xref: /titanic_41/usr/src/lib/lvm/libmeta/common/meta_mn_changelog.c (revision bf85a12b7c81d0745d5a8aff65baeff50006cde9)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <stdlib.h>
28 #include <unistd.h>
29 #include <wait.h>
30 #include <sys/time.h>
31 #include <meta.h>
32 #include <metad.h>
33 #include <mdmn_changelog.h>
34 #include <syslog.h>
35 #include <umem.h>
36 
37 /*
38  * Number of log entries per set.
39  *
40  * We want at least 4 spares available at all times
41  * in case new classes are added during a live upgrade.
42  *
43  * Allocate the entries in chunks of 16
44  */
45 #define	MDMN_LOGRECS_QUANTA	16
46 #define	MDMN_LOGRECS_MINSPARES	4
47 #define	MDMN_LOGHDR_SIZE	sizeof (mdmn_changelog_record_t)
48 #define	MDMN_LOGRECSIZE	(MDMN_LOGHDR_SIZE + MD_MN_MSG_MAXDATALEN)
49 #define	MDMN_LOGRECSIZE_OD	sizeof (mdmn_changelog_record_od_t)
50 #define	MDMN_LOGRECS_TRIMUP	((MD_MN_NCLASSES % MDMN_LOGRECS_QUANTA) > \
51 				(MDMN_LOGRECS_QUANTA - MDMN_LOGRECS_MINSPARES))
52 
53 static int	mdmn_commitlog(md_set_desc *, md_error_t *);
54 static int	mdmn_log_it(set_t, md_error_t *, mdmn_changelog_record_t *lr);
55 
56 
57 /* Global variables */
58 
59 mdmn_changelog_record_t	*mdmn_changelog[MD_MAXSETS];
60 int mdmn_changelog_snarfed[MD_MAXSETS];
61 
62 /* Total number of log records */
63 int mdmn_logrecs = (MDMN_LOGRECS_QUANTA +
64 		((MD_MN_NCLASSES/MDMN_LOGRECS_QUANTA) * MDMN_LOGRECS_QUANTA));
65 
66 #ifdef DEBUG
67 void
dump_rec(char * fn_name,mdmn_changelog_record_t * lr)68 dump_rec(char *fn_name, mdmn_changelog_record_t *lr)
69 {
70 	syslog(LOG_DEBUG, "%s incore: selfid 0x%x class %d flags %d "
71 	    "msglen %d\n", fn_name, lr->lr_selfid, lr->lr_class,
72 	    lr->lr_flags, lr->lr_msglen);
73 }
74 void
dump_rec_od(char * fn_name,mdmn_changelog_record_od_t * lr)75 dump_rec_od(char *fn_name, mdmn_changelog_record_od_t *lr)
76 {
77 	syslog(LOG_DEBUG, "%s ondisk: selfid 0x%x class %d flags %d "
78 	    "msglen %d\n", fn_name, lr->lr_selfid, lr->lr_class,
79 	    lr->lr_flags, lr->lr_msglen);
80 }
81 
82 void
dump_array(char * fn_name,set_t setno)83 dump_array(char *fn_name, set_t setno)
84 {
85 	int i;
86 	char tchar[80];
87 
88 	mdmn_changelog_record_t *tlr;
89 
90 	for (i = 0; i < mdmn_logrecs; i++) {
91 		tlr = &mdmn_changelog[setno][i];
92 		(void) snprintf(tchar, sizeof (tchar), "%s class %d ",
93 		    fn_name, i);
94 		dump_rec(tchar, tlr);
95 	}
96 }
97 #endif
98 
99 /*
100  * copy_changelog: copies changelog ondisk<->incore records.
101  * The argument "direction" controls the direction to copy the
102  * the records. Incore and ondisk changlog structures must be
103  * allocated when calling this routine.
104  *
105  * The purpose of changelog is to store a message that is in progress.
