/*
 * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $DragonFly: src/sbin/hammer/blockmap.c,v 1.2 2008/06/17 04:03:38 dillon Exp $
 */

#include "hammer_util.h"

/*
 * Allocate big-blocks using our poor-man's volume->vol_free_off.
 * We are bootstrapping the freemap itself and cannot update it yet.
 */
hammer_off_t
bootstrap_bigblock(volume_info_t volume)
{
        hammer_off_t result_offset;

        assert_volume_offset(volume);
        result_offset = volume->vol_free_off;

        volume->vol_free_off += HAMMER_BIGBLOCK_SIZE;

        return(result_offset);
}

/*
 * Allocate a big-block for zone-3 for UNDO/REDO FIFO.
 */
hammer_off_t
alloc_undo_bigblock(volume_info_t volume)
{
        hammer_blockmap_t freemap;
        buffer_info_t buffer1 = NULL;
        buffer_info_t buffer2 = NULL;
        hammer_blockmap_layer1_t layer1;
        hammer_blockmap_layer2_t layer2;
        hammer_off_t layer1_offset;
        hammer_off_t layer2_offset;
        hammer_off_t result_offset;

        /* Only root volume needs formatting */
        assert(volume->vol_no == HAMMER_ROOT_VOLNO);

        result_offset = bootstrap_bigblock(volume);
        freemap = &volume->ondisk->vol0_blockmap[HAMMER_ZONE_FREEMAP_INDEX];

        /*
         * Dive layer 1.
         */
        layer1_offset = freemap->phys_offset +
                        HAMMER_BLOCKMAP_LAYER1_OFFSET(result_offset);
        layer1 = get_buffer_data(layer1_offset, &buffer1, 0);
        assert(layer1->phys_offset != HAMMER_BLOCKMAP_UNAVAIL);
        --layer1->blocks_free;
        hammer_crc_set_layer1(HammerVersion, layer1);
        buffer1->cache.modified = 1;

        /*
         * Dive layer 2, each entry represents a big-block.
         */
        layer2_offset = layer1->phys_offset +
                        HAMMER_BLOCKMAP_LAYER2_OFFSET(result_offset);
        layer2 = get_buffer_data(layer2_offset, &buffer2, 0);
        assert(layer2->zone == 0);
        layer2->zone = HAMMER_ZONE_UNDO_INDEX;
        layer2->append_off = HAMMER_BIGBLOCK_SIZE;
        layer2->bytes_free = 0;
        hammer_crc_set_layer2(HammerVersion, layer2);
        buffer2->cache.modified = 1;

        --volume->ondisk->vol0_stat_freebigblocks;

        rel_buffer(buffer1);
        rel_buffer(buffer2);

        return(result_offset);
}

/*
 * Allocate a chunk of data out of a blockmap.  This is a simplified
 * version which uses next_offset as a simple allocation iterator.
 */
void *
alloc_blockmap(int zone, int bytes, hammer_off_t *result_offp,
               buffer_info_t *bufferp)
{
        volume_info_t volume;
        hammer_blockmap_t blockmap;
        hammer_blockmap_t freemap;
        buffer_info_t buffer1 = NULL;
        buffer_info_t buffer2 = NULL;
        hammer_blockmap_layer1_t layer1;
        hammer_blockmap_layer2_t layer2;
        hammer_off_t tmp_offset;
        hammer_off_t layer1_offset;
        hammer_off_t layer2_offset;
        void *ptr;

        volume = get_root_volume();

        blockmap = &volume->ondisk->vol0_blockmap[zone];
        freemap = &volume->ondisk->vol0_blockmap[HAMMER_ZONE_FREEMAP_INDEX];
        assert(HAMMER_ZONE_DECODE(blockmap->next_offset) == zone);

        /*
         * Alignment and buffer-boundary issues.  If the allocation would
         * cross a buffer boundary we have to skip to the next buffer.
         */
        bytes = HAMMER_DATA_DOALIGN(bytes);
        assert(bytes > 0 && bytes <= HAMMER_BUFSIZE);  /* not HAMMER_XBUFSIZE */
        assert(hammer_is_index_record(zone));

again:
        assert(blockmap->next_offset != HAMMER_ZONE_ENCODE(zone + 1, 0));

        tmp_offset = blockmap->next_offset + bytes - 1;
        if ((blockmap->next_offset ^ tmp_offset) & ~HAMMER_BUFMASK64)
                blockmap->next_offset = tmp_offset & ~HAMMER_BUFMASK64;

        /*
         * Dive layer 1.
         */
        layer1_offset = freemap->phys_offset +
                        HAMMER_BLOCKMAP_LAYER1_OFFSET(blockmap->next_offset);
        layer1 = get_buffer_data(layer1_offset, &buffer1, 0);
        assert(layer1->phys_offset != HAMMER_BLOCKMAP_UNAVAIL);
        assert(!((blockmap->next_offset & HAMMER_BIGBLOCK_MASK) == 0 &&
                layer1->blocks_free == 0));

        /*
         * Dive layer 2, each entry represents a big-block.
         */
        layer2_offset = layer1->phys_offset +
                        HAMMER_BLOCKMAP_LAYER2_OFFSET(blockmap->next_offset);
        layer2 = get_buffer_data(layer2_offset, &buffer2, 0);

        if (layer2->zone == HAMMER_ZONE_UNAVAIL_INDEX) {
                errx(1, "alloc_blockmap: layer2 ran out of space!");
                /* not reached */
        }

