Re: VFS: Cannot open root device "304" or hda4

Re: VFS: Cannot open root device "304" or hda4

[jorge kernel]

>From: Cédric Barboiron <ced2ml@ifrance.com>
>To: kernel_286@hotmail.com
>Subject: Re: VFS: Cannot open root device "304" or hda4
>Date: Fri, 01 Aug 2003 17:27:12 +0200

Hi  Cédric,

[cut]
>Did you enable correct Partition Type Support ?

I think the config file is OK because I've only set the partition types I 
need and I always used (My root fs is ext3):

CONFIG_EXT2_FS=y
CONFIG_EXT2_FS_XATTR=y
# CONFIG_EXT2_FS_POSIX_ACL is not set
# CONFIG_EXT2_FS_SECURITY is not set
CONFIG_EXT3_FS=y   <-------
CONFIG_EXT3_FS_XATTR=y   <-------
CONFIG_EXT3_FS_POSIX_ACL=y   <-------
# CONFIG_EXT3_FS_SECURITY is not set
CONFIG_JBD=y    <-------
CONFIG_JBD_DEBUG=y   <------
CONFIG_FS_MBCACHE=y
CONFIG_REISERFS_FS=y
# CONFIG_REISERFS_CHECK is not set
# CONFIG_REISERFS_PROC_INFO is not set
# CONFIG_JFS_FS is not set
CONFIG_FS_POSIX_ACL=y
# CONFIG_XFS_FS is not set
# CONFIG_MINIX_FS is not set
# CONFIG_ROMFS_FS is not set
CONFIG_QUOTA=y
# CONFIG_QFMT_V1 is not set
# CONFIG_QFMT_V2 is not set
CONFIG_QUOTACTL=y
# CONFIG_AUTOFS_FS is not set
CONFIG_AUTOFS4_FS=y

I've even tried using initrd, but when 2.6 start, I see that it can't load 
any initrd image: unfortunatly I've create it with 'mkinitrd -o 
/boot/initrd-2.6-t2 /lib/modules/linux-2.6-test2'...

									Mario

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Re: VFS: Cannot open root device "304" or hda4

[jorge kernel]

>From: Burton Windle <bwindle@fint.org>
>To: kernel_286@hotmail.com
>Subject: Re: VFS: Cannot open root device "304" or hda4
>Date: Fri, 1 Aug 2003 11:36:01 -0400 (EDT)

Hi Burton,

>Are you sure that you compiled in support for your IDE controller and file
>system type?

Mmm..
My hardware config consists in an Acer 272Xv with sis chipset 650 (I read it 
in 2.4.21 and previous dmesg).
I think that config file is OK because when 2.6 starts, I can see something 
about "SIS961 chipset MUTIOL", and in the .config file I've set 
CONFIG_BLK_DEV_SIS5513=y that I always used for previous kernels.

						Mario
>
>--
>Burton Windle                           burton@fint.org
>Linux: the "grim reaper of innocent orphaned children."
>           from /usr/src/linux-2.4.18/init/main.c:461
>

_________________________________________________________________
Nuovo MSN Messenger 6.0 con sfondi e giochi! http://messenger.msn.it/ 
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Re: VFS: Cannot open root device "304" or hda4

[Cédric]

