[linux-2.6-block.git] / init / do_mounts.c

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/ctype.h>
#include <linux/fd.h>
#include <linux/tty.h>
#include <linux/suspend.h>
#include <linux/root_dev.h>
#include <linux/security.h>
#include <linux/delay.h>
#include <linux/genhd.h>
#include <linux/mount.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/initrd.h>
#include <linux/async.h>
#include <linux/fs_struct.h>
#include <linux/slab.h>
#include <linux/ramfs.h>
#include <linux/shmem_fs.h>

#include <linux/nfs_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/nfs_mount.h>

#include "do_mounts.h"

int __initdata rd_doload;	/* 1 = load RAM disk, 0 = don't load */

int root_mountflags = MS_RDONLY | MS_SILENT;
static char * __initdata root_device_name;
static char __initdata saved_root_name[64];
static int root_wait;

dev_t ROOT_DEV;

static int __init load_ramdisk(char *str)
{
	rd_doload = simple_strtol(str,NULL,0) & 3;
	return 1;
}
__setup("load_ramdisk=", load_ramdisk);

static int __init readonly(char *str)
{
	if (*str)
		return 0;
	root_mountflags |= MS_RDONLY;
	return 1;
}

static int __init readwrite(char *str)
{
	if (*str)
		return 0;
	root_mountflags &= ~MS_RDONLY;
	return 1;
}

__setup("ro", readonly);
__setup("rw", readwrite);

#ifdef CONFIG_BLOCK
struct uuidcmp {
	const char *uuid;
	int len;
};

/**
 * match_dev_by_uuid - callback for finding a partition using its uuid
 * @dev:	device passed in by the caller
 * @data:	opaque pointer to the desired struct uuidcmp to match
 *
 * Returns 1 if the device matches, and 0 otherwise.
 */
static int match_dev_by_uuid(struct device *dev, const void *data)
{
	const struct uuidcmp *cmp = data;
	struct hd_struct *part = dev_to_part(dev);

	if (!part->info)
		goto no_match;

	if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
		goto no_match;

	return 1;
no_match:
	return 0;
}


/**
 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
 * @uuid_str:	char array containing ascii UUID
 *
 * The function will return the first partition which contains a matching
 * UUID value in its partition_meta_info struct.  This does not search
 * by filesystem UUIDs.
 *
 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
 * extracted and used as an offset from the partition identified by the UUID.
 *
 * Returns the matching dev_t on success or 0 on failure.
 */
static dev_t devt_from_partuuid(const char *uuid_str)
{
	dev_t res = 0;
	struct uuidcmp cmp;
	struct device *dev = NULL;
	struct gendisk *disk;
	struct hd_struct *part;
	int offset = 0;
	bool clear_root_wait = false;
	char *slash;

	cmp.uuid = uuid_str;

	slash = strchr(uuid_str, '/');
	/* Check for optional partition number offset attributes. */
	if (slash) {
		char c = 0;
		/* Explicitly fail on poor PARTUUID syntax. */
		if (sscanf(slash + 1,
			   "PARTNROFF=%d%c", &offset, &c) != 1) {
			clear_root_wait = true;
			goto done;
		}
		cmp.len = slash - uuid_str;
	} else {
		cmp.len = strlen(uuid_str);
	}

	if (!cmp.len) {
		clear_root_wait = true;
		goto done;
	}

	dev = class_find_device(&block_class, NULL, &cmp,
				&match_dev_by_uuid);
	if (!dev)
		goto done;

	res = dev->devt;

	/* Attempt to find the partition by offset. */
	if (!offset)
		goto no_offset;

	res = 0;
	disk = part_to_disk(dev_to_part(dev));
	part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
	if (part) {
		res = part_devt(part);
		put_device(part_to_dev(part));
	}

no_offset:
	put_device(dev);
done:
	if (clear_root_wait) {
		pr_err("VFS: PARTUUID= is invalid.\n"
		       "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
		if (root_wait)
			pr_err("Disabling rootwait; root= is invalid.\n");
		root_wait = 0;
	}
	return res;
}
#endif

/*
 *	Convert a name into device number.  We accept the following variants:
 *
 *	1) <hex_major><hex_minor> device number in hexadecimal represents itself
 *         no leading 0x, for example b302.
 *	2) /dev/nfs represents Root_NFS (0xff)
 *	3) /dev/<disk_name> represents the device number of disk
 *	4) /dev/<disk_name><decimal> represents the device number
 *         of partition - device number of disk plus the partition number
 *	5) /dev/<disk_name>p<decimal> - same as the above, that form is
 *	   used when disk name of partitioned disk ends on a digit.
 *	6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
 *	   unique id of a partition if the partition table provides it.
 *	   The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
 *	   partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
 *	   filled hex representation of the 32-bit "NT disk signature", and PP
 *	   is a zero-filled hex representation of the 1-based partition number.
 *	7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
 *	   a partition with a known unique id.
 *	8) <major>:<minor> major and minor number of the device separated by
 *	   a colon.
 *
 *	If name doesn't have fall into the categories above, we return (0,0).
 *	block_class is used to check if something is a disk name. If the disk
 *	name contains slashes, the device name has them replaced with
 *	bangs.
 */

dev_t name_to_dev_t(const char *name)
{
	char s[32];
	char *p;
	dev_t res = 0;
	int part;

