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 "printing.h"
  24 #include "smbd/smbd.h"
  25 #include "smbd/globals.h"
  26 #include "smbprofile.h"
  27
  28 struct write_cache {
  29         off_t file_size;
  30         off_t offset;
  31         size_t alloc_size;
  32         size_t data_size;
  33         char *data;
  34 };
  35
  36 static bool setup_write_cache(files_struct *, off_t);
  37
  38 /****************************************************************************
  39  Read from write cache if we can.
  40 ****************************************************************************/
  41
  42 static bool read_from_write_cache(files_struct *fsp,char *data,off_t pos,size_t n)
  43 {
  44         struct write_cache *wcp = fsp->wcp;
  45
  46         if(!wcp) {
  47                 return False;
  48         }
  49
  50         if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) {
  51                 return False;
  52         }
  53
  54         memcpy(data, wcp->data + (pos - wcp->offset), n);
  55
  56         DO_PROFILE_INC(writecache_cached_reads);
  57
  58         return True;
  59 }
  60
  61 /****************************************************************************
  62  Read from a file.
  63 ****************************************************************************/
  64
  65 ssize_t read_file(files_struct *fsp,char *data,off_t pos,size_t n)
  66 {
  67         ssize_t ret = 0;
  68
  69         /* you can't read from print files */
  70         if (fsp->print_file) {
  71                 errno = EBADF;
  72                 return -1;
  73         }
  74
  75         /*
  76          * Serve from write cache if we can.
  77          */
  78
  79         if(read_from_write_cache(fsp, data, pos, n)) {
  80                 fsp->fh->pos = pos + n;
  81                 fsp->fh->position_information = fsp->fh->pos;
  82                 return n;
  83         }
  84
  85         flush_write_cache(fsp, SAMBA_READ_FLUSH);
  86
  87         fsp->fh->pos = pos;
  88
  89         if (n > 0) {
  90                 ret = SMB_VFS_PREAD(fsp,data,n,pos);
  91
  92                 if (ret == -1) {
  93                         return -1;
  94                 }
  95         }
  96
  97         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
  98                   fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
  99
 100         fsp->fh->pos += ret;
 101         fsp->fh->position_information = fsp->fh->pos;
 102
 103         return(ret);
 104 }
 105
 106 /****************************************************************************
 107  *Really* write to a file.
 108 ****************************************************************************/
 109
 110 static ssize_t real_write_file(struct smb_request *req,
 111                                 files_struct *fsp,
 112                                 const char *data,
 113                                 off_t pos,
 114                                 size_t n)
 115 {
 116         ssize_t ret;
 117
 118         if (pos == -1) {
 119                 ret = vfs_write_data(req, fsp, data, n);
 120         } else {
 121                 fsp->fh->pos = pos;
 122                 if (pos && lp_strict_allocate(SNUM(fsp->conn) &&
 123                                 !fsp->is_sparse)) {
 124                         if (vfs_fill_sparse(fsp, pos) == -1) {
 125                                 return -1;
 126                         }
 127                 }
 128                 ret = vfs_pwrite_data(req, fsp, data, n, pos);
 129         }
 130
 131         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 132                   fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
 133
 134         if (ret != -1) {
 135                 fsp->fh->pos += ret;
 136
 137 /* Yes - this is correct - writes don't update this. JRA. */
 138 /* Found by Samba4 tests. */
 139 #if 0
 140                 fsp->position_information = fsp->pos;
 141 #endif
 142         }
 143
 144         return ret;
 145 }
 146
 147 /****************************************************************************
