smbd: some write time fixes
[tprouty/samba.git] / source / smbd / oplock.c
1 /* 
2    Unix SMB/CIFS implementation.
3    oplock processing
4    Copyright (C) Andrew Tridgell 1992-1998
5    Copyright (C) Jeremy Allison 1998 - 2001
6    Copyright (C) Volker Lendecke 2005
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 #define DBGC_CLASS DBGC_LOCKING
23 #include "includes.h"
24
25 /* Current number of oplocks we have outstanding. */
26 static int32 exclusive_oplocks_open = 0;
27 static int32 level_II_oplocks_open = 0;
28 bool global_client_failed_oplock_break = False;
29
30 extern uint32 global_client_caps;
31
32 static struct kernel_oplocks *koplocks;
33
34 /****************************************************************************
35  Get the number of current exclusive oplocks.
36 ****************************************************************************/
37
38 int32 get_number_of_exclusive_open_oplocks(void)
39 {
40   return exclusive_oplocks_open;
41 }
42
43 /****************************************************************************
44  Return True if an oplock message is pending.
45 ****************************************************************************/
46
47 bool oplock_message_waiting(fd_set *fds)
48 {
49         if (koplocks && koplocks->msg_waiting(fds)) {
50                 return True;
51         }
52
53         return False;
54 }
55
56 /****************************************************************************
57  Find out if there are any kernel oplock messages waiting and process them
58  if so. pfds is the fd_set from the main select loop (which contains any
59  kernel oplock fd if that's what the system uses (IRIX). If may be NULL if
60  we're calling this in a shutting down state.
61 ****************************************************************************/
62
63 void process_kernel_oplocks(struct messaging_context *msg_ctx, fd_set *pfds)
64 {
65         /*
66          * We need to check for kernel oplocks before going into the select
67          * here, as the EINTR generated by the linux kernel oplock may have
68          * already been eaten. JRA.
69          */
70
71         if (!koplocks) {
72                 return;
73         }
74
75         while (koplocks->msg_waiting(pfds)) { 
76                 files_struct *fsp;
77                 char msg[MSG_SMB_KERNEL_BREAK_SIZE];
78
79                 fsp = koplocks->receive_message(pfds);
80
81                 if (fsp == NULL) {
82                         DEBUG(3, ("Kernel oplock message announced, but none "
83                                   "received\n"));
84                         return;
85                 }
86
87                 /* Put the kernel break info into the message. */
88                 push_file_id_16(msg, &fsp->file_id);
89                 SIVAL(msg,16,fsp->fh->gen_id);
90
91                 /* Don't need to be root here as we're only ever
92                    sending to ourselves. */
93
94                 messaging_send_buf(msg_ctx, procid_self(),
95                                    MSG_SMB_KERNEL_BREAK,
96                                    (uint8 *)&msg, MSG_SMB_KERNEL_BREAK_SIZE);
97         }
98 }
99
100 /****************************************************************************
101  Attempt to set an oplock on a file. Always succeeds if kernel oplocks are
102  disabled (just sets flags). Returns True if oplock set.
103 ****************************************************************************/
104
105 bool set_file_oplock(files_struct *fsp, int oplock_type)
106 {
107         if (koplocks && !koplocks->set_oplock(fsp, oplock_type)) {
108                 return False;
109         }
110
111         fsp->oplock_type = oplock_type;
112         fsp->sent_oplock_break = NO_BREAK_SENT;
113         if (oplock_type == LEVEL_II_OPLOCK) {
114                 level_II_oplocks_open++;
115         } else {
116                 exclusive_oplocks_open++;
117         }
118
119         DEBUG(5,("set_file_oplock: granted oplock on file %s, %s/%lu, "
120                     "tv_sec = %x, tv_usec = %x\n",
121                  fsp->fsp_name, file_id_string_tos(&fsp->file_id),
122                  fsp->fh->gen_id, (int)fsp->open_time.tv_sec,
123                  (int)fsp->open_time.tv_usec ));
124
125         return True;
126 }
127
128 /****************************************************************************
