int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

                          BdrvCheckMode fix)

{

    BDRVQcowState *s = bs->opaque;

    int64_t size, i, highest_cluster, nb_clusters;

    int refcount1, refcount2;

    QCowSnapshot *sn;

    uint16_t *refcount_table;

    int ret;



    size = bdrv_getlength(bs->file);

    if (size < 0) {

        res->check_errors++;

        return size;

    }



    nb_clusters = size_to_clusters(s, size);

    if (nb_clusters > INT_MAX) {

        res->check_errors++;

        return -EFBIG;

    }



    refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t));



    res->bfi.total_clusters =

        size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE);



    

    inc_refcounts(bs, res, refcount_table, nb_clusters,

        0, s->cluster_size);



    

    ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,

                             s->l1_table_offset, s->l1_size, CHECK_FRAG_INFO);

    if (ret < 0) {

        goto fail;

    }



    

    for(i = 0; i < s->nb_snapshots; i++) {

        sn = s->snapshots + i;

        ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,

            sn->l1_table_offset, sn->l1_size, 0);

        if (ret < 0) {

            goto fail;

        }

    }

    inc_refcounts(bs, res, refcount_table, nb_clusters,

        s->snapshots_offset, s->snapshots_size);



    

    inc_refcounts(bs, res, refcount_table, nb_clusters,

        s->refcount_table_offset,

        s->refcount_table_size * sizeof(uint64_t));



    for(i = 0; i < s->refcount_table_size; i++) {

        uint64_t offset, cluster;

        offset = s->refcount_table[i];

        cluster = offset >> s->cluster_bits;



        

        if (offset_into_cluster(s, offset)) {

            fprintf(stderr, "ERROR refcount block %" PRId64 " is not "

                "cluster aligned; refcount table entry corrupted\n", i);

            res->corruptions++;

            continue;

        }



        if (cluster >= nb_clusters) {

            fprintf(stderr, "ERROR refcount block %" PRId64

                    " is outside image\n", i);

            res->corruptions++;

            continue;

        }



        if (offset != 0) {

            inc_refcounts(bs, res, refcount_table, nb_clusters,

                offset, s->cluster_size);

            if (refcount_table[cluster] != 1) {

                fprintf(stderr, "%s refcount block %" PRId64

                    " refcount=%d\n",

                    fix & BDRV_FIX_ERRORS ? "Repairing" :

                                            "ERROR",

                    i, refcount_table[cluster]);



                if (fix & BDRV_FIX_ERRORS) {

                    int64_t new_offset;



                    new_offset = realloc_refcount_block(bs, i, offset);

                    if (new_offset < 0) {

                        res->corruptions++;

                        continue;

                    }



                    

                    if ((new_offset >> s->cluster_bits) >= nb_clusters) {

                        

                        int old_nb_clusters = nb_clusters;

                        nb_clusters = (new_offset >> s->cluster_bits) + 1;

                        refcount_table = g_realloc(refcount_table,

                                nb_clusters * sizeof(uint16_t));

                        memset(&refcount_table[old_nb_clusters], 0, (nb_clusters

                                - old_nb_clusters) * sizeof(uint16_t));

                    }

                    refcount_table[cluster]--;

                    inc_refcounts(bs, res, refcount_table, nb_clusters,

                            new_offset, s->cluster_size);



                    res->corruptions_fixed++;

                } else {

                    res->corruptions++;

                }

            }

        }

    }



    

    for (i = 0, highest_cluster = 0; i < nb_clusters; i++) {

        refcount1 = get_refcount(bs, i);

        if (refcount1 < 0) {

            fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n",

                i, strerror(-refcount1));

            res->check_errors++;

            continue;

        }



        refcount2 = refcount_table[i];



        if (refcount1 > 0 || refcount2 > 0) {

            highest_cluster = i;

        }



        if (refcount1 != refcount2) {



            

            int *num_fixed = NULL;

            if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) {

                num_fixed = &res->leaks_fixed;

            } else if (refcount1 < refcount2 && (fix & BDRV_FIX_ERRORS)) {

                num_fixed = &res->corruptions_fixed;

            }



            fprintf(stderr, "%s cluster %" PRId64 " refcount=%d reference=%d\n",

                   num_fixed != NULL     ? "Repairing" :

                   refcount1 < refcount2 ? "ERROR" :

                                           "Leaked",

                   i, refcount1, refcount2);



            if (num_fixed) {

                ret = update_refcount(bs, i << s->cluster_bits, 1,

                                      refcount2 - refcount1,

                                      QCOW2_DISCARD_ALWAYS);

                if (ret >= 0) {

                    (*num_fixed)++;

                    continue;

                }

            }



            

            if (refcount1 < refcount2) {

                res->corruptions++;

            } else {

                res->leaks++;

            }

        }

    }



    

    ret = check_oflag_copied(bs, res, fix);

    if (ret < 0) {

        goto fail;

    }



    res->image_end_offset = (highest_cluster + 1) * s->cluster_size;

    ret = 0;



fail:

    g_free(refcount_table);



    return ret;

}
