root/fs/partitions/sgi.c

DEFINITIONS

1. sgi_partition

/*
 *  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, struct block_device *bdev)
{
        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 = (struct sgi_disklabel *) read_dev_sector(bdev, 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(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++;
        }
        printk("\n");
        put_dev_sector(sect);
        return 1;
}