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s3: Rename new parameter "ldap ref follow" to "ldap follow referral".
[Samba/gebeck_regimport.git] / source3 / smbd / fileio.c
blobbd609d3e867798e42163e8d0136f9756b9356cdb
1 /*
2 Unix SMB/Netbios implementation.
3 Version 1.9.
4 read/write to a files_struct
5 Copyright (C) Andrew Tridgell 1992-1998
6 Copyright (C) Jeremy Allison 2000-2002. - write cache.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22 #include "includes.h"
23 #include "smbd/globals.h"
24
25 static bool setup_write_cache(files_struct *, SMB_OFF_T);
26
27 /****************************************************************************
28 Read from write cache if we can.
29 ****************************************************************************/
30
31 static bool read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
32 {
33 write_cache *wcp = fsp->wcp;
34
35 if(!wcp) {
36 return False;
37 }
38
39 if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) {
40 return False;
41 }
42
43 memcpy(data, wcp->data + (pos - wcp->offset), n);
44
45 DO_PROFILE_INC(writecache_read_hits);
46
47 return True;
48 }
49
50 /****************************************************************************
51 Read from a file.
52 ****************************************************************************/
53
54 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
55 {
56 ssize_t ret=0,readret;
57
58 /* you can't read from print files */
59 if (fsp->print_file) {
60 errno = EBADF;
61 return -1;
62 }
63
64 /*
65 * Serve from write cache if we can.
66 */
67
68 if(read_from_write_cache(fsp, data, pos, n)) {
69 fsp->fh->pos = pos + n;
70 fsp->fh->position_information = fsp->fh->pos;
71 return n;
72 }
73
74 flush_write_cache(fsp, READ_FLUSH);
75
76 fsp->fh->pos = pos;
77
78 if (n > 0) {
79 #ifdef DMF_FIX
80 int numretries = 3;
81 tryagain:
82 readret = SMB_VFS_PREAD(fsp,data,n,pos);
83
84 if (readret == -1) {
85 if ((errno == EAGAIN) && numretries) {
86 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
87 (void)sleep(10);
88 --numretries;
89 goto tryagain;
90 }
91 return -1;
92 }
93 #else /* NO DMF fix. */
94 readret = SMB_VFS_PREAD(fsp,data,n,pos);
95
96 if (readret == -1) {
97 return -1;
98 }
99 #endif
100 if (readret > 0) {
101 ret += readret;
102 }
103 }
104
105 DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
106 fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
107
108 fsp->fh->pos += ret;
109 fsp->fh->position_information = fsp->fh->pos;
110
111 return(ret);
112 }
113
114 /****************************************************************************
115 *Really* write to a file.
116 ****************************************************************************/
117
118 static ssize_t real_write_file(struct smb_request *req,
119 files_struct *fsp,
120 const char *data,
121 SMB_OFF_T pos,
122 size_t n)
123 {
124 ssize_t ret;
125
126 if (pos == -1) {
127 ret = vfs_write_data(req, fsp, data, n);
128 } else {
129 fsp->fh->pos = pos;
130 if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
131 if (vfs_fill_sparse(fsp, pos) == -1) {
132 return -1;
133 }
134 }
135 ret = vfs_pwrite_data(req, fsp, data, n, pos);
136 }
137
138 DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
139 fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
140
141 if (ret != -1) {
142 fsp->fh->pos += ret;
143
144 /* Yes - this is correct - writes don't update this. JRA. */
145 /* Found by Samba4 tests. */
146 #if 0
147 fsp->position_information = fsp->pos;
148 #endif
149 }
150
151 return ret;
152 }
153
154 /****************************************************************************
155 File size cache change.
156 Updates size on disk but doesn't flush the cache.
157 ****************************************************************************/
158
159 static int wcp_file_size_change(files_struct *fsp)
160 {
161 int ret;
162 write_cache *wcp = fsp->wcp;
163
164 wcp->file_size = wcp->offset + wcp->data_size;
165 ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
166 if (ret == -1) {
167 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f "
168 "error %s\n", fsp_str_dbg(fsp),
169 (double)wcp->file_size, strerror(errno)));
170 }
171 return ret;
172 }
173
174 static void update_write_time_handler(struct event_context *ctx,
175 struct timed_event *te,
176 struct timeval now,
177 void *private_data)
178 {
179 files_struct *fsp = (files_struct *)private_data;
180
181 /* Remove the timed event handler. */
182 TALLOC_FREE(fsp->update_write_time_event);
183 DEBUG(5, ("Update write time on %s\n", fsp_str_dbg(fsp)));
184
185 /* change the write time if not already changed by someone else */
186 update_write_time(fsp);
187 }
188
189 /*********************************************************
190 Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
191 in the future.
