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         fsp->fh->pos = pos;
 119         if (pos && lp_strict_allocate(SNUM(fsp->conn) &&
 120                         !fsp->is_sparse)) {
 121                 if (vfs_fill_sparse(fsp, pos) == -1) {
 122                         return -1;
 123                 }
 124         }
 125         ret = vfs_pwrite_data(req, fsp, data, n, pos);
 126
 127         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 128                   fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
 129
 130         if (ret != -1) {
 131                 fsp->fh->pos += ret;
 132
 133 /* Yes - this is correct - writes don't update this. JRA. */
 134 /* Found by Samba4 tests. */
 135 #if 0
 136                 fsp->position_information = fsp->pos;
 137 #endif
 138         }
 139
 140         return ret;
 141 }
 142
 143 /****************************************************************************
 144  File size cache change.
 145  Updates size on disk but doesn't flush the cache.
 146 ****************************************************************************/
 147
 148 static int wcp_file_size_change(files_struct *fsp)
 149 {
 150         int ret;
 151         struct write_cache *wcp = fsp->wcp;
 152
 153         wcp->file_size = wcp->offset + wcp->data_size;
 154         ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
 155         if (ret == -1) {
 156                 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f "
 157                          "error %s\n", fsp_str_dbg(fsp),
 158                          (double)wcp->file_size, strerror(errno)));
 159         }
 160         return ret;
 161 }
 162
 163 void fsp_flush_write_time_update(struct files_struct *fsp)
 164 {
 165         /*
 166          * Note this won't expect any impersonation!
 167          * So don't call any SMB_VFS operations here!
 168          */
 169
 170         DEBUG(5, ("Update write time on %s\n", fsp_str_dbg(fsp)));
 171
 172         /* change the write time in the open file db. */
 173         (void)set_write_time(fsp->file_id, timespec_current());
 174
 175         /* And notify. */
 176         notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
 177                      FILE_NOTIFY_CHANGE_LAST_WRITE, fsp->fsp_name->base_name);
 178
 179         /* Remove the timed event handler. */
 180         TALLOC_FREE(fsp->update_write_time_event);
 181 }
 182
 183 static void update_write_time_handler(struct tevent_context *ctx,
 184                                       struct tevent_timer *te,
 185                                       struct timeval now,
 186                                       void *private_data)
 187 {
 188         files_struct *fsp = (files_struct *)private_data;
 189         fsp_flush_write_time_update(fsp);
 190 }
 191
 192 /*********************************************************
 193  Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
 194  in the future.
 195 *********************************************************/
 196
 197 void trigger_write_time_update(struct files_struct *fsp)
 198 {
 199         int delay;
 200
 201         if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
 202                 /* Don't use delayed writes on POSIX files. */
 203                 return;
 204         }
 205
 206         if (fsp->write_time_forced) {
 207                 /* No point - "sticky" write times
 208                  * in effect.
 209                  */
 210                 return;
 211         }
 212
 213         /* We need to remember someone did a write
 214          * and update to current time on close. */
 215
 216         fsp->update_write_time_on_close = true;
 217
 218         if (fsp->update_write_time_triggered) {
 219                 /*
 220                  * We only update the write time after 2 seconds
 221                  * on the first normal write. After that
 222                  * no other writes affect this until close.
 223                  */
 224                 return;
 225         }
 226         fsp->update_write_time_triggered = true;
 227
 228         delay = lp_parm_int(SNUM(fsp->conn),
 229                             "smbd", "writetimeupdatedelay",
 230                             WRITE_TIME_UPDATE_USEC_DELAY);
 231
 232         DEBUG(5, ("Update write time %d usec later on %s\n",
 233                   delay, fsp_str_dbg(fsp)));
 234
 235         /* trigger the update 2 seconds later */
 236         fsp->update_write_time_event =
 237                 tevent_add_timer(fsp->conn->sconn->ev_ctx, NULL,
 238                                  timeval_current_ofs_usec(delay),
 239                                  update_write_time_handler, fsp);
 240 }
 241
 242 void trigger_write_time_update_immediate(struct files_struct *fsp)
 243 {
 244         struct smb_file_time ft;
 245
 246         if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
 247                 /* Don't use delayed writes on POSIX files. */
 248                 return;
 249         }
 250
 251         if (fsp->write_time_forced) {
 252                 /*
 253                  * No point - "sticky" write times
 254                  * in effect.