#ifdef CONFIG_BLOCK
	if (strncmp(name, "PARTUUID=", 9) == 0) {
		name += 9;
		res = devt_from_partuuid(name);
		if (!res)
			goto fail;
		goto done;
	}
#endif

	if (strncmp(name, "/dev/", 5) != 0) {
		unsigned maj, min, offset;
		char dummy;

		if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
		    (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
			res = MKDEV(maj, min);
			if (maj != MAJOR(res) || min != MINOR(res))
				goto fail;
		} else {
			res = new_decode_dev(simple_strtoul(name, &p, 16));
			if (*p)
				goto fail;
		}
		goto done;
	}

	name += 5;
	res = Root_NFS;
	if (strcmp(name, "nfs") == 0)
		goto done;
	res = Root_RAM0;
	if (strcmp(name, "ram") == 0)
		goto done;

	if (strlen(name) > 31)
		goto fail;
	strcpy(s, name);
	for (p = s; *p; p++)
		if (*p == '/')
			*p = '!';
	res = blk_lookup_devt(s, 0);
	if (res)
		goto done;

	/*
	 * try non-existent, but valid partition, which may only exist
	 * after revalidating the disk, like partitioned md devices
	 */
	while (p > s && isdigit(p[-1]))
		p--;
	if (p == s || !*p || *p == '0')
		goto fail;

	/* try disk name without <part number> */
	part = simple_strtoul(p, NULL, 10);
	*p = '\0';
	res = blk_lookup_devt(s, part);
	if (res)
		goto done;

	/* try disk name without p<part number> */
	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
		goto fail;
	p[-1] = '\0';
	res = blk_lookup_devt(s, part);
	if (res)
		goto done;

fail:
	return 0;
done:
	return res;
}
EXPORT_SYMBOL_GPL(name_to_dev_t);

static int __init root_dev_setup(char *line)
{
	strlcpy(saved_root_name, line, sizeof(saved_root_name));
	return 1;
}

__setup("root=", root_dev_setup);

static int __init rootwait_setup(char *str)
{
	if (*str)
		return 0;
	root_wait = 1;
	return 1;
}

__setup("rootwait", rootwait_setup);

static char * __initdata root_mount_data;
static int __init root_data_setup(char *str)
{
	root_mount_data = str;
	return 1;
}

static char * __initdata root_fs_names;
static int __init fs_names_setup(char *str)
{
	root_fs_names = str;
	return 1;
}

static unsigned int __initdata root_delay;
static int __init root_delay_setup(char *str)
{
	root_delay = simple_strtoul(str, NULL, 0);
	return 1;
}

__setup("rootflags=", root_data_setup);
__setup("rootfstype=", fs_names_setup);
__setup("rootdelay=", root_delay_setup);

static void __init get_fs_names(char *page)
{
	char *s = page;

	if (root_fs_names) {
		strcpy(page, root_fs_names);
		while (*s++) {
			if (s[-1] == ',')
				s[-1] = '\0';
		}
	} else {
		int len = get_filesystem_list(page);
		char *p, *next;

		page[len] = '\0';
		for (p = page-1; p; p = next) {
			next = strchr(++p, '\n');
			if (*p++ != '\t')
				continue;
			while ((*s++ = *p++) != '\n')
				;
			s[-1] = '\0';
		}
	}
	*s = '\0';
}

static int __init do_mount_root(char *name, char *fs, int flags, void *data)
{
	struct super_block *s;
	int err = ksys_mount(name, "/root", fs, flags, data);
	if (err)
		return err;

	ksys_chdir("/root");
	s = current->fs->pwd.dentry->d_sb;
	ROOT_DEV = s->s_dev;
	printk(KERN_INFO
	       "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
	       s->s_type->name,
	       sb_rdonly(s) ? " readonly" : "",
	       MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
	return 0;
}

void __init mount_block_root(char *name, int flags)
{
	struct page *page = alloc_page(GFP_KERNEL);
	char *fs_names = page_address(page);
	char *p;
#ifdef CONFIG_BLOCK
	char b[BDEVNAME_SIZE];
#else
	const char *b = name;
#endif

	get_fs_names(fs_names);
retry:
	for (p = fs_names; *p; p += strlen(p)+1) {
		int err = do_mount_root(name, p, flags, root_mount_data);
		switch (err) {
			case 0:
				goto out;
			case -EACCES:
			case -EINVAL:
				continue;
		}
	        /*
		 * Allow the user to distinguish between failed sys_open
		 * and bad superblock on root device.
		 * and give them a list of the available devices
		 */
#ifdef CONFIG_BLOCK
		__bdevname(ROOT_DEV, b);
#endif
		printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
				root_device_name, b, err);
		printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");

		printk_all_partitions();
#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
		printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
		       "explicit textual name for \"root=\" boot option.\n");
#endif
		panic("VFS: Unable to mount root fs on %s", b);
	}
	if (!(flags & SB_RDONLY)) {
		flags |= SB_RDONLY;
		goto retry;
	}

	printk("List of all partitions:\n");
	printk_all_partitions();
	printk("No filesystem could mount root, tried: ");
	for (p = fs_names; *p; p += strlen(p)+1)
		printk(" %s", p);
	printk("\n");
#ifdef CONFIG_BLOCK
	__bdevname(ROOT_DEV, b);
#endif
	panic("VFS: Unable to mount root fs on %s", b);
out:
	put_page(page);
}
 
