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 3 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, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smbd/globals.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 static bool read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  32 {
  33         write_cache *wcp = fsp->wcp;
  34
  35         if(!wcp) {
  36                 return False;
  37         }
  38
  39         if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) {
  40                 return False;
  41         }
  42
  43         memcpy(data, wcp->data + (pos - wcp->offset), n);
  44
  45         DO_PROFILE_INC(writecache_read_hits);
  46
  47         return True;
  48 }
  49
  50 /****************************************************************************
  51  Read from a file.
  52 ****************************************************************************/
  53
  54 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
  55 {
  56         ssize_t ret=0,readret;
  57
  58         /* you can't read from print files */
  59         if (fsp->print_file) {
  60                 errno = EBADF;
  61                 return -1;
  62         }
  63
  64         /*
  65          * Serve from write cache if we can.
  66          */
  67
  68         if(read_from_write_cache(fsp, data, pos, n)) {
  69                 fsp->fh->pos = pos + n;
  70                 fsp->fh->position_information = fsp->fh->pos;
  71                 return n;
  72         }
  73
  74         flush_write_cache(fsp, READ_FLUSH);
  75
  76         fsp->fh->pos = pos;
  77
  78         if (n > 0) {
  79 #ifdef DMF_FIX
  80                 int numretries = 3;
  81 tryagain:
  82                 readret = SMB_VFS_PREAD(fsp,data,n,pos);
  83
  84                 if (readret == -1) {
  85                         if ((errno == EAGAIN) && numretries) {
  86                                 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
  87                                 (void)sleep(10);
  88                                 --numretries;
  89                                 goto tryagain;
  90                         }
  91                         return -1;
  92                 }
  93 #else /* NO DMF fix. */
  94                 readret = SMB_VFS_PREAD(fsp,data,n,pos);
  95
  96                 if (readret == -1) {
  97                         return -1;
  98                 }
  99 #endif
 100                 if (readret > 0) {
 101                         ret += readret;
 102                 }
 103         }
 104
 105         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
 106                   fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
 107
 108         fsp->fh->pos += ret;
 109         fsp->fh->position_information = fsp->fh->pos;
 110
 111         return(ret);
 112 }
 113
 114 /****************************************************************************
 115  *Really* write to a file.
 116 ****************************************************************************/
 117
 118 static ssize_t real_write_file(struct smb_request *req,
 119                                 files_struct *fsp,
 120                                 const char *data,
 121                                 SMB_OFF_T pos,
 122                                 size_t n)
 123 {
 124         ssize_t ret;
 125
 126         if (pos == -1) {
 127                 ret = vfs_write_data(req, fsp, data, n);
 128         } else {
 129                 fsp->fh->pos = pos;
 130                 if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
 131                         if (vfs_fill_sparse(fsp, pos) == -1) {
 132                                 return -1;
 133                         }
 134                 }
 135                 ret = vfs_pwrite_data(req, fsp, data, n, pos);
 136         }
 137
 138         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 139                   fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
 140
 141         if (ret != -1) {
 142                 fsp->fh->pos += ret;
 143
 144 /* Yes - this is correct - writes don't update this. JRA. */
 145 /* Found by Samba4 tests. */
 146 #if 0
 147                 fsp->position_information = fsp->pos;
 148 #endif
 149         }
 150
 151         return ret;
 152 }
 153
 154 /****************************************************************************
