Update.

[glibc.git] / db2 / hash / hash_rec.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998
 *      Sleepycat Software.  All rights reserved.
 */
/*
 * Copyright (c) 1995, 1996
 *      Margo Seltzer.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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 "config.h"

#ifndef lint
static const char sccsid[] = "@(#)hash_rec.c    10.19 (Sleepycat) 5/23/98";
#endif /* not lint */

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

#include <errno.h>
#include <string.h>
#endif

#include "db_int.h"
#include "shqueue.h"
#include "db_page.h"
#include "hash.h"
#include "btree.h"
#include "log.h"
#include "common_ext.h"

/*
 * __ham_insdel_recover --
 *
 * PUBLIC: int __ham_insdel_recover
 * PUBLIC:     __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_insdel_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_insdel_args *argp;
        DB *mdbp, *file_dbp;
        DB_MPOOLFILE *mpf;
        HTAB *hashp;
        PAGE *pagep;
        u_int32_t op;
        int cmp_n, cmp_p, getmeta, ret;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_insdel_print);
        REC_INTRO(__ham_insdel_read);

        ret = memp_fget(mpf, &argp->pgno, 0, &pagep);
        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        *lsnp = argp->prev_lsn;
                        ret = 0;
                        goto out;
                } else if ((ret = memp_fget(mpf, &argp->pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;

        cmp_n = log_compare(lsnp, &LSN(pagep));
        cmp_p = log_compare(&LSN(pagep), &argp->pagelsn);
        /*
         * Two possible things going on:
         * redo a delete/undo a put: delete the item from the page.
         * redo a put/undo a delete: add the item to the page.
         * If we are undoing a delete, then the information logged is the
         * entire entry off the page, not just the data of a dbt.  In
         * this case, we want to copy it back onto the page verbatim.
         * We do this by calling __putitem with the type H_OFFPAGE instead
         * of H_KEYDATA.
         */
        op = OPCODE_OF(argp->opcode);

        if ((op == DELPAIR && cmp_n == 0 && !redo) ||
            (op == PUTPAIR && cmp_p == 0 && redo)) {
                /*
                 * Need to redo a PUT or undo a delete.  If we are undoing a
                 * delete, we've got to restore the item back to its original
                 * position.  That's a royal pain in the butt (because we do
                 * not store item lengths on the page), but there's no choice.
                 */
                if (op != DELPAIR ||
                    argp->ndx == (u_int32_t)H_NUMPAIRS(pagep)) {
                        __ham_putitem(pagep, &argp->key,
                            !redo || PAIR_ISKEYBIG(argp->opcode) ?
                            H_OFFPAGE : H_KEYDATA);
                        __ham_putitem(pagep, &argp->data,
                            !redo || PAIR_ISDATABIG(argp->opcode) ?
                            H_OFFPAGE : H_KEYDATA);
                } else
                        (void) __ham_reputpair(pagep, hashp->hdr->pagesize,
                            argp->ndx, &argp->key, &argp->data);

                LSN(pagep) = redo ? *lsnp : argp->pagelsn;
                if ((ret = __ham_put_page(file_dbp, pagep, 1)) != 0)
                        goto out;

        } else if ((op == DELPAIR && cmp_p == 0 && redo)
            || (op == PUTPAIR && cmp_n == 0 && !redo)) {
                /* Need to undo a put or redo a delete. */
                __ham_dpair(file_dbp, pagep, argp->ndx);
                LSN(pagep) = redo ? *lsnp : argp->pagelsn;
                if ((ret = __ham_put_page(file_dbp, (PAGE *)pagep, 1)) != 0)
                        goto out;
        } else
                if ((ret = __ham_put_page(file_dbp, (PAGE *)pagep, 0)) != 0)
                        goto out;

