db_meta.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) 1990, 1993, 1994, 1995, 1996
 *      Keith Bostic.  All rights reserved.
 */
/*
 * Copyright (c) 1990, 1993, 1994, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Olson.
 *
 * 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__meta_8c-source.html,v 1.1 2008/06/08 10:17:51 sebdiaz Exp $";
#endif /* not lint */

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

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

#include "db_int.h"
#include "db_page.h"
#include "db_shash.h"
#include "lock.h"
#include "txn.h"
#include "db_am.h"
#include "btree.h"

/*
 * CDB___db_new --
 *      Get a new page, preferably from the freelist.
 *
 * PUBLIC: int CDB___db_new __P((DBC *, u_int32_t, PAGE **));
 */
int
CDB___db_new(dbc, type, pagepp)
        DBC *dbc;
        u_int32_t type;
        PAGE **pagepp;
{
        DBMETA *meta;
        DB *dbp;
        DB_LOCK metalock;
        PAGE *h;
        db_pgno_t pgno;
        int ret;

        dbp = dbc->dbp;
        meta = NULL;
        h = NULL;

        pgno = PGNO_BASE_MD;
        if ((ret = CDB___db_lget(dbc,
            LCK_ALWAYS, pgno, DB_LOCK_WRITE, 0, &metalock)) != 0)
                goto err;
        if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, (PAGE **)&meta)) != 0)
                goto err;

        if (meta->free == PGNO_INVALID) {
                if ((ret = CDB_memp_fget(dbp->mpf, &pgno, DB_MPOOL_NEW, &h)) != 0)
                        goto err;
                ZERO_LSN(h->lsn);
                h->pgno = pgno;
        } else {
                pgno = meta->free;
                if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, &h)) != 0)
                        goto err;
                meta->free = h->next_pgno;
                (void)CDB_memp_fset(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
        }

        /* Log the change. */
        if (DB_LOGGING(dbc)) {
                if ((ret = __db_pg_alloc_log(dbp->dbenv,
                    dbc->txn, &LSN(meta), 0, dbp->log_fileid,
                    &LSN(meta), &meta->alloc_lsn, &h->lsn, h->pgno,
                    (u_int32_t)type, meta->free)) != 0)
                        goto err;
                LSN(h) = LSN(meta);
                meta->alloc_lsn = LSN(meta);
        }

        (void)CDB_memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
        (void)__TLPUT(dbc, metalock);

        P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, PGNO_INVALID, 0, type, 0);
        *pagepp = h;
        return (0);

err:    if (h != NULL)
                (void)CDB_memp_fput(dbp->mpf, h, 0);
        if (meta != NULL)
                (void)CDB_memp_fput(dbp->mpf, meta, 0);
        (void)__TLPUT(dbc, metalock);
        return (ret);
}

/*
 * CDB___db_free --
 *      Add a page to the head of the freelist.
 *
 * PUBLIC: int CDB___db_free __P((DBC *, PAGE *));
 */
int
CDB___db_free(dbc, h)
        DBC *dbc;
        PAGE *h;
{
        DBMETA *meta;
        DB *dbp;
        DBT ldbt;
        DB_LOCK metalock;
        db_pgno_t pgno;
        u_int32_t dirty_flag;
        int ret, t_ret;

        dbp = dbc->dbp;

        /*
         * Retrieve the metadata page and insert the page at the head of
         * the free list.  If either the lock get or page get routines
         * fail, then we need to put the page with which we were called
         * back because our caller assumes we take care of it.
         */
        dirty_flag = 0;
        pgno = PGNO_BASE_MD;
        if ((ret = CDB___db_lget(dbc,
             LCK_ALWAYS, pgno, DB_LOCK_WRITE, 0, &metalock)) != 0)
                goto err;
        if ((ret = CDB_memp_fget(dbp->mpf, &pgno, 0, (PAGE **)&meta)) != 0) {
                (void)__TLPUT(dbc, metalock);
                goto err;
        }

