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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 CEDFCC43603 for ; Tue, 17 Dec 2019 00:20:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 942AB2072D for ; Tue, 17 Dec 2019 00:20:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="nMNfACQt"; dkim=pass (1024-bit key) header.d=sharedspace.onmicrosoft.com header.i=@sharedspace.onmicrosoft.com header.b="vdkScfI3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727858AbfLQAUL (ORCPT ); Mon, 16 Dec 2019 19:20:11 -0500 Received: from esa4.hgst.iphmx.com ([216.71.154.42]:35179 "EHLO esa4.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727731AbfLQAUL (ORCPT ); Mon, 16 Dec 2019 19:20:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1576542010; x=1608078010; h=from:to:cc:subject:date:message-id:references: content-transfer-encoding:mime-version; bh=CglR53AJjw97zWHjLxXhhNbD+ff1664RlYk323EtHM8=; b=nMNfACQtfXrzbZ9NU29yj+dit1LqrKTbe8ysi5XfV+SH0TPSO9RTGV3T beIfIFWV+zwab9dHeNs3py+nmempHNs0b8dreH9ohRwgiEQFgrx0EklY1 F0zlDIn1aIiVaChJFYUELIBf/OXFyTD1Qb8Po8B2yxuPTfcpPyScUOKzn pu63KiddxsMecrPrwQtHvelDv/9TOKSqGMiSe53mVDPrqWDYg2s0q6Q5x H/wRsS6/x8YR6P6a4OWsdCT0Fy0UhvVlVO0cHUgx5fKESdHjinfydZXm5 PqeTZ6ShxvUjZw70sDd1+FQcUTKzFoj/yyxKv5bKmHM1Jrxj7c0783vWX g==; IronPort-SDR: CzKUQwm/OuKzuGHuZjT2XWbw+P47xXntEfdQwsSuQOCjaCUGCRhuI7ZwhHYDtdRsiPDJBteZX8 tJ7PXcJwVNh82s4+bwybHQGuqDYq8dh/SD1kNJefh9EdN84iABZLtNzVpGXZM2LiZB/+YTbw7M 5s+d7xJU2bjdmdLgH8+0/su/JfazdGDMQqQWw/LenH6rO30uF7bomCGfUkyLf1AjEWirFO3YzZ aynSSgr2xiJIkBQo3llsKY1Xv1Gd5f9Xa8+XFHNGO6N0XB4vFE4+DWZXZ/jzJ579ST9hEXavLF Yy4= X-IronPort-AV: E=Sophos;i="5.69,323,1571673600"; d="scan'208";a="125486370" Received: from mail-bl2nam02lp2050.outbound.protection.outlook.com (HELO NAM02-BL2-obe.outbound.protection.outlook.com) ([104.47.38.50]) by ob1.hgst.iphmx.com with ESMTP; 17 Dec 2019 08:20:09 +0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=n/xQuHQ7eraytt2fB6sKMykyI2h7HDkOVfSnB/JHAkPD+vcMC245amggiDdSsBCoE8jY8x3KXjTde5tljJ6nIy7rx/QM6GRrdmfeBHjvPZfM5t+VwC+3or2S6E9K+MCfVBrNXkcQyuZXpiMQ1Jl9h1hNXJZoWLrtJjo6LC4HVAExHx+DKmRjHJNujQP+jaWE3ZLm3kt/8dAoueLiyOWr/qDvA2Ifam0v10awm37lQ1NQeq3gDncpz6Yop5whLkYPmFx6A+sGg6RsnT1gpJlfzHc9ZiZ0EedpmEjli++pEedPHWoarvb1+cGnt86Rm9LOqDF232NSsWeAYojiuRWYjQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=nyVjP70TC9CKz680hAy9ZKK2us3a2t54jvKJGtGwhtg=; b=IlucVh3NRCbAiKbPhkzzcY44RZpRr2MqlE9NYIIg8ud8XOhEhhJt+y++aoKlz0+VSoNmOTk9jEaKxYwL3wwm+h06CszPvNeKrMGJC3qUvl/4n+WarSCqZu7l/VhLZ/6OOqfkhiqT8WKnlzwiqsqEF2fu5N6thnvDIRNnBDFzxUAyg7+zWB67joOc9OZIEK4kB/NJsHprEJi3ad9FvWYdrgfYMODLBzX/B6gzM0vmeTu1/f6/ohqNWeZ0A46cPUy8AYvrZouSOMIEGgM1k0tSh51lds4HZ6V1IVakDWcj0o5RF9kyNHir/y6OVq5ok9A7jV9YPlzCF+7JeS4ztTui7g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=wdc.com; dmarc=pass action=none header.from=wdc.com; dkim=pass header.d=wdc.