129  Attempt to release an oplock on a file. Decrements oplock count.
130 ****************************************************************************/
131
132 void release_file_oplock(files_struct *fsp)
133 {
134         if ((fsp->oplock_type != NO_OPLOCK) &&
135             (fsp->oplock_type != FAKE_LEVEL_II_OPLOCK) &&
136             koplocks) {
137                 koplocks->release_oplock(fsp);
138         }
139
140         if (fsp->oplock_type == LEVEL_II_OPLOCK) {
141                 level_II_oplocks_open--;
142         } else if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type)) {
143                 exclusive_oplocks_open--;
144         }
145
146         SMB_ASSERT(exclusive_oplocks_open>=0);
147         SMB_ASSERT(level_II_oplocks_open>=0);
148         
149         fsp->oplock_type = NO_OPLOCK;
150         fsp->sent_oplock_break = NO_BREAK_SENT;
151         
152         flush_write_cache(fsp, OPLOCK_RELEASE_FLUSH);
153
154         TALLOC_FREE(fsp->oplock_timeout);
155 }
156
157 /****************************************************************************
158  Attempt to downgrade an oplock on a file. Doesn't decrement oplock count.
159 ****************************************************************************/
160
161 static void downgrade_file_oplock(files_struct *fsp)
162 {
163         if (koplocks) {
164                 koplocks->release_oplock(fsp);
165         }
166         fsp->oplock_type = LEVEL_II_OPLOCK;
167         exclusive_oplocks_open--;
168         level_II_oplocks_open++;
169         fsp->sent_oplock_break = NO_BREAK_SENT;
170 }
171
172 /****************************************************************************
173  Remove a file oplock. Copes with level II and exclusive.
174  Locks then unlocks the share mode lock. Client can decide to go directly
175  to none even if a "break-to-level II" was sent.
176 ****************************************************************************/
177
178 bool remove_oplock(files_struct *fsp)
179 {
180         bool ret;
181         struct share_mode_lock *lck;
182
183         /* Remove the oplock flag from the sharemode. */
184         lck = get_share_mode_lock(talloc_tos(), fsp->file_id, NULL, NULL,
185                                   NULL);
186         if (lck == NULL) {
187                 DEBUG(0,("remove_oplock: failed to lock share entry for "
188                          "file %s\n", fsp->fsp_name ));
189                 return False;
190         }
191         ret = remove_share_oplock(lck, fsp);
192         if (!ret) {
193                 DEBUG(0,("remove_oplock: failed to remove share oplock for "
194                          "file %s fnum %d, %s\n",
195                          fsp->fsp_name, fsp->fnum, file_id_string_tos(&fsp->file_id)));
196         }
197         release_file_oplock(fsp);
198         TALLOC_FREE(lck);
199         return ret;
200 }
201
202 /*
203  * Deal with a reply when a break-to-level II was sent.
204  */
205 bool downgrade_oplock(files_struct *fsp)
206 {
207         bool ret;
208         struct share_mode_lock *lck;
209
210         lck = get_share_mode_lock(talloc_tos(), fsp->file_id, NULL, NULL,
211                                   NULL);
212         if (lck == NULL) {
213                 DEBUG(0,("downgrade_oplock: failed to lock share entry for "
214                          "file %s\n", fsp->fsp_name ));
215                 return False;
216         }
217         ret = downgrade_share_oplock(lck, fsp);
218         if (!ret) {
219                 DEBUG(0,("downgrade_oplock: failed to downgrade share oplock "
220                          "for file %s fnum %d, file_id %s\n",
221                          fsp->fsp_name, fsp->fnum, file_id_string_tos(&fsp->file_id)));
222         }
223
224         downgrade_file_oplock(fsp);
225         TALLOC_FREE(lck);
226         return ret;
227 }
228
229 /****************************************************************************
230  Return the fd (if any) used for receiving oplock notifications.
231 ****************************************************************************/
232
233 int oplock_notify_fd(void)
234 {
235         if (koplocks) {
236                 return koplocks->notification_fd;
237         }
238
239         return -1;
240 }
241
242 /****************************************************************************