 155  File size cache change.
 156  Updates size on disk but doesn't flush the cache.
 157 ****************************************************************************/
 158
 159 static int wcp_file_size_change(files_struct *fsp)
 160 {
 161         int ret;
 162         write_cache *wcp = fsp->wcp;
 163
 164         wcp->file_size = wcp->offset + wcp->data_size;
 165         ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
 166         if (ret == -1) {
 167                 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f "
 168                          "error %s\n", fsp_str_dbg(fsp),
 169                          (double)wcp->file_size, strerror(errno)));
 170         }
 171         return ret;
 172 }
 173
 174 void update_write_time_handler(struct event_context *ctx,
 175                                       struct timed_event *te,
 176                                       struct timeval now,
 177                                       void *private_data)
 178 {
 179         files_struct *fsp = (files_struct *)private_data;
 180
 181         DEBUG(5, ("Update write time on %s\n", fsp_str_dbg(fsp)));
 182
 183         /* change the write time in the open file db. */
 184         (void)set_write_time(fsp->file_id, timespec_current());
 185
 186         /* And notify. */
 187         notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
 188                      FILE_NOTIFY_CHANGE_LAST_WRITE, fsp->fsp_name->base_name);
 189
 190         /* Remove the timed event handler. */
 191         TALLOC_FREE(fsp->update_write_time_event);
 192 }
 193
 194 /*********************************************************
 195  Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
 196  in the future.
 197 *********************************************************/
 198
 199 void trigger_write_time_update(struct files_struct *fsp)
 200 {
 201         int delay;
 202
 203         if (fsp->posix_open) {
 204                 /* Don't use delayed writes on POSIX files. */
 205                 return;
 206         }
 207
 208         if (fsp->write_time_forced) {
 209                 /* No point - "sticky" write times
 210                  * in effect.
 211                  */
 212                 return;
 213         }
 214
 215         /* We need to remember someone did a write
 216          * and update to current time on close. */
 217
 218         fsp->update_write_time_on_close = true;
 219
 220         if (fsp->update_write_time_triggered) {
 221                 /*
 222                  * We only update the write time after 2 seconds
 223                  * on the first normal write. After that
 224                  * no other writes affect this until close.
 225                  */
 226                 return;
 227         }
 228         fsp->update_write_time_triggered = true;
 229
 230         delay = lp_parm_int(SNUM(fsp->conn),
 231                             "smbd", "writetimeupdatedelay",
 232                             WRITE_TIME_UPDATE_USEC_DELAY);
 233
 234         DEBUG(5, ("Update write time %d usec later on %s\n",
 235                   delay, fsp_str_dbg(fsp)));
 236
 237         /* trigger the update 2 seconds later */
 238         fsp->update_write_time_event =
 239                 event_add_timed(smbd_event_context(), NULL,
 240                                 timeval_current_ofs(0, delay),
 241                                 update_write_time_handler, fsp);
 242 }
 243
 244 void trigger_write_time_update_immediate(struct files_struct *fsp)
 245 {
 246         struct smb_file_time ft;
 247
 248         if (fsp->posix_open) {
 249                 /* Don't use delayed writes on POSIX files. */
 250                 return;
 251         }
 252
 253         if (fsp->write_time_forced) {
 254                 /*
 255                  * No point - "sticky" write times
 256                  * in effect.
 257                  */
 258                 return;
 259         }
 260
 261         TALLOC_FREE(fsp->update_write_time_event);
 262         DEBUG(5, ("Update write time immediate on %s\n",
 263                   fsp_str_dbg(fsp)));
 264
 265         /* After an immediate update, reset the trigger. */
 266         fsp->update_write_time_triggered = true;
 267         fsp->update_write_time_on_close = false;
 268
 269         ZERO_STRUCT(ft);
 270         ft.mtime = timespec_current();
 271
 272         /* Update the time in the open file db. */
 273         (void)set_write_time(fsp->file_id, ft.mtime);
 274
 275         /* Now set on disk - takes care of notify. */
 276         (void)smb_set_file_time(fsp->conn, fsp, fsp->fsp_name, &ft, false);
 277 }
 278
 279 /****************************************************************************
