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source: branches/samba-3.0/source/smbd/fileio.c@ 770

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Last change on this file since 770 was 62, checked in by Paul Smedley, 18 years ago
Update source to 3.0.25c level
File size: 23.6 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 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	(wcp->file_size == wcp->offset + wcp->data_size) &&
515	(pos < wcp->file_size + wcp->alloc_size)) {
516
517	/*
518
519	End of file ---->\|
520
521	+---------------+---------------+
522	\| Cached data \| Cache buffer \|
523	+---------------+---------------+
524
525	\|<------- allocated size ---------------->\|
526
527	+--------+
528	\| 1 Byte \|
529	+--------+
530
531	MS-Office seems to do this a lot to determine if there's enough
532	space on the filesystem to write a new file.
533
534	Change to :
535
536	End of file ---->\|
537	+-----------------------+--------+
538	\| Zeroed Cached data \| 1 Byte \|
539	+-----------------------+--------+
540	*/
541
542	flush_write_cache(fsp, WRITE_FLUSH);
543	wcp->offset = wcp->file_size;
544	wcp->data_size = pos - wcp->file_size + 1;
545	memset(wcp->data, '\0', wcp->data_size);
546	memcpy(wcp->data + wcp->data_size-1, data, 1);
547
548	/*
549	* Update the file size if changed.
550	*/
551
552	if (wcp->offset + wcp->data_size > wcp->file_size) {
553	if (wcp_file_size_change(fsp) == -1) {
554	return -1;
555	}
556	}
557
558	return n;
559
560	} else {
561
562	/* ASCII art..... JRA.
563
564	Case 1).
565
566	+---------------+---------------+
567	\| Cached data \| Cache buffer \|
568	+---------------+---------------+
569
570	+-------------------+
571	\| Data to write \|
572	+-------------------+
573
574	Case 2).
575
576	+---------------+---------------+
577	\| Cached data \| Cache buffer \|
578	+---------------+---------------+
579
580	+-------------------+
581	\| Data to write \|
582	+-------------------+
583
584	Case 3).
585
586	+---------------+---------------+
587	\| Cached data \| Cache buffer \|
588	+---------------+---------------+
589
590	+-----------------------------------------------------+
591	\| Data to write \|
592	+-----------------------------------------------------+
593
594	*/
595
596	/*
597	* Write is bigger than buffer, or there is no overlap on the
598	* low or high ends.
599	*/
600
601	DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
602	len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
603
604	/*
605	* If write would fit in the cache, and is larger than
606	* the data already in the cache, flush the cache and
607	* preferentially copy the data new data into it. Otherwise
608	* just write the data directly.
609	*/
610
611	if ( n <= wcp->alloc_size && n > wcp->data_size) {
612	cache_flush_needed = True;
613	} else {
614	ssize_t ret = real_write_file(fsp, data, pos, n);
615
616	/*
617	* If the write overlaps the entire cache, then
618	* discard the current contents of the cache.
619	* Fix from Rasmus Borup Hansen rbh@math.ku.dk.
620	*/
621
622	if ((pos <= wcp->offset) &&
623	(pos + n >= wcp->offset + wcp->data_size) ) {
624	DEBUG(9,("write_file: discarding overwritten write \
625	cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
626	wcp->data_size = 0;
627	}
628
629	DO_PROFILE_INC(writecache_direct_writes);
630	if (ret == -1) {
631	return ret;
632	}
633
634	if (pos + ret > wcp->file_size) {
635	wcp->file_size = pos + ret;
636	}
637
638	return ret;
639	}
640
641	write_path = 4;
642
643	}
644
645	if (cache_flush_needed) {
646	DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
647	n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
648	write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
649	(double)wcp->offset, (unsigned int)wcp->data_size ));
650
651	flush_write_cache(fsp, WRITE_FLUSH);
652	}
653	}
654
655	/*
656	* If the write request is bigger than the cache
657	* size, write it all out.
658	*/
659
660	if (n > wcp->alloc_size ) {
661	ssize_t ret = real_write_file(fsp, data, pos, n);
662	if (ret == -1) {
663	return -1;
664	}
665
666	if (pos + ret > wcp->file_size) {
667	wcp->file_size = pos + n;
668	}
669
670	DO_PROFILE_INC(writecache_direct_writes);
671	return total_written + n;
672	}
673
674	/*
675	* If there's any data left, cache it.
676	*/
677
678	if (n) {
679	#ifdef WITH_PROFILE
680	if (wcp->data_size) {
681	DO_PROFILE_INC(writecache_abutted_writes);
682	} else {
683	DO_PROFILE_INC(writecache_init_writes);
684	}
685	#endif
686	memcpy(wcp->data+wcp->data_size, data, n);
687	if (wcp->data_size == 0) {
688	wcp->offset = pos;
689	DO_PROFILE_INC(writecache_num_write_caches);
690	}
691	wcp->data_size += n;
692
693	/*
694	* Update the file size if changed.
