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source: branches/samba-3.5.x/source3/smbd/fileio.c@ 791

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Last change on this file since 791 was 590, checked in by Herwig Bauernfeind, 14 years ago
Samba 3.5: Update trunk to 3.5.6
File size: 26.1 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	#include "smbd/globals.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	errno = EBADF;
61	return -1;
62	}
63
64	/*
65	* Serve from write cache if we can.
66	*/
67
68	if(read_from_write_cache(fsp, data, pos, n)) {
69	fsp->fh->pos = pos + n;
70	fsp->fh->position_information = fsp->fh->pos;
71	return n;
72	}
73
74	flush_write_cache(fsp, READ_FLUSH);
75
76	fsp->fh->pos = pos;
77
78	if (n > 0) {
79	#ifdef DMF_FIX
80	int numretries = 3;
81	tryagain:
82	readret = SMB_VFS_PREAD(fsp,data,n,pos);
83
84	if (readret == -1) {
85	if ((errno == EAGAIN) && numretries) {
86	DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
87	(void)sleep(10);
88	--numretries;
89	goto tryagain;
90	}
91	return -1;
92	}
93	#else /* NO DMF fix. */
94	readret = SMB_VFS_PREAD(fsp,data,n,pos);
95
96	if (readret == -1) {
97	return -1;
98	}
99	#endif
100	if (readret > 0) {
101	ret += readret;
102	}
103	}
104
105	DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
106	fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
107
108	fsp->fh->pos += ret;
109	fsp->fh->position_information = fsp->fh->pos;
110
111	return(ret);
112	}
113
114	/****************************************************************************
115	Really write to a file.
116	****************************************************************************/
117
118	static ssize_t real_write_file(struct smb_request *req,
119	files_struct *fsp,
120	const char *data,
121	SMB_OFF_T pos,
122	size_t n)
123	{
124	ssize_t ret;
125
126	if (pos == -1) {
127	ret = vfs_write_data(req, fsp, data, n);
128	} else {
129	fsp->fh->pos = pos;
130	if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
131	if (vfs_fill_sparse(fsp, pos) == -1) {
132	return -1;
133	}
134	}
135	ret = vfs_pwrite_data(req, fsp, data, n, pos);
136	}
137
138	DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
139	fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
140
141	if (ret != -1) {
142	fsp->fh->pos += ret;
143
144	/* Yes - this is correct - writes don't update this. JRA. */
145	/* Found by Samba4 tests. */
146	#if 0
147	fsp->position_information = fsp->pos;
148	#endif
149	}
150
151	return ret;
152	}
153
154	/****************************************************************************
155	File size cache change.
156	Updates size on disk but doesn't flush the cache.
157	****************************************************************************/
158
159	static int wcp_file_size_change(files_struct *fsp)
160	{
161	int ret;
162	write_cache *wcp = fsp->wcp;
163
164	wcp->file_size = wcp->offset + wcp->data_size;
165	ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
166	if (ret == -1) {
167	DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f "
168	"error %s\n", fsp_str_dbg(fsp),
169	(double)wcp->file_size, strerror(errno)));
170	}
171	return ret;
172	}
173
174	void update_write_time_handler(struct event_context *ctx,
175	struct timed_event *te,
176	struct timeval now,
177	void *private_data)
178	{
179	files_struct fsp = (files_struct )private_data;
180
181	DEBUG(5, ("Update write time on %s\n", fsp_str_dbg(fsp)));
182
183	/* change the write time in the open file db. */
184	(void)set_write_time(fsp->file_id, timespec_current());
185
186	/* And notify. */
187	notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED,
188	FILE_NOTIFY_CHANGE_LAST_WRITE, fsp->fsp_name->base_name);
189
190	/* Remove the timed event handler. */
191	TALLOC_FREE(fsp->update_write_time_event);
192	}
193
194	/*********************************************************
195	Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
196	in the future.
197	*********************************************************/
198
199	void trigger_write_time_update(struct files_struct *fsp)
200	{
201	int delay;
202
203	if (fsp->posix_open) {
204	/* Don't use delayed writes on POSIX files. */
205	return;
206	}
207
208	if (fsp->write_time_forced) {
209	/* No point - "sticky" write times
210	* in effect.
