Add mbr pseudo metadata handler.
[thirdparty/mdadm.git] / 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 (st->subarray[0])
84 return 1;
85
86 if (posix_memalign((void**)&super, 512, 512) != 0) {
87 fprintf(stderr, Name ": %s could not allocate superblock\n",
88 __func__);
89 return 1;
90 }
91
92 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
93
94 lseek(fd, 0, 0);
95 if (read(fd, super, sizeof(*super)) != sizeof(*super)) {
96 if (devname)
97 fprintf(stderr, Name ": Cannot read partition table on %s\n",
98 devname);
99 free(super);
100 return 1;
101 }
102
103 if (super->magic != MBR_SIGNATURE_MAGIC) {
104 if (devname)
105 fprintf(stderr, Name ": No partition table found on %s\n",
106 devname);
107 free(super);
108 return 1;
109 }
110
111 st->sb = super;
112
113 if (st->ss == NULL) {
114 st->ss = &mbr;
115 st->minor_version = 0;
116 st->max_devs = 1;
117 st->info = NULL;
118 }
119 return 0;
120 }
121
122 static int store_mbr(struct supertype *st, int fd)
123 {
124 struct MBR *old, *super;
125
126 if (posix_memalign((void**)&old, 512, 512) != 0) {
127 fprintf(stderr, Name ": %s could not allocate superblock\n",
128 __func__);
129 return 1;
130 }
131
132 ioctl(fd, BLKFLSBUF, 0); /* make sure we read current data */
133
134 lseek(fd, 0, 0);
135 if (read(fd, old, sizeof(*old)) != sizeof(*old)) {
136 free(old);
137 return 1;
138 }
139
140 super = st->sb;
141 memcpy(super->pad, old->pad, sizeof(super->pad));
142 free(old);
143 lseek(fd, 0, 0);
144 if (write(fd, super, sizeof(*super)) != sizeof(*super))
145 return 4;
146 fsync(fd);
147 ioctl(fd, BLKRRPART, 0);
148 return 0;
149 }
150
151 static void getinfo_mbr(struct supertype *st, struct mdinfo *info)
152 {
153 struct MBR *sb = st->sb;
154 int i;
155
156 memset(&info->array, 0, sizeof(info->array));
157 memset(&info->disk, 0, sizeof(info->disk));
158 strcpy(info->text_version, "mbr");
159 strcpy(info->name, "mbr");
160 info->component_size = 0;
161
162 for (i = 0; i < MBR_PARTITIONS ; i++)
163 if (sb->parts[i].blocks_num) {
164 unsigned long last =
165 (unsigned long)__le32_to_cpu(sb->parts[i].blocks_num)
166 + (unsigned long)__le32_to_cpu(sb->parts[i].first_sect_lba);
167 if (last > info->component_size)
168 info->component_size = last;
169 }
170
171 }
172
173 static struct supertype *match_metadata_desc(char *arg)
174 {
175 struct supertype *st = malloc(sizeof(*st));
176
177 if (!st)
178 return st;
179 if (strcmp(arg, "mbr") != 0)
180 return NULL;
181
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
191 static int validate_geometry(struct supertype *st, int level,
192 int layout, int raiddisks,
193 int chunk, unsigned long long size,
194 char *subdev, unsigned long long *freesize,
195 int verbose)
196 {
197 fprintf(stderr, Name ": mbr metadata cannot be used this way\n");
198 return 0;
199 }
200 #endif
201
202 struct superswitch mbr = {
203 #ifndef MDASSEMBLE
204 .examine_super = examine_mbr,
205 #endif
206 .validate_geometry = validate_geometry,
207 .match_metadata_desc = match_metadata_desc,
208 .load_super = load_super_mbr,
209 .store_super = store_mbr,
210 .getinfo_super = getinfo_mbr,
211 .free_super = free_mbr,
212 .name = "mbr",
213 };