/*
 * 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) 2011, 2016 by Delphix. All rights reserved.
 * Copyright (c) 2014 Integros [integros.com]
 * Copyright (c) 2017 Datto Inc.
 */

#include <sys/bpobj.h>
#include <sys/zfs_context.h>
#include <sys/refcount.h>
#include <sys/dsl_pool.h>
#include <sys/zfeature.h>
#include <sys/zap.h>

/*
 * Return an empty bpobj, preferably the empty dummy one (dp_empty_bpobj).
 */
uint64_t
bpobj_alloc_empty(objset_t *os, int blocksize, dmu_tx_t *tx)
{
        spa_t *spa = dmu_objset_spa(os);
        dsl_pool_t *dp = dmu_objset_pool(os);

        if (spa_feature_is_enabled(spa, SPA_FEATURE_EMPTY_BPOBJ)) {
                if (!spa_feature_is_active(spa, SPA_FEATURE_EMPTY_BPOBJ)) {
                        ASSERT0(dp->dp_empty_bpobj);
                        dp->dp_empty_bpobj =
                            bpobj_alloc(os, SPA_OLD_MAXBLOCKSIZE, tx);
                        VERIFY(zap_add(os,
                            DMU_POOL_DIRECTORY_OBJECT,
                            DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
                            &dp->dp_empty_bpobj, tx) == 0);
                }
                spa_feature_incr(spa, SPA_FEATURE_EMPTY_BPOBJ, tx);
                ASSERT(dp->dp_empty_bpobj != 0);
                return (dp->dp_empty_bpobj);
        } else {
                return (bpobj_alloc(os, blocksize, tx));
        }
}

void
bpobj_decr_empty(objset_t *os, dmu_tx_t *tx)
{
        dsl_pool_t *dp = dmu_objset_pool(os);

        spa_feature_decr(dmu_objset_spa(os), SPA_FEATURE_EMPTY_BPOBJ, tx);
        if (!spa_feature_is_active(dmu_objset_spa(os),
            SPA_FEATURE_EMPTY_BPOBJ)) {
                VERIFY3U(0, ==, zap_remove(dp->dp_meta_objset,
                    DMU_POOL_DIRECTORY_OBJECT,
                    DMU_POOL_EMPTY_BPOBJ, tx));
                VERIFY3U(0, ==, dmu_object_free(os, dp->dp_empty_bpobj, tx));
                dp->dp_empty_bpobj = 0;
        }
}

uint64_t
bpobj_alloc(objset_t *os, int blocksize, dmu_tx_t *tx)
{
        int size;

        if (spa_version(dmu_objset_spa(os)) < SPA_VERSION_BPOBJ_ACCOUNT)
                size = BPOBJ_SIZE_V0;
        else if (spa_version(dmu_objset_spa(os)) < SPA_VERSION_DEADLISTS)
                size = BPOBJ_SIZE_V1;
        else
                size = sizeof (bpobj_phys_t);

        return (dmu_object_alloc(os, DMU_OT_BPOBJ, blocksize,
            DMU_OT_BPOBJ_HDR, size, tx));
}

void
bpobj_free(objset_t *os, uint64_t obj, dmu_tx_t *tx)
{
        int64_t i;
        bpobj_t bpo;
        dmu_object_info_t doi;
        int epb;
        dmu_buf_t *dbuf = NULL;

        ASSERT(obj != dmu_objset_pool(os)->dp_empty_bpobj);
        VERIFY3U(0, ==, bpobj_open(&bpo, os, obj));

        mutex_enter(&bpo.bpo_lock);

        if (!bpo.bpo_havesubobj || bpo.bpo_phys->bpo_subobjs == 0)
                goto out;

        VERIFY3U(0, ==, dmu_object_info(os, bpo.bpo_phys->bpo_subobjs, &doi));
        epb = doi.doi_data_block_size / sizeof (uint64_t);

        for (i = bpo.bpo_phys->bpo_num_subobjs - 1; i >= 0; i--) {
                uint64_t *objarray;
                uint64_t offset, blkoff;

                offset = i * sizeof (uint64_t);
                blkoff = P2PHASE(i, epb);

                if (dbuf == NULL || dbuf->db_offset > offset) {
                        if (dbuf)
                                dmu_buf_rele(dbuf, FTAG);
                        VERIFY3U(0, ==, dmu_buf_hold(os,
                            bpo.bpo_phys->bpo_subobjs, offset, FTAG, &dbuf, 0));
                }

