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s4:rootdse LDB module - remove unused variable
[Samba/gebeck_regimport.git] / source3 / lib / dbwrap_ctdb.c
blob67425dcb7901b9004474d23a415ce69b88f9649e
1 /*
2 Unix SMB/CIFS implementation.
3 Database interface wrapper around ctdbd
4 Copyright (C) Volker Lendecke 2007-2009
5 Copyright (C) Michael Adam 2009
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
19 */
20
21 #include "includes.h"
22 #ifdef CLUSTER_SUPPORT
23 #include "ctdb.h"
24 #include "ctdb_private.h"
25 #include "ctdbd_conn.h"
26 #include "g_lock.h"
27
28 struct db_ctdb_transaction_handle {
29 struct db_ctdb_ctx *ctx;
30 /*
31 * we store the reads and writes done under a transaction:
32 * - one list stores both reads and writes (m_all),
33 * - the other just writes (m_write)
34 */
35 struct ctdb_marshall_buffer *m_all;
36 struct ctdb_marshall_buffer *m_write;
37 uint32_t nesting;
38 bool nested_cancel;
39 char *lock_name;
40 };
41
42 struct db_ctdb_ctx {
43 struct db_context *db;
44 struct tdb_wrap *wtdb;
45 uint32 db_id;
46 struct db_ctdb_transaction_handle *transaction;
47 struct g_lock_ctx *lock_ctx;
48 };
49
50 struct db_ctdb_rec {
51 struct db_ctdb_ctx *ctdb_ctx;
52 struct ctdb_ltdb_header header;
53 struct timeval lock_time;
54 };
55
56 static NTSTATUS tdb_error_to_ntstatus(struct tdb_context *tdb)
57 {
58 NTSTATUS status;
59 enum TDB_ERROR tret = tdb_error(tdb);
60
61 switch (tret) {
62 case TDB_ERR_EXISTS:
63 status = NT_STATUS_OBJECT_NAME_COLLISION;
64 break;
65 case TDB_ERR_NOEXIST:
66 status = NT_STATUS_OBJECT_NAME_NOT_FOUND;
67 break;
68 default:
69 status = NT_STATUS_INTERNAL_DB_CORRUPTION;
70 break;
71 }
72
73 return status;
74 }
75
76
77 /**
78 * fetch a record from the tdb, separating out the header
79 * information and returning the body of the record.
80 */
81 static NTSTATUS db_ctdb_ltdb_fetch(struct db_ctdb_ctx *db,
82 TDB_DATA key,
83 struct ctdb_ltdb_header *header,
84 TALLOC_CTX *mem_ctx,
85 TDB_DATA *data)
86 {
87 TDB_DATA rec;
88 NTSTATUS status;
89
90 rec = tdb_fetch(db->wtdb->tdb, key);
91 if (rec.dsize < sizeof(struct ctdb_ltdb_header)) {
92 status = NT_STATUS_NOT_FOUND;
93 if (data) {
94 ZERO_STRUCTP(data);
95 }
96 if (header) {
97 header->dmaster = (uint32_t)-1;
98 header->rsn = 0;
99 }
100 goto done;
101 }
102
103 if (header) {
104 *header = *(struct ctdb_ltdb_header *)rec.dptr;
105 }
106
107 if (data) {
108 data->dsize = rec.dsize - sizeof(struct ctdb_ltdb_header);
109 if (data->dsize == 0) {
110 data->dptr = NULL;
111 } else {
112 data->dptr = (unsigned char *)talloc_memdup(mem_ctx,
113 rec.dptr
114 + sizeof(struct ctdb_ltdb_header),
115 data->dsize);
116 if (data->dptr == NULL) {
117 status = NT_STATUS_NO_MEMORY;
118 goto done;
119 }
120 }
121 }
122
123 status = NT_STATUS_OK;
124
125 done:
126 SAFE_FREE(rec.dptr);
127 return status;
128 }
129
130 /*
131 * Store a record together with the ctdb record header
132 * in the local copy of the database.
133 */
134 static NTSTATUS db_ctdb_ltdb_store(struct db_ctdb_ctx *db,
135 TDB_DATA key,
136 struct ctdb_ltdb_header *header,
137 TDB_DATA data)
138 {
139 TALLOC_CTX *tmp_ctx = talloc_stackframe();
140 TDB_DATA rec;
141 int ret;
142
143 rec.dsize = data.dsize + sizeof(struct ctdb_ltdb_header);
144 rec.dptr = (uint8_t *)talloc_size(tmp_ctx, rec.dsize);
145
146 if (rec.dptr == NULL) {
147 talloc_free(tmp_ctx);
148 return NT_STATUS_NO_MEMORY;
149 }
150
151 memcpy(rec.dptr, header, sizeof(struct ctdb_ltdb_header));
152 memcpy(sizeof(struct ctdb_ltdb_header) + (uint8_t *)rec.dptr, data.dptr, data.dsize);
153
154 ret = tdb_store(db->wtdb->tdb, key, rec, TDB_REPLACE);
155
156 talloc_free(tmp_ctx);
157
158 return (ret == 0) ? NT_STATUS_OK
159 : tdb_error_to_ntstatus(db->wtdb->tdb);
160
161 }
162
163 /*
164 form a ctdb_rec_data record from a key/data pair
165
166 note that header may be NULL. If not NULL then it is included in the data portion
167 of the record
168 */
169 static struct ctdb_rec_data *db_ctdb_marshall_record(TALLOC_CTX *mem_ctx, uint32_t reqid,
170 TDB_DATA key,
171 struct ctdb_ltdb_header *header,
172 TDB_DATA data)
173 {
174 size_t length;
175 struct ctdb_rec_data *d;
176
177 length = offsetof(struct ctdb_rec_data, data) + key.dsize +
178 data.dsize + (header?sizeof(*header):0);
179 d = (struct ctdb_rec_data *)talloc_size(mem_ctx, length);
