vfs: do_last(): check LOOKUP_DIRECTORY

Check for ENOTDIR before finishing open.  This allows this code to be shared
between O_CREAT and plain opens.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -2386,6 +2386,9 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 	error = -EISDIR;
 	if (S_ISDIR(nd->inode->i_mode))
 		goto exit;
+	error = -ENOTDIR;
+	if ((nd->flags & LOOKUP_DIRECTORY) && !nd->inode->i_op->lookup)
+		goto exit;
 ok:
 	if (!S_ISREG(nd->inode->i_mode))
 		will_truncate = 0;