[linux.git] / init / do_mounts.c

// SPDX-License-Identifier: GPL-2.0-only
#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/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/ktime.h>

#include <linux/nfs_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/nfs_mount.h>
#include <linux/raid/detect.h>
#include <uapi/linux/mount.h>

#include "do_mounts.h"

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

dev_t ROOT_DEV;

static int __init load_ramdisk(char *str)
{
	pr_warn("ignoring the deprecated load_ramdisk= option\n");
	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);

static int __init root_dev_setup(char *line)
{
	strscpy(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 int __init rootwait_timeout_setup(char *str)
{
	int sec;

	if (kstrtoint(str, 0, &sec) || sec < 0) {
		pr_warn("ignoring invalid rootwait value\n");
		goto ignore;
	}

	if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) {
		pr_warn("ignoring excessive rootwait value\n");
		goto ignore;
	}

	return 1;

ignore:
	/* Fallback to indefinite wait */
	root_wait = -1;

	return 1;
}

__setup("rootwait=", rootwait_timeout_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);

/* This can return zero length strings. Caller should check */
static int __init split_fs_names(char *page, size_t size)
{
	int count = 1;
	char *p = page;

	strscpy(p, root_fs_names, size);
	while (*p++) {
		if (p[-1] == ',') {
			p[-1] = '\0';
			count++;
		}
	}

	return count;
}

static int __init do_mount_root(const char *name, const char *fs,
				 const int flags, const void *data)
{
	struct super_block *s;
	struct page *p = NULL;
	char *data_page = NULL;
	int ret;

	if (data) {
		/* init_mount() requires a full page as fifth argument */
		p = alloc_page(GFP_KERNEL);
		if (!p)
			return -ENOMEM;
		data_page = page_address(p);
		/* zero-pad. init_mount() will make sure it's terminated */
		strncpy(data_page, data, PAGE_SIZE);
	}

	ret = init_mount(name, "/root", fs, flags, data_page);
	if (ret)
		goto out;

	init_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));

out:
	if (p)
		put_page(p);
	return ret;
}

void __init mount_root_generic(char *name, char *pretty_name, int flags)
{
	struct page *page = alloc_page(GFP_KERNEL);
	char *fs_names = page_address(page);
	char *p;
	char b[BDEVNAME_SIZE];
	int num_fs, i;

	scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
		  MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
	if (root_fs_names)
		num_fs = split_fs_names(fs_names, PAGE_SIZE);
	else
		num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
retry:
	for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
		int err;

		if (!*p)
			continue;
		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
		 */
		printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
				pretty_name, b, err);
		printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
		printk_all_partitions();

		if (root_fs_names)
			num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
		if (!num_fs)
			pr_err("Can't find any bdev filesystem to be used for mount!\n");
		else {
			pr_err("List of all bdev filesystems:\n");
			for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
				pr_err(" %s", p);
			pr_err("\n");
		}

		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 (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
		printk(" %s", p);
	printk("\n");
	panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, 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 void __init mount_nfs_root(void)
{
	char *root_dev, *root_data;
	unsigned int timeout;
	int try;

	if (nfs_root_data(&root_dev, &root_data))
		goto fail;

	/*
	 * 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++) {
		if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))
			return;
		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;
	}
fail:
	pr_err("VFS: Unable to mount root fs via NFS.\n");
}
#else
static inline void mount_nfs_root(void)
{
}
#endif /* CONFIG_ROOT_NFS */

#ifdef CONFIG_CIFS_ROOT

#define CIFSROOT_TIMEOUT_MIN	5
#define CIFSROOT_TIMEOUT_MAX	30
#define CIFSROOT_RETRY_MAX	5

