linux/block/partitions/sgi.c
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   1/*
   2 *  fs/partitions/sgi.c
   3 *
   4 *  Code extracted from drivers/block/genhd.c
   5 */
   6
   7#include "check.h"
   8#include "sgi.h"
   9
  10struct sgi_disklabel {
  11        __be32 magic_mushroom;          /* Big fat spliff... */
  12        __be16 root_part_num;           /* Root partition number */
  13        __be16 swap_part_num;           /* Swap partition number */
  14        s8 boot_file[16];               /* Name of boot file for ARCS */
  15        u8 _unused0[48];                /* Device parameter useless crapola.. */
  16        struct sgi_volume {
  17                s8 name[8];             /* Name of volume */
  18                __be32 block_num;               /* Logical block number */
  19                __be32 num_bytes;               /* How big, in bytes */
  20        } volume[15];
  21        struct sgi_partition {
  22                __be32 num_blocks;              /* Size in logical blocks */
  23                __be32 first_block;     /* First logical block */
  24                __be32 type;            /* Type of this partition */
  25        } partitions[16];
  26        __be32 csum;                    /* Disk label checksum */
  27        __be32 _unused1;                        /* Padding */
  28};
  29
  30int sgi_partition(struct parsed_partitions *state)
  31{
  32        int i, csum;
  33        __be32 magic;
  34        int slot = 1;
  35        unsigned int start, blocks;
  36        __be32 *ui, cs;
  37        Sector sect;
  38        struct sgi_disklabel *label;
  39        struct sgi_partition *p;
  40        char b[BDEVNAME_SIZE];
  41
  42        label = read_part_sector(state, 0, &sect);
  43        if (!label)
  44                return -1;
  45        p = &label->partitions[0];
  46        magic = label->magic_mushroom;
  47        if(be32_to_cpu(magic) != SGI_LABEL_MAGIC) {
  48                /*printk("Dev %s SGI disklabel: bad magic %08x\n",
  49                       bdevname(bdev, b), be32_to_cpu(magic));*/
  50                put_dev_sector(sect);
  51                return 0;
  52        }
  53        ui = ((__be32 *) (label + 1)) - 1;
  54        for(csum = 0; ui >= ((__be32 *) label);) {
  55                cs = *ui--;
  56                csum += be32_to_cpu(cs);
  57        }
  58        if(csum) {
  59                printk(KERN_WARNING "Dev %s SGI disklabel: csum bad, label corrupted\n",
  60                       bdevname(state->bdev, b));
  61                put_dev_sector(sect);
  62                return 0;
  63        }
  64        /* All SGI disk labels have 16 partitions, disks under Linux only
  65         * have 15 minor's.  Luckily there are always a few zero length
  66         * partitions which we don't care about so we never overflow the
  67         * current_minor.
  68         */
  69        for(i = 0; i < 16; i++, p++) {
  70                blocks = be32_to_cpu(p->num_blocks);
  71                start  = be32_to_cpu(p->first_block);
  72                if (blocks) {
  73                        put_partition(state, slot, start, blocks);
  74                        if (be32_to_cpu(p->type) == LINUX_RAID_PARTITION)
  75                                state->parts[slot].flags = ADDPART_FLAG_RAID;
  76                }
  77                slot++;
  78        }
  79        strlcat(state->pp_buf, "\n", PAGE_SIZE);
  80        put_dev_sector(sect);
  81        return 1;
  82}
  83
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