ext3: ensure fast symlinks are NUL-terminated

Ensure fast symlink targets are NUL-terminated, even if corrupted
on-disk.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: NDuane Griffin <duaneg@dghda.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/ext3/inode.c

@@ -37,6 +37,7 @@
 #include <linux/uio.h>
 #include <linux/bio.h>
 #include <linux/fiemap.h>
+#include <linux/namei.h>
 #include "xattr.h"
 #include "acl.h"
 
@@ -2817,9 +2818,11 @@ struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
 		inode->i_op = &ext3_dir_inode_operations;
 		inode->i_fop = &ext3_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
-		if (ext3_inode_is_fast_symlink(inode))
+		if (ext3_inode_is_fast_symlink(inode)) {
 			inode->i_op = &ext3_fast_symlink_inode_operations;
-		else {
+			nd_terminate_link(ei->i_data, inode->i_size,
+				sizeof(ei->i_data) - 1);
+		} else {
 			inode->i_op = &ext3_symlink_inode_operations;
 			ext3_set_aops(inode);
 		}