Remove redundant parameter fd from SMB_VFS_FTRUNCATE().
[tprouty/samba.git] / source / 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
24 static bool setup_write_cache(files_struct *, SMB_OFF_T);
25
26 /****************************************************************************
27  Read from write cache if we can.
28 ****************************************************************************/
29
30 static 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
53 ssize_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;
79 tryagain:
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 */
113 static unsigned int allocated_write_caches;
114
115 /****************************************************************************
116  *Really* write to a file.
117 ****************************************************************************/
118
119 static 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                 /*
146                  * It turns out that setting the last write time from a Windows
147                  * client stops any subsequent writes from updating the write time.
148                  * Doing this after the write gives a race condition here where
149                  * a stat may see the changed write time before we reset it here,
150                  * but it's cheaper than having to store the write time in shared
151                  * memory and look it up using dev/inode across all running smbd's.
152                  * The 99% solution will hopefully be good enough in this case. JRA.
153                  */
154
155                 if (!null_timespec(fsp->pending_modtime)) {
156                         set_filetime(fsp->conn, fsp->fsp_name,
157                                         fsp->pending_modtime);
158
159                         /* If we didn't get the "set modtime" call ourselves, we must
160                            store the last write time to restore on close. JRA. */
161                         if (!fsp->pending_modtime_owner) {
162                                 fsp->last_write_time = timespec_current();
163                         }
164                 }
165
166 /* Yes - this is correct - writes don't update this. JRA. */
167 /* Found by Samba4 tests. */
168 #if 0
169                 fsp->position_information = fsp->pos;
170 #endif
171         }
172
173         return ret;
174 }
175
176 /****************************************************************************
177  File size cache change.
178  Updates size on disk but doesn't flush the cache.
179 ****************************************************************************/
180
181 static int wcp_file_size_change(files_struct *fsp)
182 {
183         int ret;
184         write_cache *wcp = fsp->wcp;
185
186         wcp->file_size = wcp->offset + wcp->data_size;
187         ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
188         if (ret == -1) {
189                 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f error %s\n",
190                         fsp->fsp_name, (double)wcp->file_size, strerror(errno) ));
191         }
192         return ret;
193 }
194
195 /****************************************************************************
196  Write to a file.
197 ****************************************************************************/
198
199 ssize_t write_file(struct smb_request *req,
200                         files_struct *fsp,
201                         const char *data,
202                         SMB_OFF_T pos,
203                         size_t n)
204 {
205         write_cache *wcp = fsp->wcp;
206         ssize_t total_written = 0;
207         int write_path = -1;
208
209         if (fsp->print_file) {
210                 fstring sharename;
211                 uint32 jobid;
212
213                 if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
214                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
215                                                 (unsigned int)fsp->rap_print_jobid ));
216                         errno = EBADF;
217                         return -1;
218                 }
219
220                 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
221         }
222
223         if (!fsp->can_write) {
224                 errno = EPERM;
225                 return -1;
226         }
227
228         if (!fsp->modified) {
229                 SMB_STRUCT_STAT st;
230                 fsp->modified = True;
231
232                 if (SMB_VFS_FSTAT(fsp, &st) == 0) {
233                         int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
234                         if ((lp_store_dos_attributes(SNUM(fsp->conn)) ||
235                                         MAP_ARCHIVE(fsp->conn)) &&
236                                         !IS_DOS_ARCHIVE(dosmode)) {
237                                 file_set_dosmode(fsp->conn,fsp->fsp_name,
238                                                 dosmode | aARCH,&st,
239                                                 NULL,
240                                                 false);
241                         }
242
243                         /*
244                          * If this is the first write and we have an exclusive oplock then setup
245                          * the write cache.
