Received: by 2002:a05:6a10:af89:0:0:0:0 with SMTP id iu9csp6045042pxb; Thu, 27 Jan 2022 05:24:29 -0800 (PST) X-Google-Smtp-Source: ABdhPJypRo5X2FkKxSosZUyKxAXDrIbnHWc1hn2x1zmFBQHYqUm6brrmpoSOcA2Sf4SyFZ90Nkcy X-Received: by 2002:a17:902:b190:: with SMTP id s16mr3417641plr.119.1643289868833; Thu, 27 Jan 2022 05:24:28 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1643289868; cv=none; d=google.com; s=arc-20160816; b=aO4rHlul/k2TUv0zZUZt209SqhKcwihObQFPGzNnhYYDAkSUYbCrfOFgLbRA0OGQLg vcTXl4BkDfzfr9I6onMCBszVo1p8FbN0sMGpHrT8vfRqBI5Dp7XwnKPwIxLBjz+QAzz7 nlReVRkUNA3fiB+27B66aQbvAoZ8nRI+IpsDQCLZnawk52Sj6Z7si/6J8sqs12D/WCie 4DiBmF+WSiLd9W6KsL9O2h8LCghFfjwIUJihxaQOfHvpTsuekeB6NDlig5uw5BdKLevk /AJJq9N4bMnV7pNQK21mS7XL7vMljutylnMImNbT4pnOI0ammSkHGceT1vIJ+GLyupGw kniQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:in-reply-to:from :references:cc:to:content-language:subject:user-agent:mime-version :date:message-id; bh=gB3iq7XstOFbh2uS+JB1WdYrSCQqL7qWjGhInwqR5V4=; b=EeLHCxLcZcSyB8QMkpiiGjtClqNUlIFA1rdkQdg9NjA3Sw07ndhZRNCWbDJdl/y/BS ehu8QMG5IEelCeA4yO6a6VZLjodJpi1K9i1yOswzQ72TZkxP65/IYnmiblMnvziuA+nx 4YmRWlJETwRloLKitX9PcGOYzS0peQc+Oi9hClVEp8xk0WdumJhrbeMUNR/Cv96irj9N q7d32PHaY//FBnUdyoVVzjgGa7GSmqbNgigZqJPBr+8c6dCf43jh57xNhXunxbBOoFfa PvROtq4IDTyvbFo8qk/3s3AbHd2J/Pp8WtNHAG1ZyHYzWJVJsTDniPAy0HzDkMtn50M1 lVSA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id g10si2060197pll.92.2022.01.27.05.24.16; Thu, 27 Jan 2022 05:24:28 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=alibaba.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237107AbiA0HHG (ORCPT + 99 others); Thu, 27 Jan 2022 02:07:06 -0500 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:51914 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229823AbiA0HHE (ORCPT ); Thu, 27 Jan 2022 02:07:04 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04407;MF=jefflexu@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0V2z08g._1643267220; Received: from 30.225.24.48(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0V2z08g._1643267220) by smtp.aliyun-inc.com(127.0.0.1); Thu, 27 Jan 2022 15:07:02 +0800 Message-ID: <8f73d28e-db30-f2e4-0143-9d75c4b13087@linux.alibaba.com> Date: Thu, 27 Jan 2022 15:07:00 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.3.2 Subject: Re: [PATCH v2 00/20] fscache,erofs: fscache-based demand-read semantics Content-Language: en-US To: David Howells Cc: linux-cachefs@redhat.com, xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, joseph.qi@linux.alibaba.com, bo.liu@linux.alibaba.com, tao.peng@linux.alibaba.com, gerry@linux.alibaba.com, eguan@linux.alibaba.com, linux-kernel@vger.kernel.org References: <8f88459a-97e0-8b8d-3ec9-260d482a0d38@linux.alibaba.com> <20220118131216.85338-1-jefflexu@linux.alibaba.com> <2815558.1643127330@warthog.procyon.org.uk> <100895.1643187095@warthog.procyon.org.uk> From: JeffleXu In-Reply-To: <100895.1643187095@warthog.procyon.org.uk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/26/22 4:51 PM, David Howells wrote: > JeffleXu wrote: > >> "/path/to/file+offset" >> ^ >> >> Besides, what does the 'offset' mean? > > Assuming you're storing multiple erofs files within the same backend file, you > need to tell the the cache backend how to find the data. Assuming the erofs > data is arranged such that each erofs file is a single contiguous region, then > you need a pathname and a file offset to find one of them. > Alright. In fact one erofs file can contain multiple chunks, which can correspond to different backing blob files. Thus currently I will use fscache_read() directly, to push this feature forward. Thanks a lot. -- Thanks, Jeffle