source: branches/samba-3.3.x/source/smbd/fileio.c@ 401

Last change on this file since 401 was 206, checked in by Herwig Bauernfeind, 16 years ago

Import Samba 3.3 branch at 3.0.0 level (psmedley's port)
File size: 24.1 KB
Line 
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 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, fsp);
225}
226
227void trigger_write_time_update_immediate(struct files_struct *fsp)
228{
229 if (fsp->write_time_forced) {
230 /*
231 * No point - "sticky" write times
232 * in effect.
233 */
234 return;
235 }
236
237 TALLOC_FREE(fsp->update_write_time_event);
238 DEBUG(5, ("Update write time immediate on %s\n", fsp->fsp_name));
239
240 fsp->update_write_time_triggered = true;
241
242 fsp->update_write_time_on_close = false;
243 update_write_time(fsp);
244}
245
246/****************************************************************************
247 Write to a file.
248****************************************************************************/
249
250ssize_t write_file(struct smb_request *req,
251 files_struct *fsp,
252 const char *data,
253 SMB_OFF_T pos,
254 size_t n)
255{
256 write_cache *wcp = fsp->wcp;
257 ssize_t total_written = 0;
258 int write_path = -1;
259
260 if (fsp->print_file) {
261 fstring sharename;
262 uint32 jobid;
263
264 if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
265 DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
266 (unsigned int)fsp->rap_print_jobid ));
267 errno = EBADF;
268 return -1;
269 }
270
271 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
272 }
273
274 if (!fsp->can_write) {
275 errno = EPERM;
276 return -1;
277 }
278
279 if (!fsp->modified) {
280 SMB_STRUCT_STAT st;
281 fsp->modified = True;
282
283 if (SMB_VFS_FSTAT(fsp, &st) == 0) {
284 int dosmode;
285 trigger_write_time_update(fsp);
286 dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
287 if ((lp_store_dos_attributes(SNUM(fsp->conn)) ||
288 MAP_ARCHIVE(fsp->conn)) &&
289 !IS_DOS_ARCHIVE(dosmode)) {
290 file_set_dosmode(fsp->conn,fsp->fsp_name,
291 dosmode | aARCH,&st,
292 NULL,
293 false);
294 }
295
296 /*
297 * If this is the first write and we have an exclusive oplock then setup
298 * the write cache.
299 */
300
301 if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
302 setup_write_cache(fsp, st.st_size);
303 wcp = fsp->wcp;
304 }
305 }
306 }
307
308#ifdef WITH_PROFILE
309 DO_PROFILE_INC(writecache_total_writes);
310 if (!fsp->oplock_type) {
311 DO_PROFILE_INC(writecache_non_oplock_writes);
312 }
313#endif
314
315 /*
316 * If this file is level II oplocked then we need
317 * to grab the shared memory lock and inform all
318 * other files with a level II lock that they need
319 * to flush their read caches. We keep the lock over
320 * the shared memory area whilst doing this.
321 */
322
323 release_level_2_oplocks_on_change(fsp);
324
325#ifdef WITH_PROFILE
326 if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
327 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
328nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
329 profile_p->writecache_init_writes,
330 profile_p->writecache_abutted_writes,
331 profile_p->writecache_total_writes,
332 profile_p->writecache_non_oplock_writes,
333 profile_p->writecache_allocated_write_caches,
334 profile_p->writecache_num_write_caches,
335 profile_p->writecache_direct_writes,
336 profile_p->writecache_num_perfect_writes,
337 profile_p->writecache_read_hits ));
338
339 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
340 profile_p->writecache_flushed_writes[SEEK_FLUSH],
341 profile_p->writecache_flushed_writes[READ_FLUSH],
342 profile_p->writecache_flushed_writes[WRITE_FLUSH],
343 profile_p->writecache_flushed_writes[READRAW_FLUSH],
344 profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
345 profile_p->writecache_flushed_writes[CLOSE_FLUSH],
346 profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
347 }
348#endif
349
350 if (wcp && req->unread_bytes) {
351 /* If we're using receivefile don't
352 * deal with a write cache.
353 */
354 flush_write_cache(fsp, WRITE_FLUSH);
355 delete_write_cache(fsp);
356 wcp = NULL;
357 }
358
359 if(!wcp) {
360 DO_PROFILE_INC(writecache_direct_writes);
361 total_written = real_write_file(req, fsp, data, pos, n);
362 return total_written;
363 }
364
365 DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
366 fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
367
368 fsp->fh->pos = pos + n;
369
370 /*
371 * If we have active cache and it isn't contiguous then we flush.
372 * NOTE: There is a small problem with running out of disk ....