 255                  */
 256                 return;
 257         }
 258
 259         TALLOC_FREE(fsp->update_write_time_event);
 260         DEBUG(5, ("Update write time immediate on %s\n",
 261                   fsp_str_dbg(fsp)));
 262
 263         /* After an immediate update, reset the trigger. */
 264         fsp->update_write_time_triggered = true;
 265         fsp->update_write_time_on_close = false;
 266
 267         ft = (struct smb_file_time) { .mtime = timespec_current() };
 268
 269         /* Update the time in the open file db. */
 270         (void)set_write_time(fsp->file_id, ft.mtime);
 271
 272         /* Now set on disk - takes care of notify. */
 273         (void)smb_set_file_time(fsp->conn, fsp, fsp->fsp_name, &ft, false);
 274 }
 275
 276 void mark_file_modified(files_struct *fsp)
 277 {
 278         int dosmode;
 279
 280         if (fsp->modified) {
 281                 return;
 282         }
 283
 284         fsp->modified = true;
 285
 286         if (SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st) != 0) {
 287                 return;
 288         }
 289         trigger_write_time_update(fsp);
 290
 291         if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
 292                 return;
 293         }
 294         if (!(lp_store_dos_attributes(SNUM(fsp->conn)) ||
 295               MAP_ARCHIVE(fsp->conn))) {
 296                 return;
 297         }
 298
 299         dosmode = dos_mode(fsp->conn, fsp->fsp_name);
 300         if (IS_DOS_ARCHIVE(dosmode)) {
 301                 return;
 302         }
 303         file_set_dosmode(fsp->conn, fsp->fsp_name,
 304                          dosmode | FILE_ATTRIBUTE_ARCHIVE, NULL, false);
 305 }
 306
 307 /****************************************************************************
 308  Write to a file.
 309 ****************************************************************************/
 310
 311 ssize_t write_file(struct smb_request *req,
 312                         files_struct *fsp,
 313                         const char *data,
 314                         off_t pos,
 315                         size_t n)
 316 {
 317         struct write_cache *wcp = fsp->wcp;
 318         ssize_t total_written = 0;
 319         int write_path = -1;
 320
 321         if (fsp->print_file) {
 322                 uint32_t t;
 323                 int ret;
 324
 325                 ret = print_spool_write(fsp, data, n, pos, &t);
 326                 if (ret) {
 327                         errno = ret;
 328                         return -1;
 329                 }
 330                 return t;
 331         }
 332
 333         if (!fsp->can_write) {
 334                 errno = EPERM;
 335                 return -1;
 336         }
 337
 338         /*
 339          * If this is the first write and we have an exclusive oplock
 340          * then setup the write cache.
 341          */
 342
 343         if (!fsp->modified &&
 344             EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) &&
 345             (wcp == NULL)) {
 346                 /*
 347                  * Note: no write cache with leases!
 348                  * as the handles would have to share the write cache
 349                  * that's possible but an improvement for another day...
 350                  */
 351                 setup_write_cache(fsp, fsp->fsp_name->st.st_ex_size);
 352                 wcp = fsp->wcp;
 353         }
 354
 355         mark_file_modified(fsp);
 356
 357         DO_PROFILE_INC(writecache_total_writes);
 358         if (!fsp->oplock_type) {
 359                 DO_PROFILE_INC(writecache_non_oplock_writes);
 360         }
 361
 362         /*
 363          * If this file is level II oplocked then we need
 364          * to grab the shared memory lock and inform all
 365          * other files with a level II lock that they need
 366          * to flush their read caches. We keep the lock over
 367          * the shared memory area whilst doing this.
 368          */
 369
 370         /* This should actually be improved to span the write. */
 371         contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
 372         contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
 373
 374         if (wcp && req->unread_bytes) {
 375                 /* If we're using receivefile don't
 376                  * deal with a write cache.
