r23773: One pstring a day...
[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 2 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, write to the Free Software
20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23 #include "includes.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                 return -1;
61         }
62
63         /*
64          * Serve from write cache if we can.
65          */
66
67         if(read_from_write_cache(fsp, data, pos, n)) {
68                 fsp->fh->pos = pos + n;
69                 fsp->fh->position_information = fsp->fh->pos;
70                 return n;
71         }
72
73         flush_write_cache(fsp, READ_FLUSH);
74
75         fsp->fh->pos = pos;
76
77         if (n > 0) {
78 #ifdef DMF_FIX
79                 int numretries = 3;
80 tryagain:
81                 readret = SMB_VFS_PREAD(fsp,fsp->fh->fd,data,n,pos);
82
83                 if (readret == -1) {
84                         if ((errno == EAGAIN) && numretries) {
85                                 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
86                                 (void)sleep(10);
87                                 --numretries;
88                                 goto tryagain;
89                         }
90                         return -1;
91                 }
92 #else /* NO DMF fix. */
93                 readret = SMB_VFS_PREAD(fsp,fsp->fh->fd,data,n,pos);
94
95                 if (readret == -1) {
96                         return -1;
97                 }
98 #endif
99                 if (readret > 0) {
100                         ret += readret;
101                 }
102         }
103
104         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
105                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
106
107         fsp->fh->pos += ret;
108         fsp->fh->position_information = fsp->fh->pos;
109
110         return(ret);
111 }
112
113 /* how many write cache buffers have been allocated */
114 static unsigned int allocated_write_caches;
115
116 /****************************************************************************
117  *Really* write to a file.
118 ****************************************************************************/
119
120 static ssize_t real_write_file(files_struct *fsp,const char *data, SMB_OFF_T pos, size_t n)
121 {
122         ssize_t ret;
123
124         if (pos == -1) {
125                 ret = vfs_write_data(fsp, data, n);
126         } else {
127                 fsp->fh->pos = pos;
128                 if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
129                         if (vfs_fill_sparse(fsp, pos) == -1) {
130                                 return -1;
131                         }
132                 }
133                 ret = vfs_pwrite_data(fsp, data, n, pos);
134         }
135
136         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
137                 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
138
139         if (ret != -1) {
140                 fsp->fh->pos += ret;
141
142                 /*
143                  * It turns out that setting the last write time from a Windows
144                  * client stops any subsequent writes from updating the write time.
145                  * Doing this after the write gives a race condition here where
146                  * a stat may see the changed write time before we reset it here,
147                  * but it's cheaper than having to store the write time in shared
148                  * memory and look it up using dev/inode across all running smbd's.
149                  * The 99% solution will hopefully be good enough in this case. JRA.
150                  */
151
152                 if (!null_timespec(fsp->pending_modtime)) {
153                         set_filetime(fsp->conn, fsp->fsp_name, fsp->pending_modtime);
154
155                         /* If we didn't get the "set modtime" call ourselves, we must
156                            store the last write time to restore on close. JRA. */
157                         if (!fsp->pending_modtime_owner) {
158                                 fsp->last_write_time = timespec_current();
159                         }
160                 }
161
162 /* Yes - this is correct - writes don't update this. JRA. */
163 /* Found by Samba4 tests. */
164 #if 0
165                 fsp->position_information = fsp->pos;
166 #endif
167         }
168
169         return ret;
170 }
171
172 /****************************************************************************
173  File size cache change.
174  Updates size on disk but doesn't flush the cache.
175 ****************************************************************************/
176
177 static int wcp_file_size_change(files_struct *fsp)
178 {
179         int ret;
180         write_cache *wcp = fsp->wcp;
181
182         wcp->file_size = wcp->offset + wcp->data_size;
183         ret = SMB_VFS_FTRUNCATE(fsp, fsp->fh->fd, wcp->file_size);
184         if (ret == -1) {
185                 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f error %s\n",
186                         fsp->fsp_name, (double)wcp->file_size, strerror(errno) ));
187         }
188         return ret;
189 }
190
191 /****************************************************************************
