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1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/module.h>
3#include <linux/sched.h>
4#include <linux/ctype.h>
5#include <linux/fd.h>
6#include <linux/tty.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>
14#include <linux/fs.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>
22
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>
28
29#include "do_mounts.h"
30
31int root_mountflags = MS_RDONLY | MS_SILENT;
32static char __initdata saved_root_name[64];
33static int root_wait;
34
35dev_t ROOT_DEV;
36
37static int __init load_ramdisk(char *str)
38{
39 pr_warn("ignoring the deprecated load_ramdisk= option\n");
40 return 1;
41}
42__setup("load_ramdisk=", load_ramdisk);
43
44static int __init readonly(char *str)
45{
46 if (*str)
47 return 0;
48 root_mountflags |= MS_RDONLY;
49 return 1;
50}
51
52static int __init readwrite(char *str)
53{
54 if (*str)
55 return 0;
56 root_mountflags &= ~MS_RDONLY;
57 return 1;
58}
59
60__setup("ro", readonly);
61__setup("rw", readwrite);
62
63static int __init root_dev_setup(char *line)
64{
65 strscpy(saved_root_name, line, sizeof(saved_root_name));
66 return 1;
67}
68
69__setup("root=", root_dev_setup);
70
71static int __init rootwait_setup(char *str)
72{
73 if (*str)
74 return 0;
75 root_wait = -1;
76 return 1;
77}
78
79__setup("rootwait", rootwait_setup);
80
81static int __init rootwait_timeout_setup(char *str)
82{
83 int sec;
84
85 if (kstrtoint(str, 0, &sec) || sec < 0) {
86 pr_warn("ignoring invalid rootwait value\n");
87 goto ignore;
88 }
89
90 if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) {
91 pr_warn("ignoring excessive rootwait value\n");
92 goto ignore;
93 }
94
95 return 1;
96
97ignore:
98 /* Fallback to indefinite wait */
99 root_wait = -1;
100
101 return 1;
102}
103
104__setup("rootwait=", rootwait_timeout_setup);
105
106static char * __initdata root_mount_data;
107static int __init root_data_setup(char *str)
108{
109 root_mount_data = str;
110 return 1;
111}
112
113static char * __initdata root_fs_names;
114static int __init fs_names_setup(char *str)
115{
116 root_fs_names = str;
117 return 1;
118}
119
120static unsigned int __initdata root_delay;
121static int __init root_delay_setup(char *str)
122{
123 root_delay = simple_strtoul(str, NULL, 0);
124 return 1;
125}
126
127__setup("rootflags=", root_data_setup);
128__setup("rootfstype=", fs_names_setup);
129__setup("rootdelay=", root_delay_setup);
130
131/* This can return zero length strings. Caller should check */
132static int __init split_fs_names(char *page, size_t size)
133{
134 int count = 1;
135 char *p = page;
136
137 strscpy(p, root_fs_names, size);
138 while (*p++) {
139 if (p[-1] == ',') {
140 p[-1] = '\0';
141 count++;
142 }
143 }
144
145 return count;
146}
147
148static int __init do_mount_root(const char *name, const char *fs,
149 const int flags, const void *data)
150{
151 struct super_block *s;
152 struct page *p = NULL;
153 char *data_page = NULL;
154 int ret;
155
156 if (data) {
157 /* init_mount() requires a full page as fifth argument */
158 p = alloc_page(GFP_KERNEL);
159 if (!p)
160 return -ENOMEM;
161 data_page = page_address(p);
162 /* zero-pad. init_mount() will make sure it's terminated */
163 strncpy(data_page, data, PAGE_SIZE);
164 }
165
166 ret = init_mount(name, "/root", fs, flags, data_page);
167 if (ret)
168 goto out;
169
170 init_chdir("/root");
171 s = current->fs->pwd.dentry->d_sb;
172 ROOT_DEV = s->s_dev;
173 printk(KERN_INFO
174 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
175 s->s_type->name,
176 sb_rdonly(s) ? " readonly" : "",
177 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
178
179out:
180 if (p)
181 put_page(p);
182 return ret;
183}
184
185void __init mount_root_generic(char *name, char *pretty_name, int flags)
186{
187 struct page *page = alloc_page(GFP_KERNEL);
188 char *fs_names = page_address(page);
189 char *p;
190 char b[BDEVNAME_SIZE];
191 int num_fs, i;
192
193 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
194 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
195 if (root_fs_names)
196 num_fs = split_fs_names(fs_names, PAGE_SIZE);
197 else
198 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
199retry:
200 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
201 int err;
202
203 if (!*p)
204 continue;
205 err = do_mount_root(name, p, flags, root_mount_data);
206 switch (err) {
207 case 0:
208 goto out;
209 case -EACCES:
210 case -EINVAL:
211#ifdef CONFIG_BLOCK
212 init_flush_fput();
213#endif
214 continue;
215 }
216 /*
217 * Allow the user to distinguish between failed sys_open
218 * and bad superblock on root device.
