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                         int dosmode;
 316                         trigger_write_time_update(fsp);
 317                         dosmode = dos_mode(fsp->conn, fsp->fsp_name);
 318                         if ((lp_store_dos_attributes(SNUM(fsp->conn)) ||
 319                                         MAP_ARCHIVE(fsp->conn)) &&
 320                                         !IS_DOS_ARCHIVE(dosmode)) {
 321                                 file_set_dosmode(fsp->conn, fsp->fsp_name,
 322                                                  dosmode | aARCH, NULL, false);
 323                         }
 324
 325                         /*
 326                          * If this is the first write and we have an exclusive oplock then setup
 327                          * the write cache.
 328                          */
 329
 330                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
 331                                 setup_write_cache(fsp,
 332                                                  fsp->fsp_name->st.st_ex_size);
 333                                 wcp = fsp->wcp;
 334                         }
 335                 }
 336         }
 337
 338 #ifdef WITH_PROFILE
 339         DO_PROFILE_INC(writecache_total_writes);
 340         if (!fsp->oplock_type) {
 341                 DO_PROFILE_INC(writecache_non_oplock_writes);
 342         }
 343 #endif
 344
 345         /*
 346          * If this file is level II oplocked then we need
 347          * to grab the shared memory lock and inform all
 348          * other files with a level II lock that they need
 349          * to flush their read caches. We keep the lock over
 350          * the shared memory area whilst doing this.
 351          */
 352
 353         /* This should actually be improved to span the write. */
 354         contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
 355         contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
 356
 357 #ifdef WITH_PROFILE
 358         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
 359                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
 360 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
 361                         profile_p->writecache_init_writes,
 362                         profile_p->writecache_abutted_writes,
 363                         profile_p->writecache_total_writes,
 364                         profile_p->writecache_non_oplock_writes,
 365                         profile_p->writecache_allocated_write_caches,
 366                         profile_p->writecache_num_write_caches,
 367                         profile_p->writecache_direct_writes,
 368                         profile_p->writecache_num_perfect_writes,
 369                         profile_p->writecache_read_hits ));
 370
 371                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
 372                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
 373                         profile_p->writecache_flushed_writes[READ_FLUSH],
 374                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
 375                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
 376                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
 377                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
 378                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
 379         }
 380 #endif
 381
 382         if (wcp && req->unread_bytes) {
 383                 /* If we're using receivefile don't
 384                  * deal with a write cache.
 385                  */
 386                 flush_write_cache(fsp, WRITE_FLUSH);
 387                 delete_write_cache(fsp);
 388                 wcp = NULL;
 389         }
 390
 391         if(!wcp) {
 392                 DO_PROFILE_INC(writecache_direct_writes);
 393                 total_written = real_write_file(req, fsp, data, pos, n);
 394                 return total_written;
 395         }
 396
 397         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f "
 398                  "wcp->data_size=%u\n", fsp_str_dbg(fsp), fsp->fh->fd,
 399                  (double)pos, (unsigned int)n, (double)wcp->offset,
 400                  (unsigned int)wcp->data_size));
 401
 402         fsp->fh->pos = pos + n;
 403
 404         /*
 405          * If we have active cache and it isn't contiguous then we flush.
 406          * NOTE: There is a small problem with running out of disk ....
 407          */
 408
 409         if (wcp->data_size) {
 410                 bool cache_flush_needed = False;
 411
 412                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 413
 414                         /* ASCII art.... JRA.
 415
 416       +--------------+-----
 417       | Cached data  | Rest of allocated cache buffer....
 418       +--------------+-----
 419
 420             +-------------------+
 421             | Data to write     |
 422             +-------------------+
 423
 424                         */
 425
 426                         /*
 427                          * Start of write overlaps or abutts the existing data.
 428                          */
 429
 430                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 431
 432                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 433
 434                         /*
 435                          * Update the current buffer size with the new data.
 436                          */
 437
 438                         if(pos + data_used > wcp->offset + wcp->data_size) {
 439                                 wcp->data_size = pos + data_used - wcp->offset;
 440                         }
 441
 442                         /*
 443                          * Update the file size if changed.
 444                          */
 445
 446                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 447                                 if (wcp_file_size_change(fsp) == -1) {
 448                                         return -1;
 449                                 }
 450                         }
 451
 452                         /*
 453                          * If we used all the data then
 454                          * return here.
 455                          */
 456
 457                         if(n == data_used) {
 458                                 return n;
 459                         } else {
 460                                 cache_flush_needed = True;
 461                         }
 462                         /*
 463                          * Move the start of data forward by the amount used,
 464                          * cut down the amount left by the same amount.
 465                          */
 466
 467                         data += data_used;
 468                         pos += data_used;
 469                         n -= data_used;
 470
 471                         DO_PROFILE_INC(writecache_abutted_writes);
 472                         total_written = data_used;
 473
 474                         write_path = 1;
 475
 476                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 477                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 478
 479                         /* ASCII art.... JRA.
