483 lines
10 KiB
C
483 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#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/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/async.h>
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#include <linux/fs_struct.h>
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#include <linux/slab.h>
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#include <linux/ramfs.h>
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#include <linux/shmem_fs.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 <linux/raid/detect.h>
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#include <uapi/linux/mount.h>
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#include "do_mounts.h"
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int root_mountflags = MS_RDONLY | MS_SILENT;
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static char __initdata saved_root_name[64];
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static int 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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pr_warn("ignoring the deprecated load_ramdisk= option\n");
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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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static int __init root_dev_setup(char *line)
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{
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strscpy(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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/* This can return zero length strings. Caller should check */
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static int __init split_fs_names(char *page, size_t size)
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{
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int count = 1;
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char *p = page;
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strscpy(p, root_fs_names, size);
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while (*p++) {
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if (p[-1] == ',') {
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p[-1] = '\0';
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count++;
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}
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}
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return count;
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}
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static int __init do_mount_root(const char *name, const char *fs,
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const int flags, const void *data)
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{
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struct super_block *s;
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struct page *p = NULL;
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char *data_page = NULL;
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int ret;
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if (data) {
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/* init_mount() requires a full page as fifth argument */
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p = alloc_page(GFP_KERNEL);
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if (!p)
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return -ENOMEM;
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data_page = page_address(p);
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/* zero-pad. init_mount() will make sure it's terminated */
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strncpy(data_page, data, PAGE_SIZE);
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}
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ret = init_mount(name, "/root", fs, flags, data_page);
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if (ret)
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goto out;
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init_chdir("/root");
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s = current->fs->pwd.dentry->d_sb;
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ROOT_DEV = s->s_dev;
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printk(KERN_INFO
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"VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
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s->s_type->name,
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sb_rdonly(s) ? " readonly" : "",
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MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
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out:
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if (p)
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put_page(p);
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return ret;
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}
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void __init mount_root_generic(char *name, char *pretty_name, int flags)
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{
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struct page *page = alloc_page(GFP_KERNEL);
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char *fs_names = page_address(page);
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char *p;
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char b[BDEVNAME_SIZE];
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int num_fs, i;
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scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
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MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
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if (root_fs_names)
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num_fs = split_fs_names(fs_names, PAGE_SIZE);
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else
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num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
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retry:
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for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
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int err;
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if (!*p)
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continue;
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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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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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printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
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pretty_name, b, err);
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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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if (root_fs_names)
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num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
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if (!num_fs)
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pr_err("Can't find any bdev filesystem to be used for mount!\n");
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else {
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pr_err("List of all bdev filesystems:\n");
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for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
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pr_err(" %s", p);
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pr_err("\n");
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}
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panic("VFS: Unable to mount root fs on %s", b);
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}
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if (!(flags & SB_RDONLY)) {
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flags |= SB_RDONLY;
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goto retry;
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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 (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
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printk(" %s", p);
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printk("\n");
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panic("VFS: Unable to mount root fs on %s", b);
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out:
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put_page(page);
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}
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#ifdef CONFIG_ROOT_NFS
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#define NFSROOT_TIMEOUT_MIN 5
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#define NFSROOT_TIMEOUT_MAX 30
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#define NFSROOT_RETRY_MAX 5
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static void __init mount_nfs_root(void)
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{
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char *root_dev, *root_data;
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unsigned int timeout;
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int try;
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if (nfs_root_data(&root_dev, &root_data))
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goto fail;
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/*
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* The server or network may not be ready, so try several
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* times. Stop after a few tries in case the client wants
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* to fall back to other boot methods.