192  Write to a file.
193 ****************************************************************************/
194
195 ssize_t write_file(files_struct *fsp, const char *data, SMB_OFF_T pos, size_t n)
196 {
197         write_cache *wcp = fsp->wcp;
198         ssize_t total_written = 0;
199         int write_path = -1; 
200
201         if (fsp->print_file) {
202                 fstring sharename;
203                 uint32 jobid;
204
205                 if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
206                         DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
207                                                 (unsigned int)fsp->rap_print_jobid ));
208                         errno = EBADF;
209                         return -1;
210                 }
211
212                 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
213         }
214
215         if (!fsp->can_write) {
216                 errno = EPERM;
217                 return -1;
218         }
219
220         if (!fsp->modified) {
221                 SMB_STRUCT_STAT st;
222                 fsp->modified = True;
223
224                 if (SMB_VFS_FSTAT(fsp,fsp->fh->fd,&st) == 0) {
225                         int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
226                         if ((lp_store_dos_attributes(SNUM(fsp->conn)) || MAP_ARCHIVE(fsp->conn)) && !IS_DOS_ARCHIVE(dosmode)) {
227                                 file_set_dosmode(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st, False);
228                         }
229
230                         /*
231                          * If this is the first write and we have an exclusive oplock then setup
232                          * the write cache.
233                          */
234
235                         if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
236                                 setup_write_cache(fsp, st.st_size);
237                                 wcp = fsp->wcp;
238                         } 
239                 }  
240         }
241
242 #ifdef WITH_PROFILE
243         DO_PROFILE_INC(writecache_total_writes);
244         if (!fsp->oplock_type) {
245                 DO_PROFILE_INC(writecache_non_oplock_writes);
246         }
247 #endif
248
249         /*
250          * If this file is level II oplocked then we need
251          * to grab the shared memory lock and inform all
252          * other files with a level II lock that they need
253          * to flush their read caches. We keep the lock over
254          * the shared memory area whilst doing this.
255          */
256
257         release_level_2_oplocks_on_change(fsp);
258
259 #ifdef WITH_PROFILE
260         if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
261                 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
262 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
263                         profile_p->writecache_init_writes,
264                         profile_p->writecache_abutted_writes,
265                         profile_p->writecache_total_writes,
266                         profile_p->writecache_non_oplock_writes,
267                         profile_p->writecache_allocated_write_caches,
268                         profile_p->writecache_num_write_caches,
269                         profile_p->writecache_direct_writes,
270                         profile_p->writecache_num_perfect_writes,
271                         profile_p->writecache_read_hits ));
272
273                 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
274                         profile_p->writecache_flushed_writes[SEEK_FLUSH],
275                         profile_p->writecache_flushed_writes[READ_FLUSH],
276                         profile_p->writecache_flushed_writes[WRITE_FLUSH],
277                         profile_p->writecache_flushed_writes[READRAW_FLUSH],
278                         profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
279                         profile_p->writecache_flushed_writes[CLOSE_FLUSH],
280                         profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
281         }
282 #endif
283
284         if(!wcp) {
285                 DO_PROFILE_INC(writecache_direct_writes);
286                 total_written = real_write_file(fsp, data, pos, n);
287                 return total_written;
288         }
289
290         DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
291                 fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
292
293         fsp->fh->pos = pos + n;
294
295         /* 
296          * If we have active cache and it isn't contiguous then we flush.
297          * NOTE: There is a small problem with running out of disk ....
298          */
299
300         if (wcp->data_size) {
301                 BOOL cache_flush_needed = False;
302
303                 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
304       
305                         /* ASCII art.... JRA.
306
307       +--------------+-----
308       | Cached data  | Rest of allocated cache buffer....
309       +--------------+-----
310
311             +-------------------+
312             | Data to write     |
313             +-------------------+
314
315                         */
316
317                         /*
318                          * Start of write overlaps or abutts the existing data.
319                          */
320
321                         size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
322
323                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
324
325                         /*
326                          * Update the current buffer size with the new data.
327                          */
328
329                         if(pos + data_used > wcp->offset + wcp->data_size) {
330                                 wcp->data_size = pos + data_used - wcp->offset;
331                         }
332
333                         /*
334                          * Update the file size if changed.
335                          */
336
337                         if (wcp->offset + wcp->data_size > wcp->file_size) {
338                                 if (wcp_file_size_change(fsp) == -1) {
339                                         return -1;
340                                 }
341                         }
342
343                         /*
344                          * If we used all the data then
345                          * return here.
346                          */
347
348                         if(n == data_used) {
349                                 return n;
350                         } else {
351                                 cache_flush_needed = True;
352                         }
353                         /*
354                          * Move the start of data forward by the amount used,
355                          * cut down the amount left by the same amount.
