super-mbr.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2010 Neil Brown <neilb@suse.de>
   5  *
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2 of the License, or
  10  *    (at your option) any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *    Author: Neil Brown
  22  *    Email: <neil@brown.name>
  23  *
  24  */
  25
  26 /*
  27  * 'mbr' is a pseudo metadata type for devices which have a
  28  * partition table in the Master Boot Record (mbr) also known
  29  * as a dos partition table.
  30  *
  31  * Obviously arrays cannot be created or assembled for this type.
  32  * It is used to allow a new bare device to have an partition table
  33  * added so the member partitions can then be included in other
  34  * arrays as relevant.
  35  *
  36  * The meaning operations are:
  37  * examine_super, but not brief_examine_super or export_examine
  38  * load_super
  39  * store_super
  40  */
  41
  42 #include "mdadm.h"
  43 #include "part.h"
  44
  45 static void free_mbr(struct supertype *st)
  46 {
  47         free(st->sb);
  48         st->sb = NULL;
  49 }
  50
  51 #ifndef MDASSEMBLE
  52
  53 static void examine_mbr(struct supertype *st, char *homehost)
  54 {
  55         struct MBR *sb = st->sb;
  56         int i;
  57
  58         printf("   MBR Magic : %04x\n", sb->magic);
  59         for (i = 0; i < MBR_PARTITIONS; i++)
  60                 if (sb->parts[i].blocks_num)
  61                         printf("Partition[%d] : %12lu sectors at %12lu (type %02x)\n",
  62                                i,
  63                                (unsigned long)__le32_to_cpu(sb->parts[i].blocks_num),
  64                                (unsigned long)__le32_to_cpu(sb->parts[i].first_sect_lba),
  65                                sb->parts[i].part_type);
  66
  67 }
  68
  69 #endif /*MDASSEMBLE */
  70
  71 static int load_super_mbr(struct supertype *st, int fd, char *devname)
  72 {
  73         /* try to read an mbr
  74          * Return
  75          *  0 on success
  76          *  1 cannot get record
  77          *  2 record is meaningless
  78          */
  79         struct MBR *super;
  80
  81         free_mbr(st);
  82
  83         if (posix_memalign((void**)&super, 512, 512) != 0) {
  84                 pr_err("%s could not allocate superblock\n",
  85                         __func__);
  86                 return 1;
  87         }
  88
  89         lseek(fd, 0, 0);
  90         if (read(fd, super, sizeof(*super)) != sizeof(*super)) {
  91                 if (devname)
  92                         pr_err("Cannot read partition table on %s\n",
  93                                 devname);
  94                 free(super);
  95                 return 1;
  96         }
  97
  98         if (super->magic != MBR_SIGNATURE_MAGIC) {
  99                 if (devname)
 100                         pr_err("No partition table found on %s\n",
 101                                 devname);
 102                 free(super);
 103                 return 1;
 104         }
 105
 106         st->sb = super;
 107
 108         if (st->ss == NULL) {
 109                 st->ss = &mbr;
 110                 st->minor_version = 0;
 111                 st->max_devs = 1;
 112                 st->info = NULL;
 113         }
 114         return 0;
 115 }
 116
 117 static int store_mbr(struct supertype *st, int fd)
 118 {
 119         struct MBR *old, *super;
 120
 121         if (posix_memalign((void**)&old, 512, 512) != 0) {
 122                 pr_err("%s could not allocate superblock\n",
 123                         __func__);
 124                 return 1;
 125         }
 126
 127         lseek(fd, 0, 0);
 128         if (read(fd, old, sizeof(*old)) != sizeof(*old)) {
 129                 free(old);
 130                 return 1;
 131         }
 132
 133         super = st->sb;
 134         memcpy(super->pad, old->pad, sizeof(super->pad));
 135         free(old);
 136         lseek(fd, 0, 0);
 137         if (write(fd, super, sizeof(*super)) != sizeof(*super))
 138                 return 4;
 139         fsync(fd);
 140         ioctl(fd, BLKRRPART, 0);
 141         return 0;
 142 }
 143
 144 static void getinfo_mbr(struct supertype *st, struct mdinfo *info, char *map)
 145 {
 146         struct MBR *sb = st->sb;
 147         int i;
 148
 149         memset(&info->array, 0, sizeof(info->array));
 150         memset(&info->disk, 0, sizeof(info->disk));
 151         strcpy(info->text_version, "mbr");
 152         strcpy(info->name, "mbr");
 153         info->component_size = 0;
 154
 155         for (i = 0; i < MBR_PARTITIONS ; i++)
 156                 if (sb->parts[i].blocks_num) {
 157                         unsigned long last =
 158                                 (unsigned long)__le32_to_cpu(sb->parts[i].blocks_num)
 159                                 + (unsigned long)__le32_to_cpu(sb->parts[i].first_sect_lba);
 160                         if (last > info->component_size)
 161                                 info->component_size = last;
 162                 }
 163
 164 }
 165
 166 static struct supertype *match_metadata_desc(char *arg)
 167 {
 168         struct supertype *st;
 169
 170         if (strcmp(arg, "mbr") != 0)
 171                 return NULL;
 172
 173         st = xmalloc(sizeof(*st));
 174         st->ss = &mbr;
 175         st->info = NULL;
 176         st->minor_version = 0;
 177         st->max_devs = 1;
 178         st->sb = NULL;
 179         return st;
 180 }
 181
 182 #ifndef MDASSEMBLE
 183 static int validate_geometry(struct supertype *st, int level,
 184                              int layout, int raiddisks,
 185                              int *chunk, unsigned long long size,
 186                              unsigned long long data_offset,
 187                              char *subdev, unsigned long long *freesize,
 188                              int verbose)
 189 {
 190         pr_err("mbr metadata cannot be used this way\n");
 191         return 0;
 192 }
 193 #endif
 194
 195 struct superswitch mbr = {
 196 #ifndef MDASSEMBLE
 197         .examine_super = examine_mbr,
 198         .validate_geometry = validate_geometry,
 199 #endif
 200         .match_metadata_desc = match_metadata_desc,
 201         .load_super = load_super_mbr,
 202         .store_super = store_mbr,
 203         .getinfo_super = getinfo_mbr,
 204         .free_super = free_mbr,
 205         .name = "mbr",
 206 };