243  Set up an oplock break message.
244 ****************************************************************************/
245
246 static char *new_break_smb_message(TALLOC_CTX *mem_ctx,
247                                    files_struct *fsp, uint8 cmd)
248 {
249         char *result = TALLOC_ARRAY(mem_ctx, char, smb_size + 8*2 + 0);
250
251         if (result == NULL) {
252                 DEBUG(0, ("talloc failed\n"));
253                 return NULL;
254         }
255
256         memset(result,'\0',smb_size);
257         srv_set_message(result,8,0,true);
258         SCVAL(result,smb_com,SMBlockingX);
259         SSVAL(result,smb_tid,fsp->conn->cnum);
260         SSVAL(result,smb_pid,0xFFFF);
261         SSVAL(result,smb_uid,0);
262         SSVAL(result,smb_mid,0xFFFF);
263         SCVAL(result,smb_vwv0,0xFF);
264         SSVAL(result,smb_vwv2,fsp->fnum);
265         SCVAL(result,smb_vwv3,LOCKING_ANDX_OPLOCK_RELEASE);
266         SCVAL(result,smb_vwv3+1,cmd);
267         return result;
268 }
269
270 /****************************************************************************
271  Function to do the waiting before sending a local break.
272 ****************************************************************************/
273
274 static void wait_before_sending_break(void)
275 {
276         long wait_time = (long)lp_oplock_break_wait_time();
277
278         if (wait_time) {
279                 smb_msleep(wait_time);
280         }
281 }
282
283 /****************************************************************************
284  Ensure that we have a valid oplock.
285 ****************************************************************************/
286
287 static files_struct *initial_break_processing(struct file_id id, unsigned long file_id)
288 {
289         files_struct *fsp = NULL;
290
291         if( DEBUGLVL( 3 ) ) {
292                 dbgtext( "initial_break_processing: called for %s/%u\n",
293                          file_id_string_tos(&id), (int)file_id);
294                 dbgtext( "Current oplocks_open (exclusive = %d, levelII = %d)\n",
295                         exclusive_oplocks_open, level_II_oplocks_open );
296         }
297
298         /*
299          * We need to search the file open table for the
300          * entry containing this dev and inode, and ensure
301          * we have an oplock on it.
302          */
303
304         fsp = file_find_dif(id, file_id);
305
306         if(fsp == NULL) {
307                 /* The file could have been closed in the meantime - return success. */
308                 if( DEBUGLVL( 3 ) ) {
309                         dbgtext( "initial_break_processing: cannot find open file with " );
310                         dbgtext( "file_id %s gen_id = %lu", file_id_string_tos(&id), file_id);
311                         dbgtext( "allowing break to succeed.\n" );
312                 }
313                 return NULL;
314         }
315
316         /* Ensure we have an oplock on the file */
317
318         /*
319          * There is a potential race condition in that an oplock could
320          * have been broken due to another udp request, and yet there are
321          * still oplock break messages being sent in the udp message
322          * queue for this file. So return true if we don't have an oplock,
323          * as we may have just freed it.
324          */
325
326         if(fsp->oplock_type == NO_OPLOCK) {
327                 if( DEBUGLVL( 3 ) ) {
328                         dbgtext( "initial_break_processing: file %s ", fsp->fsp_name );
329                         dbgtext( "(file_id = %s gen_id = %lu) has no oplock.\n",
330                                  file_id_string_tos(&id), fsp->fh->gen_id );
331                         dbgtext( "Allowing break to succeed regardless.\n" );
332                 }
333                 return NULL;
334         }
335
336         return fsp;
337 }
338
339 static void oplock_timeout_handler(struct event_context *ctx,
340                                    struct timed_event *te,
341                                    const struct timeval *now,
342                                    void *private_data)
343 {
344         files_struct *fsp = (files_struct *)private_data;
345
346         /* Remove the timed event handler. */
347         TALLOC_FREE(fsp->oplock_timeout);
348         DEBUG(0, ("Oplock break failed for file %s -- replying anyway\n", fsp->fsp_name));
349         global_client_failed_oplock_break = True;
350         remove_oplock(fsp);
351         reply_to_oplock_break_requests(fsp);
352 }
353
354 /*******************************************************************
355  Add a timeout handler waiting for the client reply.
356 *******************************************************************/
357
358 static void add_oplock_timeout_handler(files_struct *fsp)
359 {
360         if (fsp->oplock_timeout != NULL) {
361                 DEBUG(0, ("Logic problem -- have an oplock event hanging "
362                           "around\n"));
363         }
364
365         fsp->oplock_timeout =
366                 event_add_timed(smbd_event_context(), NULL,
367                                 timeval_current_ofs(OPLOCK_BREAK_TIMEOUT, 0),
368                                 "oplock_timeout_handler",
369                                 oplock_timeout_handler, fsp);
370
371         if (fsp->oplock_timeout == NULL) {
372                 DEBUG(0, ("Could not add oplock timeout handler\n"));
373         }
374 }
375
376 /*******************************************************************
377  This handles the case of a write triggering a break to none
378  message on a level2 oplock.
