/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998
 *      Sleepycat Software.  All rights reserved.
 */
#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)mp_fput.c     10.24 (Sleepycat) 9/27/98";
#endif /* not lint */

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

#include <errno.h>
#endif

#include "db_int.h"
#include "shqueue.h"
#include "db_shash.h"
#include "mp.h"
#include "common_ext.h"

/*
 * memp_fput --
 *      Mpool file put function.
 */
int
memp_fput(dbmfp, pgaddr, flags)
        DB_MPOOLFILE *dbmfp;
        void *pgaddr;
        u_int32_t flags;
{
        BH *bhp;
        DB_MPOOL *dbmp;
        MPOOL *mp;
        int wrote, ret;

        dbmp = dbmfp->dbmp;
        mp = dbmp->mp;

        MP_PANIC_CHECK(dbmp);

        /* Validate arguments. */
        if (flags) {
                if ((ret = __db_fchk(dbmp->dbenv, "memp_fput", flags,
                    DB_MPOOL_CLEAN | DB_MPOOL_DIRTY | DB_MPOOL_DISCARD)) != 0)
                        return (ret);
                if ((ret = __db_fcchk(dbmp->dbenv, "memp_fput",
                    flags, DB_MPOOL_CLEAN, DB_MPOOL_DIRTY)) != 0)
                        return (ret);

                if (LF_ISSET(DB_MPOOL_DIRTY) && F_ISSET(dbmfp, MP_READONLY)) {
                        __db_err(dbmp->dbenv,
                            "%s: dirty flag set for readonly file page",
                            __memp_fn(dbmfp));
                        return (EACCES);
                }
        }

        LOCKREGION(dbmp);

        /* Decrement the pinned reference count. */
        if (dbmfp->pinref == 0)
                __db_err(dbmp->dbenv,
                    "%s: put: more blocks returned than retrieved",
                    __memp_fn(dbmfp));
        else
                --dbmfp->pinref;

        /*
         * If we're mapping the file, there's nothing to do.  Because we can
         * stop mapping the file at any time, we have to check on each buffer
         * to see if the address we gave the application was part of the map
         * region.
         */
        if (dbmfp->addr != NULL && pgaddr >= dbmfp->addr &&
            (u_int8_t *)pgaddr <= (u_int8_t *)dbmfp->addr + dbmfp->len) {
                UNLOCKREGION(dbmp);
                return (0);
        }

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

        /* Set/clear the page bits. */
        if (LF_ISSET(DB_MPOOL_CLEAN) && F_ISSET(bhp, BH_DIRTY)) {
                ++mp->stat.st_page_clean;
                --mp->stat.st_page_dirty;
                F_CLR(bhp, BH_DIRTY);
        }
        if (LF_ISSET(DB_MPOOL_DIRTY) && !F_ISSET(bhp, BH_DIRTY)) {
                --mp->stat.st_page_clean;
                ++mp->stat.st_page_dirty;
                F_SET(bhp, BH_DIRTY);
        }
        if (LF_ISSET(DB_MPOOL_DISCARD))
                F_SET(bhp, BH_DISCARD);

        /*
         * Check for a reference count going to zero.  This can happen if the
         * application returns a page twice.
         */
        if (bhp->ref == 0) {
                __db_err(dbmp->dbenv, "%s: page %lu: unpinned page returned",
                    __memp_fn(dbmfp), (u_long)bhp->pgno);
                UNLOCKREGION(dbmp);
                return (EINVAL);
        }

        /*
         * If more than one reference to the page, we're done.  Ignore the
         * discard flags (for now) and leave it at its position in the LRU
         * chain.  The rest gets done at last reference close.
         */
        if (--bhp->ref > 0) {
                UNLOCKREGION(dbmp);
                return (0);
        }

        /* Move the buffer to the head/tail of the LRU chain. */
        SH_TAILQ_REMOVE(&mp->bhq, bhp, q, __bh);
        if (F_ISSET(bhp, BH_DISCARD))
                SH_TAILQ_INSERT_HEAD(&mp->bhq, bhp, q, __bh);
        else
                SH_TAILQ_INSERT_TAIL(&mp->bhq, bhp, q);

        /*
         * If this buffer is scheduled for writing because of a checkpoint, we
         * need to write it (if we marked it dirty), or update the checkpoint
         * counters (if we didn't mark it dirty).  If we try to write it and
         * can't, that's not necessarily an error, but set a flag so that the
         * next time the memp_sync function runs we try writing it there, as
         * the checkpoint application better be able to write all of the files.
         */
        if (F_ISSET(bhp, BH_WRITE))
                if (F_ISSET(bhp, BH_DIRTY)) {
                        if (__memp_bhwrite(dbmp,
                            dbmfp->mfp, bhp, NULL, &wrote) != 0 || !wrote)
                                F_SET(mp, MP_LSN_RETRY);
                } else {
                        F_CLR(bhp, BH_WRITE);

                        --dbmfp->mfp->lsn_cnt;
                        --mp->lsn_cnt;
                }

        UNLOCKREGION(dbmp);
        return (0);
}