source: branches/samba-3.2.x/source/smbd/fileio.c

Last change on this file was 204, checked in by Herwig Bauernfeind, 16 years ago

Update 3.2 branch to 3.2.4
File size: 25.0 KB
RevLine 
[204]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
24static bool setup_write_cache(files_struct *, SMB_OFF_T);
25
26/****************************************************************************
27 Read from write cache if we can.
28****************************************************************************/
29
30static bool read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
31{
32 write_cache *wcp = fsp->wcp;
33
34 if(!wcp) {
35 return False;
36 }
37
38 if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) {
39 return False;
40 }
41
42 memcpy(data, wcp->data + (pos - wcp->offset), n);
43
44 DO_PROFILE_INC(writecache_read_hits);
45
46 return True;
47}
48
49/****************************************************************************
50 Read from a file.
51****************************************************************************/
52
53ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
54{
55 ssize_t ret=0,readret;
56
57 /* you can't read from print files */
58 if (fsp->print_file) {
59 return -1;
60 }
61
62 /*
63 * Serve from write cache if we can.
64 */
65
66 if(read_from_write_cache(fsp, data, pos, n)) {
67 fsp->fh->pos = pos + n;
68 fsp->fh->position_information = fsp->fh->pos;
69 return n;
70 }
71
72 flush_write_cache(fsp, READ_FLUSH);
73
74 fsp->fh->pos = pos;
75
76 if (n > 0) {
77#ifdef DMF_FIX
78 int numretries = 3;
79tryagain:
80 readret = SMB_VFS_PREAD(fsp,data,n,pos);
81
82 if (readret == -1) {
83 if ((errno == EAGAIN) && numretries) {
84 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
85 (void)sleep(10);
86 --numretries;
87 goto tryagain;
88 }
89 return -1;
90 }
91#else /* NO DMF fix. */
92 readret = SMB_VFS_PREAD(fsp,data,n,pos);
93
94 if (readret == -1) {
95 return -1;
96 }
97#endif
98 if (readret > 0) {
99 ret += readret;
100 }
101 }
102
103 DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
104 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
105
106 fsp->fh->pos += ret;
107 fsp->fh->position_information = fsp->fh->pos;
108
109 return(ret);
110}
111
112/* how many write cache buffers have been allocated */
113static unsigned int allocated_write_caches;
114
115/****************************************************************************
116 *Really* write to a file.
117****************************************************************************/
118
119static ssize_t real_write_file(struct smb_request *req,
120 files_struct *fsp,
121 const char *data,
122 SMB_OFF_T pos,
123 size_t n)
124{
125 ssize_t ret;
126
127 if (pos == -1) {
128 ret = vfs_write_data(req, fsp, data, n);
129 } else {
130 fsp->fh->pos = pos;
131 if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
132 if (vfs_fill_sparse(fsp, pos) == -1) {
133 return -1;
134 }
135 }
136 ret = vfs_pwrite_data(req, fsp, data, n, pos);
137 }
138
139 DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
140 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
141
142 if (ret != -1) {
143 fsp->fh->pos += ret;
144
145/* Yes - this is correct - writes don't update this. JRA. */
146/* Found by Samba4 tests. */
147#if 0
148 fsp->position_information = fsp->pos;
149#endif
150 }
151
152 return ret;
153}
154
155/****************************************************************************
156 File size cache change.
157 Updates size on disk but doesn't flush the cache.
158****************************************************************************/
159
160static int wcp_file_size_change(files_struct *fsp)
161{
162 int ret;
163 write_cache *wcp = fsp->wcp;
164
165 wcp->file_size = wcp->offset + wcp->data_size;
166 ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
167 if (ret == -1) {
168 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f error %s\n",
169 fsp->fsp_name, (double)wcp->file_size, strerror(errno) ));
170 }
171 return ret;
172}
173
174static void update_write_time_handler(struct event_context *ctx,
175 struct timed_event *te,
176 const 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->fsp_name));
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
194void trigger_write_time_update(struct files_struct *fsp)
195{
196 int delay;
197
198 if (fsp->write_time_forced) {
199 /* No point - "sticky" write times
200 * in effect.
201 */
202 return;
203 }
204
205 if (fsp->update_write_time_triggered) {
206 /*
207 * We only update the write time
208 * on the first write. After that
209 * no other writes affect this.