#ifdef CONFIG_ROOT_NFS

#define NFSROOT_TIMEOUT_MIN	5
#define NFSROOT_TIMEOUT_MAX	30
#define NFSROOT_RETRY_MAX	5

static int __init mount_nfs_root(void)
{
	char *root_dev, *root_data;
	unsigned int timeout;
	int try, err;

	err = nfs_root_data(&root_dev, &root_data);
	if (err != 0)
		return 0;

	/*
	 * The server or network may not be ready, so try several
	 * times.  Stop after a few tries in case the client wants
	 * to fall back to other boot methods.
	 */
	timeout = NFSROOT_TIMEOUT_MIN;
	for (try = 1; ; try++) {
		err = do_mount_root(root_dev, "nfs",
					root_mountflags, root_data);
		if (err == 0)
			return 1;
		if (try > NFSROOT_RETRY_MAX)
			break;

		/* Wait, in case the server refused us immediately */
		ssleep(timeout);
		timeout <<= 1;
		if (timeout > NFSROOT_TIMEOUT_MAX)
			timeout = NFSROOT_TIMEOUT_MAX;
	}
	return 0;
}
#endif

#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
void __init change_floppy(char *fmt, ...)
{
	struct termios termios;
	char buf[80];
	char c;
	int fd;
	va_list args;
	va_start(args, fmt);
	vsprintf(buf, fmt, args);
	va_end(args);
	fd = ksys_open("/dev/root", O_RDWR | O_NDELAY, 0);
	if (fd >= 0) {
		ksys_ioctl(fd, FDEJECT, 0);
		ksys_close(fd);
	}
	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
	fd = ksys_open("/dev/console", O_RDWR, 0);
	if (fd >= 0) {
		ksys_ioctl(fd, TCGETS, (long)&termios);
		termios.c_lflag &= ~ICANON;
		ksys_ioctl(fd, TCSETSF, (long)&termios);
		ksys_read(fd, &c, 1);
		termios.c_lflag |= ICANON;
		ksys_ioctl(fd, TCSETSF, (long)&termios);
		ksys_close(fd);
	}
}
#endif

void __init mount_root(void)
{
#ifdef CONFIG_ROOT_NFS
	if (ROOT_DEV == Root_NFS) {
		if (mount_nfs_root())
			return;

		printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
		ROOT_DEV = Root_FD0;
	}
#endif
#ifdef CONFIG_BLK_DEV_FD
	if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
		/* rd_doload is 2 for a dual initrd/ramload setup */
		if (rd_doload==2) {
			if (rd_load_disk(1)) {
				ROOT_DEV = Root_RAM1;
				root_device_name = NULL;
			}
		} else
			change_floppy("root floppy");
	}
#endif
#ifdef CONFIG_BLOCK
	{
		int err = create_dev("/dev/root", ROOT_DEV);

		if (err < 0)
			pr_emerg("Failed to create /dev/root: %d\n", err);
		mount_block_root("/dev/root", root_mountflags);
	}
#endif
}

/*
 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 */
void __init prepare_namespace(void)
{
	int is_floppy;

	if (root_delay) {
		printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
		       root_delay);
		ssleep(root_delay);
	}

	/*
	 * wait for the known devices to complete their probing
	 *
	 * Note: this is a potential source of long boot delays.
	 * For example, it is not atypical to wait 5 seconds here
	 * for the touchpad of a laptop to initialize.
	 */
	wait_for_device_probe();

	md_run_setup();

	if (saved_root_name[0]) {
		root_device_name = saved_root_name;
		if (!strncmp(root_device_name, "mtd", 3) ||
		    !strncmp(root_device_name, "ubi", 3)) {
			mount_block_root(root_device_name, root_mountflags);
			goto out;
		}
		ROOT_DEV = name_to_dev_t(root_device_name);
		if (strncmp(root_device_name, "/dev/", 5) == 0)
			root_device_name += 5;
	}

	if (initrd_load())
		goto out;

