/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2001
 *	Sleepycat Software.  All rights reserved.
 */
/*
 * Copyright (c) 1995, 1996
 *	The President and Fellows of Harvard University.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Margo Seltzer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "db_config.h"

#ifndef lint
static const char revid[] = "$Id: db_dispatch.c,v 11.82 2002/01/08 15:54:14 margo Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#endif

#include "db_int.h"
#include "db_page.h"
#include "db_dispatch.h"
#include "db_am.h"
#include "dbreg_auto.h"
#include "hash.h"
#include "hash_auto.h"
#include "txn.h"
#include "txn_auto.h"
#include "log.h"

static int __db_txnlist_find_internal __P((DB_ENV *, void *, db_txnlist_type,
		u_int32_t, u_int8_t [DB_FILE_ID_LEN], DB_TXNLIST **, int));
static int __db_txnlist_pgnoadd __P((DB_ENV *, DB_TXNHEAD *,
		int32_t, u_int8_t [DB_FILE_ID_LEN], char *, db_pgno_t));

/*
 * __db_dispatch --
 *
 * This is the transaction dispatch function used by the db access methods.
 * It is designed to handle the record format used by all the access
 * methods (the one automatically generated by the db_{h,log,read}.sh
 * scripts in the tools directory).  An application using a different
 * recovery paradigm will supply a different dispatch function to txn_open.
 *
 * PUBLIC: int __db_dispatch __P((DB_ENV *,
 * PUBLIC:     int (**)__P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *)),
 * PUBLIC:     size_t, DBT *, DB_LSN *, db_recops, void *));
 */
int
__db_dispatch(dbenv, dtab, dtabsize, db, lsnp, redo, info)
	DB_ENV *dbenv;		/* The environment. */
	int (**dtab)__P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
	size_t dtabsize;	/* Size of the dtab. */
	DBT *db;		/* The log record upon which to dispatch. */
	DB_LSN *lsnp;		/* The lsn of the record being dispatched. */
	db_recops redo;		/* Redo this op (or undo it). */
	void *info;
{
	DB_LSN prev_lsn;
	u_int32_t rectype, txnid;
	int make_call, ret;

	memcpy(&rectype, db->data, sizeof(rectype));
	memcpy(&txnid, (u_int8_t *)db->data + sizeof(rectype), sizeof(txnid));
	make_call = ret = 0;

	/*
	 * If we find a record that is in the user's number space and they
	 * have specified a recovery routine, let them handle it.  If they
	 * didn't specify a recovery routine, then we expect that they've
	 * followed all our rules and registered new recovery functions.
	 */
	switch (redo) {
	case DB_TXN_ABORT:
		/*
		 * XXX
		 * db_printlog depends on DB_TXN_ABORT not examining the TXN
		 * list.  If that ever changes, fix db_printlog too.
		 */
		make_call = 1;
		break;
	case DB_TXN_OPENFILES:
	case DB_TXN_POPENFILES:
		if (rectype == DB_dbreg_register || rectype == DB_txn_ckp)
			return (dbenv->dtab[rectype](dbenv,
			    db, lsnp, redo, info));
		else if (redo == DB_TXN_OPENFILES && txnid != 0) {
			/*
			 * We collect all the transactions that have
			 * "begin" records, those with no previous LSN,
			 * so that we do not abort partial transactions.
			 * These are known to be undone, otherwise the
			 * log would not have been freeable.
			 */
			memcpy(&prev_lsn,
			    (u_int8_t *)db->data +
			    sizeof(rectype) + sizeof(txnid), sizeof(prev_lsn));
			if (prev_lsn.file == 0)
				return (__db_txnlist_add(
				    dbenv, info, txnid, TXN_OK, NULL));
		}
		break;
	case DB_TXN_BACKWARD_ROLL:
		/*
		 * Running full recovery in the backward pass.  If we've
		 * seen this txnid before and added to it our commit list,
		 * then we do nothing during this pass, unless this is a child
		 * commit record, in which case we need to process it.  If
		 * we've never seen it, then we call the appropriate recovery
		 * routine.
		 *
		 * We need to always undo DB_db_noop records, so that we
		 * properly handle any aborts before the file was closed.
		 */
		switch(rectype) {
		case DB_txn_regop:
		case DB_dbreg_register:
		case DB_txn_ckp:
		case DB_db_noop:
		case DB_txn_child:
			make_call = 1;
			break;

