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-rw-r--r--init/do_mounts.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 816014c4627e..a51cddc2ff8c 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -26,6 +26,8 @@
#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>
@@ -588,3 +590,46 @@ 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;
+}