 148  File size cache change.
 149  Updates size on disk but doesn't flush the cache.
 150 ****************************************************************************/
 151
 152 static int wcp_file_size_change(files_struct *fsp)
 153 {
 154         int ret;
 155         struct write_cache *wcp = fsp->wcp;
 156
 157         wcp->file_size = wcp->offset + wcp->data_size;
 158         ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
 159         if (ret == -1) {
 160                 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f "
 161                          "error %s\n", fsp_str_dbg(fsp),
 162                          (double)wcp->file_size, strerror(errno)));
 163         }
 164         return ret;
 165 }
 166
 167 void update_write_time_handler(struct tevent_context *ctx,
 168                                       struct tevent_timer *te,
 169                                       struct timeval now,
 170                                       void *private_data)
 171 {
 172         files_struct *fsp = (files_struct *)private_data;
 173
 174         DEBUG(5, ("Update write time on %s\n", fsp_str_dbg(fsp)));
 175
 176         /* change the write time in the open file db. */
 177         (void)set_write_time(fsp->file_id, timespec_current());
 178
 179         /* And notify. */
 180         notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
 181                      FILE_NOTIFY_CHANGE_LAST_WRITE, fsp->fsp_name->base_name);
 182
 183         /* Remove the timed event handler. */
 184         TALLOC_FREE(fsp->update_write_time_event);
 185 }
 186
 187 /*********************************************************
 188  Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
 189  in the future.
 190 *********************************************************/
 191
 192 void trigger_write_time_update(struct files_struct *fsp)
 193 {
 194         int delay;
 195
 196         if (fsp->posix_open) {
 197                 /* Don't use delayed writes on POSIX files. */
 198                 return;
 199         }
 200
 201         if (fsp->write_time_forced) {
 202                 /* No point - "sticky" write times
 203                  * in effect.
 204                  */
 205                 return;
 206         }
 207
 208         /* We need to remember someone did a write
 209          * and update to current time on close. */
 210
 211         fsp->update_write_time_on_close = true;
 212
 213         if (fsp->update_write_time_triggered) {
 214                 /*
 215                  * We only update the write time after 2 seconds
 216                  * on the first normal write. After that
 217                  * no other writes affect this until close.
 218                  */
 219                 return;
 220         }
 221         fsp->update_write_time_triggered = true;
 222
 223         delay = lp_parm_int(SNUM(fsp->conn),
 224                             "smbd", "writetimeupdatedelay",
 225                             WRITE_TIME_UPDATE_USEC_DELAY);
 226
 227         DEBUG(5, ("Update write time %d usec later on %s\n",
 228                   delay, fsp_str_dbg(fsp)));
 229
 230         /* trigger the update 2 seconds later */
 231         fsp->update_write_time_event =
 232                 tevent_add_timer(fsp->conn->sconn->ev_ctx, NULL,
 233                                  timeval_current_ofs_usec(delay),
 234                                  update_write_time_handler, fsp);
 235 }
 236
 237 void trigger_write_time_update_immediate(struct files_struct *fsp)
 238 {
 239         struct smb_file_time ft;
 240
 241         if (fsp->posix_open) {
 242                 /* Don't use delayed writes on POSIX files. */
 243                 return;
 244         }
 245
 246         if (fsp->write_time_forced) {
 247                 /*
 248                  * No point - "sticky" write times
 249                  * in effect.