379  When we get this message we may be in any of three states :
380  NO_OPLOCK, LEVEL_II, FAKE_LEVEL2. We only send a message to
381  the client for LEVEL2.
382 *******************************************************************/
383
384 static void process_oplock_async_level2_break_message(struct messaging_context *msg_ctx,
385                                                       void *private_data,
386                                                       uint32_t msg_type,
387                                                       struct server_id src,
388                                                       DATA_BLOB *data)
389 {
390         struct share_mode_entry msg;
391         files_struct *fsp;
392         char *break_msg;
393         bool sign_state;
394
395         if (data->data == NULL) {
396                 DEBUG(0, ("Got NULL buffer\n"));
397                 return;
398         }
399
400         if (data->length != MSG_SMB_SHARE_MODE_ENTRY_SIZE) {
401                 DEBUG(0, ("Got invalid msg len %d\n", (int)data->length));
402                 return;
403         }
404
405         /* De-linearize incoming message. */
406         message_to_share_mode_entry(&msg, (char *)data->data);
407
408         DEBUG(10, ("Got oplock async level 2 break message from pid %d: %s/%lu\n",
409                    (int)procid_to_pid(&src), file_id_string_tos(&msg.id), msg.share_file_id));
410
411         fsp = initial_break_processing(msg.id, msg.share_file_id);
412
413         if (fsp == NULL) {
414                 /* We hit a race here. Break messages are sent, and before we
415                  * get to process this message, we have closed the file. 
416                  * No need to reply as this is an async message. */
417                 DEBUG(3, ("process_oplock_async_level2_break_message: Did not find fsp, ignoring\n"));
418                 return;
419         }
420
421         if (fsp->oplock_type == NO_OPLOCK) {
422                 /* We already got a "break to none" message and we've handled it.
423                  * just ignore. */
424                 DEBUG(3, ("process_oplock_async_level2_break_message: already broken to none, ignoring.\n"));
425                 return;
426         }
427
428         if (fsp->oplock_type == FAKE_LEVEL_II_OPLOCK) {
429                 /* Don't tell the client, just downgrade. */
430                 DEBUG(3, ("process_oplock_async_level2_break_message: downgrading fake level 2 oplock.\n"));
431                 remove_oplock(fsp);
432                 return;
433         }
434
435         /* Ensure we're really at level2 state. */
436         SMB_ASSERT(fsp->oplock_type == LEVEL_II_OPLOCK);
437
438         /* Now send a break to none message to our client. */
439
440         break_msg = new_break_smb_message(NULL, fsp, OPLOCKLEVEL_NONE);
441         if (break_msg == NULL) {
442                 exit_server("Could not talloc break_msg\n");
443         }
444
445         /* Need to wait before sending a break message if we sent ourselves this message. */
446         if (procid_to_pid(&src) == sys_getpid()) {
447                 wait_before_sending_break();
448         }
449
450         /* Save the server smb signing state. */
451         sign_state = srv_oplock_set_signing(False);
452
453         show_msg(break_msg);
454         if (!srv_send_smb(smbd_server_fd(),
455                         break_msg,
456                         IS_CONN_ENCRYPTED(fsp->conn))) {
457                 exit_server_cleanly("oplock_break: srv_send_smb failed.");
458         }
459
460         /* Restore the sign state to what it was. */
461         srv_oplock_set_signing(sign_state);
462
463         TALLOC_FREE(break_msg);
464
465         /* Async level2 request, don't send a reply, just remove the oplock. */
466         remove_oplock(fsp);