192 *********************************************************/
193
194 void trigger_write_time_update(struct files_struct *fsp)
195 {
196 int delay;
197
198 if (fsp->posix_open) {
199 /* Don't use delayed writes on POSIX files. */
200 return;
201 }
202
203 if (fsp->write_time_forced) {
204 /* No point - "sticky" write times
205 * in effect.
206 */
207 return;
208 }
209
210 if (fsp->update_write_time_triggered) {
211 /*
212 * We only update the write time
213 * on the first write. After that
214 * no other writes affect this.
215 */
216 return;
217 }
218 fsp->update_write_time_triggered = true;
219
220 delay = lp_parm_int(SNUM(fsp->conn),
221 "smbd", "writetimeupdatedelay",
222 WRITE_TIME_UPDATE_USEC_DELAY);
223
224 /* trigger the update 2 seconds later */
225 fsp->update_write_time_on_close = true;
226 fsp->update_write_time_event =
227 event_add_timed(smbd_event_context(), NULL,
228 timeval_current_ofs(0, delay),
229 update_write_time_handler, fsp);
230 }
231
232 void trigger_write_time_update_immediate(struct files_struct *fsp)
233 {
234 if (fsp->posix_open) {
235 /* Don't use delayed writes on POSIX files. */
236 return;
237 }
238
239 if (fsp->write_time_forced) {
240 /*
241 * No point - "sticky" write times
242 * in effect.
243 */
244 return;
245 }
246
247 TALLOC_FREE(fsp->update_write_time_event);
248 DEBUG(5, ("Update write time immediate on %s\n",
249 fsp_str_dbg(fsp)));
250
251 fsp->update_write_time_triggered = true;
252
253 fsp->update_write_time_on_close = false;
254 update_write_time(fsp);
255 }
256
257 /****************************************************************************
258 Write to a file.
259 ****************************************************************************/
260
261 ssize_t write_file(struct smb_request *req,
262 files_struct *fsp,
263 const char *data,
264 SMB_OFF_T pos,
265 size_t n)
266 {
267 write_cache *wcp = fsp->wcp;
268 ssize_t total_written = 0;
269 int write_path = -1;
270
271 if (fsp->print_file) {
272 uint32 jobid;
273
274 if (!rap_to_pjobid(fsp->rap_print_jobid, NULL, &jobid)) {
275 DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
276 (unsigned int)fsp->rap_print_jobid ));
277 errno = EBADF;
278 return -1;
279 }
280
281 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
282 }
283
284 if (!fsp->can_write) {
285 errno = EPERM;
286 return -1;
287 }
288
289 if (!fsp->modified) {
290 fsp->modified = True;
291
292 if (SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st) == 0) {
293 int dosmode;
294 trigger_write_time_update(fsp);
295 dosmode = dos_mode(fsp->conn, fsp->fsp_name);
296 if ((lp_store_dos_attributes(SNUM(fsp->conn)) ||
297 MAP_ARCHIVE(fsp->conn)) &&
298 !IS_DOS_ARCHIVE(dosmode)) {
299 file_set_dosmode(fsp->conn, fsp->fsp_name,
300 dosmode | aARCH, NULL, false);
301 }
302
303 /*
304 * If this is the first write and we have an exclusive oplock then setup
305 * the write cache.
