2 * Many of the syscalls used in this file expect some of the arguments
3 * to be __user pointers not __kernel pointers. To limit the sparse
4 * noise, turn off sparse checking for this file.
8 #warning "Sparse checking disabled for this file"
11 #include <linux/module.h>
12 #include <linux/sched.h>
13 #include <linux/ctype.h>
15 #include <linux/tty.h>
16 #include <linux/suspend.h>
17 #include <linux/root_dev.h>
18 #include <linux/security.h>
19 #include <linux/delay.h>
20 #include <linux/genhd.h>
21 #include <linux/mount.h>
22 #include <linux/device.h>
23 #include <linux/init.h>
25 #include <linux/initrd.h>
26 #include <linux/async.h>
27 #include <linux/fs_struct.h>
28 #include <linux/slab.h>
29 #include <linux/ramfs.h>
30 #include <linux/shmem_fs.h>
32 #include <linux/nfs_fs.h>
33 #include <linux/nfs_fs_sb.h>
34 #include <linux/nfs_mount.h>
36 #include "do_mounts.h"
38 int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */
40 int root_mountflags = MS_RDONLY | MS_SILENT;
41 static char * __initdata root_device_name;
42 static char __initdata saved_root_name[64];
47 static int __init load_ramdisk(char *str)
49 rd_doload = simple_strtol(str,NULL,0) & 3;
52 __setup("load_ramdisk=", load_ramdisk);
54 static int __init readonly(char *str)
58 root_mountflags |= MS_RDONLY;
62 static int __init readwrite(char *str)
66 root_mountflags &= ~MS_RDONLY;
70 __setup("ro", readonly);
71 __setup("rw", readwrite);
80 * match_dev_by_uuid - callback for finding a partition using its uuid
81 * @dev: device passed in by the caller
82 * @data: opaque pointer to the desired struct uuidcmp to match
84 * Returns 1 if the device matches, and 0 otherwise.
86 static int match_dev_by_uuid(struct device *dev, const void *data)
88 const struct uuidcmp *cmp = data;
89 struct hd_struct *part = dev_to_part(dev);
94 if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
104 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
105 * @uuid_str: char array containing ascii UUID
107 * The function will return the first partition which contains a matching
108 * UUID value in its partition_meta_info struct. This does not search
109 * by filesystem UUIDs.
111 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
112 * extracted and used as an offset from the partition identified by the UUID.
114 * Returns the matching dev_t on success or 0 on failure.
116 static dev_t devt_from_partuuid(const char *uuid_str)
120 struct device *dev = NULL;
121 struct gendisk *disk;
122 struct hd_struct *part;
124 bool clear_root_wait = false;
129 slash = strchr(uuid_str, '/');
130 /* Check for optional partition number offset attributes. */
133 /* Explicitly fail on poor PARTUUID syntax. */
134 if (sscanf(slash + 1,
135 "PARTNROFF=%d%c", &offset, &c) != 1) {
136 clear_root_wait = true;
139 cmp.len = slash - uuid_str;
141 cmp.len = strlen(uuid_str);
145 clear_root_wait = true;
149 dev = class_find_device(&block_class, NULL, &cmp,
156 /* Attempt to find the partition by offset. */
161 disk = part_to_disk(dev_to_part(dev));
162 part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
164 res = part_devt(part);
165 put_device(part_to_dev(part));
171 if (clear_root_wait) {
172 pr_err("VFS: PARTUUID= is invalid.\n"
173 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
175 pr_err("Disabling rootwait; root= is invalid.\n");
183 * Convert a name into device number. We accept the following variants:
185 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself
186 * no leading 0x, for example b302.
187 * 2) /dev/nfs represents Root_NFS (0xff)
188 * 3) /dev/<disk_name> represents the device number of disk
189 * 4) /dev/<disk_name><decimal> represents the device number
190 * of partition - device number of disk plus the partition number
191 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
192 * used when disk name of partitioned disk ends on a digit.
193 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
194 * unique id of a partition if the partition table provides it.
195 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
196 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
197 * filled hex representation of the 32-bit "NT disk signature", and PP
198 * is a zero-filled hex representation of the 1-based partition number.
199 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
200 * a partition with a known unique id.