                ASSERT3U(offset, >=, dbuf->db_offset);
                ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);

                objarray = dbuf->db_data;
                bpobj_free(os, objarray[blkoff], tx);
        }
        if (dbuf) {
                dmu_buf_rele(dbuf, FTAG);
                dbuf = NULL;
        }
        VERIFY3U(0, ==, dmu_object_free(os, bpo.bpo_phys->bpo_subobjs, tx));

out:
        mutex_exit(&bpo.bpo_lock);
        bpobj_close(&bpo);

        VERIFY3U(0, ==, dmu_object_free(os, obj, tx));
}

int
bpobj_open(bpobj_t *bpo, objset_t *os, uint64_t object)
{
        dmu_object_info_t doi;
        int err;

        err = dmu_object_info(os, object, &doi);
        if (err)
                return (err);

        bzero(bpo, sizeof (*bpo));
        mutex_init(&bpo->bpo_lock, NULL, MUTEX_DEFAULT, NULL);

        ASSERT(bpo->bpo_dbuf == NULL);
        ASSERT(bpo->bpo_phys == NULL);
        ASSERT(object != 0);
        ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ);
        ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_BPOBJ_HDR);

        err = dmu_bonus_hold(os, object, bpo, &bpo->bpo_dbuf);
        if (err)
                return (err);

        bpo->bpo_os = os;
        bpo->bpo_object = object;
        bpo->bpo_epb = doi.doi_data_block_size >> SPA_BLKPTRSHIFT;
        bpo->bpo_havecomp = (doi.doi_bonus_size > BPOBJ_SIZE_V0);
        bpo->bpo_havesubobj = (doi.doi_bonus_size > BPOBJ_SIZE_V1);
        bpo->bpo_phys = bpo->bpo_dbuf->db_data;
        return (0);
}

boolean_t
bpobj_is_open(const bpobj_t *bpo)
{
        return (bpo->bpo_object != 0);
}

void
bpobj_close(bpobj_t *bpo)
{
        /* Lame workaround for closing a bpobj that was never opened. */
        if (bpo->bpo_object == 0)
                return;

        dmu_buf_rele(bpo->bpo_dbuf, bpo);
        if (bpo->bpo_cached_dbuf != NULL)
                dmu_buf_rele(bpo->bpo_cached_dbuf, bpo);
        bpo->bpo_dbuf = NULL;
        bpo->bpo_phys = NULL;
        bpo->bpo_cached_dbuf = NULL;
        bpo->bpo_object = 0;

        mutex_destroy(&bpo->bpo_lock);
}

boolean_t
bpobj_is_empty(bpobj_t *bpo)
{
        return (bpo->bpo_phys->bpo_num_blkptrs == 0 &&
            (!bpo->bpo_havesubobj || bpo->bpo_phys->bpo_num_subobjs == 0));
}

static int
bpobj_iterate_impl(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx,
    boolean_t free)
{
        dmu_object_info_t doi;
        int epb;
        int64_t i;
        int err = 0;
        dmu_buf_t *dbuf = NULL;

        ASSERT(bpobj_is_open(bpo));
        mutex_enter(&bpo->bpo_lock);

        if (free)
                dmu_buf_will_dirty(bpo->bpo_dbuf, tx);

        for (i = bpo->bpo_phys->bpo_num_blkptrs - 1; i >= 0; i--) {
                blkptr_t *bparray;
                blkptr_t *bp;
                uint64_t offset, blkoff;

                offset = i * sizeof (blkptr_t);
                blkoff = P2PHASE(i, bpo->bpo_epb);

                if (dbuf == NULL || dbuf->db_offset > offset) {
                        if (dbuf)
                                dmu_buf_rele(dbuf, FTAG);
                        err = dmu_buf_hold(bpo->bpo_os, bpo->bpo_object, offset,
                            FTAG, &dbuf, 0);
                        if (err)
                                break;
                }

                ASSERT3U(offset, >=, dbuf->db_offset);
                ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);

                bparray = dbuf->db_data;
                bp = &bparray[blkoff];
                err = func(arg, bp, tx);
                if (err)
                        break;
                if (free) {
                        bpo->bpo_phys->bpo_bytes -=
                            bp_get_dsize_sync(dmu_objset_spa(bpo->bpo_os), bp);
                        ASSERT3S(bpo->bpo_phys->bpo_bytes, >=, 0);
                        if (bpo->bpo_havecomp) {
                                bpo->bpo_phys->bpo_comp -= BP_GET_PSIZE(bp);
                                bpo->bpo_phys->bpo_uncomp -= BP_GET_UCSIZE(bp);
                        }
                        bpo->bpo_phys->bpo_num_blkptrs--;
                        ASSERT3S(bpo->bpo_phys->bpo_num_blkptrs, >=, 0);
                }
        }
        if (dbuf) {
                dmu_buf_rele(dbuf, FTAG);
                dbuf = NULL;
        }
        if (free) {
                VERIFY3U(0, ==, dmu_free_range(bpo->bpo_os, bpo->bpo_object,
                    (i + 1) * sizeof (blkptr_t), DMU_OBJECT_END, tx));
        }
        if (err || !bpo->bpo_havesubobj || bpo->bpo_phys->bpo_subobjs == 0)
                goto out;

