Merge tag 'upstream-3.13-rc1' of git://git.infradead.org/linux-ubifs

[cascardo/linux.git] / init / do_mounts.c

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 816014c..a51cddc 100644 (file)
--- 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;
+}