 377                  */
 378                 flush_write_cache(fsp, SAMBA_WRITE_FLUSH);
 379                 delete_write_cache(fsp);
 380                 wcp = NULL;
 381         }
 382
 383         if(!wcp) {
 384                 DO_PROFILE_INC(writecache_direct_writes);
 385                 total_written = real_write_file(req, fsp, data, pos, n);
 386                 return total_written;
 387         }
 388
 389         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f "
 390                  "wcp->data_size=%u\n", fsp_str_dbg(fsp), fsp->fh->fd,
 391                  (double)pos, (unsigned int)n, (double)wcp->offset,
 392                  (unsigned int)wcp->data_size));
 393
 394         fsp->fh->pos = pos + n;
 395
 396         if ((n == 1) && (data[0] == '\0') && (pos > wcp->file_size)) {
 397                 int ret;
 398
 399                 /*
 400                  * This is a 1-byte write of a 0 beyond the EOF and
 401                  * thus implicitly also beyond the current active
 402                  * write cache, the typical file-extending (and
 403                  * allocating, but we're using the write cache here)
 404                  * write done by Windows. We just have to ftruncate
 405                  * the file and rely on posix semantics to return
 406                  * zeros for non-written file data that is within the
 407                  * file length.
 408                  *
 409                  * We can not use wcp_file_size_change here because we
 410                  * might have an existing write cache, and
 411                  * wcp_file_size_change assumes a change to just the
 412                  * end of the current write cache.
 413                  */
 414
 415                 wcp->file_size = pos + 1;
 416                 ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
 417                 if (ret == -1) {
 418                         DEBUG(0, ("wcp_file_size_change (%s): ftruncate of "
 419                                   "size %.0f error %s\n", fsp_str_dbg(fsp),
 420                                   (double)wcp->file_size, strerror(errno)));
 421                         return -1;
 422                 }
 423                 return 1;
 424         }
 425
 426
 427         /*
 428          * If we have active cache and it isn't contiguous then we flush.
 429          * NOTE: There is a small problem with running out of disk ....
 430          */
 431
 432         if (wcp->data_size) {
 433                 bool cache_flush_needed = False;
 434
 435                 if ((pos >= wcp->offset) &&
 436                     (pos <= wcp->offset + wcp->data_size)) {
 437
 438                         /* ASCII art.... JRA.
 439
 440       +--------------+-----
 441       | Cached data  | Rest of allocated cache buffer....
 442       +--------------+-----
 443
 444             +-------------------+
 445             | Data to write     |
 446             +-------------------+
 447
 448                         */
 449
 450                         /*
 451                          * Start of write overlaps or abutts the existing data.
 452                          */
 453
 454                         size_t data_used;
 455
 456                         data_used = MIN((wcp->alloc_size - (pos - wcp->offset)),
 457                                         n);
 458
 459                         memcpy(wcp->data + (pos - wcp->offset), data,
 460                                data_used);
 461
 462                         /*
 463                          * Update the current buffer size with the new data.
 464                          */
 465
 466                         if(pos + data_used > wcp->offset + wcp->data_size) {
 467                                 wcp->data_size = pos + data_used - wcp->offset;
 468                         }
 469
 470                         /*
 471                          * Update the file size if changed.
 472                          */
 473
 474                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 475                                 if (wcp_file_size_change(fsp) == -1) {
 476                                         return -1;
 477                                 }
 478                         }
 479
 480                         /*
 481                          * If we used all the data then
 482                          * return here.
 483                          */
 484
 485                         if(n == data_used) {
 486                                 return n;
 487                         } else {
 488                                 cache_flush_needed = True;
 489                         }
 490                         /*
 491                          * Move the start of data forward by the amount used,
 492                          * cut down the amount left by the same amount.
 493                          */
 494
 495                         data += data_used;
 496                         pos += data_used;
 497                         n -= data_used;
 498
 499                         DO_PROFILE_INC(writecache_abutted_writes);
 500                         total_written = data_used;
 501
 502                         write_path = 1;
 503
 504                 } else if ((pos < wcp->offset) &&
 505                            (pos + n > wcp->offset) &&
 506                            (pos + n <= wcp->offset + wcp->alloc_size)) {
 507
 508                         /* ASCII art.... JRA.
 509
 510                         +---------------+
 511                         | Cache buffer  |
 512                         +---------------+
 513
 514             +-------------------+
 515             | Data to write     |
 516             +-------------------+
 517
 518                         */
 519
 520                         /*
 521                          * End of write overlaps the existing data.
 522                          */
 523
 524                         size_t data_used = pos + n - wcp->offset;
 525
 526                         memcpy(wcp->data, data + n - data_used, data_used);
 527
 528                         /*
 529                          * Update the current buffer size with the new data.
 530                          */
 531
 532                         if(pos + n > wcp->offset + wcp->data_size) {
 533                                 wcp->data_size = pos + n - wcp->offset;
 534                         }
 535
 536                         /*
 537                          * Update the file size if changed.