219 * and give them a list of the available devices
220 */
221 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
222 pretty_name, b, err);
223 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
224 printk_all_partitions();
225
226 if (root_fs_names)
227 num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
228 if (!num_fs)
229 pr_err("Can't find any bdev filesystem to be used for mount!\n");
230 else {
231 pr_err("List of all bdev filesystems:\n");
232 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
233 pr_err(" %s", p);
234 pr_err("\n");
235 }
236
237 panic("VFS: Unable to mount root fs on %s", b);
238 }
239 if (!(flags & SB_RDONLY)) {
240 flags |= SB_RDONLY;
241 goto retry;
242 }
243
244 printk("List of all partitions:\n");
245 printk_all_partitions();
246 printk("No filesystem could mount root, tried: ");
247 for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
248 printk(" %s", p);
249 printk("\n");
250 panic("VFS: Unable to mount root fs on \"%s\" or %s", pretty_name, b);
251out:
252 put_page(page);
253}
254
255#ifdef CONFIG_ROOT_NFS
256
257#define NFSROOT_TIMEOUT_MIN 5
258#define NFSROOT_TIMEOUT_MAX 30
259#define NFSROOT_RETRY_MAX 5
260
261static void __init mount_nfs_root(void)
262{
263 char *root_dev, *root_data;
264 unsigned int timeout;
265 int try;
266
267 if (nfs_root_data(&root_dev, &root_data))
268 goto fail;
269
270 /*
271 * The server or network may not be ready, so try several
272 * times. Stop after a few tries in case the client wants
273 * to fall back to other boot methods.
274 */
275 timeout = NFSROOT_TIMEOUT_MIN;
276 for (try = 1; ; try++) {
277 if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))
278 return;
279 if (try > NFSROOT_RETRY_MAX)
280 break;
281
282 /* Wait, in case the server refused us immediately */
283 ssleep(timeout);
284 timeout <<= 1;
285 if (timeout > NFSROOT_TIMEOUT_MAX)
286 timeout = NFSROOT_TIMEOUT_MAX;
287 }
288fail:
289 pr_err("VFS: Unable to mount root fs via NFS.\n");
290}
291#else
292static inline void mount_nfs_root(void)
293{
294}
295#endif /* CONFIG_ROOT_NFS */
296
297#ifdef CONFIG_CIFS_ROOT
298
299#define CIFSROOT_TIMEOUT_MIN 5
300#define CIFSROOT_TIMEOUT_MAX 30
301#define CIFSROOT_RETRY_MAX 5
302
303static void __init mount_cifs_root(void)
304{
305 char *root_dev, *root_data;
306 unsigned int timeout;
307 int try;
308
309 if (cifs_root_data(&root_dev, &root_data))
310 goto fail;
311
312 timeout = CIFSROOT_TIMEOUT_MIN;
313 for (try = 1; ; try++) {
314 if (!do_mount_root(root_dev, "cifs", root_mountflags,
315 root_data))
316 return;
317 if (try > CIFSROOT_RETRY_MAX)
318 break;
319
320 ssleep(timeout);
321 timeout <<= 1;
322 if (timeout > CIFSROOT_TIMEOUT_MAX)
323 timeout = CIFSROOT_TIMEOUT_MAX;
324 }
325fail:
326 pr_err("VFS: Unable to mount root fs via SMB.\n");
327}
328#else
329static inline void mount_cifs_root(void)
330{
331}
332#endif /* CONFIG_CIFS_ROOT */
333
334static bool __init fs_is_nodev(char *fstype)
335{
336 struct file_system_type *fs = get_fs_type(fstype);
337 bool ret = false;
338
339 if (fs) {
340 ret = !(fs->fs_flags & FS_REQUIRES_DEV);
341 put_filesystem(fs);
342 }
343
344 return ret;
345}
346
