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 = SMB_VFS_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                 fsp->pos = pos + n;
  92                 fsp->position_information = fsp->pos;
  93                 return n;
  94         }
  95
  96         flush_write_cache(fsp, READ_FLUSH);
  97
  98         fsp->pos = pos;
  99
 100         if (n > 0) {
 101 #ifdef DMF_FIX
 102                 int numretries = 3;
 103 tryagain:
 104                 readret = SMB_VFS_PREAD(fsp,fsp->fd,data,n,pos);
 105
 106                 if (readret == -1) {
 107                         if ((errno == EAGAIN) && numretries) {
 108                                 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
 109                                 (void)sleep(10);
 110                                 --numretries;
 111                                 goto tryagain;
 112                         }
 113                         return -1;
 114                 }
 115 #else /* NO DMF fix. */
 116                 readret = SMB_VFS_PREAD(fsp,fsp->fd,data,n,pos);
 117
 118                 if (readret == -1)
 119                         return -1;
 120 #endif
 121                 if (readret > 0)
 122                         ret += readret;
 123         }
 124
 125         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
 126                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 127
 128         fsp->pos += ret;
 129         fsp->position_information = fsp->pos;
 130
 131         return(ret);
 132 }
 133
 134 /* how many write cache buffers have been allocated */
 135 static unsigned int allocated_write_caches;
 136
 137 /****************************************************************************
 138  *Really* write to a file.
 139 ****************************************************************************/
 140
 141 static ssize_t real_write_file(files_struct *fsp,char *data,SMB_OFF_T pos, size_t n)
 142 {
 143         ssize_t ret;
 144
 145         if (pos == -1)
 146                 ret = vfs_write_data(fsp, data, n);
 147         else {
 148                 fsp->pos = pos;
 149                 ret = vfs_pwrite_data(fsp, data, n, pos);
 150         }
 151
 152         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 153                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 154
 155         if (ret != -1) {
 156                 fsp->pos += ret;
 157
 158 /* Yes - this is correct - writes don't update this. JRA. */
 159 /* Found by Samba4 tests. */
 160 #if 0
 161                 fsp->position_information = fsp->pos;
 162 #endif
 163         }
 164
 165         return ret;
 166 }
 167
 168 /****************************************************************************
 169 write to a file
 170 ****************************************************************************/
 171
 172 ssize_t write_file(files_struct *fsp, char *data, SMB_OFF_T pos, size_t n)
 173 {
 174         write_cache *wcp = fsp->wcp;
 175         ssize_t total_written = 0;
 176         int write_path = -1;
 177
 178         if (fsp->print_file) {
 179                 int snum;
 180                 uint32 jobid;
 181
 182                 if (!rap_to_pjobid(fsp->rap_print_jobid, &snum, &jobid)) {
 183                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
 184                                                 (unsigned int)fsp->rap_print_jobid ));
 185                         errno = EBADF;
 186                         return -1;
 187                 }
 188
 189                 return print_job_write(SNUM(fsp->conn), jobid, data, n);
 190         }
 191
 192         if (!fsp->can_write) {
 193                 errno = EPERM;
 194                 return(0);
 195         }
 196
 197         if (!fsp->modified) {
 198                 SMB_STRUCT_STAT st;
 199                 fsp->modified = True;
 200
 201                 if (SMB_VFS_FSTAT(fsp,fsp->fd,&st) == 0) {
 202                         int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
 203                         fsp->size = (SMB_BIG_UINT)st.st_size;
 204                         if (MAP_ARCHIVE(fsp->conn) && !IS_DOS_ARCHIVE(dosmode))
 205                                 file_chmod(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st);
 206
 207                         /*
 208                          * If this is the first write and we have an exclusive oplock then setup
 209                          * the write cache.
