db2/btree/bt_page.c

   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
  50 static const char sccsid[] = "@(#)bt_page.c     10.12 (Sleepycat) 5/6/98";
  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((DB *, u_int32_t, PAGE **));
  69  */
  70 int
  71 __bam_new(dbp, type, pagepp)
  72         DB *dbp;
  73         u_int32_t type;
  74         PAGE **pagepp;
  75 {
  76         BTMETA *meta;
  77         DB_LOCK metalock;
  78         PAGE *h;
  79         db_pgno_t pgno;
  80         int ret;
  81
  82         meta = NULL;
  83         h = NULL;
  84         metalock = LOCK_INVALID;
  85
  86         pgno = PGNO_METADATA;
  87         if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &metalock)) != 0)
  88                 goto err;
  89         if ((ret = __bam_pget(dbp, (PAGE **)&meta, &pgno, 0)) != 0)
  90                 goto err;
  91
  92         if (meta->free == PGNO_INVALID) {
  93                 if ((ret = __bam_pget(dbp, &h, &pgno, DB_MPOOL_NEW)) != 0)
  94                         goto err;
  95                 ZERO_LSN(h->lsn);
  96                 h->pgno = pgno;
  97         } else {
  98                 pgno = meta->free;
  99                 if ((ret = __bam_pget(dbp, &h, &pgno, 0)) != 0)
 100                         goto err;
 101                 meta->free = h->next_pgno;
 102         }
 103
 104         /* Log the change. */
 105         if (DB_LOGGING(dbp)) {
 106                 if ((ret = __bam_pg_alloc_log(dbp->dbenv->lg_info, dbp->txn,
 107                     &meta->lsn, 0, dbp->log_fileid, &meta->lsn, &h->lsn,
 108                     h->pgno, (u_int32_t)type, meta->free)) != 0)
 109                         goto err;
 110                 LSN(h) = LSN(meta);
 111         }
 112
 113         (void)memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
 114         (void)__BT_TLPUT(dbp, metalock);
 115
 116         P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, PGNO_INVALID, 0, type);
 117         *pagepp = h;
 118         return (0);
 119
 120 err:    if (h != NULL)
 121                 (void)memp_fput(dbp->mpf, h, 0);
 122         if (meta != NULL)
 123                 (void)memp_fput(dbp->mpf, meta, 0);
 124         if (metalock != LOCK_INVALID)
 125                 (void)__BT_TLPUT(dbp, metalock);
 126         return (ret);
 127 }
 128
 129 /*
 130  * __bam_free --
 131  *      Add a page to the head of the freelist.
 132  *
 133  * PUBLIC: int __bam_free __P((DB *, PAGE *));
 134  */
 135 int
 136 __bam_free(dbp, h)
 137         DB *dbp;
 138         PAGE *h;
 139 {
 140         BTMETA *meta;
 141         DBT ldbt;
 142         DB_LOCK metalock;
 143         db_pgno_t pgno;
 144         u_int32_t dirty_flag;
 145         int ret, t_ret;
 146
 147         /*
 148          * Retrieve the metadata page and insert the page at the head of
 149          * the free list.  If either the lock get or page get routines
 150          * fail, then we need to put the page with which we were called
 151          * back because our caller assumes we take care of it.
 152          */
 153         dirty_flag = 0;
 154         pgno = PGNO_METADATA;
 155         if ((ret = __bam_lget(dbp, 0, pgno, DB_LOCK_WRITE, &metalock)) != 0)
 156                 goto err;
 157         if ((ret = __bam_pget(dbp, (PAGE **)&meta, &pgno, 0)) != 0) {
 158                 (void)__BT_TLPUT(dbp, metalock);
 159                 goto err;
 160         }
 161
 162         /* Log the change. */
 163         if (DB_LOGGING(dbp)) {
 164                 memset(&ldbt, 0, sizeof(ldbt));
 165                 ldbt.data = h;
 166                 ldbt.size = P_OVERHEAD;
 167                 if ((ret = __bam_pg_free_log(dbp->dbenv->lg_info,
 168                     dbp->txn, &meta->lsn, 0, dbp->log_fileid, h->pgno,
 169                     &meta->lsn, &ldbt, meta->free)) != 0) {
 170                         (void)memp_fput(dbp->mpf, (PAGE *)meta, 0);
 171                         (void)__BT_TLPUT(dbp, metalock);
 172                         return (ret);
 173                 }
 174                 LSN(h) = LSN(meta);
 175         }
 176
 177         /*
 178          * The page should have nothing interesting on it, re-initialize it,
 179          * leaving only the page number and the LSN.