246                          */
247
248                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
249                                 setup_write_cache(fsp, st.st_size);
250                                 wcp = fsp->wcp;
251                         }
252                 }
253         }
254
255 #ifdef WITH_PROFILE
256         DO_PROFILE_INC(writecache_total_writes);
257         if (!fsp->oplock_type) {
258                 DO_PROFILE_INC(writecache_non_oplock_writes);
259         }
260 #endif
261
262         /*
263          * If this file is level II oplocked then we need
264          * to grab the shared memory lock and inform all
265          * other files with a level II lock that they need
266          * to flush their read caches. We keep the lock over
267          * the shared memory area whilst doing this.
268          */
269
270         release_level_2_oplocks_on_change(fsp);
271
272 #ifdef WITH_PROFILE
273         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
274                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
275 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
276                         profile_p->writecache_init_writes,
277                         profile_p->writecache_abutted_writes,
278                         profile_p->writecache_total_writes,
279                         profile_p->writecache_non_oplock_writes,
280                         profile_p->writecache_allocated_write_caches,
281                         profile_p->writecache_num_write_caches,
282                         profile_p->writecache_direct_writes,
283                         profile_p->writecache_num_perfect_writes,
284                         profile_p->writecache_read_hits ));
285
286                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
287                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
288                         profile_p->writecache_flushed_writes[READ_FLUSH],
289                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
290                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
291                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
292                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
293                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
294         }
295 #endif
296
297         if (wcp && req->unread_bytes) {
298                 /* If we're using receivefile don't
299                  * deal with a write cache.
300                  */
301                 flush_write_cache(fsp, WRITE_FLUSH);
302                 delete_write_cache(fsp);
303                 wcp = NULL;
304         }
305
306         if(!wcp) {
307                 DO_PROFILE_INC(writecache_direct_writes);
308                 total_written = real_write_file(req, fsp, data, pos, n);
309                 return total_written;
310         }
311
312         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
313                 fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
314
315         fsp->fh->pos = pos + n;
316
317         /*
318          * If we have active cache and it isn't contiguous then we flush.
319          * NOTE: There is a small problem with running out of disk ....
320          */
321
322         if (wcp->data_size) {
323                 bool cache_flush_needed = False;
324
325                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
326       
327                         /* ASCII art.... JRA.
328
329       +--------------+-----
330       | Cached data  | Rest of allocated cache buffer....
331       +--------------+-----
332
333             +-------------------+
334             | Data to write     |
335             +-------------------+
336
337                         */
338
339                         /*
340                          * Start of write overlaps or abutts the existing data.
341                          */
342
343                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
344
345                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
346
347                         /*
348                          * Update the current buffer size with the new data.
349                          */
350
351                         if(pos + data_used > wcp->offset + wcp->data_size) {
352                                 wcp->data_size = pos + data_used - wcp->offset;
353                         }
354
355                         /*
356                          * Update the file size if changed.
357                          */
358
359                         if (wcp->offset + wcp->data_size > wcp->file_size) {
360                                 if (wcp_file_size_change(fsp) == -1) {
361                                         return -1;
362                                 }
363                         }
364
365                         /*
366                          * If we used all the data then
367                          * return here.
368                          */
369
370                         if(n == data_used) {
371                                 return n;
372                         } else {
373                                 cache_flush_needed = True;
374                         }
375                         /*
376                          * Move the start of data forward by the amount used,
377                          * cut down the amount left by the same amount.
378                          */
379
380                         data += data_used;
381                         pos += data_used;
382                         n -= data_used;
383
384                         DO_PROFILE_INC(writecache_abutted_writes);
385                         total_written = data_used;
386
387                         write_path = 1;
388
389                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) && 
390                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
391
392                         /* ASCII art.... JRA.
393
394                         +---------------+
395                         | Cache buffer  |
396                         +---------------+
397
398             +-------------------+
399             | Data to write     |
400             +-------------------+
401
402                         */
403
404                         /*
405                          * End of write overlaps the existing data.
406                          */
407
408                         size_t data_used = pos + n - wcp->offset;
409
410                         memcpy(wcp->data, data + n - data_used, data_used);
411
412                         /*
413                          * Update the current buffer size with the new data.