	/* wait for any asynchronous scanning to complete */
	if ((ROOT_DEV == 0) && root_wait) {
		printk(KERN_INFO "Waiting for root device %s...\n",
			saved_root_name);
		while (driver_probe_done() != 0 ||
			(ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
			msleep(5);
		async_synchronize_full();
	}

	is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;

	if (is_floppy && rd_doload && rd_load_disk(0))
		ROOT_DEV = Root_RAM0;

	mount_root();
out:
	devtmpfs_mount("dev");
	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
	ksys_chroot(".");
}

static bool is_tmpfs;
static struct dentry *rootfs_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	static unsigned long once;
	void *fill = ramfs_fill_super;

	if (test_and_set_bit(0, &once))
		return ERR_PTR(-ENODEV);

	if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
		fill = shmem_fill_super;

	return mount_nodev(fs_type, flags, data, fill);
}

static struct file_system_type rootfs_fs_type = {
	.name		= "rootfs",
	.mount		= rootfs_mount,
	.kill_sb	= kill_litter_super,
};

int __init init_rootfs(void)
{
	int err = register_filesystem(&rootfs_fs_type);

	if (err)
		return err;

	if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
		(!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
		err = shmem_init();
		is_tmpfs = true;
	} else {
		err = init_ramfs_fs();
	}

	if (err)
		unregister_filesystem(&rootfs_fs_type);

