From: Cyrill Gorcunov <gorcunov@openvz.org>
Date: Thu, 29 Nov 2012 03:19:19 +0000 (+1100)
Subject: fs, exportfs: escape nil dereference if no s_export_op present
X-Git-Tag: next-20121205~1^2~10
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d6fe8445a47bde2b99163cb12e0b1a33fec1eb37;p=karo-tx-linux.git

fs, exportfs: escape nil dereference if no s_export_op present

This routine will be used to generate a file handle in fdinfo output for
inotify subsystem, where if no s_export_op present the general
export_encode_fh should be used.  Thus add a test if s_export_op present
inside exportfs_encode_fh itself.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: James Bottomley <jbottomley@parallels.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matthew Helsley <matt.helsley@gmail.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@onelan.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index f1f1c59c2966..7fb6b190d75b 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -357,7 +357,7 @@ int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len,
 		 */
 		parent = p->d_inode;
 	}
-	if (nop->encode_fh)
+	if (nop && nop->encode_fh)
 		error = nop->encode_fh(inode, fid->raw, max_len, parent);
 	else
 		error = export_encode_fh(inode, fid, max_len, parent);