 250                  */
 251                 return;
 252         }
 253
 254         TALLOC_FREE(fsp->update_write_time_event);
 255         DEBUG(5, ("Update write time immediate on %s\n",
 256                   fsp_str_dbg(fsp)));
 257
 258         /* After an immediate update, reset the trigger. */
 259         fsp->update_write_time_triggered = true;
 260         fsp->update_write_time_on_close = false;
 261
 262         ZERO_STRUCT(ft);
 263         ft.mtime = timespec_current();
 264
 265         /* Update the time in the open file db. */
 266         (void)set_write_time(fsp->file_id, ft.mtime);
 267
 268         /* Now set on disk - takes care of notify. */
 269         (void)smb_set_file_time(fsp->conn, fsp, fsp->fsp_name, &ft, false);
 270 }
 271
 272 void mark_file_modified(files_struct *fsp)
 273 {
 274         int dosmode;
 275
 276         if (fsp->modified) {
 277                 return;
 278         }
 279
 280         fsp->modified = true;
 281
 282         if (SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st) != 0) {
 283                 return;
 284         }
 285         trigger_write_time_update(fsp);
 286
 287         if (fsp->posix_open) {
 288                 return;
 289         }
 290         if (!(lp_store_dos_attributes(SNUM(fsp->conn)) ||
 291               MAP_ARCHIVE(fsp->conn))) {
 292                 return;
 293         }
 294
 295         dosmode = dos_mode(fsp->conn, fsp->fsp_name);
 296         if (IS_DOS_ARCHIVE(dosmode)) {
 297                 return;
 298         }
 299         file_set_dosmode(fsp->conn, fsp->fsp_name,
 300                          dosmode | FILE_ATTRIBUTE_ARCHIVE, NULL, false);
 301 }
 302
 303 /****************************************************************************
 304  Write to a file.
 305 ****************************************************************************/
 306
 307 ssize_t write_file(struct smb_request *req,
 308                         files_struct *fsp,
 309                         const char *data,
 310                         off_t pos,
 311                         size_t n)
 312 {
 313         struct write_cache *wcp = fsp->wcp;
 314         ssize_t total_written = 0;
 315         int write_path = -1;
 316
 317         if (fsp->print_file) {
 318                 uint32_t t;
 319                 int ret;
 320
 321                 ret = print_spool_write(fsp, data, n, pos, &t);
 322                 if (ret) {
 323                         errno = ret;
 324                         return -1;
 325                 }
 326                 return t;
 327         }
 328
 329         if (!fsp->can_write) {
 330                 errno = EPERM;
 331                 return -1;
 332         }
 333
 334         /*
 335          * If this is the first write and we have an exclusive oplock
 336          * then setup the write cache.
 337          */
 338
 339         if (!fsp->modified &&
 340             EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) &&
 341             (wcp == NULL)) {
 342                 /*
 343                  * Note: no write cache with leases!
 344                  * as the handles would have to share the write cache
 345                  * that's possible but an improvement for another day...
 346                  */
 347                 setup_write_cache(fsp, fsp->fsp_name->st.st_ex_size);
 348                 wcp = fsp->wcp;
 349         }
 350
 351         mark_file_modified(fsp);
 352
 353         DO_PROFILE_INC(writecache_total_writes);
 354         if (!fsp->oplock_type) {
 355                 DO_PROFILE_INC(writecache_non_oplock_writes);
 356         }
 357
 358         /*
 359          * If this file is level II oplocked then we need
 360          * to grab the shared memory lock and inform all
 361          * other files with a level II lock that they need
 362          * to flush their read caches. We keep the lock over
 363          * the shared memory area whilst doing this.
 364          */
 365
 366         /* This should actually be improved to span the write. */
 367         contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
 368         contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
 369
 370         if (wcp && req->unread_bytes) {
 371                 /* If we're using receivefile don't
 372                  * deal with a write cache.
 373                  */
 374                 flush_write_cache(fsp, SAMBA_WRITE_FLUSH);
 375                 delete_write_cache(fsp);
 376                 wcp = NULL;
 377         }
 378
 379         if(!wcp) {
 380                 DO_PROFILE_INC(writecache_direct_writes);
 381                 total_written = real_write_file(req, fsp, data, pos, n);
 382                 return total_written;
 383         }
 384
 385         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f "
 386                  "wcp->data_size=%u\n", fsp_str_dbg(fsp), fsp->fh->fd,
 387                  (double)pos, (unsigned int)n, (double)wcp->offset,
 388                  (unsigned int)wcp->data_size));
 389
 390         fsp->fh->pos = pos + n;
 391
 392         if ((n == 1) && (data[0] == '\0') && (pos > wcp->file_size)) {
 393                 int ret;
 394
 395                 /*
 396                  * This is a 1-byte write of a 0 beyond the EOF and
 397                  * thus implicitly also beyond the current active
 398                  * write cache, the typical file-extending (and
 399                  * allocating, but we're using the write cache here)
 400                  * write done by Windows. We just have to ftruncate
 401                  * the file and rely on posix semantics to return
 402                  * zeros for non-written file data that is within the
 403                  * file length.