 180          */
 181 #ifdef DIAGNOSTIC
 182         { db_pgno_t __pgno; DB_LSN __lsn;
 183                 __pgno = h->pgno;
 184                 __lsn = h->lsn;
 185                 memset(h, 0xff, dbp->pgsize);
 186                 h->pgno = __pgno;
 187                 h->lsn = __lsn;
 188         }
 189 #endif
 190         P_INIT(h, dbp->pgsize, h->pgno, PGNO_INVALID, meta->free, 0, P_INVALID);
 191
 192         /* Link the page on the metadata free list. */
 193         meta->free = h->pgno;
 194
 195         /* Discard the metadata page. */
 196         ret = memp_fput(dbp->mpf, (PAGE *)meta, DB_MPOOL_DIRTY);
 197         if ((t_ret = __BT_TLPUT(dbp, metalock)) != 0)
 198                 ret = t_ret;
 199
 200         /* Discard the caller's page reference. */
 201         dirty_flag = DB_MPOOL_DIRTY;
 202 err:    if ((t_ret = memp_fput(dbp->mpf, h, dirty_flag)) != 0 && ret == 0)
 203                 ret = t_ret;
 204
 205         /*
 206          * XXX
 207          * We have to unlock the caller's page in the caller!
 208          */
 209         return (ret);
 210 }
 211
 212 #ifdef DEBUG
 213 /*
 214  * __bam_lt --
 215  *      Print out the list of currently held locks.
 216  *
 217  * PUBLIC: int __bam_lt __P((DB *));
 218  */
 219 int
 220 __bam_lt(dbp)
 221         DB *dbp;
 222 {
 223         DB_LOCKREQ req;
 224
 225         if (F_ISSET(dbp, DB_AM_LOCKING)) {
 226                 req.op = DB_LOCK_DUMP;
 227                 lock_vec(dbp->dbenv->lk_info, dbp->locker, 0, &req, 1, NULL);
 228         }
 229         return (0);
 230 }
 231 #endif
 232
 233 /*
 234  * __bam_lget --
 235  *      The standard lock get call.
 236  *
 237  * PUBLIC: int __bam_lget __P((DB *, int, db_pgno_t, db_lockmode_t, DB_LOCK *));
 238  */
 239 int
 240 __bam_lget(dbp, do_couple, pgno, mode, lockp)
 241         DB *dbp;
 242         int do_couple;
 243         db_pgno_t pgno;
 244         db_lockmode_t mode;
 245         DB_LOCK *lockp;
 246 {
 247         DB_LOCKREQ couple[2];
 248         u_int32_t locker;
 249         int ret;
 250
 251         if (!F_ISSET(dbp, DB_AM_LOCKING)) {
 252                 *lockp = LOCK_INVALID;
 253                 return (0);
 254         }
 255
 256         locker = dbp->txn == NULL ? dbp->locker : dbp->txn->txnid;
 257         dbp->lock.pgno = pgno;
 258
 259         /*
 260          * If the object not currently locked, acquire the lock and return,
 261          * otherwise, lock couple.  If we fail and it's not a system error,
 262          * convert to EAGAIN.
 263          */
 264         if (do_couple) {
 265                 couple[0].op = DB_LOCK_GET;
 266                 couple[0].obj = &dbp->lock_dbt;
 267                 couple[0].mode = mode;
 268                 couple[1].op = DB_LOCK_PUT;
 269                 couple[1].lock = *lockp;
 270
 271                 ret = lock_vec(dbp->dbenv->lk_info, locker, 0, couple, 2, NULL);
 272                 if (ret != 0) {
 273                         /* If we fail, discard the lock we held. */
 274                         __bam_lput(dbp, *lockp);
 275
 276                         return (ret < 0 ? EAGAIN : ret);
 277                 }
 278                 *lockp = couple[0].lock;
 279         } else {
 280                  ret = lock_get(dbp->dbenv->lk_info,
 281                      locker, 0, &dbp->lock_dbt, mode, lockp);
 282                  return (ret < 0 ? EAGAIN : ret);
 283         }
 284         return (0);
 285 }
 286
 287 /*
 288  * __bam_lput --
 289  *      The standard lock put call.
 290  *
 291  * PUBLIC: int __bam_lput __P((DB *, DB_LOCK));
 292  */
 293 int
 294 __bam_lput(dbp, lock)
 295         DB *dbp;
 296         DB_LOCK lock;
 297 {
 298         return (__BT_LPUT(dbp, lock));
 299 }
 300
 301 /*
 302  * __bam_pget --
 303  *      The standard page get call.
 304  *
 305  * PUBLIC: int __bam_pget __P((DB *, PAGE **, db_pgno_t *, u_int32_t));
 306  */
 307 int
 308 __bam_pget(dbp, hp, pgnop, mpool_flags)
 309         DB *dbp;
 310         PAGE **hp;
 311         db_pgno_t *pgnop;
 312         u_int32_t mpool_flags;
 313 {
 314         return (memp_fget((dbp)->mpf,
 315             pgnop, mpool_flags, hp) == 0 ? 0 : __db_pgerr(dbp, *pgnop));
 316 }