414                          */
415
416                         if(pos + n > wcp->offset + wcp->data_size) {
417                                 wcp->data_size = pos + n - 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                          * We don't need to move the start of data, but we
432                          * cut down the amount left by the amount used.
433                          */
434
435                         n -= data_used;
436
437                         /*
438                          * We cannot have used all the data here.
439                          */
440
441                         cache_flush_needed = True;
442
443                         DO_PROFILE_INC(writecache_abutted_writes);
444                         total_written = data_used;
445
446                         write_path = 2;
447
448                 } else if ( (pos >= wcp->file_size) && 
449                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
450                                         (pos > wcp->offset + wcp->data_size) && 
451                                         (pos < wcp->offset + wcp->alloc_size) ) {
452
453                         /* ASCII art.... JRA.
454
455                        End of file ---->|
456
457                         +---------------+---------------+
458                         | Cached data   | Cache buffer  |
459                         +---------------+---------------+
460
461                                               +-------------------+
462                                               | Data to write     |
463                                               +-------------------+
464
465                         */
466
467                         /*
468                          * Non-contiguous write part of which fits within
469                          * the cache buffer and is extending the file
470                          * and the cache contents reflect the current
471                          * data up to the current end of the file.
472                          */
473
474                         size_t data_used;
475
476                         if(pos + n <= wcp->offset + wcp->alloc_size) {
477                                 data_used = n;
478                         } else {
479                                 data_used = wcp->offset + wcp->alloc_size - pos;
480                         }
481
482                         /*
483                          * Fill in the non-continuous area with zeros.
484                          */
485
486                         memset(wcp->data + wcp->data_size, '\0',
487                                 pos - (wcp->offset + wcp->data_size) );
488
489                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
490
491                         /*
492                          * Update the current buffer size with the new data.
493                          */
494
495                         if(pos + data_used > wcp->offset + wcp->data_size) {
496                                 wcp->data_size = pos + data_used - wcp->offset;
497                         }
498
499                         /*
500                          * Update the file size if changed.
501                          */
502
503                         if (wcp->offset + wcp->data_size > wcp->file_size) {
504                                 if (wcp_file_size_change(fsp) == -1) {
505                                         return -1;
506                                 }
507                         }
508
509                         /*
510                          * If we used all the data then
511                          * return here.
512                          */
513
514                         if(n == data_used) {
515                                 return n;
516                         } else {
517                                 cache_flush_needed = True;
518                         }
519
520                         /*
521                          * Move the start of data forward by the amount used,
522                          * cut down the amount left by the same amount.
523                          */
524
525                         data += data_used;
526                         pos += data_used;
527                         n -= data_used;
528
529                         DO_PROFILE_INC(writecache_abutted_writes);
530                         total_written = data_used;
531
532                         write_path = 3;
533
534                 } else if ( (pos >= wcp->file_size) &&
535                             (n == 1) &&
536                             (wcp->file_size == wcp->offset + wcp->data_size) &&
537                             (pos < wcp->file_size + wcp->alloc_size)) {
538
539                         /*
540
541                 End of file ---->|
542
543                  +---------------+---------------+
544                  | Cached data   | Cache buffer  |
545                  +---------------+---------------+
546
547                                  |<------- allocated size ---------------->|
548
549                                                          +--------+
550                                                          | 1 Byte |
551                                                          +--------+
552
553                         MS-Office seems to do this a lot to determine if there's enough
554                         space on the filesystem to write a new file.
555
556                         Change to :
557
558                 End of file ---->|
559                                  +-----------------------+--------+
560                                  | Zeroed Cached data    | 1 Byte |
561                                  +-----------------------+--------+
562                         */
563
564                         flush_write_cache(fsp, WRITE_FLUSH);
565                         wcp->offset = wcp->file_size;
566                         wcp->data_size = pos - wcp->file_size + 1;
567                         memset(wcp->data, '\0', wcp->data_size);
568                         memcpy(wcp->data + wcp->data_size-1, data, 1);
569
570                         /*
571                          * Update the file size if changed.
