1/*-
2 * See the file LICENSE for redistribution information.
3 *
4 * Copyright (c) 1996, 1997, 1998
5 *	Sleepycat Software.  All rights reserved.
6 */
7/*
8 * Copyright (c) 1990, 1993, 1994, 1995, 1996
9 *	Keith Bostic.  All rights reserved.
10 */
11/*
12 * Copyright (c) 1990, 1993, 1994, 1995
13 *	The Regents of the University of California.  All rights reserved.
14 *
15 * This code is derived from software contributed to Berkeley by
16 * Mike Olson.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 *    notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 *    notice, this list of conditions and the following disclaimer in the
25 *    documentation and/or other materials provided with the distribution.
26 * 3. All advertising materials mentioning features or use of this software
27 *    must display the following acknowledgement:
28 *	This product includes software developed by the University of
29 *	California, Berkeley and its contributors.
30 * 4. Neither the name of the University nor the names of its contributors
31 *    may be used to endorse or promote products derived from this software
32 *    without specific prior written permission.
33 *
34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 */
46
47#include "config.h"
48
49#ifndef lint
50static const char sccsid[] = "@(#)bt_page.c	10.17 (Sleepycat) 1/3/99";
51#endif /* not lint */
52
53#ifndef NO_SYSTEM_INCLUDES
54#include <sys/types.h>
55
56#include <errno.h>
57#include <string.h>
58#endif
59
60#include "db_int.h"
61#include "db_page.h"
62#include "btree.h"
63
64/*
65 * __bam_new --
66 *	Get a new page, preferably from the freelist.
67 *
68 * PUBLIC: int __bam_new __P((DBC *, u_int32_t, PAGE **));
69 */
70int
71__bam_new(dbc, type, pagepp)
72	DBC *dbc;
73	u_int32_t type;
74	PAGE **pagepp;
75{
76	BTMETA *meta;
77	DB *dbp;
78	DB_LOCK metalock;
79	PAGE *h;
80	db_pgno_t pgno;
81	int ret;
82
83	dbp = dbc->dbp;
84	meta = NULL;
85	h = NULL;
86	metalock = LOCK_INVALID;
87
88	pgno = PGNO_METADATA;
89	if ((ret = __bam_lget(dbc, 0, pgno, DB_LOCK_WRITE, &metalock)) != 0)
90		goto err;
91	if ((ret = memp_fget(dbp->mpf, &pgno, 0, (PAGE **)&meta)) != 0)
92		goto err;
93
94	if (meta->free == PGNO_INVALID) {
95		if ((ret = memp_fget(dbp->mpf, &pgno, DB_MPOOL_NEW, &h)) != 0)
96			goto err;
97		ZERO_LSN(h->lsn);
98		h->pgno = pgno;
99	} else {
100		pgno = meta->free;
101		if ((ret = memp_fget(dbp->mpf, &pgno, 0, &h)) != 0)
102			goto err;
103		meta->free = h->next_pgno;
104	}
105
106	/* Log the change. */
107	if (DB_LOGGING(dbc)) {
108		if ((ret = __bam_pg_alloc_log(dbp->dbenv->lg_info, dbc->txn,
109		    &meta->lsn, 0, dbp->log_fileid, &meta->lsn, &h->lsn,
110		    h->pgno, (u_int32_t)type, meta->free)) != 0)
111			goto err;
112		LSN(h) = LSN(meta);
113	}
114
115	(void)memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
116	(void)__BT_TLPUT(dbc, metalock);
117
118	P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, PGNO_INVALID, 0, type);
119	*pagepp = h;
120	return (0);
121
122err:	if (h != NULL)
123		(void)memp_fput(dbp->mpf, h, 0);
124	if (meta != NULL)
125		(void)memp_fput(dbp->mpf, meta, 0);
126	if (metalock != LOCK_INVALID)
127		(void)__BT_TLPUT(dbc, metalock);
128	return (ret);
129}
130
131/*
132 * __bam_lput --
133 *	The standard lock put call.
134 *
135 * PUBLIC: int __bam_lput __P((DBC *, DB_LOCK));
136 */
137int
138__bam_lput(dbc, lock)
139	DBC *dbc;
140	DB_LOCK lock;
141{
142	return (__BT_LPUT(dbc, lock));
143}
144
145/*
146 * __bam_free --
147 *	Add a page to the head of the freelist.
148 *
149 * PUBLIC: int __bam_free __P((DBC *, PAGE *));
150 */
151int
152__bam_free(dbc, h)
153	DBC *dbc;
154	PAGE *h;
155{
156	BTMETA *meta;
157	DB *dbp;
158	DBT ldbt;
159	DB_LOCK metalock;
160	db_pgno_t pgno;
161	u_int32_t dirty_flag;
162	int ret, t_ret;
163
164	dbp = dbc->dbp;
165
166	/*
167	 * Retrieve the metadata page and insert the page at the head of
168	 * the free list.  If either the lock get or page get routines
169	 * fail, then we need to put the page with which we were called
170	 * back because our caller assumes we take care of it.