		default:
			if (txnid != 0 && (ret =
			    __db_txnlist_find(dbenv,
			    info, txnid)) != TXN_COMMIT && ret != TXN_IGNORE) {
				/*
				 * If not found then, this is an incomplete
				 * abort.
				 */
				if (ret == TXN_NOTFOUND)
					return (__db_txnlist_add(dbenv,
					    info, txnid, TXN_IGNORE, lsnp));
				make_call = 1;
				if (ret == TXN_OK &&
				    (ret = __db_txnlist_update(dbenv,
				    info, txnid,
				    rectype == DB_txn_xa_regop ?
				    TXN_PREPARE : TXN_ABORT, NULL)) != 0)
					return (ret);
			}
		}
		break;
	case DB_TXN_FORWARD_ROLL:
		/*
		 * In the forward pass, if we haven't seen the transaction,
		 * do nothing, else recovery it.
		 *
		 * We need to always redo DB_db_noop records, so that we
		 * properly handle any commits after the file was closed.
		 */
		if (rectype == DB_dbreg_register ||
		    rectype == DB_txn_ckp ||
		    rectype == DB_db_noop ||
		    __db_txnlist_find(dbenv, info, txnid) == TXN_COMMIT)
			make_call = 1;
		else if (rectype == DB_ham_metagroup) {
			/* 
			 * We must make sure to apply this record after
			 * the DB file is created, which might not
			 * happen until the rollforward pass.
			 */
			make_call = 1;
			redo = DB_TXN_BACKWARD_ROLL;
		}
		break;
	case DB_TXN_APPLY:
		make_call = 1;
		break;
	default:
		return (__db_unknown_flag(dbenv, "__db_dispatch", redo));
	}

	if (make_call) {
		if (rectype >= DB_user_BEGIN && dbenv->tx_recover != NULL)
			return (dbenv->tx_recover(dbenv, db, lsnp, redo));
		else {
			/*
			 * The size of the dtab table argument is the same as
			 * the standard table, use the standard table's size
			 * as our sanity check.
			 */
			if ((dtab == NULL && rectype >= dbenv->dtab_size) ||
			    (dtab != NULL && rectype > dtabsize) ||
			    (dtab == NULL ?
			    dbenv->dtab[rectype] : dtab[rectype]) == NULL) {
				__db_err(dbenv,
				    "Illegal record type %lu in log",
				    (u_long)rectype);
				return (EINVAL);
			}
			return (dtab == NULL ?
			    dbenv->dtab[rectype](dbenv, db, lsnp, redo, info) :
			    dtab[rectype](dbenv, db, lsnp, redo, info));
		}
	}

	return (0);
}

/*
 * __db_add_recovery --
 *
 * PUBLIC: int __db_add_recovery __P((DB_ENV *,
 * PUBLIC:   int (***)(DB_ENV *, DBT *, DB_LSN *, db_recops, void *), size_t *,
 * PUBLIC:   int (*)(DB_ENV *, DBT *, DB_LSN *, db_recops, void *), u_int32_t));
 */
int
__db_add_recovery(dbenv, dtab, dtabsize, func, ndx)
	DB_ENV *dbenv;
	int (***dtab) __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
	size_t *dtabsize;
	int (*func) __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
	u_int32_t ndx;
{
	u_int32_t i, nsize;
	int ret;

	/* Check if we have to grow the table. */
	if (ndx >= *dtabsize) {
		nsize = ndx + 40;
		if ((ret =
		    __os_realloc(dbenv, nsize * sizeof((*dtab)[0]), dtab)) != 0)
			return (ret);
		for (i = *dtabsize; i < nsize; ++i)
			(*dtab)[i] = NULL;
		*dtabsize = nsize;
	}

	(*dtab)[ndx] = func;
	return (0);
}

/*
 * __db_txnlist_init --
 *	Initialize transaction linked list.
 *
 * PUBLIC: int __db_txnlist_init __P((DB_ENV *, u_int32_t, u_int32_t, void *));
 */
int
__db_txnlist_init(dbenv, low_txn, hi_txn, retp)
	DB_ENV *dbenv;
	u_int32_t low_txn, hi_txn;
	void *retp;
{
	DB_TXNHEAD *headp;
	u_int32_t tmp;
	int ret, size;

	/*
	 * Size a hash table.
	 *	If low is zero then we are being called during rollback
	 * and we need only one slot.
	 *	Hi maybe lower than low if we have recycled txnid's.
	 *	The numbers here are guesses about txn density, we can afford
	 * to look at a few entries in each slot.
	 */
	if (low_txn == 0)
		size = 1;
	else {
		if (hi_txn < low_txn) {
			tmp = hi_txn;
			hi_txn = low_txn;
			low_txn = tmp;
		}
		tmp = hi_txn - low_txn;
		/* See if we wrapped around. */
		if (tmp > (TXN_MAXIMUM - TXN_MINIMUM) / 2)
			tmp = (low_txn - TXN_MINIMUM) + (TXN_MAXIMUM - hi_txn);
		size = tmp / 5;
		if (size < 100)
			size = 100;
	}
	if ((ret = __os_malloc(dbenv,
	    sizeof(DB_TXNHEAD) + size * sizeof(headp->head), &headp)) != 0)
		return (ret);

	memset(headp, 0, sizeof(DB_TXNHEAD) + size * sizeof(headp->head));
	headp->maxid = hi_txn;
	headp->generation = 1;
	headp->nslots = size;
	ZERO_LSN(headp->maxlsn);
	ZERO_LSN(headp->ckplsn);