 210                          */
 211
 212                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
 213                                 setup_write_cache(fsp, st.st_size);
 214                                 wcp = fsp->wcp;
 215                         }
 216                 }
 217         }
 218
 219 #ifdef WITH_PROFILE
 220         DO_PROFILE_INC(writecache_total_writes);
 221         if (!fsp->oplock_type) {
 222                 DO_PROFILE_INC(writecache_non_oplock_writes);
 223         }
 224 #endif
 225
 226         /*
 227          * If this file is level II oplocked then we need
 228          * to grab the shared memory lock and inform all
 229          * other files with a level II lock that they need
 230          * to flush their read caches. We keep the lock over
 231          * the shared memory area whilst doing this.
 232          */
 233
 234         release_level_2_oplocks_on_change(fsp);
 235
 236 #ifdef WITH_PROFILE
 237         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
 238                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
 239 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
 240                         profile_p->writecache_init_writes,
 241                         profile_p->writecache_abutted_writes,
 242                         profile_p->writecache_total_writes,
 243                         profile_p->writecache_non_oplock_writes,
 244                         profile_p->writecache_allocated_write_caches,
 245                         profile_p->writecache_num_write_caches,
 246                         profile_p->writecache_direct_writes,
 247                         profile_p->writecache_num_perfect_writes,
 248                         profile_p->writecache_read_hits ));
 249
 250                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
 251                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
 252                         profile_p->writecache_flushed_writes[READ_FLUSH],
 253                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
 254                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
 255                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
 256                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
 257                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
 258         }
 259 #endif
 260
 261         if(!wcp) {
 262                 DO_PROFILE_INC(writecache_direct_writes);
 263                 total_written = real_write_file(fsp, data, pos, n);
 264                 if ((total_written != -1) && (pos + total_written > (SMB_OFF_T)fsp->size))
 265                         fsp->size = (SMB_BIG_UINT)(pos + total_written);
 266                 return total_written;
 267         }
 268
 269         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
 270                 fsp->fsp_name, fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
 271
 272         fsp->pos = pos + n;
 273
 274         /*
 275          * If we have active cache and it isn't contiguous then we flush.
 276          * NOTE: There is a small problem with running out of disk ....
 277          */
 278
 279         if (wcp->data_size) {
 280
 281                 BOOL cache_flush_needed = False;
 282
 283                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 284
 285                         /* ASCII art.... JRA.
 286
 287       +--------------+-----
 288       | Cached data  | Rest of allocated cache buffer....
 289       +--------------+-----
 290
 291             +-------------------+
 292             | Data to write     |
 293             +-------------------+
 294
 295                         */
 296
 297                         /*
 298                          * Start of write overlaps or abutts the existing data.
 299                          */
 300
 301                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 302
 303                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 304
 305                         /*
 306                          * Update the current buffer size with the new data.
 307                          */
 308
 309                         if(pos + data_used > wcp->offset + wcp->data_size)
 310                                 wcp->data_size = pos + data_used - wcp->offset;
 311
 312                         /*
 313                          * Update the file size if changed.
 314                          */
 315
 316                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 317                                 wcp->file_size = wcp->offset + wcp->data_size;
 318                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 319                         }
 320
 321                         /*
 322                          * If we used all the data then
 323                          * return here.
 324                          */
 325
 326                         if(n == data_used)
 327                                 return n;
 328                         else
 329                                 cache_flush_needed = True;
 330
 331                         /*
 332                          * Move the start of data forward by the amount used,
 333                          * cut down the amount left by the same amount.
 334                          */
 335
 336                         data += data_used;
 337                         pos += data_used;
 338                         n -= data_used;
 339
 340                         DO_PROFILE_INC(writecache_abutted_writes);
 341                         total_written = data_used;
 342
 343                         write_path = 1;
 344
 345                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 346                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 347
 348                         /* ASCII art.... JRA.
 349
 350                         +---------------+
 351                         | Cache buffer  |
 352                         +---------------+
 353
 354             +-------------------+
 355             | Data to write     |
 356             +-------------------+
 357
 358                         */
 359
 360                         /*
 361                          * End of write overlaps the existing data.