 480
 481                         +---------------+
 482                         | Cache buffer  |
 483                         +---------------+
 484
 485             +-------------------+
 486             | Data to write     |
 487             +-------------------+
 488
 489                         */
 490
 491                         /*
 492                          * End of write overlaps the existing data.
 493                          */
 494
 495                         size_t data_used = pos + n - wcp->offset;
 496
 497                         memcpy(wcp->data, data + n - data_used, data_used);
 498
 499                         /*
 500                          * Update the current buffer size with the new data.
 501                          */
 502
 503                         if(pos + n > wcp->offset + wcp->data_size) {
 504                                 wcp->data_size = pos + n - wcp->offset;
 505                         }
 506
 507                         /*
 508                          * Update the file size if changed.
 509                          */
 510
 511                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 512                                 if (wcp_file_size_change(fsp) == -1) {
 513                                         return -1;
 514                                 }
 515                         }
 516
 517                         /*
 518                          * We don't need to move the start of data, but we
 519                          * cut down the amount left by the amount used.
 520                          */
 521
 522                         n -= data_used;
 523
 524                         /*
 525                          * We cannot have used all the data here.
 526                          */
 527
 528                         cache_flush_needed = True;
 529
 530                         DO_PROFILE_INC(writecache_abutted_writes);
 531                         total_written = data_used;
 532
 533                         write_path = 2;
 534
 535                 } else if ( (pos >= wcp->file_size) &&
 536                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 537                                         (pos > wcp->offset + wcp->data_size) &&
 538                                         (pos < wcp->offset + wcp->alloc_size) ) {
 539
 540                         /* ASCII art.... JRA.
 541
 542                        End of file ---->|
 543
 544                         +---------------+---------------+
 545                         | Cached data   | Cache buffer  |
 546                         +---------------+---------------+
 547
 548                                               +-------------------+
 549                                               | Data to write     |
 550                                               +-------------------+
 551
 552                         */
 553
 554                         /*
 555                          * Non-contiguous write part of which fits within
 556                          * the cache buffer and is extending the file
 557                          * and the cache contents reflect the current
 558                          * data up to the current end of the file.
 559                          */
 560
 561                         size_t data_used;
 562
 563                         if(pos + n <= wcp->offset + wcp->alloc_size) {
 564                                 data_used = n;
 565                         } else {
 566                                 data_used = wcp->offset + wcp->alloc_size - pos;
 567                         }
 568
 569                         /*
 570                          * Fill in the non-continuous area with zeros.
 571                          */
 572
 573                         memset(wcp->data + wcp->data_size, '\0',
 574                                 pos - (wcp->offset + wcp->data_size) );
 575
 576                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 577
 578                         /*
 579                          * Update the current buffer size with the new data.
 580                          */
 581
 582                         if(pos + data_used > wcp->offset + wcp->data_size) {
 583                                 wcp->data_size = pos + data_used - wcp->offset;
 584                         }
 585
 586                         /*
 587                          * Update the file size if changed.
 588                          */
 589
 590                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 591                                 if (wcp_file_size_change(fsp) == -1) {
 592                                         return -1;
 593                                 }
 594                         }
 595
 596                         /*
 597                          * If we used all the data then
 598                          * return here.
 599                          */
 600
 601                         if(n == data_used) {
 602                                 return n;
 603                         } else {
 604                                 cache_flush_needed = True;
 605                         }
 606
 607                         /*
 608                          * Move the start of data forward by the amount used,
 609                          * cut down the amount left by the same amount.
 610                          */
 611
 612                         data += data_used;
 613                         pos += data_used;
 614                         n -= data_used;
 615
 616                         DO_PROFILE_INC(writecache_abutted_writes);
 617                         total_written = data_used;
 618
 619                         write_path = 3;
 620
 621                 } else if ( (pos >= wcp->file_size) &&
 622                             (n == 1) &&
 623                             (wcp->file_size == wcp->offset + wcp->data_size) &&
 624                             (pos < wcp->file_size + wcp->alloc_size)) {
 625
 626                         /*
 627
 628                 End of file ---->|
 629
 630                  +---------------+---------------+
 631                  | Cached data   | Cache buffer  |
 632                  +---------------+---------------+
 633
 634                                  |<------- allocated size ---------------->|
 635
 636                                                          +--------+
 637                                                          | 1 Byte |
 638                                                          +--------+
 639
 640                         MS-Office seems to do this a lot to determine if there's enough
 641                         space on the filesystem to write a new file.