 404                  *
 405                  * We can not use wcp_file_size_change here because we
 406                  * might have an existing write cache, and
 407                  * wcp_file_size_change assumes a change to just the
 408                  * end of the current write cache.
 409                  */
 410
 411                 wcp->file_size = pos + 1;
 412                 ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
 413                 if (ret == -1) {
 414                         DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f"
 415                                  "error %s\n", fsp_str_dbg(fsp),
 416                                  (double)wcp->file_size, strerror(errno)));
 417                         return -1;
 418                 }
 419                 return 1;
 420         }
 421
 422
 423         /*
 424          * If we have active cache and it isn't contiguous then we flush.
 425          * NOTE: There is a small problem with running out of disk ....
 426          */
 427
 428         if (wcp->data_size) {
 429                 bool cache_flush_needed = False;
 430
 431                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
 432
 433                         /* ASCII art.... JRA.
 434
 435       +--------------+-----
 436       | Cached data  | Rest of allocated cache buffer....
 437       +--------------+-----
 438
 439             +-------------------+
 440             | Data to write     |
 441             +-------------------+
 442
 443                         */
 444
 445                         /*
 446                          * Start of write overlaps or abutts the existing data.
 447                          */
 448
 449                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
 450
 451                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 452
 453                         /*
 454                          * Update the current buffer size with the new data.
 455                          */
 456
 457                         if(pos + data_used > wcp->offset + wcp->data_size) {
 458                                 wcp->data_size = pos + data_used - wcp->offset;
 459                         }
 460
 461                         /*
 462                          * Update the file size if changed.
 463                          */
 464
 465                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 466                                 if (wcp_file_size_change(fsp) == -1) {
 467                                         return -1;
 468                                 }
 469                         }
 470
 471                         /*
 472                          * If we used all the data then
 473                          * return here.
 474                          */
 475
 476                         if(n == data_used) {
 477                                 return n;
 478                         } else {
 479                                 cache_flush_needed = True;
 480                         }
 481                         /*
 482                          * Move the start of data forward by the amount used,
 483                          * cut down the amount left by the same amount.
 484                          */
 485
 486                         data += data_used;
 487                         pos += data_used;
 488                         n -= data_used;
 489
 490                         DO_PROFILE_INC(writecache_abutted_writes);
 491                         total_written = data_used;
 492
 493                         write_path = 1;
 494
 495                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
 496                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
 497
 498                         /* ASCII art.... JRA.
 499
 500                         +---------------+
 501                         | Cache buffer  |
 502                         +---------------+
 503
 504             +-------------------+
 505             | Data to write     |
 506             +-------------------+
 507
 508                         */
 509
 510                         /*
 511                          * End of write overlaps the existing data.
 512                          */
 513
 514                         size_t data_used = pos + n - wcp->offset;
 515
 516                         memcpy(wcp->data, data + n - data_used, data_used);
 517
 518                         /*
 519                          * Update the current buffer size with the new data.
 520                          */
 521
 522                         if(pos + n > wcp->offset + wcp->data_size) {
 523                                 wcp->data_size = pos + n - wcp->offset;
 524                         }
 525
 526                         /*
 527                          * Update the file size if changed.
 528                          */
 529
 530                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 531                                 if (wcp_file_size_change(fsp) == -1) {
 532                                         return -1;
 533                                 }
 534                         }
 535
 536                         /*
 537                          * We don't need to move the start of data, but we
 538                          * cut down the amount left by the amount used.