373 */
374
375 if (wcp->data_size) {
376 bool cache_flush_needed = False;
377
378 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
379
380 /* ASCII art.... JRA.
381
382 +--------------+-----
383 | Cached data | Rest of allocated cache buffer....
384 +--------------+-----
385
386 +-------------------+
387 | Data to write |
388 +-------------------+
389
390 */
391
392 /*
393 * Start of write overlaps or abutts the existing data.
394 */
395
396 size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
397
398 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
399
400 /*
401 * Update the current buffer size with the new data.
402 */
403
404 if(pos + data_used > wcp->offset + wcp->data_size) {
405 wcp->data_size = pos + data_used - wcp->offset;
406 }
407
408 /*
409 * Update the file size if changed.
410 */
411
412 if (wcp->offset + wcp->data_size > wcp->file_size) {
413 if (wcp_file_size_change(fsp) == -1) {
414 return -1;
415 }
416 }
417
418 /*
419 * If we used all the data then
420 * return here.
421 */
422
423 if(n == data_used) {
424 return n;
425 } else {
426 cache_flush_needed = True;
427 }
428 /*
429 * Move the start of data forward by the amount used,
430 * cut down the amount left by the same amount.
431 */
432
433 data += data_used;
434 pos += data_used;
435 n -= data_used;
436
437 DO_PROFILE_INC(writecache_abutted_writes);
438 total_written = data_used;
439
440 write_path = 1;
441
442 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
443 (pos + n <= wcp->offset + wcp->alloc_size)) {
444
445 /* ASCII art.... JRA.
446
447 +---------------+
448 | Cache buffer |
449 +---------------+
450
451 +-------------------+
452 | Data to write |
453 +-------------------+
454
455 */
456
457 /*
458 * End of write overlaps the existing data.
459 */
460
461 size_t data_used = pos + n - wcp->offset;
462
463 memcpy(wcp->data, data + n - data_used, data_used);
464
465 /*
466 * Update the current buffer size with the new data.
467 */
468
469 if(pos + n > wcp->offset + wcp->data_size) {
470 wcp->data_size = pos + n - wcp->offset;
471 }
472
473 /*
474 * Update the file size if changed.
475 */
476
477 if (wcp->offset + wcp->data_size > wcp->file_size) {
478 if (wcp_file_size_change(fsp) == -1) {
479 return -1;
480 }
481 }
482
483 /*
484 * We don't need to move the start of data, but we
485 * cut down the amount left by the amount used.
486 */
487
488 n -= data_used;
489
490 /*
491 * We cannot have used all the data here.
492 */
493
494 cache_flush_needed = True;
495
496 DO_PROFILE_INC(writecache_abutted_writes);
497 total_written = data_used;
498
499 write_path = 2;
500
501 } else if ( (pos >= wcp->file_size) &&
502 (wcp->offset + wcp->data_size == wcp->file_size) &&
503 (pos > wcp->offset + wcp->data_size) &&
504 (pos < wcp->offset + wcp->alloc_size) ) {
505
506 /* ASCII art.... JRA.
507
508 End of file ---->|
509
510 +---------------+---------------+
511 | Cached data | Cache buffer |
512 +---------------+---------------+
513
514 +-------------------+
515 | Data to write |
516 +-------------------+
517
518 */
519
520 /*
521 * Non-contiguous write part of which fits within
522 * the cache buffer and is extending the file
523 * and the cache contents reflect the current
524 * data up to the current end of the file.
525 */
526
527 size_t data_used;
528
529 if(pos + n <= wcp->offset + wcp->alloc_size) {
530 data_used = n;
531 } else {
532 data_used = wcp->offset + wcp->alloc_size - pos;
533 }
534
535 /*
536 * Fill in the non-continuous area with zeros.
537 */
538
539 memset(wcp->data + wcp->data_size, '\0',
540 pos - (wcp->offset + wcp->data_size) );
541
542 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
543
544 /*
545 * Update the current buffer size with the new data.
546 */
547
548 if(pos + data_used > wcp->offset + wcp->data_size) {
549 wcp->data_size = pos + data_used - wcp->offset;
550 }
551
552 /*
553 * Update the file size if changed.
554 */
555
556 if (wcp->offset + wcp->data_size > wcp->file_size) {
557 if (wcp_file_size_change(fsp) == -1) {
558 return -1;
559 }
560 }
561
562 /*
563 * If we used all the data then
564 * return here.
565 */
566
567 if(n == data_used) {
568 return n;
569 } else {
570 cache_flush_needed = True;
571 }
572
573 /*
574 * Move the start of data forward by the amount used,
575 * cut down the amount left by the same amount.