467 }
468
469 /*******************************************************************
470  This handles the generic oplock break message from another smbd.
471 *******************************************************************/
472
473 static void process_oplock_break_message(struct messaging_context *msg_ctx,
474                                          void *private_data,
475                                          uint32_t msg_type,
476                                          struct server_id src,
477                                          DATA_BLOB *data)
478 {
479         struct share_mode_entry msg;
480         files_struct *fsp;
481         char *break_msg;
482         bool break_to_level2 = False;
483         bool sign_state;
484
485         if (data->data == NULL) {
486                 DEBUG(0, ("Got NULL buffer\n"));
487                 return;
488         }
489
490         if (data->length != MSG_SMB_SHARE_MODE_ENTRY_SIZE) {
491                 DEBUG(0, ("Got invalid msg len %d\n", (int)data->length));
492                 return;
493         }
494
495         /* De-linearize incoming message. */
496         message_to_share_mode_entry(&msg, (char *)data->data);
497
498         DEBUG(10, ("Got oplock break message from pid %d: %s/%lu\n",
499                    (int)procid_to_pid(&src), file_id_string_tos(&msg.id), msg.share_file_id));
500
501         fsp = initial_break_processing(msg.id, msg.share_file_id);
502
503         if (fsp == NULL) {
504                 /* a We hit race here. Break messages are sent, and before we
505                  * get to process this message, we have closed the file. Reply
506                  * with 'ok, oplock broken' */
507                 DEBUG(3, ("Did not find fsp\n"));
508
509                 /* We just send the same message back. */
510                 messaging_send_buf(msg_ctx, src, MSG_SMB_BREAK_RESPONSE,
511                                    (uint8 *)data->data,
512                                    MSG_SMB_SHARE_MODE_ENTRY_SIZE);
513                 return;
514         }
515
516         if (fsp->sent_oplock_break != NO_BREAK_SENT) {
517                 /* Remember we have to inform the requesting PID when the
518                  * client replies */
519                 msg.pid = src;
520                 ADD_TO_ARRAY(NULL, struct share_mode_entry, msg,
521                              &fsp->pending_break_messages,
522                              &fsp->num_pending_break_messages);
523                 return;
524         }
525
526         if (EXCLUSIVE_OPLOCK_TYPE(msg.op_type) &&
527             !EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type)) {
528                 DEBUG(3, ("Already downgraded oplock on %s: %s\n",
529                           file_id_string_tos(&fsp->file_id),
530                           fsp->fsp_name));
531                 /* We just send the same message back. */
532                 messaging_send_buf(msg_ctx, src, MSG_SMB_BREAK_RESPONSE,
533                                    (uint8 *)data->data,
534                                    MSG_SMB_SHARE_MODE_ENTRY_SIZE);
535                 return;
536         }
537
538         if ((global_client_caps & CAP_LEVEL_II_OPLOCKS) && 
539             !(msg.op_type & FORCE_OPLOCK_BREAK_TO_NONE) &&
540             !koplocks && /* NOTE: we force levelII off for kernel oplocks -
541                           * this will change when it is supported */
542             lp_level2_oplocks(SNUM(fsp->conn))) {
543                 break_to_level2 = True;
544         }
545
546         break_msg = new_break_smb_message(NULL, fsp, break_to_level2 ?
547                                           OPLOCKLEVEL_II : OPLOCKLEVEL_NONE);
548         if (break_msg == NULL) {
549                 exit_server("Could not talloc break_msg\n");
550         }
551
552         /* Need to wait before sending a break message if we sent ourselves this message. */
553         if (procid_to_pid(&src) == sys_getpid()) {
554                 wait_before_sending_break();
555         }
556
557         /* Save the server smb signing state. */
558         sign_state = srv_oplock_set_signing(False);
559
560         show_msg(break_msg);
561         if (!srv_send_smb(smbd_server_fd(),
562                         break_msg,
563                         IS_CONN_ENCRYPTED(fsp->conn))) {
564                 exit_server_cleanly("oplock_break: srv_send_smb failed.");
565         }
566
567         /* Restore the sign state to what it was. */
568         srv_oplock_set_signing(sign_state);
569
570         TALLOC_FREE(break_msg);
571
572         fsp->sent_oplock_break = break_to_level2 ? LEVEL_II_BREAK_SENT:BREAK_TO_NONE_SENT;
573
574         msg.pid = src;
575         ADD_TO_ARRAY(NULL, struct share_mode_entry, msg,
576                      &fsp->pending_break_messages,
577                      &fsp->num_pending_break_messages);
578
579         add_oplock_timeout_handler(fsp);
