db_meta.c
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- /*-
- * See the file LICENSE for redistribution information.
- *
- * Copyright (c) 1996-2002
- * 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: db_meta.c,v 11.61 2002/08/08 03:57:48 bostic Exp $";
- #endif /* not lint */
- #ifndef NO_SYSTEM_INCLUDES
- #include <sys/types.h>
- #include <string.h>
- #endif
- #include "db_int.h"
- #include "dbinc/db_page.h"
- #include "dbinc/db_shash.h"
- #include "dbinc/lock.h"
- #include "dbinc/db_am.h"
- static void __db_init_meta __P((void *, u_int32_t, db_pgno_t, u_int32_t));
- /*
- * __db_init_meta --
- * Helper function for __db_new that initializes the important fields in
- * a meta-data page (used instead of P_INIT). We need to make sure that we
- * retain the page number and LSN of the existing page.
- */
- static void
- __db_init_meta(p, pgsize, pgno, pgtype)
- void *p;
- u_int32_t pgsize;
- db_pgno_t pgno;
- u_int32_t pgtype;
- {
- DB_LSN save_lsn;
- DBMETA *meta;
- meta = (DBMETA *)p;
- save_lsn = meta->lsn;
- memset(meta, 0, sizeof(DBMETA));
- meta->lsn = save_lsn;
- meta->pagesize = pgsize;
- meta->pgno = pgno;
- meta->type = (u_int8_t)pgtype;
- }
- /*
- * __db_new --
- * Get a new page, preferably from the freelist.
- *
- * PUBLIC: int __db_new __P((DBC *, u_int32_t, PAGE **));
- */
- int
- __db_new(dbc, type, pagepp)
- DBC *dbc;
- u_int32_t type;
- PAGE **pagepp;
- {
- DBMETA *meta;
- DB *dbp;
- DB_LOCK metalock;
- DB_LSN lsn;
- DB_MPOOLFILE *mpf;
- PAGE *h;
- db_pgno_t pgno, newnext;
- int meta_flags, extend, ret;
- meta = NULL;
- meta_flags = 0;
- dbp = dbc->dbp;
- mpf = dbp->mpf;
- h = NULL;
- newnext = PGNO_INVALID;
- pgno = PGNO_BASE_MD;
- if ((ret = __db_lget(dbc,
- LCK_ALWAYS, pgno, DB_LOCK_WRITE, 0, &metalock)) != 0)
- goto err;
- if ((ret = mpf->get(mpf, &pgno, 0, (PAGE **)&meta)) != 0)
- goto err;
- if (meta->free == PGNO_INVALID) {
- pgno = meta->last_pgno + 1;
- ZERO_LSN(lsn);
- extend = 1;
- } else {
- pgno = meta->free;
- if ((ret = mpf->get(mpf, &pgno, 0, &h)) != 0)
- goto err;
- /*
- * We want to take the first page off the free list and
- * then set meta->free to the that page's next_pgno, but
- * we need to log the change first.
- */
- newnext = h->next_pgno;
- lsn = h->lsn;
- extend = 0;
- }
- /*
- * Log the allocation before fetching the new page. If we
- * don't have room in the log then we don't want to tell
- * mpool to extend the file.
- */
- if (DBC_LOGGING(dbc)) {
- if ((ret = __db_pg_alloc_log(dbp, dbc->txn, &LSN(meta), 0,
- &LSN(meta), PGNO_BASE_MD, &lsn, pgno,
- (u_int32_t)type, newnext)) != 0)
- goto err;
- } else
- LSN_NOT_LOGGED(LSN(meta));
- meta_flags = DB_MPOOL_DIRTY;
- meta->free = newnext;
- if (extend == 1) {
- meta->last_pgno++;
- if ((ret = mpf->get(mpf, &pgno, DB_MPOOL_NEW, &h)) != 0)
- goto err;
- ZERO_LSN(h->lsn);
- h->pgno = pgno;
- DB_ASSERT(pgno == meta->last_pgno);
- }
- LSN(h) = LSN(meta);
- DB_ASSERT(TYPE(h) == P_INVALID);
- if (TYPE(h) != P_INVALID)
- return (__db_panic(dbp->dbenv, EINVAL));
- (void)mpf->put(mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
- (void)__TLPUT(dbc, metalock);
- switch (type) {
- case P_BTREEMETA:
- case P_HASHMETA:
- case P_QAMMETA:
- __db_init_meta(h, dbp->pgsize, h->pgno, type);
- break;
- default:
- P_INIT(h, dbp->pgsize,
- h->pgno, PGNO_INVALID, PGNO_INVALID, 0, type);
- break;
- }
- /*
- * If dirty reads are enabled and we are in a transaction, we could
- * abort this allocation after the page(s) pointing to this
- * one have their locks downgraded. This would permit dirty readers
- * to access this page which is ok, but they must be off the
- * page when we abort. This will also prevent updates happening
- * to this page until we commit.