kernel_286@hotmail.com wrote:
> Hi to all, this is my first post on LKML.
> 
> I'm trying 2.6.0-test2-mm2 and the compiling process ends with no errors 
> except for some warnings about oss modules.
> After reboot with the 2.6 I obtain a kernel panic error:
> 
> **************************************
> VFS: Cannot open root device "304" or hda4
> Please append a correct "root=" boot option
> VFS: Unable to mount root fs on hda4;
> **************************************
> I've read old ML posts but the don't help me. 
> According to 2.4.21, the root fs is /dev/hda4: I've tried to give "root=0304" 
> or "root=/dev/hda4" at the 2.6, but I obtain the same errors.
> I've even tried initrd with no changes.
> 
> I've introduced some printk in init/do_mount.c (see the linked file at line 
> 64) and before the kernel panic, the result was :
> 
> ***************************************
> name hda4 - /sys/block/hda4/dev
> descriptor -1
> 
> name hda - /sys/block/hda/dev
> descriptor 0
> 
> scanning '3:0'
> ***************************************
> 
> Is it normal?
> 
> Thanks a lot.
> 			Mario
> 
> PS: sorry for my 'bad' english.. I'm learning...
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> #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/nfs_fs.h>
> #include <linux/nfs_fs_sb.h>
> #include <linux/nfs_mount.h>
> 
> #include "do_mounts.h"
> 
> extern int get_filesystem_list(char * buf);
> 
> int __initdata rd_doload;	/* 1 = load RAM disk, 0 = don't load */
> 
> int root_mountflags = MS_RDONLY | MS_VERBOSE;
> char * __initdata root_device_name;
> static char __initdata saved_root_name[64];
> 
> /* this is initialized in init/main.c */
> 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);
> 
> static dev_t __init try_name(char *name, int part)
> {
> 	char path[64];
> 	char buf[32];
> 	int range;
> 	dev_t res;
> 	char *s;
> 	int len;
> 	int fd;
> 	unsigned int maj, min;
> 
> 	/* read device number from .../dev */
> 
> 	sprintf(path, "/sys/block/%s/dev", name);
> 	printk("name %s - path %s\n",name, path);
> 	fd = open(path, 0, 0);
> 	printk("descriptor %d\n",fd);
> 	if (fd < 0)
> 		goto fail;
> 	len = read(fd, buf, 32);
> 	close(fd);
> 	if (len <= 0 || len == 32 || buf[len - 1] != '\n')
> 		goto fail;
> 	buf[len - 1] = '\0';
> 	/*
> 	 * The format of dev is now %u:%u -- see print_dev_t()
> 	 */
> 	printk("scanning `%s'\n", buf);
> 	if (sscanf(buf, "%u:%u", &maj, &min) == 2)
> 		res = MKDEV(maj, min);
> 	else
> 		goto fail;
> 
> 	/* if it's there and we are not looking for a partition - that's it */
> 	if (!part)
> 		return res;
> 
> 	/* otherwise read range from .../range */
> 	sprintf(path, "/sys/block/%s/range", name);
> 	fd = open(path, 0, 0);
> 	if (fd < 0)
> 		goto fail;
> 	len = read(fd, buf, 32);
> 	close(fd);
> 	if (len <= 0 || len == 32 || buf[len - 1] != '\n')
> 		goto fail;
> 	buf[len - 1] = '\0';
> 	range = simple_strtoul(buf, &s, 10);
> 	if (*s)
> 		goto fail;
> 
> 	/* if partition is within range - we got it */
> 	if (part < range)
> 		return res + part;
> fail:
> 	return (dev_t) 0;
> }
> 
> /*
>  *	Convert a name into device number.  We accept the following variants:
>  *
>  *	1) device number in hexadecimal	represents itself
>  *	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.
>  *
>  *	If name doesn't have fall into the categories above, we return 0.
>  *	Driverfs is used to check if something is a disk name - it has
>  *	all known disks under bus/block/devices.  If the disk name
>  *	contains slashes, name of driverfs node has them replaced with
>  *	dots.  try_name() does the actual checks, assuming that driverfs
>  *	is mounted on rootfs /sys.
>  */
> 
> dev_t name_to_dev_t(char *name)
> {
> 	char s[32];
> 	char *p;
> 	dev_t res = 0;
> 	int part;
> 
> 	sys_mkdir("/sys", 0700);
> 	if (sys_mount("sysfs", "/sys", "sysfs", 0, NULL) < 0)
> 		goto out;
> 
> 	if (strncmp(name, "/dev/", 5) != 0) {
> 		res = (dev_t) simple_strtoul(name, &p, 16);
> 		if (*p)
> 			goto fail;
> 		goto done;
> 	}
> 	name += 5;
