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source: branches/samba-3.2.x/source/smbd/fileio.c@ 441

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Last change on this file since 441 was 204, checked in by Herwig Bauernfeind, 16 years ago
Update 3.2 branch to 3.2.4
File size: 25.0 KB

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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	/* 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
160	static 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
174	static void update_write_time_handler(struct event_context *ctx,
175	struct timed_event *te,
176	const struct timeval *now,
177	void *private_data)
178	{
179	files_struct fsp = (files_struct )private_data;
180
181	/* Remove the timed event handler. */
182	TALLOC_FREE(fsp->update_write_time_event);
183	DEBUG(5, ("Update write time on %s\n", fsp->fsp_name));
184
185	/* change the write time if not already changed by someone else */
186	update_write_time(fsp);
187	}
188
189	/*********************************************************
190	Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
191	in the future.
192	*********************************************************/
193
194	void trigger_write_time_update(struct files_struct *fsp)
195	{
196	int delay;
197
198	if (fsp->write_time_forced) {
199	/* No point - "sticky" write times
200	* in effect.
201	*/
202	return;
203	}
204
205	if (fsp->update_write_time_triggered) {
206	/*
207	* We only update the write time
208	* on the first write. After that
209	* no other writes affect this.
210	*/
211	return;
212	}
213	fsp->update_write_time_triggered = true;
214
215	delay = lp_parm_int(SNUM(fsp->conn),
216	"smbd", "writetimeupdatedelay",
217	WRITE_TIME_UPDATE_USEC_DELAY);
218
219	/* trigger the update 2 seconds later */
220	fsp->update_write_time_on_close = true;
221	fsp->update_write_time_event =
222	event_add_timed(smbd_event_context(), NULL,
223	timeval_current_ofs(0, delay),
224	"update_write_time_handler",
225	update_write_time_handler, fsp);
226	}
227
228	void trigger_write_time_update_immediate(struct files_struct *fsp)
229	{
230	if (fsp->write_time_forced) {
231	/*
232	* No point - "sticky" write times
233	* in effect.
234	*/
235	return;
236	}
237
238	TALLOC_FREE(fsp->update_write_time_event);
239	DEBUG(5, ("Update write time immediate on %s\n", fsp->fsp_name));
240
241	fsp->update_write_time_triggered = true;
242
243	fsp->update_write_time_on_close = false;
244	update_write_time(fsp);
245	}
246
247	/****************************************************************************
248	Write to a file.
249	****************************************************************************/
250
251	ssize_t write_file(struct smb_request *req,
252	files_struct *fsp,
253	const char *data,
254	SMB_OFF_T pos,
255	size_t n)
256	{
257	write_cache *wcp = fsp->wcp;
258	ssize_t total_written = 0;
259	int write_path = -1;
260
261	if (fsp->print_file) {
262	fstring sharename;
263	uint32 jobid;
264
265	if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &jobid)) {
266	DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
267	(unsigned int)fsp->rap_print_jobid ));
268	errno = EBADF;
269	return -1;
270	}
271
272	return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
273	}
274
275	if (!fsp->can_write) {
276	errno = EPERM;
277	return -1;
278	}
279
280	if (!fsp->modified) {
281	SMB_STRUCT_STAT st;
282	fsp->modified = True;
283
284	if (SMB_VFS_FSTAT(fsp, &st) == 0) {
285	int dosmode;
286	trigger_write_time_update(fsp);
287	dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
288	if ((lp_store_dos_attributes(SNUM(fsp->conn)) \|\|
289	MAP_ARCHIVE(fsp->conn)) &&
290	!IS_DOS_ARCHIVE(dosmode)) {
291	file_set_dosmode(fsp->conn,fsp->fsp_name,
292	dosmode \| aARCH,&st,
293	NULL,
294	false);
295	}
296
297	/*
298	* If this is the first write and we have an exclusive oplock then setup
299	* the write cache.
