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-rw-r--r--init/do_mounts.c519
1 files changed, 519 insertions, 0 deletions
diff --git a/init/do_mounts.c b/init/do_mounts.c
new file mode 100644
index 0000000000..21d065a55a
--- /dev/null
+++ b/init/do_mounts.c
@@ -0,0 +1,519 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#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>
+#include <linux/mount.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#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/ktime.h>
+
+#include <linux/nfs_fs.h>
+#include <linux/nfs_fs_sb.h>
+#include <linux/nfs_mount.h>
+#include <linux/raid/detect.h>
+#include <uapi/linux/mount.h>
+
+#include "do_mounts.h"
+
+int root_mountflags = MS_RDONLY | MS_SILENT;
+static char __initdata saved_root_name[64];
+static int root_wait;
+
+dev_t ROOT_DEV;
+
+static int __init load_ramdisk(char *str)
+{
+ pr_warn("ignoring the deprecated load_ramdisk= option\n");
+ 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);
+
+static int __init root_dev_setup(char *line)
+{
+ strscpy(saved_root_name, line, sizeof(saved_root_name));
+ return 1;
+}
+
+__setup("root=", root_dev_setup);
+
+static int __init rootwait_setup(char *str)
+{
+ if (*str)
+ return 0;
+ root_wait = -1;
+ return 1;
+}
+
+__setup("rootwait", rootwait_setup);
+
+static int __init rootwait_timeout_setup(char *str)
+{
+ int sec;
+
+ if (kstrtoint(str, 0, &sec) || sec < 0) {
+ pr_warn("ignoring invalid rootwait value\n");
+ goto ignore;
+ }
+
+ if (check_mul_overflow(sec, MSEC_PER_SEC, &root_wait)) {
+ pr_warn("ignoring excessive rootwait value\n");
+ goto ignore;
+ }
+
+ return 1;
+
+ignore:
+ /* Fallback to indefinite wait */
+ root_wait = -1;
+
+ return 1;
+}
+
+__setup("rootwait=", rootwait_timeout_setup);
+
+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);
+
+/* This can return zero length strings. Caller should check */
+static int __init split_fs_names(char *page, size_t size)
+{
+ int count = 1;
+ char *p = page;
+
+ strscpy(p, root_fs_names, size);
+ while (*p++) {
+ if (p[-1] == ',') {
+ p[-1] = '\0';
+ count++;
+ }
+ }
+
+ return count;
+}
+
+static int __init do_mount_root(const char *name, const char *fs,
+ const int flags, const void *data)
+{
+ struct super_block *s;
+ struct page *p = NULL;
+ char *data_page = NULL;
+ int ret;
+
+ if (data) {
+ /* init_mount() requires a full page as fifth argument */
+ p = alloc_page(GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ data_page = page_address(p);
+ /* zero-pad. init_mount() will make sure it's terminated */
+ strncpy(data_page, data, PAGE_SIZE);
+ }
+
+ ret = init_mount(name, "/root", fs, flags, data_page);
+ if (ret)
+ goto out;
+
+ init_chdir("/root");
+ 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,
+ sb_rdonly(s) ? " readonly" : "",
+ MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
+
+out:
+ if (p)
+ put_page(p);
+ return ret;
+}
+
+void __init mount_root_generic(char *name, char *pretty_name, int flags)
+{
+ struct page *page = alloc_page(GFP_KERNEL);
+ char *fs_names = page_address(page);
+ char *p;
+ char b[BDEVNAME_SIZE];
+ int num_fs, i;
+
+ scnprintf(b, BDEVNAME_SIZE, "unknown-block(%u,%u)",
+ MAJOR(ROOT_DEV), MINOR(ROOT_DEV));
+ if (root_fs_names)
+ num_fs = split_fs_names(fs_names, PAGE_SIZE);
+ else
+ num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
+retry:
+ for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1) {
+ int err;
+
+ if (!*p)
+ continue;
+ err = do_mount_root(name, p, flags, root_mount_data);
+ switch (err) {
+ case 0:
+ goto out;
+ case -EACCES:
+ case -EINVAL:
+ continue;
+ }
+ /*
+ * Allow the user to distinguish between failed sys_open
+ * and bad superblock on root device.