356                          */
357
358                         data += data_used;
359                         pos += data_used;
360                         n -= data_used;
361
362                         DO_PROFILE_INC(writecache_abutted_writes);
363                         total_written = data_used;
364
365                         write_path = 1;
366
367                 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) && 
368                                         (pos + n <= wcp->offset + wcp->alloc_size)) {
369
370                         /* ASCII art.... JRA.
371
372                         +---------------+
373                         | Cache buffer  |
374                         +---------------+
375
376             +-------------------+
377             | Data to write     |
378             +-------------------+
379
380                         */
381
382                         /*
383                          * End of write overlaps the existing data.
384                          */
385
386                         size_t data_used = pos + n - wcp->offset;
387
388                         memcpy(wcp->data, data + n - data_used, data_used);
389
390                         /*
391                          * Update the current buffer size with the new data.
392                          */
393
394                         if(pos + n > wcp->offset + wcp->data_size) {
395                                 wcp->data_size = pos + n - wcp->offset;
396                         }
397
398                         /*
399                          * Update the file size if changed.
400                          */
401
402                         if (wcp->offset + wcp->data_size > wcp->file_size) {
403                                 if (wcp_file_size_change(fsp) == -1) {
404                                         return -1;
405                                 }
406                         }
407
408                         /*
409                          * We don't need to move the start of data, but we
410                          * cut down the amount left by the amount used.
411                          */
412
413                         n -= data_used;
414
415                         /*
416                          * We cannot have used all the data here.
417                          */
418
419                         cache_flush_needed = True;
420
421                         DO_PROFILE_INC(writecache_abutted_writes);
422                         total_written = data_used;
423
424                         write_path = 2;
425
426                 } else if ( (pos >= wcp->file_size) && 
427                                         (wcp->offset + wcp->data_size == wcp->file_size) &&
428                                         (pos > wcp->offset + wcp->data_size) && 
429                                         (pos < wcp->offset + wcp->alloc_size) ) {
430
431                         /* ASCII art.... JRA.
432
433                        End of file ---->|
434
435                         +---------------+---------------+
436                         | Cached data   | Cache buffer  |
437                         +---------------+---------------+
438
439                                               +-------------------+
440                                               | Data to write     |
441                                               +-------------------+
442
443                         */
444
445                         /*
446                          * Non-contiguous write part of which fits within
447                          * the cache buffer and is extending the file
448                          * and the cache contents reflect the current
449                          * data up to the current end of the file.
450                          */
451
452                         size_t data_used;
453
454                         if(pos + n <= wcp->offset + wcp->alloc_size) {
455                                 data_used = n;
456                         } else {
457                                 data_used = wcp->offset + wcp->alloc_size - pos;
458                         }
459
460                         /*
461                          * Fill in the non-continuous area with zeros.
462                          */
463
464                         memset(wcp->data + wcp->data_size, '\0',
465                                 pos - (wcp->offset + wcp->data_size) );
466
467                         memcpy(wcp->data + (pos - wcp->offset), data, data_used);
468
469                         /*
470                          * Update the current buffer size with the new data.
471                          */
472
473                         if(pos + data_used > wcp->offset + wcp->data_size) {
474                                 wcp->data_size = pos + data_used - wcp->offset;
475                         }
476
477                         /*
478                          * Update the file size if changed.
479                          */
480
481                         if (wcp->offset + wcp->data_size > wcp->file_size) {
482                                 if (wcp_file_size_change(fsp) == -1) {
483                                         return -1;
484                                 }
485                         }
486
487                         /*
488                          * If we used all the data then
489                          * return here.
490                          */
491
492                         if(n == data_used) {
493                                 return n;
494                         } else {
495                                 cache_flush_needed = True;
496                         }
497
498                         /*
499                          * Move the start of data forward by the amount used,
500                          * cut down the amount left by the same amount.
501                          */
502
503                         data += data_used;
504                         pos += data_used;
505                         n -= data_used;
506
507                         DO_PROFILE_INC(writecache_abutted_writes);
508                         total_written = data_used;
509
510                         write_path = 3;
511
512                 } else if ( (pos >= wcp->file_size) && 
513                             (n == 1) &&
514                             (pos < wcp->offset + 2*wcp->alloc_size) &&
515                             (wcp->file_size == wcp->offset + wcp->data_size)) {
516
517                         /*
518                         +---------------+
519                         | Cached data   |
520                         +---------------+
521
522                                                          +--------+
523                                                          | 1 Byte |
524                                                          +--------+
525
526                         MS-Office seems to do this a lot to determine if there's enough
527                         space on the filesystem to write a new file.
