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must add one to the extra_data size to transfer the 0 string terminator.
[Samba/gebeck_regimport.git] / source3 / smbd / fileio.c
blobd5df9826dfd09cb6f8a62c3d0073e77777b74488
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 Seek a file. Try to avoid the seek if possible.
29 ****************************************************************************/
30
31 static SMB_OFF_T seek_file(files_struct *fsp,SMB_OFF_T pos)
32 {
33 SMB_OFF_T offset = 0;
34 SMB_OFF_T seek_ret;
35
36 if (fsp->print_file && lp_postscript(fsp->conn->service))
37 offset = 3;
38
39 seek_ret = fsp->conn->vfs_ops.lseek(fsp,fsp->fd,pos+offset,SEEK_SET);
40
41 if(seek_ret == -1) {
42 DEBUG(0,("seek_file: (%s) sys_lseek failed. Error was %s\n",
43 fsp->fsp_name, strerror(errno) ));
44 fsp->pos = -1;
45 return -1;
46 }
47
48 fsp->pos = seek_ret - offset;
49
50 DEBUG(10,("seek_file (%s): requested pos = %.0f, new pos = %.0f\n",
51 fsp->fsp_name, (double)(pos+offset), (double)fsp->pos ));
52
53 return(fsp->pos);
54 }
55
56 /****************************************************************************
57 Read from write cache if we can.
58 ****************************************************************************/
59
60
61 static BOOL read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
62 {
63 write_cache *wcp = fsp->wcp;
64
65 if(!wcp)
66 return False;
67
68 if(n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size)
69 return False;
70
71 memcpy(data, wcp->data + (pos - wcp->offset), n);
72
73 DO_PROFILE_INC(writecache_read_hits);
74
75 return True;
76 }
77
78 /****************************************************************************
79 Read from a file.
80 ****************************************************************************/
81
82 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
83 {
84 ssize_t ret=0,readret;
85
86 /* you can't read from print files */
87 if (fsp->print_file)
88 return -1;
89
90 /*
91 * Serve from write cache if we can.
92 */
93
94 if(read_from_write_cache(fsp, data, pos, n))
95 return n;
96
97 flush_write_cache(fsp, READ_FLUSH);
98
99 if (seek_file(fsp,pos) == -1) {
100 DEBUG(3,("read_file: Failed to seek to %.0f\n",(double)pos));
101 return(ret);
102 }
103
104 if (n > 0) {
105 #ifdef DMF_FIX
106 int numretries = 3;
107 tryagain:
108 readret = fsp->conn->vfs_ops.read(fsp,fsp->fd,data,n);
109 if (readret == -1) {
110 if ((errno == EAGAIN) && numretries) {
111 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
112 (void)sleep(10);
113 --numretries;
114 goto tryagain;
115 }
116 return -1;
117 }
118 #else /* NO DMF fix. */
119 readret = fsp->conn->vfs_ops.read(fsp,fsp->fd,data,n);
120 if (readret == -1)
121 return -1;
122 #endif
123 if (readret > 0)
124 ret += readret;
125 }
126
127 DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
128 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
129
130 return(ret);
131 }
132
133 /* how many write cache buffers have been allocated */
134 static unsigned int allocated_write_caches;
135
136 /****************************************************************************
137 *Really* write to a file.