180 if (d == NULL) {
181 return NULL;
182 }
183 d->length = length;
184 d->reqid = reqid;
185 d->keylen = key.dsize;
186 memcpy(&d->data[0], key.dptr, key.dsize);
187 if (header) {
188 d->datalen = data.dsize + sizeof(*header);
189 memcpy(&d->data[key.dsize], header, sizeof(*header));
190 memcpy(&d->data[key.dsize+sizeof(*header)], data.dptr, data.dsize);
191 } else {
192 d->datalen = data.dsize;
193 memcpy(&d->data[key.dsize], data.dptr, data.dsize);
194 }
195 return d;
196 }
197
198
199 /* helper function for marshalling multiple records */
200 static struct ctdb_marshall_buffer *db_ctdb_marshall_add(TALLOC_CTX *mem_ctx,
201 struct ctdb_marshall_buffer *m,
202 uint64_t db_id,
203 uint32_t reqid,
204 TDB_DATA key,
205 struct ctdb_ltdb_header *header,
206 TDB_DATA data)
207 {
208 struct ctdb_rec_data *r;
209 size_t m_size, r_size;
210 struct ctdb_marshall_buffer *m2 = NULL;
211
212 r = db_ctdb_marshall_record(talloc_tos(), reqid, key, header, data);
213 if (r == NULL) {
214 talloc_free(m);
215 return NULL;
216 }
217
218 if (m == NULL) {
219 m = (struct ctdb_marshall_buffer *)talloc_zero_size(
220 mem_ctx, offsetof(struct ctdb_marshall_buffer, data));
221 if (m == NULL) {
222 goto done;
223 }
224 m->db_id = db_id;
225 }
226
227 m_size = talloc_get_size(m);
228 r_size = talloc_get_size(r);
229
230 m2 = (struct ctdb_marshall_buffer *)talloc_realloc_size(
231 mem_ctx, m, m_size + r_size);
232 if (m2 == NULL) {
233 talloc_free(m);
234 goto done;
235 }
236
237 memcpy(m_size + (uint8_t *)m2, r, r_size);
238
239 m2->count++;
240
241 done:
242 talloc_free(r);
243 return m2;
244 }
245
246 /* we've finished marshalling, return a data blob with the marshalled records */
247 static TDB_DATA db_ctdb_marshall_finish(struct ctdb_marshall_buffer *m)
248 {
249 TDB_DATA data;
250 data.dptr = (uint8_t *)m;
251 data.dsize = talloc_get_size(m);
252 return data;
253 }
254
255 /*
256 loop over a marshalling buffer
257
258 - pass r==NULL to start
259 - loop the number of times indicated by m->count
260 */
261 static struct ctdb_rec_data *db_ctdb_marshall_loop_next(struct ctdb_marshall_buffer *m, struct ctdb_rec_data *r,
262 uint32_t *reqid,
263 struct ctdb_ltdb_header *header,
264 TDB_DATA *key, TDB_DATA *data)
265 {
266 if (r == NULL) {
267 r = (struct ctdb_rec_data *)&m->data[0];
268 } else {
269 r = (struct ctdb_rec_data *)(r->length + (uint8_t *)r);
270 }
271
272 if (reqid != NULL) {
273 *reqid = r->reqid;
274 }
275
276 if (key != NULL) {
277 key->dptr = &r->data[0];
278 key->dsize = r->keylen;
279 }
280 if (data != NULL) {
281 data->dptr = &r->data[r->keylen];
282 data->dsize = r->datalen;
283 if (header != NULL) {
284 data->dptr += sizeof(*header);
285 data->dsize -= sizeof(*header);
286 }
287 }
288
289 if (header != NULL) {
290 if (r->datalen < sizeof(*header)) {
291 return NULL;
292 }
293 *header = *(struct ctdb_ltdb_header *)&r->data[r->keylen];
294 }
295
296 return r;
297 }
298
299 /**
300 * CTDB transaction destructor
301 */
302 static int db_ctdb_transaction_destructor(struct db_ctdb_transaction_handle *h)
303 {
304 NTSTATUS status;
305
306 status = g_lock_unlock(h->ctx->lock_ctx, h->lock_name);
307 if (!NT_STATUS_IS_OK(status)) {
308 DEBUG(0, ("g_lock_unlock failed: %s\n", nt_errstr(status)));
309 return -1;
310 }
311 return 0;
312 }
313
314 /**
315 * CTDB dbwrap API: transaction_start function
316 * starts a transaction on a persistent database
317 */
318 static int db_ctdb_transaction_start(struct db_context *db)
319 {
320 struct db_ctdb_transaction_handle *h;
321 NTSTATUS status;
322 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
323 struct db_ctdb_ctx);
324
325 if (!db->persistent) {
326 DEBUG(0,("transactions not supported on non-persistent database 0x%08x\n",
327 ctx->db_id));
328 return -1;
329 }
330
331 if (ctx->transaction) {
332 ctx->transaction->nesting++;
333 return 0;
334 }
335
336 h = talloc_zero(db, struct db_ctdb_transaction_handle);
337 if (h == NULL) {
338 DEBUG(0,(__location__ " oom for transaction handle\n"));
339 return -1;
340 }
341
342 h->ctx = ctx;
343
344 h->lock_name = talloc_asprintf(h, "transaction_db_0x%08x",
345 (unsigned int)ctx->db_id);
346 if (h->lock_name == NULL) {
347 DEBUG(0, ("talloc_asprintf failed\n"));
348 TALLOC_FREE(h);
349 return -1;
350 }
351
352 /*
353 * Wait a day, i.e. forever...