 538                          */
 539
 540                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 541                                 if (wcp_file_size_change(fsp) == -1) {
 542                                         return -1;
 543                                 }
 544                         }
 545
 546                         /*
 547                          * We don't need to move the start of data, but we
 548                          * cut down the amount left by the amount used.
 549                          */
 550
 551                         n -= data_used;
 552
 553                         /*
 554                          * We cannot have used all the data here.
 555                          */
 556
 557                         cache_flush_needed = True;
 558
 559                         DO_PROFILE_INC(writecache_abutted_writes);
 560                         total_written = data_used;
 561
 562                         write_path = 2;
 563
 564                 } else if ((pos >= wcp->file_size) &&
 565                            (wcp->offset + wcp->data_size == wcp->file_size) &&
 566                            (pos > wcp->offset + wcp->data_size) &&
 567                            (pos < wcp->offset + wcp->alloc_size) ) {
 568
 569                         /* ASCII art.... JRA.
 570
 571                        End of file ---->|
 572
 573                         +---------------+---------------+
 574                         | Cached data   | Cache buffer  |
 575                         +---------------+---------------+
 576
 577                                               +-------------------+
 578                                               | Data to write     |
 579                                               +-------------------+
 580
 581                         */
 582
 583                         /*
 584                          * Non-contiguous write part of which fits within
 585                          * the cache buffer and is extending the file
 586                          * and the cache contents reflect the current
 587                          * data up to the current end of the file.
 588                          */
 589
 590                         size_t data_used;
 591
 592                         if(pos + n <= wcp->offset + wcp->alloc_size) {
 593                                 data_used = n;
 594                         } else {
 595                                 data_used = wcp->offset+wcp->alloc_size-pos;
 596                         }
 597
 598                         /*
 599                          * Fill in the non-continuous area with zeros.
 600                          */
 601
 602                         memset(wcp->data + wcp->data_size, '\0',
 603                                 pos - (wcp->offset + wcp->data_size) );
 604
 605                         memcpy(wcp->data + (pos - wcp->offset), data,
 606                                data_used);
 607
 608                         /*
 609                          * Update the current buffer size with the new data.
 610                          */
 611
 612                         if(pos + data_used > wcp->offset + wcp->data_size) {
 613                                 wcp->data_size = pos + data_used - wcp->offset;
 614                         }
 615
 616                         /*
 617                          * Update the file size if changed.
 618                          */
 619
 620                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 621                                 if (wcp_file_size_change(fsp) == -1) {
 622                                         return -1;
 623                                 }
 624                         }
 625
 626                         /*
 627                          * If we used all the data then
 628                          * return here.
 629                          */
 630
 631                         if(n == data_used) {
 632                                 return n;
 633                         } else {
 634                                 cache_flush_needed = True;
 635                         }
 636
 637                         /*
 638                          * Move the start of data forward by the amount used,
 639                          * cut down the amount left by the same amount.
 640                          */
 641
 642                         data += data_used;
 643                         pos += data_used;
 644                         n -= data_used;
 645
 646                         DO_PROFILE_INC(writecache_abutted_writes);
 647                         total_written = data_used;
 648
 649                         write_path = 3;
 650
 651                 } else if ( (pos >= wcp->file_size) &&
 652                             (n == 1) &&
 653                             (wcp->file_size == wcp->offset + wcp->data_size) &&
 654                             (pos < wcp->file_size + wcp->alloc_size)) {
 655
 656                         /*
 657
 658                 End of file ---->|
 659
 660                  +---------------+---------------+
 661                  | Cached data   | Cache buffer  |
 662                  +---------------+---------------+
 663
 664                                  |<------- allocated size ---------------->|
 665
 666                                                          +--------+
 667                                                          | 1 Byte |
 668                                                          +--------+
 669
 670                         MS-Office seems to do this a lot to determine if
 671                         there's enough space on the filesystem to write a new
 672                         file.
 673
 674                         Change to :
 675
 676                 End of file ---->|
 677                                  +-----------------------+--------+
 678                                  | Zeroed Cached data    | 1 Byte |
 679                                  +-----------------------+--------+
 680                         */
 681
 682                         flush_write_cache(fsp, SAMBA_WRITE_FLUSH);
 683                         wcp->offset = wcp->file_size;
 684                         wcp->data_size = pos - wcp->file_size + 1;
 685                         memset(wcp->data, '\0', wcp->data_size);
 686                         memcpy(wcp->data + wcp->data_size-1, data, 1);
 687
 688                         /*
 689                          * Update the file size if changed.