	*(void **)retp = headp;
	return (0);
}

/*
 * __db_txnlist_add --
 *	Add an element to our transaction linked list.
 *
 * PUBLIC: int __db_txnlist_add __P((DB_ENV *,
 * PUBLIC:     void *, u_int32_t, int32_t, DB_LSN *));
 */
int
__db_txnlist_add(dbenv, listp, txnid, status, lsn)
	DB_ENV *dbenv;
	void *listp;
	u_int32_t txnid;
	int32_t status;
	DB_LSN *lsn;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *elp;
	int ret;

	if ((ret = __os_malloc(dbenv, sizeof(DB_TXNLIST), &elp)) != 0)
		return (ret);

	hp = (DB_TXNHEAD *)listp;
	LIST_INSERT_HEAD(&hp->head[DB_TXNLIST_MASK(hp, txnid)], elp, links);

	elp->type = TXNLIST_TXNID;
	elp->u.t.txnid = txnid;
	elp->u.t.status = status;
	elp->u.t.generation = hp->generation;
	if (txnid > hp->maxid)
		hp->maxid = txnid;
	if (lsn != NULL && IS_ZERO_LSN(hp->maxlsn) && status == TXN_COMMIT)
		hp->maxlsn = *lsn;

	DB_ASSERT(lsn == NULL ||
	    status != TXN_COMMIT || log_compare(&hp->maxlsn, lsn) >= 0);

	return (0);
}

/*
 * __db_txnlist_remove --
 *	Remove an element from our transaction linked list.
 *
 * PUBLIC: int __db_txnlist_remove __P((DB_ENV *, void *, u_int32_t));
 */
int
__db_txnlist_remove(dbenv, listp, txnid)
	DB_ENV *dbenv;
	void *listp;
	u_int32_t txnid;
{
	DB_TXNLIST *entry;

	return (__db_txnlist_find_internal(dbenv,
	    listp, TXNLIST_TXNID, txnid,
	    NULL, &entry, 1) == TXN_NOTFOUND ? TXN_NOTFOUND : TXN_OK);
}

/*
 * __db_txnlist_ckp --
 *	Used to record the maximum checkpoint that will be retained
 * after recovery.  Typically this is simply the max checkpoint, but
 * if we are doing client replication recovery or timestamp-based
 * recovery, we are going to virtually truncate the log and we need
 * to retain the last checkpoint before the truncation point.
 *
 * PUBLIC: void __db_txnlist_ckp __P((DB_ENV *, void *, DB_LSN *));
 */
void
__db_txnlist_ckp(dbenv, listp, ckp_lsn)
	DB_ENV *dbenv;
	void *listp;
	DB_LSN *ckp_lsn;
{
	DB_TXNHEAD *hp;

	COMPQUIET(dbenv, NULL);

	hp = (DB_TXNHEAD *)listp;

	if (IS_ZERO_LSN(hp->ckplsn) && !IS_ZERO_LSN(hp->maxlsn) &&
	    log_compare(&hp->maxlsn, ckp_lsn) >= 0)
		hp->ckplsn = *ckp_lsn;
}

/* __db_txnlist_close --
 *
 *	Call this when we close a file.  It allows us to reconcile whether
 * we have done any operations on this file with whether the file appears
 * to have been deleted.  If you never do any operations on a file, then
 * we assume it's OK to appear deleted.
 *
 * PUBLIC: int __db_txnlist_close __P((void *, int32_t, u_int32_t));
 */
int
__db_txnlist_close(listp, lid, count)
	void *listp;
	int32_t lid;
	u_int32_t count;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;
	int i;

	if (listp == NULL)
		return (0);

	hp = (DB_TXNHEAD *)listp;
	for (i = 0; i < hp->nslots; i++)
		for (p = LIST_FIRST(&hp->head[i]);
		    p != NULL; p = LIST_NEXT(p, links)) {
			if (p->type == TXNLIST_DELETE)
				if (lid == p->u.d.fileid &&
				    !F_ISSET(&p->u.d, TXNLIST_FLAG_CLOSED)) {
					p->u.d.count += count;
					return (0);
				}
		}

