2 * Copyright 2000, International Business Machines Corporation and others.
5 * This software has been released under the terms of the IBM Public
6 * License. For details, see the LICENSE file in the top-level source
7 * directory or online at http://www.openafs.org/dl/license10.html
10 #include <afsconfig.h>
11 #include <afs/param.h>
16 #include <sys/types.h>
23 #include <netinet/in.h>
32 #include <afs/afsutil.h>
34 #define UBIK_INTERNALS
38 /* This module is responsible for determining when the system has
39 * recovered to the point that it can handle new transactions. It
40 * replays logs, polls to determine the current dbase after a crash,
41 * and distributes the new database to the others.
44 /* The sync site associates a version number with each database. It
45 * broadcasts the version associated with its current dbase in every
46 * one of its beacon messages. When the sync site send a dbase to a
47 * server, it also sends the db's version. A non-sync site server can
48 * tell if it has the right dbase version by simply comparing the
49 * version from the beacon message (uvote_dbVersion) with the version
50 * associated with the database (ubik_dbase->version). The sync site
51 * itself simply has one counter to keep track of all of this (again
52 * ubik_dbase->version).
55 /* sync site: routine called when the sync site loses its quorum; this
56 * procedure is called "up" from the beacon package. It resyncs the
57 * dbase and nudges the recovery daemon to try to propagate out the
58 * changes. It also resets the recovery daemon's state, since
59 * recovery must potentially find a new dbase to propagate out. This
60 * routine should not do anything with variables used by non-sync site
64 /* if this flag is set, then ubik will use only the primary address
65 ** ( the address specified in the CellServDB) to contact other
66 ** ubik servers. Ubik recovery will not try opening connections
67 ** to the alternate interface addresses.
69 int ubikPrimaryAddrOnly;
72 urecovery_ResetState(void)
75 LWP_NoYieldSignal(&urecovery_state);
79 /* sync site: routine called when a non-sync site server goes down; restarts recovery
80 * process to send missing server the new db when it comes back up.
81 * This routine should not do anything with variables used by non-sync site servers.
84 urecovery_LostServer(void)
86 LWP_NoYieldSignal(&urecovery_state);
90 /* return true iff we have a current database (called by both sync
91 * sites and non-sync sites) How do we determine this? If we're the
92 * sync site, we wait until recovery has finished fetching and
93 * re-labelling its dbase (it may still be trying to propagate it out
94 * to everyone else; that's THEIR problem). If we're not the sync
95 * site, then we must have a dbase labelled with the right version,
96 * and we must have a currently-good sync site.
99 urecovery_AllBetter(register struct ubik_dbase *adbase, int areadAny)
101 register afs_int32 rcode;
103 ubik_dprint("allbetter checking\n");
108 if (ubik_dbase->version.epoch > 1)
109 rcode = 1; /* Happy with any good version of database */
112 /* Check if we're sync site and we've got the right data */
113 else if (ubeacon_AmSyncSite() && (urecovery_state & UBIK_RECHAVEDB)) {
117 /* next, check if we're aux site, and we've ever been sent the
118 * right data (note that if a dbase update fails, we won't think
119 * that the sync site is still the sync site, 'cause it won't talk
120 * to us until a timeout period has gone by. When we recover, we
121 * leave this clear until we get a new dbase */
122 else if ((uvote_GetSyncSite() && (vcmp(ubik_dbVersion, ubik_dbase->version) == 0))) { /* && order is important */
126 ubik_dprint("allbetter: returning %d\n", rcode);
130 /* abort all transactions on this database */
132 urecovery_AbortAll(struct ubik_dbase *adbase)
134 register struct ubik_trans *tt;
135 for (tt = adbase->activeTrans; tt; tt = tt->next) {
141 /* this routine aborts the current remote transaction, if any, if the tid is wrong */
143 urecovery_CheckTid(register struct ubik_tid *atid)
145 if (ubik_currentTrans) {
146 /* there is remote write trans, see if we match, see if this
147 * is a new transaction */
148 if (atid->epoch != ubik_currentTrans->tid.epoch
149 || atid->counter > ubik_currentTrans->tid.counter) {
150 /* don't match, abort it */
151 /* If the thread is not waiting for lock - ok to end it */
152 #if !defined(UBIK_PAUSE)
153 if (ubik_currentTrans->locktype != LOCKWAIT) {
154 #endif /* UBIK_PAUSE */
155 udisk_end(ubik_currentTrans);
156 #if !defined(UBIK_PAUSE)
158 #endif /* UBIK_PAUSE */
159 ubik_currentTrans = (struct ubik_trans *)0;
165 /* log format is defined here, and implicitly in disk.c
167 * 4 byte opcode, followed by parameters, each 4 bytes long. All integers
168 * are in logged in network standard byte order, in case we want to move logs
169 * from machine-to-machine someday.