572                          */
573
574                         if (wcp->offset + wcp->data_size > wcp->file_size) {
575                                 if (wcp_file_size_change(fsp) == -1) {
576                                         return -1;
577                                 }
578                         }
579
580                         return n;
581
582                 } else {
583
584                         /* ASCII art..... JRA.
585
586    Case 1).
587
588                         +---------------+---------------+
589                         | Cached data   | Cache buffer  |
590                         +---------------+---------------+
591
592                                                               +-------------------+
593                                                               | Data to write     |
594                                                               +-------------------+
595
596    Case 2).
597
598                            +---------------+---------------+
599                            | Cached data   | Cache buffer  |
600                            +---------------+---------------+
601
602    +-------------------+
603    | Data to write     |
604    +-------------------+
605
606     Case 3).
607
608                            +---------------+---------------+
609                            | Cached data   | Cache buffer  |
610                            +---------------+---------------+
611
612                   +-----------------------------------------------------+
613                   | Data to write                                       |
614                   +-----------------------------------------------------+
615
616                   */
617
618                         /*
619                          * Write is bigger than buffer, or there is no overlap on the
620                          * low or high ends.
621                          */
622
623                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
624 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
625
626                         /*
627                          * If write would fit in the cache, and is larger than
628                          * the data already in the cache, flush the cache and
629                          * preferentially copy the data new data into it. Otherwise
630                          * just write the data directly.
631                          */
632
633                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
634                                 cache_flush_needed = True;
635                         } else {
636                                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
637
638                                 /*
639                                  * If the write overlaps the entire cache, then
640                                  * discard the current contents of the cache.
641                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
642                                  */
643
644                                 if ((pos <= wcp->offset) &&
645                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
646                                         DEBUG(9,("write_file: discarding overwritten write \
647 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
648                                         wcp->data_size = 0;
649                                 }
650
651                                 DO_PROFILE_INC(writecache_direct_writes);
652                                 if (ret == -1) {
653                                         return ret;
654                                 }
655
656                                 if (pos + ret > wcp->file_size) {
657                                         wcp->file_size = pos + ret;
658                                 }
659
660                                 return ret;
661                         }
662
663                         write_path = 4;
664
665                 }
666
667                 if (cache_flush_needed) {
668                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
669 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
670                                 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
671                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
672
673                         flush_write_cache(fsp, WRITE_FLUSH);
674                 }
675         }
676
677         /*
678          * If the write request is bigger than the cache
679          * size, write it all out.
680          */
681
682         if (n > wcp->alloc_size ) {
683                 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
684                 if (ret == -1) {
685                         return -1;
686                 }
687
688                 if (pos + ret > wcp->file_size) {
689                         wcp->file_size = pos + n;
690                 }
691
692                 DO_PROFILE_INC(writecache_direct_writes);
693                 return total_written + n;
694         }
695
696         /*
697          * If there's any data left, cache it.
698          */
699
700         if (n) {
701 #ifdef WITH_PROFILE
702                 if (wcp->data_size) {
703                         DO_PROFILE_INC(writecache_abutted_writes);
704                 } else {
705                         DO_PROFILE_INC(writecache_init_writes);
706                 }
707 #endif
708                 memcpy(wcp->data+wcp->data_size, data, n);
709                 if (wcp->data_size == 0) {
710                         wcp->offset = pos;
711                         DO_PROFILE_INC(writecache_num_write_caches);
712                 }
713                 wcp->data_size += n;
714
715                 /*
716                  * Update the file size if changed.