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

	if (cifs_root_data(&root_dev, &root_data))
		goto fail;

	timeout = CIFSROOT_TIMEOUT_MIN;
	for (try = 1; ; try++) {
		if (!do_mount_root(root_dev, "cifs", root_mountflags,
				   root_data))
			return;
		if (try > CIFSROOT_RETRY_MAX)
			break;

		ssleep(timeout);
		timeout <<= 1;
		if (timeout > CIFSROOT_TIMEOUT_MAX)
			timeout = CIFSROOT_TIMEOUT_MAX;
	}
fail:
	pr_err("VFS: Unable to mount root fs via SMB.\n");
}
#else
static inline void mount_cifs_root(void)
{
}
#endif /* CONFIG_CIFS_ROOT */

static bool __init fs_is_nodev(char *fstype)
{
	struct file_system_type *fs = get_fs_type(fstype);
	bool ret = false;

	if (fs) {
		ret = !(fs->fs_flags & FS_REQUIRES_DEV);
		put_filesystem(fs);
	}

	return ret;
}

static int __init mount_nodev_root(char *root_device_name)
{
	char *fs_names, *fstype;
	int err = -EINVAL;
	int num_fs, i;

	fs_names = (void *)__get_free_page(GFP_KERNEL);
	if (!fs_names)
		return -EINVAL;
	num_fs = split_fs_names(fs_names, PAGE_SIZE);

	for (i = 0, fstype = fs_names; i < num_fs;
	     i++, fstype += strlen(fstype) + 1) {
		if (!*fstype)
			continue;
		if (!fs_is_nodev(fstype))
			continue;
		err = do_mount_root(root_device_name, fstype, root_mountflags,
				    root_mount_data);
		if (!err)
			break;
	}

	free_page((unsigned long)fs_names);
	return err;
}

#ifdef CONFIG_BLOCK
static void __init mount_block_root(char *root_device_name)
{
	int err = create_dev("/dev/root", ROOT_DEV);

	if (err < 0)
		pr_emerg("Failed to create /dev/root: %d\n", err);
	mount_root_generic("/dev/root", root_device_name, root_mountflags);
}
#else
static inline void mount_block_root(char *root_device_name)
{
}
#endif /* CONFIG_BLOCK */

void __init mount_root(char *root_device_name)
{
	switch (ROOT_DEV) {
	case Root_NFS:
		mount_nfs_root();
		break;
	case Root_CIFS:
		mount_cifs_root();
		break;
	case Root_Generic:
		mount_root_generic(root_device_name, root_device_name,
				   root_mountflags);
		break;
	case 0:
		if (root_device_name && root_fs_names &&
		    mount_nodev_root(root_device_name) == 0)
			break;
		fallthrough;
	default:
		mount_block_root(root_device_name);
		break;
	}
}

/* wait for any asynchronous scanning to complete */
static void __init wait_for_root(char *root_device_name)
{
	ktime_t end;

	if (ROOT_DEV != 0)
		return;

	pr_info("Waiting for root device %s...\n", root_device_name);

	end = ktime_add_ms(ktime_get_raw(), root_wait);

	while (!driver_probe_done() ||
	       early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {
		msleep(5);
		if (root_wait > 0 && ktime_after(ktime_get_raw(), end))
			break;
	}

	async_synchronize_full();

}

static dev_t __init parse_root_device(char *root_device_name)
{
	int error;
	dev_t dev;

	if (!strncmp(root_device_name, "mtd", 3) ||
	    !strncmp(root_device_name, "ubi", 3))
		return Root_Generic;
	if (strcmp(root_device_name, "/dev/nfs") == 0)
		return Root_NFS;
	if (strcmp(root_device_name, "/dev/cifs") == 0)
		return Root_CIFS;
	if (strcmp(root_device_name, "/dev/ram") == 0)
		return Root_RAM0;

	error = early_lookup_bdev(root_device_name, &dev);
	if (error) {
		if (error == -EINVAL && root_wait) {
			pr_err("Disabling rootwait; root= is invalid.\n");
			root_wait = 0;
		}
		return 0;
	}
	return dev;
}

