bt_curadj.c

这是国外的resip协议栈

	    ldbp != NULL && ldbp->adj_fileid == dbp->adj_fileid;
	    ldbp = LIST_NEXT(ldbp, dblistlinks)) {
loop:		MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
		for (dbc = TAILQ_FIRST(&ldbp->active_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			/* Find cursors pointing to this record. */
			orig_cp = (BTREE_CURSOR *)dbc->internal;
			if (orig_cp->pgno != fpgno || orig_cp->indx != fi)
				continue;

			/*
			 * Since we rescan the list see if this is already
			 * converted.
			 */
			if (orig_cp->opd != NULL)
				continue;

			MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
			/* [#8032]
			DB_ASSERT(!STD_LOCKING(dbc) ||
			    orig_cp->lock_mode != DB_LOCK_NG);
			*/
			if ((ret = __bam_opd_cursor(dbp,
			    dbc, first, tpgno, ti)) !=0)
				return (ret);
			if (my_txn != NULL && dbc->txn != my_txn)
				found = 1;
			/* We released the mutex to get a cursor, start over. */
			goto loop;
		}
		MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
	}
	MUTEX_THREAD_UNLOCK(dbenv, dbenv->dblist_mutexp);

	if (found != 0 && DBC_LOGGING(my_dbc)) {
		if ((ret = __bam_curadj_log(dbp, my_dbc->txn,
		    &lsn, 0, DB_CA_DUP, fpgno, tpgno, 0, first, fi, ti)) != 0)
			return (ret);
	}
	return (0);
}

/*
 * __bam_ca_undodup --
 *	Adjust the cursors when returning items to a leaf page
 *	from a duplicate page.
 *	Called only during undo processing.
 *
 * PUBLIC: int __bam_ca_undodup __P((DB *,
 * PUBLIC:    u_int32_t, db_pgno_t, u_int32_t, u_int32_t));
 */
int
__bam_ca_undodup(dbp, first, fpgno, fi, ti)
	DB *dbp;
	db_pgno_t fpgno;
	u_int32_t first, fi, ti;
{
	BTREE_CURSOR *orig_cp;
	DB *ldbp;
	DBC *dbc;
	DB_ENV *dbenv;
	int ret;

	dbenv = dbp->dbenv;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 */
	MUTEX_THREAD_LOCK(dbenv, dbenv->dblist_mutexp);
	for (ldbp = __dblist_get(dbenv, dbp->adj_fileid);
	    ldbp != NULL && ldbp->adj_fileid == dbp->adj_fileid;
	    ldbp = LIST_NEXT(ldbp, dblistlinks)) {
loop:		MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
		for (dbc = TAILQ_FIRST(&ldbp->active_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			orig_cp = (BTREE_CURSOR *)dbc->internal;

			/*
			 * A note on the orig_cp->opd != NULL requirement here:
			 * it's possible that there's a cursor that refers to
			 * the same duplicate set, but which has no opd cursor,
			 * because it refers to a different item and we took
			 * care of it while processing a previous record.
			 */
			if (orig_cp->pgno != fpgno ||
			    orig_cp->indx != first ||
			    orig_cp->opd == NULL ||
			    ((BTREE_CURSOR *)orig_cp->opd->internal)->indx
			    != ti)
				continue;
			MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
			if ((ret = __db_c_close(orig_cp->opd)) != 0)
				return (ret);
			orig_cp->opd = NULL;
			orig_cp->indx = fi;
			/*
			 * We released the mutex to free a cursor,
			 * start over.
			 */
			goto loop;
		}
		MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
	}
	MUTEX_THREAD_UNLOCK(dbenv, dbenv->dblist_mutexp);

	return (0);
}

/*
 * __bam_ca_rsplit --
 *	Adjust the cursors when doing reverse splits.
 *
 * PUBLIC: int __bam_ca_rsplit __P((DBC *, db_pgno_t, db_pgno_t));
 */
int
__bam_ca_rsplit(my_dbc, fpgno, tpgno)
	DBC* my_dbc;
	db_pgno_t fpgno, tpgno;
{
	DB *dbp, *ldbp;
	DBC *dbc;
	DB_ENV *dbenv;
	DB_LSN lsn;
	DB_TXN *my_txn;
	int found, ret;

	dbp = my_dbc->dbp;
	dbenv = dbp->dbenv;
	my_txn = IS_SUBTRANSACTION(my_dbc->txn) ? my_dbc->txn : NULL;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 */
	found = 0;
	MUTEX_THREAD_LOCK(dbenv, dbenv->dblist_mutexp);
	for (ldbp = __dblist_get(dbenv, dbp->adj_fileid);
	    ldbp != NULL && ldbp->adj_fileid == dbp->adj_fileid;
	    ldbp = LIST_NEXT(ldbp, dblistlinks)) {
		MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
		for (dbc = TAILQ_FIRST(&ldbp->active_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			if (dbc->dbtype == DB_RECNO)
				continue;
			if (dbc->internal->pgno == fpgno) {
				dbc->internal->pgno = tpgno;
				/* [#8032]
				DB_ASSERT(!STD_LOCKING(dbc) ||
				    dbc->internal->lock_mode != DB_LOCK_NG);
				*/
				if (my_txn != NULL && dbc->txn != my_txn)
					found = 1;
			}
		}
		MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
	}
	MUTEX_THREAD_UNLOCK(dbenv, dbenv->dblist_mutexp);

	if (found != 0 && DBC_LOGGING(my_dbc)) {
		if ((ret = __bam_curadj_log(dbp, my_dbc->txn,
		    &lsn, 0, DB_CA_RSPLIT, fpgno, tpgno, 0, 0, 0, 0)) != 0)
			return (ret);
	}
	return (0);
}