        ASSERT(bpo->bpo_havecomp);
        err = dmu_object_info(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, &doi);
        if (err) {
                mutex_exit(&bpo->bpo_lock);
                return (err);
        }
        ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ_SUBOBJ);
        epb = doi.doi_data_block_size / sizeof (uint64_t);

        for (i = bpo->bpo_phys->bpo_num_subobjs - 1; i >= 0; i--) {
                uint64_t *objarray;
                uint64_t offset, blkoff;
                bpobj_t sublist;
                uint64_t used_before, comp_before, uncomp_before;
                uint64_t used_after, comp_after, uncomp_after;

                offset = i * sizeof (uint64_t);
                blkoff = P2PHASE(i, epb);

                if (dbuf == NULL || dbuf->db_offset > offset) {
                        if (dbuf)
                                dmu_buf_rele(dbuf, FTAG);
                        err = dmu_buf_hold(bpo->bpo_os,
                            bpo->bpo_phys->bpo_subobjs, offset, FTAG, &dbuf, 0);
                        if (err)
                                break;
                }

                ASSERT3U(offset, >=, dbuf->db_offset);
                ASSERT3U(offset, <, dbuf->db_offset + dbuf->db_size);

                objarray = dbuf->db_data;
                err = bpobj_open(&sublist, bpo->bpo_os, objarray[blkoff]);
                if (err)
                        break;
                if (free) {
                        err = bpobj_space(&sublist,
                            &used_before, &comp_before, &uncomp_before);
                        if (err != 0) {
                                bpobj_close(&sublist);
                                break;
                        }
                }
                err = bpobj_iterate_impl(&sublist, func, arg, tx, free);
                if (free) {
                        VERIFY3U(0, ==, bpobj_space(&sublist,
                            &used_after, &comp_after, &uncomp_after));
                        bpo->bpo_phys->bpo_bytes -= used_before - used_after;
                        ASSERT3S(bpo->bpo_phys->bpo_bytes, >=, 0);
                        bpo->bpo_phys->bpo_comp -= comp_before - comp_after;
                        bpo->bpo_phys->bpo_uncomp -=
                            uncomp_before - uncomp_after;
                }

                bpobj_close(&sublist);
                if (err)
                        break;
                if (free) {
                        err = dmu_object_free(bpo->bpo_os,
                            objarray[blkoff], tx);
                        if (err)
                                break;
                        bpo->bpo_phys->bpo_num_subobjs--;
                        ASSERT3S(bpo->bpo_phys->bpo_num_subobjs, >=, 0);
                }
        }
        if (dbuf) {
                dmu_buf_rele(dbuf, FTAG);
                dbuf = NULL;
        }
        if (free) {
                VERIFY3U(0, ==, dmu_free_range(bpo->bpo_os,
                    bpo->bpo_phys->bpo_subobjs,
                    (i + 1) * sizeof (uint64_t), DMU_OBJECT_END, tx));
        }

out:
        /* If there are no entries, there should be no bytes. */
        if (bpobj_is_empty(bpo)) {
                ASSERT0(bpo->bpo_phys->bpo_bytes);
                ASSERT0(bpo->bpo_phys->bpo_comp);
                ASSERT0(bpo->bpo_phys->bpo_uncomp);
        }

        mutex_exit(&bpo->bpo_lock);
        return (err);
}

/*
 * Iterate and remove the entries.  If func returns nonzero, iteration
 * will stop and that entry will not be removed.
 */
int
bpobj_iterate(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx)
{
        return (bpobj_iterate_impl(bpo, func, arg, tx, B_TRUE));
}

/*
 * Iterate the entries.  If func returns nonzero, iteration will stop.
 */
int
bpobj_iterate_nofree(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx)
{
        return (bpobj_iterate_impl(bpo, func, arg, tx, B_FALSE));
}

void
bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dmu_tx_t *tx)
{
        bpobj_t subbpo;
        uint64_t used, comp, uncomp, subsubobjs;