> 	res = Root_NFS;
> 	if (strcmp(name, "nfs") == 0)
> 		goto done;
> 
> 	if (strlen(name) > 31)
> 		goto fail;
> 	strcpy(s, name);
> 	for (p = s; *p; p++)
> 		if (*p == '/')
> 			*p = '.';
> 	res = try_name(s, 0);
> 	if (res)
> 		goto done;
> 
> 	while (p > s && isdigit(p[-1]))
> 		p--;
> 	if (p == s || !*p || *p == '0')
> 		goto fail;
> 	part = simple_strtoul(p, NULL, 10);
> 	*p = '\0';
> 	res = try_name(s, part);
> 	if (res)
> 		goto done;
> 
> 	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
> 		goto fail;
> 	p[-1] = '\0';
> 	res = try_name(s, part);
> done:
> 	sys_umount("/sys", 0);
> out:
> 	sys_rmdir("/sys");
> 	return res;
> fail:
> 	res = (dev_t) 0;
> 	goto done;
> }
> 
> 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 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;
> }
> 
> __setup("rootflags=", root_data_setup);
> __setup("rootfstype=", fs_names_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)
> {
> 	int err = sys_mount(name, "/root", fs, flags, data);
> 	if (err)
> 		return err;
> 
> 	sys_chdir("/root");
> 	ROOT_DEV = current->fs->pwdmnt->mnt_sb->s_dev;
> 	printk("VFS: Mounted root (%s filesystem)%s.\n",
> 	       current->fs->pwdmnt->mnt_sb->s_type->name,
> 	       current->fs->pwdmnt->mnt_sb->s_flags & MS_RDONLY ? 
> 	       " readonly" : "");
> 	return 0;
> }
> 
> void __init mount_block_root(char *name, int flags)
> {
> 	char *fs_names = __getname();
> 	char *p;
> 	char b[BDEVNAME_SIZE];
> 
> 	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:
> 				flags |= MS_RDONLY;
> 				goto retry;
> 			case -EINVAL:
> 				continue;
> 		}
> 	        /*
> 		 * Allow the user to distinguish between failed open
> 		 * and bad superblock on root device.
> 		 */
> 		__bdevname(ROOT_DEV, b);
> 		printk("VFS: Cannot open root device \"%s\" or %s\n",
> 				root_device_name, b);
> 		printk("Please append a correct \"root=\" boot option\n");
> 		panic("VFS: Unable to mount root fs on %s", b);
> 	}
> 	panic("VFS: Unable to mount root fs on %s", __bdevname(ROOT_DEV, b));
> out:
> 	putname(fs_names);
> }
>  
> #ifdef CONFIG_ROOT_NFS
> static int __init mount_nfs_root(void)
> {
> 	void *data = nfs_root_data();
> 
> 	create_dev("/dev/root", ROOT_DEV, NULL);
> 	if (data &&
> 	    do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
> 		return 1;
> 	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 = open("/dev/root", O_RDWR | O_NDELAY, 0);
> 	if (fd >= 0) {
> 		sys_ioctl(fd, FDEJECT, 0);
> 		close(fd);
> 	}
> 	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
> 	fd = open("/dev/console", O_RDWR, 0);
> 	if (fd >= 0) {
> 		sys_ioctl(fd, TCGETS, (long)&termios);
> 		termios.c_lflag &= ~ICANON;
> 		sys_ioctl(fd, TCSETSF, (long)&termios);
> 		read(fd, &c, 1);
> 		termios.c_lflag |= ICANON;
> 		sys_ioctl(fd, TCSETSF, (long)&termios);
> 		close(fd);
> 	}
> }
> #endif
> 
> void __init mount_root(void)
> {
> #ifdef CONFIG_ROOT_NFS
> 	if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
> 		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
> 	create_dev("/dev/root", ROOT_DEV, root_device_name);
> 	mount_block_root("/dev/root", root_mountflags);
> }
> 
> /*
>  * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
>  */
> void __init prepare_namespace(void)
> {
> 	int is_floppy;
> 
> 	mount_devfs();
> 
> 	md_run_setup();
> 
> 	if (saved_root_name[0]) {
> 		root_device_name = saved_root_name;
> 		ROOT_DEV = name_to_dev_t(root_device_name);
> 		if (strncmp(root_device_name, "/dev/", 5) == 0)
> 			root_device_name += 5;
> 	}
> 
> 	is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
> 
> 	/* This has to be before mounting root, because even readonly mount of reiserfs would replay
> 	   log corrupting stuff */
> 	software_resume();
> 
> 	if (initrd_load())
> 		goto out;
> 
> 	if (is_floppy && rd_doload && rd_load_disk(0))
> 		ROOT_DEV = Root_RAM0;
> 
> 	mount_root();
> out:
> 	umount_devfs("/dev");
> 	sys_mount(".", "/", NULL, MS_MOVE, NULL);
> 	sys_chroot(".");
> 	security_sb_post_mountroot();
> 	mount_devfs_fs ();
> }
> 