210 */
211 return;
212 }
213 fsp->update_write_time_triggered = true;
214
215 delay = lp_parm_int(SNUM(fsp->conn),
216 "smbd", "writetimeupdatedelay",
217 WRITE_TIME_UPDATE_USEC_DELAY);
218
219 /* trigger the update 2 seconds later */
220 fsp->update_write_time_on_close = true;
221 fsp->update_write_time_event =
222 event_add_timed(smbd_event_context(), NULL,
223 timeval_current_ofs(0, delay),
224 "update_write_time_handler",
225 update_write_time_handler, fsp);
226}
227
228void trigger_write_time_update_immediate(struct files_struct *fsp)
229{
230 if (fsp->write_time_forced) {
231 /*
232 * No point - "sticky" write times
233 * in effect.
234 */
235 return;
236 }
237
238 TALLOC_FREE(fsp->update_write_time_event);
239 DEBUG(5, ("Update write time immediate on %s\n", fsp->fsp_name));
240
241 fsp->update_write_time_triggered = true;
242
243 fsp->update_write_time_on_close = false;
244 update_write_time(fsp);
245}
246
247/****************************************************************************
248 Write to a file.
249****************************************************************************/
250
251ssize_t write_file(struct smb_request *req,
252 files_struct *fsp,
253 const char *data,
254 SMB_OFF_T pos,
255 size_t n)
256{
257 write_cache *wcp = fsp->wcp;
258 ssize_t total_written = 0;
259 int write_path = -1;
260
261 if (fsp->print_file) {
262 fstring sharename;
263 uint32 jobid;
264
265 if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
266 DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
267 (unsigned int)fsp->rap_print_jobid ));
268 errno = EBADF;
269 return -1;
270 }
271
272 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
273 }
274
275 if (!fsp->can_write) {
276 errno = EPERM;
277 return -1;
278 }
279
280 if (!fsp->modified) {
281 SMB_STRUCT_STAT st;
282 fsp->modified = True;
283
284 if (SMB_VFS_FSTAT(fsp, &st) == 0) {
285 int dosmode;
286 trigger_write_time_update(fsp);
287 dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
288 if ((lp_store_dos_attributes(SNUM(fsp->conn)) ||
289 MAP_ARCHIVE(fsp->conn)) &&
290 !IS_DOS_ARCHIVE(dosmode)) {
291 file_set_dosmode(fsp->conn,fsp->fsp_name,
292 dosmode | aARCH,&st,
293 NULL,
294 false);
295 }
296
297 /*
298 * If this is the first write and we have an exclusive oplock then setup
299 * the write cache.
300 */
301
302 if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
303 setup_write_cache(fsp, st.st_size);
304 wcp = fsp->wcp;
305 }
306 }
307 }
308
309#ifdef WITH_PROFILE
310 DO_PROFILE_INC(writecache_total_writes);
311 if (!fsp->oplock_type) {
312 DO_PROFILE_INC(writecache_non_oplock_writes);
313 }
314#endif
315
316 /*
317 * If this file is level II oplocked then we need
318 * to grab the shared memory lock and inform all
319 * other files with a level II lock that they need
320 * to flush their read caches. We keep the lock over
321 * the shared memory area whilst doing this.
322 */
323
324 release_level_2_oplocks_on_change(fsp);
325
326#ifdef WITH_PROFILE
327 if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
328 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
329nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
330 profile_p->writecache_init_writes,
331 profile_p->writecache_abutted_writes,
332 profile_p->writecache_total_writes,
333 profile_p->writecache_non_oplock_writes,
334 profile_p->writecache_allocated_write_caches,
335 profile_p->writecache_num_write_caches,
336 profile_p->writecache_direct_writes,
337 profile_p->writecache_num_perfect_writes,
338 profile_p->writecache_read_hits ));
339
340 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
341 profile_p->writecache_flushed_writes[SEEK_FLUSH],
342 profile_p->writecache_flushed_writes[READ_FLUSH],
343 profile_p->writecache_flushed_writes[WRITE_FLUSH],
344 profile_p->writecache_flushed_writes[READRAW_FLUSH],
345 profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
346 profile_p->writecache_flushed_writes[CLOSE_FLUSH],
347 profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
348 }
349#endif
350
351 if (wcp && req->unread_bytes) {
352 /* If we're using receivefile don't
353 * deal with a write cache.
354 */
355 flush_write_cache(fsp, WRITE_FLUSH);
356 delete_write_cache(fsp);
357 wcp = NULL;
358 }
359
360 if(!wcp) {
361 DO_PROFILE_INC(writecache_direct_writes);
362 total_written = real_write_file(req, fsp, data, pos, n);
363 return total_written;
364 }
365
366 DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
367 fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
368
369 fsp->fh->pos = pos + n;
370
371 /*
372 * If we have active cache and it isn't contiguous then we flush.