354 */
355 status = g_lock_lock(ctx->lock_ctx, h->lock_name, G_LOCK_WRITE,
356 timeval_set(86400, 0));
357 if (!NT_STATUS_IS_OK(status)) {
358 DEBUG(0, ("g_lock_lock failed: %s\n", nt_errstr(status)));
359 TALLOC_FREE(h);
360 return -1;
361 }
362
363 talloc_set_destructor(h, db_ctdb_transaction_destructor);
364
365 ctx->transaction = h;
366
367 DEBUG(5,(__location__ " Started transaction on db 0x%08x\n", ctx->db_id));
368
369 return 0;
370 }
371
372 static bool pull_newest_from_marshall_buffer(struct ctdb_marshall_buffer *buf,
373 TDB_DATA key,
374 struct ctdb_ltdb_header *pheader,
375 TALLOC_CTX *mem_ctx,
376 TDB_DATA *pdata)
377 {
378 struct ctdb_rec_data *rec = NULL;
379 struct ctdb_ltdb_header h;
380 bool found = false;
381 TDB_DATA data;
382 int i;
383
384 if (buf == NULL) {
385 return false;
386 }
387
388 ZERO_STRUCT(h);
389 ZERO_STRUCT(data);
390
391 /*
392 * Walk the list of records written during this
393 * transaction. If we want to read one we have already
394 * written, return the last written sample. Thus we do not do
395 * a "break;" for the first hit, this record might have been
396 * overwritten later.
397 */
398
399 for (i=0; i<buf->count; i++) {
400 TDB_DATA tkey, tdata;
401 uint32_t reqid;
402 struct ctdb_ltdb_header hdr;
403
404 ZERO_STRUCT(hdr);
405
406 rec = db_ctdb_marshall_loop_next(buf, rec, &reqid, &hdr, &tkey,
407 &tdata);
408 if (rec == NULL) {
409 return false;
410 }
411
412 if (tdb_data_equal(key, tkey)) {
413 found = true;
414 data = tdata;
415 h = hdr;
416 }
417 }
418
419 if (!found) {
420 return false;
421 }
422
423 if (pdata != NULL) {
424 data.dptr = (uint8_t *)talloc_memdup(mem_ctx, data.dptr,
425 data.dsize);
426 if ((data.dsize != 0) && (data.dptr == NULL)) {
427 return false;
428 }
429 *pdata = data;
430 }
431
432 if (pheader != NULL) {
433 *pheader = h;
434 }
435
436 return true;
437 }
438
439 /*
440 fetch a record inside a transaction
441 */
442 static int db_ctdb_transaction_fetch(struct db_ctdb_ctx *db,
443 TALLOC_CTX *mem_ctx,
444 TDB_DATA key, TDB_DATA *data)
445 {
446 struct db_ctdb_transaction_handle *h = db->transaction;
447 NTSTATUS status;
448 bool found;
449
450 found = pull_newest_from_marshall_buffer(h->m_write, key, NULL,
451 mem_ctx, data);
452 if (found) {
453 return 0;
454 }
455
456 status = db_ctdb_ltdb_fetch(h->ctx, key, NULL, mem_ctx, data);
457
458 if (NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND)) {
459 *data = tdb_null;
460 } else if (!NT_STATUS_IS_OK(status)) {
461 return -1;
462 }
463
464 h->m_all = db_ctdb_marshall_add(h, h->m_all, h->ctx->db_id, 1, key,
465 NULL, *data);
466 if (h->m_all == NULL) {
467 DEBUG(0,(__location__ " Failed to add to marshalling "
468 "record\n"));
469 data->dsize = 0;
470 talloc_free(data->dptr);
471 return -1;
472 }
473
474 return 0;
475 }
476
477
478 static NTSTATUS db_ctdb_store_transaction(struct db_record *rec, TDB_DATA data, int flag);
479 static NTSTATUS db_ctdb_delete_transaction(struct db_record *rec);
480
481 static struct db_record *db_ctdb_fetch_locked_transaction(struct db_ctdb_ctx *ctx,
482 TALLOC_CTX *mem_ctx,
483 TDB_DATA key)
484 {
485 struct db_record *result;
486 TDB_DATA ctdb_data;
487
488 if (!(result = talloc(mem_ctx, struct db_record))) {
489 DEBUG(0, ("talloc failed\n"));
490 return NULL;
491 }
492
493 result->private_data = ctx->transaction;
494
495 result->key.dsize = key.dsize;
496 result->key.dptr = (uint8 *)talloc_memdup(result, key.dptr, key.dsize);
497 if (result->key.dptr == NULL) {
498 DEBUG(0, ("talloc failed\n"));
499 TALLOC_FREE(result);
500 return NULL;
501 }
502
503 result->store = db_ctdb_store_transaction;
504 result->delete_rec = db_ctdb_delete_transaction;
505
506 if (pull_newest_from_marshall_buffer(ctx->transaction->m_write, key,
507 NULL, result, &result->value)) {
508 return result;
509 }
510
511 ctdb_data = tdb_fetch(ctx->wtdb->tdb, key);
512 if (ctdb_data.dptr == NULL) {
513 /* create the record */
514 result->value = tdb_null;
515 return result;
516 }
517
518 result->value.dsize = ctdb_data.dsize - sizeof(struct ctdb_ltdb_header);
519 result->value.dptr = NULL;
520
521 if ((result->value.dsize != 0)
522 && !(result->value.dptr = (uint8 *)talloc_memdup(
523 result, ctdb_data.dptr + sizeof(struct ctdb_ltdb_header),
524 result->value.dsize))) {
525 DEBUG(0, ("talloc failed\n"));
526 TALLOC_FREE(result);
527 }
528
529 SAFE_FREE(ctdb_data.dptr);
530
531 return result;
532 }
533
534 static int db_ctdb_record_destructor(struct db_record **recp)
535 {
536 struct db_record *rec = talloc_get_type_abort(*recp, struct db_record);
