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  Seek a file. Try to avoid the seek if possible.
  29 ****************************************************************************/
  30
  31 static SMB_OFF_T seek_file(files_struct *fsp,SMB_OFF_T pos)
  32 {
  33         SMB_OFF_T seek_ret;
  34
  35         seek_ret = fsp->conn->vfs_ops.lseek(fsp,fsp->fd,pos,SEEK_SET);
  36
  37         if(seek_ret == -1) {
  38                 DEBUG(0,("seek_file: (%s) sys_lseek failed. Error was %s\n",
  39                         fsp->fsp_name, strerror(errno) ));
  40                 fsp->pos = -1;
  41                 return -1;
  42         }
  43
  44         fsp->pos = seek_ret;
  45
  46         DEBUG(10,("seek_file (%s): requested pos = %.0f, new pos = %.0f\n",
  47                 fsp->fsp_name, (double)pos, (double)fsp->pos ));
  48
  49         return(fsp->pos);
  50 }
  51
  52 /****************************************************************************
  53  Read from write cache if we can.
  54 ****************************************************************************/
  55
  56
  57 static BOOL read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  58 {
  59         write_cache *wcp = fsp->wcp;
  60
  61         if(!wcp)
  62                 return False;
  63
  64         if(n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size)
  65                 return False;
  66
  67         memcpy(data, wcp->data + (pos - wcp->offset), n);
  68
  69         DO_PROFILE_INC(writecache_read_hits);
  70
  71         return True;
  72 }
  73
  74 /****************************************************************************
  75  Read from a file.
  76 ****************************************************************************/
  77
  78 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  79 {
  80         ssize_t ret=0,readret;
  81
  82         /* you can't read from print files */
  83         if (fsp->print_file)
  84                 return -1;
  85
  86         /*
  87          * Serve from write cache if we can.
  88          */
  89
  90         if(read_from_write_cache(fsp, data, pos, n))
  91                 return n;
  92
  93         flush_write_cache(fsp, READ_FLUSH);
  94
  95         if (seek_file(fsp,pos) == -1) {
  96                 DEBUG(3,("read_file: Failed to seek to %.0f\n",(double)pos));
  97                 return(ret);
  98         }
  99
 100         if (n > 0) {
 101 #ifdef DMF_FIX
 102                 int numretries = 3;
 103 tryagain:
 104                 readret = fsp->conn->vfs_ops.read(fsp,fsp->fd,data,n);
 105                 if (readret == -1) {
 106                         if ((errno == EAGAIN) && numretries) {
 107                                 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
 108                                 (void)sleep(10);
 109                                 --numretries;
 110                                 goto tryagain;
 111                         }
 112                         return -1;
 113                 }
 114 #else /* NO DMF fix. */
 115                 readret = fsp->conn->vfs_ops.read(fsp,fsp->fd,data,n);
 116                 if (readret == -1)
 117                         return -1;
 118 #endif
 119                 if (readret > 0)
 120                         ret += readret;
 121         }
 122
 123         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
 124                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 125
 126         return(ret);
 127 }
 128
 129 /* how many write cache buffers have been allocated */
 130 static unsigned int allocated_write_caches;
 131
 132 /****************************************************************************
 133  *Really* write to a file.
 134 ****************************************************************************/
 135
 136 static ssize_t real_write_file(files_struct *fsp,char *data,SMB_OFF_T pos, size_t n)
 137 {
 138         ssize_t ret;
 139
 140         if ((pos != -1) && (seek_file(fsp,pos) == -1))
 141                 return -1;
 142
 143         ret = vfs_write_data(fsp,data,n);
 144
 145         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 146                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 147
 148         return ret;
 149 }
 150
 151 /****************************************************************************
 152 write to a file
 153 ****************************************************************************/
 154
 155 ssize_t write_file(files_struct *fsp, char *data, SMB_OFF_T pos, size_t n)
 156 {
 157         write_cache *wcp = fsp->wcp;
 158         ssize_t total_written = 0;
 159         int write_path = -1;
 160
 161         if (fsp->print_file) {
 162                 int snum;
 163                 uint32 jobid;
 164
 165                 if (!rap_to_pjobid(fsp->rap_print_jobid, &snum, &jobid)) {
 166                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
 167                                                 (unsigned int)fsp->rap_print_jobid ));
 168                         errno = EBADF;
 169                         return -1;
 170                 }
 171
 172                 return print_job_write(SNUM(fsp->conn), jobid, data, n);
 173         }
 174
 175         if (!fsp->can_write) {
 176                 errno = EPERM;
 177                 return(0);
 178         }
 179
 180         if (!fsp->modified) {
 181                 SMB_STRUCT_STAT st;
 182                 fsp->modified = True;
 183
 184                 if (fsp->conn->vfs_ops.fstat(fsp,fsp->fd,&st) == 0) {
 185                         int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
 186                         fsp->size = (SMB_BIG_UINT)st.st_size;
 187                         if (MAP_ARCHIVE(fsp->conn) && !IS_DOS_ARCHIVE(dosmode))
 188                                 file_chmod(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st);
 189
 190                         /*
 191                          * If this is the first write and we have an exclusive oplock then setup
 192                          * the write cache.