        /*
         * If we are entering a new big-block assign ownership to our
         * zone.  If the big-block is owned by another zone skip it.
         */
        if (layer2->zone == 0) {
                --layer1->blocks_free;
                hammer_crc_set_layer1(HammerVersion, layer1);
                layer2->zone = zone;
                --volume->ondisk->vol0_stat_freebigblocks;
                assert(layer2->bytes_free == HAMMER_BIGBLOCK_SIZE);
                assert(layer2->append_off == 0);
        }
        if (layer2->zone != zone) {
                blockmap->next_offset =
                        HAMMER_ZONE_LAYER2_NEXT_OFFSET(blockmap->next_offset);
                goto again;
        }

        assert(layer2->append_off ==
                (blockmap->next_offset & HAMMER_BIGBLOCK_MASK));
        layer2->bytes_free -= bytes;
        *result_offp = blockmap->next_offset;
        blockmap->next_offset += bytes;
        layer2->append_off = (int)blockmap->next_offset & HAMMER_BIGBLOCK_MASK;
        hammer_crc_set_layer2(HammerVersion, layer2);

        ptr = get_buffer_data(*result_offp, bufferp, 0);
        (*bufferp)->cache.modified = 1;

        buffer1->cache.modified = 1;
        buffer2->cache.modified = 1;

        rel_buffer(buffer1);
        rel_buffer(buffer2);
        return(ptr);
}

hammer_off_t
blockmap_lookup(hammer_off_t zone_offset, int *errorp)
{
        return(blockmap_lookup_save(zone_offset, NULL, NULL, errorp));
}

hammer_off_t
blockmap_lookup_save(hammer_off_t zone_offset,
                hammer_blockmap_layer1_t save_layer1,
                hammer_blockmap_layer2_t save_layer2,
                int *errorp)
{
        volume_info_t root_volume = NULL;
        hammer_volume_ondisk_t ondisk;
        hammer_blockmap_t blockmap;
        hammer_blockmap_t freemap;
        hammer_blockmap_layer1_t layer1;
        hammer_blockmap_layer2_t layer2;
        buffer_info_t buffer1 = NULL;
        buffer_info_t buffer2 = NULL;
        hammer_off_t layer1_offset;
        hammer_off_t layer2_offset;
        hammer_off_t result_offset = HAMMER_OFF_BAD;;
        int zone;
        int error = 0;

        if (save_layer1)
                bzero(save_layer1, sizeof(*save_layer1));
        if (save_layer2)
                bzero(save_layer2, sizeof(*save_layer2));

        zone = HAMMER_ZONE_DECODE(zone_offset);

        if (zone <= HAMMER_ZONE_RAW_VOLUME_INDEX) {
                error = -1;
                goto done;
        }
        if (zone >= HAMMER_MAX_ZONES) {
                error = -2;
                goto done;
        }

        root_volume = get_root_volume();
        ondisk = root_volume->ondisk;
        blockmap = &ondisk->vol0_blockmap[zone];

        /*
         * Handle blockmap offset translations.
         */
        if (hammer_is_index_record(zone)) {
                result_offset = hammer_xlate_to_zone2(zone_offset);
        } else if (zone == HAMMER_ZONE_UNDO_INDEX) {
                if (zone_offset >= blockmap->alloc_offset) {
                        error = -3;
                        goto done;
                }
                result_offset = hammer_xlate_to_undo(ondisk, zone_offset);
        } else {
                /* assert(zone == HAMMER_ZONE_RAW_BUFFER_INDEX); */
                result_offset = zone_offset;
        }

        /*
         * The blockmap should match the requested zone (else the volume
         * header is mashed).
         */
        if (hammer_is_index_record(zone) &&
            HAMMER_ZONE_DECODE(blockmap->alloc_offset) != zone) {
                error = -4;
                goto done;
        }

        /*
         * Validate that the big-block is assigned to the zone.  Also
         * assign save_layer{1,2} if not NULL.
         */
        freemap = &ondisk->vol0_blockmap[HAMMER_ZONE_FREEMAP_INDEX];

        /*
         * Dive layer 1.
         */
        layer1_offset = freemap->phys_offset +
                        HAMMER_BLOCKMAP_LAYER1_OFFSET(result_offset);
        layer1 = get_buffer_data(layer1_offset, &buffer1, 0);

        if (layer1 == NULL) {
                error = -5;
                goto done;
        }
        if (layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL) {
                error = -6;
                goto done;
        }
        if (save_layer1)
                *save_layer1 = *layer1;

        /*
         * Dive layer 2, each entry represents a big-block.
         */
        layer2_offset = layer1->phys_offset +
                        HAMMER_BLOCKMAP_LAYER2_OFFSET(result_offset);
        layer2 = get_buffer_data(layer2_offset, &buffer2, 0);

        if (layer2 == NULL) {
                error = -7;
                goto done;
        }
        if (layer2->zone != zone) {
                error = -8;
                goto done;
        }
        if (save_layer2)
                *save_layer2 = *layer2;

done:
        rel_buffer(buffer1);
        rel_buffer(buffer2);

        if (errorp)
                *errorp = error;

        return(result_offset);
}