bca1033b09
In the past, I used the root=... command line parameter to specify the root filesystem to the kernel. Now it seems that specifying it is not necessary. The kernel detects the root filesystem even if the kernel command line is empty. My root fs is on a raid1 device by the way, and I am not using initrd for the boot process. If the kernel detects the root filesystem somehow, I think it should print out the result of this detection, otherwise I will not know which device has the root filesystem. Or is there an easy way to get this information on a running system? I had a quick look at the /proc and /sys filesystems, but haven't found anything useful there. Signed-off-by: Marton Balint <cus@fazekas.hu> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
412 lines
9 KiB
C
412 lines
9 KiB
C
#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/ctype.h>
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#include <linux/fd.h>
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#include <linux/tty.h>
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#include <linux/suspend.h>
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#include <linux/root_dev.h>
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#include <linux/security.h>
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#include <linux/delay.h>
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#include <linux/genhd.h>
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#include <linux/mount.h>
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/initrd.h>
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#include <linux/nfs_fs.h>
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#include <linux/nfs_fs_sb.h>
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#include <linux/nfs_mount.h>
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#include "do_mounts.h"
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int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
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int root_mountflags = MS_RDONLY | MS_SILENT;
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static char * __initdata root_device_name;
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static char __initdata saved_root_name[64];
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static int __initdata root_wait;
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dev_t ROOT_DEV;
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static int __init load_ramdisk(char *str)
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{
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rd_doload = simple_strtol(str,NULL,0) & 3;
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return 1;
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}
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__setup("load_ramdisk=", load_ramdisk);
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static int __init readonly(char *str)
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{
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if (*str)
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return 0;
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root_mountflags |= MS_RDONLY;
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return 1;
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}
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static int __init readwrite(char *str)
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{
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if (*str)
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return 0;
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root_mountflags &= ~MS_RDONLY;
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return 1;
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}
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__setup("ro", readonly);
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__setup("rw", readwrite);
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/*
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* Convert a name into device number. We accept the following variants:
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*
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* 1) device number in hexadecimal represents itself
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* 2) /dev/nfs represents Root_NFS (0xff)
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* 3) /dev/<disk_name> represents the device number of disk
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* 4) /dev/<disk_name><decimal> represents the device number
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* of partition - device number of disk plus the partition number
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* 5) /dev/<disk_name>p<decimal> - same as the above, that form is
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* used when disk name of partitioned disk ends on a digit.
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*
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* If name doesn't have fall into the categories above, we return (0,0).
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* block_class is used to check if something is a disk name. If the disk
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* name contains slashes, the device name has them replaced with
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* bangs.
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*/
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dev_t name_to_dev_t(char *name)
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{
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char s[32];
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char *p;
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dev_t res = 0;
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int part;
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if (strncmp(name, "/dev/", 5) != 0) {
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unsigned maj, min;
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if (sscanf(name, "%u:%u", &maj, &min) == 2) {
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res = MKDEV(maj, min);
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if (maj != MAJOR(res) || min != MINOR(res))
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goto fail;
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} else {
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res = new_decode_dev(simple_strtoul(name, &p, 16));
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if (*p)
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goto fail;
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}
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goto done;
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}
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name += 5;
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res = Root_NFS;
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if (strcmp(name, "nfs") == 0)
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goto done;
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res = Root_RAM0;
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if (strcmp(name, "ram") == 0)
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goto done;
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if (strlen(name) > 31)
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goto fail;
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strcpy(s, name);
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for (p = s; *p; p++)
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if (*p == '/')
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*p = '!';
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res = blk_lookup_devt(s, 0);
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if (res)
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goto done;
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/*
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* try non-existant, but valid partition, which may only exist
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* after revalidating the disk, like partitioned md devices
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*/
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while (p > s && isdigit(p[-1]))
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p--;
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if (p == s || !*p || *p == '0')
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goto fail;
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/* try disk name without <part number> */
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part = simple_strtoul(p, NULL, 10);
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*p = '\0';
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res = blk_lookup_devt(s, part);
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if (res)
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goto done;
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/* try disk name without p<part number> */
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if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
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goto fail;
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p[-1] = '\0';
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res = blk_lookup_devt(s, part);
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if (res)
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goto done;
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fail:
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return 0;
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done:
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return res;
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}
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static int __init root_dev_setup(char *line)
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{
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strlcpy(saved_root_name, line, sizeof(saved_root_name));
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return 1;
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}
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__setup("root=", root_dev_setup);
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static int __init rootwait_setup(char *str)
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{
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if (*str)
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return 0;
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root_wait = 1;
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return 1;
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}
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__setup("rootwait", rootwait_setup);
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static char * __initdata root_mount_data;
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static int __init root_data_setup(char *str)
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{
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root_mount_data = str;
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return 1;
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}
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static char * __initdata root_fs_names;
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static int __init fs_names_setup(char *str)
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{
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root_fs_names = str;
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return 1;
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}
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static unsigned int __initdata root_delay;
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static int __init root_delay_setup(char *str)
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{
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root_delay = simple_strtoul(str, NULL, 0);
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return 1;
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}
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__setup("rootflags=", root_data_setup);
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__setup("rootfstype=", fs_names_setup);
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__setup("rootdelay=", root_delay_setup);
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static void __init get_fs_names(char *page)
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{
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char *s = page;
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if (root_fs_names) {
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strcpy(page, root_fs_names);
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while (*s++) {
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if (s[-1] == ',')
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s[-1] = '\0';
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}
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} else {
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int len = get_filesystem_list(page);
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char *p, *next;
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page[len] = '\0';
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for (p = page-1; p; p = next) {
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next = strchr(++p, '\n');
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if (*p++ != '\t')
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continue;
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while ((*s++ = *p++) != '\n')
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;
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s[-1] = '\0';
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}
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}
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*s = '\0';
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}
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static int __init do_mount_root(char *name, char *fs, int flags, void *data)
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{
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int err = sys_mount(name, "/root", fs, flags, data);
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if (err)
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return err;
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sys_chdir("/root");
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ROOT_DEV = current->fs->pwd.mnt->mnt_sb->s_dev;
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printk("VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
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current->fs->pwd.mnt->mnt_sb->s_type->name,
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current->fs->pwd.mnt->mnt_sb->s_flags & MS_RDONLY ?