 362                          */
 363
 364                         size_t data_used = pos + n - wcp->offset;
 365
 366                         memcpy(wcp->data, data + n - data_used, data_used);
 367
 368                         /*
 369                          * Update the current buffer size with the new data.
 370                          */
 371
 372                         if(pos + n > wcp->offset + wcp->data_size)
 373                                 wcp->data_size = pos + n - wcp->offset;
 374
 375                         /*
 376                          * Update the file size if changed.
 377                          */
 378
 379                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 380                                 wcp->file_size = wcp->offset + wcp->data_size;
 381                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 382                         }
 383
 384                         /*
 385                          * We don't need to move the start of data, but we
 386                          * cut down the amount left by the amount used.
 387                          */
 388
 389                         n -= data_used;
 390
 391                         /*
 392                          * We cannot have used all the data here.
 393                          */
 394
 395                         cache_flush_needed = True;
 396
 397                         DO_PROFILE_INC(writecache_abutted_writes);
 398                         total_written = data_used;
 399
 400                         write_path = 2;
 401
 402                 } else if ( (pos >= wcp->file_size) &&
 403                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 404                                         (pos > wcp->offset + wcp->data_size) &&
 405                                         (pos < wcp->offset + wcp->alloc_size) ) {
 406
 407                         /* ASCII art.... JRA.
 408
 409                        End of file ---->|
 410
 411                         +---------------+---------------+
 412                         | Cached data   | Cache buffer  |
 413                         +---------------+---------------+
 414
 415                                               +-------------------+
 416                                               | Data to write     |
 417                                               +-------------------+
 418
 419                         */
 420
 421                         /*
 422                          * Non-contiguous write part of which fits within
 423                          * the cache buffer and is extending the file
 424                          * and the cache contents reflect the current
 425                          * data up to the current end of the file.
 426                          */
 427
 428                         size_t data_used;
 429
 430                         if(pos + n <= wcp->offset + wcp->alloc_size)
 431                                 data_used = n;
 432                         else
 433                                 data_used = wcp->offset + wcp->alloc_size - pos;
 434
 435                         /*
 436                          * Fill in the non-continuous area with zeros.
 437                          */
 438
 439                         memset(wcp->data + wcp->data_size, '\0',
 440                                 pos - (wcp->offset + wcp->data_size) );
 441
 442                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 443
 444                         /*
 445                          * Update the current buffer size with the new data.
 446                          */
 447
 448                         if(pos + data_used > wcp->offset + wcp->data_size)
 449                                 wcp->data_size = pos + data_used - wcp->offset;
 450
 451                         /*
 452                          * Update the file size if changed.
 453                          */
 454
 455                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 456                                 wcp->file_size = wcp->offset + wcp->data_size;
 457                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 458                         }
 459
 460                         /*
 461                          * If we used all the data then
 462                          * return here.
 463                          */
 464
 465                         if(n == data_used)
 466                                 return n;
 467                         else
 468                                 cache_flush_needed = True;
 469
 470                         /*
 471                          * Move the start of data forward by the amount used,
 472                          * cut down the amount left by the same amount.
 473                          */
 474
 475                         data += data_used;
 476                         pos += data_used;
 477                         n -= data_used;
 478
 479                         DO_PROFILE_INC(writecache_abutted_writes);
 480                         total_written = data_used;
 481
 482                         write_path = 3;
 483
 484                 } else {
 485
 486                         /* ASCII art..... JRA.
 487
 488    Case 1).
 489
 490                         +---------------+---------------+
 491                         | Cached data   | Cache buffer  |
 492                         +---------------+---------------+
 493
 494                                                               +-------------------+
 495                                                               | Data to write     |
 496                                                               +-------------------+
 497
 498    Case 2).
 499
 500                            +---------------+---------------+
 501                            | Cached data   | Cache buffer  |
 502                            +---------------+---------------+
 503
 504    +-------------------+
 505    | Data to write     |
 506    +-------------------+
 507
 508     Case 3).
 509
 510                            +---------------+---------------+
 511                            | Cached data   | Cache buffer  |
 512                            +---------------+---------------+
 513
 514                   +-----------------------------------------------------+
 515                   | Data to write                                       |
 516                   +-----------------------------------------------------+
 517
 518                   */
 519
 520                         /*
 521                          * Write is bigger than buffer, or there is no overlap on the
 522                          * low or high ends.