537 struct db_ctdb_transaction_handle *h = talloc_get_type_abort(
538 rec->private_data, struct db_ctdb_transaction_handle);
539 int ret = h->ctx->db->transaction_commit(h->ctx->db);
540 if (ret != 0) {
541 DEBUG(0,(__location__ " transaction_commit failed\n"));
542 }
543 return 0;
544 }
545
546 /*
547 auto-create a transaction for persistent databases
548 */
549 static struct db_record *db_ctdb_fetch_locked_persistent(struct db_ctdb_ctx *ctx,
550 TALLOC_CTX *mem_ctx,
551 TDB_DATA key)
552 {
553 int res;
554 struct db_record *rec, **recp;
555
556 res = db_ctdb_transaction_start(ctx->db);
557 if (res == -1) {
558 return NULL;
559 }
560
561 rec = db_ctdb_fetch_locked_transaction(ctx, mem_ctx, key);
562 if (rec == NULL) {
563 ctx->db->transaction_cancel(ctx->db);
564 return NULL;
565 }
566
567 /* destroy this transaction when we release the lock */
568 recp = talloc(rec, struct db_record *);
569 if (recp == NULL) {
570 ctx->db->transaction_cancel(ctx->db);
571 talloc_free(rec);
572 return NULL;
573 }
574 *recp = rec;
575 talloc_set_destructor(recp, db_ctdb_record_destructor);
576 return rec;
577 }
578
579
580 /*
581 stores a record inside a transaction
582 */
583 static NTSTATUS db_ctdb_transaction_store(struct db_ctdb_transaction_handle *h,
584 TDB_DATA key, TDB_DATA data)
585 {
586 TALLOC_CTX *tmp_ctx = talloc_new(h);
587 TDB_DATA rec;
588 struct ctdb_ltdb_header header;
589
590 ZERO_STRUCT(header);
591
592 /* we need the header so we can update the RSN */
593
594 if (!pull_newest_from_marshall_buffer(h->m_write, key, &header,
595 NULL, NULL)) {
596
597 rec = tdb_fetch(h->ctx->wtdb->tdb, key);
598
599 if (rec.dptr != NULL) {
600 memcpy(&header, rec.dptr,
601 sizeof(struct ctdb_ltdb_header));
602 rec.dsize -= sizeof(struct ctdb_ltdb_header);
603
604 /*
605 * a special case, we are writing the same
606 * data that is there now
607 */
608 if (data.dsize == rec.dsize &&
609 memcmp(data.dptr,
610 rec.dptr + sizeof(struct ctdb_ltdb_header),
611 data.dsize) == 0) {
612 SAFE_FREE(rec.dptr);
613 talloc_free(tmp_ctx);
614 return NT_STATUS_OK;
615 }
616 }
617 SAFE_FREE(rec.dptr);
618 }
619
620 header.dmaster = get_my_vnn();
621 header.rsn++;
622
623 h->m_all = db_ctdb_marshall_add(h, h->m_all, h->ctx->db_id, 0, key,
624 NULL, data);
625 if (h->m_all == NULL) {
626 DEBUG(0,(__location__ " Failed to add to marshalling "
627 "record\n"));
628 talloc_free(tmp_ctx);
629 return NT_STATUS_NO_MEMORY;
630 }
631
632 h->m_write = db_ctdb_marshall_add(h, h->m_write, h->ctx->db_id, 0, key, &header, data);
633 if (h->m_write == NULL) {
634 DEBUG(0,(__location__ " Failed to add to marshalling record\n"));
635 talloc_free(tmp_ctx);
636 return NT_STATUS_NO_MEMORY;
637 }
638
639 talloc_free(tmp_ctx);
640 return NT_STATUS_OK;
641 }
642
643
644 /*
645 a record store inside a transaction
646 */
647 static NTSTATUS db_ctdb_store_transaction(struct db_record *rec, TDB_DATA data, int flag)
648 {
649 struct db_ctdb_transaction_handle *h = talloc_get_type_abort(
650 rec->private_data, struct db_ctdb_transaction_handle);
651 NTSTATUS status;
652
653 status = db_ctdb_transaction_store(h, rec->key, data);
654 return status;
655 }
656
657 /*
658 a record delete inside a transaction
659 */
660 static NTSTATUS db_ctdb_delete_transaction(struct db_record *rec)
661 {
662 struct db_ctdb_transaction_handle *h = talloc_get_type_abort(
663 rec->private_data, struct db_ctdb_transaction_handle);
664 NTSTATUS status;
665
666 status = db_ctdb_transaction_store(h, rec->key, tdb_null);
667 return status;
668 }
669
670 /**
671 * Fetch the db sequence number of a persistent db directly from the db.
672 */
673 static NTSTATUS db_ctdb_fetch_db_seqnum_from_db(struct db_ctdb_ctx *db,
674 uint64_t *seqnum)
675 {
676 NTSTATUS status;
677 const char *keyname = CTDB_DB_SEQNUM_KEY;
678 TDB_DATA key;
679 TDB_DATA data;
680 struct ctdb_ltdb_header header;
681 TALLOC_CTX *mem_ctx = talloc_stackframe();
682
683 if (seqnum == NULL) {
684 return NT_STATUS_INVALID_PARAMETER;
685 }
686
687 key = string_term_tdb_data(keyname);
688
689 status = db_ctdb_ltdb_fetch(db, key, &header, mem_ctx, &data);
690 if (!NT_STATUS_IS_OK(status) &&
691 !NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND))
692 {
693 goto done;
694 }
695
696 status = NT_STATUS_OK;
697
698 if (data.dsize != sizeof(uint64_t)) {
699 *seqnum = 0;
700 goto done;
701 }
702
703 *seqnum = *(uint64_t *)data.dptr;
704
705 done:
706 TALLOC_FREE(mem_ctx);
707 return status;
708 }
709
710 /**
711 * Store the database sequence number inside a transaction.