171 * Begin transaction: opcode
172 * Commit transaction: opcode, version (8 bytes)
173 * Truncate file: opcode, file number, length
174 * Abort transaction: opcode
175 * Write data: opcode, file, position, length, <length> data bytes
177 * A very simple routine, it just replays the log. Note that this is a new-value only log, which
178 * implies that no uncommitted data is written to the dbase: one writes data to the log, including
179 * the commit record, then we allow data to be written through to the dbase. In our particular
180 * implementation, once a transaction is done, we write out the pages to the database, so that
181 * our buffer package doesn't have to know about stable and uncommitted data in the memory buffers:
182 * any changed data while there is an uncommitted write transaction can be zapped during an
183 * abort and the remaining dbase on the disk is exactly the right dbase, without having to read
189 ReplayLog(register struct ubik_dbase *adbase)
192 register afs_int32 code, tpos;
194 afs_int32 len, thisSize, tfile, filePos;
196 afs_int32 syncFile = -1;
197 afs_int32 data[1024];
199 /* read the lock twice, once to see whether we have a transaction to deal
200 * with that committed, (theoretically, we should support more than one
201 * trans in the log at once, but not yet), and once replaying the
205 /* for now, assume that all ops in log pertain to one transaction; see if there's a commit */
208 (*adbase->read) (adbase, LOGFILE, (char *)&opcode, tpos,
210 if (code != sizeof(afs_int32))
212 if (opcode == LOGNEW) {
213 /* handle begin trans */
214 tpos += sizeof(afs_int32);
215 } else if (opcode == LOGABORT)
217 else if (opcode == LOGEND) {
220 } else if (opcode == LOGTRUNCATE) {
223 (*adbase->read) (adbase, LOGFILE, (char *)buffer, tpos,
224 2 * sizeof(afs_int32));
225 if (code != 2 * sizeof(afs_int32))
226 break; /* premature eof or io error */
227 tpos += 2 * sizeof(afs_int32);
228 } else if (opcode == LOGDATA) {
231 (*adbase->read) (adbase, LOGFILE, (char *)buffer, tpos,
232 3 * sizeof(afs_int32));
233 if (code != 3 * sizeof(afs_int32))
235 /* otherwise, skip over the data bytes, too */
236 tpos += buffer[2] + 3 * sizeof(afs_int32);
238 ubik_dprint("corrupt log opcode (%d) at position %d\n", opcode,
240 break; /* corrupt log! */
244 /* actually do the replay; log should go all the way through the commit record, since
245 * we just read it above. */
251 (*adbase->read) (adbase, LOGFILE, (char *)&opcode, tpos,
253 if (code != sizeof(afs_int32))
255 if (opcode == LOGNEW) {
256 /* handle begin trans */
257 tpos += sizeof(afs_int32);
258 } else if (opcode == LOGABORT)
259 panic("log abort\n");
260 else if (opcode == LOGEND) {
263 (*adbase->read) (adbase, LOGFILE, (char *)buffer, tpos,
264 2 * sizeof(afs_int32));
265 if (code != 2 * sizeof(afs_int32))
267 code = (*adbase->setlabel) (adbase, 0, (ubik_version *)buffer);
271 break; /* all done now */
272 } else if (opcode == LOGTRUNCATE) {
275 (*adbase->read) (adbase, LOGFILE, (char *)buffer, tpos,
276 2 * sizeof(afs_int32));
277 if (code != 2 * sizeof(afs_int32))
278 break; /* premature eof or io error */
279 tpos += 2 * sizeof(afs_int32);
281 (*adbase->truncate) (adbase, ntohl(buffer[0]),
285 } else if (opcode == LOGDATA) {
288 (*adbase->read) (adbase, LOGFILE, (char *)buffer, tpos,
289 3 * sizeof(afs_int32));