 523                          */
 524
 525                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 526 len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 527
 528                         /*
 529                          * Update the file size if needed.
 530                          */
 531
 532                         if(pos + n > wcp->file_size) {
 533                                 wcp->file_size = pos + n;
 534                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 535                         }
 536
 537                         /*
 538                          * If write would fit in the cache, and is larger than
 539                          * the data already in the cache, flush the cache and
 540                          * preferentially copy the data new data into it. Otherwise
 541                          * just write the data directly.
 542                          */
 543
 544                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 545                                 cache_flush_needed = True;
 546                         } else {
 547                                 ssize_t ret = real_write_file(fsp, data, pos, n);
 548
 549                                 /*
 550                                  * If the write overlaps the entire cache, then
 551                                  * discard the current contents of the cache.
 552                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 553                                  */
 554
 555                                 if ((pos <= wcp->offset) &&
 556                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 557                                         DEBUG(9,("write_file: discarding overwritten write \
 558 cache: fd = %d, off=%.0f, size=%u\n", fsp->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 559                                         wcp->data_size = 0;
 560                                 }
 561
 562                                 DO_PROFILE_INC(writecache_direct_writes);
 563                                 if (ret == -1)
 564                                         return ret;
 565
 566                                 if (pos + ret > wcp->file_size) {
 567                                         wcp->file_size = pos + ret;
 568                                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 569                                 }
 570
 571                                 return ret;
 572                         }
 573
 574                         write_path = 4;
 575
 576                 }
 577
 578                 if(wcp->data_size > wcp->file_size) {
 579                         wcp->file_size = wcp->data_size;
 580                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 581                 }
 582
 583                 if (cache_flush_needed) {
 584                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 585 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 586                                 write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 587                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 588
 589                         flush_write_cache(fsp, WRITE_FLUSH);
 590                 }
 591         }
 592
 593         /*
 594          * If the write request is bigger than the cache
 595          * size, write it all out.
 596          */
 597
 598         if (n > wcp->alloc_size ) {
 599                 ssize_t ret = real_write_file(fsp, data, pos, n);
 600                 if (ret == -1)
 601                         return -1;
 602
 603                 if (pos + ret > wcp->file_size) {
 604                         wcp->file_size = pos + n;
 605                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 606                 }
 607
 608                 DO_PROFILE_INC(writecache_direct_writes);
 609                 return total_written + n;
 610         }
 611
 612         /*
 613          * If there's any data left, cache it.
 614          */
 615
 616         if (n) {
 617 #ifdef WITH_PROFILE
 618                 if (wcp->data_size) {
 619                         DO_PROFILE_INC(writecache_abutted_writes);
 620                 } else {
 621                         DO_PROFILE_INC(writecache_init_writes);
 622                 }
 623 #endif
 624                 memcpy(wcp->data+wcp->data_size, data, n);
 625                 if (wcp->data_size == 0) {
 626                         wcp->offset = pos;
 627                         DO_PROFILE_INC(writecache_num_write_caches);
 628                 }
 629                 wcp->data_size += n;
 630
 631                 /*
 632                  * Update the file size if changed.