211	*/
212	return;
213	}
214
215	/* We need to remember someone did a write
216	* and update to current time on close. */
217
218	fsp->update_write_time_on_close = true;
219
220	if (fsp->update_write_time_triggered) {
221	/*
222	* We only update the write time after 2 seconds
223	* on the first normal write. After that
224	* no other writes affect this until close.
225	*/
226	return;
227	}
228	fsp->update_write_time_triggered = true;
229
230	delay = lp_parm_int(SNUM(fsp->conn),
231	"smbd", "writetimeupdatedelay",
232	WRITE_TIME_UPDATE_USEC_DELAY);
233
234	DEBUG(5, ("Update write time %d usec later on %s\n",
235	delay, fsp_str_dbg(fsp)));
236
237	/* trigger the update 2 seconds later */
238	fsp->update_write_time_event =
239	event_add_timed(smbd_event_context(), NULL,
240	timeval_current_ofs(0, delay),
241	update_write_time_handler, fsp);
242	}
243
244	void trigger_write_time_update_immediate(struct files_struct *fsp)
245	{
246	struct smb_file_time ft;
247
248	if (fsp->posix_open) {
249	/* Don't use delayed writes on POSIX files. */
250	return;
251	}
252
253	if (fsp->write_time_forced) {
254	/*
255	* No point - "sticky" write times
256	* in effect.
257	*/
258	return;
259	}
260
261	TALLOC_FREE(fsp->update_write_time_event);
262	DEBUG(5, ("Update write time immediate on %s\n",
263	fsp_str_dbg(fsp)));
264
265	/* After an immediate update, reset the trigger. */
266	fsp->update_write_time_triggered = true;
267	fsp->update_write_time_on_close = false;
268
269	ZERO_STRUCT(ft);
270	ft.mtime = timespec_current();
271
272	/* Update the time in the open file db. */
273	(void)set_write_time(fsp->file_id, ft.mtime);
274
275	/* Now set on disk - takes care of notify. */
276	(void)smb_set_file_time(fsp->conn, fsp, fsp->fsp_name, &ft, false);
277	}
278
279	/****************************************************************************
280	Write to a file.
281	****************************************************************************/
282
283	ssize_t write_file(struct smb_request *req,
284	files_struct *fsp,
285	const char *data,
286	SMB_OFF_T pos,
287	size_t n)
288	{
289	write_cache *wcp = fsp->wcp;
290	ssize_t total_written = 0;
291	int write_path = -1;
292
293	if (fsp->print_file) {
294	uint32 jobid;
295
296	if (!rap_to_pjobid(fsp->rap_print_jobid, NULL, &jobid)) {
297	DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
298	(unsigned int)fsp->rap_print_jobid ));
299	errno = EBADF;
300	return -1;
301	}
302
303	return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
304	}
305
306	if (!fsp->can_write) {
307	errno = EPERM;
308	return -1;
309	}
310
311	if (!fsp->modified) {
312	fsp->modified = True;
313
314	if (SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st) == 0) {
315	trigger_write_time_update(fsp);
316	if (!fsp->posix_open &&
317	(lp_store_dos_attributes(SNUM(fsp->conn)) \|\|
318	MAP_ARCHIVE(fsp->conn))) {
319	int dosmode = dos_mode(fsp->conn, fsp->fsp_name);
320	if (!IS_DOS_ARCHIVE(dosmode)) {
321	file_set_dosmode(fsp->conn, fsp->fsp_name,
322	dosmode \| aARCH, NULL, false);
323	}
324	}
325
326	/*
327	* If this is the first write and we have an exclusive oplock then setup
328	* the write cache.
329	*/
330
331	if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
332	setup_write_cache(fsp,
333	fsp->fsp_name->st.st_ex_size);
334	wcp = fsp->wcp;
335	}
336	}
337	}
338
339	#ifdef WITH_PROFILE
340	DO_PROFILE_INC(writecache_total_writes);
341	if (!fsp->oplock_type) {
342	DO_PROFILE_INC(writecache_non_oplock_writes);
343	}
344	#endif
345
346	/*
347	* If this file is level II oplocked then we need
348	* to grab the shared memory lock and inform all
349	* other files with a level II lock that they need
350	* to flush their read caches. We keep the lock over
351	* the shared memory area whilst doing this.