/*
 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
 */
void __init prepare_namespace(void)
{
	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_DEV = parse_root_device(saved_root_name);

	if (initrd_load(saved_root_name))
		goto out;

	if (root_wait)
		wait_for_root(saved_root_name);
	mount_root(saved_root_name);
out:
	devtmpfs_mount();
	init_mount(".", "/", NULL, MS_MOVE, NULL);
	init_chroot(".");
}

static bool is_tmpfs;
static int rootfs_init_fs_context(struct fs_context *fc)
{
	if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
		return shmem_init_fs_context(fc);

	return ramfs_init_fs_context(fc);
}

struct file_system_type rootfs_fs_type = {
	.name		= "rootfs",
	.init_fs_context = rootfs_init_fs_context,
	.kill_sb	= kill_litter_super,
};

void __init init_rootfs(void)
{
	if (IS_ENABLED(CONFIG_TMPFS)) {
		if (!saved_root_name[0] && !root_fs_names)
			is_tmpfs = true;
		else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))
			is_tmpfs = true;
	}
}
Commit	Line	Data
457c8996	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	2	#include <linux/module.h>
	3	#include <linux/sched.h>
	4	#include <linux/ctype.h>
	5	#include <linux/fd.h>
	6	#include <linux/tty.h>
	7	#include <linux/suspend.h>
	8	#include <linux/root_dev.h>
	9	#include <linux/security.h>
	10	#include <linux/delay.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>
45071e1c	21	#include <linux/ktime.h>
1da177e4 LT	22
	23	#include <linux/nfs_fs.h>
	24	#include <linux/nfs_fs_sb.h>
	25	#include <linux/nfs_mount.h>
4f5b246b	26	#include <linux/raid/detect.h>
e262e32d	27	#include <uapi/linux/mount.h>
1da177e4 LT	28
	29	#include "do_mounts.h"
	30
9b04c997	31	int root_mountflags = MS_RDONLY \| MS_SILENT;
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)
1da177e4 LT	38	{
c8376994	39	pr_warn("ignoring the deprecated load_ramdisk= option\n");
1da177e4 LT	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
1da177e4 LT	63	static int __init root_dev_setup(char *line)
1da177e4 LT	64	{
a1d3a6d9	65	strscpy(saved_root_name, line, sizeof(saved_root_name));
1da177e4 LT	66	return 1;
	67	}
	68
	69	__setup("root=", root_dev_setup);
	70
cc1ed754 PO	71	static int __init rootwait_setup(char *str)
	72	{
	73	if (*str)
	74	return 0;
45071e1c	75	root_wait = -1;
cc1ed754 PO	76	return 1;
	77	}
	78
	79	__setup("rootwait", rootwait_setup);
	80
45071e1c LP	81	static int __init rootwait_timeout_setup(char *str)
	82	{
	83	int sec;
	84
	85	if (kstrtoint(str, 0, &sec) \|\| sec < 0) {
	86	pr_warn("ignoring invalid rootwait value\n");
	87	goto ignore;
	88	}
	89
	90	if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) {
	91	pr_warn("ignoring excessive rootwait value\n");
	92	goto ignore;
	93	}
	94
	95	return 1;
	96
	97	ignore:
	98	/* Fallback to indefinite wait */
	99	root_wait = -1;
	100
	101	return 1;
	102	}
	103
	104	__setup("rootwait=", rootwait_timeout_setup);
	105
1da177e4 LT	106	static char * __initdata root_mount_data;
	107	static int __init root_data_setup(char *str)
	108	{
	109	root_mount_data = str;
	110	return 1;
	111	}
	112
	113	static char * __initdata root_fs_names;
	114	static int __init fs_names_setup(char *str)
	115	{
	116	root_fs_names = str;
