initmpfs: replace MS_NOUSER in initramfs

Mounting MS_NOUSER prevents --bind mounts from rootfs. Prevent new rootfs mounts with a different mechanism that doesn't affect bind mounts. Signed-off-by: Rob Landley <[email protected]> Cc: Jeff Layton <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Stephen Warren <[email protected]> Cc: Rusty Russell <[email protected]> Cc: Jim Cromie <[email protected]> Cc: Sam Ravnborg <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Alexander Viro <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
CamonZ · Sep 11, 2013 · 137fdcc · 137fdcc
1 parent 5e4c0d9
commit 137fdcc
Showing 1 changed file with 6 additions and 1 deletion.
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
@@ -247,7 +247,12 @@ struct dentry *ramfs_mount(struct file_system_type *fs_type,
 static struct dentry *rootfs_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data)
 {
-	return mount_nodev(fs_type, flags|MS_NOUSER, data, ramfs_fill_super);
+	static unsigned long once;
+
+	if (test_and_set_bit(1, &once))
+		return ERR_PTR(-ENODEV);
+
+	return mount_nodev(fs_type, flags, data, ramfs_fill_super);
 }
 
 static void ramfs_kill_sb(struct super_block *sb)