347static int __init mount_nodev_root(char *root_device_name)
348{
349 char *fs_names, *fstype;
350 int err = -EINVAL;
351 int num_fs, i;
352
353 fs_names = (void *)__get_free_page(GFP_KERNEL);
354 if (!fs_names)
355 return -EINVAL;
356 num_fs = split_fs_names(fs_names, PAGE_SIZE);
357
358 for (i = 0, fstype = fs_names; i < num_fs;
359 i++, fstype += strlen(fstype) + 1) {
360 if (!*fstype)
361 continue;
362 if (!fs_is_nodev(fstype))
363 continue;
364 err = do_mount_root(root_device_name, fstype, root_mountflags,
365 root_mount_data);
366 if (!err)
367 break;
368 }
369
370 free_page((unsigned long)fs_names);
371 return err;
372}
373
374#ifdef CONFIG_BLOCK
375static void __init mount_block_root(char *root_device_name)
376{
377 int err = create_dev("/dev/root", ROOT_DEV);
378
379 if (err < 0)
380 pr_emerg("Failed to create /dev/root: %d\n", err);
381 mount_root_generic("/dev/root", root_device_name, root_mountflags);
382}
383#else
384static inline void mount_block_root(char *root_device_name)
385{
386}
387#endif /* CONFIG_BLOCK */
388
389void __init mount_root(char *root_device_name)
390{
391 switch (ROOT_DEV) {
392 case Root_NFS:
393 mount_nfs_root();
394 break;
395 case Root_CIFS:
396 mount_cifs_root();
397 break;
398 case Root_Generic:
399 mount_root_generic(root_device_name, root_device_name,
400 root_mountflags);
401 break;
402 case 0:
403 if (root_device_name && root_fs_names &&
404 mount_nodev_root(root_device_name) == 0)
405 break;
406 fallthrough;
407 default:
408 mount_block_root(root_device_name);
409 break;
410 }
411}
412
413/* wait for any asynchronous scanning to complete */
414static void __init wait_for_root(char *root_device_name)
415{
416 ktime_t end;
417
418 if (ROOT_DEV != 0)
419 return;
420
421 pr_info("Waiting for root device %s...\n", root_device_name);
422
423 end = ktime_add_ms(ktime_get_raw(), root_wait);
424
425 while (!driver_probe_done() ||
426 early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {
427 msleep(5);
428 if (root_wait > 0 && ktime_after(ktime_get_raw(), end))
429 break;
430 }
431
432 async_synchronize_full();
433
434}
435
436static dev_t __init parse_root_device(char *root_device_name)
437{
438 int error;
439 dev_t dev;
440
441 if (!strncmp(root_device_name, "mtd", 3) ||
442 !strncmp(root_device_name, "ubi", 3))
443 return Root_Generic;
444 if (strcmp(root_device_name, "/dev/nfs") == 0)
445 return Root_NFS;
446 if (strcmp(root_device_name, "/dev/cifs") == 0)
447 return Root_CIFS;
448 if (strcmp(root_device_name, "/dev/ram") == 0)
449 return Root_RAM0;
450
451 error = early_lookup_bdev(root_device_name, &dev);
452 if (error) {
453 if (error == -EINVAL && root_wait) {
454 pr_err("Disabling rootwait; root= is invalid.\n");
455 root_wait = 0;
456 }
457 return 0;
458 }
459 return dev;
460}
461
462/*
463 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
464 */
465void __init prepare_namespace(void)
466{
467 if (root_delay) {
468 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
469 root_delay);
470 ssleep(root_delay);
471 }
472
473 /*
474 * wait for the known devices to complete their probing
475 *
476 * Note: this is a potential source of long boot delays.