576 */
577
578 data += data_used;
579 pos += data_used;
580 n -= data_used;
581
582 DO_PROFILE_INC(writecache_abutted_writes);
583 total_written = data_used;
584
585 write_path = 3;
586
587 } else if ( (pos >= wcp->file_size) &&
588 (n == 1) &&
589 (wcp->file_size == wcp->offset + wcp->data_size) &&
590 (pos < wcp->file_size + wcp->alloc_size)) {
591
592 /*
593
594 End of file ---->|
595
596 +---------------+---------------+
597 | Cached data | Cache buffer |
598 +---------------+---------------+
599
600 |<------- allocated size ---------------->|
601
602 +--------+
603 | 1 Byte |
604 +--------+
605
606 MS-Office seems to do this a lot to determine if there's enough
607 space on the filesystem to write a new file.
608
609 Change to :
610
611 End of file ---->|
612 +-----------------------+--------+
613 | Zeroed Cached data | 1 Byte |
614 +-----------------------+--------+
615 */
616
617 flush_write_cache(fsp, WRITE_FLUSH);
618 wcp->offset = wcp->file_size;
619 wcp->data_size = pos - wcp->file_size + 1;
620 memset(wcp->data, '\0', wcp->data_size);
621 memcpy(wcp->data + wcp->data_size-1, data, 1);
622
623 /*
624 * Update the file size if changed.
625 */
626
627 if (wcp->offset + wcp->data_size > wcp->file_size) {
628 if (wcp_file_size_change(fsp) == -1) {
629 return -1;
630 }
631 }
632
633 return n;
634
635 } else {
636
637 /* ASCII art..... JRA.
638
639 Case 1).
640
641 +---------------+---------------+
642 | Cached data | Cache buffer |
643 +---------------+---------------+
644
645 +-------------------+
646 | Data to write |
647 +-------------------+
648
649 Case 2).
650
651 +---------------+---------------+
652 | Cached data | Cache buffer |
653 +---------------+---------------+
654
655 +-------------------+
656 | Data to write |
657 +-------------------+
658
659 Case 3).
660
661 +---------------+---------------+
662 | Cached data | Cache buffer |
663 +---------------+---------------+
664
665 +-----------------------------------------------------+
666 | Data to write |
667 +-----------------------------------------------------+
668
669 */
670
671 /*
672 * Write is bigger than buffer, or there is no overlap on the
673 * low or high ends.
674 */
675
676 DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
677len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
678
679 /*
680 * If write would fit in the cache, and is larger than
681 * the data already in the cache, flush the cache and
682 * preferentially copy the data new data into it. Otherwise
683 * just write the data directly.
684 */
685
686 if ( n <= wcp->alloc_size && n > wcp->data_size) {
687 cache_flush_needed = True;
688 } else {
689 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
690
691 /*
692 * If the write overlaps the entire cache, then
693 * discard the current contents of the cache.
694 * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
695 */
696
697 if ((pos <= wcp->offset) &&
698 (pos + n >= wcp->offset + wcp->data_size) ) {
699 DEBUG(9,("write_file: discarding overwritten write \
700cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
701 wcp->data_size = 0;
702 }
703
704 DO_PROFILE_INC(writecache_direct_writes);
705 if (ret == -1) {
706 return ret;
707 }
708
709 if (pos + ret > wcp->file_size) {
710 wcp->file_size = pos + ret;
711 }
712
713 return ret;
714 }
715
716 write_path = 4;
717
718 }
719
720 if (cache_flush_needed) {
721 DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
722n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
723 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
724 (double)wcp->offset, (unsigned int)wcp->data_size ));
725
726 flush_write_cache(fsp, WRITE_FLUSH);
727 }
728 }
729
730 /*
731 * If the write request is bigger than the cache
732 * size, write it all out.
733 */
734
735 if (n > wcp->alloc_size ) {
736 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
737 if (ret == -1) {
738 return -1;
739 }
740
741 if (pos + ret > wcp->file_size) {
742 wcp->file_size = pos + n;
743 }
744
745 DO_PROFILE_INC(writecache_direct_writes);
746 return total_written + n;
747 }
748
749 /*
750 * If there's any data left, cache it.
751 */
752
753 if (n) {
754#ifdef WITH_PROFILE
755 if (wcp->data_size) {
756 DO_PROFILE_INC(writecache_abutted_writes);
757 } else {
758 DO_PROFILE_INC(writecache_init_writes);
759 }
760#endif
761 memcpy(wcp->data+wcp->data_size, data, n);
762 if (wcp->data_size == 0) {
763 wcp->offset = pos;
764 DO_PROFILE_INC(writecache_num_write_caches);
765 }
766 wcp->data_size += n;
767
768 /*
769 * Update the file size if changed.
