dmu_object.c

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/*
 * 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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#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)
{
        uint64_t object;
        uint64_t L2_dnode_count = DNODES_PER_BLOCK <<
            (DMU_META_DNODE(os)->dn_indblkshift - SPA_BLKPTRSHIFT);
        dnode_t *dn = NULL;
        int restarted = B_FALSE;

        mutex_enter(&os->os_obj_lock);
        for (;;) {
                object = os->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(DMU_META_DNODE(os),
                            DNODE_FIND_HOLE,
                            &offset, 2, DNODES_PER_BLOCK >> 2, 0);
                        restarted = B_TRUE;
                        if (error == 0)
                                object = offset >> DNODE_SHIFT;
                }
                os->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, object, DNODE_MUST_BE_FREE,
                    FTAG, &dn);
                if (dn)
                        break;

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

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

        mutex_exit(&os->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, 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, 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);
        }

        if (bonustype == DMU_OT_SA) {
                nblkptr = 1;
        } else {
                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) {
                err = dmu_free_long_range(os, object, 0, DMU_OBJECT_END);
                if (err)
                        goto out;
        }

        tx = dmu_tx_create(os);
        dmu_tx_hold_bonus(tx, object);
        err = dmu_tx_assign(tx, TXG_WAIT);
        if (err) {
                dmu_tx_abort(tx);
                goto out;
        }

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

        dmu_tx_commit(tx);
out:
        dnode_rele(dn, FTAG);

        return (err);
}

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, 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(DMU_META_DNODE(os),
            (hole ? DNODE_FIND_HOLE : 0), &offset, 0, DNODES_PER_BLOCK, txg);

        *objectp = offset >> DNODE_SHIFT;

        return (error);
}