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Add failfast support.
[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 /*
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 */
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
76 static 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
88 if (posix_memalign((void**)&super, 512, 512) != 0) {
89 pr_err("could not allocate superblock\n");
90 return 1;
91 }
92
93 lseek(fd, 0, 0);
94 if (read(fd, super, sizeof(*super)) != sizeof(*super)) {
95 if (devname)
96 pr_err("Cannot read partition table on %s\n",
97 devname);
98 free(super);
99 return 1;
100 }
101
102 if (super->magic != MBR_SIGNATURE_MAGIC) {
103 if (devname)
104 pr_err("No partition table found on %s\n",
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
121 static int store_mbr(struct supertype *st, int fd)
122 {
123 struct MBR *old, *super;
124
125 if (posix_memalign((void**)&old, 512, 512) != 0) {
126 pr_err("could not allocate superblock\n");
127 return 1;
128 }
129
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
147 static void getinfo_mbr(struct supertype *st, struct mdinfo *info, char *map)
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++)
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 */
164 if (sb->parts[i].blocks_num) {
165 unsigned long last =
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
174 static struct supertype *match_metadata_desc(char *arg)
175 {
176 struct supertype *st;
177
178 if (strcmp(arg, "mbr") != 0)
179 return NULL;
180
181 st = xmalloc(sizeof(*st));
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 unsigned long long data_offset,
195 char *subdev, unsigned long long *freesize,
196 int verbose)
197 {
198 pr_err("mbr metadata cannot be used this way\n");
199 return 0;
200 }
201 #endif
202
203 struct superswitch mbr = {
204 #ifndef MDASSEMBLE
205 .examine_super = examine_mbr,
206 .validate_geometry = validate_geometry,
207 #endif
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 };