set_bad_inode now sets i_state because iput will BUG if it is set to I_CLEAR.
diff --git a/fs/bad_inode.c b/fs/bad_inode.c
new file mode 100644
index 0000000..fa3cf74
--- /dev/null
+++ b/fs/bad_inode.c
@@ -0,0 +1,109 @@
+/*
+ *  linux/fs/bad_inode.c
+ *
+ *  Copyright (C) 1997, Stephen Tweedie
+ *
+ *  Provide stub functions for unreadable inodes
+ */
+
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/sched.h>
+
+/*
+ * The follow_link operation is special: it must behave as a no-op
+ * so that a bad root inode can at least be unmounted. To do this
+ * we must dput() the base and return the dentry with a dget().
+ */
+static int bad_follow_link(struct dentry *dent, struct nameidata *nd)
+{
+	return vfs_follow_link(nd, ERR_PTR(-EIO));
+}
+
+static int return_EIO(void)
+{
+	return -EIO;
+}
+
+#define EIO_ERROR ((void *) (return_EIO))
+
+static struct file_operations bad_file_ops =
+{
+	llseek:		EIO_ERROR,
+	read:		EIO_ERROR,
+	write:		EIO_ERROR,
+	readdir:	EIO_ERROR,
+	poll:		EIO_ERROR,
+	ioctl:		EIO_ERROR,
+	mmap:		EIO_ERROR,
+	open:		EIO_ERROR,
+	flush:		EIO_ERROR,
+	release:	EIO_ERROR,
+	fsync:		EIO_ERROR,
+	fasync:		EIO_ERROR,
+	lock:		EIO_ERROR,
+};
+
+struct inode_operations bad_inode_ops =
+{
+	create:		EIO_ERROR,
+	lookup:		EIO_ERROR,
+	link:		EIO_ERROR,
+	unlink:		EIO_ERROR,
+	symlink:	EIO_ERROR,
+	mkdir:		EIO_ERROR,
+	rmdir:		EIO_ERROR,
+	mknod:		EIO_ERROR,
+	rename:		EIO_ERROR,
+	readlink:	EIO_ERROR,
+	follow_link:	bad_follow_link,
+	truncate:	EIO_ERROR,
+	permission:	EIO_ERROR,
+	revalidate:	EIO_ERROR,
+};
+
+
+/*
+ * When a filesystem is unable to read an inode due to an I/O error in
+ * its read_inode() function, it can call make_bad_inode() to return a
+ * set of stubs which will return EIO errors as required. 
+ *
+ * We only need to do limited initialisation: all other fields are
+ * preinitialised to zero automatically.
+ */
+ 
+/**
+ *	make_bad_inode - mark an inode bad due to an I/O error
+ *	@inode: Inode to mark bad
+ *
+ *	When an inode cannot be read due to a media or remote network
+ *	failure this function makes the inode "bad" and causes I/O operations
+ *	on it to fail from this point on.
+ */
+ 
+void make_bad_inode(struct inode * inode) 
+{
+	inode->i_state = 0;
+	inode->i_mode = S_IFREG;
+	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	inode->i_op = &bad_inode_ops;	
+	inode->i_fop = &bad_file_ops;	
+}
+
+/*
+ * This tests whether an inode has been flagged as bad. The test uses
+ * &bad_inode_ops to cover the case of invalidated inodes as well as
+ * those created by make_bad_inode() above.
+ */
+ 
+/**
+ *	is_bad_inode - is an inode errored
+ *	@inode: inode to test
+ *
+ *	Returns true if the inode in question has been marked as bad.
+ */
+ 
+int is_bad_inode(struct inode * inode) 
+{
+	return (inode->i_op == &bad_inode_ops);	
+}