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