	117	return 1;
	118	}
	119
	120	static unsigned int __initdata root_delay;
	121	static int __init root_delay_setup(char *str)
	122	{
	123	root_delay = simple_strtoul(str, NULL, 0);
	124	return 1;
	125	}
	126
	127	__setup("rootflags=", root_data_setup);
	128	__setup("rootfstype=", fs_names_setup);
	129	__setup("rootdelay=", root_delay_setup);
	130
b51593c4	131	/* This can return zero length strings. Caller should check */
26e293f7	132	static int __init split_fs_names(char *page, size_t size)
1da177e4	133	{
b51593c4	134	int count = 1;
6e7c1770	135	char *p = page;
1da177e4	136
a1d3a6d9	137	strscpy(p, root_fs_names, size);
6e7c1770	138	while (*p++) {
b51593c4	139	if (p[-1] == ',') {
6e7c1770	140	p[-1] = '\0';
b51593c4 VG	141	count++;
b51593c4 VG	142	}
1da177e4	143	}
e24d12b7	144
6e7c1770	145	return count;
1da177e4 LT	146	}
1da177e4 LT	147
cccaa5e3 DB	148	static int __init do_mount_root(const char name, const char fs,
cccaa5e3 DB	149	const int flags, const void *data)
1da177e4	150	{
d8c9584e	151	struct super_block *s;
7de7de7c LT	152	struct page *p = NULL;
7de7de7c LT	153	char *data_page = NULL;
cccaa5e3 DB	154	int ret;
cccaa5e3 DB	155
7de7de7c	156	if (data) {
c60166f0	157	/* init_mount() requires a full page as fifth argument */
7de7de7c LT	158	p = alloc_page(GFP_KERNEL);
	159	if (!p)
	160	return -ENOMEM;
	161	data_page = page_address(p);
c60166f0	162	/* zero-pad. init_mount() will make sure it's terminated */
7de7de7c LT	163	strncpy(data_page, data, PAGE_SIZE);
7de7de7c LT	164	}
cccaa5e3	165
c60166f0	166	ret = init_mount(name, "/root", fs, flags, data_page);
cccaa5e3 DB	167	if (ret)
cccaa5e3 DB	168	goto out;
1da177e4	169
db63f1e3	170	init_chdir("/root");
d8c9584e AV	171	s = current->fs->pwd.dentry->d_sb;
d8c9584e AV	172	ROOT_DEV = s->s_dev;
80cdc6da MSB	173	printk(KERN_INFO
80cdc6da MSB	174	"VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
d8c9584e	175	s->s_type->name,
bc98a42c	176	sb_rdonly(s) ? " readonly" : "",
d8c9584e	177	MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
cccaa5e3 DB	178
cccaa5e3 DB	179	out:
7de7de7c LT	180	if (p)
7de7de7c LT	181	put_page(p);
cccaa5e3	182	return ret;
1da177e4 LT	183	}
1da177e4 LT	184
c8643c72	185	void __init mount_root_generic(char name, char pretty_name, int flags)
1da177e4	186	{
75f296d9	187	struct page *page = alloc_page(GFP_KERNEL);
a608ca21	188	char *fs_names = page_address(page);
1da177e4 LT	189	char *p;
1da177e4 LT	190	char b[BDEVNAME_SIZE];
6e7c1770	191	int num_fs, i;
1da177e4	192
ea3edd4d CH	193	scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
ea3edd4d CH	194	MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
e24d12b7	195	if (root_fs_names)
26e293f7	196	num_fs = split_fs_names(fs_names, PAGE_SIZE);
e24d12b7	197	else
6e7c1770	198	num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
1da177e4	199	retry:
6e7c1770	200	for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
b51593c4 VG	201	int err;
	202
	203	if (!*p)
	204	continue;
	205	err = do_mount_root(name, p, flags, root_mount_data);
1da177e4 LT	206	switch (err) {
	207	case 0:
	208	goto out;
	209	case -EACCES:
1da177e4 LT	210	case -EINVAL:
	211	continue;
	212	}
	213	/*