 193                          */
 194
 195                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
 196                                 setup_write_cache(fsp, st.st_size);
 197                                 wcp = fsp->wcp;
 198                         }
 199                 }
 200         }
 201
 202 #ifdef WITH_PROFILE
 203         DO_PROFILE_INC(writecache_total_writes);
 204         if (!fsp->oplock_type) {
 205                 DO_PROFILE_INC(writecache_non_oplock_writes);
 206         }
 207 #endif
 208
 209         /*
 210          * If this file is level II oplocked then we need
 211          * to grab the shared memory lock and inform all
 212          * other files with a level II lock that they need
 213          * to flush their read caches. We keep the lock over
 214          * the shared memory area whilst doing this.
 215          */
 216
 217         release_level_2_oplocks_on_change(fsp);
 218
 219 #ifdef WITH_PROFILE
 220         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
 221                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
 222 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
 223                         profile_p->writecache_init_writes,
 224                         profile_p->writecache_abutted_writes,
 225                         profile_p->writecache_total_writes,
 226                         profile_p->writecache_non_oplock_writes,
 227                         profile_p->writecache_allocated_write_caches,
 228                         profile_p->writecache_num_write_caches,
 229                         profile_p->writecache_direct_writes,
 230                         profile_p->writecache_num_perfect_writes,
 231                         profile_p->writecache_read_hits ));
 232
 233                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
 234                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
 235                         profile_p->writecache_flushed_writes[READ_FLUSH],
 236                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
 237                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
 238                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
 239                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
 240                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
 241         }
 242 #endif
 243
 244         if(!wcp) {
 245                 DO_PROFILE_INC(writecache_direct_writes);
 246                 total_written = real_write_file(fsp, data, pos, n);
 247                 if ((total_written != -1) && (pos + total_written > (SMB_OFF_T)fsp->size))
 248                         fsp->size = (SMB_BIG_UINT)(pos + total_written);
 249                 return total_written;
 250         }
 251
 252         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
 253                 fsp->fsp_name, fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
 254
 255         /*
 256          * If we have active cache and it isn't contiguous then we flush.
 257          * NOTE: There is a small problem with running out of disk ....
 258          */
 259
 260         if (wcp->data_size) {
 261
 262                 BOOL cache_flush_needed = False;
 263
 264                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 265
 266                         /* ASCII art.... JRA.
 267
 268       +--------------+-----
 269       | Cached data  | Rest of allocated cache buffer....
 270       +--------------+-----
 271
 272             +-------------------+
 273             | Data to write     |
 274             +-------------------+
 275
 276                         */
 277
 278                         /*
 279                          * Start of write overlaps or abutts the existing data.
 280                          */
 281
 282                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 283
 284                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 285
 286                         /*
 287                          * Update the current buffer size with the new data.
 288                          */
 289
 290                         if(pos + data_used > wcp->offset + wcp->data_size)
 291                                 wcp->data_size = pos + data_used - wcp->offset;
 292
 293                         /*
 294                          * Update the file size if changed.
 295                          */
 296
 297                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 298                                 wcp->file_size = wcp->offset + wcp->data_size;
 299                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 300                         }
 301
 302                         /*
 303                          * If we used all the data then
 304                          * return here.
 305                          */
 306
 307                         if(n == data_used)
 308                                 return n;
 309                         else
 310                                 cache_flush_needed = True;
 311
 312                         /*
 313                          * Move the start of data forward by the amount used,
 314                          * cut down the amount left by the same amount.
