fs/zfs/dmu_object.c

/*
 * 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.
 * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
 * Copyright 2014 HybridCluster. All rights reserved.
 */

#include <sys/dmu.h>
#include <sys/dmu_objset.h>
#include <sys/dmu_tx.h>
#include <sys/dnode.h>
#include <sys/zap.h>
#include <sys/zfeature.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.
                     *
                     * Note that dmu_traverse depends on the behavior that we use
                     * multiple blocks of the dnode object before going back to
                     * reuse objects.  Any change to this algorithm should preserve
                     * that property or find another solution to the issues
                     * described in traverse_visitbp.
                     */
                    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 (SET_ERROR(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, dmu_tx_t *tx)
{
          dnode_t *dn;
          int err;

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

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

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

          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);
}

/*
 * Return (in *objectp) the next object which is allocated (or a hole)
 * after *object, taking into account only objects that may have been modified
 * after the specified txg.
 */
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);
}

/*
 * Turn this object from old_type into DMU_OTN_ZAP_METADATA, and bump the
 * refcount on SPA_FEATURE_EXTENSIBLE_DATASET.
 *
 * Only for use from syncing context, on MOS objects.
 */
void
dmu_object_zapify(objset_t *mos, uint64_t object, dmu_object_type_t old_type,
    dmu_tx_t *tx)
{
          dnode_t *dn;

          ASSERT(dmu_tx_is_syncing(tx));

          VERIFY0(dnode_hold(mos, object, FTAG, &dn));
          if (dn->dn_type == DMU_OTN_ZAP_METADATA) {
                    dnode_rele(dn, FTAG);
                    return;
          }
          ASSERT3U(dn->dn_type, ==, old_type);
          ASSERT0(dn->dn_maxblkid);
          dn->dn_next_type[tx->tx_txg & TXG_MASK] = dn->dn_type =
              DMU_OTN_ZAP_METADATA;
          dnode_setdirty(dn, tx);
          dnode_rele(dn, FTAG);

          mzap_create_impl(mos, object, 0, 0, tx);

          spa_feature_incr(dmu_objset_spa(mos),
              SPA_FEATURE_EXTENSIBLE_DATASET, tx);
}

void
dmu_object_free_zapified(objset_t *mos, uint64_t object, dmu_tx_t *tx)
{
          dnode_t *dn;
          dmu_object_type_t t;

          ASSERT(dmu_tx_is_syncing(tx));

          VERIFY0(dnode_hold(mos, object, FTAG, &dn));
          t = dn->dn_type;
          dnode_rele(dn, FTAG);

          if (t == DMU_OTN_ZAP_METADATA) {
                    spa_feature_decr(dmu_objset_spa(mos),
                        SPA_FEATURE_EXTENSIBLE_DATASET, tx);
          }
          VERIFY0(dmu_object_free(mos, object, tx));
}