352	*/
353
354	/* This should actually be improved to span the write. */
355	contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
356	contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
357
358	#ifdef WITH_PROFILE
359	if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
360	DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
361	nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
362	profile_p->writecache_init_writes,
363	profile_p->writecache_abutted_writes,
364	profile_p->writecache_total_writes,
365	profile_p->writecache_non_oplock_writes,
366	profile_p->writecache_allocated_write_caches,
367	profile_p->writecache_num_write_caches,
368	profile_p->writecache_direct_writes,
369	profile_p->writecache_num_perfect_writes,
370	profile_p->writecache_read_hits ));
371
372	DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
373	profile_p->writecache_flushed_writes[SEEK_FLUSH],
374	profile_p->writecache_flushed_writes[READ_FLUSH],
375	profile_p->writecache_flushed_writes[WRITE_FLUSH],
376	profile_p->writecache_flushed_writes[READRAW_FLUSH],
377	profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
378	profile_p->writecache_flushed_writes[CLOSE_FLUSH],
379	profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
380	}
381	#endif
382
383	if (wcp && req->unread_bytes) {
384	/* If we're using receivefile don't
385	* deal with a write cache.
386	*/
387	flush_write_cache(fsp, WRITE_FLUSH);
388	delete_write_cache(fsp);
389	wcp = NULL;
390	}
391
392	if(!wcp) {
393	DO_PROFILE_INC(writecache_direct_writes);
394	total_written = real_write_file(req, fsp, data, pos, n);
395	return total_written;
396	}
397
398	DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f "
399	"wcp->data_size=%u\n", fsp_str_dbg(fsp), fsp->fh->fd,
400	(double)pos, (unsigned int)n, (double)wcp->offset,
401	(unsigned int)wcp->data_size));
402
403	fsp->fh->pos = pos + n;
404
405	/*
406	* If we have active cache and it isn't contiguous then we flush.
407	* NOTE: There is a small problem with running out of disk ....
408	*/
409
410	if (wcp->data_size) {
411	bool cache_flush_needed = False;
412
413	if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
414
415	/* ASCII art.... JRA.
416
417	+--------------+-----
418	\| Cached data \| Rest of allocated cache buffer....
419	+--------------+-----
420
421	+-------------------+
422	\| Data to write \|
423	+-------------------+
424
425	*/
426
427	/*
428	* Start of write overlaps or abutts the existing data.
429	*/
430
431	size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
432
433	memcpy(wcp->data + (pos - wcp->offset), data, data_used);
434
435	/*
436	* Update the current buffer size with the new data.
437	*/
438
439	if(pos + data_used > wcp->offset + wcp->data_size) {
440	wcp->data_size = pos + data_used - wcp->offset;
441	}
442
443	/*
444	* Update the file size if changed.
445	*/
446
447	if (wcp->offset + wcp->data_size > wcp->file_size) {
448	if (wcp_file_size_change(fsp) == -1) {
449	return -1;
450	}
451	}
452
453	/*
454	* If we used all the data then
455	* return here.
456	*/
457
458	if(n == data_used) {
459	return n;
460	} else {
461	cache_flush_needed = True;
462	}
463	/*
464	* Move the start of data forward by the amount used,
465	* cut down the amount left by the same amount.
466	*/
467
468	data += data_used;
469	pos += data_used;
470	n -= data_used;
471
472	DO_PROFILE_INC(writecache_abutted_writes);
473	total_written = data_used;
474
475	write_path = 1;
476
477	} else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
478	(pos + n <= wcp->offset + wcp->alloc_size)) {
479
480	/* ASCII art.... JRA.
481
482	+---------------+
483	\| Cache buffer \|
484	+---------------+
485
486	+-------------------+
487	\| Data to write \|
488	+-------------------+
489
490	*/
491
492	/*
493	* End of write overlaps the existing data.
494	*/
495
496	size_t data_used = pos + n - wcp->offset;
497
498	memcpy(wcp->data, data + n - data_used, data_used);
499
500	/*
501	* Update the current buffer size with the new data.
502	*/
503
504	if(pos + n > wcp->offset + wcp->data_size) {
505	wcp->data_size = pos + n - wcp->offset;
506	}
507
508	/*
509	* Update the file size if changed.
