source3/smbd/fileio.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    read/write to a files_struct
   5    Copyright (C) Andrew Tridgell 1992-1998
   6    Copyright (C) Jeremy Allison 2000-2002. - write cache.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 static BOOL setup_write_cache(files_struct *, SMB_OFF_T);
  26
  27 /****************************************************************************
  28  Read from write cache if we can.
  29 ****************************************************************************/
  30
  31
  32 static BOOL read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  33 {
  34         write_cache *wcp = fsp->wcp;
  35
  36         if(!wcp)
  37                 return False;
  38
  39         if(n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size)
  40                 return False;
  41
  42         memcpy(data, wcp->data + (pos - wcp->offset), n);
  43
  44         DO_PROFILE_INC(writecache_read_hits);
  45
  46         return True;
  47 }
  48
  49 /****************************************************************************
  50  Read from a file.
  51 ****************************************************************************/
  52
  53 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  54 {
  55         ssize_t ret=0,readret;
  56
  57         /* you can't read from print files */
  58         if (fsp->print_file)
  59                 return -1;
  60
  61         /*
  62          * Serve from write cache if we can.
  63          */
  64
  65         if(read_from_write_cache(fsp, data, pos, n)) {
  66                 fsp->pos = pos + n;
  67                 fsp->position_information = fsp->pos;
  68                 return n;
  69         }
  70
  71         flush_write_cache(fsp, READ_FLUSH);
  72
  73         fsp->pos = pos;
  74
  75         if (n > 0) {
  76 #ifdef DMF_FIX
  77                 int numretries = 3;
  78 tryagain:
  79                 readret = SMB_VFS_PREAD(fsp,fsp->fd,data,n,pos);
  80
  81                 if (readret == -1) {
  82                         if ((errno == EAGAIN) && numretries) {
  83                                 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
  84                                 (void)sleep(10);
  85                                 --numretries;
  86                                 goto tryagain;
  87                         }
  88                         return -1;
  89                 }
  90 #else /* NO DMF fix. */
  91                 readret = SMB_VFS_PREAD(fsp,fsp->fd,data,n,pos);
  92
  93                 if (readret == -1)
  94                         return -1;
  95 #endif
  96                 if (readret > 0)
  97                         ret += readret;
  98         }
  99
 100         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
 101                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 102
 103         fsp->pos += ret;
 104         fsp->position_information = fsp->pos;
 105
 106         return(ret);
 107 }
 108
 109 /* how many write cache buffers have been allocated */
 110 static unsigned int allocated_write_caches;
 111
 112 /****************************************************************************
 113  *Really* write to a file.
 114 ****************************************************************************/
 115
 116 static ssize_t real_write_file(files_struct *fsp,char *data,SMB_OFF_T pos, size_t n)
 117 {
 118         ssize_t ret;
 119
 120         if (pos == -1)
 121                 ret = vfs_write_data(fsp, data, n);
 122         else {
 123                 fsp->pos = pos;
 124                 ret = vfs_pwrite_data(fsp, data, n, pos);
 125         }
 126
 127         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 128                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
 129
 130         if (ret != -1) {
 131                 fsp->pos += ret;
 132
 133 /* Yes - this is correct - writes don't update this. JRA. */
 134 /* Found by Samba4 tests. */
 135 #if 0
 136                 fsp->position_information = fsp->pos;
 137 #endif
 138         }
 139
 140         return ret;
 141 }
 142
 143 /****************************************************************************
 144 write to a file
 145 ****************************************************************************/
 146
 147 ssize_t write_file(files_struct *fsp, char *data, SMB_OFF_T pos, size_t n)
 148 {
 149         write_cache *wcp = fsp->wcp;
 150         ssize_t total_written = 0;
 151         int write_path = -1;
 152
 153         if (fsp->print_file) {
 154                 int snum;
 155                 uint32 jobid;
 156
 157                 if (!rap_to_pjobid(fsp->rap_print_jobid, &snum, &jobid)) {
 158                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
 159                                                 (unsigned int)fsp->rap_print_jobid ));
 160                         errno = EBADF;
 161                         return -1;
 162                 }
 163
 164                 return print_job_write(SNUM(fsp->conn), jobid, data, n);
 165         }
 166
 167         if (!fsp->can_write) {
 168                 errno = EPERM;
 169                 return(0);
 170         }
 171
 172         if (!fsp->modified) {
 173                 SMB_STRUCT_STAT st;
 174                 fsp->modified = True;
 175
 176                 if (SMB_VFS_FSTAT(fsp,fsp->fd,&st) == 0) {
 177                         int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
 178                         fsp->size = (SMB_BIG_UINT)st.st_size;
 179                         if (MAP_ARCHIVE(fsp->conn) && !IS_DOS_ARCHIVE(dosmode))
 180                                 file_chmod(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st);
 181
 182                         /*
 183                          * If this is the first write and we have an exclusive oplock then setup
 184                          * the write cache.