 315                          */
 316
 317                         data += data_used;
 318                         pos += data_used;
 319                         n -= data_used;
 320
 321                         DO_PROFILE_INC(writecache_abutted_writes);
 322                         total_written = data_used;
 323
 324                         write_path = 1;
 325
 326                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 327                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 328
 329                         /* ASCII art.... JRA.
 330
 331                         +---------------+
 332                         | Cache buffer  |
 333                         +---------------+
 334
 335             +-------------------+
 336             | Data to write     |
 337             +-------------------+
 338
 339                         */
 340
 341                         /*
 342                          * End of write overlaps the existing data.
 343                          */
 344
 345                         size_t data_used = pos + n - wcp->offset;
 346
 347                         memcpy(wcp->data, data + n - data_used, data_used);
 348
 349                         /*
 350                          * Update the current buffer size with the new data.
 351                          */
 352
 353                         if(pos + n > wcp->offset + wcp->data_size)
 354                                 wcp->data_size = pos + n - wcp->offset;
 355
 356                         /*
 357                          * Update the file size if changed.
 358                          */
 359
 360                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 361                                 wcp->file_size = wcp->offset + wcp->data_size;
 362                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 363                         }
 364
 365                         /*
 366                          * We don't need to move the start of data, but we
 367                          * cut down the amount left by the amount used.
 368                          */
 369
 370                         n -= data_used;
 371
 372                         /*
 373                          * We cannot have used all the data here.
 374                          */
 375
 376                         cache_flush_needed = True;
 377
 378                         DO_PROFILE_INC(writecache_abutted_writes);
 379                         total_written = data_used;
 380
 381                         write_path = 2;
 382
 383                 } else if ( (pos >= wcp->file_size) &&
 384                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 385                                         (pos > wcp->offset + wcp->data_size) &&
 386                                         (pos < wcp->offset + wcp->alloc_size) ) {
 387
 388                         /* ASCII art.... JRA.
 389
 390                        End of file ---->|
 391
 392                         +---------------+---------------+
 393                         | Cached data   | Cache buffer  |
 394                         +---------------+---------------+
 395
 396                                               +-------------------+
 397                                               | Data to write     |
 398                                               +-------------------+
 399
 400                         */
 401
 402                         /*
 403                          * Non-contiguous write part of which fits within
 404                          * the cache buffer and is extending the file
 405                          * and the cache contents reflect the current
 406                          * data up to the current end of the file.
 407                          */
 408
 409                         size_t data_used;
 410
 411                         if(pos + n <= wcp->offset + wcp->alloc_size)
 412                                 data_used = n;
 413                         else
 414                                 data_used = wcp->offset + wcp->alloc_size - pos;
 415
 416                         /*
 417                          * Fill in the non-continuous area with zeros.
 418                          */
 419
 420                         memset(wcp->data + wcp->data_size, '\0',
 421                                 pos - (wcp->offset + wcp->data_size) );
 422
 423                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 424
 425                         /*
 426                          * Update the current buffer size with the new data.
 427                          */
 428
 429                         if(pos + data_used > wcp->offset + wcp->data_size)
 430                                 wcp->data_size = pos + data_used - wcp->offset;
 431
 432                         /*
 433                          * Update the file size if changed.
 434                          */
 435
 436                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 437                                 wcp->file_size = wcp->offset + wcp->data_size;
 438                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 439                         }
 440
 441                         /*
 442                          * If we used all the data then
 443                          * return here.
 444                          */
 445
 446                         if(n == data_used)
 447                                 return n;
 448                         else
 449                                 cache_flush_needed = True;
 450
 451                         /*
 452                          * Move the start of data forward by the amount used,
 453                          * cut down the amount left by the same amount.
 454                          */
 455
 456                         data += data_used;
 457                         pos += data_used;
 458                         n -= data_used;
 459
 460                         DO_PROFILE_INC(writecache_abutted_writes);
 461                         total_written = data_used;
 462
 463                         write_path = 3;
 464
 465                 } else {
 466
 467                         /* ASCII art..... JRA.