306 */
307
308 if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
309 setup_write_cache(fsp,
310 fsp->fsp_name->st.st_ex_size);
311 wcp = fsp->wcp;
312 }
313 }
314 }
315
316 #ifdef WITH_PROFILE
317 DO_PROFILE_INC(writecache_total_writes);
318 if (!fsp->oplock_type) {
319 DO_PROFILE_INC(writecache_non_oplock_writes);
320 }
321 #endif
322
323 /*
324 * If this file is level II oplocked then we need
325 * to grab the shared memory lock and inform all
326 * other files with a level II lock that they need
327 * to flush their read caches. We keep the lock over
328 * the shared memory area whilst doing this.
329 */
330
331 /* This should actually be improved to span the write. */
332 contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
333 contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
334
335 #ifdef WITH_PROFILE
336 if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
337 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
338 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
339 profile_p->writecache_init_writes,
340 profile_p->writecache_abutted_writes,
341 profile_p->writecache_total_writes,
342 profile_p->writecache_non_oplock_writes,
343 profile_p->writecache_allocated_write_caches,
344 profile_p->writecache_num_write_caches,
345 profile_p->writecache_direct_writes,
346 profile_p->writecache_num_perfect_writes,
347 profile_p->writecache_read_hits ));
348
349 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
350 profile_p->writecache_flushed_writes[SEEK_FLUSH],
351 profile_p->writecache_flushed_writes[READ_FLUSH],
352 profile_p->writecache_flushed_writes[WRITE_FLUSH],
353 profile_p->writecache_flushed_writes[READRAW_FLUSH],
354 profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
355 profile_p->writecache_flushed_writes[CLOSE_FLUSH],
356 profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
357 }
358 #endif
359
360 if (wcp && req->unread_bytes) {
361 /* If we're using receivefile don't
362 * deal with a write cache.
363 */
364 flush_write_cache(fsp, WRITE_FLUSH);
365 delete_write_cache(fsp);
366 wcp = NULL;
367 }
368
369 if(!wcp) {
370 DO_PROFILE_INC(writecache_direct_writes);
371 total_written = real_write_file(req, fsp, data, pos, n);
372 return total_written;
373 }
374
375 DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f "
376 "wcp->data_size=%u\n", fsp_str_dbg(fsp), fsp->fh->fd,
377 (double)pos, (unsigned int)n, (double)wcp->offset,
378 (unsigned int)wcp->data_size));
379
380 fsp->fh->pos = pos + n;
381
382 /*
383 * If we have active cache and it isn't contiguous then we flush.
384 * NOTE: There is a small problem with running out of disk ....
385 */
386
387 if (wcp->data_size) {
388 bool cache_flush_needed = False;
389
390 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
391
392 /* ASCII art.... JRA.
393
394 +--------------+-----
395 | Cached data | Rest of allocated cache buffer....
396 +--------------+-----
397
398 +-------------------+
399 | Data to write |
400 +-------------------+
401
402 */
403
404 /*
405 * Start of write overlaps or abutts the existing data.
406 */
407
408 size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
409
410 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
411
412 /*
413 * Update the current buffer size with the new data.
414 */
415
416 if(pos + data_used > wcp->offset + wcp->data_size) {
417 wcp->data_size = pos + data_used - wcp->offset;
418 }
419
420 /*
421 * Update the file size if changed.
422 */
423
424 if (wcp->offset + wcp->data_size > wcp->file_size) {
425 if (wcp_file_size_change(fsp) == -1) {
426 return -1;
427 }
428 }
429
430 /*
431 * If we used all the data then
432 * return here.
433 */
434
435 if(n == data_used) {
436 return n;
437 } else {
438 cache_flush_needed = True;
439 }
440 /*
441 * Move the start of data forward by the amount used,
442 * cut down the amount left by the same amount.
443 */
444
445 data += data_used;
446 pos += data_used;
447 n -= data_used;
448
449 DO_PROFILE_INC(writecache_abutted_writes);
450 total_written = data_used;
451
452 write_path = 1;
453
454 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
455 (pos + n <= wcp->offset + wcp->alloc_size)) {
456
457 /* ASCII art.... JRA.
458
459 +---------------+
460 | Cache buffer |
461 +---------------+
462
463 +-------------------+
464 | Data to write |
465 +-------------------+
466
467 */
468
469 /*
470 * End of write overlaps the existing data.
471 */
472
473 size_t data_used = pos + n - wcp->offset;
474
475 memcpy(wcp->data, data + n - data_used, data_used);
476
477 /*
478 * Update the current buffer size with the new data.