 642
 643                         Change to :
 644
 645                 End of file ---->|
 646                                  +-----------------------+--------+
 647                                  | Zeroed Cached data    | 1 Byte |
 648                                  +-----------------------+--------+
 649                         */
 650
 651                         flush_write_cache(fsp, WRITE_FLUSH);
 652                         wcp->offset = wcp->file_size;
 653                         wcp->data_size = pos - wcp->file_size + 1;
 654                         memset(wcp->data, '\0', wcp->data_size);
 655                         memcpy(wcp->data + wcp->data_size-1, data, 1);
 656
 657                         /*
 658                          * Update the file size if changed.
 659                          */
 660
 661                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 662                                 if (wcp_file_size_change(fsp) == -1) {
 663                                         return -1;
 664                                 }
 665                         }
 666
 667                         return n;
 668
 669                 } else {
 670
 671                         /* ASCII art..... JRA.
 672
 673    Case 1).
 674
 675                         +---------------+---------------+
 676                         | Cached data   | Cache buffer  |
 677                         +---------------+---------------+
 678
 679                                                               +-------------------+
 680                                                               | Data to write     |
 681                                                               +-------------------+
 682
 683    Case 2).
 684
 685                            +---------------+---------------+
 686                            | Cached data   | Cache buffer  |
 687                            +---------------+---------------+
 688
 689    +-------------------+
 690    | Data to write     |
 691    +-------------------+
 692
 693     Case 3).
 694
 695                            +---------------+---------------+
 696                            | Cached data   | Cache buffer  |
 697                            +---------------+---------------+
 698
 699                   +-----------------------------------------------------+
 700                   | Data to write                                       |
 701                   +-----------------------------------------------------+
 702
 703                   */
 704
 705                         /*
 706                          * Write is bigger than buffer, or there is no overlap on the
 707                          * low or high ends.
 708                          */
 709
 710                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 711 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 712
 713                         /*
 714                          * If write would fit in the cache, and is larger than
 715                          * the data already in the cache, flush the cache and
 716                          * preferentially copy the data new data into it. Otherwise
 717                          * just write the data directly.
 718                          */
 719
 720                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 721                                 cache_flush_needed = True;
 722                         } else {
 723                                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
 724
 725                                 /*
 726                                  * If the write overlaps the entire cache, then
 727                                  * discard the current contents of the cache.
 728                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 729                                  */
 730
 731                                 if ((pos <= wcp->offset) &&
 732                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 733                                         DEBUG(9,("write_file: discarding overwritten write \
 734 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 735                                         wcp->data_size = 0;
 736                                 }
 737
 738                                 DO_PROFILE_INC(writecache_direct_writes);
 739                                 if (ret == -1) {
 740                                         return ret;
 741                                 }
 742
 743                                 if (pos + ret > wcp->file_size) {
 744                                         wcp->file_size = pos + ret;
 745                                 }
 746
 747                                 return ret;
 748                         }
 749
 750                         write_path = 4;
 751
 752                 }
 753
 754                 if (cache_flush_needed) {
 755                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 756 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 757                                 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 758                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 759
 760                         flush_write_cache(fsp, WRITE_FLUSH);
 761                 }
 762         }
 763
 764         /*
 765          * If the write request is bigger than the cache
 766          * size, write it all out.
 767          */
 768
 769         if (n > wcp->alloc_size ) {
 770                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
 771                 if (ret == -1) {
 772                         return -1;
 773                 }
 774
 775                 if (pos + ret > wcp->file_size) {
 776                         wcp->file_size = pos + n;
 777                 }
 778
 779                 DO_PROFILE_INC(writecache_direct_writes);
 780                 return total_written + n;
 781         }
 782
 783         /*
 784          * If there's any data left, cache it.
 785          */
 786
 787         if (n) {
 788 #ifdef WITH_PROFILE
 789                 if (wcp->data_size) {
 790                         DO_PROFILE_INC(writecache_abutted_writes);
 791                 } else {
 792                         DO_PROFILE_INC(writecache_init_writes);
 793                 }
 794 #endif
 795                 memcpy(wcp->data+wcp->data_size, data, n);
 796                 if (wcp->data_size == 0) {
 797                         wcp->offset = pos;
 798                         DO_PROFILE_INC(writecache_num_write_caches);
 799                 }
 800                 wcp->data_size += n;
 801
 802                 /*
 803                  * Update the file size if changed.
