hash_open.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2005
 *      Sleepycat Software.  All rights reserved.
 */
/*
 * Copyright (c) 1990, 1993, 1994
 *      Margo Seltzer.  All rights reserved.
 */
/*
 * Copyright (c) 1990, 1993, 1994
 *      The Regents of the University of California.  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.
 *
 * $Id: hash_open.c,v 12.7 2005/11/09 14:19:51 margo Exp $
 */

#include "db_config.h"

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

#include <string.h>
#endif

#include "db_int.h"
#include "dbinc/crypto.h"
#include "dbinc/db_page.h"
#include "dbinc/hash.h"
#include "dbinc/log.h"
#include "dbinc/db_shash.h"
#include "dbinc/lock.h"
#include "dbinc/mp.h"
#include "dbinc/btree.h"
#include "dbinc/fop.h"

static db_pgno_t __ham_init_meta __P((DB *, HMETA *, db_pgno_t, DB_LSN *));

/*
 * __ham_open --
 *
 * PUBLIC: int __ham_open __P((DB *,
 * PUBLIC:     DB_TXN *, const char * name, db_pgno_t, u_int32_t));
 */
int
__ham_open(dbp, txn, name, base_pgno, flags)
        DB *dbp;
        DB_TXN *txn;
        const char *name;
        db_pgno_t base_pgno;
        u_int32_t flags;
{
        DB_ENV *dbenv;
        DBC *dbc;
        HASH_CURSOR *hcp;
        HASH *hashp;
        int ret, t_ret;

        dbenv = dbp->dbenv;
        dbc = NULL;

        /*
         * Get a cursor.  If DB_CREATE is specified, we may be creating
         * pages, 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 = __db_cursor(dbp,
            txn, &dbc, LF_ISSET(DB_CREATE) && CDB_LOCKING(dbenv) ?
            DB_WRITECURSOR : 0)) != 0)
                return (ret);

        hcp = (HASH_CURSOR *)dbc->internal;
        hashp = dbp->h_internal;
        hashp->meta_pgno = base_pgno;
        if ((ret = __ham_get_meta(dbc)) != 0)
                goto err1;

        /* Initialize the hdr structure.  */
        if (hcp->hdr->dbmeta.magic == DB_HASHMAGIC) {
                /* File exists, verify the data in the header. */
                if (hashp->h_hash == NULL)
                        hashp->h_hash = hcp->hdr->dbmeta.version < 5
                        ? __ham_func4 : __ham_func5;
                if (!F_ISSET(dbp, DB_AM_RDONLY) && !IS_RECOVERING(dbenv) &&
                    hashp->h_hash(dbp,
                    CHARKEY, sizeof(CHARKEY)) != hcp->hdr->h_charkey) {
                        __db_err(dbp->dbenv,
                            "hash: incompatible hash function");
                        ret = EINVAL;
                        goto err2;
                }
                hashp->h_nelem = hcp->hdr->nelem;
                if (F_ISSET(&hcp->hdr->dbmeta, DB_HASH_DUP))
                        F_SET(dbp, DB_AM_DUP);
                if (F_ISSET(&hcp->hdr->dbmeta, DB_HASH_DUPSORT))
                        F_SET(dbp, DB_AM_DUPSORT);
                if (F_ISSET(&hcp->hdr->dbmeta, DB_HASH_SUBDB))
                        F_SET(dbp, DB_AM_SUBDB);