528                         */
529
530                         SMB_BIG_UINT new_start = wcp->offset + wcp->data_size;
531
532                         flush_write_cache(fsp, WRITE_FLUSH);
533                         wcp->offset = new_start;
534                         wcp->data_size = pos - new_start + 1;
535                         memset(wcp->data, '\0', wcp->data_size);
536                         memcpy(wcp->data + wcp->data_size-1, data, 1);
537
538                         /*
539                          * Update the file size if changed.
540                          */
541
542                         if (wcp->offset + wcp->data_size > wcp->file_size) {
543                                 if (wcp_file_size_change(fsp) == -1) {
544                                         return -1;
545                                 }
546                         }
547
548                         return n;
549
550                 } else {
551
552                         /* ASCII art..... JRA.
553
554    Case 1).
555
556                         +---------------+---------------+
557                         | Cached data   | Cache buffer  |
558                         +---------------+---------------+
559
560                                                               +-------------------+
561                                                               | Data to write     |
562                                                               +-------------------+
563
564    Case 2).
565
566                            +---------------+---------------+
567                            | Cached data   | Cache buffer  |
568                            +---------------+---------------+
569
570    +-------------------+
571    | Data to write     |
572    +-------------------+
573
574     Case 3).
575
576                            +---------------+---------------+
577                            | Cached data   | Cache buffer  |
578                            +---------------+---------------+
579
580                   +-----------------------------------------------------+
581                   | Data to write                                       |
582                   +-----------------------------------------------------+
583
584                   */
585
586                         /*
587                          * Write is bigger than buffer, or there is no overlap on the
588                          * low or high ends.
589                          */
590
591                         DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
592 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
593
594                         /*
595                          * If write would fit in the cache, and is larger than
596                          * the data already in the cache, flush the cache and
597                          * preferentially copy the data new data into it. Otherwise
598                          * just write the data directly.
599                          */
600
601                         if ( n <= wcp->alloc_size && n > wcp->data_size) {
602                                 cache_flush_needed = True;
603                         } else {
604                                 ssize_t ret = real_write_file(fsp, data, pos, n);
605
606                                 /*
607                                  * If the write overlaps the entire cache, then
608                                  * discard the current contents of the cache.
609                                  * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
610                                  */
611
612                                 if ((pos <= wcp->offset) &&
613                                                 (pos + n >= wcp->offset + wcp->data_size) ) {
614                                         DEBUG(9,("write_file: discarding overwritten write \
615 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
616                                         wcp->data_size = 0;
617                                 }
618
619                                 DO_PROFILE_INC(writecache_direct_writes);
620                                 if (ret == -1) {
621                                         return ret;
622                                 }
623
624                                 if (pos + ret > wcp->file_size) {
625                                         wcp->file_size = pos + ret;
626                                 }
627
628                                 return ret;
629                         }
630
631                         write_path = 4;
632
633                 }
634
635                 if (cache_flush_needed) {
636                         DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
637 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
638                                 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
639                                 (double)wcp->offset, (unsigned int)wcp->data_size ));
640
641                         flush_write_cache(fsp, WRITE_FLUSH);
642                 }
643         }
644
645         /*
646          * If the write request is bigger than the cache
647          * size, write it all out.
648          */
649
650         if (n > wcp->alloc_size ) {
651                 ssize_t ret = real_write_file(fsp, data, pos, n);
652                 if (ret == -1) {
653                         return -1;
654                 }
655
656                 if (pos + ret > wcp->file_size) {
657                         wcp->file_size = pos + n;
658                 }
659
660                 DO_PROFILE_INC(writecache_direct_writes);
661                 return total_written + n;
662         }
663
664         /*
665          * If there's any data left, cache it.
666          */
667
668         if (n) {
669 #ifdef WITH_PROFILE
670                 if (wcp->data_size) {
671                         DO_PROFILE_INC(writecache_abutted_writes);
672                 } else {
673                         DO_PROFILE_INC(writecache_init_writes);
674                 }
675 #endif
676                 memcpy(wcp->data+wcp->data_size, data, n);
677                 if (wcp->data_size == 0) {
678                         wcp->offset = pos;
679                         DO_PROFILE_INC(writecache_num_write_caches);
680                 }
681                 wcp->data_size += n;
682
683                 /*
684                  * Update the file size if changed.