+ * and give them a list of the available devices
+ */
+ printk("VFS: Cannot open root device \"%s\" or %s: error %d\n",
+ pretty_name, b, err);
+ printk("Please append a correct \"root=\" boot option; here are the available partitions:\n");
+ printk_all_partitions();
+
+ if (root_fs_names)
+ num_fs = list_bdev_fs_names(fs_names, PAGE_SIZE);
+ if (!num_fs)
+ pr_err("Can't find any bdev filesystem to be used for mount!\n");
+ else {
+ pr_err("List of all bdev filesystems:\n");
+ for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
+ pr_err(" %s", p);
+ pr_err("\n");
+ }
+
+ panic("VFS: Unable to mount root fs on %s", b);
+ }
+ if (!(flags & SB_RDONLY)) {
+ flags |= SB_RDONLY;
+ goto retry;
+ }
+
+ printk("List of all partitions:\n");
+ printk_all_partitions();
+ printk("No filesystem could mount root, tried: ");
+ for (i = 0, p = fs_names; i < num_fs; i++, p += strlen(p)+1)
+ printk(" %s", p);
+ printk("\n");
+ panic("VFS: Unable to mount root fs on %s", b);
+out:
+ put_page(page);
+}
+
+#ifdef CONFIG_ROOT_NFS
+
+#define NFSROOT_TIMEOUT_MIN 5
+#define NFSROOT_TIMEOUT_MAX 30
+#define NFSROOT_RETRY_MAX 5
+
+static void __init mount_nfs_root(void)
+{
+ char *root_dev, *root_data;
+ unsigned int timeout;
+ int try;
+
+ if (nfs_root_data(&root_dev, &root_data))
+ goto fail;
+
+ /*
+ * 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++) {
+ if (!do_mount_root(root_dev, "nfs", root_mountflags, root_data))
+ return;
+ 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;
+ }
+fail:
+ pr_err("VFS: Unable to mount root fs via NFS.\n");
+}
+#else
+static inline void mount_nfs_root(void)
+{
+}
+#endif /* CONFIG_ROOT_NFS */
+
+#ifdef CONFIG_CIFS_ROOT
+
+#define CIFSROOT_TIMEOUT_MIN 5
+#define CIFSROOT_TIMEOUT_MAX 30
+#define CIFSROOT_RETRY_MAX 5
+
+static void __init mount_cifs_root(void)
+{
+ char *root_dev, *root_data;
+ unsigned int timeout;
+ int try;
+
+ if (cifs_root_data(&root_dev, &root_data))
+ goto fail;
+
+ timeout = CIFSROOT_TIMEOUT_MIN;
+ for (try = 1; ; try++) {
+ if (!do_mount_root(root_dev, "cifs", root_mountflags,
+ root_data))
+ return;
+ if (try > CIFSROOT_RETRY_MAX)
+ break;
+
+ ssleep(timeout);
+ timeout <<= 1;
+ if (timeout > CIFSROOT_TIMEOUT_MAX)
+ timeout = CIFSROOT_TIMEOUT_MAX;
+ }
+fail:
+ pr_err("VFS: Unable to mount root fs via SMB.\n");
+}
+#else
+static inline void mount_cifs_root(void)
+{
+}
+#endif /* CONFIG_CIFS_ROOT */
+
+static bool __init fs_is_nodev(char *fstype)
+{
+ struct file_system_type *fs = get_fs_type(fstype);
+ bool ret = false;
+
+ if (fs) {
+ ret = !(fs->fs_flags & FS_REQUIRES_DEV);
+ put_filesystem(fs);
+ }
+
+ return ret;
+}
+
+static int __init mount_nodev_root(char *root_device_name)
+{
+ char *fs_names, *fstype;
+ int err = -EINVAL;
+ int num_fs, i;
+
+ fs_names = (void *)__get_free_page(GFP_KERNEL);
+ if (!fs_names)
+ return -EINVAL;
+ num_fs = split_fs_names(fs_names, PAGE_SIZE);
+
+ for (i = 0, fstype = fs_names; i < num_fs;
+ i++, fstype += strlen(fstype) + 1) {
+ if (!*fstype)
+ continue;
+ if (!fs_is_nodev(fstype))
+ continue;
+ err = do_mount_root(root_device_name, fstype, root_mountflags,
+ root_mount_data);
+ if (!err)
+ break;
+ }
+
+ free_page((unsigned long)fs_names);
+ return err;