106  * Therefore the changlog structure embeds the message structure.
107  * Incore and ondisk changelog structures are created to handle the
108  * incore and ondisk message formats. The incore message has a pointer
109  * to the payload. The ondisk message format has payload embedded as
110  * part of the message.
111  *
112  * Caveat Emptor: Incore and ondisk structures have the payload buffers
113  * correctly allocated.
114  */
115 
116 static void
copy_changelog(mdmn_changelog_record_t * incp,mdmn_changelog_record_od_t * odp,int direction)117 copy_changelog(mdmn_changelog_record_t *incp,
118 		mdmn_changelog_record_od_t *odp, int direction)
119 {
120 	assert(incp != NULL && odp != NULL);
121 	assert((direction == MD_MN_COPY_TO_ONDISK) ||
122 	    (direction == MD_MN_COPY_TO_INCORE));
123 
124 	if (direction == MD_MN_COPY_TO_ONDISK) {
125 		odp->lr_revision = incp->lr_revision;
126 		odp->lr_flags = incp->lr_flags;
127 		odp->lr_selfid = incp->lr_selfid;
128 		odp->lr_class = incp->lr_class;
129 		odp->lr_msglen = incp->lr_msglen;
130 		if (incp->lr_msglen)
131 			copy_msg_2(&incp->lr_msg, &odp->lr_od_msg, direction);
132 	} else {
133 		incp->lr_revision = odp->lr_revision;
134 		incp->lr_flags = odp->lr_flags;
135 		incp->lr_selfid = odp->lr_selfid;
136 		incp->lr_class = odp->lr_class;
137 		incp->lr_msglen = odp->lr_msglen;
138 		if (odp->lr_msglen)
139 			copy_msg_2(&incp->lr_msg, &odp->lr_od_msg, direction);
140 	}
141 }
142 
143 /*
144  * mdmn_allocate_changelog
145  *
146  * Changelog records are allocated on a per multi-node basis.
147  * This routine is called during MN set creation.
148  * It pre-allocates the changelog, as user records
149  * one per message class plus some spares.
150  * Once the records are allocated they are never freed until
151  * the mddb is deleted. The preallocation ensures that all nodes
152  * will have a consistent view of the mddb.
153  *
154  * Each record is large enough to hold a maximum sized message
155  * Return Values:
156  *	0 - success
157  *	-1 - fail
158  */
159 int
mdmn_allocate_changelog(mdsetname_t * sp,md_error_t * ep)160 mdmn_allocate_changelog(mdsetname_t *sp, md_error_t *ep)
161 {
162 	mddb_userreq_t		req;
163 	md_set_desc		*sd;
164 	mdmn_changelog_record_t	*tlr;
165 	int			i;
166 	set_t			setno;
167 
168 	/* Get a pointer to the incore md_set_desc for this MN set */
169 	if ((sd = metaget_setdesc(sp, ep)) == NULL)
170 		return (-1);
171 	setno = sd->sd_setno;
172 	/*
173 	 * Round up the number of changelog records
174 	 * to the next value of MDMN_LOGRECS_QUANTA
175 	 *
176 	 * In all cases, make sure we have at least
177 	 * four more entries than the number of classes
178 	 * in order to provide space for live upgrades that
179 	 * might add classes.
