1// SPDX-License-Identifier: GPL-2.0
2#include <linux/kernel.h>
3#include <linux/blkdev.h>
4#include <linux/init.h>
5#include <linux/mount.h>
6#include <linux/major.h>
7#include <linux/delay.h>
8#include <linux/init_syscalls.h>
9#include <linux/raid/detect.h>
10#include <linux/raid/md_u.h>
11#include <linux/raid/md_p.h>
12#include "md.h"
13
14/*
15 * When md (and any require personalities) are compiled into the kernel
16 * (not a module), arrays can be assembles are boot time using with AUTODETECT
17 * where specially marked partitions are registered with md_autodetect_dev(),
18 * and with MD_BOOT where devices to be collected are given on the boot line
19 * with md=.....
20 * The code for that is here.
21 */
22
23#ifdef CONFIG_MD_AUTODETECT
24static int __initdata raid_noautodetect;
25#else
26static int __initdata raid_noautodetect=1;
27#endif
28static int __initdata raid_autopart;
29
30static struct md_setup_args {
31 int minor;
32 int partitioned;
33 int level;
34 int chunk;
35 char *device_names;
36} md_setup_args[256] __initdata;
37
38static int md_setup_ents __initdata;
39
40/*
41 * Parse the command-line parameters given our kernel, but do not
42 * actually try to invoke the MD device now; that is handled by
43 * md_setup_drive after the low-level disk drivers have initialised.
44 *
45 * 27/11/1999: Fixed to work correctly with the 2.3 kernel (which
46 * assigns the task of parsing integer arguments to the
47 * invoked program now). Added ability to initialise all
48 * the MD devices (by specifying multiple "md=" lines)
49 * instead of just one. -- KTK
50 * 18May2000: Added support for persistent-superblock arrays:
51 * md=n,0,factor,fault,device-list uses RAID0 for device n
52 * md=n,device-list reads a RAID superblock from the devices
53 * elements in device-list are read by name_to_kdev_t so can be
54 * a hex number or something like /dev/hda1 /dev/sdb
55 * 2001-06-03: Dave Cinege <dcinege@psychosis.com>
56 * Shifted name_to_kdev_t() and related operations to md_set_drive()
57 * for later execution. Rewrote section to make devfs compatible.
58 */
59static int __init md_setup(char *str)
60{
61 int minor, level, factor, fault, partitioned = 0;
62 char *pername = "";
63 char *str1;
64 int ent;
65
66 if (*str == 'd') {
67 partitioned = 1;
68 str++;
69 }
70 if (get_option(str: &str, pint: &minor) != 2) { /* MD Number */
71 printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
72 return 0;
73 }
74 str1 = str;
75 for (ent=0 ; ent< md_setup_ents ; ent++)
76 if (md_setup_args[ent].minor == minor &&
77 md_setup_args[ent].partitioned == partitioned) {
78 printk(KERN_WARNING "md: md=%s%d, Specified more than once. "
79 "Replacing previous definition.\n", partitioned?"d":"", minor);
80 break;
81 }
82 if (ent >= ARRAY_SIZE(md_setup_args)) {
83 printk(KERN_WARNING "md: md=%s%d - too many md initialisations\n", partitioned?"d":"", minor);
84 return 0;
85 }
86 if (ent >= md_setup_ents)
87 md_setup_ents++;
88 switch (get_option(str: &str, pint: &level)) { /* RAID level */
89 case 2: /* could be 0 or -1.. */
90 if (level == 0) {
91 if (get_option(str: &str, pint: &factor) != 2 || /* Chunk Size */
92 get_option(str: &str, pint: &fault) != 2) {
93 printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
94 return 0;
95 }
96 md_setup_args[ent].level = level;
97 md_setup_args[ent].chunk = 1 << (factor+12);
98 pername = "raid0";
99 break;
100 }
101 fallthrough;
102 case 1: /* the first device is numeric */
103 str = str1;
104 fallthrough;
105 case 0:
106 md_setup_args[ent].level = LEVEL_NONE;
107 pername="super-block";
108 }
109
110 printk(KERN_INFO "md: Will configure md%d (%s) from %s, below.\n",
111 minor, pername, str);
112 md_setup_args[ent].device_names = str;
113 md_setup_args[ent].partitioned = partitioned;
114 md_setup_args[ent].minor = minor;
115
116 return 1;
117}
118
119static void __init md_setup_drive(struct md_setup_args *args)
120{
121 char *devname = args->device_names;
122 dev_t devices[MD_SB_DISKS + 1], mdev;
123 struct mdu_array_info_s ainfo = { };