        /* Return the previous LSN. */
        *lsnp = argp->prev_lsn;

out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;
}

/*
 * __ham_newpage_recover --
 *      This log message is used when we add/remove overflow pages.  This
 *      message takes care of the pointer chains, not the data on the pages.
 *
 * PUBLIC: int __ham_newpage_recover
 * PUBLIC:     __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_newpage_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_newpage_args *argp;
        DB *mdbp, *file_dbp;
        DB_MPOOLFILE *mpf;
        HTAB *hashp;
        PAGE *pagep;
        int cmp_n, cmp_p, change, getmeta, ret;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_newpage_print);
        REC_INTRO(__ham_newpage_read);

        ret = memp_fget(mpf, &argp->new_pgno, 0, &pagep);
        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        ret = 0;
                        goto ppage;
                } else if ((ret = memp_fget(mpf, &argp->new_pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;

        /*
         * There are potentially three pages we need to check: the one
         * that we created/deleted, the one before it and the one after
         * it.
         */

        cmp_n = log_compare(lsnp, &LSN(pagep));
        cmp_p = log_compare(&LSN(pagep), &argp->pagelsn);
        change = 0;

        if ((cmp_p == 0 && redo && argp->opcode == PUTOVFL) ||
            (cmp_n == 0 && !redo && argp->opcode == DELOVFL)) {
                /* Redo a create new page or undo a delete new page. */
                P_INIT(pagep, file_dbp->pgsize, argp->new_pgno,
                    argp->prev_pgno, argp->next_pgno, 0, P_HASH);
                change = 1;
        } else if ((cmp_p == 0 && redo && argp->opcode == DELOVFL) ||
            (cmp_n == 0 && !redo && argp->opcode == PUTOVFL)) {
                /*
                 * Redo a delete or undo a create new page.  All we
                 * really need to do is change the LSN.
                 */
                change = 1;
        }

        if (!change) {
                if ((ret = __ham_put_page(file_dbp, (PAGE *)pagep, 0)) != 0)
                        goto out;
        } else {
                LSN(pagep) = redo ? *lsnp : argp->pagelsn;
                if ((ret = __ham_put_page(file_dbp, (PAGE *)pagep, 1)) != 0)
                        goto out;
        }

        /* Now do the prev page. */
ppage:  if (argp->prev_pgno != PGNO_INVALID) {
                ret = memp_fget(mpf, &argp->prev_pgno, 0, &pagep);

                if (ret != 0) {
                        if (!redo) {
                                /*
                                 * We are undoing and the page doesn't exist.
                                 * That is equivalent to having a pagelsn of 0,
                                 * so we would not have to undo anything.  In
                                 * this case, don't bother creating a page.
                                 */
                                ret = 0;
                                goto npage;
                        } else if ((ret =
                            memp_fget(mpf, &argp->prev_pgno,
                            DB_MPOOL_CREATE, &pagep)) != 0)
                                goto out;
                }

                cmp_n = log_compare(lsnp, &LSN(pagep));
                cmp_p = log_compare(&LSN(pagep), &argp->prevlsn);
                change = 0;

                if ((cmp_p == 0 && redo && argp->opcode == PUTOVFL) ||
                    (cmp_n == 0 && !redo && argp->opcode == DELOVFL)) {
                        /* Redo a create new page or undo a delete new page. */
                        pagep->next_pgno = argp->new_pgno;
                        change = 1;
                } else if ((cmp_p == 0 && redo && argp->opcode == DELOVFL) ||
                    (cmp_n == 0 && !redo && argp->opcode == PUTOVFL)) {
                        /* Redo a delete or undo a create new page. */
                        pagep->next_pgno = argp->next_pgno;
                        change = 1;
                }

                if (!change) {
                        if ((ret = __ham_put_page(file_dbp, (PAGE *)pagep, 0)) != 0)
                                goto out;
                } else {
                        LSN(pagep) = redo ? *lsnp : argp->prevlsn;
                        if ((ret = __ham_put_page(file_dbp, (PAGE *)pagep, 1)) != 0)
                                goto out;
                }
        }