 539                          */
 540
 541                         n -= data_used;
 542
 543                         /*
 544                          * We cannot have used all the data here.
 545                          */
 546
 547                         cache_flush_needed = True;
 548
 549                         DO_PROFILE_INC(writecache_abutted_writes);
 550                         total_written = data_used;
 551
 552                         write_path = 2;
 553
 554                 } else if ( (pos >= wcp->file_size) &&
 555                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
 556                                         (pos > wcp->offset + wcp->data_size) &&
 557                                         (pos < wcp->offset + wcp->alloc_size) ) {
 558
 559                         /* ASCII art.... JRA.
 560
 561                        End of file ---->|
 562
 563                         +---------------+---------------+
 564                         | Cached data   | Cache buffer  |
 565                         +---------------+---------------+
 566
 567                                               +-------------------+
 568                                               | Data to write     |
 569                                               +-------------------+
 570
 571                         */
 572
 573                         /*
 574                          * Non-contiguous write part of which fits within
 575                          * the cache buffer and is extending the file
 576                          * and the cache contents reflect the current
 577                          * data up to the current end of the file.
 578                          */
 579
 580                         size_t data_used;
 581
 582                         if(pos + n <= wcp->offset + wcp->alloc_size) {
 583                                 data_used = n;
 584                         } else {
 585                                 data_used = wcp->offset + wcp->alloc_size - pos;
 586                         }
 587
 588                         /*
 589                          * Fill in the non-continuous area with zeros.
 590                          */
 591
 592                         memset(wcp->data + wcp->data_size, '\0',
 593                                 pos - (wcp->offset + wcp->data_size) );
 594
 595                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
 596
 597                         /*
 598                          * Update the current buffer size with the new data.
 599                          */
 600
 601                         if(pos + data_used > wcp->offset + wcp->data_size) {
 602                                 wcp->data_size = pos + data_used - wcp->offset;
 603                         }
 604
 605                         /*
 606                          * Update the file size if changed.
 607                          */
 608
 609                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 610                                 if (wcp_file_size_change(fsp) == -1) {
 611                                         return -1;
 612                                 }
 613                         }
 614
 615                         /*
 616                          * If we used all the data then
 617                          * return here.
 618                          */
 619
 620                         if(n == data_used) {
 621                                 return n;
 622                         } else {
 623                                 cache_flush_needed = True;
 624                         }
 625
 626                         /*
 627                          * Move the start of data forward by the amount used,
 628                          * cut down the amount left by the same amount.
 629                          */
 630
 631                         data += data_used;
 632                         pos += data_used;
 633                         n -= data_used;
 634
 635                         DO_PROFILE_INC(writecache_abutted_writes);
 636                         total_written = data_used;
 637
 638                         write_path = 3;
 639
 640                 } else if ( (pos >= wcp->file_size) &&
 641                             (n == 1) &&
 642                             (wcp->file_size == wcp->offset + wcp->data_size) &&
 643                             (pos < wcp->file_size + wcp->alloc_size)) {
 644
 645                         /*
 646
 647                 End of file ---->|
 648
 649                  +---------------+---------------+
 650                  | Cached data   | Cache buffer  |
 651                  +---------------+---------------+
 652
 653                                  |<------- allocated size ---------------->|
 654
 655                                                          +--------+
 656                                                          | 1 Byte |
 657                                                          +--------+
 658
 659                         MS-Office seems to do this a lot to determine if there's enough
 660                         space on the filesystem to write a new file.
 661
 662                         Change to :
 663
 664                 End of file ---->|
 665                                  +-----------------------+--------+
 666                                  | Zeroed Cached data    | 1 Byte |
 667                                  +-----------------------+--------+
 668                         */
 669
 670                         flush_write_cache(fsp, SAMBA_WRITE_FLUSH);
 671                         wcp->offset = wcp->file_size;
 672                         wcp->data_size = pos - wcp->file_size + 1;
 673                         memset(wcp->data, '\0', wcp->data_size);
 674                         memcpy(wcp->data + wcp->data_size-1, data, 1);
 675
 676                         /*
 677                          * Update the file size if changed.