 185                          */
 186
 187                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
 188                                 setup_write_cache(fsp, st.st_size);
 189                                 wcp = fsp->wcp;
 190                         }
 191                 }
 192         }
 193
 194 #ifdef WITH_PROFILE
 195         DO_PROFILE_INC(writecache_total_writes);
 196         if (!fsp->oplock_type) {
 197                 DO_PROFILE_INC(writecache_non_oplock_writes);
 198         }
 199 #endif
 200
 201         /*
 202          * If this file is level II oplocked then we need
 203          * to grab the shared memory lock and inform all
 204          * other files with a level II lock that they need
 205          * to flush their read caches. We keep the lock over
 206          * the shared memory area whilst doing this.
 207          */
 208
 209         release_level_2_oplocks_on_change(fsp);
 210
 211 #ifdef WITH_PROFILE
 212         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
 213                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
 214 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
 215                         profile_p->writecache_init_writes,
 216                         profile_p->writecache_abutted_writes,
 217                         profile_p->writecache_total_writes,
 218                         profile_p->writecache_non_oplock_writes,
 219                         profile_p->writecache_allocated_write_caches,
 220                         profile_p->writecache_num_write_caches,
 221                         profile_p->writecache_direct_writes,
 222                         profile_p->writecache_num_perfect_writes,
 223                         profile_p->writecache_read_hits ));
 224
 225                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
 226                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
 227                         profile_p->writecache_flushed_writes[READ_FLUSH],
 228                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
 229                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
 230                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
 231                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
 232                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
 233         }
 234 #endif
 235
 236         if(!wcp) {
 237                 DO_PROFILE_INC(writecache_direct_writes);
 238                 total_written = real_write_file(fsp, data, pos, n);
 239                 if ((total_written != -1) && (pos + total_written > (SMB_OFF_T)fsp->size))
 240                         fsp->size = (SMB_BIG_UINT)(pos + total_written);
 241                 return total_written;
 242         }
 243
 244         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
 245                 fsp->fsp_name, fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
 246
 247         fsp->pos = pos + n;
 248
 249         /*
 250          * If we have active cache and it isn't contiguous then we flush.
 251          * NOTE: There is a small problem with running out of disk ....
 252          */
 253
 254         if (wcp->data_size) {
 255
 256                 BOOL cache_flush_needed = False;
 257
 258                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 259
 260                         /* ASCII art.... JRA.
 261
 262       +--------------+-----
 263       | Cached data  | Rest of allocated cache buffer....
 264       +--------------+-----
 265
 266             +-------------------+
 267             | Data to write     |
 268             +-------------------+
 269
 270                         */
 271
 272                         /*
 273                          * Start of write overlaps or abutts the existing data.
 274                          */
 275
 276                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 277
 278                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 279
 280                         /*
 281                          * Update the current buffer size with the new data.
 282                          */
 283
 284                         if(pos + data_used > wcp->offset + wcp->data_size)
 285                                 wcp->data_size = pos + data_used - wcp->offset;
 286
 287                         /*
 288                          * Update the file size if changed.
 289                          */
 290
 291                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 292                                 wcp->file_size = wcp->offset + wcp->data_size;
 293                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 294                         }
 295
 296                         /*
 297                          * If we used all the data then
 298                          * return here.
 299                          */
 300
 301                         if(n == data_used)
 302                                 return n;
 303                         else
 304                                 cache_flush_needed = True;
 305
 306                         /*
 307                          * Move the start of data forward by the amount used,
 308                          * cut down the amount left by the same amount.