770 */
771
772 if (wcp->offset + wcp->data_size > wcp->file_size) {
773 if (wcp_file_size_change(fsp) == -1) {
774 return -1;
775 }
776 }
777 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
778 (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
779
780 total_written += n;
781 return total_written; /* .... that's a write :) */
782 }
783
784 return total_written;
785}
786
787/****************************************************************************
788 Delete the write cache structure.
789****************************************************************************/
790
791void delete_write_cache(files_struct *fsp)
792{
793 write_cache *wcp;
794
795 if(!fsp) {
796 return;
797 }
798
799 if(!(wcp = fsp->wcp)) {
800 return;
801 }
802
803 DO_PROFILE_DEC(writecache_allocated_write_caches);
804 allocated_write_caches--;
805
806 SMB_ASSERT(wcp->data_size == 0);
807
808 SAFE_FREE(wcp->data);
809 SAFE_FREE(fsp->wcp);
810
811 DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
812}
813
814/****************************************************************************
815 Setup the write cache structure.
816****************************************************************************/
817
818static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
819{
820 ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
821 write_cache *wcp;
822
823 if (allocated_write_caches >= MAX_WRITE_CACHES) {
824 return False;
825 }
826
827 if(alloc_size == 0 || fsp->wcp) {
828 return False;
829 }
830
831 if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
832 DEBUG(0,("setup_write_cache: malloc fail.\n"));
833 return False;
834 }
835
836 wcp->file_size = file_size;
837 wcp->offset = 0;
838 wcp->alloc_size = alloc_size;
839 wcp->data_size = 0;
840 if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
841 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
842 (unsigned int)wcp->alloc_size ));
843 SAFE_FREE(wcp);
844 return False;
845 }
846
847 memset(wcp->data, '\0', wcp->alloc_size );
848
849 fsp->wcp = wcp;
850 DO_PROFILE_INC(writecache_allocated_write_caches);
851 allocated_write_caches++;
852
853 DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
854 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
855
856 return True;
857}
858
859/****************************************************************************
860 Cope with a size change.
861****************************************************************************/
862
863void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
864{
865 if(fsp->wcp) {
866 /* The cache *must* have been flushed before we do this. */
867 if (fsp->wcp->data_size != 0) {
868 char *msg;
869 if (asprintf(&msg, "set_filelen_write_cache: size change "
870 "on file %s with write cache size = %lu\n",
871 fsp->fsp_name,
872 (unsigned long)fsp->wcp->data_size) != -1) {
873 smb_panic(msg);
874 } else {
875 smb_panic("set_filelen_write_cache");
876 }
877 }
878 fsp->wcp->file_size = file_size;
879 }
880}
881
882/*******************************************************************
883 Flush a write cache struct to disk.
884********************************************************************/
885
886ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
887{
888 write_cache *wcp = fsp->wcp;
889 size_t data_size;
890 ssize_t ret;
891
892 if(!wcp || !wcp->data_size) {
893 return 0;
894 }
895
896 data_size = wcp->data_size;
897 wcp->data_size = 0;
898
899 DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
900
901 DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
902 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
903
904#ifdef WITH_PROFILE
905 if(data_size == wcp->alloc_size) {
906 DO_PROFILE_INC(writecache_num_perfect_writes);
907 }
908#endif
909
910 ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
911
912 /*
913 * Ensure file size if kept up to date if write extends file.
914 */
915
916 if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
917 wcp->file_size = wcp->offset + ret;
918 }
919
920 return ret;
921}
922
923/*******************************************************************
924sync a file
925********************************************************************/
926
927NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
928{
929 if (fsp->fh->fd == -1)
930 return NT_STATUS_INVALID_HANDLE;
931
932 if (lp_strict_sync(SNUM(conn)) &&
933 (lp_syncalways(SNUM(conn)) || write_through)) {
934 int ret = flush_write_cache(fsp, SYNC_FLUSH);
935 if (ret == -1) {
936 return map_nt_error_from_unix(errno);
937 }
938 ret = SMB_VFS_FSYNC(fsp);
939 if (ret == -1) {
940 return map_nt_error_from_unix(errno);
941 }
942 }
943 return NT_STATUS_OK;
944}
945
946/************************************************************
947 Perform a stat whether a valid fd or not.
948************************************************************/
949
950int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
951{
952 if (fsp->fh->fd == -1) {
953 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
954 } else {
955 return SMB_VFS_FSTAT(fsp, pst);
956 }
957}
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