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