db_dispatch.c

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/*-
 * 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 "config.h"

#ifndef lint
static const char revid[] = "$Id: db__dispatch_8c-source.html,v 1.1 2008/06/08 10:17:25 sebdiaz 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"

/*
 * CDB___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 CDB___db_dispatch __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
 */
int
CDB___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;

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

        switch (redo) {
        case DB_TXN_ABORT:
                return ((dbenv->dtab[rectype])(dbenv, db, lsnp, redo, info));
        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.  If we've never
                 * seen it, then we call the appropriate recovery routine
                 * in "abort mode".
                 *
                 * 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 ||
                    (CDB___db_txnlist_find(info, txnid) == DB_NOTFOUND &&
                    txnid != 0))
                        return (dbenv->dtab[rectype](dbenv,
                            db, lsnp, DB_TXN_BACKWARD_ROLL, info));
                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 ||
                    CDB___db_txnlist_find(info, txnid) != DB_NOTFOUND)
                        return (dbenv->dtab[rectype](dbenv,
                            db, lsnp, DB_TXN_FORWARD_ROLL, info));
                break;
        default:
                return (CDB___db_unknown_flag(dbenv, "CDB___db_dispatch", redo));
        }
        return (0);
}

/*
 * CDB___db_add_recovery --
 *
 * PUBLIC: int CDB___db_add_recovery __P((DB_ENV *,
 * PUBLIC:    int (*)(DB_ENV *, DBT *, DB_LSN *, db_recops, void *), u_int32_t));
 */
int
CDB___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 = CDB___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);
}

/*
 * CDB___deprecated_recover --
 *      Stub routine for deprecated recovery functions.
 *
 * PUBLIC: int CDB___deprecated_recover
 * PUBLIC:     __P((DB_ENV *, DBT *, DB_LSN *, db_recops, void *));
 */
int
CDB___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);
}

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

        if ((ret = CDB___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);
}

/*
 * CDB___db_txnlist_add --
 *      Add an element to our transaction linked list.
 *
 * PUBLIC: int CDB___db_txnlist_add __P((DB_ENV *, void *, u_int32_t));
 */
int
CDB___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 = CDB___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);
}

/* CDB___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 CDB___db_txnlist_close __P((void *, int32_t, u_int32_t));
 */

int
CDB___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);
}

/*
 * CDB___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 CDB___db_txnlist_delete __P((DB_ENV *,
 * PUBLIC:     void *, char *, u_int32_t, int));
 */
int
CDB___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 = CDB___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 = CDB___os_strdup(dbenv, name, &p->u.d.fname);

        return (ret);
}

/*
 * CDB___db_txnlist_end --
 *      Discard transaction linked list. Print out any error messages
 * for deleted files.
 *
 * PUBLIC: void CDB___db_txnlist_end __P((DB_ENV *, void *));
 */
void
CDB___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);
                if (p->type == 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))
                                CDB___db_err(dbenv, "warning: %s: %s",
                                    p->u.d.fname, CDB_db_strerror(ENOENT));
                        CDB___os_freestr(p->u.d.fname);
                }
                CDB___os_free(p, sizeof(DB_TXNLIST));
        }
        CDB___os_free(listp, sizeof(DB_TXNHEAD));
}

/*
 * CDB___db_txnlist_find --
 *      Checks to see if a txnid with the current generation is in the
 *      txnid list.
 *
 * PUBLIC: int CDB___db_txnlist_find __P((void *, u_int32_t));
 */
int
CDB___db_txnlist_find(listp, txnid)
        void *listp;
        u_int32_t txnid;
{
        DB_TXNHEAD *hp;
        DB_TXNLIST *p;

        if (txnid == 0 || (hp = (DB_TXNHEAD *)listp) == NULL)
                return (DB_NOTFOUND);

        for (p = LIST_FIRST(&hp->head); p != NULL; p = LIST_NEXT(p, links)) {
                if (p->type != TXNLIST_TXNID)
                        continue;
                if (p->u.t.txnid == txnid &&
                    hp->generation == p->u.t.generation) {
                        /* Move it to head of list. */
                        if (p != LIST_FIRST(&hp->head)) {
                                LIST_REMOVE(p, links);
                                LIST_INSERT_HEAD(&hp->head, p, links);
                        }
                        return (0);
                }
        }

        return (DB_NOTFOUND);
}

/*
 * CDB___db_txnlist_gen --
 *      Change the current generation number.
 *
 * PUBLIC: void CDB___db_txnlist_gen __P((void *, int));
 */
void
CDB___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;
}

#ifdef DEBUG
/*
 * CDB___db_txnlist_print --
 *      Print out the transaction list.
 *
 * PUBLIC: void CDB___db_txnlist_print __P((void *));
 */
void
CDB___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

---