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bt_open.c

/*-
 * 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 "db_config.h"

#ifndef lint
static const char revid[] = "$Id: bt_open.c,v 11.42 2000/11/30 00:58:28 ubell Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.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"

/*
 * __bam_open --
 *    Open a btree.
 *
 * PUBLIC: int __bam_open __P((DB *, const char *, db_pgno_t, u_int32_t));
 */
int
__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 = __bam_delete;
      dbp->key_range = __bam_key_range;
      dbp->stat = __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 == __bam_defcmp && t->bt_prefix != __bam_defpfx) {
            __db_err(dbp->dbenv,
"prefix comparison may not be specified for default comparison routine");
            return (EINVAL);
      }

      /*
       * Verify that the bt_minkey value specified won't cause the
       * calculation of ovflsize to underflow [#2406] for this pagesize.
       */
      if (B_MINKEY_TO_OVFLSIZE(t->bt_minkey, dbp->pgsize) >
          B_MINKEY_TO_OVFLSIZE(DEFMINKEYPAGE, dbp->pgsize)) {
            __db_err(dbp->dbenv,
                "bt_minkey value of %lu too high for page size of %lu",
                (u_long)t->bt_minkey, (u_long)dbp->pgsize);
            return (EINVAL);
      }

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

/*
 * __bam_metachk --
 *
 * PUBLIC: int __bam_metachk __P((DB *, const char *, BTMETA *));
 */
int
__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:
            __db_err(dbenv,
                "%s: btree version %lu requires a version upgrade",
                name, (u_long)vers);
            return (DB_OLD_VERSION);
      case 8:
            break;
      default:
            __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 = __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 =
          __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)) {
                  __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 = __db_fcchk(dbenv,
                "DB->open", dbp->flags, DB_AM_DUP, DB_BT_RECNUM)) != 0)
                  return (ret);
      } else
            if (F_ISSET(dbp, DB_BT_RECNUM)) {
                  __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)) {
                  __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)) {
                  __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)) {
                  __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 = __bam_defcmp;
            F_SET(dbp, DB_AM_DUPSORT);
      } else
            if (dbp->dup_compare != NULL) {
                  __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)
            __db_err(dbenv,
                "open method type is Btree, database type is Recno");
      else
            __db_err(dbenv,
                "open method type is Recno, database type is Btree");
      return (EINVAL);
}

/*
 * __bam_read_root --
 *    Check (and optionally create) a tree.
 *
 * PUBLIC: int __bam_read_root __P((DB *, const char *, db_pgno_t, u_int32_t));
 */
int
__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) && CDB_LOCKING(dbp->dbenv) ?
          DB_WRITECURSOR : 0)) != 0)
            return (ret);

      /* Get, and optionally create the metadata page. */
      if ((ret =
          __db_lget(dbc, 0, base_pgno, DB_LOCK_READ, 0, &metalock)) != 0)
            goto err;
      if ((ret = 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)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 (CDB_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 = 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 = __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 = __db_log_page(dbp,
          name, &orig_lsn, base_pgno, (PAGE *)meta)) != 0)
            goto err;

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

      if (dbp->open_txn != NULL && (ret = __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 = __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 = memp_fput(dbp->mpf, meta, DB_MPOOL_DIRTY)) != 0)
            goto err;
      meta = NULL;
      if ((ret = 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 = memp_fsync(dbp->mpf)) == DB_INCOMPLETE) {
            __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 = memp_fput(dbp->mpf, meta, 0)) != 0 &&
                ret == 0)
                  ret = t_ret;
      if (root != NULL)
            if ((t_ret = memp_fput(dbp->mpf, root, 0)) != 0 &&
                ret == 0)
                  ret = t_ret;

      /* We can release the metapage lock when we are done. */
      if ((t_ret = __LPUT(dbc, metalock)) != 0 && ret == 0)
            ret = t_ret;

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

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