 690                          */
 691
 692                         if (wcp->offset + wcp->data_size > wcp->file_size) {
 693                                 if (wcp_file_size_change(fsp) == -1) {
 694                                         return -1;
 695                                 }
 696                         }
 697
 698                         return n;
 699
 700                 } else {
 701
 702                         /* ASCII art..... JRA.
 703
 704    Case 1).
 705
 706                         +---------------+---------------+
 707                         | Cached data   | Cache buffer  |
 708                         +---------------+---------------+
 709
 710                                                               +---------------+
 711                                                               | Data to write |
 712                                                               +---------------+
 713
 714    Case 2).
 715
 716                            +---------------+---------------+
 717                            | Cached data   | Cache buffer  |
 718                            +---------------+---------------+
 719
 720    +-------------------+
 721    | Data to write     |
 722    +-------------------+
 723
 724     Case 3).
 725
 726                            +---------------+---------------+
 727                            | Cached data   | Cache buffer  |
 728                            +---------------+---------------+
 729
 730                   +-----------------------------------------------------+
 731                   | Data to write                                       |
 732                   +-----------------------------------------------------+
 733
 734                   */
 735
 736                         /*
 737                          * Write is bigger than buffer, or there is no
 738                          * overlap on the low or high ends.
 739                          */
 740
 741                         DEBUG(9,("write_file: non cacheable write : fd = %d, "
 742                                  "pos = %.0f, len = %u, "
 743                                  "current cache pos = %.0f len = %u\n",
 744                                  fsp->fh->fd, (double)pos, (unsigned int)n,
 745                                  (double)wcp->offset,
 746                                  (unsigned int)wcp->data_size ));
 747
 748                         /*
 749                          * If write would fit in the cache, and is
 750                          * larger than the data already in the cache,
 751                          * flush the cache and preferentially copy the
 752                          * data new data into it. Otherwise just write
 753                          * the data directly.
 754                          */
 755
 756                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
 757                                 cache_flush_needed = True;
 758                         } else {
 759                                 ssize_t ret = real_write_file(NULL, fsp, data,
 760                                                               pos, n);
 761
 762                                 /*
 763                                  * If the write overlaps the entire
 764                                  * cache, then discard the current
 765                                  * contents of the cache.  Fix from
 766                                  * Rasmus Borup Hansen rbh@math.ku.dk.
 767                                  */
 768
 769                                 if ((pos <= wcp->offset) &&
 770                                     (pos + n >= wcp->offset+wcp->data_size)) {
 771                                         DEBUG(9,("write_file: discarding "
 772                                                  "overwritten write cache: "
 773                                                  "fd = %d, off=%.0f, "
 774                                                  "size=%u\n", fsp->fh->fd,
 775                                                  (double)wcp->offset,
 776                                                  (unsigned)wcp->data_size));
 777                                         wcp->data_size = 0;
 778                                 }
 779
 780                                 DO_PROFILE_INC(writecache_direct_writes);
 781                                 if (ret == -1) {
 782                                         return ret;
 783                                 }
 784
 785                                 if (pos + ret > wcp->file_size) {
 786                                         wcp->file_size = pos + ret;
 787                                 }
 788
 789                                 return ret;
 790                         }
 791
 792                         write_path = 4;
 793
 794                 }
 795
 796                 if (cache_flush_needed) {
 797                         DEBUG(3, ("SAMBA_WRITE_FLUSH:%d: due to noncontinuous "
 798                                   "write: fd = %d, size = %.0f, pos = %.0f, "
 799                                   "n = %u, wcp->offset=%.0f, "
 800                                   "wcp->data_size=%u\n",
 801                                   write_path, fsp->fh->fd,
 802                                   (double)wcp->file_size, (double)pos,
 803                                   (unsigned int)n, (double)wcp->offset,
 804                                   (unsigned int)wcp->data_size ));
 805
 806                         flush_write_cache(fsp, SAMBA_WRITE_FLUSH);
 807                 }
 808         }
 809
 810         /*
 811          * If the write request is bigger than the cache
 812          * size, write it all out.