VFS: Cannot open root device "304" or hda4

[kernel_286]

[-- Attachment #1: Type: text/plain, Size: 1057 bytes --]


Hi to all, this is my first post on LKML.

I'm trying 2.6.0-test2-mm2 and the compiling process ends with no errors 
except for some warnings about oss modules.
After reboot with the 2.6 I obtain a kernel panic error:

**************************************
VFS: Cannot open root device "304" or hda4
Please append a correct "root=" boot option
VFS: Unable to mount root fs on hda4;
**************************************
I've read old ML posts but the don't help me. 
According to 2.4.21, the root fs is /dev/hda4: I've tried to give "root=0304" 
or "root=/dev/hda4" at the 2.6, but I obtain the same errors.
I've even tried initrd with no changes.

I've introduced some printk in init/do_mount.c (see the linked file at line 
64) and before the kernel panic, the result was :

***************************************
name hda4 - /sys/block/hda4/dev
descriptor -1

name hda - /sys/block/hda/dev
descriptor 0

scanning '3:0'
***************************************

Is it normal?

Thanks a lot.
			Mario

PS: sorry for my 'bad' english.. I'm learning...



[-- Attachment #2: do_mounts.c --]
[-- Type: text/x-csrc, Size: 8587 bytes --]

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

#include "do_mounts.h"

extern int get_filesystem_list(char * buf);

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

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

/* this is initialized in init/main.c */
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);

static dev_t __init try_name(char *name, int part)
{
	char path[64];
	char buf[32];
	int range;
	dev_t res;
	char *s;
	int len;
	int fd;
	unsigned int maj, min;

	/* read device number from .../dev */

	sprintf(path, "/sys/block/%s/dev", name);
	printk("name %s - path %s\n",name, path);
	fd = open(path, 0, 0);
	printk("descriptor %d\n",fd);
	if (fd < 0)
		goto fail;
	len = read(fd, buf, 32);
	close(fd);
	if (len <= 0 || len == 32 || buf[len - 1] != '\n')
		goto fail;
	buf[len - 1] = '\0';
	/*
	 * The format of dev is now %u:%u -- see print_dev_t()
	 */
	printk("scanning `%s'\n", buf);
	if (sscanf(buf, "%u:%u", &maj, &min) == 2)
		res = MKDEV(maj, min);
	else
		goto fail;

	/* if it's there and we are not looking for a partition - that's it */
	if (!part)
		return res;

	/* otherwise read range from .../range */
	sprintf(path, "/sys/block/%s/range", name);
	fd = open(path, 0, 0);
	if (fd < 0)
		goto fail;
	len = read(fd, buf, 32);
	close(fd);
	if (len <= 0 || len == 32 || buf[len - 1] != '\n')
		goto fail;
	buf[len - 1] = '\0';
	range = simple_strtoul(buf, &s, 10);
	if (*s)
		goto fail;

	/* if partition is within range - we got it */
	if (part < range)
		return res + part;
fail:
	return (dev_t) 0;
}

/*
 *	Convert a name into device number.  We accept the following variants:
 *
 *	1) device number in hexadecimal	represents itself
 *	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.
 *
 *	If name doesn't have fall into the categories above, we return 0.
 *	Driverfs is used to check if something is a disk name - it has
 *	all known disks under bus/block/devices.  If the disk name
 *	contains slashes, name of driverfs node has them replaced with
 *	dots.  try_name() does the actual checks, assuming that driverfs
 *	is mounted on rootfs /sys.
 */

