super-gpt.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  * 'gpt' is a pseudo metadata type for devices which have a
  28  * GPT partition table.
  29  *
  30  * Obviously arrays cannot be created or assembled for this type.
  31  * It is used to allow a new bare device to have an partition table
  32  * added so the member partitions can then be included in other
  33  * arrays as relevant.
  34  *
  35  * The meaning operations are:
  36  * examine_super, but not brief_examine_super or export_examine
  37  * load_super
  38  * store_super
  39  */
  40
  41 #include "mdadm.h"
  42 #include "part.h"
  43
  44 static void free_gpt(struct supertype *st)
  45 {
  46         free(st->sb);
  47         st->sb = NULL;
  48 }
  49
  50 static void examine_gpt(struct supertype *st, char *homehost)
  51 {
  52         struct GPT *gpt = st->sb + 512;
  53         struct GPT_part_entry *gpe = st->sb + 1024;
  54         unsigned int i;
  55
  56         printf("    GPT Magic : %llx\n", (unsigned long long)__le64_to_cpu(gpt->magic));
  57         printf(" GPT Revision : %ld\n", (long)__le32_to_cpu(gpt->revision));
  58         for (i = 0; i < __le32_to_cpu(gpt->part_cnt); i++) {
  59                 printf("  Partition[%02d] : %12llu sectors at %12llu\n",
  60                        i,
  61                        (unsigned long long)__le64_to_cpu(gpe[i].starting_lba),
  62                        (unsigned long long)__le64_to_cpu(gpe[i].ending_lba)-
  63                        (unsigned long long)__le64_to_cpu(gpe[i].starting_lba)
  64                        +1
  65                         );
  66         }
  67 }
  68
  69 static int load_gpt(struct supertype *st, int fd, char *devname)
  70 {
  71         struct MBR *super;
  72         struct GPT *gpt_head;
  73         int to_read;
  74         unsigned int sector_size;
  75
  76         free_gpt(st);
  77
  78         if (posix_memalign((void**)&super, 4096, 32*512) != 0) {
  79                 pr_err("could not allocate superblock\n");
  80                 return 1;
  81         }
  82
  83         if (!get_dev_sector_size(fd, devname, &sector_size)) {
  84                 free(super);
  85                 return 1;
  86         }
  87
  88         lseek(fd, 0, 0);
  89         if (read(fd, super, sizeof(*super)) != sizeof(*super)) {
  90         no_read:
  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             super->parts[0].part_type != MBR_GPT_PARTITION_TYPE) {
 100         not_found:
 101                 if (devname)
 102                         pr_err("No partition table found on %s\n",
 103                                 devname);
 104                 free(super);
 105                 return 1;
 106         }
 107         /* Set offset to second block (GPT header) */
 108         lseek(fd, sector_size, SEEK_SET);
 109         /* Seem to have GPT, load the header */
 110         gpt_head = (struct GPT*)(super+1);
 111         if (read(fd, gpt_head, sizeof(*gpt_head)) != sizeof(*gpt_head))
 112                 goto no_read;
 113         if (gpt_head->magic != GPT_SIGNATURE_MAGIC)
 114                 goto not_found;
 115         if (__le32_to_cpu(gpt_head->part_cnt) >= 128)
 116                 goto not_found;
 117
 118         to_read = __le32_to_cpu(gpt_head->part_cnt) * sizeof(struct GPT_part_entry);
 119         to_read =  ((to_read+511)/512) * 512;
 120         /* Set offset to third block (GPT entries) */
 121         lseek(fd, sector_size*2, SEEK_SET);
 122         if (read(fd, gpt_head+1, to_read) != to_read)
 123                 goto no_read;
 124
 125         st->sb = super;
 126
 127         if (st->ss == NULL) {
 128                 st->ss = &gpt;
 129                 st->minor_version = 0;
 130                 st->max_devs = 1;
 131                 st->info = NULL;
 132         }
 133         return 0;
 134 }
 135
 136 static int store_gpt(struct supertype *st, int fd)
 137 {
 138         /* FIXME should I save the boot loader */
 139         /* need to write two copies! */
 140         /* FIXME allow for blocks != 512 bytes
 141          *etc
 142          */
 143         struct MBR *super = st->sb;
 144         struct GPT *gpt;
 145         int to_write;
 146
 147         gpt = (struct GPT*)(super+1);
 148
 149         to_write = __le32_to_cpu(gpt->part_cnt) * sizeof(struct GPT_part_entry);
 150         to_write =  ((to_write+511)/512) * 512;
 151
 152         lseek(fd, 0, 0);
 153         if (write(fd, st->sb, to_write) != to_write)
 154                 return 4;
 155
 156         fsync(fd);
 157         ioctl(fd, BLKRRPART, 0);
 158         return 0;
 159 }
 160
 161 static void getinfo_gpt(struct supertype *st, struct mdinfo *info, char *map)
 162 {
 163         struct GPT *gpt = st->sb + 512;
 164         struct GPT_part_entry *gpe = st->sb + 1024;
 165         unsigned int i;
 166
 167         memset(&info->array, 0, sizeof(info->array));
 168         memset(&info->disk, 0, sizeof(info->disk));
 169         strcpy(info->text_version, "gpt");
 170         strcpy(info->name, "gpt");
 171         info->component_size = 0;
 172
 173         for (i = 0; i < __le32_to_cpu(gpt->part_cnt); i++) {
 174                 unsigned long long last =
 175                         (unsigned long long)__le64_to_cpu(gpe[i].ending_lba);
 176                 if (last > info->component_size)
 177                         info->component_size = last;
 178         }
 179 }
 180
 181 static struct supertype *match_metadata_desc(char *arg)
 182 {
 183         struct supertype *st = xmalloc(sizeof(*st));
 184
 185         if (!st)
 186                 return st;
 187         if (strcmp(arg, "gpt") != 0) {
 188                 free(st);
 189                 return NULL;
 190         }
 191
 192         st->ss = &gpt;
 193         st->info = NULL;
 194         st->minor_version = 0;
 195         st->max_devs = 1;
 196         st->sb = NULL;
 197         return st;
 198 }
 199
 200 static int validate_geometry(struct supertype *st, int level,
 201                              int layout, int raiddisks,
 202                              int *chunk, unsigned long long size,
 203                              unsigned long long data_offset,
 204                              char *subdev, unsigned long long *freesize,
 205                              int consistency_policy, int verbose)
 206 {
 207         pr_err("gpt metadata cannot be used this way\n");
 208         return 0;
 209 }
 210
 211 struct superswitch gpt = {
 212         .examine_super = examine_gpt,
 213         .validate_geometry = validate_geometry,
 214         .match_metadata_desc = match_metadata_desc,
 215         .load_super = load_gpt,
 216         .store_super = store_gpt,
 217         .getinfo_super = getinfo_gpt,
 218         .free_super = free_gpt,
 219         .name = "gpt",
 220 };