// 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", 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) && !saved_root_name[0] && (!root_fs_names || strstr(root_fs_names, "tmpfs"))) is_tmpfs = true; }