Features/QED

Specification

The file format looks like this:

+--------+--------------+---------+---------+-----+
| header | extent table | extent0 | extent1 | ... |
+--------+--------------+---------+---------+-----+

Header

Header {
    uint32_t magic;               /* COW2 */
    uint32_t features;            /* format feature bits */

    uint32_t cluster_size;        /* in bytes */
    uint32_t table_size;          /* table chunk size, in clusters */
    uint64_t l1_table_offset;     /* L1 table offset, in cluster */
    uint64_t image_size;          /* total image size, in clusters */

    uint32_t backing_file_offset; /* in bytes from start of header */
    uint32_t backing_file_size;   /* in bytes */
}