	214	* Allow the user to distinguish between failed sys_open
	215	* and bad superblock on root device.
dd2a345f	216	* and give them a list of the available devices
1da177e4	217	*/
0e0cb892	218	printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
c8643c72	219	pretty_name, b, err);
dd2a345f	220	printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
dd2a345f	221	printk_all_partitions();
6aee6723 AC	222
	223	if (root_fs_names)
	224	num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
	225	if (!num_fs)
	226	pr_err("Can't find any bdev filesystem to be used for mount!\n");
	227	else {
	228	pr_err("List of all bdev filesystems:\n");
	229	for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
	230	pr_err(" %s", p);
	231	pr_err("\n");
	232	}
	233
1da177e4 LT	234	panic("VFS: Unable to mount root fs on %s", b);
1da177e4 LT	235	}
e462ec50 DH	236	if (!(flags & SB_RDONLY)) {
e462ec50 DH	237	flags \|= SB_RDONLY;
10975933 MS	238	goto retry;
10975933 MS	239	}
be6e028b	240
dd2a345f DG	241	printk("List of all partitions:\n");
dd2a345f DG	242	printk_all_partitions();
be6e028b	243	printk("No filesystem could mount root, tried: ");
6e7c1770	244	for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
be6e028b AW	245	printk(" %s", p);
be6e028b AW	246	printk("\n");
84d2b696	247	panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b);
1da177e4	248	out:
a608ca21	249	put_page(page);
1da177e4 LT	250	}
	251
	252	#ifdef CONFIG_ROOT_NFS
43717c7d CL	253
	254	#define NFSROOT_TIMEOUT_MIN 5
	255	#define NFSROOT_TIMEOUT_MAX 30
	256	#define NFSROOT_RETRY_MAX 5
	257
a6a41d39	258	static void __init mount_nfs_root(void)
1da177e4	259	{
56463e50	260	char root_dev, root_data;
43717c7d	261	unsigned int timeout;
a6a41d39	262	int try;
1da177e4	263
a6a41d39 CH	264	if (nfs_root_data(&root_dev, &root_data))
a6a41d39 CH	265	goto fail;
43717c7d CL	266
	267	/*
	268	* The server or network may not be ready, so try several
	269	* times. Stop after a few tries in case the client wants
	270	* to fall back to other boot methods.
	271	*/
	272	timeout = NFSROOT_TIMEOUT_MIN;
	273	for (try = 1; ; try++) {
a6a41d39 CH	274	if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))
a6a41d39 CH	275	return;
43717c7d CL	276	if (try > NFSROOT_RETRY_MAX)
	277	break;
	278
	279	/* Wait, in case the server refused us immediately */
	280	ssleep(timeout);
	281	timeout <<= 1;
	282	if (timeout > NFSROOT_TIMEOUT_MAX)
	283	timeout = NFSROOT_TIMEOUT_MAX;
	284	}
a6a41d39 CH	285	fail:
a6a41d39 CH	286	pr_err("VFS: Unable to mount root fs via NFS.\n");
1da177e4	287	}
a6a41d39 CH	288	#else
	289	static inline void mount_nfs_root(void)
	290	{
1da177e4	291	}
a6a41d39	292	#endif /* CONFIG_ROOT_NFS */
1da177e4	293
8902dd52 PAS	294	#ifdef CONFIG_CIFS_ROOT
8902dd52 PAS	295
8902dd52 PAS	296	#define CIFSROOT_TIMEOUT_MIN 5
	297	#define CIFSROOT_TIMEOUT_MAX 30
	298	#define CIFSROOT_RETRY_MAX 5
	299
a6a41d39	300	static void __init mount_cifs_root(void)
8902dd52 PAS	301	{
	302	char root_dev, root_data;
	303	unsigned int timeout;
a6a41d39	304	int try;
8902dd52	305
a6a41d39 CH	306	if (cifs_root_data(&root_dev, &root_data))
a6a41d39 CH	307	goto fail;
8902dd52 PAS	308
	309	timeout = CIFSROOT_TIMEOUT_MIN;