 280  Write to a file.
 281 ****************************************************************************/
 282
 283 ssize_t write_file(struct smb_request *req,
 284                         files_struct *fsp,
 285                         const char *data,
 286                         SMB_OFF_T pos,
 287                         size_t n)
 288 {
 289         write_cache *wcp = fsp->wcp;
 290         ssize_t total_written = 0;
 291         int write_path = -1;
 292
 293         if (fsp->print_file) {
 294                 uint32 jobid;
 295
 296                 if (!rap_to_pjobid(fsp->rap_print_jobid, NULL, &jobid)) {
 297                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
 298                                                 (unsigned int)fsp->rap_print_jobid ));
 299                         errno = EBADF;
 300                         return -1;
 301                 }
 302
 303                 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
 304         }
 305
 306         if (!fsp->can_write) {
 307                 errno = EPERM;
 308                 return -1;
 309         }
 310
 311         if (!fsp->modified) {
 312                 fsp->modified = True;
 313
 314                 if (SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st) == 0) {
 315                         trigger_write_time_update(fsp);
 316                         if (!fsp->posix_open &&
 317                                         (lp_store_dos_attributes(SNUM(fsp->conn)) ||
 318                                         MAP_ARCHIVE(fsp->conn))) {
 319                                 int dosmode = dos_mode(fsp->conn, fsp->fsp_name);
 320                                 if (!IS_DOS_ARCHIVE(dosmode)) {
 321                                         file_set_dosmode(fsp->conn, fsp->fsp_name,
 322                                                  dosmode | aARCH, NULL, false);
 323                                 }
 324                         }
 325
 326                         /*
 327                          * If this is the first write and we have an exclusive oplock then setup
 328                          * the write cache.
 329                          */
 330
 331                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
 332                                 setup_write_cache(fsp,
 333                                                  fsp->fsp_name->st.st_ex_size);
 334                                 wcp = fsp->wcp;
 335                         }
 336                 }
 337         }
 338
 339 #ifdef WITH_PROFILE
 340         DO_PROFILE_INC(writecache_total_writes);
 341         if (!fsp->oplock_type) {
 342                 DO_PROFILE_INC(writecache_non_oplock_writes);
 343         }
 344 #endif
 345
 346         /*
 347          * If this file is level II oplocked then we need
 348          * to grab the shared memory lock and inform all
 349          * other files with a level II lock that they need
 350          * to flush their read caches. We keep the lock over
 351          * the shared memory area whilst doing this.
 352          */
 353
 354         /* This should actually be improved to span the write. */
 355         contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
 356         contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
 357
 358 #ifdef WITH_PROFILE
 359         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
 360                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
 361 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
 362                         profile_p->writecache_init_writes,
 363                         profile_p->writecache_abutted_writes,
 364                         profile_p->writecache_total_writes,
 365                         profile_p->writecache_non_oplock_writes,
 366                         profile_p->writecache_allocated_write_caches,
 367                         profile_p->writecache_num_write_caches,
 368                         profile_p->writecache_direct_writes,
 369                         profile_p->writecache_num_perfect_writes,
 370                         profile_p->writecache_read_hits ));
 371
 372                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
 373                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
 374                         profile_p->writecache_flushed_writes[READ_FLUSH],
 375                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
 376                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
 377                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
 378                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
 379                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
 380         }
 381 #endif
 382
 383         if (wcp && req->unread_bytes) {
 384                 /* If we're using receivefile don't
 385                  * deal with a write cache.
 386                  */
 387                 flush_write_cache(fsp, WRITE_FLUSH);
 388                 delete_write_cache(fsp);
 389                 wcp = NULL;
 390         }
 391
 392         if(!wcp) {
 393                 DO_PROFILE_INC(writecache_direct_writes);
 394                 total_written = real_write_file(req, fsp, data, pos, n);
 395                 return total_written;
 396         }
 397
 398         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f "
 399                  "wcp->data_size=%u\n", fsp_str_dbg(fsp), fsp->fh->fd,
 400                  (double)pos, (unsigned int)n, (double)wcp->offset,
 401                  (unsigned int)wcp->data_size));
 402
 403         fsp->fh->pos = pos + n;
 404
 405         /*
 406          * If we have active cache and it isn't contiguous then we flush.
 407          * NOTE: There is a small problem with running out of disk ....
 408          */
 409
 410         if (wcp->data_size) {
 411                 bool cache_flush_needed = False;
 412
 413                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 414
 415                         /* ASCII art.... JRA.