300	*/
301
302	if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
303	setup_write_cache(fsp, st.st_size);
304	wcp = fsp->wcp;
305	}
306	}
307	}
308
309	#ifdef WITH_PROFILE
310	DO_PROFILE_INC(writecache_total_writes);
311	if (!fsp->oplock_type) {
312	DO_PROFILE_INC(writecache_non_oplock_writes);
313	}
314	#endif
315
316	/*
317	* If this file is level II oplocked then we need
318	* to grab the shared memory lock and inform all
319	* other files with a level II lock that they need
320	* to flush their read caches. We keep the lock over
321	* the shared memory area whilst doing this.
322	*/
323
324	release_level_2_oplocks_on_change(fsp);
325
326	#ifdef WITH_PROFILE
327	if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
328	DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
329	nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
330	profile_p->writecache_init_writes,
331	profile_p->writecache_abutted_writes,
332	profile_p->writecache_total_writes,
333	profile_p->writecache_non_oplock_writes,
334	profile_p->writecache_allocated_write_caches,
335	profile_p->writecache_num_write_caches,
336	profile_p->writecache_direct_writes,
337	profile_p->writecache_num_perfect_writes,
338	profile_p->writecache_read_hits ));
339
340	DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
341	profile_p->writecache_flushed_writes[SEEK_FLUSH],
342	profile_p->writecache_flushed_writes[READ_FLUSH],
343	profile_p->writecache_flushed_writes[WRITE_FLUSH],
344	profile_p->writecache_flushed_writes[READRAW_FLUSH],
345	profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
346	profile_p->writecache_flushed_writes[CLOSE_FLUSH],
347	profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
348	}
349	#endif
350
351	if (wcp && req->unread_bytes) {
352	/* If we're using receivefile don't
353	* deal with a write cache.
354	*/
355	flush_write_cache(fsp, WRITE_FLUSH);
356	delete_write_cache(fsp);
357	wcp = NULL;
358	}
359
360	if(!wcp) {
361	DO_PROFILE_INC(writecache_direct_writes);
362	total_written = real_write_file(req, fsp, data, pos, n);
363	return total_written;
364	}
365
366	DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
367	fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
368
369	fsp->fh->pos = pos + n;
370
371	/*
372	* If we have active cache and it isn't contiguous then we flush.
373	* NOTE: There is a small problem with running out of disk ....
374	*/
375
376	if (wcp->data_size) {
377	bool cache_flush_needed = False;
378
379	if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
380
381	/* ASCII art.... JRA.
382
383	+--------------+-----
384	\| Cached data \| Rest of allocated cache buffer....
385	+--------------+-----
386
387	+-------------------+
388	\| Data to write \|
389	+-------------------+
390
391	*/
392
393	/*
394	* Start of write overlaps or abutts the existing data.
395	*/
396
397	size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
398
399	memcpy(wcp->data + (pos - wcp->offset), data, data_used);
400
401	/*
402	* Update the current buffer size with the new data.
403	*/
404
405	if(pos + data_used > wcp->offset + wcp->data_size) {
406	wcp->data_size = pos + data_used - wcp->offset;
407	}
408
409	/*
410	* Update the file size if changed.
411	*/
412
413	if (wcp->offset + wcp->data_size > wcp->file_size) {
414	if (wcp_file_size_change(fsp) == -1) {
415	return -1;
416	}
417	}
418
419	/*
420	* If we used all the data then
421	* return here.
422	*/
423
424	if(n == data_used) {
425	return n;
426	} else {
427	cache_flush_needed = True;
428	}
429	/*
430	* Move the start of data forward by the amount used,
431	* cut down the amount left by the same amount.
432	*/
433
434	data += data_used;
435	pos += data_used;
436	n -= data_used;
437
438	DO_PROFILE_INC(writecache_abutted_writes);
439	total_written = data_used;
440
441	write_path = 1;
442
443	} else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
444	(pos + n <= wcp->offset + wcp->alloc_size)) {
445
446	/* ASCII art.... JRA.
447
448	+---------------+
449	\| Cache buffer \|
450	+---------------+
451
452	+-------------------+
453	\| Data to write \|
454	+-------------------+
455
456	*/
457
458	/*
459	* End of write overlaps the existing data.
460	*/
461
462	size_t data_used = pos + n - wcp->offset;
463
464	memcpy(wcp->data, data + n - data_used, data_used);
465
466	/*
467	* Update the current buffer size with the new data.