	return (0);
}

/*
 * __db_txnlist_delete --
 *
 *	Record that a file was missing or deleted.  If the deleted
 * flag is set, then we've encountered a delete of a file, else we've
 * just encountered a file that is missing.  The lid is the log fileid
 * and is only meaningful if deleted is not equal to 0.
 *
 * PUBLIC: int __db_txnlist_delete __P((DB_ENV *,
 * PUBLIC:     void *, char *, u_int32_t, int));
 */
int
__db_txnlist_delete(dbenv, listp, name, lid, deleted)
	DB_ENV *dbenv;
	void *listp;
	char *name;
	u_int32_t lid;
	int deleted;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;
	int ret;

	hp = (DB_TXNHEAD *)listp;
	for (p = LIST_FIRST(&hp->head[DB_TXNLIST_MASK(hp, *name)]);
	    p != NULL; p = LIST_NEXT(p, links)) {
		if (p->type == TXNLIST_DELETE)
			if (strcmp(name, p->u.d.fname) == 0) {
				if (deleted)
					F_SET(&p->u.d, TXNLIST_FLAG_DELETED);
				else
					F_CLR(&p->u.d, TXNLIST_FLAG_CLOSED);
				return (0);
			}
	}

	/* Need to add it. */
	if ((ret = __os_malloc(dbenv, sizeof(DB_TXNLIST), &p)) != 0)
		return (ret);
	LIST_INSERT_HEAD(&hp->head[DB_TXNLIST_MASK(hp, *name)], p, links);

	p->type = TXNLIST_DELETE;
	p->u.d.flags = 0;
	if (deleted)
		F_SET(&p->u.d, TXNLIST_FLAG_DELETED);
	p->u.d.fileid = lid;
	p->u.d.count = 0;
	ret = __os_strdup(dbenv, name, &p->u.d.fname);

	return (ret);
}

/*
 * __db_txnlist_end --
 *	Discard transaction linked list. Print out any error messages
 * for deleted files.
 *
 * PUBLIC: void __db_txnlist_end __P((DB_ENV *, void *));
 */
void
__db_txnlist_end(dbenv, listp)
	DB_ENV *dbenv;
	void *listp;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;
	DB_LOG *lp;
	int i;

	if ((hp = (DB_TXNHEAD *)listp) == NULL)
		return;

	lp = (DB_LOG *)dbenv->lg_handle;
	for (i = 0; i < hp->nslots; i++)
		while (hp != NULL && (p = LIST_FIRST(&hp->head[i])) != NULL) {
			LIST_REMOVE(p, links);
			switch (p->type) {
			case TXNLIST_DELETE:
				/*
				 * If we have a file that is not deleted and has
				 * some operations, we flag the warning.  Since
				 * the file could still be open, we need to
				 * check the actual log table as well.
				 */
				if ((!F_ISSET(&p->u.d, TXNLIST_FLAG_DELETED) &&
				    p->u.d.count != 0) ||
				    (!F_ISSET(&p->u.d, TXNLIST_FLAG_CLOSED) &&
				    p->u.d.fileid !=
				    (int32_t)TXNLIST_INVALID_ID &&
				    p->u.d.fileid < lp->dbentry_cnt &&
				    lp->dbentry[p->u.d.fileid].count != 0))
					__db_err(dbenv, "warning: %s: %s",
					    p->u.d.fname, db_strerror(ENOENT));
				__os_freestr(dbenv, p->u.d.fname);
				break;
			case TXNLIST_LSN:
				__os_free(dbenv, p->u.l.lsn_array,
				    p->u.l.maxn * sizeof(DB_LSN));
				break;
			default:
				/*
				 * Possibly an incomplete DB_TXNLIST; just
				 * free it.
				 */
				break;
			}
			__os_free(dbenv, p, sizeof(DB_TXNLIST));
		}

	__os_free(dbenv,
	    listp, sizeof(DB_TXNHEAD) + sizeof(hp->head) * hp->nslots);
}

/*
 * __db_txnlist_find --
 *	Checks to see if a txnid with the current generation is in the
 *	txnid list.  This returns TXN_NOTFOUND if the item isn't in the
 *	list otherwise it returns (like __db_txnlist_find_internal)
 *	the status of the transaction.  A txnid of 0 means the record
 *	was generated while not in a transaction.
 *
 * PUBLIC: int __db_txnlist_find __P((DB_ENV *, void *, u_int32_t));
 */
int
__db_txnlist_find(dbenv, listp, txnid)
	DB_ENV *dbenv;
	void *listp;
	u_int32_t txnid;
{
	DB_TXNLIST *entry;

	if (txnid == 0)
		return (TXN_NOTFOUND);
	return (__db_txnlist_find_internal(dbenv, listp,
	     TXNLIST_TXNID, txnid, NULL, &entry, 0));
}