        /* Now time to do the next page */
npage:  if (argp->next_pgno != PGNO_INVALID) {
                ret = memp_fget(mpf, &argp->next_pgno, 0, &pagep);

                if (ret != 0) {
                        if (!redo) {
                                /*
                                 * We are undoing and the page doesn't exist.
                                 * That is equivalent to having a pagelsn of 0,
                                 * so we would not have to undo anything.  In
                                 * this case, don't bother creating a page.
                                 */
                                *lsnp = argp->prev_lsn;
                                ret = 0;
                                goto out;
                        } else if ((ret =
                            memp_fget(mpf, &argp->next_pgno,
                            DB_MPOOL_CREATE, &pagep)) != 0)
                                goto out;
                }

                cmp_n = log_compare(lsnp, &LSN(pagep));
                cmp_p = log_compare(&LSN(pagep), &argp->nextlsn);
                change = 0;

                if ((cmp_p == 0 && redo && argp->opcode == PUTOVFL) ||
                    (cmp_n == 0 && !redo && argp->opcode == DELOVFL)) {
                        /* Redo a create new page or undo a delete new page. */
                        pagep->prev_pgno = argp->new_pgno;
                        change = 1;
                } else if ((cmp_p == 0 && redo && argp->opcode == DELOVFL) ||
                    (cmp_n == 0 && !redo && argp->opcode == PUTOVFL)) {
                        /* Redo a delete or undo a create new page. */
                        pagep->prev_pgno = argp->prev_pgno;
                        change = 1;
                }

                if (!change) {
                        if ((ret =
                            __ham_put_page(file_dbp, (PAGE *)pagep, 0)) != 0)
                                goto out;
                } else {
                        LSN(pagep) = redo ? *lsnp : argp->nextlsn;
                        if ((ret =
                            __ham_put_page(file_dbp, (PAGE *)pagep, 1)) != 0)
                                goto out;
                }
        }
        *lsnp = argp->prev_lsn;

out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;
}


/*
 * __ham_replace_recover --
 *      This log message refers to partial puts that are local to a single
 *      page.  You can think of them as special cases of the more general
 *      insdel log message.
 *
 * PUBLIC: int __ham_replace_recover
 * PUBLIC:    __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_replace_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_replace_args *argp;
        DB *mdbp, *file_dbp;
        DB_MPOOLFILE *mpf;
        DBT dbt;
        HTAB *hashp;
        PAGE *pagep;
        int32_t grow;
        int change, cmp_n, cmp_p, getmeta, ret;
        u_int8_t *hk;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_replace_print);
        REC_INTRO(__ham_replace_read);

        ret = memp_fget(mpf, &argp->pgno, 0, &pagep);
        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        *lsnp = argp->prev_lsn;
                        ret = 0;
                        goto out;
                } else if ((ret = memp_fget(mpf, &argp->pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;

        cmp_n = log_compare(lsnp, &LSN(pagep));
        cmp_p = log_compare(&LSN(pagep), &argp->pagelsn);

        if (cmp_p == 0 && redo) {
                change = 1;
                /* Reapply the change as specified. */
                dbt.data = argp->newitem.data;
                dbt.size = argp->newitem.size;
                grow = argp->newitem.size - argp->olditem.size;
                LSN(pagep) = *lsnp;
        } else if (cmp_n == 0 && !redo) {
                change = 1;
                /* Undo the already applied change. */
                dbt.data = argp->olditem.data;
                dbt.size = argp->olditem.size;
                grow = argp->olditem.size - argp->newitem.size;
                LSN(pagep) = argp->pagelsn;
        } else {
                change = 0;
                grow = 0;
        }

        if (change) {
                __ham_onpage_replace(pagep,
                    file_dbp->pgsize, argp->ndx, argp->off, grow, &dbt);
                if (argp->makedup) {
                        hk = P_ENTRY(pagep, argp->ndx);
                        if (redo)
                                HPAGE_PTYPE(hk) = H_DUPLICATE;
                        else
                                HPAGE_PTYPE(hk) = H_KEYDATA;
                }
        }

        if ((ret = __ham_put_page(file_dbp, pagep, change)) != 0)
                goto out;

