md-autodetect.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/syscalls.h>
#include <linux/mount.h>
#include <linux/major.h>
#include <linux/delay.h>
#include <linux/raid/detect.h>
#include <linux/raid/md_u.h>
#include <linux/raid/md_p.h>
#include "md.h"

/*
 * When md (and any require personalities) are compiled into the kernel
 * (not a module), arrays can be assembles are boot time using with AUTODETECT
 * where specially marked partitions are registered with md_autodetect_dev(),
 * and with MD_BOOT where devices to be collected are given on the boot line
 * with md=.....
 * The code for that is here.
 */

#ifdef CONFIG_MD_AUTODETECT
static int __initdata raid_noautodetect;
#else
static int __initdata raid_noautodetect=1;
#endif
static int __initdata raid_autopart;

static struct {
	int minor;
	int partitioned;
	int level;
	int chunk;
	char *device_names;
} md_setup_args[256] __initdata;

static int md_setup_ents __initdata;

/*
 * Parse the command-line parameters given our kernel, but do not
 * actually try to invoke the MD device now; that is handled by
 * md_setup_drive after the low-level disk drivers have initialised.
 *
 * 27/11/1999: Fixed to work correctly with the 2.3 kernel (which
 *             assigns the task of parsing integer arguments to the
 *             invoked program now).  Added ability to initialise all
 *             the MD devices (by specifying multiple "md=" lines)
 *             instead of just one.  -- KTK
 * 18May2000: Added support for persistent-superblock arrays:
 *             md=n,0,factor,fault,device-list   uses RAID0 for device n
 *             md=n,-1,factor,fault,device-list  uses LINEAR for device n
 *             md=n,device-list      reads a RAID superblock from the devices
 *             elements in device-list are read by name_to_kdev_t so can be
 *             a hex number or something like /dev/hda1 /dev/sdb
 * 2001-06-03: Dave Cinege <dcinege@psychosis.com>
 *		Shifted name_to_kdev_t() and related operations to md_set_drive()
 *		for later execution. Rewrote section to make devfs compatible.
 */
static int __init md_setup(char *str)
{
	int minor, level, factor, fault, partitioned = 0;
	char *pername = "";
	char *str1;
	int ent;

	if (*str == 'd') {
		partitioned = 1;
		str++;
	}
	if (get_option(&str, &minor) != 2) {	/* MD Number */
		printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
		return 0;
	}
	str1 = str;
	for (ent=0 ; ent< md_setup_ents ; ent++)
		if (md_setup_args[ent].minor == minor &&
		    md_setup_args[ent].partitioned == partitioned) {
			printk(KERN_WARNING "md: md=%s%d, Specified more than once. "
			       "Replacing previous definition.\n", partitioned?"d":"", minor);
			break;
		}
	if (ent >= ARRAY_SIZE(md_setup_args)) {
		printk(KERN_WARNING "md: md=%s%d - too many md initialisations\n", partitioned?"d":"", minor);
		return 0;
	}
	if (ent >= md_setup_ents)
		md_setup_ents++;
	switch (get_option(&str, &level)) {	/* RAID level */
	case 2: /* could be 0 or -1.. */
		if (level == 0 || level == LEVEL_LINEAR) {
			if (get_option(&str, &factor) != 2 ||	/* Chunk Size */
					get_option(&str, &fault) != 2) {
				printk(KERN_WARNING "md: Too few arguments supplied to md=.\n");
				return 0;
			}
			md_setup_args[ent].level = level;
			md_setup_args[ent].chunk = 1 << (factor+12);
			if (level ==  LEVEL_LINEAR)
				pername = "linear";
			else
				pername = "raid0";
			break;
		}
		/* FALL THROUGH */
	case 1: /* the first device is numeric */
		str = str1;
		/* FALL THROUGH */
	case 0:
		md_setup_args[ent].level = LEVEL_NONE;
		pername="super-block";
	}

	printk(KERN_INFO "md: Will configure md%d (%s) from %s, below.\n",
		minor, pername, str);
	md_setup_args[ent].device_names = str;
	md_setup_args[ent].partitioned = partitioned;
	md_setup_args[ent].minor = minor;

	return 1;
}

static inline int create_dev(char *name, dev_t dev)
{
	ksys_unlink(name);
	return ksys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
}

static void __init md_setup_drive(void)
{
	int minor, i, ent, partitioned;
	dev_t dev;
	dev_t devices[MD_SB_DISKS+1];

	for (ent = 0; ent < md_setup_ents ; ent++) {
		int fd;
		int err = 0;
		char *devname;
		mdu_disk_info_t dinfo;
		char name[16];

		minor = md_setup_args[ent].minor;
		partitioned = md_setup_args[ent].partitioned;
		devname = md_setup_args[ent].device_names;