 633                  */
 634
 635                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 636                         wcp->file_size = wcp->offset + wcp->data_size;
 637                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 638                 }
 639                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 640                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 641
 642                 total_written += n;
 643                 return total_written; /* .... that's a write :) */
 644         }
 645
 646         return total_written;
 647 }
 648
 649 /****************************************************************************
 650  Delete the write cache structure.
 651 ****************************************************************************/
 652
 653 void delete_write_cache(files_struct *fsp)
 654 {
 655         write_cache *wcp;
 656
 657         if(!fsp)
 658                 return;
 659
 660         if(!(wcp = fsp->wcp))
 661                 return;
 662
 663         DO_PROFILE_DEC(writecache_allocated_write_caches);
 664         allocated_write_caches--;
 665
 666         SMB_ASSERT(wcp->data_size == 0);
 667
 668         SAFE_FREE(wcp->data);
 669         SAFE_FREE(fsp->wcp);
 670
 671         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
 672 }
 673
 674 /****************************************************************************
 675  Setup the write cache structure.
 676 ****************************************************************************/
 677
 678 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 679 {
 680         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 681         write_cache *wcp;
 682
 683         if (allocated_write_caches >= MAX_WRITE_CACHES)
 684                 return False;
 685
 686         if(alloc_size == 0 || fsp->wcp)
 687                 return False;
 688
 689         if((wcp = (write_cache *)malloc(sizeof(write_cache))) == NULL) {
 690                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 691                 return False;
 692         }
 693
 694         wcp->file_size = file_size;
 695         wcp->offset = 0;
 696         wcp->alloc_size = alloc_size;
 697         wcp->data_size = 0;
 698         if((wcp->data = malloc(wcp->alloc_size)) == NULL) {
 699                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 700                         (unsigned int)wcp->alloc_size ));
 701                 SAFE_FREE(wcp);
 702                 return False;
 703         }
 704
 705         memset(wcp->data, '\0', wcp->alloc_size );
 706
 707         fsp->wcp = wcp;
 708         DO_PROFILE_INC(writecache_allocated_write_caches);
 709         allocated_write_caches++;
 710
 711         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 712                 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
 713
 714         return True;
 715 }
 716
 717 /****************************************************************************
 718  Cope with a size change.
 719 ****************************************************************************/
 720
 721 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 722 {
 723         fsp->size = (SMB_BIG_UINT)file_size;
 724         if(fsp->wcp) {
 725                 /* The cache *must* have been flushed before we do this. */
 726                 if (fsp->wcp->data_size != 0) {
 727                         pstring msg;
 728                         slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
 729 on file %s with write cache size = %lu\n", fsp->fsp_name, (unsigned long)fsp->wcp->data_size );
 730                         smb_panic(msg);
 731                 }
 732                 fsp->wcp->file_size = file_size;
 733         }
 734 }
 735
 736 /*******************************************************************
 737  Flush a write cache struct to disk.
 738 ********************************************************************/
 739
 740 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 741 {
 742         write_cache *wcp = fsp->wcp;
 743         size_t data_size;
 744         ssize_t ret;
 745
 746         if(!wcp || !wcp->data_size)
 747                 return 0;
 748
 749         data_size = wcp->data_size;
 750         wcp->data_size = 0;
 751
 752         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 753
 754         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 755                 fsp->fd, (double)wcp->offset, (unsigned int)data_size));
 756
 757 #ifdef WITH_PROFILE
 758         if(data_size == wcp->alloc_size)
 759                 DO_PROFILE_INC(writecache_num_perfect_writes);
 760 #endif
 761
 762         ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
 763
 764         /*
 765          * Ensure file size if kept up to date if write extends file.
 766          */
 767
 768         if ((ret != -1) && (wcp->offset + ret > wcp->file_size))
 769                 wcp->file_size = wcp->offset + ret;
 770
 771         return ret;
 772 }
 773
 774 /*******************************************************************
 775 sync a file
 776 ********************************************************************/
 777
 778 void sync_file(connection_struct *conn, files_struct *fsp)
 779 {
 780         if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
 781                 flush_write_cache(fsp, SYNC_FLUSH);
 782                 SMB_VFS_FSYNC(fsp,fsp->fd);
 783         }
 784 }
 785
 786
 787 /************************************************************
 788  Perform a stat whether a valid fd or not.
 789 ************************************************************/
 790
 791 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
 792 {
 793         if (fsp->fd == -1)
 794                 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
 795         else
 796                 return SMB_VFS_FSTAT(fsp,fsp->fd, pst);
 797 }