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sharedspace.onmicrosoft.com; s=selector2-sharedspace-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=nyVjP70TC9CKz680hAy9ZKK2us3a2t54jvKJGtGwhtg=; b=vdkScfI3Ab2PjJ/rf5QIKX00uS9TcdZuXAxy0rtYVJEBoYwFay3CP/wwNig0qFNm+usEJWwOzAA9C7VeQKlfTfSWLkNNj48AHt1ASKtyZ1Tn9hontbU88gYVCy8XEUmcADQXcvd3wq4oVwEljDyP3UJ2z1R5TcVkob7wGmThmzc= Received: from BYAPR04MB5816.namprd04.prod.outlook.com (20.179.59.16) by BYAPR04MB5462.namprd04.prod.outlook.com (20.178.48.147) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2538.18; Tue, 17 Dec 2019 00:20:07 +0000 Received: from BYAPR04MB5816.namprd04.prod.outlook.com ([fe80::cd8e:d1de:e661:a61]) by BYAPR04MB5816.namprd04.prod.outlook.com ([fe80::cd8e:d1de:e661:a61%5]) with mapi id 15.20.2538.019; Tue, 17 Dec 2019 00:20:07 +0000 From: Damien Le Moal To: Hannes Reinecke , "linux-fsdevel@vger.kernel.org" , "linux-xfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Linus Torvalds CC: Johannes Thumshirn , Naohiro Aota , "Darrick J . Wong" Subject: Re: [PATCH 1/2] fs: New zonefs file system Thread-Topic: [PATCH 1/2] fs: New zonefs file system Thread-Index: AQHVsRtc4OoccT74tkyETJa3Ywntvw== Date: Tue, 17 Dec 2019 00:20:07 +0000 Message-ID: References: <20191212183816.102402-1-damien.lemoal@wdc.com> <20191212183816.102402-2-damien.lemoal@wdc.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Damien.LeMoal@wdc.com; x-originating-ip: [199.255.47.7] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: 5707b9e6-ac58-42dd-3960-08d78286df3b x-ms-traffictypediagnostic: BYAPR04MB5462: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: wdcipoutbound: EOP-TRUE x-ms-oob-tlc-oobclassifiers: OLM:6430; x-forefront-prvs: 02543CD7CD x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(4636009)(136003)(346002)(396003)(376002)(366004)(39860400002)(189003)(199004)(66946007)(33656002)(76116006)(91956017)(66476007)(64756008)(86362001)(66446008)(186003)(54906003)(5660300002)(26005)(66556008)(71200400001)(316002)(110136005)(2906002)(81166006)(81156014)(8676002)(4326008)(478600001)(9686003)(55016002)(6506007)(53546011)(52536014)(7696005)(8936002);DIR:OUT;SFP:1102;SCL:1;SRVR:BYAPR04MB5462;H:BYAPR04MB5816.namprd04.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: kauSOUlE7AyDyhsshnTOsf25yqnUsbbcBGZaiFtxSHc9HiY2rjAO7yq1Or0GT9la/fG4BqkOHQJD7JvC9LXb6rRVwCEN0v8GSSj6yreM7NA0DxXdQiMG5rhcF5+IxpSxaZTcctokD8ZxX3O+UUXPrvdZqF0UO7u0Ag6OChZlRnSkWlrdjVYaR2hs6CTogktLO4duFHC9iGi/ltSpGCPd+8EUG3dOX5MpE1zWUSxOVJcltpjD4xZNyfFt3n0NiSHSu67OBB3SMZ/+IIw8bgh8WIa8AcfXTFS05BbKByd50tEFcs91qxo9u/nwU3GVap2osF2F8luHmjb5DROADNSg1vxsbzGxTyIYUwVvAP2Nrrbt1ZUX2WlkP/3t7STiaVbDScQllwUMmUvJqlzpi6161uWllxO3ICFhV3yTf2ReoBprinaFsYdGg0558cfu+eoj Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5707b9e6-ac58-42dd-3960-08d78286df3b X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Dec 2019 00:20:07.7114 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: vnaoDn0D44eMeP+6SzQnB/XWUa8UvJvlYLIvIUFLX8rRIKewQ4utxD/mQ7WnWUQQk0lK7Ay2wcn5VBDaAW4VRg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR04MB5462 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/12/16 17:36, Hannes Reinecke wrote:=0A= [...]=0A= >> +static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_= t length,=0A= >> + unsigned int flags, struct iomap *iomap,=0A= >> + struct iomap *srcmap)=0A= >> +{=0A= >> + struct zonefs_sb_info *sbi =3D ZONEFS_SB(inode->i_sb);=0A= >> + struct zonefs_inode_info *zi =3D ZONEFS_I(inode);=0A= >> + loff_t max_isize =3D zi->i_max_size;=0A= >> + loff_t isize;=0A= >> +=0A= >> + /*=0A= >> + * For sequential zones, enforce direct IO writes. This is already=0A= >> + * checked when writes are issued, so warn about this here if we=0A= >> + * get buffered write to a sequential file inode.