290 if (code != 3 * sizeof(afs_int32))
292 tpos += 3 * sizeof(afs_int32);
293 /* otherwise, skip over the data bytes, too */
294 len = ntohl(buffer[2]); /* total number of bytes to copy */
295 filePos = ntohl(buffer[1]);
296 tfile = ntohl(buffer[0]);
297 /* try to minimize file syncs */
298 if (syncFile != tfile) {
300 code = (*adbase->sync) (adbase, syncFile);
308 thisSize = (len > sizeof(data) ? sizeof(data) : len);
309 /* copy sizeof(data) buffer bytes at a time */
311 (*adbase->read) (adbase, LOGFILE, (char *)data, tpos,
313 if (code != thisSize)
316 (*adbase->write) (adbase, tfile, (char *)data, filePos,
318 if (code != thisSize)
325 ubik_dprint("corrupt log opcode (%d) at position %d\n",
327 break; /* corrupt log! */
332 code = (*adbase->sync) (adbase, syncFile);
336 ubik_dprint("Log read error on pass 2\n");
341 /* now truncate the log, we're done with it */
342 code = (*adbase->truncate) (adbase, LOGFILE, 0);
346 /* Called at initialization to figure out version of the dbase we really have.
347 * This routine is called after replaying the log; it reads the restored labels.
350 InitializeDB(register struct ubik_dbase *adbase)
352 register afs_int32 code;
354 code = (*adbase->getlabel) (adbase, 0, &adbase->version);
356 /* try setting the label to a new value */
357 adbase->version.epoch = 1; /* value for newly-initialized db */
358 adbase->version.counter = 1;
359 code = (*adbase->setlabel) (adbase, 0, &adbase->version);
361 /* failed, try to set it back */
362 adbase->version.epoch = 0;
363 adbase->version.counter = 0;
364 (*adbase->setlabel) (adbase, 0, &adbase->version);
366 LWP_NoYieldSignal(&adbase->version);
371 /* initialize the local dbase
372 * We replay the logs and then read the resulting file to figure out what version we've really got.
375 urecovery_Initialize(register struct ubik_dbase *adbase)
377 register afs_int32 code;
379 code = ReplayLog(adbase);
382 code = InitializeDB(adbase);
386 /* Main interaction loop for the recovery manager
387 * The recovery light-weight process only runs when you're the
388 * synchronization site. It performs the following tasks, if and only
389 * if the prerequisite tasks have been performed successfully (it
390 * keeps track of which ones have been performed in its bit map,
393 * First, it is responsible for probing that all servers are up. This
394 * is the only operation that must be performed even if this is not
395 * yet the sync site, since otherwise this site may not notice that
396 * enough other machines are running to even elect this guy to be the
399 * After that, the recovery process does nothing until the beacon and
400 * voting modules manage to get this site elected sync site.
402 * After becoming sync site, recovery first attempts to find the best
403 * database available in the network (it must do this in order to
404 * ensure finding the latest committed data). After finding the right
405 * database, it must fetch this dbase to the sync site.
407 * After fetching the dbase, it relabels it with a new version number,
408 * to ensure that everyone recognizes this dbase as the most recent
411 * One the dbase has been relabelled, this machine can start handling
412 * requests. However, the recovery module still has one more task:
413 * propagating the dbase out to everyone who is up in the network.