 804                  */
 805
 806                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 807                         if (wcp_file_size_change(fsp) == -1) {
 808                                 return -1;
 809                         }
 810                 }
 811                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 812                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 813
 814                 total_written += n;
 815                 return total_written; /* .... that's a write :) */
 816         }
 817
 818         return total_written;
 819 }
 820
 821 /****************************************************************************
 822  Delete the write cache structure.
 823 ****************************************************************************/
 824
 825 void delete_write_cache(files_struct *fsp)
 826 {
 827         write_cache *wcp;
 828
 829         if(!fsp) {
 830                 return;
 831         }
 832
 833         if(!(wcp = fsp->wcp)) {
 834                 return;
 835         }
 836
 837         DO_PROFILE_DEC(writecache_allocated_write_caches);
 838         allocated_write_caches--;
 839
 840         SMB_ASSERT(wcp->data_size == 0);
 841
 842         SAFE_FREE(wcp->data);
 843         SAFE_FREE(fsp->wcp);
 844
 845         DEBUG(10,("delete_write_cache: File %s deleted write cache\n",
 846                   fsp_str_dbg(fsp)));
 847 }
 848
 849 /****************************************************************************
 850  Setup the write cache structure.
 851 ****************************************************************************/
 852
 853 static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 854 {
 855         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 856         write_cache *wcp;
 857
 858         if (allocated_write_caches >= MAX_WRITE_CACHES) {
 859                 return False;
 860         }
 861
 862         if(alloc_size == 0 || fsp->wcp) {
 863                 return False;
 864         }
 865
 866         if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
 867                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 868                 return False;
 869         }
 870
 871         wcp->file_size = file_size;
 872         wcp->offset = 0;
 873         wcp->alloc_size = alloc_size;
 874         wcp->data_size = 0;
 875         if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
 876                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 877                         (unsigned int)wcp->alloc_size ));
 878                 SAFE_FREE(wcp);
 879                 return False;
 880         }
 881
 882         memset(wcp->data, '\0', wcp->alloc_size );
 883
 884         fsp->wcp = wcp;
 885         DO_PROFILE_INC(writecache_allocated_write_caches);
 886         allocated_write_caches++;
 887
 888         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 889                   fsp_str_dbg(fsp), (unsigned long)wcp->alloc_size));
 890
 891         return True;
 892 }
 893
 894 /****************************************************************************
 895  Cope with a size change.
 896 ****************************************************************************/
 897
 898 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
 899 {
 900         if(fsp->wcp) {
 901                 /* The cache *must* have been flushed before we do this. */
 902                 if (fsp->wcp->data_size != 0) {
 903                         char *msg;
 904                         if (asprintf(&msg, "set_filelen_write_cache: size change "
 905                                  "on file %s with write cache size = %lu\n",
 906                                  fsp->fsp_name->base_name,
 907                                  (unsigned long)fsp->wcp->data_size) != -1) {
 908                                 smb_panic(msg);
 909                         } else {
 910                                 smb_panic("set_filelen_write_cache");
 911                         }
 912                 }
 913                 fsp->wcp->file_size = file_size;
 914         }
 915 }
 916
 917 /*******************************************************************
 918  Flush a write cache struct to disk.
 919 ********************************************************************/
 920
 921 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 922 {
 923         write_cache *wcp = fsp->wcp;
 924         size_t data_size;
 925         ssize_t ret;
 926
 927         if(!wcp || !wcp->data_size) {
 928                 return 0;
 929         }
 930
 931         data_size = wcp->data_size;
 932         wcp->data_size = 0;
 933
 934         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
 935
 936         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
 937                 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
 938
 939 #ifdef WITH_PROFILE
 940         if(data_size == wcp->alloc_size) {
 941                 DO_PROFILE_INC(writecache_num_perfect_writes);
 942         }
 943 #endif
 944
 945         ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
 946
 947         /*
 948          * Ensure file size if kept up to date if write extends file.
 949          */
 950
 951         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
 952                 wcp->file_size = wcp->offset + ret;
 953         }
 954
 955         return ret;
 956 }
 957
 958 /*******************************************************************
 959 sync a file
 960 ********************************************************************/
 961
 962 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
 963 {
 964         if (fsp->fh->fd == -1)
 965                 return NT_STATUS_INVALID_HANDLE;
 966
 967         if (lp_strict_sync(SNUM(conn)) &&
 968             (lp_syncalways(SNUM(conn)) || write_through)) {
 969                 int ret = flush_write_cache(fsp, SYNC_FLUSH);
 970                 if (ret == -1) {
 971                         return map_nt_error_from_unix(errno);
 972                 }
 973                 ret = SMB_VFS_FSYNC(fsp);
 974                 if (ret == -1) {
 975                         return map_nt_error_from_unix(errno);
 976                 }
 977         }
 978         return NT_STATUS_OK;
 979 }
 980
 981 /************************************************************
 982  Perform a stat whether a valid fd or not.
 983 ************************************************************/
 984
 985 int fsp_stat(files_struct *fsp)
 986 {
 987         if (fsp->fh->fd == -1) {
 988                 if (fsp->posix_open) {
 989                         return SMB_VFS_LSTAT(fsp->conn, fsp->fsp_name);
 990                 } else {
 991                         return SMB_VFS_STAT(fsp->conn, fsp->fsp_name);
 992                 }
 993         } else {
 994                 return SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st);
 995         }
 996 }