aboutsummaryrefslogtreecommitdiff
path: root/db2/btree/bt_page.c
blob: 87f281139877db6701f4a345af8e00bcd1304430 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998
 *	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	10.12 (Sleepycat) 5/6/98";
#endif /* not lint */

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

#include <errno.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 metalock;
	PAGE *h;
	db_pgno_t pgno;
	int ret;

	meta = NULL;
	h = NULL;
	metalock = LOCK_INVALID;

	pgno = PGNO_METADATA;
	if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &metalock)) != 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, metalock);

	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 (metalock != LOCK_INVALID)
		(void)__BT_TLPUT(dbp, metalock);
	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 metalock;
	db_pgno_t pgno;
	u_int32_t dirty_flag;
	int 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.
	 */
	dirty_flag = 0;
	pgno = PGNO_METADATA;
	if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &metalock)) != 0)
		goto err;
	if ((ret = __bam_pget(dbp, (PAGE **)&meta, &pgno, 0)) != 0) {
		(void)__BT_TLPUT(dbp, metalock);
		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, metalock);
			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 DIAGNOSTIC
	{ 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, metalock)) != 0)
		ret = t_ret;

	/* Discard the caller's page reference. */
	dirty_flag = DB_MPOOL_DIRTY;
err:	if ((t_ret = memp_fput(dbp->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
/*
 * __bam_lt --
 *	Print out the list of currently held locks.
 *
 * PUBLIC: int __bam_lt __P((DB *));
 */
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)) {
		*lockp = LOCK_INVALID;
		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 *, u_int32_t));
 */
int
__bam_pget(dbp, hp, pgnop, mpool_flags)
	DB *dbp;
	PAGE **hp;
	db_pgno_t *pgnop;
	u_int32_t mpool_flags;
{
	return (memp_fget((dbp)->mpf,
	    pgnop, mpool_flags, hp) == 0 ? 0 : __db_pgerr(dbp, *pgnop));
}