        } else if (!IS_RECOVERING(dbenv) && !F_ISSET(dbp, DB_AM_RECOVER)) {
                __db_err(dbp->dbenv,
                    "%s: Invalid hash meta page %d", name, base_pgno);
                ret = EINVAL;
        }

err2:   /* Release the meta data page */
        if ((t_ret = __ham_release_meta(dbc)) != 0 && ret == 0)
                ret = t_ret;
err1:   if ((t_ret  = __db_c_close(dbc)) != 0 && ret == 0)
                ret = t_ret;

        return (ret);
}

/*
 * __ham_metachk --
 *
 * PUBLIC: int __ham_metachk __P((DB *, const char *, HMETA *));
 */
int
__ham_metachk(dbp, name, hashm)
        DB *dbp;
        const char *name;
        HMETA *hashm;
{
        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 Hash.
         * Check the version, the database may be out of date.
         */
        vers = hashm->dbmeta.version;
        if (F_ISSET(dbp, DB_AM_SWAP))
                M_32_SWAP(vers);
        switch (vers) {
        case 4:
        case 5:
        case 6:
                __db_err(dbenv,
                    "%s: hash version %lu requires a version upgrade",
                    name, (u_long)vers);
                return (DB_OLD_VERSION);
        case 7:
        case 8:
                break;
        default:
                __db_err(dbenv,
                    "%s: unsupported hash version: %lu", name, (u_long)vers);
                return (EINVAL);
        }

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

        /* Check the type. */
        if (dbp->type != DB_HASH && dbp->type != DB_UNKNOWN)
                return (EINVAL);
        dbp->type = DB_HASH;
        DB_ILLEGAL_METHOD(dbp, DB_OK_HASH);

        /*
         * Check application info against metadata info, and set info, flags,
         * and type based on metadata info.
         */
        if ((ret = __db_fchk(dbenv,
            "DB->open", hashm->dbmeta.flags,
            DB_HASH_DUP | DB_HASH_SUBDB | DB_HASH_DUPSORT)) != 0)
                return (ret);

        if (F_ISSET(&hashm->dbmeta, DB_HASH_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(&hashm->dbmeta, DB_HASH_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 in file",
                        name);
                        return (EINVAL);
                }

        if (F_ISSET(&hashm->dbmeta, DB_HASH_DUPSORT)) {
                if (dbp->dup_compare == NULL)
                        dbp->dup_compare = __bam_defcmp;
        } else
                if (dbp->dup_compare != NULL) {
                        __db_err(dbenv,
                "%s: duplicate sort function specified but not set in database",
                            name);
                        return (EINVAL);
                }

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

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

        return (0);
}

/*
 * __ham_init_meta --
 *
 * Initialize a hash meta-data page.  We assume that the meta-data page is
 * contiguous with the initial buckets that we create.  If that turns out
 * to be false, we'll fix it up later.  Return the initial number of buckets
 * allocated.
 */
static db_pgno_t
__ham_init_meta(dbp, meta, pgno, lsnp)
        DB *dbp;
        HMETA *meta;
        db_pgno_t pgno;
        DB_LSN *lsnp;
{
        HASH *hashp;
        db_pgno_t nbuckets;
        u_int i, l2;

        hashp = dbp->h_internal;
        if (hashp->h_hash == NULL)
                hashp->h_hash = DB_HASHVERSION < 5 ? __ham_func4 : __ham_func5;

        if (hashp->h_nelem != 0 && hashp->h_ffactor != 0) {
                hashp->h_nelem = (hashp->h_nelem - 1) / hashp->h_ffactor + 1;
                l2 = __db_log2(hashp->h_nelem > 2 ? hashp->h_nelem : 2);
        } else
                l2 = 1;
        nbuckets = (db_pgno_t)(1 << l2);