	return err;
}
Commit	Line	Data
1da177e4 LT	1	#include <linux/module.h>
	2	#include <linux/sched.h>
	3	#include <linux/ctype.h>
	4	#include <linux/fd.h>
	5	#include <linux/tty.h>
	6	#include <linux/suspend.h>
	7	#include <linux/root_dev.h>
	8	#include <linux/security.h>
	9	#include <linux/delay.h>
dd2a345f	10	#include <linux/genhd.h>
d53d9f16	11	#include <linux/mount.h>
d779249e	12	#include <linux/device.h>
46595390	13	#include <linux/init.h>
011e3fcd	14	#include <linux/fs.h>
82c8253a	15	#include <linux/initrd.h>
22a9d645	16	#include <linux/async.h>
5ad4e53b	17	#include <linux/fs_struct.h>
5a0e3ad6	18	#include <linux/slab.h>
57f150a5	19	#include <linux/ramfs.h>
16203a7a	20	#include <linux/shmem_fs.h>
1da177e4 LT	21
	22	#include <linux/nfs_fs.h>
	23	#include <linux/nfs_fs_sb.h>
	24	#include <linux/nfs_mount.h>
	25
	26	#include "do_mounts.h"
	27
1da177e4 LT	28	int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
1da177e4 LT	29
9b04c997	30	int root_mountflags = MS_RDONLY \| MS_SILENT;
f56f6d30	31	static char * __initdata root_device_name;
1da177e4	32	static char __initdata saved_root_name[64];
79975f13	33	static int root_wait;
1da177e4	34
1da177e4 LT	35	dev_t ROOT_DEV;
1da177e4 LT	36
1da177e4 LT	37	static int __init load_ramdisk(char *str)
	38	{
	39	rd_doload = simple_strtol(str,NULL,0) & 3;
	40	return 1;
	41	}
	42	__setup("load_ramdisk=", load_ramdisk);
	43
	44	static int __init readonly(char *str)
	45	{
	46	if (*str)
	47	return 0;
	48	root_mountflags \|= MS_RDONLY;
	49	return 1;
	50	}
	51
	52	static int __init readwrite(char *str)
	53	{
	54	if (*str)
	55	return 0;
	56	root_mountflags &= ~MS_RDONLY;
	57	return 1;
	58	}
	59
	60	__setup("ro", readonly);
	61	__setup("rw", readwrite);
	62
6d0aed7a	63	#ifdef CONFIG_BLOCK
1ad7e899 SW	64	struct uuidcmp {
	65	const char *uuid;
	66	int len;
	67	};
	68
b5af921e WD	69	/**
	70	* match_dev_by_uuid - callback for finding a partition using its uuid
	71	* @dev: device passed in by the caller
1ad7e899	72	* @data: opaque pointer to the desired struct uuidcmp to match
b5af921e WD	73	*
	74	* Returns 1 if the device matches, and 0 otherwise.
	75	*/
9f3b795a	76	static int match_dev_by_uuid(struct device dev, const void data)
b5af921e	77	{
9f3b795a	78	const struct uuidcmp *cmp = data;
b5af921e WD	79	struct hd_struct *part = dev_to_part(dev);
	80
	81	if (!part->info)
	82	goto no_match;
	83
1ad7e899 SW	84	if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
1ad7e899 SW	85	goto no_match;
b5af921e WD	86
	87	return 1;
	88	no_match:
	89	return 0;
	90	}
	91
	92
	93	/**
	94	* devt_from_partuuid - looks up the dev_t of a partition by its UUID
a68b3108	95	* @uuid_str: char array containing ascii UUID
b5af921e WD	96	*
	97	* The function will return the first partition which contains a matching
	98	* UUID value in its partition_meta_info struct. This does not search
	99	* by filesystem UUIDs.
	100	*
a68b3108	101	* If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
79975f13 WD	102	* extracted and used as an offset from the partition identified by the UUID.
79975f13 WD	103	*
b5af921e WD	104	* Returns the matching dev_t on success or 0 on failure.
b5af921e WD	105	*/
1ad7e899	106	static dev_t devt_from_partuuid(const char *uuid_str)
b5af921e WD	107	{
b5af921e WD	108	dev_t res = 0;
1ad7e899	109	struct uuidcmp cmp;
b5af921e	110	struct device *dev = NULL;
79975f13 WD	111	struct gendisk *disk;
	112	struct hd_struct *part;
	113	int offset = 0;
283f8fc0 SW	114	bool clear_root_wait = false;
283f8fc0 SW	115	char *slash;
79975f13	116
1ad7e899	117	cmp.uuid = uuid_str;
1ad7e899	118
283f8fc0	119	slash = strchr(uuid_str, '/');
79975f13	120	/* Check for optional partition number offset attributes. */
283f8fc0	121	if (slash) {
79975f13 WD	122	char c = 0;
79975f13 WD	123	/* Explicitly fail on poor PARTUUID syntax. */
283f8fc0 SW	124	if (sscanf(slash + 1,
	125	"PARTNROFF=%d%c", &offset, &c) != 1) {
	126	clear_root_wait = true;
79975f13 WD	127	goto done;
79975f13 WD	128	}
283f8fc0 SW	129	cmp.len = slash - uuid_str;
	130	} else {
	131	cmp.len = strlen(uuid_str);
	132	}
	133
	134	if (!cmp.len) {
	135	clear_root_wait = true;
	136	goto done;
79975f13	137	}
b5af921e	138
1ad7e899 SW	139	dev = class_find_device(&block_class, NULL, &cmp,
1ad7e899 SW	140	&match_dev_by_uuid);
b5af921e WD	141	if (!dev)
	142	goto done;
	143
	144	res = dev->devt;
b5af921e	145
79975f13 WD	146	/* Attempt to find the partition by offset. */
	147	if (!offset)
	148	goto no_offset;
	149
	150	res = 0;
	151	disk = part_to_disk(dev_to_part(dev));
	152	part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
	153	if (part) {
	154	res = part_devt(part);
	155	put_device(part_to_dev(part));
	156	}
	157
	158	no_offset:
	159	put_device(dev);
b5af921e	160	done:
283f8fc0 SW	161	if (clear_root_wait) {
	162	pr_err("VFS: PARTUUID= is invalid.\n"
