcp->data_size;
 453                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 454                         }
 455
 456                         /*
 457                          * If we used all the data then
 458                          * return here.
 459                          */
 460
 461                         if(n == data_used)
 462                                 return n;
 463                         else
 464                                 cache_flush_needed = True;
 465
 466                         /*
 467                          * Move the start of data forward by the amount used,
 468                          * cut down the amount left by the same amount.
 469                          */
 470
 471                         data += data_used;
 472                         pos += data_used;
 473                         n -= data_used;
 474
 475                         DO_PROFILE_INC(writecache_abutted_writes);
 476                         total_written = data_used;
 477
 478                         write_path = 3;
 479
 480                 } else {
 481
 482                         /* ASCII art..... JRA.
 483
 484    Case 1).
 485
 486                         +---------------+---------------+
 487                         | Cached data   | Cache buffer  |
 488                         +---------------+---------------+
 489
 490                                                               +-------------------+
 491                                                               | Data to write     |
 492                                                               +-------------------+
 493
 494    Case 2).
 495
 496                            +---------------+---------------+
 497                            | Cached data   | Cache buffer  |
 498                            +---------------+---------------+
 499
 500    +-------------------+
 501    | Data to write     |
 502    +-------------------+
 503
 504     Case 3).
 505
 506                            +---------------+---------------+
 507                            | Cached data   | Cache buffer  |
 508                            +---------------+---------------+
 509
 510                   +-----------------------------------------------------+
 511                   | Data to write                                       |
 512                   +-----------------------------------------------------+
 513
 514                   */
 515
 516                         /*
 517                          * Write is bigger than buffer, or there is no overlap on the
 518                          * low or high ends.
 519                          */
 520
 521                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 522 len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 523
 524                         /*
 525                          * Update the file size if needed.
 526                          */
 527
 528                         if(pos + n > wcp->file_size) {
 529                                 wcp->file_size = pos + n;
 530                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 531                         }
 532
 533                         /*
 534                          * If write would fit in the cache, and is larger than
 535                          * the data already in the cache, flush the cache and
 536                          * preferentially copy the data new data into it. Otherwise
 537                          * just write the data directly.
 538                          */
 539
 540                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 541                                 cache_flush_needed = True;
 542                         } else {
 543                                 ssize_t ret = real_write_file(fsp, data, pos, n);
 544
 545                                 /*
 546                                  * If the write overlaps the entire cache, then
 547                                  * discard the current contents of the cache.
 548                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 549                                  */
 550
 551                                 if ((pos <= wcp->offset) &&
 552                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 553                                         DEBUG(9,("write_file: discarding overwritten write \
 554 cache: fd = %d, off=%.0f, size=%u\n", fsp->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 555                                         wcp->data_size = 0;
 556                                 }
 557
 558                                 DO_PROFILE_INC(writecache_direct_writes);
 559                                 if (ret == -1)
 560                                         return ret;
 561
 562                                 if (pos + ret > wcp->file_size) {
 563                                         wcp->file_size = pos + ret;
 564                                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 565                                 }
 566
 567                                 return ret;
 568                         }
 569
 570                         write_path = 4;
 571
 572                 }
 573
 574                 if(wcp->data_size > wcp->file_size) {
 575                         wcp->file_size = wcp->data_size;
 576                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 577                 }
 578
 579                 if (cache_flush_needed) {
 580                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 581 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 582                                 write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 583                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 584
 585                         flush_write_cache(fsp, WRITE_FLUSH);
 586                 }
 587         }
 588
 589         /*
 590          * If the write request is bigger than the cache
 591          * size, write it all out.
 592          */
 593
 594         if (n > wcp->alloc_size ) {
 595                 ssize_t ret = real_write_file(fsp, data, pos, n);
 596                 if (ret == -1)
 597                         return -1;
 598
 599                 if (pos + ret > wcp->file_size) {
 600                         wcp->file_size = pos + n;
 601                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 602                 }
 603
 604                 DO_PROFILE_INC(writecache_direct_writes);
 605                 return total_written + n;
 606         }
 607
 608         /*
 609          * If there's any data left, cache it.
 610          */
 611
 612         if (n) {
 613 #ifdef WITH_PROFILE
 614                 if (wcp->data_size) {
 615                         DO_PROFILE_INC(writecache_abutted_writes);
 616                 } else {
 617                         DO_PROFILE_INC(writecache_init_writes);
 618                 }
 619 #endif
 620                 memcpy(wcp->data+wcp->data_size, data, n);
 621                 if (wcp->data_size == 0) {
 622                         wcp->offset = pos;
 623                         DO_PROFILE_INC(writecache_num_write_caches);
 624                 }
 625                 wcp->data_size += n;
 626
 627                 /*
 628                  * Update the file size if changed.