477 * For example, it is not atypical to wait 5 seconds here
478 * for the touchpad of a laptop to initialize.
479 */
480 wait_for_device_probe();
481
482 md_run_setup();
483
484 if (saved_root_name[0])
485 ROOT_DEV = parse_root_device(saved_root_name);
486
487 if (initrd_load(saved_root_name))
488 goto out;
489
490 if (root_wait)
491 wait_for_root(saved_root_name);
492 mount_root(saved_root_name);
493out:
494 devtmpfs_mount();
495 init_mount(".", "/", NULL, MS_MOVE, NULL);
496 init_chroot(".");
497}
498
499static bool is_tmpfs;
500static int rootfs_init_fs_context(struct fs_context *fc)
501{
502 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
503 return shmem_init_fs_context(fc);
504
505 return ramfs_init_fs_context(fc);
506}
507
508struct file_system_type rootfs_fs_type = {
509 .name = "rootfs",
510 .init_fs_context = rootfs_init_fs_context,
511 .kill_sb = kill_litter_super,
512};
513
514void __init init_rootfs(void)
515{
516 if (IS_ENABLED(CONFIG_TMPFS)) {
517 if (!saved_root_name[0] && !root_fs_names)
518 is_tmpfs = true;
519 else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))
520 is_tmpfs = true;
521 }
522}
1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/module.h>
3#include <linux/sched.h>
4#include <linux/ctype.h>
5#include <linux/fd.h>
6#include <linux/tty.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/genhd.h>
12#include <linux/mount.h>
13#include <linux/device.h>
14#include <linux/init.h>
15#include <linux/fs.h>
16#include <linux/initrd.h>
17#include <linux/async.h>
18#include <linux/fs_struct.h>
19#include <linux/slab.h>
20#include <linux/ramfs.h>
21#include <linux/shmem_fs.h>
22
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>
28
29#include "do_mounts.h"
30
31int root_mountflags = MS_RDONLY | MS_SILENT;
32static char * __initdata root_device_name;
33static char __initdata saved_root_name[64];
34static int root_wait;
35
36dev_t ROOT_DEV;
37
38static int __init load_ramdisk(char *str)
39{
40 pr_warn("ignoring the deprecated load_ramdisk= option\n");
41 return 1;
42}
43__setup("load_ramdisk=", load_ramdisk);
44
45static int __init readonly(char *str)
46{
47 if (*str)
48 return 0;
49 root_mountflags |= MS_RDONLY;
50 return 1;
51}
52
53static int __init readwrite(char *str)
54{
55 if (*str)
56 return 0;
57 root_mountflags &= ~MS_RDONLY;
58 return 1;
59}
60
61__setup("ro", readonly);
62__setup("rw", readwrite);
63
64#ifdef CONFIG_BLOCK
65struct uuidcmp {
66 const char *uuid;
67 int len;
68};
69
70/**
71 * match_dev_by_uuid - callback for finding a partition using its uuid
72 * @dev: device passed in by the caller
73 * @data: opaque pointer to the desired struct uuidcmp to match
74 *
75 * Returns 1 if the device matches, and 0 otherwise.
76 */
77static int match_dev_by_uuid(struct device *dev, const void *data)
78{
79 const struct uuidcmp *cmp = data;
80 struct hd_struct *part = dev_to_part(dev);
81
82 if (!part->info)
83 goto no_match;
84
85 if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len))
86 goto no_match;
87
88 return 1;
89no_match:
90 return 0;
91}
92
93
94/**
95 * devt_from_partuuid - looks up the dev_t of a partition by its UUID
96 * @uuid_str: char array containing ascii UUID
97 *
98 * The function will return the first partition which contains a matching
99 * UUID value in its partition_meta_info struct. This does not search
100 * by filesystem UUIDs.