479 */
480
481 if(pos + n > wcp->offset + wcp->data_size) {
482 wcp->data_size = pos + n - wcp->offset;
483 }
484
485 /*
486 * Update the file size if changed.
487 */
488
489 if (wcp->offset + wcp->data_size > wcp->file_size) {
490 if (wcp_file_size_change(fsp) == -1) {
491 return -1;
492 }
493 }
494
495 /*
496 * We don't need to move the start of data, but we
497 * cut down the amount left by the amount used.
498 */
499
500 n -= data_used;
501
502 /*
503 * We cannot have used all the data here.
504 */
505
506 cache_flush_needed = True;
507
508 DO_PROFILE_INC(writecache_abutted_writes);
509 total_written = data_used;
510
511 write_path = 2;
512
513 } else if ( (pos >= wcp->file_size) &&
514 (wcp->offset + wcp->data_size == wcp->file_size) &&
515 (pos > wcp->offset + wcp->data_size) &&
516 (pos < wcp->offset + wcp->alloc_size) ) {
517
518 /* ASCII art.... JRA.
519
520 End of file ---->|
521
522 +---------------+---------------+
523 | Cached data | Cache buffer |
524 +---------------+---------------+
525
526 +-------------------+
527 | Data to write |
528 +-------------------+
529
530 */
531
532 /*
533 * Non-contiguous write part of which fits within
534 * the cache buffer and is extending the file
535 * and the cache contents reflect the current
536 * data up to the current end of the file.
537 */
538
539 size_t data_used;
540
541 if(pos + n <= wcp->offset + wcp->alloc_size) {
542 data_used = n;
543 } else {
544 data_used = wcp->offset + wcp->alloc_size - pos;
545 }
546
547 /*
548 * Fill in the non-continuous area with zeros.
549 */
550
551 memset(wcp->data + wcp->data_size, '\0',
552 pos - (wcp->offset + wcp->data_size) );
553
554 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
555
556 /*
557 * Update the current buffer size with the new data.
558 */
559
560 if(pos + data_used > wcp->offset + wcp->data_size) {
561 wcp->data_size = pos + data_used - wcp->offset;
562 }
563
564 /*
565 * Update the file size if changed.
566 */
567
568 if (wcp->offset + wcp->data_size > wcp->file_size) {
569 if (wcp_file_size_change(fsp) == -1) {
570 return -1;
571 }
572 }
573
574 /*
575 * If we used all the data then
576 * return here.
577 */
578
579 if(n == data_used) {
580 return n;
581 } else {
582 cache_flush_needed = True;
583 }
584
585 /*
586 * Move the start of data forward by the amount used,
587 * cut down the amount left by the same amount.
588 */
589
590 data += data_used;
591 pos += data_used;
592 n -= data_used;
593
594 DO_PROFILE_INC(writecache_abutted_writes);
595 total_written = data_used;
596
597 write_path = 3;
598
599 } else if ( (pos >= wcp->file_size) &&
600 (n == 1) &&
601 (wcp->file_size == wcp->offset + wcp->data_size) &&
602 (pos < wcp->file_size + wcp->alloc_size)) {
603
604 /*
605
606 End of file ---->|
607
608 +---------------+---------------+
609 | Cached data | Cache buffer |
610 +---------------+---------------+
611
612 |<------- allocated size ---------------->|
613
614 +--------+
615 | 1 Byte |
616 +--------+
617
618 MS-Office seems to do this a lot to determine if there's enough
619 space on the filesystem to write a new file.
620
621 Change to :
622
623 End of file ---->|
624 +-----------------------+--------+
625 | Zeroed Cached data | 1 Byte |
626 +-----------------------+--------+
627 */
628
629 flush_write_cache(fsp, WRITE_FLUSH);
630 wcp->offset = wcp->file_size;
631 wcp->data_size = pos - wcp->file_size + 1;
632 memset(wcp->data, '\0', wcp->data_size);
633 memcpy(wcp->data + wcp->data_size-1, data, 1);
634
635 /*
636 * Update the file size if changed.
