diff options
Diffstat (limited to 'db2/btree/bt_page.c')
| -rw-r--r-- | db2/btree/bt_page.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/db2/btree/bt_page.c b/db2/btree/bt_page.c new file mode 100644 index 0000000..7ee74ff --- /dev/null +++ b/db2/btree/bt_page.c @@ -0,0 +1,312 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996, 1997 + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. 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 sccsid[] = "@(#)bt_page.c 10.5 (Sleepycat) 8/18/97"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <errno.h> +#include <stdio.h> +#include <string.h> +#endif + +#include "db_int.h" +#include "db_page.h" +#include "btree.h" + +/* + * __bam_new -- + * Get a new page, preferably from the freelist. + * + * PUBLIC: int __bam_new __P((DB *, u_int32_t, PAGE **)); + */ +int +__bam_new(dbp, type, pagepp) + DB *dbp; + u_int32_t type; + PAGE **pagepp; +{ + BTMETA *meta; + DB_LOCK mlock; + PAGE *h; + db_pgno_t pgno; + int ret; + + meta = NULL; + h = NULL; + mlock = LOCK_INVALID; + + pgno = PGNO_METADATA; + if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &mlock)) != 0) + goto err; + if ((ret = __bam_pget(dbp, (PAGE **)&meta, &pgno, 0)) != 0) + goto err; + + if (meta->free == PGNO_INVALID) { + if ((ret = __bam_pget(dbp, &h, &pgno, DB_MPOOL_NEW)) != 0) + goto err; + ZERO_LSN(h->lsn); + h->pgno = pgno; + } else { + pgno = meta->free; + if ((ret = __bam_pget(dbp, &h, &pgno, 0)) != 0) + goto err; + meta->free = h->next_pgno; + } + + /* Log the change. */ + if (DB_LOGGING(dbp)) { + if ((ret = __bam_pg_alloc_log(dbp->dbenv->lg_info, dbp->txn, + &meta->lsn, 0, dbp->log_fileid, &meta->lsn, &h->lsn, + h->pgno, (u_int32_t)type, meta->free)) != 0) + goto err; + LSN(h) = LSN(meta); + } + + (void)memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY); + (void)__BT_TLPUT(dbp, mlock); + + P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, PGNO_INVALID, 0, type); + *pagepp = h; + return (0); + +err: if (h != NULL) + (void)memp_fput(dbp->mpf, h, 0); + if (meta != NULL) + (void)memp_fput(dbp->mpf, meta, 0); + if (mlock != LOCK_INVALID) + (void)__BT_TLPUT(dbp, mlock); + return (ret); +} + +/* + * __bam_free -- + * Add a page to the head of the freelist. + * + * PUBLIC: int __bam_free __P((DB *, PAGE *)); + */ +int +__bam_free(dbp, h) + DB *dbp; + PAGE *h; +{ + BTMETA *meta; + DBT ldbt; + DB_LOCK mlock; + db_pgno_t pgno; + int is_dirty, ret, t_ret; + + /* + * 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. + */ + is_dirty = 0; + pgno = PGNO_METADATA; + if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &mlock)) != 0) + goto err; + if ((ret = __bam_pget(dbp, (PAGE **)&meta, &pgno, 0)) != 0) { + (void)__BT_TLPUT(dbp, mlock); + goto err; + } + + /* Log the change. */ + if (DB_LOGGING(dbp)) { + memset(&ldbt, 0, sizeof(ldbt)); + ldbt.data = h; + ldbt.size = P_OVERHEAD; + if ((ret = __bam_pg_free_log(dbp->dbenv->lg_info, + dbp->txn, &meta->lsn, 0, dbp->log_fileid, h->pgno, + &meta->lsn, &ldbt, meta->free)) != 