 678                          */
 679
 680                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 681                                 if (wcp_file_size_change(fsp) == -1) {
 682                                         return -1;
 683                                 }
 684                         }
 685
 686                         return n;
 687
 688                 } else {
 689
 690                         /* ASCII art..... JRA.
 691
 692    Case 1).
 693
 694                         +---------------+---------------+
 695                         | Cached data   | Cache buffer  |
 696                         +---------------+---------------+
 697
 698                                                               +-------------------+
 699                                                               | Data to write     |
 700                                                               +-------------------+
 701
 702    Case 2).
 703
 704                            +---------------+---------------+
 705                            | Cached data   | Cache buffer  |
 706                            +---------------+---------------+
 707
 708    +-------------------+
 709    | Data to write     |
 710    +-------------------+
 711
 712     Case 3).
 713
 714                            +---------------+---------------+
 715                            | Cached data   | Cache buffer  |
 716                            +---------------+---------------+
 717
 718                   +-----------------------------------------------------+
 719                   | Data to write                                       |
 720                   +-----------------------------------------------------+
 721
 722                   */
 723
 724                         /*
 725                          * Write is bigger than buffer, or there is no overlap on the
 726                          * low or high ends.
 727                          */
 728
 729                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
 730 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
 731
 732                         /*
 733                          * If write would fit in the cache, and is larger than
 734                          * the data already in the cache, flush the cache and
 735                          * preferentially copy the data new data into it. Otherwise
 736                          * just write the data directly.
 737                          */
 738
 739                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 740                                 cache_flush_needed = True;
 741                         } else {
 742                                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
 743
 744                                 /*
 745                                  * If the write overlaps the entire cache, then
 746                                  * discard the current contents of the cache.
 747                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
 748                                  */
 749
 750                                 if ((pos <= wcp->offset) &&
 751                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
 752                                         DEBUG(9,("write_file: discarding overwritten write \
 753 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
 754                                         wcp->data_size = 0;
 755                                 }
 756
 757                                 DO_PROFILE_INC(writecache_direct_writes);
 758                                 if (ret == -1) {
 759                                         return ret;
 760                                 }
 761
 762                                 if (pos + ret > wcp->file_size) {
 763                                         wcp->file_size = pos + ret;
 764                                 }
 765
 766                                 return ret;
 767                         }
 768
 769                         write_path = 4;
 770
 771                 }
 772
 773                 if (cache_flush_needed) {
 774                         DEBUG(3,("SAMBA_WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
 775 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
 776                                 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
 777                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
 778
 779                         flush_write_cache(fsp, SAMBA_WRITE_FLUSH);
 780                 }
 781         }
 782
 783         /*
 784          * If the write request is bigger than the cache
 785          * size, write it all out.
 786          */
 787
 788         if (n > wcp->alloc_size ) {
 789                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
 790                 if (ret == -1) {
 791                         return -1;
 792                 }
 793
 794                 if (pos + ret > wcp->file_size) {
 795                         wcp->file_size = pos + n;
 796                 }
 797
 798                 DO_PROFILE_INC(writecache_direct_writes);
 799                 return total_written + n;
 800         }
 801
 802         /*
 803          * If there's any data left, cache it.
 804          */
 805
 806         if (n) {
 807                 DO_PROFILE_INC(writecache_cached_writes);
 808                 if (wcp->data_size) {
 809                         DO_PROFILE_INC(writecache_abutted_writes);
 810                 } else {
 811                         DO_PROFILE_INC(writecache_init_writes);
 812                 }
 813
 814                 if ((wcp->data_size == 0)
 815                     && (pos > wcp->file_size)
 816                     && (pos + n <= wcp->file_size + wcp->alloc_size)) {
 817                         /*
 818                          * This is a write completely beyond the
 819                          * current EOF, but within reach of the write
 820                          * cache. We expect fill-up writes pretty
 821                          * soon, so it does not make sense to start
 822                          * the write cache at the current
 823                          * offset. These fill-up writes would trigger
 824                          * separate pwrites or even unnecessary cache
 825                          * flushes because they overlap if this is a
 826                          * one-byte allocating write.
