From: Pavel Shilovsky <piastryyy@gmail.com>
Date: Mon, 25 Jul 2011 13:59:10 +0000 (+0400)
Subject: CIFS: Fix oops while mounting with prefixpath
X-Git-Tag: v3.1-rc1~246^2~9
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3ca30d40a91fb9b9871e61d5dea2c1a895906a15;p=pandora-kernel.git

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>
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