712 */
713 static NTSTATUS db_ctdb_store_db_seqnum(struct db_ctdb_transaction_handle *h,
714 uint64_t seqnum)
715 {
716 NTSTATUS status;
717 const char *keyname = CTDB_DB_SEQNUM_KEY;
718 TDB_DATA key;
719 TDB_DATA data;
720
721 key = string_term_tdb_data(keyname);
722
723 data.dptr = (uint8_t *)&seqnum;
724 data.dsize = sizeof(uint64_t);
725
726 status = db_ctdb_transaction_store(h, key, data);
727
728 return status;
729 }
730
731 /*
732 commit a transaction
733 */
734 static int db_ctdb_transaction_commit(struct db_context *db)
735 {
736 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
737 struct db_ctdb_ctx);
738 NTSTATUS rets;
739 int status;
740 struct db_ctdb_transaction_handle *h = ctx->transaction;
741 uint64_t old_seqnum, new_seqnum;
742 int ret;
743
744 if (h == NULL) {
745 DEBUG(0,(__location__ " transaction commit with no open transaction on db 0x%08x\n", ctx->db_id));
746 return -1;
747 }
748
749 if (h->nested_cancel) {
750 db->transaction_cancel(db);
751 DEBUG(5,(__location__ " Failed transaction commit after nested cancel\n"));
752 return -1;
753 }
754
755 if (h->nesting != 0) {
756 h->nesting--;
757 return 0;
758 }
759
760 if (h->m_write == NULL) {
761 /*
762 * No changes were made, so don't change the seqnum,
763 * don't push to other node, just exit with success.
764 */
765 ret = 0;
766 goto done;
767 }
768
769 DEBUG(5,(__location__ " Commit transaction on db 0x%08x\n", ctx->db_id));
770
771 /*
772 * As the last db action before committing, bump the database sequence
773 * number. Note that this undoes all changes to the seqnum records
774 * performed under the transaction. This record is not meant to be
775 * modified by user interaction. It is for internal use only...
776 */
777 rets = db_ctdb_fetch_db_seqnum_from_db(ctx, &old_seqnum);
778 if (!NT_STATUS_IS_OK(rets)) {
779 DEBUG(1, (__location__ " failed to fetch the db sequence number "
780 "in transaction commit on db 0x%08x\n", ctx->db_id));
781 ret = -1;
782 goto done;
783 }
784
785 new_seqnum = old_seqnum + 1;
786
787 rets = db_ctdb_store_db_seqnum(h, new_seqnum);
788 if (!NT_STATUS_IS_OK(rets)) {
789 DEBUG(1, (__location__ "failed to store the db sequence number "
790 " in transaction commit on db 0x%08x\n", ctx->db_id));
791 ret = -1;
792 goto done;
793 }
794
795 again:
796 /* tell ctdbd to commit to the other nodes */
797 rets = ctdbd_control_local(messaging_ctdbd_connection(),
798 CTDB_CONTROL_TRANS3_COMMIT,
799 h->ctx->db_id, 0,
800 db_ctdb_marshall_finish(h->m_write),
801 NULL, NULL, &status);
802 if (!NT_STATUS_IS_OK(rets) || status != 0) {
803 /*
804 * The TRANS3_COMMIT control should only possibly fail when a
805 * recovery has been running concurrently. In any case, the db
806 * will be the same on all nodes, either the new copy or the
807 * old copy. This can be detected by comparing the old and new
808 * local sequence numbers.
809 */
810 rets = db_ctdb_fetch_db_seqnum_from_db(ctx, &new_seqnum);
811 if (!NT_STATUS_IS_OK(rets)) {
812 DEBUG(1, (__location__ " failed to refetch db sequence "
813 "number after failed TRANS3_COMMIT\n"));
814 ret = -1;
815 goto done;
816 }
817
818 if (new_seqnum == old_seqnum) {
819 /* Recovery prevented all our changes: retry. */
820 goto again;
821 } else if (new_seqnum != (old_seqnum + 1)) {
822 DEBUG(0, (__location__ " ERROR: new_seqnum[%lu] != "
823 "old_seqnum[%lu] + (0 or 1) after failed "
824 "TRANS3_COMMIT - this should not happen!\n",
825 (unsigned long)new_seqnum,
826 (unsigned long)old_seqnum));
827 ret = -1;
828 goto done;
829 }
830 /*
831 * Recovery propagated our changes to all nodes, completing
832 * our commit for us - succeed.