138 ****************************************************************************/
139
140 static ssize_t real_write_file(files_struct *fsp,char *data,SMB_OFF_T pos, size_t n)
141 {
142 ssize_t ret;
143
144 if ((pos != -1) && (seek_file(fsp,pos) == -1))
145 return -1;
146
147 ret = vfs_write_data(fsp,data,n);
148
149 DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
150 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
151
152 return ret;
153 }
154
155 /****************************************************************************
156 write to a file
157 ****************************************************************************/
158
159 ssize_t write_file(files_struct *fsp, char *data, SMB_OFF_T pos, size_t n)
160 {
161 write_cache *wcp = fsp->wcp;
162 ssize_t total_written = 0;
163 int write_path = -1;
164
165 if (fsp->print_file)
166 return print_job_write(SNUM(fsp->conn), fsp->print_jobid, data, n);
167
168 if (!fsp->can_write) {
169 errno = EPERM;
170 return(0);
171 }
172
173 if (!fsp->modified) {
174 SMB_STRUCT_STAT st;
175 fsp->modified = True;
176
177 if (fsp->conn->vfs_ops.fstat(fsp,fsp->fd,&st) == 0) {
178 int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
179 fsp->size = st.st_size;
180 if (MAP_ARCHIVE(fsp->conn) && !IS_DOS_ARCHIVE(dosmode))
181 file_chmod(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st);
182
183 /*
184 * If this is the first write and we have an exclusive oplock then setup
185 * the write cache.
186 */
187
188 if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
189 setup_write_cache(fsp, st.st_size);
190 wcp = fsp->wcp;
191 }
192 }
193 }
194
195 #ifdef WITH_PROFILE
196 DO_PROFILE_INC(writecache_total_writes);
197 if (!fsp->oplock_type) {
198 DO_PROFILE_INC(writecache_non_oplock_writes);
199 }
200 #endif
201
202 /*
203 * If this file is level II oplocked then we need
204 * to grab the shared memory lock and inform all
205 * other files with a level II lock that they need
206 * to flush their read caches. We keep the lock over
207 * the shared memory area whilst doing this.
208 */
209
210 release_level_2_oplocks_on_change(fsp);
211
212 #ifdef WITH_PROFILE
213 if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
214 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
215 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
216 profile_p->writecache_init_writes,
217 profile_p->writecache_abutted_writes,
218 profile_p->writecache_total_writes,
219 profile_p->writecache_non_oplock_writes,
220 profile_p->writecache_allocated_write_caches,
221 profile_p->writecache_num_write_caches,
222 profile_p->writecache_direct_writes,
223 profile_p->writecache_num_perfect_writes,
224 profile_p->writecache_read_hits ));
225
226 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
227 profile_p->writecache_flushed_writes[SEEK_FLUSH],
228 profile_p->writecache_flushed_writes[READ_FLUSH],
229 profile_p->writecache_flushed_writes[WRITE_FLUSH],
230 profile_p->writecache_flushed_writes[READRAW_FLUSH],
231 profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
232 profile_p->writecache_flushed_writes[CLOSE_FLUSH],
233 profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
234 }
235 #endif
236
237 if(!wcp) {
238 DO_PROFILE_INC(writecache_direct_writes);
239 total_written = real_write_file(fsp, data, pos, n);
240 if ((total_written != -1) && (pos + total_written > fsp->size))
241 fsp->size = pos + total_written;
242 return total_written;
243 }
244
245 DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
246 fsp->fsp_name, fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
247
248 /*
249 * If we have active cache and it isn't contiguous then we flush.
250 * NOTE: There is a small problem with running out of disk ....
251 */
252
253 if (wcp->data_size) {
254
255 BOOL cache_flush_needed = False;
256
257 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
258
259 /* ASCII art.... JRA.
260
261 +--------------+-----
262 | Cached data | Rest of allocated cache buffer....
263 +--------------+-----
264
265 +-------------------+
266 | Data to write |
267 +-------------------+
268
269 */
270
271 /*
272 * Start of write overlaps or abutts the existing data.
273 */
274
275 size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
276
277 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
278
279 /*
280 * Update the current buffer size with the new data.
281 */
282
283 if(pos + data_used > wcp->offset + wcp->data_size)
284 wcp->data_size = pos + data_used - wcp->offset;
285
286 /*
287 * Update the file size if changed.
288 */
289
290 if (wcp->offset + wcp->data_size > wcp->file_size)
291 fsp->size = wcp->file_size = wcp->offset + wcp->data_size;
292
293 /*
294 * If we used all the data then
295 * return here.
