tree 2d0af7b870f0c56a4b81938a65276565e8b0ac2b
parent 340a0a01b9675a16201cc4fc4a210eb5b3bc11ce
author Pavel Shilovsky <piastryyy@gmail.com> 1311602350 +0400
committer Al Viro <viro@zeniv.linux.org.uk> 1311618201 -0400

CIFS: Fix oops while mounting with prefixpath

commit fec11dd9a0109fe52fd631e5c510778d6cbff6cc caused
a regression when we have already mounted //server/share/a
and want to mount //server/share/a/b.

The problem is that lookup_one_len calls __lookup_hash
with nd pointer as NULL. Then __lookup_hash calls
do_revalidate in the case when dentry exists and we end
up with NULL pointer deference in cifs_d_revalidate:

if (nd->flags & LOOKUP_RCU)
	return -ECHILD;

Fix this by checking nd for NULL.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>