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

	sys_mkdir("/sys", 0700);
	if (sys_mount("sysfs", "/sys", "sysfs", 0, NULL) < 0)
		goto out;

	if (strncmp(name, "/dev/", 5) != 0) {
		res = (dev_t) simple_strtoul(name, &p, 16);
		if (*p)
			goto fail;
		goto done;
	}
	name += 5;
	res = Root_NFS;
	if (strcmp(name, "nfs") == 0)
		goto done;

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

	while (p > s && isdigit(p[-1]))
		p--;
	if (p == s || !*p || *p == '0')
		goto fail;
	part = simple_strtoul(p, NULL, 10);
	*p = '\0';
	res = try_name(s, part);
	if (res)
		goto done;

	if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
		goto fail;
	p[-1] = '\0';
	res = try_name(s, part);
done:
	sys_umount("/sys", 0);
out:
	sys_rmdir("/sys");
	return res;
fail:
	res = (dev_t) 0;
	goto done;
}

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 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;
}

__setup("rootflags=", root_data_setup);
__setup("rootfstype=", fs_names_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)
{
	int err = sys_mount(name, "/root", fs, flags, data);
	if (err)
		return err;

	sys_chdir("/root");
	ROOT_DEV = current->fs->pwdmnt->mnt_sb->s_dev;
	printk("VFS: Mounted root (%s filesystem)%s.\n",
	       current->fs->pwdmnt->mnt_sb->s_type->name,
	       current->fs->pwdmnt->mnt_sb->s_flags & MS_RDONLY ? 
	       " readonly" : "");
	return 0;
}

void __init mount_block_root(char *name, int flags)
{
	char *fs_names = __getname();
	char *p;
	char b[BDEVNAME_SIZE];

	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:
				flags |= MS_RDONLY;
				goto retry;
			case -EINVAL:
				continue;
		}
	        /*
		 * Allow the user to distinguish between failed open
		 * and bad superblock on root device.
		 */
		__bdevname(ROOT_DEV, b);
		printk("VFS: Cannot open root device \"%s\" or %s\n",
				root_device_name, b);
		printk("Please append a correct \"root=\" boot option\n");
		panic("VFS: Unable to mount root fs on %s", b);
	}
	panic("VFS: Unable to mount root fs on %s", __bdevname(ROOT_DEV, b));
out:
	putname(fs_names);
}
 
#ifdef CONFIG_ROOT_NFS
static int __init mount_nfs_root(void)
{
	void *data = nfs_root_data();

	create_dev("/dev/root", ROOT_DEV, NULL);
	if (data &&
	    do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
		return 1;
	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 = open("/dev/root", O_RDWR | O_NDELAY, 0);
	if (fd >= 0) {
		sys_ioctl(fd, FDEJECT, 0);
		close(fd);
	}
	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
	fd = open("/dev/console", O_RDWR, 0);
	if (fd >= 0) {
		sys_ioctl(fd, TCGETS, (long)&termios);
		termios.c_lflag &= ~ICANON;
		sys_ioctl(fd, TCSETSF, (long)&termios);
		read(fd, &c, 1);
		termios.c_lflag |= ICANON;
		sys_ioctl(fd, TCSETSF, (long)&termios);
		close(fd);
	}
}
#endif

void __init mount_root(void)
{
#ifdef CONFIG_ROOT_NFS
	if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
		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
	create_dev("/dev/root", ROOT_DEV, root_device_name);
	mount_block_root("/dev/root", root_mountflags);
}

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

	mount_devfs();

	md_run_setup();

	if (saved_root_name[0]) {
		root_device_name = saved_root_name;
		ROOT_DEV = name_to_dev_t(root_device_name);
		if (strncmp(root_device_name, "/dev/", 5) == 0)
			root_device_name += 5;
	}

	is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;

	/* This has to be before mounting root, because even readonly mount of reiserfs would replay
	   log corrupting stuff */
	software_resume();

	if (initrd_load())
		goto out;

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

	mount_root();
out:
	umount_devfs("/dev");
	sys_mount(".", "/", NULL, MS_MOVE, NULL);
	sys_chroot(".");
	security_sb_post_mountroot();
	mount_devfs_fs ();
}