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[2604:1380:40f1:3f00::1]) by mx.google.com with ESMTPS id nn16-20020a17090b38d000b002a0493ae5bbsi13918571pjb.111.2024.04.02.05.41.22 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Apr 2024 05:41:22 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel+bounces-127933-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1; Authentication-Results: mx.google.com; arc=pass (i=1 spf=pass spfdomain=lst.de); spf=pass (google.com: domain of linux-kernel+bounces-127933-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) smtp.mailfrom="linux-kernel+bounces-127933-linux.lists.archive=gmail.com@vger.kernel.org" Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sy.mirrors.kernel.org (Postfix) with ESMTPS id 63DABB22B39 for ; Tue, 2 Apr 2024 12:26:40 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6C8A578286; Tue, 2 Apr 2024 12:26:29 +0000 (UTC) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB8BA762DC; Tue, 2 Apr 2024 12:26:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712060788; cv=none; b=AyIf4eGC6esLVrI20udvMGCWM+i7qlri0+dTIubDWy2wI2NjiRLJOwobCbJlBdCV7JQAUKoxdN5dSgMyDIn+jRPVPdw4w4+E5OIvhjraLSrf0zfF9w/Vds3wNP9iBH9C2+or+ojNZCSKhtse2uY3VeIWz2MpogVdvZjWPCY+Rdw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712060788; c=relaxed/simple; bh=wRqxX1ZdzTg1ypcfFu9ZTj5oUiFKc90eBb8f5dzWCJ8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=so4PYfJ3pdF1BOeADzHKgsT/MThlBPHMNwDiO2kzBk5tGA0Uo1ql184x5qV9I1uiV8ncKcnN8M5u4iof/W0+D8a/I6Yylq5Ph3M2khKrXnT2oeT/qo+xMrSkcv4bevTl+QbzvWMCb1VmoMO/ksXn0iIOFsHaCOx7bFMST9CUhpM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 5C1BB68BFE; Tue, 2 Apr 2024 14:26:17 +0200 (CEST) Date: Tue, 2 Apr 2024 14:26:17 +0200 From: Christoph Hellwig To: Stefan Hajnoczi Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, eblake@redhat.com, Alasdair Kergon , Mikulas Patocka , dm-devel@lists.linux.dev, David Teigland , Mike Snitzer , Jens Axboe , Christoph Hellwig , Joe Thornber Subject: Re: [RFC 0/9] block: add llseek(SEEK_HOLE/SEEK_DATA) support Message-ID: <20240402122617.GA30720@lst.de> References: <20240328203910.2370087-1-stefanha@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240328203910.2370087-1-stefanha@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) On Thu, Mar 28, 2024 at 04:39:01PM -0400, Stefan Hajnoczi wrote: > In the block device world there are similar concepts to holes: > - SCSI has Logical Block Provisioning where the "mapped" state would be > considered data and other states would be considered holes. But for SCSI (and ATA and NVMe) unmapped/delallocated/etc blocks do not have to return zeroes. They could also return some other initialization pattern pattern. So they are (unfortunately) not a 1:1 mapping to holes in sparse files.