637 */
638
639 if (wcp->offset + wcp->data_size > wcp->file_size) {
640 if (wcp_file_size_change(fsp) == -1) {
641 return -1;
642 }
643 }
644
645 return n;
646
647 } else {
648
649 /* ASCII art..... JRA.
650
651 Case 1).
652
653 +---------------+---------------+
654 | Cached data | Cache buffer |
655 +---------------+---------------+
656
657 +-------------------+
658 | Data to write |
659 +-------------------+
660
661 Case 2).
662
663 +---------------+---------------+
664 | Cached data | Cache buffer |
665 +---------------+---------------+
666
667 +-------------------+
668 | Data to write |
669 +-------------------+
670
671 Case 3).
672
673 +---------------+---------------+
674 | Cached data | Cache buffer |
675 +---------------+---------------+
676
677 +-----------------------------------------------------+
678 | Data to write |
679 +-----------------------------------------------------+
680
681 */
682
683 /*
684 * Write is bigger than buffer, or there is no overlap on the
685 * low or high ends.
686 */
687
688 DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
689 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
690
691 /*
692 * If write would fit in the cache, and is larger than
693 * the data already in the cache, flush the cache and
694 * preferentially copy the data new data into it. Otherwise
695 * just write the data directly.
696 */
697
698 if ( n <= wcp->alloc_size && n > wcp->data_size) {
699 cache_flush_needed = True;
700 } else {
701 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
702
703 /*
704 * If the write overlaps the entire cache, then
705 * discard the current contents of the cache.
706 * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
707 */
708
709 if ((pos <= wcp->offset) &&
710 (pos + n >= wcp->offset + wcp->data_size) ) {
711 DEBUG(9,("write_file: discarding overwritten write \
712 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
713 wcp->data_size = 0;
714 }
715
716 DO_PROFILE_INC(writecache_direct_writes);
717 if (ret == -1) {
718 return ret;
719 }
720
721 if (pos + ret > wcp->file_size) {
722 wcp->file_size = pos + ret;
723 }
724
725 return ret;
726 }
727
728 write_path = 4;
729
730 }
731
732 if (cache_flush_needed) {
733 DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
734 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
735 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
736 (double)wcp->offset, (unsigned int)wcp->data_size ));
737
738 flush_write_cache(fsp, WRITE_FLUSH);
739 }
740 }
741
742 /*
743 * If the write request is bigger than the cache
744 * size, write it all out.
745 */
746
747 if (n > wcp->alloc_size ) {
748 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
749 if (ret == -1) {
750 return -1;
751 }
752
753 if (pos + ret > wcp->file_size) {
754 wcp->file_size = pos + n;
755 }
756
757 DO_PROFILE_INC(writecache_direct_writes);
758 return total_written + n;
759 }
760
761 /*
762 * If there's any data left, cache it.
763 */
764
765 if (n) {
766 #ifdef WITH_PROFILE
767 if (wcp->data_size) {
768 DO_PROFILE_INC(writecache_abutted_writes);
769 } else {
770 DO_PROFILE_INC(writecache_init_writes);
771 }
772 #endif
773 memcpy(wcp->data+wcp->data_size, data, n);
774 if (wcp->data_size == 0) {
775 wcp->offset = pos;
776 DO_PROFILE_INC(writecache_num_write_caches);
777 }
778 wcp->data_size += n;
779
780 /*
781 * Update the file size if changed.
782 */
783
784 if (wcp->offset + wcp->data_size > wcp->file_size) {
785 if (wcp_file_size_change(fsp) == -1) {
786 return -1;
787 }
788 }
789 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
790 (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
791
792 total_written += n;
793 return total_written; /* .... that's a write :) */
794 }
795
796 return total_written;
797 }
798
799 /****************************************************************************
800 Delete the write cache structure.
801 ****************************************************************************/
802
803 void delete_write_cache(files_struct *fsp)
804 {
805 write_cache *wcp;
806
807 if(!fsp) {
808 return;
809 }
810
811 if(!(wcp = fsp->wcp)) {
812 return;
813 }
814
815 DO_PROFILE_DEC(writecache_allocated_write_caches);
816 allocated_write_caches--;
817
818 SMB_ASSERT(wcp->data_size == 0);
819
820 SAFE_FREE(wcp->data);
821 SAFE_FREE(fsp->wcp);
822
823 DEBUG(10,("delete_write_cache: File %s deleted write cache\n",
824 fsp_str_dbg(fsp)));
825 }
826
827 /****************************************************************************