580 }
581
582 /*******************************************************************
583  This handles the kernel oplock break message.
584 *******************************************************************/
585
586 static void process_kernel_oplock_break(struct messaging_context *msg_ctx,
587                                         void *private_data,
588                                         uint32_t msg_type,
589                                         struct server_id src,
590                                         DATA_BLOB *data)
591 {
592         struct file_id id;
593         unsigned long file_id;
594         files_struct *fsp;
595         char *break_msg;
596         bool sign_state;
597
598         if (data->data == NULL) {
599                 DEBUG(0, ("Got NULL buffer\n"));
600                 return;
601         }
602
603         if (data->length != MSG_SMB_KERNEL_BREAK_SIZE) {
604                 DEBUG(0, ("Got invalid msg len %d\n", (int)data->length));
605                 return;
606         }
607
608         /* Pull the data from the message. */
609         pull_file_id_16((char *)data->data, &id);
610         file_id = (unsigned long)IVAL(data->data, 16);
611
612         DEBUG(10, ("Got kernel oplock break message from pid %d: %s/%u\n",
613                    (int)procid_to_pid(&src), file_id_string_tos(&id),
614                    (unsigned int)file_id));
615
616         fsp = initial_break_processing(id, file_id);
617
618         if (fsp == NULL) {
619                 DEBUG(3, ("Got a kernel oplock break message for a file "
620                           "I don't know about\n"));
621                 return;
622         }
623
624         if (fsp->sent_oplock_break != NO_BREAK_SENT) {
625                 /* This is ok, kernel oplocks come in completely async */
626                 DEBUG(3, ("Got a kernel oplock request while waiting for a "
627                           "break reply\n"));
628                 return;
629         }
630
631         break_msg = new_break_smb_message(NULL, fsp, OPLOCKLEVEL_NONE);
632         if (break_msg == NULL) {
633                 exit_server("Could not talloc break_msg\n");
634         }
635
636         /* Save the server smb signing state. */
637         sign_state = srv_oplock_set_signing(False);
638
639         show_msg(break_msg);
640         if (!srv_send_smb(smbd_server_fd(),
641                         break_msg,
642                         IS_CONN_ENCRYPTED(fsp->conn))) {
643                 exit_server_cleanly("oplock_break: srv_send_smb failed.");
644         }
645
646         /* Restore the sign state to what it was. */
647         srv_oplock_set_signing(sign_state);
648
649         TALLOC_FREE(break_msg);
650
651         fsp->sent_oplock_break = BREAK_TO_NONE_SENT;
652
653         add_oplock_timeout_handler(fsp);
654 }
655
656 void reply_to_oplock_break_requests(files_struct *fsp)
657 {
658         int i;
659
660         for (i=0; i<fsp->num_pending_break_messages; i++) {
661                 struct share_mode_entry *e = &fsp->pending_break_messages[i];
662                 char msg[MSG_SMB_SHARE_MODE_ENTRY_SIZE];
663
664                 share_mode_entry_to_message(msg, e);
665
666                 messaging_send_buf(smbd_messaging_context(), e->pid,
667                                    MSG_SMB_BREAK_RESPONSE,
668                                    (uint8 *)msg,
669                                    MSG_SMB_SHARE_MODE_ENTRY_SIZE);
670         }
671
672         SAFE_FREE(fsp->pending_break_messages);
673         fsp->num_pending_break_messages = 0;
674         if (fsp->oplock_timeout != NULL) {
675                 /* Remove the timed event handler. */
676                 TALLOC_FREE(fsp->oplock_timeout);
677                 fsp->oplock_timeout = NULL;
678         }
679         return;
680 }
681
682 static void process_oplock_break_response(struct messaging_context *msg_ctx,
683                                           void *private_data,
684                                           uint32_t msg_type,
685                                           struct server_id src,
686                                           DATA_BLOB *data)
687 {
688         struct share_mode_entry msg;
689
690         if (data->data == NULL) {