180 	 */
181 
182 	mdmn_logrecs += (MDMN_LOGRECS_TRIMUP) ? MDMN_LOGRECS_QUANTA : 0;
183 
184 	mdmn_changelog[setno] = Zalloc(MDMN_LOGHDR_SIZE * mdmn_logrecs);
185 
186 	for (i = 0; i < mdmn_logrecs; i++) {
187 		(void) memset(&req, 0, sizeof (req));
188 		METAD_SETUP_LR(MD_DB_CREATE, setno,  0);
189 		/* grab a record big enough for max message size */
190 		req.ur_size = MDMN_LOGRECSIZE_OD;
191 
192 		if (metaioctl(MD_MN_DB_USERREQ, &req, &req.ur_mde, NULL) != 0) {
193 			(void) mdstealerror(ep, &req.ur_mde);
194 #ifdef DEBUG
195 			syslog(LOG_DEBUG, "allocate_log: %s\n",
196 			    mde_sperror(ep, ""));
197 #endif
198 			Free(mdmn_changelog[setno]);
199 			return (-1);
200 		}
201 
202 		tlr = &mdmn_changelog[setno][i];
203 		tlr->lr_selfid = req.ur_recid;
204 		tlr->lr_revision = MD_MN_CHANGELOG_RECORD_REVISION;
205 		tlr->lr_class = i;
206 	}
207 
208 	/* commit class, and selfid */
209 	(void) mdmn_commitlog(sd, ep);
210 	Free(mdmn_changelog[setno]);
211 	return (0);
212 }
213 
214 /*
215  * mdmn_reset_changelog
216  *
217  * Called during reconfig step 2.
218  * The only time the changelog is reset is when all nodes in a cluster
219  * are starting up. In this case changelog must be ignored, therefore
220  * it is reset.
221  *
222  * The function frees the incore data structures and zeros out the
223  * records. The ondisk records are never freed.
224  *
225  * Return Values:
226  *	0 - success
227  *	-1 - fail
228  */
229 int
mdmn_reset_changelog(mdsetname_t * sp,md_error_t * ep,int flag)230 mdmn_reset_changelog(mdsetname_t *sp, md_error_t *ep, int flag)
231 {
232 	md_set_desc		*sd;
233 	mdmn_changelog_record_t	*lr;
234 	set_t			setno;
235 	int			lrc;
236 
237 	/* Get a pointer to the incore md_set_desc this MN set */
238 	if ((sd = metaget_setdesc(sp, ep)) == NULL)
239 		return (-1);
240 
241 	setno = sd->sd_setno;
242 
243 	if (mdmn_snarf_changelog(setno, ep) == 0) {
244 		return (0);
245 	}
246 
247 	if (flag & MDMN_CLF_RESETLOG) {
248 		for (lrc = 0; lrc < mdmn_logrecs; lrc++) {
249 			lr = &mdmn_changelog[setno][lrc];
250 			Free(lr->lr_msg.msg_event_data);
251 			(void) memset(&lr->lr_msg, 0, sizeof (md_mn_msg_t));
252 			lr->lr_msglen = 0;
253 			lr->lr_flags = 0;
254 		}
255 		(void) mdmn_commitlog(sd, ep);
256 #ifdef DEBUG
257 		syslog(LOG_DEBUG, "reset_changelog: Log reset\n");
258 #endif
259 	}
260 	/* now zap the array */
261 	if (flag & MDMN_CLF_RESETCACHE) {
262 #ifdef DEBUG
263 		syslog(LOG_DEBUG, "reset_changelog: cache reset\n");
264 #endif
265 		Free(&mdmn_changelog[setno]);
266 		mdmn_changelog[setno] = NULL;
267 		mdmn_changelog_snarfed[setno] = 0;
268 	}
269 	return (0);
270 }
271 
272 /*
273  * Log a given message in the changelog.
274  * This function is only executed by the master node
275  * Return Values:
276  *	MDMNE_NULL:
277  *	    success, the log slot is free
278  *
279  *	MDMNE_ACK:
280  *	    success,
281  *	    the log slot is occupied with the same msg from a previous try.
282  *
283  *	MDMNE_CLASS_BUSY:
284  *	    This means the appropriate slot is occupied with a different
285  *	    message. In that case the stored message needs being replayed,
286  *	    while the current message will be rejected with MDMNE_CLASS_BUSY
287  *	    to the initiator.
288  *
289  *	MDMNE_LOG_FAIL:
290  *	    Bad things happend, cannot continue.