373 * NOTE: There is a small problem with running out of disk ....
374 */
375
376 if (wcp->data_size) {
377 bool cache_flush_needed = False;
378
379 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
380
381 /* ASCII art.... JRA.
382
383 +--------------+-----
384 | Cached data | Rest of allocated cache buffer....
385 +--------------+-----
386
387 +-------------------+
388 | Data to write |
389 +-------------------+
390
391 */
392
393 /*
394 * Start of write overlaps or abutts the existing data.
395 */
396
397 size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
398
399 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
400
401 /*
402 * Update the current buffer size with the new data.
403 */
404
405 if(pos + data_used > wcp->offset + wcp->data_size) {
406 wcp->data_size = pos + data_used - wcp->offset;
407 }
408
409 /*
410 * Update the file size if changed.
411 */
412
413 if (wcp->offset + wcp->data_size > wcp->file_size) {
414 if (wcp_file_size_change(fsp) == -1) {
415 return -1;
416 }
417 }
418
419 /*
420 * If we used all the data then
421 * return here.
422 */
423
424 if(n == data_used) {
425 return n;
426 } else {
427 cache_flush_needed = True;
428 }
429 /*
430 * Move the start of data forward by the amount used,
431 * cut down the amount left by the same amount.
432 */
433
434 data += data_used;
435 pos += data_used;
436 n -= data_used;
437
438 DO_PROFILE_INC(writecache_abutted_writes);
439 total_written = data_used;
440
441 write_path = 1;
442
443 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
444 (pos + n <= wcp->offset + wcp->alloc_size)) {
445
446 /* ASCII art.... JRA.
447
448 +---------------+
449 | Cache buffer |
450 +---------------+
451
452 +-------------------+
453 | Data to write |
454 +-------------------+
455
456 */
457
458 /*
459 * End of write overlaps the existing data.
460 */
461
462 size_t data_used = pos + n - wcp->offset;
463
464 memcpy(wcp->data, data + n - data_used, data_used);
465
466 /*
467 * Update the current buffer size with the new data.
468 */
469
470 if(pos + n > wcp->offset + wcp->data_size) {
471 wcp->data_size = pos + n - wcp->offset;
472 }
473
474 /*
475 * Update the file size if changed.
476 */
477
478 if (wcp->offset + wcp->data_size > wcp->file_size) {
479 if (wcp_file_size_change(fsp) == -1) {
480 return -1;
481 }
482 }
483
484 /*
485 * We don't need to move the start of data, but we
486 * cut down the amount left by the amount used.
487 */
488
489 n -= data_used;
490
491 /*
492 * We cannot have used all the data here.
493 */
494
495 cache_flush_needed = True;
496
497 DO_PROFILE_INC(writecache_abutted_writes);
498 total_written = data_used;
499
500 write_path = 2;
501
502 } else if ( (pos >= wcp->file_size) &&
503 (wcp->offset + wcp->data_size == wcp->file_size) &&
504 (pos > wcp->offset + wcp->data_size) &&
505 (pos < wcp->offset + wcp->alloc_size) ) {
506
507 /* ASCII art.... JRA.
508
509 End of file ---->|
510
511 +---------------+---------------+
512 | Cached data | Cache buffer |
513 +---------------+---------------+
514
515 +-------------------+
516 | Data to write |
517 +-------------------+
518
519 */
520
521 /*
522 * Non-contiguous write part of which fits within
523 * the cache buffer and is extending the file
524 * and the cache contents reflect the current
525 * data up to the current end of the file.
526 */
527
528 size_t data_used;
529
530 if(pos + n <= wcp->offset + wcp->alloc_size) {
531 data_used = n;
532 } else {
533 data_used = wcp->offset + wcp->alloc_size - pos;
534 }
535
536 /*
537 * Fill in the non-continuous area with zeros.
538 */
539
540 memset(wcp->data + wcp->data_size, '\0',
541 pos - (wcp->offset + wcp->data_size) );
542
543 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
544
545 /*
546 * Update the current buffer size with the new data.
547 */
548
549 if(pos + data_used > wcp->offset + wcp->data_size) {
550 wcp->data_size = pos + data_used - wcp->offset;
551 }
552
553 /*
554 * Update the file size if changed.
555 */
556
557 if (wcp->offset + wcp->data_size > wcp->file_size) {
558 if (wcp_file_size_change(fsp) == -1) {
559 return -1;
560 }
561 }
562
563 /*
564 * If we used all the data then
565 * return here.
566 */
567
568 if(n == data_used) {
569 return n;
570 } else {
571 cache_flush_needed = True;
572 }
573
574 /*
575 * Move the start of data forward by the amount used,
576 * cut down the amount left by the same amount.
