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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 3BF87C43219 for ; Tue, 30 Apr 2019 09:01:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0EA0821743 for ; Tue, 30 Apr 2019 09:01:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725790AbfD3JBG convert rfc822-to-8bit (ORCPT ); Tue, 30 Apr 2019 05:01:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48945 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725938AbfD3JBG (ORCPT ); Tue, 30 Apr 2019 05:01:06 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 69FC13097021 for ; Tue, 30 Apr 2019 09:01:06 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5DA281001DF6 for ; Tue, 30 Apr 2019 09:01:06 +0000 (UTC) Received: from zmail23.collab.prod.int.phx2.redhat.com (zmail23.collab.prod.int.phx2.redhat.com [10.5.83.28]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 5214E18089C9 for ; Tue, 30 Apr 2019 09:01:06 +0000 (UTC) Date: Tue, 30 Apr 2019 05:01:06 -0400 (EDT) From: Xiaoli Feng To: CIFS Message-ID: <151404631.6398428.1556614866154.JavaMail.zimbra@redhat.com> In-Reply-To: <1666985748.6396792.1556614132673.JavaMail.zimbra@redhat.com> Subject: Memory alignment requirement for Direct/IO MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.66.12.126, 10.4.195.22] Thread-Topic: Memory alignment requirement for Direct/IO Thread-Index: LoBIubb5eCZh1Y+FU+kTDfBZPxyGUA== X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Tue, 30 Apr 2019 09:01:06 +0000 (UTC) Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Hello, I setup samba server in upstream and mount it in local with cache=none,vers=3.11. Then test the Direct/IO function like this: fd=open(fname, O_DIRECT | O_RDWR | O_CREAT, 0666)) lseek(fd, 0, SEEK_SET); read(fd, buf, 1); For local filesystem such as XFS, "read" will be failed because XFS has 512Byte memory aligment for Direct/IO. But it's success for cifs. I don't know if it's expected. Could anybody tell me more about Direct/IO for cifs? Thanks. -- Best regards! XiaoLi Feng 冯小丽 Red Hat Software (Beijing) Co.,Ltd filesystem-qe Team IRC:xifeng，#channel: fs-qe Tel:+86-10-8388112 9/F, Raycom