 416
 417       +--------------+-----
 418       | Cached data  | Rest of allocated cache buffer....
 419       +--------------+-----
 420
 421             +-------------------+
 422             | Data to write     |
 423             +-------------------+
 424
 425                         */
 426
 427                         /*
 428                          * Start of write overlaps or abutts the existing data.
 429                          */
 430
 431                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 432
 433                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 434
 435                         /*
 436                          * Update the current buffer size with the new data.
 437                          */
 438
 439                         if(pos + data_used > wcp->offset + wcp->data_size) {
 440                                 wcp->data_size = pos + data_used - wcp->offset;
 441                         }
 442
 443                         /*
 444                          * Update the file size if changed.
 445                          */
 446
 447                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 448                                 if (wcp_file_size_change(fsp) == -1) {
 449                                         return -1;
 450                                 }
 451                         }
 452
 453                         /*
 454                          * If we used all the data then
 455                          * return here.
 456                          */
 457
 458                         if(n == data_used) {
 459                                 return n;
 460                         } else {
 461                                 cache_flush_needed = True;
 462                         }
 463                         /*
 464                          * Move the start of data forward by the amount used,
 465                          * cut down the amount left by the same amount.
 466                          */
 467
 468                         data += data_used;
 469                         pos += data_used;
 470                         n -= data_used;
 471
 472                         DO_PROFILE_INC(writecache_abutted_writes);
 473                         total_written = data_used;
 474
 475                         write_path = 1;
 476
 477                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 478                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 479
 480                         /* ASCII art.... JRA.
 481
 482                         +---------------+
 483                         | Cache buffer  |
 484                         +---------------+
 485
 486             +-------------------+
 487             | Data to write     |
 488             +-------------------+
 489
 490                         */
 491
 492                         /*
 493                          * End of write overlaps the existing data.
 494                          */
 495
 496                         size_t data_used = pos + n - wcp->offset;
 497
 498                         memcpy(wcp->data, data + n - data_used, data_used);
 499
 500                         /*
 501                          * Update the current buffer size with the new data.
 502                          */
 503
 504                         if(pos + n > wcp->offset + wcp->data_size) {
 505                                 wcp->data_size = pos + n - wcp->offset;
 506                         }
 507
 508                         /*
 509                          * Update the file size if changed.
 510                          */
 511
 512                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 513                                 if (wcp_file_size_change(fsp) == -1) {
 514                                         return -1;
 515                                 }
 516                         }
 517
 518                         /*
 519                          * We don't need to move the start of data, but we
 520                          * cut down the amount left by the amount used.
 521                          */
 522
 523                         n -= data_used;
 524
 525                         /*
 526                          * We cannot have used all the data here.
 527                          */
 528
 529                         cache_flush_needed = True;
 530
 531                         DO_PROFILE_INC(writecache_abutted_writes);
 532                         total_written = data_used;
 533
 534                         write_path = 2;
 535
 536                 } else if ( (pos >= wcp->file_size) &&
 537                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 538                                         (pos > wcp->offset + wcp->data_size) &&
 539                                         (pos < wcp->offset + wcp->alloc_size) ) {
 540
 541                         /* ASCII art.... JRA.
 542
 543                        End of file ---->|
 544
 545                         +---------------+---------------+
 546                         | Cached data   | Cache buffer  |
 547                         +---------------+---------------+
 548
 549                                               +-------------------+
 550                                               | Data to write     |
 551                                               +-------------------+
 552
 553                         */
 554
 555                         /*
 556                          * Non-contiguous write part of which fits within
 557                          * the cache buffer and is extending the file
 558                          * and the cache contents reflect the current
 559                          * data up to the current end of the file.
 560                          */
 561
 562                         size_t data_used;
 563
 564                         if(pos + n <= wcp->offset + wcp->alloc_size) {
 565                                 data_used = n;
 566                         } else {
 567                                 data_used = wcp->offset + wcp->alloc_size - pos;
 568                         }
 569
 570                         /*
 571                          * Fill in the non-continuous area with zeros.
