bt_open.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: bt__open_8c-source.html,v 1.1 2008/06/08 10:13:37 sebdiaz Exp $";
#endif /* not lint */

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

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

#include "db_int.h"
#include "db_page.h"
#include "db_swap.h"
#include "btree.h"
#include "db_shash.h"
#include "lock.h"
#include "log.h"
#include "mp.h"

/*
 * CDB___bam_open --
 *      Open a btree.
 *
 * PUBLIC: int CDB___bam_open __P((DB *, const char *, db_pgno_t, u_int32_t));
 */
int
CDB___bam_open(dbp, name, base_pgno, flags)
        DB *dbp;
        const char *name;
        db_pgno_t base_pgno;
        u_int32_t flags;
{
        BTREE *t;

        t = dbp->bt_internal;

        /* Initialize the remaining fields/methods of the DB. */
        dbp->del = CDB___bam_delete;
        dbp->key_range = CDB___bam_key_range;
        dbp->stat = CDB___bam_stat;

        /*
         * We don't permit the user to specify a prefix routine if they didn't
         * also specify a comparison routine, they can't know enough about our
         * comparison routine to get it right.
         */
        if (t->bt_compare == CDB___bam_defcmp && t->bt_prefix != CDB___bam_defpfx) {
                CDB___db_err(dbp->dbenv,
"prefix comparison may not be specified for default comparison routine");
                return (EINVAL);
        }

        /* Start up the tree. */
        return (CDB___bam_read_root(dbp, name, base_pgno, flags));
}

/*
 * CDB___bam_metachk --
 *
 * PUBLIC: int CDB___bam_metachk __P((DB *, const char *, BTMETA *));
 */
int
CDB___bam_metachk(dbp, name, btm)
        DB *dbp;
        const char *name;
        BTMETA *btm;
{
        DB_ENV *dbenv;
        u_int32_t vers;
        int ret;

        dbenv = dbp->dbenv;

        /*
         * At this point, all we know is that the magic number is for a Btree.
         * Check the version, the database may be out of date.
         */
        vers = btm->dbmeta.version;
        if (F_ISSET(dbp, DB_AM_SWAP))
                M_32_SWAP(vers);
        switch (vers) {
        case 6:
        case 7:
                CDB___db_err(dbenv,
                    "%s: btree version %lu requires a version upgrade",
                    name, (u_long)vers);
                return (DB_OLD_VERSION);
        case 8:
                break;
        default:
                CDB___db_err(dbenv,
                    "%s: unsupported btree version: %lu", name, (u_long)vers);
                return (EINVAL);
        }

        /* Swap the page if we need to. */
        if (F_ISSET(dbp, DB_AM_SWAP) && (ret = CDB___bam_mswap((PAGE *)btm)) != 0)
                return (ret);

        /*
         * Check application info against metadata info, and set info, flags,
         * and type based on metadata info.
         */
        if ((ret =
            CDB___db_fchk(dbenv, "DB->open", btm->dbmeta.flags, BTM_MASK)) != 0)
                return (ret);

        if (F_ISSET(&btm->dbmeta, BTM_RECNO)) {
                if (dbp->type == DB_BTREE)
                        goto wrong_type;
                dbp->type = DB_RECNO;
                DB_ILLEGAL_METHOD(dbp, DB_OK_RECNO);
        } else {
                if (dbp->type == DB_RECNO)
                        goto wrong_type;
                dbp->type = DB_BTREE;
                DB_ILLEGAL_METHOD(dbp, DB_OK_BTREE);
        }

        if (F_ISSET(&btm->dbmeta, BTM_DUP))
                F_SET(dbp, DB_AM_DUP);
        else
                if (F_ISSET(dbp, DB_AM_DUP)) {
                        CDB___db_err(dbenv,
                "%s: DB_DUP specified to open method but not set in database",
                            name);
                        return (EINVAL);
                }

        if (F_ISSET(&btm->dbmeta, BTM_RECNUM)) {
                if (dbp->type != DB_BTREE)
                        goto wrong_type;
                F_SET(dbp, DB_BT_RECNUM);

                if ((ret = CDB___db_fcchk(dbenv,
                    "DB->open", dbp->flags, DB_AM_DUP, DB_BT_RECNUM)) != 0)
                        return (ret);
        } else
                if (F_ISSET(dbp, DB_BT_RECNUM)) {
                        CDB___db_err(dbenv,
            "%s: DB_RECNUM specified to open method but not set in database",
                            name);
                        return (EINVAL);
                }

        if (F_ISSET(&btm->dbmeta, BTM_FIXEDLEN)) {
                if (dbp->type != DB_RECNO)
                        goto wrong_type;
                F_SET(dbp, DB_RE_FIXEDLEN);
        } else
                if (F_ISSET(dbp, DB_RE_FIXEDLEN)) {
                        CDB___db_err(dbenv,
        "%s: DB_FIXEDLEN specified to open method but not set in database",
                            name);
                        return (EINVAL);
                }