 468
 469    Case 1).
 470
 471                         +---------------+---------------+
 472                         | Cached data   | Cache buffer  |
 473                         +---------------+---------------+
 474
 475                                                               +-------------------+
 476                                                               | Data to write     |
 477                                                               +-------------------+
 478
 479    Case 2).
 480
 481                            +---------------+---------------+
 482                            | Cached data   | Cache buffer  |
 483                            +---------------+---------------+
 484
 485    +-------------------+
 486    | Data to write     |
 487    +-------------------+
 488
 489     Case 3).
 490
 491                            +---------------+---------------+
 492                            | Cached data   | Cache buffer  |
 493                            +---------------+---------------+
 494
 495                   +-----------------------------------------------------+
 496                   | Data to write                                       |
 497                   +-----------------------------------------------------+
 498
 499                   */
 500
 501                         /*
 502                          * Write is bigger than buffer, or there is no overlap on the
 503                          * low or high ends.
 504                          */
 505
 506                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 507 len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 508
 509                         /*
 510                          * Update the file size if needed.
 511                          */
 512
 513                         if(pos + n > wcp->file_size) {
 514                                 wcp->file_size = pos + n;
 515                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 516                         }
 517
 518                         /*
 519                          * If write would fit in the cache, and is larger than
 520                          * the data already in the cache, flush the cache and
 521                          * preferentially copy the data new data into it. Otherwise
 522                          * just write the data directly.
 523                          */
 524
 525                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 526                                 cache_flush_needed = True;
 527                         } else {
 528                                 ssize_t ret = real_write_file(fsp, data, pos, n);
 529
 530                                 /*
 531                                  * If the write overlaps the entire cache, then
 532                                  * discard the current contents of the cache.
 533                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 534                                  */
 535
 536                                 if ((pos <= wcp->offset) &&
 537                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 538                                         DEBUG(9,("write_file: discarding overwritten write \
 539 cache: fd = %d, off=%.0f, size=%u\n", fsp->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 540                                         wcp->data_size = 0;
 541                                 }
 542
 543                                 DO_PROFILE_INC(writecache_direct_writes);
 544                                 if (ret == -1)
 545                                         return ret;
 546
 547                                 if (pos + ret > wcp->file_size) {
 548                                         wcp->file_size = pos + ret;
 549                                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 550                                 }
 551
 552                                 return ret;
 553                         }
 554
 555                         write_path = 4;
 556
 557                 }
 558
 559                 if(wcp->data_size > wcp->file_size) {
 560                         wcp->file_size = wcp->data_size;
 561                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 562                 }
 563
 564                 if (cache_flush_needed) {
 565                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 566 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 567                                 write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 568                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 569
 570                         flush_write_cache(fsp, WRITE_FLUSH);
 571                 }
 572         }
 573
 574         /*
 575          * If the write request is bigger than the cache
 576          * size, write it all out.
 577          */
 578
 579         if (n > wcp->alloc_size ) {
 580                 ssize_t ret = real_write_file(fsp, data, pos, n);
 581                 if (ret == -1)
 582                         return -1;
 583
 584                 if (pos + ret > wcp->file_size) {
 585                         wcp->file_size = pos + n;
 586                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 587                 }
 588
 589                 DO_PROFILE_INC(writecache_direct_writes);
 590                 return total_written + n;
 591         }
 592
 593         /*
 594          * If there's any data left, cache it.
 595          */
 596
 597         if (n) {
 598 #ifdef WITH_PROFILE
 599                 if (wcp->data_size) {
 600                         DO_PROFILE_INC(writecache_abutted_writes);
 601                 } else {
 602                         DO_PROFILE_INC(writecache_init_writes);
 603                 }
 604 #endif
 605                 memcpy(wcp->data+wcp->data_size, data, n);
 606                 if (wcp->data_size == 0) {
 607                         wcp->offset = pos;
 608                         DO_PROFILE_INC(writecache_num_write_caches);
 609                 }
 610                 wcp->data_size += n;
 611
 612                 /*
 613                  * Update the file size if changed.