201 * 8) <major>:<minor> major and minor number of the device separated by
204 * If name doesn't have fall into the categories above, we return (0,0).
205 * block_class is used to check if something is a disk name. If the disk
206 * name contains slashes, the device name has them replaced with
210 dev_t name_to_dev_t(const char *name)
218 if (strncmp(name, "PARTUUID=", 9) == 0) {
220 res = devt_from_partuuid(name);
227 if (strncmp(name, "/dev/", 5) != 0) {
228 unsigned maj, min, offset;
231 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
232 (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
233 res = MKDEV(maj, min);
234 if (maj != MAJOR(res) || min != MINOR(res))
237 res = new_decode_dev(simple_strtoul(name, &p, 16));
246 if (strcmp(name, "nfs") == 0)
249 if (strcmp(name, "ram") == 0)
252 if (strlen(name) > 31)
258 res = blk_lookup_devt(s, 0);
263 * try non-existent, but valid partition, which may only exist
264 * after revalidating the disk, like partitioned md devices
266 while (p > s && isdigit(p[-1]))
268 if (p == s || !*p || *p == '0')
271 /* try disk name without <part number> */
272 part = simple_strtoul(p, NULL, 10);
274 res = blk_lookup_devt(s, part);
278 /* try disk name without p<part number> */
279 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
282 res = blk_lookup_devt(s, part);
291 EXPORT_SYMBOL_GPL(name_to_dev_t);
293 static int __init root_dev_setup(char *line)
295 strlcpy(saved_root_name, line, sizeof(saved_root_name));
299 __setup("root=", root_dev_setup);
301 static int __init rootwait_setup(char *str)
309 __setup("rootwait", rootwait_setup);
311 static char * __initdata root_mount_data;
312 static int __init root_data_setup(char *str)
314 root_mount_data = str;
318 static char * __initdata root_fs_names;
319 static int __init fs_names_setup(char *str)
325 static unsigned int __initdata root_delay;
326 static int __init root_delay_setup(char *str)
328 root_delay = simple_strtoul(str, NULL, 0);
332 __setup("rootflags=", root_data_setup);
333 __setup("rootfstype=", fs_names_setup);
334 __setup("rootdelay=", root_delay_setup);
336 static void __init get_fs_names(char *page)
341 strcpy(page, root_fs_names);
347 int len = get_filesystem_list(page);
351 for (p = page-1; p; p = next) {
352 next = strchr(++p, '\n');
355 while ((*s++ = *p++) != '\n')
363 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
365 struct super_block *s;
366 int err = sys_mount(name, "/root", fs, flags, data);
371 s = current->fs->pwd.dentry->d_sb;
374 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
376 s->s_flags & MS_RDONLY ? " readonly" : "",
377 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
381 void __init mount_block_root(char *name, int flags)
383 struct page *page = alloc_page(GFP_KERNEL |
384 __GFP_NOTRACK_FALSE_POSITIVE);
385 char *fs_names = page_address(page);
388 char b[BDEVNAME_SIZE];
390 const char *b = name;
393 get_fs_names(fs_names);
395 for (p = fs_names; *p; p += strlen(p)+1) {
396 int err = do_mount_root(name, p, flags, root_mount_data);
405 * Allow the user to distinguish between failed sys_open
406 * and bad superblock on root device.
407 * and give them a list of the available devices
410 __bdevname(ROOT_DEV, b);
412 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
413 root_device_name, b, err);
414 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
416 printk_all_partitions();
417 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
418 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
419 "explicit textual name for \"root=\" boot option.\n");
421 panic("VFS: Unable to mount root fs on %s", b);
423 if (!(flags & MS_RDONLY)) {
428 printk("List of all partitions:\n");
429 printk_all_partitions();
430 printk("No filesystem could mount root, tried: ");
431 for (p = fs_names; *p; p += strlen(p)+1)
435 __bdevname(ROOT_DEV, b);
437 panic("VFS: Unable to mount root fs on %s", b);
442 #ifdef CONFIG_ROOT_NFS
444 #define NFSROOT_TIMEOUT_MIN 5
445 #define NFSROOT_TIMEOUT_MAX 30
446 #define NFSROOT_RETRY_MAX 5
448 static int __init mount_nfs_root(void)
450 char *root_dev, *root_data;
451 unsigned int timeout;
454 err = nfs_root_data(&root_dev, &root_data);
459 * The server or network may not be ready, so try several
460 * times. Stop after a few tries in case the client wants
461 * to fall back to other boot methods.