		sprintf(name, "/dev/md%s%d", partitioned?"_d":"", minor);
		if (partitioned)
			dev = MKDEV(mdp_major, minor << MdpMinorShift);
		else
			dev = MKDEV(MD_MAJOR, minor);
		create_dev(name, dev);
		for (i = 0; i < MD_SB_DISKS && devname != NULL; i++) {
			struct kstat stat;
			char *p;
			char comp_name[64];

			p = strchr(devname, ',');
			if (p)
				*p++ = 0;

			dev = name_to_dev_t(devname);
			if (strncmp(devname, "/dev/", 5) == 0)
				devname += 5;
			snprintf(comp_name, 63, "/dev/%s", devname);
			if (vfs_stat(comp_name, &stat) == 0 &&
			    S_ISBLK(stat.mode))
				dev = new_decode_dev(stat.rdev);
			if (!dev) {
				printk(KERN_WARNING "md: Unknown device name: %s\n", devname);
				break;
			}

			devices[i] = dev;

			devname = p;
		}
		devices[i] = 0;

		if (!i)
			continue;

		printk(KERN_INFO "md: Loading md%s%d: %s\n",
			partitioned ? "_d" : "", minor,
			md_setup_args[ent].device_names);

		fd = ksys_open(name, 0, 0);
		if (fd < 0) {
			printk(KERN_ERR "md: open failed - cannot start "
					"array %s\n", name);
			continue;
		}
		if (ksys_ioctl(fd, SET_ARRAY_INFO, 0) == -EBUSY) {
			printk(KERN_WARNING
			       "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
			       minor);
			ksys_close(fd);
			continue;
		}

		if (md_setup_args[ent].level != LEVEL_NONE) {
			/* non-persistent */
			mdu_array_info_t ainfo;
			ainfo.level = md_setup_args[ent].level;
			ainfo.size = 0;
			ainfo.nr_disks =0;
			ainfo.raid_disks =0;
			while (devices[ainfo.raid_disks])
				ainfo.raid_disks++;
			ainfo.md_minor =minor;
			ainfo.not_persistent = 1;

			ainfo.state = (1 << MD_SB_CLEAN);
			ainfo.layout = 0;
			ainfo.chunk_size = md_setup_args[ent].chunk;
			err = ksys_ioctl(fd, SET_ARRAY_INFO, (long)&ainfo);
			for (i = 0; !err && i <= MD_SB_DISKS; i++) {
				dev = devices[i];
				if (!dev)
					break;
				dinfo.number = i;
				dinfo.raid_disk = i;
				dinfo.state = (1<<MD_DISK_ACTIVE)|(1<<MD_DISK_SYNC);
				dinfo.major = MAJOR(dev);
				dinfo.minor = MINOR(dev);
				err = ksys_ioctl(fd, ADD_NEW_DISK,
						 (long)&dinfo);
			}
		} else {
			/* persistent */
			for (i = 0; i <= MD_SB_DISKS; i++) {
				dev = devices[i];
				if (!dev)
					break;
				dinfo.major = MAJOR(dev);
				dinfo.minor = MINOR(dev);
				ksys_ioctl(fd, ADD_NEW_DISK, (long)&dinfo);
			}
		}
		if (!err)
			err = ksys_ioctl(fd, RUN_ARRAY, 0);
		if (err)
			printk(KERN_WARNING "md: starting md%d failed\n", minor);
		ksys_close(fd);
	}
}

static int __init raid_setup(char *str)
{
	int len, pos;

	len = strlen(str) + 1;
	pos = 0;

	while (pos < len) {
		char *comma = strchr(str+pos, ',');
		int wlen;
		if (comma)
			wlen = (comma-str)-pos;
		else	wlen = (len-1)-pos;

		if (!strncmp(str, "noautodetect", wlen))
			raid_noautodetect = 1;
		if (!strncmp(str, "autodetect", wlen))
			raid_noautodetect = 0;
		if (strncmp(str, "partitionable", wlen)==0)
			raid_autopart = 1;
		if (strncmp(str, "part", wlen)==0)
			raid_autopart = 1;
		pos += wlen+1;
	}
	return 1;
}

__setup("raid=", raid_setup);
__setup("md=", md_setup);

static void __init autodetect_raid(void)
{
	/*
	 * Since we don't want to detect and use half a raid array, we need to
	 * wait for the known devices to complete their probing
	 */
	printk(KERN_INFO "md: Waiting for all devices to be available before autodetect\n");
	printk(KERN_INFO "md: If you don't use raid, use raid=noautodetect\n");

	wait_for_device_probe();
	md_autostart_arrays(raid_autopart);
}

void __init md_run_setup(void)
{
	create_dev("/dev/md0", MKDEV(MD_MAJOR, 0));

	if (raid_noautodetect)
		printk(KERN_INFO "md: Skipping autodetection of RAID arrays. (raid=autodetect will force)\n");
	else
		autodetect_raid();
	md_setup_drive();
}