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init/do_mounts.c
14.3 KB
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/* * Many of the syscalls used in this file expect some of the arguments * to be __user pointers not __kernel pointers. To limit the sparse * noise, turn off sparse checking for this file. */ #ifdef __CHECKER__ #undef __CHECKER__ #warning "Sparse checking disabled for this file" #endif |
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#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> |
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#include <linux/genhd.h> |
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#include <linux/mount.h> |
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#include <linux/device.h> |
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#include <linux/init.h> |
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#include <linux/fs.h> |
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#include <linux/initrd.h> |
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#include <linux/async.h> |
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#include <linux/fs_struct.h> |
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#include <linux/slab.h> |
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#include <linux/ramfs.h> |
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#include <linux/shmem_fs.h> |
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#include <linux/nfs_fs.h> #include <linux/nfs_fs_sb.h> #include <linux/nfs_mount.h> #include "do_mounts.h" |
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int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */ |
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int root_mountflags = MS_RDONLY | MS_SILENT; |
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static char * __initdata root_device_name; |
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static char __initdata saved_root_name[64]; |
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static int root_wait; |
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dev_t ROOT_DEV; |
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static int __init load_ramdisk(char *str) { rd_doload = simple_strtol(str,NULL,0) & 3; 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); |
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#ifdef CONFIG_BLOCK |
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struct uuidcmp { const char *uuid; int len; }; |
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/** * match_dev_by_uuid - callback for finding a partition using its uuid * @dev: device passed in by the caller |
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* @data: opaque pointer to the desired struct uuidcmp to match |
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* * Returns 1 if the device matches, and 0 otherwise. */ |
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static int match_dev_by_uuid(struct device *dev, const void *data) |
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{ |
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const struct uuidcmp *cmp = data; |
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struct hd_struct *part = dev_to_part(dev); if (!part->info) goto no_match; |
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if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len)) goto no_match; |
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return 1; no_match: return 0; } /** * devt_from_partuuid - looks up the dev_t of a partition by its UUID |
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* @uuid: char array containing ascii UUID |
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* * The function will return the first partition which contains a matching * UUID value in its partition_meta_info struct. This does not search * by filesystem UUIDs. * |
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* If @uuid is followed by a "/PARTNROFF=%d", then the number will be * extracted and used as an offset from the partition identified by the UUID. * |
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* Returns the matching dev_t on success or 0 on failure. */ |
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static dev_t devt_from_partuuid(const char *uuid_str) |
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{ dev_t res = 0; |
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struct uuidcmp cmp; |
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struct device *dev = NULL; |
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struct gendisk *disk; struct hd_struct *part; int offset = 0; |
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bool clear_root_wait = false; char *slash; |
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cmp.uuid = uuid_str; |
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|
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slash = strchr(uuid_str, '/'); |
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/* Check for optional partition number offset attributes. */ |
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if (slash) { |
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char c = 0; /* Explicitly fail on poor PARTUUID syntax. */ |
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if (sscanf(slash + 1, "PARTNROFF=%d%c", &offset, &c) != 1) { clear_root_wait = true; |
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goto done; } |
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cmp.len = slash - uuid_str; } else { cmp.len = strlen(uuid_str); } if (!cmp.len) { clear_root_wait = true; goto done; |
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} |
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dev = class_find_device(&block_class, NULL, &cmp, &match_dev_by_uuid); |
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if (!dev) goto done; res = dev->devt; |
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/* Attempt to find the partition by offset. */ if (!offset) goto no_offset; res = 0; disk = part_to_disk(dev_to_part(dev)); part = disk_get_part(disk, dev_to_part(dev)->partno + offset); if (part) { res = part_devt(part); put_device(part_to_dev(part)); } no_offset: put_device(dev); |
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done: |
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if (clear_root_wait) { pr_err("VFS: PARTUUID= is invalid. " "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d] "); if (root_wait) pr_err("Disabling rootwait; root= is invalid. "); root_wait = 0; } |
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return res; } |
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#endif |
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/* * Convert a name into device number. We accept the following variants: * * 1) device number in hexadecimal represents itself * 2) /dev/nfs represents Root_NFS (0xff) * 3) /dev/<disk_name> represents the device number of disk * 4) /dev/<disk_name><decimal> represents the device number * of partition - device number of disk plus the partition number * 5) /dev/<disk_name>p<decimal> - same as the above, that form is * used when disk name of partitioned disk ends on a digit. |