296 */
297
298 if(n == data_used)
299 return n;
300 else
301 cache_flush_needed = True;
302
303 /*
304 * Move the start of data forward by the amount used,
305 * cut down the amount left by the same amount.
306 */
307
308 data += data_used;
309 pos += data_used;
310 n -= data_used;
311
312 DO_PROFILE_INC(writecache_abutted_writes);
313 total_written = data_used;
314
315 write_path = 1;
316
317 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
318 (pos + n <= wcp->offset + wcp->alloc_size)) {
319
320 /* ASCII art.... JRA.
321
322 +---------------+
323 | Cache buffer |
324 +---------------+
325
326 +-------------------+
327 | Data to write |
328 +-------------------+
329
330 */
331
332 /*
333 * End of write overlaps the existing data.
334 */
335
336 size_t data_used = pos + n - wcp->offset;
337
338 memcpy(wcp->data, data + n - data_used, data_used);
339
340 /*
341 * Update the current buffer size with the new data.
342 */
343
344 if(pos + n > wcp->offset + wcp->data_size)
345 wcp->data_size = pos + n - wcp->offset;
346
347 /*
348 * Update the file size if changed.
349 */
350
351 if (wcp->offset + wcp->data_size > wcp->file_size)
352 fsp->size = wcp->file_size = wcp->offset + wcp->data_size;
353
354 /*
355 * We don't need to move the start of data, but we
356 * cut down the amount left by the amount used.
357 */
358
359 n -= data_used;
360
361 /*
362 * We cannot have used all the data here.
363 */
364
365 cache_flush_needed = True;
366
367 DO_PROFILE_INC(writecache_abutted_writes);
368 total_written = data_used;
369
370 write_path = 2;
371
372 } else if ( (pos >= wcp->file_size) &&
373 (wcp->offset + wcp->data_size == wcp->file_size) &&
374 (pos > wcp->offset + wcp->data_size) &&
375 (pos < wcp->offset + wcp->alloc_size) ) {
376
377 /* ASCII art.... JRA.
378
379 End of file ---->|
380
381 +---------------+---------------+
382 | Cached data | Cache buffer |
383 +---------------+---------------+
384
385 +-------------------+
386 | Data to write |
387 +-------------------+
388
389 */
390
391 /*
392 * Non-contiguous write part of which fits within
393 * the cache buffer and is extending the file
394 * and the cache contents reflect the current
395 * data up to the current end of the file.
396 */
397
398 size_t data_used;
399
400 if(pos + n <= wcp->offset + wcp->alloc_size)
401 data_used = n;
402 else
403 data_used = wcp->offset + wcp->alloc_size - pos;
404
405 /*
406 * Fill in the non-continuous area with zeros.
407 */
408
409 memset(wcp->data + wcp->data_size, '\0',
410 pos - (wcp->offset + wcp->data_size) );
411
412 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
413
414 /*
415 * Update the current buffer size with the new data.
416 */
417
418 if(pos + data_used > wcp->offset + wcp->data_size)
419 wcp->data_size = pos + data_used - wcp->offset;
420
421 /*
422 * Update the file size if changed.
423 */
424
425 if (wcp->offset + wcp->data_size > wcp->file_size)
426 fsp->size = wcp->file_size = wcp->offset + wcp->data_size;
427
428 /*
429 * If we used all the data then
430 * return here.
431 */
432
433 if(n == data_used)
434 return n;
435 else
436 cache_flush_needed = True;
437
438 /*
439 * Move the start of data forward by the amount used,
440 * cut down the amount left by the same amount.
441 */
442
443 data += data_used;
444 pos += data_used;
445 n -= data_used;
446
447 DO_PROFILE_INC(writecache_abutted_writes);
448 total_written = data_used;
449
450 write_path = 3;
451
452 } else {
453
454 /* ASCII art..... JRA.