101 *
102 * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be
103 * extracted and used as an offset from the partition identified by the UUID.
104 *
105 * Returns the matching dev_t on success or 0 on failure.
106 */
107static dev_t devt_from_partuuid(const char *uuid_str)
108{
109 dev_t res = 0;
110 struct uuidcmp cmp;
111 struct device *dev = NULL;
112 struct gendisk *disk;
113 struct hd_struct *part;
114 int offset = 0;
115 bool clear_root_wait = false;
116 char *slash;
117
118 cmp.uuid = uuid_str;
119
120 slash = strchr(uuid_str, '/');
121 /* Check for optional partition number offset attributes. */
122 if (slash) {
123 char c = 0;
124 /* Explicitly fail on poor PARTUUID syntax. */
125 if (sscanf(slash + 1,
126 "PARTNROFF=%d%c", &offset, &c) != 1) {
127 clear_root_wait = true;
128 goto done;
129 }
130 cmp.len = slash - uuid_str;
131 } else {
132 cmp.len = strlen(uuid_str);
133 }
134
135 if (!cmp.len) {
136 clear_root_wait = true;
137 goto done;
138 }
139
140 dev = class_find_device(&block_class, NULL, &cmp,
141 &match_dev_by_uuid);
142 if (!dev)
143 goto done;
144
145 res = dev->devt;
146
147 /* Attempt to find the partition by offset. */
148 if (!offset)
149 goto no_offset;
150
151 res = 0;
152 disk = part_to_disk(dev_to_part(dev));
153 part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
154 if (part) {
155 res = part_devt(part);
156 put_device(part_to_dev(part));
157 }
158
159no_offset:
160 put_device(dev);
161done:
162 if (clear_root_wait) {
163 pr_err("VFS: PARTUUID= is invalid.\n"
164 "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
165 if (root_wait)
166 pr_err("Disabling rootwait; root= is invalid.\n");
167 root_wait = 0;
168 }
169 return res;
170}
171
172/**
173 * match_dev_by_label - callback for finding a partition using its label
174 * @dev: device passed in by the caller
175 * @data: opaque pointer to the label to match
176 *
177 * Returns 1 if the device matches, and 0 otherwise.
178 */
179static int match_dev_by_label(struct device *dev, const void *data)
180{
181 const char *label = data;
182 struct hd_struct *part = dev_to_part(dev);
183
184 if (part->info && !strcmp(label, part->info->volname))
185 return 1;
186
187 return 0;
188}
189#endif
190
191/*
192 * Convert a name into device number. We accept the following variants:
193 *
194 * 1) <hex_major><hex_minor> device number in hexadecimal represents itself
195 * no leading 0x, for example b302.
196 * 2) /dev/nfs represents Root_NFS (0xff)
197 * 3) /dev/<disk_name> represents the device number of disk
198 * 4) /dev/<disk_name><decimal> represents the device number
199 * of partition - device number of disk plus the partition number
200 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
201 * used when disk name of partitioned disk ends on a digit.
202 * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
203 * unique id of a partition if the partition table provides it.
204 * The UUID may be either an EFI/GPT UUID, or refer to an MSDOS
205 * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero-
206 * filled hex representation of the 32-bit "NT disk signature", and PP
207 * is a zero-filled hex representation of the 1-based partition number.
208 * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
209 * a partition with a known unique id.
210 * 8) <major>:<minor> major and minor number of the device separated by
211 * a colon.
212 * 9) PARTLABEL=<name> with name being the GPT partition label.
213 * MSDOS partitions do not support labels!
214 * 10) /dev/cifs represents Root_CIFS (0xfe)
215 *
216 * If name doesn't have fall into the categories above, we return (0,0).
217 * block_class is used to check if something is a disk name. If the disk
218 * name contains slashes, the device name has them replaced with
219 * bangs.