577 */
578
579 data += data_used;
580 pos += data_used;
581 n -= data_used;
582
583 DO_PROFILE_INC(writecache_abutted_writes);
584 total_written = data_used;
585
586 write_path = 3;
587
588 } else if ( (pos >= wcp->file_size) &&
589 (n == 1) &&
590 (wcp->file_size == wcp->offset + wcp->data_size) &&
591 (pos < wcp->file_size + wcp->alloc_size)) {
592
593 /*
594
595 End of file ---->|
596
597 +---------------+---------------+
598 | Cached data | Cache buffer |
599 +---------------+---------------+
600
601 |<------- allocated size ---------------->|
602
603 +--------+
604 | 1 Byte |
605 +--------+
606
607 MS-Office seems to do this a lot to determine if there's enough
608 space on the filesystem to write a new file.
609
610 Change to :
611
612 End of file ---->|
613 +-----------------------+--------+
614 | Zeroed Cached data | 1 Byte |
615 +-----------------------+--------+
616 */
617
618 flush_write_cache(fsp, WRITE_FLUSH);
619 wcp->offset = wcp->file_size;
620 wcp->data_size = pos - wcp->file_size + 1;
621 memset(wcp->data, '\0', wcp->data_size);
622 memcpy(wcp->data + wcp->data_size-1, data, 1);
623
624 /*
625 * Update the file size if changed.
626 */
627
628 if (wcp->offset + wcp->data_size > wcp->file_size) {
629 if (wcp_file_size_change(fsp) == -1) {
630 return -1;
631 }
632 }
633
634 return n;
635
636 } else {
637
638 /* ASCII art..... JRA.
639
640 Case 1).
641
642 +---------------+---------------+
643 | Cached data | Cache buffer |
644 +---------------+---------------+
645
646 +-------------------+
647 | Data to write |
648 +-------------------+
649
650 Case 2).
651
652 +---------------+---------------+
653 | Cached data | Cache buffer |
654 +---------------+---------------+
655
656 +-------------------+
657 | Data to write |
658 +-------------------+
659
660 Case 3).
661
662 +---------------+---------------+
663 | Cached data | Cache buffer |
664 +---------------+---------------+
665
666 +-----------------------------------------------------+
667 | Data to write |
668 +-----------------------------------------------------+
669
670 */
671
672 /*
673 * Write is bigger than buffer, or there is no overlap on the
674 * low or high ends.
675 */
676
677 DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
678len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
679
680 /*
681 * If write would fit in the cache, and is larger than
682 * the data already in the cache, flush the cache and
683 * preferentially copy the data new data into it. Otherwise
684 * just write the data directly.
685 */
686
687 if ( n <= wcp->alloc_size && n > wcp->data_size) {
688 cache_flush_needed = True;
689 } else {
690 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
691
692 /*
693 * If the write overlaps the entire cache, then
694 * discard the current contents of the cache.
695 * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
696 */
697
698 if ((pos <= wcp->offset) &&
699 (pos + n >= wcp->offset + wcp->data_size) ) {
700 DEBUG(9,("write_file: discarding overwritten write \
701cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
702 wcp->data_size = 0;
703 }
704
705 DO_PROFILE_INC(writecache_direct_writes);
706 if (ret == -1) {
707 return ret;
708 }
709
710 if (pos + ret > wcp->file_size) {
711 wcp->file_size = pos + ret;
712 }
713
714 return ret;
715 }
716
717 write_path = 4;
718
719 }
720
721 if (cache_flush_needed) {
722 DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
723n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
724 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
725 (double)wcp->offset, (unsigned int)wcp->data_size ));
726
727 flush_write_cache(fsp, WRITE_FLUSH);
728 }
729 }
730
731 /*
732 * If the write request is bigger than the cache
733 * size, write it all out.
734 */
735
736 if (n > wcp->alloc_size ) {
737 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
738 if (ret == -1) {
739 return -1;
740 }
741
742 if (pos + ret > wcp->file_size) {
743 wcp->file_size = pos + n;
744 }
745
746 DO_PROFILE_INC(writecache_direct_writes);
747 return total_written + n;
748 }
749
750 /*
751 * If there's any data left, cache it.
752 */
753
754 if (n) {
755#ifdef WITH_PROFILE
756 if (wcp->data_size) {
757 DO_PROFILE_INC(writecache_abutted_writes);
758 } else {
759 DO_PROFILE_INC(writecache_init_writes);
760 }
761#endif
762 memcpy(wcp->data+wcp->data_size, data, n);
763 if (wcp->data_size == 0) {
764 wcp->offset = pos;
765 DO_PROFILE_INC(writecache_num_write_caches);
766 }
767 wcp->data_size += n;
768
769 /*
770 * Update the file size if changed.