	310	for (try = 1; ; try++) {
a6a41d39 CH	311	if (!do_mount_root(root_dev, "cifs", root_mountflags,
	312	root_data))
	313	return;
8902dd52 PAS	314	if (try > CIFSROOT_RETRY_MAX)
	315	break;
	316
	317	ssleep(timeout);
	318	timeout <<= 1;
	319	if (timeout > CIFSROOT_TIMEOUT_MAX)
	320	timeout = CIFSROOT_TIMEOUT_MAX;
	321	}
a6a41d39 CH	322	fail:
a6a41d39 CH	323	pr_err("VFS: Unable to mount root fs via SMB.\n");
8902dd52	324	}
a6a41d39 CH	325	#else
	326	static inline void mount_cifs_root(void)
	327	{
	328	}
	329	#endif /* CONFIG_CIFS_ROOT */
8902dd52	330
f9259be6 CH	331	static bool __init fs_is_nodev(char *fstype)
	332	{
	333	struct file_system_type *fs = get_fs_type(fstype);
	334	bool ret = false;
	335
	336	if (fs) {
	337	ret = !(fs->fs_flags & FS_REQUIRES_DEV);
	338	put_filesystem(fs);
	339	}
	340
	341	return ret;
	342	}
	343
c8643c72	344	static int __init mount_nodev_root(char *root_device_name)
f9259be6 CH	345	{
	346	char fs_names, fstype;
	347	int err = -EINVAL;
6e7c1770	348	int num_fs, i;
f9259be6 CH	349
	350	fs_names = (void *)__get_free_page(GFP_KERNEL);
	351	if (!fs_names)
	352	return -EINVAL;
26e293f7	353	num_fs = split_fs_names(fs_names, PAGE_SIZE);
f9259be6	354
6e7c1770 CH	355	for (i = 0, fstype = fs_names; i < num_fs;
6e7c1770 CH	356	i++, fstype += strlen(fstype) + 1) {
b51593c4 VG	357	if (!*fstype)
b51593c4 VG	358	continue;
f9259be6 CH	359	if (!fs_is_nodev(fstype))
	360	continue;
	361	err = do_mount_root(root_device_name, fstype, root_mountflags,
	362	root_mount_data);
	363	if (!err)
	364	break;
f9259be6 CH	365	}
	366
	367	free_page((unsigned long)fs_names);
	368	return err;
	369	}
	370
9361401e	371	#ifdef CONFIG_BLOCK
c8643c72	372	static void __init mount_block_root(char *root_device_name)
1da177e4	373	{
a6a41d39 CH	374	int err = create_dev("/dev/root", ROOT_DEV);
	375
	376	if (err < 0)
	377	pr_emerg("Failed to create /dev/root: %d\n", err);
c8643c72	378	mount_root_generic("/dev/root", root_device_name, root_mountflags);
a6a41d39 CH	379	}
a6a41d39 CH	380	#else
c8643c72	381	static inline void mount_block_root(char *root_device_name)
a6a41d39 CH	382	{
	383	}
	384	#endif /* CONFIG_BLOCK */
c69e3c3a	385
c8643c72	386	void __init mount_root(char *root_device_name)
a6a41d39 CH	387	{
	388	switch (ROOT_DEV) {
	389	case Root_NFS:
	390	mount_nfs_root();
	391	break;
	392	case Root_CIFS:
	393	mount_cifs_root();
	394	break;
07d63cbb CH	395	case Root_Generic:
	396	mount_root_generic(root_device_name, root_device_name,
	397	root_mountflags);
	398	break;
a6a41d39	399	case 0:
c8643c72 CH	400	if (root_device_name && root_fs_names &&
c8643c72 CH	401	mount_nodev_root(root_device_name) == 0)
a6a41d39 CH	402	break;
	403	fallthrough;
	404	default:
c8643c72	405	mount_block_root(root_device_name);
a6a41d39	406	break;
1da177e4	407	}
1da177e4 LT	408	}
1da177e4 LT	409
3701c600 CH	410	/* wait for any asynchronous scanning to complete */
	411	static void __init wait_for_root(char *root_device_name)
	412	{
45071e1c LP	413	ktime_t end;
45071e1c LP	414
3701c600	415	if (ROOT_DEV != 0)
c8376994	416	return;
c69e3c3a	417
3701c600 CH	418	pr_info("Waiting for root device %s...\n", root_device_name);
3701c600 CH	419