416 urecovery_Interact(void)
418 afs_int32 code, tcode;
419 struct ubik_server *bestServer = NULL;
420 struct ubik_server *ts;
421 int dbok, doingRPC, now;
422 afs_int32 lastProbeTime, lastDBVCheck;
423 /* if we're the sync site, the best db version we've found yet */
424 static struct ubik_version bestDBVersion;
425 struct ubik_version tversion;
427 int length, tlen, offset, file, nbytes;
428 struct rx_call *rxcall;
430 struct ubik_stat ubikstat;
431 struct in_addr inAddr;
432 #ifndef OLD_URECOVERY
437 /* otherwise, begin interaction */
442 /* Run through this loop every 4 seconds */
445 IOMGR_Select(0, 0, 0, 0, &tv);
447 ubik_dprint("recovery running in state %x\n", urecovery_state);
449 /* Every 30 seconds, check all the down servers and mark them
450 * as up if they respond. When a server comes up or found to
451 * not be current, then re-find the the best database and
454 if ((now = FT_ApproxTime()) > 30 + lastProbeTime) {
455 for (ts = ubik_servers, doingRPC = 0; ts; ts = ts->next) {
461 urecovery_state &= ~UBIK_RECFOUNDDB;
463 } else if (!ts->currentDB) {
464 urecovery_state &= ~UBIK_RECFOUNDDB;
468 now = FT_ApproxTime();
472 /* Mark whether we are the sync site */
473 if (!ubeacon_AmSyncSite()) {
474 urecovery_state &= ~UBIK_RECSYNCSITE;
475 continue; /* nothing to do */
477 urecovery_state |= UBIK_RECSYNCSITE;
479 /* If a server has just come up or if we have not found the
480 * most current database, then go find the most current db.
482 if (!(urecovery_state & UBIK_RECFOUNDDB)) {
483 bestServer = (struct ubik_server *)0;
484 bestDBVersion.epoch = 0;
485 bestDBVersion.counter = 0;
486 for (ts = ubik_servers; ts; ts = ts->next) {
488 continue; /* don't bother with these guys */
491 code = DISK_GetVersion(ts->disk_rxcid, &ts->version);
493 /* perhaps this is the best version */
494 if (vcmp(ts->version, bestDBVersion) > 0) {
495 /* new best version */
496 bestDBVersion = ts->version;
501 /* take into consideration our version. Remember if we,
502 * the sync site, have the best version. Also note that
503 * we may need to send the best version out.
505 if (vcmp(ubik_dbase->version, bestDBVersion) >= 0) {
506 bestDBVersion = ubik_dbase->version;
507 bestServer = (struct ubik_server *)0;
508 urecovery_state |= UBIK_RECHAVEDB;
510 /* Clear the flag only when we know we have to retrieve
511 * the db. Because urecovery_AllBetter() looks at it.
513 urecovery_state &= ~UBIK_RECHAVEDB;
515 lastDBVCheck = FT_ApproxTime();
516 urecovery_state |= UBIK_RECFOUNDDB;
517 urecovery_state &= ~UBIK_RECSENTDB;
519 #if defined(UBIK_PAUSE)
520 /* it's not possible for UBIK_RECFOUNDDB not to be set here.
521 * However, we might have lost UBIK_RECSYNCSITE, and that
524 if (!(urecovery_state & UBIK_RECSYNCSITE))
525 continue; /* lost sync */
527 if (!(urecovery_state & UBIK_RECFOUNDDB))
528 continue; /* not ready */
529 #endif /* UBIK_PAUSE */
531 /* If we, the sync site, do not have the best db version, then
532 * go and get it from the server that does.