        memset(meta, 0, sizeof(HMETA));
        meta->dbmeta.lsn = *lsnp;
        meta->dbmeta.pgno = pgno;
        meta->dbmeta.magic = DB_HASHMAGIC;
        meta->dbmeta.version = DB_HASHVERSION;
        meta->dbmeta.pagesize = dbp->pgsize;
        if (F_ISSET(dbp, DB_AM_CHKSUM))
                FLD_SET(meta->dbmeta.metaflags, DBMETA_CHKSUM);
        if (F_ISSET(dbp, DB_AM_ENCRYPT)) {
                meta->dbmeta.encrypt_alg =
                   ((DB_CIPHER *)dbp->dbenv->crypto_handle)->alg;
                DB_ASSERT(meta->dbmeta.encrypt_alg != 0);
                meta->crypto_magic = meta->dbmeta.magic;
        }
        meta->dbmeta.type = P_HASHMETA;
        meta->dbmeta.free = PGNO_INVALID;
        meta->dbmeta.last_pgno = pgno;
        meta->max_bucket = nbuckets - 1;
        meta->high_mask = nbuckets - 1;
        meta->low_mask = (nbuckets >> 1) - 1;
        meta->ffactor = hashp->h_ffactor;
        meta->nelem = hashp->h_nelem;
        meta->h_charkey = hashp->h_hash(dbp, CHARKEY, sizeof(CHARKEY));
        memcpy(meta->dbmeta.uid, dbp->fileid, DB_FILE_ID_LEN);

        if (F_ISSET(dbp, DB_AM_DUP))
                F_SET(&meta->dbmeta, DB_HASH_DUP);
        if (F_ISSET(dbp, DB_AM_SUBDB))
                F_SET(&meta->dbmeta, DB_HASH_SUBDB);
        if (dbp->dup_compare != NULL)
                F_SET(&meta->dbmeta, DB_HASH_DUPSORT);

        /*
         * Create the first and second buckets pages so that we have the
         * page numbers for them and we can store that page number in the
         * meta-data header (spares[0]).
         */
        meta->spares[0] = pgno + 1;

        /* Fill in the last fields of the meta data page. */
        for (i = 1; i <= l2; i++)
                meta->spares[i] = meta->spares[0];
        for (; i < NCACHED; i++)
                meta->spares[i] = PGNO_INVALID;

        return (nbuckets);
}

/*
 * __ham_new_file --
 *      Create the necessary pages to begin a new database file.  If name
 * is NULL, then this is an unnamed file, the mpf has been set in the dbp
 * and we simply create the pages using mpool.  In this case, we don't log
 * because we never have to redo an unnamed create and the undo simply
 * frees resources.
 *
 * This code appears more complex than it is because of the two cases (named
 * and unnamed).  The way to read the code is that for each page being created,
 * there are three parts: 1) a "get page" chunk (which either uses malloc'd
 * memory or calls __memp_fget), 2) the initialization, and 3) the "put page"
 * chunk which either does a fop write or an __memp_fput.
 *
 * PUBLIC: int __ham_new_file __P((DB *, DB_TXN *, DB_FH *, const char *));
 */
int
__ham_new_file(dbp, txn, fhp, name)
        DB *dbp;
        DB_TXN *txn;
        DB_FH *fhp;
        const char *name;
{
        DB_ENV *dbenv;
        DB_LSN lsn;
        DB_MPOOLFILE *mpf;
        DB_PGINFO pginfo;
        DBT pdbt;
        HMETA *meta;
        PAGE *page;
        int ret;
        db_pgno_t lpgno;
        void *buf;

        dbenv = dbp->dbenv;
        mpf = dbp->mpf;
        meta = NULL;
        page = NULL;
        buf = NULL;

        if (F_ISSET(dbp, DB_AM_INMEM)) {
                /* Build meta-data page. */
                lpgno = PGNO_BASE_MD;
                if ((ret =
                   __memp_fget(mpf, &lpgno, DB_MPOOL_CREATE, &meta)) != 0)
                        return (ret);
                LSN_NOT_LOGGED(lsn);
                lpgno = __ham_init_meta(dbp, meta, PGNO_BASE_MD, &lsn);
                meta->dbmeta.last_pgno = lpgno;
                if ((ret = __db_log_page(dbp,
                    txn, &lsn, meta->dbmeta.pgno, (PAGE *)meta)) != 0)
                        goto err;
                ret = __memp_fput(mpf, meta, DB_MPOOL_DIRTY);
                meta = NULL;
                if (ret != 0)
                        goto err;