- */
- if (F_ISSET(dbc->dbp, DB_AM_DIRTY) && dbc->txn != NULL) {
- if ((ret = __db_lget(dbc, 0,
- h->pgno, DB_LOCK_WWRITE, 0, &metalock)) != 0)
- goto err;
- }
- *pagepp = h;
- return (0);
- err: if (h != NULL)
- (void)mpf->put(mpf, h, 0);
- if (meta != NULL)
- (void)mpf->put(mpf, meta, meta_flags);
- (void)__TLPUT(dbc, metalock);
- return (ret);
- }
- /*
- * __db_free --
- * Add a page to the head of the freelist.
- *
- * PUBLIC: int __db_free __P((DBC *, PAGE *));
- */
- int
- __db_free(dbc, h)
- DBC *dbc;
- PAGE *h;
- {
- DBMETA *meta;
- DB *dbp;
- DBT ldbt;
- DB_LOCK metalock;
- DB_MPOOLFILE *mpf;
- db_pgno_t pgno;
- u_int32_t dirty_flag;
- int ret, t_ret;
- dbp = dbc->dbp;
- mpf = dbp->mpf;
- /*
- * 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 = __db_lget(dbc,
- LCK_ALWAYS, pgno, DB_LOCK_WRITE, 0, &metalock)) != 0)
- goto err;
- if ((ret = mpf->get(mpf, &pgno, 0, (PAGE **)&meta)) != 0) {
- (void)__TLPUT(dbc, metalock);
- goto err;
- }
- DB_ASSERT(h->pgno != meta->free);
- /* Log the change. */
- if (DBC_LOGGING(dbc)) {
- memset(&ldbt, 0, sizeof(ldbt));
- ldbt.data = h;
- ldbt.size = P_OVERHEAD(dbp);
- if ((ret = __db_pg_free_log(dbp,
- dbc->txn, &LSN(meta), 0, h->pgno,
- &LSN(meta), PGNO_BASE_MD, &ldbt, meta->free)) != 0) {
- (void)mpf->put(mpf, (PAGE *)meta, 0);
- (void)__TLPUT(dbc, metalock);
- goto err;
- }
- } else
- LSN_NOT_LOGGED(LSN(meta));
- LSN(h) = LSN(meta);
- P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, meta->free, 0, P_INVALID);
- meta->free = h->pgno;
- /* Discard the metadata page. */
- if ((t_ret =
- mpf->put(mpf, (PAGE *)meta, DB_MPOOL_DIRTY)) != 0 && ret == 0)
- ret = t_ret;
- if ((t_ret = __TLPUT(dbc, metalock)) != 0 && ret == 0)
- ret = t_ret;
- /* Discard the caller's page reference. */
- dirty_flag = DB_MPOOL_DIRTY;
- err: if ((t_ret = mpf->put(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
- /*
- * __db_lprint --
- * Print out the list of locks currently held by a cursor.
- *
- * PUBLIC: int __db_lprint __P((DBC *));
- */
- int
- __db_lprint(dbc)
- DBC *dbc;
- {
- DB *dbp;
- DB_LOCKREQ req;
- dbp = dbc->dbp;
- if (LOCKING_ON(dbp->dbenv)) {
- req.op = DB_LOCK_DUMP;
- dbp->dbenv->lock_vec(dbp->dbenv, dbc->locker, 0, &req, 1, NULL);
- }
- return (0);
- }
- #endif
- /*
- * Implement the rules for transactional locking. We can release the previous
- * lock if we are not in a transaction or COUPLE_ALWAYS is specifed (used in
- * record locking). If we are doing dirty reads then we can release read locks
- * and down grade write locks.
- */
- #define DB_PUT_ACTION(dbc, action, lockp)
- (((action == LCK_COUPLE || action == LCK_COUPLE_ALWAYS) &&
- LOCK_ISSET(*lockp)) ?