	163	"Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
	164	if (root_wait)
	165	pr_err("Disabling rootwait; root= is invalid.\n");
	166	root_wait = 0;
	167	}
b5af921e WD	168	return res;
b5af921e WD	169	}
6d0aed7a	170	#endif
b5af921e	171
1da177e4 LT	172	/*
	173	* Convert a name into device number. We accept the following variants:
	174	*
0bf37ae4 PM	175	* 1) <hex_major><hex_minor> device number in hexadecimal represents itself
0bf37ae4 PM	176	* no leading 0x, for example b302.
1da177e4 LT	177	* 2) /dev/nfs represents Root_NFS (0xff)
	178	* 3) /dev/<disk_name> represents the device number of disk
	179	* 4) /dev/<disk_name><decimal> represents the device number
	180	* of partition - device number of disk plus the partition number
	181	* 5) /dev/<disk_name>p<decimal> - same as the above, that form is
	182	* used when disk name of partitioned disk ends on a digit.
b5af921e WD	183	* 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
b5af921e WD	184	* unique id of a partition if the partition table provides it.
d33b98fc SW	185	* The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
	186	* partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
	187	* filled hex representation of the 32-bit "NT disk signature", and PP
	188	* is a zero-filled hex representation of the 1-based partition number.
79975f13 WD	189	* 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
79975f13 WD	190	* a partition with a known unique id.
6c251611 SC	191	* 8) <major>:<minor> major and minor number of the device separated by
6c251611 SC	192	* a colon.
1da177e4	193	*
edfaa7c3 KS	194	* If name doesn't have fall into the categories above, we return (0,0).
	195	* block_class is used to check if something is a disk name. If the disk
	196	* name contains slashes, the device name has them replaced with
	197	* bangs.
1da177e4 LT	198	*/
1da177e4 LT	199
e6e20a7a	200	dev_t name_to_dev_t(const char *name)
1da177e4 LT	201	{
	202	char s[32];
	203	char *p;
	204	dev_t res = 0;
30f2f0eb	205	int part;
1da177e4	206
6d0aed7a	207	#ifdef CONFIG_BLOCK
b5af921e WD	208	if (strncmp(name, "PARTUUID=", 9) == 0) {
b5af921e WD	209	name += 9;
b5af921e WD	210	res = devt_from_partuuid(name);
	211	if (!res)
	212	goto fail;
	213	goto done;
	214	}
6d0aed7a	215	#endif
b5af921e	216
1da177e4	217	if (strncmp(name, "/dev/", 5) != 0) {
cb31ef48	218	unsigned maj, min, offset;
283e7ad0	219	char dummy;
1da177e4	220
cb31ef48 CY	221	if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) \|\|
cb31ef48 CY	222	(sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
1da177e4 LT	223	res = MKDEV(maj, min);
	224	if (maj != MAJOR(res) \|\| min != MINOR(res))
	225	goto fail;
	226	} else {
	227	res = new_decode_dev(simple_strtoul(name, &p, 16));
	228	if (*p)
	229	goto fail;
	230	}
	231	goto done;
	232	}
edfaa7c3	233
1da177e4 LT	234	name += 5;
	235	res = Root_NFS;
	236	if (strcmp(name, "nfs") == 0)
	237	goto done;
	238	res = Root_RAM0;
	239	if (strcmp(name, "ram") == 0)
	240	goto done;
	241
	242	if (strlen(name) > 31)
	243	goto fail;
	244	strcpy(s, name);
	245	for (p = s; *p; p++)
	246	if (*p == '/')
	247	*p = '!';
30f2f0eb KS	248	res = blk_lookup_devt(s, 0);
	249	if (res)
	250	goto done;
	251
	252	/*
25985edc	253	* try non-existent, but valid partition, which may only exist
30f2f0eb KS	254	* after revalidating the disk, like partitioned md devices
	255	*/
	256	while (p > s && isdigit(p[-1]))
	257	p--;
	258	if (p == s \|\| !p \|\| p == '0')
	259	goto fail;
	260
	261	/* try disk name without <part number> */
	262	part = simple_strtoul(p, NULL, 10);
	263	*p = '\0';
	264	res = blk_lookup_devt(s, part);
	265	if (res)
	266	goto done;
	267
	268	/* try disk name without p<part number> */
	269	if (p < s + 2 \|\| !isdigit(p[-2]) \|\| p[-1] != 'p')
	270	goto fail;
	271	p[-1] = '\0';
	272	res = blk_lookup_devt(s, part);
1da177e4 LT	273	if (res)
	274	goto done;
	275
edfaa7c3 KS	276	fail:
edfaa7c3 KS	277	return 0;
1da177e4	278	done:
1da177e4	279	return res;
1da177e4	280	}
e6e20a7a	281	EXPORT_SYMBOL_GPL(name_to_dev_t);
1da177e4 LT	282
	283	static int __init root_dev_setup(char *line)
	284	{
	285	strlcpy(saved_root_name, line, sizeof(saved_root_name));
	286	return 1;
	287	}
	288
	289	__setup("root=", root_dev_setup);
	290
cc1ed754 PO	291	static int __init rootwait_setup(char *str)
	292	{
	293	if (*str)
	294	return 0;
	295	root_wait = 1;
	296	return 1;
	297	}
	298
	299	__setup("rootwait", rootwait_setup);
	300
1da177e4 LT	301	static char * __initdata root_mount_data;
	302	static int __init root_data_setup(char *str)
	303	{
	304	root_mount_data = str;
	305	return 1;
	306	}
	307
	308	static char * __initdata root_fs_names;
	309	static int __init fs_names_setup(char *str)
	310	{
	311	root_fs_names = str;
	312	return 1;
	313	}
	314
	315	static unsigned int __initdata root_delay;
