Fix nasty ncpfs symlink handling bug.

This bug could cause oopses and page state corruption, because ncpfs
used the generic page-cache symlink handlign functions.  But those
functions only work if the page cache is guaranteed to be "stable", ie a
page that was installed when the symlink walk was started has to still
be installed in the page cache at the end of the walk.

We could have fixed ncpfs to not use the generic helper routines, but it
is in many ways much cleaner to instead improve on the symlink walking
helper routines so that they don't require that absolute stability.

We do this by allowing "follow_link()" to return a error-pointer as a
cookie, which is fed back to the cleanup "put_link()" routine.  This
also simplifies NFS symlink handling.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/ext2/symlink.c b/fs/ext2/symlink.c
index 9f7bac01d55..1e67d87cfa9 100644
--- a/fs/ext2/symlink.c
+++ b/fs/ext2/symlink.c
@@ -21,11 +21,11 @@
 #include "xattr.h"
 #include <linux/namei.h>
 
-static int ext2_follow_link(struct dentry *dentry, struct nameidata *nd)
+static void *ext2_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
         struct ext2_inode_info *ei = EXT2_I(dentry->d_inode);
         nd_set_link(nd, (char *)ei->i_data);
-        return 0;
+        return NULL;
 }
 
 struct inode_operations ext2_symlink_inode_operations = {