diff options
Diffstat (limited to 'init/do_mounts.c')
| -rw-r--r-- | init/do_mounts.c | 254 |
1 files changed, 235 insertions, 19 deletions
diff --git a/init/do_mounts.c b/init/do_mounts.c index bb008d064c1..82f22885c87 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -1,3 +1,13 @@ +/* + * 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 + #include <linux/module.h> #include <linux/sched.h> #include <linux/ctype.h> @@ -15,6 +25,9 @@ #include <linux/initrd.h> #include <linux/async.h> #include <linux/fs_struct.h> +#include <linux/slab.h> +#include <linux/ramfs.h> +#include <linux/shmem_fs.h> #include <linux/nfs_fs.h> #include <linux/nfs_fs_sb.h> @@ -27,7 +40,7 @@ int __initdata rd_doload; /* 1 = load RAM disk, 0 = don't load */ int root_mountflags = MS_RDONLY | MS_SILENT; static char * __initdata root_device_name; static char __initdata saved_root_name[64]; -static int __initdata root_wait; +static int root_wait; dev_t ROOT_DEV; @@ -57,6 +70,115 @@ static int __init readwrite(char *str) __setup("ro", readonly); __setup("rw", readwrite); +#ifdef CONFIG_BLOCK +struct uuidcmp { + const char *uuid; + int len; +}; + +/** + * match_dev_by_uuid - callback for finding a partition using its uuid + * @dev: device passed in by the caller + * @data: opaque pointer to the desired struct uuidcmp to match + * + * Returns 1 if the device matches, and 0 otherwise. + */ +static int match_dev_by_uuid(struct device *dev, const void *data) +{ + const struct uuidcmp *cmp = data; + struct hd_struct *part = dev_to_part(dev); + + if (!part->info) + goto no_match; + + if (strncasecmp(cmp->uuid, part->info->uuid, cmp->len)) + goto no_match; + + return 1; +no_match: + return 0; +} + + +/** + * devt_from_partuuid - looks up the dev_t of a partition by its UUID + * @uuid_str: char array containing ascii UUID + * + * 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. + * + * If @uuid_str is followed by a "/PARTNROFF=%d", then the number will be + * extracted and used as an offset from the partition identified by the UUID. + * + * Returns the matching dev_t on success or 0 on failure. + */ +static dev_t devt_from_partuuid(const char *uuid_str) +{ + dev_t res = 0; + struct uuidcmp cmp; + struct device *dev = NULL; + struct gendisk *disk; + struct hd_struct *part; + int offset = 0; + bool clear_root_wait = false; + char *slash; + + cmp.uuid = uuid_str; + + slash = strchr(uuid_str, '/'); + /* Check for optional partition number offset attributes. */ + if (slash) { + char c = 0; + /* Explicitly fail on poor PARTUUID syntax. */ + if (sscanf(slash + 1, + "PARTNROFF=%d%c", &offset, &c) != 1) { + clear_root_wait = true; + goto done; + } + cmp.len = slash - uuid_str; + } else { + cmp.len = strlen(uuid_str); + } + + if (!cmp.len) { + clear_root_wait = true; + goto done; + } + + dev = class_find_device(&block_class, NULL, &cmp, + &match_dev_by_uuid); + if (!dev) + goto done; + + res = dev->devt; + + /* 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); +done: + if (clear_root_wait) { + pr_err("VFS: PARTUUID= is invalid.\n" + "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n"); + if (root_wait) + pr_err("Disabling rootwait; root= is invalid.\n"); + root_wait = 0; + } + return res; +} +#endif + /* * Convert a name into device number. We accept the following variants: * @@ -67,6 +189,16 @@ __setup("rw", readwrite); * 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. + * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the + * unique id of a partition if the partition table provides it. + * 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. + * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to + * a partition with a known unique id. + * 8) <major>:<minor> major and minor number of the device separated by + * a colon. * * 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 @@ -81,6 +213,16 @@ dev_t name_to_dev_t(char *name) dev_t res = 0; int