 309                          */
 310
 311                         data += data_used;
 312                         pos += data_used;
 313                         n -= data_used;
 314
 315                         DO_PROFILE_INC(writecache_abutted_writes);
 316                         total_written = data_used;
 317
 318                         write_path = 1;
 319
 320                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 321                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 322
 323                         /* ASCII art.... JRA.
 324
 325                         +---------------+
 326                         | Cache buffer  |
 327                         +---------------+
 328
 329             +-------------------+
 330             | Data to write     |
 331             +-------------------+
 332
 333                         */
 334
 335                         /*
 336                          * End of write overlaps the existing data.
 337                          */
 338
 339                         size_t data_used = pos + n - wcp->offset;
 340
 341                         memcpy(wcp->data, data + n - data_used, data_used);
 342
 343                         /*
 344                          * Update the current buffer size with the new data.
 345                          */
 346
 347                         if(pos + n > wcp->offset + wcp->data_size)
 348                                 wcp->data_size = pos + n - wcp->offset;
 349
 350                         /*
 351                          * Update the file size if changed.
 352                          */
 353
 354                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 355                                 wcp->file_size = wcp->offset + wcp->data_size;
 356                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 357                         }
 358
 359                         /*
 360                          * We don't need to move the start of data, but we
 361                          * cut down the amount left by the amount used.
 362                          */
 363
 364                         n -= data_used;
 365
 366                         /*
 367                          * We cannot have used all the data here.
 368                          */
 369
 370                         cache_flush_needed = True;
 371
 372                         DO_PROFILE_INC(writecache_abutted_writes);
 373                         total_written = data_used;
 374
 375                         write_path = 2;
 376
 377                 } else if ( (pos >= wcp->file_size) &&
 378                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 379                                         (pos > wcp->offset + wcp->data_size) &&
 380                                         (pos < wcp->offset + wcp->alloc_size) ) {
 381
 382                         /* ASCII art.... JRA.
 383
 384                        End of file ---->|
 385
 386                         +---------------+---------------+
 387                         | Cached data   | Cache buffer  |
 388                         +---------------+---------------+
 389
 390                                               +-------------------+
 391                                               | Data to write     |
 392                                               +-------------------+
 393
 394                         */
 395
 396                         /*
 397                          * Non-contiguous write part of which fits within
 398                          * the cache buffer and is extending the file
 399                          * and the cache contents reflect the current
 400                          * data up to the current end of the file.
 401                          */
 402
 403                         size_t data_used;
 404
 405                         if(pos + n <= wcp->offset + wcp->alloc_size)
 406                                 data_used = n;
 407                         else
 408                                 data_used = wcp->offset + wcp->alloc_size - pos;
 409
 410                         /*
 411                          * Fill in the non-continuous area with zeros.
 412                          */
 413
 414                         memset(wcp->data + wcp->data_size, '\0',
 415                                 pos - (wcp->offset + wcp->data_size) );
 416
 417                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 418
 419                         /*
 420                          * Update the current buffer size with the new data.
 421                          */
 422
 423                         if(pos + data_used > wcp->offset + wcp->data_size)
 424                                 wcp->data_size = pos + data_used - wcp->offset;
 425
 426                         /*
 427                          * Update the file size if changed.
 428                          */
 429
 430                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 431                                 wcp->file_size = wcp->offset + wcp->data_size;
 432                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 433                         }
 434
 435                         /*
 436                          * If we used all the data then
 437                          * return here.
 438                          */
 439
 440                         if(n == data_used)
 441                                 return n;
 442                         else
 443                                 cache_flush_needed = True;
 444
 445                         /*
 446                          * Move the start of data forward by the amount used,
 447                          * cut down the amount left by the same amount.
 448                          */
 449
 450                         data += data_used;
 451                         pos += data_used;
 452                         n -= data_used;
 453
 454                         DO_PROFILE_INC(writecache_abutted_writes);
 455                         total_written = data_used;
 456
 457                         write_path = 3;
 458
 459                 } else {
 460
 461                         /* ASCII art..... JRA.