220 */
221
222dev_t name_to_dev_t(const char *name)
223{
224 char s[32];
225 char *p;
226 dev_t res = 0;
227 int part;
228
229#ifdef CONFIG_BLOCK
230 if (strncmp(name, "PARTUUID=", 9) == 0) {
231 name += 9;
232 res = devt_from_partuuid(name);
233 if (!res)
234 goto fail;
235 goto done;
236 } else if (strncmp(name, "PARTLABEL=", 10) == 0) {
237 struct device *dev;
238
239 dev = class_find_device(&block_class, NULL, name + 10,
240 &match_dev_by_label);
241 if (!dev)
242 goto fail;
243
244 res = dev->devt;
245 put_device(dev);
246 goto done;
247 }
248#endif
249
250 if (strncmp(name, "/dev/", 5) != 0) {
251 unsigned maj, min, offset;
252 char dummy;
253
254 if ((sscanf(name, "%u:%u%c", &maj, &min, &dummy) == 2) ||
255 (sscanf(name, "%u:%u:%u:%c", &maj, &min, &offset, &dummy) == 3)) {
256 res = MKDEV(maj, min);
257 if (maj != MAJOR(res) || min != MINOR(res))
258 goto fail;
259 } else {
260 res = new_decode_dev(simple_strtoul(name, &p, 16));
261 if (*p)
262 goto fail;
263 }
264 goto done;
265 }
266
267 name += 5;
268 res = Root_NFS;
269 if (strcmp(name, "nfs") == 0)
270 goto done;
271 res = Root_CIFS;
272 if (strcmp(name, "cifs") == 0)
273 goto done;
274 res = Root_RAM0;
275 if (strcmp(name, "ram") == 0)
276 goto done;
277
278 if (strlen(name) > 31)
279 goto fail;
280 strcpy(s, name);
281 for (p = s; *p; p++)
282 if (*p == '/')
283 *p = '!';
284 res = blk_lookup_devt(s, 0);
285 if (res)
286 goto done;
287
288 /*
289 * try non-existent, but valid partition, which may only exist
290 * after revalidating the disk, like partitioned md devices
291 */
292 while (p > s && isdigit(p[-1]))
293 p--;
294 if (p == s || !*p || *p == '0')
295 goto fail;
296
297 /* try disk name without <part number> */
298 part = simple_strtoul(p, NULL, 10);
299 *p = '\0';
300 res = blk_lookup_devt(s, part);
301 if (res)
302 goto done;
303
304 /* try disk name without p<part number> */
305 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
306 goto fail;
307 p[-1] = '\0';
308 res = blk_lookup_devt(s, part);
309 if (res)
310 goto done;
311
312fail:
313 return 0;
314done:
315 return res;
316}
317EXPORT_SYMBOL_GPL(name_to_dev_t);
318
319static int __init root_dev_setup(char *line)
320{
321 strlcpy(saved_root_name, line, sizeof(saved_root_name));
322 return 1;
323}
324
325__setup("root=", root_dev_setup);
326
327static int __init rootwait_setup(char *str)
328{
329 if (*str)
330 return 0;
331 root_wait = 1;
332 return 1;
333}
334
335__setup("rootwait", rootwait_setup);
336
337static char * __initdata root_mount_data;
338static int __init root_data_setup(char *str)
339{
340 root_mount_data = str;
341 return 1;
342}
343
344static char * __initdata root_fs_names;
345static int __init fs_names_setup(char *str)
346{
347 root_fs_names = str;
348 return 1;
349}
350
351static unsigned int __initdata root_delay;
352static int __init root_delay_setup(char *str)
353{
354 root_delay = simple_strtoul(str, NULL, 0);
355 return 1;
356}
357
358__setup("rootflags=", root_data_setup);
359__setup("rootfstype=", fs_names_setup);
360__setup("rootdelay=", root_delay_setup);
361
362static void __init get_fs_names(char *page)
363{
364 char *s = page;
365
366 if (root_fs_names) {
367 strcpy(page, root_fs_names);
368 while (*s++) {
369 if (s[-1] == ',')
370 s[-1] = '\0';
371 }
372 } else {
