sgi.c

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/*
 *  fs/partitions/sgi.c
 *
 *  Code extracted from drivers/block/genhd.c
 */

#include "check.h"
#include "sgi.h"

struct sgi_disklabel {
    __be32 magic_mushroom;      /* Big fat spliff... */
    __be16 root_part_num;       /* Root partition number */
    __be16 swap_part_num;       /* Swap partition number */
    s8 boot_file[16];       /* Name of boot file for ARCS */
    u8 _unused0[48];        /* Device parameter useless crapola.. */
    struct sgi_volume {
        s8 name[8];     /* Name of volume */
        __be32 block_num;       /* Logical block number */
        __be32 num_bytes;       /* How big, in bytes */
    } volume[15];
    struct sgi_partition {
        __be32 num_blocks;      /* Size in logical blocks */
        __be32 first_block; /* First logical block */
        __be32 type;        /* Type of this partition */
    } partitions[16];
    __be32 csum;            /* Disk label checksum */
    __be32 _unused1;            /* Padding */
};

int sgi_partition(struct parsed_partitions *state)
{
    int i, csum;
    __be32 magic;
    int slot = 1;
    unsigned int start, blocks;
    __be32 *ui, cs;
    Sector sect;
    struct sgi_disklabel *label;
    struct sgi_partition *p;
    char b[BDEVNAME_SIZE];

    label = read_part_sector(state, 0, &sect);
    if (!label)
        return -1;
    p = &label->partitions[0];
    magic = label->magic_mushroom;
    if(be32_to_cpu(magic) != SGI_LABEL_MAGIC) {
        /*printk("Dev %s SGI disklabel: bad magic %08x\n",
               bdevname(bdev, b), be32_to_cpu(magic));*/
        put_dev_sector(sect);
        return 0;
    }
    ui = ((__be32 *) (label + 1)) - 1;
    for(csum = 0; ui >= ((__be32 *) label);) {
        cs = *ui--;
        csum += be32_to_cpu(cs);
    }
    if(csum) {
        printk(KERN_WARNING "Dev %s SGI disklabel: csum bad, label corrupted\n",
               bdevname(state->bdev, b));
        put_dev_sector(sect);
        return 0;
    }
    /* All SGI disk labels have 16 partitions, disks under Linux only
     * have 15 minor's.  Luckily there are always a few zero length
     * partitions which we don't care about so we never overflow the
     * current_minor.
     */
    for(i = 0; i < 16; i++, p++) {
        blocks = be32_to_cpu(p->num_blocks);
        start  = be32_to_cpu(p->first_block);
        if (blocks) {
            put_partition(state, slot, start, blocks);
            if (be32_to_cpu(p->type) == LINUX_RAID_PARTITION)
                state->parts[slot].flags = ADDPART_FLAG_RAID;
        }
        slot++;
    }
    strlcat(state->pp_buf, "\n", PAGE_SIZE);
    put_dev_sector(sect);
    return 1;
}