        if (F_ISSET(&btm->dbmeta, BTM_RENUMBER)) {
                if (dbp->type != DB_RECNO)
                        goto wrong_type;
                F_SET(dbp, DB_RE_RENUMBER);
        } else
                if (F_ISSET(dbp, DB_RE_RENUMBER)) {
                        CDB___db_err(dbenv,
            "%s: DB_RENUMBER specified to open method but not set in database",
                            name);
                        return (EINVAL);
                }

        if (F_ISSET(&btm->dbmeta, BTM_SUBDB))
                F_SET(dbp, DB_AM_SUBDB);
        else
                if (F_ISSET(dbp, DB_AM_SUBDB)) {
                        CDB___db_err(dbenv,
            "%s: multiple databases specified but not supported by file",
                            name);
                        return (EINVAL);
                }

        if (F_ISSET(&btm->dbmeta, BTM_DUPSORT)) {
                if (dbp->dup_compare == NULL)
                        dbp->dup_compare = CDB___bam_defcmp;
                F_SET(dbp, DB_AM_DUPSORT);
        } else
                if (dbp->dup_compare != NULL) {
                        CDB___db_err(dbenv,
                "%s: duplicate sort specified but not supported in database",
                            name);
                        return (EINVAL);
                }

        /* Set the page size. */
        dbp->pgsize = btm->dbmeta.pagesize;

        /* Copy the file's ID. */
        memcpy(dbp->fileid, btm->dbmeta.uid, DB_FILE_ID_LEN);

        return (0);

wrong_type:
        if (dbp->type == DB_BTREE)
                CDB___db_err(dbenv,
                    "open method type is Btree, database type is Recno");
        else
                CDB___db_err(dbenv,
                    "open method type is Recno, database type is Btree");
        return (EINVAL);
}

/*
 * CDB___bam_read_root --
 *      Check (and optionally create) a tree.
 *
 * PUBLIC: int CDB___bam_read_root __P((DB *, const char *, db_pgno_t, u_int32_t));
 */
int
CDB___bam_read_root(dbp, name, base_pgno, flags)
        DB *dbp;
        const char *name;
        db_pgno_t base_pgno;
        u_int32_t flags;
{
        BTMETA *meta;
        BTREE *t;
        DBC *dbc;
        DB_LSN orig_lsn;
        DB_LOCK metalock;
        PAGE *root;
        int locked, ret, t_ret;

        ret = 0;
        t = dbp->bt_internal;
        meta = NULL;
        root = NULL;
        locked = 0;

        /* 
         * Get a cursor.  If DB_CREATE is specified, we may be creating
         * the root page, and to do that safely in CDB we need a write
         * cursor.  In STD_LOCKING mode, we'll synchronize using the 
         * meta page lock instead.
         */
        if ((ret = dbp->cursor(dbp, dbp->open_txn,
            &dbc, LF_ISSET(DB_CREATE) && LOCKING(dbp->dbenv) ? 
            DB_WRITECURSOR : 0)) != 0)
                return (ret);

        /* Get, and optionally create the metadata page. */
        if ((ret =
            CDB___db_lget(dbc, 0, base_pgno, DB_LOCK_READ, 0, &metalock)) != 0)
                goto err;
        if ((ret = CDB_memp_fget(
            dbp->mpf, &base_pgno, DB_MPOOL_CREATE, (PAGE **)&meta)) != 0)
                goto err;

        /*
         * If the magic number is correct, we're not creating the tree.
         * Correct any fields that may not be right.  Note, all of the
         * local flags were set by DB->open.
         */
again:  if (meta->dbmeta.magic != 0) {
                t->bt_maxkey = meta->maxkey;
                t->bt_minkey = meta->minkey;
                t->re_pad = meta->re_pad;
                t->re_len = meta->re_len;

                t->bt_meta = base_pgno;
                t->bt_root = meta->root;

                (void)CDB_memp_fput(dbp->mpf, meta, 0);
                meta = NULL;
                goto done;
        }

        /* In recovery if it's not there it will be created elsewhere.*/
        if (IS_RECOVERING(dbp->dbenv))
                goto done;

        /* If we're doing CDB; we now have to get the write lock. */
        if (LOCKING(dbp->dbenv)) {
                /* 
                 * We'd better have DB_CREATE set if we're actually doing 
                 * the create. 
                 */
                DB_ASSERT(LF_ISSET(DB_CREATE));
                if ((ret = CDB_lock_get(dbp->dbenv, dbc->locker, DB_LOCK_UPGRADE,
                    &dbc->lock_dbt, DB_LOCK_WRITE, &dbc->mylock)) != 0)
                        goto err;
        }

        /*
         * If we are doing locking, relase the read lock and get a write lock.
         * We want to avoid deadlock.
         */
        if (locked == 0 && STD_LOCKING(dbc)) {
                if ((ret = __LPUT(dbc, metalock)) != 0)
                        goto err;
                if ((ret = CDB___db_lget(dbc,
                     0, base_pgno, DB_LOCK_WRITE, 0, &metalock)) != 0)
                        goto err;
                locked = 1;
                goto again;
        }