468	*/
469
470	if(pos + n > wcp->offset + wcp->data_size) {
471	wcp->data_size = pos + n - wcp->offset;
472	}
473
474	/*
475	* Update the file size if changed.
476	*/
477
478	if (wcp->offset + wcp->data_size > wcp->file_size) {
479	if (wcp_file_size_change(fsp) == -1) {
480	return -1;
481	}
482	}
483
484	/*
485	* We don't need to move the start of data, but we
486	* cut down the amount left by the amount used.
487	*/
488
489	n -= data_used;
490
491	/*
492	* We cannot have used all the data here.
493	*/
494
495	cache_flush_needed = True;
496
497	DO_PROFILE_INC(writecache_abutted_writes);
498	total_written = data_used;
499
500	write_path = 2;
501
502	} else if ( (pos >= wcp->file_size) &&
503	(wcp->offset + wcp->data_size == wcp->file_size) &&
504	(pos > wcp->offset + wcp->data_size) &&
505	(pos < wcp->offset + wcp->alloc_size) ) {
506
507	/* ASCII art.... JRA.
508
509	End of file ---->\|
510
511	+---------------+---------------+
512	\| Cached data \| Cache buffer \|
513	+---------------+---------------+
514
515	+-------------------+
516	\| Data to write \|
517	+-------------------+
518
519	*/
520
521	/*
522	* Non-contiguous write part of which fits within
523	* the cache buffer and is extending the file
524	* and the cache contents reflect the current
525	* data up to the current end of the file.
526	*/
527
528	size_t data_used;
529
530	if(pos + n <= wcp->offset + wcp->alloc_size) {
531	data_used = n;
532	} else {
533	data_used = wcp->offset + wcp->alloc_size - pos;
534	}
535
536	/*
537	* Fill in the non-continuous area with zeros.
538	*/
539
540	memset(wcp->data + wcp->data_size, '\0',
541	pos - (wcp->offset + wcp->data_size) );
542
543	memcpy(wcp->data + (pos - wcp->offset), data, data_used);
544
545	/*
546	* Update the current buffer size with the new data.
547	*/
548
549	if(pos + data_used > wcp->offset + wcp->data_size) {
550	wcp->data_size = pos + data_used - wcp->offset;
551	}
552
553	/*
554	* Update the file size if changed.
555	*/
556
557	if (wcp->offset + wcp->data_size > wcp->file_size) {
558	if (wcp_file_size_change(fsp) == -1) {
559	return -1;
560	}
561	}
562
563	/*
564	* If we used all the data then
565	* return here.
566	*/
567
568	if(n == data_used) {
569	return n;
570	} else {
571	cache_flush_needed = True;
572	}
573
574	/*
575	* Move the start of data forward by the amount used,
576	* cut down the amount left by the same amount.
577	*/
578
579	data += data_used;
580	pos += data_used;
581	n -= data_used;
582
583	DO_PROFILE_INC(writecache_abutted_writes);
584	total_written = data_used;
585
586	write_path = 3;
587
588	} else if ( (pos >= wcp->file_size) &&
589	(n == 1) &&
590	(wcp->file_size == wcp->offset + wcp->data_size) &&
591	(pos < wcp->file_size + wcp->alloc_size)) {
592
593	/*
594
595	End of file ---->\|
596
597	+---------------+---------------+
598	\| Cached data \| Cache buffer \|
599	+---------------+---------------+
600
601	\|<------- allocated size ---------------->\|
602
603	+--------+
604	\| 1 Byte \|
605	+--------+
606
607	MS-Office seems to do this a lot to determine if there's enough
608	space on the filesystem to write a new file.
609
610	Change to :
611
612	End of file ---->\|
613	+-----------------------+--------+
614	\| Zeroed Cached data \| 1 Byte \|
615	+-----------------------+--------+
616	*/
617
618	flush_write_cache(fsp, WRITE_FLUSH);
619	wcp->offset = wcp->file_size;
620	wcp->data_size = pos - wcp->file_size + 1;
621	memset(wcp->data, '\0', wcp->data_size);
622	memcpy(wcp->data + wcp->data_size-1, data, 1);
623
624	/*
625	* Update the file size if changed.
