[PATCH] fix oops in namespace.c

Number four in the series of namespace.c fixes:

A familar type of Oops: d_path() can return an error ENAMETOOLONG,
and if we fail to test a segfault occurs.

So we must test. What we do is a different matter.
Rather arbitrarily I return the string " (too long)"
for use in /proc/mounts.

Andries

--- namespace.c~	Mon May 19 01:50:48 2003
+++ namespace.c	Mon May 19 01:51:24 2003
@@ -217,6 +217,8 @@
 	if (!path_buf)
 		return -ENOMEM;
 	path = d_path(mnt->mnt_root, mnt, path_buf, PAGE_SIZE);
+	if (IS_ERR(path))
+		path = " (too long)";
 
 	mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
 	seq_putc(m, ' ');