        /* Initialize the tree structure metadata information. */
        orig_lsn = meta->dbmeta.lsn;
        memset(meta, 0, sizeof(BTMETA));
        meta->dbmeta.lsn = orig_lsn;
        meta->dbmeta.pgno = base_pgno;
        meta->dbmeta.magic = DB_BTREEMAGIC;
        meta->dbmeta.version = DB_BTREEVERSION;
        meta->dbmeta.pagesize = dbp->pgsize;
        meta->dbmeta.type = P_BTREEMETA;
        meta->dbmeta.free = PGNO_INVALID;
        if (F_ISSET(dbp, DB_AM_DUP))
                F_SET(&meta->dbmeta, BTM_DUP);
        if (F_ISSET(dbp, DB_RE_FIXEDLEN))
                F_SET(&meta->dbmeta, BTM_FIXEDLEN);
        if (F_ISSET(dbp, DB_BT_RECNUM))
                F_SET(&meta->dbmeta, BTM_RECNUM);
        if (F_ISSET(dbp, DB_RE_RENUMBER))
                F_SET(&meta->dbmeta, BTM_RENUMBER);
        if (F_ISSET(dbp, DB_AM_SUBDB))
                F_SET(&meta->dbmeta, BTM_SUBDB);
        if (dbp->dup_compare != NULL)
                F_SET(&meta->dbmeta, BTM_DUPSORT);
        if (dbp->type == DB_RECNO)
                F_SET(&meta->dbmeta, BTM_RECNO);
        memcpy(meta->dbmeta.uid, dbp->fileid, DB_FILE_ID_LEN);

        meta->maxkey = t->bt_maxkey;
        meta->minkey = t->bt_minkey;
        meta->re_len = t->re_len;
        meta->re_pad = t->re_pad;

        /* If necessary, log the meta-data and root page creates.  */
        if ((ret = CDB___db_log_page(dbp,
            name, &orig_lsn, base_pgno, (PAGE *)meta)) != 0)
                goto err;

        /* Create and initialize a root page. */
        if ((ret = CDB___db_new(dbc,
            ((dbp->type == DB_RECNO ? P_LRECNO : P_LBTREE) | dbp->tags), &root)) != 0)
                goto err;
        root->level = LEAFLEVEL;

        if (dbp->open_txn != NULL && (ret = CDB___bam_root_log(dbp->dbenv,
            dbp->open_txn, &meta->dbmeta.lsn, 0, dbp->log_fileid,
            meta->dbmeta.pgno, root->pgno, &meta->dbmeta.lsn)) != 0)
                goto err;

        meta->root = root->pgno;

        DB_TEST_RECOVERY(dbp, DB_TEST_POSTLOGMETA, ret, name);
        if ((ret = CDB___db_log_page(dbp,
            name, &root->lsn, root->pgno, root)) != 0)
                goto err;
        DB_TEST_RECOVERY(dbp, DB_TEST_POSTLOG, ret, name);

        t->bt_meta = base_pgno;
        t->bt_root = root->pgno;

        /* Release the metadata and root pages. */
        if ((ret = CDB_memp_fput(dbp->mpf, meta, DB_MPOOL_DIRTY)) != 0)
                goto err;
        meta = NULL;
        if ((ret = CDB_memp_fput(dbp->mpf, root, DB_MPOOL_DIRTY)) != 0)
                goto err;
        root = NULL;

        /*
         * Flush the metadata and root pages to disk.
         *
         * !!!
         * It's not useful to return not-yet-flushed here -- convert it to
         * an error.
         */
        if ((ret = CDB_memp_fsync(dbp->mpf)) == DB_INCOMPLETE) {
                CDB___db_err(dbp->dbenv, "Metapage flush failed");
                ret = EINVAL;
        }
        DB_TEST_RECOVERY(dbp, DB_TEST_POSTSYNC, ret, name);

done:   /*
         * !!!
         * We already did an insert and so the last-page-inserted has been
         * set.  I'm not sure where the *right* place to clear this value
         * is, it's not intuitively obvious that it belongs here.
         */
        t->bt_lpgno = PGNO_INVALID;

err:
DB_TEST_RECOVERY_LABEL
        /* Put any remaining pages back. */
        if (meta != NULL)
                if ((t_ret = CDB_memp_fput(dbp->mpf, meta, 0)) != 0 &&
                    ret == 0)
                        ret = t_ret;
        if (root != NULL)
                if ((t_ret = CDB_memp_fput(dbp->mpf, root, 0)) != 0 &&
                    ret == 0)
                        ret = t_ret;

        /* We can release the metapage lock when we are done. */
        (void)__LPUT(dbc, metalock);

        if ((t_ret = dbc->c_close(dbc)) != 0 && ret == 0)
                ret = t_ret;
        return (ret);
}

---