 813          */
 814
 815         if (n > wcp->alloc_size ) {
 816                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
 817                 if (ret == -1) {
 818                         return -1;
 819                 }
 820
 821                 if (pos + ret > wcp->file_size) {
 822                         wcp->file_size = pos + n;
 823                 }
 824
 825                 DO_PROFILE_INC(writecache_direct_writes);
 826                 return total_written + n;
 827         }
 828
 829         /*
 830          * If there's any data left, cache it.
 831          */
 832
 833         if (n) {
 834                 DO_PROFILE_INC(writecache_cached_writes);
 835                 if (wcp->data_size) {
 836                         DO_PROFILE_INC(writecache_abutted_writes);
 837                 } else {
 838                         DO_PROFILE_INC(writecache_init_writes);
 839                 }
 840
 841                 if ((wcp->data_size == 0)
 842                     && (pos > wcp->file_size)
 843                     && (pos + n <= wcp->file_size + wcp->alloc_size)) {
 844                         /*
 845                          * This is a write completely beyond the
 846                          * current EOF, but within reach of the write
 847                          * cache. We expect fill-up writes pretty
 848                          * soon, so it does not make sense to start
 849                          * the write cache at the current
 850                          * offset. These fill-up writes would trigger
 851                          * separate pwrites or even unnecessary cache
 852                          * flushes because they overlap if this is a
 853                          * one-byte allocating write.
 854                          */
 855                         wcp->offset = wcp->file_size;
 856                         wcp->data_size = pos - wcp->file_size;
 857                         memset(wcp->data, 0, wcp->data_size);
 858                 }
 859
 860                 memcpy(wcp->data+wcp->data_size, data, n);
 861                 if (wcp->data_size == 0) {
 862                         wcp->offset = pos;
 863                 }
 864                 wcp->data_size += n;
 865
 866                 /*
 867                  * Update the file size if changed.
 868                  */
 869
 870                 if (wcp->offset + wcp->data_size > wcp->file_size) {
 871                         if (wcp_file_size_change(fsp) == -1) {
 872                                 return -1;
 873                         }
 874                 }
 875                 DEBUG(9, ("wcp->offset = %.0f wcp->data_size = %u cache "
 876                           "return %u\n",
 877                           (double)wcp->offset, (unsigned int)wcp->data_size,
 878                           (unsigned int)n));
 879
 880                 total_written += n;
 881                 return total_written; /* .... that's a write :) */
 882         }
 883
 884         return total_written;
 885 }
 886
 887 /****************************************************************************
 888  Delete the write cache structure.
 889 ****************************************************************************/
 890
 891 void delete_write_cache(files_struct *fsp)
 892 {
 893         struct write_cache *wcp;
 894
 895         if(!fsp) {
 896                 return;
 897         }
 898
 899         if(!(wcp = fsp->wcp)) {
 900                 return;
 901         }
 902
 903         DO_PROFILE_INC(writecache_deallocations);
 904         allocated_write_caches--;
 905
 906         SMB_ASSERT(wcp->data_size == 0);
 907
 908         SAFE_FREE(wcp->data);
 909         SAFE_FREE(fsp->wcp);
 910
 911         DEBUG(10,("delete_write_cache: File %s deleted write cache\n",
 912                   fsp_str_dbg(fsp)));
 913 }
 914
 915 /****************************************************************************
 916  Setup the write cache structure.
 917 ****************************************************************************/
 918
 919 static bool setup_write_cache(files_struct *fsp, off_t file_size)
 920 {
 921         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
 922         struct write_cache *wcp;
 923
 924         if (allocated_write_caches >= MAX_WRITE_CACHES) {
 925                 return False;
 926         }
 927
 928         if(alloc_size == 0 || fsp->wcp) {
 929                 return False;
 930         }
 931
 932         if((wcp = SMB_MALLOC_P(struct write_cache)) == NULL) {
 933                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
 934                 return False;
 935         }
 936
 937         wcp->file_size = file_size;
 938         wcp->offset = 0;
 939         wcp->alloc_size = alloc_size;
 940         wcp->data_size = 0;
 941         if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
 942                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
 943                         (unsigned int)wcp->alloc_size ));
 944                 SAFE_FREE(wcp);
 945                 return False;
 946         }
 947
 948         memset(wcp->data, '\0', wcp->alloc_size );
 949
 950         fsp->wcp = wcp;
 951         DO_PROFILE_INC(writecache_allocations);
 952         allocated_write_caches++;
 953
 954         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
 955                   fsp_str_dbg(fsp), (unsigned long)wcp->alloc_size));
 956
 957         return True;
 958 }
 959
 960 /****************************************************************************
