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[thirdparty/mdadm.git] / super-mbr.c
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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
45static void free_mbr(struct supertype *st)
46{
47 free(st->sb);
48 st->sb = NULL;
49}
50
51#ifndef MDASSEMBLE
52
53static 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++)
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60 /*
61 * Have to make every access through sb rather than using a
62 * pointer to the partition table (or an entry), since the
63 * entries are not properly aligned.
64 */
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65 if (sb->parts[i].blocks_num)
66 printf("Partition[%d] : %12lu sectors at %12lu (type %02x)\n",
67 i,
68 (unsigned long)__le32_to_cpu(sb->parts[i].blocks_num),
69 (unsigned long)__le32_to_cpu(sb->parts[i].first_sect_lba),
70 sb->parts[i].part_type);
71
72}
73
74#endif /*MDASSEMBLE */
75
76static int load_super_mbr(struct supertype *st, int fd, char *devname)
77{
78 /* try to read an mbr
79 * Return
80 * 0 on success
81 * 1 cannot get record
82 * 2 record is meaningless
83 */
84 struct MBR *super;
85
86 free_mbr(st);
87
0f22b998 88 if (posix_memalign((void**)&super, 512, 512) != 0) {
1ade5cc1 89 pr_err("could not allocate superblock\n");
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90 return 1;
91 }
92
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93 lseek(fd, 0, 0);
94 if (read(fd, super, sizeof(*super)) != sizeof(*super)) {
95 if (devname)
e7b84f9d 96 pr_err("Cannot read partition table on %s\n",
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97 devname);
98 free(super);
99 return 1;
100 }
1011e834 101
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102 if (super->magic != MBR_SIGNATURE_MAGIC) {
103 if (devname)
e7b84f9d 104 pr_err("No partition table found on %s\n",
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105 devname);
106 free(super);
107 return 1;
108 }
109
110 st->sb = super;
111
112 if (st->ss == NULL) {
113 st->ss = &mbr;
114 st->minor_version = 0;
115 st->max_devs = 1;
116 st->info = NULL;
117 }
118 return 0;
119}
120
121static int store_mbr(struct supertype *st, int fd)
122{
123 struct MBR *old, *super;
124
125 if (posix_memalign((void**)&old, 512, 512) != 0) {
1ade5cc1 126 pr_err("could not allocate superblock\n");
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127 return 1;
128 }
129
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130 lseek(fd, 0, 0);
131 if (read(fd, old, sizeof(*old)) != sizeof(*old)) {
132 free(old);
133 return 1;
134 }
135
136 super = st->sb;
137 memcpy(super->pad, old->pad, sizeof(super->pad));
138 free(old);
139 lseek(fd, 0, 0);
140 if (write(fd, super, sizeof(*super)) != sizeof(*super))
141 return 4;
142 fsync(fd);
143 ioctl(fd, BLKRRPART, 0);
144 return 0;
145}
146
a5d85af7 147static void getinfo_mbr(struct supertype *st, struct mdinfo *info, char *map)
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148{
149 struct MBR *sb = st->sb;
150 int i;
151
152 memset(&info->array, 0, sizeof(info->array));
153 memset(&info->disk, 0, sizeof(info->disk));
154 strcpy(info->text_version, "mbr");
155 strcpy(info->name, "mbr");
156 info->component_size = 0;
157
158 for (i = 0; i < MBR_PARTITIONS ; i++)
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159 /*
160 * Have to make every access through sb rather than using a
161 * pointer to the partition table (or an entry), since the
162 * entries are not properly aligned.
163 */
0f22b998 164 if (sb->parts[i].blocks_num) {
1011e834 165 unsigned long last =
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166 (unsigned long)__le32_to_cpu(sb->parts[i].blocks_num)
167 + (unsigned long)__le32_to_cpu(sb->parts[i].first_sect_lba);
168 if (last > info->component_size)
169 info->component_size = last;
170 }
171
172}
173
174static struct supertype *match_metadata_desc(char *arg)
175{
62f5838f 176 struct supertype *st;
0f22b998 177
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178 if (strcmp(arg, "mbr") != 0)
179 return NULL;
180
503975b9 181 st = xmalloc(sizeof(*st));
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182 st->ss = &mbr;
183 st->info = NULL;
184 st->minor_version = 0;
185 st->max_devs = 1;
186 st->sb = NULL;
187 return st;
188}
189
190#ifndef MDASSEMBLE
191static int validate_geometry(struct supertype *st, int level,
192 int layout, int raiddisks,
c21e737b 193 int *chunk, unsigned long long size,
af4348dd 194 unsigned long long data_offset,
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195 char *subdev, unsigned long long *freesize,
196 int verbose)
197{
e7b84f9d 198 pr_err("mbr metadata cannot be used this way\n");
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199 return 0;
200}
201#endif
202
203struct superswitch mbr = {
204#ifndef MDASSEMBLE
205 .examine_super = examine_mbr,
0f22b998 206 .validate_geometry = validate_geometry,
71204a50 207#endif
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208 .match_metadata_desc = match_metadata_desc,
209 .load_super = load_super_mbr,
210 .store_super = store_mbr,
211 .getinfo_super = getinfo_mbr,
212 .free_super = free_mbr,
213 .name = "mbr",
214};