455
456 Case 1).
457
458 +---------------+---------------+
459 | Cached data | Cache buffer |
460 +---------------+---------------+
461
462 +-------------------+
463 | Data to write |
464 +-------------------+
465
466 Case 2).
467
468 +---------------+---------------+
469 | Cached data | Cache buffer |
470 +---------------+---------------+
471
472 +-------------------+
473 | Data to write |
474 +-------------------+
475
476 Case 3).
477
478 +---------------+---------------+
479 | Cached data | Cache buffer |
480 +---------------+---------------+
481
482 +-----------------------------------------------------+
483 | Data to write |
484 +-----------------------------------------------------+
485
486 */
487
488 /*
489 * Write is bigger than buffer, or there is no overlap on the
490 * low or high ends.
491 */
492
493 DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
494 len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
495
496 /*
497 * Update the file size if needed.
498 */
499
500 if(pos + n > wcp->file_size)
501 fsp->size = wcp->file_size = pos + n;
502
503 /*
504 * If write would fit in the cache, and is larger than
505 * the data already in the cache, flush the cache and
506 * preferentially copy the data new data into it. Otherwise
507 * just write the data directly.
508 */
509
510 if ( n <= wcp->alloc_size && n > wcp->data_size) {
511 cache_flush_needed = True;
512 } else {
513 ssize_t ret = real_write_file(fsp, data, pos, n);
514
515 /*
516 * If the write overlaps the entire cache, then
517 * discard the current contents of the cache.
518 * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
519 */
520
521 if ((pos <= wcp->offset) &&
522 (pos + n >= wcp->offset + wcp->data_size) ) {
523 DEBUG(9,("write_file: discarding overwritten write \
524 cache: fd = %d, off=%.0f, size=%u\n", fsp->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
525 wcp->data_size = 0;
526 }
527
528 DO_PROFILE_INC(writecache_direct_writes);
529 if (ret == -1)
530 return ret;
531
532 if (pos + ret > wcp->file_size)
533 fsp->size = wcp->file_size = pos + ret;
534
535 return ret;
536 }
537
538 write_path = 4;
539
540 }
541
542 if(wcp->data_size > wcp->file_size)
543 fsp->size = wcp->file_size = wcp->data_size;
544
545 if (cache_flush_needed) {
546 DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
547 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
548 write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
549 (double)wcp->offset, (unsigned int)wcp->data_size ));
550
551 flush_write_cache(fsp, WRITE_FLUSH);
552 }
553 }
554
555 /*
556 * If the write request is bigger than the cache
557 * size, write it all out.
558 */
559
560 if (n > wcp->alloc_size ) {
561 ssize_t ret = real_write_file(fsp, data, pos, n);
562 if (ret == -1)
563 return -1;
564
565 if (pos + ret > wcp->file_size)
566 fsp->size = wcp->file_size = pos + n;
567
568 DO_PROFILE_INC(writecache_direct_writes);
569 return total_written + n;
570 }
571
572 /*
573 * If there's any data left, cache it.
574 */
575
576 if (n) {
577 #ifdef WITH_PROFILE
578 if (wcp->data_size) {
579 DO_PROFILE_INC(writecache_abutted_writes);
580 } else {
581 DO_PROFILE_INC(writecache_init_writes);
582 }
583 #endif
584 memcpy(wcp->data+wcp->data_size, data, n);
585 if (wcp->data_size == 0) {
586 wcp->offset = pos;
587 DO_PROFILE_INC(writecache_num_write_caches);
588 }
589 wcp->data_size += n;
590
591 /*
592 * Update the file size if changed.