 827                          */
 828                         wcp->offset = wcp->file_size;
 829                         wcp->data_size = pos - wcp->file_size;
 830                         memset(wcp->data, 0, wcp->data_size);
 831                 }
 832
 833                 memcpy(wcp->data+wcp->data_size, data, n);
 834                 if (wcp->data_size == 0) {
 835                         wcp->offset = pos;
 836                 }
 837                 wcp->data_size += n;
 838
 839                 /*
 840                  * Update the file size if changed.
 841                  */
 842
 843                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 844                         if (wcp_file_size_change(fsp) == -1) {
 845                                 return -1;
 846                         }
 847                 }
 848                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
 849                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
 850
 851                 total_written += n;
 852                 return total_written; /* .... that's a write :) */
 853         }
 854
 855         return total_written;
 856 }
 857
 858 /****************************************************************************
 859  Delete the write cache structure.
 860 ****************************************************************************/
 861
 862 void delete_write_cache(files_struct *fsp)
 863 {
 864         struct write_cache *wcp;
 865
 866         if(!fsp) {
 867                 return;
 868         }
 869
 870         if(!(wcp = fsp->wcp)) {
 871                 return;
 872         }
 873
 874         DO_PROFILE_INC(writecache_deallocations);
 875         allocated_write_caches--;
 876
 877         SMB_ASSERT(wcp->data_size == 0);
 878
 879         SAFE_FREE(wcp->data);
 880         SAFE_FREE(fsp->wcp);
 881
 882         DEBUG(10,("delete_write_cache: File %s deleted write cache\n",
 883                   fsp_str_dbg(fsp)));
 884 }
 885
 886 /****************************************************************************
 887  Setup the write cache structure.
 888 ****************************************************************************/
 889
 890 static bool setup_write_cache(files_struct *fsp, off_t file_size)
 891 {
 892         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 893         struct write_cache *wcp;
 894
 895         if (allocated_write_caches >= MAX_WRITE_CACHES) {
 896                 return False;
 897         }
 898
 899         if(alloc_size == 0 || fsp->wcp) {
 900                 return False;
 901         }
 902
 903         if((wcp = SMB_MALLOC_P(struct write_cache)) == NULL) {
 904                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 905                 return False;
 906         }
 907
 908         wcp->file_size = file_size;
 909         wcp->offset = 0;
 910         wcp->alloc_size = alloc_size;
 911         wcp->data_size = 0;
 912         if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
 913                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 914                         (unsigned int)wcp->alloc_size ));
 915                 SAFE_FREE(wcp);
 916                 return False;
 917         }
 918
 919         memset(wcp->data, '\0', wcp->alloc_size );
 920
 921         fsp->wcp = wcp;
 922         DO_PROFILE_INC(writecache_allocations);
 923         allocated_write_caches++;
 924
 925         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 926                   fsp_str_dbg(fsp), (unsigned long)wcp->alloc_size));
 927
 928         return True;
 929 }
 930
 931 /****************************************************************************
 932  Cope with a size change.
 933 ****************************************************************************/
 934
 935 void set_filelen_write_cache(files_struct *fsp, off_t file_size)
 936 {
 937         if(fsp->wcp) {
 938                 /* The cache *must* have been flushed before we do this. */
 939                 if (fsp->wcp->data_size != 0) {
 940                         char *msg;
 941                         if (asprintf(&msg, "set_filelen_write_cache: size change "
 942                                  "on file %s with write cache size = %lu\n",
 943                                  fsp->fsp_name->base_name,
 944                                  (unsigned long)fsp->wcp->data_size) != -1) {
 945                                 smb_panic(msg);
 946                         } else {
 947                                 smb_panic("set_filelen_write_cache");
 948                         }
 949                 }
 950                 fsp->wcp->file_size = file_size;
