fs/zfs/dmu_object.c

	dmu_object.c revision 2bf405a25eb25f79638fc951ff8d8857ad384417
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/dmu.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_tx.h>
#include <sys/dnode.h>

uint64_t
dmu_object_alloc(objset_t *os, dmu_object_type_t ot, int blocksize,
    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
    objset_impl_t *osi = os->os;
    uint64_t object;
    uint64_t L2_dnode_count = DNODES_PER_BLOCK <<
        (osi->os_meta_dnode->dn_indblkshift - SPA_BLKPTRSHIFT);
    dnode_t *dn = NULL;
    int restarted = B_FALSE;

    mutex_enter(&osi->os_obj_lock);
    for (;;) {
        object = osi->os_obj_next;
        /*
         * Each time we polish off an L2 bp worth of dnodes
         * (2^13 objects), move to another L2 bp that's still
         * reasonably sparse (at most 1/4 full).  Look from the
         * beginning once, but after that keep looking from here.
         * If we can't find one, just keep going from here.
         */
        if (P2PHASE(object, L2_dnode_count) == 0) {
            uint64_t offset = restarted ? object << DNODE_SHIFT : 0;
            int error = dnode_next_offset(osi->os_meta_dnode,
                DNODE_FIND_HOLE,
                &offset, 2, DNODES_PER_BLOCK >> 2, 0);
            restarted = B_TRUE;
            if (error == 0)
                object = offset >> DNODE_SHIFT;
        }
        osi->os_obj_next = ++object;

        /*
         * XXX We should check for an i/o error here and return
         * up to our caller.  Actually we should pre-read it in
         * dmu_tx_assign(), but there is currently no mechanism
         * to do so.
         */
        (void) dnode_hold_impl(os->os, object, DNODE_MUST_BE_FREE,
            FTAG, &dn);
        if (dn)
            break;

        if (dmu_object_next(os, &object, B_TRUE, 0) == 0)
            osi->os_obj_next = object - 1;
    }

    dnode_allocate(dn, ot, blocksize, 0, bonustype, bonuslen, tx);
    dnode_rele(dn, FTAG);

    mutex_exit(&osi->os_obj_lock);

    dmu_tx_add_new_object(tx, os, object);
    return (object);
}

int
dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
    int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
{
    dnode_t *dn;
    int err;

    if (object == DMU_META_DNODE_OBJECT && !dmu_tx_private_ok(tx))
        return (EBADF);

    err = dnode_hold_impl(os->os, object, DNODE_MUST_BE_FREE, FTAG, &dn);
    if (err)
        return (err);
    dnode_allocate(dn, ot, blocksize, 0, bonustype, bonuslen, tx);
    dnode_rele(dn, FTAG);

    dmu_tx_add_new_object(tx, os, object);
    return (0);
}

int
dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
    int blocksize, dmu_object_type_t bonustype, int bonuslen)
{
    dnode_t *dn;
    dmu_tx_t *tx;
    int nblkptr;
    int err;

    if (object == DMU_META_DNODE_OBJECT)
        return (EBADF);

    err = dnode_hold_impl(os->os, object, DNODE_MUST_BE_ALLOCATED,
        FTAG, &dn);
    if (err)
        return (err);

    if (dn->dn_type == ot && dn->dn_datablksz == blocksize &&
        dn->dn_bonustype == bonustype && dn->dn_bonuslen == bonuslen) {
        /* nothing is changing, this is a noop */
        dnode_rele(dn, FTAG);
        return (0);
    }

    tx = dmu_tx_create(os);
    dmu_tx_hold_bonus(tx, object);
    err = dmu_tx_assign(tx, TXG_WAIT);
    if (err) {
        dmu_tx_abort(tx);
        dnode_rele(dn, FTAG);
        return (err);
    }

    nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);

    /*
     * If we are losing blkptrs or changing the block size this must
     * be a new file instance.   We must clear out the previous file
     * contents before we can change this type of metadata in the dnode.
     */
    if (dn->dn_nblkptr > nblkptr || dn->dn_datablksz != blocksize)
        dmu_free_long_range(os, object, 0, DMU_OBJECT_END);

    dnode_reallocate(dn, ot, blocksize, bonustype, bonuslen, tx);

    dmu_tx_commit(tx);

    dnode_rele(dn, FTAG);

    return (0);
}

int
dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx)
{
    dnode_t *dn;
    int err;

    ASSERT(object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx));

    err = dnode_hold_impl(os->os, object, DNODE_MUST_BE_ALLOCATED,
        FTAG, &dn);
    if (err)
        return (err);

    ASSERT(dn->dn_type != DMU_OT_NONE);
    dnode_free_range(dn, 0, DMU_OBJECT_END, tx);
    dnode_free(dn, tx);
    dnode_rele(dn, FTAG);

    return (0);
}

int
dmu_object_next(objset_t *os, uint64_t *objectp, boolean_t hole, uint64_t txg)
{
    uint64_t offset = (*objectp + 1) << DNODE_SHIFT;
    int error;

    error = dnode_next_offset(os->os->os_meta_dnode,
        (hole ? DNODE_FIND_HOLE : 0), &offset, 0, DNODES_PER_BLOCK, txg);

    *objectp = offset >> DNODE_SHIFT;

    return (error);
}