disk Structures

A disk structure is the kernel’s representation of an individual disk-like storage device. It is defined in the <geom/geom_disk.h> header as follows:

struct disk {
        /* GEOM Private Data */
        struct g_geom          *d_geom;
        struct devstat         *d_devstat;
        int                     d_destroyed;

        /* Shared Objects */
        struct bio_queue_head  *d_queue;
        struct mtx             *d_lock;

        /* Descriptive Fields */
        const char             *d_name;
        u_int                   d_unit;
        u_int                   d_flags;

        /* Storage Device Methods */
        disk_open_t            *d_open;
        disk_close_t           *d_close;
        disk_strategy_t        *d_strategy;
        disk_ioctl_t           *d_ioctl;
        dumper_t               *d_dump;

        /* Mandatory Media Properties */
        u_int          ....