1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
3 #include <linux/sched.h>
4 #include <linux/ctype.h>
7 #include <linux/suspend.h>
8 #include <linux/root_dev.h>
9 #include <linux/security.h>
10 #include <linux/delay.h>
11 #include <linux/mount.h>
12 #include <linux/device.h>
13 #include <linux/init.h>
15 #include <linux/initrd.h>
16 #include <linux/async.h>
17 #include <linux/fs_struct.h>
18 #include <linux/slab.h>
19 #include <linux/ramfs.h>
20 #include <linux/shmem_fs.h>
21 #include <linux/ktime.h>
23 #include <linux/nfs_fs.h>
24 #include <linux/nfs_fs_sb.h>
25 #include <linux/nfs_mount.h>
26 #include <linux/raid/detect.h>
27 #include <uapi/linux/mount.h>
29 #include "do_mounts.h"
31 int root_mountflags
= MS_RDONLY
| MS_SILENT
;
32 static char __initdata saved_root_name
[64];
37 static int __init
load_ramdisk(char *str
)
39 pr_warn("ignoring the deprecated load_ramdisk= option\n");
42 __setup("load_ramdisk=", load_ramdisk
);
44 static int __init
readonly(char *str
)
48 root_mountflags
|= MS_RDONLY
;
52 static int __init
readwrite(char *str
)
56 root_mountflags
&= ~MS_RDONLY
;
60 __setup("ro", readonly
);
61 __setup("rw", readwrite
);
63 static int __init
root_dev_setup(char *line
)
65 strscpy(saved_root_name
, line
, sizeof(saved_root_name
));
69 __setup("root=", root_dev_setup
);
71 static int __init
rootwait_setup(char *str
)
79 __setup("rootwait", rootwait_setup
);
81 static int __init
rootwait_timeout_setup(char *str
)
85 if (kstrtoint(str
, 0, &sec
) || sec
< 0) {
86 pr_warn("ignoring invalid rootwait value\n");
90 if (check_mul_overflow(sec
, MSEC_PER_SEC
, &root_wait
)) {
91 pr_warn("ignoring excessive rootwait value\n");
98 /* Fallback to indefinite wait */
104 __setup("rootwait=", rootwait_timeout_setup
);
106 static char * __initdata root_mount_data
;
107 static int __init
root_data_setup(char *str
)
109 root_mount_data
= str
;
113 static char * __initdata root_fs_names
;
114 static int __init
fs_names_setup(char *str
)
120 static unsigned int __initdata root_delay
;
121 static int __init
root_delay_setup(char *str
)
123 root_delay
= simple_strtoul(str
, NULL
, 0);
127 __setup("rootflags=", root_data_setup
);
128 __setup("rootfstype=", fs_names_setup
);
129 __setup("rootdelay=", root_delay_setup
);
131 /* This can return zero length strings. Caller should check */
132 static int __init
split_fs_names(char *page
, size_t size
)
137 strscpy(p
, root_fs_names
, size
);
148 static int __init
do_mount_root(const char *name
, const char *fs
,
149 const int flags
, const void *data
)
151 struct super_block
*s
;
152 struct page
*p
= NULL
;
153 char *data_page
= NULL
;
157 /* init_mount() requires a full page as fifth argument */
158 p
= alloc_page(GFP_KERNEL
);
161 data_page
= page_address(p
);
162 /* zero-pad. init_mount() will make sure it's terminated */
163 strncpy(data_page
, data
, PAGE_SIZE
);
166 ret
= init_mount(name
, "/root", fs
, flags
, data_page
);
171 s
= current
->fs
->pwd
.dentry
->d_sb
;
174 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
176 sb_rdonly(s
) ? " readonly" : "",
177 MAJOR(ROOT_DEV
), MINOR(ROOT_DEV
));
185 void __init
mount_root_generic(char *name
, char *pretty_name
, int flags
)
187 struct page
*page
= alloc_page(GFP_KERNEL
);
188 char *fs_names
= page_address(page
);
190 char b
[BDEVNAME_SIZE
];
193 scnprintf(b
, BDEVNAME_SIZE
, "unknown-block(%u,%u)",
194 MAJOR(ROOT_DEV
), MINOR(ROOT_DEV
));
196 num_fs
= split_fs_names(fs_names
, PAGE_SIZE
);
198 num_fs
= list_bdev_fs_names(fs_names
, PAGE_SIZE
);
200 for (i
= 0, p
= fs_names
; i
< num_fs
; i
++, p
+= strlen(p
)+1) {
205 err
= do_mount_root(name
, p
, flags
, root_mount_data
);
214 * Allow the user to distinguish between failed sys_open
215 * and bad superblock on root device.