/*
 * __db_txnlist_update --
 *	Change the status of an existing transaction entry.
 *	Returns TXN_NOTFOUND if no such entry exists.
 *
 * PUBLIC: int __db_txnlist_update __P((DB_ENV *,
 * PUBLIC:     void *, u_int32_t, u_int32_t, DB_LSN *));
 */
int
__db_txnlist_update(dbenv, listp, txnid, status, lsn)
	DB_ENV *dbenv;
	void *listp;
	u_int32_t txnid;
	u_int32_t status;
	DB_LSN *lsn;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *elp;
	int ret;

	if (txnid == 0)
		return (TXN_NOTFOUND);
	hp = (DB_TXNHEAD *)listp;
	ret = __db_txnlist_find_internal(dbenv,
	    listp, TXNLIST_TXNID, txnid, NULL, &elp, 0);

	if (ret == TXN_NOTFOUND)
		return (ret);
	elp->u.t.status = status;

	if (lsn != NULL && IS_ZERO_LSN(hp->maxlsn) && status == TXN_COMMIT)
		hp->maxlsn = *lsn;

	return (ret);
}

/*
 * __db_txnlist_find_internal --
 *	Find an entry on the transaction list.  If the entry is not there or
 *	the list pointer is not initialized we return TXN_NOTFOUND.  If the
 *	item is found, we return the status.  Currently we always call this
 *	with an initialized list pointer but checking for NULL keeps it general.
 */
static int
__db_txnlist_find_internal(dbenv, listp, type, txnid, uid, txnlistp, delete)
	DB_ENV *dbenv;
	void *listp;
	db_txnlist_type type;
	u_int32_t txnid;
	u_int8_t uid[DB_FILE_ID_LEN];
	DB_TXNLIST **txnlistp;
	int delete;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;
	u_int32_t hash;
	struct __db_headlink *head;
	int ret;

	if ((hp = (DB_TXNHEAD *)listp) == NULL)
		return (TXN_NOTFOUND);

	switch (type) {
	case TXNLIST_TXNID:
		hash = txnid;
		break;
	case TXNLIST_PGNO:
		memcpy(&hash, uid, sizeof(hash));
		break;
	default:
		DB_ASSERT(0);
		ret = EINVAL;
	}

	head = &hp->head[DB_TXNLIST_MASK(hp, hash)];

	for (p = LIST_FIRST(head); p != NULL; p = LIST_NEXT(p, links)) {
		if (p->type != type)
			continue;
		switch (type) {
		case TXNLIST_TXNID:
			if (p->u.t.txnid != txnid ||
			    hp->generation != p->u.t.generation)
				continue;
			ret = p->u.t.status;
			break;

		case TXNLIST_PGNO:
			if (memcmp(uid, p->u.p.uid, DB_FILE_ID_LEN) != 0)
				continue;

			ret = 0;
			break;
		default:
			DB_ASSERT(0);
			ret = EINVAL;
		}
		if (delete == 1) {
			LIST_REMOVE(p, links);
			__os_free(dbenv, p, sizeof(DB_TXNLIST));
		} else if (p != LIST_FIRST(head)) {
			/* Move it to head of list. */
			LIST_REMOVE(p, links);
			LIST_INSERT_HEAD(head, p, links);
		}
		*txnlistp = p;
		return (ret);
	}

	return (TXN_NOTFOUND);
}

/*
 * __db_txnlist_gen --
 *	Change the current generation number.
 *
 * PUBLIC: void __db_txnlist_gen __P((void *, int));
 */
void
__db_txnlist_gen(listp, incr)
	void *listp;
	int incr;
{
	DB_TXNHEAD *hp;

	/*
	 * During recovery generation numbers keep track of how many "restart"
	 * checkpoints we've seen.  Restart checkpoints occur whenever we take
	 * a checkpoint and there are no outstanding transactions.  When that
	 * happens, we can reset transaction IDs back to 1.  It always happens
	 * at recovery and it prevents us from exhausting the transaction IDs
	 * name space.
	 */
	hp = (DB_TXNHEAD *)listp;
	hp->generation += incr;
}

#define	TXN_BUBBLE(AP, MAX) {						\
	int __j;							\
	DB_LSN __tmp;							\
									\
	for (__j = 0; __j < MAX - 1; __j++)				\
		if (log_compare(&AP[__j], &AP[__j + 1]) < 0) {		\
			__tmp = AP[__j];				\
			AP[__j] = AP[__j + 1];				\
			AP[__j + 1] = __tmp;				\
		}							\
}