717                  */
718
719                 if (wcp->offset + wcp->data_size > wcp->file_size) {
720                         if (wcp_file_size_change(fsp) == -1) {
721                                 return -1;
722                         }
723                 }
724                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
725                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
726
727                 total_written += n;
728                 return total_written; /* .... that's a write :) */
729         }
730   
731         return total_written;
732 }
733
734 /****************************************************************************
735  Delete the write cache structure.
736 ****************************************************************************/
737
738 void delete_write_cache(files_struct *fsp)
739 {
740         write_cache *wcp;
741
742         if(!fsp) {
743                 return;
744         }
745
746         if(!(wcp = fsp->wcp)) {
747                 return;
748         }
749
750         DO_PROFILE_DEC(writecache_allocated_write_caches);
751         allocated_write_caches--;
752
753         SMB_ASSERT(wcp->data_size == 0);
754
755         SAFE_FREE(wcp->data);
756         SAFE_FREE(fsp->wcp);
757
758         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
759 }
760
761 /****************************************************************************
762  Setup the write cache structure.
763 ****************************************************************************/
764
765 static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
766 {
767         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
768         write_cache *wcp;
769
770         if (allocated_write_caches >= MAX_WRITE_CACHES) {
771                 return False;
772         }
773
774         if(alloc_size == 0 || fsp->wcp) {
775                 return False;
776         }
777
778         if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
779                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
780                 return False;
781         }
782
783         wcp->file_size = file_size;
784         wcp->offset = 0;
785         wcp->alloc_size = alloc_size;
786         wcp->data_size = 0;
787         if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
788                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
789                         (unsigned int)wcp->alloc_size ));
790                 SAFE_FREE(wcp);
791                 return False;
792         }
793
794         memset(wcp->data, '\0', wcp->alloc_size );
795
796         fsp->wcp = wcp;
797         DO_PROFILE_INC(writecache_allocated_write_caches);
798         allocated_write_caches++;
799
800         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
801                 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
802
803         return True;
804 }
805
806 /****************************************************************************
807  Cope with a size change.
808 ****************************************************************************/
809
810 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
811 {
812         if(fsp->wcp) {
813                 /* The cache *must* have been flushed before we do this. */
814                 if (fsp->wcp->data_size != 0) {
815                         char *msg;
816                         asprintf(&msg, "set_filelen_write_cache: size change "
817                                  "on file %s with write cache size = %lu\n",
818                                  fsp->fsp_name,
819                                  (unsigned long)fsp->wcp->data_size);
820                         smb_panic(msg);
821                 }
822                 fsp->wcp->file_size = file_size;
823         }
824 }
825
826 /*******************************************************************
827  Flush a write cache struct to disk.
828 ********************************************************************/
829
830 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
831 {
832         write_cache *wcp = fsp->wcp;
833         size_t data_size;
834         ssize_t ret;
835
836         if(!wcp || !wcp->data_size) {
837                 return 0;
838         }
839
840         data_size = wcp->data_size;
841         wcp->data_size = 0;
842
843         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
844
845         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
846                 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
847
848 #ifdef WITH_PROFILE
849         if(data_size == wcp->alloc_size) {
850                 DO_PROFILE_INC(writecache_num_perfect_writes);
851         }
852 #endif
853
854         ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
855
856         /*
857          * Ensure file size if kept up to date if write extends file.
858          */
859
860         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
861                 wcp->file_size = wcp->offset + ret;
862         }
863
864         return ret;
865 }
866
867 /*******************************************************************
868 sync a file
869 ********************************************************************/
870
871 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
872 {
873         if (fsp->fh->fd == -1)
874                 return NT_STATUS_INVALID_HANDLE;
875
876         if (lp_strict_sync(SNUM(conn)) &&
877             (lp_syncalways(SNUM(conn)) || write_through)) {
878                 int ret = flush_write_cache(fsp, SYNC_FLUSH);
879                 if (ret == -1) {
880                         return map_nt_error_from_unix(errno);
881                 }
882                 ret = SMB_VFS_FSYNC(fsp);
883                 if (ret == -1) {
884                         return map_nt_error_from_unix(errno);
885                 }
886         }
887         return NT_STATUS_OK;
888 }
889
890 /************************************************************
891  Perform a stat whether a valid fd or not.
892 ************************************************************/
893
894 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
895 {
896         if (fsp->fh->fd == -1) {
897                 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
898         } else {
899                 return SMB_VFS_FSTAT(fsp, pst);
900         }
901 }