fs/zfs/dsl_pool.c

	dsl_pool.c revision 99653d4ee642c6528e88224f12409a5f23060994
/*
 * 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 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/dsl_pool.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/arc.h>
#include <sys/zap.h>
#include <sys/zfs_context.h>
#include <sys/fs/zfs.h>

/* internal reserved dir name */
#define MOS_DIR_NAME "$MOS"

static int
dsl_pool_open_mos_dir(dsl_pool_t *dp, dsl_dir_t **ddp)
{
    uint64_t obj;
    int err;

    err = zap_lookup(dp->dp_meta_objset,
        dp->dp_root_dir->dd_phys->dd_child_dir_zapobj,
        MOS_DIR_NAME, sizeof (obj), 1, &obj);
    if (err)
        return (err);

    return (dsl_dir_open_obj(dp, obj, MOS_DIR_NAME, dp, ddp));
}

static dsl_pool_t *
dsl_pool_open_impl(spa_t *spa, uint64_t txg)
{
    dsl_pool_t *dp;
    blkptr_t *bp = spa_get_rootblkptr(spa);

    dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
    dp->dp_spa = spa;
    dp->dp_meta_rootbp = *bp;
    txg_init(dp, txg);

    txg_list_create(&dp->dp_dirty_datasets,
        offsetof(dsl_dataset_t, ds_dirty_link));
    txg_list_create(&dp->dp_dirty_dirs,
        offsetof(dsl_dir_t, dd_dirty_link));
    list_create(&dp->dp_synced_objsets, sizeof (dsl_dataset_t),
        offsetof(dsl_dataset_t, ds_synced_link));

    return (dp);
}

int
dsl_pool_open(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
{
    int err;
    dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
    objset_impl_t *osi;

    rw_enter(&dp->dp_config_rwlock, RW_READER);
    err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp, &osi);
    if (err)
        goto out;
    dp->dp_meta_objset = &osi->os;

    err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
        DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
        &dp->dp_root_dir_obj);
    if (err)
        goto out;

    err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
        NULL, dp, &dp->dp_root_dir);
    if (err)
        goto out;

    err = dsl_pool_open_mos_dir(dp, &dp->dp_mos_dir);
    if (err)
        goto out;

out:
    rw_exit(&dp->dp_config_rwlock);
    if (err)
        dsl_pool_close(dp);
    else
        *dpp = dp;

    return (err);
}

void
dsl_pool_close(dsl_pool_t *dp)
{
    /* drop our reference from dsl_pool_open() */
    if (dp->dp_mos_dir)
        dsl_dir_close(dp->dp_mos_dir, dp);
    if (dp->dp_root_dir)
        dsl_dir_close(dp->dp_root_dir, dp);

    /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
    if (dp->dp_meta_objset)
        dmu_objset_evict(NULL, dp->dp_meta_objset->os);

    txg_list_destroy(&dp->dp_dirty_datasets);
    txg_list_destroy(&dp->dp_dirty_dirs);
    list_destroy(&dp->dp_synced_objsets);

    arc_flush();
    txg_fini(dp);
    kmem_free(dp, sizeof (dsl_pool_t));
}

dsl_pool_t *
dsl_pool_create(spa_t *spa, uint64_t txg)
{
    int err;
    dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
    dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
    dp->dp_meta_objset = &dmu_objset_create_impl(spa,
        NULL, DMU_OST_META, tx)->os;

    /* create the pool directory */
    err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
        DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
    ASSERT3U(err, ==, 0);

    /* create and open the root dir */
    dsl_dataset_create_root(dp, &dp->dp_root_dir_obj, tx);
    VERIFY(0 == dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
        NULL, dp, &dp->dp_root_dir));

    /* create and open the meta-objset dir */
    VERIFY(0 == dsl_dir_create_sync(dp->dp_root_dir, MOS_DIR_NAME, tx));
    ASSERT3U(err, ==, 0);
    VERIFY(0 == dsl_pool_open_mos_dir(dp, &dp->dp_mos_dir));

    dmu_tx_commit(tx);

    return (dp);
}

void
dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
{
    dmu_tx_t *tx;
    objset_impl_t *mosi = dp->dp_meta_objset->os;

    tx = dmu_tx_create_assigned(dp, txg);

    do {
        dsl_dir_t *dd;
        dsl_dataset_t *ds;

        while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {
            if (!list_link_active(&ds->ds_synced_link))
                list_insert_tail(&dp->dp_synced_objsets, ds);
            dsl_dataset_sync(ds, tx);
        }
        while (dd = txg_list_remove(&dp->dp_dirty_dirs, txg))
            dsl_dir_sync(dd, tx);
        /*
         * We need to loop since dsl_dir_sync() could create a
         * new (dirty) objset.
         * XXX - isn't this taken care of by the spa's sync to
         * convergence loop?
         */
    } while (!txg_list_empty(&dp->dp_dirty_datasets, txg));

    if (list_head(&mosi->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||
        list_head(&mosi->os_free_dnodes[txg & TXG_MASK]) != NULL) {
        dmu_objset_sync(mosi, tx);
        dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
        spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
    }

    dmu_tx_commit(tx);
}

void
dsl_pool_zil_clean(dsl_pool_t *dp)
{
    dsl_dataset_t *ds;

    while (ds = list_head(&dp->dp_synced_objsets)) {
        list_remove(&dp->dp_synced_objsets, ds);
        ASSERT(ds->ds_user_ptr != NULL);
        zil_clean(((objset_impl_t *)ds->ds_user_ptr)->os_zil);
    }
}

int
dsl_pool_sync_context(dsl_pool_t *dp)
{
    /*
     * Yeah, this is cheesy.  But the SPA needs some way to let
     * the sync threads invoke spa_open() and spa_close() while
     * it holds the namespace lock.  I'm certainly open to better
     * ideas for how to determine whether the current thread is
     * operating on behalf of spa_sync().  This works for now.
     */
    return (curthread == dp->dp_tx.tx_sync_thread ||
        BP_IS_HOLE(&dp->dp_meta_rootbp));
}

uint64_t
dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree)
{
    uint64_t space, resv;

    /*
     * Reserve about 1.6% (1/64), or at least 32MB, for allocation
     * efficiency.
     * XXX The intent log is not accounted for, so it must fit
     * within this slop.
     *
     * If we're trying to assess whether it's OK to do a free,
     * cut the reservation in half to allow forward progress
     * (e.g. make it possible to rm(1) files from a full pool).
     */
    space = spa_get_dspace(dp->dp_spa);
    resv = MAX(space >> 6, SPA_MINDEVSIZE >> 1);
    if (netfree)
        resv >>= 1;

    return (space - resv);
}