        *lsnp = argp->prev_lsn;

out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;
}

/*
 * __ham_newpgno_recover --
 *      This log message is used when allocating or deleting an overflow
 *      page.  It takes care of modifying the meta data.
 *
 * PUBLIC: int __ham_newpgno_recover
 * PUBLIC:    __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_newpgno_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_newpgno_args *argp;
        DB *mdbp, *file_dbp;
        DB_MPOOLFILE *mpf;
        HTAB *hashp;
        PAGE *pagep;
        int change, cmp_n, cmp_p, getmeta, ret;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_newpgno_print);
        REC_INTRO(__ham_newpgno_read);

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;

        /*
         * There are two phases to the recovery here.  First we need
         * to update the meta data; then we need to update the page.
         * We'll do the meta-data first.
         */
        cmp_n = log_compare(lsnp, &hashp->hdr->lsn);
        cmp_p = log_compare(&hashp->hdr->lsn, &argp->metalsn);

        change = 0;
        if ((cmp_p == 0 && redo && argp->opcode == ALLOCPGNO) ||
            (cmp_n == 0 && !redo && argp->opcode == DELPGNO)) {
                /* Need to redo an allocation or undo a deletion. */
                hashp->hdr->last_freed = argp->free_pgno;
                if (redo && argp->old_pgno != 0) /* Must be ALLOCPGNO */
                        hashp->hdr->spares[hashp->hdr->ovfl_point]++;
                change = 1;
        } else if (cmp_p == 0 && redo && argp->opcode == DELPGNO) {
                /* Need to redo a deletion */
                hashp->hdr->last_freed = argp->pgno;
                change = 1;
        } else if (cmp_n == 0 && !redo && argp->opcode == ALLOCPGNO) {
                /* undo an allocation. */
                if (argp->old_pgno == 0)
                        hashp->hdr->last_freed = argp->pgno;
                else {
                        hashp->hdr->spares[hashp->hdr->ovfl_point]--;
                        hashp->hdr->last_freed = 0;
                }
                change = 1;
        }
        if (change) {
                hashp->hdr->lsn = redo ? *lsnp : argp->metalsn;
                F_SET(file_dbp, DB_HS_DIRTYMETA);
        }


        /* Now check the newly allocated/freed page. */
        ret = memp_fget(mpf, &argp->pgno, 0, &pagep);

        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        *lsnp = argp->prev_lsn;
                        ret = 0;
                        goto out;
                } else if ((ret = memp_fget(mpf, &argp->pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        cmp_n = log_compare(lsnp, &LSN(pagep));
        cmp_p = log_compare(&LSN(pagep), &argp->pagelsn);

        change = 0;
        if (cmp_p == 0 && redo && argp->opcode == ALLOCPGNO) {
                /* Need to redo an allocation. */
                P_INIT(pagep, file_dbp->pgsize, argp->pgno, PGNO_INVALID,
                    PGNO_INVALID, 0, argp->new_type);
                change = 1;
        } else if (cmp_n == 0 && !redo && argp->opcode == DELPGNO) {
                /* Undoing a delete. */
                P_INIT(pagep, file_dbp->pgsize, argp->pgno, PGNO_INVALID,
                    argp->old_pgno, 0, argp->old_type);
                change = 1;
        } else if ((cmp_p == 0 && redo && argp->opcode == DELPGNO) ||
            (cmp_n == 0 && !redo && argp->opcode == ALLOCPGNO)) {
                /* Need to redo a deletion or undo an allocation. */
                NEXT_PGNO(pagep) = argp->free_pgno;
                TYPE(pagep) = P_INVALID;
                change = 1;
        }
        if (change)
                LSN(pagep) = redo ? *lsnp : argp->pagelsn;

        if ((ret = __ham_put_page(file_dbp, pagep, change)) != 0)
                goto out;