534 if ((urecovery_state & UBIK_RECHAVEDB) || !bestServer) {
535 urecovery_state |= UBIK_RECHAVEDB;
537 /* we don't have the best version; we should fetch it. */
539 urecovery_AbortAll(ubik_dbase);
541 /* Rx code to do the Bulk fetch */
544 rxcall = rx_NewCall(bestServer->disk_rxcid);
546 ubik_print("Ubik: Synchronize database with server %s\n",
547 afs_inet_ntoa(bestServer->addr[0]));
549 code = StartDISK_GetFile(rxcall, file);
551 ubik_dprint("StartDiskGetFile failed=%d\n", code);
554 nbytes = rx_Read(rxcall, (char *)&length, sizeof(afs_int32));
555 length = ntohl(length);
556 if (nbytes != sizeof(afs_int32)) {
557 ubik_dprint("Rx-read length error=%d\n", code = BULK_ERROR);
563 /* Truncate the file first */
564 code = (*ubik_dbase->truncate) (ubik_dbase, file, 0);
566 ubik_dprint("truncate io error=%d\n", code);
570 /* give invalid label during file transit */
572 tversion.counter = 0;
573 code = (*ubik_dbase->setlabel) (ubik_dbase, file, &tversion);
575 ubik_dprint("setlabel io error=%d\n", code);
580 afs_snprintf(pbuffer, sizeof(pbuffer), "%s.DB0.TMP", ubik_dbase->pathName);
581 fd = open(pbuffer, O_CREAT | O_RDWR | O_TRUNC, 0600);
586 code = lseek(fd, HDRSIZE, 0);
587 if (code != HDRSIZE) {
594 tlen = (length > sizeof(tbuffer) ? sizeof(tbuffer) : length);
595 nbytes = rx_Read(rxcall, tbuffer, tlen);
596 if (nbytes != tlen) {
597 ubik_dprint("Rx-read bulk error=%d\n", code = BULK_ERROR);
604 (*ubik_dbase->write) (ubik_dbase, file, tbuffer, offset,
607 nbytes = write(fd, tbuffer, tlen);
609 if (nbytes != tlen) {
617 #ifndef OLD_URECOVERY
622 code = EndDISK_GetFile(rxcall, &tversion);
624 tcode = rx_EndCall(rxcall, code);
628 /* we got a new file, set up its header */
629 urecovery_state |= UBIK_RECHAVEDB;
630 memcpy(&ubik_dbase->version, &tversion,
631 sizeof(struct ubik_version));
633 (*ubik_dbase->sync) (ubik_dbase, 0); /* get data out first */
635 afs_snprintf(tbuffer, sizeof(tbuffer), "%s.DB0", ubik_dbase->pathName);
637 afs_snprintf(pbuffer, sizeof(pbuffer), "%s.DB0.OLD", ubik_dbase->pathName);
638 code = unlink(pbuffer);
640 code = rename(tbuffer, pbuffer);
641 afs_snprintf(pbuffer, sizeof(pbuffer), "%s.DB0.TMP", ubik_dbase->pathName);
644 code = rename(pbuffer, tbuffer);
647 /* after data is good, sync disk with correct label */
649 (*ubik_dbase->setlabel) (ubik_dbase, 0,
650 &ubik_dbase->version);
651 #ifndef OLD_URECOVERY
653 afs_snprintf(pbuffer, sizeof(pbuffer), "%s.DB0.OLD", ubik_dbase->pathName);
659 #ifndef OLD_URECOVERY
662 ubik_dbase->version.epoch = 0;
663 ubik_dbase->version.counter = 0;
664 ubik_print("Ubik: Synchronize database failed (error = %d)\n",
667 ubik_print("Ubik: Synchronize database completed\n");
669 udisk_Invalidate(ubik_dbase, 0); /* data has changed */
670 LWP_NoYieldSignal(&ubik_dbase->version);
673 #if defined(UBIK_PAUSE)
674 if (!(urecovery_state & UBIK_RECSYNCSITE))
675 continue; /* lost sync */
676 #endif /* UBIK_PAUSE */
677 if (!(urecovery_state & UBIK_RECHAVEDB))
678 continue; /* not ready */
680 /* If the database was newly initialized, then when we establish quorum, write
681 * a new label. This allows urecovery_AllBetter() to allow access for reads.
682 * Setting it to 2 also allows another site to come along with a newer
683 * database and overwrite this one.
685 if (ubik_dbase->version.epoch == 1) {
687 urecovery_AbortAll(ubik_dbase);
689 ubik_dbase->version.epoch = ubik_epochTime;
690 ubik_dbase->version.counter = 1;
692 (*ubik_dbase->setlabel) (ubik_dbase, 0, &ubik_dbase->version);
693 udisk_Invalidate(ubik_dbase, 0); /* data may have changed */
694 LWP_NoYieldSignal(&ubik_dbase->version);
698 /* Check the other sites and send the database to them if they
699 * do not have the current db.