291  */
292 int
mdmn_log_msg(md_mn_msg_t * msg)293 mdmn_log_msg(md_mn_msg_t *msg)
294 {
295 	set_t		setno;
296 	md_mn_msgclass_t	class;
297 	mdmn_changelog_record_t	*lr;
298 	md_error_t		err = mdnullerror;
299 	md_error_t		*ep = &err;
300 	int			retval = 0;
301 
302 	setno = msg->msg_setno;
303 	class = mdmn_get_message_class(msg->msg_type);
304 
305 	/* if not snarfed, snarf it */
306 	if (mdmn_snarf_changelog(setno, ep) <= 0) {
307 		syslog(LOG_DAEMON | LOG_ERR, dgettext(TEXT_DOMAIN,
308 		    "log_msg: No records snarfed\n"));
309 		return (-1);
310 	}
311 
312 
313 	/* log entry for the class */
314 	lr = &mdmn_changelog[setno][class];
315 
316 	/* Check if the class is occupied */
317 	if (lr->lr_flags & MD_MN_LR_INUSE) {
318 		if (!MSGID_CMP(&(msg->msg_msgid), &(lr->lr_msg.msg_msgid))) {
319 			syslog(LOG_DAEMON | LOG_DEBUG, dgettext(TEXT_DOMAIN,
320 			    "log_msg: id mismatch:\n"
321 			    " stored    : ID = (%d, 0x%llx-%d)"
322 			    " setno %d class %d type %d\n"
323 			    " msg to log: ID = (%d, 0x%llx-%d)"
324 			    " setno %d class %d type %d.\n"),
325 			    MSGID_ELEMS(lr->lr_msg.msg_msgid), lr->lr_setno,
326 			    lr->lr_class, lr->lr_msgtype,
327 			    MSGID_ELEMS(msg->msg_msgid), msg->msg_setno, class,
328 			    msg->msg_type);
329 			return (MDMNE_CLASS_BUSY);
330 		} else {
331 			syslog(LOG_DAEMON | LOG_DEBUG, dgettext(TEXT_DOMAIN,
332 			    "log_msg: msgid already logged:\n ID = "
333 			    " (%d, 0x%llx-%d) setno %d class %d type %d\n"),
334 			    MSGID_ELEMS(lr->lr_msg.msg_msgid), lr->lr_setno,
335 			    lr->lr_class, lr->lr_msgtype);
336 			return (MDMNE_ACK);
337 		}
338 	}
339 
340 	lr->lr_flags |= MD_MN_LR_INUSE;
341 	lr->lr_msglen = MD_MN_MSG_LEN(msg);
342 	assert(lr->lr_msg.msg_event_data == NULL);
343 	if (msg->msg_event_size)
344 		lr->lr_msg.msg_event_data = Zalloc(msg->msg_event_size);
345 	(void) copy_msg(msg, &(lr->lr_msg));
346 	retval = mdmn_log_it(setno, ep, lr);
347 	if (retval != 0) {
348 		syslog(LOG_DAEMON | LOG_ERR, dgettext(TEXT_DOMAIN,
349 		    "mdmn_log_msg - failure committing logged msg to disk\n"));
350 		return (MDMNE_LOG_FAIL);
351 	}
352 
353 	return (MDMNE_NULL); /* this is good */
354 }
355 
356 /*
357  * mdmn_unlog_msg(md_mn_msg_t *)
358  *
359  * Clear the log entry holding the indicated message.
360  * Only the set master can do this.