124 struct mddev *mddev;
125 int err = 0, i;
126 char name[16];
127
128 if (args->partitioned) {
129 mdev = MKDEV(mdp_major, args->minor << MdpMinorShift);
130 sprintf(buf: name, fmt: "md_d%d", args->minor);
131 } else {
132 mdev = MKDEV(MD_MAJOR, args->minor);
133 sprintf(buf: name, fmt: "md%d", args->minor);
134 }
135
136 for (i = 0; i < MD_SB_DISKS && devname != NULL; i++) {
137 struct kstat stat;
138 char *p;
139 char comp_name[64];
140 dev_t dev;
141
142 p = strchr(devname, ',');
143 if (p)
144 *p++ = 0;
145
146 if (early_lookup_bdev(pathname: devname, dev: &dev))
147 dev = 0;
148 if (strncmp(devname, "/dev/", 5) == 0)
149 devname += 5;
150 snprintf(buf: comp_name, size: 63, fmt: "/dev/%s", devname);
151 if (init_stat(filename: comp_name, stat: &stat, flags: 0) == 0 && S_ISBLK(stat.mode))
152 dev = new_decode_dev(dev: stat.rdev);
153 if (!dev) {
154 pr_warn("md: Unknown device name: %s\n", devname);
155 break;
156 }
157
158 devices[i] = dev;
159 devname = p;
160 }
161 devices[i] = 0;
162
163 if (!i)
164 return;
165
166 pr_info("md: Loading %s: %s\n", name, args->device_names);
167
168 mddev = md_alloc(dev: mdev, name);
169 if (IS_ERR(ptr: mddev)) {
170 pr_err("md: md_alloc failed - cannot start array %s\n", name);
171 return;
172 }
173
174 err = mddev_suspend_and_lock(mddev);
175 if (err) {
176 pr_err("md: failed to lock array %s\n", name);
177 goto out_mddev_put;
178 }
179
180 if (!list_empty(head: &mddev->disks) || mddev->raid_disks) {
181 pr_warn("md: Ignoring %s, already autodetected. (Use raid=noautodetect)\n",
182 name);
183 goto out_unlock;
184 }
185
186 if (args->level != LEVEL_NONE) {
187 /* non-persistent */
188 ainfo.level = args->level;
189 ainfo.md_minor = args->minor;
190 ainfo.not_persistent = 1;
191 ainfo.state = (1 << MD_SB_CLEAN);
192 ainfo.chunk_size = args->chunk;
193 while (devices[ainfo.raid_disks])
194 ainfo.raid_disks++;
195 }
196
197 err = md_set_array_info(mddev, info: &ainfo);
198
199 for (i = 0; i <= MD_SB_DISKS && devices[i]; i++) {
200 struct mdu_disk_info_s dinfo = {
201 .major = MAJOR(devices[i]),
202 .minor = MINOR(devices[i]),
203 };
204
205 if (args->level != LEVEL_NONE) {
206 dinfo.number = i;
207 dinfo.raid_disk = i;
208 dinfo.state =
209 (1 << MD_DISK_ACTIVE) | (1 << MD_DISK_SYNC);
210 }
211
212 md_add_new_disk(mddev, info: &dinfo);
213 }
214
215 if (!err)
216 err = do_md_run(mddev);
217 if (err)
218 pr_warn("md: starting %s failed\n", name);
219out_unlock:
220 mddev_unlock_and_resume(mddev);
221out_mddev_put:
222 mddev_put(mddev);
223}
224
225static int __init raid_setup(char *str)
226{
227 int len, pos;
228
229 len = strlen(str) + 1;
230 pos = 0;
231
232 while (pos < len) {
233 char *comma = strchr(str+pos, ',');
234 int wlen;
235 if (comma)
236 wlen = (comma-str)-pos;
237 else wlen = (len-1)-pos;
238
239 if (!strncmp(str, "noautodetect", wlen))
240 raid_noautodetect = 1;
241 if (!strncmp(str, "autodetect", wlen))
242 raid_noautodetect = 0;
243 if (strncmp(str, "partitionable", wlen)==0)
244 raid_autopart = 1;
245 if (strncmp(str, "part", wlen)==0)
246 raid_autopart = 1;
247 pos += wlen+1;
248 }
249 return 1;
250}
251
252__setup("raid=", raid_setup);
253__setup("md=", md_setup);
254
255static void __init autodetect_raid(void)
256{
257 /*
258 * Since we don't want to detect and use half a raid array, we need to
259 * wait for the known devices to complete their probing
260 */
261 printk(KERN_INFO "md: Waiting for all devices to be available before autodetect\n");
262 printk(KERN_INFO "md: If you don't use raid, use raid=noautodetect\n");
263
264 wait_for_device_probe();
265 md_autostart_arrays(part: raid_autopart);
266}
267
268void __init md_run_setup(void)
269{
270 int ent;
271
272 if (raid_noautodetect)
273 printk(KERN_INFO "md: Skipping autodetection of RAID arrays. (raid=autodetect will force)\n");
274 else
275 autodetect_raid();
276
277 for (ent = 0; ent < md_setup_ents; ent++)
278 md_setup_drive(args: &md_setup_args[ent]);
279}
280

source code of linux/drivers/md/md-autodetect.c