510	*/
511
512	if (wcp->offset + wcp->data_size > wcp->file_size) {
513	if (wcp_file_size_change(fsp) == -1) {
514	return -1;
515	}
516	}
517
518	/*
519	* We don't need to move the start of data, but we
520	* cut down the amount left by the amount used.
521	*/
522
523	n -= data_used;
524
525	/*
526	* We cannot have used all the data here.
527	*/
528
529	cache_flush_needed = True;
530
531	DO_PROFILE_INC(writecache_abutted_writes);
532	total_written = data_used;
533
534	write_path = 2;
535
536	} else if ( (pos >= wcp->file_size) &&
537	(wcp->offset + wcp->data_size == wcp->file_size) &&
538	(pos > wcp->offset + wcp->data_size) &&
539	(pos < wcp->offset + wcp->alloc_size) ) {
540
541	/* ASCII art.... JRA.
542
543	End of file ---->\|
544
545	+---------------+---------------+
546	\| Cached data \| Cache buffer \|
547	+---------------+---------------+
548
549	+-------------------+
550	\| Data to write \|
551	+-------------------+
552
553	*/
554
555	/*
556	* Non-contiguous write part of which fits within
557	* the cache buffer and is extending the file
558	* and the cache contents reflect the current
559	* data up to the current end of the file.
560	*/
561
562	size_t data_used;
563
564	if(pos + n <= wcp->offset + wcp->alloc_size) {
565	data_used = n;
566	} else {
567	data_used = wcp->offset + wcp->alloc_size - pos;
568	}
569
570	/*
571	* Fill in the non-continuous area with zeros.
572	*/
573
574	memset(wcp->data + wcp->data_size, '\0',
575	pos - (wcp->offset + wcp->data_size) );
576
577	memcpy(wcp->data + (pos - wcp->offset), data, data_used);
578
579	/*
580	* Update the current buffer size with the new data.
581	*/
582
583	if(pos + data_used > wcp->offset + wcp->data_size) {
584	wcp->data_size = pos + data_used - wcp->offset;
585	}
586
587	/*
588	* Update the file size if changed.
589	*/
590
591	if (wcp->offset + wcp->data_size > wcp->file_size) {
592	if (wcp_file_size_change(fsp) == -1) {
593	return -1;
594	}
595	}
596
597	/*
598	* If we used all the data then
599	* return here.
600	*/
601
602	if(n == data_used) {
603	return n;
604	} else {
605	cache_flush_needed = True;
606	}
607
608	/*
609	* Move the start of data forward by the amount used,
610	* cut down the amount left by the same amount.
611	*/
612
613	data += data_used;
614	pos += data_used;
615	n -= data_used;
616
617	DO_PROFILE_INC(writecache_abutted_writes);
618	total_written = data_used;
619
620	write_path = 3;
621
622	} else if ( (pos >= wcp->file_size) &&
623	(n == 1) &&
624	(wcp->file_size == wcp->offset + wcp->data_size) &&
625	(pos < wcp->file_size + wcp->alloc_size)) {
626
627	/*
628
629	End of file ---->\|
630
631	+---------------+---------------+
632	\| Cached data \| Cache buffer \|
633	+---------------+---------------+
634
635	\|<------- allocated size ---------------->\|
636
637	+--------+
638	\| 1 Byte \|
639	+--------+
640
641	MS-Office seems to do this a lot to determine if there's enough
642	space on the filesystem to write a new file.
643
644	Change to :
645
646	End of file ---->\|
647	+-----------------------+--------+
648	\| Zeroed Cached data \| 1 Byte \|
649	+-----------------------+--------+
650	*/
651
652	flush_write_cache(fsp, WRITE_FLUSH);
653	wcp->offset = wcp->file_size;
654	wcp->data_size = pos - wcp->file_size + 1;
655	memset(wcp->data, '\0', wcp->data_size);
656	memcpy(wcp->data + wcp->data_size-1, data, 1);
657
658	/*
659	* Update the file size if changed.
660	*/
661
662	if (wcp->offset + wcp->data_size > wcp->file_size) {
663	if (wcp_file_size_change(fsp) == -1) {
664	return -1;
665	}
666	}
667
668	return n;
669
670	} else {
671
672	/* ASCII art..... JRA.