 629                  */
 630
 631                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 632                         wcp->file_size = wcp->offset + wcp->data_size;
 633                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 634                 }
 635                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 636                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 637
 638                 total_written += n;
 639                 return total_written; /* .... that's a write :) */
 640         }
 641
 642         return total_written;
 643 }
 644
 645 /****************************************************************************
 646  Delete the write cache structure.
 647 ****************************************************************************/
 648
 649 void delete_write_cache(files_struct *fsp)
 650 {
 651         write_cache *wcp;
 652
 653         if(!fsp)
 654                 return;
 655
 656         if(!(wcp = fsp->wcp))
 657                 return;
 658
 659         DO_PROFILE_DEC(writecache_allocated_write_caches);
 660         allocated_write_caches--;
 661
 662         SMB_ASSERT(wcp->data_size == 0);
 663
 664         SAFE_FREE(wcp->data);
 665         SAFE_FREE(fsp->wcp);
 666
 667         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
 668 }
 669
 670 /****************************************************************************
 671  Setup the write cache structure.
 672 ****************************************************************************/
 673
 674 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 675 {
 676         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 677         write_cache *wcp;
 678
 679         if (allocated_write_caches >= MAX_WRITE_CACHES)
 680                 return False;
 681
 682         if(alloc_size == 0 || fsp->wcp)
 683                 return False;
 684
 685         if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
 686                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 687                 return False;
 688         }
 689
 690         wcp->file_size = file_size;
 691         wcp->offset = 0;
 692         wcp->alloc_size = alloc_size;
 693         wcp->data_size = 0;
 694         if((wcp->data = SMB_MALLOC(wcp->alloc_size)) == NULL) {
 695                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 696                         (unsigned int)wcp->alloc_size ));
 697                 SAFE_FREE(wcp);
 698                 return False;
 699         }
 700
 701         memset(wcp->data, '\0', wcp->alloc_size );
 702
 703         fsp->wcp = wcp;
 704         DO_PROFILE_INC(writecache_allocated_write_caches);
 705         allocated_write_caches++;
 706
 707         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 708                 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
 709
 710         return True;
 711 }
 712
 713 /****************************************************************************
 714  Cope with a size change.
 715 ****************************************************************************/
 716
 717 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 718 {
 719         fsp->size = (SMB_BIG_UINT)file_size;
 720         if(fsp->wcp) {
 721                 /* The cache *must* have been flushed before we do this. */
 722                 if (fsp->wcp->data_size != 0) {
 723                         pstring msg;
 724                         slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
 725 on file %s with write cache size = %lu\n", fsp->fsp_name, (unsigned long)fsp->wcp->data_size );
 726                         smb_panic(msg);
 727                 }
 728                 fsp->wcp->file_size = file_size;
 729         }
 730 }
 731
 732 /*******************************************************************
 733  Flush a write cache struct to disk.
 734 ********************************************************************/
 735
 736 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 737 {
 738         write_cache *wcp = fsp->wcp;
 739         size_t data_size;
 740         ssize_t ret;
 741
 742         if(!wcp || !wcp->data_size)
 743                 return 0;
 744
 745         data_size = wcp->data_size;
 746         wcp->data_size = 0;
 747
 748         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 749
 750         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 751                 fsp->fd, (double)wcp->offset, (unsigned int)data_size));
 752
 753 #ifdef WITH_PROFILE
 754         if(data_size == wcp->alloc_size)
 755                 DO_PROFILE_INC(writecache_num_perfect_writes);
 756 #endif
 757
 758         ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
 759
 760         /*
 761          * Ensure file size if kept up to date if write extends file.
 762          */
 763
 764         if ((ret != -1) && (wcp->offset + ret > wcp->file_size))
 765                 wcp->file_size = wcp->offset + ret;
 766
 767         return ret;
 768 }
 769
 770 /*******************************************************************
 771 sync a file
 772 ********************************************************************/
 773
 774 void sync_file(connection_struct *conn, files_struct *fsp)
 775 {
 776         if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
 777                 flush_write_cache(fsp, SYNC_FLUSH);
 778                 SMB_VFS_FSYNC(fsp,fsp->fd);
 779         }
 780 }
 781
 782
 783 /************************************************************
 784  Perform a stat whether a valid fd or not.
 785 ************************************************************/
 786
 787 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
 788 {
 789         if (fsp->fd == -1)
 790                 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
 791         else
 792                 return SMB_VFS_FSTAT(fsp,fsp->fd, pst);
 793 }