361  *
362  * Return Values:
363  *	0 - success
364  *	-1 - fail
365  */
366 int
mdmn_unlog_msg(md_mn_msg_t * msg)367 mdmn_unlog_msg(md_mn_msg_t *msg)
368 {
369 	set_t			setno;
370 	md_mn_msgclass_t	class;
371 	md_error_t		err = mdnullerror;
372 	md_error_t		*ep = &err;
373 	int			retval = 0;
374 	mdmn_changelog_record_t	*lr = NULL;
375 
376 	setno = msg->msg_setno;
377 	class = mdmn_get_message_class(msg->msg_type);
378 
379 	/* Find the log entry holding the indicated message */
380 	if (mdmn_snarf_changelog(setno, ep) == 0)
381 		return (-1);
382 
383 	lr = &mdmn_changelog[setno][class];
384 
385 	/* assert the message is still logged */
386 	assert(lr != NULL);
387 	if (!MSGID_CMP(&(msg->msg_msgid), &(lr->lr_msg.msg_msgid))) {
388 		syslog(LOG_ERR, dgettext(TEXT_DOMAIN,
389 		    "unlog_msg: msgid mismatch\n"
390 		    "\t\tstored: ID = (%d, 0x%llx-%d) setno %d "
391 		    "class %d type %d\n"
392 		    "\t\tattempting to unlog:\n"
393 		    "\t\tID = (%d, 0x%llx-%d) setno %d class %d type %d.\n"),
394 		    MSGID_ELEMS(lr->lr_msg.msg_msgid), lr->lr_setno,
395 		    lr->lr_class, lr->lr_msgtype, MSGID_ELEMS(msg->msg_msgid),
396 		    msg->msg_setno, class, msg->msg_type);
397 		return (-1);
398 	}
399 	lr->lr_msglen = 0;
400 	lr->lr_flags &= ~(MD_MN_LR_INUSE);
401 	if (lr->lr_msg.msg_event_data) {
402 		Free(lr->lr_msg.msg_event_data);
403 		lr->lr_msg.msg_event_data = NULL;
404 	}
405 	/* commit the updated log record to disk */
406 	retval = mdmn_log_it(setno, ep, lr);
407 #ifdef DEBUG
408 	dump_rec("mdmn_unlog_msg: ", lr);
409 #endif
410 	return (retval);
411 }
412 
413 
414 /*
415  * mdmn_get_changelogrec(set_t , md_mn_msgclass_t)
416  * Returns a pointer to incore changelog record.
417  *
418  * Return Values:
419  *	non-NULL - success
420  *	NULL - fail
421  */
422 mdmn_changelog_record_t *
mdmn_get_changelogrec(set_t setno,md_mn_msgclass_t class)423 mdmn_get_changelogrec(set_t setno, md_mn_msgclass_t class)
424 {
425 	md_error_t	err = mdnullerror;
426 
427 	if (mdmn_snarf_changelog(setno, &err) == 0)
428 		return (NULL);
429 	assert(mdmn_changelog[setno] != NULL);
430 
431 	return (&mdmn_changelog[setno][class]);
432 }
433 
434 /*
435  * mdmn_commitlog(md_set_desc *, md_error_t *)
436  *
437  * Commit the set record and all of the changelog entry records to disk.
438  * Don't bother with other stuff hanging off the set record
439  * (e.g. drive records) since none of that is changing.
440  * Called only at changelog pre-allocation time or when flushing a log.