701 if (!(urecovery_state & UBIK_RECSENTDB)) {
702 /* now propagate out new version to everyone else */
703 dbok = 1; /* start off assuming they all worked */
707 * Check if a write transaction is in progress. We can't send the
708 * db when a write is in progress here because the db would be
709 * obsolete as soon as it goes there. Also, ops after the begin
710 * trans would reach the recepient and wouldn't find a transaction
711 * pending there. Frankly, I don't think it's possible to get past
712 * the write-lock above if there is a write transaction in progress,
713 * but then, it won't hurt to check, will it?
715 if (ubik_dbase->flags & DBWRITING) {
720 while ((ubik_dbase->flags & DBWRITING) && (safety < 500)) {
722 /* sleep for a little while */
723 IOMGR_Select(0, 0, 0, 0, &tv);
730 for (ts = ubik_servers; ts; ts = ts->next) {
731 inAddr.s_addr = ts->addr[0];
733 ubik_dprint("recovery cannot send version to %s\n",
734 afs_inet_ntoa(inAddr.s_addr));
738 ubik_dprint("recovery sending version to %s\n",
739 afs_inet_ntoa(inAddr.s_addr));
740 if (vcmp(ts->version, ubik_dbase->version) != 0) {
741 ubik_dprint("recovery stating local database\n");
743 /* Rx code to do the Bulk Store */
744 code = (*ubik_dbase->stat) (ubik_dbase, 0, &ubikstat);
746 length = ubikstat.size;
748 rxcall = rx_NewCall(ts->disk_rxcid);
750 StartDISK_SendFile(rxcall, file, length,
751 &ubik_dbase->version);
753 ubik_dprint("StartDiskSendFile failed=%d\n",
760 sizeof(tbuffer) ? sizeof(tbuffer) : length);
762 (*ubik_dbase->read) (ubik_dbase, file,
763 tbuffer, offset, tlen);
764 if (nbytes != tlen) {
765 ubik_dprint("Local disk read error=%d\n",
769 nbytes = rx_Write(rxcall, tbuffer, tlen);
770 if (nbytes != tlen) {
771 ubik_dprint("Rx-write bulk error=%d\n", code =
778 code = EndDISK_SendFile(rxcall);
780 code = rx_EndCall(rxcall, code);
783 /* we set a new file, process its header */
784 ts->version = ubik_dbase->version;
789 /* mark file up to date */
795 urecovery_state |= UBIK_RECSENTDB;
801 ** send a Probe to all the network address of this server
802 ** Return 0 if success, else return 1
805 DoProbe(struct ubik_server *server)
807 struct rx_connection *conns[UBIK_MAX_INTERFACE_ADDR];
808 struct rx_connection *connSuccess = 0;
812 extern afs_int32 ubikSecIndex;
813 extern struct rx_securityClass *ubikSecClass;
815 for (i = 0; (addr = server->addr[i]) && (i < UBIK_MAX_INTERFACE_ADDR);
818 rx_NewConnection(addr, ubik_callPortal, DISK_SERVICE_ID,
819 ubikSecClass, ubikSecIndex);
821 /* user requirement to use only the primary interface */
822 if (ubikPrimaryAddrOnly) {
827 assert(i); /* at least one interface address for this server */
831 if (!multi_error) { /* first success */
832 addr = server->addr[multi_i]; /* successful interface addr */
834 if (server->disk_rxcid) /* destroy existing conn */
835 rx_DestroyConnection(server->disk_rxcid);
836 if (server->vote_rxcid)
837 rx_DestroyConnection(server->vote_rxcid);
839 /* make new connections */
840 server->disk_rxcid = conns[multi_i];
841 server->vote_rxcid = rx_NewConnection(addr, ubik_callPortal, VOTE_SERVICE_ID, ubikSecClass, ubikSecIndex); /* for vote reqs */
843 connSuccess = conns[multi_i];
844 strcpy(buffer, (char *)afs_inet_ntoa(server->addr[0]));
846 ("ubik:server %s is back up: will be contacted through %s\n",
847 buffer, afs_inet_ntoa(addr));
853 /* Destroy all connections except the one on which we succeeded */
854 for (j = 0; j < i; j++)
855 if (conns[j] != connSuccess)
856 rx_DestroyConnection(conns[j]);
859 ubik_dprint("ubik:server %s still down\n",
860 afs_inet_ntoa(server->addr[0]));
863 return 0; /* success */
865 return 1; /* failure */