static int enable_write_target(BDRVVVFATState *s, Error **errp) { BlockDriver *bdrv_qcow; QEMUOptionParameter *options; int ret; int size = sector2cluster(s, s->sector_count); s->used_clusters = calloc(size, 1); array_init(&(s->commits), sizeof(commit_t)); s->qcow_filename = g_malloc(1024); ret = get_tmp_filename(s->qcow_filename, 1024); if (ret < 0) { error_setg_errno(errp, -ret, "can't create temporary file"); goto err; } bdrv_qcow = bdrv_find_format("qcow"); options = parse_option_parameters("", bdrv_qcow->create_options, NULL); set_option_parameter_int(options, BLOCK_OPT_SIZE, s->sector_count * 512); set_option_parameter(options, BLOCK_OPT_BACKING_FILE, "fat:"); ret = bdrv_create(bdrv_qcow, s->qcow_filename, options, errp); if (ret < 0) { goto err; } s->qcow = NULL; ret = bdrv_open(&s->qcow, s->qcow_filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, bdrv_qcow, errp); if (ret < 0) { goto err; } #ifndef _WIN32 unlink(s->qcow_filename); #endif bdrv_set_backing_hd(s->bs, bdrv_new("", &error_abort)); s->bs->backing_hd->drv = &vvfat_write_target; s->bs->backing_hd->opaque = g_malloc(sizeof(void*)); *(void**)s->bs->backing_hd->opaque = s; return 0; err: g_free(s->qcow_filename); s->qcow_filename = NULL; return ret; }