45071e1c LP	420	end = ktime_add_ms(ktime_get_raw(), root_wait);
45071e1c LP	421
cf056a43	422	while (!driver_probe_done() \|\|
45071e1c	423	early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {
3701c600	424	msleep(5);
45071e1c LP	425	if (root_wait > 0 && ktime_after(ktime_get_raw(), end))
	426	break;
	427	}
	428
3701c600 CH	429	async_synchronize_full();
	430
	431	}
	432
07d63cbb CH	433	static dev_t __init parse_root_device(char *root_device_name)
07d63cbb CH	434	{
079caa35	435	int error;
cf056a43 CH	436	dev_t dev;
cf056a43 CH	437
07d63cbb CH	438	if (!strncmp(root_device_name, "mtd", 3) \|\|
	439	!strncmp(root_device_name, "ubi", 3))
	440	return Root_Generic;
c0c1a7dc CH	441	if (strcmp(root_device_name, "/dev/nfs") == 0)
	442	return Root_NFS;
	443	if (strcmp(root_device_name, "/dev/cifs") == 0)
	444	return Root_CIFS;
	445	if (strcmp(root_device_name, "/dev/ram") == 0)
	446	return Root_RAM0;
cf056a43	447
079caa35 CH	448	error = early_lookup_bdev(root_device_name, &dev);
	449	if (error) {
	450	if (error == -EINVAL && root_wait) {
	451	pr_err("Disabling rootwait; root= is invalid.\n");
	452	root_wait = 0;
	453	}
cf056a43	454	return 0;
c69e3c3a	455	}
cf056a43	456	return dev;
1da177e4 LT	457	}
	458
	459	/*
	460	* Prepare the namespace - decide what/where to mount, load ramdisks, etc.
	461	*/
	462	void __init prepare_namespace(void)
	463	{
1da177e4	464	if (root_delay) {
ca75b4d8	465	printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
1da177e4 LT	466	root_delay);
	467	ssleep(root_delay);
	468	}
	469
216773a7 AV	470	/*
	471	* wait for the known devices to complete their probing
	472	*
	473	* Note: this is a potential source of long boot delays.
	474	* For example, it is not atypical to wait 5 seconds here
	475	* for the touchpad of a laptop to initialize.
	476	*/
	477	wait_for_device_probe();
d779249e	478
1da177e4 LT	479	md_run_setup();
1da177e4 LT	480
07d63cbb CH	481	if (saved_root_name[0])
07d63cbb CH	482	ROOT_DEV = parse_root_device(saved_root_name);
1da177e4	483
73231b58	484	if (initrd_load(saved_root_name))
1da177e4 LT	485	goto out;
1da177e4 LT	486
3701c600 CH	487	if (root_wait)
3701c600 CH	488	wait_for_root(saved_root_name);
73231b58	489	mount_root(saved_root_name);
1da177e4	490	out:
5e787dbf	491	devtmpfs_mount();
c60166f0	492	init_mount(".", "/", NULL, MS_MOVE, NULL);
4b7ca501	493	init_chroot(".");
1da177e4	494	}
57f150a5	495
6e19eded	496	static bool is_tmpfs;
f3235626	497	static int rootfs_init_fs_context(struct fs_context *fc)
57f150a5	498	{
6e19eded	499	if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
f3235626	500	return shmem_init_fs_context(fc);
6e19eded	501
f3235626	502	return ramfs_init_fs_context(fc);
57f150a5 RL	503	}
57f150a5 RL	504
fd3e007f	505	struct file_system_type rootfs_fs_type = {
57f150a5	506	.name = "rootfs",
f3235626	507	.init_fs_context = rootfs_init_fs_context,
57f150a5 RL	508	.kill_sb = kill_litter_super,
	509	};
	510
037f11b4	511	void __init init_rootfs(void)
57f150a5	512	{
21528c69 SB	513	if (IS_ENABLED(CONFIG_TMPFS)) {
	514	if (!saved_root_name[0] && !root_fs_names)
	515	is_tmpfs = true;
	516	else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))
	517	is_tmpfs = true;
	518	}
57f150a5	519	}