/*
 * __db_txnlist_lsnadd --
 *	Add to or re-sort the transaction list lsn entry.  Note that since this
 *	is used during an abort, the __txn_undo code calls into the "recovery"
 *	subsystem explicitly, and there is only a single TXNLIST_LSN entry on
 *	the list.
 *
 * PUBLIC: int __db_txnlist_lsnadd __P((DB_ENV *, void *, DB_LSN *, u_int32_t));
 */
int
__db_txnlist_lsnadd(dbenv, listp, lsnp, flags)
	DB_ENV *dbenv;
	void *listp;
	DB_LSN *lsnp;
	u_int32_t flags;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *elp;
	int i, ret;

	hp = (DB_TXNHEAD *)listp;

	for (elp = LIST_FIRST(&hp->head[0]);
	    elp != NULL; elp = LIST_NEXT(elp, links))
		if (elp->type == TXNLIST_LSN)
			break;

	if (elp == NULL)
		return (DB_SURPRISE_KID);

	if (LF_ISSET(TXNLIST_NEW)) {
		if (elp->u.l.ntxns >= elp->u.l.maxn) {
			if ((ret = __os_realloc(dbenv,
			    2 * elp->u.l.maxn * sizeof(DB_LSN),
			    &elp->u.l.lsn_array)) != 0)
				return (ret);
			elp->u.l.maxn *= 2;
		}
		elp->u.l.lsn_array[elp->u.l.ntxns++] = *lsnp;
	} else
		/* Simply replace the 0th element. */
		elp->u.l.lsn_array[0] = *lsnp;

	/*
	 * If we just added a new entry and there may be NULL entries, so we
	 * have to do a complete bubble sort, not just trickle a changed entry
	 * around.
	 */
	for (i = 0; i < (!LF_ISSET(TXNLIST_NEW) ? 1 : elp->u.l.ntxns); i++)
		TXN_BUBBLE(elp->u.l.lsn_array, elp->u.l.ntxns);

	*lsnp = elp->u.l.lsn_array[0];

	return (0);
}

/*
 * __db_txnlist_lsninit --
 *	Initialize a transaction list with an lsn array entry.
 *
 * PUBLIC: int __db_txnlist_lsninit __P((DB_ENV *, DB_TXNHEAD *, DB_LSN *));
 */
int
__db_txnlist_lsninit(dbenv, hp, lsnp)
	DB_ENV *dbenv;
	DB_TXNHEAD *hp;
	DB_LSN *lsnp;
{
	DB_TXNLIST *elp;
	int ret;

	elp = NULL;

	if ((ret = __os_malloc(dbenv, sizeof(DB_TXNLIST), &elp)) != 0)
		goto err;
	LIST_INSERT_HEAD(&hp->head[0], elp, links);

	if ((ret = __os_malloc(dbenv,
	    12 * sizeof(DB_LSN), &elp->u.l.lsn_array)) != 0)
		goto err;
	elp->type = TXNLIST_LSN;
	elp->u.l.maxn = 12;
	elp->u.l.ntxns = 1;
	elp->u.l.lsn_array[0] = *lsnp;

	return (0);

err:	__db_txnlist_end(dbenv, hp);
	return (ret);
}

/*
 * __db_add_limbo -- add pages to the limbo list.
 *	Get the file information and call pgnoadd for each page.
 *
 * PUBLIC: int __db_add_limbo __P((DB_ENV *,
 * PUBLIC:      void *, int32_t, db_pgno_t, int32_t));
 */
int
__db_add_limbo(dbenv, info, fileid, pgno, count)
	DB_ENV *dbenv;
	void *info;
	int32_t fileid;
	db_pgno_t pgno;
	int32_t count;
{
	DB_LOG *dblp;
	FNAME *fnp;
	int ret;

	dblp = dbenv->lg_handle;
	if ((ret = __dbreg_lid_to_fname(dblp, fileid, &fnp)) != 0)
		return (ret);

	do {
		if ((ret =
		    __db_txnlist_pgnoadd(dbenv, info, fileid, fnp->ufid,
		    R_ADDR(&dblp->reginfo, fnp->name_off), pgno)) != 0)
			return (ret);
		pgno++;
	} while (--count != 0);

	return (0);
}

/*
 * __db_do_the_limbo -- move pages from limbo to free.
 *
 * If we are in recovery we add things to the free list without logging
 * because we want to incrementaly apply logs that may be generated on
 * another copy of this environment.  Otherwise we just call __db_free to
 * put the pages on the free list and log the activity.
 *
 * PUBLIC: int __db_do_the_limbo __P((DB_ENV *, DB_TXNHEAD *));
 */
int
__db_do_the_limbo(dbenv, hp)
	DB_ENV *dbenv;
	DB_TXNHEAD *hp;
{
	DB *dbp;
	DBC *dbc;
	DBMETA *meta;
	DB_MPOOLFILE *mpf;
	DB_TXN *txn;
	DB_TXNLIST *elp;
	PAGE *pagep;
	db_pgno_t last_pgno, pgno;
	int h, i, in_recover, put_page, ret, t_ret;

	dbp = NULL;
	dbc = NULL;
	txn = NULL;
	ret = 0;