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" readonly" : "", MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
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return 0;
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}
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void __init mount_block_root(char *name, int flags)
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{
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char *fs_names = __getname();
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char *p;
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#ifdef CONFIG_BLOCK
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char b[BDEVNAME_SIZE];
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#else
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const char *b = name;
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#endif
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get_fs_names(fs_names);
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retry:
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for (p = fs_names; *p; p += strlen(p)+1) {
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int err = do_mount_root(name, p, flags, root_mount_data);
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switch (err) {
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case 0:
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goto out;
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case -EACCES:
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flags |= MS_RDONLY;
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goto retry;
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case -EINVAL:
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continue;
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}
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/*
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* Allow the user to distinguish between failed sys_open
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* and bad superblock on root device.
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* and give them a list of the available devices
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*/
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#ifdef CONFIG_BLOCK
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__bdevname(ROOT_DEV, b);
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#endif
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printk("VFS: Cannot open root device \"%s\" or %s\n",
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root_device_name, b);
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printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
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printk_all_partitions();
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#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
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printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
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"explicit textual name for \"root=\" boot option.\n");
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#endif
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panic("VFS: Unable to mount root fs on %s", b);
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}
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printk("List of all partitions:\n");
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printk_all_partitions();
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printk("No filesystem could mount root, tried: ");
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for (p = fs_names; *p; p += strlen(p)+1)
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printk(" %s", p);
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printk("\n");
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#ifdef CONFIG_BLOCK
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__bdevname(ROOT_DEV, b);
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#endif
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panic("VFS: Unable to mount root fs on %s", b);
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out:
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putname(fs_names);
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}
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#ifdef CONFIG_ROOT_NFS
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static int __init mount_nfs_root(void)
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{
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void *data = nfs_root_data();
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create_dev("/dev/root", ROOT_DEV);
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if (data &&
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do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0)
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return 1;
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return 0;
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}
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#endif
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#if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
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void __init change_floppy(char *fmt, ...)
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{
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struct termios termios;
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char buf[80];
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char c;
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int fd;
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va_list args;
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va_start(args, fmt);
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vsprintf(buf, fmt, args);
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va_end(args);
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fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
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if (fd >= 0) {
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sys_ioctl(fd, FDEJECT, 0);
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sys_close(fd);
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}
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printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
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fd = sys_open("/dev/console", O_RDWR, 0);
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if (fd >= 0) {
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sys_ioctl(fd, TCGETS, (long)&termios);
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termios.c_lflag &= ~ICANON;
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sys_ioctl(fd, TCSETSF, (long)&termios);
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sys_read(fd, &c, 1);
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termios.c_lflag |= ICANON;
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sys_ioctl(fd, TCSETSF, (long)&termios);
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sys_close(fd);
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}
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}
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#endif
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void __init mount_root(void)
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{
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#ifdef CONFIG_ROOT_NFS
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if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) {
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if (mount_nfs_root())
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return;
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printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
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ROOT_DEV = Root_FD0;
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}
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#endif
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#ifdef CONFIG_BLK_DEV_FD
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if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
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/* rd_doload is 2 for a dual initrd/ramload setup */
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if (rd_doload==2) {
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if (rd_load_disk(1)) {
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ROOT_DEV = Root_RAM1;
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root_device_name = NULL;
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}
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} else
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change_floppy("root floppy");
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}
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#endif
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#ifdef CONFIG_BLOCK
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create_dev("/dev/root", ROOT_DEV);
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mount_block_root("/dev/root", root_mountflags);
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#endif
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}
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/*
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* Prepare the namespace - decide what/where to mount, load ramdisks, etc.
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*/
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void __init prepare_namespace(void)
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{
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int is_floppy;
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if (root_delay) {
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printk(KERN_INFO "Waiting %dsec before mounting root device...\n",
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root_delay);
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ssleep(root_delay);
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}
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/* wait for the known devices to complete their probing */
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while (driver_probe_done() != 0)
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msleep(100);
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md_run_setup();
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if (saved_root_name[0]) {
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root_device_name = saved_root_name;
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if (!strncmp(root_device_name, "mtd", 3) ||
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!strncmp(root_device_name, "ubi", 3)) {
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mount_block_root(root_device_name, root_mountflags);
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goto out;
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}
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ROOT_DEV = name_to_dev_t(root_device_name);
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if (strncmp(root_device_name, "/dev/", 5) == 0)
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root_device_name += 5;
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}
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if (initrd_load())
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goto out;
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/* wait for any asynchronous scanning to complete */
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if ((ROOT_DEV == 0) && root_wait) {
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printk(KERN_INFO "Waiting for root device %s...\n",
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saved_root_name);
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while (driver_probe_done() != 0 ||
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(ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
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msleep(100);
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}
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is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
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if (is_floppy && rd_doload && rd_load_disk(0))
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ROOT_DEV = Root_RAM0;
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mount_root();
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out:
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sys_mount(".", "/", NULL, MS_MOVE, NULL);
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sys_chroot(".");
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}
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