/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998, 1999, 2000
 *	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 11.26 2000/08/03 15:32:18 ubell Exp $";
#endif /* not lint */

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

#include <errno.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 "log_auto.h"
#include "txn.h"
#include "txn_auto.h"
#include "log.h"

/*
 * __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 *, DBT *, DB_LSN *, db_recops, void *));
 */
int
__db_dispatch(dbenv, db, lsnp, redo, info)
	DB_ENV *dbenv;		/* The environment. */
	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;
{
	u_int32_t rectype, txnid;
	int make_call;

	memcpy(&rectype, db->data, sizeof(rectype));
	memcpy(&txnid, (u_int8_t *)db->data + sizeof(rectype), sizeof(txnid));
	make_call = 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:
		if (rectype == DB_log_register)
			return (dbenv->dtab[rectype](dbenv,
			    db, lsnp, redo, info));
		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.
		 */
		if (rectype == DB_log_register || rectype == DB_txn_ckp ||
		    rectype == DB_db_noop || rectype == DB_txn_child ||
		    (__db_txnlist_find(info, txnid) == DB_NOTFOUND &&
		    txnid != 0))
			make_call = 1;
		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_log_register || rectype == DB_txn_ckp ||
		    rectype == DB_db_noop ||
		    __db_txnlist_find(info, txnid) != DB_NOTFOUND)
			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
			return (dbenv->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 *), u_int32_t));
 */
int
__db_add_recovery(dbenv, func, ndx)
	DB_ENV *dbenv;
	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 >= dbenv->dtab_size) {
		nsize = ndx + 40;
		if ((ret = __os_realloc(dbenv,
		    nsize * sizeof(dbenv->dtab[0]), NULL, &dbenv->dtab)) != 0)
			return (ret);
		for (i = dbenv->dtab_size; i < nsize; ++i)
			dbenv->dtab[i] = NULL;
		dbenv->dtab_size = nsize;
	}

	dbenv->dtab[ndx] = func;
	return (0);
}

/*
 * __deprecated_recover --
 *	Stub routine for deprecated recovery functions.
 *
 * PUBLIC: int __deprecated_recover
 * PUBLIC:     __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
 */
int
__deprecated_recover(dbenv, dbtp, lsnp, op, info)
	DB_ENV *dbenv;
	DBT *dbtp;
	DB_LSN *lsnp;
	db_recops op;
	void *info;
{
	COMPQUIET(dbenv, NULL);
	COMPQUIET(dbtp, NULL);
	COMPQUIET(lsnp, NULL);
	COMPQUIET(op, 0);
	COMPQUIET(info, NULL);
	return (EINVAL);
}

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

	if ((ret = __os_malloc(dbenv, sizeof(DB_TXNHEAD), NULL, &headp)) != 0)
		return (ret);

	LIST_INIT(&headp->head);
	headp->maxid = 0;
	headp->generation = 1;

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

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

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

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

	elp->type = TXNLIST_TXNID;
	elp->u.t.txnid = txnid;
	if (txnid > hp->maxid)
		hp->maxid = txnid;
	elp->u.t.generation = hp->generation;

	return (0);
}

/* __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;

	hp = (DB_TXNHEAD *)listp;
	for (p = LIST_FIRST(&hp->head); 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); 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), NULL, &p)) != 0)
		return (ret);
	LIST_INSERT_HEAD(&hp->head, 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;

	hp = (DB_TXNHEAD *)listp;
	lp = (DB_LOG *)dbenv->lg_handle;
	while (hp != NULL &&
	    (p = LIST_FIRST(&hp->head)) != LIST_END(&hp->head)) {
		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(p->u.d.fname);
			break;
		case TXNLIST_LSN:
			__os_free(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(p, sizeof(DB_TXNLIST));
	}
	__os_free(listp, sizeof(DB_TXNHEAD));
}

/*
 * __db_txnlist_find --
 *	Checks to see if a txnid with the current generation is in the
 *	txnid list.  Txnid of 0 means the record was generated
 * 	while not in a transaction.
 *
 * PUBLIC: int __db_txnlist_find __P((void *, u_int32_t));
 */
int
__db_txnlist_find(listp, txnid)
	void *listp;
	u_int32_t txnid;
{
	DB_TXNLIST *entry;

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

/*
 * __db_txnlist_find_internal --
 *	Find an entry on the transaction list.
 * If the entry is not there or the list pointeris not initialized
 * we return NOTFOUND.  Currently we always call this with an
 * initialized list pointer but this keeps things general.
 *
 * PUBLIC: int __db_txnlist_find_internal __P((void *, db_txnlist_type,
 * PUBLIC:      u_int32_t, u_int8_t [DB_FILE_ID_LEN], DB_TXNLIST **));
 */
int
__db_txnlist_find_internal(listp, type, txnid, uid, txnlistp)
	void *listp;
	db_txnlist_type type;
	u_int32_t txnid;
	u_int8_t uid[DB_FILE_ID_LEN];
	DB_TXNLIST **txnlistp;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *p;