+}
+
+#ifdef CONFIG_BLOCK
+static void __init mount_block_root(char *root_device_name)
+{
+ int err = create_dev("/dev/root", ROOT_DEV);
+
+ if (err < 0)
+ pr_emerg("Failed to create /dev/root: %d\n", err);
+ mount_root_generic("/dev/root", root_device_name, root_mountflags);
+}
+#else
+static inline void mount_block_root(char *root_device_name)
+{
+}
+#endif /* CONFIG_BLOCK */
+
+void __init mount_root(char *root_device_name)
+{
+ switch (ROOT_DEV) {
+ case Root_NFS:
+ mount_nfs_root();
+ break;
+ case Root_CIFS:
+ mount_cifs_root();
+ break;
+ case Root_Generic:
+ mount_root_generic(root_device_name, root_device_name,
+ root_mountflags);
+ break;
+ case 0:
+ if (root_device_name && root_fs_names &&
+ mount_nodev_root(root_device_name) == 0)
+ break;
+ fallthrough;
+ default:
+ mount_block_root(root_device_name);
+ break;
+ }
+}
+
+/* wait for any asynchronous scanning to complete */
+static void __init wait_for_root(char *root_device_name)
+{
+ ktime_t end;
+
+ if (ROOT_DEV != 0)
+ return;
+
+ pr_info("Waiting for root device %s...\n", root_device_name);
+
+ end = ktime_add_ms(ktime_get_raw(), root_wait);
+
+ while (!driver_probe_done() ||
+ early_lookup_bdev(root_device_name, &ROOT_DEV) < 0) {
+ msleep(5);
+ if (root_wait > 0 && ktime_after(ktime_get_raw(), end))
+ break;
+ }
+
+ async_synchronize_full();
+
+}
+
+static dev_t __init parse_root_device(char *root_device_name)
+{
+ int error;
+ dev_t dev;
+
+ if (!strncmp(root_device_name, "mtd", 3) ||
+ !strncmp(root_device_name, "ubi", 3))
+ return Root_Generic;
+ if (strcmp(root_device_name, "/dev/nfs") == 0)
+ return Root_NFS;
+ if (strcmp(root_device_name, "/dev/cifs") == 0)
+ return Root_CIFS;
+ if (strcmp(root_device_name, "/dev/ram") == 0)
+ return Root_RAM0;
+
+ error = early_lookup_bdev(root_device_name, &dev);
+ if (error) {
+ if (error == -EINVAL && root_wait) {
+ pr_err("Disabling rootwait; root= is invalid.\n");
+ root_wait = 0;
+ }
+ return 0;
+ }
+ return dev;
+}
+
+/*
+ * Prepare the namespace - decide what/where to mount, load ramdisks, etc.
+ */
+void __init prepare_namespace(void)
+{
+ if (root_delay) {
+ printk(KERN_INFO "Waiting %d sec before mounting root device...\n",
+ root_delay);
+ ssleep(root_delay);
+ }
+
+ /*
+ * 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();
+
+ md_run_setup();
+
+ if (saved_root_name[0])
+ ROOT_DEV = parse_root_device(saved_root_name);
+
+ if (initrd_load(saved_root_name))
+ goto out;
+
+ if (root_wait)
+ wait_for_root(saved_root_name);
+ mount_root(saved_root_name);
+out:
+ devtmpfs_mount();
+ init_mount(".", "/", NULL, MS_MOVE, NULL);
+ init_chroot(".");
+}
+
+static bool is_tmpfs;
+static int rootfs_init_fs_context(struct fs_context *fc)
+{
+ if (IS_ENABLED(CONFIG_TMPFS) && is_tmpfs)
+ return shmem_init_fs_context(fc);
+
+ return ramfs_init_fs_context(fc);
+}
+
+struct file_system_type rootfs_fs_type = {
+ .name = "rootfs",
+ .init_fs_context = rootfs_init_fs_context,
+ .kill_sb = kill_litter_super,
+};
+
+void __init init_rootfs(void)
+{
+ if (IS_ENABLED(CONFIG_TMPFS)) {
+ if (!saved_root_name[0] && !root_fs_names)
+ is_tmpfs = true;
+ else if (root_fs_names && !!strstr(root_fs_names, "tmpfs"))
+ is_tmpfs = true;
+ }
+}