From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7B72EC432C0 for ; Wed, 20 Nov 2019 15:46:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4434920709 for ; Wed, 20 Nov 2019 15:46:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="tSmjMhQW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732523AbfKTPqO (ORCPT ); Wed, 20 Nov 2019 10:46:14 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:59114 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732502AbfKTPqL (ORCPT ); Wed, 20 Nov 2019 10:46:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Y+r4uRt0HfEzC6FA94CrzjLBOB4pZm30/6RDjRbTH2g=; b=tSmjMhQWEB6+CN5nvKQYwrE4j KN9lA3Wy9FdbarML5HFOnBe/e5P+FIJNuzW/qZfMiWe8AAYY+17KukZlabN24ozKEMqVR6yr/CgUN V5RxLT241bf/rr2fd7497JpuAT5hQ0Tvl5dzLOvhVpsbu543my2G37XYlFxxR737pWXCLKiJeCnNw UPmEIM/qcuFPEOtrNXLHssgN5YfiEmEq/0ILBivrDgxVDqspH26C3K70zyBx6dxc6j5NGVl8olIwF 3Je8ZTgYWEvDuYtIg469g95Cyue9Mvu2MnRgBKJ6jrz4SvlO/zPwgwlnsF7Aqm3uriAzfK3z88Acv 01CiO8UcA==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1iXSAy-0003As-3v; Wed, 20 Nov 2019 15:45:52 +0000 Date: Wed, 20 Nov 2019 07:45:52 -0800 From: Matthew Wilcox To: zhengbin Cc: viro@zeniv.linux.org.uk, hughd@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, houtao1@huawei.com, yi.zhang@huawei.com Subject: Re: [PATCH] tmpfs: use ida to get inode number Message-ID: <20191120154552.GS20752@bombadil.infradead.org> References: <1574259798-144561-1-git-send-email-zhengbin13@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1574259798-144561-1-git-send-email-zhengbin13@huawei.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 20, 2019 at 10:23:18PM +0800, zhengbin wrote: > I have tried to change last_ino type to unsigned long, while this was > rejected, see details on https://patchwork.kernel.org/patch/11023915. Did you end up trying sbitmap? What I think is fundamentally wrong with this patch is that you've found a problem in get_next_ino() and decided to use a different scheme for this one filesystem, leaving every other filesystem which uses get_next_ino() facing the same problem. That could be acceptable if you explained why tmpfs is fundamentally different from all the other filesystems that use get_next_ino(), but you haven't (and I don't think there is such a difference. eg pipes, autofs and ipc mqueue could all have the same problem. There are some other problems I noticed, but they're not worth bringing up until this fundamental design choice is justified.