part; +#ifdef CONFIG_BLOCK + if (strncmp(name, "PARTUUID=", 9) == 0) { + name += 9; + res = devt_from_partuuid(name); + if (!res) + goto fail; + goto done; + } +#endif + if (strncmp(name, "/dev/", 5) != 0) { unsigned maj, min; @@ -115,7 +257,7 @@ dev_t name_to_dev_t(char *name) goto done; /* - * try non-existant, but valid partition, which may only exist + * try non-existent, but valid partition, which may only exist * after revalidating the disk, like partitioned md devices */ while (p > s && isdigit(p[-1])) @@ -216,23 +358,27 @@ static void __init get_fs_names(char *page) static int __init do_mount_root(char *name, char *fs, int flags, void *data) { + struct super_block *s; int err = sys_mount(name, "/root", fs, flags, data); if (err) return err; sys_chdir("/root"); - ROOT_DEV = current->fs->pwd.mnt->mnt_sb->s_dev; - printk("VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", - current->fs->pwd.mnt->mnt_sb->s_type->name, - current->fs->pwd.mnt->mnt_sb->s_flags & MS_RDONLY ? - " readonly" : "", MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); + s = current->fs->pwd.dentry->d_sb; + ROOT_DEV = s->s_dev; + printk(KERN_INFO + "VFS: Mounted root (%s filesystem)%s on device %u:%u.\n", + s->s_type->name, + s->s_flags & MS_RDONLY ? " readonly" : "", + MAJOR(ROOT_DEV), MINOR(ROOT_DEV)); return 0; } void __init mount_block_root(char *name, int flags) { - char *fs_names = __getname_gfp(GFP_KERNEL - | __GFP_NOTRACK_FALSE_POSITIVE); + struct page *page = alloc_page(GFP_KERNEL | + __GFP_NOTRACK_FALSE_POSITIVE); + char *fs_names = page_address(page); char *p; #ifdef CONFIG_BLOCK char b[BDEVNAME_SIZE]; @@ -261,8 +407,8 @@ retry: #ifdef CONFIG_BLOCK __bdevname(ROOT_DEV, b); #endif - printk("VFS: Cannot open root device \"%s\" or %s\n", - root_device_name, b); + printk("VFS: Cannot open root device \"%s\" or %s: error %d\n", + root_device_name, b, err); printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); printk_all_partitions(); @@ -284,18 +430,45 @@ retry: #endif panic("VFS: Unable to mount root fs on %s", b); out: - putname(fs_names); + put_page(page); } #ifdef CONFIG_ROOT_NFS + +#define NFSROOT_TIMEOUT_MIN 5 +#define NFSROOT_TIMEOUT_MAX 30 +#define NFSROOT_RETRY_MAX 5 + static int __init mount_nfs_root(void) { - void *data = nfs_root_data(); + char *root_dev, *root_data; + unsigned int timeout; + int try, err; - create_dev("/dev/root", ROOT_DEV); - if (data && - do_mount_root("/dev/root", "nfs", root_mountflags, data) == 0) - return 1; + err = nfs_root_data(&root_dev, &root_data); + if (err != 0) + return 0; + + /* + * 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; } #endif @@ -333,7 +506,7 @@ void __init change_floppy(char *fmt, ...) void __init mount_root(void) { #ifdef CONFIG_ROOT_NFS - if (MAJOR(ROOT_DEV) == UNNAMED_MAJOR) { + if (ROOT_DEV == Root_NFS) { if (mount_nfs_root()) return; @@ -367,7 +540,7 @@ void __init prepare_namespace(void) int is_floppy; if (root_delay) { - printk(KERN_INFO "Waiting %dsec before mounting root device...\n", + printk(KERN_INFO "Waiting %d sec before mounting root device...\n", root_delay); ssleep(root_delay); } @@ -419,3 +592,46 @@ out: sys_mount(".", "/", NULL, MS_MOVE, NULL); sys_chroot("."); } + +static bool is_tmpfs; +static struct dentry *rootfs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + static unsigned long once; + void *fill = ramfs_fill_super; + + if (test_and_set_bit(0, &once)) + return ERR_PTR(-ENODEV); + + if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs) + fill = shmem_fill_super; + + return mount_nodev(fs_type, flags, data, fill); +} + +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; + + if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] && + (!root_fs_names || strstr(root_fs_names, "tmpfs"))) { + err = shmem_init(); + is_tmpfs = true; + } else { + err = init_ramfs_fs(); + } + + if (err) + unregister_filesystem(&rootfs_fs_type); + + return err; +} |