        *lsnp = argp->prev_lsn;

out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;

}

/*
 * __ham_splitmeta_recover --
 *      This is the meta-data part of the split.  Records the new and old
 *      bucket numbers and the new/old mask information.
 *
 * PUBLIC: int __ham_splitmeta_recover
 * PUBLIC:    __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_splitmeta_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_splitmeta_args *argp;
        DB *mdbp, *file_dbp;
        DB_MPOOLFILE *mpf;
        HTAB *hashp;
        int change, cmp_n, cmp_p, getmeta, ret;
        u_int32_t pow;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_splitmeta_print);
        REC_INTRO(__ham_splitmeta_read);

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;

        /*
         * There are two phases to the recovery here.  First we need
         * to update the meta data; then we need to update the page.
         * We'll do the meta-data first.
         */
        cmp_n = log_compare(lsnp, &hashp->hdr->lsn);
        cmp_p = log_compare(&hashp->hdr->lsn, &argp->metalsn);

        change = 0;
        if (cmp_p == 0 && redo) {
                /* Need to redo the split information. */
                hashp->hdr->max_bucket = argp->bucket + 1;
                pow = __db_log2(hashp->hdr->max_bucket + 1);
                if (pow > hashp->hdr->ovfl_point) {
                        hashp->hdr->spares[pow] =
                                hashp->hdr->spares[hashp->hdr->ovfl_point];
                        hashp->hdr->ovfl_point = pow;
                }
                if (hashp->hdr->max_bucket > hashp->hdr->high_mask) {
                        hashp->hdr->low_mask = hashp->hdr->high_mask;
                        hashp->hdr->high_mask =
                            hashp->hdr->max_bucket | hashp->hdr->low_mask;
                }
                change = 1;
        } else if (cmp_n == 0 && !redo) {
                /* Need to undo the split information. */
                hashp->hdr->max_bucket = argp->bucket;
                hashp->hdr->ovfl_point = argp->ovflpoint;
                hashp->hdr->spares[hashp->hdr->ovfl_point] = argp->spares;
                pow = 1 << __db_log2(hashp->hdr->max_bucket + 1);
                hashp->hdr->high_mask = pow - 1;
                hashp->hdr->low_mask = (pow >> 1) - 1;
                change = 1;
        }
        if (change) {
                hashp->hdr->lsn = redo ? *lsnp : argp->metalsn;
                F_SET(file_dbp, DB_HS_DIRTYMETA);
        }
        *lsnp = argp->prev_lsn;

out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;
}

/*
 * __ham_splitdata_recover --
 *
 * PUBLIC: int __ham_splitdata_recover
 * PUBLIC:    __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_splitdata_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_splitdata_args *argp;
        DB *mdbp, *file_dbp;
        DB_MPOOLFILE *mpf;
        HTAB *hashp;
        PAGE *pagep;
        int change, cmp_n, cmp_p, getmeta, ret;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_splitdata_print);
        REC_INTRO(__ham_splitdata_read);

        ret = memp_fget(mpf, &argp->pgno, 0, &pagep);
        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        *lsnp = argp->prev_lsn;
                        ret = 0;
                        goto out;
                } else if ((ret = memp_fget(mpf, &argp->pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;

        cmp_n = log_compare(lsnp, &LSN(pagep));
        cmp_p = log_compare(&LSN(pagep), &argp->pagelsn);