771 */
772
773 if (wcp->offset + wcp->data_size > wcp->file_size) {
774 if (wcp_file_size_change(fsp) == -1) {
775 return -1;
776 }
777 }
778 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
779 (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
780
781 total_written += n;
782 return total_written; /* .... that's a write :) */
783 }
784
785 return total_written;
786}
787
788/****************************************************************************
789 Delete the write cache structure.
790****************************************************************************/
791
792void delete_write_cache(files_struct *fsp)
793{
794 write_cache *wcp;
795
796 if(!fsp) {
797 return;
798 }
799
800 if(!(wcp = fsp->wcp)) {
801 return;
802 }
803
804 DO_PROFILE_DEC(writecache_allocated_write_caches);
805 allocated_write_caches--;
806
807 SMB_ASSERT(wcp->data_size == 0);
808
809 SAFE_FREE(wcp->data);
810 SAFE_FREE(fsp->wcp);
811
812 DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
813}
814
815/****************************************************************************
816 Setup the write cache structure.
817****************************************************************************/
818
819static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
820{
821 ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
822 write_cache *wcp;
823
824 if (allocated_write_caches >= MAX_WRITE_CACHES) {
825 return False;
826 }
827
828 if(alloc_size == 0 || fsp->wcp) {
829 return False;
830 }
831
832 if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
833 DEBUG(0,("setup_write_cache: malloc fail.\n"));
834 return False;
835 }
836
837 wcp->file_size = file_size;
838 wcp->offset = 0;
839 wcp->alloc_size = alloc_size;
840 wcp->data_size = 0;
841 if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
842 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
843 (unsigned int)wcp->alloc_size ));
844 SAFE_FREE(wcp);
845 return False;
846 }
847
848 memset(wcp->data, '\0', wcp->alloc_size );
849
850 fsp->wcp = wcp;
851 DO_PROFILE_INC(writecache_allocated_write_caches);
852 allocated_write_caches++;
853
854 DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
855 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
856
857 return True;
858}
859
860/****************************************************************************
861 Cope with a size change.
862****************************************************************************/
863
864void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
865{
866 if(fsp->wcp) {
867 /* The cache *must* have been flushed before we do this. */
868 if (fsp->wcp->data_size != 0) {
869 char *msg;
870 asprintf(&msg, "set_filelen_write_cache: size change "
871 "on file %s with write cache size = %lu\n",
872 fsp->fsp_name,
873 (unsigned long)fsp->wcp->data_size);
874 smb_panic(msg);
875 }
876 fsp->wcp->file_size = file_size;
877 }
878}
879
880/*******************************************************************
881 Flush a write cache struct to disk.
882********************************************************************/
883
884ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
885{
886 write_cache *wcp = fsp->wcp;
887 size_t data_size;
888 ssize_t ret;
889
890 if(!wcp || !wcp->data_size) {
891 return 0;
892 }
893
894 data_size = wcp->data_size;
895 wcp->data_size = 0;
896
897 DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
898
899 DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
900 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
901
902#ifdef WITH_PROFILE
903 if(data_size == wcp->alloc_size) {
904 DO_PROFILE_INC(writecache_num_perfect_writes);
905 }
906#endif
907
908 ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
909
910 /*
911 * Ensure file size if kept up to date if write extends file.
912 */
913
914 if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
915 wcp->file_size = wcp->offset + ret;
916 }
917
918 return ret;
919}
920
921/*******************************************************************
922sync a file
923********************************************************************/
924
925NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
926{
927 if (fsp->fh->fd == -1)
928 return NT_STATUS_INVALID_HANDLE;
929
930 if (lp_strict_sync(SNUM(conn)) &&
931 (lp_syncalways(SNUM(conn)) || write_through)) {
932 int ret = flush_write_cache(fsp, SYNC_FLUSH);
933 if (ret == -1) {
934 return map_nt_error_from_unix(errno);
935 }
936 ret = SMB_VFS_FSYNC(fsp);
937 if (ret == -1) {
938 return map_nt_error_from_unix(errno);
939 }
940 }
941 return NT_STATUS_OK;
942}
943
944/************************************************************
945 Perform a stat whether a valid fd or not.
946************************************************************/
947
948int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
949{
950 if (fsp->fh->fd == -1) {
951 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
952 } else {
953 return SMB_VFS_FSTAT(fsp, pst);
954 }
955}
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