673
674	Case 1).
675
676	+---------------+---------------+
677	\| Cached data \| Cache buffer \|
678	+---------------+---------------+
679
680	+-------------------+
681	\| Data to write \|
682	+-------------------+
683
684	Case 2).
685
686	+---------------+---------------+
687	\| Cached data \| Cache buffer \|
688	+---------------+---------------+
689
690	+-------------------+
691	\| Data to write \|
692	+-------------------+
693
694	Case 3).
695
696	+---------------+---------------+
697	\| Cached data \| Cache buffer \|
698	+---------------+---------------+
699
700	+-----------------------------------------------------+
701	\| Data to write \|
702	+-----------------------------------------------------+
703
704	*/
705
706	/*
707	* Write is bigger than buffer, or there is no overlap on the
708	* low or high ends.
709	*/
710
711	DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
712	len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
713
714	/*
715	* If write would fit in the cache, and is larger than
716	* the data already in the cache, flush the cache and
717	* preferentially copy the data new data into it. Otherwise
718	* just write the data directly.
719	*/
720
721	if ( n <= wcp->alloc_size && n > wcp->data_size) {
722	cache_flush_needed = True;
723	} else {
724	ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
725
726	/*
727	* If the write overlaps the entire cache, then
728	* discard the current contents of the cache.
729	* Fix from Rasmus Borup Hansen rbh@math.ku.dk.
730	*/
731
732	if ((pos <= wcp->offset) &&
733	(pos + n >= wcp->offset + wcp->data_size) ) {
734	DEBUG(9,("write_file: discarding overwritten write \
735	cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
736	wcp->data_size = 0;
737	}
738
739	DO_PROFILE_INC(writecache_direct_writes);
740	if (ret == -1) {
741	return ret;
742	}
743
744	if (pos + ret > wcp->file_size) {
745	wcp->file_size = pos + ret;
746	}
747
748	return ret;
749	}
750
751	write_path = 4;
752
753	}
754
755	if (cache_flush_needed) {
756	DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
757	n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
758	write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
759	(double)wcp->offset, (unsigned int)wcp->data_size ));
760
761	flush_write_cache(fsp, WRITE_FLUSH);
762	}
763	}
764
765	/*
766	* If the write request is bigger than the cache
767	* size, write it all out.
768	*/
769
770	if (n > wcp->alloc_size ) {
771	ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
772	if (ret == -1) {
773	return -1;
774	}
775
776	if (pos + ret > wcp->file_size) {
777	wcp->file_size = pos + n;
778	}
779
780	DO_PROFILE_INC(writecache_direct_writes);
781	return total_written + n;
782	}
783
784	/*
785	* If there's any data left, cache it.
786	*/
787
788	if (n) {
789	#ifdef WITH_PROFILE
790	if (wcp->data_size) {
791	DO_PROFILE_INC(writecache_abutted_writes);
792	} else {
793	DO_PROFILE_INC(writecache_init_writes);
794	}
795	#endif
796	memcpy(wcp->data+wcp->data_size, data, n);
797	if (wcp->data_size == 0) {
798	wcp->offset = pos;
799	DO_PROFILE_INC(writecache_num_write_caches);
800	}
801	wcp->data_size += n;
802
803	/*
804	* Update the file size if changed.
805	*/
806
807	if (wcp->offset + wcp->data_size > wcp->file_size) {
808	if (wcp_file_size_change(fsp) == -1) {
809	return -1;
810	}
811	}
812	DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
813	(double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
814
815	total_written += n;
816	return total_written; /* .... that's a write :) */
817	}
818
819	return total_written;
820	}
821
822	/****************************************************************************
823	Delete the write cache structure.
824	****************************************************************************/
825
826	void delete_write_cache(files_struct *fsp)
827	{
828	write_cache *wcp;
829
830	if(!fsp) {
831	return;
832	}
833
834	if(!(wcp = fsp->wcp)) {
835	return;
836	}
837
838	DO_PROFILE_DEC(writecache_allocated_write_caches);
839	allocated_write_caches--;
840
841	SMB_ASSERT(wcp->data_size == 0);
842
843	SAFE_FREE(wcp->data);
844	SAFE_FREE(fsp->wcp);
845
846	DEBUG(10,("delete_write_cache: File %s deleted write cache\n",
847	fsp_str_dbg(fsp)));
848	}
849
850	/****************************************************************************