626	*/
627
628	if (wcp->offset + wcp->data_size > wcp->file_size) {
629	if (wcp_file_size_change(fsp) == -1) {
630	return -1;
631	}
632	}
633
634	return n;
635
636	} else {
637
638	/* ASCII art..... JRA.
639
640	Case 1).
641
642	+---------------+---------------+
643	\| Cached data \| Cache buffer \|
644	+---------------+---------------+
645
646	+-------------------+
647	\| Data to write \|
648	+-------------------+
649
650	Case 2).
651
652	+---------------+---------------+
653	\| Cached data \| Cache buffer \|
654	+---------------+---------------+
655
656	+-------------------+
657	\| Data to write \|
658	+-------------------+
659
660	Case 3).
661
662	+---------------+---------------+
663	\| Cached data \| Cache buffer \|
664	+---------------+---------------+
665
666	+-----------------------------------------------------+
667	\| Data to write \|
668	+-----------------------------------------------------+
669
670	*/
671
672	/*
673	* Write is bigger than buffer, or there is no overlap on the
674	* low or high ends.
675	*/
676
677	DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
678	len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
679
680	/*
681	* If write would fit in the cache, and is larger than
682	* the data already in the cache, flush the cache and
683	* preferentially copy the data new data into it. Otherwise
684	* just write the data directly.
685	*/
686
687	if ( n <= wcp->alloc_size && n > wcp->data_size) {
688	cache_flush_needed = True;
689	} else {
690	ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
691
692	/*
693	* If the write overlaps the entire cache, then
694	* discard the current contents of the cache.
695	* Fix from Rasmus Borup Hansen rbh@math.ku.dk.
696	*/
697
698	if ((pos <= wcp->offset) &&
699	(pos + n >= wcp->offset + wcp->data_size) ) {
700	DEBUG(9,("write_file: discarding overwritten write \
701	cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
702	wcp->data_size = 0;
703	}
704
705	DO_PROFILE_INC(writecache_direct_writes);
706	if (ret == -1) {
707	return ret;
708	}
709
710	if (pos + ret > wcp->file_size) {
711	wcp->file_size = pos + ret;
712	}
713
714	return ret;
715	}
716
717	write_path = 4;
718
719	}
720
721	if (cache_flush_needed) {
722	DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
723	n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
724	write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
725	(double)wcp->offset, (unsigned int)wcp->data_size ));
726
727	flush_write_cache(fsp, WRITE_FLUSH);
728	}
729	}
730
731	/*
732	* If the write request is bigger than the cache
733	* size, write it all out.
734	*/
735
736	if (n > wcp->alloc_size ) {
737	ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
738	if (ret == -1) {
739	return -1;
740	}
741
742	if (pos + ret > wcp->file_size) {
743	wcp->file_size = pos + n;
744	}
745
746	DO_PROFILE_INC(writecache_direct_writes);
747	return total_written + n;
748	}
749
750	/*
751	* If there's any data left, cache it.
752	*/
753
754	if (n) {
755	#ifdef WITH_PROFILE
756	if (wcp->data_size) {
757	DO_PROFILE_INC(writecache_abutted_writes);
758	} else {
759	DO_PROFILE_INC(writecache_init_writes);
760	}
761	#endif
762	memcpy(wcp->data+wcp->data_size, data, n);
763	if (wcp->data_size == 0) {
764	wcp->offset = pos;
765	DO_PROFILE_INC(writecache_num_write_caches);
766	}
767	wcp->data_size += n;
768
769	/*
770	* Update the file size if changed.
