/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 2012 Oracle and/or its affiliates.  All rights reserved.
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 * $Id$
 */

#include "db_config.h"

#include "db_int.h"
#include "dbinc/log.h"
#include "dbinc/mp.h"
#include "dbinc/txn.h"

/*
 * __memp_dirty --
 *	Upgrade a page from a read-only to a writable pointer.
 *
 * PUBLIC: int __memp_dirty __P((DB_MPOOLFILE *, void *,
 * PUBLIC:     DB_THREAD_INFO *, DB_TXN *, DB_CACHE_PRIORITY, u_int32_t));
 */
int
__memp_dirty(dbmfp, addrp, ip, txn, priority, flags)
	DB_MPOOLFILE *dbmfp;
	void *addrp;
	DB_THREAD_INFO *ip;
	DB_TXN *txn;
	DB_CACHE_PRIORITY priority;
	u_int32_t flags;
{
	BH *bhp;
	DB_MPOOL *dbmp;
	DB_MPOOL_HASH *hp;
	ENV *env;
	MPOOL *c_mp;
	REGINFO *infop;
	db_pgno_t pgno;
	void *pgaddr;

	env = dbmfp->env;
	dbmp = env->mp_handle;

	/* Convert the page address to a buffer header. */
	pgaddr = *(void **)addrp;
	bhp = (BH *)((u_int8_t *)pgaddr - SSZA(BH, buf));
	pgno = bhp->pgno;

	/* If we have it exclusively then its already dirty. */
	if (F_ISSET(bhp, BH_EXCLUSIVE)) {
		DB_ASSERT(env, F_ISSET(bhp, BH_DIRTY));
		return (0);
	}

	if (flags == 0)
		flags = DB_MPOOL_DIRTY;
	DB_ASSERT(env, flags == DB_MPOOL_DIRTY || flags == DB_MPOOL_EDIT);

	if (F_ISSET(dbmfp, MP_READONLY)) {
		__db_errx(env, DB_STR_A("3008",
		    "%s: dirty flag set for readonly file page", "%s"),
		    __memp_fn(dbmfp));
		return (EACCES);
	}

	infop = &dbmp->reginfo[bhp->region];
	c_mp = infop->primary;
	hp = R_ADDR(infop, c_mp->htab);
	hp = &hp[bhp->bucket];

	/* Drop the shared latch and get an exclusive. We have the buf ref'ed.*/
	MUTEX_UNLOCK(env, bhp->mtx_buf);
	MUTEX_LOCK(env, bhp->mtx_buf);
	DB_ASSERT(env, !F_ISSET(bhp, BH_EXCLUSIVE));
	F_SET(bhp, BH_EXCLUSIVE);

	/* Set/clear the page bits. */
	if (!F_ISSET(bhp, BH_DIRTY)) {
#ifdef DIAGNOSTIC
		MUTEX_LOCK(env, hp->mtx_hash);
#endif
		atomic_inc(env, &hp->hash_page_dirty);
		F_SET(bhp, BH_DIRTY);
#ifdef DIAGNOSTIC
		MUTEX_UNLOCK(env, hp->mtx_hash);
#endif
	}

	DB_ASSERT(env, !F_ISSET(bhp, BH_DIRTY) ||
	    atomic_read(&hp->hash_page_dirty) != 0);
	COMPQUIET(ip, NULL);
	COMPQUIET(txn, NULL);
	COMPQUIET(priority, 0);
	return (0);
}

/*
 * __memp_shared --
 *	Downgrade a page from exlusively held to shared.
 *
 * PUBLIC: int __memp_shared __P((DB_MPOOLFILE *, void *));
 */
int
__memp_shared(dbmfp, pgaddr)
	DB_MPOOLFILE *dbmfp;
	void *pgaddr;
{
	BH *bhp;
	ENV *env;

	env = dbmfp->env;
	/* Convert the page address to a buffer header. */
	bhp = (BH *)((u_int8_t *)pgaddr - SSZA(BH, buf));

	if (F_ISSET(bhp, BH_DIRTY))
		dbmfp->mfp->file_written = 1;
	DB_ASSERT(env, F_ISSET(bhp, BH_EXCLUSIVE));
	F_CLR(bhp, BH_EXCLUSIVE);
	MUTEX_UNLOCK(env, bhp->mtx_buf);
	MUTEX_READLOCK(env, bhp->mtx_buf);

	return (0);
}