        ASSERT(bpobj_is_open(bpo));
        ASSERT(subobj != 0);
        ASSERT(bpo->bpo_havesubobj);
        ASSERT(bpo->bpo_havecomp);
        ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);

        if (subobj == dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj) {
                bpobj_decr_empty(bpo->bpo_os, tx);
                return;
        }

        VERIFY3U(0, ==, bpobj_open(&subbpo, bpo->bpo_os, subobj));
        VERIFY3U(0, ==, bpobj_space(&subbpo, &used, &comp, &uncomp));

        if (bpobj_is_empty(&subbpo)) {
                /* No point in having an empty subobj. */
                bpobj_close(&subbpo);
                bpobj_free(bpo->bpo_os, subobj, tx);
                return;
        }

        mutex_enter(&bpo->bpo_lock);
        dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
        if (bpo->bpo_phys->bpo_subobjs == 0) {
                bpo->bpo_phys->bpo_subobjs = dmu_object_alloc(bpo->bpo_os,
                    DMU_OT_BPOBJ_SUBOBJ, SPA_OLD_MAXBLOCKSIZE,
                    DMU_OT_NONE, 0, tx);
        }

        dmu_object_info_t doi;
        ASSERT0(dmu_object_info(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, &doi));
        ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ_SUBOBJ);

        dmu_write(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs,
            bpo->bpo_phys->bpo_num_subobjs * sizeof (subobj),
            sizeof (subobj), &subobj, tx);
        bpo->bpo_phys->bpo_num_subobjs++;

        /*
         * If subobj has only one block of subobjs, then move subobj's
         * subobjs to bpo's subobj list directly.  This reduces
         * recursion in bpobj_iterate due to nested subobjs.
         */
        subsubobjs = subbpo.bpo_phys->bpo_subobjs;
        if (subsubobjs != 0) {
                dmu_object_info_t doi;

                VERIFY3U(0, ==, dmu_object_info(bpo->bpo_os, subsubobjs, &doi));
                if (doi.doi_max_offset == doi.doi_data_block_size) {
                        dmu_buf_t *subdb;
                        uint64_t numsubsub = subbpo.bpo_phys->bpo_num_subobjs;

                        VERIFY3U(0, ==, dmu_buf_hold(bpo->bpo_os, subsubobjs,
                            0, FTAG, &subdb, 0));
                        /*
                         * Make sure that we are not asking dmu_write()
                         * to write more data than we have in our buffer.
                         */
                        VERIFY3U(subdb->db_size, >=,
                            numsubsub * sizeof (subobj));
                        dmu_write(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs,
                            bpo->bpo_phys->bpo_num_subobjs * sizeof (subobj),
                            numsubsub * sizeof (subobj), subdb->db_data, tx);
                        dmu_buf_rele(subdb, FTAG);
                        bpo->bpo_phys->bpo_num_subobjs += numsubsub;

                        dmu_buf_will_dirty(subbpo.bpo_dbuf, tx);
                        subbpo.bpo_phys->bpo_subobjs = 0;
                        VERIFY3U(0, ==, dmu_object_free(bpo->bpo_os,
                            subsubobjs, tx));
                }
        }
        bpo->bpo_phys->bpo_bytes += used;
        bpo->bpo_phys->bpo_comp += comp;
        bpo->bpo_phys->bpo_uncomp += uncomp;
        mutex_exit(&bpo->bpo_lock);

        bpobj_close(&subbpo);
}

void
bpobj_enqueue(bpobj_t *bpo, const blkptr_t *bp, dmu_tx_t *tx)
{
        blkptr_t stored_bp = *bp;
        uint64_t offset;
        int blkoff;
        blkptr_t *bparray;

        ASSERT(bpobj_is_open(bpo));
        ASSERT(!BP_IS_HOLE(bp));
        ASSERT(bpo->bpo_object != dmu_objset_pool(bpo->bpo_os)->dp_empty_bpobj);

        if (BP_IS_EMBEDDED(bp)) {
                /*
                 * The bpobj will compress better without the payload.
                 *
                 * Note that we store EMBEDDED bp's because they have an
                 * uncompressed size, which must be accounted for.  An
                 * alternative would be to add their size to bpo_uncomp
                 * without storing the bp, but that would create additional
                 * complications: bpo_uncomp would be inconsistent with the
                 * set of BP's stored, and bpobj_iterate() wouldn't visit
                 * all the space accounted for in the bpobj.
                 */
                bzero(&stored_bp, sizeof (stored_bp));
                stored_bp.blk_prop = bp->blk_prop;
                stored_bp.blk_birth = bp->blk_birth;
        } else if (!BP_GET_DEDUP(bp)) {
                /* The bpobj will compress better without the checksum */
                bzero(&stored_bp.blk_cksum, sizeof (stored_bp.blk_cksum));
        }