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* 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the * unique id of a partition if the partition table provides it. |
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* The UUID may be either an EFI/GPT UUID, or refer to an MSDOS * partition using the format SSSSSSSS-PP, where SSSSSSSS is a zero- * filled hex representation of the 32-bit "NT disk signature", and PP * is a zero-filled hex representation of the 1-based partition number. |
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* 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to * a partition with a known unique id. |
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* 8) <major>:<minor> major and minor number of the device separated by * a colon. |
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* |
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* If name doesn't have fall into the categories above, we return (0,0). * block_class is used to check if something is a disk name. If the disk * name contains slashes, the device name has them replaced with * bangs. |
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*/ dev_t name_to_dev_t(char *name) { char s[32]; char *p; dev_t res = 0; |
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int part; |
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#ifdef CONFIG_BLOCK |
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if (strncmp(name, "PARTUUID=", 9) == 0) { name += 9; |
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res = devt_from_partuuid(name); if (!res) goto fail; goto done; } |
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#endif |
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if (strncmp(name, "/dev/", 5) != 0) { unsigned maj, min; if (sscanf(name, "%u:%u", &maj, &min) == 2) { res = MKDEV(maj, min); if (maj != MAJOR(res) || min != MINOR(res)) goto fail; } else { res = new_decode_dev(simple_strtoul(name, &p, 16)); if (*p) goto fail; } goto done; } |
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name += 5; res = Root_NFS; if (strcmp(name, "nfs") == 0) goto done; res = Root_RAM0; if (strcmp(name, "ram") == 0) goto done; if (strlen(name) > 31) goto fail; strcpy(s, name); for (p = s; *p; p++) if (*p == '/') *p = '!'; |
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res = blk_lookup_devt(s, 0); if (res) goto done; /* |
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* try non-existent, but valid partition, which may only exist |
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* after revalidating the disk, like partitioned md devices */ while (p > s && isdigit(p[-1])) p--; if (p == s || !*p || *p == '0') goto fail; /* try disk name without <part number> */ part = simple_strtoul(p, NULL, 10); *p = '\0'; res = blk_lookup_devt(s, part); if (res) goto done; /* try disk name without p<part number> */ if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p') goto fail; p[-1] = '\0'; res = blk_lookup_devt(s, part); |
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if (res) goto done; |
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fail: return 0; |
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done: |
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return res; |
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} static int __init root_dev_setup(char *line) { strlcpy(saved_root_name, line, sizeof(saved_root_name)); return 1; } __setup("root=", root_dev_setup); |
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static int __init rootwait_setup(char *str) { if (*str) return 0; root_wait = 1; return 1; } __setup("rootwait", rootwait_setup); |
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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); static void __init get_fs_names(char *page) { char *s = page; if (root_fs_names) { strcpy(page, root_fs_names); while (*s++) { if (s[-1] == ',') s[-1] = '\0'; } } else { int len = get_filesystem_list(page); char *p, *next; page[len] = '\0'; for (p = page-1; p; p = next) { next = strchr(++p, ' '); if (*p++ != '\t') continue; while ((*s++ = *p++) != ' ') ; s[-1] = '\0'; } } *s = '\0'; } static int __init do_mount_root(char *name, char *fs, int flags, void *data) { |
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struct super_block *s; |
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int err = sys_mount(name, "/root", fs, flags, data); if (err) return err; |
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sys_chdir("/root"); |
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s = current->fs->pwd.dentry->d_sb; ROOT_DEV = s->s_dev; |
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printk(KERN_INFO "VFS: Mounted root (%s filesystem)%s on device %u:%u. ", |
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s->s_type->name, s->s_flags & MS_RDONLY ? " readonly" : "", MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); |
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return 0; } void __init mount_block_root(char *name, int flags) { |
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struct page *page = alloc_page(GFP_KERNEL | __GFP_NOTRACK_FALSE_POSITIVE); char *fs_names = page_address(page); |
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char *p; |
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#ifdef CONFIG_BLOCK |
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char b[BDEVNAME_SIZE]; |
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#else const char *b = name; #endif |
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get_fs_names(fs_names); retry: for (p = fs_names; *p; p += strlen(p)+1) { int err = do_mount_root(name, p, flags, root_mount_data); switch (err) { case 0: goto out; case -EACCES: flags |= MS_RDONLY; goto retry; case -EINVAL: continue; } /* * Allow the user to distinguish between failed sys_open * and bad superblock on root device. |
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* and give them a list of the available devices |
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*/ |
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#ifdef CONFIG_BLOCK |
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__bdevname(ROOT_DEV, b); |
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#endif |
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printk("VFS: Cannot open root device \"%s\" or %s: error %d ", root_device_name, b, err); |
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printk("Please append a correct \"root=\" boot option; here are the available partitions: "); |
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printk_all_partitions(); |
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#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " "explicit textual name for \"root=\" boot option. "); #endif |
