int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) { BDRVQcowState *s = bs->opaque; QCowSnapshot *sn; int i, snapshot_index, l1_size2; snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id); if (snapshot_index < 0) return -ENOENT; sn = &s->snapshots[snapshot_index]; if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0) goto fail; if (qcow2_grow_l1_table(bs, sn->l1_size) < 0) goto fail; s->l1_size = sn->l1_size; l1_size2 = s->l1_size * sizeof(uint64_t); /* copy the snapshot l1 table to the current l1 table */ if (bdrv_pread(bs->file, sn->l1_table_offset, s->l1_table, l1_size2) != l1_size2) goto fail; if (bdrv_pwrite(bs->file, s->l1_table_offset, s->l1_table, l1_size2) != l1_size2) goto fail; for(i = 0;i < s->l1_size; i++) { be64_to_cpus(&s->l1_table[i]); } if (qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0) goto fail; #ifdef DEBUG_ALLOC qcow2_check_refcounts(bs); #endif return 0; fail: return -EIO; }