	/* Are we in recovery? */
	in_recover = F_ISSET((DB_LOG *)dbenv->lg_handle, DBLOG_RECOVER) ? 1 : 0;

	for (h = 0; h < hp->nslots; h++)
	for (elp = LIST_FIRST(&hp->head[h]);
	    elp != NULL; elp = LIST_NEXT(elp, links)) {
		if (elp->type != TXNLIST_PGNO)
			continue;

		if (in_recover != 0) {
			if ((ret = db_create(&dbp, dbenv, 0)) != 0)
				goto err;

			/*
			 * It is ok if the file is nolonger there.
			 */
			dbp->type = DB_UNKNOWN;
			ret = __db_dbopen(dbp, elp->u.p.fname,
			    DB_ODDFILESIZE, __db_omode("rw----"), 0);
		} else {
			/*
			 * If we are in transaction undo, then we know
			 * the fileid is still correct.
			 */
			if ((ret =
			    __db_fileid_to_db(dbenv, &dbp,
			    elp->u.p.fileid, 0)) != 0 && ret != DB_DELETED)
				goto err;
			/* File is being destroyed. */
			if (F_ISSET(dbp, DB_AM_DISCARD))
				ret = DB_DELETED;
		}
		/*
		 * Verify that we are opening the same file that we were
		 * referring to when we wrote this log record.
		 */
		if (ret == 0 &&
		    memcmp(elp->u.p.uid, dbp->fileid, DB_FILE_ID_LEN) == 0) {
			mpf = dbp->mpf;
			last_pgno = PGNO_INVALID;

recover:		if (in_recover != 0) {
				pgno = PGNO_BASE_MD;
				if ((ret = mpf->get(
				    mpf, &pgno, 0, (PAGE **)&meta)) != 0)
					goto err;
				last_pgno = meta->free;
				/*
				 * Check to see if the head of the free
				 * list is any of the pages we are about
				 * to link in.  We could have crashed
				 * after linking them in and before writing
				 * a checkpoint.
				 * It may not be the last one since
				 * any page may get reallocated before here.
				 */
				if (last_pgno != PGNO_INVALID)
					for (i = 0; i < elp->u.p.nentries; i++)
						if (last_pgno
						     == elp->u.p.pgno_array[i])
							goto done_it;
			}

			for (i = 0; i < elp->u.p.nentries; i++) {
				pgno = elp->u.p.pgno_array[i];
				if ((ret = mpf->get(mpf,
				    &pgno, DB_MPOOL_CREATE, &pagep)) != 0)
					goto err;

				put_page = 1;
				if (IS_ZERO_LSN(LSN(pagep))) {
					P_INIT(pagep, dbp->pgsize,
					    pgno, PGNO_INVALID,
					    last_pgno, 0, P_INVALID);

					if (in_recover != 0) {
						LSN(pagep) = LSN(meta);
						last_pgno = pgno;
					} else {
						/*
						 * Starting the transaction
						 * is postponed until we know
						 * we have something to do.
						 */
						if (txn == NULL &&
						    (ret =
						    __txn_compensate_begin(
						    dbenv, &txn)) != 0)
							goto err;

						if (dbc == NULL &&
						    (ret = dbp->cursor(dbp,
						    txn, &dbc, 0)) != 0)
							goto err;
						/* Turn off locking. */
						F_SET(dbc, DBC_COMPENSATE);

						/* __db_free puts the page. */
						ret = __db_free(dbc, pagep);
						if (ret == EIO) {
							/*
							 * Log is probably
							 * out of space.
							 */
							in_recover = 2;
							(void)dbc->c_close(dbc);
							dbc = NULL;
							(void)txn->abort(txn);
							txn = NULL;
							ret = 0;
							goto recover;
						}
						put_page = 0;
					}
				}

				if (put_page == 1 && (ret =
				    mpf->put(mpf, pagep, DB_MPOOL_DIRTY)) != 0)
					goto err;
			}
			if (in_recover != 0) {
				if (last_pgno == meta->free) {
done_it:				if ((ret = mpf->put(mpf, meta, 0)) != 0)
						goto err;
				} else {
					/*
					 * Flush the new free list then
					 * update the metapage.  This is
					 * unlogged so we cannot have the
					 * metapage pointing at pages that
					 * are not on disk.
					 */
					if (in_recover == 2)
						__db_err(dbenv,
				"Error in abort of an allocation, flushing");
					dbp->sync(dbp, 0);
					meta->free = last_pgno;
					if ((ret = mpf->put(
					    mpf, meta, DB_MPOOL_DIRTY)) != 0)
						goto err;
				}
			}
			if (dbc != NULL && (ret = dbc->c_close(dbc)) != 0)
				goto err;
			dbc = NULL;
		}
		if (in_recover == 1
		    && (t_ret = dbp->close(dbp, 0)) != 0 && ret == 0)
			ret = t_ret;
		dbp = NULL;
		__os_free(dbenv, elp->u.p.fname, 0);
		__os_free(dbenv, elp->u.p.pgno_array, 0);
		if (ret == ENOENT)
			ret = 0;
		else if (ret != 0)
			goto err;
	}