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panic("VFS: Unable to mount root fs on %s", b); } |
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printk("List of all partitions: "); printk_all_partitions(); |
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printk("No filesystem could mount root, tried: "); for (p = fs_names; *p; p += strlen(p)+1) printk(" %s", p); printk(" "); |
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#ifdef CONFIG_BLOCK __bdevname(ROOT_DEV, b); #endif panic("VFS: Unable to mount root fs on %s", b); |
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out: |
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put_page(page); |
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} #ifdef CONFIG_ROOT_NFS |
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#define NFSROOT_TIMEOUT_MIN 5 #define NFSROOT_TIMEOUT_MAX 30 #define NFSROOT_RETRY_MAX 5 |
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static int __init mount_nfs_root(void) { |
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char *root_dev, *root_data; |
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unsigned int timeout; int try, err; |
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err = nfs_root_data(&root_dev, &root_data); if (err != 0) |
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return 0; |
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/* * 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++) { err = do_mount_root(root_dev, "nfs", root_mountflags, root_data); if (err == 0) return 1; 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; } return 0; |
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} #endif #if defined(CONFIG_BLK_DEV_RAM) || defined(CONFIG_BLK_DEV_FD) void __init change_floppy(char *fmt, ...) { struct termios termios; char buf[80]; char c; int fd; va_list args; va_start(args, fmt); vsprintf(buf, fmt, args); va_end(args); fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0); if (fd >= 0) { sys_ioctl(fd, FDEJECT, 0); sys_close(fd); } printk(KERN_NOTICE "VFS: Insert %s and press ENTER ", buf); fd = sys_open("/dev/console", O_RDWR, 0); if (fd >= 0) { sys_ioctl(fd, TCGETS, (long)&termios); termios.c_lflag &= ~ICANON; sys_ioctl(fd, TCSETSF, (long)&termios); sys_read(fd, &c, 1); termios.c_lflag |= ICANON; sys_ioctl(fd, TCSETSF, (long)&termios); sys_close(fd); } } #endif void __init mount_root(void) { #ifdef CONFIG_ROOT_NFS |
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if (ROOT_DEV == Root_NFS) { |
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if (mount_nfs_root()) return; printk(KERN_ERR "VFS: Unable to mount root fs via NFS, trying floppy. "); ROOT_DEV = Root_FD0; } #endif #ifdef CONFIG_BLK_DEV_FD if (MAJOR(ROOT_DEV) == FLOPPY_MAJOR) { /* rd_doload is 2 for a dual initrd/ramload setup */ if (rd_doload==2) { if (rd_load_disk(1)) { ROOT_DEV = Root_RAM1; root_device_name = NULL; } } else change_floppy("root floppy"); } #endif |
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#ifdef CONFIG_BLOCK |
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create_dev("/dev/root", ROOT_DEV); |
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mount_block_root("/dev/root", root_mountflags); |
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#endif |
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} /* * Prepare the namespace - decide what/where to mount, load ramdisks, etc. */ void __init prepare_namespace(void) { int is_floppy; |
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if (root_delay) { |
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printk(KERN_INFO "Waiting %d sec before mounting root device... ", |
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root_delay); ssleep(root_delay); } |
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/* * 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(); |
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md_run_setup(); if (saved_root_name[0]) { root_device_name = saved_root_name; |
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if (!strncmp(root_device_name, "mtd", 3) || !strncmp(root_device_name, "ubi", 3)) { |
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mount_block_root(root_device_name, root_mountflags); goto out; } |
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ROOT_DEV = name_to_dev_t(root_device_name); if (strncmp(root_device_name, "/dev/", 5) == 0) root_device_name += 5; } |
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if (initrd_load()) goto out; |
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/* wait for any asynchronous scanning to complete */ if ((ROOT_DEV == 0) && root_wait) { printk(KERN_INFO "Waiting for root device %s... ", saved_root_name); while (driver_probe_done() != 0 || (ROOT_DEV = name_to_dev_t(saved_root_name)) == 0) msleep(100); |
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async_synchronize_full(); |
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} is_floppy = MAJOR(ROOT_DEV) == FLOPPY_MAJOR; |
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if (is_floppy && rd_doload && rd_load_disk(0)) ROOT_DEV = Root_RAM0; mount_root(); out: |
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devtmpfs_mount("dev"); |
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sys_mount(".", "/", NULL, MS_MOVE, NULL); |
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sys_chroot("."); |
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} |
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static bool is_tmpfs; |
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static struct dentry *rootfs_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { static unsigned long once; |
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void *fill = ramfs_fill_super; |
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if (test_and_set_bit(0, &once)) return ERR_PTR(-ENODEV); |
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if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) fill = shmem_fill_super; return mount_nodev(fs_type, flags, data, fill); |
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} static struct file_system_type rootfs_fs_type = { .name = "rootfs", .mount = rootfs_mount, .kill_sb = kill_litter_super, }; int __init init_rootfs(void) { int err = register_filesystem(&rootfs_fs_type); if (err) return err; |
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if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && (!root_fs_names || strstr(root_fs_names, "tmpfs"))) { |
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err = shmem_init(); |
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is_tmpfs = true; } else { |
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err = init_ramfs_fs(); |
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} |
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if (err) unregister_filesystem(&rootfs_fs_type); return err; } |