593 */
594
595 if (wcp->offset + wcp->data_size > wcp->file_size)
596 fsp->size = wcp->file_size = wcp->offset + wcp->data_size;
597 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
598 (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
599
600 total_written += n;
601 return total_written; /* .... that's a write :) */
602 }
603
604 return total_written;
605 }
606
607 /****************************************************************************
608 Delete the write cache structure.
609 ****************************************************************************/
610
611 void delete_write_cache(files_struct *fsp)
612 {
613 write_cache *wcp;
614
615 if(!fsp)
616 return;
617
618 if(!(wcp = fsp->wcp))
619 return;
620
621 DO_PROFILE_DEC(writecache_allocated_write_caches);
622 allocated_write_caches--;
623
624 SMB_ASSERT(wcp->data_size == 0);
625
626 SAFE_FREE(wcp->data);
627 SAFE_FREE(fsp->wcp);
628
629 DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
630 }
631
632 /****************************************************************************
633 Setup the write cache structure.
634 ****************************************************************************/
635
636 static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
637 {
638 ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
639 write_cache *wcp;
640
641 if (allocated_write_caches >= MAX_WRITE_CACHES)
642 return False;
643
644 if(alloc_size == 0 || fsp->wcp)
645 return False;
646
647 if((wcp = (write_cache *)malloc(sizeof(write_cache))) == NULL) {
648 DEBUG(0,("setup_write_cache: malloc fail.\n"));
649 return False;
650 }
651
652 wcp->file_size = file_size;
653 wcp->offset = 0;
654 wcp->alloc_size = alloc_size;
655 wcp->data_size = 0;
656 if((wcp->data = malloc(wcp->alloc_size)) == NULL) {
657 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
658 (unsigned int)wcp->alloc_size ));
659 SAFE_FREE(wcp);
660 return False;
661 }
662
663 memset(wcp->data, '\0', wcp->alloc_size );
664
665 fsp->wcp = wcp;
666 DO_PROFILE_INC(writecache_allocated_write_caches);
667 allocated_write_caches++;
668
669 DEBUG(10,("setup_write_cache: File %s allocated write cache size %u\n",
670 fsp->fsp_name, wcp->alloc_size ));
671
672 return True;
673 }
674
675 /****************************************************************************
676 Cope with a size change.
677 ****************************************************************************/
678
679 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
680 {
681 fsp->size = file_size;
682 if(fsp->wcp) {
683 /* The cache *must* have been flushed before we do this. */
684 if (fsp->wcp->data_size != 0) {
685 pstring msg;
686 slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
687 on file %s with write cache size = %u\n", fsp->fsp_name, fsp->wcp->data_size );
688 smb_panic(msg);
689 }
690 fsp->wcp->file_size = file_size;
691 }
692 }
693
694 /*******************************************************************
695 Flush a write cache struct to disk.
696 ********************************************************************/
697
698 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
699 {
700 write_cache *wcp = fsp->wcp;
701 size_t data_size;
702 ssize_t ret;
703
704 if(!wcp || !wcp->data_size)
705 return 0;
706
707 data_size = wcp->data_size;
708 wcp->data_size = 0;
709
710 DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
711
712 DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
713 fsp->fd, (double)wcp->offset, (unsigned int)data_size));
714
715 #ifdef WITH_PROFILE
716 if(data_size == wcp->alloc_size)
717 DO_PROFILE_INC(writecache_num_perfect_writes);
718 #endif
719
720 ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
721
722 /*
723 * Ensure file size if kept up to date if write extends file.
724 */
725
726 if ((ret != -1) && (wcp->offset + ret > wcp->file_size))
727 wcp->file_size = wcp->offset + ret;
728
729 return ret;
730 }
731
732 /*******************************************************************
733 sync a file
734 ********************************************************************/
735
736 void sync_file(connection_struct *conn, files_struct *fsp)
737 {
738 if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
739 flush_write_cache(fsp, SYNC_FLUSH);
740 conn->vfs_ops.fsync(fsp,fsp->fd);
741 }
742 }
743
744
745 /************************************************************
746 Perform a stat whether a valid fd or not.
747 ************************************************************/
748
749 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
750 {
751 if (fsp->fd == -1)
752 return vfs_stat(fsp->conn, fsp->fsp_name, pst);
753 else
754 return vfs_fstat(fsp,fsp->fd, pst);
755 }
reg import