216 * and give them a list of the available devices
218 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
219 pretty_name
, b
, err
);
220 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
221 printk_all_partitions();
224 num_fs
= list_bdev_fs_names(fs_names
, PAGE_SIZE
);
226 pr_err("Can't find any bdev filesystem to be used for mount!\n");
228 pr_err("List of all bdev filesystems:\n");
229 for (i
= 0, p
= fs_names
; i
< num_fs
; i
++, p
+= strlen(p
)+1)
234 panic("VFS: Unable to mount root fs on %s", b
);
236 if (!(flags
& SB_RDONLY
)) {
241 printk("List of all partitions:\n");
242 printk_all_partitions();
243 printk("No filesystem could mount root, tried: ");
244 for (i
= 0, p
= fs_names
; i
< num_fs
; i
++, p
+= strlen(p
)+1)
247 panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name
, b
);
252 #ifdef CONFIG_ROOT_NFS
254 #define NFSROOT_TIMEOUT_MIN 5
255 #define NFSROOT_TIMEOUT_MAX 30
256 #define NFSROOT_RETRY_MAX 5
258 static void __init
mount_nfs_root(void)
260 char *root_dev
, *root_data
;
261 unsigned int timeout
;
264 if (nfs_root_data(&root_dev
, &root_data
))
268 * The server or network may not be ready, so try several
269 * times. Stop after a few tries in case the client wants
270 * to fall back to other boot methods.
272 timeout
= NFSROOT_TIMEOUT_MIN
;
273 for (try = 1; ; try++) {
274 if (!do_mount_root(root_dev
, "nfs", root_mountflags
, root_data
))
276 if (try > NFSROOT_RETRY_MAX
)
279 /* Wait, in case the server refused us immediately */
282 if (timeout
> NFSROOT_TIMEOUT_MAX
)
283 timeout
= NFSROOT_TIMEOUT_MAX
;
286 pr_err("VFS: Unable to mount root fs via NFS.\n");
289 static inline void mount_nfs_root(void)
292 #endif /* CONFIG_ROOT_NFS */
294 #ifdef CONFIG_CIFS_ROOT
296 #define CIFSROOT_TIMEOUT_MIN 5
297 #define CIFSROOT_TIMEOUT_MAX 30
298 #define CIFSROOT_RETRY_MAX 5
300 static void __init
mount_cifs_root(void)
302 char *root_dev
, *root_data
;
303 unsigned int timeout
;
306 if (cifs_root_data(&root_dev
, &root_data
))
309 timeout
= CIFSROOT_TIMEOUT_MIN
;
310 for (try = 1; ; try++) {
311 if (!do_mount_root(root_dev
, "cifs", root_mountflags
,
314 if (try > CIFSROOT_RETRY_MAX
)
319 if (timeout
> CIFSROOT_TIMEOUT_MAX
)
320 timeout
= CIFSROOT_TIMEOUT_MAX
;
323 pr_err("VFS: Unable to mount root fs via SMB.\n");
326 static inline void mount_cifs_root(void)
329 #endif /* CONFIG_CIFS_ROOT */
331 static bool __init
fs_is_nodev(char *fstype
)
333 struct file_system_type
*fs
= get_fs_type(fstype
);
337 ret
= !(fs
->fs_flags
& FS_REQUIRES_DEV
);
344 static int __init
mount_nodev_root(char *root_device_name
)
346 char *fs_names
, *fstype
;
350 fs_names
= (void *)__get_free_page(GFP_KERNEL
);
353 num_fs
= split_fs_names(fs_names
, PAGE_SIZE
);
355 for (i
= 0, fstype
= fs_names
; i
< num_fs
;
356 i
++, fstype
+= strlen(fstype