        /* Log the change. */
        if (DB_LOGGING(dbc)) {
                memset(&ldbt, 0, sizeof(ldbt));
                ldbt.data = h;
                ldbt.size = P_OVERHEAD;
                if ((ret = __db_pg_free_log(dbp->dbenv,
                    dbc->txn, &LSN(meta), 0, dbp->log_fileid, h->pgno,
                    &LSN(meta), &meta->alloc_lsn, &ldbt, meta->free)) != 0) {
                        (void)CDB_memp_fput(dbp->mpf, (PAGE *)meta, 0);
                        (void)__TLPUT(dbc, metalock);
                        return (ret);
                }
                LSN(h) = LSN(meta);
                meta->alloc_lsn = LSN(meta);
        }

        P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, meta->free, 0, P_INVALID, 0);

        /* Link the page on the metadata free list. */
        meta->free = h->pgno;

        /* Discard the metadata page. */
        ret = CDB_memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
        if ((t_ret = __TLPUT(dbc, metalock)) != 0)
                ret = t_ret;

        /* Discard the caller's page reference. */
        dirty_flag = DB_MPOOL_DIRTY;
err:    if ((t_ret = CDB_memp_fput(dbp->mpf, h, dirty_flag)) != 0 && ret == 0)
                ret = t_ret;

        /*
         * XXX
         * We have to unlock the caller's page in the caller!
         */
        return (ret);
}

#ifdef DEBUG
/*
 * CDB___db_lprint --
 *      Print out the list of locks currently held by a cursor.
 *
 * PUBLIC: int CDB___db_lprint __P((DBC *));
 */
int
CDB___db_lprint(dbc)
        DBC *dbc;
{
        DB *dbp;
        DB_LOCKREQ req;

        dbp = dbc->dbp;

        if (LOCKING_ON(dbp->dbenv)) {
                req.op = DB_LOCK_DUMP;
                CDB_lock_vec(dbp->dbenv, dbc->locker, 0, &req, 1, NULL);
        }
        return (0);
}
#endif

/*
 * CDB___db_lget --
 *      The standard lock get call.
 *
 * PUBLIC: int CDB___db_lget __P((DBC *,
 * PUBLIC:     int, db_pgno_t, db_lockmode_t, int, DB_LOCK *));
 */
int
CDB___db_lget(dbc, flags, pgno, mode, lkflags, lockp)
        DBC *dbc;
        int flags, lkflags;
        db_pgno_t pgno;
        db_lockmode_t mode;
        DB_LOCK *lockp;
{
        DB *dbp;
        DB_ENV *dbenv;
        DB_LOCKREQ couple[2];
        int ret;

        dbp = dbc->dbp;
        dbenv = dbp->dbenv;

        /*
         * We do not always check if we're configured for locking before
         * calling CDB___db_lget to acquire the lock.
         */
        if (LOCKING(dbenv) || !LOCKING_ON(dbenv)
            || (!LF_ISSET(LCK_ROLLBACK) && F_ISSET(dbc, DBC_RECOVER))
            || (!LF_ISSET(LCK_ALWAYS) && F_ISSET(dbc, DBC_OPD))) {
                lockp->off = LOCK_INVALID;
                return (0);
        }

        dbc->lock.pgno = pgno;
        if (lkflags & DB_LOCK_RECORD)
                dbc->lock.type = DB_RECORD_LOCK;
        else
                dbc->lock.type = DB_PAGE_LOCK;
        lkflags &= ~DB_LOCK_RECORD;

        /*
         * If the transaction enclosing this cursor has DB_LOCK_NOWAIT set,
         * pass that along to the lock call.
         */
        if (DB_NONBLOCK(dbc))
                lkflags |= DB_LOCK_NOWAIT;

        /*
         * If the object not currently locked, acquire the lock and return,
         * otherwise, lock couple.
         */
        if (LF_ISSET(LCK_COUPLE)) {
                couple[0].op = DB_LOCK_GET;
                couple[0].obj = &dbc->lock_dbt;
                couple[0].mode = mode;
                couple[1].op = DB_LOCK_PUT;
                couple[1].lock = *lockp;

                if ((ret = CDB_lock_vec(dbenv,
                    dbc->locker, lkflags, couple, 2, NULL)) == 0)
                        *lockp = couple[0].lock;
        } else
                ret = CDB_lock_get(dbenv,
                    dbc->locker, lkflags, &dbc->lock_dbt, mode, lockp);

        if (ret != 0)
                lockp->off = LOCK_INVALID;

        return (ret);
}

---