db/mp/mp_fput.c

/*-
 * 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);
}