        /* We never need the fill count. */
        stored_bp.blk_fill = 0;

        mutex_enter(&bpo->bpo_lock);

        offset = bpo->bpo_phys->bpo_num_blkptrs * sizeof (stored_bp);
        blkoff = P2PHASE(bpo->bpo_phys->bpo_num_blkptrs, bpo->bpo_epb);

        if (bpo->bpo_cached_dbuf == NULL ||
            offset < bpo->bpo_cached_dbuf->db_offset ||
            offset >= bpo->bpo_cached_dbuf->db_offset +
            bpo->bpo_cached_dbuf->db_size) {
                if (bpo->bpo_cached_dbuf)
                        dmu_buf_rele(bpo->bpo_cached_dbuf, bpo);
                VERIFY3U(0, ==, dmu_buf_hold(bpo->bpo_os, bpo->bpo_object,
                    offset, bpo, &bpo->bpo_cached_dbuf, 0));
        }

        dmu_buf_will_dirty(bpo->bpo_cached_dbuf, tx);
        bparray = bpo->bpo_cached_dbuf->db_data;
        bparray[blkoff] = stored_bp;

        dmu_buf_will_dirty(bpo->bpo_dbuf, tx);
        bpo->bpo_phys->bpo_num_blkptrs++;
        bpo->bpo_phys->bpo_bytes +=
            bp_get_dsize_sync(dmu_objset_spa(bpo->bpo_os), bp);
        if (bpo->bpo_havecomp) {
                bpo->bpo_phys->bpo_comp += BP_GET_PSIZE(bp);
                bpo->bpo_phys->bpo_uncomp += BP_GET_UCSIZE(bp);
        }
        mutex_exit(&bpo->bpo_lock);
}

struct space_range_arg {
        spa_t *spa;
        uint64_t mintxg;
        uint64_t maxtxg;
        uint64_t used;
        uint64_t comp;
        uint64_t uncomp;
};

/* ARGSUSED */
static int
space_range_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
{
        struct space_range_arg *sra = arg;

        if (bp->blk_birth > sra->mintxg && bp->blk_birth <= sra->maxtxg) {
                if (dsl_pool_sync_context(spa_get_dsl(sra->spa)))
                        sra->used += bp_get_dsize_sync(sra->spa, bp);
                else
                        sra->used += bp_get_dsize(sra->spa, bp);
                sra->comp += BP_GET_PSIZE(bp);
                sra->uncomp += BP_GET_UCSIZE(bp);
        }
        return (0);
}

int
bpobj_space(bpobj_t *bpo, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
{
        ASSERT(bpobj_is_open(bpo));
        mutex_enter(&bpo->bpo_lock);

        *usedp = bpo->bpo_phys->bpo_bytes;
        if (bpo->bpo_havecomp) {
                *compp = bpo->bpo_phys->bpo_comp;
                *uncompp = bpo->bpo_phys->bpo_uncomp;
                mutex_exit(&bpo->bpo_lock);
                return (0);
        } else {
                mutex_exit(&bpo->bpo_lock);
                return (bpobj_space_range(bpo, 0, UINT64_MAX,
                    usedp, compp, uncompp));
        }
}

/*
 * Return the amount of space in the bpobj which is:
 * mintxg < blk_birth <= maxtxg
 */
int
bpobj_space_range(bpobj_t *bpo, uint64_t mintxg, uint64_t maxtxg,
    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
{
        struct space_range_arg sra = { 0 };
        int err;

        ASSERT(bpobj_is_open(bpo));

        /*
         * As an optimization, if they want the whole txg range, just
         * get bpo_bytes rather than iterating over the bps.
         */
        if (mintxg < TXG_INITIAL && maxtxg == UINT64_MAX && bpo->bpo_havecomp)
                return (bpobj_space(bpo, usedp, compp, uncompp));

        sra.spa = dmu_objset_spa(bpo->bpo_os);
        sra.mintxg = mintxg;
        sra.maxtxg = maxtxg;

        err = bpobj_iterate_nofree(bpo, space_range_cb, &sra, NULL);
        *usedp = sra.used;
        *compp = sra.comp;
        *uncompp = sra.uncomp;
        return (err);
}