	316	static int __init root_delay_setup(char *str)
	317	{
	318	root_delay = simple_strtoul(str, NULL, 0);
	319	return 1;
	320	}
	321
	322	__setup("rootflags=", root_data_setup);
	323	__setup("rootfstype=", fs_names_setup);
	324	__setup("rootdelay=", root_delay_setup);
	325
	326	static void __init get_fs_names(char *page)
	327	{
	328	char *s = page;
	329
	330	if (root_fs_names) {
	331	strcpy(page, root_fs_names);
	332	while (*s++) {
	333	if (s[-1] == ',')
	334	s[-1] = '\0';
	335	}
	336	} else {
	337	int len = get_filesystem_list(page);
	338	char p, next;
	339
	340	page[len] = '\0';
	341	for (p = page-1; p; p = next) {
	342	next = strchr(++p, '\n');
	343	if (*p++ != '\t')
	344	continue;
	345	while ((s++ = p++) != '\n')
	346	;
	347	s[-1] = '\0';
	348	}
	349	}
	350	*s = '\0';
	351	}
	352
	353	static int __init do_mount_root(char name, char fs, int flags, void *data)
	354	{
d8c9584e	355	struct super_block *s;
312db1aa	356	int err = ksys_mount(name, "/root", fs, flags, data);
1da177e4 LT	357	if (err)
	358	return err;
	359
447016e9	360	ksys_chdir("/root");
d8c9584e AV	361	s = current->fs->pwd.dentry->d_sb;
d8c9584e AV	362	ROOT_DEV = s->s_dev;
80cdc6da MSB	363	printk(KERN_INFO
80cdc6da MSB	364	"VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
d8c9584e	365	s->s_type->name,
bc98a42c	366	sb_rdonly(s) ? " readonly" : "",
d8c9584e	367	MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
1da177e4 LT	368	return 0;
	369	}
	370
	371	void __init mount_block_root(char *name, int flags)
	372	{
75f296d9	373	struct page *page = alloc_page(GFP_KERNEL);
a608ca21	374	char *fs_names = page_address(page);
1da177e4	375	char *p;
9361401e	376	#ifdef CONFIG_BLOCK
1da177e4	377	char b[BDEVNAME_SIZE];
9361401e DH	378	#else
	379	const char *b = name;
	380	#endif
1da177e4 LT	381
	382	get_fs_names(fs_names);
	383	retry:
	384	for (p = fs_names; *p; p += strlen(p)+1) {
	385	int err = do_mount_root(name, p, flags, root_mount_data);
	386	switch (err) {
	387	case 0:
	388	goto out;
	389	case -EACCES:
1da177e4 LT	390	case -EINVAL:
	391	continue;
	392	}
	393	/*
	394	* Allow the user to distinguish between failed sys_open
	395	* and bad superblock on root device.
dd2a345f	396	* and give them a list of the available devices
1da177e4	397	*/
9361401e	398	#ifdef CONFIG_BLOCK
1da177e4	399	__bdevname(ROOT_DEV, b);
9361401e	400	#endif
0e0cb892 BW	401	printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
0e0cb892 BW	402	root_device_name, b, err);
dd2a345f	403	printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
1da177e4	404
dd2a345f	405	printk_all_partitions();
55dc7db7 TH	406	#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
	407	printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
	408	"explicit textual name for \"root=\" boot option.\n");
	409	#endif
1da177e4 LT	410	panic("VFS: Unable to mount root fs on %s", b);
1da177e4 LT	411	}
e462ec50 DH	412	if (!(flags & SB_RDONLY)) {
e462ec50 DH	413	flags \|= SB_RDONLY;
10975933 MS	414	goto retry;
10975933 MS	415	}
be6e028b	416
dd2a345f DG	417	printk("List of all partitions:\n");
dd2a345f DG	418	printk_all_partitions();
be6e028b AW	419	printk("No filesystem could mount root, tried: ");
	420	for (p = fs_names; *p; p += strlen(p)+1)
	421	printk(" %s", p);
	422	printk("\n");
9361401e DH	423	#ifdef CONFIG_BLOCK
	424	__bdevname(ROOT_DEV, b);
	425	#endif
	426	panic("VFS: Unable to mount root fs on %s", b);
1da177e4	427	out:
a608ca21	428	put_page(page);
1da177e4 LT	429	}
	430
	431	#ifdef CONFIG_ROOT_NFS
43717c7d CL	432
	433	#define NFSROOT_TIMEOUT_MIN 5
	434	#define NFSROOT_TIMEOUT_MAX 30
	435	#define NFSROOT_RETRY_MAX 5
	436
1da177e4 LT	437	static int __init mount_nfs_root(void)
1da177e4 LT	438	{
56463e50	439	char root_dev, root_data;
43717c7d CL	440	unsigned int timeout;
43717c7d CL	441	int try, err;
1da177e4	442
43717c7d CL	443	err = nfs_root_data(&root_dev, &root_data);
43717c7d CL	444	if (err != 0)
56463e50	445	return 0;
43717c7d CL	446
	447	/*
	448	* The server or network may not be ready, so try several
	449	* times. Stop after a few tries in case the client wants
	450	* to fall back to other boot methods.
	451	*/
	452	timeout = NFSROOT_TIMEOUT_MIN;
	453	for (try = 1; ; try++) {
	454	err = do_mount_root(root_dev, "nfs",
	455	root_mountflags, root_data);
	456	if (err == 0)
	457	return 1;
	458	if (try > NFSROOT_RETRY_MAX)
	459	break;
	460
	461	/* Wait, in case the server refused us immediately */
	462	ssleep(timeout);
	463	timeout <<= 1;
	464	if (timeout > NFSROOT_TIMEOUT_MAX)
	465	timeout = NFSROOT_TIMEOUT_MAX;
	466	}
	467	return 0;
1da177e4 LT	468	}
	469	#endif
	470
	471	#if defined(CONFIG_BLK_DEV_RAM) \|\| defined(CONFIG_BLK_DEV_FD)
	472	void __init change_floppy(char *fmt, ...)
	473	{
	474	struct termios termios;
	475	char buf[80];
	476	char c;
	477	int fd;