171	 */
172	dirty_flag = 0;
173	pgno = PGNO_METADATA;
174	if ((ret = __bam_lget(dbc, 0, pgno, DB_LOCK_WRITE, &metalock)) != 0)
175		goto err;
176	if ((ret = memp_fget(dbp->mpf, &pgno, 0, (PAGE **)&meta)) != 0) {
177		(void)__BT_TLPUT(dbc, metalock);
178		goto err;
179	}
180
181	/* Log the change. */
182	if (DB_LOGGING(dbc)) {
183		memset(&ldbt, 0, sizeof(ldbt));
184		ldbt.data = h;
185		ldbt.size = P_OVERHEAD;
186		if ((ret = __bam_pg_free_log(dbp->dbenv->lg_info,
187		    dbc->txn, &meta->lsn, 0, dbp->log_fileid, h->pgno,
188		    &meta->lsn, &ldbt, meta->free)) != 0) {
189			(void)memp_fput(dbp->mpf, (PAGE *)meta, 0);
190			(void)__BT_TLPUT(dbc, metalock);
191			return (ret);
192		}
193		LSN(h) = LSN(meta);
194	}
195
196	/*
197	 * The page should have nothing interesting on it, re-initialize it,
198	 * leaving only the page number and the LSN.
199	 */
200#ifdef DIAGNOSTIC
201	{ db_pgno_t __pgno; DB_LSN __lsn;
202		__pgno = h->pgno;
203		__lsn = h->lsn;
204		memset(h, 0xdb, dbp->pgsize);
205		h->pgno = __pgno;
206		h->lsn = __lsn;
207	}
208#endif
209	P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, meta->free, 0, P_INVALID);
210
211	/* Link the page on the metadata free list. */
212	meta->free = h->pgno;
213
214	/* Discard the metadata page. */
215	ret = memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
216	if ((t_ret = __BT_TLPUT(dbc, metalock)) != 0)
217		ret = t_ret;
218
219	/* Discard the caller's page reference. */
220	dirty_flag = DB_MPOOL_DIRTY;
221err:	if ((t_ret = memp_fput(dbp->mpf, h, dirty_flag)) != 0 && ret == 0)
222		ret = t_ret;
223
224	/*
225	 * XXX
226	 * We have to unlock the caller's page in the caller!
227	 */
228	return (ret);
229}
230
231#ifdef DEBUG
232/*
233 * __bam_lt --
234 *	Print out the list of locks currently held by a cursor.
235 *
236 * PUBLIC: int __bam_lt __P((DBC *));
237 */
238int
239__bam_lt(dbc)
240	DBC *dbc;
241{
242	DB *dbp;
243	DB_LOCKREQ req;
244
245	dbp = dbc->dbp;
246	if (F_ISSET(dbp, DB_AM_LOCKING)) {
247		req.op = DB_LOCK_DUMP;
248		lock_vec(dbp->dbenv->lk_info, dbc->locker, 0, &req, 1, NULL);
249	}
250	return (0);
251}
252#endif
253
254/*
255 * __bam_lget --
256 *	The standard lock get call.
257 *
258 * PUBLIC: int __bam_lget
259 * PUBLIC:    __P((DBC *, int, db_pgno_t, db_lockmode_t, DB_LOCK *));
260 */
261int
262__bam_lget(dbc, do_couple, pgno, mode, lockp)
263	DBC *dbc;
264	int do_couple;
265	db_pgno_t pgno;
266	db_lockmode_t mode;
267	DB_LOCK *lockp;
268{
269	DB *dbp;
270	DB_LOCKREQ couple[2];
271	int ret;
272
273	dbp = dbc->dbp;
274
275	if (!F_ISSET(dbp, DB_AM_LOCKING)) {
276		*lockp = LOCK_INVALID;
277		return (0);
278	}
279
280	dbc->lock.pgno = pgno;
281
282	/*
283	 * If the object not currently locked, acquire the lock and return,
284	 * otherwise, lock couple.  If we fail and it's not a system error,
285	 * convert to EAGAIN.
286	 */
287	if (do_couple) {
288		couple[0].op = DB_LOCK_GET;
289		couple[0].obj = &dbc->lock_dbt;
290		couple[0].mode = mode;
291		couple[1].op = DB_LOCK_PUT;
292		couple[1].lock = *lockp;
293
294		if (dbc->txn == NULL)
295			ret = lock_vec(dbp->dbenv->lk_info,
296			    dbc->locker, 0, couple, 2, NULL);
297		else
298			ret = lock_tvec(dbp->dbenv->lk_info,
299			    dbc->txn, 0, couple, 2, NULL);
300		if (ret != 0) {
301			/* If we fail, discard the lock we held. */
302			__BT_LPUT(dbc, *lockp);
303
304			return (ret < 0 ? EAGAIN : ret);
305		}
306		*lockp = couple[0].lock;
307	} else {
308		if (dbc->txn == NULL)
309			ret = lock_get(dbp->dbenv->lk_info,
310			    dbc->locker, 0, &dbc->lock_dbt, mode, lockp);
311		else
312			ret = lock_tget(dbp->dbenv->lk_info,
313			    dbc->txn, 0, &dbc->lock_dbt, mode, lockp);
314		 return (ret < 0 ? EAGAIN : ret);
315	}
316	return (0);
317}
318