) + 1) {
359 if (!fs_is_nodev(fstype
))
361 err
= do_mount_root(root_device_name
, fstype
, root_mountflags
,
367 free_page((unsigned long)fs_names
);
372 static void __init
mount_block_root(char *root_device_name
)
374 int err
= create_dev("/dev/root", ROOT_DEV
);
377 pr_emerg("Failed to create /dev/root: %d\n", err
);
378 mount_root_generic("/dev/root", root_device_name
, root_mountflags
);
381 static inline void mount_block_root(char *root_device_name
)
384 #endif /* CONFIG_BLOCK */
386 void __init
mount_root(char *root_device_name
)
396 mount_root_generic(root_device_name
, root_device_name
,
400 if (root_device_name
&& root_fs_names
&&
401 mount_nodev_root(root_device_name
) == 0)
405 mount_block_root(root_device_name
);
410 /* wait for any asynchronous scanning to complete */
411 static void __init
wait_for_root(char *root_device_name
)
418 pr_info("Waiting for root device %s...\n", root_device_name
);
420 end
= ktime_add_ms(ktime_get_raw(), root_wait
);
422 while (!driver_probe_done() ||
423 early_lookup_bdev(root_device_name
, &ROOT_DEV
) < 0) {
425 if (root_wait
> 0 && ktime_after(ktime_get_raw(), end
))
429 async_synchronize_full();
433 static dev_t __init
parse_root_device(char *root_device_name
)
438 if (!strncmp(root_device_name
, "mtd", 3) ||
439 !strncmp(root_device_name
, "ubi", 3))
441 if (strcmp(root_device_name
, "/dev/nfs") == 0)
443 if (strcmp(root_device_name
, "/dev/cifs") == 0)
445 if (strcmp(root_device_name
, "/dev/ram") == 0)
448 error
= early_lookup_bdev(root_device_name
, &dev
);
450 if (error
== -EINVAL
&& root_wait
) {
451 pr_err("Disabling rootwait; root= is invalid.\n");
460 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
462 void __init
prepare_namespace(void)
465 printk(KERN_INFO
"Waiting %d sec before mounting root device...\n",
471 * wait for the known devices to complete their probing
473 * Note: this is a potential source of long boot delays.
474 * For example, it is not atypical to wait 5 seconds here
475 * for the touchpad of a laptop to initialize.
477 wait_for_device_probe();
481 if (saved_root_name
[0])
482 ROOT_DEV
= parse_root_device(saved_root_name
);
484 if (initrd_load(saved_root_name
))
488 wait_for_root(saved_root_name
);
489 mount_root(saved_root_name
);
492 init_mount(".", "/", NULL
, MS_MOVE
, NULL
);
496 static bool is_tmpfs
;
497 static int rootfs_init_fs_context(struct fs_context
*fc
)
499 if (IS_ENABLED(CONFIG_TMPFS
) && is_tmpfs
)
500 return shmem_init_fs_context(fc
);
502 return ramfs_init_fs_context(fc
);
505 struct file_system_type rootfs_fs_type
= {
507 .init_fs_context
= rootfs_init_fs_context
,
508 .kill_sb
= kill_litter_super
,
511 void __init
init_rootfs(void)
513 if (IS_ENABLED(CONFIG_TMPFS
) && !saved_root_name
[0] &&
514 (!root_fs_names
|| strstr(root_fs_names
, "tmpfs")))