373 int len = get_filesystem_list(page);
374 char *p, *next;
375
376 page[len] = '\0';
377 for (p = page-1; p; p = next) {
378 next = strchr(++p, '\n');
379 if (*p++ != '\t')
380 continue;
381 while ((*s++ = *p++) != '\n')
382 ;
383 s[-1] = '\0';
384 }
385 }
386 *s = '\0';
387}
388
389static int __init do_mount_root(const char *name, const char *fs,
390 const int flags, const void *data)
391{
392 struct super_block *s;
393 struct page *p = NULL;
394 char *data_page = NULL;
395 int ret;
396
397 if (data) {
398 /* init_mount() requires a full page as fifth argument */
399 p = alloc_page(GFP_KERNEL);
400 if (!p)
401 return -ENOMEM;
402 data_page = page_address(p);
403 /* zero-pad. init_mount() will make sure it's terminated */
404 strncpy(data_page, data, PAGE_SIZE);
405 }
406
407 ret = init_mount(name, "/root", fs, flags, data_page);
408 if (ret)
409 goto out;
410
411 init_chdir("/root");
412 s = current->fs->pwd.dentry->d_sb;
413 ROOT_DEV = s->s_dev;
414 printk(KERN_INFO
415 "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n",
416 s->s_type->name,
417 sb_rdonly(s) ? " readonly" : "",
418 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
419
420out:
421 if (p)
422 put_page(p);
423 return ret;
424}
425
426void __init mount_block_root(char *name, int flags)
427{
428 struct page *page = alloc_page(GFP_KERNEL);
429 char *fs_names = page_address(page);
430 char *p;
431 char b[BDEVNAME_SIZE];
432
433 scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
434 MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
435 get_fs_names(fs_names);
436retry:
437 for (p = fs_names; *p; p += strlen(p)+1) {
438 int err = do_mount_root(name, p, flags, root_mount_data);
439 switch (err) {
440 case 0:
441 goto out;
442 case -EACCES:
443 case -EINVAL:
444 continue;
445 }
446 /*
447 * Allow the user to distinguish between failed sys_open
448 * and bad superblock on root device.
449 * and give them a list of the available devices
450 */
451 printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
452 root_device_name, b, err);
453 printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
454
455 printk_all_partitions();
456#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
457 printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify "
458 "explicit textual name for \"root=\" boot option.\n");
459#endif
460 panic("VFS: Unable to mount root fs on %s", b);
461 }
462 if (!(flags & SB_RDONLY)) {
463 flags |= SB_RDONLY;
464 goto retry;
465 }
466
467 printk("List of all partitions:\n");
468 printk_all_partitions();
469 printk("No filesystem could mount root, tried: ");
470 for (p = fs_names; *p; p += strlen(p)+1)
471 printk(" %s", p);
472 printk("\n");
473 panic("VFS: Unable to mount root fs on %s", b);
474out:
475 put_page(page);
476}
477
478#ifdef CONFIG_ROOT_NFS
479
480#define NFSROOT_TIMEOUT_MIN 5
481#define NFSROOT_TIMEOUT_MAX 30
482#define NFSROOT_RETRY_MAX 5
483
484static int __init mount_nfs_root(void)
485{
486 char *root_dev, *root_data;
487 unsigned int timeout;
488 int try, err;
489
490 err = nfs_root_data(&root_dev, &root_data);
491 if (err != 0)
492 return 0;
493
494 /*
495 * The server or network may not be ready, so try several
496 * times. Stop after a few tries in case the client wants
497 * to fall back to other boot methods.