	if (txn != NULL) {
		ret = txn->commit(txn, DB_TXN_NOSYNC);
		txn = NULL;
	}

err:	if (ret == DB_DELETED)
		ret = 0;

	if (ret != 0) {
		__db_err(dbenv, "Fatal error in abort of an allocation");
		ret = __db_panic(dbenv, ret);
	}

	if (dbc != NULL)
		(void)dbc->c_close(dbc);
	if (in_recover == 1 && dbp != NULL)
		(void)dbp->close(dbp, 0);
	if (txn != NULL)
		(void)txn->abort(txn);

	return (ret);
}

#define	DB_TXNLIST_MAX_PGNO	8		/* A nice even number. */

/*
 * __db_txnlist_pgnoadd --
 *	Find the txnlist entry for a file and add this pgno, or add the list
 *	entry for the file and then add the pgno.
 */
static int
__db_txnlist_pgnoadd(dbenv, hp, fileid, uid, fname, pgno)
	DB_ENV *dbenv;
	DB_TXNHEAD *hp;
	int32_t fileid;
	u_int8_t uid[DB_FILE_ID_LEN];
	char *fname;
	db_pgno_t pgno;
{
	DB_TXNLIST *elp;
	u_int32_t hash;
	int len, ret;

	elp = NULL;

	if (__db_txnlist_find_internal(dbenv, hp,
	    TXNLIST_PGNO, 0, uid, &elp, 0) != 0) {
		if ((ret =
		    __os_malloc(dbenv, sizeof(DB_TXNLIST), &elp)) != 0)
			goto err;
		memcpy(&hash, uid, sizeof(hash));
		LIST_INSERT_HEAD(
		    &hp->head[DB_TXNLIST_MASK(hp, hash)], elp, links);
		elp->u.p.fileid = fileid;
		memcpy(elp->u.p.uid, uid, DB_FILE_ID_LEN);

		len = strlen(fname) + 1;
		if ((ret = __os_malloc(dbenv, len, &elp->u.p.fname)) != 0)
			goto err;
		memcpy(elp->u.p.fname, fname, len);

		elp->u.p.maxentry = 0;
		elp->type = TXNLIST_PGNO;
		if ((ret = __os_malloc(dbenv,
		    8 * sizeof(db_pgno_t), &elp->u.p.pgno_array)) != 0)
			goto err;
		elp->u.p.maxentry = DB_TXNLIST_MAX_PGNO;
		elp->u.p.nentries = 0;
	} else if (elp->u.p.nentries == elp->u.p.maxentry) {
		elp->u.p.maxentry <<= 1;
		if ((ret = __os_realloc(dbenv, elp->u.p.maxentry *
		    sizeof(db_pgno_t), &elp->u.p.pgno_array)) != 0)
			goto err;
	}

	elp->u.p.pgno_array[elp->u.p.nentries++] = pgno;

	return (0);

err:	__db_txnlist_end(dbenv, hp);
	return (ret);
}

#ifdef DEBUG
/*
 * __db_txnlist_print --
 *	Print out the transaction list.
 *
 * PUBLIC: void __db_txnlist_print __P((void *));
 */
void
__db_txnlist_print(listp)
	void *listp;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;
	int i;

	hp = (DB_TXNHEAD *)listp;

	printf("Maxid: %lu Generation: %lu\n",
	    (u_long)hp->maxid, (u_long)hp->generation);
	for (i = 0; i < hp->nslots; i++)
	for (p = LIST_FIRST(&hp->head[i]); p != NULL; p = LIST_NEXT(p, links)) {
		switch (p->type) {
		case TXNLIST_TXNID:
			printf("TXNID: %lu(%lu)\n",
			    (u_long)p->u.t.txnid, (u_long)p->u.t.generation);
			break;
		case TXNLIST_DELETE:
			printf("FILE: %s id=%d ops=%d %s %s\n",
			    p->u.d.fname, (int)p->u.d.fileid, p->u.d.count,
			    F_ISSET(&p->u.d, TXNLIST_FLAG_DELETED) ?
			    "(deleted)" : "(missing)",
			    F_ISSET(&p->u.d, TXNLIST_FLAG_CLOSED) ?
			    "(closed)" : "(open)");

			break;
		default:
			printf("Unrecognized type: %d\n", p->type);
			break;
		}
	}
}
#endif