685                  */
686
687                 if (wcp->offset + wcp->data_size > wcp->file_size) {
688                         if (wcp_file_size_change(fsp) == -1) {
689                                 return -1;
690                         }
691                 }
692                 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
693                         (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
694
695                 total_written += n;
696                 return total_written; /* .... that's a write :) */
697         }
698   
699         return total_written;
700 }
701
702 /****************************************************************************
703  Delete the write cache structure.
704 ****************************************************************************/
705
706 void delete_write_cache(files_struct *fsp)
707 {
708         write_cache *wcp;
709
710         if(!fsp) {
711                 return;
712         }
713
714         if(!(wcp = fsp->wcp)) {
715                 return;
716         }
717
718         DO_PROFILE_DEC(writecache_allocated_write_caches);
719         allocated_write_caches--;
720
721         SMB_ASSERT(wcp->data_size == 0);
722
723         SAFE_FREE(wcp->data);
724         SAFE_FREE(fsp->wcp);
725
726         DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
727 }
728
729 /****************************************************************************
730  Setup the write cache structure.
731 ****************************************************************************/
732
733 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
734 {
735         ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
736         write_cache *wcp;
737
738         if (allocated_write_caches >= MAX_WRITE_CACHES) {
739                 return False;
740         }
741
742         if(alloc_size == 0 || fsp->wcp) {
743                 return False;
744         }
745
746         if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
747                 DEBUG(0,("setup_write_cache: malloc fail.\n"));
748                 return False;
749         }
750
751         wcp->file_size = file_size;
752         wcp->offset = 0;
753         wcp->alloc_size = alloc_size;
754         wcp->data_size = 0;
755         if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
756                 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
757                         (unsigned int)wcp->alloc_size ));
758                 SAFE_FREE(wcp);
759                 return False;
760         }
761
762         memset(wcp->data, '\0', wcp->alloc_size );
763
764         fsp->wcp = wcp;
765         DO_PROFILE_INC(writecache_allocated_write_caches);
766         allocated_write_caches++;
767
768         DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
769                 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
770
771         return True;
772 }
773
774 /****************************************************************************
775  Cope with a size change.
776 ****************************************************************************/
777
778 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
779 {
780         if(fsp->wcp) {
781                 /* The cache *must* have been flushed before we do this. */
782                 if (fsp->wcp->data_size != 0) {
783                         char *msg;
784                         asprintf(&msg, "set_filelen_write_cache: size change "
785                                  "on file %s with write cache size = %lu\n",
786                                  fsp->fsp_name,
787                                  (unsigned long)fsp->wcp->data_size);
788                         smb_panic(msg);
789                 }
790                 fsp->wcp->file_size = file_size;
791         }
792 }
793
794 /*******************************************************************
795  Flush a write cache struct to disk.
796 ********************************************************************/
797
798 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
799 {
800         write_cache *wcp = fsp->wcp;
801         size_t data_size;
802         ssize_t ret;
803
804         if(!wcp || !wcp->data_size) {
805                 return 0;
806         }
807
808         data_size = wcp->data_size;
809         wcp->data_size = 0;
810
811         DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
812
813         DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
814                 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
815
816 #ifdef WITH_PROFILE
817         if(data_size == wcp->alloc_size) {
818                 DO_PROFILE_INC(writecache_num_perfect_writes);
819         }
820 #endif
821
822         ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
823
824         /*
825          * Ensure file size if kept up to date if write extends file.
826          */
827
828         if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
829                 wcp->file_size = wcp->offset + ret;
830         }
831
832         return ret;
833 }
834
835 /*******************************************************************
836 sync a file
837 ********************************************************************/
838
839 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, BOOL write_through)
840 {
841         if (fsp->fh->fd == -1)
842                 return NT_STATUS_INVALID_HANDLE;
843
844         if (lp_strict_sync(SNUM(conn)) &&
845             (lp_syncalways(SNUM(conn)) || write_through)) {
846                 int ret = flush_write_cache(fsp, SYNC_FLUSH);
847                 if (ret == -1) {
848                         return map_nt_error_from_unix(errno);
849                 }
850                 ret = SMB_VFS_FSYNC(fsp,fsp->fh->fd);
851                 if (ret == -1) {
852                         return map_nt_error_from_unix(errno);
853                 }
854         }
855         return NT_STATUS_OK;
856 }
857
858 /************************************************************
859  Perform a stat whether a valid fd or not.
860 ************************************************************/
861
862 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
863 {
864         if (fsp->fh->fd == -1) {
865                 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
866         } else {
867                 return SMB_VFS_FSTAT(fsp,fsp->fh->fd, pst);
868         }
869 }