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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 722D7C47077 for ; Thu, 11 Jan 2024 05:03:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0HsQvP22IqvAprAUrWo9wX//o45hQJSEEnY0Adf591g=; b=BaWnSelBqNohHjs5mpK/zGxbDE /HCTKdXIEwbnSTi/gLm+M7p2U5gub5f5et69D/wCOgJB3gG+J0njnPnnAiylOLDp+BZetfMiIAVE6 GnvQj2TViGUlj8LBb5AGMTBExwhLqPaKJe7n4qvNcSJEl+QcYePNg9wf9HA/AlgUDF3v8ItFRkZHq Ez8+WF3aDHr2933se1fz65cBJao1KdGwF5lvssCCn+9ocJ4qhsGfZYK1yo4t1Fp3BujF1akJWgtkR K23DHLKE8zNahQaklztSved9lwrNVdxOs+/t9u/KcehshvCdRR0OYjzcLlHp3Jk3kvUUrFG8gZR4m M1cG/3OA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rNnDk-00Ft4e-08; Thu, 11 Jan 2024 05:03:12 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rNnDg-00Ft2z-0N for linux-nvme@lists.infradead.org; Thu, 11 Jan 2024 05:03:09 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 2AD3D68CFE; Thu, 11 Jan 2024 06:02:57 +0100 (CET) Date: Thu, 11 Jan 2024 06:02:57 +0100 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , Dave Chinner , John Garry , axboe@kernel.dk, kbusch@kernel.org, sagi@grimberg.me, jejb@linux.ibm.com, martin.petersen@oracle.com, viro@zeniv.linux.org.uk, brauner@kernel.org, dchinner@redhat.com, jack@suse.cz, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu, jbongio@google.com, linux-scsi@vger.kernel.org, ming.lei@redhat.com, bvanassche@acm.org, ojaswin@linux.ibm.com Subject: Re: [PATCH v2 00/16] block atomic writes Message-ID: <20240111050257.GA4457@lst.de> References: <20231219051456.GB3964019@frogsfrogsfrogs> <20231219052121.GA338@lst.de> <76c85021-dd9e-49e3-80e3-25a17c7ca455@oracle.com> <20231219151759.GA4468@lst.de> <20231221065031.GA25778@lst.de> <73d03703-6c57-424a-80ea-965e636c34d6@oracle.com> <20240110091929.GA31003@lst.de> <20240111014056.GL722975@frogsfrogsfrogs> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240111014056.GL722975@frogsfrogsfrogs> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240110_210308_301010_269F4D9A X-CRM114-Status: GOOD ( 12.62 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Jan 10, 2024 at 05:40:56PM -0800, Darrick J. Wong wrote: > struct statx statx; > struct fsxattr fsxattr; > int fd = open('/foofile', O_RDWR | O_DIRECT); > > ioctl(fd, FS_IOC_GETXATTR, &fsxattr); > > fsxattr.fsx_xflags |= FS_XFLAG_FORCEALIGN | FS_XFLAG_WRITE_ATOMIC; > fsxattr.fsx_extsize = 16384; /* only for hardware no-tears writes */ > > ioctl(fd, FS_IOC_SETXATTR, &fsxattr); > > statx(fd, "", AT_EMPTY_PATH, STATX_ALL | STATX_WRITE_ATOMIC, &statx); > > if (statx.stx_atomic_write_unit_max >= 16384) { > pwrite(fd, &iov, 1, 0, RWF_SYNC | RWF_ATOMIC); > printf("HAPPY DANCE\n"); > } I think this still needs a check if the fs needs alignment for atomic writes at all. i.e. struct statx statx; struct fsxattr fsxattr; int fd = open('/foofile', O_RDWR | O_DIRECT); ioctl(fd, FS_IOC_GETXATTR, &fsxattr); statx(fd, "", AT_EMPTY_PATH, STATX_ALL | STATX_WRITE_ATOMIC, &statx); if (statx.stx_atomic_write_unit_max < 16384) { bailout(); } fsxattr.fsx_xflags |= FS_XFLAG_WRITE_ATOMIC; if (statx.stx_atomic_write_alignment) { fsxattr.fsx_xflags |= FS_XFLAG_FORCEALIGN; fsxattr.fsx_extsize = 16384; /* only for hardware no-tears writes */ } if (ioctl(fd, FS_IOC_SETXATTR, &fsxattr) < 1) { bailout(); } pwrite(fd, &iov, 1, 0, RWF_SYNC | RWF_ATOMIC); printf("HAPPY DANCE\n");