// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#include "dm-space-map-common.h"
#include "dm-space-map-disk.h"
#include "dm-space-map.h"
#include "dm-transaction-manager.h"

#include <linux/list.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "space map disk"

/*----------------------------------------------------------------*/

/*
 * Space map interface.
 */
struct sm_disk {
        struct dm_space_map sm;

        struct ll_disk ll;
        struct ll_disk old_ll;

        dm_block_t begin;
        dm_block_t nr_allocated_this_transaction;
};

static void sm_disk_destroy(struct dm_space_map *sm)
{
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        kfree(smd);
}

static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
{
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        return sm_ll_extend(&smd->ll, extra_blocks);
}

static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
{
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        *count = smd->old_ll.nr_blocks;

        return 0;
}

static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
{
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;

        return 0;
}

static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
                             uint32_t *result)
{
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        return sm_ll_lookup(&smd->ll, b, result);
}

static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
                                          int *result)
{
        int r;
        uint32_t count;

        r = sm_disk_get_count(sm, b, &count);
        if (r)
                return r;

        *result = count > 1;

        return 0;
}

static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
                             uint32_t count)
{
        int r;
        int32_t nr_allocations;
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        r = sm_ll_insert(&smd->ll, b, count, &nr_allocations);
        if (!r)
                smd->nr_allocated_this_transaction += nr_allocations;

        return r;
}

static int sm_disk_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
{
        int r;
        int32_t nr_allocations;
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        r = sm_ll_inc(&smd->ll, b, e, &nr_allocations);
        if (!r)
                smd->nr_allocated_this_transaction += nr_allocations;

        return r;
}

static int sm_disk_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
{
        int r;
        int32_t nr_allocations;
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        r = sm_ll_dec(&smd->ll, b, e, &nr_allocations);
        if (!r)
                smd->nr_allocated_this_transaction += nr_allocations;

        return r;
}

static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
{
        int r;
        int32_t nr_allocations;
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        /*
         * Any block we allocate has to be free in both the old and current ll.
         */
        r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b);
        if (r == -ENOSPC)
                /*
                 * There's no free block between smd->begin and the end of the metadata device.
                 * We search before smd->begin in case something has been freed.
                 */
                r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, 0, smd->begin, b);

        if (r)
                return r;

        smd->begin = *b + 1;
        r = sm_ll_inc(&smd->ll, *b, *b + 1, &nr_allocations);
        if (!r)
                smd->nr_allocated_this_transaction += nr_allocations;

        return r;
}

static int sm_disk_commit(struct dm_space_map *sm)
{
        int r;
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

        r = sm_ll_commit(&smd->ll);
        if (r)
                return r;

        memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
        smd->nr_allocated_this_transaction = 0;

        return 0;
}

static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
{
        *result = sizeof(struct disk_sm_root);

        return 0;
}

static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
{
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
        struct disk_sm_root root_le;

        root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
        root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
        root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
        root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);

        if (max < sizeof(root_le))
                return -ENOSPC;

        memcpy(where_le, &root_le, sizeof(root_le));

        return 0;
}

/*----------------------------------------------------------------*/

static struct dm_space_map ops = {
        .destroy = sm_disk_destroy,
        .extend = sm_disk_extend,
        .get_nr_blocks = sm_disk_get_nr_blocks,
        .get_nr_free = sm_disk_get_nr_free,
        .get_count = sm_disk_get_count,
        .count_is_more_than_one = sm_disk_count_is_more_than_one,
        .set_count = sm_disk_set_count,
        .inc_blocks = sm_disk_inc_blocks,
        .dec_blocks = sm_disk_dec_blocks,
        .new_block = sm_disk_new_block,
        .commit = sm_disk_commit,
        .root_size = sm_disk_root_size,
        .copy_root = sm_disk_copy_root,
        .register_threshold_callback = NULL
};

struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
                                       dm_block_t nr_blocks)
{
        int r;
        struct sm_disk *smd;

        smd = kmalloc_obj(*smd);
        if (!smd)
                return ERR_PTR(-ENOMEM);

        smd->begin = 0;
        smd->nr_allocated_this_transaction = 0;
        memcpy(&smd->sm, &ops, sizeof(smd->sm));

        r = sm_ll_new_disk(&smd->ll, tm);
        if (r)
                goto bad;

        r = sm_ll_extend(&smd->ll, nr_blocks);
        if (r)
                goto bad;

        r = sm_disk_commit(&smd->sm);
        if (r)
                goto bad;

        return &smd->sm;

bad:
        kfree(smd);
        return ERR_PTR(r);
}
EXPORT_SYMBOL_GPL(dm_sm_disk_create);

struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
                                     void *root_le, size_t len)
{
        int r;
        struct sm_disk *smd;

        smd = kmalloc_obj(*smd);
        if (!smd)
                return ERR_PTR(-ENOMEM);

        smd->begin = 0;
        smd->nr_allocated_this_transaction = 0;
        memcpy(&smd->sm, &ops, sizeof(smd->sm));

        r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
        if (r)
                goto bad;

        r = sm_disk_commit(&smd->sm);
        if (r)
                goto bad;

        return &smd->sm;

bad:
        kfree(smd);
        return ERR_PTR(r);
}
EXPORT_SYMBOL_GPL(dm_sm_disk_open);

/*----------------------------------------------------------------*/