0) { + (void)memp_fput(dbp->mpf, (PAGE *)meta, 0); + (void)__BT_TLPUT(dbp, mlock); + return (ret); + } + LSN(h) = LSN(meta); + } + + /* + * The page should have nothing interesting on it, re-initialize it, + * leaving only the page number and the LSN. + */ +#ifdef DEBUG + { db_pgno_t __pgno; DB_LSN __lsn; + __pgno = h->pgno; + __lsn = h->lsn; + memset(h, 0xff, dbp->pgsize); + h->pgno = __pgno; + h->lsn = __lsn; + } +#endif + P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, meta->free, 0, P_INVALID); + + /* Link the page on the metadata free list. */ + meta->free = h->pgno; + + /* Discard the metadata page. */ + ret = memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY); + if ((t_ret = __BT_TLPUT(dbp, mlock)) != 0) + ret = t_ret; + + /* Discard the caller's page reference. */ + is_dirty = DB_MPOOL_DIRTY; +err: if ((t_ret = memp_fput(dbp->mpf, h, is_dirty)) != 0 && ret == 0) + ret = t_ret; + + /* + * XXX + * We have to unlock the caller's page in the caller! + */ + return (ret); +} + +#ifdef DEBUG +/* + * __bam_lt -- + * Print out the list of currently held locks. + */ +int +__bam_lt(dbp) + DB *dbp; +{ + DB_LOCKREQ req; + + if (F_ISSET(dbp, DB_AM_LOCKING)) { + req.op = DB_LOCK_DUMP; + lock_vec(dbp->dbenv->lk_info, dbp->locker, 0, &req, 1, NULL); + } + return (0); +} +#endif + +/* + * __bam_lget -- + * The standard lock get call. + * + * PUBLIC: int __bam_lget __P((DB *, int, db_pgno_t, db_lockmode_t, DB_LOCK *)); + */ +int +__bam_lget(dbp, do_couple, pgno, mode, lockp) + DB *dbp; + int do_couple; + db_pgno_t pgno; + db_lockmode_t mode; + DB_LOCK *lockp; +{ + DB_LOCKREQ couple[2]; + u_int32_t locker; + int ret; + + if (!F_ISSET(dbp, DB_AM_LOCKING)) + return (0); + + locker = dbp->txn == NULL ? dbp->locker : dbp->txn->txnid; + dbp->lock.pgno = pgno; + + /* + * If the object not currently locked, acquire the lock and return, + * otherwise, lock couple. If we fail and it's not a system error, + * convert to EAGAIN. + */ + if (do_couple) { + couple[0].op = DB_LOCK_GET; + couple[0].obj = &dbp->lock_dbt; + couple[0].mode = mode; + couple[1].op = DB_LOCK_PUT; + couple[1].lock = *lockp; + + ret = lock_vec(dbp->dbenv->lk_info, locker, 0, couple, 2, NULL); + if (ret != 0) { + /* If we fail, discard the lock we held. */ + __bam_lput(dbp, *lockp); + + return (ret < 0 ? EAGAIN : ret); + } + *lockp = couple[0].lock; + } else { + ret = lock_get(dbp->dbenv->lk_info, + locker, 0, &dbp->lock_dbt, mode, lockp); + return (ret < 0 ? EAGAIN : ret); + } + return (0); +} + +/* + * __bam_lput -- + * The standard lock put call. + * + * PUBLIC: int __bam_lput __P((DB *, DB_LOCK)); + */ +int +__bam_lput(dbp, lock) + DB *dbp; + DB_LOCK lock; +{ + return (__BT_LPUT(dbp, lock)); +} + +/* + * __bam_pget -- + * The standard page get call. + * + * PUBLIC: int __bam_pget __P((DB *, PAGE **, db_pgno_t *, int)); + */ +int +__bam_pget(dbp, hp, pgnop, mflags) + DB *dbp; + PAGE **hp; + db_pgno_t *pgnop; + int mflags; +{ + return (memp_fget((dbp)->mpf, + pgnop, mflags, hp) == 0 ? 0 : __db_pgerr(dbp, *pgnop)); +} |