498 */
499 timeout = NFSROOT_TIMEOUT_MIN;
500 for (try = 1; ; try++) {
501 err = do_mount_root(root_dev, "nfs",
502 root_mountflags, root_data);
503 if (err == 0)
504 return 1;
505 if (try > NFSROOT_RETRY_MAX)
506 break;
507
508 /* Wait, in case the server refused us immediately */
509 ssleep(timeout);
510 timeout <<= 1;
511 if (timeout > NFSROOT_TIMEOUT_MAX)
512 timeout = NFSROOT_TIMEOUT_MAX;
513 }
514 return 0;
515}
516#endif
517
518#ifdef CONFIG_CIFS_ROOT
519
520extern int cifs_root_data(char **dev, char **opts);
521
522#define CIFSROOT_TIMEOUT_MIN 5
523#define CIFSROOT_TIMEOUT_MAX 30
524#define CIFSROOT_RETRY_MAX 5
525
526static int __init mount_cifs_root(void)
527{
528 char *root_dev, *root_data;
529 unsigned int timeout;
530 int try, err;
531
532 err = cifs_root_data(&root_dev, &root_data);
533 if (err != 0)
534 return 0;
535
536 timeout = CIFSROOT_TIMEOUT_MIN;
537 for (try = 1; ; try++) {
538 err = do_mount_root(root_dev, "cifs", root_mountflags,
539 root_data);
540 if (err == 0)
541 return 1;
542 if (try > CIFSROOT_RETRY_MAX)
543 break;
544
545 ssleep(timeout);
546 timeout <<= 1;
547 if (timeout > CIFSROOT_TIMEOUT_MAX)
548 timeout = CIFSROOT_TIMEOUT_MAX;
549 }
550 return 0;
551}
552#endif
553
554void __init mount_root(void)
555{
556#ifdef CONFIG_ROOT_NFS
557 if (ROOT_DEV == Root_NFS) {
558 if (!mount_nfs_root())
559 printk(KERN_ERR "VFS: Unable to mount root fs via NFS.\n");
560 return;
561 }
562#endif
563#ifdef CONFIG_CIFS_ROOT
564 if (ROOT_DEV == Root_CIFS) {
565 if (!mount_cifs_root())
566 printk(KERN_ERR "VFS: Unable to mount root fs via SMB.\n");
567 return;
568 }
569#endif
570#ifdef CONFIG_BLOCK
571 {
572 int err = create_dev("/dev/root", ROOT_DEV);
573
574 if (err < 0)
575 pr_emerg("Failed to create /dev/root: %d\n", err);
576 mount_block_root("/dev/root", root_mountflags);
577 }
578#endif
579}
580
581/*
582 * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
583 */
584void __init prepare_namespace(void)
585{
586 if (root_delay) {
587 printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
588 root_delay);
589 ssleep(root_delay);
590 }
591
592 /*
593 * wait for the known devices to complete their probing
594 *
595 * Note: this is a potential source of long boot delays.
596 * For example, it is not atypical to wait 5 seconds here
597 * for the touchpad of a laptop to initialize.
598 */
599 wait_for_device_probe();
600
601 md_run_setup();
602
603 if (saved_root_name[0]) {
604 root_device_name = saved_root_name;
605 if (!strncmp(root_device_name, "mtd", 3) ||
606 !strncmp(root_device_name, "ubi", 3)) {
607 mount_block_root(root_device_name, root_mountflags);
608 goto out;
609 }
610 ROOT_DEV = name_to_dev_t(root_device_name);
611 if (strncmp(root_device_name, "/dev/", 5) == 0)
612 root_device_name += 5;
613 }
614
615 if (initrd_load())
616 goto out;
617
618 /* wait for any asynchronous scanning to complete */
619 if ((ROOT_DEV == 0) && root_wait) {
620 printk(KERN_INFO "Waiting for root device %s...\n",
621 saved_root_name);
622 while (driver_probe_done() != 0 ||
623 (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0)
624 msleep(5);
625 async_synchronize_full();
626 }
627
628 mount_root();
629out:
630 devtmpfs_mount();
631 init_mount(".", "/", NULL, MS_MOVE, NULL);
632 init_chroot(".");
633}
634
635static bool is_tmpfs;
636static int rootfs_init_fs_context(struct fs_context *fc)
637{
638 if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
639 return shmem_init_fs_context(fc);
640
641 return ramfs_init_fs_context(fc);
642}
643
644struct file_system_type rootfs_fs_type = {
645 .name = "rootfs",
646 .init_fs_context = rootfs_init_fs_context,
647 .kill_sb = kill_litter_super,
648};
649
650void __init init_rootfs(void)
651{
652 if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
653 (!root_fs_names || strstr(root_fs_names, "tmpfs")))
654 is_tmpfs = true;
655}