/*
 * 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) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2018 by Delphix. All rights reserved.
 */

#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/zio.h>
#include <sys/ddt.h>
#include <sys/zap.h>
#include <sys/dmu_tx.h>
#include <util/sscanf.h>

int ddt_zap_leaf_blockshift = 12;
int ddt_zap_indirect_blockshift = 12;

static int
ddt_zap_create(objset_t *os, uint64_t *objectp, dmu_tx_t *tx, boolean_t prehash)
{
        zap_flags_t flags = ZAP_FLAG_HASH64 | ZAP_FLAG_UINT64_KEY;

        if (prehash)
                flags |= ZAP_FLAG_PRE_HASHED_KEY;

        *objectp = zap_create_flags(os, 0, flags, DMU_OT_DDT_ZAP,
            ddt_zap_leaf_blockshift, ddt_zap_indirect_blockshift,
            DMU_OT_NONE, 0, tx);

        return (*objectp == 0 ? ENOTSUP : 0);
}

static int
ddt_zap_destroy(objset_t *os, uint64_t object, dmu_tx_t *tx)
{
        return (zap_destroy(os, object, tx));
}

static int
ddt_zap_lookup(objset_t *os, uint64_t object, ddt_entry_t *dde)
{
        uchar_t cbuf[sizeof (dde->dde_phys) + 1];
        uint64_t one, csize;
        int error;

        error = zap_length_uint64(os, object, (uint64_t *)&dde->dde_key,
            DDT_KEY_WORDS, &one, &csize);
        if (error)
                return (error);

        ASSERT(one == 1);
        ASSERT(csize <= sizeof (cbuf));

        error = zap_lookup_uint64(os, object, (uint64_t *)&dde->dde_key,
            DDT_KEY_WORDS, 1, csize, cbuf);
        if (error)
                return (error);

        ddt_decompress(cbuf, dde->dde_phys, csize, sizeof (dde->dde_phys));

        return (0);
}

static void
ddt_zap_prefetch(objset_t *os, uint64_t object, ddt_entry_t *dde)
{
        (void) zap_prefetch_uint64(os, object, (uint64_t *)&dde->dde_key,
            DDT_KEY_WORDS);
}

static int
ddt_zap_update(objset_t *os, uint64_t object, ddt_entry_t *dde, dmu_tx_t *tx)
{
        uchar_t cbuf[sizeof (dde->dde_phys) + 1];
        uint64_t csize;

        csize = ddt_compress(dde->dde_phys, cbuf,
            sizeof (dde->dde_phys), sizeof (cbuf));

        return (zap_update_uint64(os, object, (uint64_t *)&dde->dde_key,
            DDT_KEY_WORDS, 1, csize, cbuf, tx));
}

static int
ddt_zap_remove(objset_t *os, uint64_t object, ddt_entry_t *dde, dmu_tx_t *tx)
{
        return (zap_remove_uint64(os, object, (uint64_t *)&dde->dde_key,
            DDT_KEY_WORDS, tx));
}

static int
ddt_zap_walk(objset_t *os, uint64_t object, ddt_entry_t *dde, uint64_t *walk)
{
        zap_cursor_t zc;
        zap_attribute_t za;
        int error;

        if (*walk == 0) {
                /*
                 * We don't want to prefetch the entire ZAP object, because
                 * it can be enormous.  Also the primary use of DDT iteration
                 * is for scrubbing, in which case we will be issuing many
                 * scrub i/os for each ZAP block that we read in, so
                 * reading the ZAP is unlikely to be the bottleneck.
                 */
                zap_cursor_init_noprefetch(&zc, os, object);
        } else {
                zap_cursor_init_serialized(&zc, os, object, *walk);
        }
        if ((error = zap_cursor_retrieve(&zc, &za)) == 0) {
                uchar_t cbuf[sizeof (dde->dde_phys) + 1];
                uint64_t csize = za.za_num_integers;
                ASSERT(za.za_integer_length == 1);
                error = zap_lookup_uint64(os, object, (uint64_t *)za.za_name,
                    DDT_KEY_WORDS, 1, csize, cbuf);
                ASSERT(error == 0);
                if (error == 0) {
                        ddt_decompress(cbuf, dde->dde_phys, csize,
                            sizeof (dde->dde_phys));
                        dde->dde_key = *(ddt_key_t *)za.za_name;
                }
                zap_cursor_advance(&zc);
                *walk = zap_cursor_serialize(&zc);
        }
        zap_cursor_fini(&zc);
        return (error);
}

static uint64_t
ddt_zap_count(objset_t *os, uint64_t object)
{
        uint64_t count = 0;

        VERIFY(zap_count(os, object, &count) == 0);

        return (count);
}

const ddt_ops_t ddt_zap_ops = {
        "zap",
        ddt_zap_create,
        ddt_zap_destroy,
        ddt_zap_lookup,
        ddt_zap_prefetch,
        ddt_zap_update,
        ddt_zap_remove,
        ddt_zap_walk,
        ddt_zap_count,
};