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*/
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timeout = NFSROOT_TIMEOUT_MIN;
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for (try = 1; ; try++) {
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if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))
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return;
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if (try > NFSROOT_RETRY_MAX)
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break;
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/* Wait, in case the server refused us immediately */
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ssleep(timeout);
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timeout <<= 1;
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if (timeout > NFSROOT_TIMEOUT_MAX)
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timeout = NFSROOT_TIMEOUT_MAX;
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}
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fail:
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pr_err("VFS: Unable to mount root fs via NFS.\n");
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}
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#else
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static inline void mount_nfs_root(void)
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{
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}
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#endif /* CONFIG_ROOT_NFS */
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#ifdef CONFIG_CIFS_ROOT
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#define CIFSROOT_TIMEOUT_MIN 5
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#define CIFSROOT_TIMEOUT_MAX 30
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#define CIFSROOT_RETRY_MAX 5
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static void __init mount_cifs_root(void)
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{
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char *root_dev, *root_data;
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unsigned int timeout;
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int try;
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if (cifs_root_data(&root_dev, &root_data))
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goto fail;
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timeout = CIFSROOT_TIMEOUT_MIN;
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for (try = 1; ; try++) {
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if (!do_mount_root(root_dev, "cifs", root_mountflags,
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root_data))
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return;
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if (try > CIFSROOT_RETRY_MAX)
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break;
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ssleep(timeout);
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timeout <<= 1;
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if (timeout > CIFSROOT_TIMEOUT_MAX)
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timeout = CIFSROOT_TIMEOUT_MAX;
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}
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fail:
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pr_err("VFS: Unable to mount root fs via SMB.\n");
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}
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#else
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static inline void mount_cifs_root(void)
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{
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}
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#endif /* CONFIG_CIFS_ROOT */
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static bool __init fs_is_nodev(char *fstype)
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{
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struct file_system_type *fs = get_fs_type(fstype);
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bool ret = false;
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if (fs) {
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ret = !(fs->fs_flags & FS_REQUIRES_DEV);
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put_filesystem(fs);
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}
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return ret;
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}
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static int __init mount_nodev_root(char *root_device_name)
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{
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char *fs_names, *fstype;
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int err = -EINVAL;
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int num_fs, i;
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fs_names = (void *)__get_free_page(GFP_KERNEL);
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if (!fs_names)
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return -EINVAL;
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num_fs = split_fs_names(fs_names, PAGE_SIZE);
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for (i = 0, fstype = fs_names; i < num_fs;
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i++, fstype += strlen(fstype) + 1) {
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if (!*fstype)
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continue;
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if (!fs_is_nodev(fstype))
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continue;
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err = do_mount_root(root_device_name, fstype, root_mountflags,
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root_mount_data);
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if (!err)
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break;
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}
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free_page((unsigned long)fs_names);
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return err;
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}
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#ifdef CONFIG_BLOCK
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static void __init mount_block_root(char *root_device_name)
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{
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int err = create_dev("/dev/root", ROOT_DEV);
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if (err < 0)
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pr_emerg("Failed to create /dev/root: %d\n", err);
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mount_root_generic("/dev/root", root_device_name, root_mountflags);
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}
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#else
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static inline void mount_block_root(char *root_device_name)
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{
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}
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#endif /* CONFIG_BLOCK */
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void __init mount_root(char *root_device_name)
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{
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switch (ROOT_DEV) {
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case Root_NFS:
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mount_nfs_root();
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break;
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case Root_CIFS:
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mount_cifs_root();
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break;
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case Root_Generic:
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mount_root_generic(root_device_name, root_device_name,
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root_mountflags);
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break;
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case 0:
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if (root_device_name && root_fs_names &&
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mount_nodev_root(root_device_name) == 0)
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break;
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fallthrough;
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default:
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mount_block_root(root_device_name);
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break;
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}
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}
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/* wait for any asynchronous scanning to complete */
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static void __init wait_for_root(char *root_device_name)
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{
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if (ROOT_DEV != 0)
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return;
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pr_info("Waiting for root device %s...\n", root_device_name);
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while (!driver_probe_done() ||
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early_lookup_bdev(root_device_name, &ROOT_DEV) < 0)
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msleep(5);
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async_synchronize_full();
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}
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static dev_t __init parse_root_device(char *root_device_name)
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{
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int error;
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dev_t dev;
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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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return Root_Generic;
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if (strcmp(root_device_name, "/dev/nfs") == 0)
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return Root_NFS;
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if (strcmp(root_device_name, "/dev/cifs") == 0)
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return Root_CIFS;
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if (strcmp(root_device_name, "/dev/ram") == 0)
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return Root_RAM0;
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error = early_lookup_bdev(root_device_name, &dev);
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if (error) {
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if (error == -EINVAL && root_wait) {
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pr_err("Disabling rootwait; root= is invalid.\n");
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root_wait = 0;
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}
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return 0;
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}
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return dev;
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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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if (root_delay) {
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printk(KERN_INFO "Waiting %d sec 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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/*
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* wait for the known devices to complete their probing
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*
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* Note: this is a potential source of long boot delays.
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* For example, it is not atypical to wait 5 seconds here
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* for the touchpad of a laptop to initialize.
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*/
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wait_for_device_probe();
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md_run_setup();
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if (saved_root_name[0])
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ROOT_DEV = parse_root_device(saved_root_name);
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if (initrd_load(saved_root_name))
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goto out;
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if (root_wait)
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wait_for_root(saved_root_name);
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mount_root(saved_root_name);
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out:
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devtmpfs_mount();
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init_mount(".", "/", NULL, MS_MOVE, NULL);
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init_chroot(".");
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}
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static bool is_tmpfs;
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static int rootfs_init_fs_context(struct fs_context *fc)
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{
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if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
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return shmem_init_fs_context(fc);
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return ramfs_init_fs_context(fc);
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}
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struct file_system_type rootfs_fs_type = {
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.name = "rootfs",
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.init_fs_context = rootfs_init_fs_context,
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.kill_sb = kill_litter_super,
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};
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void __init init_rootfs(void)
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{
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if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
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(!root_fs_names || strstr(root_fs_names, "tmpfs")))
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is_tmpfs = true;
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}
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