833 */
834 }
835
836 ret = 0;
837
838 done:
839 h->ctx->transaction = NULL;
840 talloc_free(h);
841 return ret;
842 }
843
844
845 /*
846 cancel a transaction
847 */
848 static int db_ctdb_transaction_cancel(struct db_context *db)
849 {
850 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
851 struct db_ctdb_ctx);
852 struct db_ctdb_transaction_handle *h = ctx->transaction;
853
854 if (h == NULL) {
855 DEBUG(0,(__location__ " transaction cancel with no open transaction on db 0x%08x\n", ctx->db_id));
856 return -1;
857 }
858
859 if (h->nesting != 0) {
860 h->nesting--;
861 h->nested_cancel = true;
862 return 0;
863 }
864
865 DEBUG(5,(__location__ " Cancel transaction on db 0x%08x\n", ctx->db_id));
866
867 ctx->transaction = NULL;
868 talloc_free(h);
869 return 0;
870 }
871
872
873 static NTSTATUS db_ctdb_store(struct db_record *rec, TDB_DATA data, int flag)
874 {
875 struct db_ctdb_rec *crec = talloc_get_type_abort(
876 rec->private_data, struct db_ctdb_rec);
877
878 return db_ctdb_ltdb_store(crec->ctdb_ctx, rec->key, &(crec->header), data);
879 }
880
881
882
883 static NTSTATUS db_ctdb_delete(struct db_record *rec)
884 {
885 TDB_DATA data;
886
887 /*
888 * We have to store the header with empty data. TODO: Fix the
889 * tdb-level cleanup
890 */
891
892 ZERO_STRUCT(data);
893
894 return db_ctdb_store(rec, data, 0);
895
896 }
897
898 static int db_ctdb_record_destr(struct db_record* data)
899 {
900 struct db_ctdb_rec *crec = talloc_get_type_abort(
901 data->private_data, struct db_ctdb_rec);
902 int threshold;
903
904 DEBUG(10, (DEBUGLEVEL > 10
905 ? "Unlocking db %u key %s\n"
906 : "Unlocking db %u key %.20s\n",
907 (int)crec->ctdb_ctx->db_id,
908 hex_encode_talloc(data, (unsigned char *)data->key.dptr,
909 data->key.dsize)));
910
911 if (tdb_chainunlock(crec->ctdb_ctx->wtdb->tdb, data->key) != 0) {
912 DEBUG(0, ("tdb_chainunlock failed\n"));
913 return -1;
914 }
915
916 threshold = lp_ctdb_locktime_warn_threshold();
917 if (threshold != 0) {
918 double timediff = timeval_elapsed(&crec->lock_time);
919 if ((timediff * 1000) > threshold) {
920 DEBUG(0, ("Held tdb lock %f seconds\n", timediff));
921 }
922 }
923
924 return 0;
925 }
926
927 static struct db_record *fetch_locked_internal(struct db_ctdb_ctx *ctx,
928 TALLOC_CTX *mem_ctx,
929 TDB_DATA key)
930 {
931 struct db_record *result;
932 struct db_ctdb_rec *crec;
933 NTSTATUS status;
934 TDB_DATA ctdb_data;
935 int migrate_attempts = 0;
936
937 if (!(result = talloc(mem_ctx, struct db_record))) {
938 DEBUG(0, ("talloc failed\n"));
939 return NULL;
940 }
941
942 if (!(crec = TALLOC_ZERO_P(result, struct db_ctdb_rec))) {
943 DEBUG(0, ("talloc failed\n"));
944 TALLOC_FREE(result);
945 return NULL;
946 }
947
948 result->private_data = (void *)crec;
949 crec->ctdb_ctx = ctx;
950
951 result->key.dsize = key.dsize;
952 result->key.dptr = (uint8 *)talloc_memdup(result, key.dptr, key.dsize);
953 if (result->key.dptr == NULL) {
954 DEBUG(0, ("talloc failed\n"));
955 TALLOC_FREE(result);
956 return NULL;
957 }
958
959 /*
960 * Do a blocking lock on the record
961 */
962 again:
963
964 if (DEBUGLEVEL >= 10) {
965 char *keystr = hex_encode_talloc(result, key.dptr, key.dsize);
966 DEBUG(10, (DEBUGLEVEL > 10
967 ? "Locking db %u key %s\n"
968 : "Locking db %u key %.20s\n",
969 (int)crec->ctdb_ctx->db_id, keystr));
970 TALLOC_FREE(keystr);
971 }
972
973 if (tdb_chainlock(ctx->wtdb->tdb, key) != 0) {
974 DEBUG(3, ("tdb_chainlock failed\n"));
975 TALLOC_FREE(result);
976 return NULL;
977 }
978
979 result->store = db_ctdb_store;
980 result->delete_rec = db_ctdb_delete;
981 talloc_set_destructor(result, db_ctdb_record_destr);
982
983 ctdb_data = tdb_fetch(ctx->wtdb->tdb, key);
984
985 /*
986 * See if we have a valid record and we are the dmaster. If so, we can
987 * take the shortcut and just return it.
988 */
989
990 if ((ctdb_data.dptr == NULL) ||
991 (ctdb_data.dsize < sizeof(struct ctdb_ltdb_header)) ||
992 ((struct ctdb_ltdb_header *)ctdb_data.dptr)->dmaster != get_my_vnn()
993 #if 0
994 || (random() % 2 != 0)
995 #endif
996 ) {
997 SAFE_FREE(ctdb_data.dptr);
998 tdb_chainunlock(ctx->wtdb->tdb, key);
999 talloc_set_destructor(result, NULL);
1000
1001 migrate_attempts += 1;
1002
1003 DEBUG(10, ("ctdb_data.dptr = %p, dmaster = %u (%u)\n",
1004 ctdb_data.dptr, ctdb_data.dptr ?
1005 ((struct ctdb_ltdb_header *)ctdb_data.dptr)->dmaster : -1,
1006 get_my_vnn()));
1007
1008 status = ctdbd_migrate(messaging_ctdbd_connection(), ctx->db_id,
1009 key);
1010 if (!NT_STATUS_IS_OK(status)) {
1011 DEBUG(5, ("ctdb_migrate failed: %s\n",
1012 nt_errstr(status)));
1013 TALLOC_FREE(result);
1014 return NULL;
1015 }
1016 /* now its migrated, try again */
1017 goto again;
1018 }
1019
1020 if (migrate_attempts > 10) {
1021 DEBUG(0, ("db_ctdb_fetch_locked needed %d attempts\n",
1022 migrate_attempts));
1023 }
1024
1025 GetTimeOfDay(&crec->lock_time);
1026
1027 memcpy(&crec->header, ctdb_data.dptr, sizeof(crec->header));
1028
1029 result->value.dsize = ctdb_data.dsize - sizeof(crec->header);
1030 result->value.dptr = NULL;
1031
1032 if ((result->value.dsize != 0)
1033 && !(result->value.dptr = (uint8 *)talloc_memdup(
1034 result, ctdb_data.dptr + sizeof(crec->header),
1035 result->value.dsize))) {
1036 DEBUG(0, ("talloc failed\n"));
1037 TALLOC_FREE(result);
1038 }
1039
1040 SAFE_FREE(ctdb_data.dptr);
1041
1042 return result;
1043 }
1044
1045 static struct db_record *db_ctdb_fetch_locked(struct db_context *db,
1046 TALLOC_CTX *mem_ctx,
1047 TDB_DATA key)
1048 {
1049 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
1050 struct db_ctdb_ctx);
1051
1052 if (ctx->transaction != NULL) {
1053 return db_ctdb_fetch_locked_transaction(ctx, mem_ctx, key);
1054 }
1055
1056 if (db->persistent) {
1057 return db_ctdb_fetch_locked_persistent(ctx, mem_ctx, key);
1058 }
1059
1060 return fetch_locked_internal(ctx, mem_ctx, key);
1061 }
1062
1063 /*
1064 fetch (unlocked, no migration) operation on ctdb
1065 */
1066 static int db_ctdb_fetch(struct db_context *db, TALLOC_CTX *mem_ctx,
1067 TDB_DATA key, TDB_DATA *data)
1068 {
1069 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
1070 struct db_ctdb_ctx);
1071 NTSTATUS status;
1072 TDB_DATA ctdb_data;
1073
1074 if (ctx->transaction) {
1075 return db_ctdb_transaction_fetch(ctx, mem_ctx, key, data);
1076 }
1077
1078 /* try a direct fetch */
1079 ctdb_data = tdb_fetch(ctx->wtdb->tdb, key);
1080
1081 /*
1082 * See if we have a valid record and we are the dmaster. If so, we can
1083 * take the shortcut and just return it.