- (dbc->txn == NULL || action == LCK_COUPLE_ALWAYS ||
- (F_ISSET(dbc, DBC_DIRTY_READ) &&
- (lockp)->mode == DB_LOCK_DIRTY)) ? LCK_COUPLE :
- (F_ISSET((dbc)->dbp, DB_AM_DIRTY) &&
- (lockp)->mode == DB_LOCK_WRITE) ? LCK_DOWNGRADE : 0 : 0)
- /*
- * __db_lget --
- * The standard lock get call.
- *
- * PUBLIC: int __db_lget __P((DBC *,
- * PUBLIC: int, db_pgno_t, db_lockmode_t, u_int32_t, DB_LOCK *));
- */
- int
- __db_lget(dbc, action, pgno, mode, lkflags, lockp)
- DBC *dbc;
- int action;
- db_pgno_t pgno;
- db_lockmode_t mode;
- u_int32_t lkflags;
- DB_LOCK *lockp;
- {
- DB *dbp;
- DB_ENV *dbenv;
- DB_LOCKREQ couple[2], *reqp;
- DB_TXN *txn;
- int has_timeout, ret;
- dbp = dbc->dbp;
- dbenv = dbp->dbenv;
- txn = dbc->txn;
- /*
- * We do not always check if we're configured for locking before
- * calling __db_lget to acquire the lock.
- */
- if (CDB_LOCKING(dbenv) ||
- !LOCKING_ON(dbenv) || F_ISSET(dbc, DBC_COMPENSATE) ||
- (F_ISSET(dbc, DBC_RECOVER) &&
- (action != LCK_ROLLBACK || F_ISSET(dbenv, DB_ENV_REP_CLIENT))) ||
- (action != LCK_ALWAYS && F_ISSET(dbc, DBC_OPD))) {
- LOCK_INIT(*lockp);
- 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 (F_ISSET(dbc, DBC_DIRTY_READ) && mode == DB_LOCK_READ)
- mode = DB_LOCK_DIRTY;
- has_timeout = txn != NULL && F_ISSET(txn, TXN_LOCKTIMEOUT);
- switch (DB_PUT_ACTION(dbc, action, lockp)) {
- case LCK_COUPLE:
- lck_couple: couple[0].op = has_timeout? DB_LOCK_GET_TIMEOUT : DB_LOCK_GET;
- couple[0].obj = &dbc->lock_dbt;
- couple[0].mode = mode;
- if (action == LCK_COUPLE_ALWAYS)
- action = LCK_COUPLE;
- UMRW_SET(couple[0].timeout);
- if (has_timeout)
- couple[0].timeout = txn->lock_timeout;
- if (action == LCK_COUPLE) {
- couple[1].op = DB_LOCK_PUT;
- couple[1].lock = *lockp;
- }
- ret = dbenv->lock_vec(dbenv, dbc->locker,
- lkflags, couple, action == LCK_COUPLE ? 2 : 1, &reqp);
- if (ret == 0 || reqp == &couple[1])
- *lockp = couple[0].lock;
- break;
- case LCK_DOWNGRADE:
- if ((ret = dbenv->lock_downgrade(
- dbenv, lockp, DB_LOCK_WWRITE, 0)) != 0)
- return (ret);
- /* FALL THROUGH */
- default:
- if (has_timeout)
- goto lck_couple;
- ret = dbenv->lock_get(dbenv,
- dbc->locker, lkflags, &dbc->lock_dbt, mode, lockp);
- break;
- }
- return (ret);
- }
- /*
- * __db_lput --
- * The standard lock put call.
- *
- * PUBLIC: int __db_lput __P((DBC *, DB_LOCK *));
- */
- int
- __db_lput(dbc, lockp)
- DBC *dbc;
- DB_LOCK *lockp;
- {
- DB_ENV *dbenv;
- int ret;
- dbenv = dbc->dbp->dbenv;
- switch (DB_PUT_ACTION(dbc, LCK_COUPLE, lockp)) {
- case LCK_COUPLE:
- ret = dbenv->lock_put(dbenv, lockp);
- break;
- case LCK_DOWNGRADE:
- ret = __lock_downgrade(dbenv, lockp, DB_LOCK_WWRITE, 0);
- break;
- default:
- ret = 0;
- break;
- }
- return (ret);
- }