do_last(): fix missing checks for LAST_BIND case

/proc/self/cwd with O_CREAT should fail with EISDIR.  /proc/self/exe, OTOH,
should fail with ENOTDIR when opened with O_DIRECTORY.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namei.c

@@ -2690,28 +2690,10 @@ static int do_last(struct nameidata *nd, struct path *path,
 	nd->flags &= ~LOOKUP_PARENT;
 	nd->flags |= op->intent;
 
-	switch (nd->last_type) {
-	case LAST_DOTDOT:
-	case LAST_DOT:
+	if (nd->last_type != LAST_NORM) {
 		error = handle_dots(nd, nd->last_type);
 		if (error)
 			return error;
-		/* fallthrough */
-	case LAST_ROOT:
-		error = complete_walk(nd);
-		if (error)
-			return error;
-		audit_inode(name, nd->path.dentry, 0);
-		if (open_flag & O_CREAT) {
-			error = -EISDIR;
-			goto out;
-		}
-		goto finish_open;
-	case LAST_BIND:
-		error = complete_walk(nd);
-		if (error)
-			return error;
-		audit_inode(name, dir, 0);
 		goto finish_open;
 	}
 
@@ -2841,19 +2823,19 @@ static int do_last(struct nameidata *nd, struct path *path,
 	}
 	nd->inode = inode;
 	/* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
+finish_open:
 	error = complete_walk(nd);
 	if (error) {
 		path_put(&save_parent);
 		return error;
 	}
+	audit_inode(name, nd->path.dentry, 0);
 	error = -EISDIR;
 	if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode))
 		goto out;
 	error = -ENOTDIR;
 	if ((nd->flags & LOOKUP_DIRECTORY) && !can_lookup(nd->inode))
 		goto out;
-	audit_inode(name, nd->path.dentry, 0);
-finish_open:
 	if (!S_ISREG(nd->inode->i_mode))
 		will_truncate = false;