463 timeout = NFSROOT_TIMEOUT_MIN;
464 for (try = 1; ; try++) {
465 err = do_mount_root(root_dev, "nfs",
466 root_mountflags, root_data);
469 if (try > NFSROOT_RETRY_MAX)
472 /* Wait, in case the server refused us immediately */
475 if (timeout > NFSROOT_TIMEOUT_MAX)
476 timeout = NFSROOT_TIMEOUT_MAX;
482 #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD)
483 void __init change_floppy(char *fmt, ...)
485 struct termios termios;
491 vsprintf(buf, fmt, args);
493 fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
495 sys_ioctl(fd, FDEJECT, 0);
498 printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
499 fd = sys_open("/dev/console", O_RDWR, 0);
501 sys_ioctl(fd, TCGETS, (long)&termios);
502 termios.c_lflag &= ~ICANON;
503 sys_ioctl(fd, TCSETSF, (long)&termios);
505 termios.c_lflag |= ICANON;
506 sys_ioctl(fd, TCSETSF, (long)&termios);
512 void __init mount_root(void)
514 #ifdef CONFIG_ROOT_NFS
515 if (ROOT_DEV == Root_NFS) {
516 if (mount_nfs_root())
519 printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy.\n");
523 #ifdef CONFIG_BLK_DEV_FD
524 if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) {
525 /* rd_doload is 2 for a dual initrd/ramload setup */
527 if (rd_load_disk(1)) {
528 ROOT_DEV = Root_RAM1;
529 root_device_name = NULL;
532 change_floppy("root floppy");
537 int err = create_dev("/dev/root", ROOT_DEV);
540 pr_emerg("Failed to create /dev/root: %d\n", err);
541 mount_block_root("/dev/root", root_mountflags);
547 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
549 void __init prepare_namespace(void)
554 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
560 * wait for the known devices to complete their probing
562 * Note: this is a potential source of long boot delays.
563 * For example, it is not atypical to wait 5 seconds here
564 * for the touchpad of a laptop to initialize.
566 wait_for_device_probe();
570 if (saved_root_name[0]) {
571 root_device_name = saved_root_name;
572 if (!strncmp(root_device_name, "mtd", 3) ||
573 !strncmp(root_device_name, "ubi", 3)) {
574 mount_block_root(root_device_name, root_mountflags);
577 ROOT_DEV = name_to_dev_t(root_device_name);
578 if (strncmp(root_device_name, "/dev/", 5) == 0)
579 root_device_name += 5;
585 /* wait for any asynchronous scanning to complete */
586 if ((ROOT_DEV == 0) && root_wait) {
587 printk(KERN_INFO "Waiting for root device %s...\n",
589 while (driver_probe_done() != 0 ||
590 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
592 async_synchronize_full();
595 is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR;
597 if (is_floppy && rd_doload && rd_load_disk(0))
598 ROOT_DEV = Root_RAM0;
602 devtmpfs_mount("dev");
603 sys_mount(".", "/", NULL, MS_MOVE, NULL);
607 static bool is_tmpfs;
608 static struct dentry *rootfs_mount(struct file_system_type *fs_type,
609 int flags, const char *dev_name, void *data)
611 static unsigned long once;
612 void *fill = ramfs_fill_super;
614 if (test_and_set_bit(0, &once))
615 return ERR_PTR(-ENODEV);
617 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
618 fill = shmem_fill_super;
620 return mount_nodev(fs_type, flags, data, fill);
623 static struct file_system_type rootfs_fs_type = {
625 .mount = rootfs_mount,
626 .kill_sb = kill_litter_super,
629 int __init init_rootfs(void)
631 int err = register_filesystem(&rootfs_fs_type);
636 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
637 (!root_fs_names || strstr(root_fs_names, "tmpfs"))) {
641 err = init_ramfs_fs();
645 unregister_filesystem(&rootfs_fs_type);