/*
 * __bam_ca_split --
 *	Adjust the cursors when splitting a page.
 *
 * PUBLIC: int __bam_ca_split __P((DBC *,
 * PUBLIC:    db_pgno_t, db_pgno_t, db_pgno_t, u_int32_t, int));
 */
int
__bam_ca_split(my_dbc, ppgno, lpgno, rpgno, split_indx, cleft)
	DBC *my_dbc;
	db_pgno_t ppgno, lpgno, rpgno;
	u_int32_t split_indx;
	int cleft;
{
	DB *dbp, *ldbp;
	DBC *dbc;
	DBC_INTERNAL *cp;
	DB_ENV *dbenv;
	DB_LSN lsn;
	DB_TXN *my_txn;
	int found, ret;

	dbp = my_dbc->dbp;
	dbenv = dbp->dbenv;
	my_txn = IS_SUBTRANSACTION(my_dbc->txn) ? my_dbc->txn : NULL;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 *
	 * If splitting the page that a cursor was on, the cursor has to be
	 * adjusted to point to the same record as before the split.  Most
	 * of the time we don't adjust pointers to the left page, because
	 * we're going to copy its contents back over the original page.  If
	 * the cursor is on the right page, it is decremented by the number of
	 * records split to the left page.
	 */
	found = 0;
	MUTEX_THREAD_LOCK(dbenv, dbenv->dblist_mutexp);
	for (ldbp = __dblist_get(dbenv, dbp->adj_fileid);
	    ldbp != NULL && ldbp->adj_fileid == dbp->adj_fileid;
	    ldbp = LIST_NEXT(ldbp, dblistlinks)) {
		MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
		for (dbc = TAILQ_FIRST(&ldbp->active_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			if (dbc->dbtype == DB_RECNO)
				continue;
			cp = dbc->internal;
			if (cp->pgno == ppgno) {
				/* [#8032]
				DB_ASSERT(!STD_LOCKING(dbc) ||
				    cp->lock_mode != DB_LOCK_NG);
				*/
				if (my_txn != NULL && dbc->txn != my_txn)
					found = 1;
				if (cp->indx < split_indx) {
					if (cleft)
						cp->pgno = lpgno;
				} else {
					cp->pgno = rpgno;
					cp->indx -= split_indx;
				}
			}
		}
		MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
	}
	MUTEX_THREAD_UNLOCK(dbenv, dbenv->dblist_mutexp);

	if (found != 0 && DBC_LOGGING(my_dbc)) {
		if ((ret = __bam_curadj_log(dbp,
		    my_dbc->txn, &lsn, 0, DB_CA_SPLIT, ppgno, rpgno,
		    cleft ? lpgno : PGNO_INVALID, 0, split_indx, 0)) != 0)
			return (ret);
	}

	return (0);
}

/*
 * __bam_ca_undosplit --
 *	Adjust the cursors when undoing a split of a page.
 *	If we grew a level we will execute this for both the
 *	left and the right pages.
 *	Called only during undo processing.
 *
 * PUBLIC: void __bam_ca_undosplit __P((DB *,
 * PUBLIC:    db_pgno_t, db_pgno_t, db_pgno_t, u_int32_t));
 */
void
__bam_ca_undosplit(dbp, frompgno, topgno, lpgno, split_indx)
	DB *dbp;
	db_pgno_t frompgno, topgno, lpgno;
	u_int32_t split_indx;
{
	DB *ldbp;
	DBC *dbc;
	DB_ENV *dbenv;
	DBC_INTERNAL *cp;

	dbenv = dbp->dbenv;

	/*
	 * Adjust the cursors.  See the comment in __bam_ca_delete().
	 *
	 * When backing out a split, we move the cursor back
	 * to the original offset and bump it by the split_indx.
	 */
	MUTEX_THREAD_LOCK(dbenv, dbenv->dblist_mutexp);
	for (ldbp = __dblist_get(dbenv, dbp->adj_fileid);
	    ldbp != NULL && ldbp->adj_fileid == dbp->adj_fileid;
	    ldbp = LIST_NEXT(ldbp, dblistlinks)) {
		MUTEX_THREAD_LOCK(dbenv, dbp->mutexp);
		for (dbc = TAILQ_FIRST(&ldbp->active_queue);
		    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
			if (dbc->dbtype == DB_RECNO)
				continue;
			cp = dbc->internal;
			if (cp->pgno == topgno) {
				cp->pgno = frompgno;
				cp->indx += split_indx;
			} else if (cp->pgno == lpgno)
				cp->pgno = frompgno;
		}
		MUTEX_THREAD_UNLOCK(dbenv, dbp->mutexp);
	}
	MUTEX_THREAD_UNLOCK(dbenv, dbenv->dblist_mutexp);
}