        /*
         * There are two types of log messages here, one for the old page
         * and one for the new pages created.  The original image in the
         * SPLITOLD record is used for undo.  The image in the SPLITNEW
         * is used for redo.  We should never have a case where there is
         * a redo operation and the SPLITOLD record is on disk, but not
         * the SPLITNEW record.  Therefore, we only have work to do when
         * redo NEW messages and undo OLD messages, but we have to update
         * LSNs in both cases.
         */
        change = 0;
        if (cmp_p == 0 && redo) {
                if (argp->opcode == SPLITNEW)
                        /* Need to redo the split described. */
                        memcpy(pagep, argp->pageimage.data,
                            argp->pageimage.size);
                LSN(pagep) = *lsnp;
                change = 1;
        } else if (cmp_n == 0 && !redo) {
                if (argp->opcode == SPLITOLD) {
                        /* Put back the old image. */
                        memcpy(pagep, argp->pageimage.data,
                            argp->pageimage.size);
                } else
                        P_INIT(pagep, file_dbp->pgsize, argp->pgno,
                            PGNO_INVALID, PGNO_INVALID, 0, P_HASH);
                LSN(pagep) = argp->pagelsn;
                change = 1;
        }
        if ((ret = __ham_put_page(file_dbp, pagep, change)) != 0)
                goto out;

        *lsnp = argp->prev_lsn;

out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;
}

/*
 * __ham_ovfl_recover --
 *      This message is generated when we initialize a set of overflow pages.
 *
 * PUBLIC: int __ham_ovfl_recover
 * PUBLIC:     __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_ovfl_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_ovfl_args *argp;
        DB *mdbp, *file_dbp;
        DB_MPOOLFILE *mpf;
        HTAB *hashp;
        PAGE *pagep;
        db_pgno_t max_pgno, pgno;
        int cmp_n, cmp_p, getmeta, ret;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_ovfl_print);
        REC_INTRO(__ham_ovfl_read);

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;

        cmp_n = log_compare(lsnp, &hashp->hdr->lsn);
        cmp_p = log_compare(&hashp->hdr->lsn, &argp->metalsn);

        if (cmp_p == 0 && redo) {
                /* Redo the allocation. */
                hashp->hdr->last_freed = argp->start_pgno;
                hashp->hdr->spares[argp->ovflpoint] += argp->npages;
                hashp->hdr->lsn = *lsnp;
                F_SET(file_dbp, DB_HS_DIRTYMETA);
        } else if (cmp_n == 0 && !redo) {
                hashp->hdr->last_freed = argp->free_pgno;
                hashp->hdr->spares[argp->ovflpoint] -= argp->npages;
                hashp->hdr->lsn = argp->metalsn;
                F_SET(file_dbp, DB_HS_DIRTYMETA);
        }

        max_pgno = argp->start_pgno + argp->npages - 1;
        ret = 0;
        for (pgno = argp->start_pgno; pgno <= max_pgno; pgno++) {
                ret = memp_fget(mpf, &pgno, 0, &pagep);
                if (ret != 0) {
                        if (redo && (ret = memp_fget(mpf, &pgno,
                            DB_MPOOL_CREATE, &pagep)) != 0)
                                goto out;
                        else if (!redo) {
                                (void)__ham_put_page(file_dbp, pagep, 0);
                                continue;
                        }
                }
                if (redo && log_compare((const DB_LSN *)lsnp,
                    (const DB_LSN *)&LSN(pagep)) > 0) {
                        P_INIT(pagep, file_dbp->pgsize, pgno, PGNO_INVALID,
                            pgno == max_pgno ? argp->free_pgno : pgno + 1,
                            0, P_HASH);
                        LSN(pagep) = *lsnp;
                        ret = __ham_put_page(file_dbp, pagep, 1);
                } else if (!redo) {
                        ZERO_LSN(pagep->lsn);
                        ret = __ham_put_page(file_dbp, pagep, 1);
                } else
                        ret = __ham_put_page(file_dbp, pagep, 0);
                if (ret)
                        goto out;
        }

        *lsnp = argp->prev_lsn;
out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;
}