                /* Allocate the final hash bucket. */
                if ((ret =
                    __memp_fget(mpf, &lpgno, DB_MPOOL_CREATE, &page)) != 0)
                        goto err;
                P_INIT(page,
                    dbp->pgsize, lpgno, PGNO_INVALID, PGNO_INVALID, 0, P_HASH);
                LSN_NOT_LOGGED(page->lsn);
                if ((ret =
                    __db_log_page(dbp, txn, &page->lsn, lpgno, page)) != 0)
                        goto err;
                ret = __memp_fput(mpf, page, DB_MPOOL_DIRTY);
                page = NULL;
                if (ret != 0)
                        goto err;
        } else {
                memset(&pdbt, 0, sizeof(pdbt));

                /* Build meta-data page. */
                pginfo.db_pagesize = dbp->pgsize;
                pginfo.type = dbp->type;
                pginfo.flags =
                    F_ISSET(dbp, (DB_AM_CHKSUM | DB_AM_ENCRYPT | DB_AM_SWAP));
                pdbt.data = &pginfo;
                pdbt.size = sizeof(pginfo);
                if ((ret = __os_calloc(dbp->dbenv, 1, dbp->pgsize, &buf)) != 0)
                        return (ret);
                meta = (HMETA *)buf;
                LSN_NOT_LOGGED(lsn);
                lpgno = __ham_init_meta(dbp, meta, PGNO_BASE_MD, &lsn);
                meta->dbmeta.last_pgno = lpgno;
                if ((ret = __db_pgout(dbenv, PGNO_BASE_MD, meta, &pdbt)) != 0)
                        goto err;
                if ((ret = __fop_write(dbenv, txn, name, DB_APP_DATA, fhp,
                    dbp->pgsize, 0, 0, buf, dbp->pgsize, 1, F_ISSET(
                    dbp, DB_AM_NOT_DURABLE) ? DB_LOG_NOT_DURABLE : 0)) != 0)
                        goto err;
                meta = NULL;

                /* Allocate the final hash bucket. */
#ifdef DIAGNOSTIC
                memset(buf, 0, dbp->pgsize);
#endif
                page = (PAGE *)buf;
                P_INIT(page,
                    dbp->pgsize, lpgno, PGNO_INVALID, PGNO_INVALID, 0, P_HASH);
                LSN_NOT_LOGGED(page->lsn);
                if ((ret = __db_pgout(dbenv, lpgno, buf, &pdbt)) != 0)
                        goto err;
                if ((ret = __fop_write(dbenv, txn, name, DB_APP_DATA, fhp,
                    dbp->pgsize, lpgno, 0, buf, dbp->pgsize, 1, F_ISSET(
                    dbp, DB_AM_NOT_DURABLE) ? DB_LOG_NOT_DURABLE : 0)) != 0)
                        goto err;
                page = NULL;
        }

err:    if (buf != NULL)
                __os_free(dbenv, buf);
        else {
                if (meta != NULL)
                        (void)__memp_fput(mpf, meta, 0);
                if (page != NULL)
                        (void)__memp_fput(mpf, page, 0);
        }
        return (ret);
}

/*
 * __ham_new_subdb --
 *      Create the necessary pages to begin a new subdatabase.
 *
 * PUBLIC: int __ham_new_subdb __P((DB *, DB *, DB_TXN *));
 */
int
__ham_new_subdb(mdbp, dbp, txn)
        DB *mdbp, *dbp;
        DB_TXN *txn;
{
        DBC *dbc;
        DB_ENV *dbenv;
        DB_LOCK metalock, mmlock;
        DB_LSN lsn;
        DB_MPOOLFILE *mpf;
        DBMETA *mmeta;
        HMETA *meta;
        PAGE *h;
        int i, ret, t_ret;
        db_pgno_t lpgno, mpgno;

        dbenv = mdbp->dbenv;
        mpf = mdbp->mpf;
        dbc = NULL;
        meta = NULL;
        mmeta = NULL;
        LOCK_INIT(metalock);
        LOCK_INIT(mmlock);

        if ((ret = __db_cursor(mdbp, txn,
            &dbc, CDB_LOCKING(dbenv) ?  DB_WRITECURSOR : 0)) != 0)
                return (ret);