441  *
442  * Return Values:
443  *	0 - success
444  *	errno - fail
445  */
446 
447 static int
mdmn_commitlog(md_set_desc * sd,md_error_t * ep)448 mdmn_commitlog(md_set_desc *sd, md_error_t *ep)
449 {
450 	int			lrc;
451 	int			*recs;
452 	uint_t			size;
453 	mdmn_changelog_record_t	*lr;
454 	mdmn_changelog_record_od_t clodrec; /* changelog ondisk record */
455 	mddb_userreq_t		req;
456 	int			retval = 0;
457 	set_t			setno;
458 
459 	/* Check for master and bounce non-master requests */
460 	if (!(MD_MNSET_DESC(sd)) || !sd->sd_mn_am_i_master) {
461 		if (!(MD_MNSET_DESC(sd))) {
462 			syslog(LOG_DAEMON | LOG_ERR, dgettext(TEXT_DOMAIN,
463 			    "mdmn_commitlog - Not MN Set\n"));
464 		} else {
465 			syslog(LOG_DAEMON | LOG_ERR, dgettext(TEXT_DOMAIN,
466 			    "mdmn_commit_log - Not Master\n"));
467 		}
468 		return (-1);
469 	}
470 	(void) memset(&req, 0, sizeof (req));
471 	/* create the records to commit the info to the mddb */
472 
473 	size = (mdmn_logrecs + 1) * sizeof (int);
474 	recs = Zalloc(size);
475 	/* Initialize the log entry records for update */
476 	setno = sd->sd_setno;
477 
478 	for (lrc = 0; lrc < mdmn_logrecs; lrc++) {
479 		lr = &mdmn_changelog[setno][lrc];
480 		recs[lrc] = lr->lr_selfid;
481 		copy_changelog(lr, &clodrec, MD_MN_COPY_TO_ONDISK);
482 		METAD_SETUP_LR(MD_DB_SETDATA, setno, lr->lr_selfid);
483 		req.ur_size  = MDMN_LOGRECSIZE_OD;
484 		req.ur_data = (uintptr_t)&clodrec;
485 		if ((retval = metaioctl(MD_MN_DB_USERREQ, &req, &req.ur_mde,
486 		    NULL)) != 0) {
487 			(void) mdstealerror(ep, &req.ur_mde);
488 #ifdef DEBUG
489 			syslog(LOG_DAEMON|LOG_DEBUG,
490 			    "mdmn_commitlog - metaioctl SETDATA failure\n%s",
491 			    mde_sperror(ep, ""));
492 #endif
493 			break;
494 		}
495 	}
496 
497 	if (retval == 0) {
498 		/* set last rec to be 0 to indicate completion */
499 		recs[lrc] = 0;
500 		/* Commit to mddb  on disk */
501 		METAD_SETUP_LR(MD_DB_COMMIT_MANY, setno,
502 		    mdmn_changelog[setno][0].lr_selfid);
503 		req.ur_size = size;
504 		req.ur_data = (uintptr_t)recs;
505 		if ((retval = metaioctl(MD_MN_DB_USERREQ, &req,
506 		    &req.ur_mde, NULL)) != 0) {
507 			(void) mdstealerror(ep, &req.ur_mde);
508 #ifdef DEBUG
509 			syslog(LOG_DAEMON|LOG_DEBUG,
510 			    "mdmn_commitlog - metaioctl COMMIT_MANY"
511 			    "Failure\n%s",  mde_sperror(ep, ""));
512 #endif
513 		}
514 	}
515 
516 	Free(recs);
517 	return (retval);
518 }
519 
520 /*
521  * mdmn_log_it(set_t, md_error_t *, mdmn_changelog_record_t *)
522  *
523  * Commit the changed log record to disk.