 462
 463    Case 1).
 464
 465                         +---------------+---------------+
 466                         | Cached data   | Cache buffer  |
 467                         +---------------+---------------+
 468
 469                                                               +-------------------+
 470                                                               | Data to write     |
 471                                                               +-------------------+
 472
 473    Case 2).
 474
 475                            +---------------+---------------+
 476                            | Cached data   | Cache buffer  |
 477                            +---------------+---------------+
 478
 479    +-------------------+
 480    | Data to write     |
 481    +-------------------+
 482
 483     Case 3).
 484
 485                            +---------------+---------------+
 486                            | Cached data   | Cache buffer  |
 487                            +---------------+---------------+
 488
 489                   +-----------------------------------------------------+
 490                   | Data to write                                       |
 491                   +-----------------------------------------------------+
 492
 493                   */
 494
 495                         /*
 496                          * Write is bigger than buffer, or there is no overlap on the
 497                          * low or high ends.
 498                          */
 499
 500                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 501 len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 502
 503                         /*
 504                          * Update the file size if needed.
 505                          */
 506
 507                         if(pos + n > wcp->file_size) {
 508                                 wcp->file_size = pos + n;
 509                                 fsp->size = (SMB_BIG_UINT)wcp->file_size;
 510                         }
 511
 512                         /*
 513                          * If write would fit in the cache, and is larger than
 514                          * the data already in the cache, flush the cache and
 515                          * preferentially copy the data new data into it. Otherwise
 516                          * just write the data directly.
 517                          */
 518
 519                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 520                                 cache_flush_needed = True;
 521                         } else {
 522                                 ssize_t ret = real_write_file(fsp, data, pos, n);
 523
 524                                 /*
 525                                  * If the write overlaps the entire cache, then
 526                                  * discard the current contents of the cache.
 527                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 528                                  */
 529
 530                                 if ((pos <= wcp->offset) &&
 531                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 532                                         DEBUG(9,("write_file: discarding overwritten write \
 533 cache: fd = %d, off=%.0f, size=%u\n", fsp->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 534                                         wcp->data_size = 0;
 535                                 }
 536
 537                                 DO_PROFILE_INC(writecache_direct_writes);
 538                                 if (ret == -1)
 539                                         return ret;
 540
 541                                 if (pos + ret > wcp->file_size) {
 542                                         wcp->file_size = pos + ret;
 543                                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 544                                 }
 545
 546                                 return ret;
 547                         }
 548
 549                         write_path = 4;
 550
 551                 }
 552
 553                 if(wcp->data_size > wcp->file_size) {
 554                         wcp->file_size = wcp->data_size;
 555                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 556                 }
 557
 558                 if (cache_flush_needed) {
 559                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 560 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 561                                 write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 562                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 563
 564                         flush_write_cache(fsp, WRITE_FLUSH);
 565                 }
 566         }
 567
 568         /*
 569          * If the write request is bigger than the cache
 570          * size, write it all out.
 571          */
 572
 573         if (n > wcp->alloc_size ) {
 574                 ssize_t ret = real_write_file(fsp, data, pos, n);
 575                 if (ret == -1)
 576                         return -1;
 577
 578                 if (pos + ret > wcp->file_size) {
 579                         wcp->file_size = pos + n;
 580                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 581                 }
 582
 583                 DO_PROFILE_INC(writecache_direct_writes);
 584                 return total_written + n;
 585         }
 586
 587         /*
 588          * If there's any data left, cache it.
 589          */
 590
 591         if (n) {
 592 #ifdef WITH_PROFILE
 593                 if (wcp->data_size) {
 594                         DO_PROFILE_INC(writecache_abutted_writes);
 595                 } else {
 596                         DO_PROFILE_INC(writecache_init_writes);
 597                 }
 598 #endif
 599                 memcpy(wcp->data+wcp->data_size, data, n);
 600                 if (wcp->data_size == 0) {
 601                         wcp->offset = pos;
 602                         DO_PROFILE_INC(writecache_num_write_caches);
 603                 }
 604                 wcp->data_size += n;
 605
 606                 /*
 607                  * Update the file size if changed.