1084 * we bypass the dmaster check for persistent databases
1085 */
1086 if ((ctdb_data.dptr != NULL) &&
1087 (ctdb_data.dsize >= sizeof(struct ctdb_ltdb_header)) &&
1088 (db->persistent ||
1089 ((struct ctdb_ltdb_header *)ctdb_data.dptr)->dmaster == get_my_vnn())) {
1090 /* we are the dmaster - avoid the ctdb protocol op */
1091
1092 data->dsize = ctdb_data.dsize - sizeof(struct ctdb_ltdb_header);
1093 if (data->dsize == 0) {
1094 SAFE_FREE(ctdb_data.dptr);
1095 data->dptr = NULL;
1096 return 0;
1097 }
1098
1099 data->dptr = (uint8 *)talloc_memdup(
1100 mem_ctx, ctdb_data.dptr+sizeof(struct ctdb_ltdb_header),
1101 data->dsize);
1102
1103 SAFE_FREE(ctdb_data.dptr);
1104
1105 if (data->dptr == NULL) {
1106 return -1;
1107 }
1108 return 0;
1109 }
1110
1111 SAFE_FREE(ctdb_data.dptr);
1112
1113 /* we weren't able to get it locally - ask ctdb to fetch it for us */
1114 status = ctdbd_fetch(messaging_ctdbd_connection(), ctx->db_id, key,
1115 mem_ctx, data);
1116 if (!NT_STATUS_IS_OK(status)) {
1117 DEBUG(5, ("ctdbd_fetch failed: %s\n", nt_errstr(status)));
1118 return -1;
1119 }
1120
1121 return 0;
1122 }
1123
1124 struct traverse_state {
1125 struct db_context *db;
1126 int (*fn)(struct db_record *rec, void *private_data);
1127 void *private_data;
1128 };
1129
1130 static void traverse_callback(TDB_DATA key, TDB_DATA data, void *private_data)
1131 {
1132 struct traverse_state *state = (struct traverse_state *)private_data;
1133 struct db_record *rec;
1134 TALLOC_CTX *tmp_ctx = talloc_new(state->db);
1135 /* we have to give them a locked record to prevent races */
1136 rec = db_ctdb_fetch_locked(state->db, tmp_ctx, key);
1137 if (rec && rec->value.dsize > 0) {
1138 state->fn(rec, state->private_data);
1139 }
1140 talloc_free(tmp_ctx);
1141 }
1142
1143 static int traverse_persistent_callback(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf,
1144 void *private_data)
1145 {
1146 struct traverse_state *state = (struct traverse_state *)private_data;
1147 struct db_record *rec;
1148 TALLOC_CTX *tmp_ctx = talloc_new(state->db);
1149 int ret = 0;
1150 /* we have to give them a locked record to prevent races */
1151 rec = db_ctdb_fetch_locked(state->db, tmp_ctx, kbuf);
1152 if (rec && rec->value.dsize > 0) {
1153 ret = state->fn(rec, state->private_data);
1154 }
1155 talloc_free(tmp_ctx);
1156 return ret;
1157 }
1158
1159 static int db_ctdb_traverse(struct db_context *db,
1160 int (*fn)(struct db_record *rec,
1161 void *private_data),
1162 void *private_data)
1163 {
1164 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
1165 struct db_ctdb_ctx);
1166 struct traverse_state state;
1167
1168 state.db = db;
1169 state.fn = fn;
1170 state.private_data = private_data;
1171
1172 if (db->persistent) {
1173 /* for persistent databases we don't need to do a ctdb traverse,
1174 we can do a faster local traverse */
1175 return tdb_traverse(ctx->wtdb->tdb, traverse_persistent_callback, &state);
1176 }
1177
1178
1179 ctdbd_traverse(ctx->db_id, traverse_callback, &state);
1180 return 0;
1181 }
1182
1183 static NTSTATUS db_ctdb_store_deny(struct db_record *rec, TDB_DATA data, int flag)
1184 {
1185 return NT_STATUS_MEDIA_WRITE_PROTECTED;
1186 }
1187
1188 static NTSTATUS db_ctdb_delete_deny(struct db_record *rec)
1189 {
1190 return NT_STATUS_MEDIA_WRITE_PROTECTED;
1191 }
1192
1193 static void traverse_read_callback(TDB_DATA key, TDB_DATA data, void *private_data)
1194 {
1195 struct traverse_state *state = (struct traverse_state *)private_data;
1196 struct db_record rec;
1197 rec.key = key;
1198 rec.value = data;
1199 rec.store = db_ctdb_store_deny;
1200 rec.delete_rec = db_ctdb_delete_deny;
1201 rec.private_data = state->db;
1202 state->fn(&rec, state->private_data);
1203 }
1204
1205 static int traverse_persistent_callback_read(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf,
1206 void *private_data)
1207 {
1208 struct traverse_state *state = (struct traverse_state *)private_data;
1209 struct db_record rec;
1210 rec.key = kbuf;
1211 rec.value = dbuf;
1212 rec.store = db_ctdb_store_deny;
1213 rec.delete_rec = db_ctdb_delete_deny;
1214 rec.private_data = state->db;
