diff options
Diffstat (limited to 'init/do_mounts.c')
| -rw-r--r-- | init/do_mounts.c | 519 |
1 files changed, 519 insertions, 0 deletions
diff --git a/init/do_mounts.c b/init/do_mounts.c new file mode 100644 index 0000000000..21d065a55a --- /dev/null +++ b/init/do_mounts.c @@ -0,0 +1,519 @@ +// 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)) { + if (!saved_root_name[0] && !root_fs_names) + is_tmpfs = true; + else if (root_fs_names && !!strstr(root_fs_names, "tmpfs")) + is_tmpfs = true; + } +} |