524  *
525  * Return Values:
526  *	0 - success
527  *	-1 - fail
528  */
529 static int
mdmn_log_it(set_t set,md_error_t * ep,mdmn_changelog_record_t * lr)530 mdmn_log_it(set_t set, md_error_t *ep, mdmn_changelog_record_t *lr)
531 {
532 	int			*recs;
533 	uint_t			size;
534 	mddb_userreq_t		req;
535 	mdmn_changelog_record_od_t	clodrec;
536 
537 	(void) memset(&req, 0, sizeof (req));
538 
539 	/* Initialize the log entry record for update */
540 
541 	copy_changelog(lr, &clodrec, MD_MN_COPY_TO_ONDISK);
542 	METAD_SETUP_LR(MD_DB_SETDATA, set, lr->lr_selfid);
543 	req.ur_size = MDMN_LOGRECSIZE_OD;
544 	req.ur_data = (uintptr_t)&clodrec;
545 	if (metaioctl(MD_MN_DB_USERREQ, &req, &req.ur_mde, NULL) != 0) {
546 		(void) mdstealerror(ep, &req.ur_mde);
547 #ifdef DEBUG
548 		syslog(LOG_DEBUG, "mdmn_log_it: DB_SETDATA  failed\n"
549 		    "set %d selfid %d, size %d\n%s", set, lr->lr_selfid,
550 		    req.ur_size, mde_sperror(ep, ""));
551 #endif
552 		return (-1);
553 	}
554 	/* Set up the recid to be updated */
555 	size = 2 * sizeof (int); /* the changed record, plus null terminator */
556 	recs = Zalloc(size);
557 	recs[0] = lr->lr_selfid;
558 	recs[1] = 0;
559 	/* Commit to mddb  on disk */
560 	METAD_SETUP_LR(MD_DB_COMMIT_ONE, set, lr->lr_selfid);
561 	req.ur_size = size;
562 	req.ur_data = (uintptr_t)recs;
563 	if (metaioctl(MD_MN_DB_USERREQ, &req, &req.ur_mde, NULL) != 0) {
564 		(void) mdstealerror(ep, &req.ur_mde);
565 #ifdef DEBUG
566 		syslog(LOG_DEBUG, "mdmn_log_it: DB_COMMIT_ONE  failed\n"
567 		    "set %d selfid %d, size %d\n%s", set, lr->lr_selfid,
568 		    req.ur_size, mde_sperror(ep, ""));
569 #endif
570 		Free(recs);
571 		return (-1);
572 	}
573 	Free(recs);
574 	return (0);
575 }
576 
577 /*
578  * mdmn_snarf_changelog(set_t, md_error_t *)
579  *
580  * snarf in the changelog entries and allocate incore structures
581  * if required.
582  * mdmn_changelog_snarfed array if set to MDMN_CLF_SNARFED, then
583  * then the records are already snarfed.
584  *
585  * Called from set_snarf(), mdmn_log_msg(), and mdmn_unlog_msg()
586  * Return Values:
587  *	non-zero - success
588  *	0 - fail
589  */
590 int
mdmn_snarf_changelog(set_t set,md_error_t * ep)591 mdmn_snarf_changelog(set_t set, md_error_t *ep)
592 {
593 	mdmn_changelog_record_t	 *tlr;
594 	mdmn_changelog_record_od_t	 *lr;
595 	mddb_recid_t		id;
596 	md_mn_msgclass_t	class;
597 
598 
599 	if (set == MD_LOCAL_SET)
600 		return (0);
601 
602 	id = 0;
603 
604 	if (mdmn_changelog_snarfed[set] & MDMN_CLF_SNARFED) {
605 		assert(mdmn_changelog[set] != NULL);
606 		return (mdmn_logrecs);
607 	}
608 
609 	lr = (mdmn_changelog_record_od_t *)get_ur_rec(set, MD_UR_GET_NEXT,
610 	    MDDB_UR_LR, &id, ep);
611 	if (lr == NULL)
612 		return (0);
613 
614 	/* only allocate if Log records exist */
615 
616 	if (mdmn_changelog[set] == NULL) {
617 		/* Allocate incore state for the log */
618 		mdmn_changelog[set] = Zalloc(MDMN_LOGHDR_SIZE *
619 		    mdmn_logrecs);
620 	}
621 
622 	do {
623 		class = lr->lr_class;
624 		tlr = &mdmn_changelog[set][class];
625 		copy_changelog(tlr, lr, MD_MN_COPY_TO_INCORE);
626 		Free(lr);
627 		lr = (mdmn_changelog_record_od_t *)get_ur_rec(set,
628 		    MD_UR_GET_NEXT, MDDB_UR_LR, &id, ep);
629 	} while (lr != NULL);
630 
631 	/* Since log records counts are fixed return that value */
632 	mdmn_changelog_snarfed[set] |= MDMN_CLF_SNARFED;
633 	return (mdmn_logrecs);
634 }
635