/*
 * __ham_copypage_recover --
 *      Recovery function for copypage.
 *
 * PUBLIC: int __ham_copypage_recover
 * PUBLIC:   __P((DB_LOG *, DBT *, DB_LSN *, int, void *));
 */
int
__ham_copypage_recover(logp, dbtp, lsnp, redo, info)
        DB_LOG *logp;
        DBT *dbtp;
        DB_LSN *lsnp;
        int redo;
        void *info;
{
        __ham_copypage_args *argp;
        DB *file_dbp, *mdbp;
        DB_MPOOLFILE *mpf;
        HTAB *hashp;
        PAGE *pagep;
        int cmp_n, cmp_p, getmeta, modified, ret;

        getmeta = 0;
        hashp = NULL;                           /* XXX: shut the compiler up. */
        REC_PRINT(__ham_copypage_print);
        REC_INTRO(__ham_copypage_read);

        hashp = (HTAB *)file_dbp->internal;
        GET_META(file_dbp, hashp);
        getmeta = 1;
        modified = 0;

        /* This is the bucket page. */
        ret = memp_fget(mpf, &argp->pgno, 0, &pagep);
        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        ret = 0;
                        goto donext;
                } else if ((ret = memp_fget(mpf, &argp->pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        cmp_n = log_compare(lsnp, &LSN(pagep));
        cmp_p = log_compare(&LSN(pagep), &argp->pagelsn);

        if (cmp_p == 0 && redo) {
                /* Need to redo update described. */
                memcpy(pagep, argp->page.data, argp->page.size);
                LSN(pagep) = *lsnp;
                modified = 1;
        } else if (cmp_n == 0 && !redo) {
                /* Need to undo update described. */
                P_INIT(pagep, hashp->hdr->pagesize, argp->pgno, PGNO_INVALID,
                    argp->next_pgno, 0, P_HASH);
                LSN(pagep) = argp->pagelsn;
                modified = 1;
        }
        if ((ret = memp_fput(mpf, pagep, modified ? DB_MPOOL_DIRTY : 0)) != 0)
                goto out;

        /* Now fix up the "next" page. */
donext: ret = memp_fget(mpf, &argp->next_pgno, 0, &pagep);
        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        ret = 0;
                        goto do_nn;
                } else if ((ret = memp_fget(mpf, &argp->next_pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        /* There is nothing to do in the REDO case; only UNDO. */

        cmp_n = log_compare(lsnp, &LSN(pagep));
        if (cmp_n == 0 && !redo) {
                /* Need to undo update described. */
                memcpy(pagep, argp->page.data, argp->page.size);
                modified = 1;
        }
        if ((ret = memp_fput(mpf, pagep, modified ? DB_MPOOL_DIRTY : 0)) != 0)
                goto out;

        /* Now fix up the next's next page. */
do_nn:  if (argp->nnext_pgno == PGNO_INVALID) {
                *lsnp = argp->prev_lsn;
                goto out;
        }

        ret = memp_fget(mpf, &argp->nnext_pgno, 0, &pagep);
        if (ret != 0) {
                if (!redo) {
                        /*
                         * We are undoing and the page doesn't exist.  That
                         * is equivalent to having a pagelsn of 0, so we
                         * would not have to undo anything.  In this case,
                         * don't bother creating a page.
                         */
                        ret = 0;
                        *lsnp = argp->prev_lsn;
                        goto out;
                } else if ((ret = memp_fget(mpf, &argp->nnext_pgno,
                    DB_MPOOL_CREATE, &pagep)) != 0)
                        goto out;
        }

        cmp_n = log_compare(lsnp, &LSN(pagep));
        cmp_p = log_compare(&LSN(pagep), &argp->nnextlsn);

        if (cmp_p == 0 && redo) {
                /* Need to redo update described. */
                PREV_PGNO(pagep) = argp->pgno;
                LSN(pagep) = *lsnp;
                modified = 1;
        } else if (cmp_n == 0 && !redo) {
                /* Need to undo update described. */
                PREV_PGNO(pagep) = argp->next_pgno;
                LSN(pagep) = argp->nnextlsn;
                modified = 1;
        }
        if ((ret = memp_fput(mpf, pagep, modified ? DB_MPOOL_DIRTY : 0)) != 0)
                goto out;

        *lsnp = argp->prev_lsn;

out:    if (getmeta)
                RELEASE_META(file_dbp, hashp);
        REC_CLOSE;
}