=0A= >> + */=0A= >> + if (WARN_ON_ONCE(zi->i_ztype =3D=3D ZONEFS_ZTYPE_SEQ &&=0A= >> + (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)))=0A= >> + return -EIO;=0A= >> +=0A= >> + /*=0A= >> + * For all zones, all blocks are always mapped. For sequential zones,= =0A= >> + * all blocks after the write pointer (inode size) are always unwritte= n.=0A= >> + */=0A= >> + mutex_lock(&zi->i_truncate_mutex);=0A= >> + isize =3D i_size_read(inode);=0A= >> + if (offset >=3D isize) {=0A= >> + length =3D min(length, max_isize - offset);=0A= >> + if (zi->i_ztype =3D=3D ZONEFS_ZTYPE_CNV)=0A= >> + iomap->type =3D IOMAP_MAPPED;=0A= >> + else=0A= >> + iomap->type =3D IOMAP_UNWRITTEN;=0A= >> + } else {=0A= >> + length =3D min(length, isize - offset);=0A= >> + iomap->type =3D IOMAP_MAPPED;=0A= >> + }=0A= >> + mutex_unlock(&zi->i_truncate_mutex);=0A= >> +=0A= >> + iomap->offset =3D offset & (~sbi->s_blocksize_mask);=0A= >> + iomap->length =3D ((offset + length + sbi->s_blocksize_mask) &=0A= >> + (~sbi->s_blocksize_mask)) - iomap->offset;=0A= >> + iomap->bdev =3D inode->i_sb->s_bdev;=0A= >> + iomap->addr =3D (zi->i_zsector << SECTOR_SHIFT) + iomap->offset;=0A= >> +=0A= >> + return 0;=0A= >> +}=0A= >> +=0A= >> +static const struct iomap_ops zonefs_iomap_ops =3D {=0A= >> + .iomap_begin =3D zonefs_iomap_begin,=0A= >> +};=0A= >> +=0A= > This probably shows my complete ignorance, but what is the effect on =0A= > enforcing the direct I/O writes on the pagecache?=0A= > IE what happens for buffered reads? Will the pages be invalidated when a = =0A= > write has been issued?=0A= =0A= Yes, a direct write issued to a file range that has cached pages result=0A= in these pages to be invalidated. But note that in the case of zonefs,=0A= this can happen only in the case of conventional zones. For sequential=0A= zones, this does not happen: reads can be buffered and cache pages but=0A= only for pages below the write pointer. And writes can only be issued at=0A= the write pointer. So there is never any possible overlap between=0A= buffered reads and direct writes.=0A= =0A= > Or do we simply rely on upper layers to ensure no concurrent buffered =0A= > and direct I/O is being made?=0A= =0A= Nope. VFS, or the file system specific implementation, takes care of=0A= that. See generic_file_direct_write() and its call to=0A= invalidate_inode_pages2_range().=0A= =0A= > =0A= > [ .. ]=0A= >> +=0A= >> +static int zonefs_seq_file_truncate(struct inode *inode, loff_t isize)= =0A= >> +{=0A= >> + struct zonefs_inode_info *zi =3D ZONEFS_I(inode);=0A= >> + loff_t old_isize;=0A= >> + enum req_opf op;=0A= >> + int ret =3D 0;=0A= >> +=0A= >> + /*=0A= >> + * For sequential zone files, we can only allow truncating to 0 size,= =0A= >> + * which is equivalent to a zone reset, or to the maximum file size,= =0A= >> + * which is equivalent toa zone finish.=0A= > =0A= > Spelling: to a=0A= =0A= Good catch. Will fix it. Thanks.=0A= =0A= > =0A= > [ .. ]=0A= > =0A= > Other than that:=0A= > Reviewed-by: Hannes Reinecke =0A= > =0A= > Cheers,=0A= > =0A= > Hannes=0A= > =0A= =0A= =0A= -- =0A= Damien Le Moal=0A= Western Digital Research=0A=