691                 DEBUG(0, ("Got NULL buffer\n"));
692                 return;
693         }
694
695         if (data->length != MSG_SMB_SHARE_MODE_ENTRY_SIZE) {
696                 DEBUG(0, ("Got invalid msg len %u\n",
697                           (unsigned int)data->length));
698                 return;
699         }
700
701         /* De-linearize incoming message. */
702         message_to_share_mode_entry(&msg, (char *)data->data);
703
704         DEBUG(10, ("Got oplock break response from pid %d: %s/%lu mid %u\n",
705                    (int)procid_to_pid(&src), file_id_string_tos(&msg.id), msg.share_file_id,
706                    (unsigned int)msg.op_mid));
707
708         /* Here's the hack from open.c, store the mid in the 'port' field */
709         schedule_deferred_open_smb_message(msg.op_mid);
710 }
711
712 static void process_open_retry_message(struct messaging_context *msg_ctx,
713                                        void *private_data,
714                                        uint32_t msg_type,
715                                        struct server_id src,
716                                        DATA_BLOB *data)
717 {
718         struct share_mode_entry msg;
719         
720         if (data->data == NULL) {
721                 DEBUG(0, ("Got NULL buffer\n"));
722                 return;
723         }
724
725         if (data->length != MSG_SMB_SHARE_MODE_ENTRY_SIZE) {
726                 DEBUG(0, ("Got invalid msg len %d\n", (int)data->length));
727                 return;
728         }
729
730         /* De-linearize incoming message. */
731         message_to_share_mode_entry(&msg, (char *)data->data);
732
733         DEBUG(10, ("Got open retry msg from pid %d: %s mid %u\n",
734                    (int)procid_to_pid(&src), file_id_string_tos(&msg.id),
735                    (unsigned int)msg.op_mid));
736
737         schedule_deferred_open_smb_message(msg.op_mid);
738 }
739
740 /****************************************************************************
741  This function is called on any file modification or lock request. If a file
742  is level 2 oplocked then it must tell all other level 2 holders to break to
743  none.
744 ****************************************************************************/
745
746 void release_level_2_oplocks_on_change(files_struct *fsp)
747 {
748         int i;
749         struct share_mode_lock *lck;
750
751         /*
752          * If this file is level II oplocked then we need
753          * to grab the shared memory lock and inform all
754          * other files with a level II lock that they need
755          * to flush their read caches. We keep the lock over
756          * the shared memory area whilst doing this.
757          */
758
759         if (!LEVEL_II_OPLOCK_TYPE(fsp->oplock_type))
760                 return;
761
762         lck = get_share_mode_lock(talloc_tos(), fsp->file_id, NULL, NULL,
763                                   NULL);
764         if (lck == NULL) {
765                 DEBUG(0,("release_level_2_oplocks_on_change: failed to lock "
766                          "share mode entry for file %s.\n", fsp->fsp_name ));
767                 return;
768         }
769
770         DEBUG(10,("release_level_2_oplocks_on_change: num_share_modes = %d\n", 
771                   lck->num_share_modes ));
772
773         for(i = 0; i < lck->num_share_modes; i++) {
774                 struct share_mode_entry *share_entry = &lck->share_modes[i];
775                 char msg[MSG_SMB_SHARE_MODE_ENTRY_SIZE];
776
777                 if (!is_valid_share_mode_entry(share_entry)) {
778                         continue;
779                 }
780
781                 /*
782                  * As there could have been multiple writes waiting at the
783                  * lock_share_entry gate we may not be the first to
784                  * enter. Hence the state of the op_types in the share mode
785                  * entries may be partly NO_OPLOCK and partly LEVEL_II or FAKE_LEVEL_II
786                  * oplock. It will do no harm to re-send break messages to
787                  * those smbd's that are still waiting their turn to remove
788                  * their LEVEL_II state, and also no harm to ignore existing
789                  * NO_OPLOCK states. JRA.
