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Diffstat (limited to 'db2/btree/bt_page.c')
-rw-r--r--db2/btree/bt_page.c312
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 0000000000..7ee74ffcf8
--- /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));
+}
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-12-12 00:09:49 +0000