 614                  */
 615
 616                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 617                         wcp->file_size = wcp->offset + wcp->data_size;
 618                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 619                 }
 620                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 621                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 622
 623                 total_written += n;
 624                 return total_written; /* .... that's a write :) */
 625         }
 626
 627         return total_written;
 628 }
 629
 630 /****************************************************************************
 631  Delete the write cache structure.
 632 ****************************************************************************/
 633
 634 void delete_write_cache(files_struct *fsp)
 635 {
 636         write_cache *wcp;
 637
 638         if(!fsp)
 639                 return;
 640
 641         if(!(wcp = fsp->wcp))
 642                 return;
 643
 644         DO_PROFILE_DEC(writecache_allocated_write_caches);
 645         allocated_write_caches--;
 646
 647         SMB_ASSERT(wcp->data_size == 0);
 648
 649         SAFE_FREE(wcp->data);
 650         SAFE_FREE(fsp->wcp);
 651
 652         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
 653 }
 654
 655 /****************************************************************************
 656  Setup the write cache structure.
 657 ****************************************************************************/
 658
 659 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 660 {
 661         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 662         write_cache *wcp;
 663
 664         if (allocated_write_caches >= MAX_WRITE_CACHES)
 665                 return False;
 666
 667         if(alloc_size == 0 || fsp->wcp)
 668                 return False;
 669
 670         if((wcp = (write_cache *)malloc(sizeof(write_cache))) == NULL) {
 671                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 672                 return False;
 673         }
 674
 675         wcp->file_size = file_size;
 676         wcp->offset = 0;
 677         wcp->alloc_size = alloc_size;
 678         wcp->data_size = 0;
 679         if((wcp->data = malloc(wcp->alloc_size)) == NULL) {
 680                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 681                         (unsigned int)wcp->alloc_size ));
 682                 SAFE_FREE(wcp);
 683                 return False;
 684         }
 685
 686         memset(wcp->data, '\0', wcp->alloc_size );
 687
 688         fsp->wcp = wcp;
 689         DO_PROFILE_INC(writecache_allocated_write_caches);
 690         allocated_write_caches++;
 691
 692         DEBUG(10,("setup_write_cache: File %s allocated write cache size %u\n",
 693                 fsp->fsp_name, wcp->alloc_size ));
 694
 695         return True;
 696 }
 697
 698 /****************************************************************************
 699  Cope with a size change.
 700 ****************************************************************************/
 701
 702 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 703 {
 704         fsp->size = (SMB_BIG_UINT)file_size;
 705         if(fsp->wcp) {
 706                 /* The cache *must* have been flushed before we do this. */
 707                 if (fsp->wcp->data_size != 0) {
 708                         pstring msg;
 709                         slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
 710 on file %s with write cache size = %u\n", fsp->fsp_name, fsp->wcp->data_size );
 711                         smb_panic(msg);
 712                 }
 713                 fsp->wcp->file_size = file_size;
 714         }
 715 }
 716
 717 /*******************************************************************
 718  Flush a write cache struct to disk.
 719 ********************************************************************/
 720
 721 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 722 {
 723         write_cache *wcp = fsp->wcp;
 724         size_t data_size;
 725         ssize_t ret;
 726
 727         if(!wcp || !wcp->data_size)
 728                 return 0;
 729
 730         data_size = wcp->data_size;
 731         wcp->data_size = 0;
 732
 733         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 734
 735         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 736                 fsp->fd, (double)wcp->offset, (unsigned int)data_size));
 737
 738 #ifdef WITH_PROFILE
 739         if(data_size == wcp->alloc_size)
 740                 DO_PROFILE_INC(writecache_num_perfect_writes);
 741 #endif
 742
 743         ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
 744
 745         /*
 746          * Ensure file size if kept up to date if write extends file.
 747          */
 748
 749         if ((ret != -1) && (wcp->offset + ret > wcp->file_size))
 750                 wcp->file_size = wcp->offset + ret;
 751
 752         return ret;
 753 }
 754
 755 /*******************************************************************
 756 sync a file
 757 ********************************************************************/
 758
 759 void sync_file(connection_struct *conn, files_struct *fsp)
 760 {
 761         if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
 762                 flush_write_cache(fsp, SYNC_FLUSH);
 763                 conn->vfs_ops.fsync(fsp,fsp->fd);
 764         }
 765 }
 766
 767
 768 /************************************************************
 769  Perform a stat whether a valid fd or not.
 770 ************************************************************/
 771
 772 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
 773 {
 774         if (fsp->fd == -1)
 775                 return vfs_stat(fsp->conn, fsp->fsp_name, pst);
 776         else
 777                 return vfs_fstat(fsp,fsp->fd, pst);
 778 }