790                  */
791
792                 DEBUG(10,("release_level_2_oplocks_on_change: "
793                           "share_entry[%i]->op_type == %d\n",
794                           i, share_entry->op_type ));
795
796                 if (share_entry->op_type == NO_OPLOCK) {
797                         continue;
798                 }
799
800                 /* Paranoia .... */
801                 if (EXCLUSIVE_OPLOCK_TYPE(share_entry->op_type)) {
802                         DEBUG(0,("release_level_2_oplocks_on_change: PANIC. "
803                                  "share mode entry %d is an exlusive "
804                                  "oplock !\n", i ));
805                         TALLOC_FREE(lck);
806                         abort();
807                 }
808
809                 share_mode_entry_to_message(msg, share_entry);
810
811                 messaging_send_buf(smbd_messaging_context(), share_entry->pid,
812                                    MSG_SMB_ASYNC_LEVEL2_BREAK,
813                                    (uint8 *)msg,
814                                    MSG_SMB_SHARE_MODE_ENTRY_SIZE);
815         }
816
817         /* We let the message receivers handle removing the oplock state
818            in the share mode lock db. */
819
820         TALLOC_FREE(lck);
821 }
822
823 /****************************************************************************
824  Linearize a share mode entry struct to an internal oplock break message.
825 ****************************************************************************/
826
827 void share_mode_entry_to_message(char *msg, const struct share_mode_entry *e)
828 {
829         SIVAL(msg,0,(uint32)e->pid.pid);
830         SSVAL(msg,4,e->op_mid);
831         SSVAL(msg,6,e->op_type);
832         SIVAL(msg,8,e->access_mask);
833         SIVAL(msg,12,e->share_access);
834         SIVAL(msg,16,e->private_options);
835         SIVAL(msg,20,(uint32)e->time.tv_sec);
836         SIVAL(msg,24,(uint32)e->time.tv_usec);
837         push_file_id_16(msg+28, &e->id);
838         SIVAL(msg,44,e->share_file_id);
839         SIVAL(msg,48,e->uid);
840         SSVAL(msg,52,e->flags);
841 #ifdef CLUSTER_SUPPORT
842         SIVAL(msg,54,e->pid.vnn);
843 #endif
844 }
845
846 /****************************************************************************
847  De-linearize an internal oplock break message to a share mode entry struct.
848 ****************************************************************************/
849
850 void message_to_share_mode_entry(struct share_mode_entry *e, char *msg)
851 {
852         e->pid.pid = (pid_t)IVAL(msg,0);
853         e->op_mid = SVAL(msg,4);
854         e->op_type = SVAL(msg,6);
855         e->access_mask = IVAL(msg,8);
856         e->share_access = IVAL(msg,12);
857         e->private_options = IVAL(msg,16);
858         e->time.tv_sec = (time_t)IVAL(msg,20);
859         e->time.tv_usec = (int)IVAL(msg,24);
860         pull_file_id_16(msg+28, &e->id);
861         e->share_file_id = (unsigned long)IVAL(msg,44);
862         e->uid = (uint32)IVAL(msg,48);
863         e->flags = (uint16)SVAL(msg,52);
864 #ifdef CLUSTER_SUPPORT
865         e->pid.vnn = IVAL(msg,54);
866 #endif
867 }
868
869 /****************************************************************************
870  Setup oplocks for this process.
871 ****************************************************************************/
872
873 bool init_oplocks(struct messaging_context *msg_ctx)
874 {
875         DEBUG(3,("init_oplocks: initializing messages.\n"));
876
877         messaging_register(msg_ctx, NULL, MSG_SMB_BREAK_REQUEST,
878                            process_oplock_break_message);
879         messaging_register(msg_ctx, NULL, MSG_SMB_ASYNC_LEVEL2_BREAK,
880                            process_oplock_async_level2_break_message);
881         messaging_register(msg_ctx, NULL, MSG_SMB_BREAK_RESPONSE,
882                            process_oplock_break_response);
883         messaging_register(msg_ctx, NULL, MSG_SMB_KERNEL_BREAK,
884                            process_kernel_oplock_break);
885         messaging_register(msg_ctx, NULL, MSG_SMB_OPEN_RETRY,
886                            process_open_retry_message);
887
888         if (lp_kernel_oplocks()) {
889 #if HAVE_KERNEL_OPLOCKS_IRIX
890                 koplocks = irix_init_kernel_oplocks();
891 #elif HAVE_KERNEL_OPLOCKS_LINUX
892                 koplocks = linux_init_kernel_oplocks();
893 #endif
894         }
895
896         return True;
897 }