        /* Get and lock the new meta data page. */
        if ((ret = __db_lget(dbc,
            0, dbp->meta_pgno, DB_LOCK_WRITE, 0, &metalock)) != 0)
                goto err;
        if ((ret =
            __memp_fget(mpf, &dbp->meta_pgno, DB_MPOOL_CREATE, &meta)) != 0)
                goto err;

        /* Initialize the new meta-data page. */
        lsn = meta->dbmeta.lsn;
        lpgno = __ham_init_meta(dbp, meta, dbp->meta_pgno, &lsn);

        /*
         * We are about to allocate a set of contiguous buckets (lpgno
         * worth).  We need to get the master meta-data page to figure
         * out where these pages are and to allocate them.  So, lock and
         * get the master meta data page.
         */
        mpgno = PGNO_BASE_MD;
        if ((ret = __db_lget(dbc, 0, mpgno, DB_LOCK_WRITE, 0, &mmlock)) != 0)
                goto err;
        if ((ret = __memp_fget(mpf, &mpgno, 0, &mmeta)) != 0)
                goto err;

        /*
         * Now update the hash meta-data page to reflect where the first
         * set of buckets are actually located.
         */
        meta->spares[0] = mmeta->last_pgno + 1;
        for (i = 0; i < NCACHED && meta->spares[i] != PGNO_INVALID; i++)
                meta->spares[i] = meta->spares[0];

        /* The new meta data page is now complete; log it. */
        if ((ret = __db_log_page(mdbp,
            txn, &meta->dbmeta.lsn, dbp->meta_pgno, (PAGE *)meta)) != 0)
                goto err;

        /* Reflect the group allocation. */
        if (DBENV_LOGGING(dbenv))
                if ((ret = __ham_groupalloc_log(mdbp, txn,
                    &LSN(mmeta), 0, &LSN(mmeta), meta->spares[0],
                    meta->max_bucket + 1, mmeta->free, mmeta->last_pgno)) != 0)
                        goto err;

        /* Release the new meta-data page. */
        if ((ret = __memp_fput(mpf, meta, DB_MPOOL_DIRTY)) != 0)
                goto err;
        meta = NULL;

        lpgno += mmeta->last_pgno;

        /* Now allocate the final hash bucket. */
        if ((ret = __memp_fget(mpf, &lpgno, DB_MPOOL_CREATE, &h)) != 0)
                goto err;

        mmeta->last_pgno = lpgno;
        P_INIT(h, dbp->pgsize, lpgno, PGNO_INVALID, PGNO_INVALID, 0, P_HASH);
        LSN(h) = LSN(mmeta);
        if ((ret = __memp_fput(mpf, h, DB_MPOOL_DIRTY)) != 0)
                goto err;

        /* Now put the master-metadata page back. */
        if ((ret = __memp_fput(mpf, mmeta, DB_MPOOL_DIRTY)) != 0)
                goto err;
        mmeta = NULL;

err:
        if (mmeta != NULL)
                if ((t_ret = __memp_fput(mpf, mmeta, 0)) != 0 && ret == 0)
                        ret = t_ret;
        if ((t_ret = __LPUT(dbc, mmlock)) != 0 && ret == 0)
                ret = t_ret;
        if (meta != NULL)
                if ((t_ret = __memp_fput(mpf, meta, 0)) != 0 && ret == 0)
                        ret = t_ret;
        if ((t_ret = __LPUT(dbc, metalock)) != 0 && ret == 0)
                ret = t_ret;
        if (dbc != NULL)
                if ((t_ret = __db_c_close(dbc)) != 0 && ret == 0)
                        ret = t_ret;
        return (ret);
}

---