 608                  */
 609
 610                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 611                         wcp->file_size = wcp->offset + wcp->data_size;
 612                         fsp->size = (SMB_BIG_UINT)wcp->file_size;
 613                 }
 614                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 615                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 616
 617                 total_written += n;
 618                 return total_written; /* .... that's a write :) */
 619         }
 620
 621         return total_written;
 622 }
 623
 624 /****************************************************************************
 625  Delete the write cache structure.
 626 ****************************************************************************/
 627
 628 void delete_write_cache(files_struct *fsp)
 629 {
 630         write_cache *wcp;
 631
 632         if(!fsp)
 633                 return;
 634
 635         if(!(wcp = fsp->wcp))
 636                 return;
 637
 638         DO_PROFILE_DEC(writecache_allocated_write_caches);
 639         allocated_write_caches--;
 640
 641         SMB_ASSERT(wcp->data_size == 0);
 642
 643         SAFE_FREE(wcp->data);
 644         SAFE_FREE(fsp->wcp);
 645
 646         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
 647 }
 648
 649 /****************************************************************************
 650  Setup the write cache structure.
 651 ****************************************************************************/
 652
 653 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 654 {
 655         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 656         write_cache *wcp;
 657
 658         if (allocated_write_caches >= MAX_WRITE_CACHES)
 659                 return False;
 660
 661         if(alloc_size == 0 || fsp->wcp)
 662                 return False;
 663
 664         if((wcp = (write_cache *)malloc(sizeof(write_cache))) == NULL) {
 665                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 666                 return False;
 667         }
 668
 669         wcp->file_size = file_size;
 670         wcp->offset = 0;
 671         wcp->alloc_size = alloc_size;
 672         wcp->data_size = 0;
 673         if((wcp->data = malloc(wcp->alloc_size)) == NULL) {
 674                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 675                         (unsigned int)wcp->alloc_size ));
 676                 SAFE_FREE(wcp);
 677                 return False;
 678         }
 679
 680         memset(wcp->data, '\0', wcp->alloc_size );
 681
 682         fsp->wcp = wcp;
 683         DO_PROFILE_INC(writecache_allocated_write_caches);
 684         allocated_write_caches++;
 685
 686         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 687                 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
 688
 689         return True;
 690 }
 691
 692 /****************************************************************************
 693  Cope with a size change.
 694 ****************************************************************************/
 695
 696 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 697 {
 698         fsp->size = (SMB_BIG_UINT)file_size;
 699         if(fsp->wcp) {
 700                 /* The cache *must* have been flushed before we do this. */
 701                 if (fsp->wcp->data_size != 0) {
 702                         pstring msg;
 703                         slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
 704 on file %s with write cache size = %lu\n", fsp->fsp_name, (unsigned long)fsp->wcp->data_size );
 705                         smb_panic(msg);
 706                 }
 707                 fsp->wcp->file_size = file_size;
 708         }
 709 }
 710
 711 /*******************************************************************
 712  Flush a write cache struct to disk.
 713 ********************************************************************/
 714
 715 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 716 {
 717         write_cache *wcp = fsp->wcp;
 718         size_t data_size;
 719         ssize_t ret;
 720
 721         if(!wcp || !wcp->data_size)
 722                 return 0;
 723
 724         data_size = wcp->data_size;
 725         wcp->data_size = 0;
 726
 727         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 728
 729         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 730                 fsp->fd, (double)wcp->offset, (unsigned int)data_size));
 731
 732 #ifdef WITH_PROFILE
 733         if(data_size == wcp->alloc_size)
 734                 DO_PROFILE_INC(writecache_num_perfect_writes);
 735 #endif
 736
 737         ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
 738
 739         /*
 740          * Ensure file size if kept up to date if write extends file.
 741          */
 742
 743         if ((ret != -1) && (wcp->offset + ret > wcp->file_size))
 744                 wcp->file_size = wcp->offset + ret;
 745
 746         return ret;
 747 }
 748
 749 /*******************************************************************
 750 sync a file
 751 ********************************************************************/
 752
 753 void sync_file(connection_struct *conn, files_struct *fsp)
 754 {
 755         if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
 756                 flush_write_cache(fsp, SYNC_FLUSH);
 757                 SMB_VFS_FSYNC(fsp,fsp->fd);
 758         }
 759 }
 760
 761
 762 /************************************************************
 763  Perform a stat whether a valid fd or not.
 764 ************************************************************/
 765
 766 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
 767 {
 768         if (fsp->fd == -1)
 769                 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
 770         else
 771                 return SMB_VFS_FSTAT(fsp,fsp->fd, pst);
 772 }