	478	va_list args;
	479	va_start(args, fmt);
	480	vsprintf(buf, fmt, args);
	481	va_end(args);
bae217ea	482	fd = ksys_open("/dev/root", O_RDWR \| O_NDELAY, 0);
1da177e4	483	if (fd >= 0) {
cbb60b92	484	ksys_ioctl(fd, FDEJECT, 0);
2ca2a09d	485	ksys_close(fd);
1da177e4 LT	486	}
1da177e4 LT	487	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
bae217ea	488	fd = ksys_open("/dev/console", O_RDWR, 0);
1da177e4	489	if (fd >= 0) {
cbb60b92	490	ksys_ioctl(fd, TCGETS, (long)&termios);
1da177e4	491	termios.c_lflag &= ~ICANON;
cbb60b92	492	ksys_ioctl(fd, TCSETSF, (long)&termios);
3ce4a7bf	493	ksys_read(fd, &c, 1);
1da177e4	494	termios.c_lflag \|= ICANON;
cbb60b92	495	ksys_ioctl(fd, TCSETSF, (long)&termios);
2ca2a09d	496	ksys_close(fd);
1da177e4 LT	497	}
	498	}
	499	#endif
	500
	501	void __init mount_root(void)
	502	{
	503	#ifdef CONFIG_ROOT_NFS
377485f6	504	if (ROOT_DEV == Root_NFS) {
1da177e4 LT	505	if (mount_nfs_root())
	506	return;
	507
	508	printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
	509	ROOT_DEV = Root_FD0;
	510	}
	511	#endif
	512	#ifdef CONFIG_BLK_DEV_FD
	513	if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
	514	/* rd_doload is 2 for a dual initrd/ramload setup */
	515	if (rd_doload==2) {
	516	if (rd_load_disk(1)) {
	517	ROOT_DEV = Root_RAM1;
	518	root_device_name = NULL;
	519	}
	520	} else
	521	change_floppy("root floppy");
	522	}
	523	#endif
9361401e	524	#ifdef CONFIG_BLOCK
c69e3c3a VPS	525	{
	526	int err = create_dev("/dev/root", ROOT_DEV);
	527
	528	if (err < 0)
	529	pr_emerg("Failed to create /dev/root: %d\n", err);
	530	mount_block_root("/dev/root", root_mountflags);
	531	}
9361401e	532	#endif
1da177e4 LT	533	}
	534
	535	/*
	536	* Prepare the namespace - decide what/where to mount, load ramdisks, etc.
	537	*/
	538	void __init prepare_namespace(void)
	539	{
	540	int is_floppy;
	541
1da177e4	542	if (root_delay) {
ca75b4d8	543	printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
1da177e4 LT	544	root_delay);
	545	ssleep(root_delay);
	546	}
	547
216773a7 AV	548	/*
	549	* wait for the known devices to complete their probing
	550	*
	551	* Note: this is a potential source of long boot delays.
	552	* For example, it is not atypical to wait 5 seconds here
	553	* for the touchpad of a laptop to initialize.
	554	*/
	555	wait_for_device_probe();
d779249e	556
1da177e4 LT	557	md_run_setup();
	558
	559	if (saved_root_name[0]) {
	560	root_device_name = saved_root_name;
2d62f488 AH	561	if (!strncmp(root_device_name, "mtd", 3) \|\|
2d62f488 AH	562	!strncmp(root_device_name, "ubi", 3)) {
e9482b43 JE	563	mount_block_root(root_device_name, root_mountflags);
	564	goto out;
	565	}
1da177e4 LT	566	ROOT_DEV = name_to_dev_t(root_device_name);
	567	if (strncmp(root_device_name, "/dev/", 5) == 0)
	568	root_device_name += 5;
	569	}
	570
1da177e4 LT	571	if (initrd_load())
	572	goto out;
	573
cc1ed754 PO	574	/* wait for any asynchronous scanning to complete */
	575	if ((ROOT_DEV == 0) && root_wait) {
	576	printk(KERN_INFO "Waiting for root device %s...\n",
	577	saved_root_name);
	578	while (driver_probe_done() != 0 \|\|
	579	(ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
39a0e975	580	msleep(5);
216773a7	581	async_synchronize_full();
cc1ed754 PO	582	}
	583
	584	is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
	585
1da177e4 LT	586	if (is_floppy && rd_doload && rd_load_disk(0))
	587	ROOT_DEV = Root_RAM0;
	588
	589	mount_root();
	590	out:
2b2af54a	591	devtmpfs_mount("dev");
312db1aa	592	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
a16fe33a	593	ksys_chroot(".");
1da177e4	594	}
57f150a5	595
6e19eded	596	static bool is_tmpfs;
57f150a5 RL	597	static struct dentry rootfs_mount(struct file_system_type fs_type,
	598	int flags, const char dev_name, void data)
	599	{
	600	static unsigned long once;
6e19eded	601	void *fill = ramfs_fill_super;
57f150a5 RL	602
	603	if (test_and_set_bit(0, &once))
	604	return ERR_PTR(-ENODEV);
	605
6e19eded RL	606	if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
	607	fill = shmem_fill_super;
	608
	609	return mount_nodev(fs_type, flags, data, fill);
57f150a5 RL	610	}
	611
	612	static struct file_system_type rootfs_fs_type = {
	613	.name = "rootfs",
	614	.mount = rootfs_mount,
	615	.kill_sb = kill_litter_super,
	616	};
	617
	618	int __init init_rootfs(void)
	619	{
	620	int err = register_filesystem(&rootfs_fs_type);
	621
	622	if (err)
	623	return err;
	624
6e19eded RL	625	if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
6e19eded RL	626	(!root_fs_names \|\| strstr(root_fs_names, "tmpfs"))) {
16203a7a	627	err = shmem_init();
6e19eded RL	628	is_tmpfs = true;
6e19eded RL	629	} else {
16203a7a	630	err = init_ramfs_fs();
6e19eded	631	}
16203a7a	632
57f150a5 RL	633	if (err)
	634	unregister_filesystem(&rootfs_fs_type);
	635
	636	return err;
	637	}