828 Setup the write cache structure.
829 ****************************************************************************/
830
831 static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
832 {
833 ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
834 write_cache *wcp;
835
836 if (allocated_write_caches >= MAX_WRITE_CACHES) {
837 return False;
838 }
839
840 if(alloc_size == 0 || fsp->wcp) {
841 return False;
842 }
843
844 if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
845 DEBUG(0,("setup_write_cache: malloc fail.\n"));
846 return False;
847 }
848
849 wcp->file_size = file_size;
850 wcp->offset = 0;
851 wcp->alloc_size = alloc_size;
852 wcp->data_size = 0;
853 if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
854 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
855 (unsigned int)wcp->alloc_size ));
856 SAFE_FREE(wcp);
857 return False;
858 }
859
860 memset(wcp->data, '\0', wcp->alloc_size );
861
862 fsp->wcp = wcp;
863 DO_PROFILE_INC(writecache_allocated_write_caches);
864 allocated_write_caches++;
865
866 DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
867 fsp_str_dbg(fsp), (unsigned long)wcp->alloc_size));
868
869 return True;
870 }
871
872 /****************************************************************************
873 Cope with a size change.
874 ****************************************************************************/
875
876 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
877 {
878 if(fsp->wcp) {
879 /* The cache *must* have been flushed before we do this. */
880 if (fsp->wcp->data_size != 0) {
881 char *msg;
882 if (asprintf(&msg, "set_filelen_write_cache: size change "
883 "on file %s with write cache size = %lu\n",
884 fsp->fsp_name->base_name,
885 (unsigned long)fsp->wcp->data_size) != -1) {
886 smb_panic(msg);
887 } else {
888 smb_panic("set_filelen_write_cache");
889 }
890 }
891 fsp->wcp->file_size = file_size;
892 }
893 }
894
895 /*******************************************************************
896 Flush a write cache struct to disk.
897 ********************************************************************/
898
899 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
900 {
901 write_cache *wcp = fsp->wcp;
902 size_t data_size;
903 ssize_t ret;
904
905 if(!wcp || !wcp->data_size) {
906 return 0;
907 }
908
909 data_size = wcp->data_size;
910 wcp->data_size = 0;
911
912 DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
913
914 DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
915 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
916
917 #ifdef WITH_PROFILE
918 if(data_size == wcp->alloc_size) {
919 DO_PROFILE_INC(writecache_num_perfect_writes);
920 }
921 #endif
922
923 ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
924
925 /*
926 * Ensure file size if kept up to date if write extends file.
927 */
928
929 if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
930 wcp->file_size = wcp->offset + ret;
931 }
932
933 return ret;
934 }
935
936 /*******************************************************************
937 sync a file
938 ********************************************************************/
939
940 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
941 {
942 if (fsp->fh->fd == -1)
943 return NT_STATUS_INVALID_HANDLE;
944
945 if (lp_strict_sync(SNUM(conn)) &&
946 (lp_syncalways(SNUM(conn)) || write_through)) {
947 int ret = flush_write_cache(fsp, SYNC_FLUSH);
948 if (ret == -1) {
949 return map_nt_error_from_unix(errno);
950 }
951 ret = SMB_VFS_FSYNC(fsp);
952 if (ret == -1) {
953 return map_nt_error_from_unix(errno);
954 }
955 }
956 return NT_STATUS_OK;
957 }
958
959 /************************************************************
960 Perform a stat whether a valid fd or not.
961 ************************************************************/
962
963 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
964 {
965 if (fsp->fh->fd == -1) {
966 int ret;
967
968 ret = SMB_VFS_STAT(fsp->conn, fsp->fsp_name);
969 if (ret != -1) {
970 *pst = fsp->fsp_name->st;
971 }
972 return ret;
973 } else {
974 return SMB_VFS_FSTAT(fsp, pst);
975 }
976 }
reg import