695	*/
696
697	if (wcp->offset + wcp->data_size > wcp->file_size) {
698	if (wcp_file_size_change(fsp) == -1) {
699	return -1;
700	}
701	}
702	DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
703	(double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
704
705	total_written += n;
706	return total_written; /* .... that's a write :) */
707	}
708
709	return total_written;
710	}
711
712	/****************************************************************************
713	Delete the write cache structure.
714	****************************************************************************/
715
716	void delete_write_cache(files_struct *fsp)
717	{
718	write_cache *wcp;
719
720	if(!fsp) {
721	return;
722	}
723
724	if(!(wcp = fsp->wcp)) {
725	return;
726	}
727
728	DO_PROFILE_DEC(writecache_allocated_write_caches);
729	allocated_write_caches--;
730
731	SMB_ASSERT(wcp->data_size == 0);
732
733	SAFE_FREE(wcp->data);
734	SAFE_FREE(fsp->wcp);
735
736	DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
737	}
738
739	/****************************************************************************
740	Setup the write cache structure.
741	****************************************************************************/
742
743	static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
744	{
745	ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
746	write_cache *wcp;
747
748	if (allocated_write_caches >= MAX_WRITE_CACHES) {
749	return False;
750	}
751
752	if(alloc_size == 0 \|\| fsp->wcp) {
753	return False;
754	}
755
756	if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
757	DEBUG(0,("setup_write_cache: malloc fail.\n"));
758	return False;
759	}
760
761	wcp->file_size = file_size;
762	wcp->offset = 0;
763	wcp->alloc_size = alloc_size;
764	wcp->data_size = 0;
765	if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
766	DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
767	(unsigned int)wcp->alloc_size ));
768	SAFE_FREE(wcp);
769	return False;
770	}
771
772	memset(wcp->data, '\0', wcp->alloc_size );
773
774	fsp->wcp = wcp;
775	DO_PROFILE_INC(writecache_allocated_write_caches);
776	allocated_write_caches++;
777
778	DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
779	fsp->fsp_name, (unsigned long)wcp->alloc_size ));
780
781	return True;
782	}
783
784	/****************************************************************************
785	Cope with a size change.
786	****************************************************************************/
787
788	void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
789	{
790	if(fsp->wcp) {
791	/* The cache must have been flushed before we do this. */
792	if (fsp->wcp->data_size != 0) {
793	pstring msg;
794	slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
795	on file %s with write cache size = %lu\n", fsp->fsp_name, (unsigned long)fsp->wcp->data_size );
796	smb_panic(msg);
797	}
798	fsp->wcp->file_size = file_size;
799	}
800	}
801
802	/*******************************************************************
803	Flush a write cache struct to disk.
804	********************************************************************/
805
806	ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
807	{
808	write_cache *wcp = fsp->wcp;
809	size_t data_size;
810	ssize_t ret;
811
812	if(!wcp \|\| !wcp->data_size) {
813	return 0;
814	}
815
816	data_size = wcp->data_size;
817	wcp->data_size = 0;
818
819	DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
820
821	DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
822	fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
823
824	#ifdef WITH_PROFILE
825	if(data_size == wcp->alloc_size) {
826	DO_PROFILE_INC(writecache_num_perfect_writes);
827	}
828	#endif
829
830	ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
831
832	/*
833	* Ensure file size if kept up to date if write extends file.
834	*/
835
836	if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
837	wcp->file_size = wcp->offset + ret;
838	}
839
840	return ret;
841	}
842
843	/*******************************************************************
844	sync a file
845	********************************************************************/
846
847	NTSTATUS sync_file(connection_struct conn, files_struct fsp, BOOL write_through)
848	{
849	if (fsp->fh->fd == -1)
850	return NT_STATUS_INVALID_HANDLE;
851
852	if (lp_strict_sync(SNUM(conn)) &&
853	(lp_syncalways(SNUM(conn)) \|\| write_through)) {
854	int ret = flush_write_cache(fsp, SYNC_FLUSH);
855	if (ret == -1) {
856	return map_nt_error_from_unix(errno);
857	}
858	ret = SMB_VFS_FSYNC(fsp,fsp->fh->fd);
859	if (ret == -1) {
860	return map_nt_error_from_unix(errno);
861	}
862	}
863	return NT_STATUS_OK;
864	}
865
866	/************************************************************
867	Perform a stat whether a valid fd or not.
868	************************************************************/
869
870	int fsp_stat(files_struct fsp, SMB_STRUCT_STAT pst)
871	{
872	if (fsp->fh->fd == -1) {
873	return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
874	} else {
875	return SMB_VFS_FSTAT(fsp,fsp->fh->fd, pst);
876	}
877	}

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