 572                          */
 573
 574                         memset(wcp->data + wcp->data_size, '\0',
 575                                 pos - (wcp->offset + wcp->data_size) );
 576
 577                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 578
 579                         /*
 580                          * Update the current buffer size with the new data.
 581                          */
 582
 583                         if(pos + data_used > wcp->offset + wcp->data_size) {
 584                                 wcp->data_size = pos + data_used - wcp->offset;
 585                         }
 586
 587                         /*
 588                          * Update the file size if changed.
 589                          */
 590
 591                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 592                                 if (wcp_file_size_change(fsp) == -1) {
 593                                         return -1;
 594                                 }
 595                         }
 596
 597                         /*
 598                          * If we used all the data then
 599                          * return here.
 600                          */
 601
 602                         if(n == data_used) {
 603                                 return n;
 604                         } else {
 605                                 cache_flush_needed = True;
 606                         }
 607
 608                         /*
 609                          * Move the start of data forward by the amount used,
 610                          * cut down the amount left by the same amount.
 611                          */
 612
 613                         data += data_used;
 614                         pos += data_used;
 615                         n -= data_used;
 616
 617                         DO_PROFILE_INC(writecache_abutted_writes);
 618                         total_written = data_used;
 619
 620                         write_path = 3;
 621
 622                 } else if ( (pos >= wcp->file_size) &&
 623                             (n == 1) &&
 624                             (wcp->file_size == wcp->offset + wcp->data_size) &&
 625                             (pos < wcp->file_size + wcp->alloc_size)) {
 626
 627                         /*
 628
 629                 End of file ---->|
 630
 631                  +---------------+---------------+
 632                  | Cached data   | Cache buffer  |
 633                  +---------------+---------------+
 634
 635                                  |<------- allocated size ---------------->|
 636
 637                                                          +--------+
 638                                                          | 1 Byte |
 639                                                          +--------+
 640
 641                         MS-Office seems to do this a lot to determine if there's enough
 642                         space on the filesystem to write a new file.
 643
 644                         Change to :
 645
 646                 End of file ---->|
 647                                  +-----------------------+--------+
 648                                  | Zeroed Cached data    | 1 Byte |
 649                                  +-----------------------+--------+
 650                         */
 651
 652                         flush_write_cache(fsp, WRITE_FLUSH);
 653                         wcp->offset = wcp->file_size;
 654                         wcp->data_size = pos - wcp->file_size + 1;
 655                         memset(wcp->data, '\0', wcp->data_size);
 656                         memcpy(wcp->data + wcp->data_size-1, data, 1);
 657
 658                         /*
 659                          * Update the file size if changed.
 660                          */
 661
 662                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 663                                 if (wcp_file_size_change(fsp) == -1) {
 664                                         return -1;
 665                                 }
 666                         }
 667
 668                         return n;
 669
 670                 } else {
 671
 672                         /* ASCII art..... JRA.
 673
 674    Case 1).
 675
 676                         +---------------+---------------+
 677                         | Cached data   | Cache buffer  |
 678                         +---------------+---------------+
 679
 680                                                               +-------------------+
 681                                                               | Data to write     |
 682                                                               +-------------------+
 683
 684    Case 2).
 685
 686                            +---------------+---------------+
 687                            | Cached data   | Cache buffer  |
 688                            +---------------+---------------+
 689
 690    +-------------------+
 691    | Data to write     |
 692    +-------------------+
 693
 694     Case 3).
 695
 696                            +---------------+---------------+
 697                            | Cached data   | Cache buffer  |
 698                            +---------------+---------------+
 699
 700                   +-----------------------------------------------------+
 701                   | Data to write                                       |
 702                   +-----------------------------------------------------+
 703
 704                   */
 705
 706                         /*
 707                          * Write is bigger than buffer, or there is no overlap on the
 708                          * low or high ends.