771	*/
772
773	if (wcp->offset + wcp->data_size > wcp->file_size) {
774	if (wcp_file_size_change(fsp) == -1) {
775	return -1;
776	}
777	}
778	DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
779	(double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
780
781	total_written += n;
782	return total_written; /* .... that's a write :) */
783	}
784
785	return total_written;
786	}
787
788	/****************************************************************************
789	Delete the write cache structure.
790	****************************************************************************/
791
792	void delete_write_cache(files_struct *fsp)
793	{
794	write_cache *wcp;
795
796	if(!fsp) {
797	return;
798	}
799
800	if(!(wcp = fsp->wcp)) {
801	return;
802	}
803
804	DO_PROFILE_DEC(writecache_allocated_write_caches);
805	allocated_write_caches--;
806
807	SMB_ASSERT(wcp->data_size == 0);
808
809	SAFE_FREE(wcp->data);
810	SAFE_FREE(fsp->wcp);
811
812	DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
813	}
814
815	/****************************************************************************
816	Setup the write cache structure.
817	****************************************************************************/
818
819	static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
820	{
821	ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
822	write_cache *wcp;
823
824	if (allocated_write_caches >= MAX_WRITE_CACHES) {
825	return False;
826	}
827
828	if(alloc_size == 0 \|\| fsp->wcp) {
829	return False;
830	}
831
832	if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
833	DEBUG(0,("setup_write_cache: malloc fail.\n"));
834	return False;
835	}
836
837	wcp->file_size = file_size;
838	wcp->offset = 0;
839	wcp->alloc_size = alloc_size;
840	wcp->data_size = 0;
841	if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
842	DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
843	(unsigned int)wcp->alloc_size ));
844	SAFE_FREE(wcp);
845	return False;
846	}
847
848	memset(wcp->data, '\0', wcp->alloc_size );
849
850	fsp->wcp = wcp;
851	DO_PROFILE_INC(writecache_allocated_write_caches);
852	allocated_write_caches++;
853
854	DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
855	fsp->fsp_name, (unsigned long)wcp->alloc_size ));
856
857	return True;
858	}
859
860	/****************************************************************************
861	Cope with a size change.
862	****************************************************************************/
863
864	void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
865	{
866	if(fsp->wcp) {
867	/* The cache must have been flushed before we do this. */
868	if (fsp->wcp->data_size != 0) {
869	char *msg;
870	asprintf(&msg, "set_filelen_write_cache: size change "
871	"on file %s with write cache size = %lu\n",
872	fsp->fsp_name,
873	(unsigned long)fsp->wcp->data_size);
874	smb_panic(msg);
875	}
876	fsp->wcp->file_size = file_size;
877	}
878	}
879
880	/*******************************************************************
881	Flush a write cache struct to disk.
882	********************************************************************/
883
884	ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
885	{
886	write_cache *wcp = fsp->wcp;
887	size_t data_size;
888	ssize_t ret;
889
890	if(!wcp \|\| !wcp->data_size) {
891	return 0;
892	}
893
894	data_size = wcp->data_size;
895	wcp->data_size = 0;
896
897	DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
898
899	DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
900	fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
901
902	#ifdef WITH_PROFILE
903	if(data_size == wcp->alloc_size) {
904	DO_PROFILE_INC(writecache_num_perfect_writes);
905	}
906	#endif
907
908	ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
909
910	/*
911	* Ensure file size if kept up to date if write extends file.
912	*/
913
914	if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
915	wcp->file_size = wcp->offset + ret;
916	}
917
918	return ret;
919	}
920
921	/*******************************************************************
922	sync a file
923	********************************************************************/
924
925	NTSTATUS sync_file(connection_struct conn, files_struct fsp, bool write_through)
926	{
927	if (fsp->fh->fd == -1)
928	return NT_STATUS_INVALID_HANDLE;
929
930	if (lp_strict_sync(SNUM(conn)) &&
931	(lp_syncalways(SNUM(conn)) \|\| write_through)) {
932	int ret = flush_write_cache(fsp, SYNC_FLUSH);
933	if (ret == -1) {
934	return map_nt_error_from_unix(errno);
935	}
936	ret = SMB_VFS_FSYNC(fsp);
937	if (ret == -1) {
938	return map_nt_error_from_unix(errno);
939	}
940	}
941	return NT_STATUS_OK;
942	}
943
944	/************************************************************
945	Perform a stat whether a valid fd or not.
946	************************************************************/
947
948	int fsp_stat(files_struct fsp, SMB_STRUCT_STAT pst)
949	{
950	if (fsp->fh->fd == -1) {
951	return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
952	} else {
953	return SMB_VFS_FSTAT(fsp, pst);
954	}
955	}

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