 951         }
 952 }
 953
 954 /*******************************************************************
 955  Flush a write cache struct to disk.
 956 ********************************************************************/
 957
 958 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 959 {
 960         struct write_cache *wcp = fsp->wcp;
 961         size_t data_size;
 962         ssize_t ret;
 963
 964         if(!wcp || !wcp->data_size) {
 965                 return 0;
 966         }
 967
 968         data_size = wcp->data_size;
 969         wcp->data_size = 0;
 970
 971         switch (reason) {
 972         case SAMBA_SEEK_FLUSH:
 973                 DO_PROFILE_INC(writecache_flush_reason_seek);
 974                 break;
 975         case SAMBA_READ_FLUSH:
 976                 DO_PROFILE_INC(writecache_flush_reason_read);
 977                 break;
 978         case SAMBA_WRITE_FLUSH:
 979                 DO_PROFILE_INC(writecache_flush_reason_write);;
 980                 break;
 981         case SAMBA_READRAW_FLUSH:
 982                 DO_PROFILE_INC(writecache_flush_reason_readraw);
 983                 break;
 984         case SAMBA_OPLOCK_RELEASE_FLUSH:
 985                 DO_PROFILE_INC(writecache_flush_reason_oplock);
 986                 break;
 987         case SAMBA_CLOSE_FLUSH:
 988                 DO_PROFILE_INC(writecache_flush_reason_close);
 989                 break;
 990         case SAMBA_SYNC_FLUSH:
 991                 DO_PROFILE_INC(writecache_flush_reason_sync);
 992                 break;
 993         case SAMBA_SIZECHANGE_FLUSH:
 994                 DO_PROFILE_INC(writecache_flush_reason_sizechange);
 995                 break;
 996         default:
 997                 break;
 998         }
 999
1000         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
1001                 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
1002
1003         if(data_size == wcp->alloc_size) {
1004                 DO_PROFILE_INC(writecache_perfect_writes);
1005         }
1006
1007         ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
1008
1009         /*
1010          * Ensure file size if kept up to date if write extends file.
1011          */
1012
1013         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
1014                 wcp->file_size = wcp->offset + ret;
1015         }
1016
1017         return ret;
1018 }
1019
1020 /*******************************************************************
1021 sync a file
1022 ********************************************************************/
1023
1024 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
1025 {
1026         if (fsp->fh->fd == -1)
1027                 return NT_STATUS_INVALID_HANDLE;
1028
1029         if (lp_strict_sync(SNUM(conn)) &&
1030             (lp_sync_always(SNUM(conn)) || write_through)) {
1031                 int ret = flush_write_cache(fsp, SAMBA_SYNC_FLUSH);
1032                 if (ret == -1) {
1033                         return map_nt_error_from_unix(errno);
1034                 }
1035                 ret = SMB_VFS_FSYNC(fsp);
1036                 if (ret == -1) {
1037                         return map_nt_error_from_unix(errno);
1038                 }
1039         }
1040         return NT_STATUS_OK;
1041 }
1042
1043 /************************************************************
1044  Perform a stat whether a valid fd or not.
1045 ************************************************************/
1046
1047 int fsp_stat(files_struct *fsp)
1048 {
1049         if (fsp->fh->fd == -1) {
1050                 if (fsp->posix_open) {
1051                         return SMB_VFS_LSTAT(fsp->conn, fsp->fsp_name);
1052                 } else {
1053                         return SMB_VFS_STAT(fsp->conn, fsp->fsp_name);
1054                 }
1055         } else {
1056                 return SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st);
1057         }
1058 }