851	Setup the write cache structure.
852	****************************************************************************/
853
854	static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
855	{
856	ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
857	write_cache *wcp;
858
859	if (allocated_write_caches >= MAX_WRITE_CACHES) {
860	return False;
861	}
862
863	if(alloc_size == 0 \|\| fsp->wcp) {
864	return False;
865	}
866
867	if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
868	DEBUG(0,("setup_write_cache: malloc fail.\n"));
869	return False;
870	}
871
872	wcp->file_size = file_size;
873	wcp->offset = 0;
874	wcp->alloc_size = alloc_size;
875	wcp->data_size = 0;
876	if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
877	DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
878	(unsigned int)wcp->alloc_size ));
879	SAFE_FREE(wcp);
880	return False;
881	}
882
883	memset(wcp->data, '\0', wcp->alloc_size );
884
885	fsp->wcp = wcp;
886	DO_PROFILE_INC(writecache_allocated_write_caches);
887	allocated_write_caches++;
888
889	DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
890	fsp_str_dbg(fsp), (unsigned long)wcp->alloc_size));
891
892	return True;
893	}
894
895	/****************************************************************************
896	Cope with a size change.
897	****************************************************************************/
898
899	void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
900	{
901	if(fsp->wcp) {
902	/* The cache must have been flushed before we do this. */
903	if (fsp->wcp->data_size != 0) {
904	char *msg;
905	if (asprintf(&msg, "set_filelen_write_cache: size change "
906	"on file %s with write cache size = %lu\n",
907	fsp->fsp_name->base_name,
908	(unsigned long)fsp->wcp->data_size) != -1) {
909	smb_panic(msg);
910	} else {
911	smb_panic("set_filelen_write_cache");
912	}
913	}
914	fsp->wcp->file_size = file_size;
915	}
916	}
917
918	/*******************************************************************
919	Flush a write cache struct to disk.
920	********************************************************************/
921
922	ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
923	{
924	write_cache *wcp = fsp->wcp;
925	size_t data_size;
926	ssize_t ret;
927
928	if(!wcp \|\| !wcp->data_size) {
929	return 0;
930	}
931
932	data_size = wcp->data_size;
933	wcp->data_size = 0;
934
935	DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
936
937	DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
938	fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
939
940	#ifdef WITH_PROFILE
941	if(data_size == wcp->alloc_size) {
942	DO_PROFILE_INC(writecache_num_perfect_writes);
943	}
944	#endif
945
946	ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
947
948	/*
949	* Ensure file size if kept up to date if write extends file.
950	*/
951
952	if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
953	wcp->file_size = wcp->offset + ret;
954	}
955
956	return ret;
957	}
958
959	/*******************************************************************
960	sync a file
961	********************************************************************/
962
963	NTSTATUS sync_file(connection_struct conn, files_struct fsp, bool write_through)
964	{
965	if (fsp->fh->fd == -1)
966	return NT_STATUS_INVALID_HANDLE;
967
968	if (lp_strict_sync(SNUM(conn)) &&
969	(lp_syncalways(SNUM(conn)) \|\| write_through)) {
970	int ret = flush_write_cache(fsp, SYNC_FLUSH);
971	if (ret == -1) {
972	return map_nt_error_from_unix(errno);
973	}
974	ret = SMB_VFS_FSYNC(fsp);
975	if (ret == -1) {
976	return map_nt_error_from_unix(errno);
977	}
978	}
979	return NT_STATUS_OK;
980	}
981
982	/************************************************************
983	Perform a stat whether a valid fd or not.
984	************************************************************/
985
986	int fsp_stat(files_struct *fsp)
987	{
988	if (fsp->fh->fd == -1) {
989	if (fsp->posix_open) {
990	return SMB_VFS_LSTAT(fsp->conn, fsp->fsp_name);
991	} else {
992	return SMB_VFS_STAT(fsp->conn, fsp->fsp_name);
993	}
994	} else {
995	return SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st);
996	}
997	}

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