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

	for (p = LIST_FIRST(&hp->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;
			break;
			
		case TXNLIST_PGNO:
			if (memcmp(uid, p->u.p.uid, DB_FILE_ID_LEN) != 0)
				continue;
			
			break;
		default:
			DB_ASSERT(0);
		}
		/* Move it to head of list. */
		if (p != LIST_FIRST(&hp->head)) {
			LIST_REMOVE(p, links);
			LIST_INSERT_HEAD(&hp->head, p, links);
		}
		*txnlistp = p;
		return (0);
	}

	return (DB_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);
	    elp != NULL; elp = LIST_NEXT(elp, links))
		if (elp->type == TXNLIST_LSN)
			break;

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

	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),
			    NULL, &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_lsnhead --
 *	Return a pointer to the beginning of the lsn_array.
 *
 * PUBLIC: int __db_txnlist_lsnhead __P((void *, DB_LSN **));
 */
int
__db_txnlist_lsnhead(listp, lsnpp)
	void *listp;
	DB_LSN **lsnpp;
{
	DB_TXNHEAD *hp;
	DB_TXNLIST *elp;

	hp = (DB_TXNHEAD *)listp;

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

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

	*lsnpp = &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), NULL, &elp)) != 0)
		goto err;
	LIST_INSERT_HEAD(&hp->head, elp, links);

	if ((ret = __os_malloc(dbenv,
	    12 * sizeof(DB_LSN), NULL, &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_libmo -- add pages to the libmo 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 = __log_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 becasue 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_TXN *txn;
	DB_TXNLIST *elp;
	PAGE *pagep;
	db_pgno_t last_pgno, pgno;
	int 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);

	for (elp = LIST_FIRST(&hp->head);
	    elp != NULL; elp = LIST_NEXT(elp, links)) {
		if (elp->type != TXNLIST_PGNO)
			continue;

		if (in_recover) {
			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, 0, __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) {
			last_pgno = PGNO_INVALID;
			if (in_recover) {
				pgno = PGNO_BASE_MD;
				if ((ret = memp_fget(dbp->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 = memp_fget(dbp->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) 
						last_pgno = pgno;
					else {
						/*
						 * Starting the transaction
						 * is posponed till we know
						 * we have something to do.
						 */
						if (txn == NULL &&
						    (ret = txn_begin(dbenv,
						    NULL, &txn, 0)) != 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. */
						if ((ret =
						    __db_free(dbc, pagep)) != 0)
							goto err;
						put_page = 0;
					}
				}

				if (put_page == 1 &&
				    (ret = memp_fput(dbp->mpf,
				    pagep, DB_MPOOL_DIRTY)) != 0)
					goto err;
			}
			if (in_recover) {
				if (last_pgno == meta->free) {
done_it:
					if ((ret =
					    memp_fput(dbp->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.
					 */
					dbp->sync(dbp, 0);
					meta->free = last_pgno;
					if ((ret = memp_fput(dbp->mpf,
					    meta, DB_MPOOL_DIRTY)) != 0)
						goto err;
				}
			}
			if (dbc != NULL && (ret = dbc->c_close(dbc)) != 0)
				goto err;
			dbc = NULL;
		}
		if (in_recover && (t_ret = dbp->close(dbp, 0)) != 0 && ret == 0)
			ret = t_ret;
		dbp = NULL;
		__os_free(elp->u.p.fname, 0);
		__os_free(elp->u.p.pgno_array, 0);
		if (ret == ENOENT)
			ret = 0;
		else if (ret != 0)
			goto err;
	}

	if (txn != NULL) {
		ret = txn_commit(txn, 0);
		txn = NULL;
	}
err:
	if (dbc != NULL)
		(void) dbc->c_close(dbc);
	if (in_recover && 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.
 *
 * PUBLIC: int __db_txnlist_pgnoadd __P((DB_ENV *, DB_TXNHEAD *,
 * PUBLIC:      int32_t, u_int8_t [DB_FILE_ID_LEN], char *, db_pgno_t));
 */
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;
	int len, ret;

	elp = NULL;

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

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

		elp->u.p.maxentry = 0;
		elp->type = TXNLIST_PGNO;
		if ((ret = __os_malloc(dbenv,
		    8 * sizeof(db_pgno_t), NULL, &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), NULL, &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;

	hp = (DB_TXNHEAD *)listp;

	printf("Maxid: %lu Generation: %lu\n",
	    (u_long)hp->maxid, (u_long)hp->generation);
	for (p = LIST_FIRST(&hp->head); 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, 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