 709                          */
 710
 711                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 712 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 713
 714                         /*
 715                          * If write would fit in the cache, and is larger than
 716                          * the data already in the cache, flush the cache and
 717                          * preferentially copy the data new data into it. Otherwise
 718                          * just write the data directly.
 719                          */
 720
 721                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 722                                 cache_flush_needed = True;
 723                         } else {
 724                                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
 725
 726                                 /*
 727                                  * If the write overlaps the entire cache, then
 728                                  * discard the current contents of the cache.
 729                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 730                                  */
 731
 732                                 if ((pos <= wcp->offset) &&
 733                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 734                                         DEBUG(9,("write_file: discarding overwritten write \
 735 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 736                                         wcp->data_size = 0;
 737                                 }
 738
 739                                 DO_PROFILE_INC(writecache_direct_writes);
 740                                 if (ret == -1) {
 741                                         return ret;
 742                                 }
 743
 744                                 if (pos + ret > wcp->file_size) {
 745                                         wcp->file_size = pos + ret;
 746                                 }
 747
 748                                 return ret;
 749                         }
 750
 751                         write_path = 4;
 752
 753                 }
 754
 755                 if (cache_flush_needed) {
 756                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 757 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 758                                 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 759                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 760
 761                         flush_write_cache(fsp, WRITE_FLUSH);
 762                 }
 763         }
 764
 765         /*
 766          * If the write request is bigger than the cache
 767          * size, write it all out.
 768          */
 769
 770         if (n > wcp->alloc_size ) {
 771                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
 772                 if (ret == -1) {
 773                         return -1;
 774                 }
 775
 776                 if (pos + ret > wcp->file_size) {
 777                         wcp->file_size = pos + n;
 778                 }
 779
 780                 DO_PROFILE_INC(writecache_direct_writes);
 781                 return total_written + n;
 782         }
 783
 784         /*
 785          * If there's any data left, cache it.
 786          */
 787
 788         if (n) {
 789 #ifdef WITH_PROFILE
 790                 if (wcp->data_size) {
 791                         DO_PROFILE_INC(writecache_abutted_writes);
 792                 } else {
 793                         DO_PROFILE_INC(writecache_init_writes);
 794                 }
 795 #endif
 796                 memcpy(wcp->data+wcp->data_size, data, n);
 797                 if (wcp->data_size == 0) {
 798                         wcp->offset = pos;
 799                         DO_PROFILE_INC(writecache_num_write_caches);
 800                 }
 801                 wcp->data_size += n;
 802
 803                 /*
 804                  * Update the file size if changed.
 805                  */
 806
 807                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 808                         if (wcp_file_size_change(fsp) == -1) {
 809                                 return -1;
 810                         }
 811                 }
 812                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 813                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 814
 815                 total_written += n;
 816                 return total_written; /* .... that's a write :) */
 817         }
 818
 819         return total_written;
 820 }
 821
 822 /****************************************************************************
 823  Delete the write cache structure.
 824 ****************************************************************************/
 825
 826 void delete_write_cache(files_struct *fsp)
 827 {
 828         write_cache *wcp;
 829
 830         if(!fsp) {
 831                 return;
 832         }
 833
 834         if(!(wcp = fsp->wcp)) {
 835                 return;
 836         }
 837
 838         DO_PROFILE_DEC(writecache_allocated_write_caches);
 839         allocated_write_caches--;
 840
 841         SMB_ASSERT(wcp->data_size == 0);
 842
 843         SAFE_FREE(wcp->data);
 844         SAFE_FREE(fsp->wcp);
 845
 846         DEBUG(10,("delete_write_cache: File %s deleted write cache\n",
 847                   fsp_str_dbg(fsp)));
 848 }
 849
 850 /****************************************************************************