 961  Cope with a size change.
 962 ****************************************************************************/
 963
 964 void set_filelen_write_cache(files_struct *fsp, off_t file_size)
 965 {
 966         if(fsp->wcp) {
 967                 /* The cache *must* have been flushed before we do this. */
 968                 if (fsp->wcp->data_size != 0) {
 969                         char *msg;
 970                         if (asprintf(&msg, "set_filelen_write_cache: size change "
 971                                  "on file %s with write cache size = %lu\n",
 972                                  fsp->fsp_name->base_name,
 973                                  (unsigned long)fsp->wcp->data_size) != -1) {
 974                                 smb_panic(msg);
 975                         } else {
 976                                 smb_panic("set_filelen_write_cache");
 977                         }
 978                 }
 979                 fsp->wcp->file_size = file_size;
 980         }
 981 }
 982
 983 /*******************************************************************
 984  Flush a write cache struct to disk.
 985 ********************************************************************/
 986
 987 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
 988 {
 989         struct write_cache *wcp = fsp->wcp;
 990         size_t data_size;
 991         ssize_t ret;
 992
 993         if(!wcp || !wcp->data_size) {
 994                 return 0;
 995         }
 996
 997         data_size = wcp->data_size;
 998         wcp->data_size = 0;
 999
1000         switch (reason) {
1001         case SAMBA_SEEK_FLUSH:
1002                 DO_PROFILE_INC(writecache_flush_reason_seek);
1003                 break;
1004         case SAMBA_READ_FLUSH:
1005                 DO_PROFILE_INC(writecache_flush_reason_read);
1006                 break;
1007         case SAMBA_WRITE_FLUSH:
1008                 DO_PROFILE_INC(writecache_flush_reason_write);;
1009                 break;
1010         case SAMBA_READRAW_FLUSH:
1011                 DO_PROFILE_INC(writecache_flush_reason_readraw);
1012                 break;
1013         case SAMBA_OPLOCK_RELEASE_FLUSH:
1014                 DO_PROFILE_INC(writecache_flush_reason_oplock);
1015                 break;
1016         case SAMBA_CLOSE_FLUSH:
1017                 DO_PROFILE_INC(writecache_flush_reason_close);
1018                 break;
1019         case SAMBA_SYNC_FLUSH:
1020                 DO_PROFILE_INC(writecache_flush_reason_sync);
1021                 break;
1022         case SAMBA_SIZECHANGE_FLUSH:
1023                 DO_PROFILE_INC(writecache_flush_reason_sizechange);
1024                 break;
1025         default:
1026                 break;
1027         }
1028
1029         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
1030                 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
1031
1032         if(data_size == wcp->alloc_size) {
1033                 DO_PROFILE_INC(writecache_perfect_writes);
1034         }
1035
1036         ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
1037
1038         /*
1039          * Ensure file size if kept up to date if write extends file.
1040          */
1041
1042         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
1043                 wcp->file_size = wcp->offset + ret;
1044         }
1045
1046         return ret;
1047 }
1048
1049 /*******************************************************************
1050 sync a file
1051 ********************************************************************/
1052
1053 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
1054 {
1055         if (fsp->fh->fd == -1)
1056                 return NT_STATUS_INVALID_HANDLE;
1057
1058         if (lp_strict_sync(SNUM(conn)) &&
1059             (lp_sync_always(SNUM(conn)) || write_through)) {
1060                 int ret = flush_write_cache(fsp, SAMBA_SYNC_FLUSH);
1061                 if (ret == -1) {
1062                         return map_nt_error_from_unix(errno);
1063                 }
1064                 ret = smb_vfs_fsync_sync(fsp);
1065                 if (ret == -1) {
1066                         return map_nt_error_from_unix(errno);
1067                 }
1068         }
1069         return NT_STATUS_OK;
1070 }
1071
1072 /************************************************************
1073  Perform a stat whether a valid fd or not.
1074 ************************************************************/
1075
1076 int fsp_stat(files_struct *fsp)
1077 {
1078         if (fsp->fh->fd == -1) {
1079                 if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
1080                         return SMB_VFS_LSTAT(fsp->conn, fsp->fsp_name);
1081                 } else {
1082                         return SMB_VFS_STAT(fsp->conn, fsp->fsp_name);
1083                 }
1084         } else {
1085                 return SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st);
1086         }
1087 }