1215
1216 if (rec.value.dsize <= sizeof(struct ctdb_ltdb_header)) {
1217 /* a deleted record */
1218 return 0;
1219 }
1220 rec.value.dsize -= sizeof(struct ctdb_ltdb_header);
1221 rec.value.dptr += sizeof(struct ctdb_ltdb_header);
1222
1223 return state->fn(&rec, state->private_data);
1224 }
1225
1226 static int db_ctdb_traverse_read(struct db_context *db,
1227 int (*fn)(struct db_record *rec,
1228 void *private_data),
1229 void *private_data)
1230 {
1231 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
1232 struct db_ctdb_ctx);
1233 struct traverse_state state;
1234
1235 state.db = db;
1236 state.fn = fn;
1237 state.private_data = private_data;
1238
1239 if (db->persistent) {
1240 /* for persistent databases we don't need to do a ctdb traverse,
1241 we can do a faster local traverse */
1242 return tdb_traverse_read(ctx->wtdb->tdb, traverse_persistent_callback_read, &state);
1243 }
1244
1245 ctdbd_traverse(ctx->db_id, traverse_read_callback, &state);
1246 return 0;
1247 }
1248
1249 static int db_ctdb_get_seqnum(struct db_context *db)
1250 {
1251 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
1252 struct db_ctdb_ctx);
1253 return tdb_get_seqnum(ctx->wtdb->tdb);
1254 }
1255
1256 static int db_ctdb_get_flags(struct db_context *db)
1257 {
1258 struct db_ctdb_ctx *ctx = talloc_get_type_abort(db->private_data,
1259 struct db_ctdb_ctx);
1260 return tdb_get_flags(ctx->wtdb->tdb);
1261 }
1262
1263 struct db_context *db_open_ctdb(TALLOC_CTX *mem_ctx,
1264 const char *name,
1265 int hash_size, int tdb_flags,
1266 int open_flags, mode_t mode)
1267 {
1268 struct db_context *result;
1269 struct db_ctdb_ctx *db_ctdb;
1270 char *db_path;
1271 struct ctdbd_connection *conn;
1272
1273 if (!lp_clustering()) {
1274 DEBUG(10, ("Clustering disabled -- no ctdb\n"));
1275 return NULL;
1276 }
1277
1278 if (!(result = TALLOC_ZERO_P(mem_ctx, struct db_context))) {
1279 DEBUG(0, ("talloc failed\n"));
1280 TALLOC_FREE(result);
1281 return NULL;
1282 }
1283
1284 if (!(db_ctdb = TALLOC_P(result, struct db_ctdb_ctx))) {
1285 DEBUG(0, ("talloc failed\n"));
1286 TALLOC_FREE(result);
1287 return NULL;
1288 }
1289
1290 db_ctdb->transaction = NULL;
1291 db_ctdb->db = result;
1292
1293 conn = messaging_ctdbd_connection();
1294 if (conn == NULL) {
1295 DEBUG(1, ("Could not connect to ctdb\n"));
1296 TALLOC_FREE(result);
1297 return NULL;
1298 }
1299
1300 if (!NT_STATUS_IS_OK(ctdbd_db_attach(conn, name, &db_ctdb->db_id, tdb_flags))) {
1301 DEBUG(0, ("ctdbd_db_attach failed for %s\n", name));
1302 TALLOC_FREE(result);
1303 return NULL;
1304 }
1305
1306 db_path = ctdbd_dbpath(conn, db_ctdb, db_ctdb->db_id);
1307
1308 result->persistent = ((tdb_flags & TDB_CLEAR_IF_FIRST) == 0);
1309
1310 /* only pass through specific flags */
1311 tdb_flags &= TDB_SEQNUM;
1312
1313 /* honor permissions if user has specified O_CREAT */
1314 if (open_flags & O_CREAT) {
1315 chmod(db_path, mode);
1316 }
1317
1318 db_ctdb->wtdb = tdb_wrap_open(db_ctdb, db_path, hash_size, tdb_flags, O_RDWR, 0);
1319 if (db_ctdb->wtdb == NULL) {
1320 DEBUG(0, ("Could not open tdb %s: %s\n", db_path, strerror(errno)));
1321 TALLOC_FREE(result);
1322 return NULL;
1323 }
1324 talloc_free(db_path);
1325
1326 if (result->persistent) {
1327 db_ctdb->lock_ctx = g_lock_ctx_init(db_ctdb,
1328 ctdb_conn_msg_ctx(conn));
1329 if (db_ctdb->lock_ctx == NULL) {
1330 DEBUG(0, ("g_lock_ctx_init failed\n"));
1331 TALLOC_FREE(result);
1332 return NULL;
1333 }
1334 }
1335
1336 result->private_data = (void *)db_ctdb;
1337 result->fetch_locked = db_ctdb_fetch_locked;
1338 result->fetch = db_ctdb_fetch;
1339 result->traverse = db_ctdb_traverse;
1340 result->traverse_read = db_ctdb_traverse_read;
1341 result->get_seqnum = db_ctdb_get_seqnum;
1342 result->get_flags = db_ctdb_get_flags;
1343 result->transaction_start = db_ctdb_transaction_start;
1344 result->transaction_commit = db_ctdb_transaction_commit;
1345 result->transaction_cancel = db_ctdb_transaction_cancel;
1346
1347 DEBUG(3,("db_open_ctdb: opened database '%s' with dbid 0x%x\n",
1348 name, db_ctdb->db_id));
1349
1350 return result;
1351 }
1352 #endif
reg import