 851  Setup the write cache structure.
 852 ****************************************************************************/
 853
 854 static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 855 {
 856         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 857         write_cache *wcp;
 858
 859         if (allocated_write_caches >= MAX_WRITE_CACHES) {
 860                 return False;
 861         }
 862
 863         if(alloc_size == 0 || fsp->wcp) {
 864                 return False;
 865         }
 866
 867         if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
 868                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 869                 return False;
 870         }
 871
 872         wcp->file_size = file_size;
 873         wcp->offset = 0;
 874         wcp->alloc_size = alloc_size;
 875         wcp->data_size = 0;
 876         if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
 877                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 878                         (unsigned int)wcp->alloc_size ));
 879                 SAFE_FREE(wcp);
 880                 return False;
 881         }
 882
 883         memset(wcp->data, '\0', wcp->alloc_size );
 884
 885         fsp->wcp = wcp;
 886         DO_PROFILE_INC(writecache_allocated_write_caches);
 887         allocated_write_caches++;
 888
 889         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 890                   fsp_str_dbg(fsp), (unsigned long)wcp->alloc_size));
 891
 892         return True;
 893 }
 894
 895 /****************************************************************************
 896  Cope with a size change.
 897 ****************************************************************************/
 898
 899 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 900 {
 901         if(fsp->wcp) {
 902                 /* The cache *must* have been flushed before we do this. */
 903                 if (fsp->wcp->data_size != 0) {
 904                         char *msg;
 905                         if (asprintf(&msg, "set_filelen_write_cache: size change "
 906                                  "on file %s with write cache size = %lu\n",
 907                                  fsp->fsp_name->base_name,
 908                                  (unsigned long)fsp->wcp->data_size) != -1) {
 909                                 smb_panic(msg);
 910                         } else {
 911                                 smb_panic("set_filelen_write_cache");
 912                         }
 913                 }
 914                 fsp->wcp->file_size = file_size;
 915         }
 916 }
 917
 918 /*******************************************************************
 919  Flush a write cache struct to disk.
 920 ********************************************************************/
 921
 922 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 923 {
 924         write_cache *wcp = fsp->wcp;
 925         size_t data_size;
 926         ssize_t ret;
 927
 928         if(!wcp || !wcp->data_size) {
 929                 return 0;
 930         }
 931
 932         data_size = wcp->data_size;
 933         wcp->data_size = 0;
 934
 935         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 936
 937         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 938                 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
 939
 940 #ifdef WITH_PROFILE
 941         if(data_size == wcp->alloc_size) {
 942                 DO_PROFILE_INC(writecache_num_perfect_writes);
 943         }
 944 #endif
 945
 946         ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
 947
 948         /*
 949          * Ensure file size if kept up to date if write extends file.
 950          */
 951
 952         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
 953                 wcp->file_size = wcp->offset + ret;
 954         }
 955
 956         return ret;
 957 }
 958
 959 /*******************************************************************
 960 sync a file
 961 ********************************************************************/
 962
 963 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
 964 {
 965         if (fsp->fh->fd == -1)
 966                 return NT_STATUS_INVALID_HANDLE;
 967
 968         if (lp_strict_sync(SNUM(conn)) &&
 969             (lp_syncalways(SNUM(conn)) || write_through)) {
 970                 int ret = flush_write_cache(fsp, SYNC_FLUSH);
 971                 if (ret == -1) {
 972                         return map_nt_error_from_unix(errno);
 973                 }
 974                 ret = SMB_VFS_FSYNC(fsp);
 975                 if (ret == -1) {
 976                         return map_nt_error_from_unix(errno);
 977                 }
 978         }
 979         return NT_STATUS_OK;
 980 }
 981
 982 /************************************************************
 983  Perform a stat whether a valid fd or not.
 984 ************************************************************/
 985
 986 int fsp_stat(files_struct *fsp)
 987 {
 988         if (fsp->fh->fd == -1) {
 989                 if (fsp->posix_open) {
 990                         return SMB_VFS_LSTAT(fsp->conn, fsp->fsp_name);
 991                 } else {
 992                         return SMB_VFS_STAT(fsp->conn, fsp->fsp_name);
 993                 }
 994         } else {
 995                 return SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st);
 996         }
 997 }